bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of hindlimb unloading on sympathetic vasoconstriction in resting and contracting skeletal muscle (1165.3)
Authors: Just Timothy , Jendzjowsky Nicholas , DeLorey Darren 
Published: June 2021

We hypothesized that hindlimb unloading (HU) would increase sympathetic vasoconstrictor responsiveness and diminish nitric oxide (NO) mediated inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle. Sprague‐Dawley rats (n=21) were randomized to sedentary time‐control (S; n = 9) or HU (n = 12) groups for 21d. Rats were anesthetized and instrumented for stimulation of the lumbar sympathetic chain and measurement of femoral vascular conductance (FVC). Sympathetic stimulations were delivered at 2Hz and 5Hz at rest and during contraction of the triceps surae muscles at 60% of maximal contractile force before and after NO synthase blockade (L‐NAME; 5mg·kg‐1 IV). The percentage decrease in FVC in response to sympathetic stimulation was not different (P > 0.05) between groups at rest (HU: 2Hz: ‐29 ± 10%; 5Hz: ‐50 ± 12%; S: 2Hz: ‐26 ± 10%, 5Hz: ‐44 ± 8%) and during contraction (HU: 2Hz: ‐9 ± 4%; 5Hz: ‐22 ± 7%; S: 2Hz: ‐7 ± 5%; 5Hz:‐18 ± 7%). In the presence of L‐NAME the vasoconstrictor response was not different (P > 0.05) between groups at rest (HU: 2Hz: ‐43 ± 7%; 5Hz: ‐63 ± 10%; S: 2Hz: ‐42 ± 8%; 5Hz: ‐57 ± 6%) and during contraction (HU: 2Hz: ‐12 ± 3%; 5Hz: ‐24 ± 6%; S: 2Hz: ‐12 ± 4%; 5Hz: ‐28 ± 8%). We conclude that HU does not alter sympathetic vasoconstrictor responsiveness or NO mediated inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle.Grant Funding Source: Supported by NSERC, Canada.
Ketorolac attenuates the blood pressure response to dynamic exercise in peripheral arterial disease patients (1165.5)
Authors: Muller Matthew , Drew Rachel , Sinoway Lawrence 
Published: June 2021

Humans with peripheral arterial disease (PAD) have an augmented exercise pressor reflex (EPR) but the metabolites responsible for this augmented response are unknown. We tested the hypothesis that intravenous infusion of ketorolac (a COX inhibitor) would attenuate the rise in mean arterial blood pressure (MAP) and heart rate (HR) in response to low‐intensity plantar flexion exercise in humans with PAD. Six PAD patients underwent four minutes of one‐legged rhythmic plantar flexion (30 contractions/min) in the supine posture. The workload began at 0.5 kg and progressed by 0.5 kg each minute. MAP and HR were measured on a beat‐by‐beat basis; changes from baseline in response to exercise were determined for both control and ketorolac conditions. Ketorolac did not affect resting MAP (97 ± 3 versus 94 ± 4 mmHg) or HR (58 ± 2 versus 55 ± 2 bpm). During the first 20 seconds of exercise with the most diseased leg, ΔMAP was significantly attenuated with ketorolac (2 ± 2 mmHg) as compared to control (8 ± 2 mmHg) but ΔHR was similar (7 ± 2 versus 6 ± 1 bpm). During the second and third minutes of exercise, ΔMAP was also significantly attenuated under ketorolac. These data indicate that prostaglandins contribute to the augmented EPR in patients with PAD. Because this response occurred at very low workloads, we speculate that muscle mechanoreceptors are sensitized by cycolooxyegnase products under conditions of chronic limb ischemia.Grant Funding Source: Supported by NIH P01 HL096570 (LIS) and UL1 TR000127 (LIS)
Group III/IV muscle afferents are important for the pressor response to dynamic exercise in healthy humans (1165.9)
Authors: Vianna Lauro , Barbosa Thales , Fernandes Igor , Magalhães Nisval , Cavalcanti Ismar , Secher Niels , Nóbrega Antonio 
Published: June 2021

