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Biomedical subjects

H Takemura

Publications and source records attributed to H Takemura.

At least 19 recordsLinked to original sources
PubMed2006

p21CDKN1A allows the repair of replication-mediated DNA double-strand breaks induced by topoisomerase I and is inactivated by the checkpoint kinase inhibitor 7-hydroxystaurosporine.

This study provides evidence for the importance of p21(CDKN1A) for the repair of replication-mediated DNA double-strand breaks (DSBs) induced by topoisomerase I. We report that defects of p21(CDKN1A) and p53 enhance camptothecin-induced histone H2AX phosphorylation (gammaH2AX), a marker for DNA DSBs. In human colon carcinoma HCT116 cells with wild-type (wt) p53, gammaH2AX reverses after camptothecin removal. By contrast, gammaH2AX increases after camptothecin removal in HCT116 cells deficient for p53 (p53-/-) or p21(CDKN1A) (p21-/-) as the cells reach the late-S and G2 phases. Since p21-/- cells exhibit similar S-phase arrest as wt cells in response to camptothecin and aphidicolin does not abrogate the enhanced gammaH2AX formation in p21-/- cells, we conclude that enhanced gammaH2AX formation in p21-/- cells is not due to re-replication. The cell cycle checkpoint abrogator and Chk1/Chk2 inhibitor 7-hydroxystaurosporine (UCN-01) also increases camptothecin-induced gammaH2AX formation and inhibits camptothecin-induced p21(CDKN1A) upregulation in HCT116 wt cells. TUNEL (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling) assays demonstrate that gammaH2AX formation in late S and G2 cells following CPT treatment corresponds to DNA breaks. However, these breaks are not related to apoptotic DNA fragmentation. We propose that p21(CDKN1A) prevents the collapse of replication forks damaged by stabilized topoisomerase I cleavage complexes.

Aphidicolin↗
PubMed2005

Comparison of NSP4 protein between group A and B human rotaviruses: detection of novel diarrhea-causing sequences in group B NSP4.

The human group B rotavirus is a causative agent of severe adult diarrhea. In this study, we analyzed the NSP4 structure of a group B rotavirus strain, CAL-1, and determined whether enterotoxin activity was present in CAL-1 NSP4. CAL-1 NSP4 was comprised of 219 amino acids which was longer than group A and C rotavirus NSP4, and the primary structures of their sequences differed considerably. However, CAL-1 NSP4 had an enterotoxin-like sequence (residues 106-127) that was only 27% identical to the enterotoxin region of NSP4 of KUN (a group A rotavirus strain) at residues 114-135. Interestingly, both of the synthetic peptides, one (residues 99-128) containing the enterotoxin-like sequence and the other (residues 191-219) containing 29 C-terminal amino acids of CAL-1 NSP4, induced diarrhea in 5.5-day-old mice, but not in 17.5-day-old mice, when administered parenterally. Thus, rotavirus "enterotoxin" sequences could be considerably divergent.

Age Factors↗
PubMed2005

Average P/F ratio during donor management for finding out the potential donor of lung procurement.

