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1.
Clin Infect Dis ; 71(9): 2459-2468, 2020 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-32358954

RESUMO

BACKGROUND: To explore and describe the current literature surrounding bacterial/fungal coinfection in patients with coronavirus infection. METHODS: MEDLINE, EMBASE, and Web of Science were searched using broad-based search criteria relating to coronavirus and bacterial coinfection. Articles presenting clinical data for patients with coronavirus infection (defined as SARS-1, MERS, SARS-CoV-2, and other coronavirus) and bacterial/fungal coinfection reported in English, Mandarin, or Italian were included. Data describing bacterial/fungal coinfections, treatments, and outcomes were extracted. Secondary analysis of studies reporting antimicrobial prescribing in SARS-CoV-2 even in absence of coinfection was performed. RESULTS: 1007 abstracts were identified. Eighteen full texts reporting bacterial/fungal coinfection were included. Most studies did not identify or report bacterial/fungal coinfection (85/140; 61%). Nine of 18 (50%) studies reported on COVID-19, 5/18 (28%) on SARS-1, 1/18 (6%) on MERS, and 3/18 (17%) on other coronaviruses. For COVID-19, 62/806 (8%) patients were reported as experiencing bacterial/fungal coinfection during hospital admission. Secondary analysis demonstrated wide use of broad-spectrum antibacterials, despite a paucity of evidence for bacterial coinfection. On secondary analysis, 1450/2010 (72%) of patients reported received antimicrobial therapy. No antimicrobial stewardship interventions were described. For non-COVID-19 cases, bacterial/fungal coinfection was reported in 89/815 (11%) of patients. Broad-spectrum antibiotic use was reported. CONCLUSIONS: Despite frequent prescription of broad-spectrum empirical antimicrobials in patients with coronavirus-associated respiratory infections, there is a paucity of data to support the association with respiratory bacterial/fungal coinfection. Generation of prospective evidence to support development of antimicrobial policy and appropriate stewardship interventions specific for the COVID-19 pandemic is urgently required.


Assuntos
Anti-Infecciosos/uso terapêutico , Tratamento Farmacológico da COVID-19 , Coinfecção/tratamento farmacológico , SARS-CoV-2/efeitos dos fármacos , Gestão de Antimicrobianos , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , COVID-19/epidemiologia , COVID-19/microbiologia , Coinfecção/epidemiologia , Coinfecção/microbiologia , Resistência Microbiana a Medicamentos , Humanos , Micoses/tratamento farmacológico , Micoses/epidemiologia , Micoses/microbiologia
2.
J Appl Physiol (1985) ; 127(5): 1478-1490, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31343948

RESUMO

Raynaud's phenomenon (RP) is characterized by recurrent transient peripheral vasospasm and lower nitric oxide (NO) bioavailability in the cold. We investigated the effect of nitrate-rich beetroot juice (BJ) supplementation on 1) NO-mediated vasodilation, 2) cutaneous vascular conductance (CVC) and skin temperature (Tsk) following local cooling, and 3) systemic anti-inflammatory status. Following baseline testing, 23 individuals with RP attended four times, in a double-blind, randomized crossover design, following acute and chronic (14 days) BJ and nitrate-depleted beetroot juice (NDBJ) supplementation. Peripheral Tsk and CVC were measured during and after mild hand and foot cooling, and during transdermal delivery of acetylcholine and sodium nitroprusside. Markers of anti-inflammatory status were also measured. Plasma nitrite concentration ([nitrite]) was increased in the BJ conditions (P < 0.001). Compared with the baseline visit, thumb CVC was greater following chronic-BJ (Δ2.0 flux/mmHg, P = 0.02) and chronic-NDBJ (Δ1.45 flux/mmHg, P = 0.01) supplementation; however, no changes in Tsk were observed (P > 0.05). Plasma [interleukin-10] was greater, pan endothelin and systolic and diastolic blood pressure (BP) were reduced, and forearm endothelial function was improved, by both BJ and NDBJ supplementation (P < 0.05). Acute and chronic BJ and NDBJ supplementation improved anti-inflammatory status, endothelial function and blood pressure (BP). CVC following cooling increased post chronic-BJ and chronic-NDBJ supplementation, but no effect on Tsk was observed. The key findings are that beetroot supplementation improves thumb blood flow, improves endothelial function and anti-inflammatory status, and reduces BP in people with Raynaud's.NEW & NOTEWORTHY This is the first study to examine the effect of dietary nitrate supplementation in individuals with Raynaud's phenomenon. The principal novel findings from this study were that both beetroot juice and nitrate-depleted beetroot juice 1) increased blood flow in the thumb following a cold challenge; 2) enhanced endothelium-dependent and -independent vasodilation in the forearm; 3) reduced systolic and diastolic blood pressure, and pan-endothelin concentration; and 4) improved inflammatory status in comparison to baseline.


