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Biomedical subjects

M Ishikawa

Publications and source records attributed to M Ishikawa.

At least 181 records · Page 10Linked to original sources
PubMed2000

[In vitro activities of carbapenem antibiotics against the various clinical isolates].

The annual changes of antibacterial activities of beta-lactam antibiotics, mainly carbapenem antibiotics, were investigated against 5 bacterial species, S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, which had been isolated from the clinical materials at Toho University Omori Hospital during the period of 1995 to 1997. In addition, antibacterial activities against other main bacterial strains isolated from the clinical materials during 1997 were also determined. The five bacterial species on which annual changes of the sensitivity were investigated did not show any remarkable trend to increase in resistance to the carbapenem antibiotics tested. The antibacterial activities of the carbapenem antibiotics against MRSA were weak, and MIC90 values were between 25 and 50 micrograms/ml. In S. marcescens and P. aeruginosa on which high resistance by the production of metallo-beta-lactamase has become a problem in recent years, there were no remarkable changes in annual changes of sensitivities. Especially, MIC90 valuses of the carbapenem antibiotics against P. aeruginosa were between 12.5 and 25 micrograms/ml, 4 to 8 times better than that of PIPC, like the case of CAZ. Furthermore, the carbapenem antibiotics showed strong antibacterial activities against clinically important 16 bacterial species, from Gram-positive to Gram-negative bacteria.

Carbapenems↗
PubMed2000

[The comparison of sensitivity between immunostaining and a simplified PCR-cold SSCP method in p53 genomic mutations].

The PCR-SSCP (single strand conformational polymorphism) method has been widely employed to screen mutations in a variety of genes because of its rapidity and simplicity in the operation. Using this method, we have examined mutations of some tumor-related genes including p53 and Ki-ras. In this study, we have evaluated the PCR-Cold (non radioactive) SSCP method for detection of p53 point mutations in comparison with immunohistological detection of p53 and PCR-direct sequencing. The results indicated that the PCR-Cold SSCP method had the same sensitivity with that of PCR-direct sequencing method, and had higher sensitivity than that of immunohistochemical method (IHC).

Genes, p53↗
PubMed2000

Endogenous nitric oxide proves not to be involved in the inhibition by IL-1beta of TGF-alpha-stimulated proliferation of RGM1 cells.

Combined treatment of isolated rat gastric mucosal (RGM1) cells with interleukin (IL)-1beta and transforming growth factor (TGF)-alpha resulted in expression of inducible nitric oxide synthase (iNOS) mRNA and iNOS protein 24 hr after the treatment. Constitutive NOS (nNOS) protein was not proved in the cells and not activated by IL-1beta+TGFalpha. Although IL-1beta and TGF-alpha alone exerted little or no effect on NO2 production, their combination gradually increased NO2- production from 12 to 24 hr following treatment. NO2- production stimulated by IL-1beta + TGFalpha was significantly reduced by N(G)-nitro-L-arginine methyl ester (L-NAME) or aminoguanidine, yet not by D-NAME. S-nitroso-N-acetyl-D,L-penicillamine and sodium nitropruside significantly inhibited both spontaneous and TGF-alpha stimulated DNA synthesis. Nonetheless, L-NAME did not affect the inhibition by IL-1beta of TGF-alpha-stimulated proliferation of RGM1 cells, eliminating the possibility of involvement of NO in the underlying mechanisms.

Animals↗
PubMed2000

[Characteristics of functional training and effects on physical activities of daily living].

PURPOSE: The effects of functional training on physical Activities of Daily Living (ADL) based on the Health and Medical Service Law for the Elderly have been controversial. The aim of the present study was to explore its characteristics and influence with a large sample. SUBJECTS AND METHODS: 669 participants and 1,110 non-participants in functional training were recruited from 54 cities and villages in 1998. The effects of functional training on physical ADL were evaluated by comparing the baseline ADL and 1-year follow-up ADL in the "index of Activities of Daily Living for bedridden elderly (1993)". RESULTS: 1. The change in physical ADL in participants was significantly better than that in non-participants after adjusting for age. 2. Significant effects of functional training were observed in both sexes, in all three age groups, and in ranks J, A and B. 3. There was no significant difference between the sexes in terms of the influence of functional training. Functional training was more effective in the younger group, in stroke subjects, and individuals suffering from any disease within one year prior to the baseline. 4. A total of 16.4% of the participants demonstrated increased physical ADL, while 7.2% of the participants also had increased mobility. CONCLUSION: Functional training has a significant positive effect on increase of physical ADL. Functional training based on the Health and Medical Service Law for the Elderly is an effective program especially for homebound and/or frail people who are at risk of becoming bedridden. Further longitudinal studies are now needed to improve functional training for increasing ADL and QOL.

