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Biomedical subjects

D Lambert

Publications and source records attributed to D Lambert.

At least 145 records · Page 8Linked to original sources

Human liver and plasma aspirin esterase.

The plasma, in addition to the liver, is a major site of hydrolysis of aspirin. Human plasma and liver aspirin esterase activities in samples from a group of patients varied over a two fold range and there was a significant correlation between individual plasma and liver activities. Human liver aspirin esterase was present in the cytosolic and microsomal fractions. Cytosolic and microsomal enzymes had different activities and apparent affinities for aspirin.

Aged↗

Cholesterol prevents the teratogenic action of AY 9944: importance of the timing of cholesterol supplementation to rats.

These studies were conducted to determine whether dietary cholesterol supplementation could prevent fetal malformations induced by the amphipathic drug AY 9944, which is well known as a cholesterol biosynthesis inhibitor, and to investigate whether the plasma maternal sterol level and the nature of the sterols found in treated Wistar rats could explain this prevention. Pituitary agenesis was the most constant element of holoprosencephaly when AY 9944 was administered on d 4 of gestation at two dosages, 50 or 75 mg/kg. The rate of malformed fetuses was dose related. A strong negative correlation was established between maternal plasma sterol levels on d 10 of gestation (day of pituitary gland formation) and the rate of fetal anomalies (r = -0.97, P less than 0.01). Supplementation of AY 9944-treated rats with cholesterol had an obvious preventive action on fetal malformations. When cholesterol was added to the diet the same day as AY 9944 treatment and maintained until d 15, the prevention of malformations was almost complete. When the supplementation was initiated later, the prevention of anomalies decreased. The nature of plasma maternal sterols shows that the cholesterol supplementation modifies significantly the ratio of cholesterol to 7-dehydrocholesterol in treated rats. Therefore, maternal plasma sterol perturbations may play a role in the teratogenic action of AY 9944.

Abnormalities, Drug-Induced↗

Controlled study of plasma exchange in pemphigus.

To determine the potential steroid sparing effect of plasma exchange in pemphigus we enrolled 40 patients in a multicenter randomized study. Eighteen patients were treated by prednisolone alone, 22 by prednisolone plus ten large-volume plasma exchanges over four weeks. All patients received oral prednisolone in the same initial dosage (0.5 mg/kg/d), which was increased weekly if needed. The number of cases controlled at each therapeutic step did not differ between the two groups. In eight cases, four in each group, the disease was not controlled by the highest therapeutic step of the protocol, with four deaths from sepsis in the plasma exchange group. The controlled cases needed similar cumulative prednisolone doses (5237 +/- 5512 mg in the plasma exchange group vs 4246 +/- 1601 mg in the control group). The evolution of serum pemphigus antibody was not different in the two groups. These findings suggest that plasma exchange in association with low steroid doses alone are not effective in the treatment of pemphigus and may even promote sepsis.

Adult↗

Lipoproteins status in professional football players after period of vacation and one month after a new intensive training program.

Plasmatic lipoproteins were evaluated in a group of 11 professional football-players after a 3-week rest, and one month later, after an intensive training (characterized by a succession of aerobic and anaerobic efforts), for engaging a new competition. At day 0, total cholesterol (TC = 4.4 +/- .04 mmol/l), triglycerides (TG = .6 +/- .04 mmol/l), and LDL-TC (2.54 +/- .18 mmol/l) were significantly decreased versus sex and age matched sedentary subjects (TC = 5.13 +/- .2 mmol/l, P less than .02; TG = .99 +/- . mmol/l, P less than .01; LDL-CT = 3.26 +/- .2 mmol/l, P less than .02). HDL-TC was increased (1.50 +/- .06 vs 1.30 +/- .05 mmol/l, P less than .05). The apoprotein A1 (apoA1) was higher in football-players (1.5 +/- .06 vs 1.16 g/l, P less than .001), while the apoprotein B (apoB) was lower (.6 +/- .03 vs .88 +/- .04 g/l, P less than .001). Even after 3 weeks of rest, the football-players lipoproteins were still identical to aerobic elite-athletes. At day +30, after a daily training involving 2 anaerobic sequences, the maximal aerobic capacity was increased by 21%, without any change in nutritional, plasmatic and hepatic status. Weight was diminished (-0.8 kg, P less than 0.05). TC (4.14 +/- .2 mmol/l), TG less than .64 +/- .08 mmol/l), LDL-TC (3.37 +/- .17 mmol/l), apo B (.64 +/- .05 g/l) were unchanged. HDL-CT fell to controls values while apoA1 increased (1.66 +/- .06 mmol/l, P less than .001). Thus, HDL-CT/apoA1 ratio (indicating the TC content of HDL) was decreased, whereas apoB/apoA1 ratio was unchanged. The decrease of TC content of HDL was not related to dietary change nor to weight decrease. As TG were stable, the lipoprotein lipase activity could not be modified.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Photosensitization after intramuscular injections of hematoporphyrin. 3 cases].

Haematoporphyrin is a synthetic porphyrin the photosensitizing properties of which are used for the detection and treatment of some neoplasias. Three cases of phototoxicity from Hemedonine, an "anti-asthenia" drug composed of pure haematoporphyrin, are reported. Following exposure to the sun, painful urticarial plaques developed at the sites of intramuscular injections, and spread to the lumbar and abdominal regions, leaving a brownish pigmentation which persisted for years. Photobiological exploration was performed in one of these patients, demonstrating photosensitivity to Hemedonine in vivo and showing that long UVA rays were essentially responsible for the lesions. Histological examination elicited the initial vascular changes of a phototoxic reaction and suggested a new mechanism of photosensitization: "photo-induced immune vasculitis". The phototoxic effects of haematoporphyrin are primarily due to the destruction of intracellular organelles consecutive to oxidative denaturation of membrane systems. The initial phase of the phototoxic reaction might consist of complement activation and degranulation of dermal mast cells.

Adult↗

Ethoxyresorufin O-deethylation by human liver microsomes.

As a substrate for human liver microsomes, ethoxyresorufin appears to be metabolised by a group of cytochrome P450 isoenzymes which are inducible by cigarette smoking. Kinetic studies in microsomes from four human livers indicate that only one enzyme component is involved over the full substrate range. Ethoxyresorufin O-deethylation activity at both high and low substrate concentrations correlated with the high affinity component of ethoxycoumarin O-deethylation and of diphenyloxazole metabolism.

Adult↗

Long-term effect of bran ingestion on lipid metabolism in healthy man.

The long-term effect of the addition of 20 g wheat bran to the diet is studied over 7 weeks in 4 healthy subjects. No change is found in plasma cholesterol and triacylglycerol. In this experimental design, we find no modification in the plasma levels of the various lipoproteins, except for VLDL cholesterol, which remains significantly lower after 7 weeks of wheat bran ingestion.

Adult↗