Biomedical subjects

M Sasaoka

Publications and source records attributed to M Sasaoka.

At least 19 recordsLinked to original sources

PubMed2005

Optic disc topographic parameters measured in the normal cynomolgus monkey by confocal scanning laser tomography.

AIM: To study optic disc topographic parameters in normal cynomolgus monkeys by Heidelberg retina tomograph (HRT). METHODS: 12 optic disc topographic parameters were investigated in 36 normal eyes in 18 male monkeys. Mean (SD) and interocular differences were obtained for each parameter from three independent measurements made during a 1 week period. Correlations among the topographic parameters were analysed, too. RESULTS: No significant differences between right and left eyes were detected for any topographic parameters. Disc area, rim area, and height variation contour showed smaller right-left differences than other parameters. The coefficients of variation for rim area, height variation contour, rim volume, mean cup depth, maximum cup depth, mean retinal nerve fibre layer (RNFL) thickness, and RNFL cross section area were less than 10% (for rim area, less than 5%). Rim area and height variation contour showed relatively weak interrelations and neither showed a correlation with disc area. CONCLUSION: For evaluating time related changes in the optic disc by HRT in monkeys, rim area and height variation contour might be useful parameters because coefficients of variation and right-left differences were lower than for other parameters and because these parameters showed weak interrelations and no correlation with disc area.

Animals↗

PubMed2001

Aichi Cancer Center 10-year experience with conservative breast treatment of early breast cancer: retrospective analysis regarding failure patterns and factors influencing local control.

PURPOSE: We analyzed the clinical results of conservative breast therapy in our institute to determine the risk factors influencing local and distant disease recurrence. METHODS AND MATERIALS: From 1989 to 1997, 301 breasts of 295 women with early breast cancer were treated with conservative surgery and adjuvant radiotherapy. There were 212 incidences of Stage I breast cancer, and 89 of Stage II. Patients were routinely treated with local resection, axillar dissection, and 46--50 Gy irradiation given in 23--25 fractions. Some also received a radiation boost to the tumor bed. RESULTS: The 5-/8-year overall survival, disease-free survival, and local control rates were 93.2/91.5%, 86.0/80.6%, and 95.1/92.5%, respectively. Using both univariate and multivariate analyses, tumor volume, estrogen receptor status, and age < 40 years were significant prognostic factors for disease-free survival. Both age < 40 years and surgical method had a strong effect on local control by uni- and multivariate analysis. Surgical margin status was a significant prognostic factor for local control at the univariate level (p < 0.0001), though it had only borderline significance at the multivariate level (p = 0.08). No patient experienced severe morbidity due to radiotherapy. CONCLUSION: The results obtained are comparable to previously reported data. Although the follow-up period was too short to draw definite conclusions about long-term outcomes, the outcome from conservative breast treatment was acceptable.

Adult↗

PubMed2001

Effects of lomerizine, a novel Ca2+ channel blocker, on the normal and endothelin-1-disturbed circulation in the optic nerve head of rabbits.

We examined the effects of lomerizine, a new diphenylmethylpiperazine Ca2+ channel blocker, on the normal circulation in the optic nerve head and long posterior ciliary artery, and on endothelin-1-induced hypoperfusion in the optic nerve head in anesthetized rabbits using a hydrogen gas clearance method and laser Doppler flowmetry. These effects were compared with those of nilvadipine and pranidipine. Lomerizine (0.1 and 0.3 mg/kg, i.v.) significantly increased tissue blood flow in the optic nerve head and the putative blood flow in the long posterior ciliary artery with smaller reduction of blood pressure (0.3 mg/kg, i.v.) and without change in heart rate. On the other hand, nilvadipine (0.003 and 0.01 mg/kg, i.v.) and pranidipine (0.003 and 0.01 mg/kg, iv.) each significantly increased blood flow and lowered blood pressure. Moreover, lomerizine (0.1 and 0.3 mg/kg, i.v.) and nilvadipine (0.01 mg/kg, i.v.), when administered 5 min before an endothelin-1 injection (10(-6) M, 100 microl), inhibited the hypoperfusion in the optic nerve head. These results suggest that lomerizine improves the ocular circulation with minimal cardiovascular side effects. Therefore, lomerizine may have clinical potential for the treatment of eye diseases associated with local circulatory disturbances, such as normal-tension glaucoma.

