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Biomedical subjects

G Turpin

Publications and source records attributed to G Turpin.

At least 19 recordsLinked to original sources
PubMed1992

The incidence of late-onset congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase deficiency among hirsute women.

OBJECTIVE: The present study was designed to determine the incidence of 3 beta-hydroxysteroid dehydrogenase deficiency (3 beta-HSD) in adult women with hyperandrogenism. DESIGN AND PATIENTS: In 78 hirsute patients and 30 normal women in the same age range, an ACTH stimulation test was performed on day 5 of the cycle by administration of a single bolus of 0.25 mg ACTH-(1-24) at 0800 h. MEASUREMENTS: The following steroids were measured before, 30 and 60 minutes after ACTH injection: delta 5-pregnenolone (delta 5-P), 17-hydroxy-delta 5-pregnenolone (17-OH delta 5-P), dehydroepiandrosterone (DHEA), delta 5-androstenediol, progesterone (P), 17-hydroxyprogesterone (17-OHP), androstenedione (A), testosterone (T) and cortisol. RESULTS: Maximum ACTH-stimulated values of delta 5-steroids were in excess of the 90% confidence limits of the control group in 19 hirsute women. Ten patients had an isolated increase in delta 5-P, 17-OH delta 5-P, DHEA or delta 5-androstenediol. Nine patients had an increase in two delta 5 steroids and none had increased values of three or four delta 5 steroids. The ratios of 17-OH delta 5-P to 17-OHP, DHEA to A, delta 5-P to P and delta 5-androstenediol to T were increased in 5, 1, 1 and 1 patients respectively. No patient had elevated values of more than one ratio. CONCLUSIONS: Using stringent diagnostic criteria, partial 3 beta-HSD deficiency was excluded in all 78 patients and therefore appears to be a rare disorder.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

[Mechanism of action of antilipemic drugs].

The study of the modes of action of lipid lowering drugs is important in order to evaluate their effects on the different lipid fractions and their possible secondary effects. These studies include: direct and indirect measurements of cholesterol absorption, the measurement of the principal enzymatic activities implicated in lipoprotein metabolism, especially those of lipases which play a fundamental role in the metabolism of particles rich in triglycerides and the inverse transport of cholesterol, and, finally, the measurement of intracellular enzyme activities. These last analyses are generally much more complex. Despite recent advances in all these investigative techniques, the mechanisms of action of many lipid lowering drugs remain obscure. Many have indirect modes of action like the inhibition of hydroxymethyl-glutaryl CoA by the fibrates and the mechanisms of action of the most recently introduced drugs are more complex than usually described. All these factors are important because the development of atherosclerosis depends on qualitative variations of the lipoproteins.

Arteriosclerosis↗
PubMed1991

A human TSH-secreting adenoma: endocrine, biochemical and morphological studies. Evidence of somatostatin receptors by using quantitative autoradiography. Clinical and biological improvement by SMS 201-995 treatment.

An invasive TSH-secreting adenoma inducing mild hyperthyroidism was diagnosed in a 16-year-old male. Initial surgical treatment led to a temporary clinical and biological improvement. Recurrence of the thyrotoxicosis was treated with the somatostatin analogue, SMS 201-995 (octreotide) with normalization of the serum thyroid hormone levels with a dose of 200 micrograms per day. With immunoelectron microscopy, the tumour cells appeared poorly granulated with small secretory granules located at the periphery of the cells; only part of those were immunoreactive with an anti-TSH beta monoclonal antibody. No specific TRH binding site was found in a tumour membrane preparation. By quantitative autoradiography, somatostatin specific binding sites were as numerous in the TSH-secreting tumour as in control GH-secreting tumours. Binding kinetics and guanosine triphosphate dependency of the binding were equivalent in the TSH and GH tumours tested. Although all of the tumour cells displayed the same ultrastructural features, some were non-immunoreactive, suggesting that they could secrete an altered form of TSH. The absence of TRH receptors in the tumour cells is in accordance with previous reports on this type of tumour. We confirm the efficiency of octreotide treatment in this case of neoplastic TSH inappropriate secretion. The therapeutic effect of octreotide goes along with the presence of a high density of guanine nucleotide-dependent somatostatin binding sites in the tumour cells.

