Pathomorphological picture of the liver in mice administered antitumor antibiotics intraperitoneally and its comparative assessment]

A single administration of carminomycin, ribomycin or olivomycin in LD50 or treatment of the experimental animals with these antibiotics for 10 days in the therapeutic doses equal to 10 per cent of the LD50 induced distrophic and necrobiotic changes in the liver. The use of bruneomycin in the equivalent doses induced sclerotic process in addition to the above doses resulted in a decrease in the colour intensity of DNA, RNA and protein as compared to the control, the content of glycogen and a marked increase in the amount of lipids in the hepatocyte cytoplasm. The most pronounced shifts were observed with the use of carminomycin, rubomycin and especially bruneomycin in single doses. With the use of olivomycin in a single dose the shifts were less pronounced. It should be noted that with the use of carminomycin and rubomycin the damages were of the same character by their intensity. The changes in the liver on the use of carminomycin, rubomycin and olivomycin in single doses or during the treatment course were reversible, while on the use of bruneomycin they preserved to the end of the experiment.     

Discovery of early urinary biomarkers in preclinical study of gentamicin-induced kidney injury and recovery in rats

LC/MS- and NMR-based global metabolomics analyses were utilized to study the changes in rat urine in response to gentamicin treatment. Sprague?CDawley rats were dosed with gentamicin sulfate at 0, 75, 150 or 300?mg/kg/day for one, two or three consecutive days. Four animals from each group were sacrificed to harvest kidney tissue and to collect urine on days 1, 2, 3, 7, 10, 15, 18, 22, 29, 36 and 44 for a total of 11 different time points. Both uni- and multivariate statistical analyses were employed to identify the significantly changed metabolites in urine at the different dose levels and time points. Increases and decreases in amino acids including tyrosine, valine and hydroxyproline reflected histopathology changes of kidney injury development and/or kidney injury recovery. Glucosuria was noted much earlier than changes in the classic kidney function biomarkers, blood urea nitrogen and serum creatinine. Dopamine-related compounds, homovanillic acid sulfate (HVA-SO₄) and homoveratric acid sulfate (HVrA-SO₄) were significantly increased at early time points and could be early indicators of a renal adaptive response to gentamicin-induced renal injury. Furthermore, the drug efficacy of gentamicin was evaluated through the detection of changes in gut microflora-related compounds (e.g. indole-containing metabolites). Metabolomics was successful in identifying valine, hydroxyproline, HVA-SO₄ and HVrA-SO₄ that might serve as potential early injury biomarkers or adaptive markers of gentamicin-induced renal injury, and in assessing gentamicin efficacy through changes in compounds reported to be related to gut microflora. However, caution should be taken in direct translation of the biomarkers reported in clinical settings because a much higher dose of gentamicin than the normal therapeutic dose (~1?C2?mg/kg) was used to cause kidney damaged.     

Experimental study of the organotropic properties of dactinomycin

Dactinomycin was studied pharmacologically on experimental animals. When dactinomycin was administered to the test-animals in doses close to the therapeutic ones for humans, suppression of the bone marrow blood formation was registered in spite of some increase in the number of the reticulocytes and thrombocytes in the peripheral blood and acceleration of the process of blood coagulation. In addition, the urea nitrogen blood levels increased. When the drug was administered in higher doses, suppression of the bone marrow blood formation was pronounced and the number of the leucocytes, reticulocytes and thrombocytes in the peripheral blood decreased. The rate of the blood coagulation decreased, while the biochemical values of the blood were indicative of impairement of the liver and kidney functions.     

Effect of chronic alcoholic intoxication in the rat on the structural organization of the caudate nucleus in their progeny

By means of light (Nissl and Golgi), electron microscopy, as well as using morphometry, structure of neurons and interneuronal connections of the nucleus caudatus has been studied in 21-day-old rats reproduced by chronically alcoholized parents. As demonstrated the investigations, in young rats, physically underdeveloped, there are some signs of a delayed maturation in neurons, dendrites and synapses. Certain distrophic and reparative shifts are observed in all experimental animals. The distrophic changes of neural structures in the nucleus caudatus preponderate over the reparative ones, and in the destructive course not only the neuronal body is involved, but its processes, as well. The lesions of the latter influence organization of the synaptic contacts. This is demonstrated as a sharply decreased number of synapses of the formation studied in the field of vision. The occurring disturbance in the structure of dendrites, which play an important role in the primary integration of the information received by the neuron, can cause development of certain mental disorders in children born in alcoholic families. The reparative changes in neurons and interneuronal connections revealed suppose possible reversibility of the morphological changes observed in the offspring of drunkards.     

