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Biomedical subjects

R T Abboud

Publications and source records attributed to R T Abboud.

At least 37 records · Page 2Linked to original sources
PubMed1992

Discordance of airflow limitation and ventilatory inhomogeneity in asthma and cystic fibrosis.

Although it is known that both airflow rates and gas distribution are impaired in asthma and cystic fibrosis (CF), the concordance of the change in these defects between two points in time has not been studied. On two separate occasions, the FEV1, FVC and slope of Phase III (SBN2/L%) of the single breath nitrogen test were determined, as well as the concordance between the change in these indices in 14 healthy subjects, 14 subjects with asthma, and seven subjects with CF. The coefficient of variation within a test session averaged less than 5% for the FEV1 and less than 10% for the SBN2/L% within each group. The change in FEV1 correlated with the change in FVC in all three groups, but did not correlate with the change in SBN2/L% in any group. In seven of the 14 cases of asthma and six of the seven cases of CF (outliers), the differences in the indices (expressed as the change in percent predicted) were greater than the differences observed in the control group. In three of the asthmatic and four of the CF outliers, the changes were as predicted, that is, both tests returned toward normal, or both became more abnormal. In two of the asthmatic and CF outliers both the FEV1 and SBN2/L% increased, while both decreased in the other two asthmatic outliers. Although some of the same factors will affect both indices, a worsening of ventilation inhomogeneity, which will affect the SBN2/L%, could occur with an improvement in ventilatory flow rate. Alternatively, airflow limitation could worsen but be accompanied by an improvement in ventilation homogeneity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

A sensitive double-sandwich ELISA for neutrophil elastase. Assay results in unconcentrated bronchoalveolar lavage fluid.

We developed a sensitive double-sandwich ELISA assay for neutrophil elastase (NE) using affinity-purified NE antibody. The assay was capable of detecting NE levels of 0.2 ng/ml and was used to determine NE in bronchoalveolar lavages (BAL) of 12 healthy subjects (6 nonsmokers and 6 smokers) with a mean age of about 27 yr. NE levels in the unconcentrated cell-free supernatant of BAL, subjected to high-speed centrifugation (17,000 x g for 30 min) to sediment subcellular debris, were similar in the smokers who abstained overnight from smoking and in the nonsmokers (24.4 +/- 13.9 versus 23.7 +/- 12.3 ng/mg [SD] albumin). NE levels were significantly higher in lavage fluid not subjected to high-speed centrifugation, reflecting the presence of NE bound to subcellular debris that was sedimented by high-speed centrifugation. Concentration by ultrafiltration through a Millipore CX-10 filter was accompanied by loss of protein with a relatively greater loss of NE than albumin, resulting in lower NE/albumin ratios in concentrated than in unconcentrated lavage. It is therefore recommended that NE levels be determined on unconcentrated BAL after high-speed centrifugation to sediment subcellular debris.

Adult↗
PubMed1991

Relationship between severity of rheumatoid arthritis and serum alpha 1-antitrypsin.

We determined serum alpha 1-antitrypsin phenotypes and levels in 281 patients with classical or definite rheumatoid arthritis (RA). The prevalence of the MZ phenotype in our patients with RA was not increased, as there were only 3 MZ cases (1.1% of all cases and 1.4% of seropositive cases) compared to the 3% prevalence in controls. The FM phenotype was detected in 6 cases, a prevalence rate of 2.1%, significantly higher than in controls (prevalence less than 0.4%). Increased serum levels of alpha 1-antitrypsin were independently associated (p less than 0.01) with the presence of wrist joint erosions and the use of gold and/or penicillamine for treatment; this association may represent a serum antitrypsin response to more severe disease.

Adult↗
PubMed1990

A comparison of enprofylline and theophylline in the maintenance therapy of chronic reversible obstructive airway disease.

