bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recombinant Human Insulin-Like Growth Factor I Treatment for 1 Week Improves Metabolic Control in Type 2 Diabetes by Ameliorating Hepatic and Muscle Insulin Resistance*
Authors: Cusi Kenneth , DeFronzo Ralph 
Published: January 2014

AbstractThe administration of recombinant human insulin-like growth factor I (rhIGF-I) reduces hyperglycemia and insulin requirements in subjects with severe insulin resistance syndromes and in patients with type 2 diabetes mellitus (T2DM). However, the mechanisms responsible for the improved metabolic control are incompletely understood. One proposed mechanism is that rhIGF-I therapy in T2DM may bypass early defects in insulin action (i.e. signal transduction), leading to improved hepatic and/or peripheral insulin sensitivity. To test this hypothesis, we used the euglycemic insulin clamp to measure the response to 7 days of rhIGF-I therapy (80 μg/kg, sc, twice daily) in eight poorly controlled T2DM subjects. rhIGF-I significantly improved fasting (203 ± 12 vs. 134 ± 14 mg/dL; P &lt; 0.01) and day-long (0800–1700 h; 234 ± 11 vs. 153 ± 10 mg/dL; P &lt; 0.01) plasma glucose levels. Basal endogenous glucose production decreased from 3.2 ± 0.2 to 2.7 ± 0.2 mg/kg lean body mass· min (P &lt; 0.03) despite a concomitant decline in the fasting plasma insulin concentration from 13 ± 5 to 5 ± 1 μU/mL (P &lt; 0.01). The decrement in basal endogenous glucose production was closely correlated with the decrement in fasting plasma glucose concentration (r = 0.78; P &lt; 0.01). Whole body insulin-stimulated glucose disposal increased by 27% (from 5.6 ± 0.8 to 7.1 ± 0.8 mg/kg lean body mass·min; P &lt; 0.01), but remained well below that observed in age- and weight-matched healthy subjects. The effects of rhIGF-I on endogenous glucose production and peripheral insulin sensitivity resemble those observed with intensified insulin regimens in T2DM. We conclude that 7 days of sc rhIGF-I improves glucose control by improving hepatic and muscle insulin sensitivity, but it remains markedly abnormal. This indicates that an intrinsic defect(s) responsible for insulin resistance in T2DM cannot be overcome by rhIGF-I treatment.
Carbohydrate-Induced Hypertriglyceridemia: An Insight into the Link between Plasma Insulin and Triglyceride Concentrations*
Authors: McLaughlin T. , Abbasi F. , Lamendola C. , Yeni-Komshian H. , Reaven G. 
Published: January 2014

Abstract
This study was initiated to test the hypothesis that endogenous hypertriglyceridemia results from a defect in the ability of insulin to inhibit the release of very low-density lipoprotein-triglyceride (TG) from the liver. To accomplish this goal, plasma glucose, insulin, free fatty acid (FFA), and TG concentrations were compared in 12 healthy volunteers, in response to diets containing either 40% or 60% of total calories as carbohydrate (CHO). The protein content of the two diets was similar (15% of calories), and the fat content varied inversely with the amount of CHO (45% or 25%). The diets were consumed in random order, and measurements were made of plasma glucose, insulin, FFA, and TG concentrations at the end of each dietary period, fasting, and at hourly intervals following breakfast and lunch. The results indicated that the 60% CHO diet resulted in higher fasting plasma TG concentrations associated with higher day-long plasma insulin and TG concentrations, and lower FFA concentrations. These results do not support the view that hypertriglyceridemia is secondary to a failure of insulin to inhibit hepatic TG secretion.
Immunotherapy for Medullary Thyroid Carcinoma by Dendritic Cell Vaccination
Authors: Schott Matthias , Seissler Jochen , Lettmann Melanie , Fouxon Vladimir , Scherbaum Werner A. , Feldkamp Joachim 
Published: January 2014

