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Biomedical subjects

H Ishikawa

Publications and source records attributed to H Ishikawa.

At least 127 records · Page 7Linked to original sources
PubMed2001

[Effectiveness of a new toothbrush with irrigation and suctioning capabilities (ty e-Brush) for removing supragingival plaque].

Patients with dysphagia typically have poor oral health. Because of improper swallowing, they cannot easily and safely clean their mouths. As a solution for such a problem, a manual toothbrush with both irrigation and suctioning functions has been developed, called the "e-Brush". The purpose of this study was to evaluate the cleaning effectiveness of the new e-Brush (9 mm and 11 mm in bristle length) for removing supragingival plaque, compared with a conventional toothbrush, GUM # 211 by Butler. In this study, 12 subjects (12 female of average age 20.6) were selected, and plaque control record (PCR) and scrubbing method were used. The following results were obtained: 1. Significant differences (p < 0.05) were recognized between e-Brush/9 mm (55.54 +/- 18.27%) and the others (e-Brush/11 mm: 30.88 +/- 8.14%, GUM # 211: 35.42 +/- 9.32%). 2. Bristles 9 mm in length were more effective than 11 mm bristles (p < 0.05). 3. Irrigation/suctioning function is more effective than the conventional tooth-brushing method. 4. The irrigation function of e-Brush was meritorious in making almost all users comfortable. These results suggest that this new oral hygiene device, "e-Brush/9 mm", is effective for improving oral care management for patients with dysphagia.

Adult↗
PubMed2001

Coronary artery disease as a definitive risk factor of short-term outcome after starting hemodialysis in diabetic renal failure patients.

Cardiovascular disease is a major cause of morbidity and mortality in patients with diabetes who are receiving dialysis. It is known that cardiac mortality is high in the first year of hemodialysis (HD). The purpose of this study was to clarify the prevalence of coronary artery disease (CAD) in patients with diabetes at the initiation of HD, and to investigate the relationship between short-term outcomes after starting hemodialysis and CAD. We performed coronary angiography (CAG), whether or not patient had angina, within one month of initiation of maintenance HD in 17 of 34 consecutive unselected diabetic patients. We studied the two-year survival rate of those with CAD. Eleven patients (65%) were classified CAD-positive. Nine (82%) of these 11 had multivessel disease. Clinical and hematologic factors did not differ significantly between the groups with and without CAD. During the two-year follow-up period, 28 (82%) of 34 patients survived. In patients with CAD the two-year survival rate was 60%. None of the patients without CAD died within 2 years after starting HD. These results suggest that the presence of CAD at the initiation of HD may play a critical role in short-term outcomes after starting HD. We believe that an evaluation of CAD should be performed at the initiation of HD.

Chi-Square Distribution↗
PubMed2001

[Pitfall in the choice of the in situ arterial grafts in OPCAB].

Flow capacity with arterial grafts which have been used in off-pump CABG has been discussed. To analyze the hypoperfusion syndrome when in situ arterial grafts are selected, we made the simple mathematical model which consisted of two vessels with in parallel. We speculated the flow capacity of the various grafts, and flow distribution in the distal coronary artery, based on Poiseuille's law. This theoretical model clearly demonstrated that hypoperfusion syndrome occurred in reoperative coronary bypass grafting had a close relation with the diameters and lengths of bypass grafts.

Blood Viscosity↗
PubMed2001

[Presynaptic effects of botulinum toxin type A on the neuronally evoked response of albino and pigmented rabbit iris sphincter and dilator muscles].

PURPOSE: To investigate the effects of botulinum toxin type A(botulinum A toxin) on the autonomic and other non-adrenergic, non-cholinergic nerve terminals. METHODS: The effects of neurotoxin on twitch contractions evoked by electrical field stimulation (EFS) were studied in isolated rabbit iris sphincter and dilator muscles using isometric tension recording. RESULTS: Botulinum A toxin(150 nM) inhibited the fast cholinergic and slow substance P-ergic component of contraction evoked by EFS in the rabbit iris sphincter muscle without affecting the response to carbachol and substance P. Botulinum A toxin(150 nM) did not affect the twitch contraction evoked by EFS in the rabbit iris dilator muscle. CONCLUSION: These data indicated that botulinum A toxin may inhibit not only the acetylcholine release in the cholinergic nerve terminals, but also substance P release from the trigeminal nerve terminals of the rabbit iris sphincter muscle. However, neurotoxin has little effect on the adrenergic nerve terminals of the rabbit iris dilator muscle.

