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Biomedical subjects

K B Desai

Publications and source records attributed to K B Desai.

At least 19 recordsLinked to original sources
PubMed1994

Thyroid hormones in differentiated thyroid cancer.

In a study of 136 differentiated thyroid cancer patients referred for radioiodine therapy since January 1991, it was observed that 80 patients had metastatic disease. Of them, 51 had elevated levels of thyroglobulin (Tg), and of these 51 there were 15 patients who had functioning metastases with evidence of thyroid hormone synthesis by these metastases. All but 1 of these 15 cases with normal hormone levels in the circulation were follicular carcinomas with skeletal metastases. The response of these patients to radioiodine was poor. The group of patients with high Tg levels but low hormone synthesis and low circulating hormones responded better to radioiodine. Patients with low Tg levels and low hormone synthesis showed good response to radioiodine--especially patients with residual thyroid tissue after surgery and those with nodal disease.

Adenocarcinoma, Follicular↗
PubMed1993

Measurement of serum thyrotropin levels using sensitive immunoradiometricassays in patients with chronic renal failure: alterations suggesting an intact pituitary thyroid axis.

Serum thyroid stimulating hormone (TSH) levels were measured in 127 patients with varying grade of chronic renal failure (CRF). Sensitive immunoradiometricassays (IRMA) were used so that small changes in TSH levels if any, could be appreciated, and to see if such alterations exhibit some relationship with those in thyroid hormone levels. Mean serum TSH levels in the patient group of 2.33 microU/ml (0.07-7.3) was significantly higher in comparison to 1.73 microU/ml (0.25-4.6) in normal subjects (p < 0.001). However, they were not significantly different when measured by radioimmunoassay (RIA) as compared to normals. Serum triiodothyronine (T3), thyroxine (T4) and free triiodothyronine (FT3) levels of 72 +/- 32 ng/dl, 7.4 +/- 2.6 micrograms/dl and 2.9 +/- 0.9 pg/ml were significantly lower than in normal subjects, whereas serum free thyroxine (FT4) showed a slight though not significant elevation. When patients were divided in three subgroups according to the degree of renal insufficiency, TSH levels showed a gradual rise with corresponding depression in their T3, FT3 and T4 levels. In 19 patients who were on hemodialysis (HD) and subsequently received successful renal transplantation, most of the thyroid function parameters returned towards the normals with TSH undergoing significant depression from their pretransplant levels as well as from normal levels. The results indicated that a slight but significant elevation in TSH levels could be revealed by sensitive IRMA in patients with CRF. Rising TSH levels with increasing renal insufficiency and its inverse relationship with T3 and T4 levels suggest maintenance of pituitary thyroid axis.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1991

Total and free thyroid hormone levels in chronic renal failure.

The levels of serum total thyroxine (TT4), triiodothyronine (TT3), free T3, (FT3) free T4 (FT4) and thyrotropin (TSH) were measured in 127 clinically euthyroid patients with varying grades of chronic renal failure (CRF); and 97 healthy individuals. They were grouped as: Group I containing 93 patients on conservative management; Group II containing 34 patients on regular dialysis therapy; and Group III (normals). Group I patients showed significant decrease in TT3, TT4 and FT3 levels (p less than 0.001) as compared to Group III, whereas FT4 and TSH values in group I were not significantly altered. TT3, TT4 and FT3 levels reduced as the severity of renal damage increased. Variations in TT3, TT4, FT3, FT4 and TSH levels in Group II patients were similar to those in Group I, except for a decrease in TSH levels (p less than 0.05) as compared to normals. Several thyroid function tests are abnormal in CRF patients, however, finding of normal FT4 and TSH levels would indicate functional euthyroid status.

Humans↗
PubMed1991

Detection of autoantibodies against 3,5,3'-triiodothyronine in a hyperthyroid patient (a case report).

A 35-year-old female patient was evaluated for thyroid function and was found to be hyperthyroid clinically and by laboratory tests. During the course of treatment with neomercazole, she developed a bizarre picture with consistently low T3 levels irrespective of her clinical thyroid status and other laboratory tests like serum T4 and TSH levels. The serum of the patient when analysed for the presence of autoantibodies was positive for those against T3. The presence of T3 autoantibodies was confirmed by other laboratory techniques like assessment of blank values in radioimmunoassay, binding of T3-125I to isolated gamma globulin and starch gel electrophoresis. Autoantibodies were found to be present only against T3 and not against. T4 The affinity constant of T3 antibodies was 4 x 10(9) lit. mol-1 as determined by Scatchard plot analysis while total binding capacity was 23 x 10(-11) mol/L.

Adult↗
PubMed1991

Determination of free thyroxine in serum using column chromatography & radioimmunoassay.

A simple method for measurement of free thyroxine (FT4) levels in serum by adsorption chromatography and subsequent radioimmunoassay (RIA) is described. Assay sensitivity observed by this method was 1.2 pg/ml. Intra-assay variability was 11.2 per cent for FT4 concentrations of 7.9 pg/ml (n = 10), while interassay variability was 23.3, 9.7 and 12.9 per cent respectively for concentrations of 2.66, 12.06 and 23.96 pg/ml (n = 16). Serum FT4 concentration estimated by this method in 79 euthyroid patients was found to be 10.8 +/- 3.1 pg/ml. Values of FT4 obtained in hypothyroid and hyperthyroid patients were outside the normal range. FT4 values obtained by this method correlated well with the standard Liso-phase FT4 kit (r = 0.8) as well as free FT4 index (r = 0.93).

