Competence for genetic transformation in pneumococcus depends on synthesis of a small set of proteins. In bacterial genetic transformation the uptake of DNA and its integration into the resident chromosome is dependent on a special cellular state, termed competence. In those species where appearance of competence has been studied, specific (but often poorly defined) growth conditions lead to a simultaneous development of competence in a substantial fraction of the cells in a culture. In Bacillus subtilis, and in Haemophilus species, competence appears in the stationary phase of growth or in certain other growth-limiting conditions. Streptococcus pneumoniae (pneumococcus) is perhaps unusual in that virtually all cells of a culture become competent, for a short period at a specific cell density during logarithmic growth, without perturbing the growth rate. The synchronous appearance of competence in pneumococcal cultures results from an autocatalytic effect of a small protein released by the cells that induces competence. The response to competence factor has been shown to require protein synthesis. We report here additional information on the nature of competence in pneumococcus: pulse-labelling studies show that for the brief period of competence protein synthesis is restricted to a few specific polypeptides.


Specific labelling of postsynaptic alpha 1 adrenoceptors in rat heart ventricle by 3H-WB 4101. The alpha-adrenoceptor ligand, 3H-WB 4101 binds to a single population of independent sites in the rat heart ventricle. These sites are not affected by chemical sympathectomy with 6-hydroxydopamine and thus appear to be located postsynaptically. The relative order of potencies for displacement of 3H-WB 4101 binding:prazosin greater than phentolamine greater than yohimbine, is characteristic of that of the alpha 1 type of adrenoceptors. In heart ventricle 3H WB-4101 thus seems to label specifically postsynaptically located alpha 1-adrenoceptors. The significance of the specificity of this ligand is discussed with relevance to its use in the central nervous system.


Modulatory role of catecholamines on tyrosine hydroxylase induction. The possible modulatory role of cytoplasmic catecholamines on tyrosine hydroxylase induction was studied. Rat superior cervical ganglia were kept in organ culture and after 48 h tyrosine hydroxylase activity was determined. Exposure to 10(-4) M carbachol during 4 h almost doubled the control activity. Incubation with 10(-5) M noradrenaline or 10(-5) M dopamine impaired the carbachol-mediated induction of the enzyme. This effect was not blocked by 10(-7) M  propranolol, 2.4 X 10(-6) M haloperidol or 3.1 X 10(-6) M phentolamine. Inhibition of monoamine oxidase activity by 5.1 X 10(-4) M pargyline inhibited the effect of carbachol. When the pool of endogenous catecholamines was decreased by alpha-methyl-p-tyrosine, carbachol induced tyrosine hydroxylase to the same extent as in non-depleted ganglia. It is suggested that the long-term regulation of tyrosine hydroxylase is modulated by a strategic cytoplasmic pool of catecholamines.


Peritoneal clearances with three types of commerically available peritoneal dialysis solutions. Effects of pH adjustment and intraperitoneal nitroprusside. Peritoneal clearances were measured in multiple patients with different types of peritoneal dialysis solution to assess the effects of pH, choice of buffer anion (acetate versus lactate), and the effects of nitroprusside (a vasodilator) in combination with different buffer anions and varying pH. The studies show no differences in peritoneal clearances at very low solution pH (less than 6 as is commonly available) as compared to a pH nearer to 7 or above. There were no diffences between solutions with acetate as compared to those with acetate. Nitroprusside significantly increased clearances in all solutions to a similar extent.


Tubular function in adult polycystic kidney disease. Various tubular functions were assessed in 10 patients with polycystic kidney disease (PKD). Three relatively unique abnormalities were apparent in many of these patients -- an inability to maximally concentrate urine, a decrease in ability to lower urine pH after acute acid challenge, and an inability to excrete adequate amounts of ammonium during persistent acid challenge. The defects in urinary acidification and ammonium excretion in PKD have not been previously described.


Abnormalities of neurotransmitter enzymes in Huntington's chorea. The activities of L-glutamate decarboxylase (GAD), GABA-transaminase (GABA-T), choline acetyltransferase (CAT), and cysteic and cysteinesulfinic acids decarboxylase (CAD/CSAD) in putamen and frontal cortex in both Huntington's chorea and normal tissues were measured. The greatest difference between Huntington's and normal tissues occurred in putamen, in which the apparent CSAD activity was reduced by 85%, while no difference was observed in frontal cortex. GAD, CAD, and CAT activities were also reduced in putamen by 65%, 63%, and 42%, respectively (P less than 0.05). Slight reduction in the enzyme activities was also observed in frontal cortex. However, these reductions appeared to be statistically insignificant (P greater than 0.05 in all cases). GABA-T showed little difference in both putamen and frontal cortex in Huntington's chorea and normal tissues. GAD and GABA-T from Huntington's tissues were indistinguishable from those obtained from normal tissues by double diffusion test and by microcomplement fixation test, which is capable of distinguishing proteins with a single amino acid substitution. Furthermore, the similarity of the complement fixation curves for GAD from Huntington's and normal tissues suggests that the decrease in GAD activity is probably due to the reduction in the number of GAD molecules, presumably through the loss of neurons, and not due to the inhibition or inactivation of GAD activity by toxic substances which might be present in Huntington's chorea.


Stimulation by subsynaptosomal fractions of transmitter efflux from plain synaptic vesicle fraction. The effects were investigated of purified subsynaptic fractions on the efflux of radioactivity from a plain synaptic vesicle fraction which had incorporated [3H]dopamine. About 50% of the radioactivity incorporated into the plain vesicles (120 microgram protein) was liberated on exposure to purified synaptic membranes (30 microgram protein). The synaptic membrane-dependent efflux appeared to depend on both adenosine triphosphate and divalent cations, especially Ca2+. Of the sub-cellular fractions used, the heavy microsomal fraction showed the same effects as the synaptic membrane fraction. Purified synaptic junctions exhibited the strongest stimulating effects: the efflux was 2 times greater than that observed with synaptic membranes. The stimulating effects of myelin were less than one-seventh of those of synaptic junctional fraction. These observations may indicate that the transmitters are liberated by interaction of vesicle membrane with synaptic membrane in the presence of ATP and divalent cations.


In vitro antimicrobial susceptibility of Streptococcus pneumoniae in New Zealand. Ninety-seven isolates of Streptococcus pneumoniae referred to the National Health Institute between January 1976 and March 1978 were tested for their susceptibility to 10 antimicrobials. All were susceptible to penicillin, erythromycin, chloramphenicol, vancomycin, clindamycin, cephalothin and rifampicin. Resistance to tetracycline was found in 9.3 percent of the isolates, and 9.7 percent were resistant to a combination of sulphamethoxazole and trimethoprim.


Electroretinogram in general medicine.

Electroretinogram in general medicine. The interest of the usage of the electroretinogram in various fields of general medicine is discussed, with particular regard to endocrinology, ionic changes and neurology. A review from the relevant literature and original contributions from the author's laboratory are reported in detail.


Red cell oxygen affinity, hemoglobin type, 2,3-diphosphoglycerate, and pH as a function of fetal development. Studies were carried out on fresh cord blood obtained at delivery from nonstressed normal fetuses ranging from 24 to 42 weeks of gestation, to determine the relationship of 2,3-diphosphoglycerate (DPG), the intracellular red cell and extracellular pH, and the proportions of adult and fetal hemoglobin in regulating the position of fetal red cell oxygen affinity in utero. There was a significant positive correlation between P50 and gestational age (r = .62, P less than .001), the linear regression increased from 17.8 to 22.5 mm Hg. There was also a significant positive correlation between P50 and the percentage of adult type hemoglobin (HbA) (r = .67, P less than .001). In contrast gestational age had no effect of 2,3-DPG levels, the mean and SD was 14.86 +/- 2.04 mol/gm of Hb or delta pH between plasma and red cell, the mean was 0.187 +/- SD 0.032. However, there was a significant negative correlation between the intraerythrocyte hydrogen ion concentration and DPG level (r = .5, P less than .025). It is concluded therefore that the decrease in fetal oxygen affinity as gestation progresses is related mainly to the increase in the amount of HbA and the levels of DPG or delta pH between plasma and red cells are not a function of gestational age.


[Polyarteritis nodosa with ureteric stenosis. Two cases (author's transl)]. In two cases, surgical exploration fully confirmed that ureteric stenosis was related to PAN. There are four cases of this association in the litterature but it is probable that the frequency of such stenosis is underestimated: amongst 75 patients being treated for PAN in our department, only 11 underwent intravenous urography, 10 being abnormal.


[Shy and Drager syndrome. Physiopathological and pharmacological approach based upon one case (author's transl)]. The authors report a new case of Shy and Drager syndrome characterized by the severity of the extrapyramidal signs as well as that of orthostatic hypotension and urinary dysfunction. Peripheral adrenergic disturbance was proven, associated with an abnormality of the renin-angiotensin system. The authors describe the various drugs tried experimentally in treatment of the three main symptoms of the disease. A combination of Trihexyphenidyl and Dibenzepine finally appeared to be the most effective. Six months later, there remained a marked improvement in extrapyramidal signs and orthostatic hypotension. By contrast there was no improvement in urological symptoms.


The temperature and pH dependence of conformational transitions of the chromatin subunit. Hydrodynamic, spectroscopic, and chemical crosslinking studies on monomer chromatin subnits are reported as a function of ionic strength, pH, and temperature. In earlier studies, two salt-dependent conformational transitions were described (Gordon et al., Proceedings of the National Academy of Science, 75, 660, 1978). Transition one occurred between 0.7 and 2.0 mM ionic strength and transition two occurred between 5.0 and 11.0 mM ionic strength. Crosslinking at 11 mM ionic strength with formaldehyde suppressed both transitions. In this communication we report that the second transition was characterized by changes in the circular dichroism spectra in the 260--320 nm region as well as by changes in the hydrodynamic properties. As the ionic strength was increased from 5.0 to 11.0 mM, [theta]282 decreased from 2000 TO 1500 DEG CM2/DMOLE AND [THETA]295 decreased from 0 to -400 deg cm2/dmole. Both transitions occurred in the pH range from pH 6.0 to 9.2. At pH 5.0, the two ionic strength-dependent transitions were no longer observed and the characteristic changes in the circular dichroism spectra were suppressed. The spectra of the monomer subunits at pH 5.0 showed only small changes with ionic strength and resembled the spectra of the subunits at 11 mM ionic strength above pH 6.0. In order to characterize the transitions in thermodynamic terms an ionic strength near the midpoint of each transition was selected. Then, changes in s20,w and D20,w were measured as a function of temperature. These data allow an estimation to be made of the enthalpies and entropies of the transitions.


