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Biomedical subjects

M Akutsu

Publications and source records attributed to M Akutsu.

At least 37 records · Page 2Linked to original sources
PubMed1997

B cell malignancy and hepatitis C virus infection.

Italian authors report that hepatitis C virus (HCV) infection may be one of the causes of lymphoid malignancy such as non-Hodgkin's lymphoma (NHL) and Waldenström's macroglobulinemia (WM). To assess the relationship between HCV infection and B cell malignancy (BCM) in Japan, we analyzed HCV-RNA in 50 patients with BCM [25 cases of NHL, 4 of WM and 21 of multiple myeloma (MM)] and determined genotype of infected HCV(Okamoto's classification) using reverse transcription-polymerase chain reaction assay. Eight (16.0%) of 50 patients with BCM were HCV-RNA positive [HCV(+)], while no patients were HCV(+) in control group (18 patients of non-B cell NHL). Numbers of HCV(+) cases in each group examined were as follows; four (16.0%) in B cell NHL (genotype II/III/IV were 3/1/0, respectively), one (25.0%) in WM (genotype III) and three (14.3%) in MM (genotype II/III/IV were 1/1/1, respectively). All patients examined had no symptoms and signs suggesting vasculitis. The incidence of HCV infection in the patients with BCM was markedly higher than that (approximately 1%) of healthy blood donors in Japan. We also experienced four B cell NHL cases with splenic or hepatic origin in the course of chronic hepatitis C. These results implicate the association between persistent HCV infection and the occurrence of BCM.

Genotype↗
PubMed1996

In vitro schedule-dependent interaction between paclitaxel and cisplatin in human carcinoma cell lines.

The schedule-dependent interaction of paclitaxel and cisplatin was studied in four human carcinoma cell lines: non-small cell lung cancer, A549; breast cancer, MCF7; ovarian cancer, PA1; and colon cancer, WiDr cells. The cells were exposed simultaneously to the drugs for 24 h and sequentially to paclitaxel first for 24 h followed by cisplatin for 24 h, or vice versa, and then incubated in drug-free medium for 4 and 3 days, respectively. Cell growth inhibition was then determined by the 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenyltetrazolium bromide (MTT) reduction assay. The effects of drug combinations at the IC80 level were analyzed by the isobologram method. On simultaneous exposure to paclitaxel and cisplatin, additive and subadditive (slight antagonistic) effects were observed in A549, MCF7, and PA1 cells, while sub-additive and protective (antagonistic) effects were observed in WiDr cells. On sequential exposure to paclitaxel first, followed by cisplatin, additive effects were observed in all cell lines. On sequential exposure to cisplatin first, followed by paclitaxel, additive effects were observed in PA1 cells, while additive, sub-additive, and protective effects were observed in A549, MCF7, and WiDr cells. These findings suggest that the interaction of paclitaxel and cisplatin is schedule- and cell line-dependent. The optimal schedule of this combination may be paclitaxel first followed by cisplatin.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Schedule-dependent interaction between paclitaxel and 5-fluorouracil in human carcinoma cell lines in vitro.

We assessed the cytotoxic interaction between paclitaxel and 5-fluorouracil administered at various schedules against four human carcinoma cell lines, A549, MCF7, PA1 and WiDr. The cells were exposed simultaneously to paclitaxel and to 5-fluorouracil for 24 h or sequentially to one drug for 24 h followed by the other for 24 h, after which they were incubated in drug-free medium for 4 and 3 days respectively. In another experiment, the cells were exposed simultaneously to both agents for 5 days. Cell growth inhibition was determined by MTT reduction assay. The effects of drug combinations at IC80 were analysed by the isobologram. The cytotoxic interaction of paclitaxel and 5-fluorouracil was definitely schedule dependent. Simultaneous exposure to paclitaxel and 5-fluorouracil for 24 h showed mainly subadditive effects in A549, MCF7 and WiDr cell lines, whereas it showed additive effects in PA1 cells. Sequential exposure to paclitaxel followed by 5-fluorouracil showed additive effects in all cell lines. Sequential exposure to 5-fluorouracil followed by paclitaxel showed subadditive effects in A549, MCF7 and PA1 cells. Whereas it showed additive effects in WiDr cells. These findings suggest that maximum cytotoxic effects can be obtained when paclitaxel precedes 5-fluorouracil. Interestingly, the continuous (5-day) exposure to paclitaxel and 5-fluorouracil had additive effects in A549, PA1 and WiDr cells, indicating that the prolonged simultaneous administration of these agents may circumvent the antagonistic interaction produced by short-term simultaneous administration. These findings may be useful in clinical trials of combination chemotherapy with paclitaxel and 5-fluorouracil.

