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Biomedical subjects

G Turpin

Publications and source records attributed to G Turpin.

At least 37 records · Page 2Linked to original sources
PubMed1999

[LDL-apheresis therapy, methods and indications].

A SEVERE DISEASE: Homozygote hyper cholestrolemia is a very severe disease with an extremely high atherogenic potential. The risk of sudden death starts at about the age of 10 years and mortality reaches nearly 100% at 20 years. In this homozygote autosomal dominant disorder, serum cholesterol rises above 6 g/l due to a total deficiency of LDL-receptors. LDL-APHERESIS: The treatment of choice, LDL-apheresis, is an aggressive treatment. Drug regimens and palliative surgery have little or no effect. Liver transplantation is highly effective but compromises long term prognosis. LDL-apheresis, indicated in case of drug resistance, can be used to clear atherogenic LDL particles extracorporally. Currently it is the most effective means of lowering serum cholesterol in these patients and avoid potential cardiovascular complications. SEVERAL TECHNIQUES: The most specific techniques are also the most costly. These techniques allow treating whole blood or previously separated plasma. Such specific techniques are indicated in children. Compared with other European countries such as Germany, the development of these techniques has been retarded in France due to the lack of financing by the national health insurance system.

Blood Component Removal↗
PubMed1999

Effects of a low-calorie diet on resting metabolic rate and serum tri-iodothyronine levels in obese children.

UNLABELLED: The purpose of the study was to examine the effects of weight loss on resting metabolic rate (RMR) and on serum T3 levels in obese children and to investigate whether RMR changes are related to T3 changes. Sixty-four healthy, overweight, children (age: 12.1+/-1.1 years, body mass index 29.3+/-4.3 kg/m2) were studied during a 6-week weight reduction programme. RMR (by indirect calorimetry) total T3, total T4, TSH and fat-free mass (FFM) (by anthropometry) were measured at baseline and after 6 weeks of dietary treatment. Weight loss resulted in a 10.1% decline in RMR (P < 0.01) and a 23.4% decrease in serum T3 levels (P < 0.001). RMR was correlated with FFM before (r = 0.78, P < 0.001) and after weight loss (r = 0.76, P < 0.001). The changes in RMR were positively correlated with the changes in FFM (r = 0.48, P < 0.05) but also with the changes in serum T3 levels (r = 0.47, P < 0.05). The initial T3 levels predicted the subsequent fall in T3 that occurred after 6 weeks of dietary treatment (r = -0.60, P < 0.001). CONCLUSIONS: A significant decrease in serum T3 concentrations and resting metabolic rate occurred as a result of a 6-week weight reduction programme in an obese child population. The decline in T3 levels combined with fat-free mass loss could be responsible for the reduction in resting metabolic rate.

Adolescent↗
PubMed1999

Cysteine is a cardiovascular risk factor in hyperlipidemic patients.

Several studies have reported that moderate hyperhomocysteinemia is related to an increased risk for atherosclerosis, but few data are available with regard to any other thiol compound having a potential vascular toxicity. Therefore, we measured both total cysteine and homocysteine plasma levels in patients with hyperlipidemia (242 males and 147 females, 41-65 years old). Homocysteine was higher in males than in females, 13.2+/-4.1 versus 11.1+/-3.4 micromol/l (P<0.0001). The mean cysteine level was 243.3+/-45.7 micromol/l in the whole study population. The subjects were split in two groups, symptomatic patients with cardiovascular disease (n = 106) and asymptomatic subjects (n = 283). Blood pressure, smoking status, total cholesterol, LDL-cholesterol and triglycerides did not statistically differ between groups, but the mean HDL-cholesterol level was lower in symptomatic patients (1.24+/-0.38 versus 1.42+/-0.41, P<0.0001). Cysteine levels were higher in patients with cardiovascular disease than in asymptomatic patients, respectively 254.7+/-47.7 versus 239.1+/-44.3 micromol/l (P = 0.003). A similar result was found for homocysteine, respectively 13.1+/-4.3 versus 12.2+/-3.9 micromol/l (P = 0.05). To analyse whether cysteine levels were related to atherosclerosis independently of age, adjusted levels were compared between asymptomatic patients with normal carotid arteries (n = 176), carotid atherosclerosis (n = 107) and symptomatic patients (n = 106). Age adjusted cysteine levels differed significantly between groups (P = 0.027) while the P-value was of borderline significance for homocysteine (P = 0.09). Odds ratios for having symptomatic cardiovascular disease were 1.81 (95% CI, 1.02-3.21) and 2.05 (95% CI, 1.16-3.60) for the mid and highest tertiles of cysteine using the lowest as the reference. After adjustment in a multivariate model including age, sex, and creatinine, the odds ratio for disease remained significant between the highest tertile versus the lowest (OR = 1.89). Adjusted odds ratios were found to be weaker when homocysteine tertiles were compared. Our data suggest that plasma total cysteine is a risk factor for atherosclerosis in hyperlipidemic patients.

