Search PubMed⌕ Search

Biomedical subjects

I Okayasu

Publications and source records attributed to I Okayasu.

At least 19 recordsLinked to original sources
PubMed2006

Effect of reclining and chin-tuck position on the coordination between respiration and swallowing.

Chin-tuck position and reclining posture have been used in dysphagia patients to prevent aspiration during swallowing. However, both behavioural treatments may affect respiratory function. This study was carried out to test the hypothesis that if chin-tuck posture and body reclining affected respiratory function, this would be associated with altered coordination between respiration and swallowing. To investigate this hypothesis, respiratory parameters and manometry were used in each of four combinations of reclining posture and chin-tuck position. In the 60 degrees reclining with 60 degrees chin-tuck position, duration of swallowing apnea (0.89 s.d. 0.17 s) and submental electromyography burst (2.34 s.d. 0.84 s) were significantly longer when compared to both upright sitting and 30 degrees reclining positions. We conclude that 60 degrees reclining from vertical with 60 degrees chin-tuck may affect oral processing stages which delay and reduce a variety of oropharyngeal movements. These in turn significantly influence the coordination between respiration and swallowing.

Adult↗
PubMed2005

Mucosa-associated bacteria in ulcerative colitis before and after antibiotic combination therapy.

BACKGROUND: We proposed that Fusobacterium varium is one of the causative agents in ulcerative colitis. AIM: To examine the efficacy of antibiotic combination therapy against F. varium and to investigate the mucosa-associated bacteria before and after the therapy using a new molecular approach. METHODS: Twenty patients with ulcerative colitis were randomly assigned into the antibiotic treatment group (amoxicillin, tetracycline and metronidazole for 2 weeks) and no-antibiotics group. Clinical assessment, colonoscopic and histological evaluations were performed at 0 and 3-5 months after the treatment. DNA from mucosal bacteria was isolated from biopsy specimens. We investigated the mucosa-associated bacterial components by terminal restriction fragment length polymorphism with the restriction enzyme HhaI and MspI, and quantified the change in the number of bacteria by real-time polymerase chain reaction. Immunohistochemical detection of F. varium in biopsy specimens was also performed. RESULTS: After the treatment, the clinical assessment, colonoscopic and histological scores improved in the antibiotic group compared with the control group. Three peaks of terminal restriction fragment length polymorphism decreased after treatment only in the antibiotic group. Eubacterium rectale, Dorea formicigenerans, Clostridium clostridioforme and F. varium were included in these peaks. Based on the real-time polymerase chain reaction study, only F. varium was significantly reduced after treatment. In the immunostaining, post-treatment scores in treatment group were significantly lower than that in control group. CONCLUSIONS: Antibiotics combination therapy was effective for ulcerative colitis. The number of mucosa-associated F. varium significantly decreased after the treatment.

Amoxicillin↗
PubMed2005

Effect of mandibular position on upper airway collapsibility and resistance.

It has been proposed that advancement of the mandible is a useful method for decreasing upper airway collapsibility. We carried out this study to test the hypothesis that mandibular advancement induces changes in upper airway patency during midazolam sedation. To explore its effect, we examined upper airway pressure-flow relationships in each of 4 conditions of mouth position in normal, healthy subjects (n = 9). In the neutral position, Pcrit (i.e., critical closing pressure, an index of upper airway collapsibility) was -4.2 cm H(2)O, and upstream resistance (Rua) was 21.2 cm H(2)O/L/sec. In the centric occlusal position, Pcrit was -7.1 cm H(2)O, and Rua was 16.6 cm H(2)O/L/sec. In the incisor position, Pcrit was significantly reduced to -10.7 cm H(2)O, and Rua was significantly reduced to 14.0 cm H(2)O/L/sec. Mandibular advancement significantly decreased Pcrit to -13.3 cm H(2)O, but did not significantly influence Rua (22.1 cm H(2)O/L/sec). We conclude that the mandibular incisors' position improved airway patency and decreased resistance during midazolam sedation.

