Acute and subacute toxicity study of the ethanol extract from Lonicera japonica Thunb.

The ethanol extract from the leaves of Lonicera japonica Thunb. was evaluated for acute and subacute toxicity. The single oral dose of the ethanol extract at 5,000 mg/kg did not produce mortality or significant changes in the general behaviour and gross appearance of the internal organs of rats. In subacute toxicity study, the ethanol extract was administered orally at a dose of 1,000 mg/kg/day for a period of 14 days. The satellite group was treated with the ethanol extract at the same dose and the same period and kept for another 14 days after treatment. There were no significant differences in the body and organ weights between the control and the treated group of both sexes. Hematological analysis and clinical blood chemistry revealed no toxicity effects of the extract. Pathologically, neither gross abnormalities nor histopathological changes were observed.

Effects of Russell's viper venom on mediator production in cultured human umbilical vein endothelial cells.

Hemodynamic alterations in Russell's viper envenomation are the result of interactions of various vasoactive mediators and perhaps proinflammatory cytokines. Since vascular endothelium is likely to be exposed to high concentrations of the venom and the endothelial cell itself not only plays an important role in the physiologic control of the circulation, but also play a role in inflammation with the synthesis and secretion of proinflammatory cytokines. It was therefore, the objective of this study to determine the effects of Russell's viper venom (RVV) on proinflammatory cytokine production by cultured human umbilical vein endothelial cells (HUVEC) and the release of endothelium-derived substances. Endothelial cells were isolated from freshly obtained human umbilical cord vein and grown in tissue culture to confluence as a homogeneous population. Cells were then incubated at 37 degrees C under 5 per cent CO2 with RVV (0.2, 1.0, 5.0, and 25.0 microg/ml) or lipopolysaccharide (LPS, 10 microg/ml) for 3, 6, 12 and 24 hours. After an indicated time, the levels of endothelin-1 (ET-1); 6-keto-PGF1alpha (a stable metabolite of PGI2) tumor necrosis factor-alpha (TNF-alpha); interleukin-1beta (IL-1beta); and interleukin-6 (IL-6) in supernatants were measured by using ELISA or EIA. The effect of RVV or LPS on cell viability was also measured using MIT assay. The results showed copious amounts of ET-1 production irrespectively with the presence of RVV or LPS. Whereas, production of PGI2 (measured as 6-keto-PGF1alpha, a stable metabolite) was increased significantly higher in the RVV- and LPS-treated EC than in the control EC. However, TNF-alpha and IL-6 productions were not different among these groups. The levels of IL-1beta were very low, although IL-1beta was detectable in the group treated with RVV at a concentration of 25.0 microg/ml. In conclusion, RVV upto 25 microg/ml stimulated PGI2 production by cultured HUVEC. This effect was unlikely related to production of proinflammatory cytokines since LPS or RVV is not sufficient per se to elevate a substantial amount of EC-derived cytokines. The higher amount of IL-6 compared to TNF-alpha and IL-1beta may be produced through other pathways apart from production via a cascade of cytokines. This is the first report showing that RVV up to 25 microg/ml has no effect on prominent proinflammatory cytokine production by HUVEC. However, in blood circulation, the major source of cytokines production is monocyte-macrophage lineage cell. Thus, RVV in blood circulation may activate the production of proinflammatory cytokines mainly from those cells and subsequently induce toxicity.

Mediators and renal hemodynamics in Russell's viper envenomation.

The effects of Russell's viper venom on vasoactive mediators and renal hemodynamics were studied in five mongrel dogs. Intravenous administration of Russell's viper venom to the dogs caused a reduction of mean arterial pressure, renal blood flow, and glomerular filtration rate. The filtration fraction was decreased. This was accompanied by a rise in plasma norepinephrine, endothelin, 6-keto-PGF1 alpha, a stable metabolite of PGI2, and TXB2, a metabolite of TXA2. Plasma levels of epinephrine and dopamine showed no significant changes. The increase of plasma levels of both vasodilatator and vasoconstrictor were critical to systemic and renal hemodynamics. While vasodilatation predominated in the systemic circulation and resulted in hypotension, vasoconstriction played a major role in decreasing renal hemodynamics. Decreased renal blood flow and decreased glomerular filtration rate were the result of renal vasoconstriction and hypotension.

Caffeine clearance by two point analysis: a measure of liver function in chronic liver disease.

This study attempted to compare the pharmacokinetic parameters of caffeine in patients with chronic liver disease and in normal subjects and to define the two sampling times which are suitable for determining caffeine clearance in these patients. Ten decompensated and eight compensated cirrhotic patients, and nine patients with chronic hepatitis were given a 3.5 mg/kg single oral dose of caffeine, followed by measurement of serum caffeine concentrations at 0, 30, 60, 90 minutes and 3, 5, 10, 24 and 36 hours using the HPLC technique. Caffeine clearance and its elimination rate constant in the decompensated cirrhotic patients were significantly lower than those in the compensated cirrhotic patients and much lower than in normal subjects (p > 0.01). Caffeine clearance in chronic hepatitis patients was also significantly lower than in normal subjects. The volumes of distribution of caffeine in compensated and decompensated cirrhotic patients and normal subjects were significantly different. There was also a significant difference between normal subjects and the chronic hepatitis group. Serum caffeine clearance showed a good correlation with Child Pugh's score at r = -0.788. Two sampling times within 10 to 24 hours after oral dose of caffeine served as the best sampling points for determination of caffeine clearance by the simple equation; Cl = kel approximately Vd (Vd is a fixed value in each group). It was clearly shown that caffeine clearance, calculated by two point analysis, would be a simple and useful method for measuring liver function in chronic liver disease.

