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Biomedical subjects

Hiroyuki Tanaka

Publications and source records attributed to Hiroyuki Tanaka.

At least 91 records · Page 5Linked to original sources
PubMed2005

Inhibition of IgE-dependent mouse triphasic cutaneous reaction by a boiling water fraction separated from mycelium of Phellinus linteus.

Phellinus linteus, a mushroom, contains constituents that exhibit potent antitumor effects through activating immune cells. Recently, anti-inflammatory and anti-allergic properties of P. linteus extracts have also been implicated. In the present study, therefore, we separated the constituents of mycelium of P. linteus into five fractions-chloroform-soluble (CF), ethyl acetate-soluble (EA), methanol-soluble (AE), water-soluble (WA) and boiling water-soluble (BW) fractions-and examined their suppressive effects on the IgE-dependent mouse triphasic cutaneous reaction. The triphasic reaction was induced in the ear of BALB/c mice passively sensitized with anti-dinitrophenol IgE by painting with 2,4-dinitrofluorobenzene 24 h later. Ear swelling appeared triphasically with peak responses at 1 h, 24 h and 8 days after the challenge. ME, WA and BW given orally at a dose of 100 mg kg significantly inhibited the first and second phase ear swelling, and BW also inhibited the third phase response. CF only inhibited the second phase. The inhibition by BW was the most potent and almost dose-dependent at doses of 30-300 mg kg. BW also inhibited vascular permeability increase caused by passive cutaneous anaphylaxis and histamine, and ear swelling caused by tumor necrosis factor-alpha. In contrast, BW apparently potentiated the production of interleukin-4 and interferon-gamma from anti-CD3-stimulated mouse splenocytes. These results indicate that BW derived from mycelium of P. linteus contains some constituents with anti-allergic as well as immunopotentiating properties.

Journal Article↗
PubMed2005

Comparative studies on the functional roles of N- and C-terminal regions of molluskan and vertebrate troponin-I.

Vertebrate troponin regulates muscle contraction through alternative binding of the C-terminal region of the inhibitory subunit, troponin-I (TnI), to actin or troponin-C (TnC) in a Ca(2+)-dependent manner. To elucidate the molecular mechanisms of this regulation by molluskan troponin, we compared the functional properties of the recombinant fragments of Akazara scallop TnI and rabbit fast skeletal TnI. The C-terminal fragment of Akazara scallop TnI (ATnI(232-292)), which contains the inhibitory region (residues 104-115 of rabbit TnI) and the regulatory TnC-binding site (residues 116-131), bound actin-tropomyosin and inhibited actomyosin-tropomyosin Mg-ATPase. However, it did not interact with TnC, even in the presence of Ca(2+). These results indicated that the mechanism involved in the alternative binding of this region was not observed in molluskan troponin. On the other hand, ATnI(130-252), which contains the structural TnC-binding site (residues 1-30 of rabbit TnI) and the inhibitory region, bound strongly to both actin and TnC. Moreover, the ternary complex consisting of this fragment, troponin-T, and TnC activated the ATPase in a Ca(2+)-dependent manner almost as effectively as intact Akazara scallop troponin. Therefore, Akazara scallop troponin regulates the contraction through the activating mechanisms that involve the region spanning from the structural TnC-binding site to the inhibitory region of TnI. Together with the observation that corresponding rabbit TnI-fragment (RTnI(1-116)) shows similar activating effects, these findings suggest the importance of the TnI N-terminal region not only for maintaining the structural integrity of troponin complex but also for Ca(2+)-dependent activation.

Actins↗
PubMed2005

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is required for branching morphogenesis in the chorioallantoic placenta.

