The Veterans Affairs Medical Center

Memphis, TN, United States

The Veterans Affairs Medical Center

Memphis, TN, United States
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Raikwar N.S.,University of Iowa | Thomas C.P.,University of Iowa | Thomas C.P.,The Veterans Affairs Medical Center
Physiological Reports | Year: 2017

We previously identified a 5ʹ variant alternate transcript of Sgk1 (Sgk1_v3) encoding an NH2-terminal variant Sgk1 isoform, Sgk1_i3 that, like Sgk1, is expressed in the distal convoluted tubule, connecting tubule and collecting duct and can stimulate epithelial Na+ transport (Am J Physiol Renal Physiol 303: F1527–F1533, 2012). We now demonstrate that, similar to Sgk1, aldosterone and glucocorticoids stimulate Sgk1_v3 expression in cell lines from the collecting duct and airway epithelia. In mice, short term aldosterone infusion and maneuvers that increase endogenous aldosterone secretion including dietary Na+ deprivation and K+ loading increases distal nephron Sgk1_v3 expression in vivo. Although Sgk1_v3 has a different 5ʹ proximal regulatory region from Sgk1, the transcription start sites are less than 1000 bp apart. We cloned the 5ʹ regulatory region for Sgk1 and Sgk_v3 upstream of a luciferase gene and by deletion and reporter gene analysis we localized the corticosteroid regulatory region for Sgk1_v3 to a glucocorticoid response element (GRE) that had previously been identified for Sgk1 (Am J Physiol Endo Metab 283: E971–E979, 2002). We tested this element with MR in an MR-null cell line and demonstrate that aldosterone stimulates Sgk1 and Sgk1_v3 via this GRE. We conclude that corticosteroids stimulate Sgk1 and Sgk1_v3 expression in epithelial cells via activation of a common conserved GRE in the 5ʹ flanking region of Sgk1. © Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

PubMed | University of Pennsylvania, University of Vermont, University of California at Los Angeles, University of Oregon and 3 more.
Type: Journal Article | Journal: Journal of cutaneous pathology | Year: 2016

To understand the sophisticated nature of coming to consensus when diagnosing complex melanocytic lesions among a panel of experienced dermatopathologists.A total of 240 melanocytic lesions were assessed independently by three experienced dermatopathologists with their diagnoses mapped into one of five Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-DX) categories: (I) nevus/mild atypia, (II) moderate atypia, (III) severe atypia/melanoma in situ, (IV) T1a invasive melanoma and (V) T1b invasive melanoma. The dermatopathologists then discussed the cases, using a modified Delphi method to facilitated consensus building for cases with discordant diagnoses.For most cases, a majority of interpretations (two or three of three) agreed with the consensus diagnosis in 95% of Category I, 64% of Category II, 84% of Category III, 88% for Category IV and 100% of Category V cases. Disagreements were typically due to diagnostic threshold differences (64.5%), differing contents on slides even though the slides were sequential cuts (18.5%), and missed findings (15.3%). Disagreements were resolved via discussion of histopathologic features and their significance while reviewing the slides using a multi-headed microscope, considering treatment recommendations, citing existing literature, reviewing additional slides for a case, and choosing a provisional/borderline diagnosis to capture diverse opinions. All experienced pathologists participating in this study reported that the process of coming to consensus was challenging for borderline cases and may have represented compromise rather than consensus. They also reported the process changed their approaches to diagnosing complex melanocytic lesions.The most frequent reason for disagreement of experienced dermatopathologists was differences in diagnostic thresholds related to observer viewpoints. A range of approaches was needed to come to consensus, and this may guide pathology groups who do not currently hold consensus conferences.

Preisler N.,Copenhagen University | Haller R.G.,University of Texas Southwestern Medical Center | Haller R.G.,The Veterans Affairs Medical Center | Haller R.G.,Institute for Exercise and Environmental Medicine of Presbyterian Hospital | Vissing J.,Copenhagen University
Journal of Inherited Metabolic Disease | Year: 2015

