The effect of sustained heavy exercise on the development of pulmonary edema in trained male cyclists

To determine whether intense, prolonged activity can induce transient pulmonary edema, eight highly trained male cyclists (mean +/- S.D.: age, 26.9 +/- 3.0 years; height, 179.9 +/- 5.7 cm; weight, 76.1 +/- 6.5 kg) performed a 45-min endurance cycle test (ECT). V(O2,max) was determined (4.84 +/- 0.4 L min(-1), 63.7 +/- 2.6 ml min(-1) g(-1)) and the intensity of exercise for the ECT was set at 10% below ventilatory threshold (approximately 76% V(O2, max) 300 +/- 25 W). Pre- and post-exercise pulmonary diffusion (DL(CO)) measurements and magnetic resonance imaging of the lung were made. DL(CO) and pulmonary capillary blood volume (VC) decreased 1h post-exercise by 12% (P = 0.004) and 21% (P = 0.017), respectively, but no significant change in membrane diffusing capacity (DM) was found. The magnetic resonance scans demonstrated a 9.4% increase (P = 0.043) in pulmonary extravascular water 90 min post-exercise. These data support the theory that high intensity, sustained exercise in well-trained athletes can result in transient pulmonary edema.     

Effects of prolonged exercise to exhaustion on left-ventricular function and pulmonary gas exchange

The purpose of this study was to simultaneously examine left-ventricular (LV) function and pulmonary gas exchange during prolonged constant-rate cycling in an attempt to explain the exercise-induced impairment in gas exchange. Eleven competitive cyclists rode their racing bicycles on a computerized cycle trainer at 25 W below the lactate threshold until exhaustion (exercise time = 2.51 +/- 0.86 h). LV systolic function was evaluated with two-dimensional echocardiography while arterial blood gases were used to assess pulmonary gas exchange. All variables were assessed concurrently before, during, and after exercise. LV function and cardiac output increased at the onset of exercise and were maintained until exhaustion. The alveolar-arterial P(O(2)) difference (A-a D(O(2))) increased within 15 min of the onset of exercise, was unchanged through to exhaustion, and returned to baseline 5 min post-exercise. Gas exchange was not related to cardiovascular function at the onset, or at end exercise. The results indicate that the widening A-aD(O(2)) during exercise is due to a readily reversible change in gas exchange function.     

Pulmonary diffusing capacity in pregnancy at sea level and at high altitude

The impact of pregnancy on respiratory function and whether this is influenced by living conditions, such as altitude of residence, must be determined if the management of pregnant women, particularly those with pulmonary disease is to be optimized. Pulmonary diffusing capacity, corrected for haemoglobin concentration (DL(COc)), therefore, was measured in 112 healthy Peruvian women with singleton pregnancies living at sea level and 192 living at 4300 m. At each location, 19 non-pregnant women were studied. The mean DL(COc)s of the pregnant and non-pregnant women studied at sea level were similar but lower than those of their high altitude counterparts (P<0.001, P<0.001). At high altitude, the mean DL(COc)s of women studied in the first and second trimester were similar to that of non-pregnant women, but the mean DL(COc) of pregnant women studied in the third trimester was lower than that of the non-pregnant women (P<0.01). Our results demonstrate that the effect of pregnancy on pulmonary diffusing capacity is influenced by altitude of residence.     

Evaluation of the resistance of membrane and erythrocytes to oxygen transport in pulmonary capillaries

The conductance of the diffusion pathway for oxygen in pulmonary capillaries is usually described in terms of two lumped components; the membrane and erythrocyte diffusing capacities. In this study the relative importance of these two components was investigated theoretically over a wide range of alveolar oxygen partial pressures. It was found that the membrane diffusing capacity is largely independent of the alveolar oxygen partial pressure and the erythrocyte diffusing capacity increases steeply with a decrease in alveolar oxygen partial pressure. The ratio of the resistance of the membrane to that of the erythrocytes to oxygen transport is a strong function of the alveolar oxygen partial pressure [1.5 (PAO2 = 30 mmHg); 1.0 (PAO2 = 100 mmHg); 0.5 (PAO2 = 700 mmHg)].     

