Biomedical subjects

K Tsuchiya

Publications and source records attributed to K Tsuchiya.

At least 19 recordsLinked to original sources

PubMed2006

Correlation between the expression level of c-maf and glutathione peroxidase-3 in c-maf -/- mice kidney and c-maf overexpressed renal tubular cells.

Large mafs are transcriptional factors and members of the basic leucine zipper (b-Zip) superfamily. Since we previously identified expression of c-maf in mouse kidney, we presently investigated the mRNA expression profile in the kidney of c-maf gene knockout mice by using DNA microarray, and plasma glutathione peroxidase-3 (GPx3) was predominantly downregulated. We focused on the relation between the expression level of c-maf and GPx3 in vivo and in vitro. Since GPx3 is an antioxidant enzyme, oxidative stress was induced by exposing a culture cell derived from mouse renal tubules (mIMCD3) to hydrogen peroxide. Real-time PCR demonstrated that mRNA expression of both c-maf and GPx3 increased in parallel during exposure to oxidative stress in a time- and dose-dependent manner. Then, the mIMCD3 cells were transfected with c-maf-cDNA containing plasmid, which resulted in an increase in mRNA and protein expression of GPx3 compared with the control cells. Thus, c-maf may be transcriptional regulator of GPx3 expression and modulate the antioxidative pathway in the kidney.

Animals↗

PubMed2006

Reduced expression of Toll-like receptor 4 contributes to impaired cytokine response of monocytes in uremic patients.

Toll-like receptors (TLRs) play a pivotal role in pathogen recognition and subsequent cytokine synthesis by immune cells. Uremic patients have a high infectious morbidity, but it remains unclear if this arises from the defective innate immune responses related to TLRs. We studied TLR4 expression in monocytes and their intracellular cytokine synthesis in response to lipopolysaccharide (LPS) stimulation in 35 predialysis patients with chronic kidney disease (CKD) with or without predisposition to bacterial infections and 16 age-matched controls. Expression of TLR4 in unstimulated peripheral monocytes was determined by staining with anti-TLR4 antibody and analysis with flow cytometry. Monocytes were then stimulated by LPS, labeled with anti-CD14 antibody, and subjected to intracellular cytokine staining and flow cytometry. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, and IL-8 synthesis was examined in CD14(+) monocytes. TLR4 expression was constitutively diminished in CKD patients with reduced expression being more severe in those CKD patients who were predisposed to infections. Monocytes from these infection prone CKD patients exhibited significantly reduced synthesis of TNF-alpha, IL-1beta, IL-6, and IL-8 in response to LPS challenge compared with those from control subjects. The intensity of synthesis of each cytokine significantly correlated with TLR4 expression levels in monocytes (P<0.01). The capacity of monocytes to synthesize proinflammatory cytokines was significantly reduced in infection prone CKD patients, and this may possibly be due to the reduced monocyte expression of TLR4. Abnormal TLR4 expression by monocytes may play a role in the susceptibility of such patients to bacterial infections.

Aged↗

PubMed2006

FTY720 suppresses CD4+CD44highCD62L- effector memory T cell-mediated colitis.

FTY720, a sphingosine-derived immunomodulator, causes immunosuppression via enhancement of lymphocyte sequestration into secondary lymphoid organs, thereby preventing their antigen-activated T cell egress to sites of inflammation. FTY720 is highly effective in inhibiting autoimmunity in various animal models. However, there is little known about how FTY720 controls the migration property of memory T cells. Here, we demonstrated that FTY720 prevents the development of colitis induced by the adoptive transfer of lamina propria (LP) colitogenic effector memory CD4+ T cells (TEM cells; CD45RB(low)CD44(high)CD62L-) into severe combined immunodeficiency (SCID) mice and suppresses interferon-gamma, interleukin-2, and tumor necrosis factor-alpha production by LP CD4+ T cells. The numbers of spleen, peripheral blood, mesenteric lymph node, and LP CD4+ T cells in FTY720-treated mice were significantly reduced compared with those in control mice. Notably, LP CD4+ TEM cells as well as splenic CD4+CD45RBhigh T cells expressed several spingosine-1-phosphate receptors that are targets for FTY720. Furthermore, FTY720 also prevented the development of colitis induced by the adoptive transfer of splenic CD4+CD45RBhigh T cells into SCID mice. Collectively, the present data indicate that FTY720 treatment may offer the potential not only to prevent the onset of disease but also to treat memory T cell-mediated autoimmune diseases including inflammatory bowel diseases.

Animals↗

PubMed2006

Phylogeographic origin of Hokkaido house mice (Mus musculus) as indicated by genetic markers with maternal, paternal and biparental inheritance.

