[Investigation of rat brain prealbumins]. 12 prealbumines of rat brain water-soluble fraction were studied. Neither lipid components nor carbohydrate ones were found out in the proteins. Three of the proteins appeared to be RNA-proteids. Their subcellular distribution was investigated. The effects of temperature, salts, acids and ethanol on disc electrophoretic spectrum of brain prealbumines were closely observed. The amino acid composition, properties, compartmentation, tissue and species specificity of one of the prealbumines were studied in detail. The protein is marked as BTB-protein, as it migrates under disc electrophoresis in 7,5% polyacrylamide gel with the "witness" front of bromothemol blue (BTB). The content of BTB-protein is 0.06--0.08 gr per 100 gr of wet tissue. The protein is RNA-proteid. Its molecular weight is 10,000--20,000. BTB-protein contains 42 mole % of acidic amino acids and 5.4 mole % of alkaline ones. The protein was found in nuclear and cytoplasmic fractions. It is mainly an all-organs protein. Small amount of this protein is found in blood serum. BTB-protein can be found on the disc electrophoregramms of embryo and newborn rats brain proteins, as well as of the brain of other mammals, birds and amphibia. BTB-protein is resistant to boiling and to the effects of salts, acids, ethanol. It is suggested that BTB-protein has heterogenous structure and may be of neurophysin nature.


[Inhibition of mouse spleen inorganic pyrophosphatase by methylene diphosphonic acid]. Some properties of mouse spleen cytosol inorgainc pyrophosphatase (PPi-ase) (E. C. 3.6.1.1) as well as the effect of methylene diphosphonic acid (PCP) on the PPi-ase activity were studied. Specific staining for the enzyme PAAG disc-electrophoresis was developed; it was shown that the PPi-ase formed only one band in 7.5% PAAG. The enzyme pH optimum being 8.0, the optimal [Mg++]/[PPi] ratio was about 2; Km =7.7x10(-4) M, Vmax=0.77 mkM. min-1. mg protein-1. PCP was shown to competitively inhibit the pyrophosphatase reaction, Ki=2.5x10(-4) M +/- 0.2x10(-4) M.


[The role of the tryptophan-62 residue in the structure and function of lysozyme]. The thermostability and thermodinamics of formation of the enzyme-substrate complex of two oxidation products of chicken egg lysozyme with the tryptophane-62 residue modified to N'-formylkinurenine (with 2.5% activity) and kinurenine (with 27.5% activity) have been studied. In thermostability and pH effect on the substrate binding the lysozyme oxidation products do not differ from native lysozyme. The data obtained and thermodynamical characteristics of the enzyme-substrate complex formation suggest that the chemical nature of the 62 residue does not significantly affect the  conformational properties of lysozyme, however, having a strongly pronounced effect on the binding of substrate and hence the total enzyme activity.


[Study of rat brain tissue nucleases].

[Study of rat brain tissue nucleases]. Acid and alkaline nucleases of the brain tissues have been identified and partially purified. Alkaline DNA-ase hydrolyzing denatured DNA at pH 8,0; alkaline RNA-ase having optimal activity at pH 8,0 and nuclease intensively hydrolyzing both DNA and RNA at pH 5.0. The molecular weights of these enzymes have been determined.


[Purification, properties and quaternary structure of glutamine synthetase from Chlorella]. A highly purified preparation of glutamine synthetase from chlorella grown on a medium containing nitrate as a sole source of nitrogen, was isolated and characterized by disc-electrophoresis and analytical ultracentrifugation. The N-terminal amino acid of glutamine synthetase is glycine. The molecular weight of glutamine synthetase is 32.000; its activity in the presence of Mg2+ was 150 mkmol o-phosphate per min per mg protein. The molecular weight of subunits of the enzyme, equal to 53.000 was determined by disc-electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate. Electron microscopy of negatively contrasted enzyme preparations revealed 6 subunits in the enzyme molecule, arranged in a point symmetry group 32.


[Some physicochemical properties of modified trypsin]. Physico-chemical properties of trypsin covalently bound with human serum albumin by glutaric aldehyde have been studied. The modification of the enzyme practically caused no changes in the pH optimum of trypsin. The inhibition of modified trypsin by inhibitors from soy beans and human blood serum has been also studied. The apparent inhibition constants have been calculated. The modification has been shown to result in a deceleration of autolytic degradation. The autolysis rate constants have been calculated at 50 degrees C.


[Fractionation and purification of endo-1,4-beta-xylanases and exo-1,4-beta-xylosidases of Aspergillus niger]. Two endo-1,4-beta-zylanases (m. w. 24,000 and 41,000) and six exo-1,4-beta-xylosidases, differing in their molecular weights and isoelectric points, were found in a xylanase preparation from Aspergillus niger, using different methods of fractionation. An electrophoretically homogeneous exo-1,4-beta-xylosidase (m. w. 30,000) purified 120-fold, with pI 4.6, having optimal effect on methyl-beta-D-xyloside at pH 3.0 was obtained. Exo-1,4-beta-xylosidase splits off xylose from the ends of the xylan chains at xylotriose, xylobiose and methyl-beta-D-xyloside and is characterized by a high transglycosilase activity. An electrophoretically homogeneous endo-1,4-beta-xylanase (m. w. 24,000) purified 250-fold, with pI 4.2 and optimal effect on carboxymethylxylan at pH 4.2 was isolated. Endo-1,4-beta-xylanase splits arabinoglucuronoxylan to form xylooligosaccharides; however, it does not hydrolyze xylobiose.


[Enzymatic properties of immobilized beta-galactosidase from Curvularia inaequalis]. beta-Galactosidase (EC 3.2.1.23) from fungus Curvularia inaequalis was modified by active brilliant orange KH and adsorbed on DEAE-Sephadex A-50. The lactose hydrolysis was studied in a continous flow on the column packed with the immobilized enzyme. The pH and temperatures optima for the substrate hydrolysis by the immobilized enzyme were shown to remain unchanged. A certain destabilizing effect of the matrix on the enzyme resistance to hear denaturation was observed. The activation parameters of denaturation of the native enzyme as well as those of the dye-modified and immobilized preparations were determined.


[Use of sedimentation under conditions of acidic denaturation for the determination of molecular weights of RNAs]. The conditions for acidic denaturation of double stranded RNA were found. Under these conditions a limited degradation of high molecular weight viral RNA took place. This degradation was determined by the degree of fragmentation and loss of infectivity at acidic conditions. It was found that acidic denaturation of RNA in the solutions of low ionic strength was accompanied by a considerable increase of sedimentation coefficient. Under these conditions the coefficients of sedimentation and molecular weights of RNAs studied are connected by the following function S20=2.84-10(-2) Mr0.689. The conclusion has been drawn that the sedimentation under the conditions for acidic denaturation could be used both for molecular weight determination and the practical preparation of unaggregated strands of RNA.


[Purification and properties of phototrophic bacteria Thiocapsa roseopersicina hydrogenase bound with chromatophores]. The method of solution and puridication of hydrogenase from chromatophores of purpur sulphur bacteria Thiocapsa roseopersicina strain BBS are described. Hydrogenase molecular weight is 73000. It contains 4,4 mole S2- and 3.1 mole Fe2+ per mole of protein; pI 4.15. The enzyme absorption spectrum has the maximun et 400-410 nm, which is characteristic of proteins containing non-haem iron. Membrane--linked enzyme as well as soluble hydrogenase of that microorganism is characterized by high thermal stability: inactivation occurs at the temperature above 78 degrees C when the optimal temperature for that enzyme is 70 degrees C. Homogenous enzyme catalyses D2--H2O exchange reaction, reversible redox reaction of methyl viologene and benzyl viologene.


[Conformation study of cyclic adenosine-3',5'-monophosphate and some of its derivatives by means of circular dichroism]. Circular dichroism spectra of adenosine and cyclic adenosine-3',5'-monophosphate (cAMP) and their derivatives, having different substituents in 8-position of heterocycle, are studied, cAMP is suggested to have preferable anti-conformation in the solution, while its derivatives with substituents in 8-position of purine base are preferable in sin-conformation. An exception is 8-(beta aminoethylamine-)cAMP, which has an anti-conformation within pH range from 4.5 to 9.5. This is probably due to the formation of intra-molecular ionic bond between cyclophosphate group and aliphatic amino group of 8-position substituent.


The relationship between epilepsy and schizophrenia: a biochemical hypothesis. There has been much controversy in the past surrounding the relationship between schizophrenia and epilepsy. One hypothesis has been that the two disorders are antagonistic. The evidence supporting the antagonism hypothesis is briefly reviewed. A new theory based on current knowledge of the relationship of dopamine to both disorders is postulated which may explain the relationship between the psychosis and epilepsy which occurs in a subgroup of schizophrenic patients. In the light of this hypothesis it is suggested that further clinical work be undertaken to clarify further the exact association between the two disorders.


High and low affinity Ca2+ binding to the sarcoplasmic reticulum: use of a high-affinity fluorescent calcium indicator. The fluorescent calcium indicator, calcein, has been used as a high-affinity indicator of Ca2+ in the aqueous phase at physiological pH in the study of high-affinity calcium binding to sarcoplasmic reticulum (SR). The binding constant of the indicator at physiological pH is 10(3)-10(4) M-1 and increases with increasing pH. The binding mechanism of the indicator with Ca2+ and Mg2+ is described. Application of calcein as an aqueous indicator of Ca2+ binding to the SR at room temperature has revealed two classes of binding sites: one with high capacity and low affinity (ca. 820 nmol/mg protein, Kd = 1.9 mM), and another with low capacity and higher affinity (ca. 35 nmol/mg protein, Kd = 17.5 micronM). The divalent cation specificity of the low-affinity  site is low and Ca2+/Mg2+ specificity of the high-affinity site is high. Quantitative studies of the bindings indicate that the high-affinity site residues in the Ca2+ ATPase (carrier) protein and represents complexation in the active site of the carrier and that the low-affinity site residues in the nonspecific acidic binding proteins. The contribution of Donnan equilibrium effects to the measured binding is shown to be insignificant. Stopped flow kinetic studies of Ca2+ passive binding with calcein and arsenazo III dyes have demonstrated that the binding to high-affinity site is very fast and that the overall binding reaction with the low-affinity site is slow, with a time course of about 4 s. Our analysis has shown that at least part of the low-affinity acidic proteins are within the SR matrix and that Ca2+ can reach them only by transversing the membrane via the Ca2+ carrier (Ca2+ ATPase). A model of the SR is proposed that accounts for several functional properties of the organelle in terms of its known protein composition and topological organization.


