Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0024523 (malabsorption)
7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastrointestinal (GI) infections are frequent in AIDS patients. The frequency and type of opportunistic GI infections are exactly the same in homosexuals and heterosexuals. Diarrhoea is the usual sign of GI infection, and its mechanism seems to combine a secretory component and a malabsorption. Although a number of pathogens can be isolated, in many cases the diarrhoea cannot be explained by an infection or a lesion. The hypothesis of a primary HIV infection in the epithelium of the small bowel and colon has not been confirmed by immunofluorescence and molecular hybridization. The HIV virus has been found in the GI mucosa, but it was probably carried by the immune cells in general circulation (CD4 lymphocytes and macrophages) which subsequently colonize the chorion of the mucosa.
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PMID:[Diarrhea in AIDS. Group AIDS GIT]. 131 17

49 gay men confirmed to be infected with the human immunodeficiency virus (HIV) and 9 HIV seronegative gay men participated in a pilot study comparing clinical status and enteric parasite load with gastrointestinal structure, function and symptomatology. Cases included 16/49 (33%) men who were CDC stage II, 7/49 (14%) who were CDC stage III, and 26/49 (53%) who were CDC stage IV. The mean CD4-lymphocyte count was 476 +/- 199 (SD)/microliter. The prevalence of enteric parasitic flora was similar in HIV seropositive patients and controls. Seven cases had enteric infection with pathogenic agents including 3 patients with Entamoeba histolytica, and 4 patients with Giardia lamblia, one of whom also had cryptosporidiosis. Other cases were most frequently colonized with Blastocystis hominis (44%) and Endolimax nana (41%) regardless of the HIV clinical status. HIV seropositive patients with enteric parasitic colonization tended to have lower mean levels of serum IgA than cases without parasites. Duodenal morphometric mucosal changes demonstrated a significant decrease in the mean villous height (p < 0.01) with no elongation of the crypt depth in HIV-infected patients with and without diarrhea compared to controls. Despite gastrointestinal symptoms including diarrhea and weight loss being more prevalent in HIV infected individuals than controls, no correlations were found between the presence of particular enteric parasites, gastrointestinal symptomatology, the clinical HIV status of the CD4-lymphocyte count, the malabsorption of D-xylose or morphometric changes in the duodenum.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Absence of an association between enteric parasites in the manifestations and pathogenesis of HIV enteropathy in gay men. The GI/HIV Study Group. 136 Dec 41

Twenty-seven cases of primary peripheral T-cell lymphomas of the intestine (PTLI) were investigated. Seven patients had histories of malabsorption. The most frequent symptoms at presentation were weight loss, abdominal pain, and acute abdomen. The jejunum was the most common site of lymphoma and multifocal disease was found in 72% of the cases. Twenty-two patients (92%) presented with localized disease confined to the intestine and abdominal lymph nodes, only two patients had generalized disease. According to the pattern of lymphoma infiltration and the morphology of the uninvolved small intestinal mucosa, 21 cases were separated histologically into three categories; 1) enteropathy-associated T-cell lymphoma (EATCL, n = 9) showing predominant intramucosal lymphoma spread and villous atrophy of uninvolved mucosa with high density of intraepithelial lymphocytes (IEL), 2) EATCL-like lymphoma without enteropathy (EATCL-LLWE, n = 5) but with an infiltration pattern similar to EATCL, and 3) T-cell lymphoma without features of EATCL (Non-EATCL, n = 7). Distinctive features of EATCL were the high incidence of malabsorption states, multifocal intestinal disease in all cases, and the high frequency of intestinal recurrences. On frozen sections four of eight PTLI showed the phenotype CD3+ CD4- CD8- HML-1+, which is also expressed on a small subset of normal IEL. The morphologic and immunomorphologic findings suggest that the majority of PTLI is derived from mucosal T lymphocytes. This derivation may be responsible for certain biologic features, such as the preferential spread to and relapse of PTLI at small intestinal sites.
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PMID:Peripheral T-cell lymphomas of the intestine. 146