Adenoma↗
PubMed1991

Cardiac hypertrophy and function in asymptomatic acromegaly.

Heart disease frequently occurs in advanced acromegaly. In order to investigate cardiac mass and function in acromegaly in the absence of obvious cardiac disease, we performed Doppler echocardiography in 15 asymptomatic acromegalic patients (six of them had systemic hypertension). The data were compared with those of a group of 10 age-matched controls. Left ventricular mass index (LVMI) was increased in acromegaly (110 +/- 32 vs 32 +/- 12 g m-2, P = 0.02), but shortening fraction and systolic time intervals did not differ. Mitral EF slope was decreased (80 +/- 21 vs 101 +/- 30 mms-1, P less than 0.02), while the duration of the isovolumic relaxation period (IRP) was increased (92 +/- 13 vs 69 +/- 16 ms, P less than 0.01). Hypertensive acromegalic patients (n = 6) had a higher LVMI than normotensive acromegalic patients (n = 9) (133 +/- 27 vs 94 +/- 24 g m-2, P = 0.02) and this was confirmed by a meta-analysis of data in the literature: the prevalence of hypertrophy was 76% in the presence of hypertension vs 50% in its absence, P less than 0.002. IRP was prolonged in normotensive acromegalic patients vs normal controls (90 +/- 11 vs 69 +/- 16 ms, P less than 0.01). In conclusion, subclinical cardiac abnormalities occur frequently in acromegaly in the absence of obvious heart disease, and hypertrophy is observed in asymptomatic hypertensive acromegaly. Moreover, diastolic abnormalities are found in asymptomatic acromegaly and could be caused by several heart-related factors.

Acromegaly↗
PubMed1990

Alterations in beta-adrenergic sensitivity and platelet alpha 2-adrenoceptors in obese women: effect of exercise and caloric restriction.

1. Peripheral adrenergic responses were studied in eight obese women before and after 15 days of caloric restriction (2500 kJ/day) and in eight sex- and age-matched lean controls. 2. beta-Adrenergic sensitivity (defined as the dose of isoprenaline required to increase resting heart rate by 25 beats/min) was evaluated before and after the diet. Density and affinity (determined as the apparent dissociation constant) of platelet alpha 2-adrenergic receptors, and plasma adrenaline and noradrenaline levels, were measured after overnight bed-rest and after 9 min of standardized exercise performed before and after the low caloric diet. 3. Before the diet basal antecubital venous plasma noradrenaline concentrations were lower in obese women when compared with lean women (0.94 +/- 0.06 vs 1.27 +/- 0.17 nmol/l, P less than 0.02). Isoprenaline sensitivity did not differ between lean and obese women. 4. At rest, platelet alpha 2-adrenoceptor density was lower in overweight than in lean women (129 +/- 21 vs 168 +/- 16 fmol/mg of protein, P less than 0.02). Exercise significantly increased platelet alpha 2-adrenoceptor density and decreased affinity in lean women. This decrease correlated with the rise in plasma noradrenaline. 5. In obese women exercise did not modify platelet alpha 2-adrenoceptor density or affinity, despite a significant increase in plasma catecholamines. However, the increase in plasma noradrenaline during exercise was lower in obese women. 6. The low caloric diet produced a beta-adrenergic supersensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

A LDL receptor gene homozygous mutation: PCR amplification, direct genomic sequencing, associated haplotype, rapid screening for frequency.

