Electron and proton transport in the ubiquinone cytochrome b-c2 oxidoreductase of Rhodopseudomonas sphaeroides. Patterns of binding and inhibition by antimycin. The effect of antimycin on the ubiquinone cytochrome b-c2 (Q b-c2) oxidoreductase of the photosynthetic bacterium Rhodopseudomonas sphaeroides has been studied under controlled oxidation-reduction potential (Eh) conditions by equilibrium measurements and by rapid kinetic analysis of single turnover flash.induced electron and proton translocations. 1. Antimycin shifts the alpha-band of ferro b50 (lambda max 560 nm) by 1 to 2 nm toward the red but has no apparent effect on the equilibrium oxidation-reduction midpoint potential of the cytochrome. 2. This red shift is proportional to the antimycin added until a "titer" of 0.7 +/- 0.1 antimycin per reaction center (RC) is approached. With a similar titer antimycin essentially abolishes the following millisecond reactions activated by saturating single turnover flashes: reduction of ferri c2, oxidation of ferro b, Phase III of the membrane-potential-indicating band shift of endogenous carotenoid pigments, and the uptake of 1 of the 2 protons taken up per electron transferred. Such titrations indicate that the binding (KD approximately 10(-9) m) and mode of inhibition of antimycin are noncooperative and are independent of the membrane's coupling status and of the pH and Eb over the range in which electron transport is operative. 3. In the presence of excess antimycin a partial recovery of ferri c2 reduction is seen when the intensity of the flash is diminished, but only at Eh values such that Z (a special quinone serving as reductant for ferri c2) is reduced but b50 is oxidized before activation. These results are consistent with the following model. Each Q b-c2 oxidoreductase complex includes one antimycin binding site, one b50, and one Z. These complexes and the c2 . RC complexes, present in an 0.7:1 ratio, are to some degree mobile with respect to each other. Ferri b50 can be reduced either via the quinones of the RC or via Z in a reaction also involving c2. The former route is kinetically dominant in the presence of antimycin, but the latter route is the means for "oxidant-induced reduction" and depends on the collisional interaction of the oxidoreductase and c2 . RC complexes. Antimycin interferes with neither of these two routes but does inhibit the oxidation of ferro b50; all the other inhibitory effects are consequent on this.


On the optimization of local hyperthermy in tumors based on a new radiofrequency procedure. Local hyperthermy of large body areas using the CMT selectotherm method. A new radiofrequency procedure, i.c., the CMT Selectotherm technique, permits to convey large heat quantities per volume unit also to deep-seated tumor tissues without causing thermal lesions in healthy tissues near or at the body surface. The improved spatial homogeneity of energy supply attainable by this method is demonstrated by measurements at a gelatine phantom and, in particular, by in vivo measurements on pigs. The appliability of local hyperthermy to tumors localized in different parts of the body is substantially improved (a) by the principle of superimposing local hyperthermy on an elevated temperature level of metabolically induced whole-body hyperthermy (CMT-spontaneous hyperthermy at 40 degrees C) and (b) by the principle of selective increasing the thermal sensitivity of tumor tissues by decreasing the pH in these areas (the CMT main step). It is shown that the temperature dose T. deltat necessary for the selective occlusion of the vasculature in tumor tissues can be obtained by the CMT Selectotherm process also in deep-seated tumors. This process is part of the 1977 CMT concept. The fundamentals of optimizing local hyperthermy with consideration of heat dissipation from the tissue by heat conduction and convection via the blood stream are demonstrated. Temperature profiles are calculated for some practice-relevant, typical examples (inner and outer parts of sphero-symmetrically shaped tumors). Finally, in vivo measurements and calculations on the time course of temperature under certain conditions and for different tissue layers are discussed.


Synaptic vesicle exocytosis captured by quick freezing and correlated with quantal transmitter release. We describe the design and operation of a machine that freezes biological tissues by contact with a cold metal block, which incorporates a timing circuit that stimulates frog neuromuscular junctions in the last few milliseconds before thay are frozen. We show freeze-fracture replicas of nerve terminals frozen during transmitter discharge, which display synpatic vesicles caught in the act of exocytosis. We use 4-aminopyridine (4-AP) to increase the number of transmitter quanta discharged with each nerve impulse, and show that the number of exocytotic vesicles caught by quick-freezing increases commensurately, indicating that one vesicle undergoes exocytosis for each quantum that is discharged. We perform statistical analyses on the spatial distribution of synaptic vesicle discharge sites along the "active zones" that mark the secretory regions of these nerves, and show that individual vesicles fuse with the plasma membrane independent of one another, as expected from physiological demonstrations that quanta are discharged independently. Thus, the utility of quick-freezing as a technique to capture biological processes as evanescent as synaptic transmission has been established. An appendix describes a new capacitance method to measure freezing rates, which shows that the "temporal resolution" of our quick-freezing technique is 2 ms or better.


Specific fluorescent labeling of chicken myofibril Z-line proteins catalyzed by guinea pig liver transglutaminase. Guinea pig liver transglutaminase has been found to catalyze the covalent incorporation of dansylcadaverine into chicken skeletal muscle myofibril proteins. Epifluorescence microscopy reveals that the incorporated dansylcadaverine is specifically localized at or near the myofibril Z line. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) indicates that actin constitutes a major fraction of the labeled material; the Z-line proteins alpha-actinin and desmin also show significant labeling, as well as tropomyosin, several additional unidentified proteins, and material with an extremely high molecular weight. The Z-line-specific fluorescence can be removed by brief trypsinization, which releases fluorescent alpha-actinin into the supernate. The majority of the fluorescent protein species are resistant to extraction by either 0.6 M KCl or KI. These results, in conjunction with the microscopic localization, suggest that the dansyl-labeled proteins are constituents of the myofibril Z line. A significant amount of fluorescently labeled transglutaminase is also present in labeled myofibrils, which is resistant to extraction with either 0.6 M KCl or KI. This result indicates a strong, noncovalent interaction between the transglutaminase molecule and the myofibril Z line.


Conformational change in the outer doublet microtubules from sea urchin sperm flagella. Dark-field microscopy with a high-powered light source revealed that the outer doublet microtubules (DMTs) from sea urchin (Pseudocentrotus depressus and Hemicentrotus pulcherrimus) sperm flagella assume helically coiled configurations (Miki-Noumura, T., and R. Kamiya. 1976. Exp. Cell Res. 97: 451.). We report here that the DMTs change shape when the pH or Ca-ion concentration is changed. The DMTs assumed a left-handed helical shape with a diameter of 3.7 +/- 0.5 micron and a pitch of 2.8 +/- 0.7 micron at pH 7.4 in the presence of 0.1 mM CaCl2, 1 mM MgSO4, and 10 mM Tris-HCl. When the pH was raised to 8.3, the helical diameter and pitch decreased to 2.1 +/- 0.1 micron and 1.3 +/- 0.3 micron, respectively. This transformation was a rapid and reversible process and was completed within 1 min. Between pH 7.2 and 8.3, the DMTs assumed intermediate shapes. When the Ca-ion concentration was depleted with EGTA, the helical structure became significantly larger in both pitch and diameter. For instance, the diameter was 3.8 +/- 0.4 micron at pH 8.3 in the presence of 1 mM EGTA and 2 mM MgSO4. Using a Ca-buffer system, we obtained results which suggested that this Ca-induced transformation took place at a Ca concentration of approximately 10(-7) M. These results were highly reproducible. The conformational changes in the DMT may play some role in the bending wave form of flagellar movement.


Intracellular pH changes during the cell cycle in Tetrahymena. The equilibrium distribution of 5,5-dimethyloxazoladine 2,4-dione (DMO) between intra- and extracellular volume was used to estimate intracellular pH (pHi) in Tetrahymena pyiformis. In control experiments, DMO was found to equilibrate rapidly in response to a pH gradient. Under normal growth conditions, pHi was constant over a finite range of external pH, being maintained near pH 7.1 over the external pH range 5.2 to 7.3. This same range of external pH was also optimal for growth. pHi was monitored during the cell cycle of a synchronous population of T. pyriformis GL. The cells were synchronized either by starvation/refeeding or heat shock. Under both conditions, there were two alkaline shifts of approximately 0.4 pH units per cell cycle. These shifts in pH retained a constant remporal relationship to S phase and were not affected by changes in the time, duration, or magnitude of cytokinesis.


Cross-linking of fibronectin to collagen by blood coagulation Factor XIIIa. Soluble fibronectin is found in body fluids and media of adherent cultured cells and binds to fibrin and collagen. Insoluble fibronectin is found in tissue stroma and in extracellular matrices of cultured cells. Fibronectin is a substrate for Factor XIIIa (plasma transglutaminase) and can be cross-linked by Factor XIIIa to itself and the the alpha-chain of fibrin. We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis to investigate Factor XIIIa-mediated crosslinking of fibronectin to collagen. At O degrees or 37 degrees C, fibronectin could be cross-linked to iodinated cyanogen bromide fragment 7 of the alpha 1(I) chain. At 22 degrees or 37 degrees C, fibronectin could be cross-linked to isolated alpha 1(I) chains of type I collagen. Fibronectin could also be crosslinked to types I and III collagen, but only at 37 degrees C. alpha 1(I)-CB7, alpha 1(I) collagen chains, type I collagen, type III collagen, and fibrin all blocked cross-linking between 125I-alpha 1 (I)-CB7 and fibronectin. alpha 1(I)-CB7 blocked cross-linking between fibronectin and fibrin. These results indicate that the determinants of fibronectin-fibrin and fibronectin-collagen binding and cross-linking are similar. Cross-linking of fibronectin to collagen likely occurs in vivo and may be important for normal wound healing, collagen fibrillogenesis, and embryogenesis.


The association of bovine SH-kappa-casein at pH 7.0. The self-association of SH-kappa-casein at pH 7.0 in 0.01 M-EDTA, 0.001 M-dithiothreitol buffer, containing 0.1, 0.2, 0.5 or 1.0 M-NaCl is of a monomer-polymer type. The polymer is a spherical particle, diam. 23 nm and mol. wt 570000 (30 monomers). These parameters are not greatly influenced by variations in ionic strength above 0.1. The critical micelle concentration, which is a property of a monomer--polymer equilibrium, decreases with increasing ionic strength. The standard free energy of association is about -36 kJ/mol. monomer at 20 degrees C.


The equilibria of calcium and phosphate ions with the micellar calcium phosphate in cow's milk. Calorimetric measurements of the heat of solution of micellar Ca phosphate suggest that this material more closely resembles OH-apatite than amorphous Ca phosphate or any other crystalline form. Preliminary computer calculations of the ionic equilibria of milk salt solutions indicate that, over a wide range of pH and temperature, such solutions are supersaturated with respect to OH-apatite and to various other Ca salts under certain conditions.


