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Biomedical subjects

R Keskinen

Publications and source records attributed to R Keskinen.

7 recordsLinked to original sources

The psychosocial effects of acne on adolescents.

To describe the psychosocial impact of acne on adolescents, and, in particular, to assess whether self-concept is affected by medical treatment, we evaluated 39 teenagers presenting for care to a community-based dermatologist. Prior to and following treatment, subjects completed a self-assessment questionnaire, the Piers-Harris self-concept scale, and underwent an objective assessment of acne severity. Fifty-eight percent of subjects were dissatisfied with their facial appearance and this in turn was correlated with feelings of embarrassment and social inhibition (for each, r = 0.48, P less than or equal to 0.005). Subjects' rating of acne severity, but not the dermatologist's, was correlated with dissatisfaction with facial appearance (r = 0.45, P less than or equal to 0.005). Despite these findings, the mean Piers-Harris total t-score (55.4 +/- 7.4) was within the normal range. Fourteen subjects (36%) returned for follow-up and 71% of these were judged by both the dermatologist and themselves to have improved. Following therapy, significant reductions in the adverse consequences of acne were observed with 42% of subjects reporting that their facial appearance was more acceptable to peers, 50% being less embarrassed, and 58% feeling less socially inhibited. Minimal improvement in mean Piers-Harris total t-score was observed (54.6 to 57.4, P = 0.004, paired t-test). Our data demonstrate that acne is perceived by adolescents to have important negative personal and social consequences, and that improvement in these areas may accompany medical treatment.

Acne Vulgaris↗

The relationship between growth and allometry.

The asymptotic allometric equations are derived by considering the relative growth of different physiological and anatomical quantities. The growth rate is assumed to be proportional to the value of the quantity, where the proportion coefficient depends on time. The allometric exponents are calculated for some organs of man and compared with the experimental values for primates. The exponents are generally time-dependent during the growth. The effect of the choice of the origin of time axis on the asymptotic allometric exponents is studied.

Biometry↗

Theoretical model of phase separation of erythrocytes, platelets, and plasma at branches.

Analytical expressions for the changes of the erythrocyte and platelet concentration are calculated as blood flows through a single bifurcation. The effect of the separation surface, which divides the blood into the two daughter vessels, upon the concentration changes is studied. Numerical fitting to the experimental data shows that both the erythrocyte and platelet distributions across the vessel are nonuniform. The maximum of the erythrocyte concentration is in the core, and of the platelet concentration, in the vicinity of the wall. A separation surface that is convex towards the axis of the vessel yields better fit to the experimental data than a concave one. Together with other studies, this suggests that flow-divider geometry depends on flow conditions and the vessel diameters. The results can be used for estimation of the distribution of erythrocytes and platelets in the microvasculature.

Blood Circulation↗

Theoretical analysis of regional blood flow studies.

Regional blood flow measurements were analyzed using a two-compartment model. The distribution of injected tracer between blood and tissue was assumed to be in equilibrium only at the beginning of the experiment. Equations for the determination of the partition coefficient of injected radionuclides from in vivo measurements were derived. These equations can also be used for estimation of the relative blood content of a tumor or an organ. The results were applied to experiments, where three diffusible radionuclides were injected simultaneously into patients with diagnosed tumors.

Argon↗