Biochemical and histofluorescence studies of catecholamines in superior cervical ganglia in organ culture.

The metabolism of catecholamines in rat superior cervical ganglia in organ culture was examined by biochemical and histofluorescence methods. Pronounced increases in both norepinephrine and dopamine content were observed in the cultured ganglia. Norepinephrine levels were more than doubled after 12 hours in culture and reached a maximum after 24 hours. The greatest increase in norepinephrine concentration occurred in the region of the postganglionic nerve trunks and was correlated with an accumulation of intense catecholamine fluorescence in the stumps of the severed postganglionic nerves. Since the rate of norepinephrine synthesis was unaltered, the increase in norepinephrine levels in cultured ganglia appears to be a result of blocked axoplasmic transport of this amine out of the ganglia. The dopamine content of the cultured preparations was not altered after 24 hours but increased rapidly thereafter and attained a maximum at 48 hours. The changes in dopamine did not parallel the changes in norepinephrine either in time course or distribution. The elevated levels of dopamine were accompanied by an increased rate of dopamine synthesis. It is suggested that the increased dopamine content in cultured ganglia is the result of an enhanced synthesis of this amine by specific dopaminergic cells.


Biochemical and functional evaluation of the sympathectomy produced by the administration of guanethidine to newborn rats.

The administration of guanethidine to newborn rats has been shown by morphological criteria to destroy sympathetic neurons. Newborn rats were injected with guanethidine (50-100 mg/kg/day for 20 days). Upon maturation (at 10 weeks old), the degree of destruction of the sympathetic nervous system (sympathectomy) was assessed. Marked decreases (80-98%) in the norepinephrine concentration in several tissues (heart, spleen, intestine, mesentery, kidney, uterus, vas deferens) were observed in the guanethidine-treated rats when compared to saline-treated controls. No changes were observed in the epinephrine concentration in the adrenals or in the norepinephrine levels in whole brain. Analysis of brain areas showed no change in the norepinephrine levels in brain stem and cerebrum and a small (18%) decrease in the cerebellum. Stimulation of the sympathetic vasomotor outflow in the pithed rat preparation produced almost no response in guanethidine-treated animals. Periarterial nerve stimulation of the isolated perfused kidney preparation also produced essentially no response in guanethidine-treated animals. Isolated intestinal preparations from guanethidine-treated animals responded to nerve stimulation with contractions rather than relaxation as seen in preparations from control animals. Isolated vas deferens preparations responded normally to nerve stimulation despite a 95% decrease in tissue norepinephrine concentration. These data indicate that administration of guanethidine to newborn rats produces a more complete peripheral sympathectomy, especially of the vasculature, than immunosympathectomy or neonatal administration of 6-hydroxydopamine and does so with no significant effect on central noradrenergic neurons.


Time course of the effect of reserpine administration on tyrosine hydroxylase activity in adrenal glands and vasa deferentia.

During the first several hours after administration of reserpine, tyrosine hydroxylase activity in rat adrenal slices and in isolated intact vasa deferentia of mice and rats is profoundly reduced, although no effect on enzyme activity in isolated fortified homogenates of these tissues is demonstrable. This effect, observed only in intact preparations, is competitively antagonized by addition to the medium of the synthetic pterin cofactor, 6,7-dimethyltetrahydropterin (DMPH4). Kinetic analysis of the effect of acute reserpine treatment on tyrosine hydroxylase activity in these isolated, intact tissues indicates that the Km for the pterin cofactor is increased but the Vmax is not altered. The results indicate that reserpine produces its inhibition of tyrosine hydroxylase by preventing catecholamine storage and causing elevated levels of free intraneuronal norepinephrine. The catecholamine inhibits the enzyme in a manner which is competitive with the pterin cofactor. After more chronic reserpine treatment, when catecholamine stores are severly depleted, this inhibition of tyrosine hydroxylase activity in intact tissues is no longer apparent. After 3 days of treatment, increased levels of tyrosine hydroxylase are demonstrable in the adrenal glands of rats but not in the vass deferentia of either mice or rats. The increased enzyme levels in the adrenal gland are presumably due to increased enzyme formation.


Stimulation of adenosine 3',5'-monophosphate formation in rat cerebral cortical slices by methoxamine: interaction with an alpha adrenergic receptor.

Methoxamine elicits a rapid accumulation of adenosine 3',5'-monophosphate (cyclic AMP) in rat cerebral cortical slices with maximal effects at 100 muM. The accumulations of cyclic AMP elicited by this amine are completely blocked by the alpha adrenergic antagonists, phenoxybenzamine and dihydroergokryptine, partially blocked by the alpha antagonist, phentolamine, and unaffected by the beta blocking agent, propranolol, or by the local anesthetic, tetracaine. The magnitude of the accumulations of cyclic AMP elicited by methoxamine in cerebral cortical slices of four rat strains (F-344, ACI, BUF, and Sprague-Dawley) exhibit a strong negative correlation with spontaneous motor activity and a positive correlation with the magnitude of norepinephrine-elicited accumulations of cyclic AMP. The stimulatory interaction of methoxamine with alpha adrenergically regulated cyclic AMP-generating systems differs from the interaction of norepinephrine with alpha receptors as evidenced by the following observations: 1) the stimulatory effects of methoxamine and norepinephrine are nearly additive; 2) the stimulatory effects of methoxamine and adenosine are nearly additive, whereas the effects of norepinephrine and adenosine are much more than additive. Methoxamine, however, does not increase further the magnitude of accumulation of cyclic AMP elicited by a combination of norepinephrine and adenosine. The results are consonant with the interaction of methoxamine with alpha adrenergic receptors which are normally activated by norepinephrine only to a marginal extent. However, in the presence of adenosine, these receptors are now sensitive to activation by norepinephrine.


Effect of the H2-receptor antagonists (burimamide and metiamide) on gastric secretion stimulated by histamine and its methyl derivatives.

This study was done to determine the comparative effectiveness of burimamide and metiamide as antagonists of gastric secretion stimulated by histamine and its methyl derivatives, Nalpha-methylhistamine, N-alpha,N-alpha-dimethylhistamine and 4-methylhistamine, in dogs with vagally denervated (Heidenhain pouches) and vagally innervated gastric mucosal septal pouches (Pavlov-type pouches). The secretagogues were always given by continuous i.v. infusion to produce steady states of secretory activity in the fasted conscious dogs; the antagonists were given by either rapid "bolus" i.v. injection or continuous i.v. infusion. With bolus injections, both antagonists promptly inhibited the secretion produced by histamine and its methyl derivatives. When control secretory rates were similar, 40 mumol of burimamide per kg and 4 mumol of metiamide per kg produced the same degree of inhibition. When the antagonists were also given by continuous i.v. infusion, the difference between them was greater, metiamide being 15 to 17 times more potent than burimamide. The effectiveness of the antagonists was not changed by vagal denervation. Symptoms of toxicity to burimamide developed at doses in excess of 30 mumol/kg/hr; none occurred with doses of metiamide ranging from 1.8 to 7.5 mumol/kg/hr.


4-Nitrocatechol production from rho-nitrophenol by rat liver.

Time course studies of rho-nitroanisole O-demethylation revealed formaldehyde production in excess of rho-nitrophenol (PNP) and 4-nitrocatechol (NTC) formation by rat liver microsomes. This indicated that these products (PNP, NTC) were metabolised further. The hydroxylation reaction PNP yields NTC showed substrate and product inhibition and a requirement for reduced nicotinamide adenine dinucleotide phosphate and O2 and was localized in liver microsomes. It was strongly activated by ascorbic acid, cysteine, adenosine triphosphate or hydroxylamine in vitro and enhanced by phenobarbital treatment in vivo. Mercapturic derivatives were metabolized to the corresponding hydroxy compounds with the same speed as their parent compounds. Both PNP and NTC were metabolized to the corresponding glucuronide and sulfate conjugates. On the other hand, the PNP or NTC glucuronides and sulfates were metabolized with liver microsomes to PNP and NTC.


Rate-dependent Effects of drugs. II. effects of some major tranquilizers on multiple fixed-ratio, fixed-interval schedule performance.

The effects of promazine, chlorpromazine, triflupromazine, prochlorperazine, trifluoperazine, perphenazine, fluphenazine, haloperidol, benzquinamide, tetrabenazine and chlorprothixene were determined on the rate of conditioned key pecking of pigeons under a multiple fixed-ratio 30, fixed-interval 5-minute schedule of food presentation. Chlorpromazine, prochlorperazine, perphenazine, chlorprothixene and tetrabenazine decreased responding relatively more within the fixed-interval component than within the fixed-ratio component and also produced rate-dependent effects within the fixed interval component, increasing the low rates of responding early in the fixed-interval but decreasing the high rates of responding in the terminal parts of the fixed interval. Triflupromazine, trifluoperazine, fluphenazine and haloperidol also decreased responding relatively more within the fixed-interval component than within the fixed-ratio component, but did not produce rate-dependent effects within the fixed-interval component. Both low and high rates of responding within the fixed interval were decreased only by these four drugs and they produced small and inconsistent decreases in the quarter-life values. Promazine and benzquinamide decreased responding relatively more within the fixed-ratio component than within the fixed-interval component and also produced rate-dependent effects within the fixed-interval component. There was a structure-activity relationship between the chemical group on the benzene ring of the phenothiazine nucleus and the rate-dependent effect on responding within the fixed-interval component. Phenothiazines with a hydrogen or chlorine group on the benzene ring produced a rate-dependent effect on responding within the fixed interval, while phenothiazines with a trifluoromethyl group on the benzene ring did not produce a rate-dependent effect on responding within the fixed interval.


Acidification in the rat proximal jejunum.

1. Production of hydrogen ions by the rat proximal jejunum was investigated using the everted sac technique. 2. Acidification occurred in the absence of glucose, increasing on addition of glucose to reach a maximal value. An apparent Km of 1-78 mM was derived for the glucose-dependent process. 3. Acidification in the presence of glucose was inhibited by 10 mM-2:4-dinitrophenol, 10 mM phlorrhizin, 10 mM aminophylline and anaerobiosis. 4. Histamine, ethylenediamine tetraacetic acid (EDTA), ouabain and acetazolamide, compounds known to alter acid production in gastric mucosa had no effect on jejunal acidification. 5. Galactose and 3-O-methylglucose failed to increase acidification; in contrast, mannose and fructose did lead to increases, indicating metabolic origin of the hydrogen ions. 6. Serosal and mucosal lactate production were measured and the calculated percentage of hydrogen ions possibly derived from this source was shown to account for only a small proportion of acidification. 7. The greatest increase in acidification with minimal simultaneous production of lactate occurred with ATP which was shown not to enter intestinal tissues. 8. A hypothesis for acidification, that of the break-down at the mucosal surface of ATP from intracellular metabolic sources, is proposed and its relevance to the postulated microclimate is discussed.


