Use of submaximal inhalation and spirometry to assess the effects of ozone exposure

Spirometric measures of airway obstruction are strongly influenced by the neurally mediated reduction in total lung capacity that accompanies ozone exposure. This study was conducted to evaluate a method for quantifying the effects of performing spirometry from a reduced inspiratory position on measures of airway obstruction, and to apply the method to published ozone-response data. Nineteen healthy, nonsmoking adults, 18-30 yr of age, each performed 17 forced expiratory maneuvers from inspiratory volumes that ranged from functional residual capacity to total lung capacity. In general, measures of airway obstruction were related strongly to total expired volume, and approximately 80% of the ozone-induced decrease in forced expiratory volume in 1 s (FEV1.0) resulted from the reduction in forced vital capacity. Results indicated that, for young, healthy, nonsmoking adults, spirometric values from maneuvers conducted from reduced inspiratory positions can be predicted accurately and precisely in the unexposed state, allowing interpretation of measures of ozone-induced airway obstruction.

Inhalation and deposition of nebulized sodium cromoglycate in two different particle size distributions in children with asthma

The relative deposition of two inhaled droplet size distributions of sodium cromoglycate produced by a Hudson Updraft II nebulizer was evaluated, using a setup modified from the proposed Comité Européen Normalisé (CEN) standard prEN 13544-1. The modified setup comprised an Andersen 296 impactor and a Spira Electro 2 dosimeter. The setup was characterized prior to use in children with sodium cromoglycate (SCG) and sodium fluoride as tracer aerosol. The main in vivo study was designed to allow nine children with a mean age of 10 years to inhale SCG aerosol at two different relative humidities (RH), a high RH (> 90%) and a low RH (13%), which in turn resulted in two different droplet size distributions. The nebulizer/dosimeter was set to provide 1-sec nebulization during 50 inhalations. Throughout the exposures, the children were instructed to inhale in a consistent manner with target tidal volumes (0.5 L) and inhalation flows (0.4 L/sec). Blood samples were taken at predefined time intervals, and the area under the curve (AUC) was calculated. A lung deposition program, TGLD2, was used to calculate the expected deposition, using the droplet sizes and inhalation parameters obtained during in vivo exposures. The in vivo monitoring of droplet size distribution during the exposure showed that the low, intermediate (room air), and high RHs gave a mean droplet size distribution with a mass median aerosol diameter (MMAD) of 1.2, 1.7, and 2.0 microm, respectively. The average tidal volume over all exposures was 0.51 +/- 0.12 L. The total deposition fraction was 33.4% of the estimated nebulizer output. A correlation was found between tidal volume and the calculated deposited fraction. The results indicate that there is a difference in total deposition, depending on the size of the droplet size distribution, with the larger droplet size distribution (MMAD, 2.0 microm) having a higher total deposition than the smaller droplet size distribution (MMAD, 1.2 microm). The deposition results were in good agreement with the deposition fractions estimated using the TGLD2 software for the inhalation parameters found in the study. The obtained study results can arise from differences in regional deposition, but may also be explained by differences in extrathoracic deposition.

Pulmonary function changes and immunomodulation of cytokine expression by zafirlukast after sensitization and allergen challenge in brown Norway rats

BACKGROUND

The cysteinyl leukotrienes are known important mediators in bronchial asthma.

OBJECTIVE

Our purpose was to evaluate the effect of zafirlukast on the late-phase reaction, bronchial hyper-responsiveness (BHR) and T cell-related cytokine mRNA expression in ovalbumin (OA)-sensitized brown Norway rats (BNRs).

METHODS

Thirty BNRs were equally divided into three groups. Group I and II animals were sensitized and then provoked with OA. Zafirlukast was given intraperitoneally (i.p.) to group I animals prior to provocation. Group II animals received i.p. normal saline. Group III animals (controls) were not sensitized and breathed aerosolized saline. After OA provocation, the animals were anaesthetized. Pulmonary function tests (PFT) were performed at baseline and after varying doses of acetylcholine. Thereafter, bronchoalveolar lavage (BAL) was performed and the lungs were examined histologically. Total RNA was extracted from lung tissue and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using primers for IL-2, IL-4, IL-5, IL-6, IL-10, TNF-alpha, IFN-gamma, iNOS and beta-actin.

RESULTS

Group II OA-treated BNRs had worse PFT results, more severe bronchoconstriction in response to acetylcholine, and more severe inflammation in lung tissue than the other two groups. Group II had higher IL-2, IL-4, IL-10 and IFN-gamma cytokine levels in BAL fluid and higher IL-2, IL-4, IL-5, IL-6, IL-10, IFN-gamma, TNF-alpha and iNOS mRNA levels when compared with group I.

