Pulmonary function and bronchial reactivity in asthmatics during low-level formaldehyde exposure

This study evaluated whether formaldehyde, at concentrations similar to those found in the indoor environment, could produce adverse effects on the lower airway of 15 asthmatic persons with documented bronchial hyperresponsiveness who were exposed for 90 min in a climate chamber to clean air containing formaldehyde vapor at levels of 0.85 mg/m3, 0.12 mg/m3, and 0.008 mg/m3. No significant changes in forced expiratory volume in 1 sec (FEV1), airway resistance (Raw), specific airway resistance (SRaw), and flow-volume curves could be detected during formaldehyde exposure. Furthermore, histamine challenge tests performed immediately after formaldehyde exposure showed no evidence of changes in bronchial reactivity. No late reactions were registered during the first 14-16 hr after exposure. The results suggest that residential levels of formaldehyde are of minor importance in the emergence of pulmonary symptoms. Discrepancies between the present study and previous data may be due to differences in environmental conditions.     

Pulmonary function changes associated with cardiomegaly in chronic heart failure

BackgroundThis study examined the influence of increased cardiac size on maximal lung volumes, forced expiratory airflows, and the diffusing capacity of the lungs in heart failure (HF) patients compared with controls.Methods and ResultsForty-one HF patients of New York Heart Association (NYHA) class: Group A = class I/II (n = 26) and Group B = class III/IV (n = 15) and an equal number matched controls (CTL) were recruited. Participants underwent echocardiography, spirometry, and posteroanterior and lateral chest radiographic evaluation (RAD) for volumetric estimation of the total thoracic cavity (TTC), diaphragm, heart, and lungs. Analysis of variance demonstrated no difference between groups for TTC volume (P = .63). RAD cardiac volumes (% TTC volume) were significantly different among all groups (P < .001). Echocardiograms determined left ventricular mass was elevated in the HF groups compared with the CTL group (P < .001) with no difference between HF groups. Lung volume (% TTC volume) was reduced as a function of disease severity (P < .001). RAD measures of cardiac volume demonstrated the strongest relationship with restrictive lung alterations (t-statistic = −5.627, P < .001 and t-statistic = −4.378, P < .001 for forced vital capacity and forced expiratory volume in 1 second, respectively).ConclusionsThese results suggest cardiac size may pose significant constraints on the lungs and likely plays a major role in the restrictive breathing patterns often reported in HF patients.     

Pulmonary function changes related to acute and chronic administration of inhaled insulin

The need for frequent insulin injections to achieve optimal glycemic control remains a major barrier to initiating and maintaining insulin therapy in diabetes. The inhaled route of insulin administration offers many potential advantages. However, there are ongoing concerns regarding the pulmonary safety of inhaled insulin. Published studies reporting pulmonary safety and data submitted to the Food and Drug Administration were reviewed. All studies were open-label, included adult subjects with type 1 and 2 diabetes, and excluded patients with underlying lung disease. Inhaled insulin was compared with subcutaneous insulin and oral agents. Inhaled insulin is associated with small, consistent reductions in lung function, primarily forced expiratory volume in 1 s (FEV(1)) and diffusion capacity for carbon monoxide (DL(CO)). The small reductions in lung function occurred early (within 12 weeks) and did not progress over time. The magnitudes of the reductions were 30-50 mL for FEV(1) and 0.5-1.0 standard units for DL(CO). Collectively, the data indicate that inhaled insulin is safe in studies with duration up to 4 years. The Food and Drug Administration requires monitoring of lung function on a regular basis.     

Pulmonary hemodynamics and lung function during chronic paraquat poisoning in sheep. Possible role of reactive oxygen species.

The purpose of this study was to establish a chronic model of paraquat-induced lung injury. To examine the role of reactive oxygen species in this form of lung injury, we measured malondialdehyde (MDA) and superoxide dismutase (SOD) activity in the lungs. Paraquat (5 mg/kg intramuscularly) caused a significant decrease in dynamic lung compliance from 128.5 +/- 9.2 to 63.3 +/- 11.8 ml/cm H2O (p less than 0.05), with a significant increase in AaPO2 3 wk after paraquat. Histologic findings in the lungs showed a gradual increase in the number of granulocytes and alveolar wall thickening with proliferation of reticular fibers and were coincident with the changes in physiology. A transient decrease in pressor responses to hypoxia was observed 1 wk after paraquat, although pulmonary hemodynamics did not change. The amount of lung MDA 3 wk after paraquat increased from the baseline value of 0.73 +/- 0.04 to 1.12 +/- 0.10 nmol/mg protein (p less than 0.05). SOD activity in the lung tissue significantly decreased from 6.47 +/- 0.20 to 4.82 +/- 0.25 U/mg protein (p less than 0.05) 1 wk after paraquat and remained at low levels for 3 wk. These findings suggest that a small dose of paraquat causes chronic lung injury characterized by granulocyte infiltration and lung fibrosis. Reactive oxygen species may play an important role in this chronic lung injury, and the inability to increase antioxidant defense may contribute to the reaction.     