Covalent bonds formed in proteins during milk sterilization: studies on caseins and casein peptides. Formation of covalent bonds at milk sterilization temperatures was studied using caseins and casein peptides. At 120 degrees C lysinoalanyl residues produced even at pH 7.0 were derived from intra-molecular interactions between phosphoserine and lysine; the conditions of formation were determined. It was also found that the formation fo isopeptidic cross-links was significant with conditions more severe than those used for milk sterilization.


Clobazam versus placebo for anxiety and tension in psychoneurotic outpatients. A multicenter collaborative study. Clobazam, a 1,5-benzodiazepine, was compared with placebo in 190 psychoneurotic outpatients with prominent symptoms of anxiety and tension of at least two weeks of duration. The design was one of double-blind parallel groups treated for one week. Clobazam subjects began on 40 mg daily in divided dosage, which was increased to 80 mg daily be day 3 if the drug was well tolerated. Two patients receiving clobazam had laboratory chemistry abnormalities which were possibly drug related. Adverse effects occurred more frequently in the clobazam group and were typical of those of marketed benzodiazepines. This study indicates that clobazam is an effective anxiolytic agent demonstrating its clinical effects during the first week of treatment.


Titrimetric studies on milk and milk products. Potentiometric acid-base titration is a simple method that can be used successfully in the investigation of the protein system of milk and other protein-containing products. Its applications include the examination of conventional heating procedures, cheese ripening, the investigation of processed cheese and the effect of melting salts. The principle depends on the performance of pH-dependent phase transitions which are recorded by a single titration cycle and evaluated quantitatively by means of hysteresis loops.


Effects of stannous fluoride and tiodonium chloride on dental plaque in rats. Rats with six-day-old plaque were treated twice daily with mouthrinses containing either tiodonium chloride, stannous fluoride or a placebo. Although the results for tiodonium chloride were unremarkable, stannous fluoride mouthrinses proved to be significantly effective in removing dental plaque and in restricting the ability of plaque to lower the pH of sugar solutions.


The effect of histamine-1 and histamine-2 antagonists on airway responses to histamine in the rhesus monkey. This study used rhesus monkeys with consistent respiratory responses to aerosolized histamine. Two systems of histamine challenge were evolved to study the effects of histamine antagonists on the histamine-induced respiratory response. One system consisted of administering increasing subreactive concentrations of histamine until an airway response (H) occurred. This threshold histamine dose was repeated (H'). The pulmonary function changes occurring with the H' challenge were less intense than those with H. M, a histamine-2 receptor antagonist, when given before the H' dose was associated with a potentiated H' response compared with the threshold H response. This provides evidence for histamine-2 receptor sites in rhesus monkey airways. A second system used duplicate histamine challenges with a known reactive dose of histamine. In this system, the pulmonary function changes occurring with the repeated challenge (H') were greater than with the first reactive challenge dose (H). This H' response was inhibited partially with diphenhydramine, a histamine-1 receptor antagonist. These two systems of histamine challenge provide an experimental model for evaluating pharmacologic alteration of histamine-induced respiratory responses. There is evidence for the existence of histamine-1 and histamine-2 receptor sites in the airways of the rhesus monkey.


Cadmium concentration and distribution in corn (Zea mays L.) grown on a calcareous soil for three years after three annual sludge applications. The disposal of digested sewage sludge on crop-producing land appeals to municipalities as an option but may pose a hazard to human and animal health if the plant material contains elevated levels of some heavy metals. This paper reports the levels of cadmium in corn grain and stover for six years -- three years with sludge applied annually and for three years after sludge applications were terminated. The cadmium concentration in corn grain from the sixth year was similar to values found in corn grown on non-sludged plots. In corn stover from treated plots the cadmium concentration was greater than from untreated plots. Our study indicated that phytotoxic levels of cadmium did not exist even though elevated levels occurred in the corn stover.


Reduction of fecal indicator bacteria in sewage effluent when pumping for crop irrigation. When sewage effluent was pumped from a lagoon for spray irrigation the pumping process reduced the fecal coliforms (FC) by 66% and the fecal streptococci (FS) by 91%. Bactericidal effects associated with the pumping of effluent were investigated in the laboratory by seeding sterilized effluent with fecal bacteria and repeatedly passing the liquid through a centrifugal impeller type pump at 50 psi pressure. The pumping effect was cumulative, 49 and 90% of FC being killed after two and four passages through the pump, respectively. FC were more susceptible than FS to injury by pressure shock. Very weak chlorination of the effluent increased the destruction of FC but not FS during subsequent pumping. Within the range of experimental conditions used, the percentage of FC killed by pumping was not markedly affected by changes in temperature and pH of the effluent or by differences in the number and age of cells added.


Biological characteristics of peptidoglycans of group A streptococcus and some other bacterial species. II. Immunological mechanisms involved in thrombocytolysis. Immunological mechanisms are involved in the thrombocytolytic activity of peptidoglycan of Group A streptococcus, Streptococcus pneumoniae and Staphylococcus aureus. Inactivation of particular components of complement (heating of blood serum to 56 degrees C,incubation with zymosan or NH4OH) inhibited the thrombocytolytic activity of group A streptococcus peptidoglycan. So did preincubation of Group A streptococcus peptidoglycan with homologous antipeptidoglycan antibody. On the other hand, antibody to Group A streptococcus peptidoglycan did not inhibit the thrombocytolytic effect of Streptococcus pneumoniae or Staphylococcus aureus peptidoglycan. Human platelets are resistant to peptidoglycans. They remain resistant in the presence of rabbit serum although rabbit platelets are highly sensitive to peptidoglycans. This suggests that, for the expression of the thrombocytolytic activity of bacterial peptidoglycan, specific receptors on the surface of platelets must be present in addition to serum factors.


Histochemical investigation of some mitochondrial and microsomal enzymes in the kidneys of rabbits immunized with type B botulinus anatoxin. Immunization of rabbits with botulinus anatoxin containing a number of proteins of bacterial origin causes a statistically significant increase in the activity of succinate dehydrogenase, NAD diaphorase and NADP diaphorase as early as after 24 hours. After 5-7 days, the activity of all mitochondrial enzymes drops below the control level and returns to normal by the 14th day. The activity of glucose 6-phosphatase decreases significantly already 24 hours after immunization and returns to normal by the end of the 7th day. The mechanism of excretion of foreign protein in the kidneys of immunized animals is discussed.


ELISA methodology for polysaccharide antigens: protein coupling of polysaccharides for adsorption to plastic tubes. A method is described which permits the adaption of ELISA techniques for measurement of antibody against bacterial polysaccharides. First, the polysaccharides antigen is covalently bound to poly-L-lysine, using cyanuric chloride as the coupling agent. The poly-L-lysine then adsorbs to the walls of plastic tubes, thus immobilizing the polysaccharide coupled to the poly-L-lysine. The method is simple, rapid, and utilizes small amounts of polysaccharide antigen.


The role of enzymatic coupling of drugs to proteins in induction of drug specific antibodies. Isoniazid and hydralazine were covalently crosslinked by epidermal transglutaminase to serum and cell nuclear proteins. Albumin and nucleohistones were excellent acceptors of these drugs in serum and nuclear extracts, respectively. Drug-albumin and drug-histone conjugates were highly antigenic in rabbits within 4 weeks, eliciting drug-specific antibodies in all immunized animals. A radioimmunoassay for antibodies to isoniazid were developed, using a standard drug-albumin conjugate. The methods described here of enzymatic crosslinking of drugs to proteins facilitate studies of drug-induced hypersensitivity in animals and man.


Allergic encephalitis, rabies antibodies, and the blood/brain barrier. Similarity of the syndromes of rabies and of encephalomyelitis resulting from rabies vaccination poses a problem in differential diagnosis that has had tragic consequences. That difficulty may also be largely responsible for the traditional belief that rabies is inexorably fatal, in that recovery from paralysis is interpreted as evidence that the disease was postvaccinal encephalomyelitis rather than rabies. Diagnosis is additionally complicated by presence of rabies antibodies in serum in both conditions. However, we have found that rabies antibodies elicited by vaccination do not pass the blood/brain barrier to enter the fluids of the CNS in EAE, the experimental counterpart of postvaccinal encephalomyelitis; whereas antibodies are present in high titer as a result of production in situ after recovery from rabies. Therefore a ratio of antibody concentrations of greater than 1:10 in CSF and serum indicates chronic rabies or recovery from that disease.


Influence of diet and metabolism on urinary acid excretion in the rat and the rabbit. Rabbits normally excrete an alkaline urine, whereas rat urine is usually acidic. This study was designed to determine whether this difference was attributable to the composition of the diet or to specific metabolism of the species. Balance studies were performed in rabbits and rats with comparable growth rates who were consuming standard laboratory feed. The diets for both species had an excess of fixed cations over anions. Rats fed Rat Chow excreted urine containing net acid, whereas rabbits fed the same diet excreted urine containing net base. Rabbits eating Rabbit Chow excreted a very alkaline urine, but rats eating the same diet excreted much less alkali when expressed per kilogram of body weight. Balance studies demonstrated that rabbits absorbed a much higher proportion of dietary organic anions and excreted a larger fraction of this as total CO2. Collecting-duct hydrogen ion secretion and ammonium excretion, which are normally low in the rabbit during metabolic acidosis, were not increased when Rat Chow was consumed by rabbits for 2 weeks. In summary, feeding identical diets to rabbits or rats led to vastly different values for NAE. There appeared to be a gastrointestinal difference, as judged by the quantity of absorbed organic anions, as well as a metabolic difference reflected in the very different ratios of urinary total CO2 to organic anion.


Immobilization of actin and myosin.

Immobilization of actin and myosin. Using glutaric dialdehyde, the muscle proteins myosin, actin, actomyosin and heavy meromyosin subfragment-1 (S-1) have been immobilized on capron fibers. The ATPase activity of myosin and its capability to interact with actin have been preserved whereas the ATPase activity of its subfragment decreased significnatly. Immobilization on capron fibers changes the pH dependence of the ATPase activity of myosin and of S-1 shifting the maximum towards the acid zone (pH 5.5) and increases the thermal stability of the enzyme. Calcium ions produce a stimulatory effect on ATPase; Mg2+ions yield no effect on myosin and S-1 but enhance the activity in the case of immobilized actomyosin though to a lesser degree than the ions of Ca2+. Immobilized actin retains its ability to form actomyosin complex.