To compare the efficacy and side effects of two xanthine derivatives in the maintenance therapy of reversible obstructive airway disease, 242 patients were assigned in randomized, double-blind fashion to receive either oral enprofylline or theophylline for 5 weeks in addition to their usual maintenance regimens. After a week of placebo xanthine therapy, enprofylline-treated patients received 150 mg of this drug twice daily (b.i.d.) for 3 days, 300 mg b.i.d. for 2 weeks, and 450 mg b.i.d. for 2 weeks. Theophylline was administered in identical doses, except that the final dosage increase was not made if plasma theophylline was 12 mg/ml or higher. At 300 mg b.i.d., both drugs significantly increased morning peak expiratory flow rate (PEFR), the mean increase above baseline being significantly higher for theophylline-treated patients (29.9 +/- 37.2 L/min) than for enprofylline-treated patients (17.4 +/- 36.9 L/min) (p = 0.023). At 450 mg b.i.d., improvement in morning PEFR was not significantly different between theophylline-treated (31.5 +/- 44.4 L/min) and enprofylline-treated groups (23.5 +/- 48.4 L/min). Evening PEFR, FEV1, and asthma symptom scores also improved significantly, demonstrating no significant difference between groups. The incidence of side effects was also similar between groups. We conclude that both enprofylline and theophylline offer useful bronchodilatation in the maintenance therapy of asthma, enprofylline, 450 mg b.i.d., being approximately equivalent to theophylline, 300 or 450 mg b.i.d.

Adolescent↗
PubMed1990

Pulmonary capillary blood volume in emphysema.

We determined single breath diffusing capacity (DLCO) and pulmonary capillary blood volume (Vc) in a total of 110 patients, who were being evaluated for resectional lung surgery for a localized tumor or lesion. Pathologic assessment of emphysema was obtained in 55 cases who had resection of a lung or an upper lobe, based on a standard reference panel for emphysema grading. In 86 cases, the extent of emphysema was quantitated by computed tomography (CT) of the chest. There was a significant negative correlation between Vc and emphysema assessed by either pathology or CT (r = about -0.5, p less than 0.001) similar to the correlation between DLCO and the extent of emphysema. Results of Vc were significantly lower in cases with moderate emphysema (pathologic grade greater than or equal to 30) than those with no emphysema (grade less than or equal to 5) (p less than 0.001) or mild emphysema (grade 10 to 25) (p less than 0.05), and they were significantly lower (p less than 0.05) in the group with mild emphysema compared with the group with no emphysema on pathologic assessment similar to DLCO results. Although Vc was reduced in emphysema, determination of Vc did not result in improved discrimination in separating cases with emphysema from those without emphysema when compared with DLCO.

Adult↗
PubMed1990

Emphysema in silicosis. A comparison of smokers with nonsmokers using pulmonary function testing and computed tomography.

The presence of emphysema in silicosis is believed to be secondary to the development of progressive massive fibrosis (PMF). However, it is difficult to separate out other causative factors, particularly cigarette smoking. In order to attempt to distinguish these factors, we examined 30 patients with silicosis by means of pulmonary function testing and computed tomography (CT) scans of the chest. Eighteen of these patients were either exsmokers or current smokers, and 12 of them were nonsmokers. The CT scans were read independently by two observers on two separate occasions. Silicosis was graded on a 5-point scale from 0 to 4; emphysema was graded as a percentage of lung involved. Percent emphysema was associated with level of pulmonary function (FEV1, FVC, and DLCO) independent of its association with either cigarette smoking or silicosis grade (p less than 0.01). Silicosis grade was associated with DLCO (p less than 0.05) independent of its association with either cigarette smoking or percent emphysema, but was not associated with level of FEV1 or FVC. In the group without PMF (silicosis Grade 0, 1, or 2), smokers had worse emphysema than nonsmokers (p less than 0.01); there was no such difference among the patients with PMF (silicosis Grade 3 or 4). Only one of the nonsmoking subjects with silicosis but without PMF had any emphysema detected on CT. Our data suggest that silicosis, in the absence of PMF, does not cause significant emphysema, and that it is primarily the degree of emphysema rather than the degree of silicosis that determines the level of pulmonary function.

Adult↗
PubMed1990

Quantitation of emphysema by computed tomography using a "density mask" program and correlation with pulmonary function tests.