Complexes formed by (pyrimidine)n . (purine)n DNAs on lowering the pH are three-stranded. (Pyrimidine)n . (purine)n DNAs of repeating sequences form a distinctive complex on lowering the pH below 6. Previously this complex was thought to be tetra-stranded. The present work is inconsistent with this view, and four lines of evidence show that the complex consists of a triplex together with a poly d(purine) possessing secondary structure. Formula: (see text). (a) S1 nuclease digestion leads to degradation of 50% of the poly d(purine) content of the pH 5-induced complex. (b) Buoyant density studies demonstrate that there is no interaction between the triplex and added free poly d(purine) and also that the complex formed from duplex DNA contained poly d(purine) which is free to form a triplex on addition of an appropriate poly d(pyrimidine) in the correct stoichiometry. (c) The hyperchromic shifts of the triplex and poly d(purine), upon melting, are mutually independent. (d) The circular dichroism spectrum of the complex is simply the weighted average of a triplex together with a free poly d(purine). The triplexes have tm's approximately 20 degrees higher than the corresponding duplexes under comparable conditions and they are extremely resistant to various deoxyribonucleases; properties which may prove useful for their isolation from natural sources.


Specificity and mode of cleavage of the pH 4.0 endonuclease from adenovirus type 2 - infected KB cells. Adenovirus type 2 or lambda DNA was digested with the pH 4.0 endonuclease, purified from adenovirus 2-infected KB cells. The enzyme produces a limit digest of approximate size in the range of 140-210 base pairs long. The termini of the DNA fragments generated by the endonuclease digestion had 3'-P and 5'-OH groups. The 3' and 5' end groups of the products were analyzed. Our data indicate that 3' end group was a purine (68-76%), dA occuring about twice the frequency of dG. The 5' end group was either dG or dC with equal frequency. Data obtained by treatment of the 5' labeled endonuclease product of lambda DNA with single-strand specific S1 nuclease from Asperigillus oryzae or exonuclease VII from Escherichia coli indicated that the majority of the products had a short 5' protruding ends. The mode of cleavage of this endonuclease seems to be through initial formation of several single-strand breaks with some base specificity. If these breaks are at close proximity on opposite strands, double-stranded fragments with protruding ends are generated.


Oral complications of bone marrow transplantation in adults with acute leukemia. In recent years bone marrow transplantation has become increasingly feasible for treating adult acute leukemia unresponsive to chemotherapy. However, the technique is not without significant intrinsic morbidity. The mouth is a singularly sensitive reflector of the cytotoxic, infectious, and hemorrhagic complications and of the graft-vs-host reactions associated with bone marrow transplantation in refractory acute leukemia.


Acid-base changes associated with respiratory acclimatization to altitude. The respiratory changes associated with chronic hypoxia are described. The possible biochemical mechanisms which are responsible for the changes in control of ventilation are discussed and relevant experimental evidence assessed.


[Restoration of enzyme induction, reduced as a result of long-term cortisol administration, in rat liver]. Restoration of tyrosinamine transferase (TAT) with cortisol in the rat hepatocytes after the cessation of prolonged (for many days) administration of this hormone was investigated. The effect of the liver regeneration and insulin administration on this process was also studied. In single cortisol administration the TAT activity rose 5-fold; the induction response decreased after 21 days of daily administration. The TAT induction in response to cortisol administration was restored completely only on the 25th--30th day after the cessation of this hormone injection. A three-day insulin administration led to the restoration of TAT induction in response to cortisol administration. The process of the liver regeneration during the first 24 hours after partial hepatectomy induced TAT in the cells of both control animals and those given cortisol for prolonged periods; besides, it aided restoration of the induction response to cortisol administration.


Neurological features of polyarteritis nodosa. A series of 20 cases of polyarteritis nodosa (PAN) is presented. Clinical features of 2 cases are described in more detail to illustrate the most common neurological complications. PAN is an uncommon disease but one which usually presents with some form of neurological disturbance, often a mononeuritis multiplex or a symmetrical polyneuropathy. Diagnosis requires a high degree of clinical suspicion as serological tests are at best non-specific, and absolute biopsy proof often requires examination of multiple sites. Early diagnosis is important, as treatment with corticosteriods usually induces symptomatic relief and provides a better chance of long term survival. If an acute remission is obtained the patient not only should have a good quality of life but in a proportion of cases, where the remission is prolonged, steroid therapy may be ceased.


Mass balance of base equivalents during hemodialysis: importance of organic acid anions. Acid-base changes during hemodialysis cannot be calculated solely from the balance of acetate and bicarbonate. Organic acid losses strongly influence acid-base balance during hemodialysis. Changes in organic acid concentrations might alter acid-base balance in hemodialysis patients.


Active transport of calcium in Neurospora plasma membrane vesicles. Functionally inverted plasma membrane vesicles isolated from the eukaryotic microorganism Neurospora crassa catalyze Mg2+/ATP-dependent Ca2+ uptake. Inhibitors induced efflux studies and isotope-exchange experiments indicate that the Ca2+ is accumulated inside the vesicles against a concentration gradient of about 40-fold, and that the majority of the transported Ca2+ is present essentially in free solution. Comparisons of Mg2+/ATP-driven 45Ca2+ uptake and [14C]SCN-uptake with respect to the Mg2+/ATP concentration dependence, the effects of inhibitors, and the nucleotide and divalent cation specificities indicate that the energy for Ca2+ accumulation is derived from ATP hydrolysis catalyzed by the electrogenic plasma membrane ATPase. Energized Ca2+ uptake is stimulated by the permeant anion SCN- to a degree that varies reciprocally with the ability of this anion to dissipate the membrane potential, and is inhibited by K+ in the presence of nigericin. All of these data point to the conclusion that the active transport of Ca2+ across the Neurospora plasma membrane takes place via a Ca2+/H+ antiporter, which functions to pump Ca2+ out of the intact cell.


Urinary acidification in turtle bladder is due to a reversible proton-translocating ATPase. Adverse proton electrochemical gradients (delta muH) applied across the turtle urinary bladder decrease active H+ transport in this epithelium. A delta muH of 180 mV abolishes both transport and its tightly coupled metabolic reaction. Larger gradients should, in theory, reverse the direction of H+ transport and the metabolic reaction leading to synthesis of ATP if the pump is an ATPase, or cause an increase in the oxidized state of a redox pair if it is a redox pump. To distinguish between these two possibilities, we measured ATP levels in epithelial cells that were poisoned to inhibit cellular mechanisms of ATP synthesis. At delta muH of 120 mV or less no ATP synthesis was found. At delta muH of greater than 120 mV there was a linear increase in ATP synthesis. Dinitrophenol, a H+ carrier, prevented synthesis at delta muH of 310 mV. Dicyclohexylcarbodiimide, an inhibitor of H+ transport that works at the cell surface, prevented ATP synthesis at delta muH of 310 mV. These results demonstrate that a reversible proton-translocating ATPase in the mucosal border of the bladder is the H+ pump responsible for urinary acidification.


Uptake and accumulation of putrescine and its lethality in Anacystis nidulans. The rate of uptake of putrescine by Anacystis nidulans has been shown to depend on the external pH and the extracellular concentration of putrescine. Accumulation of exogenous putrescine was also proportional to the concentration of putrescine in the medium, suggesting that putrescine uptake was not subject to cellular regulation. An equation was derived to test the hypothesis that putrescine accumulation was due to ion trapping. Comparison of the predicted and observed intracellular concentrations of putrescine under various conditions showed a close correlation in support of the hypothesis of ion trapping. Under conditions leading to cell death (e.g., 150 microM putrescine, pH 9.8), the correlation did not hold as a result of leakage of accumulated putrescine.


Testosterone and its precursors and metabolites enhance guanylate cyclase activity. Both testosterone and cyclic GMP stimulate DNA synthesis. Because cyclic GMP and testosterone seem to have similar actions, the objective of this investigation was to determine if testosterone and its precursors might have part of their mechanism of action through stimulation of guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2], the enzyme that catalyzes the formation of cyclic GMP from GTP. The precursors--namely, progesterone, pregnenolone, 17 alpha-progesterone, 17 alpha-hydroxypregnenolone, androstenedione, and dehydroepiandrosterone--caused a 2- to 3 1/2-fold enhancement of guanylate cyclase activity in rat liver, kidney, skeletal muscle, and ventral prostate at a concentration of 1 microM. These precursors are generated from cholesterol, which had no effect itself on guanylate cyclase activity. Testosterone, 19-nortestosterone, 17-methyltestosterone, and 5 alpha-dihydrotestosterone enhanced guanylate cyclase activity 2- to 5-fold in the same tissues at 1 microM. Etiocholanolone, androsterone, and epiandrosterone, metabolites of testosterone metabolism, enhanced guanylate cyclase activity 1 1/2- to 2-fold at this same concentration. Dose-response relationships revealed that testosterone and its precursors and metabolites had their maximal effect at 1 microM but still had some effect at 0.001 microM. The data in this investigation suggest that the guanylate cyclase-cyclic GMP system plays a role in the mechanism of action of testosterone and its precursors.


The gamma-aminobutyric acid system in rabbit retina: localization by immunocytochemistry and autoradiography. The localization of gamma-aminobutyric acid (GABA) neurons in the rabbit retina has been studied by immunocytochemical localization of the GABA-synthesizing enzyme L-glutamate decarboxylase (L-glutamate I-carboxy-lyase, EC 4.1.1.15) and by [3H]GABA uptake autoradiography. When Triton X-100 was included in immunocytochemical incubations with a modified protein A-peroxidase-antiperoxidase method, reaction product was found in four broad, evenly spaced laminae within the inner plexiform layer. In the absence of the detergent, these laminae were seen to be composed of small, punctate deposits. When colchicine was injected intravitreally before glutamate decarboxylase staining, cell bodies with the characteristic shape and location of amacrine cells were found to be immunochemically labeled. Intravitreally administered [3H]GABA produced a diffuse labeling of the inner plexiform layer and a dense labeling of certain amacrine cell bodies in the inner nuclear layer. Both immunocytochemical and autoradiographic results support the notion that certain, if not all, amacrine cells use GABA as their neurotransmitter.