We investigated the potential donors from cases without lung procurement in spite of considering procurement as the donor. We reviewed 207 cases considered for lung procurement. Donors were divided into 2 groups according to whether or not their lungs were harvested: 50 did and 157 did not. We investigated their age, gender, donor management periods, blood pressure, heart rate, P/F ratio, PCO2, HCO3, positive end-expiratory pressure (PEEP), respiratory rate, abnormal findings in the chest X-ray, blood chemistries, sputum culture, and intravenous administration of steroid. Univariable or multivariable logistic regression analysis was used to predict lung harvesting by various factors. Univariable logistic regression analysis revealed maximum heart rate (HR) and respiratory rate (RR), maximum, minimum, and average P/F ratio, and abnormal findings in the chest X-ray, to be predictors to perform transplant. The maximum HR and RR of the non-harvest group are higher than those of the harvest group. Multivariable logistic regression analysis revealed average P/F ratio only to be a predictor to transplant. We divided the non-harvest group into 2 groups according to whether or not their P/F ratio was >300: 55 did (P/F 300 group) and 102 did not (P/F 299 group). Between P/F 299 group and the harvest group, univariable logistic regression analysis revealed maximum HR, maximum and minimum RR, maximum PEEP, maximum, minimum, and average P/F ratio, and abnormal findings in the chest X-ray to be predictors to transplant. Maximum HR, PEEP, and maximum and minimum RR of the P/F 299 group are higher than those of the harvest group. Maximum, minimum, and average P/F ratio of the P/F 299 group are lower than those of the harvest group. The average PCO2 of P/F 299 group is higher than that of the harvest group. The rate of abnormal findings in the chest X-ray of the P/F 299 group is higher than that of the harvest group. Multivariable logistic regression analysis revealed average P/F ratio only to be a predictor to transplant. There were no predictors between the P/F 300 group and the harvest group in both univariable and multivariable logistic regression analyses. Furthermore, there were no different factors between the P/F 300 group and the harvest group. Our study showed that 35.5% of the non-harvest group had a P/F ratio of >300 and had no difference compared with the harvest group. Our data suggest that potential donors existed in the non-harvest group and increased the number of lung procurement to 27.3% from 13.0% of all donors.

Blood Pressure↗
PubMed2005

Evaluation of a fully automated system (RAISUS) for rapid identification and antimicrobial susceptibility testing of Staphylococci.

RAISUS is a system for rapid bacterial identification and antimicrobial susceptibility testing. RAISUS and VITEK showed 97.8% and 75.9% agreement in identification of 45 Staphylococcus aureus strains and 58 coagulase-negative staphylococci (CoNS), respectively, and RAISUS and CLSI (formerly NCCLS) methods showed 87.2% and 87.9% agreement in the MICs for S. aureus and CoNS, respectively. RAISUS provided these data within 3.75 h, suggesting its utility for clinical bacteriological laboratories.

Anti-Bacterial Agents↗
PubMed2005

[Clinical experience with aortic connector system].

From April to December 2002, 40 patients underwent coronary artery bypass grafting (CABG) using the St. Jude Medical (Minneapolis) Symmetry bypass system (aortic connector system: ACS). 59 proximal anastomoses (51 saphenous vein grafts, 8 radial artery grafts) were performed with the ACS. One saphenous vein graft occluded during operation. Postoperative evaluation of the anastomotic patency was carried out by angiography in 45 grafts. Five of the saphenous vein grafts were occluded (5/38). One patient who was shock state before operation presented with postoperative unconsciousness. Another patient died at 8th postoperative day caused by ventricular fibrillation. We conclude that the ACS produces a simple, quick way of performing the proximal anastomosis without the need for clamping the aorta, allows reducing risk of embolization by aortic manipulation. However, it is necessary to discuss sufficiently using the ACS, because the graft patency with the ACS is lower than with standard suturing technique.

Aged↗
PubMed2005

[Arch first technique using handmade branched graft].

We created a method using handmade branched graft to do the aortic arch surgery easier and safer. We made the branched graft using 12 and 8 mm vascular graft. A 77-year-old man with Stanford type A aortic dissection was operated with this method under deep hypothermia. After aortic root manipulation, perfusion of the aortic arch was stopped and selective cerebral perfusion was established. Left subclavian artery (LSCA) was anastomosed to one of the branches. The perfusion of the LSCA was re-started via one of its branches. Respectively, left common carotid artery and brachiocephalic artery reconstruction and reperfusion were performed in a same fashion. After distal anastomosis, anastomosis between the branched graft and main graft was performed consecutively. Postoperative course was uneventful and there was no complication. The treatment of our branched graft was easier than that of ready-made 4-branched graft. We could perform the operation under clear view for its movability with minimal cerebral ischemic time.

Aged↗
PubMed2004

[Surgery for acute aortic dissection concomitant with preceding axillofemoral bypass to prevent malperfusion of visceral organs and limb ischemia].

