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Biomedical subjects

S Vargas

Publications and source records attributed to S Vargas.

At least 37 records · Page 2Linked to original sources
PubMed1985

Low endemicity and low pathogenicity of rotaviruses among rural children in Costa Rica.

Rotaviruses were prospectively studied in 51 rural Costa Rican children from birth to two years. Samples of feces were collected weekly over a 33-month period. Rotavirus was detected in 45 (1.04%) of 4,317 fecal specimens; 39 infections were documented (an incidence of 0.5 infection per child-year), only five of which were associated with diarrhea (a pathogenicity of 12.8%). Secretory antibody in fecal extracts, detected in six of 39 infections, was short lived and did not protect against reinfection. Serum antibody was present in 69.6% of two-year-old children, but was not detected in 18.8% with documented infections. On the other hand, serum antibody was present in six of 14 children in whom rotavirus was not detected, thus increasing the overall incidence to 0.6 infection per child-year. The combination of prolonged breast-feeding, exposure to a lower infecting dose (compared with urban children), and a higher standard of hygiene than expected may explain the low incidence and low pathogenicity of rotavirus among these rural children.

Age Factors↗
PubMedDate not supplied

A meta-analysis of research on sensory integration treatment.

OBJECTIVE: The purpose of this study was to find whether existing studies of treatment using sensory integration approaches support the efficacy of these approaches. METHOD: With meta-analysis, the results of sensory integration efficacy research studies published from 1972 to the present were synthesized and analyzed. Sixteen studies were used to compare sensory integration effect with no treatment (SI/NT), and 16 were used to compare sensory integration effect with alternative treatments (SI/ALT). Overall average effect sizes, comparisons of the effect sizes for different dependent variables, and secondary factors associated with effect size variation were examined. RESULTS: The weighted average effect size of SI/NT studies was .29. However, there was a significant difference between the average effect sizes of the earlier studies (.60) and the more recent studies (.03). Of the outcome measures, larger effect sizes were found in the psychoeducational category (.39) and motor category (.40). Of SI/ALT studies, the average effect size was .09, not significantly different from zero. CONCLUSION: Three central conclusions can be made. First, in the SI/NT comparison, a significant effect was replicated for sensory integration treatment effects in earlier studies, but more recent studies did not show overall positive effects. Second, larger effect sizes were found in psychoeducational and motor categories. Third, sensory integration treatment methods were found to be as effective as various alternative treatment methods.

Child↗
PubMedDate not supplied

[Image characterization of Alzheimer's disease associated with the E280A-PS1 mutation. Case-control study: MRI findings].

INTRODUCTION AND METHODS: In order to compare the magnetic resonance image characteristics of individuals belonging to pedigrees carrying the mutation E280A-PS1 associated to early onset Alzheimer disease, coming from Antioquia, Colombia, 78 individuals were studied. 47 of them were carriers of the mutation, 23 of those presented symptoms and 31 individuals being controls (non carriers of the mutation). RESULTS: In summary, significative differences were appreciated between symptomatic individuals and those asymptomatic. There was not significant difference between asymptomatic carriers and the controls. The presence of the perihippocampal fissure constituted a difference statistically significant between the symptomatic individuals and those carriers asymptomatic and between the symptomatic ones and the controls. The interuncal distance increased significantly was another difference between symptomatic and asymptomatic individuals and among symptomatic and control group. The lobar atrophy and the ventriculomegaly were found in symptomatic individuals and they correlate with the disorder graveness. There was not significance in the presence of infarcts and/or hippocampal hyperintensities. CONCLUSION: These results corroborate the statement that magnetic resonance image is very useful in the diagnosis and follow-up of individuals affected by early onset Alzheimer disease.

Age of Onset↗
PubMedDate not supplied

[Diagnostic use of ELISA, IgG, IgM, IgA and ELISA IgG avidity in recent and chronic toxoplasmosis].

Toxoplasmosis, a world-wide zoonotic infection, is generally asymptomatic and benign in immunocompetent individuals, but it can be serious in immunodeficiencies particularly in patients with acquired immunodeficiency syndrome and in children infected in utero. So, it is important to dispose methods which permit discriminate between recent and chronic infections. In order to contribute to improve the diagnosis of toxoplasmosis ELISA IgG, IgM, IgA and ELISA IgG avidity were performed in 15 and 24 sera from patients suspected of having acute and chronic infection respectively, according dye test (DT) titres. ELISA IgG was positive in both groups, ELISA IgM was positive in 78.6 and 58.3% respectively, while ELISA IgA was positive in 85.7 and 33.3% of recent and chronic group respectively. In those sera with low IgG avidity (18.8%) we found specific IgM in 71.5 and 4.2% and IgA in 78.6 and 0.0% of recent and chronic groups respectively. Parallelling, 208 sera samples were classified according to the results of DT, indirect hemagglutination and complement fixation tests in the following groups: acute (97), intermediate (36), chronic (35) and negative (40). The results were: acute (96.9-64.9-55.6 and 65.9%); intermediate (97.2-63.8-44.4 and 47.2%); chronic (45.7-42.8-5.7 and 34.3%) for IgG, IgM, IgA and low IgG avidity respectively. The use of both acute markers, IgA and low IgG avidity in the diagnosis of toxoplasmosis is discussed.

Animals↗