Experimental study of the organotropic side-effect properties of polymyxin B]

Toxicity of Soviet polymyxin B and its effect on the central peripheral nervous system, blood circulation, respiration, smooth muscles, functional liver and kidney state, growth and development of young animals, the picture of the peripheral blood were studied in acute and chronic experiments on various species of animals. It was found that polymyxin B had a suppressing effect on the peripheral n-cholinoreactive systems of the neuromuscle synapses of the skeletal muscles and ganglia of the sympathic and parasympathic innervation and deprimizing effect on the central nervous system. Caffeine, adrenaline and calcium chloride proved to be the antagonists of the neurotoxic effects of polymyxin B. The chronic experiments revealed that polymyxin B induced disorders in the kidney function and morphological changes in the glomeruli after its repeated administration. No significant effect of polymyxin B on the growth and development of the young animals, the functional state of the liver and the picture of the peripheral blood was observed when the drug was used in doses corresponding to the therapeutic ones in clinics.     

An experimental study of acute and chronic effects of phenacetin on the rat kidney, using clinical-chemical and biochemical methods.

In rats, changes in urinary enzymatic activities (AP, SP, LAP, beta-GLU, MUR) were recorded following the administration of phenacetin in acute doses (4.75 and 7.15 mmol/kg). Urinary AP and LAP activities were measured over 77 days in which 3.35 mmol phenacetin/kg were given daily. The results revealed immediate and delayed effects of phenacetin, depending upon the quality of the drug used. In the chronic series, changes in urinary enzymatic activities were less pronounced. Concomitant biochemical investigations of kidney cell fractions revealed the occurrence of mitochondrial damage under the influence of chronic phenacetin administration. Following acute doses of phenacetin, destructive alterations in the plasma membrane of kidney cells were encountered. Investigations of serum enzymatic activities 24 h after phenacetin administration did not reveal any significant changes.     

Simulation of the pharmacokinetics of aminoglycosides in the kidneys: single and continuous intake of sisomicin and gentamicin by rats

The pharmacokinetics of sisomicin and gentamicin in the cortical and medullary layers of the kidneys was studied on rats. The antibiotics were administered daily in doses of 12.5 and 25 mg/kg a day. The levels of the antibiotics in the cortical layer were much higher than those in the medullary layer. The use of a twice as higher dose in the first case resulted in a less than a two-fold increase in the drug concentration, while in the second case the increase was more than two-fold. Prognosis of the pharmacokinetics of aminoglycosides used for 8-16 days was achieved with the help of the constants of the two-compartmental model. It was shown that the actual levels of sisomicin and gentamicin in the kidney medullary layer did not significantly differ from the estimated ones and the levels of the drugs in the cortical layer were much lower than the predicted ones. The distorted linearity of the aminoglycoside pharmacokinetics must be mainly due to saturation of the cortical layer with the drugs.     

Influence of Feeding Schedule on Chronopharmacological Aspects of Gentamicin in Mice

The effects of the time of day of drug administration on the subchronic toxicity and pharmacokinetics of gentamicin, as well as the role of feeding schedule on circadian rhythms, were investigated in mice. ICR male mice were housed in a light-dark (LD) cycle (12:12) with food and water ad libitum (ALF) or under a time-restricted feeding (TRF) schedule (feeding time: 8 h during the light phase) for 1 day or 14 days before drug administration. The animals were given a single subcutaneous dose of gentamicin 180 mg/kg for the kinetic studies and subcutaneous doses of gentamicin 180 mg/kg/day for 14 days or 220 mg/kg/day for 18 days for the subchronic toxicity studies. A significant dosing-time dependency was shown for mortality and body weight loss, with higher values at midlight and lower ones at the middark (p > 0.05). A significant circadian rhythm was also found for gentamicin kinetics in ALF mice, with the highest clearance at middark and the lowest one at midlight (p > 0.01). The kinetic rhythm of gentamicin coincided well with the toxicity rhythm of the drug. The TRF schedule had a marked influence on the rhythms of gentamicin kinetics and toxicity, showing lowest clearance and higher toxicity at middark. The rhythm of subchronic toxicity of gentamicin seems to be due, at least in part, to the rhythm in kinetics and is strongly influenced by the feeding schedule. Thus, the timing of dosing is an important factor in the kinetics and the subchronic toxicity of gentamicin administration in mice, and the manipulation of feeding schedule can modify the rhythm of the toxicity by changing the rhythm of gentamicin kinetics.     