Recent studies suggest that immunization with autologeous dendritic cells (DCs) pulsed with tumor antigen result in protective immunity and rejection of established tumors in various human malignancies. The objective of this study was to develop a DC vaccination therapy in patients with metastasized medullary thyroid carcinoma (MTC). Mature DCs were generated from peripheral blood monocytes in the presence of granulocyte macrophage colony-stimulating factor, IL-4, and TNFα. After loading with calcitonin and carcinoembryonic antigen (CEA) peptide, 2–5 × 106 DCs were repeatedly delivered by sc injections.
During follow-up (mean, 13.1 months) all patients developed a strong delayed-type hypersensitivity skin reaction caused by perivascular and epidermal infiltration with CD4+ memory T cells and CD8+ cytotoxic T cells. Clinical responses with a decrease of serum calcitonin and CEA were initially documented in three of seven patients. One of these patients had a complete regression of detectable liver metastases and a significant reduction of pulmonary lesions. T-cell response in this patient revealed a calcitonin- and CEA-specific immunreactivity.
Our data indicate that vaccination with calcitonin and/or CEA peptide-pulsed DC results in the induction of a cellular, antigen-specific immune response in patients with MTC, leading to clinical response in some patients. Our approach may represent the basis for the development of new therapeutic strategies not only in MTC but also in other endocrine malignancies.
Heritability of Insulin Secretion and Insulin Action in Women with Polycystic Ovary Syndrome and Their First Degree Relatives1
Authors: Colilla Susan , Cox Nancy J. , Ehrmann David A. 
Published: January 2014

Polycystic ovary syndrome (PCOS), one of the most common endocrine disorders of reproductive age women, is associated with an increased risk of type 2 diabetes mellitus. Defects in both insulin action and insulin secretion contribute to this predisposition to diabetes, but the extent to which these defects are heritable among PCOS families has not been examined.
In the present study we used the frequently sampled iv glucose tolerance test to quantitate insulin secretion (AIRg), insulin action (Si), and their product (AIRg × Si) among women with PCOS (n= 33) and their nondiabetic first degree relatives (n = 48). We then quantitated the heritability of these measures from familial correlations estimated within a genetic model.
Familial (spousal, ρMF; parent-offspring, ρPO; and sibling, ρSS) correlations were derived for log-transformed body mass index (BMI) as well as for AIRg, Si, and AIRg × Si, the latter three of which were adjusted for BMI. There was no evidence of significant heritability for either lnBMI or lnSi in these families. In contrast, the sibling correlation (ρSS = 0.74) for lnAIRg was highly significant (χ2 = 7.65; 1 df; P= 0.006). In addition, the parameter quantitating insulin secretion in relation to insulin sensitivity [i.e. ln(AIRg × Si)] was significant among siblings (ρSS = 0.74;χ 2 = 4.32; 1 df; P = 0.04).
In summary, the results of the present study indicate that there is an heritable component to β-cell dysfunction in families of women with PCOS. We conclude that heritability of β-cell dysfunction is likely to be a significant factor in the predisposition to diabetes in PCOS.
The Contribution of Intraabdominal Fat to Gender Differences in Hepatic Lipase Activity and Low/High Density Lipoprotein Heterogeneity1
Authors: Carr Molly C. , Hokanson John E. , Zambon Alberto , Deeb Samir S. , Barrett P. Hugh R. , Purnell Jonathan Q. , Brunzell John D. 
Published: January 2014

