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1.
Ann Vasc Surg ; 38: 260-267, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27575303

RESUMO

BACKGROUND: Peripheral arterial disease (PAD) is an atherosclerotic vascular disease that affects over 200 million people worldwide. The hallmark of PAD is ischemic leg pain and this condition is also associated with an augmented blood pressure response to exercise, impaired vascular function, and high risk of myocardial infarction and cardiovascular mortality. In this study, we tested the hypothesis that coronary exercise hyperemia is impaired in PAD. METHODS: Twelve patients with PAD and no overt coronary disease (65 ± 2 years, 7 men) and 15 healthy control subjects (64 ± 2 years, 9 men) performed supine plantar flexion exercise (30 contractions/min, increasing workload). A subset of subjects (n = 7 PAD, n = 8 healthy) also performed isometric handgrip exercise (40% of maximum voluntary contraction to fatigue). Coronary blood velocity in the left anterior descending artery was measured by transthoracic Doppler echocardiography; blood pressure and heart rate were monitored continuously. RESULTS: Coronary blood velocity responses to 4 min of plantar flexion exercise (PAD: Δ2.4 ± 1.2, healthy: Δ6.0 ± 1.6 cm/sec, P = 0.039) and isometric handgrip exercise (PAD: Δ8.3 ± 4.2, healthy: Δ16.9 ± 3.6, P = 0.033) were attenuated in PAD patients. CONCLUSION: These data indicate that coronary exercise hyperemia is impaired in PAD, which may predispose these patients to myocardial ischemia.


Assuntos
Circulação Coronária , Vasos Coronários/fisiopatologia , Exercício Físico , Hiperemia/fisiopatologia , Extremidade Inferior/irrigação sanguínea , Doença Arterial Periférica/fisiopatologia , Extremidade Superior/irrigação sanguínea , Idoso , Velocidade do Fluxo Sanguíneo , Pressão Sanguínea , Estudos de Casos e Controles , Vasos Coronários/diagnóstico por imagem , Ecocardiografia Doppler , Teste de Esforço , Tolerância ao Exercício , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Fadiga Muscular , Posicionamento do Paciente , Doença Arterial Periférica/diagnóstico , Valor Preditivo dos Testes , Decúbito Dorsal
2.
Nutr J ; 15(1): 92, 2016 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-27769274

RESUMO

BACKGROUND: Exercise not only has a direct effect on energy balance through energy expenditure (EE), but also has an indirect effect through its impact on energy intake (EI). This study examined the effects of acute exercise on daily ad libitum EI in children at risk for becoming overweight due to family history. METHODS: Twenty healthy-weight children (ages 9-12 years, 12 male/8 female) with at least one overweight biological parent (body mass index ≥ 25 kg/m2) participated. Children reported to the laboratory for one baseline and two experimental visits (EX = exercise, SED = sedentary) each separated by 1 week in a randomized crossover design. Two hours into the EX day session, children exercised at 70 % estimated VO2max for 30 min on a cycle ergometer. Objective EI (kcal) was measured at a standard breakfast (~285 kcal) and ad libitum lunch, snack and dinner. Meals were identical on the EX and SED days. Activity-related EE (kcal) was estimated with accelerometers worn on the non-dominant wrist and ankle. Relative EI (kcal) was computed as the difference between Total EI and Activity-related EE for each testing day. Paired t-tests were performed to test differences in Total EI, Activity-related EE and Relative EI between the EX and SED days. RESULTS: Across all meals, Total EI was not statistically different between the EX and SED days (t = 1.8, p = 0.09). Activity-related EE was greater on the EX day compared to the SED day (t = 10.1, p < 0.001). By design, this difference was predominantly driven by activity during the morning (t = 20.4, p < 0.001). Because children consumed a similar number of kcal on each day, but had greater Activity-related EE on the EX day, Relative EI was lower (t = -5.15, p < 0.001) for the EX day (1636 ± 456 kcal) relative to the SED day (1862 ± 426 kcal). CONCLUSIONS: Imposed exercise was effective in reducing Relative EI compared to being sedentary. Morning exercise may help children at risk for becoming overweight to better regulate their energy balance within the course of a day.


