Non-expression of HLA-C*07:55N is caused by a premature stop codon in exon 3.

Sequencing of HLA-C*07:55N assessed the presence of a premature TAG stop codon at residue 113.

Shell Vial Culture assay for the rapid diagnosis of Japanese encephalitis, West Nile and Dengue-2 viral encephalitis.

BACKGROUND: Encephalitis caused by flaviviruses, Japanese encephalitis virus (JEV) and West Nile virus (WNV) is responsible for significant morbidity and mortality in many endemic countries. Dengue-2 (Den-2) virus is a recent addition to the list of encephalitogenic viruses, after its Central Nervous System (CNS) invasion capability has been established. There is a wide array of laboratory tools that have helped us not only in the diagnosis of these conditions but also in understanding their pathogenesis and pathology. However, there are no reports of Shell Vial Culture (SVC), a centrifuge enhanced tissue culture assay that has revolutionized viral culturing in terms of rapidity and sensitivity being optimized for these flaviviral encephalitic conditions. The present study is an attempt to standardize and evaluate the usefulness of SVC for the laboratory diagnosis of JE, WN and Den-2 encephalitis cases and to compare it with Indirect Immunofluorescence (IIF) technique that detects cell associated virus antigen. Analysis of the various clinical parameters with respect to viral etiology has also been carried out. RESULTS: Pediatric patients constituted the major group involved in the study (92%). Etiological diagnosis of viral encephalitis could be established in twenty nine (58%) patients. JE encephalitis was the commonest with 19 (39%) cases being positive followed by, WN (9 cases-18%) and Den-2 (one case). IIF test could detect antigens of JE, WN and Den-2 viruses in 16(32%), 7(14%) and 1 case respectively. Shell vial culture assay picked up all cases that were positive by IIF test. In addition, SVC assay could detect 3 and 2 more cases of JE and WN encephalitis respectively, that were negative by the IIF test. CONCLUSION: Shell vial culture is a rapid and efficient tool for the etiological diagnosis of JE, WN and Den-2 encephalitis cases. Early, prompt collection, transport and processing of the CSF samples, would make SVC a better method for the rapid diagnosis of these flaviviral infections.

Epidemiological investigation of nosocomial Acinetobacter infections using arbitrarily primed PCR & pulse field gel electrophoresis.

BACKGROUND & OBJECTIVE: Nosocomial infections caused by Acinetobacter spp. are a significant problem worldwide. Information on epidemiological investigation of outbreaks caused by Acinetobacter species in India is lacking. The present investigation was carried out to elucidate molecular epidemiology of Acinetobacter species isolated from nosocomial infections in a tertiary care hospital in south India using two DNA-based typing methods. METHODS: The medical records of 43 patients with Acinetobacter infection during a period of 24 months were reviewed and Acinetobacter isolates obtained from these patients were characterized phenotypically by assimilation tests and genotypically by arbitrarily primed PCR (AP-PCR) and pulse field gel electrophoresis (PFGE). Susceptibility testing results of the Acinetobacter isolates were also analysed. RESULTS: Most of the infections were nosocomial, and the majority of these were acquired in intensive care units (ICUs). A. baumannii accounted for 41.8 per cent (n=18) of all pneumonia acquired in the ICU. AP-PCR with M13 primer distinguished 8 different PCR patterns comprising of 2 to 6 DNA fragments of 0.1 to 1.0 kb. PFGE identified 9 distinct profiles with five subvarients. By APPCR, epidemiologically unrelated strains could not be differentiated and often differences within biotypes of A. baumannii were not detectable. ApaI macrorestriction (PFGE) identified at least 4 outbreaks caused by 3 clones of A. baumannii and one clone of DNA group 13TU, one replacing the other in a well-defined temporal order. INTERPRETATION & CONCLUSION: Most of A. baumannii isolates were multidrug resistant. PFGE was more discriminatory [Discriminatory Index (DI)=0.96 than AP-PCR fingerprinting (DI=0.88)] in the present study. However, AP-PCR fingerprinting is more useful as a simple and rapid identification technique for epidemiological investigation of nosocomial Acinetobacter infections.