Hepatic lipase (HL) hydrolyzes triglyceride and phospholipid in low and high density lipoprotein cholesterol (LDL-C and HDL-C, respectively), and elevated HL activity is associated with small, dense atherogenic LDL particles and reduced HDL2-C. Elevated HL activity is associated with increasing age, male gender, high amounts of intraabdominal fat (IAF), and the HL gene (LIPC) promoter polymorphism (C nucleotide at −514). We investigated the mechanisms underlying the difference in HL activity between men (n = 44) and premenopausal women (n = 63).Men had significantly more IAF (144.5 ± 80.9 vs. 66.5 ± 43.2 cm2, respectively; P&lt; 0.001), higher HL activity (220.9 ± 94.7 vs.129.9 ± 53.5 nmol/mL·min; P &lt; 0.001), more dense LDL (Rf, 0.277 ± 0.032 vs. 0.300 ± 0.024; P = 0.01), and less HDL2-C (0.19 ± 0.10 vs. 0.32± 0.16 mmol/L; P &lt; 0.001) than women. After adjusting for IAF and the LIPC polymorphism, men continued to have higher (but attenuated) HL activity (194.5 ± 80.4 vs.151.0 ± 45.2, respectively; P = 0.007) and lower HDL2-C (0.23 ± 0.11 vs. 0.29 ± 0.14 mmol/L; P = 0.02) than women. Using multiple regression, HL activity remained independently related to IAF (P &lt; 0.001), gender (P &lt; 0.001), and the LIPC genotype (P &lt; 0.001), with these factors accounting for 50% of the variance in HL activity.These data suggest that IAF is a major component of the gender difference in HL activity, but other gender-related differences, perhaps sex steroid hormones, also contribute to the higher HL activity seen in men compared with premenopausal women. The higher HL activity in men affects both LDL and HDL heterogeneity and may contribute to the gender difference in cardiovascular risk.
Germline RET 634 Mutation Positive MEN 2A-related C-Cell Hyperplasias Have Genetic Features Consistent with Intraepithelial Neoplasia
Authors: Diaz-Cano Salvador J. , de Miguel Manuel , Blanes Alfredo , Tashjian Robert , Wolfe Hubert J. 
Published: January 2014

C-cell hyperplasias are normally multifocal in multiple endocrine neoplasia type 2A. We compared clonality, microsatellite pattern of tumor suppressor genes, and cellular kinetics of C-cell hyperplasia foci in each thyroid lobe.
We selected 11 females from multiple endocrine neoplasia type 2A kindred treated with thyroidectomy due to hypercalcitoninemia. C-cell hyperplasia foci were microdissected for DNA extraction to analyze the methylation pattern of androgen receptor alleles and microsatellite regions (TP53, RB1, WT1, and NF1). Consecutive sections were selected for MIB-1, pRB1, p53, Mdm-2, and p21WAF1 immunostaining, DNA content analysis, and in situ end labeling. Appropriate tissue controls were run.
Only two patients had medullary thyroid carcinoma foci. Nine informative C-cell hyperplasia patients showed germline point mutation in RET, eight of them with the same androgen receptor allele preferentially methylated in both lobes. C-cell hyperplasia foci showed heterogeneous DNA deletions revealed by loss of heterozygosity of TP53 (12 of 20), RB1 (6 of 14), and WT1 (4 of 20) and hypodiploid G0/G1 cells (14 of 20), low cellular turnover (MIB-1 index 4.5%, in situ end labeling index 0.03%), and significantly high nuclear area to DNA index ratio.
MEN 2A (germline point mutation in RET codon 634) C-cell hyperplasias are monoclonal and genetically heterogeneous and show down-regulated apoptosis, findings consistent with an intraepithelial neoplasia. Concordant X-chromosome inactivation and interstitial gene deletions suggest clone expansions of precursors occurring at a point in embryonic development before divergence of each thyroid lobe and may represent a paradigm for other germline mutations.
TR Expression and Function in Human Bone Marrow Stromal and Osteoblast-Like Cells
Authors: Siddiqi Ayesha , Parsons Marie P. , Lewis John L. , Monson John P. , Williams Graham R. , Burrin Jacky M. 
Published: January 2014

