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Allison BJ, Brain KL, Niu Y, Kane AD, Herrera EA, Thakor AS, Botting KJ, Cross CM, Itani N, Shaw CJ, Skeffington KL, Beck C, Giussani DA. Altered Cardiovascular Defense to Hypotensive Stress in the Chronically Hypoxic Fetus. Hypertension 2020; 76:1195-1207. [PMID: 32862711 PMCID: PMC7480941 DOI: 10.1161/hypertensionaha.120.15384] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Supplemental Digital Content is available in the text. The hypoxic fetus is at greater risk of cardiovascular demise during a challenge, but the reasons behind this are unknown. Clinically, progress has been hampered by the inability to study the human fetus non-invasively for long period of gestation. Using experimental animals, there has also been an inability to induce gestational hypoxia while recording fetal cardiovascular function as the hypoxic pregnancy is occurring. We use novel technology in sheep pregnancy that combines induction of controlled chronic hypoxia with simultaneous, wireless recording of blood pressure and blood flow signals from the fetus. Here, we investigated the cardiovascular defense of the hypoxic fetus to superimposed acute hypotension. Pregnant ewes carrying singleton fetuses surgically prepared with catheters and flow probes were randomly exposed to normoxia or chronic hypoxia from 121±1 days of gestation (term ≈145 days). After 10 days of exposure, fetuses were subjected to acute hypotension via fetal nitroprusside intravenous infusion. Underlying in vivo mechanisms were explored by (1) analyzing fetal cardiac and peripheral vasomotor baroreflex function; (2) measuring the fetal plasma catecholamines; and (3) establishing fetal femoral vasoconstrictor responses to the α1-adrenergic agonist phenylephrine. Relative to controls, chronically hypoxic fetal sheep had reversed cardiac and impaired vasomotor baroreflex function, despite similar noradrenaline and greater adrenaline increments in plasma during hypotension. Chronic hypoxia markedly diminished the fetal vasopressor responses to phenylephrine. Therefore, we show that the chronically hypoxic fetus displays markedly different cardiovascular responses to acute hypotension, providing in vivo evidence of mechanisms linking its greater susceptibility to superimposed stress.
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Affiliation(s)
- Beth J Allison
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Kirsty L Brain
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Youguo Niu
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Andrew D Kane
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | | | - Avnesh S Thakor
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Kimberley J Botting
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Christine M Cross
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Nozomi Itani
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Caroline J Shaw
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.).,Institute of Reproductive and Developmental Biology, Imperial College, London United Kingdom (C.J.S.)
| | - Katie L Skeffington
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Chritian Beck
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Dino A Giussani
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.).,Cambridge Cardiovascular Strategic Research Initiative (D.A.G.).,Cambridge Strategic Research Initiative in Reproduction (D.A.G.)
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Neonatal glucocorticoid overexposure alters cardiovascular function in young adult horses in a sex-linked manner. J Dev Orig Health Dis 2020; 12:309-318. [PMID: 32489168 DOI: 10.1017/s2040174420000446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Prenatal glucocorticoid overexposure has been shown to programme adult cardiovascular function in a range of species, but much less is known about the long-term effects of neonatal glucocorticoid overexposure. In horses, prenatal maturation of the hypothalamus-pituitary-adrenal axis and the normal prepartum surge in fetal cortisol occur late in gestation compared to other precocious species. Cortisol levels continue to rise in the hours after birth of full-term foals and increase further in the subsequent days in premature, dysmature and maladapted foals. Thus, this study examined the adult cardiovascular consequences of neonatal cortisol overexposure induced by adrenocorticotropic hormone administration to full-term male and female pony foals. After catheterisation at 2-3 years of age, basal arterial blood pressures (BP) and heart rate were measured together with the responses to phenylephrine (PE) and sodium nitroprusside (SNP). These data were used to assess cardiac baroreflex sensitivity. Neonatal cortisol overexposure reduced both the pressor and bradycardic responses to PE in the young adult males, but not females. It also enhanced the initial hypotensive response to SNP, slowed recovery of BP after infusion and reduced the gain of the cardiac baroreflex in the females, but not males. Basal diastolic pressure and cardiac baroreflex sensitivity also differed with sex, irrespective of neonatal treatment. The results show that there is a window of susceptibility for glucocorticoid programming during the immediate neonatal period that alters cardiovascular function in young adult horses in a sex-linked manner.
