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Biomedical subjects

G Hennemann

Publications and source records attributed to G Hennemann.

At least 145 records · Page 8Linked to original sources
PubMed1976

Binding of L-triiodothyronine to isolated rat liver and kidney nuclei under various circumstances.

Triiodothyronine (T3) is specifically bound by nuclei from rat liver and kidney. Binding of T3 at 37 degrees C reaches its maximum at 30 min. In the presence of EDTA (to remove Mg2+) T3 binds to a class of binding sites with an estimated equilibrium association constant (Ka) of 3.3 x 10(10) M(-1) and a maximal binding capacity (MBC) of 3.8 fmol T3/100 mug DNA. In the presence of MgCl2 T3 binds to a second class of binding sites with an estimated Ka of 4.8 x 10(8) M(-1) and a MBC of 123 fmol/100 mug DNA. Among the analogues tested, binding - relative to T3 - of D-T3, triiodothyoacetic acid and desamino-T3 is the same for both classes of binding sites, but relative affinity of thyroxine, D-T4, tetraiodothyroacetic acid and desamino-T4 is 2.5 to 6 times higher for the second class of binding sites than for the first class. The presence of a cytosol binding protein is not a prerequisite for binding of T3 to the nucleus.

Animals↗
PubMed1976

Specific binding sites for L-triiodothyronine in rat liver and kidney cytosol.

Binding of 125I-labelled triiodothyronine (T3) to rat liver and kidney cytosol was examined. In both organs a very similar binding protein was detected. The apparent equilibrium association constants amounted to 4.8 X 10(7) M-1 for the liver protein and to 1.8 X 10(7) M-1 for the kidney protein. In the two organs a high capacity for T3 binding was observed: maximal binding capacities of respectively 4.3 and 33.2 pmol per mg total cytosol protein. Displacement studies using thyroid hormone analogues showed that the binding exhibited similar specificity.

Animals↗
PubMed1975

Serum thyrotrophin concentration: an unreliable test for detection of early hypothyroidism after thyroidectomy.

Three groups of patients who had undergone subtotal thyroidectomy for Graves's disease, toxic multinodular goitre, or euthyroid multinodular goitre 12 to 15 years before and in whom a normal serum thyroxine (T-4) level was found were each divided into two subgroups on the basis of a normal or a raised serum thyrotrophin concentration. There was no difference in mean serum T-4 concentration between patients with normal and those with raised serum thyrotrophin concentrations, and the values were similar to the mean T-4 values of the normal population. The mean serum triiodothyronine values of all groups were higher than normal, but the mean values of the groups with a normal and a raised serum thyrotrophin were similar. After thyroidectomy a mildly raised serum thyrotrophin does not in itself indicate the presence of hypothyroidism.

Humans↗
PubMed1975

A radioimmunoassay for the measurement of pyroglutamyl-histidyl-proline, a proposed thyrotropin releasing hormone metabolite.

A highly specific radioimmunoassay for the measurement of pGlu-His-Pro-OH (TRH-OH), a compound proposed to be a metabolite of pGlu-His-Pro-NH2 (TRH) has been developed. Using this assay experiments have been performed to study the inactivation of TRH and TRH-OH by serum. The results show that TRH-OH is inactivated in a fashion resembling the inactivation of TRH as has been described by others. Support for the deamidation mechanism as the main pathway for TRH degradation could not be achieved.

Animals↗
PubMed1975

Dissociation of serum LATS activity and hyperfunction and autonomy of the thyroid gland in Graves' disease.

LATS was measured with the double isotope technique in IgG serum concentrates of 23 patients with Graves' disease before treatment and of 18 patients during treatment with carbimazole and triiodothyronine. LATS activity was present in 18 out of 23 patients before treatment (78%). When the second measurement was taken into account the incidence did increase to 95%. No difference could be found in the mean values of total thyroxine, thyroid 131-I uptake and thyroid weight of the group of LATS positive and LATS negative patients before treatment. Also no relation could be established between LATS activity and suppressibility of thyroid 131-I uptake during treatment. It was found that LATS positive patients who suppress during therapy have lower initial LATS blood levels than LATS positive patients who remain unsuppressed. It is concluded that it is more likely that LATS is a "marker" of Graves' disease rather than the cause of the hyperthyroidism.

Adult↗
PubMed1974

Hypothyroidism after thyroidectomy for Graves's disease: a search for an explanation.

Out of 38 patients who had undergone subtotal thyroidectomy for Graves's disease seven to 20 years previously 15 developed hypothyroidism. In these 15 patients autoantibodies against thyroid cytoplasm were significantly more frequent than in the 23 euthyroid patients, though there was no difference in the prevalence of autoantibodies against thyroglobulin. Histological examination of the thyroid tissue removed at operation showed that significantly more plasma cells and lymphoid follicles with germinal centres were present in patients who subsequently developed hypothyroidism than in those who remained euthyroid. No differences in the amount of lymphocytic infiltration were seen in hypothyroid and euthyroid patients.The results suggest that B lymphocytes play a part in the development of postoperative hypothyroidism in Graves's disease. It is proposed that Graves's disease and Hashimoto's disease are different aspects of the same basic autoimmune process.

Autoantibodies↗