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Biomedical subjects

M Kitamura

Publications and source records attributed to M Kitamura.

At least 37 records · Page 2Linked to original sources
PubMed2001

Collagen remodeling and cardiac dysfunction in patients with hypertrophic cardiomyopathy: the significance of type III and VI collagens.

BACKGROUND: The relationship between the extent of myocardial interstitial fibrosis, the percentage of each type of collagen, and cardiac function in patients with hypertrophic cardiomyopathy (HC) has not been established. HYPOTHESIS: The study aimed to establish that increases in some types of collagen may correlate with cardiac dysfunction. METHODS: Mallory-Azan staining and immunohistochemical staining by the avidin-biotin-complex (ABC) method using anticollagen antibodies were performed on the myocardial biopsy specimens in 35 patients with HC, and the percentage and type of collagen present was determined. Left ventricular (LV) function was evaluated by cardiac catheterization and ventriculography. RESULTS: The percentage of myocardial interstitial fibrosis correlated highly with indices of LV diastolic and systolic function. The amount of type III collagen correlated significantly with the peak negative dp/dt, the rapid filling volume/stroke volume, and the ejection fraction (EF). Significant correlations also were noted between the amount of type VI collagen and peak negative dp/dt, peak positive dp/dt, and EF. Type I collagen did not correlate with any of the LV function indices, and type IV collagen correlated only with peak ejection rate. Type V collagen did not accumulate substantially in the myocardial interstitium. CONCLUSIONS: The progression of myocardial interstitial fibrosis in the HC heart adversely impacts both the diastolic and systolic function of the LV. Increases in the percentage of type III and VI collagen correlate with cardiac dysfunction.

Adolescent↗
PubMed2001

Self and nonself recognition of chiral catalysts: the origin of nonlinear effects in the amino-alcohol catalyzed asymmetric addition of diorganozincs to aldehydes.

Asymmetric addition of dialkylzincs to aldehydes in the presence of (2S)-3-exo-(dimethylamino)isoborneol [(S)-DAIB] exhibits various nonclassical phenomena. The enantiomeric excess (ee) of the alkylation product, obtained with partially resolved DAIB, is much higher than that of the chiral amino alcohol, while the rate decreases considerably as the ee of DAIB is lowered. The asymmetric amplification effects reflect the relative turnover numbers of two enantiomorphic catalytic cycles, where an essential feature is the reversible homochiral and heterochiral dimerization of the coexisting enantiomeric DAIB-based Zn catalysts. The interplay between the thermodynamics of the monomer/dimer equilibration and the kinetics of alkylation reaction strongly affect the overall profile of asymmetric catalysis. The self and nonself recognition of the chiral Zn catalysts is a general phenomenon when (S)-DAIB is mixed with its enantiomer, diastereomer, or even an achiral beta-amino alcohol. The degree of nonlinearity is highly affected not only by the structures and purity of catalysts but also by various reaction parameters. The salient features have been clarified on the basis of molecular weight measurements, NMR and X-ray crystallographic studies of organozinc complexes, and kinetic experiments, as well as computer-aided quantitative analysis.

Journal Article↗
PubMed2001

Cancer of the gastric tube reconstructed through the posterior mediastinal route after radical surgery for esophageal cancer.

Among 750 patients diagnosed with esophageal carcinoma in our department between 1972 and 1997, we reviewed our 10 cases in which cancer occurred within gastric tubes reconstructed through the posterior mediastinal route after radical surgery for esophageal cancer. The interval between esophagectomy and cancer onset in the reconstructed gastric tube was relatively long (mean interval: 72 months). Five of our 10 subjects had gastric tube cancer detected at follow-up endoscopy. Four underwent total or partial gastric tube resection with open thoracotomy using colonic or jejunal reconstruction; 3 underwent endoscopic resection. To the best of our knowledge, this is the first report on patients undergoing total resection of gastric tubes reconstructed through the posterior mediastinal route after esophagectomy and rereconstruction using the pedicled colon for the gastric tube cancer.

Aged↗
PubMed2001

GABA(A) agents injected into the ventral pallidum differentially affect dopaminergic pivoting and cholinergic circling elicited from the shell of the nucleus accumbens.

