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Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 55 records · Page 3Linked to original sources
PubMed2002

TNF-alpha -induced endothelial cell adhesion molecule expression is cytochrome P-450 monooxygenase dependent.

It is strongly suspected that cytokine-induced gene expression in inflammation is oxidant mediated; however, the intracellular sources of signaling oxidants remain controversial. In inflammatory bowel disease (IBD) proinflammatory cytokines, such as TNF-alpha, trigger gene expression of endothelial adhesion molecules including mucosal addressin cell adhesion molecule-1 (MAdCAM-1). MAdCAM-1 plays an essential role in gut inflammation by governing the infiltration of leukocytes into the intestine. Several groups suggest that endothelial-derived reduced NADP (NADPH) oxidase produces signaling oxidants that control the expression of adhesion molecules (E-selectin, ICAM-1, VCAM-1). In addition to NADPH oxidase, cytochrome P-450 (CYP450) monooxygenases have also been shown to trigger cytokine responses. We found that in high endothelial venular cells (SVEC4-10), multiple inhibitors of CYP450 monooxygenases (SKF-525a, ketoconazole, troleandomycin, itraconazole) attenuated TNF-alpha induction of MAdCAM-1, whereas NADPH oxidase inhibition (PR-39) did not. Conversely, E-selectin, ICAM-1, and VCAM-1 induction requires both NADPH oxidase and CYP450-derived oxidants. We show here that MAdCAM-1 induction may depend exclusively on CYP450-derived oxidants, suggesting that CYP450 blockers might represent a possible novel therapeutic treatment for human IBD.

Animals↗
PubMed2002

High insulin enhances neutrophil transendothelial migration through increasing surface expression of platelet endothelial cell adhesion molecule-1 via activation of mitogen activated protein kinase.

AIMS/HYPOTHESIS: There is increasing evidence that hyperinsulinaemia is linked with the development of atherosclerosis in patients with diabetes. However, the mechanisms by which hyperinsulinaemia causes accelerated atherosclerosis, especially with respect to leukocytes transendothelial migration, are poorly understood. We examined whether hyperinsulinaemia directly affects neutrophil transendothelial migration and surface expression of related endothelial adhesion molecules. METHODS: Experiments on the transmigration of neutrophils from healthy volunteers and from patients with Type II (non-insulin-dependent) diabetes mellitus across human umbilical vein endothelial cells cultured in insulin-rich medium using cell-culture inserts were carried out. Migrated neutrophils were quantified by measuring their myeloperoxidase activities, and the surface expression of endothelial adhesion molecules was examined using an enzyme immunoassay. RESULTS: High insulin (over 50 microU/ml for 24 h) enhanced neutrophil transendothelial migration in a dose-dependent manner. This was associated with increased expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) but not of intercellular adhesion molecule-1 (ICAM-1), P-selectin or E-selectin. Both phenomena were attenuated by pretreatment with a tyrosine kinase inhibitor, especially a mitogen-activated protein kinase inhibitor, but not by inhibitors of other second messengers. In addition, a mitogen-activated protein kinase activator, anisomycin, by itself enhanced both neutrophil transendothelial migration and PECAM-1 expression within 3 h in a dose-dependent manner. Pretreatment with nitric oxide synthase inhibitors had no effect on these events. CONCLUSION/INTERPRETATION: These results suggest that hyperinsulinaemia could accelerate atherosclerosis by directly enhancing neutrophil transendothelial migration through increasing endothelial PECAM-1 expression via mitogen-activated protein kinase activation.

Cells, Cultured↗
PubMed2002

Concentric structure of thalamic lesions in acute necrotizing encephalopathy.

Acute necrotizing encephalopathy of childhood (ANE) is characterized by multiple, symmetrical brain lesions affecting the bilateral thalami, putamina and cerebral white matter, which often show a concentric structure on CT and MRI. To reveal the pathological substrate of this finding, comparison was made between CT and necropsy findings of three fatal cases of ANE. Cranial CT demonstrated a concentric structure of the thalamocerebral lesions in one patient who died 3.5 days after the onset of encephalopathy, but not in the other two patients who died within 30 h. Neuropathological examination of postmortem brains revealed laminar changes of vascular and parenchymal pathology in all the cases. Excessive permeability of blood vessels and resultant vasogenic edema became more prominent with increasing depth from the cerebral surface. The deep portion of the lesions showed severe perivascular hemorrhage, accounting for the central high density on the CT images of one patient.

