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Biomedical subjects

M Tomonaga

Publications and source records attributed to M Tomonaga.

At least 145 records · Page 8Linked to original sources
PubMed1997

The clinical significance of cerebral veins in moyamoya disease.

A total of 11 patients with Moyamoya disease who underwent digital subtraction angiography were studied with respect to the cerebral venous system. First, delayed venous filling and the divisional change of the superficial cerebral veins have been attributed to the development of collateral pathways in Moyamoya disease and may be reflective appearances for the pathophysiological conditions in Moyamoya disease. Particularly, delayed venous filling may be an important finding which predicts an ischemic attack. Secondarily, the inferior striate veins were frequently detected in proportion to the development of Moyamoya vessels. On the other hand, the superior striate veins were prominent in the decrement stage of Moyamoya vessels. These findings may give support to the pathological findings of Moyamoya vessels that there were observed various degrees of dilatation with venous-like vessels as well as dilated perforating arteries.

Adolescent↗
PubMed1997

Morphological subtyping of acute myeloid leukemia with maturation (AML-M2): homogeneous pink-colored cytoplasm of mature neutrophils is most characteristic of AML-M2 with t(8;21).

Morphologic and cytochemical features of 30 acute myeloid leukemia subtype M2 (AML-M2) patients with t(8;21) were compared with those of 50 AML-M2 patients without t(8;21). It was disclosed that irregular nuclear shape, Auer bodies, and at least 90% myeloperoxidase positivity in blast cells, and pseudo-Pelger-Huët anomaly of the nuclei and homogeneous pink-colored cytoplasm of mature neutrophils were observed in 90-100% of the t(8;21)+ patients. The percentages of patients showing these features were significantly (P < 0.01) lower in the t(8;21)- group. Among these morphological features, homogeneous pink-colored cytoplasm of mature neutrophils is most characteristic of t(8;21)+ AML-M2, because it was seen in 90% of the t(8;21)+ patients but in only 2% of the t(8;21)- patients. Conversely, pale-colored cytoplasm without any granules in mature neutrophils or dyserythropoietic features was observed in 84% of the t(8;21)- patients, but in none of the t(8;21)+ patients. These data suggest that it is possible to subtype AML-M2 patients morphologically by the recognition of homogeneous pink-colored or pale-colored cytoplasm of mature neutrophils and dyserythropoietic features. Thus, the morphologic subtyping of AML-M2 can be utilized alone or in combination with chromosomal or molecular subtyping for biological and clinical studies of AML with maturation.

Adolescent↗
PubMed1997

Extensive analysis of the retinoblastoma gene in adult T cell leukemia/lymphoma (ATL).

The retinoblastoma susceptibility gene (Rb) plays a key role in regulating the cell cycle in association with cyclins and cyclin-dependent kinases (CDKs). Alteration of the Rb gene as well as CDK inhibitors (CDKIs) leads to deregulated cellular growth which promotes cancer formation. We examined the genomic configuration of the entire Rb gene in 40 primary adult T cell leukemias/lymphomas (ATL) and two ATL cell lines by Southern blotting and also by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analyses. Homozygous loss of exon 1 was identified in one of 21 acute ATL, one of 15 chronic ATL, and none of four lymphomatous ATL samples. No point mutations were identified. Previously, we found that 10 of these same ATL samples had alterations of either p16(INK4A) (homozygous deletion) or p27(kip1) (homozygous deletion or point mutation). Although the numbers are very low, none of the samples with an aberrant Rb gene had an altered CDKI and vice versa, suggesting that both genes probably operate in a common pathway and alteration of either can provide these cells with a growth advantage.

Carrier Proteins↗
PubMed1997

Establishment and characterization of a new erythropoietin-dependent acute myeloid leukemia cell line, AS-E2.

We have established an erythropoietin-dependent human leukemia cell line, AS-E2, from a patient with acute myeloid leukemia. These cells have many characteristics of late erythroid progenitor cells, they are positive for CD36, Glycophorin A, and CD71 but negative for CD41, and positive for benzidine and PAS staining. These cells express GATA-1 and have low affinity erythropoietin (EPO) receptor on their surface. Interestingly, AS-E2 cells are strictly dependent on EPO for their growth and survival; other cytokines including GM-CSF, stem cell factor, or IL-3 cannot support the growth of this cell line. These features are similar to late erythroid lineage cells, like normal BFU-E or CFU-E, and we have demonstrated that EPO stimulation induces the tyrosine phosphorylation of several proteins in AS-E2 cells including the EPO receptor and JAK2 kinase. This new cell line is a useful reagent to study biological and molecular events during the late stages of erythropoiesis, and to understand transforming events in human erythroid cells.

