Dynactin phosphorylation is modulated in response to cellular effectors

In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P < 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG.     

Lung diffusing capacity and exercise in subjects with previous high altitude pulmonary oedema

Subjects with a history of high-altitude pulmonary oedema (HAPE) have increased pulmonary artery pressure and more ventilation-perfusion (V'A/Q') inhomogeneity with hypoxia and exercise. We used noninvasive methods to determine whether there are differences in the pulmonary diffusing capacity for carbon monoxide (DL,CO) and cardiac output (Q') during exercise, indicative of a more restricted pulmonary vascular bed in subjects with a history of HAPE. Eight subjects with radiographically documented HAPE and five controls with good altitude tolerance had standard pulmonary function testing and were studied during exercise at 30 and 50% of normoxic maximal oxygen consumption (V'O2) at an inspiratory oxygen fraction of 0.14 and 0.21. DL,CO and Q' were measured by CO and acetylene rebreathing techniques. HAPE-resistant subjects had 35% greater functional residual capacity than HAPE-susceptible subjects. Vital capacity and total lung capacity were also 7-10% greater. There were no differences in airflow rates or resting diffusing capacity. However, DL,CO in HAPE-susceptible subjects was lower in hypoxia and with exercise, and showed less increase (32 versus 49%) with the combined stimulus of hypoxic exercise. HAPE-susceptible subjects had smaller increases in stroke volume, Q', and ventilation during exercise. The findings are consistent with lower pulmonary vasoconstriction, greater vascular capacitance and greater ventilatory responsiveness during exercise in subjects who are resistant to high-altitude pulmonary oedema. Their larger lung volumes suggest a constitutional difference in pulmonary parenchyma or vasculature, which may be a determinant of high-altitude pulmonary oedema resistance.     

Transfer of carbon monoxide during an inspiratory pause procedure in mechanically ventilated pigs

We studied the effect of forced inflation at different alveolar volumes (VA) on carbon monoxide diffusing capacity (DLCO) in anaesthetized, paralysed and mechanically ventilated healthy pigs. An inspiratory pause procedure (equivalent of the single-breath technique) consisting of a pause between an inflation and expiration, both at a constant flow rate, was used. The procedure was computer-controlled and could easily be standardized. In five pigs, VA was varied at constant inflation volume by increasing positive end-expiratory pressure (PEEP) from 2 to 10 cmH2O. Inspiratory pause time was varied from 1 to 8 s to verify whether the decay of CO was exponential. In nine pigs, DLCO was estimated at four different VA values by inflating with 15-30 ml kg-1 at 2 cmH2O PEEP. An exponential decay of CO was always obtained. With increasing VA by either an increase in PEEP or inflation volume, DLCO remained constant. Since the diffusing capacity of the pulmonary membrane is expected to increase with increasing VA, the constant DLCO may be attributed to a decrease in capillary blood volume.     

Micronodules and emphysema in coal mine dust or silica exposure: relation with lung function

The aim of this study was to investigate the respective effects of micronodules and pulmonary emphysema, detected by computed tomography (CT), on lung function in workers exposed to silica and coal mine dust. Eighty-three subjects exposed to silica (n=35) or to coal mine dust (n=48), without progressive massive fibrosis, were investigated by high-resolution and conventional CT scans to detect micronodules and to quantify pulmonary emphysema by measuring the relative area of the lung with attenuation values lower than -950 Hounsfield units. Sixty-six (54.5%) subjects had evidence of micronodules on CT scans. Smokers had micronodules more rarely than nonsmokers. Significant correlations were found between the forced expiratory volume in one second (FEV(1); % predicted) (r=-0.41, p<0.001), FEV1/vital capacity (VC) (r=-0.61, p<0.001), diffusing capacity of the lung for carbon monoxide (DL,CO) (r=-0.36, p<0.001) and the extent of emphysema. No difference was demonstrated in the linear relationships between the extent of emphysema and the pulmonary function according to the type of exposure or the presence of micronodules on CT scans. This study suggests that micronodules detected by computed tomography have no influence, by themselves, on pulmonary function and that they should only be considered as a marker of exposure.     

