[Identification of histochrome metabolism products in urine for studying drug pharmacokinetics].

Histochrome is the medicinal form of echinochrome (2,3,5,6,8-pentahydroxy-7-ethyl-1,4-naphthoquinone). The drug pharmacodynamics and its relationship with metabolism, which was revealed in previous investigations, predetermined the aim of this work: to study excretion of echinochrome and its possible metabolites in urine of rats. Histochrome was introduced to Wistar rats (n = 10) subcutaneously in a dose of 10 mg/kg. Naphthoquinone derivatives were extracted from the acidified urine by ethyl acetate and analyzed by high performance liquid chromatography with UV detection (HPLC/UV) and mass-spectrometric detection (HPLC/MS). It was established that histochrome is completely metabolized in an organism and excreted by kidneys in the form of 3-methoxy-2,5,6,8-tetrahydroxy-7-ethyl-1,4-naphthoquinone and 2-metoxy-3,5,6,8-tetrahydroxy-7-ethyl-1,4-naphthoquinone.

[Anti-lithogenic effect of meloxicam in experimental nephrolithiasis].

Experiments performed on 23 male rats, were divided into 2 groups. Animals in the control received group 1% solution of ethylene glycol (EG) as a drink during 6 weeks. In the test group, EG was also introduced for 6 weeks, and meloxicam was administered in a dose of 2.5 mg/kg from the 4th week. Every 7 days, daily urine was analyzed for the concentrations of oxalate, phosphate, and calcium and for the activity of urothelium injury marker enzymes includng lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), and N-acetyl-beta-D-glucose aminidase (NAG). In addition, sections of the rats kidney were used to detect calcium deposits by histochemical Van Koss method. The treatment of experimental nephrolithiasis by meloxicame led to simplification of pathology, as indicated by a significant reduction in the urine oxalate and calcium concentrations and a pronounced decrease in the activity of all marker enzymes (LDH, GGT, NAG).This was confirmed by morphological studies, which detected very significant reduction in both number and size of calcium deposits.

[Effects of water drinking regimens on crystallization intensity in experimental nephrolithiasis].

We studied effects of water regimens on crystallization efficacy in experimental nephrolithiasis on 3 groups of Wistar male rats with initial experimental nephrolithiasis (ethylene glycol model). The animals were on free, limited and supernormal liquid intake regimen. For 3 weeks each 3-4 days we estimated 24-h diuresis, urine concentration of calcium, phosphate and oxalate ions. After 3 weeks we made a morphological examination of the kidneys. We found that limited drinking leads to an increase in urinary concentrations of oxalate- and phosphate ions which stimulate enhanced formation of calcium-containing concrements. More water intake considerably reduces oxalate and phosphate concentrations in the urine resulting in reduction of the number and size of calcium deposits in renal tissue. Thus, low liquid intake leads to intensification of urine oversaturation causing formation of renal concrements. Much liquid intake weakens oversaturation and reduces the number and size of calcium deposits in the kidneys.

[A new technique for urinary oxalate ion determination].

The authors propose a technique for the determination of urinary oxalate ions by high performance liquid chromatography, which may be used for clinical and scientific purposes.

[Modified method for the demonstration of argyrophilic proteins in the nucleolar organizer regions in paraffin sections].

The modified method of staining of argyrophilic nucleolar organizer regions (AgNORs) by silver nitrate is presented. This modification eliminates some disadvantages of an original technique. The method accelerates staining and prevents the precipitation of deposits.

[Features of the pharmacodynamics and pharmacokinetics of furosemide upon long-term administration in rats].

Long-term administration of furosemide in rats (single daily dose, 20 mg/kg for 7 days) was accompanied by a decrease in the diuretic, natriuretic, and kaliuretic effects, which was related to a decrease in the rate of renal metabolism and excretion. It was found that more than 85% of the daily excretion of sodium takes place within the first 6 h after furosemide administration (on the background of comparable excretion of the drug), while the elimination of potassium and water during one day is more uniform. It is established that the long-term administration of furosemide leads to a decrease in the drug excretion during the first 6-h period, followed by a growth in the subsequent 18-h period of time. These changes in the daily dynamics of drug excretion account for the analogous trends in the elimination of water and electrolytes.

[The chemico-pharmacological patterns in the action of plants from the family of Pyrolaceae]. / Khimiko-farmakologicheskie zakonomernosti v deistvii semeistva grushankovykh.

The effect of leaf decoctions of three plants of the Pyrolaceae family, namely, umbrella wintergreen, one-side ortilia, and round-leaf Pyrola was studied in rat experiments. All plants under study were found to contain approximately equal amounts of tannins and arbutin glycoside. Their concentration was comparable though rather lower than in common bearberry, a well-known plant with diuretic and antiseptic activity. When given for a long time, all Pyrolaceae increased urination and sodium excretion. Besides, their decoctions caused an antimicrobial effect. Only round-leaf Pyrola weakened the development of experimental inflammation. Its anti-inflammatory effect was probably due the presence of flavonoids the content of which in Pyrola was maximum.

[The effect of calcium antagonists on the development of inflammatory edema in rats]. / Vliianie antagonistov kal'tsiia na razvitie vospalitel'nogo oteka u krys.

The calcium antagonists verapamil and nifedipine were shown to attenuate the development of carrageenin-induced rat paw inflammatory edema. Oral nifedipine exerted more pronounced antiedematous dose-dependent effects.

[Method of determining kidney tubular secretion with verografin in rats in chronic trials]. / Sposob opredeleniia kanal'tsevoi sekretsii pochek po verografinu u krys v khronicheskikh opytakh.

A simple method for evaluation of the renal tubular excretion in rats by verografin after a single intraperitoneal injection in combination with inulin is proposed.

[Role of insulin in the regulation of the tubular reabsorption of glucose in the kidneys]. / Znachenie insulina v reguliatsii kanal'tsevoi reabsorbtsii gliukozy v pochkakh.

Glucose tubular transport in the kidneys in changes of insulin concentration in the blood was studied in acute and chronic experiments on dogs. Maximum glucose reabsorption in the kidneys was shown to remain unchanged in the stimulation of insulin secretion or depletion of insular function (alloxan diabetes). Neither did the administration of insulin into the renal artery at doses of 0.02-0.04 U/min for 30 min. influence glucose reabsorption which rose during hormone infusion at doses of 0.4-0.5 U/min only.

[Effect of dopamine on transport of organic substances in dog kidneys]. / Vliianie dofamina na transport organicheskikh veshchestv v pochkakh sobak.

I. v. infusion of dopamine increased diuresis, glomerular filtration rate, maximal reabsorption of glucose and tubular secretion of cardiotrast. Infusion of dopamine into the renal artery did not affect glomerular filtration rate and tubular secretion of cardiotrast while maximal reabsorption rate of glucose was increased. Dopamine exerted some direct effect on the transport of glucose, which effect can be blocked with haloperidol.

[Ultrastructure of proximal tubular cells of the rat nephron in the period of intense glucose reabsorption]. / Ul'trastruktura kletok proksimal'nogo kanal'tsanefronakrysy v period intensivnoi reabsorbtsii gliukozy.

It has been demonstrated in rat experiment that maximal glucose reabsorption is accompanied by the increased electron density of mitochondrial matrix and the enlargement of the size of microbodies. No vacuoles have been recorded, which is at variance with the concept of the pinocytosis involvement into glucose reabsorption.