Animals↗

PubMed2001

Therapeutic results of alternating chemoradiotherapy for nasopharyngeal cancer using cisplatin and 5-fluorouracil: its usefulness and controversial points.

BACKGROUND: The present study was conducted to evaluate the therapeutic results of alternating chemoradiotherapy for locally advanced nasopharyngeal cancer (NPC). METHODS: The subjects consisted of six patients with stage III nasopharyngeal cancer and 26 patients with stage IV nasopharyngeal cancer. Using 6 MV photons, radiotherapy was performed at an exposure of 1.8-2.0 Gy five times per week. That is, a total absorbed dose of 36-40 Gy was irradiated between the base of the skull and supraclavicular fossa. After decreasing the irradiation field, an absorbed dose of 26-30 Gy was additionally given thereafter. One course of chemotherapy consisted of the administration of 5-fluorouracil (5-FU) at a dose of 700 mg/m2/24 h for 5 days (days 1-5) and cisplatin (CDDP) at a dose of 50 mg/m2/24 h for 2 days (days 6-7) and a total of 2-3 courses of chemotherapy were performed. During the alternating chemoradiotherapy, chemotherapy was performed initially and 3-5 days after completing the chemotherapy, radiotherapy was performed for 3-4 weeks. Thereafter, chemotherapy and radiotherapy were performed alternately. RESULTS: The scheduled courses of alternating chemoradiotherapy were completed in 30 (94%) of 32 patients. Although one patient developed shock induced by metal allergy to CDDP, no severe adverse effects were noted in any other patients. In these 32 patients, the overall 5-year survival rate was 75% (95% confidence interval: 60-90%) and the progression-free survival rate was 63% (95% CI: 46-89%). CONCLUSIONS: This method of alternating chemoradiotherapy yielded higher or at least similar survival rates and lower toxicities than concurrent chemoradiotherapy and is worth trying in a multi-institutional study.

Adult↗

PubMed2001

Patterns of failure in carcinoma of the uterine cervix treated with definitive radiotherapy alone.

The purpose of this retrospective study was to evaluate the patterns of failure for the patients treated with definitive radiotherapy, and to discuss future treatment strategies for the uterine cervical cancer. From 1986 to 1995, 177 patients with stages I-III cervical cancer treated with a combination of two-axial conformal radiotherapy and radium brachytherapy were analyzed. The first treatment failures were pelvic failure in 11%, and distant metastases (DM) in 16% of the 177 patients. Paraaortic lymph nodes (PAN) were the most frequently metastatic regions (71%). In the pelvic control group, DM were in 6% of patients for stages I-II, and in 32% of patients for stage III. In the pelvic failure group, DM were in 75% of patients for stages I-II, and in 19% of patients for stage III. In stages I-II, the DM rate was significantly correlated with pelvic tumor control. However, there was no correlation in stage III. To improve survival, it is important to increase the pelvic tumor control rate for patients with stage I-II, and to increase the pelvic tumor and metastatic control rate in stage III. Additional treatments such as chemotherapy and/or PAN irradiation using conformal radiotherapy are required in stages I-II with locally bulky tumor and in stage III.

Adult↗

PubMed2001

[Two cases of squamous cell carcinoma of the anal canal treated with chemoradiotherapy].

We recently treated 2 patients with squamous cell carcinoma in the anal canal with bilateral inguinal nodal metastases using chemoradiotherapy. Chemotherapy (CT) consisted of 5-fluorouracil 700 mg/m2/day (continuous intravenously) on days 1-5 and cisplatin 50 mg/m2/day (continuous intravenously) on days 6-7. Chemotherapy was administered before the beginning of radiotherapy. In one patient, 2 cycles of CT were performed, and in the other patient 1 cycle only. The total radiation dose was 57.6 Gy to the primary lesion in each patient, and 53.6 Gy, 55.8 Gy to the nodal metastases, respectively. As a primary treatment response, CR was obtained in both patients. Acute grade 3-4 hematologic toxicities were observed in one patient. The patients have had 7 and 9 months survival without disease, and excellent function of the anal sphincter after treatment.

