bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing health worker capacity through distance learning: a comprehensive review of programmes in Tanzania
Authors: Nartker Anya J , Stevens Liz , Shumays Alyson , Kalowela Martin , Kisimbo Daniel , Potter Katy
Published: January 2011

Background

Tanzania, like many developing countries, faces a crisis in human resources for health. The government has looked for ways to increase the number and skills of health workers, including using distance learning in their training. In 2008, the authors reviewed and assessed the country's current distance learning programmes for health care workers, as well as those in countries with similar human resource challenges, to determine the feasibility of distance learning to meet the need of an increased and more skilled health workforce.

Methods

Data were collected from 25 distance learning programmes at health training institutions, universities, and non-governmental organizations throughout the country from May to August 2008. Methods included internet research; desk review; telephone, email and mail-in surveys; on-site observations; interviews with programme managers, instructors, students, information technology specialists, preceptors, health care workers and Ministry of Health and Social Welfare representatives; and a focus group with national HIV/AIDS care and treatment organizations.

Results

Challenges include lack of guidelines for administrators, instructors and preceptors of distance learning programmes regarding roles and responsibilities; absence of competencies for clinical components of curricula; and technological constraints such as lack of access to computers and to the internet. Insufficient funding resulted in personnel shortages, lack of appropriate training for personnel, and lack of materials for students.

Nonetheless, current and prospective students expressed overwhelming enthusiasm for scale-up of distance learning because of the unique financial and social benefits offered by these programs. Participants were retained as employees in their health care facilities, and remained in their communities and supported their families while advancing their careers. Space in health training institutions was freed up for new students entering in-residence pre-service training.

Conclusions

A blended print-based distance learning model is most feasible at the national level due to current resource and infrastructure constraints. With an increase in staffing; improvement of infrastructure, coordination and curricula; and decentralization to the zonal or district level, distance learning can be an effective method to increase both the skills and the numbers of qualified health care workers capable of meeting the health care needs of the Tanzanian population.
Differential endothelial cell gene expression by African Americans versusCaucasian Americans: a possible contribution to health disparity in vascular disease and cancer
Authors: Wei P , Milbauer LC , Enenstein J , Nguyen J , Pan W , Hebbel RP
Published: January 2011

Background

Health disparities and the high prevalence of cardiovascular disease continue to be perplexing worldwide health challenges. This study addresses the possibility that genetic differences affecting the biology of the vascular endothelium could be a factor contributing to the increased burden of cardiovascular disease and cancer among African Americans (AA) compared to Caucasian Americans (CA).

Methods

From self-identified, healthy, 20 to 29-year-old AA (n = 21) and CA (n = 17), we established cultures of blood outgrowth endothelial cells (BOEC) and applied microarray profiling. BOEC have never been exposed toin vivoinfluences, and their gene expression reflects culture conditions (meticulously controlled) and donor genetics. Significance Analysis of Microarray identified differential expression of single genes. Gene Set Enrichment Analysis examined expression of pre-determined gene sets that survey nine biological systems relevant to endothelial biology.

Results

At the highly stringent threshold of False Discovery Rate (FDR) = 0, 31 single genes were differentially expressed in AA.PSPHexhibited the greatest fold-change (AA > CA), but this was entirely accounted for by a homolog (PSPHL) hidden within thePSPHprobe set. Among other significantly different genes were: for AA > CA,SOS1, AMFR, FGFR3; and for AA < CA, ARVCF, BIN3, EIF4B.Many more (221 transcripts for 204 genes) were differentially expressed at the less stringent threshold of FDR <.05. Using the biological systems approach, we identified shear response biology as being significantly different for AA versus CA, showing an apparent tonic increase of expression (AA > CA) for 46/157 genes within that system.

Conclusions

Many of the genes implicated here have substantial roles in endothelial biology. Shear stress response, a critical regulator of endothelial function and vascular homeostasis, may be different between AA and CA. These results potentially have direct implications for the role of endothelial cells in vascular disease (hypertension, stroke) and cancer (via angiogenesis). Also, they are consistent with our over-arching hypothesis that genetic influences stemming from ancestral continent-of-origin could impact upon endothelial cell biology and thereby contribute to disparity of vascular-related disease burden among AA. The method used here could be productively employed to bridge the gap between information from structural genomics (for example, disease association) and cell function and pathophysiology.
Influenza A virus NS1 gene mutations F103L and M106I increase replication and virulence
Authors: Dankar Samar K , Wang Shuai , Ping Jihui , Forbes Nicole E , Keleta Liya , Li Yishan , Brown Earl G
Published: January 2011

Background

To understand the evolutionary steps required for a virus to become virulent in a new host, a human influenza A virus (IAV), A/Hong Kong/1/68(H3N2) (HK-wt), was adapted to increased virulence in the mouse. Among eleven mutations selected in the NS1 gene, two mutations F103L and M106I had been previously detected in the highly virulent human H5N1 isolate, A/HK/156/97, suggesting a role for these mutations in virulence in mice and humans.