Occurrence and role of tightly bound adenine nucleotides in sarcoplasmic reticulum of rabbit skeletal muscle. Freshly isolated sarcoplasmic reticulum vesicles contain 0.05 mol of tightly bound ADP and 0.03 mol of tightly bound ATP per mol of Ca2+, Mg2+-ATPase (ATP phosphohydrolase, EC 3.6.1.3). These values were increased to 0.1-0.2 mol ADP and 0.2-0.3 mol ATP per mol of ATPase after incubation of vesicles in the presence of MgATP and Ca2+ at 25 degrees C and pH 7.0. Half-maximal enrichment of tightly bound nucleotides was obtained with 2.5 mM ATP and 0.32 microM free Ca2+. Uncoupling of calcium transport from ATPase activity by mild acidic conditions or with ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid at pH 7.0 decreased the ability of the membranes to be enriched with tightly bound nucleotides and also decreased the content of tightly bound nucleotides of previously enriched membranes. Tightly bound [3H]nucleotides could only be partially displaced by reincubation under enrichment conditions. Tightly bound nucleotides are associated with energized calcium translocation but do not appear to be directly involved in the catalytic cycle.


Mechanism of toxicity of putrescine in Anacystis nidulans. Putrescine is lethal to the cyanobacterium Anacystis nidulans at extracellular pH values at which significant concentrations of the nonprotonated diamine rapidly diffuse into the cell and accumulate as the charged form. Although over 98% of the accumulated putrescine is not metabolized, a small fraction is rendered trichloroacetic acid-insoluble, and about 90% of this is bound as putrescinie to proteins and cell structures. Various synthetic functions were studied in the presence of a bacteriostatic (40 microM) and a bacteriocidal (150 microM) concentration of putrescine at pH 9.5. Under lethal conditions, protein synthesis was completely inhibited after 45 min and CO2 fixation after 100 min, whereas nucleic acid synthesis was less affected. Spermidine was lost from the cell and its synthesis was arrested. These functions were much less inhibited at 40 microM putrescine. Ribosomes from putrescine-killed cells were found to be irreversibly dissociated into 30S and 50S subunits. Some putrescine (1-4 molecules) cosedimented with each subunit.


UV-endonuclease from calf thymus with specificity toward pyrimidine dimers in DNA. We describe the partial purification of an endonuclease from calf thymus that nicks phage PM2 DNA irradiated with UV doses producing only a few pyrimidine dimers per molecule. It has much less activity on DNA that has been subjected to enzymatic photoreactivation after UV irradiation. The calf thymus endonuclease is different from other mammalian UV-endonucleases so far described in that it seems to be dimer specific. The enzyme is stimulated by Mg2+ and is inactive in the presence of EDTA. It binds to UV-irradiated DNA-Sepharose from which it is released by low concentrations of KCl. Gel filtration data indicate that the endonuclease may belong to a high molecular weight protein or protein complex. The enzyme is very labile and freezing increases its lability.


Detection of risk of cancer to man.

Detection of risk of cancer to man. Epidemiology can pick out large-scale determinants of human cancer, such as smoking. Also, epidemiology can pick out carcinogens such as asbestos to which groups of perhaps a few hundred or a few thousand workers have been heavily exposed for decades. However, if highly exposed groups cannot be studied then epidemiology cannot recognize carcinogens which, although perhaps widely distributed, produce only a small percentage increase in particular cancers. Almost all of the environmental pollutants that can affect human cancer incidence will do so only to a very minor extent, at the levels to which we are currently exposed. For this reason, and also because it is often difficult to define an exposed and an unexposed group which do not differ in other ways as well, it will almost always be impossible to do anything epidemiologically except to set a very crude upper limit on their likely hazards. The only way, therefore, to get any direct estimate of these hazards is by laboratory studies of the effects of high doses on various model systems. For this and for other reasons, it would be highly desirable to have good laboratory models for human carcinogenesis. The characteristics required of satisfactory laboratory systems are reviewed, and it is argued that systematic errors may arise unless one studies epithelial cells from large, long-lived species under conditions of chronic, low-dose exposure to noxious test agents in conjunction with standard chronic doses of agents which may be synergistic with the test agents. (Carcinogenic mutagens may be synergistic with carcinogenic non-mutagens.) For reasons of expense and speed, such studies must be done in vitro. If such in-vitro systems can be developed, either by using tissue explants or cell cultures, an important criterion which they will have to satisfy to be trusted will be that under chronic exposure the rate of transformation should be proportional to something like the fourth power of exposure duration. This paper chiefly reviews the reasons for choosing these specifications for a trustworthy in-vitro model for human carcinogenesis.


Carcinogen prediction in the laboratory: a personal view. Although carcinogens can be divided into various categories, i.e. viruses, physical agents and synthetic and naturally occurring chemicals, it is the latter that give rise to the greatest concern because of their number, quantity and distribution. Present methods of testing chemicals for potential carcinogenicity rely in the main on administration of these at maximally tolerated dose levels to animals, usually rodents, for the animals' lifetime. Such tests would be economically impractical for all chemicals to which man is exposed. New methods have recently been introduced to screen large numbers of chemicals quickly and cheaply which rely on the unifying hypothesis that all carcinogenic chemicals are electrophiles or must be converted to such by metabolism. These methods will be reviewed and compared with traditional methods of carcinogenicity testing, particularly as to their role in attempting to predict hazard to man.


Cardiovascular disease and trace metals. Cardiovascular disease is a major cause of morbidity and mortality in the U.K. and other developed countries. In the U.K., mortality from coronary heart disease has increased progressively over the past 25 years, particularly in males. This paper examines the possible role of trace metals in the development of cardiovascular disease, with particular reference to the effects of cobalt, cadmium and lead in myocardial disease, atherosclerosis and hypertension. It is concluded that cobalt is an unimportant factor in community levels of cardiovascular disease, that cadmium has striking effects on blood pressure in animals and that there is some evidence for an association between environmental lead and high blood pressure.


Record linkage and the identification of long-term environmental hazards. The long-term effects of toxic substances in man that have been discovered so far have involved gross relative risks or bizarre effects, or have stumbled upon by chance or because of special circumstances. These facts and some recent epidemiological evidence together suggest that a systematic approach with better methods would reveal the effects of many more toxic substances, particularly in manufacturing industry. Record linkage is a powerful tool because it makes possible the correlation of indicators of exposure with indicators of the biological effect of such exposure in the same persons or in their progeny even after considerable periods of time have elapsed. A system of linked records exists in England and Wales which is at present used by research workers to follow up samples of persons defined in various ways, e.g. in respect of exposure to a suspected toxic factor. In this way hypotheses about substances causing cancer or other lethal effects can be tested. It is suggested that there are two additional ways in which record linkage techniques could be used to identify substances with long-term toxic effects: the first would be by setting up a register of women employed in industry during pregnancy and linking this register to records of the occurrence of congenital malformations and of stillbirth or death in their children; the second would be to follow samples of workers in manufacturing industry, notably those engaged in the manufacture of products from raw materials including the chemical industry, to death and to the development of cancer. Regular analyses of material from these two systems of linked records would provide the basis for a monitoring system for certain gross effects of long-term toxic substances in man. There are two principal obstacles to further progress in this field. The first is the lack of a clear statement of public policy concerning the issues of confidentiality and informed consent in the use of identifiable personal records for medical research. A settlement is needed which defines the proper limits of their use in the interests of health with safeguards to privacy. The second obstacle is a lack of resources to improve the quality, accessibility and organization of the appropriate data.


Pollution of the sea and its effects.

Pollution of the sea and its effects. Marine pollution has been studied under the following groupings of effects; harm to living resources, hazards to human health, reduction of amenities and interference with other users of the sea. This paper is concerned mainly with the first two categories and their interrelation. Apart from certain seabirds affected by oil, the major stocks of marine animals show no evidence of reduction by pollution. Pollution effects are generally insignificant in relation to other factors governing reproductive success, survival, growth and population size. Even in the North Sea, which has received a greatly increased pollution load during the last three decades, both total production of fish and catch per unit of effort (a measure of abundance) of cod, haddock and plaice increased during the 20 years 1950--69. Very recent decreases have been due to over-exploitation but, except in certain estuaries and immediate coastal waters, direct damage by pollution to marine populations and ecosystems is not evident. Pollution effects can, however, be detected by chemical analysis. The paper examines human health risks arising in the marine environment, particularly from contaminated seafood, especially in relation to sewage pollution, metals such as mercury, cadmium and lead, synthetic organic substances and oil.


Hazards from chemicals: scientific questions and conflicts of interest. All substances are toxic when the dose is large enough. In order to regulate the use of chemicals, we need to measure the level at which toxic effects are found. Epidemiological evidence suggests that present levels of chemical use do not lead to widespread harmful contamination of the human environment. For chemicals, most of the problems of toxicity are found in the workplace, while the population at large gets most of its toxic effects from voluntary exposure to substances such as tobacco smoke and ethanol. The prevention and control of toxic effects depends on a series of steps. This begins with measurement of toxicity in model systems, such as laboratory animals, and the estimation of the likely exposure of workers or consumers. Reliable extrapolation of information gathered from animals to the diverse and biochemically differing human population depends on understanding mechanisms of toxic effects. The toxic effect and mechanisms of action of substances such as carbon tetrachloride or paracetamol have been extensively investigated, and our ability to predict toxicity or develop antidotes to poisoning has had some success, but epidemiology is still an essential part of assessment of toxic effects of new chemicals. The example of phenobarbitone shows how animal experiments may well lead to conclusions which do not apply to man. After measurement of toxicity and assessment of likely hazards in use comes the final evaluation of the use of a chemical. This depends not only on its toxicity, but also on its usefulness. The direct effects on health may be small in comparison with the indirect advantageous effects which a useful substance such as vinyl chloride may bring. The assessment of risks and benefits of new chemicals can be partly removed from a political style of discourse, but the evaluation of the relative weight to be attached to these risks and benefits is inescapably political. The scientific contribution must be to allow the debate to take place in the light of maximum clarity of information about the consequences of use of chemicals.