Activities of Daily Living↗
PubMed2000

Can three-dimensional helical CT cholangiography before laparoscopic cholecystectomy be a substitute study for endoscopic retrograde cholangiography?

The study investigated the usefulness of three-dimensional helical computed tomography (3D-CT) before laparoscopic cholecystectomy (LSC) when compared with that of endoscopic retrograde cholangiography (ERC). Forty-five patients referred for LSC, who had undergone 3D-CT cholangiography and ERC simultaneously, participated in the study. Endoscopic retrograde cholangiography and 3D-CT cholangiography were compared in each patient with regard to opacification of the biliary tree, stones, and anatomic variations. Three-dimensional helical CT cholangiography and ERC imaging for predicting operative difficulties in LSC also were compared. The common bile duct and cystic duct were shown in the patients by the images, but the gallbladder was shown in 43 patients (96%) with use of 3D-CT cholangiography and in 36 patients (80%) with use of ERC. A third or more peripheral branches were shown completely with use of 3D-CT cholangiography in 33 patients (73%) and in 32 patients (71%) with use of ERC. Cystic duct stones were found in two of three patients with use of 3D-CT cholangiography and ERC. Common bile duct stones in five of seven patients were detected with use of 3D-CT cholangiography, but all of the common bile duct stones were detected with use of ERC. Anatomic variations of the bile duct were shown in three of four patients by 3D-CT cholangiography and in all patients with use of ERC. No significant differences in findings of the angle of bifurcation and presence of Heister valves between operative easy and complex cases were shown by 3D-CT cholangiography and ERC, despite the more accurate assessment of the cystic duct anatomy with use of 3D-CT cholangiography than with use of ERC. Three-dimensional helical CT cholangiography is useful clinically in preoperative assessment of biliary anatomy, but it is not reliable in the detection of common bile duct stones, and it is not helpful in predicting technical difficulty during LSC.

Adult↗
PubMed2000

[Habitual abortion and high frequency of low frequent X chromosome monosomy mosaicism: detection by interphase FISH analysis of buccal mucosa cells and lymphocytes].

FISH analysis using X alpha satellite probe was performed to the nuclei of lymphocytes obtained from fourteen women with having a history of habitual abortion for unknown causes(WHA) and from 65 normal control women(NW), in order to determine whether low frequency X monosomy mosaicism is one of the factors of habitual abortion. In parallel, the nuclei of buccal mucosa from 8 of WHA and 65 NW were also examined. Five hundreds of the interphase nuclei in each sample were observed. As results, the frequency of X monosomy in NW found in the lymphocytes or buccal mucosa was ranged from 0-3.2%(mean 1.59%, SD 0.69%) or from 0-3.2%(mean 1.24%, SD 0.85%), respectively. However, the occurrence of X monosomy in WHA was significantly higher compared with that of NW; i.e., 0.8-5.8%(mean 3.21%, SD 1.67) for lymphocytes, and 1.8-7.4%(mean 4.45%, SD 1.73%) for buccal mucosa. These results allowed us to define the reference intervals to discriminate WHA from NW were less than 2.97% or 2.94% for lymphocytes or buccal mucosa, respectively. Based on the reference intervals defined above, the high frequency of X monosomy mosaicism was actually found in 9 of 14 WHA. These results altogether strongly suggested that the low frequency X monosomy mosaicism was one of the factors of habitual abortion.

Abortion, Habitual↗
PubMed2000

Free-flow isotachophoresis under micro-gravity.

When free flow electrophoresis (FFE) is applied to the separation and purification process under microgravity, higher separability is expected than that under usual 1 G environment, because sedimentation of samples and heat convection can be neglected. Although FFE under micro-gravity is a very important technique for efficient separation of macromolecules because of the above merits, FFE unit (FFEU) should be more sophisticated to give stable operation, high separability, high through-put and high separation efficiency. In this study, fundamental research to achieve FFE with such high performance was done by using a commercial FFEU. The research contains (1) the quantitative study on the separation mode of FFE and separation efficiency, (2) the feasibility analysis of free-flow bidirectional isotachophoresis (FFBITP) which enables separation of cations anions simultaneously by isotachophoresis (ITP) and zone electrophoresis (ZE), (3) the optimization of hardware factors such as thickness of the separation chamber which may cause deterioration of separation due to heat convection, and (4) the analysis of hardware factors depending on the long-time operation. The ultimate goal of this study is to obtain fundamental data for the development of FFE for the international space station. In this paper, the experimental results obtained in a reduced-gravity aircraft was mainly.