Results

To determine the selective advantage of these mutations, reverse genetics was used to rescue viruses containing each of the NS1 mouse adapted mutations into viruses possessing the HK-wt NS1 gene on the A/PR/8/34 genetic backbone. Both F103L and M106I NS1 mutations significantly enhanced growth in vitro (mouse and canine cells) and in vivo (BALB/c mouse lungs) as well as enhanced virulence in the mouse. Only the M106I NS1 mutation enhanced growth in human cells. Furthermore, these NS1 mutations enhanced early viral protein synthesis in MDCK cells and showed an increased ability to replicate in mouse interferon β (IFN-β) pre-treated mouse cells relative to rPR8-HK-NS-wt NS1. The double mutant, rPR8-HK-NS-F103L + M106I, demonstrated growth attenuation late in infection due to increased IFN-β induction in mouse cells. We then generated a rPR8 virus possessing the A/HK/156/97 NS gene that possesses 103L + 106I, and then rescued the L103F + I106M mutant. The 103L + 106I mutations increased virulence by >10 fold in BALB/c mice. We also inserted the avian A/Ck/Beijing/1/95 NS1 gene (the source lineage of the A/HK/156/97 NS1 gene) that possesses 103L + 106I, onto the A/WSN/33 backbone and then generated the L103F + I106M mutant. None of the H5N1 and H9N2 NS containing viruses resulted in increased IFN-β induction. The rWSN-A/Ck/Beijing/1/95-NS1 gene possessing 103L and 106I demonstrated 100 fold enhanced growth and >10 fold enhanced virulence that was associated with increased tropism for lung alveolar and bronchiolar tissues relative to the corresponding L103F and I106M mutant.

Conclusions

The F103L and M106I NS1 mutations were adaptive genetic determinants of growth and virulence in both human and avian NS1 genes in the mouse model.
Exposure to Diethylstilbestrol During Embryonic and Larval Stages of Medaka Fish (Oryzias latipes) Leads to Sex Reversal in Genetic Males and Reduced Gonad Weight in Genetic Females
Authors: Paul-Prasanth Bindhu , Shibata Yasushi , Horiguchi Ryo , Nagahama Yoshitaka
Published: January 2011

Molecular and cellular mechanisms involved in artificially induced ovarian differentiation were analyzed by exposing embryos of medaka (Oryzias latipes) to a potent nonsteroidal estrogen, diethylstilbestrol (DES). Embryos were exposed for short-exposure (SE) [from 0 to 8 d postfertilization (dpf)] and long-exposure (LE) periods (from 0 to 18/28 dpf) to 1 ng/ml of DES, and status of sexual differentiation in somatic and germ cells of these gonads was analyzed at 8, 18, and 28 dpf by histology, cell proliferation assays, TUNEL assay, and in situ hybridization using sex-specific somatic and germ cell markers. Additionally, gonads of exposed fry were examined after withdrawal of DES to see whether effects of DES in exposed fish were reversible or not. DES induced germ cell proliferation and meiosis in XY fry of SE and LE groups. However, SE induced only a partial reduction in expression of gonadal soma-derived factor, the male-dominant somatic cell marker, and was not sufficient to induce ovarian development after withdrawal of DES. On the contrary, LE resulted in complete loss of such male-specific gene expression in somatic cells of XY gonads, and these gonads underwent sustained ovarian development even after withdrawal of DES. Importantly, LE to DES affected germ cell proliferation in XX gonads adversely during early stages of sexual differentiation, leading to reduced gonad weight in adulthood. Interestingly, apoptosis was not the cause for reduction in germ cell number. Taken together, these results indicated that DES exposure has long-lasting effects on the gonadal development in genetic males (sex reversal) and females (reduced gonad weight) of medaka.
In Vivo Activity of the Thyroid Hormone Receptor β- and α-Selective Agonists GC-24 and CO23 on Rat Liver, Heart, and Brain
Authors: Grijota-Martínez Carmen , Samarut Eric , Scanlan Thomas S. , Morte Beatriz , Bernal Juan
Published: January 2011

Thyroid hormone analogs with selective actions through specific thyroid hormone receptor (TR) subtypes are of great interest. They might offer the possibility of mimicking physiological actions of thyroid hormone with receptor subtype or tissue specificity with therapeutic aims. They are also pharmacological tools to dissect biochemical pathways mediated by specific receptor subtypes, in a complementary way to mouse genetic modifications. In this work, we studied the in vivo activity in developing rats of two thyroid hormone agonists, the TRβ-selective GC-24 and the TRα-selective CO23. Our principal goal was to check whether these compounds were active in the rat brain. Analog activity was assessed by measuring the expression of thyroid hormone target genes in liver, heart, and brain, after administration to hypothyroid rats. GC-24 was very selective for TRβ and lacked activity on the brain. On the other hand, CO23 was active in liver, heart, and brain on genes regulated by either TRα or TRβ. This compound, previously shown to be TRα-selective in tadpoles, displayed no selectivity in the rat in vivo.
Activation of the Cholinergic Antiinflammatory Pathway Ameliorates Obesity-Induced Inflammation and Insulin Resistance
Authors: Wang XianFeng , Yang ZhengGang , Xue Bingzhong , Shi Hang
Published: January 2011

Obesity is associated with a chronic inflammatory state characterized by adipose tissue macrophage infiltration and inflammation, which contributes to insulin resistance. The cholinergic antiinflammatory pathway, which acts through the macrophage α7-nicotinic acetylcholine receptor (α7nAChR), is important in innate immunity. Here we show that adipose tissue possesses a functional cholinergic signaling pathway. Activating this pathway by nicotine in genetically obese (db/db) and diet-induced obese mice significantly improves glucose homeostasis and insulin sensitivity without changes of body weight. This is associated with suppressed adipose tissue inflammation. In addition, macrophages from α7nAChR−/− [α7 knockout (α7KO)] mice have elevated proinflammatory cytokine production in response to free fatty acids and TNFα, known agents causing inflammation and insulin resistance. Nicotine significantly suppressed free fatty acid- and TNFα-induced cytokine production in wild type (WT), but not α7KO macrophages. These data suggest that α7nAChR is important in mediating the antiinflammatory effect of nicotine. Indeed, inactivating this pathway in α7KO mice results in significantly increased adipose tissue infiltration of classically activated M1 macrophages and inflammation in α7KO mice than their WT littermates. As a result, α7KO mice exhibit more severely impaired insulin sensitivity than WT mice without changes of body weight. These data suggest that the cholinergic antiinflammatory pathway plays an important role in obesity-induced inflammation and insulin resistance. Targeting this pathway may provide novel therapeutic benefits in the prevention and treatment of obesity-induced inflammation and insulin resistance.
Premature Ovarian Failure in Mice with Oocytes Lacking Core 1-Derived O-Glycans and Complex N-Glycans
Authors: Williams Suzannah A. , Stanley Pamela
Published: January 2011

