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T Ohno

Publications and source records attributed to T Ohno.

1,022 records · Page 57Linked to original sources
PubMedDate not supplied

MEK and p38MAPK inhibitors potentiate TNF-alpha induced apoptosis in U937 cells.

BACKGROUND: TNF-alpha is one of the key inflammatory cytokines and it modulates various events through several pathways. U937 myelomonocytic leukemia cells are sensitive to TNF-alpha and about 20% of these cells undergo apoptosis within 6 hours after treatment. Co-treatment of these cells with actinomycin D or cycloheximide enhances TNF-alpha induced apoptosis, suggesting that some TNF-alpha-derived signals can augment apoptosis. We investigated whether mitosis-activating protein kinases (MAPKs) had an influence on TNF-alpha induced apoptosis. MATERIALS AND METHODS: U937 cells were treated by TNF-alpha with or without MEK or p38MAPK inhibitors. Apoptosis was assessed morphologically by fluorescence microscopy and caspase-3 was studied by immunoblotting. Expression of apoptosis-inhibitory proteins was studied by RT-PCR whilst the activation of JNKs was investigated by detecting their phosphorylation. RESULTS: TNF-alpha treatment induced apoptosis in about 23% of the cells, while pretreatment with a MEK inhibitor (PD98059) caused 69% of the cells to undergo apoptosis. The inhibition of p38MAPK by SB203580 scarcely enhanced apoptosis, although another p38MAPK inhibitor (PD169316) induced apoptosis in 37% of the cells. Simultaneous pretreatment of cells with PD98059 and PD169316 resulted in the highest level of TNF-alpha induced apoptosis and 90% of the cells underwent apoptosis after 6 hours. In cells pretreated with PD98059 plus PD169316, caspase-3 was completely cleaved at 6 hours and early induction of c-IAP2/HIAP 1 mRNA was not observed. JNKs showed rapid and extensive phosphorylation in these cells. CONCLUSION: TNF-alpha induced apoptosis was potentiated by the inhibition of either MEK alone, or MEK plus p38MAPK, suggesting that the MAPK pathway may be a promising target for cancer therapy.

Apoptosis↗
PubMedDate not supplied

Serum stimulation and cell density regulate the proliferation of AsPC-1 cells through control of cyclin E and p27KIP1 expression.

BACKGROUND: Cellular proliferation in normal cells is tightly regulated by environmental conditions. Growth factors stimulate proliferation while cell confluence inhibits it. Human pancreatic cancer AsPC-1 cells were believed to escape from these restrictions because they possessed several mutations which promote cell proliferation. In this study, we focused on the relationships between growth conditions and the proliferation of AsPC-1 cells. MATERIALS AND METHODS: AsPC-1 cells were cultured under several growth conditions and the proliferation of cells was studied by incorporation of 3H-thymidine. The alterations of cell-cycle-related genes were studied by immunoblotting. RESULTS: By four consecutive days in culture, the nucleotide incorporation of AsPC-1 cells was markedly suppressed and the suppression was overcome by medium change or reduction of cell density. The induction of cyclin D1 by serum stimulation was observed, concomitant with the transient activation of extracellular signal-regulated kinases (ERKs). The most prominent changes of cell-cycle-regulating genes following consecutive culture or serum reduction were the down-regulation of cyclin E and the induction of p27KIP1. The down-regulation of cyclin E was more sensitive to cell density, while the induction of p27KIP1 was regulated by both increased cell density and reduction of serum. The down-regulation of p27KIP1 was caused by protein degradation. CONCLUSIONS: The proliferation of AsPC-1 cells was still controlled by cell density and serum stimulation; nevertheless, the cells possessed several oncogenic mutations. These results may provide a rationale for modifying the growth environment for treatment of pancreatic cancers.

Adenocarcinoma↗
PubMedDate not supplied

Transduction of thymidine phosphorylase cDNA facilitates efficacy of cytosine deaminase/5-FC gene therapy for malignant brain tumor.

