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T Akimoto

Publications and source records attributed to T Akimoto.

At least 73 records · Page 4Linked to original sources

Analysis of recurrence of squamous cell carcinoma of the uterine cervix after definitive radiation therapy alone: patterns of recurrence, latent periods, and prognosis.

PURPOSE: A retrospective analysis was performed with emphasis on the patterns of recurrence, latent period, and prognosis in patients with cervical squamous cell carcinoma of the uterus treated with definitive radiation therapy alone. Late recurrence, which was observed more than 5 years after the initial radiation therapy, was finally focused on and discussed. MATERIALS AND METHODS: Between 1976 and 1994, 256 patients with squamous cell carcinoma of the uterine cervix without hematogenous metastasis were treated with definitive radiation therapy alone. The patients were staged as follows according to the FIGO classification: 26 in Stage I, 56 in Stage II, 124 in Stage III, 28 in Stage IVa, and 22 in Stage IVb. All the patients were treated with external beam irradiation and low-dose-rate intracavitary brachytherapy. RESULTS: A total of 74 patients had recurrence. The recurrence appeared in 67 cases (90.5%) within 5 years. Metastasis to para-aortic and/or supraclavicular nodes developed later than other types of recurrence. Among patients with lymphogenous metastasis, there were more 5-year survivors after recurrence than with other types of recurrence. Patients with early recurrence, within 2 years of the initial therapy, had a worse prognosis than those with recurrence more than 2 years after treatment. Seven patients (2.7%) in all developed late recurrence more than 5 years after the treatment. The first site of recurrence was an abdominal para-aortic or supraclavicular node in all patients, excluding one patient who developed intrapelvic lymph node metastasis. Six patients had pelvic node metastasis detected with lymphangiography at the initial treatment. Median survival after late recurrence was 16.0 months. Two of 7 patients survived more than 3 years after secondary radiation therapy, and the remainder died of recurrent disease. CONCLUSION: Patients with para-aortic and/or supraclavicular node metastasis that developed late after the initial treatment are more likely to survive due to secondary radiation therapy. Careful follow-up is emphasized for long-term survivors.

Aged↗

Genistein, a tyrosine kinase inhibitor, enhanced radiosensitivity in human esophageal cancer cell lines in vitro: possible involvement of inhibition of survival signal transduction pathways.

PURPOSE: The effect of genistein, a tyrosine kinase inhibitor, on radiosensitivity was examined, especially focusing on "survival signal transduction pathways." METHODS AND MATERIALS: Two human esophageal squamous cell cancer cell lines, TE-1 (p53, mutant) and TE-2 (p53, wild), were used. Radiosensitivity was determined by clonogenic assay, and activation of survival signals was examined by Western blot. RESULTS: Genistein (30 microM) greatly enhanced radiosensitivity in these cell lines by suppressing radiation-induced activation of survival signals, p42/p44 extracellular signal-regulated kinase and AKT/PKB. Significant increase in the percentage of apoptotic cells and increased poly[ADP-ribose] polymerase cleavage were observed in TE-2, but not in TE-1 even after combination of genistein with irradiation. In terms of changes in expression of p53-related proteins, increase in expression of Bax and decrease in that of Bcl-2 were observed in TE-2 but not in TE-1, suggesting that the main mode of cell death induced by genistein in a cell line with wild type p53 differed from that with mutant p53. CONCLUSIONS: This study suggested that survival signals, including p42/p44 ERK and AKT/PKB, may be involved in determining radiosensitivity, and genistein would be a potent therapeutic agent that has an enhancing effect on radiation.

Apoptosis↗

Antiprothrombin autoantibodies in severe preeclampsia and abortion.