The onset of dynamic exercise typically exhibits a triphasic blood pressure (BP) response, consisting of an initial rise (0‐3s) followed by a transient drop below resting levels (4‐10s) and then a sustained increase (>10s). We investigated the role of skeletal muscle afferents in modulating the dynamics of BP at the onset of exercise. Beat‐to‐beat BP (brachial artery), heart rate (HR), stroke volume (SV), cardiac output (CO) were continuously monitored in 8 healthy men (28±3 yr) while performing leg cycling exercise (80W) under control (CTRL) and lumbar intrathecal fentanyl (FENT) (impairing cephalad projection of opioid receptor sensitive muscle afferents). To evaluate whether cephalad migration of fentanyl affected cardiovascular control centers, we assessed the pressor response to handgrip exercise in both conditions. At the exercise onset, mean BP increased from baseline in the first 3s (+5±1 mmHg, P<0.05) and decreased to a nadir at 10s (‐4±3 mmHg, P<0.05). Fentanyl did not affect BP response during the first 10s, but blunted its increase thereafter (CTRL: +9±3 vs. FENT: 0±2 mmHg at 50s; P<0.05). HR, SV and CO responses to exercise were not affected by fentanyl. Similar mean BP responses to static handgrip in both conditions indicated that cephalad migration of fentanyl was avoided. Our findings demonstrate an important contribution of group III/IV muscle afferent fibers to BP response to leg cycling exercise.Grant Funding Source: Supported by the Brazilian Science Without Borders Program
Pyridostigmine enhances vagal influence to the heart but increases renal sympathetic nerve activity in anesthetized rats (1169.14)
Authors: Aguiar Carlos Alberto , Santos Fernanda , Salgado Helio , Fazan Rubens 
Published: June 2021

We evaluated effect of acute blockade of plasma acetylcholinesterase with pyridostigmine (PYR) on cardiac sympatho‐vagal balance and on electrical activity of the renal sympathetic nerve (RSN) in anesthetized rats.Cardiac sympathetic and vagal tone were assessed in urethane anesthetized rats by heart rate (HR) responses to propranolol (2 mg/kg, N=14) or methyl‐atropine (1 mg/kg, N=18), respectively, 60 min after treatment with PYR (0.25 mg/kg iv) or saline.Other rats, also under urethane anesthesia, were instrumented for AP and RSN activity recordings. After basal recording the rats received PYR (0.25 mg/kg, iv N=6) or saline (N=4) and the experiment last for 1h.PYR elicited a prompt bradycardia (‐73±6 bpm) that partially recovered, but HR remained lower (387±7 vs 445±9 bpm), 1h after treatment. Sympathetic tone was lower (31±6 vs 69±7 bpm) and vagal tone was higher (86±7 vs 44±5 bpm) in rats treated with PYR.A progressive increase in RSN activity, with no change in BP, was observed after treatment with PYR (40±3, 81±26 and 87±6% at 20, 40 and 60 min after PYR). No change in RSN activity was observed in rats treated with saline.Acute treatment with PYR was effective in enhance parasympathetic and reduce sympathetic tonic influence to the heart. Nevertheless, RSN recording revealed an acute increase in sympathetic nerve traffic elicited by PYR.Grant Funding Source: Supported by FAPESP, CAPES, CNPq.
A pulse‐based diet and exercise training in women with polycystic ovarian syndrome: effects on body composition, blood lipids and reproductive measures (117.5)
Authors: McBreairty Laura , Zello Gordon , Rooke Julianne , Serrao Shani , Pierson Roger , Chizen Donna , Chilibeck Philip 
Published: June 2021

