Biomedical subjects

M Sakurai

Publications and source records attributed to M Sakurai.

At least 217 records · Page 12Linked to original sources

PubMed1997

Minimal residual disease in acute monocytic leukemia patient with trisomy 11 and partial tandem duplication of MLL.

We studied MLL rearrangements in five patients with myeloid hematologic malignancies with trisomy 11. Two had acute monocytic leukemia (AMoL), one had chronic myelomonocytic leukemia, one had refractory anemia, and the other had juvenile chronic myelogenous leukemia. Only one patient, a 15-year-old boy with AMoL and simple trisomy 11, showed rearrangement of MLL. He did not respond to chemotherapy, and successfully underwent bone marrow transplantation, but suffered a relapse 22 months later. Reverse transcription-polymerase chain reaction (RT-PCR) and sequencing analyses of bone marrow cells revealed a tandem duplication of MLL, and his relapse was predictable by sequential RT-PCR studies before it was clinically evident. Of 16 acute myeloid leukemia patients with trisomy 11 and rearrangement of MLL reported, our patient was the youngest in age and the only one with AMoL.

Adolescent↗

PubMed1997

In vitro drug sensitivity testing can predict induction failure and early relapse of childhood acute lymphoblastic leukemia.

It is vital to develop effective therapy for children with acute lymphoblastic leukemia (ALL), in whom no remission occurs or who suffer relapse with current protocols. Cellular drug resistance is thought to be an important cause of induction failure and relapse. We performed in vitro tests of bone marrow samples in 196 children with newly diagnosed ALL with a 4-day culture and a methyl-thiazol-tetrazolium assay. We tested 16 drugs and calculated the 70% lethal dose (LD70) for 14 drugs and the leukemic cell survival (LCS) rate for dexamethasone and prednisolone. For each single drug, patients were classified into two groups, sensitive or resistant, by median concentration of LD70 or LCS. When patients were classified into three groups by sensitivity to four drugs of DPAV (dexamethasone, prednisolone, L-asparaginase, and vincristine), 3-year event-free survival (EFS; 95% confidence intervals) of the super sensitive group (SS; sensitive to all 4 drugs) was 0.833 (0.690 to 0.976), that of the intermediate sensitive group (IS; sensitive to 2 or 3 drugs) was 0.735 (0.609 to 0.863), and that of the relatively resistant group (RR; sensitive to no drugs or to 1 drug) was 0.541 (0.411 to 0.670; P = .0008). We then investigated the relationship between the above four-drug sensitivity and the time of relapse. The SS and IS patients tended to maintain continuous complete remission, and RR patients tended to undergo induction failure and early and late relapse (P = .004). Initial white blood cell count, immunologic classification, and age were also predictive factors, but the patient numbers showed no statistical correlation between these factors and the four-drug sensitivity groups (SS, IS, and RR). When we took three groups SS/IS/RR and investigated the EFS for various clinical groups, DPAV sensitivity strongly influenced EFS in the standard-risk ALL (P = .016). In vitro drug sensitivity testing provides additional prognostic information about childhood ALL, and early detection of drug resistance at the time chemotherapy commences may provide a successful strategy for individualizing treatment, as the results indicate de novo resistance to front-line drugs and suggest alternative, second-line drugs.

Aclarubicin↗

PubMed1997

Role of acute cochlear neuritis in sudden hearing loss in multiple sclerosis.

We report a patient with definite multiple sclerosis (MS) who developed unilateral sudden hearing loss coincident with exacerbation of central nervous system symptoms. Involvement of the peripheral cochlear nerve, suggested by auditory findings including auditory brainstem response, was confirmed by magnetic resonance imaging. The clinical, electrophysiological and neuroradiological abnormalities disappeared in response to steroid pulse therapy. These findings suggest that acute inflammatory demyelinative lesion of the peripheral cochlear nerve can occur in MS, manifesting sudden hearing loss.

Acute Disease↗

PubMed1997

Hematologic malignancies with the t(10;11) (p13;q21) have the same molecular event and a variety of morphologic or immunologic phenotypes.

