Adult North American Research Articles

Vertical and Horizontal Proportions of the Face in Young Adult North American Caucasians

Farkas, Leslie G. M. D., F. R. C. S.(C), D. Sc; Hreczko, Tania A. Ph. D.; Kolar, John C. Ph. D.; Munro, Ian R. M. B., B. Chir., F. R. C. S.(C)

Short-term dietary selenium restriction in young adults: quantitative studies with the stable isotope 74SeO3(2-).

A 45 d metabolic study was carried out in four young adult male North American residents consuming a controlled diet based on an amino acid mixture. During the initial 10 d, total daily selenium intake was adjusted to 107.7 (SE 0.1) microgram/d, which was reduced to 11.4 (SE 0.1) microgram/d for the remaining 35 d. Two doses of a stable isotope (74SeO3(2-)) were administered orally in the post-absorptive state on days 4 and 39 of the study. Se balance (faecal + urinary excretion) as well as stable isotope excretion studies were carried out for the entire 45 d period; blood plasma and erythrocyte Se concentrations were also monitored. Plasma Se concentrations (microgram/ml) fell progressively from the initial value of 0.132 (SE 0.007) to 0.083 (SE 0.008) at the end of the study. The erythrocyte concentrations of Se did not vary in a consistent manner (average value for the entire study 0.147 (SE 0.002) microgram/ml). Faecal excretion of unenriched Se decreased from 66 (SE 6) microgram/d for days 1-10 to 10.2 (SE 0.8) microgram/d for days 14-40. Mean urinary excretions of the unenriched Se were 43.9 (SE 2.8) microgram/d (days 1-10) and 26.9 (SE 4.6) microgram/d (days 14-40). Total balance (intake-faecal excretion-urinary excretion) for unenriched Se was (microgram/d):-18 (SE 7) days 10-19, -17 (SE 2) days 19-39, -5 (SE 1) days 38-45. Fractional absorption of the ingested label was 0.529 (SE 0.032) and 0.542 (SE 0.038) for the Se-adequate and Se-restricted phases of the study. However, urinary excretion of the absorbed label was reduced from 6.57 (SE 0.73)% for day 1 of the Se-adequate phase to only 3.32 (SE 0.26)% for day 1 of the Se-restricted phase. Similar observations were also made for day 7 of each phase. These findings indicate that immediate contribution of ingested Se to the urinary Se pool is small.

Dynamics of selenite metabolism in young men: studies with the stable isotope tracer method

Dynamics of selenite metabolism in young adult North American men were studied using an amino acid diet and the stable isotope tracer methodology during a short-term selenium replete-restriction phase. During the initial 10 days subjects consumed the diet providing a total daily selenium intake of 107.7 ± 0.1 µg mostly as selenite. This was followed by selenium restriction at 11.4 ± 0.1 µg/day (as impurities from diet components) for the next 34 days. Kinetic studies with the stable isotope tracer 74SeO32− were carried out on days 4 and 39 of the study. Kinetics of excretion of the tracer in feces and urine were followed from which body retention curves were constructed. The retention curves were resolved into two exponential decay components with half-lives of 2.4 ± 0.3 and 162 ± 9 days (mean ± 1 SEM), respectively. Retention data and urine isotope enrichment curves were combined to determine dynamics of changes in the apparent body pool size for selenite (10.4 mg at t → ∞) as well as rates of turnover for this parameter.

Speaker Race Identification of Selected Adult North American Indians

Speaker Race Identification of Selected Adult North American Indians

Asymmetries in nostrils and the surrounding tissues of the soft nose--a morphometric study.

Seven measurements and two qualities of the soft nose and nasal bridge were recorded in 156 healthy young adult North American Caucasians. Nostril-type asymmetries and alar base dislocations (31 and 38 of 156, respectively) were associated with other minor nasal disfigurements more often than symmetrical nares or alar base levels. A true alar base dislocation between alae of the same shape was distinguished from pseudodislocation caused by differing alar configurations (two-thirds of cases) or configuration differences along with dislocation (one-third of cases). Columellar deviations, columellar length asymmetry, and alar base dislocations were more frequently to the left, whereas nasal bridge deviations and septal dislocations were more often to the right. On the left side the extent of columellar deviation (5.9 degrees) and degree of alar base dislocation (1.5 mm) were significantly greater than on the right (4.0 degrees, p less than 0.05, and 1.0 mm, p less than 0.01, respectively). Quantitative analysis of the relationship of the minor nasal disfigurements offers valuable data for both surgeons and clinical geneticists.

The site of the dipsogenic action of angiotensin II in the North American opossum

Adult North American opossums ( Didelphis virginiana), predominantly nocturnal water drinkers, were found to respond by drinking to water deprivation, cellular dehydration produced by intravenous infusion of hypertonic saline, and to both intravenous and intracerebroventricular administration of angiotensin II (AII). by taking advantage of the absence of the corpus callosum, an anatomical characteristic of the marsupial, we removed the subfornical organ and implanted a cannula into the anterior third ventricle under direct visual guidance. In these animals: (1) spontaneous drinking, and responses to water deprivation and cellular dehydration were unaffected; (2) after a postoperative period of unresponsiveness, attenuated and unreliable responses only to high doses of intracerebroventricular AII could be elicited; and (3) the dipsogenic effect of intravenous AII was abolished. We conclude that the subfornical organ is necessary for the physiologically appropriate effect of AII on drinking but that, in the absence of the subfornical organ, the brain can mediate the dipsogenic effect of intracranially administered AII, although the physiological significance of the latter phenomenon is unclear.

An evaluation of the soft-tissue facial profile in the North American black woman

I t has become apparent within the past several years that significant variations do occur among and between individuals of different racial origins. Reports of interracial and intraracial investigations concerning anthropologic, physiologic, psychologic, cultural, genealogic, and various other areas of study are becoming increasingly prevalent in the literature. Among the various races that have been investigated, the black race has been examined to a moderate degree, originally through early anthropologic research and more recently through cultural and genealogic investigations. In the field of orthodontics, the North American black has been examined primarily through radiologic, photographic, and clinical methods, including evaluations of dentoalveolar study models. Of these studies, it is striking that there exists very little formal information fundamentally concerned with an evaluation of facial esthetics in the North American black. With the increasing number of North American blacks seeking professional treatment from the orthodontist, the oral and maxillofacial surgeon, the plastic and reconstructive surgeon, the otolaryngologist, and the maxillofacial prosthodontist, it has become apparent that there is a need to determine what constitutes a pleasing and/or a nonpleasing face for members of the North American black population. This information could become an integral part of the diagnostic armamentarium for these and other professionals who deal both directly and indirectly with changing the natural contours and profile outline of the face. The purpose of this study is to evaluate the responses of several white and black members of the orthodontic specialty to preselected soft-tissue facial profile outlines in the North American black woman. Specific questions examined in this study include: 1. What is the opinion among orthodontists of what is considered a pleasing and/or a nonpleasing facial profile for the adult North American black female? 2. Do profile preferences differ according to the race of the orthodontist? 3. Is there a significant relation between profile preferences and certain facial characteristics and patterns? 4. Upon what criteria are these profile preferences based?