Search PubMed⌕ Search

Biomedical subjects

J P Louvet

Publications and source records attributed to J P Louvet.

At least 19 recordsLinked to original sources
PubMed1998

Uncoupling protein-2 messenger ribonucleic acid expression during very-low-calorie diet in obese premenopausal women.

Uncoupling protein-2 (UCP2) is a mitochondrial protein expressed in a wide range of human tissues. By uncoupling respiration from ATP synthesis, UCP2 might be involved in the control of energy expenditure. We have investigated UCP2 gene expression in human adipose tissue. In eight subjects, we found a positive correlation (r = 0.91, P < 0.002) between subcutaneous and visceral fat depots UCP2 messenger RNA (mRNA) levels, suggesting that UCP2 mRNA level in subcutaneous adipose tissue is a good index of UCP2 gene expression in whole body adipose tissues. The effect of a 25-day very-low-calorie diet un UCP2 mRNA level and resting metabolic rate was investigated in eight obese premenopausal women. There was no difference in UCP2 mRNA levels before and during the diet. After 25 days of hypocaloric diet, a positive correlation was found between adipose tissue UCP2 mRNA level and resting metabolic rate adjusted for lean body mass (r = 0.82, P < 0.01). These results show that very-low-calorie diet, unlike short-term fasting, is not associated with an induction in UCP2 mRNA expression, and that adipose tissue UCP2 mRNA levels may be related to variations in resting energy expenditure in humans.

Adipose Tissue↗
PubMed1996

Hormonal changes related to eating behavior in oligomenorrheic women.

The aim of this study was to determine those hormonal alterations in the gonadotropin-ovarian axis that are related to eating behavior in oligomenorrheic patients. We studied 74 oligomenorrheic women aged 26.2 +/- 0.8 years, divided into group IA (N = 13) with eating disorders, group IB (N = 61) without eating disorders and 18 normally cycling controls aged 29.2 +/- 1.6 years (group II). No subject had ovarian failure, pituitary disease, thyroid dysfunction or was taking any drug. Blood samples were taken on days 3-6 after the last menses. Luteinizing hormone (LH) was measured in two plasma pools, each made up of three samples taken at 30-min intervals, starting at 15.00 h (LH-15h) and 09.00 h (LH-9h), which allowed the mean LH (mLH) and variability in LH (V-LH: percentage increase from the lower to the higher of the two LH values) to be calculated. Follicle-stimulating hormone (FSH), sex steroids, and gonadotropin-releasing hormone-stimulated LH (sLH) and -FSH (sFSH) were also evaluated. Eating behavior was evaluated with the EAT questionnaire; the EAT 26 score, the dieting score (DS) and bulimia score (BS) were calculated. Dietary intake was evaluated in 35 group IB patients based on food diaries analyzed with the REGAL program, to evaluate daily calorie intake (Cal) and calories provided by carbohydrates (Carb), lipids (Lip) and proteins (Prot). Comparisons between groups were done by analysis of variance (followed by the Fisher PLSD test) and the Kruskal-Wallis test. Groups IA, IB and II did not differ regarding age, body mass index, LH-9h, LH-15h, mLH, FSH, sLH, sFSH, estradiol or dehydroepiandrosterone sulfate; group IA had a higher V-LH than group II (p < 0.02) and a higher testosterone level than groups IB and II (p < 0.05). Positive correlations were found between V-LH and DS (p < 0.01) and BS (p < 0.05), and between testosterone and BS (p < 0.02) and DS (p < 0.05). The V-LH was negatively correlated with Cal and Carb, and testosterone was positively correlated with Cal and Lip. In patients referred for oligomenorrhea, it is concluded that testosterone levels and variability of LH levels are related to eating behavior.

Adult↗
PubMed1995

[Use of a gonadoliberin agonist with or without gonadoliberin pulses for ovulation induction in ovarian dystrophies].

