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Yutaka Imamura

Publications and source records attributed to Yutaka Imamura.

At least 19 recordsLinked to original sources
PubMed2006

Hybrid exchange-correlation functional for core, valence, and Rydberg excitations: core-valence-Rydberg B3LYP.

The core-valence-Rydberg Becke's three-parameter exchange (B3)+Lee-Yang-Parr (LYP) correlation functional (CVR-B3LYP) is proposed as a means to improve descriptions of Rydberg excitations of core-valence B3LYP (CV-B3LYP). CV-B3LYP describes excitations from both core and occupied valence orbitals to unoccupied valence orbitals with high accuracy but fails to describe those to Rydberg orbitals. CVR-B3LYP, which adopts the appropriate portions of Hartree-Fock exchange for unoccupied valence and Rydberg regions separately, overcomes the disadvantage of CV-B3LYP. Numerical assessment confirms that time-dependent density functional theory calculations with CVR-B3LYP succeed in describing not only core excitations but also Rydberg excitations with reasonable accuracy.

Journal Article↗
PubMed2006

Drusen, choroidal neovascularization, and retinal pigment epithelium dysfunction in SOD1-deficient mice: a model of age-related macular degeneration.

Oxidative stress has long been linked to the pathogenesis of neurodegenerative diseases; however, whether it is a cause or merely a consequence of the degenerative process is still unknown. We show that mice deficient in Cu, Zn-superoxide dismutase (SOD1) have features typical of age-related macular degeneration in humans. Investigations of senescent Sod1(-/-) mice of different ages showed that the older animals had drusen, thickened Bruch's membrane, and choroidal neovascularization. The number of drusen increased with age, and exposure of young Sod1(-/-) mice to excess light induced drusen. The retinal pigment epithelial cells of Sod1(-/-) mice showed oxidative damage, and their beta-catenin-mediated cellular integrity was disrupted, suggesting that oxidative stress may affect the junctional proteins necessary for the barrier integrity of the retinal pigment epithelium. These observations strongly suggest that oxidative stress may play a causative role in age-related retinal degeneration, and our findings provide evidence for the free radical theory of aging. In addition, these results demonstrate that the Sod1(-/-) mouse is a valuable animal model to study human age-related macular degeneration.

Animals↗
PubMed2006

Time-dependent density functional theory calculations for core-excited states: assessment of standard exchange-correlation functionals and development of a novel hybrid functional.

A new hybrid functional for accurate descriptions of core and valence excitations, the core-valence Becke's three-parameter exchange (B3)+Lee-Yang-Paar (LYP) correlation functional (CV-B3LYP), is proposed. The construction of the new hybrid functional is based on the assessment that B3LYP performs well for properties concerning valence electrons and Becke's half-and-half exchange+LYP functional (BHHLYP), which includes 50% portion of Hartree-Fock exchange, performs well for core excitations. By using the appropriate portions of Hartree-Fock exchange for core and valence regions separately, CV-B3LYP overcomes the disadvantages of BHHLYP and B3LYP, which give inferior descriptions of valence and core excitations, respectively. Density functional theory (DFT) calculations with the CV-B3LYP functional reproduce core- and valence-orbital energies close to those of BHHLYP and B3LYP, respectively. Time-dependent DFT calculations with the CV-B3LYP functional yield both core- and valence-excitation energies with reasonable accuracy.

Journal Article↗
PubMed2006

Autopsy case of disseminated Trichosporon inkin infection identified with molecular biological and biochemical methods.

Trichosporon species are usually opportunistic pathogens. Disseminated trichosporonosis is uncommon but is increasingly reported with a high mortality rate, especially in immunocompromised patients. Although Trichosporon asahii and T. mucoides are known as the most common pathogens of disseminated trichosporonosis, cases of systemic infection due to T. inkin have been reported recently. However, no autopsy case of disseminated T. inkin infection has been reported. Herein is presented an autopsy case of disseminated trichosporonosis caused by T. inkin in a 30-year-old man with allogenic peripheral blood stem cell transplantation for acute myelocytic leukemia. In the present case, identification of T. inkin was performed with morphological, molecular biological and biochemical methods. It is difficult to make a diagnosis of Trichosporon infection on only histological examination; therefore, molecular biological and biochemical methods are needed in a diagnosis of disseminated trichosporonosis.