Child Welfare↗
PubMed2002

Experimental and numerical study of the colour appearance of tattoo models.

The colour of tattooed skin has been predicted by a Monte Carlo method based on the optical coefficient spectra of the skin and tattoo dyes. Slices of pig skin, a tattoo phantom and skin phantoms with different thickness were prepared, and their reflectance and transmittance spectra were measured using an integrating sphere at wavelengths varying from 400nm to 700nm. The absorption and scattering coefficient spectra of skin phantoms, pig skins and the tattoo phantom were each calculated using the inverse Monte Carlo method. The skin phantoms and pig skins were overlaid on the tattoo phantom, and the reflectance spectra of the two-layered structures were measured. The reflectance spectra of the two-layered structures were calculated from the optical coefficient spectra using the Monte Carlo method. They agreed well with the measured spectra. The colour differences between the calculated and measured spectra were also evaluated by the L*a*b* colour space distances and showed good agreement, with 3.49 for the skin phantoms and 8.27 for the pig skins.

Animals↗
PubMed2002

High insulin exacerbates neutrophil-endothelial cell adhesion through endothelial surface expression of intercellular adhesion molecule-1 via activation of protein kinase C and mitogen-activated protein kinase.

AIMS/HYPOTHESIS: The association of insulin resistance and compensatory hyperinsulinaemia with increased coronary events in diabetic patients is poorly understood. There are few publications about the direct atherogenic actions of insulin on the endothelium compared with those on vascular smooth muscle cells. The aim of this study was to elucidate whether high insulin directly affects neutrophil-endothelial cell adhesion and surface expression of endothelial adhesion molecules. We also examined what intracellular mechanisms are involved in these events. METHODS: Studies of adhesion between neutrophils from healthy volunteers and human umbilical vein endothelial cells incubated in insulin-rich medium were carried out. Adhered neutrophils were quantified by measuring their myeloperoxidase activities and surface expression of endothelial adhesion molecules was examined using an enzyme immunoassay. RESULTS: High insulin enhanced neutrophil-endothelial cell adhesion with an increase in the expression of intercellular adhesion molecule-1 but not E-selectin or P-selectin. Both phenomena were attenuated by pretreatment with protein kinase C inhibitors and a mitogen activated protein kinase inhibitor. CONCLUSIONS/INTERPRETATION: These results suggest that hyperinsulinaemia causes vascular injury by directly exacerbating neutrophil-endothelial cell adhesion through increasing endothelial expression of intercellular adhesion molecule-1 via activation of protein kinase and mitogen activated protein kinase pathways.

Cell Adhesion↗
PubMed2002

Expression of high levels of tubulin and microtubule-associated protein 2d in the neurohypophysial astrocytes of adult rat.

The hypothalamo-neurohypophysial system, containing arginine vasopressin and oxytocin, is well known to show reversible morphological reorganization for both neurons and glial cells during chronic physiological stimulation. To determine the molecular background for these morphological changes, we investigated the expression of tubulin and microtubule-associated protein (MAP) 2d in the neurohypophysial astrocytes, pituicytes of adult rats by using reverse transcription-polymerase chain reaction, western blot, and immunohistochemistry. The mRNA of MAP2d was expressed at higher levels than that of MAP2c in the neurohypophysis, cerebral cortex, and cerebellum. In contrast, predominant expression of mRNA of MAP2c was detected in the olfactory bulb. Western blot analysis showed the presence of MAP2d in the neurohypophysis, however the amount was below the detection level in the cerebral cortex and cerebellum. A double labeling study using a confocal laser scanning microscope showed intense tubulin immunoreactivity in the glial fibrillary acidic protein (GFAP)-positive pituicytes of the intact neurohypophysis. Almost no tubulin immunoreactivity was observed in the astrocytes of the intact cerebral cortex, cerebellum, and supraoptic nucleus, in contrast to strong tubulin immunoreactivity in neuronal dendrites and somata. Interestingly, intense tubulin immunoreactivity was also observed in the GFAP-positive reactive astrocytes in the immediate vicinity of the artificial lesion of the cerebral cortex. Electron microscopic observation further demonstrated the presence of a lot of microtubules in the pituicytes of intact rats.The present results demonstrate that pituicytes in the adult rat neurohypophysis expresses high levels of tubulin and MAP2d compared with normal brain astrocytes, and suggest that the ability of astrocytic morphological alteration may be at least partly ascribed to this high expression of microtubule proteins.

