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Biomedical subjects

V P Pishak

Publications and source records attributed to V P Pishak.

At least 19 recordsLinked to original sources
PubMed2002

[Pathogenetic role of prostanoids in disorders of sodium reabsorption during development of acute renal insufficiency].

The experiments were carried out on 36 male rats with an acute renal insufficiency--sublimate-induced nephropathy. An increased amount of both tromboxan A2, and prostaglandine F2a has been shown to play a pathogenic role in the disorders of the main energy-dependent process in kidney--reabsorbtion of sodium ions. The negative correlative relation between the concentration of sodium ions in plasma and an increased amount of prostaglandine E2 in a kidney papilla can be explained by the hyperfunction of the interstitial cells of a kidney papilla and with a natriuretic effect of prostaglandine E2 at the level of collective tubules.

Absorption↗
PubMed2001

[Methods of urine analysis for creatinine after long period of storage].

Our investigations showed that n-cresol (4-methylphenol) stabilized urine and preserves urinal creatinine as long as for 50-d storage at room temperature. This antimicrobial biochemical stabilizer is the core of a novel method of delayed creatinine quantification in urine. It can be useful in metabolic investigations of cosmonauts and nuclear submarine crews, members of alpine, desert, deep-water, Arctic and Antarctic expeditions and in many other cases when samples cannot be analyzed immediately.

Creatinine↗
PubMed2000

Effect of melatonin on cyclic nucleotide content and intensity of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypoxia.

Single intraperitoneal injection of melatonin in a dose of 1 mg/kg prevented accumulation of cGMP and intensification of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypobaric hypoxia (12,000 m). Changes in habenular content of cGMP suggest that melatonin prevents hypoxia-induced activation of heme-oxygenase.

Acute Disease↗
PubMed2000

[Chronobiological characteristics of renal function under conditions of T4- and T3-hyperthyreosis].

Hyperthyreosis in rats after 10 days of injecting T4 at the dose of 100 mg/kg of the body mass modified the chronostructure of renal functions by decreasing rhythms of the urinal pH mesor, and elevating rhythms of creatinine and protein excretion mesors, and the mesor and the amplitude of sodiuresis rhythms. Temporal readjustment of renal functions reflects peculiarities of the body adaptation to T4-induced hyperthyreosis. Injections of T3 (20 mg/kg of the body mass) during 10 days do not lead to any significant changes in the biorhythmic properties of the renal functions.

Animals↗
PubMed2000

[The use of antimicrobial stabilizers in biochemical research].

The ability of highly active antimicrobial biochemical stabilizers to sustain samples (T = 4 degrees C to 8 degrees C) till biochemical analysis in 20-50 days was tested. A new generation of delayed biochemical assays with the use of these stabilizers can be invoked in metabolic studies of cosmonauts and aviators, personnel of atomic submarines, pole explorers and other occupational groups.

Anti-Infective Agents↗
PubMed2000

[The mechanisms of the GABA-ergic regulation of beta-endorphin levels in the hypothalamic structures of prenatally stressed male rats].

The effect of GABA receptors agonists on the stress-induced beta-endorphin levels in the preoptic area and mediobasal hypothalamus of the intact and prenatally stressed male albino rats was studied. It has been found out that stimulation of GABAa-receptor complex by means of the muscimol leads to increasing of beta-endorphin levels in the preoptic area and mediobasal hypothalamus of the control animals. GABAb receptor activation by means of the baclofen decreases opioids level in the mediobasal hypothalamus. Prenatal stress eliminates stimulant effect of the muscimol on beta-endorphin levels in the investigated brain structures and leads to the opioid level decreasing after baclofen influence in preoptic area.

Animals↗
PubMed1999

[The effect of melatonin on photoperiod changes in the glutathione system of the brain under acute hypoxia].

The effect of acute hypobaric hypoxia against on the background of single-shot melatonin administration on the activity of glutathione ferments system (glutathione peroxidase, glutathione S-transferase and glucose-6-phosphate dehydrogenase) and the contents of reduced glutathione and malondialdehyde in the supernatant of juvenile male of white rats forebrain was investigated under three conditions of lighting--natural conditions of lighting in the spring-summer period of year, constant illumination and constant darkness during the one week. The constant illumination enhanced the lipid peroxidation with simultaneous decreasing in the activity of glutathione peroxidase in control animals. The constant illumination enhanced the lipid peroxidation with simultaneous decrease in the activity of glutathione peroxidase in control animals. The constant darkness reduced the intensity of free-radical oxidation improving the antioxidant neuron protection. The melatonin decreased the contents of malondialdehyde, raised the activity of glutathione enzyme system and eliminated the negative influence of constant illumination on forebrain antioxidant system in intact animals. The acute hypoxia resulted in the increase of lipid peroxidation and reduced the activity of antioxidant enzymes, which were most expressed in constant light conditions. The melatonin administration before of 30 minutes of acute hypoxia modeling reduced the intensity of oxidizing stress, which was generated by acute hypoxia.

