Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 127 records · Page 7Linked to original sources

PubMed2001

Antibacterial activity of essential oils and their major constituents against respiratory tract pathogens by gaseous contact.

The antibacterial activity of 14 essential oils and their major constituents in the gaseous state was evaluated against Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus. For most essential oils examined, H. influenzae was most susceptible, followed by S. pneumoniae and S. pyogenes, and then S. aureus. Penicillin-susceptible and -resistant S. pneumoniae were comparable in susceptibility. Escherichia coli, which was used as a control, showed least susceptibility. A minimal inhibitory dose (MID) was introduced as a measure of the vapour activity. Among 14 essential oils, cinnamon bark, lemon-grass and thyme oils showed the lowest MID, followed by essential oils containing terpene alcohols as major constituents. The essential oils containing terpene ketone, ether and, in particular, hydrocarbon had high MIDS. The vapour activity on short exposure was comparable to that following overnight exposure, and rapid evaporation was more effective than slow evaporation of essential oils. The vapour concentration and absorption into agar of essential oils reached a maximum 1 or 2 h after rapid evaporation. These results indicate that the antibacterial action of essential oils was most effective when at high vapour concentration for a short time.

Anti-Bacterial Agents↗

PubMed2001

Synergy of lysozyme and lanoconazole on the morphology of Candida albicans.

Synergism of lysozyme with the imidazole antifungal lanoconazole (LCZ) has been demonstrated in vitro against Candida albicans. To determine the mechanism of the synergistic action, the effects of subinhibitory concentrations of lysozyme (50 microg ml(-1)) and LCZ (1.25 microg ml(-1)), used alone and in combination, on the morphology and ultrastructure of C. albicans cells were studied by fluorescence microscopy using Fungiflora Y, as well as by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the presence of lysozyme, the separation of apparently mature cells from each other was inhibited, and cells in which cell wall-like material had markedly accumulated in the periplasmic space were frequently observed. Such intracellular ultrastructural changes were not seen in LCZ-treated cells, but normal septal wall biogenesis was inhibited with the resultant formation of long chains of interconnecting cells. When the cultures were treated with the combination of lysozyme and LCZ, intracellular accumulation of cell wall-like materials increased in extent, and the peripheral wall structure was severely damaged. These morphological and ultrastructural findings lead us to the following conclusions: (1) lysozyme and LCZ inhibit the process of cell division in different manners; (2) lysozyme appears to affect cell wall formation more directly and drastically by interrupting the normal assembly and integration of cell wall components; and (3) these effects of lysozyme are noticeably enhanced when combined with LCZ.

Antifungal Agents↗

PubMed2001

Alzheimer beta amyloid deposition enhanced by apoE epsilon4 gene precedes neurofibrillary pathology in the frontal association cortex of nondemented senior subjects.

To clarify how Alzheimer disease pathology develops in the brains of nondemented subjects, we examined the interrelations among the amounts and morphology of Abeta deposition, neurofibrillary pathology, and apolipoprotein E (ApoE) genotype in the frontal association cortex of 101 autopsy brains from patients aged between 40 to 83. Senile plaque density correlated well with the logarithmic data of insoluble Abeta measured by enzyme immunoassay (EIA). The amounts of Abeta42-ETA increased dramatically in the late preclinical stage, whereas the AP42+ plaque density increased in the early preclinical stage. Neurofibrillary pathology appeared only in the areas with severe Abeta deposition and in subjects aged over 70. The ApoE epsilon4 allele enhanced the Abeta3 deposition in presenile subjects. Plaque-associated glial Abeta was prominent in subjects with mild to moderate Abeta deposition. The morphology of cerebral Abeta deposition changed from diffuse plaques with small amounts of Abeta in each plaque in the early preclinical stage to primitive/neuritic plaques with larger amounts of Abeta in each plaque in the late preclinical stage. Our findings suggest that the prevention of Abeta deposition in the late preclinical stage can be a rational therapeutic target, especially in elderly people with ApoE epsilon4 allele.

Adult↗

PubMed2001

Side chain effect on ion channel characters of Aib rich peptides.

