Biomedical subjects
M Irshad
Publications and source records attributed to M Irshad.
Fibronectin in acute and subacute hepatic failure.
The mean plasma fibronectin (FN) concentrations in 30 patients with fulminant hepatic failure (FHF) and in 10 patients with subacute hepatic failure (SAHF) were 111.2 +/- 70 and 123.5 +/- 46.5 micrograms/ml, respectively, significantly lower than that of normal controls (362.0 +/- 69.2 micrograms/ml) and patients with uncomplicated viral hepatitis (320 +/- 58.5 micrograms/ml) (p less than 0.001). Plasma FN levels showed significant negative correlation with serum glutamic pyruvate transaminase values in the FHF group (p less than 0.02) and with prothrombin time in the SAHF group (p less than 0.02). Serial estimation of plasma FN showed that failure of FN levels to rise despite fresh plasma infusions indicates poor prognosis in these patients. The reduced availability of FN may be responsible for the impaired Kupffer cell function and consequent increased susceptibility to endotoxemia and the bacterial infections seen in these patients.
Serum alpha-feto protein in amoebic liver abscess.
Serum alpha-feto protein (AFP) levels were determined using a sensitive and specific ELISA technique in healthy persons (40), patients with amoebic liver abscess (ALA, 70) and hepatocellular carcinoma (HCC, 20). The AFP levels in normal persons ranged between 0 to 20 ng/ml. Most of ALA patients had AFP levels in the normal range; only a small proportion (14.3%) showed elevated levels (range 20-75 ng/ml). Sera from HCC patients had significantly high AFP values in the range of 25 to 340 ng/ml as compared to normal controls and ALA patients. An analysis of serial samples from 10 ALA patients in convalescent phase showed no difference in AFP level during acute and convalescent phase of infection.
A simple spot-test for circulating Entamoeba histolytica antigen-antibody complexes in patients with amoebic liver abscess.
An enzyme linked immunosorbent assay (ELISA) is described for the detection of E. histolytica immune complexes in serum. Antiamoebic antibody purified by affinity chromatography was used both to precoat strips of nitrocellulose membrane and as an enzyme carrier. These strips were incubated with samples of concentrated test serum and the enzyme conjugate. Following treatment with the peroxidase substrate 3-amino-9-ethylcarbazole the presence of E. histolytica antigens was visualized as red spots. Blocking of positive test sera with excess antibodies inhibited this reaction. Serum samples from 47 patients with amoebic liver abscess, 43 patients with other enteric diseases and 35 healthy controls were investigated. The spot test was positive in 75 per cent of patients with amoebic liver abscess, and in 12 per cent diseased controls whereas all the healthy controls were negative. The spot test is simple and sensitive and does not require prior separation of the immune complexes. The test is recommended as an aid to the diagnosis in patients suspected to have amoebic liver abscess.
Serological pattern of hepatitis B virus markers (HBsAg, anti-HBs, IgM anti-HBc and HBV specific DNA polymerase) in leprosy patients.
Sera of 134 lepromatous (LL/BL) and 57 tuberculoid (TT/BT) leprosy patients were analysed for four HBV markers. HBsAg was detected in 6.71% of lepromatous and 3.5% of tuberculoid sera. The per cent positivity of lepromatous and tuberculoid sera for anti-HBs antibodies was 30.59% and 35.08%, respectively. The positivity of normal sera for HBsAg and anti-HBs was 3.60% and 21.69%, respectively. The difference in the positivity of three groups of sera (lepromatous, tuberculoid and normal) for HBsAg or anti-HBs was not statistically significant. Anti-HBc (IgM) antibodies were detected in 6% of lepromatous sera. HBV-specific DNA-polymerase activity was found in 22.22% of HBsAg positive (but anti-HBc negative) sera, and 66.66% of anti-HBc positive (but HBsAg negative) sera. The pattern of acute HBV infection in leprosy patients followed the typical pattern prevalent in the normal population.
Role of immune serum globulin in post transfusion virus B infection.
Fifty four blood recipients were administered prophylactic immune serum globulin (31) or hepatitis B immune globulin (23) and followed up for six months. None of the patients developed either acute hepatitis B or HBsAg carrier state. However, 7 (14%) had anicteric self limiting non-B post-transfusion hepatitis. Twenty (40%) of the blood recipients developed anti-HBs during the follow up period suggesting either HBV exposure by subdetectable levels of HBsAg present either in blood or immunoglobulin preparation or due to passive transfer by administration of immunoglobulins.
Amebic liver abscess and circulating immune complexes of Entamoeba histolytica proteins.
An enzyme-linked immunosorbent assay (ELISA) has been developed to detect amebic antigen in polyethylene-glycol-precipitable circulating immune complexes. Seventy-nine percent of 191 patients with amebic liver abscesses and 46% of 26 Entamoeba histolytica cyst passers had positive tests. None of the samples from 43 apparently healthy controls, 8 patients with past amebic liver abscesses or 31 patients with Giardia lamblia infections were positive. One patient out of 32 with viral hepatitis and 1 patient out of 27 with intestinal tuberculosis had positive tests.
Prevalence of amoebic antibody in population affected by epidemic non-A, non-B hepatitis.
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An enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM anti-idiotypes directed against anti-HBs molecules.
