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Results for “Skin Physiological Phenomena”

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At least 19 recordsLinked to original sources
PubMed1979

Natural host defense mechanisms.

Severe injury, whether the result of a major accident, a large burn, or a complicated surgical operation, often results in sepsis. Under such conditions both specific and nonspecific host defense systems are affected. The individual facets of major concern are chemotaxis, phagocytosis, intracellular killing, complement depletion, and depression of humoral and cellular mediated immunity. The most profound changes occur in cell-mediated immunity. Within a few hours o injury, the number of circulating T cells becomes depleted, concomitantly thoracic duct lymphocytes are markedly reduced. This change is not only quantitative but functional. The clinical impact of these deficient host defense mechanisms lies in the fact that low virulent organisms may become a lethal threat to the injured patient. Currently, investigators are attempting to reverse thse deficiencies through the use of immunotherapy.

Adult↗
PubMed1978

Localization of CO2 sensor related to the inhibition of the bullfrog respiration.

CO2 sensitivity in the airways and the general skin surface of the bullfrog under urethane anesthesia or without anesthesia was investigated. Pressure in the buccal cavity as well as blood pressure in the sciatic artery were measured with a differential or a straingauge transducer. Air containing 2--14% CO2 was introduced into the regions as given below. (1) The nose and the body surface, both regions were separated from each other and independently exposed to CO2. (2) The larynx-lungs, the buccal cavity-lungs, the naso-buccal cavity separated from the airways at the glottis, and the internal or external nares, respectively. By analyzing the CO2 sensitivity of the respective regions mentioned above, both the nasal mucosa and the skin surface were found to be responsible for the respiratory inhibition by CO2. Sectioning both the olfactory and the trigeminal nerves abolished the CO2-induced inhibition mediated by the nasal mucosa and electrical stimulation of the proximal cut end of these nerves inhibited respiration. These findings suggested the existence of afferent reflex pathways from the nasal mucosa by these cranial nerves. Significance of this CO2-induced reflex was discussed.

Animals↗
PubMed1979

The challenge of biophysics to dynamic dermatology.

Dermatologic biophysics has much to offer both clinical and investigative dermatology. For the clinician, the radiation biophysicist can provide accurate measurements of ionizing and nonionizing outputs, including those for PUVA, and critical evaluation of radiation safety measures. In optics, there is a need for accurate measurements of skin color and examination of the skin at moderate magnification. The biophysicist, with the biomedical engineer, can improve all the physical modality instrumentation used in practice. In investigative dermatology, there is the cellular biophysics of radiation. Doppler techniques for skin circulation, spectroscopy of living cells, and many other applications are suggested for current and future studies.

Biophysical Phenomena↗
PubMed1977

Bridge method of skin-flap delay.

Necrosis, a catastrophic complication of skin-falp use, is due to inadequate capillary blood flow. Delay procedures, which are based on newer information regarding skin vasculature and delay dynamics, can augment surviving-flap length. A delay procedure that used multiple skin bridges was studied in 121 flaps in 21 pigs. The result was a considerably greater amount of length augmentation than has previously been reported. This enhanced effect is related to a combination of nearly maximal sympathectomy in a highly ischemic, surgically defined experimental flap.

Animals↗
PubMed1977

Effect of cutaneous stimulation on the development of misdirected wiping reflexes in skin-grafted Discoglossus pictus.

The frog, Discoglossus pictus, has been studied with respect to wiping reflex behavior developing after skin rotations performed at larval stages. Misdirected wiping reflexes were obtained only from belly skin-grafts placed on the animals' back; back skin-grafts on the belly failed to elicit any misdirected limb movements in this species. We found that misdirected reflexes occurred more readily in 3-week and older animals if not subjected to any previous test experience, than in younger naive frogs. Frogs that had been exposed to daily cutaneous stimulation between 2 to 4 weeks after metamorphosis showed a delayed development of misdirected responses.

Age Factors↗
PubMed1977

[Temperature dependent alterations of the surface-EMG and ECG: an investigation of the electrical transfer characteristics of the human skin (author's transl)].

The influence of local heating of the skin on the integrated EMG (registered with surface and subcutaneous electrodes), the amplitude of the ECG, the skin blood flow, the electrode impedance, the electrode-to-skin impedance, and the tissue impedance is investigated. Except for the increasing skin blood flow each of the variables exhibits a significant reduction with an increase in skin temperature. From these results the existence of two mechanisms is deduced mediating thermal influence on bioelectric signals picked up by surface electrodes: 1. An alteration of the signal source. 2. An alteration of the electric transfer characteristics of the tissue between signal source and electrode. Especially in quantitative surface electromyography the temperature dependence of the signal can be a source of error.

Electric Conductivity↗
PubMed1979

Black and white human skin differences.

This review of black and white human skin differences emphasizes the alleged importance of factors other than the obvious, i.e., skin color. Physicochemical differences and differences in susceptibility to irritants and allergens suggest a more resistant black than white skin. Differences appear to exist in the frequency of which several skin diseases occur among blacks and whites. A striking feature in this literature is the disagreement between authors. Common for much of this information is difficulty of interpretation, because of socioeconomic influences and other environmental factors.

Africa↗