CONCLUSION

Zafirlukast is effective in preventing late-phase bronchoconstriction and BHR, reducing inflammatory response, and decreasing IL-2, IL-4, IL-5, IL-6, IL-10 and IFN-gamma and iNOS mRNA expression.

Response of lung volumes to inhaled salbutamol in a large population of patients with severe hyperinflation

OBJECTIVES

Current criteria use FEV(1) to assess bronchodilator responsiveness, despite its insensitivity and inability to predict improvement in symptoms or exercise tolerance. Response in lung volumes remains largely unexplored even though volume parameters, such as inspiratory capacity (IC), closely correlate with functional improvements. Therefore, we assessed the response of lung volumes (i.e., by IC, total lung capacity [TLC], functional residual capacity [FRC], residual volume [RV], and FVC) to salbutamol and the relationship of these changes to improvements in the spirometry in these patients.

DESIGN

A retrospective review of data extracted from a large database of patients who were undergoing spirometry and static lung volume measurements before and after the administration of 200 microg salbutamol.

PATIENTS

Patients with an FEV(1)/FVC ratio of < 85% of predicted values were defined as being severely hyperinflated (SH) if TLC was > 133% of predicted and as being moderately hyperinflated (MH) if TLC was 115 to 133% of predicted.

RESULTS

Two hundred eighty-one SH patients and 676 MH patients were identified. Salbutamol significantly reduced the mean (+/- SEM) TLC (SH patients, 222 +/- 23 mL; MH patients, 150 +/- 10 mL; p < 0.001), FRC (SH patients, 442 +/- 26 mL; MH patients, 260 +/- 39 mL; p < 0.001), and RV (SH patients, 510 +/- 28 mL; MH patients, 300 +/- 14 mL; p < 0.001) and increased both the IC (SH patients, 220 +/- 15 mL; MH patients, 110 +/- 11 mL; p < 0.001) and FVC (SH patients, 336 +/- 21 mL; MH patients, 204 +/- 13 mL; p < 0.001). FEV(1) improved in a minority of patients (SH patients, 33%; MH patients, 26%), but if lung volume measurements are also considered, the overall bronchodilator response may improve to up to 76% of the SH group and up to 62% of the MH group. Changes in volumes correlated poorly with changes in maximal airflows.

CONCLUSIONS

Bronchodilators reduce hyperinflation. Measurements of lung volumes before and after bronchodilators add sensitivity when examining for bronchodilator responsiveness.

Changes in pulmonary hyperinflation and bronchial hyperresponsiveness following treatment with lansoprazole in children with cystic fibrosis

SUMMARY. In this prospective open study of 14 children with cystic fibrosis (CF), we evaluated the effect of 1 year adjuvant therapy with lansoprazole, a proton pump inhibitor (PPI), on growth, fecal fat loss, body composition and lung function. Only stable patients with pancreatic insufficiency were included, and their data were compared to those of a large Dutch pediatric normal reference population. During the use of the PPI, mean weight and height did not change significantly, while body mass index improved (P < 0.05). An immediate significant and persistent reduction of fecal acid steatocrit (P < 0.05) was demonstrated. Compared to normal Dutch children, the CF patients showed significantly decreased standard deviation scores (SDS) for total body fat (TBF, -0.966) and fat-free mass (FFM, -1.826). Under lansoprazole, TBF improved significantly (P < 0.05), while mean FFM remained unchanged. A significant improvement in total lung capacity (P < 0.05), residual volume (P = 0.055), and maximal inspiratory mouth pressure (P = 0.002) was also demonstrated. Hyperinflation tended to decrease during the use of a PPI. Daily recordings of peak expiratory flow (PEF) showed a maximal diurnal variability of 28% of recent best PEF and minimal morning PEF of 72% of recent best PEF, confirming that bronchial hyperresponsiveness is increased in CF. We conclude that adjuvant therapy with lansoprazole in young CF patients with persistent fat malabsorption, decreased fat losses and improved total body fat. Lung hyperinflation decreased, which may partly explain the improvement in inspiratory muscle performance. The simultaneous improvements in body composition and lung hyperinflation suggest a relationship between these two parameters. Further research is necessary to confirm such a relationship and to elucidate the mechanisms involved.