Role of reaction resistance in limiting carbon monoxide uptake in rabbit lungs

The contribution of reaction resistance to overall resistance to pulmonary carbon monoxide (CO) uptake [DLCO/(ThetaCO . Vc), where DLCO is lung CO diffusing capacity, ThetaCO is CO uptake conductance of erythrocytes, and Vc is pulmonary capillary blood volume] was determined in 10 anesthetized, paralyzed, and artificially ventilated rabbits. On the basis of the classical double-reciprocal equation of F. G. W. Roughton and R. E. Forster (J. Appl. Physiol. 11: 290-302, 1957), DLCO/(ThetaCO . Vc) was obtained by solving the relation DLCO/(ThetaCO . Vc) = 1 - 2/(DLNO/DLCO), where DLNO/DLCO represents the ratio between the respective single-breath diffusing capacities (DL) of nitric oxide (NO) and CO pulmonary capillary blood. The lungs of eight rabbits were inflated, starting from residual volume, by using 55 ml of indicator gas mixture (0.2% CO and 0.05% NO in nitrogen). DL values were calculated by taking the end-tidal partial pressures of CO and NO as analyzed by using a respiratory mass spectrometer. The overall value was DLCO/(ThetaCO . Vc) = 0.4 +/- 0.025 (mean +/- SD). Because of the use of O2-free indicator gas mixtures, the end-tidal O2 partial pressures were approximately 21 Torr. In one other rabbit, the application of 0.2% CO and 0.001% NO yielded DLCO/(ThetaCO . Vc) = 0.39; in the tenth rabbit, however, inspiratory volume was varied, and an identical value was found at functional residual capacity. We conclude that the contribution of reaction resistance to overall resistance to pulmonary CO uptake is independent of the inspiratory NO concentration used, including, with respect to the pertinent literature, the conclusion that in rabbits, dogs, and humans this contribution amounts to 40% when determined at functional residual capacity.     

Rapid discontinuation of hypnotics in terminal cancer patients: a prospective study

BACKGROUND: Unexplained or primary pulmonary hypertension results in an obliteration and obstruction of resistance pulmonary arteries. In these patients gas exchange is impaired and the measurement of gas transfer for carbon monoxide is usually reduced. This has been thought to represent a reduction in pulmonary alveolar capillary blood volume (Vc). A single breath test, measuring simultaneously the uptake of both nitric oxide (NO) and carbon monoxide (CO), provides a simple and practical measurement of membrane diffusion (Dm) and Vc. METHODS: A standard single breath test for the measurement of gas transfer for carbon monoxide (TLCO) was adapted to include NO (40 ppm) in the inhaled gas mixture and a breath-hold time at total lung capacity of 7.5 seconds was used. Twelve patients with primary pulmonary hypertension and 10 similar normal volunteers were studied while seated at rest. RESULTS: The patients had reduced values for TLCO and TLNO. The mean (SD) value of Dm in the patients was 36.7 (32.1) mmol/min.kPa compared with 52.8 (23.9) mmol/min.kPa in the normal subjects. Vc in the patients was 0.03 (0.03) 1 and 0.06 (0.01) 1 in the normal subjects. CONCLUSIONS: The simultaneous measurement of NO and CO uptake is possible in healthy volunteers and patients with primary hypertension. In these patients capillary blood volume is reduced compared with normal subjects.     

