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1.
Womens Health Rep (New Rochelle) ; 5(1): 393-403, 2024.
Article in English | MEDLINE | ID: mdl-39035143

ABSTRACT

Introduction: Musculoskeletal injuries (MSKi) are the most common injury type experienced by first-responders and health care providers (HCPs), making them a significant threat to physical and mental well-being. Female reproductive health and injury history has been related to physical fitness in female members of the Canadian Armed Forces. This relationship has not been explored in Canadian protective services personnel (first-responders) or HCPs. Methods: Fifty-seven females employed as firefighters, paramedics, law enforcements, or HCPs completed a physical fitness protocol to assess the following: (1) muscular power (standing long jump and medicine ball throw), (2) muscular strength (4 repetition maximum (4RM) back squats and bench press), (3) muscular endurance (Biering-Sorenson test, single-leg wall sit, and push-ups), (4) flexibility (sit-and-reach), and (5) aerobic capacity (graded treadmill VO2max test). Spearman rho correlation analyses were applied to descriptive analysis, independent-samples t-test, one-way ANCOVA (adjusted by age), and chi-square test. Spearman rho correlation analyses were used to compare physical fitness results for female reproductive health history (e.g., parity status), previous MSKi, and physical activity behaviors (e.g., sports participation). A p value of <0.05 is considered significant. Results: History of childbirth, body composition, and exercise behaviors were related to physical fitness (i.e., standing long jump, Biering-Sorenson test, bench press, and back squat) in law enforcement, firefighting, paramedicine, and health care personnel. Conclusions: Physical training programs aimed at supporting parous first-responders or HCPs should emphasize lower body power, lower body strength, and upper body strength.

2.
Nat Commun ; 15(1): 2054, 2024 Mar 06.
Article in English | MEDLINE | ID: mdl-38448430

ABSTRACT

Antibody engineering can tailor the design and activities of therapeutic antibodies for better efficiency or other advantageous clinical properties. Here we report the development of ISB 1442, a fully human bispecific antibody designed to re-establish synthetic immunity in CD38+ hematological malignancies. ISB 1442 consists of two anti-CD38 arms targeting two distinct epitopes that preferentially drive binding to tumor cells and enable avidity-induced blocking of proximal CD47 receptors on the same cell while preventing on-target off-tumor binding on healthy cells. The Fc portion of ISB 1442 is engineered to enhance complement dependent cytotoxicity, antibody dependent cell cytotoxicity and antibody dependent cell phagocytosis. ISB 1442 thus represents a CD47-BsAb combining biparatopic targeting of a tumor associated antigen with engineered enhancement of antibody effector function to overcome potential resistance mechanisms that hamper treatment of myeloma with monospecific anti-CD38 antibodies. ISB 1442 is currently in a Phase I clinical trial in relapsed refractory multiple myeloma.


Subject(s)
Antibodies, Bispecific , Hematologic Neoplasms , Multiple Myeloma , Humans , Multiple Myeloma/drug therapy , CD47 Antigen , Antibodies, Bispecific/pharmacology , Antibodies, Bispecific/therapeutic use , Antibody-Dependent Cell Cytotoxicity
3.
J Bone Oncol ; 29: 100375, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34131559

ABSTRACT

Optimum management of patients with cancer during the COVID-19 pandemic has proved extremely challenging. Patients, clinicians and hospital authorities have had to balance the risks to patients of attending hospital, many of whom are especially vulnerable, with the risks of delaying or modifying cancer treatment. Those whose care has been significantly impacted include patients suffering from the effects of cancer on bone, where delivering the usual standard of care for bone support has often not been possible and clinicians have been forced to seek alternative options for adequate management. At a virtual meeting of the Cancer and Bone Society in July 2020, an expert group shared experiences and solutions to this challenge, following which a questionnaire was sent internationally to the symposium's participants, to explore the issues faced and solutions offered. 70 respondents, from 9 countries (majority USA, 39%, followed by UK, 19%) included 50 clinicians, spread across a diverse range of specialties (but with a high proportion, 64%, of medical oncologists) and 20 who classified themselves as non-clinical (solely lab-based). Spread of clinician specialty across tumour types was breast (65%), prostate (27%), followed by renal, myeloma and melanoma. Analysis showed that management of metastatic bone disease in all solid tumour types and myeloma, adjuvant bisphosphonate breast cancer therapy and cancer treatment induced bone loss, was substantially impacted. Respondents reported delays to routine CT scans (58%), standard bone scans (48%) and MRI scans (46%), though emergency scans were less affected. Delays in palliative radiotherapy for bone pain were reported by 31% of respondents with treatments often involving only a single dose without fractionation. Delays to, or cancellation of, prophylactic surgery for bone pain were reported by 35% of respondents. Access to treatments with intravenous bisphosphonates and subcutaneous denosumab was a major problem, mitigated by provision of drug administration at home or in a local clinic, reduced frequency of administration or switching to oral bisphosphonates taken at home. The questionnaire also revealed damaging delays or complete stopping of both clinical and laboratory research. In addition to an analysis of the questionnaire, this paper presents a rationale and recommendations for adaptation of the normal guidelines for protection of bone health during the pandemic.

