Biomedical subjects

R Cech

Publications and source records attributed to R Cech.

3 recordsLinked to original sources

PubMed1997

Normal thyroxine and elevated thyrotropin concentrations: evolving hypothyroidism or persistent euthyroidism with reset thyrostat.

BACKGROUND: The natural course in subjects manifesting normal serum thyroxine (T4), and triiodothyronine (T3), with an elevated thyrotropin (TSH) level demonstrated two distinct outcomes, one progressing to well defined hypothyroidism as expressed by onset of subnormal T4, T3 and a further rise in TSH and the other remaining in the same state. However, thyroid hormone concentrations at the time of diagnosis fail to distinguish between the two groups. Therefore, we examined the influence of alteration in circulating TSH levels on thyroid gland function at the time of diagnosis in subjects with this syndrome to assess the role of pituitary thyroid axis in these different outcomes. METHODS: 24 hour 131I thyroidal uptake was determined in 14 men and 3 women manifesting normal T4, T3 and elevated TSH prior to and again after 1) subcutaneous administration of bovine TSH, 10 units daily for 3 days and 2) daily oral administration of L-triiodothyronine 75 micrograms for 7 days in a randomized sequence at interval of 4 weeks. Subjects were then followed for up to 16 years to assess the natural course. RESULTS: Basal 24 hour 131I uptake values were within the normal range (10-35%) in all subjects and increased on TSH administration and declined following LT3 administration. However, in eight subjects, these responses were markedly lower (< 20%) when compared with the minimum change (50%) noted in normal volunteers. These subjects progressed to manifest hypothyroidism requiring LT4 therapy within two years as reflected by a progressive decrease to subnormal T4 levels with a further rise in serum TSH. The remaining nine subjects, demonstrated normal responses (> 50%) and only one of these became hypothyroid during the follow-up period of 16 years. CONCLUSION: All subjects with normal T4 and T3 with elevated TSH do not manifest "subclinical or evolving hypothyroidism". Two distinct populations seem to exist, one with inhibited pituitary thyroid axis progressing to hypothyroidism or true "subclinical hypothyroidism" at the time of diagnosis and the other with normal pituitary thyroid axis, a state of euthyroidism with "reset thyrostat" at a higher TSH concentration, a state probably persisting for their remaining life span.

Adult↗

PubMed1994

Therapeutic 131I dose in hyperthyroidism: role of pretreatment with thionamide.

Radioiodine therapy has become a cornerstone of treatment of hyperthyroidism. However, the timing of its administration varies between 1) the time of initial diagnosis with concurrent therapy with beta adrenergic blocking drugs or 2) following induction of euthyroidism with thioamide, Propylthiouracil or Methimazole. This study assessed 24-HR 131I uptake values and the thyroid scan in 24 subjects with hyperthyroidism at the time of diagnosis and again after attaining the euthyroid state with Propylthiouracil or Methimazole. Propylthiouracil of Methimazole was withdrawn seven days prior to the second 24-HR 131I uptake and scan. In all subjects, as a group, 24-HR 131I uptake increased following antithyroid therapy as compared to the time of initial of diagnosis [76 + 5% Vs. 54 + 4%; p < 0.01]. The thyroid gland size decreased in nine of twenty-four subjects, but remained unchanged in the remaining subjects. Since 24-HR 131I uptake and the gland size are the major factors influencing the therapeutic radioiodine dosage, it is possible that initial therapy with thioamide drugs may reduce the therapeutic dose of 131I in subjects with hyperthyroidism belonging to both groups, i.e., Graves' disease and Multinodular toxic goiter by inducing a rise in 24-HR 131I uptake. Furthermore, the shrinkage of thyroid glands may further decrease the radioiodine dosage in patients with Graves' disease.

Adult↗

PubMed1987

Joint report of the Third International Workshop of Canine Immunogenetics. II. Analysis of the serological typing of cells.

Using a standardized microlymphocytotoxicity assay, seven international laboratories evaluated 144 anti-dog lymphocyte antigen (DLA) sera in 319 mixed breed and 152 Beagle dogs. The workshop confirmed the serological definitions for DLA-A2, A3, A9; DLA-B4, B5, B6, B13; DLA-C11(Cwl); and C12(Cw2). Two new specificities were assigned to the DLA-A locus (Aw14 and Aw15) in only the mixed breed dogs. A third specificity (Cw3), was assigned to the DLA-C locus. The antigen and gene frequencies of these alleles differed between the two groups of dogs, but the frequencies of the "blank" were similar in both groups. Future international collaborations will be necessary to definite more completely the polymorphisms of the major histocompatibility complex (MHC) of the dog. Those efforts will benefit from the standard serological test established in this workshop.

Alleles↗