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Biomedical subjects

S Kurata

Publications and source records attributed to S Kurata.

At least 145 records · Page 8Linked to original sources
PubMed1989

Side gland of Suncus murinus as a new model of sebaceous gland: 5 alpha-reductase, androgen receptor, and nuclear androgen content in male and female animals.

The side gland of Suncus murinus is composed of well-developed sebaceous glands in both males and females. We measured the 5 alpha-reductase activity, androgen receptor content, and the intranuclear concentrations of testosterone and dihydrotestosterone in this side gland taking it as a new experimental model of human sebaceous glands. Lineweaver-Burk plot analysis suggested the presence of two classes of 5 alpha-reductase with different Km for testosterone in the homogenate. The enzyme activity was slightly higher in males than in females in the presence of a high concentration of testosterone. The levels of androgen receptors were approximately 40 and 30 fmol/mg protein in the cytosol and nuclei, respectively. The values did not differ significantly between males and females. The intranuclear concentration of dihydrotestosterone in the side gland was higher than that of testosterone in each sex. The intranuclear level of each of these two androgens in the female side gland was comparable to that in the male side gland despite the fact that the serum level of testosterone was much lower in the female. These data clearly indicate that the side gland is a typical target tissue for androgens in the female as well as in the male. Androgens other than testosterone may serve as precursors of dihydrotestosterone in the female side gland.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1989

Mongolian spots associated with cleft lip.

Of the present series comprising 66 newborns with cleft lip, 13 (20%) had pigmented macules in the labial skin on the lateral side of the cleft. Histological examination using serial sections were performed on 47 cases and showed evidence of dermal melanocytosis in 40 cases (85%) consisting of 33 (70%) without clinically detectable macules and 7 (15%) with obvious pigmented macules. The fusiform cells in the dermis were positive for dopa reaction and anti-melanocyte antibody. The high incidence of dermal melanocytosis is comparable to that of common Mongolian spots in Asian babies.

Cleft Lip↗
PubMed1989

Mechanical properties of poly(alkyl alpha-fluoroacrylate)s as denture-base materials.

alpha-Fluoro-substituted acryl polymers, poly(methyl alpha-fluoroacrylate) (PMFA) and poly(2,2,2-trifluoroethyl alpha-fluoroacrylate) (P3FFA) were investigated for extension to denture-base resins. PMFA, in which fluorine attaches to the polymer chain, had excellent mechanical properties: For instance, compressive and bending strength and bending modulus were 50% higher than those of PMMA. P3FFA, in which fluorines are substituted at the end of the pendant alkyl ester, showed poor mechanical properties. Contrary to expectations, the amount of water sorption of PMFA was about twice that of PMMA, while that of P3FFA was almost zero. Copolymers of MFA and 3FFA were prepared in an attempt to optimize the mechanical properties and the water sorption. The copolymer with 40% of 3FFA showed higher compressive, diametral tensile, and bending strength; in particular, the bending modulus and water resistance were about 35% and 20% higher, respectively, than those of PMMA. Improvement of the mechanical properties and increase of the water sorption of PMFA may be due to intermolecular forces induced by polarizability of the fluorine and carboxy group along the polymer chain. Decrease of the water sorption by fluorine substituted on the alkylester group as in P3FFA may be due to higher hydrophobicity and steric effect of the fluoroalkyl substitute.

Acrylic Resins↗
PubMed1988

Differential expression of c-myc gene and c-fos gene in premalignant and malignant tissues from patients with familial polyposis coli.

