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Biomedical subjects

Y Asai

Publications and source records attributed to Y Asai.

At least 19 recordsLinked to original sources
PubMed2006

Natural killer cell activities of synbiotic Lactobacillus casei ssp. casei in conjunction with dextran.

We have reported previously that Lactobacillus casei ssp. casei, together with specific substrate dextran, exhibited an adjuvant effect of stimulating humoral immune responses against bovine serum albumin (BSA) as a model antigen in BALB/c mice. In the present study, among the Lactobacillus species tested, L. casei ssp. casei with dextran significantly elevated the natural killer (NK) cell activities in spleen mononuclear cells from BALB/c mice in comparison to L. casei ssp. casei alone or other Lactobacillus species with or without dextran. Oral administration of L. casei ssp. casei together with dextran also resulted in a significant increase of NK cell activities in healthy human volunteers. Further, L. casei ssp. casei induced significant production of interleukin (IL)-12 in human peripheral blood mononuclear cells and IL-15 mRNA expression in the human intestinal epithelial cell line Caco-2. L. casei ssp. casei with dextran in food also significantly elevated the survival rate of BALB/c mice bearing Meth-A cells. Taken together, these results demonstrate that dietary synbiotic supplementation which is a combination of the L. casei ssp. casei used as a probiotic together with the dextran, a specific substrate as a prebiotic, efficiently elicits murine and human NK cell activities.

Adult↗
PubMed2006

Correlation between chemical structure and biological activities of Porphyromonas gingivalis synthetic lipopeptide derivatives.

We recently separated a PG1828-encoded triacylated lipoprotein (Pg-LP), composed of two palmitoyl and one pentadecanoyl groups at the N-terminal of glycerocysteine from Porphyromonas gingivalis, a periodontopathic bacteria, and found that Pg-LP exhibited definite biological activities through Toll-like receptor (TLR) 2. In the present study, we synthesized 12 different Pg-LP N-terminal peptide moieties (PGTP) using four combinations of glyceryl (R and S) and cysteinyl (l and d) stereoisomers, and three different acyl group regioisomers, N-pentadecanoyl derivative (PGTP1), S-glycero 2-pentadecanoyl derivative (PGTP2) and S-glycero 3-pentadecanoyl derivative (PGTP3). All the PGTP compounds (RL, SL, SD, RD) tested showed TLR2-dependent cell activation. The activating capacities of the PGTP-R compounds were more potent than those of the PGTP-S compounds, whereas there were no differences between the PGTP-L and -D compounds. Furthermore, the production of interleukin (IL)-6 following stimulation with the PGTP1-RL, PGTP2-RL and PGTP3-RL compounds was impaired in peritoneal macrophages from TLR2 knock-out (KO), but not those from TLR1 KO or TLR6 KO mice. These results suggest that P. gingivalis triacylated lipopeptides are capable of activating host cells in a TLR2-dependent and TLR1-/TLR6-independent manner, and the fatty acid residue at the glycerol position in the PGTP molecule plays an important role in recognition by TLR2.

Adult↗
PubMed2005

Nominal free air in the left inguinal fossa due to perforation of the sigmoid colon in a case of blunt abdominal trauma: CT diagnosis.

We present a case of perforation of the sigmoid colon due to blunt abdominal trauma. Computed tomography showed nominal free air in the inguinal fossa. The distribution of free air may be a clue to the site of an injured intestine. Early detection of intestinal injury is difficult, but repeated computed tomography after several hours may reveal increased free air.

Abdominal Injuries↗
PubMed2005

Psychophysical analysis of monitor display functions affecting observer diagnostic performance of CT image on liquid crystal display monitors.

The aim of the present study was to propose suitable display functions for CT image representation on liquid crystal display (LCD) monitors by analyzing the characteristics of the monitor's typical display functions using psychophysical analysis. The luminance of the LCD monitor was adjusted to a maximum of 275 cd/m2 and 480 cd/m2. Three types of postcalibrated display functions (i.e., GSDF, CIELAB, and Exponential gamma 2.2) were evaluated. Luminance calculation of a new grayscale test pattern (NGTP) was done for the conversion of the digital driving level (DDL) into the CT value. The psychophysical gradient delta of display functions for the CT value was evaluated and compared via statistical analysis. The delta value of GSDF and CIE decreased exponentially; however, the delta value of Exponential gamma 2.2 showed a convex curve with a peak at a specific point. There was a statistically significant difference among the delta values of the three types of display functions on the 480 cd/m2 maximum via Kruskal Wallis test (P<0.001). The GSDF was suitable for observation of abdominal and lung CT images; however, the display function combined the Exponential gamma 2.2 and the GSDF functions and was ideal for observation of brain CT images by psychophysical analysis.