The influence of training on oxygen isotope fractionation in healthy subjects

We determined the oxygen isotope fractionation in expired alveolar gas relative to inspired air (delta(A-I)) in eight young, healthy subjects at rest and at five levels of exercise up to maximal workload both before and after a training period of about 4 weeks which increased maximum oxygen uptake by about 10%. The data for delta(A-I) were used to compute the relative difference (deltaU) between the resistances of 16O18O and 16O2 for oxygen transport from the alveolar space and utilization in the mitochondria. Prior to training, deltaU decreased from 15 per thousand at rest to 5 per thousand at the highest level of exercise and after training from 12 to 5 per thousand. The difference between the results for deltaU before and after training was significant for rest (P < or = 5) but not for exercise conditions. Accordingly, we conclude that for exercise conditions the non-fractionating oxygen transport by blood flow to and the fractionating oxygen transport by diffusion in the muscles have improved by training to more or less the same degree. The decrease in deltaU in rest after training suggests that oxygen transport by diffusion in other tissues also benefits from the effects of training.     

The effect of diffusion in the respiratory tree on the alveolar amplitude response technique (AART)

Theoretical data for the alveolar amplitude response technique (AART) (J. Appl. Physiol. 41 (1976) 419-424) for assessing lung function was simulated using a single path lung model. This model takes account of stratified inhomogeneities in gas concentrations within the respiratory tree. The data was inserted into previously published parameter recovery techniques that may be used to estimate dead-space volume, alveolar volume and cardiac output. These parameter recovery techniques are based on much simpler mathematical models that do not allow stratified inhomogeneities in gas concentrations. It was found that: (i) recovered dead-space volume depended significantly on the ventilation pattern and on the distribution of volume within of the conducting airways; (ii) alveolar volume was recovered to a good degree of accuracy; and (iii) the recovered value of cardiac output was highly dependent on both the choice of inert gas and parameter recovery technique.     

五禽戏锻炼对出院过渡期慢性阻塞性肺疾病患者肺功能及运动耐量的影响

目的:观察五禽戏锻炼对出院过渡期慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者肺功能及运动耐量的临床改善效果.方法:选择2015年1至12月在佛山市南海区第四人民医院治疗随访的COPD患者,随机分为五禽戏组和对照组,对照组给予常规的随访管理及运动锻炼,五禽戏组在此基础上实施五禽戏锻炼,锻炼共持续3个月,比较两组干预前后的肺功能及运动耐量.结果:干预后五禽戏组的第1秒用力呼气容积(forced expiratory volume in one second,FEV1)、第1秒用力呼气容积/用力肺活量(FEV1/forced vital capacity,FEV1/FVC)、第1秒用力呼气容积占预计值百分比(FEV1％pred)依次为1.55 L,55.31％和55.08％,明显高于干预前的1.33 L,40.17％和43.03％及干预后对照组的1.25 L,43.55％和44.61％,差异均具有统计学意义(P＜0.05);在运动耐量方面,干预后五禽戏组的6 min步行距离(6min walk distance,6MWD)、达到无氧阈(anaerobic threshold,AT)时的运动时间及最大摄氧量依次为417.56 m,418.25 s及19.53 mL/(min.kg),明显高于干预前的332.67 m,337.14 s和15.53 mL/(min.kg)及干预后对照组的350.78 m,328.03 s和14.44 mL/(min.kg),差异均具有统计学意义(P＜0.05);同时结果还显示,对照组在FEV1/FVC及6MWD的改善差异也具有统计学意义(P＜0.05).结论:实施五禽戏锻炼有利于改善出院过渡期COPD患者的运动耐量及肺功能状态,对于提升其康复效果具有积极的推动作用.     