Premature ovarian failure (POF) affects up to 1.4% of women under the age of 40 yr and less than 30% of cases have a known cause. Here we describe a new mouse model of POF resulting from oocyte-specific ablation of core 1-derived (mucin) O-glycans and complex and hybrid N-glycans. Females carrying floxed alleles of both the C1galt1 (T-syn) and Mgat1 glycosyltransferase genes and a ZP3Cre transgene, generate oocytes lacking complex O- and N-glycans following oocyte-specific deletion at the primary follicle stage. We previously showed that few double-mutant females are fertile, and those produce only a single small litter. Here we show that ovarian function declined rapidly in double-mutant females with less than 1% ovulating at 11 wk of age after superovulation with exogenous gonadotropins. Ovary weight was significantly decreased in double-mutant females by 3 months of age, consistent with a decrease in the number of developing follicles. FSH levels in double-mutant females were elevated at 3 months of age, and testosterone and inhibin A were decreased, showing that the loss of complex N- and O-glycans from oocyte glycoproteins affected hypothalamic-pituitary-gonadal feedback loops. The absence of developing follicles, ovary dysfunction, reduced testosterone and inhibin A, and elevated FSH in double-mutant females lacking C1galt1 and Mgat1 in oocytes represents a new mouse model for the study of follicular POF.
Gonadotropin-Releasing Hormone-II Increases Membrane Type I Metalloproteinase Production via β-Catenin Signaling in Ovarian Cancer Cells
Authors: Ling Poon Song , Lau Man-Tat , Hammond Geoffrey L. , Leung Peter C. K.
Published: January 2011

GnRH-II is produced by ovarian cancer cells and enhances their invasiveness in vitro. In our studies of OVCAR-3 and CaOV-3 ovarian cancer cell lines, GnRH-II treatment induced phosphorylation of Akt and glycogen synthase kinase (GSK)3β, as well as β-catenin accumulation in the nucleus, and the latter was reduced by small interfering RNA (siRNA)-mediated depletion of the GnRH receptor. The phosphatidylinositol 3 kinase (PI3K)/Akt pathway is involved in β-catenin-dependent signaling, and pretreatment of these human ovarian cancer cells with a PI3K/Akt inhibitor, LY294002, attenuated GnRH-II-stimulated phosphorylation of GSK3β and inhibited GnRH-II-induced invasion. It also attenuated GnRH-II induced trans-activation of a β-catenin-dependent reporter gene, most likely because GSK3β phosphorylation promotes translocation of β-catenin to the nucleus. Membrane type I matrix metalloproteinase (MT1-MMP) contributes to tumor progression directly, or by processing the latent MMP-2 zymogen, and is a known target of β-catenin signaling. When OVCAR-3 and CaOV-3 cells were treated with GnRH-II, MT1-MMP levels increased approximately 3-fold, whereas siRNA-mediated depletion of GnRH receptor or pretreatment with LY294002 abrogated this. In addition, lithium chloride, which increases GSK3β phosphorylation and the nuclear translocation of β-catenin, increased MT1-MMP levels in these ovarian cancer cells. By contrast, depletion of β-catenin by siRNA treatment abolished GnRH-II-induced MT1-MMP synthesis and reduced their invasive potential. Furthermore, siRNA-mediated reduction of MT1-MMP levels reduced GnRH-II-induced invasion in ovarian cancer cells. We therefore conclude that GnRH-II stimulates the PI3K/Akt pathway, and the phosphorylation of GSK3β, thereby enhancing the β-catenin-dependent up-regulation of MT1-MMP production, which contributes to ovarian cancer metastasis.
Reactive Oxygen Species Play an Essential Role in IGF-I Signaling and IGF-I-Induced Myocyte Hypertrophy in C2C12 Myocytes
Authors: Handayaningsih Anastasia-Evi , Iguchi Genzo , Fukuoka Hidenori , Nishizawa Hitoshi , Takahashi Michiko , Yamamoto Masaaki , Herningtyas Elizabeth-Henny , Okimura Yasuhiko , Kaji Hidesuke , Chihara Kazuo , Seino Susumu , Takahashi Yutaka
Published: January 2011