We examined intraspecies genetic variation in house mice (Mus musculus molossinus) from the northern third of the Japanese Islands, in order to obtain evidence of the history of mouse colonization that might have shaped the current genetic diversity. We extended the previous sampling of mitochondrial cytochrome b sequence and added information from the Y-linked Sry gene and ribosomal RNA gene surveys. We distinguish mitochondrial haplotypes characteristic of the North Asian musculus subspecies group (involving M. m. musculus and M. m. molossinus) as 'MUS', and that of the Southeast Asian castaneus subspecies group as 'CAS' (although the mice resemble MUS morphologically). There was a clear geographic partition of MUS and CAS types into southern and northern Hokkaido, respectively. Conversely, on Tohoku, the MUS and CAS types were interspersed without clear geographic subdivision. In contrast to the mtDNA data, all Hokkaido and Tohoku mice examined were found to possess a unique type for the Y-linked Sry gene, specific to Korea and Japan. Restriction site analysis of nuclear rDNA probe showed a consistent distribution of MUS and CAS types, as major and minor components, respectively, in the Hokkaido and Tohoku mice. These data support the previous notion that the Hokkaido and Tohoku mice experienced genetic hybridization between primary residents of CAS origin and MUS newcomers arriving via a southern route. The invasion of the MUS type could correspond with the evidence for arrival of prehistoric peoples. There are, however, alternative interpretations, including genetic admixture between MUS arriving by a southern route and CAS from a northern route.

Animals↗

PubMed2006

Visualization of cervical nerve roots and their distal nerve fibers by diffusion-weighted scanning using parallel imaging.

PURPOSE: To report a technique developed for visualizing cervical nerve roots and distal nerve fibers using diffusion-weighted magnetic resonance imaging employing parallel imaging. MATERIAL AND METHODS: We performed maximum intensity projection for a stack of isotropic axial diffusion-weighted images obtained with parallel imaging applying a motion-probing gradient in six directions with a b-value of 500 s/mm2 in a preliminary series of 13 subjects. RESULTS: This method worked well for visualizing the spinal cord and most of the nerve roots, the dorsal root ganglia, and proximal peripheral nerves. CONCLUSION: Although the technique remains limited in depicting the brachial plexus and distal nerves, the ability to visualize the proximal peripheral nervous system at the cervical level is promising.

Adult↗

PubMed2006

[Acute type A aortic dissection with partial disruption of the right coronary ostium; report of a case].

A 64-year-old man with a history of hypertension was admitted to another hospital, presenting with sudden chest pain. Although his symptoms resolved after admission, chest computed tomography (CT) revealed acute type A aortic dissection, and he was referred to our hospital for surgery. On arrival, his hemodynamic status was stable. Electrogram showed no ST-T change, and transthoracic echocardiography demonstrated pericardial effusion, mild aortic regurgitation and good left ventricular wall motion. We immediately decided on an emergency operation. Commencing a median sternotomy, the pericardial cavity was found to be filled with old blood. Standard cardiopulmonary bypass was instituted with right atrial drainage and right femoral arterial return, and with right upper pulmonary venous venting. When antegrade cold blood cardioplegia was selectively administered, we noticed the partial disruption of the upper aspect of the right coronary ostium. The right coronary sinus was resected in a scallop shape. Partial aortic root remodeling using a trimmed tube graft and coronary artery bypass grafting to the right coronary artery with saphenous vein were performed under deep hypothermic circulatory arrest. Weaning from cardiopulmonary bypass was not difficult. The postoperative course was uneventful.

Aortic Dissection↗

PubMed2005

Two cases of atypical melanocytic lesions in recessive dystrophic epidermolysis bullosa infants.

Summary Atypical melanocytic lesions (AtML) are known to be associated with epidermolysis bullosa (EB), mainly with the junctional subtype. We report two cases of AtML in two female infants with recessive dystrophic epidermolysis bullosa (RDEB). Both lesions were dark brown- to black-coloured, asymmetric-shaped macules, 3-4 cm in size, with an irregular border and were located on the forearms of two unrelated, 1-year-old female infants. On a clinical and pathological basis, the pigmented macules were diagnosed as AtML in EB patients. There are only a few reports describing in detail the clinical and histopathological features of AtML in RDEB, especially in infant cases. AtML may easily be misdiagnosed as malignant melanoma and, even in infant patients with RDEB, this should be included as one of the differential diagnosis of pigmented lesions.

Diagnosis, Differential↗

PubMed2005

Differentiation between solitary brain metastasis and high-grade glioma by diffusion tensor imaging.