Polycystic ovarian syndrome (PCOS) is an endocrine disorder that predisposes women to an increased risk of heart disease, diabetes, infertility and endometrial cancer with an annual cost of $4 billion in the United States. We hypothesized that a pulse‐based diet (e.g. beans, lentils) would have a positive effect on body composition as analyzed by dual energy X‐ray absorptiometry, reproductive measures and serum lipid profiles. Twenty‐five women with PCOS aged 18‐35y with a mean BMI of 31 were randomly assigned to groups receiving a pulse‐based diet (n=14) or the National Cholesterol Education Program (NCEP) therapeutic lifestyle changes (TLC) diet (n=11) for 16 wks while participating in an exercise program. Following the intervention, both groups lost body mass (p<0.05; Pulse ‐2.4 vs TLC ‐3.0 kg), percent fat mass (Pulse ‐1.0 vs TLC ‐1.6 %) and trunk fat mass (Pulse ‐1.0 vs TLC ‐1.7 kg). No changes were observed in lean body mass between groups. Both dietary interventions also resulted in more women exhibiting regular menstrual patterns (p<0.001) and a tendency towards a decreased antral follicle count in the right ovary (p=0.06); however, only the pulse diet reduced total cholesterol to HDL ratio (4.2 to 3.8 p<0.005). As hypothesized, a pulse‐based diet reduced body fat, and improved reproductive measures and serum lipid profiles. Thus, early diagnosis and dietary/exercise interventions are important in alleviating both the personal health and economic costs associated with PCOS.Grant Funding Source: Supported by the Saskatchewan Pulse Growers and Agriculture Agri‐Food Canada (Cluster Program)
The aqueous calyx extract of Hibiscus sabdariffa may lower blood pressure and pulse rate by sympathetic nervous system‐dependent mechanism(s) (1170.11)
Authors: Mojiminiyi Frank , Aliyu Buhari , Oyeniyi Yinka , Isezuo Simeon , Alada AbdulRasak 
Published: June 2021

This study tested the hypothesis that the hypotensive effect of the aqueous calyx extract of Hibiscus sabdariffa (HS) may be sympathetically mediated. Following ethical approval and informed consent, the cold pressor test (CPT) was performed in 20 healthy subjects before and after the oral administration of 15mg/Kg HS. The blood pressure (BP) and pulse rate (PR) responses were measured digitally. Mean arterial pressure (MAP; taken as representative BP) was calculated. Experiments were performed in accordance with the Principles of the Declaration of Helsinki. Results are expressed as mean ±SEM. P<0.05 was considered significant. CPT done in the absence of HS resulted in a significant rise in BP and PR (111.1 ± 2.1mmHg and 100.8 ± 2.0/min) from the basal values (97.9±1.9mmHg and 87.8±2.1/min; P<0.0001 respectively). In the presence of HS however, these fell significantly (101.5±1.8mmHg and 92.4±2.0/min; P<0.0001 respectively). These results suggest that the hypotensive effect of HS may be due to an attenuation of the discharge of the sympathetic nervous system.Grant Funding Source: Personal Funds
Effect of device guided slow deep breathing on central sympathetic outflow and arterial baroreflex sensitivity in young healthy individuals (1170.4)
Authors: Shantsila Alena , Adlan Ahmed M , Lip Gregory , Pickering Anthony , Paton Julian , Fisher James 
Published: June 2021

