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1.
Front Allergy ; 3: 994947, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36249343

RESUMO

Introduction: Exercise-induced bronchoconstriction (EIB) is a prevalent condition in athletes. EIB screening studies identify many athletes with undiagnosed EIB. Moreover, there is a poor relationship between EIB and dyspnea symptoms recalled from memory. Purpose: This study investigated: (I) the prevalence of EIB in British university field hockey athletes; (II) the effect of sex and diagnostic criteria on EIB prevalence; and (III) the association between EIB and contemporaneous dyspnea symptoms. Methods: 52 field hockey athletes (age: 20 ± 2 years; height: 173 ± 9 cm; body mass: 72 ± 10 kg; male = 31; female = 22) completed a eucapnic voluntary hyperpnea (EVH) test with multi-dimensional dyspnea scores measured 3-10 mins post-EVH. A test was deemed positive (EIB+) if a fall index (FI) ≥10% in FEV1 occurred at two consecutive time points post-test (FIATS). Two further criteria were used to assess the effect of diagnostic criteria on prevalence: FI≥10%, determined by a pre-to-post-EVH fall in FEV1 of ≥10% at any single time-point; and FI≥10%-NORM calculated as FI≥10% but with the fall in FEV1 normalized to the mean ventilation achieved during EVH. Results: EIB prevalence was 19% and greater in males (30%) than females (5%). In EIB+ athletes, 66% did not have a previous diagnosis of EIB or asthma and were untreated. Prevalence was significantly influenced by diagnostic criteria (P = 0.002) ranging from 19% (FIATS) to 38% (FI≥10%-NORM). Dyspnea symptoms were higher in EIB+ athletes (P ≤ 0.031), produced significant area under the curve for receive operator characteristics (AUC ≥ 0.778, P ≤ 0.011) and had high negative prediction values (≥96%). Conclusion: Overall, 19% of university field hockey athletes had EIB, and most were previously undiagnosed and untreated. EVH test diagnostic criteria significantly influences prevalence rates, thus future studies should adopt the ATS criteria (FIATS). Contemporaneous dyspnea symptoms were associated with bronchoconstriction and had high negative prediction values. Therefore, contemporaneous dyspnea scores may provide a useful tool in excluding a diagnosis of EIB.

2.
Eur Spine J ; 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36181555

RESUMO

INTRODUCTION: Rigid cervical spine following trauma immobilization is recommended to reduce neurological disability and provide spinal stability. Soft collars have been proposed as a good alternative because of the complications related to rigid collars. The purpose of this study was to perform a systematic review on soft and rigid collars in the prehospital management of cervical trauma. METHOD: A systematic review was performed following the PRISMA guidelines. Search terms were (immobilization) AND (collar) AND ((neck) OR (cervical)) to evaluate the range of motion (ROM) and evidence of clinical outcome for soft and rigid collars. RESULTS: A total of 18 studies met eligibility criteria including 2 clinical studies and 16 articles investigating the range of motion (ROM). Four hundred and ninety-six patients at a mean age of 32.5 years (SD 16.8) were included. Measurements were performed in a seated position in twelve studies. Eight articles reported the ROM without a collar, 7 with a soft collar, and 15 with a rigid collar. There was no significant difference in flexion/extension, bending and rotation following immobilization with soft collars compared to no collar. Rigid collars provided significantly higher stability compared to no collar (p < 0.005) and to soft collars in flexion/extension and rotation movements (p < 0.05). The retrospective clinical studies showed no significant differences in secondary spinal cord injuries for soft collar (0.5%) and for rigid collar (1.1%). One study, comparing immobilization without a collar compared to that with a rigid collar, found a significant difference in neurologic deficiency and supraclavicular nerve lesion. CONCLUSION: Although rigid collars provide significant higher stability to no collar and to soft collars in flexion/ extension and rotation movements, clinical studies could not confirm a difference in neurological outcome. LEVEL OF EVIDENCE: II, Systematic Review.