Hazards to wintering geese and other wildlife from the use of dieldrin, chlorfenvinphos and carbophenothion as wheat seed treatments. Chemical treatments of cereal seeds are used in the United Kingdom to prevent damage by a number of pests including the wheat bulb fly, which is a serious pest of winter wheat. The persistent organochlorine dieldrin was introduced in the 1950s as a seed treatment but caused the death of large numbers of grain eating birds and gave rise to unacceptable environmental contamination. The withdrawal of dieldrin as a seed treatment was made possible by the introduction of two less persistent organophosphate insecticides, chlorfenvinphos and carbophenothion. Although the introduction of these chemicals has been beneficial in reducing environmental contamination, some side-effects on wildlife have still been discernible and carbophenothion has now been withdrawn from use in Scotland owing to the deaths of wintering geese from carbophenothion poisoning. Subsequent laboratory studies have demonstrated that Anser geese are particularly susceptible to carbophenothion poisoning, and the underlying biochemical mechanism has been investigated. The fundamental problem of species variation in toxicity among the organophosphorus and carbamate pesticides which this investigation illustrates presents difficulties for registration authorities when they are considered for clearance for agricultural use. The implications of the environmental problems encountered with dieldrin, chlorfenvinphos and carbophenothion for the pre-clearance testing of new chemicals are discussed and the critical surveillance of the early years of commercial use of a chemical is recommended to support pre-clearance studies aimed at assessing the potential hazard to the environment.


The pattern of disease in the post-infection era: national trends. Information that can be used to assess trends in the health of the population is limited to the results of irregular surveys of nutritional status and 'I.Q.', to data obtained from the notification of infectious diseases, congenital malformations, blindness and other selected defects, and to mortality rates. The last have been recorded since 1841 and provide the most detailed and useful information, although they are often difficult to interpret because of changes in the nomenclature, classification, methods of diagnosis, and efficacy of treatment of disease states. In the last 40 years, mortality rates have shown progressive reductions at all ages which have continued past the time when improvements in the prevention and treatment of infectious disease might be expected to have produced their principal benefits. Notable differences have emerged between the sexes, the rates continuing to decline in women but remaining more or less stable for a period in middle-aged men. This difference can be attributed to sex differences in life-style, so that until recently the trends in women are likely to have been the better indicators of the effect of toxic agents in the environment. The available data are inadequate to assess possible effects such as alterations in behaviour, but are of some help in regard to teratogenicity and carcinogenicity.


Sources and extent of pollution.

Sources and extent of pollution. Before the sources and extent of pollution can be identified a definition of pollutants has to be agreed. The degree of disruption of natural cycles in the global ecosystem in terms of residence times and assimilation capacities must be assessed as a prerequisite of any system of control. The sources of man-made and naturally occurring chemicals that fall into this definition can be categorized and these are presented for reference. Specific examples of these categories are discussed in detail, e.g. sulphur dioxide, polychlorinated biphenyls and radioactive waste. Their distribution and dilution in the environment are governed by fluid mixing mechanisms. These can be modelled to allow prediction of effects at specific points taking into account disappearance by decay, chemical reaction and deposition. Reappearance through pathways which involve accumulation and remobilization can only be predicted when a complete scientific understanding of the mechanism has been established.


Epidemics of non-infectious disease.

Epidemics of non-infectious disease. Epidemics of non-infectious disease are often caused by exposure to industrial products, intermediates or by-products, either in the work-place or as a result of the contamination of a wider environment. Although the prime objective of research must be the recognition of the hazard and the evaluation of its magnitude so that illness may be prevented, close collaboration of clinicians, epidemiologists and toxicologists should lead to the acquisition of much knowledge of the mechanisms by which disease is caused. Catastrophes, though always regrettable, must be seen as experiments demanding careful analysis and exploitation. Many examples of different types of problem will be selected from the numerous epidemics from the time of the Schneeberg and Joachimsthal miners to the recent concern with contamination of the environs of Seveso by dioxin.


'Our load of mutation': reappraisal of an old problem. H. J. Muller, in a paper in 1950 entitled 'Our load of mutation', predicted the genetic decay of the human species due to increasing mutation pressure combined with relaxation of natural selection. In the meantime, much information on spontaneous and induced mutations in humans has been accumulated, and a reappraisal of Muller's conclusions gives a much less gloomy overall picture. However, a certain increase of malformation and disease can be predicted as a result of ionizing radiation and chemical mutagens. On the other hand, genetic counselling and antenatal diagnosis of genetic anomalies may help to keep the genetic risks within tolerable limits. Research on the biological conditions for the untoward effects of mutagenic chemicals considered necessary for the wellbeing of humans may also help to reduce genetic risks. The extent and kind of the risks as well as possibilities for prevention are discussed with a few examples.


Congenital malformations and other reproductive hazards from environmental chemicals. From a number of disasters which have already occurred throughout the world, it is known that the reproductive process in both animals and man may be severely affected by chemicals. The range of effects that might occur include not only foetal death or malformation, but also effects on the subsequent development, behaviour, intelligence and reproductive capacity of offspring which appear otherwise normal at birth. The special sensitivity of the foetus to some environmental carcinogens is also discussed. Some of the problems in screening for such effects in animals are mentioned along with the need for adequate monitoring programmes to detect reproductive toxicity both from industrial exposure to chemicals and from more general environmental exposure.


Synthesis of enkephalins by guinea-pig striatum in vitro. A method for obtaining incorporation of labelled amino acids into enkephalins of guinea-pig striatum in vitro and isolating the labelled enkephalins is described. The incorporation of [3H]tyrosine increases with time after a delay of 2 h. Cycloheximide added during this time, but not at later stages, inhibits incorporation. The results indicate that the enkephalins are produced locally, probably by ribosomal synthesis. The lag period may be due to the time required for the synthesis of precursors and their conversion to the enkephalins.


Suboesophageal neurons involved in head movements and feeding in locusts. The projections of nerves 6 and 7 of the locust suboesophageal ganglion (SOG) were stained by axonal filling with cobalt chloride. Nerve 6 contains two motoneurons which innervate neck muscles 50 and 51. Sensory neurons innervating hairs on the dorso-occipital region of the head also enter the ganglion through nerve 6 and terminate in a small bilateral plexus. The projections of the head hairs in nerve 6 do not overlap the arborizations of the motoneurons or the neurons of nerve 7, but lie in the same area as descending sensory neurons from wind-sensitive hairs of the front of the head. One branch of nerve 7 (7B) contains two fibres which innervate the salivary gland. These 'salivary' neurons (labelled SN1 and SN2) have their cell bodies in the ganglion. The second branch, 7A, contains sensory neurons from the submentum of the labium, which form four sensory plexuses, two dorsal and two ventral. The sensory plexuses from the submentum have specific regions of overlap with the salivary neurons and with the neck muscle motoneurons. We interpret these as indicating a flow of information from labial receptors signalling head and mouthpart movement to neurons involved in salivation and head movement. We further postulate that the anatomical separation of the various sensory plexuses is indicative of functional localization within the ganglion.


Optimum probabilistic processing in colour perception. I. Colour discrimination. A comprehensive account of wavelength discrimination and colour saturation discrimination is given in terms of optimum probabilistic signal detection. The theory is a logical deduction from statistical estimation theory of the visual estimate of the spectral parameters of the stimulus. In place of geometrical concepts associated with colour-space geometry, stimulus discriminability is determined by optimum decision rules given by likelihood ratio tests on statistics that are postulated for the trichromatic responses. The classical line element theory and its formulations are deduced to be discriminability measures between signals. The different mathematical forms of classical theory are shown to correspond to different statistical constraints.


Optimum probabilistic processing in colour perception. II. Colour vision as template matching. A statistical approach to account for psychophysical phenomena in human colour vision is presented. The central visual processor is viewed as an optimum recognizer of stochastic patterns supplied by the periphery. The processor makes an optimum estimate of the spectral parameters of the stimulus, given the wavelength filter characteristics of the periphery, the stochastic nature of the information and an internal template to which the external stimulus is matched. The estimate is constrained in ways inferred from empirical phenomena. Subjective brightness of monochromatic stimuli and related constant brightness manifolds in the colour space constitute the constraint for brightness estimation. Results analogous and in accord with those of earlier line element theories are obtained. The Bezold-Brücke hue shift constitutes the basic constraint for hue estimation. The hue estimate involves interrelation between the fields in the experiment. Similarities and differences both in basic conceptions and results introduced by the template matching notions are discussed.


The particulate basis of the resistance of a parasitoid to the defence reactions of its insect host. Small, membrane-bound particles, about 130 nm in diameter, have been isolated from that region of the genital tract of the ichneumon Nemeritis known as the calyx. These particles have been shown to possess the ability to confer resistance to encapsulation by Ephestia, the natural host of Nemeritis, upon a surface which would otherwise be encapsulated.


An insect glycoprotein: a study of the particles responsible for the resistance of a parasitoid's egg to the defence reactions of its insect host. A study has been carried out of the chemical composition and physical structure of small particles, 130 nm in diameter, isolated from the calyx of the ichneumon, Nemeritis canescens. The particles are vesicular, consisting of a densely-staining core surrounded by an outer membrane. The core of the particles is made up of protein and carbohydrate in the ratio 100:17; no nucleic acid was detected. The basic chemical subunit of the core of the particles appears to be a glycoprotein of molecular mass ca. 45 000. The basic structural subunit of the core, however, is a short, hollow cylinder, about 10 nm across. It seems likely that several chemical subunits make up one structural subunit, and that many structural subunits, surrounded by the membrane, make up a single particle.