The in vivo gene delivery of E. coli cytosine deaminase (cd) cDNA and systemic 5-fluorocytosine (5-FC) administration have been studied extensively because of their clinical relevance to cancer gene therapy. This approach has the potent advantage of a stronger bystander effect compared to the previous thymidine kinase suicide gene system of the herpes simplex virus. However, 5-fluorouracil (5-FU), an active metabolite in cd with 5-FC therapy, is not always effective for every type of tumor since the enzymes responsible for further drug metabolism vary significantly in each tissue. In this study, we aimed to increase the sensitivity of 5-FU by transduction of thymidine phosphorylase (dThdPase) cDNA into brain tumor cells. After retroviral transfer of the cDNA, we obtained 9L murine gliosarcoma cells showing stable expression of the target enzyme (9L-dThdPase). The growth of the cells was identical to wild type (9L-WT) or control-vector transfected (9L-Neo) cells in vitro. Sensitivity to 5-FU was increased in 9L-dThdPase cells. After the adenoviral delivery of cytosine deaminase gene into these cells, 9L-dThdPase cells also demonstrated an increased sensitivity to 5-FC. Moreover, we showed that transduction of dThdPase cDNA prolongs the survival of animals bearing intracerebral tumors after experimental in vivo cytosine deaminase gene therapy. These results suggest that transduction of thymidine phosphorylase may be a beneficial approach to increasing the efficacy of cd/5-FC suicide gene therapy in certain types of tumor.

Adenoviridae↗
PubMedDate not supplied

Flow cytometric and Ki-67 immunohistochemical analysis of cell cycle distribution of cervical cancer during radiation therapy.

BACKGROUND: Little is known about the cell kinetics of human solid tumors during radiation therapy. MATERIALS & METHODS: Thirty one patients with cervical squamous cell carcinoma were analyzed by flow cytometry and immunohistochemical staining with Ki-67 antibody for tumor cell kinetics in the early period of radiation therapy. RESULTS: The G0/G1 fraction was significantly larger in stage 3 disease than in stage 2 disease. During radiation therapy, a decrease in the G0/G1 fraction and an increase in the S fraction were observed in stage 3 but not in stage 2 disease. Two reversal patterns of change in the cell cycle appeared in the early period of radiation therapy. The S phase fraction decreased significantly as the G0/G1 fraction of pre-treatment tumors became smaller than 70%, whereas it increased as the G0/G1 fraction became larger than 70%. The S fraction decreased significantly as Ki-67 growth fractions of pre-treatment tumors became greater than 30%, but on the contrary, it increased as the Ki-67 growth fraction became smaller than 30%. Only 2 of 23 patients showed a significant increase of the G2M fraction, reflecting the presence of the G2 block. The Ki-67 growth fraction increased about 26 % at 9 Gy compared with the growth fraction before treatment. Tumors which responded well showed higher G0/G1 fractions and lower S fractions than those which responded badly. CONCLUSION: The change of cell cycle parameters of the tumors during radiation therapy suggests that two reversal patterns of changes in cell kinetics take place in the early period of radiation therapy, which may have a potential impact in the modification of radiation therapy.

Adult↗
PubMedDate not supplied

Cytotoxic activity of gallic acid against liver metastasis of mastocytoma cells P-815.

Gallic acid (3,4,5-trihydroxy benzoic acid), a naturally occurring plant phenol, inhibited the proliferation of metastatic tumor cells, such as P815 murine mastocytoma, B16 murine melanoma and L5178 murine lymphoma cells at IC50s of 6.5, 8.0 and 3.6 microg/ml, respectively. P815 mastocytoma cells are known to metastasize specifically to the liver. When DBA/2 mice, injected intravenously with P815 cells, were treated with gallic acid at a concentration of 50 mg/kg, the number of nodules in the liver and serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), which had increased as liver metastasis progressed, decreased. However, gallic acid itself did not show a liver protective effect though the life span of DBA/2 mice was extended by gallic acid treatment. These results suggest that gallic acid is able to inhibit liver metastasis, by killing P815 cells metastasized to the liver.

Animals↗
PubMedDate not supplied

Immunohistochemical evidence for RNA virus related components in human breast cancer.

The localization of antigenic components with cross-reactivity to a 52,000 dalton group specific glycoprotein (gp52) of the mouse mammary tumor virus (MMTV) in paraffin sections of human breast carcinomas is described using an indirect immunoperoxidase method. This method was first optimized on paraffin sections of mouse mammary tumors. The specificity of the reaction observed in the human tissues was established by absorption of the specific IgG with: a) purified gp52; b) several relevant and irrelevant viral preparations; c) normal human plasma, leukocytes, breast tissue, milk, actin, collagen, and hyaluronic acid; d) sheep erythrocytes, bovine mucin and fetal calf serum. Only MMTV and purified gp52 eliminated the immunohistochemical reaction in human breast tumors. Positive reactions were seen in 171 of 376 (45.5 percent) randomly selected breast carcinomas of various histopathologic types, while negative reactions were obtained in all 137 normal and benign cases tested. In those invasive tumors with an intraductal component, a higher percentage (63.9 percent) of positive cases was seen. A positive reaction of different specificity was observed in foci of apocrine metaplasia. With one exception, 99 carcinomas from 13 organs other than breast and eight cystosarcomas were negative.