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Fowden AL, Giussani DA, Forhead AJ. Physiological development of the equine fetus during late gestation. Equine Vet J 2020; 52:165-173. [PMID: 31721295 DOI: 10.1111/evj.13206] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/08/2019] [Indexed: 02/02/2023]
Abstract
In many species, the pattern of growth and physiological development in utero has an important role in determining not only neonatal viability but also adult phenotype and disease susceptibility. Changes in fetal development induced by a range of environmental factors including maternal nutrition, disease, placental insufficiency and social stresses have all been shown to induce adult cardiovascular and metabolic dysfunction that often lead to ill health in later life. Compared to other precocious animals, much less is known about the physiological development of the fetal horse or the longer-term impacts on its phenotype of altered development in early life because of its inaccessibility in utero, large size and long lifespan. This review summaries the available data on the normal metabolic, cardiovascular and endocrine development of the fetal horse during the second half of gestation. It also examines the responsiveness of these physiological systems to stresses such as hypoglycaemia and hypotension during late gestation. Particular emphasis is placed on the role of the equine placenta and fetal endocrine glands in mediating the changes in fetal development seen towards term and in response to nutritional and other environmental cues. The final part of the review presents the evidence that the early life environment of the horse can alter its subsequent metabolic, cardiovascular and endocrine phenotype as well as its postnatal growth and bone development. It also highlights the immediate neonatal environment as a key window of susceptibility for programming of equine phenotype. Although further studies are needed to identify the cellular and molecular mechanisms involved, developmental programming of physiological phenotype is likely to have important implications for the health and potential athletic performance of horses, particularly if born with abnormal bodyweight, premature or dysmature characteristics or produced by assisted reproductive technologies, indicative of an altered early life environment.
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Affiliation(s)
- A L Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - D A Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - A J Forhead
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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Jellyman JK, Fletcher AJW, Fowden AL, Giussani DA. Glucocorticoid Maturation of Fetal Cardiovascular Function. Trends Mol Med 2020; 26:170-184. [PMID: 31718939 DOI: 10.1016/j.molmed.2019.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 12/27/2022]
Abstract
The last decade has seen rapid advances in the understanding of the central role of glucocorticoids in preparing the fetus for life after birth. However, relative to other organ systems, maturation by glucocorticoids of the fetal cardiovascular system has been ignored. Here, we review the effects of glucocorticoids on fetal basal cardiovascular function and on the fetal cardiovascular defense responses to acute stress. This is important because glucocorticoid-driven maturational changes in fetal cardiovascular function under basal and stressful conditions are central to the successful transition from intra- to extrauterine life. The cost-benefit balance for the cardiovascular health of the preterm baby of antenatal glucocorticoid therapy administered to pregnant women threatened with preterm birth is also discussed.
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Affiliation(s)
- Juanita K Jellyman
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, USA.
| | | | - Abigail L Fowden
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK; Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK; Cambridge Strategic Research Initiative in Reproduction, Cambridge, UK
| | - Dino A Giussani
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK; Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK; Cambridge Strategic Research Initiative in Reproduction, Cambridge, UK.
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Isolating the direct effects of adverse developmental conditions on in vivo cardiovascular function at adulthood: the avian model. J Dev Orig Health Dis 2018; 9:460-466. [PMID: 29692274 PMCID: PMC6075699 DOI: 10.1017/s2040174418000247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
It is now well accepted that exposure to adverse environmental conditions in utero can predispose a fetus to disease later in life. Using an avian model to study the programming of disease has a unique advantage as it allows isolation of the direct effects of adverse conditions on fetal physiology, without any confounding effects via the mother or placenta. However, experiments in avian models are limited by the lack of well-established surgical protocols for the adult bird, which we have established in this study. Surgery was performed on seven young adult Bovan Brown chickens (body weight 1617±214 g, mean±s.d.) in order to instrument them with femoral arterial and venous catheters and a femoral arterial flow probe. Isoflurane and lidocaine were both found to have depressive effects on chicken cardiovascular function. Optimised methods of anaesthesia, intraoperative monitoring, surgical approach, postoperative care, and experimentation are described. Chickens recovered rapidly from surgery without significant blood gas perturbation, and basal in vivo cardiovascular studies were performed following 5 days of recovery. These techniques allow detailed investigation of avian cardiometabolic function, permitting determination of the consequences in later life of direct environmental insults to fetal physiology, isolated from additional effects on maternal physiology and/or placental endocrinology.