Capsaicin pre- and post-treatment on rat monocrotaline pneumotoxicity

Monocrotaline (MCT) produces respiratory dysfunction, pulmonary hypertension (PH), and right ventricular hypertrophy (RVH) in rats. Tachykinins, such as substance P (SP) and neurokinin A (NKA), may mediate these effects. The purpose of this study was to investigate the length of tachykinin depletion (via capsaicin treatment) is needed to prevent (or attenuate) PH and/or RVH. Six groups of rats were injected subcutaneously with saline (3 ml/kg); capsaicin followed by saline or MCT (60 mg/kg); or MCT followed 7, 11, or 14 days later by capsaicin. Capsaicin (cumulative dose, 500 mg/kg) was given over a period of 4-5 days. Respiratory function, pulmonary vascular parameters, lung tachykinin levels, and tracheal neutral endopeptidase (NEP) activity were measured 21 days after MCT or saline injection. Capsaicin significantly decreased lung levels of SP but not NKA. Both capsaicin pretreatment and posttreatment blocked the following MCT-induced alterations: increases in lung SP and airway constriction; decreases in tracheal NEP activity and dynamic respiratory compliance. Administration of capsaicin before or 7 days after MCT blocked MCT-induced PH and RVH. The above data suggest that the early tachykinin-mediated airway dysfunction requires only transient elevated tachykinins, while progression of late tachykinin-mediated effects (PH and RVH) requires elevated tachykinins for more than one week.

Measurement of total lung deposition of inhaled ultrafine particles in healthy men and women

Ultrafine particles (< 0.10 microm in diameter) are present in great number in polluted urban air, thus posing a potential health risk. In this study, the total deposition fraction (TDF) of ultrafine aerosols with a narrow size distribution (number median diameter NMD = 0.04-0.1 microm and geometric standard deviation sigma(g) = approximately 1.3) was measured in a group of young healthy adults (11 men and 11 women). TDF was obtained with 6 different breathing patterns: tidal volume (V(t)) of 500 ml at respiratory flow rates (Q) of 150 and 250 ml/s; V(t) = 750 ml at Q of 250 and 375 ml/s; and V(t) = 1 L at Q of 250 and 500 ml/s. Aerosols were monitored continuously by a modified condensation nuclei counter while subjects were inhaling them with prescribed breathing patterns. For a given breathing pattern, TDF increased as particle size decreased, regardless of the breathing pattern used. For example, with V(t) = 500 ml and Q = 250 ml/s, TDF (mean +/- SD) was 0.26 +/-.04, 0.30 +/-. 05, 0.35 +/-.05, and 0.44 +/-.07 for NMD = 0.10, 0.08, 0.06, and 0. 04 microm, respectively. For a given NMD, TDF increased with an increase in V(t) and a decrease in Q. TDF was greater for women than men at NMD = 0.04 microm within all breathing patterns used (p <.05), but the difference was smaller or negligible for larger sized particles. The results suggest that the TDF of ultrafine particles increases with a decrease of particle size and with breathing patterns of longer respiratory time, a pattern that is consistent with diffusion deposition of ultrafine particles. The results also suggest that there is a differential lung dose of ultrafine particles and thus there may be a differential health risk for men versus women.

Ozone adaptation in mice and its association with ascorbic acid in the lung

We have previously shown that ozone (O(3)) adaptation occurred in rats after daily exposure to an "urban-type" concentration. The adaptation was positively associated with an excess of ascorbic acid (AA) in bronchoalveolar lavage fluid (BALF), suggesting that AA may play a role in the adaptation mechanism. This relationship was not seen at higher and more toxic exposures. The present work exposed mice to low and high levels of O(3) to see if the adaptation-AA relationship is common among rodent species. Male CD-1 mice were studied during repeated 6-h/day exposures to 0.0 or 0.25 ppm O(3) for 10 days and 10 days of recovery in air (experiment 1) and to 0.0, 0.5, or 1.0 ppm O(3) for 5 days (experiment 2). Approximately 20 h after each daily exposure, groups of mice were randomly selected from each concentration type and examined for patterns of response. They were anesthetized (urethane, ip), intubated, and the lungs were lavaged with 37 degrees C saline. BALF was assayed for cells, cell differential, protein, albumin, lactate dehydrogenase, lysozymes, N-acetyl-beta-D-glucosaminidase, gamma-glutamyl transferase, uric acid, glutathione, and AA. Body weight and total lung capacity were also measured. Mice from experiment 1 (10/exposure) were tested for adaptation on day 12 by challenging them with 1.0 ppm O(3) for 6 h and collecting BALF 20 h later. In experiment 2, adaptation was assessed by evaluating the attenuation in response to continued exposure. There was only minimal response to the daily O(3) exposures in experiment 1 except for AA, which was significantly increased in BALF by day 3 and remained elevated well into the recovery period. The O(3)-preexposed mice demonstrated adaptation when compared to their O(3)-naive counterparts. Daily exposure to 1. 0 ppm O(3) in experiment 2 caused weight loss and changes in BALF consistent with toxicity, and neither adaptation nor an excess quantity of AA was seen. The findings in mice were in agreement with those seen in rats and suggest that there may be a common O(3) adaptation mechanism among rodents that involves the regulation of AA in lung lining fluid.