3.
J Pers Med ; 12(10)2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36294697

RESUMO

Smartphones and their associated applications are used frequently by patients and clinicians alike. Despite the technology being widely accessible, their use to aid in rehabilitation is yet to be adopted. The SARS CoV-2 pandemic has presented an opportunity to expedite their integration given the difficulty patients currently have in accessing healthcare. The aim of this study was to perform a systematic literature review on the use of smartphone rehabilitation applications compared to standard physiotherapy for back pain. We conducted a search of Medline/Pubmed and google databases using the search terms [APP] AND [[Orthopaedic] OR [Neurosurgery]], following the PRISMA guidelines. All prospective studies investigating rehabilitation applications for back pain or following spine surgery were included. A total of nine studies met the inclusion criteria which investigated 7636 patients, of which 92.4% were allocated to the interventional group (n = 7055/7636) with a follow up of 4 weeks to 6 months. All except one study reported on patients experiencing back pain on average for 19.6 ± 11.6 months. The VAS-pain score was presented in all studies without significance between the interventional and control group (p = 0.399 before and p = 0.277 after intervention). Only one research group found significantly higher improvement in PROMs for the application group, whereas the remaining showed similar results compared to the control group. Using application-based rehabilitation programs provides an easily accessible alternative or substitute to traditional physiotherapy for patients with back pain. Given that smartphones are so prevalent in activities in our daily lives, this will enhance and improve rehabilitation if patients are self-dedicated and compliant.

4.
N Engl J Med ; 387(19): 1735-1746, 2022 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-36214599

RESUMO

BACKGROUND: Exposure during pregnancy to household air pollution caused by the burning of solid biomass fuel is associated with adverse health outcomes, including low birth weight. Whether the replacement of a biomass cookstove with a liquefied petroleum gas (LPG) cookstove would result in an increase in birth weight is unclear. METHODS: We performed a randomized, controlled trial involving pregnant women (18 to <35 years of age and at 9 to <20 weeks' gestation as confirmed on ultrasonography) in Guatemala, India, Peru, and Rwanda. The women were assigned in a 1:1 ratio to use a free LPG cookstove and fuel (intervention group) or to continue using a biomass cookstove (control group). Birth weight, one of four prespecified primary outcomes, was the primary outcome for this report; data for the other three outcomes are not yet available. Birth weight was measured within 24 hours after birth. In addition, 24-hour personal exposures to fine particulate matter (particles with a diameter of ≤2.5 µm [PM2.5]), black carbon, and carbon monoxide were measured at baseline and twice during pregnancy. RESULTS: A total of 3200 women underwent randomization; 1593 were assigned to the intervention group, and 1607 to the control group. Uptake of the intervention was nearly complete, with traditional biomass cookstoves being used at a median rate of less than 1 day per month. After randomization, the median 24-hour personal exposure to fine particulate matter was 23.9 µg per cubic meter in the intervention group and 70.7 µg per cubic meter in the control group. Among 3061 live births, a valid birth weight was available for 94.9% of the infants born to women in the intervention group and for 92.7% of infants born to those in the control group. The mean (±SD) birth weight was 2921±474.3 g in the intervention group and 2898±467.9 g in the control group, for an adjusted mean difference of 19.6 g (95% confidence interval, -10.1 to 49.2). CONCLUSIONS: The birth weight of infants did not differ significantly between those born to women who used LPG cookstoves and those born to women who used biomass cookstoves. (Funded by the National Institutes of Health and the Bill and Melinda Gates Foundation; HAPIN ClinicalTrials.gov number, NCT02944682.).


Assuntos
Poluição do Ar em Ambientes Fechados , Peso ao Nascer , Culinária , Material Particulado , Petróleo , Feminino , Humanos , Gravidez , Poluição do Ar em Ambientes Fechados/efeitos adversos , Poluição do Ar em Ambientes Fechados/análise , Biomassa , Culinária/métodos , Material Particulado/efeitos adversos , Material Particulado/análise , Petróleo/efeitos adversos , Petróleo/análise , Recém-Nascido , Adolescente , Adulto Jovem , Adulto
5.
Clin Spine Surg ; 2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36253913

