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Biomedical subjects

M C Patricot

Publications and source records attributed to M C Patricot.

At least 19 recordsLinked to original sources
PubMed2002

[Relation between physical activity, muscle function and IGF-1, testosterone and DHEAS concentrations in the elderly].

OBJECTIVE: Lower amounts of circulating anabolic hormones are thought to accelerate the age related decline in muscle mass and function. Replacement therapies are promising interventions but there are problems with these therapies. Thus alternative strategies should be developed. The age related changes in hormonal status may be probably influenced by exercise. The purpose of this study was: a) to confirm with other methods, more adapted for elderly people, the results of a previous study that has shown relationship between physical activity (PA) and quadriceps muscle function with dehydroepiandrosterone sulphate (DHEAS), insulin like growth factor-1 (IGF-1). Quadriceps muscle power (Pmax) is measured in this new work with a recently developed leg extensor machine and, b) to complete the results of the first study examining simultaneously the relationship between PA, Pmax and cardiorespiratory fitness (VO2max) with DHEAS, IGF-1 and testosterone in a group of healthy elderly people. METHODS: Fifty independent, community dwelling elderly subjects (25 mens and 25 womens) aged from 66 to 84 volunteered to participate in the study. PA was evaluated by the questionnaire and expressed using two activity indices: mean habitual daily energy expenditure (MHDEE) and the daily energy expenditure corresponding to leisure time sports activities (Sports Activity). Pmax and optimal shortening velocity (vopt) were measured on a Ergopower dynamometer. The Pmax was expressed relative to body mass, Pmax/kg (W kg-1), and relative to the mass of the two quadriceps muscles, Pmax/Quadr (W.kgQuadr-1). VO2max has been measured during a maximal treadmill exercise. RESULTS: In women, IGF-1 correlated significantly with MHDEE (r = 0.54, P = 0.004), Pmax/kg (r = 0.54, P = 0.004) and Pmax/Quadr (r = 0.46, P = 0.02), whereas DHEAS with MHDEE (r = 0.54, P = 0.004), Sports Activity (r = 0.65, P < 0.001), VO2max (r = 0.46, P = 0.02), Pmax/kg (r = 0.46, P = 0.02) and Pmax/Quadr (r = 0.55, P = 0.004). No such correlation was found in men. CONCLUSION: These findings confirm that in healthy elderly women physical activity, cardiorespiratory fitness and quadriceps muscle function are similarly related to levels of circulating DHEAS and IGF-1 suggesting a favourable influence of exercise on anabolic hormonal production in the elderly.

Aged↗
PubMed2001

Comparison of progesterone concentration determination by 12 non-isotopic immunoassays and gas chromatography/mass spectrometry in 99 human serum samples.

A single serum progesterone determination may be highly predictive for early pregnancy and in vitro fertilisation and embryo-transfer outcomes. We therefore compared 12 direct non-isotopic progesterone immunoassays with gas-chromatography/mass spectrometry (GC/MS). For each assay, data from the analysis of 99 individual sera were compared with data obtained by GC/MS, using regression and bias plot analyses and the ratio method. We observed a larger difference in concentration between high and low values and a broader distribution of results for immunoassays than for GC/MS. All immunoassays displayed bias in the calibration process and a lack of specificity and/or sensitivity, to various degrees. We tried to identify the parameters of the assay procedure that might contribute to these discrepancies. None of the criteria investigated (antibodies, control and preparation of calibrators, blocking agents and choice of tracer) had a significant effect when studied alone.

Chemistry, Clinical↗
PubMed2001

Lack of correlation between 6-month fluctuations in habitual physical activity and testosterone. Concentrations in elderly subjects.