Antimetabolites, Antineoplastic↗
PubMed1996

[Effects of carboplatin combination with etoposide against leukemia/lymphoma cell lines].

We studied the effects of carboplatin in combination with etoposide in human B-cell lymphoma cell lines, BALL-2, Dauji and human T-cell leukemia cell lines, CEM, HSB and MOLT-3 cells. Cells were incubated for 3 days in the presence of carboplatin and etoposide, and the combined drug and cell growth inhibition was determined by MTT assay. The effects of drug combinations at ID80 were analyzed by an improved isobologram method (Steel and Peckham). In the combination of carboplatin with etoposide, the data points fell in the envelope of additivity (additive effect) in all five cell lines. Synergistic and antagonistic effects were not observed. These findings suggest that the combination of carboplatin and etoposide are as effective as expected.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Schedule-dependent interaction between paclitaxel and doxorubicin in human cancer cell lines in vitro.

The schedule-dependent interaction of paclitaxel and doxorubicin was evaluated in four human cancer cell lines. The cells were exposed simultaneously or sequentially to the two agents for 24 h, and were then incubated in drug-free medium for 4 and 3 days, respectively. The cell growth inhibitions were determined by the MTT assay. The cytotoxic interactions at the IC80 level were evaluated by the isobologram method of Steel and Peckham. In non-small cell lung cancer A549, breast cancer MCF7 and colon cancer WiDr cells, antagonistic effects were observed for the paclitaxel and doxorubicin combination on simultaneous exposure to the two agents and on sequential exposure to doxorubicin followed by paclitaxel, while additive effects were observed for the combination on sequential exposure to paclitaxel followed by doxorubicin. In ovarian cancer PA1 cells, additive effects were observed for all schedules. These findings suggest that sequential administration of paclitaxel followed by doxorubicin may be the most suitable sequence, while the simultaneous administration of the two agents and the sequential administration of doxorubicin followed by paclitaxel may result in less tumour cell kill than anticipated. Further preclinical and clinical studies are required to elucidate the relationship between paclitaxel and doxorubicin with regard to both antitumour activity and toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

[Effects of SN-38 in combination with other anticancer agents against Dauji cells].

To investigate the effects of CPT-11 in combination with other anticancer agents, a human Burkitt's lymphoma cell line, Dauji, was incubated for 3 days in the presence of SN-38 (active substance of CPT-11) and the combined drug and cell growth inhibition was determined by MTT assay. The effects of the drug combinations at ID50 were then analyzed by isobologram (Steel and Peckham). A supra-additive (synergistic) effect was observed for SN-38 in combination with carboplatin, cisplatin, cytosine arabinoside, and mitomycin C. An additive effect was observed for its combination with bleomycin, etoposide, 5-fluorouracil, and mitoxantrone. Additive and sub-additive (antagonistic) effects were observed in combination with doxorubicin. A Sub-additive effect was observed in combination with methotrexate and vincristine.

Antineoplastic Agents, Phytogenic↗
PubMed1994

[Severe infection in gastroenterological field; MRSA (methicillin resistant Staphylococcus aureus) enterocolitis].

There has been a rising trend in the number of methicillin-resistant Staphylococcus aureus (MRSA) infections in recent years, and postoperative MRSA enterocolitis has been on the increase. We conducted a nation wide questionnaire on postoperative enterocolitis from January 1988 to June 1990. Among the 169 institutes which replied, there were 126 cases of postoperative MRSA enterocolitis in 53 institutes. Most of the cases based on malignant disease, especially gastric cancer. Their onset began with diarrhea and fever, between the second and fifth postoperative days. 18 patients died, giving a mortality rate of 14.3%. Examination of the recent antibiotic susceptibility demonstrated that MRSA had rapidly acquired multiple drug resistance. It is important that every effort be made to protect against hospital infection.

Aged↗
PubMed1993

Effects of carboplatin in combination with other anticancer agents on human leukemia cell lines.

