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Biomedical subjects

Y V Natochin

Publications and source records attributed to Y V Natochin.

At least 19 recordsLinked to original sources
PubMed2000

Nocturnal enuresis: correction of renal function by desmopressin and diclofenac.

Sixty-two children with nocturnal enuresis (43 boys, 19 girls aged 6-15 years) were treated with either desmopressin (Adiuretin-SD) (n = 32) or sodium diclofenac (n = 30). Desmopressin was effective in 85% of children and diclofenac in 33%. In children with primary nocturnal enuresis, the glomerular filtration rate was normal, whereas diuresis and solute excretion during the night were increased. Compared with healthy children, the nightly excretion of sodium was elevated by 43.7% and magnesium by 58.4%. A high correlation was found between the free water reabsorption and solute clearance (P < 0.001) in children with nocturnal enuresis. Changes in kidney function in nocturnal enuresis appear to be due to a decrease in the water and ion reabsorption in the thick ascending limb of Henle's loop because of a changed regulation of ion transport in this part of the nephron. Administration of desmopressin or a decrease in prostaglandin production after diclofenac administration restores the ion and water transport in the kidney, which results in the disappearance of nocturnal enuresis. The results indicate a role of changes in regulation of ion transport in renal tubules in the pathogenesis of one of the forms of primary nocturnal enuresis.

Adolescent↗
PubMed2000

Possible role of prostaglandins in pathogenesis of nocturnal enuresis in children.

OBJECTIVE: To compare excretion of ions and prostaglandins by the kidney in children with noctural enuresis. MATERIAL AND METHODS: Thirty-two children with primary nocturnal enuresis and 23 normal children were examined. Osmolality and sodium and potassium concentrations were measured in their urine and blood serum. Prostaglandins E2, E1, and F2alpha were determined using kits for immunoenzyme analysis. Luminal and contraluminal prostaglandin secretions were studied in frog urinary bladder. RESULTS: Children with nocturnal enuresis have increased nocturnal diuresis and renal sodium excretion, but no increase was found in excretion of prostaglandins E2, E1, and F2alpha. Administration of sodium diclofenac before bed-time eliminated episodes of nocturnal enuresis in 37% of children; intranasal administration of Adiuretin SD had a positive effect in 69% of enuretics. In children with nocturnal enuresis there is a correlation between renal excretion of PGE2 and sodium ions; this correlation is absent in the control group children, and disappears in enuretics treated with desmopressin. To evaluate the representativeness of the data on prostaglandin secretions to urine as compared with their release to extracellular fluid, experiments on frog urinary bladder were performed: a correlation was found between prostaglandin secretion to the urinary bladder lumen and to the extracellular fluid. CONCLUSIONS: The results of the study suggest that changes in renal function are due not to a higher secretion of prostaglandins in nocturnal enuresis but to the relative dominance of their effect as compared with other physiologically active substances that simultaneously act on renal tubular cells.

Adolescent↗
PubMed2000

Study of the role of prostaglandin E2 in urine flow regulation in chronic renal failure.

OBJECTIVE: This study was carried out to investigate the role of prostaglandin E2 in the regulation of urine flow and ion excretion in patients with chronic renal failure. MATERIAL AND METHODS: Twenty patients with chronic renal failure (CRF) and 13 healthy people were studied. CRF develops as a terminal stage of glomerulonephritis, pyelonephritis or polycystic renal disease. Osmolality and sodium, potassium, magnesium, calcium and creatinine concentrations were measured in urine and blood serum. Urine prostaglandin E2 was determined using kits for imminoenzyme analysis. RESULTS: The average creatinine clearance was 19.9 +/- 6.3 ml/min, but it varied from 30 to 10 ml/min in different patients. In patients with CRF a correlation was revealed between diuresis and Na excretion (r = 0.78, p < 0.001) and between Na excretion and PGE2 excretion (r = 0.65, p < 0.001), a correlation that lacking in the healthy subject. A correlation was also found between diuresis and Mg excretion (r = 0.68, p < 0.001) and between Mg excretion and Na excretion (r = 0.83, p < 0.001) in patients with CRF but not in healthy subject. CONCLUSION: It is suggested that in patients with CRF who experience a decrease in the glomerular filtration rate (to 75-90% of the normal value) the increase in urine flow is due to prostaglandin-dependent inhibition of ion reabsorption in the thick ascending limb of the loop of Henle.

Dinoprostone↗
PubMed1999

Defect of osmoregulatory renal function in nocturnal enuresis.

