Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0221002 (primary hyperparathyroidism)
 4,921 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Parathyroidectomy is the only option available for the cure of primary hyperparathyroidism (PHPT), which is a common endocrine disorder and often causes secondary osteoporosis. This disease is now recognized as a disorder with few overt manifestations, presenting most often as mild or asymptomatic hypercalcemia. There are accumulating PHPT patients who are unwilling or are unsuitable for surgery. In these patients, bisphosphonate is a most useful candidate as supportive therapy. Calcimimetic agent which modulates the activity of calcium-sensing receptor on the surface of parathyroid cell and suppresses the secretion of parathyroid hormone, would be an effective nonsurgical approach for management of PHPT.
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PMID:[Medical treatment for primary hyperparathyroidism]. 1632 75

Primary hyperparathyroidism (PHPT) is characterized by excessive PTH secretion in respect to calcium homeostasis needs, due to parathyroid adenoma (80% of cases), hyperplasia (15-20%), or carcinoma (1-2%). In familial forms of PHPT, several mutations have an established role: menin gene for MEN type 1, RET for MEN type 2a, calcium-sensing receptor gene for familial hypocalciuric hypercalcemia, parafibromin gene for PHPT-jaw tumour and carcinoma. Etiology of sporadic adenomas (80% of PHPT cases) is less defined, being most commonly found a mutation of menin gene or activation of PRAD1 oncogene. In recent years, the classical features of the disease became less common. Typically, bone involvement is now represented by a reduced bone mass at skeletal sites more rich in cortical tissue. Prominently trabecular skeletal sites are relatively spared, because of the anabolic effects of a slight PTH excess on trabecular tissue. PHPT patients may have increased fracture risk, though it is not clear why bone damage is more severe in a subgroup of patients. Clinical features of hypercalcemia may be fatigue, anorexia, thirst, and polyuria. Vague neurological and psychiatric symptoms, such as weakness, anxiety, depression, paresthesias, and muscular cramps may ameliorate after parathyroidectomy. Recent reports indicate increased cardiovascular mortality in PHPT patients. Diagnosis is based on the detection of hypercalcemia, together with inappropriately high serum PTH levels. Preoperative localization of the diseased glands is mandatory in persistent or recurrent PHPT, as like as when minimally invasive surgery is planned. High resolution ultrasonography and SPECT double-phase 99m Tc-sestamibi scintigraphy are the most commonly employed techniques. Intraoperatory PTH assay may confirm successful surgery when serum concentrations decrease more than 50%. Surgical therapy is indicated in patients with renal or skeletal complications, such as in those with previous parathyrotoxic crisis. Many surgeons in recent years adopted minimally invasive parathyroidectomy. Medical treatment is an option for patients unwilling or unfitted for surgery because of severe concomitant diseases. Employed therapy includes estrogens, SERMs, bisphosphonates and calcimimetics.
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PMID:[Primary hyperparathyroidism]. 1638 70

Cinacalcet is a new drug with antiparathyroid effects that belongs to the class of calcimimetics. It increases the sensitivity of the calcium-sensing receptor (CaSR) to calcium, thus inducing a decrease in plasma parathyroid (PTH) levels. In patients with uncontrolled secondary hyperparathyroidism due to uremia, cinacalcet has been shown to decrease the levels of PTH even in those optimally treated with calcium and 1-ahydroxylated vitamin D. Cinacalcet decreases plasma calcium and plasma PTH levels in patients with primary hyperparathyroidism or parathyroid cancer.
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PMID:[Cinacalcet--a new drug for the treatment of secondary hyperparathyroidism in patients with uraemia, parathyroid cancer or primary hyperparathyroidism]. 1639 59

