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

The stress system coordinates the adaptive responses of the organism to stressors of any kind.(1). The main components of the stress system are the corticotropin-releasing hormone (CRH) and locus ceruleus-norepinephrine (LC/NE)-autonomic systems and their peripheral effectors, the pituitary-adrenal axis, and the limbs of the autonomic system. Activation of the stress system leads to behavioral and peripheral changes that improve the ability of the organism to adjust homeostasis and increase its chances for survival. The CRH and LC/NE systems stimulate arousal and attention, as well as the mesocorticolimbic dopaminergic system, which is involved in anticipatory and reward phenomena, and the hypothalamic beta-endorphin system, which suppresses pain sensation and, hence, increases analgesia. CRH inhibits appetite and activates thermogenesis via the catecholaminergic system. Also, reciprocal interactions exist between the amygdala and the hippocampus and the stress system, which stimulates these elements and is regulated by them. CRH plays an important role in inhibiting GnRH secretion during stress, while, via somatostatin, it also inhibits GH, TRH and TSH secretion, suppressing, thus, the reproductive, growth and thyroid functions. Interestingly, all three of these functions receive and depend on positive catecholaminergic input. The end-hormones of the hypothalamic-pituitary-adrenal (HPA) axis, glucocorticoids, on the other hand, have multiple roles. They simultaneously inhibit the CRH, LC/NE and beta-endorphin systems and stimulate the mesocorticolimbic dopaminergic system and the CRH peptidergic central nucleus of the amygdala. In addition, they directly inhibit pituitary gonadotropin, GH and TSH secretion, render the target tissues of sex steroids and growth factors resistant to these substances and suppress the 5' deiodinase, which converts the relatively inactive tetraiodothyronine (T(4)) to triiodothyronine (T(3)), contributing further to the suppression of reproductive, growth and thyroid functions. They also have direct as well as insulin-mediated effects on adipose tissue, ultimately promoting visceral adiposity, insulin resistance, dyslipidemia and hypertension (metabolic syndrome X) and direct effects on the bone, causing "low turnover" osteoporosis. Central CRH, via glucocorticoids and catecholamines, inhibits the inflammatory reaction, while directly secreted by peripheral nerves CRH stimulates local inflammation (immune CRH). CRH antagonists may be useful in human pathologic states, such as melancholic depression and chronic anxiety, associated with chronic hyperactivity of the stress system, along with predictable behavioral, neuroendocrine, metabolic and immune changes, based on the interrelations outlined above. Conversely, potentiators of CRH secretion/action may be useful to treat atypical depression, postpartum depression and the fibromyalgia/chronic fatigue syndromes, all characterized by low HPA axis and LC/NE activity, fatigue, depressive symptomatology, hyperalgesia and increased immune/inflammatory responses to stimuli.
 ...
PMID:Hypothalamic-pituitary-adrenal axis, neuroendocrine factors and stress. 1237 95

Acromegaly is a chronic disorder invariably caused by a growth hormone (GH)-secreting pituitary tumour and is characterised by disabling symptoms (sweating, arthralgia, headache, paraesthesiae, fatigue), significant comorbidities (diabetes mellitus, hypertension, sleep apnoea), and premature mortality. Symptomatic control can be achieved by lowering insulin-like growth factor-I (IGF-I) concentrations to within the age-adjusted normal range, and survival can be improved to match that of the general population. However, even with optimal surgery and current medical therapies (dopamine agonists, somatostatin analogues), 30% to 50% of patients do not achieve target concentrations of IGF-I and GH. Pegvisomant is a new GH-receptor antagonist that blocks GH activity by inhibiting functional dimerisation of GH-receptors. Given as subcutaneous injections at dosages of 10 mg, 15 mg, or 20 mg/day for 3 Months, pegvisomant normalised serum IGF-I concentrations in, respectively, 54%, 81%, and 89% of acromegalic patients. Moreover, long-term pegvisomant therapy normalised IGF-I concentrations in 97% of patients treated for 12 Months or longer, with no evidence of tachyphylaxis. Pegvisomant is the most effective medical therapy, reported to date, in terms of normalisation of circulating IGF-I concentrations. In addition, pegvisomant appears to be safe and well tolerated. Although additional long-term studies are required to further assess safety, the introduction of this innovative treatment should allow for optimal disease control in patients with acromegaly.
 ...
PMID:Pegvisomant: an advance in clinical efficacy in acromegaly. 1267 Feb 98