Adult↗
PubMed2004

Upregulation of p16(INK4A) and Bax in p53 wild/p53-overexpressing crypts in ulcerative colitis-associated tumours.

In ulcerative colitis (UC)-associated tumours, p53 gene mutations and p53 protein overexpression are frequently found in early stages, but the two types of alteration do not always coincide. To clarify this discrepancy, p53 mutations and expression of p53-associated molecules were analysed in UC-associated dysplasias by a combination of microdissection, polymerase chain reaction-direct sequencing and immunohistochemistry at the single crypt level. Mismatch of p53 protein overexpression (+)/mutation (-) or p53 overexpression (-)/gene mutation (+) was found in nine crypts in regenerative mucosa (19 crypts), in 27 in low-grade dysplasia (41), in one in high-grade dysplasia (5) and in 12 in invasive carcinomas (17). Regarding these mismatched crypts of the first type, significant increase in p16(INK4A) and Bax expression was found. The Ki-67 labelling index was depressed in such p53-diffusely positive lesions with the wild-type p53 gene, compared to their p53-diffusely positive and mutant type counterparts. p16(INK4A) was upregulated indirectly as part of the negative feedback, and increase in Bax, directly controlled by wild-type p53, indicates upregulation of apoptosis. No significant relation with p53-related gene products was detected with the p53 protein overexpression (-)/p53 mutation (+) mismatch. Therefore, a tumorigenesis pathway independent of p53 dysfunction appears to exist in association with ulcerative colitis.

Adult↗
PubMed2004

High microvascular density is correlated with high VEGF, iNOS and COX-2 expression in penetrating growth-type early gastric carcinomas.

AIMS: Early gastric carcinomas have two characteristic growth types, superficial spreading (SUP) and penetrating (PEN). Higher mucosal apoptotic activity and lower p21(WAF1/CIP1) expression and submucosal low proliferative activity have been shown in the former, compared with the latter. In order to cast light on whether angiogenesis contributes to these growth patterns, the present immunohistochemical study was performed with cancer tissues. METHODS AND RESULTS: Of a total of 807 early gastric carcinomas, 30 PEN and 33 SUP type submucosal invasive carcinoma cases were immunohistochemically compared. CD34 positivity, microvascular density (MVD), and expression of vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS), but not cyclooxygenase 2 (COX-2) were higher in cancer cells in both mucosal and submucosal layers in PEN than in SUP (P < 0.05). Submucosal MVD in PEN type was greater (P < 0.01) in cases with high than with low Ki67 labelling. Significant correlations were shown between MVD and VEGF, iNOS and COX-2, and VEGF and iNOS expression in the PEN type, but only a weak correlation between iNOS and COX-2 expression was evident with the SUP type. CONCLUSIONS: Increased MVD in PEN type has an intimate causal relationship to angiogenic factors, high VEGF and iNOS expression. The SUP type, in contrast, has characteristics of low angiogenesis.

Angiogenic Proteins↗
PubMed2004

Mouth-opening increases upper-airway collapsibility without changing resistance during midazolam sedation.

Sedative doses of anesthetic agents affect upper-airway function. Oral-maxillofacial surgery is frequently performed on sedated patients whose mouths must be as open as possible if the procedures are to be accomplished successfully. We examined upper-airway pressure-flow relationships in closed mouths, mouths opened moderately, and mouths opened maximally to test the hypothesis that mouth-opening compromises upper-airway patency during midazolam sedation. From these relationships, upper-airway critical pressure (Pcrit) and upstream resistance (Rua) were derived. Maximal mouth-opening increased Pcrit to -3.6 +/- 2.9 cm H2O compared with -8.7 +/- 2.8 (p = 0.002) for closed mouths and -7.2 +/- 4.1 (p = 0.038) for mouths opened moderately. In contrast, Rua was similar in all three conditions (18.4 +/- 6.6 vs. 17.7 +/- 7.6 vs. 21.5 +/- 11.6 cm H2O/L/sec). Moreover, maximum mouth-opening produced an inspiratory airflow limitation at atmosphere that was eliminated when nasal pressure was adjusted to 4.3 +/- 2.7 cm H2O. We conclude that maximal mouth-opening increases upper-airway collapsibility, which contributes to upper-airway obstruction at atmosphere during midazolam sedation.

