Yukako Ono

Induction of functional platelets from mouse and human fibroblasts by p45NF-E2/Maf

Determinant factors leading from stem cells to megakaryocytes (MKs) and subsequently platelets have yet to be identified. We now report that a combination of nuclear factor erythroid-derived 2 p45 unit (p45NF-E2), Maf G, and Maf K can convert mouse fibroblast 3T3 cells and adult human dermal fibroblasts into MKs. To screen MK-inducing factors, gene expressions were compared between 3T3 cells that do not differentiate into MKs and 3T3-L1 cells known to differentiate into MKs. 3T3 cells transfected with candidate factors were cultured in a defined MK lineage induction medium. Among the tested factors, transfection with p45NF-E2/MafG/MafK lead to the highest frequency of CD41-positive cells. Adult human dermal fibroblasts transfected with these genes were cultured in MK lineage induction medium. Cultured cells had megakaryocytic features, including surface markers, ploidy, and morphology. More than 90% of MK-sized cells expressed CD41, designated induced MK (iMK). Infusion of these iMK cells into immunodeficient mice led to a time-dependent appearance of CD41-positive, platelet-sized particles. Blood samples from iMK-infused into thrombocytopenic immunodeficient mice were perfused on a collagen-coated chip, and human CD41-positive platelets were incorporated into thrombi on the chip, demonstrating their functionality. These findings demonstrate that a combination of p45NF-E2, Maf G, and Maf K is a key determinant of both megakaryopoiesis and thrombopoiesis.

Manufacturing Plants' Use of Temporary Workers: An Analysis Using Census Microdata

Using plant-level data from the Plant Capacity Utilization (PCU) Survey, we examine how manufacturing plants’ use of temporary workers is associated with the nature of their output fluctuations and other plant characteristics. We find that plants tend to hire temporary workers when their output can be expected to fall, a result consistent with the notion that firms use temporary workers to reduce costs associated with dismissing permanent employees. In addition, we find that plants whose future output levels are subject to greater uncertainty tend to use more temporary workers. We also examine the effects of wage and benefit levels for permanent workers, unionization rates, turnover rates, seasonal factors, and plant size and age on the use of temporary workers; based on our results, we discuss various views of why firms use temporary workers.

OP9 bone marrow stroma cells differentiate into megakaryocytes and platelets.

Platelets are essential for hemostatic plug formation and thrombosis. The mechanisms of megakaryocyte (MK) differentiation and subsequent platelet production from stem cells remain only partially understood. The manufacture of megakaryocytes (MKs) and platelets from cell sources including hematopoietic stem cells and pluripotent stem cells have been highlighted for studying the platelet production mechanisms as well as for the development of new strategies for platelet transfusion. The mouse bone marrow stroma cell line OP9 has been widely used as feeder cells for the differentiation of stem cells into MK lineages. OP9 cells are reported to be pre-adipocytes. We previously reported that 3T3-L1 pre-adipocytes differentiated into MKs and platelets. In the present study, we examined whether OP9 cells differentiate into MKs and platelets using MK lineage induction (MKLI) medium previously established to generate MKs and platelets from hematopoietic stem cells, embryonic stem cells, and pre-adipocytes. OP9 cells cultured in MKLI medium had megakaryocytic features, i.e., positivity for surface markers CD41 and CD42b, polyploidy, and distinct morphology. The OP9-derived platelets had functional characteristics, providing the first evidence for the differentiation of OP9 cells into MKs and platelets. We then analyzed gene expressions of critical factors that regulate megakaryopoiesis and thrombopoiesis. The gene expressions of p45NF-E2, FOG, Fli1, GATA2, RUNX1, thrombopoietin, and c-mpl were observed during the MK differentiation. Among the observed transcription factors of MK lineages, p45NF-E2 expression was increased during differentiation. We further studied MK and platelet generation using p45NF-E2-overexpressing OP9 cells. OP9 cells transfected with p45NF-E2 had enhanced production of MKs and platelets. Our findings revealed that OP9 cells differentiated into MKs and platelets in vitro. OP9 cells have critical factors for megakaryopoiesis and thrombopoiesis, which might be involved in a mechanism of this differentiation. p45NF-E2 might also play important roles in the differentiation of OP9 cells into MK lineages cells.