IGF-I induces skeletal muscle hypertrophy by stimulating protein synthesis and suppressing the protein degradation pathway; the downstream signaling pathways Akt-mammalian target of rapamycin (mTOR)-p70-kDA-S6-kinase (p70S6K), and Forkhead box O1 (FoxO1) play essential roles in this regulation. Reactive oxygen species (ROS) modulate the signaling of various growth factors via redox regulation. However, the role of ROS in IGF-I signaling is not fully understood. In this study, we investigated whether ROS regulate the signaling and biological action of IGF-I in C2C12 myocytes. We found that IGF-I induces ROS in C2C12 myocytes. While treatment with H2O2 significantly enhanced IGF-I-induced phosphorylation of the IGF-I receptor (IGF-IR), IGF-IR phosphorylation was markedly attenuated when cells were treated with antioxidants. The downstream signaling pathway, Akt-mTOR-p70S6K was subsequently down-regulated. Furthermore, the phosphorylation of FoxO1 by IGF-I decreased concomitantly with the restoration of the expression of its target genes, Atrogin-1 and muscle RING finger 1, which are related to muscle atrophy. Nox4 knockdown, which is reportedly to produce ROS in insulin signaling, attenuated IGF-I-induced IGF-IR phosphorylation, indicating that Nox4 is involved in the regulation of IGF-I signaling. Importantly, antioxidant treatments inhibited IGF-I-induced myocyte hypertrophy, demonstrating that ROS are necessary for IGF-I-induced myocyte hypertrophy in vitro. These results indicate that ROS play an essential role in the signaling and biological action of IGF-I in C2C12 myocytes.
Changes in Gene Expression during Pituitary Morphogenesis and Organogenesis in the Chick Embryo
Authors: Proszkowiec-Weglarz Monika , Higgins Stacy E. , Porter Tom E.
Published: January 2011

The anterior pituitary gland plays an important role in the regulation of many physiological processes. Formation of Rathke's pouch (RP), the precursor of the anterior pituitary, involves evagination of the oral ectoderm in a multi-step process regulated by cell interactions, signaling pathways, and transcription factors. Chickens are an excellent model to study development because of the availability of large sample sizes, accurate timing of development, and embryo accessibility. The aim of this study was to quantify mRNA expression patterns in the developing chicken anterior pituitary to evaluate the chicken embryo as a model for mammalian pituitary development. The expression profiles of 16 genes differentially expressed in RP and neuroectoderm were determined in this study. Among these, Pitx1, Pitx2, and Hesx1 mRNA levels were high on embryonic days (e) 2.5 to e3 in RP and decreased during development. Expression of Pit1 and Tbx19 mRNA in RP reached the highest levels by e7 and e6.5, respectively. Levels of glycoprotein subunit α mRNA increased beginning at e4. FGF8 mRNA showed the highest expression at e3 to e3.5 in neuroectoderm. BMP2 showed slight decreases in mRNA expression in both tissues during development, while Isl1 and Noggin mRNA expression increased in later development. Taken together, we present the first quantitative transcriptional profile of pituitary organogenesis. Our results will help further understanding of the functional development of this gland. Moreover, because of the high similarity in gene expression patterns observed between chicken and mouse, chickens could serve as an excellent model to study genetic and molecular mechanisms underlying pituitary development.
Aldosterone Production in Human Adrenocortical Cells Is Stimulated by High-Density Lipoprotein 2 (HDL2) through Increased Expression of Aldosterone Synthase (CYP11B2)
Authors: Xing Yewei , Cohen Anthony , Rothblat George , Sankaranarayanan Sandhya , Weibel Ginny , Royer Lori , Francone Omar L. , Rainey William E.
Published: January 2011

Adrenal aldosterone production is regulated by physiological agonists at the level of early and late rate-limiting steps. Numerous studies have focused on the role of lipoproteins including high-density lipoprotein (HDL) as cholesterol providers in this process; however, recent research suggests that HDL can also act as a signaling molecule. Herein, we used the human H295R adrenocortical cell model to study the effects of HDL on adrenal aldosterone production and CYP11B2 expression. HDL, especially HDL2, stimulated aldosterone synthesis by increasing expression of CYP11B2. HDL treatment increased CYP11B2 mRNA in both a concentration- and time-dependent manner, with a maximal 19-fold increase (24 h, 250 μg/ml of HDL). Effects of HDL on CYP11B2 were not additive with natural agonists including angiotensin II or K+. HDL effects were likely mediated by a calcium signaling cascade, because a calcium channel blocker and a calmodulin kinase inhibitor abolished the CYP11B2-stimulating effects. Of the two subfractions of HDL, HDL2 was more potent than HDL3 in stimulating aldosterone and CYP11B2. Further studies are needed to identify the active components of HDL, which regulate aldosterone production.
Hypermethylation of Hepatic Glucokinase and L-Type Pyruvate Kinase Promoters in High-Fat Diet–Induced Obese Rats
Authors: Jiang Minghong , Zhang Yuhao , Liu Meng , Lan Michael Shihli , Fei Jing , Fan Weiwei , Gao Xin , Lu Daru
Published: January 2011

Obesity-dependent insulin resistance and type 2 diabetes mellitus are closely associated with decreased glucose utilization and down-regulation of hepatic glycolytic enzymes expression. Previously, we showed that DNA hypermethylation is involved in age-dependent susceptibility to hepatic insulin resistance and diabetes. However, what we cannot distinguish is whether the age-related obesity contributes to DNA hypermethylation in those natural aging rats. In the present study, we hypothesize that DNA methylation plays a crucial role in the regulation of glycolytic enzymes in the high-fat diet–induced obesity. Here, we report that DNA hypermethylation is correlated with a decline in hepatic glucokinase (Gck) and L-type pyruvate kinase (LPK) expression in high-fat diet–induced obese rats as compared with the control diet group. Down-regulation of Gck and LPK expression are reversed by the 5-aza-2′-deoxycytidine in the cell model of steatosis. These novel observations indicate that DNA methylation is involved in the development of metabolic diseases, such as obesity, insulin resistance, type 2 diabetes mellitus, and nonalcoholic steatohepatitis, suggesting that the hypermethylation level of Gck and LPK promoters may be a useful parameter for the evaluation of obesity-induced insulin resistance and fatty liver.
Kisspeptin Is Essential for the Full Preovulatory LH Surge and Stimulates GnRH Release from the Isolated Ovine Median Eminence
Authors: Smith Jeremy T. , Li Qun , Yap Kai Sing , Shahab Muhammad , Roseweir Antonia K. , Millar Robert P. , Clarke Iain J.
Published: January 2011

