Purification and some properties of three forms of glucoamylase from a Rhizopus species. 1. Three forms of glucoamylase [EC 3.2.1.3] were simultaneously purified from a Rhizopus species by (NH4)2SO4 fractionation and successive chromatographies on Sephadex G-75, DEAE-Sephadex, and CM-Sephadex, and were finally separated from each other by means of recycling chromatography on Bio-Gel P-150. The purification achieved was 3--4 fold from crude extract with respect to each glucoamylase; the yields of the three glucoamylases, designated as Gluc1, Gluc2, and Gluc3 in order of content, were 39, 7, and 0.4%, respectively. All the purified enzymes were homogeneous in polyacrylamide gel electrophoresis, isoelectric focusing, and ultracentrifugation. 2. The three glucoamylases were glycoproteins differing in both amino acid composition and carbohydrate content, but showed a common antigenicity in immunodiffusion. The molecular weights of Gluc1, Gluc2, and Gluc3 were estimated to be 74,000, 58,600, and 61,400, respectively, by sedimentation equilibrium and these values were verified by SDS-polyacrylamide gel electrophoresis. The specific activities of the three enzymes toward starch were in the opposite order to their molecular weights. 3. The three glucoamylases had the same broad pH optima in the range pH 4.5--5.0 and shared a common susceptibility to inactivation by heat, extreme pH, and such divalent cations as Hg2+, Pb2+, and Mn2+, indicating close similarity in enzymatic properties.


Direct fluorometric determination of a dissociation constant as low as 10(-10) M for the subtilisin BPN'--protein proteinase inhibitor (Streptomyces subtilisin inhibitor) complex by a single photon counting technique. It was found that an increase in fluorescence intensity at 340 nm is observed on the binding of Streptomyces subtilisin inhibitor (SSI) with subtilisin BPN' in the pH range 6--10. The dissociation constant, Ki, of the enzyme-inhibitor complex was determined as a function of pH and temperature by direct fluorometric titration utilizing the single photon counting technique in the protein concentration range of 10(-9) M. Ki values as low as 10(-10) M could be obtained with reasonable accuracy by this high-sensitivity detection method. From the temperature dependence of Ki, it was found that the binding is endothermic, and is entirely "entropy-driven" in nature. The effect of pH on Ki suggested the participation of an ionizable group with pKapp = 8.5 in the binding.


Enzymic acetylation of nucleosome histone. Rat liver chromatin prepared from purified nuclei catalyzed the acetylation of histones in nucleosomes at the same level as that of nuclei. The activity of histone acetyltransferase in chromatin was destroyed by heat treatment at 65 degrees C for 5 min. Histones in exogenously added nucleosomes also served as substrate for the enzyme. The sites of acetylation in the nucleosomes appeared to be in the trypsin-digestable N-terminal regions of histones H4, H3, and H2A, as has been reported in an in vivo system.


Purification and properties of an exo-cellulase of Avicelase type from a wood-rotting fungus, Irpex lacteus (Polyporus tulipiferae). A cellulase component of Avicelase type was obtained from Driselase, a commercial enzyme preparation from a wood-rotting fungus Irpex lacteus (Polyporus tulipiferae). It showed a single band on SDS-polyacrylamide electrophoresis. The amino acid composition of this cellulase resembled those of cellulase components of endo-type from the same fungus. However, it produced exclusively cellobiose from CMC as well as from water-insoluble celluloses such as Avicel or cotton at earlier stages of hydrolysis. In addition, the hydrolysis of CMC practically stopped after an initial rapid stage. The cellulase showed a strong synergistic action with an endo-cellulase of higher randomness (typical CMCase-type) in the hydrolysis of CMC as well as Avicel. In contrast to cellotriose and -tetraose, cellopentaose and -hexaose were attacked very rapidly, and only cellobiose was produced. These results suggest that the cellulase is an exo-type component. However, it mutarotated the products from cellopentaitol in the same direction as endo-cellulases. it represented a relatively large portion of the total cellulase activity, and may play an important role in the degradation of native cellulose in vivo.


Peptide bond synthesis catalyzed by alpha-chymotrypsin. alpha-Chymotrypsin [EC 3.4.21.1] catalyzed the syntheses of peptide bonds with various N-acylated amino acids or peptides having aromatic or hydrophobic amino acid residues at the C-terminal position as carboxyl components, and amino acid derivatives, peptides or their derivatives as amine components. A neutral pH was most efficient and quite high concentrations of alpha-chymotrypsin and starting materials were required for synthesis. Four amine components, hydrophobic or bulky amino acid residues were useful at the N-terminal position. Stereospecificity was also observed at the N-terminal position of amine components. Peptide synthesis was not usually seen when the products were soluble in the reaction mixture. This could be partly overcome by increasing the concentration of either the carboxyl or the amine component to more than ten times that of the other.


Bacteriorhodopsin induces a light-scattering change in Halobacterium halobium. When suspensions of Halobacterium halobium are exposed to bright light, the light-scattering properties of the bacteria change. This light-scattering response can produce a transmission decrease of about 1% throughout the red and near-infrared region. The action spectrum for the light-scattering response appropriately matches the absorption spectrum of bacteriorhodopsin. The response is eliminated by cyanide p-trifluoro-methoxyphenylhydrazone, a proton ionophore, and by triphenylmethylphosphonium, a membrane permanent cation. A mild hypertonic shock induces a similar light-scattering change, suggesting that bright light causes the bacteria to shrink about 1% in volume, thereby producing the light-scattering response.


Evaluation of weighted discriminating power calculations as an aid to the selection of chromatographic systems for the analyses of drugs. In toxicological analyses some chromatographic separations are more important than others. Two weighting methods for chromatographic data are described which incorporate the importance of particular separations into discriminating power calculations. The data were abstracted from a publication on the separations of acidic drugs on thin-layer chromatographic systems. When compared with non-weighted discriminating power calculations, those obtained with the weighting procedure did not give any advantage.


Choice of thin-layer chromatographic systems for the routine screening for neutral drugs during toxicological analyses. The efficiencies of fifteen thin-layer silica gel chromatographic systems for separating commonly encountered neutral drugs are compared. The discriminating powers of the systems are measured both individually and in combination. Chloroform-acetone (4:1) is found to be the best system. The combination of the ethyl acetate-methanol-ammonia (85:10:5) system with this gives the best pair of systems. A suitable sequence of spray reagents is also suggested. The chloroform-acetone (4:1) system is recommended as the best system to use when screening for both acidic and neutral drugs.


Choice of thin-layer chromatographic systems for the routine screening for acidic drugs during toxicological analyses. The efficiencies of fifteen thin-layer silica gel chromatographic systems in separating commonly encountered acidic drugs are compared. The discriminating powers of the systems are measured both individually and in combination. Ethyl acetate and chloroform-methanol (9:1) are found to be the two best systems. The combination of the ethyl acetate-methanol-ammonia (85:10:5) system with either of these gives the best pair of systems. Various sequences of spray reagents are also examined.


Precipitate produced by Serratia marcescens on MacConkey agar: useful diagnostic test. The production of a precipitate by Serratia marcescens on Oxoid MacConkey agar has proven useful as a laboratory diagnostic test. This phenomenon is specific for Serratia within the Enterobacteriaceae, although precipitate production is also given by Acinetobacter anitratus and some Pseudomonas, Alcaligenes, and Aeromonas species. Precipitate production seems to be specific for certain batches of MacConkey agar, and is probably related to a specific property of some batches of bile salts.


Appraisal of ascorbic acid for acidifying the urine of methenamine-treated geriatric patients. A study was made of 73 elderly patients receiving methenamine and ascorbic acid concurrently. Each patient had an indwelling Foley catheter. Urinary pH was assessed in relation to the dosage of ascorbic acid, duration of therapy, formulation, and dosing intervals for ascorbic acid and methenamine. Statistical analysis revealed a significant increase in urinary pH when the dosage of ascorbic acid was increased. No significant relationships were found between urinary pH and the dosage forms of ascorbic acid, the salt of methenamine used, or the duration of methenamine therapy. Changes in urinary pH at different dosing intervals for ascorbic acid were found to be significant, at the 10 percent level only, for the three-times-daily dose schedule. These data raise a question as to the value of ascorbic acid for acidifying the urine of catheterized patients receiving methenamine therapy.


[The value of measuring blood pH in fetal monitoring during labour (author's transl)]. The authors present a series of methodological studies carried out to assess the value of the place of measuring fetal blood pH in monitoring in labour. Comparisons of the measures of pH, pCO2, pO2 and lowering of the base were carried out on the scalp in the 3 minutes which preceded the birth and in the umbilical vessels at birth. Comparing the three modes of taking blood in the mother, intra-arterially and from the capillaries with and without local vasodilatation was carried out. The limits of the values were defined both for the fetus and the mother of the parameters of pH, pCO2, pO2 and base deficit in 100 normal deliveries. A study was carried out of their correlations with the Apgar score at 1 minute and with the arterial pH. A comparison of the two series of measurements was carried out on the vessels of the cord--arterial and venous. The results confirm the value of measuring pH for diagnosing the state of the infant during labour.


A kinetic study of the reaction between glutaraldehyde and horseradish peroxidase. Horseradish peroxidase was reacted with glutaraldehyde under various reaction conditions. The reaction product was, in a second step, bound covalently to aminohexyl groups attached to Sepharose particles. The influence of pH, time and the concentration ratio of enzyme:glutaraldehyde on the reaction was evaluated. A first step reaction with 100-fold molar excess of glutaraldehyde to horseradish peroxidase at pH 9.5 for 2 hr at room temperature results in a high yield of conjugated enzyme with well preserved enzymatic activity.


The effect of fostering nude mice with allogeneic mothers on subsequent mortality. Mortality in nude mice fostered by allogeneic mothers was studied. The data failed to support the hypothesis that mortality was due to graft versus host disease resulting from the passage of immunocomponent cells to the young in the mothers' milk. It was apparent that there were significant differences in the ability of mothers of different strains to rear nude mice.


[The dental soldering by means of high frequency induction heating (author's transl)]. The authors examined the methods of high frequency induction soldering, especially Loop-method, other than the gas flame soldering which was known generally. The details which was done are: (1) about the form of induction coil, and the relative places of the coil and restrative appliance, and some supplementary appliances of them. (2) about strength of soldered joints of Co-Cr wire using silver solder and Pd-solder, and observation on the corrosion of soldered-joints by the scanning electron-microscope. (3) about the comparison of the characteristics of Co-Cr wire by means of high-frequency induction heating and gas-flame one. (4) about the examples of soldering of porcelain crown-bridge and clasp wire attached on the dental cast, and possibility of soldering techniques of them on the dental cast. The authors found that the high frequency induction method was preeminent from the other method on the point of (a) the characteristic of heated wire, (b) the strength of soldered joints, (c) the easiness of operating of them, and (d) the possibility of soldering using the high-melting point of Pd-solder, and the soldering of them on the dental cast. Therefore we can enough respect the application on the dental area of this apparatus and this techniques of the high-frequency induction soldering.


