Neuromuscular electrical stimulation improves exercise tolerance in chronic obstructive pulmonary disease patients with better preserved fat-free mass

BACKGROUND: High-frequency neuromuscular electrical stimulation increases exercise tolerance in patients with advanced chronic obstructive pulmonary disease (COPD patients). However, it is conceivable that its benefits are more prominent in patients with better-preserved peripheral muscle function and structure. OBJECTIVE: To investigate the effects of high-frequency neuromuscular electrical stimulation in COPD patients with better-preserved peripheral muscle function. Design: Prospective and cross-over study. METHODS: Thirty COPD patients were randomly assigned to either home-based, high-frequency neuromuscular electrical stimulation or sham stimulation for six weeks. The training intensity was adjusted according to each subject's tolerance. Fat-free mass, isometric strength, six-minute walking distance and time to exercise intolerance (Tlim) were assessed. RESULTS: Thirteen (46.4%) patients responded to high-frequency neuromuscular electrical stimulation; that is, they had a post/pre &#916; Tlim >10% after stimulation (unimproved after sham stimulation). Responders had a higher baseline fat-free mass and six-minute walking distance than their seventeen (53.6%) non-responding counterparts. Responders trained at higher stimulation intensities; their mean amplitude of stimulation during training was significantly related to their fat-free mass (r = 0.65; p<0.01). Logistic regression revealed that fat-free mass was the single independent predictor of Tlim improvement (odds ratio [95% CI] = 1.15 [1.04-1.26]; p<0.05). CONCLUSIONS: We conclude that high-frequency neuromuscular electrical stimulation improved the exercise capacity of COPD patients with better-preserved fat-free mass because they tolerated higher training stimulus levels. These data suggest that early training with high-frequency neuromuscular electrical stimulation before tissue wasting begins might enhance exercise tolerance in patients with less advanced COPD

Função muscular e qualidade de vida na doença de Crohn

Introduction: Crohn's disease (CD) is an inflammatory bowel disease, marked by exacerbations and remissions periods. Peripheral manifestations in CD may be present with the syndrome of skeletal muscle dysfunction (SMD), which is characterized by loss of muscle strength, fatigue complain, limited exercise capacity and impaired quality of life of these patients. Objective: Evaluate muscle strength, physical capacity and quality of life of patients with CD and compare them with healthy controls. Methods: 18 patients CD and 12 healthy controls matched for age and sex were involved. Peripheral muscle strength evaluated by handgrip strength of the dominant hand and respiratory muscle strength by measures of respiratory muscle strength (maximal inspiratory/expiratory pressure – MIP and MEP). Exercise capacity evaluated by Shuttle test (ST) and the quality of life by the Short-form 36 (SF-36) and by the Inflammatory Bowel Disease Questionnaire (IBDQ). Results: Patients with CD presented a lower respiratory muscle strength (MIP = -68.93 ± 26.61 vs 29.63 ± -100 cmH2O, p = 0.0013 and MEP = 81.07 ± 30.26 vs 108 ± 25.30 cmH2O, p = 0.032) and a tendency the lower peripheral muscle strength (31.72 ± 8.55 vs 39.00 ± 13.37 kgf, p = 0.09). In addition, CD patients presented worse physical capacity on the ST compared to the control group (513.7 ± 237m vs 983.0 ± 263m, p < 0.05) and worse quality of life in 7 of 8 domains of the SF-36 and in all dimensions of the IBDQ. Conclusion: Patients with CD showed muscle functional impairment and poorer quality of life compared to healthy control group. These findings suggest that the assessment and maybe interventions in the muscle function must be used in clinical practice.Introdução: A doença de Crohn (DC) é uma doença inflamatória intestinal marcada por agudizações e remissões. Manifestações sistêmicas na DC podem estar associadas à síndrome da disfunção muscular esquelética (SDM), a qual é caracterizada por perda de força, queixa de fadiga, limitação ao exercício e prejuízo na qualidade de vida. Objetivo: Avaliar a força muscular, a capacidade de exercício e a qualidade de vida de pacientes com DC e compará- los com controles saudáveis. Métodos: Foram envolvidos 18 pacientes com DC e 12 controles saudáveis pareados por idade e sexo. A força muscular periférica foi avaliada pela força de preensão palmar da mão dominante; e a força muscular respiratória pelas medidas de pressões respiratórias máximas (pressão inspiratória/expiratória máxima – PIM e PEM). A capacidade ao exercício foi avaliada por meio do teste de Shuttle (TS) e a qualidade de vida pelo relacionada à saúde pelo Short Form-36 e pelo The Inflammatory Bowel Disease Questionnaire (IBDQ). Resultados: A força muscular respiratória mostrou-se reduzida nos pacientes com DC comparado ao grupo controle (PIM = -68,93 ± 26,61 vs -100 ± 29,63 cmH2O, p = 0,0013 e PEM = 81,07 ± 30,26 vs 108 ± 25,30 cmH2O, p = 0,032) e, com tendência a menor força muscular periférica no grupo de pacientes (31,72 ± 8,55 vs 39,00 ± 13,37 kgf, p = 0,09). Pacientes com DC apresentaram ainda pior capacidade de exercício no TS (513,7 ± 237m vs 983,0 ± 263m, p < 0,05) e pior qualidade de vida comparados aos controles. Conclusão: Pacientes com DC mostraram prejuízo funcional muscular e pior qualidade de vida. Estes achados sugerem que a avaliação e possível intervenção da função muscular deve ser adotada na prática clínica