Kisspeptins are the product of the Kiss1 gene and potently stimulate GnRH secretion. In sheep, Kiss1 mRNA-expressing cells are found in the arcuate nucleus (ARC) and dorsal-lateral preoptic area and both appear to mediate the positive feedback effect of estradiol to generate the preovulatory GnRH/LH surge. To determine the role of kisspeptin in transmitting estrogen-positive feedback in the hypothalamus, we administered the kisspeptin antagonist p-271 to ewes subjected to an estradiol benzoate-induced LH surge. Kisspeptin antagonist treatment significantly attenuated these LH surges. We further examined the response to kisspeptin treatment prior to the LH surge. Kisspeptin significantly stimulated GnRH secretion into the hypophysial portal system, but the response to kisspeptin was similar in luteal and late-follicular phase ewes. Kiss1r mRNA expression in GnRH neurons was also similar across the estrous cycle. To examine alternative pathways for kisspeptin stimulation of GnRH neurons, we examined the origin of kisspeptin neuronal fibers in the external zone of the median eminence (ME) using neuronal tracing and immunohistochemical techniques. ARC populations of kisspeptin neurons project fibers to the ME. Finally, we showed kisspeptin stimulates GnRH release from ovine ME-cultured explants. This suggests direct kisspeptin to GnRH terminal-to-terminal communication within the ME. Overall, these data indicate an essential role for kisspeptin in receiving stimulatory estrogen signals and generating the full positive feedback GnRH/LH surge. Kisspeptin neurons of the ARC project to the external zone of the ME and kisspeptin acts upon the GnRH fibers at this level.
Corticosteroid Regulation of P-Glycoprotein in the Developing Blood-Brain Barrier
Authors: Iqbal Majid , Gibb William , Matthews Stephen G.
Published: January 2011

The early fetal brain is susceptible to teratogens in the maternal circulation, because brain microvessel expression of drug efflux transporter, P-glycoprotein (P-gp), is very low. However, there is a dramatic up-regulation of brain microvessel P-gp in late gestation. This study investigated the role of cortisol and dexamethasone in this up-regulation of fetal brain microvessel P-gp expression. Primary brain endothelial cell (BEC) cultures derived from gestational d (GD)40, GD50, GD65 (term, ∼68 d) and postnatal d 14 male guinea pigs were treated with varying doses (10−8 to 10−5m) of cortisol, dexamethasone, and aldosterone. After treatment, P-gp function was assessed using calcein-acetoxymethyl ester (P-gp substrate; 1 μm for 1 h) and measuring BEC accumulation of calcein. Corticosteroid treatment of BECs derived from postnatal d 14 resulted in increased P-gp activity. BECs derived from GD65 (near term) responded similarly, but these cells were extremely sensitive to the effects of mineralocorticoid receptor agonists (cortisol and aldosterone). BECs derived from GD50 displayed dose-dependent increases in P-gp function with dexamethasone (P < 0.05) and a trend towards increased function with cortisol. Cells derived from GD40 were unresponsive to all treatments. In conclusion, P-gp function in BECs is more responsive to glucocorticoids (GCs) in late gestation. Therefore, the late gestational surge in fetal plasma GCs, which parallels the increase in brain microvessel P-gp expression, may contribute to this P-gp up-regulation. Further, synthetic GCs (administered to pregnant women at risk of preterm delivery) may increase the protective capacity of the developing fetal blood-brain barrier, depending on the timing of GC exposure.
Surgical Results of Thyroid Nodules according to a Management Guideline Based on the BRAFV600E Mutation Status
Authors: Kim Suk Kyeong , Hwang Tae Sook , Yoo Young Bum , Han Hye Seung , Kim Dong-Lim , Song Kee-Ho , Lim So Duk , Kim Wan Seop , Paik Nam Sun
Published: January 2011

Context:

In Korea, where PTC comprises about 90–95% of the reported thyroid cancers, the prevalence of BRAFV600E mutation in papillary thyroid carcinoma (PTC) is above 80%.

Objective:

We analyzed the surgical result according to a management guideline based on the BRAFV600E mutation status of thyroid nodules.

Design:

A total of 865 thyroid nodules were prospectively analyzed for their cytology and BRAFV600E mutation status by pyrosequencing. For the patients who had a diagnosis of atypical cells of undetermined significance (ACUS), we recommended surgery when there was positivity for BRAFV600E mutation or the nodules were clinically suspicious.

Results:

Among 865 cases, 504, 141, 54, 140, 10, and 16 were diagnosed as benign, ACUS, suspicious for malignancy, malignant, suspicious for follicular neoplasm, and nondiagnostic, respectively. None of the 504 benign, 45 (31.9%) of the 141 ACUS, 46 (85.2%) of the 54 suspicious for malignancy, 129 (92.1%) of the 140 malignant, and one (10%) of the 10 suspicious for follicular neoplasm cases showed BRAFV600E mutation. Surgery was recommended to all 45 patients with BRAFV600E mutation-positive ACUS nodules; among them, 30 patients underwent surgery, 29 had PTC, and one had nodular hyperplasia. All the patients diagnosed as suspicious for malignancy or malignant were advised to undergo an operation, and they turned out to have PTCs regardless of their BRAFV600E mutation status.

