Although information about the development of primitive and definitive hematopoiesis has been elucidated in murine embryos and embryonic stem (ES)cells, there have been few in vitro studies of these processes in primates. In this study, we investigated hematopoietic differentiation from cynomolgus monkey ES cells grown on OP9, a stromal cell line deficient in macrophage colony-stimulating factor. Primitive erythrocytes (EryP) and definitive erythrocytes (EryD) developed sequentially from ES cells in the culture system; this was confirmed by immunostaining and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of embryonic, fetal and adult globin genes. EryP were detected on day 8 without exogenous erythropoietin (EPO), whereas EryD appeared on day 16 and had an indispensable requirement for exogenous EPO. RT-PCR analysis of the cultures revealed a sequential expression of genes associated with primitive and definitive hematopoietic development that was equivalent to that seen during primate ontogeny in vivo. Vascular endothelial growth factor (VEGF) increased, in a dose-dependent manner, not only the number of floating hematopoietic cells,but also the number of adherent hematopoietic cell clusters containing CD34-positive immature progenitors. In colony assays, exogenous VEGF also had a dose-dependent stimulatory effect on the generation of primitive erythroid colonies. More efficient primitive and definitive erythropoiesis was induced by re-plating sorted CD34-positive cells. Thus, this system reproduces early hematopoietic development in vitro and can serve as a model for analyzing the mechanisms of hematopoietic development in primates.

Bacillus cereus is recognized as a major pathogenic bacterium that causes food poisoning and produces gastrointestinal diseases of 2 types: emetic and diarrheal. The emetic type, which is often linked to pasta and rice, arises from a preformed toxin, cereulide, in food. Rapid and accurate diagnostic methods for this emetic toxin are important but are limited. Here we describe 3 patients with B cereus food poisoning in which cereulide was detected and measured sequentially. Three family members began to vomit frequently 30 minutes after consuming reheated fried rice. After 6 hours, a 1-year-old brother died of acute encephalopathy. A 2-year-old sister who presented with unconsciousness recovered rapidly after plasma exchange and subsequent hemodialysis. Their mother recovered soon by fluid therapy. From leftover fried rice and the children's stomach contents, B cereus was isolated. Serum cereulide was detected in both children; it decreased to an undetected level in the sister. These cases highlight the importance of measuring the value of cereulide, which would reflect the severity of B cereus emetic food poisoning. The cases also suggest the possible role of blood-purification therapy in severe cases.

Sphere formation has been utilized as a way to isolate multipotent stem/progenitor cells from various tissues. However, very few studies on bone marrow-derived spheres have been published and assessed their multipotentiality. In this study, multipotent marrow cell populations were isolated using a three-step method. First, after elimination of hematopoietic cells, murine marrow-derived adherent cells were cultured in plastic dishes until small cells gradually appeared and multiplied. Cells were then cultured under non-adherent conditions and formed spheres that were immunopositive for a neural precursor marker, nestin. RT-PCR analysis also revealed that the spheres were positive for nestin in addition to PPARgamma, osf2, SOX9, and myoD, which are markers of precursors of adipocytic, osteoblastic, chondrocytic, and skeletal myeloblastic lineages, respectively. Finally, spheres were dissociated into single cells and expanded in adherent cultures. Under appropriate induction conditions, the sphere-derived cells acquired the phenotypic properties in vitro of neurons, skeletal myoblasts, and beating cardiomyocytes, as well as adipocytes, osteoblasts, and chondrocytes. Next, sphere-derived cells were transplanted into murine myocardial infarction models. One month later, they had become engrafted as cardiomyocytes, and cardiac catheterization showed significant functional improvements. Thus, sphere-derived cells represent a new approach to enhance the multi-differentiation potential of murine bone marrow.