二维超声心动图和M型超声心动图评价左心室扩大患者左心室收缩功能的对比研究

目的评价二维超声心动图（2DE）法和M型超声心动图（ME）法测量心瓣膜病中重度二尖瓣和（或）主动脉瓣反流（VR）、扩张型心肌病（DCM）和缺血性心肌病（ICM）患者左心室收缩功能相关指标的一致性及其影响因素。方法用2DE和ME同时测量100例左心室扩大患者（VR35例、DCM32例和ICM33例）的左心室舒张末期内径（LVEDD）、左心室舒张末期容积（LVEDV）和左心室射血分数（LVEF）,分别记为LVEDD2DE、LVEDDME、LVEDV2DE、LVEDVME、LVEF2DE和LVEFME。结果①患者的LVEDD2DE与LVEDDME、LVEDV2DE与LVEDVME差异有统计学意义,LVEF2DE与LVEFME差异无统计学意义,且具有良好的相关性,r=0．869;②组内比较：3组的LVEDD2DE与LVEDDME差异均有统计学意义,VR组LVEDV2DE与LVEDVME差异无统计学意义,其他两组差异有统计学意义,3组的LVEF2DE与LVEFME差异无统计学意义;③组间比较：LVEDD2DE在DCM组与ICM组之间差异有统计学意义,在VR组与ICM组之间差异也有统计学意义,LVEDDME、LVEDV2DE。和LVEDVME有相同的结果,LVEF2DE在3组间差异均有统计学意义,LVEFME在3组间差异也均有统计学意义,2DE和ME法均得到LVEDVVR≈LVEDVDCM〉LVEDVICM和LVEFDCM〈LVEFICM〈LVEFVR的一致结论;④按LVEDD2DE分为〈80mm大左心室组和≥80mm巨大左心室组,两组的LVEDV2DE与LVEDVME差异有统计学意义,LVER2DE与LVEFME各组差异无统计学意义。结论二维法和M型超声评价VR、DCM和ICM患者左心室收缩功能的指标中LVEF一致性较好．较少受左心室形状及节段性室壁运动异常的影响。2DE和ME均得出VR组与DCM组左心室增大的程度相近．但LVEF减低的程度却不同．而ICM组左心室增大的程度小于前两组。但LVEF却较VR组减低明显。     

Effects of peripheral neuropathy on exercise capacity and quality of life in patients with chronic obstructive pulmonary diseases

Introduction

Chronic obstructive pulmonary diseases (COPD) have some systemic effects including systemic inflammation, nutritional abnormalities, skeletal muscle dysfunction, and cardiovascular, skeletal and neurological disorders. Some studies have reported the presence of peripheral neuropathy (PNP) at an incidence of 28-94% in patients with COPD. Our study aimed to identify whether PNP affects exercise performance and quality of life in COPD patients.

Material and methods

Thirty mild-very severe patients with COPD (male/female = 29/1, mean age = 64 ±10 years) and 14 normal subjects (male/female = 11/5, mean age = 61 ±8 years) were included in the present study. All subjects underwent pulmonary function testing (PFT), cardiopulmonary exercise testing, electroneuromyography and short form 36 (SF-36).

Results

Peak oxygen uptake (PeakVO₂) was lower in COPD patients (1.15 ±0.53 l/min) than healthy subjects (2.02 ±0.46 l/min) (p = 0.0001). There was no PNP in healthy subjects while 16 (53%) of the COPD patients had PNP. Forced expiratory volume in 1 s (FEV₁) and PeakVO₂ were significantly different between patients with PNP and those without (p = 0.009, p = 0.03 respectively). Quality of life of patients with PNP was lower than that of patients without PNP (p < 0.05).

Conclusions

The present study demonstrates the exercise limitation in COPD patients with PNP. Thus, presence of PNP has a poor effect on exercise capacity and quality of life in patients with COPD. Furthermore, treatment modalities for PNP can be recommended to these patients in order to improve exercise capacity and quality of life.     

