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Biomedical subjects

T Saitoh

Publications and source records attributed to T Saitoh.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Helicobacter pylori infection and histological types of gastric cancer].

The relationship between Helicobacter pylori (H. pylori) infection and gastric cancer was evaluated clinicopathologically by histological types of gastric cancer (intestinal or diffuse type). Histological findings of resected stomach tissues and serum anti-H. pylori IgG antibody titers obtained in patients with early gastric cancer revealed H. pylori infection and associated inflammatory changes in all cases, irrespective of histological types of cancer, and suggested that diffuse type cancer occurs in the mucosa with marked inflammation at a relatively early stage of H. pylori infection, while intestinal type cancer occurs at a relatively late stage of infection in parallel with the progression of mucosal atrophy and intestinal metaplasia. Results of immunohistochemical staining showed high incidence of secretory components in and around cancer foci, suggesting that immunological mechanisms for H. pylori infection play a role in the development of gastric cancer regardless of its histological type.

Adenocarcinoma↗
PubMed1999

[Anesthetic management of a patient with Ludwig's angina].

A 71-year-old woman with cellulitis of the floor of the mouth, referred to as "Ludwig's angina", underwent emergency tracheostomy under general anesthesia, for the control of airway narrowing caused by sublingual and submandibular swelling with tongue elevation. Because difficult airway had been suspected by preoperative assessment, feasible options of intubation in our hospital, including laryngeal mask, fiberoptic intubation and transtracheal jet ventilation, were prepared prior to induction of anesthesia. Anesthetic induction was carried out with propofol and suxamethonium, and subsequently tracheal intubation could be performed with difficulty under condition of partial visualization of vocal cord. Anesthetic maintenance with local anesthesia and continuous infusion of propofol 6 mg.kg-1.hr-1 was carried out during tracheostomy procedure, and this procedure was done uneventfully. Because airway control still remains a top priority in Ludwig's angina, feasible options of airway control should be prepared before induction of anesthesia if tracheostomy was required in a patient with this disease.

Aged↗
PubMed1999

Production of secretory component and pathogenesis of gastric cancer in Helicobacter pylori-infected stomach.

The purpose of this study was to examine the production of secretory component (SC) and immunoglobulin A (IgA) in the gastric mucosa with Helicobacter pylori infection and to investigate the influence of immunological reactions on various phases of infection (gastritis, intestinal metaplasia, gastric cancer). Production of SC and IgA was assessed by immunohistochemical staining in (1) endoscopic biopsy samples of H. pylori-eradicated cases (n = 25), and (2) surgically resected stomach tissues of H. pylori-positive gastric cancer cases, intestinal type (IGC, n = 25) and diffuse type (DGC, n = 25). Before eradication therapy, all samples showed positive staining of SC and IgA in epithelial cells, and IgA was also positive in plasma cells in the mucosal layer. H. pylori bacteria were positively stained for SC and IgA. After treatment, the degree of SC and IgA staining in epithelial cells was reduced with successful eradication; but with intestinal metaplasia, SC staining was positive regardless of the results of treatment. In nonmetaplastic mucosa, SC-positive cells were increased in the glandular neck zone to the surface mucosal layer; and the intensity of SC staining was increased in proportion to the degree of mucosal inflammation and IgA-positive cell aggregation. In intestinal metaplasia, SC was positive irrespective of the degree of inflammation. Most cancer foci also showed positive staining of SC, irrespective of histological type. Production of SC and IgA was thought to be a specific reaction against H. pylori infection, occurring from the early to the late stages and not limited to intestinal metaplasia. It was suggested that immunological reactions against H. pylori infection might generally be involved with the pathogenesis of intestinal metaplasia and both histological types of gastric cancer (IGC and DGC).

Gastric Mucosa↗
PubMed1998

Protective effects of vasoactive intestinal peptide against delayed glutamate neurotoxicity in cultured retina.