Aged↗

PubMed2001

Optic cup enlargement followed by reduced optic nerve head circulation after optic nerve stimulation.

PURPOSE: To investigate changes in optic nerve head (ONH) circulation, visual evoked potentials (VEPs), and ONH cupping after stimulation of the optic nerve. METHODS: Electrodes were fixed above the optic chiasma in rabbits under general anesthesia. Screw-type electrodes for VEP recording were fixed on the dura. ONH circulation, intraocular pressure (IOP), and blood pressure (BP) were measured after the passage of a current of 0.1 mA for 0.1 second (weak stimulation), 1 mA for 1 second (moderate), 5 mA for 10 seconds (strong), or 25 mA for 10 seconds (severe). Normalized blur (NB), indicative of tissue blood flow and velocity, was measured in the ONH after each stimulation, by using a laser speckle circulation analyzer. Changes in VEP and ocular fundus were also recorded. The ratio of cup area (CA) to disc area (DA) was measured before and 4 weeks after stimulation. After all experiments, the ONH was histologically examined. RESULTS: Weak stimulation increased NB in ONH for 10 minutes, whereas strong or severe stimulation significantly decreased NB for a longer time, in a dose-dependent manner. BP showed no significant change, except with severe stimulation. IOP was not significantly changed. VEP amplitude was reduced 30 minutes after strong stimulation. The CA-to-DA ratio was significantly increased 4 weeks after strong stimulation. In some rabbits, disc hemorrhage occurred, followed by enlargement of disc cupping, with slight gliosis. CONCLUSIONS: Electrical stimulation of the optic nerve changed ONH circulation and VEPs and increased disc cupping. This technique warrants further investigation as an experimental model for normal-tension glaucoma.

Animals↗

PubMed2000

A combination therapy of continuous superselective intraarterial carboplatin infusion and radiation therapy for locally advanced head and neck carcinoma. Phase I study.

BACKGROUND: To improve the treatment result for locally advanced head and neck carcinoma, the authors used a combination of radiotherapy with superselective continuous intraarterial therapy using carboplatin. The dose limiting toxicity (DLT), maximum tolerated dose (MTD), and treatment effectiveness were tested in Phase I and II protocols. PATIENTS AND METHODS. Thirty-five patients were entered into the study from August 1992 to May 1997. The target arteries were the lingual artery in 18 cases, facial artery in 5 cases, maxillary artery in 11 cases, and external carotid artery initially changing to lingual artery in 1 case. Escalating daily carboplatin doses were tested, starting from 10 mg/m(2) (total dose, 360 or 400 mg/m(2)) to 15 mg/m(2) (total dose, 405 or 450 mg/m(2)) and then 20 mg/m(2) (total dose, 460 or 500 mg/m(2)). Radiotherapy was administered using a 6-megavolt linear accelerator to a total dose of 50-60 grays. Interstitial radiotherapy boost also was used for carcinoma of the tongue. RESULTS: Excluding 3 patients who discontinued treatment, the treatment results of 32 patients were complete response in 21 cases, partial response in 10 cases, and no change in 1 case. Neutropenia was the DLT, and the MTD was 500 mg/m(2). The local control rate was 64%. CONCLUSIONS: Superselective continuous intraarterial carboplatin and concurrent radiation therapy can be delivered safely with good efficacy for locally advanced carcinomas of the tongue and base of the tongue. Surgical treatment of these diseases usually incurs severe functional loss. This current approach may be a breakthrough in these cancers.

Adult↗

PubMed2000

[Alternating chemoradiotherapy for oropharyngeal cancer].

