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S Sharma

Publications and source records attributed to S Sharma.

At least 559 records · Page 31Linked to original sources
PubMed1998

Tolerance and determinant hierarchy.

The overall T cell response to a multideterminant antigen consists of the sum of responses to a limited number of different determinants on the protein. Antigen-presenting cells (APCs) are crucial in delimiting the determinants on the protein to which a response will be mounted. This influence is apparent at two levels. First, the determinants that are generated and displayed by APCs in the thymus are pivotal in shaping the T cell repertoire that will be available for responding to antigen determinants in the periphery. Second, antigen processing affects the selection of determinants that become displayed by the various peripheral APC populations that are involved in inducing and promoting a T cell response. We have studied the effect of the display hierarchy on tolerance induction to individual determinants in transgenic mice expressing different serum levels of hen egg lysozyme. We have also analysed aspects of the processing machinery that contribute to shaping the hierarchy of determinant display on MHC class II molecules: proteolysis and reduction of disulfide bonds.

Amino Acids, Diamino↗
PubMed1998

Effects of literacy and education on measures of word fluency.

As part of a cross-national study of dementia epidemiology, two types of verbal fluency tasks were administered to three groups of subjects, varying in level of literacy and education, recruited from the rural district of Ballabgarh in northern India. Subjects were asked to list items in a given semantic category (animals; fruits) or words beginning with a given sound (the phonemes /p/ and /s/) the latter being a minor modification of the more familiar initial letter fluency task in view of the high prevalence of illiteracy in Ballabgarh. Analysis of variance revealed main effects of education and task with a task by education interaction such that education had a greater effect on initial sound fluency than on category fluency. The results are discussed in terms of their implication for the design of cross-cultural studies and the evidence that the ability to segment speech into phonemic units is dependent on literacy.

Adult↗
PubMed1998

Foetal liver infusion in a chronic myeloid leukemia patient with busulphan toxicity.

A 36-year-old man suffering from chronic myeloid leukemia (in chronic phase) was initially treated with busulphan. At the end of 6 months of follow-up he developed bone marrow aplasia. He was given single foetal liver infusion therapy. The patient recovered fully from aplasia. He continued in chronic phase for more than 7 years with intermittent busulphan therapy.

Adult↗
PubMed1998

Comparison of methods of eye protection under general anaesthesia.

PURPOSE: To compare and assess the efficacy of eye ointment and adhesive tape for protection of eyes under general anaesthesia. METHODS: One hundred and fifty patients (300 eyes) undergoing general anaesthesia for > 90 min for non-ophthalmic procedures were divided randomly into three groups (C, T & O). Eyes in group C were left as control, in group T hypoallergen tape was applied and in group O chloromycetin ointment was used. In all eyes basal tear production and visual acuity was assessed and corneal examination was carried out after fluorescein staining both before and after surgery. All the patients were subjected to a conventional general anaesthesia technique. RESULTS: General anaesthesia reduced basal tear production irrespective of the method of eye protection used (P < 0.0001). The overall incidence of corneal epithelial defects was 10%, of which 90% occurred in the control group, 6.6% in the tape and 3.3% in the ointment group. There was no difference between pre and post operative visual acuity (P : NS). Corneal injuries were more common in the dependent eye in the lateral position and the incidence of corneal epithelial defects did not alter with increase in duration of surgery. CONCLUSION: During general anaesthesia eyes need protection either by tape or ointment as incidence of corneal injuries is greater in unprotected eyes.

Adhesives↗
PubMed1998

Practical issues in cognitive screening of elderly illiterate populations in developing countries. The Indo-US Cross-National Dementia Epidemiology Study.

