Effect of methotrexate and sulphasalazine on UMR 106 rat osteosarcoma cells

Methotrexate is commonly used in the treatment of rheumatoid arthritis. An osteopathy has been described in children treated with methotrexate for leukaemia, consisting of bone pain, osteoporosis and fractures. Animals given short-term high-dose and long-term low-dose methotrexate have both reduced bone formation and increased resorption on histomorphometry. As patients with rheumatic diseases have numerous risk factors for osteoporosis, possible additional risk from low-dose methotrexate is of relevance to the rheumatologist. To investigate further the mechanism of osteoporosis in animals and man, in vitro studies were carried out on an osteoblast cell line, using concentrations found in patients with rheumatic disease. UMR 106 rat osteoblast-like osteosarcoma cells were incubated with methotrexate, and also with sulphasalazine, an anti-rheumatic drug with no known effect on bone, for comparison. A dose-dependent toxic effect of methotrexate on the cell line was observed using concentrations found in patients with rheumatic disease. This was not observed with sulphasalazine. The reduced bone formation observed in animals and man may be due to a direct effect of methotrexate on the osteoblast.      

Kinetics of factor VIII-von Willebrand factor association

The binding of factor VIII to von Willebrand factor (vWF) is essential for the protection of factor VIII against proteolytic degradation in plasma. We have characterized the binding kinetics of human factor VIII with vWF using a centrifugation binding assay. Purified or plasma vWF was immobilized with a monoclonal antibody (MoAb RU1) covalently linked to Sepharose (Pharmacia LKB Biotechnology, Uppsala, Sweden). Factor VIII was incubated with vWF-RU1-Sepharose and unbound factor VIII was separated from bound factor VIII by centrifugation. The amount of bound factor VIII was determined from the decrease of factor VIII activity in the supernatant. Factor VIII binding to vWF-RU1-Sepharose conformed to the Langmuir model for independent binding sites with a Kd of 0.46 +/- 0.12 nmol/L, and a stoichiometry of 1.3 factor VIII molecules per vWF monomer at saturation, suggesting that each vWF subunit contains a binding site for factor VIII. Competition experiments were performed with a recombinant vWF (deltaA2-rvWF), lacking residues 730 to 910 which contain the epitope for MoAB RU1. DeltaA2-rvWF effectively displaced previously bound factor VIII, confirming that factor VIII binding to vWF-RU1-Sepharose was reversible. To determine the association rate constant (k(on)) and the dissociation rate constant (k(off)), factor VIII was incubated with vWF-RU1-Sepharose for various time intervals. The observed association kinetics conformed to a simple bimolecular association reaction with k(on) = 5.9 +/- 1.9 x 10(6) M(-1) s(-1) and k(off) = 1.6 +/- 1.2 x 10(-3) s(-1) (mean +/- SD). Similar values were obtained from the dissociation kinetics measured after dilution of preformed factor VIII-vWF-RU1-Sepharose complexes. Identical rate constants were obtained for factor VIII binding to vWF from normal pooled plasma and to vWF from plasma of patients with hemophilia A. The kinetic parameters in this report allow estimation of the time needed for complex formation in vivo in healthy individuals and in patients with hemophilia A, in which monoclonally purified or recombinant factor VIII associates with endogenous vWF. Using the plasma concentration of vWF (50 nmol/L in monomers) and the obtained values for K(on) and K(off), the time needed to bind 50% of factor VIII is approximately 2 seconds.     

