Search PubMed⌕ Search

Biomedical subjects

H Miyamoto

Publications and source records attributed to H Miyamoto.

At least 109 records · Page 6Linked to original sources
PubMed1999

Up-regulation of the alpha2,6-sialyltransferase messenger ribonucleic acid increases glycoconjugates containing alpha2, 6-linked sialic acid residues in granulosa cells during follicular atresia of porcine ovaries.

The sugar chains in cellular glycoconjugates have many biological functions. Extensive morphological development and remodeling occur in the ovary of female animals. This caused us to study glycobiological characteristics of ovarian cells, particularly granulosa cells that undergo apoptosis during follicular atresia. The lectin Sambucus sieboldiana agglutinin (SSA) specific for Siaalpha2,6Gal/GalNAc showed positive staining for granulosa cells only in atretic follicles of porcine ovaries by lectin histochemistry. Lectin blot analysis for SSA demonstrated specific glycoproteins only in atretic follicles. Furthermore, we performed analysis of backbone structures of SSA-positive glycans carried by granulosa cell glycoproteins increased during atresia by glycosidase treatment. Most of these structures were Siaalpha2,6Galbeta1,4GlcNAc on complex-type N-glycans, suggesting that only ST6Gal I of four distinct alpha2,6-sialyltransferases catalyzes alpha2,6-sialic acid transfer in most of the increased glycoproteins of granulosa cells during follicular atresia. Reverse transcription-polymerase chain reaction analysis demonstrated that the expression of ST6Gal I mRNA was up-regulated in granulosa cells during atresia. These results suggested that the alteration of glycoconjugates by ST6Gal I in granulosa cells during atresia is involved in some processes of ovarian follicular atresia and granulosa cell apoptosis.

Animals↗
PubMed1999

Basosquamous carcinoma after ultraviolet therapy with artificial sunlight.

We report a 63-year-old Japanese man with basosquamous carcinoma developing after ultraviolet therapy with artificial sunlight. Because he had had an eczematous lesion on the right leg five years previously, he had received ultraviolet therapy with artificial sunlight from a mercury-quartz lamp for a total of 30 sessions over a 3-year period. Physical examination revealed an irregular erythematous plaque measuring 5 x 6 cm, with slight eruptions and erosions, on the right leg. A brownish plaque, measuring 9 x 12 cm, surrounded the erythematous plaque. Histopathologically, in the nests of atypical cells in the dermis, nuclear palisading was present at the edge of each tumor cluster. Adjacent clusters exhibited transitions to squamous cells and contained horn pearls. Most of the cells of the epidermis and adnexa were atypical, but cells of the normal adnexal epithelium extended over the atypical cells of the epidermis in an umbrella-like fashion in other lesions. We believe that, in the present case, artificial sunlight therapy caused solar keratosis and that this developed into basosquamous carcinoma. To our knowledge, skin cancer developing after ultraviolet therapy with artificial sunlight without PUVA has not previously been reported in the English literature.

Carcinoma, Basosquamous↗
PubMed1999

Grouping of 20 reference strains of Legionella species by the growth ability within mouse and guinea pig macrophages.

20 Reference strains of Legionella species, isolated from human, were classified according to their ability to grow within thioglycolate-induced peritoneal macrophages of mice and guinea pigs. Inbred and congenic mice were used to study the effect of the natural resistance genes Lgn1 and Bcg that are expressed phenotypically in the mouse macrophages. The Lgn1 gene controlled the intracellular growth of Legionella pneumophila Philadelphia-1 and Legionella jordanis GIFU 12657, but the Bcg gene did not affect the intracellular growth of any organism examined. Based on these results and the growth ability in guinea pig macrophages, the 20 reference strains were divided into four groups. This grouping will help us to understand a variety of modes of interaction between Legionella species and macrophages.

Animals↗
PubMed1999

Effects of fluorescent light on growth of bovine retinal pigment epithelial cells in vitro incubated with linoleic acid or linoleic acid hydroperoxide.

Light-induced peroxidation of polyunsaturated fatty acids (PUFA) may generate lipid hydroperoxides, which may have toxic effects on retinal pigment epithelial (RPE) cells in vitro. We investigated the effects of cool-white fluorescent light on the RPE cells incubated with linoleic acids (LA) or linoleic acid hydroperoxides (LHP) and the influence of antioxidative enzymes. We measured the bovine RPE cell number after exposure to fluorescent light (610 and 1,200 lux) in the presence of LA or LHP. Furthermore, the effects of superoxide dismutase (SOD) and catalase on LA- or LHP-treated RPE cells were also examined. Both LA and LHP treatment increased RPE cell number under weak illumination (610 lux), but dose-dependently decreased the number of cells exposed to strong illumination (1,200 lux). With exposure to strong illumination, LA caused a greater reduction in RPE cell number than LHP. Multiple linear regression analysis showed that the number of RPE cells was significantly decreased in a manner dependent on the interactions of the illuminance of light and the concentrations of LA or LHP. The antioxidative enzymes significantly ameliorated the damage to RPE cells from LA or LHP and exposure to light. Therefore, the exposure to fluorescent light augmented the cytotoxic effects of LA and LHP on RPE cells, and this effect is likely to be mediated by reactive oxygen species.