The expression of 8 oncogenes and the structures of 19 oncogenes were analyzed in 15 adenocarcinomas (12 primary and 3 metastatic), 18 adenomatous polyps, and 18 normal colonic mucosae derived from 19 patients with familial polyposis coli. The expression of c-myc gene was most elevated in carcinoma, and moderately elevated in adenoma, compared with corresponding normal colonic mucosa. In contrast, the expression of c-fos gene was markedly decreased in all samples of adenoma and carcinoma, compared with that of normal colonic mucosa. These characteristic expression patterns of c-myc and c-fos genes were revealed not only in familial polyposis coli but also in cases of nonhereditary colon carcinoma. Structures of the 19 oncogenes were not modified in either adenoma or carcinoma, except for amplification of the c-myc gene detected in one carcinoma, but not in adenoma, from the same patient. Analyses of the amplified c-myc gene suggest that gene duplication may relate to the mechanism of gene amplification. Thus, the enhanced expression of c-myc gene in adenoma and carcinoma may reflect the proliferative activity, while the c-fos gene may be a prerequisite to stabilize the state of terminal differentiation of colonic epithelial cells.

Adenomatous Polyposis Coli↗
PubMed1988

Existence of malfunctioning pro alpha2(I) collagen genes in a patient with a pro alpha 2(I)-chain-defective variant of Ehlers-Danlos syndrome.

Collagen synthesis was examined in skin fibroblasts from a patient with a variant of Ehlers-Danlos syndrome. The relative rate of collagen synthesis to total protein synthesis in the patient's fibroblasts was always one-half of that in fibroblasts from normal controls. Total collagen synthesis, as assessed by quantification of total hydroxyproline, was also significantly lower than that of controls, indicating that the rate of collagen synthesis by the patient's fibroblasts was decreased compared with that by normal fibroblasts. Analysis of procollagen and collagen components showed the absence of the pro alpha 2(I) chain and its derivatives. Dot-blot and Northern-blot analyses showed the patient's fibroblasts to contain less than 10% of the mRNAs for pro alpha 2(I) found in control fibroblasts. In spite of these results, Southern blot analysis of genomic DNA indicated the presence of the same number of genes for the pro alpha 2(I) collagen chain in the patient's fibroblasts as in control fibroblasts, suggesting malfunctioning pro alpha 2(I) collagen genes as the cause for failure of the patient's fibroblasts to synthesize pro alpha 2(I) collagen chains.

Adult↗
PubMed1988

A glycoprotein of oviductal origin alters biochemical properties of the zona pellucida of hamster egg.

Eggs were isolated from ovaries and oviducts of the golden hamster and the components of zonae pellucidae were examined using density gradient SDS-polyacrylamide electrophoresis. Zonae of ovarian eggs (ZP-OVA) had three major components corresponding to the so-called ZP-1, ZP-2, and ZP-3. Zonae of recently ovulated eggs collected from oviducts (ZP-OVI) had a 200-240 K component (ZP-O) in addition to the three components present in ZP-OVA. When ovarian and oviductal eggs were stained with FITC-conjugated B. simplicifolia-1 lectin (BS-1), which specifically binds to alpha-D-galactose- or alpha-N-acetyl-D-galactosamine-like terminal saccharide residues, ZP-OVI was intensely stained, while ZP-OVA was not. ZP-OVA gained the ability to bind to BS-1 after a brief treatment with oviduct extracts. These results suggest that biochemical properties of hamster zonae change after transport of eggs from ovary to the oviduct. The addition of the 200-240 K component of oviductal origin to preexisting zona components seems to be responsible for this change.

Animals↗
PubMed1988

Inhibition of in vitro fertilization by a monoclonal antibody reacting with the zona pellucida of the oviductal egg but not with that of the ovarian egg of the golden hamster.

A glycoprotein designated ZP-0 is secreted from the epithelial cells of the oviduct and is bound to the zonae pellucidae (ZPe) of the oviductal eggs. We have previously established a monoclonal antibody reacting with ZP-0, termed AZPO-8. In the present study, we have examined the effect of AZPO-8 on in vitro fertilization in the hamster. Treatment of the oviductal eggs with AZPO-8 at concentrations of more than 100 micrograms/ml resulted in: (1) the formation of "zona precipitation" on the outer region of the ZP; (2) inhibition of sperm binding to ZP; (3) the acquisition of resistance to protease treatment. Fertilization was inhibited by AZPO-8 in a dose-dependent manner. These results indicate that a monoclonal antibody (MoAb) to an additional component of ZP derived from the oviduct shows an inhibitory effect on fertilization in vitro.

