Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors describe a method of obtaining monospecific serum against secretory IgA and the corresponding standard. An immunochemically pure (11.6S) secretory human IgA was extracted from the colostrum by salt fractionation and gel-filtration through Sephadex G-200 and Sepharose 6B; this IgA was used as an antigen for the immunization and the standard for the quantitative determination of SIgA in the secretions. Monospecific anti-SC-serum was obtained by successive exhaustion of the antiserum against the S IgA immunosorbents prepared from normal human serum and the serum of a patient suffering from A myeloma containing polymeric IgA forms.
 ...
PMID:[Production of monospecific serum against secretory IgA (anti-SC) and a standard for quantitative analysis]. 108 97

The growth curve of monolayer cultures of ARH-77 cells, a human myeloma cell line propagated in vitro, is represented by an everbending curve on a semilogarithmic plot; however, the curve can be fitted by a straight line on a linear-linear plot. This unusual growth pattern suggests that, instead of a fixed proportion of the population, a fixed number of ARH-77 cells divide per unit time. The following are cell cycle transit time parameters calculated from percent labeled mitosis experiments: TG1, 10.0 +/- 3.5 hours; Ts, 14.3 +/- 2.3 hours; TG2, 4.3 hours; TM, 1.4 +/- 1.3 hours; and Tc, 30.0 +/- 6.1 hours. For cells exposed continuously to 3H-thymidine the values are: growth fraction, 67%; TG1, 6.5 hours; Ts, 13.0 hours; and TG2 + M, 3.0 hours. The average doubling time is 4.6 days (range, 3.8-4.7 days); after about 10 to 15 days in culture, the growth rate of freshly passaged cells declines markedly, as reflected by a growth curve with a much shallower slope. The changes are accompanied by a marked decline in the labeling index from 41.3% (range, 28.9%-53.7%) during the first 3 days of culture to less than 5% measured on day 21. Flow cytometry for DNA content-dependent cell cycle compartment distribution demonstrates an obvious decline in the proportion of S-phase cells and a marked accumulation of G2 phase cells as the cultures age. When the supernatant medium of ARH-77 cells grown for 10 days is replaced by fresh medium, a new burst of vigorous cellular growth is observed with a curve slope similar to that observed during the first 5 days of culture. If the 10-day-old supernatant medium is used to set up cultures with freshly harvested ARH-77 cells, their growth curve resembles that of 10-day-old cultures. However, this supernatant medium induces no decrease in the growth rate of other human tumor cells, suggesting that inhibition of cellular growth does not result from exhaustion of nutrients, but that ARH-77 cells produce a molecular mediator that specifically inhibits the growth of these cells. ARH-77 cells could be synchronized with a single treatment of 3 or 5 mM thymidine; (dThd) and cloning efficiency was 2% to 4% in a double-layer soft agar assay. Treatment for 1 hour with increasing concentrations of melphalan produced a threshold exponential survival curve (Dq = 0.45 microgram/ml and D0 = 0.35 microgram/ml, 1 hour).(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:ARH-77, an established human IgG-producing myeloma cell line. II. Growth kinetics, clonogenic capacity, chalone production, xenogeneic transplantations, and response to melphalan. 623 73

