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Biomedical subjects

N Miyoshi

Publications and source records attributed to N Miyoshi.

At least 73 records · Page 4Linked to original sources
PubMed1990

Tissue culture of feline normal mammary gland.

To study the growth and morphology of feline mammary epithelial cells in vitro, normal feline mammary tissues as well as cells collected from feline milk were cultured and examined using phase-contrast microscopy and immunohistochemistry. The method employed was a modification of Hiratsuka et al., and was found to be useful for the culture of dissociated feline mammary tissue. Small polygonal cells and large spindle-shaped cells that were positively stained with anti-keratin and anti-actin antibodies formed colonies with a pavement-like structure in culture of mid-pregnant mammary gland. Cultures of involuting mammary gland were composed mainly of small spindle-shaped cells, which were negative for keratin immunostaining and thought to be fibroblasts. Myofibroblasts, which participate in feline mammary carcinogenesis, and show keratin negative, actin positive, were not encountered in the present culture system of normal mammary gland. The cells from milk formed small colonies, but did not grow to reach confluent monolayer.

Animals↗
PubMed1990

[A sensitization effect of hematoporphyrin oligomer (HpO) and caffeine for X-ray radiation of skin cancer].

Human malignant melanoma cells (G-361) were irradiated with X-ray for different irradiation times. The amount of DNA damage was much increased by the treatment of the cells with HpO before X-ray irradiation. Furthermore, it was found that the caffeine inhibited effectively the repair of the damaged DNA. Furthermore, HpO was administered before X-ray irradiation of transplantable skin tumor in C3H mice and/or caffeine+ was to be given the mouse after X-ray irradiation. The growth of the tumor irradiated with HpO and/or caffeine was more inhibited and the necrotic area was more expanded than that of the tumor irradiated X-ray only. Labeling Index utilizing bromodeoxyuridine (BrdU) in the viable area of the treated tumor decreased when HpO and/or caffeine were administered. The amount of DNA damage more increased in the tumor cells irradiated with HpO than that irradiated only. And, the repair of the damaged DNA was more delayed in the tumor cells irradiated with HpO and caffeine than that irradiated with the other treatments. In conclusion, it was considered that HpO might be a radioactive sensitizer and caffeine enhanced the inhibition of the repair of DNA damaged. We hope that the treatment of X-ray radiation with HpO and caffeine is useful for clinical treatment of human malignant tumor.

Animals↗
PubMed1990

Analysis of GFA-protein mRNA expression in developing bovine brain by in situ hybridization and northern blot hybridization.

Using bovine brains of adult and developmental stages, the time and place of the appearance of mRNA for glial fibrillary acidic protein (GFA-protein) were studied by in situ- and Northern blot-hybridization. Double-stranded cDNA labeled with [3H]dCTP or [32P]dCTP was used as the probe for this mRNA. To compare the location of GFA-protein mRNA and GFA-protein itself on serial sections. GFA-protein immunohistochemistry was used. By in situ hybridization with adult bovine brain. GFA-protein mRNA was detected in astroglia, most of which were in the white matter. The distribution of these astroglia by in situ hybridization was consistent with the findings by GFA-protein immunohistochemistry and Northern blot hybridization, indicating that each techniques were specific. Concerning fetal stages, GFA-protein mRNA could be detected in the brain of a fetal calf with a body length of 28 cm by in situ hybridization using the 32P-labeled probe, and the mRNA was localized in the subpial area and the fornix. These results indicated that glial maturation first became recognizable at least in the subpial area and the fornix in the brain of a fetal calf measuring 28 cm. In this fetal brain, GFA-protein mRNA was almost undetectable by Northern blot hybridization. This suggested that in situ hybridization was more sensitive and useful for the analysis of gene expression than Northern blot hybridization, when the target mRNA is present in only a limited area, such as in the brain.

Animals↗
PubMed1990

[Phthalocyanine: a new photosensitizer in photodynamic therapy].

Photodynamic therapy (PDT) with hematoporphyrin derivative (HpD) combined with laser irradiation has been introduced as a new promising clinical method for the treatment of various malignancies. Recently, sulphonated aluminum chloro phthalocyanine (A1PC) has attracted a great deal of attention as a new photosensitizer. Tissue concentrations and photodynamic effects of A1PC and HpD, that has been using clinically in PDT, were determined in nude mice transplanted bladder tumors. According to the tissue distribution of A1PC and HpD at various times after administration, the ratios of tumoral concentration to muscular concentration of A1PC were higher than those of HpD, and skin concentration of A1PC at 24 to 168 hrs. after administration was lower than that of HpD. These results suggest that more A1PC localizes in malignant tumor than HpD, and there is a possibility of reducing skin photosensitivity with A1PC as compared with HpD. The regression of tumor volume after PDT was higher with A1PC and laser light at 670 nm than with HpD and laser light at 630 nm.

Animals↗
PubMed1989

Comparative studies on microsomal NADPH-cytochrome P-450 reductase using a monoclonal antibody: tissue distribution, specific activity and peptide mapping.

