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Biomedical subjects

J Buret

Publications and source records attributed to J Buret.

At least 19 recordsLinked to original sources
PubMed1989

Postoperative changes in lipid profile: their relations with inflammatory markers and endocrine mediators.

Postoperative changes in plasma lipid profile have been studied in six patients undergoing aortobifemoral bypass. The second day after surgery, significant changes were: decreased levels of high density lipoprotein (HDL) cholesterol (by 55%), non HDL cholesterol (by 60%) phospholipid (by 50%), pre-beta-lipoprotein (by 70%), beta-lipoprotein (by 50%), apolipoprotein A1 (by 60%) and apolipoprotein B (by 55%). The magnitude of these changes correlated positively with serum levels of transferrin and negatively with serum levels of C-reactive protein. Triglyceride levels also showed a significant decrease (by 60%) while free fatty acids increased by 70%. Changes in triglyceride levels were not correlated with serum transferrin and C-reactive protein but showed a significant negative correlation with insulin levels. Our results suggest that both inflammatory and endocrine mediators are likely implicated in the postoperative changes in lipid profile.

Biomarkers↗
PubMed1987

In-vivo studies on Haemaccel-fibronectin interaction in man.

An enzyme-linked immunoassay has been recently set up for direct measurement of the binding capacity of plasma fibronectin to gelatin. This binding capacity could be completely inhibited in vitro by an eight-fold excess of gelatin, of Haemaccel, but not of Geloplasma. On the contrary, the levels of immunoreactive fibronectin measured by laser nephelometry did not change, in presence of 10 to 1000 micrograms ml-1 of gelatin, of Haemaccel or of Geloplasma. When infused into normal volunteers, Haemaccel provoked a strong and immediate inhibition of the plasma fibronectin binding capacity to gelatin. This inhibition was dose-dependent and maximal after infusion of 500 ml of Haemaccel. Twenty-four hours after this infusion, there was a progressive recovery of the gelatin-binding capacity, which was almost completely achieved 96 h later. The formation of complexes between Haemaccel and fibronectin was demonstrated by gel filtration chromatography and by affinity chromatography. Immunoreactive plasma fibronectin levels remained unchanged up to 24 h after infusion of 500 ml of Haemaccel. A transient decline to 50% of its initial value then occurred the second day after the infusion. Therefore, a delay existed between the formation of fibronectin-Haemaccel complexes and their elimination from the bloodstream. This delay decreased when smaller volumes of Haemaccel were infused, which strongly suggests that plasma fibronectin is cleared by means of Haemaccel and does not seem to play a role of opsonin in these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, Affinity↗
PubMed1986

[Significance of lactate dehydrogenases in pleural effusions].

In order to determine the exact significance and origin of lactate dehydrogenases (LDH) present in pleural effusions, LDH and their enzymes were assayed in the serum and pleural fluid of 60 patients with wet pleurisy and in the main blood cells (haematocytes, polymorphonuclears mononuclears) found in pleural fluids. Our results showed that: a pleural fluid/serum LDH ratio above 0.7 indicates that the fluid is an exudate; however, in about 10% of inflammatory pleural effusions due to infection or cancer this ratio is comprised between 0.5 and 0.7; the enzyme profile of transudates only differs from that of normal serum by a slight increase in isoLDH 4 and 5; in exudates this profile is the reverse of the normal serum profile, with a decrease in isoLDH 1 and 2 and an increase in isoLDH 4 and 5; the enzyme profile provides little information on the origin of exudates, although a more than 30% rise in isoLDH 2 is in favour of a malignancy (mesothelioma excluded); polymorphonuclears contain more isoLDH 4 and 5 than mononuclears; activation of mononucleate cells is attended by a significant increase in intracellular isoLDH 4 and 5; the presence of red blood cells and/or haemolysis in an exudate cannot account for its high isoLDH 4 and isoLDH 5 content; the high content seems to be due, at least partly, to release of these enzymes by the polymorphonuclears and/or mononucleate cells involved in pleural inflammation.

Adult↗
PubMed1985

Serum lipid and lipoprotein changes induced by new oral contraceptives containing ethinylestradiol plus levonorgestrel or desogestrel.

Changes in serum lipid and lipoprotein levels were evaluated in a randomized prospective study conducted in matched healthy young women before and after 6 months' use of three oral contraceptives (OCs): Trigynon (preparation A, n = 13), a triphasic OC containing low doses of ethinylestradiol (EE) and levonorgestrel (LNG); Marvelon (preparation B, n = 14), a monophasic OC containing low doses of EE + Desogestrel (DOG, a new progestogen derived from LNG); and Ovidol (preparation C, n = 11), a sequential OC containing higher doses (50 micrograms) of EE + DOG. After 6 months of use, total triglyceride levels were non-significantly increased by preparations A (+ 29% from basal values) and B (+21%), and very significantly increased by preparation C (+90%). Total cholesterol and phospholipids were unchanged by preparations A and B, whereas phospholipids were significantly increased by preparation C. However, HDL-cholesterol, LDL-cholesterol and their epidemiologically important ratios (HDL-chol:total-chol; LDL-chol:HDL-chol) were kept unchanged by all preparations tested. Apolipoprotein A-1 (Apo A-1) was slightly but significantly increased by all three preparations whereas apolipoprotein B (Apo B) was significantly decreased by preparation B. All ratios Apo A-1:Apo B were accordingly ("favorably") increased, especially during treatment with preparation B. In conclusion, the triphasic OC containing low doses of LNG does not induce obvious, clinically significant, alterations of lipid metabolism, and it is also the case for the low-dose monophasic combination of EE + DOG. The higher-dose sequential preparation of EE + DOG behaves as a more estrogenic compound, increasing total triglyceride concentrations above the normal range.

Adult↗
PubMed1982

A one-step determination of serum 5'-nucleotidase using a centrifugal analyzer.

We describe a one-step kinetic method for the determination of 5'-nucleotidase (EC 3.1.3.5). Inosine is formed by the hydrolysis of inosine 5'-monophosphate which is catalyzed by seric 5'-nucleotidase, and then is converted to hypoxanthine by nucleoside phosphorylase. Two moles of hydrogen peroxide are formed for each mole of hypoxanthine oxidized to urate by xanthine oxidase. The rate formation of hydrogen peroxide is monitored at 510 nm using the oxidation of the chromogenic system 3,5-dichloro-2-hydroxybenzenesulfonic acid/4-aminophenazone in the presence of peroxidase. beta-Glycerophosphate inhibits the unspecific cleavage of the substrate by alkaline phosphatases. Inorganic phosphate is added to improve the reagent stability, and ferrocyanide to reduce bilirubin interference. Automation of the technique requiring 20 microliter of serum on a centrifugal analyzer is also described.

5'-Nucleotidase↗
PubMed1979

Concentrating capacity of the kidney and nitrogen partition in the urine in Perodicticus potto (Prosimii, Lorisidae, Lorisinae).

The concentrating ability of the kidney in Perodicticus potto was investigated. As the relation between this capacity and the thickness of the medulla has been stressed by Schmidt-Nielsen & O'Dell, the size of the various layers in the kidney was measured. Based on our observation that the potto may excrete uric acid in fairly high concentrations, the partition of nitrogen in the urine was also explored.

Animals↗