The study of the epidemiology of dementia, specifically Alzheimer's disease, in developing countries requires specialized instruments and personnel. Cultural and sub-cultural differences among populations are highly relevant to the design of such instruments. Over and above the cultural issues, it is widely recognized that low education and illiteracy pose considerable challenges to reliable and valid cognitive screening. The overall objectives of the Indo-US Cross-National Dementia Epidemiology Study were: a) to determine the prevalence and incidence of, and risk factors for, Alzheimer's and other dementias in a defined Indian community; and b) to compare these results with those found in a defined American community. To achieve these epidemiological objectives, our first task was to develop, systematically and empirically, suitable cognitive and activities assessment screening instruments for use in India, which would 1) be culturally fair, psychometrically sound, and valid for a population with little or no education; 2) be optimally sensitive and specific for dementia; and 3) allow not only the identification but also the more detailed characterization of dementia, and of normal and abnormal cognitive aging. In this paper we address the practical issues involved in the development and administration of the modified cognitive screening battery in our rural Indian context.

Aging↗
PubMed1998

Phenotypic expression of hemoglobin A2 in beta-thalassemia trait with iron deficiency.

Iron status was estimated in 463 heterozygous beta-thalassemics to delineate the effect of iron deficiency on the expression of hemoglobin A2 (HbA2) in these patients. One hundred and twenty-six (27.2%) patients with the trait were iron deficient. These iron-deficient patients had a significantly (p < 0.0002) higher prevalence of anemia (90.5%) compared with iron-replete patients with the trait (71.5%). The mean hemoglobin (Hb) concentration, MCV, and MCH were significantly (p < 0.0001) lower in patients with beta-thalassemia traits (BTT) who had iron deficiency than in those without iron deficiency. Mean RBC count and MCHC did not differ in the two groups. Mean HbA2 was not significantly different in the two groups of patients with the trait and was elevated (>3.5%) in all but one heterozygote investigated. Mean HbA2/cell was significantly (p < 0.05) lower in BTT patients with iron deficiency than in patients without iron deficiency. The presence of iron deficiency did not preclude the detection of BTT in this population. The effect of iron deficiency in BTT was apparent as a significant lowering of the Hb concentration and an increased prevalence of anemia. Iron therapy is warranted for BTT patients with iron-deficiency traits and would help to significantly raise their Hb concentration. The elevation of HbA2 was striking and could be used with reliability in making the diagnosis of BTT even in the presence of iron deficiency.

Anemia, Iron-Deficiency↗
PubMed1998

Serial echocardiographic assessment of left atrioventricular valve function in young children with ventricular inversion.

BACKGROUND: Regurgitation of the morphologic tricuspid valve (mTV) adversely influences the clinical outcome of patients with ventricular inversion. METHODS AND RESULTS: To evaluate the mTV regurgitation (TR), we reviewed serial echocardiograms for 25 children with ventricular inversion, with and without congenital heart surgery. Patient age was from 6 months to 19.0 (median 5.8) years. Follow-up was from 5 months to 15.0 (median 4.1) years. Initial assessment was at a median 65 days of age; only nine (36%) of 25 had TR. At follow-up, 16 (64%) of 25 had TR, with two requiring valve replacement. The mTV was abnormal in 16 (64%) of 25 patients and in 11 (69%) of 16 TR worsened compared with one (11%) of nine patients with "normal" mTVs. Nine (36%) of 25 had Ebstein's anomaly, three of whom had new TR develop. Of 17 patients who underwent cardiac surgery, 10 (59%) had new or increased TR compared with three (37%) of eight nonoperative patients. After intracardiac repairs, eight (73%) of 11 had increased TR develop compared with two (33%) of six patients after extracardiac surgery. CONCLUSIONS: (1) Young patients with ventricular inversion had TR develop during follow-up, without cardiac surgery. (2) Surgical patients with intracardiac repairs had more TR develop than with extracardiac procedures. (3) Anatomic abnormalities of the mTV were associated with an increased risk of TR developing. These data help elucidate the factors that affect the development of TR in patients with ventricular inversion.

Adolescent↗
PubMed1998

Effect of bolus epinephrine on systemic hemodynamics in canine anaphylactic shock.

