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A Komiyama

Publications and source records attributed to A Komiyama.

At least 19 recordsLinked to original sources
PubMed1992

Progressive impairment of Schwann cell proliferation in vitro in murine globoid cell leukodystrophy (twitcher).

In an attempt to elucidate possible functional derangement in Schwann cells in globoid cell leukodystrophy (GLD), we investigated the proliferative capacity in vitro of Schwann cells from the twitcher (twi/twi), a murine model of human GLD, with thymidine autoradiography and cell counts. Regardless of genotype, Schwann cell numbers increased faster and initial thymidine incorporation was higher in suckling than in adult mice. Compared with cells from heterozygous (+/twi) or normal (+/+) mice, however, proliferative capacity of Schwann cells from twi/twi was depressed in both sucklings and adults. Reflecting in vivo activation secondary to demyelination, the number of labeled Schwann cells was transiently higher during the first 24 h in adult twi/twi cultures but the rate of proliferation declined thereafter and remained low during an 8 day period in culture. Our study demonstrates that proliferative capacity of twi/twi Schwann cells was impaired in vitro, possibly as a consequence of metabolic perturbation by a deficiency of galactosylceramidase.

Aging↗
PubMed1992

Stem cell factor enhances proliferation, but not maturation, of murine megakaryocytic progenitors in serum-free culture.

The effects of recombinant rat stem cell factor (SCF/c-kit ligand) on murine megakaryocytopoiesis were studied using partially purified bone marrow cells derived from normal and 5-fluorouracil (5-FU)-treated mice in a serum-free culture system. SCF alone did not support the formation of megakaryocyte (M) and granulocyte-macrophage-megakaryocyte (GMM) colonies. However, the addition of SCF to cultures containing interleukin-3 (IL-3) resulted in a significant increase in the number of M and GMM colonies formed by bone marrow cells from normal mice, whereas IL-6 augmented only M colony growth. The stimulatory effect of SCF was approximately three to four times as high as that of IL-6 on the primitive progenitors capable of megakaryocytic-lineage expression derived from 5-FU-treated mice. In addition, SCF, but not IL-6, significantly increased the number of constituent cells in the individual M colonies supported by IL-3. On the other hand, SCF did not exert any effect on the size and DNA content of megakaryocytes in IL-3-dependent M and GMM colonies, whereas IL-6 enhanced the maturation of megakaryocytes. These results suggest that SCF stimulates the proliferative process in megakaryocytic progenitors and that the main activity of IL-6 is the promotion of megakaryocyte maturation.

Animals↗
PubMed1992

Stimulation of mouse connective tissue-type mast cells by hemopoietic stem cell factor, a ligand for the c-kit receptor.

The proliferative capacity of mouse connective tissue-type mast cells (CTMC) was analyzed by using a newly discovered c-kit ligand, termed stem cell factor (SCF). More than 90% of CTMC in the peritoneal cavity responded to recombinant rat SCF (rrSCF) and were able to give rise to pure mast cell colonies in methylcellulose culture. Serial observation (mapping) of growth of individual CTMC in culture containing rrSCF confirmed their striking proliferative ability. No serum but accessory cells (non-CTMC cells) in the peritoneal population were required for the clonal growth of CTMC induced by rrSCF in our methylcellulose culture of whole peritoneal cells. The rrSCF-induced mast cell colony formation from peritoneal CTMC was completely inhibited by the addition of anti-c-kit antibody, which can block the binding of SCF to c-kit, to the culture. When IL-3 was combined with rrSCF, mast cell colonies dramatically increased in size. Mapping studies revealed that the combination of the two factors augmented the proliferative rate of CTMC. Approximately 60% of the constituent cells of the mast cell colonies which were formed from peritoneal CTMC in the culture containing rrSCF alone were stained with berberine sulfate, which is a characteristic of CTMC. However, most mast cells which were induced by rrSCF+IL-3 from peritoneal CTMC contained berberine(-)-safranin(-)-Alcian blue(+) granules. Although IL-4 exhibited little synergism with rrSCF in the induction of CTMC proliferation, the addition of IL-4 to the culture containing rrSCF+IL-3 resulted in an increase in mast cells which retained CTMC characteristics.

