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Biomedical subjects

W De Coster

Publications and source records attributed to W De Coster.

At least 19 recordsLinked to original sources
PubMed1994

The phototrichogram: analysis of some technical factors of variation.

Photographic methods for hair evaluation are frequently proposed as an alternative to more invasive methods (trichogram or biopsy). The reliability in terms of quantitative follow-up of hair growth has not been evaluated properly. We report results of comparative studies of scalp hair evaluation with various photographic methods. Statistically significant findings were a better detection of scalp hairs using the original enlargement x 3 as compared to x 2 (212 vs. 167 hair follicles/cm2) and a more acceptable estimate of linear hair growth rate with 'scalp immersion proxigraphy' (SIP) (0.317 mm/day) as compared with classical phototrichogram pictures where this variable was underestimated by 30% on average (0.27 mm/day). SIP-generated linear hair growth rates were very close to the micrometric method (0.37 mm/day). Therefore SIP x 3 images appear preferable for hair growth monitoring during clinical trials.

Alopecia↗
PubMed1989

Evaluation of dowel space preparation on the apical seal using an image processing system.

The effect of post preparation on the apical seal of endodontically treated specimens was studied. The canals prepared in bovine bone were instrumented and obturated using five obturation techniques: the silver point technique, the lateral condensation of gutta-percha technique, the warm vertical condensation of gutta-percha technique, the Hygenic Ultrafil injection system and the Obtura technique. In addition to these five control groups, the five experimental groups were also subjected to post preparation. In the latter group, the gutta-percha was removed with an engine-driven root canal reamer 48 hours after obturation. Both the control and experimental groups were suspended in a 0.5 per cent crystal violet solution for 48 hours. After dye penetration, the specimens were immersed in liquid nitrogen and then split longitudinally. Linear measurements of the resultant apical dye leakage were determined by image processing. For each obturation technique, all specimens in both the control and experimental groups were recorded if they showed leakage. Using Fisher's exact probability test, it was shown that there was no significant difference between the obturation techniques used.

Animals↗
PubMed1987

Influence of isaxonine on reinnervation of the rat gastrocnemius muscle.

Isaxonine is reported to have a favourable effect on nerve regeneration. The histological and histochemical changes were compared in the gastrocnemius muscles of 20 rats, in which the left sciatic nerve was frozen-crushed for 10 s at the level of the buttock. The animals received a daily dose of intraperitoneal isaxonine and ten others the solvent only. After 8 weeks small type grouping was seen in rats receiving solvent only and large type grouping in rats treated with isaxonine. After 10 weeks a checkerboard pattern of the fibre types was observed in the muscles of animals receiving solvent only but fibre type grouping was present in those treated with isaxonine. This experiment indicates that isaxonine prevents synaptic remodelling by suppression of the redundant nerve endings from additional axons, which have regenerated more slowly, in making contact with motor endplates.

Animals↗
PubMed1986

Influence of isaxonine on the target phenomenon, muscle fibre size and neuromuscular junction in the tenotomized and denervated gastrocnemius muscle of the rat.

Isaxonine is reported to accelerate the rate of peripheral nerve regeneration, stimulate axonal sprouting and promote motor and sensory function recovery. The target phenomenon in muscle fibers is the morphological expression of increased stretch activity in a diseased muscle. It can be produced in the gastrocnemius muscle of the rat by tenotomy and is inhibited by simultaneous denervation. The influence of isaxonine on this experimental model was studied. Twenty Wistar rats were submitted to bilateral section of the Achilles tendon and section of the left sciatic nerve. In ten rats, treated with isaxonine, the qualitative and quantitative changes in the gastrocnemius muscle were compared with the control group over a period of 3 weeks. No statistical differences were observed in the occurrence and inhibition of the target phenomenon, the muscle fibre size and the neuromuscular junction. Isaxonine has no direct effect on a diseased muscle with an intact nerve supply, nor in the early stages after complete denervation.

Achilles Tendon↗
PubMed1984

The use of semiautomatic morphometry in the study of normal rat gastrocnemius muscle fibers.

Based on a fixed number of EM photomicrographs, a semiautomatic image analysis is made of normal gastrocnemius muscle fibers to obtain reference values for comparison with pathologic data. Z disc, mitochondria, tubular system, and sarcoplasmic reticulum are measured. It is stated that no definite fiber type differentiation is possible based on these quantitative data. However, measurements of Z disc and mitochondria are suggestive of such a differentiation. On the other hand, all data reach a Gaussian distribution on a logarithmic scale after a 5% correction factor is introduced.

Animals↗
PubMed1983

Influence of stretch on the target phenomenon in the tenotomized and immobilized gastrocnemius muscle of the rat.

The influence of traction on the target phenomenon was analysed in the tenotomized gastrocnemius muscle of Wistar rats. Target fibres were constantly observed at the medial side of the heads of the non-immobilized and tenotomized gastrocnemius muscles used as control. In the muscles fixed in flexion, no target fibres could be detected, while in the muscles fixed in hyperextension some target fibres were seen. The latter were less numerous than those present in the non-immobilized muscles. This experiment proves the importance of stretch mechanisms in the pathogenesis of the target phenomenon.

