Biomedical subjects
Publications and source records attributed to R Bravo.
Stimulation of fibroblasts with serum or purified growth factors leads to a dramatic induction of expression of both c-fos mRNA and protein within a few minutes, followed by activation of c-myc. This suggests that c-fos induction is a primary event and the earliest known effect on gene expression by growth factors.
Identification of the cellular proteins whose expression is regulated during the cell cycle in normal cells is essential for understanding the mechanisms involved in the control of cell proliferation. A nuclear protein called cyclin of relative molecular mass 36,000 (Mr 36K), whose synthesis correlates with the proliferative state of the cell, has been identified in several cell types of human, mouse, hamster and avian origin. The rate of cyclin synthesis is very low in quiescent cells and increases several fold after serum stimulation shortly before DNA synthesis. Immunofluorescence and autoradiography studies have shown that the nuclear staining patterns of cyclin during S phase have a sequential order of appearance and a clear correlation can be found between DNA synthesis and cyclin positive nuclei. The proliferating cell nuclear antigen (PCNA) and cyclin have many common properties and it has been shown that these two are identical. Recently a protein which is required by DNA polymerase-delta for its catalytic activity with templates having low primer/template ratios has been isolated from calf thymus. We report here that cyclin and the auxiliary protein of DNA polymerase-delta are identical.
This paper offers a brief review of the application of knowledge management in the field of the health sciences. This new current, which emerged in the business sphere, is seeking to win itself a space in disciplines characterised by their intensive use of information and which had traditionally assumed many of the proposals presented as novelties by these currents. The challenges and problems that knowledge management poses in the health sciences are discussed and, focusing on explicit knowledge management, solutions that are currently being developed are described.
The influence of some nutritional and hormonal factors in the growth failure detected in children of teenage mothers belonging to medium-low socioeconomic level (SEL) was studied. They were compared with children of mothers older than twenty years of the name SEL. Only growth retarded children of teenage mothers had significant delay in bone age, compared with chronological age (14.8 +/- 4.1 vs 18.2 +/- 2.2 months respectively). Children with growth failure had significantly lower plasma Zn (85.7 +/- 13.3 vs 94.6 +/- 17.9 micrograms/dl), Cu (106.2 +/- 32.5 vs 122.0 +/- 13.8 micrograms/dl) and hemoglobin (Hb) (11.7 +/- 2.1 vs 12.8 +/- 2.1 micrograms/dl) levels. No differences in plasmatic levels of thyrotropin, thyroid hormones and response of growth hormone to L-Dopa stimulation were detected in comparison with those of children with normal stature. We concluded that etiological factors of growth failure were similar in children of teenage and adult mothers according to the parameters analyzed. The increased prevalence of growth failure in children of teenage mothers may be due to a greater impact of the analyzed factors.
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