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Biomedical subjects

S M Sharma

Publications and source records attributed to S M Sharma.

At least 19 recordsLinked to original sources
PubMed1997

Transthoracic echocardiography in young patients with acute retinal arterial obstruction. RECO Study Group. Retinal Emboli of Cardiac Origin Group.

OBJECTIVE: To report the transthoracic echocardiographic findings in young patients presenting with acute retinal arterial obstruction, given their clinical risk status for cardioembolic disease. DESIGN: Case series. SETTING: Four North American tertiary hospital centres. PATIENTS: Eleven patients less than 45 years of age presenting with acute retinal arterial obstruction who underwent transthoracic echocardiography. OUTCOME MEASURES: Anticoagulation therapy or cardiac surgery. RESULTS: Echocardiography showed abnormalities in five patients (45%). Five of the 11 patients were at high risk for cardioembolic disease on the basis of a history of risk factors or the presence of a cardiac murmur on presentation, or both. Three (60%) of the five had abnormal findings on echocardiography; all three required anticoagulation therapy or cardiac surgery. Of the six patients at low risk two (33%) had abnormal echocardiograms; neither required anticoagulation therapy or surgical intervention. CONCLUSIONS: All the patients who required anticoagulation therapy or cardiac surgery based on the findings on transthoracic echocardiography were deemed to be at high risk for cardioembolic disease. This emphasizes the importance of clinical risk stratification in the systemic evaluation of young patients presenting with acute retinal arterial obstruction.

Acute Disease↗
PubMed1996

Transthoracic echocardiographic findings in patients with acute retinal arterial obstruction. A retrospective review. Retinal Emboli of Cardiac Origin Group.

OBJECTIVE: To assess the importance of cardio-embolic (emboli of cardiac origin) risk stratification in the cardiac evaluation of patients with acute retinal arterial obstruction. DESIGN: A multicenter retrospective study of patients with acute retinal arterial obstruction who underwent transthoracic echocardiography. SETTINGS: Four North American hospital centers. PATIENTS: One hundred patients with acute retinal artery obstruction in whom transthoracic echocardiography was performed. MAIN OUTCOME MEASURE: Anticoagulation or cardiac surgery based on abnormalities detected on transthoracic echocardiography. Transesophageal echocardiographic results were not evaluated, as they were rarely performed in our centers. Thus, the outcome measure was determined solely by the results of transthoracic echocardiography. RESULTS: Patients were divided into high- and low-risk groups based on their history of cardioembolic risk factors or the presence of a cardiac murmur. Of 67 patients with no risk factors, 41 (61%) had normal echocardiographic study results and 26 (39%) had abnormalities detected, of whom only 1 (1.5%) received anticoagulation or cardiac surgery. The presence of 1 or more cardio-embolic risk factors increased the likelihood for anticoagulation or cardiac surgery 25 times (odds ratio = 25; 95% confidence interval = 3.04-217.02). Although this result is clinically and statistically significant, it is possible that abnormalities missed by transthoracic methods may have been detected by transesophageal technology. CONCLUSIONS: In patients with acute retinal arterial obstruction at low cardioembolic risk, transthoracic echocardiography resulted in anticoagulation or cardiac surgery in 1 (1.5%) of 67 patients. Routine transthoracic echocardiography without follow-up transesophageal echocardiography for patients identified as having abnormalities such as left ventricular hypertrophy or mitral annular calcification and who are at low cardioembolic risk rarely resulted in anticoagulation or cardiac surgery.

Acute Disease↗
PubMed1994

Significance of antithyroglobulin autoantibodies in differentiated thyroid carcinoma.

The incidence of antithyroglobulin autoantibodies (ATA) was 17.7% in 963 patients (who attended the clinic from 1981 to 1990) with differentiated thyroid carcinoma (DTC). Another 12 patients developed ATA for a transient period after the treatment with radioiodine. The prevalence of ATA in females (21.5%, 123/572) was significantly higher (p < 0.001) than that seen in males (12.0%, 47/391). Age-dependent occurrence of ATA was not seen for the various age decades. The ATA was more prevalent (p < 0.01) with the papillary type of tumor (118/564) as compared to the follicular variety (51/398). ATA did not influence the metastatic spread of the tumor at the initial presentation (105/170 for the ATA-positive group and 445/793 for the ATA-negative group). However, within the group with metastases, 82.9% (87/105) of patients had local spread into the neck in the presence of ATA, which was significantly higher (p < 0.01) than that seen for patients without ATA (63.8%, 284/445). For assessment of the influence of ATA on the outcome of the disease, the data from 222 patients (46 positive and 176 negative for ATA), with a minimum follow-up of 5 years (mean follow-up of 7.4 years), was considered suitable for analysis. The outcome of the disease was comparable in the presence and the absence of ATA (38/46 and 137/176 patients became disease-free in ATA-positive and -negative groups, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Hypoglycemia as a possible factor in the induction of vasovagal syncope.