Acute Disease↗
PubMed1999

[Seasonal changes in the triiodothyronine level of the blood evoked by ultraviolet irradiation in vitro].

Ultraviolet irradiation (lambda = 254 nm) of the whole blood of juvenile bulls in vitro results in a plasmatic T3 increase dependent on the time of exposure. Dynamics of the growth of hormone content because of UV varies with season. No negative correlation between plasmatic T3 and T4 in irradiated and non-irradiated blood samples was stated. Hence, increased T3 levels in blood after UV irradiation in vitro is a consequence of the output of erythrocyte-deposited hormone rather than photoactivation of the T4 to T3 conversion.

Animals↗
PubMed1998

[Materials for performing external quality control of the measurement of ceruloplasmin activity].

Quaternary monophosphonium compound 1-triphenyl phosphoniomethyl naphthalene bromide stabilizes blood serum samples and preserves the activity of ceruloplasmin (CP 1.16.3.1) intact for 30 days. For preparing the reference material, 10 ml of serum is added to 190 ml of 1.55 mM solution of this compound, left for 24 h at 4-8 degrees C, poured in small flasks, stored at the same temperature, and used as reference material as needed for checking up the correctness of ceruloplasmin measurements in biochemical laboratories.

Ceruloplasmin↗
PubMed1998

[Materials for carrying out external quality control in the determination of total protein].

Quaternary bis-ammonium compound No. 82 (QAC-82) is a highly effective antibacterial biochemical stabilizer of total protein. In concentrations of 3.4-13.6 mmol/liter, it preserves the content of protein in the blood serum for 40 days at 18-20 degrees C. For preparing reference material, 5 ml human or animal serum is added to 95 ml 5.25 mM aqueous solution of QAC-82, mixed, stored at room temperature, and used for assessing the quality of total protein measurements by the biuret method.

Biuret Reaction↗
PubMed1998

[The effect of radiation factors on cerebrovascular diseases in the region of northern Bukovina].

Correlation was studied between indices for prevalence and incidence of cerebrovascular diseases (CVD) and level of radioactive contamination in the region of northern Bukovina. As far as CVD formation, prevalence, and incidence rate is concerned, long-term exposure to small doses of ionizing radiation (cesium and strontium) makes for augmentation or lowering of CVD levels depending on their form, age, and place of residence of those having become victims of the Chernobyl accident.

Adult↗
PubMed1998

[Material for external assessment of quality of glucose analysis].

9,10-bismethyltriphenylphosphoniumanthracene iodide (BPA) in concentrations 1.25-3.75 mmole/liter stabilizes blood serum and preserves glucose in it for 990 days at 4-8 degrees C. For preparing reference material, 200 ml human or animal serum is added to 800 ml 3.125 mM BPA solution, mixed, exposed for 24 h at 4-8 degrees C, centrifuged, the resultant preparation is stored at the same temperature and used as reference material for assessing the quality of glucose measurements by o-toluidine method at biochemical laboratories. The reference material is fit for tests for at least 990 days.

Blood Glucose↗
PubMed1996

[The adaptive characteristics of the small intestine under chronic experimental conditions].

The influence of local substrate loads, both monomeric (glucose) and dimeric (saccharose) ones, on the interrelations between the hydrolysis and transport processes was studied under conditions of a chronic experiment on rats with isolated portions of the small intestine. The use of different substrate loads (glucose, saccharose) made it possible to reveal a difference in the response of various portions of the small intestine. The distal portions are more sensitive to loading than the proximal ones.

Adaptation, Physiological↗
PubMed1991

[The content of cyclic nucleotides in the blood of patients with chronic type-A and -B gastritis].

A study of the content of cyclic nucleotides in patients with chronic gastritis indicates that the level of cAMP and cGMP undergoes various changes. The cGMP/cAMP ratio was in gastritis of the A type higher than in the healthy and in the B gastritis type lower. It is concluded that chronic gastritis is accompanied not only by changes of absolute values of the level of cyclic nucleotides but also by changes of the cGMP/cAMP ratio.

Adult↗