Adult↗
PubMed2003

Possible alternative carcinogenesis pathway featuring microsatellite instability in colorectal cancer stroma.

Differential microsatellite instability (MSI) in tumour epithelial and stromal compartments has not been well examined for colorectal cancers. Using laser-captured microdissection, separate specimens of these compartments of 40 sporadic colorectal cancers were sampled and MSI was tested with four markers. To examine the relation between the MSI phenotype in the stroma and other genetic events and histopathological features, p53 and K-ras gene mutations were analysed, and the expression of p53, hMLH1, and hMSH2 protein was determined by immunohistochemistry. Microsatellite instability positive results were obtained for both epithelium (34%) and stromal tissue (41%). While MSI in epithelium correlated with differentiation and Dukes' stage, that in stroma demonstrated an inverse relation, being particularly frequent in well-differentiated adenocarcinomas (54%) and Dukes' A lesions (55%). Further, a significant inverse correlation between p53 protein overexpression in the epithelium and MSI in the stroma was found (P=0.02475). The results suggest an alternative pathway of carcinogenesis involving stromal genetic instability in the development of colorectal cancers.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Induction of experimental ulcerative colitis by Fusobacterium varium isolated from colonic mucosa of patients with ulcerative colitis.

BACKGROUND: Bacteria are implicated in certain forms of model chronic colitis but the identity and role of bacteria in human ulcerative colitis (UC) are uncertain. AIMS: To isolate pathogenic bacteria from inflamed mucosa of patients with UC, to examine whether the bacteria have a toxin to Vero cells, and to determine whether the toxin induces UC-like lesions in animals. METHODS: Bacteria were isolated from UC patients and supernatants from cultures were filtered and tested for cytotoxicity to Vero cells. Bacterial cells producing the cytotoxic supernatants were examined by polymerase chain reaction for verotoxin genes. Culture supernatants of cytotoxic strains were examined by high performance liquid chromatography for organic acid concentrations. Mice were given enemas containing organic acid at the mean concentration in the supernatants of cytotoxic strains to ascertain whether colonic lesions appear in UC. RESULTS: Only supernatants from cultures of Fusobacterium varium killed Vero cells. Bacterial cells lacked verotoxin genes. Bacterial culture supernatants contained high concentrations of n-butyric acid and the mean concentration (32 mmol/l) was cytotoxic to Vero cells. Twenty four hours after mice were given enemas containing either butyric acid or F varium culture supernatants, colonic ulcers with crypt abscesses, inflammatory cell infiltration, and apoptotic changes were observed. CONCLUSIONS: Butyric acid in culture supernatants from cultures of F varium caused UC-like lesions in mice. This study indicates that F varium may be one of the elusive pathogenic factors in UC.

Adult↗
PubMed2003

Helicobacter pylori infection induces duodenitis and superficial duodenal ulcer in Mongolian gerbils.

BACKGROUND: There is no direct evidence for an animal model of Helicobacter pylori induced duodenal ulcer. AIM: In this study we evaluated the roles of bacterial strain and age of experimental animals in induction of duodenitis and duodenal ulcer in Mongolian gerbils after H pylori infection. METHODS: Specific pathogen free Mongolian gerbils were inoculated orally with three bacterial strains (H pylori ATCC 43504, TN2GF4, and K-6, a clinical isolate from a patient with gastric cancer in our clinic). These strains have both the cagA gene and VacA. Five week old gerbils were used to emulate prematurity infection and 14 week old animals were used as mature test subjects. Animals were observed for 12 weeks after inoculation. Interleukin 8 (IL-8) production in gastric epithelial cells (MKN74) after coculture with the H pylori strains was measured by ELISA. RESULTS: Gastritis and gastric ulcers were found in all gerbils infected with the three strains. However, duodenitis and gastric metaplasia were seen more frequently in gerbils infected with TN2GF4 and K-6 strains than in the ATCC 43504 infected or control groups (p<0.05). Superficial duodenal ulcers with severe duodenitis and gastric metaplasia were found in two gerbils inoculated at 14 weeks with the TN2GF4 strain but none at five weeks. The TN2GF4 strain stimulated significantly higher levels of IL-8 than ATCC 43504 and K6 strains (p=0.0039). CONCLUSIONS: When injected into adult Mongolian gerbils, a specific strain (TN2GF4) of H pylori can induce duodenitis with gastric metaplasia and superficial duodenal ulcers. Induction of duodenal ulcer in an animal model fulfills the requirements of Koch's postulates for establishing a role for H pylori as a causative agent.

