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Biomedical subjects

Y Zaizen

Publications and source records attributed to Y Zaizen.

26 records · Page 2Linked to original sources
PubMed1991

Different genomic and metabolic patterns between mass screening-positive and mass screening-negative later-presenting neuroblastomas.

The mass screening of neuroblastoma has been undertaken in Japan by measuring urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA) in all infants at the age of 6 months. This program may not only improve the prognosis but also provide important insights into the biology and evolution of human neuroblastoma. The authors studied and discuss the clinical significance of the N-myc oncogene, catecholamine metabolism, and other tumor markers in 43 patients with neuroblastoma who underwent the urinary screening test at 6 months of age. Thirty patients were found by the screening, and 13 were negative at the screening but later had a tumor. In the former group, the tumors were mostly in early stages (Stage I, 12; Stage II, 11; Stage III, seven), no amplification of N-myc was observed, and all patients are alive without disease. Although two patients whose urine at the screening showed elevated VMA and HVA levels and accidentally were not treated for 13 and 17 months, there was no change in the values of VMA and HVA during that time. However, in the latter group, the tumors were mostly in advanced stages (Stage I, one; Stage III, four; Stage IV, eight) and N-myc amplification was observed in seven of 13. Only two of these 13 are alive without disease. The age at diagnosis of the screening-negative group was 23 months compared with 8 months in the patients identified by screening, and the pattern of catecholamine metabolites in the screening-negative group tended to be dopaminergic with a low VMA-HVA ratio, especially in cases with N-myc amplification. These data suggest that the screening-positive patients with neuroblastoma may have favorable characteristics, and the biology of these tumors may be different from that of screening-negative later-presenting tumors. They also suggest that there may be at least two distinct subsets of neuroblastoma. For the early detection of the poor prognostic neuroblastomas, the measurement of urinary dopamine with VMA and HVA at later ages, such as 1 to 2 years, should be considered.

Adrenal Gland Neoplasms↗
PubMed1990

Stimulation of wound bursting strength during protein malnutrition.

Nutrition is one of the most important factors affecting wound healing. Patients who have significant protein malnutrition and require emergency surgery are frequently encountered. Conventional nutritional preparation for surgery, with intravenous hyperalimentation, requires 10 to 14 days to demonstrate advantageous reversal of catabolism. Growth hormone is known to have an anabolic effect in malnourished animals. The purpose of this investigation was to study the ability of growth hormone, administered from the time of celiotomy, to improve wound strength in protein-malnourished animals and compare its efficacy with preoperative nutritional repletion. Rats were divided into four groups: Group I--normal control rats, group II--malnourished rats, group III--malnourished rats treated with growth hormone for 5 postoperative days, and group IV--malnourished rats refed normal chow for 3 days before operation. Controlled laparotomy wounds were closed with monofilament nylon which was removed at the time wound bursting strength was tested. Bursting strengths at the sixth day postoperative were as follows (means +/- SD): (table; see text) Wound strength of malnourished animals was significantly less than that of controls, (P less than 0.001). Wound bursting strength of groups III and IV was significantly improved over that of malnourished animals (group II), P less than 0.001. The bursting strength of group IV was significantly higher than that of group III. Growth hormone administration following celiotomy is nearly as effective in improving wound healing as preoperative nutritional repletion. These results suggest that growth hormone may be clinically applicable in preventing wound complications in malnourished patients requiring urgent or emergency laparotomy.

Abdomen↗
PubMed1990

The effect of perioperative exogenous growth hormone on wound bursting strength in normal and malnourished rats.

Patients with significant malnutrition secondary to underlying disease may require major surgical intervention on an urgent basis. Nutritional restoration using enteral or intravenous alimentation requires a delay of 10 to 14 days and is frequently not practical. With the availability of human growth hormone (GH) produced by recombinant DNA technology, this study was undertaken to evaluate the effect of exogenous GH on wound tensile strength in a rat model. Fifty-four animals were divided into three groups: group I, normal nourished control; group II, malnourished; group III, malnourished, rat GH treated (1 mg GH administered 3 days preoperative and 5 days postoperative celiotomy). Wound tensile strength was measured at 6 days postoperatively. Wound strengths in malnourished rats were significantly less than in normal controls (P less than .001). With the administration of growth hormone in group III, wound strength was significantly improved when slightly improved over normally nourished controls (P less than .05). A dose response curve demonstrated progressive improvement in wound tensile strength from 0.01 mg/d to 1.0 mg/d. Thus growth hormone administration to malnourished animals significantly enhances wound strength. With the availability of recombinant produced human GH these observations may be clinically applicable.

