Search PubMed⌕ Search

Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 91 records · Page 5Linked to original sources
PubMed2000

Neovascular Maculopathy Associated with Rubella Retinopathy.

Background: We report three eyes of two patients with rubella retinopathy which were associated with choroidal neovascularization in the macula.Cases: A 7-year-old girl (case 1) and a 12-year-old girl (case 2) whose mothers had suffered rubella during their pregnancy revealed typical rubella retinopathy in both eyes and neovascular maculopathy in one eye at their initial visit to our clinic. Neovascular maculopathy developed in another eye of case 1 after a follow-up of 10 months.Results: The clinical characteristics indicated that (1) sudden visual loss occurs in children, (2) there is no external trigger such as eye injury, and (3) the visual prognosis appears relatively good.Conclusion: Although neovascular maculopathy is rare in pediatric disease, the rubella retinopathy may have the potential to cause neovascular maculopathy.

Journal Article↗
PubMed2000

The JAK-inhibitor, JAB/SOCS-1 selectively inhibits cytokine-induced, but not v-Src induced JAK-STAT activation.

Recently, constitutive activation of JAK kinases (JAKs) and/or signal transducers and activators of transcription (STATs) has been reported in growing numbers of human cancer cells as well as oncogene-transformed cells. JAB/SOCS-1 has been shown to be an intrinsic JAK tyrosine kinase inhibitor and to suppress the cytokine-dependent JAK-STAT pathway. In this report, we investigated the effect of ectopic expression of JAB on v-Src-induced JAK-STAT activation. Forced expression of JAB in v-Src-transformed NIH3T3 cells neither suppressed phosphorylation of STAT3 and JAK1/JAK2 nor blocked STAT3-reporter gene activation. Colony forming assay also showed that JAB did not suppress v-Src-induced transformation of NIH3T3 cells, while dominant negative STAT3 suppressed it. In contrast, JAB could downregulate phosphorylation of STAT1 and STAT3 induced by interferon gamma (IFNgamma) and interleukin-6 (IL-6) plus soluble IL6 receptor (sIL-6R), respectively. Furthermore, in vitro kinase assay indicated that JAB suppressed hyperactivation of JAK1/JAK2 and JAK1 induced by IFNgamma and IL-6 plus sIL-6R respectively, but not v-Src-induced basal JAK1/JAK2 activity. Nevertheless, both JAK1/JAK2 activated by v-Src and that activated by IL-6 plus sIL-6R could similarly bind JAB. These results clearly demonstrate that JAB distinguishes cytokine-induced JAK-STAT signaling from v-Src-induced one and can not suppress the transformation with v-Src.

3T3 Cells↗
PubMed2000

Preparation of a monoclonal antibody to N(epsilon)-(Hexanonyl)lysine: application to the evaluation of protective effects of flavonoid supplementation against exercise-induced oxidative stress in rat skeletal muscle.

The monoclonal antibody to N(epsilon)-(hexanonyl)lysine (HEL), a novel adduct formed by the reaction of linoleic acid hydroperoxide and lysine, has been prepared and characterized. The obtained antibody specifically recognized the HEL moiety. Using the monoclonal antibody, we evaluated the protective effects of feeding eriocitrin, which is one of flavonoids in lemon fruit, on oxidative modification induced by exercise in rats. The supplementation of eriocitrin significantly suppressed the increase in HEL in the skeletal muscle by exercise. The result suggests that the determination of HEL may be a good method for evaluation of the protective effect of beneficial food factors against oxidative stress.

Aldehydes↗
PubMed2000

Effects of single and repetitive spreading depression on cerebral blood flow and glucose metabolism in cats: a PET study.