Quantification of apoC-II and apoC-III of human very low density lipoproteins by analytical isoelectric focusing. ApoC-II and apoC-III of human very low density lipoproteins (VLDL) have been quantified by analytical isoelectric focusing (IEF) between pH 4 and 6 in polyacrylamide gels containing 8 M urea. The isoelectric point of apoC-III0 is pH 4.93; apoC-II, pH 4.78; apoC-III1, pH 4.72, and apoC-III2, pH 4.54. ApoC-I is not found in the pH range between pH 4 and 6. Two minor peptides, apoC-IV and apoC-V, with isoelectric points of pH 4.61 and 4.44, respectively, are apoproteins not previously identified. The sensitivity (5--40 microgram) and reproducibility (+/- 8%) of this method allow quantitative analysis of apoC-II and apoC-III distribution in VLDL.


The major fraction of deoxyribonuclease activity from human urinary proteins. Purification and properties. The major fraction of deoxyribonuclease activity from human urinary protein was purified 40-fold in about 14% yield. The enzyme shows an isoelectric point at pH 4.2 and has a molecular weight of 33,600+/-3,000. Optimum activity was shown at pH 6.8 in the presence of 12.5 mmol/l Mg2+ plus 1 mmol/l Ca2+. The enzymic reaction is inhibited by high ionic strength (greater than 300 mmol/l Na+). The purified enzyme readily hydrolyzes native DNA to oligodeoxyribonucleotides with an average chain length of 5.3+/-0.2 after exhaustive digestion. Therefore, this endonuclease may be designated as neutral deoxyribonuclease (deoxyribonucleate oligonucleotidohydrolase, EC 3.1.4.5).


Net charge and oxygen affinity of human hemoglobin are independent of hemoglobin concentration. The dependence of net charge and oxygen affinity of human hemoglobin upon hemoglobin concentration was reinvestigated. In contrast to earlier reports from various laboratories, both functional properties of hemoglobin were found to be independent of hemoglobin concentration. Two findings indicate a concentration-independent net charge of carbonmonoxy hemoglobin at pH 6.6: (A) The pH value of a given carbonmonoty hemoglobin solution remains constant at 6.6 when the hemoglobin concentration is raised from 10 to 40 g/dl, indicating that there is no change in protonation of titratable groups of hemoglobin: (b) the net charge of carbonmonoxy hemoglobin as estimated from the Donnan distribution of 22Na+ shows no dependence on hemoglobin concentration in this concentration range. The oxygen affinity of human hemoglobin was determined from measurements of oxygen concentrations in equilibrated samples using a Lex-O2-Con apparatus (Lexington Instruments, Waltham, Mass.). P50 averaged 11.4 mm Hg at 37 degrees C, pH = 7.2, and ionic strength approximately 0.15. Neither P50 nor Hill's n showed any variation with hemoglobin concentrations increasing from 10 to 40 g/dl.


Models for assessing the effect of toxicants on immunocompetence in mice. II. Effect of cyclophosphamide on the antibody responses to type III pneumococcal polysaccharide and tetanus toxoid in BALB/c female mice. A mixture of antigens was used to detect alterations in immunocompetence. Type III pneumococcal polysaccharide (S3) and tetanus toxoid (TT) stimulate different cellular components, and can therefore be used to assess different compartments of the immune mechanism. Cyclophosphamide (CP), a known immunosuppressant, had a potent effect upon the antibody responses to both S3 and tetanus toxoid. All doses of CP administered within 2 days of priming with S3 resulted in a dose-related immunosuppressive action which persisted even after reinjection of S3. 300 mg/kg of CP given up to 14 days prior to or following primary immunization resulted in a marked suppression of antibodies to S3. Doses of S3 which were partially tolerogenic were made even more so by injections of CP. The effect persisted over a 96 day experimental period. CP also suppressed the formation a memory cells necessary for induction of a secondary-type IgG response to TT. The time of injection for maximum suppression was days 10 to 14 after priming. Therefore, the suppression must involve cellular mechanisms different from those responsible for S3 antibody suppression. In addition, there was a difference in the degree and persistence of the suppressive effect, since the suppressed animals were able to mount an immune response to subsequent injections of TT. Double injections of a high dose (300 mg/kg) of CP 4 weeks after priming completely suppressed the acquired immunity to both S3 and TT. Low and moderate doses of CP appeared to induce a mild augmentation of S3 antibody response when given 4 weeks after priming. However, an immunosuppressive effect occurred if the primed animals were reinjected with S3 or challenged with TT within a period of 2 days prior to or after receiving the CP treatment. Doses of CP, injected prior to challenge and resulting in suppressed tetanus antitoxin production, elevated the titers of specific IgE antibody. This class of antibody is associated with adverse hypersensitivity reactions. These data provided background for the development of models to assess immunocompetence in mice, based on a study of immune profiles following exposure to selected T-dependent and T-independent antigens. Such models may be used to detect potentially hazardous chemicals found in the environment of incorporated into foods, drugs, or cosmetics.


Polychlorinated biphenyls: in vivo and in vitro modifications of cholesterol and fatty acid biosynthesis. Aroclor 1254 (0.1 percent w/w) administered in the diet caused moderate to severe vacuolar degeneration of periportal hepatocytes, heptocyte enlargement, lipid accumulation, and necrosis of the liver. The incorporation of [2-14C]mevalonate into nonsaponifiable lipids was inhibited 18 percent and 26 percent after 14 days and 30 days, respectively. Biosynthesis of cholesterol from [2-14C]acetate and [2-14C]mevalonate was decreased by 51 percent and 31 percent respectively after 30 days, but no significant inhibition was observed after 14 days of feeding Aroclor 1254. [2-14C]Acetate incorporation into non-saponifiable lipids was 1.66 times greater in homogenates from Aroclor-treated rats than in those from control rats. Similar results were obtained when 3H2O, Mevalonate-14C, and acetate-2-14C were incubated in vivo. The conversion of [2-14C-A1acetate to fatty acids was decreased 43 percent by Aroclor 1254 (0.1 percent w/w, dietary) and 73 percent by Aroclor 1254, 500 ppm, in vitro. The in vitro incorporation of each [2-14C]acetate, [2-14C]mevalonate and [1-14C]isopentenyl pyrophosphate into cholesterol was inhibited by Aroclor 1254. There was no inhibition of the conversion of [1-14C]mevalonate to CO2, indicating that there was no inhibition of mevalonate-5-pyrophosphate anhydrodecarboxylase. Fatty acid synthase was not inhibited by PCB. Citrate cleavage enzyme was inhibited by Aroclor 1254. When ATP and citrate concentrations were varied, the Ki's were 5.3 X 10(-5)M and 11.5 X 13(-5)M, respectively. Acetyl CoA carboxylase activity was not inhibited by 1000 ppm Aroclor 1254 in vitro. Inhibition of citrate cleavage enzyme is a possible explanation for the observed decrease in fatty acid synthesis. There was an apparent diversion of acetate from fatty acid synthesis into the formation of non-saponifiable lipids, accompanied by an inhibition of the biosynthesis of cholesterol per se.


Purification and properties of an NAD(P)+-linked formaldehyde dehydrogenase from Methylococcus capsulatus (Bath). Crude soluble extracts of Methylococcus capsulatus strain Bath, grown on methane, were found to contain NAD(P)+-linked formaldehyde dehydrogenase activity. Activity in the extract was lost on dialysis against phosphate buffer, but could be restored by supplementing with inactive, heat-treated extract (70 degrees C for 12 min). The non-dialysable, heat-sensitive component was isolated and purified, and has a molecular weight of about 115000. Sodium dodecyl sulphate gel electrophoresis of the protein suggested there were two equal subunits with molecular weights of 57000. The heat-stable fraction, which was necessary for activity of the heat-sensitive protein, was trypsin-sensitive and presumed to be a low molecular weight protein or peptide. A number of thiol compounds and other common cofactors could not replace the component present in the heat-treated soluble extract. The purified formaldehyde dehydrogenase oxidized three other aldehydes with the following Km values: 0.68 mM (formaldehyde); 0.075 mM (glyoxal); 7.0 mM (glycolaldehyde); and 2.0 mM (DL-glyceraldehyde). NAD+ or NADP+ was required for activity, with Km values of 0.063 and 0.155 mM respectively, and could not be replaced by any of the artificial electron acceptors tested. The enzyme was heat-stable at 45 degrees C for at least 10 min and had temperature and pH optima of 45 degrees C and pH 7.2 respectively. A number of metal-binding agents and substrate analogues were not inhibitory. Thiol reagents gave varying degrees of inhibition, the most potent being p-hydroxymercuribenzoate which at 1 mM gave 100% inhibition. The importance of possessing an NAD(P)+-linked formaldehyde dehydrogenase, with respect to M. capsulatus, is discussed.


Anaerobic transport of serine and 2-aminoisobutyric acid by Staphylococcus epidermidis. A membrane-bound ATPase detected in extracts of anaerobically grown Staphylococcus epidermidis was inhibited by a variety of compounds which inhibit ATPases in other organisms. Serine and 2-aminoisobutyric acid (AIB) were shown to enter the organism via the same transport system. The transport of AIB, the membrane potential and the transmembrane pH gradient were partially or completely abolished by the same inhibitors and also by uncoupling agents and lipid-soluble ions. It is proposed therefore that this ATPase generates and maintains an electrochemical gradient of protons across the cytoplasmic membrane of S. epidermidis capable of driving AIB uptake. Studies of AIB-induced proton movements suggested that AIB enters via a proton symport mechanism.


Kleine-Levin syndrome with periodic apnea during hypersomnic stages--E.E.G. study. A 33 year old male, suffering from Kleine-Levine syndrome associated with periods of apnea during the hypersomnic attacks, is reported. Ventilatory studies negate the Pickwickian syndrome. The E.E.G.'s recorded during the hypersomnic attacks and the apneic periods showed a direct correlation between high-voltage delta waves paroxysmal E.E.G. activity, and apneic period. Medications known to improve Kleine-Levin syndrome, in our case, had no effect upon the clinical hypersomnic and apnea periods, nor on the correlatives E.E.G.'s pattern and spirometric studies. Theoretical considerations let us assume that these paroxysmal E.E.G. patterns associated with apnea are NRem-sleep serotonin dependent, and have an inhibitory influence on the respiratory centers, by alternating the equilibrium between the catecholamines and acetylcholine activities.


