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Biomedical subjects

K M Dixon

Publications and source records attributed to K M Dixon.

7 recordsLinked to original sources
PubMed2004

1,25-Dihydroxyvitamin D and three low-calcemic analogs decrease UV-induced DNA damage via the rapid response pathway.

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] is anti-apoptotic in human keratinocytes, melanocytes and fibroblasts after ultraviolet (UV)-exposure. To date, there is no published data on the effects of 1,25(OH)(2)D(3) or its analogs on DNA damage in irradiated skin cells. In these skin cells, 24h pre-treatment with 1,25(OH)(2)D(3) dose-dependently (10(-12) to 10(-8)M) decreased CPD damage by up to 60%. This photoprotective effect was also seen if the 1,25(OH)(2)D(3) was added immediately after irradiation and was mimicked by QW-1624F2-2 (QW), a low-calcemic 1beta-hydroxymethyl-3-epi-16-ene-24,24-difluoro-26,27-bis homo hybrid analog. The well-studied low calcemic, rapid acting agonist analogs 1alpha,25(OH)(2)lumisterol(3) (JN) and 1alpha,25(OH)(2)-7-dehydrocholesterol (JM) also protected skin cells from UV-induced cell loss and CPD damage to an extent comparable with that of 1,25(OH)(2)D(3). In contrast, the rapid response antagonist analog 1beta,25(OH)(2)D(3) (HL) completely abolished the photoprotective effects (reduced cell loss and reduced CPD damage) produced by treatment with 1,25(OH)(2)D(3), JN, JM and QW. Evidence for involvement of the nitric oxide pathway in the protection from CPD damage by 1,25(OH)(2)D(3) was obtained. These data provide further evidence for a role of the vitamin D pathway in the intrinsic skin defenses against UV damage. The data also support the hypothesis that the photoprotective effects of 1,25(OH)(2)D(3) are mediated via the rapid response pathway(s).

Apoptosis↗
PubMed1994

Oppressive limits: Callahan's foundation myth.

Daniel Callahan has not simply proposed alterations of important features of the health economy. He has constructed a blue print for society drawing on concepts of what is natural and appropriate to human beings. He is, in effect, establishing a new social order. Like any social order, Callahan's system has its justificatory schemes or founding myths. This paper offers a feminist examination of the functions that these four myths-the concept of a whole of life; the stages of life; a tolerable death; and a reconstruction of the meaning of the aged in terms of sacrifice-fulfill in Callahan's new social order. Callahan's concept of a whole of life reflects the power he assigns to nature, and the futility and harm he associates with attempts to repudiate biological imperatives. It introduces the stages of human life, tolerable death, and aging. The paper critically examines these concepts.

Aged↗
PubMed1993

The role of the hospital in the evolution of elite cultures of medicine.

Rosenberg argues that a culture of medicine articulates a unique medical vision reflecting scientific ideologies and perceptions, professional values and rewards, career patterns, and the work context of each generation of physicians (Rosenberg, 1987, p. 7). It might be more accurate, however, to recognize multiple cultures of medicine. This paper traces American hospitals' contributions to three specific aspects of certain elite cultures of medicine. Its first section introduces and explores these aspects transhistorically. They are: a stratified paradigm of the physician-patient relationship, the equation of competence with specialization, and a pattern within a stratified model of medicine called the "Lone Ranger syndrome." A brief historical profile subsequently highlights changes in the structure and function of American hospitals in the 19th century. The three remaining sections chart the ebb and flow of the prominence and power of these specific aspects of elite cultures of medicine across three historical periods: the late 19th century, 1910-1930, and the post World War II era.

History, 19th Century↗