Search PubMed⌕ Search

Biomedical subjects

Hideaki Tanaka

Publications and source records attributed to Hideaki Tanaka.

At least 37 records · Page 2Linked to original sources
PubMed2005

Expression pattern of LINGO-1 in the developing nervous system of the chick embryo.

We isolated a chick homologue of LINGO-1 (cLINGO-1), a novel component of the Nogo-66 receptor (NgR)/p75 neurotrophin receptor (NTR) signaling complex, and examined the expression of cLINGO-1 in the developing brain and spinal cord of the chick embryo by in situ hybridization and immunohistochemistry. cLINGO-1 was expressed broadly in the spinal cord, including the ventral portion of the ventricular zone, and motor neurons. cLINGO-1 was also expressed in the dorsal root ganglion and boundary cap cells at dorsal and ventral roots. In the early embryonic brain, cLINGO-1 was first expressed in the prosencephalon and the ventral mesencephalon, and later in the telencephalon, the rostral part of the mesencephalon and some parts of the hindbrain. cLINGO-1 was also expressed in the ventral part of the neural retina and trigeminal and facial nerves. We also found that cLINGO-1, cNgR1 and p75NTR were expressed in overlapped patterns in the spinal cord and the dorsal root ganglion, but that these genes were expressed in distinct patterns in the early embryonic brain.

Amino Acid Sequence↗
PubMed2005

Novel soluble molecule, Akhirin, is expressed in the embryonic chick eyes and exhibits heterophilic cell-adhesion activity.

Akhirin, a novel secreted protein of 90 kDa, has been identified using signal sequence trap cDNA screening of an embryonic day 6 chicken lens cDNA library. Akhirin consists of one LCCL (Limulus factor C, Coch-5b2, and Lgl1) domain and two von Willebrand factor domains and displays high structural homology to vitrin and cochlin. The earliest expression of Akhirin is observed in the head ectoderm overlying the lens vesicle at stage 17 and in the retinal pigment epithelial layer at stage 22. It is persistently expressed in the ciliary marginal zone and in lens epithelium cells throughout embryonic eye development. Immunostaining with anti-Akhirin monoclonal antibody revealed a punctate distribution of Akhirin protein on living transfected cells. Cell adhesion and cell aggregation experiments showed that Akhirin has heterophilic cell-adhesion activity. Based on these observations, we hypothesize that Akhirin is involved in eye development.

Amino Acid Sequence↗
PubMed2005

Sedation-free colonoscopy.

PURPOSE: The administration of sedative drugs at colonoscopy has its drawbacks, such as increasing the rate of complications and the cost. There are a number of potential advantages to performing colonoscopy without sedation. The aim of this study is to evaluate patient tolerance and acceptance during sedation-free colonoscopy. METHODS: Pain during sedation-free colonoscopy was evaluated in consecutive series of 675 patients in a prospective manner from January 1, 2003, to February 18, 2004. We recorded the degree of patient pain during colonoscopy, willingness to undergo sedation-free colonoscopy in the future, the complication rate, and the intubation time. The assisting endoscopy nurses and patients independently assessed the pain level immediately after the procedure using a four-point pain scale (nil, mild, moderate, severe). RESULTS: Almost all colonoscopies (99.6 percent: 672/675) were successful. There were four complications related to colonoscopy (bleeding after polypectomy). Patients and nurses rated pain by a four-point pain scale as follows. For the patients: nil, 69.6 percent (470/675); mild, 28.0 percent (189/675); moderate, 2.2 percent (15/675); severe, 0.1 percent (1/675). For the nurses: nil, 76.1 percent (514/675); mild, 22.7 percent (153/675); moderate, 0.9 percent (6/ 675); severe, 0.3 percent (2/675). Patients rarely suffered from severe pain during carefully performed colonoscopies. The pain level of almost all colonoscopies was acceptable by patients, with only six patients (1.0 percent) stating that they would never undergo a colonoscopy without sedation in the future because of unbearable pain. CONCLUSIONS: This study suggests that carefully performed sedation-free colonoscopy rarely causes complications and is well accepted by most patients. Sedation-free colonoscopy is more cost-effective, may be safer, and should be offered as an alternative to colonoscopy with sedation.

Adolescent↗
PubMed2005

Prospective evaluation of factors predicting difficulty and pain during sedation-free colonoscopy.

