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Biomedical subjects

S Kawano

Publications and source records attributed to S Kawano.

At least 19 recordsLinked to original sources
PubMed2006

Combination study of myocardial perfusion and left ventricular filling provides an excellent prediction of clinical outcomes in patients with reperfused myocardial infarction.

The no reflow phenomenon and left ventricular (LV) diastolic dysfunction are surrogate markers of poor outcomes in patients with myocardial infarction (MI). We studied the relationship between contrast perfusion defects and restrictive filling patterns for predicting prognosis after MI. Mitral inflow velocity and myocardial contrast perfusion were studied 2 weeks after reperfusion in 226 consecutive patients with acute MI. The cohort was divided into two groups according to the number of perfusion defect segments (PD); large-PD and small-PD. Mitral inflow was classified into two categories according to deceleration time; non-restrictive and restrictive. The patients were divided into 4 groups (small-PD/non-restrictive, n = 124; small-PD/restrictive, n = 29; large-PD/non-restrictive, n = 50; large-PD/restrictive, n = 23). LV end-diastolic volume index was the greatest and cardiac event rate was the highest in large-PD/restrictive, followed by large- PD/non-restrictive, small-PD/restrictive, and by small- PD/non-restrictive (81 +/- 19 vs. 74 +/- 17 vs. 66 +/- 19 vs. 59 +/- 15 ml/m2, events: 61 % vs. 16% vs. 14% vs. 8 %). Multivariate analysis revealed the large-PD is the most powerful predictive factor related to cardiac events (odds ratio = 5.5, P = 0.004) followed by the restrictive filing pattern (4.3, P = 0.005). Co-existence of large-PD and restrictive filling is a strong predictor of adverse outcomes in the patients with MI.

Aged↗
PubMed2006

Troglitazone inhibits cell growth and induces apoptosis of B-cell acute lymphoblastic leukemia cells with t(14;18).

Peroxisome proliferator-activated receptor-gamma (PPARgamma), a member of the nuclear receptor superfamily, has been detected in several human leukemia cells. Recent studies reported that PPARgamma ligands inhibit cell proliferation and induce apoptosis in both normal and malignant B-lineage cells. We investigated the expression of PPARgamma and the effects of PPARgamma ligands on UTree-O2, Bay91 and 380, three B-cell acute lymphoblastic leukemia (B-ALL) cell lines with t(14;18), which show a poor prognosis, accompanying c-myc abnormality. Western blot analysis identified expression of PPARgamma protein and real-time PCR that of PPARgamma mRNA on the three cell lines. Troglitazone (TGZ), a synthetic PPARgamma ligand, inhibited cell growth in these cell lines in a dose-dependent manner, which was associated with G(1) cell cycle arrest and apoptosis. We also found this effect PPARgamma independent since PPARgamma antagonists failed to reverse this effect. We assessed the expression of c-myc, an apoptosis-regulatory gene, since c-myc abnormality was detected in most B-ALL cells with t(14;18). TGZ was found to dose-dependently downregulate the expression of c-myc mRNA and c-myc protein in the three cell lines. These results suggest that TGZ inhibits cell growth via induction of G(1) cell cycle arrest and apoptosis in these cell lines and that TGZ-induced apoptosis, at least in part, may be related to the downregulation of c-myc expression. Moreover, the downregulation of c-myc expression by TGZ may depend on a PPARgamma-independent mechanism. Further studies indicate that PPARgamma ligands may serve as a therapeutic agent in B-ALL with t(14;18).

Adolescent↗
PubMed2006

[Extensive educational program for high performance medical technologists].

The education system for medical technologists has recently been revolutionized, their educational periods vary from 2 to 9 years, and some already have doctoral degrees. In such a new situation, our faculty thinks that the most important point for new medical technologists is the ability to have a broad view of the clinical fields, especially the view of patients. Special training in bed-side education and a stint in several divisions, such as the surgical operation room, rehabilitation. radiological examination room, pharmacy, central storage room of medical records, and medical informatics, and so on, of the hospital is a powerful tool to obtain a broad view of the various clinical fields and can be essential for developing high performance medical technologists. As nine years have passed since starting this education, we evaluated this practice through systematic personal communication. As a result, it was found to be extremely effective for many reasons such as having a continuous image of the patient when they examine the blood sample in the hospital laboratory, showing advanced laboratory performance, and having no mental barrier to visiting the wards and so on. The abilities of our alumni are praised highly by many large scale hospitals around the country and 50% of them are working in the clinical laboratory division of these hospitals. About 40% are working in the division of research and development in various companies. We express sincere thanks to the director and all cooperative individuals for this course in the Osaka University Hospital.