Animals↗
PubMed1992

Age-related differences in proliferative responses of Schwann cells during Wallerian degeneration.

Age-related differences in proliferative responses of Schwann cells during Wallerian degeneration were investigated in the mouse sciatic nerves after nerve-transection at 3, 10 and 60 days of age, corresponding to the periods of early myelination, active myelination and post-myelination. As assessed by thymidine incorporation for the first 24 h in culture, Schwann cells from adult nerve proliferated rapidly within day 1 post-transection and reached a peak at day 3. In the nerves from neonatal or suckling mice, however, division rate of Schwann cells declined after transection, and was even less in the transected nerves than in the contralateral uninjured nerves. The reduction in thymidine uptake by Schwann cells was more pronounced in nerves sectioned at postnatal day 3 than those sectioned at day 10. By contrast, fibroblasts divided rapidly following transection regardless of age. These data suggest that mitogens from myelin components are important for proliferation of Schwann cells and that in the degenerating nerves of young mice, mitotic capacity of Schwann cells declined due to not only a loss of axonal mitogens but also the paucity of mitogens from myelin components. Proliferation of fibroblasts is likely to be stimulated by more general growth-promoting polypeptides common to any other tissues during wound repair.

Aging↗
PubMed1992

Interferon-gamma inhibits proliferation, but not commitment, of murine granulocyte-macrophage progenitors.

We investigated the effects of interferon gamma (IFN-gamma) on the growth of murine hematopoietic progenitors. IFN-gamma inhibited granulocyte colony-stimulating factor (G-CSF)- and interleukin-3 (IL-3)-dependent colony growth by granulocyte-macrophage (GM) progenitors derived from the bone marrow cells of normal mice. However, the number of IL-3-dependent GM colonies formed by the bone marrow cells of 5-fluorouracil (5-FU)-treated mice was not influenced by the addition of IFN-gamma. Replating experiments suggested that IFN-gamma suppressed GM colony growth directly and that it exerted an inhibitory effect on the proliferation, but not on the commitment, of GM progenitors. In contrast, IFN-gamma failed to suppress colony growth by mast cell progenitors. Erythroid and megakaryocytic progenitors exhibited different responses to IFN-gamma depending on mouse strains. These results suggest that potent negative regulators are not always inhibitors of hematopoietic progenitors.

Animals↗
PubMed1992

Expression of the neu oncogene under the transcriptional control of the myelin basic protein gene in transgenic mice: generation of transformed glial cells.

We have taken a transgenic approach in an effort to specifically transform oligodendrocytes, the myelinating glial cells of the central nervous system (CNS). Transgenic mice were generated with a DNA construct that contained the activated neu oncogene under the transcriptional control of the myelin basic protein (MBP) gene. The MBP/c-neu transgenic animals have experienced a low incidence of brain tumors that express molecular markers specific to oligodendrocytes, providing a mouse model to study the formation and progression of oligodendrocyte tumors. A tumor from a transgenic animal has been dispersed in culture, and transformed cells that express properties of oligodendrocytes and astrocytes have been maintained. The degree to which these cells express phenotypic characteristic of oligodendrocytes or astrocytes is influenced by culture conditions. These transformed cells should serve as a valuable resource with which to study various molecular and biochemical aspects of the myelination process, as well as the lineage interrelationship of CNS glial cells.

Animals↗
PubMed1992

The twitcher mouse: immunocytochemical study of Ia expression in macrophages.