Assuntos
Anti-Inflamatórios/administração & dosagem , Beta vulgaris , Velocidade do Fluxo Sanguíneo/fisiologia , Endotélio Vascular/fisiologia , Sucos de Frutas e Vegetais , Doença de Raynaud/dietoterapia , Fluxo Sanguíneo Regional/fisiologia , Idoso , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Endotélio Vascular/efeitos dos fármacos , Feminino , Humanos , Masculino , Microvasos/efeitos dos fármacos , Microvasos/fisiologia , Pessoa de Meia-Idade , Doença de Raynaud/fisiopatologia , Fluxo Sanguíneo Regional/efeitos dos fármacos
3.
Nitric Oxide ; 70: 76-85, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28941934

RESUMO

Individuals with cold sensitivity have low peripheral skin blood flow and skin temperature possibly due to reduced nitric oxide (NO•) bioavailability. Beetroot has a high concentration of inorganic nitrate and may increase NO-mediated vasodilation. Using a placebo-controlled, double blind, randomised, crossover design, this study tested the hypotheses that acute beetroot supplementation would increase the rate of cutaneous rewarming following a local cold challenge and augment endothelium-dependent vasodilation in cold sensitive individuals. Thirteen cold sensitive participants completed foot and hand cooling (separately, in 15 °C water for 2 min) with spontaneous rewarming in 30 °C air whilst skin temperature and cutaneous vascular conductance (CVC) were measured (Baseline). On two further separate visits, participants consumed 140 ml of either concentrated beetroot juice (nitrate supplementation) or nitrate-depleted beetroot juice (Placebo) 90 min before resting seated blood pressure was measured. Endothelial function was assessed by measuring CVC at the forearm, finger and foot during iontophoresis of 1% w/v acetylcholine followed by foot and hand cooling as for Baseline. Plasma nitrite concentrations significantly increased in nitrate supplementation compared to Placebo and Baseline (502 ± 246 nmol L-1; 73 ± 45 nmol L-1; 74 ± 49 nmol L-1 respectively; n = 11; P < 0.001). Resting blood pressure and the response to foot and hand cooling did not differ between conditions (all P > 0.05). Nitrate supplementation did not alter endothelial function in the forearm, finger or foot (all P > 0.05) compared to Placebo. Despite a physiologically meaningful rise in plasma nitrite concentrations, acute nitrate supplementation does not alter extremity rewarming, endothelial function or blood pressure in individuals with cold sensitivity.


Assuntos
Temperatura Baixa/efeitos adversos , Suplementos Nutricionais , Endotélio Vascular/efeitos dos fármacos , Nitratos/farmacologia , Acetilcolina/administração & dosagem , Adulto , Beta vulgaris , Pressão Sanguínea/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Endotélio Vascular/fisiologia , Feminino , Dedos/irrigação sanguínea , Pé/irrigação sanguínea , Antebraço/irrigação sanguínea , Sucos de Frutas e Vegetais , Humanos , Masculino , Pessoa de Meia-Idade , Nitratos/administração & dosagem , Nitratos/sangue , Nitritos/sangue , Fluxo Sanguíneo Regional , Reaquecimento
6.
Free Radic Biol Med ; 86: 200-8, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25998421

