Intrinsic toroidal rotation, density peaking, and turbulence regimes in the core of tokamak plasmas.

Observations in the ASDEX Upgrade tokamak show a correlation between the gradient of the intrinsic toroidal rotation profile and the logarithmic gradient of the electron density profile. The intrinsic toroidal rotation in the center of the plasma reverses from co- to countercurrent when the logarithmic density gradients are large, and the turbulence is either dominated by trapped electron modes or is at the transition between ion temperature gradient and trapped electron modes. A study based on local gyrokinetic calculations suggests that the dominant trend in the observations can be explained by the combination of residual stresses produced by E × B and profile shearing mechanisms.

Experimental evidence of momentum transport induced by an up-down asymmetric magnetic equilibrium in toroidal plasmas.

The first experimental evidence of parallel momentum transport generated by the up-down asymmetry of a toroidal plasma is reported. The experiments, conducted in the Tokamak à Configuration Variable, were motivated by the recent theoretical discovery of ion-scale turbulent momentum transport induced by an up-down asymmetry in the magnetic equilibrium. The toroidal rotation gradient is observed to depend on the asymmetry in the outer part of the plasma leading to a variation of the central rotation by a factor of 1.5-2. The direction of the effect and its magnitude are in agreement with theoretical predictions for the eight possible combinations of plasma asymmetry, current, and magnetic field.

Genetic variation in RYR1 and malignant hyperthermia phenotypes.

BACKGROUND: Malignant hyperthermia (MH) is associated, in the majority of cases, with mutations in RYR1, the gene encoding the skeletal muscle ryanodine receptor. Our primary aim was to assess whether different RYR1 variants are associated with quantitative differences in MH phenotype. METHODS: The degree of in vitro pharmacological muscle contracture response and the baseline serum creatine kinase (CK) concentration were used to generate a series of quantitative phenotypes for MH. We then undertook the most extensive RYR1 genotype-phenotype correlation in MH to date using 504 individuals from 204 MH families and 23 RYR1 variants. We also determined the association between a clinical phenotype and both the laboratory phenotype and RYR1 genotype. RESULTS: We report a novel correlation between the degree of in vitro pharmacological muscle contracture responses and the onset time of the clinical MH response in index cases (P<0.05). There was also a significant correlation between baseline CK concentration and clinical onset time (P=0.039). The specific RYR1 variant was a significant determinant of the severity of each laboratory phenotype (P<0.0001). CONCLUSIONS: The MH phenotype differs significantly with different RYR1 variants. Variants leading to more severe MH phenotype are distributed throughout the gene and tend to lie at relatively conserved sites in the protein. Differences in phenotype severity between RYR1 variants may explain the variability in clinical penetrance of MH during anaesthesia and why some variants have been associated with exercise-induced rhabdomyolysis and heat stroke. They may also inform a mutation screening strategy in cases of idiopathic hyperCKaemia.

Transport of parallel momentum induced by current-symmetry breaking in toroidal plasmas.

The symmetry of a physical system strongly impacts on its properties. In toroidal plasmas, the symmetry along a magnetic field line usually constrains the radial flux of parallel momentum to zero in the absence of background flows. By breaking the up-down symmetry of the toroidal currents, this constraint can be relaxed. The parallel asymmetry in the magnetic configuration then leads to an incomplete cancellation of the turbulent momentum flux across a flux surface. The magnitude of the subsequent toroidal rotation increases with the up-down asymmetry and its sign depends on the direction of the toroidal magnetic field and plasma current. Such a mechanism offers new insights in the interpretation and control of the intrinsic toroidal rotation in present day experiments.

[Bone mineral density and biological markers of bone repair in patients with adrenal incidentaloma: effect of subclinical hypercortisolism]. / Densité minérale osseuse et marqueurs biologiques de remaniement osseux chez des patients porteurs d'incidentalome surrénalien: effet d'un hypercortisolisme infraclinique.

