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Biomedical subjects

Q A Hamid

Publications and source records attributed to Q A Hamid.

At least 55 records · Page 3Linked to original sources
PubMed1997

Adoptively transferred late allergic airway responses are associated with Th2-type cytokines in the rat.

Late allergic airway responses can be transferred by CD4+ T cells in the rat. To investigate the role of T-cell cytokines in these responses, we examined the expression of mRNA for Th2 (interleukin [IL]-4 and IL-5) and Th1 (IL-2 and interferon gamma [INF-gamma])-type cytokines in Brown Norway rats that were administered either antigen-primed W3/25(CD4)+ or OX8(CD8)+ T cells. Donors were actively sensitized by subcutaneous injection of ovalbumin (OVA) in the neck and T cells were obtained from the cervical lymph nodes by immunomagnetic cell sorting for administration to unsensitized rats. Control rats received bovine serum albumin (BSA)-primed CD4+ and CD8+ T cells. Two days later, recipient rats were challenged with aerosolized OVA, and bronchoalveolar lavage (BAL) was performed 8 h after challenge. BAL cells expressing mRNA for IL-2, IL-4, IL-5, and INF-gamma were analyzed using the technique of in situ hybridization. Recipients of OVA-primed CD4+ T cells had an increase in the fraction of BAL cells expressing mRNA for IL-4 and IL-5 compared with BSA-primed CD4+ or OVA-primed CD8+ cells (P < 0.001). Recipients of CD8+ T cells had an increase in INF-gamma mRNA expression after OVA challenge compared with recipients of BSA-primed-CD8+ or OVA-primed CD4+ T cells (P < 0.001). In conclusion, T-cell-dependent allergen-induced late responses are associated with the expression of mRNA for IL-4 and IL-5, indicating Th2 cell activation. Furthermore, the increased expression of INF-gamma in allergen challenge recipients of antigen-primed CD8+ T cells suggests that CD8+ T cells may be important in modulating allergic responses.

Adoptive Transfer↗
PubMed1996

An improved method to distinguish micrococcal nuclease sensitivity of chromatin.

The resolution of the standard micrococcal nuclease assay for sensitivity of active chromatin has been enhanced by the inclusion of an additional step of digesting nuclease-digested DNA with a suitable restriction enzyme prior to Southern hybridization. The improved assay has been used to analyze the chromatin structure of the lamin A, albumin and alpha-fetoprotein genes during rat liver development.

Animals↗
PubMed1996

Activation of the lamin A gene during rat liver development.

We have studied the regulation of expression of the A-type lamins, which are constituents of the nuclear lamina. During rat liver development, high levels of lamin A and C mRNAs were observed in 15-day fetal liver but were barely detectable in the adult. The chromatin conformation of the lamin A gene was sensitive to DNase I in 15-day fetal liver but became mostly insensitive in the adult. Lamin A and C proteins could be detected in fetal liver and persisted in the adult. Our evidence suggests that the lamin A gene is actively transcribed early in liver differentiation and its activity declines considerably in adult liver.

Animals↗
PubMed1996

Grass pollen immunotherapy inhibits allergen-induced infiltration of CD4+ T lymphocytes and eosinophils in the nasal mucosa and increases the number of cells expressing messenger RNA for interferon-gamma.