PURPOSE: Colonoscopy can be painful for patients and difficult for colonoscopists; however, it is hard to predict how painful or difficult the examination will be. This study was designed to identify factors that predict pain and difficulty during sedation-free colonoscopy. METHODS: A total of 848 consecutive sedation-free colonoscopies were evaluated in a prospective manner. Factors were recorded, including patient pain, intubation time, demographic data, history of abdominal surgery, bowel preparation status, diverticular disease, bowel habits, anxiety level, and number of previous colonoscopies. These factors were analyzed to determine their association with pain and difficulty. RESULTS: Almost all colonoscopies (845/848; 99.6 percent) were successful. Univariate analyses showed that lower body mass index, younger age, female gender, anxiety level, first time, intubation time, preparation status, previous hysterectomy, and previous gynecologic surgery were predictors of patient pain, and lower body mass index, female gender, anxiety level, preparation status, previous hysterectomy, previous gynecologic surgery, and constipation were predictors of difficulty of intubation. Multivariate logistic regression analyses revealed that lower body mass index, younger age, intubation time, preparation status, previous hysterectomy, and antispasmodic agent use were predictors of patient pain, and lower body mass index, female gender, constipation, preparation status, and previous hysterectomy were predictors of difficulty of intubation. CONCLUSIONS: By use of intubation time and patient pain, several patient characteristics were identified that may predict technical difficulty and pain associated with the procedure. These findings have implications for the practice and teaching of colonoscopy.

Adolescent↗
PubMed2005

Evaluation of cingulate gyrus blood flow in patients with liver cirrhosis.

Although neuropsychological tests are commonly applied to detect minimal hepatic encephalopathy (HE) in patients with liver cirrhosis (LC), they provide no information about the cerebral regions involved. Recently, it has been reported that some populations of alcoholic cirrhotics, with mild HE, have reduced cerebral metabolic rate for glucose in bifrontal cortices and in the anterior cingulate gyrus. We evaluated the degree of reduction in blood flow at the anterior cingulate gyrus and the frontal lobes in cirrhotic patients who underwent single photon emission computed tomography (SPECT). Data were obtained from 47 cirrhotic patients and 47 subjects without LC. Three radiologists unaware of the results of laboratory tests visually evaluated the transaxial, coronal, and sagittal views of SPECT. The area and the degree of blood flow reduction in the anterior cingulate gyrus and frontal lobes were scored. Reduced blood flow in the anterior cingulate gyrus was observed in most LC patients. In patients without overt HE, poor performance in neuropsychological tests was correlated with reduced cerebral blood flow in the anterior cingulate gyrus. Blood flow in the anterior cingulate gyrus as measured by SPECT may be a simple and good indicator of cerebral functional changes in patients with LC.

Aged↗
PubMed2005

Accumulation of 8-nitroguanine in the liver of patients with chronic hepatitis C.

BACKGROUND/AIMS: Nucleic acid damage by reactive nitrogen and oxygen species may contribute to inflammation-related carcinogenesis. To investigate the extent of nucleic acid damage in hepatitis C virus infection and its change after interferon treatment, we measured 8-nitroguanine and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the liver of patients with chronic hepatitis C (CHC) before and after interferon therapy. METHODS: Hepatic accumulation of 8-nitroguanine and 8-OHdG was immunohistochemically evaluated in 20 CHC patients and 7 control patients with non-alcoholic fatty liver. RESULTS: Immunoreactivities of 8-nitroguanine and 8-OHdG were strongly detected in the liver from patients with CHC, but not in control livers. 8-Nitroguanine accumulation was found not only in infiltrating inflammatory cells, but also hepatocytes particularly in the periportal area. The accumulation of 8-nitroguanine and 8-OHdG increased with inflammatory grade (8-nitroguanine; P = 0.0019, 8-OHdG; P = 0.0009). In the sustained virological responder group after interferon therapy, 8-nitroguanine and 8-OHdG accumulation were markedly decreased in the liver (8-nitroguanine; P = 0.018, 8-OHdG; P = 0.018). CONCLUSIONS: In this study, we demonstrated for the first time that 8-nitroguanine accumulated in the liver of patients with CHC. 8-Nitroguanine is a useful biomarker to evaluate the severity of HCV-induced chronic inflammation in relation to hepatocellular carcinoma.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2005

Expression and molecular characterization of spherical particles derived from the genome of the hyperthermophilic euryarchaeote Pyrococcus furiosus.