Evaluation of diffusing capacity in patients with a restrictive lung disease

BACKGROUND

In healthy volunteers, the single-breath diffusing capacity of the lung for carbon monoxide (DLCO) decreases and DLCO normalized per liter alveolar volume (VA; DLCO/VA) increases if VA is decreased. We hypothesized that comparison of DLCO/VA with its predicted value at predicted total lung capacity (TLC) will result in an underestimation of the diffusion disorder in patients with a restrictive lung disease, if a similar relationship exists between DLCO/VA and lung volume as found in healthy volunteers.

OBJECTIVE

To test this hypothesis, we studied total gas transfer DLCO and DLCO/VA as functions of VA in patients who developed a restrictive lung disease and a diffusion disorder in a short period of time.

DESIGN

An observational survey.

SETTING

Pulmonary function department.

PATIENTS

Thirteen patients without any initial pulmonary pathology who developed the mentioned pulmonary pathology due to bleomycin treatment.

INTERVENTIONS

Bleomycin treatment.

MEASUREMENTS AND RESULTS

We performed the single-breath test at various VA levels before, during, and after bleomycin treatment. In the majority of the patients, the DLCO vs VA relationship remained parabolic, but shifted downwards during therapy. Therefore, the linear DLCO/VA vs VA relationship shifted downwards, while the negative slope was not changed, indicating the development of a decreased gas transfer. Six patients also developed a volume restriction.

CONCLUSIONS

The agreement of the data with the hypothesis increased its probability. Consequently, to evaluate a diffusion disorder, DLCO/VA at a lower actual TLC of patients with a lung restriction should be compared to a reference DLCO/VA at a lung volume equal to the actual TLC.

Mediators in hyperpnea-induced bronchoconstriction of guinea pigs

Both tachykinins and leukotrienes (LTs) have been demonstrated to be the mediators for hyperpnea-induced bronchoconstriction (HIB) of guinea pigs. We tested the hypothesis that leukotrienes modulate HIB indirectly by triggering tachykinin release. Ninety nine young guinea pigs were divided into four groups: control; LTC4; FPL 55712 (a LT receptor antagonist); and MK-886 (an inhibitor of LT synthesis). Each animal was anesthetized, cannulated, paralyzed, and artificially ventilated. The protocol included the baseline, hyperpnea, and recovery periods. Thus, animals in each group were further divided into three subgroups: baseline; recovery-3 min; and recovery-8 min. We measured dynamic respiratory compliance (Crs), forced expiratory volume in 0.1 s (FEV0.1) and maximal expiratory flow at 30% total lung capacity (Vmax30), as well as determined substance P (SP) and LT levels in plasma and bronchoalveolar lavage (BAL) during either the baseline or the recovery (3 or 8 min) period. Hyperpnea caused decreases in Crs, FEV0.1 and Vmax30, indicating HIB, in the control group at 3 min and 8 min of the recovery period. Both FPL 55712 and MK-886 significantly attenuated HIB. In the control group, hyperpnea caused significant increases in SP and LT levels in both plasma and BAL. These increases in SP levels were significantly suppressed, however, by FPL 55712 and MK-886. Compared to the control group, infusion of LTC4 did not significantly alter either HIB, SP or LT levels in most cases. An additional group of 24 animals treated with neurokinin-2 receptor antagonist, SR 48968, demonstrated that SR 48968 significantly suppressed hyperpnea-induced increases in plasma, but not in BAL, LT levels. Since FPL 55712 and MK-886 first suppress LT activities, these results suggest that suppressed LT activities attenuate HIB indirectly via reducing tachykinin release.

A preliminary study of long-term treatment with interferon gamma-1b and low-dose prednisolone in patients with idiopathic pulmonary fibrosis

BACKGROUND AND METHODS

Patients with idiopathic pulmonary fibrosis have progressive scarring of the lung and usually die within four to five years after symptoms develop. Treatment with oral glucocorticoids is often ineffective. We conducted an open, randomized trial of treatment with a combination of interferon gamma-1b, which has antifibrotic properties, and an oral glucocorticoid. We studied 18 patients with idiopathic pulmonary fibrosis who had not had responses to glucocorticoids or other immunosuppressive agents. Nine patients were treated for 12 months with oral prednisolone alone (7.5 mg daily, which could be increased to 25 to 50 mg daily), and nine with a combination of 200 microg of interferon gamma-1b (given three times per week subcutaneously) and 7.5 mg of prednisolone (given once a day).