RESUMO

STUDY DESIGN: Case report and literature review. OBJECTION: Aim of this study was to summarize the current evidence base behind subacute posttraumatic ascending myelopathy (SPAM) including the epidemiology, presentation, diagnosis, prognosis, and etiology. SUMMARY OF BACKGROUND DATA: SPAM is a rare, potentially fatal disorder which is not attributable to ongoing mechanical instability, syrinx formation, or iatrogenic causes. METHODS: A systematic literature search on SPAM was performed on Medline, Ovid, Cochrane, Embase, and PubMed databases between 1969 and 2021. Cases were reviewed and the findings summarized. Further evidence was reviewed to support the hypothesis that disruption of cerebrospinal fluid (CSF) circulation is the underlying etiology of the condition. RESULTS: It is estimated to occur in 0.4%-0.7% of spinal cord injuries and may have a mortality of up to 10%. The most likely etiology disruption of CSF circulation leading to further damage to the spinal cord presumably through pressure mediated effects such as a reduction in cellular perfusion. CONCLUSION: There is effectively no treatment of this condition, however, with interest developing in monitoring of CSF pressures during spinal cord injury this may help confirm the etiology, and allow the suggestion of therapies such as drains or expansion duraplasty to reduce spinal cord pressures. LEVEL OF EVIDENCE: Level II-case report and systematic review.

6.
Chem Res Toxicol ; 35(11): 1974-1982, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36178476

RESUMO

In this work, we carried out neurochemical and behavioral analysis of zebrafish (Danio rerio) treated with rotenone, an agent used to chemically induce a syndrome resembling Parkinson's disease (PD). Dopamine release, measured with fast-scan cyclic voltammetry (FSCV) at carbon-fiber electrodes in acutely harvested whole brains, was about 30% of that found in controls. Uptake, represented by the first order rate constant (k) and the half-life (t1/2) determined by nonlinear regression modeling of the stimulated release plots, was also diminished. Behavioral analysis revealed that rotenone treatment increased the time required for zebrafish to reach a reward within a maze by more than 50% and caused fish to select the wrong pathway, suggesting that latent learning was impaired. Additionally, zebrafish treated with rotenone suffered from diminished locomotor activity, swimming shorter distances with lower mean velocity and acceleration. Thus, the neurochemical and behavioral approaches, as applied, were able to resolve rotenone-induced differences in key parameters. This approach may be effective for screening therapies in this and other models of neurodegeneration.


Assuntos
Doença de Parkinson , Rotenona , Animais , Rotenona/farmacologia , Peixe-Zebra/metabolismo , Dopamina/metabolismo , Modelos Animais de Doenças , Cognição
7.
J Electrochem Soc ; 169(4)2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36157165

RESUMO

Selective serotonin reuptake inhibitors (SSRIs) have been used for decades to treat disorders linked to serotonin dysregulation in the brain. Moreover, SSRIs are often used in studies aimed at measuring serotonin with fast-scan cyclic voltammetry (FSCV) in living tissues. Here, we show that three different SSRIs - fluoxetine, escitalopram, and sertraline - significantly diminish the faradaic oxidation current of serotonin when employing the commonly used Jackson waveform. Coating carbon-fiber microelectrodes (CFMs) with Nafion resulted in further degradation of peak current, increased response times, and decreased background charging currents compared to bare CFMs. To decrease fouling, we employed a recently published extended serotonin waveform, which scans to a maximum positive potential of +1.3 V, rather than +1.0 V used in the Jackson waveform. Use of this waveform with bare CFMs alleviated the decrease in faradaic current, indicating decreased electrode fouling. Collectively, our results suggest that fouling considerations are important when designing FSCV experiments that employ SSRIs and that they can be overcome by using the appropriate waveform.

8.
ACS Chem Neurosci ; 13(19): 2863-2873, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36099546

RESUMO

Zebrafish (Danio rerio) are ideal model organisms for investigating nervous system function, both in health and disease. Nevertheless, functional characteristics of dopamine (DA) release and uptake regulation are still not well-understood in zebrafish. In this study, we assessed D3 autoreceptor function in the telencephalon of whole zebrafish brains ex vivo by measuring the electrically stimulated DA release ([DA]max) and uptake at carbon fiber microelectrodes with fast-scan cyclic voltammetry. Treatment with pramipexole and 7-OH-DPAT, selective D3 autoreceptor agonists, sharply decreased [DA]max. Conversely, SB277011A, a selective D3 antagonist, nearly doubled [DA]max and decreased k, the first-order rate constant for the DA uptake, to about 20% of its original value. Treatment with desipramine, a selective norepinephrine transporter blocker, failed to increase current, suggesting that our electrochemical signal arises solely from the release of DA. Furthermore, blockage of DA uptake with nomifensine-reversed 7-OH-DPAT induced decreases in [DA]max. Collectively, our data show that, as in mammals, D3 autoreceptors regulate DA release, likely by inhibiting uptake. The results of this study are useful in the further development of zebrafish as a model organism for DA-related neurological disorders such as Parkinson's disease, schizophrenia, and drug addiction.