Electrophoresis↗
PubMed1999

Evidence for autoregulation of cystathionine gamma-synthase mRNA stability in Arabidopsis.

Control of messenger RNA (mRNA) stability serves as an important mechanism for regulating gene expression. Analysis of Arabidopsis mutants that overaccumulate soluble methionine (Met) revealed that the gene for cystathionine gamma-synthase (CGS), the key enzyme in Met biosynthesis, is regulated at the level of mRNA stability. Transfection experiments with wild-type and mutant forms of the CGS gene suggest that an amino acid sequence encoded by the first exon of CGS acts in cis to destabilize its own mRNA in a process that is activated by Met or one of its metabolites.

Amino Acid Sequence↗
PubMed1999

Inhibitory effect of macrophage-derived factors on the recovery of wounds induced in rat gastric epithelial monolayers.

The effect of macrophage supernatant on the recovery of wounds induced in rat gastric epithelial RGM1 monolayers was investigated. The repair of wounds induced in the monolayers of RGM1 cells was accelerated time-dependently by 10 ng/mL of transforming growth factor-alpha (TGF-alpha). TGF-alpha also significantly stimulated DNA synthesis in RGM1 cells for 24 hr. Upon treatment of the cells with the macrophage supernatant, spontaneous and TGF-alpha-stimulated restoration was inhibited in a time- and concentration-dependent manner. After 24 hr, TGF-alpha-enhanced restoration was eliminated completely by the supernatant at 10(6) cells/mL. Similarly, the macrophage supernatant suppressed the spontaneous and TGF-alpha-stimulated DNA syntheses in a concentration-dependent manner. The macrophage supernatant at 10(6) cells/mL contained 0.4 ng/mL of interleukin-1beta (IL-1beta). Interleukin-1 receptor antagonist (IL-1RA) reversed the inhibition induced by the macrophage supernatant in a concentration-dependent manner. Nonetheless, pretreatment with IL-1RA had no effects on the spontaneous and TGF-alpha-stimulated DNA syntheses. Reverse transcription-polymerase chain reaction analysis revealed that RGM1 cells express mRNA for IL-1 receptor type 1, but not for type 2. These results indicate that macrophages can inhibit the spontaneous and TGF-alpha-stimulated recovery of wounds induced in gastric epithelial monolayers. The inhibitory effects of the supernatant are suggested to be partially mediated through a IL-1beta/IL-1 receptor type 1 pathway.

Animals↗
PubMed1999

Upregulation of endogenous heparin-binding EGF-like growth factor and its role as a survival factor in skeletal myotubes.

To investigate the role of heparin-binding EGF-like growth factor (HB-EGF) in skeletal muscle, we studied its function in skeletal myotubes in vitro using mouse C2C12 cells. Expression levels of membrane-anchored HB-EGF (proHB-EGF) protein were increased specifically during their differentiation among epidermal growth factor receptor (EGFR) ligands. Production levels of EGFR on the cell surface were constant. Tyrosine phosphorylation of EGFR, however, was constitutively increased during differentiation. Quenching of endogenous HB-EGF significantly rendered myotubes sensitive to apoptotic cell death induced by hypoxic stress, suggesting that proHB-EGF in the skeletal muscle is specifically upregulated to function as a survival factor.

Animals↗
PubMed1999

Involvement of cardiotrophin-1 in cardiac myocyte-nonmyocyte interactions during hypertrophy of rat cardiac myocytes in vitro.