PURPOSE: We examined the levels of autoantibodies against prethrombin-1 and fragment-1 in pregnant women to determine the type of autoantibodies that were associated with severe preeclampsia or spontaneous abortion. SUBJECTS AND METHODS: We measured autoantibodies bound to prothrombin, prethrombin-1, and fragment-1 by using an enzyme-linked immunosorbent assay (ELISA) in 12 healthy nonpregnant women, 36 women with normal pregnancies, 28 pregnant women with severe preeclampsia, and 19 pregnant women who subsequently had spontaneous abortion. RESULTS: Plasma samples in 10 (36%) of the 28 women with severe preeclampsia and 11 (58%) of the 19 women with spontaneous abortion were positive for antiprothrombin antibodies as compared with 3 (9%) of the 36 women with normal pregancies. All 11 of the positive samples from women who had spontaneous abortions were positive for antiprethrombin-1 antibody, but only 1 was positive for antifragment-1 antibody. The mean (+/- SD) titer of antiprethrombin-1 antibodies in patients with spontaneous abortion (36 +/- 9 U) was higher than that in women with normal pregnancies (10 +/- 4 U; P < 0.01). Antiprethrombin-1 antibody was detected in only 2 women with severe preeclampsia, whereas all 10 women with antiprethrombin antibodies were positive for antifragment-1 antibody. The antifragment-1 antibody titer in patients with severe preeclampsia (49 +/- 15 U) was higher than in women with normal pregnancies (13 +/- 6 U, P < 0.01). CONCLUSIONS: There is a strong and specific association between various types of antiprothrombin antibodies with severe preeclampsia and spontaneous abortion.

Abortion, Spontaneous↗

High-dose radiation therapy for elderly patients with inoperable or unresectable non-small cell lung cancer.

PURPOSE: To evaluate definitive radiation therapy delivering doses in excess of 60 Gy for elderly patients aged 75 years or over with non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: The treatment results for 97 patients aged 75 years or older (mean age 78 years; elderly group) with inoperable or unresectable NSCLC were retrospectively analyzed and compared with those for 206 patients younger than 75 year old (mean age 64 years; younger group). The elderly patients were classified into two groups; 67 patients aged 75-79 years (the elderly A) and 30 patients aged 80 years or older (the elderly B). Most of all patients were treated with a total dose of 60 Gy or more in 2 Gy daily standard fractionation. RESULTS: The overall 2 and 5 year survival rates were 32 and 13% for the elderly A group, and 28 and 4% for the elderly B group, respectively, compared with 36 and 12% for the younger group. There was not a statistically significant difference in survival rates among three groups. In stage I-II NSCLC patients there was also no significant difference in survival curves among the three groups. In patients with stage III disease, however, the survival curve of the elderly B was inferior to those of the younger group and the elderly A group, although the difference was not statistically significant. After the treatment the deterioration rate of the performance status was only 5% in the younger group and 8% in the elderly group. Only three younger and two elderly patients died of late pulmonary insufficiency associated with high-dose irradiation to the proximal bronchus. No other treatment-related event was observed except for mild acceptable acute complications in the elderly groups. CONCLUSIONS: Definitive radiation therapy is recommended to the elderly aged 75 years or older with inoperable or unresectable NSCLC, especially early stage disease, as an acceptable choice of treatment.

Aged↗

The Heartmate III: design and in vivo studies of a maglev centrifugal left ventricular assist device.

A compact implantable centrifugal left ventricular assist device (LVAD) (HeartMate III) featuring a magnetically levitated impeller is under development. The goal of our ongoing work is to demonstrate feasibility, low hemolysis, and low thrombogenicity of the titanium pump in chronic bovine in vivo studies. The LVAD is based on so-called bearingless motor technology and combines pump rotor, drive, and magnetic bearing functions in a single unit. The impeller is rotated (theta z) and levitated with both active (X, Y) and passive (Z, theta x, theta y) suspension. Six prototype systems have been built featuring an implantable titanium pump (69 mm diameter, 30 mm height) with textured blood contacting surfaces and extracorporeal electronics. The pumps were implanted in 9 calves (< or = 100 kg at implant) that were anticoagulated with Coumadin (2.5 < or = INR < or = 4.0) throughout the studies. Six studies were electively terminated (at 27-61 days), 1 study was terminated after the development of severe pneumonia and lung atelectasis (at 27 days) another study was terminated after cardiac arrest (at 2 days) while a final study is ongoing (at approximately 100 days). Mean pump flows ranged from 2 to 7 L/min, except for brief periods of exercise at 6 to 9 L/min. Plasma free hemoglobin ranged from 4 to 10 mg/dl. All measured biochemical indicators of end organ function remained within normal range. The pumps have met performance requirements in all 9 implants with acceptable hemolysis and no mechanical failures.

Animals↗

The role of diastolic pump flow in centrifugal blood pump hemodynamics.

