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Biomedical subjects

T Ohnuma

Publications and source records attributed to T Ohnuma.

At least 91 records · Page 5Linked to original sources
PubMed1987

Comparative studies of human malignant mesothelioma in vivo, in xenografts in nude mice, and in vitro. Cell origin of malignant mesothelioma.

Several decades ago, it was reported that normal and malignant mesothelial cells were transformed into distinct cell types (epithelial to fibrous and fibrous to epithelial) when transferred to in vitro conditions. Those tissue culture data are still cited as evidence supporting that the mesothelial cell has multipotentiality of differentiation and the mesothelial cell is a sole precursor of malignant mesothelioma cells. Six cell lines of heterotransplanted human malignant mesothelioma in nude mice and one cell line of subcultured human malignant mesothelioma in vitro have been established. To establish the validity of the classic concept of multipotentiality of malignant mesothelioma, we studied malignant mesothelioma cells of the seven cases using in vivo cultures, xenografts in nude mice and an in vitro tissue culture, utilizing histology, histochemistry, immunocytochemistry and electron microscopy. The nature of the original malignant mesothelioma cells was clearly shown to be well preserved in both the heterotransplanted and subcultured cells. Data did not support earlier hypotheses that mesothelial cells are capable of differentiating into distinct cell lines. The mesothelial cell and the submesothelial connective tissue cells are the precursors of the neoplastic cells in malignant mesothelioma.

Aged↗
PubMed1987

Iatrogenic and idiopathic acute myelogenous leukemia: a comparison of clinical features and treatment complications.

We have compared the clinical and laboratory features as well as treatment complications observed in 6 patients with iatrogenic acute myelogenous leukemia (I-AML) with those of 26 patients with idiopathic acute myelogenous leukemia (AML). I-AML patients were significantly younger and their disease appeared less virulent on admission than in the AML patients. Following identical chemotherapy, hemorrhagic complications and the need for platelet support were found to be similar for both groups. Major infections, including systemic candidiasis and Gram-negative septicemias, occurred 3 times more frequently among I-AML than AML patients. More marked suppression and delayed regeneration of the bone marrow also occurred in I-AML patients. These observations and other factors, such as post-splenectomy state and inherent immune deficiency among surgically staged lymphoma patients as well as radiation induced immunologic impairment, may have contributed to the increased propensity to develop infection observed in this group of patients. Five of the 6 I-AML and 17 of the 26 AML patients achieved remission. We attribute the satisfactory outcome in our I-AML patients to treatment in a protective environment and availability of facilities for hematologic supportive care.

Adult↗
PubMed1987

Effects of doxorubicin and cisplatin on multicellular tumor spheroids from human lung cancer.

We tested the sensitivity to doxorubicin (DXR) and cisplatin (DDP) of multicellular tumor spheroids (MTS) developed from 2 human lung cancer cell lines; PC-10 squamous cell carcinoma and PC-6 small cell carcinoma. DDP was able to maintain its efficacy in MTS: PC-10 MTS were only 3-fold more resistant to DDP than in monolayer and in PC-6 cells DDP induced cell lethality was essentially unchanged irrespective of cells being in a monolayer or MTS. Atomic absorption spectrometry revealed that DDP uptake was essentially identical, irrespective of cells being in monolayer or MTS. DDP's efficient cell kill effects in MTS seems to be explained by its good penetration into the MTS core. In contrast to DDP, these 2 types of cells responded differently to DXR. Thus, PC-10 MTS became progressively more resistant to DXR when their size increased, whereas the susceptibility of PC-6 MTS tended to increase when the MTS grew larger. Fluorescent microscopic study revealed that prominent DXR fluorescence was observed only at the outer layer of PC-10 MTS. In PC-6 MTS, however, DXR fluorescence was diffusely seen in the entire MTS at low concentrations; nevertheless, owing to PC-6 cells' high sensitivity DXR was able to exert cell lethality. The differences in distribution of DXR fluorescence between PC-10 and PC-6 MTS were corroborated by flow cytometric analysis.