Conclusions:

We found that performing BRAFV600E mutation analysis on the fine-needle aspiration biopsy specimens was of great help to make a therapeutic decision for thyroid nodules when the fine-needle aspiration biopsy results were equivocal.
SHBG, Sex Hormones, and Inflammatory Markers in Older Women
Authors: Maggio Marcello , Ceda Gian Paolo , Lauretani Fulvio , Bandinelli Stefania , Corsi Anna Maria , Giallauria Francesco , Guralnik Jack M. , Zuliani Giovanni , Cattabiani Chiara , Parrino Stefano , Ablondi Fabrizio , Dall'Aglio Elisabetta , Ceresini Graziano , Basaria Shehzad , Ferrucci Luigi
Published: January 2011

Context:

In premenopausal and older women, high testosterone and estradiol (E2) and low SHBG levels are associated with insulin resistance and diabetes, conditions characterized by low-grade inflammation.

Objective:

The aim of the study was to examine the relationship between SHBG, total testosterone, total E2, and inflammatory markers in older women.

Design and Patients:

We conducted a retrospective cross-sectional study of 433 women at least 65 yr old from the InCHIANTI Study, Italy, who were not on hormone replacement therapy or recently hospitalized and who had complete data on SHBG, testosterone, E2, C-reactive protein (CRP), IL-6, soluble IL-6 receptor (sIL-6r), and TNF-α. Relationships between sex hormones and inflammatory markers were examined by multivariate linear regression analyses adjusted for age, body mass index, smoking, insulin, physical activity, and chronic disease.

Results:

In fully adjusted analyses, SHBG was negatively associated with CRP (P = 0.007), IL-6 (P = 0.008), and sIL-6r (P = 0.02). In addition, testosterone was positively associated with CRP (P = 0.006), IL-6 (P = 0.001), and TNF-α (P = 0.0002). The negative relationship between testosterone and sIL-6r in an age-adjusted model (P = 0.02) was no longer significant in a fully adjusted model (P = 0.12). E2 was positively associated with CRP (P = 0.002) but not with IL-6 in fully adjusted models. In a final model including E2, testosterone, and SHBG, and all the confounders previously considered, SHBG (0.23 ± 0.08; P = 0.006) and E2 (0.21 ± 0.08; P = 0.007), but not testosterone (P = 0.21), were still significantly associated with CRP.

Conclusion:

In late postmenopausal women not on hormone replacement therapy, SHBG and E2 are, respectively, negative and positive, independent and significant correlates of a proinflammatory state.
Interaction between Testosterone and Growth Hormone on Whole-Body Protein Anabolism Occurs in the Liver
Authors: Birzniece Vita , Meinhardt Udo J. , Umpleby Margot A. , Handelsman David J. , Ho Ken K. Y.
Published: January 2011

Context:

GH and testosterone both exert protein-anabolic effects and may act synergistically. Liver and muscle are major sites of protein metabolism.

Objective:

Our objective was to determine whether the site of GH and testosterone interaction on protein metabolism is primarily hepatic or extrahepatic.

Design:

In this open-label randomized crossover study, the impact on whole-body protein metabolism of oral (solely hepatic testosterone exposure) and transdermal (systemic testosterone exposure) testosterone replacement in the presence or absence of GH was compared.

Patients and Intervention:

Eleven hypopituitary men with GH and testosterone deficiency were randomized to 2-wk treatments with transdermal testosterone (10 mg) or oral testosterone (40 mg), with or without GH replacement (0.6 mg/d). The dose of testosterone administered orally achieves physiological portal testosterone concentrations without spillover into the systemic circulation.

Main Outcome Measures:

Whole-body leucine turnover was measured, from which leucine rate of appearance (LRa), an index of protein breakdown, and leucine oxidation (Lox), a measure of irreversible protein loss, were estimated at the end of each treatment.

Results:

In the absence of GH, neither transdermal nor oral testosterone affected LRa or Lox. GH therapy significantly increased LRa, an effect equally reduced by transdermal and oral testosterone administration. GH replacement alone did not significantly change Lox, whereas addition of testosterone treatment reduced Lox, with the effect not significantly different between transdermal and oral testosterone.

Conclusions:

In the doses used, testosterone stimulates protein anabolism by reducing protein breakdown and oxidation only in the presence of GH. Because the net effect on protein metabolism during GH therapy is not different between systemic and solely hepatic testosterone administration, we conclude that the liver is the primary site of this hormonal interaction.
Role of Reactive Oxygen Species in Injury-Induced Insulin Resistance
Authors: Zhai Lidong , Ballinger Scott W. , Messina Joseph L.
Published: January 2011

Acute insulin resistance is common after injury, infection, and critical illness. To investigate the role of reactive oxygen species (ROS) in critical illness diabetes, we measured hepatic ROS, which rapidly increased in mouse liver. Overexpression of superoxide dismutase 2, which decreased mitochondrial ROS levels, protected mice from the development of acute hepatic insulin resistance. Insulin-induced intracellular signaling was dramatically decreased, and cellular stress signaling was rapidly increased after injury, resulting in the hyperglycemia of critical illness diabetes. Insulin-induced intracellular signaling, activation of stress (c-Jun N-terminal kinase) signaling, and glucose metabolism were all normalized by superoxide dismutase 2 overexpression or by pretreatment with antioxidants. Thus, ROS play an important role in the development of acute hepatic insulin resistance and activation of stress signaling after injury.
Nr4a1 siRNA Expression Attenuates α-MSH Regulated Gene Expression in 3T3-L1 Adipocytes
Authors: Wang S.-C. Mary , Myers Stephen A. , Eriksson Natalie A. , Fitzsimmons Rebecca L. , Muscat George E. O.
Published: January 2011

