Action of streptokinase on the hemostatic indices of rabbits with a toxic lesion of the liver due to carbon tetrachloride

The rabbits with CCl4-induced hepatic failure have revealed changes in hemostasis responses to streptokinase administration. The main distinction of hepatic dystrophy was the depression of plasma fibrinolytic activity accompanying the decrease in fibrinogen and antiplasmin concentrations. Streptokinase administration to rabbits with productive inflammatory liver disorders produced changes in hemostasis identical to those observed in intact rabbits, fibrinogen levels, however, remained unchanged. The common feature of all the toxic liver disorders is the increase of antithrombin III levels after streptokinase administration, whereas the antithrombin levels in the control animals were decreased.     

Is ethanol a stressogenic factor for rats with a developed alcohol motivation?

The male outbred rats, placed in common cages, demonstrated dose- and time-dependent increase of blood plasma ACTH level after handling and acute ethanol administration (1 and 4 g/kg). The pituitary response of isolated rats under condition of free choice between water and 15% ethanol solution was more pronounced after handling. Ethanol (4 g/kg) did not increase plasma blood level ACTH in isolated alcohol motivated rats. It also prevented blood plasma ACTH rise under condition of handling. The dual role of acute ethanol as a stressogenic and antistressogenic factor in naive and alcoholic rats is discussed.     

Quercetin metabolites inhibit copper ion-induced lipid peroxidation in rat plasma

The oxidative susceptibility of plasma obtained from rats after intragastric administration of quercetin was studied to know whether or not quercetin acts as an in vivo antioxidant after metabolic conversion. Quercetin was raised in the rat blood plasma essentially as glucuronide and/or sulfate conjugates. The plasma obtained from rats after quercetin administration was more resistant against copper sulfate-induced lipid peroxidation than the control plasma on the basis of the accumulation of cholesteryl ester hydroperoxides and the consumption of α-tocopherol. The results strongly suggest that some conjugated metabolites of quercetin act as effective antioxidants when plasma is subject to metal ion-induced lipid peroxidation.     

Effect of purified recombinant human erythropoietin on anemia in rats with experimental renal failure induced by five-sixth nephrectomy

Recombinant human erythropoietin (rHuEPO) was purified from the conditioned media of Chinese hamster ovary cells with a transfected human erythropoietin gene. We investigated the effects of the rHuEPO in rats with renal anemia induced by partial nephrectomy. Five-sixth nephrectomy resulted in renal failure with anemia. Twenty-five days after the operation plasma urea nitrogen was increased about 2.5 times, and the red blood cell count, hematocrit, and hemoglobin concentration fell to 85% of normal. The reticulocyte count and plasma erythropoietin level did not change such as they do in patients with anemia due to chronic renal failure. Both total red blood cell volume and the plasma iron turnover rate were depressed in five-sixth nephrectomized rats compared with normal rats.The five-sixth nephrectomized rats were injected with rHuEPO (60 IU/kg) intravenously every second day for a total of six injections. After three injections of rHuEPO, circulation volume of total red blood cells was increased from 9.9 ml to 14.6 ml, and the plasma iron turnover rate was increased from 1.03 mg/kg/day to 2.12 mg/kg/day, and the reticulocyte count was also increased. After six injections, a marked increase of the red blood cell count, hematocrit, and hemoglobin concentration were observed. Plasma urea nitrogen and the creatinine levels as indications for renal function did not change after rHuEPO administration in both normal and five-sixth nephrectomized rats.In conclusion rHuEPO has a potent erythropoietic action and it is possible to cure the anemia caused by renal failure.     

Acute hyperhomocysteinemia alters the coagulation system and oxidative status in the blood of rats

In the present study, we investigated the effect of the acute administration of homocysteine (Hcy) on parameters of the coagulation system, as well as fibrinogen and nitrite levels in the blood of rats. In addition, we evaluated the effect of acute hyperhomocysteinemia on thiobarbituric acid-reactive substances in plasma and on antioxidant enzymes activities (superoxide dismutase, catalase, and gluthatione peroxidase) in the erythrocytes of rats. Wistar rats, aged 29 days, received a single subcutaneous dorsal injection of saline (control) or Hcy (0.6 μmol/g body weight). Fifteen minutes, 1 h, 6 h or 12 h after the injection, the rats were euthanized and the blood, plasma, and erythrocytes were collected. Results showed that Hcy significantly increased platelet count in the blood and plasma fibrinogen levels of rats at 15 min and 1 h, but not at 6 h and 12 h, when compared with the control group. Prothrombin time, activated partial thromboplastin time, and nitrite levels significantly decreased in plasma at 15 min and 1 h, but not at 6 h and 12 h after Hcy administration. In addition, hyperhomocysteinemia increased thiobarbituric acid-reactive, an index of lipid peroxidation, in plasma at 15 min and 1 h; decreased the superoxide dismutase and gluthatione peroxidase activity, and increased the catalase activity at 15 min in erythrocytes of rats, suggesting that acute Hcy administration may alter the oxidative status in the blood of rats. Our findings suggest that hypercoagulability and oxidative stress can occur after acute hyperhomocysteinemia, possibly in association, at least in part, with the vascular dysfunction and thromboembolic complications observed in homocystinuric patients.     