Acute promyelocytic leukemia: treatment results during a decade at Memorial Hospital

Fifty-seven adult patients with acute promyelocytic leukemia (APL) were treated between 1974 and 1984 with daunorubicin (DNR) or 4-(9- acridinylamino)methanesulfan-m-anisidide (AMSA) in combination with arabinosylcytosine (Ara-C) and 6-thioguanine (TG); they also received prophylactic heparin. Forty-one patients (72%) achieved complete remission (CR), including 11 of 12 patients who received the AMSA- containing regimen. The incidence of early fatal hemorrhage was 14%, lower than that of earlier studies or other published reports. Elevated WBC and serum lactate dehydrogenase levels at diagnosis were associated with an increased incidence of life-threatening hemorrhage and shorter remission duration. Advanced age was an unfavorable prognostic factor for male patients. Both DNR and AMSA in combination protocols are effective treatments for APL. The incidence of CR is similar to that achieved in other types of acute nonlymphoblastic leukemia (ANLL) with the same protocols, but the median duration of remission is significantly longer in APL (24 v 9 months) and the percentage of remissions longer than 60 months is also higher in APL (35% v 5%).     

食管球囊联合超细胃镜扩张贲门失弛缓症1例

对1例中年贲门失弛缓症患者于超细胃镜直视下应用食管球囊预扩张一次的基础上,将胃镜插至胃底反转对球囊定位后再次扩张.扩张口径满意,无穿孔；症状缓解,随访1mo无复发.     

Positive Coombs test in Hodgkin's disease: significance and implications

To clarify the clinicopathologic characteristics of Coombs' positivity in Hodgkin's disease, the records of 71 cases were reviewed. The direct Coombs test was positive in seven. Mean age of the seven was 22 yr (range 11-33). All were males. All had extensive disease (pathologic stage III or IV) and six had systemic (B) symptoms. Four had mixed cellularity; three had nodular sclerosis. The positive Coombs test was detected at original diagnosis in three and at time of relapse in four. Although all were anemic, only three had evidence of overt hemolysis. The antibody responsible for Coombs positivity was characterized in three and fulfilled the criteria for IgG anti-It. The presence of a positive direct Coombs test in the patient with Hodgkin's disease suggests active and advanced disease. The presence of IgG anti-It may represent a unique antibody in the Coombs-positive hemolytic anemia associated with Hodgkin's disease.     

Hematopoietic stem cells in the blood after stem cell factor and interleukin-11 administration: evidence for different mechanisms of mobilization

Peripheral blood stem cells and progenitor cells, collected during recovery from exposure to cytotoxic agents or after cytokine administration, are being increasingly used in clinical bone marrow transplantation. To determine factors important for mobilization of both primitive stem cells and progenitor cells to the blood, we studied the blood and splenic and marrow compartments of intact and splenectomized mice after administration of recombinant human interleukin-11 (rhlL-11), recombinant rat stem cell factor (rrSCF), and IL-11 + SCF. IL-11 administration increased the number of spleen colony- forming units (CFU-S) in both the spleen and blood, but did not increase blood long-term marrow-repopulating ability (LTRA) in intact or splenectomized mice. SCF administration increased the number of CFU- S in both the spleen and blood and did not increase the blood or splenic LTRA of intact mice, but did increase blood LTRA to normal marrow levels in splenectomized mice. The combination of lL-11 + SCF syngeristically enhanced mobilization of long-term marrow-repopulating cells from the marrow to the spleen of intact mice and from the marrow to the blood of splenectomized mice. These data, combined with those of prior studies showing granulocyte colony-stimulating factor mobilization of long-term marrow repopulating cells from the marrow to the blood of mice with intact spleens, suggest different cytokine- induced pathways for mobilization of primitive stem cells.     

Whole body potassium and total exchangeable potassium in elderly patients with cardiac-failure.

Body potassium status of patients with cardiac failure may be estimated by a number of methods, but increasing reliance is being placed upon radioisotope dilution with 42K which measures the total exchangeable potassium. Total exchangeable potassium comprises between 86 per cent and 97 per cent of whole body potassium in healthy subjects. We have measured total exchangeable potassium in 22 oedema-free elderly patients with stable cardiac failure and compared the results with simultaneously determined measurements of whole body potassium obtained by whole body counting. The mean whole body potassium was 2360 +/- 640 mmol. The mean value of total exchangeable potassium measured at 24 hours was 1820 +/- 610 mmol (77% of whole body potassium) and increased further to 2000 +/- 600 mmol (84%) when measured after 48 hours. In patients with cardiac failure and, perhaps, also other patients with a history of fluid retention, the mixing of a tracer dose may be significantly delayed, which if not appreciated may lead to an overestimate of potassium depletion.     

