Biomedical subjects

A M Malbouisson

Publications and source records attributed to A M Malbouisson.

3 recordsLinked to original sources

PubMed1985

Axonal microtubules: a computer-linked quantitative analysis.

Employing current computer-aided morphometric techniques, axonal microtubule density was determined for the rat sural nerve. Analysis of extensive data showed that while microtubule number increases with axon size, the increase is not directly proportional. Thus the relationship between microtubule density and axonal size is inversely related, so that microtubule density is greater in smaller axons than in larger axons. When a proximal and distal site, separated by 2 cm, were compared for microtubule density there was no significant difference, using pooled data for all fibre diameters. The results are interpreted in terms of our present knowledge of axonal-microtubule quantitative relationships, which is reviewed.

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PubMed1985

Axonal degeneration in large and small nerve fibres. An electron-microscopic and morphometric study.

Using computer-aided morphometric methods, axonal degeneration following nerve crush was analysed to reassess whether small fibres degenerate before large fibres or vice versa, or simultaneously. Axonal microtubule density was used as the criterion for determining the extent of fibre degeneration. Axonal areas and axonal microtubule numbers were recorded from a large sample of myelinated fibres in the right unoperated rat sural nerve and distal to crush in the left sural nerve. Both samples were divided into small and large fibre groups, according to axonal areas. Statistical analysis of the data confirmed a significant loss of microtubules from the left crushed nerve fibres but no significant difference in the relative loss of microtubules from small and large fibres. It is concluded, therefore, that in Wallerian degeneration, axonal breakdown, as assessed by microtubule loss, occurs simultaneously in small and large fibres. The findings are related to the electrophysiological changes which occur in Wallerian degeneration.

Animals↗

PubMed1984

The non-directional pattern of axonal changes in Wallerian degeneration: a computer-aided morphometric analysis.

Wallerian degeneration was investigated to determine whether axonal changes occur progressively in a somatofugal or somatopetal direction or simultaneously along the length of the axon. Microtubule density was used as a measure of the extent of axonal degeneration and was assessed by a computer-aided analysis of electron micrographs. The left sural nerves of ten rats were crushed and 30 hours later axonal areas and axonal microtubule numbers were recorded from a large sample of axons at two sites 1 cm and 3 cm distal to the crush. The same recordings were made from the right unoperated nerve at two comparable sites. Statistical analysis of all the data provided no evidence for a somatofugal or reverse direction of degeneration. It is concluded therefore that in Wallerian degeneration axonal changes, as indicated by microtubule dissolution, occur simultaneously along the length of the axon. It is proposed that to interpret the conflicting published data on the direction of fibre degeneration, Schwann cell changes (e.g. myelin ovoid formation) and axonal changes (e.g. microtubule dissolution) should be considered independently since they have different aetiological mechanisms which may account for the differing experimental results reported.

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