Glucose level was estimated in capillary blood of 16 patients, who had vasovagal syncope during exodontia with local anaesthesia. One consistent finding was the low blood sugar level in all patients during syncope, as compared with the level 1 hour after recovery. Hypoglycemia can be induced by parasympathetic activation; this may be the product of reflex conditioning. Modest lowering of blood sugar levels can also act in synergy with hypotension and hypocapnea to induce loss of consciousness. Psychogenic syncope may be mediated through a mechanism involving hypoglycemia. Reflex conditioning perhaps accounts for the small but consistent fraction of the adult population who have repeated fainting episodes.

Adolescent↗
PubMed1991

Differentiated thyroid carcinomas in children and adolescents.

An analysis of differentiated thyroid carcinomas in children and adolescents revealed that the incidence was 3.05% of total number of patients with differentiated thyroid cancers in all age groups. There was a female preponderance. The incidence of papillary, follicular and papillary with follicular elements was equal. There were no papillary carcinomas observed in children younger than 10 years. The predominant mode of presentation was a solitary nodule of thyroid and some of them had associated cervical adenopathy. A considerable number presented with only cervical adenopathy. The incidence of nodal metastases was 50% at time of presentation and lung involvement was present in 15% of children at the time of diagnosis. Radioiodine treatment was given in 70% of children. Ablation was achieved in 86% of patients given two doses of radioiodine (200 millicuries). The more resistant cases were those with lung and nodal metastases. There was complete ablation in 100% with only residual thyroid tissue, 83% in those with associated nodal metastases, and 57% in those with lung involvement. Average duration of follow-up was 10.3 years (range, 2 to 19 years). Recurrence rate or relapse was observed in 8.5% and was in the regional nodes. There was no recorded mortality due to the disease.

Adenocarcinoma↗
PubMed1990

TSH receptors in human thyroid tumours.

To evaluate the binding of human TSH (h-TSH) to various human thyroid tumours using radio receptor assay technique, 26 thyroid tumour specimens were examined. Five specimens did not show displacement by stable h-TSH. A wide variation was observed in B0, non specific binding, affinity and capacity of TSH in all the tumours examined. The Scatchard analysis of the binding of h-TSH to thyroid membranes suggested the presence of the receptors in 57.7 per cent (15 of 26, Ka much greater than 10(9)) and more than one component in 46 per cent (12 of 26) of the tumours studied. There was no consistent pattern of the binding of TSH for thyroid tissue with respect to its pathology. However, with 35 pairs of observations log affinity appeared to be linearly related to log capacity with a slope -0.95, intercept 9.96 and r value -0.93.

Binding Sites↗
PubMed1988

Clinical evaluation of 99mTc(V)-dimercapto succinic acid (DMSA) for imaging medullary carcinoma of thyroid and its metastasis.

99mTc(V)-DMSA kits developed by the Radiopharmaceutical Division, Bhabha Atomic Research Centre, have been evaluated for potential use in scanning medullary carcinoma of the thyroid and its metastases. There were 15 patients with proved medullary carcinoma and 6 patients with other differentiated thyroid carcinoma. Amongst the 15 patients with medullary carcinoma, 12 (80%) showed positive localisation either in the primary or one or more metastatic sites. None of the six patients with carcinoma other than medullary showed increased concentration of 99mTc(V)-DMSA. Of the 37 known metastatic sites in 15 patients with medullary carcinoma, 24 showed concentration of 99mTc(V)-DMSA (64.9%). In addition, 99mTc(V)-DMSA concentration was seen in 14 sites where no evidence of metastasis was revealed. The incidence of 99mTc(V)-DMSA concentration in soft tissue and bone metastasis was similar.

Adult↗
PubMed1988

Monoclonal antibodies to human thyroglobulin: production and characterization.

