Biomedical subjects

R G Gheri

Publications and source records attributed to R G Gheri.

23 records · Page 2Linked to original sources

PubMed1983

Effects of thyroid replacement therapy on catecholamine plasma levels.

Plasma catecholamines (CA), total and free thyroid hormones (T4, FT4, T3, FT3) and thyrotropin (TSH) were measured before and during therapy in seven normotensive women with primary hypothyroidism lasting for more than 6 months. Twelve normal women matched for age were used as controls. In hypothyroid patients plasma norepinephrine (NE) was found increased in supine and upright position and plasma epinephrine (E) unchanged. After 30-60 days of therapy with dry thyroid extract, NE, T3, and FT3 levels were found in the normal range while T4 and FT4 levels, although raised, were still significantly lower than those of controls. These results seem to demonstrate that low doses of replacement therapy can restore NE levels to normal and therefore suggest that severe hypothyroidism alone is able to affect the sympathetic function.

Adult↗

PubMed1983

[Thyroid function in patients chronically treated with amiodarone].

The effects of Amiodarone (1000-1400 mg/week, for a period ranging from 3 to 24 months) on thyroid gland function were studied in 45 patients with heart disease, using a new method of free thyroid hormone assay. Forty-four untreated patients and 11 normal subjects were used as controls. In treated patients the prevalence of dysthyroidism was 22,2% (15,6% hypothyroidism and 6,6% hyperthyroidism); the onset of dysthyroidism ranged from 20 days to 2 years after the beginning of treatment. In control patients the prevalence of dysthyroidism was 4,4% (2,2% hypothyroidism and 2,2% hyperthyroidism). In patients with hypothyroidism (TSH greater than 7 microunits/ml) T4 levels were generally low, while T3, fT4 and fT3 levels were normal. In treated patients with hyperthyroidism (fT3 greater than 5,3 pg/ml and fT4 greater than 16 pg/ml) T4 values were high, while T3 concentrations were in the normal range. In Amiodarone-treated euthyroid patients, mean T4, fT4 and rT3 values were significantly (p less than 0,01) higher than those of control subjects; TSH levels were normal in all the groups studied. These data suggest that Amiodarone can exert both a direct effect on the thyroid gland and the peripheral metabolism of thyroid hormones. The action on the thyroid gland is suggested by the high prevalence of dysthyroidism in Amiodarone-treated patients and by the high levels of T4 and fT4 observed in patients who did not show dysthyroidism. The action on the peripheral hormonal metabolism seems to be proved by the high levels of rT3 and by the prolongation of QTc interval.

Aged↗

PubMed1981

Thyroxine and triiodothyronine levels in thyroid vein blood and in thyroid tissue of patients with autonomous adenomas.

Thyroxine (T4) and triiodothyronine (T3) concentrations were measured in peripheral and thyroid vein blood and in nodular and extranodular thyroid tissue from twenty-four patients with autonomous thyroid nodules (AFTN); fifteen of these patients showed clinical signs of hyperthyroidism and nine were euthyroid. Thirteen patients with solitary non-functioning thyroid adenomas who were clinically euthyroid, served as controls; samples of thyroid vein blood and normal thyroid tissue being obtained from the contralateral lobe. T4 (189.4 +/- 27.2 nmol/l) and T3 (7.05 +/- 2.03 nmol/l) concentrations were significantly higher in the thyroid vein blood of patients with AFTN compared with controls (T4 = 119 +/- 9.1 nmol/l, P less than 0.05; T3 = 2.3 +/- 0.21 nmol/l, P less than 0.01) whereas peripheral levels in the two groups were similar. The T3 concentrations (10.56 +/- 4.12 nmol/g wet tissue) in autonomously-functioning thyroid nodular tissue were significantly higher than those of extranodular (1.9 +/- 0.62 nmol/g wet tissue, P less than 0.01) and normal thyroid tissue (2.63 +/- 0.43 nmol/g wet tissue, P less than 0.05). The T4 levels were not different in the tissues examined. The concentrations of T4 and T3 in thyroid vein blood did not show any significant correlation with the hormone levels in thyroid tissue.