We sought to investigate whether device guided slow deep breathing (SDB; RESPeRATE©) influences muscle sympathetic nerve activity (MSNA) and spontaneous baroreflex sensitivity in young healthy individuals. Following a 10 min supine baseline period, 9 men (29±7 years, body mass index 24±2 kg/m2; mean±SD) undertook 10 min of SDB while respiratory frequency (strain gauge pneumobelt), partial pressure of end‐tidal carbon dioxide (PETCO2), blood pressure (BP; finger photoplethymography), heart rate (HR; ECG) and MSNA (microneurography) were continuously monitored. Indices of arterial baroreflex control of the heart (sequence technique) and MSNA burst incidence were calculated. Respiratory rate was reduced from 12±2 to 6.2±0.7 breaths/min (P<0.001) during SDB, while PETCO2 (P=0.50), and mean BP (P=0.40) were unchanged. SDB significantly reduced MSNA burst incidence (i.e., percentage of cardiac cycles associated with a MSNA burst) from 25 (20‐38) to 20 (18‐33) (median and interquartile range; P=0.04). Neither cardiac (systolic BP‐RR interval; P=0.26) or sympathetic (P=0.95) baroreflex sensitivity were changed with SDB. Thus, reductions in MSNA burst incidence with device guided SDB in young healthy individuals appear not to be secondary to a change in baroreflex sensitivity, but may reflect an increase in lung inflation afferent input and/or a reduction in central respiratory‐sympathetic coupling.Grant Funding Source: Supported by British Heart Foundation
The carbon dioxide reserve is reduced and chemoreflex sensitivity is increased in the morning compared to the evening and afternoon in participants with sleep apnea (1178.7)
Authors: El Chami Mohamad , Syed Ziauddin , Shaheen David , Ivers Blake , Badr M. Safwan , Lin Ho‐Sheng , Mateika Jason 
Published: June 2021

Purpose: Clinical studies have indicated that breathing instability in patients with sleep apnea is increased in the morning independent of sleep stage. Upper airway collapsibility and chemoreflex responses to hypoxia/hypercapnia have a major influence on breathing stability during sleep. Thus we hypothesized that these parameters would be greater in the morning compared to the evening and afternoon.Methods: Five participants with sleep apnea slept for 3 hours in the evening, morning and afternoon while upper airway patency was maintained with positive airway pressure. Intermittently the pressure was reduced for a period of 3‐5 breaths until the airway collapsed. On a separate occasion the protocol was repeated and the threshold (i.e. apneic threshold) and sensitivity of the chemoreflex response to carbon dioxide was determined by applying 3‐minute periods of mechanical ventilation followed by 5 minutes of recovery.Results: Upper airway collapsibility was not significantly greater in the morning compared to the other sessions (1.87 ± 2.48 vs. ‐ 0.22 ± 1.10 cmH2O). However, chemoreflex sensitivity was greater (2.38 ± 0.36 vs.1.88 ± 0.33 L/min/mmHg, p = 0.05) and carbon dioxide (CO2) values that demarcated the apneic threshold (morning: 38.24 ± 0.36 vs. afternoon/evening: 38.09 ± 0.88 mmHg) were closer to resting values in the morning compared to the other sessions (Δ CO2:1.85 ± 0.20 vs. 3.02 ± 0.19 mmHg, p = 0.001).Conclusions: Increased breathing instability in the morning may be a consequence of alterations in chemoreflex properties that vary across the 24 hr cycle.Grant Funding Source: Supported by VA Merit Award (2I01CX000125‐05A1) (JHM)
Ultrasonic diagnosis of hip dysplasia in rachitic pathology in infants (1180.14)
Authors: Karabekova R. , Gorobtsova A. , Shakeeva A. , Seidakhmetov M. 
Published: June 2021

Objective: to identify the signs of hip dysplasia in a large clinical material along with the symptoms of rickets (sweating, alopecia of the occipital region of the head, muscular hypotonia, irritability child).Materials: 935 children were observed at the CCH No 2 in Astana for 2010 with hip joint pathology, of whom up to 6 months, 56.6% after 6 months ‐ 32,6% to be conservative treatment and 10.8% children received surgical treatment.Results: Ultrasonography in 35.8% children 2‐3 months of age revealed a sharp flattening of the bone and bone bay window roof (angle d ranged between 34 ‐39), cartilaginous portion of the acetabulum has been shifted cranial ossification nucleus head femur was missing. At the age of 4‐5 months during treatment in the stirrups Pavlik appeared signs of the formation of the femoral head in the form of separate small “clumps” in 46.5% children in the remaining 36.5%, these terms are shifted to 6‐7 months of age (the angle d 48‐52). Only by 9‐10 months gradually underwent a process of mergers and the formation of a homogeneous core of ossification center of the femoral head (the angle d approaching 56‐58), cartilaginous portion of the roof of the acetabulum was relatively short. By the year 33% of patients the size of the hip bone formation were reduced, and only 67% of patients taking shape hip well‐formed, bone bay took a rectangular shape, cartilaginous part of the femoral head is completely covered).
Autologous cell sheet engineering: an animal product‐free approach (1180.23)
Authors: Wood Andrew , Sota Hiroyuki , Oliva‐Vilana Joan , Bardag‐Gorce Fawzia , Thropay Jacquelyn , Pan Derek , Niihara Yutaka 
Published: June 2021

