PubMed Health⌕ Search

Biomedical subjects

M Koishi

Publications and source records attributed to M Koishi.

32 records · Page 2Linked to original sources
PubMed1985

Preparation of serum albumin microcapsules.

Simple coacervation of bovine serum albumin was studied to prepare biodegradable microcapsules. Three types of microcapsules, which differed in shape, were obtained by changing either core size or the bovine serum albumin concentrations of the coacervating systems. Mononuclear microcapsules were prepared by using spherical poly(acrylonitrile) beads as a core material.

1-Propanol↗
PubMed1984

Physicopharmaceutical characteristics of an oil-in-water emulsion-type ointment containing diclofenac sodium.

The oil-in-water (o/w) emulsion-type ointment was prepared with food additives containing diclofenac sodium. The oil phase and the emulsifier used were 1,2,3- propanetriyl trioctanoate (caprylic acid glyceryl ester) and sugar wax, and sugar ester, respectively. The emulsion stability of the o/w emulsion-type ointment as well as the diclofenac sodium release profile were investigated and compared with those from conventional ointments. The emulsion stability was evaluated in terms of the viscosity of the emulsion product, the particle size distribution of oil droplets, and the zeta potential of the droplets. It was found that sugar esters have excellent properties as emulsifiers, based on the results of viscosity and zeta potential measurements. The in vitro release test revealed that the amount of diclofenac sodium released from o/w emulsion-type ointment was greater than from the hydrophilic and absorptive ointment. Accordingly, it was concluded that o/w emulsion-type bases are suitable for pharmaceutical use in ointment products.

Chemical Phenomena↗
PubMed1984

Effects of acrylic acid polymer and its arrangement on drug release from a wax matrix.

The release of phenacetin from a wax matrix was improved by the addition of an acrylic acid polymer. Increasing the amount of polymer increased the release rate of phenacetin due to the formation of pores and channels in the matrix resulting from leaching of the polymer. The leaching was affected by the pH of the dissolution medium as well as by the methods used to prepare the granules. The polymer in ordered powder mixes behaved differently from that uniformly dispersed in a wax matrix. The drug appeared to be released by an approximate zero-order process at pH 7.5 from tablets containing the polymer.

Acrylates↗
PubMed1983

In vitro drug release from egg albumin microcapsules.

The in vitro release of phenacetin from microcapsules prepared using egg albumin as the membrane material was investigated. It was shown by scanning electron microscopy that the albumin microcapsules have nonsmooth surfaces. The amount of phenacetin released is proportional to the square root of time up to 50-70% drug release. Increases in the albumin concentration and 1-vinyl-2-pyrrolidinone polymer content in the aqueous phases used in the microcapsule preparation have an effect on matrix porosity and channel tortuosity in the matrix of albumin microcapsules. The in vitro release rate was found to decrease with increasing albumin concentration and 1-vinyl-2-pyrrolidinone polymer content in the aqueous phases. The in vitro release rate per unit area also decreased with decreasing capsule size.

Capsules↗
PubMed1981

Preparation of egg albumin microcapsules and microspheres.

Protein microspheres and microcapsules containing fine hydrophilic particles (spherical silica gel beads, iron hydrous oxidemodified nylon 12, or phenacetin) were prepared by using water-soluble egg albumin, which is heat-coagulable at 50-80 degrees. The size and size distribution of the microspheres and microcapsules formed and the microencapsulation percentage of fine particles were determined, and the factors affecting them were studied. Favorable conditions are suggested to obtain phenacetin-containing microcapsules in high yield.

Animals↗
PubMedDate not supplied

Development of intra-arterial hyperthermia using a dextran-magnetite complex.

Dextran-magnetite complex (DM) is a colloidal sol of subdomain magnetite particles (i.e. a 'magnetic fluid'). The specific absorption rate of DM in an AC magnetic field is much higher than those of multidomain ferrite particles due to its different mechanism of heat generation. We designed two DM-containing embolic materials (a DM/Lipiodol emulsion and a DM/degradable starch microsphere suspension) to heat target tissues with the use of an external AC magnetic field. In vitro experiments showed that the heat-generating capacity of DM was not reduced in these mixtures. When these materials were injected into the renal arteries of Japanese white rabbits, they both achieved embolization of the artery and selective heating of the embolized kidney by exposure to a 100 kHz AC magnetic field of approximately 15,000 A/m. Histological examination showed a homogeneous distribution of DM in the embolized kidney. These results suggest the possibility of using DM-containing embolic materials for inductive hyperthermia.

Animals↗
PubMedDate not supplied

Clinical results of thermoradiotherapy for soft tissue tumours.