Enteropathy-associated T-cell lymphoma commonly presents with malabsorption, and debate continues as to whether adult-onset coeliac disease (CD) is itself a form of low-grade lymphoma. A 59-year-old man with adult-onset CD required resection of a segment of oedematous jejunum. Histological examination of this tissue revealed an intense intraepithelial lymphocytosis. Immunophenotypic (CD3-, CD4-, CD8-, CD34-, and CD45 RO-) and cytogenetic (deletion of the Y chromosome and chromosome 9) abnormalities were found, together with monoclonal T-cell-receptor gene rearrangements. Some patients with adult-onset CD may have low-grade lymphoma from the outset of their illness.
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PMID:Is adult-onset coeliac disease due to a low-grade lymphoma of intraepithelial T lymphocytes? 167 39

A prospective study of 60 consecutively admitted patients with HIV infection was performed to document the prevalence, etiology and manifestations of low serum vitamin B-12 in such patients. Low serum B-12 levels were found in 10 patients (16.7%). In 6, vitamin B-12 absorption was impaired and hog intrinsic factor addition did not improve it. Patients with low vitamin B-12 levels showed lower hemoglobin, leukocytes, lymphocytes, CD4 lymphocytes and CD4/CD8 lymphocyte ratio than HIV patients with physiological serum vitamin B-12 levels. However, bone marrow megaloblastosis was found in only 3 low vitamin B-12 patients and the deoxyuridine suppression test was pathological in only 1 case. In 7 patients, parenteral treatment was begun with variable response despite serum vitamin B-12 correction. In conclusion, low serum vitamin B-12 is often found in HIV-infected patients and it could be related to malabsorption, but clear megaloblastic abnormalities and treatment response could not be demonstrated. A decreased concentration of the serum binders due to disturbances in the leukocytes and related immunocompetent cell may play an additional role.
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PMID:Vitamin B-12 abnormalities in HIV-infected patients. 186 15

Newborns suffering from short bowel syndrome (SBS) after massive intestinal resection have numerous infectious complications, which may be due to immunoincompetence from the loss of gut-associated lymphoid tissue (GALT). This study examines the ontogeny of GALT in the rat with SBS. A total of 36 3-week-old rats were divided into two groups: I, sham operated (C, n = 16); and II (SBS, n = 20), with a 50% resection of small intestine with jejunoileostomy. At 4, 5, 6, and 10 weeks of age the animals were sacrificed and the GALT was assessed by video analysis and immunoperoxidase monoclonal antibodies, OX8 (CD8), W-3/25 (CD4), and MARA-2 (IgA). The data were expressed as positive staining lymphocytes per 10(4) microns2 (mean +/- SD). table; see text In the sham group there was an increase in all lymphocyte subsets over time. In the SBS group there was a rapid fall in OX8 and W-3/25 T-lymphocytes by 10 weeks, with no increase in IgA plasma cells at 6 and 10 weeks. This study demonstrates that in the massive bowel resection in the suckling rat decreases the T- and B-lymphocyte populations in the GALT. This lack of development may underlie the associated infectious complications and malabsorption in SBS.
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PMID:The ontogeny of the gut-associated lymphoid tissue in short bowel syndrome. 233 23

Deficiency of vitamin B12 is commonly reported in HIV-infected patients. We measured vitamin B12 levels in 36 HIV-infected patients with chronic diarrhea (> 3 stools/day for six weeks or more). Eight patients had an identifiable cause of diarrhea. Vitamin B12 levels were low in 39%. Sixteen of these patients were selected to undergo further testing, eight patients with low levels of vitamin B12 and eight with normal B12 levels. These 16 patients had both a stage II Schilling test and measurement of multiple serum D-xylose concentrations performed after both oral and intravenous doses of D-xylose. Integrated areas under the curves (AUC) for D-xylose concentration versus time were calculated for intravenous and oral doses, and D-xylose bioavailability was determined. Stage II Schilling tests were abnormal in 11 patients, (69%). D-Xylose bioavailability correlated closely with vitamin B12 absorption (r = 0.648, P < 0.01). Comparisons of mean values for CD4 count, serum albumin, Karnovsky score, six-month weight loss, 1-hr serum D-xylose levels and MCV failed to reveal a significant difference between those with and without abnormal serum vitamin B12 levels. These data indicate that below-normal levels of vitamin B12 are highly prevalent in HIV-infected patients with chronic diarrhea. Malabsorption of vitamin B12 occurs in the setting of an enteropathic process effecting both the proximal and distal small bowel. Since no risk factors for vitamin B12 deficiency could be identified, screening for vitamin B12 deficiency in HIV-infected patients with chronic diarrhea is strongly recommended.
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PMID:Malabsorption and deficiency of vitamin B12 in HIV-infected patients with chronic diarrhea. 792 36