Assuntos
Autorreceptores , Peixe-Zebra , Animais , Autorreceptores/metabolismo , Encéfalo/metabolismo , Fibra de Carbono , Desipramina , Dopamina , Estimulação Elétrica , Mamíferos/metabolismo , Nomifensina , Proteínas da Membrana Plasmática de Transporte de Norepinefrina , Pramipexol , Receptores de Dopamina D2/metabolismo , Tetra-Hidronaftalenos , Peixe-Zebra/metabolismo
9.
ACS Chem Neurosci ; 13(19): 2924-2931, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36113115

RESUMO

Alzheimer's disease (AD) is a progressive, fatal, neurodegenerative disorder for which only treatments of limited efficacy are available. Despite early mentions of dementia in the ancient literature and the first patient diagnosed in 1906, the underlying causes of AD are not well understood. This study examined the possible role of dopamine, a neurotransmitter that is involved in cognitive and motor function, in AD. We treated adult zebrafish (Danio rerio) with okadaic acid (OKA) to model AD and assessed the resulting behavioral and neurochemical changes. We then employed a latent learning paradigm to assess cognitive and motor function followed by neurochemical analysis with fast-scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes to measure the electrically stimulated dopamine release. The behavioral assay showed that OKA treatment caused fish to have lower motivation to reach the goal chamber, resulting in impeded learning and decreased locomotor activity compared to controls. Our voltammetric measurements revealed that the peak dopamine overflow in OKA-treated fish was about one-third of that measured in controls. These findings highlight the profound neurochemical changes that may occur in AD. Furthermore, they demonstrate that applying the latent learning paradigm and FSCV to zebrafish is a promising tool for future neurochemical studies and may be useful for screening drugs for the treatment of AD.


Assuntos
Doença de Alzheimer , Dopamina , Animais , Fibra de Carbono , Microeletrodos , Neurotransmissores , Ácido Okadáico , Peixe-Zebra
10.
Eur Spine J ; 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35727373

RESUMO

INTRODUCTION: Hirayama syndrome is likely caused by a forward displacement of the posterior dura during cervical flexion leading to changes in the muscles of the fingers and wrist. The aim of this systematic review was to document the number of reported cases, the necessity of dynamic MRI of the cervical spine and the subsequent treatment. METHODS AND MATERIALS: A systematic review was conducted and the Pubmed/Medbase, Cochrane, Google, Embase and Ovid database were searched for (Hirayama) AND ((disease) OR (syndrome)). A total of 42 studies were included for analysis reporting 2311 patients. RESULTS: The mean age was 20.2 ± 2.26 years and predominantly males (92.8%) were identified. On MRI the "snake eyes" appearance of the spinal cord was present in 27.8% and the typical time between onset of symptoms and diagnosis was 41.5 ± 16.4 months. A variety of different treatments have been reported, although there is no substantial evidence that any of them are superior to observation. CONCLUSION: The delay in diagnosis from initial presentation of symptoms shows that this condition may be underdiagnosed in a variety of cases. Further, this study shows the necessity of either a dynamic MRI in flexion or a static MRI scan in neutral position and in flexion, to identify functional spinal and/or foraminal stenosis for a prompt diagnosis and subsequent treatment.