Renal and systemic hemodynamics, in falciparum malaria.

Renal and systemic hemodynamics, plasma arginine vasopressin, plasma renin activity, plasma norepinephrine, blood volume and water loading test were studied in 10 patients with falciparum malaria without renal failure. Six patients responded to water load normally, while 4 patients had a decreased response to water load. The patients with a normal water load response had normal renal and systemic hemodynamics and a normal hormonal profile. The patients with a decreased response to water load had hyponatremia, hypervolemia, high cardiac index, low systemic vascular resistance, high plasma arginine vasopressin, high plasma renin activity, high plasma norepinephrine, low creatinine and p-aminohippurate clearances, low urine sodium and high urine osmolality. They had a lower mean arterial pressure during the acute phase of the disease than during the recovery phase. The findings suggest that a decreased response to water load is due to peripheral vasodilatation which results in a decreased effective blood volume leading to the release of vasopressin and norepinephrine, increased renin activity and decreased renal hemodynamics.

In vitro nephrotoxicity of Russell's viper venom.

To assess direct nephrotoxicity of Russell's viper venom (RVV; Daboia russelii siamensis), isolated rat kidneys were perfused in single pass for 120 min. Ten micrograms/ml and 100 micrograms/ml RVV were administered 60 minutes and 80 minutes, respectively, after starting the perfusion. Furthermore, cultured mesangial cells and renal epithelial LLC-PK1 and MDCK cells were exposed to RVV (100 to 1000 micrograms/ml) for 5 minutes up to 48 hours. The IPRK dose-dependently exhibited reductions of renal perfusate flow (RPF, 7.7 +/- 2.4 vs. 16.5 +/- 0.7 ml/min g kidney wt in controls, experimental values given are those determined 10 minutes after termination of 100 micrograms/ml RVV admixture), glomerular filtration rate (GFR 141 +/- 23 vs. 626 +/- 72 microliters/min g kidney wt) and absolute reabsorption of sodium (TNa 8 +/- 1.7 vs. 79 +/- 9 mumol/min g kidney wt), and an increased fractional excretion of sodium (FENa 60 +/- 7 vs. 8 +/- 0.8%) and water (FEH2O 68 +/- 3.2 vs. 13 +/- 1.2%). Urinary flow rate (UFR) showed both oliguric and polyuric phases. Functional alterations of this type are consistent with ARF. Light and electron microscopy of perfusion fixed IPRK revealed an extensive destruction of the glomerular filter and lysis of vascular walls. Various degrees of epithelial injury occurred in all tubular segments. In cell culture studies RVV induced a complete disintegration of confluent mesangial cell layers, beginning at concentrations of 200 micrograms/ml. In epithelial LLC-PK1 and MDCK cell cultures only extremely high doses of RVV (> 600 and 800 micrograms/ml, respectively) led to microscopically discernible damage. These results clearly demonstrate a direct dose dependent toxic effect of RVV on the IPRK, directed primarily against glomerular and vascular structures, and on cultured mesangial cells.

Changes in renal hemodynamics induced by Russell's viper venom: effects of indomethacin.

The effects of Russell's viper venom on renal hemodynamics were studied in dogs. Intravenous injection of venom resulted in systemic hypotension, decreased renal blood flow and glomerular filtration rate. Venom injection in dogs pretreated with indomethacin caused less hypotension and less decrease in renal blood flow without changes in blood pressure and glomerular filtration rate. When the venom was injected directly into the renal artery, there was systemic hypotension, but urine flow was increased and renal blood flow and glomerular filtration rate were well maintained. Urinary N-acetyl-beta-D-glucosaminidase was increased. Direct injection of the venom into the renal artery in indomethacin-pretreated dogs decreased renal blood flow and glomerular filtration rate without change in systemic blood pressure. The findings indicate that the venom has a renal vasodilating effect which is prostaglandin mediated and also causes direct tubular injury. Renal blood flow is the net result of renal perfusion pressure, renal vasoconstriction and renal vasodilatation effects.

Intrarenal hemodynamic abnormality in severe form of glomerulonephritis: therapeutic benefit with vasodilators.

Intrarenal hemodynamic and tubular function has been assessed in 16 patients who presented clinically with hypertension, hematuria and severe renal functional impairment. Twelve of these 16 patients had histopathologic classification as DPGN (3 cases), MPGN (3 cases) and FSGS (6 cases). The initial assessment of intrarenal hemodynamics in 11 patients revealed strikingly increased afferent (RA) and efferent arterioles (RE), filtration fraction (FF), intraglomerular capillary hydrostatic pressure (PG), whereas, there was marked reduction in renal plasma flow (RPF), in ultrafiltration coefficient (KFG) and in glomerular filtration rate (GFR). Tubular transporting defect as being reflected by enhanced fractional excretions of solutes was also observed. Both enhanced TXB2 production and diminished PGI2 may be in part responsible for the marked reduction of RPF and elevated intrarenal resistance. In light of the preceding intrarenal hemodynamics alteration, therapeutic intervention with vasodilators consisting of dipyridamole, calcium channel blocker and angiotensin convertase inhibitor has been accomplished with clinical improvement in glomerular and tubular functions following the improvement in intrarenal hemodynamics. Thus, this abnormal intrarenal hemodynamics renders a supportive view of the hemodynamically mediated glomerulo-tubulo-interstitial injury to be central to the pathogenetic mechanism.