Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The importance of thyroid hormone receptors for isometric force, endurance and content of specific muscle enzymes was studied in isolated slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles in mice deficient in all known subtypes of thyroid hormone receptors (i.e. TR alpha1, beta1, beta2 and beta3). The weights of soleus and EDL muscles were lower in TR-deficient (TRalpha1-/-beta-/-) mice than in wild-type controls. The force per cross-sectional area was not significantly different between TRalpha1-/-beta-/- and wild-type muscles. Soleus muscles of TRalpha1-/-beta-/- mice showed increased contraction and relaxation times and the force-frequency relationship was shifted to the left. Soleus muscles of TRalpha1-/-beta-/- mice were more fatigue resistant than wild-type controls. Protein analysis of TRalpha1-/-beta-/- soleus muscles showed a marked increase in expression of the slow isoform of the sarcoplasmic reticulum Ca2+ pump (SERCa2), whilst expression of the fast type (SERCa1) was decreased. There was also a major decrease in the alpha2-subunit of the Na+-K+ pump in TRalpha1-/-beta-/- soleus muscles. EDL muscles from TRalpha1-/-beta-/- and wild-type mice showed no significant difference in contraction and relaxation times, fatigue resistance and protein expression. In conclusion, the present data show changes in contractile characteristics of skeletal muscles of TRalpha1-/-beta-/- mice similar to those seen in hypothyroidism. We have previously shown that muscles of mice deficient in TRalpha1 or TRbeta display modest changes in muscle function. Thus, in skeletal muscle there seems to be functional overlap between TRalpha1 and TRbeta, so that the lack of one of the receptors to some extent can be compensated for by the presence of the other.
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PMID:Isometric force and endurance in skeletal muscle of mice devoid of all known thyroid hormone receptors. 1256 61

Primary hypothyroidism is a chronic and insidious disease caused by failure of thyroid hormone production. We observed a 38-year-old woman admitted to our hospital due to progressive proximal weakness, muscle pain and fatigue during mild exercise. Laboratory tests showed features of rhabdomyolysis and hypothyroidism. After examination of the thyroid, we reached a diagnosis of Hashimoto's thyroiditis and hypothyroid myopathy. Hypothyroidism should be considered as a differential diagnosis of creatine kinase elevation; actually, neuromuscular symptoms and signs occur in most newly diagnosed patients with thyroid diseases. Hypothyroidism presenting as muscle stiffness and pseudohypertrophy is called 'Hoffman's syndrome'.
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PMID:Hoffman's syndrome: muscle stiffness, pseudohypertrophy and hypothyroidism. 1258 16

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are chronic cholestatic liver diseases that affect 0.5 to 40 per 100,000 and 1 to 6 per 100,000 Americans, respectively. Prompt recognition and management of the clinical manifestations of these diseases is essential for the patients' well-being and ultimate outcome. Ursodeoxycholic acid (UDCA), 13 to 15 mg/kg per day, is the standard therapy for PBC and should be offered to every patient. It has been shown to slow progression of the disease and prevent the need for liver transplantation, which is the last recourse for patients with end-stage disease. However, there is no effective therapy for PSC yet. Patients are managed symptomatically, with surgical or endoscopic interventions as needed in cases of significant biliary obstruction. Complications of chronic cholestasis are seen in both PBC and PSC, with pruritus and fatigue being the most common complaints. The first choice for the treatment of pruritus is still cholestyramine, starting at 4 g/d. The pathogenesis of fatigue is poorly understood in this population; unrecognized hypothyroidism should be excluded. The use of antidepressants is currently under evaluation, but there is no specific therapy for fatigue as of yet. For prevention of severe osteoporosis, we recommend supplementation with 800 IU vitamin D and 1500 mg calcium/d. In patients with PBC and established osteoporosis, the use of alendronate and vitamin K appears to cause an increase in bone mineral density. Further studies are necessary before either of these drugs is routinely recommended. Finally, fat-soluble vitamin deficiencies are noted with more advanced disease. We recommend that serum levels be checked in high-risk patients, and that vitamins are replaced as appropriate with water-soluble supplements. However, other causes of malabsorption must be ruled out, including pancreatic insufficiency and celiac sprue.
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PMID:Treatment Options for Primary Biliary Cirrhosis and Primary Sclerosing Cholangitis. 1262 68

A 46-year-old woman with clinical diagnosis of Riedel's thyroiditis was admitted to our Department, presenting with dyspnea, dysphagia, fatigue, and hoarseness. Previously, she had been diagnosed with Hashimoto's thyroiditis and hypothyroidism. The disease had a progressive course and had lasted for a year before the definitive diagnosis of Riedel's thyroiditis was confirmed and treated with methylprednisolone, 12 mg daily, without success. We started therapy with tamoxifen, 10 mg twice a day, together with methylprednisolone, 16 mg daily, and L-thyroxin substitution therapy. The follow-up lasted for one year. Treatment with tamoxifen led to a significant subjective improvement and objective changes, confirmed by regular clinical examinations, ultrasonography, and computed tomography of the neck. After 8 months of therapy, the patient had no compression symptoms and goiter decreased in estimated weight from 105 g to 63 g according to ultrasound measurements. The patient underwent partial thyroidectomy at 10 months after diagnosis of Riedel's thyroiditis. Histopathology confirmed the diagnosis of Riedel's thyroiditis. Our report indicates that tamoxifen can be a valuable drug therapy in the treatment of Riedel's thyroiditis.
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PMID:Riedel's thyroiditis treated with tamoxifen. 1269 18