Adult↗
PubMed1999

Interrelationships between postprandial lipoprotein B:CIII particle changes and high-density lipoprotein subpopulation profiles in mixed hyperlipoproteinemia.

We studied the relationships postprandially between triglyceride-rich lipoprotein (TRL) and high-density lipoprotein (HDL) in 11 mixed hyperlipoproteinemia (MHL) and 11 hypercholesterolemia (HCL) patients. The high and prolonged postprandial triglyceridemia response observed in MHL but not HCL patients was essentially dependent on very-low-density lipoprotein (VLDL) changes. This abnormal response was related to decreased lipoprotein lipase (LPL) activity (-48.7%, P<.01) in MHL compared with HCL subjects. Cholesteryl ester transfer protein (CETP) activity was postprandially enhanced only in MHL patients, and this elevation persisted in the late period (+19% at 12 hours, P<.05), sustaining the delayed enrichment of VLDL with cholesteryl ester (CE). The late postprandial period in MHL patients was also characterized by high levels of apolipoprotein B (apoB)-containing lipoproteins with apoCIII ([LpB:CIII] +36% at 12 hours, P<.01) and decreased levels of apoCIII contained in HDL ([LpCIII-HDL] -34% at 12 hours, P<.01), reflecting probably a defective return of apoCIII from TRL toward HDL. In MHL compared with HCL patients, decreased HDL2 levels were related to both HDL2b and HDL2a subpopulations (-57% and -49%, respectively, P<.01 for both) and decreased apoA-I levels (-53%, P<.01) were equally linked to decreased HDL2 with apoA-I only (LpA-I) and HDL2 with both apoA-I and apoA-II ([LpA-I:A-II] -55% and -52%, respectively, P<.01 for both). The significant inverse correlations between the postprandial magnitude of LpB:CIII and HDL2-LpA-I and HDL2b levels in MHL patients underline the close TRL-HDL interrelationships. Our findings indicate that TRL and HDL abnormalities evidenced at fasting were postprandially amplified, tightly interrelated, and persistent during the late fed period in mixed hyperlipidemia. Thus, these fasting abnormalities are likely postprandially originated and may constitute proatherogenic lipoprotein disorders additional to the HCL in MHL patients.

Adult↗
PubMed1999

Relationship between thyroid hormones and fibrinogen levels.

Hypothyroid patients may have several haemostatic abnormalities such as modification of the coagulation proteins and a bleeding tendency. However, conflicting data have been reported, although in some reports, the groups of patients studied were small. We previously reported in a large population that plasma D-dimers and free thyroxine (FT4) levels were inversely correlated. Since D-dimers are also associated with fibrinogen levels, we analysed the relationship between fibrinogen and FT4 levels. The population consisted of 959 patients (61% men and 39% women), 28% of whom were current smokers. We showed that fibrinogen and FT4 levels were inversely correlated (r = -0.12, P = 0.0001) in the overall population, in the non-smoker subgroup (r = -0.13, P = 0.0007) and in the subgroup of patients with strictly normal FT4 levels (r = -0.11, P = 0.0006). The relationship between FT4 and fibrinogen levels was independent of age, sex and smoking habits. Furthermore, there was a significant difference between the mean fibrinogen levels in the patients in the lowest FT4 subgroup and those in the highest FT4 subgroup, which was similar to the difference previously observed in patients with or without evidence of atherosclerotic disease in epidemiological studies. In conclusion, we found a negative and independent relationship between fibrinogen and FT4. These results are consistent with our previous findings of a tendency to a more coagulable state in patients with normal-low FT4 levels compared with those with normal-high FT4 levels.