Pulmonary changes after exposure to vermiculite contaminated with fibrous tremolite

Workers exposed to vermiculite contaminated with fibrous tremolite were surveyed for the presence of respiratory symptoms by questionnaire, and for pneumoconiosis by chest radiograph. Pulmonary function was measured by spirometry and single-breath carbon monoxide diffusing capacity ( DLCOsb ). Fiber exposure indexes, expressed as fiber/ml-yr, were derived for each worker from available industrial hygiene data and work histories. The estimated cumulative exposure for the work force ranged from 0.01 to 39 fiber/ml-yr. Discriminant analysis demonstrated significant correlates with shortness of breath and pleuritic chest pain to cumulative fiber exposure. The radiographic changes were limited to pleural changes and involved 4.4% of the population. Parametric and discriminant analysis demonstrated a significant correlation with radiographic changes and cumulative fiber exposure. There were no correlations between spirometry or DLCOsb and fiber exposure. Exposure to vermiculite contaminated with fibrous tremolite can cause pleural changes in occupationally exposed workers. This is supported by the previously identified 12 cases of benign pleural effusions in this working population and the association of pleural radiographic changes and pleuritic chest symptoms with cumulative fiber exposure. The lack of significant parenchymal radiographic, spirometric, and DLCOsb changes most likely reflects the low cumulative fiber exposure.     

Pulmonary function and peripheral airway disease in patients with mineral dust or fume exposure

Cigarette smoking and mineral dust exposure combined result in small airways function abnormalities difficult to distinguish from smoking effects alone. To determine if mineral dust or fume exposure in smokers results in additional changes in small airways structure and function, we studied small airways disease and pulmonary function in 25 persons (62.4 +/- 8.8 yr) with exposure to mineral dust or fume for 10 yr or more and compared them individually with control subjects without dust exposure (61.8 +/- 8.5 yr) matched for age, smoking history, and lobe resected. All subjects were patients undergoing surgical resection for isolated coin lesions. Occupational histories and measurements of lung volumes, flow rates, small airways function, diffusing capacity, and pressure-volume relationships were obtained preoperatively. Membranous bronchioles were graded for the presence and degree of mural inflammation, fibrosis, muscle, pigment, and squamous and goblet cell metaplasia. Respiratory bronchioles were similarly graded for inflammation, fibrosis, muscle, pigment, and lumenal macrophages. The dust-exposed group had increased fibrous tissue deposition and goblet cell metaplasia in the membranous bronchioles (p less than 0.05). When the exposed group was divided according to occupation into miners (n = 13) and nonminers exposed in other dusty jobs (n = 12), the pathologic changes were evident in both exposed groups. No differences in pulmonary function were seen between the 2 groups. We conclude that occupational exposure to mineral dust and fume produces structural changes in peripheral airways that are greater than those seen with smoking alone, but these changes were not associated with a greater deterioration in lung function.     

Pulmonary function at peak exercise in patients with chronic heart failure

BackgroundVarious respiratory abnormalities are associated with chronic heart failure (CHF). However, changes in inspiratory capacity (IC) and breathing pattern from rest to exercise in patients with CHF have not been thoroughly investigated in these patients.Materials and methodsSeventy seven (66 male/11 female) patients with clinical stable CHF (age: 52 ± 11 years) were studied. All the patients underwent pulmonary function tests, including measurements of IC and maximal inspiratory pressure (Pimax) at rest and then a maximal cardiopulmonary exercise testing (CPET) on a treadmill. During the CPET, IC was measured every 2 min. Pimax was measured again after the end of CPET.ResultsPercent predicted forced expiratory volume in 1 s (FEV₁) was 91 ± 12, %predicted forced vital capacity (FVC) was 92 ± 13, %FEV₁/FVC was 81 ± 4, and %predicted IC was 85 ± 18. Peak exercise IC was lower than resting (2.4 ± 0.6 vs. 2.6 ± 0.6 l, p < 0.001). Analysis of variance between Weber's groups revealed statistically significant differences in peak exercise IC (p < 0.001), V_E/V_CO2slope (p < 0.001), resting Pimax (p = 0.005) and post-exercise Pimax(p < 0.001). At rest, there was a statistically significant difference in end-tidal CO₂ (P_etco2) (p = 0.002), in breathing frequency (p = 0.004), in inspiratory time (Ti) (p = 0.04) and in total respiratory time (T_Tot) (p = 0.004) among Weber's groups. At peak exercise there was a statistically significant decrease in minute ventilation (V_E) (p < 0.001), tidal volume (V_T) (p < 0.001), respiratory cycle (V_T/T_I) (p < 0.001) and P_etco2(p < 0.001).Peak IC was correlated with peak V_O2 (r = 0.72, p < 0.001), anaerobic threshold (r = 0.71, p < 0.001), V_O2/t slope (r = 0.54, p < 0.0001), and post-exercise Pimax (r = 0.62, p < 0.001).ConclusionsIn patients with CHF, peak exercise IC is reduced in parallel with disease severity, which is probably due to respiratory muscle dysfunction.     

