Veterans Affairs Research Service

Denver, CO, United States

Veterans Affairs Research Service

Denver, CO, United States
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Reuss S.,Johannes Gutenberg University Mainz | Banica O.,Johannes Gutenberg University Mainz | Elgurt M.,Johannes Gutenberg University Mainz | Mitz S.,Johannes Gutenberg University Mainz | And 10 more authors.
Molecular Neurobiology | Year: 2016

The energy-yielding pathways that provide the large amounts of metabolic energy required by inner ear sensorineural cells are poorly understood. Neuroglobin (Ngb) is a neuron-specific hemoprotein of the globin family, which is suggested to be involved in oxidative energy metabolism. Here, we present quantitative real-time reverse transcription PCR, in situ hybridization, immunohistochemical, and Western blot evidence that neuroglobin is highly expressed in the mouse and rat cochlea. For primary cochlea neurons, Ngb expression is limited to the subpopulation of type I spiral ganglion cells, those which innervate inner hair cells, while the subpopulation of type II spiral ganglion cells which innervate the outer hair cells do not express Ngb. We further investigated Ngb distribution in rat, mouse, and human auditory brainstem centers, and found that the cochlear nuclei and superior olivary complex (SOC) also express considerable amounts of Ngb. Notably, the majority of olivocochlear neurons, those which provide efferent innervation of outer hair cells as identified by neuronal tract tracing, were Ngb-immunoreactive. We also observed that neuroglobin in the SOC frequently co-localized with neuronal nitric oxide synthase, the enzyme responsible for nitric oxide production. Our findings suggest that neuroglobin is well positioned to play an important physiologic role in the oxygen homeostasis of the peripheral and central auditory nervous system, and provides the first evidence that Ngb signal differentiates the central projections of the inner and outer hair cells. © 2015, Springer Science+Business Media New York.

Ortmeyer H.K.,University of Maryland Baltimore County | Ortmeyer H.K.,Baltimore Veterans Affairs Medical Center Geriatric Research | Goldberg A.P.,University of Maryland Baltimore County | Goldberg A.P.,Baltimore Veterans Affairs Medical Center Geriatric Research | And 3 more authors.
Obesity | Year: 2017

Objective: The effects of 6-month weight loss (WL) versus aerobic exercise training (AEX)+WL on fat and skeletal muscle markers of fatty acid metabolism were determined in normal (NGT) and impaired (IGT) glucose tolerant African-American and Caucasian postmenopausal women with overweight/obesity. Methods: Fat (gluteal and abdominal) lipoprotein lipase (LPL), skeletal muscle LPL, acyl-CoA synthase (ACS), ß-hydroxacyl-CoA dehydrogenase, carnitine palmitoyltransferase (CPT-1), and citrate synthase (CS) activities were measured at baseline (n = 104) and before and after WL (n = 34) and AEX+WL (n = 37). Results: After controlling for age and race, muscle LPL and CPT-1 were lower in IGT, and the ratios of fat/muscle LPL activity were higher in IGT compared to NGT. Muscle LPL was related to insulin sensitivity (M value) and inversely related to G120, fasting insulin, and homeostatic model assessment of insulin resistance. AEX+WL decreased abdominal fat LPL and increased muscle LPL, ACS, and CS. The ratios of fat/muscle LPL decreased after AEX+WL. The change in VO2max was related to the changes in LPL, ACS, and CS and inversely related to the changes in fat/muscle LPL activity ratios. Conclusions: Six-month AEX+WL, and not WL alone, is capable of enhancing skeletal muscle fatty acid metabolism in postmenopausal African-American and Caucasian women with NGT, IGT, and overweight/obesity. © 2017 The Obesity Society

Wierman M.E.,Aurora University | Wierman M.E.,Veterans Affairs Research Service | Arlt W.,University of Birmingham | Basson R.,University of British Columbia | And 6 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2014

