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Results for “MYELOMA, PLASMA CELL”

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At least 19 recordsLinked to original sources
PubMed1977

Growth kinetics of plasma cell myeloma.

The plasma cell labeling index(ex) (LI) of 128 patients with multiple myeloma at various stages of disease was compared as a function of tumor mass load and length of treatment. No significant differences in LI were noted for patients with various degrees of tumor reduction. Patients observed during the first 3 months of treatment had significantly higher LI than did untreated patients and those studied after longer intervals. In vivo cell-cycle analysis of myeloma cells by the halving time of the grain-count method failed to establish the length of the cell cycle but defined the length of S+G2 phases as being longer than 60 hours. Similar studies conducted in vitro defined a shorter combined length of S+G2 phase. In 2 patients in whom continuous infusion with [3H] thymidine was performed, the generation time was established as 8 days. Both patients had similar initial LI (5.7 and 6.6) but different growth fractions (19 and 47%). The measured tumor mass doubling time was much longer than the calculated one, suggesting the presence of considerable intrinsic cell loss (83 and 47%). These observations were summarized by a hypothetical two-compartment model for the growth kinetics of multiple myeloma.

Bone Marrow↗
PubMed2004

Cell proliferation of myeloma plasma cells: comparison of the blood and marrow compartments.

The plasma cell labeling Index (PCLI), a measure of marrow plasma cells in S phase of the cell cycle, provides a good estimate of the proliferative capacity of the malignant clonal plasma cells. Multiple studies have also demonstrated its prognostic value in multiple myeloma (MM). Clonal plasma cells have been demonstrated in the peripheral blood of patients with multiple myeloma. The labeling index of these circulating cells can also be determined by a method similar to that employed for marrow plasma cells. The goal of this study was to compare the proliferation kinetics of plasma cells in the marrow to that in the circulation. The PCLI was estimated on peripheral blood (PBLI) and bone marrow aspirates (BMLI) using a slide-based bromodeoxyuridine (BrdU) immunofluorescence microscopy technique. One hundred seventeen patients who had simultaneous estimation of the PBLI and BMLI and who had > or =90% of the blood cIg+ cells identified as monoclonal plasma cells were studied. The PBLI was generally lower than the BMLI (median difference 0.4) and correlated with the BMLI (rho = 0.491, P < 0.0001). Twenty-seven patients with PBLI higher than BMLI had a poorer prognosis, with median survival of 2 months from the time of the labeling index determination, compared to 12 months for the remaining 90 patients (P = 0.01). Myeloma plasma cells circulating in the peripheral blood are capable of proliferation, albeit at a slower rate compared to those in the marrow. These differences reflect a more favorable microenvironment in the marrow likely resulting from the differences in the cytokine levels and supporting stromal cells in the marrow.

Adult↗
PubMed2005

Wnts induce migration and invasion of myeloma plasma cells.

Multiple myeloma is an incurable form of lymphoid cancer characterized by accumulation of neoplastic plasma cells in the bone marrow cavity. Little is known about the mechanisms regulating myeloma cell movement within the bone marrow and metastasis to secondary sites. Herein, we identify multiple members of the wingless/int (Wnt) family as promoters of myeloma cell migration/invasion. Wnt-mediated migration was associated with the Wnt/RhoA pathway and did not necessitate signaling through beta-catenin. Activation of both RhoA and members of the protein kinase C (PKC) family, including PKCalpha, PKCbeta, and PKCmu, were required for induction of migration. Activated RhoA and PKCalpha, PKCbeta, and PKCmu appear to assemble in macromolecular signaling complexes that are associated with the cell membrane. These results suggest that Wnt responsiveness of myeloma plasma cells may be a significant factor in disease progression.

Cell Line, Tumor↗
PubMed1979

The laboratory diagnosis of plasma cell myeloma and related disorders.

