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Biomedical subjects

K Aiba

Publications and source records attributed to K Aiba.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Phase I study of paclitaxel].

Paclitaxel, a novel antimicrotubule agent that enhances tubulin polymerization and microtubule stability, was administered as a 24-hour infusion in a phase I study. Twelve patients received 32 courses at 50, 100, 150, and 200 mg/m2. A premedication regimen of dexamethasone, diphenhydramine, and ranitidine was used to prevent the acute hypersensitivity reactions (HSRs). The dose-limiting factor was leukopenia (granulocytopenia) associated with Grade 4 infection. The maximum tolerated dose was 200 mg/m2. Other non-hematological effects included peripheral neuropathy, myalgia, alopecia, and elevations of transaminase and alkaline phosphatase. Severe HSRs were not observed. The paclitaxel plasma concentration declined with a half-life of 10.0 to 24.9 hours. Excretion into urine within 72 hours was in the range of 7.28 to 11.34% of paclitaxel dosage. Two patients with breast cancer at the 200 mg/m2 dose level had partial responses. The recommended dose of paclitaxel for phase II study, when administered as a 24-hour infusion, is considered to be 150 mg/m2 every 3 weeks.

Adolescent↗
PubMed1994

[Antitumor effect of SN-38, active form of CPT-11, on human colorectal cancer cell line].

The in vitro sensitivity testing for four human colorectal cancer cell lines to seven chemotherapeutic drugs including CPT-11, derivative of camptothecin, and its active form SN-38 were determined. MTT assay revealed that SN-38 was the most active for all four cell lines tested and its IC50's were very close to its clinically achievable plasma concentration. Relationship between exposure time and cytocidal effect of SN-38 was also investigated using MTT assay, topoisomerase-I (Topo-I) immunoblot analysis and DNA relaxation-assay, showing that IC50 value, Topo-I protein and Topo-I activity were decreased soon after the administration of SN-38 and reached to the plateau level at 24 hours. We conclude that SN-38 is very potent for colorectal cancer and the optimal schedule of CPT-11 can be the more continuous form of administration capable of as long as 24 hours exposure of its active metabolite, SN-38.

Antineoplastic Agents, Phytogenic↗
PubMed1994

[Detection of thymidylate synthase mRNA in 5-fluorouracil resistant human colon adenocarcinoma cells].

To investigate the resistance against 5-fluorouracil (FU), thymidylate synthase (TS) mRNA level was measured by reverse transcription PCR (RT-PCR) technique and quantitated by a competitive-PCR method in human colon adenocarcinoma cell line, SNU-C1 and its FU resistant cell line, C1/FU. Using a set of primers covering 3'-untranslated region of mRNA, PCR products were amplified from cDNAs prepared from both SNU-C1 and C1/FU. However, only a cDNA extracted from C1/FU was amplified in a stationary growth phase. Then, the amount of mRNA was quantitated by competitive-PCR technique in both cell lines using another set of primer enable to amplify product in both stationary and logarithmic cell growth phase. The amount of mRNA in C1/FU was four times more than that of C1. The gene level in TS gene in genome DNA in these cell lines were not different incidentally. These data suggest that TS mRNA was more increased and can be more stable in C1/FU, accounting for FU resistance.

Adenocarcinoma↗
PubMed1993

Molecular cloning and characterization of two genes encoding gp138, a cell surface glycoprotein involved in the sexual cell fusion of Dictyostelium discoideum.

The sexual development of cellular slime molds is initiated by acquisition of sexual fusion competence of myxamoeboid cells. During the acquisition of fusion competence in NC4 and HM1 strain cells of Dictyostelium discoideum, opposite in mating types, a glycoprotein gp138, relevant to sexual cell fusion, is expressed on the cell surfaces of both the strains. To investigate the mechanisms controlling cell fusion, gp138 was purified and its N-terminal amino acid sequence was determined. An oligonucleotide with sequence predicted from the amino acid sequence was synthesized to isolate the gene encoding gp138. Two genes, referred to as GP138A and GP138B, were then cloned. They contain the region which encodes the N-terminal amino acid sequence of the gp138 protein and their structure is very similar on the whole. The C-terminal portion of the predictive polypeptides produced by the genes is highly hydrophobic and proline rich. It has homology with a portion of gp80, a glycoprotein for cell-cell adhesion, and PsA, a glycoprotein specific for prespore cells, reported previously in D. discoideum. The expression of GP138A is greater than that of GP138B. The mRNA of GP138A is expressed at the time of acquisition of fusion competence of cells during cultivation but the mRNA of GP138B is not.

Amino Acid Sequence↗
PubMed1993

Distribution of gp138, a cell surface protein responsible for sexual cell fusion, among cellular slime moulds.

