1
|
Tarantini S, Giles CB, Wren JD, Ashpole NM, Valcarcel-Ares MN, Wei JY, Sonntag WE, Ungvari Z, Csiszar A. IGF-1 deficiency in a critical period early in life influences the vascular aging phenotype in mice by altering miRNA-mediated post-transcriptional gene regulation: implications for the developmental origins of health and disease hypothesis. AGE (DORDRECHT, NETHERLANDS) 2016; 38:239-258. [PMID: 27566308 PMCID: PMC5061677 DOI: 10.1007/s11357-016-9943-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 07/29/2016] [Indexed: 06/06/2023]
Abstract
Epidemiological findings support the concept of Developmental Origins of Health and Disease, suggesting that early-life hormonal influences during a sensitive period of development have a fundamental impact on vascular health later in life. The endocrine changes that occur during development are highly conserved across mammalian species and include dramatic increases in circulating IGF-1 levels during adolescence. The present study was designed to characterize the effect of developmental IGF-1 deficiency on the vascular aging phenotype. To achieve that goal, early-onset endocrine IGF-1 deficiency was induced in mice by knockdown of IGF-1 in the liver using Cre-lox technology (Igf1 f/f mice crossed with mice expressing albumin-driven Cre recombinase). This model exhibits low-circulating IGF-1 levels during the peripubertal phase of development, which is critical for the biology of aging. Due to the emergence of miRNAs as important regulators of the vascular aging phenotype, the effect of early-life IGF-1 deficiency on miRNA expression profile in the aorta was examined in animals at 27 months of age. We found that developmental IGF-1 deficiency elicits persisting late-life changes in miRNA expression in the vasculature, which significantly differed from those in mice with adult-onset IGF-1 deficiency (TBG-Cre-AAV8-mediated knockdown of IGF-1 at 5 month of age in Igf1 f/f mice). Using a novel computational approach, we identified miRNA target genes that are co-expressed with IGF-1 and associate with aging and vascular pathophysiology. We found that among the predicted targets, the expression of multiple extracellular matrix-related genes, including collagen-encoding genes, were downregulated in mice with developmental IGF-1 deficiency. Collectively, IGF-1 deficiency during a critical period during early in life results in persistent changes in post-transcriptional miRNA-mediated control of genes critical targets for vascular health, which likely contribute to the deleterious late-life cardiovascular effects known to occur with developmental IGF-1 deficiency.
Collapse
Affiliation(s)
- Stefano Tarantini
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Cory B Giles
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Oklahoma Medical Research Foundation, Arthritis & Clinical Immunology Research Program, Oklahoma City, OK, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Jonathan D Wren
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Oklahoma Medical Research Foundation, Arthritis & Clinical Immunology Research Program, Oklahoma City, OK, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Nicole M Ashpole
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - M Noa Valcarcel-Ares
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Jeanne Y Wei
- Reynolds Institute on Aging and Department of Geriatrics, University of Arkansas for Medical Science, 4301 West Markham Street, No. 748, Little Rock, AR, 72205, USA
| | - William E Sonntag
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Zoltan Ungvari
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Anna Csiszar
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
| |
Collapse
|
2
|
Barbosa EJL, Glad CAM, Nilsson AG, Bosaeus N, Nyström HF, Svensson PA, Bengtsson BÅ, Nilsson S, Bosaeus I, Boguszewski CL, Johannsson G. Extracellular water and blood pressure in adults with growth hormone (GH) deficiency: a genotype-phenotype association study. PLoS One 2014; 9:e105754. [PMID: 25157616 PMCID: PMC4144955 DOI: 10.1371/journal.pone.0105754] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 07/28/2014] [Indexed: 12/18/2022] Open
Abstract
Objectives Growth hormone deficiency (GHD) in adults is associated with decreased extracellular water volume (ECW). In response to GH replacement therapy (GHRT), ECW increases and blood pressure (BP) reduces or remains unchanged. Our primary aim was to study the association between polymorphisms in genes related to renal tubular function with ECW and BP before and 1 year after GHRT. The ECW measures using bioimpedance analysis (BIA) and bioimpedance spectroscopy (BIS) were validated against a reference method, the sodium bromide dilution method (Br−). Design and Methods Using a candidate gene approach, fifteen single-nucleotide polymorphisms (SNPs) in nine genes with known impact on renal tubular function (AGT, SCNN1A, SCNN1G, SLC12A1, SLC12A3, KCNJ1, STK39, WNK1 and CASR) were genotyped and analyzed for associations with ECW and BP at baseline and with their changes after 1 year of GHRT in 311 adult GHD patients. ECW was measured with the Br−, BIA, and BIS. Results Both BIA and BIS measurements demonstrated similar ECW results as the reference method. At baseline, after adjustment for sex and BMI, SNP rs2291340 in the SLC12A1 gene was associated with ECW volume in GHD patients (p = 0.039). None of the SNPs influenced the ECW response to GHRT. One SNP in the SLC12A3 gene (rs11643718; p = 0.024) and three SNPs in the SCNN1G gene [rs5723 (p = 0.02), rs5729 (p = 0.016) and rs13331086 (p = 0.035)] were associated with the inter-individual differences in BP levels at baseline. A polymorphism in the calcium-sensing receptor (CASR) gene (rs1965357) was associated with changes in systolic BP after GHRT (p = 0.036). None of these associations remained statistically significant when corrected for multiple testing. Conclusion The BIA and BIS are as accurate as Br− to measure ECW in GHD adults before and during GHRT. Our study provides the first evidence that individual polymorphisms may have clinically relevant effects on ECW and BP in GHD adults.