The effects of vasoactive intestinal peptide (VIP) on glutamate-induced delayed death were examined using the primary cultures of rat retinal neurons. Effects of VIP on glutamate-induced neurotoxicity were evaluated by double staining with fluorescein diacetate and propidium iodide. Glutamate (1 mM) was applied to the culture for 10 min in the presence and absence of VIP, and visible cells enumerated 24 h after culture in normal medium. Effects of VIP on increase in the intracellular Ca2+ concentration and currents induced by glutamate in retinal neurons were investigated using the Ca2+ image analyzing system with fura-2 and whole-cell patch-clamp recording, respectively. The cAMP contents in retinal cultures were measured by radioimmunoassay. VIP (10 nM-1 microM) dose-dependently protected against glutamate-induced neurotoxicity in cultured retinal neurons. Protection by VIP (100 nM) against glutamate (1 mM)-induced neurotoxicity was antagonized by VIP6-28 (1 microM), a VIP antagonist, and H-89 (100 nM and 1 microM), a protein kinase A inhibitor. However, VIP had no effect on glutamate-induced inward currents nor glutamate-induced increase in the intracellular Ca2+ concentration. A 10-min exposure of VIP (100 nM) with glutamate (1 mM) resulted in an increase in the cAMP level to 446+/-58 from 22+/-1 pmol/mg protein. These findings suggest that VIP protects against the glutamate-induced neurotoxicity in retinal cultures by elevating the cAMP level via VIP receptors and thereby activating protein kinase A.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1998

Radio-sensitive murine thymoma cell line 3SB: characterization of its apoptosis-resistant variants induced by repeated X-irradiation.

3SB, a mouse thymoma cell line, is one of the most radio-sensitive cells (D0 = 0.3 Gy), and its rapid apoptosis (4 h after 5 Gy irradiation, 90% apoptosis) seems to play a decisive role in enhancing the radiosensitivity. To understand the molecular mechanisms underlying extremely high radiosensitivity and rapid apoptosis, we attempted to isolate X-ray-resistant (XR) variants from 3SBH5, a stable subclone of 3SB, by repeating exposure of the cells to 2-5 Gy X-rays. Four independent stable XR variants, R111, R223, R316 and R429, were isolated by the repeated irradiation protocols. All XR cells possessed about 3 times higher D10 values than that of their parental 3SBH5. They were also resistant to apoptosis; only 10% cells underwent apoptosis 4 h after 5 Gy irradiation. The p53 protein was induced in all the cell lines after 5 Gy X-irradiation. These variants showed a cross resistance to a chemical reagent daunorubicin (DNR) that is known to be involved in the ceramide-mediated apoptosis. DNR, as well as C2-ceramide (5 muM) induced apoptosis in parental 3SBH5 cell, but not in two XR variants, R233 and R316 cells. Present result suggests that the induction of X-ray resistance by repeated X-irradiation might be achieved, at least partly, by the enhanced resistance to the ceramide-mediated apoptosis.

Animals↗
PubMed1998

Human parvovirus B19 as a causative agent for rheumatoid arthritis.

Human parvovirus B19 (B19) DNA was detected in the synovial tissues in 30 of 39 patients with rheumatoid arthritis (RA), and infrequently in those with osteoarthritis and traumatic joints. On the other hand, the expression of the B19 antigen VP-1 was specific (27/27) in RA synovium with active synovial lesions, but not in osteoarthritis and controls. The target cells of B19 were macrophages, follicular dendritic cells, T cells, and B cells, but not synovial lining cells in the synovium. B19-negative bone marrow cells, tonsil cells, and macrophage cell line U-937 cells became positive for the expression of VP-1, and more productive for interleukin 6 and tumor necrosis factor alpha when cocultured with RA synovial cells. The expression of VP-1 and the production of interleukin 6 and tumor necrosis factor alpha was significantly inhibited by the addition of neutralizing antibody for B19, suggesting that B19 detected in RA synovial cells is infective. B19 is involved in the initiation and perpetuation of RA synovitis, leading to joint lesions.

