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Biomedical subjects

M Yazaki

Publications and source records attributed to M Yazaki.

At least 37 records · Page 2Linked to original sources

Murine Delta homologue, mDelta1, expressed on feeder cells controls cellular differentiation.

The Delta/Serrate-Notch pathway is involved in intercellular signaling that controls cell fate during the development of invertebrates and vertebrates. Delta is a prototype of Notch ligands and has been studied extensively in Drosophila. In higher vertebrates, four Delta/Serrate homologues and four Notch homologues have been identified. Recent studies showed that the murine Delta homologue, mDelta1, is essential in early embryogenesis. The biological activity of mammalian Delta and its roles in cellular differentiation, however, have remained unclear. In this study, we first surveyed expression of mDelta1 in the adult mouse and found it to be present in a wide range of tissues. For testing biological activity of mDelta1, we expressed a mDelta1 full-length cDNA in L cells using a eukaryotic expression vector. Effects of mDelta1 on cellular differentiation were examined in two independent systems, featuring C2C12 myogenic differentiation and multipotent murine bone marrow cell differentiation. Inhibition of the former was observed with mDelta1 expression on L cells, associated with suppression of myogenin, a myogenic transcription factor. Expression of mDelta1 in conjunction with GM-CSF promoted differentiation of bone marrow cells to myeloid dendritic cells at the expense of other lineages. Although the effects of mDelta1 on two differentiation systems appeared opposing, as inhibition occurring in one and induction in the other, this can be understood by the unifying concept of generation of diverse cell types from equivalent progenitors. Thus, the present study provided evidence that mammalian Delta participates in intercellular signaling, determining the cell fate in a wide variety of tissues.

Animals↗

A novel minor histocompatibility antigen recognized by HLA-A31 restricted cytotoxic T lymphocytes generated from HLA-identical bone marrow donor lymphocytes.

Bulk cytotoxic T lymphocytes (CTL) were generated by in vitro stimulation of BMT donor lymphocytes with Philadelphia chromosome (Ph)-positive leukemic cells from an HLA-identical sibling patient. CTL were cytotoxic against the patient's leukemic cells as well as the EBV-lymphoblastoid cell line (EBV-LCL) generated from the patient's cells, suggesting that they recognize a minor histocompatibility antigen (mHAg). Subsequently, several CTL lines were established by a limiting dilution method and analyzed. One of these CTL lines, 16C12 CTL which used a single TCRbetaV3S1 for CD8 cells, lysed HLA-A31-positive leukemic cells and EBV-LCL, but not fibroblasts. The cytotoxicity against the patient's leukemic cells and EBV-LCL was blocked by anti-HLA-A31 moAb, anti-HLA-class I moAb, and anti-CD8 moAb, suggesting that this mHAg was presented with HLA-A31. The antigen recognized by 16C12 CTL seemed to be a novel mHAg, since HLA-A31 restricted antigen has not been reported to date and 16C12 CTL showed no cytotoxicity against EBV-LCL which probably express known mHAgs. CTL detecting this mHAg may play an important role in the GVL effect in HLA-A31-positive BMT patients.

Bone Marrow Transplantation↗

Demography of sleep disturbances associated with circadian rhythm disorders in Japan.

To clarify the demography of delayed sleep phase syndrome (DSPS), non-24-h sleep-wake syndrome, and irregular sleep-wake pattern in Japan, a cross-sectional nationwide epidemiological survey was conducted. 1525 adults (age: 15-59 years) were randomly sampled from telephone directories, and they received screening questions over the phone. Persons who were suspected of having the disorders were requested to fill out the second questionnaire, and asked to keep a sleep log for 4 weeks. Diagnoses were made according to the International Classification of Sleep Disorders criteria. As a result, the prevalence of DSPS was estimated to be 0.13%.

Adolescent↗

Clinical characteristics of aged Becker muscular dystrophy patients with onset after 30 years.

To elucidate the clinical characteristics of aged patients with Becker muscular dystrophy (BMD), 4 patients with this disease who were over 50 years were examined. The ages at onset in all patients were later than 30 years. All were proven to have a deletion around exons 45-55 of the Duchenne muscular dystrophy (DMD) gene. Two patients became wheelchair bound in their 40s or beyond, while the other 2 (aged 73 and 69, respectively) were still able to walk at the time of examination. Three of 4 patients had no obvious hypertrophy in their calves, which is known to be one of the characteristic clinical features in the juvenile BMD patients. Serum creatine kinase levels were elevated in all patients, but not markedly (mean 444.8 +/- 230.3 U/l; normal value < 180 U/l). Dilated cardiomyopathy was clinically apparent in 2 patients. We emphasize that some BMD patients are free of muscular symptoms until their 50s and are still self-supporting in their 60s or 70s.

