Biomedical subjects

T Kakihara

Publications and source records attributed to T Kakihara.

41 records · Page 3Linked to original sources

PubMedDate not supplied

Characterization of newly established human myeloid leukemia cell line (KF-19) and its drug resistant sublines.

A new human myeloid leukemia cell line, designated KF-19, and its drug resistant sublines have been established. The KF-19 cell line was established from the pericardial effusion of a patient with acute myeloid leukemia clinically resistant to chemotherapy and KF-19 cells were characterized by expression of myeloid markers and differentiation into neutrophil- and macrophage-like cells upon optimal stimulations. KF-19AraC, KF-19ADR and KF-19VCR were established as sublines resistant to cytosine arabinoside (AraC), adriamycin (ADR) and vincristine (VCR), respectively. Efflux of the corresponding drugs was documented in each cell line. Expression of the MDR1 gene and the P-glycoprotein was found only in KF-19ADR, which showed a cross resistance to anthracyclines and vinca alkaloids; this resistance was reversed by verapamil or cyclosporin A. KF-19VCR lacking MDR1 gene and P-glycoprotein expression showed only resistance to vinca alkaloids, which was partially reversed by verapamil and cyclosporin A. Unexpectedly, KF-19ADR and KF-19VCR displayed cross resistance to AraC, despite lack of alterations of deoxycytidine kinase (dCK) and deaminase (dA) activities. KF-19AraC showed an efflux of AraC as well as a decreased level of dCK, but not of dA. In addition, KF-19AraC showed cross resistance to VCR in the efflux assay. The cell lines reported herein will provide new aspects on the mechanisms of drug resistance in leukemic cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Reactivity of anti-AraC-resistant cell monoclonal antibody, YU-311, in formalin-fixed paraffin-embedded specimens of various hematopoietic disorders.

YU-311 is a monoclonal antibody reacting with cytosine arabinoside (AraC)-resistant human leukemic cell line and identifies a 92 kDa membrane protein. We have examined YU-311 reactivity with various hematopoietic disorders by an immunohistochemical method and evaluated a correlation between YU-311 expression and refractoriness to chemotherapy, retrospectively. YU-311 reacted with AraC-resistant human leukemia cell lines, in which a 92 kDa membrane protein was identified by Western blotting, whereas drug-resistant cell lines to other than AraC failed to express YU-311 antigen. The frequency of YU-311 positivity was significantly increased in relapsed cases. Only five cases were positive for YU-311 at diagnosis and 24 cases at relapse. Unexpectedly, only eight cases of relapsed leukemia/lymphoma expressed YU-311 and P-glycoprotein simultaneously. Most of the YU-311-positive relapsed cases showed clinical refractoriness for chemotherapy and then failed to induct complete remission or relapsed at short periods with short disease-free duration. These findings indicate that YU-311 expression is closely associated with some aspects of drug resistance, especially with AraC resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Photocatalytic activity of TiO2 particulate films prepared by depositing TiO2 particles with various sizes.

TiO2 particles of various sizes were prepared by grinding in cyclohexanone, and TiO2 particulate films were obtained by depositing these TiO2 particles with various sizes onto a glass or quartz substrate. The effect of the particle size and thickness on the photocatalytic properties of the films was evaluated via oxidative degradation of gaseous 2-propanol. The initial rate of 2-propanol degradation under UV light irradiation for the films deposited with 30 nm TiO2 particles increased with increasing film thickness up to 600 nm, and reached a saturated value above this film thickness. Photocatalytic activity for the films with thickness below 600nm was larger when smaller TiO2 particles were deposited onto the substrate, due to the increase in the surface area of the particulate films. Furthermore, saturated values of the photocatalytic activity for thick films were smaller for the films deposited with smaller particles, which is mainly attributed to the change in crystal form of the particles during the grinding treatment.

2-Propanol↗

PubMedDate not supplied

A monoclonal antibody recognizing apolipoprotein E peptides in systemic amyloid deposits.

A monoclonal antibody was produced by immunization of mice with a crude amyloid A (AA) fibril preparation. This antibody (YK-2), when used in immunohistochemical studies, showed positive staining of amyloid deposits in tissues from patients with systemic amyloidosis (three idiopathic, three myeloma-associated, five reactive, one familial amyloid polyneuropathy, and three dialysis-associated). Immunoblotting revealed that YK-2 reacted with 14,000 and 7,000 dalton components of AA fibrils and a 36,000 dalton component of normal human serum. Absorption with purified human apolipoprotein E abolished staining. This suggests that fragments of apolipoprotein E are a common constituent of amyloid fibril of diverse origins, and it can be a new marker for immunohistochemical studies of systemic amyloidosis.

Amyloidosis↗

PubMedDate not supplied

Further characterization of a monoclonal antibody recognizing apolipoprotein E peptides in amyloid deposits.

A monoclonal antibody (YK-2), which was previously established to react with apolipoprotein E (apoE) peptides in systemic amyloid deposits, was further characterized. Epitope of this antibody was determined to be the residue 221 to 230 of apoE. In comparison with polyclonal anti-apoE antibodies, this antibody showed strong reactivity with apoE peptides in amyloid fibril preparation but poor reactivity with native apoE protein or apoE in serum, indicating its usefulness for probing degraded apoE in amyloid deposits. Immunohistochemical studies resulted in strong reactivity for amyloid A and immunoglobulin light-chain deposits but weak for beta 2-microglobulin and beta amyloid (senile plaque) deposits. Although the association of apoE with amyloid is non-specific to the component peptide of amyloid fibrils, present findings suggest that the amount or degradation manner of apoE or the environment around the antibody epitope vary among types of amyloidosis.

Alzheimer Disease↗