Adult↗
PubMed2006

Retrospective analysis of cord blood transplantation on 62 adult patients with advanced hematological malignancies.

The Japan Cord Blood Network was established in 1999 and 8 institutions from the Kyushu Hematology Organization Study Group had performed cord blood transplantation (CBT) 67 times on 62 patients with advanced hematological malignancies from 1999 to 2004, which included acute and chronic leukemias in 34 patients, non-Hodgkin's lymphoma in 14, adult T-cell leukemia in 11 and others in 3 patients. The median age was 44 and disease status was no remission on 50 patients prior to CBT. Myeloablative conditioning regimens were used in 27 patients while 35 patients received non-myeloablatives. Engraftment could not be determined in 25 patients and the median survival time was 70 days. Thirteen patients were alive from 288 to 1277 days and 49 had been expired. The causes of death were the underlying disease in 19 patients, severe infection in 14 and graft-versus-host disease in 3 and miscellaneous in the remaining patients. This retrospective study shows that some patients with far-advanced hematological malignances could be successfully treated with CBT at the expense of many early deaths due to early relapse and severe infection. It is of importance that the appropriate indication for CBT should be discussed between transplant experts and patients and their families in each case.

Adolescent↗
PubMed2005

Rapid quantitative analysis of human cytomegalovirus DNA by the real-time polymerase chain reaction method.

CONTEXT: Human cytomegalovirus (CMV) infection is a progressive and life-threatening complication in immunocompromised patients even now. Therefore, early and accurate treatment based on rapid and certain detection is needed to prevent fatal CMV infection diseases. OBJECTIVE: To study a quicker, simpler, and less expensive method of quantitative analysis using real-time polymerase chain reaction based on the SYBR Green I method of CMV detection for appropriate treatment of CMV infection in immunocompromised patients. DESIGN: We quantified 50 samples tested by direct immunoperoxidase staining of leukocytes with peroxidase-labeled monoclonal antibody (C7-HRP test), 30 samples from healthy persons, and 47 samples from 7 patients suspected of having CMV infection diseases. We used the primer set in the pp65 gene of CMV and whole blood without a preparatory process. The setting for the study was the First Department of Pathology, Kurume University School of Medicine, St Mary's Hospital, and the Gene Section of the Clinical Laboratory at St Mary's Hospital, Fukuoka, Japan. RESULTS: The results obtained with this method corresponded well with conventional C7-HRP tests and demonstrated excellent reproduction. Additionally, the results were better correlated with the clinical course than were C7-HRP tests. CONCLUSIONS: This method was more useful than the C7-HRP test as a rapid diagnostic test for early treatment of CMV infection. This test also demonstrated its usefulness for monitoring CMV infection during treatment using ganciclovir. Moreover, it was quicker, simpler, and cheaper than other real-time polymerase chain reaction methods.

Adult↗
PubMed2004

Intraoperative breakage of a 25-gauge vitreous cutter.

PURPOSE: To report breakage of a 25-gauge vitreous cutter during vitreous surgery. DESIGN: Interventional case report. METHODS: A 60-year-old woman was referred for management of an epiretinal membrane at the macula. Visual acuity was 20/100 in the affected left eye. Vitreous surgery using a 25-gauge vitrectomy system was carried out with a combination of conventional cataract surgery. RESULTS: The vitreous cutter was lodged within the sclerotomy cannula after peripheral vitrectomy and was pulled together with the cannula. The cannula was reinserted by trocar, but as the floating peeled epiretinal membrane was dissected with the vitreous cutter, the tip of the cutter was broken and was aspirated with the membrane. Stereoscopic microscopy and scanning electron microscopy demonstrated that the edge that had broken at the cutter port was smooth. CONCLUSION: Although 25-gauge instruments remain useful, care should be taken against rare surgical complications related to their fragility.

