Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:7440-70-2 (calcium)
 333,191 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Differentiating between primary and ectopic or pseudohyperparathyroidism may be difficllt, but certain aspects of the patient's clinical history as well as laboratory tests may be helpful. We present an unusual case report of a patient who had massive splenomegaly secondary to a localized histiocytic lymphoma. On the basis of a lower serum parathormone level for a given serum calcium increase combined with normal serum phosphorous and chloride values, the diagnosis of psuedohyperparathyroidism was made and was confirmed when the patient's serum calcium level and temperature returned to normal following splenectomy.
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PMID:Isolated histiocytic lymphoma of the spleen causing fever and hypercalcemia. 33 15

Two closely related Ca(2+)-binding proteins, migration inhibitory factor-related protein (MRP)-8 and MRP-14, are synthesized under specific conditions of myeloid cell differentiation. Because 1 alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] induces myeloid cell differentiation and expression of other S-100 class calcium-binding proteins, we examined the effects of 1,25-(OH)2D3 on MRP mRNA levels in human U-937 histiocytic lymphoma cells. 1,25-(OH)2D3 increased MRP-8 and MRP-14 mRNA levels in a time- and dose-dependent manner. MRP mRNA levels were maximal at 24 h and remained elevated for at least 96 h after exposure of the cells to 1,25-(OH)2D3. MRP-8 mRNA accumulation required 100- to 1,000-fold higher concentrations of 25-(OH)D3, which binds to the 1,25-(OH)2D3 intracellular receptor with 100- to 1,000-fold lower affinity. Other differentiating agents, dimethyl sulfoxide, retinoic acid, and dexamethasone, also increased levels of MRP-8 and MRP-14 mRNA. Phorbol myristate acetate enhanced MRP-14 mRNA levels to a greater extent than MRP-8 mRNA levels, suggesting differential regulation of MRP gene expression by protein kinase C. The 1,25-(OH)2D3-induced relative increase in MRP mRNA levels was not changed by a 1,000-fold reduction in extracellular [Ca2+]. Thus 1,25-(OH)2D3 is potentially a physiological modulator of MRP gene expression. Expression of the MRP-8 and MRP-14 genes may be important for differentiation of myeloid cells.
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PMID:1 alpha,25-(OH)2 vitamin D3 enhances expression of the genes encoding Ca(2+)-binding proteins MRP-8 and MRP-14. 173 33

Calcipotriol (MC 903) is a novel analogue of the physiologically active metabolite of vitamin D3, 1 alpha,25-dihydroxycholecalciferol [1,25(OH)2D3]. MC 903 and 1,25(OH)2D3 have similar effects on cell proliferation and cell differentiation in vitro using the human histiocytic lymphoma cell line U 937, but in vivo MC903 has 100-200 times less effect on calcium metabolism. To elucidate this difference, the pharmacokinetic profiles after a single intravenous dose (50 micrograms/kg) of the two compounds to rats were compared. The area under the serum level/time curve (AUC) was more than 100 times higher for 1,25(OH)2D3 than for MC903 and the rate of clearance was more than 100 times higher for MC903 than for 1,25(OH)D3. Serum from MC903 or 1,25(OH)2D3 dosed rats (i.v. 10 micrograms/kg) was investigated for biological activities by incubation of U 937 cells with serum collected 0-24 hr after drug administration. Serum from MC903 dosed rats had an effect only when collected shortly after dosing, whereas serum from 1,25(OH)2D3 dosed rats had an effect when collected up to 4 hr after dosing. The biological effects on the U937 cells of the two major metabolites of MC903 (MC 1046 and MC 1080) were investigated. The metabolites had effects that were more than 100 times weaker than those of the parent compound. The effect of MC903 on proliferative disorders, its fast elimination and the formation of inactive metabolites makes MC903 suitable for topical treatment of psoriasis.
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PMID:Calcipotriol (MC 903): pharmacokinetics in rats and biological activities of metabolites. A comparative study with 1,25(OH)2D3. 204 50