As models of ion channel proteins and naturally occurring pore-forming peptides, we designed a series of Aib rich peptides [Ac-(Aib-Xxx-Aib-Ala)(5)-NH(2) (Xxx = Lys, Glu, Ser, and Gly: BXBA-20)] to investigate the effects of the side chains of the amino acid residues Lys, Glu, Ser, and Gly on the conformation and electrophysiological properties of ion channels. The conformation of peptides and their affinity for phospholipid membranes were evaluated by CD spectroscopy. Patch-clamp experiments revealed that all BXBA-20 peptides form ion channels in DPhPC bilayers exhibiting clearly resolved transitions between the open and closed states. The channel forming frequency was in the order BKBA-20>BEBA-20>BSBA-20>BGBA-20. In the case of BKBA-20 and BEBA-20, the self-assembled conductive oligomers expressed homogeneous and voltage-independent single channel conductances. In contrast, heterogeneous conductance was observed in BSBA-20 and BGBA-20 ion channels under similar experimental conditions. From these results, we conclude that peptides with a high degree of helical conformation, high amphipathicity, high affinity for lipid membranes, and self-associating characters in vesicles are most suitable for inducing ion channels with a high frequency of occurrence. Moreover, BEBA-20, BSBA-20, and BGBA-20 channels were cation-selective, whereas the BKBA-20 channel was non-selective.

Aminoisobutyric Acids↗

PubMed2001

Differential dosimetry in a neutron-proton mixed field with low-pressure proportional counters.

For a mixed radiation field of neutrons and protons, radiation events were discriminated between photons, neutrons, and protons using a thin plastic scintillator. Distributions of lineal energy were measured with low-pressure proportional counters (LPPCs). To estimate the distribution of lineal energy for ICRU muscle, measurements were carried out using A-150-walled, graphite-walled, ZrO2-walled, and Zr-walled counters. Data were corrected for different atomic compositions between the A-150 plastic and ICRU muscle.

Energy Transfer↗

PubMed2001

Personal identification using Y-chromosomal short tandem repeats from bodily fluids mixed with semen.

The male-specific, human Y-chromosomal short tandem repeats (Y-STRs) are very useful in forensic analysis. The authors report a sexual crime case in which the direct Y-STR haplotype analysis of several mixtures of various bodily fluids including semen was very effective for identifying the perpetrator of the crime. The typing of three Y-STRs (DYS19, DYS389II, and DYS390) could be detected from the mixed DNA of sperm and female cells in the victim's vagina, vaginal orifice, and anus. These haplotypes originated from one man and matched those of the suspect. Accordingly, the combination of direct extraction of DNA and Y-STR haplotype analysis is considered to be very useful for mixtures of bodily fluids, including semen or other male cells.

Adult↗

PubMed2001

Preoperative small-dose ketamine prevented tourniquet-induced arterial pressure increase in orthopedic patients under general anesthesia.

UNLABELLED: The mechanism of tourniquet-induced arterial pressure increase is not known. We investigated the effect of preoperative ketamine on tourniquet-induced arterial pressure and heart rate changes in 85 patients undergoing knee surgery with a tourniquet under general anesthesia. Patients were randomly assigned into three groups; Large Ketamine (n = 28; ketamine 1.0 mg/kg), Small Ketamine (n = 28; ketamine 0.25 mg/kg), and Control (n = 29; normal saline) groups. Anesthesia was maintained with 1.5%-2.5% sevoflurane and 66% N(2)O in oxygen with endotracheal intubation. Ketamine or normal saline was given in a double-blinded fashion before skin incision and tourniquet inflation. Arterial pressure and heart rate were recorded every 10 min until 60 min after the start of tourniquet inflation and again after deflation. Arterial pressure and heart rate were compared among the three groups by using repeated-measures analysis of variance. In the Large and Small Ketamine groups, arterial pressure was not significantly changed, but in the Control group arterial pressure was significantly increased 40, 50, and 60 min after the start of tourniquet inflation (P < 0.05). Development of more than a 30% increase in systolic arterial pressure during tourniquet inflation was more frequent in the Control group than the other groups. The results show that preoperative IV ketamine, 0.25 mg/kg or more, significantly prevented tourniquet-induced systemic arterial pressure increase in patients under general anesthesia. IMPLICATIONS: Preoperative small-dose ketamine, IV, significantly prevented a systemic arterial pressure increase during prolonged tourniquet inflation in patients under general anesthesia.

Adolescent↗

PubMed2001

Effect of sealing and Tween 80 on the antifungal susceptibility testing of essential oils.

