Biomedical subjects

Parvin Pasalar

Publications and source records attributed to Parvin Pasalar.

5 recordsLinked to original sources

PubMed2005

Shift work as an oxidative stressor.

BACKGROUND: Some medical disorders have higher prevalence in shift workers than others. This study was designed to evaluate the effect of night-shift-working on total plasma antioxidant capacity, with respect to the causative role of oxidative stress in induction of some of these disorders. METHODS: Two blood samples were taken from 44 workers with a rotational shift schedule, one after their day shift and one after their night shift. The total plasma antioxidant capacity of each worker was measured through the FRAP method. The impacts of age and weight were also assessed. RESULTS: The total plasma antioxidant capacity was measured in 44 shift-workers with a mean age of 36.57 years (SD: 10.18) and mean BMI of 26.06 (SD: 4.37) after their day and night shifts. The mean reduction of total plasma antioxidant capacity after the night shift was 105.8 micromol/L (SD: 146.39). Also, a significant correlation was shown between age and weight and total plasma antioxidant capacity. Age and weight were found to be inversely related to total plasma antioxidant capacity; as age and weight increased, the total plasma antioxidant capacity decreased. CONCLUSION: Shift work can act as an oxidative stressor and may induce many medical disorders. Aging and obesity in shift workers makes them more sensitive to this hazardous effect.

Journal Article↗

PubMed2005

Paradoxical dose- and time-dependent regulation of superoxide dismutase and antioxidant capacity by vitamin E in rat.

BACKGROUND: Previous data about the regulation of SOD activity as the key part of the endogenous antioxidant system by vitamin E is conflicting. METHODS: We investigated the effect of different nontoxic doses of vitamin E on erythrocyte SOD activity and plasma total antioxidant capacity in rats, receiving 0 (control group), 100, 300 and 600 mg vitamin E/kilogram of body weight intramuscularly twice a week over 6-weeks. RESULTS: We observed a linear increase in SOD activity in the first dosing group, which was significant (p<0.05) after 6th week compared to the control level. There was an increase in SOD activity at the end of 2nd and significant increase after 4th weeks, which was followed by a significant decrease at the end of 6th week in the second dosing group. In the third dosing group, there was a significant increase at the end of 2nd week and a significant decrease at the end of 4th and 6th weeks in the SOD activity. The changes in plasma antioxidant capacity were parallel to that of SOD activity with a significant and strong degree of correlation in the 4th and 6th weeks (r=0.7 and r=0.8, respectively). Serum levels of Vitamin E also increased in a time- and dose-dependent manner; the highest level was achieved in the 600 mg/kg dosing group after 6 weeks. CONCLUSIONS: Non-toxic doses of vitamin E at some levels can up-regulate SOD activity, but cumulative effect of the same doses can lead to attenuation of SOD activity and hence antioxidant defense.

Animals↗

PubMed2005

Homocysteine alterations in experimental cholestasis and its subsequent cirrhosis.

Homocysteine (Hcy), an intermediate in methionine metabolism, has been proposed to be involved in hepatic fibrogenesis. Impaired liver function can alter Hcy metabolism. The aim of the present study was to determine plasma Hcy alterations in acute obstructive cholestasis and the subsequent biliary cirrhosis. Cholestasis was induced by bile duct ligation and sham-operated and unoperated rats were used as controls. The animals were studied on the days 7th, 14th, 21st and 28th after the operation. Plasma Hcy, cysteine, methionine, nitric oxide (NO) and liver S-adenosyl-methionine (SAM), S-adenosyl-homocysteine (SAH), SAM to SAH ratio and glutathione were measured. Chronic L-NAME treatment was also included in the study. Plasma Hcy concentrations were transiently elevated by the day 14th after bile duct ligation (P < 0.01) and subsequently returned to control levels. Similar relative fluctuations in plasma Hcy were observed in BDL rats after intraperitoneal methionine overload. Plasma methionine, cysteine and nitrite and nitrate were significantly increased after bile duct ligation. SAM to SAH ratio was diminished by the 1st week of cholestasis and remained significantly decreased throughout the study. These events were accompanied by a decrease in GSH to GSSG ratio in the liver. Chronic L-NAME treatment improved SAM to SAH ratio and prevented the elevation of plasma Hcy and methionine (P < 0.05) while couldn't influence the other parameters. In conclusion, this study demonstrates alterations in plasma Hcy and liver SAM and SAH contents in precirrhotic stages and in secondary biliary cirrhosis, for the first time. In addition, we observed that plasma Hcy concentrations in BDL rats follow a distinct pattern of alteration from what has been previously reported in other models of cirrhosis. NO overproduction may contribute to plasma Hcy elevation and liver SAM depletion after cholestasis.

Analysis of Variance↗

PubMed2005

Effect of morphine on ischemia-reperfusion injury: experimental study in testicular torsion rat model.

OBJECTIVES: To investigate the effects of morphine on reperfusion injury due to testicular torsion-detorsion (T/D). METHODS: We divided 36 adult male Sprague-Dawley rats into six groups. Testicular ischemia was achieved by twisting the right testis 720 degrees counterclockwise for 1 hour, and reperfusion was allowed for 4 hours after detorsion. The baseline group was for basal normal values. The sham-operated group served as the control group. The T/D group underwent 1 hour of testicular torsion and 4 hours of detorsion. The morphine group received pretreatment with intravenous morphine sulfate (10 mg/kg) just before detorsion. The naltrexone group received an intravenous injection of naltrexone HCl (20 mg/kg) 15 minutes before detorsion. The naltrexone/morphine group received intravenous administration of naltrexone HCl (20 mg/kg) 15 minutes before detorsion and morphine sulfate (10 mg/kg) just before detorsion. RESULTS: The ipsilateral malondialdehyde levels in the T/D group were significantly greater than in the control and baseline groups. Moreover, the ipsilateral testicular malondialdehyde values in the morphine group were significantly lower than in the T/D and naltrexone/morphine groups. Also, significant decreases occurred in catalase and superoxide dismutase activities in the T/D group compared with the control and baseline groups. These values were significantly greater in the morphine group than in the T/D and naltrexone/morphine groups. The ipsilateral testes of all groups that underwent testicular torsion showed similar histopathologic changes. CONCLUSIONS: Morphine increased the ipsilateral intratesticular antioxidant markers during the reperfusion phase after unilateral testicular torsion, which was eventually reflected in lower testicular malondialdehyde levels. Furthermore, this effect was mediated through the opioid receptors.

Animals↗

PubMed2002

Induction of oxidative stress in paraquat formulating workers.

Paraquat as a bipyridyl compound is widely used as an effective herbicide worldwide. In this study, oxidative stress was investigated in blood samples of workers in a pesticide factory, formulating paraquat products for use in agriculture. Controls were age-matched workers with no history of pesticide exposure. They were measured for lipid peroxidation (LPO), antioxidant power and total thiol (SH) groups in blood. The results expressed as mean+/-SD show induction of oxidative stress in workers as revealed by increased plasma LPO (11.46+/-0.99 vs 10.11+/-0.69, P<0.001), decreased plasma antioxidant capacity (1.35+/-0.03 vs 1.54+/-0.05, P<0.001) and plasma SH groups (0.16+/-0.01 vs 0.21+/-0.01, P<0.001) in comparison to those of controls. It is concluded that paraquat-formulating factory workers have elevated LPO and decreased antioxidant power, which may put them in further consequences of oxidative stress.

Adult↗