Antigens, Viral↗
PubMed1998

Differential expression of protein kinase C -alpha and -betaII in rat septum and changes following fimbria-fornix lesion.

Protein kinase C (PKC)-alpha and -betaII are expressed specifically and differentially in the septal formation. Following unilateral fimbria-fornix lesions, there was a marked reduction in punctiform PKC-alpha immunoreactivity in the lateral septum and in the number of PKC-betaII immunoreactive neurons in the medial septum and the lateral septum, while some PKC-alpha and PKC-betaII immunoreactive glia-like cells were observed in the lateral septum. The response of each PKC isozyme to this lesion supports the suggested role for PKC in the plasticity of the central nervous system.

Animals↗
PubMed1998

Coincidental occurrence of pernicious anemia and mycosis fungoides in two elderly males.

We experienced two rare cases of pernicious anemia that presented in the course of mycosis fungoides in elderly males. Pernicious anemia has recently been reported to be caused by autoimmune gastritis that produces autoantibodies to gastric parietal cells and intrinsic factor. Immunological abnormalities in mycosis fungoides are reported to induce autoimmune diseases (i.e., autoimmune hemolytic anemia, anti-phospholipid antibody syndrome, arthritis, myasthenia gravis, necrotizing vasculitis, and vitiligo); the pernicious anemia in our two patients may have been closely related to the mycosis fungoides.

Aged↗
PubMed1998

Advantages of immunostaining over DNA analysis using PCR amplification to detect p53 abnormality in long-term formalin-fixed tissues of human colorectal carcinomas.

To study the appropriate period for formalin fixation in order to detect p53 abnormalities in formalin-fixed tissue, we used seven surgically resected human colorectal cancer specimens. The immunohistochemical reactivity of p53 immunostaining and amplification of DNA by polymerase chain reaction (PCR) of the p53 gene were compared after various periods of 10% formalin fixation (1 day, and 1, 2, 4, and 8 weeks). For comparative immunostaining, we used the monoclonal antibody Ki-67 (MIB-1), and for comparative polymerase chain reaction (PCR), K-ras at codon 12 was amplified. Immunostaining was performed by the streptavidin-biotin method with microwave retrieval, and PCR amplifications were performed by the nested PCR method. p53 and Ki-67 immunoreactivity did not change essentially for up to 2 weeks and 1 week, respectively, of formalin fixation. PCR amplification for p53 at exon 8 and K-ras at codon 12 was successful until 1 day and 2 weeks, respectively, of formalin-fixation for the specimens of all seven cases. Thereafter, the amplification tended to worsen as the fixation time lengthened. Further, the DNA was more successfully amplified in the second PCR than in the first. These results suggest that to detect p53 abnormality in specimens that have been formalin-fixed for long periods, immunohistochemical staining may have advantages over DNA analysis with PCR amplification.

Colorectal Neoplasms↗
PubMed1998

Successful graft replacement of the descending aorta after an extended reconstruction of the ascending and transverse aorta in a patient with Marfan's syndrome.

A 27-year-old man with Marfan's syndrome underwent a total aortic graft replacement in three separate stages. Initially the abdominal aorta was replaced, followed by the ascending aorta and aortic arch, and finally the residual portion. The extensive reconstruction of both the ascending and transverse aorta at the second operation, even though no dissection was present in the aortic arch, reduced the risk of the subsequent operation since the same surgical approach did not have to be used.

Adult↗
PubMed1998

Histopathological study of the use of freeze-dried allogenic dentin powder and True Bone Ceramic as apical barrier materials.