We used a CT program "density mask" outlining areas with attenuation values less than -910 HU, to indicate areas of emphysema on a chest CT and to provide an overall percentage of lung involvement by emphysema. The "density mask" quantitation of emphysema was previously shown to correlate well with the pathologic assessment of emphysema in patients undergoing lung resection. We compared the CT quantitation of emphysema with mean lung density, overall lung volume on CT and pulmonary function tests in 85 patients. There was a significant correlation between the extent of emphysema on CT and FEV/FVC percent of predicted, functional residual capacity percent predicted and Dsb percent predicted. Determination of the percentage of lung with areas of low attenuation by CT provides a useful method for quantitating emphysema in life and correlates significantly with pulmonary function tests.

Adult↗
PubMed1989

Comparison of single breath carbon monoxide diffusing capacity and pressure-volume curves in detecting emphysema.

To evaluate the sensitivity of diffusing capacity (DLCO) and pressure-volume (P-V) curves in the detection of emphysema, these tests were compared with pathologic assessment of emphysema in patients undergoing lung resection for a localized tumor, and with the overall extent of emphysema as assessed by computed tomography (CT). The resected lung specimens were fixed in the inflated state and cut at 1-cm intervals in the horizontal plane. The pathologic extent of emphysema was quantitated by comparison with a standard reference panel of emphysema grading. The overall extent of emphysema on CT was assessed by a visual scoring system in a total of 55 patients, 19 undergoing lung resection and 36 not undergoing lung resection. Analysis of 37 patients by pathology scores revealed 18 with no or trivial emphysema (emphysema grades less than or equal to 5; mean grade, 2.2 +/- SD 2.6) and 19 with emphysema (grades greater than or equal to 10; mean grade, 33.2 +/- SD 24.2). Diffusing capacity, the ratio of DLCO to alveolar volume (DLCO/VA), maximal lung elastic recoil (PLmax), and lung elastic recoil at 90% of total lung capacity (PL90) were significantly different between the two groups, whereas K (the exponential constant describing the shape of the P-V curve) was not. The pathology grade of emphysema showed a significant correlation with (DLCO) (r = -0.53) and DLCO/VA (r = -0.55), which was greater than the correlation with PLmax (r = -0.42) and PL90 (r = -0.43).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Goodpasture's syndrome: recurrence after a five-year remission. Case report and review of the literature.

Herein is reported the case of a man who has had a recurrence of Goodpasture's syndrome following a five-year remission. The patient presented initially in 1977 at the age of 28 with Goodpasture's syndrome manifested by pulmonary hemorrhage without clinical evidence of renal disease, and positive antiglomerular basement membrane antibody. Following treatment with corticosteroids, remission occurred and the serum antiglomerular basement membrane antibody became negative. In 1983, he experienced a relapse with the reappearance of serum antiglomerular basement membrane antibody, the development of severe life-threatening intrapulmonary hemorrhage, and hematuria. This case illustrates that life-threatening relapse may occur in Goodpasture's syndrome despite a prolonged remission and the disappearance of detectable antiglomerular basement membrane antibody in the circulation.

Adrenal Cortex Hormones↗
PubMed1988

Bronchial leukocyte proteinase inhibitor levels in bronchial washings in asthma patients.

To evaluate whether epithelial damage of airways in asthma could be related to diminished levels of the low molecular weight bronchial leukocyte proteinase inhibitor (BLPI) in airways, we determined BLPI in bronchial washings of 13 asthma patients and 13 healthy subjects, using a sensitive enzyme-linked immunoassay. The patients had asthma due to western red cedar and had bronchial washings done 24 to 48 hours after a mild to moderate asthmatic reaction induced by inhalation challenge. We did not find significant differences in BLPI concentrations in lavage fluid of asthma patients and healthy control subjects. The ratios of BLPI to albumin levels in bronchial washings appeared to be lower among asthmatic patients, but this difference was mainly due to an increase in albumin levels in lavage fluid in asthma. In addition, there were no significant differences in BLPI levels in washings obtained from main and segmental bronchi in both control subjects and asthma patients.

Adult↗
PubMed1988

"Density mask". An objective method to quantitate emphysema using computed tomography.