OBJECTIVES: Determine whether ovulation in dystrophic ovaries treated with GnRH agonist followed by GnRH pulses is due to the GnRH pulse or is patient-dependent. SITE. Endocrinology department, CHU Purpan, Toulouse, France. METHODS: Fifteen infertile patients, age range 22 to 35 years, with ovarian dystrophy were given GnRH agonist (Decapeptyl, 3.75 mg IM on day 3 of the cycle). In 5 patients, an IV pulse of GnRH was then given (6 micrograms/90 min). STATISTICAL ANALYSIS: Mann-Whitney U test, corrected chi 2 test. RESULTS: Ovulation was achieved in 8/15 cases (3/5 with and 5/10 without pulsatile GnRH p = NS) and 3 pregnancies (without pulsatile GnRH). Before treatment LH was higher in patients who had an ovulation. CONCLUSION: Ovulation can be achieved after GnRH agonist treatment in patients with dystrophic ovaries, with or without pulsatile GnRH, particularly if the initial LH levels are high.

Adult↗
PubMed1994

Luteinizing hormone secretory pattern before and after removal of Leydig cell tumor of the testis.

We studied the luteinizing hormone (LH) secretory pattern in three patients, aged 30, 23 and 43 years, with gynecomastia due to Leydig cell tumor of the testis, before and 6 months after unilateral orchidectomy. The results were compared to those of 11 normal fertile controls aged 20-35 years. Blood sampling was done at 20-min intervals from 22.00 h to 10.00 h. The LH data were analyzed with the Cluster analysis algorithm with "optimal parameters for LH male data" to determine the pulse interval and pulse amplitude. The Expfit program was applied to LH pulses to calculate the apparent half-life of immunoreactive LH. Before surgery, when compared to controls, the patients had a low to normal testosterone/estradiol ratio (0.053, 0.110, 0.046 vs 0.148 +/- 0.038) and mean LH levels (1.96, 3.7, 2.55 vs 4.0 +/- 1.9 IU/l), decreased pulse amplitude (2.65, 3.01, 2.21 vs 3.31 +/- 1.41 IU/l) and reduced apparent half-life of LH (74, 69, 78 vs 97 +/- 16 min). After removal of the Leydig cell tumor, the testosterone/estradiol ratio returned to the normal range (0.141, 0.177, 0.093) while an increase in mean LH levels (5.75, 7.90, 4.88 IU/l), LH pulse amplitude (3.07, 6.05, 2.86 IU/l) and apparent half-life of LH (138, 106, 104 min) was observed in all three patients. Our data indicate that endogenous hyperestrogenism in patients with Leydig cell tumor of the testis results in an inhibition of LH secretion, and suggests that such inhibition could result from a reduction in pulse amplitude and apparent half-life.

Adult↗
PubMed1993

Sex-hormone-binding globulin and protein-energy malnutrition indexes as indicators of nutritional status in women with anorexia nervosa.

Serum sex-hormone-binding globulin (SHBG), transferrin, prealbumin, retinol-binding protein, and ceruloplasmin concentrations were evaluated in 12 women with anorexia nervosa before and after weight gain and in 12 healthy women with normal weight. The serum SHBG concentrations were higher in patients with anorexia nervosa before weight gain than in control subjects and they returned to the normal range after weight gain. The changes of SHBG concentrations were not associated with any change in plasma testosterone, estradiol, or free thyroxin concentrations. The body mass index in our patients after weight gain was lower than in control subjects. Prealbumin, retinol-binding protein, ceruloplasmin, and transferrin in anorectic patients before weight gain did not differ from those of the control subjects and increased after weight gain. The changes of serum SHBG concentrations in patients with anorexia nervosa during weight gain make SHBG determination a reliable index of nutritional status in this type of eating disorder.

Adolescent↗
PubMed1992

Increased platelet sodium-proton exchange rates in insulin-dependent (type 1) diabetic patients with nephropathy and hypertension.

In order to assess the potential role of the plasma membrane sodium-proton (Na+/H+) exchanger in the pathogenesis of diabetic nephropathy, we investigated 32 insulin dependent (type 1) diabetic patients and 21 control subjects. We tested the Na+/H+ exchange as the rate of amiloride sensitive and sodium dependent volume gain of platelets suspended in sodium propionate. Patients with diabetic nephropathy had significantly increased rates of Na+/H+ exchange (0.31 +/- 0.06 s-1 x 10(-2)) when compared to those without nephropathy (0.24 +/- 0.07, p less than 0.05) or to a control group (0.23 +/- 05, p less than 0.05). Nine patients who were classified as hypertensive had a highly significant increase in the Na+/H+ exchange rates when compared to 23 non-hypertensive diabetic patients: 0.33 +/- 0.04 versus 0.24 +/- 0.06 (p less than 0.001). There was no significant correlation between the Na+/H+ exchange rates and age, diabetes duration, glycated hemoglobin or fructosamine levels on the day of the test. In summary, the data presented here demonstrate an increase in the Na+/H+ exchange rate in insulin-dependent diabetic patients with nephropathy and hypertension.

