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Biomedical subjects

Y Shimizu

Publications and source records attributed to Y Shimizu.

At least 55 records · Page 3Linked to original sources
PubMed2004

Comparison of various submucosal injection solutions for maintaining mucosal elevation during endoscopic mucosal resection.

BACKGROUND AND STUDY AIMS: One of the major complications of endoscopic mucosal resection (EMR) for gastrointestinal tumors is perforation, and the most effective way of preventing perforation is to elevate the lesion sufficiently by endoscopic injection of fluid into the submucosa. MATERIALS AND METHODS: In order to compare the lesion-lifting properties of several different solutions, 1 ml of each of the following solutions was injected into the submucosa of the resected porcine stomach: normal saline, 3.75 % NaCl, 20 % dextrose water, 10 % glycerin with 0.9 % NaCl plus 5 % fructose, and two sodium hyaluronate (SH) solutions. RESULTS: Significantly higher initial elevation was produced by both SH solutions, and it remained higher than that achieved by the other solutions at all times. Hypertonic solutions, especially 10 % glycerin with 0.9 % NaCl plus 5 % fructose, tended to produce and maintain greater mucosal elevation than normal saline, but the difference was not significant. CONCLUSIONS: SH solutions were the most suitable ones for producing and maintaining long-term mucosal elevation, while the superiority of hypertonic solutions over normal saline was not clearly demonstrated.

Animals↗
PubMed2004

Different mixtures of sodium hyaluronate and their ability to create submucosal fluid cushions for endoscopic mucosal resection.

BACKGROUND AND STUDY AIMS: Sodium hyaluronate (SH) is a promising submucosal injection solution during endoscopic mucosal resection, but its high cost is an obstacle to more widespread use. The aim of this study was to identify an appropriate low-cost SH solution by varying the molecular weight of SH and mixing various solutions with it. MATERIALS AND METHODS: The viscoelasticity of various SH solutions was first measured. The concentrations of two 1 % SH preparations with different molecular weights (800 kDa and 1900 kDa) were adjusted to 0.5 %, 0.25 %, and 0.125 %, using 0.9 %/3.75 % normal saline (NS), 5 %/20 % dextrose water (DW), and a glycerin solution (Glyceol): 10 % glycerin with 0.9 % normal saline plus 5 % fructose. The ability of these SH solutions to create submucosal fluid cushions (SFCs) was then investigated in the stomachs of two live minipigs. RESULTS: The 0.25 % 1900 kDa SH/NS solution and the 0.125 % 1900 kDa SH/20 % DW solution created a similar viscoelasticity to that of the 0.5 % 800 kDa SH/NS solution. The ability of these solutions to create SFCs was also similar. In addition, the 0.125 % 1900 kDa SH/Glyceol solution created similar SFCs, with a synergistic effect of increased viscoelasticity and the hypertonic nature of glycerin. CONCLUSIONS: A mixture of higher molecular weight sodium hyaluronate with a sugar solution (particularly 20 % dextrose), with or without glycerin, should be regarded as a cost-effective option for creating SFCs instead of the conventional SH solution made with the same amount of a 1 % 800 kDa SH preparation and normal saline.

Animals↗
PubMed2004

Relationship between Helicobacter pylori infection and the prevalence, site and histological type of gastric cancer.

AIM: To evaluate the relationship between Helicobacter pylori infection and gastric cancer in Japan. METHODS: This was a multicentre study conducted in various regions in Japan. A total of 6578 individuals as controls and 2503 with histologically confirmed gastric cancer were enrolled. H. pylori status was determined by enzyme-linked immunosorbent assay (ELISA) for anti-H. pylori immunoglobulin G (IgG). RESULTS: The prevalence of H. pylori infection in gastric cancer patients was markedly high in all age groups. In contrast, the rate increased with age among control subjects. The overall prevalence of H. pylori infection in control subjects was 50.2% (3300/6578) vs. 82.8% in gastric cancer patients (2072/2503) (OR = 2.47; 95% CI: 2.19-2.79). The prevalence of H. pylori in early gastric cancer was significantly higher than that in advanced gastric cancer (86.5% vs. 75.7%; OR = 2.06; 95% CI: 1.66-2.55). There were no significant differences in the prevalence of H. pylori between the intestinal and diffuse types of gastric cancer or among gastric cancer in antrum, body and cardia. CONCLUSION: H. pylori infection is strongly associated with the development of gastric cancer. The difference in odds ratios among younger and older persons with gastric cancer likely reflects the decrease in prevalence of H. pylori in the population, and is more reflective of the actual risks associated with the infection.

