[Automated systems for nucleic acid tests by polymerase chain reaction].
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Autoanalysis↗
Biomedical subjects
Hayato Miyachi
Publications and source records attributed to Hayato Miyachi.
[Genetic tests for molecular markers of cancer].
Based on recent advancements in biotechnology and molecular oncology, genetic tests for molecular markers have been widely used for diagnosis and therapeutic monitoring in patients with hematological malignancies. However, incorporation of such tests has been limited in the care of patients with non-hematopoietic malignancies. The reasons for this include difficulty in sampling of the tumor tissue, and a lack of evidence for cost-effectiveness in the test utilization. A practical approach is the use of bodily fluids, such as blood, sputum, urine and feces, as specimens for early detection and monitoring of tumor-derived nucleic acid sequences. The prospect has been raised for development of tests for individualized medicine based on genetic information such as prediction of responsiveness to chemotherapeutic agents for selection of treatment, which will be promoted by gene expression profiling using DNA microarray.
Biomarkers, Tumor↗
Smoldering myeloma associated with zonisamide treatment.
A 39-year-old man was found to have hyperproteinemia after being treated with zonisamide for 10 years. Laboratory examination revealed a serum M-protein which consisted of IgG (lambda) and an increased number of plasma cells in the bone marrow, resulting in a diagnosis of smoldering myeloma. Considering his age, zonisamide was suspected to play an etiologic role in the occurrence of smoldering myeloma. Zonisamide was changed to sodium valproate. Subsequently the M-protein did not increase over 13 months. When zonisamide is used, the monitoring of serum levels of M-protein and patterns of gammaglobulin is warranted.
Adult↗
Extensive wall thickening in intestinal Burkitt lymphoma.
OBJECTIVE: To evaluate intestinal lesions in Burkitt lymphoma. METHODS: Ultrasonography was used in the initial evaluation of 6 Japanese patients with intestinal Burkitt lymphoma. RESULTS: Ultrasonography revealed marked wall thickening of the colon from the cecum through either the ascending or the transverse colon, which led to a target sign (4 cases) or a pseudokidney sign (2 cases). The target sign histopathologically corresponded to invagination of an occult tumor of the cecum into the ascending colon. Wall thickening of the colon when associated with a target or pseudokidney sign corresponded to marked lymph edema or a diffuse infiltration of Burkitt lymphoma cells into the intramural layers, respectively CONCLUSIONS: Ultrasonography provides useful information in the initial evaluation of intestinal lesions with distinctive histopathologic characteristics in Burkitt lymphoma.
Adolescent↗
[cDNA microarray technology as a laboratory examination method: a gene expression profiling test for analysis of drug resistance in tumor cells].
cDNA microarray technology permits the simultaneous measurement of the expressions of thousands of genes. The technology is now an indispensable research tool in molecular biology, and the challenge is its development and usage as clinical diagnostic tools. cDNA microarray can be used to identify gene expression profiles in tumor cells which correlate strongly with the treatment responsiveness such as drug resistance and clinical outcome of the disease despite similar phenotypes. For the introduction of cDNA microarray into laboratory examination, many issues need to be resolved. Design of a diagnostic array must be developed with defined sequences based on interpretation of huge quantities of data from experimental arrays to predict treatment responsiveness. Assay quality must be improved in terms of detection sensitivity, reproducibility, and linear dynamic range for RNA quantitation. Generally available instruments, which are much less expensive and more practical, need to be developed. Along with the improvement of the assay as a laboratory examination method, cDNA microarray will facilitate the integration of diagnosis and therapeutics, and the introduction of individual medicines.
Clinical Laboratory Techniques↗
Reversal of drug resistance using hammerhead ribozymes against multidrug resistance-associated protein and multidrug resistance 1 gene.
We examined the effects of suppressing multidrug resistance-associated protein (MRP) and multidrug resistance 1 (MDR1) gene expression in HCT-8DDP human colon cancer cell lines, which showed both cisplatin and multidrug resistance. Hammerhead ribozymes, designed to cleave MRP mRNA (anti-MRP Rz) and MDR1 mRNA (anti-MDR1 Rz), were transfected into the HCT-8DDP cells. Drug sensitivity was estimated by MTT assay in vitro. The HCT-8DDP/anti-MRP Rz cells were more sensitive to doxorubicin (DOX) and etoposide (VP-16) by 2.5- and 4.1-fold, respectively, compared with HCT-8DDP cells. The HCT-8DDP/anti-MDR Rz cells were more sensitive to DOX and VP-16 by 2.3- and 3.8-fold, respectively. The anti-MRP Rz and anti-MDR1 Rz significantly down-regulated resistance to DOX and VP-16, while anti-MRP Rz and anti-MDR1 Rz did not affect resistance to cisplatin, methotrexate and 5-fluorouracil. The hammerhead ribozyme-mediated specific suppression of MRP or MDR1 was sufficient to reverse multidrug resistance in the human colon cancer cell line.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
[Recent advances in molecular diagnostic tests].