Effects of potassium, veratridine, and scorpion venom on calcium accumulation and transmitter release by nerve terminals in vitro.

1. 45-Ca uptake by pinched-off nerve terminals (synaptosomes) of rat brain incubated in standard physiological saline (including 132 mM-Na + 5mM-K + 1-2 mM-Ca) at 30 degrees C averages about 0-5 mumole Ca per g protein per minute. This may be equivalent to a Ca influx of about 0-03 p-mole/cm-2 sec. 2. The rate of 45-Ca uptake is increased when the concentration of K in the medium is increased above 15-20 mM, K replacing Na isosmotically. Maximum stimulation, a three- to six-fold increase in the rate of Ca uptake, occurs when [K]o is about 60 mM. The effect of increased [K]o is reversible. 3. The K-stimulated Ca uptake is associated primarily with the nerve terminal fraction of brain homogenates. The entering Ca is not accompanied by extracellular markers such as mannitol or inulin. Replacement of external chloride by methylsulphate or sulphate does not prevent the stimulation by K. 4. The effects of external K are quantitatively mimicked by Rb. Caesium also stimulates Ca uptake, but is only about one fifth as effective as K or Rb; Li is ineffective. 5. Two other depolarizing agents also stimulate Ca uptake by synaptosomes: veratridine (7-5 times 10- minus 6 to 7-5 times 10- minus 5 M) and scorpion (Leirus quinquestriatus) venom (6-7 times 10- minus 7 to 6-7 times 10- minus g/ml.). The stimulatory effects of veratridine and scorpion venom, but not of increased [K] are blocked by 2 times 10- minus 7 M tetrodotoxin. 6. Internal K also influences the rate of 45-Ca uptake by synaptosomes: lowering [K]i reduces the stimulatory effect of external K and veratridine. 7. Replacement of external Na by choline markedly inhibits the response to veratridine, but has a much smaller effect on the response to increased [K]o. 8. The Ca uptake mechanism has an apparent dissociation constant for Ca (KCa) of about 0-8 mM. Increasing [K]o increases the maximal rate of Ca uptake, but has no effect on KCa. The K-induced 45-Ca uptake is competitively inhibited by Mg-2+, Mn-2+ and La-3+. 9. The release of acetylcholine and noradrenaline was also studied. Increasing [K]o stimulates external Ca-dependent acetylcholine release. Scorpion venom stimulates noradrenaline release from synaptosomes; this effect could be prevented by adding tetrodotoxin or removing external Ca. 10. These results indicate that synaptosomes may increase their permeability to Ca, accumulate Ca and release neural transmitter substances, when stimulated by depolarizing agents under appropriate physiological conditions.


The influence of sodium on calcium fluxes in pinched-off nerve terminals in vitro.

1. The influence of internal and external Na concentrations on Ca movements have been measured in pinch-off presynaptic nerve terminals (synaptosomes). Ca uptake is enhanced when external Na (Nao) is replaced by Li, choline or dextrose, in Na-loaded synaptosomes. Depletion of internal Na (Nai) abolishes the stimulatory effect of external Na removal. 2. Ca uptake from Na-depleted media is proportional to [Na]i -2, and averages about 1-5 mumole Ca/g synaptosome protein per minute when [Na]i is approximately 137 mM. This may correspond to a Ca influx of about 0-1 p-mole/cm-2 sec. 3. External Na is a competitive inhibitor of the Nai-dependent Ca uptake. The interrelationship between [Na]o, [Ca]o and Ca uptake indicate that two external Na ions may compete with one Ca at each uptake site. 4. The distribution of particles with Nai-dependent Ca uptake activity parallels the distribution of synaptosomes in the preparative sucrose gradient. Thus, this Ca uptake activity is probably a property of the pinched-off nerve terminals per se, and not of the mitochondria which may contaminate the synaptosome fraction. 5. The Nai-dependent Ca uptake mechanism requires an intact surface membrane, since synaptosomes subjected to osmotic lysis lose the ability to accumulate Ca by this route. 6. Ca efflux into Ca-free media is largely dependent upon the presence of external Na. The curve relating Ca efflux to [Na]o is sigmoid, and suggests that more than one external Na ion (perhaps 2 or 3) is needed to activate the efflux of each Ca ion. 7. The net Ca gain exhibited by Na-loaded synaptosomes incubated in Na-depleted media can be accounted for by the increased Ca uptake and decreased Ca loss observed under these conditions. 8. Treatment of synaptosomes with cyanide or 2,4-dinitrophenol decreases Ca uptake and enhances Ca efflux into Na-containing media. This results in a net loss of Ca from the terminals, even in the presence of external Ca. 9. In contrast to the Ca efflux from synaptosomes, the Ca efflux from brain mitochondria is not dependent upon external Na, and is reduced by succinate, a substrate which is known to fuel mitochondrial respiration. 10. The temperature coefficient (Q10) of the Nai-dependent Ca uptake is about 3. 11. The Nai-dependent Ca uptake is reduced at low pH. The relationship between this Ca uptake and pH approximates a titration curve with a pKa of about 5-6. 12. The data indicate that Ca transport in rat brain presynaptic terminals may involve a carrier-mediated Na-Ca exchange mechanism, and that some of the energy required for Ca extrusion may come from the Na electrochemical gradient across the surface membranes.


Preparation of a glycoprotein fraction from pooled human plasma and its evaluation as a substrate for the assay of Clostridium welchii (C. perfringens) neuraminidase.

A glycoprotein fraction (fraction VII) suitable for use as a substrate in assays of microbial neuraminidase was prepared from pooled human plasma. It is pasteurised during preparation to eliminate the risk of transmission of serum hepatitis. This results in polymerisation of some of the gamma1-acid glycoprotein, but fraction VII is shown to be an excellent substrate for the neuraminidase of Clostridium welchii (C. perfringens). A sensitive assay procedure is described. A number of factors may interfere with the measurement of NANA released by the action of microbial neuraminidase and procedures are described for evaluation of this problem. Fraction VII is easy to prepare, cheap and available in standard form in large amounts (inquiries should be addressed to J. K. S.); it is recommended for routine use as a convenient substrate for neuraminidase assays.


A new selective medium for the isolation of Salmonellae other than Salmonella typhi.

A medium consisting of a MacConkey's base with added magnesium, calcium, cobalt, zinc, thiosulphate, novobiocin, iron dextran, Tween 80 and EDTA has been found highly selective for Salmonellaparatyphi B and most of the food poisoning salmonellae that commonly occur in Britain. Nearly all the normal faecal flora is inhibited.


Standardisation of the nitroblue-tetrazolium test.

Optimal conditions for the NBT-reduction test have been sought. Increasing heparin concentrations up to 100 units per ml and a delay in performance of the test, especially when blood specimens are kept at room temperature, resulted in higher values for the NBT index, which then sometimes exceeded the upper limit of normal in healthy people and in uninfected patients. The effect of pH, composition of the buffer, and dye concentration was also investigated. Phosphate-buffered saline pH 7-2 containing 0-1% NBT dye, without glucose, gave the most reliable results. In endotoxin-stimulated NBT tests, the following procedure is recommended: incubation of 0-1 ml whole blood with lyophilised endotoxin 20 mug per ml. for 15 min. in a 37 degree C water bath, followed by the standard test with a 0-2% NBT solution. By this technique, the leucocyte reaction to various types of lipopolysaccharides was of the same order of magnitude. Drug therapy having an effect on blood components lowered this reaction, whatever the source of endotoxin used as stimulant. The importance of NBT-reduction tests is discussed. Standard conditions of test performance are strictly requisite if comparable results are to be obtained and if data not corresponding with the apparent clinical and other laboratory findings are to be evaluated correctly. The stimulated NBT test, performed in parallel with the standard test, is useful in the interpretation of abnormal results and in the detection of factors with a temporary or permanent effect on the phagocytic activity of pmn leucocytes.


A comparative evaluation of the treatment of typhoid fevers with co-trimoxazole and chloramphenicol in Egypt.

Seventy-two patients with bacteriologically proven enteric fever were treated with either co-trimoxazole (41 cases) or chloramphenicol (31 cases). C0-trimoxazole was found to be superior to chloramphenicol in relieving the toxaemia. The average number of days required for patients to become afebrile was 5-5 days in the co-trimoxazole group and 4-5 days in the chloramphenicol group. The cure rate was 97 per cent in each of the treatment groups. There occurred two relapses in the co-trimoxazole group and four relapses in the chloramphenicol group. No side effects of the co-trimoxazole were detected during the study. Co-trimoxazole can be considered as a good alternative to chloramphenicol in the treatment of the enteric fevers.


The undescended testis: management after puberty.

The patient seen after puberty with an intra-abdominal unilateral undescended testis should have orchiectomy. The patient seen after puberty and before the age of 50 years with unilateral undescended testis in the inguinal region should have orchiectomy because the risk of death from malignancy exceeds the risk of anesthesia and orchiectomy.


Nitrofurantoin, sulfamethizole and cephalexin urinary concentration in unequally functioning pyelonephritic kidneys.

Nitrofurantoin, sulfamethizole and cephalexin peak urinary drug concentrations were studied in patients and non-human primates with unequally functioning pyelonephritic kidneys. The peak urinary drug concentration of the poorly functioning kidney in comparison to the better kidney was greater than its percentage relative blood flow or creatinine clearance but variable in its relationship to creatinine concentration, osmolality and sodium concentration. Although for each unit of creatinine clearance the poorly functioning kidney had a higher peak urinary drug concentration than the better functioning kidney, for each kidney the peak urinary drug concentration seemed to be directly proportional to the creatinine clearance, the drug dosage and the renal mechanisms of drug excretion. Nitrofurantoin in the usual recommended dosage did not reach minimal inhibitory urinary drug concentration below a unilateral creatinine clearance of 20 ml. per minute. Whereas, sulfamethizole and cephalexin reached peak urinary drug concentrations greater than the minimal inhibitory concentration at the lowest studied unilateral creatinine clearance of 4 and 11 ml. per minute, respectively.


Serologic evidence of Venezuelan equine encephalitis in some wild and domestic populations of southern Texas.

More than 2,500 sera from approximately 30 wild and domestic species in southern Texas were tested for neutralizing antibodies to Venezuelan equine encephalitis (VEE). Virus isolations were also attempted from blood and tissue samples of many of the wild specimens. VEE neutralizing substances were present in a variety of species collected prior to the 1971 epizootic, suggesting that VEE was present and perhaps enzootic in this area before the recent epizootic. Serologic results of this study suggest that deer (Odocoileus virginianus) and feral swine (Sus scrofa) may serve as good indicators or sentinels of VEE transmission. The reservoir of VEE was not established, but results of the study suggest that a number of species or a combination of animal host populations including deer, feral swine, and peccaries (Pecari angulatus) may be involved in the eizootiologyof VEE in southern Texas.


