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Biomedical subjects

S R Pattyn

Publications and source records attributed to S R Pattyn.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

[Action of desoxyfructo-serotonin on Mycobacterium leprae. Results of inoculation of human biopsy specimens in the mouse after a year of treatment].

M. leprae, extracted from cutaneous biopsies of 4 out of 7 patients treated with DFS during one year at doses of 1000 to 1500 mg/day were injected in mouse foot pads. Bacterial multiplication was observed in each case. The purely bacteriostatic activity of DFS for M. leprae, previously observed in mice, is thus confirmed. The eventual place of DFS in the therapy of leprosy is discussed.

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PubMedDate not supplied

Correlation viability/morphology in Mycobacterium leprae.

The present study regards the correlation between the percent of viable M. leprae (as determined by the mouse foot pad technique) and the quantitative ultrastructural analysis of M. leprae cells in 6 armadillo's samples and 1 nude mouse foot pad. The quantitative ultrastructural study of 3 LL patients and 1 M. leprae-infected nude mouse was correlated to the Morphological Index. The results show that most M. leprae cells with continuous undeformed cell walls, continuous symmetric membranes, ribosomes and fibrilar nucleoids are viable bacilli. Some cells with the above ultrastructural pattern may be dead bacilli that did not yet enter the macrophage-induced degradative process that results in the disposal of the bacteria. Our results also show that degenerating M. leprae cells largely predominate in most samples studied. This means that, even in the absence of anti-leprosy treatment, dead M. leprae cells accumulate in the host's tissues. This point has to be taken into account in the calculation of the generation time of M. leprae in vivo, the dynamics of the leprosy bacillus in susceptible hosts being influenced by the simultaneous occurrence of growth, death and degradation. Since known facts in regards to the physiology of bacterial membranes make it difficult to accept the PAS-symmetric membrane of viable M. leprae as the membrane of growing bacilli, a search of M. leprae cells with asymmetric membranes was undertaken in appropriate samples from nude mice. Several M. leprae cells with normal ultrastructure and Thiéry-asymmetric membranes were found in the foot pads of one mouse. Although this observation must be confirmed in another sample, it suggests that M. leprae would not be an exception to the general concept that the membranes of all growing Gram-positive bacteria have PAS-positive components located only in the outer layer. The M. leprae cells that have normal ultrastructure and symmetric membranes and that are viable would represent some sort of resting cells, that is, living but not growing bacteria. All the, 11, 263 individual bacillary profiles scored in the ultrastructural study included in the present study exhibited the micromorphological characteristics of acid-fast bacteria.

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PubMedDate not supplied

Mouse foot pad technique for evaluation of drug resistance of M. leprae and other laboratory techniques to be used in leprosy control programmes.

There is no need for mouse foot pad facilities for drug sensitivity testing to start leprosy control programmes, since the size of the problem is known. There will however be a need for some mouse foot pad work in later stages, to document relapse cases and test relapse strains for drug sensitivity. Arrangements should be made to ship such specimens to existing laboratories. There is more need however for facilities for monitoring drug intake. Finally, where nonexistant, there may be incidentally some need for quality control of imported drugs, which can be solved through collaboration with existing facilities in other countries.

Dapsone↗
PubMedDate not supplied

Growth of mycobacteria in relation to the pH of the medium.

The influence of pH on the growth of mycobacteria on Loewenstein and Dubos OAA media was studied with 56 strains belonging to 10 species of rapidly growing and 16 species of slowly growing mycobacteria. pH gradients were obtained by the use of McIlvaine's citrate and Sörensen's citrate buffer. The sensitivity of mycobacteria at different pH values of the medium was independent of the culture medium and buffer used. Minimal, maximal and optimal pH values were specific for each species, all strains of the same species producing identical results. Some slowly growing mycobacteria such as Mycobacterium lepraemurium developed within a very narrow optimal pH range: between 5.8 and 6.1. Other species developed over a wide optimal pH range, e.g. M. nonchromogenicum: from 5 to greater than 7.4. For slow growers, in general, with the exception of M. lepraemurium, optimal pH was between 5.8 and 6.5. In general, rapidly growing mycobacteria developed over a wider pH range of more than 2 units. All strains, with the exception of M. chelonei, developed optimally between pH 7 and 7.4. For M. chelonei, as for slower growing species, the optimal pH was between 5.4 and 6.5. Taxonomically related species such as M. tuberculosis and M. bovis, M. kansasii and M. gastri, M. microti and M. bovis BCG, and M. vaccae and M. parafortuitum, were inhibited or stimulated at identical pH values. This specificity constitutes a supplementary taxonomic character. At certain pH values, some species otherwise difficult to separate may be differentiated: e.g. M. avium, not growing at pH 4.6, is distinguished from M. scrofulaceum which does grow at pH 4.6. For routine diagnostic purposes, Loewenstein Jensen medium at pH 7 is not optimal; Ogawa medium, with its pH of 6, is more appropriate.

Culture Media↗