The effect of dimethyl sulfoxide on tissue distribution of gentamicin

Summary Dimethyl sulfoxide (DMSO) and gentamicin were administered to rats i.p. No significant differences in gentamicin tissue concentrations were found between rats receiving DMSO and gentamicin, and rats receiving gentamicin alone. DMSO does not increase the tissue concentrations of gentamicin.     

反相高效液相色谱测定庆大霉素效价方法的研究

建立了反相高效液相色谱（Reverse Phaseliquid Chromatography,RP—HPLC）测定庆大霉素效价的方法,结合管碟法所做的生物效价进行比较,其相关度R。：0．9823,RSD：1．29,证明RP—HPLC可直接测定庆大霉素的效价,从而解决了生测效价程序复杂,人为误差大的问题。RP—HPLC测定方法：采用岛津高效液相色谱SPD．IOAVP、UV．VIS、LC．IOATVP,PepMapC18Trs4．6×150mmSilicaC18（5μm300A）PhenomenexODS色谱柱,流动相MILLI-Q水：冰醋酸：甲醇（比例为25：5：70）配置0．02mol／L庚烷磺酸钠溶液,流速1．0mL／min,检测波长330nm,检测灵敏度0．020AUFS,柱温为室温,进样量20μL,在10min内可对样品液中C1、C1a、C2a、C24种物质同时进行定性定量测定。     

Changes in gentamicin pharmacokinetics after reduction of renal parenchyma

Summary The relationship between the elimination constant of gentamicin and the percentage of functioning nephrons in rats cannot be characterized by a simple linear relation. The results support the assumption that gentamicin elimination per residual nephron increased.     

Zur Frage der Wirkung von DTPA auf Säugerchromosomen in vitro

Summary The influence of DTPA on the chromosome aberration rate of Chinese hamster cells in culture was studied. No increase of the aberration rate was observed after treatment with 10^–2 and 10^–3 M concentrations.     

Direct observation of the NAD glycohydrolase reaction in human erythrocytes using NMR spectroscopy

Summary The hydrolysis of NAD by the extracellular membrane-associated enzyme NAD glycohydrolase was shown to be readily followed in concentrated suspensions of human erythrocytes using¹H spin-echo nuclear magnetic resonance spectroscopy (NMR). The maximal rate of the reaction was determined and the inhibitory effect of nicotinamide was confirmed by direct NMR observation. In addition, arginine, ergothioneine and iodoacetate did not influence the reaction rate.³¹P NMR analyses of reaction media from whole cells showed that no extraneous degradation of NAD occurred and the only phosphate-containing product was ADP-ribose.The work was supported by the Australian National Health and Medical Research Council     

Magnesium enhances human pancreatic elastase digestion of125I-labeled elastin

Summary The effect of some divalent cations, especially Mg⁺⁺, on elastinolysis by porcine or human pancreatic elastase has been determined using¹²⁵Iodine-labeled elastin as substrate. Elastin degradation was significantly increased in the presence of 10^–3 M Mg⁺⁺. If elastin was pre-incubated with 0.5 (w/v) Triton, there was a further increase in elastinolysis to 2.6 times the original rate.     

Adrenaline and the electrogenic sodium pump inRana catesbeiana sympathetic ganglion cells

Summary The effect of adrenaline on the Na⁺-pump in bullfrog (Rana catesbeiana) sympathetic ganglion cells was studied by use of electrophysiological methods. The rate of removal of excess Na⁺ injected into a ganglion cell was increased by adrenaline. The K⁺-activated hyperpolarization of cell membrane, which might be produced by an electrogenic Na⁺-pump, was also increased by adrenaline. These results suggested that adrenaline was able to accelerate the Na⁺-pump, possibly the electrogenic Na⁺-pump.     

Successful cryopreservation of auricle fragments from rat hearts at −196°C

Summary The influence of electrolyte composition and glucose concentration of a cryprotective medium on the survival of auricle fragments from adult rat hearts after storage at –196°C was investigated. Using a K⁺-, Mg⁺⁺-, Ca⁺⁺-rich solution with increased glucose concentration, a high rate of surviving fragments was found after cryopreservation.     

