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Biomedical subjects

N Custro

Publications and source records attributed to N Custro.

8 recordsLinked to original sources
PubMed1992

Pituitary resistance to thyroid hormone action with preserved circadian rhythm of thyrotropin in a postmenopausal woman.

We assessed the 24-h behavior of circulating TSH and the dopaminergic control on TSH release in a postmenopausal woman, who had elevated levels of serum thyroid hormones and an inappropriately high concentration of serum TSH, indicating pituitary resistance to thyroid hormone action. The patient was found to have a daily profile of serum TSH similar to that of normal subjects, except for the persistently elevated 24 h levels, suggesting that alterations in thyroid hormone negative feedback control did not affect substantially circadian TSH rhythm. The acute administration of a dopamine antagonist drug (metoclopramide) resulted in a markedly elevated peak of serum TSH, similar both in the morning and in the evening. The chronic administration of a dopamine agonist drug (bromocriptine) reduced basal and TRH-stimulated TSH, restored circadian TSH variations to lower levels, and normalized other thyroid function tests. Although the metoclopramide test results confirmed the existence of an increased dopaminergic inhibitory tone in nonneoplastic inappropriate secretion of TSH, the outcome of bromocriptine treatment indicated that the dopaminergic control over TSH release was not enough in this case of PRTH.

Circadian Rhythm↗
PubMed1992

Alterations in circadian rhythm of serum thyrotropin in critically ill patients.

To evaluate the 24-h pattern of serum thyrotropin (TSH) in critically ill patients, we measured serum concentrations of TSH in blood samples collected every 2 h for 24 h from nine patients (six with malignancy, two with liver cirrhosis, one with chronic renal failure), who had subnormal levels of both triiodothyronine (T3) and thyroxine (T4), in the absence of history, symptoms or signs of thyroid disease. Analysis of the data, performed using a second-order inferential statistical methodology for rhythmometry (cosinor method), demonstrated that critically ill patients still had daily oscillations of serum TSH which significantly adapted to the function approximating the circadian rhythms (R2 = 74.3%). However, the mean level (mesor) in the rhythm of the patients was found to be significantly lower than that of healthy subjects (0.96 vs 2.18 mU/l); the amplitude of rhythmical daily variations also was lower in patients than in healthy subjects (0.23 vs 0.56 mU/l), even though the amplitude/mesor ratio was similar (23% vs 26%). Lastly, the highest level in the TSH rhythm of the patients was found to be in the late afternoon, in contrast to healthy subjects, who had a TSH surge after midnight. Although these alterations are consistent with the existence of a dysregulation at suprahypophyseal level in critically ill patients, it remains to be established whether the state of low T3 and T4 may be ascribed to anomalous circadian rhythm of TSH.

Adult↗
PubMedDate not supplied

Prospective study on thyroid function anomalies in severely ill patients.

Patients with severe non-thyroidal illness (NTI) often evidence concomitant anomalies in thyroid function (TF). In order to shed light on the implications of these anomalies and/or changes and disease course, we monitored TF changes in a selected cohort of 45 patients with serious NTI (21 with liver cirrhosis, 15 with renal failure and 9 with malignancy) from April 1985 to October 1989. TF test results on admission were as follows: all patients had normal thyroid stimulating hormone (TSH) levels; 16 patients had no TF abnormalities; 28 had decreased serum triiodothyronine (T3) and increased serum reverse triiodothyronine (rT3) levels, (8 of them had low serum free T3 values as well); 1 patient had subnormal level of both T3 and thyroxine (T4). Fifteen (53.5%) of the 28 subjects with initial low T3 sustained a subsequent decline in total and free serum T4 to subnormal levels; in 13 of these patients the drop occurred shortly before death. Patients in critical condition with below normal serum T4 also had decreased serum TSH concentrations: the so-called "low T3 and low T4 syndrome" might thus result from decreased TSH concentrations: due to failure of the usual feedback mechanism. Eighteen patients (40%) had died by the end of the study period. The mortality rate was 89% in patients with initial T3 level less than 0.40 nmol/L. This finding leads us to the hypothesis that initial low T3 levels in NTI patients are indicative of a poor prognosis.

Aged↗
PubMedDate not supplied

[Changes in blood levels of the pituitary-thyroid axis observed during therapy with protirelin ++ in hospitalized euthyroid patients with cerebrovascular disease].

The effects of a TRH-T (protireline tartrate) treatment at a dose of 2 mg/day for 3 weeks on the serum levels of the pituitary-thyroid axis hormones, have been studied in a randomized group of 10 elderly euthyroid hospitalized patients with cerebrovascular disease. At the end of the treatment an 8.3% mean increase of serum T3 level and a 12.5% mean increase of serum FT3 level (p less than 0.02 in both cases) have been observed. At the same time a 34% mean decrease of the basal TSH (p less than 0.05) and a 26% mean decrease of the delta-TSH after TRH-test (p less than 0.025) have been noted. However, the hormone concentrations changes never exceeded the normal values. In a randomized group of 9 hospitalized untreated patients with cerebrovascular disease used as controls (matched for age and sex), no significant changes of studied hormones have been recorded. In the treated patients, one week after the withdrawal of therapy serum levels of thyroid hormones and TSH went back to the levels observed before treatment. TRH-T seems to cause these modest hormone changes by decreasing the number of TRH receptors and the activity of TSH secreting cells. Nevertheless, the presence of the normal feedback in the pituitary-thyroid axis, allows a good tolerance to such a treatment.

Aged↗
PubMedDate not supplied

[Changes in the thyroid hormone picture that may be found in severely decompensated type II diabetics].

Thyroid hormone picture of 28 patients (15 males and 13 females), mean age 56.6 yr (range 45-65 yr), with seriously decompensated type II diabetes mellitus has been studied. In each patient the study was repeated after 3 months of treatment of diabetes. The patients showed significantly lower serum T3 levels and significantly higher serum rT3 levels (P less than 0.001), in comparison with a group of 16 normoglicemic subjects. After 3 months of strict control of diabetes T3 and FT3 significantly increased (P less than 0.01), whereas significant variations of rT3 were not found. Among the whole group of diabetics 5 patients had low levels of serum T4 (P less than 0.01 vs. controls), high levels of serum TSH (P less than 0.001 vs. controls) and an exaggerated responsiveness to exogenous TRH (P less than 0.001 vs. controls). After the 3 months of treatment these patients showed a significant decrease of rT3 (P less than 0.02) and of delta-TSH (P less than 0.01). In the whole group of diabetics significant statistical correlations between glycometabolic and thyroid parameters were not found. The study, on the whole, showed in patients with seriously decompensated type II diabetes, a hormone picture like the low-T3 syndrome, in some cases, however, pituitary TSH secretion suggested the existence of incipient failure of thyroid hormones. A connection between alterations in thyroid hormone picture and glycometabolic imbalance, even statistically labile, is however indicated by improvement of thyroid function when diabetes is carefully controlled.

Diabetes Mellitus, Type 2↗