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Biomedical subjects

R D Ganatra

Publications and source records attributed to R D Ganatra.

At least 37 records · Page 2Linked to original sources

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↗

Cost-effectiveness of screening for hypo- and hyperthyroidism in India.

The development of relatively inexpensive radioimmunoassay techniques opens new possibilities for widespread screening for hypo- and hyperthyroidism in developing regions where iodine deficiency is great. From component cost analysis, it appears that radioimmunoassays of thyroid hormones can be performed in India for as little as 2.4 rupees (29 cents) per test. Cost-effectiveness analysis indicates that screening for hypothyroidism in iodine-deficient areas in India is, of alternative detection strategies, the most cost-effective: Cases are found at an average cost of 40 rupees ($4.80) per case. Cost breakdowns and considerations of convenience and acceptability indicate that filter paper methods may soon be preferred to whole-blood assays, especially for screening. Cost-effectiveness findings for these screening strategies and for reasonable modifications of them should be compared with the estimated cost-effectiveness of iodine supplementation in determining optimal health policy toward subclinical thyroid disease.

Cost-Benefit Analysis↗

Serum thyroglobulin differentiated thyroid carcinoma: histological and metastatic classification.

Serum thyroglobulin (tg) levels were measured in 112 patients with proved differentiated thyroid carcinoma (6 pre-operative, 32 post-operative and 74 in whom thyroidectomy was followed by radioiodine treatment). The tg levels were within the normal range in patients who had a residual mass in the neck region after surgery and who were in remission. The patients with metastases showed a wide range (undetectable to microgram quantities) of tg in circulation. The analysis of serum tg with respect to histology showed that the follicular variety of carcinoma tends to show higher tg in serum than the papillary type. Metastatic involvement of bone was associated with much higher serum tg levels than other sites such as lung and lymph node. Thirteen patients with bone metastases of non-thyroidal primary origin had tg levels within the normal range. Serum tg estimation is useful in excluding thyroid as a primary site in patients with bone metastases of unknown primary origin.

Adult↗

Hepatobiliary kinetics of 113mIn-phenolphthalexon.

Phenolphthalexon, a compound with iminodiacetic acid as a functional group, has been labelled with 113mIn to high chemical purity and its usefulness in studies of biliary excretion patency has been studied. Organ distribution of 113mInphenolphthalexon in mice was characterized by high liver uptake (50.8% of the administered dose after 5 min) and rapid clearance through the gall bladder. An animal model for studying obstruction of biliary excretion has been developed. Data on the kinetics of the radiopharmaceutical were obtained by collecting in-vivo data through an on-line computer.

Animals↗

Pitfalls in the lateral imaging of the thyroid with pinhole collimators.

Imaging of the thyroid gland with pinhole collimators in the lateral projection is associated with the problem of count rate contribution from the contralateral lobe. In a series of experiments conducted using a thyroid-simulating phantom, the contribution of this nature was calculated. Radioisotopes of different energies such as 99mTc and 131I were used to see the effect of energy on this contribution. It was observed that the count rate contribution from the contralateral lobe to the lobe proximal to the collimator can be as high as 70% at a distance of 6 cm from the collimator. At distances more than 6 cm these contributions from the contralateral lobe are much more than this.

Iodine Radioisotopes↗

Scan appearances in hydatid cysts of the liver: analysis of 55 cases.

Liver scans done at our Centre between 1964 and 1977 were analyzed with reference to hydatid cysts in liver. Among the approximately 7200 patients analyzed, there were 55 suspected to have hydatid cysts. The criteria adopted in screening the patients for hydatid cysts were based upon clinical findings and liver scan findings. The cases were analyzed with respect to their histologic findings, locations of cold areas in the liver, and correlation with Casoni's test. We found that 1) the cystic involvement was most often in the right lobe of the liver; 2) Casoni's test does not rule out or establish the presence of hydatidosis; 3) radioisotopic vascular studies done in some cases contributed to the diagnosis; 4) although a positive liver scan does not indicate the cause of the disease, the scans showing large and totally photon-deficient cold areas along with good general condition of the patients help in the diagnosis of hydatid cysts in the liver.

Colloids↗

Modifications in biphasic liquid-scintillation vial system for radiometry.

Several modifications of the biphasic liquid-scintillation vial system for radiometry have been tried in order to improve the counting efficiency. The biphasic system consisted of an inner sterile vial containing medium and substrate, and an outer liquid-scintillation vial lined on the inside with filter paper impregnated with scintillation fluors and alkali. The system gave an overall counting efficiency of 14.6%. Substitution of methanolic NaOH for impregnation of the paper raised the counting efficiency to 29.1%. This could be further enhanced to 33.8% by lining only half of the outer vial with filter paper, thereby allowing improved optical transmission of scintillation light. Increasing the amount of fluor did not change the efficiency significantly. A complete interchange in the system, whereby half of the inner vial was lined with filter paper and was otherwise empty, while the outer vial contained the medium and substrate, gave the highest efficiency (36.9%). This also allowed the use of larger amounts of medium and the inoculum.

Carbon Dioxide↗

Radiorespirometric testing of antibiotic sensitivity in urinary tract infections: concise communication.

A radiometric method, based on inhibition of 14CO2 release from bacterial metabolism of C-14-labeled glucose, was applied to test the susceptibility of urinary organisms to antibiotics. The testing was also carried out by the routine disc diffusion method after isolation of the organisms. Results of susceptibility to antibiotics could be obtained within 2 to 4 hr by the radiometric technique, compared with the 48 hr required for the disc method.

Anti-Infective Agents, Urinary↗

Studies on Tc-99m-labeled liver ferritin: hepatobiliary behavior in rats: concise communication.

Ferritin was isolated from the livers of iron-loaded rats and labeled with Tc-99m. The radionuclide was found to be firmly bound to ferritin and essentially free of colloids. When injected into rats, about 65% of administered dose was found to be concentrated in the liver within 30 min. The blood activity declined rapidly. Liver activity appeared to be excreted slowly through the hepatobiliary route, through there was 5 to 9% constant excretion through the kidneys. The results suggest that this labeled protein may prove useful as a hepatobiliary radiopharmaceutical.

Animals↗