BACKGROUND: Grass pollen injection immunotherapy is effective in patients with summer hay fever, although efficacy must be balanced against possible side effects. The mechanism of immunotherapy is unknown but may be related to its ability to inhibit allergen-induced late responses, which are known to be characterized by infiltration of T lymphocytes, eosinophils, and cells with messenger RNA for so-called TH2-type cytokines (IL-4 and IL-5). OBJECTIVE: This study was designed to observe the effect of grass pollen immunotherapy on late nasal responses and associated cellular infiltration and cytokine mRNA expression. METHODS: We performed local nasal provocation with grass pollen (and a control challenge) in 28 patients after a 12-month double-blind, placebo-controlled trial of immunotherapy. Nasal biopsy specimens were obtained at 24 hours and processed for immunohistology and in situ hybridization studies. RESULTS: Grass pollen immunotherapy inhibited allergen-induced immediate (0 to 60 minutes) increases in sneezing (p < 0.02) and nasal blocking (p < 0.01) and late (0 to 24 hours) nasal symptoms (p < 0.05). Immunotherapy also inhibited the associated infiltration of the nasal mucosa by CD4+ T lymphocytes and total (major basic protein-containing) and "activated" (cationic protein-secreting) eosinophils (all p = 0.03). There was a significant (p = 0.04) increase in cells expressing mRNA for interferon-gamma at 24 hours after allergen challenge, which correlated inversely with patients' seasonal symptoms (r = -0.65, p < 0.05) and medication requirements (r = -0.75, p < 0.02) during the pollen season. CONCLUSION: The results suggest that successful grass pollen immunotherapy for summer hay fever may act by inhibiting allergen-induced T lymphocyte and eosinophil recruitment and eosinophil activation in the target organ, possibly through a mechanism involving protective local increases in TH1-type cells.

Adult↗
PubMed1996

Upregulation of Th-2 cytokine receptors in atopy- and nonatopy-associated chronic sinusitis.

OBJECTIVE: This study was conducted to investigate the expression of alpha IL5 and alpha GM-CSF receptors (alpha IL5r and alpha GM-CSFr) mRNA in the paranasal sinus mucosa of atopic and nonatopic subjects with chronic sinusitis compared to controls. DESIGN: This was a prospective study of patients presenting with the diagnosis of chronic sinusitis of at least 6 months' duration. METHOD: Fourteen patients with stable chronic sinusitis (7 atopic, 7 nonatopic) and 7 controls were included, from whom sinus mucosal biopsies were obtained and examined for membrane-bound alpha IL5r and alpha GM-CSFr mRNA using in situ hybridization. RESULTS: There was a significant difference in the number of cells expressing alpha IL5r mRNA per high-power field in both atopic and nonatopic subjects compared to controls, and in the number of cells expressing alpha GM-CSFr mRNA in both atopic and nonatopic subjects compared with controls. The number of alpha IL5r mRNA-positive cells was significantly greater in the atopic versus nonatopic groups, whereas alpha GM-CSFr mRNA-positive cells were greater in number in the nonatopic versus atopic groups. CONCLUSION: Both alpha IL5r and alpha GM-CSFr are upregulated in chronic sinusitis, suggesting that increases in both Th-2 cytokines and their receptors may be important in the pathology of the disease. Furthermore, the predominant associations of alpha IL5r with atopic chronic sinusitis and alpha GM-CSFr with nonatopic chronic sinusitis suggest that the chronic inflammation in this condition may arise from differential activation of distinct cytokine pathways depending on whether or not there is associated atopy.

Biopsy↗
PubMed1996

Interleukin-13 and interleukin-4 are coexpressed in atopic asthma.

Interleukin-4 (IL-4) is an important cytokine in the allergic inflammation associated with atopic asthma. Interleukin-13 shares many of the biological effects of IL-4, and the evidence suggests that the expression of these two cytokine genes may be coregulated. We have investigated the expression of IL-13 and IL-4 mRNA in the bronchial mucosa of nine stable atopic asthmatics and 10 normal controls, characterized the major cellular source of IL-13 mRNA, and examined the colocalization of IL-13 and IL-4 mRNA. Endobronchial biopsies were obtained and examined for IL-13 and IL-4 mRNA using radiolabeled in situ hybridization. The number of positive cells per millimeter of basement membrane for both IL-13 and IL-4 mRNA was increased significantly in the bronchial mucosa of atopic asthmatics compared to normal controls (p < .001). In the atopic asthmatics, the expression of IL-13 was significantly greater than that for IL-4 (p < .01). In these subjects, 90% of the IL-13 mRNA-positive cells were CD3-positive T cells. Furthermore, although 100% of IL-4-positive cells also expressed IL-13 mRNA, only 60% of IL-13-positive cells also expressed IL-4. These results demonstrate that, in mild atopic asthma, IL-13 and IL-4 are coexpressed and that the upregulation of IL-13 expression is greater than that of IL-4. Our data support the role of IL-13 in the allergic inflammation present in atopic asthma.

