[Inhibitory effect of asymmetric dimethylarginine and NG-Monomethyl-L-arginine methyl ester on nitric oxide synthase activity]

Nitric oxide synthase [NOS] paly a role in nitric oxide [NO] generation. Despite the beneficial effects of NO on different body systems its overproduction of produce reactive nitrogen species [RNS] and nitrosilation of proteins. This study was done to evaluate the effect of asymmetric dimethylarginine [ADMA] and NG-Monomethyl-L-arginine methyl ester [L-NMMA] on inhibition of nitric oxide synthase activity. In this laboratory study, Nitric oxide synthase was extracted from 500 grams of sheep kidney by homogenization, ammonium sulphate precipitation and column chromatography on DEAE-32 Cellulose and 2', 5'-ADP-agarose. During purification, protein content was measured according to the Bradford and enzyme activity was assayed using the Griess reactions the inhibitory effects of 25 micro concentrations of ADMA and L-NMMA on purified enzyme were determined. Specific activity and yield of NOS were 0.6 units/mg protein and 0.9%, respectively. Molecular weight of purified enzyme was 54 KD with SDS-PAGE. ADMA and L-NMMA in 25 micro concentrations reduced enzyme activity by 76 and 61.2%, respectively. Km values for NOS in absence and in presence of ADMA and L-NMMA were 5.32 microM, 31.25 microM [P<0.05] and 14.29 microM [P<0.05], respectively. Vmax for NOS in absence and presence of inhibitors was not changed. ADMA and L-NMMA have competitive inhibitory effect on NOS activity and ADMA have higher inhibitory effect than L-NMMA

Thyroid stimulating hormone and leptin levels and severe growth retardation among beta - thalassemic patients

It has been proposed that Thyroid Stimulating Hormone [TSH] influences leptin secretion from adipocytes. We evaluated the association between TSH and leptin levels in thalassemic patients with growth retardation. Blood samples were collected from 30 major thalassemic patients and 24 normal subjects [range: 12 - 20 y]. Both Leptin and TSH were measured by Enzyme-Linked Immunosorbent Assay [ELISA] method. The anthropometric data were collected based on standard methods. Independent sample t-test and Pearson's correlation were used to analyze data. Patients had severe growth retardation. Mean concentration of leptin in thalassemic patients was significantly lower than normal subjects [2.26 +/- 2.61 vs 13.14 +/- 15.95 ng/ml]. The mean value of serum TSH concentration in beta - thalassemic patients was higher than normal subjects. But the difference was not statistically significant [P = 0.146]. There was no marked relationships between TSH and leptin concentrations in thalassemic patients [r= -0.022, P = 0.909] and in control group [r=0.289, P=0.214]. In both beta - thalassemic patients and normal group leptin secretion is not affected by TSH concentration

[Indentification and characterization of blood coagulation factor X activator from the venom of iranian vipera lebetina]

Snake venom particulary those belonging to Crotalidae and viperidae families, are known to contain number of components affecting blood coagulation. The Aim of this paper is to describe the isolation a specific blood coagulation factor X activator from the crude venom of Iranian Vipera lebetina. Factor X activator was purified from two hundred mg of crude venom by gel filtration on sephadex G-100 and two step ion-exchange chromatography on DEAE-cellulose [DEAE-52]. It showed a single band in sodium dodecyl sulfate-polyacrylamid gel electrophoresis [SDS-PAGE] in non-reducing condition. The mol. wt was estimated to be 78000Da by SDS-PAGE the activator, activated factor X to Xa in presence of calcium ions. It could not activate prothrombin, no had effect an fibrinogen and thus appeared to act specifically on factor X. The activator no amidolytic activtiy on factor Xa substrate benzoyl-Ile-glu-Gly-Arg-p-nitracnilide [S-2222]. It had no arginine esterase activity toward substrate benzoylagrinine ethylester [BAEE] while crude venom hydrolyzes this substrate. The results of this study showed that The activator do act specifically on factor X

[Study the effect of oxamate on rat sperm motility in vivo]

LDH- C4 is an isoenzyme of lactate dehydrogenase that is found in mature testes and spermatozoa of species with internal fertilization. Its physiological function appears related to metabolic processes that provide energy for motility and survival of spermatozoa. Oxamate is a new selective competitive inhibitor of sperm LDH- C4 with pyruvate as substrate. In the present experimental study on male rat, the effectiveness of oxamate was evaluated as a novel approach to the development of a male contraceptive. In this study, 20 adult rats were divided into 4 groups, the first used as control and the remaining three used as experimental groups. Experimental groups received different concentration, of oxamate [150, 300, 600 mg/kg/,ip] for 45 days. Control animals received normal saline solution. The sperms from the cauda division of epididymidis were collected by placing minced cauda in culture medium [T6] for one hour at 37°C in a 5% CO[2] atmosphere. Sperm motility was evaluated utilizing Makler chamber and compared with the control group. Statistical analysis was performed by the student t- test and one - way ANOVA. Progressive sperm motility in control and treated their groups were%60.3 +/- 2.8],%50 +/- 2.4],%41.5 +/- 1.9],%19 +/- 2.2] respectively. We conclude that oxamate in vivo can reduce sperm motility significantly and this reduction was concentration-dependent. The results of this work show that sperm motility can be reduced by concentration- dependent effect of oxamate under in vivo conditions