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Biomedical subjects

A Mathai

Publications and source records attributed to A Mathai.

At least 19 recordsLinked to original sources
PubMed2004

Serum tumour necrosis factor-alpha and soluble tumour necrosis factor receptors levels in patients with Guillain-Barre syndrome.

OBJECTIVES: To estimate the serum concentrations of Tumour Necrosis Factor alpha (TNF-alpha) and soluble TNF receptors (s TNF-RI and TNF-RII) in patients with Guillain-Barre syndrome (GBS), before and after treatment. MATERIAL AND METHODS: The serum TNF-alpha and the soluble TNF receptors concentrations were measured by a sandwich enzyme-linked immunosorbent assay (ELISA) in 47 patients with GBS before and after the treatment - IVI therapy (n=26); Plasma Exchange (n=21). RESULTS: At the time of admission, the serum TNF-alpha concentrations were elevated (32.5-182.5 pg/ml) in 41/47 GBS patients (87.2%). Following the treatment (IVIG or PE), there was a significant decrease in the serum TNF-alpha concentrations (8.5-58.5 pg/ml) in these 41 GBS patients. The soluble TNF receptors, particularly sTNF-RII concentrations were significantly increased in GBS patients treated by IVIG therapy. CONCLUSIONS: The results of this indicated that (a) Elevated serum concentrations of TNF-alpha showed a positive correlation with the disease severity in patients with GBS. (b) The decrease in the serum TNF-alpha and increase in the serum soluble TNF receptors, particularly sTNF-RII showed a positive correlation with the neurological recovery in GBB patients following treatment.

Enzyme-Linked Immunosorbent Assay↗
PubMed2003

Detection of heat stable mycobacterial antigen in cerebrospinal fluid by Dot-Immunobinding assay.

BACKGROUND: Isolation of Mycobacterium tuberculosis in cerebrospinal fluid (CSF) specimen in patients with tuberculous meningitis (TBM) is infrequent and carries low sensitivity. Thus development of an alternative laboratory diagnostic test is essential for the early diagnosis and treatment of TBM. OBJECTIVE: A simple, rapid Dot immunobinding assay (Dot-Iba), for the laboratory diagnosis of TBM is devised. This method minimizes the risk of handling infectious material in the laboratory. METHOD: The Dot-Iba was standardized with heat-inactivated M tuberculosis antigen (PPD). The heat-inactivated CSF from TBM and non-TBM patients was similarly assayed and it can detect antigen upto 1ng/ml in CSF. RESULT: A positive result was obtained in all the five culture positive patients with TBM and in 20/25 probable TBM. A negative result was obtained in 38/40 CSF from disease control group. The overall sensitivity and specificity of Dot-Iba was 83.3% and 95% respectively. CONCLUSION: Dot-Iba can be used as an adjunct for the laboratory diagnosis of TBM, particularly in culture negative TBM patients and also in those clinical situations where no laboratory tests are available to distinguish between TBM and partially treated pyogenic meningitis.

Antigens, Bacterial↗
PubMed2003

Circulating tumour necrosis factor alpha & soluble TNF receptors in patients with Guillain-Barre syndrome.

BACKGROUND & OBJECTIVES: Tumour necrosis factor-alpha (TNF-alpha) is regarded as one of the immune factors that can induce demyelination of peripheral nerves in patients with Guillian-Barre syndrome (GBS). This present study was undertaken to find out the role of TNF-alpha and soluble TNF receptors in the pathogenesis of GBS; and to study the effect of intravenous immunoglobulin (ivIg) therapy on the serum TNF-alpha and soluble TNF receptors in patients with GBS. METHODS: Thirty six patients with GBS in progressive stages of motor weakness were included in this study. The serum TNF-alpha and soluble TNF receptors (TNF-RI, TNF-RII) were measured in the serum samples of these patients before and after ivIg therapy by a sandwich ELISA. RESULTS: Of the 36 patients with GBS, 26 (72.2%) showed elevated serum TNF-alpha levels prior to ivIg therapy. Following a complete course of ivIg therapy there was a progressive decrease in the serum TNF-alpha concentrations in these 26 patients. On the other hand, the soluble TNF receptors, particularly TNF-RII showed an increase in the serum of GBS patients following ivIg therapy. INTERPRETATION & CONCLUSION: The results indicate that ivIg reduces the serum TNF-alpha concentrations in the GBS patients having elevated levels prior to ivIg therapy. Elevated serum levels of soluble TNF receptors following ivIg therapy may play a protective role by inhibiting the demyelinating effect of TNF-alpha in the peripheral nerves of patients with GBS.

Adolescent↗
PubMed2003

Intravenous immunoglobulin reduces serum tumor necrosis factor alpha in patients with Guillain-Barre syndrome.

BACKGROUND: Tumor necrosis factor a TNF-alpha has a possible role in the pathogenesis of the Guillain-Barre syndrome (GBS). AIMS: To study the effect of intravenous immunoglobulin (IVIg) on serum TNF-alpha concentrations in patients with GBS. MATERIAL AND METHODS: The effect of IVIg on TNF-alpha was evaluated in 36 patients with GBS. Serum TNF-alpha concentration was measured by enzyme-linked immunosorbent assay (ELISA). The sera of 22 (61%) patients with GBS showed elevated concentrations of TNF-alpha (35-182 pg/ml) and these sera were individually incubated in vitro with IVIg (0.25 mg/ml) at 37 degrees C for 24 hours. RESULTS: The serum TNF-alpha concentrations in the 22 GBS patients with elevated levels showed a steady decline (60.34-19.78 pg/ml) following incubation with IVIg. These 22 patients also received IVIg therapy, and serum TNF-alpha concentrations showed a significant decline (65.5-9.75 pg/ml) at the end of the therapy. At the time of discharge from the hospital, there was a positive correlation between neurological recovery and decline in TNF-alpha concentrations in these 22 GBS patients. CONCLUSIONS: The results of this study indicate that elevated levels of TNF-alpha occur in a proportion of patients with GBS and in these patients elevated serum TNF-alpha levels decline with IVIg therapy.

