Biomedical subjects

Y Takami

Publications and source records attributed to Y Takami.

At least 19 recordsLinked to original sources

PubMed2005

Attenuation of acid induced oesophagitis in VR-1 deficient mice.

BACKGROUND AND AIMS: Activation of the vanilloid receptor subtype 1 (VR-1) results in release of proinflammatory peptides which initiate an inflammatory cascade known as neurogenic inflammation. We investigated its role in an acute model of surgically induced oesophagitis. METHODS: Oesophagitis was induced by pyloric ligation in wild-type and VR-1 deficient mice. A subset of animals were administered the VR-1 antagonist capsazepine, famotidine, or omeprazole one hour before surgery. Five hours after surgery, myeloperoxidase activity (MPO), histological damage scores, intragastric pH, and immunocytochemical analysis of substance P (SP) receptor endocytosis were determined. RESULTS: Oesophagitis induced knockout mice exhibited significantly lower levels of MPO activity, histological damage scores, and SP receptor endocytosis than wild-type mice. Inflammatory parameters were significantly reduced by acid inhibition and capsazepine in wild-type mice. CONCLUSIONS: We conclude that acute acid induced oesophagitis is reduced in animals lacking VR-1. This suggests that acid induced oesophagitis may act through VR-1 and that inhibition of the receptor may reduce inflammation.

Acute Disease↗

PubMed2005

Species status and phylogeography of two closely related Coptolabrus species (Coleoptera: Carabidae) in South Korea inferred from mitochondrial and nuclear gene sequences.

We investigated the species status and intraspecific phylogeography in South Korea of two ground beetle species, Coptolabrus jankowskii and Coptolabrus smaragdinus (Coleoptera: Carabidae), using statistical parsimony networks and nested clade analyses based on sequences from the mitochondrial cytochrome oxidase subunit I (COI) and nuclear phosphoenolpyruvate carboxykinase (PepCK) and wingless (Wg) genes. Although traditional parsimony tree construction generally failed to resolve interspecific relationships and construct biologically meaningful genealogies, analysis using statistical parsimony networks yielded statistically significant inter- and intraspecific genealogical structures. We found that although these two species represent a notable case of trans-species polymorphisms in both mitochondrial and nuclear gene sequences, their status as separate species was evidenced by the nonrandom association between species and nested clades at various nesting levels. The exceptional occurrence of shared identical or very similar COI sequences was considered to be the result of introgressive hybridization. In addition, range expansion and fragmentation events across the Korean Peninsula and adjacent islands were inferred from nested clade phylogeographical analyses. The COI gene revealed the geographical divergence of major eastern and western clades and historical biogeographical events within each major clade, whereas the nuclear PepCK gene, which did not reveal corresponding east-west clades, indicated past fragmentation and range expansion across wide areas that may have been the result of older biogeographical events. Thus, phylogeographical inferences drawn from analyses of mitochondrial and nuclear genes can reveal different and potentially complementary information about phylogeographical processes.

Animals↗

PubMed2001

Activation of Cdh1-dependent APC is required for G1 cell cycle arrest and DNA damage-induced G2 checkpoint in vertebrate cells.

Anaphase-promoting complex (APC) is activated by two regulatory proteins, Cdc20 and Cdh1. In yeast and Drosophila, Cdh1-dependent APC (Cdh1-APC) activity targets mitotic cyclins from the end of mitosis to the G1 phase. To investigate the function of Cdh1 in vertebrate cells, we generated clones of chicken DT40 cells disrupted in their Cdh1 loci. Cdh1 was dispensable for viability and cell cycle progression. However, similarly to yeast and Drosophila, loss of Cdh1 induced unscheduled accumulation of mitotic cyclins in G1, resulting in abrogation of G1 arrest caused by treatment with rapamycin, an inducer of p27(Kip1). Further more, we found that Cdh1(-/-) cells fail to maintain DNA damage-induced G2 arrest and that Cdh1-APC is activated by X-irradiation-induced DNA damage. Thus, activation of Cdh1-APC plays a crucial role in both cdk inhibitor-dependent G1 arrest and DNA damage-induced G2 arrest.

Anaphase-Promoting Complex-Cyclosome↗

PubMed2001

Leucine zipper motif of chicken histone acetyltransferase-1 is essential for in vivo and in vitro interactions with the p48 subunit of chicken chromatin assembly factor-1.