Asthma↗
PubMed1995

Properties of oligonucleosomes from active genes of rat liver.

Active chromatin fraction from rat liver nuclei has been isolated under the lower ionic strength conditions, to prevent salt induced rearrangement and exchange of linker histone H1. Salt induced higher order folding in these oligonucleosomes was determined by sedimentation, viscosity, aggregation and circular dichroism studies. Sedimentation studies indicate that upon raising the ionic strength from 25 mM to 65 mM (mainly NaCl), active oligonucleosomes show intrafragmental interaction and formation of soluble oligomers. These oligomers disaggregate into unfolded monomers at 90 mM ionic strength. In contrast, oligonucleosomes from inactive genes show gradual increase in intrafragmental higher order folding without any interfragmental interaction on raising salt concentration. A much higher decrease in viscosity of active oligonucleosomes in comparison to bulk oligonucleosomes also support the above conclusion. However, on raising salt concentration above 100 mM NaCl, both the chromatin fractions are capable of forming insoluble aggregates. Decrease in the molar ellipticities of bulk oligonucleosomes at 273 and 282 nm is observed on raising ionic strength from 25 mM to 65 mM. A different pattern of this decrease is observed in case of active oligonucleosomes, indicating adaptation of a different type of salt induced secondary structure of DNA in these oligonucleosomes. Melting profile of DNA from active and bulk chromatin suggests that the base composition of both the chromatin fractions is same.

Animals↗
PubMed1994

T lymphocytes and mast cells express messenger RNA for interleukin-4 in the nasal mucosa in allergen-induced rhinitis.

We have investigated the phenotype of interleukin-4 (IL-4) mRNA+ cells in the nasal mucosa of six subjects with allergic rhinitis before and 24 hr after local allergen provocation with grass pollen extract. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies, and immunocytochemistry (APAAP) followed by in situ hybridization performed on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, major basic protein (MBP) and CD68 were used to identify T cells, mast cells, eosinophils and macrophages, respectively. Hybridization studies were performed using a digoxigenin-labelled IL-4 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3-indoly phosphate (BCIP) served as chromogens to detect hybridization IL-4 mRNA signals. Significant increases in T lymphocytes and eosinophils and in the number of IL-4 mRNA+ cells were observed after allergen challenge. Double immunocytochemistry/in situ hybridization demonstrated that the majority of IL-4 mRNA+ cells after allergen challenge were CD3+ (73.7% +/- 1.6). Lower numbers of IL-4 mRNA hybridization signals were co-localized to tryptase+ cells (26.0% +/- 1.6). In contrast, no IL-4 mRNA hybridization signals were co-localized to either eosinophils or macrophages. These results indicate that after allergen challenge T cells are the principal cellular source of IL-4 mRNA transcripts during human late nasal responses, with a lesser contribution from mast cells.

Adult↗
PubMed1993

T cells are the principal source of interleukin-5 mRNA in allergen-induced rhinitis.

We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of subjects with allergic rhinitis. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies from six patients, before and 24 h after local allergen provocation with grass pollen. Immunocytochemistry (APAAP) was followed by in situ hybridization on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, and major basic protein (MBP) were used to identify T cells, mast cells, and eosinophils, respectively. Hybridization studies were performed using a Digoxigenin-labeled IL-5 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3- indoly phosphate (BCIP) served as chromogens to detect hybridized IL-5 mRNA signals. The majority of IL-5 mRNA+ cells were CD3+ (83.2%), whereas the remainder were either tryptase+ (11.3%) or MBP+ (5.4%). In contrast, only a few IL-5 mRNA+ cells were observed in nasal biopsies before challenge, all of which were co-localized to CD3+ cells. These results indicate that CD3+ cells are the principal cellular source of IL-5 transcripts in the nasal mucosa 24 h after allergen-induced late-phase nasal responses.