Animals↗
PubMed2001

Estrogenic influences of estradiol-17 beta, p-nonylphenol and bis-phenol-A on Japanese medaka (Oryzias latipes) at detected environmental concentrations.

Mature male medaka were continuously exposed to 0.005, 0.0-5 or 1.0 ppb of estradiol-17 beta (E2 or 0.1, 10 or 100 ppb of p-nonylphenol (NP) or bis-phenol-A (BPA). Female-specific proteins (Fsp) were induced in medaka exposed to 0.005 ppb of E2, 0.1 ppb of NP, or 10 ppb of BPA. Concentrations of 0.005 pbb of E2 and 0.1 ppb of NP corresponded to concentrations of these chemicals detected in river water in Japan. The abilities of the 3 chemicals to induce Fsp were E2 > NP > BPA. Embryonic medaka were exposed to E2, NP and BPA under conditions of static-renewal for 200-230 days until pre-maturity. Survival ratios of medaka exposed to E2 and NP declined in concentrations more than 25 ppb and 50 ppb, respectively. The groups of medaka exposed to E2 had individuals with testis-ova or abnormal gonad. There was no male in exposure to 1.0 ppb E2. When exposed to 100 ppb of NP or BPA, abnormal gonad was also detected. Abnormal anal fin (female-like) was observed in male exposed to 100 ppb of NP. The LC50 values for each of the 3 chemicals were much higher than the concentrations detected in water in the environment--the 3 chemicals were considered to have no lethal effect on medaka in aquatic environments. However, exposures to E2 or NP at environmental concentrations induced Fsp. BPA also had the ability to affect medaka as an environmental estrogen, although its extrogenic activity was weaker than that of E2 or NP.

Animals↗
PubMed2001

Evaluation of epithelial cell proliferation rate in normal-appearing colonic mucosa as a high-risk marker for colorectal cancer.

To determine whether the colonic epithelial proliferation rate is useful as a marker for colorectal cancer, we measured the Ki-67 labeling index (LI) in normal-appearing mucosa from the sigmoid and ascending colon in patients with two or more tumors (early cancers, which are defined as tumors the depth of invasion of which is limited to mucosal layer or submucosal layer, adenomas, or both). The association of baseline LI with the risk of development of colon tumors 2 years after endoscopic removal was assessed by cohort analysis. The presence of two or more tumors was defined as occurrence. One hundred and six specimens from the sigmoid colon and 130 from the ascending colon from 246 subjects (203 males and 43 females) were used for analysis. The patients with higher upper-third LI in the normal-appearing mucosa in the sigmoid colon, but not in the ascending colon, had significantly more tumors at follow-up colonoscopy 2 years later (risk ratio, 3.6; 95% confidence interval, 1.2-10.6). Moreover, multivariate analysis showed that it was an independent factor. We concluded that the higher upper-third Ki-67 LI of normal-appearing mucosa in the sigmoid colon indicates a high risk for colorectal cancer.

Adult↗
PubMed2001

[Sigmoid colon cancer with multiple liver metastasis (H3) effectively treated with CPT-11 and DSM (degradable starch microsphere) HAI therapy and intensive high dosage 5-FU HAI therapy--a case report].

A weekly HAI therapy (CPT-11 80 mg, MMC 4 mg, degradable starch microsphere (DSM) 600 mg) was given to a patient with sigmoid colon cancer and multiple liver metastasis (H3) who had been taking tegafur 300 mg/day and 5-FU 750 mg HAI/week, which resulted in PD. This therapy was carried out on an outpatient basis with minimum side effects (< grade 2). After 8 weeks, the tumor marker dropped to one tenth and the liver metastasis decreased in size (PR). The time courses of the concentrations of CPT-11, SN-38 and SN-38G were determined by drawing blood after HAI with or without DSM. The Cmax and AUC inf. of SN-38 at HAI without DSM were 17 ng/ml and 90.55 ng/h/ml, respectively, which was comparable to that at i.v. administration. The Cmax and AUC inf. of SN-38 at HAI with DSM were 12 ng/ml and 129.19 ng/h/ml, respectively, implying that DSM might have an enhancing effect on CPT-11 due to stasis of the hepatic artery that slows the conversion of CPT-11 to SN-38 resulting in a longer existence of SN-38.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

New approach for the establishment of mouse early embryonic stem cells and induction of their differentiation.

