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Biomedical subjects

S K Acharya

Publications and source records attributed to S K Acharya.

At least 91 records · Page 5Linked to original sources

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.

Antibodies, Anti-Idiotypic↗

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.

Dysentery, Amebic↗

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.

Enzyme-Linked Immunosorbent Assay↗

Viral diseases involving the liver.

Even though HAV, HBV and HNANB viruses are responsible for most of the viral hepatitis cases, many other viruses have been reported to cause hepatic injury. These viruses may involve the liver, either as part of a systemic illness (e.g. EBV, CMV, HSV) or as the primary target organ (e.g. yellow fever virus, Lassa fever virus, Ebola virus). Clinically overt hepatocellular dysfunction is rare in such viral infections. Biochemical disturbance of hepatic functions shown, for example, by rises in AST and ALT, is a frequent event and indicates hepatic damage. Morphological changes of the liver include varying degrees of hepatic necrosis with a paucity of inflammatory activities. Intranuclear or cytoplasmic inclusion bodies may be characteristic findings in these diseases. Laboratory diagnosis depends upon serology and liver histology. Treatment is still largely supportive in most of these diseases, although recent trials of antiviral agents show promise against some viruses. Chronic sequelae, such as cirrhosis or hepatocellular cancer, are not encountered. More work is needed to elucidate the pathogenesis of hepatic injury in these illnesses.

Hemorrhagic Fevers, Viral↗

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).

Carrier State↗

Bedside ultrasonography. A low-cost definitive diagnostic procedure in obstructive jaundice.

We evaluated real-time ultrasonography carried out by gastroenterologists for its diagnostic accuracy in 89 patients with obstructive jaundice. The positive predictive values for the site and nature of the obstruction were 94.3 and 89.9%, respectively. The advanced stage of disease in our patients and the clinical background of the investigators may have contributed to the high diagnostic accuracy of ultrasonography in this study. Nevertheless, we recommend that gastroenterologists themselves perform bedside ultrasonography for a definitive diagnosis in patients with obstructive jaundice. The high degree of precision achieved by ultrasound in our setting makes more expensive investigations unnecessary as routine procedures.

Cholestasis, Extrahepatic↗

Acute hepatic failure due to Plasmodium falciparum liver injury.

Nine patients with acute liver failure due to Plasmodium falciparum liver injury admitted to the Rajgarhia Liver Unit of the All-India Institute of Medical Sciences during 1982-84 are presented. The liver was palpable in all the patients, and eight had splenomegaly. Investigations revealed mild to moderate abnormality in liver function tests. All were negative for the markers of acute infection due to hepatitis A and B viruses. Blood film examination showed P. falciparum alone in seven and along with P. vivax in the remaining two patients. Liver histology, which was identical in all eight patients where liver biopsy was done, showed centrizonal necrosis and hyperplastic Kupffer cells loaded with malarial pigment. All the patients recovered with specific anti-malarial and supportive treatment. Our observations suggest that malaria due to P. falciparum may present as jaundice and encephalopathy which stimulates acute hepatic failure due to fulminant hepatitis.

Acute Disease↗

Sonographic appearances and percutaneous management of primary tuberculous liver abscess.

Primary tuberculous liver abscesses are rare. We report on 3 patients who presented with a nonresolving abscess in the liver. Clinical presentation and sonographic findings in each case were nonspecific. A diagnosis of tuberculosis was established with microbiologic examination of pus in 2 cases and examination of an excised abscess wall in 1 case. Needle aspiration (1 patient) and short-term (72 hours) catheter drainage (1 patient) were unsuccessful, and surgical excision was required in these patients. In the third patient, continuous catheter drainage over 18 days resulted in cure, indicating that long-term catheter drainage with antituberculous chemotherapy may be a viable alternative to surgery in the management of primary tuberculous liver abscess.

Adolescent↗