Thyroid hormones influence both bone formation and bone resorption. In vitro studies demonstrate direct effects of thyroid hormones on cells of the osteoblast lineage. Transcriptional regulation by thyroid hormones is mediated by ligand-dependent transcription factors called TRs. The three main T3-binding TR isoforms are TRα1, TRβ1, and TRβ2. TRs have been identified in cells of the osteoblast lineage, but it is still not known whether TR isoform expression differs in primary cultures of human osteoblasts.We used immunocytochemistry, Western blotting, nuclear binding assays, and transient transfection studies to examine the expression of functional TR isoforms in primary cultures of osteoblasts (hOb) derived from explants of trabecular bone, in human bone marrow stromal cells (hBMS), which are believed to be the source of osteoblast progenitor cells, and for comparison in the transformed human osteosarcoma cell lines MG63 and SaOs-2. TRα1, TRβ1, and TRβ2 proteins were expressed in all cells, although expression was greatest in MG63 &gt; hBMS &gt; SaOs-2 &gt; hOb. Differences between isoforms were also apparent, with TRα1&gt; TRβ1 &gt; TRβ2 in all cell types. Incubation with [125I]T3 confirmed reversible T3 binding to cell nuclei. Specific binding was greatest in MG63 &gt; hBMS &gt; SaOs-2 &gt; hOb. Finally, endogenous TR activity was determined in transfections using a thyroid hormone response element derived from the rat GH gene linked to the luciferase reporter gene. In MG63 and hBMS cells T3 treatment increased luciferase activity 5.5 ± 0.7-fold (P &lt; 0.05), confirming the presence of endogenous receptors. In SaOs-2 and hOb cells, T3 treatment had no effect on thyroid hormone response element-thymidine kinase-luciferase expression, suggesting that in these cells TR expression was too low to be detected.These results indicate that three main TR isoforms are expressed in cells of the human osteoblast lineage, but that expression and endogenous TR activity are predominantly present in hBMS cells. Whether there are distinct mechanisms of thyroid hormone action mediated by TRα1, TRβ1, and TRβ2 in hOb and hBMS cells remains to be shown.
Acute Changes of Bone Turnover and PTH Induced by Insulin and Glucose: Euglycemic and Hypoglycemic Hyperinsulinemic Clamp Studies
Authors: Clowes Jackie A. , Robinson Robert T. , Heller Simon R. , Eastell Richard , Blumsohn Aubrey 
Published: January 2014

Bone turnover is acutely suppressed after feeding or oral glucose. Insulin infusion suppresses bone turnover and might mediate this effect, but this is confounded by a possible direct effect of hypoglycemia. We examined the effect of euglycemic hyperinsulinemia and hypoglycemic hyperinsulinemia on bone turnover using an insulin clamp. Sixteen men participated in this double-blind crossover study. Clamp induction involved infusion of insulin (80 mU/m2·min) while maintaining euglycemia (5 mmol/liter) for 40 min with a variable rate dextrose infusion. Glucose was lowered to 2.5 mmol/liter (hypoglycemic clamp) or maintained at 5 mmol/liter (euglycemic clamp) for a further 105 min. Nine controls received a matched saline infusion. Measurements included serum C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide, osteocalcin, and PTH.
Induction of hyperinsulinemia resulted in a reduction in PTH (27% ± 5; P &lt; 0.01), but no significant change in bone turnover from baseline. Hypoglycemic clamp resulted in suppression of serum C-terminal telopeptide of type I collagen by 34% ± 3, procollagen type I N-terminal propeptide by 15% ± 1, osteocalcin by 5% ± 1, and PTH by a further 12% ± 5 (all P &lt; 0.05). By contrast, there was no significant change in any marker of bone turnover during euglycemic clamp.
Postprandial hyperinsulinemia is unlikely to explain the acute suppression of bone turnover with feeding. The reduction in bone turnover during hypoglycemia may be related to hypoglycemia itself, acute changes in PTH, or other hormones released in response to hypoglycemia.
Comparative Genomic Hybridization Analysis of Adrenocortical Tumors
Authors: Sidhu Stan , Marsh Deborah J. , Theodosopoulos George , Philips Jeanette , Bambach Christopher P. , Campbell Peter , Magarey Christopher J. , Russell Colin F. J. , Schulte Klaus-Martin , Röher Hans-Dietrich , Delbridge Leigh , Robinson Bruce G. 
Published: January 2014