The immediate effects of cortisol on pulmonary function in normals and asthmatics

We investigated short-term effects of corticosteroids on airway caliber, measured by spirometry and body plethysmography, over a period of 6 hr after an intravenous bolus of cortisol (8 mg/kg) or saline placebo was administered in a double-blind crossover format comparing 10 normal and nine asymptomatic unmedicated asthmatics. After 6 hrs isoproterenol (240 μg) was administered to compare the effects of cortisol with a β-agonist bronchodilator. Serum cortisol levels remained >100 μg/dl after cortisol and normal after placebo. Cortisol had no effect on pulmonary function except for a trend of improved flows and decreasing ratios of residual volume to total lung capacity in asthmatics that was not significant at 6 hr. Isoproterenol resulted in immediate improvement in specific conductance and flows in both groups; no interaction with cortisol was seen. We conclude that cortisol had no short-term effect on airway caliber in normals, at best a slowly evolving effect in asymptomatic unmedicated asthmatics, and no interaction with the bronchodilator effects of a maximal dose of isoproterenol in these groups.     

Effects of sevoflurane and propofol on right ventricular function and pulmonary circulation in patients undergone esophagectomy

Object: Sevoflurane and propofol are both widely used in clinical anesthesia. The aim of this study is to compare the effects of sevoflurane and propofol on right ventricular function and pulmonary circulation in patients receiving esophagectomy. Methods: Forty adult patients undergoing an elective open-chest thoracotomy for esophagectomy were randomized to receive either propofol (n=20) or sevoflurane (n=20) as the main anesthetic agent. The study was performed in Changzheng Hospital. Hemodynamic data were recorded at specific intervals: before the surgery (T0), BIS values reaching 40 after anesthesia induction (T1), two-lung ventilation (T2), ten minutes after one-lung ventilation (T3), the end of the operation (T4) using PiCCO₂ and Swan-Ganz catheter. Results: CI, RVEF, RVSWI and RVEDVI were significantly smaller in propofol group than those in sevoflurane group throughout the surgery (P<0.05). However, SVRI was significantly greater in propofol group than that in sevoflurane group (P<0.05). Compared with the patients in propofol group, the patients who received sevoflurane had a greater reduction in OI and increase in Os/Ot (P<0.05). And, PVRI was significantly smaller in sevoflurane group than in propofol group (P<0.05). Conclusion: Anesthesia with sevoflurane preserved better right ventricular function than propofol in patients receiving esophagectomy. However, propofol improved oxygenation and shunt fraction during one-lung ventilation compared with sevoflurane anesthesia. To have the best effect, anesthesiologists can choose the two anesthetics flexibly according to the monitoring results.     

多索茶碱与噻托溴铵粉联合治疗对慢阻肺患者肺功能影响的临床观察

目的：探讨多索茶碱与噻托溴铵粉联合治疗慢阻肺对肺功能的影响。方法：选取2009年7月至2012年11月在我院进行治疗慢阻肺患者114例,随机分为观察组和对照组,观察组采用多索茶碱与噻托溴铵粉联合治疗,对照组给予多索茶碱单独治疗,比较疗效。结果：观察组有效率为96.49%,对照组有效率为70.18%;治疗后,观察组与对照组的社会活动、日常生活、焦虑、抑郁评分以及总分、FEV1、FVC、FEV1/FVC水平差异显著（P〈0.05）。结论：多索茶碱与噻托溴铵粉联合治疗慢阻肺,可显著改善患者肺功能,提高治疗疗效,提高患者生活质量,值得临床运用。     

The effect of hormone replacement therapy on diastolic left ventricular function in hypertensive and normotensive postmenopausal women