Collapse
Affiliation(s)
- Edna J. L. Barbosa
- Department of Endocrinology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- SEMPR, Servico de Endocrinologia e Metabologia do Hospital de Clínicas da Universidade Federal do Paraná, Curitiba, Brazil
| | - Camilla A. M. Glad
- Department of Endocrinology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anna G. Nilsson
- Department of Endocrinology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Bosaeus
- Department of Clinical Nutrition Unit, Sahlgrenska University Hospital, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Helena Filipsson Nyström
- Department of Endocrinology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Per-Arne Svensson
- Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Bengt-Åke Bengtsson
- Department of Endocrinology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Staffan Nilsson
- Institute of Mathematical Sciences, Department of Mathematical Statistics, Chalmers University of Technology, Chalmers, Gothenburg, Sweden
| | - Ingvar Bosaeus
- Department of Clinical Nutrition Unit, Sahlgrenska University Hospital, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Cesar Luiz Boguszewski
- SEMPR, Servico de Endocrinologia e Metabologia do Hospital de Clínicas da Universidade Federal do Paraná, Curitiba, Brazil
| | - Gudmundur Johannsson
- Department of Endocrinology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
| |
Collapse
|
3
|
Reddy AK, Hartley CJ, Pham TT, Darlington G, Entman ML, Taffet GE. Young little mice express a premature cardiovascular aging phenotype. J Gerontol A Biol Sci Med Sci 2013; 69:152-9. [PMID: 23682160 DOI: 10.1093/gerona/glt055] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To investigate the effect of growth hormone and insulin-like growth factor 1 deficiency on the aging mouse arterial system, we compared the hemodynamics in young (4 months) and old (30 months) growth hormone-releasing hormone receptor null dwarf (Little) mice and their wild-type littermates. Young Little mice had significantly lower peak and mean aortic velocity and significantly higher aortic impedance than young wild-type mice. However, unlike the wild-type mice, there were no significant changes in arterial function with age in the Little mice. Aortic pulse wave velocity estimated using characteristic impedance increased with age in the wild-type mice, but it changed minimally in the Little mouse. We therefore conclude that arterial function in Little mice expresses a premature aging phenotype at young age and may neither enhance nor reduce their longevity.
Collapse
Affiliation(s)
- Anilkumar K Reddy
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, MS BCM620, Houston, TX 77030.
| | | | | | | | | | | |
Collapse
|
4
|
Gray C, Li M, Reynolds CM, Vickers MH. Pre-weaning growth hormone treatment reverses hypertension and endothelial dysfunction in adult male offspring of mothers undernourished during pregnancy. PLoS One 2013; 8:e53505. [PMID: 23308239 PMCID: PMC3538633 DOI: 10.1371/journal.pone.0053505] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/30/2012] [Indexed: 12/03/2022] Open
Abstract
Maternal undernutrition results in elevated blood pressure (BP) and endothelial dysfunction in adult offspring. However, few studies have investigated interventions during early life to ameliorate the programming of hypertension and vascular disorders. We have utilised a model of maternal undernutrition to examine the effects of pre-weaning growth hormone (GH) treatment on BP and vascular function in adulthood. Female Sprague-Dawley rats were fed either a standard control diet (CON) or 50% of CON intake throughout pregnancy (UN). From neonatal day 3 until weaning (day 21), CON and UN pups received either saline (CON-S, UN-S) or GH (2.5 ug/g/day)(CON-GH, UN-GH). All dams were fed ad libitum throughout lactation. Male offspring were fed a standard diet until the end of the study. Systolic blood pressure (SBP) was measured at day 150 by tail cuff plethysmography. At day 160, intact mesenteric vessels mounted on a pressure myograph. Responses to pressure, agonist-induced constriction and endothelium-dependent vasodilators were investigated to determine vascular function. SBP was increased in UN-S groups and normalised in UN-GH groups (CON-S 121±2 mmHg, CON-GH 115±3, UN-S 146±3, UN-GH 127±2). Pressure mediated dilation was reduced in UN-S offspring and normalised in UN-GH groups. Vessels from UN-S offspring demonstrated a reduced constrictor response to phenylephrine and reduced vasodilator response to acetylcholine (ACh). Furthermore, UN-S offspring vessels displayed a reduced vasodilator response in the presence of L-NG-Nitroarginine Methyl Ester (L-NAME), carbenoxolone (CBX), L-NAME and CBX, Tram-34 and Apamin. UN-GH vessels showed little difference in responses when compared to CON and significantly increased vasodilator responses when compared to UN-S offspring. Pre-weaning GH treatment reverses the negative effects of maternal UN on SBP and vasomotor function in adult offspring. These data suggest that developmental cardiovascular programming is potentially reversible by early life GH treatment and that GH can reverse the vascular adaptations resulting from maternal undernutrition.