1. In order to elucidate the molecular structure and the distribution of the enzyme in different microsomes, specific antibodies have been developed against rabbit liver NADPH-cytochrome P-450 reductase. 2. The monoclonal antibody (MAb B1) against rabbit liver reductase cross-reacted well with reductases from various animal species and those from various tissues of the rabbit. 3. NADPH-cytochrome P-450 reductase from rabbit tissues such as liver, lung, adrenal gland, kidney and polymorphonuclear leukocyte were closely related in structure and antigenic properties, in addition to having similar catalytic properties. 4. No multiple forms of the reductase in the rabbit were observed in liver nor in other tissues.

Animals↗
PubMed1989

Endocrine cell carcinoma (carcinoid) of the gallbladder.

We report two cases of endocrine cell carcinoma of the gallbladder associated with adenocarcinoma. The patients were women with numerous gallstones. Histologically, the tumors consisted of adenocarcinoma and endocrine cell carcinoma. An apparent transition was noted between the two types. Tumor cells of both the endocrine cell carcinoma and the adenocarcinoma were argyrophilic. In one case the tumor was surrounded by metaplastic mucosa; in the other case, it was surrounded by dysplastic and metaplastic mucosa. The nonneoplastic mucosae also contained argyrophil cells in varying number. These findings suggest that endocrine cell carcinoma of the gallbladder is derived from metaplastic epithelium of the gallbladder.

Adenocarcinoma↗
PubMed1989

[Combination effect of photodynamic therapy and microwave hyperthermia on experimental squamous cell carcinoma in vivo].

We investigated the time course of Hematoporphyrin oligomer (HpO) uptake to squamous cell carcinoma (SCC) transplanted into C3H mice after intraperitoneal (i.p.)-injection by measuring its fluorescence intensity. The fluorescence intensity was maximum at 83 hr after the i.p.-injection. The tumors once disappeared by the single application of photodynamic therapy (PDT) or microwave hyperthermia at 83 hr after HpO i.p.-injection. However, all the tumors treated with these single modalities recurred within 4 weeks after the treatments. Therefore, we investigated the therapeutic effect of microwave hyperthermia in combination with PDT at 83 hr after HpO i.p.-injection. As the results, the combination effect was the strongest when high-dose therapy was used as the first choice of therapy, irrespective of the orders of the treatments and no tumor regrowth occurred over 45 days after tumor disappearance.

Animals↗
PubMed1989

Multi-organ damage (MOD) induced by cancer cachexia and its pathogenesis.

The intraperitoneal implantation of the ascitic hepatoma cells, AH-130 to rats induced marked atrophy of the systemic organs within 2 weeks, resulting in the animal death. By the method of Feulgen hydrolysis curve analysis, the amount of single-stranded DNA and the degree of DNA instability were shown to be increased in these atrophic organs. In keeping pace with the progression of the cachectic multi-organ damage (MOD), the amount of lipidperoxide and the activity of superoxide dismutase (SOD) as measured by electron spin resonance (ESR) were increased in the ascites toward the end stage of chachexia. The increased lipidperoxide and SOD induction reflect the increased production of active oxygens, especially superoxide. The marked systemic organ damage induced in cancer cachexia seems to be due to DNA damage by active oxygens.

Animals↗
PubMed1989

Lectin histochemistry in rat thyroid tumours.

The thyroid tumours and background goiterous and adenomatous lesions induced in rats with diisopropanolnitrosamine (DIPN) plus methylthiouracil (MTU), and regenerative thyroid tissues after wounding were studied by lectin histochemistry. Ten weeks after cessation of the carcinogen treatments, carcinomas invading the surrounding tissues and blood vessels (13/20) and papillary micronodules (11/20) were formed in the thyroid tissues. In general, the carcinoma lesion was solitary, and the papillary micronodules were multiple in a single thyroid gland. Among the lectins tested, Maclura pomifera (MPA) and Solanum tuberosum (STA) showed specific binding with both carcinoma and papillary micronodule lesions, but not with the background goiterous and adenomatous lesions and regenerative thyroid tissues. The former both lesions showed higher labelling indices with BUdR or 3H-thymidine and poorer thyroglobulin accumulation than the latters, thereby indicating their enhanced proliferative capability and depressed potency of cyto-differentiation. The common cytological and histochemical properties of carcinoma lesions and papillary micronodules allow us to regard the latter as pre-invading carcinoma lesions. The lectins MPA and STA may be, therefore, used as the specific markers of malignancy in rat thyroid carcinogenesis.

Animals↗
PubMed1987

Purification and characterization of Vibrio vulnificus protease.

A protease was purified from a strain of Vibrio vulnificus isolated from the blood of a septicemic human. The vibrio was cultured in bacto peptone-yeast extract medium, and the protease was purified by a purification procedure including ultrafiltration of the culture supernatant with an Amicon YM 5 membrane, diethylaminoethyl-Sephacel column chromatography, Sephacryl S-200 column chromatography and fast protein liquid chromatography on Mono Q column. The protease preparation revealed homogeneity on polyacrylamide gel electrophoresis and about 30,000-fold purification was achieved, with a yield of about 30%. The isoelectric point of the purified V. vulnificus protease was about 5.80 and its molecular weight was ca. 45,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimum pH of the protease activity was 8.0. The V. vulnificus protease was inhibited by a metalloprotease inhibitor and zinc ion and/or ferrous ion were essential for its enzyme activity. No cysteine residue was detected in the V. vulnificus protease. The protease had caseinolytic, elastolytic and collagenolytic activities.

