Search PubMed⌕ Search

Biomedical subjects

R George

Publications and source records attributed to R George.

At least 37 records · Page 2Linked to original sources
PubMed2003

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↗
PubMed2003

Ocular biometry in occludable angles and angle closure glaucoma: a population based survey.

AIM: To compare ocular biometric values in a population based sample of eyes with occludable angles, angle closure glaucoma, and normal subjects. METHOD: 2850 subjects from a population based glaucoma prevalence study underwent complete ocular examination including indentation gonioscopy. Ocular biometry was performed in all subjects classified to have occludable angles (n = 143); angle closure glaucoma (n = 22), and a random subgroup of 419 normal subjects. Ocular biometry readings between the groups were compared and statistically analysed using "t," "z," and Mann-Whitney U tests. RESULTS: The mean age among subjects with occludable angles (54.43 (SD 9.53) years) and angle closure glaucoma (57.45 (8.5) years) was significantly higher (p<0.001) than normal subjects (49.95 (9.95) years). Axial length was shorter (p<0.001) in the occludable angle group (22.07 (0.69) mm) compared to the normal group (22.76 (0.78) mm). Anterior chamber depth (ACD) was shallower (p<0.001) among subjects with occludable angles (2.53 (0.26) mm) than normal subjects (3.00 (0.30) mm). Lens thickness (LT) was greater (p<0.001) in people with occludable angles (4.40 (0.53) mm) compared to normal subjects (4.31 (0.31) mm). No significant difference was noted in axial length, ACD (p = 0.451), and LT (p = 0.302) between angle closure glaucoma and occludable eyes. CONCLUSION: South Indian eyes with angle closure glaucoma and occludable angles seem to have significantly shorter axial lengths, shallower anterior chambers and greater lens thickness compared to the normal group.

Adult↗
PubMed2003

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↗
PubMed2003

Skeletal trauma preceding the development of plasma cell dyscrasia: eight case reports and review of the literature.

Plasma cell dyscrasias are clonal proliferations and accumulations of plasma cells. The etiology of monoclonal neoplasms still remains elusive. A direct correlation between a history of trauma and the development of plasma cell dyscrasias has not been established. Two recent case reports have described plasmacytomas that were diagnosed in patients who suffered injury at the site of plasma cell neoplasms. We report a series of eight patients who stated a history of trauma to the site where plasma cell neoplasms were later diagnosed. The duration from the date of injury to diagnosis ranged from 2 mo to 20 yr. The M:F ratio was 6:2. The median age was 52 (28-75). Multiple myeloma was confirmed in six patients and plasmacytoma without systemic disease in the other two patients. All eight patients had a kappa monoclonal plasma cell population, and all but one had a detectable peripheral kappa light chain. All patients presented with persistent discomfort at the site where they had experienced trauma. Even though this article does not establish a relationship between trauma, and the development of plasma cell dyscrasia, persistent discomfort at a previous trauma site warrants a complete evaluation and consideration for possible plasma cell dyscrasias.

Adult↗
PubMed2002

Problems of classification of Henoch Schonlein purpura: an Indian perspective.

A 2-year prospective study was carried out in which 71 patients with primary cutaneous vasculitis were classified using the American College of Rheumatology (ACR) classification and the Chapel Hill Consensus Conference (CHCC) recommendations for Henoch Schonlein purpura (HSP). The sensitivity of the ACR criteria was 64.8% and that of the CHCC definition 31%. When the ACR criteria were combined with results of direct immunofluorescence (DIF) the sensitivity was 78.9%. The concordance between the two systems was low as only 12 patients fulfilled criteria for both classifications. Although the ACR criteria were found to be more useful in the classification of HSP our data suggest that they need to be modified to include adults with disease. The age at onset of disease was higher than that in the west. Seventy per cent of patients identified by either classification were > 20 years of age. The prevalence of gut involvement, microhaematuria and proteinuria was < 25% in both groups. The sensitivity of histopathology on the other hand was 80.4% and was not influenced by the duration of the lesion. The DIF test was a useful adjunct to histopathology if it was done within 48 h as the yield of a positive test was significantly higher in this group as compared to the patients who had the test done later.

Adolescent↗
PubMed2002

Frequency doubling perimetry in glaucoma.

PURPOSE: To evaluate the validity of frequency doubling perimetry (FDP) in the detection of glaucomatous field defects. METHODS: Group I consisted of 85 eyes of 85 patients with established field defects in automated perimetry, classified by severity of defect. Group II consisted of 48 eyes of 48 control subjects. Both groups underwent Swedish Interactive Testing Algorithm (SITA) standard tests as well as FDP screening strategies (C20-1 and C20-5 and full threshold test). Sensitivity and specificity measures for the FDP tests were calculated using one new and two previously published algorithms. RESULTS: A described scoring system provided the best sensitivity (85.9%) and specificity (95.1%). For moderate and severe cases, the sensitivity improved to 91%. Quantification of the defect did not improve detection. CONCLUSIONS: FDP is a valid screening test for glaucoma. The scoring system described by Patel et al. provided the best results.

