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BackgroundTo have a better understanding of the mechanisms of exercise limitation in mild-to-moderate chronic obstructive pulmonary disease (COPD), we compared detailed respiratory physiology in patients with COPD and healthy age- and sex-matched controls.MethodsData were collected during the pre-treatment, patient characterization phase of a multicenter, randomized, double-blind, crossover study. Patients with COPD met Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 or 2 spirometric criteria, were symptomatic, and had evidence of gas trapping during exercise. All participants completed pulmonary function and symptom-limited incremental treadmill exercise tests.ResultsChronic activity-related dyspnea measured by Baseline Dyspnea Index was similarly increased in patients with GOLD 1 (n = 41) and 2 (n = 63) COPD compared with controls (n = 104). Plethysmographic lung volumes were increased and lung diffusing capacity was decreased in both GOLD groups. Peak oxygen uptake and work rate were reduced in both GOLD groups compared with controls (p

BackgroundTo have a better understanding of the mechanisms of exercise limitation in mild-to-moderate chronic obstructive pulmonary disease (COPD), we compared detailed respiratory physiology in patients with COPD and healthy age- and sex-matched controls.MethodsData were collected during the pre-treatment, patient characterization phase of a multicenter, randomized, double-blind, crossover study. Patients with COPD met Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 or 2 spirometric criteria, were symptomatic, and had evidence of gas trapping during exercise. All participants completed pulmonary function and symptom-limited incremental treadmill exercise tests.ResultsChronic activity-related dyspnea measured by Baseline Dyspnea Index was similarly increased in patients with GOLD 1 (n = 41) and 2 (n = 63) COPD compared with controls (n = 104). Plethysmographic lung volumes were increased and lung diffusing capacity was decreased in both GOLD groups. Peak oxygen uptake and work rate were reduced in both GOLD groups compared with controls (p

Medication for Opioid Use Disorder (MOUD) helps individuals safely withdraw from opioids. Though MOUD is effective, women stop using MOUD prematurely. The present study examined family relationships in relation to MOUD treatment acceptability among women. A convergent mixed methods research design was used in which 62 participants completed surveys and 23 participated in focus groups. Integrating qualitative data, convergence was found across two domains: 1) MOUD was perceived as acceptable and beneficial to recovery for the participants, and 2) Family support and desire for family services in MOUD treatment. Implications for MOUD treatment policy and future research are discussed. [ABSTRACT FROM AUTHOR]