A 52-year-old man was admitted with sudden onset of epigastralgia. Abdominal X-ray showed dilated intestine and computed tomography (CT) revealed extended type A aortic dissection. Marked abdominal distention and weak pulse of right femoral artery were recognized so malperfusion of visceral organs due to narrowing true lumen compressed by thrombosed false lumen was suggested. In the operation, right axillo-right femoral bypass was established preceding to median sternotomy. This graft was used as an arterial perfusion site of cardiopulmonary bypass, and replacement of the ascending aorta was performed under hypothermic circulatory arrest and retrograde cerebral perfusion. Sign of malperfusion of visceral organs was showed for several days after the operation but it disappeared without further intervention. Axillofemoral inflow of cardiopulmonary bypass may be effective procedure in these cases.

Anastomosis, Surgical↗
PubMed2003

Multiple minimally invasive direct CABG for the complete revascularization: the figure L approach.

BACKGROUND: Coronary artery bypass grafting on the beating heart via median sternotomy causes significant hemodynamic compromise during displacement of the heart, especially in patients with low ejection fraction or those who have potential catastrophic sternal reentry injuries. We have developed an innovative minimally invasive surgical approach (figure L Approach) for the treatment of multi-vessel coronary artery disease; especially in cases with huge hearts (> CTR 50 %) including tracheostomy requiring COLD, and redo cases. The objective of this study was to assess the efficacy and safety of this alternative surgical incision. METHODS: From January 1998 to March 2001, 22 patients underwent complete revascularization using this figure L Approach. Left submammary anterior thoracotomy incisions are made with the medial part of the incision vertically extending downward to the upper abdomen. The costal margin was divided. The pleural and peritoneal spaces were then entered. A chest retractor was placed to elevate the chest wall, exposing the heart and stomach. Two to four arterial grafts including LIT A, RGEA, RA and IEA were harvested. Revascularization of the LAD, LCX and distal RCA were performed in 22 patients without cardiopulmonary bypass on complex performed arterial grafts using this approach. In four patients, triple and quadruple vessel grafting was performed. RESULTS: No early deaths or postoperative complications occurred. The mean coronary clamp time was 12.5 +/- 5.1 minutes for the LAD, 10.8 +/- 1.8 minutes for diagonal branch, 14.1 +/- 2.9 minutes for the LCX and 16.0 +/- 5.1 minutes RCA time. There were no late deaths or angina during the mean follow-up of 37.3 +/- 9.0 months. Postoperative coronary angiography demonstrated widely patent grafts in all but one patient. Hemodynamics did not change significantly during the distal anastomoses. No wound-healing problems were experienced. CONCLUSIONS: Multiple MIDCABG using the figure L Approach represents a novel way of approaching both the LAD, CX and distal RCA in patients with multi-vessel disease, especially in those with low ejection fraction, huge heart (> CTR 50 %), or hemodynamically unstable patients, without any hemodynamic deterioration or sternal related complication.

Aged↗
PubMed2003

Effects of vitamin supplementation on microcirculatory disturbance in hemodialysis patients without peripheral arterial disease.

AIMS: Dysfunctional endothelium caused by oxidative stress is thought to play a role in pathogenesis of a variety of conditions including atherosclerosis. We investigated whether a microcirculatory disturbance in hemodialysis (HD) patients was associated with increased oxidative stress and endothelial injury. PATIENTS AND METHODS: Transcutaneous oxygen tension (TcPO2) on the dorsum of the foot at rest was measured as a marker of microcirculation in 33 patients undergoing HD without clinical manifestations of peripheral arterial disease and 20 healthy controls. Furthermore, in order to examine whether TcPO2 was affected by antioxidants, oral supplementation with a combination of vitamin C (200 mg daily) and vitamin E (600 mg daily) was administered for 6 months to 8 patients with microcirculatory disturbance (TcPO2 values of 50 mmHg or less). Serum biochemical parameters including vitamins were also measured. RESULTS: Mean TcPO2 value was significantly lower in HD patients than in control subjects (47.9 +/- 13.5 mmHg versus 62.4 +/- 11.9 mmHg, p < 0.001). After vitamin supplementation, TcPO2 values remarkably increased (40.6 +/- 10.0 mmHg versus 57.4 +/- 6.5 mmHg, p < 0.005). Serum vitamin C and vitamin E levels increased significantly as well, while serum levels of thrombomodulin, a marker of endothelial injury, and thiobarbituric acid reactants, a marker of lipid peroxidation, were significantly decreased in comparison with those before supplementation. CONCLUSIONS: Our results suggest that the microcirculatory disturbance in HD patients seems to be associated with endothelial damage caused by oxidative stress. Combined supplementation with vitamin C and vitamin E may be of clinical benefit in improving the cutaneous microcirculation by reducing oxidative stress.

