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The clinical utility of an ELISA test with monoclonal antibodies to detect antigen of Entamoeba histolytica in feces was evaluated in 150 patients with gastrointestinal symptoms. Each subject was examined by rectosigmoidoscopy with rectal smear and/or a triple stool search for ova-bacteria-parasite (OBP); in addition, one stool sample was collected for the ELISA test. All the tests were independent and double blind. E. histolytica was detected by OBP and/or rectosigmoidoscopy in 66 patients; 61 patients had other parasites; and in 23, no parasites were identified. Of all patients, 116 were positive for the ELISA test. Of these, E. histolytica was identified in 52. In 47, other parasites were identified and in 17, no parasites were found. The ELISA test with a monoclonal antibody against E. histolytica antigen showed higher sensitivity than the standard diagnostic methods: the ability to detect the presence of E. histolytica antigen regardless of the destruction of the parasite or of the error due to misidentification of the parasite resulting from faulty preparation of the samples.

"A major contribution to the scholarship of gender and sexuality in the Caribbean."--A. Lynn Bolles, University of Maryland This volume provides an engaging interdisciplinary approach to the study of gender and sexual relations in the Caribbean. Essays from sociological, literary, historical, and political science approaches cover the Hispanic-, French-, and English-speaking Caribbean areas and address topics such as sexuality, homosexuality, culture, the body, the status of women, and the wider social relations that inform these subjects. Contents Exploring the Intersections of Gender, Sexuality, and Culture in the Caribbean: An Introduction Part 1. Theoretical Mediations on Gender in the Caribbean 1. Theorizing Ruptures in Gender Systems and the Project of Modernity in the Twentieth Century Caribbean, by Violet Eudine Barriteau 2. The Globalization of the Discourse on Gender and Its Impact on the Caribbean, by Hilbourne Watson 3. Caribbean Masculinity: Unpacking the Narrative, by Linden Lewis Part 2. The Political Terrain of Gender and Sexuality 4. A Blueprint for Gender in Creole Trinidad: Exploring Gender Mythology through Calypsos of the 1920s and 1930s, by Patricia Mohammed 5. Popular Imageries of Gender and Sexuality: Poor and Working-Class Haitian Women's Discourses on the Use of Their Bodies, by Carolle Charles 6. "The Infamous Crime against Nature" Constructions of Heterosexuality and Lesbian Subversions in Puerto Rico, by Elizabeth Crespo-Kebler Part 3. Sexual Orientation and Male Socialization in the Caribbean 7. The Role of the Street in the Socialization of Caribbean Males, by Barry Chevannes 8. Masculinity and Power in Puerto Rico, by Rafael Ramirez 9. Queering Cuba: Male Homosexuality in the Short Fiction of Manuel Granados, by Conrad James Part 4. Gender, Sexuality, and Historical Considerations 10. Struggling with a Structure: Gender, Agency, and Discourse, by Glyne Griffith 11. "It Hurt Very Much at the Time" Patriarchy, Rape Culture, and the Slave Body-Semiotic, by Joseph C. Dorsey Linden Lewis is associate professor of sociology and anthropology at Bucknell University and the author of numerous articles on the Caribbean.

En este texto, el almuerzo organizado por Diego en honor de David es una de las escenas clave del relato.1 Como Bejel adelanta en su ensayo, el pasaje es de suma importancia para la tarea del interpretador, ya sea por las paradojas que presenta o por las pistas que ofrece en la elucidaci?n de las intenciones del texto (62). Es para Diego la ofrenda m?xima de su amistad, y para David un reconocimiento a su valor personal, y la se?al probable de que la frivolidad de Diego asume un cariz tal vez m?s sensato o pr?ctico, aunque no menos extraordinario. En la lectura de este "notorio fest?n o "almuerzo lezamiano" hay, pues, estas significaciones: el voto de buena voluntad por parte de Diego; la posibilidad para David de una experiencia est?tica de iniciaci?n; una constataci?n de lo que Sant? llama "ret?rica de la reconciliaci?n cubana", a trav?s de la comuni?n de la mesa; la ceremonia que honra a Jos? Lezama Lima.2 Este trabajo desarrolla un an?lisis que se fundamenta en la explicaci?n del almuerzo en otras tres vertientes, que se figuran por parte de Diego en el prop?sito pol?tico, el lucimiento esteticista y el veh?culo de revelaci?n cultural. Aunque podr?an aislarse cada uno de los objetivos menciona? dos, estas tres coordenadas se presentan vinculadas en la ceremonia del convite, en un acto m?ltiple de asalto por parte de Diego contra y frente el sentir social e ideol?gico de David, en