Thirty-one unresectable and/or recurrent soft tissue tumours in 27 patients underwent hyperthermia in combination with radiation therapy. Locoregional hyperthermia was administered once or twice a week for 40-60 min to a total of 2-14 sessions using RF capacitive or microwave heating equipment. Radiation therapy was given 10-20 min before hyperthermia at doses of 20.8 to 70 Gy. The mean +/- SD of the maximum, average, and minimum intratumour temperatures was 44.0 +/- 2.9 degrees C, 42.3 +/- 1.6 degrees C, 40.1 +/- 1.1 degree C respectively, and that of the percentage of the intratumour points that exceeded 41 and 43 degrees C was 66.0 +/- 33.6, and 31.0 +/- 26.1 respectively. Of the 31 tumours treated, 13 (42%) showed CR (complete regression), 10 (32%) PR (> 50 and < 100% regression) and 8 (26%) NC (< 50% regression). Since intratumour low density areas on post-treatment CT scans have been demonstrated to be a useful parameter for assessing tumour response to thermoradiotherapy, the presence of low density areas was also assessed. Low density areas were classified into the following three categories according to the percent area occupied in the maximal cross-section of the tumour: type I, < 50%, type II, 50-80%; type III, > 80%. Of 20 tumours evaluable, 6 (30%) exhibited type III change, 11 (55%) type II and 3 (15%) type I. All of the type III tumours demonstrated a marked response on follow-up or histopathological examination. The major complication associated with treatment was skin ulcer in two patients. The five-year survival of the total 27 patients and 18 patients who had no distant metastases at the start of treatment was 32 and 48% respectively. These results indicate the clinical benefit of thermoradiotherapy using RF capacitive or microwave equipment for locally advanced and/or recurrent soft tissue tumours.

Adult↗
PubMedDate not supplied

Clinical experiences in the thermoradiotherapy for advanced gastric cancer.

Recurrent and/or inoperable gastric cancer has been treated by thermoradiotherapy at Kyoto University Hospital since 1983. In the present study, the efficacy of hyperthermia (using radiofrequency capacitive heating) plus radiotherapy for gastric cancer was evaluated in 21 patients with local recurrence, abdominal wall metastases, peritonitis carcinomatosis or paraaortic node metastases. The intratumour temperature was measured using a microthermocouple thermometer. The means of the maximum, average, and minimum intratumour temperature were 43.5, 42.1, and 41.1 degrees C respectively. The local tumour response was evaluated using computed tomography (CT). The local response rate (complete regression plus partial regression/all tumours) was 88.9%, which seemed to be higher than that of other reports using thermochemotherapy or radiotherapy alone. The one-year cumulative survival rate was 39.1%.

Adult↗
PubMedDate not supplied

Thermoradiotherapy of superficial and subsurface tumours: analysis of thermal parameters and tumour response.

Between 1988 and 1993, 57 superficial and subsurface tumours of various tumour type were treated with a 430-MHz microwave heating device. Mean (range) tumour depth of the 57 tumours was 3.0 (0.5-6.5) cm. Fifty-four tumours were treated with thermoradiotherapy. Total radiation dose ranged from 20 to 70 Gy with a mean of 53 Gy. For the remaining three tumours, thermochemotherapy was performed. Hyperthermia was given once a week, and a total of 207 heat sessions was administered. Our goal of hyperthermia treatment was to elevate all monitored tumour points > 41 degrees C for > 30 min. The mean (range) number of intratumoral thermometry points was 3.7 (2-6). The goal of hyperthermia treatment was achieved in 49% of the sessions. At the time of maximum tumour regression, complete response was noted in 53% of the tumours treated with thermoradiotherapy. Univariate analysis demonstrated that parameters including tumour type (breast cancer versus others), tumour depth, minimum tumour temperature, average tumour temperature, minimum equivalent time at 43 degrees C, and number of heat sessions achieving the treatment goal significantly affected the tumour response of the combined treatment, while total radiation dose and number of heat sessions were not significant factors for tumour response. Multivariate logistic analysis revealed that only tumour depth (< 3 versus > or = 3 cm) was a significant prognostic factor for tumour response (p = 0.029). Tumour type (breast cancer versus others) and a number of heat sessions achieving the treatment goal (0-1 versus 2-5) were found to be of borderline significance in the multivariate analysis (p = 0.075 and 0.097 respectively). The number of heat sessions achieving a minimum tumour temperature of > 41 degrees C for > 30 min seems a practical thermal parameter that influences tumour response. The present study indicates the importance of quality and quantity of heat session on the treatment outcome of thermoradiotherapy.

Adolescent↗