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Biomedical subjects

Y Takagi

Publications and source records attributed to Y Takagi.

At least 19 recordsLinked to original sources
PubMed2006

Inheritance pattern of familial moyamoya disease: autosomal dominant mode and genomic imprinting.

BACKGROUND: Although the aetiology of moyamoya disease (MMD) has not been fully clarified, genetic analysis of familial MMD (F-MMD) has considerable potential to disclose it. OBJECTIVE: To determine the inheritance pattern and clinical characteristics of F-MMD to enable precise genetic analyses of the disease. METHODS: 15 highly aggregated Japanese families (52 patients; 38 women and 14 men) with three or more affected members were examined. The difference in categories of age at onset (child onset, adult onset and asymptomatic) between paternal and maternal transmission was compared by chi2 statistics. RESULTS: In all families there had been three or more generations without consanguinity, and all types of transmission, including father-to-son, were observed. Among a total of 135 offspring of affected people, 59 (43.7%) were patients with MMD or obligatory carriers. Affected mothers were more likely to produce late-onset (adult-onset or asymptomatic) female offspring (p = 0.007). CONCLUSIONS: The mode of inheritance of F-MMD is autosomal dominant with incomplete penetrance. Thus, in future genetic studies on F-MMD, parametric linkage analyses using large families with an autosomal dominant mode of inheritance are recommended. Genomic imprinting may be associated with the disease.

Adolescent↗
PubMed2006

Near-infrared spectral results of asteroid Itokawa from the Hayabusa spacecraft.

The near-infrared spectrometer on board the Japanese Hayabusa spacecraft found a variation of more than 10% in albedo and absorption band depth in the surface reflectance of asteroid 25143 Itokawa. Spectral shape over the 1-micrometer absorption band indicates that the surface of this body has an olivine-rich mineral assemblage potentially similar to that of LL5 or LL6 chondrites. Diversity in the physical condition of Itokawa's surface appears to be larger than for other S-type asteroids previously explored by spacecraft, such as 433 Eros.

Journal Article↗
PubMed2006

Touchdown of the Hayabusa spacecraft at the Muses Sea on Itokawa.

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

Journal Article↗
PubMed2006

Combination chemotherapy with docetaxel and nedaplatin for recurrent esophageal cancer in an outpatient setting.

The purpose of this study was to address the feasibility of combination chemotherapy of docetaxel and nedaplatin for recurrent esophageal cancer patients in an outpatient setting. Patients received docetaxel (30 mg/m(2) intravenously) on day 1 and nedaplatin (40 mg/m(2) intravenously) on day 1 every 2 weeks. In total, 28 patients with recurrent esophageal cancer after the initial treatment (esophagectomy, chemotherapy and/or chemoradiotherapy) were enrolled. Each patient received six cycles of treatment and was evaluated with a computed tomography scan. The percentage of patients who completed this therapy was 60.7%. Complete response and partial response were achieved by 3.6% and 35.7% of patients, respectively. The most frequent toxicities were leukopenia and anemia; non-hematological toxicities were generally mild. There was no treatment-related death. The median survival time and 1-year survival rate were 8.5 months and 15.9%, respectively. This outpatient combination chemotherapy was useful as second-line chemotherapy for recurrent esophageal cancer.

Aged↗
PubMed2006

[Extracorporeal membrane oxygenation for severe respiratory failure during thoracic aortic aneurysm repair].

We present a case of successful management for severe respiratory failure during thoracic aortic aneurysm repair by applying extracorporeal membrane oxygenation (ECMO). The patient was a 71-year-old man who was diagnosed as thoracic aortic aneurysm and coronary artery stenosis. Severe respiratory failure occurred during operation because of pulmonary hemorrhage, and it was difficult to wean from cardiopulmonary bypass. ECMO was provided for improvement of oxygenation and CO2 removal. Pulmonary hemorrhage was controlled by strict management of coagulation system, and ECMO was discontinued after improvement of oxygenation on the 4th postoperative day. It is considered that early application of ECMO was effective in this case.

Aged↗
PubMed2004

Coupling between phosphate release and force generation in muscle actomyosin.

Energetic, kinetic and oxygen exchange experiments in the mid-1980s and early 1990s suggested that phosphate (Pi) release from actomyosin-adenosine diphosphate Pi (AM.ADP.Pi) in muscle fibres is linked to force generation and that Pi release is reversible. The transition leading to the force-generating state and subsequent Pi release were hypothesized to be separate, but closely linked steps. Pi shortens single force-generating actomyosin interactions in an isometric optical clamp only if the conditions enable them to last 20-40 ms, enough time for Pi to dissociate. Until 2003, the available crystal forms of myosin suggested a rigid coupling between movement of switch II and tilting of the lever arm to generate force, but they did not explain the reciprocal affinity myosin has for actin and nucleotides. Newer crystal forms and other structural data suggest that closing of the actin-binding cleft opens switch I (presumably decreasing nucleotide affinity). These data are all consistent with the order of events suggested before: myosin.ADP.Pi binds weakly, then strongly to actin, generating force. Then Pi dissociates, possibly further increasing force or sliding.

