Variations of the paranasal sinuses in Melanesians as observed by CT.

Studies have reported the incidence of anatomical variants of the paranasal sinuses for specific populations with a view to helping surgeons avoid possible complications during functional endoscopic sinus surgery. Some have found significant variation when comparing different populations. The current study has used computed tomography (CT) scans to observe variations in the paranasal sinuses in a non-random sample of museum skulls of Melanesians, a racial group that has not previously been studied in this respect. The incidence of variants found were: agger nasi cells 59.5%, concha bullosa 41.5%/o, Haller's air cells 31.7%, internal carotid artery bulge in the sphenoid sinus 23.8%/, supraorbital cells 16. 7%, paradoxical curvature of the mid-dle turbinate 7.5% and pneumatization of crista galli 7.1%.Because of contradictory findings in the literature as to the incidence of such variations between racial groups the authors are able to make only limited meaningful comparisons between their subjects and other such groups.

Sexual dimorphism in deciduous crown traits of a European derived Australian sample.

Sex determination of juvenile skeletal remains is a problematic area affecting physical anthropology, forensic science and archaeology. Sexual dimorphism in the morphometric crown traits of the deciduous dentition may be used to help resolve this issue. Dental stone casts from a European derived Australian sample (n=151) were used to investigate variation within crown traits of the deciduous canine and molars. The metric traits investigated were crown size, trigonid size and talonid size. The morphological features included Carabelli's trait and molar cusp number. Metric crown traits were significantly larger in males (p<0.05). The morphological crown traits were not significantly different between the sexes. The largest degree of sexual dimorphism was 11.11% in the trigonid mesiodistal diameter of the first deciduous molar. This is the first recording of the measurement in a European derived sample. Two multivariate statistics, linear functional discriminant analysis and binary logistic regression, were used to determine the success rate of sex classification from the crown traits. The most suitable was linear functional discriminant analysis, however similar results were found when using binary logistic regression. When using all variables investigated in this study, sex could be classified with accuracy of 70.2% from linear functional discriminant analysis (cross validated). The mandibular teeth had greater sexual dimorphism, classifying sex correctly 74.8% of the time compared to maxillary variables that had a success rate of 55.6%. Our results have shown that morphometric crown traits in the deciduous dentition can be used to classify sex of juvenile skeletons (11 months to 12 years) of European descent from linear functional discriminant analysis with accuracy between 70.2% and 74.8%.

A comparison of cortical bone thickness in the femoral midshaft of humans and two non-human mammals.

Fragments of bone shafts that lack diagnostic features can be difficult to identify as human or non-human-an important task in forensic science and archaeology. Some workers have found the thickness of cortical bone in the shaft to be a useful distinction, although the sparse literature in the field is contradictory in how this may be applied. The aim of the present study was to determine whether any difference is discernible between humans, kangaroos and sheep (mammals whose remains are commonly confused with those of humans in Australia) at the femoral midshaft, with a view to a larger-scale analysis if differences were discovered. Cross-sections at the midpoint of the shaft were measured to determine the diameter of the whole shaft and the medullary cavity on each bone; an index describing cortical thickness relative to shaft diameter was calculated. Statistically significant differences were found between all three groups, with humans showing the thickest cortical bone, and sheep the thinnest. These differences may be linked to a higher load on the human femur, due to a larger body mass carried on two legs, as opposed to the sheep's four. Further work now needs to be carried out to determine if differences are present when comparing multiple sites on the skeleton, and between non-human mammals of different sizes.

Patterns in dental enamel hypoplasia by sex and age at death in two archaeological populations.

AIMS: Levels of enamel hypoplasia in past populations are frequently used to study health. However, few studies have looked at patterning in the occurrence of different types of hypoplasia. In this pilot study, skeletal remains from an Iron Age tomb at Pella in Jordan were analysed for the presence of linear and pit enamel hypoplasia, to investigate enamel hypoplasia aetiology by comparison of the results obtained for adults and juveniles, and females and males. METHODS AND RESULTS: The proportion of individuals with enamel hypoplasia was determined for males and females and for adults and juveniles using the F.D.I. Developmental Defects of Enamel (DDE) Index. Although males and females had a similar percentage of individuals affected, females had a higher prevalence of enamel hypoplasia per tooth than males. Adults had a higher prevalence of enamel hypoplasia than juveniles. In particular, adults had a higher prevalence of linear enamel hypoplasias and pit enamel hypoplasia arrays, but a similar prevalence of single pit enamel hypoplasia when both the permanent and deciduous dentitions were considered. These differences were largely due to different patterns and frequencies of enamel hypoplasia in deciduous teeth compared to permanent teeth. CONCLUSIONS: The different patterns of occurrence of the various forms of hypoplasia observed in this study imply that single pits may have a different aetiology to linear enamel hypoplasias and pit arrays. By investigating similar patterns in other archaeological populations, we may develop a better understanding of the specific causes of particular types of enamel hypoplasia, and may be able to more meaningfully interpret enamel hypoplasia data from past populations.