RESULTS

All the patients completed the study. Lung function deteriorated in all nine patients in the group given prednisolone alone: total lung capacity decreased from a mean (+/-SD) of 66+/-8 percent of the predicted value at base line to 62+/-6 percent at 12 months. In contrast, in the group receiving interferon gamma-1b plus prednisolone, total lung capacity increased (from 70+/-6 percent of the predicted value at base line to 79+/-12 percent at 12 months, P<0.001 for the difference between the groups). In the group that received interferon gamma-1b plus prednisolone, the partial pressure of arterial oxygen at rest increased from 65+/-9 mm Hg at base line to 76+/-8 mm Hg at 12 months, whereas in the group that received prednisolone alone it decreased from 65+/-6 to 62+/-4 mm Hg (P<0.001 for the difference in the change from baseline values between the two groups); on maximal exertion, the value increased from 55+/-6 to 65+/-8 mm Hg in the group that received combined treatment and decreased from 55+/-6 mm Hg to 52+/-5 mm Hg in the group given prednisolone alone (P<0.001). The side effects of interferon gamma-1b, such as fever, chills, and muscle pain, subsided within the first 9 to 12 weeks.

CONCLUSIONS

In a preliminary study, 12 months of treatment with interferon gamma-1b plus prednisolone was associated with substantial improvements in the condition of patients with idiopathic pulmonary fibrosis who had had no response to glucocorticoids.

Decline in lung function in lymphangioleiomyomatosis: relation to menopause and progesterone treatment

The progression of lymphangioleiomyomatosis, a rare lung disease in women, is thought to be influenced by hormonal factors. We studied the rate of decline in FEV(1) and carbon monoxide transfer factor (TL(CO)) in a national cohort of patients with lymphangioleiomyomatosis in the United Kingdom and its relation to two factors that might influence the disease, menopausal status and progesterone treatment. We used retrospective data from hospital notes, and of the 50 patients identified 43 had suitable lung function data spanning at least 3 mo. Mean (SD) annual decline in FEV(1) was 118 (142) ml for all patients, and these figures changed little when only data spanning at least 2 and 3 yr were analyzed. There was considerable variation in the rate of decline between subjects, however, and although it tended to be less among postmenopausal women and those receiving progesterone, patient numbers were smaller and the findings were not significant. There was a significant reduction in decline in TL(CO) in premenopausal patients receiving progesterone and in both FEV(1) and TL(CO) after starting progesterone in six patients who had data before and after starting treatment. This study documents the rapid decline in lung function in lymphangioleiomyomatosis, confirms the wide variation between patients, and provides some support for the suggestion that disease progression may be reduced by progesterone. The data provide a basis for designing prospective studies of treatment for lymphangioleiomyomatosis.

Relationship between ozone and respiratory health in college students: A 10-year study

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Long-term residence in areas of high ozone: associations with respiratory health in a nationwide sample of nonsmoking young adults [dsee comments]

Few studies have examined the respiratory effects of multiyear ozone exposures in human populations. We examined associations between current respiratory health status and long-term ozone exposure histories in 520 Yale College (New Haven, CT) students who never smoked. Questionnaires addressed current respiratory symptoms, respiratory disease history, residential history, and other factors. The symptoms of cough, phlegm, wheeze apart from colds, and a composite respiratory symptom index (RSI) were selected as outcome measures. Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV(1)), forced expiratory flow rate between 25 and 75% of FVC (FEF(25-75)), and forced expiratory flow rate at 75% of FVC (FEF(75)) were obtained by forced expiration into spirometers. Ozone exposure was treated as a dichotomous variable, where subjects were assigned to the high-exposure group if they lived for 4 or more years in a U.S. county with 10-year average summer-season daily 1-hr maximum ozone levels [greater/equal to] 80 ppb. Lung function and respiratory symptoms were analyzed by multiple linear and logistic regression on ozone exposure, controlling for covariates. Lung function was lower in the group with high ozone exposures: differences were statistically significant for FEV(1) [-3.1%; 95% confidence interval (CI), -0.2 to -5.9%] and FEF(25-75) (-8.1%; CI, -2.3 to -13.9%), and nearly so for FEF(75) (-6.7%; CI, 1.4 to -14.8). Gender-specific analyses revealed stronger associations for males than for females. The symptoms of chronic phlegm, wheeze apart from colds, and RSI were increased in the ozone-exposed group, with odds ratios of 1.79 (CI, 0.83-3.82), 1.97 (CI, 1.06-3.66), and 2.00 (CI, 1.15-3.46), respectively. We conclude that living for 4 or more years in regions of the country with high levels of ozone and related copollutants is associated with diminished lung function and more frequent reports of respiratory symptoms.