We tested our hypothesis that fractional anisotropy (FA) maps of diffusion tensor imaging could be used to differentiate between a solitary brain metastasis and a high-grade glioma. In seven patients with a solitary metastasis and seven patients with a high-grade glioma, FA values of enhancing and non-enhancing parts of the tumour were compared. Additionally, we visually assessed FA maps. No significant difference in the FA values of either the enhancing or non-enhancing part was found between the two groups. In the visual assessment, displacement of subcortical white-matter fibres was found in five of the seven metastasis patients, but in only one glioma patient. Additionally, discrimination between tumour and oedema was possible in three of the seven metastasis patients, but not in any glioma patient. Although FA values are not helpful in differentiating between the two groups, visual differences in FA values can allow the differentiation. Displacement of white-matter fibres is another finding suggestive of metastasis.

Adolescent↗

PubMed2005

[Mitral valve repair for commissural prolapse due to infective endocarditis].

A 65-year-old man and a 51-year-old man underwent mitral valve repair for commissural prolapse due to infective endocarditis. On the occasion of repairing, folding plasty technique was employed to avoid relatively large annular plication after leaflet resection. Postoperative echocardiography showed no residual regurgitation and sufficient orifice area of the mitral valve. Folding plasty technique appeared to be simple and useful for repairing commissural prolapse due to infective endocarditis.

Aged↗

PubMed2004

Marked asymmetry of putaminal pathology in an MSA-P patient with Pisa syndrome.

We report on an autopsy case of a 62-year-old Japanese woman with a 2.5-year history of axial dystonia. She presented with a form of axial dystonia reminiscent of Pisa syndrome. The pathophysiological mechanism underlying forms of axial dystonia remains to be elucidated. We report here the histopathological findings of a multiple system atrophy of parkinsonian predominance (MSA-P) patient with Pisa syndrome.

Atrophy↗

PubMed2004

PCR-based identification and characterization of Burkholderia cepacia complex bacteria from clinical and environmental sources.

AIMS: To study the genotypic identification and characterization of the 119 Burkholderia cepacia complex (Bcc) strains recovered from clinical and environmental sources in Japan and Thailand. METHODS AND RESULTS: Based on the results of analysis by 16S rDNA RFLP generated after digestion with DdeI, the Bcc strains were differentiated into two patterns: pattern 1 (including Burkholderia vietnamiensis) and pattern 2 (including B. cepacia genomovar I, Burkholderia cenocepacia and Burkholderia stabilis). All strains belonged to pattern 2 except for one strain. In the RFLP analysis of the recA gene using HaeIII, strains were separated into eight patterns designated as A, D, E, G, H, I, J and K, of which pattern K was new. Burkholderia cepacia epidemic strain marker (BCESM) encoded by esmR [corrected] and the pyrrolnitrin biosynthetic locus encoded by prnC were present in 22 strains (18%) and 88 strains (74%) from all sources, respectively. All esmR-positive [corrected] strains belonged to B. cenocepacia, whereas most prnC-positive strains belonged to B. cepacia genomovar I. CONCLUSIONS: Strains derived from clinical sources were assigned to B. cepacia genomovar I, B. cenocepacia, B. stabilis and B. vietnamiensis. The majority of Bcc strains from environmental sources (77 of a total 95 strains) belonged to B. cepacia genomovar I, whereas the rest belonged to B. cenocepacia. On the basis of genomovar-specific PCR and prnC RFLP analysis, strains belonging to recA pattern K were identified as B. cepacia genomovar I. SIGNIFICANCE AND IMPACT OF THE STUDY: This work provides the genotypic identification of a collection of the Bcc strains from Japan and Thailand. RFLP analysis of the prnC gene promises to be a useful method for differentiating Burkholderia pyrrocinia from B. cepacia genomovar I strains.

Burkholderia Infections↗

PubMed2004

Atypical cause of hibernating myocardium due to complex cardiovascular lesions associated with Takayasu's arteritis.

Myocardial hibernation is recognised as chronic hypoperfusion of the myocardium and its functional recovery after surgical revascularisation has been described. A case of surgery for complex lesions including severe aortic valve regurgitation, coronary ostial stenosis, and aortic calcification (porcelain aorta) caused by Takayasu's arteritis is presented. The onset of left ventricular functional improvement after aortic valve replacement and coronary revascularisation were indicative of preoperative atypical myocardial hibernation caused by aortic valve disease and coronary artery disease associated with Takayasu's arteritis.

Aortic Diseases↗

PubMed2004

[Arch aneurysm after coronary artery bypass grafting, report of a case].

A 63-year-old woman had undergone graft replacement for abdominal aortic aneurysm in 1992, and coronary artery bypass grafting (CABG) using saphenous vein grafts in 1995. At that time arch aneurysm (4.7 cm) was pointed out. Chest computed tomography (CT) showed dilated arch aneurysm (7 cm) in 2000. We performed an operation for arch aneurysm. As the bypass graft to obtuse marginal branch was close to aneurysm, aortic closs clamp was impossible. So we injected potassium chloride to aortic root and cardiac arrest was obtained. Total arch replacement for arch aneurysm was performed and postoperative course was uneventful.