Salivary gland tumors after childhood radiation treatment for benign conditions of the head and neck: dose-response relationships

In this study the mechanisms were investigated whereby ACE-inhibitors improve pulmonary diffusion for carbon monoxide (DLco) in chronic heart failure. The two subcomponents of DLco are the alveolar-capillary membrane conductance (DM) and the capillary blood volume (VC). Stress failure of the membrane in chronic heart failure provides a mechanism for reduction of DM and, as a consequence, impairment of DLco. In 27 patients with chronic heart failure in NYHA functional class II to III and in 13 age- and sex-matched normal subjects, we evaluated the pulmonary function and determined DM and VC, according to the classic Roughton and Forster method, while they were given placebo, at 48 hours and 8 weeks after starting enalapril treatment (10 mg bid). ACE-inhibition had no effect in controls at both short- and mid-term. In chronic heart failure patients, a reduction in VC (likely consequence of a decrease in capillary pulmonary pressure) was the only change observed at 48 hours. At 8 weeks, DM was greatly increased even when the effective alveolar volume (VA) was accounted for (DM/VA), resulting in a significant improvement in DLco, despite a decrease in VC. The slow onset DM improvement makes it likely that the modulatory effect of ACE-inhibition on the membrane function emerges gradually, suggesting that it is likely dissociated from changes in pulmonary capillary pressure and VC. Thus, derangements of the alveolar-capillary membrane in chronic heart failure increase gas diffusion resistance; ACE-inhibition restores the diffusive properties of the membrane and gas transfer, and protects the lung when the heart is failing.     

Small airway involvement in mixed connective tissue disease

We studied pulmonary functions in 17 female patients with mixed connective tissue disease (MCTD) to detect early pulmonary involvement in this disease; in 8 of the 17 patients follow-up studies were also performed at 1.2- to 5.9-year intervals. In the first pulmonary function tests, decreases in vital capacity (VC) and diffusing capacity (DLCO) were observed in 6 (35%) and 8 (47%) patients, respectively. The ratio of forced expiratory volume in one second to VC was normal in all the patients, but pulmonary resistance and static compliance were abnormal in 6 (35%) and 10 (59%) patients, respectively. However, frequency dependence of dynamic compliance was found in all 16 patients tested. Moreover, 4 (24%) of the 17 patients had normal DLCO and DLCO-to-alveolar volume ratio (DLCO/VA). Reductions in DLCO and DLCO/VA were significantly correlated with the disease duration. These results suggest that small airway obstruction is an early and frequent indication of functional pulmonary impairment, and that impairment of alveolar gas exchange is progressive in patients with MCTD.     

Measurement of lung volume and DLCO in acute respiratory failure

We have undertaken rebreathing measurements of functional residual capacity (FRC), carbon monoxide diffusing capacity (DLCO), and diffusing coefficient (KCO) during positive pressure ventilation in 15 patients with adult respiratory distress syndrome (ARDS). Measurements of oxygenation (PaO2:FIO2 ratio) and lung injury score (LIS) were also recorded. Eight patients subsequently died (mortality of 53%). There was no significant difference in mean FRC, PaO2:FIO2, or LIS at presentation between survivors and nonsurvivors. However, both DLCO and KCO at presentation were significantly greater in survivors than nonsurvivors. In a separate study of nine patients with less severe lung injury, pulmonary capillary blood volume, derived from values of DLCO measured at two different values of FIO2, correlated with invasive pulmonary vascular resistance (PVR) measurements (r = 0.84, p < 0.01). DLCO measurements can be successfully undertaken in patients being ventilated with acute lung injury and may be a useful, noninvasive method of assessing the pulmonary circulation. The lowest values of DLCO were recorded in patients who subsequently did not survive.     