Catheterization↗
PubMed2004

Intermittent and recurrent hepatomegaly due to glycogen storage in a patient with type 1 diabetes: genetic analysis of the liver glycogen phosphorylase gene (PYGL).

We report a 19-year-old woman who had a history of type 1 diabetes with recurrent glycogen accumulation in the liver. During her infantile period she presented with no hepatomegaly nor growth retardation. On admission she was diagnosed with diabetic ketoacidosis (DKA). She also had hepatomegaly and elevated transaminase levels, but these abnormalities had resolved after administration of insulin. However, 4 weeks after DKA marked hepatomegaly and elevated transaminases were reappeared with simultaneous hypoglycemia which suggested an impaired glycogenolysis in the extraordinary conditions. We supposed the partial deficiency of liver glycogen phosphorylase activity in this patient and analyzed the liver glycogen phosphorylase gene (PYGL). Deduced amino acid sequence of the PYGL in this patient was completely identical to that reported by Burwinkel et al. (Y15233), however, the nucleotide sequence of PYGL cDNA was heterozygous for substitutions at positions Asp339 (GAT to GAC) on exon 9 and Ala703 (GCT to GCC on exon 17, respectively. These SNPs were also screened in 51 Japanese normal subjects by PCR-based direct sequencing or PCR-RFLP method. The same genotype observed in this patient was detected in 2 of 51(3.9%) normal subjects. These results suggest that the structure of PYGL coding sequence in this patient is unlikely to account for her excessive liver glycogen accumulation. Further studies including genetic analysis on the promoter region of the gene are necessary to clarify the etiology of susceptibility to excessive liver glycogen storage in patients with type 1 diabetes.

Adult↗
PubMed2003

Characterization of AOC2 gene encoding a copper-binding amine oxidase expressed specifically in retina.

We have previously cloned a human, retina-specific, amine oxidase gene (RAO, gene symbol: AOC2), a member of the copper-binding amine oxidase super family. AOC2 shares sequence identity with the human kidney amine oxidase gene (KAO, gene symbol: AOC1) and the vascular adhesion protein-1 gene (VAP-1, gene symbol: AOC3). For further analysis of AOC2, the sequences surrounding the human AOC2 and the complete mouse and partial rat homologue of AOC2 were cloned for characterization. Real-time quantitative PCR, in situ hybridization, and immunohistochemistry were performed to determine the specific expression of AOC2 in the mouse retina and especially in the retinal ganglion cells. Our results demonstrated that the copper-binding motif and the enzyme active site of AOC1 and AOC3 were both conserved in mouse AOC2. The human and mouse AOC2 was flanked by two genes, the Psme3 gene for PA-28 gamma subunit and, surprisingly, the AOC3 gene. Rat AOC2 contained a stop codon that terminated the peptide length to 127 amino acids. The presence of human and rat AOC pseudogene in this region, in addition to the tandemly positioned two AOC genes, indicates the possibility of successful AOC3 replication to retina-specific AOC2 for human and mouse but unsuccessful for rat.

Amine Oxidase (Copper-Containing)↗
PubMed2003

Severe proliferative retinopathy progressing to blindness in a japanese woman with takayasu disease.

PURPOSE: To report a patient with Takayasu disease with severe proliferative retinopathy progressing to bilateral blindness. A 57-year-old Japanese woman suffering from Takayasu disease for 16 years manifested severe proliferative retinopathy in both eyes, leading to blindness due to optic atrophy. DESIGN: Interventional case report. METHODS: A 57-year-old Japanese woman suffering from Takayasu disease for 16 years underwent a comprehensive opthalmologic examination. Panretinal photocoagulation and vitrectomy were performed on both eyes. SETTINGS: Institutional practice. RESULTS: At initial examination, the patient was found to have severe proliferative retinopathy with tractional retinal detachment in both eyes. The retinal detachments were repaired by the vitrectomy, however, the patient developed bilateral blindness due to optic atrophy. CONCLUSIONS: Patients with a long history of Takayasu disease can demonstrate severe proliferative retinopathy that may be resistant to photocoagulation and/or vitreous surgery. Ocular ischemia can lead to blindness from ischemic optic neuropathy.