The cells expressing immune response associated antigen (Ia) were investigated in the nervous system of the twitcher mouse (an authentic murine model of globoid cell leukodystrophy in humans). With immunocytochemistry using a monoclonal antibody against Mac-1 antigen, many Mac-1 immunoreactive cells (Mac-1 positive cells) were detected in the central as well as the peripheral nervous systems (CNS and PNS). In the CNS, Mac-1 positive cells in the gray matter showed cellular morphology of ramified microglia with delicate cellular processes, while in the white matter Mac-1 positive cells were more plump in shape. Ia expressing cells (Ia positive cells) were also largely confined to the white matter. About 10% of the Mac-1 positive cells were Ia positive. The Ia and Mac-1 positive cells were slender and spindle shaped, and morphologically similar to Ia positive cells in the peripheral nerves while the cells expressing Mac-1 only were more plump in shape. With immunoelectron microscopy, however, both slender Ia positive and plump Ia negative and Mac-1 positive cells revealed electron lucent cytoplasmic vacuoles containing characteristic tubular inclusions of globoid cell leukodystrophy. The results suggest that Ia positive cells are a subset of macrophages in the CNS. Whether Ia expression was induced to "endogenous" microglia or whether Ia expressing cells were exogenous cells infiltrated in the CNS in response to pathological lesions is yet to be determined.

Animals↗
PubMed1992

T-cell-dependent production of IgG by human cord blood B cells in reconstituted SCID mice.

Reconstitution of severe combined immunodeficient (SCID) mice with human lymphocytes has recently allowed the elucidation of abnormalities of immune responses in various immunological disorders. In the present study, mononuclear cells (MNC) from neonatal cord blood and adult peripheral blood were intraperitoneally injected into SCID mice to examine induction of human Ig in respective mice recipients. Human IgG was consistently detected in the serum of SCID transferred with adult MNC, but only a few SCID recipients of cord blood MNC showed detectable but low levels of IgG in the serum. The combination experiments of isolated B and T cells disclosed that some interactions between B and T cells might be necessary for IgG production in transferred SCID mice. Notably, transfer of cord blood B cells with adult but not cord blood T cells resulted in efficient induction of IgG, associated with a change in subclass distribution. The results suggest that inability of neonatal B cells to produce IgG can be overcome by transfer with adult mature T cells into SCID mice.

Animals↗
PubMed1992

Ki-1 positive large cell anaplastic lymphoma: multiple bone lytic lesions and interleukin-6.

Ki-1-positive large cell anaplastic lymphoma (Ki-1 LCAL) is recognized as a clinicopathologic syndrome with fever, peripheral lymphadenopathy and cutaneous nodules; the neoplastic cells express Hodgkin's disease-associated antigen, Ki-1 (CD30). We review here a recent case of Ki-1 LCAL with multiple bone lesions with destruction and present additional information. Although bone absorption is reported in some cases of Ki-1 LCAL, the genesis of bone absorption is unclear. Interleukin-6 (IL-6) is an important regulator of osteoclast formation and activation and can induce bone absorption. In our case, the surgically removed tumor tissue was studied for IL-6 mRNA expression and IL-6 secretion without any stimulation. Northern blot analysis showed strong IL-6 mRNA expression in the tumor tissue and ELISA assay showed a large amount of IL-6 in culture supernatants of the tumor tissue. Based on these results, coupled with the reported evidence, we discuss the close relationship between the presence of osteolytic lesions and IL-6 production in Ki-1 LCAL.

Antigens, CD↗
PubMed1992

[Elevated production of GM-CSF by peripheral blood mononuclear cells stimulated with mite antigens in children with bronchial asthma].

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine which can stimulate the proliferation and functions of eosinophils and neutrophils. We have studied whether peripheral blood mononuclear cells (PBMC), obtained from children with stable asthma, can produce GM-CSF through stimulation with crude Dermatophagoides farinae (Df) antigen in vitro. The patients had strongly positive RAST results for house dust mite Df. Levels of GM-CSF in PBMC culture supernatant were assayed by an enzyme immunoassay. When stimulated with Df antigen, patient's PBMC released significantly increased levels of GM-CSF compared with unstimulated ones. PBMC of non-allergic controls, however, did not. The addition of polymyxin B, an inactivator of endotoxin, did not suppress the Df-antigen-induced production of GM-CSF. Levels of GM-CSF produced by PBMC stimulated with Df antigens were significantly higher in the patients than in the controls. These results indicate that PBMC of children with Df-allergic asthma, unlike those of non-allergic children, can produce elevated levels of GM-CSF by stimulation with Df antigens.

Animals↗
PubMed1992

[Action myoclonus in adult Huntington's disease].

