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M Iizuka

Publications and source records attributed to M Iizuka.

At least 19 recordsLinked to original sources
PubMed2006

Excitotoxicity mediated by Ca2+-permeable GluR4-containing AMPA receptors involves the AP-1 transcription factor.

Cells preferentially expressing GluR4-containing alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors are particularly sensitive to excitotoxicity mediated through non-N-methyl-D-aspartate receptors. However, the excitotoxic signalling pathways associated with GluR4-containing AMPA receptors are not known. In this work, we investigated the downstream signals coupled to excitotoxicity mediated by Ca2+-permeable GluR4-containing AMPA receptors, using a HEK 293 cell line constitutively expressing the GluR4flip subunit of AMPA receptors (HEK-GluR4). Glutamate stimulation of GluR4-containing AMPA receptors decreased cell viability, in a calcium-dependent manner, when the receptor desensitisation was prevented with cyclothiazide. The excitotoxic stimulation mediated through GluR4-containing AMPA receptors increased activator protein-1 (AP-1) DNA-binding activity. Inhibition of the AP-1 activity by overexpression of a c-Jun dominant-negative form protected HEK-GluR4 cells against excitotoxic damage. Taken together, the results indicate that overactivation of Ca2+-permeable GluR4-containing AMPA receptors is coupled to a death pathway mediated, at least in part, by the AP-1 transcription factor.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2004

Elemental diet modulates the growth of Clostridium difficile in the gut flora.

BACKGROUND AND AIMS: Tube feeding is regarded as a risk factor for Clostridium difficile-associated diarrhoea. Recently, we reported that C. difficile toxin was frequently found in patients receiving an elemental diet. The present study was conducted to clarify whether elemental diets are associated with the growth of C. difficile in the gut flora. METHODS: C. difficile was cultured for 72 h in various concentrations of elemental diet containing 3% thioglycollate, and the growth rate or activity of C. difficile was evaluated by Gram stain or by measuring optical density at 560 nm. Faecal samples from 10 healthy adults were cultured in elemental diet + 3% thioglycollate. RNA was extracted from faeces with glass powder, which can eliminate PCR inhibitors, and mRNA of C. difficile toxin B was measured by reverse transcription PCR. RESULTS: Maximum OD560 value during culture in thioglycollate-containing elemental diet was 2.4 times higher than that in thioglycollate alone (P = 0.0163). Viability of C. difficile was decreased in thioglycollate but not in thioglycollate-containing elemental diet. Toxin B mRNA was detected in five faecal samples (50%) before culture and in all samples after culture. CONCLUSIONS: Our results suggest that an elemental diet can modulate the growth of C. difficile in the gut flora.

Adult↗
PubMed2002

Corneodesmosin DNA polymorphisms in MHC haplotypes and Japanese patients with psoriasis.

In order to examine the relationship between corneodesmosin (CDSN) and psoriasis we have determined the presence of CDSN polymorphisms by DNA sequencing in (a) nine B-LCL cell lines of major histocompatibility complex ancestral haplotypes known to be associated with psoriasis vulgaris including 13.1AH, 46.1AH, 46.2 and 57.1AH, and in (b) a group of 267 unrelated individuals comprising Japanese psoriasis patients (n = 101) and Japanese subjects without the disease (n = 166). Three novel CDSN gene sequences were identified. In addition, we have classified the 18 alleles into seven main groups based on phylogeny of non-synonymous substitutions. However, we have found no statistically significant differences between the patients and the unaffected individuals in any of these groups. These findings indicate that CDSN is not a major psoriasis susceptibility gene.

Alleles↗
PubMed2001

Respiratory activity in glossopharyngeal, vagus and accessory nerves and pharyngeal constrictors in newborn rat in vitro.