Adult↗
PubMed2001

Amplification of AML1 in childhood acute lymphoblastic leukemias.

Amplification of AML1 has been confirmed by fluorescence in situ hybridization analysis in two cases of childhood acute lymphoblastic leukemia. It remains to be elucidated whether this amplification results in up-regulation of the normal AML1 gene product or a potentially mutant AML1 transcript.

Child↗
PubMed2001

Role of frequency doubling perimetry in detecting neuro-ophthalmic visual field defects.

PURPOSE: To report the ability of frequency doubling perimetry to detect "neuro-ophthalmic" field defects, characterize them as hemianopic or quadrantanopic, and differentiate glaucomatous from "other" neuro-ophthalmic field defects. METHODS: Sixty eyes of 30 normal subjects, 50 eyes of 29 patients with glaucomatous defects, and 138 eyes of 103 patients with "typical" neuro-ophthalmic field defects underwent automated perimetry using the Swedish Interactive Threshold Algorithm and frequency doubling perimetry. The sensitivity and specificity for identification of a field defect (frequency doubling perimetry 20-5 and 20-1 screening tests), or to characterize hemianopia/quadrantanopia (full threshold test) were determined. Ability to discriminate glaucomatous defects was determined by comparing frequency doubling perimetry full threshold test in glaucoma to pooled results of normal and neuro-ophthalmic groups. RESULTS: On frequency doubling perimetry, a single point depressed to less than 1% probability had a sensitivity of 97.1% (20-5 test) and 95.7% (20-1 test) for detecting a neuro-ophthalmic visual field defect. The corresponding specificities were 95% using pooled results in normal subjects and patients with glaucoma and "other" neuro-ophthalmic field defects. In 20-5 screening a single abnormal point depressed to less than 2% probability level had a sensitivity of 98.6% (specificity 85%). Two abnormal points in the 20-1 screening depressed to less than 1% probability level had a specificity of 100% (sensitivity 84.8%). In frequency doubling perimetry full threshold, sensitivity and specificity for detection of hemianopia were 86.8% and 83.2%; for quadrantanopia they were 79.2% and 38.6%. The sensitivity and specificity for categorizing a defect as glaucomatous were 86% and 74.7%. CONCLUSIONS: Frequency doubling perimetry is a sensitive and specific test for detecting "neuro-ophthalmic" field defects. The presence of two abnormal points (20-1 screening program) "rules in" the presence of a field defect. A normal 20-5 program (absence of a single abnormal point) almost "rules out" a defect. Frequency doubling perimetry could not accurately categorize hemianopic, quadrantanopic, or glaucomatous defects.

Child↗
PubMed2001

A peptide enzyme linked immunosorbent assay (ELISA) for the detection of human immunodeficiency virus type-2 (HIV-2) antibodies: an evaluation on polymerase chain reaction (PCR) confirmed samples.

BACKGROUND: HIV-1 and HIV-2 infections differ in prognosis, and may also require different prevention and/or treatment approaches. Thus, estimating the true prevalence of HIV-1 and HIV-2 infections, as well as co-infections, is a critical step in controlling the disease. There are a few commercial ELISA and immunoblot kits, which can differentiate between HIV-1 and HIV-2 infections. However, some of these assays overestimate the prevalence of dual infection. Hence, it is necessary to develop assays capable of discriminating between the two infections. OBJECTIVES: To develop a synthetic HIV-2 env based peptide ELISA for the detection of HIV-2 specific antibodies and evaluate its performance on samples from HIV positive individuals previously tested by HIV-1 and HIV-2 PCR and HIV seronegative individuals. STUDY DESIGN: We studied 45 HIV seronegative and 63 HIV infected individuals, including 30 HIV-1 PCR and immunoblot positives, 19 HIV-2 PCR and immunoblot positives, five HIV-1 and two PCR and dual immunoblot positives, two PCR negative but positive for HIV-2 by immunoblot and seven dual immunoblot positives who were only positive for HIV-1 by PCR. RESULTS: All 24 HIV-2 PCR positive samples tested were positive by the peptide assay. Among 30 HIV-1 PCR and immunoblot positive samples, only one (3.3%) showed an absorbance value above the cut off level. The seven dual positive samples by immunoblot (only positive for HIV-1 by PCR) were negative by the HIV-2 peptide ELISA. There was a 100% concordance between HIV-2 PCR and peptide ELISA. The sensitivity, specificity, and the likelihood ratio for the peptide ELISA were 100,94.9, and 19.5, respectively when compared against the PCR findings. CONCLUSIONS: This ELISA, using a specific immunodominant epitope (11 amino acids) from the transmembrane (gp36) portion of the HIV-2 envelope glycoprotein showed a high concordance with PCR findings. This can be considered as a highly sensitive, specific and economically feasible assay for the discrimination of HIV-1 and HIV-2, and may serve as an alternative to HIV-2 PCR in epidemiological studies.