Octreotide long-acting release (LAR) is a somatostatin analogue designed for once monthly intramuscular injection. As with endogenous somatostatin, octreotide LAR inhibits secretion of growth hormone (GH) as well as various other peptide hormones. In the treatment of acromegaly, octreotide LAR effectively controlled the secretion of GH and insulin-like growth factor-1 (IGF-1) in about 55-70% of patients (n > 100) who had previously been treated with somatostatin analogues, a similar degree of control to that observed with subcutaneous octreotide and lanreotide slow release (SR). Progressive control of serum levels of GH and IGF-1 was achieved with octreotide LAR in clinical studies of up to 4 years' duration. In addition, primary therapy with octreotide LAR provided effective control of GH and IGF-1 secretion, particularly in patients with a pretreatment GH level <20 microg/L. The percentage of patients achieving a target serum GH level of <2-2.5 micro g/L or normal IGF-1 levels was significantly greater with octreotide LAR 10, 20 or 30 mg every 28 days than with lanreotide SR 30 mg every 7-14 days in a large (n = 125) sequential, 6-month study, but was not significantly different between treatment groups in a small, randomised, nonblind, parallel group study of previously untreated patients. The volume of pituitary tumour shrinkage achieved with octreotide LAR or lanreotide SR was also similar ( approximate, equals 33% after 24 months). Acromegaly symptoms, such as headache, increased perspiration, paraesthesia, fatigue and osteoarthralgia were improved during treatment with octreotide LAR or lanreotide SR. Overall, octreotide LAR is generally well tolerated by most patients. The incidence of gastrointestinal symptoms is about 30% but, in most cases, events are transient and mild to moderate. Gallbladder abnormalities (sediment, sludge, microlithiasis and gallstones) can occur, but only 1% have become symptomatic to date. The prevalence of biliary abnormalities did not change after switching from subcutaneous octreotide, or from lanreotide SR, to octreotide LAR. Glucose metabolism can be affected by octreotide LAR in some patients; about 15% become hyperglycaemic, usually mild in severity. In summary, octreotide LAR controls GH and IGF-1 secretion in about 55-70% of patients with acromegaly. Octreotide LAR is administered intramuscularly every 28 days, offering improved patient compliance and convenience over three-times-daily subcutaneous octreotide. Long-term therapy provides progressive control of serum GH and IGF-1 levels, and is generally well tolerated by most patients. Thus, for the medical management of acromegaly, octreotide LAR is an effective, well tolerated and convenient treatment option.
 ...
PMID:Octreotide long-acting release (LAR): a review of its use in the management of acromegaly. 1460 59

For more than 30 years, growth hormone (GH) has been observed to be preferentially secreted during deep, slow-wave sleep (SWS). However, the mechanisms that underlie this robust relationship that links anabolic processes in the body with behavioral rest and decreased cerebral metabolism remain to be elucidated. Current evidence indicates that GH secretion during the beginning of sleep appears to be primarily regulated by GH-releasing hormone (GHRH) stimulation occurring during a period of relative somatostatin withdrawal, which also is associated with elevated levels of circulating ghrelin. Apparently, two populations of GHRH neurons need to be simultaneously active to stimulate, in a coordinated fashion, SWS and pituitary GH release. Pharmacological interventions that are capable of increasing the duration and/or the intensity of SWS such as oral administration of gamma-hydroxybutyrate (GHB), also increase the rate of GH release. Because the normal negative feedback exerted by GH on central GHRH is inoperative in patients with GH deficiency, it is possible that the decreased energy levels and fatigue often reported by GH-deficient adults partly reflect an alteration in sleep-wake regulation. Preliminary data from a sleep study of adults with GH deficiency using wrist actigraphy for 6 nights at home and polysomnography in the laboratory indeed show decreased total sleep time and increased sleep fragmentation in GH-deficient patients as compared with normal controls.
 ...
PMID:Reciprocal interactions between the GH axis and sleep. 1513 71

