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Biomedical subjects

G T John

Publications and source records attributed to G T John.

At least 37 records · Page 2Linked to original sources
PubMed1994

Nondiabetic renal disease in noninsulin-dependent diabetics in a south Indian Hospital.

Eighty patients with non-insulin-dependent diabetes mellitus being treated in a south Indian hospital were biopsied to confirm suspected nondiabetic renal disease (NDRD). The positive predictive value of the standard clinical indicators for NDRD in the presence or absence of diabetic retinopathy was 54 and 87%, respectively. These values are higher than those given by comparable studies in Western populations. This is probably due to a higher prevalence of NDRD in the population of south India, and especially of proliferative glomerulonephritis, which was found in 21.5% of the patients studied. Standard clinical predictors of NDRD in diabetics have a high predictive value in the tropics where there is a high prevalence of proliferative glomerulonephritis.

Adult↗
PubMed1994

Free radical injury in human renal allograft rejection.

Plasma and renal tissue levels of lipid peroxide and plasma vitamin E were estimated as measures of free radical injury in five renal allograft recipients with untreated and four with unsuccessfully treated acute cellular rejection and compared with 11 control patients with minimal change disease. Plasma lipid peroxide was significantly higher in patients studied before antirejection therapy (13.2 +/- 3.5 nmol/ml; P < 0.01) as well as in those after unsuccessful antirejection treatment (11.7 +/- 0.7 nmol/ml; P < 0.01), compared to controls (5.7 +/- 2.8 nmol/ml). Levels of plasma vitamin E and renal tissue lipid peroxide were similar in both groups, however the latter was significantly raised in patients evaluated prior to antirejection therapy than in those after unsuccessful antirejection therapy (5.1 +/- 1.7 and 3.0 +/- 0.8 nmol/mg protein; P < 0.05). These findings suggest possible free radical mediated injury during renal allograft rejection.

Adolescent↗
PubMedDate not supplied

The effect of cyclosporin A on plasma lipids during the first year after renal transplantation.

BACKGROUND: The serum lipid profile of renal transplant recipients from the Indian subcontinent is not available. Cyclosporin A causes dyslipidaemia, a major risk factor for coronary artery disease which is a significant cause of mortality in these patients. We compared the effect of two dosage schedules of cyclosporin A on the lipid profile of transplant recipients. METHODS: Two hundred and eight renal allograft recipients were randomized to receive either a high or a low dose of cyclosporin A for 12 months. Their cholesterol and triglyceride levels were measured at monthly intervals for the first six months and at the ninth and twelfth months. The area under the curve was measured and multiple linear regression analysis was done. ANOVA for repeated measures was carried out. RESULT: Patients receiving a higher dose of cyclosporin A had higher cholesterol and triglyceride levels compared to those receiving the lower dose schedule. The multivariate analysis showed that a low dose of cyclosporin A was significantly associated with reduced cholesterol (p < 0.07) and triglyceride levels (p < 0.04) after controlling the effect of other covariates. ANOVA for repeated measures showed that cholesterol levels were significantly lower in the low-dose cyclosporin A group (p < 0.05). CONCLUSION: Low dose cyclosporin A reduces the risk of dyslipidaemia in Indian renal transplant recipients.

Adult↗
PubMedDate not supplied

Pre-transplant risk factors for renal allograft dysfunction at one year in Indian patients.

BACKGROUND: Only a few patients with end-stage renal disease in the Indian subcontinent receive optimal treatment. Of these only a minority can afford a second renal transplant. Awareness of modifiable pre-transplant risk factors that influence allograft function is crucial before embarking on the first transplant. There are no reports from the Asian subcontinent describing the pre-transplant risk factors. METHODS: We studied the effect of donor age, gender, and relation with the recipient, patient age, gender, HLA matching, native kidney disease and immunosuppression on one-year allograft function using data from 1177 consecutive primary living related donor renal transplants at the Christian Medical College Hospital, Vellore. We performed a univariate followed by a multivariate analysis using a logistic regression model to calculate the odds ratio for the effect of the above factors on two levels of graft function (serum creatinine > 1.4 mg/dl and > 2 mg/dl) at one year. RESULTS: On univariate analysis, older donors, women donors, mother being the donor, men recipients, < 1 HLA antigen match, cyclosporine-based immunosuppression and patient age between 16 and 40 years were associated with serum creatinine levels > 1.4 mg/dl at one year. Multivariate analysis showed that donor-related factors, namely mother as donor, older donors, and a < or = 1 HLA antigen match, were risk factors for graft dysfunction (serum creatinine level > 1.4 mg/dl) at one year. Recipient-related risk factors were male patients and those between the age of 16 and 40 years. CONCLUSION: In patients undergoing living related donor renal transplants from large extended families, a younger haplomatched donor, for instance, a brother, is a better choice than an older haplomatched donor, for instance, the mother, particularly in young male recipients at a higher risk of renal dysfunction.

Adolescent↗
PubMedDate not supplied

Uniform tissues engineered by seeding and culturing cells in 3D scaffolds under perfusion at defined oxygen tensions.