Agates from basalts display bands consisting of chalcedony fibers with low-trace-element content that repeatedly alternate (Wang and Merino, 1990) with bands consisting of twisted, very fine fibers high in trace dements. This association of repetitive features is a striking case of selforganization, a class of processes in which the system generates its features through its own dynamics (Nicolis and Prigogine, 1977). We summarize here a new crystal growth model that accounts for the genesis of each texture and compos i t ion , their associa t ion , and their systematic alternation. Petrographic, microstructural, chemical, isotopic, and other agate data are given by Michel-Lrvy and Munier-Chalmas (1892), Correns and Nagelschmidt (1933), Frondel (1962, 1978), Fallick et al., (1985), Harris (1989), Fl6rke et al., (1984), Cady et aL, (1993), Heaney (1993), and others.

In reaction-transport models of petrological processes in rocks exhibiting replacement, reactions should be balanced on volume, and mineral reaction rate laws should contain a crucial dependence on stress. Existing models neglect this (e.g., Steefel and Lasaga, 1992); they ought to be improved to take account of authigenic textures. Widespread pseudomorphic replacement in rocks of all types follows from the facts that space in rocks is limited, that growth of new mineral grains would develop huge stress if adjacent grains did not simultaneously dissolve under the pressure developed by the growing grains, and that viscosity of rocks is probably enormous on the time scales of replacement reactions. Available experimental mineral rates of dissolution and growth miss the stressdependence of rates that operates in mineral reactions in rocks. This may underlie the apparent disagreement (Brantley, 1992) between laboratory rates and field-derived rates.

Renal transplantation for terminal renal failure as a result of scleroderma (progressive systemic sclerosis [PSS]) seems justified if other organs have not been severely damaged by the disease. The recurrence of PSS in the graft, not observed in early reports, appears to have caused the rapid failure of a cadaveric graft in a forty year old woman with acute PSS. A similar case of rapid PSS recurrence in the transplant has been recently reported by others [7]. A more aggressive pattern of PSS seems to differentiate these two patients in whom recurrence was observed from four previous patients with long-term graft functions. The possibility of rapid renal transplant loss should be considered in the selection and prognosis of acute PSS patients.

Of 125 patients with postsurgical acute tubular necrosis, 87 died, 34 regained clinical normal renal function, and 4 survivors (9.5%) were left with severe permanent renal failure, two of whom required chronic dialysis and transplantation. Preoperatively these 4 patients had normal renal function. The 4 patients were above age 60, two had undergone methoxyflurane anesthesia, and nephrotoxic antibiotics were used in all. The incidence of permanent renal failure is much higher than ever reported and may reflect the survival of patients who previously died because of less ideal dialysis. We believe that the cause of this permanent lesion is multifactorial, including age (over 60 years), nephrotoxic antibiotics (particularly cephalothin and gentamicin sulfate), and nephrotoxic anesthetic (methoxyflurane) agents. This combination of factors should be avoided whenever possible.

Oral methionine is noncomatogenic in normal dogs, but it is consistently comatogenic in dogs with portacaval shunts in the presence of elevated ammonia levels. Such action appears to be enhanced by the ammonia itself, since relatively small doses of oral methionine can induce coma when baseline levels of ammonia are above 1,000 mug/100 ml; much higher doses are nesessary for near normal ammonemia. The methionine-induced coma closely reproduces the clinical and electroencephalographic picture of coma in other canine models. Oral methionine does not significantly increase the ammonia levels, but its action is probably mediated by the release of methanethiol (and other less active compounds) from the bowel. Methanethiol levels tend to increase in proportion to the amount of methionine administered, and its comatogenic action may be amplified, up to one hundredfold, by high ammonia levels. Methanethiol levels in comatose patients and the concept of the synergistic effect with ammonia may lead to a clearer understanding of certain enterogenous and dietetic forms of hepatic encephalopathy in cirrhotic patients. The lowering of ammonia levels by hemodialysis or methanethiol levels by activated charcoal hemoperfusion, as attempts to reverse such forms of coma, warrants further investigation.

Five life threatening complications of percutaneous femoral vein catheterization for hemodialysis (Shaldon Technique) are presented. They occurred over a period of five years during which 700 uneventful catheterizations were carried out. In three instances femoroiliac vein thrombosis occurred, and on one occasion this was complicated by pulmonary embolism. In two other instances perforation of the inferior vena cava occurred with profuse bleeding. These complications can be aboided by early removal of the catheters after dialysis and by cautiously manipulating the wireguide when resistance or obstruction is encountered during insertion.