Spherical particles (SPs) of approximately 30 nm in diameter were found in the hyperthermophilic archaeon Pyrococcus furiosus. The SPs contained no nucleic acid and were composed of a single 39-kDa protein. The amino acid sequences of the amino-terminal and internal fragments were identical to portions of the deduced amino acid sequence of the putative 38.7-kDa protein encoded by the genome of P. furiosus, suggesting that the protein was expressed from the genome of P. furiosus. This possibility was confirmed by the observation that the 38.7-kDa protein expressed in Escherichia coli reacted specifically with the antibody against purified SPs, and it also formed SPs similar to those found in P. furiosus. Of the 345 amino acid residues in the 38.7-kDa protein, the amino-terminal 100 amino acids exhibited strong homology to putative proteins from other species of Pyrococcus, while the remaining 245 carboxy-terminal residues were not significantly homologous to putative proteins from other members of archaea. Thus, the carboxy-terminal region might be the product of a foreign gene that was incorporated relatively recently into the genome of P. furiosus.

Amino Acid Sequence↗
PubMed2005

Liver transplantation utilizing pediatric cadaver donor livers.

This is a review of a unit's experience with the use of pediatric (up to 15 yr of age), cadaver donor livers for orthotopic liver transplantation (OLTx). The records of 86 patients who underwent 90 OLTx with pediatric donor allografts from January 1986 to September 2002 were reviewed. A total of 69 of 90 (77%) allografts from pediatric donors were used for pediatric (P) recipients, and 21 of 90 (23%) for adult (A) recipients. Donor demographics were: mean donor age 8.5 (0-15) yr; donor sex 53 males/37 females; cause of death head injury 55/90 (61%), cerebral ischaemia 14 of 90 (15%), cerebrovascular 13 of 90 (15%), other eight of 90 (9%). Whole OLTx were performed in 44 of 69 (64%) P group and 20 of 21 (95%) A group. Reduced-size OLTx (13 left lateral lobe, 10 left lobe, one right lobe, one split left lateral lobe) were performed in 25 of 69 (36%) P group vs. in one of 21 (5%) A group, (right lobe split) (p < 0.005). The median follow up was 8.8 yr. The graft loss in the P recipients was 19 of 69 (27.5%) vs. eight of 21 (38.1%) in A recipients. Graft loss for reduced size P OLTx was nine of 25 (36%) vs. 10/44 (22.7%) for whole allograft P OLTx (p = NS). Underlying cause of P graft loss were: chronic rejection six (32%); patient mortality six (32%); vascular four (21%); other three (15%). Underlying cause of A graft loss were: patient mortality four (50%), acute rejection two (25%) and vascular two (25%). OLTx-utilizing pediatric cadaver donor allografts provides acceptable outcomes, including use of reduced-size grafts in pediatric recipients. Vascular complications and chronic rejection tend to be more common in pediatric recipients, whilst patient mortality and graft loss from acute rejection are more common in adult recipients.

Adolescent↗
PubMed2005

Upregulation of transferrin receptor 2 and ferroportin 1 mRNA in the liver of patients with chronic hepatitis C.

BACKGROUND: Iron accumulation has been reported to be associated with progression of liver injury. The mechanism of iron accumulation in the liver is not known. In the present study, hepatic messenger RNA (mRNA) expression of transferrin receptor (TfR)1, TfR2, and ferroportin (FP)1 was measured in patients with chronic hepatitis (CH). METHODS: Eleven patients with CH-B and 43 patients with CH-C were enrolled. All patients underwent liver biopsy. Hepatic expression of TfR1, TfR2 and FP1 mRNA was analyzed using a real-time polymerase chain reaction. Total hepatic iron score (THIS) was evaluated by Prussian blue staining. RESULTS: Serum ferritin concentration is significantly higher in CH-C than in CH-B. Values of THIS of >/=5 were observed only in CH-C patients (44% of CH-C patients). The expression level of TfR2 mRNA was 10-26-fold higher than the TfR1 mRNA expression level. The TfR2 and FP1 mRNA expression was significantly higher in CH-C than in CH-B patients. Hepatic expression of TfR2 and FP1 mRNA was well correlated with THIS. CONCLUSIONS: Hepatic iron accumulation is more severe in patients with CH-C. Upregulation of hepatic iron transporters may contribute to the hepatic iron accumulation in CH-C.