Glycogen storage diseases (GSD) are inborn errors of glycogen or glucose metabolism. In the GSDs that affect muscle, the consequence of a block in skeletal muscle glycogen breakdown or glucose use, is an impairment of muscular performance and exercise intolerance, owing to 1) an increase in glycogen storage that disrupts contractile function and/or 2) a reduced substrate turnover below the block, which inhibits skeletal muscle ATP production. Immobility is associated with metabolic alterations in muscle leading to an increased dependence on glycogen use and a reduced capacity for fatty acid oxidation. Such changes may be detrimental for persons with GSD from a metabolic perspective. However, exercise may alter skeletal muscle substrate metabolism in ways that are beneficial for patients with GSD, such as improving exercise tolerance and increasing fatty acid oxidation. In addition, a regular exercise program has the potential to improve general health and fitness and improve quality of life, if executed properly. In this review, we describe skeletal muscle substrate use during exercise in GSDs, and how blocks in metabolic pathways affect exercise tolerance in GSDs. We review the studies that have examined the effect of regular exercise training in different types of GSD. Finally, we consider how oral substrate supplementation can improve exercise tolerance and we discuss the precautions that apply to persons with GSD that engage in exercise. © 2014, SSIEM.

Parker B.D.,University of California at San Diego | Parker B.D.,The Veterans Affairs San Diego Healthcare System | Schurgers L.J.,Maastricht University | Vermeer C.,Maastricht University | And 6 more authors.
Atherosclerosis | Year: 2010

Objective: Mitral annular calcification (MAC) and aortic stenosis (AS) are associated with systemic calcification and cardiovascular disease (CVD) events. Matrix Gla protein (MGP) is an inhibitor of vascular calcification and lower levels of its precursor - uncarboxylated MGP (ucMGP) - are associated with vascular calcification in pilot studies. Methods and results: In this cross-sectional study of 839 outpatients with stable CVD, we measured serum ucMGP, and evaluated MAC and AS by echocardiography. The association of ucMGP with MAC differed by diabetes status (interaction P<0.001). Among participants without diabetes (n=615), higher ucMGP (per standard deviation [1178. nM] increase) was associated with lower odds of MAC (odds ratio [OR] 0.73; 95% confidence interval [CI] 0.55-0.97) in models adjusted for traditional CVD risk factors, C-reactive protein, and kidney function. Among persons with diabetes (n=221), higher ucMGP was associated with higher odds of MAC (OR 1.89; 95% CI 1.29-2.78). Results were qualitatively similar for the association of ucMGP with AS although not statistically significant. Conclusions: Among outpatients with stable CVD, higher ucMGP is associated with lower odds of MAC in persons without diabetes, and higher odds of MAC in persons with diabetes. Future studies should determine whether ucMGP levels are associated with CVD events, and whether such associations differ by diabetes status. © 2009.

Vissing J.,Copenhagen University | Haller R.G.,University of Texas Southwestern Medical Center | Haller R.G.,The Veterans Affairs Medical Center | Haller R.G.,Institute for Exercise and Environmental Medicine of Presbyterian Hospital
Neuromuscular Disorders | Year: 2012

Exertional fatigue early in exercise is a clinical hallmark of muscle glycogenoses, which is often coupled with painful muscle contractures and episodes of myoglobinuria. A fundamental biochemical problem in these conditions is the impaired generation of ATP to fuel muscle contractions, which relates directly to the metabolic defect, but also to substrate-limited energy deficiency, as exemplified by the " second wind" phenomenon in McArdle disease. A number of secondary events may also play a role in inducing premature fatigue in glycogenoses, including (1) absent or blunted muscle acidosis, which may be important for maintaining muscle membrane excitability by decreasing chloride permeability, (2) loss of the osmotic effect related to lactate accumulation, which may account for absence of the normal increase in water content of exercised muscle, and thus promote higher than normal concentrations of extracellular potassium in exercising muscle and (3) exaggerated accumulation of ADP during exercise that may inhibit sodium-potassium and calcium-ATPases. Disorders of muscle glycogenolysis and glycolysis reveal the crucial role of these metabolic processes for supplying both anaerobic and aerobic energy for muscle contraction; and the pathological fatigue that occurs when glycogenolysis and/or glycolysis is blocked imply an important role for theses metabolic pathways in normal muscle fatigue. © 2012 Elsevier B.V.