BACKGROUND: To examine the influence of long-term modifications in habitual physical activity (PA) on resting total testosterone (TT) concentrations in a group of healthy elderly subjects. METHODS EXPERIMENTAL DESIGN: 6-month prospective study. SETTING: University research departments of exercise physiology and geriatric medicine. PARTICIPANTS: thirty-one independent, community dwelling elderly subjects (16 men and 15 women) aged > 65 who volunteered to participate. INTERVENTIONS: correlational study. MEASURES: PA was evaluated by a questionnaire QAPSE (Questionnaire d Activité Physique Saint-Etienne) and expressed by two activity indices: mean habitual daily energy expenditure (MHDEE) and daily energy expenditure corresponding to leisure time sports activities (Sports activity index). RESULTS: Changes in resting TT concentrations were not related to changes in MHDEE (r = -0.28; p = 0.30 and r = -0.001; p=0.99) and Sports activity (r = -0.30; p = 0.26 and r = -0.05; p = 0.85) in men and women, respectively. Similarly, relative (%) changes in TT were not related to relative changes in MHDEE (r = -0.16; p=0.55 and r = 0.17; p=0.55) and Sports activity (r = -0.11; p=0.68 and r = 0.02; p = 0.92). CONCLUSIONS: The levels of habitual PA undertaken by an average senior do not appear to affect TT levels in healthy active elderly men and women.

Aged↗
PubMed2000

Leg extensor power and dehydroepiandrosterone sulfate, insulin-like growth factor-I and testosterone in healthy active elderly people.

We examined the association between quadriceps muscle function and serum levels of dehydroepiandrosterone sulphate (DHEAS), insulin-like growth factor I (IGF-I) and testosterone in a group of healthy elderly people. Fifty-three independent, community-dwelling elderly subjects (26 men and 27 women) aged from 66 to 84 years volunteered to participate in the study. Physical activity (PA) was evaluated by a questionnaire. Quadriceps maximal muscle power (Wmax) and optimal shortening velocity (v(opt)) were measured on a friction-loaded non-isokinetic cycle ergometer. The Wmax is expressed in relation to body mass (W(max/kg), W x kg(-1)), and in relation to the mass of the two quadriceps muscles (W(max/Quadr), W x kg(Quadr(-1))). In women, when adjusted for age, anthropometric measurements and PA indices, IGF-I correlated significantly with W(max/kg) (partial correlation: r = 0.59; P = 0.001), W(max/Quadr) (r = 0.58; P = 0.002) and v(opt) (r = 0.53; P = 0.004), whereas DHEAS was correlated significantly with W(max/kg) (r = 0.54; P = 0.003) and W(max/Quadr) (r = 0.58; P = 0.002). No such correlation was found in men. These findings indicate that in healthy elderly women lower values for quadriceps muscle Wmax and v(opt) are related, independently of age, anthropometric measurements and PA indices, to lower circulating levels of DHEAS and IGF-I.

Aged↗
PubMed2000

Determination of plasma methoxyamines.

The determination of plasma methoxyamines is the most informative parameter for the diagnosis of pheochromocytoma. Very good sensitivity and specificity are necessary for this. The measurement of deconjugated (free plus sulfate-conjugated) metanephrines is more useful. Concentrations are 10-fold higher than free metanephrine concentrations. The methodology generally uses a column purification and high performance liquid chromatography with electrochemical detection. We have tested six commercial columns used for the purification step. We chose a rapid and reliable method with a mixture of strong cation-exchange and strong anion-exchange groups bonded onto a silica column. This protocol has been validated with samples of plasma from normal subjects, healthy elderly people, renal failure patients and patients with pheochromocytoma.

Chromatography, High Pressure Liquid↗
PubMed1999

Influence of acute and chronic exercise on insulin-like growth factor-I in healthy active elderly men and women.