Assuntos
Ingestão de Energia/fisiologia , Exercício Físico/fisiologia , Sobrepeso/fisiopatologia , Criança , Estudos Cross-Over , Dieta , Metabolismo Energético/fisiologia , Feminino , Humanos , Masculino , Refeições , Consumo de Oxigênio , Fatores de Risco , Fatores de Tempo
3.
Am J Physiol Heart Circ Physiol ; 309(3): H523-8, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-26055794

RESUMO

Prostanoids are produced during skeletal muscle contraction and subsequently stimulate muscle afferent nerves, thereby contributing to the exercise pressor reflex. Humans with peripheral arterial disease (PAD) have an augmented exercise pressor reflex, but the metabolite(s) responsible for this augmented response is not known. We tested the hypothesis that intravenous injection of ketorolac, which blocks the activity of cyclooxygenase, would attenuate the rise in mean arterial blood pressure (MAP) and heart rate (HR) evoked by plantar flexion exercise. Seven PAD patients underwent 4 min of single-leg dynamic plantar flexion (30 contractions/min) in the supine posture (workload: 0.5-2.0 kg). MAP and HR were measured on a beat-by-beat basis; changes from baseline in response to exercise were determined. Ketorolac did not affect MAP or HR at rest. During the first 20 s of exercise with the most symptomatic leg, ΔMAP was significantly attenuated by ketorolac (2 ± 2 mmHg) compared with control (8 ± 2 mmHg, P = 0.005), but ΔHR was similar (6 ± 2 vs. 5 ± 1 beats/min). Importantly, patients rated the exercise bout as "very light" to "fairly light," and average pain ratings were 1 of 10. Ketorolac had no effect on perceived exertion or pain ratings. Ketorolac also had no effect on MAP or HR in seven age- and sex-matched healthy subjects who performed a similar but longer plantar flexion protocol (workload: 0.5-7.0 kg). These data suggest that prostanoids contribute to the augmented exercise pressor reflex in patients with PAD.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase/farmacologia , Exercício Físico , Cetorolaco/farmacologia , Doença Arterial Periférica/fisiopatologia , Idoso , Estudos de Casos e Controles , Feminino , Pé/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/metabolismo
4.
J Chem Phys ; 143(4): 044308, 2015 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-26233130

RESUMO

Two-colour polarization labelling experiments have been used to explore the excitation spectrum of the rubidium dimer in the region 25,500-27,000 cm(-1), probing two mutually interacting states, identified from ab initio calculations as the 5(1)Σu(+) and 5(1)Πu states whose atomic dissociation products are Rb(5s) + Rb(5d). Treating the rather irregular progressions observed in the excitation spectra as transitions to single states with (numerous) local perturbations, we propose spectroscopic parameters and potential energy curves to describe the investigated levels. Observations cover more than 20 vibrational levels in the inner minima of both the 5(1)Πu and 5(1)Σu(+) states. Analysis was guided by ab initio calculations performed to describe the (1,3)Λg,u electronic states of Rb2 up to the Rb(5s) + Rb(5f) atomic asymptote. The theoretical potential energy curves are given in ASCII format in an electronic supplement to this paper.

5.
Am J Physiol Heart Circ Physiol ; 306(3): H309-16, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24322616

RESUMO

Clinical evidence indicates that obstructive sleep apnea is more common and more severe in men compared with women. Sex differences in the vasoconstrictor response to hypoxemia-induced sympathetic activation might contribute to this clinical observation. In the current laboratory study, we determined sex differences in the acute physiological responses to maximal voluntary end-expiratory apnea (MVEEA) during wakefulness in healthy young men and women (26 ± 1 yr) as well as healthy older men and women (64 ± 2 yr). Mean arterial pressure (MAP), heart rate (HR), brachial artery blood flow velocity (BBFV, Doppler ultrasound), and cutaneous vascular conductance (CVC, laser Doppler flowmetry) were measured, and changes in physiological parameters from baseline were compared between groups. The breath-hold duration and oxygen-saturation nadir were similar between groups. In response to MVEEA, young women had significantly less forearm vasoconstriction compared with young men (ΔBBFV: 2 ± 7 vs. -25 ± 6% and ΔCVC: -5 ± 4 vs. -31 ± 4%), whereas ΔMAP (12 ± 2 vs. 16 ± 3 mmHg) and ΔHR (4 ± 2 vs. 6 ± 3 bpm) were comparable between groups. The attenuated forearm vasoconstriction in young women was not observed in postmenopausal women (ΔBBFV -21 ± 5%). We concluded that young women have blunted forearm vasoconstriction in response to MVEEA compared with young men, and this effect is not evident in older postmenopausal women. These data suggest that female sex hormones dampen neurogenic vasoconstriction in response to apnea-induced hypoxemia.