RESUMO

Dietary nitrate supplementation has been shown to reduce the oxygen (O2) cost of exercise and enhance exercise tolerance in healthy individuals. This study assessed whether similar effects could be observed in individuals with type 2 diabetes (T2DM). In a randomized, double-blind, placebo-controlled crossover study, 48 participants with T2DM supplemented their diet for 4 days with either nitrate-rich beetroot juice (70ml/day, 6.43mmol nitrate/day) or nitrate-depleted beetroot juice as placebo (70ml/day, 0.07mmol nitrate/day). After each intervention period, resting plasma nitrate and nitrite concentrations were measured subsequent to participants completing moderate-paced walking. Pulmonary gas exchange was measured to assess the O2 cost of walking. After a rest period, participants performed the 6-min walk test (6MWT). Relative to placebo, beetroot juice resulted in a significant increase in plasma nitrate (placebo, 57±66 vs beetroot, 319±110µM; P < 0.001) and plasma nitrite concentration (placebo, 680±256 vs beetroot, 1065±607nM; P < 0.001). There were no differences between placebo juice and beetroot juice for the O2 cost of walking (946±221 vs 939±223ml/min, respectively; P = 0.59) and distance covered in the 6MWT (550±83 vs 554±90m, respectively; P = 0.17). Nitrate supplementation did not affect the O2 cost of moderate-paced walking or improve performance in the 6MWT. These findings indicate that dietary nitrate supplementation does not modulate the response to exercise in individuals with T2DM.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Nitratos/administração & dosagem , Idoso , Antioxidantes/análise , Beta vulgaris/química , Terapia Combinada , Estudos Cross-Over , Diabetes Mellitus Tipo 2/metabolismo , Suplementos Nutricionais , Método Duplo-Cego , Terapia por Exercício , Feminino , Sucos de Frutas e Vegetais/análise , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Resultado do Tratamento , Caminhada
7.
Nitric Oxide ; 48: 31-7, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-25596150

RESUMO

BACKGROUND: Chronic obstructive pulmonary disease (COPD) results in exercise intolerance. Dietary nitrate supplementation has been shown to lower blood pressure (BP), reduce the oxygen cost of exercise, and enhance exercise tolerance in healthy volunteers. This study assessed the effects of dietary nitrate on the oxygen cost of cycling, walking performance and BP in individuals with mild-moderate COPD. METHODS: Thirteen patients with mild-moderate COPD were recruited. Participants consumed 70 ml of either nitrate-rich (6.77 mmol nitrate; beetroot juice) or nitrate-depleted beetroot juice (0.002 mmol nitrate; placebo) twice a day for 2.5 days, with the final supplement ~3 hours before testing. BP was measured before completing two bouts of moderate-intensity cycling, where pulmonary gas exchange was measured throughout. The six-minute walk test (6 MWT) was completed 30 minutes subsequent to the second cycling bout. RESULTS: Plasma nitrate concentration was significantly elevated following beetroot juice vs. placebo (placebo; 48 ± 86 vs. beetroot juice; 215 ± 84 µM, P = 0.002). No significant differences were observed between placebo vs. beetroot juice for oxygen cost of exercise (933 ± 323 vs. 939 ± 302 ml: min(-1); P = 0.88), distance covered in the 6 MWT (456 ± 86 vs. 449 ± 79 m; P = 0.37), systolic BP (123 ± 14 vs. 123 ± 14 mmHg; P = 0.91), or diastolic BP (77 ± 9 vs. 79 ± 9 mmHg; P = 0.27). CONCLUSION: Despite a large rise in plasma nitrate concentration, two days of nitrate supplementation did not reduce the oxygen cost of moderate intensity cycling, increase distance covered in the 6 MWT, or lower BP.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Exercício Físico/fisiologia , Nitratos/farmacologia , Doença Pulmonar Obstrutiva Crônica/dietoterapia , Adulto , Idoso , Beta vulgaris , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Pessoa de Meia-Idade , Nitratos/sangue , Oxigênio/metabolismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Troca Gasosa Pulmonar , Caminhada
8.
Nitric Oxide ; 40: 67-74, 2014 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-24858657