In contrast to juvenile rigid form of Huntington's disease (HD) in which myoclonus is often seen, only 5 patients with myoclonus complicating adult HD have been reported. We herein described an adult HD patient who suffered from severe action myoclonus leading to physical disability. To our knowledge, this is the first case report in Japan. The patient, a 32-year-old female with a family history of chorea, developed choreiform movements and mental changes since the age of 24. Subsequently her motor disability has been aggravated by distinctively different involuntary movements characterized by sudden, violent, continuous muscular contractions of four extremities on any attempts at movement. Examination revealed moderate dementia and chorea complicated by frequent myoclonic jerks involving upper and lower extremities in posture or during movement. A head CT scan and MRI revealed caudate atrophy. The myoclonus, as recorded by surface electromyography over the right arm consisted of 40-60 msec-synchronous semirhythmic bursts. The cortical component of SEP was enlarged and C reflex was also observed. Clonazepam (4 mg a day) was instituted with a pronounced reduction in myoclonus and a return to her previous level of daily life activity. Although myoclonic jerks are often recognized in juvenile patients with rigid form of HD, they have been considered to exert a minor influence on physical disability. By contrast, our present observation and review of literature suggest that myoclonus may lead to severe motor impairment in adult HD.

Activities of Daily Living↗
PubMed1992

[Suppression of in vitro hemopoiesis by the monocytes in a patient with aplastic anemia associated with hepatitis].

The cause of aplastic anemia associated with hepatitis (AAH) is as yet still unknown. There is a supposed relation to the immune mechanisms, however few reports have shown the effects of monocytes on the pathogenesis in the patients with AAH. We have reported a case of a 12-year-old boy with AAH related to cytomegaloviruses, and studied the hemopoietic progenitors. He showed pancytopenia and hypoplasia of the bone marrow on admission to our hospital. The culture studies showed that mononuclear cells (MNC) of the bone marrow produced few hemopoietic colonies in all cell lineages. However, the depletion of adherent cells from the MNC increased numbers of erythroid, neutrophil-macrophage and megakaryocyte colonies. Furthermore, the addition of adherent cells of the peripheral blood suppressed the colony formation in the aforementioned cell lineages by marrow MNC from which adherent cells, phagocytic cells and T-cells were abrogated. The results way suggest that monocytes play some soles in the pathogenesis of aplasia through inhibitor of hemopoiesis.

Anemia, Aplastic↗
PubMed1991

Normal rate of Schwann cell proliferation in the MBP-deficient shiverer mouse during Wallerian degeneration.

Myelin basic protein (MBP) processed by macrophages was reported to promote Schwann cell division during Wallerian degeneration. In the present study we have shown that there was no difference in the rate of Schwann cell proliferation between shiverer mice, which totally lack MBP, and control mice after nerve-transection. Furthermore, addition of autologous peritoneal macrophages in cultures led to enhanced thymidine uptake by Schwann cells, irrespective of the presence or absence of MBP. These results suggest that myelin components other than MBP play a role in Schwann cell proliferation induced by macrophages.

Animals↗
PubMed1991

Age-related changes in attachment and proliferation of mouse Schwann cells in vitro.

Schwann cells can be cultured readily from the peripheral nerves of the neonatal animal but not from the adult. To correlate the physiological properties of Schwann cells relevant to such a difference, we examined age-related changes in attachment and proliferation of mouse Schwann cells in vitro. The capacity of Schwann cells to attach to polylysine-coated coverslips at 1 day in vitro declined rapidly between 3 and 30 days of age, followed by a more gradual decrease with age. Attachment of Schwann cells from younger mice (but not older mice) was enhanced by precoating coverslips with laminin or to a lesser degree with fibronectin, suggesting an age-dependent decrease in receptors for these substrates. Indeed, the staining for fibronectin receptor could be demonstrated in vivo, and was more intense and diffuse in neonatal sciatic nerves. In vitro, although staining of Schwann cells and fibroblasts was clear, there was no age-related difference for the intensity or distribution of the staining. Proliferation, as assessed by thymidine incorporation at 1 day in vitro, was high when Schwann cells were isolated from younger mice but declined as a function of the age of mice from which cells were prepared. Removal of axonal and myelin debris from cultures 3 h after plating resulted in a reduction of thymidine uptake by Schwann cells from 30-day-old mice, but much less from 10-day-old mice. Schwann cell growth was faster in the cells from younger mice than older ones, thus leading to early confluency and cell-contact inhibition in the former. In addition, evidence is presented that in medium supplemented with fetal bovine serum, thymidine uptake by Schwann cells from mice at 3-30 days of age was three times higher than that by Schwann cells from age-matched rats. These results indicate that the methodology usually used for purification of rat Schwann cells involving antimitotics is not suitable for highly proliferating mouse Schwann cells.

