Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Within a recent one-year period, 3 patients in the accelerated phase of chronic myelogenous leukemia were admitted to our medical center with severe hypercalcemia. Simultaneous determinations of ionized calcium and parathyroid hormone levels in 2 of the patients confirmed the hypercalcemia and revealed suppression of parathyroid hormone. We conclude that hypercalcemia in the accelerated phase of chronic myelogeneous leukemia may be more common than previously described and is not mediated by parathyroid hormone. An elevated parathyroid hormone level accompanying hypercalcemia in these patients should suggest the additional diagnosis of primary hyperparathyroidism. Mithramycin was necessary for control in 2 of our cases as well as in others reported in the medical literature and should be an early therapeutic consideration whenever saline diuresis is inadequate.
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PMID:Hypercalcemia in the accelerated phase of chronic myelogenous leukemia. 645 95

Hypercalcaemia complicating acute myelogenous leukaemia is a rare but well-recognized phenomenon. In most cases the pathogenetic mechanism causing the hypercalcaemia remains poorly understood. We recently studied in detail two patients with acute myelogenous leukaemia who developed hypercalcaemia during the course of their illness. The results of these studies conclusively excluded primary hyperparathyroidism or ectopic parathyroid hormone production as causes of the patients' hypercalcaemia. In vitro studies carried out on short-term suspension cultures of one patient's peripheral blood blast cells demonstrated production of a factor with potent bone resorbing activity, distinct from parathyroid hormone (iPTH) and prostaglandin E2 (PGE2). Further characterization of the bone resorbing factor suggested that it bore some similarity to osteoclast activating factor (OAF). Hypercalcaemia in the other case appeared to be due to a combination of skeletal invasion by malignant cells, and to ectopic secretion of an unidentified humoral factor with bone resorbing activity. These two cases demonstrate that the hypercalcaemia complicating acute myelogenous leukaemia may be due to a variety of mechanisms distinct from parathyroid hormone production.
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PMID:Hypercalcaemia complicating acute myelogenous leukaemia: a syndrome of multiple aetiologies. 657 10

Two adults who had T-cell lymphoma-leukemia and recurrent hypercalcemia in the absence of radiographic evidence of bone disease are described. Bone histopathology showed marked osteoclastic activation. Bone resorbing factors, including both prostaglandin E and a material produced in the presence of a prostaglandin synthetase inhibitor, were detected in the in-vitro culture fluids of malignant cells of one of the patients. Serum levels of parathyroid hormone were not elevated. These findings suggest that hypercalcemia resulted from in-vitro osteoclast activation by tumor cell product(s), one of which may be similar, if not identical, to the lymphocyte product osteoclast-activating factor. Two other patients having T-cell lymphoma-leukemia and hypercalcemia have been identified in the literature: the malignant cells of one of these patients also released a calcium-mobilizing factor in vitro.
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PMID:Hypercalcemia associated with T-cell lymphoma-leukemia. 697 May 19

22-Oxacalcitriol (OCT), a synthetic vitamin D3 analog, can mimic the ability of calcitriol to differentiate leukemia and skin cells, to enhance the immune response and to suppress parathyroid hormone secretion, but has much less calcemic activity than that of calcitriol. The mechanism of this selective action remains not fully understood, and the actions of OCT on bone metabolism are little known. The present study was, therefore, designed to investigate the effects of OCT and calcitriol on: the proliferation and functions of osteoblastic MC3T3-E1 cells; osteoclast-like cell formation from hemopoietic blast cells in the absence of stromal cells as well as from unfractionated bone cells in the presence of stromal cells; bone resorption; and the proliferation of MC3T3-E1 cells via monocytes. 22-Oxacalcitriol and calcitriol inhibited [3H]thymidine (TdR) incorporation, alkaline phosphatase activity and collagen synthesis of MC3T3-E1 cells to a similar degree. Both OCT (10(-10)-10(-8) mol/l) and calcitriol significantly and similarly stimulated osteoclast-like cell formation from both hemopoietic blast cells and unfractionated bone cells. 22-Oxacalcitriol (10(-10) and 10(-8) mol/l) significantly stimulated bone resorption, although to a slightly lesser degree than did calcitriol. Human monocyte-conditioned medium (CM) significantly stimulated TdR incorporation into MC3T3-E1 cells. On the other hand, CM obtained from monocytes treated with calcitriol (10(-10)-10(-8) mol/l) significantly inhibited TdR incorporation in a dose-related fashion, whereas CM obtained from monocytes treated with OCT (10(-10)-10(-8) mol/l) significantly stimulated TdR incorporation in a dose-related fashion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of 22-oxacalcitriol on bone metabolism in vitro: comparison with calcitriol--effects of 22-oxacalcitriol on osteoclast-like cell formation and bone-resorbing activity. 758 94