Recent advances in molecular biotechnologies have facilitated laboratory use of molecular diagnostic tests. Automated systems for amplification and detection, and lately for extraction, of nucleic acid sequences have been developed. The automated systems have allowed improvement of not only assay efficiency but also quality control of the tests. The information on the genome sequence from the human genome project has been studied to elucidate functions of genes and proteins and the clinical significance of nucleic acid sequences with post-genomics such as expression profiling using DNA microarray, proteomics, and single nucleotide polymorphism analysis, in conjunction with bioinformatics. Now the challenge is the development and application of these new technologies as clinical diagnostic tools. Design of a diagnostic array or panel must be developed with defined sequences based on interpretation of a huge quantity of experimental data to meet clinical demands. There is a need for development of generally available instruments that are inexpensive, practical and more importantly reproducible and reliable.
Computational Biology↗
Platelet activation in patients with chronic hepatitis C.
OBJECTIVE: To elucidate the mechanisms of thrombocytopenia in chronic hepatitis C (CHC), we investigated platelet activation in patients with chronic viral liver diseases. METHODS: Platelet activation was evaluated with flow cytometry in twenty-five patients with chronic viral hepatitis and 11 patients with liver cirrhosis of viral etiology. Liver biopsies were carried out in all patients. RESULTS: The platelet counts decreased significantly in patients with CHC and in patients with liver cirrhosis compared to controls, but not in patients with chronic hepatitis B (CHB). Patients with CHC had a significantly higher percentage of platelets positive for activation-dependent monoclonal antibodies (MoAbs), and also had a higher percentage of platelet microparticles (PMP), a marker of platelet activation, than patients with CHB. There was a significant correlation between the percentage of PMP and the levels of liver fibrosis markers, such as serum hyaluronate and N-terminal propeptide of type III procollagen (P-III-P), in CHC, suggesting the relationship between platelet activation and liver fibrosis. Platelet activation was markedly enhanced in CHC patients with high histological scores of liver fibrosis. CONCLUSION: Patients with CHC have increased platelet activation, which may contribute to the occurrence of thrombocytopenia in CHC. Liver fibrosis may play a role in activation of platelets in CHC.
Adult↗
Platelet activation in patients with obstructive sleep apnea syndrome and effects of nasal-continuous positive airway pressure.
OBJECTIVE: Our study was undertaken to determine whether increased platelet activation occurs in patients with obstructive sleep apnea syndrome (OSAS) and whether a therapy with nasal-continuous positive airway pressure (N-CPAP) alters this activation. METHODS: We measured the positive rate of activated platelets using activation-dependent monoclonal antibodies (MoAb) and flow cytometry in whole blood from 94 patients with OSAS, and from 31 age-matched controls. Thrombotic vascular diseases were surveyed as a background of alternative of platelet activation. RESULTS: The positive rate for activated platelets was significantly higher in patients with OSAS ( PAC1 52.6 +/- 22.9 %, CD62P 6.8 +/- 7.1%, mean +/- SD), as compared with healthy control subjects ( PAC1 16.7 +/- 8.6 %, CD62P 0.7 +/- 0.5 %, p < 0.001). The activation indexes were significantly reduced after 1 month with N-CPAP treatment as a whole (PAC1; from 52.6 +/- 22.9 to 44.2 +/- 22.4, p < 0.05, CD62P; from 6.8 +/- 7.1 to 5.3 +/- 5.5, p < 0.05). In nearly 60 % of patients, platelets activation remained high despite significant improvement of sleep apnea-episodes after N-CPAP. These patients had significantly higher incidence of previous myocardial infarction and/or cerebral infarction and abnormalities of head MRI and carotid sonograpy; indicating that the platelet activation appears to be induced by existing atheroma plaque and not by sympathetic activity in OSAS. CONCLUSION: In conclusion, patients with OSAS have increased percentages of activated platelets as assessed by flow cytometrical analysis of activation dependent surface markers, and were divided into two groups, one group with response to N-CPAP treatment in the reduction of platelet activation and the other without. One possible reason of no response to N-CPAP treatment in the reduction of platelet activation was suggested to be thrombotic diseases.
Adult↗
Methylthioadenosine phosphorylase as target for chemoselective treatment of T-cell acute lymphoblastic leukemic cells.
