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Biomedical subjects

Y Mishima

Publications and source records attributed to Y Mishima.

432 records · Page 24Linked to original sources
PubMedDate not supplied

RBEs of thermal neutron capture therapy and 10B(n, alpha)7 Li reaction on melanoma-bearing hamsters.

Using Greene's melanoma transplanted into Syrian (golden) hamsters, we determined the relative biological effectiveness (RBE) of thermal neutron capture therapy (TNCT) using 10B-paraboronophenylalanine (10B-BPA) in comparison with a 9-MeV electron beam. We also obtained the RBE of the 10B(n, alpha)7 Li reaction by calculation based on summed dose data from TNCT. Throughout this study, the Kyoto University Research Reactor was used as the source for thermal neutrons; the reactor was specially altered to attain a low contamination level both for gamma-rays and fast neutrons. 10B-BPA was administered 8 hours before thermal neutron irradiation to the hamsters with melanoma. The tumor was then irradiated at 5 MW for 90 minutes. The absorbed dose from this TNCT was calculated by the method of Fairchild and Goodman (Phys. Med. Biol. 1966; 2:15-30). The RBEs of the TNCT and the 10B(n, alpha)7 Li reaction obtained by the tumor growth delay time (TGDT) method were 2.22 and 2.51, respectively, at 10.5 days of TGDT. These RBE values varied with TGDT and the absorbed dose. The RBE value of TNCT had a peak at 7.0 days of TGDT; that of the 10B(n, alpha)7Li reaction was higher at a low absorbed dose level and lower at a high absorbed dose level.

Animals↗
PubMedDate not supplied

Estimation of absorbed dose in the covering skin of human melanoma treated by neutron capture therapy.

A patient with malignant melanoma was treated by thermal neutron capture therapy using 10B-paraboronophenylalanine. The compound was injected subcutaneously into ten locations in the tumor-surrounding skin, and the patient was then irradiated with thermal neutrons from the Musashi Reactor at reactor power of 100 KW and neutron flux of 1.2 X 10(9) n/cm2/s. Total absorbed dose to the skin was 11.7-12.5 Gy in the radiation field. The dose equivalents of these doses were estimated as 21.5 and 24.4 Sv, respectively. Early skin reaction after irradiation was checked from day 1 to day 60. The maximum and mean skin scores were 2.0 and 1.5, respectively, and the therapy was safely completed as far as skin reaction was concerned. Some factors influencing the absorbed dose and dose equivalent to the skin are discussed.

Aged↗
PubMedDate not supplied

Biochemical analysis of metastasis-related Ax actin in B16 mouse melanoma cells after chemical reversional modulation and of tumor progression-related A' actin in the ontogeny of human malignant melanoma.

To examine the correlation between tumor metastasis and Ax actin in mouse melanoma and between tumor progression and A'.actin in human melanoma and further to investigate whether or not it is a generally existing principle, we studied the effects of reversion agents, which distinctly decrease metastatic ability of melanoma cells, on the appearance of Ax actin. Will an induced decrease in metastasis of established highly metastatic B16-F10 mouse melanoma cells cause the appearance of Ax actin? We also examined the appearance of A' actin in eight human benign pigment cell tumors and nine human malignant melanoma tissues or cells in relation to tumor progression. In vitro treatment of B16-F10 cells with each of these agents suppressed metastatic ability of the cells injected intravenously into syngenic mice; however, none of the treated cells represented Ax actin in vitro. These results suggest that the appearance of Ax actin may be a result of long-term tumor cell progression leading to changes in gene level, but because the treatments with these agents were only carried out over a short period, they could not effect changes in gene level; thus, Ax actin appearance remained unchanged. Appearance of A' actin was detected only in human benign pigment cell tumors such as nevus cell nevi, but not in malignant melanomas, which were also formed in a long period of tumor progression in vivo. These results suggest that A' actin is a clinically useful marker to determine the prognosis and level of tumor progression of human pigment cell tumors.

Actins↗
PubMedDate not supplied

Congenital and non-congenital depigmentation.

The hypofunction of melanocytes results in congenital and noncongenital depigmentation. Congenital depigmentation can be further divided into two groups; the first is depigmentation caused by loss of melanization in premelanosomes represented by oculocutaneous albinism; the second group is congenital decrease of melanocytes represented by nevus dipigmentosus. In contrast, acquired progressive depigmentation represented by vitiligo vulgaris and Sutton's leukoderma is characterized by the loss of premelanosome synthesis. The pathogenesis of these three major types of melanogenic defects has been further discussed with the current clinical, biological and immunological view of melanogenesis.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Biliary carcinoembryonic antigen levels can predict metachronous liver metastasis of colorectal cancer.