Hypercalcemia in adult T-cell leukemia has been attributed to increased levels of 1,25-dihydroxyvitamin D (1,25(OH)2D), whereas in other types of leukemia, hypercalcemia has been blamed on direct skeletal invasion by malignant cells, ectopic parathyroid hormone (PTH) production or bone-resorbing cytokines. A 51-year-old man was studied who presented with back pain, circulating myeloblasts, and hypercalcemia. The bone marrow revealed acute myeloblastic leukemia. While the ionized calcium concentration was 8.17 mg/dL (normal, 4.73 to 5.21 mg/dL), the levels of PTH, PTH-related peptide, vitamin D, and thyroxine were normal or subnormal. Bone histomorphometry showed a decreased cortical width with intracortical erosion cavities dissecting into the marrow space. In cancellous bone, the osteoid area, osteoblast perimeter, and tetracycline fluorescence were sparse, whereas the osteoclast perimeter was increased. Persistent marrow fat, the general absence of trabecular narrowing, and the prompt response to calcitonin suggest that the osteoclasts caused the hypercalcemia and lytic lesions, rather than pressure atrophy or osteolysis by leukemic infiltration. Osteoclast activation and subsequent hypercalcemia may have been due to a locally produced cytokine, such as interleukin-1 beta or tumor necrosis factor.
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PMID:Case report: hypercalcemia in acute myeloblastic leukemia is caused by osteoclast activation. 812 79

A retrospective study of 26 adults with acute T-cell leukemia showed that 14 patients (54%) had hypercalcemia at some point of the disease. Hypercalcemia was found at presentation in nine patients and revealed the disease in one. Eight patients had hypercalcemia at the time of death. Serum phosphorus and parathyroid hormone levels were normal. All patients with hypercalcemia tested positive for the HTLV-1 by Elisa and Western blot. Six patients had focalized or diffuse lytic roentgenographic bone lesions. Hypercalcemia in acute T-cell leukemia may involve production of interleukin-1-alpha and parathyroid hormone-related protein by HTLV-1-infected cells.
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PMID:[Hypercalcemia of T-cell leukemia in adults]. 816 27

Human T-cell leukemia virus type I (HTLV-I) is the etiologic agent of adult T-cell leukemia (ATL), and hypercalcemia frequently associated with ATL is mediated by parathyroid hormone-related peptide (PTHRP). The present study was undertaken to clarify the role of cAMP second messenger system in the regulation of human PTHRP gene expression in ATL cells, using an HTLV-I-infected T-cell line, MT-2. Forskolin and dibutyryl cAMP (Bt2cAMP) caused a marked and transient increase in the steady-state level of PTHRP mRNA. The effects of these agents were dose-dependent, and the maximal effects were observed at 3 h. Nuclear runoff transcription assay showed that forskolin and Bt2cAMP caused an increase in the transcription rate of the human PTHRP gene. In contrast, the stability of PTHRP mRNA was only modestly increased by these agents. Forskolin and Bt2cAMP also increased the secretion of PTHRP by MT-2 cells, as determined by both a newly established immunoradiometric assay using two antibodies against human PTHRP-(1-34) and PTHRP-(50-83) and a radioimmunoassay using an antibody against human PTHRP-(109-141). Prostaglandin E1 (PGE1) caused a marked stimulation of intracellular cAMP production in MT-2 cells, whereas PGE2 and PGF2 alpha had only modest effects. The ability of these PGs to stimulate cAMP production correlated well with their ability to increase PTHRP mRNA level and the secretion of PTHRP. Indomethacin did not affect the basal level of cAMP production or PTHRP mRNA, suggesting that endogenous PG was not involved in the basal production of cAMP or PTHRP. When PGE1 was given to MT-2 cells together with interleukin 2, which is another stimulator of PTHRP gene expression, PTHRP secretion was synergistically stimulated. These results suggest that the transcription of the human PTHRP gene is enhanced through a cAMP-dependent pathway by PGE1 and that PGE1, as well as interleukin 2, plays an important role in the overexpression of the human PTHRP gene in HTLV-I-infected T cells leading to the development of hypercalcemia in ATL patients.
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PMID:Transcription of the gene for parathyroid hormone-related peptide from the human is activated through a cAMP-dependent pathway by prostaglandin E1 in HTLV-I-infected T cells. 838 Apr 5