Hypothyroidism with thyroglobulin antibodies during corticoid replacement in a 54-year-old man with isolated ACTH deficiency. HISTORY AND ADMISSION FINDINGS: A 54-year-old previously healthy man was admitted because of fatigue, tiredness, diarrhoea and weight loss for the last 3 years. Physical examination revealed dry but normally pigmented skin and markedly reduced Achilles reflex bilaterally. INVESTIGATIONS: Erythrocyte sedimentation rate was slightly elevated at 32 mm/h, C-reactive protein was normal. Both haemoglobin (12.4 mg/dl) and the corpuscular indices were normal, as were serum electrolytes, and sodium bicarbonate. But basal levels of thyroid stimulating hormone (TSH, 8.5 mU/ml) was markedly elevated, while free peripheral triiodothyronine (3.2pg/ml) was normal and free thyroxine (fT4) at 0.7 ng/d was slightly reduced. Thyroid ultrasound was normal. Test for antinuclear antibodies was slightly positive, but double-strand DNA was not demonstrated. Antithyroglobulin antibodies were slightly raised to 1012 IU/ml (normal <350). The basic level of ACTH was repeatedly below detection, as were plasma cortisol and cortisol excretion in 24-hour urine. Nuclear magnetic imaging was normal. Failure to stimulate corticol synthesis in the short ACTH test and by CRH indicated an isolated ACTH deficiency at the level of the anterior pituitary, while other hypophyseal functions were unaffected. TREATMENT AND COURSE: The patient"s condition rapidly improved on replacement with hydrocortisone, 30 mg/d, and thyroxine, 100 mg/d. No thyroglobulin antibodies or antinuclear antibodies were demonstrable after 6 months. Thyroxine was discontinued after 15 months. Frequent monitoring of thyroid function over the next 2 years always indicated a euthyroid state. CONCLUSION: Subnormal concentration of peripheral thyroid hormone combined with elevated TSH levels can, in the presence of hypercorticolism, be due to reversible abnormal thyroid function.
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PMID:[Hypothyreoidism with thyroglobulin antibodies during corticoid replacement in a 54-year-old man with isolated ACTH deficiency] 1275 Oct 16

Subclinical hypothyroidism is associated with aspecific complaints such as tiredness, cognitive and depressive complaints, subtle disturbances in lipid values, an increased risk of cardiovascular disease, ovulatory dysfunction and a negative effect on foetal psychomotor development and pregnancy outcome. Subclinical hyperthyroidism is associated with atrial fibrillation, osteoporosis and dementia. Not enough prospective randomised studies with hard outcomes are available to provide evidence-based general recommendations. Therefore, the decision as to whether or not a patient should be treated needs to be made on an individual basis. For subclinical hypothyroidism it is advisable to consider treatment in the case of positive thyroid peroxidase antibody tests, a TSH concentration higher than 10 mU/l, the presence of one or more risk factors for cardiovascular disease, infertility on the basis of ovulatory dysfunction, and pregnancy. In the case of complaints of tiredness and certainly in the case of depression or cognitive dysfunction, a 3-month trial treatment can be considered. This leads to a decrease of the complaints in about 25% of cases. As negative effects are associated with the treatment, we advise an expectant approach in all other cases with a yearly monitoring of the TSH concentration. For subclinical hyperthyroidism it is advisable to consider treatment in the case of a nodular goitre, and especially in the case of atrial fibrillations. If subclinical hyperthyroidism persists in the absence of nodular thyroid disease, an expectant approach appears to be justified.
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PMID:[Subclinical functional disorders of the thyroid gland]. 1284 32

Often patients in whom there is little to suggest myxedema or cretinism have subclinical hypothyroidism. Once the condition is suspected, it can be diagnosed by determination of protein-bound iodine and, if the PBI is low, by response to therapy with thyroid hormone. Patients in the following categories should have protein-bound iodine determination: Those having (1) a history of previous treatment for hypothyroidism; (2) suboptimal development in children; (3) ovarian dysfunction, infertility, habitual abortion or unusual menopausal disorders; (4) symptoms of malaise and debility, such as undue fatigue, somnolence, mental asthenia and anxiety; (5) unexplained anemia; (6) colloid goiter, adenomatous goiter and cancer of the thyroid gland. If hypothyroidism is diagnosed, administration of thyroid hormone in increasing amounts, as determined by serial serum PBI tests, should be carried out indefinitely. Instruction of the patient is essential.
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PMID:Subclinical hypothyroidism. Recognition and treatment. 1398 2