Role of vitamin B12 and enzymes related to methylmalonyl-CoA mutase in a methanol-utilizing bacterium, Protaminobacter ruber. A methanol-utilizing bacterium, Protaminobacter ruber, required cobalt ion or vitamin B12 as its growth factor, which could be replaced by succinate among various additions to the cobalt-deficient medium. The presence of adenosylcobalamin (adenosyl-B12)-dependent methylmalonyl-coenzyme A (CoA) mutase was demonstrated in the cell-free extracts of P. ruber. The specific activity of this mutase was not only fairly high in comparison with that reported with other organisms but also detected at a similar level throughout the cultivation period. The cell-free extracts of P. ruber grown on non-C1 compounds as a sole carbon and energy source also had methylmalonyl-CoA mutase activity. Furthermore, the extracts of this microorganism catalyzed the reactions from propionyl-CoA to succinyl-CoA and from alpha-ketoglutarate to alpha-hydroxyglutarate.


Use of intraoperative esophageal manometrics in surgical treatment of gastroesophageal reflux in pediatric patients. Intraoperative lower esophageal sphincter (LES) pressures and lenghts were measured in 10 pediatric patients requiring surgery for compications of gastroesophageal reflux. LES pressure changed significantly pre- and post-Nissen fundoplication (9.8 +/- 1.51 mm Hg vs. 32.8 +/- 2.68 mm Hg, p less than 0.001). LES length also showed a significant change (1.3 +/- 0.13 cm vs. 2.8 +/- 0.26 cm, p less than 0.001). One week postoperatively LES pressures were significantly greater than preoperative values (26.4 +/- 1.74 mm Hg vs. 15.6 +/- 2.64 mm Hg, p less than 0.01). Eight of 10 patients have been evaluated 6 mo post fundoplication. None has gastroesophageal reflux by acid reflux testing or water siphon barium esophagram. None of the 10 patients has had gas bloat syndrome during the follow-up period.


Content uniformity of potent drugs in tablets. The type of distribution of low dosage drugs that occurs in batches of commercially available tablets has been examined. The uniformity of content of ethinyloestradiol tablets 10 micrograms B.P. from different sources, assessed by single tablet assay showed that three batches exhibited some positive skewness and one marked positive skewness. At the high level of dilution required, the mixing theory indicates that particles of drug must be very fine if acceptable content uniformity is to be obtained. Cohesion of particles impairs the efficiency of the mixing process. It is shown theoretically that unless the drug is dispersed into its component particles the shape of the distribution curve for the content of drug per tablet, in a batch of tablets, will be positively skewed. The relation between the tensile strength of the powdered drug and the degree of skewness of the drug content is also discussed. A positively skewed distribution for tablets containing a small amount of potent drug is unacceptable because this can lead to the presence of relatively large doses of drug in a single tablet. Where one unexpectedly high result occurs in the quality control of the content uniformity of tablets containing potent drugs it is suggested that sufficient single tablet assays be performed to allow the shape of the distribution curve to be assessed. A test for skewness should be included in compendial standards.


The effect of the photodecomposition of chlorpromazine on lecithin monolayers. Chlorpromazine hydrochloride (cpz) is decomposed when irradiated with ultraviolet light, forming H+, hydrochloric acid, chlorpromazine sulphoxide and 2-hydroxypromazine. The order of the reaction (as measured by the expansion that is produced in a lecithin/cpz monolayer) varies between zero and about 3/4. The results have been used to explain some of the adverse side effects that are observed when patients are treated with cpz.


Gastric ulceration and the concentration of salicylate in plasma in rats after administration of 14C-labelled aspirin and its synthetic triglyceride, 1,3-dipalmitoyl-2(2'-acetoxy-[14C]carboxylbenzoyl) glycerol. Triglycerides containing aspirin in place of one or more fatty acid residues of the molecule have been synthesized. Metabolism of the compound with the labelled (14C) drug residue introduced specifically into the 2-position of the triglyceride is reported. Plasma salicylate concentrations with this synthetic glyceride were determined and compared with those obtained with commercially available aspirin labelled with the 14C-isotope. Both compounds gave a therapeutic concentration of salicylate in the plasma after ingestion. The 1,3-di-fatty acyl-2-aspirin glyceride was absorbed through the intestine as 2-aspirin monoglyceride, some 20% of which was transported through the thoracic-duct chyle and about 30% through the portal system. Whereas pronounced ulceration of the rat stomach occurred with free aspirin, the above fatty acyl glyceride of aspirin produced no ulceration.


The effects of a decarboxylase inhibitor, benserazide, on both thermoregulation and chlorpromazine-induced hypothermia in rats. Intraperitoneal administration of a peripheral decarboxylase inhibitor benserazide (Ro4-4602) to unanesthetized rats produced alterations in body temperature which depended on ambient temperature. In the cold, hypothermia was brought about by a decrease in metabolic heat production. At room temperature, a dose-dependent hypothermia was preceded by a slight hyperthermia. The hypothermia was due to an increase in skin temperature (tail) and a decrease in metabolic heat production, while the hyperthermia was due to a decrease in skin temperatures (both tail and footsole) and an increase in metabolic heat production. In the heat, hyperthermia responses to benserazide were associated with decrease in skin temperature (both tail and footsole). Benserazide treatment produced no significant change in brain 5-HT content. Chlorpromazine-induced hypothermia was greatly enhanced after pretreatment of the animals with benserazide at room temperature (22 degrees).


The effect of PGE1 on peristalsis and on perivascular nerve inhibition of peristaltic activity in guinea-pig isolated ileum. The effect of PGE1 on peristalsis of guinea-pig isolated ileum was examined using a modified Trendelenburg method to evoke and record peristaltic activity. PGE1 (14 nM, 0.11 microM and 0.56 microM) increased peristaltic activity of both longitudinal and circular muscle, mainly by increasing the amplitude of contraction. Preparations of ileum subjected to a 'minimal' peristaltic stimulus were more sensitive to the effects of PGE1 than were preparations subjected to a 'just-maximal' peristaltic stimulus. The inhibition of peristaltic activity caused by perivascular nerve stimulation was antagonized by 0.56 microM PGE1 but slightly increased by 14 nM PGE1.


Hypertension: its effect on the stimulated release of dopamine-beta-hydroxylase in the rat. Plasma dopamine-beta-hydroxylase (DBH) concentrations have been postulated as providing an index of sympathetic nerve activity. Using a microspectrophotometric assay system, plasma DBH concentrations have been measured in emergent blood from autoperfused heart, spleen and mesentery of normotensive, deoxycorticosterone (doca)/NaCl-treated, Goldblatt (1 kidney) renal and spontaneously hypertensive rats following sympathetic nerve outflow stimulation. Changes in plasma DBH concentrations as a result of sympathetic nerve outflow stimulation rates of 1--25 Hz for the mesentery and spleen and 1--4 Hz for the heart, were found to be frequency-dependent in all groups. Significantly greater amounts of DBH were found in the perfusate from the spleen (1--25 Hz) and mesentery (3--25 Hz) but not the heart (0.5--4Hz) of renal hypertensive rats compared with normotensive controls. Significantly greater concentrations of DBH were released from the spleen but not the mesentery in all hypertensive groups following high stimulation frequencies of 12 and 25 Hz. It is concluded that there is a relation between plasma DBH concentrations and sympathetic nerve activity. Furthermore, greater amounts of the enzyme are released from the spleen and mesentery of chronic renal hypertensive rats following sympathetic nerve stimulation.


The release of a model low-dose drug (riboflavine) from hard gelatin capsule formulations. The in vitro release of a model low dose drug, riboflavine, from hard gelatin capsules, formulated with a range of diluents, in the absence and presence of magnesium stearate (0.5, 1.0 and 2.0% w/w), has been assessed by a dissolution technique. Comparison of the values of the time for 50% of the drug content of the capsule to appear in solution T50, by analysis of variance, indicated that the type of diluent significantly influenced the drug release. Irrespective of the magnesium stearate content, the diluents could be ranked in the following order of effectiveness: Primojel greater than sodium bicarbonate greater than Avicel congruent to Dri-flo starch congruent to lactose greater than Emcompress congruent to kaolin greater than starch. Correction of the T50 values for possible adsorption of riboflavine onto the water insoluble diluents, using experimentally determined adsorption isotherms, altered the relative order of effectiveness of the diluents to Primojel greater than sodium bicarbonate greater than kaolin congruent to lactose greater than Avicel congruent to Dri-flo starch greater than Emcompress greater than starch. Comparison of the urinary excretion of riboflavine, after administration of capsule formulations containing lactose, Emcompress or kaolin as the diluent, to volunteers, suggests that the dissolution results not corrected for adsorption provide a better indication of the in vivo performance of the formulations.


An in vitro method simulating drug release from viscous eye drops in rabbit and man. A method has been developed using a diffusion cell in an attempt to determine the drug release from viscous solutions under conditions simulating the blinking movements in the rabbit and human eye. Diffusion coefficients were determined at rest and at different velocities. For the solutions at rest, corresponding with the conditions at the surface of the rabbit cornea, the diffusion velocity decreases with increasing viscosity. When the solution is moved at a velocity corresponding to that of lachrymal fluid at the surface of the human eye, the influence of viscosity may be neglected.


A comparison of the cardiovascular effects of centrally administered clonidine and adrenaline in the anaesthetized rat. Intracerebroventricular (i.c.v.) injections of clonidine and adrenaline-induced hypotension and bradycardia in urethane anaesthetized spontaneous hypertensive rats. The hypotension induced by clonidine (3 microgram i.c.v.) was antagonized by pretreatment with the alpha-antagonists piperoxan, which also antagonized clonidine-induced bradycardia, and yohimbine. The hypotension and bradycardia induced by adrenaline (10 microgram i.c.v.) were unaffected by alpha-antagonist pretreatment, while beta-antagonist pretreatment with (--)-propranolol or metoprolol was effective against adrenaline but not clonidine-induced hypotension and bradycardia. Pretreatments with the histamine H2-receptor antagonists metiamide and cimetidine antagonized clonidine but not adrenaline-induced hypotension. These data indicate that different central mechanisms are involved in mediating the hypotension and bradycardia induced by centrally administered clonidine and adrenaline and do not, therefore, support the hypothesis that the hypotensive effects of clonidine (i.c.v.) are mediated by central adrenaline receptor activation in urethane-anaesthetized spontaneous hypertensive rats.


Long-lasting inhibition of angiotensin response in rats by depot administration of octanoyl-[Leu8]-angiotensin II. Depot administration of a lipophilic angiotensin II (AII) antagonist was tested for obtaining prolonged inhibition of the pressor response to AII in rats. Intramuscular injections of 1.5 or 5.0 mg of octanoyl-[Leu8]AII (oct-LAII), in oil solution produced the same degree of AII inhibition either 6 h or 24 h after the injection. The inhibition was comparable to that expected from the continuous intravenous infusion of oct-LAII at the rate of 1.2 microgram kg-1 min-1. The prolonged effect of intramuscular injections of oct-LAII in oil solution may be useful for chronic studies of physiopathological states involving the renin-angiotensin-aldosterone system.