Age of Onset↗

Biological characteristics and prognostic value of in vitro three-drug resistance to prednisolone, L-asparaginase, and vincristine in childhood acute lymphoblastic leukemia.

The purpose of this study was to investigate the biological characteristics and prognostic value of in vitro three-drug resistance to prednisolone, L-asparaginase, and vincristine in childhood acute lymphoblastic leukemia (ALL). We carried out in vitro tests with a 4-day culture and a methyl-thiazol-tetrazolium assay on bone marrow samples from 209 children newly diagnosed with ALL. After testing the resistance of leukemic cells to 14 drugs, we classified the patients into two groups according to their sensitivity to three drugs (prednisolone, L-asparaginase, and vincristine) used in remission induction therapy. The three-drug resistant group (RR: sensitive to no drugs or to one drug) correlated with both short-term and long-term treatment failure. Three-year event-free survival (95% confidence interval) for the sensitive group (SS: sensitive to two or three drugs) was 0.813 (0.773-0.853) and that of the RR group was 0.616 (0.569-0.669) (P = 0.0001). Univariate analysis showed that Philadelphia-chromosome (Ph1) positivity and immunophenotype of mixed lineage were also prognostic factors in the 209 patients. The prognosis of the SS/RR drug resistance profile within 14 Ph1 patients was marginally significant (P = 0.062). Multivariate Cox regression analysis showed that Ph1 was an overwhelmingly adverse factor in event-free survival, with a relative hazard of 5.37 (2.57-11.21, P < 0.0001), followed by RR, with a relative hazard of 2.98 (1.69-5.25, P = 0.0001). Furthermore, we clarified the characteristics of the RR group by examination of the pattern of drug resistance to other drugs in comparison with the SS group. The leukemic cells of RR patients were more resistant than those of SS patients (P < 0.0001) to all the drugs tested, with resistance ratios of 1.6 to 13.1 (mean 3.4). In conclusion, in vitro three-drug resistance at the initial stage is an important independent predictor of treatment failure for both induction response and long-term outcome in childhood ALL.

Adolescent↗

Detection of bcr/abl fusion transcripts by semiquantitative multiplex RT-PCR combined with a colormetric assay in Ph positive leukemia.

We studied the feasibility of the clinical application of a new bcr/abl analysis system, C-TRAK t(9;22), consisting of a multiplex RT-PCR and a colormetric assay. With this system, bcr/abl transcripts could be detected in all of 24 cytogenetic Philadelphia chromosome (Ph) positive leukemia patients and in none of eight Ph negative patients. Multiple bcr/abl transcripts could be detected in three of the 24 Ph positive patients, the fusion of bcr exon 1 to abl exon 2 (e1a2 junction) dominated that of bcr exon 13 to abl exon 2 (b2a2 junction) in two cases and that of bcr exon 14 to abl exon 2 (b3a2 junction) and b2a2 dominated e1a2 in one case. This system was sensitive enough to be able to detect even one bcr/abl transcript-producing cell in 50000 bcr/abl negative background cells, thus making it suitable for semiquantitative evaluation. Minimal residual disease (MRD) was monitored in one Ph positive leukemia patient who underwent allogenic bone marrow transplantation (allo-BMT). After allo-BMT, a weak positivity of the bcr/abl transcript continued with no clinical relapse; this result was consistent with that of a conventional nested PCR assay using ethidium bromide staining. Including all the procedures for RNA extraction, it took only about 10 h to detect the bcr/abl transcripts. Our findings indicate that this bcr/abl analysis system provides a quick and sensitive method for screening bcr/abl transcripts and possibly for monitoring MRD in Ph positive leukemia patients.

Acute Disease↗

A novel splicing mutation in the ceruloplasmin gene responsible for hereditary ceruloplasmin deficiency with hemosiderosis.

