Anticonidiogenic effect of hydroxyurea on Neurospora crassa]

Conidiation induced in a low sugar-ammonium medium (or by other means such as full starvation or heat shock) is almost fully prevented by hydroxyurea. In a parallel manner the DNA/RNA and DNA/protein ratios are prevented from increasing.     

Vanadium induced hemolysis of vitamin E deficient erythrocytes in Hepes buffer

Several vanadium compounds were tested for their ability to induce in vitro hemolysis of vitamin E-deficient hamster erythrocytes. Free vanadyl caused hemolysis in Hepes buffer but not in Tris or phosphate buffer, while hemolysis was inhibited by catalase, chelators such as deferoxamine mesylate and EDTA, and hydroxyl radical scavengers such as ethanol andd-mannitol. Although metavanadate itself could not induce hemolysis, metavanadate with NAD(P)H caused hemolysis in Hepes buffer only, and superoxide dismutase prevented it. Hydrogen peroxide, hydroxyl radical and Hepes radical were involved in vanadyl-induced hemolysis; superoxide anion was further involved in metavanadate plus NAD(P)H-induced hemolysis. Vitamin E prevented hemolysis under both conditions.     

Selective depletion of spinal noradrenaline inhibits post-decapitation convulsions in rats

Summary Local administration of 6-hydroxydopamine in the subarachnoidal space of the spinal cord in rats resulted in a selective long-lasting depletion of spinal noradrenaline, but not of dopamine, and prevented the occurrence of postdecapitation convulsions.     

Endotoxin-induced acceleration of ovum transport in rabbits.

Salmonella enteritidis-Boivin endotoxin (1--20 microgram/kg) induced accelerated oviductal ovum transport in rabbits in a dose-related manner. Indomethacin prevented this effect. Levels of prostaglandin E and F in uterine vein blood increased following endotoxin injection.     

Vanadium induced hemolysis of vitamin E deficient erythrocytes in Hepes buffer

Several vanadium compounds were tested for their ability to induce in vitro hemolysis of vitamin E-deficient hamster erythrocytes. Free vanadyl caused hemolysis in Hepes buffer but not in Tris or phosphate buffer, while hemolysis was inhibited by catalase, chelators such as deferoxamine mesylate and EDTA, and hydroxyl radical scavengers such as ethanol andd-mannitol. Although metavanadate itself could not induce hemolysis, metavanadate with NAD(P)H caused hemolysis in Hepes buffer only, and superoxide dismutase prevented it. Hydrogen peroxide, hydroxyl radical and Hepes radical were involved in vanadyl-induced hemolysis; superoxide anion was further involved in metavanadate plus NAD(P)H-induced hemolysis. Vitamin E prevented hemolysis under both conditions.     

Effect of diazepam (Valium®) on chronic stress-induced hypertension in the rat

Summary Chronic treatment with diazepam was effective in preventing chronic stress-induced hypertension in rats. It also prevented the stressful stimuli from maintaining a hypertensive level in animals previously made hypertensive by chronic stress.     

Effect of suppression of endocrine or exocrine pancreatic function in hemorrhagic shock.

Somatostatin did not influence the pathologic consequences of hemorrhagic shock, but pancreatic duct ligation prevented the post-oligemic decline of arterial pressure and formation of toxic factors. These results indicate that pancreatic acinar cells release myocardial depressant factor and are important in the pathophysiology of shock.     

中国纳米科技现状分析与思考

纳米科技因其技术含量高、涉及范围广而引起各国的重视。我国在纳米科技的研发中投入了大量的人力、物力,但由于在科技改革体制中还存在一些问题,以及人们对纳米科技理解的片面性,影响了纳米科技的发展。为了实现纳米科技的可持续发展,我们对中国纳米科技的现状进行了分析与思考。     

Inhibitory effect of galactose on hydrogen transfer in the hemolymph ofVespa orientalis

Summary The generation of pyruvate and lactate inVespa orientalis hemolymph is prevented by the presence of galactose. The inhibitory effect is possibly produced by a competition for NAD and occurs in concentrations of 0.05 M.     

