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Biomedical subjects

O Kobayashi

Publications and source records attributed to O Kobayashi.

At least 163 records · Page 9Linked to original sources
PubMed1983

[Characterization of two choliocarcinoma cell lines and their sensitivity to MTX].

Both the sensitivity to MTX and hCG secretion were compared in two choriocarcinoma cell lines (BeWo and HCCM-5) and study on mechanisms about MTX-resistance was described. The uptake of nucleotides and protein precursors was decreased in dose-dependent manner in both cell lines when exposed to MTX, but HCCM-5 cells showed more sensitivity to MTX. In HCCM-5 cells, both hCG and hCG-beta levels in the medium were decreased with exposure to 10(-9)M MTX, but they tended to increase when exposed to higher concentration of MTX in contrast to the inhibition of 3H-thymidine uptake. However, in BeWo cells, an inverse relationship between the incorporation of 3H-thymidine and secretion of hCG was not clearly observed. The content of dihydrofolate reductase (DHFR) in HCCM-5 cells was about one-half of that in BeWo cells. Although the peak of 3H-MTX incorporation was observed at 120 minutes in both cell lines, HCCM-5 cells incorporated about 4 times higher 3H-MTX than BeWo cells. The difference of sensitivity to MTX between those two cell lines seems to be concerned with both the decrease of MTX transport and increase of intracellular DHFR levels.

Animals↗
PubMed1982

[Study on the rationale for chemotherapy of refractory choriocarcinoma].

The combination chemotherapy consisting of methotrexate (MTX), actinomycin D (ACD), and an alkylating agent was applied to the high risk patients refractory to MTX and/or ACD. The remission rate of the high risk group was about 70% and that of low risk patients was 100%. It is important to seek an effective chemotherapy for patients refractory to the above combined chemotherapy; therefore, we tried out the following regimens: (1) Quadritherapy with MTX, ACD, CPM and vincristine; (2) CHAMOMA protocol; (3) cis-platinum, bleomycin and vinblastine therapy; (4) ultra high dose MTX therapy and (5) the combination chemotherapy without MTX. The last regimen was designed based on the experimental data chemotherapy using nude mice.

Antineoplastic Agents↗
PubMed1982

[Studies on the recurrent trophoblastic disease].

We studied the remission and the recurrent of trophoblastic disease treated in our clinic, during 1973 to 1980. 1) The remission and recurrent rates of 168 cases were 91.1% (153/168) and 5.2% (8/153) respectively. In these percentages, high risk was 65.9% (29/44) and 20.7% (6/29), low risk was 100% (124/124) and 1.6% (2/124), choriocarcinoma was 58.3% (21/36) and 28.6% (6/21), invasive mole was 100% (44/44) and 0, and undetermined was 100% (88/88) and 2.3% (2/88). 2) The interval to recurrence: 5 cases appeared under a year, 3 cases did over a year. And remission rate of recurrent case was (4/8), high risk was (2/6), and low risk was (2/2). 3) HCG-beta titers when U-hCG decreased under the LH levels was higher until 3 months in the recurrent case of high risk than that unrecurrent, while we did not recognize any differences after 3 months. Therefore criteria of remission in high risk would occurred on continuous LH levels of U-hCG for 3 months. 4) High risk has been treated by 3 courses of additional chemotherapy, but that when hCG-beta titer over 1.0ng/ml require more chemotherapy.

Adult↗
PubMed1982

[Study for the experimental chemotherapy and clinical application (author's transl)].

Experimental chemotherapy has been studying with choriocarcinoma in nude mice transplanted from drug resistant patients. The following results: 1) the combined therapy with MTX and ACD was not always effective and in place of one of them, the combination of CPM was effective 2) addition of VCR was effective; were obtained. These results were applied to two patients in clinic. 1) The first patient failed to obtain complete remission by the course of ACD, MTX + ACD, and MTX + ACD + CPM (MAC) therapy. Then the combination therapy with ACD + CPM made her HCG titer regressed to negative immediately. She is free from disease now. 2) The HCG titer and pulmonary metastasis of the second patient showed resistance to MAC therapy, CHAMOMA therapy, and the combined therapy with MTX. The combination chemotherapy with ACD + CPM + VCR made her HCG titer become to regressed and the pulmonary metastasis reduce to 1/4 in size. The clinical application of the results from experimental chemotherapy was defined to be possible. The experimental model will contribute to establish the schedule of the rational chemotherapy for drug-resistant choriocarcinoma.

Adult↗
PubMed1981

[Characteristics of human choriocarcinoma transplanted in nude mice (author's transl)].

