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Biomedical subjects

J Villarreal

Publications and source records attributed to J Villarreal.

At least 19 recordsLinked to original sources
PubMed2000

Tumor necrosis factor receptor II (TNFRII) exon 6 polymorphism in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that exhibits extensive clinical heterogeneity. Several studies have suggested a role for tumor necrosis factor alpha (TNFalpha) in SLE and recently, the locus encompassing the TNF receptor II (TNFRII), which is a mediator of TNF effect, was amongst the candidate loci suggested by genetic linkage studies of multi-case SLE families. Komata et al. reported an association between a polymorphism at position 196 (R allele) of TNFR II and SLE in Japanese patients. We have typed SLE patients from two different ethnic populations, Spanish and UK Caucasoids, for this polymorphism using a polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP)-based technique. No significant differences in allele or genotype frequencies were found between cases and matched controls in either population. The TNFRII 196R allele does not appear to be associated with SLE susceptibility in either Spanish or UK populations.

Alleles↗
PubMed2000

Anticardiolipin antibodies in patients with chronic hepatitis C virus infection: characterization in relation to antiphospholipid syndrome.

The antiphospholipid syndrome (APS) is usually defined by the association of clinical manifestations that comprise venous and/or arterial thrombosis, recurrent fetal losses, and thrombocytopenia, along with the presence of anticardiolipin (aCL) antibodies and/or lupus anticoagulant. Various infectious diseases can induce aCL; however, these antibodies are not usually associated with thrombotic events, as happens with autoimmune diseases, in which these antibodies need the presence of beta(2)-glycoprotein I. Levels of immunoglobulin G (IgG) and IgM aCL antibodies were determined by enzyme-linked immunosorbent assay for 243 patients with chronic hepatitis C virus (HCV) infection and 100 healthy controls. Clinical events of APS, the level of beta(2)-glycoprotein dependence of aCL, the presence of cryoglobulins and other autoantibodies, and cross-reactivity between purified aCL and HCV were evaluated. Positive results for aCL antibodies were found more frequently (3. 3%) for the patients with HCV infection than for healthy controls (0%). All positive aCL antibodies were beta(2)-glycoprotein I independent. No significant association was found between aCL antibodies and clinical manifestations of APS, neither was one found between the presence of other autoantibodies or cryoglobulins and that of aCL. Finally, no cross-reactivity between aCL antibodies and HCV antigens was observed. As previously reported, aCL antibodies seem to be an epiphenomenon, and they do not have clinical or laboratory significance in HCV patients.

Adolescent↗
PubMed1998

Yeast ribosomal protein L26 is located at the ribosomal subunit interface as determined by chemical cross-linking.

Previous studies suggested that yeast ribosomal protein L26 was a candidate for the ribosomal subunit interface region. The present study used protein-protein cross-linking to identify neighboring proteins in intact 80S ribosomes of Saccharomyces cerevisiae. To facilitate identification of cross-linked pairs involving L26, 80S ribosomes were first treated with 5-iodoacetamidofluorescein to selectively label L26. Protein cross-links were produced with dithiobis[succinimidyl] propionate or N-succinimidyl-3-[2-pyridyldithio] propionate and analyzed by electrophoresis on two-dimensional diagonal polyacrylamide gels containing SDS. L26 was detected under UV and its cross-linked partner, detectable after staining with Coomassie blue, was located below the diagonal and was coincident with L26 on a single vertical axis. The identity of the partner was determined by its co-migration with 60S and 40S ribosomal protein markers on two-dimensional gels. Two protein pairs involving L26 and 40S subunit proteins were identified. The finding provided experimental evidence to support that L26 is located at the ribosomal subunit interface. A model that incorporates the present findings and the published data on intra-subunit protein pairs is proposed for the yeast 80S ribosome.

Cross-Linking Reagents↗
PubMed1993

Bioimpedance monitoring of rehydration in cholera.

Measurement of bioimpedance (BI) is a simple non-invasive technique that relies on the different conductivity of tissues to define body composition and can be easily adapted to automated monitoring. We assessed the accuracy of BI in monitoring rehydration and acute fluid fluxes in 35 Peruvian cholera patients. Patients were monitored throughout the acute phase of diarrhoea and followed up at 3 and 10 days. BI was compared with other objective measures of dehydration including packed cell volume, serum protein, and calculated fluid balance. BI rapidly detected inadequate treatment and acute fluid flux, correlating highly with intravascular hydration as measured by serum protein and packed cell volume. BI values during dehydration were significantly raised compared with 10-day convalescent values and age-matched controls (p < 0.05). We also encountered an unexpected difference in the bioelectrical response to dehydration and rehydration between sexes. We conclude that BI has uses in monitoring dehydrated patients, in oral rehydration trials, and in physiological studies.