Hereditary ceruloplasmin deficiency with hemosiderosis (aceruloplasminemia) is a newly recognized autosomal recessive disorder of copper-iron metabolism due to mutations in the ceruloplasmin (Cp) gene. We report here a novel mutation in the Cp gene in a 54-year-old Japanese woman with this disease. She showed clinical triad; diabetes mellitus, retinal degeneration and neurological disorder in her middle age. Laboratory findings were characteristic for no detectable serum ceruloplasmin and increased serum ferritin. Liver biopsy revealed excessive storage of iron in hepatocytes and magnetic resonance imaging of the brain was indicative of increased iron content in the basal ganglia, thalamus and dentate nucleus. The a-->g substitution at the splice acceptor site of the intron 6 (1209-2) caused a 8-bp deletion in Cp mRNA by defective splicing, resulting in a premature termination codon at the amino acid position 388. Truncation of Cp, even if effectively translated, may cause loss of its normal function because of drastic change in its triangular structure.

Alternative Splicing↗

Insertional mutation by transposable element, L1, in the DMD gene results in X-linked dilated cardiomyopathy.

X-linked dilated cardiomyopathy (XLDCM) is a clinical phenotype of dystrophinopathy which is characterized by preferential myocardial involvement without any overt clinical signs of skeletal myopathy. To date, several mutations in the Duchenne muscular dystrophy gene, DMD , have been identified in patients with XLDCM, but a pathogenic correlation of these cardiospecific mutations in DMD with the XLDCM phenotype has remained to be elucidated. We report here the identification of a unique de novo L1 insertion in the muscle exon 1 in DMD in three XLDCM patients from two unrelated Japanese families. The insertion was a 5'-truncated form of human L1 inversely integrated in the 5'-untranslated region in the muscle exon 1, which affected the transcription or the stability of the muscle form of dystrophin transcripts but not that of the brain or Purkinje cell form, probably due to its unique site of integration. We speculate that this insertion of an L1 sequence in DMD is responsible for some of the population of Japanese patients with XLDCM.

5' Untranslated Regions↗

[Efficacy of granisetron, a 5-HT3 antagonist, in the prevention of nausea and vomiting induced by conditioning for hematopoietic stem cell transplantation].

One hundred and eleven patients receiving conditioning regimens for hematopoietic stem cell transplantation (HSCT) were administered a single intravenous dose (40 micrograms/kg) of granisetron before chemo-radio therapy. The efficacy of the drug was assessed every 24 hours, rating the control of nausea and vomiting as complete, major, minor or failure. On day 1, 23 of 48 patients (47.9%) who received cyclophosphamide (60 mg/kg/day), achieved control of emesis with complete or major response. On day 2, 17 of 47 patients (36.2%) achieved control emesis. During total body irradiation (TBI) (10 approximately 12 Gy/2 approximately 3 days), 21 of 33 patients (63.6%) achieved control of emesis on day 1 and 22 of 32 patients (68.6%) achieved control of emesis on day 2. During melphalan administration (60 approximately 100 mg/m2/day), 20 of 28 patients (71.4%) achieved control of emesis on day 1. Adverse effects were observed in seven patients but were not serious. We concluded that granisetron has a major role in preparation for HSCT.

Adolescent↗

Successful prevention of hematological relapse for a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia after allogeneic bone marrow transplantation by donor leukocyte infusion.

Donor leukocyte infusion (DLI) was carried out on a 12-year-old girl with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) who received allogeneic bone marrow transplantation from an HLA-identical sibling. This is the first report of DLI use before the onset of hematological relapse monitored by the results of RT-PCR. This patient has been in CR for 11 months after BMT, suggesting this alternative treatment is promising for Ph+ ALL with positive reverse transcriptase-polymerase chain reaction (RT-PCR) following BMT.

Bone Marrow Transplantation↗

[Correlation of cardiac muscle involvement and the dystrophin gene abnormality in Becker muscular dystrophy].

Cardiomyopathy is one of the most important clinical manifestations in Becker muscular dystrophy (BMD), but the severity of cardiac involvement is not usually related to that of skeletal muscle disability in this disease. In general, BMD patients who carry the mutations in the 5' end of the dystrophin gene tend to show severe cardiac dysfunction compared with skeletal myopathy, and these mutations may be responsible for more selective involvement of dystrophin appearance in the myocardium. In this article, we review the causative relationship of the variable clinical pictures and the dystrophin gene abnormalities in BMD patients, focusing on the severity of cardiac disorder.

Cardiomyopathy, Dilated↗

Mutation of potential N-linked glycosylation sites in the Alzheimer's disease amyloid precursor protein (APP).