We used a computed tomography (CT) scanner program ("density mask") that highlights voxels within a given density range to quantitate emphysema by defining areas of abnormally low attenuation. We compared different density masks, mean lung attenuation, visual assessment of emphysema and the pathologic grade of emphysema in 28 patients undergoing lung resection for tumor. In each patient, a single representative CT image was compared with corresponding pathologic specimens of tissue. There was good correlation between the extent of emphysema as assessed by the density mask and the pathologic grade of emphysema. The optimal attenuation level to define areas of emphysema may vary in different scanners, but, once determined for a particular scanner, the density mask accurately assesses the extent of emphysema and eliminates interobserver and intraobserver variability. It has the added advantage of determining the exact percentage of lung parenchyma showing changes consistent with emphysema.

Adult↗
PubMed1987

Noncardiogenic pulmonary edema caused by decompression sickness: rapid resolution following hyperbaric therapy.

Noncardiogenic pulmonary edema is a recognized but uncommon manifestation of type 2 decompression sickness. It typically occurs within 6 hours of a dive. Because the adult respiratory distress syndrome in this setting is believed to be due to microbubbles in the pulmonary vasculature, recompression in a hyperbaric chamber has been recommended as a form of therapy. A patient developed noncardiogenic pulmonary edema following a seawater dive to 75 feet. There was complete radiologic and clinical resolution within 5 hours of hyperbaric therapy.

Adult↗
PubMed1987

Effect of smoking on functional activity of plasma alpha 1-protease inhibitor.

We determined the levels of alpha 1-protease inhibitor, the plasma trypsin-inhibiting capacity (TIC), and elastase-inhibiting capacity (EIC) in 29 nonsmokers and 30 smokers, who were healthy volunteers matched for age (mean age, 39 +/- 12 years [+/- SD]). The functional activity of plasma alpha 1-protease inhibitor (in micrograms of enzyme inhibited per microgram of alpha 1-protease inhibitor) was slightly but significantly lower in smokers, compared with nonsmokers, both for TIC and EIC (smokers' TIC and EIC were 88.0 +/- 16.2 percent (+/- SD) and 90.4 +/- 17.9 percent of the respective mean values in nonsmokers; p less than 0.05). Among smokers, there was a significant negative correlation (r = -0.37; p less than 0.05) between the average number of cigarettes smoked per day and the functional activity of plasma alpha 1-protease inhibitor; the seven subjects who smoked 40 or more cigarettes per day had significantly lower EIC and TIC than the remaining smokers. In 12 smokers tested before and after a two-hour period of intense smoking of eight cigarettes, there was a statistically significant decrease (p less than 0.05) in EIC one hour after smoking to 93.9 +/- 2.5 percent (+/- SE) of the initial value prior to smoking. It is concluded that there is a slight but significant decrease in the functional activity of plasma alpha 1-protease inhibitor in smokers, both for TIC and EIC.

Adult↗
PubMed1986

Acute effect of smoking on elastaselike esterase activity and immunologic neutrophil elastase levels in bronchoalveolar lavage fluid.

In order to determine the acute effect of smoking on elastase in bronchoalveolar lavage fluid (BAL), we obtained BAL from 30 smokers twice, the first before smoking (after 8 h of abstinence) and the second 2 min to 1 h after the subjects had smoked either 2 or 4 cigarettes. Bronchoalveolar lavage was concentrated 100-fold and was assayed for elastaselike activity against succinyl-trialanyl-p-nitroanilide (SLAPN) as substrate. Elastolytic activity against insoluble 3H-elastin and immunologic neutrophil elastase levels tested with a sensitive enzyme-linked immunosorbent assay were determined in some subjects. No activity against insoluble 3H-elastin was detected using a sensitive assay capable of detecting subnanogram quantities of elastase. Total elastaselike activity in BAL against SLAPN was significantly (p less than 0.02) increased in smokers prior to smoking (47.4 +/- SD 20.2 ng human neutrophil elastase (HNE) equivalents) when compared with BAL from 7 nonsmokers (26.3 +/- SD 13.4 ng HNE); however, there was no significant change in enzyme activity in smokers' BAL after smoking. Assays with EDTA and phenyl-methyl-sulfonyl-fluoride as inhibitors suggested that approximately two thirds of elastaselike activity was due to a metalloprotease and that there was negligible serine protease activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Methylene blue decreases the functional activity of alpha-1-protease inhibitor in bronchoalveolar lavage.