We cloned cDNA encoding chicken cytoplasmic histone acetyltransferase-1, chHAT-1, comprising 408 amino acids including a putative initiation Met. It exhibits 80.4% identity to the human homolog and possesses a typical leucine zipper motif. The glutathione S:-transferase (GST) pull-down assay, involving truncated and missense mutants of the chicken chromatin assembly factor-1 (chCAF-1)p48, revealed not only that a region (comprising amino acids 376-405 of chCAF-1p48 and containing the seventh WD dipeptide motif) binds to chHAT-1 in vitro, but also that mutation of the motif has no influence on the in vitro interaction. The GST pull-down assay, involving truncated and missense chHAT-1 mutants, established that a region, comprising amino acids 380-408 of chHAT-1 and containing the leucine zipper motif, is required for its in vitro interaction with chCAF-1p48. In addition, mutation of each of four Leu residues in the leucine zipper motif prevents the in vitro interaction. The yeast two-hybrid assay revealed that all four Leu residues within the leucine zipper motif of chHAT-1 are necessary for its in vivo interaction with chCAF-1p48. These results indicate not only that the proper leucine zipper motif of chHAT-1 is essential for its interaction with chCAF-1p48, but also that the propeller structure of chCAF-1p48 expected to act as a platform for protein-protein interactions may not be necessary for this interaction of chHAT-1.

Acetyltransferases↗

PubMed2001

Resolution of perivalvular hematoma of the Freestyle stentless aortic root bioprosthesis implanted with a subcoronary technique.

The modified subcoronary technique is frequently used to implant the Freestyle aortic root bioprosthesis because of its ease. This technique is primarily associated with hematoma in the potential space between the prosthetic and native aortic walls. We report a case of resolution of perivalvular hematoma around the Freestyle valve 6 months after implantation in a patient with aneurysm of the noncoronary sinus of Valsalva. During follow-up, the patient underwent no significant changes in pressure gradient or degree of regurgitation. Although long-term results are not yet known, the subcoronary technique may be a feasible alternative for patients with aneurysms in the sinus of Valsalva to exclude it, unless the sinotubular junction and aortic annulus are intact.

Aged↗

PubMed2001

A monoclonal antibody against insect CALNUC recognizes the prooncoprotein EWS specifically in mammalian cells. Immunohistochemical and biochemical studies of the antigen in rat tissues.

A monoclonal antibody against insect CALNUC was shown to recognize an 85-kDa nuclear protein specifically in mammalian cells. Amino acid sequencing of the protein purified from rat liver revealed it to be EWS, a prooncoprotein for Ewing sarcomas and related tumors. Using the antibody, distribution of EWS was studied in rat tissues fixed with 4% paraformaldehyde by immunohistochemical methods. On thaw-fixed cryosections or those of perfusion-fixed tissues, almost all cell nuclei showed the specific staining. In immersion-fixed tissues, the staining unexpectedly disappeared in particular tissues (kidney cortex, liver, etc.), although it was recovered by autoclaving the cryosections. Western blotting also demonstrated the ubiquitous expression of EWS in the tissues. In extracts from the liver, the 85-kDa band rapidly disappeared in a Ca(2+)-dependent manner, but never in the testis. The antigen was very labile in kidney homogenates even without Ca2+. Biochemical studies with digoxigenin-labeled EWS showed that the Ca(2+)-dependent disappearance was associated with upward mobility shifts of EWS. These suggested that EWS was ubiquitously expressed in rat tissues, and that the antigen was masked in particular tissues during the immersion fixation.

Animals↗

PubMed2001

The "mini-elephant trunk" technique of distal anastomosis in total arch replacement through a median sternotomy for a distal aortic arch aneurysm.

A median sternotomy is considered to have several advantages over a left thoracotomy as a route for the surgical treatment of a distal aortic arch aneurysm, including less pain and less lung damage. In a median sternotomy, distal anastomosis is such an important problem that we herein present a useful technique to prevent surgical bleeding from it. An invaginated 40-mm-long graft is inserted into the distal aorta, sutured to the aortic wall, unfolded, and anastomosed with a four-limbed tube graft. We applied this "mini-elephant trunk" technique to total arch replacement for both a saccural distal aneurysm, where the distal aorta was transected, and a fusiform aneurysm, where the invaginated graft was sutured by the "inclusion" method. This technique enables a greater surface contact area between the graft and the aortic wall at the distal anastomosis, thus resulting in a reduced risk of bleeding.