Brain↗
PubMed2005

Evaluation of grey-scale standard display function as a calibration tool for diagnostic liquid crystal display monitors using psychophysical analysis.

The digital imaging and communications in medicine (DICOM) standard proposed the grey-scale standard display function (GSDF) as a calibration tool for making the gradation characteristic of a radiographic output image consistent. This is designed in such a manner that the contrast visually recognised by observers (called psychophysical contrast) becomes a constant for all digital driving levels. The DICOM standard calls such an ideal characteristic perceptual linearisation. The psychophysical gradient that can express the psychophysical contrast was introduced for the evaluation of the GSDF using a liquid crystal display monitor. Investigations regarding its ability to yield a constant psychophysical contrast, independent of the digital driving level change and under an actual observation environment, such as for clinical radiographic diagnosis in hospital, were carried out. The psychophysical gradients of the GSDF were obtained for two kinds of observation environment: one was a restricted environment such as in a dark room, under steady-state adaptation, using the sinusoidal grading pattern corresponding to the peak frequency of the human eye response. The other was an actual environment reflecting that encountered during clinical diagnosis in a hospital. As a result, the psychophysical gradient under the restricted environment became almost constant and independent of the change in digital driving level, i.e. perceptual linearisation could be satisfied. Furthermore, under the actual observation environment, the psychophysical gradient decreased gradually with the increase in digital driving level, i.e. the perceptual linearisation could not be satisfied. The percentage decrease in the value of the psychophysical gradient at the maximum luminance area was approximately 60% compared with that at the minimum luminance area. Accordingly, the GSDF is unsuitable as a calibration tool for the liquid crystal display monitor, which will be used in actual clinical diagnosis, as it cannot achieve 'perceptual linearisation' under the actual environment. For the purpose of clinical diagnosis, it is necessary to enlarge the physical gradient of GSDF further in the high digital driving level range (which relates to a high luminance area) to give an approximation that is as close to the idealised form as possible.

Calibration↗
PubMed2005

Treponema medium glycoconjugate inhibits activation of human gingival fibroblasts stimulated with phenol-water extracts of periodontopathic bacteria.

Oral treponemes are well-known as causative agents of periodontal diseases; however, the details have not been fully clarified. Here, we examined the effects of Treponema medium glycoconjugate on the activation of human gingival fibroblasts using phenol-water extracts from Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum subsp. nucleatum, and Actinobacillus actinomycetemcomitans. The phenol-water extracts activated human gingival fibroblasts to mediate IL-8 production, as well as IL-8 mRNA expression, phosphorylation of p38 mitogen-activated protein kinase, and expression of intercellular adhesion molecule-1. T. medium glycoconjugate exhibited no activation of human gingival fibroblasts, while phenol-water extract-induced activation of human gingival fibroblasts was clearly inhibited by T. medium glycoconjugate. Furthermore, binding of biotinylated phenol-water extracts to CD14 in the presence of LPS-binding protein was blocked with T. medium glycoconjugate. These results suggest that T. medium glycoconjugate has an inhibitory effect on host cell activation by periodontopathic bacteria caused by binding to CD14- and LPS-binding protein.

Acute-Phase Proteins↗
PubMed2005

Formation of spherical micelles composed of the novel platelet activating factor receptor antagonist, E5880.

E5880, a novel platelet activating factor receptor antagonist, was dispersed in water for use in an injectable formulation and the physicochemical properties of the preparation were characterized. The critical concentration for formation of micelles was 0.12 mM. Using area per molecule data, the critical packing parameter was calculated, indicating that the structure of the micelles was spherical and that each micelle containes 49 molecules. The diameter of the micelles was 8.1 nm. Attractive interactions occurred between E5880 molecules in the micelle. The hydrocarbon region in the micelle was more rigid and less hydrated than that of other surfactants, stearyltrimethylammonium chloride and cetyltrimethylammonium chloride.

Algorithms↗
PubMed2004

Development and evaluation of a new gray-scale test pattern to adjust gradients of thoracic CT imaging.

