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Biomedical subjects

P Lafargue

Publications and source records attributed to P Lafargue.

At least 19 recordsLinked to original sources
PubMed2000

In situ examination of tyrosine hydroxylase activity in the rat locus coeruleus using (3',5')-[(3)H(2)]-alpha-fluoromethyl-tyrosine as substrate of the enzyme.

Tyrosine hydroxylase (TH) activity can be modified by changes in the specific activity of the enzyme (SA(TH)) or in the levels of active enzyme. We developed a methodology making it possible to measure with excellent anatomical resolution TH enzymatic activity and TH protein quantity by quantitative autoradiography and immunoautoradiography, respectively, from adjacent sections taken at serial intervals along the longitudinal extent of a same brain. SA(TH) was estimated by the slope of linear regressions established between TH activity and TH quantity measured at each anatomical plane. To evaluate TH activity, we used (3',5')-[(3)H(2)]-(D, L)-alpha-fluoromethyl-tyrosine [(3)H(2)]-MFMT, which is transformed by TH to [(3)H]-MFM-dopa, a potent and irreversible substrate for aromatic amino acid decarboxylase. We found that the SA(TH) in the cell body area of the LC (PKA) was 48% lower than that evaluated in the surrounding pericoerulean neuropil (PCN). In the PCN, 22% only of TH level exhibited a level of enzymatic activity above threshold. We also examined how SA(TH) was distributed in the LC 15 min and 3 days after RU 24722 treatment, a potent phasic and tonic activator of TH enzyme in noradrenergic neurons. Two distinct mechanisms have been observed: the short-term effect was due to an increase in the SA(TH) in the PKA only, while the long-term effect was mainly caused by an increase in the number of active TH proteins in the PCN. These results suggest that the fine regulation of TH activity which occurs in the different compartments of LC neurons may be critical in the functions involving the LC.

Animals↗
PubMed1995

[Study of urinary excretion of codeine and morphine after oral ingestion of codeine].

Results of an investigation on the urinary excretion of codeine and morphine after oral ingestion of 1 mg.kg-1 b.w codeine are reported. The investigation run on seven clinically healthy subjects showed: low digestive absorption of codeine (# 20%); rapid biotransformation of codeine into morphine (first urines excreted after absorption); rapid disappearance of codeine from urines (#30 hrs); persistence of morphine alone (#68 hrs); rapid evolution of the codeine/morphine ratio (inversion of the ratio after #18 hrs); total elimination of morphine which can be greater than for codeine; very different half-life periods for codeine and morphine (5.1 and 13.6 hrs); no other codeine metabolites (nor-codeine and nor-morphine); very high individual variations; one subject with low activity of cytochrome P 450 dbl/buFL. Finally, in an epidemiological survey of drug addict behaviors and detection of drug addiction, it seems very difficult, may be even illusory and hazardous, to try and justify morphine found in urines (morphine, heroin, codeine, codethyline, pholcodine...) except in the very legitimate case where the ratio of urine concentrations of codeine and morphine is greater than one.

Administration, Oral↗
PubMed1995

[Revealing hair].

Hair testing is an effective method for identifying chronic drug abusers. The procedure involves a decontamination step, acid hydrolysis in presence of deuterated internal standards, liquid-liquid extraction and analysis by gas chromatography coupled to mass spectrometry. Hair analysis has a wide window of detection ranging from months to years and provides informations concerning the severity and pattern of an individual's drug use.

Female↗
PubMed1994

Synthesis of [3',5'-3H2]-alpha-fluoromethyl-tyrosine as a radioactive specific label of rat brain tyrosine hydroxylase.

The [3',5']-ditritio-alpha-fluoromethyl-tyrosine 4 (specific activity 15.0 Ci/mmol) has been synthesized and used as a radioactive probe for rat neuronal tyrosine hydroxylase (TH). The route of synthesis for the preparation of 3 and 4 allowed us to not only introduce a fluorine atom into 3/4 using an inorganic source of fluorine (CsF), but also to take advantage of the high-yielding cyclization of (alpha,beta)-acetamido alcohols mediated by diethylaminosulfur trifluoride (DAST) to give the corresponding oxazolines. The distribution and metabolism of 4 have been studied in control conditions within the rat locus caeruleus (LC). Intracisternal injection of 20 microCi of 4 was followed by a rapid disappearance of 4 (t1/2 = 1.5 h) and by a specific accumulation of radioactivity into the LC anatomical limits. This was investigated each 140 microns along the caudo-rostral axis of the noradrenergic nucleus. In each anatomical interval, its distribution correlated nicely with already described caudo-rostral distribution of TH in noradrenergic cells. Thus, 4 may provide a reliable measure of TH activity in such catecholamine structures.