Aged↗

PubMed2001

Relation of intraoperative flow measurement with postoperative quantitative angiographic assessment of coronary artery bypass grafting.

BACKGROUND: It is critical to evaluate the anastomotic quality of coronary artery bypass grafting (CABG) in the operating room. The aim of this study is to determine the validity of intraoperative flow measurement for predicting the quality of CABG by comparison with the postoperative quantitative angiographic evaluation of the grafts. METHODS: Eighty-two grafts, including 37 internal thoracic arteries, were examined intraoperatively with a transit-time flowmeter. Coronary angiograms were performed 14 +/- 5 days after CABG to quantify the diameters at the toe, heel, and anastomosis proper of the grafts. RESULTS: There were significant differences between patent and nonpatent grafts in all intraoperative flow parameters. However, the only cut-off value to distinguish patent from nonpatent was a fast Fourier transformation (FFT) ratio of 1.0. FFT is the ratio of powers of the fundamental frequency and its first harmonic. Postoperative quantitative angiography indicated that the stenosis was greatest at the heel of the anastomosis. The degree of stenosis at the heel of the anastomosis alone correlated significantly with intraoperative mean flow values. CONCLUSIONS: Fast Fourier transformation analysis of flow measurement may be useful to differentiate patent grafts intraoperatively. Intraoperative flow measurement may predict the most stenotic part of the anastomosis.

Aged↗

PubMed2001

A simple method to determine anastomotic quality of coronary artery bypass grafting in the operating room.

Anastomotic quality of coronary artery bypass grafting is directly associated with peri-operative and long-term clinical results. In this study, we investigated a cut-off value for intra-operative flow measurement. This value could be of use to a surgeon in determining the anastomotic quality of grafts. Intra-operative transit-time flow variables (mean flow, pulsatility index, % efficiency, fast Fourier transformation (FFT) of the flow curve) and the 2-week post-operative angiographic findings were examined in 66 coronary artery bypass grafts, including 33 internal thoracic arteries. There were significant differences between patent and non patent grafts in all of the intra-operative flow parameters. Only the FFT ratio, the ratio of powers of the fundamental frequency and its first harmonic, could be utilized as a cut-off value to distinguish patent from non patent grafts. All stenotic or occluded grafts showed an intra-operative FFT ratio of <1.0, while all patent grafts yielded a ratio of >1.0. Based upon these results, we concluded that power spectral analysis of flow measurement might be useful for intra-operative differential diagnosis of the anastomotic quality in coronary artery bypass grafting.

Aged↗

PubMed2001

Participation of histones and histone-modifying enzymes in cell functions through alterations in chromatin structure.

Alterations in the chromatin structure are preferentially involved in the regulation of cell functions, including gene expression, in eukaryotes. Three types of mechanisms, by which the alterations are caused have been reported: (i) variants of histone subtypes, (ii) chromatin remodeling, and (iii) post-translational modification. This review focuses mainly on the first and third mechanisms, especially on the acetylation of core histones, one of the third mechanisms. Using the gene targeting technique for the DT40 chicken B cell line, we systematically generated a number of mutants, respectively, devoid of particular genes encoding histones and histone deacetylase(s) (HDACs). Most of the H1 and core histone variants should be involved positively or negatively in the transcription regulation of particular genes. Of the chicken HDACs (chHDACs), chHDAC-2 controls the amount of the IgM H-chain at the steps of both transcription and alternative pre-mRNA processing, and chHDAC-3 is essential for cell viability, whereas chHDAC-1 merely affects gene expression in DT40 cells. These results indicate that HDAC family members should participate, in combination with one another, and/or histone acetyltransferase(s) (HATs), in the acetylation of core histones that regulates gene expression through alterations in the chromatin structure.

Acetyltransferases↗

PubMed2000

Distinct regions of the chicken p46 polypeptide are required for its in vitro interaction with histones H2B and H4 and histone acetyltransferase-1.