We examined the influence of physical activity (PA) and acute resistance exercise on insulin-like growth factor I (IGF-I) in 39 healthy, independent, community-dwelling elderly volunteers (14 men and 25 women) aged from 66 to 84. In a longitudinal non-interventional study, we compared the fluctuations in IGF-I levels and changes in habitual PA over a 6-month period. PA was evaluated by a questionnaire QAPSE (Questionnaire d'Activité Physique Saint-Etienne), and expressed by two activity indices: mean habitual daily energy expenditure (MHDEE), and daily energy expenditure corresponding to leisure time sports activities (sports activity index). In an experimental design we compared IGF-I levels before, at 1 and 15 minutes after short quadriceps muscle exertion (10 consecutive repetitions) carried out with optimal muscle power development. Changes in IGF-I levels over a 6-month period were positively related to changes in MHDEE (r = 0.41; p<0.01), and sports activity (r = 0.40; p<0.02). When analyzed by gender, these correlations were still statistically significant in women (r = 0.39; p = 0.05 and r = 0.41; p<0.05), but not in men (r = 0.36; p = 0.21 and r = 0.20; p = 0.50). No changes (p = 0.17) were observed in serum IGF-I concentrations after the acute exercise protocol. These findings indicate that IGF-I levels are positively related to fluctuations in habitual PA, at least in women. Further research is needed to establish the best intensity and duration of exercise training to induce these changes.

Aged↗
PubMed1998

Physical activity and dehydroepiandrosterone sulphate, insulin-like growth factor I and testosterone in healthy active elderly people.

OBJECTIVE: to examine the association of physical activity and cardio-respiratory fitness with dehydroepiandrosterone sulphate (DHEAS), insulin-like growth factor I (IGF-I) and testosterone in healthy elderly people. DESIGN: cross-sectional study. SETTING: university research department and department of geriatric medicine. PARTICIPANTS: 60 independent, community-dwelling elderly subjects (26 men and 34 women) aged 66-84 who volunteered to participate. MEASUREMENTS: physical activity was evaluated by the Questionnaire d'Activité Physique Saint-Etienne and expressed by three indices: mean habitual daily energy expenditure (MHDEE), daily energy expenditure (DEE) [comprising activities with intensities corresponding to at least three metabolic equivalents (MET; 3.5 ml.kg1 x min1 of oxygen consumption)] and sport activity. Cardio-respiratory fitness was expressed by maximal oxygen consumption (VO2max). RESULTS: In women, DHEAS correlated with VO2max (partial correlation: r=0.33; P=0.05), MHDEE (r=0.50; P=0.002), DEE > 3 METs (r=0.49; P=0.003) and sport activity (r=0.35; P=0.04) whereas IGF-I correlated with MHDEE (r=0.48; P=0.004). DHEAS was correlated with IGF-I (r=0.43; P < 0.02) and with testosterone (r=0.41; P < 0.02). No such correlation was found in men. CONCLUSION: lower habitual physical activity is related to lower levels of circulating DHEAS and IGF-I independently of age and anthropometric measures. Lower maximal aerobic capacity is associated with lower DHEAS concentrations, in healthy elderly women.

Activities of Daily Living↗
PubMed1997

Convenient chromatographic prepurification step before measurement of urinary cortisol by radioimmunoassay.

We applied various prepurification protocols (extraction with different solvents, liquid/solid separation on bonded silica media, Celite, and Sephadex LH20 chromatography) with a range of commercially available RIA kits to measure cortisol in urine samples. We then compared the results with the concentrations measured by a HPLC method validated with reference to isotope dilution gas chromatography-mass spectrometry. We conclude that chromatography on a commercial, prepacked diol minicolumn (Waters Sep-Pak Vac RC) in combination with dichloromethane extraction is a convenient and very effective purification step before RIA of urinary cortisol in patients not receiving corticoid medication. We tested numerous steroids for interference and found that free polar cortisol derivatives (hydroxylated or hydrogenated) could only partially account for the overestimations routinely encountered when free urinary cortisol concentrations are measured by direct RIA.

Adult↗
PubMed1996

European collaborative study of LH assay: 3. relationship of immunological reactivity, biological activity and charge of human luteinizing hormone.