Animals↗
PubMed1999

[Bacteriological studies of traveller's diarrhoea (6). Analysis of enteropathogenic bacteria at Kansai Airport Quarantine Station from September 4th, 1994 through December 1996].

During the period of investigation from Sept. 4, 1994 to Dec, 1996, a total of 11,446,534 overseas travellers were quarantined at Kansai Airport Quarantine Station, and 22,187 voluntarily reported of episodes suffering from diarrhoea. Bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained. 1) Various enteropathogenic bacteria were isolated from 33.3% of the stools examined. Bacterial species isolated were as follows: Plesiomonas shigelloides, 2,066 cases (66.7%); Vibrio parahaemolyticus, 358 cases (11.6%); Aeromonas sobria, 360 cases (11.6%); Shigella spp., 291 cases (9.4%); Salmonella spp., 183 cases (5.9%); A. hydrophila, 126 cases (4.1%); and V. cholerae non-O1, 121 cases (3.9%). However, ETEC was not done with an object of test. 2) In 502 cases (16.2%), plural enteropathogenic bacteria were isolated from single patient, suggesting high frequency of a mixed infections. 3) From Feb. to Mar. 1995, thirteen cases cholera were found from patients who had travelled to Bali, Indonesia. Cases with enteropathogenic bacteria other than V. cholerae O1 were found without any seasonal variation. 4) The major regions where the travellers were infected with the pathogens are as follows: Vibrio spp., were from only Asia; Shigella, widely distributed but especially in India and Indonesia; P. shigelloides and Salmonella, widely distributed. 5) Among the Shigella strains, S. sonnei were isolated the most, followed by S. flexneri, S. boydii and S. dysenteriae. A strain of S. boydii provisional serovar E 16553 was isolated from a patient infected in India. 6) Among the Salmonella serovars, Salmonella Enteritidis was isolated the most frequently (49 cases, 25.7%). 7) 265 (89.2%) of 297 Shigella strains, 52 (27.2%) of 19] Salmonella strains, and 19 (95.0%) of 20 V. cholerae O1 were resistant to one or more drugs tested (SM. CP. TC. KM. ABPC. NA. OFLX). 8) All of the 20 V. cholerae O1 strains were Ogawa, E1 Tor. All of them were toxigenic strains. 9) The most frequently isolated serovar of V. parahaemolyticus was O3: K6. 89.8% of all V. parahaemolyticus strains were positive for thermostable direct hemolysin (TDH) gene, and 14.6% of them were positive for TDH-related hemolysin (TRH) gene by DNA-probe or PCR method.

Asia, Southeastern↗
PubMed1999

[Clinical analysis on an outbreak of SRSV-gastroenteritis with 644 patients emerged in Shizuoka Prefecture].

Small round structured viruses (SRSV) are the major cause of acute non-bacterial enterogastritis and have a characteristic of breaking out with mass victims as food poisoning. The outbreak usually occurs among school children from school lunches in Japan. A case in adults is relatively rare. The SRSV food poisoning with 644 adult victims carried through lunch box broke out, which may be the biggest number in adult cases in the world. This is the report describing its outlines, analytical result of clinical symptoms and fecal microbial examination. The average latent period was 37 hours, the time was mostly (47%) between 24-36 hours. The most emerged symptom was diarrhea and followed nausea, abdominal pain, vomiting and high fever. The older patients showed a higher rate of diarrhea and fewer one of nausea and fever. 15 patients complained of eye symptom. This number should not be neglected. It may be a characteristic of the disease. SRSV detection test with PT-PCR method of feces was done on 36 patients and 24 patients were positive. The most sensitive primer was Yuri/nested/22F/R. In Japan, lunch-service has become a industry advancing monopolization and wide areazation. SRSV make easily contamination to food, therefore if mass victim food-poisoning occurs, this should be considered initially.

Adolescent↗
PubMed1999

[Serum antibodies to rubella virus in healthy individuals with indirect immunofluorescent method].