The laminar organization of optic nerve fibres in the tectum of goldfish. Potentials in the tectum of large (12--20 cm) goldfish, evoked by stimulation of the optic nerve, were recorded extracellularly with double-barrelled electrodes (d.c., saline and a.c., Woods metal--Pt). Four fibre groups (E, M1, M2, M3) were recorded at latencies of approximately 2, 3, 5 and 8 ms after stimulation (conduction velocities of approximately 7, 5, 3 and 2 m/s). The same four groups were recorded from the optic nerve when the tectum was stimulated. The fastest fibre groups (E) did not give rise to a postsynaptic wave. Fibre groups M1, M2 and M3 gave rise to postsynaptic potentials which, following computation of their second spatial derivatives with depth, were found to have current sinks at depths of approximately 100-150 micrometers, 150--200 micrometers and 250--350 micrometers respectively. Thus the fastest conducting retinotectal fibres make their synapses most superficially, the opposite of the arrangement in the frog tectum. These postsynaptic waves fatigued at repetitive stimulus rates of 20--50 per second, and in twin pulses at interstimulus intervals of 10--15 ms; and they were reversibly blocked by topical application of pentobarbitol. The fibre potentials, however, were virtually undecremented under these conditions. To compare these electrophysiological findings with the anatomy, the cobalt procedure was used to visualize the profiles of the optic fibres in the various tectal laminae. A thick dense projection filled the superficial grey and white (s.g.w.) layer, and there was a thin satellite band just superficial to it. In addition, there were two deeper bands of sparse innervation, in the middle of the central grey zone (c.g.) and in the deep white (d.w.) layer. These bands were associated with the field potential sinks through lesions made with recording electrodes. The two deep bands correspond to the M3 fibre group. The dense s.g.w. innervation contains both the M1 and M2 fibre groups, the M1 just superficial to the M2. The fastest fibre group, E, which had no postsynaptic wave associated with it, persisted at least six weeks after retinal removal, and probably represents efferent cells with fibres projecting back through the optic nerve to the retina. Filled cell profiles could not be positively identified with the cobalt technique, but could be seen with the HRP technique, when the optic afferents were first allowed to degenerate. The filled cells were the pyramidals of the s.g.w. layer.


Lack of tolerance development to benzodiazepines in antagonism of the pentylenetetrazol discriminative stimulus. In an operant procedure of lever pressing on FR 10 schedule of food reinforcement male hooded rats were trained to respond on a lever on one side of a food cup following a 20 mg/kg pentylenetetrazol (PTZ) injection and to respond on a lever on the alternate side following a 1 ml/kg saline injection. Upon acquisition of the PTZ-saline discrimination, diazepam and chlordiazepoxide were tested and found to antagonize the PTZ discriminative stimulus. The animals were then injected with 10 mg/kg diazepam or chlordiazepoxide for ten consecutive days. New dose-response curves obtained following this treatment indicated that tolerance did not develop to the antagonism of the PTZ discriminative stimulus by these benzodiazepines.


Molecular mechanisms regulating the interactions between the benzodazepines and GABA receptors in the central nervous system. Using radioreceptor assay techniques to measure the kinetics of GABA and diazepam receptors, a relationship between GABA and benzodiazepine receptors has been firmly established in membranes of brain and neuroblastoma NB2a clonal cell lines. Occupancy of benzodiazepine receptors uncovers a new population of GABA receptors (GABA2 receptors) endowed with high affinity for GABA. Moreover, stimulation of GABA receptors increases the affinity of 1,4-benzodiazepine receptors for 1,4-benzodiazepines. This reciprocal interaction appears to be mediated by an endogenous regulatory protein (for details on this protein see [14 and 29]) which allosterically regulates GABA2 receptors while it competitively interacts with benzodiazepines for their specific binding sites. The rank order of potency of the various 1,4-benzodiazepines to block the action of this protein inhibitor on GABA receptors is related to their capacity to displace 3H-diazepam binding. These data suggest that the interaction between the 1,4-benzodiazepine receptors and the endogenous protein modulator of GABA2 receptors might play a role in the pharmacological action of the 1,4-benzodiazepines.


Modulation of benzodiazepine binding site sensitivity. Recent studies on agents which alter benzodiazepine binding site sensitivity in brain are described. GABAergic agonists enhance and antagonists inhibit binding to the brain specific benzodiazepine binding site, and the binding can be correlated with effects on neuronal cell firing in the dorsal raphe nucleus. Anions such as chloride, iodide and nitrite also enhance (3H)diazepam binding and this enhancement is consistent with their role in postsynaptic inhibition. Pretreatment of animals with the anticonvulsant, diphenylhydantoin, enhances both diazepam binding and the electrophysiological response to diazepam suggesting one possible locus for the anticonvulsant action of diphenylhydantoin in brain. Taken together, these results suggest the existence of a GABA/Cl- ionophore/BZ binding complex in brain. Preliminary results on the purification of the BZ component of this complex and fluorescent probes for its study are described.


CNS benzodiazepine receptors: physiological studies and putative endogenous ligands. The recent demonstration of benzodiazepine receptors in the mammalian CNS has provided new information on the mechanism of action of this important class of drugs. In addition, the presence of these receptors has prompted studies on their physiological significance, including attempts at isolating an endogenous ligand. The isolation of a number of substances from bovine brain that competitively inhibit (3H)-diazepam binding to synaptosomal membrane suggests the presence of an endogenous ligand. Two of these substances have been identified as the purines inosine and hypoxanthine. Pharmacological studies of these purines suggest that they may have diazepam-like effect in vivo. The possibility that the brain may contain its own benzodiazepine-like compound is currently being studied.


Some properties of brain specific benzodiazepine receptors: new evidence for multiple receptors. Several new lines of evidence suggest the existence of two or more distinct types of benzodiazepine receptors, in contrast to earlier results suggesting the presence of only one class of receptors. Appropriate thermoinactivation experiments indicate two receptors with different thermostabilities. Several triazolopyridazines, with some of the pharmacological properties of anxiolytics have recently been shown to displace 3H-diazepam and 3H-flunitrazepam with Ki values in the 6 to 100 nanomolar range. These new substances are active in conflict tests in rats and monkeys and prevent metrazol induced seizures in vivo, but strikingly lack the ataxia and sedative properties of the benzodiazepines. Hill analyses of dose-response curves for some of these substances yields Hill coefficients in the range of 0.4--0.6, suggesting that these compounds may be able to discriminate between several types of benzodiazepine receptors.


Benzodiazepine receptors: cellular and behavioral characteristics. Brain specific benzodiazepine receptors appear to mediate the pharmacological properties of benzodiazepines. A neuronal localization for these receptors is suggested by the parallel decrease in the number of benzodiazepine receptors and cerebellar Purkinje cells in "nervous" mutant mice. Electrophysiological results are compatible with an action of benzodiazepines on neuronally localized, physiological receptors. Biochemical, electrophysiological and behavioral experiments highlight the possible importance of frontal cortex in mediating the anxiolytic properties of the benzodiazepines. Triazolenetetrazoles act upon benzodiazepine receptors, increase punished responding and protect against penetylenetetrazole-induced convulsions, but do not produce the side effects associated with benzodiazepines or affect classical neurotransmitter systems. The structural similarities between triazolopyridazines, purines and the indole portion of certain peptides may provide insights into the nature of the endogenous ligand.


A test of anxiety that distinguishes between the actions of benzodiazepines and those of other minor tranquilisers and of stimulants. The effects of minor tranquilisers and of stimulant drugs were studied in the Social Interaction test of anxiety in which the illuminance and unfamiliarity of the test arena are manipulated. Acute administration of sodium phenobarbitone (25 mg/kg) was without effect. Acute administration of sodium phenobarbitone (35 mg/kg) and of meprobamate (60 mg/kg) produced sedation: both locomotor activity and social interaction were reduced. On the other hand, amphetamine sulphate (2 mg/kg) and caffeine citrate (20 mg/kg) reduced social interaction, but increased locomotor activity. Chronic administration dissociated the pattern of results produced by sodium phenobarbitone (35 mg/kg) from that produced by flurazepam (0.5 mg/kg). With chronic treatment (5 days) neither drug reduced motor activity, but whereas phenobarbitone increased social interaction regardless of the test illuminance and unfamiliarity, the increase produced by flurazepam was limited to the more stressful test conditions, i.e., when the arena was unfamiliar or brightly lit.


A synthetic non-benzodiazepine ligand for benzodiazepine receptors: a probe for investigating neuronal substrates of anxiety. CL 218,872 is the first non-benzodiazepine to selectively displace brain specific 3H-diazepam binding with a potency comparable to that of the benzodiazepines. Like the benzodiazepines, CL 218,872 increased punished responding in a conflict situation and protected against the convulsions induced by pentylenetetrazole. These three pharmacological properties are highly predictive of anxiolytic activity. Unlike the benzodiazepines, however, CL 218,872 was relatively inactive in tests designed to measure effects on neuronal systems which utilize GABA, glycine and serotonin as transmitters. Furthmore, CL 218,872 was relatively free of the ataxic and depressant side effects commonly associated with the benzodiazepines. Because of this high degree of selectivity, CL 218,872 may represent a new probe for investigating neuronal substrates of anxiety.


Antagonism by some beta-adrenoceptor-blocking agents to cholinergic stimulation of skeletal muscle in vitro. Antiacetylcholine activity some beta-adrenoceptor-blocking drugs was investigated using isolated guinea pig cremaster muscle and frog fectus abdominis muscle. On the cremaster muscle, the antagonism to acetylcholine was non competitive in K0 1313, (+/-)-INPEA and (--)-INPEA, competitive in (+)-INPEA and functional in practolol; All three INPEA isomers, practolol and propranolol behaved as noncompetitive antagonists of acetylcholine on frog rectus muscle. Caffeine-induced contractions of this muscle were partially inhibited by propranolol but not by the other drugs. It is suggested that the beta-adrenoceptor-blocking drugs produce their antiacetylcholine action by interaction with sites on the muscle which are different from the cholinceptor, and which vary between compounds and species.


