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Biomedical subjects

A Mathai

Publications and source records attributed to A Mathai.

At least 19 recordsLinked to original sources
PubMed2000

Significance of circulating immune complexes in myasthenia gravis.

In this study, circulating immune complexes (CICs) were isolated and characterized in the sera of myasthenia gravis (MG) patients with thymoma and MG patients without any thymic lesions. High titres of antistriational antibodies in the CICs were demonstrated by an indirect immunofluorescence (IF) method in 60 per cent (15/25) MG patients with thymoma. The CICs showed a steady decrease in these 15 patients during the post thymectomy period. Antistriational antibodies in the CICs of MG patients without thymic lesions were not detected by IF method. The results of this study emphasised the usefulness of estimation of CICs in the overall management of MG patients with thymoma.

Antigen-Antibody Complex↗
PubMed1999

Rapid diagnosis of tuberculous meningitis by a dot immunobinding assay To detect mycobacterial antigen in cerebrospinal fluid specimens.

In the present prospective study, a dot immunobinding assay (Dot-Iba) was standardized to measure the circulating mycobacterial antigen in cerebrospinal fluid (CSF) specimens for the laboratory diagnosis of tuberculous meningitis (TBM). Immunoglobulin G antibody specific for Mycobacterium tuberculosis in a CSF specimen from a patient with culture-proven TBM was isolated and was coupled with activated cyanogen bromide-Sepharose 4B. By immunosorbent affinity chromatography, a 14-kDa antigen was isolated from the culture filtrate of M. tuberculosis. Antibody to the 14-kDa mycobacterial antigen was raised in rabbits. The Dot-Iba in this study gave no false-positive results with CSF specimens from patients with nontuberculous neurological diseases. The assay gave positive results for all five patients with culture-proven TBM. The Dot-Iba described in the present report is simple, rapid, sensitive, specific, and, more importantly, suitable for routine application in laboratories in developing countries.

Animals↗
PubMed1999

Incidence and management of posteriorly dislocated nuclear fragments following phacoemulsification.

PURPOSE: To report the incidence, management and complications of nucleus dislocation into the vitreous during phacoemulsification. METHODS: Retrospective review of 1250 consecutive phacoemulsification performed by consultants and residents in a teaching hospital. RESULTS: The incidence of nucleus drops was 0.8% (10 out of 1250). Loss of nuclear fragments occurred during phacoemulsification in 9 patients. In one, the dislocation was caused by hydro-dissection. All except one patient (who refused further intervention) underwent pars plana vitrectomy with removal of nuclear fragments. Eight of them had intraocular lens (IOL) inserted at the time of cataract surgery or at vitrectomy; one patient was scheduled for a secondary IOL. Postoperative best corrected visual acuity ranged from 6/24-6/6; 8 patients achieved a vision of 6/12 or better. Complications included cystoid macular oedema (5 patients), retinal break (1 patient) and retinal detachment (1 patient). CONCLUSION: Appropriate management of posteriorly dislocated nucleus can restore good visual acuity. The use of phacoemulsification mandates availability of referral facilities for management of complications.

Humans↗
PubMed1997

VISTECH contrast sensitivity testing in primary open angle glaucoma.

Contrast sensitivity has been recommended as a screening and diagnostic test in primary open angle glaucoma (POAG). We tested contrast sensitivity (CS) using Vistech charts in 184 eyes of 95 patients. Three groups were examined--established primary open angle glaucoma, glaucoma suspects and age matched controls. The distribution of contrast sensitivities amongst the three groups were similar. The median contrast sensitivity of glaucoma suspects and controls were well within normal limits while that of the POAG group fell along the lower limit of normal. In all three groups the younger subjects scored better than the older, indicating a depression of contrast sensitivity with increasing age. Even if depression of any one spatial frequency was considered abnormal, the test yielded a sensitivity of 55.4% and specificity of 69.5%. Similarly contrast sensitivity testing was found to be of little use in detecting field defects a maximum sensitivity of 47.3% and specificity of 73.3%. Vistech contrast sensitivity testing is not a useful test in POAG screening or diagnosis.

Adult↗
PubMed1995

Characterization of mycobacterial antigens by Elisa and immunoblot methods.

Antibodies to two mycobacterial antigens viz - culture filtrate antigen (CFA) and Mycobacterium tuberculosis antigen 5 were raised in rabbits. Enzyme-linked immuno sorbent assay (ELISA) and immunoblot methods were used for the evaluation of the specificity of the rabbit antibodies to M. tuberculosis. Immunoblot method is more sensitive than ELISA for the detection of antibodies to M. tuberculosis in the rabbit sera. It is being emphasised that characterisation of the mycobacterial antigens and evaluation of the specificity of the antimycobacterial antibodies are essential prior to their applications as an adjunct in the laboratory diagnosis of human mycobacterial disease.

Animals↗
PubMed1994

Diagnosis of tuberculous meningitis confirmed by means of an immunoblot method.

In order to define the mycobacterial antigens that may be specifically associated with human tuberculous infection, the cerebrospinal fluid (CSF) specimens of 30 patients with tuberculous meningitis (TBM) and of an equal number of patients with non-tuberculous meningitis (controls) were compared by means of an immunoblot method for detecting antibody to Mycobacterium tuberculosis. In the CSF of controls, mycobacterial antibody was either absent or, when present, was found to react with 27, 30 and 45 KDa antigens of M. tuberculosis. Among patients with TBM, the numbers as well as intensities of the immunostained bands in the nitrocellulose membranes (NCM) were greater than among controls. Furthermore, a unique disease-associated mycobacterial antigen, 35 KDa of M. tuberculosis, was found to react with a specific antibody in the CSF of patients with TBM but was not detected in the CSF of any of the controls. This 35 KDa antigen could be easily identified in the NCM. The immunoblot method showed 100% sensitivity in all the culture-positive patients with TBM. Because of the high degree of specificity as well as sensitivity of the immunoblot method, we consider that this method is of value for confirming the diagnosis of TBM.

Antibodies, Bacterial↗
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↗