This report describes the results of the third part of the collaborative study organized by a working group sponsored by the Community Bureau of Reference of the European Community Commission. The aim of the present work was to establish the link between immunoreactivity and biological activity of human LH, thus allowing to determine the antigenic domains of the molecule involved in the induction of the biological effect. The relationship between immunoreactivity and electric charge of hLH was also studied. This work allowed to further apprehend hLH isomorphism and its role in discrepancies observed among hLH assays and clinical status. It also made the feasibility of measuring biologically active isoforms by an immunological method to be assessed. The effect of 36 mAb with known epitopic specificity, was evaluated on both hLH binding to rat membrane receptor and hLH induced production of testosterone by porcine Leydig cells. All the epitopes located on the beta subunit were found to be strongly involved in the biological activity whereas 4/9 and 10/18 epitopes present on the alpha subunit or specific for the holomolecule respectively appeared weakly involved. Assaying biological hLH using immunological method would require that mAb specific for all the epitopes involved in the receptor activation be tested, and thus appears presently unsuitable for routine clinical evaluation. In the previous work some LH immunoassays were found to underestimate LH concentrations (J. Endocrinol. Invest 1994, 17: 397-406 and 407-416). The mAb used in liquid phase in these kits were found in the present work to be directed against the domains of LH weakly involved in the activation of the receptor and would suggest that bioactive LH would be misevaluated by these kits. The immunoreactivity of hLH isoforms separated by isoelectric focusing (IEF) in liquid phase was also determined. IEF allowed to separate three groups of hLH isoforms but none of them exhibited a specific discriminating pattern of immunoreactivity when they were tested against a panel of mAb. It suggests that, in our experimental conditions, the electric charge and the immunoreactivity of hLH were not closely linked.

Animals↗
PubMed1996

[Measurement of salivary cortisol with four commercial kits].

Salivary cortisol was determined with four commercially available immunoassays: one enzyme-immunoassay (Cortisol Biotrol), two fluoro-immunoassays (TDX, Abbott; Stratus, Baxter) and one radioimmunoassay (Coat-A-Count, Behring). In order to improve the sensitivity of these immunoassays, it was necessary to increase sample volumes. Thus an extraction step had to be included in the procedure. It was performed with either methylene chloride or Bond Elut. However, the Coat-A-Count kit may be applied directly on salivary aliquots. The results obtained were compared to those yielded by the reference technique which includes a chromatographic step on Sephadex LH 20. According to the present data (n = 20) no kit appears to be adequate for salivary cortisol measurement at any level, at least in the conditions applied in this study. However, the introduction of a chromatographic step in the procedure improved greatly the specificity. Nevertheless, the best results were obtained with the Coat-A-Count kit. Indeed, they were generally similar to those of the reference technique, but some discrepancies were observed at low levels.

Humans↗
PubMed1995

[Value of immunoassay of hCG for the determination of high plasma concentrations].

The serum concentration of human chorionic gonadotrophin is higher in trisomy 21 than in normal pregnancy. Our study aimed at comparing 17 commercial kits, both those for measuring high concentrations and others for diagnosis and initial follow-up of pregnancy under specific conditions, ie for measuring hCG concentrations between weeks 14 and 18 of pregnancy. All kits were satisfactory; however, usual values for the gestational weeks concerned need to be established for each reagent.

Chorionic Gonadotropin↗
PubMed1995

[Validity of immunochemical assays for blood estradiol. Study conducted in 1994].

Since 1989 many kits have been commercialized for measuring estradiol by non-isotopic immunoassays which largely contributed to the diffusion of this parameter. Rapidly, in quality control schemes, a wide dispersion of results has been observed. In this paper, the kits' characteristics (precision, accuracy and detection limit) have been studied and compared to a reference method (gas chromatography-mass spectrometry). In addition, estradiol determinations in patients with various pathophysiological situations have been performed to underline the difficulties of interpretation of this analyte when clinicians compare results given by the different kits. This work demonstrates that precision and accuracy varied both with the kit and the level of concentration of estradiol and gives better results for high concentrations of estradiol. In seven out of the 12 kits, the limits of detection are in good agreement with those announced by manufacturers. On the contrary, the determination on patients sera gives results with a high variability with no systematic error.

Adolescent↗
PubMed1994

[Recommended methods for the determination of catecholamines and their metabolites in urine. Significance of results in the diagnosis and follow-up of pheochromocytoma and neuroblastoma].

