The impact of 10% α-hydroxy acid emulsion on skin pH.

BACKGROUND/AIMS: The effects of a 10% α-hydroxy acid (AHA) oil/water (O/W) emulsion on the pH of human skin surface (pH(ss)) and stratum corneum (SC; pH(sc)) were evaluated in vivo. METHODS: The AHA O/W emulsion was applied to an area on the volar forearm of male volunteers (n = 12), and then wiped off after 10 min. Prior to application and over the following 3 h, the pH(ss) was measured. We used glass electrode measurements and time domain dual lifetime referencing (tdDLR) with luminescent sensor foils. In another experiment (n = 5), the impact of the AHA O/W emulsion on the pH(sc) gradient was measured by tape stripping of the SC of the volar forearm after application of the AHA O/W emulsion. RESULTS: Compared with pH(ss) values prior to treatment [5.2 ± 1.7 (tdDLR) or 4.8 ± 0.5 (electrode)], the pH(ss) was significantly reduced 10 min after application [4.0 ± 0.3 (tdDLR) or 4.1 ± 0.1 (electrode)] and the pH(ss) remained significantly reduced over the measurement period of 3 h [after 3 h: 4.4 ± 0.2 (tdDLR) or 4.5 ± 0.3 (electrode)]. The AHA O/W emulsion significantly reduced the pH(sc) even down to deep layers of the SC. CONCLUSION: After a 10-min application time, the 10% AHA O/W emulsion reduces the pH(ss) (for at least 3 h) and pH(sc) in deep layers of the SC.

Effect of prenatal testosterone administration on palmar dermatoglyphic intercore ridge counts of rhesus monkeys (Macaca mulatta).

Dermatoglyphic ridge counts of the prints of 59 rhesus monkeys (Macaca mulatta) whose mothers had been treated with injections of testosterone during their pregnancies were studied to determine the effect of the day the hormone began to be administered, the amount of hormone administered, and the number of days of hormone administration upon the dermatoglyphic variation of the offspring. Of the three hormone variables, only the day of beginning administration (STARTDAY) was significantly associated with dermatoglyphic variation, and its positive significance was demonstrated with the ridge counts of Area I on both the left and right hand, Area II of the left hand, and the total ridge counts of both hands. These results are discussed within the context of the timing of the dermatoglyphic window, and the differences in the findings between the monkey and earlier human studies are addressed.

Dermatoglyphic asymmetry and testosterone levels in normal males.

Dermatoglyphic prints and salivary samples were taken on a sample of 39 adult males. A statistical relationship between dermatoglyphic asymmetry and adult testosterone levels as measured in saliva was examined for seven dermatoglyphic variables by means of correlation, regression, and analysis of covariance, controlling for age and stature when necessary. The first two types of analyses indicated a significant effect of testosterone level upon the asymmetry of three dermatoglyphic variables: a-b ridge count, palmar pattern intensity, and the combined pattern intensity of palm and digits. Analysis of covariance, which examined the effect of testosterone level as a categorical variable, while holding age or stature constant, demonstrated the asymmetry of five variables to be significantly affected by testosterone level: radial digital count, digital pattern intensity, palmar pattern intensity, total digital ridge count, and the combined palmar and digital intensity. Although there is as yet only associational evidence linking levels of prenatal and secondary testosterone, the results of the present study lend support to the hypothesis that prenatal testosterone levels may have a significant effect on the development of dermatoglyphics.

Pedigree analysis of sucrose intolerance among Native Alaskans.

Sucrose intolerance, the inability to digest sugar, has been found to be unusually frequent among North Alaskan Inupiat. It is conjectured that this rare hereditary condition reached elevated levels due in part to the small, rather isolated population structure characterizing traditional Inupiat settlement patterns. An additional factor was likely to be a form of "selection relaxation" in which sucrose intolerance was not selected against during precontact times when the Inupiat diet consisted primarily of animal foods. An attempt was made to trace genealogical connections between pedigree containing cases of sucrose intolerance. This proved to be mostly unsuccessful due to insufficient information. It calls for researchers to make exerted efforts to obtain pertinent family history data along with extended pedigree records. Sucrose intolerance, while affecting relatively few persons, can lead to health problems, particularly if there is limited dietary choice. This is likely to be the situation among North Alaskan populations where sugar has become a major constituent in their acculturated diet.

Dermatoglyphic and anthropometric relationships within the Iñupiat (Eskimo) hand.

On the basis of earlier findings with Easter Islanders suggesting a positive correlation between dermatoglyphic variables and hand anthropometric measurements, the present study was designed to determine if such a relationship could be generalized to another population, namely, Iñupiat (Eskimo). Since some dermatoglyphic and anthropometric variables were available for both sides of the body, the extension of this study to explore the question of asymmetry was also possible. The Iñupiat sample numbered 142 male and 176 female adult inhabitants of five Alaskan North Slope communities. The major findings of this study included, for males, significant negative correlations between left arm length and digital ridge counts and positive relationships between the palmar variable of axial index and hand length on both hands. For females, the hand breadth/length index was negatively related to most of the digital variables. Very little definitive information regarding the relationship of the asymmetry variables between the two types of measures was ascertained.