Ulland T.K.,University of Iowa | Janowski A.M.,University of Iowa | Buchan B.W.,University of Iowa | Faron M.,University of Iowa | And 4 more authors.
Infection and Immunity | Year: 2013

Francisella tularensis is a Gram-negative bacterium and the causative agent of the diseasetularemia. Escape of F. tularensis from the phagosome into the cytosol of the macrophage triggers the activation of the AIM2 inflammasome through a mechanism that is not well understood. Activation of the AIM2 inflammasome results in autocatalytic cleavage of caspase-1, resulting in the processing and secretion of interleukin-1β (IL-1β) and IL-18, which play a crucial role in innate immune responses to F. tularensis. We have identified the 5-formyltetrahydrofolate cycloligase gene (FTL_0724) as being important for F. tularensis live vaccine strain (LVS) virulence. Infection of mice in vivo with a F. tularensis LVS FTL_0724 mutant resulted in diminished mortality compared to infection of mice with wild-type LVS. The FTL_0724 mutant also induced increased inflammasome-dependent IL-1β and IL-18 secretion and cytotoxicity in macrophages in vitro. In contrast, infection of macrophages with a F. tularensis LVS rluD pseudouridine synthase (FTL_0699) mutant resulted in diminished IL-1β and IL-18 secretion from macrophages in vitro compared to infection of macrophages with wild-type LVS. In addition, the FTL_0699 mutant was not attenuated in vivo. These findings further illustrate that F. tularensis LVS possesses numerous genes that influence its ability to activate the inflammasome, which is a key host strategy to control infection with this pathogen in vivo. © 2013, American Society for Microbiology.

Palacio A.M.,University of Miami | Palacio A.M.,The Veterans Affairs Medical Center | Kirolos I.,The Veterans Affairs Medical Center | Kirolos I.,University of Miami | And 2 more authors.
Patient Preference and Adherence | Year: 2015

Background: New oral anticoagulants have similar efficacy and lower bleeding rates compared with warfarin. However, in case of bleeding there is no specific antidote to reverse their effects. We evaluated the preferences and values of anticoagulants of patients at risk of atrial fibrillation and those who have already made a decision regarding anticoagulation. Methods: We conducted a cross-sectional study of Veterans in the primary care clinics and the international normalized ratio (INR) laboratory. We developed an instrument with patient and physician input to measure patient values and preferences. The survey contained a hypothetical scenario of the risk of atrial fibrillation and the attributes of each anticoagulant. After the scenario, we asked participants to choose the option that best fits their preferences. The options were: 1) has better efficacy at reducing risk of stroke; 2) has been in the market for a long period of time; 3) has an antidote to reverse the rare case of bleeding; 4) has better quality of life profile with no required frequent laboratory tests; or 5) I want to follow physician recommendations. We stratified our results by those patients who are currently exposed to anticoagulants and those who are not exposed but are at risk of atrial fibrillation. Results: We approached 173 Veterans and completed 137 surveys (79% response rate). Ninety subjects were not exposed to anticoagulants, 46 reported being on warfarin, and one reported being on dabigatran at the time of the survey. Ninety-eight percent of subjects stated they would like to participate in the decision-making process of selecting an anticoagulant. Thirty-six percent of those exposed and 37% of those unexposed to anticoagulants reported that they would select a medication that has an antidote even if the risk of bleeding was very small. Twenty-three percent of the unexposed and 22% of the exposed groups reported that they would prefer the medication that gives the best quality of life. Conclusion: Our study found that patients who may be exposed to an anticoagulation decision prefer to actively participate in the decision-making process, and have individual values for making a decision that cannot be predicted or assumed by anyone in the health care system. © 2015 Palacio et al.

Penfound T.A.,University of Tennessee Health Science Center | Penfound T.A.,The Veterans Affairs Medical Center | Chiang E.Y.,University of Tennessee Health Science Center | Chiang E.Y.,The Veterans Affairs Medical Center | And 4 more authors.
Vaccine | Year: 2010

The amino terminal region of group A streptococcal M proteins evokes type-specific immunity while the conserved C-repeat epitopes evoke cross-protective immunity against multiple serotypes. The present studies were undertaken to compare the protective efficacy of vaccines containing either type-specific (hexavalent vaccine) or conserved C-repeat (J14 vaccine) M protein epitopes and to determine if combination vaccines resulted in enhanced levels of protection. Our results indicated that the protective efficacy of the type-specific vaccine was significantly greater than that of J14 and that the addition of J14 to vaccine formulations did not enhance the level of protection achieved with type-specific formulations. © 2010.