Adult↗
PubMed1993

Influence of grass pollen immunotherapy on cellular infiltration and cytokine mRNA expression during allergen-induced late-phase cutaneous responses.

We have studied the influence of grass pollen immunotherapy on cellular infiltration and cytokine mRNA expression during allergen-induced late-phase cutaneous responses. In a double-blind, placebo-controlled trial of immunotherapy in 40 adult hay fever sufferers, clinical improvement was accompanied by a decrease in the size of the late-phase skin response. When the immunotherapy-treated group was compared with the placebo group, analysis of skin biopsies obtained 24 h after intradermal allergen revealed a significant reduction in the number of infiltrating CD3+ (P = 0.04) and CD4+ (P = 0.009) cells and a trend for a decrease in EG2+ eosinophils (P = 0.08). Treatment did not influence allergen-induced recruitment of CD8+ cells, neutrophils, or macrophages. Unexpected increases in expression of CD25 (P = 0.006) and HLA-DR (P = 0.007) were observed in the actively treated group. In situ hybridization using a panel of riboprobes demonstrated "TH2-type" (IL-4, IL-5) cytokine mRNA responses in both groups of patients. In contrast, significant hybridization for IL-2 (8/16 patients, P = 0.02) and for interferon-gamma (6/16 patients, P = 0.04) was observed only in the actively treated group. These findings indicate that immunotherapy is associated with suppression of allergen-induced CD4+ T lymphocyte infiltration, but among the cells that are recruited, there is upregulation of CD25 and HLA-DR. At least in this model, immunotherapy does not appear to affect expression of TH2-pattern cytokines in response to allergen exposure, but expression of mRNA for Th1-type cytokines was enhanced in half of the patients. The results support the view that immunotherapy may possibly be working through induction of T cell tolerance.

Adult↗
PubMed1992

Cytokine messenger RNA expression for IL-3, IL-4, IL-5, and granulocyte/macrophage-colony-stimulating factor in the nasal mucosa after local allergen provocation: relationship to tissue eosinophilia.

Tissue eosinophilia is characteristic of human atopic allergic inflammation, although the mechanism is largely unknown. In this study we test the hypothesis that eosinophil infiltration during allergen-provoked rhinitis in hayfever sufferers may occur as a consequence of activation of a population of cells having a characteristic cytokine profile equivalent to the murine Th lymphocyte Th2 subset. Biopsies of the nasal inferior turbinate were obtained from 10 grass pollen-sensitive patients 24 h after local nasal provocation with allergen and after a control challenge with the allergen diluent. Biopsies were divided into two and subsequently processed for in situ hybridization using 35S-labeled RNA probes for selected cytokines and for immunohistology using an eosinophil granule mAb (EG2) which recognizes secreting eosinophils. At allergen-challenged sites compared with control sites there were significant increases in mRNA+ cells for IL-3 (p less than 0.04), IL-4 (p = 0.01), IL-5 (p = 0.02) and granulocyte/macrophage-CSF (p = 0.03). In contrast, only occasional hybridization signals were observed for IL-2 and IFN-gamma at both allergen and control sites. After allergen there was an increase (p = 0.01) in EG2+ eosinophils and significant correlations were observed between EG2+ cells and mRNA expression for "Th2-type" cytokines, particularly IL-5 (r = 0.90, p less than 0.0001). These results demonstrate that recruitment of eosinophils during human allergen-induced rhinitis is associated with cells expressing mRNA for IL-3, IL-4, IL-5, and granulocyte/macrophage-CSF.