11.
Sci Rep ; 12(1): 5110, 2022 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-35332216

RESUMO

Migraine is one of the most common and debilitating neurological disorders worldwide. External Trigeminal Nerve Stimulation (e-TNS) is a non-pharmacological, non-invasive therapeutic alternative for patients with migraine. The TEAM study was a prospective, multicenter, randomized, double-blind, sham-controlled, Phase 3 trial for 2-h, continuous, e-TNS treatment of a single moderate or severe migraine attack at home. A total of 538 adults meeting the International Classification of Headache Disorders 3rd edition criteria for 2-8 migraine headache days per month were recruited and randomized in a 1:1 ratio to 2-h active or sham stimulation. Migraine pain levels and most bothersome migraine-associated symptoms (MBS) were recorded at baseline, 2 h, and 24 h using a paper diary. The primary endpoints for the study were pain freedom at 2 h and freedom from the MBS at 2 h. The secondary endpoints were pain relief at 2 h, absence of most bothersome migraine-associated symptoms (MBSs) at 2 h, acute medication use within 24 h after treatment, sustained pain freedom at 24 h, and sustained pain relief at 24 h. Adverse event data was also collected and compared between groups. Five hundred thirty-eight patients were randomized to either the verum (n = 259) or sham (n = 279) group and were included in an intention-to-treat analysis. The percentage of patients with pain freedom at 2 h was 7.2% higher in verum (25.5%) compared to sham (18.3%; p = 0.043). Resolution of most bothersome migraine-associated symptom was 14.1% higher in verum (56.4%) compared to sham (42.3%; p = 0.001). With regards to secondary outcomes, pain relief at 2 h was 14.3% higher in verum (69.5%) than sham (55.2%; p = 0.001), absence of all migraine-associated symptoms at 2 h was 8.4% higher in verum (42.5%) than sham (34.1%; p = 0.044), sustained pain freedom and pain relief at 24 h was 7.0% and 11.5% higher in verum (22.8 and 45.9%) than sham (15.8 and 34.4%; p = 0.039 and .006, respectively). No serious adverse events were reported. Treatment with 2-h e-TNS is a safe and effective, non-invasive, and non-pharmacological alternative for the acute treatment of migraine attacks in an at-home setting.Trial registration Clinicaltrials.gov Identifier: NCT03465904. Registered 14/03/2018. https://www.clinicaltrials.gov/ct2/show/record/NCT03465904 .


Assuntos
Transtornos de Enxaqueca , Adulto , Método Duplo-Cego , Cefaleia , Humanos , Transtornos de Enxaqueca/tratamento farmacológico , Naftalenossulfonatos , Estudos Prospectivos , Resultado do Tratamento , Nervo Trigêmeo
12.
Anal Chem ; 94(6): 2942-2949, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35107979

RESUMO

Oxytocin is a nonapeptide hormone involved in numerous physiological functions. Real-time electrochemical measurements of oxytocin in living tissue are challenging due to electrode fouling and the large potentials needed to oxidize the tyrosine residue. Here, we used fast-scan cyclic voltammetry at carbon-fiber microelectrodes and flow injection analysis to optimize a waveform for the measurement of oxytocin. This optimized waveform employed an accumulation potential of -0.6 V, multiple scan rates, and a 3 ms holding potential at a positive, oxidizing potential of +1.4 V before linearly scanning the potential back to -0.6 V (versus Ag/AgCl). We obtained a limit of quantitation of 0.34 ± 0.02 µM, and our electrodes did not foul upon multiple injections. Moreover, to demonstrate the utility of our method, we measured the release of oxytocin, evoked by light application and mechanical perturbation, in whole brains from genetically engineered adult zebrafish that express channelrhodopsin-2 selectively on oxytocinergic neurons. Collectively, this work expands the toolkit for the measurement of peptides in living tissue preparations.


Assuntos
Ocitocina , Peixe-Zebra , Animais , Fibra de Carbono , Microeletrodos , Neurônios
13.
Eur J Appl Physiol ; 121(12): 3333-3347, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34432148

RESUMO

PURPOSE: The mechanisms that explain the ability of trained martial arts practitioners to produce and resist greater forces than untrained individuals to aid combat performance are not fully understood. We investigated whether the greater ability of trained martial arts practitioners to produce and resist forces was associated with an enhanced control of respiratory pressures and neuromuscular activation of the respiratory, abdominal, and pelvic floor musculature. METHODS: Nine trained martial arts practitioners and nine untrained controls were instrumented with skin-surface electromyography (EMG) on the sternocleidomastoid, rectus abdominis, and the group formed by the transverse abdominal and internal oblique muscles (EMGtra/io). A multipair oesophageal EMG electrode catheter measured gastric (Pg), transdiaphragmatic (Pdi), and oesophageal (Pe) pressures and EMG of the crural diaphragm (EMGdi). Participants performed Standing Isometric Unilateral Chest Press (1) and Standing Posture Control (2) tasks. RESULTS: The trained group produced higher forces normalised to body mass2/3 (0.033 ± 0.01 vs. 0.025 ± 0.007 N/kg2/3 mean force in Task 1), lower Pe, and higher Pdi in both tasks. Additionally, they produced higher Pg (73 ± 42 vs. 49 ± 19 cmH2O mean Pg) and EMGtra/io in Task 1 and higher EMGdi in Task 2. The onset of Pg with respect to the onset of force production was earlier, and the relative contributions of Pg/Pe and Pdi/Pe were higher in the trained group in both tasks. CONCLUSION: Our findings demonstrate that trained martial arts practitioners utilised a greater contribution of abdominal and diaphragm musculature to chest wall recruitment and higher Pdi to produce and resist higher forces.