Achilles Tendon↗
PubMed1982

Granulomatous angiitis of the nervous system: a clinicopathological study of one case.

The clinical history is presented of a 69-year-old man with a disease starting with a herpes zoster infection and an acute ascending myelopathy, and ending with an intracerebral hemorrhage. The postmortem examination revealed multiple angiitis lesions, restricted to the central nervous system. In review of the 31 previously described cases there were four other patients in whom the granulomatous angiitis of the nervous system (GANS) was associated with a herpes zoster infection. The relation between both disorders is discussed.

Aged↗
PubMed1981

Prospective neuropathologic study on the occurrence of Wernicke's encephalopathy in patients with tumours of the lymphoid-hemopoietic systems.

In this prospective neuropathologic study, Wernicke's encephalopathy appears to be the most frequent intracranial complication of treated patients with tumours of the lymphoid-hemopoietic systems. The highest incidence of this encephalopathy is found in elderly and in patients with a prolonged survival. The chronic form of Wernicke's encephalopathy is most commonly observed.

Adolescent↗
PubMed1981

Stroke pattern and topography of cerebral infarcts. A clinicopathological study.

In a series of 312 postmortem confirmed cerebral infarcts the clinical history was reviewed and the pattern of the strokes compared to the involved vascular territory. A high incidence of silent strokes was observed, and reversible neurological deficits occurred mostly in infarcts in the vertebrobasilar circulation, in particular in those in the supply area of the posterior cerebral and posterior inferior cerebellar arteries.

Brain↗
PubMed1980

Dumb-bell sarcoma of the foramen jugulare with syringomyelia. A radio-induced tumour?

The clinicopathological findings of a 50-year-old man, who developed cervicothoracic syringomyelia at the age of 25 are presented. He was given radiation therapy at the age of 33. At the age of 57 he developed a foramen jugulare syndrome on the left, caused by a low grade leiomyosarcoma. Etiologically, the most attractive hypothesis appears to be that the tumour was induced by radiation therapy administered 24 years previously.

Adult↗
PubMed1980

Cytophotometric DNA determination in human oligodendroglial tumours.

Cytophotometric DNA determination was performed on 11 surgically resected oligodendroglial tumours and on oligodendroglial cells in two normal brains. The results are compared with the histological findings, the mitotic index and the degree of clinical malignancy. In this type of glioma there is no correlation between the DNA pattern and the histological appearances and the mitotic index. It is concluded that an aneuploid DNA distribution curve corresponds to a bad prognosis, whilst a diploid DNA curve does not allow prediction of the degree of clinical malignancy.

Aneuploidy↗
PubMed1980

Pathogenesis of Binswanger chronic progressive subcortical encephalopathy.

We studied the clinicopathologic findings in four hypertensive patients with multiple leukomalacia, demyelinated lesions, and lacunar state. Only one patient had clinical evidence of dementia. The periventricular watershed infarcts were attributed to transient episodes of cardiac failure in brains with a compromised circulation in the territory of the deep perforating branches. These observations suggest that Binswanger encephalopathy does not differ from multi-infarct dementia.

Aged↗
PubMed1980

The target phenomenon in tenotomized rat gastrocnemius muscle. A comparative electrophysiological and morphological study.

In ten female rats electrophysiological recordings and subsequent histological and histochemical examinations were performed at different time intervals and in different parts of the gastrocnemius muscle, following tenotomy and following combined tenotomy and neurotomy. Repetitive motor action potentials were more easily evoked during the period and at the sites of occurrence, of target fibres in tenotomized gastrocnemius muscle with an intact nerve supply. Both phenomena, the electrophysiological as well as the morphological one, were strongly inhibited by the simultaneous neurotomy. This study suggested that the target phenomenon is a morphological expression of an increased irritability of the muscle, following tenotomy.

Achilles Tendon↗
PubMed1979

Ischemic lesions of the hippocampus and their relation to Ammon's horn sclerosis. A neuropathological study of two cases and a comparison to the vascular anatomy.

Two adult brains with small ischemic lesions in the hippocampus, due to impairment of the supply from the posterior cerebral artery, are presented. The first case corresponds to what is described in the literature as "incisural sclerosis" and shows no difference in vulnerability between the Sommer and the Spielmeyer sector. In the second case the hippocampal lesion is due to an embolic occlusion of the posterior cerebral artery and consists of selective necrosis of the subiculum, the Sommer sector and part of the endfolium of the pyramidal layer, the Spielmeyer sector remaining noninfarcted. The postmortem angiograms of 12l hippocampi of adults, as well as full term born and premature infants, show that the h1 and h2 sectors and part of the h3 sector of the hippocampus are supplied by the same "sulcus" arteries. Although there is a selective vulnerability to ischemia in some sectors of the hippocampus, which is typical for Ammon's horn sclerosis, this cannot be explained by a difference of arterial supply or by compression of arteries during the process of birth.

Blood Vessels↗