The assessment of sublethal effects of pollutants in the sea. Review of the problems. Sublethal effects of pollution may be significant to survival of a stock of marine fish or even a species. Such effects sometimes lead to reproductive failure and have been identified so far only in freshwater systems. Atlantic salmon have disappeared from many streams in Europe and eastern North America, partly as a result of pollution in their freshwater spawning areas and in their estuarine nursing grounds. Reductions in populations of marine fishes due to pollution solely have not yet been demonstrated. However, Baltic Sea seals, where reproductive failure is apparently associated with high concentrations of DDT and polychlorinated biphenyl in the blubber, may have suffered a decline owing to the presence of these organochlorines. Sublethal effects of pollutants have been studied in the laboratory, essentially under four categories: (1) physiology (growth, swimming performance, respiration, circulation); (2) biochemistry/cell structure (blood chemistry, enzyme activity, endocrinology, histochemistry); (3) behaviour/neurophysiology; and (4) reproduction. Not all pollutants elicit meaningful responses in all categories, and a response is not always linear with pollutant concentration. For application to survival of populations the response has to be ultimately related to a healthy progression through a full life cycle, including successful reproduction. In recent time, physiological studies have moved into polluted marine environments with mobile laboratories having continuous sampling capability, to observe effects of pollutants in situ on marine organisms. The Controlled Ecosystem Pollution Experiment (Cepex) in Saanich Inlet, British Columbia, endeavours to investigate the effects of low concentrations of pollutants on marine organisms in large plastic silos having a slow replacement of water.


The need for sublethal studies.

The need for sublethal studies. In problems of waste management, the preoccupation of the would-be manager is the means whereby waste may be released to the environment without impairing the health of the biota inhabiting the receiving waters. In such a situation, measurements based upon acute poisoning are unhelpful since they tell nothing of the impact that the much lower concentrations found at some distance from the waste source have upon the ability of the affected organisms to undertake the responses necessary to ensure survival and more particularly to reproduce successfully. Such responses can only be investigated with organisms not at the point of death, i.e. in truly sublethal studies.


Physico-chemical limitations in experimental investigations. An element or compound in a natural water system is usually distributed between a variety of physico-chemical forms, both dissolved and particulate. The distribution is determined by the properties of the ion or molecule in question and by a number of major variables, including ionic strength, the nature and concentrations of major dissolved elements, particulate matter and organic complexing material, pH and the electron activity (pE); it may thus vary widely between different environments. The design of experiments to study sublethal effects of pollutants in sea water ideally requires that the test medium is closely matched to the environment for which information is needed, with respect to the ranges of concentration and activity, and the chemical speciation, of the pollutant and of any other constituents which may influence its effects. This in turn requires either that the pollutant can be added in the appropriate forms, implying a knowledge of the existing speciation, or that the added material rapidly exchanges with the forms already present. The implications of these requirements are most apparent for those pollutants that show complex chemical behaviour in sea water. This account concentrates on metals of toxicological significance. Consideration of particulate associations, redox speciation, and complex formation in the dissolved state with inorganic and organic ligands, suggests that physicochemical factors limit the usefulness, in terms of environmental predictions, of experimental studies of biological effects of metals, both inherently and through inadequate knowledge of environmental speciation and the mechanisms and rates of interconversion between species. Of particular importance are non-equilibrium features in speciation, such as the presence of thermodynamically unstable oxidation states and of kinetically non-labile associations. Interpretation of the nature of these associations is complicated by the presence of colloidal and organic macromolecular material in dissolved fractions as conventionally defined. While the chemical behaviour of some substances in sea water is considerably less complicated than that of the trace metals, there is a need with all types of pollutants for greater attention to physico-chemical factors in both the design and interpretation of experiments to investigate biological effects.


Biological variables, especially skeletal deformities in fish, for monitoring marine pollution. When considering principles for selection of indicators, i.e. biological variables, for monitoring marine pollution, it must be regarded as important to search for effects on the highest possible level of organization. For a global monitoring programme there are, however, many practical limitations in the number of useful indicators. The paper suggests skeletal deformities in fish as one possible indicator for this purpose in the future and gives a review on the occurrence, effects, causative factors and possible mechanisms of skeletal deformities in fish.


An experimental approach to the determinants of biological water quality. A case is presented for the use of experimental bioassay techniques to detect and measure variations in water quality in the marine environment by exposing suitable organisms in the laboratory to water samples collected in the field. A technique is described which was developed for this purpose with the use of a clonal hydroid; preliminary results from Swansea Bay show that it is sensitive to the variations in water quality that occur there. Chemical techniques are being developed for use in conjunction with such bioassays to identify the kinds of contaminants responsible for a detected effect, and some preliminary experiments suggest that divalent metals and the volatile constituents of hydrocarbons can be removed selectively from sea water.


Bioaccumulation of marine pollutants.

Bioaccumulation of marine pollutants. Bioaccumulation of pollutants can occur from sea water, from suspended particles, from sediments and through food chains. The rate at which accumulation occurs in an organism depends not only on the availability of the pollutant but also on a whole range of biological, chemical and environmental factors. The ultimate level which is reached is governed by the ability of the organism to excrete the pollutant or, alternatively, store it. This latter course often leads to the attainment of very high concentrations and sometimes no equilibrium level is ever reached. Two particular topics which are considered are the biological amplification of pollutants along food chains and the development of tolerance which sometimes occurs.


Behavioural responses of marine poikilotherms to pollutants. Selected behavioural responses of marine fishes and invertebrates which are reportedly capable of disruption or impairment by petroleum, heavy metals, pesticides and other pollutants are listed. The usefulness of these and other performance functions to regulatory agencies charged with formulation of saline water quality criteria appears somewhat limited. At present, however, motor funcitons such as swimming performance, locomotion, and equilibrium, as well as physiological responses, especially respiratory patterns, may have some potential for biomonitoring of wastes discharged into coastal environments.


Experiments with large enclosed ecosystems. Three of the major advantages of enclosure experiments are that they ensure (1) that the same populations are sampled over a long period; (2) that populations of at least three trophic levels are initially enclosed in naturally occurring proportions and that they are self sustaining over a long experimental period; and (3) that replicate enclosed populations can be experimentally manipulated. There are two disadvantages which must be mentioned. These are (1) that vertical mixing, which may be reduced by as much as an order of magnitude compared to the open sea, will undoubtedly affect the sinking rates of phytoplankton and may influence the structure of the population; and (2) that as a general rule the larger and therefore more expensive the enclosures become, the more difficult it is to run sufficient replicates. An experiment is described in which 1 microgram Hg/l was added to two 95 m3 bags (3 mdiameter by 17 m deep) and the response of the pelagic population monitored over the following 20 days. A further 10 micrograms Hg/l was then added to each enclosure and the response measured for a further 20 days. The results indicated that: (i) inorganic mercury added to the water column is very rapidly transformed into 'bound' or 'non-reactive' mercury and that about 25% of the mercury added was recovered associated with the organic material settling to the bottom of the bags; (ii) the response of the biological population to 1 microgram Hg/l was very limited and in fact a transient reduction in photosynthetic carbon uptake per unit chlorophyll was the only noticeable effect and there were no changes in population size or structure that could be attributed to mercury; (iii) at 10 micrograms Hg/l the zooplankton population was reduced markedly and this did produce changes in the structure of both the zooplankton and phytoplankton populations. These results are similar to the results of a comparable experiment carried out in Vancouver Island (Cepex) and point to the conclusion that the levels of mercury found in surface waters around the coast of the U.K. (0.001--0.022 microgram Hg/l) are one or two orders of magnitude below the levels at which a response of the biological population can be demonstrated. The usefulness of large scale enclosed ecosystems for further pollution research is discussed and it is concluded that those facilities that provided a link between the water column and the sediments would be most useful since they would (1) enable estimates to be made of the flux rates of pollutants from the water column to the sediments; and (2) allow experiments to be carried out with the pollutant in contact with sediment in its natural form.


Pollution-induced changes in populations. The effects of pollution by organic matter, oil or industrial waste on marine communities are remarkably similar. Diversity values fall, biomass and numbers of organisms initially rise and then fall as the pollution load is increased. Diversity indices are, however, insensitive to pollution-induced changes and have to be assessed subjectively. Departure from a log-normal distribution of individuals among species offers a sensitive and objective method of assessing perturbation effects on communities. Under severe pollution stress, the dominant species are those which have a flexible life-history ranging from direct development to a planktonic larva and the ability to undergo short-term genetic selection. Species have a somewhat less flexible life-history strategy show increased abundance under conditions of slight pollution. The increase in abundance of seven or eight neither rare nor common species, which gives the departure from a log-normal distribution, is suggested as being the most significant and the earliest detectable change caused by pollution in a community. Thus the presence of a species in a polluted area may be more a question of life-history strategy than the tolerance of adverse environmental conditions. If this hypothesis is correct, considerable doubt must beplaced on the ecological relevance of data from toxicity tests.


Measurement of the responses of individuals to environmental stress and pollution: studies with bivalve molluscs. Certain physiological differences between individuals in different populations of the mussel, Mytilus edulis, are described. In particular, the scope for growth differs in space and time and may be used to assess the animals' physiological condition. When the required measurements are made in the field, the rates of growth predicted from the physiological data agree well with observed rates of growth. An alternative approach utilizes mussels transplanted to various waters, with indices of condition then measured in then measured in the laboratory under standard conditions; an example of this approach is illustrated. Laboratory experiments are used to equate various levels of physiological condition with fecundity, in an attempt to equate physiological effects on the individual with likely population damage. A cytochemical index of stress is described, based on the latency of lysosomal enzymes; spatial variability in this index, and its relation with the scope for growth, are discussed. Finally, the results of some experiments on the effects of petroleum hydrocarbons on mussels are described and the presence of inducible activity of NADPH-dependent tetrazolium reductase in the blood cells is demonstrated. Certain considerations that apply in adopting similar measurements of biological effects of pollution in environmental monitoring programmes are discussed.


The uses of experimental ecosystems.

The uses of experimental ecosystems. The experiments conducted so far with large experimental ecosystems have probably taught us more about the general ecological interactions in such systems than about subtle long-term effects of pollutants. This knowledge is not only valuable in its own right but may be more useful in an indirect rather than a direct way, in understanding the robustness of these systems and so evaluating the general effects of stresses.