Plasma cell myeloma constitutes the commonest primary malignant tumor affecting the skeleton of the adult. It is also one of several forms of monoclonal gammopathy that include Waldenström's macroglobulinemia, the heavy chain diseases, "benign" (nonprogressive, asymptomatic) monoclonal gammopathy, and primary amyloidosis. The diagnosis of classic or advanced myeloma rests on the findings of sheets of plasmacytic cells in a bone marrow biopsy sample or aspirate; a serum monoclonal immunoglobulin usually of the IgG or IgA class or Bence Jones protein in the urine; and evidence of multiple lytic lesions in x-ray views of the skeleton. Pitfalls in the diagnosis of earlier or unusual forms of myeloma require a careful application of classic diagnostic criteria or of criteria established by clinical cooperative groups.

Bence Jones Protein↗
PubMed2006

Four-color flow cytometric analysis of myeloma plasma cells.

We monitored the behavior of residual myeloma plasma cells in patients with multiple myeloma after high-dose therapy and autologous or allogeneic transplantation using 3 methods of a flow cytometric technique using 4-color staining, immunofixation, and polymerase chain reaction approaches. We analyzed 17 cases by a relatively simple flow cytometric technique using CD38/CD45/CD19/CD56. Detectable myeloma plasma cells were found in 5 patients at diagnosis and 9 patients after treatment. Of 14 cases, 9 (64%) had CD19-CD56+ myeloma plasma cells, and 5 (36%) of 14 had CD19-CD56- myeloma plasma cells. When 37 bone marrow samples that had less than 5% myeloma plasma cells were assessed, myeloma plasma cells were detected in all 20 immunofixation-positive cases and 3 of 17 immunofixation-negative cases (P = .002). All 4 polymerase chain reaction-negative samples characterized as immunofixation-negative contained no detectable myeloma plasma cells. Flow cytometry can provide effective information to detect low levels of myeloma plasma cells.

Adult↗
PubMed1975

Intranuclear inclusions in Bence Jones lambda plasma cell myeloma.

A patient with plasma cell myeloma producing only Bence Jones lambda protein was found to have pale intranuclear inclusions in the majority of the bone marrow plasma cells. These inclusions, previously undescribed in myeloma patients producing only Bence Jones protein, contained Bence Jones lambda protein, were non-electron dense, bound by a single membrane, and contained no cytoplasmic structures. Intracytoplasmic inclusions were not present, and the perinuclear cistern was not dilated. Thus, the inclusions may represent intranuclear protein synthesis with anomalous release in the abnormal cells.

Bence Jones Protein↗
PubMed2002

The cholesterol lowering drug lovastatin induces cell death in myeloma plasma cells.

Lovastatin is an irreversible inhibitor of HMG-CoA reductase and blocks the production of mevalonate, a critical compound in the production of cholesterol and isoprenoids. Isoprenylation of target proteins, like the GTP-binding protein Ras, is essential for their membrane localization and subsequent participation in intracellular signaling cascades. Lovastatin effectively decreased the viability of plasma cells from cell lines (n = 10) and myeloma patients' samples (n = 8) in a dose- and time-dependent way. Importantly, co-incubation of lovastatin with dexamethasone had a synergistic effect in inducing plasma cell cytotoxity. This effect was not the consequence of a change in the protein expression levels of Bcl-2 or Bax induced by lovastatin. The decrease in plasma cell viability was the result of induction of apoptosis and inhibition of proliferation. Mevalonate effectively reversed the cytotoxic and cytostatic effects of lovastatin in plasma cells. The cytotoxic activity of lovastatin was higher in Pgp expressing cell lines, but did not correlate with the multidrug resistance (MDR)-related proteins LRP, Bcl-2 and Bax. Lovastatin treatment resulted in a shift of Ras localization from the membrane to the cytosol that was reversed by mevalonate. The data presented in this paper warrant study of lovastatin alone or in combination with therapeutic drugs, in the treatment of myeloma patients.

Anticholesteremic Agents↗
PubMed1991

Plasma cell myeloma: biology and treatment.

Plasma cell myeloma results from malignant transformation in an early hemopoietic precursor cell. The disease progresses from an asymptomatic stable phase through a symptomatic phase to a terminal acute phase marked by aggressive cell growth and marrow failure. The activation of a series of oncogenes may govern the initiation and stepwise progression of these neoplasms. Chemotherapy causes the tumor to regress in about 50% of patients and improves survival, but it does not alter the course of the disease. Interferon maintenance therapy prolongs remission durations and appears to alter the course of the disease.

Cell Transformation, Neoplastic↗