Animals↗
PubMed1988

Estrogen binding component in the pilosebaceous tumor developed in Suncus murinus.

We transplanted a pilosebaceous tumor developed on the sidegland of Suncus murinus to male nude athymic (BALB/c-nu/nu) mice. This tumor can be transplanted to female hosts as well, with a lower rate of graft-taking and slower growth rate. In this study we demonstrated the presence of macromolecules which specifically bind to estrogen. Measurement of 17 beta-estradiol (E2) binding by a dextran-coated charcoal assay revealed that the number of binding sites and the dissociation constant were 22.3 +/- 4.6 fmol/mg protein and 1.4 +/- 0.24 X 10(-9) M, respectively. This binding was specific for E2 and diethylstilbestrol (DES). Sucrose gradient centrifugation of the [3H]E2-labeled cytosol yielded a sharp peak of radioactivity at 3.5S-4S under high salt conditions and a 9S peak with a shoulder at 3.5S under low salt conditions. This 3.5S shoulder was due to dissociation of [3H]E2 from the 9S peak during the centrifugation, since only the 9S peak was obtained by postlabeled density gradient analysis. An assay of the in vivo binding of [3H]E2 showed significant radioactivity in the nuclear extract from the tumor. This nuclear uptake was markedly decreased by simultaneous administration of 100-fold excess of E2. In tumor-bearing castrated nude mice, 1-100 micrograms/day of E2 did not affect tumor growth, whereas it counteracted the stimulative effect of testosterone propionate.

Animals↗
PubMed1988

Regulation of human estrogen receptor gene, epidermal growth factor receptor gene, and oncogenes by estrogen and antiestrogen in MCF-7 breast cancer cells.

It is generally believed that estrogen may act either as an initiator or as a promoter in carcinogenesis of human breast cancer. This estrogenic action is generally dependent on the estrogen receptor. In the human estrogen receptor, cDNA has a homology to V-erb-A oncogene. Experiments using MCF-7 human breast cancer cells were carried out to study the regulatory effect of estrogen and antiestrogen on RNA activities of oncogenes, estrogen receptor gene, and epidermal growth factor (EGF) receptor gene. The effect of estradiol on activation of estrogen and EGF receptor genes and myc, ras, and fos oncogenes was positive in relation to the concentrations of supplemented estradiol. In addition, the effects of antiestrogen (tamoxifen) were investigated. Tamoxifen suppressed MCF-7 cell growth, and spot hybridization of the RNA of MCF-7 cells revealed that RNA activities of estrogen and EGF receptor genes and myc, ras, and fos oncogenes were suppressed by tamoxifen. These results suggest that the three oncogenes and two receptor genes are partly regulated by estrogen and antiestrogen (tamoxifen) in MCF-7 human breast cancer cells. This regulatory system may have a role in carcinogenesis and in the treatment of human breast cancer.

Breast Neoplasms↗
PubMed1987

Production of recombinant rat viruses as a method of oncogene isolation in coculture medium.

A simple oncogene isolation was proved using the SD1-T rat embryonic cell line. The SD1-T cell line, which releases endogenous rat leukemia virus, was cocultured with (a) normal rat kidney cells transformed by cloned v-mos DNA, (b) the rat mammary tumor cell line (63SP), or (c) normal rat kidney cells transformed by 63SP DNA. Within 1 mo, oncogenic viruses were recovered from all three coculture supernatants. During this period, increase of oncogenic transcripts was observed in the cocultured cells. The oncogenic viruses appeared to contain the mos gene in cocultures (a) and ras-related sequences in cocultures (b) and (c). The emergence of virus containing mos from mos DNA-mediated normal rat kidney transformants demonstrated "rescue" of the active cellular oncogene by the rat leukemia virus. This coculture system seems to facilitate "rescue" of oncogenes functioning in the tumor and transformed cells.