Adult↗
PubMed2005

Molecular characterization of the ZKT gene encoding a protein with PDZ, K-Box, and TPR motifs in Arabidopsis.

The ZKT gene from Arabidopsis encodes a polypeptide of 335 amino acid residues, with a calculated molecular mass of 37.4 kDa. ZKT is a member of a novel protein family present in the plant kingdom, which contains a PDZ, a K-box, and a TPR motif. A BLAST search indicated that the ZKT gene is a single gene in Arabidopsis and that ZKT homologs are present in soybean and rice but not in animals. The level of ZKT mRNA decreased after wounding. Antisera from rabbit immunized with recommbinant ZKT protein recognized a protein of 37 kDa in Arabidopsis. Western analysis with anti-ZKT antibody indicated that the level of ZKT protein does not change after wounding. The ZKT protein has consensus sequence motifs for phosphorylation. Immunoprecipitation with anti-ZKT antibody and western analysis with anti-phosphoamino acid antibody indicated that the ZKT protein is phosophorylated at the threonine and serine residues after wounding. These results suggest that the ZKT protein may act as a molecular adaptor regulated by phosphorylation in wound responses.

Amino Acid Motifs↗
PubMed2005

Polyclonal proliferation of plasma cells associated with marked hypergammaglobulinemia in an elderly patient.

We describe an 89-year-old woman who presented with prominent plasmacytosis mimicking plasma cell leukemia. The apparent serum M-protein level of > 7 g/dL of gamma mobility was revealed to be a polyclonal increase of immunoglobulins. The plasma cells in the peripheral blood expressed polyclonal surface/cytoplasmic immunoglobulins as well as CD19, CD30, CD38, and CD138 antigens but lacked CD10, CD20, CD25, and CD56. The bone marrow plasma cells showed the CD45+, CD19+, CD56-, MPC-1(-/+), and CD49e- immunophenotype, which was in clear contrast with the immunophenotypes of the neoplastic myeloma cells. Abdominal lymphadenopathy, splenomegaly, and a high level of soluble interleukin 2 receptor may have been reflections of an underlying lymphoproliferative disorder, potentially leading to the polyclonal proliferation of plasma cells.

Aged↗
PubMed2005

In vitro study on marginal and internal fit of CAD/CAM all-ceramic crowns.

The purpose of this study was to evaluate the marginal and internal fit of all-ceramic crowns fabricated using the Decsy CAD/CAM system. A master die of maxillary first premolar was measured, and experimental crowns were fabricated. Four conditions were established by combining two convergence angles (4 degrees and 12 degrees) of the abutment with two different luting space settings (15 microm and 55 microm). The results showed that the experimental crowns had a marginal gap of 42 to 56 microm. When the luting space setting was 15 microm, the internal gap was 85-88 microm; when the setting was 55 microm, the internal gap was 126-138 microm. The marginal gap for each experimental crown met the clinically acceptable criterion.

Aluminum Silicates↗
PubMed2005

[A study of attentional resource of discrete and gradational allocation strategy using error-related negativity (ERN)].

The error-related negativity (ERN) is a component of the event-related brain potential (ERP) that is associated with action monitoring and error detection. The ERN amplitude reflects attentional resource allocated to error detection. The present study examined whether discrete or gradational allocation strategy of attentional resource in error detection using the ERN amplitude. Only Eriksen flanker task was used in the single task condition. Eriksen flanker task was used as a primary task and Sternberg memory search task was used as a secondary task in the dual task conditions. The task difficulty of the secondary task manipulated in the present study included the memory load. Memory set sizes of 2, 4 and 6 were used in the Sternberg memory search task (M2, M4 and M6 conditions). The results indicated that reaction time was gradually delayed in the primary task as the task difficulty of the secondary task gradually increased. However the ERN amplitude of the primary task decreased in M6 condition alone. In conclusion, discrete allocation strategy of attentional resource was adopted in the error detection.

Adult↗
PubMed2005

High prevalence of metabolic syndrome among men in Okinawa.