Actins↗
PubMed2004

Drug-incorporating calcium carbonate nanoparticles for a new delivery system.

We devised a simple method for incorporating drugs into solid calcium carbonate nanoparticles (nano-CaCO3). The size of nano-CaCO3 was controlled by mixing speed. Washing the nanoparticles released little incorporated drug but much drug that was adsorbed on the surface. In an in vitro releasing test, granulocyte colony-stimulating factor incorporated in nano-CaCO3 was chemically stable and released very slowly. Subcutaneous injection of nano-CaCO3 incorporating betamethasone phosphate (BP) resulted in a smaller initial increase in plasma concentration and a subsequent sustained release in compared with betamethasone phosphate solution. Nano-CaCO3 may be useful to deliver hydrophilic drugs and bioactive proteins.

Animals↗
PubMed2004

The transcriptional program of synchronous gametogenesis in Chlamydomonas reinhardtii.

Cells of Chlamydomonas reinhardtii undergo gametogenesis to produce sexually competent gametes under nitrogen-starved conditions. By using a synchronized system for gametogenesis of early G1 cells, several previously identified marker genes and 18 novel nitrogen-starved gametogenesis (NSG) genes isolated by macroarray analysis were placed into at least three temporal classes of expression. Early genes are induced transiently in the first 2 h after transfer to nitrogen-free medium. Middle genes are strongly induced between 3 h and 4 h after nitrogen removal, a time corresponding to the acquisition of mating competency, suggesting their involvement in the gamete program. Late genes are induced between 5 h and 8 h after nitrogen removal, a time after the completion of gametic differentiation, suggesting that they are not directly involved in the formation of sexually competent gametes. All of the 18 NSG genes examined are induced in both mating-type plus and minus gametes and about two-thirds of the genes are also expressed in the mitotic cell cycle, especially at S/M phases.

Animals↗
PubMed2004

Immunocompetent cells in the pulp of human deciduous teeth.

This immunohistological study sought to determine how the distribution and density of various immunocompetent cells change in the pulp of human deciduous teeth during the process of physiological root resorption. Forty-three extracted deciduous teeth at various stages of resorption were subjected to immunoperoxidase staining with the use of antibodies directed to HLA-DR, CD68, factor XIIIa and lymphocyte subsets. In intact deciduous teeth (group 0), all types of cells examined, except for CD20+ B lymphocytes, were detected. In teeth in which resorption was less than 1/3 of the root length (group 1), all types of cells showed a statistically significant increase compared with group 0 (P<0.05; Mann-Whitney's U-test). HLA-DR+, CD68+, and factor XIIIa+ cells with a dendritic profile kept their distribution in the periphery of the pulp, and oval and round, newly recruited macrophages accumulated in the central portion of the pulp and near the resorption sites. In teeth where resorption was 1/2 to 2/3 (group 2), all the cell types increased further. Aggregations of HLA-DR+, CD68+, and factor XIIIa+ cells were frequently seen in the central portion of the pulp, and T and B lymphocytes occasionally formed some clusters. Comparisons with group 1 revealed that the density of these cells, except for CD20+ cells, showed significant increases (P<0.05; Mann-Whitney's U-test). These results provided evidence showing that immunocompetent cells of deciduous tooth pulp increase with the progress of physiological root resorption, suggesting that immunocompetency of deciduous teeth is altered by this process.

Analysis of Variance↗
PubMed2004

Presence of staphylococcal exfoliative toxin A in sera of patients with atopic dermatitis.