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Dembek KA, Hurcombe SD, Stewart AJ, Barr BS, MacGillivray KC, Kinee M, Elam J, Toribio RE. Association of aldosterone and arginine vasopressin concentrations and clinical markers of hypoperfusion in neonatal foals. Equine Vet J 2015; 48:176-81. [PMID: 25421257 DOI: 10.1111/evj.12393] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 11/19/2014] [Indexed: 11/30/2022]
Abstract
REASONS FOR PERFORMING STUDY Critically ill foals often present to veterinary hospitals with impaired organ perfusion which can be demonstrated by increased blood L-lactate concentrations. As a compensatory mechanism to low blood pressure and electrolyte abnormalities, aldosterone and arginine vasopressin (AVP) are released to restore organ perfusion and function. Several studies have investigated the ability of blood L-lactate concentrations to predict severity of disease and outcome in critically ill human patients, adult horses and foals. However, information on the aldosterone and AVP response to hypoperfusion and its association with L-lactate concentrations in neonatal foals is limited. OBJECTIVES To determine the association between clinical hypoperfusion and endocrine markers of reduced tissue perfusion in normo- and hypoperfused foals. STUDY DESIGN Prospective, multicentre, cross-sectional observational study. METHODS Blood samples were collected on admission from 72 clinically hypoperfused, 110 normoperfused (73 hospitalised and 37 healthy) foals of ≤4 days of age. Foals were considered clinically hypoperfused if they had L-lactate concentrations ≥2.5 mmol/l and one of the 3 following findings: heart rate >120 beats/min, packed cell volume (PCV) >0.44 l/l or azotaemia (increased creatinine and blood urea nitrogen [BUN]). Blood concentrations of aldosterone and AVP were determined by radioimmunoassays. RESULTS Aldosterone, AVP, creatinine and BUN concentrations and heart rate, PCV and blood osmolality were higher in clinically hypoperfused compared with normoperfused foals (P<0.05). Risk of hypoperfusion increased with the presence of hypothermic extremities (OR = 5.26) and with each one unit increase in albumin concentrations (OR = 3.5) (P<0.05). The proposed admission L-lactate cut-off value above which nonsurvival could be reliably predicted in hospitalised foals was 10.6 mmol/l with 82% of sensitivity and 74% of specificity. CONCLUSIONS Hyperaldosteronaemia and hypervasopressinaemia as well as hypothermic extremities and increased albumin concentrations are potent predictors of hypoperfusion in hospitalised foals.
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Affiliation(s)
- K A Dembek
- College of Veterinary Medicine, The Ohio State University, Columbus, USA
| | - S D Hurcombe
- College of Veterinary Medicine, The Ohio State University, Columbus, USA
| | - A J Stewart
- College of Veterinary Medicine, Auburn University, Alabama, USA
| | - B S Barr
- Rood and Riddle Equine Hospital, Lexington, Kentucky, USA
| | | | - M Kinee
- Rood and Riddle Equine Hospital, Lexington, Kentucky, USA
| | - J Elam
- Hagyard Equine Medical Institute, Lexington, Kentucky, USA
| | - R E Toribio
- College of Veterinary Medicine, The Ohio State University, Columbus, USA
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Borchers A, Magdesian KG, Schenck PA, Kass PH. Serial plasma vasopressin concentration in healthy and hospitalised neonatal foals. Equine Vet J 2013; 46:306-10. [DOI: 10.1111/evj.12121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 06/09/2013] [Indexed: 01/05/2023]
Affiliation(s)
- A. Borchers
- William R. Pritchard Veterinary Medical Teaching Hospital; University of California; USA
| | - K. G. Magdesian
- Department of Medicine and Epidemiology; University of California; USA
| | - P. A. Schenck
- Diagnostic Center for Population and Animal Health; Michigan State University; USA
| | - P. H. Kass
- Department of Population Health and Reproduction; University of California; USA
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FOWDEN AL, FORHEAD AJ, OUSEY JC. Endocrine adaptations in the foal over the perinatal period. Equine Vet J 2012:130-9. [DOI: 10.1111/j.2042-3306.2011.00505.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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JELLYMAN JK, ALLEN VL, FORHEAD AJ, HOLDSTOCK NB, FOWDEN AL. Hypothalamic-pituitary-adrenal axis function in pony foals after neonatal ACTH-induced glucocorticoid overexposure. Equine Vet J 2012:38-42. [DOI: 10.1111/j.2042-3306.2011.00448.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Plasma aldosterone, vasopressin and atrial natriuretic peptide in hypovolaemia: A preliminary comparative study of neonatal and mature horses. Equine Vet J 2010; 40:64-9. [DOI: 10.2746/042516407x235795] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Panzani S, Villani M, McGladdery A, Magri M, Kindahl H, Galeati G, Martino PA, Veronesi MC. Concentrations of 15-ketodihydro-PGF2alpha, cortisol, and progesterone in the plasma of healthy and pathologic newborn foals. Theriogenology 2009; 72:1032-40. [PMID: 19748663 DOI: 10.1016/j.theriogenology.2009.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 06/08/2009] [Accepted: 06/24/2009] [Indexed: 11/26/2022]