Assuntos
Apneia/fisiopatologia , Braço/fisiologia , Pressão Sanguínea/fisiologia , Vasoconstrição/fisiologia , Adulto , Fatores Etários , Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Braquial/fisiologia , Estudos de Casos e Controles , Feminino , Frequência Cardíaca/fisiologia , Homeostase/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fluxo Sanguíneo Regional/fisiologia , Fatores Sexuais , Resistência Vascular/fisiologia
6.
Am J Physiol Heart Circ Physiol ; 307(10): H1497-503, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25239806

RESUMO

Patients with coronary artery disease have attenuated coronary vasodilator responses to physiological stress, which is partially attributed to a ß-adrenergic receptor (ß-AR)-mediated mechanisms. Whether ß-ARs contribute to impaired coronary vasodilation seen with healthy aging is unknown. The purpose of this study was to investigate the role of ß-ARs in coronary exercise hyperemia in healthy humans. Six young men (26 ± 1 yr) and seven older men (67 ± 4 yr) performed isometric handgrip exercise at 30% maximal voluntary contraction for 2 min after receiving intravenous propranolol, a ß-AR antagonist, and no treatment. Isoproterenol, a ß-AR agonist, was infused to confirm the ß-AR blockade. Blood pressure and heart rate were monitored continuously, and coronary blood flow velocity (CBV, left anterior descending artery) was measured by transthoracic Doppler echocardiography. Older men had an attenuated ΔCBV to isometric exercise (3.8 ± 1.3 vs. 9.7 ± 2.1 cm/s, P = 0.02) compared with young men. Propranolol decreased the ΔCBV at peak handgrip exercise in young men (9.7 ± 2.1 vs. 2.7 ± 0.9 cm/s, P = 0.008). However, propranolol had no effect on ΔCBV in older men (3.8 ± 1.3 vs. 4.2 ± 1.9 cm/s, P = 0.9). Older men also had attenuated coronary hyperemia to low-dose isoproterenol. These data indicate that ß-AR control of coronary blood flow is impaired in healthy older men.


Assuntos
Antagonistas Adrenérgicos beta/administração & dosagem , Envelhecimento , Vasos Coronários/efeitos dos fármacos , Exercício Físico , Hiperemia/fisiopatologia , Propranolol/administração & dosagem , Vasodilatação/efeitos dos fármacos , Agonistas Adrenérgicos beta/administração & dosagem , Adulto , Fatores Etários , Idoso , Vasos Coronários/fisiopatologia , Estudos Cross-Over , Ecocardiografia Doppler , Força da Mão , Voluntários Saudáveis , Humanos , Infusões Intravenosas , Contração Isométrica , Isoproterenol/administração & dosagem , Masculino , Pessoa de Meia-Idade
7.
Am J Physiol Regul Integr Comp Physiol ; 307(7): R888-92, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25031228