Study of the pharmacological properties and safety of a solution of levomycetin in hexamethylene tetramine for intravenous administration]

Pharmacological properties of 2 per cent levomycetin solution in 40 percent hexamethylentetramine solution, as a new pharmaceutical form of levomycetin for intravenous administration prepared at drug-stores were studied. The maximum tolerating doses of the drug for mice, rabbits, and dogs were 26-47 times higher than the therapeutic ones with respect to the content of levomycetin and hexamethylentetramine. No increase in the toxicity of levomycetin and hexamethylentetramine in the preparation was observed. The drug in the doses 16 times higher than the therapeutic ones by the content of levomycetin did not almost change the arterial pressure and the drug in the doses 3.7 times higher than the therapeutic ones did not affect the blood coagulation either in acute experiments, or on its prolong intravenous infusion. Repeated administrations of the drug to rats and rabbits for 15-18 days in doses 3.7-4.8 times higher than the therapeutic ones by the content of levomycetin were innocuous for the animals. Absorption, circulation in the blood, distribution in the tissues and excretion with the urine of levomycetin used in the above pharmaceutical form did not differ from circulation of the antibiotic on its intravenous and oral administration. The drug is recommended for use in medical practice.     

Experimental data on hygienic norms for antibiotics of the tetracycline group]

Toxicity of tetracyclines was studied experimentally on different species of laboratory animals. It was shown that tetracycline, oxytetracycline and chlortetracycline were close by their chemical structure and physico-chemical properties, as well as by the main toxicity parameters, i.e. acute toxicity, cumulative activity, skin-irritating and sensitizing effect. Under the conditions of subacute experiments the above 3 antibiotics induced evenly pronounced one direction changes in animals. The data obtained during the experiments provided recommendation of the level of 0.1 mg/m3 as the maximum allowable concentration (MAC) of oxytetracycline and chlortetracycline, i.e. the same level as the previously recommended for tetracycline.     

Developmental characteristics of the inferior tracheobronchial and mesenteric lymph nodes in exposure to tetracycline hydrochloride

Development of the tracheobronchial and mesenteric lymph nodes has been studied in fetuses and offsprings of Wistar rats after an intramuscular administration to the female rats therapeutic doses of tetracycline hydrochloride during the first 6 days of pregnancy (preimplantation period of embryogenesis). General histological and morphometrical methods have been applied. Under the experimental conditions certain disorders in formation of functional structures of the lymph nodes have been revealed: differentiation of the parenchyma into the cortical and medullary substance formation of follicles and their germinative centers, development of sinuses, formation of argyrophile stroma architectonics are delayed. Some distrophic and destructive changes of the reticular cells are observed, argyrophilia of the reticular fibers is more evident. Lympho- and plasmocytosis are retarded on the background of an increased eosinophilic and mast cell reaction.     

Toxicity of tobramycin in single and multiple administrations to laboratory animals]

The LD50 of tobramycin sulphate administered intravenously, intraperitoneally, subcutaneously and orally to albino mice was 77 (73--82), 262 (234--294), 560 (500--627) and greater than 10500 mg/kg respectively. With an increase in the rate of intravenous administration tobramycin toxicity increased. When tobramycin sulphate was administered subcutaneously daily in multiple doses equivalent to the daily therapeutic doses from humans (calculated for the body surface) and in the doses 2--3 times higher than the above therapeutic ones, the function of the kidneys, liver and the Preier's reflex did not significantly change. When the doses were 8--10 times higher than the therapeutic ones, an increase in the urea level in the blood serum, disappearance and a decrease in the Preier's reflex were observed. The impairment of the kidney function was accompanied by degenerative changes in the convoluted tubules of the kidneys, ischemia of the renal glomeruli and appearance of protein secretion in their capsule cavities. The picture of the peripheral blood did not suffer significant changes. The studies on the acute and chronic toxicity of tobramycin sulphate prepared at the Institute of New Antibiotics showed that the drug did not differ from the import tobramycin samples.     