The biocompatibility of freeze-dried allogenic dentin powder and True Bone Ceramics (TBC), the latter prepared by incineration of bovine bone, as apical barrier materials was evaluated histopathologically in dogs. After pulpectomy, 80 root canals of 53 dog premolar teeth were prepared, and each material was tightly packed to the apical stop area. The remainder of the canal was filled with guttapercha by the lateral condensation method. Control teeth were filled by the lateral condensation method using gutta-percha without constructing apical barriers. In both the teeth filled with the dentin powder and those filled with TBC, multinucleate giant cells appeared on the bone resorption surface and the surface of the root canal wall, and marked bone resorption and positive tartrate-resistant acid phosphate staining were observed. Hard tissue had formed on the root canal wall and the filling material after 3 months. These findings suggest that the test materials are nonirritative and compatible with periapical tissue, and that they may be useful and clinically applicable as apical barrier materials.

Animals↗
PubMed1998

Role of nitric oxide and prostaglandin in the protective effect of pibutidine hydrochloride, a novel histamine H2-receptor antagonist, on the gastric mucosal lesions in rats.

1. The role of endogenous nitric oxide (NO) and prostaglandins (PGs) in the gastric mucosal protective action of pibutidine hydrochloride (IT-066), a novel histamine H2-receptor antagonist, was investigated in a 0.15 N hydrochloride (HCl) + 60% ethanol (EtOH)-induced gastric lesion model. 2. The 0.15 N HCl + 60% EtOH-induced lesion formation was reduced significantly by IT-066 (3 mg/kg, PO), NOR3 (spontaneous NO releaser; 0.03-0.1 mg/kg, SC) or PGE2 (0.01 mg/kg, PO) but was not reduced by famotidine (1-10 mg/kg, PO). 3. Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) (3 mg/kg, IV), an inhibitor of NO synthase, inhibited the protective action of IT-066 (3 mg/kg, PO), and the inhibitory effect of L-NAME was reversed by L-arginine (300 mg/kg, IV). The protective effect of PGE2 (0.01 mg/kg, PO) was not affected by the pretreatment with L-NAME (3 mg/kg, IV). 4. Infusion of carboxy-PTIO (1 mg/kg/min), a direct NO scavenger, inhibited the protective effect of IT-066 (3 mg/kg, SC) or NOR3 (0.1 mg/kg, SC). Pretreatment with indomethacin (5 mg/kg, SC) markedly reduced the protective effect of IT-066 (3 mg/kg, PO) or NOR3 (0.1 mg/kg, SC). 5. These results suggest that endogenous NO and PGs may be implicated in the gastric mucosal protection induced by IT-066 and that the endogenous PGs may contribute to the protective effect of NO.

Animals↗
PubMed1998

Potentiation by DL-alpha-aminopimelate of the inhibitory action of a novel mGluR agonist (L-F2CCG-I) on monosynaptic excitation in the rat spinal cord.

1. Neuropharmacological actions of all the possible stereoisomers of 3',3'-difluoro-2-(carboxycyclopropyl)glycine (3',3'-difluoro-CCG) were compared with those of the corresponding 2-(carboxycyclopropyl)glycine (CCG) isomers in the isolated spinal cord of newborn rats. (2S,1'S,2'S)- and (2S,1'R,2'S)-2-(2-carboxy-3,3-difluorocyclopropyl)glycine (L-F2CCG-I and L-F2CCG-IV) were the most potent in causing depolarization, their threshold concentrations being approximately 1 microM. 2. The depolarization evoked by L-F2CCG-I (30 microM) was depressed by (+)-alpha-methyl-4-carboxyphenylglycine (MCPG, 1 mM (n=4)) to 17+/-3% of the control: this depolarizing action was not decreased by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 100 microM), and only slightly decreased by high concentrations of D-2-amino-5-phosphonopentanoic acid (D-AP5, 100 microM), suggesting that L-F2CCG-I activates mainly metabotropic glutamate receptors. 3. L-F2CCG-I preferentially depressed the monosynaptic component of the spinal reflex approximately 3 times more effectively than (2S,1'S,2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I). The depressant action of L-F2CCG-I (0.2 microM-0.7 microM) on monosynaptic excitation was antagonized by (2S,1'S,2'S)-2-methyl-2-(carboxycyclopropyl)glycine (MCCG, 0.3 mM-1 mM) and (S)-2-amino-2-methyl-4-phosphonobutanoic acid (MAP4, 0.3 mM). 4. DL-alpha-aminopimelate (10 and 100 microM) selectively potentiated the depression of monosynaptic excitation caused by L-CCG-I (0.2 microM) and L-F2CCG-I (0.1 microM). The actions of (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV) (50 nM-0.2 microM), L-2-amino-4-phosphonobutanoic acid (L-AP4) (0.3-1 microM), (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD) (1-7 microM) and baclofen (0.1-0.7 microM) were unaffected by DL-alpha-aminopimelate. The threshold concentration for the potentiating actions of DL-alpha-aminopimelate was 3 microM. 5. The depolarization induced by quisqualate (3 microM, 10 s application) was increased to 115+/-2% and 137+/-5% of the control values during combined application of quisqualate with either 30 microM or 100 microM DL-alpha-aminopimelate, respectively. 6. Following the application and subsequent washout of L-F2CCG-I, DL-alpha-aminopimelate (3-100 microM) decreased the amplitude of the monosynaptic component of spinal reflexes in a concentration-dependent manner, indicating a 'priming' effect of L-F2CCG-I.

