Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At least one form of periodic paralysis is a direct consequence of a mutation in a skeletal muscle, voltage-sensitive sodium channel--it was observed that many individual with this disease developed low serum potassium levels during paralytic episodes. Some families had hyperkalemic paralysis with serum potassium levels of 6 or 7 mEg/L during paralytic crises. In both hypokalemic and hyperkalemic paralysis one of the precipitants is a period of rest after exertion. In hypokalemic periodic paralysis carbohydrates may initiate weakness. In both hyper- and hypokalemic forms, the disorder is inherited as an autosomal dominant trait. During hypokalemic and hyperkalemic paralysis, one might respectively anticipate muscle hyperpolarization or depolarization. Has been observed a potassium-related abnormality of sodium conductance in the pathogenesis at least of the hyperkalemic form of periodic paralysis. The fact that TTX reverses the physiological defect suggested the hypothesis that the primary problem might be a mutation in a TTX-sensitive sodium channel. The protein consists of some 2000 amino acids with characteristic intracytoplasmic and extracellular domains as well a four remarkably conserved membrane spanning domains, each composed of six transmembrane of a polymorphism of the human sodium channel with hyperkalemic paralysis. When multipoint analysis was used to test for coinheritance of the disease with both Na-2 and growth hormone polymorphisms, a lod score of 7 was obtained. That is, the ratio of the probability of linkage to non-linkage is 10 million to one. When extracellular potassium is increased to 10 mM, the affected myotubes demonstrate strikingly abnormal channel behavior characterized by prolonged open times or repetitive opens throughout the voltage step. Potassium implicate as a primary factor triggering an abnormal sodium channel gating mode and, as a result, aberrant sodium current behavior. It was estimated that, for the normal channel, the probability of entering a non-inactivating mode was very low and independent of potassium. On the other hand, for the abnormal channel the probability of entering an inactive mode rises up to 5-fold with hyperkalemic. Four mutations have recently been detected in individuals with cold-sensitive paramyotenia congenital. Two of the cause amino acid substitutions within the III-IV intracytoplasmic loop. It is striking that one substitutes a valine for a glycine. An analysis of the molecular biology of each mutation should illuminate not only the disease phenotype but also biophysical properties of specific sub-regions of this muscle sodium channel.
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PMID:Molecular basis for hyperkalemic periodic paralysis. 1198 67

The authors report clinical observations in 12 acromegalic patients treated with long-acting octreotide (Sandostatin LAR, Novartis, 20 mg intramuscular injection per 28 days administered for 6-36 months). Clinically and hormonally active acromegaly was evidenced in all patients by the presence of typical clinical symptoms, increased serum growth hormone and insulin-like growth factor I concentrations, and by non-suppressible serum growth hormone levels after oral glucose administration. In all patients previous treatments (transsphenoidal surgery, pituitary irradiation and bromocriptine therapy) were uneffective or contraindicated, or they were refused by the patients. Octreotide test (Sandostatin, Novartis, 100 g subcutaneously) performed in all patients before treatment precisely predicted the hormonal effectiveness of long-acting octreotide treatment. Three-six months after therapy serum growth hormone levels decreased from 13.6 +/- 3.9 ng/ml (mean +/- SD) to 3.4 +/- 1.7 ng/ml, while insulin-like growth factor I concentrations decreased from 483 +/- 127 ng/ml to 248 +/- ng/ml. Of the 12 patients 7 (58%) had serum growth hormone levels considered as safe values (< 2.5 ng/ml), whereas in 9 patients (75%) serum insulin-like growth factor I concentrations returned to age- and sex-matched normals. Repeat pituitary magnetic resonance imaging performed in 8 patients treated longer than 1 year revealed a decrease of tumor size in 3 patients (37%). There was a considerable clinical improvement during treatment: severe headache, which was present in most patients, as well as perspiration, joint pain, swelling of extremities, and weakness markedly decreased or disappeared. These results indicate that long-acting octreotide offers a very effective treatment of choice in acromegalic patients in whom other previous therapies were ineffective, contraindicated, or refused.
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PMID:[Experience in treating acromegalic patients with long-acting octreotide]. 1206 62