Blindness↗
PubMed2003

Increased concentration of pentosidine, an advanced glycation end product, and interleukin-6 in the vitreous of patients with proliferative diabetic retinopathy.

To investigate the relationship between advanced glycation end products (AGEs) and interleukin-6 (IL-6) in the development of diabetic retinopathy, we determined the concentrations of pentosidine, a well-characterized AGE, and IL-6 in the vitreous of 62 patients with proliferative diabetic retinopathy (PDR) and 50 non-diabetic control subjects. We also investigated the effect of AGEs on the production of IL-6 by human retinal Müller cells. The levels of pentosidine and IL-6 in the vitreous of patients with PDR were significantly higher compared with controls. In patients with PDR with vitreous hemorrhage (VH), the mean vitreous concentration of IL-6 was significantly higher than that in PDR patients without VH. There was a strong positive correlation between the vitreous levels of pentosidine and IL-6. Levels of IL-6 were strikingly higher in the vitreous compared with the serum and there was no correlation between IL-6 concentrations in the two fluids. Treatment of Müller cells with AGEs for 48 h resulted in a dose-dependent increase of IL-6 in the culture medium. These results suggest that increased formation of AGEs in the vitreous may be involved in the development of diabetic retinopathy by inducing the production of IL-6 from retinal Müller cells.

Adult↗
PubMed2003

[Infection control for the treatment of hematological malignancies: a survey of the Kyushu Hematology Organization for Treatment Study Group (K-HOT)].

The Kyushu Hematology Organization for Treatment Study Group (K-HOT) consisted of 22 institutions specializing in hematology in Kyushu. This study is aimed at reviewing the daily practice of infection control for the treatment of hematological malignancies in our group. Nominal questionnaires were mailed to the hematology department in each institution from November 2001 to April 2002. For the first general surveys, 19 of 22 (86%) institutions responded. The second survey was mailed to the 19 respondents and 17 answered the detailed questionnaires with a response rate of 89%. Prophylactic use of trimethoprim-sulfamethoxazole (ST) against Pneumocystis carinii and anti-mycobacterial drugs in patients who had a history of tuberculosis was routine especially for patients with adult T-cell leukemia/lymphoma (ATL). Furthermore, the neutrophil counts to start a granulocyte-colony stimulating factor appeared to be high in ATL as compared with other hematological malignancies. In the setting of autologous stem cell transplantation (SCT), prophylactic use of acyclovir, immunoglobulin and ST was not routine and was reduced in duration, if used at all, as compared with allogeneic SCT. For allogeneic SCT, the cumulative dose of immunoglobulin significantly varied from institutions to institutions. The benefit of this study is the ability to recognize practical management patterns for infection control.

Hematologic Neoplasms↗
PubMed2003

[Endoscopic local ablation therapy (ELAT) for hepatocellular carcinoma--inventive approaches to achieve radical treatment and to expand the indication of ELAT].

We introduce some inventive approaches in endoscopic local ablation therapy (ELAT) for patients with hepatocellular carcinoma (HCC). ELAT is applied in cases of HCC when the tumor is smaller than 3 cm on the surface of the liver (smaller than 4 cm with extrahepatic growth), and tumor numbers < or = 3. Appropriate use of the laparoscopic, thoracoscopic and hand-assisted approaches, suitable preceding embolizations with the angiographic technique, a combination of ablation therapy, and the use of CO2-angio US, DIMON puncture system and cluster needle are important. If necessary, additional surgeries such as endoscopic hepatectomy, laparoscopic cholecystectomy or laparoscopic devascularization must be performed together. As a result, it will be possible to expand the indication of ELAT safely and radically.

