bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ligands for Peroxisome Proliferator-Activated Receptor γ Inhibit Growth and Induce Apoptosis of Human Papillary Thyroid Carcinoma Cells
Authors: Ohta Kazuyasu , Endo Toyoshi , Haraguchi Kazutaka , Hershman Jerome M. , Onaya Toshimasa 
Published: January 2014

Ligands for peroxisome proliferator-activated receptor γ (PPARγ) induce apoptosis and exert antiproliferative effects on several carcinoma cell lines. The present study investigates the expression of PPARγ and the possibility that agonists for PPARγ also inhibit the growth of human thyroid carcinoma cells. We examined this hypothesis using six cell lines, designated BHP thyroid carcinoma cells, which originated from patients with papillary thyroid carcinoma. RT-PCR analysis revealed that the thyroid carcinoma cell lines BHP2–7, 7–13, 10–3, and 18–21 express PPARγ. More PPARγ was expressed in carcinoma than in adjacent normal thyroid tissue in three of six samples of human papillary carcinoma of the thyroid.
PPARγ-positive thyroid carcinoma cells were treated with agonists of PPARγ, troglitazone, BRL 49653, and 15-deoxy-Δ12,14-prostaglandin J2. Troglitazone (10μ mol/L), BRL 49653 (10 μmol/L), and 15-deoxy-Δ12,14-prostaglandin J2 (1 μg/mL) decreased[ 3H]thymidine incorporation and reduced cell number, respectively, in BHP carcinoma cell lines that expressed PPARγ. Under low serum conditions, ligands for PPARγ induced condensation of the nucleus and fragmentation of chromatin into nucleosome ladders. These findings indicate that the death of thyroid carcinoma cells is a form of apoptosis.
To investigate the molecular mechanism of the apoptosis, we assessed expression of the apoptosis-regulatory genes bcl-2, bax, and c-myc. Troglitazone significantly increased the expression of c-myc messenger RNA but had no effect on the expression of bcl-2 and bax in thyroid carcinoma cells. These results suggest that, at least in part, the induction of apoptosis in human papillary thyroid carcinoma cells may be due to an increase of c-myc.
Troglitazone (500 mg/kg·day) significantly inhibited tumor growth and prevented distant metastasis of BHP18–21 tumors in nude mice in vivo.
Taken together, these results suggest that PPARγ agonist inhibit cell growth of some types of human thyroid cancer.
Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency: Alterations in Cortisol Pharmacokinetics at Puberty
Authors: Charmandari Evangelia , Hindmarsh Peter C. , Johnston Atholl , Brook Charles G. D. 
Published: January 2014

In congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, treatment with glucocorticoid and mineralocorticoid substitution is not always satisfactory. Suboptimal control is often observed in pubertal patients, despite adequate replacement doses and adherence to treatment. We investigated whether the pubertal process is associated with alterations in cortisol pharmacokinetics resulting in a loss of control of the hypothalamic-pituitary-adrenal axis.
We determined the pharmacokinetics of hydrocortisone administered iv as a bolus. A dose of 15 mg/m2 body surface area was given to 14 prepubertal (median age, 9.4 yr; range, 6.1–10.8 yr), 20 pubertal (median, 13.5 yr; range, 10.6–16.8 yr), and 6 postpubertal (median, 18.2 yr; range, 17.2–20.3 yr) patients with salt-wasting CAH. All patients were on standard replacement therapy with hydrocortisone and 9α-fludrocortisone. Serum total cortisol concentrations were measured at 10-min intervals for 6 h following iv hydrocortisone bolus and analyzed using a solid-phase RIA.
The serum total cortisol clearance curve was monoexponential. Mean clearance was significantly higher in the pubertal group (mean, 427.0 mL/min; sd, 133.4) compared with the prepubertal (mean, 248.7 mL/min; sd, 100.6) and postpubertal (mean, 292.4 mL/min; sd, 106.3) (one-way ANOVA, F = 9.8, P &lt; 0.001) groups. This effect persisted after adjustment for body mass index. The mean volume of distribution was also significantly higher in the pubertal (mean, 49.5 L; sd, 12.2) than the prepubertal (mean, 27.1 L; sd, 8.4) patients but not in the postpubertal (mean, 40.8 L; sd, 16) (ANOVA, F = 15.2, P &lt; 0.001) patients. The significance remained after correction for body mass index. There was no significant difference in mean half-life of total cortisol in prepubertal (mean, 80.2 min; sd, 19.4), pubertal (mean, 84.4 min; sd, 24.9), and postpubertal (mean, 96.7 min; sd, 9.9) patients. Similar differences between groups were observed when the pharmacokinetic parameters of free cortisol were examined. In addition, the half-life of free cortisol was significantly shorter in females compared with males (P = 0.04).
These data suggest that puberty is associated with alterations in cortisol pharmacokinetics resulting in increased clearance and volume of distribution with no change in half-life. These alterations probably reflect changes in the endocrine milieu at puberty and may have implications for therapy of CAH and other conditions requiring cortisol substitution in the adolescent years.
Mutational Analysis and Genotype-Phenotype Correlation of the PHEX Gene in X-Linked Hypophosphatemic Rickets
Authors: Holm Ingrid A. , Nelson Anne E. , Robinson Bruce G. , Mason Rebecca S. , Marsh Deborah J. , Cowell Christopher T. , Carpenter Thomas O. 
Published: January 2014

PHEX is the gene defective in X-linked hypophosphatemic rickets. In this study, analysis of PHEX revealed mutations in 22 hypophosphatemic rickets patients, including 16 of 28 patients in whom all 22 PHEX exons were studied. In 13 patients, in whom no PHEX mutation had been previously detected in 17 exons, the remaining 5 PHEX exons were analyzed and mutations found in 6 patients. Twenty different mutations were identified, including 16 mutations predicted to truncate PHEX and 4 missense mutations.Phenotype analysis was performed on 31 hypophosphatemic rickets patients with PHEX mutations, including the 22 patients identified in this study, 9 patients previously identified, and affected family members. No correlation was found between the severity of disease and the type or location of the mutation. However, among patients with a family history of hypophosphatemic rickets, there was a trend toward more severe skeletal disease in patients with truncating mutations. Family members in more recent generations had a milder phenotype. Postpubertal males had a more severe dental phenotype. In conclusion, although identifying mutations in PHEX may have limited prognostic value, genetic testing may be useful for the early identification and treatment of affected individuals. Furthermore, this study suggests that other genes and environmental factors affect the severity of hypophosphatemic rickets.
Hexoneogenesis in the Human Breast during Lactation
Authors: Sunehag Agneta L. , Louie Kathryn , Bier Jessica L. , Tigas Stelios , Haymond Morey W. 
Published: January 2014

Lactose is the major osmotic agent in milk. Therefore, lactose synthesis indirectly regulates milk volume. The aim of this study was to determine the source of glucose and galactose in lactose. Six healthy lactating women were studied twice, during a 24-h fast and during ingestion of a mixed macronutrient drink (Sustacal) using [U-13C]glucose and [2-13C]glycerol. Six additional lactating women were studied on one single occasion during ingestion of glucose labeled with [1-13C]glucose.
Using the ratios of [13C6] enrichments of glucose in lactose and plasma glucose and that of galactose in lactose and plasma glucose, we determined that 98 ± 3% of glucose and 68 ± 7% of galactose in lactose were derived from plasma glucose in the fed state, and 72 ± 4 and 51 ± 3%, respectively, after a 24-h fast. Virtually identical results (97 ± 6 and 64 ± 4%, respectively) were obtained during the glucose feeding study. On the basis of the [13C1] enrichment of glucose and galactose in lactose (derived from [2-13C]glycerol), glycerol contributes to the production of galactose but not glucose within the breast.
Thus, plasma glucose is an important source of lactose, but significant amounts of glucose and galactose in lactose are generated within the breast, a process denoted hexoneogenesis. In this process, glycerol is a precursor for milk galactose but not glucose.
Selenium Supplementation in Patients with Autoimmune Thyroiditis Decreases Thyroid Peroxidase Antibodies Concentrations
Authors: Gärtner Roland , Gasnier Barbara C. H. , Dietrich Johannes W. , Krebs Bjarne , Angstwurm Matthias W. A. 
Published: January 2014