Conclusions: We continue to recommend against making a diagnosis of and rogen deficiency syndrome in healthy women because there is a lack of a well-defined syndrome, and data correlating and rogen levels with specific signs or symptoms are unavailable. We recommend against the general use of T for the following indications: infertility; sexual dysfunction other than hypoactive sexual desire disorder; cognitive, cardiovascular, metabolic, or bone health; or general well-being. We recommend against the routine use of dehydroepi and rosterone due to limited data concerning its effectiveness and safety in normal women or those with adrenal insufficiency. Were commend against ther out in eprescription of Tordehydroepi and rosterone for the treatment of women with low and rogen levels due to hypopituitarism, adrenal insufficiency, surgical menopause, pharmacological glucocorticoid administration, or other conditions associated with low and rogen levels because there are limited data supporting improvement in signs and symptoms with therapy and no long-term studies of risk. Evidence supports the short-term efficacy and safety of high physiological doses of T treatment of postmenopausal women with sexual dysfunction due to hypoactive sexual desire disorder. Importantly, endogenous T levels did not predict response to therapy. At present, physiological T preparations for use in women are not available in many countries including the United States, and long-term safety data are lacking. We recommend that any woman receiving T therapy be monitored for signs and symptoms of and rogen excess. We outline areas for future research. Ongoing improvement in and rogen assays will allow a redefinition of normal ranges across the lifespan; this may help to clarify the impact of varying concentrations of plasma androgens on the biology, physiology, and psychology in women and lead to indications for therapeutic interventions.Participants: A Task Force appointed by the Endocrine Society, American Congress of Obestricians and Gynecologists (ACOG), American Society for Reproductive Medicine (ASRM), European Society of Endocrinology (ESE), and International Menopause Society (IMS) consisting of six experts, a methodologist, and a medical writer.Objective: To update practice guidelines for the therapeutic use of androgens in women.Evidence: The Task Force commissioned two systematic reviews of published data and considered several other existing meta-analyses and trials. The GRADE methodology was used; the strength of a recommendation is indicated by a number "1" (strong recommendation, we recommend) or "2" (weak recommendation, we suggest).Consensus Process: Multiple e-mail communications and conference calls determined consensus. Committees of the Endocrine Society, ASRM, ACOG, ESE, and IMS reviewed and commentedonthe drafts of the guidelines. Copyright © 2014 by the Endocrine Society.

Reidelberger R.,Veterans Affairs Research Service | Reidelberger R.,Creighton University | Haver A.,Veterans Affairs Research Service | Haver A.,Creighton University | And 2 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2014

Cholecystokinin (CCK)-induced suppression of feeding is mediated by vagal sensory neurons that are destroyed by the neurotoxin capsaicin (CAP). Here we determined whether CAP-sensitive neurons mediate anorexic responses to intravenous infusions of gut hormones peptide YY-(3–36) [PYY-(3–36)] and glucagon-like peptide-1 (GLP-1). Rats received three intraperitoneal injections of CAP or vehicle (VEH) in 24 h. After recovery, non-food-deprived rats received at dark onset a 3-h intravenous infusion of CCK-8 (5, 17 pmol·kg−1·min−1), PYY-(3–36) (5, 17, 50 pmol·kg−1·min−1), or GLP-1 (17, 50 pmol·kg−1·min−1). CCK-8 was much less effective in reducing food intake in CAP vs. VEH rats. CCK-8 at 5 and 17 pmol·kg−1·min−1 reduced food intake during the 3-h infusion period by 39 and 71% in VEH rats and 7 and 18% in CAP rats. In contrast, PYY-(3–36) and GLP-1 were similarly effective in reducing food intake in VEH and CAP rats. PYY-(3–36) at 5, 17, and 50 pmol·kg−1·min−1 reduced food intake during the 3-h infusion period by 15, 33, and 70% in VEH rats and 13, 30, and 33% in CAP rats. GLP-1 at 17 and 50 pmol·kg−1·min−1 reduced food intake during the 3-h infusion period by 48 and 60% in VEH rats and 30 and 52% in CAP rats. These results suggest that anorexic responses to PYY-(3–36) and GLP-1 are not primarily mediated by the CAP-sensitive peripheral sensory neurons (presumably vagal) that mediate CCK-8-induced anorexia. © 2014 The American Physiological Society.

Reidelberger R.,Veterans Affairs Research Service | Reidelberger R.,Creighton University | Haver A.,Veterans Affairs Research Service | Haver A.,Creighton University | And 2 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2013

