bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of L-Type Calcium Channels Induces Corticotropin-Releasing Factor Secretion from Human Placental Trophoblasts*
Authors: Robidoux Jacques , Simoneau Lucie , Masse André , Lafond Julie 
Published: January 2014

AbstractThe ultimate outcome of pregnancy, parturition, is a well orchestrated process in which placental corticotropin-releasing factor (CRF) seems to play an important role. The objective of the present study was to investigate the involvement of L-type calcium channels and calcium-dependent signaling in the depolarization-induced CRF release from human syncytiotrophoblast. The basal secretion of CRF by trophoblastic cells, isolated from human term placenta, was maximal after their functional differentiation, which was monitored by hCG measurements. On the fourth day of culture, the basal CRF secretion of the cells in serum-free medium was linear between 2 and 8 h. Incubation of the trophoblasts with KCl, a depolarizing stimulus, or with Bay K8644, an L-type calcium channel agonist, for 3 or 8 h led to an increase in CRF secretion, but was without effect on its synthesis. This stimulated CRF release was calcium dependent, as it could be prevented by loading cells with 1,2-bis(0-Aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (acetoxymethyl) ester. Furthermore, the KCl-induced CRF secretion involved L-type calcium channels activation, as 2 μmol/L nitrendipine, an L-type specific blocker, abolished the stimulation. In trophoblasts, where we have previously shown calcium-dependent protein kinase C (cPKCs) activity, incubation with Bay K8644 also stimulated calcium calmodulin kinase II (CaMKII) and extracellular regulated kinase activities. In the present study we observed that CaMKII and cPKCs were linked to the Bay K8644-induced secretion of CRF, as only the autocamtide-2 related inhibitory peptide, a CaMKII inhibitor, and Gö6976, an inhibitor of μ and cPKCs partially prevented (30–78%) the activation of CRF release by Bay K8644. The use of PD 098056, an inhibitor of the ERKs kinases, showed no effect on CRF release. Taken together, these results support a depolarization-induced and calcium-dependent exocytotic-like secretion of CRF from human placental trophoblasts. In addition, CaMKII and cPKCs seem to be potential modulators or mediators of these calcium effects on CRF secretion.
Occurrence of Gonadoblastoma in Females with Turner Syndrome and Y Chromosome Material: A Population Study*
Authors: Gravholt Claus Højbjerg , Fedder Jens , Naeraa Rune Weis , Müller Jørn 
Published: January 2014

Abstract
The presence of Y chromosome material in patients with Turner syndrome is a risk factor for the development of gonadoblastoma. However, no cases with gonadoblastoma or other ovarian malignancies have been found in epidemiological studies of cancer, morbidity, or mortality in Turner syndrome. We examined 114 females with Turner syndrome for the presence of Y chromosome material by PCR. Initially, five different primer sets were used. Y Chromosome-positive individuals were further examined with an additional four primer sets. We found 14 (12.2%; 95% confidence interval, 6.9–19.7%) patients who had Y chromosome material. The karyotype in 7 of these patients did not suggest the presence of Y chromosome material. Seven of the patients had been ovariectomized before entering the study due to verified Y chromosome material, whereas three patients were operated upon after the DNA analysis. The histopathological evaluations showed that 1 of the 10 ovariectomized patients actually had a gonadoblastoma. The rest of the patients did not have gonadoblastoma or carcinoma in situ on histopathological evaluation. Three patients (age, &gt;50 yr) positive for Y chromosome material chose not to have ovariectomy performed, and detailed ultrasonographies did not suggest the presence of gonadoblastoma. The frequency of Y chromosome material is high in Turner syndrome (12.2%), but the occurrence of gonadoblastoma among Y-positive patients seems to be low (7–10%), and the risk may have been overestimated in previous studies, perhaps due to problems with selection bias. This study emphasizes the need for prospective unbiased studies.
Muscle Sympathetic Nerve Activity in Patients with Acromegaly
Authors: Capaldo Brunella , Lembo Giuseppe , Rendina Virgilio , Guida Raffaele , Marzullo Paolo , Colao Annamaria , Lombardi Gaetano , Saccà Luigi 
Published: January 2014

