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Biomedical subjects

J Muliyil

Publications and source records attributed to J Muliyil.

At least 19 recordsLinked to original sources

Active epilepsy as an index of burden of neurocysticercosis in Vellore district, India.

OBJECTIVE: To determine the contribution of neurocysticercosis (NCC) to the causation of active epilepsy (AE) in a south Indian community. METHODS: We conducted a door-to-door survey of 50,617 people between the ages of 2 and 60 years in a rural (38,105 people) and urban setting (12,512 people) in the Vellore district of the south Indian state of Tamil Nadu to identify patients with AE. Patients with AE were investigated with a contrast-enhanced CT scan and serologic study using enzyme-linked immunotransfer blot (EITB) for cysticercal antibodies. RESULTS: We identified 194 patients with AE. The prevalence of AE was 3.83 per 1,000 people, with the prevalence in the urban clusters more than twice that in the rural clusters (6.23 vs 3.04 per 1,000) (p < 0.0001). A diagnosis of NCC was made in 46 (28.4%) of the 162 patients undergoing a CT scan, and EITB was positive in 21 (13%) patients. Overall, 55 (34%) patients were diagnosed with NCC (11 definitive NCC and 44 probable NCC). There was no significant difference in the prevalence of NCC causing AE in the urban (1.28 per 1,000) and rural (1.02 per 1,000) communities. CONCLUSIONS: NCC is the cause of nearly one-third of all cases of AE in both the urban and rural regions. Extrapolating our results to the country as a whole leads to an estimated disease burden of 1 million patients in India with AE attributable to NCC.

Adolescent↗

Solar disinfection of water for diarrhoeal prevention in southern India.

AIMS: To evaluate the efficacy and acceptability of solar irradiation in the prevention of diarrhoeal morbidity in children under 5 years of age, in an urban slum in Vellore, Tamil Nadu. METHODS: A total of 100 children were assigned to receive drinking water that had been subjected to solar disinfection in polyethylene terephthalate bottles. One hundred age and sex matched controls were also selected. Both groups were followed by weekly home visits for a period of six months for any diarrhoeal morbidity. At the end of the follow up period, the acceptability of the intervention was assessed by interviews, questionnaires, and focus group discussions. RESULTS: There was significant reduction in the incidence, duration, and severity of diarrhoea in children receiving solar disinfected water, despite 86% of the children drinking water other than that treated by the intervention. The incidence of diarrhoea in the intervention group was 1.7 per child-year, and among controls 2.7 per child-year, with an incidence rate ratio of 0.64 (95% CI -0.48 to 0.86). The risk of diarrhoea was reduced by 40% by using solar disinfection. In qualitative evaluation of acceptability, most women felt that solar disinfection was a feasible and sustainable method of disinfecting water. CONCLUSIONS: Solar disinfection of water is an inexpensive, effective, and acceptable method of increasing water safety in a resource limited environment, and can significantly decrease diarrhoeal morbidity in children.

Child, Preschool↗

Prevalence of HIV infection in psychiatric patients attending a general hospital in Tamil Nadu, south India.

An anonymous, unlinked study was conducted to detect antibodies to HIV-1 or HIV-2 infections in 1,160 consecutive, newly registered, adult psychiatric outpatients at a general hospital in South India to determine whether psychiatric patients presenting to general hospitals are a population at high risk for HIV infection and should be routinely screened. The seroprevalence of HIV infection (12/1160; 1.03%; 95% CI = 0.4-1.6%) did not approximate rates expected of a high-risk group compared to the national (0.7%) or regional community (1.8%) prevalence. It did not differ significantly from HIV seroprevalence in non-psychiatric patients (233/35450; 0.7%; 95% CI = 0.57-0.74%) who were systematically screened (relative risk = 1.57; 95% CI = 0.88-2.80) during the same period, but was greater than the seroprevalence in healthy blood donors (0.5%; p = 0.02; relative risk = 2.15 95% CI = 1.17-3.95). Non-psychiatric patients were also more likely to be HIV infected than blood donors (p = 0.02; relative risk = 1.37; 95% CI = 1.05-1.78). These findings have implications for HIV testing policies among psychiatric and non-psychiatric patients presenting to general hospitals in India.