The adverse effect of low levels of ambient air pollutants on lung function growth in preadolescent children

The main purpose of our study was to assess the effect of low concentrations of ambient air pollution on lung function growth in preadolescent children. We accounted for height velocity over the follow-up period and also for other possible confounders such as baseline anthropometric and physiologic characteristics of children. In addition to outdoor air pollution, we considered the possible effects of social class and exposure to indoor pollutants such as gas stove fumes or environmental tobacco smoke. The cohort prospective study was carried out in 1,001 preadolescent children from two areas of Krakow, Poland, that differed in ambient air pollutants. In the city center (higher pollution area), the mean annual level [+/- standard deviation (SD)] of suspended particulate matter was 52.6 +/- 53.98 microg/m(3) and that of SO(2) was 43.87 +/- 32.69 microg/m(3); the corresponding values in the control area were 33.23 +/- 35.99 microg/m(3) and 31.77 +/- 21.93 microg/m(3). Mean lung function growth rate adjusted to height velocity and lung function level at the study entry was significantly lower in boys and girls living in the more polluted areas. Also, the proportion of children with the slower lung function growth (SLFG) was higher in the children from the more polluted area of the city. The analysis completed in the group of children after the exclusion of asthmatic subjects and those with asthmalike symptoms confirmed that, in boys, odds ratios (ORs) for SLFG [forced vital capacity (FVC)] and air pollution after adjustment to baseline FVC, height, and growth rate was significant [OR = 2.15; 95% confidence interval (CI), 1.25-3. 69)]. The analysis also confirmed that for SLFG(FEV(1)) the OR was 1. 90 (CI, 1.12-3.25). The corresponding OR values in girls were insignificant (OR = 1.50; CI, 0.84-2.68 and OR = 1.39; CI, 0.78-2. 44). The association between ambient pollutants and poorer gain of pulmonary volumes in children living in more polluted areas suggests that air pollution in the residence area may be a part of the causal chain of reactions leading to retardation in pulmonary function growth during the preadolescent years.

A study of pulmonary profile of hypertensive patients--comparison of atenolol vs amlodipine

Two groups of drugs commonly used for the treatment of hypertension are atenolol and amlodipine. These drugs are reported to have conflicting changes on pulmonary responses. In order to study the effect of hypertension and antihypertensive treatment on pulmonary responses, 40 patients with essential hypertension having diastolic blood pressure between 90-114 mmHg on three consecutive weekly visits were taken. Pulmonary responses were tested at the end of 2 weeks of placebo washout period and then at the end of 6 weeks of treatment with either atenolol or amodipine. Using a computerized autospiror along with the weekly recordings of heart rate and blood pressure, the various pulmonary and cardiac parameters were taken. Analysis of the result showed that atenolol treatment resulted in significant decline of forced vital capacity (FVC), % forced vital capacity (%FVC), and forced expiratory volume in first second (FEV1) whereas amlodipine did not show any significant change on pulmonary parameters.

Double intratracheal instillation of keratinocyte growth factor prevents bleomycin-induced lung fibrosis in rats

Alveolar re-epithelialization is necessary in the repair of damaged alveolar epithelium after lung injury. Keratinocyte growth factor (KGF) has been shown to be a potent proliferation and differentiation factor for rat alveolar type II cells. The present study examined whether KGF would prevent bleomycin-induced lung fibrosis. Adult rats were anaesthetized and recombinant human KGF (rhKGF) (150 micrograms/kg) or saline was injected intratracheally at 48 h before and 24 h after bleomycin (Bleo, 5 mg/kg) instillation. Seven and 14 days after the last administration, rat lungs were processed for lung physiology, immunohistochemistry, and in situ hybridization. Double instillation of KGF prevented the loss of body weight and reduction in total lung capacity (TLC) due to Bleo, and markedly attenuated the protein accumulation and mRNA expression of collagen types I and III and the decreased expression of surfactant protein mRNAs in the fibrotic lesions of Bleo-treated rats. KGF may play an important role in maintaining alveolar epithelium and repairing the damaged epithelium after lung injury.