RESUMO

Blunted dipping of nocturnal systolic arterial pressure (SAP) and heart rate (HR) are independent risk factors for hypertension and all-cause mortality. While several epidemiological studies report a significant association between short sleep duration and hypertension, associations between sleep efficiency and the nocturnal drop of SAP remain controversial. Moreover, relations between sleep efficiency and HR diurnal patterns have been overlooked. We hypothesized that low sleep efficiency (<85%) would be associated with blunted nocturnal SAP and HR dipping. Twenty-two normotensive subjects (13 men, 9 women; age: 18-28 yr) wore an actigraphy watch for 7 days and nights, and an ambulatory blood pressure monitor for 24 h on a nonactigraph night. There were no differences in age, sex, body mass index, mean sleep time, number of awakenings, or 24-h blood pressure between the low (n = 12) and high (n = 10) sleep efficiency groups. However, the low sleep efficiency subjects demonstrated a blunted dip of nocturnal SAP (10 ± 1% vs. 14 ± 1%, P = 0.04) and HR (12 ± 3% vs. 21 ± 3%, P = 0.03) compared with the high sleep efficiency group. The low sleep efficiency group also demonstrated a higher mean nocturnal HR (63 ± 2 vs. 55 ± 2 beats/min; P = 0.02). These findings support growing evidence that sleep efficiency, independent of total sleep time, may be an important cardiovascular risk factor.


Assuntos
Pressão Sanguínea/fisiologia , Doenças Cardiovasculares/etiologia , Hipertensão/etiologia , Sono/fisiologia , Adolescente , Adulto , Monitorização Ambulatorial da Pressão Arterial/métodos , Ritmo Circadiano/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Hemodinâmica/fisiologia , Humanos , Masculino , Fatores de Risco , Adulto Jovem
8.
Clin Sci (Lond) ; 126(4): 289-96, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23978222

RESUMO

POTS (postural tachycardia syndrome) is a chronic form of OI (orthostatic intolerance). Neuropathic POTS is characterized by decreased adrenergic vasoconstriction, whereas hyperadrenergic POTS exhibits increased adrenergic vasoconstriction. We hypothesized that midodrine, an α1-adrenergic receptor agonist, would increase CVR (calf vascular resistance), decrease C(v) (calf venous capacitance) and decrease orthostatic tachycardia in neuropathic POTS, but not alter haemodynamics in hyperadrenergic POTS. A total of 20 POTS patients (12 neuropathic and eight hyperadrenergic), ages 12-20 years, participated in this randomized placebo-controlled double-blind cross-over study. Of these subjects, 15 were female. POTS subjects received 2 weeks of treatment with midodrine or placebo, with increased dosing from 2.5 to 10 mg three times daily. Following a 7-day drug-washout period, subjects received the cross-over treatment. HR (heart rate), MAP (mean arterial pressure), Q(calf) (calf blood flow) and CVR were measured supine and during 35° HUT (head-up tilt). C(v) was measured supine. In neuropathic POTS, midodrine decreased supine HR, Q(calf) and C(v), while increasing MAP and CVR compared with placebo. During HUT, in neuropathic POTS, midodrine decreased HR, Q(calf) and C(v), while increasing MAP and CVR. In hyperadrenergic POTS, placebo and midodrine both decreased upright HR and increased supine CVR. Placebo also increased supine C(v), compared with midodrine in hyperadrenergic POTS. Therefore midodrine improved postural tachycardia in neuropathic POTS by increasing CVR and decreasing Q(calf) and C(v), whereas these effects were not seen in hyperadrenergic POTS patients who experienced a placebo effect. This suggests that midodrine is probably an effective treatment for neuropathic POTS, but not for hyperadrenergic POTS.


Assuntos
Midodrina/uso terapêutico , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Síndrome da Taquicardia Postural Ortostática/tratamento farmacológico , Vasoconstrição/efeitos dos fármacos , Adolescente , Adulto , Pressão Sanguínea/fisiologia , Criança , Estudos Cross-Over , Método Duplo-Cego , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Midodrina/administração & dosagem , Efeito Placebo , Taquicardia/tratamento farmacológico , Resultado do Tratamento , Adulto Jovem
9.
Clin Auton Res ; 23(6): 305-11, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23999934

