27 resultados para melena


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A closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km**2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux into the deep ocean. Chlorophyll a and primary productivity doubled after fertilization, and photosynthetic quantum yield (FV/FM) increased from 0.33 to >0.40. Silicic acid (<2 µmol/L) limited diatoms, which contributed <10% of phytoplankton biomass. Copepods exerted high grazing pressure. This is the first study of particle flux out of an artificially fertilized bloom with very low diatom biomass. Net community production (NCP) inside the patch, estimated from O2:Ar ratios, averaged 21 mmol POC/m**2/d, probably ±20%. 234Th profiles implied constant export of ~6.3 mmol POC/m**2/d in the patch, similar to unfertilized waters. The difference between NCP and 234Th-derived export partly accumulated in the mixed layer and was partly remineralized between the mixed layer and 100 m. Neutrally buoyant sediment traps at 200 and 450 m inside and outside the patch caught mostly <1.1 mmol POC/m**2/d, predominantly of fecal origin; flux did not increase upon fertilization. Our data thus indicate intense flux attenuation between 100 and 200 m, and probably between the mixed layer and 100 m. We attribute the lack of fertilization-induced export to silicon limitation of diatoms and reprocessing of sinking particles by detritus feeders. Our data are consistent with the view that nitrate-rich but silicate-deficient waters are not poised for enhanced particle export upon iron addition.

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Analysis of the word lancea, of Hispanic origin after Varro, and of place names, people´s names and personal names derived from it. It confirms that the spear was the most important weapon in the Bronze Age, belonging to the iuventus and used as heroic and divine symbol. This analysis confirms also the personality of the Lusitanians, a people related to the Celts but with more archaic archaeological, linguistic and cultural characteristics originated in the tradition of the Atlantic Bronze in the II millennium BC. It is also relevant to better know the organisation of Broze and Iron Age societies and the origin of Indo-Europeans peoples in Western Europe and of pre-Roman peoples of Iberia.

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Por su carácter iterativo o frecuentativo, las formaciones verbales con sufijo –tā- (–sā-) suelen ser consideradas coloquiales. Desde este punto de vista puede resultar especialmente revelador un estudio de las mismas en Plauto y Terencio. Específicamente el propósito de este trabajo es comprobar si entre las diferencias lingüísticas reconocidas entre ambos autores se puede incluir el uso que cada uno de ellos hace de estas formaciones.

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Mucinous adenocarcinoma of the small bowel is very rare, and only few cases have been described in the literature. Association of this tumor with celiac disease has never been published. The authors report a unique case of jejunal mucinous adenocarcinoma in which a concomitant celiac disease has been histologically recognized. The difficult diagnosis, the role of laparoscopic surgery and the relationship between small bowel tumors and celiac disease are discussed. A 49-year-old man presented with recurrent melena, nausea, vomiting and anemia. A stenosis of the jejunum was documented by means of CT scan and video capsule enteroscopy. A laparoscopy was scheduled. A tumor, found in the first jejunal loop, was removed by laparoscopic surgery. Histopathology revealed a rare mucinous adenocarcinoma associated with epithelial changes secondary to celiac disease. Although small bowel tumors are rare entity, in patients with celiac disease complaining of symptoms related to altered intestinal transit or occult bleeding, an appropriate work-up should be planned for diagnosis. Mucinous type intestinal adenocarcinoma, even if never published before, could be observed. Laparoscopic surgery is often essential for the diagnosis and treatment.

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AIM: With capsule endoscopy (CE) it is possible to examine the entire small bowel. The present study assessed the diagnostic yield of CE in severe obscure-overt gastrointestinal bleeding (OOGIB). METHODS: During a 3-year period, 15 capsule examinations (4.5% of all CE in a single institution) were carried out in 15 patients (11 men; mean age 69.9 +/- 20.1 years) with severe ongoing bleeding, defined as persistent melena and/or hematochezia, with hemodynamic instability and the need for significant red blood cell transfusion. CE was carried out after non-diagnostic standard upper and lower endoscopy. The mean time from admission until CE was 4.1 +/- 4.4 days (0-15 days). RESULTS: CE revealed active bleeding in seven patients and signs of recent bleeding in four. Etiology of bleeding was correctly diagnosed in 11 patients (73.3%) (portal hypertension enteropathy, three patients; subepithelial ulcerated lesion, two patients; angiodysplasia, two patients; jejunal ulcer with visible vessel, one patient; multiple small bowel ulcers, one patient; jejunal tumor, one patient; jejunal mucosa irregularity with adherent clot, one patient). One patient (6.7%) had active bleeding but no visible lesion. As a consequence of the capsule findings, specific therapeutic measures were undertaken in 11 patients (73.3%) with five managed conservatively, four endoscopically and two surgically. Two patients experienced bleeding recurrence. One of them, with a probable small bowel tumor, refused any other interventions. CONCLUSIONS: CE is useful in patients with severe OOGIB by providing positive findings in the majority of patients, with subsequent impact on therapeutic procedures.