Adolescent↗
PubMed1992

[Activity of platelet sodium-proton exchanger, microalbuminuria and insulin-dependent diabetes].

The plasma membrane Na+/H+ exchanger is a ubiquitous system which plays a role in the regulation of intracellular pH and the control of cell growth. In order to assess the potential role of this system in the pathogenesis of diabetic nephropathy, we investigate 42 normotensive insulin-dependent diabetic patients with or without microalbuminuria. We tested the platelet Na+/H+ exchange as the rate of amiloride sensitive and sodium dependent volume gain of cells suspended in sodium propionate. Urinary albumin excretion (UAE) was assayed by radioimmunoassay on a 24 h sample; the glomerular filtration rate (GFR) and the renal plasma flow were determined by 99 m Tc-DTPA and 1231 l-hippuran respectively. Thirty patients (group 1) had EUA > 30 mg/24 h (m +/- sd: 11 +/- 7 mg/24 h), 12 patients (group 2) had microalbuminuria (62 +/- 30 Mg/24 h, range from 35 to 136 mg/24 h). The platelet Na+/H+ exchange rate was significantly increased in patients of group 2: 0.34 +/- 0.01 versus 0.26 +/- 0.06 s-1 x 10(-2) (p < 0.005). There was no significant difference between these two groups regarding blood pressure (116 +/- 14/71 +/- 7 versus 119 +/- 12/73 +/- 5 mmHg), age, diabetes duration, glycated hemoglobin or fructosamine levels. On the whole population, we found a significant positive correlation between the platelet Na+/H+ exchange rate and the UAE (r = 0.57, p < 0.001) and with the glomerular filtration fraction (r = 0.43, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Value of nocturnal blood pressure in treated non-insulin-dependent hypertensive patients].

The purpose of the study was to evaluate the loss of nocturnal (N) decline in blood pressure (BP) in type II treated hypertensive diabetics. The study concerned 36 hypertensive diabetics 59 +/- 10 years old, 20 men and 16 women, with poor metabolic control (HbA1C: 9.6 +/- 3%), without dysautonomia; 14 had macroproteinuria and/or microalbuminuria (mu alb) (< 30 micrograms/min). An ambulatory BP monitoring (Spacelabs 90207) was performed in all patients. Left ventricular mass index (LVMI) and E/A were determined by Doppler-echocardiography. Two groups (G) were individualized: G1 (n = 17), with a normal circadian rhythm (diurnal and N.BP significantly different); G2 (n = 19) with a loss of N decline in systolic (S) and diastolic (D) BP or both; and compared to non diabetic treated hypertensive controls (G3). There was no difference neither in LVMI (125 +/- 43 g/m2), E/A (0.7), 24 h-mean (M) BP in the three groups, nor in HbA1C levels and mu alb occurrence in G1 and G2. Mean N.SBP and mean N.DBP were more closely related to LVMI in G2 than in G1 and G3. [table: see text] Half of these hypertensive diabetics, with bad metabolic control, have an altered circadian BP pattern; the prognostic value of nocturnal BP, related to LVMI despite the antihypertensive treatment, is suggested.

Aged↗
PubMed1992

A long-acting repeatable form of bromocriptine as long-term treatment of prolactin-secreting macroadenomas: a multicenter study.