Hemorrhagic colonic ulcers caused by dasatinib for chronic myelogenous leukemia

Dasatinib, a multi-kinase inhibitor that is active against BCR-ABL1 and SRC family kinases, has been reported to exert notable efficacy in the treatment of imatinib-resistant or -intolerant chronic myeloid leukemia (CML) in all phases [1–5]. Dasatinib therapy is generally well tolerated, although severe hematological and non-hematological adverse events are observed. The most common non-hematological adverse events are gastrointestinal symptoms, fluid retention, and skin rash [1–5]. It is notable that gastrointestinal bleeding accounts for 14–26% of gastrointestinal adverse events due to dasatinib [1–6]. A recent report evaluating the bleeding diathesis due to dasatinib revealed that more than 80% of the bleeding was observed in the gastrointestinal tract [7]. However, the characteristics and clinical courses of gastrointestinal bleeding due to dasatinib are yet to be fully elucidated. Herein, we present a case of melena due to multiple colonic ulcers under dasatinib treatment for CML, in which colonic ulcers completely resolved within 12 days after discontinuation of dasatinib. A 43-year-old woman with chronic-phase CML had been initially treated with imatinib at a daily dose of 400 mg. A complete molecular response was achieved at 1 year after treatment with imatinib. However, 4 years after initiating imatinib therapy, leukocytosis (42.6 9 10/L) together with blasts in the peripheral blood (17%) was observed. Bone marrow examination showed increased blasts (11.8%) and additional chromosomal abnormality of t(21;21)(q22;q22), indicating a progression to the accelerated phase. Dasatinib (70 mg) was initiated twice daily, which successfully led to normalization of white blood cell count and disappearance of blasts from the peripheral blood. However, anemia and thrombocytopenia persisted, and red blood cell and platelet transfusions were required. She had had mild diarrhea shortly after initiating dasatinib, and suddenly developed melena 3 months after initiating dasatinib, when the platelet count was 21 9 10/L. Her white blood cell count was 3.8 9 10/L with 77% of neutrophils and 11% of lymphocytes. Endoscopic examination of the lower gastrointestinal tract showed multiple aphthous ulcers of the colon (Fig. 1a). Dasatinib was discontinued, and melena ceased in 2 days. As much as 12 days after the discontinuation of dasatinib, another endoscopic examination was performed, and showed almost complete resolution of ulcerative lesions of the colon (Fig. 1b). She then received total body irradiation (12 Gy), high-dose cytarabine, and cyclophosphamide as a conditioning for allogeneic cord blood transplantation, and has shown mild gastrointestinal toxicities, but has not developed melena since. In this case, we confirmed by endoscopy that hemorrhagic colonic ulcers probably caused by dasatinib almost completely healed within 12 days after discontinuation of dasatinib. The mechanism of dasatinib-induced gastrointestinal bleeding is yet to be understood. Its inhibitory activity against platelet-derived growth factor receptor (PDGFR) kinase might be a possible explanation, since PDGFR-b plays an important role in angiogenesis and Y. Ono T. Mori (&) J. Kato A. Yamane S. Okamoto Division of Hematology, Department of Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan e-mail: tmori@sc.itc.keio.ac.jp

Professional employer organizations: What are they, who uses them, and why should we care?

Using both public and confidential data, the authors summarize how the intensity of use of professional employer organization (PEO) services varies across industries and geographical areas. Their analyses using microdata of manufacturing establishments suggest that the use of PEO services depends on the size of the establishment and of its parent firm. The use of PEO services is greater for newly constructed establishments, as well as for establishments with a potentially high injury and illness rate. Greater diversification across industries and geographical areas of a parent firm may also increase an establishments use of PEO services.