Structural changes and fluctuations of proteins. II. Analysis of the denaturation of globular proteins. The statistical thermodynamic model of protein structure proposed in paper I is developed with special attention to the hydrophobic interaction. Calorimetric measurements of the thermal denaturation of five globular proteins, ribonuclease A, lysozyme, alpha-chymotrypsin, cytochrome c, and myoglobin, are quantitatively analyzed using the model. The thermodynamic parameters obtained by the least squares method reflect the global, average properties of proteins and are in good agreement with the expected values estimated from experimental and theoretical studies for model peptides. The average bond energy epsilon is well related to the tertiary structure of each protein. However, the difference in the parameters between different proteins is not observed for the cooperative energy ZJ and the chain entropy alpha. The individuality of a protein as far as its structural stability is concerned, is mainly reflected by the parameter gamma specifying the hydrophobic nature of a protein. The model is further applied in the analysis of several aspects of the structural stability of globular proteins. Denaturation induced by denaturants, salts, and pH are also explained by the model in a unified manner.


Oligonucleotide conformations. (5) NMR and relaxation studies on GpU and UpG at neutral pH. The average conformation of GpU and UpG in neutral aqueous solutions has been investigated by proton chemical shifts and coupling measurements as well as T1 relaxation time experiments. The proportion of the N and S pseudorotational conformers of the ribose ring has been derived from the vicinal coupling constants. The relaxation data provide information about the syn--anti equilibrium of the orientation of the base about the glycosidic bond. This orientation is predominantly syn for the Guo base in both dinucleoside phosphates, that of Urd is anti in the case of GpU and shows an almost equivalent syn and anti character for UpG.


Kinetics of the polymerization reaction of tobacco mosaic virus protein: transient-saturation type polymerization reaction. The kinetics of the endothermic polymerization reaction of tobacco mosaic virus protein in the mild acid region was studied by means of temperature-jump (rising time of 6 sec)-turbidimetry, electron microscopy, and computer simulation. The time course profile of the turbidity increase changed from a normal one to an anomalous one as the size of the temperature-jump was made greater. The anomalous type polymerization profile, which we named the "transient-saturation" type, could be characterized by a rapid increase of turbidity and its transient saturation, and a slow increase to the final level. At a higher concentration of the protein, this transient-saturation effect was more marked, whereas the slow turbidity in the second phase occurred with a higher rate. This transient-saturation type polymerization profile was observed also in a pH-induced polymerization reaction. It was not observed in the case of the N-bromosuccinimide modified tobacco mosaic virus protein under a similar environmental change. By an electron microscopic study and computer simulation, it was revealed that in the first phase, a large number of short polymers were formed, and the concentration of the polymerizing units was rapidly reduced to the equilibrium value, and the polymerization reaction stopped transiently. In the second phase, polymer-polymer associations took place slowly and longer polymers were formed. The revlevance of the present study to the polymerization reaction of actin, myosin, and to a transient-overshoot type polymerization are discussed.


Our present knowledge of calcium or hydrogen ions as transmitters in the vertebrate rod outer segments. Difficulties in testing the possible role of calcium as a Transmitter in the R.O.S. are discussed. A comparison is made with the Sarcoplasmic Reticulum system where calcium flux are easily measured. The latest results reviewed on intact cellular structures are highly indicative but not yet conclusive.


Properties of intracellular ribonuclease utilized for RNA reduction in disintegrated cells of Saccharomyces cerevisiae. The properties of intracellular RNase in disintegrated cell suspensions of Saccharomyces cerevisiae have been studied. The influence of salt addition and/or incubation of the suspension on the activity of RNase and on the degradation of endogenous RNA was determined. No significant change in the RNase activity in the disintegrated suspensions was obtained by addition of 3% NaCl or by incubation at 50 degrees C with 3% NaCl. During the incubation with NaCl the active RNase was able to degrade endogenous RNA. By incubation without salt the RNase was inactivated. Inactivation also occurred after extraction at alkaline pH. The RNase had an optima at pH 5-6 and temperatures between 50-60 degrees C. The main part of the RNase in the unincubated suspension was soluble also at pH 4.0. No serious protein degradation occurred during the short time incubation needed for RNA reduction. 70% of the protein in the suspensions was recovered in the precipitate at pH 4.0 after 20 min of incubation. The corresponding protein recovery from unincubated suspensions was 77%.


Fermentation of glucose by Acetobacter melanogenus. Growing cultures of Acetobacter melanogenus ATCC 9937 concerted D-glucose to 2,5-diketo-D-gluconic acid with D-gluconic acid and 5-keto-D-gluconic acid as intermediates. The 2,5-diketo-D-gluconic acid was isolated from the fermented medium by treatment with an anion exchange resin.


Growth characteristics of Candida utilis on volatile substrate in a multistage tower fermentor. The influence of increasing ethanol concentration in the feed on growth and physiological activity of the yeast Candida utlis was studied. The measurements were made at steady states of continuous culture under constant values of dilution rate, temperature, and pH in all stages of the fermentor; Synthetic ethanol was used as the sole source of carbon and energy in the concentration range 10-100 g/liter. The maximum biomass concentration in the effluent and maximum productivity was achieved at 75 g ethanol/liter in the feed. In respect to ethanol losses in the outlet and biomass yield, the optimum ethanol concentration in the input of the growth medium was found to be about 50 g/liter using a four-stage system.


The enzymatic conversion of L-histidine to urocanic acid by whole cells of Micrococcus luteus immobilized on carbodiimide activated carboxymethylcellulose. Whole cells of Micrococcus luteus (formerly Sarcina lutea ATCC 9341) have been covalently linked to a carboxymethylcellulose support system, with the retention of histidine ammonia-lyase activity. The dependence of the rate of urocanic acid formation on pH, temperature, and added surfactant concentration was similar for the free and the immobilized cells. The immobilization procedure used is based on the carbodiimide activation of carboxymethylcellulose and has been optimized for the histidine ammonia-lyase activity of the immobilized cells on a given weight of cellulose. In a column reactor at 23 degrees C and superficial velocity of 0.044 cm/min, 5 g of cellulose with bound cells gave a 35% conversion of an L-histidine solution (0.25M, pH 9.0) to urocanic acid for 16 days of continuous operation. The scope of this carbodiimide assisted immobilization procedure has been investigated for a series of microorganisms and a variety of carboxylate functionalized supports.


Pepsin immobilized on inorganic supports for the continuous coagulation of skim milk. The milk-clotting enzyme pepsin was immobilized onto beads of alumina, titania, glass, stainless steel, iron oxide, and Teflon for treating skim milk in a fluidized-bed reactor. Two covalent attachment procedures using silanized supports and glutaraldehyde and two adsorption procedures were evaluated. The three best catalysts were titania and glass, using the covalent attachment procedure, and alumina, using the adsorption procedure at pH 1.2. The pepsin adsorbed on alumina catalyst has commercial potential compared to the previously used glass catalyst. Attempts to increase the stability of pepsin adsorbed on alumina by cross-linking with glutaraldehyde were unsuccessful owing to the low pH necessary for optimum pepsin adsorption; Desorption of pepsin from alumina during reactor operation was determined. Regeneration of spent catalysts was only partially successful.


[Effect of abrogating hybrid resistance on the survival of radiation chimeras]. A study was made of the effect of the hybrid resistance abrogation by means of the lymphoid cell administration on the survival of the lethally irradiated mice protected by the transplantation of the semiallogeneic bone marrow. Injection to the C57BLxCBA recipients of the C57BL lymphoid cells one day before the irradiation and the transplantation of the bone marrow of the same genotype (C57BL) increased the chimera survival in comparison with the untreated recipients; such pretreatment 7 days before the irradiation decreased the chimera survival. Parental spleen lymphocytes administration produced but an insignificant effect on the radioresistance both of the stem hemopoietic cells (by the endocolonisation test) and of the organism as a whole (by the 30-day survival test) of the F1 hybrid. On this basis a conclusion was drawn that the differences in the splenocyte efficacy, when they were injected at different periods before the irradiation, could not be attributed to the changes in radioresistance.


[Effect of 3-acetylpyridine on the functional activity of the adrenal cortex]. A reduction of blood corticosteroid content was observed in rats blood after the administration of 3-acetylpyridine. The rats given ACTH after 3-acetylpyridine showed a lesser elevation of corticosteroids in the blood and adrenal gland tissue than the intact animals; 3-acetylpyridine diminished the activity of dehydrogenase glucose-6-phosphate in the adrenal glands. The authors suggested that the action of acetylpyridine was realized at the adrenal gland level and consisted in inhibition of the NADP-H2 generation in the dehydrogenase systems.


[Participation of non-specific rat liver microsome oxidases in destruction of Nl-furanidylpyrimidines]. N1-(3'-Butyrolactono)-5-fluorouracil, N1-(2'-furanidyl) 5-trifluoromethyluracil, N1-(2'-furanidyl)-5-fluoracil are split in the rat organism with the formation of free 5-fluorouracil. The destruction of the C--N bonds in the molecule of the N1-(2'-furanidyl)-5-fluoracil takes place in the liver microsomes. This process is strengthened by NADPH and weakened by SKF-525A. All the three furanidylpyrimidines studied induced differential spectra of type I in the suspension of the liver microsomes. This fact testifies to the interaction of these substances with the cytochrome P-450.


[Immunocompetent lymphoi- cells from pregnant mice studied in the graft-versus-host reaction]. The capacity of lymphoid cells taken from C57BL/6 mice gravid from the CBA males (the second trimester) to induce the graft-versus-host reaction in the hybrids (CBA X C57B/6) F1 was reduced as compared with the cells of the virgin donors and syngeneic gravid mice. This was expressed by the prolonged survival of the experimental recipients and reduced inhibition of endogenous colony formation in the spleen of the sublethally irradiated (500 r) hybrids. At the end of gravidity this capacity was restored, in some instances even exceeding control figures.


[Development of the graft versus host reaction and its influence on pregnancy in mice following heparin administration]. The influence of heparin on the graft-versus-host reaction (GVHR) and the peculiarities attending the development of pregnancy in female animals which survived after the GVHR were studied. Preliminary administration of heparin to the recipients prevented their death or increased their life span. An intensification of the GVHR was noted after the administration of heparin to donors or its addition to the transplanted cells. In mice which survived after the GVHR as a result of heparin administration the intrauterine fetuses death and abortions were noted in 60-100% of cases during subsequent pregnancy (3 to 6 months after the cell transplantation). In the case of repeated pregnancies of these female animal pathology of pregnancy was less frequent; however, some of the offspring displayed the rant syndrome. No such disturbances of pregnancy were observed in mice given heparin alone or in those which survived after the transplantation of lymphoid cells only. The sustained pregnancy promoted the intensification of the GVHR induced in the female animals earlier after the heparin administration.


[Quantitative changes in gastric juice proteases in dogs during ulcer formation in the stomach]. Disc-electrophoretic investigation of proteases of the gastric juice of dogs under normal conditions and in experimental atophan ulcer of the stomach demonstrated that in fasting dogs ulceration was accompanied by marked quantitative changes in the protease spectrum. Fraction No. 6 showed a significant elevation against the background of total reduction of proteolytic fraction of the gastric juice in sham feeding of ulcerated dogs. Sham feeding replete ulcerated dogs indicated a marked increase of fractions No.1 and No.2. The noted changes of the gastric juice protease spectrum may be of ulcerogenic significance.