Porollo A.,Cincinnati Childrens Hospital Medical Center | Sesterhenn T.M.,The Veterans Affairs Medical Center | Sesterhenn T.M.,University of Cincinnati | Collins M.S.,The Veterans Affairs Medical Center | And 4 more authors.
mBio | Year: 2014

In the context of deciphering the metabolic strategies of the obligate pathogenic fungi in the genus Pneumocystis, the genomes of three species (P. carinii, P. murina, and P. jirovecii) were compared among themselves and with the free-living, phylogenetically related fission yeast (Schizosaccharomyces pombe). The underrepresentation of amino acid metabolism pathways compared to those in S. pombe, as well as the incomplete steroid biosynthesis pathway, were confirmed for P. carinii and P. jirovecii and extended to P. murina. All three Pneumocystis species showed overrepresentation of the inositol phosphate metabolism pathway compared to that in the fission yeast. In addition to those known in S. pombe, four genes, encoding inositolpolyphosphate multikinase (EC, inositol-pentakisphosphate 2-kinase (EC, phosphoinositide 5-phosphatase (EC, and inositol-1,4-bisphosphate 1-phosphatase (EC, were identified in the two rodent Pneumocystis genomes, P. carinii and P. murina. The P. jirovecii genome appeared to contain three of these genes but lacked phosphoinositide 5-phosphatase. Notably, two genes encoding enzymes essential for myo-inositol synthesis, inositol-1-phosphate synthase (INO1) and inositol monophosphatase (INM1), were absent from all three genomes, suggesting that Pneumocystis species are inositol auxotrophs. In keeping with the need to acquire exogenous inositol, two genes with products homologous to fungal inositol transporters, ITR1 and ITR2, were identified in P. carinii and P. murina, while P. jirovecii contained only the ITR1 homolog. The ITR and inositol metabolism genes in P. murina and P. carinii were expressed during fulminant infection as determined by reverse transcriptase real-time PCR of cDNA from infected lung tissue. Supplementation of in vitro culture with inositol yielded significant improvement of the viability of P. carinii for days 7 through 14.IMPORTANCE Microbes in the genus Pneumocystis are obligate pathogenic fungi that reside in mammalian lungs and cause Pneumocystis pneumonia in hosts with weakened immune systems. These fungal infections are not responsive to standard antifungal therapy. A long-term in vitro culture system is not available for these fungi, impeding the study of their biology and genetics and new drug development. Given that all genomes of the Pneumocystis species analyzed lack the genes for inositol synthesis and contain inositol transporters, Pneumocystis fungi, like S. pombe, appear to be inositol auxotrophs. Inositol is important for the pathogenesis, virulence, and mating processes in Candida albicans and Cryptococcus neoformans, suggesting similar importance within the Pneumocystis species as well. This is the first report to (i) characterize genes in the inositol phosphate metabolism and transport pathways in Pneumocystis species and (ii) identify inositol as a supplement that improved the viability of P. carinii in in vitro culture. © 2014 Porollo et al

Landazuri N.,Emory University | Joseph G.,Emory University | Guldberg R.E.,Georgia Institute of Technology | Robert Taylor W.,Emory University | And 2 more authors.
American Journal of Physiology - Regulatory Integrative and Comparative Physiology | Year: 2012

The formation of vascular networks during embryogenesis and early stages of development encompasses complex and tightly regulated growth of blood vessels, followed by maturation of some vessels, and spatially controlled disconnection and pruning of others. The adult vasculature, while more quiescent, is also capable of adapting to changing physiological conditions by remodeling blood vessels. Numerous studies have focused on understanding key factors that drive vessel growth in the adult in response to ischemic injury. However, little is known about the extent of vessel rarefaction and its potential contribution to the final outcome of vascular recovery. We addressed this topic by characterizing the endogenous phases of vascular repair in a mouse model of hindlimb ischemia. We showed that this process is biphasic. It encompasses an initial rapid phase of vessel growth, followed by a later phase of vessel rarefaction. In healthy mice, this process resulted in partial recovery of perfusion and completely restored the ability of mice to run voluntarily. Given that the ability to revascularize can be compromised by a cardiovascular risk factor such as diabetes, we also examined vascular repair in diabetic mice. We found that paradoxically both the initial growth and subsequent regression of collateral vessels were more pronounced in the setting of diabetes and resulted in impaired recovery of perfusion and impaired functional status. In conclusion, our findings demonstrate that the formation of functional collateral vessels in the hindlimb requires vessel growth and subsequent vessel rarefaction. In the setting of diabetes, the physiological defect was not in the initial formation of vessels but rather in the inability to sustain newly formed vessels. © 2012 the American Physiological Society.

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