Retinoblastoma in adults. Report of three cases and review of the literature.

Retinoblastoma usually presents in children younger than 5 years. To our knowledge, 20 cases of retinoblastoma in adults (older than 20 years) have been reported in the literature. Of 173 patients with histopathologically proven retinoblastoma seen in our institute, three were adults. All the patients had endophytic tumors with vitreous seeds. Ultrasonography did not reveal calcification in two cases. Immunohistochemistry with neuron-specific enolase was used to confirm the diagnosis in two cases. All three patients ultimately required enucleation. None of the patients had been referred with a diagnosis of retinoblastoma. The diagnosis of retinoblastoma should be considered in cases of whitish mass lesion in the fundus of an adult.

Simplified phenotypic tests for identification of Acinetobacter spp. and their antimicrobial susceptibility status.

Acinetobacter spp. have been found to be responsible for an increasing number of nosocomial infections. During a 16-month period, 22 patients hospitalised mainly in the respiratory intensive care unit (RICU), paediatric and other medical wards were investigated either for infection or colonisation by Acinetobacter spp. Of the 45 isolates of Acinetobacter detected among the total of 425 non-fermenters encountered, 24 representative isolates were selected for extended phenotypic identification. Four environmental isolates were also included in the study. These 28 isolates were typed by biotyping and antibiotyping, which helped in delineating the Acinetobacter spp. into 12 phenotypes and two distinct antibiotypes respectively. A sudden increase of cases of acinetobacter infection suggested that three outbreaks during the study period were due to phenotypes 1 and 2 of A. calcoaceticus-A. baumannii complex (Acb). Strains of Acb-complex showed multiple drug resistance and were sensitive only to netilmicin. A comparatively high proportion of resistance to amikacin (48%) was also detected among these strains by the agar dilution method. The RICU environment was recognised as an important reservoir for the resistant outbreak strain (Acb-1) which was probably leading to persistent colonisation and recurrent infections.

Efficacy and safety of apraclonidine in patients undergoing anterior segment laser surgery.

The efficacy of 1.0% apraclonidine (para-aminoclonidine) in preventing the rise of intraocular pressure following anterior segment, laser surgery was evaluated in a randomised double-masked study. Ninety-nine consecutive patients requiring laser treatment of the anterior segment were included in the study. They were randomised into two groups, one receiving 1.0% para-aminoclonidine and the other placebo (vehicle of para-aminoclonidine). The drug caused a statistically significant reduction in pressure after the laser treatment without causing clinically significant side effects such as bradycardia or hypotension.

Tumor necrosis factor allelic polymorphism with diabetic retinopathy in India.

The association of tumor necrosis factor (TNF) with diabetic retinopathy (DR) has been described previously. A total of 207 Asian Indian patients of 15-year duration of type 2 diabetes were identified. This group included (i) 100 patients with DR and (ii) 107 patients without retinopathy (DNR). In this study, we correlated the length of the (GT)n microsatellite di-nucleotide repeat upstream to the promoter region of TNF gene with susceptibility for the development of retinopathy. The microsatellite was polymerase chain reaction amplified and electrophoresed on polyacrylamide gel and silver stained. In our study population, there were 18 alleles ranging from 97 to 131 base pairs (bp). Allele 4 (103 bp) had a higher prevalence (9.81%) in the DNR group compared to that (2.5%) in the DR group (P=0.002). Patients with retinopathy and allele 8 (111 bp) had a tendency to develop proliferative diabetic retinopathy (PDR). In this study of Indian subjects, it is suggested that allele 4 is a low risk allele for developing retinopathy and allele 8 (111 bp) shows an association with PDR.

Corneal endothelial cell density and morphology in normal Indian eyes.

