Search PubMed⌕ Search

Biomedical subjects

A Mathai

Publications and source records attributed to A Mathai.

52 records · Page 3Linked to original sources
PubMed1990

Detection of mycobacterial antigen in cerebrospinal fluid: diagnostic and prognostic significance.

Inhibition enzyme-linked immunosorbent assay (ELISA) was standardised to quantitate circulating mycobacterial antigens in cerebrospinal fluid (CSF) specimens. Of the 40 patients with clinical diagnosis of tuberculous meningitis, the assay was found to be positive in 26 patients. In a control group of 42 patients with non-tuberculous neurological diseases the assay was negative. The assay showed a sensitivity of 65 and 100% specificity for tuberculous meningitis. In 8 patients with tuberculous meningitis receiving chemotherapy, multiple CSF examinations were subjected to this assay. The antigen concentration showed a gradual decrease between 3 and 4 weeks after the commencement of antituberculosis chemotherapy. There was a positive correlation between clinical recovery and antigen concentration. Detection of mycobacterial antigen in CSF specimen by inhibition ELISA has not only diagnostic utility but also could be applied to monitor antituberculosis chemotherapy in patients with tuberculous meningitis. The assay is reproducible and feasible for routine immunology laboratory. It also could be considered as a diagnostic aid when repeated bacteriological cultures are negative in CSF specimens of patients with tuberculous meningitis.

Antigens, Bacterial↗
PubMed1990

Correlation between culture of Mycobacterium tuberculosis and detection of mycobacterial antigens in cerebrospinal fluid of patients with tuberculous meningitis.

A retrospective study was done to correlate culture of Mycobacterium tuberculosis and detection of mycobacterial antigen in cerebrospinal fluid (CSF) by an inhibition enzyme-linked immunosorbent assay (ELISA). M. tuberculosis was cultured from CSF of 14 out of 70 patients with a clinical diagnosis of tuberculous meningitis (TBM). Mycobacterial antigens were demonstrated in CSF specimens by inhibition ELISA in all 14 culture-positive patients with antigen concentrations of 14.5-295 ng/ml (mean 158.8 ng/ml). Thus there was positive correlation between the detection of mycobacterial antigen and isolation of M. tuberculosis. Based on this observation, 56 CSF specimens from culture-negative patients with clinically diagnosed TBM were examined for mycobacterial antigen and the data were compared with those from culture positive patients. ELISA gave positive results in 38 specimens, with antigen levels of 12.5-280 ng/ml (mean 152.6 ng/ml). In 70 CSF specimens from patients with non-tuberculous neurological disease (control group), ELISA results were negative. Thus, detection of mycobacterial antigen in CSF specimens by inhibition ELISA had a specificity of 100% and a sensitivity of 67.8% for the diagnosis of TBM and is of potential value in the laboratory diagnosis of TBM.

Antigens, Bacterial↗
PubMed1990

Detection of mycobacterial antigen in cerebrospinal fluid in patients with chronic meningitis by inhibition enzyme linked immunosorbent assay.

In a retrospective study, cerebrospinal fluid (CSF) specimens from 50 patients of chronic meningitis were investigated for tuberculous etiology by inhibition enzyme-linked immunosorbent assay (ELISA). CSF specimens from 10 patients of tuberculous meningitis in whom Mycobacterium tuberculosis was isolated, formed the positive control group of this study. The assay yielded positive results in CSF specimens for mycobacterial antigens in 8 of the 50 patients of chronic meningitis. No false positive results were recorded in 50 patients of non-meningitic (negative control group) neurological diseases. Inhibition ELISA procedure described here is reproducible and had 100 per cent specificity for tuberculous etiology. This assay could be applied as a diagnostic tool for tuberculous etiology, particularly in patients of chronic meningitis in whom repeated CSF cultures for any microbial agents are negative.

Antigens, Bacterial↗
PubMed1990

Immunoelectrophoresis of mycobacterial antigens.

Polyvalent antiserum to culture filtrate of H37 Ra M. tuberculosis was raised in rabbits. Monospecific antiserum was raised against M. tuberculosis antigen-5, prepared from the culture filtrates by immunoabsorbent affinity chromatography. On immunoelectrophoresis, antigen-5 demonstrated single precipitin arc against polyvalent and monospecific antisera. The culture filtrate antigen demonstrated multiple precipitin arcs against polyvalent antiserum and single precipitin are against monospecific antiserum. Antigen-5 could be isolated and characterized from the culture filtrate of H37 Ra M. tuberculosis. Immunoelectrophoresis could be one of the method to characterize the mycobacterial antigens prepared in the laboratory.

Animals↗
PubMed1990

IgG antibody to Mycobacterium tuberculosis antigen-5 in cerebrospinal fluid and its diagnostic application in tuberculous meningitis.