Animals↗
PubMed2002

Bcl-x(L) confers multi-drug resistance in several squamous cell carcinoma cell lines.

Carboplatin (CBDCA) alone or in combination with irradiation and other chemotherapeutic agents has been used for the treatment of oral squamous carcinoma. However, there are some limitations for such therapy because of inherent or acquired resistance to CBDCA. To gain some insights into the association of CBDCA resistance with Bcl-2 family level or p53 status, we established eight carcinoma cell lines, consisting of two resistant (MIT8, MIT16), two sensitive (MIT6, MIT7), and four intermediate lines. All of the five cell lines with p53 mutation belonged to the resistant approximately intermediate group, whereas two of three other lines with wild-type p53 were in the sensitive group. Interestingly, both of the two resistant cell lines showed elevated levels of Bcl-x(L), almost double that of sensitive line (MIL5), whereas either Bcl-2 or Bax-alpha level did not correlate with the CBDCA-resistance. To further verify the association between the Bcl-x(L) level and the drug resistance, two transformants (x(L)-3, x(L)-6) overexpressing Bcl-x(L) in the CBDCA-sensitive cell line MIT7 were established using the gene transfer method. Both clones showed resistance to multiple chemotherapeutic agents, including CBDCA, actinomycin D, etoposide, and mitomycin C. Moreover, MIT8 and MT16 also displayed cross-resistance to these agents. These findings suggest that Bcl-x(L) may function as one of the key components conferring multiple drug-resistance in squamous cell carcinomas.

Antineoplastic Agents↗
PubMed2002

BcI-xL antisense treatment sensitizes Bcl-xL-overexpressing squamous cell carcinoma cells to carboplatin.

Carboplatin (CBDCA) has been widely used for the treatment of oral squamous cell carcinoma (SCC). The Bcl-2 family member Bcl-xL has been demonstrated to provide resistance to chemotherapeutic agents including CBDCA. Morpholino Bcl-xL antisense oligonucleotides (oligos) were employed to down-regulate Bcl-xL in CBDCA-resistant (MIT8, MIT16) as well as CBDCA-sensitive (MIT7) SCC cell lines. The oligos were delivered to adherent cells using a scrape-load procedure. The Bcl-xL antisense reduced Bcl-xL levels without altering the level of control actin, suggesting the specificity of this agent. The addition of Bcl-xL antisense oligos substantially prevented the cell growth of both CBDCA-sensitive and-resistant cells. The CBDCA-induced partial prevention of cell growth was further augmented by the addition of the Bcl-xL, but not the control, antisense oligos. The morpholino type Bcl-xL antisense oligos may be useful for the treatment of SCC, especially multidrug-resistant tumors with enhanced Bcl-xL levels.

Antineoplastic Agents↗
PubMed2002

Kinetics and steady-state of VO2 responses to arm exercise in trained spinal cord injury humans.

STUDY DESIGN: Cross-sectional study comparing trained spinal cord injured (SCI) subjects (lesion level: L1 - T6) with healthy young subjects (CONT). OBJECTIVE: To investigate the kinetics of response in oxygen uptake (VO(2)) in human upper-body skeletal muscles, nine trained SCI subjects underwent submaximal supine arm exercises. METHOD: The SCI subjects underwent an incremental arm exercise test until exhaustion. The days after this first round of testing, breath-by-breath VO(2) and beat-by-beat heart rate (HR) on- and off-kinetics were determined during three repetitions of constant exercise at 50% of VO(2peak). The overall time course of response was determined from the half time (t(1/2)). Increased capillary blood lactate production (delta[La]b) at the onset of exercise was defined as the difference between at rest and at the end of exercise. Cardiac output (Q) was measured using the acetylene rebreathing method during the steady state of exercise. In accordance with the Fick principle, the difference in arterial-venous O(2) content (Ca-vO(2)) was defined as VO(2)/Q. RESULTS: During the steady state of the submaximal arm exercise, a more significant increase in the steady state of Q was obtained in the CONT subjects than in the trained SCI subjects: respectively, 14.9+/-1.4 l/min versus (12.7+/-0.8 l/min). There was no difference in the steady state of VO(2) between the two groups; as a result, SCI subjects had the greater Ca-v(2). Meanwhile, VO(2) on- and off-kinetics became much faster in the trained SCI subjects than in the CONT subjects. In addition, t(1/2) HR on-kinetics was not significantly different between the SCI and CONT groups. Increased Delta[La]b was closely related to larger t(1/2) VO(2) on-kinetics (r = 0.624, P < 0.05). CONCLUSION: It is concluded that the acceleration of VO(2) on- and off-kinetics in the trained SCI subjects was observed even though there was no difference in HR on- and off-kinetics between the SCI and CONT groups and a lower steady state of Q in the trained SCI subjects. VO(2) kinetics would therefore be the limiting factor in oxidative phosphorylation in the upper skeletal muscles, thereby providing a lower lactic O(2)-deficit (ie delta[La]b).