We tried to verify the hypothesis that increases in pump flow during diastole are matched by decreases in left ventricular (LV) output during systole. A calf (80 kg) was implanted with an implantable centrifugal blood pump (EVAHEART, SunMedical Technology Research Corp., Nagano, Japan) with left ventricle to aorta (LV-Ao) bypass, and parameters were recorded at different pump speeds under general anesthesia. Pump inflow and outflow pressure, arterial pressure, systemic and pulmonary blood flow, and electrocardiogram (ECG) were recorded on the computer every 5 ms. All parameters were separated into systolic and diastolic components and analyzed. The pulmonary flow was the same as the systemic flow during the study (p > 0.1). Systemic flow consisted of pump flow and LV output through the aortic valve. The ratio of systolic pump flow to pulmonary flow (51.3%) did not change significantly at variable pump speeds (p > 0.1). The other portions of the systemic flow were shared by the left ventricular output and the pump flow during diastole. When pump flow increased during diastole, there was a corresponding decrease in the LV output (Y = -1.068X + 51.462; R(insert)(2) = 0.9501). These show that pump diastolic flow may regulate expansion of the left ventricle in diastole.

Analysis of Variance↗

Erythropoietin modulates angiotensin II- or noradrenaline-induced Ca(2+) mobilization in cultured rat vascular smooth-muscle cells.

BACKGROUND: It has been reported that human recombinant erythropoietin (rHuEpo) modulates the sensitivity of the cardiovascular system to angiotensin II (Ang II) or noradrenaline (NA). In the present study, we explored the effect of rHuEpo on the responsiveness of Ang II- or NA-induced cytosolic free calcium ([Ca(2+)]i) mobilization in cultured rat vascular smooth-muscle cells (VSMC). METHODS: [Ca(2+)]i concentrations in VSMC were measured by using the calcium-sensitive fluorescent dye fura-2. RESULTS: The addition of rHuEpo (250 U/ml) alone induced elevation in [Ca(2+)]i, which remained significantly elevated above basal level for at least 60 min in the presence of extracellular Ca(2+). Pre-incubation with specific protein kinase C (PKC) inhibitor calphostin C (1 micromol/l) significantly reduced the peak and the sustained elevations of [Ca(2+)]i. Pre-treatment with rHuEpo for 60 min increased both basal [Ca(2+)]i and the changes in [Ca(2+)]i by Ang II or NA in a dose-dependent manner in the presence of extracellular Ca(2+). The synergistic effects of rHuEpo with Ang II or NA were also retained when VSMC were bathed in the Ca(2+)-free medium after the pre-incubation of rHuEpo. Conversely, they were diminished in the presence of extracellular Ca(2+) combined with intracellular Ca(2+) release inhibitor 8-(NN-diethylamino)octyl-1,3,4,5-trimethoxybenzoate (TMB-8). The synergistic effects of rHuEpo were also diminished by PKC depletion or by PKC inhibitor. CONCLUSIONS: These observations suggest that rHuEpo has synergistic effects on Ang II- or NA-induced [Ca(2+)]i mobilization, particularly on intracellular Ca(2+) release, in VSMC. This may be a potential mechanism contributing to hypertension associated with rHuEpo therapy.

Angiotensin II↗

Involvement of erythropoietin-induced cytosolic free calcium mobilization in activation of mitogen-activated protein kinase and DNA synthesis in vascular smooth muscle cells.

