Biomedical subjects

Tadashi Sawada

Publications and source records attributed to Tadashi Sawada.

9 recordsLinked to original sources

PubMed2005

Diversity in neuroblastomas and discrimination of the risk to progress.

The clinical diversity of Neuroblastomas (NBs) was discriminated into three groups with high sensitivity and specificity to patient's outcome. The 'high risk' NB is defined with any of following conditions, MYCN amplification or unfavorable histology of International Neuroblastoma Pathological Classification (INPC) or low Ha-ras/trk A expression. The 'low risk' NB is defined with all following conditions, single copy of MYCN and INPC favorable histology and high Ha-ras/trk A expression and localized tumor. The remaining NBs were classified into 'intermediate risk' ones. According to these criteria, the diversity of the 248 mass-screening NBs was shown with variety progressive risk; 40% were classified in low risk group, 25% were in high risk group and 35% were in intermediate risk group.

Disease Progression↗

PubMed2004

Xenon suppresses nociceptive reflex in newborn rat spinal cord in vitro; comparison with nitrous oxide.

Although analgesic action of xenon has been reported, little is known about the effect of xenon at the spinal cord, which plays a crucial role in nociceptive transmission. We studied the effect of xenon on nociceptive reflex (the slow ventral root potential) and the monosynaptic reflex in neonatal rat spinal cord in vitro in comparison with nitrous oxide. Xenon (30%) and nitrous oxide (30%) were applied for 17 min through superfusing artificial cerebrospinal fluid. Xenon and nitrous oxide significantly reduced the amplitude of nociceptive reflex by approximately 70% and approximately 25%, respectively. Xenon and nitrous oxide also significantly reduced the amplitude of the monosynaptic reflex by approximately 35% and approximately 15%, respectively. These results indicate that xenon suppressed the synaptic transmission at the spinal cord, especially those of the slow ventral root potential, which reflect nociceptive transmission.

Animals↗

PubMed2004

[Fructose].

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Fructose↗

PubMed2004

[Xylitol].

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Humans↗

PubMed2004

[Mannose].

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Humans↗

PubMed2003

Regression of refractory rhabdomyosarcoma after allogeneic stem-cell transplantation.

A 17-year-old girl developed refractory rhabdomyosarcoma. An allogeneic peripheral-blood stem-cell transplant was performed after a myeloablative regimen. Although rapid disease progression had resolved transiently, after the start of high-dose chemotherapy, re-progression was apparently observed from day 14. However, delayed tumor regression occurred on day 30, shortly after the reduction of immunosuppressants. She achieved a partial remission. The second tumor regression provides suggestive clinical evidence that graft-versus-tumor effect may occur against rhabdomyosarcoma. Although further investigation is required, allogeneic stem-cell transplantation could provide a new therapeutic option for refractory rhabdomyosarcoma.

Adolescent↗

PubMed2002

Stimulation of N-methyl-D-aspartate (NMDA) receptors inhibits neuronal migration in embryonic cerebral cortex: a tissue culture study.

We performed a tissue culture study using embryonic rat brain to investigate the effect of excessive stimulation of NMDA receptors on neuronal migration in the cerebral cortex. After progenitor cells in the ventricular zone of E16 cerebral cortex explants were labeled with [(3)H]thymidine, the explants were cultured for 48 h, and distributions of labelled cells were evaluated autoradiographically. Stimulation of NMDA receptors by NMDA and ibotenate, NMDA receptor agonists added to the culture medium in separate studies, caused percentages of labeled cells to decrease significantly in the intermediate zone and increase in the ventricular zone. The results suggest that in rat cerebral cortex, agonist stimulation of NMDA receptors inhibits neuronal migration.

Animals↗

PubMed2002

Phase I study of irinotecan in pediatric patients with malignant solid tumors.