In vitro studies with drug combinations of carboplatin and other anticancer agents were carried out in MOLT-3 human lymphoblastic leukemia and HL-60 human promyelocytic leukemia cell lines. Cells were incubated for 3 days in the presence of various concentrations of carboplatin and other drugs and cell growth inhibition was determined by MTT assay. The antitumor effects of the drug combinations at ID50 were analyzed using an improved isobologram. In MOLT-3 cells, supra-additive (synergistic) effects were observed for carboplatin in combination with cytosine arabinoside, mitoxantrone and CPT-11. Additive effects were observed for combinations of carboplatin with bleomycin, daunorubicin, doxorubicin, etoposide, 6-mercaptopurine, and vincristine. Sub-additive and protective (antagonistic) effects were observed with methotrexate. Synergistic or antagonistic effects for combinations of carboplatin and CPT-11, cytosine arabinoside, mitoxantrone and methotrexate were also observed in HL-60 cells. These findings suggest that carboplatin has additive or synergistic cytotoxic effects with most of the agents tested. Determination of the usefulness of these drug combinations awaits appropriate in vivo experiments that should assess both tumorcidal effects and possible increased toxicity. The simultaneous administration of carboplatin and methotrexate would be of little effect. To find optimal schedules for this combination, further pre-clinical studies of various combinations schedule would appear to be warranted.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

[Treatment of 71 adult acute lymphoblastic leukemia].

From 1975 to 1989, 71 acute lymphoblastic leukemia patients aged 15 to 81 years (median 46 years) were treated at Jichi Medical School. Fifty-eight patients (81.7%) achieved complete remission (CR). Median CR duration was 219 days, and the probability of being in continuous CR at 3 years was 8.9%. Median survival was 462 days, and the probabilities of being alive at 3 and 5 years were 19.8% and 7.3%, respectively. The new regimen introduced from 1987 consisted of remission induction with L-asparaginase, daunomycin, vincristine and prednisolone, followed by intensive consolidation and maintenance. However, the treatment failed to improve outcome. The factor unfavorable for achieving early CR after first-line treatment regimen was the presence of myeloid antigen, and that for achieving final CR after second-line treatment regimen was advanced age. The factors unfavorable for remission duration were high leukocyte count and late CR. Those unfavorable for survival were advanced age and elevated blood urea nitrogen. Further improvement in the design of new protocols which include the use of several cytokines and autologous bone marrow transplantation may result in prolonged disease-free survival.

Adolescent↗
PubMed1992

Effects of CPT-11 in combination with other anti-cancer agents in culture.

CPT-11, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy camptothecin, is a newly developed water-soluble camptothecin derivative now undergoing phase-II evaluation. In an attempt to establish whether the combination of CPT-11 with other standard anti-cancer agents would be of any benefit, we studied the effects of CPT-11 in combination with 11 other anti-cancer agents on a human T-cell leukemia cell line, MOLT-3, in culture. We used both CPT-11 and SN-38 (active substance of CPT-11 in vivo), for our study. Cells were incubated for 3 days in the presence of 2 drugs (CPT-11 or SN-38 and another drug) and cytotoxic effects were determined by MTT assay. The effects of drug combinations on ID50 were analyzed by an improved isobologram method. Supra-additive and marginal supra-additive effects (synergism) were observed for CPT-11 in combination with cisplatin, cytosine arabinoside and mitomycin C. Additive effects were observed for its combination with amsacrine, bleomycin, doxorubicin, etoposide, 5-fluorouracil, mitoxantrone and vincristine. Alternate sub-additive and protective effects (antagonism) were observed for CPT-11 in combination with methotrexate. Similar tendencies were observed for SN-38 in combination with other agents. These results suggest that CPT-11 in simultaneous administration with a majority of anti-cancer agents has an advantage for cytokilling. Of these agents, cisplatin, cytosine arabinoside and mitomycin C are most suitable for simultaneous administration with CPT-11.

Antineoplastic Agents, Phytogenic↗
PubMed1992

The effects of ICRF-154 in combination with other anticancer agents in vitro.