Objectives: To evaluate the effect of hormone replacement therapy (HRT) on left ventricular diastolic function in a group of hypertensive and normotensive postmenopausal women. Methods: Left ventricular diastolic function at rest was evaluated by M-mode, two-dimensional and Doppler echocardiography in 19 postmenopausal women with normal blood pressure and 11 postmenopausal women with mild hypertension, before treatment and during 12 months of HRT. Transdermal estradiol was used in women with a surgical menopause and a sequential regimen of transdermal estradiol and peroral medroxyprogesterone acetate in women with a spontaneous menopause. The parameters assessed were: body mass index, heart rate, ejection fraction of the left ventricle (EF), septal (SW) and posterior wall (PW) dimensions, left ventricular end-systolic (LVsd) and end-diastolic (LVdd) dimensions and volumes (ESV, EDV), total diastolic time (DT), duration of the early (Ei) and of the late (Ai) filling phase, peak velocity of the early (E) and late mitral flow (A), A/E velocity ratio and systolic and diastolic blood pressure. Quantitative data were analyzed using unpaired t-test, MANOVA and multiple regression analysis where appropriate. Results: Hypertensive postmenopausal women had significantly higher SW (P<0.05), PW (P<0.05), A/E (P<0.05) and A (P<0.001) than normotensive postmenopausal women, before therapy. After 12 months of HRT a significant decrease in SW, PW, LVsd, ESV and increase in EF, DT, Ei and E was observed in both hypertensive and normotensive postmenopausal women. Heart rate slowed and systolic pressure decreased significantly only in normotensive postmenopausal women on HRT. Conclusion: HRT of 12 months' duration does not deteriorate left ventricular diastolic function of both hypertensive and normotensive postmenopausal women. Improvement in some parameters of diastolic function could be partially explained by the decrease in heart rate and systolic pressure, induced by therapy.     

长期应用巯甲丙脯酸对心肌梗塞大鼠心脏构筑与左室功能的影响

为探讨心肌梗塞(MI)后长期应用巯甲丙脯酸(Cap)对心脏构筑与左室功能的影响,MI鼠与假手术鼠自术后第三天通过饮水给予Cap五周。结果表明,Cap可明显降低MI鼠与假手术鼠的左室重量与体重的比值,并使两组大鼠尤其是MI鼠每核平均心肌细胞体积明显缩小,心肌细胞长度与直径也相应变小,但对两组心室构型的影响不同,主要表现为给药MI鼠左室腔容积明显缩小。Cap对MI鼠基础状态和容量负荷下的心脏指数(CI)无明显影响。但由于给药后左室腔半径缩小,LVEDP降低,提示其射血分数增加。表明MI后长期应用Cap虽可明显抑制代偿性心肌肥大,但由于左室腔缩小及负荷降低,心功能反而有所改善。     

柳胺苄心定对急性心肌梗塞家兔心肌血流量梗死范围及左室功能的影响

本文观察了兼有α_1受体阻断作用的β受体阻断剂柳胺苄心定(labetalol,简称Lab)对急性心肌梗塞家兔心肌血流量(放射性微球法),梗死范围及左室功能的影响,并与心得安比较。结果表明:小剂量Lab(1mg/kg)主要显示β受体阻断效应,它能减慢心率,降低心肌耗氧量,降低非梗死区心肌血流量,缩小梗死范围,其效应与心得安相似,且能改善左室舒缩功能;大剂量Lab(5mg/kg),能同时阻断α_1和β受体,它能降低动脉血压,相对增加各区心肌血流量,显著减少心肌耗氧量,缩小梗死范围。结果提示:在急性心肌梗塞治疗中,同时阻断α_1和β受体较单纯阻断β受体优越。     

Why savannah monitor lizards hyperventilate during activity: a comparison of model predictions and experimental data

The functional and structural factors that limit maximal oxygen uptake (VO2 max) in lizards are not completely understood. Using an integrative model describing the interactive nature of the individual oxygen transport conductances, we performed an analysis of the oxygen transport system in the highly aerobic lizard Varanus exanthematicus with specific reference to the sensitivity of VO2 max to potential limitations in the ventilatory system. Our analysis predicts that DLO2 must increase more than three-fold at VO2 max and even with this increase in DLO2 , the VO2 max may be sensitive to factors that alter lung ventilation and/or lower lung PO2. To test the predictions of the model analysis, we experimentally determined the effects of reducing inspired O2 on VO2 max during treadmill exercise. We conclude from both our theoretical and experimental analyses that V. exanthematicus operates near the functional limits of its lung.     