Adult↗
PubMed2002

The effects of CD40- and interleukin (IL-4)-activated CD23+ cells on the production of IL-10 by mononuclear cells in Graves' disease: the role of CD8+ cells.

The possible roles of CD8+ cells in the abnormal T cell-dependent B-cell activation in Graves' disease were investigated by analysing lymphocyte subsets in peripheral blood mononuclear cells (PBMC) and their production of soluble factors and cytokines such as IL-10 in patients with Graves' disease, Hashimoto's thyroiditis and normal controls. The PBMC were separated into CD8+ and CD8-depleted cells by magnetic separation columns, and cultured for 7 days with or without anti-CD40 monoclonal antibodies and IL-4. The culture supernatant was assayed for sCD23 and IL-10 using EIA, and the remaining cells were analysed by flow cytometry. Stimulation with anti-CD40 antibody together with IL-4 increased sCD23 levels and the number of CD23+ cells. The latter was further augmented by depletion of CD8+ cells. This combination of B cell stimulants increased production of IL-10 by PBMC from patients with Graves' disease. The CD40- and IL-4-activated production of IL-10 was decreased by CD8+ cell depletion. In contrast, constitutive production of IL-10 was increased after CD8+ cell depletion in a group of patients with low basal secretion levels (<35 ng/ml). It was, however, decreased in a group with higher basal production levels, but such a relationship was not found in the normal control group. Thus, T cell-dependent B-cell activation via a CD40 pathway activates CD23+ cells, leading to over-production of IL-10 and a shift of the Th1/Th2 balance to Th2 dominance, while CD8+ cells may suppress this activation to counteract the Th2 deviation in Graves' disease.

Adult↗
PubMed2002

DNA analysis of nosocomial infection by Enterobacter aerogenes in three cases of septicaemia in Japan.

Ceftazidime-resistant Enterobacter aerogenes was isolated from blood cultures of three patients with fever. DNA analysis using pulsed-field gel electrophoresis and ribosomal RNA gene restriction digest pattern analysis revealed that the strains were clonally similar to each other with a 79.3-96.0% homology. The same strain of E. aerogenes was isolated from a three-way stopcock connected to the indwelling catheter in one of the patients at a concentration of 45 cfu/mL. A similar strain was also isolated from the urine of one other patient on the same floor. The data suggest that E. aerogenes caused septicaemia via low bacterial contamination of a three-way stopcock in a peripheral drip intravenous infusion system in at least one patient, and that the outbreak of E. aerogenes infections was due to clonally-related strains.

Adult↗
PubMed2002

Mesial temporal lobe epilepsy with lateral temporal lobe abnormalities in magnetoencephalography and glucose metabolism.

Magnetoencephalography (MEG) and positron emission tomography (PET) revealed abnormal findings in the lateral temporal lobe of a 22 year old female with mesial temporal lobe epilepsy. Electroencephalography identified the epileptogenic focus in the left mesial temporal lobe and standard anterior temporal lobectomy resulted in a good surgical outcome. These discrepancies can be explained by the presence of anatomical and functional pathways between the mesial and lateral temporal structures, or pathophysiological abnormalities in both the mesial and lateral temporal lobes. Careful evaluation is necessary for analysis of MEG and PET findings in patients with temporal lobe epilepsy.

Adult↗
PubMed2002

Age related expression of Werner's syndrome protein in selected tissues and coexpression of transcription factors.