Concentrations of essential oils showing high volatility decreased substantially in broth and agar media when incubated under open conditions. The decrease in the half life was from 0.7 to 38 hr in broth medium at 27 C. When evaporation was prevented by sealing, MIC values against Aspergillus fumigatus, Candida albicans and Trichophyton mentagrophytes by broth or agar dilution assay were lowered two to eight-fold, as compared with those obtained under open conditions. Addition of Tween 80 caused a rise of the MICs against A. fumigatus by two to four-fold in broth dilution assay, but little affected the MICs in agar dilution assay.

Antifungal Agents↗

PubMed2001

Cluster analysis of human and animal pathogenic Microsporum species and their teleomorphic states, Arthroderma species, based on the DNA sequences of nuclear ribosomal internal transcribed spacer 1.

We performed a cluster analysis of human and animal pathogenic Microsporum species and their teleomorphic states, Arthroderma species, including A. otae-related species (M. canis, M. audouinii, M. distortum, M. equinum, M. langeronii, and M. ferrugineum) and M. gypseum complex (A. fulvum, A. gypseum, and A. incurvatum) using DNA sequences of nuclear ribosomal internal transcribed spacer 1 (ITS1). The dendrogram showed the members of A. otae-related species to be monophyletic and to construct an extremely closely related cluster with a long horizontal branch. This ITS1-homologous group of A. otae was organized in 6 unique genotypes, while sequences of the members of the ITS1-homologous group of M. gypseum complex are more diverse. This ITS1-based database of Microsporum species and their teleomorphic states will provide a useful and reliable species identification system: it is time-saving (takes two to three days), accurate and applicable even to strains with atypical morphological features or in a non-culturable state.

Animals↗

PubMed2001

Fungal flora on board the Mir-Space Station, identification by morphological features and ribosomal DNA sequences.

This report is on the morphological and molecular biological identification, using 18S- and ITS1-rDNA sequences, of the "space fungi" isolated on board the Russian Mir-Space Station as the major constituents of the fungal flora. The six fungal strains were isolated from air by using an air sampler or from condensation. Strains were identified as Penicillium chrysogenum, Aspergillus versicolor, or Penicillium sp. by both methods. The species of space fungi were common saprophytic fungi in our living environment, potential pathogens, and allergens. This study concluded that the environment on board the space station Mir allows the growth of potentially pathogenic fungi as true in residential areas on the earth. Therefore, to prevent infection or other health disorders caused by these fungi, easy and reliable methods should be established to survey the fungal flora in a space station.

Aspergillus↗

PubMed2001

[Suppressive effect of lansoprazole on anti-Candida activity of murine macrophages].

This study investigated the influences of lansoprazole (AG1749), a proton pump inhibitor (PPI), and its active derivative (AG2000) on Candida albicans growth and the anti-Candida activity of macrophages. Under concentration of 100 microM, AG1749 and AG2000 had no effect on Candida growth. Murine peritoneal macrophages inhibited the growth of C. albicans in vitro. AG2000 suppressed the anti-Candida activity of macrophages dose-dependently, but AG1749 didn't. The suppressing activity of AG2000 for macrophages was neutralized by adding a SH-compound (L-cysteine) in the medium. This suggests that AG2000 may suppress macrophage function in a similar manner with inhibition of proton pump through binding to SH-molecules. When macrophages were preincubated with AG2000 for 1 hr and washed, their anti-Candida activity remained to be partially inhibited for 14 hrs. These results were discussed in relation to the pathogenesis of esophageal candidiasis.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2001

[In vitro assay method for augmention of anti-Candida activity of murine bone marrow cells by cytokines].

It is important to develop a sensitive assay method for evaluation of immunomodulating candidates including granulocyte-colony stimulating factor (G-CSF) which may augment host defense function against opportunistic infections. Effects of CSFs on anti-Candida activity of bone marrow cells (BMC) obtained from normal or cyclophosphamide-treated immunocompromised mice (CY-mice) were investigated. When BMC from CY-mice were preincubated for 24 hours in the presense of more than 0.005 ng/ml of G-CSF, anti-Candida activity was enhanced at 160 of effector (BMC) to target (C. albicans) ratio, whereas anti-Candida activity of BMC from CY-untreated mice was not changed at concentrations less than only by more than 0.5 ng/ml of G-CSF. Similar enhancement of activity was also observed in the presence of more than 0.05 ng/ml of granulocyte-macrophage colony stimulating factor (GM-CSF) in this assay using BMC from CY-mice. These findings suggest that this in vitro assay method can evaluate the activity of G-CSF and GM-CSF to augment leukocyte's anti-Candida activity.