The pattern and timing of breathing during incremental exercise: a normative study

Clinical evaluation of the pattern and timing of breathing during submaximal exercise can be valuable for the identification of the mechanical ventilatory consequences of different disease processes and for assessing the efficacy of certain interventions.Sedentary individuals (60 male/60 female, aged 20-80 yrs) were randomly selected from >8,000 subjects and submitted to ramp incremental cycle ergometry. Tidal volume (V-T)/ resting inspiratory capacity, respiratory frequency, total respiratory time (Trot), inspiratory time (T-I), expiratory time (T-E), duty cycle (TI/Ttot) and mean inspiratory flow (V-T/T-I) were analysed at selected submaximal ventilatory intensities.Senescence and female sex were associated with a more tachypnoeic breathing pattern during isoventilation. the decline in T-tot was proportional to the TI and TE P reductions, i.e. T-I/T-tot was remarkably constant across age strata, independent of sex. the pattern, but not timing, of breathing was also influenced by weight and height; a set of demographically and anthropometrically based prediction equations are therefore presented.These data provide a frame of reference for assessing the normality of some clinically useful indices of the pattern and timing of breathing during incremental cycle ergometry in sedentary males and females aged 20-80 yrs.Universidade Federal de São Paulo, Pulmonary Funct & Clin Exercise Physiol Unit, Div Resp, Dept Med,Paulista Sch Med, BR-04020050 São Paulo, BrazilUniv Glasgow, Ctr Exercise Sci & Med, Inst Biol & Life Sci, Glasgow, Lanark, ScotlandUniversidade Federal de São Paulo, Pulmonary Funct & Clin Exercise Physiol Unit, Div Resp, Dept Med,Paulista Sch Med, BR-04020050 São Paulo, BrazilWeb of Scienc

A step test to assess exercise-related oxygen desaturation in interstitial lung disease

A 6-min step test (6MST) may constitute a practical method for routinely assessing effort tolerance and exercise-related oxyhaemoglobin desaturation (ERD) in the primary care of patients with interstitial lung disease.In total, 31 patients (19 males) with idiopathic pulmonary fibrosis I and chronic hypersensitivity pneumonia were submitted, on different days, to two 6MSTs. Physiological responses were compared with those found on maximal and submaximal cycle ergometer tests at the same oxygen uptake I Chronic breathlessness was also determined, as measured by the baseline dyspnoea index (BDI).Responses to 6MST were highly reproducible: 1.3 +/- 2.0 steps(.)min(-1), +/- 5 beats(.)min(-1) (cardiac frequency), +/- 50 mL(.)min(-1) (V'O-2), +/- 7 L(.)min(-1) (minute ventilation) and +/- 2% (arterial oxygen saturation measured by pulse oximetry (Sp,O-2)). the number of steps climbed in 6 min was correlated to peak V'O-2 and the BDI. There were significant associations among the tests in relation to presence (change in Sp,O-2 between rest and exercise >= 4%) and severity (Sp,O-2 < 88%) of ERD. Four patients, however, presented ERD only in response to 6MST. Resting diffusing capacity of the lung for carbon monoxide and alveolar-arterial oxygen tension difference were the independent predictors of the number of steps climbed.A single-stage, self-paced 6-min step test provided reliable and reproducible estimates of exercise capacity and exercise-related oxyhaemoglobin desaturation in interstitial lung disease patients.UNIFESP, EPM, Dept Med,SEFICE, Div Resp,Pulm Funct & Clin Exercise Physiol Unit, BR-04020050 São Paulo, BrazilUNIFESP, EPM, Dept Med,SEFICE, Div Resp,Pulm Funct & Clin Exercise Physiol Unit, BR-04020050 São Paulo, BrazilWeb of Scienc

Expression of matrix metalloproteinases -2 and -9 in saliva from patients with chronic obstructive pulmonary disease