A simple and specific enzyme-linked immunosorbent assay (ELISA) has been developed to detect circulating IgG and IgM anti-idiotypic antibodies directed against anti-HBs molecules using 96-well polyvinyl microtitre plates as the solid phase and HRPO-labelled goat anti-HBs as conjugate. Anti-idiotype reactions were observed in the supernatant portion after precipitation of immune complexes from sera with polyethylene glycol 6000 (PEG). Both IgG and IgM with anti-idiotype activity were detected concurrently in HBsAg-positive sera from HBV-infected patients and asymptomatic HBV carriers. Anti-idiotype activity was absent in HBsAg-negative sera from healthy persons, and in patients with non-A, non-B hepatitis and viral hepatitis A. However, such antibodies could be demonstrated in the sera of two out of eight HBsAg vaccine recipients negative for anti-HBs but in none of 11 recipients positive for anti-HBs after receiving a booster immunising dose of HBsAg vaccine. Those sera showing positive anti-idiotype reactions were free from rheumatoid factor and HBsAg/IgM or HBsAg/IgG complex activity. An analysis of anti-idiotype positive sera for anti-HBs, HBeAg and HBV-specific DNA-polymerase activity demonstrated these markers in 20%, 30% and 60% of cases, respectively. The presence of anti-idiotypic antibodies was presumed to permit a more active multiplication of hepatitis B virus.
Enzyme linked protein-A: an ELISA for detection of amoebic antibody.
Enzyme linked protein-A was used to develop an enzyme linked immunosorbent assay (ELISA) system for the detection of circulating antibodies to amoebic antigen. The specificity of protein-A to bind IgG only through Fc receptors, makes the test more specific for the detection of IgG antibodies to amoebic antigen. The ELISA system was used to detect amoebic antibody in control subjects (56), patients with amoebic liver abscess (79) and Entamoeba histolytica cyst-passers (10) and the results compared with those of indirect haemagglutination assay (IHA). The ELISA was more sensitive and detected 74.7% of cases with amoebic antibody in amoebic liver abscess compared with 66.7% detected by IHA. The test was more specific, sensitive and easy to perform and is recommended as a test of choice for the serological diagnosis of amoebic liver abscess.
Entamoeba histolytica: elevated nitroblue tetrazolium reduction activity in polymorphs during amoebic liver abscess.
Peripheral blood polymorphonuclear leucocytes (PMN) from patients with invasive amoebiasis, i.e. amoebic liver abscess (ALA) and acute amoebic dysentery, showed marked elevation of nitroblue tetrazolium dye (NBT) reduction. This dramatic change was not observed in PMN from patients with non-invasive amoebiasis, i.e. non-suppurative hepatic amoebiasis, or in asymptomatic Entamoeba histolytica cyst passers. A small number (12%) of patients with viral hepatitis displayed increased NBT reduction. 10 to 12 days after recovery following treatment, the majority (75%) of ALA patients failed to show increased NBT reduction. Our results suggest that the PMN-NBT reduction test could be useful as an aid to the diagnosis of ALA.
Studies on HBsAg binding with polymerised human serum albumin by ELISA.
A simple and sensitive ELISA was developed to characterize the interaction between polymerised human serum albumin (pHSA) and HBsAg, using pHSA-coated polyvinylmicrotitre plates as solid phase and anti-HBs-coupled HRPO as the conjugate. The interaction was found to be specific and dependent on the size of albumin polymer. pHSA-binding activity (pHSA-BA) was studied in both HBsAg-negative and HBsAg-positive sera from various liver diseases including acute viral hepatitis, fulminant hepatitis, cirrhosis of liver, chronic active hepatitis, and healthy HBsAg carriers. pHSA-BA was detected only in HBsAg-positive sera. Analysis of HBsAg-positive sera indicated pHSA-BA in high proportions of patients sera as compared to sera from healthy HBsAg carriers. pHSA-BA was detected both in the presence and absence of HBe markers, though the mean BA was relatively high in presence of HBeAg. The effect of human serum immunoglobulins (IgG, IgA, and IgM) on the BA was investigated and a correlation between pHSA-BA and HBsAg-IgM complex positivity in sera was established. Finally, the probable role of human serum IgM in facilitating the binding process was discussed.
Relation between HBsAg binding with polymerized human serum albumin and HBV replication.
The binding between hepatitis B surface antigen (HBsAg) and polymerized human serum albumin (poly-HSA) was studied in HBsAg-negative (25) and HBsAg-positive (92) sera by a sensitive enzyme-linked immunosorbent assay technique, and a correlation of binding activity was made with HBe-markers and hepatitis B virus-specific DNA polymerase. The binding could be detected only in HBsAg-positive sera and was found to be independent of the presence of HBe-markers and DNA polymerase activity. Further, binding was noted in significantly higher proportions of sera samples from the patient group compared with the healthy carrier group (p less than 0.01).
Alpha-2 macroglobulin: an additional marker for diagnosis of hepatocellular carcinoma.
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Immunological characterization of axenic Entamoeba histolytica related antigens.
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Serological studies of Mycobacterium tuberculosis infection in north Indian population.
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Enzyme linked protein-A: an ELISA for detection of IgG antibodies against Mycobacterium tuberculosis in intestinal tuberculosis.
Enzyme linked protein-A has been used to develop an enzyme-linked immunosorbent assay (ELISA) to detect circulating IgG antibodies to Mycobacterium tuberculosis. The specific binding of protein-A to IgG fractions through Fc receptors, makes the test more specific for detection of total IgG antibodies. The ELISA system has been used for detection of circulating antibodies to M. tuberculosis H37Ra in 22 patients with histologically proven intestinal tuberculosis and 88 healthy controls, in addition to 7 diseased controls. The ELISA has been found to be a sensitive test as it was positive in all 22 patients with intestinal tuberculosis. Its specificity was 85% in Indian controls and 97% in Norwegian controls. The test is easy to perform and may be recommended for the serological diagnosis of intestinal tuberculosis.
Determination of beta-amylase in presence of alpha-amylase.
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