Lung-specific delivery of cytokines induces sustained pulmonary and systemic immunomodulation in rats

The recombinant cytokines IFN-gamma and TNF-alpha stimulate several macrophage-mediated functions important in host defense. However, systemic administration of cytokines may be limited by significant host toxicity. We investigated whether aerosolized cytokines can stimulate alveolar macrophage and blood monocyte function, and whether they induce an inflammatory response in the lungs of normal rats. We found that aerosolized murine rIFN-gamma or recombinant human TNF-alpha increased IL-1 production by both alveolar macrophages and blood monocytes for at least 5 days after administration. Furthermore, murine rIFN-gamma increased the expression of Ia Ag on alveolar macrophages and human rTNF-alpha increased alveolar macrophage- and blood monocyte-mediated tumor lysis. Sequential aerosolization of IFN-gamma and TNF-alpha significantly increased both IL-1 release and Ia expression compared to either cytokine administered alone. Aerosolized human rTNF-alpha achieved lung levels comparable to those produced by an i.v. TNF-alpha dose reported to cause diffuse organ injury and death in rats. However, plasma TNF-alpha levels were several thousand-fold lower after aerosol administration. Aerosolized cytokines did not induce lung edema or an inflammatory cell infiltrate within the airways or alveoli. Aerosolized human rTNF-alpha alone, or murine rIFN-gamma and human rTNF-alpha, induced margination of leukocytes in pulmonary blood vessels 1 day after aerosolization, and a few small foci of pulmonary hemorrhage 5 days later. We conclude that aerosol administration of IFN-gamma or TNF-alpha enhances both pulmonary and systemic monocyte function, and that the combination of IFN-gamma and TNF-alpha produce additive or synergistic effects. Aerosolized cytokines induce only a minimal pulmonary inflammatory response. Aerosolized TNF-alpha produces high cytokine levels in the lung but very low uptake into the circulation.     

Kinetics of in vitro fibrinolysis by plasmin and a plasmin-streptokinase equimolar complex]

Kinetics of fibrinolysis by plasmin and plasmin streptokinase complex have been studied using fibrin gels formed from purified fibrin and human blood plasma. The gels were placed into buffer or blood plasma. The contributions of plasminogen and alpha 2-antiplasmin present or absent in both phases to the kinetics of fibrinolysis were quantitatively estimated. In the complex catalyzed fibrinolysis, plasminogen activation reaction dominated whereas in plasmin-catalyzed fibrinolysis, the inhibitor involved reaction, suppressing the process, prevailed.     

Method of simultaneous determination of kallikrein, plasmin and thrombin precursors and inhibitors in human blood plasma]

Prekallikrein, plasminogen and prothrombin of human blood plasma have been separately activated by caolin streptokinase and thromboplastin. By measuring the TAME-esterase (N-d Tozy-L-arginine methyl ester) activity of each enzyme and its changes in the course of plasma incubation with the activator, it was possible to estimate the values of precursors of kallikrein, plasmin, thrombin and their inhibitors. Evidence is given that under conditions described the activation is specific of each enzyme and does not affect the level of the two other percursors. The method has been developed in two modifications, permitting to obtain the value of seven parameters in 0.4--0.7 ml of blood plasma.     

Circulating endothelial cells as a sign of vessel wall lesions.

A new method of endothelaemia estimation was used to investigate the production of vessel wall lesions by various drugs in rats. Increased endothelaemia was observed after endotoxin, activation of the blood contract system, hyaluronidase, streptokinase, anoxia and vasoactive drugs.     

