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Biomedical subjects

R Barrera

Publications and source records attributed to R Barrera.

At least 55 records · Page 3Linked to original sources
PubMed1992

Evaluation of total protein content in tears of dogs by polyacrylamide gel disk electrophoresis.

Concentration of total proteins was measured and sodium dodecyl sulfate-polyacrylamide gel disk electrophoresis was performed on tear and plasma samples obtained from 26 healthy dogs, and the results were compared. Mean +/- SEM concentration of total proteins in tears was 0.63 +/- 0.04 g/dl, and significant effects of age or gender were not found. The protein composition of tears in dogs was complex, and bands from light and heavy chains of immunoglobulins were identified by electrophoresis.

Age Factors↗
PubMed1990

[Autoimmune polyglandular syndrome. Clinical experience in 21 cases].

The autoimmune polyglandular syndrome is characterized by the association of 2 or more endocrine disorders of autoimmune origin which may coexist with autoimmune disorders in other organs. Roughly 25% of patients with an autoimmune endocrinopathy show evidence of autoimmune disease elsewhere. We report 21 patients with autoimmune polyglandular syndrome classified according to Neufeld.

Adult↗
PubMed1990

Results and histological development of various surgical techniques for correcting eversion of the third eyelid in dogs.

An experimental study was made of 20 dogs in order to compare various surgical techniques used to correct eversion of the third eyelid, namely resection of most of the cartilage, resection of the central portion of the cartilage, and cartilage homotransplantation. An analysis was made of histological results obtained 45 days after operation, the most satisfactory result being recorded for homotransplantation of the third eyelid cartilage.

Animals↗
PubMed1989

Adsorptive endocytosis of lysosomal enzymes by human fibroblasts: presence of two different functional systems that deliver an acid hydrolase to lysosomes.

Endocytosis of human spleen beta-glucuronidase by human fibroblasts can be completely impaired by the competitive inhibitor mannose 6-phosphate or by pretreatment with acid phosphatase or endoglycosidases H or F. However, endocytosis of bovine spleen and liver beta-glucuronidase is partially impaired by the same treatments, suggesting that the bovine enzyme contains two endocytosis recognition markers located in separate enzyme domains. The mannose 6-phosphate recognition marker seems to be responsible for approximately 23% of the bovine enzyme endocytosis. The existence of two lysosomal endocytosis systems in human fibroblasts is supported by the following facts: (a) the rate of endocytosis of mannose 6-phosphate-containing human beta-glucuronidase was not affected by the presence of high levels of the bovine enzyme (which has only the other marker). (b) Anti-215K mannose 6-phosphate receptor antibodies selectively impair the endocytosis of the beta-glucuronidase containing mannose 6-phosphate. (c) Weak bases exert a differential effect on human and bovine endocytosis. beta-Glucuronidase internalized by either system is targeted to secondary lysosomes of human beta-glucuronidase-deficient fibroblasts, where it is able to degrade accumulated glycosaminoglycans. These results suggest that human fibroblasts have two different and independent endocytic systems for targeting of acid hydrolases to lysosomes.

Ammonium Chloride↗
PubMed1986

Glucose tolerance and the insulin response in recently drinking alcoholic patients: possible effects of withdrawal.

To investigate possible effects of withdrawal on carbohydrate metabolism in chronic alcoholic patients, intravenous glucose tolerance tests were performed in three periods in 11 alcoholic patients: early abstinence (less than three days), early abstinence plus ethanol (1 g/kg/BW IV), and late abstinence (three weeks later). According to liver biopsy results and laboratory tests, patients were classified as a group with liver damage (four cases) and a group without it (seven cases). In the group without damage, glucose tolerance expressed as K% and compared to a control group, was significantly decreased in early and late abstinence but not after the infusion of ethanol. Cases with damage also had glucose intolerance at admission. Plasma insulin levels after the glucose load were significantly lower at ten and 30 minutes in the group without damage, in early or late abstinence. They were normal in the presence of ethanol. Patients with liver damage presented higher basal and postglucose plasma insulin concentrations. It was concluded that glucose intolerance in alcoholic patients is a common finding that occurs in the presence or absence of liver damage. In cases with liver damage it seems to be due to peripheral insulin resistance. In those without damage it is related to low peripherovenous insulin levels.

Acute-Phase Proteins↗
PubMedDate not supplied

Characterization of renal damage in canine leptospirosis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting of the urinary proteins.

Canine leptospirosis is a zoonotic disease that can cause interstitial nephritis. As a consequence of the renal damage, proteinuria may occur. To determine the urine protein pattern in the disease we performed sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) on the urine from 10 dogs with leptospirosis and 20 healthy dogs. Western blotting analysis of the urine samples with antibodies against canine IgG and IgA was also performed to identify these immunoglobulins in the urine. Urine electrophoresis showed three new bands in the dogs suffering from leptospirosis. Only two of the dogs with leptospirosis showed detectable concentrations of IgG and IgA in urine, while a third animal showed IgG alone. The study showed a 36.7% increase in the excretion of low molecular weight proteins in dogs with leptospirosis but almost no change in the high molecular weight protein pattern. These results, together with the low number of animal with detectable concentrations of IgG and IgA in the urine, support the view that canine leptospirosis is characterized by interstitial nephritis.

Animals↗
PubMedDate not supplied

Ecological studies of enzootic Venezuelan equine encephalitis in north-central Venezuela, 1997-1998.

From 1997-1998, we investigated the possible continuous circulation of epizootic Venezuelan equine encephalitis (VEE) virus suggested by a 1983 subtype IC interepizootic mosquito isolate made in Panaquire, Miranda State, Venezuela. The study area was originally covered by lowland tropical rainforest but has been converted into cacao plantations. Sentinel hamsters, small mammal trapping, mosquito collections, and human serosurveys were used to detect active or recent virus circulation. Six strains of subtype ID VEE virus were isolated from hamsters that displayed no apparent disease. Four other arboviruses belonging to group A (Togaviridae: Alphavirus), two Bunyamwera group (Bunyaviridae), and three Gamboa group (Bunyaviridae) arboviruses were also isolated from hamsters, as well as 8 unidentified viruses. Venezuelan equine encephalitis-specific antibodies were detected in 5 small mammal species: Proechimys guairae, Marmosa spp., and Didelphis marsupialis. Mosquito collections comprised of 38 different species, including 8 members of the subgenus Culex (Melanoconion), did not yield any virus isolates. Sera from 195 humans, either workers in the cacao plantation or nearby residents, were all negative for VEE virus antibodies. Sequences of 1,677 nucleotides from the P62 gene of 2 virus isolates indicated that they represent a subtype ID lineage that is distinct from all others characterized previously, and are unrelated to epizootic VEE emergence.

Animals↗