RESUMO

BACKGROUND: In this substudy of the effect of dietary nitrate on blood pressure, endothelial function, and insulin sensitivity in type 2 diabetes, we report the development of a novel nitrate depleted beetroot juice for use clinical trials and determine if dietary nitrate supplementation improved cognitive function in patients with type 2 diabetes mellitus. METHODS: Beetroot juice was treated with the anion exchange resin Purolite A520e. UV-vis-spectrophotometry, and a blind taste test were performed along with determination of sugar content, measurement of ascorbate and dehydroascorbate, the ionic composition of juice and Proton NMR. Subsequently, 27 patients, age 67.2±4.9 years, (18 male) were recruited for a double blind, randomised, placebo-controlled crossover trial. Participants were randomised to begin in either order beetroot juice (nitrate content 7.5 mmol per 250 ml) or placebo (nitrate depleted beetroot juice nitrate content 0.002 mmol per 250 ml). At the end of each 2 week supplementation period cognitive function was assessed using E-prime, E-Studio software with 5 separate tests being performed. The tests utilised in the present study have been adapted from the Cambridge Neuropsychological Test Automated Battery (CANTAB). RESULTS: The differences in the UV-vis spectra were comparable to the natural variation found in differing cultivars. There were no discernable differences in taste, sugar content, or Proton NMR. Ascorbate and dehydroascorbate were undetectable in either juice. After 2 weeks of beetroot juice simple reaction time was significantly quicker in the active arm at 327±40 ms versus 341.8±52.7 ms in the placebo arm, mean difference 13.9±25.6 ms (95% CI 3.8-24.0 ms), p=0.009. No other measures of cognitive function differed between treatment arms. CONCLUSION: We have developed an effective placebo beetroot juice for use in trials of supplementation of dietary nitrate. Two weeks supplementation of the diet with 7.5 mmol of nitrate per day caused a significant improvement in simple reaction time in individuals with T2DM.


Assuntos
Beta vulgaris/química , Bebidas , Diabetes Mellitus Tipo 2/tratamento farmacológico , Suplementos Nutricionais , Nitratos/administração & dosagem , Nitratos/uso terapêutico , Tempo de Reação/efeitos dos fármacos , Idoso , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Nitratos/farmacologia , Placebos
9.
Free Radic Biol Med ; 60: 89-97, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23395779

RESUMO

Diets rich in green, leafy vegetables have been shown to lower blood pressure (BP) and reduce the risk of cardiovascular disease. Green, leafy vegetables and beetroot are particularly rich in inorganic nitrate. Dietary nitrate supplementation, via sequential reduction to nitrite and NO, has previously been shown to lower BP and improve endothelial function in healthy humans. We sought to determine if supplementing dietary nitrate with beetroot juice, a rich source of nitrate, will lower BP and improve endothelial function and insulin sensitivity in individuals with type 2 diabetes (T2DM). Twenty-seven patients, age 67.2±4.9 years (18 male), were recruited for a double-blind, randomized, placebo-controlled crossover trial. Participants were randomized to begin, in either order, a 2-week period of supplementation with 250ml beetroot juice daily (active) or 250ml nitrate-depleted beetroot juice (placebo). At the conclusion of each intervention period 24-h ambulatory blood pressure monitoring, tests of macro- and microvascular endothelial function, and a hyperinsulinemic isoglycemic clamp were performed. After 2 weeks administration of beetroot juice mean ambulatory systolic BP was unchanged: 134.6±8.4mmHg versus 135.1±7.8mmHg (mean±SD), placebo vs active-mean difference of -0.5mmHg (placebo-active), p=0.737 (95% CI -3.9 to 2.8). There were no changes in macrovascular or microvascular endothelial function or insulin sensitivity. Supplementation of the diet with 7.5mmol of nitrate per day for 2 weeks caused an increase in plasma nitrite and nitrate concentration, but did not lower BP, improve endothelial function, or improve insulin sensitivity in individuals with T2DM.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Diabetes Mellitus Tipo 2/dietoterapia , Suplementos Nutricionais , Óxido Nítrico/metabolismo , Nitritos/sangue , Idoso , Beta vulgaris/química , Doenças Cardiovasculares/dietoterapia , Doenças Cardiovasculares/patologia , Diabetes Mellitus Tipo 2/patologia , Endotélio/efeitos dos fármacos , Endotélio/fisiologia , Feminino , Humanos , Resistência à Insulina/fisiologia , Masculino , Pessoa de Meia-Idade , Nitratos/administração & dosagem , Nitratos/química , Verduras/química
10.
Am J Physiol Regul Integr Comp Physiol ; 304(2): R73-83, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23174856