Adult↗
PubMed2004

Functional expression of high-affinity receptor for immunoglobulin E on mast cells precedes that of tryptase during differentiation from human bone marrow-derived CD34 progenitors cultured in the presence of stem cell factor and interleukin-6.

BACKGROUND: CD34(+) progenitor cells develop into tryptase(+), CD117(+) mast cells when cultured in the presence of recombinant human stem cell factor (rhSCF). However, spontaneous IgE receptor (FcepsilonRI) expression during human mast cell development is not well examined. OBJECTIVE: Here, the expression and function of FcepsilonRI in and on human bone marrow-derived mast cells (HBMMCs) during development were investigated. METHODS AND RESULTS: At 4 weeks of culture, predominant cells expressed high-affinity IgE receptor alpha chain (FcepsilonRIalpha) on the cell surface determined by flow cytometry, but CD117 was less expressed. Immunocytochemistry with antitryptase mAb and anti-FcepsilonRIalpha mAb revealed intracellular and surface expression of FcepsilonRIalpha at 2 weeks of culture, but tryptase was less expressed. FcepsilonRIalpha mRNA transcript preceded that of tryptase mRNA at 2 weeks of culture determined by real-time RT-PCR, and FcepsilonRIalpha, FcepsilonRIbeta, FcepsilonRIgamma, and tryptase mRNA increased along with differentiation. FcepsilonRIalpha cross-link on HBMMC and 4-week-old mast cells/mast cell precursors induced the release of IL-5 and granulocyte macrophage-colony stimulating factor, which was enhanced by rhSCF. CONCLUSION: These data indicated that HBMMC constitutively and spontaneously expressed functional FcepsilonRI subunits at the early stage of differentiation, probably because of the differences in the ability and functional property of progenitors.

Antigens, CD34↗
PubMed2004

Detection of tryptase-, chymase+ cells in human CD34 bone marrow progenitors.

BACKGROUND: Mast cells (MCs) arise from haematopoietic stem cells. We have recently reported that CD34(+) progenitors derived from human bone marrow (BM) develop into tryptase+, chymase+ MCs when cultured in the presence of recombinant human stem cell factor (rhSCF) and recombinant human IL-6 (rhIL-6). In an experiment for the expression of chymase during differentiation, chymase+ cells were detected in human BM, but tryptase+ cells were not found. OBJECTIVE: The purpose of this study was to show the appearance of chymase+ cells in CD34(+) cells with an origin different from MC differentiation. METHODS: CD34(+) cells from human BM were sorted with anti-CD117 monoclonal antibody (mAb), and cytospins of CD34(+), CD34(+)CD117(+), or CD34(+)CD117(-) were prepared. These cells were cultured with rhSCF+rhIL-6 for 12 weeks. Some of the cells were subjected to either histological stain with Wright-Giemsa or immunocytochemistry with anti-chymase mAb. Real-time RT-PCR was also performed to compare the transcriptional level of chymase from each cell preparation. RESULTS: Chymase was expressed in CD34(+) cells as well as human MCs by immunocytochemistry. Substantial CD34(+)CD117(-) cells, but not CD34(+)CD117(+) cells, were stained immunocytochemically with anti-chymase mAb. For 1 week culture with rhSCF+rhIL-6, no cells expressed chymase in any preparation. Real-time RT-PCR revealed positivity for chymase mRNA in CD34(+) cells, but it reduced at 1 week of culture, and increased as cells developed into MCs. Chymase mRNA in CD34(+)CD117(+) cells was negligible compared with that in CD34(+)CD117(-). Tryptase mRNA was below the detectable level in CD34(+) cells, and increased along with MC differentiation. After 12 weeks of culture, CD34(+)CD117(+) developed predominantly into MCs, whereas CD34(+)CD117(-) developed into monocytes/macrophages. CONCLUSION: Our findings suggested that chymase is present not only in MCs but also in CD34(+)CD117(-) BM progenitors, but that its origin is different from the MC lineage.

Antigens, CD34↗
PubMed2004

The effects of the aromatase inhibitor fadrozole hydrochloride on fetuses and uteri in late pregnant rats.