We studied the effects of ICRF-154 in combination with 11 anticancer agents on four human leukaemia cell lines. Cells were incubated for 3 days in the presence of two drugs (ICRF-154 and one other), and cell growth inhibition was determined by MTT assay. Effects of drug combinations at the ID50 level were analysed using the isobologram method (Steel). In the lymphoblastic leukaemia cell lines, MOLT-3, HSB, and B-ALL, supra-additive effects were observed for ICRF-154 in combination with amsacrine, bleomycin, doxorubicin, and etoposide. Additive effects were observed for its combinations with cisplatin, CPT-11, cytosine arabinoside, 5-fluorouracil, mitomycin C, and vincristine. Sub-additive to protective effects were observed in combination with methotrexate. In an erythroleukaemia cell line, K-562, no drug showed supra-additive effects with ICRF-154, while sub-additive to protective effects were observed for ICRF-154 in combination with cisplatin and methotrexate. The other drugs showed additive effects with ICRF-154. These results indicate that the combined effects of ICRF-154 with other agents vary, depending on the cell line. Against lymphoid malignancies, ICRF-154 would be advantageous when administered simultaneously with many anticancer agents. Of such agents, amsacrine, bleomycin, doxorubicin, and etoposide are the most suitable, while methotrexate is least suitable for such combined treatment.

Antineoplastic Agents↗
PubMed1992

[Hospital acquired infection in surgical field and its countermeasure present situation of anaerobes, P. aeruginosa and MRSA infection].

The important organisms of hospital acquired infection in surgical field are anaerobes, P. aeruginosa and MRSA. From 1977, isolation frequency of anaerobes from pus has been increasing remarkably and it became 60% in 1978. The isolation rates of P. aeruginosa increased 20 to 30%. Since 1988, the incidence of isolation of MRSA has increased markedly. Almost of all the coagulase typing of MRSA were type II, and it suggested the possibility of hospital infection. In 1988, high antimicrobial activity against MRSA was observed with vancomycin, imipenem, minocycline and new quinolones, but in 1990 the multiresistant strains against imipenem, minocycline and new quinolones were increased. Among the various antimicrobial agents examined, vancomycin demonstrated the strongest activity to MRSA. The symptomatic infections were postoperative enterocolitis, respiratory infection, biliary tract infection and wound infection. The most severe symptom was observed in MRSA enterocolitis. We conducted a nation wide questionnaire of postoperative enterocolitis from January 1988 to June 1990. 169 institutes replied, and 126 cases were involved in postoperative MRSA enterocolitis in 53 institutes. Eighteen cases died, and mortality rate was 14.3%. In the treatment of MRSA infection vancomycin was the most effective antibiotics. It is the most important to prevent nosocomial infection.

Anti-Bacterial Agents↗
PubMed1992

Effects of mitoxantrone in combination with other anticancer agents on a human leukemia cell line.

To investigate the effects of mitoxantrone in combination with other anticancer agents, a human T-cell leukemia cell line, MOLT-3, was incubated for 3 days in the presence of two drugs (mitoxantrone and the combined drug) and cell growth inhibition was determined by assay with 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazonium bromide. The effects of drug combinations at doses giving 80% inhibition (ID80) were analyzed by an improved isobologram method. A supra-additive (synergistic) effect was observed for mitoxantrone in combination with amsacrine, cisplatin, or cytosine arabinoside. An additive effect was observed for its combination with bleomycin, doxorubicin, etoposide, 5-fluorouracil, mitomycin C, 6-mercaptopurine, or vincristine. A sub-additive (antagonistic) effect was observed for its combination with methotrexate. These data suggest that mitoxantrone, administered simultaneously with any one of a majority of anticancer agents we studied, is advantageous for cytokilling. Of the anticancer agents tested, amsacrine, cisplatin, and cytosine arabinoside are the most suitable for combination with mitoxantrone, and these combinations are worthy of clinical investigation. Methotrexate in our system is inappropriate for simultaneous administration with mitoxantrone. These data should provide useful information for the establishment of clinical protocols involving mitoxantrone.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Effects of amsacrine in combination with other anticancer agents in human acute lymphoblastic leukemia cells in culture.

Effects of amsacrine in combination with other anticancer agents at ID80 were evaluated by cell growth assay using a human T-cell leukemia cell line (MOLT-3). The data were analyzed with the aid of an improved isobologram, using the concept of an envelope of additivity. A supra-additive effect was observed for amsacrine in combination with cytosine arabinoside and mitoxantrone. An additive effect was observed in its combinations with bleomycin, CPT-11, cisplatin, daunorubicin, doxorubicin, etoposide, 5-fluorouracil, homoharringtonine, mitomycin C, or vincristine. 6-Mercaptopurine had an additive effect with amsacrine at ID80 but a sub-additive to protective effect at ID90. A sub-additive to protective effect was shown for amsacrine in combination with methotrexate. These data suggest that cytosine arabinoside and mitoxantrone are the best of the anticancer agents we studied for use in combination with amsacrine. Bleomycin, cisplatin, CPT-11, doxorubicin, cytosine arabinoside, homoharringtonine, mitomycin C, and vincristine also yielded favorable results when administrated simultaneously with amsacrine. Simultaneous administration of amsacrine with 6-mercaptopurine and methotrexate is not appropriate. If amsacrine is combined with 6-mercaptopurine and methotrexate, other suitable schedules should be explored. These results may provide a rationale for the design of clinical protocols combining amsacrine with other anticancer agents.