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is a membrane-associated Kunitz-type serine proteinase inhibitor that was initially identified as a potent inhibitor of hepatocyte growth factor activator. HAI-1 is also a cognate inhibitor of matriptase, a membrane-associated serine proteinase. HAI-1 is expressed predominantly in epithelial cells in the human body. Its mRNA is also abundant in human placenta, with HAI-1 specifically expressed by villous cytotrophoblasts. In order to address the precise roles of HAI-1 in vivo, we generated HAI-1 mutant mice by homozygous recombination. Heterozygous HAI-1+/- mice underwent normal organ development. However, homozygous HAI-1-/- mice experienced embryonic lethality which became evident at embryonic day 10.5 postcoitum (E10.5). As early as E9.5, HAI-1-/- embryos showed growth retardation that did not reflect impaired cell proliferation but resulted instead from failed placental development and function. Histological analysis revealed severely impaired formation of the labyrinth layer, in contrast all other placental layers, such as the spongiotrophoblast layer and giant cell layer, which were formed. Our results indicate that mouse HAI-1 is essential for branching morphogenesis in the chorioallantoic placenta and lack of HAI-1 function may result in placental failure.

Animals↗
PubMed2005

Genomic differentiation of Hordeum chilense from H. vulgare as revealed by repetitive and EST sequences.

Hordeum vulgare, cultivated barley, and its wild relative, H. chilense, have several important traits that might be useful for wheat improvement. Here, in situ hybridization and barley expressed sequence tag (EST) markers were used to characterize and compare the chromosomes of H. chilense with those of H. vulgare. FISH with four repetitive DNA sequences, AG, AAG, 5S rDNA and 45S rDNA, was applied to the mitotic chromosomes of H. vulgare, H. chilense and available wheat-H. chilense addition and substitution lines. FISH with the AAG repeat differentiated the individual chromosomes of H. chilense and H. vulgare. The patterns of FISH signals in the two species differed greatly. The 45S rDNA signals were observed on two pairs of chromosomes in both species, while the 5S rDNA signals were observed on four pairs of chromosomes in H. vulgare and on one pair in H. chilense. The AG repeat showed FISH signals at the centromeric regions of all chromosomes of H. vulgare but none of the chromosomes of H. chilense. These results indicate that the chromosomes of the two species are highly differentiated. To study the homoeology between the two species, 209 EST markers of H. vulgare were allocated to individual chromosomes of H. chilense. One hundred and forty of the EST markers were allocated to respective chromosomes of H. chilense using the wheat-H. chilense addition and substitution lines. Twenty-six EST markers on average were allocated to each chromosome except to the chromosome 2H(ch)S, to which only 10 markers were allocated. Ninety percent of the allocated EST markers in H. chilense were placed on H. vulgare chromosomes of the same homo-eologous group, indicating that the expressed sequences of the two species were highly conserved. These EST markers would be useful for detecting chromatin introgressed from these species into the wheat genome.

Chile↗
PubMed2005

Studies of very severe short stature with severe GH deficiency: from the data registered with the foundation for growth science.

The ratio, clinical characteristics, and therapeutic efficacy of hGH treatment in patients with severe short stature (HtSDS below -4SD) with severe GHD (all peak GH values to provocation tests: below 2 mug/L) were studied. From March 1986 to January 1998, 23,110 patients with idiopathic GH deficiency (IGHD) were registered with the Foundation for Growth Science, Japan. These subjects were divided into 5 groups as follows: Group 1 (G1), all subjects; Group 2 (G2), at least one GH peak to provocative test > or = 5 microg/L; Group 3 (G3), 2 microg/L < or = GH peak<5 microg/L; Group 4 (G4), all GH peaks<2 microg/L and HtSDS>-4; Group 5 (G5), all GH peaks<2 microg/L and HtSDS< or = -4. The ratio of G5 was 139 patients (0.6%) out of 23,110 patients with IGHD. In G5, there were no significant differences in birth weight, birth length, gestational age and parental height between G2, G3 and G4. However, asphyxia at delivery was more frequent in G5 and G4 than G2 and G3. Chronological age (CA), bone age (BA) and BA/CA ratio at registration were significantly lower in G5 than G2, G3 and G4. Further, the IGF-I SD score in G5 was significantly lower than those in G2 and G3. After hGH treatment, the final height and final height SDS in G5 remained the lowest, while the DeltaHtSDS value in G5 was the greatest among G2 to G5 groups. In conclusion, the ratio of severe short stature with severe GH deficiency (G5) is only 0.6% of all IGHD cases. Growth failure in G5 seems to occur after birth, and its etiology in G5 seems to be different from that of patients with other forms of IGHD. Early diagnosis and hGH treatment are needed to attain better final height.