Spontaneous peritonitis and systemic lupus erythematosus. Importance of accurate diagnosis of gram-positive bacterial infections.

Primary Gram-positive bacterial peritonitis developed in three patients with systemic lupus erythematosus (SLE). These cases suggest a possible association between these two entities. Furthermore, they emphasize the importance of accurate diagnosis when evaluating abdominal symptoms in patients with SLE.


[Clinical course, diagnosis and treatment of idiopathic hypertrophic subaortic stenosis].

Clinical, ECG and X-ray data as well as catheterizational and angiographic data on 20 patients with idiopathic hypertrophic subaortic stenosis were analysed. The problems of medical and surgical treatment of the disease were discussed. The indications for surgical treatment were defined on the basis of the authors' surgical experience (5 operated on patients) and literature data.


[Prognosis of the immediate outcome of myocardial infarct according to data of acid-base and blood oxygen balance].

In 261 patients with acute myocardial infarction an immediate prognosis of the disease was made by using quantitative values of the acid-base and blood oxygen balance, mathematically processed with the help of the analytical method of notion-shaping. The possibility of prognosing in priniciple on the ground of all the factors studied, the blood oxygen tension and the hemoglobin saturation with oxygen being the most informative, was ascertained.


[Treatment of coronary shock].

A brief characteristics of the main therapeutic methods for shock in acute myocardial infarction cases is presented, including fast infusion of plasma-substitutes, noradrenalin, isoproterenol, alpha-adrenergic bocking agents, steroid hormones, intra-aortal balloon counter-pulsation, oxygen therapy, acidbase balance correction, etc. It is emphasized that proper therapy based on the evaluation of the nature of circulatory disorders in every particular case proves effective in some cases.


[Measurement of spontaneous platelet aggregation. Platelet aggregation test III (author's transl)].

A new measuring device for the estimation of the "spontaneous" aggregating activity of thrombocytes has been developed. In this photometric platelet aggregation test (PAT III) a small amount (0.6 ml) of platelet-rich plasma (PRP) is being rotated in a disc-shaped cuvette at 20 rpm, at 37% C. Changes in optical density of PRP which are induced by the formation of platelet aggregates are continuously registered using a chart recorder. The decisive trigger mechanism for aggregation is an increase of plasma pH in the rotating sample which is caused by evaporation of CO2. The results of the test depend on the platelet count in PRP. Aggregation curves are misrepresented by admixture of erythrocytes and lipid turbidity. The tendency of platelets to aggregate increases within 60-90 min following blood sampling. During this period the time interval to the onset of aggregation(Tr) is shortening, and the maximum aggregation speed (alpha2) is increasing. The spontaneously enhanced aggregation tendency of thrombocytes may be reliably measured from 60 min after drawing the blood. The reason for these time-dependent changes which are also demonstrable in ADP-collagen-or epinephrine-induced aggregation is probably the primary shape change of platelets, which occurs after blood drawing and makes them "stickly" and aggregable. PAT III was developed for the detection of enhanced platelet aggregation, indicating  a risk of thrombosis and thromboembolic omplications. The new measuring device  has been designed as "universal" aggregometer. Additional equipment is available for the registration of ADP-collagen-or epinephrine-induced aggregation similar to Born's and O'Brien's methods. The device may be mounted easily on an Eppendorf photometer without further modifications.


The effect of sampling technique on some blood parameters in the rat.

When used to restrain rats while obtaining cardiac blood, there was little difference between the effects of ether, pentobarbitone sodium, and fentanyl plus droperidol on acid-base balance, haemoglobin, haematocrit, plasma protein, calcium and magnesium. The use of manual restraint increased blood acidity, plasma protein, calcium and magnesium, but decreased blood glucose. Haemoglobin and haematocrit values were higher for tail blood than for blood removed from the heart or abdominal aorta.


The effect of sampling technique on acid-base balance and other blood parameters in the sheep.

The effect of 4 sampling routines--venipuncture, intravenous cannula, intravenous cannula following the administration of a tranquiliser (xylidino dihydrothiazine hydrochloride), intravenous cannula following exercise--were compared. Blood pH and base excess values were similar after venipuncture and cannula sampling, but higher (P less than 0 with 05) after the administration of the tranquiliser and lower (P less than 3 with 05) following exercise. Blood haemoglobin, haematocrit and lactate levels followed this pattern, while plasma protein levels were similar for all treatments except after exercise, where they were higher (P less than 0 with 05). The recovery of various blood parameters to normal values after a period of exercise was also studied: acid-base balance had returned to near normal within 60 min, while haemoglobin and haematocrit levels had returned to normal within 10 min.


Self-evaluation of performance and the ability to discriminate blood alcohol concentrations.

Social drinkers who had been trained to discriminate their blood alcohol concentrations (BAC) tended to predict greater impairment of performance while drinking than did untrained controls, although their actual performance on coding tasks did not differ. It is suggested that training in BAC discrimination may enhance caution and concern about behavioral impairment while drinking.


Probability of arrest while driving under the influence of alcohol.

The probability of arrest while driving at a blood alcohol level over 0.10% was .0058 (about 1 in 200).


Effects of alcohol on a Critical Tracking Task.

Performance on a Critical Tracking Task decreased significantly as blood alcohol levels increased.


A self-administered Short Michigan Alcoholism Screening Test (SMAST).

The Michigan Alcoholism Screening Test and a shortened 13-item version can reliably be used as self-administered questionnaires.


Item analysis of the Michigan Alcoholism Screening Test.

The Michigan Alcoholism Screening Test was administered to 200 persons arrested for driving while intoxicated. Most items adequately discriminated between problem and nonproblem drinkers, but several questions assessing severe alcoholism symptoms did not consistenly differentiate between the 2 groups.


Multidisciplinary perspectives on alcoholism and the need for integration. An historical and prospective note.

The history of the recognition of alcoholism as a multidisciplinary social problem from the late 19th century through the evolution of the Center of Alcohol Studies is described, highlightning the men who brought the field prominence. The nature of alcoholism, viewed from an interdisciplinary perspective, is outluned.


Effects of ethanol and ethionine on DNA synthesis during experimental liver regeneration.

Ethanol reversed the ethionine-induced inhibition of 3H-thymidine incoroporation into hepatic DNA in the male and female rat after partial hepatectomy.


Control orientation in alcoholics related to extent of treatment.

The self-perceived locus of control of three groups of alcoholics who had had varying amounts of exposure to treatment was measured on the Internal-External (I-E) scale. Alcoholics who had had more treatment perceived themselves in greater control of their behavior in general and of their drinking in particualar than those who had had less treatment.


Attempted suicide in alcoholics and drug addicts.

Alcoholics who had attempted suicide differed on several demographic variables from addicts to other drugs who had attempted suicide; however; they did not differ on any psychological variable.


Alcoholism and abstinence among relatives of American Indian alcoholics.

The incidence of alcoholism among relatives of Indian alcoholics was significantly greater than it was among relatives of non-Indian alcoholics.


DRL responding by rats during initial and prolonged alcohol administration.

Daily administration of alcohol did not affect the total response rate of rats on a DRL task although alcohol-treated animals made fewer correct (reinforced) responses than did controls.


Adolescent development and the onset of drinking. A longitudinal study.

Junior and senior high-school students were studied over a 4-year period. The likelihood of drinking was directly related to the degree of transition- or problem-proneness, and a developmental relationship between onset of drinking and other socipsychological attributes was found. It is concluded that becoming a drinker is an integral aspect of the process of adolscent development.


Social mobility and alcoholism a comparison of alcholics with their fathers and brothers.

Men alcoholics entered the work force at a low socioeconomic level and though their status gradually increased, it never reached their fathers' or their brothers' level. Downward mobility in relation to significant others seems to play a role in the etiology of alcoholism.


Behavior theraphy in alcoholism. A critical review of broad-spectrum approaches.

A review of the literature in behavior therapy for alcoholism suggests that broad-spectrum approaches based on analysis of the specific stimuli which trigger excessive drinking in individual patients are more effective than conventional methods. It appears too that controlled drinking is a reasonable treatment goal for some alcoholics.


A review of psychologically oriented treatment of alcoholism. II. The relative effectiveness of different treatment approaches and the effectiveness of treatment versus no treatment.

A review of 384 studies of psychologically oriented alcoholism treatment showed that differences in treatment methods did not significantly affect long-term outcome. Mean abstinence rates did not differ between treated and untreated alcoholics, but more treated than nontreated alcoholics improved, suggesting that formal treatment at least increases an alcoholic's chances of reducing his drinking problem.


Quantitative microfluorimetry of formaldehyde induced fluorescence of dopamine in the caudate nucleus.

Quantitative microfluorimetric studies were carried out on the formaldehyde induced fluorescence of dopamine in nerve terminals of the nuc. caudatus putamen using the technique of Falck and Hillarp. After tyrosine hydroxylase inhibition produced by alpha-methyl-p-tyrosine (H 44/68) a time-dependent disappearance of the dopamine fluorescence occurred in an exponential manner, T1/22.6 hr. Apomorphine treatment resulted in a considerable counteraction of the H 44/68 induced reduction of the fluorescence, whereas treatment with haloperidol potentiated it. Administration of gamma-hydroxybutyrolactone led to a marked increase of the dopamine fluorescene. The present microfluorimetric results were in perfect agreement with chemical-analytical determinations of dopamine carried out under identical experimental conditions, and with those reported previously. The fluorescence intensities obtained in the nuc. caudatus putamen were found to be in the linear part of the dopamine fluorescence concentration relationship as observed in protein models. It may be concluded that by using microfluorimetric quantitation of the formaldehyde induced fluorescence in the nuc. caudatus putamen it is possible to obtain a reliable quantitation of the relative amount of dopamine in the dopamine nerve terminals.


Abnormal breathing patterns.

In health, breathing is regular and the respiratory rate is sufficiency constant to be useful as a vital sign of health and disease. This regularity depends on a complex interplay of chemical and neural control systems that operate automatically to reset the rate and depth of breathing as changes occur in posture and activity, to adjust the level of ventilation so that changes in gas tensions and pH in the blood and in the brain intersitial fluid are exceedingly modest despite wide swings in metabolic rate and in environmental conditions, and to coordinate ventilation and circulation so that the requirements of individual tissues for O2 delivery and CO2 removal are satisfied. Two broad categories of disorders can result from malfunction of these systems (Table 1): (1) disproportionate ventilation (too high or too low) for the level of metabolic activity, thereby producing severe abnormalities in blood gas tensions or in acid-base balance, and (2) an irregular breathing pattern without eliciting gross changes in blood gas tensions or in acid-base balance. Because of the complexity of the control system, each of these categories represents a final common pathway that can be produced in different ways. In this presentation, we will attempt to describe the general features that characterize the operation of the control system and some new technics that make it possible to trouble-shoot the malfunctioning system in order to identify the mechanism(s) responsible for the abnormality in breathing pattern.