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We identified intermediate-stage progenitor cells that have the potential to differentiate into hematopoietic and endothelial lineages from nonhuman primate embryonic stem (ES) cells. Sequential fluorescence-activated cell sorting and immunostaining analyses showed that when ES cells were cultured in an OP9 coculture system, both lineages developed after the emergence of two hemoangiogenic progenitor-bearing cell fractions, namely, vascular endothelial growth factor receptor (VEGFR)-2 high CD34 -and VEGFR-2 high CD34 ؉ cells. Exogenous vascular endothelial growth factor increased the proportion of VEGFR-2 high cells, particularly that of VEGFR-2 high CD34 ؉ cells, in a dose-dependent manner. Although either population of VEGFR-2 high cells could differentiate into primitive and definitive hematopoietic cells (HCs), as well as endothelial cells (ECs), the VEGFR-2 high CD34 ؉ cells had greater hemoangiogenic potential. Both lineages developed from VEGFR-2 high CD34 -or VEGFR-2 high CD34 ؉ precursor at the single-cell level, which strongly supports the existence of hemangioblasts in these cell fractions. Thus, this culture system allows differentiation into the HC and EC lineages to be defined by surface markers. These observations should facilitate further studies both on early developmental processes and on regeneration therapies in human.

The objectives of this study are to clarify (1) the difference in demographic and clinical variables at initial presentation between acute and chronic idiopathic thrombocytopenic purpura (ITP), and (2) the prognostic factors of patients with chronic ITP. We conducted a retrospective analysis of 247 children with newly diagnosed ITP between April 1991 and March 2006 who visited one of the 12 hospitals belonging to the Kyoto University Pediatric Hematologic Study Group. 180 and 67 cases were classified as the acute type and as the chronic type, respectively. Older age, higher initial platelet count, positive medical history or concomitant medical diagnosis, the absence of preceding infection or vaccination, and the absence of an increase in immunoglobulin were risk factors for the chronicity. The prognostic factors in chronic ITP were evaluated in 53 patients after excluding patients receiving splenectomy or having insufficient follow-up data. The overall time required for 50% resolution in patients with chronic ITP was approximately 5.6 years. Age at presentation of less than 3 years and higher platelet counts at the time of chronic ITP diagnosis were good prognostic factors. On the other hand, gender, initial platelet counts, and preceding infection or vaccination were not associated with the prognosis.

Several studies have shown that hepatocytes can be generated from hematopoietic stem cells, but this event is believed to be rare and to require hepatic damage. To investigate this phenomenon in human cells, we used a NOD/SCID/gamma(c)null (NOG) mouse model that can achieve a tremendously high level of chimerism when transplanted with human hematopoietic cells. Even without hepatotoxic treatment other than irradiation, human albumin and alpha-1-antitrypsin-positive cells were invariably detected in the livers of NOG mice after i.v. transplantation of human cord blood CD34+ cells. Human albumin was detected in the murine sera, indicating functional maturation of the human hepatocytes. Flow cytometric analysis of recipient liver cells in single-cell suspension demonstrated that human albumin-positive cells were also positive for both murine and human MHC and were negative for human CD45. PCR analysis of recipient livers revealed the expression of a wide variety of human hepatocyte- or cholangiocyte-specific mRNAs. These results show that human CD34+ cells fuse with hepatocytes of NOG mice without liver injury, lose their hematopoietic phenotype, and begin hepatocyte-specific gene transcription. These phenomena were not observed when CD34- cells were transplanted. Thus, our model revealed a previously unidentified pathway of human hematopoietic stem/progenitor cell differentiation.

Recurrent fusion genes involving C11orf95, C11orf95-RELA, have been identified only in supratentorial ependymomas among primary CNS tumors. Here, we report hitherto histopathologically unclassifiable high-grade tumors, under the tentative label of "ependymoma-like tumors with mesenchymal differentiation (ELTMDs)," harboring C11orf95-NCOA1/2 or -RELA fusion. We examined the clinicopathological and molecular features in five cases of ELTMDs.Except for one adult case (50 years old), all cases were in children ranging from 1 to 2.5 years old. All patients presented with a mass lesion in the cerebral hemisphere. Histologically, all cases demonstrated a similar histology with a mixture of components. The major components were embryonal-appearing components forming well-delineated tumor cell nests composed of small uniform cells with high proliferative activity, and spindle-cell mesenchymal components with a low-to high-grade sarcoma-like appearance. The embryonal-appearing components exhibited minimal ependymal differentiation including a characteristic EMA positivity and tubular structures, but histologically did not fit with ependymoma because they lacked perivascular pseudorosettes, a histological hallmark of ependymoma, formed well-delineated nests, and had diffuse and strong staining for CAM5.2. Molecular analysis identified C11orf95-NCOA1, -NCOA2, and -RELA in two, one, and two cases, respectively. t-distributed 2 of 14 | TOMOMASA eT Al.