Effect of mexidol on hemopoietic system in conditions of an emotional stress after exposure to ionizing radiation

The emotional stress after an irradiation can complicate the current of radiative defeats. At an emotional stress developing in early terms after an irradiation in low doses, are reduced adaptive and compensator capabilities of hemopoietic system. The emotional stress after a lethal dose irradiation inhibits the post-radiation recovery of haemopoiesis, aggravates the course of acute radiation disease and decreases the efficiency of the radioprotector--indralin. These disorders are especially pronounced under a prolonged and intensive stress. The use of the mexidol, having anxiolytic and antistress by activity, made it possible to arrest completely disturbances in the development of adaptive reactions to stress in the blood system and to normalize its compensatory potentialities in animals under conditions of combined influence of intensive long-term emotional stress and of low-dose irradiation. In the case of lethally irraiated animals, the treatment of stressed animals with mexidol favorably influenced the course of acute radiation disease, enhanced recovery processes in the blood system. Under these conditions, the use of mexidol completely removes the negative effect of emotional stress in indralin-protected animals. The pharmacological correction by mexidol from displays of an intensive emotional stress, developing after an irradiation in various doses, can be a part in system of medical measures.     

Results of an experimental study of the pharmacokinetics of polymyxin B sulfate]

Pharmacokinetics of polymyxin B sulfate of Soviet production was studied in various species of animals with the use of different administration routes and dosage. After a single intramuscular administration of the drug to dogs in doses of 1.1 and 2.2 mg/kg the antibiotic was detected within 5 hours at the maximum level during the 1st hour. A two-fold increase of the dose was accompanied by 1.5 times increase in the antibiotic level. Repeated administrations of polymyxin B sulfate in a dose of 4.5 mg/kg did not result in an increase in the blood level as compared to a single use of the drug. When polymyxin B sulfate was administered intravenously, the concentration peak was observed in 15 minutes independent of the dosage. Later the antibiotic level decreased. The maximum level of the drug in the mice was observed 1 hour after its intramuscular administration in a dose of 8 mg/kg, the highest levels being registered in the kidney tissues and urine.     

Measurement of urinary clusterin as an index of nephrotoxicity.

Measurements of tissue immunoassayable clusterin, a protein associated with programmed cell death and tissue reorganization, were performed in rats treated with nephrotoxic doses of gentamicin sulfate. Adult Lewis rats were treated with 100 mg/kg/day of gentamicin sulfate for 12 days. Urine, serum, and tissue levels of clusterin protein were measured, as were urinary N-acetyl beta-glucosaminidase (NAG) and serum creatinine levels. Induction of renal injury by gentamicin was detectable within 4 days by increased levels of urinary N-acetyl beta-glucosaminidase (from 280 +/- 66 (mean +/- SD) to 910 +/- 210 nmol/mg creatinine), and within 9 days of initiating gentamicin treatment by increased serum creatinine (from 0.5 +/- 0.1 to 1.2 +/- 0.4 mg/dl). Paralleling these changes, renal, urinary, and serum levels of clusterin increased 10-, 116-, and 3-fold (P less than 0.05). Treatment with gentamicin sulfate did not increase clusterin levels in the seminal vesicle, ventral prostate, testis, or epididymis. The measurement of urinary or serum clusterin may play a role in the early detection of renal injury.     

Methylmalonic acid administration induces DNA damage in rat brain and kidney

Accumulation of methylmalonic acid (MMA) in tissues and biological fluids is the biochemical hallmark of methylmalonic aciduria. Affected patients present renal failure and severe neurological findings. Considering that the underlying pathomechanisms of tissue damage are not yet understood, in the present work we assessed the in vivo e in vitro effects of MMA on DNA damage in brain and kidney, as well as on p53 and caspase 3 levels, in the presence or absence of gentamicin (acute renal failure model). For in vitro studies, tissue prisms were incubated in the presence of different concentrations of MMA and/or gentamicin for one hour. For in vivo studies, animals received a single injection of gentamicin (70 mg/kg) and/or three injections of MMA (1.67 μmol/g; 11 h interval between injections). The animals were killed 1 h after the last MMA injection. Controls received saline in the same volumes. DNA damage was analyzed by the comet assay. We found that MMA and gentamicin alone or combined in vitro increased DNA damage in cerebral cortex and kidney of rats. Furthermore, MMA administration increased DNA damage in both brain and kidney. Gentamicin per se induced DNA damage only in kidney, and the association of MMA plus gentamicin also caused DNA damage in cerebral cortex and kidney. On the other hand, p53 and caspase 3 levels were not altered by the administration of MMA and/or gentamicin. Our findings provide evidence that DNA damage may contribute to the neurological and renal damage found in patients affected by methylmalonic aciduria.     