To investigate sensitivity to rubella virus (RV) in healthy individuals, we examined levels of antibodies to RV in sera by an indirect immunofluorescence assay (IFA) and compared levels of antibodies by IFA with those by a hemagglutination inhibition (HI) assay. Of 114 healthy individuals, we detected antibodies to RV in serum specimens from 103 (90.3%) by IFA and in those from 109 (95.6%) by HI assay. The peak value of levels of antibodies by HI assay was 4 fold higher than that by IFA. When levels of antibodies by IFA were less than 32, levels of antibodies by HI assay ranged from < 8 to 1024. We did not detect anti-rubella antibodies of IgM class in all serum specimens and detected anti-rubella antibodies of IgA class in serum from only 1 individual by IFA. We detected antibodies to rubella in sera from 51 (94.4%) by IFA and in sera from 52 (96.3%) by HI assay of 54 individuals who reported having had rubella, and in sera from 23 (88.5%), by IFA and in sera from 26 (100%) by HI assay of 26 individuals reported having been vaccinated. Also, we detected anti-rubella antibodies in sera from 13 (76.5%) by IFA and in sera from 15 (88.2%) by HI of 17 individuals who reported having had neither rubella nor vaccination. In serum from 1 individual who reported having had rubella, we detected antibodies to rubella by IFA but not by HI assay. In serum specimens from 2 individuals who reported having had rubella vaccination, from 3 having had vaccination, from 2 having had neither rubella nor vaccination, we detected anti-rubella antibodies by HI assay but not by IFA. On the other hand, by both assays, we detected antibodies to RV in all sera of individuals who reported having had rubella and been vaccinated. The serodiagnosis, at least, by two methods is necessary to prevent individuals from rubella virus infection, because of following results: 1) influence of an inhibitor in serum specimens was thought to be variable. 2) The results measured by IFA were differed from those by HI assay in some individuals. 3) It is difficult in diagnosis of rubella from clinical symptoms alone. Also, it might be required to use vaccine to the individual who lacks detectable antibodies to rubella in serum by any method to prevent rubella infection.

Adult↗
PubMed1999

Induction of prophages of enterohemorrhagic Escherichia coli O157:H7 with norfloxacin.

Norfloxacin (NFLX) caused induction of prophages VT1 and VT2 of enterohemorrhagic Escherichia coli O157 at subinhibitory concentrations. In time course experiments, we observed the following sequential events: upon induction, the phage genomes underwent multiplication; the amount of stx genes increased; and subsequently, large quantities of toxins VT1 and VT2 were produced. Further studies showed that the molecular mechanism of prophage induction is closely related to the RecA system since the prophage VT2 was not induced with NFLX in a recA mutant strain.

Coliphages↗
PubMed1999

Development of functional zonation in the rat adrenal cortex.

In an attempt to elucidate the mechanism(s) through which the functional adrenal cortex is established, we analyzed immunohistochemically the expression of various markers for the adrenocortical zones, i.e. the zona glomerulosa (zG), the zona fasciculata (zF), and the zona reticularis (zR), as well as markers for the medulla, and further examined the distribution and behavior of DNA-synthesizing cells in rat adrenal glands during development. The results showed that 1) separation of the cortex and medulla, and the development of functional zonation in the cortex began at around the time of birth, 2) at fetal stages when cortical zonation was not established, DNA-synthesizing cells were found scattered throughout the gland, where they proliferated without significant migration, and 3) after birth in the adrenal cortex with established cortical zonation, DNA-synthesizing cells were localized near the undifferentiated zone between zG and zF, and then they migrated centripetally. Cell death appeared to occur in the innermost portion of the cortex, where many resident macrophages are present. These findings illustrate basic processes underlying adrenal development and suggest that the undifferentiated region is apparently the stem cell zone of the adrenal cortex that maintains the cortical zonation.

Adrenal Glands↗
PubMed1999

Prolongation of the effective duration of cytomedical therapy by re-injecting SK2 hybridoma cells microencapsulated within alginate-poly(L)lysine-alginate membranes into human interleukin-6 transgenic mice.

