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Biomedical subjects

L Molle

Publications and source records attributed to L Molle.

At least 19 recordsLinked to original sources

Selenium status in relation to clinical variables and corticosteroid treatment in rheumatoid arthritis.

Plasma selenium levels, erythrocyte selenium levels and activity of the selenoenzyme glutathione peroxidase in erythrocytes were determined in patients with rheumatoid arthritis (RA) and acute inflammatory arthritis. Results were compared with those from age and sex matched controls. These variables were not statistically different from controls in patients with inflammatory arthritis and in patients with RA not treated with corticosteroids. No correlation was found in RA between plasma selenium biological variables of inflammation and most clinical indices of disease severity. Therefore, acute or chronic inflammation was not the main factor that accounted for low plasma selenium levels in RA. Corticosteroid treatment, particularly at high doses (20-60 mg prednisolone/day), was significantly related to the depressed plasma selenium levels of some patients with RA. The mechanisms underlying this modification remain poorly understood.

Acute Disease

Selenium deficiency.

Selenium is undoubtedly an essential trace element: its involvement in GPx structure, the presence of deleterious effects of selenium deficiency in animals, and the recognition of deficiency states in man attest to its importance. However, if the consequences of selenium deficiency in man are now widely recognized, the mechanisms underlying these conditions are poorly understood. The definition of the exact role of selenium in human homeostasis has been hampered by the lack of a sensitive parameter, usable in routine investigation, to assess selenium status. Measurements of plasma and urinary levels, although useful in clinical practice, are inadequate indicators. The only true evidence of selenium deficiency lies in a positive response to selenium therapy. Deficiency states have been demonstrated for inhabitants of regions where selenium supply is limited, in protein-energy malnutrition, and in patients maintained on total parenteral nutrition without selenium supplementation. The benefit of selenium supplementation, together with other antioxidant drugs, in non-deficient subjects is still a matter of debate; its protective effect in neoplastic, cardiovascular and neurological degenerative diseases is not yet proven.

Animals

Degradation study of catecholamines, indole amines and some of their metabolites in different extraction media by chromatography and electrochemical detection.

Optimal conditions for the extraction from brain tissue and the simultaneous quantification of catechol and indole derivatives were determined after a systematic degradation study in water and perchloric acid. The roles of three parameters, namely temperature, presence of antioxidant agents, and time, were considered. Adrenaline, noradrenaline, dopamine, homovanillic acid, 5-hydroxytryptophan, 5-hydroxyindole acetic acid, serotonin, and epinephrine were separated by HPLC and detected electrochemically. The results indicated a great instability of the indole derivatives at an ambient temperature, in an acid medium, and in the absence of a protective agent. Therefore, when perchloric acid has to be used for deproteinization, the lowest concentration (0.1 M) is preferable. The samples have to be kept on ice, in darkness, and protected by ascorbic acid and sodium ethylenediamine tetracetate.

Ascorbic Acid

Selenium, zinc and copper in Down's syndrome (trisomy 21): blood levels and relations with glutathione peroxidase and superoxide dismutase.

Increased superoxide dismutase and glutathione peroxidase activities have been reported in erythrocytes of subjects with Down's syndrome. Since these enzymes contain specific trace-elements as essential components, we have determined copper, zinc and selenium levels in plasma and erythrocytes of 29 trisomy 21 patients compared with 32 age-matched controls and examined the relations with the enzymes' activities. In plasma, mean zinc and copper levels were normal, but selenium was found to be significantly decreased (p less than 0.001). In red cells, the increase of activity of the selenoenzyme glutathione peroxidase (p less than 0.001) was not accompanied by an increase of erythrocyte selenium, but a significant correlation was found between these two values (r = 0.67, p less than 0.001). Zinc and copper levels in red cells were significantly higher than normal (p less than 0.001) and this increase could be partly explained by the increased activity of the copper and zinc containing enzyme superoxide dismutase (p less than 0.001). Low plasma selenium and the strong relation between erythrocyte selenium and glutathione peroxidase activity we found in Down's syndrome should stimulate interest in a more detailed investigation of selenium status and metabolism of these patients.

Adolescent

Binding study of benzamides to serum albumins by fluorescence probe technique.

The interaction between human and bovine serum albumins (HSA and BSA) were studied with two derivatives of benzamide, metoclopramide (Primpéran) and sultopride (Barnétil). It was possible to evaluate association constants (K ass.) characterising this interaction by fluorescence probe technique inspite of the very low binding tendency, which can be correlated to pharmacokinetic properties of these drugs.

Animals

[Drug abuse].

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Drug Therapy