Invasive exercise testing in the evaluation of patients at high-risk for lung resection

The aim of this study was to investigate whether invasive exercise testing with gas exchange and pulmonary haemodynamic measurements could contribute to the preoperative assessment of patients with lung cancer at a high-risk for lung resection. Sixty-five patients scheduled for thoracotomy (aged 66+/-8 yrs (mean+/-SD), 64 males, forced expiratory volume in one second (FEV1) 54+/-13% predicted) were studied prospectively. High risk was defined on the basis of predicted postpneumonectomy (PPN) FEV1 and/or carbon monoxide diffusing capacity of the lung (DL,CO) <40% pred. Arterial blood gas measurements were performed in all patients at rest and during exercise. In 46 patients, pulmonary haemodynamic measurements were also performed at rest and during exercise. Predicted postoperative (PPO) values for FEV1 and DL,CO were calculated according to quantitative lung scanning and the amount of resected parenchyma. There were four postoperative deaths (6.2% mortality rate) and postoperative cardiorespiratory complications developed in 31 (47.7%) patients. Patients with respiratory complications only differed from patients without or with minimal (arrhythmia) complications in FEV1,PPO. Peak O2 uptake and haemodynamic variables were similar in both groups. The four patients who died had a lower FEV1,PPO, a lower DL,CO,PPO and a greater decrease in arterial oxygen tension during exercise, compared with the remaining patients. In conclusion, the forced expiratory volume in one second, together with the extent of parenchymal resection and perfusion of the affected lung, are useful parameters to identify patients at greatest risk of postoperative complications among those at a high-risk for lung resection. In these patients, pulmonary haemodynamic measurements appear to have no discriminatory value, whereas gas exchange measurements during exercise may help to identify patients with higher mortality risk.     

Mechanics of breathing in patients with atrial septal defect

Mechanics of breathing and pulmonary diffusing properties were investigated in 24 adult patients with atrial septal defect. The patients were divided into 3 groups according to mean pulmonary artery pressure: less than 19 mm Hg (group I), 20 to 24 mm Hg (group II), and greater than 25 mm Hg (group III). The only change observed in group I was a marked increase in diffusing capacity. Patients of group II showed not only an increase in diffusing capacity, but also an overt decrease in maximal expiratory flow at all lung volumes and at any given driving pressure. For these two groups, a highly significant inverse correlation was found between changes in diffusing and elastic lung properties (r = -0.71; P less than 0.001). In patients of group III, the expiratory flow remained clearly decreased; furthermore, lung compliance and lung volumes were sharply reduced, airway resistance was elevated, and diffusing capacity was normal. Finally, from group I to group III, the lung elastic recoil became progressively diminished at small lung volumes. These results suggest that an increased pulmonary blood volume induces an increase in diffusing capacity and a slight decrease in lung compliance. Simultaneous existance of high intravascular pressure strengthens the effects of increased pulmonary blood volume on lung mechanics and results in significant abnormalities in the lung mechanical behavior. It is postulated that these effects are due to a competition for space between vessels and airways within the bronchovascular sheaths, with a subsequent compression of small airways.     

Effects of immersion in water and changes in intrathoracic blood volume on lung function in man

1. In healthy, normal subjects simultaneous peripheral venous occlusion of all four limbs caused a small but significant increase in vital capacity (VC) and single-breath carbon monoxide transfer factor (DLCO) without significantly changing total lung capacity (TLC), residual volume (RV), pulmonary gas flow or pulmonary compliance. 2. Immersion in water to the neck resulted in a small but significant fall in VC, FEV 1.0/FVC and TLC, and a rise in DLCO, but flow/volume curves and 'closing volume' were unchanged. Peripheral venous occlusion during immersion only significantly increased VC and DLCO; pulmonary compliance and flow/volume curves did not alter significantly. 3. It is concluded that peripheral venous occlusion produces these effects by altering intrathoracic blood volume. Water immersion reduces TLC, mainly from the hydrostatic pressure, and VC is reduced from both the hydrostatic pressure and the increase in intrathoracic blood volume consequent on immersion. The increase in DLCO is due, almost entirely, to the increase in intrathoracic blood volume.     