Amino Acids, Dicarboxylic↗
PubMed1998

Expression pattern of synucleins (non-Abeta component of Alzheimer's disease amyloid precursor protein/alpha-synuclein) during murine brain development.

The non-Abeta component of Alzheimer's disease amyloid precursor protein (NACP) is predominantly a neuron-specific presynaptic protein that may play a central role in neurodegeneration because NACP fragments are found in Alzheimer's disease amyloid and a mutation in the NACP gene is associated with familial Parkinson's disease. In addition, NACP may play an important role during synaptogenesis and CNS development. To understand better the patterns of NACP expression during development, we analyzed the levels of this protein as well as the levels of another synaptic protein (synaptophysin) by ribonuclease protection assay, western blotting, and immunocytochemistry in fetal, juvenile, and adult mouse brain. From embryonic day 12 to 15, there was a slight increase, which was then followed by a more dramatic increase at later time points. Immunocytochemical staining for NACP increases throughout these stages as well. Although NACP appeared early in CNS development, synaptophysin levels started to rise at a later stage. These findings support the contention that NACP might be important for CNS development. Furthermore, the cytosolic component of NACP precedes the particulate component in development, indicating that a redistribution of the protein to the membrane fraction may be important for events later in neuronal development and in synaptogenesis.

Alzheimer Disease↗
PubMed1998

The improved image of indocyanine green angiography in young healthy volunteers.

PURPOSE: The authors performed indocyanine green (ICG) angiography in healthy volunteers using a high resolution ICG video system to obtain baseline images for subsequent studies. METHODS: Ten eyes of 10 healthy, young volunteers were studied. Before ICG angiography, all eyes were examined ophthalmoscopically and biomicroscopically and found to be intact. Indocyanine green (50 mg) dissolved in 2 mL of distilled water was injected through the antecubital vein. Video ICG angiogram was recorded until 30 minutes after the dye injection. RESULTS: Although the choroidal dye filling varied among subjects, it always began in the macular area. In the 10 volunteers, initial dye filling had two patterns: flush (n = 2) and reticular (n = 8). Patchy dye-filling delay in the posterior fundus was a common finding (n = 9). Vertical filling delay running between the medial and nasal cilial arteries was observed in nine eyes. The choroidal circulation filled completely before the retinal circulation did. At 30 minutes after dye injection, interstitial tissue staining of the choroid and vascular silhouette resulting from dye washout was observed in all eyes. CONCLUSIONS: Arterioles and capillaries of the choroid were well delineated by ICG angiography, resulting in better understanding of the physiologic and pathologic conditions of the choroidal circulations and the chorioretina itself.

Adult↗