While ex vivo expanded autologous cell sheet shows promise in replacing impaired corneal epitheliums; the engineering issues of using xenogeneic products during cell expansion remain to be addressed. To eliminate animal products, this study explores the use of two chemically defined media used sequentially for expansion and differentiation, where submerged and air‐exposure techniques are used respectively. The cells in the xenogeneic product‐free condition expanded well and reached confluency however only a single layer of basal cells was created. To resolve this issue, we found that the addition of 1 mM Ca2+ helps induce differentiation. However, air‐exposure could cause the apical surface to become dry and keratinized. To overcome this downside, a few drops of PBS as a moistener, were applied to the surface. The modified culture with this preventive technique successfully yielded non‐keratinized, multi‐stratified cell sheets that are morphologically similar to cell sheets engineered with the conventional method. These observations were confirmed by H&amp;E staining. Moreover, the sheet maintained the normal phenotypes; the basal cells stained positive for ΔN‐p63, Ki67 and PCNA, while the apical cells were stained for K3 and K13. The chemically defined non‐xenogeneic media showed promise in becoming a safe alternative for the epithelium production.Supported by Emmaus Life Sciences, Inc. and CellSeed, Inc.
TRPV1 channel activity triggered by hyperosmotic stimulation increases phosphorylated NOS activity in rat supraotic slices (1182.10)
Authors: Khachaturov Andranik , Tosonian Shawnt , Beitzel Christy , Curras‐Collazo Margarita 
Published: June 2021

Magnocellular neuroendocrine cells (MNCs) in the supraoptic (SON) and paraventricular nucleus (PVN) of the hypothalamus release vasopressin (VP) from axons and somata/dendrites in response to hyperosmotic stimulation. Transient receptor potential vanilloid 1 (TRPV1) channels mediate osmosensory transduction and axonal neurosecretion in SON MNCs. Our lab has shown that osmotic‐stimulated somatodendritic VP responses occur in a TRPV1‐ and NOS‐dependent manner. Since TRPV1 activation may result in NO production, our current study examined the interaction between TRPV1 and NO synthase (NOS) under hyperosmotic conditions. Acutely dissected SON slices were prepared from adult male Holtzman rats perfused with sucrose‐enriched aCSF under deep anesthesia. Slices were treated with hyperosmotic stimulation in the presence and absence of TRPV1 antagonist SB366791 (1.5 μM) and later post‐fixed. Using double‐label immunohistochemistry for phosphorylated stimulatory residue of neuronal NOS (p‐nNOS ser1412) and combined VP‐neurophysin (PS41) and oxytocin‐neurophysin (PS38) we found elevated p‐nNOS immunoreactivity in MNCs under hyperosmotic conditions but not always in the presence of SB366791, suggesting that increased NO signaling may occur downstream of TRPV1 channel activity. By analogy to other neuroendocrine systems p‐nNOS ser1412 may participate in neuropeptide secretion perhaps by coupling with NMDAr on MNCs. We also immunoprobed for downstream signaling partners of NOS and found expression of sGC (beta subunit), an enzyme that converts GTP to cGMP.We conclude that hyperosmotic stimulation activates TRPV1 channels that produce stimulatory phosphorylation of nNOS leading to somatodendritic release of VP from supraoptic MNCs.Grant Funding Source: Supported by American Physiological Society
Comparing cerebral blood flow velocity and cerebral blood flow measures between transcranial Doppler ultrasound and phase contrast magnetic resonance imaging during hypercapnia and hypocapnia (1183.2)
Authors: Coverdale Nicole , Gati Joe , Opalevych Oksana , Perrotta Amanda , Shoemaker J. Kevin 
Published: June 2021