Renal transplantation for terminal renal failure as a result of scleroderma (progressive systemic sclerosis [PSS]) seems justified if other organs have not been severely damaged by the disease. The recurrence of PSS in the graft, not observed in early reports, appears to have caused the rapid failure of a cadaveric graft in a forty year old woman with acute PSS. A similar case of rapid PSS recurrence in the transplant has been recently reported by others [7]. A more aggressive pattern of PSS seems to differentiate these two patients in whom recurrence was observed from four previous patients with long-term graft functions. The possibility of rapid renal transplant loss should be considered in the selection and prognosis of acute PSS patients.

Late onset (3-7 yrs) post-transplant renal hypertension is usually an indication of chronic, irreversible renal damage, and is a poor prognostic sign. In a small percent of patients (10%) however, hypertension can persist for years in conjunction with excellent renal function, and the absence of any known causes of early or late hypertension. This primary hypertension does not seem related to the recipient's pre-transplant blood pressure nor to the original renal disease. Rather, the high incidence of essential hypertension in the respective living related donor suggests that either a hypertensive diathesis exists, common to donor and recipient, or a transplantable factor inherent to the graft, or both causes, predispose to late onset primary hypertension.

Mongrel dogs received transplanted kidneys following total nephrectomy. The whole blood was centrifuged to separate out the lymphocytic fraction, which was tagged with 51Cr. Renal accumulation of 51Cr was followed using imaging detectors. All allograft rejections were accompanied by a simultaneous rise in the count rate. Labeled lymphocytes can be used to detect canine renal rejection, and the authors feel that this technique can be applied to man.

Collections and dissections of black flies from human subjects were carried out over a 13-month period at two onchocerciasis-endemic sites in Guatemala. Simulium ochraceum comprised 87% of all flies collected. Populations of this species peaked during the first part of the dry season in November, while populations of S. metallicum, S. callidum and S. downsi were highest during the rainy season from June–October. Diurnal patterns of host-seeking activity were most pronounced for S. ochraceum, with a sharp peak occurring between 0700 and 0900 hours each day. Parous ratio was lowest at this time (27%), and rose to a peak of 63% between 1200 and 1400 hours each day. Eighty-eight percent of all parous S. ochraceum collected during 1200–1400 hours had large dilatations in the tunica of the ovarioles resulting from recent oviposition, thus indicating that this species oviposits in the morning and immediately seeks the subsequent blood meal. Parous biting density (the product of the total number of flies biting at a given time and the corresponding parous ratio) showed two distinct diurnal peaks, one in the early morning characterized by low parous ratio and high total number of flies, and the other in the early afternoon characterized by high parous ratio and low total number of flies. Moreover, the diurnal pattern of biting density of filaria-infected S. ochraceum was similar to that of parous biting density.

The amino acid sequence for the two subunits of the glutamate synthase of Escherichia coli K-12 was compared to the protein sequences compiled in the National Biomedical Research Foundation databank. Similarities were detected between the small glutamate synthase subunit and three members of the flavin-containing pyridine nucleotide-disulphide oxidoreductase superfamily, and also with three members of a lactate dehydrogenase family. Two segments in this glutamate synthase subunit showed similarity to regions previously proposed as part of dinucleotide-binding sites in some members of these two families. Similarity can be extended if the predicted secondary structure is considered. Based on these data, residues 148-260 and 289-409 in the small GOGAT subunit are proposed as dinucleotide-binding regions. Comparison of the amino acid sequence of the large glutamate synthase subunit with the glutamine phosphoribosylamine:pyrophosphate phosphoribosyltransferases of B. subtilis and E. coli revealed a significant similarity between the amino termini of these three enzymes. In these last two amidotransferases, the glutamine-binding site has been located in their amino-terminal region. The comparison with a second group of glutamine amidotransferases did not show any significant global similarity with the large glutamate synthase subunit. However, this polypeptide contains a small segment that shares similarity with a 13-amino acid segment proposed as part of the glutamine-binding site in this second group of amidotransferases.

The gastroduodenal mucosa has a negative electrical potential with regard to the blood stream, as measured by a potentiometer connected to an intravenous and an intragastric electrode. The intragastric electrode can be positioned on various points of the gastroduodenal surface under direct vision through the forceps channel of the gastroduodenoscope. The values of potential differences were determined in various areas of the stomach and duodenum of normal humans and also over gastric ulcers, duodenal ulcers, gastritis and gastric erosions. A deflection of the potential difference value toward zero characterizes any disruption of the normal mucosa, even if only a few millimeters in diameter. Localized reproduce localized potential difference deflections. Atrophic lesions are represented by larger areas of abnormal potential difference levels. The direct multiple determinations of potential differences over mucosal areas in which lesions are suspected is a useful, simple tool for more objective gastroduodenoscopic diagnoses.