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Biomedical subjects

B A Ali

Publications and source records attributed to B A Ali.

10 recordsLinked to original sources
PubMed1998

Post-shift changes in pulmonary function in a cement factory in eastern Saudi Arabia.

This cross-sectional study was conducted in 1992 in the oldest of three Portland cement producing factories in Eastern Saudi Arabia. The respirable dust level was in excess of the recommended ACGIH level in all sections. Spirometry was done for 149 cement workers and 348 controls, using a Vitalograph spirometer. FEV1, FVC, FEV1/FVC% and FEF25-75% were calculated and corrected to BTPS. A significantly higher post-shift reduction FEV1, FEV1/FVC% and FEF25-75% was observed in the exposed subjects. Multiple regression analysis showed a significant relationship between post-shift changes and exposure to cement dust but failed to support any relationship with smoking. These findings may indicate an increase in the bronchial muscle tone leading to some degree of bronchoconstriction as a result of an irritant effect induced by the acute exposure to cement dust.

Adult↗
PubMed1998

Bronchial asthma in two chemical fertilizer producing factories in eastern Saudi Arabia.

SETTING: Two urea fertilizer producing factories in Saudi Arabia. OBJECTIVE: To determine the prevalence of respiratory symptoms and diseases in employees exposed to ammonia gas. DESIGN: A cross-sectional study involving 161 exposed subjects and 355 controls. All completed a respiratory symptoms questionnaire, with additional questions on present and past occupations. Ammonia concentrations were measured in the different sections of the factories. RESULTS: The ammonia levels in factory B were well below the threshold limit value (TLV) (range 0.02-7.0 mg/m3 of air). In factory A the range was 2.0-130.4 mg/m3. The control and exposed groups were comparable with respect to their smoking habits. The exposed subjects in factory A had significantly higher relative risks (RR) for all respiratory symptoms; the same was true for haemoptysis (RR: 4.1, 95% confidence interval: 1.63-10.28). Bronchial asthma, chronic bronchitis, and a combined diagnosis were significantly higher among those exposed to high cumulative ammonia levels. However, in the logistic regression analysis ammonia concentration was significantly related to cough, phlegm, shortness of breath with wheezing and bronchial asthma. CONCLUSION: Exposure to ammonia gas in the workplace is significantly associated with increase in respiratory symptoms and bronchial asthma. Re-engineering measures to lower the levels of ammonia in factory A are strongly recommended. The affected employees should be removed from further exposure and followed up.

Adult↗
PubMed1990

The influence of the introduction of objective structured practical examinations in physiology on student performance at King Faisal University Medical School.

The Department of Physiology at the College of Medicine and Medical Sciences, King Faisal University (KFU) had serious concerns about the effectiveness of the practical classes in motivating student learning and in achieving the objectives of these practicals. A new form of evaluation, the objective structured practical examination (OSPE) was introduced in June 1987. At KFU, the introduction of OSPE has led to a marked improvement in the mean scores for the laboratory component of the final examinations in the physiology courses. Such an improvement was not consistently observed in the other components of the examinations. Performance in stations evaluating skills was in general better than in those testing analytical and interpretive abilities. Female students performed significantly better in OSPE than male students in 4/5 and 3/5 physiology I and II examinations. Such gender differences were not observed in the written examinations.

Achievement↗
PubMed1988

Standardization of different spirometers.

This study was designed to compare spirometers used for human testing and to determine whether the results obtained by different spirometers meeting the American Thoracic Society (ATS) requirements are interchangeable. Water-sealed spirometer (Harvard), dry bellow wedge spirometer (Vitalograph) and computerized pneumotachograph (Gould), all of them satisfying the ATS recommendations were compared. Forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), forced expired flow between 25 and 75% of FVC (FEF 25-75%) and 100 FEV1/FVC (FEV1%) were selected for comparative analysis. Measurements of these parameters were carried out on a total of 40 healthy volunteers of mixed nationalities. The Vitalograph values for FVC, FEV1 and FEV1% were significantly higher than those of the water-sealed spirometer (Harvard), but were closely similar to the values obtained by the Gould computerized pneumotachograph. Our results thus do not support the interchangeability of different spirometers and stress the importance of biological standardization of spirometers against each other.

Adult↗
PubMed1981

Origin of crystalloid inclusions in macrophages I: studies of peritoneal macrophages after erythrocyte ingestion.

In an attempt to investigate the origin of crystalloid inclusions present in bone-marrow macrophages of normal adult mice and in man, murine peritoneal macrophages (which normally do not contain inclusions of this nature) were studied by light and electron microscopy 24 h after 3 daily injections of various preparations of erythrocytes. The preparations included mouse erythrocytes with and without pretreatment with collagenase, human erythrocytes and human-erythrocyte ghosts. Crystalloid inclusions were only rarely seen in the peritoneal macrophages in these circumstances. The results offered little support for the idea that crystalloid inclusions are derived from the breakdown of erythrocytes.

Animals↗
PubMed1981

Origin of crystalloid inclusions in macrophages II: evidence for derivation from eosinophil granulocyte breakdown.

Peritoneal macrophages were studied by light and electron microscopy in normal adult mice 24 h after 3 daily injections of preparations of leucocytes and platelets. Crystalloid inclusions, similar to those seen in bone marrow macrophages of normal adult mice and in man, were occasionally observed in peritoneal macrophages after administration buffy-coat white cells but not after platelets. They were much more frequently seen following the ingestion of eosinophil-rich granulocytes and were almost always associated with secondary lysosomes. Energy-dispersive analysis of X-ray provided further evidence that both crystalloid inclusions and lysosomes originated from the injected granulocytes. These observations suggest that crystalloid inclusions in marrow macrophages are derived from granulocyte breakdown and that in this respect eosinophil granulocytes are of prime importance.

Animals↗
PubMedDate not supplied

Pulmonary function of workers exposed to ammonia: a study in the Eastern Province of Saudi Arabia.

To determine the effect of chronic exposure to ammonia on pulmonary function among ammonia workers, 77 workers were randomly selected from an ammonia factory in the Eastern Province of Saudi Arabia and 355 were selected as controls from the administrative staffs of four industrial groups in Eastern Province. Spirometry was carried out and FEV1, FVC, and FEV1/FVC% were calculated. The ammonia level in the working environment was determined spectrophotometrically. 30% of the air samples had ammonia concentrations that exceeded the threshold limit value. Significant reductions in FEV1 % predicted and FVC % predicted were observed in ammonia workers exposed to higher cumulative ammonia levels (above 50 mg/m3-years). FEV1% predicted and FEV1/FVC% were significantly lower in symptomatic than in asymptomatic workers in the exposed group. These findings may raise the possibility that exposure to a high cumulative ammonia level produces a combined restrictive/obstructive ventilatory defect.

Air Pollutants, Occupational↗