OBJECTIVE: To assess the efficacy and tolerability of monthly injections of the long-acting repeatable bromocriptine in patients with macroprolactinomas. DESIGN: Open and prospective trial. SETTING: This multicenter trial was carried out in seven university hospitals. PATIENTS: Forty-two patients with prolactin (PRL)-secreting macroadenomas. INTERVENTIONS: Fifty to 200 mg of the drug were administered intragluteally every 28 days for 6 to 24 months. MAIN OUTCOME MEASURES: The efficacy was assessed by repetitive plasma PRL measurements, visual field determinations, and computed tomography scan examinations. RESULTS: After the first 50-mg injection, the mean percentage decrease of PRL levels was 71% from baseline on day 14; between days 1 and 28, PRL levels were suppressed to normal in nine cases, and a clear tumor shrinkage was documented in 21% of the patients. Normalization of PRL secretion was obtained in 62%, and a clear-cut reduction in tumor size in 50% of the patients after 6 months of treatment. CONCLUSIONS: The long-acting repeatable form of bromocriptine was a well tolerated and quickly effective treatment in most of these patients with macroprolactinomas.

Adenoma↗
PubMed1991

Fluoride therapy in postmenopausal osteopenic women: effect on vertebral and femoral bone density and prediction of bone response.

Fifty-two postmenopausal women (mean age 60 +/- 5 years) with low BMD (less than -2SD of young adult values) but who had not experienced previous crush fracture were treated with 50 mg of sodium fluoride (NaF), 1 g of calcium and 400 IU of vitamin D2 per day for 2 years. Repeated vertebral and femoral BMD measurements were made and compared with those of a control group consisting of 16 untreated women. Serum alkaline phosphatase and osteocalcin, blood and urinary fluoride levels were measured regularly to determine their predictive value on bone response. 18 of 52 (35%) of the treated patients experienced side effects (29% gastric, 4% lower extremity pain syndrome) but only in 6 cases (12%) was it necessary to discontinue treatment. In neither of the two groups was any fracture recorded (vertebral or otherwise). Among the 43 women who were treated for at least 2 years, 21 (49%) were considered to have responded (i.e., with an increase of vertebral BMD greater than 0.043 g/cm2). There was a mean linear increase in BMD in this group of 0.0041 g/cm2 per month (i.e., 5.5% per year). On the other hand in the non-responder group and in the control group, vertebral BMD either remained stable or decreased. However no difference was detected between the two groups (treated and controls) at the femoral site after 2 years; both groups showed a significant decrease in BMD. The responders had a lower initial osteocalcin level and treatment led to a relatively greater increase in osteocalcin.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Luteinizing hormone pulse frequency and in vitro bioactivity in male idiopathic infertility.

We investigated 51 patients with idiopathic oligospermia and 10 control subjects. Blood samples were collected every 20 minutes from 10 P.M. to 10 A.M. and luteinizing hormone (LH) pulsatility was analyzed. A pool of all samples obtained from each subject was used to measure bioactive LH in an in vitro mouse Leydig cell bioassay and immunoactive LH in an immunoradiometric assay. Mean immunoactive LH pulse frequency was higher and mean bioactive to immunoactive LH ratio was lower in infertile men than in controls. There was a significant negative correlation between bioactive LH to immunoreactive LH ratio and LH pulse frequency. These data indicate that the defect in the gonadal axis in oligospermic men resides not in the hypothalamic-pituitary function but rather in the testis itself.

Adult↗
PubMed1991

Correlations between mean LH levels and LH pulse characteristics: differences between normal and anovulatory women.

OBJECTIVE: Since LH secretion occurs as a series of pulses, relationships between mean LH levels and LH pulse characteristics are to be expected. The aim of this study was to determine whether such relationships are similar in normal women and anovulatory patients. DESIGN: We studied the correlations between mean LH levels and the products amplitude x frequency and area x frequency of LH pulses in normal women and in patients with disorders of ovulation. Blood samples were taken from each subject every 10 minutes during 6 hours on the 8th day after the last menses. PATIENTS: The patients were divided into three groups: patients with polycystic ovary syndrome (n = 11), patients with idiopathic anovulation (n = 14) and patients with short luteal phase (n = 13). Their results were compared to those of 12 normal women. MEASUREMENTS: LH was evaluated with an immunoradiometric assay. LH data were analysed with a 3 standard deviation threshold criterion for significant peaks, and with cluster analysis algorithm using 1, 2.5 and 5% false positive error rates and 'optimal parameters' (which give less than 5% false positive and false negative error rates in LH male data). RESULTS: Highly significant correlations between amplitude x frequency, area x frequency and mean LH were found in normals and patients with short luteal phase; no significant correlation was found in patients with polycystic ovary syndrome, while significant correlations were found in patients with idiopathic anovulation only with some of our criteria for peak detection. CONCLUSION: The differences that we found between the groups suggest that when commonly used methods are employed to determine LH pulse characteristics, most of the significant LH pulses are taken into account in normals and patients with short luteal phase, but not in anovulatory patients, especially in patients with polycystic ovary syndrome. This method using two correlations appears to be a simple and useful way to show the differences in the mechanisms by which mean LH levels are achieved in normal subjects and patients.