Human thyroglobulin was used as an antigen for the development of monoclonal antibodies by the hybridoma technique. Spleen cells of BALB/c mice immunized with human thyroglobulin were fused with SP2/0 mouse myeloma cells. Seven clones secreting specific monoclonal antibodies to thyroglobulin were established. Two of these monoclonal antibodies have been purified and characterized. Their equilibrium association constants (Ka) as determined by Scatchard analysis were 0.24 X 10(11) L/M and 1.4 X 10(11) L/M respectively. The specificity of both these antibodies was validated by immunohistochemical staining of human tissues (normal human thyroid, brain, salivary gland, skeletal and smooth muscle, mucous membrane, parathyroid, adrenal) obtained from autopsy material. Only follicles and follicular cells of thyroid tissue were stained by both the monoclonal antibodies. H10 I monoclonal antibody was used for constructing a standard curve for in vitro immunoassay using a solid phase ELISA technique. The minimum amount detectable was 7.8 ng/ml. Thirty six sera from patients of various thyroid disorders were evaluated using ELISA and compared with conventional RIA. A good agreement was seen (r = 0.92) between the two techniques. These specific monoclonal antibodies may prove to be valuable for in vitro immunoassays and in vivo immunoscintigraphy.

Antibodies, Monoclonal↗
PubMed1987

Preparation and evaluation of 99mTc(V)-DMSA complex: studies in medullary carcinoma of thyroid.

Consequent to the promising results reported with 99mTc(V)-DMSA for imaging certain types of soft tissue tumors, we have developed methods to prepare this radiopharmaceutical in three ways: from freshly prepared reagents, through the use of a two component kit and use of the standard renal DMSA kit by a modified recipe. The 99mTc(V)-DMSA complex has been subjected to paper electrophoretic and chromatographic procedures and also biodistribution studies. The distinctly different behaviour of this new product compared to that of the well known renal DMSA complex has been clearly established. Scintiimaging in a preliminary clinical trial in patients with medullary carcinoma of the thyroid has been encouraging.

Carcinoma↗
PubMed1986

Influence of initial large dose on subsequent uptake of therapeutic radioiodine in thyroid cancer patients.

Fifty-two patients with differentiated thyroid cancer, following thyroidectomy were studied by administering a quantity of up to 5 mCi of [131I]sodium iodide. In most of these patients, radioiodine uptake values obtained with the subsequent therapeutic dose were markedly lower than those observed with the initial doses. This observation was verified in seven of the patients with differentiated thyroid cancer, by measuring the radioiodine uptake with a second dose of 4.5 mCi of [131I]sodium iodide. Calculations showed that the major etiology was probably therapeutic irradiation of the thyroid by the first dose.

Combined Modality Therapy↗
PubMed1984

Assimilation of Indian immigrant adolescents in British society.

Assimilation into British society was studied with first- and second-generation Indian immigrant adolescents and English boys and girls (N = 395, age range 14-16 years). They were administered a questionnaire designed by Danziger to monitor changes in their cultural perspectives, such as sex role specialization, autonomy in everyday life, and parents' perceived expectations. Analysis of variance revealed that no changes occurred among second-generation Indian girls, who enjoyed less autonomy in their daily lives than English girls and boys did. Second-generation Indian girls also perceived greater expectations from both parents to play a more responsible role in household activities. Few significant changes were found for Indian boys.

Acculturation↗
PubMed1983

Synthesis of thyroglobulin in thyroid carcinoma patients after radioiodine therapy.

Endogenously radioiodinated thyroglobulin (Tg) and the serum concentration of Tg have been measured in patients with metastatic thyroid carcinoma after therapeutic doses of radioiodine. Serial samples of blood were analyzed for both these parameters over a period of 10 to 22 days. The specific activity of Tg (cpm/ng) was calculated for each sample. Among the six patients studied, three showed constant specific activity. The specific activity of the other three fell, indicating the entering of newly synthesized Tg into the circulation. The respective amounts of Tg entering into the circulation in these three patients were 120, 852, and 20,935 ng/ml serum/day.

Carcinoma↗
PubMed1982

Disappearance rate of endogenously radioiodinated thyroglobulin and thyroxine after radioiodine treatment.

Endogenously radioiodinated thyroglobulin (tg) and thyroxine (T4), in the circulation following, therapeutic doses of radioiodine were studied in five patients with differentiated thyroid carcinoma. Radioactive serum was fractionated on a Sephadex G-200 and the various radioactive peaks thus obtained were analyzed for their biochemical and immunologic characteristics using precipitation with trichloroacetic acid (TCA) and antithyroglobulin antibody extraction with acidified n-butanol and electrophoresis on agar gel. The disappearance rates of endogenously labelled tg and T4 were 3.12 +/- 0.396 days and 10.14 +/- 1.81 days, respectively.

Adenocarcinoma↗