Curriculum↗
PubMed2005

Patency assessment of the internal jugular vein after neck dissection.

Twenty-seven patients with oral malignant tumours, who underwent neck dissection with preservation of the internal jugular vein (IJV), were studied retrospectively to evaluate patency of the IJV. Twenty-three patients underwent ablative surgery of the primary lesion with neck dissection and 4 underwent neck dissection alone. Three patients received simple closure and skin grafting of the primary lesion, and 20 received reconstruction surgery (4 platysma flaps, 3 radial forearm flaps, 3 lateral upper arm flaps, 2 pectoralis major myocutaneous flaps and 8 rectus abdominis myocutaneous flaps). The maximum and minimum diameters of the IJV as measured on computed tomographic (CT) scans were used to assess patency. The cross-sectional area of the IJV and the ratio of its long axis to short axis (L/S ratio) were calculated. The relation between the change in IJV status and the type of flap used for reconstruction was also examined. Occlusion of the IJV was present in 3.7% of the patients, and 'narrowing' was present in 63.6%. The size of the flap significantly correlated with 'narrowing' of the IJV, suggesting that 'narrowing' was caused mainly by compression due to the flap.

Carcinoma, Squamous Cell↗
PubMed2004

Effect of mutated transporters associated with antigen-processing 2 on characteristic major histocompatibility complex binding peptides: analysis using electrospray ionization tandem mass spectrometry.

A novel allele of transporters associated with the antigen-processing (TAP) 2 gene, TAP2*Bky2 (Val(577)), is significantly increased in Japanese patients with Sjögren's syndrome (SS), and has a strong association with SS-A/Ro autoantibody production in SS and autoantibody including anti-SS-A/Ro and anti-U1 RNP antibody in systemic lupus erythematosus (SLE). To determine the influence of this natural mutated TAP on peptides loaded onto MHC class I, we analyzed the repertoire of peptides loaded onto MHC class I on transfectants with TAP1 and TAP2 or mutated TAP2 by electrospray ionization tandem mass spectrometry (ESI-MS/MS). After comparison of the peptide profiles we identified three peptides from only mutated TAP transfectants. Moreover, one of these peptides is derived from snRNP A, which is a target for anti-U1 RNP antibody. To our knowledge this is the first report to show that the natural mutation of TAP2 changes the peptide profile loaded onto MHC class I molecules.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

The effect of nalidixic acid on growth and reproductive events in nucleocytosolic and chloroplast compartments in the alga Scenedesmus quadricauda.

The courses of rRNA accumulation, DNA replication, and nuclear division were followed both in the chloroplast and the nucleocytosolic compartments during the cell cycle in synchronized populations of the chlorococcal alga Scenedesmus quadricauda. Control and nalidixic acid-treated cultures were compared. Nalidixic acid (150 mg/L) was added either at the beginning of the cell cycle or consecutively during the cell cycle to subcultures transferred into the dark. If the inhibitor was applied at the beginning of the cell cycle, chloroplast DNA did not replicate and nucleoids did not divide. Chloroplast division, however, was coordinated in a timely fashion with cytokinesis even under conditions of blocked chloroplast DNA replication. While the growth rate was slowed down, the courses of reproductive processes in the nucleocytosolic compartment were not affected and their timing and the number of rounds were coordinated with growth rate as in the control culture. The rate of cytosolic rRNA synthesis was lower but no apparent effect was seen on the amount of rRNA that accumulated during the cell cycle. In contrast, lower levels of chloroplast rRNA were found at the end of the cell cycle compared with the control culture. Experiments in which cells were transferred to the dark during the cell cycle showed that the inhibitor affected none of the reproductive events in the nucleocytosolic compartment. In the chloroplast compartment, DNA replication was inhibited in inhibitor-treated cultures, but was unaffected in controls. The chloroplast nucleoids themselves divided even in the presence of the inhibitor, reducing their DNA content to a level which corresponded to that in freshly formed control daughter cells.

Chloroplasts↗
PubMed2004

Helicobacter bilis infection in biliary tract cancer.