We set out to determine whether carcinoembryonic antigen (CEA) levels in gallbladder bile and serum can predict metachronous liver metastasis of colorectal cancer. At the time of surgery, gallbladder bile and serum were sampled for enzyme immunoassays of CEA. Upper limit (mean +/- 2SD) of the normal range for CEA in bile was established from samples at surgery for nonneoplastic gallbladder disease. In 11 patients with synchronous liver metastases, biliary CEA levels correlated with the size of hepatic lesions. In 49 patients without evident liver metastases at the time of surgery, elevated biliary CEA levels predicted subsequent emergence of metachronous liver metastases with 75% sensitivity, 85% specificity, and 84% accuracy; serum CEA levels were not a reliable predictor. In conclusion, determination of biliary CEA level at the time of colorectal resection shows promise as a way to identify patients at high risk for hepatic recurrence.

Adenocarcinoma↗
PubMedDate not supplied

Arterial insufficiency of the upper extremity with special reference to Takayasu's arteritis and Buerger's disease.

The occlusive arterial lesions of the upper extremity in Takayasu's arteritis is estimated in 72.3% in the left and in 45.6% in the right subclavian arteries, respectively. Buerger's disease also involves the arteries distal to the elbow and the digital arteries in about 22% of total cases. In Takayasu's arteritis, the surgical treatment for the upper extremity ischemia is rarely indicated, except for the cases with aneurysm, because the occlusive lesion involves exclusively the aorta and its branches, and severe ischemia of the upper digital arteries in Buerger's disease frequently causes severe ischemic symptoms of hand and fingers, such as rest pain, trophic changes and tissue loss. Therefore, the surgical treatment, including upper thoracic sympathectomy and amputation, is mandatory in some cases.

Adult↗
PubMedDate not supplied

Cranberry juice and its impact on peri-stomal skin conditions for urostomy patients.

In urostomy patients, peristomal skin problems are common and may stem from alkaline urine. Cranberry juice appears to acidify urine and has bacteriostatic properties, and is widely recommended for the reduction of urinary tract infections. Therefore, it is hypothesized that drinking cranberry juice might also prevent and/or improve skin complications for urostomy patients. To test this hypothesis, pH measurements of the skin around the stoma and of the urine of 13 urostomy patients were taken before and after instituting a regimen of drinking 160 to 320 g of cranberry juice each day for an average period of six months. Results showed an improvement in skin condition from 6 patients with erythema, maceration or pseudoepithelial hyperplasia at the beginning of the study to 2 patients with maceration or PEH. The average pH of the urine taken from the patients' pouches decreased a statistically significant amount from 8.0 to 7.3 (p = 0.0277), yet unexpectantly, the average pH of the fresh urine increased a statistically significant amount from 5.8 to 6.2 (p = 0.0178). Other results were not statistically significant. The authors conclude that while drinking cranberry juice did not appear to acidify the urine as expected, improvements were still seen in the skin conditions of the study participants, suggesting that drinking cranberry juice does positively impact the incidence of skin complications for these patients.

Aged↗
PubMedDate not supplied

Human melanoma treated by boron neutron capture therapy: comparison of the clinical response with the predicted response.

PURPOSE: A patient with malignant melanoma on the left foot was treated by thermal neutron capture therapy using 10B-paraboronophenylalanine. We compared the actual (clinical) response with the predicted response estimated using our past experimental and clinical data, and discussed some problems to be overcome in the future. MATERIALS AND METHODS: We adopted an intravenous drip infusion of the compound whereby 170 mg/kg of the drug was administered over 4-5 hours before neutron irradiation. The patient was then irradiated with thermal neutrons from the Musashi Reactor at a reactor power of 100 kW and a neutron flux of 1.0 x 10(9) n/cm2/s at the collimator surface. The total absorbed dose to the melanoma and the surrounding skin was calculated by multiplying the thermal neutron fluences by the conversion factor. RESULTS: The total absorbed doses to the melanoma and the surrounding normal skin were calculated as 19.0 and 9.4 Gy, respectively. These absorbed doses were estimated at 33.5 and 14.2 RBE-Gy, respectively, assuming that the relative biological effectiveness (RBE) of the high LET radiations was 2.0 and that each component of the mixed radiation was simply additive. The melanoma showed marked regression with mild skin reaction (dry desquamation) a month after therapy, and finally disappeared 10 months after therapy. There were no no substantial side effects. CONCLUSION: We concluded that the outcome of our calculated dose values agreed well with the clinical response and that their compatibility indicated considerable validity for our approach. However, there are still some problems-uncertainty concerning the 10B concentration in tumor and skin, determination of the total absorbed dose, and a single curative dose for malignant melanoma-to be overcome with regard to clinical use of this therapy.

Aged↗