AIMS: Werner's syndrome (WS) is an uncommon autosomal recessive disease resulting from mutational inactivation of human WRN helicase, Werner's syndrome protein (WRNp). Patients with WS progressively develop a variety of aging characteristics after puberty. The aim of this study was to determine the distribution of WRNp and the expression of the transcription factors regulating WRN gene expression in a variety of human organs in an attempt to understand the WS phenotype. METHODS: Tissue specimens were obtained from 16 controls aged from 27 gestational weeks to 70 years of age and a 56 year old female patient with WS. The distribution of WRNp and the expression of the transcription factors regulating WRN gene expression-SP1, AP2, and retinoblastoma protein (Rb)- were studied in the various human organs by immunohistochemical and immunoblot analyses. RESULTS: In the healthy controls after puberty, high expression of WRNp was detected in seminiferous epithelial cells and Leydig cells in the testis, glandular acini in the pancreas, and the zona fasciculata and zona reticularis in the adrenal cortex. In addition, the SP1 and AP2 transcription factors, which regulate WRNp gene expression, appeared in an age dependent manner in those regions where WRNp was expressed. In controls after puberty, SP1 was expressed in the testis and adrenal gland, whereas AP2 was expressed in the pancreas. CONCLUSIONS: These findings suggest that the age specific onset of WS may be related to age dependent expression of WRNp in specific organs.

Adolescent↗
PubMed2002

Improved filler-matrix coupling in resin composites.

Ineffective silane coupling between filler and matrix within dental composites is prone to accelerated in vivo degradation. In this study, we examined to what degree a procedure involving chemical decontamination of filler prior to silanization could improve the filler-matrix bonding, and thus the physico-mechanical properties, of composites. X-ray photoelectron spectroscopy revealed that filler-matrix coupling largely depended upon siloxane bridge (Si-O-Si) formation between the silica surface and the silane molecule, rather than on intermolecular bonding between adjacent silane molecules. Pre-silanization decontamination based upon boiling silica in 0.05-5% sodium peroxodisulfate, followed by ultrasonic rinsing in acetone, most effectively decontaminated filler. Consequently, it significantly improved the bonding of silane molecules to silanol groups at the silica surface. Experimental composites produced following pre-silanization decontamination of filler revealed a diametral tensile strength that was resistant to degradation by thermocycling.

Composite Resins↗
PubMed2002

Nuclear export of glucocorticoid receptor is enhanced by c-Jun N-terminal kinase-mediated phosphorylation.

The c-Jun N-terminal kinase (JNK) phosphorylates the glucocorticoid receptor (GR) and inhibits GR-mediated transcription. However, the biological effect of the GR phosphorylation remains unknown. Here we demonstrate that activated JNK phosphorylates human GR at Ser226 and enhances its nuclear export after withdrawal of a ligand for GR, dexamethasone. At 1 h after dexamethasone withdrawal, green fluorescent protein-GR molecules were mostly retained at the nucleus, whereas UV exposure enhanced its nuclear export, and approximately 30-40% of cells revealed distinct nuclear export. JNK overexpression alone mimics UV exposure and enhanced GR export accompanied by inhibition of GR-mediated transcription. However, mutation of the Ser226 JNK phosphorylation site in GR abrogated UV-mediated enhancement of GR nuclear export. Furthermore, overexpression of a dominant negative SEK1 mutant also abrogated the effects of UV exposure on GR export. Taken together, these findings suggest that JNK-mediated phosphorylation of the GR-Ser226 enhances GR nuclear export and may contribute to termination of GR-mediated transcription.

Active Transport, Cell Nucleus↗
PubMed2002

Potential role of activin A in follicular development during the second half of pregnancy in the golden hamster: utero-placental source of activin A.

Numerous antral follicles develop during the second half of pregnancy in the golden hamster. However, mechanisms regulating follicular development during this period are unknown. Because inhibin and activin are related to follicular development, these hormones were studied to gain insight into any potential roles in follicular development. Plasma inhibin A and B suddenly increased from day 8 of pregnancy, reached peak levels on day 10 and gradually declined to term. Plasma activin A gradually increased from day 8 to day 15 of pregnancy, and this was followed by an abrupt decrease at day one of lactation. Ovariectomy on day 12 of pregnancy rapidly reduced plasma inhibin A and B, but not activin A levels. Hysterectomy or placentectomy on day 12 of pregnancy caused an abrupt decrease in the levels of plasma activin A and FSH, but not inhibin A and B at 6 h after surgery. Hysterectomy also induced atresia of large antral follicles at 24 h after surgery. These results indicate that antral follicles are the main source of circulating inhibin A and B, whereas uteri and placentae are the main source of circulating activin A. These results suggest that increased levels of activin A may be involved in folliculogenesis in the ovary during the second half of pregnancy in the golden hamster.

Activins↗