Guillain-Barre Syndrome↗
PubMed2002

A comparative evaluation of dot immunobinding assay (Dot-Iba) and polymerase chain reaction (PCR) for the laboratory diagnosis of tuberculous meningitis.

The results of a Dot immunobinding assay (Dot Iba) for the detection of mycobacterial antigen in the cerebrospinal fluid (CSF) of 45 patients with tuberculous meningitis (TBM) were compared with the results of a polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis. In eight patients with culture proven TBM, Dot-Iba gave positive results, while PCR yielded positive results only in six patients. The overall sensitivities of Dot-Iba and PCR in 37 patients with culture negative (probable) TBM were 75.67% and 40.5% respectively. Dot-Iba, in contrast to PCR is a rapid and relatively easier method. More importantly, Dot-Iba is suitable for the routine application for the laboratory diagnosis of TBM and therefore best suited to laboratories in the developing world.

Antigens, Bacterial↗
PubMed2002

Immunocytochemical method for early laboratory diagnosis of tuberculous meningitis.

A simple immunocytochemical method was standardized for the direct demonstration of mycobacterial antigen in cerebrospinal fluid (CSF) specimens of patients with tuberculous meningitis (TBM). CSF-cytospin smears were prepared from 22 patients with a clinical diagnosis of TBM and also from an equal number of patients with nontuberculous neurological diseases (disease control). Immunocytological demonstration of mycobacterial antigens in the cytoplasm of monocytoid cells was attempted, by using rabbit immunoglobulin G to Mycobacterium tuberculosis as the primary antibody. Of the 22 CSF-cytospin smears from TBM patients, 16 showed positive immunostaining, while all of the CSF-cytospin smears from the disease control showed negative immunostaining for mycobacterial antigen. The technical aspects of this immunocytological method for the demonstration of mycobacterial antigens are simple, rapid, and reproducible, as well as specific, and therefore can be applied for the early diagnosis of TBM, particularly in patients in whom bacteriological methods did not demonstrate the presence of M. tuberculosis in the CSF.

Antigens, Bacterial↗
PubMed2001

A newer approach for the laboratory diagnosis of tuberculous meningitis.

In this prospective study, a simple method was standardized for measuring circulating mycobacterial antigen in the cerebrospinal fluid (CSF) for the laboratory diagnosis of tuberculous meningitis (TBM). The heat-inactivated CSF specimens from tuberculous and non-tuberculous patients were subjected to sodium dodecyl sulfate (SDS) - polyacrylamide gel electrophoresis (PAGE) (SDS-PAGE) and they were subsequently transferred onto nitrocellulose membrane (NCM) Using a rabbit polyvalent antibody to M tuberculosis, a heat stable 82 kDa mycobacterial antigen was demonstrated in the CSFs of patients with TBM. This antigen was conspicuous by its absence in the CSFs of non-tuberculous subjects. Due to inactivation of CSF specimens, there is a minimal risk of handling of infectious material in the laboratory. Besides, this newer approach is simple, inexpensive and can be readily applied in any routine clinical laboratory and it is particularly suited to developing countries.

Animals↗
PubMed2001

Significance of serum antibody to GD1b ganglioside in patients with Guillain-Barré syndrome.

BACKGROUND & OBJECTIVES: The precise etiological factors in Guillain-Barré syndrome (GBS) are still unknown. However, humoral and cellular immune factors may have a role in the pathogenesis of GBS. The present study was undertaken to evaluate the clinical significance of circulating serum IgG antibody to GD1b ganglioside in patients with GBS. METHODS: Serial samples of serum were collected from 18 patients with GBS undergoing plasma exchange (PE) during their hospital stay. Serum IgG antibody titers to GD1b, before, during as well as following PE were measured by an indirect enzyme-linked immunosorbent assay (ELISA). RESULTS: In 10 of 18 patients with GBS the antibody to GD1b was present in high titers (1:640-1:5120) prior to PE and the antibody titers in these 10 patients decreased following PE. At the time of completion of the study, the anti GD1b antibody titers declined in relation to clinical recovery in 7 of 10 patients with GBS. INTERPRETATION & CONCLUSION: The findings of the present study show that antibody to GD1b gangliosides may be one of the immunological factors in the pathogenesis of GBS and PE decreases the anti GD1b antibody titers in these patients.

Antibodies↗
PubMed2001

A dot-immunobinding assay (dot-Iba) for rapid diagnosis of pulmonary tuberculosis.

IgG antibody to Mycobacterium tuberculosis from the sera of patients with 'definite' pulmonary tuberculosis (PT) was isolated and coupled with Cyanogen bromide-Sepharose 4B. Using an immunoabsorbent affinity chromatography, 14 kDa antigen was recovered from the culture filtrates of M. tuberculosis. With this mycobacterial antigen, a dot immunobinding assay (Dot-Iba) was developed for the detection of specific antibody to M. tuberculosis in the sera of patients with PT and controls. The assay gave positive results in all the 12 sputum-smear positive [acid fast bacilli (AFB)] patients with PT and gave negative results in the 50 sera from control groups. The Dot-Iba as described in this study, is simple, rapid and specific for laboratory diagnosis of PT.

Adolescent↗
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↗