Biomedical subjects

Hiromi Seo

Publications and source records attributed to Hiromi Seo.

9 recordsLinked to original sources

PubMed2005

Methylation analysis of the adenomatous polyposis coli (APC) gene in adult T-cell leukemia/lymphoma.

We investigated methylation status of the adenomatous polyposis coli (APC) gene in adult T-cell leukemia/lymphoma (ATL). APC methylation was found in 15 of 31 (48%) primary samples, and 2 of 4 (50%) ATL cell lines. Methylation of the APC gene occurred more frequently in acute ATL (12/21) (57%) than chronic ATL (1/8) (13%) (P = 0.03). APC was not expressed in the APC-methylated ATL cell line ST1. Demethylation with 5-azacytidine treatment restored APC expression in the ST1 cell line. Our data show that hypermethylation of the APC gene is involved in the pathogenesis of ATL.

Adenomatous Polyposis Coli Protein↗

PubMed2005

Methylation of the MLH1 gene in hematological malignancies.

Hypermethylation of the MLH1 gene has been described in many kinds of human cancers with microsatellite instability (MSI). However, it is not clear whether the same mechanism occurs in hematological malignancies. Genomic DNA was extracted from 31 patients with adult T-cell leukemia/lymphoma (ATL), 9 patients with acute lymphoblastic leukemia (ALL) who had MSI, and 12 leukemia and lymphoma cell lines with MSI. Aberrant methylation of the MLH1 gene was found in 2/31 (6%) ATL patients, and in 1/12 (8%) cell lines with MSI. MLH1 promoter was not methylated in either of the twelve peripheral blood samples from normal individuals or ALL samples. The MLH1 gene was expressed in the normal peripheral blood samples, but not in the MLH1-methylated cell line KCL22. Demethylation with 5-Azacytidine treatment restored MLH1 expression in the KCL22 cell line. Methylation of the MSH2 gene was not found in any of the samples. Our data show that hypermethylation of the MLH1 gene is occasionally involved in the pathogenesis of hematological malignancies, but is not always associated with MSI.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Allelic loss during progression of follicular lymphoma.

We performed loss of heterozygosity (LOH) analysis on matched lymph nodes before and after progression of follicular lymphoma (FL), and found novel LOH on chromosome arm 12p. This LOH has not been previously reported in association with FL transformation. Other sites of frequent LOH include chromosome arms 6q and 9p. LOH was observed in both transformed FL and relapse FL. These data suggest that altered tumor suppressor genes exist on 6q, 9p, and 12p that have an important role in the progression of FL. Genetic changes accumulated in relapsed FL in the absence of histological changes compared to initial diagnosis.

Chromosomes, Human, Pair 12↗

PubMed2004

Methylenetetrahydrofolate reductase genotype does not play a role in adult T-cell leukemia/lymphoma pathogenesis among human T-lymphotrophic virus type 1 carriers.

Human T-lymphotropic virus type 1 (HTLV-1) is associated with adult T-cell leukemia/lymphoma (ATL). However, the incidence of ATL is low among HTLV-1 carriers suggesting additional mechanisms are involved in the progression of the disease. A recent study found that polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene influence the susceptibility to malignant lymphoma. We have analyzed the MTHFR genotype in 81 HTLV-1 carriers and 87 ATL patients. No statistically significant associations were found between MTHFR genotype and development of ATL. These data suggest that genetic polymorphisms in the MTHFR locus do not play a role in ATL pathogenesis among HTLV-1 carriers.

Carrier State↗

PubMed2004

Aberrant methylation in promoter-associated CpG islands of multiple genes in relapsed childhood acute lymphoblastic leukemia.

Methylation profile was analyzed in nine cases of relapsed childhood acute lymphoblastic leukemia (ALL) for p14, p15, p16, Rb, MGMT, APC, hMLH1, RARbeta, RIZ, DAPK, and FHIT genes by using methylation specific polymerase chain reaction (MSP) analysis. Frequency of methylation in each gene was: MGMT, 56%; RARbeta, 44%; and p16, 22%, respectively. None of the p14, p15, Rb, APC, hMLH1, RIZ, DAPK, and FHIT genes were hypermethylated. Five (56%) of 9 cases showed methylation of at least one gene. All of the samples with hypermethylation in p16 and MGMT gene at relapse, had already acquired the change at the time of initial diagnosis. Interestingly, three of 4 cases with RARbeta gene methylation at relapse did not have methylation of this gene at the time of initial presentation. These results suggest that hypermethylation might be involved in the relapse of childhood ALL.