Sepsis, excessive inflammation, multiple organ failure and weakness prolong the need for intensive care in critically ill patients. Furthermore, the risk of death is high in the prolonged critically ill patient (20% after two weeks and 30% after 3 weeks). In prolonged critical illness, protein hypercatabolism and relative preservation of adipose tissue with fatty infiltration of vital organ systems is present. In view of the crucial role of the hypothalamus-pituitary axis for metabolic homeostasis, we have studied this endocrine organ in the context of critical illness. The initial "adaptive" neuroendocrine response to critical illness illness consists primarily of activated anterior pituitary function. In the chronic phase of critical illness, a uniformly reduced pulsatile secretion of anterior pituitary hormones has been observed, whereby impaired function of target organs. A reduced availability of thyrotropin (TSH)-releasing hormone (TRH), gonadotropin (LH)-releasing hormone (GnRH), the endogenous ligand of the growth hormone (GH)-releasing peptide (GHRP) receptor (ghrelin) and, in very long-stay critically ill men also of GH-releasing hormone (GHRH), inferrentially appears involved. Pulsatile secretion of GH, TSH and LH can be re-amplified by relevant combinations of releasing factors which also substantially increases circulating levels of insulin-like growth factor (IGF)-I, GH-dependent IGF-binding proteins, thyroxine (T4), triiodothyronine (T3) and testosterone. Anabolism is only evoked when GH-secretagogues, TRH and GnRH are administered together whereas the effect of single hormone treatment is minor and accompanied by side effects. A remarkable observation was that a high serum concentration of IGF-binding protein 1 predicts death in the ICU. This observation challenged the classical dogma of adaptive hyperglycemia during critical illness. In a large prospective randomized clinical study (1548 patients), we showed that ICU mortality was reduced by 42% with strict normalization of glycemia using exogenous insulin infusion (N Engl J Med 2001). This was due to prevention of typical ICU complications such as sepsis, multiple organ failure and need for prolonged invasive organ support and intensive care. We conclude that the new concept of reduced stimulation of pituitary function in prolonged critically ill patients opens new therapeutic perspectives to reverse the paradoxical 'wasting syndrome' but that maintenance of strict normoglycemia with insulin is crucial to also increase the chances of survival of these patients.
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PMID:Endocrinology in intensive care medicine: new insights and therapeutic consequences. 1223 41

A 21 year-old female college student with a history of Turner syndrome at age 9, and 6-year growth hormone replacement therapy noticed weakness of right extremities when she got up on March 26, 2001. On admission, she showed right hemiparesis (4+/5) and hypesthesia on the right of body. The hemiparesis progressed (3-/5) in spite of antithrombotic therapy. Brain MRI revealed a high intensity lesion with a diameter of 1.5 cm in the posterior limb of the left internal capsule and putamen on DWI and T2WI. MR angiography and TC-CFI revealed no stenosis in her left middle cerebral artery, but > 50% stenosis in the horizontal portion (M1) of her right middle cerebral artery. Branch lesions were presumed to exist in the left M1. Non-atherosclerotic angiopathy, coagulopathy, and other conventional risk factors of brain infarction were not found. Pathogenesis of Turner syndrome might have played a role in the development of brain infarction in this patient.
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PMID:[A case of Turner syndrome complicated with brain infarction]. 1242 65

Critical illness precipitates a marked catabolic response, with protein wasting and loss of lean body mass. Prolongation of this response leads to impaired immunity, poor wound healing, loss of intestinal barrier function and muscle weakness, thereby increasing morbidity and perhaps mortality. Conventional nutritional support only partially ameliorates this process. Disappointingly, specific anabolic and anticatabolic strategies have so far met with only limited success, although recent findings, in particular studies demonstrating the potential value of aggressive insulin therapy and the administration of growth hormone secretagogues, have been encouraging.
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PMID:Anabolic strategies in critical illness. 1248 34

Is well being in the elderly be improved by hormone replacement therapy which compensate deficits accounting for generalized weakness, poor endurance, loss of muscle strength, impaired mobility and balance and decreased cognitive functions? Hormone replacement therapy of menopause has favorable effects on bone loss and decreased cognitive functions but also on several unpleasant symptoms--vasomotor instability, skin atrophy, mucosal dryness, anxiety and fatigue--but at the prize of increased incidence of cancer and cardiovascular morbidity. Decreased testosterone levels in elderly men are associated with increased fatigability, decreased muscle strength and bone mass and increased risks of accelerated atheromatosis. Testosterone substitution seems to be helpful but with side effects, particularly development of prostate cancer. Aging also affects adrenal function. The consequences of decreased DHEA production are still matter of debate. DHEA administration in elderly women seems to be associated with favorable effects on physical and psychological well being. Somatopause is characterized by a progressive decrease of growth hormone production starting as soon as the third decade. Growth hormone therapy has favorable effects on lean body mass, skin atrophy as well on body fat reduction. However, numerous side effects and the theoretical increased risk of cancer limit the use of growth hormone therapy in the elderly.
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PMID:[Hormone therapy of ageing: myths and realities]. 1551 74

