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Biomedical subjects

Tina Zimmermann-Belsing

Publications and source records attributed to Tina Zimmermann-Belsing.

4 recordsLinked to original sources

Thyrotropin-releasing hormone stimulation test in patients with pituitary pathology.

OBJECTIVES: To evaluate the value of the thyrotropin-releasing hormone (TRH) stimulation test in the diagnostic work-up of the thyroid function in patients with pituitary pathology. METHODS: To compare the thyrotropin (TSH) response and the absolute and fold changes after TRH administration in 35 patients with pituitary pathology and 26 normal subjects. RESULTS: Nine of the patients and 2 of the normal subjects had a pathological response. No difference in the thyrotropic response to TRH was found either for the actual values, or for the absolute or fold changes of TSH between the groups. CONCLUSION: The role of the TRH test in the evaluation of thyroid function in patients with pituitary pathology is modest. The best variables for evaluation of the presence of central hypothyroidism are still a free thyroxine estimate combined with an inappropriately low TSH.

Adolescent↗

Ultrasonically measured horizontal eye muscle thickness in thyroid associated orbitopathy: cross-sectional and longitudinal aspects in a Danish series.

PURPOSE: To analyse horizontal extraocular muscle findings by ultrasound and exophthalmometry in a tertiary endocrinology centre series of patients with thyroid associated orbitopathy (TAO). METHODS: The 90 thyroid patients included underwent ultrasonic measurement of horizontal eye muscle thickness by a B-scan based technique carried out in addition to their general ophthalmic evaluation. As an indicator of mainly advanced TAO, longterm prednisone or cyclosporine A was given to many of the patients, and drug-resistant visual loss indicated decompression surgery in four of the 90 patients. Thirty-four patients underwent repeated muscle recordings over 15-49 months; this allowed for cross-sectional analysis and the outlining of longitudinal trends. RESULTS AND CONCLUSIONS: (A) Although marginally overlapping, all four muscle groups were significantly thicker in the study group than in normal control subjects. The mean of the sum of all four muscles was 16.8 mm (range 13.6-21.7 mm) in the control group versus 22.6 mm (range 15.5-36.4 mm) in the thyroid group. (B) Using the clinical NOSPECS grading, more advanced eye involvement was found to generally result in a higher exophthalmometric measurement of protrusion and eye muscle thickness. However, slender rectus muscles and/or normal exophthalmometric values might occur even in advanced orbitopathy. (C) Over a period of 2-4 years, only a few of 34 patients with satisfactory serial ultrasonic measurements returned to their premorbid ophthalmic status. Typically, the extraocular muscles kept their abnormal size after having become clinically quiescent (fibrotic). (D) We found no safe indication regarding disease stage, active or late, from the ultrasonic appearance of the muscle tissue. (E) Discrepancies between various normative eye muscle studies are discussed with regard to computer tomography and magnetic resonance imaging.

Adolescent↗

Circulating leptin and thyroid dysfunction.

The identification and sequencing of the ob gene and its product, leptin, in 1994 opened new insights in the study of the mechanisms controlling body weight and led to a surge of research activity. Since its discovery, leptin has been the subject of an enormous amount of work especially within the fields of nutrition, metabolism and endocrinology. Leptin is accepted as an adipose signal, and even though the underlying mechanisms are not fully clarified, leptin, in addition to the thyroid hormones, is believed to be involved in regulation during the switch from the fed to the starved state. It is not clear whether leptin and the melanocortin pathways interact with the thyroid axis under physiological conditions other than during starvation or in response to severe illness, both states in which the hypothalamo-pituitary-thyroid axis may be severely suppressed. In addition to the suggested central relationship between leptin and thyroid hormones, there might also be a peripheral relationship although this effect is not clear. Both thyroid hormones and leptin might be involved in the adaptive thermogenesis through mitochondrial uncoupling proteins and heat production because both thyroxine and triiodothyronine are involved in the starvation-induced decrease in thermogenesis. Both rodent and human studies of leptin have failed to show any consistent relationship between thyroid function and serum leptin concentrations. However, leptin might have an important role in thyroid pathophysiology due to thyroid hormone involvement in thermogenesis and regulation of uncoupling proteins. In this review, we have focused on leptin in relation to thyroid pathophysiology.

Animals↗