Dissolution of rabbit zona by sperm acrosomal extract: effect of calcium (1). The acrosomal extracts from rabbit spermatozoa were more effective in dissolving the zona pellucida of the rabbit ova in the absence than in the presence of Ca2+. The extracts had high proteolytic activity but low esterolytic activity at alkaline pH in which pH effective zona hydrolysis occurred. The results suggest that acrosomal proteinases in addition to acrosin may be involved in the zona penetration.


Feedback control of pineal function by reproductive hormones--a neuroendocrine paradigm. Secretions from the pineal gland participate in the control of reproductive function. In turn gonadal steroids, gonadotrophins and prolactin modify pineal metabolic activity and change the rate of synthesis of pineal hormones. The article reviews the major observations made regarding the pineal gland and its innervating neurons as target tissues for reproductive steroid and hypophyseal hormones.


Studies on the control of pineal indole synthesis: cyclic nucleotides, adenylate cyclase and phosphodiesterase. An overview of the biochemical events that occur when postsynaptic pineal beta-adrenergic receptors are stimulated is presented. Emphasis is placed on the importance of the adenylate cyclase system for the induction of N-acetyltransferase (NAT). Super- and subsensitive responses of NAT to receptor agonists are related to cAMP concentration, adenylate cyclase and phosphodiesterase activities and receptor binding sites.


Primitive nervous systems: action of aminergic drugs and blocking agents on activity in the ventral nerve cord of the flatworm Notoplana acticola. Electrically evoked activity in the submuscular ventral longitudinal nerve cords of Notoplana acticola is depressed by GABA and glycine in the presence of high magnesium concentrations. This inhibition occurs with 0.001--0.01 millimolar concentrations of these putative aminergic neurotransmitters and is reversible when washed out. The action of GABA and glycine was reversed nonspecifically by picrotoxin, bicuculline, and strychnine. PTZ (Pentylenetetrazole) was shown to mimic the effects that these blocking agents had on evoked activity when they were tested alone. The release of inhibition by these blocking agents is similar to that of decerebration. Three possible mechanisms responsible for synaptic activity in high Mg2+ concentrations are discussed and the possibility that the effector site of interaction may be the chloride ionophore is explored.


Copper(I) complexes of penicillamine and glutathione. Equilibrium analysis of a model system for the in vivo reactions between penicillamine and Cu(I), the penicillamine-glutathione-Cu(I) system, indicates that in a certain concentration range the use of penicillamine as a drug will not disturb the normal Cu(I) metabolism. The equilibrium data required for this analysis were obtained by emf titrations on the Cu(I)-glutathione (H3A) and the Cu(I)-pencillamine (H2A) systems at 25 degrees C. in 0.5 M NaClO4 medium, using glass and copper amalgam electrodes; the data were analyzed first by various graphical methods and then by a general least squares computer program. The results show that mononuclear Cu(I) species Cu(HA)2 form in both systems with stability constants log beta 122 of 38.8 (glutathione) and 39.18 (penicillamine); in addition, the polynuclear Cu5A43- species forms in the penicillamine system and the mononuclear CuHA- species might form in the glutathione system. The results are discussed in relation to the therapeutic use of penicillamine as well as in relation to the toxic action of copper on living cells.


Blood flow and permeability changes in the immune lymphocyte transfer reaction. Blood flow (133Xe clearance) and plasma exudation ([133I]HSA) have been measured in the immune lymphocyte transfer (ILT) reaction and skin grafts in rabbits. Injection of sensitised lymphocytes produced a dose-related increase in plasma exudation and blood flow at 48 hr, reached a maximum at day 3 and faded from day 5 to 8. There was an increased blood flow and plasma exudation on day 4 after grafting autografts and homografts, but the increase in plasma exudation was significantly higher in homografts. In the ILT reaction (48 hr) and the homografts (4 days) but not in autografts, prostaglandin synthetase inhibition caused a significant reduction in the increased blood flow, but did not abolish it nor did they affect the increased plasma exudation. It is concluded that the ILT reaction is a suitable model for the study of mediators of the vascular effects of the early phase of the skin graft reaction. The present experiments suggest that the vasodilatation is partly due to prostaglandin formation, but part of the vasodilatation and all the plasma exudation are mediated by substances other than prostaglandins.


The influence of binder concentration on the bond formation of pharmaceutical granules. The formation of particle mucilage bonds with dicalcium phosphate dihydrate and starch mucilage binder reduces the B.E.T. nitrogen adsorption surface are from 196 to 0.96 m2 g-1. The maximum reduction (40%) of granule surface area at a binder concentration of 10% w/w corresponded to similar optima in friability, compressability and median granule size. Surface and pore-void structural analysis by mercury intrusion could not discriminate between pore-void sizes in the range 0.5-100 nm. Nitrogen adsorption measurements showed, however, that the microporous surface area decreased from 0.3 to 0.18 m2 g-1 as binder surface coverage increased over the concentration range 2 to 20% w/w starch mucilage.


Sources of variation during collaborative evaluation of in vitro dissolution tests for two solid preparations. Collaborative in vitro dissolution tests on a sample of commercial tolbutamide tablets and a sample of oxytetracycline capsules were carried out in eight laboratories. The two preparations tested showed differences between the products in release characteristics, particularly in the distintegration phase. This may have caused the difference in the pattern of variance in the two trials. In  the case of tolbutamine tablets the value of the repeatability standard deviation was small, and therefore the major contribution to the variance was in the difference between laboratories. With oxytetracycline capsules the major contribution of the variance lies in the random errors common to all laboratories (i.e. the within-laboratory variance). One  major source of inter-laboratory viance was identified as the level of vibration at the side of the dissolution flask. Another source of variation was found to be due to using a stated extinction coefficient instead of comparing the absorbances of the samples to those of a solution of a reference substance.


Isolation and identification of a fluorophore from ampicillin degradation. A fluorescent impurity in ampicillin has been isolated and identified as 2-hydroxy-3-phenylpyrazine. The product is formed under acidic conditions similar to those employed in some fluorometric assay procedures. The mechanism of the reaction is proposed to involve cyclization by condensation of the penilloaldehyde of ampicillin. The structure was confirmed by independent synthesis.


The detection of enzyme induction by rat liver microsomes prepared by isoelectric precipitation. A comparison was made of various indices of the hepatic drug-metabolizing apparatus associated with the postmitochondrial superntant, microsomes harvested by differential centrifugation, and microsomes harvested by isoelectric precipitation from control, phenobarbitone-pretreated and 3-methylcholanthrene-pretreated rats. The metabolic capabilities and distinctions between control and induced rats for each of the three liver preparations compared favourably as determined by the concentration of cytochrome b5 and P-450 and by the activity of NADPH-cytochrome c reductase, 4-dimethylaminoantipyrine N-demethylase and aryl hydrocarbon (benzo[a]pyrene) hydroxylase. The results suggest that the relatively simple isoelectric precipitation technique is a useful alternative to the conventional method of differential centrifugation for the preparation of hepatic microsomes.


A radioreceptor assay for benzodiazepines. A simple, rapid and sensitive radioreceptor assay for determining benzodiazepines in serum is based on the displacement by the drug of specific [3H]diazepam binding to a membrane fraction from rat brain. The limit of detection of the more active benzodiazepines is about 0.5 ng. Diazepam, nitrazepam, clobazam and HR 458 have been assayed in human serum after a single oral clinical dose. The results can be used for determining pharmacokinetic parameters. The technique measures not only the parent benzodiazepine but also clinically active metabolites.


Determination of erythrocyte membrane-buffer partition coefficients by numerical analysis of multicomponent spectra. A method suitable for the measurement of erythrocyte membrane-buffer partition coefficients by u.v.-spectrophotometry is described. This method is characterized by a proper correction for inconstant background absorption in case of bad signal to noise ratios. For this purpose the multicomponent u.v.-spectrum of a compound in the presence of absorbing materials lost by erythrocyte membranes is decomposed into its constituent spectra by means of numerical analysis. Application of this method to the determination of partition coefficients of benzhydrol, 4-bromophenol and benzyl alcohol yields satisfactory agreement with literature values for the latter two coefficients.


Analysis of the contractile effect of 5-hydroxytryptamine on the isolated posterior communicating artery of the cat. 5-Hydroxytryptamine (5-HT) induced dose-dependent increases in tension on the isolated posterior communicating artery (PCA) of the cat were significantly antagonized by lysergic acid diethylamide (LSD, 6 X 10(-9). In the presence of the phentolamine (10(-6) M) the contraction induced by the two lowest doses of 5-HT was significantly reduced. Pretreatment of the animals with reserpine (3 mg kg-1, i.p., total dose) did not modify the dose-response curve to 5-HT except for the lowest dose. Removal of both superior cervical sympathetic ganglia 15 days before the experiment brought about a significant increase in the vasoconstriction induced by 5-HT at all the doses compared with the control. Cocaine (10(-6) M) induced a significant shift to the left of the dose-response curve to 5-HT but the maximum response was the same as in the control. The augmented response to 5-HT after denervation was partially antagonized by LSD (6 X 10(-9) M) but not by phentolamine (10(-6) M). These results show that the vasoconstriction elicited by 5-HT in the PCA of the cat is mainly due to direct stimulation of tryptaminergic receptors. The participation of an indirect adrenergic component in the contractile effects of 5-HT seems to be negligible.


An in vitro study of the effects of calcium on the cardiovascular actions of thiopentone, althesin and ketamine in the rat. The actions of three intravenous anaesthetics, Althesin, thiopentone and ketamine have been compared on the rat isolated atria and portal vein. Although the three anaesthetics had grossly similar actions on the two preparations. i.e. depression of atrial rate and depression of the amplitude of myogenic activity in the portal vein, there were enough differences to suggest that they produced their effects by different mechanisms. These differences were particularly obvious in interactions with noradrenaline and the effects of changes in calcium ion concentration on the concentration effect relationships for the agents on the atria and portal vein. Generally Althesin was unaffected by changes, but in qualitatively different ways.


Role of taurine as a possible transmitter in the thermoregulatory pathways of the rat. Taurine (10 and 20 micrograms) injected unilaterally into the lateral ventricle of rats caused an increase in core temperature. Bilateral injection of taurine 2.5 and 5 micrograms into the preoptic region of the anterior hypothalamus induced a dose-related hyperthermia: higher doses (10 micrograms) caused hypothermia. Intrahypothalamically taurine-induced hyperthermia was blocked by prior injection of strychnine hydrochloride (5 and 15 micrograms); doses which alone had no effect on core temperature. Of the other inhibitory amino acids injected intrahypothalamically hypotaurine also induced a hyperthermia. GABA (10 micrograms) caused hypothermia; glycine (10 micrograms) had no effect. Potassium (50 mM) stimulated release of radioactivity from superfused slices of anterior hypothalamus prelabelled with [3H]taurine in a calcium-dependent manner. A high affinity uptake mechanism with a Km of 8.5 microM was demonstrated with [3H]taurine into slices of anterior hypothalamus. Taurine may have a neurotransmitter role in the anterior hypothalamus but whether the body temperature effects represent physiological or pharmacological events remains to be established.