Mechanism for the paradoxical aciduria following alkali administration to prolonged-fasted patients.

Rapidly induced systemic alkalinization due to either sodium-lactate or sodium-bicarbonate infusion in prolonged-fasted subjects with steady-state ketoacidosis was associated with a decrease in urine pH. This decrease in urine pH from 5.50 to 5.20 was the result of a significant decrease in urinary ammonium excretion from 8.40 to 6.35 mEg/hr and was not accompanied by an increase in net acid excretion (11.3 vs. 10.6 mEg/hr). The decreased ammonium excretion is attributed to the raised pH of the proximal tubular fluid resulting in a less favorable pH gradient for gaseous ammonia entry. This would decrease gaseous ammonia generated in the loop of Henle for collecting duct buffering of secreted hydrogen ions.


The metabolic consequences of adrenergic blockade: a reveiw.

The effects in man of adrenergic blocking agents on plasma insulin, glucagon, growth hormone, and lipid metabolism are reviewed. Whereas basal insulin may be slightly inhibited by beta- and enhanced by alpha-adrenergic blockade, more marked suppression may be achieved under circumstances of high exogenous or endogenous catecholamine stimulation. The relative effects of beta1 or combined beta 1 and beta2 blockers in man are unknown. Glucagon release is probably provoked by beta- and inhibited by alpha-stimulation in man. Muscle glycogenolysis is inhibited by propranolol, and under situations of hepatic glycogen depletion, clinical hypopglycemia may occur. This may also account for the failure of significant hyperglycemia to be observed in short-term experiments on fasting subjects in whom insulin release may be suppressed and glucagon release enhanced. Growth-hormone release is enhanced by beta-adrenergic blockade. Free fatty acid formation in vivo is inhibited by intravenous beta blockade, but the effects of oral administration on triglyceride production and lipoprotein profiles remain uncertain. The inter-relationships between the effects of adrenergic blockade at different sites of hormone and substrate release are unclear but may have important consequences in alteration in carbohydrate tolerance and lipid metabolism. The relative effects of beta-blocking drugs with differing specificity must be determined.


[Examination of the acute effect of prednisolone on the acid secretion of the stimulated gastric mucosa in man].

In comparison with the maximal acid stimulation produced by intravenous infusion of histalog (2 mg/kg bw/h), a single intravenous injection of 25 mg prednisolone during maximal acid stimulation produced by pentagastrin (1.5 mug/kg bw/h) does not cause a significant change of secretion rate or ionic composition of gastric juice in man. This suggests that there is a greater dependence of histalog stimulation than of pentagastrin stimulation on the normal secretion of glucocorticoids.


Culture medium alkalinization by dermatophyes. (Influence of time and temperature of incubation).

95 dermatophyte strains (12 of Trichophyton mentagrophytes, 12 of T. tonsurans, 11 of T. rubrum, 12 of T. megninii, 12 of T. violaceum, 2 of T. schoenleinii, 1 of T. soudanense, 12 of M. canis, 8 of Microsporum gypseum, 1 of M. ferrugineum and 12 of Epidermphoyton floccosum). 1 of Aspergillus niger, 1 of A. ochraceus, 1 of Paecilomyces sp., 1 of Penicillium sp. and 1 of Candida albicans were grown in Sabouraud liquid medium for the study of pH variation over 6 weeks at room temperature and after 4 weeks at 37 degrees C. All the dermatophyte strains alkalinized the medium. The highest pH values after 2-3 weeks' development in room temperature were produced by T. mentagrophytes, M. gypseum and M. canis, and the lowest by T. rubrum and T. violaceum. After the 4th week the alkalinizing activity became more marked for T. mentagrophytes and remained stationary for T. violaceum, In the 5th week the values produced by T. tonsurans were higher than those for M. gypseum, and those for E. floccosum and T. megninii were higher than those of M. canis. A similar behaviour was observed for T. rubrum and T. megninii and for M. canis, M. gypseum and M. ferrugineum. There seems to be a relation between the alkalinizing capacity and the rapidity and amount of the growth. At 37 degrees C both alkalinization and range of variation of the pH values of the medium became more noticeable for the strains of each species.


Beta structures of alternating polypeptides and their possible prebiotic significance.

A survey of the commonest amino acids formed in prebiotic conditions suggests that the earliest form of genetic coding may have specified polypeptides with a strong tendency to form stable Beta-sheet structure. Poly(Val-Lys), like other polypeptides in which hydrophobic and hydrophilic residues alternate, tends to form Beta structures. We show that bilayers with a hydrophobic interior and a hydrophilic exterior may be present in aqueous solution.


Effects of depletion of brain catecholamines during the development of morphine dependence on precipitated withdrawal in rats.

The significance of long term depletion of brain catecholamines (CSs) for the development of morphine dependence and for the expression of morphine withdrawal was studied in rats which were implanted with morphine pellets for 10 days. CAs were depleted by inhibition of tyrosine-hydroxylase with alpha-methyl-tyrosine (AMT) or by destruction of catecholaminergic nerve terminals wit6-hydroxydopamine (6-OHDA). In the "acute" experiments these drugs were  applied within 24 hrs before precipitation of withdrawal; in the "chronic" experiments drug administration was started before the first implantation and in the case of AMT, continued repeatedly thereafter. With either method, "acute" depletion of brain CAs resulted in reduced intensity of withdrawal. When CAs were kept low through the whole time of morphine exposure and also at the time of withdrawal, the intensity of withdrawal was normal in the case of 6-OHDA administration and only slightly decreased in the case of AMT. When AMT administration was discontinued 40 hrs before precipitation of withdrawal the withdrawal pattern occurred with unchanged intensity. Our experimental data are compatible with the assumption that long lasting depletion of brain CAs is compensated for by induction of neuronal supersensitivity for noradrenaline (NA) and dopamine (DA). While both CAs play an important role in the full expression of the withdrawal syndrome their possible involvement in mechanisms leading to dependence seems to be unlikely although final statements cannot be made by the presented experiments.


Localization in the CNA of adrenoceptors which facilitate a cardioinhibitory reflex.

In dogs (pentobarbitone, 25 mg/kg) the brain was removed rostrally to the pons, leaving the cerebellum intact (decerebrate animals). In other animals the cerebellum was additionally removed (bulbar animals). In all animals beta-adrenoceptors were blocked by toliprolol (5 mg/kg s.c.). Angiotensin (0.025-0.3mug/kg) was repeatedly injected i.v. and the resulting maximal reflex bradycardia was recorded. Intracisternal (i.ci.) injection of clonidine, 0.5 to 1 mug/kg, in decerebrate or i.v. injection of 10 or 30 mug/kg in bulbar animals significantly facilitated the reflex bradycardia. This effect was antagonised by a subsequent injection of piperoxan 50 mug/kg i.ci. in decerebrate or 1 mg/kg i.v. in bulbar animals. It is concluded that the facilitatory action of clonidine is mediated by alpha-adrenoceptors within the medulla oblongata.


Dopamine-induced neurogenic vasodilatation in isolated perfused muscle preparation of the dog.

Dopamine, injected into the lumbar aorta of the dog in doses which produce a reversible inhibition of synaptic transmission in the lumbar paravertebral ganglia (0.5-64x10-8 moles), produces a neurogenic vasodilatation in the isolated perfused hindleg or gracilis muscle. This was abolished by acute preganglionic decentralization and by administration into the perfused preparation of alpha-adrenoceptor blocking agents, but not of atropine or diphenhydramine. After decentralization, preganglionic electrical stimulation restored the dopamine-induced indirect vasodilatation. The neurogenic vasodilatation was also seen with intra-aortic injections of epinine (2-32x10-8 moles) and apomorphine (1.2-19.2x10-8 moles) and was preferentially blocked by haloperidol (0.26x10-6 moles). (-)-Noradrenaline, injected into the lumbar aorta in baroreceptor-denervated dogs, was found to be equipotent with dopamine in eliciting the neurogenic vasodilatation; this (-)-noradrenaline-induced effect was preferentially blocked by phentolamine (8x10-6 moles). The possibility that the neurogenic vasodilatation, which occurs upon intra-aortic injection of dopamine in the dog, is due to its gnaglionic-inhibitory effect is discussed.


The influence of imipramine on dopamine-induced ganglionic inhibition and neurogenic vasodilatation in the dog.

Imipramine potentiates the dopamine-induced inhibition in the paravertebral lumbar ganglia of the dog. Potentiation by imipramine of the dopamine-induced neurogenic vasodilatation in the isolated perfused gracilis muscle, is seen in cross-circulation preparations only, where imipramine is injected into the perfusion circuit of an isolated perfused gracilis muscle, it antagonizes the dopamine-induced neurogenic vasodilatation. When imipramine is injected intravenously into a dog with an autoperfused gracilis muscle, the peripheral antagonism masks the potentiating effect at the ganglionic level, and the dopamine-induced neurogenic vasodilatation is abolished.


Further evidence for a cAMP dependent regulation of tyrosine-3-monoxygenase induction in adrenal medulla: effect of denervation.

Unilateral adrenal denervation caused a gradual decrease of adenylate cyclase activity in rat adrenal medulla. The extent of the increase in adrenal medullary 3',5'-cyclic adenosine monophosphate (cAMP) content elicited by injections of carbamylcholine declined gradually folling adrenal denervation. Three or nine days after denervation carbamylcholine caused rise of cAMP and a delayed increase of tyrosine-3-mono-oxygenase (TH) activity of similar magnitude in intact and denervated adrenal medullae. However, after an interval of 15 days or longer following denervation the increase in TH activity elicited by carbamylcholine was greatly reduced. These results support previous proposals that cAMP is involved as a second messenger in the trans-synaptic induction of TH.


Properties of rat cerebral cortex neuronal nuclear surfaces: electrokinetic parameters.