4.
Transl Psychiatry ; 9(1): 81, 2019 02 11.
Article in English | MEDLINE | ID: mdl-30745563

ABSTRACT

Abnormal levels of dopamine (DA) are thought to contribute to several neurological and psychiatric disorders including drug addiction. Extracellular DA levels are regulated primarily via reuptake by the DA transporter (DAT). Amphetamine, a potent psychostimulant, increases extracellular DA by inducing efflux through DAT. Recently, we discovered that G protein ßγ subunits (Gßγ) interact with DAT, and that in vitro activation of Gßγ promotes DAT-mediated efflux. Here, we investigated the role of Gßγ in the actions of amphetamine in DA neurons in culture, ex vivo nucleus accumbens (NAc), and freely moving rats. Activation of Gßγ with the peptide myr-Ser-Ile-Arg-Lys-Ala-Leu-Asn-Ile-Leu-Gly-Tyr-Pro-Asp-Tyr-Asp (mSIRK) in the NAc potentiated amphetamine-induced hyperlocomotion, but not cocaine-induced hyperlocomotion, and systemic or intra-accumbal administration of the Gßγ inhibitor gallein attenuated amphetamine-induced, but not cocaine-induced hyperlocomotion. Infusion into the NAc of a TAT-fused peptide that targets the Gßγ-binding site on DAT (TAT-DATct1) also attenuated amphetamine-induced but not cocaine-induced hyperlocomotion. In DA neurons in culture, inhibition of Gßγ with gallein or blockade of the Gßγ-DAT interaction with the TAT-DATct1 peptide decreased amphetamine-induced DA efflux. Furthermore, activation of Gßγ with mSIRK potentiated and inhibition of Gßγ with gallein reduced amphetamine-induced increases of extracellular DA in the NAc in vitro and in freely moving rats. Finally, systemic or intra-accumbal inhibition of Gßγ with gallein blocked the development of amphetamine-induced, but not cocaine-induced place preference. Collectively, these results suggest that interaction between Gßγ and DAT plays a critical role in the actions of amphetamine and presents a novel target for modulating the actions of amphetamine in vivo.


Subject(s)
Amphetamine/pharmacology , Central Nervous System Stimulants/pharmacology , Dopamine Plasma Membrane Transport Proteins/metabolism , Dopamine/metabolism , GTP-Binding Protein beta Subunits/metabolism , GTP-Binding Protein gamma Subunits/metabolism , Amphetamine/adverse effects , Animals , Central Nervous System Stimulants/adverse effects , Cocaine/administration & dosage , Dopaminergic Neurons/metabolism , Male , Motor Activity/drug effects , Nucleus Accumbens/metabolism , Rats , Rats, Sprague-Dawley
5.
Mol Cancer ; 16(1): 49, 2017 02 28.
Article in English | MEDLINE | ID: mdl-28241871

ABSTRACT

Matrix metalloproteinases (MMPs) play a critical role in cancer pathogenesis, including tumor growth and osteolysis within the bone marrow microenvironment. However, the anti-tumor effects of MMPs are poorly understood, yet have significant implications for the therapeutic potential of targeting MMPs. Host derived MMP-7 has previously been shown to support the growth of bone metastatic breast and prostate cancer. In contrast and underscoring the complexity of MMP biology, here we identified a tumor-suppressive role for host MMP-7 in the progression of multiple myeloma in vivo. An increase in tumor burden and osteolytic bone disease was observed in myeloma-bearing MMP-7 deficient mice, as compared to wild-type controls. We observed that systemic MMP-7 activity was reduced in tumor-bearing mice and, in patients with multiple myeloma this reduced activity was concomitant with increased levels of the endogenous MMP inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1). Our studies have identified an unexpected tumour-suppressive role for host-derived MMP-7 in myeloma bone disease in vivo, and highlight the importance of elucidating the effect of individual MMPs in a disease-specific context.