Enzyme-Linked Immunosorbent Assay↗
PubMed2001

Severe valvular and aortic arch calcification in a patient with Gaucher's disease homozygous for the D409H mutation.

Gaucher's disease is an autosomal recessive inherited defect of the lysosomal enzyme glucocerebrosidase, which leads to glucocerebroside accumulation in the reticuloendothelial system. Homozygosity for the D409H mutation has been associated with cardiovascular valvular disease. We present a case of a 17-year-old Palestinian patient who presented with severe aortic and mitral valvular calcification, as well as calcification of the ascending aorta, the aortic arch and the ostia of his coronary arteries. The patient was confirmed to be homozygous for the D409H mutation in the glucocerebrosidase gene. The patient's enzyme assay for glucocerebrosidase activity was 5 nm/h/mg protein (normal 13-22 nm/h/mg). The patient presented with symptoms of dyspnea and chest pain. He had a 6-year history of documented aortic valve calcification by echocardiogram after two of his older brothers died of congestive heart failure and severe valvular calcification. Cardiac catheterization showed a severely calcified aorta with almost no motion of the aortic valve leaflets and severe calcification of the mitral valve and the mitral valvular apparatus. The patient underwent extensive cardiac surgery with aortic and mitral valve replacements and intraoperative findings confirmed calcification of the entire aortic root. Electron microscopy of the valves confirmed the presence of Gaucher's cells. Enzyme therapy with imiglucerase was initiated. The patient is in stable condition, 20 months post-operatively.

Adolescent↗
PubMed2001

Mechanical ventilation during pregnancy using a helium-oxygen mixture in a patient with respiratory failure due to status asthmaticus.

The authors present a 15-year-old with a second trimester intrauterine pregnancy who developed respiratory failure as the result of status asthmaticus and the development of the adult respiratory distress syndrome. Mechanical ventilation was provided with a combination of oxygen and helium to facilitate gas exchange and limit peak inflating pressures. The physiologic basis for helium's potential beneficial effects on gas exchange are reviewed. Previous reports concerning the use of helium during mechanical ventilation as well as the techniques of delivery are discussed.

Adolescent↗
PubMed2001

The effect of weight loss on body image in HIV-positive gay men.

The purpose of this study was to assess how body image may be affected by HIV-related weight loss. Qualitative methodology was used: eight gay men with weight loss of at least 10% self-completed a brief, tailor-made questionnaire and then participated singly in semi-structured audiotaped interviews. Questionnaire analysis showed all but one had avoided social activities in the last two months due to self-consciousness over their emaciated appearance; family visits, meeting new people and meeting up again with people after weight loss were most problematic. Interview analysis revealed that in addition to social considerations, bodily comfort and effectiveness were affected, and participants identified weight loss as a clear sign of disease progression. Weight regain was problematic and food had become a difficult issue for most. These results suggest that in gay men, HIV-related weight loss causes significant emotional and physical problems.

Adult↗
PubMed2001

Nomenclature of major antimicrobial-resistant clones of Streptococcus pneumoniae defined by the pneumococcal molecular epidemiology network.

The emergence of disease caused by penicillin-resistant and multidrug-resistant pneumococci has become a global concern, necessitating the identification of the epidemiological spread of such strains. The Pneumococcal Molecular Epidemiology Network was established in 1997 under the auspices of the International Union of Microbiological Societies with the aim of characterizing, standardizing, naming, and classifying antimicrobial agent-resistant pneumococcal clones. Here we describe the nomenclature for 16 pneumococcal clones that have contributed to the increase in antimicrobial resistance worldwide. Guidelines for the recognition of these clones using molecular typing procedures (pulsed-field gel electrophoresis, BOX-PCR, and multilocus sequence typing) are presented, as are the penicillin-binding profiles and macrolide resistance determinants for the 16 clones. This network can serve as a prototype for the collaboration of scientists in identifying clones of important human pathogens and as a model for the development of other networks.

Anti-Bacterial Agents↗
PubMed2001

Tumor-induced sensitivity to apoptosis in T cells from patients with renal cell carcinoma: role of nuclear factor-kappaB suppression.

