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Biomedical subjects

M Laurent

Publications and source records attributed to M Laurent.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Modification of human platelet behaviour in diabetes.

Among the different factors which could be responsible for the retinal vascular disturbances in diabetic retinopathy, we have investigated platelet populations, sialic acid content of platelets and collagen-induced platelet aggregation. The following results were obtained: a) there was no modification of platelet population distribution except for population A; b) there was a modification of collagen-induced platelet aggregation; the lag time was increased in diabetics.

Adult↗
PubMedDate not supplied

Evolution of a trypanosome surface antigen gene repertoire linked to non-duplicative gene activation.

African trypanosomes activate, one at a time, a large set of genes coding for different variant-specific surface antigens (VSAs). These genes have been classed into two groups. In the first group a permanently silent basic gene copy is duplicated and the expression-linked copy (ELC) transposed to an expression site located at a chromosome end. The process is a gene conversion which changes a variable stretch of the preceding ELC. Genes belonging to the second group do not give rise to an additional copy when expressed by a still unknown mechanism. We report here that the gene for antigenic type AnTat 1.6 is located in a telomeric DNA region and is expressed without being duplicated. In clone AnTat 1.6 and the ensuing ones, the ELC of the preceding VSA (AnTat 1.3) is conserved, but in a inactive conformation. Moreover, the AnTat 1.6 gene is lost from the genome of the AnTat 1.6-derived variants, in which the duplication-linked mechanism of gene activation occurs: the gene appears to be replaced by the incoming ELC. These observations show that a trypanosome surface antigen repertoire may evolve by loss and gain of VSA genes, depending on the alternation of the different recombinational mechanism involved in antigenic variation.

Antigens, Surface↗
PubMedDate not supplied

[Myasthenia in the aged: a case with unusually late onset].

BACKGROUND: Myasthenia is an uncommon autoimmune condition that can occur at any age. Peak frequency is seen around the age of 65 years. We report a case with a particularly late onset and discuss the particular conditions of myasthenia in the elderly subject. CASE REPORT: A 97-year-old patient was hospitalized for dysphonia and dysphagia associated with exercise-induced dyspnea. The general picture suggested generalized myasthenia confirmed by the electromyography exploration and a positive anticholinesterase test. Treatment with acetylcholinesterase inhibitor was effective although cure was incomplete. Further improvement was obtained with immunosuppressor therapy using azathioprine. DISCUSSION: The clinical presentation of very late onset myasthenia differs little from that in younger subjects excepting the very high frequency of brain stem involvement in the initial presentation. Diagnosis may however be more difficult as other conditions are more easily taken to be the causal element. Thus, for the elderly patient, the real problem is to envisage the diagnosis of myasthenia. Positive diagnosis is based on the same criteria as in younger subjects. Clinicians should be aware of the possibility of myasthenia in the geriatric population as specific treatment can improve functional prognosis with satisfactory efficacy.

Age Factors↗
PubMedDate not supplied

[Acute pericarditis].

Explore the source record for details and available documents.

Acute Disease↗
PubMedDate not supplied

[Cytology of various rare benign tumors of the breast].

The authors describe the cytological appearances of three rare benign mammary tumors (granular cell myoblastoma, sebaceous cyst and fibrous histiocytoma), and warn the clinician against over-optimism when presented with a benign cytologic diagnosis. In fact, the proportion of cases in which carcinoma is confused with a benign tumour varies from 3 to 5% according to statistics. They analyse the various causes responsible for the "false benign" diagnosis. The author's opinion is that one can only arrive at the cytological diagnosis of benignity as part of a group of investigations. Final diagnosis must depend upon a histological examination.

Breast Neoplasms↗
PubMedDate not supplied

[Focus on post and cores].

Inspite of the new technics using composite resin, cast dowel and core is still used to replace lost coronal structure of endodontically treated teeth. Before the core preparation, an X-ray is essential. The metal used for the post and core must be the same as the one used later for the following full crown. Preparation methods must be well established. Acrylic resin or silicone may be used as impression technics.

Crowns↗