BACKGROUND/OBJECTIVE: Human recombinant erythropoietin (rHuEPO) induces cytosolic free calcium ([Ca2+]i) mobilization, an activation of mitogen-activated protein (MAP) kinase and DNA synthesis in several tissues. We explored the mechanism of rHuEPO-induced [Ca2+]i mobilization and its role in the activation of MAP kinase and DNA synthesis in vascular smooth muscle cells (VSMC). METHODS: [Ca2+]i concentrations were measured by fura-2. MAP kinase activation was analyzed using an immunocomplex kinase assay and Western blotting. DNA synthesis was measured as an incorporation of 5-bromo-2'-deoxyuridine. RESULTS: Although addition of rHuEPO significantly increased [Ca2+]i, either in the presence or absence of extracellular Ca2+, the peak level and sustained elevation of [Ca2+]i were significantly reduced in the absence of extracellular Ca2+. Pretreatment with genistein completely blocked the elevation of [Ca2+]i in both conditions. Calphostin C and staurosporine did not completely block the elevation of [Ca2+]i. Staurosporine reduced its peak level in a dose-dependent manner, whereas calphostin C reduced its peak level at concentrations over 1 nmol/l in the presence of extracellular Ca2+. Similar results to those with staurosporine were observed with nifedipine. In the absence of extracellular Ca2+, their dose-dependent effects disappeared even though rHuEPO increased [Ca2+]i. rHuEPO activated MAP kinase and DNA synthesis, both of which were significantly suppressed by the chelation of intracellular Ca2+. CONCLUSION: These findings suggest that rHuEPO increases [Ca2+]i by both Ca2+ influx and Ca2+ release from intracellular stores. Tyrosine phosphorylation is critical in the regulation of [Ca2+]i, but protein kinase C activation is important only in the regulation of Ca2+ influx. Dihydropyridine-sensitive L-type Ca2+ channels seem to be involved in rHuEPO-induced Ca2+ influx. In addition, increase of [Ca2+]i by rHuEPO stimulates MAP kinase activation and DNA synthesis in VSMC.

Animals↗

Biological cell survival mapping for radiofrequency intracavitary hyperthermia combined with simultaneous high dose-rate intracavitary irradiation.

We examined the best way to combine recently developed radiofrequency intracavitary hyperthermia with simultaneous high dose-rate intracavitary brachytherapy in an original experimental model. Temperature distribution was measured with an experimental phantom which was immersed in a water bath with the temperature controlled at 37 degrees C. Radiation dose distribution was calculated with a treatment-planning computer. Cell survival was measured by colony assay with HeLa-TG cells in vitro. Radiation dose response at 1 - 7 Gy and time response with hyperthermia in the range of 40 - 46 degrees C were estimated. Radiation dose-response curves in simultaneous treatment with hyperthermia for 30 min at 37 to 46 degrees C were estimated and the surviving fractions in combined treatment were plotted against temperature. For intracavitary radiation alone, cell survival rates increased with increasing distance from the source. For intracavitary hyperthermia alone, the maximum temperature was observed at a depth of 13 mm from the surface of the applicator under suitable treatment conditions. Homogeneous cell killing from the surface of the applicator to a tumor depth of 13 mm was observed under a specific treatment condition. Our experimental model is useful for evaluating the best simultaneous combined treatment.

Brachytherapy↗

Modulation of endothelin-1-induced cytosolic free calcium mobilization and mitogen-activated protein kinase activation by erythropoietin in vascular smooth muscle cells.

BACKGROUND: It has been reported that human recombinant erythropoietin (rHuEPO) modulates the sensitivity of the cardiovascular system to vasoconstrictors. We investigated whether rHuEPO has modulative effects on the endothelin-1 (ET-1)-induced elevation of cytosolic free calcium concentration ([Ca2+]i) and mitogen-activated protein (MAP) kinase activation in vascular smooth muscle cells (VSMC). METHODS: [Ca2+]i was measured by fura-2/AM, and MAP kinase activation was analyzed by Western blotting. RESULTS: Exposure of VSMC to rHuEPO prior to stimulation with ET-1 enhanced both basal and ET-1-induced elevation of [Ca2+]i in a dose-dependent manner in the presence of extracellular Ca2+. The synergistic effect was also retained in the absence of extracellular Ca2+ after exposure to rHuEPO. However, the effect was diminished in the presence of extracellular Ca2+ combined with the intracellular Ca2+ release inhibitor TMB-8, PKC inhibitor, or PKC depletion. Exposure to rHuEPO also had a synergistic effect on the activation of MAP kinase induced by ET-1; however, this effect was diminished in the presence of the Ca2+ chelator BAPTA-AM. CONCLUSION: The results suggest that rHuEPO has synergistic effects on ET-1-induced [Ca2+]i mobilization, particularly on intracellular Ca2+ release, and MAP kinase activation in VSMC.

Animals↗

[Radiation therapy for head and neck cancer].