The ability of GABA(A) receptors in the ventral pallidum to modulate shell-specific behavior was studied. Injections of the non-selective acetylcholine receptor agonist, carbachol (5 microg), into the shell of the nucleus accumbens elicited contraversive circling, namely turning marked by normal stepping; in contrast, injections of a mixture of dopamine D(1) (SKF 38393, 5 microg) and D(2) (quinpirole, 10 microg) receptor agonists into this brain structure elicited contraversive pivoting, namely turning marked by abnormal hindlimb stepping. Unilateral injections of the GABA(A) receptor agonist muscimol (10, 25 and 50 ng) into the ventral pallidum dose-dependently mimicked shell-specific circling, especially when given at a level +8.6mm anterior to the interaural line; this effect was GABA(A) receptor specific, because it was prevented by the GABA(A) receptor antagonist bicuculline (150 ng). Unilateral pallidal injections of a dose of muscimol that was ineffective per se (10 ng) abolished contraversive pivoting elicited by shell injections of dopamine receptor agonists; instead, it elicited moderate ipsiversive pivoting. Pallidal injections of bicuculline (150 ng) replaced the contraversive pivoting elicited by dopamine receptor agonist with ipsiversive circling. In contrast, unilateral pallidal injections of 10 ng muscimol (anterior +8.6mm level) suppressed the contraversive circling elicited by shell injections of carbachol; instead, it elicited moderate ipsiversive pivoting. Pallidal injections of bicuculline (150 ng) produced short-lasting ipsiversive circling that was followed by contraversive pivoting. We conclude that the ventromedial portion of the ventral pallidum contains GABA(A) receptors that are crucial for the transmission of information from the shell of the nucleus accumbens via the ventral pallidum towards other brain structures; this holds especially for information about shell-specific circling elicited by carbachol. The same portion of the ventral pallidum also contains GABA(A) receptors that control the transfer of information from the nucleus accumbens towards structures outside the ventral pallidum; this holds especially for information about shell-specific pivoting elicited by dopaminergic agonists.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed2001

Rapid and simple determination of mycophenolic acid in human plasma by ion-pair RP-LC with fluorescence detection.

Mycophenolic acid (MPA) is an immunosuppressive drug given as the prodrug of mycophenolate mofetil (MMF). In order to investigate the pharmacokinetics of MPA, a simple, specific, sensitive and reliable method has been established for the quantitative determination of MPA in plasma from renal transplant recipients. The method involves a single-step protein precipitation procedure and a specific determination by ion-pair reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection. Separation was achieved on a C18 column (150 x 4.6 mm, 5 microm) with a mobile phase composed of borate buffer (pH 10.0; 50 mM)--acetonitrile--tetrabutylammonium bromide (200 mM) (75:25:1, v/v/v). The fluorescence detector was set at 310 (excitation) and 430 nm (emission). Following protein precipitation with ice-cold acetonitrile, clear supernatants (50 microl) were injected into the HPLC system. The retention time of MPA was approximately 4.5 min. The HPLC run time was 8 min. The assay was linear in concentration range 0.2-20.0 microg/ml for MPA in human plasma. Precision of the assay in the concentration range examined was from 0.89 to 3.21% for the intra-assay run and from 3.01 to 4.35% for the inter-assay run. A limit of detection was 0.05 microg/ml at a signal-to-noise ratio of 3. This validated method was then applied to the determination of MPA concentrations in renal transplant recipients after oral administration of 0.75 g of MMF.

Chromatography, High Pressure Liquid↗
PubMed2001

Porphyromonas gingivalis-specific IgG subclass antibody levels as immunological risk indicators of periodontal bone loss.