Carcinoma, Hepatocellular↗
PubMed2002

[CD 56-positive acute myeloid leukemia (AML-M 1) with t(16;21) (p11;q22) presenting an extramedullary tumor in the right breast at relapse].

A 46-year-old woman was diagnosed as having acute myeloid leukemia (M 1) with translocation t(16;21) (p11;q22). The leukemic cells were positive for CD 13, CD 33, CD 34, CD 41, CD 56 and HLA-DR. After induction chemotherapy, the patient achieved complete remission (CR). However, 8 months later she relapsed with various additional chromosomal abnormalities. Although the patient achieved a 2nd CR after re-induction chemotherapy, the patient had extramedullary tumors in the right breast twice and relapse occurred frequently. The tumor cells were characterized by the same immunophenotypes and t(16;21) with additional 1 q trisomy. Although there was no evidence of hematological relapse, another type of 1 q trisomy was observed. Furthermore, an increase of abnormalities with 1 q trisomy was noted concomitant with re-increase in the number of blasts. The patient underwent allogeneic bone marrow transplantation (BMT), but she died from BMT complications. The case could have been a karyotype of t(16;21) with additional chromosomal abnormalities through consecutive approaches. Because of the high occurrence rate of relapse, we consider various additional chromosomal abnormalities and the expression of CD 56 as prognostic factors of this condition.

Breast Neoplasms↗
PubMedDate not supplied

Bilateral, nearly simultaneous anterior ischemic optic neuropathy complicated by diabetes and bilateral, small, crowded optic discs.

BACKGROUND: Bilateral simultaneous anterior ischemic optic neuropathy (AION) is uncommon. We report a case of bilateral and nearly simultaneously occurring AION. CASE: A 61-year-old man was referred to our hospital with bilateral optic disc edema. OBSERVATIONS: Visual field testing demonstrated inferior nasal defect OD and inferior defect OS. Fluorescein angiography showed a delay of dye filling in the superior part of the optic disc in both eyes. The patient had poorly controlled diabetes. A mild increase in erythrocyte sedimentation rates and creactive protein was observed, but the results of temporal artery biopsy were negative. His optic discs were small and lacked biological cups, which has been identified as a risk factor for developing AION. CONCLUSIONS: The complications of the structural anomaly, also known as "disc at risk," and diabetes might have caused the bilateral and nearly simultaneously occurring AION.

Blood Pressure↗
PubMedDate not supplied

Renin-angiotensin system in proliferative diabetic retinopathy and its gene expression in cultured human müller cells.

PURPOSE: To determine if the renin-angiotensin system (RAS) is involved in diabetic retinopathy, we measured the levels of angiotensin-converting enzyme (ACE) and angiotensin II in the vitreous of patients with proliferative diabetic retinopathy (PDR). We also investigated whether the genes of the RAS factors were expressed by cultured human Müller cells. METHODS: Vitreous samples were collected during vitreous surgery from patients with PDR, and from patients with idiopathic macular hole, who served as controls. The concentration of ACE was analyzed, and the level of angiotensin II was quantitatively determined by double antibody radioimmunoassay. In addition, the cDNA, prepared from the mRNA extracted from cultured human Müller cells, was used as a template for reverse transcriptase-polymerase chain reaction with primers selected for renin, angiotensinogen, ACE, and angiotensin receptor type I. RESULTS: The mean concentration of ACE was 0.82 +/- 0.73 IU/L at 37 degrees C in the PDR group, which was significantly higher than the 0.05 +/- 0.07 IU/L at 37 degrees C in the controls. The mean concentration of angiotensin II was 8.77 +/- 4.57 pg/mL in the PDR group, which was significantly higher than the 5.1 +/- 1.7 pg/mL in the controls. mRNA for renin, angiotensinogen, ACE, and angiotensin receptor type I was detected in cultured human Müller cells. CONCLUSIONS: The RAS is locally activated in eyes with PDR, and Müller cells may play a role in this local activation.

Angiotensin II↗