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Biomedical subjects

A Mathai

Publications and source records attributed to A Mathai.

At least 37 records · Page 2Linked to original sources
PubMed1991

Isolation of two antigens from the culture filtrates of Mycobacterium tuberculosis and their applications in the laboratory diagnosis of the tuberculous meningitis.

Two antigens were isolated from the culture filtrates of H37Ra Mycobacterium tuberculosis by immunoabsorbent affinity chromatography, M. tuberculosis antigen 5 and immunoabsorbent affinity column-purified antigen (IAP). The potential application of these two mycobacterial antigens in the laboratory diagnosis of tuberculous meningitis was evaluated by indirect enzyme-linked immunoabsorbent assay in cerebrospinal fluid specimens. IAP antigen was more sensitive than antigen 5, although antigen 5 was more specific than IAP antigen in detecting tuberculous aetiology. Technical aspects of immunoabsorbent affinity chromatography have been highlighted in this study.

Antigens, Bacterial↗
PubMed1991

Rapid diagnosis of tuberculous meningitis with a dot enzyme immunoassay to detect antibody in cerebrospinal fluid.

A simple dot enzyme immunoassay (Dot-EIA) was carried out to detect antibody to Mycobacterium tuberculosis antigen 5 in cerebrospinal fluid (CSF) specimens from 40 patients with a clinical diagnosis of tuberculous meningitis (TBM). The assay gave a positive reaction in all ten patients with culture proven TBM. In 30 culture negative patients with TBM, the assay was positive at a titre of 1:16 in 18 patients. In 40 patients with non-tuberculous neurological diseases (control group) the assay was negative at a titre of 1:16. The Dot-EIA had an overall sensitivity of 70% and a specificity of 100% in the diagnosis of TBM. This assay could be used as a rapid screening test to establish the diagnosis of TBM, particularly in patients in whom bacteriological investigations for Mycobacterium tuberculosis in CSF specimens are negative.

Adolescent↗
PubMed1991

Detection of Mycobacterium tuberculosis antigen 5 in cerebrospinal fluid by inhibition ELISA and its diagnostic potential in tuberculous meningitis.

Inhibition ELISA was used to quantitate Mycobacterium tuberculosis antigen 5 in cerebrospinal fluid (CSF) specimens of 40 patients with a clinical diagnosis of tuberculous meningitis. In all 10 culture-proven patients, the assay was positive; in 30 culture-negative patients, the assay yielded positive results for 21. CSF antigen 5 concentrations ranged from 9 to 82 ng/ml (mean +/- SD, 45.5 +/- 6.2). In 40 patients with nontuberculous neurologic diseases, mean concentration was 1.45 ng/ml. Thus, inhibition ELISA for the detection of M. tuberculosis antigen 5 in CSF has definite diagnostic potential during the active phase of the disease and should be a routine diagnostic test, particularly when bacteriologic cultures in CSF are negative for M. tuberculosis.

Adolescent↗
PubMed1991

A dot-immunobinding assay for the laboratory diagnosis of tuberculous meningitis and its comparison with enzyme-linked immunosorbent assay.

In an attempt to establish an alternative to standard bacteriological methods in the laboratory diagnosis of tuberculous meningitis (TBM), a simple dot-immunobinding assay (Dot-Iba) was standardized to detect Mycobacterium tuberculosis antigen 5 and antimycobacterial antibody in cerebrospinal fluid (CSF) specimens of patients with TBM. Sensitivity and specificity of Dot-Iba was compared with conventional enzyme-linked immunosorbent assay (ELISA) and standard bacteriological techniques. The Dot-Iba showed excellent correlation with indirect ELISA for the detection of antimycobacterial antibody in CSF and showed 60% sensitivity and 100% specificity in culture-negative patients with TBM. However Dot-Iba was less sensitive for the detection of antigen 5 in CSFs and showed false negative results (60%) in culture-positive patients with TBM.

Antibodies, Bacterial↗
PubMed1991

Immunohistochemical demonstration of mycobacterial antigens in intracranial tuberculoma.