1. Previously, in a brainstem-spinal cord-rib preparation from neonatal rats we demonstrated that a decrement in extracellular pH (from about 7.4 to 7.1) caused expiratory activity in an internal intercostal muscle (IIM) during the first half of the expiratory phase (Ea). As the initial step in finding nerves or muscles firing during the second half of the expiratory phase (Eb), the patterns of activity in the glossopharyngeal, vagus and accessory nerves were examined in the present study. 2. Since the emerging motor rootlets of these three nerves (> 20; collected into about 10 bundles before the jugular foramen) are distributed in a continuous fashion from rostral to caudal levels of the brainstem, visual identification was impossible. Therefore, antidromic compound action potentials evoked by stimulation of the glossopharyngeal nerve (IX), the pharyngeal branch of the vagus nerve (PhX), the superior laryngeal nerve (SLN), the cervical vagus nerve (CX) and the accessory nerve (XI) were recorded from the peripheral stumps of the various rootlets. Nerve rootlets could be categorised into rostral, intermediate and caudal groups (rostIX-XI, intIX-XI, caudIX-XI). The rostIX-XI rootlets showed their largest potential on IX stimulation, while the intIX-XI and caudIX-XI rootlets showed their largest potentials on CX stimulation. The intIX-XI rootlets showed larger potentials on PhX and SLN stimulation than the caudIX-XI rootlets. 3. Activity was recorded simultaneously from the central stumps of the rootlets in the above three groups. Most rootlets showed inspiratory bursts. Under low pH conditions, all representatives of group rostIX-XI, most of intIX-XI and about half of caudIX-XI showed additional bursts during the Ea phase. Groups intIX-XI and caudIX-XI but not rostIX-XI also showed discrete bursts during the Eb phase in some preparations. In general, expiratory activity was prominent in intIX-XI. The spinal branch of XI showed no consistent respiratory activity. 4. Since the intIX-XI rootlets showed Eb bursts and large antidromic potentials on stimulation of PhX and SLN (which innervate the inferior pharyngeal constrictor muscle (IPC)), electromyograms were recorded from the rostral and caudal parts of IPC (rIPC and cIPC). Under low pH conditions, cIPC showed bursts during the Ea and Eb phases, while rIPC showed bursts predominantly during the Eb phase. 5. These results indicate that recording from rIPC would be a useful way of examining the neuronal mechanisms responsible for Eb phase activity.

Accessory Nerve↗
PubMed2001

The effective size of fluctuating populations.

We consider a Wright-Fisher model whose population size is an autocorrelated stochastic process. Our interest is in the effects of autocorrelated fluctuations of the population size on the effective size. We define the inbreeding effective size and the variance effective size and show that these effective sizes are the same for this model. In the literature, it is said that the effective size is equal to the harmonic mean of population size when the size fluctuates. We will show, however, that the effective size is not the same as the harmonic mean of population size unless the fluctuations of population size are uncorrelated. The effective size is larger (resp. smaller) than the harmonic mean when the fluctuations of population size are positively (resp. negatively) autocorrelated. Further, we obtain some asymptotic expressions for effective size when the population size is very large and/or the autocorrelation of the fluctuation is very strong.

Animals↗
PubMed2001

Lymph folliculitis in ulcerative colitis.

Preferential involvement of the appendix has recently been confirmed in ulcerative colitis. Since the appendix is an aggregate of lymph follicles, this new observation implies a critical role of the lymph follicles, of both the large bowel and the appendix, in an etiopathogenesis of ulcerative colitis. This report presents two cases of ulcerative colitis in which lymph folliculitis and lymphoid hyperplasia were observed. Lymph folliculitis was observed endoscopically in a border between an established lesion and an uninvolved area. Case 1, proctitis type, relapsing remitting, mild in severity, showed lymph folliculitis in a proximal border of an established rectal lesion. Case 2, with left-sided colitis, mild in severity, had a skip appendiceal orifice inflammation. Lymph folliculitis was observed in the cecum surrounding established appendiceal orifice inflammation. In both cases, lymphoid hyperplasia was observed in an uninvolved area with clear vascular patterns. These two cases clearly demonstrate the involvement of gut lymph follicles in ulcerative colitis. Lymph folliculitis and/or lymphoid hyperplasia was proposed to be early lesions in ulcerative colitis. In addition, the need for microbiology targeting lymph follicles of the large bowel and appendix is stressed in order to disclose the casual microbial agents in ulcerative colitis.