[Adrenergic component in the hepatotropic, carcinogenic effect of diethylnitrosamine]. The effect of norepinephine, an adrenomietic drug, and of pyrroxane, its antagonist, on diethylnitrosoamine (DENA) hepatocarcinogenesis was studied in albino rats. Norepinephrine was found to stimulate carcinogenesis, whereas pyrroxane--to inhibit this process; the latter drug decreased the incidence of multicentric tumours of the liver. In vitro experiments on the isolated rat atria showed low DENA concentrations (1x10(-6) to 1x10(-8) M) to sensitize the atrium adrenoreceptors to the endogenous and exogenous norepinephrine. A new hypothesis on the adrenergic component in the DENA carcinogenic effect caused by the endogenous norepinephrine is presented.


Current status of bone marrow transplantation for aplastic anemia and acute leukemia. Clinical results of marrow transplantation in the treatment of aplastic anemia and acute leukemia are reviewed. The principal problem areas in this field at this time are discussed.


Thrombin-induced vasodilation in the hindlimb (dog). The objective of this study is to test the hypothesis that the vasodilation produced by intra-arterial injection of thrombin to the hindlimb of a dog may be caused by the secondary release or production of some vasodilating substance. The vasodilator response to thrombin was compared with the vasodilator response to acetylcholine, isoproterenol, histamine and serotonin before and after blockade with atropine, propranolol, phenergan or methyl-D-lysergic acid butanolamide (UML-491), respectively. Though the appropriate blocking agent blocked the vasodilator response to the respective drug, the thrombin-induced vasodilation was not blocked. These data support the hypothesis that thrombin-induced vasodilation is a response to the thrombin moiety.


Anatomico-physiological considerations in exploration of the fourth ventricle. The advancement of surgical techniques has enabled the neurosurgeon to undertake a continually more aggressive approach toward lesions within the fourth ventricle. Laboratory and clinical observations have enabled us to conclude that (1) exploration of the fourth ventricle is feasible without anatomical disruption of the vermis, (2) controlled ventilation during such explorations is physiologically most desirable, and (3) irrigation of neural structures must consider acid-base and ionic parameters in order to maintain physiologic stability.


Uterine contractility.

Uterine contractility. Many factors appear to control uterine activity in the human, either by direct action or by modulating the effects of other agents. There is no evidence to conclude that any one substance is the pre-eminent controller of physiological activity. The final common mediator of contraction evoked by stimulants is calcium and without this contractility does not occur. The action of many relaxant and contracting drugs can be ascribed to their effects on calcium binding and intracellular availability.


Characterization of (+/-)-methadone uptake by rat lung. 1. By use of a sensitive and specific fluorescence assay procedure it was shown that after subcutaneous administration to rats, (+/-)-methadone was concentrated in the lung. Lung to serum ratios ranging from 25 to 60 were obtained indicating that the rat lung tissue was capable of extracting (+/-)-methadone against a concentration gradient. 2. This phenomenon was investigated in vitro with rat lung slices incubated in Krebs-Ringer phosphate buffer (pH 7.4). The uptake was expressed in terms of tissue to medium concentration ratios (T/M ratio). 3. The principal observations were: (i) Studies on the time-course of the uptake showed that the T/M ratios of (+/-)-methadone increased rapidly during the first 60 min of incubation and then more slowly, with a plateau occurring at 180 min; (ii) The T/M ratio of (+/-)-methadone progressively increased from 9.5 to 17 as the pH of the incubation medium was varied from 6.2 to 7.5; (iii) When the concentration of (+/-)-methadone in the incubation medium was varied from 0.005 to 0.5 mM, the T/M ratio decreased rapidly suggesting self-saturation of the transport process. Beyond the medium concentration of 0.5 mM, the T/M ratio declined very slowly. 4. These results suggested that at low concentrations, (+/-)-methadone was transported predominantly by a self-saturable process while at higher concentrations it was transported by a process of simple diffusion. 5. At low concentrations (0.01 mM) the uptake of (+)-methadone was higher than that of (-)-isomer indicating stereo-specificity of the uptake process. The uptake of (+/-)-methadone at low concentration (0.01 mM) was significantly inhibited by low temperature, lack of O2, lack of glucose, lack of Na+ in the incubation medium, and by exposure of the tissue to high temperature (approximately 100 degrees C). The uptake was also inhibited by relatively high concentration of iodoacetate (1.0 mM) and of naloxone (1.0 mM). 6. Kinetic analysis of data showed that the diffusion constant for (+/-)-methadone was 5.0 (h-1) and the Vmax of the active transport process was 6.5 micronmol g-1h-1.


The pharmacology of adrenergic neuronal responses in the cerebral cortex: evidence for excitatory alpha- and inhibitory beta-receptors. 1. The technique of microelectrophoresis was used to compare the actions of a range of adrenoceptor agonists on single cortical neurones in the rat anaesthetized with halothane. 2. Phenylephrine and methoxamine were exclusively excitatory, whereas salbutamol was entirely depressant. Noradrenaline and isoprenaline could evoke both excitatory and depressant responses. Lower doses of isoprenaline usually evoked depressions, whereas higher doses, on the same cell, evoked excitatory responses. 3. The alpha-adrenoceptor blocking agents, phentolamine and phenoxybenzamine, reversibly antagonized excitatory responses to adrenoceptor agonists, without affecting depressant responses to adrenoceptor agonists or excitatory responses to acetylcholine. 4. The beta-adrenoceptor blocking agents, propranolol and sotalol, reversibly antagonized both depressant and excitatory responses to adrenoceptor agonists, without affecting responses to acetylcholine. When the effect of sotalol on excitatory and depressant responses to adrenoceptor agonists was compared on the same cell, the depressant responses could be selectively antagonized, without affecting the excitatory responses. 5. It is concluded that (a) responses of cortical neurones to adrenoceptor agonists are mediated by both alpha- and beta-receptors; (b) these alpha- and beta-receptors give rise to opposite effects: the alpha-receptors being excitatory and the beta-receptors being inhibitory; and (c) responses of many neurones reflect the presence of both types of receptor.


The effects of labetalol (AH 5158) on adrenergic transmission in the cat spleen. 1. The competitive alpha- and beta-adrenoceptor blocking agent labetalol, in concentrations up to 10(-4) M, produced dose-dependent increases in transmitter overflow from the isolated blood perfused spleen of the cat following nerve stimulation at 10 and 30 Hz. 2. At concentrations above 10(-4) M labetol produced a pronounced decrease in transmitter overflow. 3. Labetalol (1.5 X 10(-4) M) increased the recovery of 3H label in the venous blood following the close-arterial infusion of [3H]-(-)-noradrenaline indicating that the drug inhibits uptake of the amine. 4. Both labetalol (3.8 X 10(-5) M) and piperoxan (7.4 X 10(-6) M) produced parallel shifts to the right of the dose-response curves to noradrenaline and oxymetazoline in isolated strips of cat splenic capsule. In this preparation both drugs acted as competitive postsynaptic alpha-adrenoceptor blocking agents. 5. Labetalol (3.3 X 10(-5) M) increased the transmitter overflow following stimulation of the splenic nerves with 200 impulses at 10 Hz. The overflow could be further increased by subsequent addition of piperoxan (7.2 X 10(-6 M). Piperoxan (5.7 X 10(-6) M) alone produced a marked increase in transmitter overflow which could be further increased by subsequent addition of desmethylimipramine (DMI; 3.2 X 10(-5) M). Cocaine (1.5 X 10(-5) M) or DMI (5.4 X 10(-5 M) produced a small increase in transmitter overflow which was not further increased by addition of labetalol (2.8 X 10(-5) M). 6. Labetalol produced a biphasic effect on the responses of the isolated blood perfused spleen of the cat to nerve stimulation. With low doses (up to 10(-4) M) vascular responses were potentiated and with high doses (greater than 10(-4) M) inhibited. The potentiation was related to uptake blockade and the inhibition to decreased transmitter overflow and postsynaptic alpha-adrenoceptor blockade. 7. Labetalol appears to act as a postsynaptic alpha-adrenoceptor antagonist in the isolated blood perfused spleen of the cat with little effect on presynaptic alpha-adrenoceptors. The moderate elevation of transmitter overflow by the drug is related to the inhibitory effect of the drug on neuronal uptake rather than on presynaptic alpha-adrenoceptors.


Drug prescription in Iceland.

Drug prescription in Iceland. Two ad hoc surveys on drugs prescribed in Reykjavik during November 1972 and November 1974 were made. After the first survey a publicity campaign was launched and doctors were encouraged to change their prescribing habits; only minor changes in docotors' prescribing habits were noticed, although it is realised that this type of programme will require a longer period to prove its effectiveness. The surveys showed that benzodiazepines are more widely prescribed than chlorodiazepoxide. Doctors have been warned of the probable addictive effect of benzodiazepines (Grimsson et al., 1974). Drug addicts who used to go from one surgery to another have now been identified and they can only receive drugs on prescription from their own family doctor or his deputy.


Glutamine synthetase. IX. Purification and characterization of the enzyme from sheep spleen. Glutamine synthetase (L-glutamate: ammonia ligase (ADP-forming), EC 6.3.1.2) has been purified about 550-fold from sheep spleen. The subunit weight of the enzyme is estimated to be 48 000. Sedimentation coefficient determination by density gradient centrifugation gives a value of 15.0 S. The approximate molecular weight calculated from the S value is 378500. In addition, electron micrographs of the enzyme show an "H" shape. Hence, the protein appears to have eight subunits. In sheep spleen, the enzyme resides chiefly in the soluble fraction of the cell. The amino acid composition of the enzyme from spleen shows similarity to that from other sources. The enzyme activity is nearly five times as high in Mg2+ as in Mn2+. ATP inhibits the enzyme; the inhibition is competitive with respect to Mg2+ATP. A number of compounds, such as D-alanine, AMP, creatine phosphate, arsenite in combination with 2,3-dimercaptopropanol, and 2-amino-4-phosphonobutyrate, also inhibit the enzyme. The inhibition by the last compound is competitive with respect to glutamate. D-Glutamate and alpha-methyl-DL-glutamate can serve as substrates in the synthesis reaction, but N-methyl-DL-glutamate cannot. On the other hand, neither D-glutamine nor N-acetyl-L-glutamine can replace L-glutamine as a substrate in the gamma-glutamyl transfer reaction of the enzyme. Inhibition of Mn2+ and ATP and its reversal by Mg2+ have been discussed as a means of regulating the enzyme activity in mammalian tissues.