Assuntos
Músculos Abdominais/fisiologia , Artes Marciais/fisiologia , Diafragma da Pelve/fisiologia , Músculos Respiratórios/fisiologia , Adulto , Estudos de Casos e Controles , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor , Testes de Função Respiratória
14.
Physiol Rep ; 9(8): e14831, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33938126

RESUMO

Respiratory pressure responses to cervical magnetic stimulation are important measurements in monitoring the mechanical function of the respiratory muscles. Pressures can be measured using balloon catheters or a catheter containing integrated micro-transducers. However, no research has provided a comprehensive analysis of their pressure measurement characteristics. Accordingly, the aim of this study was to provide a comparative analysis of these characteristics in two separate experiments: (1) in vitro with a reference pressure transducer following a controlled pressurization; and (2) in vivo following cervical magnetic stimulations. In vitro the micro-transducer catheter recorded pressure amplitudes and areas which were in closer agreement to the reference pressure transducer than the balloon catheter. In vivo there was a main effect for stimulation power and catheter for esophageal (Pes ), gastric (Pga ), and transdiaphragmatic (Pdi ) pressure amplitudes (p < 0.001) with the micro-transducer catheter recording larger pressure amplitudes. There was a main effect of stimulation power (p < 0.001) and no main effect of catheter for esophageal (p = 0.481), gastric (p = 0.923), and transdiaphragmatic (p = 0.964) pressure areas. At 100% stimulator power agreement between catheters for Pdi amplitude (bias =6.9 cmH2 O and LOA -0.61 to 14.27 cmH2 O) and pressure areas (bias = -0.05 cmH2 O·s and LOA -1.22 to 1.11 cmH2 O·s) were assessed. At 100% stimulator power, and compared to the balloon catheters, the micro-transducer catheter displayed a shorter 10-90% rise time, contraction time, latency, and half-relaxation time, alongside greater maximal rates of change in pressure for esophageal, gastric, and transdiaphragmatic pressure amplitudes (p < 0.05). These results suggest that caution is warranted if comparing pressure amplitude results utilizing different catheter systems, or if micro-transducers are used in clinical settings while applying balloon catheter-derived normative values. However, pressure areas could be used as an alternative point of comparison between catheter systems.


Assuntos
Cateteres/efeitos adversos , Transdutores de Pressão/efeitos adversos , Adulto , Cateteres/normas , Esôfago/fisiologia , Feminino , Humanos , Masculino , Manometria/instrumentação , Pressão , Testes de Função Respiratória/instrumentação , Músculos Respiratórios/fisiologia , Transdutores de Pressão/normas
15.
Crit Care Explor ; 3(1): e0313, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33458681

RESUMO

To develop and characterize a machine learning algorithm to discriminate acute respiratory distress syndrome from other causes of respiratory failure using only ventilator waveform data. DESIGN: Retrospective, observational cohort study. SETTING: Academic medical center ICU. PATIENTS: Adults admitted to the ICU requiring invasive mechanical ventilation, including 50 patients with acute respiratory distress syndrome and 50 patients with primary indications for mechanical ventilation other than hypoxemic respiratory failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pressure and flow time series data from mechanical ventilation during the first 24-hours after meeting acute respiratory distress syndrome criteria (or first 24-hr of mechanical ventilation for non-acute respiratory distress syndrome patients) were processed to extract nine physiologic features. A random forest machine learning algorithm was trained to discriminate between the patients with and without acute respiratory distress syndrome. Model performance was assessed using the area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value. Analyses examined performance when the model was trained using data from the first 24 hours and tested using withheld data from either the first 24 hours (24/24 model) or 6 hours (24/6 model). Area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value were 0.88, 0.90, 0.71, 0.77, and 0.90 (24/24); and 0.89, 0.90, 0.75, 0.83, and 0.83 (24/6). CONCLUSIONS: Use of machine learning and physiologic information derived from raw ventilator waveform data may enable acute respiratory distress syndrome screening at early time points after intubation. This approach, combined with traditional diagnostic criteria, could improve timely acute respiratory distress syndrome recognition and enable automated clinical decision support, especially in settings with limited availability of conventional diagnostic tests and electronic health records.