In this work, we assessed whether culture of uniformly seeded chondrocytes under direct perfusion, which supplies the cells with normoxic oxygen levels, can maintain a uniform distribution of viable cells throughout porous scaffolds several milimeters in thickness, and support the development of uniform tissue grafts. An integrated bioreactor system was first developed to streamline the steps of perfusion cell seeding of porous scaffolds and perfusion culture of the cell-seeded scaffolds. Oxygen tensions in perfused constructs were monitored by in-line oxygen sensors incorporated at the construct inlet and outlet. Adult human articular chondrocytes were perfusion-seeded into 4.5 mm thick foam scaffolds at a rate of 1 mm/s. Cell-seeded foams were then either cultured statically in dishes or further cultured under perfusion at a rate of 100 microm/s for 2 weeks. Following perfusion seeding, viable cells were uniformly distributed throughout the foams. Constructs subsequently cultured statically were highly heterogeneous, with cells and matrix concentrated at the construct periphery. In contrast, constructs cultured under perfusion were highly homogeneous, with uniform distributions of cells and matrix. Oxygen tensions of the perfused medium were maintained near normoxic levels (inlet congruent with 20%, outlet > 15%) at all times of culture. We have demonstrated that perfusion culture of cells seeded uniformly within porous scaffolds, at a flow rate maintaining a homogeneous oxygen supply, supports the development of uniform engineering tissue grafts of clinically relevant thicknesses.

Adult↗
PubMedDate not supplied

A six-hour extrapolated sampling strategy for monitoring mycophenolic acid in renal transplant patients in the Indian subcontinent.

BACKGROUND: Therapeutic drug monitoring for mycophenolic acid (MPA) is increasingly being advocated. The present therapeutic range relates to the 12-hour area under the serum concentration time profile (AUC).However, this is a cumbersome, tedious, cost restricting procedure. Is it possible to reduce this sampling period? AIM: To compare the AUC from a reduced sampling strategy with the full 12-hour profile for MPA. SETTINGS AND DESIGN: Clinical Pharmacology Unit of a tertiary care hospital in South India. Retrospective, paired data. MATERIALS AND METHODS: Thirty-four 12-hour profiles from post-renal transplant patients on Cellcept were evaluated. Profiles were grouped according to steroid and immunosuppressant co-medication and the time after transplant. MPA was estimated by high performance liquid chromatography with UV detection. From the 12-hour profiles the AUC up to only six hours was calculated by the trapezoidal rule and a correction factor applied. These two AUCs were then compared. STATISTICAL ANALYSIS: Linear regression, intra-class correlations (ICC) and a two-tailed paired t-test were applied to the data. RESULTS: Comparing the 12-hour AUC with the paired 6-hour extrapolated AUC, the ICC and linear regression(r2) were very good for all three groups. No statistical difference was found by a two-tailed paired t-test. No bias was seen with a Bland Altman plot or by calculation. CONCLUSION: For patients on Cellcept with prednisolone +/- cyclosporine the 6-hour corrected is an accurate measure of the full 12-hour AUC.

Adolescent↗
PubMedDate not supplied

Spectrum of severe chronic kidney disease in India: a clinicopathological study.

BACKGROUND: The healthcare burden due to chronic kidney disease has increased worldwide in the past decade. Elucidating the aetiology of chronic kidney disease may help in identifying strategies for prevention, both in the population and the Individual patient. Only a clinicopathological study can define the exact spectrum of chronic kidney disease since epidemiological studies have not shown a consistent aetiological profile. The histological evidence used to support the diagnosis varies with the degree to which renal biopsy is done. Renal biopsy is the gold standard in making an aetiological diagnosis in renal failure, but as a diagnostic tool in chronic kidney disease it is underutilized. METHODS: This prospective study done at Christian Medical College, Vellore in southern India from 1998 to 2003 aimed to determine the aetiological profile of severe chronic kidney disease by analysing renal biopsies. The value of pre-renal biopsy clinical Judgement in predicting the histological diagnosis was also assessed. Patients with diabetic nephropathy were excluded from the study. RESULTS: Four hundred and fifty-seven patients had evidence of chronic kidney disease as evidenced on biopsy as well as on clinical parameters. Three hundred and twenty-two of these patients (70.5%) had glomerulonephritis as the histological diagnosis. Fifty-five (12%) had Interstitial nephritis, 30 (6.6%) had hypertensive arteriosclerosis and 28 (6.1%) had metabolic nephropathies. The positive predictive value of a pre-biopsy clinical diagnosis in predicting interstitial nephritis was very low (33%). A large number of patients clinically diagnosed to have chronic interstitial nephritis had other aetiologies of chronic kidney disease. CONCLUSION: Glomerulonephritis was the most common cause of chronic kidney disease, not including diabetic nephropathy, followed by interstitial disease and benign arterionephrosclerosis. In patients with unidentified severe chronic kidney disease, renal biopsy provided an aetiological diagnosis.

Adult↗