The purpose of the present study was to evaluate the usefulness of a new gray-scale test pattern (NGTP) that was developed to easily adjust the gradients of thoracic CT imaging and enable visual consistency. The Society of Motion Picture and Television Engineers (SMPTE) pattern and the NGTP were used for comparison. The luminance character of two test patterns was evaluated by a luminance meter with three different window widths and levels (for default, mediastinum and lung). We also investigated whether SMPTE or NGTP is more suitable for adjusting the gradient of thoracic CT imaging. We found that it was easier to adjust the gradient of thoracic CT imaging with NGTP than with SMPTE, because the digital range of NGTP is 12 bits (the value of 4,096 HU, from -1,024 to 3,071 HU), and adjustable in any window width. We were able to adjust the gradients of hard-copy and soft-copy thoracic CT imaging within several hours using NGTP. We propose that NGTP is the most suitable tool for adjusting the gradients of thoracic CT imaging. NGTP can cope with any medical diagnostic display system connected with CT or MRI equipment in a network because it is in DICOM format.

Quality Control↗
PubMed2004

Correlations of hemoglobin index (IHb) of gastric mucosa with Helicobacter pylori (H. pylori) infection and inflammation of gastric mucosa.

BACKGROUND: Helicobacter pylori (H. pylori) infection causes various gastric diseases, among them H. pylori-associated gastritis characterized by diffuse redness of the gastric mucosa. The haemoglobin index (IHb) of the fundic mucosa is an objective parameter of the extent of mucosal redness, but it is unclear whether or not IHb can be used as a diagnostic marker for H. pylori infection. The purpose of this investigation was to evaluate the correlations between IHb of the fundic mucosa and H. pylori infection, inflammatory cell infiltration, and inflammatory mediator production. METHODS: IHb of the fundic mucosa was measured in 108 patients with various gastric diseases (group 1), and values were compared between H. pylori-positive and H. pylori-negative patients. Fifteen patients with H. pylori infection from group 1 underwent H. pylori eradication therapy and IHb was measured before and after treatment. Both IHb and inflammatory cell infiltration were assessed in 61 patients (group 2). In 31 patients from group 2, the expression of interleukin (IL)-8 and inducible nitric oxide synthase (iNOS) messenger RNA (mRNA) was assayed in gastric biopsy specimens by the reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: IHb levels were significantly higher in H. pylori-positive patients than in H. pylori-negative patients (P < 0.001). IHb was decreased at one month after the eradication of H. pylori (P < 0.001). IHb was higher in patients with infiltration by both mononuclear cells and neutrophils (P < 0.001). There was a significant correlation between the IHb level and the expression of IL-8 mRNA (P < 0.001), as well as between IHb and iNOS mRNA expression (P < 0.05). CONCLUSIONS: There were significant correlations between IHb of the gastric mucosa and H. pylori infection, inflammatory cell infiltration, and IL-8/iNOS mRNA expression, suggesting that IHb is a reliable marker of H. pylori infection for use during follow-up endoscopy after H. pylori eradication therapy.

Biomarkers↗
PubMed2004

Reductions in levels of bacterial superantigens/cannabinoids by plasma exchange in a patient with severe toxic shock syndrome.

Toxic shock syndrome is a rare but potentially fatal toxin-mediated febrile illness. We report a case of toxic shock syndrome complicated by life-threatening organ dysfunction with high toxin-1 and staphylococcus enterotoxin type A levels that were successfully reduced by early introduction of plasma exchanges. The report shows the time course of the concentrations of anandamide and 2-arachidonyl glyceride and confirms that early introduction of plasma exchange can result in a rapid reduction of circulating toxins and mediators in the treatment of life-threatening multiple organ dysfunction.

Adolescent↗
PubMed2004

Structural differences in aqueous dispersions of alpha-tocopheryl acetate and phosphatidylcholine upon varying their molar fractions.

The purpose of this study was to investigate the structure of dispersed particles composed of alpha-tocopheryl acetate (TA) and phospholipid. TA was dispersed with soybean phosphatidylcholine (PC) using sonication and the dispersal mechanism was evaluated by characterizing the dispersed particles using dynamic light scattering, fluorescence spectroscopy and surface layer techniques. The dispersions in the TA mole fraction range of 0.1-0.7 were stable at room temperature for 3 days. A limited amount of TA was incorporated into PC bilayer membranes (approximately 5 mol%). The excess TA separated from the PC bilayers was stabilized as emulsion particles by the PC surface monolayer. When the PC content was less than the solubility in TA (mole fraction of TA: more than 0.8), the PC monolayer did not completely cover the hydrophobic TA particle surfaces. In the case, the particle size increased drastically andseparation into oil and water occurred. The miscibility between TA and PC and the lipid composition were critically important for the stability of the dispersed particles (coexistence of emulsion particles [surface monolayer of PC + core of TA] with vesicular particles [bilayer]) of the lipid mixtures.