Rat cerebral cortex neuronal nuclei were isolated by a mild technique utilizing sucrose; citric acid was not used in the isolation of the nuclei. These nuclei in 0.0145 M NaC1, 4.5 per cent sorbitol, and 0.6 mM NaHCO3 with pH 7.2 plus or minus 0.1 at 25 degrees C had an electrophoretic morbidity of minus 2.01 mum-s(-1)-V(-1)-cm(-1). The mobility curves for the brain nuclei indicated that the surface had an acid-dissociable group of pK APPROXIMATELY 2.7. Nuclei treated with 50 mg neurominidase/mg particle protein had a mobility of minus 1.4 mum-s(-1)-V(-1)-cm(-1). DNase or RNase at 50 mug/mg protein had no effect on the mobility of the isolated nuclei. Concanavalin A at 50 mug/mg protein decreased the nuclei electrophoretic mobility to minus 1.82 mum-s(-1)-V(-1)-cm(-1). The results are interpreted to mean that the brain nuclear external surface contains terminal sialic acid residues, but it is completely devoid of nucleic acids, and it binds canavalin A.


Cerebellar N-acetyl-beta-D-glucosaminidase: a study of the enzyme in bulk-isolated purkinje and granule cells.

The specific activity of the lysosomal glycosidase N-acetyl-beta-D-glucosaminidase was determined in Purkinje cell bodies and granule cells isolated in bulb from cerebella of 13-, 15- and 18-day-old rats, and somewhat higher values were found for the enzyme in the Purkinje cell bodies. Although the pH profile of N-acetyl-beta-D-glucosaminidase in both neuronal types was similar, the activity in the granule cells exhibited two "pH optima". The glycosidase could be readily solubilized from both neuronal types by repeated freezing and thawing and, upon sedimentation in sucrose density gradients, the solubilized activity appeared as two distinct molecular components. The findings demonstrate the feasibility of detailed and direct comparative studies of neuron-specific patterns of enzymatic development and the excellent suitability of bulk-isolated cells for this purpose.


On the presence of a MSH-release inhibiting system in the rat neurointermediate lobe.

Rat neurointermediate lobes were superfused in vitro and showed a stable secretion rate of MSH after 30 min. MSH secretion from lobes of untreated rats was reversibly inhibited during superfusion with medium containing 45 mM K+. This inhibition could not be induced using lobes from median eminence lesioned or reserpinized rats. Superfusion with 45 mM K+ also induced release of dopamine from lobes preincubated with the labeled transmitter. It is concluded that the MSH-release inhibiting system present in the rat neurointermediate lobe may be identical to the dopaminergic arcuate-intermediate lobe system.


Effects of melatonin on neurotransmitter uptake and release by synaptosome-rich homogenates of the rat hypothalamus.

Preincubation of synaptosome-rich homogenates of rat hypothalamus with melatonin resulted in significant decreases of norepinephrine, serotonin, dopamine and glutamate uptake. Melatonin inhibition was noncompetitive; apparent Km's of initial uptake processes were: (2.5 +/- 0.3) x 10(-7) M for norepinephrine, (2.6 +/- 0.3) x 10(-7) M for serotonin, (2.4 +/- 0.4) x 10(-7) M for dopamine and (1.0 +/- 0.3) x 10(-7) M for glutamate. Apparent Ki's for melatonin inhibition of transmitter uptake were: 0.64 +/- 0.14 mM (norepinephrine), 0.23 +/- mM (serotonin), 0.51 +/- 0.08 mM (dopamine) and 1.21 +/- 0.10 mM (glutamate). Transmitter release evoked by increasing [K+] in medium to 30 mM was augmented by melatonin in a dose-dependent manner. Maximal effects were observed on serotonin release. Accumulation of 3H-melatonin within synaptosome-rich homogenates did not exhibit differences between 0 and 37 degrees C, indicating that the uptake of the hormone was not an active process. These results suggest that exogenously-administered melatonin may affect neurotransmitter accumulation and release in the hypothalamus by modification of the transmitter uptake mechanism rather than by competition with the transmitter for its uptake pump.


Studies on tissue factor activity and production by leukocytes of human umbilical cord and adult origin.

Human adult and umbilical cord-derived leukocytes were shown to be capable of generating tissue factor activity on exposure to endotoxin and to reduced pH. Blood for leukocyte separation was collected from normal adults and from newly delivered sections of umbilical cord and mixed leukocyte preparations were obtained by separation over methyl cellulose Hypaque. The coagulant activity of the cell suspension was assayed using a one-stage or two-stage method. Cord-derived leukocytes were shown to develop greater coagulant activity than adult-derived leukocytes when stimulated by endotoxin in vitro at 2,000 cells/mm-3. This response to endotoxin was partially inhibited by prior exposure of the cells to prostaglandin (PG) E1 an to L-epinephrine. Acetylcholine stimulated the production of coagulant activity in the absence of endotoxin. Both cord and adult-derived leukocytes (20,000/mm-3) developed coagulant activity when exposed to pH reduction by lactic or hydrochloric acids and this activity was shown to be tissue factor.


The enzymes of lecithin biosynthesis in human neonatal lungs. IV. Phosphorylcholine cytidyltransferase.

Phosphorylcholine cytidyltransferase, the enzyme which catalyzes the transfer of phosphorylcholine to cytidine 5'-triphosphate to form CDP-choline, was studied for the first time in human neonatal lung. The assay of product synthesis was linear for 10-20 min and up to 12 mg protein. The pH optimum was 6-6.5. The Km of CTP was 2.0 times 10- minus 3 M, and the Km of phosphorylcholine was 0.25 times 10- minus 3 M. The true Vmax was 10 nmol CDP-choline/mg protein/10 min. The enzyme was stable under frozen conditions. Oxygen had no apparent affect on enzyme activity.


Smallpox vaccination reactions, prophylaxis, and therapy of complications.

Smallpox vaccination in the United States is a routine public health measure which has been under intensive review during the last decade. The most frequently occurring adverse reactions to vaccination are benign and require little or no systemic therapy. These reactions include accidental infection, erythematous and urticarial rash, and generalized vaccinia. Chickenpox occurring concurrently with vaccination presents no problem unless vaccinia has widely superinfected the chickenpox lesions. There is no risk to the pregnant woman who is vaccinated, but there is a slight risk that the fetus will develop fetal vaccinia. The vaccinia does not cause congenital malformations. Vaccinia hyperimmune globulin (VIG) in prophylactic dosage may be given to a pregnant woman who is traveling to a smallpox infected or endemic area in order to prevent fetal vaccinia. Vaccinia necrosum and eczema vaccinatum require vigorous systemic therapy with VIG, and often thiosemicarbazone. Post-vaccinial encephalitis, while frequently serious, has not been shown to be ameliorated by VIG therapy, although there are data which suggest VIG has some value in prophylaxis for encephalitis. Prophylaxis, prompt recognition, and proper therapy may reduce the fatality rates of these complications. Revaccination of patients who have suffered a complication is a frequent clinical problem. Revaccination of an individual who has had post-vaccinial encephalitis or vaccinia necrosum is contraindicated unless the risk of contracting smallpox outweighs the risk of the above two diseases. Revaccination of children who have had eczema vaccinatum is not contraindicated. Revaccination of children with a history of accidental infection or erythematous or urticarial rash presents no known or theoretically increased risk.


Acceptable and controversial approaches to treating the child with learning disabilities.

There are many professionals in multiple disciplines developing approaches for helping children with learning disabilities. Much of these data and reports are published in journals normally not read by physicians. On occasion, such publications are reported in newspapers or lay magazines. Thus, parents may know of ideas and suggestions before the professional. It is understandable that the parent of a handicapped child would continually seek out improved ways of helping his or her child. The treatment of choice is basically special education. Medication will minimize the hyperactivity and distractability; psychotherapy may minimize the emotional effects. However, special educational therapy for the underlying learning disabilities is essential. No one yet has a rapid or "guaranteed" cure. Parents are often caught in the middle. They turn to their physician for guidance. It is the purpose of this paper to review the significant literature in an effort to assist the family physician in providing this guidance.


Necleoside conformations. 19. Temperature and pH effects on the conformation of guanosine phosphates.

Proton magnetic resonance spectra at 250 MHz were measured as a function of temperature and pH of the three guanosine phosphates. From these data and previously published work the conformational parameters of these compounds were determinated. The phosphate group of Guo-5'-P changes its conformation around the C-O bond and its rotation is relatively slow at 20 degrees. At neutral pD the S conformation is favoured and the N form at acid pD. This conformational change is paralleled by a change in exocyclic rotamer distribution and takes place at the pK of the protonation of the base on N-7. Although correlation appears to exist between the various conformations, notable exceptions exist.


Cyclization of uridine monophosphate by diethyl pyrocarbonate.

Reaction between diethyl pyrocarbonate and uridine 2'-phosphate or uridine 3'-phosphate leads to the formation in high yields of uridine 2':3'-cyclic phosphate. This reaction product was identified in experiments involving (a) ultraviolet spectrophotometry, (b) paper chromatography, (c) high voltage paper electrophoresis at both  pH 3.5 and 7.4, (d) acid hydrolysis, and (e) digestion with pancreatic ribonuclease.


The dual action of meclofenamate on the contractile response to PGF2 alpha in the guinea-pig trachea.

Indomethacin and meclofenamate (1 mug/ml) enhance contractile action of PGF2 alpha (5-20 mug) in guinea-pig tracheas superfused with Tyrode solution (5 ml/min). Unlike indomethacin, meclofenamate at a concentration of 10 mug/ml antagonizes contractions of guinea-pig tracheas produced by PGF2 alpha (5-20 mug), while the contractile action of histamine (0-5-2-0 mug) is enhanced. It is concluded that low concentrations of meclofenamate (1 mug/ml) inhibit prostaglandin biosynthesis in tracheal smooth muscles and therefore contractile action of exogenous PGF2 alpha is enhanced, while meclofenamate at a high concentration (10 mug/ml) blocks the receptor sites for PGF2 alpha.


[Participation of thyroxine in the regulation of the rate of isocitrate dehydrogenase reactions in the brain and liver].

A study was made of the effect of thyroxin on the activity of NAD- and NADP-dependent isocitratedehydrogenases in the brain and the liver of chick embryos. It was found that in both of the organs thyroxin accelerated isocitrate oxidation in the mitochondria through the NAD-dependent route and elevated the velocity of the NADP-isocitratedehydrogenase reaction in the citoplasm. At the same time the activity of the mitochondrial NADP-dependent isocitratedehydrogenase increased after the administration of the hormone to the embryos only in the mitochondria of the brain cells; this was apparently associated with the intensive biosynthesis of specific lipids in the developing brain. There was noted a more marked change in the activity of the enzymes in the 18-day embryos, in comparison with the 12-day ones.


Enzymatic S-de-ethylation and the mechanism of S-dealkylation.

An NADPH- and oxygen-dependent enzymatic system responsible for the formation of acetaldehyde from ethylthioethers is present in the 9000 g supernatant fraction of rat liver. This system appears to be quite similar to the one responsible for the formation of formaldehyde from methylthioethers. Although both of these systems appears to be microsomal mixedoxidase systems, several anomalous findings regarding the mechanism of microsomal S-dealkylation have been observed and have led us to the conclusion that the mechanism of this reaction is more complex than originally believed. A scheme is postulated by which an enzyme in the soluble fraction causes microsomal sulfoxidation of alkylthioethers to alkylsulfoxides, followed by metabolism of the alkylsulfoxides to aldehydes.