The impact of breastfeeding on lung development and function: a systematic review

With the global trend of increasing asthma and allergic disorders there is strong interest regarding early life nutrition as a potentially modifiable risk factor for lung disease. This systematic review includes 10 studies that assessed the effect of breastfeeding on lung growth and function. The review found breastfeeding to be beneficial for lung function, with the most consistent effect on increased forced vital capacity. There was no clear evidence that the relationship between breastfeeding and lung function was mediated through other factors. Furthermore, the findings from the few studies that investigated if maternal asthma modified the effect of breastfeeding on lung function were inconsistent. Further research is needed to determine the specific details such as duration and type (exclusive vs partial) of breastfeeding that leads to improved lung function.     

The dual effects of ouabain on45Ca2+ transport and contractility in adult rat ventricular myocytes

We used isolated ventricular myocytes to study⁴⁵Ca²⁺ transport in the presence of three concentrations of ouabain (10 nM, 1 M, and 100 M) in Tyrode solution containing 1 mM CaCl₂. The cells were quiescent and during⁴⁵Ca²⁺ uptake and⁴⁵Ca²⁺ efflux experiments 10 nM ouabain decreased Ca²⁺ content, 1 M, didn't change it appreciably, and 100 M increased it significantly. Qualitatively, the same results were obtained at 22°C and 35°C. Ouabain did not significantly affect the electrical activity of isolated, electrically stimulated myocytes, but it increased the amplitude of shortenings of these myocytes in a dose-dependent manner. Thus, the positive inotropic effect of ouabain at therapeutic doses (10 nM) occurs in spite of decreased Ca²⁺ content, while at high toxic doses the positive inotropic effect is accompanied by an increment in Ca²⁺ content. These data support the hypothesis that the mechanisms of positive inotropy of ouabain are different at therapeutic and toxic concentrations of this drug. Finally, our study demonstrates that the effects of low doses of ouabain are independent of the release of endogenous catecholamines.     

No effect of trans sodium crocetinate on maximal O(2) conductance or V(O(2),max) in moderate hypoxia

The lumped parameter describing skeletal muscle diffusional conductance for O(2), DM(O(2)), reflects all of the resistances for O(2) in moving from red cell to muscle fiber mitochondria. The purpose of our study was to determine if the carotenoid compound, trans sodium crocetinate (TSC), which has been reported to increase the diffusivity of O(2) in plasma, improves DM(O(2)) and thus, V(O(2),max) in maximally contracting in situ skeletal muscle. V(O(2),max) was measured in the isolated perfused canine gastrocnemius (n=5) during 3 min of isometric tetanic contractions at 1 Hz, while the animal was breathing 12% O(2) (PA(O(2))=32+/-2 Torr, mean+/-S.E.) under two experimental conditions. The first was a control contraction period and the second (following 60 min recovery) was performed within 5 min after infusion of a 0.1 mg x ml(-1) solution of TSC (total dose 100 microg kg(-1)). There were no significant differences in convective O(2) delivery (11.9+/-2.3 vs. 12.1+/-2.2 ml x min(-1) x 100 g(-1)), V(O(2),max) (9.5+/-1.5 vs. 9.6+/-1.5 ml x min(-1) x 100 g(-1)) or calculated DM(O(2)) (0.37+/-0.03 vs. 0.37+/-0.04 ml x min(-1) x 100 g(-1) x Torr(-1)) between contraction periods. As such, our results show that TSC does not improve performance in maximally contracting canine gastrocnemius muscle in situ under moderately hypoxic conditions, suggesting either that TSC in this situation does not increase plasma O(2) diffusivity or that this step in O(2) diffusion from red cell to myocyte does not constrain DM(O(2)).