AbstractIn areas with severe selenium deficiency there is a higher incidence of thyroiditis due to a decreased activity of selenium-dependent glutathione peroxidase activity within thyroid cells. Selenium-dependent enzymes also have several modifying effects on the immune system. Therefore, even mild selenium deficiency may contribute to the development and maintenance of autoimmune thyroid diseases. We performed a blinded, placebo-controlled, prospective study in female patients (n = 70; mean age, 47.5 ± 0.7 yr) with autoimmune thyroiditis and thyroid peroxidase antibodies (TPOAb) and/or Tg antibodies (TgAb) above 350 IU/ml. The primary end point of the study was the change in TPOAb concentrations. Secondary end points were changes in TgAb, TSH, and free thyroid hormone levels as well as ultrasound pattern of the thyroid and quality of life estimation. Patients were randomized into 2 age- and antibody (TPOAb)-matched groups; 36 patients received 200 μg (2.53 μmol) sodium selenite/d, orally, for 3months, and 34 patients received placebo. All patients were substituted with l-T4 to maintain TSH within the normal range. TPOAb, TgAb, TSH, and free thyroid hormones were determined by commercial assays. The echogenicity of the thyroid was monitored with high resolution ultrasound. The mean TPOAb concentration decreased significantly to 63.6% (P = 0.013) in the selenium group vs. 88% (P = 0.95) in the placebo group. A subgroup analysis of those patients with TPOAb greater than 1200 IU/ml revealed a mean 40% reduction in the selenium-treated patients compared with a 10% increase in TPOAb in the placebo group. TgAb concentrations were lower in the placebo group at the beginning of the study and significantly further decreased (P = 0.018), but were unchanged in the selenium group. Nine patients in the selenium-treated group had completely normalized antibody concentrations, in contrast to two patients in the placebo group (by χ2 test, P = 0.01). Ultrasound of the thyroid showed normalized echogenicity in these patients. The mean TSH, free T4, and free T3 levels were unchanged in both groups.We conclude that selenium substitution may improve the inflammatory activity in patients with autoimmune thyroiditis, especially in those with high activity. Whether this effect is specific for autoimmune thyroiditis or may also be effective in other endocrine autoimmune diseases has yet to be investigated.
Hypersecretion of FSH in Infant Boys and Girls Born Small for Gestational Age
Authors: Ibáñez Lourdes , Valls Carme , Cols Maria , Ferrer Angela , Marcos Maria Victoria , de Zegher Francis 
Published: January 2014