BACKGROUND: It has been well demonstrated a positive association between the magnitude of host antibody response and periodontal disease status. Previous studies also reported that Porphyromonas gingivalis-specific IgG subclass antibodies were elevated in sera from adult periodontitis patients. However, the rôle and the association of these IgG subclass antibodies to the development of periodontal diseases are poorly understood. AIM: The aim of present investigation was to examine the relation of serum IgG subclass antibody levels and alveolar bone loss in treated and untreated periodontitis patients. METHODS: Serum samples were taken from 20 treated and maintained periodontitis patients (SPT patients), 30 untreated patients and 19 periodontally healthy subjects. We determined the IgG subclass antibody titers to P. gingivalis whole cells using an enzyme-linked immunosorbent assay (ELISA). Subgingival plaque samples were taken from the mesio-buccal surface of 6 randomly selected teeth of SPT patients and evaluated for the presence of P. gingivalis by immunofluorescence microscopy. Clinical measurements were also taken including full mouth intraoral radiographs to measure interproximal alveolar bone loss at baseline (BLS1) and at a 5-year recall visit in the SPT patients (BLS2). RESULTS: Our results indicated that both patient groups had detectable levels of IgG1, IgG2, and IgG4. Significantly higher IgG1 was observed in both patient groups compared to the healthy subjects. The untreated patients also exhibited significantly elevated IgG2 response (p<0.05). The mean IgG4 level of the SPT patients was significantly higher compared to the other subject group (p<0.05). A statistically significant positive correlation between IgG2 levels and changes in bone levels (DeltaBLS: BLS2-BLS1) was seen in the SPT patients (p<0.001). SPT patients with high IgG2 and low IgG4 showed greater bone loss than those with low IgG2 and high IgG4 (p<0.05), although the mean prevalence of P. gingivalis in the 2 groups did not differ significantly. CONCLUSION: Our data suggest that the prolonged IgG2 response after periodontal treatment may be indicative of recurrent or persistent periodontal destruction.

Adult↗
PubMed2001

Chromosomal variants among 1790 infertile men.

BACKGROUND: The largest cytogenetic survey involving infertile men was undertaken to clarify whether chromosomal abnormalities, including autosomal abnormalities, affect semen qualities. METHOD: All male patients who visited an infertility clinic from 1990 to 1998 underwent chromosomal and semen analysis. RESULTS: Chromosomal abnormalities were found in 225 of 1790 patients (12.6%). The most frequent anomaly was Klinefelter syndrome (64 cases). Autosomal anomalies accounted for 126 cases. 46,XY,1qh(+) was the most common autosomal anomaly (30 cases) and its incidence was significantly higher than those of normal controls. The seminograms of these patients varied widely, with nine patients having azoospermia and three patients achieving natural pregnancies. It is not yet clear if this karyotype affects spermatogenesis. CONCLUSION: Autosomal anomalies as well as sex chromosomal abnormalities might affect spermatogenesis. Cytogenetic study is important before intracytoplasmic sperm injection.

Chromosome Aberrations↗
PubMed2001

Expression, regulation, and function of inhibitor of apoptosis family genes in rat mesangial cells.

BACKGROUND: The inhibitor of apoptosis (IAP) family of proteins regulates programmed cell death triggered by various stimuli. The purpose of this investigation was to examine the expression, regulation, and function of IAP genes in cultured rat mesangial cells. METHODS: Basal and inducible expression of c-IAP1, c-IAP2, XIAP, and TIAP mRNAs was examined in mesangial cells, isolated glomeruli, and other cell lines under unstimulated and tumor necrosis factor-alpha (TNF-alpha)-stimulated conditions. To examine a role of nuclear factor-kappa B (NF-kappa B) in the regulation of IAPs, expression of IAPs in NF-kappa B-inactive mesangial cells was compared with that in wild-type cells. To investigate roles of IAPs in mesangial cell apoptosis, NF-kappa B--inactive cells were stably supertransfected with c-IAP1 or c-IAP2, and the susceptibility of these cells to TNF-alpha--induced apoptosis was evaluated quantitatively. RESULTS: Substantial, constitutive expression of c-IAP2, XIAP, and TIAP was observed in serum-deprived rat mesangial cells and c-IAP2 and XIAP in isolated normal rat glomeruli. In response to TNF-alpha, expression of c-IAP1 and c-IAP2 was induced in HeLa cells and ECV304 endothelial cells, but not in mesangial cells. In contrast to previous reports on other cell types, the expression of IAPs in rat mesangial cells was independent of NF-kappa B; that is, expression levels of IAPs in NF-kappa B--inactive cells were same as those in NF-kappa B--active cells under both unstimulated and TNF-alpha--stimulated conditions. Even without the induction of IAPs, NF-kappa B--active mesangial cells were more resistant to TNF-alpha--induced apoptosis than NF-kappa B--inactive cells. Interestingly, overexpression of either c-IAP1 or c-IAP2 completely compensated for the lack of resistance to apoptosis in NF-kappa B--inactive cells. CONCLUSIONS: IAPs are constitutively expressed in cultured rat mesangial cells and isolated normal rat glomeruli. IAPs can contribute to the survival of rat mesangial cells, but unexpectedly, these molecules are not involved in the TNF-alpha--induced, NF-kappa B--dependent cytoprotection in this cell type.