Acute Disease↗
PubMed1997

Expression of CD8beta and alteration of cell surface phenotype in adult T-cell leukaemia cells.

Typical adult T-cell leukaemia (ATL) cells have a CD4+ CD8- cell surface phenotype, but atypical phenotypes such as CD4+ CD8+ and CD4- CD8+ have also been reported. The CD8 molecule is composed of alpha and beta chains and commonly used monoclonal antibodies against CD8 molecule detect only CD8alpha. Since it has been reported that CD8alpha can be induced in mature CD4+ T cells by cell activation, but not CD8beta, we studied whether ATL cells which express CD8alpha may also express CD8beta. We found some cases of CD8alpha+ ATL were also positive for CD8beta. Furthermore, we experienced a case whose ATL cell surface phenotype changed from CD4+ CD8alpha+ CD8beta+ to CD4- CD8alpha+ CD8beta+ and finally to CD4+ CD8alpha- CD8beta-. Southern blot analysis revealed that the monoclonal integration of human T lymphotropic virus type I (HTLV-I) was identical throughout the course of the study, indicating that a single clone had demonstrated the alterations. These data suggest that peripheral CD4+ CD8+ ATL cells can express not only CD8alpha, but also CD8beta and that a single ATL cell clone has the potential to change its surface phenotype in vivo as well as in vitro.

Adult↗
PubMed1997

Analysis of p18INK4C in adult T-cell leukaemia and non-Hodgkin's lymphoma.

p18INK4C, a cyclin-dependent kinase inhibitor, is a homologue of p15INK4B and p16INK4A which are frequently altered in a variety of malignancies. We searched for structural alterations of the p18INK4C gene in 44 adult T-cell leukaemias (ATLs), 101 non-Hodgkin's lymphomas (NHLs), two polyclonal B-cell proliferations, seven ATL cell lines and seven leukaemia/lymphoma cell lines, by Southern blot and polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analyses. No genomic alterations of the p18INK4C gene were found in any of the samples. By RT-PCR, p18INK4C was not expressed in three of five ATL cell lines, whereas it was expressed in all the non-ATL leukaemia/lymphoma cell lines. Tax did not inhibit the expression of p18INK4C in tax-expressing Jurkat cells.

Adult↗
PubMed1997

Quantitative characterization and potential function of membrane Fas/APO-1 (CD95) receptors on leukaemic cells from chronic B and T lymphoid leukaemias.

The expression and function of the Fas-receptor (Fas-R) were examined in chronic lymphocytic leukaemia (CLL), hairy cell leukaemia-variant (HCL-v) and adult T-cell leukaemia (ATL). The expression of Fas-R in freshly isolated leukaemic cells was qualitatively and quantitatively different between each disease; faint in B-CLL, moderate in HCL-v and strong in ATL. Both full-length and alternatively spliced truncated forms of Fas mRNA were detected even in CLL B cells with faint to negative Fas-R, and Fas mRNA was also shown to be capable of increasing in vitro expression, i.e. the message was functional. In contrast, Fas-R expression on ATL cells was heterogenous and usually intense with a mean density approximately 3-fold higher than that of normal T cells. Fas-R was confirmed to have the potential function for anti-Fas monoclonal antibody-mediated cell death in vitro in Fas-R+ ATL cells. The expression level of Fas-R on the cells was higher in chronic than acute ATL (10,360 v 6260 antibody-binding capacity per cell, mFasABC; P<0.05) and was inversely correlated with serum LDH activity, suggesting that the strong Fas-R accounts for the slow progression of chronic ATL and the negative Fas-R protects from Fas-mediated cell death. These results show that Fas-R expression on leukaemic cells is valuable in their characterization and perhaps their function, and may contribute to the progression and immune evasion of malignant clones.

Apoptosis↗
PubMed1997

Flexible neuroendoscopy for percutaneous treatment of intraventricular lesions in the absence of hydrocephalus.