Adult↗
PubMed1999

Low free-thyroxine levels are a risk factor for subclinical atherosclerosis in euthyroid hyperlipidemic patients.

BACKGROUND: Patients displaying overt and subclinical hypothyroidism have more cardiovascular risk factors. Consequently, they are more likely to develop atherosclerosis and cardiovascular diseases. OBJECTIVE: To analyze whether low free-thyroxine levels (FTL) would also be associated with atherosclerosis in euthyroid patients. METHODS: We selected a group of 1434 healthy euthyroid male patients without known histories of thyroid disease and with levels of thyroid-stimulating hormone values within the normal range (mean 1.70+/-0.76 mUl/l, range 0.13-4.01 mUl/l). Mean age of these patients who had been referred for assessment of hyperlipidemia was 44.6 years and mean FTL was 14.25+/-3.06 pmol/l. We divided the population according to the degree of atherosclerosis in the carotid arteries. RESULTS: Mean age, body mass index, systolic blood pressure, cigarettes/day, blood level of glucose, cholesterol levels, and fibrinogen levels were significantly higher for the patients with atherosclerotic lesions whereas mean FTL was lower for patients with carotid atherosclerosis (P = 0.0002). The relationship between FTL and carotid atherosclerosis was independent from the following cardiovascular risk factors: age, hypertension, amount of excess weight, cholesterol level, fibrinogen level, smoking status, and presence versus absence of diabetes mellitus. CONCLUSIONS: Low FTL is a risk factor for atherosclerosis in male euthyroid hyperlipidemic patients.

Adult↗
PubMed1999

Indications and limits of ultrasound-guided cytology in the management of nonpalpable thyroid nodules.

Although ultrasound (US)-guided fine needle aspiration biopsy (FNAB) is widely prescribed in nonpalpable thyroid nodules, the goal of this study was to define precisely the indications and limits of US-FNAB in a series of 450 nonpalpable nodules. Among 94 surgically controlled cases, 20 (8 infracentimetric and 12 centimetric or supracentimetric) carcinomas were diagnosed. The diagnosis of malignancy was successfully made by US-FNAB in 16 of 20 carcinomas, 3 were missed because of insufficient cytological material, and 1 was misdiagnosed. US-FNAB sensitivity and specificity were 94% and 63%, respectively. A logistic model indicated that nodule size (P < 0.6) was not associated with histological diagnosis, but that solid hypoechoic features were more likely to be malignant (P < 0.0003), with US sensitivity and specificity for malignancy of 80% and 70%, respectively. Logistic regression indicated that adequate cytological material significantly increased with nodule size (P < 0.0001). This result outlined the limits of US-FNAB in small nodules. Hence, indication of US-FNAB appears judicious in centimetric or supracentimetric nodules or in solid and hypoechoic ones. Such a management would allow the discovery of 15 of 20 carcinomas and would avoid 16% of unnecessary biopsies.

Adolescent↗
PubMed1999

Effects of stimulus intensity, risetime, and duration on autonomic and behavioral responding: implications for the differentiation of orienting, startle, and defense responses.

The effects of stimulus intensity, duration, and risetime on the autonomic and behavioral components of orienting, startle, and defense responses were investigated. Six groups of 10 students were presented with 15 white noise stimuli at either 60 or 100 dB, with controlled risetimes of either 5 or 200 ms, and at stimulus durations of 1 or 5 s (1 s only in the case of the 60-dB groups). A dishabituation stimulus consisting of a 1000 Hz tone was also presented. Measures consisted of skin conductance and heart rate, together with ratings of facial expressions and upper torso movement obtained using video recording. Increased intensity resulted in greater amplitudes and frequencies of electrodermal and behavioral responses, and a change from cardiac deceleration to acceleration. Faster risetimes elicited larger electrodermal responses, greater frequencies of eye-blinks, head and body movements, and larger cardiac accelerations. The effects of duration for the 100-dB stimuli were less clear-cut. Overall, the results are discussed in relation to the differentiation of orienting, startle, and defense responses.

Acoustic Stimulation↗
PubMed1999

[Prognostic factors in the surgical management of acromegaly].