To clarify the effects of spreading depression (SD) on cerebral circulation and metabolism, we elicited a single or repetitive episode of SD and evaluated CBF and CMRglc three-dimensionally in normal cats (n=4, in each group) using a high-resolution positron emission tomography (PET) scanner. SD was evoked by applying KCl to the left occipital cortex. We then monitored DC potential changes with tungsten electrodes inserted into the left temporal cortex. CBF was measured twice before and three times (immediately, 30-60 min, and 60-120 min) following KCl application using [15O]H(2)O, and CMRglc was determined using 2-[18F]fluoro-2-deoxy-D-glucose immediately following the last CBF measurement. The following results were obtained: (1) a single episode of SD produced a temporary CBF increase, followed by a long-lasting hypoperfusion in the cortex, with no significant changes to CBF observed in the subcortex; (2) no significant CMRglc changes were observed in either cortical or subcortical regions following a single episode of SD; (3) a flow-metabolism uncoupling was observed in the cortical regions concurrently with persistent hypoperfusion; (4) repetitive SD produced significant CBF changes in the cortex; and (5) the cortical CMRglc increased as a result of repeated episodes of SD, with no significant changes observed in the subcortex. Thus, we succeeded in determining three-dimensionally the effects of single and repetitive SD on CBF and CMRglc in cats using a high-resolution PET scanner. The present study provides the first direct evidence of CBF-CMRglc uncoupling occurring concurrently with persistent hypoperfusion following SD.

Animals↗
PubMed2000

Electronic interactions in a new fullerene dimer: C(122)H(4), with two methylene bridges

The isolation of a new fullerene dimer, C(122)H(4), and its structural characterization by (13)C NMR and (1)H NMR spectroscopy and by UV/vis and IR spectroscopy are reported. The structure of this dimer consists of two fullerene cages, which are directly connected through two C-C bonds and two methylene bridges. Consequently, adjacent hexagonal faces of the two fullerene cages are arranged in a face to face manner. Molecular orbital calculations indicate that the proximity of the fullerene cages results in significant through space overlap in both the HOMO and LUMO. As a consequence of this overlap, the electrochemistry of the dimer shows electronic communication with stepwise reduction of each cage.

Journal Article↗
PubMed2000

Overexpression of CDC25B phosphatase as a novel marker of poor prognosis of human colorectal carcinoma.

There is evidence to suggest that CDC25B phosphatase is an oncogenic protein. To elucidate the role of CDC25B in colorectal carcinoma, we examined the expression of CDC25B at the mRNA and protein levels. Reverse transcription-PCR assay indicated that CDC25B was overexpressed in tumor tissues relative to normal mucosa in 6 of 10 cases. Using immunohistochemistry, we identified high expression of CDC25B in 77 of 181 colorectal cases (43%). Univariate analysis showed that high expression was a significant predictor for poor prognosis compared with low expression (5-year survival rate; 59% versus 82%, respectively; P < 0.0001). Multivariate analysis indicated that CDC25B was an independent prognostic marker (risk ratio for death, 3.7; P < 0.0001) even after controlling for various factors such as lymph node metastasis, tumor size, degree of differentiation, and depth of invasion. Furthermore, the level of CDC25B expression clearly predicted the outcome of patients with Dukes' B and Dukes' C tumors. On the other hand, CDC25A mRNA was overexpressed in 9 of 10 colorectal cancer cases, and immunohistochemistry for CDC25A showed high expression in 52 of 111 cases (47%), but no significant correlation with prognosis. Our findings suggest that CDC25B is a novel independent prognostic marker of colorectal carcinoma and that it may be clinically useful for selecting patients who could benefit from adjuvant therapy.

Adult↗
PubMed2000

Mammaglobin B gene as a novel marker for lymph node micrometastasis in patients with abdominal cancers.

Mammaglobin B is a recently-isolated gene speculated to belong to the uteroglobin gene family and is overexpressed in primary breast cancers. We investigated mammaglobin B mRNA expression in various cancers of the digestive system. Given the absence of mammaglobin B expression in normal lymph nodes, we also assessed the usefulness of mammaglobin B as a marker for lymph node micrometastases in cancer patients. Mammaglobin B gene transcripts were frequently detected by reverse transcriptase-polymerase chain reaction (RT-PCR) assay in primary tumors of the esophagus (2/3), stomach (7/7), colon (15/15), pancreas (4/6), common bile duct (6/6), cholangioma (2/2) and gall bladder (1/1). Mammaglobin B overexpression was observed in three of 15 cases (20%) of colon cancer, suggesting its possible contribution to colon carcinogenesis. Down-regulated mammaglobin B expression was observed in hepatoma cells in comparison with corresponding non-cancerous livers (3/3). RT-PCR assay of mammaglobin B detected 14 of 15 histologically positive lymph nodes from patients with gastric cancer, colon cancer and cholangioma. Seven of 32 (22%), three of nine (33%), and three of seven (43%) histologically negative nodes from patients with gastric, colon and cholangiocellular carcinoma, respectively, were found to express mammaglobin B mRNA. Our results showed that expression of mammaglobin B was frequently detected in cancers originating in digestive organs, especially adenocarcinomas, and that mammaglobin B gene detected by RT-PCR may be a potentially useful molecular marker for lymph node micrometastases of various digestive organ cancers.