Über eine selektive Mitosehemmung und -schädigung bei jungen Ratten durch Synthalin A

Summary A single subcutaneous injection of synthalin-A does not affect the cytoplasma ofA-cells in pancreatic islets of the rat during the 1^st–5^th day of life, in contrast to adult animals. Selective action was found on mitoticA-cells: reduction of mitotic frequency to 25% of the normal rate, and pathological mitoses in the sense of the so-called primary effect. The mitoses ofB-cells, exocrine pancreatic cells and intestinal epithelia seemed to be unchanged, although the mitotic rate was higher than inA-cells.     

Influence of common bile duct cannula size on maximal secretory rate of taurocholate in the rat

Summary The common bile duct of male Sprague-Dawley rats was cannulated with either PE 10 or PE 50 tubing. Maximal secretory rate of taurocholate averaged 389±67 (SD) and 657±115 nmoles·min^–1·g liver^–1 in the PE 10 and PE 50 group, respectively (p<0.005). Maximal bile secretory pressure was significantly higher in the PE 10 group (240±28 vs 174±8 mm H20; p<0.005). When the maximal secretory rate was exceeded, bile flow decreased in both groups but this was accompanied with a decrease in maximal bile secretory pressure in the PE 10 group only. Maximal secretory rate of bile salts is markedly influenced by experimental technique. Use of small caliber common bile duct cannulae leads to partial obstruction and decreases the apparent maximal secretory rate for taurocholate.Acknowledgments. J. Reichen was the recipient of a Faculty Development Award in Clinical Pharmacology from The Pharmaceutical Manufacturer's Association Foundation, and is the recipient of a Research Career Development Award (KO4 AM 1189) from the National Institutes of Health. Supported by National Institutes of Health grant RO1 AM 27597.     

Place de la prolyl hydroxylase dans la synthèse du collagène de cellules KB

Summary KB cells, which synthetized collagen at a low rate, shown a prolyl hydroxylase activity at the same rate that fibroblast. The relationship between collagen synthesis and prolyl hydroxylase activity in these cells was discussed.

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Ce travail a bénéficié d'une aide du CNRS (AI n^o 031218 et RCP n^o 08533) et de l'U.E.R. de Biologie Humaine de l'Université de Lyon.     

Synergistic effect of acute hypoxia on flow-induced release of ATP from cultured endothelial cells

Human umbilical vein endothelial cells (HUVECs) in primary cultures were perfused under normoxic or hypoxic conditions. These cells were stimulated twice for 3 min by increased flow (from 0.5 to 3.0 ml/min). Under hypoxic conditions the basal release of ATP was the same as under normoxic conditions, but during increased flow the release was greater (0.58±0.07>0.32±0.04 pmoles/ml/10⁶ cells (+78%), for the first period of stimulation; 0.39±0.05>0.22±0.03 pmoles/ml/10⁶ cells (+79%) for the second period). Further experiments with sequential increments in flow rate showed that under both normoxic and hypoxic conditions, a positive correlation existed between ATP release and the rate of flow but there was always more ATP released under hypoxic conditions regardless of the flow rate.HUVECs in secondary culture (second passage) were similarly stimulated. No differences were observed between normoxic and hypoxic conditions. In both cases, the quantity of ATP released during high flow (0.050±0.004 pmoles/ml/10⁶ cells) was significantly smaller than the quantity of ATP released during low flow (0.09±0.01 pmoles/ml/10⁶ cells).To conclude, since hypoxia alone did not affect ATP release, there appears to be a synergistic relationship between increased shear stress and hypoxia in the stimulation of ATP release from HUVECs. Moreover, the release of ATP under these conditions seems to be a property of highly differentiated endothelial cells.     

The turnover of F-actin-bound ADP in vivo

Summary A procedure for estimating the rate of turnover of F-actin-bound ADP in vivo is described. A turnover rate of 0.88 h^–1 was determined for mouse muscle F-actin. The validity of the method when used to estimate the turnover rate of F-actin per se is discussed in relation to the possible exchange of F-actin-bound ADP.Acknowledgments. The invaluable technical assistance of Mr L. Carrington is gratefully acknowledged.     

