A 42-year-old man was diagnosed as having refractory anemia in May, 2001. He developed overt leukemia and received allogeneic bone marrow transplantation (BMT). His younger brother, a 40-year-old man, was diagnosed as having acute leukemia with trilineage myelodysplasia in November, 2001. Although he was treated with conventional chemotherapy, he failed to achieve complete remission. He also received allogeneic BMT. We suggest that environmental factors in addition to a genetic defect in the pluripotent hematopoietic stem cells may be associated with the occurrence of this familial leukemia.

We describe a 51-year-old woman with recurrent follicular lymphoma from the age of 47 despite chemo-radio therapy, who subsequently underwent nonmyeloablative stem cell transplantation with conditioning consisting of fludarabine and low-dose total body irradiation (2 Gy). Myelosuppression was very mild, so the patient required no transfusions. Chimerism analysis from peripheral blood showed that T-cell mixed chimerism continued over 12 months after stem cell transplantation (the percentage of recipient T-cells was approximately 20%). Despite this, the lymphadenopathy disappeared, and the patient developed grade II acute GVHD (graft versus host disease). It has been considered that the establishment of full donor chimerism is required to induce GVHD and GVM (graft versus malignancy) effects. In this case, however, an allo-response was observed despite the persistence of T-cell mixed chimerism.

The chimeric anti-CD20 monoclonal antibody rituximab was recently approved for the treatment of malignant B cell lymphoma. We report the case of a 49 year-old female with advanced mantle cell lymphoma (MCL), who successfully underwent auto-peripheral blood stem cell transplant (auto-PBSCT) in combination with in vivo purging of tumor cells using rituximab. Systemic swelling was detected in her lymph nodes, and she was histologically diagnosed with MCL. From bone marrow involvement and 28% of lymphoma cells in her peripheral blood, she was identified as stage IV of MCL. She achieved a partial response (PR) after three cycles of standard chemotherapy (ProMACE-CytaBOM) followed by 1 course of rituximab at 375 mg/m2 per week for four weeks. Prior to treatment with rituximab, IgH/bcl-1 translocation in her peripheral blood was found to be positive in 0.5% of 199 cells. After administration of rituximab, this fell to 0% in her peripheral blood and bone marrow. Stem cells were mobilized with cyclophosphamide at 2,000 mg/m2 for 2 days, followed by granulocyte colony-stimulating factor (G-CSF). On one day prior to harvest, rituximab was infused at 375 mg/m2 for in vivo purging of tumor cells. The IgH/bcl-1 translocation in the peripheral blood stem cell harvest (PBSCH) product was found to be 0%. Subsequently, a pretreatment regimen of CBDCA at 350 mg/m2 x 4, ETP at 500 mg/m2 x 3, MCNU at 200 mg/m2 x 1, and CPA at 2,000 mg/m2 x 2 was adopted to condition the transplant, followed by auto-PBSCT. After the transplant, the patient achieved an uncertain complete response (CRu). The present case suggests in vivo purging with rituximab is effective, and that this method may have a role as a first-line therapy in MCL patients who respond poorly to standard treatment.

The establishment of human embryonic stem (ES) cell lines has brought great potential and expectations for regenerative medicine and pharmaceutical research, because many types of human cells could be produced by their unlimited growth and differentiation in culture. Primate and human ES cell lines have been established from blastocysts of monkey and surplus human blastocysts from fertility clinics. They showed several differences compared to mouse ES cells, including a tendency to produce the trophectoderm lineage and a different expression pattern of surface antigens. This may reflect species-specific differences, or these primate ES cells could represent earlier stages of development than mouse ES cells. Also, they show no response to the LIF and gp130 signals, which are widely used to repress spontaneous differentiation of mouse ES cell colonies. We have established several ES cell lines from blastocysts of the cynomolgus monkey. They can be maintained in culture as stem cell colonies, and they produce several differentiated cell types in culture. When such ES cells were transplanted into SCID mice, they produced teratomas containing many differentiated tissues.