Animals↗
PubMed2001

Cloning and expression of the catalase gene from the anaerobic bacterium Desulfovibrio vulgaris (Miyazaki F).

We identified a gene encoding a catalase from the anaerobic bacteria Desulfovibrio vulgaris (Miyazaki F), and the expression of its gene in Escherichia coli. The 3.3-kbp DNA fragment isolated from D. vulgaris (Miyazaki F) by double digestion with EcoRI and SalI was found to produce a protein that binds protoheme IX as a prosthetic group in E. coli. This DNA fragment contained a putative open reading frame (Kat) and one part of another open reading frame (ORF-1). The amino acid sequence of the amino terminus of the protein purified from the transformed cells was consistent with that deduced from the nucleotide sequence of Kat in the cloned fragment of D. vulgaris (Miyazaki F) DNA, which may include promoter and regulatory sequences. The nucleotide sequence of Kat indicates that the protein is composed of 479 amino acids per monomer. The recombinant catalase was found to be active in the decomposition of hydrogen peroxide, as are other catalases from aerobic organisms, but its K(m) value was much greater. The hydrogen peroxide stress against D. vulgaris (Miyazaki F) induced the activity for the decomposition of hydrogen peroxide somewhat, so the catalase gene may not work effectively in vivo.

Amino Acid Sequence↗
PubMed2001

Loss of mRor1 enhances the heart and skeletal abnormalities in mRor2-deficient mice: redundant and pleiotropic functions of mRor1 and mRor2 receptor tyrosine kinases.

The mammalian Ror family of receptor tyrosine kinases consists of two structurally related proteins, Ror1 and Ror2. We have shown that mRor2-deficient mice exhibit widespread skeletal abnormalities, ventricular septal defects in the heart, and respiratory dysfunction, leading to neonatal lethality (S. Takeuchi, K. Takeda, I. Oishi, M. Nomi, M. Ikeya, K. Itoh, S. Tamura, T. Ueda, T. Hatta, H. Otani, T. Terashima, S. Takada, H. Yamamura, S. Akira, and Y. Minami, Genes Cells 5:71-78, 2000). Here we show that mRor1-deficient mice have no apparent skeletal or cardiac abnormalities, yet they also die soon after birth due to respiratory dysfunction. Interestingly, mRor1/mRor2 double mutant mice show markedly enhanced skeletal abnormalities compared with mRor2 mutant mice. Furthermore, double mutant mice also exhibit defects not observed in mRor2 mutant mice, including a sternal defect, dysplasia of the symphysis of the pubic bone, and complete transposition of the great arteries. These results indicate that mRor1 and mRor2 interact genetically in skeletal and cardiac development.

Animals↗
PubMed2001

Genomic analysis of idiopathic infertile patients with sperm-specific depletion of CD46.

Three infertile subjects with no expression of CD46 (membrane cofactor protein of complement) on their spermatozoa were found when screening 542 idiopathic male infertile patients. The sperm CD46 isoform was reported to be associated with the sperm-egg interaction, yet a ubiquitous expression of CD46 confers resistance to complement-mediated injury on host cells. All three patients expressed normal CD46 isoforms on their lymphocytes and granulocytes. Thus, the loss of CD46 is sperm-specific, probably due to testicular germ cell-specific regulation of CD46 production. Recently, a mechanism of the gene regulation of human CD46 was elucidated in which the silencer element of the 3' UT and the promoter region of human CD46 gene partly participate. Here, we analyzed these regions of the CD46 gene in our 3 patients. We found no abnormality in 3' and 5' regions of the CD46 genome in the 3 patients. Thus, in these infertile patients sperm-specific depletion of CD46 is not governed by the so for identified regulators in the CD46 gene. Other unknown factors outside the known regulatory regions would play a role in the regulation of sperm-specific CD46 expression.