Factors affecting inosinate synthesis and inosine triphosphate accumulation in human erythrocytes. Measurements of rates of inosinate synthesis from radioactive hypoxanthine by human erythrocytes show a large degree of individual variation. Rates of inosinate synthesis also vary with the pH and phosphate concentration of the incubation medium. This may be due to changes in the rate of phosphoribosyl pyrophosphate synthesis, and the stimulatory effect of phosphate on this process seems to be more important than the inhibitory effect of 2,3-diphodphoglycerate. The rate of inosinate synthesis, and especially the extent of accumulation of inosine triphosphate, increase disproportionately with time of incubation up to at least 24 h. Storage of erythrocytes also tends to increase inosinate synthesis and inosine triphosphate accumulation.


Synthesis of soluble dextran-hemoglobin complexes of different molecular sizes. Experimental conditions were defined that determined the synthesis of dextran-hemoglobin complexes through the alklation of hemoglobin by N-bromoacetylaminoethylaminodextran. Using appropriate concentrations of the two reactants, over 90% yield of dextran-hemoglobin was obtained for dextrans of average molecular weight of 200 000 110000, 70000, 400000, and 20000. Extensive viscosity increase due to crosslinking could be avoided, and a large molar excess of dextran over hemoglobin made unnecessary, under the optimal conditions.


The chemical and kinetic consequences of the modification of papain by N-bromosuccinimide. Nonactivated papain was treated with N-bromosuccinimide at pH 4.75. The N-bromosuccinimide-modified enzyme was characterized by (1) the change in absorbance at 280 nm, (2) amino acid analysis, (3) separate chemical determinations of tryptophan and tyrosine (4) difference spectroscopy, and (5) an N-terminal residue determination. It is concluded that N-bromosuccinimide in sevenfold molar excess oxidizes one tryptophan and two to three tyrosine residues per molecule of nonactivated papain, without causing peptide chain cleavage. Kinetic studies with several substrates and competitive peptide inhibitors were performed at pH6 using the N-bromosuccinimide-modified papain. In addition, the kinetics of the modified enzyme with the substrate alpha-N-benzoyl-L-arginine ethl ester were studied in the region of pH 3.5-9.0. All substrates (and inhibitors) test, with the exception of alpha-N-benzyoyl-L-arginine p-nitroanilide, displayed approximately a two fold decrease in both kcat and Km (or Ki), relative to the native enzyme. It is concluded that the key tryptophan residue which is probably Trp-177.


Purification and properties of dihydrofolate reductase from methotrexate-sensitive and methotrexate-resistant Chinese hamster ovary cells. We have previously described methotrexate-resistant Chinese hamster ovary cells which appear to contain normal levls of a structurally altered dihydrofolate reductase (EC 1.5.1.3) (Flintoff, W.F., Davidson, S.V., and Siminovitch, L. (1976) Somatic Cell Genet.2,245-261). By selecting for increased resistance form these class I cells, class III resistant cells were isolated which appeared to possess an increased activity of the altered enzyme. In the report, we describe the purification and several properties of the reductase from wild-type cells, two independently selected class I cells, and class III resistant cell. The reductases from wild-type and resistant cells had similar specific activities using folate and dihydrofolate as substrates, and similar molecular weights as determined by sodium dodecyl sulfate gel electrophoresis. The mutant enzymes, however, were about six- to eight-fold more resistant to inhibition by methotrexate than the wild-type enzyme, suggesting a decreased affinity of the mutant reductases to methotrexate-binding. Small differences between various enzymes were also seen in other physicochemical properties such as pH optima and Km values for folate, and in their heat stabilities, which suggest that different structural alterations may lead to the same mutant phenotype. As expected from earlier studies with crude extracts, class III cells did produce a higher (about 10-fold) yield of the reductase than the class I or wild-type cells.


Reversibility of the ampicillin-and nitrite-induced inactivation of beta-lactamase I. beta-Lactamase I was isolated from Bacillus cereus 569/H. Treatment with ampicillin in the presence of sodium nitrite at pH 4 or 5 resulted in the inactivation of the enzyme presumably by modification of a carboxyl group in the active site. However, this inactivation was rapidly, reversible at neutral pH and the available evidence points to the participation of a second carboxyl group which is involved in the reactivation process.


The interactions between cytochrome c and cytochrome oxidase that determine the conformation of the oxidized oxidase. 1. Cytochrome c2+ increases the rate at which cytochrome oxidase (EC 1.9.3.1) gamma max428nm) converts to its conformational isomer (gamma max 418-423 nm) but cytochrome c3+ has little effect on the conversion rate. 2. Interactions between reduced cytochrome oxidase and cytochrome c were studied in the absence of electron flow using anaerobic Sephadex columns. 3. Oxidase that is reduced by cytochrome c2+ or other reductant forms the 418-to 423-nm isomer if its last contact, before oxidation, is with cytochrome c3+. If the reduced oxidase contacts cytochrome c2+, before oxidation, the 428-nm oxidase forms.


Mechanism of action of Zn2+ and Mg2+ on rat placenta alkaline phosphatase. II. Studies on membrane-bound phosphatase in tissue sections and in whole placenta. Alkaline phosphatase (EC 3.1.3.1) bound to trophoblastic cells in rat placenta is activated by Mg2+ and inhibited by Zn2+ in the same way as is found with partially purified soluble alkaline phosphatase in the same tissue (PetitClerc, C., Delisle, M., Martel, M., Fecteau, C. & Brière, N. (1975) Can. J. Biochem. 53, 1089-1100). In studies done with tissue sections (6-10 micron), it is shown that alkaline phosphatase activity and labelling of active sites by orthophosphate are lost during incubation with ethanolamine at pH 9.0. Addition of Mg2+ causes total recovery of catalytic activity and active sites labelling. Zn2+ displaces and replaces at the Mg2+ binding sites. The affinity for both ions is similar, and dissociation of Zn2+ from the enzyme is a very slow process, even in the presence of Mg2+. The Zn2+-alkaline phosphatase and Mg2+-alkaline phosphatase, which only differ by the ion bound to an apparent modulator site, have the same catalytic activity at pH less than 7.0, but the Zn2+ species has little activity at alkaline pH. Phosphorylation of the enzyme by orthophosphate indicates that with both enzyme species phosphoryl intermediate does not accumulate at alkaline pH. These results suggest that with orthophosphate, the phosphorylation step is rate determining for both enzymes, and that Zn2+ affects this step to a much greater extent. It is proposed that Zn2+ and Mg2+ regulate alkaline phosphatase in rat placenta. The concentration of both ions in maternal serum and placenta suggest that such a mechanism could exist in vivo.


The subcellular distribution of poly-A-degrading activity in mouse kidney. Most (95%) of the poly-A-degrading activity of the mouse kidney was found in the cytoplasmic fraction and only 5% was found in the nuclear fraction; 43% of the poly-A-degrading activity of the cytoplasm was found in the mitochondria, 22% in the microsomes, and 30% in the soluble fraction. Differences in activity and specificity indicate that poly A is degraded in the nucleus by enzymes that are separate and distinct from the enzymes in the cytoplasm that degrade poly A. The nuclear poly-A-degrading activity can be separated into an endonuclease with a general specificity and exonuclease, similar to one found in Ehrlich ascites tumor cells, which shows some specificity for poly A.


The effects of light and tyrosinase during sclerotium development in Sclerotium rolfsii Sacc. Some effects of light on morphogenesis in Sclerotium rolfsii Sacc. were studied. Physiological competence to visible light developed during the first 120 h after inoculation, with an optimum sensitivity phase between 84 and 96 h that coincided with the leading hyphae reaching the edge of the Petri dish. Although sclerotial initials were produced in dark-grown cultures, light was necessary for the continuation of the developmental and maturation phases of sclerotial morphogenesis. Tyrosinase activity (o-diphenol: oxygen oxidoreductase, EC 1.10.3.1) was detected during sclerotial formation and the pH and temperature optima for his polyphenol oxidase in vitro were about 6.0 and 45 degrees C respectively. The enzyme was inhibited by cysteine. Similar activity levels of tyrosinase were obtained in blue and "white" light-grown cultures but in red light activity was comparable with that of dark-grown cultures. Laccase activity was not detected at any stage of development.


Stannous and cuprous ion oxidation by Thiobacillus ferrooxidans. Oxidation of stannous chloride by Thiobacillus ferrooxidans was studied manometrically. At low stannous ion concentrations, initial oxidation rate was proportional to concentration. Optimum pH for oxidation was 2.3 optimum temperature was 37-40 degrees C. Spectrophotometry showed reduction of cytochromes in suspensions of whole cells on addition of ferrous, stannous, or cuprous salts. Cytochrome c reductase activity in cell-free extracts was assayed with ferrous, stannous, or cuprous ions as electron donors. It appears unlikely that an essential non-biological reaction, the reduction of ferric ions by stannous or cuprous ions, is involved. Growth of T. ferrooxidans was not obtained with either stannous chloride or stannous sulphate as sole energy source.


Prolactin binding in ovariectomy-responsive and ovariectomy-nonresponsive rat mammary carcinoma. Growth of the transplantable mammary tumor, MTW9, in W/Fu rats is greatly enhanced by elevated serum prolactin concentrations. This report compares the prolactin binding to tumor membranes in two mammary tumor strains derived from MTW9. Maximum binding to membranes of both tumors occurred at pH 7.6 after incubation for 30 hr at 4 degrees. The binding was inhibited only by polypeptide hormones that possess lactogenic activity. MTW9-P, an ovariectomy-responsive tumor developed in rats maintained on daily perphenazine injections, had 4-fold-higher prolactin binding than had MTW9MtT, an ovariectomy-nonresponsive tumor developed in rats bearing the mammosomatotropic pituitary tumor, MtTW10. Withdrawal of perphenazine from rats bearing MTW9-P caused a fall to normal of plasma prolactin, no tumor regression, and no significant change in prolactin binding. In contrast, resection of MtT resulted in tumor regression, a fall to normal of serum prolactin, and a nearly 3-fold increase in prolactin binding. Scatchard plots of prolactin binding data yield an apparent affinity constant, Ka, of 1.2 X 109 liters/mole for both tumors. The 4-fold-higher prolactin binding in the ovariectomy responsive variant suggests a positive correlation between ovariectomy response and the number of membrane prolactin-binding sites. No correlation between prolactin sensitivity and prolacting binding is apparent.


Transglutaminase activity in normal and transformed cells. Transglutaminase activity was determined in normal and transformed paired cell systems. Reduced enzyme activity was found in virus-transformed human and hamster cells and in chemically transformed mouse cells relative to normal counterparts. Most of the enzyme activity was localized in the particulate fraction sedimenting at 105,000 X g. Enzyme activity was highest when normal cell populations were in an essentially nonmitotic state. Protein capable of incorporating putrescine was present in normal and transformed human cells, although the rate of incorporation was lower in the latter. The putrescine acceptor in the normal cell paralleled enzyme activity and enzyme distribution. Trypsin (5 microng/ml) treatment of the normal cell resulted in a 3-fold increase in enzyme activity, which occurred independently of protein synthesis.


