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Biomedical subjects

Y R Mahida

Publications and source records attributed to Y R Mahida.

At least 73 records · Page 4Linked to original sources
PubMed1991

Aspirin-induced gastric mucosal damage: prevention by enteric-coating and relation to prostaglandin synthesis.

1. Gastric damage induced by low-dose aspirin and the protective effect of enteric-coating was assessed in healthy volunteers in a double-blind placebo-controlled cross-over trial using Latin square design. Each was administered placebo, plain aspirin 300 mg daily, plain aspirin 600 mg four times daily, enteric-coated aspirin 300 mg daily, or enteric-coated aspirin 600 mg four times daily for 5 days. Gastric damage was assessed endoscopically, and gastric mucosal bleeding measured. 2. Aspirin 300 mg daily and 600 mg four times daily caused significant increases in gastric injury compared with placebo. Gastric mucosal bleeding was significantly more with the high dose, with a trend towards increased gastric erosions, compared with the low dose. 3. Enteric-coating of aspirin eliminated the injury caused by low dose aspirin and substantially reduced that caused by the higher dose. 4. All dosages and formulations caused similar inhibition of gastric mucosal prostaglandin E2 synthesis. 5. Serum thromboxane levels were suppressed equally with plain and enteric-coated aspirin. 6. In this short-term study in healthy volunteers, gastric toxicity from aspirin was largely topical, independent of inhibition of prostaglandin synthesis, and could be virtually eliminated by the use of an enteric-coated preparation.

Adult↗
PubMed1991

5-Aminosalicylic acid is a potent inhibitor of interleukin 1 beta production in organ culture of colonic biopsy specimens from patients with inflammatory bowel disease.

Interleukin 1 beta in biopsy specimens from inflamed colonic mucosa of patients with active inflammatory bowel disease was studied. Compared with normal colonic mucosal biopsy specimens, a significantly greater amount of interleukin 1 beta was present in rectal mucosa before (median (range) 4.3 (2.0-11.8) v 119.2 (30.1-286.8) pg/mg; p less than 0.01) and produced during organ culture (39.1 (9.4-106.8) v 97.6 (28.2-991.6) pg/mg; p less than 0.01). Values of interleukin 1 beta after culture correlated with concentrations of thromboxane B2. Organ culture of inflamed biopsy specimens in the presence of 5 aminosalicylic acid and dexamethasone reduced the amount of interleukin 1 beta detected. At the doses studied, 5 aminosalicylic acid also reduced the amount of leukotriene B4 detected after culture.

Adult↗
PubMed1991

High circulating concentrations of interleukin-6 in active Crohn's disease but not ulcerative colitis.

Peripheral venous plasma concentrations of interleukin-6 were studied in 21 patients with active Crohn's disease, 20 patients with ulcerative colitis, and 16 control subjects. Interleukin-6 was detected in the plasma of 18 of 21 patients with Crohn's disease (median 47 (range less than 20-250) pg/ml) but in only two with ulcerative colitis and two control subjects. In the patients with Crohn's disease there was a significant negative correlation between the plasma interleukin-6 and the serum albumin concentrations. In eight patients with Crohn's disease and five patients with ulcerative colitis undergoing resection plasma from peripheral circulation and mesenteric vein draining diseased intestine was studied. Interleukin-6 was detected in seven of eight peripheral and mesenteric samples from the patients with Crohn's disease but was not detected in any of the samples from the patients with ulcerative colitis. There was no significant difference between mesenteric and peripheral samples in the concentrations of interleukin-6.

Adolescent↗
PubMed1991

Coexpression of CD4 and CD8 on peripheral blood T cells and lamina propria T cells in inflammatory bowel disease by two colour immunofluorescence and flow cytometric analysis.