16.
Med Sci Sports Exerc ; 53(7): 1482-1494, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33481485

RESUMO

INTRODUCTION: The ergogenic effects of respiratory alkalosis induced by prior voluntary hyperventilation (VH) are controversial. This study examined the effects of prior VH on derived parameters from the 3-min all-out cycling test (3MT). METHODS: Eleven men ( = 46 ± 8 mL·kg-1·min-1) performed a 3MT preceded by 15 min of rest (CONT) or VH ( = 38 ± 5 L·min-1) with PETCO2 reduced to 21 ± 1 mm Hg (HYP). End-test power (EP; synonymous with critical power) was calculated as the mean power output over the last 30 s of the 3MT, and the work done above EP (WEP; synonymous with W') was calculated as the power-time integral above EP. RESULTS: At the start of the 3MT, capillary blood PCO2 and [H+] were lower in HYP (25.2 ± 3.0 mm Hg, 27.1 ± 2.6 nmol·L-1) than CONT (43.2 ± 2.0 mm Hg, 40.0 ± 1.5 nmol·L-1) (P < 0.001). At the end of the 3MT, blood PCO2 was still lower in HYP (35.7 ± 5.4 mm Hg) than CONT (40.6 ± 5.0 mm Hg) (P < 0.001). WEP was 10% higher in HYP (19.4 ± 7.0 kJ) than CONT (17.6 ± 6.4 kJ) (P = 0.006), whereas EP was 5% lower in HYP (246 ± 69 W) than CONT (260 ± 74 W) (P = 0.007). The ΔWEP (J·kg-1) between CONT and HYP correlated positively with the PCO2 immediately before the 3MT in HYP (r = 0.77, P = 0.006). CONCLUSION: These findings suggest that acid-base changes elicited by prior VH increase WEP but decrease EP during the all-out 3MT.


Assuntos
Teste de Esforço/normas , Hiperventilação , Consumo de Oxigênio/fisiologia , Adulto , Voluntários Saudáveis , Humanos , Masculino , Adulto Jovem
17.
Anal Chem ; 93(5): 2776-2784, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33492927

RESUMO

Caged compounds are molecules that release a protective substrate to free a biologically active substrate upon treatment with light of sufficient energy and duration. A notable limitation of this approach is difficulty in determining the degree of photoactivation in tissues or opaque solutions because light reaching the desired location is obstructed. Here, we have addressed this issue by developing an in situ electrochemical method in which the amount of caged molecule photorelease is determined by fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes. Using p-hydroxyphenyl glutamate (pHP-Glu) as our model system, we generated a linear calibration curve for oxidation of 4-hydroxyphenylacetic acid (4HPAA), the group from which the glutamate molecule leaves, up to a concentration of 1000 µM. Moreover, we are able to correct for the presence of residual pHP-Glu in solution as well as the light artifact that is produced. A corrected calibration curve was constructed by photoactivation of pHP-Glu in a 3 µL photoreaction vessel and subsequent analysis by high-performance liquid chromatography. This approach has yielded a linear relationship between 4HPAA concentration and oxidation current, allowing the determination of released glutamate independent of the amount of light reaching the chromophore. Moreover, we have successfully validated the newly developed method by in situ measurement in a whole, intact zebrafish brain. This work demonstrates for the first time the in situ electrochemical monitoring of caged compound photochemistry in brain tissue with FSCV, thus facilitating analyses of neuronal function.


Assuntos
Técnicas Eletroquímicas , Peixe-Zebra , Animais , Fibra de Carbono , Microeletrodos , Fotoquímica
18.
Sci Adv ; 6(47)2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33208366

RESUMO

We demonstrate an additive manufacturing approach to produce gradient refractive index glass optics. Using direct ink writing with an active inline micromixer, we three-dimensionally print multimaterial green bodies with compositional gradients, consisting primarily of silica nanoparticles and varying concentrations of titania as the index-modifying dopant. The green bodies are then consolidated into glass and polished, resulting in optics with tailored spatial profiles of the refractive index. We show that this approach can be used to achieve a variety of conventional and unconventional optical functions in a flat glass component with no surface curvature.

