Melatonin protects inner ear against radiation damage in rats.

OBJECTIVES/HYPOTHESIS: To examine the effects of N-acetyl-5-methoxytryptamine (melatonin) on radiation-induced inner ear damage. STUDY DESIGN: An experimental animal model. METHODS: Forty rats were randomized into five groups, as follows: 1) melatonin and then radiotherapy group (n = 8), which received intraperitoneal (i.p.) melatonin (5 mg/kg) followed by irradiation 30 minutes later; 2) radiotherapy and then melatonin group (n = 8), which received irradiation with i.p. melatonin (5 mg/kg) 30 minutes later; 3) melatonin group (n = 8), which received i.p. melatonin (5 mg/kg); 4) radiotherapy group (n = 8), which underwent only irradiation; 5) and the control group (n = 8), which received i.p. 0.9% NaCl. The medications and irradiation were administered for 5 days. All rats underwent the distortion product otoacoustic emission (DPOAE) test before and 10 days after the experiment. The middle ears of the rats were excised, and assessment of tissue alterations in the organs of Corti, spiral ganglions, and stria vascularis were compared among the groups. RESULTS: In the radiotherapy group, the DPOAE amplitudes at frequencies of 4000 to 6000 Hz were significantly decreased when compared with the controls. The DPOAE amplitudes both in the melatonin and then radiotherapy group and the radiotherapy and then melatonin group exhibited better values than they did in the radiotherapy group. Histopathological evidence of damage to the organs of Corti, spiral ganglions, and stria vascularis damage was markedly reduced in both these two groups when compared to the radiotherapy group. CONCLUSION: These results indicate that melatonin may have significant ameliorative effects on cochlear damage secondary to ionizing radiation.

Protective effect of sitagliptin against renal ischemia reperfusion injury in rats.

This study was designed to investigate the protective effects of sitagliptin on renal damage induced by renal ischemia reperfusion (I/R) in rats. For this, rats were randomly divided into four groups (n = 8): (1) sham group, in which the rats only underwent right nephrectomy; (2) right nephrectomy and left kidney ischemia (1 h) and reperfusion (24 h) group (I/R); (3) 5 mg/kg sitagliptin administrated group, per-oral once a day for two weeks; (4) 5 mg/kg sitagliptin administrated group, per-oral once a day for two weeks before left kidney I/R (n = 8). Sitagliptin-treated rats that underwent renal I/R demonstrated significant decrease in the serum urea nitrogen and creatinine and also, lipid peroxidation, total oxidant status and malondialdehyde level in the renal tissue when compared to the renal I/R group. Additionally, reduced glutathione, glutathione peroxidase, superoxide dismutase, catalase and total antioxidative capacity were significantly increased after renal I/R in sitagliptin-treated rats. Our histopathological findings were in accordance with these biochemical results. In sum, in the current study all of our results indicated that sitagliptin treatment ameliorated renal damage induced by renal I/R in rats.

Malignant pleural effusion resulting from metastasis of thyroid primaries: a cytomorphological analysis.

BACKGROUND: Malignant serous cavity effusion caused by primary thyroid cancer is extremely rare in routine clinical practice. Therefore, it is often not included in the differential diagnostic workup of patients presenting with positive effusion cytology. METHODS: The clinical features were reviewed for 6 patients seen at our institution over the last 26 years for malignant effusion resulting from metastatic thyroid cancer. The cytomorphology from 4 of these cases was also reviewed. RESULTS: All of the patients found in this study presented with malignant pleural effusion - other serous cavity effusions resulting from metastatic thyroid carcinoma were not seen. These comprised 0.25% of all patients with a known history of thyroid carcinoma and 0.67% of all malignant pleural effusions. One patient had a history of bone metastases, but all the others had no pathological evidence of distant metastatic disease prior to the pleural effusion. CONCLUSIONS: Malignant pleural effusion rarely results from a thyroid carcinoma after some latency. The diagnosis requires immunohistochemical staining as well as the pertinent clinical context.