Antioxidants↗
PubMed2002

Serosal application of Ba(2+) induces oscillatory chloride secretion via activation of submucosal cholinergic neurones in guinea-pig distal colon.

The enteric nervous system regulates ion and fluid secretion in the mammalian intestine at both resting and stimulated conditions. To determine the type and activation mechanism of neurones involved, mucosa-submucosa sheets isolated from guinea-pig distal colon were studied in vitro in Ussing chambers. Serosal addition of 0.5-1 mM barium (Ba(2+)), a potassium (K(+)) channel inhibitor, caused oscillatory increases in short-circuit current (I(sc)). Mean values of the size and frequency of I(sc) were 369.1 microA cm(-2) and 2.3 min(-1). The oscillatory I(sc) induced by the low concentrations of Ba(2+) was blocked by either higher concentrations of Ba(2+) (2-5 mM) or other K(+) channel inhibitors, such as tetraethylammonium (TEA) (1 mM) and quinine (20 mM). The Ba(2+)-induced oscillatory I(sc) was also inhibited by tetrodotoxin (TTX) and atropine. In a nominally Ca(2+) free solution plus serosal addition of 0.1 mM ethylene glycol-bis (beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA), a Ca(2+) chelator, the oscillatory I(sc) slowed and diminished. Further, the Ba(2+)-induced oscillatory I(sc) was partially inhibited by apical addition of 100 microM 5'-nitro-2-(3-phenylpropylamino)benzoic-acid (NPPB), a Cl(-) channel inhibitor, and completely disappeared in a low Cl(-) solution (11 mM) on both sides. On the other hand, application of either cimetidine, a histamine H(2) receptor antagonist, or hexamethonium, a nicotinic antagonist, to the serosal side did not affect the Ba(2+)-induced oscillatory I(sc). In conclusion, the Ba(2+)-induced oscillatory I(sc) is the transepithelial Cl(-) current which is stimulated by activation of cholinergic neurones in submucosal plexus of guinea-pig distal colon.

Animals↗
PubMed2001

A study of C-F...M(+) interaction: metal complexes of fluorine-containing cage compounds.

The C-F...M(+) interaction was investigated by observation of the NMR spectroscopic changes and complexation studies between metal cations and the cage compounds 1 and 2 which have fluorobenzene units as donor atoms. As a result, the interaction was detected with all of the metal cations which form complexes with 1 and 2. The stability of the complexes of 1 and 2 was determined by the properties of the metal cations (ionic radii and degree of hydrolysis), not by the hard-soft nature of the cations. Crystallographic analyses of Tl(+) subset 1 and La(3+) subset 2 provided structural information (interatomic distances and bond angles), and the bond strengths, C-F...M(+), O...M(+), and N...M(+), were estimated by Brown's equation based on the structural data. Short C-F...Tl(+) (2.952-3.048 A) distances were observed in the complex Tl(+) subset 1. The C-F bond lengths in the complexes, Tl(+) subset 1 and La(3+) subset 2, are elongated compared to those of the metal-free compounds. Interestingly, no solvent molecules including water molecules were coordinated to La(3+) in the La(3+) subset 2. The stabilization energy of cation-dipole interaction was calculated on the basis of the data from X-ray crystallographic analysis, and it is roughly consistent with the (-)Delta H values estimated in solution. Thus, the C-F...M(+) interaction can be expressed by the cation-dipole interaction. This result explains the fact that compound 1 which has fluorine atom as hard donor strongly binds soft metals such as Ag(+) and Tl(+). Furthermore, it was concluded that the fluorobenzene unit has a poor electron-donating ability compared to that of ether oxygen or amine nitrogen, and thus the ratio of the coordination bond in C-F...M(+) is small. The specific and remarkable changes in the (1)H, (13)C, and (19)F NMR spectra were observed accompanied by the complexation between M(+) and the hosts 1 and 2. These spectral features are important tools for the investigation of the C-F...M(+) interaction. Furthermore, F.Tl(+) spin couplings were observed at room temperature in the Tl(+) subset 1, 2 (J(F-Tl) = 2914 Hz for Tl(+) subset 1 and 4558 Hz for Tl(+) subset 2), and these are clear and definitive evidence of the interaction.

