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S Alt

Publications and source records attributed to S Alt.

13 recordsLinked to original sources
PubMed2001

Peripheral microcirculation during pregnancy and in women with pregnancy induced hypertension.

During pregnancy the cardiovascular system undergoes several changes so as to adapt the maternal organism to the strains of pregnancy. These adaptations can assume a pathological development in persons with a previous history of cardiovascular problems. On the other hand the absence of these adaptations may lead to a pathological course of pregnancy. Pregnancy induced hypertension (PIH) may be such a pathological development due to maladaptation. The causes are for the most part unknown. For some time it has been assumed that it is due to microcirculatory disorders. Using periungual capillary microscopy the present study prospectively investigated the changes in peripheral microcirculation during pregnancy focussing on pregnancy induced hypertension. Sixty-seven women with a normal course of pregnancy and 28 women with pregnancy induced hypertension were evaluated. Throughout the prospective study 3 examinations were performed during pregnancy and one during childbed. The women who developed a PIH were registered during the third trimester. Erythrocyte velocity at rest and vascular reagibility of capillaries following a 3 minute ischaemia were evaluated. In the course of pregnancy a significant increase of approximately 30% in erythrocyte velocity could be observed. Interpolation to obtain the best strait line result demonstrates that it is a continuous increase. Erythrocyte velocity returns to normal in the course of 14 weeks post partum. Due to a physiological vasodilatation during pregnancy, vascular reaction to ischaemic stress significantly decreases. During childbed these changes return to normal. Examinations on women with pregnancy induced hypertension not only showed a significant reduction of microcirculation under resting conditions but also a different pattern of reaction to ischaemic stress. Erythrocyte velocity under resting conditions lies 36% below normal values. Furthermore the distinctly shortened hyperaemic period indicates a hightened sensitivity to vasoconstrictive substances in women with PIH. While taking into account the clinical data a positive correlation with the severity of the illness was able to be established.

Adult↗
PubMed1998

The period gene controls courtship song cycles in Drosophila melanogaster.

We developed a technique that assists in objective identification of pulse and sine components in the Drosophila melanogaster courtship song. The song was recorded digitally and subjected to wavelet analysis, which decomposed the signal into a series of bands of decreasing frequency in which acoustic power appeared as a function of time. This time-frequency analysis expresses characteristic 'fingerprints' of the pulses, which appear in all frequency bands, and characteristic 'fingerprints' of the sine song, which appear only in the band containing its frequency. Means of the interpulse intervals (IPIs) for each second of 10-min recordings of song in which pulse singing occurred constituted an irregularly sampled time series, intractable to common spectral analysis techniques. Therefore, we took the discrete Fourier transform of this series, which retained all the spectral information in the Fourier coefficients, and used the inverse Fourier transform of these coefficients to yield a new series that was regularly spaced, with an estimate of IPI for each second in the interval. We observed an IPI period of 67.9 s in wild type, 31.1 s in per0, 45.9 s in pers, and 72.0 s in perL. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1996

T lymphocytic and immature macrophage alveolitis in active pulmonary tuberculosis.

The phenotype of bronchoalveolar cells from 11 healthy subjects and from affected and unaffected lungs of 15 patients with pulmonary tuberculosis (PTB) was determined. An immature macrophage alveolitis was found in the affected lung and the unaffected lung versus controls as determined by morphology and peroxidase activity. T lymphocytic alveolitis also was found in the affected but not the unaffected tuberculous lung compared with healthy controls. The majority of alveolar lymphocytes in unaffected and affected PTB lungs were T cells expressing the alpha beta T cell receptor. Alveolar T cells from both unaffected and affected lungs were activated, as determined by increased expression of CD69 and HLA-DR. Interleukin-2 receptor (IL-2R alpha) expression was, however, unchanged on alveolar lymphocytes from affected lung and was decreased in the unaffected lung. Thus, activated T lymphocytes and immature macrophages in the tuberculous lung are basic to the local immunopathogenesis of PTB.

Adult↗