内毒素在大剂量顺铂所致大鼠急性肾损伤过程中的变化及意义

目的利用大剂量顺铂（cisplatin,DDP）所致大鼠急性肾功能衰竭的动物模型,观察外周血内毒素（endotoxin）在大鼠急性肾损伤中的变化及其意义。方法SD大鼠36只,雌雄各半,依体重随机分为DDP用药6h、48h、对照组和生理盐水（NS）用药6h、48h、对照组,每组6只。10mg／kgDDP单次腹腔内注射,等量Ns对照。观察并记录用药后对照组大鼠的毒副反应;用药6、48h各组大鼠无菌条件下心脏穿刺取血、肝素抗凝,检测外周血内毒素含量,同时内眦静脉取血,测定血清尿素氮、肌酐浓度,并进行统计学分析。结果DDP用药后6h,大鼠体重开始明显降低,用药48h后,大鼠腹泻逐渐加重,用药3d后大鼠死亡。DDP用药后6h大鼠血尿素氮、肌酐的含量与对照组比较差异无显著性（P〉0．05）;DDP用药后48h血尿素氮升至（18．71±9．9）mmol／L,明显高于对照组（7．48±0．6）mmol／L（P〈0．05）,同时血肌酐含量亦升至（49．6±14．1）μmol／L,与对照组（27．17±1．7）μmol／L比较差异具有显著性（P〈0．05）。DDP用药后6h所有大鼠外周血内毒素含量都低于0．0218Eu／rrd最低检出限,明显低于NS对照组大鼠（0．3141±0．1477）Eu／ml（P〈0．01）;DDP用药后48h大鼠外周血内毒素的含量增高均超过0．70Eu／ml最高检出限,明显高于NS对照组大鼠（0．1661±0．1198）Eu／ml（P〈0．01）。结论外周血内毒素含量的变化与大剂量顺铂所致大鼠急性肾损伤早期的发病机制无关,但与大鼠肾功能衰竭有关的发生相关。     

Effect of dipeptide vilon on emotional stress resistance in rats

Effects of synthetic thymomimetic vilon on open field behaviour, immediate early gene c-Fos expression in paraventricular hypothalamus properties of organs sensitive to emotional stress, and characteristics of albumin in the blood plasma in male Wistar rats, were investigated and are discussed in the article. It is shown that intraperitoneal vilon injection rises the resistance against emotional stress according to prognostic indexes open field behaviour. Vilon administration also inhibits hypertrophy of the adrenals, involution of the thymus, and elevates concentration of albumin in the blood plasma. The number of Fos-immunoreactive neurons in the paraventricular hypothalamus was lower after vilon administration especially in rats resistant against emotional stress.     

ACE activity during the hypotension produced by standardized aqueous extract of Cecropia glaziovii Sneth: A comparative study to captopril effects in rats

To evaluate the effect of the standardized aqueous extract (AE) of Cecropia glaziovii Sneth on the plasma angiotensin I converting enzyme (ACE-EC 3.4.15.1) activity, rats were treated with a single dose of AE (1 g/kg, p.o.) or repeatedly (0.5 g/kg/bid, p.o.) for 60 days. Captopril (50 mg/kg, p.o.) was used as positive control on the same animals. The effects on the blood pressure were recorded directly from the femoral artery (single dose), or indirectly by the tail cuff method (repeated doses) in conscious rats. The plasma ACE activity was determined spectrofluorimetrically using Hypuril-Hystidine-Leucine as substrate. The arterial blood pressure, heart rate and plasma ACE activity were not significantly modified within 24 h after a single dose administration of AE. Comparatively, blood pressure in captopril treated rats was reduced by 7-16% and heart rate was increased by 10-20% from 30 min to 24 h after drug administration. ACE activity after captopril presented a dual response: an immediate inhibition peaking at 30 min and a slow reversal to 32% up-regulation after 24 h. To correlate the drug effects upon repeated administration of either compound, normotensive rats were separated in three groups: animals with high ACE (48.8+/-2.6 nmol/min/ml), intermediate ACE (39.4+/-1.4 nmol/min/ml) and low ACE (23.5+/-0.6 nmol/min/ml) activity, significantly different among them. Repeated treatment with AE reduced the mean systolic blood pressure (121.7+/-0.5 mm Hg) by 20 mm Hg after 14 days. The hypotension was reversed upon washout 60 days afterwards. Likely, repeated captopril administration decreased blood pressure by 20 mm Hg throughout treatment in all groups. After 30 days treatment with AE (0.5 g/kg/bid, p.o.) the plasma ACE activity was unchanged in any experimental group. After captopril (50 mg/kg/bid, p.o.) administration the plasma ACE activity was inhibited by 50% within 1 h treatment but it was up-regulated by 120% after 12 h in all groups. It is concluded that the hypotension produced by prolonged treatment with AE of C. glaziovii is unrelated to ACE inhibition.     