To determine the prognostic factors of surgical cure of growth hormone secreting pituitary adenomas, we have studied 48 patients operated between 1982 and 1992. We compared the features of the cured group (n = 18) with the non cured group (n = 30). We found that the factors of poor prognostic were: young age, growth hormone level before surgery over 50 ng/ml, invasive adenomas, monohormonal status in immunocytochemistry, and lack of decrease in postoperative growth hormone level during the glucose tolerance test.

Acromegaly↗
PubMed1999

Secondary thyroidectomy in patients with prior thyroid surgery for benign disease: a study of 203 cases.

BACKGROUND: The goal of this study was to evaluate the complication rate of secondary thyroidectomy in patients with prior thyroid surgery for benign disease. METHODS: Over an 8-year period, 203 thyroid reoperations were performed on 202 patients. All information relating to operative procedures, pathology, and complications was recorded prospectively. RESULTS: There were 24 men and 178 women with a mean age of 52 years. Prior surgery was unilateral in 136 cases (67%) and bilateral in 67 cases (33%), and 14 patients (6.9%) had more than 1 previous thyroid operation. For euthyroid or pretoxic recurrent nodular goiter, 190 reoperations were performed and 13 reoperations were performed for recurrent thyrotoxicosis. Twenty-three cancers were found in a specimen (11.4%). Completion thyroidectomy was done in 143 patients. Postoperative complications occurred in 21 patients (10.4%): recurrent laryngeal nerve palsy (7 patients), hypocalcemia (8 patients), hematoma requiring surgical evacuation (5 patients), and wound infection (1 patient). Complications remained permanent in 4 patients (2%). CONCLUSIONS: The permanent complication rate is higher in thyroid reoperations than in primary thyroid operations. However, we believe that this 2% rate is low enough to allow reoperation whenever it is necessary, provided precise operative rules are respected.

Adult↗
PubMed1999

[Familial hypercholesterolemia].

Familial hypercholesterolemia is characterized by a high plasma LDL-cholesterol level. The low-density particles are the end-product of the triglyceride-rich particles, i.e. VLDL, synthetized by the liver. These triglyceride-rich particles are subsequently transformed into intermediate density lipoprotein by the lipoprotein lipase and LDL after further triglyceride hydrolysis by the hepatic lipase. The LDL particles are taken up in all cells by the mean of the LDL receptor. A large body of evidence (including experimental, clinical, epidemiological data as well as the results of large trial with lipid lowering drugs) has accumulated to establish that these particles are one of the major causative factor of atherosclerosis and its complications. Two different mechanisms may be at work in the familial hypercholesterolemia: a mutation in the LDL receptor or a single mutation in the apolipoprotein B100. Specific therapeutic intervention should be undertaken to decrease the risk to develop cardiovascular disease, mainly coronary heart disease. The therapeutic intervention includes both a diet low in saturated fatty acids and cholesterol and statins which are now the first line therapy. Fibrates are proposed to those who do not tolerate statins and LDL-apheresis is associated to statin in the rare homozygous familial hypercholesterolemia.

Anticholesteremic Agents↗
PubMed1999

Modifications of alpha-tocopherol and fatty acid concentrations in blood and adipose tissue of obese patients during a weight loss programme.

BACKGROUND AND AIM: The aim of the study was to describe qualitative and/or quantitative modifications of lipoproteins, including their fatty acid composition, in obese patients during a hypocaloric diet, and determine whether the variations observed paralleled modifications of alpha-tocopherol concentration in adipose tissue and blood. METHODS AND RESULTS: 15 healthy, obese volunteers (5 males, 10 females; age: 32-69 yr; BMI: 28.4-60.5 kg/m2) were given a 3-week hypocaloric diet (3.9 MJ (941 kcal)). Adipose tissue and blood samples were taken at the beginning and at the end of this period. At baseline and after 3 weeks measurements were made for alpha-tocopherol and fatty acids in total serum, lipoproteins and adipose tissue; thiobarbituric acid-reactive substances (TBARS) in serum. A significant drop in cholesterol-rich particles (LDL and HDL) was observed, in parallel to a significant enrichment of n-6 polyunsaturated fatty acids (PUFA) at the expense of both saturated and monounsaturated fatty acids in serum. A drop in alpha-tocopherol concentration (expressed as mumol alpha-tocopherol/g lipid) in serum and lipoprotein fractions paralleled the decrease in cholesterol-rich lipoproteins. CONCLUSIONS: Our results suggest that a hypocaloric diet not only decreases cholesterol-rich particle levels in serum, but also leads to a significant modification of fatty acid composition which may reflect improvement of insulin sensitivity. We did not observe any modification in adipose tissue after diet with regard to both alpha-tocopherol and fatty acid concentrations. Despite a drop in alpha-tocopherol concentration and an increase in n-6 PUFA content in serum, we did not find any enhancement of serum lipid peroxidation level evaluated by the thiobarbituric acid-reactive substance (TBARS) assay. If we assume that dietary intakes of alpha-tocopherol were not modified during this diet, it can be supposed that adipose tissue released alpha-tocopherol without any specific regulation, in parallel to the release of fatty acids.