To evaluate the usefulness of chemoradiotherapy for oropharyngeal cancer, we retrospectively analyzed disease-free survival (DFS) and acute toxicities of the patients treated with this therapy. Between 1990 and 1998, 15 patients were treated with alternating chemoradiotherapy (CRT). Chemotherapy (CT) mainly consisted of 5-fluorouracil 700 mg/m2 (i.v.) on days 1-5 and nedaplatin 100-140 mg/m2 (i.v.) on day 6. Chemotherapy was administered before the beginning of radiotherapy. One cycle of this treatment consisted of CT and a subsequent 27 to 36 Gy of radiotherapy, as a general rule, two cycles were performed. Radiotherapy was delivered in single daily fractions of 1.8 to 2 Gy, to a total dose of 54 to 75 Gy for local lesions and 45 to 86.3 Gy for nodal metastases in the neck. As a historical control, 52 patients treated with curative radiotherapy between 1971 and 1990 were analyzed and compared with the CRT group in terms of DFS. The complete response rate with CRT was 100%. The three-year DFS were 87% and 38% with CRT and RT, respectively. There was a significant difference between the two groups (p = 0.0081). The most frequent and severe acute toxicity was mucositis, with grade 3-4 occurring in 47%. Acute hematologic toxicities were mild. Therefore, this CRT is considered to be an effective and tolerable treatment, and is expected to improve survival for oropharyngeal cancer patients.

Adult↗

PubMed1999

Selective effects of lomerizine, a novel diphenylmethylpiperazine Ca2+ channel blocker, on cerebral blood flow in rats and dogs.

1. In the present study we examined the effects of a new Ca2+ channel blocker (lomerizine), an antimigraine drug, on cerebral cortical blood flow (CBF) in anaesthetized rats (laser Doppler flowmetry) and on vertebral blood flow in anaesthetized beagle dogs (electromagnetic flowmeter). 2. Lomerizine (1.25-10 mg/kg, p.o.) dose-dependently increased CBF in rats without affecting blood pressure (BP) or heart rate (HR). 3. The plasma concentration of lomerizine (free base) in anaesthetized rats at 30 and 60 min after the initial administration of 5 mg/kg, p.o., time at which there was a significant increase in CBF, was similar to that reported in healthy subjects receiving lomerizine at 10 mg (2 x 5 mg)/day, p.o., a dose that significantly reduces the frequency and mean duration of headache attacks. 4. Flunarizine (10 mg/kg, p.o.) did not increase CBF significantly. Flunarizine (20 mg/kg, p.o.) did not increase CBF, but did decrease BP 30-120 min after its administration. 5. Lomerizine (2.5 and 5 mg/kg, intraduodenally) dose-dependently increased vertebral blood flow in dogs without significantly changing BP or HR. With 10 mg/kg intraduodenal lomerazine, vertebral blood flow remained elevated from 20 to 240 min after administration and BP was decreased from 20 to 120 min. 6. Thus, lomerizine had a greater effect on CBF than on BP and HR and, therefore, it may be clinically effective in conditions associated with circulatory disturbances in the brain, such as migraine, without producing systemic effects (e.g. hypotension) generally seen with other Ca2+ channel blockers.

Animals↗

PubMed1999

[Concurrent chemoradiotherapy using protracted infusion of low-dose CDDP and 5-FU and radiotherapy for esophageal cancer].

PURPOSE: We evaluated the effects and safety of concurrent chemoradiotherapy for patients with esophageal cancer. MATERIALS AND METHODS: Between March 1994 and April 1998, concurrent chemoradiotherapy using protracted infusion of low-dose cisplatin (CDDP: 3-6 mg/m2/24h), 5-fluorouracil (5-FU: 200 mg/m2/24h) and radiotherapy was given to 26 patients. The median age was 70 yr, with a range from 58 to 86 yr. With regard to TNM classification (1987), six patients were stage II, five stage III, and 15 stage IV. Radiotherapy was performed by external irradiation alone in 23 patients and external irradiation plus brachytherapy in three patients. One patient underwent surgery after a dose of 40 Gy owing to the possibility of idiopathic bleeding from the stomach. RESULTS: Locally, primary effects resulted in complete response in 11 patients (42.3%) and partial response in 15 (57.7%). Acute toxicity was primarily hematologic. Leukopenia and thrombocytopenia of grade 3 or 4 occurred in eight (30.7%) and six (23.0%) of 26 patients, respectively. In patients administered CDDP at more than 5 mg/m2/day, hemotoxicity was severe because in five of the 10 patients administered 5 mg/m2 CDDP and one of the two patients administered 6 mg/m2 CDDP, thrombocytopenia of grade 3 or 4 occurred. CONCLUSION: Protracted infusion of low-dose CDDP and 5-FU with concomitant radiation therapy is effective, but from the point of acute toxicity, the optimal dose of CDDP and 5-FU needs further investigation.