Pulmonary complications and respiratory function changes after bone marrow transplantation in children

We prospectively assessed the frequency of pulmonary complications and the natural course of lung function after bone marrow transplantation (BMT), as well as the effect of several risk factors in a homogeneous group of 39 children who underwent allogeneic or autologous BMT for haematological malignancies between 1992 and 1995. Four patients developed pneumonia within the first 3 months and three 3-6 months after BMT. A considerable percentage of acute bronchitis was recorded throughout the follow-up. Three patients died after the 6 month visit because of pneumonia (two patients) and pulmonary aspergillosis (one patient). No patients had obstructive lung disease syndrome. At 3 months after BMT, forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and transfer factor of the lung for carbon monoxide (TL,CO) significantly decreased, but FEV1/FVC ratio and maximal expiratory flow at 25% of FVC remained unchanged, suggesting a restrictive defect with diffusion impairment. At 18 months, there was a progressive recovery in lung function, although only 11 patients had normalized. Seropositivity for cytomegalovirus had a significant effect on lung function whereas graft-versus-host disease also had an effect, although it was not statistically significant. Baseline respiratory function, type of transplant, type of conditioning regimen and respiratory infections did not significantly affect the outcome of BMT. The high frequency of severe lung function abnormalities found in this study, suggests a careful functional monitoring in all subjects undergoing bone marrow transplantation, even in the absence of respiratory symptoms.     

Cardiopulmonary adaptations to pneumonectomy in dogs. IV. Membrane diffusing capacity and capillary blood volume

Lung diffusing capacity for carbon monoxide (DLco) and its components, membrane diffusing capacity (Dmco) and capillary blood volume (Vc), as well as pulmonary blood flow (Qc), were measured at rest at several lung volumes and during treadmill exercise by a rebreathing technique in four adult dogs after right pneumonectomy (R-PNX) and in six matched control dogs (Sham) 6-12 mo after surgery. In both groups, lung inflation at rest was associated with a small increase in DLco and Dmco but not in Vc. After R-PNX, total DLco was lower by 30% at peak exercise compared with control values. When compared with DLco in a normal left lung, DLco in the remaining lung continued to increase along the normal relationship with respect to Qc up to a cardiac output equivalent to 34 l/min through both lungs of the Sham dog. There was no evidence of an upper limit of DLco being reached. The augmentation of DLco from rest to exercise was associated with corresponding increases in Dmco and Vc; after R-PNX, both Dmco and Vc continued to increase with respect to Qc along similar relationships as in control dogs without reaching an upper limit, suggesting a much larger alveolar-capillary reserve for gas exchange by diffusion than previously recognized. At higher levels of blood flow through the remaining lung, DLco was greater in adult dogs after R-PNX than after left pneumonectomy (Carlin et al. J. Appl. Physiol. 70: 135-142, 1991), suggesting that additional sources of compensation, e.g., lung growth, exist after removal of > 50% of lung.     

Iloprost as cyclic five-day infusions in the treatment of scleroderma. An open pilot study in 20 patients treated for one year

OBJECTIVE: To evaluate the safety and efficacy of cyclic intravenous iloprost therapy in diffuse or limited scleroderma. METHODS: Twenty patients, 14 women and 6 men with a mean age of 47.8 +/- 8.2 years, were given iloprost infusions for six hours a day during five consecutive days, at a rate of 0.5 to 2 ng/kg/min. The course was repeated every three months for one year. Efficacy was evaluated based on a scleroderma skin lesion score, an ischemic lesion score, a well-being self-assessment score, and lung function tests including measurement of the diffusing capacity of the lung for carbon monoxide. Safety was assessed based on adverse event collection. RESULTS: The scleroderma skin lesion and ischemic lesion scores decreased significantly over the one-year treatment period, from 37.1 +/- 16.5 to 10.2 +/- 6.9 (P < 0.001) and from 31.8 +/- 19.1 to 2.2 +/- 2.0 (P < 0.05), respectively. The well-being self-assessment score also showed a significant improvement, from 71.4 +/- 16.5 to 15.0 +/- 6.6 (P < 0.001). The diffusing capacity for carbon monoxide was decreased in 11 patients at baseline and showed a slight, non significant increase in these patients after the treatment period. No serious or persistent side effects were recorded. CONCLUSION: Cyclic intravenous iloprost therapy was associated with improvements in skin changes and in general health, as well as with a slight increase in the diffusing capacity of the lung for carbon monoxide. Our data suggest that iloprost may act on some of the pathogenetic mechanisms of scleroderma in a way that improves the course of the disease.     