Abdominal Neoplasms↗
PubMed2000

X-linked retinoschisis with point mutations in the XLRS1 gene.

BACKGROUND: X-linked retinoschisis (XLRS) is a relatively rare vitreoretinal dystrophy that causes visual loss in young men. Recently, a gene responsible for this disease, designated XLRS1, was identified, and several deleterious gene mutations were reported. OBJECTIVE: To analyze Japanese patients clinically diagnosed as having XLRS formutational changes in the XLRS1 gene. METHODS: Ten patients with XLRS underwent full ophthalmologic examination, including slitlamp biomicroscopy and dilated funduscopy. Genomic DNA was isolated from leukocytes, and all exons of the XLRS1 gene were amplified by polymerase chain reaction and analyzed using a direct sequencing method. RESULTS: Point mutations in the XLRS1 gene were identified in all 10 patients. The mutations were identical in each of 2 pairs of brothers. Six of the point mutations represented missense mutations, 1 was a nonsense mutation, and 1 was a frameshift mutation. Five of the mutations are newly reported herein. CONCLUSIONS: The discovery of new point mutations in this study increases the available information regarding the spectrum of genetic abnormalities and clinical manifestations of XLRS. However, the limited data failed to reveal a correlation between mutation and disease phenotype. CLINICAL RELEVANCE: Identification of mutations in the XLRS1 gene and expanded information on clinical manifestations will facilitate early diagnosis, appropriate early therapy, and genetic counseling regarding the prognosis of XLRS.

Adolescent↗
PubMed2000

Nuclear findings of ovarian surface epithelial tumors.

While cytoplasmic features of ovarian surface epithelial tumors are well-known, the nuclear findings have received little attention. We reviewed imprint cytology materials of the ovary which were collected at the Kawasaki Medical School Hospital between January 1989-July 1999, and identified 15 mucinous cystadenomas, 3 borderline mucinous tumors, 4 mucinous cystadenocarcinomas, 4 serous cystadenomas, 4 borderline serous tumors, 7 serous cystadenocarcinomas, 6 endometrioid carcinomas, and 2 clear-cell adenocarcinomas. We microscopically observed nuclear findings of the 45 cases. Coffee-bean nuclei were observed in 15.0%, 15.8%, and 10.1% of the tumor cells in mucinous adenomas, borderline mucinous tumors, and borderline serous tumors, respectively. The frequencies of the coffee-bean nuclei in the three tumors were higher than in the remaining tumors (P < 0.001). Intranuclear cytoplasmic inclusions were observed in 2.1% of the tumor cells in mucinous cystadenoma, and their frequency was significantly higher than that in cases of other surface epithelial ovarian tumors (P < 0.001). Semilunar-shaped nuclei were seen in all cases of mucinous cystadenomas and borderline mucinous tumors, and in 3 of 4 mucinous adenocarcinomas. The remaining surface epithelial tumors did not reveal the semilunar-shaped nuclei. In the cytology of the ovary, the semilunar nuclei are characteristic of mucinous tumors, and the intranuclear cytoplasmic inclusion may be a diagnostic clue to mucinous cystadenoma, when it is conspicuous. The coffee-bean nuclei can be seen in mucinous cystadenoma, borderline mucinous tumors, and borderline serous tumors.

Cell Nucleus↗
PubMed2000

Preliminary evaluation of [1-11C]octanoate as a PET tracer for studying cerebral ischemia: a PET study in rat and canine models of focal cerebral ischemia.