Plasma corticosterone responses to stress following chronic oral administration of diazepam in the rat. The effect of daily, oral administration of diazepam on plasma corticosterone responses to stressors of varying intensity was investigated. In rats exposed to the mild stress of noise, diazepam, 10 mg kg-1 but not 1.0 or 0.1  mg kg-1, reduced plasma corticosterone concentrations by 30% in comparison with controls. However, in rats exposed to the more severe stressors, foot-shock or immobilization, none of these doses of diazepam reduced plasma corticosterone responses. In unstressed rats, diazepam 10 mg kg-1 raised plasma corticosterone concentrations. It is suggested that plasma corticosterone concentrations are not a reliable indicator of the tranquillizing effect of diazepam during stress.


p-Chloroamphetamine-induced hyperthermia pharmacologically distinct from fenfluramine-induced hyperthermia. The influence of various drug pretreatments upon the responses of rabbits to the putative indirect 5-hydroxytryptaminergic agonists p-chloroamphetamine (PCA) and fenfluramine were examined. In naive rabbits PCA evoked hyperthermia, behavioural excitation and prominent forepaw clonic activity, while fenfluramine produced only hyperthermia and behavioural stimulation. The hyperthermic and behavioural responses of both agents were reduced by the 5-hydroxytryptamine (5-HT) uptake inhibitor, fluoxetine, potentiated by the monoamine oxidase inhibitor, pheniprazine, and unaltered by the dopaminergic antagonist, haloperidol. Pretreatment with the 5-hydroxytryptaminergic receptor blockers cinanserin, cyproheptadine or D-2-bromolysergic acid diethylamide markedly attenuated the effects of fenfluramine but only slightly influenced the responses to PCA. Depeletion of central 5-HT stores with p-chlorophenylalanine also affected responses to fenfluramine more than responses to PCA. The tryptaminergic receptor blocker methergoline abolished both PCA-induced hyperthermia and forepaw clonus--but not behavioural stimulation--while the effects of flenfluramine were only partly reduced. We interpret these data to mean that PCA- and fenfluramine-induced drug effects have different underlying mechanisms, the PCA responses relying possibly upon tryptamine while the fenfluramine responses are 5-hydroxytryptaminergic.


Comparative study of the dopamine-sensitive adenylate cyclase in the striatum and hypothalamus of rat brain. Stimulation by dopamine of adenylate cyclase in homogenates of rat brain striatum was enhanced in the presence of ATP (0.6--3 mM) and GTP (10--100 micrometer). The stimulation by dopamine appeared to be the result of its antagonism of inhibition of adenylate cyclase by GTP or higher concentrations of ATP. Stimulation of the enzyme by dopamine was also dependent on MgCl2, and was maximal at MgCl2 concentrations of at least two fold excess over ATP. While ATP did not inhibit adenylate cyclase in homogenates of the ventral hypothalamus, GTP (10--100 micrometer) significantly stimulated it. Dopamine stimulated the adenylate cyclase in the hypothalamus. This action was blocked by chlorpromazine (10 micrometer) and phentolamine (100 micrometer) but not by an analogue of chlorpromazine having no neuroleptic activity or by propranolol (100 micrometer).


A method to estimate binding constants at variable protein concentrations. The association constants of the binding of chlorpromazine and imipramine to serum albumin at low saturation of the protein were determined by a new experimental approach with the protein concentration rather than the ligand concentration being varied. This approach is suitable for estimating binding constants in systems with one class of binding sites. In addition, the method is proposed to complement conventional binding studies of systems with two classes of binding constant with higher accuracy.


In vitro studies on the metabolic activation of the pulmonary toxin, 4-ipomeanol, by rat lung and liver microsomes. Rat lung and liver microsomes mediated the biotransformation of the pulmonary toxin, 4-ipomeanol, to an alkylating metabolite. The enzyme-mediated microsomal alkylation required NADPH and oxygen and was strongly inhibited by carbon monoxide, which indicated the participation of a cytochrome P-450-dependent monooxygenase. Other studies with inhibitors including pyrazole, piperonyl butoxide, SKF-525A, and cobaltous chloride, and with the inducers phenobarbital and 3-methylcholanthrene, also were consistent with this view. The Km for the pulmonary microsomal alkylation pathway was more than 10-fold lower than for the hepatic microsomal pathway. There was no significant enzyme-mediated covalent binding of analogs of 4-ipomeanol lacking the furan moiety, suggesting that metabolic activation of the parent compound involves oxidation of the furan ring. Reduced glutathione prevented the microsomal alkylation by 4-ipomeanol, indicating the electrophilic nature of the alkylating metabolite.


Regulation by histamine of cyclic nucleotide levels in sympathetic ganglia. An investigation has been carried out of the role of histamine H1- and H2-receptors in the control of cyclic guanosine 3':5'-monophosphate (cGMP) and cyclic adenosine 3':5'-monophosphate (cAMP) levels in blocks of bovine superior cervical ganglion. The data suggest that activation of H1-receptors is associated with cGMP accumulation and that activation of H2-receptors is associated with cGMP accumulation. Histamine increased both cGMP and cGMP levels with similar time course and concentration-response relationships. Low concentrations of the H1-receptor agonist 2-(2-aminoethyl)thiazole increased cGMP but not cAMP levels. Conversely low concentrations of the H2-receptor agonist 4-methylhistamine increased cAMP but not cGMP levels. H1-receptor antagonists blocked the histamine-induced increase in cGMP at low concentrations but blocked the cAMP increase only at substantially higher concentrations. Conversely, H2-receptor antagonists blocked the histamine-induced increased in cAMP but not cGMP. The effects of histamine on cyclic nucleotide levels did not appear to be mediated via the release of an endogenous neurotransmitter. The histamine-induced increase in cGMP appeared to be mediated through calcium: the increase in cGMP required the presence of calcium in the extracellular medium, and the calcium ionophore A23187 caused a calcium-dependent increase in cGMP. When considered with previous electrophysiological and biochemical findings in sympathetic ganglia, a correspondence can be seen: both histamine (at H1-receptors) and acetylcholine (at muscarinic receptors) raise cGMP levels and are associated with excitatory actions; both histamine (at H2- receptors) and dopamine raise cAMP levels and are associated with inhibitory actions.


Effects of antipsychotic and antianxiety drugs on the morphine abstinence syndrome in rats. The effects of representative antipsychotic and antianxiety drugs on the abstinence syndrome in morphine-dependent rats were compared. Groups of 10 to 22 male albino Sprague-Dawley rats (250-300 g) were individually implanted s.c. with either two 75-mg morphine base pellets or two placebo pellets. After 72 hr, chlorpromazine (CPZ 1,2 and 4 mg/kg), haloperidol (0.2, 0.4 and 0.8 mg/kg), thioridazine (10, 20 and 40 mg/kg), chlordiazepoxide (2,4 and 8 mg/kg), diazepam (DPM, 1, 2 and 4 mg/kg) or vehicle was injected s.c. 55 min before precipitation of abstinence with naloxone (1 mg/kg s.c.). Jumping was exacerbated by CPZ (4 mg/kg), chlordiazepoxide (4 and 8 mg/kg) and DPM (1, 2 and 4 mg/kg); haloperidol and thioridazine had no significant effect on this sign. Weight less over 1 hr was decreased by CPZ (4 mg/kg) and DPM (4 mg/kg). Wet-dog shakes were decreased by all doses of haloperidol but increased by chlordiazepoxide (8 mg/kg) and DPM (1, 2 and 4 mg/kg). CPZ (2 and 4 mg/kg) significantly increased the incidence of teeth chattering. Other abstinence signs were not affected in a dose-related manner. Although the antipsychotic agents each decrease dopamine availability at the postsynaptic receptor, this mechanism alone cannot explain their actions on individual signs of abstinence. Perhaps it is therefore time to question how modifying agents can be meaningfully compared in morphine-abstinent rats.


Action of extracellular pH on Na+ and K+ membrane currents in the giant axon of Loligo vulgaris. Voltage-clamp currents and resting membrane potential of squid giant axons have been studied at extracellular pH varying between 4 and 10. The membrane currents, analyzed according to the Hodgkin-Huxley equations, showed that sodium permeability, PNa(E), and potassium conductance gK(E), curves were shifted toward positive voltages by different amounts and slightly depressed as the external pH was lowered. Under the same conditions, taum(E) and taun(E) were found to be enhanced and shifted to a larger extent in the same direction. The rate constants alpham and alphan were shifted substantially toward positive voltages, but betam and betan changed hardly at all. The shift of the alpham(E) curve was analyzed in terms of a fixed surface charge model; it indicates that unspecific negative groups with an approximate pKa of 4.5 are located in the vicinity of sodium active sites with an average charge separation of 8 A. A similar figure is obtained for the potassium system from the shift of the alphan(E) curve.


The mechanism of lactate transport in human erythrocytes. Lactate accumulates in human erythrocytes stored at 4 degrees C in the presence of glucose. Efflux of lactate exhibits an activation energy of 22kcal/mole and is markedly stimulated with increasing medium pH. Lactate influx into erythrocytes that were depleted of intracellular lactate by incubation at 37 degrees at pH 8.0 was stimulated by decreasing medium pH. Under appropriate conditions the pH-dependent lactate flux was insensitive to 4-acet-amido-4'-isothiocyano-2,2'-disulfonic stilbene or 4,4'-diisothiocyano-2,2'-disulfonic stilbene, inhibitors of the inorganic anion channel, while, e.g., inorganic phosphate transport was fully sensitive. These experiments as well as measurements of H+ movements associated with lactate fluxes demonstrate that lactate transport takes place via a specific monocarboxylate transporter (distinct from the inorganic ion channel) by a H+-lactate symport mechanism.


Characterization of Rauscher murine leukemia virus envelope glycoprotein receptor in membranes from murine fibroblasts. Plasma membrane preparations from KA31 (mouse) cells contained receptors for the binding of Rauscher murine leukemia virus (R-MuLV) envelope glycoprotein, gp70. This binding was demonstrated by gel filtration of a mixture of the microsomal fraction of the cells and 125I-labeled gp70. A rapid and convenient assay was developed to measure the complex formation between the membrane receptors and gp70 involving specific precipitation of the complex by 3 to 4% polyethylene glycol. The complex formation was responsive to the concentrations of both the receptor and gp70 and also to changes in temperature and pH. The gp70 binding was a noncooperative, saturable process, and an association constant of 3.5 X 10(8) M-1 was estimated from the binding data. The complex formation was reversible and a near-total exchange of 125I-labeled gp70 in the complex was achieved by incubation with excess of unlabeled gp70. The complex formation was inhibited by protein denaturing agents, guanidine-hydrochloride and urea. Pretreatment of the membrane fractions with either chymotrypsin or phospholipase C led to a loss of the membrane-associated receptor activity, indicating that a lipoprotein structure was important for the receptor function, consistent with the observation that nonionic detergents strongly inhibited the complex formation.