Mycobacterial antigens have been demonstrated immunohistochemically in the paraffin sections of 10 intracranial tuberculous granulomas and the results were compared with the detection of acid fast bacilli by conventional Ziehl-Neelsen method. In none of the 10 specimens, acid fast bacilli were demonstrated while mycobacterial antigens were characterised as diffusely staining granular brownish-pink material within the cytoplasm of giant cells and macrophages. In 14 specimens of granulomatous lesions due to non-tuberculous aetiology, immunohistochemical stains were negative for mycobacterial antigen. Thus demonstration of mycobacterial antigen will be not only useful in establishing mycobacterial aetiology of a caseating intracranial granuloma but also can be used as an alternative method to the conventional Ziehl-Neelsen method.

Antigens, Bacterial↗
PubMed1991

Humoral immune reactions in tuberculous meningitis.

Humoral immune reactions as reflected in sera and cerebrospinal fluid (CSF) of 50 patients with Tuberculous meningitis (TBM) were studied. CSFs and sera from 50 patients with nontuberculous neurological diseases were selected as controls. CSFs of patients with TBM showed high titres of circulating antimycobacterial antibodies than in nontuberculous subjects. The CSF-IgG index is significantly higher in patients with TBM. Humoral immune reaction could be applied in the laboratory diagnosis of TBM, particularly when repeated bacteriological methods are negative for M. tuberculosis in CSFs.

Antibody Formation↗
PubMed1991

Correlation between culture of Mycobacterium tuberculosis and antimycobacterial antibody in lumbar, ventricular and cisternal cerebrospinal fluids of patients with tuberculous meningitis.

In this study positive culture for M. tuberculosis were obtained, 20% in lumbar cerebrospinal fluid (CSF), 75% in ventricular CSF and 87.5% in cisternal CSFs of patients with tuberculous meningitis. Low culture positivity in lumbar CSF is due to the low density of circulating tubercle bacilli in lumbar CSF than in cisternal or ventricular CSFs. However antimycobacterial antibody in lumbar, cisternal and ventricular CSFs circulate in significant titres and are not statistically different from one another. Since specimens of CSF can not be obtained from cisternal or ventricular routes for the routine bacteriological investigations in patients with tuberculous meningitis, detection of antimycobacterial antibody of M. tuberculosis antigen 5 in lumbar CSF by an indirect ELISA may be considered as an aid for the diagnosis of tuberculous meningitis, particularly when repeated CSF cultures are negative for M. tuberculosis.

Antibodies, Bacterial↗
PubMed1991

Circulating immune complexes in cerebrospinal fluid of patients with tuberculous meningitis.

Circulating immune complexes (ICs) were isolated from cerebrospinal fluids (CSFs) of patients with tuberculous meningitis (TBM), non-tuberculous neurological diseases by a polyethylene glycol (PEG) precipitation method. Mycobacterium tuberculosis antigen 5 was detected in CICs of 30% patients with TBM, by sandwich ELISA. CIC level decreases during antituberculosis chemotherapy and therefore its detection can provide a method to monitor the therapeutic schedule in patients with TBM.

Adolescent↗
PubMed1991

Potential application of dot-immunobinding assay as a rapid diagnostic test in tuberculous meningitis.

A simple dot-immunobinding assay (Dot-Iba) in nitrocellulose paper was developed for the detection of specific IgG antibody to Mycobacterium tuberculosis antigen 5 and mycobacterial antigen in cerebrospinal fluid of patients with tuberculous meningitis (TBM). The assay gave 77.1% sensitivity for the detection of IgG antibody to M. tuberculosis antigen 5 and 48.6% sensitivity for the detection of mycobacterial antigen in patients with TBM.

Adolescent↗
PubMed1991

Rapid serodiagnostic test for pulmonary tuberculosis.

Immune complexes (ICs) were isolated from sera of patients with pulmonary tuberculosis (PT), non-tuberculous pulmonary diseases and healthy control subjects by polyethylene glycol (PEG) precipitation method. Specific mycobacterial antibody in ICs was tested against an affinity purified mycobacterial antigen by counter-current immunoelectrophoresis (CIE). The results show that specific mycobacterial antibodies are present only in ICs of patients with PT (70%). Therefore CIE could be used as a simple and rapid serodiagnostic test in patients with PT, particularly when bacteriological methods in sputum specimens are negative for Mycobacterium tuberculosis. CIE has several operational advantages over ELISA and best suited to laboratories with limited resources.

Counterimmunoelectrophoresis↗
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↗