BACKGROUND: It has been reported that the toxins that Staphylococcus aureus produces are associated with the exacerbation of atopic dermatitis (AD). It has been shown in many studies that staphylococcal enterotoxin (SE) A and SEB contribute to AD by humoral immunity through IgE production as a superantigen. On the other hand, little attention has been paid to the relationship between AD and exfoliative toxin x (ETx). OBJECTIVE: We investigated the toxins that are frequently detected from the skin of patients and how these toxins affect AD. METHODS: S. aureus, isolated from the skin of 100 patients with mild to severe AD, were examined for the producibility of toxins by polymerase chain reaction. Serum samples were obtained from 21 patients with mild and moderate AD. The levels of SEB, ETA, total IgE, specific IgE, and specific IgG in sera were measured by ELISA. RESULTS: SEB was most frequently detected from S. aureus on the skin of these patients as previously reported. And ETx, to which little attention has been paid so far, was frequently detected next to SEB. Furthermore, ETA was detected from the sera of almost all the AD patients. SEB was not detected at all. Although the level of ETA in the AD group was significantly higher than that of controls, ETA-specific IgE was not detected from their sera. High levels of ETA tended to be detected from infantile patients. Although there were no significant differences in the levels of ETA-IgG between AD and the controls, its prevalence was more than twice as high as the controls in AD. CONCLUSION: These results suggest that many AD patients were exposed to ETx. We conclude that ETx may contribute to exacerbation of AD, particularly in infants, by a mechanism that is not through specific IgE production, unlike SEB.

Adolescent↗
PubMed2004

[Subpectoral implantable cardioverter defibrillator implantation in a 20 kg-weighted child].

An 11-year-old boy (weight 20 kg, height 124 cm), who was survived from ventricular fibrillation due to hypertrophic cardiomyopathy, admitted to our institution for implantable cardioveter defibrillator (ICD) implantation. We implanted a transvenous single coil lead and a device (Medtronic model 6943, GEM II VR 7229 Cx) in the subpectoral pocket. We selected this system because of less restriction on normal cardiac function, low operative morbidity, and expectation of long-term defibrillation threshold stability. Subpectoral implantation is cosmetically acceptable comparing with abdominal area. Lead insertion by cut-down technique is feasible and recommended to avoid lead-related complications. ICDs are infrequently used in pediatric patients and prospective study with long-term follow-up will be required to ascertain the prognosis for young survivors from sudden cardiac death.

Body Weight↗
PubMed2004

Repeated administration of cytokines improve the ex-vivo generation of human dendritic cells.

The in vitro generation of dendritic cells (DCs) enables us to practice antitumor immune therapy. Peripheral monocytes can differentiate to DCs in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4) in vitro. To generate a large number of DCs, we compared the number of DCs generated from leukapheresis products to those from conventional blood samplings in healthy volunteers. The induction rates of the DCs were equal for these two blood samplings, and 10(7) DCs were obtainable from one leukapheresis product. In contrast, the number of DCs varied significantly depending on the individual (30-50% in good responders vs. less than 10% in poor responders). DCs appeared as aggregates of indented cells during culture in good responders, while large cells were floating sparsely in poor responders. Repeated administration of GM-CSF and IL-4 improved the yields of DCs and induced proliferation of autologous lymphocytes in poor responders. As a prototype of cell therapy, the generation of DCs will require a titration of differentiation processes, depending on each individual's responsiveness to cytokines.

Antigens, CD↗
PubMed2003

Improvement of rice (Oryza sativa L.) seed oil quality through introduction of a soybean microsomal omega-3 fatty acid desaturase gene.

Microsomal omega-3 fatty acid desaturase is an essential enzyme in the production of the n-3 polyunsaturated fatty acid alpha-linolenic acid during the seed developing stage. We have constructed a chimeric gene consisting of a maize Ubi1-P-int and a soybean GmFAD3 cDNA, which was introduced into rice plants by Agrobacterium-mediated transformation. Ten transformants containing the chimeric gene were established and expression subsequently confirmed by Northern blotting. Furthermore, alpha-linolenic acid content of the T(1) seeds increased dramatically up to tenfold that of the control, and this phenotype was also stably inherited in the T(2) and T(3) progenies. These results demonstrate that the alpha-linolenic acid content of rice seed oil can easily be altered using the combination of a high-activity promoter and a GmFAD3 gene.

Blotting, Northern↗
PubMed2002

Localization of cathepsin K in bovine odontoclasts during deciduous tooth resorption.

Cathepsin K is a cysteine proteinase, which is abundantly and selectively expressed in osteoclasts. It is believed to play an important role in the proteolysis of bone resorption by osteoclasts. The objectives of this study were to investigate the association of cathepsin K in the physiological root resorption of deciduous teeth and to identify the cathepsin K-producing cells in deciduous root resorption. RT-PCR and Northern blot analysis of the total RNAs extracted from bovine active and resting root-resorbing tissues, which lie between the root of deciduous tooth and its permanent successor, were performed. The active root-resorbing tissue, which has a high population of odontoclasts on its surface that is attached to resorbing root surface, showed an extremely high expression of cathepsin K in comparison with the resting root-resorbing tissue. By in situ hybridization, cathepsin K mRNA was highly and selectively expressed in multinucleated odontoclasts that aligned along the surface of the tissue and apposed to the resorbing root surface of the deciduous tooth. Western blot analysis of the active root-resorbing tissue was used to characterize the anti-cathepsin K antibody. A band of 27 kDa, corresponding with the predicted size for mature cathepsin K, was demonstrated. Immunohistochemistry confirmed the specific localization of cathepsin K protein to the odontoclasts. These results demonstrate that odontoclasts in the deciduous root resorption express cathepsin K mRNA and protein that may participate in the proteolysis of root resorption of the deciduous tooth.