Effects of external calcium concentration and pH on charge movement in frog skeletal muscle. 1. The effects of both external Ca2+ (1.8, 25, 50 and 100 mM) and external pH (pH 5.5, 7.15, and 9.0) on the voltage-dependence of charge movement in frog skeletal muscle were examined using the three intracellular micro-electrode voltage-clamp technique. 2. The two-state model of Schneider & Chandler (1973) was used to describe the voltage distribution of membrane charge. The parameters of this model are: Qmax, the maximum quantity of charge; V, the potential of equal distribution of charge; and k, a constant relating to the steepness of the charge vs. voltage relationship. 3. In 1.8 mM external Ca2+, alterations, in external pH shifted the transition potential, V, from a mean +/- S.E. of mean of -36.5 +/- 0.9 mV at pH 7.15 to -25.8 +/- 1.3 mV at pH 5.5 and to -42.5 +/- 1.8 mV at pH 9.0. These shifts are consistent with surface charge theory. No significant changes in Qmax or k were observed over the range of pH 5.5--9.0. 4. A reasonable fit of surface charge theory to the shifts in V over the range pH 5.5--9.0 could be obtained with surface charge densities and binding constants: sigma 1 = -1 e/165 A2, pK1 = 3.9 and sigma 2 = -1 e/400 A2, pK2 = 8. 5. However, at pH 7.15, both V and k changed with increasing external Ca2+ concentration. V shifted from -34.9 +/- 3.7 mV in 1.8 mM-Ca2+ to -13.8 +/- 5.1 mV, -19.3 +/- 3.6 mV and 3.3 +/- 9.3 mV in 25, 50 and 100 mM-Ca2+ respectively. k increased from 8.3 +/- 0.6 mV in 1.8 mM-Ca2+ to 15.3 +/- 1.4 mV, 14.6 +/- 1.6 mV and 20.0 +/- 2.9 mV in 25, 50 and 100 mM-Ca2+. Changes in k reflect decreases in the apparent charged particle valence from approximately 3 in 1.8 mM-Ca2+ to approximately 1.2 in 100 mM-Ca2+. As the external Ca2+ concentration was raised, Qmax was at least as large as that measured in 1.8 mM-Ca2+. The 43% decrease in the apparent valence of the charged groups cannot be explained by simple surface charge theory and may reflect a specific interaction between external Ca2+ and the charged groups. 6. Shifts in V with alterations in external pH and Ca2+ concentration are consistent with the effects of these agents on the contraction threshold of muscle fibres. This observation lends further support to the hypothesis that the charge movement is involved in gating muscle contraction and that the charged particles respond to changes in the electric field across the muscle cell membrane. 7. No difference was observed in the charge movement parameters of fibres from both room-temperature and cold-adapted frog tested at 2--5 degrees C in 1.8 mM-Ca2+ at pH 7.15.


Dependence of phrenic motoneurone output on the oscillatory component of arterial blood gas composition. 1. The hypothesis that respiratory oscillations of arterial blood gas composition influence ventilation has been examined. 2. Phrenic motoneurone output recorded in the C5 root of the left phrenic nerve and the respiratory oscillations of arterial pH in the right common carotid artery were measured in vagotomized anaesthetized dogs which had been paralysed and artificially ventilated. 3. The effect of a change in tidal volume for one or two breaths on phrenic motoneurone output was measured with the inspiratory pump set at a constant frequency similar to, and in phase with, the animal's own respiratory frequency. A reduction of tidal volume to zero or an increase by 30% led to a corresponding change of mean carotid artery pH level. The changes of carotid artery pH resulted in a change of phrenic motoneurone output, predominantly of expiratory time (Te) but to a lesser extent of inspiratory time (T1) and also peak amplitude of 'integrated' phrenic motoneurone output (Phr). Denervation of the carotid bifurcation blocked this response. 4. The onset of movement of the inspiratory pump was triggered by the onset of phrenic motoneurone output. When a time delay was interposed between them, the phase relationship between respiratory oscillations of arterial pH and phrenic motoneurone output altered. The dominant effect was to alter Te; smaller and less consistent changes of Phr and T1 were observed. 5. When the inspiratory pump was maintained at a constant frequency but independent of and slightly different from the animal's own respiratory frequency (as judged by phrenic motoneurone output), the phase relationship between phrenic motoneurone output and the respiratory oscillations of pH changed breath by breath over a sequence of 100-200 breaths, without change of the mean level of arterial blood gas composition. Te varied by up to 30% about its mean value depending on the phase relationship. Ti and Phr were also dependent on the phase relationship but varied to a lesser extent. The changes were comparable to the results obtained in paragraph 4. 6. It was concluded that phrenic motoneurone output is dependent in part on its relationship to the respiratory oscillations of arterial blood gas composition. 7. Information concerning a transient ventilatory disturbance is stored in the arterial blood in the form of an altered pattern of the respiratory oscillations of blood gas composition; this in turn can change breathing by an effect on the carotid bodies.


Hypothalamic receptors influencing the secretion of corticotrophin releasing hormone in the rat. 1. The production of corticotrophin releasing hormone (CRH) by the rat hypothalamus in vitro was studied in the presence and absence of various neurotransmitter substances and drugs which mimic or antagonize their actions.2. Acetylcholine, nicotine and bethanechol increased, in a dose-related manner, hypothalamic CRH release and content but the maximal responses to bethanechol or nicotine were less than those to acetylcholine.3. The actions of acetylcholine were antagonized by atropine, pempidine and hexamethonium but were completely inhibited only when atropine and pempidine were given together. The effects of nicotine were abolished by pempidine but not by atropine while those of bethanechol were abolished by atropine but not by pempidine.4. Acetylcholine-induced hypothalamic CRH activity was also antagonized by cyproheptadine but not by methysergide.5. 5-Hydroxytryptamine caused dose-related increases in hypothalamic CRH release and content. Its effects were antagonized by cyproheptadine and methysergide but not by atropine, pempidine or hexamethonium.6. Acetylcholine-induced increases in hypothalamic CRH production were reduced by GABA, noradrenaline, adrenaline, methoxamine and phenylephrine but not by isoprenaline. The actions of GABA were antagonized by bicuculline and those of noradrenaline by phentolamine but not by atenolol.7. The results suggest the presence of nicotinic and muscarinic cholinoceptors, 5-hydroxytryptamine receptors, alpha-adrenoceptors and GABA-receptors within the hypothalamus all of which may be important in the control of CRH secretion.


Correlations between variations of electrical field at the body surface and contractions of the stomach in guinea pig. 1. The slow potentiel changes of the base line of the electrocardiogram recorded by cutaneous electrodes, here called EGEG (electrogastroenterogram) have been recorded simultaneously with the electromyogram and pressure variations of the stomach antrum. 2. Periodic fluctuations of EGEG, 400 microV amplitude, were correlated with activities of the antrum EMG consisting of 3 to 6 mV spikes superimposed on slow wave of depolarization, and with gastric intraluminal pressure of 5 to 7 cm of water. 3. An anticholinergic drug abolished all those activities. A gastric contracture flattened the EGEG. 4. Rhythmic distensions of the antrum induced a synchronous modulation of EGEG, the magnitude of which was correlated with the amplitude of distension. These result suggest that the origin of EGEG is essentially the movements of stomach.


Fractionation and characterization of cystine aminopeptidase (oxytocinase) and arylamidase of the human placenta. Three activity peaks hydrolysing L-cystine-di-beta-naphthylamide (CysNA) and two activities hydrolysing L-leucine-beta-naphthylamide (LeuNA) were separated by gel filtration on Sepharose 6B from human placental tissue. The enzyme activities in the void volume and the solubilized enzyme activities with both substrates apparently are bound and free forms of the same enzymes (I) since detergent treatment caused a total disappearance of the activities in the void volume. The second distinct enzyme (II) was highly soluble and detected only with CysNA. The particle-bound enzyme(s) had a pH optimum at 6.5 with CysNA and at about 7.5 with LeuNA. They were highly sensitive to EDTA, could be reactivated by Co2+ and Zn2+ and were more sensitive to Ni2+ and L-methionine than the soluble enzyme II. The former enzyme(s) tolerated thermal treatment better than the soluble enzyme II. The solubilized free enzyme(s) I had a molecular weight of about 309,000. The soluble enzyme II was resistant to EDTA. Its optimum was at pH 6.0 and an estimate of 76,000 for the molecular weight was obtained.


In-vitro differentiation of type A spermatogonia in mouse cryptorchid testis. Cryptorchid testes from adult mice were incubated in calf serum-supplemented medium. There was an effective differentiation of adult type A spermatogonia up to the pachytene stage of meiotid division whcih resembled the process of spermatogenesis in vivo. In the absence of calf serum, type A spermatogonia did not differentiate at all. They differentiated when the serum was present for the first day, but was absent for the rest of cultivation. These results indicate that serum is necessary for only the early process of spermatogenesis from type A spermatogonia in vitro and not for the further processes of germ cell differentiation. Type A spermatogonia cultured in serum-free medium retained the ability to differentiate for at least 3 days.


Familial polyposis coli: heterogeneous polyp expression in 2 kindreds. We describe 2 extended kindreds supposedly manifesting familial multiple adenomatous polyposis coli (FPC), but which show marked heterogeneity in the phenotypic expression of colorectal adenomatous polyps. In one family, 2 individuals had diffuse polyposis at very early ages (7 and 10 years), while 6 others (aged 23 to 72 years) had solitary polyps only. Of the patients with solitary polyps, 2 had associated colonic malignancies (ages 26 and 35), while another had a prophylactic colectomy performed at age 46. In the second family, 5 of the 11 patients with evidence of polyps showed the classical presentation of FPC, while the remainder showed marked phenotypic variation. The marked variability in frequency and location of colon polyps points to the need to reassess our traditional criteria for diagnosis of FPC. The high risk of early onset colon cancer in patients from these families who have the most minimal manifestation, namely isolated polyps, recommends more careful scrutiny of supposedly unaffected members of all FPC kindreds.


