Biomedical subjects
Publications and source records attributed to R Meyer.
Morphometrical results obtained on rat myocard by means of 2 different histological techniques (conventional and semithin slices) have been compared. For certain parameters the abovementioned techniques provided different values. For an exact estimation of all parameters of myocardial cells a combination of semithin sectioning with histochemical techniques is proposed.
The morphometrical alterations of heart muscle cells and their cytoplasm of rats were investigated during the postnatal development. Volume density of muscle cells and interstitium shows approximately constant values. Cell colume of muscle cells increased up to the 6th month, however, maxima and minima were observed during this period. Volume density of mitochondria doupled from the birth the the 6th months. Volume density of myofibrills increased poorly.
Biopsies of rectum carcinomas from 17 patients have been investigated by means of lights microscopical morphometric methods before and in the course of x-radiation therapy. According to the morphometric results, a x-ray dose of 2 000 rd is considered as being efficient, and 4 000 rad as an optimum dose.
The possibility of using modified formulas for determining the surface density of cellular membranes of the heart muscle cell was discussed, sarcoplasmic reticulum and particularly mitochondrial cristae being used as examples. By using modified formulas and different stages of magnification it could be possible to determine the surface density of critae also in such experimental conditions in which the mitochondrial cristae appear to be densely packed.
Comparative ultrastructural morphometric and physiological examinations of the rat's myocardium after swimming exercise, hypokinesia and hypobaric hypoxia show concurrence between morphometric and contractility parameters. Differences in the changes of cell organelles in general and of mitochondria and sarcoplasmic reticulum in particular observed in the experimental models of adaptation used provide a basis for making inferences as to different structural reaction patterns of the myocardial cell. Special importance is attached from the functional point of view to changes in the volume and membrane surface density of the longitudinal sarcoplasmic reticulum and in Golgi's apparatus. Different structural reaction patterns suggest different adaptation mechanisms of the myocardial cell.
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We report 5 cases of temporal arteritis associated with a diabetes whose good evolution under corticotherapy suggests a common pathogenesis. Several hypotheses can be formulated to explain the origin of the glycemic abnormality and to understand the way corticotherapy is effective. A moderate posology could at first have a hyperplasic effect on the insulin-secreting cells, and later on a favorable action on the vascular lesion and on an immunological disorder. Any definitive conclusion cannot be evolved yet. Only a more systematical study of the glycoregulation's abnormalities in the temporal arteritis will enable to answer the many remaining questions.
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Tn5-trp hybrid transposons have been constructed by insertion of a trpPOED Hind III fragment into an in vivo Tn5 internal deletion mutant or by substitution of trp for the internal Tn5 Hind III fragment. These hybrids are called, respectively, Tn409 and Tn410. Both Tn409 and Tn410 will transpose into lambda in the presence of a complementing Tn5 element. In the absence of a wild Tn5, lysogens carrying R1162::Tn409 and R1162::Tn410 plasmids will yield lambdatrp phages at less than six per cent of the complemented frequency. This reduction indicates that Tn409 and Tn410 lack a diffusible transposition function provided by wild Tn5 elements. However, the formation of lambdatrp phages without complementation is real. Most of these transducing particles contain Tn409 and Tn410 still linked to the carrier R1162 plasmid. This observation suggests that uncomplemented Tn409 and Tn410 elements mediate the formation of lambda-transposon-plasmid cointegrate structures. Thus, the missing transposition function may be involved in resolving these cointegrate structures to the final lambda::Tn409 or lambda::Tn410 product.
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Intracerebral involvement in Hodgkin's disease is an unusual complication. Only 28 cases have been reported. During the past twenty-four months, we have seen six patients with intracranial involvement. Five of the six patients were male and all had mixed cellular histology. We have found the cytocentrifuge examination of the cerebrospinal fluid, brain scan, angiography, and computerized axial tomography to be the most important diagnostic examinations. We feel that intracranial disease will be seen with increasing frequency as patients are living longer.
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Results obtained by three different electrophysiological methods delivered mainly oscillating potentials (independently of the type of organization of Physarum polycephalum) with an average period length of 1 min 21 sec. This value is in good statistical agreement with corresponding data for the periodical oscillation of the shuttle streaming (1 min 47 sec) and coincides also with the radial tensiometric contractile activity (1 min 34 sec). The investigation favours the hypothesis that ion fluxes across the cell membrane and perhaps between intracellular compartments may act as a trigger mechanism for a still unknown oscillator-system which controls cell movement phenomena in the acellular slime molds.
Glycerol has a rate and volume of distribution similar to urea. Thirty-six mM glycerol in the dialysate prevents the fall in serum osmolality but does not decrease symptoms or improve the vascular stability of patients on chronic hemodialysis. We suggest that the benefits of mannitol, sodium and glucose in preventing or reversing symptoms during chronic dialysis are due to their extracellular distribution.
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