OBJECTIVE: Epinephrine (Epi) is considered to be the drug of choice for anaphylactic shock (AS). However, the benefit of this drug on improving systemic hemodynamics in AS has never been shown. We used a canine ragweed model of AS to determine if an intravenous bolus of Epi hastened the recovery of hemodynamics and modified mediator release (Med) compared with no treatment (NT). METHODS: In one protocol (n = 8), the effects on hemodynamics of two intravenous doses of Epi (0.01 and 0.025 mg/kg) were examined for 3 h postshock in respective studies approximately three weeks apart under pentobarbital anesthesia in the same animal. In five other dogs, left ventricular (LV) mechanics were additionally determined by sonomicrometric techniques to determine changes in contractility as defined by the preload recruitable stroke-work (SW) relationship. RESULTS: Compared with NT values, Epi treatments produced only transient increases in mean arterial pressure (MAP) and cardiac output (CO) post-challenge. By 20 min postshock, CO in the Epi studies were generally lower (p < 0.05) and BP was not different from NT values. With Epi treatment, SW was reduced for a given LV end-diastolic volume compared with the control study. Epi treatments also caused relatively higher plasma thromboxane B2 concentrations postshock. CONCLUSION: Our findings indicate that, when given immediately postshock, bolus-Epi did not hasten recovery and caused impairment in LV mechanics in canine AS.

Adrenergic alpha-Agonists↗
PubMed1998

Morphological mural changes in the aorta in non-specific aortoarteritis (Takayasu's arteritis): assessment by intravascular ultrasound imaging.

OBJECTIVE: Non-specific aortoarteritis (Takayasu's arteritis) is a panarteritis of unknown aetiology which primarily involves the vessel walls. The imaging morphology of wall abnormalities has been infrequently studied and their intravascular ultrasound appearance is not reported in the literature. METHOD: We studied this morphology by intravascular ultrasound in nine patients in whom the diagnosis of Takayasu's arteritis was made by clinical and angiographic criteria. Intravascular ultrasound was performed by the transfemoral route. Images of the aorta were obtained in each patient. Qualitative and quantitative analysis was performed. RESULTS: All procedures were successful, without complication. Typical findings included thickening and altered echogenicity of the media, adventitia and peri-arterial tissues. The inner echogenic layer was thin. Pliability of aortic walls was lost in stenotic segments. Aortic calcification was seen in one patient. The aortic wall thickness was 0.17-0.58 cm. Angiograms showed skip areas of aortic involvement. Intravascular ultrasound showed wall changes even in the skip areas which were normal at angiography. CONCLUSION: Intravascular ultrasound shows changes in the aortic wall morphology in non-specific aortoarteritis. Our findings suggest that this disease involves contiguous aortic segments, producing wall and luminal changes in some areas and only wall changes in intervening areas.

Adolescent↗
PubMed1998

Can pulmonary venous hypertension be graded by the chest radiograph?

AIM: The chest radiograph is widely used for the diagnosis and follow-up of patients with pulmonary venous hypertension (PVH) caused by rheumatic heart disease. Observer accuracy and interobserver agreement on the radiographic diagnosis of PVH is rarely assessed. We have studied this accuracy and agreement in 120 consecutive patients. METHODS AND RESULTS: Patients were selected on the basis of mean pulmonary capillary wedge pressures (PCWP) obtained in the basal state. A chest radiograph was obtained within the 24 h before catheterization and was assessed by two observers blinded to the diagnosis and PCWP. PVH was graded as absent (PCWP < 12 mmHg); mild (PCWP 12-19 mmHg; redistribution of blood flow and hilar haze); moderate (PCWP 20-25 mmHg; septal oedema, pleural effusion) and severe (PCWP > 25 mmHg; alveolar oedema). Observer and interobserver agreement was quantified by using the Kappa (kappa) statistic. The radiological assessment coincided with the measured PCWP in 52% of the patients according to observer 1 and 43% of the patients according to observer 2 (kappa 0.36 and 0.24), indicating poor agreement with haemodynamic values. Interobserver agreement was poor (kappa 0.3-0.35). Observer accuracy and interobserver agreement increased when the radiographic criteria were used to distinguish patients with normal PCWP from those with abnormal pressures when 85% and 78% of radiographs were correctly classified (kappa 0.6 and 0.5) by observers 1 and 2, respectively. Overall agreement was significant (kappa 0.6). In differentiating patients with a PCWP > 20 mmHg from those with a PCWP < 20 mmHg, 78% and 75% of radiographs were correctly classified, giving kappa values of 0.6 and 0.5. Overall observer agreement was significant (kappa 0.6). CONCLUSION: The chest radiograph is useful in detecting the presence of PVH and in distinguishing significant elevations in PCWP (> 20 mmHg) from mildly elevated PCWP. There is poor correlation between haemodynamic and radiographic findings when more precise grading of the severity of PVH is attempted.

