Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The peptide hormone calcitonin is widely used therapeutically in the treatment of bone disorders such as Paget's disease, osteoporosis, and the hypercalcemia of some malignancies. However, emerging evidence suggests the actions of calcitonin via its G protein-coupled receptor, the calcitonin receptor, may not be limited to bone. Calcitonin receptors have also been identified in the central nervous system, testes, skeletal muscle, lymphocytes, and the placenta. We are now becoming aware that the complexity of the calcitonin response mediated by the calcitonin receptor can be influenced by accessory proteins, receptor isoforms, genetic polymorphisms, developmental and/or transcriptional regulation, feedback inhibition, and the specific cellular or tissue background. This article discusses what is known about the molecular and pharmacological actions of the calcitonin receptor and highlights areas of current research.
 ...
PMID:Molecular pharmacology of the calcitonin receptor. 1252 40

Hypercalcemia is a common, life-threatening metabolic disorder that can be associated with cancer. Its pathophysiology includes enhanced osteoclastic bone resorption and decreased renal excretion of extracellular calcium. Symptoms of hypercalcemia include nausea, vomiting, bone pain, polyuria, renal insufficiency, bradycardia, and arrhythmia. The goals of medical therapy are to inhibit bone resorption and promote renal calcium excretion. Hydration is the first step in management. Treatments for hypercalcemia include phosphates, calcitonin, bisphosphonates, and gallium nitrate. Although intravenous phosphates prevent intestinal calcium absorption and inhibit mineral and bone matrix resorption, serious adverse events include renal failure, hypotension, extraskeletal calcification, and severe hypocalcemia. Calcitonin has a rapid onset of action and can lower serum calcium concentrations within hours, but its usefulness is limited by its short duration of effect and the development of tachyphylaxis. Bisphosphonates are effective inhibitors of bone resorption but appear to have decreased response rates in hypercalcemic patients with high levels of parathyroid-related protein. Gallium nitrate, an antitumor agent noncytotoxic to osteoclasts and bone cells, appears to be more effective than pamidronate, etidronate, and calcitonin in the treatment of cancer-related hypercalcemia. Importantly, unlike bisphosphonates, gallium nitrate is effective in both parathyroid-related protein-mediated and non-parathyroid-related protein-mediated hypercalcemia.
 ...
PMID:Treatment of cancer-related hypercalcemia: the role of gallium nitrate. 1277 55

Severe hypercalcemia is a life-threatening medical emergency. It is most commonly caused by malignant tumors, but can also be caused by primary hyperparathyroidism or less often by a dysregulated production of active vitamin D in granulomatous disorders. Symptoms include nausea, vomiting, renal insufficiency, severe dehydration, lethargy, confusion, and even coma. Severity of symptoms, calcium concentrations, and the overall status of the patient are important considerations in selecting appropriate therapy. Hydration to correct volume depletion is the cornerstone of acute therapy. Loop diuretics may be added to saline hydration after extracellular fluid volume has been replenished to enhance urinary calcium excretion and mitigate fluid overload from rehydration. Calcitonin and intravenous infusion of bisphosphonates reduce serum calcium levels by interfering with calcium release from the skeleton. Dialysis with a low or zero calcium dialysate is reserved for patients who are refractory to these measures. Corticosteroids are effective with hypercalcemia due to increased vitamin D levels and in multiple myeloma.
 ...
PMID:[Hypercalcemic crisis]. 1468 84

Calcitonin is a peptide hormone that may decrease serum calcium levels. This case report describes a patient with a calcitonin-producing islet cell tumor who was also hypercalcemic. Parathyroid hormone-related peptide (PTHrP) levels were elevated. No other cause for hypercalcemia was found. The hypercalcemia resolved when the tumor was treated with chemotherapy. PTHrP levels also decreased with the chemotherapeutic treatment. This is the first report of a patient with a calcitonin-producing islet cell tumor and hypercalcemia mediated by PTHrP.
 ...
PMID:PTHrP-mediated hypercalcemia in a calcitonin-producing islet cell tumor. 1525 89

Calcitonin (CT) was first reported as a hypocalcemic principle, initially thought to originate from the parathyroid gland, a view subsequently corrected to an origin from parafollicular C-cells. Human CT is a 32 amino acid peptide with an N-terminal disulphide bridge and a C-terminal prolineamide residue, shown to potently inhibit bone resorption. More recent studies have demonstrated that this may take place through a direct osteoclastic action. A number of osteoclast CT receptors have subsequently been characterized and particular receptor regions necessary for ligand binding and intracellular signaling identified. Its potent anti-resorptive effect has led to its use in treating Paget's bone disease, osteoporosis, hypercalcaemia and osteogenesis imperfecta. This review summarises some key aspects of its synthesis, structure and its actions at the cellular and molecular levels, and leads on to its therapeutic uses that have emerged since its discovery as well as possibilities for future clinical applications.
 ...
PMID:Calcitonin: physiological actions and clinical applications. 1530 Oct 40