Octanoate is taken up into the brain and is converted in astrocytes to glutamine through the TCA cycle after beta-oxidation. We speculate that [1-11C]octanoate may be used as a tracer for astroglial functions and/or fatty acid metabolism in the brain and may be useful for studying cerebral ischemia. In the present study we investigated brain distribution of [1-11C]octanoate and compared it with cerebral blood flow (CBF) by using rat and canine models of middle cerebral artery (MCA) occlusion and a high resolution PET. In rats brain distribution of [15O]H2O measured 1-2 h and 5-6 h after insult was compared with that of [1-11C]octanoate measured 3-4 h after insult. Radioactivity ratios of lesioned to normal hemispheres determined with [15O]H2O were lower than those determined with [1-11C]octanoate. These results were confirmed by a study on a canine model of MCA-occlusion. Twenty-four hours after insult, CBF decreased in the MCA-territory of the occluded hemisphere, whereas normal or higher accumulation of [1-11C]octanoate was observed in the ischemic regions. The uptake of [1-11C]octanoate-derived radioactivity therefore increased relative to CBF in the ischemic regions, indicating that [1-11C]octanoate provides functional information different from CBF. In conclusion, we found that [1-11C]octanoate is a potential radiopharmaceutical for studying the pathophysiology of cerebral ischemia.

Animals↗
PubMed2000

Stenotrophomonas maltophilia endophthalmitis after intraocular lens implantation.

BACKGROUND: Stenotrophomonas maltophilia is an opportunistic, gram-negative bacillus. Endophthalmitis induced by S. maltophilia has been described in only two cases after intraocular lens implantation. We report S. maltophilia endophthalmitis in two patients with diabetes mellitus after intraocular lens implantation and compare the characteristics of the S. maltophilia-induced endophthalmitis with two previous cases. METHODS: A 68-year-old woman and a 74-year-old man with diabetes mellitus developed S. maltophilia endophthalmitis within 5 days of intraocular lens implantation. We performed intraocular lens removal and vitrectomy, which resolved the inflammation. No recurrences were found. RESULTS: Cultures grew S. maltophilia in both cases, and one of the organisms was multi-resistant. The final visual acuity was counting fingers and 0.3. The first case revealed a tractional retinal detachment during vitrectomy. CONCLUSIONS: S. maltophilia is a potential opportunistic intraocular pathogen, and the incidence of multiresistant S. maltophilia is increasing. S. maltophilia causes acute endophthalmitis, and its prognosis may not be poor unless the eye has a history of serious disease before the cataract surgery. The combined procedure of intraocular lens removal and vitrectomy was useful in resolving the inflammation and preventing recurrences.

Aged↗
PubMed2000

Predictability of the progress of secondary osteoarthritis after developmental dislocation of the hip, utilizing inferior edge (of the teardrop)--center (of the femoral head) distance.

We followed-up a group of patients in their youth and then in middle age after they had been treated for developmental dislocation of the hip, and studied whether we could predict the progress of osteoarthritis of the hip when the patients were in the "youth" stage. We studied 21 hips of 21 patients with unilateral dislocation that could be examined twice, in 1975 and 1995, in patients who were treated at our hospital between 1953 and 1963. We measured the acetabular-head index (AHI), center-edge angle (CE angle), and the Sharp angle, and our created index (inferior edge of the teardrop - center of the femoral head distance), and we divided this index by the distance of the inferior edges of the teardrops on both sides. Using these measured values, we studied whether we could predict changes in clinical and radiographic evaluation after a follow-up of 20 years. There was no significant correlation of clinical and radiographic results and AHI, CE angle, and the Sharp angle; however, there was a significant correlation with our created index. The index we created is relatively easily measured and enables us to make a more precise prognosis, in comparison with previously developed indices.

Adolescent↗
PubMed2000

Strategy for pulmonary atresia and intact ventricular septum.

Pulmonary atresia with an intact ventricular septum is characterized by varying degrees of right ventricular cavity hypoplasia. This factor is critical in determining the most appropriate surgical approach for each patient. We describe a patient who underwent definitive biventricular surgical repair in early infancy. We used an atrial septal defect patch with a one-way valve and performed a right ventricular overhaul after a balloon valvotomy.

Cardiac Surgical Procedures↗
PubMed2000

Biodistribution of 3,4-dihydro-5-[11C]methoxy-1(2H)-isoquinolinone, a potential PET tracer for poly(ADP-ribose) synthetase.