A comparison of pulmonary function in male smokers and nonsmokers

Results of certain tests of pulmonary function, including a questionnaire, single-breath N2 test of closing capacity, forced expiration, and diffusing capacity were significantly different in groups of male smokers and nonsmokers. The influence of age on these smoking-related changes of pulmonary function was evaluated. The analyses indicated that (1) some tests including number of symptoms; closing capacity, i.e., closing volume plus residual volume as a percentage of total lung capacity; residual volume as a percentage of total lung capacity; Phase III of the single-breath N2 test, and steady-state diffusing capacity (ml of CO/mm Hg - min) revealed significant differences between adjusted mean smoker and nonsmoker values but did not reveal differences associated with age. (2) Tests of forced expiration (1-sec forced expiratory volume/vital capapity, reciprocal of the maximal mid-expiratory flow, maximal flow at 50 per cent of vital capacity; and moments) however, revealed differences between smoker and nonsmoker means )adjusted and unadjusted), as well as increasing smoker-nonsmoker differences with increasing age. It is suggested that the first group of tests probably measured an all-or-none response that occurred with the onset of smoking and was not affected by duration of smoking. The second group of tests probably measured the effects of continued smoking and indicated increasing abnormality associated with longer exposure (years of smoking). Test showing age-related differences between smokers and nonsmokers may reflect cummulative, irreversible changes in pulmonary function to a greater extent than test that do not.     

Lung volumes and respiratory muscle strength in adult patients with childhood- or adult-onset growth hormone deficiency: effect of 12 months' growth hormone replacement therapy

We have described impairment of the respiratory function in adult patients with childhood-onset growth hormone (GH) deficiency. The aim of the present study was to evaluate lung volumes and respiratory muscle strength in patients diagnosed as GH deficient before and after 6 and 12 months of recombinant GH treatment. Ten adults diagnosed as GH deficient in childhood, ten adults diagnosed as GH deficient in adulthood and ten healthy subjects entered the study. For each subject, evaluation of respiratory function followed the same standard approach, consisting of respiratory muscle strength assessment, record of flow-volume curves, measurement of static lung volumes and lung diffusing capacity. Childhood-onset GH-deficient patients had a significant reduction of maximal inspiratory (p < 0.01) and maximal expiratory (p < 0.05) mouth pressures. Total lung capacity, vital capacity and functional residual capacity were significantly reduced compared to healthy subjects (p < 0.05). Conversely, residual volume and diffusing lung capacity did not show any significant change. No significant change of the ratio between the percentage forced expiratory volume in 1 s and the forced vital capacity was observed. The decrease of respiratory mouth pressures was not correlated to the decrease of lung volumes. Adult-onset GH-deficient patients had only a significant reduction of maximal expiratory pressure compared to healthy subjects (p < 0.05). After 6 months of treatment no significant differences in any of the evaluated parameters were found. After 12 months of treatment patients with childhood-onset GH deficiency show a significant improvement of lung volumes (p < 0.01) and maximal respiratory mouth pressures (p < 0.005), whereas adult-onset GH-deficient patients show a significant improvement of maximal expiratory pressure (p < 0.05). In conclusion, the results of this study showed that adult patients affected with childhood-onset GH deficiency suffer from an impairment of the ventilatory function due to a reduction of lung volumes and a decrease of respiratory pressures probably due to a reduction of respiratory muscle strength. This impairment was reversed after 12 months of treatment with recombinant GH. Conversely, adult-onset GH-deficient patients had only an impairment of the maximal expiratory pressure, probably due to respiratory muscle weakness re-established after 12 months of GH therapy.     