Several recent investigations have underscored the growing role of melanocortin signaling in the peripheral regulation of lipid, glucose, and energy homeostasis. In addition, the melanocortins play a critical role in the central control of satiety. These observations, and the latest reports highlighting the emerging role of the nuclear hormone receptor (NR) 4A subgroup in metabolism, have prompted us to investigate the cross talk between [Nle4, d-Phe7] (NDP)-α-MSH and Nr4a signaling in adipose. We have shown that NDP-MSH strikingly and preferentially induces the expression of the NR4A subgroup (but not any other members of the NR superfamily) in differentiated 3T3-L1 adipocytes. Utilization of quantitative PCR on custom-designed metabolic TaqMan low-density arrays identified the concomitant and marked induction of the mRNAs encoding Il-6, Cox2, Pdk4, and Pck-1 after NDP-MSH treatment. Similar experiments demonstrated that the mRNA expression profile induced by cAMP and NDP-MSH treatment displayed unique but also overlapping properties and suggested that melanocortin-mediated induction of gene expression involves cAMP-dependent and -independent signaling. Nr4a1/Nur77 small interfering RNA (siRNA) expression suppressed NDP-MSH-mediated induction of Nr4a1/Nur77 and Nr4a3/Nor-1 (but not Nr4a2/Nurr1). Moreover, expression of the siRNA-attenuated NDP-MSH mediated induction of the mRNAs encoding Il-6, Cox2/Ptgs2, and Pck-1 expression. In addition, Nur77 siRNA expression attenuated NDP-MSH-mediated glucose uptake. In vivo, ip administration of NDP-MSH to C57 BL/6J (male) mice significantly induced the expression of the mRNA encoding Nur77 and increased IL-6, Cox2, Pck1, and Pdk4 mRNA expression in (inguinal) adipose tissue. We conclude that Nur77 expression is necessary for MSH-mediated induction of gene expression in differentiated adipocytes. Furthermore, this study demonstrates cross talk between MSH and Nr4a signaling in adipocytes.
Glucocorticoid-Mediated Repression of the Oncogenic microRNA Cluster miR-17∼92 Contributes to the Induction of Bim and Initiation of Apoptosis
Authors: Molitoris Jason K. , McColl Karen S. , Distelhorst Clark W.
Published: January 2011

Synthetic glucocorticoids were one of the first effective treatments for lymphoid malignancies because of their ability to induce apoptosis and are still used in combination with other chemotherapeutic agents. Up-regulation of Bim, a proapoptotic member of the B-cell lymphoma-2 family, is an important mediator of glucocorticoid-induced apoptosis. Although glucocorticoids are known to elevate Bim mRNA and protein, little is known about the mechanism. Here, we report that glucocorticoids repress the expression of the microRNA cluster miR-17∼92, which results in elevated Bim protein expression as a mechanism by which glucocorticoids induce Bim. Using a luciferase-Bim 3′ untranslated region construct, we demonstrate that glucocorticoids mediate Bim induction posttranscriptionally after miR-17∼92 repression, resulting in increased Bim protein expression. Overexpression of miR-17∼92 microRNAs decreases Bim induction and attenuates glucocorticoid-mediated apoptosis. Conversely, knockdown of miR-17∼92 increases Bim protein expression and glucocorticoid-mediated apoptosis. These findings indicate that endogenous levels of miR-17∼92 repress Bim expression in T-cell lymphoid malignancies and that glucocorticoids induce Bim expression via down-regulation of the miR-17∼92 microRNA cluster. Our findings present a novel mechanism that contributes to the up-regulation of Bim and induction of apoptosis in lymphocytes after glucocorticoid treatment. Furthermore, our work demonstrating that inhibition of miR-17∼92 increases glucocorticoid-induced apoptosis highlights the potential importance of miR-17∼92 as a therapeutic target in leukemias and lymphomas.
Aurora Kinase B Activity Is Modulated by Thyroid Hormone during Transcriptional Activation of Pituitary Genes
Authors: Tardáguila Manuel , González-Gugel Elena , Sánchez-Pacheco Aurora
Published: January 2011

Covalent histone modifications clearly play an essential role in ligand-dependent transcriptional regulation by nuclear receptors. One of the predominant mechanisms used by nuclear receptors to activate or repress target-gene transcription is the recruitment of coregulatory factors capable of covalently modify the amino terminal ends of histones. Here we show that the thyroid hormone (T3) produces a rapid increase in histone H3Ser10 phosphorylation (H3Ser10ph) concomitant to the rapid displacement of the heterochromatin protein 1β (HP1β) to the nuclear periphery. Moreover, we found that T3-mediated pituitary gene transcription is associated with an increase in H3Ser10ph. Interestingly, the Aurora kinase B inhibitor ZM443979 abolishes the effect of T3 on H3Ser10ph, blocks HP1β delocalization, and significantly reduces ligand-dependent transactivation. Similar effects were shown when Aurora kinase B expression was abrogated in small interfering RNA assays. In an effort to understand the underlying mechanism by which T3 increases H3Ser10ph, we demonstrate that liganded thyroid hormone receptor directly interacts with Aurora kinase B, increasing its kinase activity. Moreover, using chromatin immunoprecipitation assays, we have shown that Aurora kinase B participates of a mechanism that displaces HP1β from promoter region, thus preparing the chromatin for the transcriptional activation of T3 regulated genes. Our findings reveal a novel role for Aurora kinase B during transcriptional initiation in GO/G1, apart from its well-known mitotic activity.
Use of a simple arm-raising test with a portable laser Doppler blood flow meter to detect dehydration
Authors: Nogami H , Iwasaki W , Abe T , Kimura Y , Onoe A , Higurashi E , Takeuchi S , Kido M , Furue M , Sawada R
Published: January 2011

