Rapid onset of hypercalcemia from high-grade lymphoma in the setting of HIV-related immune reconstitution inflammatory syndrome.

Hypercalcemia in HIV patients has been previously reported, but 1,25-(OH)2 vitamin D-mediated hypercalcemia, due to increased activity of extrarenal 1-alpha hydroxylase, is rarely described with HIV-related infections or malignancies. We describe a case of 1,25-(OH)2 vitamin D-mediated hypercalcemia in a patient presenting with progressive cognitive decline and weakness. Initial evaluation revealed a new diagnosis of HIV, for which he was started on antiretroviral therapy (ART). He was also noted to have mild asymptomatic hypocalcemia, likely from his acute illness and malnutrition, which was not further investigated at the time. While the patient's mental status initially improved with ART, he became progressively delirious and was found to be hypercalcemic approximately 4 weeks after the initiation of ART. Possible etiologies for hypercalcemia were vigorously evaluated, including granulomatous disease, infection, and malignancy, in the setting of suspected immune reconstitution inflammatory syndrome (IRIS), due to recent initiation of ART. Infectious workup was unrevealing, but computed tomography (CT) of the chest, abdomen, and pelvis revealed new extensive diffuse lymphadenopathy and hepatomegaly, not present on admission studies. Cytology and flow cytometry of a liver biopsy specimen revealed CD10 positive high-grade B-cell lymphoma. Chemotherapy was not pursued due to poor performance status. Over the next week, spontaneous tumor lysis developed, and the patient expired. Postmortem, his 1,25-(OH)2 vitamin D level returned as markedly elevated. Immunohistochemical staining of his liver biopsy tissue showed strong expression of CYP27B1. 1,25-(OH)2 vitamin D-mediated hypercalcemia is uncommon in a patient with newly diagnosed HIV and, in this case, was likely due to IRIS unmasking an underlying high-grade lymphoma and restoration of immune function (including T-cells and cytokine production). This case emphasizes the importance of including aggressive lymphomas, capable of progressing over days to weeks, in the evaluation of hypercalcemia in HIV patients at risk for developing IRIS and the rapid dynamic changes in mineral homeostasis that can occur with such an aggressive tumor in an immunocompromised host

Class C Orphans in GtoPdb v.2023.1

This set contains class C 'orphan' G protein coupled receptors where the endogenous ligand(s) is not known

Class C Orphans (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

This set contains class C 'orphan' G protein coupled receptors where the endogenous ligand(s) is not known

Recombinant Human Parathyroid Hormone Effect on Health-Related Quality of Life in Adults With Chronic Hypoparathyroidism

Context: Reduced health-related quality of life (HRQoL) is common in patients with hypoparathyroidism on conventional therapy with calcium and active vitamin D supplements. Objective: To examine the effects of recombinant human parathyroid hormone (rhPTH[1-84]) on HRQoL as measured by the 36-Item Short Form Health Survey (SF-36) during the multinational, randomized, placebo-controlled REPLACE study. Patients: 122 adults with chronic hypoparathyroidism. Intervention(s): Following an optimization period when calcium and/or active vitamin D supplements were adjusted to reach target serum calcium levels (8.0-9.0 mg/dL; 2.0-2.2 mmol/L), patients were randomized to receive placebo (n=39) or rhPTH(1-84) (n=83) (starting dose 50 mug/day, could be titrated up to 100 mug/day); supplement doses were adjusted to maintain target serum calcium levels. Main Outcome Measure(s): Change from baseline (post-optimization, at randomization) to Week 24 in HRQoL as assessed by the SF-36v2 health survey. Results: Overall, the between-group differences were not statistically significant. However, in the rhPTH(1-84) group, there were significant improvements in the physical component summary score (P=0.004) and in body pain (P<0.05), general health (P<0.05), and vitality (P<0.001) domains as compared with baseline values. In the placebo group, there were no significant changes for any of the domains. The magnitude of change between 0 and 24 weeks in SF-36 scores was negatively correlated with baseline scores, such that patients with lower HRQoL at baseline were more likely to experience improvement in response to treatment. Conclusions: Treatment with rhPTH(1-84) may improve HRQoL in adults with hypoparathyroidism