Poly(adenosine diphosphate-ribose) synthetase (PARS) is a nuclear enzyme that is activated by deoxyribonucleic acid (DNA) strand breaks and participates in DNA repair. Excessive PARS activation, however, leads to cell death due to depletion of adenosine triphosphate (ATP). To evaluate whether it is possible to detect excessive activation of PARS with positron emission tomography (PET), we examined the pharmacokinetics of 3,4-dihydro-5-[(11)C]methoxy-1(2H)-isoquinolinone ([(11)C]MIQO), a potent poly(ADP-ribose) synthetase inhibitor, in the brain of rats and monkeys. Although the uptake of [(11)C]MIQO in the brain of normal rats was low, [(11)C]MIQO was rapidly incorporated into and then quickly washed out from the brain. The uptake of the radiotracer in the brain of normal monkeys was also low; however, [(11)C]MIQO gave a distribution image that differed from that of cerebral blood flow obtained by [(15)O]water-PET. No localization of [(11)C]MIQO in the brain of normal monkeys was observed. Low accumulation of some radioactivity was also observed in muscles surrounding the brain of monkeys, but did not seem to interfere with measurement of [(11)C]MIQO uptake in the brain with PET. Thus, detection of [(11)C]MIQO uptake with PET may be useful for detecting PARS activity in ischemic injury.

Animals↗
PubMed2000

Identification and antioxidant activity of flavonoid metabolites in plasma and urine of eriocitrin-treated rats.

Eriocitrin, a flavonoid glycoside present in lemon fruit, is metabolized in vivo to a series of eriodictyol, methylated eriodictyol, 3,4-dihydroxyhydrocinnamic acid, and their conjugates. Plasma antioxidant activity increased following oral administration of aqueous eriocitrin solutions to rats. Eriocitrin metabolites were found in plasma and renal excreted urine through HPLC and LC-MS analyses. Eriocitrin was not detected in plasma and urine, but eriodictyol, homoeriodictyol, and hesperetin in their conjugated forms were detected in plasma of 4.0 h following administration of eriocitrin. In urine for 24 h, both nonconjugates and conjugates of these metabolites were detected. 3,4-Dihydroxyhydrocinnamic acid, which is metabolized from eriodictyol by intestinal bacteria, was detected in slight amounts with each form in 4.0-h plasma and 24-h urine. Eriocitrin was suggested to be metabolized by intestinal bacteria, and then eriodictyol and 3,4-dihydroxyhydrocinnamic of its metabolite were absorbed. Following administration of eriocitrin, plasma exhibited an elevated resistance effect to lipid peroxidation. Eriocitrin metabolites functioning as antioxidant agents are discussed.

Animals↗
PubMed2000

Standard for pattern electroretinography. International Society for Clinical Electrophysiology of Vision.

The pattern electroretinogram (PERG) is a retinal response evoked by viewing an alternating checkerboard or grating. It receives clinical and research attention because it can provide information about inner retinal cells and the macula. However, clinicians may have trouble choosing between different techniques for recording the PERG that have been described in the literature. The International Society for Clinical Electrophysiology of Vision has prepared a standard for a basic PERG recording procedure to aid new users in obtaining reliable responses and to encourage more uniformity among existing users.

Clinical Protocols↗
PubMed2000

Assessment of local cone on- and off-pathway function using multifocal ERG technique.

There is evidence that recording the photopic ON- and OFF-responses with long-duration stimuli is useful for determining the contribution of the cone ON- and OFF-pathways to the primate photopic electroretinogram (ERG). In this study, the optimal conditions for recording multifocal ON-OFF responses are described, and the technique is applied to normal subjects and two patients with unusual retinal diseases. The results from the normal subjects demonstrated that there were topographical variations of the photopic ERG waveform: when responses were normalized to the ON-response (b-wave) amplitude, the OFF-response (d-wave) amplitude increased with increasing eccentricity. The changes in the waveform in two patients suggested relatively greater defects of the hyperpolarizing or depolarizing bipolar cells. We conclude that the multifocal ERG technique with long-duration stimuli can be a useful tool to assess the function of local cone ON- and OFF-pathways in normal and diseased retinas.

Adult↗