Abstract
Muscle sympathetic nerve activity was measured in nine acromegalic patients (age, 35 ± 4 yr; body mass index, 28 ± 2 kg/m2) and eight healthy subjects (age, 32 ± 3 yr; body mass index, 25 ± 2 kg/m2) by combining the forearm arterial-venous difference technique with the tracer method[ infusion of tritiated norepinephrine (NE)]. Muscle NE release was quantified both at rest and during physiological hyperinsulinemia while maintaining euglycemia (∼90 mg/dL) by means of the euglycemic clamp.
Arterial plasma NE was similar in the two groups at rest (197 ± 28 and 200 ± 27 pg/mL−1) and slightly increased during insulin infusion. Forearm NE release was 2.33 ± 0.55 ng·liter−1·min−1 in healthy subjects and 2.67 ± 0.61 ng·liter−1·min−1 in acromegalic subjects in the basal state and increased to a similar extent during insulin infusion in both groups (3.13 ± 0.71 and 3.32 ± 0.75 ng·L−1· min−1, P &lt; 0.05 vs. basal), indicating a normal stimulatory effect of insulin on muscle sympathetic activity. In contrast, insulin-stimulated forearm glucose uptake was markedly lower in acromegalic patients (2.3 ± 0.4 mg·L−1·min−1) than in control subjects (7.9 ± 1.3 mg·L−1·min−1, P &lt; 0.001), indicating the presence of severe insulin resistance involving glucose metabolism.
Our data demonstrate that patients with long-term acromegaly have normal sympathetic activity in the skeletal muscle in the basal, postabsorptive state and normal increments in NE spillover in response to the sympatho-excitatory effect of insulin. Thus, the presence of severe insulin resistance in acromegaly is not accounted for by adrenergic mechanisms.
Effects of Human Recombinant Luteinizing Hormone and Follicle-Stimulating Hormone in Patients with Acquired Hypogonadotropic Hypogonadism: Study of Sertoli and Leydig Cell Secretions and Interactions
Authors: Young Jacques , Couzinet Beatrice , Chanson Philippe , Brailly Sylvie , Loumaye Ernest , Schaison Gilbert 
Published: January 2014