Severe growth hormone (GH) deficiency (GHD) induces a well-defined clinical entity encompassing, amongst the most reported features, abnormalities of body composition, in particular increased fat mass, especially truncal, and reduced lean body mass. The results from virtually all treatment studies are in agreement that GH replacement improves the body composition profile of GHD patients by increasing lean body mass and reducing fat mass. More recently, the observations have been extended to adults with partial GHD, defined by a peak GH response to insulin-induced hypoglycaemia of 3-7 microg/l. These patients exhibit abnormalities of body composition similar in nature to those described in adults with severe GHD; these include an increase in total fat mass of around 3.5 kg and a reduction of lean body mass of around 5.5 kg. The increase in fat mass is predominantly distributed within the trunk. The degree of abnormality of body composition is intermediate between that of healthy subjects and that of adults with GHD. The impact of GH replacement on body composition in adults with GH insufficiency, although predictable, has not been formally documented. The skeleton is another biological endpoint affected by GH status: in adults with severe GHD, low bone mass has been reported using dual energy x-ray absorptiometry (DEXA) and other quantitative methodologies. The importance of low bone mass, in any clinical setting, is as a surrogate marker for the future risk of fracture. Several retrospective studies have documented an increased prevalence of fractures in untreated GHD adults. Hypopituitary adults with severe GHD have reduced markers of bone turnover which normalize with GH replacement, indicating that GH, directly or via induction of insulin-like growth factor-I, is intimately involved in skeletal modelling. Whilst the evidence that GH plays an important role in the acquisition of bone mass during adolescence and early adult life is impressive, the impact of GHD acquired later in adulthood is less clear. Recently we examined the relationship between bone mineral density (BMD) and age in 125 untreated adults with severe GHD using DEXA. A significant positive correlation was observed between BMD (z-scores) and age at all skeletal sites studied. Overall, few patients, except those aged less than 30 years, had significantly reduced bone mass (i.e. a BMD z-score of less than -2); correction of BMD to provide a pseudo-volumetric measure of BMD suggested that reduced stature of the younger patients may explain, at least in part, this higher frequency of subnormal BMD z-scores. Despite normal BMD, however, an increase in fracture prevalence may still be observed in elderly GHD adults as a consequence of increased falls related to muscle weakness and visual field defects.
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PMID:Impact of growth hormone status on body composition and the skeleton. 1553 97

A patient with Duchenne muscular dystrophy (DMD) and growth hormone (GH) deficiency is described who had no clinical evidence of muscular weakness before initiation of GH replacement therapy. Treatment with human GH resulted in appearance of symptoms of easy fatigability and proximal muscle weakness. Thorough investigations including serum creatinine phosphokinase (CK) levels is recommended in every patient with GH deficiency before starting GH replacement therapy.
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PMID:Duchenne muscular dystrophy with associated growth hormone deficiency. 1556 63

Besides lifestyle and environmental factors, the life-long exposure to the endocrine milieu of gonadal steroids is a determining factor to gender specific features of aging. In contrast to women, men do not experience a sudden cessation of gonadal function comparable to menopause. However, cross-sectional and longitudinal population studies demonstrate that the hormones with anabolic actions (e.g. testosterone [T], growth hormone, insulin-like growth factor [IGF]-1, dehydroepiandrosterone) do decrease progressively with aging in healthy men, and chronic systemic illnesses accelerate this process. In addition, estrogen has recently been established to be essential for normal physiology of the male. The slow progressive decline of the hypothalamic-pituitary-gonadal (HPG) function is thought to be responsible for many common signs and symptoms of aging men, such as general weakness, sexual dysfunction, and increased fat mass. There is a large inter-individual variation in sex hormone levels cross-sectionally within given age groups as well as longitudinally with aging. A contributing factor to this variability are the numerous functionally significant polymorphisms that have been detected in the receptors for androgen and estrogen. In this review, we summarize the recent information on some common polymorphisms in androgen and estrogen receptor genes and their effect on gender specific and aging-related symptoms and diseases of men.
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PMID:Polymorphisms in androgen and estrogen receptor genes: effects on male aging. 1591 85

The mechanisms by which aging induces muscle impairment are not well understood yet. We studied the impact of aging on Ca2+ homeostasis in the slow-twitch soleus and the fast-twitch extensor digitorum longus (EDL) muscles of aged rats by using the fura-2 fluorescent probe. In both muscles aging increases the resting cytosolic calcium concentration ([Ca2+]i). This effect was independent on calcium influx since a reduced resting permeability of sarcolemma to divalent cations was observed in aged muscles likely due to a reduced activity of leak channels. Importantly the effects of aging on resting [Ca2+]i, fiber diameter, mechanical threshold and sarcolemmal resting conductances were less pronounced in the soleus muscle, suggesting that muscle impairment may be less dependent on [Ca2+]i in the slow-twitch muscle. The treatment of aged rats with growth hormone restored the resting [Ca2+]i toward adult values in both muscles. Thus, an increase of resting [Ca2+]i may contribute to muscle weakness associated with aging and may be considered for developing new therapeutic strategies in the elderly.
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PMID:Fiber type-related changes in rat skeletal muscle calcium homeostasis during aging and restoration by growth hormone. 1615 53


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