Animals↗
PubMed1990

Zinc metabolism in the athlete: influence of training, nutrition and other factors.

Serum zinc was measured four times (October, January, March and May) in six young male athletes during a nine-month sporting season in relation to eleven other parameters. A significant decrease in serum zinc was observed after five months of intensive training (all values remaining in the normal range). This cannot be explained by changes in dietary habits, plasma protein concentrations, hormonal changes nor by the existence of minor infectious or inflammatory pathologies. The dietary intakes seemed adequate. These results support the hypothesis that zinc status may be slightly altered in the high-level athlete.

Adult↗
PubMed1989

Influence of polyunsaturated fatty acid diet on the hemorrheological response to physical exercise in hypoxia.

Several studies have shown that hemorrheological parameters are modified by physical exercise and exposure to altitude hypoxia. These changes result in a decrease in red cell deformability (RCD). Similarly, it has been shown that a daily dietary fish oil supplement increases RCD. The purpose of this study was to evaluate the influence of fish oil diet on RCD after exercise. Fourteen male subjects (19-38 years old) were divided into two groups. The first group ate a "standard diet" rich in saturated lipids; the second group received a daily amount of 6 g of MaxEPA fish oil for 6 weeks. Before the 6 weeks of experimental nutrition, and just after this period, both groups were submitted to two physical exercises of 1 h cycling at 70% of their VO2max. One test was performed at sea level, the other at a simulated altitude of 3000 m in a hypobaric chamber. Blood samples were drawn before and after exercise and used to evaluate: (1) RCD by filtration on polycarbonate membrane, (2) plasma viscosity, and (3) erythrocyte phospholipid composition. Energy charge of red cell was evaluated by ATP/AMP/ADP and two to three DPB assays. Gas liquid chromatography indicated an increase in n-3 PUFA membrane erythrocyte composition. In the control group, RCD decreased by an average of 53% after exercise under hypoxic conditions and was unchanged after the same exercise at sea level. MaxEPA diet suppresses the decrease in RCD observed after hypoxic exercise. These results indicate a decrease in RCD under the combined effects of exercise and hypoxia, which is prevented by 6 weeks of fish oil supplement.

Adenosine Diphosphate↗
PubMed1988

[Plasma viscosity and erythrocyte filterability in borderline hypertension].

Hemorheological constants (plasma viscosimetry and erythrocyte filtrability index) were studied in 153 male subjects aged 19 to 23. Borderline hypertension defined by clinical criteria was found in 61 of these patients. Whilst there was no notable modification in plasma viscosity, by contrast there was a significant link between erythrometry and systolic and diastolic blood pressure. Erythrocyte deformability was all the more marked as blood pressure rose. These results would contrast with findings in the literature in cases of definite hypertension. The borderline nature of hypertension and the youth of the population was such that it could be considered that barometric factors had not yet influenced erythrocyte filtrability. The following hypothesis is therefore attractive: initially the red cell adapts itself to any possible increase in peripheral resistance. As the years go by its deformability is lessened by adverse changes affecting its membrane cytoskeleton.

Age Factors↗
PubMed1977

Creatine kinase activity in suicide by burning.

In the course of a systematic study of serum enzymes activities from muscular tissues, applied to fifty six burnt patients taken at random, the authors have observed a significant and isolated raised of serum CPK in six burnt people when they were admitted to hospital. There were no known causes of raised CPK essentially due to muscular isozyme. The only common point between those six persons is that they all attempted to commit suicide by burning.

Burns↗
PubMed1976

[Evolution of serum copper and zinc levels in burn patients (author's transl)].

The study of copper and zinc in 35 patients, over periods of up to 21 days following thermal injury, is marked by an important and early fall in serum copper and zinc levels. The maximum intensity of the biological disturbance appears about two days after the injury. Reversion to near normal values coincides with recovery from the large part of the lesions. The comparison of the evolution of serum levels does not permit any definite relationship to be established between copper and zinc metabolism.

Burns↗
PubMed1975

[Value of the determination of gamma glutamyl transpeptidase in the detection of hepatic metastases of bronch-pulmonary cancers].

The authors have dosed gamma glutamyl transpeptidase in 42 patients with primary bronchopulmonary cancer, of whom 14 had liver metastases. In these 14 patients the level of gamma glutamyl transpeptidase was always high, except in 1 case; while in the remaining lot, a moderate and mostly belated increase was noticed in only 32 percent of cases. The dosing of gamma glutamyl transpeptidase present some interest in the detection of liver metastases in primary bronchopulmonary cancers, specially when coupled with the dosing of alcaline phosphatase. Interpretation of results should take into account the existence of an associated liver-gall bladder involvement and of a recent surgical operation; both factors being capable of raising the level of gamma glutamyl transpeptidase.

Adenocarcinoma↗