Interleukin (IL) 1 alpha is synthesized as a 33-kDa precursor that is enzymatically cleaved to the 15-17-kDa forms that are found in the culture supernatants of activated macrophages. We have explored the possibility that calcium might enhance IL-1 processing and secretion via the stimulation of a calcium-dependent protease. We have found that lysates prepared from human peripheral blood monocytes, the human histiocytic lymphoma cell line U937, and the murine macrophage cell line P388D1 contain a calcium-dependent IL-1 alpha processing activity that cleaves the IL-1 alpha precursor to its mature form. Although NIH 3T3 mouse fibroblast cell lysates also contain IL-1 processing activity, lysates from the murine thymoma EL-4, the human epidermoid cell line HEp-2, and the human foreskin fibroblast line FS-4 lack this activity. IL-1 processing activity is inhibited by leupeptin and exhibits a molecular mass of 80-110 kDa. The processing activity is also inhibited by a monoclonal antibody directed against calpain type I. These results indicate that the processing of the IL-1 alpha precursor is mediated, at least in part, by a member of the calpain family of proteases. Mixing experiments revealed that lysates from EL-4 or HEp-2 cells contain an inhibitor(s) of the calpain-like protease in macrophage extracts. It is, therefore, likely that many non-macrophage cell types are unable to process the IL-1 alpha precursor because the calpain present in these cells is only weakly active due to the presence of a specific inhibitor(s) such as calpastatin.
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PMID:Involvement of a calpain-like protease in the processing of the murine interleukin 1 alpha precursor. 206 4

MC 903 is a novel vitamin D analogue which has been tested for its effects on cell differentiation and cell proliferation in vitro using the human histiocytic lymphoma cell line U937, and on calcium metabolism in rats in vivo. In the present investigation MC 903 was compared to the natural metabolite of vitamin D3, 1 alpha,25-dihydroxycholecalciferol [1,25(OH)2D3] and to its synthetic analogue 1 alpha-hydroxycholecalciferol [1 alpha (OH)D3]. MC 903 was found to be a potent inducer of cell differentiation and to inhibit cell proliferation and DNA-synthesis in concentrations comparable to those observed with 1,25(OH)2D3. 1 alpha (OH)D3, which is only active after metabolic conversion to 1,25(OH)2D3, was more than 100 times less potent. Oral or intraperitoneal administration of MC 903 to rats showed that the compound was at least 100 times less active than 1,25(OH)2D3 and 1 alpha (OH)D3 in causing hypercalciuria, hypercalcemia and bone calcium mobilisation. The low vitamin D activity of MC 903 was further confirmed by administration of the compound to rachitic rats. The strong direct effects of MC 903 on cell proliferation and cell differentiation, coupled with its decreased activity as a classical vitamin D makes this compound an interesting candidate for studies in human proliferative disorders such as psoriasis.
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PMID:Effects of a novel vitamin D analogue MC903 on cell proliferation and differentiation in vitro and on calcium metabolism in vivo. 283 Aug 85

There is a paucity of information regarding the natural history and treatment outcome of diffuse histiocytic lymphoma (DHL) in Australia. Case records from 80 patients treated for DHL at the Royal Adelaide Hospital between 1965 and 1985 were reviewed to determine treatment outcome and prognostic information. Pathological review of biopsy specimens confirmed the correct diagnosis in 78 patients. The Ann Arbor staging criteria were unsatisfactory for prognostic purposes. We identified three prognostic groups: Localised disease (82% five-year survival), Advanced disease marrow negative (36% five-year survival), and Advanced disease marrow positive (11% five-year survival). An elevated plasma lactate dehydrogenase (LDH) and calcium (Ca++) predicted a poorer outcome; no patient with a LDH greater than 500 IU achieved longterm survival (p less than 0.001). Survival was identical for patients reclassified histologically as intermediate grade or high grade (Working Formulation). Localised disease was associated with a good prognosis (82% five-year survival) regardless of treatment modality. The outcome of patients with advanced disease has markedly improved over the last two decades, particularly with the introduction of combination chemotherapy containing doxorubicin in 1974 (p less than 0.005). Using these regimens, complete remission was achieved in 65% of patients, with a 39% five-year survival.
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PMID:Diffuse histiocytic lymphoma: the 20-year experience of an Australian teaching hospital. 269 13

Seventy-eight individuals previously treated with chemotherapy for non-Hodgkin's lymphoma were enrolled in a phase II pilot study employing methotrexate 100 mg/M2 iv (day 1), calcium leucovorin 10 mg/M2 iv and/or po q6h (days 2-4), VM-26 (teniposide) 100 mg/M2 iv (days 2 and 9), procarbazine 100 mg/M2 po (days 2-15), and dexamethasone 15 mg/M2po (days 2-8) (MV26PD). Thirty percent of the 78 patients treated had a response to therapy (8% complete, 22% partial). Twenty-four percent of patients with diffuse histiocytic (large cell) lymphoma had a response (12% complete, 12% partial). The estimated failure-free survival was 41% at 3 months and the median survival (death from any cause) was 4.5 months for the entire cohort. Two individuals, including one individual with diffuse histiocytic lymphoma, remain in a complete response for over 900 days. Significant hematologic toxicity and infectious complications were seen in this heavily pretreated group of patients. MV26PD represents an active combination of agents for the treatment of non-Hodgkin's lymphoma. The optimal dosing for MV26PD remains to be determined.
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PMID:Treatment of refractory lymphoma with methotrexate, VM-26 (teniposide), procarbazine, and dexamethasone: Cancer and Leukemia Group B study 7902. 326 79