To test the hypothesis that middle cerebral artery (MCA) diameter remains stable across physiologic stimuli, the cross‐sectional area (CSA) of the MCA was assessed using high‐field magnetic resonance imaging (MRI) (3T, T2 images) during hypercapnia (HC) and hypocapnia (HO). Estimates of cerebral blood flow velocity (CBV) collected with transcranial Doppler (TCD) ultrasound and phase contrast (PC) MRI were also compared with subsequent calculation of cerebrovascular reactivity (CVR). End‐tidal carbon dioxide (ETCO2) levels were manipulated through hyperventilation (30 breaths/min) and inhalation of 6% CO2 gas. The CSA increased from 5.5 ± 0.9 to 6.4 ± 1.2 mm2 (p<0.001; n=16) during HC and decreased from 5.7 ± 1.0 to 5.1 ± 0.8 mm2 (p<0.001; n=14) during HO. During HC CBV increased from 68 ± 9 to 85 ± 15 cm/s (p=0.003, n=7) measured with TCD and from 64 ± 10 to 85 ± 15 cm/s (p=0.002, n=7) measured with PC, while there was a decrease from 69 ± 8 to 55 ± 16 cm/s (p = 0.02, n=7) with TCD and from 61 ± 8 to 51 ± 8 cm/s (p = 0.02, n=7) during HO. Cerebrovascular reactivity during HC was 2.42 ± 3.98 cm/s/mmHg for TCD and 2.87 ± 1.63 cm/s/mmHg for PC (p = 0.70). Cerebrovascular reactivity during HO was ‐1.67 ± 1.37 cm/s/mmHg for TCD and ‐0.92 ± 1.17 cm/s/mmHg for PC (p = 0.11). Therefore, CSA of the MCA is not constant across this range of ETCO2. Further, TCD and PC provide similar estimates of absolute CBV and CVR during HO and HC.Grant Funding Source: Supported by the Canadian Institutes of Health Research
Alternateday fasting versus daily calorie restriction for weight loss and cardio‐protection (120.6)
Authors: Trepanowski John , Kroeger Cynthia , Klempel Monica , Calvo Yolian , Varady Krista 
Published: June 2021

Background: Alternate‐day fasting (ADF) has been shown to reduce body weight and improve coronary heart disease (CHD) risk parameters in overweight and obese humans. Whether ADF produces greater improvements in these parameters compared to traditional calorie restriction (CR) remains unknown.Methods: Overweight and obese subjects (n = 25) were randomized to 1 of 3 groups for 24 weeks: 1) ADF (feed day: 125% of energy needs, alternated with a fast day: 25% of energy needs; all meals provided); 2) CR (75% of energy needs every day; all meals provided); 3) Control (100% of energy needs every day; self‐selected diet).Results: ADF and CR resulted in similar (p > 0.05 relative to each other) reductions in body weight 8.3 ± 1.5% and 7.2 ± 1.2%, respectively; both p < 0.02 relative to control), fat mass (14.0 ± 2.2% and 15.2 ± 1.8%, respectively; both p < 0.02 relative to control), and visceral fat (0.51 ± 0.11 kg and 0.38 ± 0.12 kg, respectively; both p < 0.01 relative to control). Fat‐free mass did not change in any group (p > 0.05). Plasma lipids, glucose, insulin, C‐reactive protein, and systolic and diastolic blood pressure did not change in either intervention group relative to the control group (p > 0.05 for each) over the 24‐week trial.Conclusion: ADF and CR produce similar weight loss, and neither diet appears to modulate CHD risk. These findings are limited by small sample size, however, and warrant further investigation.