Age Factors↗
PubMed2003

New animal model for studying mastication in oral motor disorders.

To identify the basic parameters of oral behavior in mice, we recorded the three-dimensional jaw movement trajectories and masseter and digastric muscle activities in freely behaving mice eating foods of various textures. Results showed that: (1) there are characteristic jaw movement patterns for food intake and mastication; (2) the pattern in a chewing cycle may be divided into opening, closing, and protruding (power) strokes; and (3) food texture affects basic patterns of jaw movement, muscle activities, and chewing rhythms. The oral motor behavior of mice appears identical to those of other experimental animals, so mice are appropriate animal models for the study of mastication.

Animals↗
PubMed2002

Age-dependent differences in tumor cell polarity in endometrial carcinomas.

PURPOSE: Cell polarization is dependent on the structural asymmetry of apical and basolateral domains. Although clinical and biological heterogeneity of endometrial carcinomas in aged individuals has been proposed, little is known about the age-dependent differences in tumor morphology in terms of cell polarity. To clarify a possible significance of tumor cell polarity, a total of 92 cases of grade (G) 1 and G2 endometrial carcinomas (endometrioid type) were investigated. METHODS: Cell polarity for tumor glandular components was evaluated by examining the degree of three morphological parameters: nuclear ordering, basal positioning of nuclei within cells, and papillary snouting/glandular convolution. The results were also compared with findings for cell proliferation, expression of p21(Cip1)(p21), p27(Kip1)(p27), estrogen and progesterone receptors, p53 accumulation, and several clinicopathological factors. RESULTS: Average values for each polarity parameter showed a stepwise decrease from tumors of pre-, through peri-, to post-menopausal patients, the difference being significant. Significantly high values for all polarity scores were also evident in tumors adjacent to secretory non-neoplastic endometrium as compared to those in non-secretory tissue. Positive correlations with low cell proliferation determined with respect to Ki-67 labeling indices, early clinical stage, and upper myometrial invasion were also noted, while there were no associations with expression of p21, p27, p53, and two hormone receptors. CONCLUSIONS: These findings indicate that in endometrial carcinomas, the age-dependent differences in tumor cell polarity may be related to status of endogenous ovarian hormones, closely linked with cell proliferation and some prognostic factors.

Adult↗
PubMed2001

Human L-type amino acid transporter 1 (LAT1): characterization of function and expression in tumor cell lines.