Effects of vanadyl sulfate on kidney in experimental diabetes

The aim of this work was to investigate the biochemical and histological effects of vanadyl sulfate on blood glucose, urea, and creatinine in serum and nonenzymatic glycosylation and glutathione levels in kidney tissue of normal and streptozotocin (65 mg/kg) diabetic rats. Vanadyl sulfate was administered by gavage at a dose of 100 mg/kg. After 60 d of treatment, serum urea, creatinine, and blood glucose levels significantly increased in the diabetic group but not so in the vanadyl sulfate, which showed significantly reduced serum urea and blood glucose levels and a nonsignificant reduction of serum creatinine levels. Nonenzymatic glycosylation was increased and the glutathione level was decreased in the kidney tissue of diabetic rats. Treatment with vanadyl sulfate reversed these effects. Degenerative changes were detected in diabetic animals by electron and light microscopy. Although there are individual differences in diabetic animals given vanadium, some reduction of degenerative changes were observed.     

Study of general toxic and organotropic properties of clindamycin in long-term experiments]

The action of clindamycin monohydrate on the general state and weight rise, liver and kidney functions, peripheral blood count and pathomorphological state of the viscera was studied on rats in chronic experiments. Clindamycin was administered to laboratory animals orally in doses of 50, 100, 150 and 300 mg/kg. It was shown that some adverse reactions to the drug and in particular disorders in blood coagulation and morphological changes in the intestine did not depend on its dose and were due to duration of the drug use and probable development of dysbacteriosis. At the same time the disorders in the liver and kidney functions though transitory did depend, to a greater extent, on the dose and were evident after the antibiotic overdosage.     

Accumulation of sulfate labelled with S35 by rat tissue in vitro

Rat kidney slices incubated in vitro may show, in parallel with other shifts in electrolyte content, a striking capacity for accumulating sulfate ion (sulfate labelled with S(35)). The uptake is reversed or reduced by CN(-), cooling to room temperature, and by interference with adequate oxygenation. Under the conditions of the experiment, the presence in the medium of sodium acetate and glucose as substrates was found to be without measurable effect on the accumulation. The extent of sulfate uptake is related to the ionic composition of the medium in which the tissue is incubated, for the uptake occurs optimally only in the presence of a K(+) level of about 0.04 M, and is decreased as the concentration of Na(+) rises. Likewise, when Ca(++), Mg(++), or choline is present in the medium, sulfate accumulation may be depressed. In addition to renal cortex, kidney medulla and liver showed capacity for sulfate accumulation, whereas no convincing evidence for significant uptake was obtained with strips of aorta, colon, or diaphragm.     

DNA damage in the kidney tissue cells of the fish Rhamdia quelen after trophic contamination with aluminum sulfate

Even though aluminum is the third most common element present in the earth''s crust, information regarding its toxicity remains scarce. It is known that in certain cases, aluminum is neurotoxic, but its effect in other tissues is unknown. The aim of this work was to analyze the genotoxic potential of aluminum sulfate in kidney tissue of the fish Rhamdia quelen after trophic contamination for 60 days. Sixty four fish were subdivided into the following groups: negative control, 5 mg, 50 mg and 500 mg of aluminum sulfate per kg of fish. Samples of the posterior kidney were taken and prepared to obtain mitotic metaphase, as well as the comet assay. The three types of chromosomal abnormalities (CA) found were categorized as chromatid breaks, decondensation of telomeric region, and early separation of sister chromatids. The tests for CA showed that the 5 mg/kg and 50 mg/kg doses of aluminum sulfate had genotoxic potential. Under these treatments, early separation of the sister chromatids was observed more frequently and decondensation of the telomeric region tended to increase in frequency. We suggest that structural changes in the proteins involved in DNA compaction may have led to the decondensation of the telomeric region, making the DNA susceptible to breaks. Moreover, early separation of the sister chromatids may have occurred due to changes in the mobility of chromosomes or proteins that keep the sister chromatids together. The comet assay confirmed the genotoxicity of aluminum sulfate in the kidney tissue of Rhamdia quelen at the three doses of exposure.