Adult↗
PubMed2001

Staphylococcus aureus in inflammatory bowel disease.

BACKGROUND: The potential role of superantigens in inflammatory bowel disease (IBD), particularly Crohn disease, has been broached in studies of the functions of T cell receptors. Staphylococcal cells have been found in intestinal lymph follicles of IBDs. To clarify a role of staphylococcal superantigens in IBD, we attempted to determine whether Staphylococcus aureus could be detected in intestinal mucosa, including surgical specimens and lymph follicles of initial cases. METHODS: One-hundred-and-six colonic and ileal specimens were obtained from 38 Crohn disease, 25 ulcerative colitis and 36 non-IBD patients through therapeutic surgery or endoscopic biopsy. In Crohn disease, 23 surgical specimens and 11 biopsy specimens from initial cases were included. DNA was extracted with phenol-chloroform after homogenization and proteinase K treatment in 73 mucosal specimens. Using an inverted microscope, lymph follicle tissue was microdissected from the remaining 33, mostly biopsy, specimens. DNA was then extracted by freeze-thawing. A coagulase gene characteristic of S. aureus was sought. A nested polymerase chain reaction was performed utilizing primers that amplify a region of the coagulase gene. Polymerase chain reaction products were analyzed with polyacrylamide gel electrophoresis. RESULTS: Only one surgically resected colonic specimen, from a 42-year-old male ulcerative colitis patient, registered positive staphylocoagulase amplification. CONCLUSIONS: Staphylococcal superantigens are not involved in either the early lesions or the established lesions of Crohn disease. However, S. aureus infection occasionally may occur during the course of IBD.

Adult↗
PubMed2001

No evidence of persistent mumps virus infection in inflammatory bowel disease.

BACKGROUND AND AIM: There is controversy regarding whether paramyxovirus infection is causally associated with inflammatory bowel disease (IBD). The latest cohort study claimed that atypical measles and mumps infections in childhood may be risk factors for later IBD. This study was conducted to clarify the validity of a causal link between persistent mumps virus infection and IBD. SUBJECTS AND METHODS: (1) Amplification of the mumps virus genome was performed in both intestinal specimens (ulcerative colitis 15, Crohn's disease 15, control 10) and peripheral blood lymphocytes (PBL) (ulcerative colitis seven, Crohn's disease six, control three) by reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern hybridisation using primers specific to the viral genome encoding phosphoprotein or haemagglutinin-neuraminidase. (2) Titre of serum antimumps IgG was measured in 16 patients with ulcerative colitis, in 16 patients with Crohn's disease, and in 16 normal controls using an enzyme linked immunosorbent assay. RESULTS: (1) The mumps virus genome was not detected by RT-PCR in intestinal specimens or PBL in any case. (2) Antimumps IgG titre was positive in 7/16 ulcerative colitis, 10/16 Crohn's disease, and 11/16 control specimens. The mean (SEM) titre of antimumps IgG was 12.281 (7.831) in ulcerative colitis, 7.675 (1.608) in Crohn's disease, and 8.637 (1.969) in controls, with no significant difference between the three groups. CONCLUSION: We could not find any evidence to support a causal link between persistent mumps virus infection and IBD.

Adolescent↗
PubMed2001

Bufadienolides and a new lignan from the bulbs of Urginea maritima.

Thirty three compounds were obtained from the bulbs of Urginea maritima (Liliaceae). The compounds were identified by means of fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H-NMR), (13C-NMR), nuclear overhauser effects (NOE) and two dimensional (2D) NMR. Ten of them were new natural compounds. Nine were bufadienolides and only one was lignan in these compounds.