Diagnostic role of residual volume in paediatric patients with chronic symptoms of the lower airways

In bronchial asthma, measurement of absolute lung volumes may reveal lung dysfunction more readily than forced expiratory spirometry. Sixty-one children (aged 4-16 years) with mild to moderate bronchial asthma and 35 children (aged 7-16 years) with other symptoms of the lower airways (OSLA) were studied, and the plethysmographic results were compared with data obtained from 36 healthy volunteers aged 6-16 years. In the first test session, repeatability of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), residual volume (RV), functional residual capacity (FRC) and total lung capacity (TLC) were good. Control subjects were also tested the next day, and intra-subject variability of repeat pulmonary function testing was in the normal range. The FEV1/FVC ratio was significantly higher in control subjects than in patients with asthma or OSLA, but only the decrease in RV after bronchodilator challenge separated patients with asthma from patients with OSLA. Changes in FEV1 and RV after bronchodilator challenge had a significant, although low, inverse correlation. An increase of > or = 5% in FEV1 had a positive predictive value of 44% and a negative predictive value of 68% for the clinical diagnosis of bronchial asthma; for a decrease of > or = 24% in RV, the figures were 86% and 71% respectively. The support of baseline absolute lung volumes on clinical decision-making is not necessarily great. Bronchodilator response, particularly in RV, is more pertinent and may enhance the detection of reversible lung dysfunction.

The effect of deep inspiration on methacholine dose-response curves in normal subjects

Normal subjects develop exaggerated airway narrowing when deep inspiration (DI) is voluntarily suppressed during methacholine challenge. Failure of periodic inflation may interfere with the bronchodilating effect of DI, and this may be fundamental to the difference in bronchodilation caused by DI in asthmatics and normal subjects. To determine whether repeated exhalations to residual volume (RV) and/or incomplete inspiration to baseline total lung capacity (TLC) could contribute to exaggerated narrowing during challenge, we tested 10 subjects on three separate days using modified methacholine challenge protocols. On Day 1, partial and complete flow volume curves were obtained after each dose. On Day 2, DI was prohibited, but partial curves were performed. On Day 3, DI and exhalation to RV were prohibited. TLC was measured pre- and post-challenge on each day. After comparable doses of methacholine, there was a greater change in FEV1 on Day 2 (27+/-15) and Day 3 (38+/-17) than on Day 1 (14+/-8) (p < 0.05). There were no differences in changes in FEV1 and FVC between Days 2 and 3, or in TLC between all 3 d. We conclude that exaggerated airway narrowing occurs in normal subjects when DI is prohibited and that this effect is not due to repeated expiration to RV, nor due to an artifact caused by a failure to inhale to TLC.

Inhaled budesonide reduces lung hyperinflation in children with asthma

Previous studies have shown that asthmatics have hyperinflation as defined by larger total lung capacity. The present study was set up in order to document changes in asthma clinic, airway calibre, airway reactivity and lung volumes after budesonide treatment. After a 2-week run-in period, 28 children with moderate persistent asthma were treated in a double-blind manner either with budesonide (0.4 mg/day) or placebo for 8 weeks and, thereafter, all patients were treated with open-label budesonide for a further 20 weeks. Symptoms, bronchodilator requirements and airway calibre improved significantly after 8 weeks of treatment (p < 0.05 for each) and prolonged treatment did not cause any further improvement. Reduction in hyperreactivity was apparent only after 20-28 weeks of treatment. Total lung capacity decreased along with budesonide treatment in both groups suggesting that early introduction of an inhaled corticosteroid may be useful in the prevention of asthma-related remodelling of the lung and thoracic cage.

Prostacyclin analog OP2507 prevents pulmonary arterial and airway constriction during lung preservation and reperfusion

BACKGROUND

The effects of OP2507 on lung preservation with cold Euro-Collins solution and during the reperfusion period were evaluated.

METHODS

For this study, canine lungs were flushed with a 10 micrograms/ml OP2507 solution (n = 7) or saline solution (control group, n = 7) (0.1 ml/kg body weight) and stored in the same solution. Pulmonary arterial pressure, pulmonary vascular resistance, airway pressure, respiratory capacity, and wet to dry weight ratio of the lungs were measured before and after 24 hours of cold preservation and after a 60-minute reperfusion period.

RESULTS

Treatment with OP2507 significantly attenuated increases in pulmonary arterial pressure, pulmonary vascular resistance, and airway pressure after preservation and during the reperfusion period. Oxygen tension in outflow blood also was maintained with OP2507 treatment throughout the experimental period, whereas it was depressed during the reperfusion period in the control group. By electron microscopy, there was little evidence of vascular endothelial damage, such as cell swelling, detachment of endothelial cells from the lamina, and attenuation of the cytoplasm, in both groups. However, the tight junctions between cells were observed more clearly in the control group than in the OP2507 group, suggesting more cell membrane damage in the control group.