Adolescent↗

Optic disc morphology in south India: the Vellore Eye Study.

AIM: To evaluate the morphology of the optic nerve head in an unselected population group in south India. METHODS: The study included 70 subjects forming a population based sample, selected in a random manner. Mean age was 47.5 (SD 8.7) years, mean refractive error measured -0.07 (1.11) dioptres (range -4.50 to +2.50 dioptres). Optic disc slides were morphometrically analysed. RESULTS: Mean optic disc area measured 2.58 (0.65) mm(2). It was statistically independent of age and refractive error. Optic disc shape was slightly vertically oval. Mean neuroretinal rim area was 1.60 (0.37) mm(2). It was significantly and positively correlated with optic disc size and optic cup size. It was independent of age, sex, refractive error, and axial length. In all subjects included in the study, the rim was smallest in the temporal horizontal optic disc sector. Mean horizontal cup/disc diameter ratio (0.66 (0.07)) was significantly (p<0.001) higher than the mean vertical cup/disc diameter ratio (0.56 (0.08)). Both ratios were highly significantly (p <0.001) and positively correlated with optic disc size. The alpha zone of parapapillary atrophy (0.84 (0.29) mm(2)), and beta zone (0.13 (0.38) mm(2)), respectively, occurred in 69 (98.6%) subjects and in eight (11.4%) subjects, respectively. They were significantly larger in the temporal horizontal sector. The alpha zone was significantly (p<0.001) larger and occurred significantly more often than beta zone. Retinal arterioles and venules were wider, and in spatial correlation, the visibility of the retinal nerve fibre layer was significantly better, in the temporal inferior disc arcade and the temporal superior arcade than in the nasal superior arcade and the nasal inferior vessel arcade. Except for the absolute size measurements these optic nerve head parameters did not differ markedly (p >0.05) from the values found in white people. CONCLUSIONS: South Indians and white people do not show marked differences in the morphology of the optic nerve head as measured by morphometric optic disc parameters, with the possible exception of the absolute optic disc dimensions.

Adult↗

Five year risk of progression of primary angle closure suspects to primary angle closure: a population based study.

AIM: To report progression of primary angle closure suspects (PACS) to primary angle closure (PAC) at the 5 year follow up of a population based sample. METHODS: 82 of 118 PACS who could be contacted and 110 randomly selected normals from a population based survey in 1995 were invited for a follow up examination in 2000. Progression to PAC was based on the development of raised IOP or synechiae in a PACS. RESULTS: 50 of the 82 PACS contacted were examined. 11 (22%; 95% CI 9.8 to 34.2) developed PAC (seven synechial and four appositional); all were bilateral PACS. Two of 50 people previously diagnosed as PACS were reclassified as normal. One person among the 110 normals progressed to PAC. The relative risk of progression among PACS was 24 (95% CI 3.2 to 182.4). There was no significant difference in axial length, anterior chamber depth, or lens thickness between those who progressed and those who did not. None of the patients developed optic disc or field damage attributable to angle closure. One angle closure suspect was diagnosed to have normotensive glaucoma. CONCLUSION: In this population based study of PACS the 5 year incidence of PAC was 22%; none developed functional damage. Bilateral PACS was a clinical risk factor for progression.

Adult↗

Knowledge of epidemiology and statistics for an ophthalmic practitioner.

Ophthalmologists are frequently confronted with treatment options that claim to be better than those currently in use. Statistically significant P values are invariably provided by way of proof. For many ophthalmologists a simple look at this revered P value is enough evidence that a statistically significant result has indeed been obtained. Unfortunately, traditional interpretation of a study based on the P value at an arbitrary cut-off (P<0.05 or any other value) limits the ability to fully appreciate clinical implications. In this article the authors introduce the reader to and illustrate the use of "confidence intervals" as opposed to P values in examining the applicability of study results. Further, what is statistically significant may not necessarily be clinically significant; perhaps not enough for the practitioner to change from the currently preferred method of treatment. To resolve this, the authors have also used common ophthalmic examples to introduce the "number needed to treat", as a simple clinical approach for the practising ophthalmologist wishing to assess the clinical significance of treatment options.

