Morphofunctional aspects of liver regeneration in experimental correction of toxic hepatitis

It is demonstrated that cytoplasmic extract of rat pup liver stimulates cellular and intracellular regeneration of hepatocytes exposed to the toxic agent CCl₄. Injection of liver cytosol stabilizes lysosomal membranes, increases the coefficient of energy efficiency of mitochondria, and activates proliferation of polyploid hepatocytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 656–659, June, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Evaluation of microsomal and mitochondrial oxidation in rat liver in tetracycline-induced hepatosis

A satistically significant decrease in the content of cytochromes P-450 and b₅ and in the activity of aniline hydroxylase and p-nitroanisole demethylase occurs in rat liver microsomes during the development of experimental acute fatty hepatosis develoing within a 24-h period after intraperitoneal administration of 125 mg/kg tetracycline hydrochloride. Under these experimental conditions tetracycline hydrochloride elicits only an insignificant disintegrating effect on oxidative phosphorylation in liver mitochondria. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 612–615, December, 1994     

Effect of adaptation to moderate physical loads on the increased resistance of the isolated heart to ischemia and reperfusion

Adaptation to physical loads elicits pronounced anti-ischemic and antireperfusion effects on the isolated heart. By the 20th min of total ischemia contracture in the hearts of adapted animals is much less than that in the control group. During reperfusion of hearts from adapted animals the degree of restoration of the contractile force was 6-fold higher, contracture was lesser, and the total period of tachycardia and fibrillation were 3-fold shorter than in the control. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 25–27, January, 1995 Presented by S. S. Debov, Member of the Russian Academy of Medical Sciences     

The content of tocopherol and lipid peroxidation products in the tissues of rats with genetically determined hyperproduction of free oxygen radicals

It is shown that at the age of 2–3 months S rats with genetically determined hyperproduction of free radicals have the same content of tocopherol in the heart, epididymal fat, adrenals, liver, and liver mitochondria as Wistar rats but a lower content of plasma tocopherol. At 10–12 months, the tocopherol content in all studied tissues and organs, except the liver, is higher than in young S rats and age-matched Wistar rats. This is regarded as a compensatory response facilitating the stabilization of LPO under conditions of increased free radical formation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 282–284, March, 1996     

Accumulation of ATP by plasma membranes of human and rat hepatocytes induced by some growth factors and phosphatidylcholine

Using the method of ATP luminometry it is shown that crude membrane preparations from human and rat hepatocytes accumulate ATP 20–100 nmol/mg protein during a 1-min incubation under conditions of oxidative phosphorylation. Application of appropriate inhibitors shows that a possible contamination of the membrane preparations with mitochondria does not contribute to this ATP accumulation. Phosphatidylcholine, tumor necrosis factor, and cell proliferation factor markedly stimulate the accumulation of ATP by plasma membraneenriched particles isolated from rat and human liver. The hepatocyte plasma membrane is shown to be able to synthesize ATP from inorganic phosphate and ADP using the aerobic mechanism. ATP in the plasma membrane is assumed to participate in the transmembrane signal transduction from growth factors to the cell effector systems. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 271–274, March, 1996 Presented by V. D. Fedorov, Member of the Russian Academy of Medical Sciences     

Histochemical study of myocardial metabolism in experimental massive pulmonary embolism

The period immediately following massive pulmonary embolism largely determines its further course, that is, whether compensation will occur or whether heart failure will ensue. Prognostically favorable or unfavorable histochemical characteristics of myocardial metabolism during this period are revealed in this study. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 647–650, December, 1995 Presented by V. S. Savel'ev, Member of the Russian Academy of Medical Sciences     

Effect of purine antagonists on the cAMP level in lymphocytes and bone marrow lymphoblasts

The effect of the purine receptor ligands N-ethylcarboxamide adenine and adenosine and of the purine antagonists mercaptopurine and azathioprine on the intracellular cAMP content in human peripheral blood lymphocytes and bone marrow lymphoblasts was studied. All preparations tested induced an increase in the cAMP level in peripheral blood lymphocytes. The selective immunosuppressive effect of adenosine antagonists may be due to their ability to modulate the activity of adenylate cyclase in lymphoid cells. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o . 3, pp. 294–296, March, 1995     

Effect of cortisol and pertussis toxin on the cAMP concentration in human lymphocytes