Previous studies described the t(10;11)(p13-14;q14-21) as a recurring translocation associated with T-cell acute lymphoblastic leukemia (ALL). This translocation has also been reported in monocytic leukemia or ALL with a very early pre-B phenotype. However, whether these cytogenetically similar translocations involve the same molecular breakpoint is unknown. Using fluorescence in situ hybridization (FISH) with a series of probes on 11q, we mapped the 11q breakpoint of the U937 cell line, which was derived from a patient with diffuse histiocytic lymphoma and was shown by FISH to have the t(10;11)(p13-14;q14-21). Subsequently, we identified a yeast artificial chromosome (YAC) clone, y960g8, that included the breakpoint on 11q. From this YAC, we isolated a PI clone, P91B1, that was split by the 10;11 translocation. We studied four patients with a t(10;11), one of whom had acute monocytic leukemia (AMoL), one had acute lymphoblastic leukemia (ALL), one had lymphoblastic lymphoma (LBL), and one had granulocytic sarcoma, by using FISH with y960g8 and P91B1. Y960g8 and P91B1 were split by the translocation in each patient. We showed that P91B1 included a recently identified gene, CALM (Clathrin Assembly Lymphoid Myeloid leukemia gene), and that AF10 was also rearranged in each patient by FISH when we used y807b3, which contains the AF10 gene. These findings indicate that hematologic malignant diseases with fusion of AF10 and CALM show various morphologic and immunologic phenotypes, suggesting that this fusion occurs in multipotential or very early precursor cells.

Adult↗

PubMed1997

The developmental origin of primordial germ cells and the transmission of the donor-derived gametes in mixed-sex germline chimeras to the offspring in the chicken.

A novel system has been developed to determine the origin and development of primordial germ cells (PGCs) in avian embryos directly. Approximately 700 cells were removed from the center of the area pellucida, the outer of the area pellucida, and the area opaca of the stage X blastoderm (Eyal-Giladi and Kochav, 1976; Dev Biol 49:321-337). When the cells were removed from the center of the area pellucida, the mean number of circulating PGCs per 1 microliter of blood was significantly decreased to 13 (P < 0.05) in the embryo at stage 15 (Hamburger and Hamilton, 1951: J Morphol 88:49-92) as compared to intact embryos of 51. When the removed recipient cells from the center of the area pellucida were replenished with 500 donor cells, no reduction in the PGC number was observed. The removal of cells from the outer of area pellucida or from the area opaca had no effect on the number of PGCs. When another set of the manipulated embryos were cultured ex vivo to hatching and reared to sexual maturity, the absence of germ cells and the degeneration of seminiferous tubules were observed in resulting chickens derived from the blastoderm from which the cells were removed from the center of the area pellucida. Chimeric embryos produced by the male donor cells and the female recipient contained the female-derived cells at 97.2% in the whole embryo and 94.3% in the erythrocytes at 5 days of incubation. At 5-7 days of incubation, masculinization was observed in about one half of the mixed-sex embryos. The proportions of the female-derived cells in the whole embryo and in the erythrocytes were 76.5% and 80.2% at 7 days to 55.7% and 62.5% at 10 days of incubation, respectively. When the chimeras reached their sexual maturity, they were test mated to assess donor contribution to their germline. Five of six male chimeras (83%) and three of five female chimeras (60%) from male donor cells and a female recipient embryo from which 700 cells at the center of area pellucida were removed were germline chimeras. Three of the five male germline chimeras (60%) and one of the three female germline chimeras (33%) transmitted exclusively (100%) donor-derived gametes into the offspring. When embryonic cells were removed from the outer of area pellucida or area opaca, regardless of the sex combination of the donor and the recipient, the transmission of the donor-derived gametes was essentially null. The findings in the present studies demonstrated, both in vivo and in vitro, that the PGCs originate in the central part of the area pellucida and that the developmental fate to germ cell (PGCs) had been destined at stage X blastoderm in chickens.

Animals↗

PubMed1997

Changes in intracellular cytokine levels in lymphocytes induced by measles virus.