Dental enamel hypoplasias and health changes in the Middle Bronze Age - Early Iron Age transition at Pella in Jordan.

Dental enamel hypoplasias are increasingly being used in epidemiological studies as indicators of health within both modern and prehistoric populations. This symptom of growth disruption is used here to examine possible changes in health occurring at the transition between the Bronze Age and Iron Age in Jordan, through examination of enamel hypoplasias in skeletal remains from two tombs at the archaeological site of Pella. A small but not statistically significant difference in the prevalence and frequency of hypoplastic defects was found between the two time periods. These results suggest that the political and economic changes occurring at this time were not sufficiently stressful to cause a dramatic deterioration in health at the onset of the Early Iron Age.

The value of infracranial nonmetric variation in studies of modern Homo sapiens: an Australian focus.

The value of quantitative infracranial nonmetric variation is examined in the study of population relationships by using samples from populations originating from five major geographic regions: Australia (two populations), Africa, East Asia, Europe, and Polynesia. According to the nonspecificity hypothesis, there are no distinct large classes of genes affecting one group of attributes exclusively; thus infracranial nonmetric traits should compare with other osteologic data sets in addressing questions of population relationships. By using the mean measure of divergence, infracranial nonmetric traits are shown to be useful in separating populations, particularly when using female and pooled-sex samples. The two Australian female samples (New South Wales coastal Australian and South Australian Aboriginals) are shown to be closer than any other two samples. The picture of intrapopulation and interpopulation variation in infracranial nonmetric traits is extended and clarified. Distance studies with infracranial nonmetric traits are possible but more illuminating if the sexes are first separated. Infracranial nonmetric variation does extend the knowledge of human population studies in yielding biologically meaningful results relating to development and ontogeny.

Improved outcome at 28 days of age for very low birth weight infants treated with a single dose of a synthetic surfactant.

Two identical double-blind, controlled, randomized trials were initiated to determine whether the administration of a single 5 ml/kg dose of a synthetic surfactant (Exosurf Neonatal), soon after the delivery of infants with birth weights 700 to 1350 gm, would improve rates of survival without bronchopulmonary dysplasia. Both trials were terminated before enrolling their planned sample sizes because of the availability of Exosurf under the provisions of a Treatment Investigational New Drug program. We report the combined results of these trials. Study infants were stratified according to birth weight and gender before random assignment to a treatment regimen. One hundred ninety-two infants received Exosurf and 193 received an air placebo. The study groups were similar when a variety of demographic features describing the mothers, their pregnancies, the circumstances of the births, and the infants were compared. Exosurf-treated infants required significantly less oxygen and respiratory support during the first 3 days of life in comparison with the air-treated infants. Fewer infants in the Exosurf group had pulmonary interstitial emphysema (26 vs 13; p = 0.028). In the Exosurf group, there was a significant reduction in the combined outcome, neonatal death or survival with bronchopulmonary dysplasia (57 vs 39; p = 0.042), and there was a significant increase in rates of survival without this disease (128 vs 137; p = 0.042). There were no differences between treatment groups in the incidences of a variety of complications of prematurity, including apnea, patent ductus arteriosus, intraventricular hemorrhage, and necrotizing enterocolitis. We conclude that improvements in respiratory physiology after a single prophylactic dose of Exosurf result in an increased likelihood of neonatal survival without bronchopulmonary dysplasia.

Pulmonary function following positive pressure ventilation initiated immediately after birth in infants with respiratory distress syndrome.

Cardiopulmonary function following positive pressure ventilation, initiated immediately after birth, was evaluated in 10 very low birthweight infants with respiratory distress syndrome (RDS; RDS infants). Multiple gas rebreathing methodology was used to measure functional residual capacity (FRC), diffusing capacity of the lung for carbon monoxide (DLCO) and effective pulmonary capillary blood flow (Qeff) at 2, 24, and 72 hr of age. Cardiopulmonary function variables were also measured at 2 hr of age in 10 infants of similar birthweight who did not have RDS (non-RDS infants). In RDS infants, mean FRC at both 2 hr of age (15 mL/kg or 0.42 mL/cm) and 24 hours of age (20 mL/kg or 0.54 mL/cm) was less than published predicted values for healthy infants and significantly less than values in non-RDS infants at 2 hours of age (29 mL/kg or 0.8 mL/cm). By 72 hr of age, mean FRC in RDS infants rose to predicted. At 2 and 24 hours of age, mean Qeff in RDS infants (41 and 38 mL/min/kg, respectively) was below predicted, as well as below the value observed in non-RDS infants at 2 hr of age (62 mL/min/kg). in RDS infants. DLCO remained well below published predicted values throughout the first three days of life. We conclude that early aggressive respiratory therapy does not result in the establishment of normal lung volumes during the first day of life, but it does so by 3 days of age. However, in spite of intubation immediately after birth and the application of continuous positive pressure ventilation during the first 3 days of life, very low birthweight infants with RDS continue to have significant alteration in lung function, evidenced by impaired diffusing capacity of the lung and low arterial-alveolar oxygen tension ratios.