It is demonstrated that pertussis toxin and hydrocortisone potentiate the adenosine-induced rise of the cAMP concentration in lymphocytes. Hydrocortisone elicits an immediate (for the simultaneous addition of adenosine and cortisol) and reversible effect. The effect of pertussis toxin has a latency and is irreversible. Added together, these agents exert no cumulative effect. It is assumed that hydrocortisone and pertussis toxin have the same target — The inhibiting regulatory protein G_i. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 2, pp. 171–173, February, 1995 Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences     

Lipid peroxidation parameters in the internal organs of rats with different degrees of resistance to hypoxia

Lipid peroxidation and the antioxidant system of the heart, liver, and brain are studied in adult male Wistar rats with high and low resistance to hypoxia tested by “raising” to an altitude of 11.5 km and in intact outbred rats. These parameters are found to be the same in the brain of low- and high-resistance rats, while the brain content of lipid peroxidation products is higher in both groups of Wistar rats compared with outbred rats. The heart and liver parameters are coupled to the resistance to hypoxia. Antioxidant activity prevails over lipid peroxidation in the hearts and livers of high-resistance rats, confirming that oxidation plays a major role in the damaging and lethal effects of acute hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp 26–29, January, 1996 Presented by A. I. Archakov, Member of the Russian Academy of Medical Sciences     

Comparison of lipid peroxidation parameters in the heart,liver, and brain of rats with different degrees of resistance to hypoxia

The relationship between the intensity of lipid peroxidation and the activity of the antioxidant system in the heart, liver, and brain is studied in male Wistar rats with low and high resistance to hypoxia tested by being “raised” to an altitude of 11.5 km and in intact outbred rats. It is found that in all groups of rats the content of lipid peroxidation products is highest in the liver, lower in the heart, and lowest in the brain. In all groups, the rate of the ascorbate-induced lipid peroxidation is highest in the brain, lower in the liver, and lowest in the heart. The activity of the antioxidant system is highest in the brain, lower in the liver, and lowest in the heart of low-resistance and outbred rats, while in high-resistance rats it is the same in all the organs. Thus, the difference in the parameters of lipid peroxidation and, particularly, of the antioxidant system in the studied organs is most pronounced in rats with a low resistance to hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 138–143, February, 1996 Presented by A. I. Archakov, Member of the Russian Academy of Medical Sciences     

Antenatal effects of ethanol and limontar on lipid peroxidation and the antioxidant defense system in the brain and liver of rat progeny

In contrast to short-term exposure, prolonged exposure to ethanol in the anternatal period is found to inhibit lipid peroxidation in the brain and liver of rats. Activation of the system of antioxidant defense in the brain and liver is observed after both short-and long-term exposure to ethanol. After short-term ethanol exposure, limontar normalizes lipid peroxidation. Translated fromByulleten' Eksperimental'noii Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 41–44, January, 1994 Presented by M. Ya. Studenikin, Member of the Russian Academy of Medical Sciences     

Polyploidy in the myocardium and compensatory reserve of the heart

The mammalian heart is a polyploid organ. Cardiac myocytes undergo polyploidization in the early postnatal ontogeny, and the degree of their polyploid depends on the conditions of heart growth. The myocardium of healthy persons is characterized by considerable individual variability of polyploidy. The principal mechanism by which normal and compensatory growth of the heart occurs in adult mammals is through increases of cytoplasmic mass in postmitotic myocytes. In the normal myocardium, the protein mass of myocytes does not correspond to the gene dosage, while their protein mass in a hypertrophic myocardium becomes a multiple of their ploidy. The capacity of polyploid myocytes to grow so as to double their mass constitutes the reserve of cardiac growth. This reserve, which is laid down in the early ontogeny, materializes in response to functional overloading of the heart in adult life. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 5, pp. 454–459, May, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Regeneration of the liver after partial hepatectomy with a beam of ionized plasma

Eighty guinea pigs underwent resection of the left lateral lobe of the liver, performed with a beam of ionized plasma. Morphological analysis 32 and 45 hours after partial hepatectomy revealed minor damage to the parenchyma to a depth of 300–400 μ. Autoradiography showed proliferative activity in the organ to occur in the early post-operative period. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 431–432, April, 1995 Presented by B. T. Velichkovskii, Member of the Russian Academy of Medical Sciences     

Role of cholinergic regulation of the heart in the protective antiarrhythmic effect of adaptation to continuous moderate stress