Many patients with solid tumours or haematological malignancies develop anaemia, and the use of chemotherapy aggravates this condition. Red blood cell transfusions are often necessary but are associated with many risks, including immunosuppressive effects that may increase the risk of tumour recurrence. Many clinical studies have shown that epoetin (recombinant human erythropoietin) therapy can ameliorate, or even prevent, the anaemia associated with chemotherapy and cancer (including solid tumours as well as multiple myeloma or lymphoma). Response, defined as a significant (>50%) reduction in the rate of transfusions and/or a significant (>2 g/dl) elevation of haemoglobin levels, is usually observed in about 60% of the patients, irrespective of the type of standard chemotherapy given. The decrease in transfusion requirements is the major objective of epoetin therapy, because they are costly, inconvenient and are associated with potential adverse effects. Epoetin therapy also brings about substantial improvements in various indices of quality of life that are proportional to changes in haemoglobin level. However, large dosages of epoetin are generally required and about 40% of patients do not respond even to very high dosages. A number of adverse effects of epoetin therapy have been observed in patients with renal failure. The most prominent include hypertension, headaches, seizures and thrombotic events. These complications can also occur in patients with renal failure who are not receiving epoetin. Their exact incidence has been assessed in placebo-controlled studies, which have demonstrated that there is no increased risk of thrombosis or seizure with epoetin. However, it is now generally accepted that 10 to 20% of haemodialysis patients will experience an elevation of blood pressure because of epoetin and there is no doubt that a rapid elevation of blood pressure may cause generalised seizures. In other settings, including anaemia associated with cancer, very few adverse effects have been attributed to epoetin. However, close monitoring of blood pressure should be implemented in patients with hypertension. There is no evidence that epoetin stimulates tumour growth. With the dosages of epoetin currently used, there is no evidence of stem cell competition, resulting in thrombocytopenia or neutropenia, or of stem cell exhaustion, producing secondary anaemia when treatment is stopped. Epoetin is a remarkably well tolerated drug that offers significant benefits in patients with cancer.
 ...
PMID:A risk-benefit assessment of epoetin in the management of anaemia associated with cancer. 980 42

It is now well documented that apoptosis represents the prevalent mode of death in lymphoid cultures and occurs spontaneously in late-exponential phase of batch cultures following nutrient exhaustion. In an attempt to enhance the cell survival of these cell lines, we have initially engineered nonproducing NS/0 myeloma cells with a vector expressing the adenoviral E1B-19K protein. NS/0 cells transfected with E1B-19K were found to be more resistant to apoptosis occurring in the late phase of batch culture and under stressful conditions such as cultivation in glutamine-free medium or following heat shock. In this study, we have characterised a number of NS/0 subclones constitutively expressing different levels of E1B-19K, as well as several subclones in which the expression of E1B-19K was regulated by a tetracycline-controllable gene switch. We have found that a threshold E1B-19K level was required in order to achieve protection against apoptosis. The extent of resistance against cell death induced by nutrient deprivation in glutamine-free medium and in the late phase of batch cultures correlated with the level of E1B-19K expression up to an optimal level where further increases in E1B-19K levels did not result in significant additional protection. To assess the effects of E1B-19K on antibody productivity, an apoptosis-resistant NS/0 clone was then transfected with a chimeric antibody construct. Despite their improved viability, the antibody productivity of E1B-19K clones in batch culture was not significantly improved. Moreover, while the use of E1B-19K considerably delayed cell death, cells eventually died by apoptosis. Surprisingly, E1B-19K had no beneficial effect on the efficiency of fusion of NS/0 myelomas and splenocytes for the generation of hybridoma cells. Furthermore, the resulting hybridomas, although expressing E1B-19K at levels comparable to the myeloma parent, were no longer resistant to apoptosis. This indicates that the ability of E1B-19K to prevent apoptosis is not only dose-dependent but also seems to be cell-type dependent.
 ...
PMID:Dose-dependent reduction of apoptosis in nutrient-limited cultures of NS/0 myeloma cells transfected with the E1B-19K adenoviral gene. 1039 8