The increased expression of matrix metalloproteinases (MMP) is considered a key factor in the development of chronic obstructive pulmonary disease (COPD). This study aimed at assessing expression levels of MMP-2 and MMP-9 in saliva from patients with COPD, comparing them to those of healthy subjects, thus assessing the feasibility of characterizing specific biomarkers for COPD. Patients with COPD (n=16) and healthy controls (n=9) were selected; both groups submitted to spirometry and to collection of saliva samples. Saliva levels of MMP-2 and MMP-9 were determined by Western blot. MMP-2 and MMP-9 levels were significantly higher in COPD patients than in control subjects. In COPD patients, a moderate, negative correlation was found between MMP-2 concentration and forced expiatory volume at the first second (r= -0.582; p=0.014). These findings open new perspectives to study specific biomarkers in saliva to predict and monitor airway obstruction in COPD patients.O aumento da expressão das metaloproteinases da matriz extracelular (MPM) é considerado um importante fator no desenvolvimento da doença pulmonar obstrutiva crônica (DPOC). O presente estudo teve como objetivo avaliar os níveis de expressão da MPM-2 e MPM-9 na saliva de pacientes com DPOC em comparação com indivíduos saudáveis, verificando a viabilidade de usar a saliva para a caracterização de biomarcadores específicos em DPOC. Foram selecionados pacientes com DPOC (n=16) e controles saudáveis (n=9). Em ambos os grupos foram realizados teste espirométrico e obtidas amostras de saliva de cada indivíduo. Os níveis de MPM-2 e MPM-9 na saliva foram determinados pela técnica Western blot. A MPM-2 e a MPM-9 foram significativamente maiores em pacientes com DPOC do que no grupo de indivíduos saudáveis. Foi encontrada moderada correlação negativa entre a concentração de MPM-2 e o volume expiratório forçado no primeiro segundo (r= -0,582, p=0,014) em pacientes com DPOC. Estes resultados abrem novas perspectivas para o estudo específico de biomarcadores na saliva para predizer e monitorar a obstrução ao fluxo aéreo em pacientes com DPOC

Practical implementation of a quantum backtracking algorithm

In previous work, Montanaro presented a method to obtain quantum speedups for backtracking algorithms, a general meta-algorithm to solve constraint satisfaction problems (CSPs). In this work, we derive a space efficient implementation of this method. Assume that we want to solve a CSP with $m$ constraints on $n$ variables and that the union of the domains in which these variables take their value is of cardinality $d$. Then, we show that the implementation of Montanaro's backtracking algorithm can be done by using $O(n \log d)$ data qubits. We detail an implementation of the predicate associated to the CSP with an additional register of $O(\log m)$ qubits. We explicit our implementation for graph coloring and SAT problems, and present simulation results. Finally, we discuss the impact of the usage of static and dynamic variable ordering heuristics in the quantum setting.Comment: 18 pages, 10 figure

Evaluation of the effect of prednisolone on the inflammatory process and alveolar diameter in elastase- induced pulmonary emphysema in rats

This study evaluated the effect of prednisolone on acute lung inflammatory response, tissue damage and nitric oxide in elastase-induced emphysema in rats. A total of 32 male rats were divided into four groups: control and prednisolone groups received intratracheal instillation of saline; emphysema and emphysema + prednisolone groups received elastase. Prednisolone was administered in prednisolone and emphysema + prednisolone groups for 25 days by gavage. The results showed a significant increase in the alveolar airspace enlargement in the emphysema group. However, comparing control and emphysema + prednisolone groups, the treatment did not show significant reduction in the alveolar airspace enlargement. The number of leukocytes and nitric oxide level in BALF did not show statistically significant difference between groups. Despite widespread clinical use of corticosteroids in respiratory diseases, there was no direct protective effect on emphysema in treated animals, suggesting further studies related to its mechanism of action and on its clinical use in patients with emphysema.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Skeletal muscle structure and function in response to electrical stimulation in moderately impaired COPD patients

Study objective: To determine the structural and functional consequences of high-frequency neuromuscular electrical stimulation (hf-NMES) in a group of moderately impaired outpatients with chronic obstructive pulmonary disease (COPD).Design: A prospective, cross-over randomized trial.Setting: An university-based, tertiary center.Patients and materials: Seventeen patients (FEV1 = 49.6 +/- 13.4% predicted, Medical Research Council dyspnoea grades II-III) underwent 6-weeks hf-NMES (50 Hz) and sham stimulation of the quadriceps femoris in a randomized, cross-over design. Knee strength was measured by isokinetic dynamometry (peak torque) and leg muscle mass (LMM) by DEXA; in addition, median cross-sectional area (CSA) of type I and fibres and capillary-fibre ratio were evaluated in the vastus lateralis. the 6-min walking distance (6MWD) was also determined.Universidade Federal de São Paulo, UNIFESP, Pulm Funct & Clin Exercise Physiol Unit, SEFIC,Div Resp Dis,Dept Med, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Neuromusc Div, São Paulo, BrazilUniv Glasgow, Inst Biomed & Life Sci, Glasgow, Lanark, ScotlandUniversidade Federal de São Paulo, UNIFESP, Pulm Funct & Clin Exercise Physiol Unit, SEFIC,Div Resp Dis,Dept Med, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Neuromusc Div, São Paulo, BrazilWeb of Scienc