Renal function was studied in 62 children with primary nocturnal enuresis (PNE) and in 20 healthy children aged 6-15 years. During the night, children with PNE exhibited an increase in diuresis, free water reabsorption and solute excretion (including sodium and magnesium) in comparison to controls. Intranasal administration of Adiuretin-SD (10.5-24.5 micrograms) in the evening reduced diuresis and ion excretion to normal levels. During the treatment, 61% of the children became completely dry and, in 24% of the children, the number of wet nights was reduced by 50%. It is suggested that in the pathogenesis of PNE, the decrease in ion reabsorption in the thick ascending Henle's loop--resulting in a greater load of tubular fluid in the collecting ducts, an elevation of diuresis and increases in free water reabsorption and solute excretion--plays the leading role in disturbing renal function. Treatment of PNE with desmopressin is pathogenically justified, as it eliminates the principal defect of renal tubular function.

Administration, Intranasal↗
PubMed1998

Ultrastructural correlates of the antidiuretic hormone-dependent and antidiuretic hormone-independent increase of osmotic water permeability in the frog urinary bladder epithelium.

Electron and confocal microscopy, using immunocytochemical methods, was employed to assess osmotic water permeability of the frog (Rana temporaria) urinary bladder during transcellular water transport, induced by antidiuretic hormone (ADH) or by wash-out of autacoids from serosal, ADH-free Ringer solution. The increase of osmotic water permeability of the urinary bladder was accompanied by relevant ultrastructural changes, the most remarkable being: (1) the appearance of aggregates of intramembranous particles in the apical membrane of granular cells, and the extent of the membrane area covered by the aggregates proportional to that of the water flow; (2) redistribution of actin filaments in the cytoplasm of granular cells; judging from the anti-actin label density, the number of actin filaments in the apical region of cytoplasm was reduced by 2.5-4 times compared with normal; (3) a decrease in the total electron density of the cytoplasm due to the increased water content of granular cells.

Actins↗
PubMed1998

Osmoregulatory function of the kidney in enuretic children.

Twenty children with primary nocturnal enuresis and 20 healthy children of the same age and sex were studied. Natural urination was used for the 24-h urine collection. It was found that urine osmolality and free water reabsorption during the night did not differ statistically significantly between the enuretic children and the healthy. The increased diuresis in the enuretic children was caused by a higher excretion of the osmotically active solutes, including sodium. Use of desmopressin reduced diuresis and natriuresis to normal levels. It is suggested that the main role in the pathogenesis of the studied form of nocturnal enuresis is played by a decrease in ion reabsorption, probably in the thick ascending Henle loop, which facilitates the increase in diuresis and occurrence of nocturnal enuresis.

Adolescent↗
PubMed1997

Role of prostaglandin E2 in regulation of low and high water osmotic permeability in frog urinary bladder.

The water osmotic permeability of frog urinary bladder was found to be increased from 0.08 +/- 0.01 to 1.28 +/- 0.20 microl/min cm2 when serosal bathing medium was changed 4 times for a fresh Ringer solution. High epithelium permeability is accompanied by an increased content of cyclic AMP in the bladder tissue (by 42%, P < 0.01), higher activity of both basal and forskolin-stimulated membrane adenylate cyclase (AC) (by 109% and 74%, respectively, P < 0.05) and by appearance of aggregates of intramembranous particles in the apical membrane. The water flow was inhibited by 10(-9)-10(-5) M prostaglandin E2 (PGE2); the inhibitory effect was eliminated in the presence of 10(-4) M N-ethylmaleimide. The increase of water permeability due to changes of the bathing medium was accompanied by a decrease of serosal PGE2 concentration from 14.8 +/- 1.0 in the 1st solution to 0.6 +/- 0.1 nM in the 5th. 10(-6) M PGE2 in vitro inhibited the activity of membrane AC from highly permeable bladders by 33.4% (P < 0.02). Pretreatment of the membranes with 10 microg/ml pertussis toxin (PT) completely reversed this effect (+149%, P < 0.01). A significant activation of AC was also observed under 10(-10) M PGE2 (by 196%). These data demonstrate that the water permeability could be markedly increased independently of ADH, suggesting that the trigger role in activation of water transport is played by a decreased level of PGE2 which could stimulate AC.

Adenylate Cyclase Toxin↗
PubMed1996

Development of the hypothalamic vasopressin system and nephrons in Meriones shawi during ontogenesis.