Subject(s)
Bone Neoplasms/secondary , Matrix Metalloproteinase 7/genetics , Matrix Metalloproteinase 7/metabolism , Multiple Myeloma/pathology , Animals , Bone Neoplasms/genetics , Bone Neoplasms/metabolism , Bone Neoplasms/pathology , Cell Line, Tumor , Cell Survival , Disease Progression , Gene Knockout Techniques , Humans , Mice , Multiple Myeloma/genetics , Multiple Myeloma/metabolism , Neoplasm Transplantation , Tumor Microenvironment
6.
Br J Cancer ; 116(2): 227-236, 2017 Jan 17.
Article in English | MEDLINE | ID: mdl-28006818

ABSTRACT

BACKGROUND: Recent evidence suggests that bone-related parameters are the main prognostic factors for overall survival in advanced prostate cancer (PCa), with elevated circulating levels of alkaline phosphatase (ALP) thought to reflect the dysregulated bone formation accompanying distant metastases. We have identified that PCa cells express ALPL, the gene that encodes for tissue nonspecific ALP, and hypothesised that tumour-derived ALPL may contribute to disease progression. METHODS: Functional effects of ALPL inhibition were investigated in metastatic PCa cell lines. ALPL gene expression was analysed from published PCa data sets, and correlated with disease-free survival and metastasis. RESULTS: ALPL expression was increased in PCa cells from metastatic sites. A reduction in tumour-derived ALPL expression or ALP activity increased cell death, mesenchymal-to-epithelial transition and reduced migration. Alkaline phosphatase activity was decreased by the EMT repressor Snail. In men with PCa, tumour-derived ALPL correlated with EMT markers, and high ALPL expression was associated with a significant reduction in disease-free survival. CONCLUSIONS: Our studies reveal the function of tumour-derived ALPL in regulating cell death and epithelial plasticity, and demonstrate a strong association between ALPL expression in PCa cells and metastasis or disease-free survival, thus identifying tumour-derived ALPL as a major contributor to the pathogenesis of PCa progression.


Subject(s)
Alkaline Phosphatase/physiology , Cell Proliferation/genetics , Epithelial-Mesenchymal Transition/genetics , Prostatic Neoplasms/pathology , Prostatic Neoplasms/therapy , Alkaline Phosphatase/genetics , Animals , Cell Death/genetics , Cell Movement/genetics , Cells, Cultured , Disease Progression , Disease-Free Survival , HEK293 Cells , Humans , Male , Mice , Neoplasm Metastasis , Prostatic Neoplasms/genetics
7.
BMJ Case Rep ; 20152015 Sep 07.
Article in English | MEDLINE | ID: mdl-26347235

ABSTRACT

We describe the case of a young man who developed syncope after using a high strength formulation of topical minoxidil as a hair growth restorer. Other potential cardiovascular and endocrine causes were excluded, and his symptoms resolved on discontinuation of the product. While syncope is a recognised side effect of using this powerful systemic antihypertensive agent, few cases are documented in the literature, which we illustrate in our discussion.


Subject(s)
Alopecia/drug therapy , Hair , Minoxidil/adverse effects , Syncope/chemically induced , Administration, Topical , Adult , Antihypertensive Agents/adverse effects , Humans , Male , Minoxidil/administration & dosage
9.
Br J Pharmacol ; 171(16): 3765-76, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24750110

ABSTRACT

Multiple myeloma is a neoplastic disorder of plasma cells characterized by clonal proliferation within the bone marrow. One of the major clinical features of multiple myeloma is the destructive osteolytic bone disease that occurs in the majority of patients. Myeloma bone disease is associated with increased osteoclast activity and suppression of osteoblastogenesis. Bisphosphonates have been the mainstay of treatment for many years; however, their use is limited by their inability to repair existing bone loss. Therefore, research into novel approaches for the treatment of myeloma bone disease is of the utmost importance. This review will discuss the current advances in our understanding of osteoclast stimulation and osteoblast suppression mechanisms in myeloma bone disease and the treatments that are under development to target this destructive and debilitating feature of myeloma.