Adipose Tissue↗
PubMed1998

[Lipids/hemostasis interactions. A new approach to cardiovascular risk factors].

NEW CARDIOVASCULAR RISK FACTORS: A causal link would appear to exist between hemostasis and cardiovascular disease. This is particularly true for fibrinogen which is an independent risk factor. MULTIPLE INTERACTIONS: There is an association between elevated triglyceride and FVIIc (pro-coagulant) levels and hypofibrinolytic PAI-1. In addition, an association exists between elevated cholesterol and FVIIc and platelet activation. LIPID LOWERING DRUGS AFFECT HEMOSTASIS: The hemostasis equilibrium is modulated by diet. In addition, fibrinogen levels are lowered by fibrates and platelet activation and thrombin generation are decreased by statins. These modifications have a potential clinical interest. Such observations remain to be confirmed by cardiovascular prevention studies with the specific objective of evaluating the effect of lipid lowering drugs on hemostasis parameters.

Blood Coagulation Factors↗
PubMed1998

Characterization of two HDL subfractions and LpA-I, LpA-I:A-II distribution profiles and clinical characteristics of hyperalphalipoproteinemic subjects without cholesterol ester transfer protein deficiency.

The aims of the present study were (i) to characterize the HDL2, HDL3 and the LpA-I, LpA-I:A-II distribution, (ii) to investigate the prevalence of atherosclerotic lesions and (iii) to assess the activity of cholesteryl ester transfer protein (CETP) in 29 hyperalphalipoproteinemic (HALP) patients (HDL-C=90+/-11 mg/dl) with combined hypercholesterolemia (LDL-C=180+/-16 mg/dl). According to the HDL2/HDL3 and LpA-I/LpA-I:A-II ratios, two HALP profiles (A and B) were defined: in 22 patients (HALP profile A) these ratios were increased compared to the normolipidemic control subjects (1.19+/-0.11 versus 0.53+/-0.19, P < 0.001 and 1.01+/-0.2 versus 0.51+/-0.25, P < 0.001, respectively) and in seven patients (HALP profile B) these ratios were within the normal range (0.64+/-0.20 and 0.69+/-0.2, respectively). The atherosclerotic lesions were assessed by ultrasonography of the carotid arteries. Amongst patients with HALP profile A, 17 were free from lesions, five had intimal wall thickening and none displayed plaques, whereas for patients within the HALP profile B, only one was free from lesions, two had intimal wall thickening and four displayed plaques. CETP activities (348+/-116 versus 371+/-75%/ml/h) and CETP concentrations (2.4+/-0.5 versus 2.5+/-0.6 microg/ml) were similar in HALP profiles A and B, however these values were both higher than in control subjects (190+/-40%/ml/h, P < 0.001 and 1.8+/-0.3 microg/ml, P < 0.001, respectively). Hence the hyperalphalipoproteinemic profiles (A and B) described here were not related to CETP deficiency. In conclusion, the HALP profile A was characterized by both increased HDL2/HDL3 and LpA-I/LpA-I:A-II ratios and was associated with a low prevalence of atherosclerosis, whereas the HALP profile B, characterized by HDL2/HDL3 and LpA-I/LpA-I:A-II ratios within the normal range, was less cardioprotective.

Adult↗
PubMed1998

Hyperalphalipoproteinemia: characterization of a cardioprotective profile associating increased high-density lipoprotein2 levels and decreased hepatic lipase activity.