Using two colour immunofluorescence with fluorescein isothiocyanate and phycoerythrin labelled monoclonal antibodies and multiparameter flow cytometry, we investigated the coexpression of CD4 and CD8 antigens on peripheral blood lymphocytes and lamina propria lymphocytes of patients with ulcerative colitis and Crohn's disease and normal control subjects. Both the absolute number and the proportion of peripheral blood CD4+, CD8+ cells in inflammatory bowel disease were small but significantly increased compared with those in normal control subjects. Peripheral blood lymphocytes activated with phytohaemagglutinin showed appreciably increased coexpression of CD4+, CD8+. These CD4, CD8 positive cells were large and granular. Thus the increased number of peripheral blood CD4+, CD8+ cells in inflammatory bowel disease suggests that chronic immune activation occurs not only in the active state of the disease but also in remission. The proportion of CD4+, CD8+ cells in the lamina propria was greater than in peripheral blood in normal subjects, suggesting chronic immune stimulation of the local immune system. This was also seen in patients with Crohn's disease or inactive ulcerative colitis. The proportion of CD4+, CD8+ cells was, however, significantly less in the lamina propria of patients with active ulcerative colitis. Whether this implies a possible defect in mucosal immunoregulation in active ulcerative colitis cannot be determined from these results.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1990

Effect of human intestinal macrophages on immunoglobulin production by human intestinal mononuclear cells isolated from patients with inflammatory bowel disease.

The effect of macrophages on spontaneous immunoglobulin production by isolated human intestinal mononuclear cells (MNC) is unknown. Depletion of macrophages by adherence to fibronectin or by panning with macrophage-specific monoclonal antibody 3C10 lead to a significant reduction in IgA. IgG and IgM production by intestinal MNC from both normal (n = 10) and inflammatory bowel disease (IBD) (n = 13) mucosa. The reduction in immunoglobulin produced by macrophage-depleted intestinal MNC was greater in IBD patients than in normal controls. There was a significant correlation (r = 0.816, P less than 0.001) between the percentage of macrophages depleted by panning with 3C10 and the reduction in IgG produced by macrophage-depleted intestinal MNC. Addition of either fibronectin-adherent cells or the supernatant from these macrophage-enriched cells enhanced immunoglobulin production in a dose-dependent fashion. A greater increase in IgG production by macrophage-depleted cells was seen when cultured with supernatant from inflamed IBD mucosal cells, compared with that from normal mucosal cells. The soluble factor(s) responsible in the supernatant was acid and heat susceptible but was not affected by freezing and thawing. Addition of recombinant human interleukin-1 beta or human interferon-gamma to cell cultures did not influence immunoglobulin production. Thus, human intestinal macrophages enhance spontaneous immunoglobulin production by isolated intestinal MNC by secreting soluble factor(s) which remain to be fully characterized.

Cell Communication↗
PubMed1990

Plasma and tissue interleukin-2 receptor levels in inflammatory bowel disease.

Plasma and tissue interleukin-2 receptor (IL-2R) levels were determined in patients with active ulcerative colitis and Crohn's disease. Compared with healthy controls (median 440 U/ml; range 240-900), significantly higher levels of plasma IL-2R were present in patients with active ulcerative colitis (median 1180 U/ml; range 580-7150; P less than 0.002) and Crohn's disease (median 1340 U/ml; range 480-9000; P less than 0.002). Compared with other laboratory parameters, plasma IL-2R levels were related most closely to clinical score of disease activity in Crohn's disease. Plasma IL-2R levels also reflected the clinical course and may provide a more accurate assessment of disease activity in Crohn's disease. In plasma of patients undergoing intestinal resection of active inflammatory bowel disease, raised levels of IL-2R were present in samples from mesenteric vein (draining inflamed intestine) compared with those from peripheral vein. In tissue homogenates of colonic biopsies, significantly higher levels of IL-2R were present in specimens from colons with active ulcerative colitis compared with healthy controls (median 230.2, range 20.7-581.5 versus 77.9, range 34.2-291.3; P less than 0.02).

Biopsy↗
PubMed1990

Slow-release 5-amino-salicylic acid (Pentasa) for the treatment of active Crohn's disease.