Methylene blue, used as an external marker for bronchoalveolar lavage (BAL) in a concentration of 1 microgram/ml, reduced the functional activity of BAL alpha 1-protease inhibitor (alpha 1-PI) in 2 healing nonsmokers who each had 2 BAL done, one with and the other without methylene blue. Inactivation of alpha 1-PI by methylene blue was confirmed by in vitro experiments on diluted serum and concentrated BAL incubated with methylene blue. Inactivation of alpha 1-PI is likely due to its oxidation by methylene blue, as suggested by the in vitro protective effect of dithiothreitol, a reducing agent. These observations indicate a need for caution when considering the use of methylene blue as an external marker for bronchoalveolar lavage.

Blood Proteins↗
PubMed1986

Effect of smoking on plasma neutrophil elastase levels.

Plasma elastase is considered to indicate neutrophil elastase that has been released in vivo and has complexed with plasma inhibitors. Because smoking may play a pathogenetic role in emphysema by inducing elastase release in the lung, which may be reflected in the plasma elastase level, we evaluated the effect of smoking on plasma elastase in healthy men by using an enzyme-linked immunosorbent assay. No significant difference was found in plasma elastase levels between 30 smokers and 29 nonsmokers (103 +/- 23 [SD] ng/ml vs. 97 +/- 23 ng/ml). We found no significant change in plasma elastase level in eight heavy smokers when we compared morning with afternoon plasma samples taken about 7 hours later, while the subjects continued to smoke ad libitum in the interval. However, we found a significant rise in plasma elastase level in 12 healthy smokers who were tested after 8 hours of abstinence from smoking and then immediately and 1/2, 1, and 2 hours after intense smoking (eight cigarettes smoked over a period of 2 hours). Neutrophil count increased from a baseline of 3.8 +/- 0.7 X 10(3)/mm3 to 8.0 +/- 2.5 X 10(3)/mm3 at 1 hour, and 8.8 +/- 3.1 X 10(3)/mm3 at 2 hours. Plasma elastase level increased significantly (P less than 0.02) from a baseline of 111 +/- 30 ng/ml to 141 +/- 24 ng/ml at 1 hour after completion of smoking, but was not significantly different from baseline 2 hours after smoking (130 +/- 34 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Carboxyhemoglobin↗
PubMed1985

Acute effect of smoking on the functional activity of alpha1-protease inhibitor in bronchoalveolar lavage fluid.

To assess the acute effect of smoking on the functional activity of alpha1-protease inhibitor (alpha-Pl) in bronchoalveolar lavage (BAL), we studied 38 smokers (mean age 25 +/- 6.5 yr), who had 2 fiberoptic bronchoscopic lavages in sequence, the first after 8 h of abstinence from smoking, and the second at varying time intervals after smoking. Twenty-two smokers were tested before, and 10 min to 3 h after, smoking 2 medium-tar filter cigarettes; 16 smokers were were tested before, and 2 min to 60 min after, smoking 4 cigarettes. Eight nonsmoking volunteers had 2 BAL performed in sequence as control subjects. Initial BAL from control subjects and from smokers after 8 h of abstinence had similar alpha-Pl activity (mean 0.495 +/- SD 0.017 micrograms of pancreatic elastase/micrograms alpha-Pl, about 90% of the activity of purified alpha-Pl). After smoking, we did not find significant inactivation of alpha-Pl except in the 6 smokers lavaged 1 h after smoking 2 cigarettes, whose alpha-Pl activity decreased slightly to 90.0 +/- SD 10.6% of their initial activity (p less than 0.05). We also obtained BAL from 7 smokers only after smoking, and did not find inactivation of alpha-Pl. We conclude that in young healthy smokers: (1) alpha-Pl in BAL after 8 h of abstinence from smoking is active similar to nonsmoking control subjects, and (2) after smoking 2 to 4 cigarettes, there is no, or very limited, inactivation of alpha-Pl.

Adult↗