Chromatography↗
PubMed1989

Simultaneous production of antibodies against T3 and T4 in a single animal; their characteristics and usefulness in radioimmunoassay.

Simultaneous production of antibodies against triiodothyronine and thyroxine was attempted in a single rabbit by immunizing the animal with T3-albumin conjugate and T4-albumin conjugate at the same time. This resulted in the production of antibodies against both T3 and T4. The characteristics of each antibody were studied and the antiserum was used for determination of serum T3 and T4 concentrations by radioimmunoassay. The results were compared with those obtained with antibodies against T3 and T4 which were produced individually in different rabbits and were found to be more or less similar. From the results of the experiments, it appears that it is possible to make antibodies against T3 and T4 simultaneously in a single rabbit.

Animals↗
PubMed1988

Measurement of specific activity of radiolabelled antigens by a simple radioimmunoassay technique.

A simple radioimmunoassay (RIA) technique for measurement of specific activity of radiolabelled antigen is described. The technique involves setting up of a conventional RIA using multiple amounts of radiolabelled antigen as the unknown substance together with several RIA tubes containing the same amount of radiolabelled antigen with various known amounts of stable carrier. The known and unknown substances are equated at identical B/F ratio which would give the amounts of radiolabelled antigen. Counting the radioactivity in a counter with known efficiency gives its radioactive strength.

Radioimmunoassay↗
PubMed1988

Intra-articular injection for pain relief in patients awaiting hip replacement.

A double blind randomised trial was carried out to ascertain whether intra-articular injections of saline, bupivacaine or bupivacaine plus triamcinolone would be of value in the relief of hip pain suffered by patients awaiting total hip replacement for osteoarthritis. The majority of patients had good pain relief for 1 month but in general this was not maintained and some patients were much worse after the injection.

Aged↗
PubMed1987

Thyroid function and thyrotropin levels in rabbits immunized to produce antibodies against thyroid hormones.

Various parameters of thyroid function were studied in 27 rabbits, out of which 10 were immunized to produce antibodies against triiodothyronine (T3), 9 against thyroxine (T4) and 8 were normals. Estimations of T3, T4, Free T4 (FT4) and thyrotropin (TSH) in blood, qualitative and quantitative analysis of iodoamino acids in serum, protein bound iodine-131 (PB131I), butanol extractable iodine-125 (BE125I) and measurement of the disappearance rates of 125I-labelled T3 and T4 from plasma were done. In addition, glandular changes were also studied by measurement of 131I uptake, thyroid scanning and chromatographic analysis of hydrolysate of soluble iodoproteins. In T3 immunized animals, levels of T3 in serum increased by 38 to 125 times, levels of TSH also showed a significant rise (7.4 +/- 1.2 vs 28 +/- 9 ng/mL). Chromatographic analysis of iodoamino acids in serum as well as in the hydrolysate of the thyroid gland demonstrated a selective increase in synthesis of T3. Rate of disappearance of T3 from blood showed a significant decline. Thyroid glands in the immunized rabbits showed signs of hypertrophy and hyperplasia. Identical studies done in rabbits immunized to produce antibodies against T4 showed a similar pattern though of variable degree. Our studies indicate that the thyroid glands of the immunized rabbits undergo marked alterations resulting in selective increase in the synthesis and secretion of the particular thyroid hormone against which they were immunized. They do so under the influence of increased levels of TSH.

Amino Acids↗
PubMed1987

Increased sensitivity of triiodothyronine antibodies for radioimmunoassay after removal of endogenous antigen by simple laboratory procedures.

Conventionally produced antibodies against triiodothyronine (T3) are known to possess high amounts of endogenously produced T3 associated with them. We felt that such antibodies would work better for T3 radioimmunoassay (RIA) after prior removal of the antigen. With this in view, we attempted dissociation and subsequent removal of T3 from antisera by two different methods, viz. dialysis and alcohol extraction. It was possible to remove T3 to an extent of 77% by alcohol extraction and 60% by dialysis. Resultant antisera fail to demonstrate any increase in the titre. However, when standard curves were generated using these antisera, the assays became more sensitive and it was possible to detect T3 in concentrations as low as 6.25 pg. The affinity constants of these antisera calculated from the respective Scatchard plots were found to have increased after both dialysis treatment was well as alcohol extraction. This was thought to be due to rendering some of the high affinity binding sites on the antibodies free of antigen after treatment. Serum T3 levels were measured in 68 patients with various thyroid status using both treated as well as untreated antiserum. The difference between the average values of serum T3 concentration estimated using various antisera before and after the treatment was not statistically significant. Our results suggested that a simple procedure like stripping of antigen from antibodies could be of help for acquiring high affinity and high sensitivity antibodies for this purpose.

Antibodies↗