Abstract
Experimental data suggest that FSH-stimulated Sertoli cells can enhance LH-induced Leydig cell testosterone (T) production. The function of Leydig and Sertoli cells can be selectively studied by using recombinant human LH (rhLH) and recombinant human FSH (rhFSH) in patients with complete gonadotropin deficiency. The aim of the present study was to assess the secretion of testicular T, estradiol (E2), and inhibin B and the physiological relevance of the Sertoli-Leydig cell interaction in man. For that purpose, six patients with acquired complete hypogonadotropic hypogonadism received the following treatments for three periods of 1 month in a random order: 1) rhLH, 900 IU/day sc; 2) rhFSH, 150 IU/day sc; and 3) combined rhLH/rhFSH treatments. Each treatment period was separated by a washout period of 15 days. Plasma LH, FSH, T, E2, and inhibin B were measured before and every 10 days during each treatment. During rhLH administration, mean plasma LH levels rose significantly from 0.4 ± 0.2 IU/L to 11.7 ± 1.2 IU/L (P &lt; 0.01) and plasma FSH levels did not change. rhFSH administration induced a significant increase in plasma FSH levels (from 0.5 ± 0.4 to 12.1 ± 1.4 IU/L; P &lt; 0.01), whereas mean plasma LH levels remained low. Mean plasma E2 levels were unchanged during rhFSH treatment, but they increased significantly during rhLH from 22 ± 4 to 54 ± 8 pmol/L (P &lt; 0.01) and during rhLH plus rhFSH administration. rhFSH treatment induced a sustained elevation of mean plasma inhibin B levels from 58 ± 13 to 175 ± 25 pg/mL (P &lt; 0.01), similar to the increase occurring during rhFSH plus rhLH administration. In contrast, mean plasma inhibin B levels did not increase during rhLH administration. Finally, a similar and significant increase in mean plasma T levels occurred during both rhLH and rhLH plus rhFSH treatment from 0.9 ± 0.3 to 5.4 ± 0.7 nmol/L (P &lt; 0.01) and from 1.0 ± 0.4 to 6.0 ± 0.9 nmol/L (P &lt; 0.01), respectively. In contrast, during rhFSH treatment mean plasma T levels remained unchanged when compared with baseline. In conclusion: 1) the increase of plasma E2 induced by rhLH and the absence of effect of rhFSH confirm that Leydig cells are the major site of testicular E2 production in man; 2) the secretion of inhibin B is increased by rhFSH and not by rhLH, and, thus, Sertoli cells seem to be the main source of inhibin B production; and 3) the increase of plasma T induced by rhLH is not enhanced by rhFSH. These results suggest that the stimulatory effect of FSH on Leydig cell steroidogenesis by a Sertoli cell paracrine factor does not seem to play a major physiologic role in man.
Tumor Necrosis Factor Microsatellite Polymorphism Influences the Development of Insulin Dependency in Adult-Onset Diabetes Patients with the DRB1∗1502-DQB1∗0601 Allele and Anti-Glutamic Acid Decarboxylase Antibodies
Authors: Obayashi Hiroshi , Hasegawa Goji , Fukui Michiaki , Kamiuchi Kenji , Kitamura Akane , Ogata Masakazu , Kanaitsuka Toshihiro , Shigeta Hirofumi , Kitagawa Yoshihiro , Nakano Koji , Nishimura Masataka , Ohta Mitsuhiro , Nakamura Naoto 
Published: January 2014

Abstract
Recently, several studies have demonstrated that tumor necrosis factor microsatellite polymorphism (TNFa) contributes to the susceptibility of type 1 diabetes. This study investigates the influence of TNFa on the predisposition to insulin dependency in adult-onset diabetic patients with type 1 diabetes-protective human leukocyte antigen haplotypes. The TNFa of three groups of DRB1∗1502-DQB1∗0601-positive diabetic patients who had initially been nonketotic and noninsulin dependent for more than 1 yr was analyzed. Group A included 11 antibodies to glutamic acid decarboxylase (GADab)-positive patients who developed insulin dependency within 4 yr of diabetes onset. Group B included 11 GADab-positive patients who remained noninsulin dependent for more than 12 yr. Group C included 12 GADab-negative type 2 diabetes, and a control group included 18 nondiabetic subjects. In the group C and control subjects, DRB1∗1502-DQB1∗0601 was strongly associated with the TNFa13 allele. DRB1∗1502-DQB1∗0601 was strongly associated with the TNFa12 allele among the group A patients, but not among the group B patients. Interestingly, sera from all patients with non-TNFa12 and non-TNFa13 in group B reacted with GAD65 protein by Western blot. These results suggest that TNFa is associated with a predisposition to progression to insulin dependency in GADab/DRB1∗1502-DQB1∗0601-positive diabetic patients initially diagnosed with type 2 diabetes and that determination of these patients’ TNFa genotype may allow for better prediction of their clinical course.
Increased Risk for Nonmedullary Thyroid Cancer in the First Degree Relatives of Prevalent Cases of Nonmedullary Thyroid Cancer: A Hospital-Based Study
Authors: Pal Tuya , Vogl Florian D. , Chappuis Pierre O. , Tsang Richard , Brierley James , Renard Helene , Sanders Kevin , Kantemiroff Tania , Bagha Sabira , Goldgar David E. , Narod Steven A. , Foulkes William D. 
Published: January 2014