Human histiocytic lymphoma cells (U-937) undergo similar differentiation when incubated with the phorbol ester 12-0-tetradecanoyl phorbol-13-acetate (TPA) and 1,25-dihydroxycholecalciferol. In this action, TPA somehow implicates calcium-sensitive and phospholipid-dependent protein kinase (protein kinase C), which is rapidly and significantly affected by this inducer. On the contrary, 1,25-dihydroxycholecalciferol in its differentiating action does not involve protein kinase C thus suggesting that the secosteroid induces monocytic differentiation possible through a different mechanism of that of phorbol ester.
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PMID:Phorbol esters, but not the hormonal form of vitamin D, induce changes in protein kinase C during differentiation of human histiocytic lymphoma cell line (U-937). 329 40

Some clones of the human histiocytic lymphoma line, U-937, were induced to differentiate into monocyte-like cells with loss of plating efficiency in agar by incubation with 0.1 to 10 nM 1 alpha,25-dihydroxycholecalciferol [1,25(OH)2D3]. At 1 nM, 40% of the cells of one sensitive clone exhibited differentiation after 2 days of incubation judging from assays for phagocytosis and capacity to reduce nitroblue tetrazolium. Induction appeared to occur by binding of the cholecalciferol to a specific cytoplasmic and/or nuclear receptor for 1,25(OH)2D3. However, the presence of this receptor was not sufficient for differentiation, since one clone which contained the receptor did not respond with differentiation upon addition of 1,25(OH)2D3. Differentiation induction did not require DNA synthesis but was blocked by agents which inhibit RNA or protein synthesis. It was also blocked by the calcium ionophore A 23187. A synergistic inducing effect was seen between 1,25(OH)2D3 and retinoic acid. In addition, the U-937 cells could be primed by a short incubation with 1,25(OH)2D3 to respond, with maturation, to the addition of agents which increase the intracellular level of cyclic adenosine 3':5'-monophosphate, such as prostaglandin E2, cholera toxin, and N6,O2'-dibutyryl adenosine 3':5'-monophosphate and which alone did not induce differentiation. Priming does not depend on the normal rate of RNA or protein synthesis, since it was not significantly inhibited by actinomycin D, cordycepin, or cycloheximide. It remains to be determined if unoccupied receptors for 1,25(OH)2D3 are present in fresh leukemia cells and if such cells can sometimes be induced to differentiate upon addition of cholecalciferol.
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PMID:Induction of differentiation of the human histiocytic lymphoma cell line U-937 by 1 alpha,25-dihydroxycholecalciferol. 631 18

In this study, the recently identified human protein kinase C-theta (PKC-theta) isoform has been biochemically characterized in detail. An antiserum raised against the unique V3 domain of PKC-theta identified an 80-kDa protein in all human T-cell lines tested, in erythroleukemia K562 cells and in histiocytic lymphoma U-937 cells, but not in a B-lymphoma line (Raji) or in several melanoma, carcinoma, schwanoma or astrocytoma lines, confirming, at the protein level, its predominant expression in hematopoietic cell lines, in particular T cells. Immunoreactive PKC-theta was detected almost exclusively in the cytosolic compartment of unstimulated Jurkat T cells. Stimulation with phorbol ester, however, caused rapid translocation to the membrane. In order to compare the properties of PKC-theta with a representative member of the Ca(2+)-dependent PKC enzymes, full-length cDNAs encoding PKC-theta or PKC-alpha were transiently expressed in COS-1 cells, and recombinant enzymes were partially purified via a six-histidine peptide tag. The catalytic activity of these PKC enzymes was assayed against distinct substrates in the absence and presence of known PKC cofactors. Significant differences were found with respect to activation requirements and substrate preferences between PKC-theta and PKC-alpha. Both enzymes were stimulated by phospholipid and phorbol ester, and were active towards a PKC-derived substrate peptide corresponding to the pseudosubstrate site of PKC. In contrast to PKC-alpha, however, full activation of PKC-theta did not require Ca2+, and its basal activity towards histone H1 was not stimulated by lipid cofactors. Additionally, a myelin-basic-protein-(MBP)-derived peptide, which was readily phosphorylated by PKC-alpha, was a poor substrate for PKC-theta. Similar to PKC-alpha, transient PKC-theta overexpression in murine EL4 thymoma cells caused an approximately 2.5-fold increase in the phorbol-12-myristate-13-acetate-induced transcriptional activation of an interleukin-2 promoter-reporter gene construct. The unique expression and functional properties of PKC-theta suggest that it may play a specialized role in T-cell signaling pathways.
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PMID:Expression and biochemical characterization of human protein kinase C-theta. 792 38


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