Clinical Trials as Topic↗

Use of pattern standard deviation instead of corrected pattern standard deviation in Anderson's criteria.

PURPOSE: To determine whether the use of pattern standard deviation instead of corrected pattern standard deviation, as part of Anderson's criteria, makes a difference in categorizing a single field printout using the full threshold strategy on the Humphrey's Field Analyzer. MATERIALS AND METHODS: Forty-eight patients with glaucomatous field defects of varying severity underwent full threshold perimetry on the Humphrey's Field Analyzer. The third field of one eye was used for the study. The agreement between CPSD and PSD alone was determined. Each field was then categorized using Anderson's criteria first using CPSD and then PSD. The kappa statistic was used to determine agreement in both situations. RESULTS: The agreement between CPSD and PSD alone, as determined by kappa, was 0.77. The kappa statistic for categorization using Anderson's criteria was 0.82; the weighted kappa was 0.92. CONCLUSION: There was almost perfect agreement using the PSD instead of CPSD as part of Anderson's criteria. This substitution seems valid for the spectrum of field defects used in this series, at least for the full threshold programs.

Adult↗

The role of central corneal thickness in the diagnosis of glaucoma.

PURPOSE: To determine the effect of central corneal thickness (CCT) on applanation tonometry and any resultant misclassification of normals as ocular hypertension. METHOD: The central corneal thickness was measured using the ultrasound pachometer in 50 normals, 25 glaucoma and 23 ocular hypertensive patients. The student's "t" test was used to determine any significant difference in CCT between the three groups. RESULTS: There was a statistically significant difference in the mean CCT of the ocular hypertensives (0.574 +/- 0.033 mm) as compared to the glaucomas (0.534 +/- 0.030 mm) and normals (0.537 +/- 0.034 mm). Applying the described correction factor for corneal thickness, 39% of eyes with ocular hypertension were found to have a corrected IOP of 21 mmHg or less. CONCLUSIONS: Increased corneal thickness in ocular hypertension may lead to an overestimation of IOP in 39% of cases. Measurement of central corneal thickness is advisable when the clinical findings do not correlate with the applanation IOP.

Adult↗

Comparison of optical and ultrasound pachometry.

PURPOSE: (1) To determine the agreement between optical and ultrasound pachometry for central corneal thickness measurements used to "correct" applanation intraocular pressure (IOP) readings. (2) To determine the inter- and intra-observer variability of optical and ultrasound pachometry. METHOD: Central corneal thickness (CCT) was measured in a masked manner using optical and ultrasound pachometry in 50 normal eyes. To assess intra- and inter-observer variability, multiple masked measurements were obtained in 51 eyes (optical pachometry) and 34 eyes (ultrasound pachometry). Agreement was determined by a published technique that uses the mean of the differences, standard error (SE) and standard deviation (SD). RESULTS: The mean difference in CCT between optical and ultrasound pachometry was 0.001 mm (SD 0.031 mm; SE 0.00439 mm). The mean inter-observer difference for the optical pachometer was 0.019 mm (SD 0.049 mm; SE 0.0069); the mean intra-observer difference was 0.003 mm (SD 0.017; SE 0.0.0024). The mean inter-observer difference for ultrasound pachometry was 0.001 mm (SD 0.009; SE 0.0015) and the mean intra-observer difference was 0.002 mm (SD 0.011; SE 0.0019). CONCLUSIONS: Ultrasound pachometry is the more reliable method for the measurement of central corneal thickness used to correct applanation IOP values. Optical pachometry had good intra-observer variability. The range of error in IOP correction for corneal thickness (inter-observer) that can occur using the ultrasound pachometer is -1.2 mmHg to +1.4 mmHg as compared to -5.6 mmHg to +8.5 mmHg with the optical pachometer.

Cornea↗

An introduction to clinical decision analysis in ophthalmology.

Ophthalmologists are often confronted with difficult clinical management problems. In such cases, even published experience may be limited; consequently multiple, generally unproven management options are usually available. When placed in such situations, most of us decide on the most appropriate course of action based on intuition or (limited) previous experience. In this article, we use examples to introduce the concept of decision analysis, a method of generating objective decisions for complex clinical problems.