A human acute lymphoblastic leukemia (ALL) cell line, BALM-16, was established from the peripheral blood specimen of a patient with B cell ALL L3 type (ALL-L3) in relapse. As with the original leukemia cells, the established line was negative for both cell surface and cytoplasmic immunoglobulin (Ig) chains. Absence of Ig expression was confirmed by Western blotting. Southern blot analysis demonstrated homozygous deletion of the C kappa gene, germ line configuration of the C lambda and rearrangement of IgJH genes. Cytogenetic analysis of both leukemic bone marrow and BALM-16 cells showed the t(8;22)(q24;q11) abnormality which is specifically associated with ALL-L3 and Burkitt lymphoma. The patient's serum showed hypercalcemia, prompting further investigation of the established cell lines which showed parathyroid hormone-related peptide (PTHrP) mRNA detected by reverse-transcriptase polymerase chain reaction. However, PTHrP production was not detected in the culture supernatant. The established cell line, BALM-16, could provide a useful material for analyzing the lack of Ig expression and of clarifying the pathogenesis of this type of B cell malignancy.
Leukemia 1997 Dec
PMID:A novel ALL-L3 cell line, BALM-16, lacking expression of immunoglobulin chains derived from a patient with hypercalcemia. 944 37

While there is considerable evidence for phosphate (Pi) reabsorption in the distal tubule, Pi transport and its regulation have not been well characterized in this segment of the nephron. In the present study, we examined Na+-dependent Pi transport in immortalized mouse distal convoluted tubule (MDCT) cells. Pi uptake by MDCT cells is Na+-dependent and, under initial rate conditions, is inhibited by phosphonoformic acid (41 +/- 3% of control), a competitive inhibitor of Na+-Pi cotransport. The transport system has a high affinity for Pi (Km = 0.46 mM) and is stimulated by lowering the extracellular pH from 7.4 to 6.4 and inhibited by raising the pH from 7.4 to 8.4. Exposure to Pi-free medium for 21 h increased Na+-Pi cotransport from 2.1 to 5.5 nmol/mg of protein/5 minutes (p < 0.05) while parathyroid hormone, forskolin, and phorbol 12-myristate 13-acetate failed to alter Pi uptake in MDCT cells. Reverse transcriptase polymerase chain reaction of MDCT cell RNA provided evidence for the expression of the Npt1 but not the Npt2 Na+-Pi cotransporter gene. However, preincubation of MDCT cells with Npt1 antisense oligonucleotide led to only 20% inhibition of Na+-Pi cotransport, suggesting that other Na+-Pi cotransporters are operative in MDCT cells. Indeed, we showed, by ribonuclease protection assay, that MDCT cells express the ubiquitous cell surface receptors for gibbon ape leukemia virus (Glvr-1) and amphoteric murine retrovirus (Ram-1) that also function as Na+-Pi cotransporters. In summary, we demonstrate that the pH dependence and regulation of Na+-Pi cotransport in MDCT cells is distinct from that in the proximal tubule and suggest that different gene products mediate Na+-Pi cotransport in the proximal and distal segments of the nephron.
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PMID:Na+ -phosphate cotransport in mouse distal convoluted tubule cells: evidence for Glvr-1 and Ram-1 gene expression. 955 59

A patient with an intermediate state of human T lymphotropic virus type I (HTLV-I) infection and in whom autopsy showed multiple organ failure (MOF) associated with extensive metastatic calcification in systemic organs is described. A 56-year-old man presented with signs and symptoms of advanced cardiac insufficiency, respiratory disturbance and renal failure. Serologically, the anti-human T lymphotropic virus type I (HTLV-I) antibody titer and the levels of both calcium and parathyroid hormone-related peptide (PTHrP) were distinctly elevated. These data suggested a diagnosis of adult T cell lymphoma/leukemia (ATLL). However, examination of a peripheral blood sample revealed only a few atypical lymphoid cells (3%) associated with mild leukocytosis (white blood cell count, 13.7 x 10(3)/mm3). Lymph node swelling was systemic but mild, with some nodes up to 10 mm in diameter. The patient died of MOF. Adult T cell leukemia/lymphoma was unable to be diagnosed definitively because of the short duration of laboratory abnormalities and because of the discrepancy between the laboratory data and the magnitude of lymphoproliferation in both the lymph nodes and peripheral blood. At autopsy, the most conspicuous finding was extensive metastatic calcification in the multiple organs, including the heart, lungs, kidneys, tongue, liver, pancreas, spleen and systemic arterial walls. Very small numbers of medium-sized atypical lymphoid cells admixed with small reactive lymphocytes were identified in multiple organs, with no evidence of massive infiltration. Molecular analyses could not detect monoclonal integration of HTLV-I provirus DNA or monoclonality of T cell lineage cells. Parathyroid hormone-related peptide was demonstrated in the cytoplasm of the atypical lymphoid cells on immunohistochemical examination. The bone trabeculae generally showed distinct evidence of resorption associated with marked proliferation of osteoclasts. These findings suggested that the hypercalcemia in the present case was categorized as humoral hypercalcemia of malignancy rather than local osteolytic hypercalcemia.
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PMID:Multiple organ failure associated with extensive metastatic calcification in a patient with an intermediate state of human T lymphotropic virus type I (HTLV-I) infection: report of an autopsy case. 964 62


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