[The mastering and maintenance of skills at the parasitological diagnosis of malaria in nonendemic areas]. / Osvoenie i podderzhanie navykov parazitologicheskoi malarii v usloviiakh neéndemichnykh territorii.

The paper describes a method for mastering and maintaining skills at the parasitological diagnosis of malaria. The number of educational blood smears, which are to be studied to develop reliable skills at the detection of malaria parasites in the smear preparations showing different level of parasitemia, has been determined. It has been ascertained that parasites that develop with the use of antimalaria drugs may be reliably detected by a skilled parasitologist who constantly uses his experience in practical work. The experiment has indicated that parasitologists and laboratory assistants should monthly view collections of educational smear preparations in nonendemic areas in order to maintain their skills at the parasitological diagnosis of malaria.

[Autoradiographic characteristics and negative effects of radionuclide elimination from the body using sorbents]. / Gistoavtoradiograficheskaia kharakteristika i negativnye éffekty vyvedeniia iz organizma radionuklidnov s pomoshch'iu sorbentov.

It is shown that 210Po in the complex with a sorbent can be fixed in the organs, particularly in the proximal renal tubules. This, in the authors' opinion, can be the cause of various complications of the therapy with the adsorbents including the development of tumours.

[Characteristics of the contractile reactions of rhythmically active vascular smooth muscles in spontaneously hypertensive rats undergoing hyperoxygenation and the role of the endothelium in their development]. / Osobennosti sokratitel'nykh reaktsii ritmicheski aktivnykh gladkikh myshts sosudov spontanno gipertenzivnykh krys pri giperoksigenatsii i rol' éndoteliia v ikh razvitii.

Experiments on isolated preparations of the portal vein from healthy and spontaneously hypertensive rats have revealed that removal of the endothelium has no influence on hyperoxygenation-induced increase in the contractile activity of vascular smooth muscles (VSM). It is also shown that VSM from hypertensive rats demonstrate higher sensitivity to hyperoxygenation than VSM from healthy rats. Results of the study confirm a supposition that contractile effect of hyperoxygenation on VSM is realized mainly via direct influence of oxygen on plasma membranes of VSM and increase of the membrane permeability for extracellular Ca2+.

[Cellular mechanisms of transitory smooth muscle contraction of the coronary arteries during hypoxia: role of intracellular Ca2+]. / Kletochnye mekhanizmy tranzitornogo sokrashcheniia gladkikh myshts koronarnykh arterii pri gipoksii: rol' vnutrikletochnogo Ca2+.

In experiments on isolated porcine and canine coronary artery rings it was shown that vascular smooth muscle (VSM) during hypoxia (decreasing bath PO2 with 147 to 20-15 mm Hg) response to biphasic constriction-dilation reaction. Transient hypoxic contractions (THC) of VSM preserved completely in Ca2+-free solution and partially (up 50-60%) in the presence of Ca2+-channel blockers, but abolished by procaine. THC of VSM skinned by saponin significantly depressed at depletion of Ca2+-store sarcoplasmic reticulum (SR) by caffeine nd abolished after SR destruction. THC is not linked with Na+-K+-ATPase inhibition because it preserved (or increased) at ouabain treatment. THC significantly depressed under selective glycolysis blockade by monoiodoacetic acid and pyruvate and also after inositol-1 monophosphatase inhibition by lithium (the phase of hypoxic relaxation of VSM was augmented in this condition). Our results indicate that transient contraction of coronary arteries under hypoxia may be mediated mainly by release of Ca2+ from SR and linked obviously with production of inositol-1,4,5-trisphosphate. The participation of glycolysis in this process is unknown.

[Magnesium ions and contractile activity of vascular smooth muscle cells in hypoxia]. / Iony magniia i sokratitel'naia aktivnost' gladkomyshechnykh kletok sosudov pri gipooksigenatsii.

In isolated smooth muscle of the rat portal vein removal of Mg2+ from perfusate induced rapid enhancement of frequency and amplitude of spontaneous contractions and decreased inhibiting effect of hypoxia on the smooth muscle contractile activity. Concomitant elevation of extracellular Ca2+ has no additional protective effect on the smooth muscle in hypoxia. Ten-fold lowering of Mg2+ content in buffer solution resulted in a significant rise in the tension of the smooth muscle activated by Ca2+. The data obtained suggest that protective effect of Mg2+-free solution on vascular smooth muscle in hypoxia may be mediated not only through increases intracellular Ca2+ concentration but also due to rising sensitivity of the smooth muscle cells contractile protein to Ca2+.

[Cellular mechanisms of hypoxic coronary spasm]. / Kletochnye mekhanizmy gipoksicheskogo koronarospazma.

Transient hypoxic contraction (THC) of vascular smooth muscle (VSM) of isolated human, canine and porcine coronary artery rings was preserved in Ca2+--free solution and abolished with procaine. The data obtained suggest that the THC of the coronary VSM is mediated via a Ca2+ release from sarcoplasmic reticulum under the effect of inositol-1,4, 5-triphosphate and may be triggered by action of endogenous noradrenaline on alpha 1-adrenoceptors. The mechanism of beta-adrenergic relaxation was not actualized in the hypoxia because of uncoupling of the beta-adrenoceptors from adenylate cyclase.

[Role of the endothelium in the development of the contractile reactions of vascular smooth muscle during decreased oxygenation]. / Rol' éndoteliia v razvitii sokratitel'nykh reaktsii sosudistykh gladkikh myshts pri snizhenii ikh oksigenatsii.

Noradrenaline-preactivated vascular smooth muscles (VSM) of the rat thoracic aorta showed two-phase reactions in response to decreased oxygenation: significant relaxation was preceded by transient constriction. When the endothelium was removed only VSM relaxation phase was retained, with no constriction observed. The data obtained suggest an endothelium-dependent nature of VSM constriction reaction to hypoxia, in contrast to endothelium-independent VSM relaxation. Intracellular calcium is also assumed to play an essential role in the formation of endothelium-dependent constriction VSM reaction to hypoxia.

[Mechanism of changes in the calcium permeability of the sarcolemma of vascular smooth muscle cells during hypoxia]. / Mekhanizmy izmeneniia kal'tsievoi pronitsaemosti sarkolemmy gladkomyshechnykh kletok sosudov pri gipoksii.

In isolated preparations of smooth muscle of the rat portal vein, removal of Ca2+ from perfusate or addition of Ca2+--antagonists as well as hypoxia entailed inhibition of vascular smooth muscle contractile activity. Uptake of 45Ca by vascular smooth muscle cells was diminished in hypoxia. Liposomes filled with Ca2+ or Cr but not ATP prevented the hypoxic relaxation of vascular smooth muscle. One of the main reasons of the decrease of vascular smooth muscle contractility in hypoxia seems to be the disturbance of calcium channel phosphorylation and the decrease of sarcolemma calcium permeability.