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Biomedical subjects

G E Folk

Publications and source records attributed to G E Folk.

At least 19 recordsLinked to original sources

The evolution of sweat glands.

Mammals have two kinds of sweat glands, apocrine and eccrine, which provide for thermal cooling. In this paper we describe the distribution and characteristics of these glands in selected mammals, especially primates, and reject the suggested development of the eccrine gland from the apocrine gland during the Tertiary geological period. The evidence strongly suggests that the two glands, depending on the presence or absence of fur, have equal and similar functions among mammals; apocrine glands are not primitive. However, there is a unique and remarkable thermal eccrine system in humans; we suggest that this system evolved in concert with bipedalism and a smooth hairless skin.

Animals↗

B16 melanoma in hairless mice: a model for thermographic research.

Little is understood concerning the mechanism of tumor-induced thermographic abnormalities observed in man. An ideal animal model is lacking. In an effort to create such a model we have worked with hairless mice, subcutaneously inoculated with B16 melanoma cells. This report documents the progress of that work and the subsequent development of a totally satisfactory system for the study of such tumors in a hairless animal.

Animals↗

Temperature over tumors in hairless mice.

The question of whether tumors are warmer or colder than surrounding tissue is considered in these experiments which use a highly suitable animal model, the hairless mouse. Temperatures of skin over induced growing subdermal tumors in these mice were monitored by AGA 680 Color Thermovision. The skin over the tumors does not cool over time but on the contrary becomes warmer. This is probably due to an increase in vascularization rather than increased metabolic rate.

Animals↗

Importance of circadian rhythms in animal cell cultures.

Circadian rhythms are a characteristic feature of many cell and organ cultures. Such rhythms may be important in the interpretation of data from cells in culture. More examples of circadian rhythms in tissue culture are badly needed to understand this phenomena. However, they will only be expressed under optimum and well-understood conditions.

Animals↗

The role of adrenoceptors in norepinephrine-stimulated VO2 in muscle.

The purpose of this study was to characterize the norepinephrine (NE)-evoked calorigenic response of an isolated perfused rat muscle preparation into alpha-and/or beta-adrenergic components. Epinephrine was as effective as NE in evoking the increase in oxygen consumption. The alpha-agonist, phenylephrine, was also as effective as NE in eliciting an increase in oxygen consumption by the muscle. Isoproterenol (beta-agonist) had no effect on the VO2 of the preparation. Phentolamine, an alpha-blocker, completely blocked the NE-stimulated VO2. Propranolol (beta-antagonist) could also completely block the NE induced VO2 but this drug was found to be less potent. It was concluded that the NE-induced calorigenic response of muscle cannot be classified either strictly as an alpha-or beta-response, but unlike brown adipose tissue, the alpha-response seems to predominate in skeletal muscle. Also, it appears as though different mechanisms of action may be involved in the NE-stimulated VO2 in skeletal muscle and brown fat.

Adrenergic alpha-Agonists↗