BACKGROUND: Biliary tract cancer is a highly fatal disease with poor prognosis, but the aetiology is poorly understood. AIM: We aimed to identify Helicobacter bilis infection in the gallbladder in patients with biliary tract disease. METHODS: Archival gallbladder specimens from 34 patients (14 males and 20 females) with an average age of 61.4 +/- 12.2 years (mean +/- SE) were retrieved, consisting of 11 cases of gallbladder cancer, three of bile duct cancer, 16 of cholecystolithiasis and four of pancreatic cancer. DNA was extracted and nested PCR using primers specific for 16S rRNA of H. bilis was performed. RESULTS: Amplification was observed in 3 of 11 gallbladder cancer cases (27.2%) and one of three cases with biliary duct cancer (33.3%). In total, four of 14 cases with biliary tract cancer were positive for H. bilis (28.6%). In addition, the presence of H. bilis was shown in two of 16 cases (12.5%) with cholecystolithiasis. Notably, although the number of cases examined was small, none of the four cases with pancreatic cancer showed the presence of H. bilis infection in the gallbladder without apparent abnormalities. CONCLUSION: H. bilis infection may play a role in biliary tract disease, particularly in biliary tract cancer.

Biliary Tract Neoplasms↗
PubMed2004

Characterization of dental epithelial progenitor cells derived from cervical-loop epithelium in a rat lower incisor.

Dental epithelial progenitor cells differentiate into various cell types during development of tooth germs. To study this mechanism, we produced immortalized dental epithelial progenitor cells derived from the cervical-loop epithelium of a rat lower incisor. The expression patterns of cytokeratin 14, nerve growth factor receptor p75, amelogenin, Notch2, and alkaline phosphatase were examined by immunohistochemistry in both lower and higher cell densities. The patterns of each were compared in the dental epithelium of rat lower incisors. The results demonstrated that these cells could produce ameloblast lineage cells, stratum intermedium cells, stellate reticulum, and outer enamel epithelium. Furthermore, fibroblast growth factor 10 stimulated proliferation of dental progenitor cells and subsequently increased the number of cells expressing alkaline phosphatase. These results suggest that fibroblast growth factor 10 plays a role in coupling mitogenesis of the cervical-loop cells and the production of stratum intermedium cells in rat incisors.

Alkaline Phosphatase↗
PubMed2004

Infrared absorption enhancement of C60 by overlaying thin silver island films.

Normal-incidence infrared absorption has been observed for silver overlaid C(60) thin films formed on surface-oxidized Si(111) substrates as a function of the silver or C(60) film thickness. The absorption spectra exhibit bands at 1429 and 1180 cm(-1) due, respectively, to the infrared active T(lu) (4) and T(lu) (3) modes of C(60) in multi-layers. Additionally, two bands appear at 1442 and 1370 cm(-1). The former band is caused by activation of the infrared inactive (Raman active) A(g) (2) mode via electron transfer from the silver to adsorbed C(60), and the latter is assigned to the T(1u) (4) mode red-shifted by the charge transfer. These bands are all enhanced in intensity dependent either upon the silver or C(60) thickness, i.e., the largest absorption enhancement is obtained for 25-monolayers-thick silver and 12-nm-thick C(60). Under atomic force microprobe inspection, the average size and height of the islands in the overlaid 25-monolayers-thick silver change with underlying C(60) film thickness. The influence of the C(60) film structure upon the silver film and in turn the absorption intensity is strongly suggested.

Journal Article↗
PubMed2003

Review article: inflammation-related promotion of gastrointestinal carcinogenesis--a perigenetic pathway.

Chronic inflammation has been reported to accelerate neoplasmas in gastrointestinal tract. Certain bacteria including Helicobacter pylori directly interact with host cells, induce proinflammatory cytokines and stimulate production of free radicals. Free radicals cause mutations in target cells so that neoplastic clones are established. Accumulation of such genetic alterations may cause malignant transformation of some established clones. In addition, inflammatory alterations may promote growth, expansion and invasion of gastrointestinal epithelial cells. The latter changes caused by inflammation may occur even without further genetic mutations or epigenetic alterations, and therefore may be categorized as 'perigenetic alterations' of neoplastic cells. For an example, tumour necrosis factor alpha (TNF-alpha) plays pivotal roles not only in the reduction but also in the growth, invasion and metastases of certain neoplasmas. Our studies show that TNF-alpha increases intracellular radical production, degradates E-cadherin / beta-catenin complex and promotes dispersion and migration in epithelial cells transformed with an activated src oncogene (v-src). These data indicate that an inflammatory cytokine induces the malignant potential of src-activated neoplastic cells. Interestingly, TNF-alpha also induced these phenotypic changes in nonmutated cells whose c-Src was activated by TGF-alpha, suggesting that the invasive properties of the cell were not necessarily related to gene mutation. Furthermore, certain radical scavengers suppressed the invasive phenotype of the cells. These results indicate that perigenetic alterations are an important target of pharmacological intervention of carcinogenesis.

Cell Communication↗
PubMed2003

Miniature vibrating flow blood pump using a cross-slider mechanism for external shunt catheter.

