Biomedical subjects

A Mathai

Publications and source records attributed to A Mathai.

At least 37 records · Page 2Linked to original sources

PubMed1994

Diagnosis of tuberculous meningitis by enzyme-linked immuno-sorbent assay (ELISA), using an affinity chromatography purified mycobacterial antigen.

Using an immunoabsorbent affinity chromatography, a mycobacterial antigen was isolated from culture filtrate of H37Ra Mycobacterium tuberculosis (MTB). The immunoabsorbents were prepared by coupling cynogen bromide-activated Sepharose-4B with human IgG antibody to MTB. Cerebrospinal fluids (CSF) from 10 culture positive, 30 culture negative patients with tuberculous meningitis (TBM) were assayed, for IgG antibody to this mycobacterial antigen by ELISA. CSFs from 50 patients with non-tuberculous neurological diseases were selected as control group. At a selected 'cut off' titre of 1:80, 21 out of 30 CSFs from culture negative patients gave positive results. No false negative result was observed in CSF from 10 culture positive patients with TBM. No false positive results were recorded in CSFs of 50 patients with non-tuberculous neurological diseases. Technical aspects involved in the isolation of this myobacterial antigen and its potential applications in the laboratory diagnosis of TBM have been emphasised in this study.

Antibodies, Bacterial↗

PubMed1993

Botulinum toxin in the treatment of paralytic strabismus and essential blepharospasm.

As an alternative to conventional medical and surgical modalities that have met little success in the treatment of paralytic strabismus and essential blepharospasm, we explored the use of botulinum toxin as a treatment of choice in these two disorders. We used botulinum toxin in three patients with paralytic strabismus and in nine patients with essential blepharospasm. In three patients with paralytic strabismus, the botulinum toxin was injected into the ipsilateral antagonist of the paralysed muscle. The preinjection deviations ranged from 18 to 60 prism diopters. Two of these three patients achieved orthotropia around the thirtieth day and thereafter maintained it. The third patient became orthotropic on the eighteenth day, but deviation recurred and therefore required another injection of toxin. In nine patients with essential blepharospasm, botulinum toxin was injected into the orbicularis oculi muscles. Both objective and subjective improvement occurred in all nine patients within seven days and the effect lasted 12 to 15 weeks. Further injection of the toxin produced extremely beneficial results. However, the only significant complication that we encountered in both groups of strabismus and blepharospasm was ptosis, which was usually partial and temporary. From our experience, we advocate the use of botulinum toxin in the treatment of essential blepharospasm.

Adult↗

PubMed1993

Correlation between the isolation of Mycobacterium tuberculosis and estimation of mycobacterial antigen in cisternal, ventricular and lumbar cerebrospinal fluids of patients with tuberculous meningitis.

In the study Mycobacterium tuberculosis was isolated in the cerebrospinal fluid (CSF) specimens of patients with tuberculous meningitis (TBM) by the conventional bacteriological technique. The isolation rate of M. tuberculosis was found to be 11.5% in lumbar, 75% in ventricular and 87.5% in cisternal CSFs. Low isolation rate of M. tuberculosis in lumbar CSF is due the low density of tubercle bacilli in lumbar CSF than in cisternal CSF. However M. tuberculosis antigen 5 is present in significant concentration in CSFs. The antigen concentration in CSF was estimated by an inhibition enzyme-linked immunosorbent assay (ELISA). Since CSF specimens can not be collected from ventricular or cisternal routes for the routine bacteriological investigations in patients with TBM, estimation of M. tuberculosis antigen 5 concentration in lumbar CSF by an inhibition ELISA may be considered as an adjunct in the laboratory diagnosis of TBM. This is particularly relevant in those patients in whom bacteriological methods fail to demonstrate M. tuberculosis in CSF specimens.

Antitubercular Agents↗

PubMed1993

Releasable suture technique for trabeculectomy.