Characterisation and neutralisation of Aeromonas hydrophila enterotoxin in the rabbit ileal-loop model. Cell-free culture filtrates and crude enterotoxin preparations from six strains of Aeromonas hydrophila caused the accumulation of fluid in rabbit ileal loops. This activity was due to a non-dialysable, heat and acid-labile antigenic protein and was lost when culture filtrates and crude enterotoxin preparations were heated at 60 degrees C for 20 min. or 56 degrees C for 30 min. respectively. Maximum activity was observed at pH 8.0-10.0; there was a gradual loss at lower pH and activity was abolished in culture filtrates held at pH 3.0 and crude enterotoxin preparations held at pH 4.0. Titration of the crude enterotoxin preparations in rabbit ileal loops showed that the ED50 (equivalent to 1 unit of toxin) was contained in 25 microgram of protein; a logarithmic plot of the neutralisation coefficients against antiserum concentrations showed that one unit of antitoxin was contained in 42 x 10(-4) ml of the antiserum.


Effects of excitatory and inhibitory amino acids on phasic respiratory neurons. The responsiveness of phasically active brainstem respiratory neurons to several amino acids was investigated in cats under Dial anesthesia. Four-barreled microelectrodes were used to extrude iontophoretically the putative neurotransmitters L-glutamate, L-asparatate, glycine, and gamma-aminobutyric acid (GABA), L-glutamate and L-aspartate caused increased activity when applied to either inspiratory or expiratory neurons and appeared to be equal in efficacy. Likewise, GABA and glycine depressed ongoing phasic neural activity of both inspiratory and expiratory units. In this case, however, the dosage of GABA required to produce a given depression was significantly less than the required dosage of glycine. These findings support the hypothesis that L-glutamate and/or L-aspartate may act as excitatory neurotransmitter agents at the synapses of brainstem respiratory neurons and conversely, GABA may act as the natural inhibitory neurotransmitter.


Further observation on the denervation supersensitivity of the urethra in patients with chronic neurogenic bladders. The response of the urethra in patients with chronic neurogenic bladders to autonomic stimulation was investigated by urethral pressure profile. A consistent supersensitivity to alpha-adrenergic stimulation was documented. Experiments with various autonomic blocking drugs confirmed that this response is alpha-adrenergically mediated via the short neuron system. The results appear to offer pharmacological evidence for the recently evolving intricate innervation pattern of the urethra including its distal portion, where the alpha-adrenergic system is believed to be important.


Influence of immune status on virus-derived transplantable hepatoma in chickens. The transplantable MC-29 virus-derived hepatoma is a suitable model for studying the influence of immune status on virus-derived hepatomas in chickens. It was found that both humoral and cellular immunologic reactions have a role in the pathogenesis of virus-derived hepatomas and that virus-derived hepatomas can be influenced by nonspecific immunostimulation. The lymphoid system was profoundly altered in hepatoma-bearing chickens; this cannot be neglected when studying correlations between immune reactions and carcinogenesis. Profound changes were also observed in protein synthesis and the steroid receptor system of hepatoma-bearing chickens compared to healthy birds; this also complicates the understanding of the role of immune mechanisms in carcinogenesis.


Perfusion techniques of the canine pancreas for physiological and secretin response studies. In vivo and in situ perfusion techniques of the canine pancreas for physiologic and secretin response to studies are described. We developed these modified techniques to clarify the mechanism of the pancreatic exocrine secretion. An analysis was made of some physiological parameters of the pancreas and our findings were compared with those obtained in secretin stimulation of the pancreas. The composition of secretin induced venous effluent and pancreatic juice was investigated. A decrease of pH, pO2 and (HCO-3) in the venous blood and a temporary efflux of K+ from the cell to the perfusate were observed after secretin stimulation. A temporary decrease of perfusion pressure was observed after secretin stimulation and the change is thought to be due to vascular dilatation. Ultrastructural findings from the pancreas perfused for about 1 hour showed no prominent changes.


[The sympathetic neuron: regulation mechanisms for transmitter synthesis, transmitter release, and stimulus response (author's transl)]. A great multitude of factors acting at different sites of the afferent sympathetic nerve are capable to modify the magnitude of its stimulus-induced effects. 1) Specific receptors, located at the ganglionic synapse display inhibitory of facilitatory effects on the ganglionic transmission of the nerve impulse. 2) The rate of synthesis of the neurotransmitter noradrenalin is regulated at the level of the tyrosine hydroxylase. Transsynaptic mechanisms adapt the rate of synthesis of noradrenalin to nerve activity and transmitter release. 3) The amount of transmitter released per nerve impulse is controlled by a variety of receptors located presumably presynaptically at neuronal sites. Inhibitory and facilitatory "auto"-receptors stimulated by the released transmitter itself represent a local feed-back control. Similarly receptors for transmitters of cholinergic or serotoninergic neurons as well as autacoid hormones are involved in the local control of noradrenalin release. In addition, kinines, prostaglandins, or compounds like adenosine, some of them released from the target cells by the sympathetic stimuli or delivered by the blood stream are involved in the modulation of stimulus-evoked noradrenalin release. 4) Stimulus responses of the target cells can be modulated by similar mechanisms.


[Biochemical effects of psychotropic drugs in central nervous system (author's transl)]. Studies on the biochemical effects of clinically used psychotropic drugs in brain have shown that they all exert their action by a direct or indirect interference with synaptic transmission. Thus, animal studies in vivo and in vitro have shown that the clinical efficacy of antipsychotic drugs correlates with their inhibitory action on dopamine receptors. In vivo these compounds enhance dopamine turnover in the brain and in vitro they inhibit the dopamine sensitive adenylate cyclase and the binding of dopamine to its receptor at neuronal membranes. Tricyclic antidepressants are drugs which have effects on many transmitter systems. No specific biochemical action has been found which is closely correlated with their clinical potency. However, it appears that a stimulation of the function of the noradrenergic system might have some clinical relevance. Benzodiazepines exert their pharmacological activity in the CNS by interacting with a brain specific receptor. This receptor appears to be part of a larger complex including a GABA receptor and the chloride conductance mechanism associated with the GABA receptor. By binding to their receptor, benzodiazepines appear to enhance the sensitivity of the GABA receptor, thus indirectly potentiating GABA-ergic neurotransmission in the brain.


Intramyocardial pH as an index of myocardial metabolism during cardiac surgery. At present, a practical method for continuous monitoring of the state of tissue metabolism in the individual patient's heart during cardiac operations is not available. We have explored the use of miniature electrode measurements of myocardial interstitial pH to provide this monitoring capability, making comparisons with intracellular pH in left ventricular biopsy specimens and with tissue PCO2 measured by mass spectrometry. The electrode system consisted of a hydrogen ion-sensitive glass miniature electrode, housed in the beveled end of a 21 gauge (0.8 mm diameter) hypodermic needle, and a 2 mm diameter reference electrode, with an internal silver-silver chloride electrode coupled to tissue through a saline bridge (150 mM/L sodium chloride) saturated with silver chloride. Accuracy in blood at 37 degrees C was compared with conventional instrumentation (Radiometer BMS-3 MK-2 Blood Micro System) over a pH range of 7.4 to 6.4 with linear regression analysis (n = 26) revealing a high correlation (r = 0.997) and a mean difference in paired observations of only 0.01 +/- 0.004 (mean +/- SEM) pH units. In two groups of dogs on cardiopulmonary bypass, the pH needle and reference electrodes were inserted into the anterior wall of the left ventricle. Ischemic arrest of the heart at 37 degrees C was used to vary myocardial pH. In Group 1 (n = 8), intracellular pH was estimated from left ventricular biopsy specimens (400 mg each) taken over a microelectrode pH range of 7.37 to 6.37, snap frozen, and homogenized. In Group II (n = 6), tissue PCO2 in the anterior wall of the left ventricle was determined by mass spectrometry (sampling catheter 1.3 mm diameter). Miniaturized electrode (interstitial) pH exceeded biopsy (intracellular) pH under control conditions by 0.28 +/- 0.025 pH units (p less than 0.001), but below an electrode pH of 6.8 the results of the two techniques did not differ significantly. The tissue PCO2 rose from 69 +/- 2 mm Hg to a final plateau of 419 +/- 25 mm Hg, which was similar to the predicted value of 427 +/- 28 mm Hg calculated from the pH change (7.37 +/- 0.01 to 6.01 +/- 0.07), providing a further independent check on the pH electrode technique. These data indicate that our intramyocardial pH measurements do reflect intracellular metabolism during elective arrest of the heart and may have potential for clinical use.


The physician assistant in rural primary care practices: physician assistant activities and physician supervision at satellite and non-satellite practice sites. Nineteen practice sites in Iowa were studied to determine the differences in the types of physician (MD) supervision the physician assistant (PA) received at work at satellite (separate from the major practice site of the supervising MD) and non-satellite practice sites. The MDs supervised PA functions in 12.9 per cent of the patients seen by the PAs at non-satellite and 15.9 per cent of patients they saw at satellite practice sites. All patients with presenting manifestations that suggested life-threatening conditions were seen by MDs at satellite and non-satellite sites. The MD spent 9.2 minutes per patient at satellite clinics, compared to 4.4 minutes per patient at non-satellite clinics. PAs working at satellite sites appeared to receive as much supervision as PAs working at non-satellite clinics.


Public attitudes toward some changes in the division of labor in medicine. This study examined public attitudes toward the delegation of medical tasks to nonphysician health workers. Data were obtained in household interviews of a probability sample of the adult residents of Cuyahoga County, Ohio (N = 808). The proportions of the sample giving approval to care from nonphysicians varied widely among the 18 tasks on which opinions were elicited. The results of the public survey were compared to those from an earlier national survey of physicians. Physicians' responses paralleled the responses of the lay public regarding most tasks. However, with respect to regular checkups on babies and prenatal checkups, markedly higher proportions of the physicians than the public were willing to delegate to nonphysicians. The analysis indicated that public attitudes toward task delegation in medical practice do not bear strong relationships to social status indicators, political self-designations, or preceived health status.


Physiological studies on Phymatotrichum omnivorum. IX. Synthesis of indole acetic acid in vitro. The cotton root rot fungus, Phymatotrichum omnivorum, synthesized indole acetic acid (IAA) in culture medium containing tryptophan as the only source of nitrogen. Synthesis of IAA was not affected by illumination, and maximum amounts of the auxin were produced at 30 days. The optimum hydrogen ion concentration and temperature for IAA production were 6.5 and 28 degrees C, respectively. Indole ethanol (IEA) was also detected in tryptophan media, primarily during the active growth of the organism.