Experimental chemotherapy with choriocarcinoma transplanted in nude mice has been studying to improve the prognosis of drug resistant choriocarcinoma. In this paper the characteristics of transplanted tumors were presented. Two tumors, CC-HM-I (HM) and CC-I-JCK (JCK), were used. The characteristics of the tumors were studied in macroscopical findings, histological findings, growth curves, DNA amount analysis, LDH activity, alkaline phosphatase activity, and their isozyme patterns. Both tumors well maintained the characteristics of original and/or the beginning ones. Some differences between two tumors were pointed out. In morphology, HM was yellowish and hard tumor and the growth rate was rather slow. While, JCK was dark and soft tumor and contained a lot of bleeding and necrotic tissue. Its growth rate was quick and all of nude mice with JCK died of tumors around 50 days after transplantation. The serum level of HCG of HM was 75.8 +/- 2.8 ng/ml/g tumor and that of JCK was 117.4 +/- 6.2 ng/ml/g tumor. The good correlation between the tumor weight and the serum level of HCG was obtained in both groups. The activities of LDH and alkaline phosphatase in the tissues of JCK were about 3 times as higher as the one of HM. It was confirmed that the transplanted choriocarcinoma in nude mice was useful model for the study the nature of human choriocarcinoma and it will contribute to the establishment of the rational chemotherapy for drug resistant choriocarcinoma.

Animals↗
PubMed1981

[Experimental chemotherapy with drug-resistant choriocarcinoma transplanted to nude mice (author's transl)].

Serial transplantation in nude mice of human choriocarcinoma showed the drug resistance in clinic was succeeded and experimental chemotherapy has been studied to improve the prognosis of the patients with choriocarcinoma. The experimental tumors were two lines. CC-I-JCK (JCK) and CC-HM-I- (HM). In this paper, single and/or combination chemotherapy with methotrexate (MTX), actinomycin D (ACD), cyclophosphamide (CMP), and vincristine (VCR) were discussed. 1) Effects of the single agent: In JCK, the suppressive effects against tumor growth under administration of CPM or VCR, and some responses in histological finding were obtained. While, in HM, few suppressive effects against tumor growth and some responses in histological findings were obtained. 2) Effects of the combined agents: In JCK, the suppressive effects against tumor growth were as follows; nontreatment group less than MTX + ACD less than MTX + CPM less than MTX + ACD + CPM less than ACD + CPM less than ACD + CPM + VCR. The complete disappearance of tumors were gained under administration of the combination therapy with ACD and CPM. While in in HM, the effects were as follows; nontreatment group less than MTX + ACD less than ACD + CPM less than MTX + ACD + CPM less than MTX + CPM less than MTX + CPM + VRC. But no complete disappearance of tumor was obtained. 3) The good relationship between the results of experimental chemotherapy and the response of clinical patients who provided the tissues could be seen. It has been defined that the experimental chemotherapy with the tumors transplanted to nude mice in useful models for the establishment of rational chemotherapy for drug resistant choriocarcinoma.

Animals↗
PubMed1978

Monomer-dimer equilibria of a Bence Jones protein and its variable fragment.

The circular dichroic (CD) spectra of a type lambda Bence Jones protein (Tod), its variable (VL) fragment, and the constant (CL) fragment of a type lambda protein (Nag) were measured under various conditions. In the pH region from 5.5 to 7.5, the CD spectra of Tod protein with intact interchain disulfide bond (L(SS)) and and CL did not change with pH, while the spectra of Tod protein in which the interchain disulfide bond had been reduced and alkylated (L(RA)) and VL did not change with pH. The dimerization reactions of L(RA) and VL were studied by following the CD change with protein concentration. The CD spectrum of CL did not change with the protein concentration. The dimerization constant for L(RA) was 4 X 10(4) M-1 at at pH 7.5 and 25 degrees C, which was smaller than that for VL (1 X 10(5) M-1). The ellipticity at 278 nm for the L(RA) dimer was different from that for the L(SS) dimer and changed with pH. These findings indicate that the L(RA) dimer and L(SS) dimer have different conformations. The differences in the conformation and L-L interaction between the L(RA) dimer and L(SS) dimer are discussed on the basis of the conformations of VL and CL and the interactions between the paired domains.

Alkylation↗
PubMed1975

Acute renal insufficiency following hydrostatic pressure treatment: comments on technical procedure.

A man with a solitary bladder carcinoma suffered acute tubular necrosis following hydrostatic pressure therapy. The nephrotoxicity caused by antibiotics and/or the septicemic shock seems to be responsible. The animal experiment suggested changes in the technique: 1) the bladder should be overdistended via a Foley catheter with a rubber ballon at the tip to prevent a possible postoperative complication and 2) one should try to decrease rather than maintain the high intravesical pressure during overdistension to avoid bladder wall rupture. The overstretching of a blood vessel alone is quite sufficient to bring the anoxia upon the bladder tumor, which is verfied by the biophysical principle.

Acute Kidney Injury↗
PubMed1975

Exertional hemoglobinuria.

A 16 years old boy had a typical exertional hemoglobinuria after walking with his new leather shoes on. The attacks of hemoglobinuria were associated with the appearance of an unstable hemoglobin in red cells. A slightly decreased fragility curve by 24 hr incubated red cells, the increase of autohemolysis and the appearance of heat labile hemoglobin were observed after exertion. These findings support that exertional hemoglobinuria may be regarded as a transitory erythropathia.

Adolescent↗