Peptide YY(3-36) [PYY(3-36)] is postulated to act as a hormonal signal from gut to brain to inhibit food intake. PYY(3-36) potently reduces food intake when administered systemically or into the brain. If action of endogenous PYY(3-36) is necessary for normal satiation to occur, then pharmacological blockade of its receptors should increase food intake. Here, we determined the effects of iv infusion of Y1, Y2, and Y5 receptor antagonists (BIBP 3226, BIIE 0246, CGP 71683) during the first 3 h of the dark period on food intake in non-food-deprived rats. Our results showed that 1) Y2 receptor blockade reversed the anorexic response to iv infusion of PYY(3-36) but did not increase food intake when administered alone; 2) Y1 and Y5 receptor antagonists neither attenuated PYY(3-36)-induced anorexia nor altered food intake when given alone; and 3) Y2 receptor blockade attenuated anorexic responses to gastric infusions of casein hydrolysate and long-chain triglycerides, but not maltodextrin. Previous work showed that Y2 antagonist BIIE 0246 does not penetrate the blood-brain barrier. Together, these results support the hypothesis that gut PYY(3-36) action at Y2 receptors peripheral to the blood brain barrier plays an essential role in mediating satiety responses to gastric delivery of protein and long-chain triglycerides, but not polysaccharide. © 2013 the American Physiological Society.

Reidelberger R.,Veterans Affairs Research Service | Reidelberger R.,Creighton University | Haver A.,Veterans Affairs Research Service | Haver A.,Creighton University | And 8 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2012

Weight loss in obese humans produces a relative leptin deficiency, which is postulated to activate potent orexigenic and energy conservation mechanisms to restrict weight loss and promote weight regain. Here we determined whether leptin replacement alone or with GLP-1 receptor agonist exendin-4 attenuates weight regain or promotes greater weight loss in weight-reduced diet-induced obese (DIO) rats. Forty percent restriction in daily intake of a high-fat diet in DIO rats for 4 wk reduced body weight by 12%, body fat by 29%, and plasma leptin by 67% and normalized leptin sensitivity. When food restriction ended, body weight, body fat, and plasma leptin increased rapidly. Daily administration of leptin [3-h intraperitoneal (ip) infusions (4 nmol·kg _1·h -1)] at onset and end of dark period for 3 wk did not attenuate hyperphagia and weight regain, nor did it affect mean daily meal sizes or meal numbers. Exendin-4 (50 pmol·kg _1·h _1) infusions during the same intervals prevented postrestriction hyperphagia and weight regain by normalizing meal size. Coadministration of leptin and exendin-4 did not reduce body weight more than exendin-4 alone. Instead, leptin began to attenuate the inhibitory effects of exendin-4 on food intake, meal size, and weight regain by the end of the second week of administration. Plasma leptin in rats receiving leptin was sevenfold greater than in rats receiving vehicle and 17-fold greater than in rats receiving exendin-4. Together, these results do not support the hypothesis that leptin replacement alone or with exendin-4 attenuates weight regain or promotes greater weight loss in weight-reduced DIO rats. © 2012 the American Physiological Society.

Ntumngia F.B.,University of South Florida | King C.L.,Veterans Affairs Research Service | King C.L.,Case Western Reserve University | Adams J.H.,University of South Florida
International Journal for Parasitology | Year: 2012

Plasmodium vivax Duffy binding protein region II (DBPII) is an essential ligand for reticulocyte invasion, thereby making this molecule an attractive vaccine candidate against asexual blood-stage P. vivax. Similar to other Plasmodium blood-stage vaccine candidates, strain-specific immunity due to DBPII allelic variation may complicate vaccine efficacy. Targeting immune responses to more conserved epitopes that are potential targets of strain-transcending neutralising immunity is necessary to avoid induction of strain-specific responses to dominant variant epitopes. In this article, we focus on different approaches to optimise the design of DBP immunogenicity to target conserved epitopes, which is important for developing a broadly effective vaccine against P. vivax. © 2012 Australian Society for Parasitology Inc.

Menard D.,Institute Pasteur Of Madagascar | Menard D.,Institute Pasteur Paris | Barnadas C.,Institute Pasteur Of Madagascar | Barnadas C.,Case Western Reserve University | And 15 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

Malaria therapy, experimental, and epidemiological studies have shown that erythrocyte Duffy blood group-negative people, largely of African ancestry, are resistant to erythrocyte Plasmodium vivax infection. These findings established a paradigm that the Duffy antigen is requiredfor P. vivax erythrocyte invasion. P. vivax is endemic in Madagascar, where admixture of Duffy-negative and Duffy-positive populations of diverse ethnic backgrounds has occurred over 2 millennia. There, we investigated susceptibility to P. vivax blood-stage infection and disease in association with Duffy blood group polymorphism. Duffy blood group genotyping identified 72% Duffy-negative individuals (FY*BES/*BES) in community surveys conducted at eight sentinel sites. Flow cytometry and adsorption-elution results confirmed the absence of Duffy antigen expression on Duffy-negative erythrocytes. P. vivax PCR positivity was observed in 8.8% (42/476) of asymptomatic Duffy-negative people. Clinical vivax malaria was identified in Duffy-negative subjects with nine P. vivax monoinfections and eight mixed Plasmodium species infections that included P. vivax (4.9 and 4.4% of 183 participants, respectively). Microscopy examination of blood smears confirmed blood-stage development of P. vivax, including gametocytes. Genotyping of polymorphic surface and microsatellite markers suggested that multiple P. vivax strains were infecting Duffy-negative people. In Madagascar, P. vivax has broken through its dependence on the Duffy antigen for establishing human blood-stage infection and disease. Further studies are necessary to identify the parasite and host molecules that enable this Duffy-independent P. vivax invasion of human erythrocytes.