Interactions between "fever" proteins and normal serum proteins in febrile cancer patients. When analyzed by cationic discontinuous electrophoresis in urea-containing polyacrylamide gels, plasma or serum from febrile individuals contains trace quanitites of five protein bands that are not recognizable in the blood of normal individuals. These proteins appear and disappear in parallel in sequential samples. Cerebrospinal fluid from febrile and nonfebrile individuals contains a protein band that is electrophoretically identical with only one of these proteins. Since the trace proteins migrate, in urea-containing polyacrylamide gel electrophoresis, as if they has molecular size of less than or equal to30,000 daltons, their absence from cerebrospinal fluid implies the existence, in vivo, of interactions between them and other serum proteins. Under nondissociating conditions, four of the bands appear to circulate in physical interaction with one another. In molecular sieve chromatography at neutral pH in lipid-free sera, the trace proteins have an approximate molecular size of 165,000 daltons; in lipemic sera they have a molecular weight of larger than or equal to200,000 daltons. Their behavior in gel filtration and in ion-exchange chromatography excludes extensive interaction with any of the following: immunoglobulin M, immunoglobulin G, alpha2-macroglobulin, haptoglobin, and albumin. Interactions between these and other serum proteins are reduced by high concentrations of urea and by low PH. The mechanisms responsible for the observed protein-protein associations would appear to include electrostatic attraction, hydrogen bonding, and weak hydrophobic interaction.


Adrenergic, cholinergic, and inactive human neuroblastoma cell lines with the action-potential Na+ ionophore. Cultured human neuroblastoma cell lines were assayed for biochemical characteristics of neuonal function. Cell lines studied included LA-N-1, LA-N-2, IMR-32, SK-N-SH, and SK-N-MC. Veratridine-dependent uptake of 22Na+ implied the presence of the action potential Na+ ionophore in LA-N-1, LA-N-2, IMR-32, and SK-N-SH. The time course of 22Na+ uptake and inhibition of uptake by tetrodotoxin supported this. SK-N-MC had no veratridine-dependent 22Na+ uptake. Tyrosine hydroxylase (EC 1.14.10.), glutamic acid decarboxylase (EC 4.1.1.15), and acetylcholine contents in neuroblastoma cells were compared to those in brain. LA-N-1 and IMR-32 contained 15 and 5 times as much tyrosine hydroxylase, respectively, whereas LA-N-2, SK-N-SH, and SK-N-MC contained only 0.5 to 5% of that in brain. Acetylcholine was present in -LA-N-2 in 15- to 20-fold greater quantities than in brain; other lines had only 10 to 50% of that in brain. None of the cell lines contained glutamic acid decarboxylase. Thus, continuously propogated human neuroblastoma cell lines may have the action potential Na+ ionophore and may be adrenergic (LA-N-1 and IMR-32), cholinergic (LA-N-2), or inactive (SK-N-SH and SK-N-MC). This is the first demonstration of the action potential Na+ ionophore and of acetylcholine production in human neuroblastoma cell lines.


Effects of graft-versus-host reaction on inhibition of tumor growth in vivo and on tumor cytotoxicity in vitro. In DA X Wistar F1 rats, growth of 10(4) Wistar-specific Sp 1 carcinoma cells s.c. was commonly prevented by a mild subclinical graft=versus-host reaction produced by injecting 50 X 10(6) Wistar spleen cells i.p. either concurrently with the tumor or 7 to 14 days previously, Spleen cells alone had no effect on established tumor, but their injection on Day 14 significantly reduced the recurrence rate after excision of tumor on Day 21. In vitro tests in tumor-bearing rats with graft-versus-host reactions showed increased spleen lymphocyte and serum cytotoxicity; these mechanisms may inhibit tumor growth in vivo. Because Wistar lymphocytes and Sp 1 cells are syngeneic, inhibition of tumor cannot be due to allograft rejection but is probably an effect of increased host immunoreactivity during the graft-versus-host reaction.


Reactions of cellulose isothiocyanates with thiol and amino compounds. A cellulose isothiocyanate has been prepared by treatment of cellulose with 2,4-di-isocyanatotoluene followed by hydrolysis and reaction of the resulting amine with thiophosgene. The cellulose isothiocyanate was characterized by its binding capacity with respect to [14C]-glycine, [131 I]-human serum albumin, and 2-mercaptoethanol. An analytical method for binding capacity, based on reaction with [35 S]-alpha-toluenethiol, was developed. Because of the aromatic character of the NCS group of the cellulose isothiocyanate, the covalently bonded thiol can be quantitatively liberated.


Proliferation of erythroid and granulocyte progenitors in the spleen as a function of stem cell dose. A study of the kinetics of cellular proliferation, in the morphologically unrecongizable haemopoietic progenitor cell compartment, as a function of injected CFU-S dose has been carried out in the spleens of lethally X-irradiated mice using 3H-TdR labelling. Amplification in this proliferating cell compartment was observed to decline as CFU-S dose increased. The number of divisions in the differentiated line arising from CFU-S up to the first appearance of recognizable erythroid precursors were calculated to be 9-2, 12-5, 15 and 17 for the 2, 0-35, 0-05 and 0-007 femur equivalent doses respectively. The growth of cell populations arising from CFU-S was biphasic, with a rapid initial phase having a doubling time of about 6-3 hr, and a slow phase of doubling time around 1 day. Analysis of the rapid phase by the FLM method gave a cycle time of 5-6 hr, Recognizable labelled erythroid precursors were detected at the same time as, or just after, the change in slope of the growth curve. Significant numbers of proliferating (labelled) granulocytes only appeared in the spleens of animals receiving the higher marrow doses (2 and 0-35 femur). The erythroid to granulocyte ratio was also a decreasing function of marrow dose.


The form and function of cnidarian spirocysts. 3. Ultrastructure of the thread and the function of spirocysts. Unlike most nematocysts, undischarged spirocyst threads bear hollow tubules rather than spines. The undischarged tubules are interconnected in hexagonal arrays and appear to be arranged in bundles along the length of the thread. Although the wall of the thread is folded in length and width, the tubules are not. Upon discharge and contact with sea water, the tubules solubilize and adhere to various substrates and prey. Traction between such objects and the everting thread causes the tubules to spin out into a web or meshwork of fine microfibrillae. Lack of contact of the everting thread with objects results in the tubules forming small droplets of partially solubilized material, some of which appear to be arranged in a helical pattern around the thread. The web or meshwork formed by the solubilized tubules in contact with various substrates probably serves to increase significantly the surface area and adhesive properties of the everted spirocyst thread.


Importance of glycerol and fatty acid residues on the ionic properties of phosphatidylglycerols at the air-water interface. Ionic properties of didodecanoylphosphatidylglycerol (C12PG), didodecanolyphosphatidyl-l'-propanol (C12PP), di-(12-methyl, 13-methyl)-pentadecanoylphosphatidylglycerols (C15PG) and dihexadecanoylphosphatidylglycerol (C16PG) have been studied at the air-water interface using titration experiments at constant ionic strength and film expansion experiments at constant pH, with Li+, Na+, K+ and Cs+ in the subphase. For each lipid, the apparent pK in the surface is strongly dependent on the subphase salt concentration and differs from expected intrinsic pK in the bulk. Discrimination between alkaline cations is observed. These results can be accounted for by strong surface potentials, which are satisfactorily calculated by using the Gouy and Chapman theory of the diffuse double layer. The comparison of C12PP and PG expansion data shows the importance of the glycerol residue of PG ionic properties, favouring penetration of cations in the films. Lipids in the liquid-crystalline state, such as C12-and C15PG, do not interact with alkaline cations as does C16PG in the gel phase. In particular, film condensations bring about a clear-cut discrimination between Na+ and K+. Results are discussed with regard to cation penetration and the structure of water at the interface. The importance on membrane functions of these strong surface potentials generated by PG monolayers is suggested.


[Increase in the oxygen available to the cerebral cortex after the administration of carbonic anhydrase inhibitors]. Oxygen tension (pO2) in cerebral cortex was measured by polarographic method in unanesthetized rabbits. Intravenous administration (25 mg/kg) of carbonic anhydrase inhibitors (acetazolamide, methazolamide, dichlorphenamide, sulthiame) induced an early important rise of cortical p O2, which is not dependent on increase of p O2 and p CO2 and decrease of pH in arterial blood. High dosage of acetazolamide (250 mg/kg) produced the same effect and did not suppress the increase of cortical p O2 under air-CO2 inhalation. This result suggests that CO2 might act specifically upon cerebral vessels.


An extrarenal source of "renin-like" activity in anephric man. To examine extrarenal sources of "renin-like" activity plasma was obtained from 19 anephric males. Plasma renin activity (PRA), concentration (PRC) (obtained after addition of exogenous renin substrate) and total renin concentration (TRC) (obtained after acid-activation of plasma and subsequent incubation with exogenous renin substrate) demonstrated values for several anephric patients comparable or above those seen in plasma from 10 normal subjects. Incubation of untreated plasma (PRA and PRC) and acid-dialyzed plasma (TRC) for angiotensin I generation was performed at pH 7.5, at 37 degrees C with EDTA, dimercaprol, and 8-OH-quinoline as angiotensinase and converting enzyme inhibitors. The pH optimum for acid-activation of TRC in anephric plasma was the same as that in normal plasma (pH 3.3). Molecular weight determinations following Sephadex gel chromatography demonstrated that the renin-like enzyme in normal plasma had a molecular weight of about 42,000 before and after acid-activation, while that in anephric plasma had a molecular weight of approximately 61,000. A saliva sample from one anephric subject with the highest levels of PRA, PRC, and TRC in plasma also demonstrated measurable amounts of PRA, PRC, and TRC. The molecular weight of this salivary "renin-like" activity also was 61,000. These observations suggest a possible extrarenal source of "renin-like" activity in anephric man. The physiological significance of these studies remains to be clarified.


An inactive renin in human plasma.

An inactive renin in human plasma. Normal human plasma contains an active form of renin that is activated by acidification to pH 3.0 and comprises 56% of the total renin. In our study, inactive renin was also present in plasma from five anephric persons, and the proportion of active to inactive renin in these subjects was similar to normal. Plasma from normal pregnant women contained increased concentrations of inactive renin and the proportion of inactive renin was raised to around 66%. Plasma from persons with renal hypertension contained varying amounts of inactive renin but the mean percentage (35%) was lower than normal. An infusion of saralasin sufficient to lower the blood pressure in five subjects with renal hypertension resulted in a rise in active renin concentration but no change in the concentration of inactive renin. Plasma angiotensin II correlated with active renin but not with inactive renin, suggesting that the inactive renin does not produce angiotensin II in vivo.