Abstract
Information regarding the plasma hormone profiles of prostaglandins (PGs), cortisol (C), and progesterone (P4) during pathologic processes in newborn foals is scarce. The aim of this study was to determine the plasma concentrations of these hormones in diseased foals (n=40) and healthy at-term foals (n=24) (Equus caballus) during the first 2 weeks of life. Blood samples were collected daily, before any treatment with nonsteroidal drugs in diseased foals, and plasma was analyzed by radioimmunoassay. 15-Ketodihydro-PGF(2alpha) (PGM) was consistently higher in diseased foals than in healthy foals, probably related to roles of PGs in completing organ maturation and/or the presence of oxidative stress or inflammation. Similar trends were observed for C and P4. In diseased newborns, only PGM was significantly higher in nonsurviving foals, although C showed a similar profile. When specific diseases were considered, the levels of PGM and C were lower in premature foals at 12h of life, whereas the concentration of P4 was higher than in controls. The results of this study demonstrate the differences in plasma hormone levels between healthy and pathologic newborn foals, particularly during the first 2 d of life, probably reflecting the inability of diseased foals to cope with the transition between fetal and neonatal life.
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Affiliation(s)
- S Panzani
- Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, University of Milan, Milan, Italy.
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Hart K, Heusner G, Norton N, Barton M. Hypothalamic-Pituitary-Adrenal Axis Assessment in Healthy Term Neonatal Foals Utilizing a Paired Low Dose/High Dose ACTH Stimulation Test. J Vet Intern Med 2009; 23:344-51. [DOI: 10.1111/j.1939-1676.2008.00271.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Panzani S, Villani M, Govoni N, Kindahl H, Faustini M, Romano G, Veronesi M. 15-Ketodihydro-PGF2α and cortisol plasma concentrations in newborn foals after spontaneous or oxytocin-induced parturition. Theriogenology 2009; 71:768-74. [DOI: 10.1016/j.theriogenology.2008.09.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/23/2008] [Accepted: 09/27/2008] [Indexed: 11/26/2022]
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Wong DM, Vo DT, Alcott CJ, Peterson AD, Sponseller BA, Hsu WH. Baseline plasma cortisol and ACTH concentrations and response to low-dose ACTH stimulation testing in ill foals. J Am Vet Med Assoc 2009; 234:126-32. [PMID: 19119977 DOI: 10.2460/javma.234.1.126] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate baseline plasma cortisol and ACTH concentrations and responses to low-dose ACTH stimulation testing in ill foals. DESIGN Cross-sectional study. ANIMALS 58 ill foals. PROCEDURES Baseline cortisol and ACTH concentrations and cortisol concentrations after administration of a low dose of cosyntropin were determined within 6 hours after admission. Foals were assigned to 4 groups on the basis of age (<or=24 hours vs 1 to 56 days) and presence of septicemia (yes vs no). Values were compared among groups and with values previously reported for healthy foals. RESULTS Plasma cortisol concentrations 30 and 60 minutes after cosyntropin administration in foals<or=24 hours old were significantly higher than corresponding cortisol concentrations in older foals. In all 4 groups, plasma cortisol concentration 30 minutes after cosyntropin administration was significantly higher than baseline cortisol concentration or concentration 60 minutes after cosyntropin administration. No differences in baseline cortisol or ACTH concentration or in the ACTH-to-cortisol ratio were detected between groups or when ill foals were compared with healthy foals. A small number of ill foals had low baseline cortisol and ACTH concentrations or low responses to cosyntropin administration, compared with healthy foals. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that most ill foals in the present study population had adequate responses to cosyntropin administration. However, a small subset of ill foals appeared to have dysfunction of the hypothalamic-pituitary-adrenal axis.