Cell Survival↗
PubMed1987

Effects of anticancer agents on the shedding of cells from human multicellular tumor spheroids.

We studied the effects of anticancer agents on the inhibition of cell shedding from the surface of multicellular tumor spheroids (MTS). MTS were produced from 2 human tumor cell lines; one melanoma and the other squamous cell lung cancer, by using liquid overlay culture technique. The cell shedding from the melanoma MTS was approximately 10-fold higher than the squamous cell carcinoma MTS. In the melanoma MTS, all 3 drugs studied - vincristine (VCR), doxorubicin (ADR) and cisplatin (DDP)-inhibited cell shedding and the degree of inhibition of cell shedding was drug concentration related. In the squamous cell carcinoma MTS, VCR was as active in inhibiting cell shedding as in the melanoma MTS, but ADR and DDP were less efficacious. When effects on cell shedding were compared with those on cell lethality, VCR produced inhibition of cell shedding at much lower concentrations than those producing cell kill effects. ADR and DDP produced cell lethality as effective as, or more effective than, inhibition of cell shedding. These data seem to parallel known effects of these agents on cell kill and inhibition of metastases. MTS may serve as an in vitro model for the study of cell shedding and metastasis.

Carcinoma, Squamous Cell↗
PubMed1986

Effects of cell density on drug-induced cell kill kinetics in vitro (inoculum effect).

The effects of cell density on drug-induced cell kill kinetics were studied by means of clonogenic assay using 3 human leukaemia-lymphoma cell lines. Mitoxantrone, daunorubicin, doxorubicin, vincristine and bleomycin were progressively less efficacious when cell density increased (positive inoculum effects), whereas the effects of cis-platin and carboplatin were not influenced by cell density. Inoculum effects were related to the kind of chemotherapeutic agents tested, irrespective of the type of cell lines used. Preincubation of mitoxantrone or doxorubicin in the presence of cells in high density resulted in decreases in the cytocidal activity, whereas the effects of bleomycin, vincristine and cis-platin were unaffected. These results show that cell density affects the biological effect of certain chemotherapeutic agents. Inactivation of drugs by high densities of cells partially explains this phenomenon.

Antineoplastic Agents↗
PubMed1986

Comparison of mitoxantrone and ametantrone in human acute myelocytic leukemia cells in culture and in bone marrow granulocyte-macrophage progenitor cells.

The cytocidal effects of mitoxantrone and ametantrone were compared in 3 human acute myelocytic leukemia (AML) cell lines by means of clonogenic as well as cell growth inhibition assay. The effects of these two agents were also compared on normal bone marrow granulocyte-macrophage progenitor cells (CFU-GM). Mitoxantrone was 10-20 fold more potent against AML cells than ametantrone. Longer exposure of cells to these agents resulted in increased cell kill, but with lesser efficiency. Both mitoxantrone and ametantrone were more cytocidal on normal bone marrow CFU-GM than on AML cells; mitoxantrone was approximately 2.5-fold and ametantrone nearly 10-fold more active against CFU-GM than against HL-60 AML cells.

Anthraquinones↗
PubMed1986

Folate requirements of methotrexate-resistant human acute lymphoblastic leukemia cell lines.