PURPOSE: To describe corneal endothelial cell density and morphology in the Indian population and to compare endothelial cell characteristics in the Indian population with data available in literature for American and Japanese populations. METHODS: Specular microscopy and corneal pachymetry were performed in both eyes of 537 normal Indian volunteers, aged 20-87 years. Parameters studied included endothelial cell density, cell area, coefficient of variation (CV) in cell area and hexagonality. RESULTS: Mean endothelial cell density in the study population was 2,525 +/- 337 cells/mm2. There was a statistically significant decrease in endothelial cell density with age (p < 0.001, correlation -0.387) and the rate of cell loss was 0.3% per year. There was also a statistically significant increase in mean cell area (p < 0.001, correlation 0.362) and CV (p = 0.02, correlation 0.096), and decrease in percentage of hexagonal cells (p = 0.01, correlation -0.127) with increasing age. There was no significant difference in these parameters between fellow eyes of subjects. In all age groups, the mean endothelial cell density was significantly lower than values reported previously in the Japanese population. The values were less than those described in the American population, but the differences were statistically significant only in the 20-30 and 41-50 year age groups. CONCLUSION: Normative data for the endothelium in the Indian population are reported. Endothelial cell density in Indian eyes is less than the values described in the Japanese and American populations.

Detection of pneumolysin in cerebrospinal fluid for rapid diagnosis of Pneumococcal meningitis.

BACKGROUND & OBJECTIVES: Pneumolysin, a toxin produced by Streptococcus pneumoniae is associated with virulence and is found in all invasive isolates. Its role as a diagnostic tool has recently been exploited. Most of the methods used are based on molecular techniques and are not cost-effective. The present study was undertaken to evaluate a simple, rapid and cost-effective method to detect pneumolysin in CSF as a diagnostic test for pneumococcal meningitis. METHODS: A total of 75 CSF samples from children with presumptive diagnosis of acute pyogenic meningitis or encephalitis were subjected to Gram stain, culture and pneumolysin detection by Cowan 1 staphylococcal protein A co-agglutination technique. RESULTS: Pneumolysin was detected in 26(78.8%) of 33 culture proven CSF samples and 4(9.5%) of 42 culture negative samples. Antigen detection by Co-A had a specificity of 90 per cent and a sensitivity of 79 per cent when compared with culture. Compared to Gram stain, pneumolysin Co-A had a specificity and sensitivity of 91.0 and 92.0 per cent respectively. INTERPRETATION & CONCLUSION: Detection of pneumolysin was found to be a simple, low cost antigen detection assay for rapid diagnosis of pneumococcal meningitis, for routine use in the developing countries.

Detection of antipneumolysin in invasive childhood pneumococcal infections.

Antibody levels against pneumolysin, a virulence factor in pneumococcal infections were evaluated by a neutralization test, using crude pneumolysin. A study population of 28 hospitalised children with culture proven pneumococcal meningitis and pneumonia were tested for detection of antipneumolysin antibodies in their serum. Results were compared with age and sex matched controls who were admitted with infections other than pneumococcal. Geometric mean titer (GMT) of antipneumolysin in serum of patients with pneumococcal infections showed a significant difference when compared with controls, GMT of 196.1 and 185.2 were noted in patients with meningitis and pneumonia respectively, in contrast to a titer of 40.32 among controls. A difference of more than 4-fold antibody titers between patients and controls was considered significant. Detection of antipneumolysin in serum can therefore be considered as a useful laboratory investigation in diagnosing invasive pneumococcal infections.

Throat carriage of pneumococci in healthy school children in the Union Territory of Pondicherry.