The aim of the present study was to investigate the high-density lipoprotein (HDL) structural characteristics and metabolism in hyperalphalipoproteinemic (HALP) patients (HDL-cholesterol [HDL-C], 92 +/- 14 mg/dL) with combined elevated low-density lipoprotein-cholesterol (LDL-C) levels (LDL-C, 181 +/- 33 mg/dL). Patients were subjected to a complete cardiovascular examination, including ultrasonographic investigation of carotid arteries. Two HALP profiles were identified according to the HDL2/HDL3 ratio. HALP profile A was characterized in 28 patients by increased HDL2/HDL3 ratio, HDL2b, and lipoprotein (Lp)A-I levels compared with normolipidemic subjects, and HALP profile B, including the 12 remaining patients, was characterized by a HDL2/HDL3 ratio within the normal range and by the increase of all HDL subclasses (HDL(2b,2a,3a,3b,3c)), LpA-I, and LpA-I:A-II levels. With regard to the exploration of carotid arteries, in HALP profile A, 20 patients were free from lesions and eight had only intimal wall thickening. In HALP profile B, only one patient was free from lesions, four had intimal wall thickening, and seven displayed plaques, but none had stenosis. Taking into account the number of patients with plaques within each group, HALP profile A was associated with a low prevalence of atherosclerotic lesions, whereas HALP profile B was less cardioprotective (odds ratio, 77.7 [95% confidence interval, 3.7 to 1,569.7]; P < .0001). For both HALP profiles, cholesteryl ester transfer protein (CETP) deficiency was discarded and activities of phospholipid transfer protein (PLTP) and lipoprotein lipase (LPL) were normal. However, hepatic lipase (HL) activity was significantly decreased in HALP profile A, but within the normal range for HALP profile B. In conclusion, an HALP profile A with a low prevalence of atherosclerosis was characterized by an increased HDL2/HDL3 ratio, HDL2b, and LpA-I levels associated with decreased HL activity.

Adult↗
PubMed1998

Sheehan's syndrome: differential diagnosis in the acute phase.

Many studies have been done in the later course of Sheehan's syndrome, but very few have documented the acute phase with clinical, endocrine and imaging data. We present the case of a young woman complaining of severe headache after delivery, who developed hypopituitarism. Magnetic resonance imaging (MRI) disclosed the presence of an enlarged non haemorrhagic pituitary gland. Follow-up MRI showed a spontaneous and rapid shrinkage of the pituitary, within 20 days, which appeared as an empty sella 3 months later. Sheehan's syndrome may initially closely mimic hypophysitis, or the necrosis of an adenoma. We discuss the differential diagnoses, important for the best therapeutic management.

Acute Disease↗
PubMed1998

Prevalence of lymphocytic infiltrate in 1400 pituitary adenomas.

To evaluate the prevalence of lymphocytic infiltrate in a large series of pituitary adenomas, we retrospectively studied tumor tissues from 1400 patients. Based on immunocytochemical data, tumors were classified as PRL (n=411), multihormonal (n=310), immunonegative (n=275), ACTH (n=166), GH (n=137), alpha subunit (n=44), FSH and/or LH, (n=42), and TSH (n=15) adenomas. The lymphocytic infiltrate was diagnosed on histological examination and investigated by immunostaining with anti LCA (human leucocyte common antigen), anti CD45RO (human T cell) and anti CD20 (human B cell) antibodies. Lymphocytic infiltrate was present in 40 adenomas (2.9%), 26 females and 14 males, aged 18 to 77 years (mean+/-SD, 37+/-14 years). The tumors were 19 PRL, 8 multihormonal, 4 GH, 4 alpha subunit, 3 ACTH, and 2 immunonegative adenomas. In PRL adenomas, the sex ratio (female/male) and the age were similar in patients with and without lymphocytic infiltrate (2.8 vs. 4.6 and 29+/-6 years vs. 32+/-11 years, respectively). The frequency of lymphocytic infiltrate was similar in PRL, GH, ACTH and multihormonal adenomas, but lymphocytic infiltrate was significantly more frequent in PRL adenoma than in immunonegative adenoma, and in alpha subunit adenoma than in immunonegative, ACTH and multihormonal adenomas. The lymphocytic cells were almost exclusively T cells. We conclude that lymphocytic infiltrates are rare in pituitary adenomas. Their frequency is not statistically different in major categories of secreting adenomas (PRL, GH, ACTH, multihormonal). Their pathophysiological significance remains to be established.

Adenoma↗