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Biomedical subjects

J de Keyser

Publications and source records attributed to J de Keyser.

9 recordsLinked to original sources
PubMed1994

[3H]Clozapine is not a suitable radioligand for the labelling of D4 dopamine receptors in postmortem human brain.

Clozapine displays nanomolar affinity for cloned human D4-type dopamine receptors expressed in tissue culture cells. Therefore, [3H]clozapine has been introduced as a radioligand for the labelling of the D4 dopamine receptors. We found that, in membranes of postmortem human striatum, amygdala, frontal cortex and substantia nigra, neither dopamine nor the dopamine agonist apomorphine displaced the binding of [3H]clozapine (5-20 nM). [3H]Clozapine competition curves with clozapine and loxapine revealed the presence of two binding sites. The high-affinity site was displaced by atropine and pirenzepine with nanomolar affinity. The low-affinity site did not correspond to a serotonin, adrenergic, gamma-amino butyric acid, N-methyl-D-aspartate, benzodiazepine, histamine, sigma, imidazoline receptor-binding site, or catecholamine uptake site. Our results suggest that [3H]clozapine in postmortem human brain binds to M1-type muscarinic cholinergic receptors and to a low-affinity binding site but is not a suitable radioligand for investigating the D4 dopamine receptors.

Aged↗
PubMed1991

Central-nervous-system demyelination after immunisation with recombinant hepatitis B vaccine.

2 patients had neurological symptoms and signs, with evidence of central-nervous-system demyelination, 6 weeks after administration of recombinant hepatitis B vaccine. 1 had known multiple sclerosis but the other had no history of neurological disease; both had HLA haplotypes DR2 and B7, which are associated with multiple sclerosis. A causal link between vaccination and demyelination cannot be established from these 2 case-reports, but the time interval would fit a proposed immunological mechanism.

Adult↗
PubMed1990

The effect of aging on the D1 dopamine receptors in human frontal cortex.

Dopaminergic pathways to the cerebral cortex may be involved in cognitive function. We examined the effect of aging on the D1 dopamine receptors, and their high-agonist affinity (RH) sites, in postmortem human frontal cortex (n = 32; age range, 19-88 years). With aging, there was a significant decrease in the densities of the D1 dopamine receptors, and their RH sites, in human frontal cortex. The age-related reduction of cortical dopaminergic neurotransmission might contribute to the decline in cognitive abilities of elderly persons.

Adult↗
PubMed1986

Brain stem infarction as a complication of giant-cell arteritis.

Two cases of brain stem infarction as an early and fatal complication of giant-cell arteritis are reported. These complications occurred despite adequate treatment with corticosteroids. The findings at autopsy are compared with those of the literature. The possible pathogenetic mechanisms of vertebro basilar occlusion and the therapeutical implications are discussed.

Aged↗
PubMed1985

Enophthalmos as a rare manifestation of metastatic orbital involvement.

Two cases in which orbital metastasis produced enophthalmos, instead of the usual exophthalmos, are reported. Only fourteen other cases have been described previously and they are reviewed. At time of diagnosis of the enophthalmos, meningeal carcinomatosis coexisted in the first case and probably also in the second case. This association can lead to diagnostic errors with either the orbital metastasis or the meningeal carcinomatosis being missed. In addition, as in our second case, the enophthalmos can be the initial manifestation of cancer.

Adult↗
PubMed1984

Lower motor neuron disease in a patient with Hodgkin's disease treated with radiotherapy.

A case of lower motor neuron disease after extended field irradiation for cervical stage IA nodular sclerosing Hodgkin's disease is reported. Recurrence of Hodgkin's disease is excluded and other diagnostic possibilities are discussed. We compared this case with twenty-four similar cases reported in the literature after irradiation of the spinal cord for Hodgkin's disease or other neoplasms. Special features included the relatively advanced age of the patient, the long latency period, a premonitory CK-rise and reversibility. The entity is considered to be a very rare and relatively benign complication of spinal cord irradiation important to recognize as an entity in order to avoid extensive reevaluation.

Electromyography↗