Multipotent stem cells that can generate neurons and glial cells exist in various regions of the vertebrate central nervous system (CNS) during development. The multipotent neural stem cells were isolated from rat embryonic day 14 (E14) or mouse E12 cortex and cultured by neurosphere formation in serum-free medium in the presence of basic fibroblast growth factor (bFGF). Differentiation was induced by the addition of 10% FBS to low density cultures (2.5 x 10(3) cells/cm2). Immunological analyses and RT-PCR indicated that neural stem cells gave rise to both endothelial cells and smooth muscle cells (SMCs). A reconstituted collagen gel fiber of NSC-derived SMCs caused contractions in response to typical contractile agonists (Oishi K. et al., J. Physiol., 540, 139-152, 2002). Moreover, neural stem cells subcultured into a collagen gel formed endothelial tube-like structures (Kawakita E, et al., J Smooth Muscle Res 6, J-33, 2002). These results arise one possibility that blood vessel cells in head are at least in part derived from NSCs.

Recombinant human erythropoietin(rHuEpo) is effective for the treatment of renal anemia associated with chronic renal failure(CRF). However, we have encountered some patients with CRF who have sometimes developed a resistance to rHuEpo. This resistance can be due to iron or folate deficiency, aluminum toxicity, hyperparathyroidism, or auto-antibodies for rHuEpo. In this study, we focused on the soluble erythropoietin receptor(sEpoR), which can bind to rHuEpo. To demonstrate the possibility that the sweeping of rHuEpo by sEpoR results in resistance to rHuEpo, we performed a bioassay using the rHuEpo-dependent cell line, UT7/EPO. The results showed that recombinant mouse sEpoR(rmsEpoR) can reduce the proliferation of UT7/EPO induced by rHuEpo in a dose-dependent manner. We consider that this cell line could be a useful tool in a bioassay to detect the inhibitory factor(s) against Epo. We selected sera from three groups of patients with renal anemia associated with CRF who were receiving hemodialysis three times a week: the first was a patient group that needed a high dose of rHuEpo(7,500-9,000 unit/dialysis), the second was a patient group that needed an intermediate dose of rHuEpo (4,500 unit/dialysis), the third was a patient group that needed a low dose of rHuEpo(below 1,500 unit/dialysis). Interestingly, the proliferation of UT7/EPO determined with [3H]-thymidine incorporation was reduced by the addition of sera from the first group, but not by the addition of sera from the third group. These results suggested that serum sEpoR may play an important role in signal transduction via EpoR on erythroid progenitor in CRF patients.

We describe the case of a 23-year-old man with acute lymphoblastic leukemia in whom the Philadelphia chromosome was first detected in the late stage of the disease. At diagnosis, the patient's leukocyte count was 39,400/microliter and leukemic cells were positive for CD10, 19, 20, 33, 34 and HLA-DR. Karyotypic analysis at diagnosis revealed 46,XY. Complete remission was achieved after the first induction therapy, but the disease recurred after 9 months. The patient underwent allogeneic peripheral blood stem cell transplantation from his HLA identical mother, but relapse occurred on day 80. The proportion of bone marrow lymphoblasts decreased transiently after donor lymphocyte infusion but later increased, and the patient died on day 362. The Philadelphia chromosome was first detected by karyotypic analysis on day 256. p190-type bcr/abl mRNA transcripts were negative following RT-PCR at the initial diagnosis, but became positive from the first relapse through the late stage. Generally, the product of the bcr/abl fusion gene has been thought to play an important role in leukemogenesis, however the present case suggests that this gene product is also related to disease progression.

Renal cell carcinoma (RCC) is an immunogenic tumor that has shown some response to cytokine-therapy and other types of immune-based treatment. Since the advent of lymphocyte culture techniques in the 1980s, clinical trials of lymphokine-activatedkiller cells and tumor infiltrating lymphocytes have been conducted. Although these approaches have not shown apparent benefit compared to the standard cytokine therapy, further trials are ongoing using dendritic cell or gene-modified tumor vaccines in order to induce a tumor-specific cytotoxic T cell response in vivo. Recently, several investigators have indicated that RCC is susceptible to a graft-versus-tumor effect promoted by allogeneic stem-cell transplantation. This article reviews the clinical results of these cell therapies for metastaic RCC.