The prototype of the miniature vibrating flow pump (VFP) is developed for the external shunt catheter. The cross-slider mechanism is applied to vibrate the tube, which causes the pumping effect. This mechanism results in successful development of the miniature and lightweight VFP. By the use of the prototype VFP, the experiment of the basic pump performance is made in detail based on the authorized procedure in the research field of fluids engineering. The typical H-Q curve of VFP, which is the relationship between the pump head and the flow rate, can be obtained. This result suggests that the miniature VFP developed here can be expected to be used as the booster pump for the external shunt catheter in clinical applications.

Arteriovenous Shunt, Surgical↗
PubMed2003

Rapid, selective digestion of mitochondrial DNA in accordance with the matA hierarchy of multiallelic mating types in the mitochondrial inheritance of Physarum polycephalum.

Although mitochondria are inherited uniparentally in nearly all eukaryotes, the mechanism for this is unclear. When zygotes of the isogamous protist Physarum polycephalum were stained with DAPI, the fluorescence of mtDNA in half of the mitochondria decreased simultaneously to give small spots and then disappeared completely approximately 1.5 hr after nuclear fusion, while the other mitochondrial nucleoids and all of the mitochondrial sheaths remained unchanged. PCR analysis of single zygote cells confirmed that the loss was limited to mtDNA from one parent. The vacant mitochondrial sheaths were gradually eliminated by 60 hr after mating. Using six mating types, the transmission patterns of mtDNA were examined in all possible crosses. In 39 of 60 crosses, strict uniparental inheritance was confirmed in accordance with a hierarchy of relative sexuality. In the other crosses, however, mtDNA from both parents was transmitted to plasmodia. The ratio of parental mtDNA was estimated to be from 1:1 to 1:10(-4). Nevertheless, the matA hierarchy was followed. In these crosses, the mtDNA was incompletely digested, and mtDNA replicated during subsequent plasmodial development. We conclude that the rapid, selective digestion of mtDNA promotes the uniparental inheritance of mitochondria; when this fails, biparental inheritance occurs.

Animals↗
PubMed2002

Characterization of Ca(2+) signaling pathways in human mesenchymal stem cells.

Human mesenchymal stem cells (HMSC) have the potential to differentiate into many cell types. The physiological properties of HMSCs including their Ca(2+) signaling pathways, however, are not well understood. We investigated Ca(2+) influx and release functions in HMSCs. In Ca(2+) imaging experiments, spontaneous Ca(2+) oscillations were observed in 36 of 50 HMSCs. The Ca(2+) oscillations were completely blocked by the application of 10 micro M cyclopiazonic acid (CPA) or 1 micro M thapsigargin (TG). A brief application of 1 micro M acetylcholine (ACh) induced a transient increase of [Ca(2+)](i) but the application of caffeine (10 mM) did not induce any Ca(2+) transient. When the stores were depleted with Ca(2+)-ATPase blockers (CPA or TG) or muscarinic agonists (ACh), store-operated Ca(2+) (SOC) entry was observed. Using the patch-clamp technique, store-operated Ca(2+) currents (I(SOC)) could be recorded in cells treated with ACh or CPA, but voltage-operated Ca(2+) currents (VOCCs) were not elicited in most of the cells (17/20), but in 15% of cells examined, small dihydropyridine (DHP)-sensitive Ca(2+) currents were recorded. Using RT-PCR, mRNAs were detected for inositol 1,4,5-trisphosphate receptor (InsP(3)R) type I, II, and III and DHP receptors alpha1A and alpha1H were detected, but mRNA was not detected for ryanodine receptor (RyR) or N-type Ca(2+) channels. These results suggest that in undifferentiated HMSCs, Ca(2+) release is mediated by InsP(3)Rs and Ca(2+) entry through plasma membrane is mainly mediated by the SOCs channels with a little contribution of VOCCs.

Calcium↗
PubMed2001

Pressure-derived collateral flow index as a parameter of microvascular dysfunction in acute myocardial infarction.