The pH of prostatic fluid: a reappraisal and therapeutic implications. A basic assumption in all experiments on prostatic physiology, particularly those designed to study the diffusion of drugs into the prostate gland, is that the pH of human prostatic fluid is similar to that of the dog, that is pH 6.1 to 6.5. We believe that this assumption is incorrect. Our data indicate 1) the expressed prostatic secretion of most normal men is alkaline (mean pH 7.31), 2) with prostatic infection the pH of prostatic fluid increases markedly (mean pH 8.34) and, therefore, drugs shown to diffuse into the canine prostate may be ineffective in treating prostatitis in humans and 3) the increase in pH of the expressed prostatic secretion seen with infection is not simply owing to an increase in the relative concentration of alkaline seminal vesicular components. Biochemical markers of seminal vesicular activity (fructose and prostaglandins) showed no correlation with pH values of expressed prostatic secretion. Hence, it appears that the change in pH of the expressed secretion is owing to a real increase in pH of prostatic fluid. The clinical implications of these findings are discussed. An appreciation of the profound variation in the prostatic fluid pH may be of importance not only in furthering the understanding and treatment of chronic bacterial prostatitis but, also, of other prostatic diseases as well.


Spontaneous perirenal hematoma: a complication of polyarteritis nodosa. Polyarteritis nodosa is a rare cause of perirenal hematoma owing to rupture of 1 of the aneurysms. Eleven cases have been reported previously in the English literature, including 5 with a preoperative angiographic diagnosis. Our case, which was diagnosed angiographically before a successful conservative operation, is the first report of a patient who survived 3 years. The pathology is discussed.


Hypotensive and vascular effects of labetalol in the normotensive rat and dog. A new antihypertensive agent, labetalol, has potent hypotensive effects in the anesthetized rat and dog when given intravenously and also in the unanesthetized beagle when given orally. Labetalol slightly increased renal blood flow of the anesthetized dog while decreasing blood pressure. Labetalol slightly increased blood flow of canine femoral artery under constant pressure perfusion. However as compared with hydralazine, labetalol seems to have no marked vasodilatatory effect which accounts for its hypotensive effect. Pharmacologically, labetalol possessed both alpha- and beta-blocking activities, though weaker than phentolamine and propranolol respectively. Another specific action of labetalol was that it has stronger beta-blocking action on beta1 receptor (heart rate response) than on beta2 receptor (blood pressure response). Like several other beta-blockers, labetalol seems to block neuronal uptake of noradrenaline.


Antimycobacterial activity of lecithin-cholesterol liposomes in the presence of phospholipase A2. Tubercle bacilli were preincubated with lecithin-cholesterol liposomes to be subsequently exposed to phospholipase A2. After further incubation in the environment of acidic buffer, viable units in the final mixture were enumerated by inoculating the serial dilutions of an aliquot onto Kirchner agar medium containing horse serum in 5%. Another aliquot was used for lipid analyses to confirm hydrolysis of lecithin. In addition to this bactericidal type of experiments, bacteriostatic tests were also conducted with Kirchner semi-solid agar medium, into which liposome-treated bacilli were inoculated with the enzyme at a time. Various natural and synthetic lecithins different in constituent fatty acids were employed. The results indicated that toxic fatty acids released from lecithin acted to kill the bacilli or to inhibit their growth.


Purification of a nontoxic phospholipase A2 from the venom of Indian krait (Bungarus caeruleus). A nontoxic phospholipase A2 was purified from the venom of Indian krait (Bungarus caeruleus) by a four-step procedure involving electrophoresis, gel filtration and ion-exchange chromatography. The recovery of the enzyme activity was 37% and the purified preparation was 38 times as active as the crude venom. The purified enzyme had a molecular weight of 12,500 and the optimum pH of 7.2. The enzyme showed higher specificity toward phosphatidylethanolamine than phosphatidylcholine. The preparation was not very labile to heat and its activity was dependent on the presence of divalent cations, calcium ions being the most effective activators. The enzyme was completely inhibited by iodoacetic acid but showed high stability against 8 M urea. Purified phospholipase A2 was nontoxic at an iv dose of 5 microgram/g mouse. The high specific activity, the high yield and the nontoxic nature of the enzyme indicate that the major form of phospholipase A2 in Bungarus caeruleus venom is not associated with any toxicity and has properties somewhat similar to that of phospholipase A2 from some other venoms.


Relationship between gastric secretion and serum gastrin levels in dogs anesthetized with morphine and urethane. The serum levels of immunoreactive gastrin (IRG) and secretion of gastric juice were simultaneously determined in dogs anesthetized with morphine and urethane. There was a significant positive linear correlation between secretion and serum IRG level in these dogs. Serum IRG level and gastric secretion were reduced by bilateral vagotomy at the neck. The amount of gastric juice was reduced dose-dependently by an intravenous injection of atropine (0.001--0.016 mg/kg), hexamethonium (0.064--1 mg/kg) and secretin (2--8 U/kg). The reduction of gastric secretion paralleled that of the serum IRG level. However, the reduction of gastric secretion did not parallel that of serum IRG level under the influence of prostaglandin E1 (0.002--0.008 mg/kg i.v.) and duodenal acidification. Prostaglandin E1 and duodenal acidification reduced gastric secretion without the reducing serum IRG level. These findings were discussed in relation to the mechanism of gastric juice stimulation by morphine, and it is suggested that endogenous gastrin release through the vagal and non-vagal pathways participates in morphine-induced gastric secretion. The difference in inhibitory effect between duodenal acidification and secretin suggests the possibility that substances other than secretin may participate in the regulation of gastric secretion in dogs.


Antiarrhythmic effect of oxprenolol on halothane-epinephrine and coronary ligation induced ventricular arrhythmias in beagle dogs. Antiarrhythmic effects of oxprenolol, a beta-blocker, were studied quantitatively on arhythmias produced by epinephrine during halothane anesthesia and by two-stage coronary ligation, and were compared to those of other beta-blockers, propranolol and Kö 1400, which have been already reported. Though oxprenolol has potent beta-blocking activity, the antiarrhythmic effect on halothane-epinephrine arrhythmia was significantly weaker than those of propranolol and Kö 1400. The effective dose of oxprenolol was 60 +/- 18 microgram/kg (mean +/- S.E., N = 6), which is in the range of the so-called beta-adrenergic blocking dose. The weaker antiarrhythmic effect of oxprenolol as compared to propranolol and Kö 1400 is probably due to the intrinsic positive chronotropic effect, which is most clearly observed in oxprenolol as compared to the other two drugs. As for two-stage coronary ligation arrhythmia, oxprenolol suppressed only that observed 48 hours after coronary ligation using higher doses (5 to 10 mg/kg). Other beta-blockers also showed similar effects. Because of the high doses necessary for the antiarrhythmic effects on the coronary ligation arrhythmia, the mechanism for suppressing the arrhythmia is probably due to the local anesthetic action of the beta-blockers.


Cardiovascular actions of optical isomers of propranolol. Effects of the optical isomers of propranolol on blood pressure in the rat, and in the spinal rat during adrenaline infusion were studied to investigate the mechanism of the pressor action of propranolol. Both isomers of propranolol produced a sustained pressor action in the rat and in the spinal rat infused with adrenaline. The magnitude of the pressor action produced by the d- and 1-propranolol was proportional to their beta-adrenoceptor blocking activities in the heart as was reported by several investigators. It is concluded that the pressor action of propranolol is due to the blockade of the beta-adrenoceptors mediating vasodilation in the skeletal muscle vascular beds.


[Pharmaco-kinetic aspects of protein-binding (author's transl)]. Binding of drugs to plasma proteins will influence distribution and elimination especially if factors interfere altering the extent of binding. These factors are: dependence on species, age, H+-concentration, speed of i.v. injection or the interaction of another drug for instance. Considering the quantitative aspects changes in binding to the plasma proteins will turn only then relevant to drug action if the extent of alteration is very large or the drugs are bound to a very high degree. But the scene changes completely if the binding to other proteins of the organism is considered. Experimental results concerning the binding of drugs to hemoglobin and muscle tissue suggest that this kind of binding is possibly more effective in pharmacokinetics than binding to plasma proteins.


Organotoxic effects of excessive doses of sodium nitroprusside in the rabbit. The simultaneous iv. infusion in conscious rabbits of 7.5 mg/kg.h sodium nitroprusside (SNP) plus sodium thiosulfate in the molar ratios 1:5 or 1:10, respectively, for 4 h produced perilobular necroses of liver cells. 21 days after the infusion, regeneration of the damaged cells was complete. No histological changes were found in various other organs after this high dose of SNP. No signs of liver toxicity were found in rabbits that had received 0.75 mg/kg.h SNP for 8 h daily during a period of 5 consecutive days. This dose was in the range of SNP doses recommended for clinical use in human patients. Nevertheless we suggest that apart from the thiocyanate plasma levels, also the GOT, GPT, and gamma-GT concentrations in blood be controlled, especially when high doses of SNP are to be given for prolonged periods in order to exclude possible hepatotoxic effects of SNP.


Compounds in the urinary pH 1 extract reacting with corticosteroid and tetrahydrocorticosteroid antisera. Separation of a nonpolar substance with affinity to a tetrahydroaldosterone antiserum. In human urinary pH 1 extracts prepared for the aldosterone-18-glucuronide estimation, several other substances are present, crossreacting not only with aldosterone antisera, but also with various corticosteroid and tetrahydrocorticosteroid antisera. Aldosterone was measured before and after chromatographic purification. Further characterization of the non-aldosterone immunoreactive material was made by immunological analysis of paper chromatogram eluats. Pregnancy, and administration of ACTH, dexamethasone, and metopirone led to a change of excretion in the antigenic equivalents. A method for the separation of the antigenic material is described. For structural elucidation the gaschromatography-mass spectrometry (GC-MS) method was applied.


Effects of beta-adrenergic blocking agents on peripheral vascular resistance. The effects of the beta-adrenergic blocking agents propranolol, pindolol, atenolol, bunitrolol, and methypranol on the vascular resistance of isolated perfused hindlimbs of rats were investigated. At concentrations of 0.01 microgram/ml in the perfusate dl-propranolol and pindolol significantly increased vascular resistance by blockade of beta2-receptor mediated vasodilatation, whereas atenolol, bunitrolol and methypranol had no effect on peripheral resistance at this concentration. With increasing concentrations up to 10 microgram/ml all drugs, with the exception of atenolol, caused vasodilatation. We conclude that the specificity of beta-blocking agents can be established in the isolated perfused hindlimb vasculature of rats through its effect on vascular resistance. The lack of inhibition of vascular beta2-receptors at low concentrations of atenolol and also bunitrolol and methypranol show relative selectivity for beta1-receptors. The differential effects of beta-adrenergic agents on vascular resistance may have significance for the clinical use of the drugs.