There has been increasing interest in recent years in the phenomenon of "regeneration," especially in the function of the bone marrow stromal cell system in the support of hematopoiesis. The stromal cell system has been proposed to consist of mesodermal stem cells that are capable of self-renewal and differentiation into a variety of mesodermal tissues, including bone, cartilage, tendon, fat, endothelium, skeletal muscle, and cardiomyocytes. These findings raise the possibility that bone marrow-derived cells may provide an alternative source of cardiomyocytes in patients with severe cardiac failure due to loss of muscle cells. Some studies have indicated that locally or systemically delivered mesodermal stem cells can generate de novo cardiomyocytes. Despite their potential clinical utility for cellular and gene therapy, the mechanism of differentiation in mesodermal stem cells and characterization of stem cells in terms of surface antigen expression remain to be resolved. Although some clinical trials have been initiated using crude bone marrow-derived stromal cells, we need more knowledge of stem cells to establish a standard protocol for cellular therapy.

It has recently been reported that the human striatum, especially its ventral part, the nucleus accumbens, contains numerous neurons immunoreactive for aromatic L-amino acid decarboxylase (AADC; the second-step monoamine synthesizing enzyme), but not for tyrosine hydroxylase (TH; the first-step catecholamine synthesizing enzyme) or tryptophan hydroxylase (TPH; the first-step serotonin synthesizing enzyme). These AADC (+)/TH(-)/TPH(-) neurons are named D-neurons. AADC is also the rate-limiting synthesizing enzyme of phenylethylamine (PEA). Although the functions of striatal D-neurons are yet unclear, their functions were discussed in the present review based on recent findings in the literature. D-neurons may participate in the manifestation of efficacy of pharmacotherapy for Parkinson's disease by uptaking monoamine precursors, including L-dopa or droxidopa (L-threo-DOPS), and by converting them to dopamine (DA) or noradrenaline (NA), respectively. Because the nucleus accumbens is one of the brain regions involved in the pathogenesis of schizophrenia and drug dependence, D-neurons might be related to the etiology of these mental disorders. It has also been suggested that striatal D-neurons are the pluripotential cells that have compensating functions against aging or degeneration. Further studies should be conducted to elucidate the functions of this unique cell group in the human striatum.

In the acute phase of cerebral infarction, many experimental data suggest that free radicals including superoxide, hydroxy radical and nitric oxide are one of the most important factors to cause brain damage. We have clearly detected nitrotyrosine (a marker of endogenous production of peroxynitrite, which is readily produced from superoxide and nitric oxide) in neurons and intraparenchymal vascular walls during post-ischemic reperfusion. Free radical scavengers thus seem to be very promising tools of treatment, and one of them (edaravone) has recently been approved for clinical use in Japan. CREB (cyclic AMP response element binding protein) is a DNA-binding transcription factor, and its function is activated by phosphorylation of Ser133 residue. CREB plays important roles in neuronal development, synaptic plasticity and regeneration. We have found that phosphorylation of CREB is significantly and persistently increased in surviving neurons and oligodendrocytes in post-ischemic brain, while this phosphorylation is only transiently increased in neurons and oligodendrocytes which eventually die. These data suggest that CREB phosphorylation plays an important role in protection of ischemic brain tissue. Oligodendrocyte progenitor cells (OPC) remain abundant throughout the adult brain, and retain their ability to become not only mature oligodendrocytes, but also neurons. We have recently found that OPC are significantly activated and proliferate in the peri-infarct area at 1-2 weeks after ischemia, suggesting that OPC may be involved in the repair mechanisms of ischemic brain. Future targets of stroke treatment should include enhancement of intrinsic protection mechanisms such as CREB phosphorylation and activation of progenitors cells.

Neural stem cells (NSCs) are multipotential progenitor cells that have self-renewal activities. A single NSC is capable of generating various kinds of cells within the CNS, including neurons, astrocytes, and oligodendrocytes. Because of these characteristics, there is an increasing interest in NSCs and neural progenitor cells from the aspects of both basic developmental biology and therapeutic applications to the damaged brain. By understanding of nature of NSCs present in CNS, extracellular factors and signal transduction cascades involved in the differentiation and maintenance of NSCs, population dynamics and localizations of NSCs in embryonic and adult brains, prospective identification and isolation of NSCs, and induction of NSCs into particular neuronal phenotypes, which will be introduced in this review, it would be possible to develop a feasible strategy to manipulate cells in situ to treat the damaged brain.