[Balanced and unbalanced growth of periodic and continuous cultures of Candida utilis]. The paper presents mathematically treated data published in literature about the specific growth rate mu and the economic coefficient Y in Candida utilis at the exponential growth phase, at the transient state in chemical from the limitation of growth with a source of carbon and energy to the inhibition with low pH values, and at the stationary state in chemostat. Both parameters show attenuated oscillations in the first two cases, but are constant in the third case. The oscillations of mu and Y are synchronous and their interrelationship is directly proportional. The values of Y may be negative since the cell weight can decrease though the cell still assimilates the substrate. The specific rate of substrate assimilation in oscillations remains constant. Proteins can by synthesized at two different rates while the growth rate is one and the same.


Pharmacokinetics and tolerability of a single oral 600-mg dose of doxycycline. The pharmacokinetics of a single orally administered 600-mg dose of doxycycline (six 100-mg film-coated tablets) was studied in 18 healthy subjects. Plasma doxycycline levels remained above 1.35 mumol/L for 48 hours and compared favourably with the mean inhibitory concentrations of doxycycline against the common infecting organisms in chronic bronchitis. In a separate tolerability study in 37 healthy subjects, there was no significant difference between doxycycline and placebo in the incidence of adverse effects.


[Determination of the optimal growth conditions for microorganisms by using l4C-bicarbonate]. A technique of short-term experiments using 14C-bicarbonate has been proposed for rapid determination of the optimal conditions of growth of autotrophic and heterotrophic microorganisms. The technique is described and its advantages and limitations are discussed.


[Effect of KH2PO4 on Streptococcus lactis growth and nisin synthesis when the medium is kept at a constant pH]. When the pH of the medium was maintained at the level of 6.6--6.8 and the content of KH2PO4 in it was decreased, the biosynthetic activity of Streptococcus lactis, strain MGU, became lower. The culture assimilated low quantities of phosphorus from KH2PO4 at a high concentration of this salt in the medium; presumably, the culture required large quantities of potassium ions. If the pH of the medium is maintained at a constant value, the fermentation can be stopped 21 hr after the beginning of cultivation of Str. lactis, strain MGU.


Ventricular tachycardia in a patient on dehydroemetine and chloroquine for amoebic liver abscess. A case of ventricular tachycardia in patient who was being treated with dehydroemetine and chloroquine for amoebic liver abscess is reported. The patient had 15 episodes of this arrhythmia. The hazard of using dehydroemetine and chloroquine in conventional doses, even sequentially, is emphasized.


[Principle growth indices of a chemostat Candida utilis culture resistant to acid pH values]. The kinetics of growth of the Candida utilis chemostat culture 1668-3-37 was studied in a synthetic medium with ethanol at different values of pH and temperature. Chemostat curves were obtained for the pH of the medium of 4.5 and 3.0 and the temperature of 32 degrees C. The following growth characteristics were determined: the maximal growth rate (mumax), the economical coefficient (Y), the substrate (saturation) constant (Ks), the rate of ethanol uptake (q), maintenance energy (m). The minimal amount of ethanol inhibiting the yeast growth was assayed in short-term experiments under periodic conditions with shaking. The value of mumax was 0.35 hr-1 when the yeast was cultivated at 32 degrees C and the pH 4.5, and 0.32 hr-1 at the pH 3.0. The value of Ks varied by an order of magnitude at different pH values when the chemostat culture was grown at D=0.2 hr-1: 36.0 mg/litre at the pH of 3.0 and 3.75 mg/litre at the pH of 4.5. The value of m was close to 0 at the pH of 4.5 and equaled 5--7 mg of ethanol per gram of dry biomass per hour at the pH of 3.0; it was still higher when the temperature of cultivation was increased to 38 degrees C. The minimal substrate (ethanol) concentration inhibiting the yeast growth was constant at different cultivation conditions (pH 3.0 or 4.5 and temperature 32 or 38 degrees C), being equal to 0.45% (v/v) of ethanol.


Biological autoxidation. I. Decontrolled iron: an ultimate carcinogen and toxicant: an hypothesis. Ionic iron at physiological pH hydrolyzes into insoluble aggregates, which disperse on slight acidification. Uncontrolled ionic iron promotes autoxidation, which crosslinks biomolecules and produces destructive activated oxygen. Defenses against autoxidative crosslinking include: 1. ferritin, the macromolecular scavenger of iron; 2. metabolic turnover, which prevents irreversible crosslinking through early catabolic degradation and replacement; and 3. enzymatic deactivation of oxygen. I am proposing that the anticrosslinking defenses are defeated by transient actions of metabolic perturbations, toxicants, oxidants and "foreign bodies", which cause oxidative crosslinking of proteins and lipids into irreversible tissue imprint: indigestible bodies containing porous limited-access spaces (LASs). The pores exclude the macromolecular ferritin and the digestive and antiautoxidation enzymes but admit ionic iron which, sheltered from ferritin, accumulates into decontrolled-iron pathogen (DIP). DIP utilizes the energy of ambient pH fluctuations to erupt from the LAS, swamp the available ferritin, poison the surroundings, catalyze autoxidation and crosslink cell components into additional LAS carriers. With time and sufficient promotion by pH fluctuations or metal-complexing agents, DIP and LAS expand. DIP injures through heavy-metal inhibition of life processes and catalysis of autoxidation. Typically, carcinogenic initiators are protein denaturants, cell poisons, "foreign bodies" and autoxidation catalysts. These are DIP-initiating properties, and DIP may be a preneoplastic stage of carcinogenesis. A DIP-model interpretation is given for the growth of asbestos bodies. DIP is an inorganic parasite. It may envelope and attack phagocytized particles.


Myo-inositol-1-phosphate synthase from streptomyces griseus (studies on the biosynthesis of cyclitols, XXXVIII). It could be shown that Streptomyces griseus, the microorganism producing the antibiotic streptomycin and also mutant strains of this species that cannot synthesize streptomycin, possess myo-inositol-1-phosphate synthase (EC 5.5.1.4), the enzyme cyclizing D-glucose 6-phosphate. The enzyme isolated from that organism is extremely instable, its molecular weight is approximately 260,000, and it requires a divalent metal ion for its activity. This is the first instance that an enzyme of this specificity has been found in a prokaryotic organism.


Description and application of a personal ultraviolet dosimeter: a review of preliminary studies. Preliminary work on a dosimeter suitable for measuring UVR exposure on individual persons is described. It is based on the use of polysulfone film which, on exposure, shows a change in absorbance that is determined spectrophotometrically. The results of studies of groups of persons with vastly different degrees of solar exposure, e.g., outdoor and indoor workers and geriatric patients, and psychiatric patients with photosensitivity from phenothiazine drugs are presented. We consider the dosimeter may also be suitable for epidemiologic studies in sunlight-induced skin cancer.


Fundamental difference between the molecular interactions of agonists and antagonists with the beta-adrenergic receptor. Antagonist binding to the beta-adrenergic receptor is largely entropy driven, with only a small enthalpy component. The binding of agonists, on the other hand, is associated with a large decrease in enthalpy which permits a highly unfavourable decrease in entropy. The thermodynamic differences between the binding of agonists and antagonists may provide new insights into the molecular basis for hormone stimulation of adenylate cyclase activity.


Substance P: model studies of its binding to phospholipids. 1. The partition of substance P (SP) between buffer solutions (pH 1.6--7.8) and an organic, phospholipid (phosphatidyl serine, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidyl choline) containing phase (chloroform:methanol 2:1) was studied. 2. The binding of SP to phosphatidyl serine, phosphatidyl ethanolamine and phosphatidyl inositol was lowest at pH 2 and increased with pH. The binding to phosphatidyl choline was much smaller and less dependent on pH. 3. In contrast to the basic peptide SP (pI 10.5), physalaemin (pI 7.0) did not show any binding to phospholipids at any investigated pH value which underlines the importance of a basic group in the peptide for its binding. 4. The high affinity (KD = 0.1 microM) and capacity of 44 pmol SP/microgram phosphatidyl serine and 48 pmol SP/microgram phosphatidyl ethanolamine at pH 7.2 under conditions of saturation contrasted with the very low binding of SP to phosphatidyl inositol or phosphatidyl choline. Ionic bindings between the basic peptide and phosphatidyl serine or phosphatidyl ethanolamine are regarded to be predominant, although other binding forces cannot be excluded. 5. There was a concentration-dependent reduction in the binding of SP to phosphatidyl serine or phosphatidyl ethanolamine by Na+ and Ca2+, whereas K+ showed hardly any effect at physiological concentrations. 6. The model studies served to consider the possibilities of the binding of a basic peptide to lipid storage or receptor sites.


Selective stimulation of central alpha-autoreceptors following treatment with alpha-methyldopa and FLA 136. 1. The accumulation of normetanephrine in the rat brain induced by the monoamine oxidase inhibitor nialamide was inhibited following alpha-methyldopa and 4-amino-3-(2,6-dichlorobenzylidenehydrazino)-1,2,4-triazole (FLA 136). It was not changed following alpha-methylmetatyrosine despite a greater disappearance of noradrenaline than after alpha-methyldopa. The alpha-adrenoreceptor blocking agent yohimbine increased the nialamide-induced accumulation of normetanephrine and completely antagonized the actions of alpha-methyldopa and FLA 136, indicating that the effects of the two drugs are due to stimulation of alpha-adrenoreceptors. 2. The flexor reflex activity of spinalized rats was not influenced by alpha-methyldopa and alpha-methylmetatyrosine at the doses used in the biochemical experiments, as previously found for FLA 136, indicating no stimulation of classical, postsynaptic, central alpha-adrenoreceptors. 3. The biochemical effects of alpha-methyldopa and FLA 136 might be caused by stimulation of alpha-autoreceptors on the cell bodies and the nerve terminals of noradrenaline neurons. A similar mechanism might be involved in the hypotension reported by other investigators following these drugs.


Effect of kainic acid injections and other brain lesions on vasoactive intestinal peptide (VIP)-stimulated formation of cAMP in rat brain. In rat striatal slices, both intrastriatal kainic acid injection, which destroys striatal neurones, and intranigral injection of 6-hydroxydopamine (6-OHDA), which leads to a degeneration of dopamine nerve terminals in the striatum, reduced vasoactive intestinal peptide (VIP)-induced cAMP accumulation by approximately 60%. Cortical ablation, which leads to degeneration of cortico-striatal fibres, had no effect on striatal VIP-induced cAMP formation. Knife cut lesions transecting the stria terminalis, which destroy afferent fibres to the amygdala, decreased the VIP-induced increase in cAMP in amygdala slices by 40%, while kainic acid injection into the amygdala had no effect. Kainic acid injection into several other brain regions, including hippocampus, cortex and hypothalamus also failed to affect the VIP-elicited increase in cAMP in slices, despite reductions in choline acetyl-transferase, glutamate decarboxylase, cyclic nucleotide phosphodiesterase and basal levels of cAMP. The results of a study of the effects of various VIP fragments on cAMP stimulation in striatal and cortical slices suggests that the entire sequence of VIP is necessary for full activity. The results suggest that VIP may be involved in neuromodulation or neurotransmission in the striatum and/or nigrostriatal pathway and also in the stria terminalis from the bed nucleus to the amygdala.