Animals↗
PubMed1987

Idiopathic retroperitoneal fibrosis.

We treated a patient with idiopathic retroperitoneal fibrosis accompanied by right ureteral constriction. Pyelography, ureterography, and abdominal CT scan were pertinent diagnostics. Close collaboration between the surgeon and the urologist is required when attempting to treat such patients.

Humans↗
PubMed1987

A monoclonal antibody reacting with the zona pellucida of the oviductal egg but not with that of the ovarian egg of the golden hamster.

A monoclonal antibody (mAb) designated AZPO-8 was produced by hybridizing a mouse myeloma with spleen cells from BALB/c mice immunized with materials obtained from the hamster oviduct. With an immunofluorescence test, AZPO-8 reacted with the zona pellucida (ZP) of ovulated eggs in the oviduct (ZP-OVI) but not with the zona pellucida of eggs in the ovary (ZP-OVA). Using indirect enzyme immunostaining, this mAb reacted with epithelial cells of the oviduct, the uterus (especially the cervical epithelium) and the gastric mucosa, but not with other hamster tissues examined. The reactivity of antigen-positive tissues was abrogated by pretreatment of the tissues with periodic acid. Western blotting analysis revealed that AZPO-8 reacted with substances of broad molecular weight range, and the strongest reactivity was detected at a molecular weight of approximately 200,000 in both cases when extract of ZP-OVI or the hamster oviduct was applied on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel. AZPO-8 showed strong hemagglutination activity only to group A human red blood cells. These results indicated that (1) ZP-OVI had an antigen that was not detected on ZP-OVA, (2) ZP-OVI and the oviduct shared the same antigenicity, and (3) the antigenic determinant reactive with the mAb might be carbohydrate in nature. A possible role of this antigen in fertilization was discussed.

Animals↗
PubMed1987

[A case report of successful immunochemotherapy of metastatic renal cell carcinoma using UFT and PSK].

The authors have monitored a case of renal cell carcinoma metastatic to the supraclavicular cavity over a twenty-year period following surgical removal of a cancerous kidney. The subject was a 67-year-old male who had his right kidney removed in 1963 because of renal cell carcinoma. In September of 1983, complaints of pain and an enlarged tumor in the left supraclavicular cavity during a physical examination led to a pathological diagnosis of clear cell carcinoma. Although chemotherapy using FT-207+ PSK was ineffective, there was a response to UFT+ PSK therapy which was deemed effective according to the criteria of Koyama and Saito. The findings suggested that UFT was effective in this case.

Aged↗
PubMed1986

The laser method for efficient introduction of foreign DNA into cultured cells.

A minute hole upon a cultured cell, perforated with a finely focused laser beam, was found to repair itself within a short period of time. The procedure constitutes a new way of introducing exogenous gene materials dissolved in medium into cells. The 'laser-aided' DNA transfection is better than the existing methods because it allows the treatment of a large number of cells in a shorter time, and an improved success rate.

Animals↗
PubMed1986

Novel method for substance injection into the cell by laser beam--a study of the injection volume.

A DNA transfection method by laser microbeam pricking has been recently reported (Kurata, S. et al. Exp. Cell Res. 162, 372 (1986]. The volume of external fluid transferred into the cell by the method was determined through the injection of diphtheria toxin fragment A (Yamaizumi, M. et al. Cell 15, 245 (1978]. Using these results and the results on laser DNA transfection efficiency (Kurata, S. et al. Exp. Cell Res. 162, 372 (1986], the approximate number of DNA molecules necessary to transform the recipient cell was estimated.

Animals↗