Prenatal growth restraint, as reflected in a low birthweight for gestational age, is a risk factor for postpubertal FSH hypersecretion and for reduced gonadal size. The ontogeny of the low-birthweight effect on the FSH-inhibin B feedback loop is unknown. Infancy is an episode of choice to study the possibility of an early low-birthweight effect on the FSH-inhibin B loop because this phase is characterized by high activity within the gonadal axis.
We assessed serum concentrations of FSH and inhibin B in 46 infants [26 girls and 20 boys; mean age, 4 months; range, 3–6 months; 17 appropriate for gestational age (AGA), 29 small for gestational age (SGA); mean birthweight, 3.2 kg for AGA vs. 2.3 kg for SGA], together with circulating levels of LH, E2, and free androgen index.
In SGA girls and boys, serum FSH levels were 2- and 4-fold higher (P &lt; 0.001), respectively, than in AGA controls of the same gender (7.3 ± 0.9 vs. 3.8 ± 0.4 IU/ml and 2.9 ± 0.5 vs. 0.7 ± 0.2 IU/ml). Serum LH, inhibin B, and free androgen index/E2 concentrations were similar in AGA and SGA infants.
In conclusion, prenatal growth restraint was found to be followed by elevated serum FSH concentrations in infant girls and boys. SGA infants seem to need an augmented FSH drive to fulfill inhibin B requirements on the afferent side of the feedback loop. The late-endocrine correlates of early growth restraint are herewith extended to include the main axis of reproduction in both genders. It remains to be studied whether FSH hypersecretion in infancy is a marker of subsequent subfertility.
Hydrochlorothiazide Effectively Reduces Urinary Calcium Excretion in Two Japanese Patients with Gain-of-Function Mutations of the Calcium-Sensing Receptor Gene
Authors: Sato Kohei , Hasegawa Yukihiro , Nakae Jun , Nanao Kenji , Takahashi Ikuko , Tajima Toshihiro , Shinohara Nozomi , Fujieda Kenji 
Published: January 2014

Gain-of-function mutations of the calcium-sensing receptor (CaR) gene cause autosomal dominant and/or sporadic hypocalcemia with hypercalciuria. Because treatment of the hypocalcemia with vitamin D and/or calcium in patients with such mutations results in increased hypercalciuria, nephrocalcinosis, and renal impairment, its use should be limited to alleviating the symptoms of symptomatic patients. Because thiazide diuretics have been successfully used to treat patients with hypercalciuria and hypoparathyroidism, they are theoretically useful in reducing urine calcium excretion and maintaining serum calcium levels in patients with gain-of-function mutations of the CaR gene. In this study, we report on the clinical course, molecular analysis, and effects of hydrochlorothiazide therapy in two Japanese patients with gain-of-function mutations of the CaR gene. Within a few weeks after birth, they developed generalized tonic seizures due to hypocalcemia (serum calcium values: 1.1 mmol/liter and 1.3 mmol/liter, respectively). Despite treatment with the standard dose of 1,25-dihydroxyvitamin D3 in one patient and 1α-hydroxyvitamin D3 in the other, acceptable serum calcium levels near the lower limit of normal were not established, and their urinary calcium excretion inappropriately increased. Addition of hydrochlorothiazide (1 mg/kg) reduced their urinary calcium excretion and maintained their serum calcium concentrations near the lower limit of normal, allowing the 1,25-dihydroxyvitamin D3 and 1α-hydroxyvitamin D3 doses to be reduced, and it alleviated their symptoms. A heterozygous missense mutation was identified in both patients. In one patient, the mutation was A843E in the seventh transmembrane domain of the CaR, and in the other it was L125P in the N-terminal extracellular domain. In vitro transient transfection of their mutant CaR cDNAs into HEK293 cells shifted the concentration-response curve of Ca2+ to the left.
In conclusion, two sporadic cases of hypercalciuric hypocalcemia were due to de novo gain-of-function mutations of the CaR gene. Hydrochlorothiazide with vitamin D3 successfully reduced the patients’ urinary calcium excretion and controlled their serum calcium concentrations and symptoms. Thiazide diuretics are effective in patients with gain-of function mutations of the CaR gene.
Transcriptional Repression of the α-Subunit Gene by Androgen Receptor Occurs Independently of DNA Binding but Requires the DNA-Binding and Ligand-Binding Domains of the Receptor
Authors: Heckert Leslie L. , Wilson Elizabeth M. , Nilson John H. 
Published: January 2014

