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The Atacama Desert, on the western margin of the Central Andes, hosts some of the world's largest porphyry copper deposits (PCDs). Despite a hyperarid climate, many of these PCDs have undergone secondary "supergene" enrichment, whereby copper has been concentrated via groundwater-driven leaching and reprecipitation, yielding supergene profiles containing valuable records of weathering and landscape evolution. We combine hematite (U-Th-Sm)/He geochronology and oxygen isotope analysis to compare the weathering histories of two Andean PCDs and test the relative importance of climate and tectonics in controlling both enrichment and water table movement. At Cerro Colorado, in the Precordillera, hematite precipitation records prolonged weathering from ~31 to ~2 Ma, tracking water table descent following aridity-induced canyon incision from the late Miocene onward. By contrast, hematite at Spence, within the Central Depression, is mostly younger than ~10.5 Ma, suggesting exhumation ended much later. A heavy oxygen isotopic signature for Spence hematite suggests that upwelling formation water has been an important source of groundwater, accounting for a high modern water table despite persistent hyperaridity, whereas isotopically light hematite at Cerro Colorado formed in the presence of meteoric water. Compared with published paleo-environmental and sedimentological records, our data show that weathering can persist beneath appreciable post-exhumation cover, under hyperarid conditions unconducive to enrichment. The susceptibility of each deposit to aridity-induced water table descent, canyon incision and deep weathering has been controlled by recharge characteristics and morphotectonic setting. Erosional exhumation, rather than aridity-induced water table decay, appears to be more important for the development of supergene enrichment. [ABSTRACT FROM AUTHOR]

The treatment of acute and recurrent variceal bleeding is best accomplished by a skilled, knowledgeable, and well-equipped team using a multidisciplinary integrated approach. Optimal management should provide the full spectrum of treatment options including pharmacologic therapy, endoscopic treatment, interventional radiologic procedures, surgical shunts, and liver transplantation. Endoscopic therapy with either band ligation or injection sclerotherapy is an integral component of the management of acute variceal bleeding and of the long-term treatment of patients after a variceal bleed. Variceal eradication with endoscopic ligation requires fewer endoscopic treatment sessions and causes substantially less esophageal complications than does injection sclerotherapy. Although the incidence of early gastrointestinal rebleeding is reduced by endoscopic ligation in most studies, there is no overall survival benefit relative to injection sclerotherapy. Simultaneous combined ligation and sclerotherapy confers no advantage over ligation alone. A sequential staged approach with initial endoscopic ligation followed by sclerotherapy when varices are small may prove to he the optimal method of reducing variceal recurrence. Overall, current data demonstrate clear advantages for using ligation in preference to sclerotherapy. Ligation should therefore he considered the endoscopic treatment of choice in the treatment of esophageal varices. [ABSTRACT FROM AUTHOR]

Cryostorage of nonhuman primate embryos by time-consuming slow-cooling methods is often limited to early cleavage stages. Effective rapid-cooling methods have been developed for many species and represent valuable tools for laboratory- and field-based studies of nonhuman primate reproductive biology. However, few rapid-cooling protocols have been applied to nonhuman primate embryos in terms of comparing various developmental stages. Here we compare slow cooling vs. two- and three-step rapid cooling of two-, four-, and eight-cell Macaca fascicularis (Mf ) embryos. Rapid cooling was conducted in open pulled straws (OPS) using cooling solutions containing reduced quantities of ethylene glycol (EG) and supplemented with either of two high-molecular-weight polymers, ficoll and dextran. The survival of the slow-cooled embryos, but not the rapid-cooled embryos, was independent of embryonic stage at cryostorage. Slow cooling was associated with greater cell survival (82%) post thaw compared to warming following rapid cooling (18–29%). Slow cooling resulted in a high proportion of embryo survival (18/20; 90%) and cleavage (15/18; 83%) post thaw. Rapid cooling resulted in significantly reduced percentages of embryo survival (26–32%) and embryo cleavage in culture (29–38%) after warming. Conventional slow cooling was more effective than the rapid-cooling protocols employed in this study for cryopreservation of early-cleavage-stage Mf embryos. Am. J. Primatol. 58:169–174, 2002. © 2002 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The article presents a case of a 63-year old woman with drug-induced hepatitis. The patient had an episode of melena on the second hospital day. It was revealed at upper gastrointestinal endoscopy, that her entire esophagus was black and friable. She was diagnosed of having acute esophageal necrosis.