Despite many previous studies on the association between hyperthyroidism and the hyperadrenergic state, controversies still exist. Detrended fluctuation analysis (DFA) is a well recognizedmethod in the nonlinear analysis of heart rate variability (HRV), and it has physiological significance related to the autonomic nervous system. In particular, an increased short-termscaling exponentα1 calcula...

BACKGROUND The prevalence of concurrent disease in hyperthyroid cats is unknown. OBJECTIVES To identify the prevalence of concurrent intra-abdominal disease using abdominal ultrasound examination (AUS) in hyperthyroid cats referred for radioactive iodine treatment (RIT) and to determine whether the requirement for pretreatment AUS is justified. ANIMALS Five hundred and thirty-four client-ow...

Hyperthyroidism in rats is associated with increased oxidative stress. These animals also show abnormal renal hemodynamics and an attenuated pressure-diuresis-natriuresis (PDN) response. We analyzed the role of oxidative stress as a mediator of these alterations by examining acute effects of tempol, a superoxide dismutase mimetic. The effects of increasing bolus doses of tempol (25-150 micromol...

BACKGROUND There are limited data about the influence of hypothyroidism and hyperthyroidism on the connective tissue component and smooth muscle cells of the thoracic aorta. The aim was to study the histological changes of the wall of the thoracic aorta in the hypothyroid and hyperthyroid rats. Morphometric measurements were also done. MATERIALS AND METHODS Thirty adult rats were used. They w...

The aim of the present study was to determine the changes in phospholamban protein levels and their regulatory effect on sarcoplasmic reticulum (SR) Ca2+ uptake and left ventricular function in hypothyroid and hyperthyroid rat hearts. Hypothyroidism was associated with decreases in basal left ventricular function (+dP/dt and -dP/dt), whereas in hyperthyroidism these parameters were elevated com...

STUDY OBJECTIVE The mechanism of exercise intolerance in hyperthyroidism has not been fully elucidated. This study was undertaken to determine if hyperthyroidism reduced the efficiency of sub-maximal exercise. STUDY DESIGN We measured cardiorespiratory variables up to the anaerobic threshold (AT) during ramp-loading cycle ergometry in 12 patients (New York Heart Association functional class I...

The occurrence of thyroid malignancy is considered a rare event in hyperthyroid patients. With the aim of assessing the clinical relevance of this association, we have analyzed the incidence of thyroid cancer in hyperthyroid patients treated by surgery. The incidence of thyroid cancer was retrospectively evaluated in 202 hyperthyroid patients who underwent thyroidectomy during a twenty-year per...

AIMS Disturbed levels of thyroid hormones are associated with neuropsychiatric disorders, including memory impairments. The aim of this study was to evaluate effects of mild induced thyrotoxicosis on working memory and its neural correlates. METHODS Twenty-nine healthy, male subjects with normal thyroid state participated in the study. Functional MRI was acquired during a working memory task ...

BACKGROUND Evidence indicates that cardiac hypothyroidism may contribute to heart failure progression. It is also known that heart failure is associated with an increased risk of atrial fibrillation (AF). Although it is established that hyperthyroidism increases AF incidence, the effect of hypothyroidism on AF is unclear. This study investigated the effects of different thyroid hormone levels, ...

introduction: hyperthyroidism is a relatively common disorder caused by different etiologies. graves’ disease, and toxic-nodular goiter (plummer’s disease) are among the most common causes. treatment with radioiodine is considered to be the treatment of choice in many of the patients. higher biological half-life of ¹³¹i in hyperthyroid patients as compared with patients with differentiated thyr...