We investigated the changes in intracellular cytokine levels in different lymphocyte populations induced by measles virus (MV). MV-infected and uninfected peripheral blood mononuclear cells were cultured with phorbol 2-myristate 13-acetate plus ionomycin in the presence of monensin for 10 hr. Surface antigen and intracellular cytokines, interleukin (IL)-2, interferon (IFN)-gamma, and IL-4, were stained simultaneously and analyzed by flow cytometry. The percentage of cells that expressed IL-2 and IFN-gamma was significantly increased in MV-infected CD3+, CD4+, and CD8+ lymphocytes and alphabeta T lymphocytes compared with that in uninfected lymphocytes. In gammadelta T lymphocytes, expression of IFN-gamma, not IL-2, was increased in MV-infected cells compared with that in uninfected cells. IL-2 was increased mainly in MV-infected CD4+ lymphocytes and alphabeta T lymphocytes, whereas IFN-gamma was increased mainly in MV-infected CD8+ lymphocytes and gammadelta T lymphocytes. Expression of IL-4 was unaffected by MV infection. These results demonstrate that MV enhances intracellular levels of type 1 cytokines during the acute phase of measles.

Animals↗

PubMed1997

Reduced resuscitation fluid volume for second-degree experimental burns with delayed initiation of vitamin C therapy (beginning 6 h after injury).

We studied the hemodynamic effects of delayed initiation (6 h postburn) of antioxidant therapy with high-dose vitamin C in second-degree thermal injuries. Seventy percent body surface area burns were produced by subxiphoid immersion of 12 guinea pigs into 100 degrees C water for 3 s. The animals were resuscitated with Ringer's lactate solution (R/L) according to the Parkland formula (4 ml/kg/% burn during the first 24 h) from 6 h postburn, after which the resuscitation fluid volume was reduced to 25% of the Parkland formula volume. Animals were divided into two groups. The vitamin C group (n = 6) received R/L to which vitamin C (340 mg/kg/24 h) was added after 6 h postburn. The control group (n = 6) received R/L only. Both groups received identical resuscitation volumes. Heart rates, mean arterial blood pressure, cardiac output, hematocrit level, and water content of burned and unburned tissue were measured before injury and at intervals thereafter. No animals died. There were no significant differences in heart rates or blood pressures between the two groups throughout the 24-h study period. The vitamin C group showed significantly (P < 0.05) lower hematocrits 8 and 24 h postburn, and higher cardiac outputs after 7 h postburn. At 24 h postburn, the burned skin in the vitamin C group had a significantly (P < 0.05) lower water content (73.1 +/- 1.1) than that of the control group (76.0 +/- 0.8). In conclusion, delayed initiation of high-dose vitamin C therapy beginning 6 h postburn with 25% of the Parkland formula volume significantly reduced edema formation in burned tissue, while maintaining stable hemodynamics.

Animals↗

PubMed1997

Expression of platelet-derived growth factor and its receptor in livers of patients with chronic liver disease.

To find if platelet-derived growth factor contributes to liver fibrosis in chronic liver disease, we studied the expression of the B-chain of this cytokine and its beta-receptor in livers of patients with chronic hepatitis or cirrhosis. Seventeen patients were included in this study. Five specimens of liver tissue obtained during autopsy from subjects without liver disease were used as controls. The location of the peptides was identified by an immunohistochemical technique with monoclonal antibodies. Expression of mRNA for the B-chain was assessed by in situ hybridization. Cells stained for the B-chain and expressing its mRNA were identified as macrophages. In control tissues, only a few cells were stained. In the patients' specimens, most stained cells were in portal areas and their number increased with histologic liver damage. In intralobular areas, the stained cells were seen in regions of focal necrosis. Portal mesenchymal and perisinusoidal cells expressed beta-receptor. These cells were dense in periportal areas, where many myofibroblast-like cells were seen. These findings suggest that the B-chain of platelet-derived growth factor is released mainly by macrophages involved in inflammatory reactions. This cytokine probably acts on myofibroblast-like mesenchymal cells, and may be implicated in liver fibrosis in chronic liver disease.