Changes in protein-bound calcium during haemodialysis in relation to bone disease. 29 patients receiving haemodialysis treatment for chronic renal failure were divided into two groups on the basis of the presence or absence of bone disease as defined by radiology and bone alkaline phosphatase. The group of patient with bone disease showed a significantly greater increase in protein-bound calcium during dialysis compared with the control group. There were no significant differences in the changes in total calcium, albumin or hydrogen ion concentration during dialysis between each group. The data suggest that there is a relationship between the increase in protein-bound calcium during dialysis and the incidence of bone disease.


Inhibition of nitroso chemical carcinogen activation of rat hepatic guanylate cyclase by anticancer agents. Recent studies have demonstrated that nitroso chemical carcinogens activate guanylate cyclase (EC 4.6.1.2) which catalyzes the production of guanosine 3',5'-monophosphate. This nucleotide is thought to be involved in normal and abnormal cell growth. We examined the effect of 3 major classes of anticancer chemotherapeutic agents, the antimetabolites (methotrexate and 6-mercaptopurine), antitumor antibiotics (adriamycin and actinomycin D), and alkylating agents (cytoxan, uracil mustard, isophosphamide, chlornaphazine, and 1-propranol-3,3'-iminodimethane sulfonate) on the activation of guanylate cyclase by nitroso chemical carcinogens. The anticancer chemotherapeutic agents noncompetitively blocked the activation of rat hepatic guanylate cyclase by N'-nitro-N-nitroso-N-propylguanidine (NNPG) and hydrazine. Adriamycin, methotrexate, and uracil mustard were the most effective inhibitors completely abolishing the effect of 1 mM NNPG on guanylate cyclase activity. The remainder of the anticancer chemotherapeutic agents abolished the NNPG activation of guanylate cyclase 40--70%. Since a previously described guanylate cyclase inhibitor has been shown to terminate the growth of an undifferentiated prostatic cancer in tissue culture the present data may indicate that one of the mechanisms by which anticancer chemotherapeutic agents exert their effects is by inhibition of tumor guanylate cyclase activity.


The mechanisms of lectin-mediated cell agglutination. The interaction between lectins and cells is a well established phenomenon. However, the way by which this interaction occurs is still unclear and published observations are sometimes contradictory. This article attempts to reconciliate the available information concerning this problem in order to find support for a new model of lectin-mediated agglutination of cells. The traditional idea favours the carbohydrate-directed interaction as the main reason of binding of lectins to the cell surface. Nevertheless, lectins molecules are so diversified in physical chemical and biological properties, as well as in structure, that such generalization cannot be stated without risk. Furtheremore, the agglutination mechanism itself is too complex to assume that lectins are only functional "bridges" that hold two cells together. The effect noticed when agglutination is studied with different cells and different lectins at various conditions, suggest that other factors are to be taken into account.


Effect of lead exposure on the activity of some hepatic enzymes in the rat. Seven-day-old rats were fed 1% lead acetate tetrahydrate solution for 2, 4, or 7 days. Adult rats were fed the same lead solution for 6--8 wk. In the newborn rats, hepatic UDP-bilirubin glucuronyl transferase (GT) and gamma glutamyl transpeptidase (GGTP) activities were markedly increased. GT activity was increased after 4 days as compared to the controls (6.3 +/- 0.3 vs. 4.3 +/- 0.3, P less than 0.001), and was maximal after 7 days of treatment (7.5 +/- 0.4 vs. 4.6 +/- 0.4, P less than 0.001). GGTP activity was already maximally increased after 2 days of lead treatment (1.4 +/- 0.2 vs. 0.4 +/- 0.1, P less than 0.001). Hepatic GT and GGTP activities were similarly increased in adult rats (7.9 +/- 0.3 vs. 5.1 +/- 0.1, P less than 0.001, and 0.7 +/- 0.1 vs. 0.4 +/- 0.1, P less than 0.005, respectively). In vitro studies adding lead citrate to liver homogenates did not produce any direct effect on GT and GGTP activities.


Increased work of breathing associated with nasal prongs. To see if continuous distending pressure (CPD) given by nasal prongs increases work of breathing, we measured the mechanics of breathing, minute ventilation, and blood gases in nine infants with both nasal prong and face mask CDP. Minute ventilation was 16% larger (P less than .02), work of breathing was 94% higher (P less than .01), and the mean PaO2 was 8 mm Hg lower (P less than .03) with the nasal prongs. There was no difference in pH or PaCO2. We speculate that CDP given by nasal prongs may increase the risk of respiratory failure in the premature infant already compromised with hyaline membrane disease.


[Hypertension due to unilateral parenchymatous nephropathy (author's transl)]. One hundred and eight patients suffering from hypertension due to a unilateral parenchymatous neophropathy were studied over a period of one to eight years after treatment was starded. The aetiologies were diverse: harmonious hypoplasia, segmental hypoplasia, pyelonephritis, reflux nephropathy, hydronephrosis and tuberculosis. Thirty nine patients were treated surgically, with 50% good results. In 82 cases medical treatment was continued for at least a year with a 52% success rate. Such success was recorded in 94% of cases in which beta-blockers were used (38 cases). Surgical success was not dependent upon the period for which hypertension had been present. The best results were seen in cases of hydronephrosis and pyelonephritis and the worst in tuberculosis. Thirteen patients underwent surgery event though there was no unilateral increase in plasma renin levels. Seven were improved or cured. Ten patients underwent surgery with a renin activity 50% greater than on the healthy side, 9 being improved or cured. Treatment with beta-blockers, alone or in association with diuretics, controlled blood pressure in 90% of cases, regardless of the renin activity. Plasma renin activity in the renal veins is of good prognostic value in terms of the effectiveness of nephrectomy against hypertension. In Call cases, beta-blockers were more effective than surgery.


Complexing of reduced technetium and tin(II) by chelating phosphate compounds. II. In vitro stability of pyrophosphate and ethane-1, hydroxy-1, diphosphonate (EHDP) complexes. The in vitro stability of 99mTc- and 113Sn-pyrophosphate and ethane-1, hydroxy-1, diphosphonate (EHDP) complexes was studied by varying the mode of preparation. The 1-hr distribution in the rat was used as an indicator for complex formation or destruction. A maximum of bone uptake and urinary excretion and a minimum of soft tissue concentration was obtained if there was an excess of phosphate in relation to tin(II) in the equilibrium. Formation of tin(II) colloid was favoured in the presence of an excess of tin(II) in the equilibrium, 99mTc colloid occurred with some delay. After dilution in neutral normal saline the chelates were more or less destroyed, as shown by a 113Sn(II) colloid formation whereas the 99mTc-phosphate complexes were transformed into a 99mTc kidney agent. At pH 11 the 113Sn(II)-phosphate complexes proved to be stable, the 99mTc-phosphate complexes were also transformed into the 99mTc kidney agent. Oxidation of all tin(II) in the equilibrium by hydrogen peroxide did not change the distribution patterns of 113Sn, 99mTc was oxidized to pertechnetate. In general complexes between tin(II) and chelating phosphate compounds proved to be more stable than those with reduced technetium. EHDP was found to form stronger complexes with tin(II) and reduced technetium than pyrophosphate.


Complexing of reduced technetium and tin (II) by chelating phosphate compounds. I. Chemical state of technetium. Complexing of reduced 99mTc, 99Tc and of 113Sn(II) by pyrophosphate was studied, using the in vivo distribution in the rat as an indicator for complex formation. 99mTc-pyrophosphate was only formed at very low technetium concentrations, otherwise colloid formation occurred. Reduced 99mTc in trace amounts and 113Sn(II) complexed equimolarly with pyrophosphate were concentrated in bone and excreted in urine in comparable amounts. The in vivo distribution of 32P-orthophosphate and -pyrophosphate was characterized by a considerable uptake in the liver and a poor urinary excretion. The distribution patterns of 32P-pyrophosphate, complexed equimolarly with tin(II), remained unchanged. Despite these findings it is concluded that real chelates are formed, since non-complexed reduced 99mTc was not concentrated in bone. Two variants of reduced technetium could be discerned: a 99mTc-kidney agent and a 99mTc protein-bound agent. Some evidence was found that reduced technetium may change its oxidation state, but it seems much more likely that both agents are technetium(IV) compounds. It is suggested that the kidney agent is hydrated technetium dioxide whereas the protein-bound agent is a charged technetium(IV) compound. Only hydrated technetium dioxide is obviously complexed by chelating phosphate compounds.


Effect of cranberry juice on urinary pH. Twenty-one female and 19 male subjects who had normal physical and laboratory examinations were randomly assigned into four groups of 10 subjects each. Each group was then randomly assigned a number (150, 180, 210, 240) which determined the amount of cranberry juice, in milliliters, members of that group would ingest with each meal during the experimental phase of the study. The study took place over a 12-day period. A one-group before-and-after design was used, with each subject serving as his or her own control. Diet was controlled; menus on days 1 through 6 were repeated on days 7 through 12 with the addition of cranberry juice at each meal. Subjects used nitrazine pH tape to measure the pH of midstream urine at each voiding. There were significant (.01 level) differences in mean urinary pH between each control group and its corresponding experimental group. Anticipated problems with increased number of bowel movements, weight gain, increased voiding frequency, and subject pH measurement inaccuracy did not occur.


Compatibility of high doses of both oral domperidone and neuroleptics in chronic psychotics. Twenty chronic schizophrenic inpatients who were being treated with high doses of neuroleptics and of whom seven had extra-pyramidal symptoms in spite of anti-Parkinsonian therapy, were given oral domperidone (50 mg t.d.s. for 2 weeks) for the relief of chronic dyspepsia. The dyspepsia symptoms were markedly improved, no side effects were seen and, even at high doses, domperidone did not intensify the existing extra-pyramidal side effects of the neuroleptics or produce new ones.