Humoral and neurohormonal aspects of blood pressure regulation: focus on angiotensin. Angiotensin circulates in the blood as a hormone. Its main target organs are vascular smooth muscle, adrenal gland and the kidney. Hormonal angiotensin increases blood pressure by its vasoconstrictor action, by stimulation of aldosterone secretion and subsequent sodium and water retention, and by the stimulation of catecholamine release. Circulating plasma angiotensin also effects brain mechanisms of blood pressure regulation. In addition to this hormonal function, angiotensin is present in the brain as part of an endogenous brain renin-angiotensin system. Brain angiotensin is not secreted into the blood and can be considered a neurohormone with local function. A role of brain angiotensin in the maintenance of high blood pressure of spontaneously hypertensive rats has been demonstrated. Circulating plasma angiotensin appears to influence brain renin levels and vice versa. Stimulation of specific areas in the brain known to be involved in the regulation of the cardiovascular system, stimulate renin secretion from the kidney. The renin-angiotensin system can therefore serve as an example for the intimate interrelationship between humoral and neurohumoral mechanisms of blood pressure regulation.


The isolation of carbon dioxide-requiring (carboxyphillic) type 19 pneumococcus (Streptococcus pneumoniae) from diseased guinea-pigs. Type 19 pneumococcus was isolated only in anaerobic cultures from tissue fluids of guinea-pigs suffering from exudative pericarditis and pleuropneumonia. The organism was pathogenic to mice even after 40 subcultures. Further study showed it to be carboxyphilic rather than anaerobic. The necessity of specifying various atmospheric conditions in the diagnostic bacteriological isolation routine is emphasized.


Isolation and partial characterization of human erythrocyte membrane NADH: (acceptor) oxidoreductase. The NADH: (acceptor) oxidoreductase (EC 1.6.99.3) was isolated from human erythrocyte ghosts by a procedure including Triton X-100 solubilization, affinity chromatography on an NAD+-Sepharose 4B column, ammonium sulfate precipitation, and isoelectric focusing. This enzyme preparation was characterized by a single band on the urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by a single precipitin line with its corresponding antiserum on double diffusion and immunoelectrophoresis. A 103-fold purification indicates that the oxidoreductase represents approximately 1% of the ghost protein mass. The specific activity of the purified enzyme was 112 units/mg protein. The pH optimum was 6.8 and the isoelectric point, pI, was 6.6 The oxidoreductase has a specificity for NADH as a cofactor. The NADPH was ineffective as a reducing agent. The enzyme activity was strongly temperature-dependent, displaying maximal activity between 35 and 40 degrees C. The energy of activation was 4.9 kcal. The enzyme activity was inhibited by sulfhydryl reagents, anionic detergents, and divalent ions. The amino acid composition of the purified enzyme is characterized by the presence of all common amino acids including half-cystine and tryptophan. The results of carbohydrate and lipid analyses indicated that the oxidoreductase is a glycolipoprotein with fucose, galactose, mannose, and glucosamine as the sugar components and cholesterol and sphingomyelin as the lipid constituents. The apparent subunit molecular weight estimated by urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the absence and presence of 2-mercaptoethanol was 40,000. The antiserum completely inhibited the enzymic activity at the equivalence point. We suggest that the membrane-bound NADH: (acceptor) oxidoreductase might be a transmembrane protein.


Phosphorylation and dephosphorylation of spectrin. The phosphorylation of spectrin polypeptide 2 is thought to be involved in the metabolically dependent regulation of red cell shape and deformability. Spectrin phosphorylation is not affected by cAMP. The reaction in isolated membranes resembles the cAMP-independent, salt-stimulated phosphorylation of an exogenous substrate, casein, by enzyme(s) present both in isolated membranes and cytoplasmic extracts. Spectrin kinase is selectively eluted from membranes by 0.5 M NaCl and co-fractionates with eluted casein kinase. Phosphorylation of band 3 in the membrane is inhibited by salt, but the band 3 kinase is otherwise indistinguishable operationally from spectrin kinase. The membrane-bound casein (spectrin) kinase is not eluted efficiently with spectrin at low ionic strength; about 80% of the activity is apparently bound at sites (perhaps on or near band 3) other than spectrin. Partitioning of casein kinase between cytoplasm and membrane is metabolically dependent; the proportion of casein kinase on the membrane can range from 25% to 75%, but for fresh cells is normally about 40%. Dephosphorylation of phosphorylated spectrin has not been studied intensively. Slow release of 32Pi from [32P] spectrin on the membrane can be demonstrated, but phosphatase activity measured against solubilized [32P] spectrin is concentrated in the cytoplasm. The crude cytoplasmic phosphospectrin phosphatase is inhibited by various anions--notably, ATP and 2,3-DPG at physiological concentrations. Regulation of spectrin phosphorylation in intact cells has not been studied. We speculate that spectrin phosphorylation state may be regulated 1) by metabolic intermediates and other internal chemical signals that modulate kinase and phosphatase activities per se or determine their intracellular localization and 2) by membrane deformation that alters enzyme-spectrin interaction locally. Progress in the isolation and characterization of spectrin kinase and phosphospectrin phosphatase should lead to the resolution of major questions raised by previous work: the relationships between membrane-bound and cytoplasmic forms of the enzymes, the nature of their physical interactions with the membrane, and the regulation of their activities in defined cell-free systems.


Primary hyperparathyroidism with multiple parathyroid gland enlargement: review of 53 cases. Of 53 patients who had hyperparathyroidism assocated with multiple parathyroid gland enlargement, 39 (74%) had primary hyperparathyroidism without clinical or laboratory evidence of associated endocrine gland dysfunction, 2 had documented familial primary hyperparathyroidism, and 12 had hyperparathyroidism as part of the multiple endocrine neoplasia syndrome. When last studied, 31 of the 39 patients with nonfamilial hyperparathyroidism had normal serum calcium levels, 3 had permanent hypoparathyroidism, 2 had recurrent hyperparathyroidism, and 3 were lost to follow-up. The two patients with familial hyperparathyroidism were treated by removal only of enlarged parathyroid glands, and in each, hyperparathyroidism recurred. Five patients with multiple endocrine neoplasia, type 1, were treated by removal only of enlarged parathyroid glands, and hyperparathyroidism recurred in four. Four patients with multiple endocrine neoplasia, type 1, were treated by removal of three or more parathyroid glands, and there were no instances of recurrent hyperparathyroidism. In one patient, permanent hypoparathyroidism developed. Three patients with multiple endocrine neoplasia syndrome, type 2, had total parathyroidectomies as a part of thyroidectomy for medullary thyroid carcinoma. In each patient, permanent hypoparathyroidism developed. When primary hyperparathyroidism occurs in the absence of a definite history of polyendocrine or familial disease, only the glands that are definitely enlarged should be removed, and normal-appearing glands should be tagged rather than risk the possibility of permanent hypoparathyroidism that may attend routine subtotal parathyroid gland excision.


Metabolic rates and intercellular transfer of molecules in cultures of human glia and glioma cells. Metabolic rates and intercellular transfer of metabolites were studied in human glia and glioma culture cells via topographic scan of NAD(P)H fluorescence by multichannel microfluorometry in conjunction with microinjection of glucose-6-P + allosteric activators. Metabolic rates evaluated from NAD(P) in equilibrium NAD(P)H transients and the required substrate levels were 3--4 times lower in glioma  cells as compared to glia cells. Both glia and glioma cells showed variability in the occurrence of intercellular metabolite transfer, detectable via observation of a transient in a neighbour of the cell injected with substrate. On this basis "multicellular integrated states" can be defined in clusters of glioma and glia cells interconnected by cell-to-cell contact and a mesh-like network of intercellular processes. Such multicellular steady states and the associated metabolic rates or their impairment can be used in turn to classify different culture lines in reference to cell physiology and pathology.


The masquerade of vasculitis: head and neck diagnosis and management. Wegener's granulomatosis and forms of giant cell arteritis result from vasculitis and masquerade with symptoms of common head and neck disease entities. Recognition of the manifestations of vasculitis can be made early in the disease course and confirmed pathologically, allowing effective therapy. Current therapy of Wegener's granulomatosis with Cytoxin and Imuran and steroids for giant cell arteritis frequently results in reversal of head and neck involvement, prevention of systemic disease, and prolonged survival.


Metabolism of cortisol by human thrombocytes. A study was made in order to see whether human thrombocytes are capable to metabolize cortisol. Known concentrations of thrombocytes were incubated with 1.23H-cortisol and the products isolated and identified by t.l.c., paper chromatography, and derivations. Two metabolites were found to be produced by thrombocytes: 20beta-hydroxycortisol and tetrahydrocortisol. The enzymatic nature of the reactions was proved by (1) heat treatment (2) finding out NADPH to be a specific cofactor and (3) the dependence of the activity on the number of thrombocytes in suspensions.


The influence of pH on starch hydrolysis by neutrophilic and acidophilic streptomycetes. The effect of pH on the starch hydrolysing activity of one neutrophilic and two acidophilic soil streptomycetes was studied in detail. The neutrophilic culture extract was active from pH 5.0 to pH 8.0, with optimum activity from pH 5.5 to 6.5. Acidophile activity occurred from pH 2.5 to 7.0 with an optimum at pH 4.0 to 4.5. After storage for 24 h at different pH levels, neutrophiles showed a sharp reduction in activity at pH 5.0 with none below this point; some activity was maintained up to pH 10.0. Acidophiles remained active after storage at pH 3.0 and retained some activity up to pH 7,0--9.0. Less detailed tests on a range of soil streptomycetes showed that the differences between acidophiles and neutrophiles were consistent. The results indicated that acidophilic streptomycetes may produce a range of exo-enzymes which are themselves acid-requiring and play an important part in decomposition processes in acidic soils and litters.


Prevalence of alcoholism in a Sydney Teaching Hospital: some aspects. This paper presents some preliminary findings from an epidemiological study of inpatients in Royal Prince Alfred Hospital in 1977. The sample included 457 patients. Of these, 15% were found to have alcohol-related reasons for admission to hospital, and 33% had concomitant alcohol problems. The drinking habits of 30% of males and 9% of females placed them at risk. Some commonly used laboratory tests are evaluated.


Studies on the glycosidases of semen: purification and properties of alpha-D-mannopyranosidase from goat seminal plasma. Alpha D-mannosidase activity in goat semen was observed to be distributed in sperm and seminal plasma. In sperm the enzyme, present in soluble and bound forms, was located within the acrosome. The bound enzyme was associated with the denuded sperm. Seminal plasma alpha-mannosidase was purified 100-fold and the final preparation was shown to be homogeneous by polyacrylamide and SDS gel electrophoresis and on isoelectric focusing. The molecular weight of the enzyme, determined by gel filtration and disc electrophoresis in the presence of SDS, was 220,000. The isoelectric pH was 7.42 and the amino acid composition is reported. alpha-Mannosidase catalyzed the hydrolysis of both synthetic and natural substrates. The Km of p-nitrophenyl alpha-D-mannoside and alpha-methyl D-mannoside were 0.695 mM and 71.9 mM at pH 4.0, the optimum pH. The natural substrates were hydrolysed to varying degrees. Zn2+ was not essential though it activated the enzyme activity over longer incubations. The enzyme was observed to be more stable at wider pH range in the presence of Zn2+ than in its absence. EDTA which did not affect the enzyme activity has effect on enzyme stability similar to Zn.2+ Seminal alpha-mannosidase is not a zinc metalloenzyme but is activated by Zn2+.