Aorta, Thoracic↗

PubMed2004

[Aortic dissection (DeBakey type I) associated with pseudoaneurysm 21 years after aortic valve replacement; report of a case].

We report a case of 63-year-old male who suffered from aortic dissection associated with pseudoaneurysm 21 years after aortic valve replacement. Preoperative computed tomography (CT) scan and aortography revealed DeBakey type I dissecting aneurysm with maximum diameter of 70 mm on ascending aorta and calcified pseudoaneurysm at previous aortotomy. He underwent modified Bentall procedure preserving previous mechanical valve and total aortic arch replacement with elephant trunk technique. Postoperative course was uneventful.

Aortic Dissection↗

PubMed2003

Congenital pulmonary-systemic collateral vein without obstructed left atrial egress is associated with conotruncal anomalies.

We present a case of congenital pulmonary systemic collateral vein associated with truncus arteriosus. Pulmonary systemic collateral vein with nonobstructed left atrial egress is different from those with obstructed left atrial egress in that it is functionally redundant. Including this case, 8 patients among 33 reported cases with pulmonary systemic collateral veins have had nonobstructed left atrial egress. Association with conotruncal anomalies in 4 of these 8 patients, as well as the reported finding that neural crest cells are distributed not only in the conotruncus but also in the cardinal vein, indicates that neural crest cells play roles in remodeling of the systemic venous system.

Collateral Circulation↗

PubMed2003

Progressive supranuclear palsy presenting with primary progressive aphasia--clinicopathological report of an autopsy case.

We report a Japanese autopsy case of progressive supranuclear palsy (PSP). The male patient was 74 years old at the time of death. At age 64, he developed non-fluent aphasia that progressed slowly over 8 years, eventually associated with behavioral abnormality, postural instability, and dysphagia at 2 years prior to his death. Magnetic resonance imaging of the brain at age 73 demonstrated marked atrophy of the frontal lobes, particularly on the left side. Neuropathological examination revealed the typical pathology of PSP: loss of neurons, gliosis, occurrence of neurofibrillary tangles, oligodendroglial coiled bodies, and tuft-shaped astrocytes in the frontal cortex, associated with argyrophilic threads in the underlying white matter, in the basal ganglia, including the thalamus, globus pallidus, and subthalamic nucleus, and in the brainstem nuclei, including the substantia nigra, pontine nucleus, and inferior olivary nucleus. No astrocytic plaques or ballooned neurons were observed. Protein analysis revealed accumulation of hyperphosphorylated tau of 68 and 64 kDa consisting of the four repeat tau isoforms. We conclude that the present case represented PSP with an 8-year history of primary progressive aphasia (PPA). Although focal cortical symptoms in PSP are rare or absent, we should keep in mind the possibility of atypical PSP in which cortical pathology is predominant, particularly in the frontal lobe, and could result in PPA.

Aged↗

PubMed2003

Diffusion-weighted MRI of subdural and epidural empyemas.

We reviewed diffusion-weighted images (DWI) from eight patients with subdural and four with epidural empyemas to assess the possibility of differentiating between these lesions by DWI. The signal intensities of the empyemas on DWI, and maps of the apparent diffusion coefficient (ADC) were analysed in seven patients. In seven of the eight patients with subdural empyema, the lesions appeared as areas of high signal. The ADC maps confirmed that these areas were the result of restricted diffusion. (In the remaining patient, the lesion showed a mixture of high and low signal.) The epidural empyemas contained areas of low signal in all four patients; part of the empyema was isointense or gave high signal in two. DWI may be an adjunct to conventional sequences for differentiating between subdural and epidural empyemas.

Adult↗

PubMed2003

Diffusion-weighted MRI of the cervical spinal cord using a single-shot fast spin-echo technique: findings in normal subjects and in myelomalacia.

We have implemented a new diffusion-weighted MRI (DWI) sequence based on the single-shot fast spin-echo technique. We hypothesised that this would add information to conventional MRI for diagnosis of lesions of the cervical spinal cord. DWI was performed using a technique in which echo collection after the application of motion-probing gradients was done in the same manner as in the single-shot fast spin-echo technique. We first imaged six healthy volunteers to demonstrate the cervical spinal cord using the sequence. Then we applied the sequence to 12 patients with cervical myelomalacia due to chronic cord compression. The spinal cord was well seen in all subjects without the distortion associated with echo-planar DWI. In the patients, lesions appeared as areas of low- or isointense signal on DWI. Calculated apparent diffusion coefficients of the lesions (3.30+/-0.38x10(-3) mm(2)/s) were significantly higher than those of normal volunteers (2.26+/-0.08x10(-3) mm(2)/s). Increased diffusion in areas of cervical myelomalacia, suggesting irreversible damage, can be detected using this technique.

Adult↗