AbstractThe pituitary glycoprotein hormones LH and FSH regulate the reproductive cycle and are sensitive to feedback by gonadal steroids. The common α-subunit shared by these hormones is transcriptionally repressed by androgen receptor (AR) in the presence of its ligand dihydrotestosterone. This identifies at least one mechanism that contributes to AR-dependent suppression of gonadotropin synthesis. Repression of α-subunit transcription by AR requires only the sequences within the first 480 bp of the promoter. While this region contains a high-affinity binding site for AR, this element does not mediate the suppressive effects of androgens. Instead, two other elements within the promoter-regulatory region (α-basal element and cAMP-regulatory element), which are important for expression of theα -subunit gene in gonadotropes, mediate the effects of AR. This suggests that AR inhibits activity of the α-subunit promoter by interfering with the transcriptional properties of the proteins that bind to α-basal element and the cAMP-regulatory elements. Furthermore, transfection analysis of various mutant ARs identified both the DNA-binding and ligand-binding domains of the receptor as critical for repression. Comparisons with the MMTV promoter revealed distinct structural requirements that underlie the transactivation and transrepression properties of AR.
Human and Murine Osteocalcin Gene Expression: Conserved Tissue Restricted Expression and Divergent Responses to 1,25-Dihydroxyvitamin D3in Vivo
Authors: Sims Natalie A. , White Christopher P. , Sunn Kate L. , Thomas Gethin P. , Drummond Melanie L. , Morrison Nigel A. , Eisman John A. , Gardiner Edith M. 
Published: January 2014

AbstractHuman and murine osteocalcin genes demonstrate similar cell-specific expression patterns despite significant differences in gene locus organization and sequence variations in cis-acting regulatory elements. To investigate whether differences in these regulatory regions result in an altered response to 1,25-dihydroxyvitamin D3[ 1,25-(OH)2D3] in vivo, we compared the response of the endogenous mouse osteocalcin gene to a bacterial reporter gene directed by flanking regions of the human osteocalcin gene in transgenic mice. Transgene expression colocalized with endogenous osteocalcin expression in serial sections, being detected in osteoblasts, osteocytes and hypertrophic chondrocytes. In calvarial cell culture lysates from transgenic and nontransgenic mice, the endogenous mouse osteocalcin gene did not respond to 1,25-(OH)2D3 treatment. Despite this, transgene activity was significantly increased in the same cells. Similarly, Northern blots of total cellular RNA and in situ hybridization studies of transgenic animals demonstrated a maximal increase in transgene expression at 6 h after 1,25-(OH)2D3 injection (23.6 ± 3.6-fold) with a return to levels equivalent to uninjected animals by 24 h (1.2 ± 0.1-fold). This increase in transgene expression was also observed at 6 h after 1,25-(OH)2D3 treatment in animals on a low calcium diet (25.2 ± 7.7-fold) as well as in transgenic mice fed a vitamin D-deficient diet containing strontium chloride to block endogenous 1,25-(OH)2D3 production (7.5 ± 0.9-fold). In contrast to the increased transgene expression levels, neither endogenous mouse osteocalcin mRNA levels nor serum osteocalcin levels were significantly altered after 1,25-(OH)2D3 injection in transgenic or nontransgenic mice, regardless of dietary manipulations, supporting evidence for different mechanisms regulating the response of human and mouse osteocalcin genes to 1,25-(OH)2D3. Although the cis- and trans-acting mechanisms directing cell-specific gene expression appear to be conserved in the mouse and human osteocalcin genes, responsiveness to 1,25-(OH)2D3 is not. The mouse osteocalcin genes do not respond to 1,25-(OH)2D3 treatment, but the human osteocalcin-directed transgene is markedly up-regulated under the same conditions and in the same cells. The divergent responses of these homologous genes to 1,25-(OH)2D3 are therefore likely to be due to differences in mouse and human osteocalcin-regulatory sequences rather than to variation in the complement of trans-acting factors present in mouse osteoblastic cells. Increased understanding of these murine-human differences in osteocalcin regulation may shed light on the function of osteocalcin and its regulation by vitamin D in bone physiology.
Loss of an Estrogen Receptor Isoform (ERαΔ3) in Breast Cancer and the Consequences of Its Reexpression: Interference with Estrogen-Stimulated Properties of Malignant Transformation
Authors: Erenburg I. , Schachter B. , Lopez R. Mira y , Ossowski L. 
Published: January 2014