Collapse
Affiliation(s)
- Clint Gray
- Liggins Institute and Gravida, National Centre for Growth and Development, University of Auckland, Auckland, New Zealand.
| | | | | | | |
Collapse
|
5
|
Ungvari Z, Csiszar A. The emerging role of IGF-1 deficiency in cardiovascular aging: recent advances. J Gerontol A Biol Sci Med Sci 2012; 67:599-610. [PMID: 22451468 DOI: 10.1093/gerona/gls072] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This review focuses on cardiovascular protective effects of insulin-like growth factor (IGF)-1, provides a landscape of molecular mechanisms involved in cardiovascular alterations in patients and animal models with congenital and adult-onset IGF-1 deficiency, and explores the link between age-related IGF-1 deficiency and the molecular, cellular, and functional changes that occur in the cardiovascular system during aging. Microvascular protection conferred by endocrine and paracrine IGF-1 signaling, its implications for the pathophysiology of cardiac failure and vascular cognitive impairment, and the role of impaired cellular stress resistance in cardiovascular aging considered here are based on emerging knowledge of the effects of IGF-1 on Nrf2-driven antioxidant response.
Collapse
Affiliation(s)
- Zoltan Ungvari
- Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1303, Oklahoma City, OK 73104, USA.
| | | |
Collapse
|
6
|
Groban L, Lin M, Kassik KA, Ingram RL, Sonntag WE. Early-onset growth hormone deficiency results in diastolic dysfunction in adult-life and is prevented by growth hormone supplementation. Growth Horm IGF Res 2011; 21:81-88. [PMID: 21371927 PMCID: PMC3085723 DOI: 10.1016/j.ghir.2011.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 01/27/2011] [Accepted: 01/29/2011] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The primary goal of growth hormone (GH) replacement is to promote linear growth in children with growth hormone deficiency (GHD). GH and insulin-like growth factor-1 (IGF-1) are also known to have roles in cardiac development and as modulators of myocardial structure and function in the adult heart. However, little is known about cardiac diastolic function in young adults with childhood onset GH deficiency in which GH treatment was discontinued following puberty. The aim of the study was to evaluate the effects of long standing GHD and peri-pubertal or continuous GH replacement therapy on diastolic function in the adult dwarf rat. DESIGN The dwarf rat, which possesses a mutation in a transcription factor necessary for development of the somatotroph, does not exhibit the normal peri-pubertal rise in GH around day 28 and was used to model childhood or early-onset GHD (EOGHD). In another group of male dwarfs, GH replacement therapy was initiated at 4 weeks of age when GH pulsatility normally begins. Ten weeks after initiation of injections, GH-treated dwarf rats were divided into 2 groups; continued treatment with GH for 12 weeks (GH-replete) or treatment with saline for 12 weeks. This latter group models GH supplementation during adolescence with GHD beginning in adulthood (adult-onset GHD; AOGHD). Saline-treated heterozygous (HZ) rats were used as age-matched controls. At 26 weeks of age, cardiac function was assessed using invasive or noninvasive (conventional and tissue Doppler) indices of myocardial contractility and lusitropy. RESULTS Systolic function, as determined by echocardiography, was similar among groups. Compared with HZ rats and GH-replete dwarfs, the EOGHD group exhibited significant reductions in myocardial relaxation and increases in left ventricular filling pressure, indicative of moderate diastolic dysfunction. This was further associated with a decrease in the cardiac content of sarcoplasmic reticulum Ca(2+) ATPase (SERCA2), one of the important cardiac calcium regulatory proteins. Dwarfs supplemented with GH during the peri-adolescence stage, but not beyond (AOGHD), exhibited a subtle prolongation in the deceleration time to early filling. In contrast, continual GH replacement preserved diastolic function such that the cardiac phenotype of the GH-replete dwarfs resembled that of their age-matched HZ counterpart. DISCUSSION Our data indicate that GHD during adolescence leads to overt diastolic dysfunction in early adulthood and this is prevented by continual GH replacement therapy. Since discontinuation of GH replacement following adolescence only mitigated the lusitropic deficits that were observed in untreated dwarfs, GH treatment into adulthood could be beneficial.