Aged↗

PubMed1997

Inhibition of interleukin-2 receptor (CD25) expression induced on T cells from children with acute lymphoblastic leukemia.

Peripheral blood lymphocytes obtained from children with acute lymphoblastic leukemia (ALL) at onset were studied for the expression of interleukin-2 (IL-2) receptor alpha-chain (CD25) by two-color flow-cytometric analysis. Stimulated with anti-CD3 monoclonal antibody (mAb) alone. CD25 expression was significantly suppressed in CD4+ T cells from 27 of 48 (56.3%) cases and in CD8+ T cells from 29 of 48 (60.4%) cases. When stimulated with anti-CD3 mAb plus phorbol 12-myristate 13-acetate (PMA), CD25 expression was clearly restored in certain cases of ALL. When PMA plus ionomycin were used for stimulation of T cells. CD25 was inducible in a majority of cases. Interestingly CD25 expression upon anti-CD3 mAb stimulation was recovered after complete remission had been achieved. These observations suggest the presence in ALL children at onset of an in vitro defect in the signal transduction pathway of the T-cell-receptor/CD3 complex, resulting in inefficient CD25 expression. However, immune-staining analysis indicated that protein kinase C was normally translocated from the cytosol fraction to the cell membrane fraction. The mobilization of cytoplasmic free calcium is also normal.

Antibodies, Monoclonal↗

PubMed1997

Human immunodeficiency virus type-1 envelope glycoprotein gp120 induces expression of fusion regulatory protein (FRP)-1/CD98 on CD4+ T cells: a possible regulatory mechanism of HIV-induced syncytium formation.

Syncytium formation is one of major cytopathic effects of human immunodeficiency virus (HIV) infection, and requires the interaction of CD4 molecules on uninfected cells with HIV envelope glycoprotein gp120 expressed on HIV-infected cells. Recent evidence suggests chemokine receptors function as fusion cofactors. We have recently found that fusion regulatory protein (FRP)-1/ CD98 is involved in syncytium formation of HIV gp160-expressing U2ME-7 cells and TALL-1 cells persistently infected with HIV. However, resting lymphocytes were found to express no FRP-1 molecule. In this study, we demonstrated that recombinant gp120 (rpg120) has the ability to induce expression of FRP-1 on peripheral blood mononuclear cells (PBMC). Three-color flow cytometric analysis showed that rgp120-induced FRP-1 was expressed selectively on CD4+ T cells in a dose-dependent manner. FRP-1 expression level was maximum 3 days after addition of rgp120. Anti-CD4 and anti-gp120 antibodies blocked rgp120-induced FRP-1 expression. Co-cultivation of PBMC with HIV-1 gp160-expressing HeLa cells also resulted in the increased expression of FRP-1 on T cells. These results suggest that FRP-1 molecules are induced on CD4+ T cells via CD4-gp120 interaction and may play an important role in regulation of HIV-induced syncytium formation.

Antigens, CD↗

PubMed1997

Protein tyrosine kinase activation provides an early and obligatory signal in anti-FRP-1/CD98/4F2 monoclonal antibody induced cell fusion mediated by HIV gp160.

The mechanism by which anti-fusion regulatory protein-1 (FRP-1) monoclonal antibody (mAb) induced cell fusion was investigated using U2ME-7 cells that are CD4+U937 cells transfected with the HIV gp160 gene. Protein kinase inhibitors (H-7, H-89, herbimycin A and genistein) suppressed cell fusion of Cd+U2ME-7 cells induced by anti-FRP-1 mAb. H-7 and H-89 also inhibited the cell aggregation, but herbimycin A and genistein did not. Intriguingly, only when herbimycin A was added either before or simultaneously with addition of anti-FRP-1 mAb, was cell fusion suppressed, suggesting that tyrosine kinase is related with the initial step of polykaryocyte formation. Anti-FRP-1 mAb induced the rapid tyrosine phosphorylation of multiple cellular proteins. These effects occurred within 1 min and returned to near baseline by 60 min. The rapid tyrosine phosphorylation was suppressed by herbimycin A and genistein. Although it remains to be determined which protein tyrosine kinase(s) is involved in this response, pp130 tyrosine phosphorylation appears to be a specific and early signal transmitted after the interaction of FRP-1 with a specific antibody. pp130 was present in the cytosol fraction and was distinct from pp125FAK, p130CAS, vinculin, and beta 1-integrin. Thus, our study may present evidence for a novel pathway of protein tyrosine kinases that phosphorylate specific, still unknown protein substrates during polykaryocyte formation.