Amino Acids↗
PubMed1987

Activation of the plasma kallikrein-kinin system by Vibrio vulnificus protease.

Vibrio vulnificus protease enhanced hypodermic vascular permeability when injected into the dorsal skin of a guinea pig. Enhancement of permeability was observed within 2 min, and the permeability-enhancing reaction terminated at about 10 min postinjection. The permeability-enhancing reaction was greatly augmented by simultaneous injection of a kininase II inhibitor, whereas the reaction was inhibited by soybean trypsin inhibitor, a well-known inhibitor of plasma kallikrein. Furthermore, in vitro activation of plasma prekallikrein to kallikrein by V. vulnificus protease was observed. These results indicate that V. vulnificus protease enhances vascular permeability through activation of the plasma kallikrein-kinin system which generates bradykinin, factor in edema formation.

Animals↗
PubMed1986

Different instability of nuclear DNA at acid hydrolysis in cancerous and noncancerous cells as revealed by fluorescent staining with acridine orange.

Ehrlich cancer cells and inflammatory cells in mouse ascitic fluid were hydrolyzed and stained with acridine orange (AO). The AO hydrolysis curves for G1/G2 + M phase cancer cells and inflammatory cells were differentially determined using flow cytometry by monitoring the metachromatic red-shifted fluorescence of the fluorochrome bound to the single-stranded DNA produced by acid hydrolysis. By computer fitting of the Bateman function to the hydrolysis curves, the kinetic parameters k1 (rate constant for the production of single-stranded DNA), k2 (rate constant for the degradation of the produced single-stranded DNA), and y0 (theoretical value of the single-stranded DNA present initially) were determined. It was found that the k2 value, which reflects the degree of DNA instability, was much higher for cancer cells in both the G1 and G2 + M phases than for inflammatory cells. This finding led us to develop a method for the differential AO staining of cancer cells and non-cancerous cells utilizing the different degree of DNA instability at acid hydrolysis. AO staining after hydrolysis with 2N HCl at 30 degrees C for 8.5 min was found to be the optimal method. In the 60 cases of human malignant epithelial and nonepithelial tumors tested, all of the malignant tumor cells emitted metachromatic red fluorescence, while all of the nonmalignant tumor cells (5 cases of benign tumor) and normal cells emitted orthochromatic green fluorescence when observed with a violet excitation light under a fluorescence microscope. This new technique can be a useful tool for the screening of malignancy in exfoliative cytology and also for basic cancer research.

Acridine Orange↗
PubMed1986

Quantitative detection of DNA damage in the neuronal cells of the cerebellum and cerebrum by the analysis of Feulgen hydrolysis curves.

Touch smears of the cerebellum and cerebrum of ageing rats were fixed with methanol, hydrolyzed with 2 N HCl at various temperatures and for various periods, and stained with pararosaniline-Schiff reagent. The hydrolysis curves were determined by fluorescence cytophotometry and were computer fitted to the Bateman function to determine the kinetic parameters, the initial yield of apurinic acid or single-stranded DNA (y0), and the rate constants for depurination or denaturation (k1) and depolymerization (k2). The values for k1 (1/k1 is correlated with the degree of chromatin condensation) and k2 (which reflects the degree of DNA instability) steadily increased with age. The values for y0, which may indicate the degree of DNA denaturation or damage present before acid hydrolysis, also increased with age in both the cerebellum and cerebrum; however, this value was lower in the cerebellum until 15 weeks, with the situation being reversed after 35 weeks, the cross-over time being at about 25 weeks. The values of lnk1 and lnk2 were plotted as the function of the reciprocal of the absolute temperature (T) (Arrhenius plot) for both the cerebellum and cerebrum of 15- and 74-week-old rats, and the activation energies (E) for depurination and depolymerization were calculated from the slopes. In particular, the values of E for k2 decreased much more quickly with age and were smaller in cerebellum. In conclusion, the degree of DNA damage and DNA instability steadily increases in both the cerebellum and cerebrum of ageing rats, and this process is much faster in the cerebellum.

Aging↗
PubMed1986

Endocrine cell carcinoma of extrahepatic bile duct.

An endocrine cell carcinoma of the extrahepatic bile duct in a 79-year-old man is described. The patient had complaints of jaundice and epigastric pain due to a small tumor located at the confluence of the common hepatic duct with the cystic duct. Microscopically, the tumor showed a well differentiated tubular adenocarcinoma and was confined to the mucosa. Numerous tumor cells showed argyrophil and/or argentaffin reactions. Immunoperoxidase staining revealed that the tumor tissue contained somatostatin-, gastrin-and serotonin-immunoreactive cells. From these findings the tumor was diagnosed as endocrine cell carcinoma. Four years later he remains well without any evidence of recurrence or metastasis. The histogenesis of endocrine cells in the biliary tract is briefly discussed.

Adenocarcinoma↗