Calcium-sensing receptor (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

The calcium-sensing receptor (CaS, provisional nomenclature as recommended by NC-IUPHAR [44]) responds to multiple endogenous ligands, including extracellular calcium and other divalent/trivalent cations, polyamines and polycationic peptides, L-amino acids (particularly L-Trp and L-Phe), glutathione and various peptide analogues, ionic strength and extracellular pH (reviewed in [74]). While divalent/trivalent cations, polyamines and polycations are CaS receptor agonists [14, 106], L-amino acids, glutamyl peptides, ionic strength and pH are allosteric modulators of agonist function [34, 44, 58, 104, 105]. Indeed, L-amino acids have been identified as "co-agonists", with both concomitant calcium and L-amino acid binding required for full receptor activation [143, 51]. The sensitivity of the CaS receptor to primary agonists is increased by elevated extracellular pH [17] or decreased extracellular ionic strength [105]. This receptor bears no sequence or structural relation to the plant calcium receptor, also called CaS

Calcium-sensing receptor in GtoPdb v.2023.1

The calcium-sensing receptor (CaS, provisional nomenclature as recommended by NC-IUPHAR [47] and subsequently updated [77]) responds to multiple endogenous ligands, including extracellular calcium and other divalent/trivalent cations, polyamines and polycationic peptides, L-amino acids (particularly L-Trp and L-Phe), glutathione and various peptide analogues, ionic strength and extracellular pH (reviewed in [78]). While divalent/trivalent cations, polyamines and polycations are CaS receptor agonists [14, 110], L-amino acids, glutamyl peptides, ionic strength and pH are allosteric modulators of agonist function [36, 47, 61, 108, 109]. Indeed, L-amino acids have been identified as "co-agonists", with both concomitant calcium and L-amino acid binding required for full receptor activation [149, 54]. The sensitivity of the CaS receptor to primary agonists is increased by elevated extracellular pH [18] or decreased extracellular ionic strength [109] while sensitivity is decreased by pathophysiological phosphate concentrations [20]. This receptor bears no sequence or structural relation to the plant calcium receptor, also called CaS

Calcium-sensing receptor in GtoPdb v.2021.3

The calcium-sensing receptor (CaS, provisional nomenclature as recommended by NC-IUPHAR [47] and subsequently updated [77]) responds to multiple endogenous ligands, including extracellular calcium and other divalent/trivalent cations, polyamines and polycationic peptides, L-amino acids (particularly L-Trp and L-Phe), glutathione and various peptide analogues, ionic strength and extracellular pH (reviewed in [78]). While divalent/trivalent cations, polyamines and polycations are CaS receptor agonists [14, 110], L-amino acids, glutamyl peptides, ionic strength and pH are allosteric modulators of agonist function [36, 47, 61, 108, 109]. Indeed, L-amino acids have been identified as "co-agonists", with both concomitant calcium and L-amino acid binding required for full receptor activation [148, 54]. The sensitivity of the CaS receptor to primary agonists is increased by elevated extracellular pH [18] or decreased extracellular ionic strength [109]. This receptor bears no sequence or structural relation to the plant calcium receptor, also called CaS

Calcium-sensing receptor (version 2020.5) in the IUPHAR/BPS Guide to Pharmacology Database

The calcium-sensing receptor (CaS, provisional nomenclature as recommended by NC-IUPHAR [46] and subsequently updated [76]) responds to multiple endogenous ligands, including extracellular calcium and other divalent/trivalent cations, polyamines and polycationic peptides, L-amino acids (particularly L-Trp and L-Phe), glutathione and various peptide analogues, ionic strength and extracellular pH (reviewed in [77]). While divalent/trivalent cations, polyamines and polycations are CaS receptor agonists [14, 109], L-amino acids, glutamyl peptides, ionic strength and pH are allosteric modulators of agonist function [35, 46, 60, 107, 108]. Indeed, L-amino acids have been identified as "co-agonists", with both concomitant calcium and L-amino acid binding required for full receptor activation [147, 53]. The sensitivity of the CaS receptor to primary agonists is increased by elevated extracellular pH [17] or decreased extracellular ionic strength [108]. This receptor bears no sequence or structural relation to the plant calcium receptor, also called CaS