Collapse
Affiliation(s)
- L Groban
- Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1009, USA.
| | | | | | | | | |
Collapse
|
7
|
Groban L, Jobe H, Lin M, Houle T, Kitzman DA, Sonntag W. Effects of short-term treadmill exercise training or growth hormone supplementation on diastolic function and exercise tolerance in old rats. J Gerontol A Biol Sci Med Sci 2008; 63:911-20. [PMID: 18840795 DOI: 10.1093/gerona/63.9.911] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Whether the lusitropic potential of short-term exercise in aged rats is linked to an augmentation in the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and an alteration in the cardiac renin angiotensin system (RAS) is unknown. Old (28-month-old) male, Fischer 344xBrown Norway rats were randomized to 4 weeks of GH supplementation (300 microg subcutaneous, twice daily) or 4 weeks of treadmill running, or were used as sedentary controls. Six-month-old rats, sedentary or exercised, were used as young controls. Training improved exercise capacity in old animals. Exercise and GH attenuated age-related declines in myocardial relaxation despite an exercise-induced suppression of IGF-1. The regulatory protein, sarcoplasmic Ca2+ adenosine triphosphatase (SERCA2), increased with exercise but not GH. Among aged rats, the cardiac RAS was not altered by training or GH. Thus, the signaling pathway underlying the lusitropic benefit of short-term habitual exercise in the aged rat may be distinct from GH-mediated benefits and independent of the cardiac RAS.
Collapse
Affiliation(s)
- Leanne Groban
- Department of Anesthesiology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1009, USA.
| | | | | | | | | | | |
Collapse
|
8
|
Tivesten A, Isgaard J. Cardiovascular and Respiratory Systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2005; 567:149-66. [PMID: 16370139 DOI: 10.1007/0-387-26274-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Asa Tivesten
- Research Center for Endocrinology and Metabolism, Department of Internal Medicine, Sahlgrenska Academy at the University of Göteborg, Sweden
| | | |
Collapse
|
9
|
Ren J, Brown-Borg HM. Impaired cardiac excitation-contraction coupling in ventricular myocytes from Ames dwarf mice with IGF-I deficiency. Growth Horm IGF Res 2002; 12:99-105. [PMID: 12175647 DOI: 10.1054/ghir.2002.0267] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are involved in the regulation of cardiovascular function. GH/IGF-I deficiency is associated with impaired cardiac performance manifested as reduced left ventricular ejection fraction and diastolic filling. This study was to determine the impact of IGF-I deficiency on single cardiac myocyte excitation-contraction (E-C) coupling. Ventricular myocytes were isolated from adult Ames dwarf mice and age-matched wild-type siblings. Dwarf mice are characterized by severe IGF-I deficiency. Mechanical properties were evaluated using a video edge detection system. Myocytes were electrically stimulated at 0.5 Hz. The contractile properties analysed included peak shortening (PS), time to peak shortening (TPS) and time to 90% relengthening (TR(90)), and maximal velocities of shortening/relengthening (+/-d L/d t). Intracellular Ca(2+) transients were evaluated by fura-2 fluorescence microscopy. Dwarf mice exhibited significantly reduced body and heart weights and severely deficient plasma IGF-I. Myocytes from dwarf mice displayed significantly smaller cell lengths (CLs), prolonged TPS/TR(90) and reduced +/-d L/d t compared with the wild-type littermates. The absolute PS was similar although PS/CL was enhanced in the dwarf group. Myocytes from dwarf animals displayed reduced peak intracellular Ca(2+) levels and slowed intracellular Ca(2+) clearing associated with a comparable resting intracellular Ca(2+). Furthermore, myocytes from the dwarf hearts were equally responsive to an elevation in extracellular Ca(2+) and exhibited an augmented stepwise decrease in response to minimal increase in stimulating frequencies compared with those from the wild-type group. These results suggest that deficiency in IGF-I may be directly associated with cardiac E-C coupling dysfunction at the ventricular myocyte level.
Collapse
Affiliation(s)
- Jun Ren
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine, Grand Forks 58203, USA.
| | | |
Collapse
|