Acute Disease↗
PubMed1990

[Treatment of diarrheic disease at home. Comparison of 2 forms of oral solutions: liquid and concentrated in small bags].

One hundred children, ranging in ages from a month to a year, with acute diarrhea who were treated at home following the basic standard recommendations, were studied. In order to prevent dehydration, half of the children were given oral solution (OS) containing the concentrated official formula in packets (group A), and the remaining half was given a commercially prepared ready-to-use OS (group B). During the treatment period, two house calls were made and the third day the patient was asked to come in for a check-up at the hospital. The clinical and socioeconomic characteristics were similar in both groups. The majority of parents made some reference to the "salty" taste of their OS, while only a few thought it has a sweet taste. In Group B, there were greater numbers of relatives who did not wash their hands before administering the OS and did it through bottles. A reminder was given on suggestive signs of dehydration expected, during the second home visit, although they were few. In both groups the average amount of OS administered was greater than 40 mL/kg/24 hours. The majority of the patients gained weight during the treatment. Four patients showed signs of slight dehydration (three from group A and one from group B). The OS's bacteriologic examination was positive for enteropathogens in 16% of the samples from group A and in 5% from group B. The average time the diarrhea continued was similar for both groups. Sodium concentration ranged from 60 to 120, potassium from 15 to 30 mmol/L, in 85% of those cases in group A and 98% in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1981

Isolation and sequence analysis of a somatostatin-like polypeptide from ovine hypothalamus.

A large somatostatin-like polypeptide of apparent molecular weight 3000-4500 [4K somatostatin (SS)] was isolated from ovine hypothalamus. The polypeptide was obtained in the methionine sulfoxide form. Two microsequence analyses of 0.6 and 1.8 nmol of 4K SS were performed with a modified 890 C spinning cup sequencer. The sequencing data together with results of amino acid analysis and C-terminal end-group determination indicated that 4K SS was identical with somatostatin-28 (SS-28) isolated from procine upper small intestine and sequenced by Pradayrol et al. [Pradayrol, L., Jörnvall, H., Mutt, V., & Ribet, A. (1980) FEBS Lett. 109, 55-58]. No free cysteine sulfhydryl group could be detected, so that it was assumed that the two cysteine residues of ovine SS-28 formed an intramolecular disulfide bond. Besides the structure of SS-28, the N-terminal first 30 residues of an unknown polypeptide from ovine hypothalamus were sequenced as follows: H-Ile-Pro-Ile-Tyr-Glu-Lys-Lys-Tyr-Gly-Gln-Val-Pro-Met-Cys-Asp-Ala-Gly-Glu-Gln- Cys-Ala-Val-Arg-Lys-Gly-Ala-Arg-Ile-Gly-Lys. Trypsin cleaved the somatostatin (SS) entity less selectively from ovine hypothalamic SS-28 than from rat hypothalamic 12 000-dalton SS-like polypeptide (12K SS). Native ovine hypothalamic SS-28 was found to be highly potent in inhibit growth hormone release from cultured rat anterior pituitary cells. The results raised doubts that ovine SS-28 would be an SS precursor and indicated that SS-28 itself may possess regulatory functions.

Amino Acid Sequence↗
PubMed1980

Advances in gastric emptying studies by means of computerized scintigraphy.

Gastric emptying studies were begun in 1833. However, as information on this phenomenon became more available it became more difficult to unify studies in order to make them more applicable for the study and treatment of functional disturbances and organic diseases. In this work an innocuous, objective and precise method is described, that consists of the study of gastric emptying in two stages in healthy individuals. In the first, basic substances of food were administered and in the second, usual 1,050 calorie meals all marked with Technetium-99 m macroaggregates, were given. Two scintillation cameras were used coupled to computerized data processing systems from where quantitative information and black and white Polaroid pictures were obtained. In the first stage, six healthy volunteers were studied who received basic food substances in different sessions. In the second stage, 10 healthy volunteers were studied who received a type of meal common in our environment. In all cases gastric emptying curves were obtained plotting radioactivity counts v.s. time. Weibull's distribution was the statistical method applied. According to the ingested substances, results showed different emptying curves of a complex exponential type. Although gastric emptying is immediate, it is parallel to the presence of plateaus in the initial part of the study; an apparently delayed phenomenon that had been overlooked and is explained in the discussion part of this paper. Results obtained have offered the possibility of an abundant volume of studies that should clarify existing doubts in the future with a wide field for clinical application.

Adolescent↗