Long‐term follow‐up of reduced‐intensity allogeneic hematopoietic stem cell transplantation for refractory or relapsed follicular lymphoma

Although allogeneic hematopoietic stem cell transplantation (HSCT) is considered the only curative treatment for refractory or relapsed follicular lymphoma (FL), transplant-related mortality (TRM) greatly interferes with the success. A variety of reduced-intensity conditionings (RICs) have been used to reduce TRM, but an optimal conditioning for FL has not been fully established. We retrospectively evaluated the outcome of allogeneic HSCT for FL with RIC consisting of fludarabine and melphalan. Nineteen adult patients with relapsed or refractory FL were conditioned with fludarabine (125 mg/m2) and melphalan (140 mg/m2), and received grafts from an HLA-identical sibling (n = 6) or an unrelated donor (n = 13). For the prophylaxis of graft-versus-host disease (GVHD), cyclosporine A or tacrolimus with short-term methotrexate was given. There were no early deaths before engraftment, and all patients achieved engraftment. Three patients died of extensive-type chronic GVHD (n = 2) or bacterial infection (n = 1) without disease progression. With a median follow-up period of 75.2 months (range: 33.3–111.9 months), 16 patients were alive without disease progression. Both the 5-year overall and progression-free survival rates were 84.2% (95% CI: 67.7–100%). These results strongly suggest that allogeneic HSCT with RIC using fludarabine and melphalan could be a promising treatment choice for refractory or relapsed FL.

Central line-associated bacteremia caused by drug-resistant Staphylococcus caprae after chemotherapy for acute myelogenous leukemia

Coagulase-negative staphylococci (CNS), including Staphylococcus epidermidis (S. epidermidis), have been recognized as a cause of nosocomial infections, mostly infection at sites of indwelling devices. The species that most frequently cause infection in humans is S. epidermidis. However, other species of CNS are increasingly recognized as causative pathogens of infection. S. caprae was originally isolated from goat’s milk, and has been considered to be infrequently detected in human clinical samples. There have been only a limited number of cases of infection due to S. caprae, most of which were associated with infection at sites of indwelling devices (i.e. orthopedic prostheses) [1–3]. To the best of our knowledge, only a few cases of bacteremia due to S. caprae have been reported [4–7]. We experienced a case of central line-associated bacteremia caused by S. caprae during a neutropenic period after anti-cancer chemotherapy for acute myeloid leukemia. A 46-year-old woman with acute myeloid leukemia received combination chemotherapy consisting of cytarabine (100 mg/m for 5 days) and idarubicin (12 mg/m for 2 days) via a central line that had been placed in the right jugular vein 1 day before initiating chemotherapy. For prophylaxis against bacterial and fungal infection, oral ciprofloxacin (600 mg/day) and itraconazole (200 mg/day) were simultaneously started. Sixteen days after initiating chemotherapy, when the neutrophil count was less than 0.1 9 10/L, the patient developed a high-grade fever. Although cefepime was initiated, she remained febrile. A series of blood cultures yielded Gram-positive cocci, which were later identified as S. caprae. ID 32 STAPH system (SYSMEX bioMérieux Co, Tokyo, Japan) was used for identification. The patient had neither contact with goats nor had she visited a farm. An echocardiogram revealed no findings of endocarditis. The isolate was only susceptible to vancomycin and linezolid, and resistant to oxacillin, penicillin G, ampicillin, cefazolin, cefepime, meropenem, imipenem, amikacin, ciprofloxacin, and clarithromycin. The isolate was positive for penicillin-binding protein (PBP)-20 and b-lactamase. In spite of the intravenous administration of vancomycin, blood cultures continued to yield S. caprae. Then, the central line was removed, and blood cultures became negative. After the cessation of 2week vancomycin therapy, bacteremia did not recur, and the patient recovered without sequelae. Because of the limited number of cases of infection due to S. caprae, the clinical course of infection and microbiological characteristics, including its susceptibility to antibiotic, remain to be fully elucidated. Besides indwelling device-associated bone or joint infection, S. caprae has also been reported as a causative pathogen of bacteremia, endocarditis, urinary tract infection, meningitis, and otitis externa [7–9]. As in the present case, previously reported cases of bacteremia due to S. caprae have been associated with intravascular catheters, especially in non-neonatal patients [7]. Thus, we think that S. caprae should be recognized as an emerging pathogen of intravascular catheterrelated bacteremia as well as other species of CNS. J. Kato T. Mori (&) Y. Ono A. Yamane T. Shimizu S. Okamoto Division of Hematology, Department of Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan e-mail: tmori@sc.itc.keio.ac.jp

Drug interaction between voriconazole and tacrolimus in allogeneic hematopoietic SCT recipients

Drug interaction between voriconazole and tacrolimus in allogeneic hematopoietic SCT recipients