Animals↗
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Secondary malignant fibrous histiocytoma following radiation therapy for carcinoma of the uterine cervix: report of two cases.

Two cases of secondary malignant fibrous histiocytoma (MFH) following radiation therapy for uterine cervical cancer are reported. The first case, a 48-year-old woman with a stage IB squamous cell carcinoma of the uterine cervix, underwent a radical hysterectomy with pelvic lymphadenectomy and postoperative radiation therapy. Five years later, she had a poorly differentiated MFH that originated in the right gluteal muscle and lung metastases. The right gluteal tumor and lung metastases were treated with radiation therapy and two courses of cisplatin and etoposide-based chemotherapy. One year after treatment the patient died of multiple pulmonary metastases, although there was no evidence of recurrence in the irradiated field. The second case, a 39-year-old woman with a stage IIB squamous cell carcinoma of the uterine cervix underwent radiation therapy alone. Eighteen years later, well differentiated MFH occurred in the right gluteal muscle with pain on elevation. External radiation therapy was performed because the tumor invaded widely to the right gluteal muscle and pelvic bone. Although the right gluteal pain improved, the tumor showed poor response to radiation. Ten months after treatment, the patient died of multiple pulmonary metastases. These two cases of postirradiation MFH demonstrated different responses to radiation.

Adult↗
PubMedDate not supplied

In vitro and in vivo heat dissipation of an electrohydraulic totally implantable artificial heart.

The authors evaluated the heat transfer characteristics of an electrohydraulic totally implantable artificial heart (EH-TAH) developed at our institute. In three in vitro experiments, the heat dissipation of the EH-TAH was investigated. First, the EH-TAH was connected to a closed mock circuit filled with 1 L of saline, and driven at an input power of 20 W. The estimated heat conducted to the blood was approximately 10.3 W, which was almost half of the input power. Second, we simulated heat transfer with the circulation of a calf by using a heat exchanger. The amount of heat dissipating directly from the EH-TAH surface was calculated to be 10 W. Third, the temperature of the actuator examined with thermography was found to be almost uniform, and no prominent high temperature area was observed. In an in vivo study, the EH-TAH was implanted for 10 days in a calf weighing 62 kg. The input power was 18 +/- 2 W, the temperature of the actuator-tissue contacting surface was 39.4 +/- 0.8 degrees C, and that of the pump blood chamber was 39.8 +/- 0.4 degrees C. This slight temperature elevation was thought to be attributable to heat dissipation to the blood. On histologic study of the chest wall and the lung in contact with the actuator, vascularized connective tissue envelopes were observed, but unfavorable side effects, such as tissue necrosis, were not observed. These results suggest that the thermal effect of this system is acceptable at the input power used.

Animals↗
PubMedDate not supplied

In vitro and in vivo evaluation of a left-right balancing capacity of an interatrial shunt in an electrohydraulic total artificial heart system.

The authors evaluated the basic performance of an interatrial shunt (IAS) made by punching a hole in the atrial septum, in accommodating the left-right imbalance in our electrohydraulic total artificial heart (EHTAH) system. In an in vitro study conducted in a closed mock circuit connected with the EHTAH, the interatrial pressure gradient changed in compliance with the amount of bronchial flow and the size of the IAS. The IAS of 4.4 mm diameter or larger maintained the interatrial pressure gradient within physiologically permissible limits when the amount of bronchial flow was 5% of cardiac output or less. A left-to-right one-way valve made of a piece of pericardium, a possible option in this IAS method, successfully prevented right-to-left reverse shunt flow through the IAS. In a chronic in vivo study using a calf implanted with the EHTAH for 10 days, a 4.5 mm IAS without the one-way valve demonstrated satisfactory dynamic left-right balancing capacity with a stable interatrial pressure gradient of 4 +/- 1 mmHg over a wide range of atrial pressures. No thrombus was found in or around the IAS at autopsy. The authors conclude that the IAS is a simple and promising means of left-right balancing in the EHTAH system.

Animals↗
PubMedDate not supplied

Early changes in circulating blood volume and volume regulating humoral factors after implantation of an electrohydraulic total artificial heart.