In skeletal muscle, excitation may cause loss of K+, increased extracellular K+ ([K+]o), intracellular Na+ ([Na+]i), and depolarization. Since these events interfere with excitability, the processes of excitation can be self-limiting. During work, therefore, the impending loss of excitability has to be counterbalanced by prompt restoration of Na+-K+ gradients. Since this is the major function of the Na+-K+ pumps, it is crucial that their activity and capacity are adequate. This is achieved in two ways: 1) by acute activation of the Na+-K+ pumps and 2) by long-term regulation of Na+-K+ pump content or capacity. 1) Depending on frequency of stimulation, excitation may activate up to all of the Na+-K+ pumps available within 10 s, causing up to 22-fold increase in Na+ efflux. Activation of the Na+-K+ pumps by hormones is slower and less pronounced. When muscles are inhibited by high [K+]o or low [Na+]o, acute hormone- or excitation-induced activation of the Na+-K+ pumps can restore excitability and contractile force in 10-20 min. Conversely, inhibition of the Na+-K+ pumps by ouabain leads to progressive loss of contractility and endurance. 2) Na+-K+ pump content is upregulated by training, thyroid hormones, insulin, glucocorticoids, and K+ overload. Downregulation is seen during immobilization, K+ deficiency, hypoxia, heart failure, hypothyroidism, starvation, diabetes, alcoholism, myotonic dystrophy, and McArdle disease. Reduced Na+-K+ pump content leads to loss of contractility and endurance, possibly contributing to the fatigue associated with several of these conditions. Increasing excitation-induced Na+ influx by augmenting the open-time or the content of Na+ channels reduces contractile endurance. Excitability and contractility depend on the ratio between passive Na+-K+ leaks and Na+-K+ pump activity, the passive leaks often playing a dominant role. The Na+-K+ pump is a central target for regulation of Na+-K+ distribution and excitability, essential for second-to-second ongoing maintenance of excitability during work.
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PMID:Na+-K+ pump regulation and skeletal muscle contractility. 1450 6

Resistance to thyroid hormone (RTH) is a rare dominantly inherited disorder caused by mutations in the thyroid hormone receptor beta gene which lead to impaired tissue responsiveness to thyroid hormone (TH). RTH is characterized by elevated free thyroid hormone and unsuppressed thyrotropin (TSH) levels. Two types of the disorder have been recognized: selective pituitary resistance and generalized resistance to TH (GRTH). Triiodothyroacetic acid has been used in patients showing hypermetabolism, and L-T4 treatment in high doses has been suggested in GRTH if patients have signs of clinical hypothyroidism such as growth retardation and developmental delay. The outcome of long-term treatment of GRTH with L-T4 has not yet been reported. We report a 5 year-old boy who presented with severe growth retardation, fatigue and speech delay. He had hyperactivity despite feeling tired easily. Elevated TH levels with unsuppressed TSH and delayed bone age were determined by laboratory evaluation and he was diagnosed as GRTH. There was no clinicical evidence of hypermetabolism. We could not demonstrate any mutation in thyroid receptor beta1, beta2 or alpha gene of this patient and his parents. L-T4 treatment was started at conventional doses (6 microg/kg), and after 3 months of treatment T4 and TSH levels were suppressed successfully. In 12 months of treatment, no side effects were detected and surprisingly clinical symptoms improved without requirement for high doses of L-T4.
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PMID:Successful therapy with L-T4 in a 5 year-old boy with generalized thyroid hormone resistance. 1451 84

Despite being banned in many countries and having its use severely restricted in others, pentachlorophenol (PCP) remains an important pesticide from a toxicological perspective. It is a stable and persistent compound. In humans it is readily absorbed by ingestion and inhalation but is less well absorbed dermally. Its distribution is limited, its metabolism extensive and it is eliminated only slowly. Assessment of the toxicity of PCP is confounded by the presence of contaminants known to cause effects identical to those attributed to PCP. However, severe exposure by any route may result in an acute and occasionally fatal illness that bears all the hallmarks of being mediated by uncoupling of oxidative phosphorylation. Tachycardia, tachypnoea, sweating, altered consciousness, hyperthermia, convulsions and early onset of marked rigor (if death occurs) are the most notable features. Pulmonary oedema, intravascular haemolysis, pancreatitis, jaundice and acute renal failure have been reported. There is no antidote and no adequate data to support the use of repeat-dose oral cholestyramine, forced diuresis or urine alkalinisation as effective methods of enhancing PCP elimination in poisoned humans. Supportive care and vigorous management of hyperthermia should produce a satisfactory outcome. Chronic occupational exposure to PCP may produce a syndrome similar to acute systemic poisoning, together with conjunctivitis and irritation of the upper respiratory and oral mucosae. Long-term exposure has also been reported to result in chronic fatigue or neuropsychiatric features in combination with skin infections (including chloracne), chronic respiratory symptoms, neuralgic pains in the legs, and impaired fertility and hypothyroidism secondary to endocrine disruption. PCP is a weak mutagen but the available data for humans are insufficient to classify it more strongly than as a probable carcinogen.
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PMID:Pentachlorophenol poisoning. 1457 43


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