Animals↗

PubMed2001

In vitro antifungal activity of KP-103, a novel triazole derivative, and its therapeutic efficacy against experimental plantar tinea pedis and cutaneous candidiasis in guinea pigs.

The in vitro activity of KP-103, a novel triazole derivative, against pathogenic fungi that cause dermatomycoses and its therapeutic efficacy against plantar tinea pedis and cutaneous candidiasis in guinea pigs were investigated. MICs were determined by a broth microdilution method with morpholinepropanesulfonic acid-buffered RPMI 1640 medium for Candida species and with Sabouraud dextrose broth for dermatophytes and by an agar dilution method with medium C for Malassezia furfur. KP-103 was the most active of all the drugs tested against Candida albicans (geometric mean [GM] MIC, 0.002 microg/ml), other Candida species including Candida parapsilosis and Candida glabrata (GM MICs, 0.0039 to 0.0442 microg/ml), and M. furfur (GM MIC, 0.025 microg/ml). KP-103 (1% solution) was highly effective as a treatment for guinea pigs with cutaneous candidiasis and achieved mycological eradication in 8 of the 10 infected animals, whereas none of the imidazoles tested (1% solutions) was effective in even reducing the levels of the infecting fungi. KP-103 was as active as clotrimazole and neticonazole but was less active than lanoconazole and butenafine against Trichophyton rubrum (MIC at which 80% of isolates are inhibited [MIC(80)], 0.125 microg/ml) and Trichophyton mentagrophytes (MIC(80), 0.25 microg/ml). However, KP-103 (1% solution) exerted therapeutic efficacy superior to that of neticonazole and comparable to those of lanoconazole and butenafine, yielding negative cultures for all samples from guinea pigs with plantar tinea pedis tested. This suggests that KP-103 has better pharmacokinetic properties in skin tissue than the reference drugs. Because the in vitro activity of KP-103, unlike those of the reference drugs, against T. mentagrophytes was not affected by hair as a keratinic substance, its excellent therapeutic efficacy seems to be attributable to good retention of its antifungal activity in skin tissue, in addition to its potency.

Animals↗

PubMed2001

Chlamydia pneumoniae infects and multiplies in lymphocytes in vitro.

The obligate intracellular pathogen Chlamydia (Chlamydophila) pneumoniae is known to be associated with some chronic inflammatory diseases, such as atherosclerosis. Interaction between C. pneumoniae and immune cells is important in the development of such diseases. However, susceptibility of immune cells, particularly lymphocytes, to C. pneumoniae infection has not been reported, even though lymphocytes play a pivotal role in the development of the diseases caused by this bacterium. In this regard, we examined the susceptibility of lymphocytes to C. pneumoniae infection in vitro. The results demonstrated that human peripheral blood lymphocytes as well as mouse spleen lymphocytes could be infected with C. pneumoniae. Furthermore, purified T lymphocytes as well as established T-lymphocyte cell line cells showed an obvious susceptibility to C. pneumoniae infection, indicating that T cells could be one of the host cells for this bacterial infection. These findings reveal a new infection site for C. pneumoniae, i.e., lymphocytes.

Animals↗

PubMed2001

Comprehensive DNA microarray analysis of Bacillus subtilis two-component regulatory systems.

It has recently been shown through DNA microarray analysis of Bacillus subtilis two-component regulatory systems (DegS-DegU, ComP-ComA, and PhoR-PhoP) that overproduction of a response regulator of the two-component systems in the background of a deficiency of its cognate sensor kinase affects the regulation of genes, including its target ones. The genome-wide effect on gene expression caused by the overproduction was revealed by DNA microarray analysis. In the present work, we newly analyzed 24 two-component systems by means of this strategy, leaving out 8 systems to which it was unlikely to be applicable. This analysis revealed various target gene candidates for these two-component systems. It is especially notable that interesting interactions appeared to take place between several two-component systems. Moreover, the probable functions of some unknown two-component systems were deduced from the list of their target gene candidates. This work is heuristic but provides valuable information for further study toward a comprehensive understanding of the B. subtilis two-component regulatory systems. The DNA microarray data obtained in this work are available at the KEGG Expression Database website (http://www.genome.ad.jp/kegg/expression).

Bacillus subtilis↗

PubMed2001

Endoscopic mucosal resection for treatment of early gastric cancer.