Measurements of membrane diffusing capacity and pulmonary capillary blood volume in normal subjects and patients with mild emphysema

OBJECTIVE: To establish predicted values of membrane diffusing capacity (Dm) and pulmonary capacity blood volume (Vc), to compare the predicted values from our equations with those for Caucasians, to determine whether there are changes initially in Dm or Vc in patients with mild emphysema. PATIENTS AND METHODS: Diffusing capacity for carbon monoxide (DLco), Dm and Vc were determined in 86 normal subjects and 16 patients using the single-breath diffusing capacity for carbon monoxide (DLcosB) with two different alveolar concentrations of oxygen. RESULTS: The predicted equations are as follows. For males, DLco (ml/min/mm Hg) = 0.37H-0.19A-27.8; Dm (ml/min/mm Hg) = 0.65H-0.24A-53.7; Vc(ml) = 0.88H-78.9. For females, DLco = 0.28H-22.7; Dm = 0.59H-53.6; Vc = 66.6-0.36A. DLco and Vc are lower in Chinese than Caucasians while Dm is similar in Chinese and Caucasians. Eleven of 16 patients had a low DLco (< 80% predicted value), 12 had a low Dm and 5 had a low Vc. Eight of 12 patients with a low Dm also had a low DLco, but in 4 the DLco was normal. Nine of 12 with low Dm had a normal Vc. CONCLUSIONS: This study provides prediction equations of Dm and Vc. Chinese have a low DLco because their Vc is lower than Caucasians. The DLco and Dm are abnormal in a comparable percentage of patients. In patients with mild emphysema, the Dm becomes abnormal before the Vc.     

Pentoxifylline versus placebo in the treatment of infertility associated with minimal or mild endometriosis: a pilot randomized clinical trial

The long-term outcome of pulmonary function was evaluated in farmer's lung (FL) patients compared to representative control farmers. This is, to our knowledge, the first such study which has included a control group. Clinical examinations were conducted in 89 FL patients and 84 control farmers, matched by age, sex, and smoking habits. The mean time after the first diagnosed episode of FL was 14 yrs. The mean transfer factor of the lung for carbon monoxide (TL,CO) was on average 12% lower (p < 0.001) in FL patients compared to control farmers. In spirometry, the mean maximum expiratory flow at 50% of vital capacity (MEF50) was lower (p = 0.08) in FL patients but there were no differences in mean vital capacity (VC) or forced expiratory volume in one second (FEV1) between FL patients and control farmers. However, airway obstruction, defined as an FEV1/VC less than 88% of predicted, was more common in FL patients than in control farmers (33 versus 17%; p = 0.02). Patients who had had recurrent episodes of FL had a significantly lower mean TL,CO compared to those FL patients who had experienced only a single episode. In conclusion, impairment of the pulmonary transfer factor is the most important long-term consequence of farmer's lung. However, farmer's lung may also lead to development of airway obstruction.     

Lung tissue plasticity: morphometric analysis of anisotropic strain in liquid filled lungs

Lungs of rats were fixed at different inflation pressures (Ptp) during liquid filling with the pulmonary vessels tied to prevent vascular volume change after fixation had begun. Morphometric analysis showed that alveolar surface varied as a alveolar volume (Va) to the power 0.82, while the arithmetic mean tissue thickness varied as Va-0.2. This is interpreted as evidence for anisotropic expansion. Capillary volume (Vc) was found to increase from zero Ptp to a maximum at Ptp = 2 cm H2O then decrease as Va increased. Morphometric diffusion capacity of the membrane component increased as Va0.59 while that for whole lung (DL)paralleled the change in Vc. Alveolar capillary tissue unfolding is described as the main factor accounting for anistropic expansion of alveolar surface and for capillary configuration. The absolute values of Vc and DL were lower by 60% and 50%, respectively, compared with values obtained by standard instillation fixation methods and this is suggested could account for previous discrepancres between morphometric and physiologic estimates of DL.