We studied the folate requirements of a human acute lymphoblastic leukemia cell line, MOLT-3, and methotrexate (MTX)-resistant sublines established in vitro. The requirement of pteroylglutamate (PGA) for optimal cell growth was different for each cell line. With increasing MTX resistance, there was progressive increase in PGA requirements, moving the PGA concentration-cell growth curve (dose-response curve) 1 log order of magnitude to the right. The increases in the requirement of 5-methyltetrahydrofolate (5-methyl-THF) by the resistant sublines were more pronounced than PGA requirement, moving the dose-response curve nearly 3 log orders in magnitude to the right. The concentrations in vitro of 5-methyl-THF required for optimal growth of the MTX-resistant sublines far exceeded the normal serum 5-methyl-THF concentrations known in humans. These observations show that MTX-resistant cell established in vitro in culture media containing PGA instead of 5-methyl-THF, a physiological folate, cannot be expected to grow in vivo. The collateral sensitivity of transport-impaired MTX-resistant sublines to 2,4-diamino-5-methyl-6-[(3',4',5'- trimethoxyanilino) methyl] quinazoline (trimetrexate, TMQ) was negated in the absence of PGA. With the addition of 5-methyl-THF, the parent cells became more resistant than the transport-impaired sublines to TMQ These data indicate that the collateral sensitivity of MTX resistant cells to the substituted 2,4-diaminoquinazoline is due to functional folate deficiency by virtue of the impaired transport of folate.

Biological Transport↗
PubMed1985

Doxorubicin plus cisplatin in the treatment of apudomas.

Twelve patients with advanced apudomas--six with carcinoid tumors, two with chemodectomas, two with pancreatic islet cell tumor, and one each of medullary carcinoma of the thyroid and paraganglioma of unknown primary--were treated with a combination of doxorubicin 50 mg/m2 and cisplatin 50 mg/m2 every 3 to 4 weeks. Biochemical markers were present in 8 of the 12 patients. Five of the 12 patients (3 with carcinoid and 2 with chemodectomas) responded with more than 50% regression of tumor size measured as hypothetical area. Three others (two with islet cell tumors and one with carcinoid) had clinical and/or biochemical improvements. A median duration of response was 6 months. Nausea, vomiting, and alopecia were universal. Mild or moderate leukopenia was the most frequent toxicity. No sustained nephrotoxicity was seen. The combination of doxorubicin and cisplatin provides a new palliative therapy for patients with APUD tumors.

Adolescent↗
PubMed1985

Biologic and pharmacologic effects of harringtonine on human leukemia-lymphoma cells.

Ten human leukemia-lymphoma cell lines were tested for the growth-inhibitory effects of harringtonine (HT). HT was most active against HL-60 acute promyelocytic leukemia cells and least active against DND-41 acute lymphoblastic leukemia cells, with a 70-fold differential activity. Sensitivity of the cell lines is, in decreasing order: HL-60 greater than RPMI-8402 greater than DND-39A congruent to ML-2 congruent to MOLT-3 congruent to KG-1 greater than Daudi congruent to NALL-1 greater than BALM-2 greater than DND-41. The cell lines with rapid cell growth tended to be more sensitive to HT. To further elucidate the selectivity of the differential sensitivity, uptake and release of HT were compared in HL-60 and DND-41 cells. Uptake of [3H]HT into HL-60 and DND-41 cells showed no difference; however, the binding of [3H]HT to cellular components was greater than 16-fold higher in HL-60 cells than DND-41 cells. There were also minor, but significant differences in the inhibition of [3H]leucine incorporation into proteins of these two cell lines in the presence of 1 microgram/ml HT. To test whether the biological effects of HT are related to the concentration of, or exposure time to, HT, KG-1 cells were exposed to HT for different periods of time and the growth-inhibitory effects were compared. Increasing exposure time from 1 h to 3 h resulted in a 100-fold decrease in concentration X exposure time (c X t) at ID50; from 3 h to 6 h, in a 20-fold decrease at ID70; and from 6 h to 24 h, in a 16-fold decrease at ID90. HT was not inactivated by cells up to 24 h. These results indicate that (a) the sensitivity of different cell lines to HT may be related to the degree of HT binding; and (b) the effects of HT are more dependent on exposure time than concentration. Continuous infusion is thus rational for clinical trials of this drug, and the degree of HT binding to leukemic cells may be predictive of clinical response.