Understanding influenza vaccination attitudes at a Canadian cancer center

BACKGROUND: Although influenza vaccination benefits both health care workers and their patients, participation by staff in vaccination programs is disappointingly low. Understanding health care worker perceptions and needs is essential for improving rates of vaccination. METHODS: A self-administered questionnaire was distributed to all staff at a Canadian cancer center. Information was sought on previous frequency of participation in influenza vaccination, as well as motivations, perceptions, and preferences. RESULTS: Three hundred sixty-three (70%) of 515 cancer center staff members responded. Twenty-two percent of staff were vaccinated 4 or 5 times in the past 5 years and were primarily motivated by the desire to protect their own health (81%). Forty-nine percent participated 1 to 3 times in the past 5 years, and this group had diverse knowledge and vaccine-access needs. Twenty-nine percent received no vaccination in the previous 5 years because they believed the vaccine lacked efficacy (45%) or was harmful to health (19%). Moving from high to low levels of participation with influenza vaccination, the following trends were observed: increasing belief that vaccines cause illnesses or weaken the immune system, increasing belief that adverse effects of vaccination are underreported, and decreasing belief that vaccination programs are beneficial. CONCLUSIONS: Cancer center staff perceptions about influenza vaccination differ according to the past frequency of vaccine uptake. Strategies for promoting vaccination should be guided by these differences.     

Bone marrow ablation followed by allogeneic marrow grafting during first complete remission of acute nonlymphocytic leukemia

Of 33 patients who had undergone allogeneic bone marrow transplantation during first complete remission of acute nonlymphocytic leukemia, 21 patients have now been followed in continued complete remission for 6- 64 mo (median greater than 18 mo) without maintenance chemotherapy. The median age of the surviving patients is 27 yr. Transplant-related complications occurring throughout the first year after marrow grafting were fatal in 7 patients, and leukemic recurrence led to the death of 5 patients. The actuarial long-term disease-free survival is 60% and the actuarial remission rate is 79%.     

Characterization of murine CD34, a marker for hematopoietic progenitor and stem cells

CD34 is expressed on human hematopoietic stem and progenitor cells, and its clinical usefulness for the purification of stem cells has been well established. However, a similar pattern of expression for murine CD34 (mCD34) has not yet been determined. Two polyclonal anti-mCD34 antibodies that specifically recognize both endogenous and recombinant murine CD34 were developed to characterize the mCD34 protein and to determine its pattern of expression on murine cell lines and hematopoietic progenitor cells. Fluorescence-activated cell sorter analysis showed that mCD34 is expressed on NIH/3T3 embryonic fibroblasts, PA6 stromal cells, embryonic stem cells, M1 leukemia cells, and a subpopulation of normal bone marrow cells. Murine CD34 was found to be a glycoprotein expressed on the cell surface as either a full-length (approximately 100 kD) or truncated (approximately 90 kD) protein in NIH/3T3 and PA6 cells. Recombinant full-length CD34, when expressed in the CHO-K1 cell line, had a molecular weight of approximately 105 kD. Full-length CD34 expressed on M1 leukemia cells, had a higher apparent molecular weight (110 kD). These results suggest that there are glycosylation differences between CD34 expressed by different cell types. The full-length form, but not the truncated form, is a phosphoprotein that is hyperphosphorylated in response to 12-0- Tetradecanoyl phorbol 13-acetate treatment, suggesting potential functional differences between the two forms. Selection of the 3% highest-expressing CD34+ bone marrow cells enriched for the hematopoietic precursors that form colony-forming unit-spleen (CFU-S), CFU-granulocyte-macrophage, and burst-forming unit-erythroid. Transplantation of lethally irradiated mice with these cells demonstrated both short- and long-term repopulating ability, indicating that this population contains both functional hematopoietic progenitors and the putative stem cell. These antibodies should be useful to select for murine hematopoietic stem cells.