RESUMO

PURPOSE: Adolescents with postural tachycardia syndrome (POTS) often experience ill-defined cognitive impairment referred to by patients as "brain fog." The objective of this study was to evaluate the symptom of brain fog as a means of gaining further insight into its etiology and potential palliative interventions. METHODS: Eligible subjects who reported having been diagnosed with POTS were recruited from social media web sites. Subjects were asked to complete a 38-item questionnaire designed for this study, and the Wood mental fatigue inventory (WMFI). RESULTS: Responses were received from 138 subjects with POTS (88 % female), ranging in age from 14 to 29 years; 132 subjects reported brain fog. WMFI scores correlated with brain fog frequency and severity (P < 0.001). The top ranked descriptors of brain fog were "forgetful," "cloudy," and "difficulty focusing, thinking and communicating." The most frequently reported brain fog triggers were fatigue (91 %), lack of sleep (90 %), prolonged standing (87 %), dehydration (86 %), and feeling faint (85 %). Although aggravated by upright posture, brain fog was reported to persist after assuming a recumbent posture. The most frequently reported interventions for the treatment of brain fog were intravenous saline (77 %), stimulant medications (67 %), salt tablets (54 %), intra-muscular vitamin B-12 injections (48 %), and midodrine (45 %). CONCLUSIONS: Descriptors for "brain fog" are most consistent with it being a cognitive complaint. Factors other than upright posture may play a role in the persistence of this symptom. Subjects reported a number of therapeutic interventions for brain fog not typically used in the treatment of POTS that may warrant further investigation.


Assuntos
Transtornos Cognitivos/etiologia , Síndrome da Taquicardia Postural Ortostática/complicações , Adolescente , Adulto , Feminino , Humanos , Masculino , Inquéritos e Questionários , Adulto Jovem
10.
Data Brief ; 42: 108038, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35341037

RESUMO

Transmittance and absorbance data in the form of a spectral atlas have been obtained from Fourier transform spectra recorded on a commercial (Bomem DA3) instrument, operated with an external white light source injected through the instrument's `emission' port. The sample was a sealed, evacuated cell containing a small quantity of 130Te. This cell was placed in a ceramic furnace maintained close to 620 °C, with tellurium vapor pressures 8-11 Torr. The data are intended as an aid to spectral calibration in the blue-green to violet region. The data relate to work published in J. Mol. Spectrosc. 384 111,589 (2022).

11.
J Chem Phys ; 135(11): 114302, 2011 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-21950857

RESUMO

Using high-resolution Fourier transform emission techniques, we have resolved rotational structure in the D0(u)(+)((3)P(2)) → X0(g)(+) emission following collisional transfer from the E0(g)(+)((3)P(2)) state in I(2). The P:R branch ratios in the E0(g)(+)((3)P(2)) → D0(u)(+)((3)P(2)) transfer are found to vary enormously with v(E) and v(D). We show that the observed intensities are all consistent with the transfer being dominated by long-range, near-resonant collisions with residual H(2)O. Unequal P:R branch ratios in the E0(g)(+)((3)P(2)) → A1(u) emission have been shown to result from mixing of the E0(g)(+)((3)P(2)) and ß1(g)((3)P(2)) states via Ω-uncoupling.

12.
J Phys Chem A ; 113(47): 13159-66, 2009 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-19603775

RESUMO

A metal sputtering source suitable for laboratory production of metal hydrides is described. Sputtering from pure nickel or iron in an Ar/H(2) discharge is analyzed at low resolution. High resolution laser excitation and dispersed fluorescence spectra of NiH have also been recorded. The source has been designed to operate with a ferromagnetic circuit for Zeeman spectroscopy. Signals from the source are strong enough to record dispersed fluorescence from NiH by Fourier transform interferometry in magnetic fields up to 1 T. We establish that FeH can also be formed in this source.


Assuntos
Hidrogênio/química , Ferro/química , Níquel/química , Temperatura , Argônio/química
13.
J Chem Phys ; 131(20): 204309, 2009 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-19947682

RESUMO

Extensions of the recently introduced "Morse/long-range" (MLR) potential function form allow a straightforward treatment of a molecular state for which the inverse-power long-range potential changes character with internuclear separation. Use of this function in a direct-potential-fit analysis of a combination of new fluorescence data for (7,7)Li(2), (6,6)Li(2), and (6,7)Li(2) with previously reported data for the A((1)Sigma(u) (+)) and X((1)Sigma(g) (+)) states yields accurate, fully analytic potentials for both states, together with the analytic "adiabatic" Born-Oppenheimer breakdown radial correction functions which are responsible for the difference between the interaction potentials and well depths for the different isotopologues. This analysis yields accurate well depths of D(e)=8516.709(+/-0.004) and 8516.774(+/-0.004) cm(-1) and scattering lengths of 18.11(+/-0.05) and 23.84(+/-0.05) A for the ground-states of (7,7)Li(2) and (6,6)Li(2), respectively, as well as improved atomic radiative lifetimes of tau(2p)=27.1018(+/-0.0014) ns for (7)Li(2p) and 27.1024(+/-0.0014) ns for (6)Li(2p).