PURPOSE: Some adrenal incidentalomas produce cortisol in mild excess ('subclinical' Cushing's adenomas) and can potentially induce osteopenia. Their diagnosis is usually based on exclusive tumour uptake on adrenal scintigraphy using 131I-6 beta-methyl-iodo-19-norcholesterol and on inadequate cortisol response to dexamethasone (DXM) suppression tests. The aims of the present study were to evaluate bone mineral density (BMD) and metabolic markers of bone turnover in patients with incidentalomas and to test the effect of mild hypercortisolism on bone parameters. METHODS: Thirty-five patients (13 men, 22 postmenopausal women, 49-76 years) with unilateral incidentaloma were studied. BMD was measured by dual X-ray absorptiometry. Two biochemical markers of bone formation, serum osteocalcin (BGP) and bone alkaline phosphatase (bALP), and two markers of bone resorption, urinary free deoxypyridinoline (D-Pyr) and urinary carboxy-telopeptide of bone type 1 collagen (CTX), were measured by radioimmunoassay. D-Pyr and CTX were corrected for creatinine excretion. RESULTS: Median values of lumbar and femoral T-score were -1.125 and -0.920, respectively, whereas corresponding Z-score values where normal (0.105 and 0.120, respectively). Thirty-nine percent of patients had low serum BGP values and 3% had low bALP values; 16% showed elevated D-Pyr/creatinine values and 23% increased CTX/creatinine values. Patients both with suppression of the contralateral adrenal on scintigraphy and with an inadequate cortisol response to 1 mg DXM (> 50 nmol/L) (n = 14) presented a lower femoral T-score (P < 0.02) and, to a lesser extent, a lower femoral Z-score (P = 0.11) than other patients (n = 21). The proportion of increased values of CTX/creatinine (42% versus 11%, P = 0.08) also tended to be higher in the first than in the second group of patients. These two groups of patients were similar in terms of age, but tumour size was larger (P < 0.04) and plasma ACTH value was lower (P < 0.02) in patients with scintigraphic and endocrine abnormalities. CONCLUSION: Subclinical hypercortisolism defined on the basis of scintigraphic and hormonal criteria seems to contribute to bone loss in patients with adrenal incidentaloma. As other possible side effects of mild hypercortisolism, these findings have to be taken into account in the therapeutic management of these patients.

Body composition, fasting leptin, and sex steroid administration determine GH sensitivity in peripubertal short children.

Serum IGF-I levels in GH-treated subjects demonstrate a wide range of responsiveness to GH. However, the factors influencing GH sensitivity are not well known. The aim of this work was 1) to test whether body composition (determined by dual energy x-ray absorptiometry) or factors related to body composition (fasting blood glucose, FFA, C-peptide, leptin, and insulin sensitivity determined by an insulin tolerance test) influence GH sensitivity; and 2) to study the effect of sex steroid priming on GH sensitivity. We measured serum IGF-I at baseline and 24 h after a single administration of GH (2 mg/m(2)) in 60 healthy prepubertal and early pubertal children (height, -2.1 +/- 1.0 SD score). GH sensitivity, as estimated by the increase in serum IGF-I after GH administration (difference between stimulated and baseline serum IGF-I = delta IGF-I), was also determined after a short-term administration of oral ethinyl E2 in girls and im T in boys. The serum IGF-I concentration was 297 +/- 114 microg/liter at baseline and increased to 429 +/- 160 microg/liter, corresponding to a 46 +/- 29% increase over the baseline value (P < 0.0001, stimulated vs. baseline serum IGF-I). delta IGF-I was not different between gender or pubertal stage. There were positive correlations (P < 0.001) between delta IGF-I and adiposity (total body fat, r = 0.62; trunk fat, r = 0.62), fasting leptin (r = 0.64), and C-peptide (r = 0.54), and a negative correlation with fasting FFA (r = -0.33; P < 0.05) even after adjustment for age, gender, and pubertal stage. These factors remained significant independent predictors of the absolute as well as the percent increase in serum IGF-I in multiple regression analyses. Priming with T and ethinyl E2 had a similar stimulating effect on the serum GH peak in response to the insulin tolerance test. In boys, serum baseline IGF-I increased by 60%, and delta IGF-I was similar after vs. before T administration. By contrast, in girls, serum baseline IGF-I was similar, and delta IGF-I was 60% less after vs. before ethinyl E2 administration. This study indicates that 1) GH sensitivity is determined by fat mass, serum fasting leptin, C-peptide, and FFA; and 2) oral ethinyl E2 and im T have divergent effects on the IGF-I response to a single administration of GH.

Relationships between placental GH concentration and maternal smoking, newborn gender, and maternal leptin: possible implications for birth weight.