Metrifonate and dichlorvos: Effects of a single oral administration on cholinesterase activity in rat brain and blood

Cholinesterase activities in rat forebrain, erythrocytes, and plasma were assessed after a single oral administration of metrifonate or dichlorvos. In 3-month-old rats, the dichlorvos (10 mg/kg p.o.)-induced inhibition of cholinesterase reached its peak in brain after 15–45 min and after 10–30 min in erythrocytes and plasma. Cholinesterase activity recovered rapidly after the peak of inhibition, but did not reach control values in brain and erythrocytes within 24 h after drug administration. The recovery of plasma cholinesterase activity, in contrast, was already complete 12 h after dichlorvos treatment. Metrifonate (100 mg/kg p.o.) had qualitatively similar inhibition kinetics as dichlorvos, albeit with a slightly delayed onset. Peak values were attained 45–60 min (brain) and 20–45 min (blood), after drug administration. Apparently complete recovery of cholinesterase activity was noted in both tissues 24 h after treatment. The dose-dependence of drug-induced inhibition of cholinesterase in rat blood and brain was determined at the time of maximal inhibition, i.e., 30 min after dichlorvos treatment and 45 min after metrifonate treatment. The oral ED₅₀ values obtained for dichlorvos were 8 mg/kg for brain and 6 mg/kg for both erythrocyte and plasma cholinesterase. The corresponding oral ED₅₀ values for metrifonate were 10 to 15 times higher, i.e., 90 mg/kg in brain and 80 mg/kg in erythrocytes and plasma. In rats deprived of food for 18 h before drug treatment, the corresponding ED₅₀ values for metrifonate were 60 and 45 mg/kg, respectively, indicating an about two-fold higher sensitivity of fasted rats to metrifonate-induced cholinesterase inhibition compared to non-fasted rats. Compared to 3-month-old rats, 19-month-old rats showed a higher sensitivity towards metrifonate and dichlorvos. At the time of maximal inhibition, there was a strong correlation between the degree of cholinesterase inhibition in brain and blood. These results demonstrate that single oral administration of metrifonate and dichlorvos induces an inhibition of blood and brain cholinesterase in the conscious rat in a dose-dependent and apparently fully reversible manner. While the efficiency of a given dose of inhibitor may vary with the satiety status or age of the animal, the extent of brain ChE inhibition can be estimated from the level of blood ChE activity.     

Process of platelets activation by streptokinase

This study concerns the influence of streptokinase and antistreptokinase antibodies on rabbits platelets in blood plasma depleted of plasminogen. The immune complex streptokinase-antibody causes platelets activation, whereas other investigated immune complexes didnot express such activity. Platelets aggregation wasnot detected in any case. It was determined that streptokinase induces platelets activation in the rabbit plasma with high titre of antistreptokinase antibodies in absence of plasminogen.     

Pharmacokinetic and oral bioavailability of andrographolide from Andrographis paniculata fixed combination Kan Jang in rats and human.

Validated analytical methods (HPLC, CE and GC-MS) for determining the amount of andrographolide (AND) in the blood plasma of rats and human volunteers following the oral administration of Andrographis paniculata extract (APE) and Andrographis paniculata fixed combination Kan Jang tablets were developed and used for the pharmacokinetic study. Andrographolide was quickly and almost completely absorbed into the blood following the oral administration of APE at a dose of 20 mg/kg body wt. in rats. Its bio-availability, however, decreased four-fold when a 10-times-higher dose was used. Since a large part (55 %) of AND is bound to plasma proteins and only a limited amount can enter the cells, the pharmacokinetics of AND are described well by a one-compartment model. Renal excretion is not the main route for eliminating AND. It is most likely intensely and dose dependently metabolized. Following the oral administration of four Kan Jang tablets (a single therapeutic dose, equal to 20 mg of AND) to humans, maximum plasma levels of approximately 393 ng/ml (approx. 1.12 microM) were reached after 1.5-2 hours, as quantified using a UV diode-array detection method. Half-life and mean residence times were 6.6 and 10.0 hours, respectively. AND pharmacokinetics in humans are explained well by an open two-compartment model. The calculated steady state plasma concentration of AND for multiple doses of Kan Jang (after the normal therapeutic dose regimen, 3 x 4 tablets/day, about 1 mg AND/kg body wt./day) was approximately 660 ng/ml (approx. 1.9 microM), enough to reveal any anti-PAF effect, particularly after drug uptake when the concentration of AND in blood is about 1342 ng/ml (approx. 3.8 microM, while for anti-PAF effect EC50 - 5 microM).     