BACKGROUND & OBJECTIVES: Colonisation of Streptococcus pneumoniae in the throat is common among children the world over. Little is known about the relationship of nasopharyngeal carriage and invasive disease or the way it spreads within the households and close confines. There is a paucity of data on the colonization of Strep. pneumoniae in the throat of healthy children in India. To determine the prevalence of pneumococcal carriage in school children of urban and rural Pondicherry, a study was undertaken. METHODS: Throat swabs of healthy school-going children between 5-10 yr of age were examined for pneumococcal carriage, by standard bacteriological techniques. RESULTS: A prevalence rate of 24.3 per cent was noted. There was no difference in the carriage rate among the rural children when compared to urban children. No age, sex or geographical predilection of pneumococcal carriage was noted. A statistically significant seasonal variation, however, was seen. Carriage rate increased during the colder months and was found to be the highest in the months of March and November. INTERPRETATION & CONCLUSIONS: Strep. pneumoniae circulates in the community among healthy children. Carriage rate is influenced by seasonal variation.

Prevalence of Helicobacter pylori infection in disorders of the upper gastrointestinal tract in south India.

BACKGROUND: Helicobacter pylori (H. pylori) is the most common human infection. Though most individuals are asymptomatic, H. pylori plays a key role in the aetiology of many upper gastrointestinal disorders. The prevalence of duodenal ulcer in south India is high but there are very few reports regarding the prevalence of H. pylori infection in various upper gastrointestinal disorders in south Indians. Therefore, we studied the prevalence of H. pylori infection in upper gastrointestinal disorders in south Indians. METHODS: Three hundred and thirty-five patients with various upper gastrointestinal disorders were included in the study. Seventy-five patients with no gastrointestinal disease based on symptoms and endoscopy were taken as controls. The H. pylori status was determined by the urease test, serology and histology and the prevalence compared between various upper gastrointestinal disorders, with controls and with one another. RESULTS: The prevalence of H. pylori was high in the patients and controls. Duodenal ulcer patients had a significantly higher prevalence compared to controls (p < 0.001) and those with other upper alimentary disorders. There was no significant difference between patients with other disorders and controls nor between each other (p > 0.05). CONCLUSION: The prevalence of H. pylori infection is high in south India. It is closely associated with duodenal ulcer. More population-based studies are required to evaluate the relationship of H. pylori with other disorders of the upper gastrointestinal tract.

Can duodenal ulcer perforation be linked to herpes simplex virus infection?

BACKGROUND: Both Herpes simplex infection and duodenal ulcer recur frequently, tend to remain localized, and show remissions and exacerbations. Published data on a link between the two are contradictory, and there are no data on the association of Herpes simplex infection with perforated duodenal ulcer. METHODS: 187 patients in four groups were studied: group I--controls (n = 35), group II--non-ulcer dyspepsia (n = 35), group III--chronic non-perforated duodenal ulcer (n = 35), and group IV--perforated duodenal ulcer (n = 82). Titers of IgG antibodies against HSV-1 and HSV-2 were determined using enzyme immunoassays. RESULTS: The seropositivity rate for both HSV-1 (80%) and HSV-2 (77%) was high in the control population. Among patients with perforated duodenal ulcer, antibodies against HSV-1 (94%) but not those against HSV-2 (83%), were found more frequently than in groups I and III. HSV-1 seropositivity was significantly higher in patients with a short duration of preperforation symptoms. Absolute titers for both anti-HSV-1 and anti-HSV-2 were higher in patients with perforated duodenal ulcer than in controls and those with chronic non-perforated duodenal ulcer. CONCLUSION: Herpes simplexvirus, especially HSV-1, may have a role in the causation of perforated duodenal ulcers.

Management of giant retinal breaks.

A retrospective study involving 40 eyes of 40 patients with giant retinal break is presented. A comparison is attempted between cases where silicone oil is used and in cases where it was not used. The final success rate was found to be same in the two groups on long term follow-up.

Ocular lesions in AIDS: a report of first two cases in India.

Although 444 cases of AIDS have been officially registered till July 1993 from various parts of India, ocular lesions in these cases have not been reported. Till May 1994, ELISA test for HIV 1 and HIV 2 had been done in 12 cases of suspicious ocular lesions which include viral retinitis, endogenous endopthalmitis and active chorioretinitis. Two patients had seropositivity for HIV 1. Ocular lesions include subretinal yellow mass in the first case and cytomegalovirus retinitis and cotton-wool spots in the second case. These two patients also had several systemic infections which include tuberculosis in both and nocardia in one. To the best of our knowledge, these two cases are the first report of ocular lesions in AIDS from India.