Since Calcitonin (CT) inhibits osteoclastic bone resorption, it has been widely used to treat metabolic bone disorders, such as Paget's disease of bone, malignancy-associated hypercalcemia, and osteoporosis. It is recognized, however, that continuous treatment with CT causes a loss of its inhibitory effects on bone resorption. We and other investigators have studied the mechanism and the results indicated that desensitization to CT was closely associated with the down regulation of the CT receptor (CTR). This down regulation was due not only to internalization of the receptor but also to reduced cell surface receptor concentration through inhibition of de novo CTR synthesis. An essential signal for osteoclast differentiation from its precursor cells, which was termed as ODF, was also found identical to tumor necrosis factor (TNF) related activation induced cytokine (TRANCE) and receptor activator of nuclear factor-kappa B ligand (RANKL). Using soluble RANKL and macrophage colony stimulating factor, we recently studied the mechanisms of the biological responses to CT in cells of human osteoclast lineage. The signaling pathway responsible for CTR down regulation in human osteoclasts is different from that observed in mouse osteoclasts: the activation of protein kinase A pathway is primarily responsible for CTR regulation in mouse osteoclasts, while the activation of protein kinase C was predominant in humans. Treatment with CT reduced concentration of cellular surface CTR and CTR mRNA expression also in human osteoclasts. The reduced specific binding, CTR mRNA levels and CT-sensitive adenylate cyclase responsiveness returned to the control levels by 96h after removal of CT. These results may suggest that intermittent administration of CT would be effective for the treatment of osteoporosis, resulting in reduced desensitization in CT target cells.
 ...
PMID:[Appropriate clinical usage of calcitonin escape phenomenon and intermittent v.s. daily administration of calcitonin]. 1577 28

The two most common causes of hypercalcemia are primary hyperparathyroidism and neoplastic disease. Parathyroidectomy is the only curative intervention for the former condition. In the rare cases of patients with primary hyperparathyroidism who present with clinical symptoms due to their hypercalcemia, pharmacological treatment may be required. Fluid repletion and intravenous (IV) administration of bisphosphonates are recommended in the literature. Calcium receptor agonists (calcimimetic agents) are at the present time only available for use within clinical trials. Cancer patients usually present with symptoms of hypercalcemia. Rapid institution of antihypercalcemic treatment is essential in preventing life-threatening deterioration. Fluid repletion and administration of bisphosphonates are the treatment mainstays in hypercalcemia of malignancy. Five bisphosphonates are currently licensed in Europe for treatment of tumor-associated hypercalcemia: etidronate, clodronate, pamidronate, ibandronate, and zoledronate. In the US, pamidronate and zoledronate are licensed for use in this indication. Bisphosphonates containing nitrogen atoms (e.g. pamidronate, ibandronate, and zoledronate) are more potent than those without (e.g. etidronate, clodronate, and tiludronate). In patients with malignant hypercalcemia, the efficacy of the individual bisphosphonate depends on dose administered and initial serum calcium concentration. At present, pamidronate has been studied in the greatest number of investigations and in the largest number of patients. In the literature, the efficacy of pamidronate in restoring normocalcemia ranges between 40% and 100%, depending on the dose used and baseline serum calcium concentration. More recently, one study reported that pamidronate was inferior to zoledronate. In this study, the duration of response was also longer in the two zoledronate groups (30 and 40 days) than in the pamidronate group (17 days). The most serious adverse events of bisphosphonates concern renal function. Increases in serum creatinine levels have been more frequently reported following treatment of tumor-associated hypercalcemia with etidronate (8%) and clodronate (5%) than with the nitrogen-containing bisphosphonates pamidronate (2%) and ibandronate (1%). The frequency of increases in serum creatinine levels following treatment with zoledronate is difficult to estimate. Administration of the nitrogen-containing bisphosphonates has been associated with transient (usually mild) fever, lymphocytopenia, malaise, and myalgias. These events occur within 36 hours of the first dose and are self-limiting. Hypocalcemia occurs in up to 50% of patients treated with bisphosphonates for hypercalcemia of malignancy, although symptomatic hypocalcemia is rare. The toxicity and low efficacy of plicamycin (mithramycin) mean that use of this agent should be restricted to patients with hypercalcemia of malignancy who fail to respond to IV bisphosphonates. Calcitonin is characterized by good tolerability but poor efficacy in normalizing the serum calcium level. However, a major advantage of calcitonin is the acute onset of the hypocalcemic effect, which contrasts with the delayed but more pronounced effect of bisphosphonates. Combination calcitonin and bisphosphonate treatment may therefore be of value when rapid reduction of serum calcium is warranted. Gallium nitrate may be a valuable treatment for hypercalcemia of malignancy. It is characterized by high efficacy and few adverse events apart from renal toxicity (10% of cases). However, data are very limited and further trials are necessary.
 ...
PMID:Current management strategies for hypercalcemia. 1596 62

