The effect of an alpha-adrenoblocker and a calcium-channel blocker on the spontaneous tonus of an isolated blood-perfused artery]

The existence of spontaneous myogenic tone was shown on an experimental model of an isolated artery perfused "ex vivo" with blood from the rat donor. Administration of the alpha-adrenoblockers prasosine and yohimbine into the perfusion medium in the bath was followed by a 60% decrease in the myogenic tone. The nonspecific blocker of calcium channels CaCl2 decreased the rest of the tone by 15%. The remaining 20-25% of the initial myogenic tone was inhibited by sodium nitroprusside. Urethane (300 mg/kg) or nembutal (20 mg/kg) injected intravenously into the rat donor may lead to an increase or a decrease in the myogenic tone, respectively. The conclusion is made that the advantage of the experimental model proposed lies in the existence of the spontaneous myogenic tone of an arterial vessel depending on humoral catecholamines and some other vasoconstrictor factors.     

The Peptide ACTH4–7-PGP Corrects Behavior and Corticosterone Levels in Rats in Chronic Stress

Neuroscience and Behavioral Physiology - The peptide ACTH4–7-PGP has a wide spectrum of neuroprotective actions, including antioxidant and antidepressant effects in stress conditions. One...     

Latex agglutination test for rapid and retrospective diagnosis of meningococcal infection

Patients with clinical manifestations of meningococcal infection were examined for verification of diagnosis. The authors conclude that repeated combined analysis of the cerebrospinal fluid and serum is needed for verification of meningococcal infection in patients with typical clinical symptoms. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 541–544, November, 1999     

Participation of calcium ions in the molecular mechanism of cardioprotective action of exogenous phosphocreatine

Summary The purpose of this study was to find out whether Ca²⁺ is necessary for the protective effect of phosphocreatine (PCr) on ischemic myocardium. Isolated Langendorff-perfused rat hearts were used in the study. When ischemic arrest was induced in Ca²⁺-free buffer, PCr did not exert a protective effect on ischemic myocardium. PCr improved postischemic contractile recovery of hearts subjected to ischemia in perfusion media containing 0.5 and 1.2 mmol/l Ca²⁺.Phosphoarginine, a structural analogue of PCr which possesses Ca²⁺-binding property similar to that of PCr did not exert any protective effect on ischemic myocardium. The effects of PCr and Ca²⁺ on lipid order of sarcolemmal vesicles from canine heart were studied by using ESR spectroscopy. PCr made membrane phospholipids more tightly packed at mildly acidic and neutral pH, but did not at pH 8.5. Although Ca²⁺ itself did not influence the membrane structure at pH 5.5, it potentiated the effect of PCr on sarcolemmal phospholipids. Thus, the protective effect of PCr on ischemic myocardium is not attributed to its Ca²⁺ binding properly, but Ca²⁺ is a necessary component of the mechanism of protective effect of PCr on ischemic myocardium.     

The use of fludarabine phosphate (Fludara) to treat chronic B-cell lymphocytic leukemia and non-Hodgkin's lymphoma resistant to standard chemotherapy

Following monochemotherapy with fludarabin phosphate (fludara), complete (18%), and partial remission (27%) with stabilization (45%) was recorded in patients with B-cell chronic lymphocytic leukemia, most of whom were resistant to alkylating cytostatic drugs and their combinations containing anthracyclines. Long-term remission was registered in patients with low and moderate grade non-Hodgkin's lymphoma, resistant to standard cytostatic treatment, due to the therapeutic synergism of fludara and cytosinarabinoside (FAVAMP).     

Effect of endothelin-1 on cardiovascular parameters of lewis and wistar rats in immobilization stress

Effect of low doses of endothelin-1 on the dynamics of blood pressure and heart rate is studied in Lewis and Wistar rats during 1-h immobilization stress. It is shown that endothelin-1 significantly lowers blood pressure in stress-sensitive Lewis rats during stress and has no effect on hemodynamic parameters in immobilized stress-resistant Wistar rats in comparison with the control. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 3, pp. 275–278, March, 1998     

Arterial pressure lability in hypotensive effects of clonidine in barodenervated spontaneously hypertensive rats

Hypotensive effect of clonidine and its effect on arterial pressure lability as the main index of stability of background blood pressure are studied in intact spontaneously hypertensive rats (SHR) and rats with chronic sinoaortic denervation. Barodenervation potentiates hypotensive and negative cardiochronotropic effects of clonidine, which is accompanied by reduced blood pressure lability. This indicates an increased sensitivity of central α₂-and imidazoline receptors, which mediate the depressor effect of clonidine, against the background of chronic inhibition of the baroreceptor reflex. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 9, pp. 295–297, September, 1997     

Synthesis and hemodynamic effects of a new endothelin-converting enzyme inhibitor

A new endothelin-converting enzyme inhibitor PP-35 including N^α-benzylsuccinyl group and Leu-Trp-OH dipeptide is synthesized. Similarly to phosphoramidon substance PP-35 abolishes elevation of systemic blood pressure and heart rate decrease in normotensive rats in response to bolus injection of big endothelin-1. Hemodynamic responses to endothelin-1 remain unchanged. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 11, pp. 526–529, November, 1998