Journal Article↗
PubMed2001

Puromycin aminonucleoside induces apoptosis and increases HNE in cultured glomerular epithelial cells(1).

Puromycin aminonucleoside induces apoptosis and increases 4-hydroxy-2-nonenal (HNE) in cultured glomerular epithelial cells. We have previously reported the detachment of cultured glomerular epithelial cells (GECs) from their substrata by puromycin aminonucleoside (PAN) treatment. In this study we explored whether or not apoptosis was involved in the mechanisms of the detachment. DNA fragmentation on gel electrophoresis was clearly shown by 10(-3) M PAN treatment of GECs. Nuclear staining by Hoechst 33342 indicated the greatest number of apoptotic cells at 10(-3) M PAN for 48 h treatment. Similarly, TUNEL methods revealed maximal apoptotic cells at 10(-3) M PAN for 48 h treatment. Caspase-3 (like) protease activity increased at 10(-3) M PAN, and decreased at 2 x 10(-3) M PAN for 48 h treatment as well as at 10(-3) M PAN for 60 h treatment. Pretreatment with 2'-deoxycoformycin (DCF), inhibitor of adenosine deaminase, abolished these effects of PAN on cultured GECs. PAN treatment increased HNE, a lipid peroxide adduct, modified protein in cultured GECs, which was also prevented by pretreatment by DCF. These results for the first time indicate that the PAN-induced detachment of GECs from culture substrata is mediated at least in part through apoptosis via oxidative stresses by adenosine deaminase activity.

Adenosine Deaminase Inhibitors↗
PubMed2001

A study of C-F.M+ interaction: alkali metal complexes of the fluorine-containing cage compound.

The C-F.M(+) interaction was investigated by employing a cage compound 1 that has four fluorobenzene units. The NMR ((1)H, (13)C, and (19)F) spectra and X-ray crystallographic analyses of 1 and its metal complexes showed clear evidence of the interaction. Short C-F.M(+) distances (C-F.K(+), 2.755 and 2.727 A; C-F.Cs(+), 2.944 and 2.954 A) were observed in the crystalline state of K(+) subset 1 and Cs(+) subset 1. Furthermore, the C-F bond lengths were elongated by the interaction with the metal cations. By calculating Brown's bond valence, it is shown that the contribution of the C-F unit to cation binding is comparable or greater than the ether oxygen in the crystalline state. Representative spectroscopic changes implying the C-F.M(+) interaction were observed in the NMR ((1)H, (13)C, and (19)F) spectra. In particular, (133)Cs-(19)F spin coupling (J = 54.9 Hz) was observed in the Cs(+) complex.

Journal Article↗
PubMed2001

Simultaneous treatment with 1-beta-D-arabinofuranosylcytosine and daunorubicin induces cross-resistance to both drugs due to a combination-specific mechanism in HL60 cells.