The monitoring of biological effects: the separation of natural changes from those induced by pollution. An added mortality rate of eggs, larvae and juveniles of fish populations, or impact, is assumed to be density independent. The total mortality from hatching to recruitment is represented by the fecundity, and any increment in density independent mortality implies a decrement in density dependent mortality. At high stock the condequence is an increase in stock towards a position of less resilience: at low stock less resilience is found with a decrease in stock. In general impact generates a shift of K-strategy, the self-stabilizing strategy, to r-strategy, and opportunistic one. In a fish population very little impact should be tolerated at low stock because it would prevent recovery to a management objective such as maximum sustainable yield. At high stock, impact may generate more stock at an unknown risk.


Standards and environmental criteria: the practical application of the results of laboratory experiments and field trials to pollution control. The derivation of standards and their application to the regulation of marine environmental quality are discussed, including the rôle of monitoring. The significance of experimentally determined sublethal effects in relation to the setting of environmental standards is considered. Contemporary approaches to pollution control are compared especially as they affect problems of standard setting.


Development of spontaneous motility in chick embryos. Effects of drugs acting on monoaminergic synaptic receptors. The development of the effect of agonists of monoaminergic transmitters--LSD (20 and 200 micrograms/kg egg weight), apomorphine (1 and 3 mg/kg e.w.) and clonidine (2.5 mg/kg e.w.)--was studied on 11- to 19-day chick embryos. All three substances already significantly depressed spontaneous motility in 11 and 13-day-old embryos and their depressant effect increased as embryogenesis progressed. In chronically decapitated embryos (Sedlácek and Doskocil 1978) they had practically the same depressant effect as in normal embryos, showing that their activity is not bound unconditionally to supraspinal compartments of the CNS. These results are further evidence of the participation of central monoaminergic systems in embryonal motility. The finding that the three test drugs take effect during embryogenesis before sensitivity to monoaminergic transmitters appears remains unexplained.


Psychiatry and endocrinology: an expanding interface. There is growing documentation that a variety of hormones can both influence mood and behavior and be affected by them. Endocrine measures thus provide us with a readily accessible source of information about how the brain mediates between stimuli arising from the external social environment, intrapsychic phenomena, and the body's internal physiological needs. This paper will review recent psychoendocrine research which has in particular suggested several new concepts: (1) the brain itself might be viewed as a "target organ" for certain hormones; (2) specific hormonal correlates of certain clinical psychiatric syndromes, such as anorexia nervosa and depressive illness, might serve as biological markers which could help in the differential diagnosis of these conditions; and (3) peripheral hormonal determinations, by virtue of the role played by central nervous system (CNS) neurotransmitters in endocrine regulation, may provide important specific information about possible CNS biogenic amine abnormalities associated with the pathogenesis of certain psychiatric disorders.


Acute and chronic effects of three benzodiazepines in the social interaction anxiety test in mice. The effects on active social interaction of acute and chronic dosage with diazepam (1 mg/kg), desmethyldiazepam (2 mg/kg), and chlor-desmethyl-diazepam (0.125 mg/kg) were studied in pairs of mice. The mice were tested under either high or low levels of illumination. In all cases acute drug treatment significantly reduced social interaction, but this was not seen with chronic treatment (9 days). Two of the drugs, diazepam and desmethyldiazepam, showed an anxiolytic action, i.e., these drugs resulted in significantly less variation in social interaction with the change in light levels, compared with vehicle-injected controls.


Non-enzymic interactions of nicotinamide adenine dinucleotide, of some of its synthetic analogues and other compounds with orthophosphate. Changes in the ultraviolet (UV) absorption spectra of nicotinamide adenine dinucleotide (NAD), of its synthetic analogues, and of adenosine and its derivatives in the presence of high concentrations of orthophosphate were studied. The role of the carboxamide group of the nicotinamide moiety of NAD on these spectral changes was investigated by replacing that group with an acetyl or aldehyde group. The effect of the 6-amino group of the purine was investigated by studying the interaction of deamino-NAD and various adenosine derivatives with orthophosphate. 2,4-Dinitrophenol was also found to give a charge transfer complex with phosphate. Molar extinction coefficients (E) and association constants (K) of these charge transfer reactions were determined.


[Digital computer analysis of the electromyogram: preliminary report (author's transl)]. This is a preliminary report of a method of digital computer analysis of the electromyogram recorded from twenty sites in biceps brachial during fixed voluntary effort. The method allows several EMG parameters to be studied. The results in a group of normal subjects have been compared with those in patients with neuromuscular disease. Three parameters have proved of value in differentiating normal subjects from those with neurogenic disease.


12-Hour simultaneous registration of acid reflex and peristaltic activity in the oesophagus. A study in normal subjects. Twelve-hour simultaneous registration of acid gastro-oesophageal reflux and peristaltic activity in the oesophagus was carried out on 30 healthy subjects. The intensity of the acid gastro-oesophageal reflux was determined by automatic integration of the pH variation. Acid gastro-oesophageal reflux to pH less than or equal to 4 occurs in normal subjects within a range of 0--2.4% of the total registration period. The intravariation was measured in 10 investigations on 1 subject, and lay within the intervariation. To maintain the pressure-measuring system intact, 3 ml H2O/h were fed to the proximal and distal pressure catheters, respectively; it has been shown that this small quantity of water has no influence on the pH variation. Peristaltic activity for the entire measuring period was recorded and related to the individual reflex episodes. The total activity was found to be dependent on the level of consciousness, with little activity occurring during sleep. A positive correlation was found between the lowest pH during a reflux episode and the peristaltic activity in the oesophagus (p less than 0.001), between the lowest pH during a reflux episode and the duration of the reflux episode (p less than 0.001), and between the peristaltic activity and the duration of the reflux episode (p less than 0.001). During long-term registration of oesophageal pH it appears that pH less than or equal to 4 is a usable parameter for distinguishing between pathological and non-pathological acid gastro-oesophageal reflux. Sudden falls in pH to below 4 release increased peristalsis in the oesophagus.


The osmotic fragility of red blood cells: a re-evaluation of technical conditions. The osmotic fragility of red blood cells is influenced by even modest environmental changes. Consequently, the technical procedure must be strictly standardized. This implies that temperature equilibrium of the buffered salt solutions should be reached prior to the addition of blood. Furthermore, since erroneous statements concerning the composition of phosphate buffers regularly used to secure correct pH of the salt solutions have repeatedly appeared in the literature, pH control of such solutions prior to use becomes essential.


[Position of behavior therapy among the psychiatric therapies]. In the fourth table, we have classified the most important measures of behaviour therapy: desensitivization, operating conditioning, aversive therapy and negative learning. These courses of action can play an important role in psychiatry and can enrich the therapeutic repertory through their rational use, placed in a general plan of treatment. Moreover, these methods are usually excluded from the tought theories and they do not see in the neurotic troubles a consequence of unconscious conflicts; these conflicts must become conscious again, but they must appear, then, as the result of the learning of bad behaviour.


Prednisone effect on microvascular permeability in patients with inflammatory rheumatic diseases. The transcapillary escape rate of albumin was measured in 27 consecutive patients with inflammatory rheumatic diseases before and after 1 and 7 days of prednisone treatment in doses of 45 mg/day. The transcapillary escape rate decreased from 7.33%/h (range 5.11-9.55) before prednisone treatment to 3.11%/h (0.04-6.18) (p less than 0.05) after 1 day of treatment and 5.80%/h (4.36-7.24) after 7 days of treatment. It is concluded that prednisone inhibits vascular permeability in patients with inflammatory rheumatic diseases.


Antennal hair erection in male mosquitoes: a new mechanical effector in insects. Male Anopheles mosquitoes erect their antennal hairs prior to mating. The erectile mechanism resides in a unique annulus at the base of each hair whorl. It appears that the insect regulates the degree of hydration of this annulus. When the annulus is made to swell the attached hairs are pushed to their erect position.


Infantile polyarteritis nodosa. A case report. The clinical and postmortem findings in a 4-month-old infant with polyarteritis nodosa are presented. The relationship of this condition to mucocutaneous lymph node syndrome (MLNS) is discussed, and the relevant literature is reviewed.


Effects of pH, Ca2+, temperature, and protease pretreatment on interkingdom fusion. The incubation of carrot protoplasts and cultured Xenopus cells in a protease solution has been shown to enhance their subsequent interkingdom fusion by a high pH/high Ca2+ method. The effects of Ca2+ concentration, pH, and temperature on the frequency of heterokaryon formation have also been studied. Potentially viable heterokaryons have been repeatedly produced at high frequencies (consistently greater than 10%), far exceeding those so far achieved in PEG-mediated fusion. Cell aggregates are readily dispersed after this method of fusion, permitting the accurate estimation of fusion frequencies.


Significance of antral pH for gastrin release by insulin hypoglycemia in duodenal ulcer patients. The significance of antral pH for the basal serum level of immunoreactive gastrin and for the release of gastrin during insulin hypoglycemia has been studied in duodenal ulcer (DU) patients. To permit paired comparisons, 14 DU patients underwent two or three tests with insulin. Venous blood samples were collected at fixed intervals for determination of gastrin (radioimmunoassay). In the first insulin test, the gastric juice was aspirated; in the second test, the stomach was perfused with citrate-phosphate buffer, pH 7.0; and in the third test the stomach was perfused with 0.1M HCl, pH 1.0. The rate of buffer or acid perfusion was adjusted, and the pH of the perfusate was kept above 5.0 and below 1.3, respectively. Gastric perfusion with buffer or acid for 1 hour did not affect the basal serum gastrin level, nor did perfusion with buffer for 3 hours. Insulin hypoglycemia stimulated acid secretion and produced a significant integrated serum gastrin response during gastric aspiration, but the gastrin response was four times greater during buffer perfusion. Acid perfusion abolished the gastrin response. From our previous and present findings, it is concluded that the gastrin in serum during basal conditions is of extra-antral origin and is independent of antral pH. Insulin hypoglycemia releases antral gastrin by a pH-sensitive mechanism in DU patients; the release is suppressed at pH 1.3 or less and also is markedly inhibited when the gastric juice is aspirated.