Calcitonin is currently used to treat hypercalcemia of many clinical types. However, we encountered a woman who suffered severe hypercalcemia and status epilepticus, both of which developed 8 days after the administration of salmon calcitonin for the treatment of breast cancer. When the patient first presented her serum calcium level was 15.5mg/dl, intact parathyroid hormone level 118 pg/ml, calcitonin <2 pg/ml, magnesium 1.2mg/dl, and phosphate 1mg/dl. Her serum calcium level returned to the reference range within 48 h after correction. At follow-up no hypercalcemia had developed, although the patient had received no further treatment for her breast cancer and multiple metastases were subsequently detected. Her hypercalcemia is ascribed to exogenous calcitonin supplementation. These conflicting events may be due to functionally heterogeneous calcitonin receptors or to activation of 1 alpha-hydroxylase by exogenous calcitonin.
 ...
PMID:Hypercalcemia and status epilepticus relates to salmon calcitonin administration in breast cancer. 1614 33

The chemo-enzymatic synthesis of a glycopeptide, which involves the chemical synthesis of N-acetylglucosaminyl peptide and the enzymatic transfer of oligosaccharide, is described. The first step of the chemo-enzymatic method is the chemical synthesis of N-acetylglucosaminyl peptide with an N-acetylglucosamine moiety bound to the asparaginyl residue of the peptide by a solid-phase method. The second step is transglycosylation of a complex-type oligosaccharide derived from a glycopeptide to an N-acetylglucosaminyl peptide by endo-beta-N-acetylglucosaminidase of Mucor hiemalis (Endo-M). Peptide T can block HIV infection of human T cells. We added the sialo-complex-type oligosaccharide to chemically synthesized N-acetylglucosaminyl Peptide T using the transglycosylation activity of Endo-M. The glycosylated Peptide T thus produced showed a higher degree of resistance to protease digestion than Peptide T. We also prepared calcitonin glycopeptide. Calcitonin is a calcium-regulating hormone that is widely used in therapy for hypercalcemia, and is glycosylated by the chemo-enzymatic method described above. This glycopeptide demonstrated sufficient physiological activity. Comparison of NMR data between native calcitonin and calcitonin glycopetide revealed that the glycosylation does not affect the binding topology of the peptide. N-Acetylglucosaminyl glutamine was also a good glycoside acceptor of Endo-M. We were able to add the sialo-complex-type oligosaccharide to the glutamine residue of the Substance P neuropeptide using the transglycosylation activity of Endo-M. The glycosylated Substance P was biologically active, although its activity was rather low, and stable against peptidase digestion. The oligosaccharide moiety attached to the l-glutamine residue of the peptide was not liberated by PNGase that liberated asparagine-linked oligosaccharide from glycopeptides.
 ...
PMID:Chemo-enzymatic synthesis of bioactive glycopeptide using microbial endoglycosidase. 1623 37

Calcitonin is an endogenous regulator of calcium homeostasis, which acts principally on bone. At present, the principal indications for the therapeutic use of calcitonin are disorders involving hypercalcemia Paget's disease, acute pancreatitis, high-bone-turnover osteoporosis, pain associated with osteoporosis or bone metastases, and Sudeck's atrophy. The aim of this study was to compare the analgesic effects on postoperative pain of salmon calcitonin versus opioids administered epidurally. Our prospective study included 53 ASA I-II patients who were scheduled for total hip arthoplasty under epidural anaesthesia and who did not fulfill 1 or more of the exclusion criteria: a history of pituitary gland dysfunction; diabetes mellitus; obesity; contraindications to performing an epidural block and/or an allergy to calcitonin. These patients were randomly allocated into 3 groups (A, B, and C), each of which received postoperatively a different analgesic epidural mixture of 10 mL to control postoperative pain. Group A was given bupivacaine 0.5% (5 mL) + fentanyl 100 (2 mL) + NaCl 0.9% (3 mL). Group B was given bupivacaine 0.5% (5 mL) + salmon calcitonin 100IU (1 mL) + NaCl 0.9% (4 mL). Group C was given salmon calcitonin 100IU (1 mL) + NaCl 0.9% (9 mL). Perioperatively, 4 blood samples were taken from each patient at the following specific times: 1. Before the induction of anesthesia; 2. At the end of the operation and before the epidural administration of the analgesic mixture; 3. At the end of the first postoperative hour (1 hour after the administration of the analgesic mixture); and 4. At the end of the second postoperative hour (2 hours after the administration of the mixture). In each blood sample, glucose, cortisol, growth hormone, and prolactin plasma levels were determined in order to investigate the changes of these parameters as a result of the endocrine reaction to stress, and to pain relief. The analgesic solution was administered immediately after the second blood sample was taken. At the same time as the 4 blood samples were taken, haemodynamic parameters and pain scores were recorded. Epidural salmon calcitonin in combination with local anaesthetic produces an analgesic effect similar to fentanyl and with stable hemodynamic results. It also eliminates postoperative hyperglycaemia. The cortisol plasma level does not increase during the first postoperative hour, but increases significantly during the second postoperative hour. Growth hormone and prolactin plasma levels were stable in all patients in all 3 groups. This study shows that calcitonin is a suitable alternative for the treatment of acute postoperative pain.
 ...
PMID:Epidural calcitonin: does it provide better postoperative analgesia? An analysis of the haemodynamic, endocrine, and nociceptive responses of salmon calcitonin and opioids in epidural anesthesia for hip arthroplasty surgery. 1715 40


<< Previous 1 2 3 4 5 6 7 8 9 Next >>