Adenoma↗

PubMedDate not supplied

A study on human adrenal secretion. Measurement of epinephrine, norepinephrine, dopamine and cortisol in peripheral and adrenal venous blood under surgical stress.

Epinephrine (E), norepinephrine (NE), dopamine (DA) and cortisol (F) were measured in samples drawn simultaneously by direct venepuncture from the brachial and the adrenal vein of 12 patients undergoing surgery for left kidney diseases. In 7 patients the influence of anesthesia on peripheral plasma levels was also assessed. Catecholamines were measured by a radioenzymatic assay and F by radioimmunoassay. Compared to basal values (mean +/- SE) (E: 53.6 +/- 6.2 pg/ml; NE: 209.4 +/- 24.4 pg/ml; DA: 24.5 +/- 3.3 pg/ml; F: 12.9 +/- 1.2 micrograms/dl) only NE peripheral levels were significantly modified by anesthesia (NE: 343.7 +/- 67.4 pg/ml p less than 0.05), whereas under surgery a significant increase in the peripheral levels was found for every substance measured (mean +/- SE) (E: 332.5 +/- 46.6 pg/ml p less than 0.001; NE: 633.6 +/- 114.2 pg/ml p less than 0.005; DA: 85.8 +/- 15.7 pg/ml p less than 0.005; F: 21.3 +/- 1.9 micrograms/dl p less than 0.01). Catecholamine and F levels in adrenal vein showed a high variability suggesting an intermittent secretion. In the adrenal venous blood E levels were, in the mean, 381 times higher, NE levels 45 times, DA levels 27 times and F levels 23 times higher than in peripheral blood. E, NE and DA concentrations in the adrenal vein were all significantly correlated to the others but not to cortisol, suggesting that the medulla secrets E, NE and DA in rather constant ratios and that the cortex and the medulla respond differently to surgical stress.

Adrenal Glands↗

PubMedDate not supplied

Clinical, biochemical and therapeutical aspects of amiodarone-induced hypothyroidism (AIH) in geriatric patients with cardiac arrhythmias.

The clinical features and the laboratory aspects of the amiodarone-induced hypothyroidism (AIH) in the elderly as well as the effects of amiodarone treatment in aged AIH people have not yet been well clarified. In the present paper, we evaluated 18 subjects of both sexes (7 females, 11 males), aged 65-83 years, affected by AIH, recruited in Central Tuscany, Italy. The patients were divided in two subsets on the basis of thyroid stimulating hormone (TSH) values: mild (TSH < 20 mU/l; Group A, n=11) and severe (TSH > 20 mU/l; Group B, n=7) hypothyroid patients. On the basis of clinical features, hypothyroidism was diagnosed only in two patients (out of Group B). Concerning the hormonal pattern, we found that free tetraiodothyronine (fT4) levels were significantly lower than the normal range only in Group B subjects; TSH and thyroglobulin were higher than normal in both groups; free triiodothyronine (fT3) were always in the normal range. Thyroid autoantibodies were found positive only in one patient out of Group A and in two patients out of Group B. In 5/18 patients T4 substitutive therapy was rapidly assigned, because of severe degree of hypothyroidism. In the remaining 13/18 patients, we evaluated the clinical behavior of AIH. After additional cardiac evaluation, amiodarone was withdrawn in 5/13 patients: during follow-up period (4-10 months) four patients became quickly euthyroid while one worsened. In 8/13 patients, amiodarone treatment had to be carried on; during follow-up (2-48 months), four patients remained mildly hypothyroid, while other four patients became severely hypothyroid. In conclusion, in amiodarone treated elderly people, diagnosis of hypothyroidism is reliable only on the basis of high values of TSH; clinical features and fT3 serum levels never enable diagnosis.

Aged↗