Radiation therapy is the first choice of treatment for most of the early squamous cell carcinoma of the head and neck. Conventional radiotherapy however, contributes to the high local control rates only for carcinoma of the glottic larynx and the nasopharynx. Squamous cell carcinoma of the other sites cannot be sterilized easily only by external beam radiation therapy alone. Chemoradiotherapy, conformal three-dimensional radiotherapy and multi-daily fractionation are introduced clinically to improve local control and/or survival for radioresistant tumor. In this review, consensus report of radiation therapy for carcinoma of the larynx and pharynx, which was reached an agreement in JASTRO meeting in 1998, is introduced. The role of radiation therapy in the management of head and neck cancer in present and near future is also discussed.

Carcinoma, Squamous Cell↗

Observation of anomalous single-magnon scattering in half-metallic ferromagnets by chemical pressure control

The temperature variation of the resistivity rho and specific heat C have been measured for prototypical half-metallic ferromagnets, R0. 6Sr 0.4MnO3, by controlling the one-electron bandwidth W. We have found variations in the temperature scalings of rho from approximately T2 ( R = La, and Nd) to approximately T3 ( R = Sm), and have interpreted the T3 law in terms of the anomalous single-magnon scattering process in the half-metallic system.

Journal Article↗

Caffeine enhanced radiosensitivity of rat tumor cells with a mutant-type p53 by inducing apoptosis in a p53-independent manner.

The radiosensitizing effects of caffeine on two rat yolk sac tumor cell lines with a different p53 status were investigated. A reduction of radiation-induced G(2) arrest was caused by caffeine at a concentration of 2 mM in both cell lines. The reduction of survival was observed in a combination of radiation and 2 mM caffeine only in a lower radiation dose range, but not in a higher dose range in NMT-1 with a wild type p53. Radiosensitization of caffeine was recognized even in a higher dose range for cells with a mutant-type p53. Apoptosis, which was not prominent after irradiation alone or caffeine treatment alone, was induced by irradiation in combination with caffeine in cells with a mutant-type p53 through a p53-independent pathway.

Animals↗

Radiation therapy for elderly patient with squamous cell carcinoma of the uterine cervix.

OBJECTIVE: The purpose of this study was to profile cervical squamous cell carcinoma in elderly patients undergoing radiation therapy and to study the treatment outcome and side effects of therapy. MATERIALS AND METHODS: A retrospective analysis was carried out from the records of 380 patients with squamous cell carcinoma of the uterine cervix who had been given radiation therapy between 1970 and 1994. The patients were divided into three age groups: under 70 years (youngest group; n = 215), 70 to 79 years (intermediate group; n = 124), and 80 years or older (oldest group; n = 41). Radiation therapy was performed by a combination of external beam therapy and three brachytherapy fractions using low-dose-rate sources. RESULTS: The 5-year overall survival rates in the youngest, intermediate, and oldest groups were 58, 50, and 33%, respectively, while cause-specific survival rates were 68, 70, and 65%, respectively. For the patients with stage III, the 5-year overall survival rates in the youngest, intermediate, and oldest groups were 59, 48, and 36%, respectively, while cause-specific survival rates were 72, 70, and 70%, respectively. There was no statistical significance in the 5-year intrapelvic recurrence rates among the three groups. Grade 3 or 4 complications occurred in 6.5% of the youngest, 11.3% of the intermediate, and 7.3% of the oldest groups. CONCLUSION: Radiation therapy with external beam combined with three fractions of low-dose-rate brachytherapy proved both highly effective and safe for senior patients with cervical squamous cell carcinoma.

Adult↗

Possible contribution of titin filaments to the compliant series elastic component in horseshoe crab skeletal muscle fibers.

In horseshoe crab skeletal muscle fibers, the extension of SEC at the maximum isometric force P0 is about 6% of the slack fiber length L0 (sarcomere length, 7 microns), i.e., about 210 nm per half-sarcomere, being too large to be explained by the cross-bridge and the thin filament elasticities. Cinematographic studies of isometrically contracting myofibril bundes indicate that the highly compliant SEC mostly originates from the "elastic" thick filament misalignment in each A-band during isometric force generation. Possible contribution of the titin filaments to the "elastic" thick filament misalignment is discussed.

Animals↗

Effect of brief maximal exercise on circulating levels of interleukin-12.