Abdominal Injuries↗
PubMed1986

Patterns of destruction of mouse neuroblastoma cells by extracellular hydrogen peroxide formed by 6-hydroxydopamine and ascorbate.

The patterns of the cytolytic effects of 6-hydroxydopamine (6-OHDA), with/without ascorbate, on C-1300 and three other cloned mouse neuroblastoma cell lines (N1E-115, NS-20, N-18) were studied in vitro. The sensitivity to 6-OHDA differed and the three cloned cell lines were more sensitive than the wild type C-1300 cell line. Ascorbate synergistically potentiated the cytolytic effect of 6-OHDA to all four cell lines. The 6-OHDA cytotoxicity was eliminated by the addition of exogenous catalase but not by addition of other oxygen free radical scavengers, thereby suggesting that the hydrogen peroxide formed might influence the cells, extracellularly. In addition, the critical time for tumor cell lysis was the first 60 min of the reaction. The cytotoxicity induced by the unmasked cyclophosphamide, 4-hydroperoxycyclophosphamide, was synergistically enhanced in the presence of a nontoxic concentration of 6-OHDA and ascorbate. These data suggest that reactive oxygen intermediates may prove to be a good tool for destroying neuroblastoma cells.

Animals↗
PubMed1985

Combined treatment with cisplatin and radiation therapy for mouse Cl 300 neuroblastoma.

The efficacy of the combined treatment of cisplatin and radiation therapy for mouse C1 300 neuroblastoma was studied. Intraperitoneal cisplatin injections and/or radiation were given from 7 to 21 days after inoculation of the tumor cells into the thigh region of A/Jax mice. The combination of 15 Gy radiation and 6 mg/kg cisplatin had an additive effect on both tumour growth delay and survival rate, while that of 30 Gy radiation and 6 mg/kg cisplatin had a synergistic effect. The efficacy of the combined therapy was dependent on the dose of radiation but not on the dose of cisplatin. The normal skin of the mouse was damaged in the similar pattern with both treatments. Thus, cisplatin has a potent radiosensitising effect in the treatment of mouse neuroblastoma.

Animals↗
PubMedDate not supplied

A new analytical method for the detection of anti-tumor promoters using flow cytometry.

Flow cytometry analysis was applied to the measurement of Epstein-Barr virus (EBV) induction which is used as a short term assay for anti-tumor promoters. The data obtained by measurement with flow cytometry were parallel with those of the fluorescence microscopic method. Flow cytometry is rapid, quantitative and should be applicable for the EBV activating test.

Anticarcinogenic Agents↗
PubMedDate not supplied

Antitumor effects of soybean hypocotyls and soybeans on the mammary tumor induction by N-methyl-n-nitrosourea in F344 rats.

BACKGROUND: Soybeans are reported to have cancer inhibitory effects, probably due to their isoflavones. Soybean hypocotyls are embryo buds of soybeans and contain a higher amount of isoflavones and other factors than soybeans themselves. MATERIALS AND METHODS: The effects of soybean protein and soybean hypocotyls as diets on the development of N-methyl-n-nitrosourea (MNU) induced tumors were examined in female F344 rats. For this trial, 120 animals were used and at 6 weeks of age, groups of 30 animals were fed diets containing casein, soy protein isolate (SPI), 1.5% soybean hypocotyls and 5% soybean hypocotyls. Three weeks later all the animals except the control animals received a first dose (37.5 mg/kg body weight) of MNU by tail vein injection. At 29 weeks of age the animals received a second MNU dose (50 mg/kg body weight). Testing was performed 42 weeks after the first MNU dose. RESULTS: Analysis of cumulative palpable tumor incidence indicated that final tumor development of the SPI diet group and the hypocotyl diet groups was less than that of the casein diet group. Tumors were detected in one or more sites from 9 out of 24 rats in the casein diet group, 5 of 20 rats in SPI diet group, 6 out of 24 rats in the 1.5% hypocotyl diet group and 6 out of 23 rats in the 5% hypocotyl diet group. Pairwise comparisons indicated that the formation of tumors during the experiment was significantly less rapid in the SPI diet group and the hypocotyl diet groups than the casein group. No difference in tumor promotion was observed between the SPI diet group and the soybean hypocotyl diet groups. CONCLUSION: Our results suggest that dietary soybeans and soybean hypocotyls are capable of suppressing tumor promotion.

Animals↗