Adult↗
PubMed1991

Localization of beta 2-adrenoceptor messenger RNA in human and rat lung using in situ hybridization: correlation with receptor autoradiography.

We have used in situ hybridization to study the localization of mRNA encoding the beta 2-adrenoceptor in tissue sections of the human and rat lung and compared this with the distribution of beta 2-receptor binding sites using receptor autoradiography. To localize beta 2-receptor mRNA, a [32P]labeled antisense RNA probe (riboprobe) was generated from human or rat beta 2-receptor cDNA. A similar distribution of beta 2-receptor mRNA was identified in both species. The highest intensity of beta 2-receptor mRNA was detected in smooth muscle of small airways, airway epithelium and pulmonary blood vessels. Lower intensity of beta 2-receptor mRNA was identified in smooth muscle of large airways, and alveolar epithelium (presumably type I and type II pneumocytes). No significant hybridization signal was detected in interstitial tissue. The specificity of the hybridization signal was confirmed with a sense probe (having identical sequence to the mRNA) and preincubation with RNase A, and by Northern blot analysis which revealed a single band of mRNA of 2.2 kb. There was a correspondence between mRNA localization and the distribution of beta 2-receptors visualized by [125I]iodocyanopindolol autoradiographically in the presence of CGP 20712 (a beta 1-selective antagonist). However, alveolar walls that showed a high beta 2-receptor density had relatively low levels of mRNA. This cellular heterogeneity may reflect differences in RNA stability or transcription rate in different lung cells. This approach opens up new options in the investigation of the regulation of pulmonary beta 2-receptor gene expression in health and disease.

Animals↗
PubMed1991

Distribution of endothelin-like immunoreactivity and mRNA in the developing and adult human lung.

Localization and characterization of endothelin-producing cells in the developing (fetal and postnatal) and adult human lung was investigated using the technics of immunocytochemistry and in situ hybridization. Immunoreactivity for endothelin was seen mainly in pulmonary endocrine cells of developing human lung. Immunoreactivity was also seen in the airway epithelium in fewer cases (about 50%) of human adults. In situ hybridization with 35S- or 32P-labeled RNA probes complementary to endothelin-1, -2, and -3, showed that endothelin mRNAs were expressed in a number of cells that were in similar sites to endocrine cells. Immunocytochemistry and in situ hybridization employed on pairs of reverse-face serial sections showed the presence of endothelin immunoreactivity and mRNAs in the same endocrine cell. Correlative studies revealed that endothelin is co-localized with general endocrine markers (synaptophysin, chromogranin, protein gene product 9.5) and regulatory peptides (e.g., gastrin-releasing peptide). The density (cells/mm2) of endocrine cells containing immunoreactivity or mRNAs was highest during fetal life and started to decline before birth, and was minimal in adults. Endothelin-like immunoreactivity and mRNAs were also expressed in endothelial cells. From these results, it is concluded that endothelin is synthesized in endocrine cells of human lung and the change of developmental expression of this peptide suggests it may play a part in growth regulation in addition to its putative vasoconstrictor role in human lung.

Adult↗
PubMed1990

Expression of gastrin-releasing peptide (human bombesin) gene in large cell undifferentiated carcinoma of the lung.

Production of the growth factor gastrin-releasing peptide (GRP) or human bombesin has been shown to be a feature of neuroendocrine tumours of the lung, particularly small cell carcinoma, and is possibly responsible for the characteristically rapid growth of this tumour. Large cell undifferentiated carcinoma of the lung (LCC) is also characterized by rapid growth and there is increasing evidence that some LCCs exhibit neuroendocrine differentiation. We therefore investigated GRP/bombesin immunoreactivity and the expression of GRP gene in ten LCCs. Histologically, all were composed of large cells with abundant cytoplasm, open nuclei, and prominent nucleoli, and there was no evidence of squamous, glandular, or neuroendocrine differentiation. At the ultrastructural level, most showed squamous or glandular differentiation but none contained neuroendocrine granules. None of the tumours showed immunoreactivity for GRP/bombesin but seven of the ten showed a focal hybridization signal when treated with 32P-labelled GRP cRNA probes, indicating the presence of GRP mRNA. This was confirmed by northern blot analysis. This study shows for the first time that GRP gene is expressed in LCC. The production of GRP may contribute to the aggressive behaviour of LCC.

