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Biomedical subjects

J Last

Publications and source records attributed to J Last.

4 recordsLinked to original sources
PubMed1985

Changes in response to ascorbic acid administered orally to rat pups: lung collagen, elastin and protein synthesis.

Rat pups were supplemented orally with high doses of L-ascorbic acid (AA) or D-isoascorbic acid (IA) throughout suckling. The regulation of AA in the lung and its relationship to collagen and elastin deposition were examined. Based on known responses of smooth muscle cells and fibroblasts in culture to high concentrations of AA, it was hypothesized that a markedly elevated intake of AA should increase net collagen deposition, but decrease net elastin deposition in the neonatal rat lung. In two experiments, groups of rat pups were gavaged daily with AA (in saline), in amounts corresponding to 0.1, 1 or 2% of the total consumed milk solids. As controls, pups were gavaged with IA (2% of the milk solids) or saline. The treatments were initiated 2 d postpartum and continued for 19 or 23 d. Compared to the saline-gavaged pups. AA and IA were elevated (twofold) in serum and lung at d 11, but not at d 25. Urinary excretion represented a major route for elimination of excess AA and IA. With respect to collagen and elastin accumulation, only elastin consistently was altered (10-20% decrease) in groups supplemented with AA or IA at the termination of experiments. The rodent appears to defend against elevation of AA concentration in the lung. Consequently, the putative effects of AA on the net deposition of lung collagen and elastin in vivo are less obvious than effects reported by others from in vitro studies.

Administration, Oral↗
PubMedDate not supplied

Implications for human health of global ecological changes.

Comparatively little attention has been given to the health implications of global ecological changes on human health, with the exception of concern over ozone depletion leading to an increased frequency of ultraviolet irradiation-induced skin cancer and cataracts. The implications for human health of five large-scale ecological disruptions were explored: climate change (greenhouse effect), ozone depletion, acid precipitation, transregional pollution, and demographic changes. Limitations of presently available data and the uncertainty of current interpretations of apparent trend is emphasized. Rigorous assessment of the effects of these changes and the response required from public health professionals is needed. This overview provides a point of departure.

Acid Rain↗