Adolescent↗
PubMed1998

Dimethyl sulfoxide (DMSO) causes a reversible inhibition of telomerase activity in a Burkitt lymphoma cell line.

INTRODUCTION: Telomerase is an enzyme that is required for maintenance of telomeres. This enzyme has been shown to be present in germline tissues and majority of tumors and tumor cell lines. The regulation of telomerase is an area of active investigation in different models because, potentially, inhibition of this enzyme could be important in cancer therapy. To study the regulation of this enzyme in lymphoma cell lines, we used DMSO to produce a reversible G0/G1 arrest in Raji cell line, as shown earlier [Sawai M, Takase K, Teraoka H, Tsukada K. Reversible G1 arrest in the cell cycle of human lymphoid cell lines by dimethyl sulphoxide. Exp Cell Res 1990;187:4-10]. METHODS: In this study, we use a highly quantifiable conventional (non-amplified) assay to study the effect of DMSO on telomerase. In addition, we studied cellular proliferation and cell cycle profiles of the cells treated and, subsequently, released from DMSO induced blockage. RESULTS: In this model, DMSO reversibly inhibited telomerase activity that could be restored after release from the blockage. The inhibition of telomerase seems to parallel cellular proliferation and it appears that telomerase is regulated upon entry into the cell cycle. This view is consistent with other previously published views on relationship of telomerase with exit from cell cycle. CONCLUSION: Our observations demonstrate a novel effect of DMSO on cellular mechanisms in Raji cell line. It may provide an attractive model to further study regulation of telomerase in this cell line.

Burkitt Lymphoma↗
PubMed1998

Microbial keratitis in children.

OBJECTIVE: Microbial keratitis is a major cause of corneal blindness worldwide. This problem is particularly relevant to children, because most of their visual life is ahead of them, and they are uniquely at risk for irreversible ocular deficits, such as those resulting from amblyopia. The objective of this study was to determine the etiologic agents and predisposing factors in childhood infectious keratitis and to examine the outcome of treatment in terms of structure and visual acuity. DESIGN: The study design was a retrospective cases series. PARTICIPANTS: The authors studied 113 eyes in 107 children 16 years of age and younger who were treated for (nonviral) microbial keratitis at the LV Prasad Eye Institute in Hyderabad, India, during the 4.5-year period between February 1, 1991, and June 30, 1995. INTERVENTION: The patients who met the following criteria were included in the study: (1) corneal stromal infiltrate was present on slit-lamp examination; and (2) a corneal scraping was taken at the time of examination for suspected microbial keratitis. MAIN OUTCOME MEASURES: Etiologic micro-organisms, predisposing factors, treatment method, structural treatment outcome, and visual acuity treatment outcome of the infectious keratitis episode were measured. RESULTS: The principal predisposing factors identified in this study were trauma (21.2%), ocular disease (17.7%), systemic disease (15.9%), and prior penetrating keratoplasty in the same eye (8.8%). Vitamin A deficiency was an important factor within the category of severe systemic disease, and contact lens wear was not involved in any of the cases. A total of 85 organisms were isolated in cultures of corneal scrapings from 64 (56.6%) of the 113 cases. Staphylococcus species (43.7%), Streptococcus pneumoniae (18.8%), and fungi (17.2%) were the most common isolates. Eighteen eyes (15.9%) required surgery, and 28 (36.4%) of the 77 patients on whom visual acuity was assessed at last follow-up achieved an unaided visual acuity of 20/60 or better at last follow-up. CONCLUSION: This work represents the largest recent study on childhood (nonviral) microbial keratitis, its management, and treatment outcomes. In this study, amblyopia is highlighted as a potentially significant sequela of childhood microbial keratitis. Identification of the appropriate predisposing factors, etiologic microbial organisms, and treatment outcome from this study may aid in early recognition and treatment of microbial keratitis in children.