Low resting inspiratory capacity (IC) and low maximal inspiratory pressure (MIP) have previously been linked to exertional dyspnea, exercise limitation, and poor survival in chronic obstructive pulmonary disease (COPD). The interaction and relative contributions of these two related variables to important clinical outcomes are unknown. The objective of the current study was to examine the interaction between resting IC and MIP (both % predicted), exertional dyspnea, exercise capacity, and long-term survival in patients with COPD. Two hundred and eighty-five patients with mild to advanced COPD completed standard lung function testing and a cycle cardiopulmonary exercise test. Multiple regression determined predictors of the exertional dyspnea-ventilation slope and peak oxygen uptake (...O2peak). Cox regression determined predictors of 10-year mortality. IC was associated with the dyspnea-ventilation slope (standardized β = -0.42, P < 0.001), whereas MIP was excluded from the regression model (P = 0.918). IC and MIP were included in the final model to predict VO2peak. However, the standardized β was greater for IC (0.43) than MIP (0.22). After adjusting for age, sex, body mass index, cardiovascular risk, airflow obstruction, and diffusing capacity, resting IC was independently associated with 10-year all-cause mortality (hazard ratio = 1.25, confidence interval5%_95% = 1.16-1.34, P < 0.001), whereas MIP was excluded from the final model (all P = 0.829). Low resting IC was consistently linked to heightened dyspnea intensity, low ...O2peak, and worse survival in COPD even after accounting for airway obstruction, inspiratory muscle strength, and diffusing capacity. These results support the use of resting IC as an important physiological biomarker closely linked to key clinical outcomes in COPD. NEW & NOTEWORTHY To our knowledge, this study is the first to show an independent association between low resting inspiratory capacity (IC) and, severe exertional dyspnea, exercise limitation, and increased mortality risk, after accounting for the severity of airway obstruction, inspiratory muscle strength, and diffusing capacity. These results support the use of resting IC as an important independent physiological biomarker closely linked to key clinical outcomes in COPD. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine whether patients with chronic obstructive lung disease (COPD) display differences in organization of the metabolic pathways and segments involved in energy supply compared with healthy control subjects. Metabolic pathway potential, based on the measurement of the maximal activity ([V.sub.max]) of representative enzymes, was assessed in tissue extracted from the vastus lateralis in seven patients with COPD (age 67 [+ or -] 4 yr; [FEV.sub.1]/FVC = 44 [+ or -] 3%, where [FEV.sub.1] is forced expiratory volume in 1 s and FVC is forced vital capacity; means [+ or -] SE) and nine healthy age-matched controls (age 68 [+ or -] 2 yr; [FEV.sub.1]/FVC = 75 [+ or -] 2%). Compared with control, the COPD patients displayed lower (P < 0.05) [V.sub.max] (mol x kg [protein.sup.-1] x [h.sup.-1]) for cytochrome c oxidase (COX; 21.2 [+ or -] 2.0 vs. 28.7 [+ or -] 2.2) and 3-hydroxyacyl-CoA dehydrogenase (HADH; 2.54 [+ or -] 0.14 vs. 3.74 [+ or -] 0.12) but not citrate synthase (CS; 2.20 [+ or -] 0.16 vs. 3.19 [+ or -] 0.5). While no differences between groups were observed in [V.sup.max] for creatine phosphokinase, phosphorylase (PHOSPH), phosphofructokinase (PFK), pyruvate kinase, and lactate dehydrogenase, hexokinase (HEX) was elevated in COPD (P < 0.05). Enzyme activity ratios were higher (P < 0.05) for HEX/CS, HEX/COX, PHOSPH/HADH and PFK/ HADH in COPD compared with control. It is concluded that COPD patients exhibit a reduced potential for both the electron transport system and fat oxidation and an increased potential for glucose phosphorylation while the potential for glycogenolysis and glycolysis remains normal. A comparison of enzyme ratios indicated greater potentials for glucose phosphorylation relative to the citric acid cycle and the electron transport chain and glycogenolysis and glycolysis relative to [beta]-oxidation. lung disease; skeletal muscle; enzymes; oxidative; glycolytic.

This study examined the effects of human pregnancy on the central chemoreflex control of breathing. Subjects were two groups (n = 11) of pregnant subjects (PG, gestational age, 36.5 [+ or -] 0.4 wk) and nonpregnant control subjects (CG), equated for mean age, body height, prepregnant body mass, parity, and aerobic fitness. All subjects performed a hyperoxic C[O.sub.2] rebreathing procedure, which includes prior hyperventilation and maintenance of iso-oxia. Resting blood gases and plasma progesterone and estradiol concentrations were measured. During rebreathing trials, end-tidal PC[O.sub.2] increased, whereas end-tidal P[O.sub.2] was maintained at a constant hyperoxic level. The point at which ventilation ([??]E) began to rise as end-tidal PC[O.sub.2] increased was identified as the central chemoreflex ventilatory recruitment threshold for C[O.sub.2] (VRTC[O.sub.2]). [??]E levels below (basal [??]E) and above (central chemoreflex sensitivity) the VRTC[O.sub.2] were determined. The VRTC[O.sub.2], was significantly lower in the PG vs. CG (40.5 [+ or -] 0.8 vs. 45.8 [+ or -] 1.6 Tow), and both basal [??]E (14.8 [+ or -] 1.1 vs. 9.3 [+ or -] 1.6 l/min) and central chemoreflex sensitivity (5.07 [+ or -] 0.74 vs. 3.16 [+ or -] 0.29 l x [min.sup.-1] x [Torr.sup.-1]) were significantly higher in the PG vs. CG. Pooled data from the two groups showed significant correlations for resting arterial PC[O.sub.2] with basal [??]E, central chemoreflex sensitivity, and the VRTC[O.sub.2]. The VRTC[O.sub.2] was also correlated with progesterone and estradiol concentrations. These data support the hypothesis that pregnancy decreases the threshold and increases the sensitivity of the central chemoreflex response to C[O.sub.2]. These changes may be due to the effects of gestational hormones on chemoreflex and/or nonchemoreflex drives to breathe. human gestation; hyperoxia; chemoreflex sensitivity; ventilatory recruitment threshold