Biomedical subjects

Z Shakoor

Publications and source records attributed to Z Shakoor.

7 recordsLinked to original sources

PubMed2001

Increased prevalence of asthma in Saudi Arabia.

BACKGROUND: Bronchial asthma is among the most common chronic illnesses of childhood. A number of reports in the recent past suggest that the prevalence of asthma is increasing globally. OBJECTIVE: To investigate the changing prevalence of asthma in the Kingdom of Saudi Arabia. SUBJECTS AND METHODS: Two populations of schoolchildren between the ages of 8 and 16 years were studied using an internationally designed protocol in 1986 and 1995. The questionnaire used in these studies was very similar to the one used in the International Study of Allergy and Asthma in Childhood. A total of 2,123 school-children in 1986 (Jeddah and Riyadh) and 1,008 schoolchildren in 1995 (Hail and Gizan) were enrolled in the surveys. These cross-sectional studies of randomly selected schoolchildren were statistically analyzed using ANOVA and a Z test. RESULTS: The comparison of data between Riyadh versus Hail (inland desert dry environment) and Jeddah versus Gizan (coastal humid environment) revealed that the prevalence of asthma in the similar populations increased significantly from 8% in 1986 to 23% in 1995 (P < .0001). Likewise, the prevalence of allergic rhinitis also increased from 20% to 25% (P < .003) since 1986. However, no significant change in the prevalence of eczema (from 12% to 13%) was noted between 1986 and 1995. CONCLUSIONS: The study indicates that there was a significant increase in the prevalence of bronchial asthma and, to a lesser extent, in the prevalence of allergic rhinitis in the Kingdom of Saudi Arabia during this 9-year period. The study also revealed increased exposure to environmental factors such as tobacco smoke and indoor animals in Saudi houses. It seems that the continuing changes in contemporary life may well have contributed to the increased prevalence of asthma in the country.

Adolescent↗

PubMed1994

Circulating adhesion molecules in sarcoidosis.

Sarcoidosis is a disease of unknown etiology characterized by non-caseating granulomata together with a number of systemic abnormalities. We have recently shown these include increased expression of the integrins CD11/CD18 on peripheral blood leucocytes. Here we have measured serum levels of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) in 23 patients and 14 normal controls using antigen capture sandwich ELISAs. Median circulating E-selectin levels in the patients were nearly three times those of the controls (P < 0.0001, Mann-Whitney U-test), whilst ICAM-1 but not VCAM-1 levels were only slightly elevated. These results show that endothelial cell activation and shedding of E-selectin into the circulation are additional features of the pathology of sarcoidosis.

Adult↗

PubMed1992

A new method for measuring clustering in suspension between accessory cells and T lymphocytes.

Specifying the molecular basis and clinical significance of cluster formation between antigen-presenting cells and T lymphocytes will be important in many areas of immunology. In this paper we describe a novel and reproducible technique for measuring cluster formation in suspension between purified human blood monocytes and purified autologous T lymphocytes, and its application to determining the effects of recall antigens and mitogen. Blood monocytes and T lymphocytes from eight normal subjects were separately prelabelled with two different carbocyanine dyes prior to co-culture in suspension with or without antigen (PPD, SKSD) or mitogen (PHA). At 24 h the co-cultures were examined for cluster formation by ultraviolet microscopy and flow cytometry. Control experiments showed that the carbocyanine dyes were non-toxic in vitro, that cell labelling was stable for culture periods up to 120 h, and that the two dyes did not leak from cell to cell. By this technique we measured the proportion of monocytes clustering one or more T lymphocytes in the presence and absence of recall antigen or PHA. There was a close correlation between visual and flow cytometric measurement of monocyte: T lymphocyte clustering (p < 0.001) as well as a close relationship between the ability of the two recall antigens to increase the extent of clustering above baseline (p < 0.001). Antigen-increased cluster formation did not correlate with baseline clustering, unlike PHA-increased clustering, which was related to baseline levels (p = 0.02), suggesting the operation of distinct mechanisms. The method is applicable to measuring cell-cell associations in suspension during extended periods of culture, as well as for the study of agents which might modify intercellular adhesion processes.

Antigen-Presenting Cells↗

PubMed1992

A method of preparing blood leucocytes for flow cytometry which prevents upregulation of leucocyte integrins.