14.
Eplasty ; 17: e15, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28458765

RESUMO

Introduction: Deep sternal wound infection following major cardiac surgery is a deleterious complication with sequelae that can be life threatening. The use of vacuum-assisted closure therapy in management of sternal wounds with resultant right ventricular rupture has been documented in the cardiothoracic and to a lesser extent in the reconstructive literature. Methods/Case Report: We present a case of a 67-year-old male patient who suffered from right ventricular perforation from a floating rib following debridement of a deep sternal wound infection and placement of a vacuum-assisted closure device. Results: Despite meticulous debridement and ensuring the release of all retrosternal adhesions, massive bleeding was encountered shortly after application of the vacuum-assisted closure device. Fortunately, quick identification of the complication and the application of direct manual pressure allowed for swift return to the operating room for repair of the defect. The patient secondarily underwent definitive closure of the mediastinal wound with an omental flap and bilateral pectoral advancement flaps. Discussion: Following the conclusion of this article, the reconstructive surgeon should be able to (1) identify patients at risk for ventricular perforation, (2) exhaust all means intraoperatively to prevent cardiac perforation when using vacuum-assisted closure therapy, (3) comprehend the physiology associated with vacuum-assisted closure use in this patient population, (4) have protocols in place for the management of patients with deep sternal wound infection with vacuum-assisted closure therapy postoperatively, and (5) understand basic tenets of ventricular rupture treatment should this occur to ensure prompt repair and survival.

15.
J Appl Physiol (1985) ; 122(3): 511-519, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28035016

RESUMO

Despite its widespread clinical use, the ß1-adrenergic receptor antagonist esmolol hydrochloride is not commonly used in human physiology research, and the effective dose of esmolol (compared with the nonselective ß-blocker propranolol) is unclear. In four separate studies we used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate (HR)-lowering effect of esmolol compared with propranolol and saline in healthy humans. In cohort 1, both esmolol (ΔHR 57 ± 6 beats/min) and propranolol (ΔHR 56 ± 7 beats/min) attenuated exercise tachycardia compared with saline (ΔHR 88 ± 17 beats/min). In cohort 2, we found that the HR response to exercise was similar at 5 min (ΔHR 57 ± 9 beats/min) and 60 min (ΔHR 55 ± 9 beats/min) after initiation of the esmolol maintenance infusion. In cohort 3, we confirmed that the HR-lowering effect of esmolol disappeared 45 min after termination of the maintenance infusion. In cohort 4, changes in femoral blood flow and hematological parameters in response to epinephrine infusion were not different between esmolol and saline infusion, indicating that our esmolol infusion paradigm does not block ß2-receptors. Collectively, our data indicate that infusion of ~160 mg of esmolol (range 110-200 mg in the 5 min before exercise) acutely and selectively blocks ß1-receptors in healthy humans. Additionally, ß1-receptors remain blocked 60 min later if a maintenance infusion of ~0.2 mg·kg total body mass-1·min-1 continues. The current data lay the foundation for future studies to evaluate ß1- vs. ß2-receptor control of the circulation in humans.NEW & NOTEWORTHY We used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate-lowering effect of esmolol compared with propranolol and saline in healthy humans. Collectively, our data indicate that infusion of ~160 mg of esmolol (range 110-200 mg in the 5 min before exercise) acutely and selectively blocks ß1-adrenergic receptors. These infusion parameters can be used in future experiments to evaluate ß1- vs. ß2-receptor control of the circulation in humans.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Propanolaminas/farmacologia , Propranolol/farmacologia , Adulto , Antiarrítmicos/administração & dosagem , Antiarrítmicos/farmacologia , Teste de Esforço , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Propanolaminas/administração & dosagem , Propranolol/administração & dosagem , Valores de Referência , Resultado do Tratamento
16.
Physiol Rep ; 4(20)2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27798357