It is well known that progesterone and estrogen are essential hormones for maintaining pregnancy in most mammals. Some specific roles of progesterone for the maintenance of pregnancy have been clarified, but the role of estrogen is not well known. This study examines the effects of the aromatase inhibitor, fadrozole hydrochloride (Fad), on fetuses, uterine physical properties and the mRNA expression of the uterine enzymes that are related to collagen metabolism during late pregnancy in rats. Continuous s.c. infusion with 300 micro g/day Fad from day 14 of pregnancy (day 1=the day of sperm detection) reduced the concentration of plasma estradiol-17beta (E(2)), and did not change that of plasma progesterone, compared with controls. The treatment increased the intrauterine pressure and reduced the size and compliance of the uterine tissue framework. It also caused injuries (hematomata on the extremities) in about one-quarter of fetuses by day 20. The collagen content of the uterine ampullae was not changed by the treatment. Uterine mRNA expressions of matrix metalloproteinase-1 (MMP-1), which degrades collagens, and of lysyl oxidase (LO), which is necessary for the formation of intra- and inter-molecular cross-links of collagen, were examined by quantitative RT-PCR. The treatment with Fad had no effect on the expression of MMP-1 mRNA and increased that of LO mRNA. Daily s.c. injection with 0.2 micro g E(2) restored the changes in uterine physical properties and the mRNA expression of LO caused by the Fad treatment, and prevented fetal injury, indicating that the influences of Fad treatment are due to estrogen deficiency but not to toxicological effects of Fad. These results imply that estrogen deficiency during late pregnancy in rats obstructs development of the uterine tissue framework so as to cause fetal injury. It is possible that an increase in the uterine expression of LO gene may be involved in this obstruction.

Animals↗
PubMed2004

The effects of dissolved organic matter on the decomposition of di-n-butyl phthalate by ozone/hydrogen peroxide process.

The effects of the dissolved organic matter (DOM) on the ozone decay and the di-n-butyl phthalate (DBP) decomposition during ozone/hydrogen peroxide (O3/H2O2) process were investigated (DBP-d4 was used instead of DBP). Four surface waters, two secondary municipal sewage effluents (SMSEfs) and Suwannee river natural organic matter were used as DOM. The ozone decompositions in the DOM solutions were separated by instantaneous ozone consumption and slower ozone decay. The effect of H2O2 addition on the ozone decay was clearly observed at slower ozone decay. Ozone decomposition rate at slower ozone decay increased linearly with H2O2 dose. DBP-d4 was exponentially decreased with ozone consumption. Ozone consumption required to decompose 90% of DBP-d4 ((deltaO3)90%) in SMSEFs was higher than those in surface waters. The (deltaO3)90% per DOC of DOM values were from 22 to 23 micromole/mgC for SMSEFs and from 10 to 17 micromole/mgC for surface waters. The (deltaO3)90% values were correlated to specific ultraviolet absorbance at 254 nm (SUVA254) for surface waters.

Dibutyl Phthalate↗
PubMed2003

Spin liquid state in an organic Mott insulator with a triangular lattice.

1H NMR and static susceptibility measurements have been performed in an organic Mott insulator with a nearly isotropic triangular lattice, kappa-(BEDT-TTF)2Cu2(CN)(3), which is a model system of frustrated quantum spins. The static susceptibility is described by the spin S=1/2 antiferromagnetic triangular-lattice Heisenberg model with the exchange constant J approximately 250 K. Regardless of the large magnetic interactions, the 1H NMR spectra show no indication of long-range magnetic ordering down to 32 mK, which is 4 orders of magnitude smaller than J. These results suggest that a quantum spin liquid state is realized in the close proximity of the superconducting state appearing under pressure.

Journal Article↗
PubMed2003

Tachykinins mediate non-adrenergic, non-cholinergic excitatory neurotransmission to the hamster ileum via NK1 and NK2 receptors.

The present study was designed to investigate Substance P (SP) and a related tachykinin, Neurokinin A (NKA), contributions to the excitatory neurotransmission to the circular smooth muscle of the hamster ileum. In the presence of atropine (0.5 microM), guanethidine (3 microM) and NG-nitro-L-arginine methyl ester (L-NAME) (200 microM), electrical field stimulation (EFS) evoked a non-adrenergic, non-cholinergic (NANC) excitatory junction potential (EJP) and contraction of circular smooth muscle. Applications of SP and NKA produced depolarizing and contractile responses in a concentration-dependent fashion. The EJP and contraction were almost abolished by the non-specific tachykininergic antagonist, spantide (3 microM). Application of SP antagonist, L-732,138, (1 microM) markedly inhibited EJP (82.5%) and contraction (68.9%) and completely blocked excitatory responses produced by exogenous application of SP. While application of NKA antagonist, SR48968 (1 microM) completely blocked the depolarising and contractile responses to NKA, it only slightly inhibited those to EFS (17.2% and 31.4% respectively). These results provide evidence that, in the circular muscle of hamster ileum, endogenous tachykinins are the main NANC excitatory neurotransmitters and their action is mediated by both NK1 and NK2 receptors.