CONCLUSIONS

Pretreatment with OP2507 prevented pulmonary artery and airway constriction after 12 hours of cold lung preservation and a decrease of oxygen tension in outflow blood during a 60-minute reperfusion period.

Inhaled bronchodilators reduce dynamic hyperinflation during exercise in patients with chronic obstructive pulmonary disease

Dynamic hyperinflation (DH) is a major pathophysiologic consequence of airflow limitation during exercise in patients with chronic obstructive pulmonary disease (COPD) and an important contributing factor to breathlessness. In this study we aimed to examine the effect of inhaled beta agonist therapy on DH during exercise in these patients and the relationship between changes in DH and breathlessness. In 13 COPD patients (mean age 65.1 +/- 2.0, FEV1 1.20 +/- 0.17, FEV1/FVC 40 +/- 3) we measured pulmonary function tests, exercise breathlessness by Borg score, and exercise flow volume and pressure volume loops on two separate days. Prior to testing, patients randomly received inhaled placebo or albuterol on the first test day and the alternative medication on the second test day. From measurements of exercise inspiratory capacity (IC), we calculated the end-expiratory and end-inspiratory lung volumes (EELV, EILV). We used esophageal pressure recordings to measure peak inspiratory esophageal pressure (Pesins) during exercise and this was related to the maximal capacity for pressure generation taking into account lung volume and airflow changes (Pcapi). Bronchodilator caused significant increase in both FEV1 and FVC (+0.23 and +0.51, p<0.01). Comparisons of breathlessness, exercise volumes, and pressures were made at the highest equivalent work load. There was a significant reduction in the peak exercise EELV/TLC (80 +/- 0.02% to 76 +/- 0.02%, p<0.05) while the peak EILV/TLC decreased by 2% (97 +/- 1% to 95 +/- 1%, p<0.05). The peak Pesins/Pcapi decreased (0.79 +/- 0.10 to 0.57 +/- 0.05, p<0.05), and the Pcapi - Pesins increased (7.4 +/- 3 to 13.0 +/- 3 cm H2O, p<0.05). There was significant improvement in neuroventilatory coupling for volume change (Pesins/Pcapi/VT/TLC 5.45 +/- 0.5 to 3.25 +/- 1.0, p<0.05). There was a significant reduction in breathlessness as measured by Borg score (4.5 +/- 0.7 to 3.1 +/- 0.5, p<0.05) and there was a significant correlation between delta Borg and delta EILV/TLC (r=0.771, p<0.01) with a trend for Pesins/Pcapi/VT/TLC (r=0.544, p=0.067). There was also a significant correlation between delta EELV/TLC and delta Pesins/Pcapi/VT/TLC (r=0.772, p<0.01). The relationships between delta Borg, delta resting volumes, and flow rates were not significant. We conclude that in patients with COPD, inhaled bronchodilator reduces exercise DH and improves inspiratory pressure reserve and neuroventilatory coupling. Changes in DH and neuroventilatory coupling were the main determinants of reduced breathlessness.

Effects of lactate on cross-spectral analysis of heart rate, blood pressure, and lung volume in normal volunteers

Baroreceptor reflex sensitivity, coherence functions, and transfer functions between respiration and heart rate, and between respiration and blood pressure, were studied in nine normal volunteers before and after intravenous sodium lactate infusions. Cross-spectral analysis was used to examine heart rate, finger blood pressure, and respiration obtained with the subjects in a supine posture during spontaneous breathing. Sodium lactate produced a significant decrease of the modulus between respiration and heart rate (beats/min/l). There was no such change for the placebo infusions. The absence of a significant difference in the modulus between systolic blood pressure and heart rate for placebo or lactate indicated that there were no significant changes in the baroreceptor sensitivity index. These findings suggest that lactate infusions are associated with a decrease in cardiac vagal function.

Effects of inspired gas composition during anaesthesia for abdominal hysterectomy on postoperative lung volumes

We have studied 51 patients who were allocated randomly and prospectively to receive either 100% oxygen (n = 16), 70% nitrous oxide in oxygen (n = 18) or 30% oxygen in nitrogen (n = 17) as the inspired gas during anaesthesia for abdominal hysterectomy. Lung volumes were measured before and after surgery. TLC, VC, FVC and FEV1 but not RV or FRC were reduced after surgery. There were no significant differences between the three treatment groups in any of the lung volumes measured. We conclude that absorption atelectasis during anaesthesia is not the main cause of perioperative changes in lung volume after abdominal hysterectomy. Any effect of the inspired gas is likely to be of limited clinical significance.