System L is a major nutrient transport system responsible for the transport of large neutral amino acids including several essential amino acids. We previously identified a transporter (L-type amino acid transporter 1: LAT1) subserving system L in C6 rat glioma cells and demonstrated that LAT1 requires 4F2 heavy chain (4F2hc) for its functional expression. Since its oncofetal expression was suggested in the rat liver, it has been proposed that LAT1 plays a critical role in cell growth and proliferation. In the present study, we have examined the function of human LAT1 (hLAT1) and its expression in human tissues and tumor cell lines. When expressed in Xenopus oocytes with human 4F2hc (h4F2hc), hLAT1 transports large neutral amino acids with high affinity (K(m)= approximately 15- approximately 50 microM) and L-glutamine and L-asparagine with low affinity (K(m)= approximately 1.5- approximately 2 mM). hLAT1 also transports D-amino acids such as D-leucine and D-phenylalanine. In addition, we show that hLAT1 accepts an amino acid-related anti-cancer agent melphalan. When loaded intracellularly, L-leucine and L-glutamine but not L-alanine are effluxed by extracellular substrates, confirming that hLAT1 mediates an amino acid exchange. hLAT1 mRNA is highly expressed in the human fetal liver, bone marrow, placenta, testis and brain. We have found that, while all the tumor cell lines examined express hLAT1 messages, the expression of h4F2hc is varied particularly in leukemia cell lines. In Western blot analysis, hLAT1 and h4F2hc have been confirmed to be linked to each other via a disulfide bond in T24 human bladder carcinoma cells. Finally, in in vitro translation, we show that hLAT1 is not a glycosylated protein even though an N-glycosylation site has been predicted in its extracellular loop, consistent with the property of the classical 4F2 light chain. The properties of the hLAT1/h4F2hc complex would support the roles of this transporter in providing cells with essential amino acids for cell growth and cellular responses, and in distributing amino acid-related compounds.

Amino Acid Transport Systems↗
PubMed2001

Possible associations among expression of p14(ARF), p16(INK4a), p21(WAF1/CIP1), p27(KIP1), and p53 accumulation and the balance of apoptosis and cell proliferation in ovarian carcinomas.

BACKGROUND: Although there are several reports of changes in expression of cyclin-dependent kinase inhibitors in ovarian carcinomas, little is known about their associations with tissue kinetics in the various histologic subtypes. METHODS: In total, 131 carcinomas were immunohistochemically investigated for expression of p14(ARF) (p14), p16(INK4a) (p16), p21(WAF1/Cip1) (p21), and p27(Kip1) (p27). The results also were compared with data for apoptosis, cell proliferation, p53 status, and survival. Western blot and mRNA analyses were conducted on 35 malignant ovarian tumor samples. RESULTS: Significant differences in tissue kinetics determined by ratios of apoptotic relative to mitotic indices were observed among histologic subtypes of ovarian carcinomas, showing a shift toward predominance of cell proliferation in serous and cell deletion in clear cell types. The expression of p16, p21, p27, and p53 was associated closely with changes in cell proliferation rather than apoptosis and survival, dependent on the subtype. Positivity for p16 and p21 in the Western blot assay was significantly related to the results for immunohistochemical but not mRNA analyses, indicating possible posttranscriptional regulation of these genes. CONCLUSIONS: The findings indicate that the several cyclin-dependent kinase inhibitors investigated are expressed differently among histologic subtypes of ovarian carcinomas, associated with differences in tissue kinetics and the balance of apoptosis and cell proliferation.

Adult↗
PubMed2001

CD44 variant overexpression in gallbladder carcinoma associated with tumor dedifferentiation.

BACKGROUND: Recent studies have suggested a correlation between increased or decreased expression of CD44 variant molecules and tumor metastasis. CD44 expression in gallbladder carcinoma was examined and compared with tumor differentiation. METHODS: Eighty-three samples of gallbladder carcinoma, 17 gallbladder adenoma samples, and 66 normal control mucosa samples were stained immunohistochemically for CD44 standard form (CD44s), variant 3 (CD44v3), and variant 6 (CD44v6). RNA extracted from nine patients with carcinoma also was investigated with reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and Southern blot hybridization (SBH) for the CD44 gene. RESULTS: Normal gallbladder mucosa showed strong, membranous staining for CD44s but not for CD44v3 or CD44v6. In gallbladder tumors, CD44s was stained as strongly as it was in normal mucosa, but immunoreactivity for CD44v3 and CD44v6 also was significant. In well differentiated, advanced adenocarcinomas (n = 38), CD44s immunoreactivity was significantly lower in the invasive component than in the intramucosal component of the tumors (P = 0.0048). Immunoreactivity for CD44v3 and CD44v6 in moderately and poorly differentiated areas was significantly higher than in well differentiated areas (P < 0.0001 and P = 0.0378, respectively). RT-PCR and SBH signals for CD44v3 and CD44v6, including exons 7 and 10, were strong in carcinoma samples but weak in normal samples, in line with the results of immunohistochemistry. The prognosis of patients with gallbladder carcinoma was not associated significantly with altered expression of CD44s, CD44v3, or CD44v6. CONCLUSIONS: The current study demonstrated that CD44 variant overexpression in patients with gallbladder carcinoma was linked closely with histologic dedifferentiation rather than clinicopathologic factors, including prognosis.