The genetic basis for nonmedullary forms of thyroid cancer (NMTC) is less well established than that of medullary thyroid cancer. However, epidemiological and family studies suggest that a proportion of NMTC may be due to inherited predisposition. To estimate the familial risk of thyroid cancer, we conducted a hospital-based case-control study at the Princess Margaret Hospital in Toronto, Ontario, Canada, and at 2 university hospitals in Montréal, Québec, Canada. We obtained pedigrees from 339 unselected patients diagnosed with NMTC and from 319 unaffected ethnically matched controls. Family histories of cancer were obtained from the cases and controls for 3292 first degree relatives of cases and controls. Seventeen cases (5.0%) and 2 controls (0.6%) reported at least one first degree relative with thyroid cancer.
In relatives of patients with thyroid cancer, the incidence of any type of cancer (including NMTC) was 38% higher than in relatives of controls (incidence rate ratio, 1.4; 95% confidence interval, 1.1–1.7). The relative risk for thyroid cancer was 10-fold higher in relatives of cancer patients than in controls (incidence rate ratio, 10.3; 95% confidence interval, 2.2–47.6).
Our findings suggest that hereditary or other familial factors are important in a small proportion of NMTC. Molecular studies are needed to determine the genetic basis of cancer susceptibility in these families.
Blood-Brain Barrier Transport and Brain Metabolism of Glucose during Acute Hyperglycemia in Humans1
Authors: Hasselbalch Steen G. , Knudsen Gitte M. , Capaldo Brunella , Postiglione Alfredo , Paulson Olaf B. 
Published: January 2014

It is controversial whether transport adaptation takes place in chronic or acute hyperglycemia. Blood-brain barrier glucose permeability and regional brain glucose metabolism (CMRglc) was studied in acute hyperglycemia in six normal human subjects (mean age, 23 yr) using the double indicator method and positron emission tomography and[ 18F]fluorodeoxyglucose as tracer. The Kety-Schmidt technique was used for measurement of cerebral blood flow (CBF). After 2 h of hyperglycemia (15.7 ± 0.7 mmol/L), the glucose permeability-surface area product from blood to brain remained unchanged (0.050 ± 0.008 vs. 0.059 ± 0.031 mL/100 g·min). The unidirectional clearance of[ 18F]fluorodeoxyglucose (K1*) was reduced from 0.108 ± 0.011 to 0.061 ± 0.005 mL/100 g·min (P &lt; 0.0004). During hyperglycemia, global CMRglc remained constant (21.4 ± 1.2 vs. 23.1 ± 2.2 μmol/100 g·min, normo- and hyperglycemia, respectively). Except for a significant increase in white matter CMRglc, no regional difference in CMRglc was found. Likewise, CBF remained unchanged.
The reduction in K1* was compatible with Michaelis-Menten kinetics for facilitated transport. Our findings indicate no major adaptational changes in the maximal transport velocity or affinity to the blood-brain barrier glucose transporter. Finally, hyperglycemia did not change global CBF or CMRglc.
The Relationship between Steroidogenic Factor 1 and DAX-1 Expression and in Vitro Gonadotropin Secretion in Human Pituitary Adenomas1
Authors: Aylwin S. J. B. , Welch J. P. , Davey C. L. , Geddes J. F. , Wood D. F. , Besser G. M. , Grossman A. B. , Monson J. P. , Burrin J. M. 
Published: January 2014