Age Determination by Skeleton↗
PubMed2005

Successful treatment of primary cardiac lymphoma with atrioventricular nodal block.

A 69-year-old female suffering from third-degree atrioventricular block with syncope underwent permanent pacemaker implantation. However, she developed shortness of breath 2 months after the implantation. Blood tests revealed elevated levels of LDH, CRP, BNP, and SIL-2R. Transthoracic echocardiography showed thickened left and right atrial walls with mild pericardial effusion. A diagnosis was made based on a CT scan and histology. Although most primary cardiac malignant lymphomas are associated with a poor prognosis, the patient was treated successfully with chemotherapy.

Aged↗
PubMed2005

[Systemic bone diseases; clues for the pathogenetic mechanism of osteoporosis].

Single gene diseases may give us lots of clues to clarify the physiological roles of specific genes in human body. In the case of bone, extensive analysis of the pathogenetic mechanisms of systemic bone diseases may provide new important information on the factors in bone metabolism. In this manuscript, pathogenetic mechanisms of osteoporosis-pseudoglioma syndrome, osteogenesis imperfecta, homocystinuria, lysinuric protein intolerance and Menkes disease will be reviewed in relation to the pathogenesis of osteoporosis.

Bone Diseases↗
PubMed2005

[Bone quality in osteogenesis imperfecta].

Osteogenesis imperfecta is heritable disease that is characterized by bone fragility and low bone mass. The disorder is mainly caused by mutations in either the procollagen type I alpha1 or the procollagen type I alpha2. In general, the mutation in either gene may cause less amount of type I collagen molecule or less integrated type I collagen molecule, low quality. The former is much less severe than the latter. Bisphosphonate treatment improves bone fragility in the disease by the inhibition of increased bone turnover. This may indicates that the beneficial effects of the treatment may due to improvement of the decreased bone mass.

Bone and Bones↗
PubMed2005

Hand circulation after radial artery harvest for coronary artery bypass grafting.

Despite wide spread use of the radial artery (RA) graft for coronary artery bypass grafting, the change of hand circulation after RA harvest has not been fully clarified. Severe hand ischemia such as resting pain or gangrene is a rare complication and has been reported in 4 patients. These cases resulted from occlusive artery disease in forearm, which should be carefully explored before RA harvest. Incidence of mild hand ischemia such as hand claudication or fatigue is unknown, but our study suggested that around 10% of the patients developed mild hand ischemia after RA harvest. The blood flow to the forearm territory was decreased by 20% after RA harvest despite the compensatory dilatation of ulnar artery. The presence of low perfusion in the affected hand has been pointed out in some studies. We reported the decreased tissue oxygenation of the affected hand during hand grip exercise. The Allen test is the most popular preoperative screening method, but is associated with considerable numbers of false-positive and false-negative results. Full length scanning of ulnar artery by ultrasonography seems to have a lower false-positive rate. But further clinical experience is necessary to establish a more reliable screening method.

Coronary Artery Bypass↗
PubMed2005

Endoscopic radial artery harvesting: our initial experience and results of the first 25 patients.