RESUMO

Blood-oxygen-level-dependent magnetic resonance imaging (BOLD MRI) has the potential to quantify skeletal muscle oxygenation with high temporal and high spatial resolution. The purpose of this study was to characterize skeletal muscle BOLD responses during steady-state plantar flexion exercise (i.e., during the brief rest periods between muscle contraction). We used three different imaging modalities (ultrasound of the popliteal artery, BOLD MRI, and near-infrared spectroscopy [NIRS]) and two different exercise intensities (2 and 6 kg). Six healthy men underwent three separate protocols of dynamic plantar flexion exercise on separate days and acute physiological responses were measured. Ultrasound studies showed the percent change in popliteal velocity from baseline to the end of exercise was 151 ± 24% during 2 kg and 589 ± 145% during 6 kg. MRI studies showed an abrupt decrease in BOLD signal intensity at the onset of 2 kg exercise, indicating deoxygenation. The BOLD signal was further reduced during 6 kg exercise (compared to 2 kg) at 1 min (-4.3 ± 0.7 vs. -1.2 ± 0.4%, P < 0.001). Similarly, the change in the NIRS muscle oxygen saturation in the medial gastrocnemius was -11 ± 4% at 2 kg and -38 ± 11% with 6 kg (P = 0.041). In conclusion, we demonstrate that BOLD signal intensity decreases during plantar flexion and this effect is augmented at higher exercise workloads.


Assuntos
Imageamento por Ressonância Magnética/métodos , Contração Muscular/fisiologia , Músculo Esquelético/metabolismo , Consumo de Oxigênio/fisiologia , Artéria Poplítea/diagnóstico por imagem , Adulto , Exercício Físico/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Ultrassonografia/métodos , Adulto Jovem
18.
J Chem Phys ; 127(2): 024309, 2007 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-17640130

RESUMO

The spin-orbit splitting of CuCl(2) in its ground X(2)Pi(g) state remains an unknown or, at best, poorly defined quantity. The electronic spectrum of CuCl(2) has been studied by Fourier transform resolved, laser-induced fluorescence between 602 and 587 nm, in an attempt to identify transitions to the upper spin component of the ground state. In order to provide a well-defined excitation process, the sample was cooled to rotational temperatures of about 10 K in a free-jet expansion. Observations from just two rotationally perturbed levels in the upper electronic state, one for (63)Cu(35)Cl(2) and the other for (65)Cu(35)Cl(37)Cl, have revealed an additional feature about 482 cm(-1) above the (2)Pi(3/2) state. The effective rotational constants associated with these levels (0.066 20 cm(-1) for (63)Cu(35)Cl(2)) are significantly larger than those for the ground (2)Pi(3/2) state (0.058 13 cm(-1)). Analysis of this feature as the (2)Pi(1/2) component leads to a value of -482.9 cm(-1) for the spin-orbit coupling constant A and of -0.0846 cm(-1) for the lambda-doubling parameter (p+2q) for (63)Cu(35)Cl(2). Several other previously unobserved levels are also identified within 2000 cm(-1) of the ground state. Many of these also have anomalously large rotational constants.