We previously reported that SK2 hybridoma cells that secreted anti-human interleukin-6 (hIL-6) monoclonal antibodies (SK2 mAb) were microencapsulated within alginate-poly(L)lysine-alginate (APA) membranes (APA-SK2 cells) for immunoisolation, and a single intraperitoneal injection of these APA-SK2 cells remarkably improved IgG1 plasmacytosis in hIL-6 transgenic mice (hIL-6 Tgm). However, the duration of the effectiveness of APA-SK2 cells as a cytomedicine was unfortunately limited. In this study, we attempted to re-inject APA-SK2 cells into hIL-6 Tgm for the purpose of prolonging the cytomedical therapy. In hIL-6 Tgm re-injected with APA-SK2 cells, the plasma IgG1 level did not show any increase in 37 week old mice, and their survival time was at least three times longer than those of untreated hIL-6 Tgm. These results suggest that re-injected APA-SK2 cells survived and secreted SK2 mAb in the allogeneic mice. Thus, the limited duration of the cytomedical effects of APA-SK2 cells was probably caused by the disappearance of the inner space of microcapsules for cell proliferation, not by the rejection of the host's immune system. Therefore, if we can regulate the proliferation of the cells microencapsulated within a semipermeable membrane, we may be able to develop a cytomedicine which will continue its function longer after a single injection.

Alginates↗
PubMed1999

Craniofacial skeletal abnormalities in anomalous calves with clefts of the face.

Thirteen anomalous calves with clefts of the face were morphologically examined, and craniofacial skeletons were studied in detail. According to the type and site of the cleft, four groups could be distinguished: median cleft lip and jaw (CLJ); median cleft lip, jaw, and palate (CLJP); lateral CLJ; and cleft palate (CP), including unilateral and bilateral type. Craniofacial skeletal abnormalities were observed in several bones at the roof, wall, and floor of the nasal cavity and at the boundary portion between the nasal and cranial cavities. Fissure formation at the cranial sutures, partial absence of the nasal process of the incisive bone, and opening of the bony palate were characteristic changes in median CLJ and CLJP, lateral CLJ, and CP, respectively. Furthermore, various associated changes were recognized in the median and paramedian skeletal elements of the face and other organs. The morphological changes of craniofacial skeletons with various types of clefts of the face depended on the site and degree of the cleft formation and reflected developmental errors of the facial embryonic segments. These changes would suggest disorders of the correlated development of facial processes and of other fetal organs of the face. For these conditions, etiologically hereditary cases were negative.

Animals↗
PubMed1999

Abnormalities of extracellular matrices and transforming growth factor beta1 localization in the kidney of the hereditary nephrotic mice (ICGN strain).

ICR-derived strain with glomerulonephritis (ICGN) is a strain of mice with hereditary nephrotic syndrome with an unidentified cause. Based on histopathological and biochemical data, ICGN mice are considered to be a good experimental model for human idiopathic nephrotic syndrome. In the present study, we histochemically investigated the changes in localization of extracellular matrix (ECM) components and transforming growth factor beta1 (TGF-beta1). Strong immunohistochemical staining of basal membrane ECM components (collagen IV and laminin) and interstitial ECM components (type III collagen and fibronectin) were demonstrated in glomeruli and tubulointerstitum of ICGN mice as compared with those of sex and age-matched ICR mice, used as normal healthy controls. Marked type I collagen and tenascin deposition, which were not detected in the glomeruli of ICR mice, were seen in the glomeruli of ICGN mice. A remarkable increase in active-TGF-beta1 was also detected only in glomeruli of ICGN mice, but not in those of ICR mice. Furthermore, strikingly increased alpha-smooth muscle actin, a marker of activated glomerular mesangial cells, was demonstrated in the glomeruli, mainly in the mesangial cells, of ICGN mice. These findings indicated that ECM components are increased in the glomerulus and tubulointerstitum of ICGN mice, and that active-TGF-beta1 induces such increases in ECM components. The present findings may contribute to elucidation of the pathogenic mechanisms of hereditary nephrotic syndrome in ICGN mice and, in future, human idiopathic nephrotic syndrome.

Animals↗
PubMed1999

Differential induction of androgen receptor transactivation by different androgen receptor coactivators in human prostate cancer DU145 cells.

Recently identified androgen receptor (AR) coactivators were used in this study to determine whether the specificity of sex hormones and antiandrogens could be modulated at the coactivator level. We found that ARA70 is the best coactivator to confer the androgenic activity on 17beta-estradiol. Only ARA70 and ARA55 could increase significantly the androgenic activity of hydroxyflutamide, a widely used antiand rogen for the treatment of prostate cancer. None of the AR coactivators we tested could significantly confer androgenic activity on progesterone and glucocorticoid at their physiological concentrations (1-10nM). We also found that ARA70, ARA55, and ARA54, but not steroid receptor coactivator-1 (SRC-1) and Rb, could significantly enhance the delta5-androstenediol-mediated AR transactivation. Furthermore, in comparing the relative specificity of these coactivators to AR in DU145 cells, our results suggested that ARA70 has a relatively higher specificity and that SRC-1 can enhance almost equally well many other steroid receptors. Finally, our data demonstrated that AR itself and some select AR coactivators such as ARA70 or ARA54 could, respectively, interact with CBP and p300/CBP-associated factors that have histone acetyl-transferase activity for assisting chromatin remodeling. Together, our data suggest that the specificity of sex hormones and antiandrogens can be modulated by some selective AR coactivators. These findings may not only help us to better understand the specificity of the sex hormones and antiandrogens, but also facilitate the development of better antiandrogens to fight the androgen-related diseases, such as prostate cancer.