A double-blind, placebo-controlled trial of a slow-release preparation of 5-amino-salicylic acid (Pentasa) has been performed in 40 patients with active Crohn's disease. Over a 6-week period, Pentasa (1.5 g daily) was no different to the dummy tablet in terms of clinical activity (Harvey-Bradshaw Index) or laboratory indicators of inflammation. No serious adverse reactions occurred.

Adult↗
PubMed1989

Respiratory burst activity of intestinal macrophages in normal and inflammatory bowel disease.

Macrophages isolated from normal mucosa (greater than 5 cm from tumour) and inflamed mucosa (from patients with inflammatory bowel disease) of colon and ileum were studied for their ability to undergo a respiratory burst as assessed by reduction of nitroblue tetrazolium to formazan. Using phorbol myristate acetate (PMA) and opsonised zymosan as triggers, only a minority (median: 8% for zymosan and 9% for PMA) of macrophages isolated from normal colonic mucosa demonstrated release of oxygen radicals. In contrast, a significantly greater (median: 17% for zymosan and 45% for PMA) proportion of macrophages isolated from inflamed colonic mucosa were able to undergo respiratory burst. Studies with normal and inflamed ileum showed similar results. Stimulation of macrophages isolated from normal colon with interferon-gamma produced only a small increase in the proportion of cells showing release of oxygen radicals. We conclude that the respiratory burst capacity of majority of macrophages isolated from normal colon and ileum is downregulated and a greater proportion of macrophages isolated from inflamed colon and ileum are able to undergo a respiratory burst.

Adolescent↗
PubMed1989

Macrophage subpopulations in lamina propria of normal and inflamed colon and terminal ileum.

The aim of this study was to characterise human intestinal macrophages in normal and inflamed ileum and colon. Immunoperoxidase staining with a panel of monoclonal antibodies and histochemical staining for acid phosphatase and non-specific esterase was performed. In the superficial lamina propria, normal colonic macrophages were larger and more strongly positive for acid phosphatase and non-specific esterase than those in normal terminal ileum. There were more macrophages staining with monoclonal antibody RFD1 in the superficial lamina propria of the latter. Studies in inflammatory bowel disease tissue showed the presence of macrophages staining with monoclonal antibodies RFD9 and 3G8 which were rarely present in normal tissue and represented a different pattern from that seen in infectious colitis. Studies on isolated intestinal macrophages confirmed the findings in tissue sections. Subpopulations of intestinal macrophages are likely to have different functional roles. Phenotypic changes during inflammation may be induced by mediators of inflammation or may represent a recently recruited population of cells.

Adolescent↗
PubMed1989

Enhanced production of interleukin 1-beta by mononuclear cells isolated from mucosa with active ulcerative colitis of Crohn's disease.

IL1-beta production by mononuclear cells isolated from normal and active inflammatory bowel disease mucosa was studied. Significantly more IL1-beta was produced spontaneously by mononuclear cells from the inflamed mucosa compared with those from normal colonic mucosa (median 190 pg/ml (range 45-700) v 20 pg/ml (0-165)). Stimulation with lipopolysaccharide enhanced IL1-beta production by mononuclear cells from active inflammatory bowel disease mucosa but not those from normal mucosa. Depleting the mononuclear cells of macrophages, by panning with monoclonal antibody 3C10, reduced the amount of IL1-beta produced. Enhanced IL1-beta production from the inflamed mucosa may play an important role in the mediation of many inflammatory responses. The enhanced production appears to be the result of a recruited population of cells.

Cells, Cultured↗
PubMed1989

Mononuclear phagocyte system of human Peyer's patches: an immunohistochemical study using monoclonal antibodies.