Animals↗
PubMed2003

Vegetables and fruit intake and cancer mortality in the Hiroshima/Nagasaki Life Span Study.

The association between green-yellow vegetables and fruit consumption and risk of cancer death was investigated in a prospective study of 38 540 men and women who were atomic-bomb survivors in Hiroshima and Nagasaki, Japan. Study participants completed a dietary questionnaire in 1980-1981 and were followed-up for cancer deaths until March 1998, during which time 3136 cancer deaths were identified. Daily or almost daily fruit consumption was associated with a significant 12% reduction in total cancer mortality (RR=0.88; 95% CI, 0.80-0.96 for daily intake compared with intake once per week or less). Daily or almost daily green-yellow vegetables consumption was associated with a marginally significant 8% reduction in total cancer mortality (0.92; 0.94-1.01). Green-yellow vegetables consumption was associated with a significant reduction in liver cancer mortality (0.75; 0.60-0.95). Fruit consumption was associated with a significantly reduced risk of stomach cancer and lung cancer mortality (0.80; 0.65-0.98). Green-yellow vegetables and fruit consumption was associated with a reduction in oesophageal cancer, but these associations were not statistically significant. Neither green-yellow vegetables nor fruit consumption was associated with colorectal cancer or breast cancer mortality. These results support the evidence that daily consumption of fruit and vegetables reduces the risk of total cancer, and specifically cancers of the stomach, liver, and lung.

Cohort Studies↗
PubMed2003

Kinetics of v-src-induced epithelial-mesenchymal transition in developing glandular stomach.

The oncogene function in primary epithelial cells is largely unclear. Recombination organ cultures in combination with the stable and transient gene transfer techniques by retrovirus and electroporation, respectively, enable us to transfer oncogenes specifically into primary epithelial cells of the developing avian glandular stomach (proventriculus). In this system, the epithelium and mesenchyme are mutually dependent on each other for their growth and differentiation. We report here that either stable or transient expression of v-src in the epithelium causes budding and migration of epithelial cells into mesenchyme. In response to the transient expression of v-Src or a constitutive active mutant of MEK, we observed immediate downregulation of the Sonic hedgehog gene and subsequent elimination of E-cadherine expression in migrating cells, suggesting the involvement of MAP kinase signaling pathway in these processes. v-src-expressing cells that were retained in the epithelium underwent apoptosis (anoikis) and detached from the culture. Continuous expression of v-src by, for example, Rous sarcoma virus (RSV) was required for the epithelial cells to acquire the ability to express type I collagen and fibronectin genes (mesenchymal markers), and finally to establish the epithelial-mesenchymal transition. These observations would partly explain why RSV does not apparently cause carcinoma formation, but induces sarcomas exclusively.

Animals↗
PubMed2003

Mice deficient in cytosolic phospholipase A2 are less susceptible to cerebral ischemia/reperfusion injury.

To determine the role of cytosolic phospholipase A2 (cPLA2) in infarct development, wild-type and cPLA2 knock-out mice were subjected to focal cerebral ischemia for 75 min by occluding the middle cerebral artery using nylon filament and subsequent reperfusion by withdrawing the filament. The neurological deficit severity was evaluated by a modified 4-point scale. After the reperfusion period (72 h), mice were killed, and the brains were cut into four 2 mm coronal sections using a rodent brain matrix. Sections were stained with 2% 2,3,5-triphenyltetrazolium chloride (TTC). The infarct volume was 87.19 +/- 27.54 mm3 (mean +/- SD, n = 11) in the wild-type mice and 48.20 +/- 31.32 mm3 (n = 10; P < 0.01 vs. wild-type) in the knock-out mice. Less severe functional neurological deficits were observed in knock-out mice at 72 h after ischemia when compared with wild-type. Thus, disruption of cPLA2 resulted in significant reduction of infarct area and neurological deficit severity in the MCA occlusion model. These data indicate a critical role for cPLA2 in the pathogenesis of cerebral ischemia/ reperfusion injury.

Animals↗
PubMed2003

Simplified procedure for augmentation of the sinus floor using a haemostatic nasal balloon.

Perforation of the sinus membrane is the most common complication of sinus lift augmentation. A haemostatic nasal balloon can easily separate the sinus membrane without perforating it. The use of a haemostatic nasal balloon has three major advantages: a low risk of perforation of the sinus membrane even in anatomically complex conditions, a low incidence of infection and bleeding, and a shorter operating time.