Bombesin↗
PubMed1990

Detection of endothelin immunoreactivity and mRNA in pulmonary tumours.

Paraffin sections of 66 surgically resected lung tumours were immunostained with antisera to human endothelin-1 and to the C-terminal peptide of big endothelin. With both antisera, strong immunoreactivity was demonstrated in 11 of 15 squamous cell carcinomas and 11 of 16 adenocarcinomas. Focal immunoreactivity was seen in small cell carcinoma (2/12), large cell carcinoma (2/5), and carcinoid tumours (2/11). Four lymphomas and three sarcomas did not show endothelin immunoreactivity. Cryostat sections of 22 of the 66 tumours were hybridized with radiolabelled complementary RNA probes prepared from the 3' non-coding region of endothelin-1 cDNA, and the chromosomal genes encoding endothelin-2 and -3. In situ hybridization demonstrated the presence of endothelin mRNAs in 4 of 7 squamous cell carcinomas and in 5 of 8 adenocarcinomas, in a pattern similar to that shown by immunocytochemistry. No hybridization signals were obtained from the other types of tumours. In lung tissue adjacent to the tumours, endothelin-like immunoreactivity and mRNA were detected in pulmonary endocrine cells and, in some cases, other epithelial cells, and in alveolar capillary endothelial cells. This study demonstrates the expression of endothelin in a number of pulmonary tumours and suggests a possible role for this peptide in the growth and/or differentiation of these tumours.

Adenocarcinoma↗
PubMed1989

Expression of tachykinins by ileal and lung carcinoid tumors assessed by combined in situ hybridization, immunocytochemistry, and radioimmunoassay.

Mid-gut carcinoid tumors have been shown to produce substance P, a tachykinin. A recent addition to this family of peptides is neurokinin A which is cleaved from the same precursor as substance P; beta-pre-pro-tachykinin. The authors have examined mid-gut and pulmonary carcinoid tumors for the presence of the two tachykinins, using immunocytochemical study and radioimmunoassay, and have applied the techniques of in situ hybridization and Northern blot analysis to investigate the expression of mRNA for beta-pre-pro-tachykinin. All gut tumors (n = 8) and three of the six lung tumors examined were found by immunocytochemical study to contain both tachykinins or neurokinin A alone. Chromatographic analysis of tumor extracts suggests that this peptide is being detected as a separate molecule and/or as the C-terminal portion of a larger, uncleaved form. Three of the cases positive for tachykinins showed no detectable serotonin immunoreactivity. Strong hybridization signals for beta-pre-pro-tachykinin mRNA were seen in all but one of the cases studied which contained tachykinin immunoreactivity. Intact mRNA and positive hybridization was found by Northern blot analysis in two mid-gut tumors. Concentrations of tachykinins were found by radioimmunoassay to be higher in mid-gut tumors (substance P 27.2 +/- 19.7 pmol/g; neurokinin A 31.8 +/- 24.2 pmol/g; mean +/- SEM, n = 5) than in lung cases (substance P mean 0.8, range 0.5-1.0 pmol/g; neurokinin A mean 11.0, range 10.0-12.0 pmol/g; n = 3). These results show that mid-gut and pulmonary carcinoid tumors produce tachykinins, which are detected, in some cases, where no serotonin immunoreactivity can be found, possibly because of a high rate of amine secretion. Screening for tachykinins may prove to be a useful diagnostic adjunct for these tumors.

Blotting, Northern↗