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Affiliation(s)
- David M Wong
- Department of Veterinary Clinical Sciences, Iowa State University, Ames, IA 50011, USA
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Wong DM, Vo DT, Alcott CJ, Peterson AD, Brockus CW, Hsu WH. Plasma vasopressin concentrations in healthy foals from birth to 3 months of age. J Vet Intern Med 2008; 22:1259-61. [PMID: 18691367 DOI: 10.1111/j.1939-1676.2008.0165.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Arginine vasopressin (AVP) has received increased attention in equine critical care but there is minimal information of AVP concentration in foals. The clinical usefulness of measuring AVP in ill foals depends on knowledge of age-related changes in AVP concentrations in healthy foals. HYPOTHESIS Plasma AVP concentrations will be significantly different when measured from birth to 3 months of age in healthy foals. ANIMALS Thirteen healthy university-owned foals. METHODS Prospective, observational study. Blood was collected from healthy foals at birth and 3, 5, 7, 10, 14, 21, 28, 42, 56, and 84 days of age. Plasma was harvested and plasma AVP concentrations were determined by radioimmunoassay. RESULTS No statistically significant differences were detected in plasma AVP concentrations over the study period. Plasma AVP concentrations over the entire study period was 6.2+/-2.5 pg/mL. CONCLUSIONS AND CLINICAL IMPORTANCE There was no age-related variation in plasma AVP concentrations detected in healthy foals from birth to 3 months of age suggesting that AVP concentrations are similar across foals of these ages.
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Affiliation(s)
- D M Wong
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, the Iowa State University, Ames, IA 50011, USA.
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Abstract
One of the fundamental skills required for practicing evidence-based medicine is the development of a well-built clinical question, which specifies the patient group or problem, intervention, and outcome of interest. For this purpose, various "levels of evidence" have been developed in the human literature, which rank the validity of evidence. Our established conclusions and advice are thus supported by specific "grades of recommendations," which are intended to give an indication of the "strength" of a clinical recommendation. This article was compiled with these principles in mind.
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John V, Dai H, Talati A, Charnigo RJ, Neuman M, Bada HS. Autonomic alterations in cocaine-exposed neonates following orthostatic stress. Pediatr Res 2007; 61:251-6. [PMID: 17237731 DOI: 10.1203/01.pdr.0000252436.62151.67] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We investigated the effects of prenatal cocaine exposure (PCE) on heart rate (HR) and heart rate variability (HRV) in the presence of orthostatic stress among near- and full-term neonates. PCE infants (n = 21) and controls (n = 23) were enrolled within 120 h of birth. ECG was recorded for an hour during quiet sleep, 30 min in supine position and then 30 min in an inclined position. Linear mixed models were used to analyze HR and HRV in the time domain and wavelet and power spectrum analyses in the frequency domain. PCE infants had tachycardia both before (p = 0.091) and after tilting (p = 0.015), but with a clear interaction between PCE and orthostatic stress (p = 0.049). Compared with controls, PCE infants had a delayed and prolonged reaction to orthostatic stress. There was also a pronounced interaction with regard to log-transformed SDDRR, a measure of HRV (p = 0.049). Controls experienced an instantaneous increase in log (SDDRR) followed by a prompt return to normal levels, while PCE infants had a gradual increase that did not dissipate quickly. Frequency-domain analyses also distinguished between the cocaine-exposed infants and the controls. Results suggest that the effects of PCE on the development of sympathetic and parasympathetic systems could lead to altered cardiovascular function.