In order to study the mechanism of intracellular sorting and processing of the Alzheimer's disease amyloid precursor protein (APP), we deleted two potential N-linked glycosylation sites of APP by site-directed mutagenesis. Substitution of alanines for the critical asparagine residues Asn467 and Asn496 was performed. Wild-type and mutant APPs were expressed in COS-1 cells by cDNA transfection and the expressed of the protein and secretion of N-terminal large fragment was observed. The initial secretion of the mutant APP appeared to be slow compared with wild-type. In addition, we found that a distinct APP fragment, the cytosolic form, is transiently increased in the cytosol fraction of COS-1 cells. These results suggest that aberrant processing occurs following the expression of a mutant APP with Ala substituted for Asn, and that glycosylation may modulate the intracellular sorting of APP.

Alzheimer Disease↗

Complete neurological recovery of an adult patient with type II citrullinemia after living related partial liver transplantation.

Type II citrullinemia is an adult-onset hepatocerebral disease caused by a deficiency of argininosuccinate synthetase in liver. A 25-year-old Japanese man suddenly developed encephalopathy, showing disorientation and flapping tremor. Plasma concentrations of ammonia and citrulline were extremely high, and hepatic argininosuccinate synthetase activity was deficient. The patient's condition deteriorated rapidly in spite of intensive medications. Therefore, we performed a partial liver transplantation using a graft obtained from his healthy 61-year-old father. After surgery, his neurological symptoms soon disappeared and plasma levels of ammonia and citrulline were normalized within 3 months after operation. Type II citrullinemia is one fulminant form of various liver-based metabolic diseases, and immediate liver transplantation is necessary to rescue patients with this disease. As liver transplantation from cadaveric donor is still not possible in Japan, it seems justifiable to use living related partial liver transplantation for our patient.

Adult↗

Analysis of 55 transplantations from unrelated volunteer donors facilitated by Tokai Marrow Donor Bank.

In October, 1989, the Tokai Marrow Donor Bank (TMDB) was established through the cooperation of patients' families, the branches of blood centers of Japanese Red Cross and the hematologists' group in Tokai Area (Aichi, Shizuoka, Gifu and Mie Prefectùres) in Japan to facilitate the procurement of suitable marrow from unrelated volunteer donors for patients lacking related donors. The number of human leukocyte antigen (HLA)-A, B typed donors totaled 3,083 and the number of patients registered for donor search totaled 1,415 by June 1992, when the activities of TMDB were transferred to the newly created Japan Marrow Donor Program (JMDP), and 55 transplanations from unrelated donors facilitated by TMDD were performed.

Adolescent↗

Detection of donor lymphocytes in the cerebrospinal fluid of a patient with metachromatic leukodystrophy following bone marrow transplantation.

An unrelated donor bone marrow transplant (UD-BMT) was carried out on a 10-year-old patient with metachromatic leukodystrophy (MLD). We collected cerebrospinal fluid (CSF) on day +168 and cultured it with recombinant IL-2 and PHA-P to examine the origin of cells in the CSF. Analysis on variable number of tandem repeat (VNTR) of lymphocytes in the CSF amplified by PCR revealed that lymphocytes in the CSF were of donor origin. These data support that BMT at an early stage may prevent deterioration in MLD. Although the patient developed grade III acute GVHD with rash and diarrhea, we successfully treated acute GVHD using rabbit anti-human thymocyte immunoglobulin (ATG). UD-BMT may be an alternative treatment for patients with MLD in the absence of an HLA matched family donor.

Bone Marrow Transplantation↗

[Familial amyloid polyneuropathy type IV (Finnish type)--a clinicopathological study].

Familial amyloid polyneuropathy type IV (Finnish type, FAP IV) is one form of hereditary generalized amyloidosis with autosomal dominant trait and is characterized clinically by a triad of corneal lattice dystrophy, caudal cranial neuropathy and various skin changes. The vast majority of the families with this disorder originated from Finland. We carried out a clinicopathological study of a large FAP IV kindred recently found in Japan. This family consisted of 73 members in 5 generations with 17 affected individuals and 7 of them (ages 45 to 73) were examined in detail. All patients showed typical clinical manifestations, lacking significant peripheral neuropathy in the limbs. However, autonomic dysfunctions including orthostatic fainting and dysuria were seen in 2 patients. Congophilic amyloid deposits were commonly observed in an aspiration biopsy of abdominal fat tissues, and noradrenergic nerve fibers of the rectal mucosa were reduced in one patient with autonomic symptoms. DNA analysis using PCR revealed a single base change (G to A) at nucleotide position 654 of the gelsolin gene in 7 patients and one asymptomatic individual. The clinical pictures and gene abnormality in this Japanese family are very similar to those reported in Finland. Moreover, this study added that autonomic nerves might be involved in FAP IV patients at the advanced stage.

Adipose Tissue↗