Alveolar Ridge Augmentation↗
PubMed2003

Temporal and sequential analysis of microglia in the substantia nigra following medial forebrain bundle axotomy in rat.

Dopaminergic neurons in the substantia nigra pars compacta undergo apoptosis after transection of the medial forebrain bundle. We have assessed the temporal and sequential activities of microglia in these events by examining the complement-3 (OX-42), major histocompatibility complex class II antigen presentation (OX-6) and phagocytic activity (ED1), and correlating these indicators with dopaminergic neuronal loss. Microglia in the ipsilateral substantia nigra pars reticulata evinced activation morphology at 12 h postaxotomy. Phagocytic microglia apposed dying dopaminergic neurons in the pars compacta starting at 3 days postlesion; their number increased through 14 days and slowly decreased. Nuclear chromatin condensation and significant loss of tyrosine hydroxylase-positive dopaminergic neurons occurred around 7 days postlesion. In contrast to microglial expression of interleukin-1beta and inducible nitric oxide synthase at the axotomy site, nigral microglia were interleukin-1beta and inducible nitric oxide synthase-negative. Consistently, RNase protection assays showed that interleukin-1beta and inducible nitric oxide synthase transcripts in nigra were equivocal. The present data support the idea that phagocytosis of axotomized neurons by activated microglia is not limited to dead neurons but includes dying neurons probably without cytotoxic effects of inflammatory substances, such as interleukin-1beta or nitric oxide.

Animals↗
PubMed2003

Head and neck cancer arising after endoscopic mucosal resection for squamous cell carcinoma of the esophagus.

BACKGROUND AND STUDY AIMS: It is well known that patients with head and neck cancer often have synchronous or metachronous squamous cell carcinoma of the esophagus. However, the prevalence of subsequent head and neck cancer in patients with early-stage esophageal cancer is still unknown. The aims of this study were to analyze the frequency of metachronous head and neck cancer after endoscopic mucosal resection (EMR) for esophageal cancer and to investigate whether minute iodine-unstained areas, often associated with squamous cell carcinomas, would be an index for metachronous head and neck cancer. PATIENTS AND METHODS: 99 patients with esophageal squamous cell carcinoma who underwent EMR were studied. Based on the iodine-staining pattern at initial EMR, they were categorized into those with uniform (group U) and scattered (group S) types of background mucosa. Patients were monitored endoscopically and otolaryngologically (group U, median 46 months, range 12-83 months; group S, median 44 months, range 13-80 months). RESULTS: In total, 5/99 patients (5.1 %) were found to have metachronous head and neck cancer during the follow-up, including 4/20 patients (20 %) in group S. In three cases laryngeal or hypopharyngeal cancer was found by endoscopic examination. The cumulative proportion of metachronous head and neck cancer-free subjects was significantly lower in group S than group U (P = 0.0007). CONCLUSIONS: Among patients who undergo EMR for esophageal carcinoma, those with scattered-type iodine staining of the background mucosa have an increased risk of metachronous head and neck cancer, and should therefore be closely observed. Careful endoscopic observation led to early detection of laryngeal and hypopharyngeal cancer.

Aged↗
PubMed2003

Experimental study of blood typing in immunosuppressant-free tracheal transplantation in dogs.

BACKGROUND: A previous report has noted that tracheal allotransplantation is possible using allografts without immunosuppressants. In the present study, we investigated whether blood typing is necessary in immunosuppressant-free tracheal allotransplantation in dogs. METHODS: In group 1, the blood types of paired dogs were mismatched (n=6, three pairs), while the blood types of paired dogs were matched in group 2 (n=6, three pairs). In paired dogs, an intrathoracic 5-ring tracheal segment was exchanged. No immunosuppressants were used. RESULTS: All animals survived for more than 8 weeks. In each group, different degrees of airway stenosis were observed in four dogs. However, no stenosis was observed in the other two dogs. Histologically, no vascular rejection was detected. Ciliated columnar epithelium covered the inner surface of the implanted graft in the long-term survival cases. CONCLUSIONS: In immunosuppressant-free tracheal allotransplantation, no hyperacute rejection occurred in any recipient dog whose blood type was mismatched with the donor. Blood typing was not the key factor to successful immunosuppressant-free tracheal allotransplantation. Immunosuppressant-free tracheal allotransplantation may be possible using mismatched blood type tracheal grafts.

Animals↗