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Biomedical subjects

E Tur

Publications and source records attributed to E Tur.

50 records · Page 3Linked to original sources
PubMed1985

Are there age and racial differences to methyl nicotinate-induced vasodilatation in human skin?

Preliminary experiments have been performed to determine whether there are age and racial differences in the response of human skin to the topically applied vasodilator methyl nicotinate. With the use of a constant stimulus (a 15-second exposure to a 100 mM aqueous solution of drug), the subsequent time-course of the vasodilatation response was followed noninvasively and objectively with the optical technics of laser Doppler velocimetry (LDV) and photoplethysmography (PPG). Three groups of subjects were considered: young white subjects (20 to 30 years of age), elderly white subjects (63 to 80 years old), and young black subjects (20 to 30 years old). Analysis of the results shows that the time to peak response, the area under the response-time curve, and the time for the response to decay to 75% of its maximum value are statistically indistinguishable for all three groups at the p = 0.05 level of significance. Only the magnitude of the peak response revealed some significant differences between the cohorts (young greater than black, determined by PPG; young greater than old, determined by LDV). The data suggest, therefore, a remarkable similarity in response across a wide range of skin types. The origin of this consistency may, however, be complex and is not revealed by these experiments.

Adult↗
PubMed1985

Spatial variability of vasodilatation in human forearm skin.

Vasodilatation elicited by topical application of methyl nicotinate was measured by photoplethysmography at various positions on human ventral forearm skin. The time-to-peak response, the magnitude of the peak response, the area under the response-time curve and the time for the response to decay to 75% of the maximum value, were recorded at six positions on the left and right forearms of eight subjects. There was no significant difference between response on the right and left forearm sites and no difference in response between the lateral and medial sites on the forearms. In a second experiment, the vasodilatation was measured at proximal and distal positions on the forearm. The magnitude of the peak response at the proximal position was significantly higher than that found distally (P less than 0.01) as was the area under the response-time curve (P less than 0.05). These results suggest a possible cause for the variation observed in vasoconstrictor assays of corticosteroids.

Adult↗
PubMed1983

Noninvasive assessments of the percutaneous absorption of methyl nicotinate in humans.

Percutaneous penetration of the vasodilator methyl nicotinate (methyl 3-pyridinecarboxylate) has been monitored in vivo in humans with the noninvasive techniques of laser Doppler velocimetry and photopulse plethysmography. These optical methods use different technologies to generate a voltage output which is related to perfusion of the cutaneous microcirculation. The procedures are therefore sensitive to the pharmacologic stimulus and duration of local vasodilation. Following topical application of methyl nicotinate, excellent correlation was found between the response of both methods and the visual observation of erythema. Lower drug concentrations delayed the onset and magnitude of the response and shortened the time period for which elevated microperfusion was observed. These techniques appear to provide a useful noninvasive assessment of the time course of drug behavior in the region of skin to which topical application is made.

Erythema↗
PubMed1983

Basal perfusion of the cutaneous microcirculation: measurements as a function of anatomic position.

Noninvasive optical techniques of photopulse plethysmography (PPG) and laser Doppler velocimetry (LDV) have been used to identify regional variations in the basal skin blood flow of humans. The procedures assess either the volume (PPG) or the volume-velocity product (LDV) of cutaneous blood vessel perfusion. Fifty-two anatomic positions have been studied in 10 normal subjects resting horizontally. The mean perfusion levels were ranked to reveal the variations in cutaneous blood flow as a function of body site. Groups of data were collected into cohorts and average perfusion values for the subjects within each cohort were compared by the Newman-Keuls multiple comparison test. Most transparently, the results reveal a collection of regions (fingers, palms, face, ears) for which cutaneous perfusion is much higher than all other positions. More subtle differences and some unexpected similarities, however, are also apparent and, in some cases, agree or, in others, conflict, with previously published information. With some exceptions, good general agreement between the two techniques was observed.

Adult↗
PubMed1983

Noninvasive assessment of local nicotinate pharmacodynamics by photoplethysmography.

The local pharmacodynamics of a topical vasodilator (methyl nicotinate) has been followed noninvasively using photopulse plethysmography. This technique is sensitive to changes in blood flow through the cutaneous microcirculation and responds to the pharmacologic stimulus of the vasoactive agent employed. Five different application sites for the drug were studied and the time course of the local effect (i.e., onset, duration, and decay) was recorded. The applied amount of drug elicited, within a short period, a response which was saturable such that the observed increase in blood flow reached a plateau level. The decay of the elevated perfusion required approximately 1 h, suggesting a half-life for elimination of the drug from the skin of about 10 min. This result agrees closely with other reported values and suggests that the pharmacodynamic measurements of this study may prove useful in elucidating aspects of dermal pharmacokinetics.

Administration, Topical↗
PubMed1983

Alkaline phosphatase immuno-enzymatic technique in the diagnosis of pemphigus vulgaris.

Alkaline phosphatase was used in an immuno-enzymatic procedure to detect tissue-bound and circulating antibodies in pemphigus vulgaris. Pemphigus antibodies were revealed by a direct method using alkaline phosphatase conjugated goat anti-human IgG. Cryostat sections were incubated with the specific antiserum, and alkaline phosphatase activity was then revealed histochemically either by Gomori's technique or by the azo dye method. The sections were examined by light microscopy and intercellular staining was demonstrated in the epidermis. The indirect method, in which the patient's serum was incubated with sections of normal skin, gave similar results. Using parallel sections, an immunofluorescent technique was used to demonstrate tissue-bound and circulating antibodies. The alkaline phosphatase method appeared to be slightly less sensitive than the immunofluorescent method.

Alkaline Phosphatase↗