Macrophages in sections of human terminal ileal Peyer's patches were studied using a panel of monoclonal antibodies. Germinal centre macrophages were large and strongly positive for acid phosphatase and stained with antibodies RFD1, RFD9, UCHM1 and other macrophage-specific monoclonal antibodies, but not RFD7. In the macrophages of the dome region there was heterogeneity of size and staining for acid phosphatase. The majority of the RFD1 positive cells in this region appeared to be macrophages. However, no RFD9- or RFD7-positive cells were present. By contrast, RFD7-positive but RFD9-negative macrophages were present in the lamina propria. In the interfollicular areas there were cells with a dendritic morphology which were strongly HLA-DR, HLA-DQ and RFD1-positive, but which did not stain with the other macrophage specific monoclonal antibodies or for acid phosphatase. Some macrophages and lymphocytes in the germinal centre and dome regions expressed interleukin 2 and transferrin receptors. These cells were not present in the adjacent lamina propria.

Acid Phosphatase↗
PubMed1989

Immunoglobulin production by isolated intestinal mononuclear cells from patients with ulcerative colitis and Crohn's disease.

We studied immunoglobulin production by isolated intestinal mononuclear cells from 25 patients with active inflammatory bowel disease (IBD) and 17 controls undergoing surgical resections for intestinal tumour or other disorders. Normal ileal intestinal mononuclear cells spontaneously produced greater amounts of IgA and IgM than did normal colon cells. In cells from patients with IBD there was a significantly reduced IgA production, but production of IgG was enhanced in both colon and ileum. The alteration in IgA and IgG production in IBD was confirmed by comparing the immunoglobulin production by mononuclear cells from inflamed with that from non-inflamed areas of mucosa in six patients with distal ulcerative colitis. The proportion of IgA-containing cells in isolated intestinal mononuclear cells from IBD mucosa was less than normal. However, the proportion of IgG-containing cells from IBD mucosa was not increased in isolated intestinal mononuclear cells although they produced more IgG than normal mucosal cells. Our study showed an altered pattern of immunoglobulin production by intestinal mononuclear cells isolated from patients with inflammatory bowel disease.

Adult↗
PubMed1988

Association of small intestinal diverticulosis with chronic pancreatitis leading to severe malabsorption. Report of three cases.

Three cases of chronic pancreatitis occurring in patients with small intestinal diverticulosis and bacterial overgrowth are reported. In two of the cases, pancreatic supplements were therapeutically beneficial (the third being unable to tolerate them). Two of the patients also developed diverticular perforation. The possible nature of the association between small intestinal diverticulosis and chronic pancreatitis is discussed.

Aged↗
PubMed1988

Characterization of antigen-presenting activity of intestinal mononuclear cells isolated from normal and inflammatory bowel disease colon and ileum.

Antigen-presenting activity in mononuclear cells, isolated from normal and inflamed human ileum and colon, has been characterized using allogeneic mixed lymphocyte reaction with resting T cells as responders. Greatest proliferation was induced by fibronectin-adherent (macrophage-enriched) cells, and least by fibronectin non-adherent (macrophage-depleted) cells and by mononuclear cells depleted of macrophages by panning with monoclonal antibody 3C10. When intestinal mononuclear cells and allogeneic T cells were incubated in large numbers, clusters were observed. These clusters contained cells with a dendritic morphology that were strongly HLA-D-positive and which also stained with macrophage-specific monoclonal antibodies 3C10, EMB11 and Y1/82A. These cells were closely associated with proliferating T cells. Studies comparing mononuclear cells isolated from normal and inflamed colonic mucosa suggest that the latter may have enhanced antigen-presenting capacity.

Antigen-Presenting Cells↗
PubMed1988

Macrophage and lymphocyte subpopulations in magnifying endoscopic lesions of Crohn's disease.

Using dye staining and a magnifying colonoscope, small lesions in the rectum of patients with Crohn's disease (which had otherwise appeared normal on sigmoidoscopy) can be detected. Subpopulations of macrophages and lymphocytes in the abnormal and adjacent normal areas of the rectum were studied using a panel of monoclonal antibodies. There was a distinct increase in RFD9+ and 3G8+ macrophages in the abnormal areas compared with the normal. The CD4:CD8 ratio of lymphocytes in the two areas remained unchanged.

Antibodies, Monoclonal↗