Chemical Phenomena↗
PubMed2003

Emergency endovascular stent-grafting for infected pseudoaneurysm of brachial artery.

The use of covered stents in an infected field is controversial. It is generally recommended that infected aneurysms be treated using autografts or allografts. We report a case of infected brachial pseudoaneurysms that developed after medical debridement of a methicillin-resistant Staphylococcus aureus (MRSA)-infected wound of the right arm and emergency brachial artery bypass-grafting using the saphenous vein, which was successfully treated by endovascular stent-grafting followed by antibiotic administration. The present case suggests that endovascular stent-grafting prevents rupture and occlusion of infected aneurysms and enables the continued administration of antibiotics.

Adult↗
PubMed2003

Amended biochemical characteristics and phylogenetic position of Treponema medium.

Umemoto et al. (1997, Int J Syst Bacteriol 47, pp. 67-72) proposed spirochete strain G7201, isolated from the periodontal pocket of an adult patient, as a new species, Treponema medium. They deposited this strain in the American Type Culture Collection (ATCC) as type strain ATCC 700293T. Recently, ATCC suggested that there is a discrepancy between the previous report and the results obtained by ATCC in biochemical tests on T. medium ATCC 700293T. In this study, we re-examined and verified the biochemical characteristics of T. medium. The fermentation pattern of carbohydrates of T. medium resembled that of Treponema vincentii and Treponema denticola, but T. medium was clearly differentiated from T. vincentii in the production of indole, and from T. denticola in the hydrolysis of esculin. Also, sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) protein profile analysis and phylogenetic comparison of 16S rDNA sequences revealed that T. medium is clearly differentiated from any established treponemal species, which supports the validity of the proposal of Treponema medium as a new species.

Bacterial Proteins↗
PubMed2003

A novel p63 sterile alpha motif (SAM) domain mutation in a Japanese patient with ankyloblepharon, ectodermal defects and cleft lip and palate (AEC) syndrome without ankyloblepharon.

We present a sporadic case of a Japanese female infant with ectodermal dysplasia, complete cleft lip and palate, severe skin erosions at birth and recurrent scalp infection. She had typical clinical features of ankyloblepharon, ectodermal defects and cleft lip and palate (AEC) syndrome without ankyloblepharon. Histological and immunohistochemical analyses showed reduced granular cell layers and aberrant expression of the p63 protein in the suprabasal keratinocytes. Mutation analysis of the exon 13 of p63 gene revealed a heterozygous in-frame 3-bp insert (c. 538-539 ins TTC) encoding additional amino acid residues (F). This is the first report of sterile alpha motif domain mutation except for single nucleotide transitions.

Abnormalities, Multiple↗
PubMed2003

Severe paradoxical intracranial embolism and pulmonary emboli during hip hemiarthroplasty.

Both paradoxical intracranial embolism, an intracranial arterial embolism caused by venous embolic material that has passed through a right-to-left shunt, and pulmonary arterial embolism are life-threatening complications of joint arthroplasty. We report a case of severe paradoxical intracranial embolism and pulmonary embolism that occurred during hip hemiarthroplasty.

Aged↗
PubMed2003

Detectable dioxins in human saliva and their effects on gingival epithelial cells.

Dioxin, a powerful hormone-disrupting chemical, exhibits serious health effects when it reaches body fat. Here we analyzed coplanar polychlorinated biphenyls (PCBs) and polychlorinated-dibenzo-p-dioxins (PCDDs) in human saliva as compared with blood specimens, and examined their effects on human gingival epithelial cells (HGEC). High levels of tri- and tetrachlorinated PCBs were found in saliva, whereas we detected predominantly hexa- and heptachlorinated PCBs in blood. Among PCDDs, the saliva and blood specimens contained mainly 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD). Among the toxic dioxins proposed by the World Health Organization (WHO) in 1998, 2,3',4,4',5-pentachlorobiphenyl (PCB 118) and OCDD, which were mainly found in saliva, significantly induced IL-8 production in HGEC. Furthermore, these two dioxins markedly augmented IL-8 production stimulated with fimbriae from Porphyromonas gingivalis, which is well-known as a pathogenic factor in periodontal diseases. These results suggest that dioxins in saliva may be a risk factor for periodontal diseases.

Analysis of Variance↗