Adenocarcinoma↗
PubMed2001

More frequent beta-catenin exon 3 mutations in gallbladder adenomas than in carcinomas indicate different lineages.

To clarify the contribution of beta-catenin, which is related to cell adhesion and intranuclear transcription, to gallbladder carcinogenesis, we investigated its expression using immunohistochemistry, and beta-catenin exon 3 mutations by DNA direct sequencing, in 18 gallbladder adenomas and 82 adenocarcinomas. Membranous expression was significantly lower in moderately and poorly differentiated than in well-differentiated adenocarcinoma cases (P < 0.001). The gallbladder adenomas showed significantly stronger expression in the cytoplasm and the nucleus than carcinomas (P < 0.05 and P < 0.001, respectively), and exon 3 mutations were observed in 62.5% (10 of 16) of adenomas, but only 4.8% (1 of 21) of carcinomas. With beta-catenin as a molecular marker, the adenoma-carcinoma sequence can be considered to be a minor pathway in gallbladder carcinogenesis.

Adenoma↗
PubMed2001

Frequent nuclear beta-catenin accumulation and associated mutations in endometrioid-type endometrial and ovarian carcinomas with squamous differentiation.

Focal squamous differentiation is a common feature of endometrioid endometrial and ovarian carcinomas (E-Em and E-Ova Cas). A close association between mutated beta-catenin accumulation and alteration in cellular morphology has recently been demonstrated in murine L cell lines. To clarify the possible role of beta-catenin abnormalities and changes in tumour morphology, 60 grade (G) 1 or G2 E-Em Cas with areas of squamous differentiation (SqD), including morules and squamous metaplastic (SqM) foci, as well as 32 G1 or G2 tumours without such lesions, were investigated and the results compared with findings for c-jun and wnt-1 expression. Twenty-three E-Ova Cas, with and without SqD lesions, were also examined. In E-Em Cas, frequent nuclear beta-catenin accumulation was observed in 22 (84.6%) of 26 tumours with morules and 15 (45.5%) of 33 with SqM foci, in contrast to 4 (12.5%) of 32 without such lesions. Similar findings were also noted for mutations in exon 3 of the beta-catenin gene, involving codons 32, 33, 34, 37, 41, and 45, the single nucleotide substitutions being identical between SqD and the surrounding carcinoma tissue in most informative cases. The mutations were positively related to nuclear immunopositivity, but inversely to membrane expression, while there was no association with the status of c-jun or wnt-1. These E-Ova Cas, nuclear beta-catenin accumulation and mutations were limited to tumours with SqD features, independent of c-jun and wnt-1 status. These data indicate that beta-catenin abnormalities are relatively common in E-Em and E-Ova Cas with SqD features, implying a role in the squamous differentiation of tumour cells, not necessarily related to c-jun and/or wnt-1 status.

Adenocarcinoma↗
PubMed2001

A new strategy for evaluation of the eradication treatment of Helicobacter pylori: validation of the analysis of mucin composition in human gastric juice.

The change in the mucin composition of human gastric juice has been investigated in patients before and after the eradication of the Helicobacter pylori (H. pylori) infection. We confirmed the successful eradication of H. pylori in all 17 patients. The gastric luminal mucins were divided into three fractions by ion-exchange chromatography using a discontinuous salt gradient with three salt steps. Although there was a significant variation in the proportion of the mucin content in each fraction among the individual patients, a decrease in the acidic mucin content after the eradication of H. pylori was commonly observed in all the patients. These results indicate that the mucin compositional analysis in the gastric luminal mucin may be a very useful tool for the assessment of H. pylori eradication.

Chromatography, Ion Exchange↗