Aged↗

PubMed1997

High dose rate endobronchial brachytherapy using a new applicator.

BACKGROUND AND PURPOSE: To obtain adequate spatial dose distribution for endobronchial brachytherapy, we applied reference dose points according to the bronchial diameter. For this purpose, we devised a new applicator of which the source transfer tube is contained in the center of the lumen for high dose rate (HDR) brachytherapy. MATERIALS AND METHODS: Thirty-nine patients with endobronchial cancer underwent endobronchial brachytherapy using an HDR afterloading machine with an Ir-192 source. In the nine patients treated with curative intent, treatment consisted of external beam radiotherapy with 40-60 Gy for 4-6 weeks and endobronchial brachytherapy with three fractions of 6 Gy. The 30 patients treated with palliative intent received one fraction of 10 Gy with or without external beam irradiation. The reference dose points were prescribed according to bronchial diameter, which was measured by the applicator's radiopaque wing expansion reflecting the bronchial caliber. RESULTS: The new applicator could be placed at the intended site in 37 lesions. Of 12 lesions which were treated with curative intent, eight (67%) disappeared after brachytherapy. The overall survival at 3 years of all patients and of the patients treated with curative intent was 22 and 64%, respectively. CONCLUSIONS: The source should be positioned in the center of the lumen; this technique is helpful in reducing side-effects caused by inhomogeneous dose distribution of endobronchial brachytherapy.

Adult↗

PubMed1997

[Radiation therapy for uterine cervix cancer: importance of evaluation of pre-treatment tumor size with MR imaging].

From May 1992 through December 1995, a total of 42 patients with previously untreated squamous cell carcinoma of the uterine cervix were treated by using middle-dose-rate intracavitary therapy, and their previously treated local tumor volume was evaluated with MRI. According to the staging of FIGO, 2 patients were classified as Stage IB, 2 as IIA, 18 as IIB, 1 as IIIA, 14 as IIIB, 2 as IVA and 3 as IVB. Cumulative 3-year survival rates were 89% in Stage IIB and 54% in IIIB. 3-year local control rates were 100% in Stage IIB and 67% in IIIB. On the other hand, the cumulative survival rate for the local control group in all stages was 100% at 2 years and 82% at 3 years. For the pelvic failure group it was 41% at 2 years. All of those in the pelvic failure group had bulky local tumor sizes of more than 60 mm in the previous treatment MRI study. The 3-year cumulative survival rate and local control rate for tumors less than 60 mm were 84% and 100%, but for tumors over 60 mm the respective rates were 45% and 33% (p < 0.01). The a results showed that the group with pretreatment of local tumors over 60 mm on MRI had a poor outcome. We concluded that pretreatment tumor volume is an important factor in prognosis and the evaluation of pretreatment tumor volume by imaging study (MRI) is necessary.

Adult↗

PubMed1995

[A case of nonarteritic anterior ischemic optic neuropathy with cilioretinal artery occlusion].

We report a case of nonarteritic anterior ischemic optic neuropathy (AION) with cilioretinal artery occlusion. The patient was a 61-year-old man with sudden visual loss in his right eye. Funduscopy showed pale swelling of the entire optic disc with retinal ischemic edema of the upper half of the retina, and fluorescein angiography revealed faint filling of the dye in the optic disc in the retinal arterial phase, and dye staining of the optic disc in the late phase. We initially diagnosed the disease as AION with branch retinal artery occlusion, but systemic administration of a corticosteroid and urokinase were ineffective and the optic disc became atrophic. As the optic disc swelling decreased and the course of arteries in the optic disc became clear, we repeated fluorescein angiography which proved that the involved upper retinal artery was a cilioretinal artery having earlier dye appearance than the lower retinal artery. Thus, we finally diagnosed the disease as AION with cilioretinal artery occlusion. We believe that Hayreh's view that AION may result from occlusion of the posterior ciliary artery is supported by the intraocular findings in this case.

Ciliary Body↗

PubMed1979