The effect of cyanate on the clotting proteins and platelet function.

Cyanate reacts with unchanged amino groups of various proteins in a specific irreversible carbamylation reaction. The effect of this molecule on the clotting process and the effects of carbamylation on the clotting proteins and platelet functions were investigated in vitro. An immediate effect on the clotting proteins, not related to pH, was seen in the screening tests prothrombin time, partial thromboplastin time and thrombin time at the highest concentration (100 mM), to a lesser degree at the lower concentration (10 mM). These changes reflected decreases of 19 and 36% respectively in Factor V and X activity, an inhibition of 63-75% of Factors VII, IX, X and XI activity, and 80% inhibition of thrombin activity. The inhibitory changes of carbamylation increased with time. No changes were seen in the activity of Factors I and VIII. Platelet function studies revealed no inhibition of Factor III release; aggregation was abnormal only at high concentrations with epinephrine and collagen induction and partially reversible by resuspension in normal plasma.


Effect of maternal protein deprivation on enzymatic development in newborn rats.

Postnatal development of liver tyrosine aminotransferase and glucose-6-phosphatase, expressed as activity per gram of liver, occurred as rapidly in pups from pregnant rats fed throughout gestation a diet containing only 4% of casein as in pups from those fed the control diet containing 18% of casein supplemented with 0.3% of L-methionine. Total enzyme activity per liver was lower in pups from protein-restricted dams due to their smaller liver size. Dams fed the 4% casein diet during pregnancy gained much less weight than those fed the control diet and produced pups that weighed significantly less than control pups. Reproductive performance of a few dams fed 6% casein diets with or without amino acid supplements during gestation was comparable to that of dams fed the control diet. Litter size was not significantly reduced by the low-protein intake.


Uptake of 67Cu by ceruloplasmin in vitro.

Solutions of human ceruloplasmin, in Tris buffer at pH values between 6 and 7.5, readily took up carrier-free 67Cu2+, but only when the substrate, rho-phenylenediamine, was added.


Unusual venoconstrictor effects of angiotensin II.

Cumulative dose-response curves to angiotensin II were performed on helical strips from canine lateral saphenous vein. Threshold concentrations were in the range of 10(-18)-10(-17)M. Increases in angiotensin from 10(-17)-10(-12)M failed to elicit further increases in tension. Subsequent increases in angiotensin concentration from 10(-11)-10(-7)M again produced dose-related increases in tension. Repeated dose-response curves in the same strips showed reduced maximal response. Responses to low concentrations of angiotensin were attenuated by low concentrations of phentolamine. These results suggest that, at extremely low concentrations angiotensin produced marked contractions in canine saphenous vein strips by releasing endogenous norepinephrine from sympathetic nerve terminals.


Acid-secretory effects of pentagastrin, histamine, urecholine, DBcAMP, and cBMP in isolated stomachs of fed and fasted rats.

Pentagastrin, histamine, urecholine, DBcAMP, and cGMP were all potent stimulants of acid secretion in the isolated stomach of the fed rat. With the exception of histamine and cGMP, all of these compounds were inactive when the stomach of the fasted rat was used. Pentagastrin was most effective when given on the serosal surface while histamine was equally potent whether it was added to the mucosal or serosal surface of the isolated stomach. The test would appear to be a relatively simply, but effective system for studying the basic mechanisms of action of several important secretagogues in the rat.


Isolation and structure assignment of an antimicrobial principle from the volatile oil of Nigella sativa L. seeds.

Refrigeration of the volatile oil of Nigella sativa L. seeds eventuates in a crystalline substance. The chemical structure of the compound was drawn from its chemical behaviour, as well as from its UV, IR, PMR and mass spectral data. The compound was found to be thymohydroquinone: confirmation of the structure was established via the preparation of its corresponding diacetate ester. The compound was found to have high antimicrobial effect against gram positive microorganisms


Intensification of central catecholaminergin and serotonergic processes by the hypothalamic factors MIF and TRF and by angiotensin II.

The  present work deals with the action of MIF (melanocyte stimulating hormone release-inhibiting factor), TRF (thyrotropin  releasing factor), and angiotensin II on the behavioral effects of L-DOPA and of D, L-5-hydroxytrytophan (5-HTP) in mice. The influence of MIF and TRF on the antagonistic effect of L-DOPA of harmine tremors in rabbits was also studied. MIF and TRF, injected i.p., intensify the effects of L-DOPA in mice. The minimal dose of MIF required to induce a +3 response is 0.1 microgram/kg; TRF is active at 500 micrograms/kg. When MIF or TRF are injected into the brain, potentiation of L-DOPA is obtained with exceedingly small quantities of MIF (0.1 pg); the effective dose of TRF is 1 microgram. The behavioral effects of 5-HTP are potentiated by TRF only, at doses of 0.1 microgram/kg, i.p. When TRF is administered intracerebrally, the active dose per mouse is 0.1 ng. Harmine (5 mg/kg i.v.) induced, in the rabbit, sustained whole body tremors; if L-DOPA (5 mg/kg) is  administered i.v. at the peak of the harmine effect, tremors subside. When the rabbit is pretreated with MIF administered i.p. 1 -2 hr before harmine, in doses devoid of an antitumor effect per se (10 micrograms/kg), the L-DOPA antagonism appears at lower dose. Also dopamine (5-10 mg/kg i,v.) proved effective in abating harmine tremors; previous treatment with MIF (50 micrograms/kg) potentiated the antagonistic effect of dopamine. According to the prevailing theories on the mechanism of neurotransmission, some hypotheses will be discussed to explain the observed potentiation: impaired uptake, impaired degradation, interference with the turnover of the boiamines, supersensitivity of the receptors.


Blood pressure response to both carotid occlucion and asphyxia, as influenced by intracerebroventricular injection of norepinephrine or epinephrine.

The carotid occlusion response (COR) in dogs was inhibited by 50 and 58% after intracerebroventricular injection of norepinephrine and hydrochloric acid, both at the pH 2.9. After norepinephrine at pH 7, this inhibition was 22%. The COR inhibition was 24% with epinephrine solution of pH 2.4 whereas the same solution at pH 7 produced no inhibition. The injection of drugs solved in acid solution, lead to a decrease in the pH of the cerebrospinal fluid. The response to asphyxia was inhibited by 50% after injection of norepinephrine at pH 2.9, but not after epinephrine at pH 2.4 or hydrochloric acid. Bradycardia was caused by epinephrine in neutral or acid solution and a decrease of arterial blood pressure was seen after epinephrine or norepinephrine in neutral or acid solution.


Negative surface charge near sodium channels of nerve: divalent ions, monovalent ions, and pH.

Evidence is given for a high density of negative surface charge near the sodium channel of myelinated nerve fibres. The voltage dependence of peak sodium permeability is measured in a voltage clamp. The object is to measure voltage shifts in sodium activation as the following external variables are varied: divalent cation concentration and type, monovalent concentration, and pH. With equimolar substitution of divalent ions the order of effectiveness for giving a positive shift is: Ba equals Sr less than Mg less than Ca less than Co approximately equal to Mn less than Ni less than Zn. A tenfold increase of concentration of any of these ions gives a shift of +20 to +25 mV. At low pH, the shift with a tenfold increase in Ca-2+ is much less than at normal pH, and conversely for high pH. Soulutions with no added divalent ions give a shift of minus 18 mV relative to 2 mM Ca-2+. Removal of 7/8 of the cations from the calcium-free solution gives a further shift of minue 35 mV. All shifts are explained quantitatively by assuming that changes in an external surface potential set up by fixed charges near the sodium channel produce the shifts. The model involves a diffuse double layer of counterions at the nerve surface and some binding of H+ions and divalent ions to the fixed charges. Three types of surface groups are postulated: (1) an acid pKa equals 2.88 charge density minus 0.9 nm- minus 2; (i) an acid pKa equals 4.58, charge density minus 0.58 nm- minus 2; (3) a base pKa equals 6.28, charge density +0.33 nm- minus 2. The two acid groups also bind Ca-2+ ions with a dissociation constant K equals 28 M. Reasonable agreement can also be obtained with a lower net surface charge density and stronger binding of divalent ions and H+ ions.


Binding of tetrodotoxin and saxitoxin to sodium channels.

A useful first step in any chemical characterization of the sodium channels in nerve membrane would clearly be the identification of some measurable property of the channel that does not depend on the intactness of the tissue. To this end, tetrodotoxin and saxitoxin, which bind specifically to sodium channels, have been triated and their binding to rabbit, lobster and garfish non-lyelinated nerve fibres examined. In each case, a component of the binding curve was found that saturated at concentrations of a few nanomolar. In addition, non-specific binding, indicated by a linear dependence of the amount bound on concentration, occurred. A solubilized membrane preparation from garfish nerve shows the same specific binding component as that of the intact nerve. The saturable component of binding seems to reflect the sodium channel density in nerve, and this is extremely small, being about 27/mum-2 in the rabbit nerve and as small as 6/mum-2 in the garfish nerve.


The purity of tritiated tetrodotoxin as determined by bioassay.

The radioactivity binding of a tritiated tetrodotoxin preparation to an electric organ particulate fraction was compared with the binding of biological activity as determined by biological assay. This comparison shows that the chromatographically homogeneous toxin contained a large proportion of radioactive impurities which bind nonspecifically to the electroplax preparation.


The binding of tritiated tetrodotoxin to squid giant axons.

The binding of tetrodotoxin to squid gian axons was determined as a function of toxin concentration, using a tritiated toxin preparation of known radiochemical purity and specific activity. From the amount of saturable binding observed, the number of toxin binding sites thought to be sodium channels was found to be 553 plus or minus 119/mum-2 of axon surface.


The reaction between tetrodotoxin and membrane sites at the node of Ranvier: its kinetics and dependence on pH.

Voltage clamp experiments were done on single nodes of Ranvier to study the inhibition of the sodium permeability by tetrodotoxin (TTX). Equilibrium results could be excellently fitted on the assumption that a sodium channel is blocked when one toxin molecule binds to it, the equilibrium dissociation constant, KT of this reaction being 3.6 nm at 20 degrees C. Onset and offset of block could be quantitatively interpreted to be determined by the rates of the TTX-channel reaction whose average constants, at room temperature, were 3 times 10-6M-minus 1s-minus 1 for the association (k1) and 1.4 times 10-minus 2 s-minus 1 for the dissociation (k2). The dependence of the constants on temperature could be described by Arrhenius plots yielding activation energies of 29.3, 85.5 and 41.0 (57.3) kJ/mol for KT, k2 and k1 (K1 derived from onset alone), respectively. At low pH the relative TTX effect was clearly less than at neutral pH. These results could be explained by a model involving the competition of TTX and protons for the same receptor to which protons bind as a function of membrane potential.