We studied the effect of the releasable suture technique on immediate postoperative intraocular pressure (IOP). Nine eyes of nine patients with glaucoma had trabeculectomy with a releasable suture. In the six eyes that did not receive antimitotics, the suture was released by the fifth postoperative day; in the others suture release was delayed up to the fourteenth day. Of the nine patients, one had an acceptable postoperative IOP and did not need suture release; in another the suture broke and could not be released. In the remaining seven patients, the difference between the pre-release and post-release IOP was statistically significant (p < 0.001). The complications of this technique include failed suture release, subconjunctival hematoma and a distinctive "windshield wiper" keratopathy.

Corneal Diseases↗

PubMed1993

Immune complex levels and plasmapheresis in Guillain-Barré syndrome.

Circulating IC levels were assayed serially in 12 G.B.S. patients treated with PE and an attempt was made to predict the outcome of treatment, from the levels of circulating IC. It was found that there was no significant correlation between the levels of circulating IC and the outcome of treatment with PE, in G.B.S. patients.

Adolescent↗

PubMed1992

Diagnostic significance of circulating immune complexes in patients with pulmonary tuberculosis.

A polyethylene glycol (PEG) precipitation method was used to examine sera of patients with active pulmonary tuberculosis (PT), leprosy and non-tuberculous pulmonary diseases and of healthy control subjects for immune complexes (ICs). Mycobacterium tuberculosis antigen 5 was detected in the ICs in 80% of patients with PT by the indirect (sandwich) enzyme-linked immunosorbent assay (ELISA). Detection of mycobacterial antigen in ICs has diagnostic potential as an adjunct in the laboratory diagnosis of PT, particularly when repeated bacteriological investigations for M. tuberculosis in clinical specimens are negative. Levels of ICs tend to decrease with the duration of anti-tuberculosis chemotherapy and their detection can also be used to assess the clinical response to therapy in patients with PT.

Antibodies, Bacterial↗

PubMed1992

Evaluation of purified protein derivative in the laboratory diagnosis of tuberculous meningitis.

An enzyme-linked immunosorbent assay (ELISA) was standardised for the quantitation of IgG antibody in cerebrospinal fluid (CSF) specimens of patients with tuberculous meningitis (TBM). Purified protein derivative (PPD1) from H37Ra M tuberculosis was used as the antigen in the assay. The sensitivity of the ELISA with this antigen was evaluated in the CSF of 10 culture positive and 40 culture negative patients with TBM. The specificity of the assay was evaluated in the CSF of 50 patients with non-tuberculous neurological diseases (control group). The results obtained with this antigen were compared with commercially available tuberculin purified protein derivative (PPD2) and BCG antigens. PPD2 gave false negative results (50%) in culture positive patients with TBM, and BCG antigen gave false positive results in 32% of non-tuberculous subjects. PPD1 gave a sensitivity of 60% in culture negative patients with TBM and no false positive reactions in the non-tuberculous group. PPD1 antigen, in contrast to other mycobacterial antigens, can be very easily prepared in any routine laboratory, and this antigen is recommended for use as an aid in the laboratory diagnosis of TBM, particularly in culture negative patients with TBM.

Antibodies, Bacterial↗

PubMed1991

Enzyme-linked immunosorbent assay to detect Mycobacterium tuberculosis antigen 5 and antimycobacterial antibody in cerebrospinal fluid of patients with tuberculous meningitis.

Inhibition ELISA and indirect ELISA was standardised to detect Mycobacterium tuberculosis antigen 5 and antimycobacterial antibody in cerebrospinal fluid (CSF) specimens of 75 patients with tuberculous meningitis, (TBM) and 75 patients with non-tuberculous neurological diseases (control group). In both ELISAs, no false-negative results were observed in 15 culture proven patients with TBM. Detection of M. tuberculosis antigen 5 is more sensitive than detection of antimycobacterial antibody. However, both ELISAs showed 100% specificity for tuberculous aetiology in culture-negative patients with TBM. ELISA should be considered as one of the approaches in the laboratory diagnosis of TBM, particularly when standard bacteriological methods are unable to demonstrate M. tuberculosis in CSF specimens of patients with TBM.

Adolescent↗

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↗