Sexual cell fusion occurs between NC4 and HM1, heterothallic strains of Dictyostelium discoideum. Several cell surface proteins relevant to the process have been identified. One of them, gp138, exists in fusion-competent cells of both NC4 and HM1, and is considered to be more concerned with membrane fusion than gamete recognition. In this study, we raised monoclonal antibodies against gp138 and examined gp138 distribution among strains and species of cellular slime moulds to confirm its importance in sexual cell fusion. All heterothallic and bisexual D. discoideum strains examined were found to possess gp138, while asexual and homothallic strains lacked it. The anti-gp138 monoclonal antibody detected several distinct proteins in homothallic strains and one in an asexual strain. Some of the former proteins appeared together with the increase in binucleated cells. Cells of Dictyostelium mucoroides and Polysphondylium pallidum did not possess proteins reactive to the monoclonal antibody. These results indicate that gp138 is common among, but restricted to, cross-matable strains of D. discoideum. Our results also support previously published molecular phylogenetic studies which suggest that homothallic and asexual strains of D. discoideum are remote from other strains of D. discoideum but are less distantly related to them than other species are.

Animals↗
PubMed1993

Antisense RNA inactivation of gp138 gene expression results in repression of sexual cell fusion in Dictyostelium discoideum.

A glycoprotein, gp138, is implicated in the sexual cell fusion of Dictyostelium discoideum. We previously cloned and sequenced the two genes encoding the gp138 protein, GP138A and GP138B (Fang et al. (1993) Dev. Biol. 156, 201-208). Here, we have constructed a vector producing antisense RNA for the gp138 genes and have transformed the vector into Dictyostelium cells. The transformed cells showed a reduction in the amounts of gp138 mRNA and protein and their sexual cell fusion activity was considerably repressed.

Animals↗
PubMed1992

Fusion-inhibiting monoclonal antibodies and their relevant antigens in relation to sexual process of Dictyostelium discoideum.

Sexual cell fusion occurs between NC4 and HM1, the heterothallic strains in Dictyostelium discoideum. Cells of these strains are fusion incompetent when cultured on agar plates in the light and become fusion competent upon cultivation in a liquid medium in darkness. Two cell-surface components, gp70 and gp138, have been identified and characterized as being relevant to sexual cell fusion. Both are glycoproteins, and the former is detected only in fusion-competent HM1 cells, while the latter is detected both in fusion-competent HM1 and fusion-competent NC4 cells. We therefore suspect gp 70 to be responsible for cell recognition and gp138, for membrane fusion. Therefore, NC4 cells are expected to possess specific surface molecule(s) that can be recognized by HM1 cells. In the present study, we raised monoclonal antibodies (mAbs) against membrane fractions of NC4 cells and selected fusion-inhibiting mAbs to identify novel molecules related to sexual cell fusion in D. discoideum. Out of the five mAbs we obtained three, DE1, GG6, and HH9, were characterized. DE1 recognized antigens that specifically existed in fusion-competent NC4 cells but not in fusion-incompetent NC4 or HM1 cells. GG6 recognized cell-surface proteins with approximate molecular weights of 125 and 32 kDa in both fusion-competent NC4 and fusion-competent HM1 cells. In addition GG6 also recognised other proteins commonly present in fusion-incompetent cells. The 125 kDa protein appeared to be the same as gp138. The epitope recognized by HH9 was sodium dodecyl sulfate (SDS)-sensitive.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[High-dose thio-TEPA with escalating doses of epirubicin and autologous hematopoietic stem cell transplant for refractory cancers].

We studied high-dose chemotherapy with autologous hematopoietic stem cell transplant for patients (pts) with non-Hodgkin's lymphoma (NHL) and breast cancer (BC) refractory to conventional therapies. The conditioning regimen consisted of thio-TEPA 6 mg/kg/day for 3 consecutive days with escalating doses of epirubicin (EPI) in dose steps of 120, 150, 180 and 210 mg/m2 on day 1. Mucositis was dose limiting toxicity at 210 mg/m2 on this regimen, and the recommended dose of EPI was judged to be 180 mg/m2. No cardiotoxicities were observed. There were 3 with complete responses (CR), one partial response (PR) in pts with NHL, 3CR and 5PR in pts with BC. The median duration of response was 8 months (mos) and 4 mos, respectively. Hematological recovery was significantly earlier in the pts receiving both autologous bone marrow transplant (ABMT) and peripheral blood stem cell transplant (PBSCT) than ABMT alone. This approach made it possible to overcome the prolonged PLT recovery, which was one of the major problems on ABMT.

Adolescent↗
PubMed1992

[Phase I and pharmacokinetic study of SM-5887 by 5-day schedule].

Pharmacokinetics of SM-5887, a new totally synthetic anthracycline derivative, was studied in a phase I setting by 5-day schedule. The maximum tolerated dose was 25 mg/m2/d (total dose: 125 mg/m2/body) and the dose-limiting toxicity was myelosuppression which was consistent with the results of the phase I study by a single dose. In terms of subjective side effects, decreased nausea/vomiting and increased stomatitis were observed. In pharmacokinetic study, AUC of active form of SM-5887 increased on day 5 compared to that day 1. This result suggested that 5-day schedule of SM-5887 produced an accumulation of the active form. Five-day treatment schedule of SM-5887 seems to be more tolerable and further clinical study was recommended.