The long-term impact of acromegaly on subjective well-being after treatment of GH excess is unclear. Therefore, we evaluated quality of life by validated questionnaires in a cross-sectional study of 118 successfully treated acromegalic patients. The initial treatment was transsphenoidal surgery in most patients (92%), if necessary followed by radiotherapy or octreotide. All patients were in remission at the time of assessment (GH, <1.9 mug/liter; normal IGF-I for age). General perceived well-being was reduced compared with controls for all subscales (P < 0.001) as measured by the Nottingham Health Profile and the Short Form-36. Acromegalic patients also had lower scores on fatigue (Multidimensional Fatigue Index) and anxiety and depression (Hospital Anxiety and Depression Scale). Radiotherapy was associated with decreased quality of life in all subscales except for the Hospital Anxiety and Depression Scale, and worsened quality of life significantly, according to the fatigue scores. Somatostatin analog treatment was not associated with improved quality of life. Independent predictors of quality of life were age (physical subscales and Nottingham Health Profile), disease duration (social isolation and personal relations), and radiotherapy (physical and fatigue subscales). In conclusion, patients cured after treatment for acromegaly have a persistently decreased quality of life despite long-term biochemical cure of GH excess. Radiotherapy especially is associated with a reduced quality of life.
 ...
PMID:Decreased quality of life in patients with acromegaly despite long-term cure of growth hormone excess. 1553 83

Active acromegaly is associated with significant comorbidity and reduced quality of life. However, the prevalence of comorbidity after long-term remission is not established. Therefore, we assessed the presence of comorbidity in 118 patients in long-term remission after surgery, radiotherapy, and/or somatostatin analog treatment according to strict biochemical criteria of serum GH and IGF-I concentrations and evaluated the impact of comorbidity on quality of life. The mean duration of remission was 12.0 +/- 7.4 yr, and mean actual IGF-I sd scores were 0.6 +/- 1.7. Self-reported joint problems occurred in 77% of patients, hypertension in 37%, a history of myocardial infarction in 9%, and diabetes mellitus in 11%. The presence of joint problems was not related to GH and IGF-I levels, active disease duration, or age. Joint complaints had significant negative impact on quality of life. Patients with a history of myocardial infarction had reduced scores for general health, depression, and fatigue, and diabetes mellitus was associated with reduced scores for anxiety and sleep. In conclusion, acromegalic patients had a high prevalence of joint-related comorbidity and hypertension despite long-term control of GH excess. Especially, joint complaints contributed to a reduced perceived quality of life in these patients.
 ...
PMID:Morbidity after long-term remission for acromegaly: persisting joint-related complaints cause reduced quality of life. 1574 Dec 57

The availability of recombinant human GH and somatostatin analogs has resulted in widespread treatment for adults with GH deficiency (GHD) and those with GH excess (acromegaly). Despite being at opposite ends of the spectrum in terms of their GH/IGF-I axis, both of these populations experience overlapping somatic impairments. Adults with untreated GHD have low circulating levels of IGF-I that manifest as altered body composition with increased fat and reduced lean body and skeletal muscle mass. At the other end of the spectrum, adults with GH excess, who have elevated levels of IGF-I, also have altered body composition. Impairments that result from disorders of either GHD or GH excess are both associated with increased functional limitations, such as reduced ability to walk quickly for prolonged periods, and poorer health-related quality of life (HR-QoL). Adults with untreated GHD and GH excess both commonly complain of excessive fatigue that seems to be associated more with impaired aerobic than muscular performance. Several studies have documented that administration of GH or somatostatin analogs to adults with GHD or GH excess, respectively, ameliorates abnormal biochemical profile and the associated somatic impairments. However, whether these improvements translate into improved physical function in adults with GHD or GH excess remains largely unknown, and their impact on HR-QoL controversial. Review of placebo-controlled trials to date suggests that GH and somatostatin analogs have greater effects on gas exchange and aerobic performance than as anabolic agents on skeletal muscle mass and function. Future investigations should include dose-response studies to establish the optimal combination of pharmacological agents plus exercise required to improve not only biochemical markers but also physical function and HR-QoL in adults with GHD or GH excess.
 ...
PMID:The influence of growth hormone status on physical impairments, functional limitations, and health-related quality of life in adults. 1654 84