Digital dermatoglyphics of three Amerindian populations of the Brazilian Amazonia: a further test of the field theory.

Finger ridge counts of three Amerindian populations of the Brazilian Amazonia (Suruí-Paitér, Kayapó-Xikrín and Suruí-Mudjetíre) were subjected to principal component analysis in order to verify the concept of developmental field (field theory). For both sexes, a clear tripartite divisioning (digit I, digits II-III, and digits IV-V) was obtained, corroborating results previously published for other populations.

Assortative mating in monozygotic twins.

This study investigated assortative mating in a series of monozygotic twins in terms of anthropometric variables. Initially the twins were analyzed independent of each other, and the results showed fairly clear homogamy among female MZ twins and their spouses, after correcting for age. Further, when stature was partialled out, several anthropometric measures remained significantly correlated. The results for male MZ twins and their spouses were not nearly so clear-cut. A second analysis treated the co-twins together, and once again, the female MZ sets tended to show assortative mate choice for stature while the male MZ twins/spouses were not significantly correlated. A follow-up analysis investigated whether husbands of the female twins were correlated to each other, and negative results were found for all of the 46 anthropometric variables. An apparent contradiction was resolved in the case of stature by regressing spouse stature against that of the co-twins. It was found that although each of the twins was assortatively mating, one member of the twin set consistently married a taller husband, but the difference was not constant. This had the effect of producing divergent regression lines.

Meaning of biodistance statistics: a test case using adult monozygotic twins.

Anthropometry, historically one of the primary research techniques in physical anthropology, has been widely utilized in biodistance studies. The complex genetic and environmental interaction that governs the expression of anthropometric dimensions, together with concerns over measurement error, have sometimes clouded the interpretation of biodistances based upon anthropometry. In this study, 51 pairs of adult monozygotic twins were analysed using discriminant analysis and Mahalanobis' generalized distance. Both male and female twins, grouped by first- versus second-born, displayed very small, statistically insignificant distances between groups. When literature estimates of intra-observer measurement errors were used as a frame of reference, the average absolute differences between the twin pairs were approximately twice the size of the measurement error estimates. The results of this study suggest that, first, the environmental effect upon the genetically influenced traits measured by anthropometry is not large enough to bring about significant multivariate differences between identical twin pairs; and, second, biodistance studies based upon anthropometry can be reliable so long as measurement error is minimized.

Topological description of Easter Islander palmar dermatoglyphics.

A sample of 594 Easter Islander palms was analyzed according to the topological method. Some suggestions for clarification of the topological approach were made, including clearer definition of the palmar triradii and substitution of the term "profile" for "formula." The frequency of Easter Islander profiles was compared against British and Australian Aborigine samples (Loesch, 1974; 1983a,b) and found to be significantly different for two of the ten most common combinations. The individual pattern elements, pattern intensities, a-b count, A-line exit, and atd angle were described, with population comparisons made when they were available.

Easter Islander palmar dermatoglyphics: sexual dimorphism, bilateral asymmetry, and family polymorphism.

The palmar prints of 297 male and female Easter Islanders were analyzed according to the Penrose and Loesch topological classification system. While the frequencies of most pattern elements were not found to differ significantly between the sexes, the placement of the axial triradius was found to be highly significant (P less than 0.01). Both males and females were found to exhibit considerable bilateral asymmetry in the a-b count and in the atd angle, but there was no significant difference between the sexes in the amount of asymmetry expressed. Family data for a small subset of the sample (51 individuals) were subjected to further statistical analysis, from which significant results (P less than 0.05) were obtained both on chi-square tests for frequency of pattern elements and ANOVA tests for a-b counts, atd angle, and A-line exit. The implications of these results are considered from a developmental perspective. It is suggested that a particular pattern combination (termed a formula) could be used to represent a default value and that other formulae might then be considered as deviations from this default value. Such variation, theoretically at least, might be traced to genetic influences or to the embryological environment present during the time of dermatoglyphic formation.

Dermatoglyphics of Easter Islanders analyzed by pattern type, admixture effect, and ridge count variation.

The adult Easter Island population was fingerprinted in 1965 as part of an overall study of their human biology. Major findings of the dermatoglyphic analysis are as follows. Digit and bimanuar percentages of patterns (arches, loops, and whorls) were similar to those observed in Europeans. However, in terms of total pattern type distributions, the Islanders had many more whorls and a correspondingly much higher Pattern Intensity Index than those found in European groups. This difference was even present, although in lesser magnitude, in Easter Islanders known to be admixed with Europeans. Corresponding to a high occurrence of whorls, Mean Total Ridge Count (TRC) was also notably high. An association between TRC as a measure of pattern size and incidence of patterns was clearly evident in several groups available for comparison.