Antitumor immunity fails to adequately develop in many cancer patients, including those with renal cell carcinoma (RCC). A number of different mechanisms have been proposed to explain the immune dysfunction observed in cancer patient T cells. Here we show that T cells from RCC patients display increased sensitivity to apoptosis. Tumor-infiltrating lymphocytes (TILs) display the most profound sensitivity, because 10-15% of those cells are apoptotic when assessed by terminal deoxynucleotidyltransferase-mediated nick end labeling in situ, and the number of apoptotic TILs further increases after 24 h of culture. Peripheral blood T cells from RCC patients are not directly apoptotic, although T lymphocytes derived from 40% of those individuals undergo activation-induced cell death (AICD) upon in vitro stimulation with phorbol myristate acetate and ionomycin. This is in contrast to T cells from normal individuals, which are resistant to AICD. TILs and peripheral blood T cells from RCC patients also exhibit impaired activation of the transcription factor, nuclear factor (NF)-kappaB. Additional findings presented here indicate that the heightened sensitivity of patient T cells to apoptosis may be tumor induced, because supernatants from RCC explants sensitize, and in some instances directly induce, normal T cells to apoptosis. These same supernatants also inhibit NF-kappaB activation. RCC-derived gangliosides may represent one soluble tumor product capable of sensitizing T cells to apoptosis. Pretreatment with neuraminidase, but not proteinase K, abrogated the suppressive effects of tumor supernatants on both NF-kappaB activation and apoptosis. Additionally, gangliosides isolated from tumor supernatants not only inhibited NF-kappaB activation but also sensitized T cells to AICD. These findings demonstrate that tumor-derived soluble products, including gangliosides, may contribute to the immune dysfunction of T cells by altering their sensitivity to apoptosis.

Apoptosis↗
PubMed2001

A pilot study of HTLV-I infection in high-risk individuals & their family members from India.

BACKGROUND & OBJECTIVES: Human T lymphotropic virus-I (HTLV-I) has been associated with adult T cell lymphoma/leukemia (ATLL). There are Indian studies on HTLV-I infection among people with sexually transmitted infection, but no large study has been conducted on individuals with haematological malignancies. In this group of individuals, serology is known to under-diagnose HTLV-I infection. This study was carried out to identify serologically and where possible with molecular techniques, HTLV-I infection in individuals with haematological malignancies. To understand the modes of transmission, family members of individuals with proven HTLV-I infection were also studied. Individuals with sexually transmitted infection (STI), blood donors and pregnant women were also studied. METHODS: Particle agglutination test was used to detect antibody to HTLV-I. HTLV genome was amplified by polymerase chain reaction (PCR) and detected with probes by digoxiginin (Dig) ELISA. RESULTS: There was no serological evidence of HTLV-I infection among the healthy blood donors and pregnant women studied. High prevalence of anti-HTLV-I antibody was identified in the patients with haematological malignancies (8 of 86 patients, 9.3%) and a lower prevalence in individuals with STI (8 of 670 individuals, 1.2%). In the STI group, all 8 individuals seroreactive to HTLV-I were coinfected with human immunodeficiency virus (HIV). In the group with haematological malignancies, three of 22 (13.6%) patients with leukemia, 3 of 11 (27.3%) with cutaneous T-cell lymphoma (CTCL) and 2 of 53 (3.8%) with lymphoma were reactive for anti-HTLV-I antibody. In this group, PCR identified all the seroreactive individuals tested. There were also seronegative infected individuals who were only identified by PCR. There was also a large number of seronegative family members who were only positive by PCR. INTERPRETATION & CONCLUSION: The study revealed a strong disease association of HTLV-I with haematological malignancies and evidence for both horizontal and vertical transmission of the infection in the Indian population. HTLV-I infection appears to be common among family members of individuals with HTLV-I associated haematological malignancies.

Adult↗
PubMed2001

Interpreting automated perimetry.

Visual field testing is mandatory for many ophthalmic conditions including glaucoma. The current gold standard for visual field testing is automated perimetry. In this article we familiarize the reader with the components of an automated perimetry printout. We describe a systematic approach that leads to a thorough interpretation of the printout. With the help of examples the reader should be able to learn to identify a normal field, detect the presence of a field defect, determine whether it is due to glaucoma, and establish progression, if any.

Humans↗
PubMed2000

Invasive pneumococcal disease in England and Wales: vaccination implications.

Knowledge of the epidemiology of invasive pneumococcal disease (IPD) will aid in planning the use of pneumococcal vaccines. A United Kingdom (UK)-based surveillance in England and Wales (1995-1997) of 11,528 individuals with IPD and a local enhanced surveillance in the Oxford (UK) area (1995-1999) have been analyzed. IPD has a high attack rate in children, with 37.1-48.1 cases per 100,000 infants <1 year old per year, and in older persons, with 21.2-36.2 cases per 100,000 persons >65 years old per year, for England, Wales, and Oxford. The 7-valent conjugate vaccine includes serotypes causing < or =79% of IPD in children <5 years old, but only 66% in adults >65 years old. The data also indicate that IPD varies by serotype, age, and country, emphasizing that the epidemiology of IPD is heterogeneous and requires continued surveillance.

Adolescent↗