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A J Baker

Publications and source records attributed to A J Baker.

116 records · Page 7Linked to original sources
PubMed1985

Diminished internalization and action of 1,25-dihydroxyvitamin D3 in dermal fibroblasts cultured from New World primates.

We investigated the occurrence of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-resistant osteomalacia in the New World primate colony of Saguinus imperator at the Los Angeles Zoo. The mean serum concentration of 1,25-(OH)2D3 was elevated 5-fold in the New World primates compared to that in their Old World counterparts. The specific internalization of 0.6 nM [3H]1,25-(OH)2D3 by cultured dermal fibroblasts from New World primates was reduced 75% compared to that by cells from Old World primates or man. The decrease in hormone uptake resulted from a decrease in the number of high affinity intracellular binding sites for 1,25-(OH)2D3 and apparently caused a 90-95% reduction in 1,25-(OH)2D3-induced 25-hydroxyvitamin-D3-24-hydroxylase activity. There was no alteration in the capacity or avidity of New World primate serum for 1,25-(OH)2D3 compared to that of serum from Old World primates. These data suggest that the occurrence of vitamin D-resistant osteomalacia in New World primates is the result of decreased high affinity, receptor-mediated uptake of 1,25-(OH)2D3 by the target cell.

Animals↗
PubMedDate not supplied

Trypanosoma cruzi infection in Leontopithecus rosalia at the Reserva Biológica de Poco das Antas, Rio de Janeiro, Brazil.

Wild golden lion tamarins (Leontopithecus rosalia) - endangered primates that are native to the Brazilian Atlantic coastal forest - were surveyed for the presence of Trypanosoma cruzi with the use of Giemsa-stained blood smears, hemocultures and an indirect immunofluorescence assay (IFAT). Positive IFAT with titers ranging from 1:20 to 1:1280 were observed in 52% of the 118 wild tamarins examined and the parasite was isolated from 38 tamarins. No patent parasitemia was observed among the tamarins from which T. cruzi was isolated. Serum conversion and positive hemoculture was observed for three animals that had yielded negative results some months earlier, which indicates that T. cruzi is actively transmitted among tamarins. In contrast to observations with other sylvatic isolates, those from the tamarins were significantly more virulent and most of them produced mortality in experimentally infected Swiss mice. Some variation in the kDNA restriction profiles among the isolates was observed. Electrophoresis with GPI, G6PDH, IDH, MDH and ME enzymes showed a Z2 profile.

Animals↗
PubMedDate not supplied

The Home Instruction Program for Preschool Youngsters (HIPPY).

The Home Instruction Program for Preschool Youngsters (HIPPY) is a two-year home-based early education intervention program designed to help parents with limited formal education prepare their four- and five-year-old children for school. This article begins with a brief overview of the HIPPY program and then presents the findings from a series of interconnected research studies, including a two-site, two-cohort evaluation in New York and Arkansas, a one-site case study, and a three-site qualitative study. With respect to program effectiveness, results varied across the New York and Arkansas sites and across participating cohorts at each site. For Cohort I, children who had been enrolled in HIPPY scored higher than children in the control/comparison groups on measures of cognitive skills (New York), classroom adaptation (New York and Arkansas), and standardized reading (New York); and more children were promoted to first grade (Arkansas). For Cohort II, comparison group children outperformed HIPPY children on school readiness and standardized achievement at posttest (Arkansas). Analyses to account for the differing results between cohorts were inconclusive. Qualitative analyses revealed considerable variation in parent involvement in HIPPY. Program staff identified four patterns of attrition from HIPPY: (1) early attrition within the first month after enrollment, (2) attrition between the program's first and second years, (3) attrition due to changes in the life circumstances of participating families, and (4) attrition due to turnover among the home visitors. Families were more likely to participate in in-home than out-of-home aspects of the program (for example, group meetings), but different family characteristics were associated with participation in the in- and out-of-home aspects of the program. The authors conclude with recommendations for future practice and research.

Child, Preschool↗