Comparative genomic hybridization (CGH) is a molecular cytogenetic technique that allows the entire genome of a tumor to be surveyed for gains and losses of DNA copy sequences. A limited number of studies reporting the use of this technique in adult adrenocortical tumors have yielded conflicting results.
In this study we performed CGH analysis on 13 malignant, 18 benign, and 1 tumor of indeterminate malignant potential with the aim of identifying genetic loci consistently implicated in the development and progression of adrenocortical tumors. Tissue samples from 32 patients with histologically proven adrenocortical tumors were available for CGH analysis. CGH changes were seen in all cancers, 11 of 18 (61%) adenomas, and the 1 tumor of indeterminate malignant potential. Of the adrenal cancers, the most common gains were seen on chromosomes 5 (46%), 12 (38%), 19 (31%), and 4 (31%). Losses were most frequently seen at 1p (62%), 17p (54%), 22 (38%), 2q (31%), and 11q (31%). Of the benign adenomas, the most common change was gain of 4q (22%).
Mann-Whitney analysis showed a highly significant difference between the cancer group (mean changes, 7.6) and the adenoma group (mean changes, 1.1) for the number of observed CGH changes (P &lt; 0.01). Logistic regression analysis showed that the number of CGH changes was highly predictive of tumor type (P &lt; 0.01).
This study has identified several chromosomal loci implicated in adrenocortical tumorigenesis. Activation of a protooncogene(s) on chromosome 4 may be an early event, with progression from adenoma to carcinoma involving activation of oncogenes on chromosomes 5 and 12 and inactivation of tumor suppressor genes on chromosome arms 1p and 17p.
Follicle Stimulating Hormone-Regulated Expression of Serum/Glucocorticoid-Inducible Kinase in Rat Ovarian Granulosa Cells: A Functional Role for the Sp1 Family in Promoter Activity
Authors: Alliston Tamara N. , Maiyar Anita C. , Buse Patricia , Firestone Gary L. , Richards JoAnne S. 
Published: January 2014

AbstractRecently, a family of novel, serine/threonine protein kinases has been identified. One of these transcriptionally inducible, immediate-early genes encodes serum/glucocorticoid inducible-protein kinase, sgk. By in situ hybridization, we show that sgk expression in the rat ovary is selectively localized to granulosa cells. In culture, FSH or forskolin, activators of the protein kinase A (PKA) pathway, rapidly (2 h) and transiently increased sgk mRNA levels in undifferentiated granulosa cells. Sgk mRNA exhibited a biphasic expression pattern, with maximal levels observed at 48 h of FSH/forskolin as granulosa cells differentiate to the preovulatory phenotype. Deletion analyses using sgk promoter-reporter constructs (−4.0 kb to −35 bp) identified a region between −63 and− 43 bp that mediated FSH and forskolin-responsive transcription in undifferentiated and differentiated granulosa cells. This G/C-rich region 1) conferred both basal and inducible transcription to the minimal −35 sgk promoter chloramphenicol acetyltransferase reporter construct, 2) specifically bound Sp1 and Sp3 present in granulosa cell extracts, and 3) bound recombinant Sp1. Mutation of 2 bp in this region not only prevented Sp1 and Sp3 binding, but also abolished the PKA-mediated transactivation observed when using the wild type construct. Sp1 and Sp3 DNA-binding activity and protein levels did not change significantly during sgk induction. Collectively, these data indicate that Sp1/Sp3 transactivation of the sgk promoter likely involves regulated, phosphorylation-dependent interaction with other factors. Thus the novel, biphasic induction of sgk that correlates with granulosa cell progression from proliferation to differentiation appears to involve sequential, coordinated actions of FSH, PKA, and transcription factors, including Sp1 and Sp3.
A Functional Sp1 Binding Site Is Essential for the Activity of the Adult Liver-Specific Human Insulin-Like Growth Factor II Promoter
Authors: Rodenburg Richard J. T. , Holthuizen P. Elly , Sussenbach John S. 
Published: January 2014