Human intestinal lamina propria T cells have a low expression of the CD45RA antigen and a high expression of the CD45RO antigen. This phenotype is characteristic for memory T cells. In addition, T cells in the effector compartment of the mucosa bear surface antigens that are very rarely found in other sites of the immune system. Intestinal T cells also express functional IL-2 receptors, and IL-2 receptor alpha-chain mRNA, and are able to synthesize high amounts of IL-2. However, other markers of memory T cells, as CD29, are not expressed in high density in the lamina propria, indicating that lamina propria T cells differ from "classical" memory T cells. This is supported by functional studies in nonhuman primates infected rectally with Chlamydia trachomatis that show that lamina propria T cells do not proliferate after stimulation with antigen but rather provide helper function for immunoglobulin synthesis. These findings indicate a specific state of differentiation of lamina propria T cells that is adapted to the specific requirements in the gut. In inflammatory bowel disease (IBD) and in celiac disease, an increase in the number of CD25-positive activated T cells is found in involved mucosa. It has been shown that mucosal T-cell activation induces epithelial cell damage and mucosal transformation. Thus, a T cell-mediated damage may contribute to the pathogenesis of IBD. HIV-infected patients have a decreased number of CD4-positive T cells in the intestinal lamina propria. The number of CD25-positive activated T cells is also significantly decreased in the intestine compared to controls. Correlating with the presence of HIV-infected mononuclear cells in the mucosa, mucosal atrophy with hyporegeneration and enterocyte dysmaturation is observed. HIV might thus cause impairment and depletion of activated regulatory T cells in the intestinal lamina propria, which could lead not only to a breakdown of the mucosal immune barrier, resulting in a variety of opportunistic infections, but also to malabsorption, due to mucosal atrophy or enterocyte dysfunction. These findings indicate a close relationship between mucosal T cells and enterocyte proliferation and maturation.
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PMID:Cell differentiation and proliferation in the gastrointestinal tract with respect to the local immune system. 797 5

Intestinal function is poorly defined in patients with HIV infection. Absorptive capacity and intestinal permeability were assessed using 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose in 88 HIV infected patients and the findings were correlated with the degree of immunosuppression (CD4 counts), diarrhoea, wasting, intestinal pathogen status, and histomorphometric analysis of jejunal biopsy samples. Malabsorption of 3-O-methyl-D-glucose and D-xylose was prevalent in all groups of patients with AIDS but not in asymptomatic, well patients with HIV. Malabsorption correlated significantly (r = 0.34-0.56, p < 0.005) with the degree of immune suppression and with body mass index. Increased intestinal permeability was found in all subgroups of patients. The changes in absorption-permeability were of comparable severity to those found in patients with untreated coeliac disease. Jejunal histology, however, showed only mild changes in the villus height/crypt depth ratio as compared with subtotal villus atrophy in coeliac disease. Malabsorption and increased intestinal permeability are common in AIDS patients. Malabsorption, which has nutritional implications, relates more to immune suppression than jejunal morphological changes.
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PMID:Intestinal absorptive capacity, intestinal permeability and jejunal histology in HIV and their relation to diarrhoea. 854 36

Two adult cases of extranodal malignant lymphoma diffusely involving the intestinal wall are reported. Lymphoblastic lymphoma in case 1 (68-year-old male) and small lymphocytic lymphoma in case 2 (48-year-old male) were initially manifested as protein-losing enteropathy or malabsorption syndrome. In case 1, the patient died of massive ascites and intestinal bleeding 10 months after presentation. Autopsy revealed diffuse and extensive lymphomatous involvement of the small and large intestine, peritoneum and liver. The patient in case 2, showing low-grade diffuse lymphomatous invasion throughout the small bowel mucosa without involving other organs, is currently being followed up. Surface marker studies revealed previously undescribed phenotypes, such as CD4/CD8 double-positive blastoid T cells in case 1, and CD8-positive suppressor/killer T cells in case 2. T-cell receptor alpha/beta was expressed on the lymphoma cells in both cases. Epstein-Barr virus infection was not evident. The gut-associated nature of the T-lymphoma cells, possibly of extrathymic origin, is discussed.
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PMID:T-cell lymphomas diffusely involving the intestine: report of two rare cases. 876 87


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