19.
J Appl Physiol (1985) ; 129(1): 185-193, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32552433

RESUMO

We questioned whether the respiratory muscles of humans contribute to systemic oxidative stress following inspiratory flow-resistive breathing, whether the amount of oxidative stress is influenced by the level of resistive load, and whether the amount of oxidative stress is related to the degree of diaphragm fatigue incurred. Eight young and healthy participants attended the laboratory for four visits on separate days. During the first visit, height, body mass, lung function, and maximal inspiratory mouth and transdiaphragmatic pressure (Pdimax) were assessed. During visits 2-4, participants undertook inspiratory flow-resistive breathing with either no resistance (control) or resistive loads equivalent to 50 and 70% of their Pdimax (Pdimax50% and Pdimax70%) for 30 min. Participants undertook one resistive load per visit, and the order in which they undertook the loads was randomized. Inspiratory muscle pressures were higher (P < 0.05) during the 5th and Final min of Pdimax50% and Pdimax70% compared with control. Plasma F2-isoprostanes increased (P < 0.05) following inspiratory flow-resistive breathing at Pdimax70%. There were no increases in plasma protein carbonyls or total antioxidant capacity. Furthermore, although we evidenced small reductions in transdiapragmaic twitch pressures (PdiTW) after inspiratory flow-resistive breathing at Pdimax50% and Pdimax70%, this was not related to the increase in plasma F2-isoprostanes. Our novel data suggest that it is only when sufficiently strenuous that inspiratory flow-resistive breathing in humans elicits systemic oxidative stress evidenced by elevated plasma F2-isoprostanes, and based on our data, this is not related to a reduction in PdiTW.NEW & NOTEWORTHY We examined whether the respiratory muscles of humans contribute to systemic oxidative stress following inspiratory flow-resistive breathing, whether the amount of oxidative stress is influenced by the level of resistive load, and whether the amount of oxidative stress is related to the degree of diaphragm fatigue incurred. It is only when sufficiently strenuous that inspiratory flow-resistive breathing elevates plasma F2-isoprostanes, and our novel data show that this is not related to a reduction in transdiaphragmatic twitch pressure.


Assuntos
Diafragma , F2-Isoprostanos , F2-Isoprostanos/metabolismo , Humanos , Fadiga Muscular , Estresse Oxidativo , Respiração , Músculos Respiratórios/metabolismo
20.
Med Sci Sports Exerc ; 52(11): 2402-2411, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32366795

RESUMO

INTRODUCTION: Prior upper body exercise reduces the curvature constant (W') of the hyperbolic power-duration relationship without affecting critical power. This study tested the hypothesis that prior upper body exercise reduces the work done over the end-test power (WEP; analog of W') during a 3-min all-out cycling test (3MT) without affecting the end-test power (EP; analog of critical power). METHODS: Ten endurance-trained men (V˙O2max = 62 ± 5 mL·kg·min) performed a 3MT without (CYC) and with (ARM-CYC) prior severe-intensity, intermittent upper body exercise. EP was calculated as the mean power output over the last 30 s of the 3MT, whereas WEP was calculated as the power-time integral above EP. RESULTS: At the start of the 3MT, plasma [La] (1.8 ± 0.4 vs 14.1 ± 3.4 mmol·L) and [H] (42.8 ± 3.1 vs 58.6 ± 5.5 nmol·L) were higher, whereas the strong ion difference (41.4 ± 2.2 vs 30.9 ± 4.6 mmol·L) and [HCO3] (27.0 ± 1.9 vs 16.9 ± 3.2 mmol·L) were lower during ARM-CYC than CYC (P < 0.010). EP was 12% lower during the 3MT of ARM-CYC (298 ± 52 W) than CYC (338 ± 60 W; P < 0.001), whereas WEP was not different (CYC: 12.8 ± 3.3 kJ vs ARM-CYC: 13.5 ± 4.1 kJ, P = 0.312). EP in CYC was positively correlated with the peak [H] (r = 0.78, P = 0008) and negatively correlated with the lowest [HCO3] (r = -0.74, P = 0.015). CONCLUSIONS: These results suggest that EP during a 3MT in endurance-trained men is sensitive to fatigue-related ionic perturbation.


Assuntos
Ciclismo/fisiologia , Teste de Esforço , Exercício Físico/fisiologia , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Extremidade Superior/fisiologia , Adolescente , Adulto , Humanos , Masculino , Adulto Jovem
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