Alkaloids↗
PubMed1985

Ultrastructural peroxidase cytochemistry of three established human myelogenous leukemia cell lines, HL-60, KG-1 and ML-2.

We studied the ultrastructural peroxidase cytochemistry of three established human acute myelogenous leukemia cell lines (HL-60, KG-1 and ML-2) to clarify the cytochemical differences and the differences in maturation/differentiation stages. HL-60 cells contained azurophil granules which exhibited strong peroxidase reaction. The more central region of individual granules is less reactive than the outer portion of these granules. The secretory apparatus of HL-60 cells, i.e. rough endoplasmic reticulum, perinuclear cisterna and Golgi apparatus, also contained peroxidase-reactive material. ML-2 cells contained azurophil granules with peroxidase reaction; however, nuclear membranes were peroxidase-negative and thin cisternae of rough endoplasmic reticulum exhibited only a faint peroxidase reaction. KG-1 cells were peroxidase-negative. From these findings KG-1 is classified as the least mature of the cell lines studied. ML-2 cells are considered early promyelocytes and HL-60 cells as late promyelocytes.

Cell Differentiation↗
PubMed1985

Combination chemotherapy with high-dose methotrexate, bleomycin, and cisplatin in management of head and neck squamous cell carcinoma.

Fifty-nine patients with stage IV head and neck squamous cell cancer were treated with an intensive induction chemotherapy consisting of high-dose methotrexate-leucovorin, bleomycin, and cisplatin. Forty-five patients had recurrent disease following surgery and/or radiation therapy. The response rate in this group was 22%, with a median response duration of 10 weeks and a median survival of 19 weeks. The median survival in responders was 20 weeks and in nonresponders 18 weeks. Fourteen previously untreated patients (13 T4 and one T2) received identical chemotherapy followed by radiation and/or surgery. The response to chemotherapy in previously untreated patients was impressively higher (93%). These patients had a median survival of 48 weeks, and 30% survived 2 years. The initial chemotherapy did not compromise the succeeding radiation therapy or surgery. Toxicities were frequent, but generally well tolerated. It is concluded that prior surgery and/or radiation therapy compromises the efficacy of subsequent chemotherapy in head and neck cancer. Responses to intensive chemotherapy prior to surgery and/or radiation therapy are excellent in patients with T4 tumors and provides a basis for further intensive treatment in attempts to augment cure rates.

Adult↗
PubMed1985

Phase 1 study of carboplatin in patients with advanced cancer, intermittent intravenous bolus, and 24-hour infusion.

We undertook a phase 1 study of Carboplatin (CBDCA) on an intermittent single intravenous (IV) bolus (schedule A) and a 24-hour continuous infusion schedule (schedule B). Hydration and forced diuresis were not performed. Patients were not premedicated for anticipated vomiting. Thirty-eight adult patients with solid tumors received a total of 71 courses. In schedule A, doses were escalated from 20 to 600 mg/m2. The dose-limiting toxicity was myelosuppression. At doses of 270 mg/m2 and higher, leukopenia and thrombocytopenia were reproducibly seen. The dose of 600 mg/m2 was the maximally tolerated dose, producing severe thrombocytopenia (platelet counts less than 30,000/microL). Other toxicities included a fall in hemoglobin levels and tolerable nausea and vomiting. Schedule B produced comparable hematologic and emetogenic toxicities to those in schedule A. In three patients audiograms became abnormal with high-frequency hearing loss without overt deafness. Two patients developed hypomagnesemia without irreversible renal dysfunction. Patients with poor performance status, preexisting renal dysfunction, a third fluid space, or bone metastases seemed to develop increased hematologic toxicity. The recommended phase 2 dose for good risk patients is 400 mg/m2 IV bolus and for poor risk patients 270 mg/m2 IV bolus. Responses were seen in one patient each with head and neck carcinoma (partial response), small cell lung cancer (minor response), and breast cancer (minor response).

Adult↗