This study has evaluated the development of the hypothalamic vasopressin system and nephrons of the kidney in desert rodents, Meriones shawi, which effectively retain water by excretion of highly concentrated urine. The vasopressin system was studied immunocytochemically at the 18th fetal day, at the 2nd, 13th, 27th postnatal days and in adulthood. The kidneys were investigated at the 2nd, 13th postnatal days and in adulthood using microdissection technique. Occasional vasopressin-immunoreactive neurons were observed as early as the 18th fetal day, only in the paraventricular nucleus. From the 2nd postnatal day onwards, vasopressin neurons increased progressively in number, being mainly concentrated in the supraoptic and paraventricular nuclei, as well as in the ventral retrochiasmatic region. Transient neuronal populations were also observed at the 13th postnatal day in the lateral preoptic area and anterior hypothalamic nucleus. Apart from the neurons, the glandular cells of the tuberal lobe showed immunostaining from the 18th fetal day, the first age studied, until the 13th postnatal day. The fibers of differentiating vasopressin neurons grew towards the circumventricular/neurohemal organs, terminating in the organum vasculosum of the lamina terminalis and the lateral ventricles as early as the 18th fetal day, as well as the third ventricle, the posterior lobe and the external zone of the median eminence between the 2nd and 13th postnatal days. The kidney in 2-day-old Meriones comprised nephrons at different stages of development from an S-shaped body to well-differentiated nephrons. At the 13th postnatal day, as in adulthood, the nephrons were well differentiated and characterized by long, thin loops descending to different levels of papilla. Thus, according to our morphological data the hypothalamic vasopressin neurons and nephrons in the kidney of Meriones reach the definitive state by the end of the 2nd postnatal week.

Aging↗
PubMed1996

Evolutionary aspects of renal function.

In his hypothesis of the evolution of renal functions Homer Smith proposed that the formation of glomerular nephron and body armor had been adequate for the appearance of primitive vertebrates in fresh water and that the adaptation of homoiotherms to terrestrial life was accompanied by the appearance of the loop of Henle. In the current paper, the increase in the arterial blood supply and glomerular filtration rate and the sharp elevation of the proximal reabsorption are viewed as important mechanisms in the evolution of the kidney. The presence of glomeruli in myxines and of nephron loops in lampreys suggests that fresh water animals used the preformed glomerular apparatus of early vertebrates, while mechanisms of urinary concentration was associated with the subdivision of the kidney into the renal cortex and medulla. The principles of evolution of renal functions can be observed at several levels of organizations in the kidney.

Animals↗
PubMed1995

Modulation of the effect of arginine-vasopressin on water and ion transport in the newt early distal tubule and frog urinary bladder by V1-antagonists.

In the early distal tubule of the newt Triturus vulgaris L., 1 nM arginine-vasopressin (AVP) increased water reabsorption; the fractional reabsorption of Na+ was elevated from 46.2 +/- 6.9% to 67.8 +/- 3.9% (P < 0.001), of Cl- from 52.7 +/- 6.7% to 73.1 +/- 3.5% (P < 0.001), of Mg2+ from 48.0 +/- 7.7% to 71.7 +/- 6.3% (P < 0.001). When V1-receptors were blocked by 1 nM peptide V1-antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl) Tyr]-[Arg8]vasopressin, 1 nM AVP increased the fractional reabsorption of fluid by 8.9% of Na+ by 10.7% and of Cl- by 11.2%, as compared with the effect of AVP alone. The fractional reabsorption of Ca2+ after addition of AVP did not differ from control; when V1-receptors were blocked in the presence of AVP, the fractional reabsorption of Ca2+ was increased by AVP. The V1-receptor block in the presence of AVP did not change the fractional reabsorption of Mg2+. Experiments on the urinary bladder of the frog Rana temporaria L. showed that 1 nM SR 49059, a non-peptide antagonist of V1a-receptors, like the peptide V1-antagonist, enhanced the AVP effect by 29%. Inhibition of protein kinase C activity by calphostin C (1 nM) mimicked the effect of V1-antagonists; the AVP hydroosmotic effect was increased by 60%. The results obtained indicate that V1-receptors modulate the effects of V2-receptor activation: their block is accompanied by an enhancement of the AVP hydroosmotic effect in the frog urinary bladder and by an increase of Na+ and Cl- reabsorption in the newt early distal tubule. The enhancement of the AVP effect owing to the V1-receptor activation seems to be mediated by a decrease in protein kinase C activity.

Animals↗
PubMed1994

Renal failure and nephrotoxic drug-induced disturbances in rat kidney tissue.

The injection to rats of glycerol, cisplatin, uranyl acetate, sodium dichromate, and mercuric chloride is followed on the third day by acute renal failure. A new approach for quantitative estimation of disturbance of excretory renal function is presented. The decrease in renal function due to uranyl acetate was 77%; sodium dichromate, 71%; mercuric chloride, 52%; cisplatin, 25%; and glycerol, 10%. The kidneys still maintained serum ion concentration close to normal values. Injection of nephrotoxic drugs increased kidney wet weight by 24-57%. This was caused by swelling of renal tissue and increases in dry weight of the kidneys. The sodium content increased in the renal cortex and decreased in the papilla. The potassium content of the renal cortex is increased. The effect of some nephrotoxic drugs is suggested to depend on an increased number of cells in the renal cortex (probably due to hemostasis and inflammation) and a decrease of renal medulla function. The above drugs induce disturbance of kidney tissue but have no effect on the ion and water content in liver and m. gastrocnemius.