Aging↗
PubMed1991

Functional p75 interleukin-2 receptor expression on the fresh blast cells in childhood acute lymphoblastic leukemia with natural killer cell properties.

Neoplastic cells of childhood acute lymphoblastic leukemia (ALL) with natural killer (NK) cell properties were studied for the expression of p75 interleukin-2 receptors (IL-2R) and the receptor functions. Freshly prepared blast cells from a patient with ALL had NK cell properties: (1) the phenotype such as CD56+, CD2+, E-rosette+, CD3-, and CD19-; and (2) the presence of spontaneous cytotoxicity against NK-sensitive K562 target cells. Although p55 Tac antigen was not detectable, there was the expression of p75 IL-2R on the freshly prepared blast cells: 70% of the cells reacted with Mik-beta 1 monoclonal antibody against p75 IL-2R as determined by flow cytometry. Two-color flow cytometry revealed that the blast cells expressed both p75 IL-2R and NKH-1. NK activity of the blast cells was augmented by their treatment with 1,000 U/ml recombinant IL-2 (rIL-2): the cytotoxicity level as percentage lysis increased to 38.7% from 22.0% when the normal lymphocyte value increased to 62.1% from 46.2%. Although the blast cells possessed no apparent level of proliferative capacity, the addition of 1,000 U/ml rIL-2 yielded a 2.7-fold increase in their thymidine uptake. These results demonstrate the expression of functional p75 IL-2R on the patient's blast cells with NK cell properties.

Adolescent↗
PubMed1991

Adhesion and proliferation are enhanced in vitro in Schwann cells from nerve undergoing Wallerian degeneration.

Proliferation of Schwann cells during nerve degeneration or regeneration is well documented in vivo. We investigated whether the proliferative response of Schwann cells to injury is retained in vitro. Using 5-month-old male C57BL mice, Schwann cells were isolated from sciatic nerves under 3 experimental conditions: (1) uninjured, (2) after permanent nerve-transection, or (3) after nerve-crush, which permits axonal regeneration. Schwann cells rarely attached to polylysine-coated coverslips when isolated from uninjured or 1 day posttransection/crush nerves. The number of adherent cells increased when Schwann cells were isolated 3 days after nerve-transection or -crush. When cells were isolated from transected nerves, cell adhesion reached a peak 2 weeks after the injury and then declined. Maximal attachment of Schwann cells occurred when the cells were isolated 2-4 weeks after nerve-crush. The percentage of Schwann cells with spreading processes corresponded closely with the number of thymidine-labeled cells at 1 day in vitro. The in vitro capacity of cells to spread and incorporate thymidine reached maximal levels at 5 days posttransection/crush. Capacity of cells to spread and incorporate thymidine subsequently decreased with time following transection. However, a biphasic elevation in cell spreading and thymidine incorporation was observed in Schwann cells isolated from crushed nerves. Maximal growth of Schwann cells in vitro occurred at 1-2 weeks posttransection and at 1-4 weeks postcrush. Adhesion and spreading of Schwann cells were promoted by coating coverslips with laminin or fibronectin. Preincubation of Schwann cells with soluble laminin or fibronectin prevented the initial cell attachment induced by the corresponding protein. Our results suggest that Schwann cells from injured nerves possess binding sites for laminin and fibronectin, which are, in part, responsible for the enhanced adhesion of Schwann cells in vitro. This study provides a new method for preparation of Schwann cells from peripheral nerves of adult mice.

Animals↗