The aim of the study was to analyze the impact of melatonin on brain oxidative stress in experimental biliary obstruction. Cholestasis was done by a double ligature and section of the extrahepatic biliary duct. Melatonin was injected intraperitoneally (500 microg/kg/day). Malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) contents were determined in the brain tissue. Biliary obstruction raised MDA and reduced GSH contents in the cortex, cerebellum, and hypothalamus areas. Moreover, the scavenger enzyme activity significantly dropped in all areas of the brain. Melatonin drastically reduced MDA concentration and enhanced GSH concentration, as well as all antioxidant enzyme activity in all brain areas obtained from the bile duct-ligated animals. In conclusion, the treatment with melatonin decreased lipid peroxidation and recovered the antioxidant status in the brain from cholestatic animals.

Objective: melatonin has been demonstrated to have active antioxidant properties in different tissues during experimental cholestasis. The aim of this research was to study myocardial oxidative stress on obstructive jaundice, and to analyze the effect of melatonin on myocardial oxidative lesions. Material and methods: we achieved cholestasis by ligature and sectioning of the main bile duct. Melatonin was administered intraperitoneally (500 µg/kg/day). We measured malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxydase (GPx) antioxidant enzyme levels in the heart tissue. Results: obstructive cholestasis increased MDA and decreased GSH as well as all antioxidant enzymes. Melatonin administration significantly decreased MDA values, and increased GSH and antioxidant enzymes on the icteric animal myocardium. Conclusions: melatonin treatment prevents oxidative stress in the cardiac tissue as induced by experimental cholestasis.

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Renal cell carcinoma is the third most common urogenital neoplasia (1). The lung and bone tissues represent the most frequent metastatic sites of renal cell carcinoma (2). Metastases in the stomach are rare and have been essentially described during autopsies (3). In this paper, we present a case of large metastatic gastric tumor whose origin was a renal cell carcinoma treated years ago. Case reportA 56 year old woman was diagnosed with stage one renal adenocarcinoma 6 years ago. She was treated with right radical nephrectomy and adjuvant chemotherapy. Three years later was diagnosed and treated of brain metastasis located in the frontal lobe, as well as in lung. A year ago, she came to our hospital for upper gastrointestinal bleeding. She presented acceptable general condition and nutritional, blood pressure 120/70 mmHg and normal cardio-respiratory auscultation. The abdomen was soft, non-tender, and no masses or organ enlargements. The analytical study revealed 6.3 g/dl hemoglobin. A thoracic abdominal TAC showed a large mass in the body and antrum stomach of 11 cm diameter without invasion adjacent structures. An upper gastrointestinal endoscopy revealed a large neoplasm from body to gastric antrum with mamelonated aspect. The patient underwent subtotal gastrectomy. The postoperative course was uneventful. The pathology and immunohistochemical study showed metastasis of kidney carcinoma ( Fig. 1). DiscussionMetastatic gastric cancer is uncommon. The most frequent location sites of cancer cells are in the body and gastric fundus, and single tumors predominate against multiple. Although generally gastric metastases account for 0.2-0.7% of stomach tumors, the metastatic tumor from carcinoma renal cells is extremely rare (3) and is an event late. The gastric metastases from renal cell carcinoma are diagnosed years after the primary tumor (4). The histological diagnoses require immunohistochemical analysis for differential diagnostic. We studied AE1/AE3 and vimentin markers, and the most recent CD10 and renal cell carcinoma markers (RCC-Ma). CD10 is a cell surface enzyme expressed in several types of normal cells including the brush border of renal tubular epithelial cells. Positivity for this marker is seen in more than 90% of renal clear carcinomas (5). RCC-Ma is a monoclonal antibody against a normal renal proximal tubule antigen. RCCMa expression is relatively specific for primary clear cell in renal carcinoma (6). In our case, the markers confirmed the diagnosis of renal carcinoma. The classic vimentin and AE1/AE3 markers were strongly positive, while CD10 and RCC-Ma showed moderately and weakly positive staining, respectively. The treatment of gastric metastases is controversial. The patients have poor prognosis with frequent extragastric metastases, and the treatment is endoscopic therapy and arterial embolization (7,8). The absence of evidence for other metastases and the presence of large tumor did not support the consideration of therapeutic endoscopy. By contrast, subtotal gastrectomy allowed acceptable...

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