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Biomedical subjects

R I Aĭzman

Publications and source records attributed to R I Aĭzman.

At least 19 recordsLinked to original sources
PubMed2005

[Mitotic activity of pial microvascular endothelium rat in postnatal ontogenesis].

Mitotic activity of endothelium in pial microvessels has been studied with the aid of intra-vessel autoradiography in 4-, 12- and 30-day old rats using these parameters: number of labeled nuclei per vessel or per 100 mcm of its length, or per 1 mm2 endothelial surface area, as well as number of vessels with labeled endothelium cells. The first parameter was independent of vessel diameter. The other parameters had highest value in the pericapillary vessels in all rats. These values decrease with rat age. The highest rate of brain growth was revealed after reaching the greatest mitotic endothelium activity in pial bed.

Aging↗
PubMed2004

[Proliferative activity of blood microvascular endothelium of intestinal mesentery during rat postnatal ontogenesis].

The study of mitotic activity of mesenteric microvascular endothelium cells (EC) in 4-, 12-, and 30-day old rats has been carried out using following parameters: number of labeled nuclei per vessel, or per 100 microm of vascular length, or per 1 mm2 of endothelial surface area, as well as shares of labeled EC and of vessels with labeled EC, have been estimated. The highest density of labeled nuclei was revealed in the pericapillary vessels in all rats. Its values were significantly higher in 12-day-old rats and were the lowest in 30-day-old ones.

Animals↗
PubMed2003

[Effect of natural zeolites on renal functions and water-salt metabolism in rats].

In vivo experiments on adult Wistar rats, it has been found that intake of natural zeolites resulted in temporary decrease of renal water, sodium and potassium excretion. At the same time, reabsorption of water and electrolytes increased. This effect was due to the stimulation of Na+, K(+)-ATPase activity in thick ascending limb of Henle loop and hormonal changes: increase of insulin, thyroxin and aldosterone concentration in plasma. The water and ion content in most of the tissues under study was higher in the experimental group than in control. It has been suggested that renal response in rats with zeolites intake was compensatory lower as a result of gastrointestinal losses of ions and ion accumulation in tissues.

Animals↗
PubMed2003

[Characteristics of the K(+)-ion transport in the rat intestine following the use of natural zeolites as food additives].

Effects of zeolites as a food supplement have been studied on Wistar rats both in vivo perfusion experiments in the jejunum and distal colon and Rb fluxes through intestinal wall in the Ussing chamber. It has been found that zeolites decrease the K+ absorption and stimulate K+ secretion in the gut. This effect was due to inhibition of the apical N(+)-K(+)-ATPase and ouabain-sensitive Na(+)-independent K(+)-ATPase as well as the activation of the basolateral N(+)-K(+)-ATPase.

Animals↗
PubMed2001

[Effect of the water deprivation during pregnancy on the water-salt tissue composition and kidney function in the rat offspring of the first and second generation].

Rats were subjected to intermittent water restriction from the 1st day of pregnancy until delivery. Water, sodium, and potassium contents in the liver, brain, skeletal muscles, heart, kidneys, and subcutaneous fat tissue were determined in the litter. Water and sodium contents in 30-day old rats of the 1st and 2nd generation were found to be comparable to the control values. Water loading resulted in weaker diuretic responses in the former rats as compared with the control. No differences in the renal response were revealed in adult rats.

Animals↗
PubMed2000

[Age characteristics of K(+) transport in the rat distal colon].

In vitro and in vivo experiments with perfusion in 20- and 60-day old rats revealed that K+ absorption in the gut as well as 86Rb uptake in the distal colon was significantly higher in younger rats due probable, to the higher activity of the apex-located K+-dependent ATPase and lower activity of the basolateral K+-carriers. The luminal blockade of K+ absorbing pumps with ouabain or omeprazole resulted in a decrease of the K+ absorption and K2 accumulation in skeletal muscles. The higher K+-absorbing/K_ secreting mechanisms ratio in younger rats contributes to the positive potassium balance.

Adenosine Triphosphatases↗
PubMed1993

[The effects of enkephalins on the water-salt metabolism of rats in ontogeny].

The experiments were carried out in white Wistar rats of three ages: 25-30 days (Group 1, n = 102), 45-50 days (group 2, n = 62), over 180 days (group 3, n = 115). The water loading was given through a gastric tube in an amount of 5% of the body weight. A synthetic analogue of leu-enkephalin (SAE) was injected intraperitoneally in a dose of 100 mg/kg. The control animals received physiological saline. In the baby rats of group 1, administration of SAE slowed down the polyuric and ionouretic reactions in response to the water loading. In older rats of group 2 administration of SAE enhanced water elimination but with this the osmolarity of the blood plasma increased together with the content of potassium and sodium ions in it. In adult rats (group 3) injections of SAE produced a smooth diuretic reaction which retained constant ion levels in the blood plasma.

Aging↗
PubMed1990

[Structural and functional status of the kidneys in children with nephropathies associated with metabolic disorders].

A total of 365 children aged 1 to 16 years were examined. The dimensions of the kidneys are given in health and in nephropathies associated with metabolic disorders. Echography made it possible to identify the presence of salt crystals in the pelves. The tension of osmoregulating renal function in response to water loading manifested by the reduction of the degree of osmotic dilution and the rise of ion excretion was established. One of the reasons for such alterations is plasma hyperosmia that is likely to be conditioned by the rise of salt concentrations in the blood. The functional changes seen in the kidneys were found to depend on the age.

Adolescent↗
PubMed1984

[Characteristics of the sodium storage capability of the liver].

It has been shown in acute experiments on cats and dogs that the liver is an effective barrier preventing the increase of sodium concentration in systemic circulation. As demonstrated by calculations, the reduction of sodium concentration shifts was not the consequence of portal vein blood dilution with the blood delivered by the hepatic artery. The total amount of sodium accumulated by the liver depended on basal liver sodium content.

Animals↗
PubMed1980

[Integration of mechanisms regulating water-salt equilibrium during increasing water, salt, and volume loading].

The mechanism of integration of osmo- and volume-regulating systems after intake of 3, 5, 7, and 10% of body weight water, salt, and volume loads, was studied in adult rats. The changes of diuretic and ionuretic renal functions depended on the character and quantity of shifts caused in organism. The volume shift is the starting mechanism for stabilization of disturbed balance while the osmotic factor secures the final regulation of watersalt homeostasis.

Animals↗
PubMed1976

[Osmo- and ionic liver receptors].

Role of the liver receptors in osmo- and ionic homeostasis regulation was studied in unanesthetized dogs. The presence of selective sodium-and potassium-sensitive receptors was shown in the liver receptor field. Stimulation of the ionic receptors evokes ADH-induced antidiuretic and specific ionuretic renal response. Impulses depressing diuresis were found to spread mainly in the posterior roots of the spinal cord, while those changing the ion excretion - in the n. vagi.

Animals↗