AbstractComparison of mRNA ratios of a non-DNA-binding estrogen receptor (ERα) isoform, missing exon 3 (ERαΔ3), to the full-length ERα, in normal breast epithelium to that in primary breast cancers and breast cancer cell lines revealed a 30-fold reduction of this ratio in cancer cells (P &lt; 0.0001). To test what functions may have been affected by the loss of ERαΔ3, stable clones of MCF-7 cells expressing ectopic ERαΔ3 protein, at the range of physiological ERα, were generated. In vector-transfected controls the ERαΔ3-mRNA and protein were less than 10% while in the ERαΔ3-expressing clones, ERαΔ3-mRNA and protein ranged from 36–76% of the total ERα. Estrogen (E2) stimulated the expression of pS2-mRNA in pMV7 vector control cells, but the stimulation was reduced by up to 93% in ERαΔ3-expressing clones. In addition, several properties associated with the transformed phenotype were also strongly affected when ERαΔ3 protein was reexpressed. Compared with vector-transfected control cells, the saturation density of the ERαΔ3-expressing clones was reduced by 50–68%, while their exponential growth rate was only slightly (14.5 ± 5%) lower. The in vivo invasiveness of the ERαΔ3-expressing cells was significantly reduced (P = 0.007) by up to 79%. E2 stimulated anchorage-independent growth of the pMV7 vector control cells, but reduced it to below baseline levels in ERαΔ3 clones. The reduction of the pS2 response to E2 in the ERαΔ3-expressing clones and the E2 block of anchorage-independent growth to below baseline were more pronounced than expected from the dominant negative function of ERαΔ3. These observations suggest that E2 may activate an additional ERαΔ3-dependent inhibitory pathway. The drastic reduction of ERαΔ3 to ERα ratio in breast cancer, and the fact that when present in breast cancer cells this isoform leads to a suppression, rather than enhancement, of the transformed phenotype by E2 suggests that the regulation of ERα-mRNA splicing may need to be altered for the breast carcinogenesis to proceed.
Activities in Pit-1 Determine Whether Receptor Interacting Protein 140 Activates or Inhibits Pit-1/Nuclear Receptor Transcriptional Synergy
Authors: Chuang F. Max , West Brian L. , Baxter John D. , Schaufele Fred 
Published: January 2014

Abstract
Pituitary-specific transcription of the evolutionarily related rat (r) GH and PRL genes involves synergistic interactions between Pit-1 and other promoter-binding factors including nuclear receptors. We show that Pit-1/thyroid hormone receptor (TR) and Pit-1/estrogen receptor (ER) synergistic activation of the rGH and rPRL promoters are globally similar. Both synergies depend upon the same activation functions in Pit-1 and also require activation function-2 conserved in TR and ER. The activation function-2 binding protein, RIP140, previously thought to be a nuclear receptor coactivator, strongly inhibits both Pit-1/TR and Pit-1/ER synergy. RIP140 inhibition is profoundly influenced, in a promoter-specific fashion, by a synergism-selective function in Pit-1: deletion of Pit-1 amino acids 72–100 switches RIP140 to an activator of Pit-1/ER and Pit-1/TR synergy at the rPRL promoter but not at the rGH promoter. Pit-1 amino acids 101–125 are required for RIP140 inhibition or activation again only at the rPRL promoter. Therefore, functions within one factor can determine the activity of a coactivator binding to its synergistic partner. This promoter context-specific synergistic interplay between transcription factors and coactivators is likely an essential determinant of cell-specific transcriptional regulation.