Siddiqui A.A.,Case Western Reserve University | Xainli J.,Case Western Reserve University | Schloegel J.,University of South Florida | Carias L.,Case Western Reserve University | And 7 more authors.
Infection and Immunity | Year: 2012

Plasmodium vivax invasion of human erythrocytes requires interaction of the P. vivax Duffy binding protein (PvDBP) with its host receptor, the Duffy antigen (Fy) on the erythrocyte surface. Consequently, PvDBP is a leading vaccine candidate. The binding domain of PvDBP lies in a cysteine-rich portion of the molecule called region II (PvDBPII). PvDBPII contains three distinct subdomains based upon intramolecular disulfide bonding patterns. Subdomain 2 (SD2) is highly polymorphic and is thought to contain many key residues for binding to Fy, while SD1 and SD3 are comparatively conserved and their role in Fy binding is not well understood. To examine the relative contributions of the different subdomains to binding to Fy and their abilities to elicit strain-transcending binding-inhibitory antibodies, we evaluated recombinant proteins from SD1+2, SD2, SD3, and SD3+, which includes 24 residues of SD2. All of the recombinant subdomains, except for SD2, bound variably to human erythrocytes, with constructs containing SD3 showing the best binding. Antisera raised in laboratory animals against SD3, SD3+, and SD2+3 inhibited the binding of full-length PvDBPII, which is strain transcending, whereas antisera generated to SD1+2 and SD2 failed to generate blocking antibodies. All of the murine monoclonal antibodies generated to full-length PvDBPII that had significant binding-inhibitory activity recognized only SD3. Thus, SD3 binds Fy and elicits blocking antibodies, indicating that it contains residues critical to Fy binding that could be the basis of a strain-transcending candidate vaccine against P. vivax. © 2012, American Society for Microbiology.

Salian-Mehta S.,Aurora University | Xu M.,Aurora University | Knox A.J.,Aurora University | Plummer L.,Massachusetts General Hospital | And 7 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2014

Context: Prior studies showed that Axl /Tyro3 null mice have delayed first estrus and abnormal cyclicity due to developmental defects in GnRH neuron migration and survival. Objective: The objective of the study was to test whether the absence of Axl would alter reproductive function in mice and that mutations inAXLare present in patients with Kallmann syndrome (KS) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH). Design and Setting: The sexual maturation of Axl null mice was examined. The coding region of AXL was sequenced in 104 unrelated, carefully phenotyped KS or nIHH subjects. Frequency of mutations was compared with other causes of GnRH deficiency. Functional assays were performed on the detected mutations. Results: Axl null mice demonstrated delay in first estrus and the interval between vaginal opening and first estrus. Three missense AXL mutations (p.L50F, p.S202C, and p.Q361P) and one intronic variant 6 bp upstream from the start of exon 5 (c.586-6 C>T) were identified in two KS and 2 two nIHH subjects. Comparison of the frequencies of AXL mutations with other putative causes of idiopathic hypogonadotropic hypogonadism confirmed they are rare variants. Testing of the c.586-6 C-T mutation revealed no abnormal splicing. Surface plasmon resonance analysis of the p.L50F, p.S202C, and p.Q361P mutations showed no altered Gas6 ligand binding. In contrast, GT1-7 GnRH neuronal cells expressing p.S202C or p.Q361P demonstrated defective ligand dependent receptor processing and importantly aberrant neuronal migration. In addition, the p.Q361P showed defective ligand independent chemotaxis. Conclusions: Functional consequences of AXL sequence variants in patients with idiopathic hypogonadotropic hypogonadism support the importance of AXL and the Tyro3, Axl, Mer (TAM) family in reproductive development. Copyright © 2014 by the Endocrine Society.

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