BACKGROUND: The mechanism responsible for cardiac hypertrophy is currently conceptualized as having 2 components, mediated by cardiac myocytes and nonmyocytes, respectively. The interaction between myocytes and nonmyocytes via growth factors and/or cytokines plays an important role in the development of cardiac hypertrophy. We found that cardiac myocytes showed hypertrophic changes when cocultured with cardiac nonmyocytes. Cardiotrophin-1 (CT-1), a new member of the interleukin-6 family of cytokines, was identified by its ability to induce hypertrophic response in cardiac myocytes. In this study, we used the in vitro coculture system to examine how CT-1 is involved in the interaction between cardiac myocytes and nonmyocytes during the hypertrophy process. METHODS AND RESULTS: RNase protection assay revealed that CT-1 mRNA levels were 3. 5 times higher in cultured cardiac nonmyocytes than in cultured cardiac myocytes. We developed anti-CT-1 antibodies and found that they significantly inhibited the increased atrial and brain natriuretic peptide secretion and protein synthesis characteristic of hypertrophic changes of myocytes in the coculture. In addition, non-myocyte-conditioned medium rapidly elicited tyrosine phosphorylation of STAT3 and induced an increase in natriuretic peptide secretion and protein synthesis in cultured cardiac myocytes; these effects were partially suppressed by anti-CT-1 antibodies. Finally, the hypertrophic effects of CT-1 and endothelin-1, which we had previously implicated in the hypertrophic activity in the coculture, were additive in cardiac myocytes. CONCLUSIONS: These results show that CT-1 secreted from cardiac nonmyocytes is significantly involved in the hypertrophic changes of cardiac myocytes in the coculture and suggest that CT-1 is an important local regulator in the process of cardiac hypertrophy.

Animals↗
PubMed1999

Effects of ortho-substituent groups of sulochrin on inhibitory activity to eosinophil degranulation.

Sulochrin, a metabolite of fungi, has been shown to have an inhibitory activity to eosinophil degranulation. A series of sulochrin derivatives substituted at ortho-positions to the 10-carbonyl group was examined the activity. The importance of alkylester at C-6 position and several chemical properties of substituted groups at ortho-positions to exhibit activity are described.

Anti-Allergic Agents↗
PubMed1999

1,3-Disubstituted benzazepines as novel, potent, selective neuropeptide Y Y1 receptor antagonists.

A novel series of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Chemical modification of the R(1) and R(3) substituents in structure 1 (Chart 1) yields several compounds that show high affinity for the Y1 receptor (K(i) values of less than 10 nM). SAR studies revealed that introduction of an isopropylurea group at R(1) and a 3-(benzo-condensed-urea) group, 3-(fluorophenylurea) group, or a 3-(N-(4-hydroxyphenyl)guanidine) group at R(3) in structure 1 afforded potent and subtype-selective NPY Y1 receptor antagonists. 3-(3-(Benzothiazol-6-yl)ureido)-1-N-(3-(N'-(3-isopropylureido++ +))benzyl )-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (21), which was one of the most potent derivatives, competitively inhibited specific [(125)I]peptide YY (PYY) binding to Y1 receptors in human neuroblastoma SK-N-MC cells (K(i) = 5.1 nM). 21 not only inhibited the Y1 receptor-mediated increase in cytosolic free Ca(2+) concentration in SK-N-MC cells but also antagonized the Y1 receptor-mediated inhibitory effect of peptide YY on gastrin-induced histamine release in rat enterochromaffin-like cells. 21 showed no significant affinity in 17 receptor binding assays including Y2, Y4, and Y5 receptors.

Animals↗
PubMed1999

Proliferation of neuronal precursor cells in the dentate gyrus is accelerated after transient forebrain ischemia in mice.

We investigated the proliferation of neuronal progenitor cells by labeling dividing cells by systemic application of the thymidine analog 5-bromodeoxyuridine (BrdU) during transient forebrain ischemia in mice. At 3 (n=6), 7 (n=6), 10 (n=6), and 17 days (n=6) after reperfusion, BrdU-labeled cells were detected in the dentate gyrus and paraventricle lesion. After ischemia-reperfusion, BrdU-labeled cells in the dentate gyrus significantly increased in number but not in the paraventricle lesion. These observations may help to clarify the mechanism of functional recovery after stroke.

Animals↗
PubMed1999

Mechanisms of recovery from experimental allergic encephalomyelitis induced with myelin basic protein peptide 68-86 in Lewis rats: a role for dendritic cells in inducing apoptosis of CD4+ T cells.