Adult↗
PubMed1991

LH pulsatility and in vitro bioactivity in women with anorexia nervosa-related hypothalamic amenorrhea.

LH nocturnal pulsatility and bioactivity to immunoreactivity (B/I) ratio were determined in 16 patients with anorexia nervosa-related hypothalamic amenorrhea and low sex steroid levels, and in 12 normal women in the midfollicular phase. The patients were subdivided into 2 groups: IA (N = 7) without, and IB (N = 9) with documented recent weight gain. Blood samples were taken from each subject at 10-min intervals from 00.00 to 06.00 h. Immunoreactive LH data were analysed with cluster analysis algorithm. A pool of aliquots from all the samples was used to evaluate bioactive LH, immunoreactive LH and LH B/I ratio in each subject. LH pulse frequency was lower in Group IA than in controls, whereas it did not differ significantly between Group IB and controls. LH pulse amplitude was lower in Group IA, and higher in Group IB than in controls. LH B/I ratio was below the control range in 3/16 patients. In conclusion, persistent hypothalamic amenorrhea does not require a permanent inhibition of the GnRH pulse generator; transient inhibition of pulsatility and qualitative abnormalities of gonadotropins could be involved in the mechanism, at least in some patients.

Adolescent↗
PubMed1991

[Transitory bone loss during substitution treatment for hypothyroidism. Results of a two year prospective study].

The authors report the results of a prospective study designed to assess changes in vertebral and femoral bone density during the first two years of replacement therapy in 10 patients with hypothyroidism (4 men, 6 women). During the first year, bone density measured by dual photon absorptiometry fell significantly in the lumbar vertebrae (-5.4%), neck of the femur (-7%) and the trochanteric region (-7.3%). This bone loss was accompanied by an early increase in serum osteocalcin levels, urinary calcium/urinary creatinine ratio and in Sex Hormone Binding Globulin. During the second year, there was complete recovery of values of vertebral and trochanteric bone density, while density of the neck of the femur remained significantly lower than initial values. None of the patients showed any evidence of overdose during the period of monitoring of clinical and laboratory (free T4, total and free T3, ultra-sensitive TSH) parameters. This transitory bone loss could be indicative of a state of tissue hyperthyroidism and/or "hypersensitivity" of hypothyroid bone to the action of thyroid hormones. Its influence on the subsequent risk of fracture remains unclear. In the current state of knowledge, measurement of vertebral and femoral bone density appears to be indicated in patients given long term treatment which suppresses TSH, or requiring replacement therapy for severe hypothyroidism. Any demineralisation prior to treatment could justify the temporary prescription of an antiosteoclastic agent.

Adult↗
PubMed1991

[Short-term effect of delayed-action injectable bromocriptine in macroprolactinoma. French multicenter study].

In this prospective multicenter trial, 61 patients presenting with a macroprolactinoma were studied over a 1 month-period following a single 50 mg intragluteal injection of the long-acting repeatable (L.A.R.) form of bromocriptine. The effects of the drug were evaluated mainly by repetitive plasma prolactin measurements on days 1, 3, 7, 14 and 28 after injection, and by repeated visual-field and computed tomography scanning examinations. Normalization of PRL levels was obtained in 23% of patients during the first month following injection. In 6 patients (9.8%), PRL values remained within normal range on day 28 after injection. In these latter patients, PRL levels were significantly lower than in the patients whose PRL values were not normal on day 28 (312 +/- 111 vs 2454 +/- 484 ng/ml [m +/- SEM]). The mean lowest PRL levels were achieved on day 3. The mean percent maximal decrease in PRL levels ranged between 70 and 72% from days 3 to 14 but constantly remained below 50% in 6 patients. An improvement in visual field was observed by day 7 in 45% of patients presenting initially with visual field defects. In particular, in half of the patients with bilateral quadranopsia or hemianopsia, such visual impairments had disappeared after 1 month of treatment. Computed tomography scanning examinations showed in 11% of the patients a more than 20% reduction in tumor mass by day 7 following injection. On day 28, the percent reduction in tumor size was 20-40% in 28% and above 40% in 10% of the patients. Most adverse effects (digestive symptoms, dizziness, postural hypotension) were observed during the first 24 hours of treatment. Local and systemic tolerability was in general good. In macroprolactinoma patients, a single 50 mg injection of bromocriptine LAR was thus able to achieve in the short-term a clear cut reduction in tumor size in 2/5 patients and normalization of PRL levels in 1/10 of patients. A study of the effects of monthly administration of bromocriptine LAR is currently under progress to assess the long-term efficacy of this drug.