IgG antibody to M. tuberculosis antigen-5 was detected by non-competitive ELISA in cerebrospinal fluid specimens (CSF), from 40 patients with clinical diagnosis of tuberculous meningitis and in 42 patients of non-tuberculous neurological diseases. The geometric mean antibody titer in CSF specimen for tuberculous and non-tuberculous groups were 156 and 8 respectively. The antibody titer in CSF specimens showed no correlation to IgG levels, tuberculin reactor status and duration of chemotherapy in patients with tuberculous meningitis. At a dilution end-point 1:40, the assay had a sensitivity of 84% and specificity of 92%. However at dilution end-point 1:80, the specificity of the assay could be increased to 100% but sensitivity of the assay decreased to 75%. IgG antibody detection against M. tuberculosis antigen-5 by non-competitive ELISA, described in this communication has potential application in the laboratory diagnosis of tuberculous meningitis, particularly in developing countries where the incidence and prevalence of tuberculous meningitis is still high. In culture-negative cases of tuberculous meningitis, non-competitive ELISA could be applied as an alternative diagnostic tool.

Antibodies, Bacterial↗
PubMed1990

ELISA of IgG antibody to Mycobacterium tuberculosis antigen-5, PPD in CSF in tuberculous meningitis patients.

IgG antibody to M. tuberculosis antigen-5 and tuberculin purified protein derivative (PPD) was measured by enzyme linked immunosorbent assay (ELISA) in cerebrospinal fluid (CSF) specimens of 55 patients with tuberculous meningitis (TBM) and 55 patients with non-tuberculous neurological diseases (control group). The geometric mean antibody titre in CSF specimens of TBM patients was 82.4 with antigen-5 and 96.5 with PPD. In the control group, the geometric mean antibody titres for these antigens in CSF specimens were 4.6 and 10.8 respectively. The antibody titres did not show any correlation with tuberculin reactor status, duration of chemotherapy and IgG levels in CSF specimens in patients with TBM. At dilution end point 1:80, specificity of the assay was 100 per cent with antigen-5 and sensitivity of the assay was 70.9 per cent. False positivity observed in the control group with PPD antigen could be eliminated in 1:80 dilution in the assay with antigen-5. Antigen-5 is more specific than PPD antigen for the diagnosis of tuberculous meningitis.

Antibodies, Bacterial↗
PubMed1989

Glycosaminoglycan (GAG) level and activities of certain enzymes of GAG metabolism in Culex quinquefasciatus and Setaria digitata.

Significant differences were observed in GAG metabolism of S. digitata and one of its intermediate vectors, C. quinquefasciatus. Distribution of different components such as hyaluronic acid, heparin-sulphate, chondroitin-4-sulphate, chondroitin-6-sulphate, dermatan sulphate and heparin was comparable in both. However, there were quantitative differences; the difference was marked in the activity of enzymes of GAG metabolism in presence and absence of diethylcarbamazine (DEC) a known antifilarial drug. While the activities of beta-galactosidase and beta-N-acetyl glucosaminidase of S. digitata systems showed an inhibition of 96.5 and 92.6% respectively, in the Culex systems they showed an inhibition of 93.3% and an activation of 18% respectively. The differences clearly indicate the existence of basic differences in GAG metabolism of vector and parasite.

Acetylglucosaminidase↗
PubMed1982

The role of hyaluronidase in experimental cryptococcal infections.

Cryptococcal infection established in adult male albino rats under experimental conditions produced minimal tissue response to the infection, probably owing to the presence of cryptococcal capsular polysaccharide. Following hyaluronidase administration in the active phases of experimental cryptococcal infection, we have observed characteristic histiocytic granulomatous transformation in cerebral as well as extracerebral lesions. It is postulated that hyaluronidase depolymerizes the capsular mucopolysaccharide of Cryptococcus neoformans and causes its lysis. As a consequence, cryptococcal yeasts that are devoid of their protective capsule and exposed to the host phagocytic system evoke a granulomatous response. Possible application of hyaluronidase as an adjuvant in the therapy of cryptococcal infections needs to be assessed.

Animals↗
PubMedDate not supplied

Diagnostic utility of polymerase chain reaction and immunohistochemical techniques for the laboratory diagnosis of intracranial tuberculoma.

In an attempt to establish a tuberculous etiology, polymerase chain reaction (PCR) and immunohistochemical (IHC) methods were undertaken in formalin-fixed paraffin sections of ten surgical specimens of intracranial tuberculoma. The control group included an equal number of intracranial fungal granuloma. Both PCR and IHC methods did not yield false-positive results in fungal granuloma. PCR was found to be less sensitive (60%) than IHC method (80%) in this study. IHC method definitely possesses several operational advantages over PCR and is more suited to laboratories in developing countries for establishing a tuberculous etiology particularly in those patients in whom the conventional bacteriological methods did not confirm the diagnosis of tuberculoma.

Adolescent↗