RESUMO

Dietary nitrate (NO(3)(-)) supplementation has been shown to reduce resting blood pressure and alter the physiological response to exercise in young adults. We investigated whether these effects might also be evident in older adults. In a double-blind, randomized, crossover study, 12 healthy, older (60-70 yr) adults supplemented their diet for 3 days with either nitrate-rich concentrated beetroot juice (BR; 2 × 70 ml/day, ∼9.6 mmol/day NO(3)(-)) or a nitrate-depleted beetroot juice placebo (PL; 2 × 70 ml/day, ∼0.01 mmol/day NO(3)(-)). Before and after the intervention periods, resting blood pressure and plasma [nitrite] were measured, and subjects completed a battery of physiological and cognitive tests. Nitrate supplementation significantly increased plasma [nitrite] and reduced resting systolic (BR: 115 ± 9 vs. PL: 120 ± 6 mmHg; P < 0.05) and diastolic (BR: 70 ± 5 vs. PL: 73 ± 5 mmHg; P < 0.05) blood pressure. Nitrate supplementation resulted in a speeding of the Vo(2) mean response time (BR: 25 ± 7 vs. PL: 28 ± 7 s; P < 0.05) in the transition from standing rest to treadmill walking, although in contrast to our hypothesis, the O(2) cost of exercise remained unchanged. Functional capacity (6-min walk test), the muscle metabolic response to low-intensity exercise, brain metabolite concentrations, and cognitive function were also not altered. Dietary nitrate supplementation reduced resting blood pressure and improved Vo(2) kinetics during treadmill walking in healthy older adults but did not improve walking or cognitive performance. These results may have implications for the enhancement of cardiovascular health in older age.


Assuntos
Beta vulgaris , Pressão Sanguínea/efeitos dos fármacos , Cognição/efeitos dos fármacos , Dieta , Suplementos Nutricionais , Músculo Esquelético/efeitos dos fármacos , Nitratos/administração & dosagem , Consumo de Oxigênio/efeitos dos fármacos , Fatores Etários , Idoso , Envelhecimento , Bebidas , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Estudos Cross-Over , Método Duplo-Cego , Inglaterra , Teste de Esforço , Tolerância ao Exercício/efeitos dos fármacos , Feminino , Humanos , Cinética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , Testes Neuropsicológicos , Nitratos/sangue , Fosfocreatina/metabolismo , Raízes de Plantas , Caminhada
11.
Med Sci Sports Exerc ; 43(6): 1125-31, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21471821

RESUMO

PURPOSE: Dietary nitrate supplementation has been shown to reduce the O2 cost of submaximal exercise and to improve high-intensity exercise tolerance. However, it is presently unknown whether it may enhance performance during simulated competition. The present study investigated the effects of acute dietary nitrate supplementation on power output (PO), VO2, and performance during 4- and 16.1-km cycling time trials (TT). METHODS: After familiarization, nine club-level competitive male cyclists were assigned in a randomized, crossover design to consume 0.5 L of beetroot juice (BR; containing ∼ 6.2 mmol of nitrate) or 0.5 L of nitrate-depleted BR (placebo, PL; containing ∼ 0.0047 mmol of nitrate), ∼ 2.5 h before the completion of a 4- and a 16.1-km TT. RESULTS: BR supplementation elevated plasma [nitrite] (PL = 241 ± 125 vs BR = 575 ± 199 nM, P < 0.05). The VO2 values during the TT were not significantly different between the BR and PL conditions at any elapsed distance (P > 0.05), but BR significantly increased mean PO during the 4-km (PL = 279 ± 51 vs BR = 292 ± 44 W, P < 0.05) and 16.1-km TT (PL = 233 ± 43 vs BR = 247 ± 44 W, P < 0.01). Consequently, BR improved 4-km performance by 2.8% (PL = 6.45 ± 0.42 vs BR = 6.27 ± 0.35 min, P < 0.05) and 16.1-km performance by 2.7% (PL = 27.7 ± 2.1 vs BR = 26.9 ± 1.8 min, P < 0.01). CONCLUSIONS: These results suggest that acute dietary nitrate supplementation with 0.5 L of BR improves cycling economy, as demonstrated by a higher PO for the same VO2 and enhances both 4- and 16.1-km cycling TT performance.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Suplementos Nutricionais , Nitratos/uso terapêutico , Bebidas , Pressão Sanguínea , Estudos Cross-Over , Humanos , Masculino , Nitritos/sangue , Adulto Jovem
12.
J Appl Physiol (1985) ; 110(3): 591-600, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21071588