Effect of beta-blocking agents and angiotensin II on isoproterenol-stimulated renin release from rat kidney slices. Mechanisms by which beta-blocking agents decrease blood pressure and suppress renin release are incompletely understood. We previously demonstrated that renin release by kidney slices may be increased by beta-adrenergic agonists, and the present communication contains our results on the effects of 15 beta-blocking agents and angiotensin II on isoproterenol-stimulated renin release. None of the beta-blocking compounds inhibited basal renin release. Each agent was evaluated at concentrations ranging from 10-8 to 10-5 m and three different dose-response curve patterns were observed: (1) Metoprolol, acebutolol, labetalol, and d-propranolol had no effect on isoproterenol-stimulated renin release at any concentration, whereas pindolol and bufuralol demonstrated minimal inhibition at 10-5 m only. (2) Isoproterenol stimulation was completely inhibited when dl- or l-propranolol, alprenolol, and sotalol were administered at doses ranging between 5 x 10-6 and 10-6 m; but greater concentration of these agents resulted in reappearance of the isoproterenol response. (3) Dose-related inhibition was observed with practolol, oxprenolol, timolol, nadolol, and atenolol at concentrations ranging from 10-8 to 10-5 m. Basal renin release was significantly (P is less than 0.01) inhibited by angiotensin II at 10-6 m, which also inhibited isoproterenol-stimulated renin release in a dose-related fashion. [Sar1, Ala8] angiotensin II had no direct effects on either basal or isoproterenol-stimulated renin release, but blocked the inhibitory action of angiotensin II on these parameters. There are three different effects of beta-blocking agents on isoproterenol-stimulated renin release which can only partially be explained by their presently ascribed pharmacological properties. (Beta 1- and beta2-agonists, intrinsic sympathomimetic activity, membrane-stabilizing actions). Angiotensin II inhibition of renin release appears to be functionally related to adrenergic pathways.


alpha-Adrenergic reduction of cyclic adenosine monophosphate concentrations in rat myocardium. We determined the effect of alpha-adrenergic receptor stimulation on cyclic adenosine monophosphate (cyclic AMP) concentrations in isolated myocytes derived from adult rat hearts and in isolated perfused rat hearts. Activation of alpha-adrenergic receptors with either phenylephrine (10(-8) M to 10(-6) M) or epinephrine (10(-8) M to 10(-6) M) plus propranolol (10(-6) M) resulted in a reduction in cyclic AMP levels in isolated myocytes. The action of phenylephrine was antagonized by phentolamine (10(-6) M). Phenylephrine (10(-5)M attenuated cyclic AMP generation in response to isoproterenol (10(-8) M and 10(-5) M). However, this effect of phenylephrine was not antagonized by phentolamine. Elevation of cyclic AMP concentrations produced by glucagon and by theophylline in isolated myocytes was attenuated by phenylephrine and by epinephrine plus propranolol and the attenuation was antagonized by phentolamine. In isolated perfused rat hearts epinephrine (10(-6) M), when given with propranolol, diminished the rate of development of tension and also reduced tissue levels of cyclic AMP. Epinephrine alone, as well as isoproterenol, increased contractility and myocardial cyclic AMP concentrations as expected. These results indicate that catecholamines may increase or decrease cyclic AMP levels in rat myocardium, depending on the intensity of stimulation of receptor types. Increases are mediated by beta-adrenergic receptors, whereas decreases appear to by mediated by alpha-adrenergic receptors.


Detection of errors in methylmalonyl-CoA metabolism by using amniotic fluid. We report a method for rapid prenatal detection of methylmalonic acidemia, consisting of measuring methylmalonly-CoA mutase (EC 5.4.99.2) activity in non-cultured amniotic cells and measuring the concentration of methylmalonate in the amniotic fluid. Immediate stabilization of the mutase activity in the non-cultured amniotic cell by its coenzyme adenosycobalamin, and use of methylmalonyl-CoA with high specific activity gives mutase activity comparable to that of cultured amniotic cells or normal fibroblasts. Consequently, findings of low mutase activity and a hight concentration of methylmalonate in the amniotic fluid allows accurate diagnosis of the vitamin B12-nonresponsive form of methylmalonic acidemia. These results can be obtained in two days. For the vitamin B12-responsive form, the correct diagnosis depends upon finding amniotic fluid methylmalonate, because cells from these patients will display normal methylmalony-CoA mutase activity after adenosylcobalamin is added. Problems in interpreting data on bloody samples and the limitations of the method are discussed.


The effects of ethanol (0.75 g/kg body weight) on the activities of selected enzymes in sera of healthy young adults: 1. Intermediate-term effects. We report the intermediate-term effects of three consecutive evenings of moderate ethanol ingestion (0.75 g/kg body weight each evening) on activity values for alkaline phosphatase, gamma-glutamyltransferase, creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in sera of nine apparently healthy young adults. We define "intermediate-term" effects as those occurring between 10 h and 100 h after completion of the ethanol consumption schedule. The most pronounced changes in enzyme activity for the group of volunteers were: gamma-glutamyltransferase, +25% at 60 h after ethanol ingestion; alanine aminotransferase, +12% at 60 h after ethanol; and aspartate aminotransferase,--12% at 60 h after ethanol. All three enzymes exhibited similar time courses, i.e., mean peak activity changes were observed at 60 h, and all three mean enzyme activity values returned to near baseline by 100 h. The possible explanations for the observed changes and the clinical significance are discussed.


New substrate for fluorometric determination of gamma-glutamyltransferase activity in serum. We describe the preparation of a new substrate, N-gamma-L-glutamyl-5-aminoisophthalic acid dimethyl ester hydro-chloride, for the fluorometric determination of gamma-glutamyltransferase activity in serum by the "front-surface" technique. Details of the resulting method are provided. The final reaction mixture contains 4 mmol of the substrate per liter of tris(hydroxymethyl)aminomethane (100 mmol/liter) and glycylglycine (75 mmol/liter) at pH 8.2 (25 degrees C).


Gamma-glutamyltransferase activity in plasma: statistical distributions, individual variations, and reference intervals. Measurement of gamma-glutamyltransferase activity in plasma provides a useful index to liver function. Using as our study population those persons coming to the Center for Preventive Medicine, we described and measured the significance and importance of physiological and environmental variations. We established a classification for the variation factors. The three most important factors affecting this activity were drug intake, alcohol consumption, and excessive weight, followed by sex and age. We suggest a preliminary group of reference intervals for healthy subjects to be used in interpreting a laboratory test.


Vitamin B12 radioassay with oyster toadfish (Opsanus tau) serum as binder. We describe a vitamin B12 radioassay in which oyster toadfish (Opsanus tau) serum is used as the binding protein. The serum is quite stable and has a high capacity and high binding affinity (K greater than 10(12) liter/mol) for vitamin B12. The binding is not significantly affected by temperature, the presence of denatured proteins, or the amount of vitamin B12 present. The radioassay is reproducible (CV 4.4%) within assay, 7.8% between assays) and sensitive (12 ng/liter). Assay accuracy is unaffected by the protein in serum or by reasonable variations in incubation temperature and time.


Canaline carbamoyltransferase in human liver as part of a metabolic cycle in which guanidino compounds are formed. This and previous papers examine the reasons for the relationship between the concentrations of guanidino-succinate and guanidinoacetate in human urine. With the demonstration here that extracts of human liver-tissue can mediate ureidohomoserine formation from canaline [(2-amino-4-aminooxy)-butyric acid] and carbamoyl phosphate, all steps in a cycle proposed for the production of guanidinoacetate and guanidinosuccinate have been documented. This includes synthesis of canavaninosuccinate from aspartate and ureidohomoserine, reductive cleavage of canavaninosuccinate to form guanidinosuccinate and homoserine, or, alternatively, lytic action on canavaninosuccinate to form fumarate and canavanine, and transamidination to glycine to form guanidinoacetate, regenerating the canaline. We propose that canaline originates from aspartate, but the precise mechanism by which canaline is formed needs to be elucidated.


Diurnal variations of urinary enzyme excretion. Variations in the urinary excretion of arylsulphatase A, beta-galactosidase, alpha-glucosidase and beta-glucuronidase throughout a 24-h period were studied in 8 healthy subjects. Urine was collected at 3-h intervals and enzyme activities were assayed after gelfiltration of the urine specimens. Significant intra-individual changes of the excretion of all 4 enzymes during the 24-h period were found. Enzyme output was high between 3 a.m. and 9 a.m. and low during the afternoon and evening hours. The most striking pattern was seen for arylsulphatase A. Diurnal variations of urinary enzyme excretion seemed not to be flow dependent. Both modes of expression of enzyme output (mU/min or U/g creatinine) gave corresponding results. It is concluded that for the measurement of the excretion of these enzymes urine should be collected during a fixed time interval, e.g. from 6 a.m. to 9 a.m.


Properties of amylase-linked immunoglobulins. In this report, the properties of eight cases of amylase-linked immunoglobulins were gel filtration using Sephadex G-200 superfine. The class of heavy chain of amylase-linked immunoglobulins was proved to be gamma in four cases and alpha in three cases by immunoelectrophoresis followed by amylase activity staining. In one of the cases, the precipitin line against light chain lambda could be visualized only after treatment with 0.1 M 2-mercaptoethanol. Then, the type of light chain was determined to be exclusively lambda irrespective of heavy chain classes. In two cases, the immunoglobulin complexes were partially dissociated into normal amylase and immunoglobulin G at pH 8.6, and completely dissociated at pH 9.0. In three cases, the complexes were completely dissociated at pH 8.6. The precipitin line of papain treated amylase-linked immunoglobulin G against anti-Fc was not. This fact suggests that the binding site of amylase-linked immunoglobulins G was located in the Fab portion of immunoglobulin molecule and that the complexes are specific antigen-antibody complexes. Treatment with Con-A Sepharose caused the dissociation of the amylase-immunoglobulin complexes. It is suggested that the changes in the conformation of amylase-linked immunoglobulin causes the dissociation of this immuno-complex. Thus, it is elucidated that the complexes of amylase and immunoglobulins are specific antigen-antibody complexes, and that these complexes must be recognized as one of the circulating autoantibodies in plasma, and must be clearly distinguished from the other unknown macromolecular amylase complexes.


Determination of total carbon dioxide in serum and plasma using a carbonate ion-selective membrane electrode. A new manual method for the determination of carbon dioxide content in serum and plasma, based on the potentiometric measurement of carbonate, is proposed and evaluated. The new method offers good precision and accuracy in the physiological concentration range as shown by detailed studies on synthetic samples, reference standards, and actual patient samples. Moreover, the method yields results which correlate very well with analyses carried out using various conventional techniques. It is expected that the proposed method could be used for manual determinations of CO2 content, especially where rapid start-up time, minimal sample treatment, and low cost are of importance.


