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Biomedical subjects

C Duyckaerts

Publications and source records attributed to C Duyckaerts.

222 records · Page 13Linked to original sources
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Fibre disorganization in the neocortex of patients with senile dementia of the Alzheimer type.

The loss of neurons, which is thought to occur during senile dementia of the Alzheimer type, could alter the fibre organization of the neocortex. In the present study, the density and course of the fibres were measured in histological sections in 14 cases: all were women over 75 years of age who had been living in a long-stay hospital and had been prospectively assessed by the test score of Blessed et al. (1968). Their intellectual status ranged from nearly normal to severely demented. Samples from the supramarginal and prefrontal gyri were studied after Bodian's impregnation. The course of the fibres in 3-dimensional space was determined by two angles: (a) the angle which characterized their orientation in the plane of section and discriminated between horizontal (tangential), vertical (radial) and oblique fibres and (b) the angle of section with which the fibres were cut. The total density of fibres correlated neither with the test score nor with the density of neurofibrillary tangles or senile plaques. The percentage of obliquely orientated fibres and of fibres with a high sectioning angle increased in the course of the disease. This increase was mainly at the expense of the horizontal fibres in the supramarginal gyrus and could be explained by the presence of a great number of small, tortuous and abnormally orientated fibres (kinked fibres) in the most severely affected cases. The methodology employed in this study could be useful in the investigation of fibre architecture in other diseases involving the cerebral cortex.

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Comparison of seven staining methods for senile plaques and neurofibrillary tangles in a prospective series of 15 elderly patients.

Samples of brain from 15 prospectively tested women over 75 years of age, living in the same institution and with a Blessed test score between 0 and 28 were studied to evaluate seven different staining techniques for counting senile plaques and neurofibrillary tangles. The methods included Bielschowsky (modified by Yamamoto & Hirano, 1986), Cross, Gallyas, Naoumenko-Feigin, silver methenamine, Bodian coupled with luxol fast blue, and thioflavine S; these techniques were performed on contiguous slides of the first temporal gyrus (Brodmann's area 22). The cost, difficulty and variability of the methods were evaluated. Modified Bielschowsky method revealed both amyloid and neurites. Cross, Bodian and Gallyas stained neurites preferentially and were more sensitive for neurofibrillary tangles than for senile plaques. Silver methenamine revealed amyloid in much the same way as thioflavine S. The highest count of senile plaques and neurofibrillary tangles was obtained with the modified Bielschowsky method. Best correlations between density of senile plaques and Blessed test score were obtained with modified Bielschowsky impregnation, silver methenamine, and Bodian and those for neurofibrillary tangles, with modified Bielschowsky, Naoumenko-Feigin, and Gallyas methods. Naoumenko-Feigin impregnation, even if fitted to the linear model, revealed very few changes (four times less than modified Bielschowsky) and appeared to be insensitive. All the techniques except Naoumenko-Feigin, were equally able to distinguish two groups of cases, i.e. those affected by Alzheimer's disease and those not affected. A multiple regression analysis indicated that the statistical relationship between the density of changes, evaluated after the modified Bielschowsky method, and the Blessed test score could not be improved by the additional use of other staining techniques. These data have direct implications for the evaluation of diagnostic criteria in Alzheimer's dementia. In this study, modified Bielschowsky impregnation was found to give the most complete picture of the lesions and, as such, could be considered a reference method. This technique is, however, expensive and difficult to perform. It stains a large number of normal structures and the recognition of the lesions is more subjective than with other selective stains. It is therefore difficult to recommend this technique for routine use. Other techniques alone, or in combination, can be recommended but the diagnostic criteria should be adapted for each of them.

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PubMedDate not supplied

Age and cerebral infarction: a postmortem study of 77 cases of cerebral infarcts in the middle cerebral artery territory.

Adverse effect of age on ischemic stroke short-term mortality was reported in some studies and attributed either to more frequent extracerebral causes of death or to an increased severity of ischemia in the aged brain. Relationship between age, size of infarcts, and causes of death were studied in 77 consecutive patients who died from infarction in the middle cerebral artery territory. Area of infarcts was assessed by planimetry, and results were expressed as an index of infarcted area. No significant relationship was found between age and the size of infarcts, the cause of death, or the interval from stroke to death. These results do not support the hypothesis of an increased severity of ischemia in the aged brain.

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PubMedDate not supplied

[Morphometric and radioautographic study of neuronal loss and gliosis in sclerosis of the hippocampus associated with temporal lobe epilepsy].

Hippocampal sclerosis is a complex combination of neuronal and glial changes. It is frequently associated with temporal lobe epilepsy. Six hippocampal specimen were obtained from patients operated on for intractable mesial temporal lobe epilepsy. Comparisons were made with six autopsy controls. The neuronal and glial cells populations were studied by morphometric quantitative analysis. The glial cell types were identified by immunohistochemistry procedures. Distribution of the central (neuronal location) and the peripheral (glial location) benzodiazepine (BZ) binding sites was studied by quantitative autoradiography using [3H]-flumazénil and [3H]-PK11195 as respective ligands. Neuronal death and glial proliferation with the usual HS pattern were confirmed in all cases. Microglial cells, labelled with KP1 antibody (resident component) and with HLA-DR alpha (reactive component) were qualitatively similar in patients and controls. Particular radial organization of numerous, long and thin astrocytic processes, as labelled with GFAP antibody, was observed in the molecular layer of the dentate gyrus in 5 cases. These fibrillary processes were intermingled with the granule cells, which were markedly dispersed in 4 of the cases. In comparison with control group, all the epileptic cases had significant selective decreased central-type and increased peripheral-type BZ receptor. These results were respectively correlated with neuronal loss and glial proliferation. Morphologic results suggest that a specific configuration of astrocytic cell processes may be associated with some of the neuronal changes of human HS. Such aspect has not been reported in the astroglial growth observed in animal models of limbic epilepsy. The lack of reactive microglia suggested the absence of recent cell death.(ABSTRACT TRUNCATED AT 250 WORDS)

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