The effects of low-level environmental tobacco smoke exposure on pulmonary function tests in preschool children with asthma

Objectives: Though parents of children with asthma smoke, they often avoid smoking in their homes or near their children, thus limiting exposure. It is not known if such low-level environmental tobacco smoke (ETS) results in measurable exposure or affects lung function. The objectives of this study were to measure urinary cotinine in preschool children with asthma, and to examine the relationship between low-level ETS exposure and pulmonary function tests (PFTs). Methods: Preschool children with asthma were enrolled. Parents completed questionnaires on ETS exposure and asthma control, urinary cotinine concentrations were measured and PFTs were compared between subjects with and without recent ETS exposure. Results: Forty one subjects were enrolled. All parents denied smoking in their home within the last 2 weeks, but 14 (34%) parents admitted to smoking outside their homes or away from their children. Fifteen (37%; 95%CI: 23–53) of the children had urinary cotinine levels ≥1?ng/ml, of which seven (17%; 95%CI: 8–32) had levels ≥5?ng/ml. FEV₁ and FEV_0.5 were lower in subjects with a urinary cotinine level ≥5?ng/ml as compared to those with levels <1?ng/ml or between 1 and 5?ng/ml; both at baseline and after inhalation of albuterol. Five of seven subjects with urinary cotinine levels ≥5?ng/ml had FEV_0.5 less than 65% of predicted values. There were no significant differences in IOS measures. Conclusions: Despite parental denial of smoking near their children, preschool children may be exposed to ETS. Such low-level ETS exposure may affect lung function, possibly in a dose-dependent manner.     

Pulmonary function responses of older men and women to ozone exposure

The pulmonary function of 8 men and 8 women (51 to 76 years of age), all nonsmokers, was measured before and after 2-h exposures to filtered air (FA) and 0.45 ppm ozone (O3). The subjects alternated 20-min periods of rest and 20-min periods of cycle ergometer exercise at a workload predetermined to elicit a ventilatory minute ventilation (VE) of approximately 25 L/min (BTPS). Functional residual capacity (FRC) was determined pre- and post-exposure. Forced vital capacity (FVC) was determined before and after exposure, and 5 min after each exercise period. Ventilatory minute volume (VE) was measured during the last 2 min of each exercise period, and heart rate was monitored throughout each exposure. The pulmonary function data were evaluated as the percentage change from pre- to post-exposure to partially remove the effect of differences between men and women in absolute lung volume. There were no statistically significant (p greater than 0.05) differences between the responses of men and women to FA or O3 exposure. There were no significant (p greater than 0.05) changes in any variable consequent to FA exposure. Exposure to O3 induced significant (p less than 0.01) decrements in FVC, FEV1.0, and FEV3.0 at post-exposure compared to pre-exposure. Ozone exposure induced no significant (p greater than 0.05) effect on FEF25-75% or FEF75%. Men had a significantly (p less than 0.05) higher mean exercise VE than women (27.9 +/- 0.29 L vs. 25.4 +/- 0.8 L; mean +/- SD). Since the men and women had similar decrements in pulmonary function, even though the women inhaled less O3, the data suggest that women may be somewhat more responsive to O3 than men. We also compared the responses of our older subjects with those of young men and women that we studied with the same protocol, and with published results of other investigators who have studied young men and women. This comparison suggests that older individuals may be less responsive to O3 than young individuals.     

Pulmonary function changes after bronchoalveolar lavage in asthmatic patients

Pulmonary function changes were studied following bronchoalveolar lavage (BAL) in a group of mild to moderate asthmatic patients and in control subjects. After BAL significant decreases in FEV1 and FVC which were not inhibited by atropine and a consistent decline in PaO2 were seen in both groups. The magnitude of changes in these asthmatics was similar to that in control subjects.     