Modulation of A and B cell functions by tolbutamide and arginine in the pancreas of thiamine-deficient rats

The effects of administration of glucose orally and tolbutamide or arginine intravenously on insulin and glucagon secretion and blood glucose level were studied in normal and thiamine-deficient rats. In thiamine deficiency, insulin secretion and glucose tolerance were impaired during glucose ingestion. Tolbutamide decreased the blood glucose level in both control and thiamine-deficient rats but its stimulatory effect on insulin secretion was minimal in thiamine-deficient rats unlike the control animals. Arginine did not alter substantially the blood glucose or insulin in thiamine-deficient rats, whereas it increased the insulin level in control rats. The fasting plasma glucagon level was high in thiamine deficiency. Tolbutamide increased the plasma glucagon in control rats, but did so only marginally in thiamine-deficient rats. Arginine also increased the glucagon secretion throughout the period of study in control rats. In thiamine-deficient rats the glucagon secretion was pronounced only after 20 min of arginine administration. These results suggest that an unimpaired glucose metabolism is a prerequisite to induce proper insulin secretion. Only proper insulin secretion can check the glucagon secretion rather than the increased glucose level. Hypoglycemia can induce glucagon secretion independent of the insulin level.     

Hypoglycemic activity of Swertia chirayita (Roxb ex Flem) Karst

Hexane fraction of S. chirayita (250 mg/kg body wt.) induced significant fall in blood sugar and significant increase in plasma IRI simultaneously after single oral administration without influencing liver glycogen concentration in albino rats. On the other hand, daily administration for 28 days resulted in significant lowering of blood sugar and increase in plasma IRI along with a significant rise in liver glycogen. Intestinal absorption of glucose was not inhibited by hexane fraction. It is suggested that hexane fraction of S. chirayita possibly acts through its insulin releasing effect.     

Molecular processes in the streptokinase thrombolytic therapy

The aim of this research is to evaluate the current streptokinase thrombolytic treatment and to identify or improve new techniques that will base new approaches with a higher efficiency in this area of expertise. In order to be as realistic as possible a new method was set up using magnetic vectorized nanoparticles streptokinase and human blood thrombus. The experimental data confirm the maximum 83% thrombus lyses whenever increase streptokinase concentration. It is very probable to happen because of the presence of high concentration of antiplasmin in the blood that neutralizes around half of the thrombolytic potential of the sanguine plasminogen. The experiment shows also that only free serum plasminogen are available for streptokinase action in order to generate plasmin.     

The novel peptide apelin lowers blood pressure via a nitric oxide-dependent mechanism

Apelin is an endogenous ligand of the human orphan receptor APJ. We detected apelin-like immunoreactivity in the adipocytes, gastric mucosa, and Kupffer cells in the liver. We also detected apelin-like immunoreactivity localized within the endothelia of small arteries in various organs. Further, it was found that mean arterial pressure after the administration of apelin-12, apelin-13, and apelin-36 at a dose of 10 nmol/kg in anaesthetized rats was reduced by 26+/-5, 11+/-4, and 5+/-4 mm Hg, respectively. In the presence of a nitric oxide (NO) synthase inhibitor, the effect of apelin-12 on blood pressure was abolished. Furthermore, the administration of apelin-12 (10 nmol/kg) in rats produced a transitory elevation of the plasma nitrite/nitrate concentration from a basal level of 21.4+/-1.6 to 27.0+/-1.5 microM. Thus, apelin may lower blood pressure via a nitric oxide-dependent mechanism.     

Taurine attenuates hypertension and improves insulin sensitivity in the fructose-fed rat, an animal model of insulin resistance

Fructose feeding induces moderate increases in blood pressure levels in normal rats, which is associated with hyperinsulinemia, insulin resistance, and impaired glucose tolerance. Increased vascular resistance, sodium retention, and sympathetic overactivity have been proposed to contribute to the blood pressure elevation in this model. Taurine, a sulphur-containing amino acid, has been reported to have antihypertensive and sympatholytic actions. In the present study, the effects of taurine on blood pressure, plasma levels of glucose and insulin, glucose tolerance, and renal function were studied in fructose-fed rats. Fructose-fed rats had higher blood pressure and elevated plasma levels of insulin and glucose. The plasma glucose levels were higher in fructose-fed rats than in controls at 15, 30, and 60 min after the oral glucose load. Treatment with 2% taurine in drinking water prevented the blood pressure elevation and attenuated the hyperinsulinemia in fructose-fed rats. The exaggerated glucose levels in response to the oral glucose load was also prevented by taurine administration. Thus, taurine supplementation could be beneficial in circumventing metabolic alterations in insulin resistance.