Adolescent↗

PubMed2004

Academic performance and comparative effectiveness of computer- and textbook-based self-instruction.

We intended to clarify the influence of student academic ability on the effectiveness of CAI, using data of a study to assess the effectiveness of a new type of CAI software, cyberPatient (CP), at Kochi Medical School (KMS). A total of 59 third-year students were randomly assigned to four groups: Group-1 used a textbook for self-instruction, Group-2 used CP, Group-3 used both types of learning materials, and Group-4 did not learn. Learning performance was evaluated by multiple-choice examination and OSCE. In order to clarify the influence of students' academic ability on the effectiveness of CAI, statistical analyses were conducted, assigning students as either high or medium or low performance students. High performance students from Group-1, -2 and -3 did not differ significantly in test performance after self-instruction. However, low performance students in Group-1 scored significantly lower than those in Group-2 and -3. All students in Group-2 and -3 reported that CP stimulated willingness to learn and assisted understanding. The present analysis suggested that effectiveness of CAI might be associated with the academic ability of students.

Computer-Assisted Instruction↗

PubMed2003

Allelotype analysis in relapsed childhood acute lymphoblastic leukemia.

We performed for the first time the allelotype of relapsed childhood acute lymphoblastic leukemia (ALL). A total of 38 cases were screened for loss of heterozygosity (LOH) using 71 markers. In all, 26 (68%) patients showed LOH on at least one chromosomal arm, indicating that LOH is a frequent event at relapse. The most frequent loss was found on chromosomal arm 9p at the p16/INK4a locus (39%). LOH at the TEL gene locus on chromosomal arm 12p also occurred often (25%). Frequent loss was observed on chromosome arms 4q (20%), 6q (21%), and 17q (20%). Sequential analysis (i.e. samples obtained from both initial diagnosis and relapse) shows that some patients (63%) have the identical LOH status at both phases, suggesting the presence of the same clone. Other samples (37%) showed distinct LOH alterations, indicating clonal evolution at relapse. Despite the heterogeneous and complex changes, some shared LOH loci occurred in these matched samples, suggesting that many of the same tumor-suppressor genes are aberrant at both phases. In summary, novel tumor-suppressor genes on chromosome arms 4q, 6q, and 17q, as well as the p16 and TEL genes, have an important role in the relapse of childhood ALL.

Adolescent↗

PubMed2003

Mutations in the retinoblastoma-related gene RB2/p130 in adult T-cell leukaemia/lymphoma.

The retinoblastoma (Rb) family consists of the tumor suppressor Rb/p105 and related proteins p107 and Rb2/p130. Although the involvement of the RB/p105 gene in Adult T-cell leukaemia/lymphoma (ATL) has been studied, no mutational data is reported regarding the RB2/p130 gene in ATL. We screened for mutations of the RB2/p130 gene. Mutation was detected in 1 of 41 primary ATL sample. This is the first report describing mutation of the RB2/p130 gene in ATL, suggesting that RB2/p130 may be involved in the development of ATL, and may behave as a tumor suppressor gene in T lymphocytes.

Cell Cycle↗

PubMedDate not supplied

Effect of age on chronological variation of acute myocardial infarction onset: study in Japan.

To evaluate the effect of age on circadian and seasonal variation in the onset of acute myocardial infarction (AMI) in Japan, we studied 725 patients whose onset date and time of the symptom were determined. In the analysis of all AMI patients, the occurrence showed significant circadian variation (P< 0.01); 30% of episodes occurred between 0600 and 1200h which formed a dominant morning peak. In the analysis of separate age-groups, a significant difference in the occurrence among four 6-hour periods of day was observed only in the early-elderly group (65-74 years), in which a significant (P < 0.01) morning peak comprising 33% of episodes was observed between 0600 and 1200 h. The monthly variation of AMI onset in total subjects tended to show two peaks; April and August. The seasonal variation tended to show a trough in autumn when analyzed in all patients, but the variation was significant only in middle-aged group (< 65 years). In conclusion, the incidence of AMI in Japanese population showed dominant morning peak, and tended to show autumn trough. These circadian and seasonal variations were affected by age.

Age Factors↗