We have established a human myelogenous leukemia cell line (HL60/AD) that is 10-fold cross-resistant to both 1-beta-D-arabinofuranosylcytosine (ara-C) and daunorubicin; the cell line was isolated from HL60 by simultaneous treatment with these two agents at low drug concentrations attainable in clinical trials. HL60/AD was found to have multiple resistance mechanisms. With regard to ara-C, HL60/AD cells showed decreased deoxycytidine kinase activity but did not show elevation of cytidine deaminase activity or a decrease in ara-C influx. With regard to daunorubicin, a decrease in topoisomerase II activity was found. A decrease in intracellular accumulation of daunorubicin was also found. P-glycoprotein was not detected, but the multidrug resistance-associated protein was expressed. Furthermore, an increase of total cellular glutathione (GSH) content was found. Interestingly, the resistance of HL60/AD cells not only to daunorubicin but also to ara-C was markedly reversed by treatment with L-buthionine-(S,R)-sulfoximine (BSO), a potent inhibitor of GSH synthesis. After exposure of HL60/AD to ara-C, mitochondrial membrane potential and reactive oxygen intermediates showed no significant change, but a considerable loss of mitochondrial membrane potential and an increase in reactive oxygen intermediate generation were caused by pre-incubation with BSO. Neither elevation of GSH nor reversal of resistance by BSO was found in ara-C-resistant HL60 cells that were selected only with ara-C. These findings suggest that in addition to the summation of the mechanisms of resistance to each agent reported previously, an increased level of GSH plays an important role in the cross-resistance induced in HL60/AD cells by simultaneous exposure to both drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Antimicrobial activity of everninomicin against clinical isolates of Enterococcus spp., Staphylococcus spp., and Streptococcus spp. tested by Etest.

The in-vitro antimicrobial activity of everninomicin, a novel oligosaccharide antibiotic, was tested against clinical isolates of 11 methicillin-susceptible Staphylococcus aureus (MSSA) strains, 11 methicillin-resistant S. aureus (MRSA) strains, 22 Staphylococcus epidermidis strains, 23 Enterococcus faecalis strains, 23 Enterococcus faecium strains, 23 Enterococcus avium strains, 27 Streptococcus pneumoniae strains, 22 Streptococcus pyogenes strains, and 20 Streptococcus agalactiae strains. The minimum inhibitory concentrations (MICs) of everninomicin were determined by Etest and compared with those of vancomycin, teicoplanin, and minocycline. The Etest showed that everninomicin exhibited excellent activity (MIC, <0.016 to 1.5 microg/ml) against the gram-positive cocci tested. The antimicrobial activity of everninomicin against S. aureus and S. epidermidis was stronger than that of vancomycin, teicoplanin, and minocycline, in particular against MRSA, with an MIC50 of 0.38 microg/ml and an MIC90 of 0.5 microg/ml. Against strains of enterococci and streptococci, everninomicin was more active than vancomycin, but as active as teicoplanin.

Aminoglycosides↗
PubMed2001

Characterization of MRSA transmission in an emergency medical center by sequence analysis of the 3'-end region of the coagulase gene.

The distribution of methicillin-resistant Staphylococcus aureus (MRSA) isolates at the St. Marianna University affiliated emergency medical center (EMC) was studied by sequence analysis of the 3'-end region of the coagulase gene. We collected a total of 42 MRSA isolates, consisting of 20 strains from the hospital environment, 13 strains from the nostrils or fingers of medical staff, and 9 strains from inpatients in the EMC. We compared our results with those from 27 stock strains of known coagulase serotype and 2 strains reported in the literature. All 69 strains tested have four to six tandem repeats in the 3'-end region of the coagulase gene. Among the 42 MRSA isolates collected, the base sequence of the 3'-end region of the coagulase gene was identical in 28 of them (67%). The number of isolates originating from the hospital environment, medical staff, and patients, respectively, that were identical to this representative strain were 18 (90%), 6 (46%), and 4 (44%). Phylogenetic analysis using the DNA sequences of the tandem repeat region demonstrated that almost all strains from the patients formed a concordant cluster with the representative strain from the hospital ward. We also assessed the value of sequence analysis of the 3'-end region of the coagulase gene as an epidemiological marker. Our results indicate that sequence analysis of the 3'-end region of the coagulase gene of MRSA may be a potent epidemiologic typing system.

Bacterial Typing Techniques↗