RESUMO

Dietary supplementation with beetroot juice (BR) has been shown to reduce resting blood pressure and the O(2) cost of submaximal exercise and to increase tolerance to high-intensity cycling. We tested the hypothesis that the physiological effects of BR were consequent to its high NO(3)(-) content per se, and not the presence of other potentially bioactive compounds. We investigated changes in blood pressure, mitochondrial oxidative capacity (Q(max)), and physiological responses to walking and moderate- and severe-intensity running following dietary supplementation with BR and NO(3)(-)-depleted BR [placebo (PL)]. After control (nonsupplemented) tests, nine healthy, physically active male subjects were assigned in a randomized, double-blind, crossover design to receive BR (0.5 l/day, containing ∼6.2 mmol of NO(3)(-)) and PL (0.5 l/day, containing ∼0.003 mmol of NO(3)(-)) for 6 days. Subjects completed treadmill exercise tests on days 4 and 5 and knee-extension exercise tests for estimation of Q(max) (using (31)P-magnetic resonance spectroscopy) on day 6 of the supplementation periods. Relative to PL, BR elevated plasma NO(2)(-) concentration (183 ± 119 vs. 373 ± 211 nM, P < 0.05) and reduced systolic blood pressure (129 ± 9 vs. 124 ± 10 mmHg, P < 0.01). Q(max) was not different between PL and BR (0.93 ± 0.05 and 1.05 ± 0.22 mM/s, respectively). The O(2) cost of walking (0.87 ± 0.12 and 0.70 ± 0.10 l/min in PL and BR, respectively, P < 0.01), moderate-intensity running (2.26 ± 0.27 and 2.10 ± 0.28 l/min in PL and BR, respectively, P < 0.01), and severe-intensity running (end-exercise O(2) uptake = 3.77 ± 0.57 and 3.50 ± 0.62 l/min in PL and BL, respectively, P < 0.01) was reduced by BR, and time to exhaustion during severe-intensity running was increased by 15% (7.6 ± 1.5 and 8.7 ± 1.8 min in PL and BR, respectively, P < 0.01). In contrast, relative to control, PL supplementation did not alter plasma NO(2)(-) concentration, blood pressure, or the physiological responses to exercise. These results indicate that the positive effects of 6 days of BR supplementation on the physiological responses to exercise can be ascribed to the high NO(3)(-) content per se.


Assuntos
Beta vulgaris/química , Suplementos Nutricionais , Nitratos/administração & dosagem , Consumo de Oxigênio/fisiologia , Extratos Vegetais/administração & dosagem , Corrida/fisiologia , Caminhada/fisiologia , Administração Oral , Bebidas , Marcha/efeitos dos fármacos , Marcha/fisiologia , Humanos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Adulto Jovem
13.
J Biomol Screen ; 13(6): 486-93, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18566482

RESUMO

Fluorescent detection of calcium mobilization has been used successfully to identify modulators of G-protein-coupled receptors (GPCRs); however, inherent issues with fluorescence may limit its potential for high-throughput screening miniaturization. The data presented here demonstrate that the calcium-sensitive photoprotein aequorin (AequoScreen), when compared with FLUO-4 in the same cellular background, allows for miniaturization of functional kinetic calcium flux assays, in which the rank order of potency and efficacy was maintained for a series of diverse small-molecule modulators. Small-volume (<10 microL) 384- and 1536-well aequorin assays were implemented by integration of acoustic dispensing (Echo 550) and kinetic flash luminometry (CyBi Lumax). The enhanced high signal-to-background ratios observed relative to fluorescence were readily manipulated by altering per-well cell densities and yielded acceptable screening statistics in miniaturized format for both agonist and antagonist screening scenarios. In addition, the authors demonstrate the feasibility of using agonist concentrations less than EC(50) in a miniaturized antagonist assay. These features, coupled with improved sample handling, should enhance sensitivity and provide the benefits of miniaturization including cost reduction and throughput gains.


Assuntos
Equorina/metabolismo , Cálcio/metabolismo , Substâncias Luminescentes/metabolismo , Receptor 5-HT2B de Serotonina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Bioensaio , Células CHO , Cricetinae , Cricetulus , Avaliação Pré-Clínica de Medicamentos , Estudos de Viabilidade , Humanos , Miniaturização , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/efeitos dos fármacos
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