The rate of action of tetrodotoxin on sodium conductance in the squid giant axon.

When tetrodotoxin is applied to or washed away from the squid giant axon, the rates at which the sodium conductatnce is blocked and unblocked are an order of magnitude smaller than those reported for the isolated node of Ranvier. This slowing is to be expected if in squid the tetrodotoxin binding sites act as a saturable sink in series with the barrier to free diffusion imposed by the presence of the Schwann cell. A comparison has been made between the rates observed experimentally and those calculated for a computer model of the system, in order to estimate the apparent density in the membrane of both specific and non-specific tetrodotoxin binding sites. The figure thus obtained for the number of sodium channels in the squid giant axon, several hundred per square micrometre, agrees well with those derived from other lines of argument.


Calcium currents in squid giant axon.

Voltage-clamp experiments were carried out on intracellularly perfused squid giant axons in a Na-free solution of 100 mM CaCl2+sucrose. The internal solution was 25 mM CsF+sucrose or 100 mM RbF+50mM tetraethylammonium chloride+sucrose. Depolarizing voltage clamp steps produced small inward currents; at large depolarizations the inward current reversed into an outward current. Tetrodotoxin completely blocked the inward current and part of the outward current. No inward current was seen with 100 mM MgCl2+sucrose as internal solution. It is concluded that the inward current is carried by Ca ions moving through the sodium channel. The reversal potential of the tetrodotoxin-sensitive current was +54mV with 25 mM CsF+sucrose inside and +10 mV with 100 mM RbF+50 mM tetraethylammonium chloride+sucrose inside. From the reversal potentials measured with varying external and internal solutions the relative permeabilities of the sodium channel for Ca, Cs and Na were calculated by means of the constant field equations. The results of the voltage-clamp experiments are compared with measurements of the Ca entry in intact axons.


Voltage-dependent changes in the permeability of nerve membranes to calcium and other divalent cations.

Transmitter release from depolarized nerve terminals seems to be preceded by a rise in the intracellular concentration of ionized calcium. In squid giant axons, depolarization promotes calcium entry by two routes: one that is blocked by tetrodotoxin and one that is insensitive to tetrodotoxin. The TTX-sensitive route seems to be the sodium channel of the action potential; but the TTX-insensitive route seems to be quite distinct from the sodium and potassium channels of the action potential. It is blocked by Mg-2+, Mn-2+ and Co-2+ ions and by the organic calcium antagonist D-600 and has many features in common with the mechanism that couples excitation to secretion.


The optical spike.

Among the signs of activity in excitable membranes, the action current (electrical spike) has been extensively studied. Recently, a new approach with optical methods has been rewarding. In nerves, a transient, rapid change of light scanning, birefringence and induced fluorescence can be observed during the passage of the action current. These optical effects are synchronous with the electrical spike and are therefore called the optical spikes. Birefringence decreases during excitation in the giant axon of the squid, the walking nerves of Maia, the vagus nerve of the rabbit, but it increases in the olfactory nerve of the pike, which contains 4 million nonmedullated nerve fibres. Light scattering increases or decreases depending on the angle of observation. Vitally stained nerves with fluorescent probes show an increase and a shift in the wavelength distribution of the fluorescent spike.


Heat production non-myelinated nerves.

Experiments with the C fibres of the rabbit vagus nerve have established that heat is evolved during the depolarizing phase of the action potential and is absorbed during the repolarizing phase. Subsequent studies using the pike olfactory nerve indicate that the heat production begins at a high rate very early in the depolarizing phase and is completed in advance of the peak of the spike. This would be expected if the heat arised from the energy released by the discharge of the membrane capacitance which varies as the square of the membrane potential; but estimates of the stored energy fall short of the observed heat production by a factor of two or three times. The prominent cooling phase suggests that a substantial part of the heat may arise from an entropy change. Such an entropy change would be expected to result from the change in the electrical stress in the dielectric of the membrane capacitance, and may thus be manifestation of reversible changes in the molecular architecture of the insulating matrix of the membrane.


Potential-dependent conductances in lipid membranes containing alamethicin.

This article is concerned primarily with the mechanism of the potential-dependent conductance induced in artificial lipid membranes by the cyclic polypeptide andibiotic alamethicin. It has already been shown from studies of the fluctuations that can be detected in very small membrane currents that alamethicin forms transient pores of some 0.6 nm in diameter and that, for small inorganic ions, these are poorly selective. The origin of these pores, their spatial distribution and interaction are discussed. It is demonstrated that the sensitivity of the membrane conductance to the applied potential arises only to a slight extent from the current-voltage relations for the individual pores, and that the main effect stems from the influence of the potential on the frequency of opening of the pores. From the properties of lipid membranes containing alamethicin in a wide variety of electrolytes, and from other evidence, it is concluded that the polypeptide reacts to the electric field more probably because it has dipole moment than because it binds ions. It is proposed that the conducting complex is capable of functioning in either of two orientations, and that it is these two possibilities that give rise to certain differences in the single channel characteristics for the two directions of the field.


Kinetic properties and inactivation of the gating currents of sodium channels in squid axon.

Associated with the opening and closing of the sodium channels of nerve membrane is a small component of capacitative current, the gating current. After termination of a depolarizing step the gating current and sodium current decay with similar time courses. Both currents decay more rapidly at relatively negative membrane voltages than at positive ones. The gating current that flows during a depolarizing step is diminished by a pre-pulse that inactivates the sodium permeability. A pre-pulse has no effect after inactivation has been destroyed by internal perfusion with the proteolytic enzyme pronase. Gating charge (considered as positive charge) moves outward during a positive voltage step, with voltage dependent kinetics. The time constant of the outward gating current is a maximum at about minus 10 mV, and has a smaller value at voltages either more positive or negative than this value.


On the relation between displacement currents and activation of the sodium conductance in the squid giant axon.

The early time course of the current passing across the membrane in squid giant axons in which the ionic currents have been blocked reveals substantial asymmetries during and after the application of hyperpolarizing and depolarizing voltage-clamp pulses of identical size. Since the integral of the 'on' and 'off' current transients is zero, these currents must result from charge movements confined to the membrane and, therefore, they are nonlinear displacement currents. The steady state rearrangement of the charges as a consequence of sudden displacements of the membrane potential is consistent with a Boltzmann distribution of charges between two states characterized by different energy levels. Following changes in membrane potential the charges undergo a first order transition between these states. The relaxation time constant for the transition at a given temperature is a function of membrane potential. We propose that these displacement currents arise from a redistribution of the charges involved in the sodium gating system.


Gating currents in the node of Ranvier: voltage and time dependence.

Like the axolemma of the giant nerve fibre of the squid, the nodal membrane of frog myelinated nerve fibres after blocking transmembrane ionic currents exhibits asymmetrical displacement currents during and after hyperpolarizing and depolarizing voltage clamp pulses of equal size. The steady-state distribution of charges as a function of membrane potential is consistent with Boltzmanns law (midpoint potential minus 33.7 mV; saturation value 17200 charges/mum-2). The time course of the asymmetry current and the voltage dependence of its time constant are consistent with the notion that due to a sudden change in membrane potential the charges undergo a first order transition between two configurations. Size and voltage dependence of the time constant are similar to those of the activation of the sodium conductance assuming m-2h kinetics. The results suggest that the presence of ten times more sodium channels (5000/mum-2) in the node of Ranvier than in the squid giant axon with similar sodium conductance per channel (2-3 pS).


Asymmetry currents in intracellularly perfused squid giant axons.

Asymmetry currents were recorded from intracellularly perfused squid axons subjected to exactly equal positive and negative voltage clamp pulses at a temperature close to 0 degrees C. The voltage and time dependence of the asymmetry currents was studied at a holding potential of minus 80 to minus 100 mV. The effect of varying the holding potential was investigated. The latter experiments showed that the voltage dependence of the asymmetrical charge movement is different from the voltage dependence of the m system.


Charge movements in skeletal muscle.

In twitch muscle, an action potential propagating along the surface can lead to mechanical contraction of the entire cross section of the fibre. The processes involve a depolarization of the membranes of the transverse tubular system which, in turn, causes a release of calcium from its intracellular storage location, the sarcoplasmic reticulum. It seems that a change in potential across the first structure can trigger the release from the second, adjacent structure. If the time and voltage dependent ionic currents are blocked, small movements of charge can be detected when a fibre is depolarized from a normal resting potential to a potential at which contraction is activated. These charge movements, which do not behave as currents passing through ionic channels, may be part of a trigger mechanism.


Observations on intramembrane charge movements in skeletal muscle.

Using signal-averaging techniques, one can record small membrane currents which remain even after blockage of the ionic currents which accompany electrical excitation in muscle. These residual currents probably represent the reorientation of charged molecules inside the membrane in response to a change in membrane potential. Two operationally separable types of intramembrane charge movement in muscle are described, one of which may play a role in excitation-contraction coupling. Studies of tetrodotoxin binding to muscle indicate that "sodium gating current" is unlikely to contribute significantly to either type of charge movement.


Steady state current rectification in potential clamped nodes of Ranvier (Xenopus laevis).

The membrane potential in single nodes of Ranvier was changed in rectangular pulse steps while the membrane currents, associated with the potential steps, were measured. Changes were made in the ionic composition of the external and the internal medium. The latter changes were obtained by free diffusion through a cut internode. The steady state currents, described on the basis of potassium and leak permeability, were affected by the solution composition in a characteristic way. Increased inside concentration of sodium and lithium caused a striking rectification of the outward steady state currents at large potential steps. Instantaneous potassium currents in high [K+]o at a second potential step to E approximately equal to minus 80 mV were not affected by [Na+]1. Neither [Na+]o nor [K+]i affected the potential at which this rectification appeared. Increased [K+]o shifted the region for rectification along the potential axis in positive direction. These findings form strict limitations for satisfactory models describing the mechanism for the steady state current in myelinated nerve.


Adrenergic control of cardian pacemaker currents.

Pacemaker activity in atrial muscle and in Purkinje fibres is generated by a time-dependent decay of potassium current that allows the membrane to be depolarized to the threshold for action potential initiation. The kinetics of the pacemaker potassium currents in these two parts of the heart are sufficiently different to indicate that they correspond to different membrane structures. This conclusion is strengthened by the discovery that the mechanisms of acceleration produced by adrenaline are also quite different. In Purkinje fibres, the activation threshold for the potassium current is shifted in a depolarizing direction with no change in maximum amplitude. This voltage shift is adequate by itself to explain the acceleration. In atrial fibres the pacemaker potassium current is increased in amplitude with no shift in threshold. By itself, this action of adrenaline would slow pacemaker activity and the acceleration in this case is dependent on a large increase in the current attributable to calcium ions. The roles of cyclic 3',5'-AMP and of intracellular calcium ions in mediating the pacemaker actions of adrenaline will also be discussed.