A procedure with a flexible fiberoptic neuroendoscope was applied to a series of patients with small lesions in the lateral ventricle, not associated with hydrocephalus. The maneuverability of the flexible neuroendoscope allows the surgeon to work in narrow spaces of the lateral ventricle avoiding surgical trauma to surrounding neural structures. The safety and accuracy of this procedure depend upon how available working space is obtained in the undilated ventricles. Both shaft-rotation and tip-flexion of the flexible neuroendoscope are available for adjusting it to the wider axis in each region of the lateral ventricle and for dealing with the intraventricular lesions. Three patients with a small intraventricular lesion, two with arachnoid cysts and one with subependymal hematoma, underwent such a procedure successfully. It is concluded that this neuroendoscopic procedure provides benefits to the treatment of small intraventricular lesions regardless of the size of the cerebral ventricles.

Adult↗
PubMed1997

Successful treatment with cyclosporine in a case of hemophagocytic syndrome manifesting as severe liver dysfunction.

Forms of hemophagocytic syndrome, which affects mainly children, vary from mild to very severe and often fatal. We describe an adult patient with hemophagocytic syndrome in whom severe liver dysfunction developed. The condition continued to deteriorate despite treatment with plasma exchange, high-dose gamma globulin, and corticosteroid therapy. Treatment with cyclosporine (2.3 mg/kg/day) dramatically improved the condition and normalized liver function. Cyclosporine reduced the serum levels of ferritin, interferon-tau, interleukin-6, and soluble interleukin-2 receptor. These findings suggest that hemophagocytic syndrome accompanied with severe liver dysfunction results from hypercytokinemia, and cyclosporine is useful in preventing a fatal outcome during the acute phase.

Adult↗
PubMed1997

Cerebral blood flow and autoregulation in normal pressure hydrocephalus.

OBJECTIVE: We tried to identify indications for cerebrospinal fluid shunting in patients with normal pressure hydrocephalus. METHODS: We studied the cerebral blood flow (CBF) and vascular response to acetazolamide in the white matter, cortex, and thalamus of 21 patients with normal pressure hydrocephalus, comparing patients who improved clinically after shunting with those who did not. We used xenon-enhanced computed tomography for the CBF measurements. RESULTS: Preoperatively, both groups had globally reduced CBF, but the reduction was more pronounced in the unimproved patients. The vascular response was impaired only in the white matter of the patients who improved later. After shunting, restoration of CBF, more marked in the white matter, and recovery of vascular response in the white matter paralleled clinical improvement and a reduction in ventricular dilation and periventricular lucency on computed tomographic scans in nine patients. The CBF reduction, however, deteriorated in the 12 patients who did not improve clinically. CONCLUSION: We conclude that the underlying disease in the improved patients was ischemia, with a loss of autoregulatory capacity in the periventricular white matter caused by cerebrospinal fluid diffusion. Those who did not improve had irreversible brain damage in which the CBF reduction was secondary to metabolic depression and autoregulation was preserved. We also conclude that patients suspected of having normal pressure hydrocephalus will improve clinically after shunting if preoperative hemispheric CBF is greater than 20 ml/100 g per minute and the vascular response to acetazolamide is impaired only in the periventricular white matter. They will not improve, however, if the preoperative CBF is less than 20 ml/100 g per minute and the vascular response to acetazolamide is intact.

Aged↗
PubMed1997

In vivo retrovirus-mediated herpes simplex virus thymidine kinase gene therapy approach for adult T cell leukemia in a rat model.

We have previously demonstrated that human T-lymphotropic virus type I (HTLV-I) tax-expressing human T cell lines are selectively eliminated in the presence of aciclovir, using a retroviral vector carrying the herpes simplex virus thymidine kinase (HSV TK) gene under the control of the long terminal repeat (LTR) of HTLV-I. Based on these findings in vitro, we investigated whether this system could also be effective in vivo, using a rat model. Following infection of the HTLV-I-transformed and tax-expressing rat T cell line TARS-1 with this retrovirus (LNLTK virus), high levels of HSV TK expression were observed and resulted in increased susceptibility to ganciclovir (GCV). Tumors were generated by subcutaneous injection of TARS-1 in newborn syngeneic WKA/H rats. While the tumors derived from infected TARS-1 cells with control virus, as well as uninfected cells, continued to grow in all the rats with or without administration of GCV, those derived from LNLTK-infected cells exhibited dramatic regression upon GCV treatment. These results indicate that the HTLV-I LTR-HSV TK system also causes selective elimination of HTLV-I-transformed, tax-expressing T cells in vivo. Therefore, our present study may provide a rationale for clinical gene therapy against adult T cell leukemia.