Rats were adapted to the continuous action of moderate immobilization stress for 1, 5, and 15 days. Thereafter the threshold of ventricular fibrillation and the heart rate were compared with biochemical indexes of adrenergic and cholinergic regulation of the heart, namely, catecholamine, cAMP, and cGMP content, acetylcholinesterase and choline acetyltransferase activity, the number and affinity of cardiac muscarinic receptors, and the catecholamine content in the adrenals. The threshold of ventricular fibrillation fell on the 1st day due to a predominance of the adrenergic regulatory effect over the cholinergic. Adaptation for 5 days is attended by a rise of the threshold of ventricular fibrillation to the norm and by marked bradycardia, both these shifts being abolished by atropine. Elevation of the heart's resistance to arrhythmias stems from the prevalence of cholinergic regulation. Equilibrium between the cholinergic and adrenergic effects on the heart was found as a results of 15-day adaptation. The normal threshold of ventricular fibrillation and the increased cardiac resistance to arrhythmia were preserved and dictated largely by adaptive changes at the cardiomycyte level. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120. N ^o 7, pp. 36–39, July, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

A method for monitoring toxic damage to the liver,based on measurement of total water and its magnetic relaxation characteristics

Acute poisoning of rats with the hepatotropic poison tetrachloromethane was accompanied by increases in the liver content of total water and its spin-lattice (T ₁) and spin-spin (T ₂) relaxation times and by a decrease in theT ₁/T ₂ ratio, with reversal of the correlation betweenT ₁ andT ₂. The antihypoxic agent sodium γ-oxybutyrate normalized water metabolism in the liver almost completely. It is concluded that total water content andT ₁ are the more informative parameters for monitoring both toxic liver damage and the efficacy of its pharmacological correction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 584–586, December, 1995 Presented by Yu. A. Vladimirov, Member of the Russian Academy of Medical Sciences     

Physicochemical properties of membranes and functional status of liver mitochondria in rats with an inherited capacity for increased radical formation

Liver mitochondria of inbred W/SSM rats with inherited increased radical formation reveal the following anomalies: inhibition of oxidative phosphorylation, a lowered transmembrane potential, and alterations in protein-lipid interaction. The membrane viscosity and osmotic stability of mitochondria are unaffected. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 628–631, June, 1995     

Rat model of acute tetracycline hepatosis and its dynamic predictors

It is demonstrated that intraperitoneal administration of tetracycline hydrochloride in a dose of 125 mg/kg leads to the development of acute fatty hepatosis in rats within a 24-h period, by which time the maximum accumulation of lipids and triacylglycerides is observed in the liver. In addition, a direct dependence is established between the severity of fatty hepatosis and a decrease in the cytochrome P-450 content. The cytochrome P-450 content is a dynamic predictor of tetracycline fatty hepatosis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 603–605, December, 1994     

Changes of the total water content and magnetic relaxation characteristics of the liver and small intestine in vagotomy

Bilateral subdiaphragmatic truncal vagotomy in rats results in a disturbance of water metabolism in the liver and small intestine which manifests itself in an increase of the total water content, prolongation of the spin-lattice and spin-spin relaxation, and in a distortion of the correlation between them. The dynamics of water metabolism is of a onepeak nature in the liver with a maximum after 7 days, whereas in the small intestine it is of a dual-peak type with peaks at 7 and 30 days. Near-normalization of the water balance in the digestive organs occurs 220 days later. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 442–444, October, 1995 Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences     

Second messengers contribute to cholinoceptor modulation by amiridine inHelix lucorum neurons

The effect of amiridine on the local inward acetylcholine current and its volt-ampere characteristic are studied by the two-electrode method of membrane voltage clamp in identified RPa3 and LPa3helix lucorum neurons pretreated with forskolin, sodium nitroprusside, A23187, and EGTA. The results suggest that second messengers (Ca²⁺, NO, cGMP, and cAMP) are implicated in the amiridine-mediated regulation of cholinoceptors inHelix lucorum neurons. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 470–473, November, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effects of some steroid hormones on Ca2+ transport and oxidative metabolism of isolated mitochondria

Effects of prednisolone, estradiol, and testosterone on the transport of Ca²⁺ and the respiration induced by it in the heart and liver mitochondria of rats were studied. Prednisolone and testosterone were found to reduce the Ca-accumulating capacity of the mitochondria, the rates of ion entry and exit, and the rate of Ca²⁺-induced respiration. Estradiol, while inhibiting Ca²⁺ transport across mitochondrial membrane, did not influence the respiration in the phase of Ca²⁺ absorption, but accelerated it in the phase of ion exit. These data suggest that due to their lipophilic properties, the steroids become incorporated in the mitochondrial membrane, thereby changing its viscosity and permeability and limiting the mobility of transmitter proteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 616–618, December, 1994