Amsacrine↗
PubMed1991

Schedule-dependent synergism and antagonism between methotrexate and 6-mercaptopurine in a human acute lymphoblastic cell line.

We studied the combined cytotoxic effects of methotrexate and 6-mercaptopurine (6-MP) on a human acute lymphoblastic cell line (MOLT-3) in vitro according to various schedules. The combined effects were analysed with improved isobologram using the concept of additivity. Simultaneous and continuous exposure (72 h) to these two agents had subadditive to protective effects (antagonism). Partial simultaneous exposure to methotrexate (5 h) and 6-MP (72 h) showed additive to protective effects. Sequential exposure to methotrexate (5 h) followed by 6-MP (72 h) had an additive effect at 0 h and a supra-additive effect (synergism) at 3 h and 19 h intervals. Therefore, it would seem to be better to avoid the simultaneous administration of methotrexate and 6-MP when these two drugs are used in combination. Sequential administration of methotrexate first, followed by 6-MP at short intervals, is recommended.

Cell Division↗
PubMed1991

Multipotent and committed CD34+ cells in bone marrow transplantation.

In order to study the role of CD34+ cells in hematological recovery following bone marrow transplantation (BMT), bone marrow cells stained with HPCA-1 (CD34) and MY-9 (CD33) monoclonal antibodies were analyzed by using a fluorescence-activated cell sorter on or about days 14 and 28, as well as at later times, following BMT in 6 recipients. Single cell cultures of CD34+ cells were also performed to evaluate their in vitro hematopoietic function. CD34+ cells were detectable in bone marrow cells on day 14. More than 80% of CD34+ cells co-expressed the CD33 antigen, and macrophage (Mac) colony-forming cells predominated among total colony-forming cells of CD34+ cells. In normal bone marrow cells, CD34+, CD33+ cells amounted to about 40% of CD34+ cells, and the incidences of erythroid bursts, granulocyte/macrophage (GM) colonies, and Mac colonies were similar to each other. After more than 10 weeks, CD34+, CD33- cells gradually recovered, as erythroid burst colony-forming cells increased following GM colony-forming cells. This phenomenon was well-correlated with the time course of peripheral blood cell recovery. CD34+, CD33+ cells as committed progenitors and CD34+, CD33- cells as multipotent stem cells have distinctive biological behaviors in BMT.

Antibodies, Monoclonal↗
PubMed1991

Host range mutant of human immunodeficiency virus type 1: modification of cell tropism by a single point mutation at the neutralization epitope in the env gene.

We have isolated a variant of human immunodeficiency virus type 1 (HIV-1) which is highly infectious to fibroblastlike cells (BT cells) derived from human brain as well as CD4-positive T cells. This variant HIV-1, named HIV[GUN-1V], was obtained by infecting BT cells with a prototype HIV-1 isolate, named HIV[GUN-1WT], which is highly infectious to T cells but barely infectious to BT cells. HIV[GUN-1V] infects BT cells productively and this infection appeared to be mediated by CD4. To elucidate the viral gene responsible for the host range difference between the variant and prototype HIV-1s, we cloned and analyzed the provirus genomes of the two viruses. Examination of the infectivities of BT cells by various recombinant viruses and analyses of the nucleotide sequences of HIV[GUN-1V] and HIV[GUN-1WT] showed that a single nucleotide exchange was responsible for their difference in infectivity of BT cells: HIV[GUN-1V] contains a thymine residue instead of the cytosine residue in HIV[GUN-1WT] at position 931 of the env coding sequence. Replacement of cytosine by thymine at this position of the env coding sequence of the HIV[GUN-1WT] genome induced the ability to infect BT cells. The base exchange at this position was expected to change amino acid 311 of the envelope glycoprotein, gp120, from proline to serine, which is located in a variable region containing type-specific immunodominant epitopes. Thus, HIV[GUN-1V] acquired a wider host range than HIV[GUN-1WT] by a single point mutation in the env gene.

Amino Acid Sequence↗