Acute Kidney Injury↗
PubMed1993

Renal function and renal platinum content in uninephrectomized rats following cisplatin administration.

The changes in renal function and renal platinum content were assessed in uninephrectomized and sham-operated female Wistar rats on the third day after treatment with 2.5 mg/kg BW or 5 mg/kg BW cisplatin. Treatment of control and nephrectomized rats with 2.5 mg/kg BW cisplatin resulted in indices of renal function which were not significantly different from those of animals which had received no cisplatin, though the renal platinum contents in nephrectomized rats were practically the same as in two-kidney animals given 5 mg/kg BW cisplatin. Treatment with 5 mg/kg cisplatin resulted in much less severe changes in kidney weight and renal function compared to two-kidney animals, in spite of much more substantial (by 49-58%) platinum accumulation.

Animals↗
PubMed1992

Chelating agent reversal of cadmium effects on ionic transport in the isolated frog skin (Rana temporaria).

1. The application of 1 mM CdCl2 to the outside surface of frog skin causes a large increase in the potential difference (PD) across the skin and in the short-circuit current (SCC); the subsequent addition of selected dithiocarbamate chelating agents (which by themselves have no effect on PD or SCC) restored both electrical parameters to values close to initial levels. 2. The response observed on addition of the chelating agents indicates that the effect of CdCl2 is reversible and that the complexed ions do not possess the ability to initiate corresponding changes in the transepithelial ion transport processes in the frog skin.

Animals↗
PubMed1991

The prevention of cisplatin-induced renal dysfunction by hydroxyl-containing dithiocarbamates.

Two hydroxyl containing dithiocarbamates, sodium N-methyl-D-glucamine dithiocarbamate (NaG) and sodium dihydroxyethyl dithiocarbamate (NaY) have been examined as agents for the control of the renal dysfunction in rats given cisplatin. Of these, NaG was found to be the more effective in controlling such renal dysfunction when administered at 1 and 3 h after 5 mg cisplatin kg-1, i.p. Renal function was examined 5 days after the administration of cisplatin by measurement of serum and urinary levels of creatinine and urea, creatinine clearance, serum and urinary levels of Na+, K+, Mg2+, Ca2+, as well as the concentrations of these ions in the renal medulla and cortex. Treatment of rats given cisplatin with NaG at 1 and 3 h post cisplatin resulted in indices of renal function which were not significantly different from those of animals which had received no cisplatin. The sole difference was found to be a slight increase in renal cortical Na+ concentration.

Animals↗
PubMed1985

Features of osmotic and ionic regulations in Russian sturgeon (Acipenser güldenstädti Brandt).

The osmolality of blood serum of one group of Russian sturgeon fished out in Southern Caspian Sea was the same as their habitat, the other group of sturgeons had a serum osmolality several per cent lower than that of sea-water in this part of the Caspian Sea. Ion concentrations in blood serum in sturgens were similar in fresh water and the Caspian Sea. The feature of the Russian sturgeon's kidney is intensive potassium secretion and a comparatively low level of magnesium secretion.

Animals↗
PubMed1981

Structural and chemical features of the invertebrate otoliths.

In the course of evolution of the invertebrate gravity receptor endogenous intracellular mode of the otoliths formation (Coelenterata, Ctenophora) is changed for endogenous extracellular mode (Mollusca, Arthropoda). The intracellular otolith is represented by cristalline concretions whereas extracellular one may consists of many separate crystallic otoconia or one large spherolith. As a rule in all cases qualitative mineral composition is similar. Calcium is the main component of the otolith in invertebrates (as vertebrates) though magnesium, sodium and potassium also take place in the otolith formation.

Acoustic Maculae↗
PubMed1979

Succinate dehydrogenase activity in rat kidney after repeated administrations of p-aminohippurate or sodium chloride.

During PAH excretion and 18 h after repeated PAH administrations to rats, renal cortical SDH activity was unchanged in comparison with untreated controls. On the other hand, 18 h after repeated administrations of 0.9% or 1.8% NaCl solution, SDH activity was decreased by about 20% in kidney cortex. In outer medulla SDH activity was decreased 18 h after all pretreatments. The decline of SDH activity was observed whenever an increased urinary Na excretion occurred, except that PAH was repeatedly administered. The probability is discussed that substrate-induced stimulation of the carrier system for weak organic acids is accompanied by an increase of mitochondrial activity in kidney cortex.

Aminohippuric Acids↗