Subject(s)
Bone Diseases/drug therapy , Multiple Myeloma/drug therapy , Animals , Bone Density Conservation Agents/pharmacology , Bone Density Conservation Agents/therapeutic use , Bone Diseases/etiology , Bone Diseases/immunology , Bone Diseases/metabolism , Diphosphonates/pharmacology , Diphosphonates/therapeutic use , Humans , Immunologic Factors/pharmacology , Immunologic Factors/therapeutic use , Multiple Myeloma/complications , Multiple Myeloma/immunology , Multiple Myeloma/metabolism , Protease Inhibitors/pharmacology , Protease Inhibitors/therapeutic use , Signal Transduction
12.
J Crohns Colitis ; 4(4): 405-12, 2010 Oct.
Article in English | MEDLINE | ID: mdl-21122536

ABSTRACT

BACKGROUND: Inflammatory bowel disease (IBD), a paradigm of chronic illness, requires for its safe clinical management ready access to complete information, not always possible using paper records. AIM: To develop an IBD database (DB) for both individual patient management and collating information across centres. METHODS: Access® based, with a minimum dataset. RESULTS: Prospectively collected data for 11,432 patients from 21 centres. PROFILE DIAGNOSIS: Ulcerative colitis (UC) 56%, Crohn's disease (CD) 40%, indeterminate colitis 4%. M:F ratio: UC 1.08:1, CD 0.72:1. Median age at diagnosis: UC 39, CD 30 years. Operated: UC 16%, CD 47%. Thiopurine use: UC 16%, CD 29%. IBD related mortality: 0.74%. DISCUSSION: A snapshot of this large IBD cohort shows the disease profile across the UK is similar to other large series. Unexpected gaps, sometimes large emerged (e.g. data on smoking and immunosuppression) highlighting the need for clear definition, consistency and completeness of data collection. Clinical management is made easier by the 'at a glance' summary, automated clinic letters, and facility for monitoring and audit, but the time required limited its 'real-time' use. CONCLUSION: Our experience shows it is possible to collect data from centres across the country which truly reflects clinical practice. We have learned as much from the process itself as from the data, principally, information needs to be well defined, validated at entry, and updated at every visit, a time consuming sequence which we had underestimated. Our lessons learned may help inform the development of a national database, and support national IBD standards and audit.


Subject(s)
Databases, Factual , Inflammatory Bowel Diseases/epidemiology , Colectomy , Colitis/drug therapy , Colitis/epidemiology , Colitis/surgery , Colitis/therapy , Colitis, Ulcerative/epidemiology , Colitis, Ulcerative/therapy , Crohn Disease/drug therapy , Crohn Disease/epidemiology , Crohn Disease/surgery , Crohn Disease/therapy , Data Collection , Humans , Immunosuppressive Agents/therapeutic use , Inflammatory Bowel Diseases/drug therapy , Inflammatory Bowel Diseases/surgery , Inflammatory Bowel Diseases/therapy , Severity of Illness Index , United Kingdom/epidemiology
13.
Leukemia ; 21(4): 805-12, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17315027

ABSTRACT

The growth and survival of myeloma cells is critically regulated by cells of the bone marrow microenvironment, including osteoblasts. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent inducer of myeloma cell apoptosis, however, this antimyeloma activity is inhibited by osteoprotegerin (OPG) released from osteoblasts. Therefore, we hypothesized that specific agonists of TRAIL death receptors would not be inhibited by OPG released from osteoblasts and thus may represent a novel therapeutic approach in multiple myeloma. In the present study, TRAIL-induced apoptosis was demonstrated to be mediated through both DR4 and DR5. Specific agonist antibodies to DR4 or DR5 dose-dependently induced myeloma cell apoptosis, which was not prevented by OPG or by medium conditioned by osteoblasts. Co-culture of myeloma cells with osteoblasts protected against TRAIL-induced apoptosis of myeloma cells, and this protective effect was due to OPG. In contrast, the co-culture of myeloma cells with osteoblasts had no protective effect on apoptosis induced by specific agonists of DR4 or DR5. TRAIL has been proposed as a potential antitumour therapy, but within the bone marrow microenvironment OPG may interfere with the action of TRAIL. Specific agonists of TRAIL death receptors would not be subject to this inhibition and thus may provide an alternative specific antimyeloma therapy.