The orphan nuclear receptors, steroidogenic factor 1 (SF-1) and DAX-1, are involved in gonadotroph differentiation, and SF-1 has been shown to activate the LH-β and glycoprotein hormone α-subunit (αGSU) gene promoters. Pituitary adenomas from 34 patients [13 somatotroph tumors, 4 prolactinomas, and 17 clinically nonfunctioning pituitary adenomas (NFPAs)] were enzymatically dispersed and cultured in vitro for 48 h. Tissue culture medium was collected and assayed for LH, FSH, and αGSU; messenger RNA was extracted from adherent cells, and expression of SF-1 and DAX-1 messenger RNA was determined by RT-PCR and verified by direct DNA sequencing. The presence of DAX-1 protein in tumor tissue was confirmed by immunocytochemistry.DAX-1 was demonstrated in all NFPAs, 7 of 13 somatotroph tumors and 0 of 4 prolactinomas. SF-1 expression occurred in 8 of 16 NFPAs, 4 of 12 somatotroph tumors, and 1 of 4 prolactinomas. LH secretion in vitro was greater in NFPAs that were SF-1 positive (P &lt; 0.05). Neither FSH secretion nor αGSU secretion in vitro were significantly related to the expression of SF-1 or DAX-1. SF-1-positive somatotroph tumors immunostained positively for LH-β and/or FSH-β and secreted gonadotropins in vitro.SF-1 expression is associated with the in vitro secretion of LH by NFPAs. A proportion of somatotroph tumors also express SF-1 and DAX-1 and secrete gonadotropin hormones in vitro.
Specific Factors Predict the Response to Pulsatile Gonadotropin-Releasing Hormone Therapy in Polycystic Ovarian Syndrome1
Authors: Gill Sabrina , Taylor Ann E. , Martin Kathryn A. , Welt Corrine K. , Adams Judith M. , Hall Janet E. 
Published: January 2014

Ovulation induction is particularly challenging in patients with polycystic ovarian syndrome (PCOS) and may be complicated by multifollicular development. Pulsatile GnRH stimulates monofollicular development in women with anovulatory infertility; however, ovulation rates are considerably lower in the subgroup of patients with PCOS. The aim of this retrospective study was to determine specific hormonal, metabolic, and ovarian morphological characteristics that predict an ovulatory response to pulsatile GnRH therapy in patients with PCOS.
Subjects with PCOS were defined by chronic amenorrhea or oligomenorrhea and clinical and/or biochemical hyperandrogenism in the absence of an adrenal or pituitary disorder. At baseline, gonadotropin dynamics were assessed by 10-min blood sampling, insulin resistance by fasting insulin levels, ovarian morphology by transvaginal ultrasound, and androgen production by total testosterone levels. Intravenous pulsatile GnRH was then administered. During GnRH stimulation, daily blood samples were analyzed for gonadotropins, estradiol (E2), progesterone, inhibin B, and androgen levels, and serial ultrasounds were performed.
Forty-one women with PCOS underwent a total of 144 ovulation induction cycles with pulsatile GnRH. Fifty-six percent of patients ovulated with 40% of ovulatory patients achieving pregnancy. Among the baseline characteristics, ovulatory cycles were associated with lower body mass index (P &lt; 0.05), lower fasting insulin (P = 0.02), lower 17-hydroxyprogesterone and testosterone responses to hCG (P &lt; 0.03) and higher FSH (P &lt; 0.05). In the first week of pulsatile GnRH treatment, E2 and the size of the largest follicle were higher (P &lt; 0.03), whereas androstenedione was lower (P &lt; 0.01) in ovulatory compared with anovulatory patients. Estradiol levels of 230 pg/mL (844 pmol/L) or more and androstenedione levels of 2.5 ng/mL (8.7 nmol/L) or less on day 4 and follicle diameter of 11 mm or more by day 7 of pulsatile GnRH treatment had positive predictive values for ovulation of 86.4%, 88.4%, and 99.6%, respectively. Ovulatory patients who conceived had lower free testosterone levels at baseline (P &lt; 0.04).
In conclusion, pulsatile GnRH is an effective and safe method of ovulation induction in a subset of patients with PCOS. Patient characteristics associated with successful ovulation in response to pulsatile GnRH include lower body mass index and fasting insulin levels, lower androgen response to hCG, and higher baseline FSH. In ovulatory patients, high free testosterone is negatively associated with pregnancy. A trial of pulsatile GnRH therapy may be useful in all PCOS patients, as E2 and androstenedione levels on day 4 or follicle diameter on day 7 of therapy are highly predictive of the ovulatory response in this group of patients.
The Acute Leptin Response to GH
Authors: Lissett Catherine A. , Clayton Peter E. , Shalet Stephen M. 
Published: January 2014