Adolescent↗
PubMed1998

A comparison of laser photocoagulation with trans-scleral cryotherapy in the treatment of threshold retinopathy of prematurity.

OBJECTIVE: The goal of this study was to determine whether there was a significant difference between the visual outcomes of eyes with threshold retinopathy of prematurity (ROP) treated with trans-scleral cryotherapy compared to those treated with laser photocoagulation. DESIGN: Extended follow-up study of a prospective, randomized clinical trial. PARTICIPANTS: Fifty-two patients with bilateral threshold ROP participated. Follow-up data were available for 25 of these patients. INTERVENTION: Patients were randomized to receive cryotherapy in one eye and laser photocoagulation in the other eye. MAIN OUTCOME MEASURES: The best-corrected visual acuity of each eye was measured. Best-corrected visual acuities of 20/50 or better were classified as "good" clinical outcomes, whereas those 20/60 or worse were considered "poor" outcomes. A secondary outcome of this study was the spherical equivalent (SE) of each eye's most recent refraction. RESULT: At an average follow-up point of 5.8 years (range, 4.3-7.6 years), the odds that an eye treated with laser had a good clinical outcome were 6.91 times greater than for eyes treated with cryotherapy (95% confidence interval, 1.70-28.0; n = 21). Additionally, the laser-treated eyes were less myopic with a mean SE of-3.05 diopters compared to a mean SE of -5.08 diopters for the cryotherapy-treated eyes (P = 0.0072, n = 23). CONCLUSION: The authors' study suggests that laser photocoagulation for threshold ROP was more likely to result in a good clinical outcome with better final visual acuity and less myopia compared to cryotherapy treatment.

Child↗
PubMed1998

Gene therapy for lung cancer.

Gene therapy has received considerable attention and some speculation as to its value. Although few patients have been treated, the preliminary results of the phase I lung cancer gene therapy clinical trials are very promising. Clinically relevant basic research in the molecular pathogenesis and immunology of lung cancer is progressing. As improved vector technologies are developed, new opportunities will be available to initiate lung cancer gene therapy trials that are based on a more detailed understanding of lung cancer biology. In conclusion, although important biologic and technical questions remain unanswered, recent research suggests that gene therapy will have a profound impact on lung cancer treatment.

Animals↗
PubMed1998

Quantitative estimates of ABH secretion in saliva of human twins.

Blood and saliva samples of 122 like-sexed twin pairs (65 MZ and 57 DZ) living in Chandigarh (India) were analyzed for ABH polymorphism. The results indicated that ABH secretions were independent of ABO blood groups though there was an indication of higher incidence of non-secretors among 'O' blood group twin individuals. No significant differences were observed between twins and singletons in secretor gene frequency estimates. The quantitative data revealed that mean titre scores for H substances were lower than that for A and B substances. F test contrasting intra-pair variance between zygosities for ABH quantitative secretions was highly significant indicating stronger genetic component of variation. The results suggested that quantitative assay of ABH secretions would be a better indicator for zygosity determination than mere qualitative differentiation.

ABO Blood-Group System↗