The early changes in circulating blood volume (CBV) and volume regulating humoral factors after implantation of an electrohydraulic total artificial heart (EH-TAH) were investigated in a calf and compared with results in a sham operated control calf. CBV was measured by the dye dilution method using indocyanine green. CBV and humoral factors were periodically investigated. In the EH-TAH implanted calf, the cardiac output was estimated at 6-7 L/ min (94-109 ml/kg/min), and the aortic pressure and aerobic metabolic condition were favorable. Nevertheless, the CBV was increased to 132 and 168% of the pre-operative value (range in the control calf, 83-103%) on post operative days 4 and 8, respectively. The atrial natriuretic peptide level on days 2, 5, and 7 was 23, 170, and 240 (in the control calf, 19-61) pg/ml, respectively, and the antidiuretic hormone level was 7.3, 2.0, and 1.3 (0.5-1.3) pg/ ml, respectively. The plasma renin activity was 3.2, 3.7, and 3.1 (0.5-0.3) ng/ml/hr, respectively. The angiotensin-I and angiotensin-II levels were also increased in the EH-TAH implanted calf. It is concluded that significant water retention occurs even at sufficient cardiac output early after EH-TAH implantation. The changes in humoral factors are suggested to arise secondary to the increased CBV or other unknown factors.

Angiotensin I↗
PubMedDate not supplied

Characteristics of mixed venous oxygen saturation and physical activity as parameters for artificial heart control.

Mixed venous oxygen saturation (SvO2) and physical activity (PhyAc) are practical candidates as parameters of total artificial heart (TAH) control because SvO2 can be measured through a transparent blood pump housing with infrared rays and PhyAc can be calculated from signals of an accelerometer used for rate response pacemakers. Although the methods for measurement of the parameters have already been developed, characteristics of these parameters for TAH control, such as during exercise, are still unclear and were examined in this study. SvO2, cardiac output (CO), and PhyAc were measured as parameters. Multi-stage treadmill exercise tests were performed. Difference values (DVs) from the value at the start of exercise showed better correlation than did absolute values. Correlation coefficients between DV in CO and DV in SvO2 and between DV in CO and PhyAc were high at -0.82 and 0.72, while the time constants for the change of SvO2 and CO to the PhyAc change were 26 and 32 sec. Although the correlation coefficient between the CO and SvO2 was higher than that between CO and PhyAc, PhyAc responded more quickly to the speed change compared with the response of SvO2 and CO. It was concluded that SvO2 and PhyAc were useful parameters with different characteristics for TAH control during exercise.

Animals↗
PubMedDate not supplied

Apoptosis induced by heavy ion (carbon) irradiation of two human tumours with different radiosensitivities in vivo: relative biological effectiveness (RBE) of carbon beam.

The effect of heavy ion (carbon beam) on apoptosis in vivo was studied. The human brain tumors xenografts of different radiosensitivities were used. The results demonstrated that the effect of carbon beam on apoptosis was similar to photon in radiosensitive tumors; however, carbon beam had the advantage on apoptosis in radioresistant tumors. In ependymoblastoma, a radiosensitive tumor, the incidence of apoptosis induced by photon and by carbon at 6 hours after irradiation were 34.5 +/- 7.85% and 32.5 +/- 7.04%, respectively. In glioblastoma (radioresistant tumor), the incidence of apoptosis induced by photon and by carbon at 6 hours after irradiation were 1.35 +/- 1.68% and 4.4 +/- 2.47%, respectively. Therefore, the incidence of apoptosis was increased more than 3-fold (RBE 3.0) at 6 hours after irradiation in glioblastoma. The heavy ion (carbon) beam is effective in radioresistant tumors in vivo.

Animals↗
PubMedDate not supplied

The prognostic significance of immunohistochemically detected p53 protein expression in non-small cell lung cancer treated with radiation therapy.

The prognostic significance of nuclear p53 protein expression in survival and local control was investigated immunohistochemically in 36 patients with inoperable or unresectable non-small cell lung cancer who were treated with radiation therapy (RT). Formalin-fixed, paraffin-embedded sections obtained by bronchoscopy were used to examine the expression of nuclear p53 protein with immunohistochemistry. In 25 cases (69%), p53 protein expression was detected. There was no relation between p53 expression and other pretreatment characteristics. Response to RT was found in all p-53 negative cases versus 72% in p53-positive cases (p < 0.05). The 2-year survival rate for p53-negative cases was 51% with a median survival time of 21 months. The corresponding rate for p53-positive cases was 31% with a median survival time of 9 months. This difference, however, did not reach a statistically significant level because of the small sample size. In conclusion, the results of this study suggest that p53 protein expression may be of predictive value on response to RT in non-small cell lung cancer.

Adult↗