[Sigmoid perforation during the course of cholesterol emboli simulating polyarteritis nodosa (author's transl)]. Cholesterol emboli have only recently been recognized as a pathological entity and their clinical picture is still not clearly defined. A case is reported of a patient presenting signs of a severe systemic affection with distal arteriolitis and also general and biological signs of a severe inflammatory process having the particular characteristic of apparent corticoid sensitivity. The patient died following ischemic necrosis of the sigmoid from perforation and peritonitis, also related to the presence of cholesterol emboli.


[Relationship between the presence of meconium in newborn lambs and postnatal pH and blood gas tension levels (author's transl)]. The pH of the blood and blood gas tension (PO2 and PCO2) were estimated in thirty-two lambs. Blood was taken from the umbilical vein during labour and blood was collected from the left ventricle after birth (1, 10 and 60 minutes). The findings in twenty-one lambds were used to determine the relationship between the presence of meconium on the fleece and the postnatal changes in pH and blood gas tension. pH, blood gas tension and vitality were found to be identical both in the meconium-stained and in the unstained lambs. Within this experiment, there was no relationship between the length of parturition and pH and blood gas tension levels. The pH, PO2 and PCO2 as determined in the umbilical blood showed that the lambs (both meconium-stained and unstained) continue to be in good condition throughout a normal parturition. Postnatal adjustment is rapid and, following normal ventilation, pH, PO2 and PCO2 respectively attain levels of 7.379; 54.7 and 43.7 within sixty minutes. Diminished vitality, resulting from pathological factors, was observed in four lambs.


Age-dependent variations of lysosomal enzymes in human liver. The specific activities, the Km values, and the elution patterns on DEAE 52 and Sephadex G-150 columns of six lysosomal enzymes in human liver during development were studied. The levels of total beta-D-glucuronidase and N-acetyl-beta-D-glucosaminidase activities in childhood liver were higher than those in fetal liver. The Km values of beta-D-glucuronidase and beta-D-galactosidase in fetal liver were about ten times higher than those in childhood liver. The elution patterns on DEAE 52 of beta-D-glucuronidase and on Sephadex G-150 of alpha-D- and beta-D-galactosidases changed with aging. It is suggested that lysosomal enzymes related to degradation of gangliosides and glycosaminoglycans change during development.


Some characteristics of 17 beta-estradiol dehydrogenase from bovine placenta. The activity of 17 beta-estradiol dehydrogenase (E.C. 1.1.1.62) was measured, and its distribution in the subcellular fractions of bovine placenta was compared. Assay of activity was based on the formation of radioactive estrone from 17 beta[4(-14)C]-estradiol. Either NAD+ or NADP+ can serve as cofactor for the enzyme. The nuclear and microsomal fractions of the placental homogenate exhibited the highest specific enzymatic activities before and after treatment with Triton X-100. Electron micrographs of these two fractions prior to treatment with Triton X-100 showed satisfactory purity. 17 beta-estradiol dehydrogenase from bovine placenta exhibits a pH optimum of about 9.5-10.5, and is activated by 5 x 10(-6)M ZnCl2; comparable concentrations of CaCl2 and MgCl2 inactivate the enzyme. The apparent Michaelis constants, Km, for 17 beta-estradiol and NAD+ are 1.4 x 10(-6)M and 5.5 x 10(-5)M respectively. No 17 alpha-estradiol dehydrogenase activity was demonstrable when using 17 alpha-estradiol as substrate.


Marine sterols. VIII. Isolation and structure of sarcosterol, a new sterol with a delta17(20)-double bond from the soft coral Sarcophyton glaucum. The sterol mixture of the southern Japan's soft coral, Sarcophyton glaucum, was found to contain 11 sterols including a novel sterol, 23,24 xi-dimethylcholesta-5,22-dien-3 beta-ol and a new diunsaturated C29 sterol. 22,23-Dihydrobrassicasterol and gorgosterol were the major components in free- and esterified sterols respectively. Brassicasterol was found in S. glaucum, in contrast to the ubiquity of 24-epibrassicasterol in the marine invertebrates in the northern districts. The new sterol (sarcosterol) was isolated; its structure as 23 xi, 24 xi-dimethylcholesta-5, 17(20)-trans-dien-3 beta-ol was based on spectra evidence and comparison with cholesta-5, 17(20)-trans-dien-3 beta-ol.


Urine gamma-glutamyl transferase in rat kidney toxicology: nephropathy by repeated injections of mercuric chloride. Effects of sodium selenite. Groups of 5 male and 4 female Cobs CD rats weighing 250--350 g were injected intraperitoneally, daily for 15 days, with 5 mumol HgCl2/kg, 5 mumol Na2SeO3/kg, or (5 mumol HgCl2 + 5 mumol Na2SeO3)/kg in a 10 ml/kg vol. of saline. Control animals were injected with saline only. Injection of saline or sodium selenite produced neither modification of diuresis, nor of urine elimination of sodium, potassium, chloride, phosphates, urea, creatinine and gamma-glutamyl transferase (GGT). Injection of mercuric chloride induced a massive increase of urine GGT, diuresis and phosphaturia and a decrease of kaliuria and natriuria. Those effects reflect a kidney tubular lesion which seems to be more severe in males than in females. Injection of mixed sodium selenite and mercuric chloride or separate injection of both compounds had similar effects. In both sexes, urine GGT elimination was delayed and about 2 times lower than with HgCl2 alone. In females, the other urine parameters were almost normal whereas in males, diuresis and phosphaturia were slightly increased and kaliuria decreased. The observation of urine GGT elimination attests, in vivo, that sodium selenite decreases tubular toxicity of mercuric chloride and resulting kidney function disturbances.


Marine sterols. IX. Occurrence of 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate in the soft coral, Sarcophyton glaucum. The southern Japan's soft coral, Sarcophyton glaucum, was found to contain several polyhydroxylates steroids. One of the minor components was isolated and its structure was established as 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate from spectral evidence and from comparison with a reference compound, 5 alpha-spirostan-1 beta, 3 beta, 5 alpha, 6 beta-tetrol, which was synthesized from ruscogenin. A mixture of 1 beta, 3 beta, 5 alpha, 6 beta-tetra hydroxy C27- and C28-sterols was also isolated.


Preferential homing of passively transferred T cells into skin allografts of mice. An assay which uses two differentially labeled cell populations was used to characterize the preferential localization of passively transferred syngeneic cells immunized to specific alloantigens. Splenocytes cytotoxic to B10.D2 and B10.BR alloantigens were harvested from (C57BL/6 X A/J)F1 (B6AF1) donors bearing acutely rejected skin allografts. One population was labeled in vitro with 3H-thymidine and the other with 14C-thymidine. The labeled cells were pooled and then transferred i.v. into B6AF1 hosts bearing 5-day-old skin grafts from B10.D2 and B10.BR donors. After 48 hr the mice were killed, and the relative amount of cells present in the skin grafts and draining axillary lymph nodes was derived by comparing the 3H:14C ratios of the harvested tissues. The results of these studies indicated that cytotoxic splenocytes harvested from donors bearing acutely rejected skin allografts preferentially localize to the relevant skin allograft after passive systemic transfer. The homing behavior of these splenocytes was augmented by T cell enrichment and significantly diminished by pretreatment with anti-Thy-1.2 serum plus rabbit complement. There was no evidence of preferential homing within the draining axillary lymph nodes. It can be concluded that a T cell population derived from in vivo sensitized splenocytes exhibits preferential homing to relevant skin allografts upon passive transfer.


Renal excretion of hydrogen ions in stone formers. Urinary hydrogen ion excretion has been studied in 68 adult stone formers and in 50 controls. Under basal state, the stone formers showed statistically significant higher urinary pH, and lower 24-hour urinary titrable acid, ammonium and total hydrogen. On the 3rd day of ammonium chloride loading test, the stone formers showed statistically significant higher urinary pH and lower 24-hour urinary titrable acid, ammonium, total hydrogen and plasma bicarbonate. 'Clearance' indices of hydrogen ion excretion were also depressed in a great majority of the stone formers. The results indicate the frequent co-existence of defective urinary acidification with nephrolithiasis.


[The effect of large burns in ruminants on the edibility of meat]. The effect of non-contact burns was studied on a model of a slaughter ruminant. The study included the examination of the penetration of germs into the blood stream and into the meat and of the main changes characterizing the ripening of the obtained meat. The tests were conducted with two groups of animals, killed 1) at the beginning of the development of the infection process in the burn, 2) in a health state in which the prognosis was unfavourable quo ad vitam. It was found on the basis of haemocultivation, microbiological examination of the samples of organs and meat, and examination of pH values in the meat that the natural body barriers were destructed and the biochemistry of the muscular tissue was impaired. The penetration of the germs through the natural barriers of the organism was recorded also before the initiation of the development of the infection in the burn. The acidification of the meat worsened post mortem. It is possible, on the basis of the facts which were revealed, to present the following recommendations for the practical use of the results in the veterinary inspection of meat in ruminants with large burns: to take samples for microbial examination, even though the animal has been slaughtered in the earliest stage of the disease; to determine the pH in the meat obtained from the slaughtered animals and to expect worse acidification and imperfect ripening of the meat.


Polymorphism of the second component of human complement (C2). Observation of the rare phenotype (C2 2 (= C2 B) and data on the localization of the C2 locus in the HLA region. The polymorphism of the second component of human complement was studied by means of isoelectric focusing in polyacrylamide gels with subsequent complement-dependent lysis of sensitized sheep erythrocytes in an agarose overlay containing C2-deficient or normal human serum. In a material of 289 unrelated individuals the following gene frequencies were observed: C21=0.965 and C22=0.035. The rare phenotype C2 2 (=C2 B) could be seen once in a child of a C2 1--2 heterozygous mother. The investigation of the C2/HLA relationship revealed a very close linkage: Among 62 informative meiotic divisions one recombination between HLA-B and C2 was found (i.e. 1.61%); in addition, C2(2) was significantly associated with HLA-B15 and -Cw3. In a family with an HLA-B/D(DR) crossover C2 segregated together with HLA-D(DR). This supports the assumption of a C2 structural locus outside HLA-B, probably near HLA-D(DR).