Antibodies, Monoclonal↗

PubMed1997

Selective motor neuron death and heat shock protein induction after spinal cord ischemia in rabbits.

Paraplegia is a serious complication that sometimes results from operation on the thoracic aorta. The mechanism of spinal cord injury has been thought to involve tissue ischemia, and spinal motor neurons are suggested to be vulnerable to ischemia. The exact mechanism, however, is not fully understood. To evaluate the mechanism of such vulnerability of motor neurons, we attempted to make a reproducible model for spinal cord ischemia and statistically analyzed cell damage. With this model, induction of heat shock protein 70 (HSP70) and heat shock cognate protein (HSC70) messenger ribonucleic acid molecules were investigated with Northern blot analysis for up to 7 days of reperfusion after 5 or 15 minutes of ischemia. Immunohistochemical studies of their proteins were also done. (heat shock proteins are a set of markers of neuronal injury after ischemia.) After 5 minutes of ischemia, there was no induction of HSP70 and HSC70 messenger ribonucleic acid molecules or their proteins, and all cells remained intact. In contrast, after 15 minutes of ischemia, HSP70 messenger ribonucleic acid was induced at 8 hours of reperfusion, and HSC70 messenger ribonucleic acid was expressed continuously at the control level. Immunoreactivity of HSP70 protein was slightly induced at 8 hours of reperfusion selectively in motor neurons, and about 70% of motor neuron cells showed selective cell death after 7 days of reperfusion. This study demonstrated induction of HSP70 messenger ribonucleic acid and its protein in motor neuron cells after transient ischemia in the spinal cord. This phenomenon was not accompanied by HSC70 induction.

Animals↗

PubMed1997

Salvage therapy for relapsed or refractory childhood acute lymphocytic leukemia by alternative administration a lymphoid- and myeloid-directed chemotherapeutic regimen consisting of dual modulation of ara-C, hydroxyurea, and etoposide.

Risk-directed chemotherapeutic regimens in recent use have improved the prognosis of children with acute lymphocytic leukemia (ALL). However, many patients relapse during or shortly after cessation of the initial continuation chemotherapy. Since achievement of a second complete remission (CR) is the initial step in successful retreatment effort, it is important to develop salvage protocols for children with relapsed or refractory ALL. In the present study, we developed a new salvage protocol (MLL-93) and applied the concept of dual chemical modulation of cytarabine, hydroxyurea, and etoposide with the alternative administration of high doses of myeloid- and lymphoid-directed agents. We also planned to perform allogeneic bone marrow transplantation (BMT) following a CR if patients had HLA-identical donor(s). The six patients treated with the MLL-93 protocol achieved a second CR. One patients in CR died of interstitial pneumonia after an unrelated allogeneic BMT. The other five patients have been in CR for 12-41 months. We suggest that the concepts of alternative administration of lymphoid- and myeloid-directed drugs and biochemical modulation are useful in the treatment of children with relapsed or refractory ALL.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Treatment of multidrug-resistant murine leukemia with antisense mdr1 oligodeoxynucleotides.