六味地黄方对慢性铝暴露痴呆大鼠记忆功能保护作用的研究

目的 研究六味地黄方对慢性铝暴露痴呆大鼠记忆功能的保护作用及其机制.方法 采用胃肠道慢性染铝的方法制备记忆功能障碍大鼠模型,用Morris水迷宫实验检测大鼠空间学习记忆能力,并通过对血浆中超氧化物歧化酶(SOD)、丙二醛(MDA)的测定,研究慢性铝暴露导致大鼠记忆功能损害及六味地黄方的干预机制.结果 与正常对照组相比,模型组大鼠学习记忆能力降低(P<0.01,P<0.05),血浆MDA水平增加而SOD活性减低(P<0.01,P<0.05).与慢性铝暴露模型组相比,六味地黄方能提高大鼠血浆中SOD活性,降低MDA含量,改善了慢性铝暴露大鼠学习记忆功能(P<0.01,P<0.05).结论 六味地黄方通过增加体内抗氧化酶的活性,降低慢性铝暴露导致的神经脂质过氧化反应,从而干预慢性铝暴露对大鼠记忆功能的损伤.     

Impaired exercise performance and pulmonary function in elite cyclists during low-level ozone exposure in a hot environment

We evaluated the effects of low concentrations of ozone on the exercise performance and pulmonary function of 17 top-caliber endurance cyclists under conditions simulating competition and realistic temperature (31 degrees C). Each subject was randomly exposed to filtered air (FA), 0.12 and 0.20 ppm O3 on separate days in an environmental chamber. Each subject attempted to maintain submaximal exercise on a cycle ergometer equivalent to approximately 70% of maximal oxygen consumption (VO2max) for 60 min, followed by incremented (maximal) exercise until exhaustion. During submaximal exercise, average minute ventilation (VE) (89 L/min), VO2 (51 ml/min/kg or 72% VO2max), work load (260 W), and work time (57 min) were similar across all exposures. During maximal exercise, average peak VE (150 L/min), VO2 (68 ml/min/kg), work load (382 W), and ride time (263 s) were similar between 0.12 ppm O3 and FA. However, significant reductions in peak VE (18%), VO2 (16%), tidal volume (22%), work load (8%), and ride time (30%) occurred in 0.20 ppm O3 compared with those in FA. Postexercise decrements in forced expired volume in one second (FEV1) averaged 5.6% and 21.6% in 0.12 and 0.20 ppm O3, respectively. Ozone-related symptoms were mild in 0.12 ppm O3 but intensified and probably limited maximal performance in 13 subjects in 0.20 ppm O3. Changes in carbon monoxide diffusing capacity (adjusted for alveolar volume) were not significant across exposures. Nine subjects showed histamine hyperresponsiveness (i.e., greater than 20% decrease from the control postdiluent FEV1) after exposure to 0.20 ppm O3 as compared with 1 subject in 0.12 ppm O3.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pulmonary blood volume and haemodynamic changes with legs raised in chronic lung disease patients.

STUDY OBJECTIVE--The aim was determine the early effect of a posture change from supine (S) to legs raised 30 degrees above the table plane (LR) on haemodynamics in patients with chronic lung disease. STUDY DESIGN--Right heart catheterization was performed as part of a routine evaluation. Pulmonary arterial, pulmonary wedge, right atrial, and systemic arterial pressure were monitored at rest supine and during 8 min (steady values) after LR. Pulmonary blood volume was measured by double dye dilution, at rest S and after 1 and 8 minutes LR, in 14 patients; cardiac output was measured by thermodilution in the remaining 15 subjects, during S and 1, 4, and 8 minutes LR. SUBJECTS--29 patients with chronic pulmonary disease of various types, mainly chronic bronchitis and emphysema, were studied when in a stable clinical condition, with no signs of heart failure. MEASUREMENTS AND MAIN RESULTS--Raising the legs produced a sharp increase in all the pressures measured, with a subsequent decline towards a steady value slightly higher than during S. Pulmonary blood volume increased in all patients initially, but stayed elevated only in the normocapnic patients; in the patients with hypercapnia it decreased from 1 to 8 min LR. The pulmonary blood volume change showed a significant correlation with PaCO2 (p less than 0.01), and with the VD/VT ratio (p less than 0.01). The relation between the pulmonary blood volume and the distending pressure changes from S to 1 and 8 min LR was linear in the normocapnic group, but not in the hypercapnic group, where it showed a hysteresis. CONCLUSION--In patients with chronic lung disease who are hypercapnic, the volume/pressure relation following leg raising cannot be expressed by a single distensibility coefficient.