OBJECTIVES: The goal of this study was to examine the implications of the pressure-derived collateral flow index (CFIp) in acute myocardial infarction (AMI). BACKGROUND: Higher CFIp is associated with less severe myocardial ischemia during angioplasty in the non-infarcted heart. It remains unknown whether CFIp also identifies collateral function in AMI patients with and without no-reflow phenomenon. METHODS: The study population included 48 patients with a first AMI. After successful percutaneous transluminal coronary angioplasty (PTCA) stent, we measured mean aortic pressure (Pa), central venous pressure (Pv) and coronary wedge pressure (Pcw) of the infarct-related artery to calculate: CFIp = (Pcw - Pv)/(Pa - Pv). Myocardial contrast echocardiography (MCE) was performed with the intracoronary injection of microbubbles to assess myocardial perfusion. Left ventriculograms at days 1 and 28 were provided for the measurement of the regional wall motion (RWM, SD/chord). RESULTS: There was no difference in CFIp among subsets based on angiographic collateral grades (grade 0, 1, 2, 3; 0.28 +/- 0.07, 0.27 +/- 0.09, 0.27 +/- 0.08, 0.23 +/- 0.08, p = NS). The CFIp was significantly higher in patients with MCE no-reflow (n = 16) than in those with MCE reflow (n = 32) (0.34 +/- 0.07 vs. 0.23 +/- 0.06, p < 0.01). There was a significant inverse correlation between the extent of functional improvement (DeltaRWM[28 d-1 d]) and CFIp (r = 0.56, p < 0.01), implying that higher CFIp is associated with worse functional improvement. CONCLUSIONS: In AMI, CFIp is unlikely to reflect collateral function but seems to increase with the severity of microvascular dysfunction. Because higher CFIp was associated with poorer functional recovery, it provides a simple and useful estimate of clinical outcomes in AMI.

Aged↗
PubMed2001

Mutational analysis of the peroxisome proliferator-activated receptor gamma gene in human malignancies.

Peroxisome proliferator-activated receptor gamma (PPARgamma) plays an important role in adipocyte differentiation and is expressed in many human malignancies, including those from prostate, breast, as well as colon. It regulates differentiation and/or cell growth of these cells. However, expression of this nuclear hormone receptor in other types of cancer, especially in hematological malignancies, remains to be fully elucidated. The PPARgamma gene has been mapped to chromosome band 3p25, where chromosomal abnormalities are observed in a variety of human malignancies. Furthermore, a recent study revealed that the PPARgamma gene is functionally mutated in sporadic colon cancer cells. Therefore, PPARgamma could be an important tumor suppressor gene. This prompted us to investigate the expression and mutational status of the PPARgamma gene in cancers of a variety of tissues. A total of 159 samples were interrogated for their expression of PPARgamma as measured by reverse transcription-polymerase chain reaction and/or Western blot analysis. In each of the samples, expression of PPARgamma was detectable. In addition, a total of 397 clinical samples and cell lines including colon, prostate, breast and lung cancers, and leukemias were analyzed for mutations of the PPARgamma gene by either reverse transcription-polymerase chain reaction-single-strand conformation polymorphism or polymerase chain reaction-single-strand conformation polymorphism analysis. No abnormalities were detectable in any of the human malignancies. On the other hand, shifted bands were easily detectable when using positive controls, which harbored the same sequence alterations reported previously in colon cancer cells. Taken together, PPARgamma is expressed in a variety of cancers, and mutation of the PPARgamma gene is a very rare event in human malignancies.

Blotting, Western↗
PubMed2001

Gastric pneumatosis associated with duodenal stenosis and malrotation.

Pneumatosis intestinalis, which is linear or cystic gas within the bowel wall, is usually found in premature babies in association with necrotizing enterocolitis. Gastric pneumatosis defined as intramural gas of the stomach is a rare sign during infancy. We report an infant with Down's syndrome and a duodenal web with obvious gastric pneumatosis.

Down Syndrome↗
PubMed2001

The complete DNA sequence of the mitochondrial genome of Physarum polycephalum.

The complete sequence of the mitochondrial DNA (mtDNA) of the true slime mold Physarun polycephalum has been determined. The mtDNA is a circular 62,862-bp molecule with an A+T content of 74.1%. A search with the program BLAST X identified the protein-coding regions. The mitochondrial genome of P. polycephalum was predicted to contain genes coding for 12 known proteins [for three cytochrome c oxidase subunits, apocytochrome b, two F1Fo-ATPase subunits, five NADH dehydrogenase (nad) subunits, and one ribosomal protein], two rRNA genes, and five tRNA genes. However, the predicted ORFs are not all in the same frame, because mitochondrial RNA in P. polycephalum undergoes RNA editing to produce functional RNAs. The nucleotide sequence of an nad7 cDNA showed that 51 nucleotides were inserted at 46 sites in the mRNA. No guide RNA-like sequences were observed in the mtDNA of P. polycephalum. Comparison with reported Physarum mtDNA sequences suggested that sites of RNA editing vary among strains. In the Physarum mtDNA, 20 ORFs of over 300 nucleotides were found and ORFs 14 19 are transcribed.

Amino Acid Sequence↗