Decision Support Techniques↗

Measles vaccination before nine months.

OBJECTIVE: To measure the protective effect of measles vaccine administered before 9 months of age and compare overall mortality of children vaccinated at 6-8 months and at 9-11 months. METHOD: Non-concurrent cohort study involving all 13 134 children born between 16 January 1986 and 31st December 1991 in Kaniyambadi block near Vellore who had not left the area by six months of age. Main outcome measures were risk of disease and death among the under-five-year-olds according to age at measles immunization. RESULTS: Unimmunized children had a higher risk of developing measles compared to the immunized (P < 0.05). There was no significant difference in risk of measles among those vaccinated prior to and after nine months of age. Unvaccinated children were at significantly higher risk of death than vaccinated children (P < 0.001). There was no difference in risk of death between infants vaccinated between 6 and 8 months and those vaccinated between 9 and 11 months. There was no difference in the risk of death between boys and girls vaccinated between 6 and 8 months with standard-titre Edmonston-Zagreb vaccine. CONCLUSION: Administration of standard-titre Edmonston-Zagreb measles vaccine at 6-8 months is an effective and safe preventive measure for measles, especially where the age-specific attack rate for children < 9 months is high.

Age Distribution↗

Incidence of disabilities among multi-bacillary cases after initiation of multidrug therapy and factors associated with the risk of developing disabilities.

Out of the 1724 new cases registered between 1985 to 1992, 1169 could be contacted. The overall incidence of disabilities was 6.8%. Age above 45 years, bacteriopositivity and thickening of three or more trunk nerves were associated with a higher risk of disabilities. Staff training, patient education and steroid availability in the field were the suggested methods of reducing the occurrence of disabilities in leprosy patients.

Adult↗

Prevalence of primary glaucoma in an urban south Indian population.

Glaucoma is fast emerging as a major cause of blindness in India. In order to estimate the prevalence of primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) in an urban South Indian population, we examined 972 individuals aged 30-60 years, chosen using a cluster sampling technique from 12 census blocks of Vellore town. They underwent a complete ocular examination, including applanation tonometry and gonioscopy, at the Medical College Hospital. Characteristic field defects on automated perimetry was a diagnostic requisite for POAG. Prevalence (95% CI) of POAG, PACG, and ocular hypertension were 4.1 (0.08-8.1), 43.2 (30.14-56.3), and 30.8 (19.8-41.9) per 1,000, respectively. All the PACG cases detected were of the chronic type. Hitherto unavailable community-based information on primary glaucoma in our study population indicates that PACG is about five times as common as POAG.

Adult↗

An epidemic of diarrhoea in south India caused by enteroaggregative Escherichia coli.

A diarrhoeal epidemic in a village close to Vellore was investigated in January 1996. Faecal samples were obtained from 20 subjects with diarrhoea and from 11 individuals without diarrhoea (controls) and were examined for bacterial, viral and parasitic enteropathogens. Water samples from all sources in the village were analysed. The epidemic affected all age groups (overall attack rate 15%). The mean duration of diarrhoea was 11 days. Individuals who consumed water exclusively from a borewell had a lower relative risk (RR) of disease (0.14, 95% Cl 0.02-1.01) compared to users of two open wells (RR 6.93, Cl 0.99-48.66 and RR 7.81, Cl 1.02-59.79, respectively). No conventional bacterial enteropathogens were isolated from the stool samples. Enteroaggregative Escherichia coli (EAggEC) were identified in the stool of 11 of 20 subjects with diarrhoea, and in 1 of 11 control samples (P = 0.02). All the EAggEC isolates from the patients had identical antibiotic sensitivity patterns and produced a toxin in Ussing chamber studies. Serotyping indicated that all the EAggEC from individuals with diarrhoea belonged to one or other of two serotypes. All water samples had high coliform counts and E. coli were cultured from the two open wells but not from the borewell. The evidence suggests that EAggEC was responsible for this outbreak of diarrhoea. EAggEC should be considered as a possible pathogen in unexplained diarrhoeal outbreaks in developing countries.

Adolescent↗