Biomedical subjects

Jun-ichi Mimaya

Publications and source records attributed to Jun-ichi Mimaya.

6 recordsLinked to original sources

PubMed2006

Irinotecan for children with relapsed solid tumors.

Irinotecan is expected to become a new drug for childhood solid tumors. Sixteen children with relapsed solid tumors received irinotecan 180 mg/m2/day for 3 consecutive days, repeated once after 25 days off. Their original tumors were neuroblastoma in 7, rhabdomyosarcoma in 3, nephroblastoma and undifferentiated sarcoma in 2 each, and primitive neuroectodermal tumor and leiomyosarcoma in 1 each. The average age at trials was 6 years. Partial response was achieved in 5 (31.3%) (neuro-blastoma, rhabdomyosarcoma, nephroblastoma, undifferentiated sarcoma, and leiomyosarcoma), and decrease in tumor marker in the other 2. Irinotecan appears promising, and could become included in the first-line treatment.

Camptothecin↗

PubMed2006

Spontaneous regression of metastases including meningeal metastasis after gross resection of primary tumor in an infant with stage 4 neuroblastoma.

Neuroblastoma is the most common extracranial solid tumor in childhood. Spontaneous regression has been well described in infants, especially in those with stage 4S and those with low-stage neuroblastoma detected by screening. However, neuroblastoma presenting with intracranial metastasis is generally considered to need a postoperative chemotherapy. Here, we report a 3-month-old girl with stage 4 neuroblastoma presenting with spontaneous regression of metastatic tumor including meningeal metastasis after gross resection of primary tumor. Further investigation may be required to detect patients of this kind without the need of postoperative chemotherapy regardless of their stage at diagnosis.

Diagnosis, Differential↗

PubMed2005

HLA-B polymorphism in Japanese HIV-1-infected long-term surviving hemophiliacs.

Approximately 30% of patients with hemophilia in Japan were infected with human immunodeficiency virus (HIV) in early 1980s through contaminated blood products. In 1995, a cohort of HIV-infected, asymptomatic patients with hemophilia was set up for follow-up study. Although the patients met the criteria for long-term non-progressor (LTNP) at the entry to the cohort, some of them later developed lymphopenia during five more years of observation. We collected blood samples from 80 long-term survivors; 42 of them did not require antiviral therapy, but the rest were under treatment. Analysis of HLA-B genotype revealed that carriers of known HIV-resistant alleles such as HLA-B*5701, B*5801, and alleles of B27 antigenic group were not increased in frequency, but that HLA-B*1507 was increased in the cohort (6.25% vs. 1.03%, OR = 6.40, p = 0.039). We also observed the decrease in carriers of HLA-B*5401 (3.75% vs. 14.95%, OR = 0.22, p = 0.016). HLAB* 5401 is a relatively common allele in East Asian populations and belongs to the same B22 antigenic group as B55 and B56 which were reported to associate with rapid progression. Our data indicated that HLA class I is one of the host factors involved in the retardation of HIV disease progression as also reported in the previous studies; however, the alleles associated with this resistance were not the same because of divergent host genetic background.

Alleles↗

PubMed2003

Neuroblastoma detected by mass screening: the Tumor Board's role in its treatment.

Japan has a nationwide mass-screening program for neuroblastoma in 6-month-old infants. Neuroblastoma can regress spontaneously, and some institutions observe selected cases. We evaluated the management of screened neuroblastoma at our hospital since 1997 when an observation program was introduced. Criteria for the observation program were stage-I, stage-II, or stage-IVs tumors, urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA) levels <40 microg/mg creatinine, tumor <5 cm in diameter, no invasion to the intraspinal canal or great vessels, and parental consent to participate. Patients who did not meet observation criteria underwent surgery or mild chemotherapy according to the location of the tumor. If patients met observation criteria after chemotherapy, surgical intervention was no longer performed. Thirty-six patients attended our hospital for screened neuroblastoma from 1997 to 2002. Thirty-three patients who were managed at our hospital participated in this study. Ten subjects met observation criteria. Tumors regressed in 7 patients (mean follow-up period 36.3 months) with corresponding decreases in VMA and HVA levels (group A). Three underwent surgery (group B) because of increasing VMA and HVA levels, increase in tumor size, or guardian's request. Twenty-three subjects did not meet observation criteria. Four patients underwent primary surgery (group C), and 19 patients had chemotherapy initially. Fourteen patients met observation criteria after chemotherapy and two are still having chemotherapy (group D). Three patients required surgery due to insufficient regression of their tumors (group E). Fourteen subjects in group D had marked decreases in VMA and HVA levels and tumor size (mean follow-up period 29.1 months), and tumors were not detected using imaging techniques in 8 patients. Histological examination of all resected specimens during the study period showed favorable histology and no N-myc amplification. There was no evidence of unfavorable prognosis in any of the 33 subjects, although 1 patient who underwent primary surgery had a vanishing kidney 1 year later and 1 patient had multiple bony metastases after complete resection of tumor, which was treated by chemotherapy. Until the real significance of mass screening for neuroblastoma as a public health measure is confirmed, observation with careful follow-up should be adopted more extensively because it has a favorable outcome in many cases, and is associated with minimal therapeutic complications.

Adrenal Gland Neoplasms↗

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

[Continuous infusion of recombinant activated factor VII during and after elbow arthroplasty in a hemophilia A patient with inhibitors].

Recombinant activated factor VII (rFVIIa) is a recently added new agent for the treatment of hemophiliacs with inhibitors. A major drawback to the use of rFVIIa is its short half-life, necessitating frequent and intermittent bolus injections. Continuous infusion of rFVIIa has been reported as a feasible, convenient, safe and cost-effective alternative to intermittent bolus injections. We report the use of continuous rFVIIa infusion during and after left elbow arthroplasty in a hemophiliac with a high titer of inhibitor to factor VIII. rFVIIa was administered as a bolus injection (100 micrograms/kg) at the start of the operation, after which continuous infusion (10-30 micrograms/kg/h) was immediately started and continued for 6 days. Tranexamic acid (50 mg/kg/day, p.o.) was also administered as an antifibrinolytic treatment. Laboratory monitoring of hemostatic efficacy was performed in this case using prothrombin time and the thrombelastogram. Finally, effective intra- and postoperative hemostasis and normal healing of the surgical incisions were achieved, except for local thrombophlebitis. Although the optimal maintenance or target level of rFVIIa has been a matter of debate, we consider continuous infusion of rFVIIa to be a feasible, convenient, safe and cost-effective alternative to intermittent bolus injections.

Antibodies↗