BACKGROUND: In Japan, endoscopic mucosal resection (EMR) is accepted as a treatment option for cases of early gastric cancer (EGC) where the probability of lymph node metastasis is low. The results of EMR for EGC at the National Cancer Center Hospital, Tokyo, over a 11 year period are presented. METHODS: EMR was applied to patients with early cancers up to 30 mm in diameter that were of a well or moderately histologically differentiated type, and were superficially elevated and/or depressed (types I, IIa, and IIc) but without ulceration or definite signs of submucosal invasion. The resected specimens were carefully examined by serial sections at 2 mm intervals, and if histopathology revealed submucosal invasion and/or vessel involvement or if the resection margin was not clear, surgery was recommended. RESULTS: Four hundred and seventy nine cancers in 445 patients were treated by EMR from 1987 to 1998 but submucosal invasion was found on subsequent pathological examination in 74 tumours. Sixty nine percent of intramucosal cancers (278/405) were resected with a clear margin. Of 127 cancers without "complete resection", 14 underwent an additional operation and nine were treated endoscopically; the remainder had intensive follow up. Local recurrence in the stomach occurred in 17 lesions followed conservatively, in one lesion treated endoscopically, and in five lesions with complete resection. All tumours were diagnosed by follow up endoscopy and subsequently treated by surgery. There were no gastric cancer related deaths during a median follow up period of 38 months (3-120 months). Bleeding and perforation (5%) were two major complications of EMR but there were no treatment related deaths. CONCLUSION: In our experience, EMR allows us to perform less invasive treatment without sacrificing the possibility of cure.

Adult↗

PubMed2001

Effects of cyclopiazonic acid on cytosolic calcium in bovine airway smooth muscle cells.

In many cells, inhibition of sarcoplasmic reticulum (SR) Ca2+-ATPase activity induces a steady-state increase in cytosolic calcium concentration ([Ca2+]i) that is sustained by calcium influx. The goal was to characterize the response to inhibition of SR Ca2+-ATPase activity in bovine airway smooth muscle cells. Cells were dispersed from bovine trachealis and loaded with fura 2-AM (0.5 microM) for imaging of single cells. Cyclopiazonic acid (CPA; 5 microM) inhibited refilling of both caffeine- and carbachol-sensitive calcium stores. In the presence of extracellular calcium, CPA caused a transient increase in [Ca2+]i from 166 +/- 11 to 671 +/- 100 nM, and then [Ca2+]i decreased to a sustained level (CPA plateau; 236 +/- 19 nM) significantly above basal. The CPA plateau spontaneously declined toward basal levels after 10 min and was attenuated by discharging intracellular calcium stores. When CPA was applied during sustained stimulation with caffeine or carbachol, decreases in [Ca2+]i were observed. We concluded that the CPA plateau depended on the presence of SR calcium and that SR Ca2+-ATPase activity contributed to sustained increases in [Ca2+]i during stimulation with caffeine and, to a lesser extent, carbachol.

Animals↗

PubMed2001

Enhancement of branching efficiency by the actin filament-binding activity of N-WASP/WAVE2.

The actin-related protein (Arp) 2/3 complex is an essential regulator of de novo actin filament formation. Arp2/3 nucleates the polymerization of actin and creates branched actin filaments when activated by Arp2/3-complex activating domain (VCA) of Wiskott-Aldrich syndrome proteins (WASP family proteins). We found that the branching of actin filaments on pre-existing ADP filaments mediated by the Arp2/3 complex is twice as efficient when Arp2/3 was activated by wild-type neural WASP (N-WASP) or WASP-family verprolin-homologous protein (WAVE) 2 than when activated by the VCA domain alone. By contrast, there was no difference between wild-type N-WASP or WAVE2 and VCA in the branching efficiency on de novo filaments, which are thought to consist mainly of ADP-phosphate filaments. This increased branching efficiency on ADP filaments is due to the basic region located in the center of N-WASP and WAVE2, which was found to associate with ADP actin filaments. Actin filaments and phosphatidylinositol bisphosphate (PIP2) associate with N-WASP at different sites. This association of N-WASP and WAVE2 with actin filaments enhanced recruitment of Arp2/3 to the pre-existing filaments, presumably leading to efficient nucleation and branch formation on pre-existing filaments. These data together suggest that the actin filament binding activity of N-WASP and WAVE2 in the basic region increases the number of barbed ends created on pre-existing filaments. Efficient branching on ADP filaments may be important for initiation of actin-based motility.

Actin Cytoskeleton↗