Fluorescent probes in membrane studies.

A number of spectroscopic techniques are suitable for studying biological membranes. Of these, fluorescence has the sensitivity and time resolution for following membrane events associated with nerve excitation. In this paper, the nature of the information derived from measurements of the fluorescence properties of externally introduced chromophores in membranes is examined. In particular, the locations of various probes are described on the basis of nuclear magnetic resonance (n.m.r.) experiments in model situations. Then the motional characteristics of the probe molecules (rotation and diffusion) are discussed. Finally experiments designed to relate the detailed observations that can be made in lipid bilayers using n.m.r. and fuorescence measurements to those (more limited in nature) that can be made in membranes are described.


Acetylcholine receptors.

Alpha-Bungarotoxin is one of a class of proteins, isolated from snake venoms, which antagonize the action of acetylcholine at vertebrate neuromuscular junctions and 'electroplaques' of electric fish. Alpha-Bungarotoxin blocks acetylcholine action irreversibly and may be labelled with either 125I or 3H. This irreversible binding is used as the basis of an in vitro assay for acetylcholine receptors, whether in intact tissue, membrane fragments or solubilized preparations. Acetylcholine receptors from Torpedo and denervated skeletal muscle have been solutilized and substantially purified using affinity chromatography. The distribution of acetylcholine receptors in several tissues has been determined, and an auto-immune response, induced by injection of purified Torpedo receptors, has been studied.


The influence of pH in the medium on degradation of neurohormones by pregnancy serum.

The authors studied the dynamics of natural substrates of neurohumoral origin (oxytocin and lysine-vasopressin) by the serum of pregnant and nonpregnant women in relation to the pH in the medium, within pH limits of 2.5 to 8. The values obtained in a polarographic study of depression of the complex oxytocin and lysine-vasopressin polarographic wave by pregnancy and non-pregnancy sera and the results of a parallel analysis of free amino acids of the inactivated substrates under the same conditions showed that, apart from deep degradation of the studied substrates at the optimum pH (5.5 minus 8), less pronounced degradation of the molecule at low pH values (3 minus 4,5), i.e. in a non-physiological blood medium, also occurred. On the basis of their results, the authors submit the hypothesis of the existence of oxytocinase isoenzymes and of the probable presence of several peptidases with overlapping specificity.


Development of the cerebrospinal fluid in chick embryos. Physicochemical properties.

The development of the physicochemical properties of the cerebrospinal fluid (CSF) was studied in chick embryos from the 9th day of incubation up to hatching. Some of these properties were compared with the corresponding blood or blood plasma properties. During the second half of incubation the CSF pressure rose from 13.2 plus or minus 0.18 mm H2O in 9-day-old embryos to 80.7 plus or minus 0.48 mm H2O just prior to hatching. The critical stages of this development were the 13th to 15th and the 19th to 21st day of incubation. In 13- and 15-day-old embryos, CSF pressure fell sharply after the intracerebral injection of ouabain, but in 19-day embryos it was unaffected. Except for the 15th and 19th incubation day, the CSF pH was always lower than the plasma pH. From the 11th day of incubation up to hatching, the CSF pH fell from 7.36 plus or minus 0.002 to 7.2 plus or minus 0.005. On the 11th and 13th day, specific CSF resistance was higher than plasma resistance, whereas from the 17th incubation day it was significantly lower than the plasma value. During the second half of incubation, specific CSF resistance fell from 1.059 times 10(6) to 0.824 times 10(6) omega mm.m(-1). A difference between the D.C. potential of the venous blood and the CSF appeared for the first time in 15-day-old embryos, the CSF being negative in relation to the blood. By the end of the incubation period this potential difference rose to 10.82 times 0.07 mv.


Separation of mouse spleen haematopoietic cell fractions for transplantation purposes in lethally irradiated mice.

Mouse cells were fractioned by adherence chromatography on glass beads. The fractionation of spleen cells yielded 5 different fractions, whose transplantation effect was tested by the method of Till and McCulloch. The results of these transplantation tests showed that the chosen form of adherence chromatography was not sufficiently successful, since none of the resultant fractions contained solely colony-forming units (CFU) and in none of them were CFU present in an exeptionally high concentration.


Clinical and experimental comparison of diazepam, chlorazepate and placebo.

A double blind clinical evaluation of chlorazepate (dipotassium-7-chloro-5-phenyl-2,2-dihydroxy-3-carboxy-1,2-dihydro-2H-1,4-benzodiazepine), diazepam and placebo on a patient group of young students, mean age 25 years, is reported. Both drugs were significantly better than placebo and according to global assessment chlorazepate was superior to diazepam. An analysis of the main target symptom revealed better effects of chlorazepate on the following items: anxiety, feeling of muscular tension and gastro-intestinal disturbances. With respect to irritability and sleep disturbances both drugs were found to be equally effective. In patients' self-ratings chlorazepate was considered superior to diazepam in giving more alertness and less drowsiness during day time. The results are discussed with reference to EEG-studies and pharmaco-kinetic properties of chlorazepate and diazepam. Performance tests in simulated car-driving by healthy volunteers did not demonstrate any significant difference as compared with placebo. The psychophysiological eeffects, however, are more pronounced after diazepam than after chlorazepate medication.


The acute effects of intravenous infusion of parathyroid hormone on urine, plasma and saliva in the sheep.

Following an intravenous loading injection of 75 U.S.P. Units of Para-Thor-Mone (Eli Lilly and Co), seven conscious, non-pregnant, non-lactating Merino ewes were infused with a maintenance dose of the hormone at a rate of 4-75 U.S.P. units/min for 2 hr. The classical hypercalcaemia and hypophosphataemia of the non-ruminant was observed, but the hypercalcaemi- was only small. Plasma potassium concentration decreases, while there were no changes in plasma sodium, chloride or mangesium. The classical phosphaturic effect of the hormone was not observed, only trace amounts of phosphate being exreted throughout the experiment. Urinary excretion of calcium and magnesium decreased, urine flow and urinary excretion of sodium, potassium, chloride, bicarbonate and urine pH increased. Glomerular filtration rate was unaffected, but renal plasma flow increased. The concentration and secretion rate of salivary phosphate increased markedly. Changes in the other important salivary electrolytes (sodium, potassium, chloride, bicarbonate and hydrogen ion) also occurred, but it was difficult to separate primary from secondary effects of the hormone. Saliva flow rate increased transiently following hormone injection, but the effect was not sustained by the maintenance infusion.


Histochemical development of myofibres in neonatal piglets.

The periodic acid-Schiff (PAS) reaction and tests for glycogen phosphorylase, oxidative enzymes and acid-stable and alkali-stable adenosine triphophatase (ATPase) were used to determine the degree of histochemical differentiation between myofibres of sartorius muscles from neonatal piglets. Within 24 h of birth, the ratio of myofibres with acid-stable ATPase to those with acid-labile ATPase was 1:21-0. By 10 days the ratio had changed to 1:5-2. Mean minimum myofibre diameters (all histochemical types combined) increased steadily after birth although diameters of myofibres with acid-stable ATPase showed no increase until 6 days. By 10 days, consistent differentiation was observed with the alkali-stable ATPase and glycogen phosphorylase reactions but not with the PAS reaction. During the 10 day neonatal period, all types of myofibres contained large or moderate numbers of mitochondria.


[Induced beta-adrenergic stimulation and blockade in asthma bronchomotor effects (author's transl)].

Patients with asthma, exhibiting spontaneous bronchial obstruction, from mild to medium severity, were examined by body plethysmography. Results were expressed as specific airway resistance (SRaw) in preference to specific conductance, the latter leading to errors, in particular in cases with dissimilar baseline values. After the inhalation of a beta-stimulating drug (salbutamol), the decreases in SRaw was directly related to initial SRaw, either in a group (n equal 30) or in individual cases. After the injection of a beta-blocking drug (propranolol), the increase in SRaw, found abnormal in 60% of the subjects, could be related to initial SRaw neither in a group (n equal 40) nor in individual cases. These findings indicate that submaximal bronchial obstruction in patients with asthma is mainly due to a bronchoconstriction, whatever the degree of the obstruction may be. On the opposite, there is an increased bronchodilator adrenergic influence in a majority of patients, not predictable after the degree of initial airway obstruction.


The carbamate equilibrium of bovine hemoglobin at 37 degrees C.

emoglobin-bound CO2 was estimated by a procedure first described by Rossi-Bernardi et al. (1969) in which the carbamate compound is stabilized by rapid mixing with alkali and then separated from other CO2 constituents in solution by gel filtration and ion-exchange chromatography. Carbamate equilibrium of bovine hemoglobin was studied at constant PCO2 (44 mm Hg) and varying pH as well as at constant pH (7.4) and varying PCO2 (ionic strength 0.18, temperature 37.0 degrees C). The difference in Z (deltaZ) between hemoglobin and oxyhemoglobin appeared to be 0.11 plus or minus 0.04 (pH=7.40; PCO2=44 mm Hg) i.e. about half the value observed in human hemoglobin. DeltaZ was shown to account completely for the difference in CO2 content (CCO2) between hemoglobin and oxyhemoglobin when in total equilibrium with CO2. Carbamate determinations on bovine hemoglobin specifically modified at all terminal amino groups (double-blocked carbamylated derivative) did not show any CO2 binding at all, thus giving a final proof for the exclusive role of the terminal amino groups in CO2 binding under physiological conditions. Attempts to calculate the ionization constant (Kz) and the carbamate equilibrium constant (Kc) of the terminal amino groups failed, suggesting that both terminal groups are not equivalent in their CO2 binding properties. This was confirmed by the fact that carbamate data obtained at constant PCO2 and varying pH fitted binding curves derived from two sets of independent but non-equivalent binding sites. Association constants for both kinds of binding sites appeared to differ by a factor of at least 3 in hemoglobin and of about 10 in oxyhemoglobin. From determinations of hemoglobin-bound CO2 and CO2 content of hemoglobin and oxyhemoglobin solutions in total equilibrium with CO2, the apparent first dissociation constant of carbonic acid was calculated as 5.71 plus or minus 0.0061 pH and found to be independent of the oxygenation state of hemoglobin. In contrast with hemoglobin of other species bovine hemoglobin appeared to be not influenced by the presence of 2.3-diphosphoglycerate as far as its CO2-binding properties are concerned.