The effect of an acute bolus of GH on serum leptin in normal individuals and the factors affecting this response have not previously been studied. Seventeen healthy volunteers with normal body mass index, with ages ranging from 20.5–78.2 yr were studied. Each subject received three single doses of GH in random order at least 4 wk apart. Bioimpedence analysis was performed to provide estimates of fat and lean masses. Serum samples for leptin, insulin, and IGF-I were taken 0, 18, 24, 48, 72, and 120 h after each dose of GH.
Leptin levels changed significantly after the 0.67- and 7-mg doses of GH, but not after the 0.27-mg dose. Compared with baseline, there was a significant elevation (P &lt; 0.001) in serum leptin levels at 24 h, followed by a significant decrease (P &lt; 0.01) at 72 h.
Baseline and peak leptin levels were significantly determined by gender, fat mass, and log10 insulin. Nadir leptin levels were significantly determined by gender and fat mass. In contrast, the increment in leptin levels was significantly determined by age, although this only accounted for 24% of the variability in the increment in leptin levels.
We have demonstrated that administration of a single bolus dose of GH significantly increases serum leptin levels, followed by a significant nadir. This occurs not only after a supraphysiological dose of GH, but also after 0.67 mg, a dose within the physiological replacement range. The increment in leptin increases with advancing age, suggesting that at the level of the adipocyte, aging increases responsiveness to GH. However, this only partially explains the changes seen, and it is likely that another factor(s) is involved in the acute impact of GH on circulating leptin levels. The presence of a significant nadir after the peak in leptin levels supports the existence of a negative feedback loop, linking circulating leptin to its own biosynthesis in adipose tissue, mediated by peripheral leptin receptors.
These data provide unequivocal evidence that GH can affect serum leptin levels in the absence of a change in body composition.
The Cardiovascular Risk of Adult GH Deficiency (GHD) Improved after GH Replacement and Worsened in Untreated GHD: A 12-Month Prospective Study
Authors: Colao Annamaria , di Somma Carolina , Pivonello Rosario , Cuocolo Alberto , Spinelli Letizia , Bonaduce Domenico , Salvatore Marco , Lombardi Gaetano 
Published: January 2014

Increased cardiovascular morbidity and mortality were reported in GH deficiency (GHD), and GH replacement can ameliorate cardiac abnormalities of adult GHD patients. To test the potential progression of untreated GHD on the cardiovascular risk and cardiac function, cardiovascular risk factors, cardiac size, and performance were prospectively evaluated in 15 GHD patients (age, 18–56 yr) who were treated with recombinant GH at the dose of 0.15–1.0 mg/d, 15 GHD patients (age, 18–56 yr) who refused GH replacement, and 30 healthy subjects (age, 18–53 yr).
Electrocardiogram, systolic and diastolic blood pressure, and heart rate measurement, serum IGF-I, total cholesterol, low- and high-density lipoprotein (LDL, HDL) cholesterol, triglycerides, and fibrinogen level assay, echocardiography, and equilibrium radionuclide angiography were performed basally and after 12 months.
At study entry, low IGF-I levels, unfavorable lipid profile, and inadequate cardiac and physical performance were found in GHD patients compared with controls. After 12 months of GH treatment, IGF-I levels normalized; HDL-cholesterol levels, left ventricular (LV) mass index (LVMi), left ventricular ejection fraction (LVEF) at peak exercise, peak filling rate, exercise duration and capacity significantly increased; total- and LDL-cholesterol levels significantly decreased. After 12 months in GH-untreated GHD patients, IGF-I levels remained stable, and HDL-cholesterol levels, LVEF both at rest and at peak exercise, and exercise capacity were further reduced; total- and LDL-cholesterol levels increased slightly. LVEF at rest and its response at peak exercise normalized in 60 and 53.3%, respectively, of GH-treated patients and in none of the GH-untreated patients.
In conclusion, 12 months of GH replacement normalized IGF-I and improved lipid profile and cardiac performance in adult GHD patients. A similar period of GH deprivation induced a further impairment of lipid profile and cardiac performance. This finding strongly supports the need of GH replacement in adult GHD patients.