Clotting in dialyzers due to low pH of dialysis fluid. During November and December 1975 frequent clotting occurred in the extracorporeal circuits of different dialyzers used in our unit. After installation of new automatically regenerating ion exchange resin columns,, the pH of deionized water ranged from 4.2 to 8.4 during 24 hr periods. Dialysate pH ranged between 5.3 and 8.2, and the patient's whole blood pHs ranged from 7.15 to 7.4 at the dialyzer inlet and from 6.2 (!) to 7.4 at the outlet. A strong correlation was seen between the acidity of the water and the frequency of clotting, and it was considered possible that the clotting was due to structural changes within the heparin molecules induced by the low pH. Following the introduction of an automatic titration device into our dialyzate preparation system, clotting with consecutive blood loss and subjective clinical symptoms have disappeared.


Influence of intrinsic sympathomimetic activity and cardioselectivity on beta adrenoceptor blockade. Dose-response curves for propranolol and oxprenolol were studied in healthy volunteers, with a standardized excercise test and percentage reduction in excercise heart rate (EHR) as the index of drug effect. The dose-response curves obtained were compared with similar curves previously reported for sotalol, practolol, and atenolol with identical experimental methods. Two distinct types of response were identified: in the first, shown by propranolol and sotalol, increasing doses of the beta adrenoceptor-blocking drug continued to produce increasing effects to the limits of the dose levels examined; with the second (oxprenolol and practolol), increasing the dose initially resulted in substantial increase in effect but subsequently larger doses produced almost no increase in effect. Consideration of the additional properties of these beta adrenoceptor-blocking drugs revealed that both practolol and oxprenolol have intrinsic sympathomimetric activity (ISA), whereas propranolol and sotalol do not. In addition, practolol is cardioselective. Further investigation of the possible influence of ISA or cardioselectivity on beta adrenoceptor-blocking activity was undertaken by studying the effects of combinations of drugs on EHR. Sotalol produced greater effect when given 2 hr after sotalol, oxprenolol, practolol, or atenolol. When oxprenolol was given after sotalol or oxprenolol, or practolol was given after sotalol or practolol, there was no further increase in percentage reduction in EHR. When atenolol was given, the combinations of sotalol and atenolol together with two doses either of sotalol or atenolol all induced increases and similar final percentage reductions in EHR. Thus atenolol induces effects like those of sotalol, which are quite different from those of oxprenolol or practolol. The presence or absence of ISA would appear to be the important difference between these two groups of drugs: ISA would, therefore, appear to be demonstrated in man by flattening of the dose-response curves with exercise.


The physiologic treatment of nasal obstruction. Although criticisms of the submucous resection of the nasal septum and turbinectomy have been given, this is not to discredit these procedures when they are truly indicated. Certainly there are anatomic deformities causing nasal obstruction wherein a submucous resection of the septum or a submucous resection of the anterior portion of the inferior turbinate would be of benefit. The surgeon performing rhinoplastic surgery must be aware of the physiologic causes of nasal obstruction. Often a combination of structural deformity and rhinitis is blocking the airway. Intranasal, intramucosal injections of long acting corticosteroids have proven to be of great benefit in the treatment of chronic allergic, vasomotor, and hypertrophic rhinitis, and they are a useful adjunct to rhinoplastic surgery.


Valsalva vasoconstrictor reflex in human hypertension in after beta-adrenoreceptor blockade in conscious rabbits. 1. A Valsalva-like manoeuvre was used to elicit graded rises in total peripheral resistance (TPR) in conscious rabbits. The rises were reflex and mediated through sympathetic constrictors. Propranolol infused at different rates reaching plasma concentrations up to 240 (SEM 33) ng/ml had no effect on this reflex but reduced mean arterial pressure. However, the response was attenuated by clonidine in a dose-dependent manner. 2. Valsalva manoeuvres were used to elicit graded sympathetically mediated rises in TPR index in twenty-nine subjects with mean arterial pressure ranging from 75 to 165 mmHg. Absolute sensitivity of the constrictor response increased with rising resting TPR index, resulting in some enhancement of constrictor responses in the hypertensive subjects. It seems likely that non-autonomic factors (e.g. vessel structure) rather than hyperactive neural constrictor effects are involved in the enhanced constrictor responses in essential hypertension.


Peripheral and central catecholaminergic neurons in genetic and experimental hypertension in rats. 1. Activity of peripheral and central catecholaminergic neurons was studied in spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats. 2. In young SHR (4 weeks) the plasma values of bpth noradrenaline and dopamine-beta-hydroxylase activity were increased compared with those of normotensive rats of the Wistar/Kyoto strain. Total catecholamines (mostly adrenaline) were not significantly different. 3. In the adrenal glands of 2-weeks-old and 4-weeks-old SHR activities of tyrosine hydroxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyl transferase were decreased, compared to Wistar/Kyoto rats. 4. The adrenaline-forming enzyme was elevated in the A1 and A2 regions of the brain stem of 4-weeks-old SHR and in the A1 region of adult DOCA-salt hypertensive rats. 5. In the adrenal glands of adult DOCA-salt hypertensive rats tyrosine hydroxylase activity was increased. 6. These results implicate peripheral noradrenaline-containing neurons and central adrenaline-containing neurons in the development of genetic and experimental hypertension in rats.


The role of alpha- and beta-presynaptic receptors in the regulation of noradrenaline release elicited by nerve stimulation. 1. The presynaptic mechanisms appear to be involved in the regulation of noradrenaline release during nerve stimulation. The first one. mediated by beta-adrenoceptors, operates at low frequencies of nerve stimulation, leading to an increase in transmitter release. The second one, mediated through alpha-adrenoceptors, is triggered when higher concentrations of the transmitter are reached in the synaptic cleft, leading to inhibition of transmitter release, probably through a restriction in the availability of calcium for the secretory process. 2. It is postulated that part of the anti-hypertensive effects of drugs like clonidine, alpha-methyldopa and beta-receptor-blocking agents may be related to their long-term effects on presynaptic adrenoceptors.


Pharmacokinetics of beta-receptor-blocking agents in relation to their anti-hypertensive effect. 1. Beta-Recptor-blocking drugs are rapidly and completely absorbed after oral administration. Systemic availability is nevertheless incomplete for propranolol, alprenolol and oxprenolol, owing to "first-pass' extraction by the liver. 2. Plasma half-life is between 2 and 4 h, except for sotalol (10-12 h). Plasma elimination of propranolol is reduced with decreased liver blood flow observed in congestive heart failure or during chronic propranolol therapy itself. 3. beta-Receptor blockade is usually achieved in these concentration ranges: propranolol and alprenolol, 50-100 ng/ml; oxprenolol, 500-1000 ng/ml; pindolol, 10-30 ng/ml; sotalol, 2-6 microng/ml. Higher concentrations are often found with high doses administered to hypertensive patients.


Haemodynamic long-term effects of beta-receptor-blocking agents in hypertension: a comparison between alprenolol, atenolol, metoprolol and timolol. 1. Oxygen consumption and central haemodynamics were recorded at rest and during exercise in fifty-one men with essential hypertension (W.H.O. stage I) and repeated after 1 year on a single drug: alprenolol (n equals 10), atenolol (13) metoprolol (12) and timolol (16). 2. Mean arterial pressure was significantly reduced in all groups at rest (11-18%) and during exercise (5-11%). Heart rate was significantly reduced in all groups (20-28%) at rest and (17-26%) during exercise. Owing to increase in supine resting and exercise stroke volume in the alprenolol and atenolol group, cardiac index decreased less than heart rate---in contrast to the timolol group where cardiac index was decreased 26-32%. The calculated post-treatment total peripheral resistance was significantly increased at rest and during exercise in the timolol group. In the other groups the total peripheral resistance was significantly increased at rest when sitting, but not at rest when supine and during exercise. 3. It is concluded that the major haemodynamic changes induced in subjects with moderate and mild essential hypertension by these different beta-receptor blockers are the same, but that minor differences exist with respect to effect upon stroke volume and total peripheral resistance.


Comparative anti-hypertensive effectiveness of beta-adrenoreceptor antagonists with different pharmacological properties: dose-response studies during acute and chronic administration. 1. Immediate and long-term blood pressure-lowering activity of five beta-adrenoreceptor antagonists with different ancillary pharmacological properties were compared in a randomized double-blind placebo controlled factorial trial in twenty-five previously untreated patients with stable uncomplicated essential hypertension. 2. In doses which produced similar reductions in exercise tachycardia, all drugs exerted similar anti-hypertensive activity, which was greater on systolic than diastolic pressure and greatest during exercise. 3. These effects were maximum within an hour and lasted for over 8 h after a single oral dose. 4. Blood pressure-lowering activity, particularly the reduction in exercise systolic pressure, was significantly related to the logarithm of the dose of each drug. 5. Anti-hypertensive activity was maximally enhanced after 4 weeks of sustained treatment at any given dose. There was no short-term habituation to treatment and substitution with placebo resulted in a return of the blood pressure to pretreatment values within 4 weeks without subsequent overshoot. 6. The blood pressure-lowering activity of these drugs was predominantly related to their common property of competitive antagonism of cardiac beta-adrenoreceptors; their ancillary pharmacological properties, with the exception of intrinsic vasodilator activity, played little part in this response.


Clinical pharmacokinetics of sulphasalazine. Sulphasalazine consists of 5-aminosalicylic acid and sulphapyridine both linked together by an azo bond. Sulphasalazine is clearly useful in long-term management of ulcerative colitis and may be useful in Crohn's disease. The absorption, metabolism and excretion of sulphasalazine is similar in volunteers and patients with ulcerative colitis or Crohn's disease. Sulphasalazine serves as a vehicle to deliver its possible active components, 5-aminosalicylic acid and sulphapyridine, to the colon in higher concentrations than could be achieved by oral administration of either one alone. Sulphasalazine reaches the colon mostly unchanged and is split by gut bacteria at the azo linkage, releasing 5-aminosalicylic acid and sulphapyridine. 5-Aminosalicylic acid may act locally and is not absorbed to any great extent. On the contrary, sulphapyridine is mostly absorpbed from the colon and may act both locally, during mucosal absorption, and systemically. A positive correlation exists between serum total sulphapyridine concentration and both therapeutic efficacy and toxicity. Sulphapyridine metabolism is largely determined by inherited acetylator phenotype, either slow or fast. Slow acetylators have higher levels of free sulphapyridine and lower levels of acetylated sulphapyridine than fast acetylators, and are likely to have more toxic symptoms on equivalent doses of sulphasalazine. Therapeutic effects of sulphasalazine in ulcerative colitis and Crohn's disease correlate with serum concentrations of total sulphapyridine (20 to 50 microng/ml), and toxicity with total sulphapyridine concentration greater than 50 microng/ml. Side-effects are mostly observed among slow acetylators. In long-term therapy of ulcerative colitis doses of 2 to 3g/day of sulphasalazine are most likely to sustain remissions and avoid toxicity. During therapy with sulphasalazine, determination of acetylator phenotype and total sulphapyridine concentration can guide effective dosage and avoid side-effects. A single serum sample for free and acetylated sulphapyridine concentrations is sufficient for this purpose.