Interleukin-12 (IL-12) is a cytokine that was originally identified as natural killer cell stimulatory factor. It induces the activity of T-helper 1 (Th1) cells and exhibits strong anti-tumor activity. In this study, we studied the effects of brief anaerobic maximal exercise on circulating levels of IL-12. Six healthy males [mean (SD) 25.2 (2.6) years] performed a modified Wingate test exercise (resistance 0.075 kg/kg of body mass). The exercise consisted of five bouts of maximal cycling for 10 s, with rest intervals of 50 s between them. Blood samples were taken before, immediately after, 30 min after, 60 min after and 120 min after the exercise. Plasma concentrations of IL-12 were measured using an enzyme-linked immunosorbent assay. Data were corrected for hemoglobin and hematocrit measurements. Plasma concentrations of IL-12 averaged [mean (SD)] 234.2 (40.9) pg/ml before, 305.2 (62.1) pg/ml immediately after, 202.8 (24.2) pg/ml 30 min after, 239.7 (35.1) pg/ml 60 min after, and 199.6 (49.2) pg/ml 120 min after the exercise. We showed that plasma concentrations of IL-12 increased significantly immediately after brief anaerobic maximal cycle ergometer exercise (P < 0.01).

Adult↗

Effect of incident angle of light on sensitivity and detection limit for layers of antibody with surface plasmon resonance spectroscopy.

The effect of the incident angle of light on sensitivity and the detection limit for surface-plasmon resonance spectroscopy were examined. The sensitivities and the detection limit were experimentally measured using an antibody as a modeled analyte in the incident angles of a light region of 66-76 degrees. The results showed that the sensitivity of a smaller incident angle was higher than that of a larger one. For instance, the sensitivity of a 66 degree incident angle was three times higher than that of a 76 degree incident angle. The detection limit with a 66 degree incident angle was one-tenth of that with a 76 degree incident angle. These sensitivities and detection limits were compared with those of a commercially produced surface-plasmon resonance instrument. This comparison demonstrated that a wavelength resolution of the order of less than 10(-2) nm was necessary to obtain satisfactory sensitivities and detection limits. In addition, the refractive index and thickness of the antibody layer formed on a sensor surface was proposed by experimental results and theoretical calculation.

Adsorption↗

Erythropoietin regulates vascular smooth muscle cell apoptosis by a phosphatidylinositol 3 kinase-dependent pathway.

BACKGROUND: Recent studies have shown that several cytokines could induce apoptosis in vascular smooth muscle cells (VSMCs) via the induction of nitric oxide (NO). In the present study, we explored whether human recombinant erythropoietin (rHuEPO) has a modulatory effect of apoptosis on interleukin-1beta (IL-1beta) or NO donor sodium nitroprusside (SNP)-induced apoptosis in rat cultured VSMCs. METHODS: The quantitation of apoptosis among VSMCs was assessed by nuclear morphological analysis with fluorescent DNA-binding dye Hoechst 33258. Apoptotic changes were also confirmed by the detection of DNA fragmentation. The expression of EPO receptor (EpoR), cellular protein tyrosine phosphorylation, including EpoR and Janus kinase (JAK) 2, and the association of p85 subunit of phosphatidylinositol 3 kinase (PI3-kinase) to tyrosine-phosphorylated proteins, including EpoR, were explored by using Western blotting analysis combined in part with immunoprecipitation. RESULTS: rHuEPO inhibited the apoptosis induced by IL-1beta or SNP in a dose- and time-dependent manner. The anti-apoptotic effects of rHuEPO were diminished in the presence of a tyrosine kinase (TK) inhibitor genistein or anti-EpoR antibody. After stimulation with rHuEPO, EpoR and JAK 2 were tyrosine phosphorylated, and p85 subunits were associated with EpoR. Also, rHuEPO induced phosphorylation of Akt through a PI3-kinase-dependent pathway. The phosphorylation of Akt and the anti-apoptotic effects of rHuEPO were diminished in the presence of a PI3-kinase inhibitor, wortmannin. CONCLUSION: Our present study demonstrates that rHuEPO inhibites IL-1beta or SNP-induced VSMC apoptosis. The TK-dependent pathway, particularly the PI3-kinase-dependent pathway, seems to be critical to the countervailing effect of rHuEPO on IL-1beta and SNP-induced VSMC apoptosis.

Anemia↗