Spontaneous remission of experimental allergic encephalomyelitis (EAE) is usually associated with prominent apoptosis. The mechanisms behind apoptosis are unknown. We examined the functions of dendritic cells (DC) from Lewis rats with EAE induced by immunization with myelin basic protein peptide 68-86 (MBP68 - - 86). Recovery from EAE was associated with three major functional changes of freshly prepared DC: (1) elevated proliferation, (2) increased nitric oxide (NO) production, and (3) augmented IFN-gamma secretion. In Freund's complete adjuvant (FCA)-immunized control rats, no increase of proliferation, NO production or IFN-gamma secretion was observed on day 21 post-immunization (p.i.), i.e., recovery from EAE. In vitro effects of IFN-gamma, TNF-alpha, TGF-beta1, IL-4 and IL-10 on DC were examined. IFN-gamma enhanced proliferation and NO production by DC, while TNF-alpha and IL-4 induced only slight DC proliferation. DC from recovering EAE rats (day 21 p.i.) suppressed MBP68 - - 86-induced T cell proliferation compared to DC obtained at other time points in EAE and FCA-immunized rats. DC-derived NO induced apoptosis of CD4+ T cells, thereby inhibiting autoreactive T cell responses. Besides IFN-gamma stimulation, NO production by DC was mainly induced in an antigen-dependent manner when DC were co-cultured with T cells. The results suggest that spontaneous recovery from EAE is associated with augmented DC functions. Overproduction of NO by DC results in apoptosis of autoreactive CD4+ T cells, thereby decreasing autoreactive T cell reactivities. The existence of such a NO negative feedback loop may contribute to remission of EAE.

Animals↗
PubMed1999

Requirement of sperm-oocyte plasma membrane fusion for establishment of the plasma membrane block to polyspermy in human pronuclear oocytes.

We investigated whether the incorporation of the sperm membrane into the oolemma contributes to the human plasma membrane block to polyspermy. We used zona pellucida-free oocytes fertilized by intracytoplasmic sperm injection (ICSI) or activated by parthenogenetic activation. Only two of the 35 pronuclear oocytes fertilized by spermatozoa (control) demonstrated one single penetrating spermatozoa. In contrast, the majority of ICSI and parthenogenetically activated pronuclear oocytes were penetrated with an average of three spermatozoa per oocyte. The number of fused and binding spermatozoa of ICSI and parthenogenetically activated oocytes were significantly higher than in control oocytes (3.5+/-0.6 and 4.3+/-0.6 for ICSI; 3.0+/-0.3 and 3.8+/-0.4 for activated and 0.2+/-0.1 and 0.6+/-0.2 for controls, respectively, P < 0.01). Furthermore, the cortical granules were released from the cortex of ICSI and calcium ionophore-puromycin-activated pronuclear oocytes to the same extent as that of pronuclear oocytes fertilized by spermatozoa. These results suggest that the establishment of the plasma membrane block to sperm penetration in the human oocyte may require a fusion process between sperm and oocyte plasma membranes.

Cell Membrane↗
PubMed1999

31P NMR studies of phosphate metabolism in the ovulatory process induced by gonadotropins in perfused rabbit ovary.

The concentrations of phosphate metabolites were measured in perfused rabbit ovaries before, during and after ischemia, and during the ovulatory process induced by the administration of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG) using 31P NMR spectroscopy. A decrease in adenosine triphosphate (ATP) and an increase in inorganic phosphate (Pi) during ischemia were observed. After reperfusion of the ovary, both ATP and Pi levels returned to their initial control levels. These results are in agreement with the results observed in other organ tissues. On the other hand, ATP levels rapidly decreased dose dependently with infusion of HCG during 10 h of perfusion. A decrease in ovarian ATP concentration after infusion of HCG was also confirmed by enzymatic analysis of the extracts from ovarian tissues. On the other hand, significant changes in Pi levels were not observed throughout the perfusion period. Furthermore, significant changes in phosphomonoester (PME) levels, adenosine diphosphate (ADP) levels and intracellular pH were not observed before and during the infusion of HCG. The concentration of cyclic adenosine 3',5'-monophosphate (cAMP) in the perfusate after the perfusion was also measured during the ovulatory period. Within 30 min cAMP significantly increased dose dependently and reached peak levels within 60 min. The concentration of cAMP then gradually decreased. Ovulatory efficacy during the infusion of HCG was also observed. These results suggest that the decreased ATP in the successive processes leading to ovulation probably reflects protein phosphorylation through the activation of the cAMP-dependent protein kinases prior to induction of various chemical reactions related to the initiation of ovulation.

Adenosine Triphosphate↗