It has long been recognized that the secretion of PTH by chief cells in the parathyroid gland is regulated by extracellular ionized calcium. The molecular mechanism by which extracellular Ca2+ performs this feat was deduced by the cloning of the extracellular calcium-sensing receptor (CaSR) in 1993 in the laboratories of Brown and Hebert. The CaSR is a G protein-coupled cell surface receptor that belongs to family 3 of the GPCR superfamily. The CaSR senses the extracellular ionic activity of the divalent minerals Ca2+ and Mg2+ and translates this information, via a complex array of cellular signaling pathways, to modify cell and tissue function. Genetic studies have demonstrated that the activity of this receptor determines the steady-state plasma calcium concentration in humans by regulating key elements in the calcium homeostatic system. CaSR agonists (calcimimetics) and antagonists (calcilytics) have been identified and have provided both current and potential therapies for a variety of disorders. Calcimimetics can effectively reduce PTH secretion in all forms of hyperparathyroidism. They are likely to become a major therapy for secondary hyperparathyroidism associated with renal failure and for treatment of certain patients with primary hyperparathyroidism. On the therapeutic horizon are calcilytics that can transiently increase PTH and may prove useful in the treatment of osteoporosis.
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PMID:Therapeutic use of calcimimetics. 1640 54

The lack of overt elevation of serum calcium concentration in some patients suffering from primary hyperparathyroidism is an intriguing clinical phenomenon. Previous studies have substantiated abnormal parathyroid tissue in these patients, but the extent and mode of derangements remained largely undefined. The parathyroid tissues from patients of normocalcemic primary hyperparathyroidism (NCPHPT) and those having normal parathyroid glands, hypercalcemic primary hyperplasia, secondary hyperplasia, and adenoma were compared by undertaking quantitative immunohistochemistry analysis on tissue microarray. The statistic results suggested that the parathyroid tissue of NCPHPT approximates more to normal gland than to its counterpart in other groups of parathyroid proliferative diseases in terms of the lack of significant alterations of calcium-sensing receptor (CaSR), chromogranin A (CGA), parathyroid hormone (PTH), and proliferation index (Ki67). On the other hand, the depressed vitamin D receptor (VitDR) and elevated cyclin D1 (CyD1) of NCPHPT indicated the inherent functional abnormalities in parathyroid cells. Our results imply that inherent functional disengagement may exist between CaSR and CyD1 or between CaSR and VitDR or both in parathyroid cells of symptomatic NCPHPT. Lack of enhanced release of CGA and PTH and discordance between proliferative activity and CyD1 expression in parathyroid cells may further hinder the development of hypercalcemia.
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PMID:Normocalcemic primary hyperparathyroidism in patients with recurrent kidney stones: pathological analysis of parathyroid glands. 1667 Sep 29

Clinical studies have been performed to determine the effect of cinacalcet HCl (cinacalcet), an allosteric modulator of the calcium-sensing receptor (CaR), on primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism of uremia (SHPT). However, no in vitro studies on human parathyroid cells have been reported to date. In this study, the inhibitory effect of cinacalcet on PTH secretion was analyzed in primary cultured parathyroid cells obtained from patients. The investigation involved three PHPT and three SHPT patients subjected to therapeutic parathyroidectomy. Notably, all SHPT patients were resistant to intravenous vitamin D analogue therapy. Removed parathyroid tumors were used for immunohistochemistry and parathyroid cell primary culture. Immunohistochemical analyses revealed diminished expression of CaR and vitamin D receptor (VDR) in all parathyroid tumors. PTH secretion from cultured parathyroid cells of PHPT and SHPT patients was suppressed by extracellular Ca2+ and cinacalcet in a dose-dependent manner. Rates of suppression of PTH secretion in PHPT and SHPT by cinacalcet (1000 nmol/l) were 61% +/- 21% and 61% +/- 19%, respectively. Cinacalcet demonstrates significant potency in the suppression of PTH secretion in primary cultured human parathyroid cells in vitro, despite reduced levels of the target protein, CaR. Data from this in vitro analysis support the clinical application of cinacalcet in PHPT and SHPT therapy.
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PMID:Direct in vitro evidence of the suppressive effect of cinacalcet HCl on parathyroid hormone secretion in human parathyroid cells with pathologically reduced calcium-sensing receptor levels. 1681 24