Binding interactions of glycoproteins with lectins. Since plant lectins were used to help define differences between normal and transformed cell surfaces (reviewed in References 1-4), they have been employed in many other situations where their sugar-recognition specificities could be used to advantage. One of these applications has been the purification and characterization of enzymes and other proteins; this work is reviewed here in order to define some of the variables that affect binding of glycoproteins to lectins, as well as to demonstrate how this technique has been profitably exploited for isolation of purified glycoproteins, and for their better understanding.


[Drug interactions].

[Drug interactions]. Every alteration of the effect of a drug within the human body due to substances introduced from outside are considered drug interactions. Several types of these mutual actions are differentiated. They can be influenced with varying success according to the site of the interaction. An unusual variant of the interactions sometimes appears in genetically induced disturbances in the metabolism of drugs.


The treatment of threatened premature labor by betamimetic drugs: a comparison of fenoterol and ritodrine. Studies have shown that, in patients with threatened premature labor, fenoterol and ritodrine are effective agents for delaying its onset. However, the side-effects of these drugs can be a problem. Among 133 patients studied, the intravenous administration of either agent caused marked tachycardia (but no changes in blood pressure) and a high incidence of palpitations, trembling, and nausea. During oral therapy, subjective symptoms were less frequent. The addition of the calcium antagonist, iproveratril, to the therapeutic regimen did not influence the effectiveness of the 2 agents or the incidence of their adverse side-effects.


Acid-base determinations in amniotic fluid and blood of normal late pregnancy. Amniotic fluid (AF) and arterial blood were obtained almost simultaneously from 59 healthy third-trimester pregnant women. Oxygen and carbon dioxide tensions (Po2, Pco2), pH, bicarbonate (Bicarb), total carbon dioxide (TCO2), lactate (L), and pyruvate (P) concentrations were measured. Only AF-Bicarb, AF-TCO2, AF-pH, and AF-P showed a statistically significant correlation, negative, with gestational age. AF-Po2, AF-pH, AF-Bicarb, and AF-TCO2, were lower, and AF-Pco2 was higher than in maternal blood. Amniotic fluid lactate was about 6 times, and AF-P was 2 times higher than maternal blood levels. The latter, the low bicarbonate, and the high Pco2 all contributed to the acidic pH of AF. Amniotic fluid pH was affected by fetal and maternal variables, notably maternal pH. There was no correlation between AF-Po2 and Pao2 (arterial oxygen tension), between AF-Pco2 and Paco2 (arterial carbon dioxide tension), or between AF-L and blood L. AF-Po2, AF-Pco2, and AF-L may correlate better with the intrauterine fetal status than AF-pH. Normal values obtained in this study should be useful as a baseline to monitor changes in the intrauterine environment in abnormal prgenancies.


Analysis of the use of Dycal with gutta-percha points as an endodontic filling technique. The use of Dycal combined with gutta-percha cones as a permanent root canal filling material was analyzed. The following experiments were performed: 1. In vitro microscopic analysis of Dycal's adaptation in the dentin wall--gutta-percha cone interphase. 2. Study of the duration period of alkalinity. 3. Clinical and radiograhic posttreatment, inspection and evaluation, and follow-up. The results obtained in these studies showed: 1. There was correct adaptation and adherence of the material. 2. The alkalinity persisted up to 8 months after mixing. 3. There was clinically good postoperative tolerance. 4. Clinical and radiographic success was found in 90 percent of the cases in the treatment of normal vital pulps, vital inflamed pulps, and pulpless teeth with or without areas.


Acute suppurative parotitis caused by anaerobic bacteria: report of two cases. Staphylococcus aureus is the predominant pathogen in acute suppurative parotitis. Although anaerobic bacteria are prevalent in the normal oral and upper respiratory tract flora and frequently are involved in oral and facial infections, they have seldom been isolated from patients with suppurative parotitis. It may be that a role for anaerobes in parotitis has not been documented because of inadequate specimen transport or anaerobic culture techniques. We describe two cases of acute suppurative parotitis in which cultures yielded anaerobic bacteria. In one case, no aerobes were isolated; in the other, the anaerobe was the predominant organism numerically.


Impaired distal nephron acidification in chronically phosphate depleted rats. Renal tubular bicarbonate reabsorption and acidification were evaluated in phosphate depleted rats (PD) and controls. After 33 days of phosphate depletion, urine pH of PD rats (N = 5, 5.36 +/- 0.15) was significantly higher than control (N = 5, 5.64 +/- 0.09, P less than 0.005) following an NH4Cl load. Urinary titratable acid of PD rats (9.6 +/- 1.8) was significantly reduced compared to control (117.2 +/- 19.7 muEq/3 h, P less than 0.001), whereas NH+4 excretion was not different. The plasma HCO-3 thresholds at which bicarbonaturia occurred (approximately 25 mEq/l) were identical in controls and phosphate depleted rats during isotonic bicarbonate infusion. The higher urine pH of phosphate depleted rats following NH4Cl administration was not due to low urinary phosphate as 3-day phosphate depleted rats could normally acidify urine after NH4Cl (pH = 5.86 +/- 0.09, N = 6 vs. control 5.87 +/- 0.08, N = 6, P = N.S.) despite urinary phosphate excretion as low as in 33-day PD rats. These data indicate the presence of impaired distal tubular acidification in chronically phosphate depleted rats.


Time course of changes of extracellular H+ and K+ activities during and after direct electrical stimulation of the brain cortex. The kinetics of H+ and K+ activities were recorded during and after direct electrical activation of the brain cortex (cat). H+ activity was measured with H+-sensitive glass microelectrodes (tip diameters of 1--4 micron) and K+ activity was registered with double-barrelled ion-sensitive microelectrodes (tip diameters of 1--3 micron). It could be shown that extracellular H+ activity initially decreased for a few seconds and increased only after the 7.s. Maximum acidosis was always noticed after stimulation ended. Alkalotic as well as acidotic changes were the higher the stronger the stimulation parameters were. K+ activity increased very rapidly after stimulation began, reached its maximum when stimulation ended and then decreased to its initial value with an undershoot. It is concluded that the functional hyperemia of microflow could be triggered by the rapid increase in K+ activity, whereas the initial alkalotic change of extracellular pH means that H+ activity does not play a role in the first phase of this kind of hyperemia. The alkalotic shift is interpreted to be caused by the washout of C02 due to the rapid increase in microflow. In the further course, H+ activity obviously contributes to the maintenance of functional hyperemia. In this later period K+ activity is always below the control value.


Hyperbilirubinemic and cholestatic syndromes. New concepts aiding recognition and management. An elevated bilirubin level can be classified as hyperbilirubinemia only if results of all other liver function tests are normal. In contrast, cholestatic syndromes are characterized by elevations in various measurements of liver function, particularly alkaline phosphatase, bile acid, gammaglutamyl transferase, and 5'-nucleotidase.


Localization of the site of adenylylation of glutamine synthetase by electron microscopy of an enzyme-antibody complex. Antibodies to the nucleosidel,N(6)-ethenoadenosine have been used to localize the site of adenylylation of the glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2] of Escherichia coli. Antibodies were induced in rabbits by injection of a bovine albumin-ethenoadenosine conjugate. The resulting antisera strongly bound ethenoadenosine, its 5'-nucleotide, or protein conjugates of the nucleoside; little or no crossreaction was seen to adenosine, AMP, or the protein carrier. Ethenoadenylylated glutamine synthetase was prepared by modification of the enzyme by the E. coli adenylyltransferase, using etheno-ATP as a substrate. The ethenoadenylylated glutamine synthetase was precipitated by antibodies to ethenoadenosine in conjunction with goat anti-rabbit gamma globulin. Electron micrographs of reaction mixtures of ethenoadenylylated glutamine synthetase and anti-ethenoadenosine showed individual enzyme molecules complexed with one or more antibodies and pairs of enzyme molecules crosslinked by a single antibody. The approximate site of adenylylation was located from the apparent area of contact between enzyme and antibody. We conclude that the adenylylation sites are on the periphery of the bilayered hexagonal disc, offset by 15 +/- 10 degrees from the 2-fold axis of symmetry through a vertex of the hexagon and 20 +/- 10 A from the plane between the layers of the disc.


Selective labeling of serotonin receptors by d-[3H]lysergic acid diethylamide in calf caudate. Since it was known that d-lysergic acid diethylamide (LSD) affected catecholaminergic as well as serotoninergic neurons, the objective in this study was to enhance the selectivity of [3H]LSD binding to serotonin receptors in vitro by using crude homogenates of calf caudate. In the presence of a combination of 50 nM each of phentolamine (added to preclude the binding of [3H]LSD to alpha-adrenoceptors), apomorphine, and spiperone (added to preclude the binding of [3H]LSD to dopamine receptors), it was found by Scatchard analysis that the total number of [3H]LSD sites went down to 300 fmol/mg, compared to 1100 fmol/mg in the absence of the catecholamine-blocking drugs. The IC50 values (concentrations to inhibit binding by 50%) for various drugs were tested on the binding of [3H]LSD in the presence of 50 nM each of apomorphine (A), phentolamine (P) and spiperone (S). With this combination, the IC50 for serotonin was 35 nM (compared to 1000 nM without it), indicating that [3H]LSD had become considerably more selectively displaceable by serotonin under these conditions whereas the effects of norepinephrine and dopamine on [3H]LSD binding were eliminated. Various ergots had approximately equal IC50 values against [3H]serotonin and [3H]LSD but tryptamines were much more selective against [3H]serotonin; the data may indicate the existence of the two types of serotonin receptors.


gamma-Aminobutyric acid: a neurotransmitter candidate for cone horizontal cells of the catfish retina. In the catfish retina, horizontal cells that receive inputs exclusively from red-sensitive cones are the only neurons that accumulate exogenous gamma-aminobutyric acid under our experimental conditions. When isolated eyecups are perfused with bicuculline methochloride, an antagonist of postsynaptic gamma-aminobutyric acid receptors, responses of cone photoreceptors to a field of light (3 mm in diameter) become much slower and approach those to a small spot of light (0.3 mm). In addition, bicuculline methochloride decreases the frequency responses of cone horizontal cells to a field of light. These findings indicate that, in the catfish retina, feedback synapses from cone horizontal cells to cones are chemically mediated and may use gamma-aminobutyric acid as a neurotransmitter. Our results also confirm the hypothesis that, in the catfish retina, a function of the negative feedback is to improve the frequency responses of the system.