LeuCAM (CD11/CD18) cell-surface antigens are easily upregulated on cell manipulation ex vivo. A procedure for preparing leucocytes, in which human blood is immediately treated ex vivo with buffered formaldehyde and then the erythrocytes and platelets are removed by lysis and differential centrifugation, has been successfully applied to the analysis of LeuCAM antigen expression by flow cytometry. We show that the increased expression of monocyte CD11/CD18, which occurs when mononuclear leucocytes are separated by a standard Lymphoprep density gradient separation, can be avoided if cells are fixed immediately. Following this fixation polymorphs are unable to upregulate CD11/CD18 in response to fMLP stimulation in vitro. The technique produces lymphocyte, polymorph and monocyte populations that can be clearly defined on the basis of forward scatter and side scatter, and preserves the expression of various surface antigens; the percentages of gated lymphocytes expressing CD3, CD4, and CD8 were similar to those obtained using a commercial fixing and lysis solution. The processing does not render cells permeable to antibodies, as evidenced by our failure to stain cells with antibodies to intracellular antigens. We believed the method to be useful for measuring CD11/CD18 expression on blood leucocytes from normal or pathological specimens and to have application to the measurement of other cells surface antigens which may also be upregulated by the separation procedures.

Antigens, CD↗

PubMed1992

Increased CD11/CD18 expression on peripheral blood leucocytes of patients with sarcoidosis.

Sarcoidosis is a multisystem disease of unknown etiology characterized by non-caseating granulomata, formed mainly from macrophages surrounded by lymphocytes and plasma cells. Using a novel method for the preparation of blood leucocytes for flow cytometry, we report increased expression of LeuCAMs (CD11/CD18) on peripheral blood leucocytes of 11 Caucasian and 10 Afro-Caribbean patients with sarcoidosis compared with age-, sex- and race-matched controls. Whilst the percentages of the cells expressing CD11/CD18 were no different, the density, expressed as mean fluorescence intensity (MFI), was greater for all leucocytes in sarcoids than in normal individuals. The expression of intercellular adhesion molecule-1 (ICAM-1), a ligand for LFA-1 which is expressed on all leucocytes, was not significantly different from normal, whereas HLA-DR was expressed more intensely on sarcoid monocytes (P less than 0.01) and blood lymphocytes (P less than 0.005) than control cells. Our findings are consistent with leucocyte activation although we were unable to confirm reports of elevated tumour necrosis factor-alpha (TNF-alpha) in the patients' plasma using an ELISA. Increased expression of adhesion molecules on peripheral blood leucocytes may play a role in the cellular extravasation, aggregation, and granuloma formation seen in sarcoidosis.

Adult↗

PubMed1992

Alveolar macrophage accessory cell function in bronchial asthma.

The capacity of peripheral blood monocytes and alveolar macrophages (AM) obtained by bronchoalveolar lavage (BAL) to present recall antigens, namely, tuberculin purified protein derivative (PPD) or streptokinase-streptodornase (SKSD), to highly purified autologous T-cells has been studied in 11 asthmatic and 11 healthy, nonatopic normal subjects. In the asthmatic group, AM accessory cell function was variable, and most subjects were unable to present either recall antigen as effectively as blood monocytes, although one asthmatic subject demonstrated larger proliferative responses than blood monocytes for both antigens. AM accessory cell activity was not antigen-specific, and there was a correlation between accessory cell efficacy for the two antigens (r = 0.92; confidence interval, 0.53 to 0.98). Furthermore, a correlation existed between the percentage lymphocyte count in the BAL fluid and the ratio of macrophage to monocyte antigen-presenting capability for both PPD (r = 0.92; 95% confidence interval, 0.83 to 0.99) and SKSD (r = 0.90; 95% confidence interval, 0.45 to 0.98). In the normal subjects, AM were also unable to act effectively as accessory cells for the presentation of PPD and SKSD in the majority of subjects. No correlation existed between the percentage lymphocytes in BAL fluid and the ratio of AM to monocyte accessory cell function. These results suggest an association between AM accessory function and the presence of BAL lymphocytes in bronchial asthma.

Adult↗

PubMed1991

Normal and sarcoid alveolar macrophages differ in their ability to present antigen and to cluster with autologous lymphocytes.

Human bronchoalveolar macrophages from normal individuals function poorly as accessory cells for the presentation of common recall antigens. In sarcoidosis, alveolar macrophages (AM) are reported to be effective accessory cells for the presentation of such antigens. In this study normal and sarcoid AM were compared with blood monocytes for their ability to act as accessory cells in presenting tuberculin purified protein derivative (PPD) and streptokinase-streptodornase (SKSD) to autologous T lymphocytes, or to form spontaneous, antigen- or mitogen-induced clusters with the T cells. When compared to autologous monocytes, normal AM failed to present the two recall antigens effectively. Likewise normal AM formed very few clusters with T lymphocytes when compared to monocytes, even in the presence of antigens or the mitogen phytohaemagglutinin (PHA). In contrast, sarcoid AM presented both antigens as effectively, and were equally effective as monocytes in forming clusters with T lymphocytes, spontaneously and in further response to antigen or mitogen. The results suggest that in sarcoidosis enhanced accessory cell function and enhanced cluster formation may be related features of bronchoalveolar macrophage populations.

Adolescent↗