Many mutations in the LDL receptor (LDLR) gene have now been identified mostly as gross gene rearrangements, however they only represent a weak percentage of all deleterious gene mutations causing Familial Hypercholesterolemia (FH). This discrepancy may be related to the difficulties in characterizing point or small defective mutations. In a three-generation family with Familial Hypercholesterolemia, one specific haplotype constructed with 12 intragenic restriction fragment length polymorphisms (RFLP) cosegregated with the disease, while in the consanguineous propositus there was homozygosity for this haplotype. By polymerase chain reaction (PCR) amplification followed by direct sequencing there was unequivocal evidence for a double dose of a unique mutation, (namely a duplication of 4 bases in exon 17), while there was a single dose in heterozygote relatives. We consequently screened a population selected under clinical and geographical criteria for this mutation by PCR and allele specific oligonucleotides (ASO) hybridization. None of the 158 type IIa individuals tested carried the same mutation. Herein, is a rapid combined genetic and molecular approach to characterize and evaluate the frequency of LDL Receptor gene mutations causing Familial Hypercholesterolemia, towards targeted prevention and therapy.

Alleles↗
PubMed1990

[Role of arterial hypertension in the cardiac involvement of acromegaly].

Cardiac disease is common in acromegaly. Several mechanisms have been implicated: hypertension, coronary artery disease, valvular heart disease, endocrinopathies including "acromegalic cardiomyopathy". Fifteen consecutive patients with acromegaly, aged 48 +/- 13 years and treated for 4 +/- 5 years, underwent Doppler echocardiography. The patients had no cardiovascular symptoms: 6 had hypertension for 10 +/- 7 years and were compared with a group of 10 control subjects of the same age (48 +/- 17 years). The myocardial mass index (MMI) was higher in acromegaly (110 +/- 32 vs 82 +/- 12 g/m2, p = 0.02), left ventricular enddiastolic dimensions where comparable (48 +/- 7 vs 48 +/- 5 mm, NS) fractional shortening was slightly greater (0.37 +/- 0.04 vs 0.34 +/- 0.04, p = 0.07) as was velocity of shortening (NS) and the ratio of systolic time intervals (NS). The mitral EF slope was decreased (80 +/- 21 vs 101 +/- 30 ms; p less than 0.02); the ratio of the amplitudes of the E and A waves was a little decreased and the isovolumic relaxation phase was increased (92 +/- 13 vs 69 +/- 16 ms; p less than 0.01). Hypertensives (N = 6) had higher MMI (133 +/- 27 vs 94 +/- 24 g/m2, p = 0.02). Normotensive patients had larger isovolumic relaxation periods than control subjects (90 +/- 11 vs 69 +/- 16 ms, p less than 0.05). These results show that in the infraclinical phase, the heart in acromegaly is hypertrophied, not dilated. Hypertension plays a significant role in the development of this hypertrophy. Left ventricular systolic function is normal but diastolic function is impaired.

Acromegaly↗
PubMed1989

[Diets and drugs to lower blood cholesterol].

The scope of this paper is deliberately restricted to diets and drugs devised to lower blood cholesterol levels in pure hypercholesterolaemia (ex-type II in the international classification). This treatment is twofold: (1) Diets. In all cases except cardiovascular emergencies treatment should begin with a diet. If the subject is overweight, an overall low-calorie diet should be prescribed first. This will be followed by a diet with a low cholesterol and saturated fats content and a high polyunsaturated fats content, the latter including linoleic acid (C18:12) present in sunflower margarine and sunflower, maze and soya oils or eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) present in fatty fish. (2) Cholesterol-lowering drugs should then be prescribed if necessary. The most effective of these drugs are cholestyramine and fibrate derivatives. HMG CoA reductase inhibitors will shortly be available in France. This daily medicinal treatment should of course be uninterrupted, but it may be "reduced" in case of excellent therapeutic response.

Cholesterol↗
PubMed1989

Lack of effect in vivo of clofibrate on adrenal steroid secretion.

Clofibrate inhibits the synthesis of adrenal steroids when administered in vitro. In the present study the effect in vivo of clofibrate on adrenal steroid secretion has been investigated. Basal levels of plasma progesterone, corticosterone, aldosterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol, dehydroepiandrosterone sulphate and dehydroepiandrosterone, and their response to ACTH 1 mg im, were not reduced by chronic administration of clofibrate 2 g per day p.o. for 8 to 34 days to 6 hyperlipidaemic men.

17-alpha-Hydroxyprogesterone↗