A case control study of senile cataract in a hospital based population.

A case-control study (244 cases and 264 controls) was done during 1986-89 on a hospital based population to evaluate the risk factors associated with the etiology of senile cataract. Patient with age between 40-60 years, visual acuity of 6/9 or less, and presence of lenticular opacity of senile origin were included as cases. Age matched individuals with absence of lenticular opacity made up the controls. Multivariate logistic regression analysis revealed that higher systolic BP and number of meals were significantly (P < or = 0.05) associated with presence of senile cataract; whereas higher weight, education and income, and utilization of cooking water had a significant protective effect against senile cataract. The present study helps the clinician to understand the possible risk factors associated with the development of senile cataract and could be helpful in designing a intervention strategy in future.

Retinal detachment secondary to ocular perforation during retrobulbar anaesthesia.

The clinical characteristics and the retinal breaks associated with rhegmatogenous retinal detachments secondary to accidental globe perforation during local infiltration anaesthesia in five highly myopic eyes are presented. Retinal detachment was total with variable proliferative vitreoretinopathy. The pattern of retinal breaks was rather typical and predictable. Management involved vitreous surgery with internal tamponade by silicone oil in four eyes and perfluoropropane gas in one eye. At the last follow-up, all eyes had attached retina. One eye did not recover useful vision due to possible concurrent optic nerve damage.

Clinical features and virologic studies in viral retinitis.

Viral retinitis is an important infectious disease of the retina which can occur in both healthy and immunocompromized or immunodeficient individuals. The clinical picture and the role of laboratory studies in diagnosis of viral retinitis are still not well-defined. We correlated the clinical picture and virologic study in the serum and vitreous specimens by Enzyme-linked Immunosorbent Assay (ELISA), rapid immunofluorescence technique and culture in five clinically suspected patients of viral retinitis. None of the patients had any evidence of systemic viral infections. In four patients, the virus was detected by immunofluorescence, ELISA or culture from the vitreous sample. Paired serum samples showed elevation of antiviral IgG titre in two cases and high antiviral IgM titre in all cases. Our study evaluated the role of virological investigations of vitreous aspirate and rising antibody titre in the paired serum samples in the diagnosis of active viral retinitis.

Surgery for stage 5 retinopathy of prematurity: the learning curve and evolving technique.

PURPOSE: To describe our experience with management of eyes with stage 5 retinopathy of prematurity (ROP). METHODS: Closed vitreoretinal surgery was done on 96 eyes of patients with stage 5 ROP. Lens was sacrificed in all but one eye. Surgery involved an attempt to clear all preretinal tissue and open the peripheral trough all round. In most instances bimanual surgery under viscoelastic was performed. RESULTS: At last follow up, anatomical success (defined as attached posterior pole) was achieved in 22.5% cases. Significant postoperative problems included reproliferation and secondary glaucoma. Only two infants obtained mobile vision. CONCLUSION: Late identification of disease, lack of prior treatment such as laser or cryo, and higher incidence of narrow-narrow funnel configuration were responsible for the poor surgical results noted in this series. The poor surgical and functional results reemphasize the need for prompt screening and management of infants at risk.

Endophthalmitis caused by anaerobic bacteria.

A retrospective analysis of 22 patients who underwent pars plana vitrectomy for endophthalmitis and had culture-proven anaerobic bacteria, was done. Elimination of infection with attached retina and recovery of ambulatory vision > or = 2/60 were considered as anatomic success and functional success, respectively. Mean follow-up period was 12.7 months (range, 2 to 48 months). Anatomic success was attained in 14 (63.6%) eyes and functional success in 12 (54.6%) eyes. A poor preoperative visual acuity was found to be associated with poor functional outcome (p < 0.046). In endophthalmitis, a routine anaerobic culture of intraocular specimen is recommended.