Eleven early embryonic stem (EES) cell lines were established using a new novel method. Two cell stage embryos from the ddY mouse strain were cultured in alpha-MEM supplemented with 10% fetal calf serum (FCS) and embryotrophic factors (ETFs) and allowed to develop to the trilaminal germ disc embryonic stage. Only small round cells (EES cells) were isolated by the colony isolating technique and subsequently cultured in the same medium containing the ETFs and leukemia inhibitory factors (LIF-10 ng/ml). The newly established embryonic stem (ES) cells isolated from inner cell mass of blastocysts differentiated from two cell stage embryo in culture. The EES and ES cell lines were maintained in an undifferentiated state using Ham's F12 medium supplemented with 10% FCS and 1 ng/ml of LIF. The EES cells maintained their normal genetic and morphological features as well as their potential to differentiate into a broad spectrum of cell types as well as their ability to contribute to all cell lineages in chimeric mice. Moreover, these cell lines changed and differentiated into various kinds of cells by removing LIF and by the addition of ETFs to the vitro culture system. All 11 EES cell lines and 3 ES cell lines formed embryoid bodies; however, cell line EES-4 formed tube-like structures which extended, anastomosed with each other, and finally formed networks when the LIF were absent. Primitive germ organ-like structures composed of 3 germ layers were recognized in the cultures following the administration of ETFs. In conclusion, the new method devised by us is a novel, easy and reliable technique for establishing EES cell lines.

Animals↗
PubMed2000

Analysis of cytogenetic and developmental effects on pre-implantation, mid-gestation and near-term mouse embryos after treatment with trichlorfon during zygote stage.

Trichlorfon has been widely used in agriculture as a broad spectrum insecticide. We examined cytogenetic and developmental effects on early mouse zygotes exposed to trichlorfon in vivo. Pregnant female mice were intraperitoneally administered a single dose of trichlorfon (100 or 200mg/kg) at 6h post presumed conception and either sacrificed on day of gestation (dg) 3, 9 or 17 to assess the developmental toxicity and mutagenic effects on embryos. Mean cell number (dg 3) and somite number (dg 9) of embryos in the two trichlorfon-treated groups were significantly fewer than in the control group and the mean micronucleus (MN) number (dg 3) and the frequency of mosaic aneuploidies including monosomic or trisomic cell lines (dg 9) was significantly increased in both trichlorfon-treated groups compared with the control group. However, there was no difference in fetal body weight (dg 17) between the control and trichlorfon-treated groups and no increased incidence of external malformations was observed in the trichlorfon-treated groups. These findings suggest that acute exposure of trichlorfon around fertilization induces a high frequency of MN, mosaic aneuploidies and developmental retardation in pre-implantation and mid-gestation embryos, and thereafter these embryos with MN or chromosome damage appear to develop past mid-gestation and catch up with normal embryos by near-term.

Abnormalities, Drug-Induced↗
PubMed2000

Effects of overexpression of Escherichia coli katE and bet genes on the tolerance for salt stress in a freshwater cyanobacterium Synechococcus sp. PCC 7942.

To explore the potential role of catalase and glycine betaine in the protection of cyanobacteria from damage due to salt stress, we transformed a freshwater cyanobacterium Synechococcus sp. PCC 7942 with shuttle vectors that contained the Escherichia coli katE, bet, and katE plus bet (katE/bet) genes. The catalase activity in the cells overexpressing katE and katE/bet genes was about 1.4-1.8-fold higher than that in the control cells. The control and transformant cells had a similar growth rate in the medium with a low salinity. However, under a high-salinity condition, the cells transformed with katE grew faster than the control cells, and the cells expressing katE/bet genes grew faster than those expressing either the katE or bet gene alone. These results indicate that high-salinity caused oxidative stress and the coexpression of katE and bet genes in Synechococcus cells were superior to the expression of either katE or bet alone for the protection of the cells from the damage due to high-salinity.

