Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0005940 (bone disease)
 7,459 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple myeloma (MM) originates from the malignant clonal expansion of transformed B-lymphocytes (in which c-myc and ras oncogenes are probably involved). MM cells have a hybrid phenotype (with coexpression of the markers for both early and late B-differentiation and, sometimes, of T-lymphocyte, myelomonocyte, erythroid and megakaryocyte markers), which accounts for the association between MM and myeloproliferative disorders and for cytokine production. Interleukin-6 and immunologic control mechanisms regulate proliferation and differentiation into plasma cells secreting a monoclonal component (MC). Overt MM is diagnosed 1-2 years following malignant transformation. At this time, several aneuploid clones with resistant phenotype have been selected, and a small pool of actively cycling cells produces the great bulk (over 90%) of non proliferating tumor cells. The clinical and laboratory signs of MM arise from both tumor proliferation and MC damage to organs and organ systems. Tumor proliferation is mainly responsible for bone disease (since MM cells produce cytokines that activate the osteoclasts), inhibition of hemopoiesis and the appearance of plasma cell tumors. The MC causes renal failure, neurological signs, hemorrhagic manifestations. The prognosis for multiple myeloma is probably best estimated by two parameters, serum beta-2-microglobulin and the bone marrow labeling index. Induction therapy is still based on the use of alkylating agents, melphalan and cyclophosphamide, combined with prednisone. Second line treatment consists of VAD polychemotherapy or high-dose pulsed glucocorticoids. Many investigational approaches have been proposed, but their effectiveness awaits confirmation. In the absence of a curative regimen, much effort should be dedicated to the quality of supportive care. In this respect, bisphosphonates represent a new effective tool for the control of myeloma bone disease.
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PMID:Multiple myeloma. 208 Oct 91

Individuals with neurofibromatosis type 1 (NF1) have a high incidence of osteoporosis and osteopenia. However, understanding of the cellular and molecular basis of these sequelae is incomplete. Osteoclasts are specialized myeloid cells that are the principal bone-resorbing cells of the skeleton. We found that Nf1(+/-) mice contain elevated numbers of multinucleated osteoclasts. Both osteoclasts and osteoclast progenitors from Nf1(+/-) mice were hyperresponsive to limiting concentrations of M-CSF and receptor activator of NF-kappaB ligand (RANKL) levels. M-CSF-stimulated p21(ras)-GTP and Akt phosphorylation was elevated in Nf1(+/-) osteoclasts associated with gains of function in survival, proliferation, migration, adhesion, and lytic activity. These gains of function are associated with more severe bone loss following ovariectomy as compared with that in syngeneic WT mice. Intercrossing Nf1(+/-) mice and mice deficient in class 1(A) PI3K (p85alpha) restored elevated PI3K activity and Nf1(+/-) osteoclast functions to WT levels. Furthermore, in vitro-differentiated osteoclasts from NF1 patients also displayed elevated Ras/PI3K activity and increased lytic activity analogous to those in murine Nf1(+/-) osteoclasts. Collectively, our results identify a what we believe to be a novel cellular and biochemical NF1-haploinsufficient phenotype in osteoclasts that has potential implications for the pathogenesis of NF1 bone disease.
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PMID:Hyperactivation of p21ras and PI3K cooperate to alter murine and human neurofibromatosis type 1-haploinsufficient osteoclast functions. 1705 31