Animals↗
PubMed2002

Expression of matrix metalloproteinase-9 mRNA and protein during deciduous tooth resorption in bovine odontoclasts.

Matrix metalloproteinase-9 (MMP-9, or gelatinase B) is an extracellular proteinase that is highly expressed in osteoclasts and has been postulated to play an important role in their resorptive activity. Although MMP-9 has been reported to play a role in bone resorption, the association of this enzyme during deciduous tooth resorption has not yet been clarified. The purpose of the present study was to increase our understanding of the role of MMP-9 during deciduous tooth resorption. Reverse transcription-polymerase chain reaction (RT-PCR) and northern blot analysis of total RNAs extracted from bovine root-resorbing tissues, which lie between the root of a deciduous tooth and its permanent successor, revealed the expression of mRNA for MMP-9 in the tissue. These results indicate that MMP-9 may be involved in the process of deciduous tooth resorption. In addition, in situ hybridization and immunohistochemistry were also performed to identify the cells that produced MMP-9 in bovine root-resorbing tissue. MMP-9 mRNA was highly expressed in odontoclasts that were aligned along the surface of the tissue. Immunohistochemistry confirmed the predominant localization of MMP-9 in odontoclasts. The present data demonstrate that odontoclasts in deciduous root resorption express MMP-9, which may participate in proteolysis during root resorption of deciduous tooth.

Animals↗
PubMed2002

Mechanism of action of hammerhead ribozymes and their applications in vivo: rapid identification of functional genes in the post-genome era by novel hybrid ribozyme libraries.

A hammerhead ribozyme was demonstrated to be a metalloenzyme. By controlling the metal-binding ability of the hammerhead ribozyme in the presence or absence of a specific sequence of interest, we engineered an allosterically controllable ribozyme, designated the maxizyme. Hybrid ribozymes were then constructed by coupling the site-specific cleavage activity of a hammerhead ribozyme with the unwinding activity of an endogenous RNA helicase. This leads to extremely efficient cleavage of target mRNA, not only in vitro, but also in vivo, and eliminates one of the major problems arising in the application of ribozymes for cleavage of mRNA in vivo : that many target sites on the RNA were previously inaccessible to cleavage owing to secondary and/or tertiary structure formation. Since hybrid ribozymes can efficiently attack target sites within mRNA, libraries were made of hybrid ribozymes with randomized binding arms, which were then introduced into cells. This procedure made it possible to readily identify the relevant genes associated with a specific phenotype, such as in apoptosis and cancer metastasis pathways. This application of a randomized library of hybrid ribozymes represents a simple, yet powerful, method for the identification of genes associated with specific phenotypes in the post-genome era. Moreover, vector-based siRNA (short-interfering RNA for RNA interference, RNAi) can also be used for the creation of the libraries and for the subsequent confirmation of the identified genes, relevant in the examined phenotype.

Gene Expression Profiling↗
PubMed2002

Cell cycle-regulated factors in esophageal cancer.

Alterations of cell cycle-regulated genes play an important role in the process of carcinogenesis, and some of them are thought to be prognostic factors in esophageal cancer. The expressions of p53, p16, pRB and Cyclin D1 proteins were evaluated immunohistochemically in 144 patients who underwent curative esophagectomy without any adjuvant therapy before surgery. p53 overexpression was observed in 99 (69%) out of the 144 patients. No significant correlation was noted between p53 and any other gene expression. p16 expression was observed in 12 (8.3%) out of all cases. A negative correlation was recognized between p16 and Cyclin D1 expression (P=0.0004). pRB expression was observed in 130 (90.3%) out of all cases, whereas pRB expression was not observed in 11 out of the 12 patients with p16-positive tumors. A negative correlation was also found between p16 and pRB (P < 0.0001). A positive correlation was noted between pRB and Cyclin D1 expression (P=0.0009). The cumulative survival rate of patients without pRB expression was significantly lower than that of patients with positive expression (P=0.003). In the multivariate survival analysis, pRB expression was an independent prognostic factor. In 98% of all patients with esophageal cancer, impairment of the G1 checkpoint is due to a loss of function by p16, pRB or Cyclin D1, which showed a negative correlation in each factor. In addition, aberrant expression of pRB is useful as a prognostic factor in esophageal cancer.

Adult↗