Subject(s)
Apoptosis/physiology , Bone Marrow Cells/physiology , Multiple Myeloma/pathology , Osteoprotegerin/pharmacology , Receptors, TNF-Related Apoptosis-Inducing Ligand/drug effects , Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics , Amino Acid Chloromethyl Ketones/pharmacology , Cell Line, Tumor , Flow Cytometry , Gene Expression Regulation, Neoplastic , Humans , Osteoblasts/drug effects , Osteoblasts/physiology , Receptors, TNF-Related Apoptosis-Inducing Ligand/agonists , Reverse Transcriptase Polymerase Chain Reaction
15.
Pflugers Arch ; 450(5): 298-306, 2005 Aug.
Article in English | MEDLINE | ID: mdl-15931536

ABSTRACT

OBJECTIVE: The aims of this study were to compare and contrast the development of the cardiac baroreflex and endocrine responses to acute hypotensive stress in healthy newborn pony foals and lambs during the first two weeks of postnatal life. METHODS: Under general anaesthesia, seven Welsh pony foals and six Welsh Mountain lambs were catheterised with hind limb artery and vein catheters. Following post-surgical recovery, at 1 week and 2 weeks of age, blood pressures of the animals were raised and lowered acutely by intravenous infusion of phenylephrine and sodium nitroprusside, respectively. During hypotension, blood samples were taken for measurement of plasma hormones associated with activation of the stress axis. RESULTS: Basal arterial blood pressure increased significantly (P<0.05) between week 1 and week 2 in the absence of any significant change in basal heart rate in foals and with a significant reduction in basal heart rate in lambs. In foals, the slope of the heart rate-blood pressure relationship decreased in response to acute hypertension, and it increased in response to acute hypotension, from week 1 to week 2 (all P<0.05). In contrast, in lambs, the slope of the heart rate-blood pressure relationship decreased with both acute hypertension and acute hypotension from week 1 to week 2 (all P<0.05). In foals, there were significant increases in plasma concentrations of noradrenaline, neuropeptide Y (NPY), vasopressin, adrenocorticotrophic hormone (ACTH) and cortisol in response to hypotension (P<0.05). In lambs, there were also significant increases in plasma concentrations of ACTH and cortisol during hypotension. Plasma concentrations of noradrenaline, NPY and vasopressin were not measured during hypotension in lambs. In foals, although the magnitude of the ACTH response to hypotension was smaller at week 2 than week 1, the increment in plasma cortisol was similar in the two age groups. In contrast, in lambs, the profile of both the ACTH and cortisol responses was similar at week 1 and week 2. CONCLUSION: These data suggest that the increase in basal arterial blood pressure in the foal and the lamb during the first 2 weeks of postnatal life is accompanied by differential maturational changes in the vagal and sympathetic components of the cardiac baroreflex between the two species. These developmental cardiac baroreflex changes occur together with increased adrenocortical responsiveness to acute hypotensive stress, which appears comparatively more mature in lambs than in foals.


Subject(s)
Animals, Newborn/physiology , Baroreflex/physiology , Endocrine System/physiology , Hypotension/physiopathology , Stress, Physiological/physiopathology , Adrenocorticotropic Hormone/blood , Animals , Arginine Vasopressin/blood , Epinephrine/blood , Heart/drug effects , Heart/physiopathology , Heart Rate/physiology , Horses , Hydrocortisone/blood , Hypertension/physiopathology , Hypotension/chemically induced , Neuropeptide Y/blood , Nitroprusside , Norepinephrine/blood , Phenylephrine/pharmacology , Sheep
16.
J Physiol ; 567(Pt 2): 673-88, 2005 Sep 01.
Article in English | MEDLINE | ID: mdl-15975982