Within-patient comparisons between different anti-hypertensive drugs. 1. By substituting one anti-hypertensive drug for the other in a panel of hypertensive patients equipotent doses have been determined. 2. Thus 40 mg of propranolol is equivalent to 4-5 mg of pindolol, 98 mg of practolol, 128 mg of alprenolol, 49 mg of metoprolol, 42 mg of tolamolol and 4-4 mg of timolol. 3. Bendorfluazide (10 mg) is eqivalent to 1-6 mg of bumetanide, 20 mg of chlorthalidone, 35 mg of mefruside and 3-5 mg of amiloride together with 35 mg of hydrochlorthiazide. 4. Methyldopa (250 mg) is equivalent to 6-0 mg of debrisoquine and 0-5 mg of St 600 (Boehringer), which is a clonidine-like substituted imidazoline.


Initial treatment of the young hypertensive: thiazide diuretic or beta-adrenoreceptor-blocking agent in a single daily dose? 1. Nine men aged 20-33 years with essential hypertension measured their own blood pressure at home, lying and standing, three times daily, under conditions of everyday living. The last 14 days' readings (eighty-four observations) from control and treatment periods of at least 4 weeks' duration were used to calculate mean pressures. 2. In eight patients, propranolol (40 mg thrice daily with meals) significantly lowered "mean blood pressure" (diastolic+1/3[systolic-diastolic]) but methyclothiazide (5 mg with breakfast) did not. In five subjects, prindolol (5 mg thrice daily with meals) significantly lowered "mean blood pressure" but methyclothiazide (5 mg with breakfast) did not. 3. In six subjects there was no significant difference between "mean blood pressure" when taking propranolol doses 120 mg with breakfast, 60 mg with breakfast and with the evening meal, and 40 mg with each meal. In five subjects there was no significant difference between "mean blood pressure" when taking metoprolol 200 mg with breakfast and 100 mg with breakfast and with the evening meal. In four subjects there was no significant difference between "mean blood pressure" when taking prindolol 30 mg with breakfast, 15 mg with breakfast and with the evening meal, and 10 mg with each meal. 4. In young males with essential hypertension, beta-adrenoreceptor blockers were more effective than a thiazide diuretic in lowering blood pressure, and were effective in a single daily dose.


Control of renin secretion in vivo and in vitro in rats: arguments in favour of a precursor form of renin and of a role of a microtubular system. 1. The morphology of the juxtaglomerular apparatus, plasma renin activity, plasma renin substrate and renal renin have been studied in rats after maximal stimulation by bilateral adrenalectomy and salt depletion, and also after blocking this stimulation by deoxycorticosterone and salt load. 2. After stimulation the juxtaglomerular apparatus showed a well-developed granular endoplasmic reticulum and a low secretory granule content. Plasma renin activity was markedly elevated and plasma renin substrate was low. After blockade numerous specific granules with crystalline structures were seen and the granular endoplasmic reticulum was less developed. Plasma renin activity was now low and plasma renin substrate elevated. 3. After prior acidification of the kidney extract a significant increase of renal renin was observed in both conditions but was greater in the second group at the time when large numbers of young granules containing crystalline material were seen. 4. Kidney slices from the adrenalectomized salt-depleted rats released more renin than control slices. Vincristine did not affect this release, but inhibited release from slices stimulated by isoprenaline.


Toxicology of ipecac: a review.

Toxicology of ipecac: a review. The general effectiveness and safety of Ipecac syrup, per se, has not been questioned, but rather an attempt has been made to consolidate pertinent literature dealing with the toxic manifestations of Ipecac fluid extract. Ipecac contains both emetine and cephaeline and the toxicity of Ipecac fluid extract is consistent with reports on the toxicity of both compounds. The majority of the work has involved emetine since it is in higher concentration in Ipecac fluid extract than is cephaeline. Comparison of the clinical picture presented in syrup or fluid extract of Ipecac overdose and emetine toxicity in amebiasis treatment permits us to summarize the general characteristics of Ipecac alkaloid toxicity as involving primarily gastrointestinal, cardiovascular, and neuromuscular foci.


Insect reactions related to sports.

Insect reactions related to sports. Only the rare practicing physician does not see at least a few patients during the warm summer months who have come off second best in an encounter with a member of Hymenoptera or one or the other of the various species of the phylum Arthropoda. Next to children and certain occupational groups such as farmers, it is probable that the outdoor sports enthusiast is the most frequent victim of insect stings and bites. Often the victim is not sure just what attacked him, and the physician may have to make an educated guess based on the appearance and grouping of the wounds and on the nature of the patient's symptoms. Usually, secondary infection is the most frequent possibility after these attacks. However, the hypersensitive patient who suffers immediate or delayed allergic reaction poses the greater, if rarer problem.


A plea for comprehensive treatment for the hyperkinetic child. Having a multimodality approach to the hyperkinetic child may make the difference between success or failure in the management of the child. Frequently, one or two modes of intervention alone will not be sufficient. Although several modes of intervention have been described, the helping professional must exercise his own creativity in order to assist specific children.


Metabolism and disposition of trifluoperazine in the rat. II. Kinetics after oral and intravenous administration in acutely and chronically treated animals. Male rats received 12.3 micronmol of trifluoperazine (CF3-PER) per kg orally or into the tail vein, and the kinetics of the drug and of its metabolites, 7-hydroxytrifluoperazine and desmethyltrifluoperazine, were followed from 0.5 to 8 hr after dosage. Brain, liver, lung, kidney, and plasma were analyzed by a thin-layer chromatographic method. Following iv injection, the levels of CF3-PER were much higher in brain, lung, kidney, and plasma obtained from the aorta than following oral administration, whereas the metabolite concentrations were very similar after administration by the two routes. However, CF3-PER concentrations in liver did not depend upon the route of administration. In conjunction with this fact, the poor availability of CF3-PER in the central compartment and extrahepatic tissues following oral dosage points to a pronounced first-pass effect. When CF3-PER plasma levels were measured in the portal vein of orally treated rats, the amount of drug absorbed unchanged from the intestine could be demonstrated to be 91% of the dose. A high liver extraction (about 80%) was demonstrated in vivo by sampling hepatic venous blood. Pretreatment of rats with SKF 525-A led to an impaired CF3-PER elimination and to an increase in the liver/plasma ratio. This showed that the liver extraction was due to rapid biotransformation. Orally dosed rats exhibited significantly higher levels of CF3-PER and of its demethylation product in brain, lung, and kidney when they had been pretreated for 3 weeks with 12.3 micronmol of CF3-PER per kg daily po. One and 4 hr after iv injection of 12.3 micronmol of 3H-CF3-PER per kg, total radioactivity in brain equalled the sum of the specifically analyzed compounds, whereas in lung and kidney the tritium quantity was up to 2-fold, and in liver and plasma up to 4-fold the sum of CF3-PER and its two main metabolites.


Plasma levels of real and "apparent" hydralazine in man and rat. Derivatization of hydralazine in plasma under acidic conditions yields values for the concentrations of "apparent" hydralazine that are dependent on the pH in the derivatization step. The results have been explained by postulating the existence of acid-hydrolyzable conjugates of unknown structure. These metabolites appear to be present in rat and human plasma after oral dosing. Procedures have been developed for the selective analysis of hydralazine or its acid-labile conjugates, and applied to measurements of plasma concentrations in rat and man.


Comparative metabolism of fenclorac in rat, dog, monkey, and man. Fenclorac (alpha,m-dichloro-p-cyclohexylphenylacetic acid, diethylammonium salt), a new nonsteroidal anti-inflammatory agent, was rapidly and quantitatively absorbed from the gastrointestinal tract of rat, dog, monkey, and man following oral administration of a solution of 14C-labeled compound. Radiochromatography and mass spectrometry indicated that fenclorac was the principal component in plasma during both the absorption and elimination phases in all species. Small quantities of m-chloro-p-cyclohexylphenylglycolic acid metabolite were also present. Fenclorac and metabolite were confined primarily to the plasma phase of whole blood and were extensively bound to serum albumin. The plasma elimination half-time was species-dependent and varied from 1.6 hr in the rat to 6.5 hr in the dog. The principal tissues of distribution were liver, kidney, and small intestine. There was no significant accumulation or retention of drug or metabolites in any tissue compartment. Fenclorac was completely biotransformed prior to elimination in urine and bile. The major route of elimination was renal in man and monkey, and biliary in the dog. Enterohepatic recirculation of fenclorac metabolites was shown to occur in the rat. The major urinary metabolites were hydroxycyclohexyl analogs of fenclorac and m-chloro-p-cyclohexylphenylglycolic acid. There was no difference in metabolism and biological disposition of fenclorac in normal rats and rats with adjuvant-induced polyarthritis.


Urinary metabolites of amitriptyline in the dog. Dogs excreted approximately 45% of an oral dose of 14C-amitriptyline (30 mg/kg) in the urine in 24 hr. Two new urinary metabolites of the drug were identified as dihydrodiol derivatives of amitriptyline and nortriptyline, respectively. The major metabolite in dog urine was 10-hydroxyamitriptyline, excreted mainly in conjugated form. Other metabolites were characterized as 10-hydroxynortriptyline, amitriptyline N-oxide, and nortriptyline. Together, these metabolites accounted for approximately 47% of the urinary radioactivity.


Identification of 3-O-methyl-alpha-methyldopamine as a urinary metabolite of 3,4-methylenedioxyamphetamine in dog and monkey. 3-O-Methyl-alpha-methyldopamine has been separated by gas-liquid chromatography (GC) as a metabolite of MDA in the urine of dog and monkey. The metabolite was identified as its mono- and di-trifluoroacetyl derivatives by comparison of their GC and GC-mass spectral properties with those of synthetic compounds. The amount of metabolite increased on hydrolyzing the urine from dosed dogs and monkeys with a preparation containing beta-glucuronidase and sulfatase.


Metabolism of pyrazole. Structure elucidation of urinary metabolites. Pyrazole has been widely used as an inhibitor of alcohol dehydrogenase both in vivo and in vitro. Very little attention has been paid to the metabolism of this agent and possible biological activity of any metabolites. Several isotopic variants of pyrazole, both stable and radioactive, were used in a study of its metabolic fate by gas chromatography-mass spectrometry. Seven metabolites were structurally identified and included hydroxylated and conjugated derivatives of pyrazole. Two metabolites were conjugated with a pentose, perhaps indicating that pyrazole serves as a substrate in the salvage pathway of purines and pyrimidines forming pyrazole ribosides. The use of d3-pyrazole greatly enhanced structural assignment of the metabolites by revealing the metabolism at or next to a labeled carbon atom.