Animals↗
PubMed1997

Treatment of the anemia of aplastic anemia patients with recombinant human erythropoietin in combination with granulocyte colony-stimulating factor: a multicenter randomized controlled study. Multicenter Study Group.

A multicenter randomized controlled study was undertaken in order to determine whether epoetin beta (EPO) ameliorates the anemia in aplastic anemia (AA) patients treated with granulocyte colony-stimulating factor (G-CSF). Enrolled patients were randomized into 3 groups: group C receiving G-CSF alone as the control; group L receiving G-CSF and 200 IU/kg of EPO; group H receiving G-CSF and 400 IU/kg of EPO. Throughout the study, the dose and the administration interval of G-CSF were adjusted to maintain neutrophil counts between 1000 and 5000 microliters EPO was administered subcutaneously for 12 wk as the first step in treatment and when favorable effects were observed over this period, treatment was continued for another 12 wk as the second step in treatment. Significant erythroid responses were defined as increases in untransfused hemoglobin values > 1.0 g/dl or > 50% decreases in RBC transfusion requirements over the treatment period. Of 131 patients enrolled, 88 patients allocated to groups L and H were evaluated for toxicity to EPO and 110 were evaluated for erythroid responses. Four of the 31 patients (12.9%) in group C, 6 of the 41 patients (14.6%) of group L, and 14 of the 38 patients (36.8%) of group H showed erythroid responses in the first step in treatment. The erythroid responses of group H were significantly higher than those of the other 2 groups (p < 0.05). The significant effects of EPO were due to erythroid responses in non-severe AA. Responding patients were significantly different from non-responders with regard to disease severity, hemoglobin concentration, reticulocyte count, serum endogenous erythropoietin levels and serum transferrin receptors; non-severe AA patients were more likely to respond to EPO, and responding patients had lower serum EPO and higher hemoglobin concentration, reticulocyte count and serum transferrin receptors than non-responders. The response rate increased in the second step in treatment, suggesting that long-term treatment improved the efficacy of EPO. No serious side-effects were observed. From these results, we conclude that EPO given in combination with G-CSF is a safe and effective alternative for the treatment of anemia of a subset of AA patients.

Adult↗
PubMed1997

The activation of the JAK2/STAT5 pathway is commonly involved in signaling through the human IL-5 receptor.

The JAK (Janus kinase) family of protein tyrosine kinases and the STATs (signal transducers and activators of transcription) have been shown to be activated in response to a number of cytokines and growth factors. In this study, we evaluated the activation of JAK/STAT pathway upon human interleukin-5 (hIL-5) stimulation of two different hIL-5-responsive cell lines, hIL-5 receptor alpha-subunit (hIL-5R alpha) cDNA-transfected TF-1 (TF-h5R alpha) and butyric-acid-treated YY-1 (YY-Bu), and peripheral eosinophils. Immunoprecipitation and electrophoretic mobility shift analysis revealed that tyrosine phosphorylation of JAK2 and activation of STAT5 were induced upon stimulation with hIL-5 in all three cell types, while STAT1 activation was only observed in eosinophils. These results indicate that JAK2/STAT5 activation is a common JAK/STAT pathway for hIL-5-mediated signal in these cells.

Cell Line↗
PubMed1997

Deletions of p15 and/or p16 genes as a poor-prognosis factor in adult T-cell leukemia.

PURPOSE: To determine the frequency of the deletions of p15/p16 genes in adult T-cell leukemia (ATL) cells and to evaluate their value in the diagnosis of clinical subtypes of ATL patients and the prediction of their clinical outcome. MATERIALS AND METHODS: Peripheral-blood samples from 114 patients with ATL were examined by Southern blot analysis. In five chronic-type patients who showed disease progression to acute type, serial samples also were examined. RESULTS: Among 114 patients, 28 (24.6%) showed the deletions of p15 and/or p16 genes. The results were well correlated with the clinical subtypes. Patients with deleted p15 and/or p16 genes had significantly shorter survival times than the patients in whom both genes were preserved (P < .0001). A similar decline in survival time was observed in the analyses within the same subtypes. In multivariate analysis using the Cox proportional hazard model, the deletions of p15 and/or p16 genes emerged as an independent prognostic indicator. Moreover, three of the five chronic-type patients who progressed to acute type lost the p16 gene alone or both the p15 and p16 genes at their exacerbation phase. CONCLUSION: The results suggest the following: (1) that the deletions of p15 and/or p16 genes play a key role in the progression of ATL; and (2) that these deletions are reliable prognostic factors that predict shortened survival times.