Competitive inhibition of benzodiazepine binding by fractions from porcine brain. Fractions of porcine cerebral cortex extract separated by molecular weight on a Sephadex G-75 column were tested for their activities and potencies to inhibit [3H]benzodiazepine binding to rat brain homogenates. The fractions spanned molecular weights from 500 to 100,000. A potent inhibitor (benzodiazepine-competitive factor I, BCF-I) was discovered in the fraction containing substances with molecular weights from 40,000 to 70,000. Equilibrium binding studies indicated that BCF-I was a competitive inhibitor, making it a candidate as a benzodiazepine endogenous factor or profactor. BCF-I was heat stable, but trypsin digestion destroyed its activity. Another inhibitory fraction (BCF-II) was 1/5th as active as BCF-I and contained substances with molecular weights from 1000 to 2000.


Ectomycorrhizas as nutrient absorbing organs. Early work on ectomycorrhizas indicated that they were probably adapted to efficient nutrient absorption. The use of excised mycorrhizas has allowed study of their properties as absorbing organs. The factors affecting their rates of nutrient uptake are similar to those of other absorbing organs but their rates are often greater. On absorption the nutrient is primarily accumulated in the fungal layer but may be mobilized later by reactions under metabolic control. Phosphate is accumulated in particularly large quantities as polyphosphate, which probably explains the linear relations of phosphate absorption and oxygen uptake in certain conditions. Hyphal connections between the fungal sheath and the substrate are variable, and this poses problems about absorption of ions of low mobility, and about the function of surface phosphatases. The fungal sheath is dependent on the host for carbohydrate and the drain on it may be considerable.


Dendro-dendritic and reciprocal synapses in the primate motor cortex. Dendro-dendritic synapses have been observed infrequently in the deep layers of the motor cortex. The presynaptic dendrites are of a varicose type and themselves receive a considerable density of synapses both of the asymmetric and symmetrical type. The ultrastructure of the dendro-dendritic synapse itself shows the typical arrangement of presynaptic and postsynaptic membrane densities, often with presynaptic dense projections, and the membrane specialization is of the symmetrical type. There is the usual cleft containing electron-dense material between the presynaptic and postsynaptic profiles. The synaptic vesicles occur in a small cluster confined to a region close to the presynaptic membrane specialization; some of the vesicles are flattened and were shown by tilt analysis to be of the discoid type. Two examples were found of reciprocal dendro-dendritic synapses, both components being of the symmetrical type. A single axon terminal may make a synapse on to both dendrites involved in a dendro-dendritic synapse.


Gap junctions between dendrites and somata of neurons in the primate sensori-motor cortex. Gap junctions have been found infrequently between two dendrites or a dendrite and a cell soma in the deep layers of both the motor and somatic sensory cortices of the primate. At these junctions the outer leaflets of the plasma membranes of both profiles are intimately apposed with a gap of 2 nm between them which shows a structure of hexagonal subunits in tangential sections. These gap junctions occur mainly between the dendrites or dendrites and somata of large stellate cells but are also associated in some examples with a dendro-dendritic synapse and thus occur between large stellate dendrites and presynaptic dendrites; a desmosome may also occur in association with a gap junction and dendro-dendritic synapse. Gap junctions have been identified as sites of electrical transmission between cells in a number of sites and it is therefore suggested that some neurons in the sensori-motor cortex are electrotonically couples.


Some critical qualitative details of lorica construction in the type species of Calliacantha Leadbeater (Choanoflagellata). Qualitative structural details, amplifying or correcting previous accounts in the literature on this species have been compiled by means of light and/or electron microscopy of dry whole mounts, prepared in situ from freshly gathered wild material mainly from temperate sources in Denmark, Britain and south Alaska. The more important findings are summarized diagrammatically. These include elaborate and constant details of assembly at the anterior end of the lorica, combined with much greater variability at the hind end. The absence of continuity between the three anterior spines and any of the six longitudinal costae present at the front end of the lorica chamber is confirmed, but a range of conditions involving numerical reduction in costal numbers at the hind end is illustrated. The overall size range encountered in the three temperate localities listed is illustrated photographically, but the large cells characteristic of arctic sources are represented, for a qualitative purpose only, by means of a single photograph recording a specimen collected beneath sea ice in N. Alaska, a source which will be considered more fully on a later occasion.


Some further information about the abnormal membrane glycoprotein associated with malignancy. The abnormal membrane glycoprotein that we previously found to be associated with malignancy in a wide range of different tumours is present in the cell membrane as a dimer and appears to have a specific binding site for glucose.


Effects of oral pH on cigarette smoking. Permeability of nicotine across the oral mucosa had been shown to be a direct linear function of alkalinity in the oral cavity. Here, oral pH in cigarette smokers was manipulated from pH 5 to 8 by rinses with Sorenson's and McIlvaine's buffers. As a alkalinity increased, cigarette taste was perceived as stronger, more bitter, and, in some cases, more upleasant; and heart-rate accelerated slightly. Nicotine self-administration and blood pressure were not influenced. Differential absorption of nicotine and cross-adaptation of sour to bitter taste are both discussed as explanations for the results.


Brain and adrenal tyrosine hydroxylase activity after chronic footshock stress. Rats subjected to 9 daily sessions of electric footshock stress showed marked increases in tyrosine hydroxylase activity in various brain regions and in the adrenal gland. The activity of the brain enzyme was elevated in the cerebral cortex, hypothalamus, locus coeruleus and the pons-medulla indicating a widespread effect of stress throughout the brain. Anatomical specificity of the response was indicated by a greater percent increase in the locus coeruleus, a nucleus containing noradrenergic cell bodies, than in the hypothalamus, cortex and pons-medulla, areas that contain noradrenergic terminals.


Effects of anisomycin and CNS stimulants on brain catecholamine synthesis. Mice were injected with anisomycin, an inhibitor of cerebral protein synthesis; d-amphetamine, strychnine, or caffeine was administered 30 min later. Fifteen min before sacrifice at 1 or 2 hr after injection of anisomycin, 3H-tyrosine was injected intravenously, and catecholamine synthesis rates were estimated by measurement of the specific activity of 3H-tyrosine and the accumulation of 3H-norepinephrine and 3H-dopamine. Anisomycin decreased synthesis rates of catecholamines, but this effect was not significantly affected by any of the CNS stimulants. These results suggest that the recently reported reversal of anisomycin-induced amnesia by these stimulants is not due to an attenuation of brain catecholamine synthesis inhibition.


Transport of model compounds across the peritoneal membrane in the rat. The absorption into the systemic circulation of compounds administered intraperitoneally in large volumes was investigated in the rat. The influence on absorption of molecular weight, lipid-water partition coefficient (K), and dissociation constant (pKa) was studied. Nine neutral compounds ranging in molecular weight from 18 to 2 million demonstrated absorptions that decreased with increasing molecular weight. Five compounds were tested with variable lipid partition (K) values (0.001--3.3) and the absorptions increased from 57 to 96% as the K values increased. A series of nine acids and bases covering a wide range of pKa values )0.9--9.9) were investigated. For the acids, absorption increased with increasing pKa value, while for the bases absorption decreased with increasing pKa. For both groups of compounds absorption was directly related to the extent of ionization at physiologic pH. As has been documented for other biological membranes, the peritoneal membrane in the rat was found to behave in a lipoid manner. Unionized or lipid-soluble compounds are absorbed to a greater extent than ionized or lipid-insoluble compounds, and neutral compounds are absorbed in relation to their molecular weights.


Evidence for the multiplicity of products from acid-treated reduced nicotinamide adenine dinucleotide (NADH). Treatment of NADH with acid gives rise to as many as 10 products derived from breakdown of the dihydropyridine ring. These substances are neutral or cationic in character, and one or more may be carbonyls. They have been separated on a column of Dowex 1-formate and characterized spectrophotometrically. No evidence was obtained to indicate that acidification of NADH leads to formation of a dinucleotide containing a modified dihydronicotinamide moiety.


Electrophysiological examination of transmitter release in non-quantal form in the mouse diaphragm and the activity of membrane ATP-ase. The subsynaptic area of mouse diaphragm fibres was hyperpolarized by 1--2 mV during local curarization of the junctional zone in the presence of the reversible anticholinesteraze prostigmine (6 X 10(-6) M), or after treatment of the muscle with organophosphate cholinesterase inhibitor Soman. In a solution containing 5 mM K+ the mean hyperpolarization was 1.1 +/- 0.27 mV at mean resting potential--70 mV. After adding 2 X 10(-5) M ouabain the hyperpolarization increased to 1.5 +/- 0.25 mV. Removal of potassium ions from the bathing medium also increased curare induced hyperpolarization to 1.80 +/- 0.40 mV. Reactivation of membrane ATP-ase by addition of K+ after a period in K+-free medium reduced the hyperpolarization to zero, where measurements were performed 10--20 min after the readdition. It was concluded that spontaneous non-quantal leakage of acetylcholine occurs at the mouse neuromuscular junction, as it does in the frog (ref. Katz and Miledi 1977). Conditions which block the Na+-K+-dependent ATP-ase of nerve terminals increased the continuous leakage of ACh and activation of the pump decreased it.


Etonitazene as a reinforcer: oral intake of etonitazene by rhesus monkeys. Drinking of etonitazene HCI was studied in three rhesus monkeys during daily 3-h sessions. As the drug concentration was increased, the number of liquid deliveries decreased, and etonitazene intake (microgram/kg body weight) increased. As fixed-ratio (FR) requirements were increased, rate of responding increased, and liquid deliveries slightly decreased. When water was substituted for the drug, there was a large increase in responding for several sessions, followed by a slow decline to low rates. When etonitazene was reintroduced, responding abruptly increased to previous drug levels. These data suggest that etonitazene can serve as a positive reinforcer when taken orally by rhesus monkeys.


Propranolol in experimentally induced stress. The beta-adrenergic receptor-blocking drug, d,l-propranolol, was compared with placebo for relief of experimentally induced anxiety. Subjects were chosen on the basis of having high levels of trait anxiety. Stress was induced experimentally by two performance tests. Single 40-mg doses of propranolol significantly slowed the heart rate, suggesting a satisfactory pharmacologic effect of the drug. The treatment was not superior to placebo, however, on any other measure. The experimental model used had clearly demonstrated an antianxiety effect of single 5-mg doses of diazepam. Propranolol at the dose used had little effect on psychic anxiety as determined by this model.


Dopaminergic supersensitivity after neuroleptics: time-course and specificity. It is known that a single dose of a neuroleptic can elicit dopaminergic supersensitivity in animals. On the other hand, the clinical syndrome of tardive dyskinesia takes many months of years to develop. To resolve this apparent discrepancy, it is possible that subclinical or latent tardive dyskinesia is fully compensated in most patients taking neuroleptics. In others, where the tardive dyskinesia is full-blown and grossly apparent, the dopaminergic supersensitivity may be decompensated. Such compensatory and decompensatory phases have been proposed earlier by Hornykiewicz (1974), in the case of Parkinson's Disease. Dopaminergic supersensitivity persists for a period proportional to the lenght of the neuroleptic treatment. It is not yet clear whether the relation between the length of treatment and the persistence of supersensitivity holds for very long treatments, but in principle the relationship might account for the persistence of tardive dyskinesia after years of neuroleptic pretreatment.