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C Rivas

Publications and source records attributed to C Rivas.

At least 145 records · Page 8Linked to original sources
PubMed1982

[Apropos of the 2nd case of cutaneous granuloma caused by Mycobacterium marinum in Uruguay].

A new, second uruguayan case of cutaneous granuloma by Mycobacterium marinum is presented. The patient a 31 years old white man from Montevideo city had two granulomatous and ulcerated lesions on the right knee, secondary to wounds suffered with mussels' shells 5 years before while cleaning his boat in saline waters close to our Rio de la Plata river. Diagnosis was made by finding the typical acid fast organisms in the lesions, the isolation of the agent in cultures and through experimental inoculation of laboratory animals. Metastatic nodular lesions were observed in hamsters (Mesocricetus auratus) after intratesticular inoculation. A clear improvement was obtained by local heat confirming previous observations.

Adult↗
PubMed1979

Effects of captivity on glucose tolerance in dogs.

Captivity decreased tolerance to glucose and increased blood serotonin levels in 6 normal dogs investigated. Return to freedom brought normalization in the glucose tolerance test and reverted blood serotonin to control levels.

Animals↗
PubMed1975

The effect of serotonin (5-HT) on insulin secretion.

The present study was aimed at observing the effect on insulin secretion of serotonin (5-HT) administered intraportally to anesthetized adult dogs. The influence of 5-HT on insulin release was also studied in mouse pancreatic islets isolated by a collagenase method. In the in vivo studies, 6 mg of 5-HT rapidly injected in the portal vein of dogs induced hypoglycemia, and a significant increase of immunoreactive insulin plasma levels (IRI) in blood samples taken from the pancreatoduodenal vein. The phenomenon was registered throughout three consecutive 10 min periods after serotonin administration. With 3 mg of 5-HT the IRI increases were not observed. When serotonin was slowly infused at doses of 3 and 6 mg, no increases of IRI were recorded. In the in vitro studies, 5-HT at 100 mug/ml stimulated the output of insulin in the presence of a low concentration of glucose (0.6 mg/ml); when the islets were incubated with glucose at a higher concentration (3.0 mg/ml) there was a lower insulin release in the presence of serotonin (100 mug/ml) than that obtained with glucose alone at the same concentration (3.0 mug/ml). The results obtained suggest that serotonin stimulates insulin release under certain conditions in the intact dog and also in the isolated pancreatic islets of the mouse incubated in vitro.

Animals↗
PubMed1974

Nuclear bodies in Hodgkin's disease.

Nuclear bodies in Hodgkin's disease were found in four out of twenty-one cases studied under the electron microscope. They were present in histiocytes, vascular endothelial and lymphoid cells. They were found in lymphoic blastoid cells (Hodgkin's cells) but not in Reed Sternberg cells. Their morphology was characterized by two predominant patterns: fibrillar and granular. The current concepts of morphology and pathogensis of these formations are discussed.

Biopsy↗
PubMedDate not supplied

Phenotypic expression of histocompatibility antigens in human primary tumours and metastases.

HLA class I and II expression was studied on 244 (177 primary and 67 metastatic) solid human tumours of different origin. Alkaline immunophosphatase (APAAP) and immunoperoxidase were used on cryostatic sections to stain MHC antigens. Monomorphic MoAbs were used against class I heavy chain, beta 2-microglobulin, DR, DQ and DP molecules. Class I expression was homogeneous on colon, melanoma and epidermoidal primitive tumours. Loss of HLA class I antigens was more frequent on basal cell carcinomas and sarcomas and was related to tumour differentiation on larynx carcinoma. Class I expression was heterogeneous on breast, larynx and stomach primitive neoplasias. Class I negative tumours were more frequent on metastatic than on primitive melanomas. Divergence of class I between primary tumours and autologous metastases was observed on melanomas, larynx and colorectal carcinomas. Class II expression was heterogeneous on all tumours and in a large number of cases was associated with high intensity of leukocytic infiltrate. HLA-DR expression was higher than HLA-DP and HLA-DQ (DR greater than DP greater than DQ) and was related to tumour progression. Four human tumour cell lines were modulated with recombinant interferon-gamma for HLA class I and II antigens. Different HLA profiles were obtained: increased class I and II expression, increased class II or a low response. Finally, class I genes from 22 tumours were compared with autologous normal cells by Southern blot analysis: 12 tumours were class I positive and 10 negative. No clear differences in RFLP were observed that could be associated with class I rearrangement. The results are discussed in relation to the role that histocompatibility antigens may play in tumour progression and invasiveness.

Genes, MHC Class I↗
PubMedDate not supplied

Sylvatic American trypanosomiasis in Argentina. Trypanosoma cruzi infection in mammals from the Chaco forest in Santiago del Estero.

Trypanosoma cruzi infection in sylvatic mammals of the quebracho woods of the eastern part of Santiago del Estero province, Argentina, was studied from October 1984 to December 1987. 301 mammals of 20 different species were caught. T. cruzi, characterized biologically and biochemically, was isolated by xenodiagnosis from 23 of 72 (32%) Didelphis albiventris opposums, 2/36 (5.5%) Conepatus chinga skunks, and one ferret (Galictis cuja). 53 opossum refuges were located and triatomine bugs were found in 2 of them: one male Triatoma infestans, infected with T. cruzi, and 5 uninfected nymphs of T. sordida, had all fed on opossum blood. Electrophoretic zymogram patterns of the T. cruzi populations isolated from opossums and skunks were similar to isoenzyme profiles already described for populations isolated from infected humans in Argentina. The small number of triatomines found in the opossum refuges seems inadequate to account for the prevalence of T. cruzi infection recorded for these mammals, so other possible contaminative routes of infection should be investigated.

Animals↗
PubMedDate not supplied

Ultrastructure of 26 cases of Ki-1 lymphomas: morphoimmunologic correlation.

Twenty-six cases of high-grade lymphomas with activation markers (CD30) classified and immunophenotyped according to the Kiel classification were studied to determine their fine structural features. Transmission electron microscopy showed in 17 cases anaplastic nuclear and cytoplasmic changes identical to those observed in Hodgkin's disease, it being impossible to determine by the morphology a B, T, or null nature. Four high-grade B-centroblastic and immunoblastic cases and five T-pleomorphic cases showed nuclear changes and cytoplasmic differentiation that suggested a T or B nature. An immunogold-labeling technique showed CD30-positive particles primarily in the Golgi complex and occasionally in the cell membrane.

Antigens, Differentiation↗