Multiple myeloma (MM) is associated with severe normochromic/normocytic anemia. This study demonstrates that the abnormal up-regulation of apoptogenic receptors, including both Fas ligand (L) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), by highly malignant myeloma cells is involved in the pathogenesis of the ineffective erythropoiesis and chronic exhaustion of the erythroid matrix. By measuring Fas-L and TRAIL in plasma cells and the content of glycophorin A (GpA) in erythroblasts from a cohort of 28 untreated, newly diagnosed patients with MM and 7 with monoclonal gammopathy of undetermined significance (MGUS), selected in relation to their peripheral hemoglobin values, results showed that both receptors occurred at high levels in 15 severely anemic MM patients. Their marrow erythropoietic component was low and included predominantly immature GpA(+dim) erythroblasts, in contrast with the higher relative numbers of mature GpA(+bright) erythroid cells observed in the nonanemic patients and those with MGUS. In cocultures with autologous Fas-L(+)/TRAIL(+) myeloma cells, the expanded GpA(+dim) erythroid population underwent prompt apoptosis after direct exposure to malignant plasma cells, whereas erythroblasts from nonanemic patients were scarcely affected. The evidence that Fas-L(+)/TRAIL(+) malignant plasma cells prime erythroblast apoptosis by direct cytotoxicity was also supported by the increase of FLICE in fresh immature GpA(+dim) erythroid cells, whereas ICE and caspase-10 increased in subsequent maturative forms. In addition, GATA-1, a survival factor for erythroid precursors, was remarkably down-regulated in fresh erythroblasts from the severely anemic patients. These results indicate that progressive destruction of the erythroid matrix in aggressive MM is due to cytotoxic mechanisms based on the up-regulation in myeloma cells of Fas-L, TRAIL, or both. It is conceivable that the altered regulation of these receptors defines a peculiar cytotoxic phenotype that drives the progression of aggressive MM.
 ...
PMID:Negative regulation of erythroblast maturation by Fas-L(+)/TRAIL(+) highly malignant plasma cells: a major pathogenetic mechanism of anemia in multiple myeloma. 1183 Apr 80

Anemia is a common complication in patients with hematologic malignancies, and is caused by a variety of mechanisms, including neoplastic cell infiltration into the bone marrow, hemolysis, nutritional deficiencies, and defects in erythropoiesis as a result of the disease itself or cytotoxic therapy. The anemia associated with multiple myeloma is caused by inadequate erythropoietin levels consequent to renal impairment and the effect of inflammatory cytokines. The degree of anemia can have prognostic importance, as is the case with multiple myeloma, or be a significant indicator of disease stage, as noted with chronic lymphocytic leukemia. Anemia results in fatigue, exhaustion, dizziness, headache, dyspnea, and decreased motivation, seriously affecting a patient's quality of life. Since anemia is so prevalent in hematologic malignancy patients, its treatment must be an integral part of disease management, to improve quality of life and to possibly increase potential survival. Clinical studies have shown that effectively treating anemia and increasing hemoglobin levels using recombinant human erythropoietin (rHuEPO, epoetin alfa) has a significant effect on transfusion requirements and quality of life.
 ...
PMID:The effects of anemia in hematologic malignancies: more than a symptom. 1208 53

Anemia of variable severity occurs in more than two-thirds of patients with multiple myeloma (MM). Besides the altered cytokine network, chronic erythropoietin deficiency, blood loss and hemolysis, we have shown that deregulated myeloma cell apoptosis may contribute to progressive destruction of the erythroid matrix by inducing erythroblast cytotoxicity. To exert this effect, highly malignant plasma cells overexpress both Fas-ligand (Fas-L) and TRAIL, which efficiently trigger the death of immature erythroblasts. In view of severe progression of MM in patients with Fas-L/TRAIL-based anemia, overexpression of these apoptogen receptors may characterize a peculiar cytotoxic-apoptogenic phenotype in malignant plasma cells. Early immunophenotyping of myeloma cells could thus help to identify patients with a higher risk of erythropoiesis exhaustion.
 ...
PMID:Anemia in multiple myeloma: role of deregulated plasma cell apoptosis. 1240 May 94

