Biomedical subjects
L Freedman
Publications and source records attributed to L Freedman.
Abduction of the arm in the scapular plane: scapular and glenohumeral movements. A roentgenographic study.
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Geometric morphometric study of population variation in indigenous southern African crania.
Much of our understanding of population variation in southern Africa is derived from traditional morphometric research. In the search for new perspectives, this paper reports on new geometric morphometric data examining cranial variation in 12 modern human populations from southern Africa. In total, 298 male Bantu-speaking individuals were studied. In addition, a small Khoisan (Khoikhoi and San) series was also examined. The purpose of this study was to investigate Khoisan-Bantu morphological similarities and differences, and to examine variation within both the Bantu-speaking and Khoisan populations. The three-dimensional coordinates of 96 landmarks were analyzed, using the shape-analysis software morphologika. Interpopulation variation was examined by calculating Procrustes distances between groups; a cluster analysis was then used to summarize phenetic relationships. A principal components analysis explored the relationships between populations; shape differences were visualized and explored using three-dimensional rendered models, and further interpreted using thin-plate splines. Morphological differences are present within and between the crania of Bantu-speaking and Khoisan individuals. The Khoisan demonstrate features (e.g., a pentagonoid vault, more rounded forehead contour, and a small and less prognathic face) that clearly distinguish them from Bantu-speaking populations. Although southern African Bantu-speaking populations are clearly closely related, they show population-specific features (e.g., the crania of more southerly populations (Xhosa, Southern Sotho, and Zulu) are characteristically more brachycephalic and less prognathic). This study suggests that differential admixture with adjacent Khoisan peoples has contributed to diversity within southern African Bantu-speaking populations.
Seasonal variation in the incidence of delirium among the patients of a geriatric hospital.
Delirium syndrome is common in the hospitalized elderly population. However, data on its numerous etiological factors are scarce. Clinical observations suggest that delirium incidence could be related to seasonality. In order to evaluate the seasonal influence on the incidence of delirium syndrome among the patients of a geriatric hospital, we performed a retrospective study reviewing the medical records of 5218 patients aged 65 years and older, who were hospitalized in three medical wards between the years 1991 and 1997. The diagnoses of delirium were made according to ICD-9-CM. Of the 4929 subjects enrolled, 3548 (72%) were referred for assessment to the psychiatric or neurologic specialist, because of acute changes in their mental or behavioral status. Of those patients, 312 (6.3%) were diagnosed with delirium at admission, and 234 (4.7%) developed delirium during their hospitalization. Statistical analysis of incidence revealed a seasonal variation, with higher rates in the winter than in the summer months (P<0.001). This study suggests a seasonal influence on delirium syndrome incidence and a possible etiological relation with seasonal factors like the light -dark cycle.
The influence of eye colour upon temporary threshold shift.
Controversy has arisen over the claim that melanin content of the iris as determined by eye colouration bears a direct relationship to susceptibility to temporary threshold shifts (TTS). A more comprehensive investigation of TTS has now been carried out which not only confirms the relationship but also indicates that earlier discordant results can be attributed to differences in methodology. The new evidence suggests that for stimulus intensities below 110 dB. (HTL re ISO, 1964) melanin content of the iris exerts its influence predominantly upon auditory adaptation while fatigue effects only become apparent at intensities above this level. The relevance of these findings to hearing conservation measures aimed at the prevention of noise-induced hearing loss is discussed.
Hyperthermia and radiation in the treatment of superficial malignancy: an analysis of treatment parameters, response and toxicity.
A total of 41 superficial tumours have been treated with radiation alone (21 lesions) or in combination with hyperthermia (20 lesions) in a non-randomized study on 16 patients. A minimum tumour heat dose in excess of 30 min equivalent at 43 degrees C was achieved in 46 of the 80 (57 per cent) hyperthermia treatments. Small lesions received better quality heat treatments and were more likely to achieve a complete response. There is a significant increase in the response of lesions treated with the combined modality compared with radiation alone (P less than 0.01). Similar results were obtained when matched lesions with internal controls were analysed separately. There was an increased incidence of severe skin reactions in the hyperthermia-treated group with the reaction tending to develop more quickly. There were three instances of late fibrosis in the hyperthermia group. There is a significant correlation between the severity of the skin reaction and the average maximum skin heat dose per treatment.