Supplementation with L-arginine affects its metabolizing pathways in rat liver subjected to bile duct ligation

Liver cholestasis is known to accompany several major liver disorders and is adequately mimicked in rats by ligation of the bile duct (BDL). L-arginine is a semi-essential amino acid which is involved in several important metabolic pathways that are significantly affected during cholestasis. This study was conducted in order to contribute to the understanding of the enrolment of L-arginine supplementation in cholestatic liver function. This was carried out by estimation of serum and liver tissue arginase activity, along with liver tissue citrulline, nitric oxide (NO) and polyamine concentrations. Rats subjected to BDL were treated for nine days with L-arginine (150 mg/kg) or remained without any treatment. Animals from two control groups were either subjected to medial laparotomy (sham/opened group) or were without any surgical treatment and received only L-arginine. Application of L-arginine prevented a significant increase in plasma bile acid and bilirubin concentrations, as well as enzyme biochemical markers that were increased after BDL. It is worth mentioning that L-arginine was able to cause a decrease in arginase activity and liver tissue NO concentrations that were found to be significantly altered during cholestasis. On the other hand, the changes occurring in the concentration of liver polyamines (putrescine, spermidine and spermine) and the activity of polyamine metabolizing enzymes were not notably affected by the administered L-arginine. The results of the present study revealed that exogenous L-arginine was able to ameliorate or prevent changes occurring in its metabolism in liver during cholestasis.

[The monitoring of air pollution in a hospital environment using quantitative air biology methods]

The methodology of quantitative aerobiological control is described and the results of measurements of the intensity and character of air contamination are commented for several places of general surgical ward. The importance of such a control is stressed in the context of general efforts to improve the quality of air in hospitals, to prevent air contamination and decrease the incidence of aerogenic infections. The results of those measurements show that the intensity of air contamination is corresponding to the total volume of physical activity in a milieu. In some very delicate hospital areas (dressing units and operating theatres), the concentration of aerosol sometimes exceeds its permitted level and if this is a case, it is advised to take all possible measures of protection to prevent air contamination and aerogenic infections. It is also found out that at the very beginning of physical activity, there is predominance of relatively big aerosol fractions in air, but soon this predominance is diminished because of the elimination of those fractions by sedimentation.