Androgen Antagonists↗
PubMed1999

Multi-label image analysis of secretory cell juxtaposition in the sheep pituitary gland.

An image analysis system, assigned different pseudocolors to different types of immunolabeled cells, allowed us to make a montage from two images of the respective types of cells. This system was therefore used for simultaneous identification of two or more types of immunolabeled cells in the sheep anterior pituitary. Morphometry--including a neighboring proportion defined as the probability of a cell type adjoining other cell types--was performed. We also conducted a simulation of an artificial cell mass with an image analyzer to evaluate the effects of cell populations on the neighboring proportion. Simulation analysis showed that the predominant cell type tended to have a higher neighboring proportion, while rarer cell types had lower proportions according to their small population density. In the sheep pituitary gland, the neighboring proportions against PRL-, GH-immunolabeled cells were high (about 65% and 55%, respectively), according to their large populations. The neighboring proportion of LH beta-immunolabeled cells to the same type of cells was lower (11%) than that against other types of cells. It was thus suggested that LH cells were scattered throughout the anterior lobe. The neighboring proportion of ACTH-immunolabeled cells to the same type of cells was somewhat higher, but that of ACTH cells to PRL cells was low (52%). Accordingly, this cell type was often distributed in clusters. These quantitative results confirmed the topographical characteristics of secretory cells deduced from visual observation. In addition, a low topographical affinity between PRL and ACTH cells was indicated.

Adrenocorticotropic Hormone↗
PubMed1999

Differential induction of the androgen receptor transcriptional activity by selective androgen receptor coactivators.

Several new androgen receptor (AR) cofactors, associated to the ligand binding domain of AR, have been identified by our group and named AR associated protein (ARA)70, ARA55, and ARA54. Our previous reports have suggested that the cofactor ARA70 can confer the androgenic effect from 17 beta-estradiol (E2) and antiandrogen to AR. It is of interest for us to compare and determine if the specificity of sex hormones and antiandrogens could be modulated by different coactivators. Our results indicate that ARA70 is the best coactivator to confer the androgenic activity on E2. Only ARA70 and ARA55 could increase significantly the androgenic activity of hydroxyflutamide, a widely used antiandrogen for the treatment of prostate cancer. Furthermore, as compared to the relative specificity of these coactivators to AR in the prostate cancer DU145 cells, our results suggest that ARA70 has a relatively higher specificity. Together, our data suggest that the specificity of sex hormones and antiandrogens can be modulated by some selective AR coactivators. These findings may not only help us to better understand the specificity of the sex hormones and antiandrogens, but also to facilitate the development of better antiandrogens or androgens to fight the androgen-related diseases, such as prostate cancer.

Androgens↗
PubMed1999

Effect of focal X-ray irradiation on experimental choroidal neovascularization.

PURPOSE: Radiation therapy has been used to treat choroidal neovascularization (CNV) in patients with age-related macular degeneration. The in vivo effect of applying focal x-ray irradiation to the eye of rabbits with experimental CNV was investigated. METHODS: CNV was induced in the rabbit eyes by subretinal implantation of gelatin hydrogel microspheres impregnated with basic fibroblast growth factor. Three weeks after implantation, 17 of 34 eyes with CNV lesions accompanied by fluorescein leakage were irradiated with a single dose of 20 Gy; the other 17 eyes were not irradiated and served as the controls. The eyes were examined before irradiation and 1, 2, and 4 weeks after irradiation, by indirect ophthalmoscopy and fluorescein angiography. The degree of a decreasing amount of fluorescein leakage from the CNV lesions after irradiation was graded using a computerized image analysis system and was compared in the irradiated and nonirradiated eyes. These eyes were also examined histologically and immunohistochemically. RESULTS: Fluorescein leakage from the CNV lesions had significantly decreased in the eyes irradiated with 20 Gy compared with the control eyes, throughout the study period (P < 0.05). Histologic and immunohistochemical studies at 4 weeks after irradiation demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the irradiated eyes were less than those of the control eyes. CONCLUSIONS: Focal x-ray irradiation at the ocular region effectively reduced experimental CNV activity. These results support the possibility that radiation therapy may be beneficial in treating CNV.

Animals↗