Adult↗
PubMed1991

Plasma catecholamine levels and lipid mobilization induced by yohimbine in obese and non-obese women.

Oral yohimbine administration (0.2 mg/kg) induced lipid mobilization (increase in plasma non-esterified fatty acids, NEFA) in fasting non-obese women (body mass index BMI = 20.2 +/- 0.5, age 35.5 +/- 2.7 years) without significant action on plasma glucose, insulin levels, heart rate or blood pressure during the time-course of the experiment (240 min). Plasma norpinephrine (but not epinephrine) concentrations were increased (100 percent) after oral yohimbine administration. Oral administration of propranolol (40 mg, 60 min before yohimbine) reduced the lipid-mobilizing action of yohimbine (70 percent) during the 60 min following its administration and then totally suppressed its effect until the end of the experimental period (180 min). In fasting obese women (BMI = 36.4 +/- 2.1, age 37 +/- 3.6 years), yohimbine provoked an increase in plasma NEFA levels which was not markedly different from that observed in non-obese subjects. It had no significant effect on plasma glucose, insulin levels, heart rate or blood pressure. Plasma norepinephrine increased in the same proportions. The lipid-mobilizing effect of yohimbine in women is mainly attributable to the increase in synaptic norepinephrine with a resultant increment in lipolysis by beta-adrenergic agonism. In the standard fasting conditions (12 hours) the blockade of the antilipolytic fat cell alpha 2-adrenoceptors seems to be a minor component of the lipomobilizing effect of yohimbine. Morever, when compared with non-obese women, the lipomobilizing effect of yohimbine is not enhanced in obese women.

Administration, Oral↗
PubMed1990

Bone mineral density and thyroid hormone therapy.

The purpose of this study was to evaluate prospectively the evolution of femoral and vertebral bone mineral density (BMD) in hypothyroid subjects treated with replacement doses (mean +/- SD dose of L-thyroxine = 135 +/- 32 micrograms/day) as compared to an untreated group. Vertebral bone density was also measured in other patients who had been treated for at least 2 years with either suppressive (mean dose = 154 +/- 36 micrograms/day, n = 28) or replacement doses (mean dose = 104 +/- 52 micrograms/day, n = 21) according to the thyrotrophin response (TSH) to the thyrotrophin releasing hormone (TRH) administration. In primary hypothyroid patients, a mean decrease of 5.4% (P less than 0.01) for vertebral BMD, 7.3% (P less than 0.01) for trochanter and 7% (P less than 0.001) for femoral neck was observed after 1 year of treatment. This loss was unrelated either to age or to menopausal status (ANOVA). A clinical and hormonal state of euthyroidism was reached since the 3rd month of treatment. Fasting urinary calcium/creatinine excretion was increased significantly (P less than 0.05) at the 3rd month, and plasma osteocalcin (OC) increased significantly from the 3rd month onwards (P less than 0.05) up to the 12th month (P less than 0.025). In the cross-sectional study, vertebral BMD was not significantly different from age-matched normal values in patients receiving either substitutive or suppressive doses of LT4. These results suggest that in the case of primary hypothyroidism even appropriate thyroid replacement therapy could lead during the first year of treatment to a significant reduction in vertebral and femoral BMD. However, the fact that an increased fracture rate has not been documented in long-term treated patients, and the results of our cross-sectional study, suggest that this bone mass reduction could be transient and reversible due to new bone formation at the end of the resorptive sequence.

Adult↗