PURPOSE: To determine the dose-limiting toxicity, maximum tolerated dose, and potential efficacy of irinotecan in children with refractory malignant solid tumors. PATIENTS AND METHODS: In the present phase I clinical trial, 28 patients received irinotecan 50 to 200 mg/m2 per day by intravenous 2-hour infusion over the course of 3 days, repeated once after an interval of 25 days. Fifty-one treatment courses were administered to these patients. RESULTS: Dose-limiting toxicities were observed at the dose of 200 mg/m2 per day for 3 days. Diarrhea and hematopoietic toxicities were the dose-limiting factors, and the former required support with intravenous fluid administration. The occurrence of vomiting was variable. Decreases in clinical tumor marker levels were observed in the majority of patients who received two cycles of irinotecan 80 mg/m2 per day to 200 mg/m2 per day over the course of 3 days, and partial response was attained in four patients who received irinotecan in two cycles of 140 mg/m2 per day to 200 mg/m2 per day over the course of 3 days. Pharmacokinetic studies showed that the plasma concentration of irinotecan and its active metabolite SN-38 ranged from 93 to 2,820 ng/mL and 5.2 to 34.8 ng/mL, respectively, during 3-day infusions of irinotecan 200 mg/m2 per day. The mean clearance of irinotecan was 14.54 L/h per m2 (range 8.45-20.83 L/h per m2). CONCLUSION: The maximum tolerated dose was determined to be a dose of irinotecan between 160 mg/m2 per day and 180 mg/m2 per day administered over the course of 3 consecutive days on an inpatient basis, repeated once after 25 days off, and our results indicate that irinotecan is a promising anticancer agent that is worthy of phase II trials in pediatric solid tumors.

Adolescent↗

PubMed2002

Intensified chemotherapy increases the survival rates in patients with stage 4 neuroblastoma with MYCN amplification.

PURPOSE: Patients with high-risk neuroblastoma who have multiple copies of MYCN fare much worse than do those without MYCN amplification; however, it has not been clarified whether intensified chemotherapy with or without blood stem cell transplantation can alter the extremely poor prognosis of patients with amplified MYCN. METHODS AND RESULTS: Between 1985 and 1999, 301 patients older than age 12 months with stage 4 neuroblastoma were treated. From January 1985 to February 1991, 80 patients with stage 4 neuroblastoma with and without MYCN amplification uniformly received induction chemotherapy with regimen A(1) (cyclophosphamide 1,200 mg/m(2) and vincristine 1.5 mg/m(2) on day 1, tetra-hydropyranyl [THP]-Adriamycin 40 mg/m(2) on day 3, and cisplatin 90 mg/m(2) on day 5). Among 22 patients with MYCN amplification, nine (40.9%) achieved a complete remission and seven (31.8%) underwent stem cell transplantation. Of 58 patients without MYCN amplification, 43 (74.1%) achieved a complete remission and 14 (24.1%) underwent stem cell transplantation. The 5-year relapse-free survival rates were 23.2% for stage 4 patients with MYCN amplification and 33.3% for those without MYCN amplification (P = 0.029); the 5-year overall survival rates were 32.8% for stage 4 patients with MYCN amplification and 42.8% for those without MYCN amplification (P > 0.05). From March 1991 to June 1998, patients with stage 4 neuroblastoma who had 10 or more copies of MYCN were treated with regimen A(3) (cyclophosphamide 1,200 mg/m(2) per day on days 1 and 2, THP-Adriamycin 40 mg/m(2) on day 3, etoposide 100 mg/m(2) per day on days 1 to 5, and cisplatin 25 mg/m(2) per day on days 1 to 5); those with fewer than 10 copies of MYCN received regimen new A (cyclophosphamide 1,200 mg/m on day 1, THP-Adriamycin 40 mg/m on day 3, etoposide 100 mg/m per day on days 1 to 5, and cisplatin 90 mg/m on day 5), which is similar in intensity to regimen A. Among 88 patients with MYCN amplification, 63 (71.6%) achieved a complete remission and 63 (71.68%) underwent stem cell transplantation. Of 133 patients without MYCN amplification, 93 (69.9%) achieved a complete remission and 71 (53.4%) underwent stem cell transplantation. The 5-year relapse-free survival rates were 36.0% for stage 4 patients with MYCN amplification and 32.2% for those without MYCN amplification (P > 0.05), the 5-year overall survival rates were 34.0% for stage 4 patients with MYCN amplification and 38.9% for those without MYCN amplification (P > 0.05). The difference in relapse-free survival rates was significantly different (P = 0.003) between patients with MYCN-amplified tumor treated before (regimen A(1)) versus after 1991 (regimen A(3)). CONCLUSIONS: With the use of the more intensive induction regimen A plus blood stem cell transplantation for MYCN-amplified patients, survival curves for those with or without MYCN amplification now appear similar. Higher doses of chemotherapy may ameliorate the effect of MYCN amplification in patients with high-risk neuroblastoma.

Antineoplastic Combined Chemotherapy Protocols↗