To overcome multidrug resistance in a P-glycoprotein-overexpressing P388/ADR murine leukemia cell line, antisense mdr1 phosphorothioate-oligodeoxynucleotide (AS-oligomer) was constructed. AS-oligomer inhibited P-glycoprotein expression and mdr1 mRNA in vitro in a dose-dependent manner, whereas sense mdr1 oligomer (SE-oligomer) had no effect at the doses used. When P388/ADR was treated in vitro with AS-oligomer and doxorubicin (ADR), ADR-resistance was reduced by approximately 2 logs. Furthermore, a single injection of AS-oligomer plus ADR intraperitoneally into B6D2F1 mice with P388/ADR significantly prolonged mean survival time in a dose-dependent fashion. Again, sense mdr1 oligomer had no effect in vivo. No side effects, either acute or chronic, were found with this treatment during the observation period. These results show that antisense mdr1 oligomer could be a useful tool to overcome multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1997

Primary non-Hodgkin's lymphoma of the larynx.

Three cases of primary non-Hodgkin's lymphoma of the larynx are described. Histologically, two tumours belonged to the category of low grade B-cell lymphomas of the small cell type (extranodal marginal zone B-cell lymphoma and lymphoplasmacytoid lymphoma), and the third was classified as a peripheral T-cell lymphoma of unspecified type. The clinical stage was IE in two cases, and IV in another case. In two cases, complete remission was obtained with radical radiotherapy. But in the other case, which was histologically lymphoplasmacytoid lymphoma, the response to radiotherapy was poor, and surgery was required. There was no relapse subsequent to treatment. Primary non-Hodgkin's lymphoma of the larynx is rare. Several reported cases have clinical features similar to those of MALT-type lymphomas arising in other extranodal sites. Although most of the reported cases have been cured with radiotherapy, in some cases dissemination to other extranodal sites may occur. Therefore careful periodic evaluation is imperative.

Adult↗

PubMed1997

Successful hematopoietic reconstitution by transplantation of umbilical cord blood cells in a transfusion-dependent child with Diamond-Blackfan anemia.

A 4-year-old boy with Diamond-Blackfan anemia and a history of multiple transfusions underwent umbilical cord blood transplantation from his HLA-identical female sibling born by vaginal delivery at 38 weeks. The patient was prepared with busulfan, cyclophosphamide and antilymphocyte globulin. Methotrexate and cyclosporin A were given for the prophylaxis of GVHD. Regimen-related toxicity was not observed and successful engraftment occurred, including the erythroid series. No evidence of acute or chronic GVHD has been observed for 14 months after transplantation. This is the first case of successful umbilical cord blood transplantation to a patient with Diamond-Blackfan anemia.

Blood Transfusion↗

PubMed1997

Conditioning with cyclophosphamide/antithymocyte globulin for allogeneic bone marrow transplantation from HLA-matched siblings in children with severe aplastic anemia.

Graft rejection has been a problem after bone marrow transplantation for patients with severe aplastic anemia (SAA). Ten children with SAA were conditioned for bone marrow transplantation from HLA-identical siblings, using cyclophosphamide (CY, 50 mg/kg) plus antithymocyte globulin (ATG, 15 mg/kg) for 4 successive days. Marrow was infused 36 h after the last dose of CY. Cyclosporin A and methotrexate were administered as graft-versus-host disease (GVHD) prophylaxis. All patients achieved durable engraftment at follow-up of 7-41+ months (mean, 25) without significant GVHD. Since investigators have used different sources, doses, and time schedules of ATG, we compared our results with other published reports. We conclude that CY/ATG conditioning is well tolerated and effective in children with SAA.

Adolescent↗

PubMed1997

Two cytotoxic pathways of natural killer cells in human cord blood: implications in cord blood transplantation.

Using K562 cells as a target we investigated cord blood (CB)-natural killer (NK) cytolytic pathways. The cytotoxicity of fresh CB-NK cells was significantly lower than that of peripheral blood mononuclear cells (PB MNCs). When CB was incubated with IL-2, the level of CB-NK cytotoxicity was increased and boosted to the level observed in PB-NK cells. Fresh CB-NK cells induced apoptosis in target cells. Activated CB cells induced apoptosis and necrosis in target cells, at the same level as PB MNCs. CB stem cell transplantation may also induce graft-versus-host disease (GVHD)/graft-versus-leukaemia (GVL), similar to bone marrow transplantation.

Apoptosis↗