Mouse myeloma NS0 cells widely used in hybridoma technology lack the expression of a major stress protein Hsp70 which is the principal component of the basic cellular defense mechanism. These cells rapidly undergo apoptosis at the late-stationary phase of batch culture following nutrient exhaustion. Since Hsp70 was recently demonstrated to protect cells against numerous apoptotic stimuli, the aim of the present study was to examine the protective potential of the protein expression in engineered myeloma NS0 cells and in resulting hybridomas. Myeloma cells were transfected with the hsp70 gene under beta-actin gene promoter. To imitate harmful conditions that hybridoma or myeloma cells often experience when cultivated in large scale for an antibody production, NS0(wt) and NS0(hsp70) cell cultures were maintained without changing the medium for a few days, and the expression of apoptotic markers has been studied. It was found that long-term cultivation induced apoptosis in original cells manifested by typical nuclei fragmentation, DNA ladders and activation of caspase-3. In contrast, in transfected cells under the same conditions the outcome of apoptosis was postponed for 24 hours. Most relevant was that the fusion of transfected myeloma cells with immune splenocytes resulted in twofold hybridomas output compared with wild-type fusion partner. Almost half of the hybridomas continued to be hsp70-positive and maintained higher robustness in culture. The level of monoclonal antibodies production by hybridoma cells obtained with the use of NS0(wt) and NS0(hsp70) was similar, however, the secreted product was better preserved in culture supernatants of Hsp70-positive cells. It is concluded that transfection of mouse myeloma cells with the hsp70 gene can be a novel means to increase hybridoma yield and reduce the sensitivity of myeloma and hybridoma cells to culture conditions insults accompanying monoclonal antibody production.
 ...
PMID:Transfection of NS0 myeloma fusion partner cells with HSP70 gene results in higher hybridoma yield by improving cellular resistance to apoptosis. 1249 34

Anemia of variable severity occurs in more than two-thirds of patients with multiple myeloma (MM). Besides the altered cytokine network, chronic erythropoietn deficiency, blood loss and hemolysis, we have shown that deregulated myeloma cell apoptosis contributes to progressive destruction of the erythroid matrix by inducing erythroblast cytotoxicity. To exert this effect, highly malignant plasma cells overexpress both Fas-L and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which efficiently trigger the death of immature erythroblasts. However, this Fas-L/TRAIL-based anemia occurs in particular in patients with severely progressive MM, thus suggesting that these apoptogen receptors may characterize a peculiar cytotoxic-apoptogenic phenotype of malignancy. Immunophenotyping of myeloma cells could help to identify patients with a higher risk of erythropoiesis exhaustion.
 ...
PMID:Upregulation of erythroblast apoptosis by malignant plasma cells: a new pathogenetic mechanism of anemia in multiple myeloma. 1273 14

Immunomodulatory drugs (IMiDs) and bortezomib have been recently used in the management of patients with both newly diagnosed and relapsed/refractory multiple myeloma. Except of their direct anti-myeloma effect, these agents also alter the interactions between myeloma cells and marrow microenvironment. Several recent studies have investigated their potential effect on myeloma bone disease. Preclinical studies have demonstrated that IMiDs reduce osteoclast formation and function in vitro. Clinical studies have confirmed that thalidomide reduces markers of bone resorption, while lenalidomide induces osteoclast arrest in myeloma patients. However, IMiDs seem to have no effect on osteoblast exhaustion present in myeloma. The proteasome inhibitor bortezomib restores abnormal bone remodeling through the inhibition of osteoclast function and the increase in osteoblast differentiation and activity in vitro. In myeloma patients, bortezomib reduces biochemical markers of bone resorption and normalizes the RANKL/osteoprotegerin ratio, while at the same time increases bone formation markers reducing levels of dickkopf-1 protein. Whether these effects are direct and not only a consequence of the agents' antimyeloma activity is not totally clear. This review summarizes all available data for these attractive agents that combine potent anti-myeloma activity with beneficial effects on bone and may alter the way of management of myeloma-related bone disease.
 ...
PMID:The effect of novel anti-myeloma agents on bone metabolism of patients with multiple myeloma. 1797 55


1 2 3 4 Next >>