Histamine H1- and H2-receptor-mediated gastric microcirculatory effects in the aetiology of stress ulceration in the rat stomach

Stress produced severe mucosal ulcers, increased mucosal microcirculation and lowered mast cell counts in the glandular wall of rat stomachs. Mepyramine i.m. or metiamide i.p. effectively prevented both ulceration and microcirculatory changes but not stress-reduced mast cell counts.     

In vivo degradation of noradrenaline by MAO A in locus coeruleus of the rat

Depletion of noradrenaline in locus coeruleus neurons after reserpinization was prevented by clorgyline, a selective inhibitor of MAO A, but not by deprenyl, a selective inhibitor of MAO B. Only MAO A is therefore responsible for the degradation of homoneuronal noradrenaline in locus coeruleus nerve cells.     

Effect of glucocorticoids on the appearance of gamma-glutamyl transpeptidase activity in primary cultures of adult rat hepatocytes

Primary cultures of adult rat liver parenchymal cells showed a progressive rise of gamma-glutamyl transpeptidase (GGT) activity (E.C. 2.3.2.2) after the first 5 days of culture. The presence of dexamethasone and other synthetic glucocorticoids in the culture medium partially prevented this increase.     

5-hydroxytryptamine induced changes in body temperature of newborn kittens and guinea-pigs and the effect of indomethacin thereon

During the first days of life 10 microgram i.c.v. 5-HT evoked a primary, short-lasting hyperthermia in kittens and hypothermia in guinea-pigs. In both species, a secondary late hyperthermia occurred that could be prevented by indomethacin pretreatment.     

The role of vitamin E in preventing the hemolysis of kid and chick erythrocytes with Tween 20

Summary Erythrocytes of vitamin E-deficient kids and chicks were hemolyzed at concentrations of Tween 20 above 1%. In vivo or in vitro uptake of vitamin E by the erythrocytes, or the addition of dithiothreitol or 2-mercaptoethanol, prevented the hemolysis with Tween 20.     

Evidence that a 'critical period' is involved in early estrogen-induced LH- and FSH-release during the estrous cycle in the rat

LH- and FSH-release, which occurred in the afternoon of diestrus 1 following estradiol benzoate administration in the morning of estrus, was completely prevented by pentobarbital, when injected on diestrus 1 at 13.30 h.     

Influence of the thymus hormone on radioleucosis in mice]

A partially purified thymic extract has determined the development of leucosis in 10 thymectomized irradiated CC57Bl mice out of 25. The pure hormone isolated from the same extract prevented the development of leucosis in intact irradiated Mice. This seems to indicate the presence of a second active substance in the extract (enhancing the development of the leucosis).     

The protective effect of polyriboinosinic acid-polyribocytidylic acid against the occurrence of galactosamine-induced liver cell injury in rat

A marked increase of serum transaminase activities, histological changes of livers similar to those seen in viral hepatitis in man, and inhibition of hepatic protein synthesis were observed in rats following a single injection of D-galactosamine-HCl. These galactosamine-induced phenomena were prevented by the pretreatment of polyriboinosinic acid-polyribocytidylic acid 24 h before the galactosamine administration.     

Naloxone prevents the analgesic action of alpha-MSH in mice

alpha-MSH (0.1, 1, 10 micrograms) was administered intracerebroventricularly and its action on pain sensitivity was investigated by the hot-plate method in mice. alpha-MSH produced dose-dependent analgesia and this analgesic effect was prevented by naloxone (1 mg/kg, s.c.). It is possible that alpha-MSH may play a role in the mechanism of pain through endogeneous opioid systems.     

Effect of streptozotocin diabetes on adenosine-5′-triphosphate,oxygen consumption and steroidogenesis in testis mitochondria from rats

Summary The activity of the enzyme cleaving the side-chain of cholesterol (rate limiting step in steroidogenesis) was considerably reduced in experimentally induced diabetes. This result was accompained by both an increase in oxygen consumption and an increase in ATP synthesis. Insulin treatment prevented them.