Journal Article↗
PubMed2000

Identification of histidine 77 as the axial heme ligand of carbonmonoxy CooA by picosecond time-resolved resonance Raman spectroscopy.

The heme proximal ligand of carbonmonoxy CooA, a CO-sensing transcriptional activator, in the CO-bound form was identified to be His77 by using picosecond time-resolved resonance Raman spectroscopy. On the basis of the inverse correlation between Fe-CO and C-O stretching frequencies, we proposed previously that His77 is the axial ligand trans to CO [Uchida et al. (1998) J. Biol. Chem. 273, 19988-19992], whereas later a possibility of displacement of His77 by CO with retention of another unidentified axial ligand was reported [Vogel et al. (1999) Biochemistry 38, 2679-2687]. Although our previous resonance Raman study failed to detect the Fe-His stretching [nu(Fe-His)] mode of CO-photodissociated CooA of the carbonmonoxy adduct due to the rapid recombination, application of the picosecond time-resolved resonance Raman technique enabled us to observe a new intense line assignable to nu(Fe-His) at 211 cm(-)(1) immediately after photolysis, while it became nondiscernible after 100-ps delay. The low nu(Fe-His) frequency of photodissociated CooA indicates the presence of some strain in the Fe-His bond in CO-bound CooA. This and the rapid recombination of CO characterize the heme pocket of CooA. The 211 cm(-)(1) band was completely absent in the spectrum of the CO-photodissociated form of the His77-substituted mutant but the Fe-Im stretching band was observed in the presence of exogenous imidazole (Im). Thus, we conclude that His77 is the axial ligand of CO-bound CooA and CO displaces the axial ligand trans to His77 with retention of ligated His77 to activate CooA as the transcriptional activator.

Bacterial Proteins↗
PubMed2000

Pepstatin A-sensitive aspartic proteases in lysosome are involved in degradation of the invariant chain and antigen-processing in antigen presenting cells of mice infected with Leishmania major.

We previously reported that CA074, a specific inhibitor of cathepsin B, significantly deviated immune responses from the disease-promoting Th2 type to the protective Th1 type in BALB/c mice infected with Leishmania major. Herein, we found that pepstatin A-sensitive aspartic proteases (PSAP) in lysosomes seem to play a different role from that of cathepsin B in antigen-processing and Ii-degradation. That is, cathepsin B appears to digest 16-, 28-, and 31-kDa peptides of soluble leishmania antigen (SLA), whereas PSAP seems to process mainly 28-kDa peptides. Furthermore, the latter protease contributed to the degradation of Ii but cathepsin B did not. Following treatment with pepstatin A, both Th1 and Th2 responses were profoundly suppressed in resistant DBA/2 mice (H-2(d)) and in susceptible BALB/c mice (H-2(d)), and both strains of mice became markedly susceptible compared with the untreated groups, probably owing to failure in degradation of Ii and partly to failure in digestion of 28-kDa peptide.

Animals↗
PubMed2000

Genome sequence of the endocellular bacterial symbiont of aphids Buchnera sp. APS.

Almost all aphid species (Homoptera, Insecta) have 60-80 huge cells called bacteriocytes, within which are round-shaped bacteria that are designated Buchnera. These bacteria are maternally transmitted to eggs and embryos through host generations, and the mutualism between the host and the bacteria is so obligate that neither can reproduce independently. Buchnera is a close relative of Escherichia coli, but it contains more than 100 genomic copies per cell, and its genome size is only a seventh of that of E. coli. Here we report the complete genome sequence of Buchnera sp. strain APS, which is composed of one 640,681-base-pair chromosome and two small plasmids. There are genes for the biosyntheses of amino acids essential for the hosts in the genome, but those for non-essential amino acids are missing, indicating complementarity and syntrophy between the host and the symbiont. In addition, Buchnera lacks genes for the biosynthesis of cell-surface components, including lipopolysaccharides and phospholipids, regulator genes and genes involved in defence of the cell. These results indicate that Buchnera is completely symbiotic and viable only in its limited niche, the bacteriocyte.

Aerobiosis↗