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Biomedical subjects

A Choudhary

Publications and source records attributed to A Choudhary.

29 records · Page 2Linked to original sources
PubMed1994

The immunodominant 38-kDa lipoprotein antigen of Mycobacterium tuberculosis is a phosphate-binding protein.

Several antigens of Mycobacterium tuberculosis have been identified by monoclonal antibodies and are being exploited in the development of improved vaccines and diagnostic reagents, but none has been linked to a specific function. Herein we report that the 38-kDa extracellular lipoprotein antigen, the most potent immunogen of the mycobacteria, is a phosphate-binding protein with features very similar to those of the well characterized periplasmic phosphate-binding protein of Escherichia coli which serves as an initial receptor for active transport. This is also the first report definitively linking a function of a binding protein anchored to a membrane and found in other than Gram-negative bacteria.

Amino Acid Sequence↗
PubMed1994

Crystallization and preliminary X-ray crystallographic analysis of the 38-kDa immunodominant antigen of Mycobacterium tuberculosis.

The 38-kDa lipoprotein is one of the most potent cell surface immunogens of Mycobacterium tuberculosis in antibody-and T cell-mediated reactions. Using a pure recombinant form of the protein, we have recently shown that it binds phosphate much like that of the phosphate-binding protein (M(r) = 34.4 kDa) that is localized in the periplasm of Escherichia coli and is involved as an initial receptor for active transport of phosphate. The purified 38-kDa protein has been crystallized in 2 forms that are suitable for high-resolution structural analyses. One form belongs to the monoclinic space group P2(1) with unit cell dimensions of a = 67.42 A, b = 113.38 A, c = 42.68 A, and beta = 108.53 degrees. The other is of orthorhombic space group P2(1)2(1)2 with a = 125.46 A, b = 72.27 A, and c = 73.43 A. Both crystal forms diffract to about 2 A resolution on a fine focus rotating anode.

Antigens, Bacterial↗
PubMed1994

Evaluation of diversified antigens for detection of Mycobacterium leprae antibodies from leprosy patients and contacts.

A comparative evaluation of diversified antigens in ELISA has been made for detection of M. leprae antibodies in the sera of leprosy patients and their contacts. Out of the four antigens, namely M. leprae sonicate (ML), phenolic glycolipid I (PGL-1), M. habana sonicate (MH) and its arabinomannan (AM), the cross reactive antigens (MH,AM) have comparatively detected more number of leprosy cases. Homologous antigens (ML, PGL-1) have lower detection level. Use of MH and AM for detection of mycobacterial antibodies have been discussed and advocated for epidemiological studies of leprosy/tuberculosis.

Adolescent↗
PubMed1991

Detection of M. leprae-specific antigens with dot-ELISA in urine and nasal samples from leprosy patients.

One-hundred-two urine and nasal samples collected from leprosy patients of different classifications of disease were studied for the presence of Mycobacterium leprae antigens, including phenolic glycolipid-I (PGL-I). Lipids were extracted from the urine samples, and nasal washings were concentrated and used as such in the dot-ELISA. Two types of primary antibodies, a polyclonal antibody obtained from lepromatous (LL) leprosy patients' pooled and absorbed sera and an anti-PGL-I monoclonal antibody, were used for the detection of M. leprae antigens from these samples. The polyclonal sera detected 23% to 36% of the paucibacillary (PB) and 100% of the multibacillary (MB) leprosy cases from the urine samples. Corresponding values for nasal detection were 10% to 18% for PB and 100% for MB cases. The monoclonal antibody against PGL-I could not detect tuberculoid (TT) leprosy cases. From the urine samples, however, 16% of the borderline tuberculoid (BT), 25% of the borderline (BB), 80% of the borderline lepromatous (BL), and 100% of the LL leprosy cases were detectable. It was interesting to note that PB, skin-smear negative cases were detectable from urine examination. The specificity and sensitivity of the test is discussed in relation to the crossreacting antigens.

Adolescent↗
PubMed1990

Portal hypertension therapy with oral propranolol. A short-term study.

Thirty patients were evaluated in a blind fashion to study the effect of oral propranolol on portal hypertension of varied aetiology. The dose of oral propranolol (administered to 15 patients) was adjusted to reduce the resting heart rate by approximately 25%. Splenic pulp pressure served as the parameter for portal pressure. A matched group of 15 control subjects on placebo was also studied. The mean portal pressure in the propranolol group fell from 3.49 to 2.69 kPa saline (P less than 0.001) as compared to the control group where the mean pressure increased from 3.57 to 3.63 kPa saline. The propranolol group showed improvement in clinical symptomatology with a significant reduction in body weight and abdominal girth in patients with ascites. A significant positive correlation (r = 0.78; p less than 0.007) was obtained between the fall in portal pressure and the initial levels. Thus, oral propranolol proved useful in the conservative management of portal hypertension of varied aetiology.

Administration, Oral↗
PubMed1988

Detection of leprosy antigenuria through DOT-ELISA.

Fifty-five samples of urine from different grades of leprosy patients and normal persons were processed for detection of PGL-1 antigen through DOT-ELISA on nitrocellulose paper strips using anti-human IgG horse raddish peroxidaseconjugate. About 66.6% of the paucibacillary and 100% of the multibacillary leprosy cases were detectable through this technique on the basis of differential colour development on the strips. Possibility of its use in the field conditions has been discussed.

Antigens, Bacterial↗
PubMedDate not supplied

A study of correlation between vitreous potassium level and post mortem interval.

Present study was undertaken to study the correlation of potassium level of vitreous humor with time since death. Vitreous was collected from 150 medicolegal autopsy cases between August 2000 to March 2001 in Bharatpur Hospital, Bharatpur, Chitwan, Nepal. There was a linear increase in vitreous potassium level with rise of postmortem interval. This indicates that rise in potassium levels after death has a strong correlation with the PMI.

Adult↗