Renal ischemia as well as oxygen metabolites play an important role in renal injury during myoglobinuric acute renal failure (ARF). On the other hand, flavonoids, a diverse group of constituents naturally occurring in plants, have a strong antioxidative activity, and have been implicated in vascular relaxation. In this study the protective effect of a new bioflavonoid proanthocyanidin-BP1 (BP1), extracted from seeds of grapes, was evaluated in glycerol-induced ARF in rats. Stereological methods were used to quantify changes in renal morphology associated with ARF. Volume density of tubular lumen and intratubular cast formations, nuclear parameters (area, diameter, volume) of epithelial cells in the cortical proximal tubules, and glomerular parameters (surface area, diameter, volume, perimeter) were estimated on kidney sections of rats treated either with 50% glycerol (8 mL/kg i.m.) alone. BP1 (20 mg/kg i.p.) in addition to glycerol, or BP1 alone. It was noted that the volume density of tubular lumen and cast formations were significantly lower (p < 0.001) in kidneys of the rats treated with BP1 in addition to glycerol, compared with those treated with glycerol alone. There were no significant differences in glomerular and nuclear parameters between glycerol treated, and BP1 in addition to glycerol treated rats. Renal function was significantly improved in rats treated with BP1 in addition to glycerol. The results suggest that BP1 is a protective agent in glycerol model of ARF. This effect is probably due to the antioxidative activity of BP1 and reduced toxicity of myoglobin in renal tissue. Moreover, it is possible that the ability of BP1 to protect the kidney is dependent upon renal vascular relaxation. The potential beneficial effects of bioflavonoid-BP1 demonstrated in experimental ARF could be considered in therapy of myoglobinuric ARF.

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In the pathogeneses of recurrent tonsillitis (RT) and tonsillar hypertrophy (TH), different immunological mechanisms are involved. Dipeptidyl peptidase IV (DPP IV) and aminopeptidase N (APN) participate in the regulation of the immune response during inflammation. In this study, the localization of DPP IV and the enzymatic activities of DPP IV and APN in 32 patients, 13 with RT and 19 with TH, who underwent tonsillectomy were investigated. The localization of DPP IV in tonsils was studied using histochemical and immunohistochemical methods. The enzymatic activities of DPP IV and APN in tonsillar lymphocytes and the patients' sera were determined kinetically at 37°C using Gly-Pro-p-nitroanilide (for DPP IV) and Ala-pnitroanilide (for APN) as chromogenic substrates. In samples from both RT and TH patients, DPP IV was found to localize mainly in extrafollicular areas of tonsillar tissue in a pattern corresponding to the T-cell distribution. Significantly higher (P < 0.001) levels of DPP IV and APN activities in sera from patients with TH than in sera from patients with RT were found. A correlation of DPP IV activities in sera and tonsillar lymphocytes from patients with TH was also found (r ‫؍‬ 0.518; P < 0.05). Moreover, the results show that DPP IV and APN activities in sera decreased significantly with age. Tonsillar lymphocytes demonstrated a wide range of DPP IV and APN activities, without significant differences between the investigated groups. The results of this study show that the localization of DPP IV does not depend on the type of tonsillitis, whereas the variety in levels of DPP IV and APN activities in sera of patients with TH and RT suggests different patterns of participation of antigen-stimulated tonsils in the immune system.

An increased serum DPP IV activity was observed in TH patients compared with both RT patients and controls before tonsillectomy. After tonsillectomy, all activities were similar. The results suggest that serum DPP IV activity may have potential as a diagnostic marker for patients with TH.