Gastrin stimulated H+ secretion in amphibian gastric mucosa: Effect of tetrodotoxin

Summary The role of neural mechanisms in gastrin stimulated H⁺ secretion was studied using amphibian gastric fundic mucosa. Spontaneously secreting mucosae were converted to resting state (zero H⁺ secretory rate) using Burimamide. Following removal of burimamide, 3×10^–6 M tetrodotoxin did not block gastrin stimulation of H⁺ secretion indicating that neural mechanisms are not required.This work was supported by U.S. Public Health Service NIH Grant AM17315 and by the Medical Research Service of the Veterans Administration.     

庆大霉素产生菌GntB基因的克隆与转化

根据小单孢菌产生庆大霉素的生物合成机理,利用基因克隆方法从棘孢小单孢菌（Micromonospora echinospora）基因组中扩增出庆大霉素生物合成的关键酶基因—2-脱氧青蟹肌糖合成酶基因（GntB）,并将其通过大肠杆菌／链霉菌穿梭质粒pIJ699转化原菌株,采用硫链丝菌素抗性基因启动子带动2-脱氧青蟹肌糖合成酶基因在棘孢小单孢菌细胞中实现了转化。     

Zur Wirkung von Zn++ auf die Nukleinsäurebiosynthese von Aszites-Tumorzellen

Summary Ascites tumour cells have been employed to study the reactivity of Zn⁺⁺ on nucleic acid biosynthesis. 10^–4 M Zn⁺⁺ caused a selective inhibition of DNA synthesis of intact cells. The rate of RNA- and protein-biosynthesis, however, remained unchanged. The activity of DNA polymerase as well as DNA dependent RNA polymerase was strongly affected by Zn⁺⁺ in vitro.     

Phtalocyanine in wässriger Lösung. Zum Mechanismus der Metallkomplexbildung

Summary The mechanism of incorporation of different mental ions into phthalocyaninetetrasulfonic acid in aqueous solution has been investigated. It was found that the rate of the reacion with Cu²⁺ depends on the dissociation rate of the N-H-bond of this porphyrin-like chelating agent, whereas the reaction rate with other metal ions, like Zn²⁺, does not.

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II. Mitt. Siehe I. Mitt.:K. Bernauer undS. Fallab, Helv.44, 1287 (1961).

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Herrn Prof. Dr.H. Erlenmeyer sind wir für sein reges Interesse an dieser Arbeit zu bestem Dank verpflichtet.     

Sex-dependence in triglyceride metabolism in response to dietary carbohydrates

Summary In humans, as well as in mice, fed on high carbohydrate diets, there was a significant sex difference in the plasma triglycerides in that males had higher levels than females. This was mainly due to the difference in their removal rate of circulating triglycerides in the animals of both sexes. In mice, males had higher levels of liver triglycerides as well as higher rate of incorporation of U-¹⁴C-glucose into liver triglycerides when compared to females.     

Induction of the in vitro p-hydroxylation of14C-amphetamine stereoisomers in phenobarbital-treated rats

Summary The rate of p-hydroxylation of¹⁴C-(-)-amphetamine by liver microsomes was higher than that of (+)-isomer in phenobarbital-treated male rats. The apparent K_m values for (-)- and (+)-amphetamine hydroxylation were 4.54×10^–5 M and 2.27×10^–5 M respectively, in both treated and control animals.     

Microbial degradation of bitumen

Summary A blown bitumen Mexphalte R 90/40 with a high content of saturated hydrocarbons was degraded by several microorganisms to the same extent. In batch cultures ofSaccharomycopsis lipolytica, maximal biodegradation was estimated to be about 9% w/w, 3.2·10^–3 g/cm² and 3.1·10^–3 cm of degraded bitumen. The Mexphalte R 90/40 degradation rate was closely coupled to biofilm formation. The microbial activity concerned predominantly the oxidation of saturated hydrocarbons. A direct distillation bitumen 80/100 with a low content of saturated hydrocarbons and a high content of aromatic hydrocarbons and resins was more resistant to biodegradation.