19.
Trop Med Int Health ; 10(1): 3-10, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15655008

RESUMO

OBJECTIVE: Neurological deficits are reported in children after cerebral malaria (CM) but little is known about the prevalence and characteristics of persisting neurocognitive consequences. The prevalence of developmental impairments following other complications of falciparum malaria, such as multiple, prolonged or focal seizures, is not known. Thus, our objective was to investigate the long-term developmental outcome of CM and malaria with complicated seizures (M/S). METHODS: We followed up a cohort of children previously exposed to CM or M/S and children unexposed to either condition. All children between 6 and 9 years of age, exposed to CM, and an equal number of children exposed to M/S were identified from databases of hospital admissions from 1991 to 1998. The unexposed group was randomly selected from a census database. The children's performance was measured using assessments of cognition, motor, speech and language, hearing and vision. A parental questionnaire was used to identify children with epilepsy. RESULTS: CM group scores were significantly lower than unexposed group scores on the assessments of higher level language (adjusted mean difference -1.63, 95% CI: -2.99 to -0.27), vocabulary (-0.02, 95% CI: -0.04 to -0.01), pragmatics (OR 2.81, 95% CI: 1.04-7.6) and non-verbal functioning (-0.33, 95% CI: -0.61 to -0.06). The areas of significantly reduced functioning for the M/S group were concentrated on phonology (OR 2.74, 95% CI: 1.26-5.95), pragmatics (OR 3.23, 95% CI: 1.2-8.71) and behaviour (OR 1.8, 95% CI: 1.0-3.23). The performance of the active epilepsy group was significantly poorer than that of the group without epilepsy on the tests of comprehension, syntax, pragmatics, word finding, memory, attention, behaviour and motor skills. CONCLUSIONS: CM and M/S are associated with developmental impairments. If these impairments persist, this may have implications for least 250,000 children in Sub-Saharan Africa each year. Active epilepsy significantly increases the risk of cognitive and behavioural problems in children with a history of severe malaria.


Assuntos
Deficiências do Desenvolvimento/etiologia , Malária Falciparum/psicologia , Criança , Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/etiologia , Deficiências do Desenvolvimento/epidemiologia , Epilepsia/psicologia , Feminino , Seguimentos , Humanos , Quênia/epidemiologia , Transtornos do Desenvolvimento da Linguagem/epidemiologia , Transtornos do Desenvolvimento da Linguagem/etiologia , Malária Cerebral/psicologia , Masculino , Prevalência , Convulsões/parasitologia , Convulsões/psicologia , Distúrbios da Fala/epidemiologia , Distúrbios da Fala/etiologia
20.
Epilepsia ; 45(8): 978-81, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15270766

RESUMO

PURPOSE: Multiple, prolonged, generalized, or focal seizures are common in children with severe malaria, with or without coma. In other contexts, such seizures have been associated with the development of epilepsy. The relation between falciparum malaria and epilepsy is undetermined; thus we measured the prevalence and characteristics of epilepsy in children with a history of severe malaria. METHODS: We took a detailed epilepsy history from the parents of 487 children (aged 6-9 years) to compare the prevalence of epilepsy between three exposure groups: children with a history of cerebral malaria (CM), malaria and complicated seizures (M/S), or those unexposed to either complication. Each child had an EEG and was classified as having active, inactive, or no epilepsy. RESULTS: An increased prevalence of epilepsy was seen in children previously admitted with CM [9.2%; OR, 4.4; 95% confidence interval (CI), 1.4-13.7] or M/S (11.5%; OR, 6.1; 95% CI, 2.0-18.3) compared with the unexposed group (2.2%). The most commonly reported seizure types were tonic-clonic (42%), focal becoming secondarily generalized (16%), and both (21%). Twenty-six percent of the active epilepsy group initially had EEG abnormalities. CONCLUSIONS: These results suggest that children exposed to CM or M/S have an increased propensity for epilepsy relative to children unexposed to these complications. The prevalence of epilepsy associated with CM is similar to that reported after other severe encephalopathies. The prevalence associated with M/S is more than twice that reported after complicated febrile seizures.


Assuntos
Epilepsia/epidemiologia , Malária Falciparum/epidemiologia , Criança , Comorbidade , Eletroencefalografia/estatística & dados numéricos , Epilepsia/diagnóstico , Epilepsia Tônico-Clônica/diagnóstico , Epilepsia Tônico-Clônica/epidemiologia , Feminino , Humanos , Quênia/epidemiologia , Malária Cerebral/diagnóstico , Malária Cerebral/epidemiologia , Malária Falciparum/diagnóstico , Masculino , Prevalência , Convulsões/diagnóstico , Convulsões/epidemiologia , Convulsões Febris/diagnóstico , Convulsões Febris/epidemiologia , Índice de Gravidade de Doença
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