The calcium-sensing receptor has a key role in calcium homeostasis, it is involved in the regulation of the serum calcium level within minutes via the secretion and action of parathyroid and the excretion of calcium in the kidney in a negative feedback manner. Mutations of the calcium sensing receptor gene leads to inactivating and activating mutations resulting in diseases with hypercalcaemia and hypocalcaemia. The loss of function mutations are associated with familial benign hypocalciuric hypercalcaemia (FHH), an autosomal dominant disease characterised by lifelong mild hypercalcaemia, low urinary calcium excretion, and inappropriate high parathyroid hormone levels, sometimes difficult to distinguish from mild asymptomatic primary hyperparathyroidism. Patients with FHH did not profit from parathyroidectomy, a calcium lowering therapy is not necessary. The gain of function mutations of the calcium-sensing receptor are associated with autosomal dominant hypocalcaemia (ADH), a disease characterised by a generally asymptomatic hypocalcaemia, inappropriately high urinary calcium excretion and normal PTH levels. A therapy to raise the serum calcium concentration has to be done carefully and is only indicated in symptomatic patients, because of enhancement of hypercalciuria with the risk of nephrocalcinosis and nephrolithiasis. Molecular genetic analysis of the calcium sensing receptor gene facilitates the sometimes difficult diagnosis. The development of compounds modulating the calcium sensing receptor function and thereby the section of PTH may become an important role in treatment of diseases of calcium metabolism.
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PMID:The role of the extracellular calcium-sensing receptor in health and disease. 1703 19

Primary hyperparathyroidism is a disease in which somatic chromosomal defects such as activations of oncogenes or inactivations of tumor suppressor genes enhance chromosomal parathyroid cell growth. Decreased calcium-sensing receptor causes oversecretion of PTH from abnormal parathyroid cells. Oversecreted PTH enhances bone turnover and finally exhibits bone fragility. In this review, the indications of parathyroidectomy and the effects of parathyroidectomy on bone in primary hyperparathyroidism are discussed.
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PMID:[Parathyroid and bone. Indication for parathyroidectomy in primary hyperparathyroidisms]. 1805 66

An increasing number of patients are diagnosed with primary hyperparathyroidism after having hypercalcaemia detected incidentally during routine biochemical screening. Many are asymptomatic at the time of diagnosis. An 80-year-old woman was found to have asymptomatic hypercalcaemia. Initial investigations suggested a diagnosis of primary hyperparathyroidism. Subsequent investigations revealed that, in fact, she had familial hypocalciuric hypercalcaemia. Direct DNA sequencing of the calcium-sensing receptor (CASR) gene confirmed that the patient was heterozygous for c.2501delC, a novel frame shift mutation predicted to cause loss of function of the CASR gene. Several other family members were subsequently found to carry the same mutation. Suspected cases of hypocalciuric hypercalcaemia should be confirmed by detection of mutations within the CASR gene. Establishing the correct diagnosis will enable the patient and family members to avoid unnecessary investigations or operations.
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PMID:A novel CASR gene mutation in an octogenarian with asymptomatic hypercalcaemia. 1852 93

Cinacalcet is a type II calcimimetic agent which is an allosteric modulator of the calcium-sensing receptor (CaR) located on the surface of the parathyroid cells. Cinacalcet increases the sensitivity of CaR via binding to the transmembrane region of CaR. Increasing sensitivity of CaR causes reduced secretion of parathyroid hormone (PTH) and suppression of serum calcium levels. Cinacalcet has recently been approved by Federal Drug Administration (FDA) for the treatment of patients with secondary hyperparathyroidism on maintenance dialysis and hypercalcemia in patients with parathyroid cancer. It is used also in Europe for both indications. Several controlled studies have shown that cinacalcet is effective in normalizing serum calcium levels also in primary hyperparathyroidism. Cinacalcet is metabolized primarily in the liver by N-dealkylation leading to carboxylic acid and oxidation of naphthalene ring to form dihydrodiols. The safety and optimal dosage of the drug in hypercalcemic patients with liver impairment remains unclear. We present a patient with Child-Pugh B class primary biliary cirrhosis who presented with moderate hypercalcemia and was diagnosed as primary hyperparathyroidism. As she refused having parathyroid surgery for her parathyroid adenoma at first, her hypercalcemia was treated successfully with 30 mg/day cinacalcet for 6 months. Cinacalcet was discontinued after 6 months. Her calcium level increased gradually. As she accepted surgery this time, her parathyroid adenoma was removed by minimally invasive parathyroidectomy. Parathyroid adenoma was confirmed pathologically. Her calcium levels maintained within the normal ranges after surgery.
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PMID:Hypercalcemia of primary hyperparathyroidism was treated by cinacalcet in a patient with liver cirrhosis. 1856 Oct 96


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