We cloned cDNA encoding the chicken p46 polypeptide, chp46, homologous to the p48 subunit of chicken chromatin assembly factor-1, chCAF-1p48. It comprises 424 amino acids including a putative initiation Met, is a member of the WD protein family, with seven WD repeat motifs, and exhibits 90.3% identity to chCAF-1p48 and 94.3% identity to the human and mouse p46 polypeptides (hup46 and mop46). The in vitro immunoprecipitation experiment established that chp46 interacts with histones H2B and H4 and chicken histone acetyltransferase-1, chHAT-1, whereas hup46 interacts with histones H2A and H4 and chHAT-1 and chCAF-1p48 with histone H4 and chHAT-1. The in vitro immunoprecipitation experiment, involving truncated mutants of chp46, revealed not only that two regions comprising amino acids 33-179 and 375-404 are necessary for its binding to H2B, but also that two regions comprising amino acids 1-32 and 405-424 are necessary for its binding to H4. Furthermore, the GST pulldown affinity assay, involving truncated mutants of chp46, revealed that a region comprising amino acids 359-404 (in fact, 375-404) binds to chHAT-1 in vitro. Taken together, these results indicate not only that chp46 should participate differentially in a number of DNA-utilizing processes through interactions of its distinct regions with chHAT-1 and histones H2B and H4, but also that the proper propeller structure of chp46 is not necessary for its interaction with chHAT-1.

Acetyltransferases↗

PubMed2000

N-terminal region, C-terminal region, nuclear export signal, and deacetylation activity of histone deacetylase-3 are essential for the viability of the DT40 chicken B cell line.

Histone deacetylases (HDACs) are involved in the deacetylation of core histones, which is related to transcription regulation in eukaryotes through alterations in the chromatin structure. We cloned cDNA and genomic DNA encoding a chicken HDAC, chHDAC-3, which was localized in both the nuclei and cytoplasm in DT40 cells. Although one of the two chHDAC-3 alleles could be disrupted with high efficiency, no homozygous mutants were obtained after a second round of the gene-targeting technique due to its necessity for DT40 cells. We introduced a chHDAC-3 transgene under the control of a tetracycline-responsive promoter into the heterozygous mutant and subsequently disrupted the remaining endogenous chHDAC-3 allele to generate the homozygous chHDAC-3-deficient mutant, DeltachHDAC-3/FHDAC3. Inhibition of the expression of the regulatable chHDAC-3 transgene caused apoptotic cell death of the mutant. Complementation experiments involving truncated and missense chHDAC-3 mutant proteins revealed that the 1-23 N-terminal sequence, the 389-417 C-terminal sequence, the nuclear export signal, and the deacetylation activity of chHDAC-3 were essential for the cell viability. Taken together, these results indicate that chHDAC-3 plays an essential role, probably as a scavenger in the cytoplasm, in the proliferation of DT40 cells.

Amino Acid Sequence↗

PubMed2000

Histone H1 variants play individual roles in transcription regulation in the DT40 chicken B cell line.

Thirty-nine of the 44 chicken histone genes are located in a major gene cluster of 110 kb, the others being distributed in four separate regions. All 6 H1 genes, which are present in the cluster and encode different variants, are expressed in the DT40 chicken B cell line, at levels ranging from about 5 to 40%. To clarify differences in the natures of these H1 variants, using gene-targeting techniques, we generated a series of DT40 mutants, which are devoid of each of the 5 H1 genes, respectively. Analyses of six H1-deficient mutants, comprising the latter five and a previously generated H1-deficient mutant, revealed that the protein patterns on 2D-PAGE were definitely different from each other, indicating that each H1 variant plays an individual role in the transcription regulation of specific genes in DT40 cells.

Alleles↗

PubMed2000

Small-cell carcinoma of the gallbladder: report of a case.

We report herein the case of an 81-year-old woman in whom a mass in the gallbladder was revealed by an ultrasound examination conducted as part of a follow-up study for a silent gallstone. The mass showed evidence of invasion into the adjacent liver parenchyma. Under the tentative diagnosis of malignant neoplastic disease originating in the gallbladder, a cholecystectomy with partial hepatectomy was performed. Histological examination of the tumor confirmed a diagnosis of small-cell carcinoma of the gallbladder, which is considered to be a rare type of neoplasm.

Aged↗

PubMed2000

Magnesium and fluoride distribution in human cementum with age.

Sixty-two human teeth, obtained from subjects aged 11 to 80 years, were used to determine the magnesium and fluoride concentration and distribution with age in human cementum. Transverse sections were prepared from the root region of teeth. Samples, each 30 microm thick, were abraded in sequence from the cementum surface and the cemento-dentine junction by an abrasive micro-sampling technique. Magnesium concentrations were lower in the cementum surface, and increased towards the cemento-dentine junction (CDJ), while fluoride concentrations were higher in cementum surfaces and tended to decrease towards CDJ. Fluoride distribution patterns were similar to that reported earlier while average fluoride concentration increased with age, however, either no change or decreasing tendencies were observed with magnesium.