The control of fetal growth depends on multiple hormones, including both IGF-I and placental GH (PGH) in the mother, and IGF-I rather than pituitary GH (pitGH) in the fetus. Leptin, which is produced by adipocytes and syncitiotrophoblast cells, has also been thought to influence fetal growth by an as yet unknown mechanism. This study assessed the relationships between the GH-IGF-I axis in mothers and newborns, and maternal smoking, neonate gender, and maternal and fetal leptin. We collected blood in 87 mothers at the onset of labor and cord blood immediately after birth in their 87 healthy full-term newborns. GH concentrations were log(10) transformed, and data were expressed as the geometric mean (-1, +1 tolerance factor). PGH was lower in the 30 smoking mothers, as compared with the 57 nonsmoking mothers [18.2 (11.5; 28.6) vs. 27.0 (15.1; 48.2) microg/liter, P < 0.01]. Cord blood IGF-I was lower in neonates from smoking mothers (90 +/- 44 vs. 135 +/- 65 microg/liter, mean +/- SD, P < 0.01), consistent with their lower birth weight percentile (P < 0.01). A gender effect was observed for PGH, which was higher when the newborn was female, and for newborn pitGH and newborn leptin, which were, respectively, lower and higher in females, even after adjustment for birth weight and maternal smoking category (P < 0.05 for all comparisons). Multiple regression analyses identified maternal leptin as a negative predictor of PGH (P < 0.05) and newborn leptin as a positive predictor of newborn IGF-I (P < 0.05). Maternal smoking is associated to decreased maternal PGH and cord blood IGF-I concentrations. A sexual dimorphism for PGH, newborn pitGH, and newborn leptin exists at the time of birth, but its physiological significance remains to be studied. The relationships between maternal leptin and PGH and between cord blood leptin and IGF-I are consistent with the hypothesis that leptin could contribute to the control of fetal growth.

Osteoporosis in men: a potential role for the sex hormone binding globulin.

The exact mechanism of bone loss remains unknown in primary male osteoporosis. It has been suggested that estrogen and sex hormone binding globulin (SHBG) play a role in regulating bone turnover and bone mass in healthy men > 65 years of age. In the present study, 80 men (mean age 49.7 years) with bone mineral density >2.5 SD below the young adult value and 40 age-matched controls were recruited to evaluate the relationships between sex hormone levels, bone biochemical markers levels, and bone mineral density. Fasting serum samples were assayed for total and free testosterone total estradiol, and SHBG. The free androgen index, was calculated as: [total testosterone/SHBG * 100]. Bone remodeling was evaluated by measurement of urinary levels of the C-telopeptide of type I collagen (CTx) and free deoxypyridinoline (D-Pyr), serum osteocalcin, and bone-specific alkaline phosphatase (bSAP). There was no significant difference between controls and osteoporotic men according to age, body mass index (BMI), total testosterone, and estradiol. In contrast, serum SHBG level was significantly higher (+42.2%), whereas free androgen index was lower (-24.8%) in patients with primary or secondary osteoporosis. Testosterone and estradiol levels did not correlate with any bone resorption or bone formation markers. In contrast, stepwise linear regression analysis showed that SHBG was significantly correlated with D-Pyr (r = 0.45, p < 0.05) and CTx (r = 0.34, p < 0.05) in primary osteoporosis. In secondary osteoporosis, SHBG was correlated with D-Pyr (r = 0.48, p < 0.05) and bSAP (r = 0.55, p < 0.01). After adjustment for age and BMI, hip bone mineral density (BMD) was not associated with testosterone or estradiol but only with serum SHBG (r = -0.33, p < 0.01) in primary osteoporosis. The same relationship was observed in men with secondary osteoporosis (r = -0.34, p < 0.01). Among osteoporotic patients, spinal radiography showed at least one vertebral crush fracture in 36 men and none in 44. Serum SHBG concentration was significantly associated with the presence of vertebral fracture: the odds ratio was 2.0 (95% confidence interval [CI] 1.2-3.5) for an increase of one standard deviation of SHBG. In conclusion, the present study showed that serum SHBG concentration is increased in middle-aged men with primary or secondary osteoporosis and is correlated with bone remodeling markers, hip bone mineral density, and vertebral fracture risk.

Relationship between glomerular hyperfiltration and ACE insertion/deletion polymorphism in type 1 diabetic children and adolescents.