3' Untranslated Regions↗
PubMed2001

Explanted glomeruli: utility and limitations.

Ex vivo incubation of isolated glomeruli has been used for many years to investigate biochemical properties of glomeruli. However, little has been understood about whether and how isolation and explanation per se affect the structure and function of the glomerulus. We recently reported that ex vivo incubation of isolated normal glomeruli results in severe apoptosis of podocytes, activation of the family of mitogen-activated protein kinase and expression of several genes regulated by activator protein 1. In this article, we summarize our current findings and discuss the utility and limitations of explanted glomeruli.

Animals↗
PubMed2001

Periodontal regeneration by FGF-2 (bFGF) in primate models.

We recently demonstrated that a topical application of basic fibroblast growth factor (FGF-2; bFGF) to alveolar bone defects in beagle dogs enhanced periodontal regeneration. The purpose of this study was further characterization of the biological effects of FGF-2 in non-human primates. Thirty-two inflamed furcation class II defects were surgically created in 4 male primates. The gelatinous carrier alone or the carrier containing 0.1 or 0.4% human recombinant FGF-2 was topically applied to the defects and compared with no treatment. Eight weeks after application, the periodontal regeneration in those defects was analyzed. In all FGF-2-treated sites, significant periodontal regeneration was dose-dependently observed in greater amounts than in the carrier-treated or non-treated sites. No instances of epithelial down-growth, ankylosis, or root resorption were observed in the FGF-2-treated sites. These results indicate that a topical application of FGF-2 can enhance considerable periodontal regeneration in surgically created furcation class II defects of non-human primates.

Alveolar Bone Loss↗
PubMed2001

A sensitive method for detecting Porphyromonas gingivalis by polymerase chain reaction and its possible clinical application.

BACKGROUND: It is useful for the clinical diagnosis of periodontitis to monitor the colonization of periodontopathic bacteria in periodontal pockets. In this study, we attempted to establish and possibly identify the clinical application of a sensitive method to detect Porphyromonas gingivalis (P.g.), one of the putative periodontopathic bacteria related to chronic periodontitis. METHODS: Genomic DNA extracted from cultured P.g. 381 and clinically isolated subgingival plaque samples were used as a template of polymerase chain reaction (PCR). We designed primers to amplify the genomic DNA coding 40 kDa outer membrane protein (OMP), one of the unique proteins to all strains of P.g. The efficiency and specificity of amplification were evaluated by agarose gel electrophoresis and subsequent Southern hybridization with a digoxygenin-labeled oligonucleotide probe. RESULTS: Fewer than 100 P.g. bacterial cells in the specimen were reproducibly detected by PCR-hybridization assay. This PCR-hybridization assay was at least 100 times more sensitive than the conventional indirect immunofluorescence assay (IIF). Furthermore, the imaging analysis showed that there is a linear correlation between the strength of the signal and the cell number of P.g. from which the template DNA was extracted semiquantitatively. It is noteworthy that the PCR assay could also be applied to detect P.g. from clinical plaque samples and that it was approximately 100 times more sensitive than a conventional IIF assay. CONCLUSION: The PCR assay established in this study can be a powerful tool to detect P.g. in periodontal pockets and monitor the colonization and/or recolonization of P.g. at the very early phase.

Bacterial Outer Membrane Proteins↗
PubMed2001

[Cholesterol embolism after percutaneous transluminal coronary angioplasty procedure: a case report].

A 68-year-old man with chest pain was treated under a diagnosis of angina pectoris based on coronary angiography by percutaneous transluminal coronary angioplasty including stent implantation performed by the femoral approach. About 1 month after intervention, his renal function deteriorated and purpura appeared on both feet, especially at the toe tips. He was treated under a tentative diagnosis of cholesterol embolism conservatively at the out-patient clinic. However, he was admitted by ambulance due to worsening renal failure 2 months later and died from multiple organ failure 2 weeks after admission. Autopsy examination identified cholesterol embolism due to crystal emboli in several organs. Cholesterol embolism rarely occurs after angiographic or interventional procedures, but is difficult to diagnose clinically and there is no established therapy. The number of intervention and angiography procedures is increasing, so the occurrence of embolism as a complication of these procedures might also increase.

Aged↗