Fecal short-chain fatty acids at different time points after ceftriaxone administration in rats.

Short-chain fatty acids (SCFAs) are major products of the microbial fermentation of dietary fiber in the colon. Recent studies suggest that these products of microbial metabolism in the gut act as signaling molecules, influence host energy homeostasis and play major immunological roles. In the present study, defined the long-term effects of ceftriaxone administration on the fecal SCFAs concentration in Wistar rats. Ceftriaxone (300 mg/kg, i.m.) was administered daily for 14 days. Rats were euthanized in 1, 15 and 56 days after ceftriaxone withdrawal. Caecal weight and fecal concentration of SCFAs by gas chromatography were measured. Ceftriaxone administration induced time-dependent rats' caecal enlargement through accumulation of undigestable substances. In 1 day after ceftriaxone withdrawal, the concentrations of acetic, propionic, butyric acids and total SCFAs were decreased 2.9-, 13.8-, 8.5-, 4.8-fold (P < 0.05), respectively. Concentration of valeric, isovaleric and caproic acids was below the detectable level. That was accompanied by decreased 4.3-fold anaerobic index and increased the relative amount of acetic acid (P < 0.05). In 56 days, concentration of SCFAs was still below control value but higher than in 1 day (except propionic acid). Anaerobic index was lower 1.3-fold (P < 0.05) vs. control. Conclusion: antibiotic therapy induced long-term disturbance in colonic microbiota metabolic activity.

[The effect of ultraviolet on the structural-functional characteristics of mouse thymocytes]. / Vplyv ul'trafioletu na strukturno-funktsional'ni kharakterystyky tymotsytiv myshei.

The changes of peculiarities thymocytes membranes after the UV actions on the suspension cells were investigated. The POL intensivity; content the carotene, vitamins A,E and its metabolites were determined. The state of membrane lipids and proteins was observed by fluorescent zondes. After 15 min of UV action form of the humoral activity products of POL was increased; the redox system of vitamin E was mobilized; the membranes proteins was opened; the neutral lipid fraction in membranes was decreased, and its polarity was increased. After 25 min of UV action was observed: the stimulation of the first and second steps of POL; decreased of AO activity; more opened of membranes proteins; more increased of polarity lipids and reform of lipofility of membranes. This changes lay in the base of activity and passivity of thymocytes by UV.