Adult↗
PubMed1991

A case with athetosis, mental retardation, deafness, and pachygyria.

A 6-year-old girl with pachygyria was presented. Regions of pachygiria were seen in the frontal, temporal, and parietal areas in vivo by magnetic resonance imaging. She showed athetosis, mental retardation, deafness, short stature, and microcephalus, but did not show epilepsy. A combination of these symptoms may be a new clinical entity, caused by undetermined prenatal events.

Athetosis↗
PubMed1991

The transient appearance of small blastoid cells in the marrow after bone marrow transplantation.

Of 14 patients who underwent allogeneic or syngeneic bone marrow transplantation, 6 had a transient appearance of small blastoid cells in the bone marrow after transplantation. Most of these patients (11) had leukemia, although 3 had severe aplastic anemia. The cells were 8-18 micron in diameter and had scant cytoplasm and dense nuclei with smooth, homogeneous chromatin. They often had distinct nuclear clefts. These cells constituted 4.0-21.3% of the total number of bone marrow cells. They were not reactive with peroxidase, alpha-naphtyl butylate esterase, naphthol AS-D chloroacetate esterase, or periodic acid-Schiff stains. Immunocytochemical analysis revealed that the small blastoid cells expressed terminal deoxynucleotidyl transferase, Ia-like, CD19, and CD10 antigens and cytoplasmic mu heavy chains, indicating a precursor B-cell phenotype. CD20 antigen was not expressed on these cells. The data suggest that cytoplasmic mu may be expressed earlier than CD20 antigen in the differentiation of B-cell lineage. The morphologic, cytochemical, and immunophenotypic characteristics did not distinguish these nonneoplastic cells distinctly from leukemic lymphoblastic cells. The increase of small blastoid cells was a transient and self-limited phenomenon, in contrast to that of neoplastic blasts. These cells should be recognized as a common component of the bone marrow of marrow transplant recipients. The significance and role of these cells in immune recovery and hematopoiesis remain uncertain.

Bone Marrow↗
PubMed1991

Magnetic resonance imaging in children with spastic diplegia: correlation with the severity of their motor and mental abnormality.

Magnetic resonance imaging (MRI) findings for 34 children with spastic diplegia, examined between two and 10 years of age, were analysed. Dilatation of the trigone, atrophy of the peritrigonal white matter and prominent deep cortical sulci were seen. On T2-weighted images, periventricular high-intensity areas in the white matter adjacent to the trigones and bodies of the lateral ventricles were seen in many children. These MRI features may reflect the pathological changes of periventricular leukomalacia in children with spastic diplegia. Among the MRI findings, only the amount of white matter correlated with severity of disability: white matter reduction corresponded to the more severe motor disabilities.

Brain↗
PubMed1991

Evaluation of prognostic factors for 233 patients with recurrent advanced breast cancer.

We analyzed possible prognostic factors in 233 patients with recurrent advanced breast cancer treated primarily by adriamycin, cyclophosphamide and ftorafur (ACF) therapy and ACF modifications. The patients were in the Cancer Institute Hospital from 1977 to 1986, and were followed-up until 1989. In terms of chemotherapeutic response, complete and partial responses were observed in 31 (13%) and 100 (43%) patients, respectively. The overall median survival from the beginning of chemotherapy was 20.3 months. The factors evaluated were response to chemotherapy, performance status (PS), age, disease-free interval (DFI), menopausal status, number of metastatic sites (step classification), presence or absence of liver metastasis, presence or absence of malignant effusion, and presence or absence of prior radiotherapy. Out of the nine factors, response to chemotherapy, PS, age, DFI and liver metastasis were significant factors affecting survival in univariate analysis, and multivariate analysis of these five factors revealed the survival to be markedly affected by response to chemotherapy (P less than 0.00001), PS (P = 0.00001) and DFI (P less than 0.00001).

Adult↗
PubMed1988

[Biochemical modulation of 5-fluorouracil by high-dose leucovorin].

The biochemical modulation of 5-fluorouracil (FU) by using it in combination with leucovorin (LV) is reviewed. One of the mechanisms of action of FU is inhibition of thymidylate synthase (TS), a critical enzyme in the de novo synthesis of thymidylate required for DNA repair and synthesis. In the presence of 5, 10-methylene tetrahydrofolate, 5-fluoro-deoxyuridine monophosphate (FdUMP), which is an active nucleotide of FU, forms a ternary complex with TS, resulting in enzyme inhibition. The rationale for the use of LV with FU is to increase of formation and stability of catalytically inactive ternary complexes. In clinical trials, the dose schedules of 500 mg/m2 iv bolus or 500 mg/m2 continuously iv infusion is frequently used in order to obtain an ideal plasma concentration of active LV metabolites. Preliminary clinical trials using the combination of FU and LV appear to be capable of increasing of the clinical activity of FU for colorectal and breast cancers. Several randomized studies have supported the increase in response rates seen in the uncontrolled trials but additional studies are required to demonstrate a positive impact on the survival of treated patients.

Chemical Phenomena↗
PubMed1987

Antimetabolites.

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Animals↗