Effect of pH on eggshell penetration by Salmonellae. Experiments were conducted to study effects of pH on penetration of eggs by three species of Salmonella. Eggs having an average specific gravity of 1.078 were subjected to challenge by either S. typhimurium, S. st. paul, or S. derby. Challenge solutions ranged from pH 5.0 to 9.5 in .5 pH increments and contained an average of 7.5 x 10(3) Salmonella/ml. Egg temperature was 22 C and solution temperature 4.4 C when challenged. Tartaric acid (10%) or 1 N. NaOH were used to adjust solution prior to adding challenge organisms. Eggs were challenged for 3 min then allowed to dry and held at 22 C for 24 hr, after which they were opened aseptically. Salmonella penetration was determined by swabbing the inner shell membrane and incubating in selenite cystine and tetrathionate enrichment broths for 24 hr followed by plating on MacConkey and SS agars. Penetration rates for all three organisms were significantly less at pH 5.0 than at any higher pH tested. There was an increase in penetration from pH 5.5 to 7.0 for all species. Maximum penetration rates were 42% of eggs challenged at pH 7.5, 22% at pH 8.5, and 34% at pH 7.0 for S. typhimurium, S. derby, and S. st. paul, respectively. In no case was penetration of eggs at pH 9.0 significantly different from pH at maximum penetration of challenge eggs. Penetration by S. st paul, at pH 9.5 was significantly less (P less than .05) than at pH 7.0. Decalcification of the eggshell was less than .01%/min at pH 4.0. Shell losses at pH 3.5 and 3.0 were .03% and .33%/min, respectively.


Evaluation of organic acids and other compounds as Salmonella antagonists in meat and bone meal. Twelve compounds were evaluated as salmonella antagonists in commercial meat and bone meal. The test organism was a nalidixic acid-resistant strain of Salmonella infantis. Adequate moisture to support salmonella growth was assured by the addition of 40% water to each 50 g test sample. Compounds were tested at levels permitted for food additives except formalin which has not been approved. Salmonella counts were determined every few days by spread plates and the pH was recorded from the initial 1:10 dilution. Although the salmonella population initially declined in the presence of several additives, none of the compounds were effective in preventing salmonella multiplication in the MBM except formalin at levels greater than .1%.


Fucntional specialization and binocular interaction in the visual areas of rhesus monkey prestriate cortex. If is is believed that neural mechanisms mediating stereoscopic vision may be localized in specific areas of the visual cortex, then it becomes necessary to be able to define these areas adequately. This is no easy matter in the rhesus monkey, an animal close to man, where the cytoarchitecturally uniform prestriate cortex is folded into deep sulci with secondary gyri. One way around this awkward problem is to use the callosal connections of the prestriate cortex as the anatomical landmarks. Callosal connections are restricted to regions at which the vertical meridian is represented. Since the visual fields, including the vertical meridian, are separately represented in each area, each has its own callosal connections. These are of great help in defining some of the boundaries of these areas, since the boundaries often coincide with the representation of the vertical meridian. With the visual areas thus defined anatomically, it becomes relatively easy to assign recordings to particular areas. Studies of binocular interactions in these areas reveal that most cells in all prestriate areas are binocularly driven. Hence, theoretically, all of the prestriate areas are candidates for stereoscopic mechanisms. The degree of binocular interaction varies from cell to cell. At the two extremes are cells which either respond to monocular stimulation only and are inhibited by binocular stimulation or ones which respond to binocular stimulation only. Changing, as opposed to fixed, disparity is signalled by two types of cells. In one category are cells activated in opposite directions for the two eyes. Such cells are always binocularly driven. In the other category are cells, some of which are monocularly activated, that are capable of responding to changing image size. In the monkey, both these categories of cells have so far been found in the motion area of the superior temporal sulcus only.


Brain damage and global stereopsis.

Brain damage and global stereopsis. When a single object lies in front of or beyond the plane of fixation its retinal image lies on disparate positions in the two eyes. This 'local' retinal disparity is an excellent cue to depth, and retinal disparties of a few seconds of arc are detectable by people and monkeys. However, most visual scenes produce a complex array of contours in each eye and we can detect the disparity in the arrays despite the ambiguous nature of the disparities, i.e. each contour in one eye could be related to any of several similar contours in the other eye. This ability, known as 'global' stereopsis, may be selectively impaired following brain damage in man. Global stereopsis was measured in rhesus monkeys before and after removing a different cortical visual area in different groups of animals. Only removal of the inferotemporal cortex impaired global stereopsis. The result is related to the findings with human patients and to receptive field properties of neurons in the inferotemporal cortex of monkeys.


Depth sensitivity of binocular cortical neurons of behaving monkeys. Activity of neurons if foveal striate and prestriate cortex of trained rhesus monkeys was recorded with metal microelectrodes. While animals fixated a small spot at a given fixation distance (38 or 57 cm), bright or dark bars moving across a frontoparallel plane were presented at different depths in a range of +/- 10 cm about the fixation distance. Almost all cells showed binocular interaction. Neurons with balanced ocularity (approximately equal monocular responses) usually facilitated each other and were tuned to depth around the plane of fixation often with inhibitory flanks nearer and further. Neurons with unbalanced ocularity either inhibited each other or had asymmetric depth sensitivity profiles, i.e. activation by stimuli in front and suppression by stimuli behind the fixation plane (near cells) or vice versa (far cells). Thus striate and prestriate cortex of the monkey contains four subsets of binocular cells which may contribute to depth perception.


[Androgenic function of the testes in children and adolescents with cryptorchism]. Androgenic function of the testes was studied in children and adolescents suffering from cryptorchism. Information on this problem is scant and controversial. The most sensitive radioimmunological methods of testosterone determination and functional test with chorionic gonadotropin were used in this work. Disturbances in adrogenic function are present in a number of cases as soon as the first years of life. These disturbances are intensified with the advance of age, and become particularly pronounced in bilateral and abdominal cryptorchism.


Stereopsis and the random element in the organization of the striate cortex. Receptive field position and orientation disparities are both properties of binocularly discharged striate neurons. Receptive field position desparities have been used as a key element in the neural theory for binocular depth discrimination. Since most striate cells in the cat are binocular, these position disparities require that cells immediately adjacent to one another in the cortex should show a random scatter in their monocular receptive field positions. Superimposed on the progressive topographical representation of the visual field on the striate cortex there is experimental evidence for a localized monocular receptive field position scatter. The suggestion is examined that the binocular position disparities are built up out of the two monocular position scatters. An examination of receptive field orientation disparities and their relation to the random variation in the monocular preferred orientations of immediately adjacent striate neurons also leads to the conclusion that binocular orientation disparities are a consequence of the two monocular scatters. As for receptive field position, the local scatter in preferred orientation is superimposed on a progressive representation of orientation over larger areas of the cortex. The representation in the striate cortex of visual field position and of stimulus orientation is examined in relation to the correlation between the disparities in receptive field position and preferred orientation. The role of orientation disparities in binocular vision is reviewed.


Binocular visual processing in the owl's telencephalon. Single neurons recorded from the owl's visual Wulst are surprisingly similar to those found in mammalian striate cortex. The receptive fields of Wulst neurons are elaborated, in an apparently hierarchical fashion, from those of their monocular, concentrically organized inputs to produce binocular interneurons with increasingly sophisticated requirements for stimulus orientation, movement and binocular disparity. Output neurons located in the superficial laminae of the Wulst are the most sophisticated of all, with absolute requirements for a combination of stimuli, which include binocular presentation at a particular horizontal binocular disparity, and with no response unless all of the stimulus conditions are satisfied simultaneously. Such neurons have the properties required for 'global stereopsis', including a receptive field size many times larger than their optimal stimulus, which is more closely matched to the receptive fields of the simpler, disparity-selective interneurons. These marked similarities in functional organization between the avian and mammalian systems exist in spite of a number of structural differences which reflect their separate evoluntionary origins. Discussion therefore includes the possibility that there may exist for nervous systems only a very small number of possible solutions, perhaps a unique one, to the problem of stereopsis.


The development of the binocular depth cells in the secondary visual cortex of the lamb. In most respects, the response properties of cells in the secondary visual cortex of the newborn lamb were indistinguishable from those in the adult. The cells were sharply selective to orientation; the orientation preferences were the same in each eye, and they varied systematically as the electrode penetrated the cortex. The receptive-field organization did not differ noticeably from that in adults, and complex, hypercomplex, and a few simple cells were all observed. The ocular dominance distribution was similar to that in the adult. Most importantly, binocular cells were found with disparate receptive fields even in newborn, visually inexperienced animals. As in the adult, the disparities were largely horizontal, and they appeared to be arranged in columns. Many of the cells responded preferentially to a binocular stimulus at a particular disparity setting (often approximately zero), but unlike those in the adult almost all the binocular cells in the newborn lamb would also respond monocularly, and the enhancement at the optimal disparity was less than in the adult. The full development of binocular selectivity took several weeks, and was blocked by binocular deprivation. We conclude that the basic wiring of stereoscopic mechanisms is innate, but the development of mature binocular interaction may depend on an adaptive process which makes use of the visual information received during binocular stimulation.


Stereo vision and isoluminance.

Stereo vision and isoluminance. Recent experiments have shown that stereo depth is given by fusion of illusory ('cognitive') contours. They occur across quite large gaps in figures, when these gaps are unlikely and form the shape of a probable (nearer) masking object or masking feature. Implications are that: (a) clearly defined contours and regions of brightness difference can be produced as postulates from sensory evidence, which may be surprising absence of stimulation; (b) each eye-system can derive its own postulates, or hypotheses, which (c) can be combined to give stereo vision. It has been shown that random-dot stereo depth does not occur when there is colour contrast but no brightness difference between the dots and their background. This we have confirmed by using a new technique for producing isoluminant pictures, of any complexity, with exact registration for any two colours. With this technique, we find large displacements of narrow borders bounding regions that are shifted across isoluminance. These displacements, which are clearly seen as movements, occur with or without colour differences. The direction of shift depends on whether the narrow border is light or dark. It is found that these dramatic shifts do not - when produced in opposite directions to the two eyes and fused - produce stereo depth. It is concluded, following Julesz's paradigm, that these contour displacements have their neural orgin not retinally, but after stereo fusion. Experiments combining the 'cognitive contours' stereo depth with isoluminance are described.


The development of stereoscopic mechanisms in the visual cortex of the cat. It is argued that those neural systems (such as that responsible for stereoscopic vision) that have the greatest precision of operation are the most likely, during their developmental construction, to take advantage of infromation supplied by their own input. There is evidence that binocularly driven neurons in the kittens's visual cortex do indeed become modified in their synaptic organization during early visual experience in a manner that enhances the specificity of binocular interaction and ensures that the ranges of positional and orientational disparities of the receptive fields, within limits, become matched to the nature of the actual stimulation encountered by the animal.