Laboratory investigation of catecholamines is useful for the clinician in the diagnosis and management of phaeochromocytoma and neuroblastoma. This work summarizes current knowledge on catecholamines and their metabolites and discusses the main indications for their determination. It also examines the most practical methods for studying the secretion of these hormones, ie extraction, separation and quantification using high performance liquid chromatography coupled with electrochemical detection. The workshops attended by the members of the catecholamines working party of the French Clinical Biology Society and phaeochromocytoma and neuroblastoma specialists enabled the role of such determinations in the diagnosis and management of these diseases to be clarified.

Adolescent↗
PubMed1994

[Immunoassay and measurement of the biological activity of serum hLH: results obtained of a multicenter study].

The discrepancy between results obtained using different anti-hLH antibodies available on the market led us (in the context of a contract with the CNAMTS) to compare the results of hLH immunoassays (eight different reagents) with those of hLH bioassays based on the measurement of the steroidal activity of this hormone on mouse, rat or pig testicular preparations (five methodologies). Twenty-nine samples of serum or human serum pools were tested. The values resulting from these tests reveal differences linked to the nature of the antibodies or to the methodological conditions used for the testicular preparations. Some antibodies seem unable to identify some hLH forms which, however, can be detected by biological methods.

Adult↗
PubMed1992

Determination of urinary cortisol with three commercial immunoassays.

Urinary cortisol determination was performed with three commercially available immunoassays: one enzyme-immunoassay (Cortisol Biotrol) (EIA) and two radioimmunoassays: Quanticoat Cortisol (Kallestad Diagnostics) (KD-RIA) and GammaCoat Cortisol (Clinical Assays) (CA-RIA). Four procedures were carried out. Procedure I (methylene chloride extraction) was applied to EIA and CA-RIA and procedure II (ethyl acetate extraction) to KD-RIA. Procedure III combining procedure I and column chromatography on Sephadex LH 20 in methylene chloride was applied to the three kits. Procedure IV consisting of carbon tetrachloride preextraction and extraction with cyclohexane-ethyl acetate (50:50, v/v) was applied to CA-RIA. The results obtained were compared with those of the reference technique, "on-line" HPLC with u.v. detection. Two groups of results were arbitrarily considered, those below (n = 28) and those above (n = 6) 270 nmol/l. In the first group, the results were markedly overestimated when the procedure was limited to solvent extraction. Conversely, the third procedure proved the efficiency of the chromatographic step since specificity was greatly improved in the three cases, the levels obtained with either kits being similar to those of the reference technique. The second group of results (above 270 nmol/l) yielded by the three kits were not always higher than those of HPLC when the procedure was limited to solvent extraction. When column chromatography was included in the procedure, the results were comparable to those of HPLC in three cases and lower in the three others. Since, the latter samples were collected after cortisol administration, and overestimated cortisol values obtained by HPLC might be due to the interference of some cortisol metabolites.

Humans↗
PubMed1992

[Description of cell line established from human thyroid papillary cancer and secreting human chorionic gonadotropin hormone].

One of the difficulties in characterization of the oncogenes involved in thyroid carcinogenesis is the production of cell lines. Arising from a poorly differentiated thyroid papillary carcinoma we have established a cell line synthesizing the thyroglobulin and human chorionic gonadotropin (alpha and beta subunits) (HCG) hormones. These cells will allow research of the oncogenes involved or potentially involved in thyroid papillary carcinomas and evaluation of the role of the autocrine secretion of HCG.

Carcinoma, Papillary↗
PubMed1991

Specific assay for unconjugated dehydroepiandrosterone in human plasma by capillary gas chromatography with electron-capture detection.

A specific and sensitive method for the determination of unconjugated dehydroepiandrosterone in plasma is described. After extraction and purification of the extracts on a Celite column, the iodomethyldimethylsilyl ether derivative of dehydroepiandrosterone was isolated on an aluminium oxide column and assayed by gas chromatography with electron-capture detection. The method is sensitive: sample volumes of 0.5-1 ml are sufficient for the determination of dehydroepiandrosterone in plasma of normal male and female subjects aged 1-80 years. The assay is highly specific and has the potential to be used as a reference method for the determination of unconjugated dehydroepiandrosterone in biological samples.

Adolescent↗