ABSTRACT

In sheep, direct fetal treatment with dexamethasone alters basal cardiovascular function and the cardiovascular response to acute hypoxaemia. However, in human clinical practice, dexamethasone is administered to the mother, not to the fetus. Hence, this study investigated physiological responses to acute hypoxaemia in fetal sheep during and following maternal treatment with dexamethasone in doses and at dose intervals used in human clinical practice. Under anaesthesia, 18 fetal sheep were instrumented with vascular and amniotic catheters, a carotid flow probe and a femoral flow probe at 118 days gestation (term ca 145 days). Following 6 days recovery at 124 days gestation, 10 ewes received dexamethasone (2 x 12 mg daily i.m. injections in saline). The remaining animals were saline-injected as age-matched controls. Two episodes of hypoxaemia (H) were induced in all animals by reducing the maternal F(IO2)for 1 h (H1, 8 h after the second injection; H2, 3 days after the second injection). In fetuses whose mothers received saline, hypoxaemia induced significant increases in fetal arterial blood pressure, carotid blood flow and carotid vascular conductance and femoral vascular resistance, significant falls in femoral blood flow and femoral vascular conductance and transient bradycardia. These cardiovascular responses were accompanied by a fall in arterial pH, increases in blood glucose and blood lactate concentrations and increased plasma concentrations of catecholamines. In fetuses whose mothers were treated with dexamethasone, bradycardia persisted throughout hypoxaemia, the magnitude of the femoral vasoconstriction, the glycaemic, lactacidaemic and acidaemic responses and the plasma concentration of neuropeptide Y (NPY) were all enhanced during H1. However, during H2, all of these physiological responses were similar to saline controls. In dexamethasone fetuses, the increase in plasma adrenaline was attenuated during H1 and the increase in carotid vascular conductance during hypoxaemia failed to reach statistical significance both during H1 and during H2. These data show that maternal treatment with dexamethasone in doses and intervals used in human obstetric practice modified the fetal cardiovascular, metabolic and endocrine defence responses to acute hypoxaemia. Furthermore, dexamethasone-induced alterations to these defences depended on whether the hypoxaemic challenge occurred during or following maternal dexamethasone treatment.


Subject(s)
Blood Pressure/drug effects , Dexamethasone/administration & dosage , Endocrine System/drug effects , Fetus/drug effects , Heart Rate/drug effects , Hormones/blood , Hypoxia/embryology , Hypoxia/physiopathology , Acute Disease , Animals , Blood Glucose/analysis , Endocrine System/metabolism , Female , Fetus/blood supply , Fetus/physiopathology , Humans , Maternal-Fetal Exchange , Pregnancy , Sheep
17.
BJOG ; 112(7): 889-96, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15957988

ABSTRACT

OBJECTIVE: This study tested the hypothesis that pregnancy affects the cardiovascular responses to hypoxia by altering the outputs of the peripheral components of the stress system and independent of changes in P(a)CO(2). DESIGN: Comparison of cardiovascular and endocrine responses to acute isocapnic hypoxia between pregnant and non-pregnant ewes. SETTING: Experimental laboratory. SAMPLE: Fifteen pregnant (118 days of gestation; term is ca. 145 days) and 8 non-pregnant sheep. METHODS: Chronically instrumented pregnant and non-pregnant ewes were subjected to 1 hour normoxia, 1 hour of acute systemic isocapnic hypoxia and 1 hour recovery. MAIN OUTCOME MEASURES: Arterial blood pressure, heart rate, femoral blood flow and femoral vascular conductance were recorded continuously throughout and arterial blood samples were taken during normoxia, hypoxia and recovery for the measurement of blood gas, metabolic and endocrine status. RESULTS: Basal blood pressure and blood glucose and lactate concentrations were lower in pregnant animals (P < 0.05). In contrast, basal cardiovascular variables and plasma concentrations of noradrenaline, adrenaline, neuropeptide Y, adrenocorticotropic hormone (ACTH) and cortisol were similar in pregnant and non-pregnant ewes. During hypoxia similar reductions in P(a)O(2) occurred in pregnant and non-pregnant animals, without alterations in P(a)CO(2) or pH(a). In non-pregnant ewes, acute hypoxia induced a transient increase in arterial pressure and sustained tachycardia without significant changes in femoral haemodynamics. Pregnancy attenuated the cardiovascular response, significantly diminishing the magnitude of the increment in heart rate throughout the hypoxic challenge (P < 0.001). However, hypoxia did not induce significant changes in blood metabolites or in plasma concentrations of any stress hormone measured in either pregnant or non-pregnant animals. CONCLUSION: Pregnancy not only affects basal but also stimulated cardiovascular function in the mother. The diminished chronotropic response to hypoxia in pregnancy is mediated via mechanisms independent of changes in P(a)CO(2) or in plasma concentrations of hormones or metabolites associated with activation of the stress system.


Subject(s)
Cardiovascular Physiological Phenomena , Hypoxia/physiopathology , Pregnancy, Animal/physiology , Analysis of Variance , Animals , Blood Flow Velocity/physiology , Blood Pressure/physiology , Carbon Dioxide/blood , Consciousness/physiology , Female , Heart Rate/physiology , Hydrogen-Ion Concentration , Partial Pressure , Pregnancy , Sheep, Domestic
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