We determined the prevalence of metabolic syndrome (MS) in Okinawa from cross-sectional results of an annual physical checkup. We also calculated the homeostasis model assessment ratio (HOMA-R) as an index of insulin resistance, and examined the relationship between HOMA-R and MS. We studied 3,839 men (mean age 49.2 years) and 3,146 women (mean age 50.0 years), a total of 6,985 people aged from 30 to 79 years, who underwent an annual physical checkup in our hospital between May 2003 and March 2004. The diagnosis of MS was based on the criteria in the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III: ATP III). Abdominal circumference was assessed in accordance with the diagnostic criteria of the Japan Society for the Study of Obesity. The prevalence of MS was 30.2% in men and 10.3% in women. Mean HOMA-R significantly increased with an increase in the number of ATP III risk factors. Logistic regression analysis with the independent variables of sex, age, and HOMA-R gave an odds ratio of MS of 3.6 for men, 1.4 for a 10-year age increment, and 2.0 for an elevation of HOMA-R above 1.0.

Abdominal Fat↗
PubMed2004

Tsukushi functions as an organizer inducer by inhibition of BMP activity in cooperation with chordin.

During chick gastrulation, inhibition of BMP signaling is required for primitive streak formation and induction of Hensen's node. We have identified a unique secreted protein, Tsukushi (TSK), which belongs to the Small Leucine-Rich Proteoglycan (SLRP) family and is expressed in the primitive streak and Hensen's node. Grafts of cells expressing TSK in combination with the middle primitive streak induce an ectopic Hensen's node, while electroporation of TSK siRNA inhibits induction of the node. In Xenopus embryos, TSK can block BMP function and induce a secondary dorsal axis, while it can dorsalize ventral mesoderm and induce neural tissue in embryonic explants. Biochemical analysis shows that TSK binds directly to both BMP and chordin and forms a ternary complex with them. These observations indicate that TSK is an essential dorsalizing factor involved in the induction of Hensen's node.

Amino Acid Sequence↗
PubMed2004

EphA receptor tyrosine kinases interact with co-expressed ephrin-A ligands in cis.

Eph receptor tyrosine kinases have been implicated in various developmental processes, including axonal guidance, angiogenesis and morphogenesis. In general, Eph receptors and their ligands, ephrins, are reciprocally compartmentalized during embryogenesis. However, they are expressed in an overlapping fashion in some developing neural and non-neural tissues. Results from the overexpression or mutant mice of ephrin ligands in the retino-tectal system suggest that ephrin-As regulate co-expressed EphA receptor activity, but little is known about the molecular mechanisms. Here we show that EphA receptors and co-expressed ephrin-A ligands interact directly in cis via their functional binding domains, and that this interaction does not seem to mediate intracellular signals, but has an inhibitory effect on the trans interaction.

Animals↗
PubMed2004

Distinct functions of Rac1 and Cdc42 during axon guidance and growth cone morphogenesis in Drosophila.

Rho family small GTPases are thought to be key molecules in the regulation of cytoskeletal organization, especially for actin filaments. In order to examine the functions of Rac1 and Cdc42 in axon guidance at the midline of the central nervous system in Drosophila embryos, we either activated or inactivated Rac1 and Cdc42 in all postmitotic neurons. We found that the phenotypes of Cdc42 activation and Rac1 inactivation were similar to those of roundabout mutants, in that many extra axons crossed the midline. We also found that Rac1 inactivation is dominant over Roundabout receptor activation. Our observations indicate that Rac1 and Cdc42 have distinct functions in downstream signalling events triggered by Roundabout receptors. In order to further examine the functional difference between Rac1 and Cdc42 in the growth cone morphogenesis, we used primary embryonic cultures to closely observe neurite formation. We showed that activation of Rac1 and Cdc42 has distinct effects on neurite formation, particularly on growth cone morphology and the actin filaments within. Both Rac1 and Cdc42 activation induced large growth cones and long filopodia, but Cdc42 did so more efficiently than Rac1. Only Rac1 activation, however, induced thick actin bundles in the filopodia. We also found a clear difference between Rac1 and Cdc42 in terms of the response to an inhibitor of actin polymerization. Our results suggest that Cdc42 is specifically involved in the regulation of actin filaments in growth cones, whereas Rac1 is involved in additional functions.

Actin Cytoskeleton↗