We analyzed the role of methylthioadenosine phosphorylase (MTAP) for chemoselective treatment of T-cell acute lymphoblastic leukemia (T-ALL). MTAP converts methylthioadenosine into adenine which serves as an alternative purine source, if de novo purine biosynthesis is inhibited by antimetabolites (i.e., methotrexate). The idea of the chemoselectivity concept is that tumors with MTAP deletion at chromosome 9p21 are more susceptible to antimetabolites than normal cells without such a deletion. First, we screened 13 T-ALL lines for 9p21 deletions by comparative genomic hybridization. Five cell lines revealed deletions at the short arm of chromosome 9, dim(9p21pter). Further analyses were performed with CEM cells in which the 9p21 deletion was corroborated by fluorescence in situ hybridization. CEM cells were transfected with an MTAP expression vector. A green fluorescent protein (GFP) plasmid was cotransfected, to monitor the transfection efficacy by flow cytometry. The response of MTAP-transfected cells to the antimetabolites methotrexate (MTX), trimetrexate (TMX), and L-alanosine (ALA) was decreased compared to mock control transfectants using growth inhibition assays. The activity of doxorubicin (DOX) which is not involved in DNA biosynthesis was not changed in MTAP transfectants. As the p16(INK4a) tumor suppressor gene resides also at 9p21, we transfected CEM cells with a p16(INK4a) expression vector. These transfectant cells were more resistant to all four drugs indicating that p16(INK4a) did not specifically affect antimetabolites. The chemoselective effect of antimetabolites in MTAP-deleted tumor cells may, however, be compensated by the development of drug resistance. To prove this possibility, we analyzed an MTX-resistant subline, CEM/MTX1500LV, in which the MTX-resistance conferring dihydrofolate reductase (DHFR) gene was amplified. While TMX exhibited considerable cross-resistance in CEM/MTX1500LV cells, ALA did not. Thus, ALA could exhibit chemoselectivity in 9p21/MTAP-deleted cells, even if DHFR amplification occurs. We conclude that ALA may be more suitable than MTX or TMX for MTAP-mediated chemoselective treatment of T-ALL. Pretherapeutical detection of 9p21 and MTAP deletion may be helpful in developing a predictive molecular chemosensitivity test for T-ALL.
Alanine↗
Genomic imbalances in drug-resistant T-cell acute lymphoblastic CEM leukemia cell lines.
Ten T-cell acute lymphoblastic (T-ALL) CEM cell lines selected for resistance toward methotrexate (CEM/MTX60PGA, CEM/MTX140LV, CEM/MTX1500LV, CEM/MTX5000PGA, CEM/MTXR1, CEM/MTXR2, and CEM/MTXR3), doxorubicin (CEM/ADR5000), vincristine (CEM/VCR1000), or hydroxyurea (CEM/HUR90), respectively, and parental drug-sensitive CCRF-CEM cells were analyzed using comparative genomic hybridization. Most genomic imbalances were not specific for drug resistance, as they were found in both parental and drug-resistant lines. Three aberrations were common to all or most cell lines analyzed: dim(5q35), dim(9p21p24), and enh(20q). We were concerned on those imbalances which were specifically present in drug-resistant but not in drug-sensitive cells. All methotrexate-resistant cell lines were characterized by an enhancement or an amplification of 5q13. The methotrexate resistance-conferring dihydrofolate reductase (DHFR) gene is located at this locus. Gain of DHFR was verified by PCR analyses. CEM/MTX60PGA, CEM/MTX140LV, CEM/MTX1500LV, and CEM/MTX5000PGA showed enh(14q21qter) and CEM/MTX5000PGA amp(5p13p15.2). These two loci harbor the methylenetetrahydrofolate dehydrogenase (MTHFD1) and 5'-methyltetrahdrofolate-homocysteine methyltransferase reductase (MTRR) genes, both of which are involved in folate metabolism. Their gain indicates a role in methotrexate resistance. A loss of 4q35 was found in CEM/MTXR2, CEM/MTXR3, and CEM/ADR5000 where the proapoptotic caspase-3 gene is located. The thioredoxin (TXN) locus 9q31 was enhanced in CEM/ADR5000 and CEM/MTX5000PGA cells. 2p22pter was increased in hydroxyurea-resistant CEM/HUR90 cells. Ribonucleotide reductase polypeptide M2 (RRM2), which confers resistance to hydroxyurea, resides at this locus. Other specific genomic imbalances in drug-resistant cell lines were dim(1p36.5), enh(4p), dim(8p22pter), enh(12p13), dim(17p), enh(18q12), enh(21q22.2), dim(21q22.2), and dim(22q13). All genomic imbalances were subjected to hierarchical cluster analysis and clustered image mapping to identify profiles of chromosomal aberrations in the cell lines. The obtained dendrograms allowed separation of imbalances common to all or most cell lines from other more individual aberrations. Furthermore, methotrexate-resistant cell lines clustered together. Our future efforts will be directed toward those imbalances which implicate still unknown candidate drug resistance genes.
Antineoplastic Agents↗