AbstractThe human gene encoding insulin-like growth factor II contains four promoters (P1–P4) that are differentially activated in various tissues during development. Expression of insulin-like growth factor II in adult liver tissue is directed by P1, which is activated by liver-enriched members of the CCAAT/enhancer binding protein family of transcription factors. In the present report we show that the region around −48 relative to the transcription start site contains a high affinity Sp1 binding site. This was demonstrated by electrophoretic mobility shift assays using nuclear extracts from Hep3B hepatoma cells and with specific antibodies directed against Sp1. Competition electrophoretic mobility shift assays revealed that the Sp1 binding site of P1 and a consensus Sp1 binding site bind Sp1 with comparable efficiencies. Mutation of the Sp1 binding site results in an 85% decrease in P1 promoter activity in transient transfection assays using two different cell lines, COS-7 and Hep3B. Investigation of P1 mutants in which the spacing of the Sp1 binding site and the transcription start site was increased showed that the role of the Sp1 binding site in regulation of P1 is position dependent. Interestingly, the Sp1-responsive element cannot be exchanged by a functional TATA box. Activation of P1 by transactivators CCAAT/enhancer binding protein-β and hepatocyte nuclear factor-3β is strongly impaired after mutation of the Sp1 binding site. These results demonstrate that the specific presence of a binding site for the ubiquitously expressed transcription factor Sp1 is of eminent importance for efficient activation of P1 by liver-enriched transactivators.
Coupling Specificity between Somatostatin Receptor sst2A and G Proteins: Isolation of the Receptor-G Protein Complex with a Receptor Antibody
Authors: Gu Yi-Zhong , Schonbrunn Agnes 
Published: January 2014

AbstractSomatostatin initiates its actions via a family of seven-transmembrane domain receptors. Of the five somatostatin receptor genes cloned, sst2 exists as two splice variants with the sst2A isoform being predominantly expressed. This receptor is widely distributed in endocrine, exocrine, and neuronal cells, as well as in hormonally responsive tumors, and leads to inhibition of secretion, electrical excitability, and cell proliferation. To investigate the specificity of signal transduction by the sst2A receptor, we developed antibodies against two overlapping peptides located within the C terminus of the receptor protein: peptide 2CSG, containing amino acids 334–348, and peptide 2CER, containing amino acids 339–359. Although antibodies to both peptides bound the inducing antigen with high affinity, only the antibodies against peptide 2CER precipitated the receptor. The best antibody, R2–88, precipitated about 80% of the sst2A receptor-ligand complex solubilized from transfected CHO cells and was specific for the sst2A receptor isotype. Addition of GTPγS (10μ m) to the immunoprecipitated ligand-sst2A receptor complex markedly accelerated ligand dissociation, indicating that G proteins remained functionally associated with the receptor in the immuno-precipitate. Analysis of the G proteins coprecipitated with the sst2A receptor by immunoblotting with G protein antibodies showed that both Gα and Gβ subunits were bound to the hormone-receptor complex. Immunoprecipitation of the receptor was not affected by the presence of bound ligand. However, G protein subunits were coprecipitated only with the hormone-occupied receptor. Thus, the unoccupied receptor has low affinity for G proteins, and hormone binding stabilizes the receptor-G protein complex. Use of subtype-specific G protein antisera further showed that Gαi1, Gαi2, and Gαi3 were complexed with the sst2A receptor whereas Gαo, Gαz, and Gαq were not. Together, these studies demonstrate that the sst2A receptor interacts selectively with Gαi proteins in a hormone-dependent manner. The finding that this receptor couples to all three Gαi subunits may help explain how somatostatin can regulate multiple signaling pathways.