Somatostatinomas are rare tumors; ampullary somatostatinomas are very rare. We report a case of a small pure somatostatin-producing neuroendocrine tumor of ampulla of Vater in a 54-year-old woman with neither neurofibromatosis nor somatostatinoma syndrome, "incidentally" discovered during an abdominal computed tomography. The patient initially refused other adjunctive exams but after 2 years she was admitted, presenting with itch, night sweats, severe fatigue, and unintentional weight loss. The size of the tumor (1.5 cm) and the other radiologic findings had not changed since the abdominal CT scan 2 years before. The somatostatin, gastrin, glucagons, serotonin, vasoactive intestinal peptide, dopamine, norepinephrine, epinephrine, and calcitonin plasma levels were normal. ERCP-obtained biopsies revealed a neuroendocrine tumor with psammoma bodies; immunohistochemical profile was positive for chromogranin and somatostatin. The patient underwent surgery; intraoperative histologic examination of lymph nodes sampling of perihepatic and periduodenal lymph nodes was negative for metastasis. We performed, therefore, a transduodenal ampullectomy. The patient continues to do well at 3 years' follow-up with no evidence of local or distance recurrence of disease.
 ...
PMID:Incidental small ampullary somatostatinoma treated with ampullectomy 2 years after diagnosis. 1696 13

A 72-year-old woman visited a clinic for anorexia and general fatigue but no particular abnormality was detected by routine examination at that time. Thereafter, she experienced gradually increasing dyspnea and chest X ray showed right pleural effusion. Idiopathic chylothorax was diagnosed due to the milky effusion with a high concentration of triglyceride (2618 mg/dl) and no apparent causative disease. Irrespective of treatments including dietary restriction, drainage of the pleural space, and somatostatin injections, her effusion did not reduce. The leakage of lymph fluid from the right posterior mediastinum was identified by lymphatic scintigraphy and she was successfully treated with surgical ligation of the thoracic ducts.
 ...
PMID:[Case of idiopathic chylothorax successfully treated with surgical ligation of thoracic ducts]. 1801 31

The approach to a patient with acromegaly and persistent disease after surgery requires a complex diagnostic assessment. Acromegaly is a chronic and insidious disease that is associated with multisystem comorbidities, including cardiovascular disease, hypertension, sleep apnea syndrome, colon polyposis, arthropathy, and metabolic complications including glucose intolerance and type 2 diabetes mellitus. Patients also have a variety of signs and symptoms, including headache, arthralgias, carpal tunnel syndrome, sweating, fatigue, and psychological issues that impact significantly on quality of life. The recommended approach to the evaluation of the postoperative patient includes a biochemical assessment, with measurement of serum IGF-I along with a glucose-suppressed GH value, radiological assessment to determine location of residual tumor and presence of mass effects, a physical examination for evidence of skeletal and soft tissue overgrowth and related signs of acromegaly, and a thorough clinical assessment for the presence of comorbidities. Repeat surgery is indicated if there is residual tumor that is surgically accessible and there may be a chance for surgical cure, or if there are persistent mass effects upon the optic chiasm. Otherwise, medical therapy is indicated, utilizing somatostatin analogs, dopamine agonists, and pegvisomant, a GH receptor antagonist. Radiation therapy is usually relegated to situations where medical therapy is ineffective or poorly tolerated or where patients would prefer not to sustain the cost of long-term medical therapy. The choice of therapy requires close dialog among endocrinologists, neurosurgeons, radiation therapists, and neuroophthalmologists for optimal care of patients.
 ...
PMID:Approach to the patient with persistent acromegaly after pituitary surgery. 2082 64


<< Previous 1 2 3 4 Next >>