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Biomedical subjects

J L Gonzalez

Publications and source records attributed to J L Gonzalez.

13 recordsLinked to original sources
PubMed1992

Placebo-controlled efficacy study of hepatitis A vaccine in Valdivia, Chile.

A placebo-controlled, double-blind study on the efficacy of a hepatitis A vaccine (SmithKline Beecham Biologicals) was started in a region of Chile in September 1990, using hepatitis B vaccine as control. A total of 260 healthy children, 6-15 years of age, negative for antibody to hepatitis A virus (anti-HAV), antibody to HAV immunoglobulin M (IgM), hepatitis B surface antigen, and antibody to hepatitis B surface and core antigens by ELISA tests within 7 days before vaccination, were randomly assigned to two study groups: 128 children received the vaccine with a yellow label (group 1), and 132 children the vaccine with an orange label (group 2) at months 0, 1 and 6. Blood for serology and transaminase determination was drawn at months 1, 2, 6, 7 and 12. Both vaccines were tolerated equally well and no serious side effects were seen. In group 1 (presumed hepatitis A vaccine group), anti-HAV was detected (20% inhibition was used as the cut-off level) in 122 of 128 children (95.5%) tested at month 1, in 126 of 127 (99.2%) at month 2, in 126 of 127 (99.2%) at month 6 and in 126 of 126 (100%) at month 7. One anti-HAV seroconversion seen at month 1 was associated with presence of anti-HAV IgM and therefore probably represents HAV infection. Geometric mean anti-HAV concentration of the other children was 128, 342, 214 and 2301 mIU/ml at months 1, 2, 6 and 7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Training of conversational skills with institutionalized elderly: a preliminary study.

16 residents in a Residential Care Home for elderly people volunteered and were trained in a social skills program aimed at increasing conversational skills. Subjects were assigned randomly to three groups, one experimental and two control groups (placebo and waiting list). The techniques used in the experimental group were behavior rehearsal, feedback, modeling, discriminative reinforcement, verbal instructions, and homework. Relative to control groups, experimental subjects showed significant increases in conversational skills, such as receiving information, speaking-up, and giving information. They also showed a significant decrease in their scores on Zung's Self-rating Scale of Depression compared with the two control groups. They showed an increase in assertive responses and a decrease in aggressive and inhibited responses. These changes remained when follow-up was made 3 mo. later, suggesting the potential utility of this training program with elderly persons residing in old people's homes.

Aged↗
PubMed1985

Decrease of choline acetyltransferase activity of rat cortex capillaries with aging.

Choline acetyltransferase (ChAT) activity was estimated in brain cortex capillaries isolated from 3-, 12-, 18-, and 24-month-old rats. Maximum enzymatic activity was found at 12 months (55 +/- 0.3 pmol X mg-1 protein X min-1; mean +/- SEM) and then it decreased to reach a minimum at 24 months (34 +/- 3.1 pmol X mg-1 protein X min-1). A less marked decrease of enzymatic activity was also found in cortex homogenate and in a synaptosomal fraction obtained from the same groups of rats. Loss of ChAT of brain capillaries with aging could be related to a general phenomenon of cortical cholinergic deficit in that condition.

Aging↗
PubMed1983

Testicular amyloidosis in hamsters experimentally infected with Leishmania donovani.

Thirty hamsters were inoculated intraperitoneally with Leishmania donovani. Testes were examined grossly and histologically by light and electron microscopy. Progressive testicular atrophy developed. Spermatogenic cells of the seminiferous tubules showed vacuolar degeneration and decreased in number leading to a total azoospermia in the final weeks of the pathological process. Lymphoplasmocytic infiltrates with macrophages containing leishmanias appeared in the intertubular space. Amyloid deposits in the intertubular space and tubular basement membrane were identified by optical and ultrastructural methods. It has been suggested that testicular amyloidosis may have a pathogenic mechanism related to a dysfunction of plasma cells and stimulation of the reticuloendothial system, due to the antigenic character of the parasite.

Amyloidosis↗
PubMed1981

Discrepancy in the regulatory effects of sodium and guanine nucleotides on adrenaline and clonidine binding to alpha 2-adrenoceptors in human fat cell membranes.

Guanine nucleotides and sodium were found to reduce the affinity of adrenaline for the alpha 2-adrenoceptor sites labelled by [3H]yohimbine in human fat cell membranes. Surprisingly, the negative regulation by these agents was far weaker when clonidine, the alpha 2-agonist prototype was used. The results are discussed in relation to the weaker or the lack of adenylate cyclase inhibition promoted by clonidine and indicate that the formation of the lower affinity state of the alpha-receptor is essential to the alpha 2-adrenoceptor-mediated adenylate cyclase inhibition.

Adipose Tissue↗
PubMed1980

Effect of amphetamine and dopamine on oxygen uptake of rat brain slices in vitro.

Effects of d-amphetamine and dopamine on rat brain cortical slices respiration were estimated to assess whether these drugs might modify membrane (Na+ + K+)-ATPase activity in intact cells as they do in isolate enzyme systems. d-Amphetamine, 10(-5) M (140%), 10(-6) M (123%) 10(-7) M (131%) and 10(-7) M (129%). These results may be related to estimates of (Na+ + K+)-ATPase activity in subcellular systems. In an incubation medium containing calcium, 10(-4) M ouabain does not modify brain slices respiration, but fully antagonizes oxygen consumption increases induced by d-amphetamine or dopamine, which might thus be mediated by membrane ATPase activity. Either phenoxybenzamine, oxprenolol or halo-peridol, nullify those metabolic effects of d-amphetamine and dopamine, by means of unspecific mechanisms rather than by a specific interaction at drug receptor sites. It is suggested that cell respiratory control is the final resultant of mechanisms which might be separately, and oppositely, modified by drugs.

Amphetamine↗
PubMedDate not supplied

A survey of cognitive functioning at difference glucose levels in diabetic persons.

Cognitive functioning was assessed in diabetic patients during hypoglycemia (60 mg/dl), euglycemia/control (110 mg/dl), and hyperglycemia (300 mg/dl). Blood glucose levels were set and maintained to within 4% of targeted levels by an artificial insulin/glucose infusion system (Biostator). Attention and fine motor skills, assessed by visual reaction time, was slowed at altered glucose levels. Performance was less impaired during hyperglycemia than hypoglycemia when a longer interstimulus interval was used, although it was still slower than normal. The time required to solve simple addition problems was increased during hypoglycemia, although reading comprehension was not affected. The possibility that some automatic brain skills are disrupted at altered glucose concentrations is discussed, while associative or inferential skills may be less affected.

Attention↗