OBJECTIVE: Glomerular hyperfiltration may predict diabetic nephropathy in type 1 diabetes, and some studies suggest that the ACE D allele is associated with diabetic nephropathy. The aim of this study was to examine a possible relationship between glomerular hyperfiltration and ACE insertion/deletion (I/D) polymorphism in type 1 diabetic children and adolescents. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted to examine the relationship between glomerular hyperfiltration and ACE (I/D) polymorphism in 76 type 1 diabetic children and adolescents without diabetic nephropathy (mean +/- SD: age 16 +/- 3 years; diabetes duration 7 +/- 4 years; age at diabetes onset 9 +/- 4 years; HbA1c 9.5 +/- 1.9%). Glomerular hyperfiltration (defined as a glomerular filtration rate [GFR] > or = 135 ml.min-1. 1.73 m-2 and by 51Cr-labeled EDTA plasma disappearance technique) and ACE I/D genotypes and plasma levels (enzyme-linked immunosorbent assay [ELISA] method) were determined. RESULTS: Of the patients, 29 (38%) displayed glomerular hyperfiltration. An association between glomerular hyperfiltration and ACE (I/D) polymorphism was observed (chi 2 = 7.09, P = 0.029) because of a reduced proportion of DD genotypes among patients with glomerular hyperfiltration (4 vs. 19; chi 2 = 6.03, P = 0.014) and not because of an excess of the II genotype (5 vs. 9; chi 2 = 0.04, P = 0.83). Age, diabetes duration, age at diabetes onset, and HbA1c were not different according to genotype. Patients with glomerular hyperfiltration had low plasma ACE levels, compared with those with normal glomerular filtration (457 +/- 157 vs. 553 +/- 186 micrograms/l; P = 0.027). CONCLUSIONS: These results suggest an unexpected association between glomerular hyperfiltration and ACE (I/D) polymorphism, characterized by a defect of the DD genotype among type 1 diabetic children and adolescents with glomerular hyperfiltration.

Work and chronic health effects among fishermen in Chioggia, Italy.

OBJECTIVES: To evaluate whether there is an association between deep-sea fishing and common chronic disease. METHODS: The study was cross-sectional, simultaneously considering groups of fishermen and non-fishermen. Information on life-style and work was collected by means of questionnaires, and clinical data were collected by specialists in: Internal Medicine (general clinical examination), Cardiology (ECG, measurement of arterial pressure), Pneumology (measurement of spirometric volumes), ENT (clinical examination of the ear, nose and throat, including audiometry), Ophthalmology (examination of lens). Beside the common statistical methods, the logistic stepwise regression analysis was used in order to find the risk factors of the diseases, and to correct the risk estimates for the confounding variables. RESULTS: Fisherman had prolonged hours of continuous work, which were found to be correlated with high cigarette and alcohol consumption. Significant associations were found between, on the one hand, work accidents, noise-induced hearing loss, solar keratosis, cataracts, obstructive bronchitis, rhino-sinusitis, otitis media with tympanic perforation, ECG alterations, and, on the other hand, various aspects of fisherman occupation, mainly fishing in high sea and work duration as fisherman. CONCLUSION: Deep-sea fishing is a stressful and risky work; a reduction in the number of years at sea with reduced exposure to noise, poor weather conditions and sun, and a lower consumption of cigarettes and alcohol might result in fewer skin, eye respiratory and cardiovascular diseases, and injuries.

Development and validation of a prognostic index predicting death after upper gastrointestinal bleeding in patients with liver cirrhosis: a multicenter study.

Prognostic factors of the outcome of upper gastrointestinal bleeding in patients with cirrhosis are insufficiently defined. Pertinent clinical, biochemical, and endoscopic data of 332 upper gastrointestinal bleedings in 268 patients with cirrhosis observed in the participating centers during 31 months were recorded. Clinical data were analyzed until 40 days after bleeding. A further set of 82 bleedings was used as a validation group. Ninety-two of the 268 patients died within the time of the study, and 28 of the 82 patients of the validation group died. According to a stepwise logistic regression analysis, s-creatinine, ascites on admission, previous diagnosis of hepatocellular carcinoma, s-bilirubin, prothrombin index, varices as definite or probable source of bleeding, gender, and presentation with hemathemesis were the best set of covariates for predicting outcome. From them a prognostic index was developed and validated in the 82 further bleedings. Sensitivity and specificity in the cumulated training and test sets were 75 and 80%, respectively. In the present material, the prognostic index was significantly more efficient than Child-Pugh score or the prognostic index proposed by Garden et al. These data show that it is possible to predict the outcome of upper gastrointestinal bleeding in cirrhosis on the basis of few easily available data. The prognostic index we proposed and validated may become useful to predict the outcome of a bleeding and to select or stratify patients in clinical trials.