Adult↗
PubMed1997

Human urinary macrophage colony-stimulating factor reduces the incidence and duration of febrile neutropenia and shortens the period required to finish three courses of intensive consolidation therapy in acute myeloid leukemia: a double-blind controlled study.

PURPOSE: To determine whether macrophage colony-stimulating factor (M-CSF) reduces the incidence and duration of febrile neutropenia during three courses of intensive consolidation therapy and whether it shortens time to complete consolidation therapy. PATIENTS AND METHODS: In 198 adult patients with acute myeloid leukemia (AML) in complete remission (CR), M-CSF (8 x 10(6) U/d) or placebo was administered from 1 day after the end of each consolidation chemotherapy for 14 days. RESULTS: The duration and incidence of febrile neutropenia was significantly reduced by 34% (P = .00285) and 17% (P = .02065), respectively, in 88 assessable patients in the M-CSF group compared with those in 94 assessable patients in the placebo group. Patients in the M-CSF group had 565 days and 133 episodes of febrile neutropenia during 7,901 days at risk, while patients in the placebo group had 977 days and 185 episodes during 9,077 days at risk. The median period required to finish the three courses of consolidation therapy was 93 days in the M-CSF group, which was significantly shorter than 110 days in placebo group (P = .0050). In the M-CSF group, the recovery of neutrophils and platelets was significantly faster (P = .0348 and P = 0.0364, respectively), the administration of systemic antimicrobial agents tended to be less (P = .0839), and the frequency of platelet transfusion (P = .0259) and the total volume of transfused platelets (P = .0292) were significantly less. However, there was no significant difference in the disease-free survival. CONCLUSION: M-CSF significantly reduced the incidence and duration of febrile neutropenia during the intensive consolidation therapy, and shortened the time to complete consolidation chemotherapy in AML.

Acute Disease↗
PubMed1997

Serum levels of soluble Fas/APO-1 receptor in human retroviral infection and associated diseases.

Fas/APO-1 mediates apoptosis via Fas and Fas ligand transduction. Recently, a soluble form of Fas (sFas) was described which seems to be functionally implicated in the Fas signal system, suggesting a relationship between some disorders and sFas function. We measured sFas-levels in sera from normal controls and patients with disorders linked to human retroviral infection of human immunodeficiency virus (HIV) and human T-cell leukemia virus type-1 (HTLV-1). The sFas level of normal controls. HTLV-1 carriers seronegative for HIV, and patients with HTLV-1 associated myelopathy/tropical paraparesis (HAM/TSP), adult T-cell leukemia (ATL), and AIDS was 1.62 +/- 0.49, 1.90 +/- 0.49, 2.00 +/- 0.59, 3.32 +/- 2.05, and 3.06 +/- 0.92 ng/ml, respectively. Although the level of sFas in patient groups with HAM/TSP, ATL, and AIDS was significantly high in comparison to that of normal controls (p < 0.01), the individual values were highly variable within the groups. The sFas level was statistically correlated to the soluble interleukin-2 receptor (sIL-2R) level, as well as to cells expressing membrane Fas (mFas), indicating the same cellular origin. In some ATL cases, however, serum sFas levels and mFas expression density on leukemic T-cells were discrepant, with especially high levels of the soluble form and a lack of expression of the membrane form observed in 2 cases, sFas detection could serve as a putative marker for active diseases in patients with ATL and AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Cerebellar gliomas with exophytic growth--three case reports.

Three patients presented with cerebellar hemispheric astrocytic tumors which showed an exophytic growth pattern. The neuroimaging appearances of these cases mimicked a cerebellopontine angle tumor in two cases, and a posterior fossa extra-axial tumor in the other, which arose from the left cerebellar hemisphere with exophytic extension into the left crural and quadrigeminal cisterns and compressed the midbrain directly. All patients underwent surgical resection, and two patients also received adjuvant radiation therapy and chemotherapy. Intraoperative findings confirmed that the tumors had intramedullary origins from the cerebellar hemisphere, and extended exophytically into the subarachnoid space forming an extra-axial mass lesion. The histological diagnoses were mixed malignant oligo-astrocytoma (grade III), astrocytoma (grade II), and glioblastoma (grade IV). Cerebellar gliomas with exophytic growth to the cerebellopontine angle cistern should be considered in the differential diagnosis of cerebellopontine angle tumors.

Aged↗