Using micro electromechanical systems (MEMS) technologies, the authors have developed the world’s smallest, lightest, and least power-consuming laser Doppler blood flow meter. Unlike commercial fibre-type blood flow instruments, the new blood flow meter is invulnerable to any movements of the person wearing it and has a wireless transmitter. Utilizing the characteristics of the blood flow meter, the authors attempted to detect dehydration by having a subject simply raise an arm (arm-raising test) with the flow meter attached to a fingertip. Healthy young volunteers (20 men and two women, mean age 22.9, age range 21–27 years) were instructed to perspire in a sauna until they became dehydrated. The target dewatering ratio was 2 per cent, which was calculated from the body weight measured using a weight scale. Four markers were compared: mean blood flow (MBF) before arm-raising, MBF during arm-raising, maximum amplitude (MA) of the pulse wave during arm-raising, and inclination of reflex (IR) wave calculated from the recorded blood flow data for the non-dehydrated (before sauna) and dehydrated (3 h after sauna) states in the arm-raising test. Each of the mean total markers (MBF during arm-raising, MA, and IR) was significantly lower ( P < 0.05) during the dehydrated state than the non-dehydrated. These results suggest that three markers could detect dehydration and the blood flow meter devised has the potential to be used as a portable device for detecting dehydration.
Surface Hardening of an AISI D6 Cold Work Steel Using a Fiber Laser
Authors: Goia Flavia Aline , de Lima Milton Sergio Fernandes
Published: January 2011

Laser surface treatments represent some of the most advanced and versatile processes for enhanced materials applications. Laser hardening is a technique to generate a hard wear-resistant surface microstructure in metals due to the rapid heating and cooling cycles imposed by a laser beam. This work intends to understand the influence of the laser variables on hardness after laser hardening of an AISI D6 steel. A fiber laser, which is a new source available for industrial applications, has been used. The overall absorptivity measured was ∼37 % and the laser treatment produced two different zones: Remelted and heat-affected. The surface layer was remelted and composed of martensite and retained austenite. The region next to the free surface is composed of primary austenite dendrites with martensite plates with hardness between 400 and 500 HV. The region called the heat-affect zone is composed of martensite, retained austenite, and carbides and has a hardness up to 800 HV. The case depth in laser treated samples was between 1 and 2 mm.
Controlling Condensation Through the Use of Active and Passive Glazing Systems
Authors: Dunlap Andrew A. , Johnson Paul G. , Songer Curt A.
Published: January 2011

Special building occupancies, those with a high interior relative humidity, have a specific set of performance requirements to control condensation for exterior window and curtain wall systems. High levels of humidity, if not properly accommodated by glazed exterior wall systems, can result in condensation on and within glazing systems and adjacent construction. The performance of glazing has typically been viewed and analyzed based on overall system performance that generally results in a set of values that do not apply to project specific applications. With this approach, important aspects of a system, as applied to specific buildings, are often overlooked. In this circumstance, the result too often is unacceptable levels of condensation. Unfortunately, many within the design, manufacture, and construction communities do not fully understand the importance of treating each building for the unique set of conditions that it is, and the resultant consequence of not analyzing and treating each humidified building as a unique set of materials, systems, and environmental conditions. Similarly, the analysis methods and tools necessary to predict and prevent condensation are even less familiar within the design and construction industry. As a result, deficient systems and materials may often be installed in these applications, resulting in failures ranging from minor inconvenience to complete loss of service. There are, however, methods that can be used to reduce or eliminate such problems. This paper describes methods and procedures that can be utilized to understand and identify the performance levels required for high humidity spaces and analysis methods (including computer modeling) to predict performance of systems and materials, and this paper also describes both active and passive technologies that have been successful in meeting these needs. Passive design, through the use of high performance glazing, and active technologies, such as heat tracing and heated glass, are considered. Benefits, risks, and appropriate uses of each are identified. Examples are included to illustrate these approaches.
Deletion of ERK1 and ERK2 in the CNS Causes Cortical Abnormalities and Neonatal Lethality:Erk1Deficiency Enhances the Impairment of Neurogenesis inErk2-Deficient Mice
Authors: Satoh Yasushi , Kobayashi Yasushi , Takeuchi Atsuya , Pagès Gilles , Pouysségur Jacques , Kazama Tomiei
Published: January 2011

Intracellular signaling through extracellular signal-regulated kinase (ERK) is important in regulating cellular functions in a variety of tissues including the CNS. Although ERK1 and ERK2 have a very similar substrate profile and amino acid sequences, there are strikingly different phenotypes betweenErk1- andErk2-deficient mice. Thus, the question arose as to whether these two proteins are functional homologs that compensate for each other, or whether they have distinct functions. Here, we generated double knock-out mice deficient forErk2in the CNS, with ubiquitous homozygous deletion ofErk1, and compared the phenotypes of these mice with those of monogenicErk2-deficient mice. Although we did obtain double knock-out newborn pups, they survived for not >1 d. These pups appeared normal just after parturition. However, they had no milk in their stomachs even 6–7 h after birth. Intracerebral hemorrhages with varying location and severity were observed. The ventricular zones and corpus callosum of the double knock-out pups did not develop adequately. Neuronal size and nuclear morphology in some brain regions were markedly aberrant in the double knock-out pups compared with controls, while deficiency inErk2only caused a mild phenotype. These results suggest that total ERK1/2 activity governs cellular behaviors to ensure proper brain development.