BACKGROUND: The radial artery has become an increasingly popular arterial conduit for coronary artery bypass grafting (CABG). However, the traditional open harvesting technique requires a long incision, and is therefore associated with some wound complications and cosmetic problems. Here, we describe our experience of endoscopic radial artery harvesting (ERAH) through a small incision in 25 patients who underwent CABG. MATERIALS AND METHODS: Between February 2, 2004 and January 7, 2005, a total of 25 patients (4 females; mean age: 64+/-10 years) underwent ERAH using the VasoView System (Guidant Corporation, Indianapolis, IN) at our institution. All patients underwent a preoperative Allen test to assess the competence of the palmer arch. Twenty-four radial arteries were harvested from the nondominant arm and one from the dominant arm. The mean clinical follow-up was 8+/-2.9 months. RESULTS: All radial arteries were harvested through a 2-cm incision at the wrist, successfully removed with ERAH and successfully used as CABG conduits. The mean harvest time was 59+/-11 min, and the mean harvested length was 17+/-1.7 cm. No adjunctive procedures were required during vessel harvesting, and no conversions to the open technique were necessary. Harvesting complications included 2 cases of postoperative hematoma and 7 cases of superficial radial nerve paresthesia. Five postoperative angiographies were performed and all radial arteries were patent. Overall, 24/25 (96%) patients were satisfied with the procedure. CONCLUSION: The ERAH technique was performed as safely as the traditional open technique and the harvested radial arteries were acceptable as CABG conduits. In particular, patient satisfaction with the procedure regarding the cosmetic results was excellent.

Coronary Artery Bypass↗
PubMed2004

Genetics of lagging strand DNA synthesis and maturation in fission yeast: suppression analysis links the Dna2-Cdc24 complex to DNA polymerase delta.

The Cdc24 protein is essential for the completion of chromosomal DNA replication in fission yeast. Although its precise role in this process is unclear, Cdc24 forms a complex with Dna2, a conserved endonuclease-helicase implicated in the removal of the RNA-DNA primer during Okazaki fragment processing. To gain further insights into Cdc24-Dna2 function, we screened for chromosomal suppressors of the temperature-sensitive cdc24-M38 allele and mapped the suppressing mutations into six complementation groups. Two of these mutations defined genes encoding the Pol3 and Cdc27 subunits of DNA polymerase delta. Sequence analysis revealed that all the suppressing mutations in Cdc27 resulted in truncation of the protein and loss of sequences that included the conserved C-terminal PCNA binding motif, previously shown to play an important role in maximizing enzyme processivity in vitro. Deletion of this motif is shown to be sufficient for suppression of both cdc24-M38 and dna2-C2, a temperature-sensitive allele of dna2(+), suggesting that disruption of the interaction between Cdc27 and PCNA renders the activity of the Cdc24-Dna2 complex dispensable.

Alleles↗
PubMed2004

Continuous flow immunosensor for highly selective and real-time detection of sub-ppb levels of 2-hydroxybiphenyl by using surface plasmon resonance imaging.

A biosensor based on surface plasmon resonance (SPR) is developed for the detection of 2-hydroxybiphenyl (HBP). A monoclonal antibody against HBP (abbreviated hereafter as HBP-mAb) is developed and used for the detection of HBP by competitive SPR-based immunoassay and enzyme linked immunosorbent assay (ELISA) methods. A novel HBP-hapten compound, HBP-bovine serum albumin conjugate (HBP-BSA), derived by binding several HBP units with BSA by an aliphatic chain spacer is used in the development of antibody and for the functionalization of immunoprobes. HBP-BSA linked to the Au surface of the SPR sensor chip undergoes inhibitive immunoreaction with HBP-mAb in the presence of free HBP. The SPR-based immunoassay provides a rapid determination (response time: approximately 20 min) of the concentration of HBP in the range of 0.1-1000 ppb (ng/ml). Regeneration of the sensor chip is gained by treating the antibody-anchored SPR sensor chip with a pepsin solution (100 ppm (microg/ml); pH 2.0) for few minutes. The SPR sensor chip is reusable for the detection of HBP for more than 20 cycles with average loss of 0.35% reactivity per regeneration step. HBP concentration is determined as low as 0.1 and 3 ppb using the SPR sensor and ELISA measurements, respectively. The developed SPR sensor for HBP is free from interference by coexisting benzo[a]pyrene (BaP), 2,4-dichlorophenoxyacetic acid (2,4-D) and benz[a]anthracene; SPR angle shift obtained to the flow of HBP is almost same irrespective to the presence or absence of a same concentration of these carcinogenic polycyclic aromatic hydrocarbons together. The SPR sensor for HBP is proved to be applicable in simultaneous detection of HBP and BaP in parallel with another SPR sensor for BaP.

Biosensing Techniques↗