Bufanolides↗
PubMed2001

Identification of putative gene encoded on ORF16 of the 81 kb contig of Arabidopsis thaliana chromosome III as alpha-mannosidase.

We isolated cDNA corresponding to open reading frame (ORF) 16 of the 81 kb contig of Arabidopsis thaliana chromosome III [Quigley., Nucleic Acids Res., 24, 4313-4318 (1996)] and expressed alpha-mannosidase activity in tobacco suspension-cultured cells, which revealed that ORF16 encodes alpha-mannosidase. We also suggested that Arabidopsis harbors three genes encoding alpha-mannosidase by homology search against the database.

Journal Article↗
PubMed2001

Electrode reaction of Pu3+/Pu couple in LiCl-KCl eutectic melts: comparison of the electrode reaction at the surface of liquid Bi with that at a solid Mo electrode.

The electrode reaction of Pu3+/Pu couple at the interface between LiCl-KCl eutectic melt containing PuCl3 and liquid Bi phase was investigated by cyclic voltammetry at 723, 773 and 823 K. For comparison, the system was also studied using a solid Mo electrode in place of the liquid Bi electrode. It was found that the electrode reaction of Pu3+/Pu couple at the Bi electrode was almost reversible. The redox potentials of Pu3+/Pu couple at the liquid Bi electrode in the LiCl-KCl eutectic melt containing 0.87 wt% PuCl3 (0.0014 mole fraction) at 723, 773 and 823 K were observed to be more positive by 0.575, 0.572 and 0.566 V, respectively, than those at the Mo electrode. These differences in potential were thermodynamically analyzed by assuming a lowering of the activity of Pu in Bi phase according to the alloy formation of PuBi2.

Journal Article↗
PubMed2001

[Whole-body MR imaging for evaluation of bone marrow cellularity in aplastic anemia].

The aim of this study was to investigate the usefulness of whole-body MRI(WB-MRI) in the evaluation of cellularity in bone marrow and the distribution of fatty marrow in aplastic anemia. WB-MRI was performed on five patients with aplastic anemia who ranged in age from 62 to 70 years of age, and on four controls with malignant lymphoma who ranged in age from 59 to 67 years. Coronal images were obtained using a body coil with an FOV of 48 cm x 48 cm, and with both fast short T1 inversion recovery(STIR) and spin-echo T1-weighted(T1-WI) in three regions: (1) head to thorax, (2) abdomen to pelvis, and (3) lower extremities. The findings on WB-MRI were compared with those of histological studies of bone marrow at the sternum and the posterior iliac crest. The results were as follows: (1) there was a correlation between the cellularity of histological studies of bone marrow and signal intensity on WB-MRI; (2) WB-MRI could detect the activity of bone marrow; and (3) in a comparison of signal intensity in aplastic anemia and control subjects, there were differences of signal intensity in the central marrow.

Aged↗
PubMed2001

Tsutsugamushi disease in Kanagawa Prefecture, Japan: clinical report of two cases and survey of other incidences in 1998.

Tsutsugamushi disease is characterized by the early appearance of a black crust at the bitten area and the subsequent development of macular or macropapular rush on the whole body with high fever. While treatment with tetracycline derivatives and chloramphenicols is effective, delayed diagnosis or inappropriate treatment will lead to fatality. In this report, we describe two typical cases of tsutsugamushi disease and discuss other incidences in Kanagawa Prefecture, Japan, in 1998. One of the present two patients was diagnosed to be a case of the new type by Kawasaki strain of Rickettsia tsutsugamushi, while responsible strain was not identified for the other case. Since the disease is spreading widely even to suburban areas, we emphasize the need to consider the possible diagnosis of tsutsugamushi disease in patients with generalized eruption and high fever.

Anti-Bacterial Agents↗