Dietary modifications alone do not improve bone mineral density in children with idiopathic hypercalciuria.

Prior cross-sectional studies have demonstrated an association between hypercalciuria and low bone mineral density (BMD) in children and adults. However, the natural history of BMD in children with hypercalciuria and its response to therapy has not been evaluated. The objective of this retrospective study was to determine the change over time in lumbar (L1 - L4) BMD Z-score measured on sequential DXA scans in 19 children with hypercalciuria treated with dietary recommendations without (n = 12, Group A) and with citrate (n = 7, Group B). The mean lumbar bone density Z-score/year decreased in Group A (-0.11 ±/0.41) indicating that children with hypercalciuria lose L1 - L4 BMD over time. In contrast, the L1 - L4 BMD Zscore/ year increased in Group B (0.19 ± 0.38) suggesting that pharmacologic therapy may reverse this trend. Similarly 75% of patients in Group A, but only 29% patients in Group B had a decrease in L1 - L4 BMD. There was a definite, although not significant, trend towards improved mean bone mineral density Z-score per year and a lower percentage of patients with a decreased Z-score in hypercalciuric children treated with potassium citrate. Our findings suggest the possibility that dietary recommendations alone is not adequate as the bone mineral density of children with hypercalciuria will decrease over time, potentially increasing the risk for osteoporosis as an adult.

Aboriginal health.

Improving the health of Australian Aborigines remains a challenge for health care professionals. Understanding the meaning of the term health is central to this issue. There are cultural differences that must be considered, and here the traditional Aboriginal view of health is compared with that of the World Health Organization.

Management of the airway in oral and oropharyngeal resections.

A tracheostomy is the traditional method of maintaining an airway after major oral and oropharyngeal resections. Postoperative endotracheal intubation was used for 19 patients who underwent major oral and oropharyngeal resections over a 3-year period at the Royal Adelaide Hospital. This appears to be a safe alternative to tracheostomy if intensive care facilities are available.

The use of State and hospital-based cancer-registry data to describe the epidemiological and clinical characteristics of laryngeal cancer in South Australia.

State and hospital-based cancer registries can be complementary sources for data that describe the general epidemiological and clinical features of cancers in specific populations. This has been illustrated with data on laryngeal cancer from registries in South Australia. The data were sufficiently detailed to indicate: trends in incidence by calendar year, age, sex, place of residence and country of birth; the distribution of cases by the subsite of the tumour, the histological type and grade, and the pretreatment clinical stage of the cancer at diagnosis; the complaints of patients at presentation; the modes of treatment by the stage of the cancer; and case-survival rates, both over all and as related to the subsite of the tumour, the sex and the stage of disease. Data also were available to indicate the increased risks of disease that were associated with tobacco smoking and alcohol consumption. The findings broadly are consistent with the results of previous epidemiological studies and show the utility of the combined use of state and hospital registry data to describe the general features of cancers in local populations.

The membrane as an environment of minimal interconversion. A circular dichroism study on the solvent dependence of the conformational behavior of gramicidin in diacylphosphatidylcholine model membranes.

The conformation of gramicidin in diacylphosphatidylcholine model membranes was investigated as a function of the solvent in which peptide and lipid are initially codissolved. By use of circular dichroism it is demonstrated that, upon removal of the solvent and hydration of the mixed gramicidin/lipid film, it is the conformational behavior of the peptide in the organic solvent that determines its final conformation in dimyristoylphosphatidylcholine model membranes. As a consequence, parameters that influence the conformation of the peptide in the solvent also play an essential role, such as the gramicidin concentration and the rate of interconversion between different conformations. Of the various solvents investigated, only with trifluoroethanol is it possible directly to incorporate gramicidin entirely in the beta 6.3-helical (channel) configuration. It is also shown that the conformation of gramicidin in the membrane varies with the peptide/lipid ratio, most likely as a result of intermolecular gramicidin-gramicidin interactions at higher peptide/lipid ratios, and that heat incubation leads to a conformational change in the direction of the beta 6.3-helical conformation. Using lipids with an acyl chain length varying from 12 carbon atoms in dilauroylphosphatidylcholine to 22 carbon atoms in dierucoylphosphatidylcholine, it was possible to investigate the acyl chain length dependence of the gramicidin conformation in model membranes prepared from these lipids with the use of different solvent systems. It is demonstrated for each solvent system that the distribution between different conformations is relatively independent of the acyl chain length but that the rate at which the conformation converts toward the beta 6.3-helical configuration upon heating of the samples is affected by the length of the acyl chain.(ABSTRACT TRUNCATED AT 250 WORDS)