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Affiliation(s)
- Vijay John
- Joint Biomedical Engineering Program, University of Tennessee, Memphis, TN 38163, USA
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Valverde A, Giguère S, Sanchez LC, Shih A, Ryan C. Effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function in anesthetized neonatal foals with induced hypotension. Am J Vet Res 2006; 67:1730-7. [PMID: 17014324 DOI: 10.2460/ajvr.67.10.1730] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function and gastric mucosal perfusion in anesthetized foals during isoflurane-induced hypotension. ANIMALS 6 foals that were 1 to 5 days of age. PROCEDURES 6 foals received 3 vasoactive drugs with at least 24 hours between treatments. Treatments consisted of dobutamine (4 and 8 Sang/kg/min), norepinephrine (0.3 and 1.0 Sang/kg/min), and vasopressin (0.3 and 1.0 mU/kg/min) administered IV. Foals were maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia for 30 minutes, and baseline cardiorespiratory variables were recorded. Vasoactive drugs were administered at the low infusion rate for 15 minutes, and cardiorespiratory variables were recorded. Drugs were then administered at the high infusion rate for 15 minutes, and cardiorespiratory variables were recorded a third time. Gastric mucosal perfusion was measured by tonometry at the same time points. RESULTS Dobutamine and norepinephrine administration improved cardiac index. Vascular resistance was increased by norepinephrine and vasopressin administration but decreased by dobutamine at the high infusion rate. Blood pressure was increased by all treatments but was significantly higher during the high infusion rate of norepinephrine. Oxygen delivery was significantly increased by norepinephrine and dobutamine administration; O2 consumption decreased with dobutamine. The O2 extraction ratio was decreased following norepinephrine and dobutamine treatments. The gastric to arterial CO2 gap was significantly increased during administration of vasopressin at the high infusion rate. CONCLUSION AND CLINICAL RELEVANCE Norepinephrine and dobutamine are better alternatives than vasopressin for restoring cardiovascular function and maintaining splanchnic circulation during isoflurane-induced hypotension in neonatal foals.
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Affiliation(s)
- Alexander Valverde
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
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O'Connor SJ, Ousey JC, Gardner DS, Fowden AL, Giussani DA. Development of baroreflex function and hind limb vascular reactivity in the horse fetus. J Physiol 2006; 572:155-64. [PMID: 16469779 PMCID: PMC1779647 DOI: 10.1113/jphysiol.2006.105635] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study investigated, in vivo, the mechanisms underlying the development of cardiovascular function in the horse fetus, with particular relevance to baroreflex function and hind limb vascular arterial reactivity to constrictor agonists. Under general anaesthesia, vascular catheters were inserted and a Transonic flow probe was implanted around one of the metatarsal arteries of 13 horse fetuses, either at 0.6 of gestation (n= 6) or at 0.9 of gestation (n= 7, term approximately 335 days). At least 5 days after surgery, pressor, vasoconstrictor and cardiac chronotropic responses to exogenous bolus doses of phenylephrine, angiotensin II and arginine vasopressin were recorded. Fetal cardiac baroreflex slopes were obtained using the peak pressor and heart rate responses to increasing doses of phenylephrine. Fetal treatment with phenylephrine, angiotensin II and vasopressin produced significant changes in arterial blood pressure, hind limb vascular resistance and heart rate. Pressor and vasopressor responses to all agonists were greater at 0.9 than at 0.6 of gestation; however, fetal cardiac baroreflex sensitivity decreased with advancing gestational age. Correlation analysis revealed that fetal plasma cortisol rather than gestational age was a greater determinant of pressor and vasopressor reactivity. In contrast, gestational age rather than cortisol better determined heart rate and baroreflex responsiveness in the equine fetus. The data show that development of cardiovascular function in the equine fetus occurs via cortisol-dependent and -independent pathways.
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Affiliation(s)
- Susie J O'Connor
- Department of Physiology, University of Cambridge, Cambridge CB2 3EG, UK.
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