Adolescent↗

PubMed2000

Theoretical analysis of right gastroepiploic artery grafting to right coronary artery.

BACKGROUND: The right gastroepiploic artery (GEA) has been used as the second reliable arterial graft for coronary artery bypass grafting (CABG). However, concern regarding the flow competition with the recipient coronary artery has remained. METHODS: An application of in situ GEA grafting to the right coronary artery (RCA) was studied by using a theoretical model. The theoretical model of CABG was given variables; ie, the diameters and the lengths of both in situ GEA and proximal segment of the RCA, and the degree of proximal stenosis in the RCA. According to the range of these variables obtained from clinical data, the ratio of the GEA flow to the flow of the RCA distal to the anastomosis was calculated. RESULTS: Main factors to determine the flows in the two parallel paths were the inner diameters of both vessels, and the degree of the proximal stenosis. When the inner diameters of the GEA were 0.5 mm larger than that of the RCA, the GEA carried more than 50% of the total flow of the RCA distal to the anastomosis despite a moderate stenosis in the RCA. When the inner diameter of the GEA was equal to, or 0.5 mm smaller than, that of the RCA, the GEA flow was dominated by the native RCA flow unless the proximal stenosis was critical. CONCLUSIONS: If the inner diameter of the GEA is 0.5 mm larger than that of the RCA, CABG with the GEA can be applied more widely. If not, the application would basically be limited.

Coronary Artery Bypass↗

PubMed2000

Oral glucose retention, saliva viscosity and flow rate in 5-year-old children.

There are significant differences of glucose retention in site-specificity and individuals. Sixty-two 5-year-old nursery schoolchildren participated in this study on the relation between the viscosity of saliva and flow rate and glucose retention. Each child was instructed to rinse his/her mouth with a glucose solution (0.5 M, 5 ml) and then to spit out. Three minutes after rinsing, glucose retention was determined. Resting saliva was collected by a natural outflow method, then the flow rate was determined. A rotational viscometer was used to determine the viscosity. Glucose retention and flow rate were correlated at the left maxillary primary molars, and glucose retention and viscosity were correlated at the maxillary central primary incisors. It was concluded that glucose retention after glucose mouth rinsing was site-specific, and that glucose retention and the index of decayed, missing and filled primary teeth (dmft) were slightly correlated with the salivary viscosity and flow rate.

Analysis of Variance↗

PubMed1999

Chicken histone deacetylase-2 controls the amount of the IgM H-chain at the steps of both transcription of its gene and alternative processing of its pre-mRNA in the DT40 cell line.

Histone deacetylases (HDACs) are involved in the deacetylation of core histones, which is an important event in transcription regulation in eukaryotes through alterations in the chromatin structure. We cloned cDNAs and genomic DNAs encoding two chicken HDACs (chHDAC-1 and -2), which are preferentially localized in nuclei. Treatment with trichostatin A reduced the HDAC activities in immunoprecipitates obtained with anti-chHDAC-1 and -2 antisera. Using gene targeting techniques, we generated homozygous DT40 mutants, DeltachHDAC-1 and -2, devoid of two alleles of the chHDAC-1 and -2 genes, respectively. The protein patterns on two-dimensional PAGE definitely changed for DeltachHDAC-2, and the amounts of the IgM H- and L-chains increased in it. Of the two IgM H-chain forms, the secreted form mu(s) increased in DeltachHDAC-2, but the membrane-bound form mu(m) decreased. The IgM H-chain gene was transcribed more in DeltachHDAC-2 than in DT40 cells. In the mutant, the alternative processing of IgM H-chain pre-mRNA preferentially occurred, resulting in an increase in the amount of mu(s) mRNA, whereas the stability of the two types of mRNA, mu(s) and mu(m), was unchanged. In DT40 cells, treatment with trichostatin A increased both the amounts of IgM H-chain mRNAs and the switch from mu(m) to mu(s) mRNAs. Based on these results, we propose a model for a role of chHDAC-2 in both the transcription and alternative processing steps, resulting in control of the amount of the mu(s) IgM H-chain in the DT40 cell line.

Amino Acid Sequence↗