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Biomedical subjects

N Shirai

Publications and source records attributed to N Shirai.

At least 55 records · Page 3Linked to original sources
PubMed1999

H+/K+-adenosine triphosphatase mRNA in gastric fundic gland mucosa in patients infected with Helicobacter pylori.

BACKGROUND: How Helicobacter pylori infection affects gastric acid secretion has not been made clear. This study aimed to elucidate the effects of H. pylori infection on H+/K+-adenosine triphosphatase (ATPase) mRNA in gastric fundic gland mucosa. METHODS: Twenty patients with chronic gastritis and H. pylori infection were treated with lansoprazole and antibiotics. Before and 1 month after treatment gastroduodenoscopy was performed, and changes in the amount of H+/K+-ATPase mRNA in the fundic gland mucosa, gastric juice pH, and serum gastrin levels were determined. RESULTS: The amount of H+/ K+-ATPase mRNA in the fundic gland mucosa was increased in patients with eradication of H. pylori, in whom significant decreases in gastric juice pH and serum gastrin levels were observed. No significant changes were observed in patients without eradication of H. pylori. CONCLUSIONS: These results suggest that one of the mechanisms by which H. pylori infection suppresses acid secretion is by the inhibition of proton pump synthesis in parietal cells.

DNA Primers↗
PubMed1999

Relation between interleukin-1beta messenger RNA in gastric fundic mucosa and gastric juice pH in patients infected with Helicobacter pylori.

The effects of Helicobacter pylori infection on gastric acid secretion has not been clarified. The aim of this study was to elucidate the effects of H. pylori infection on gastric juice pH in relation to gene expression of interleukin-1beta (IL-1beta), which is reported to inhibit gastric acid secretion. Gastric juice pH and serum gastrin levels were measured in patients with peptic ulcer disease. The amount of IL-1beta mRNA in gastric fundic gland mucosa was also measured by a competitive reverse transcription-polymerase chain reaction method. These parameters were determined before and after treatment with lansoprazole and amoxicillin. Before treatment a significant positive relation was observed between the amount of IL-1beta mRNA in gastric fundic gland mucosa and gastric juice pH. After treatment significant decreases in the amount of IL-1beta mRNA, gastric juice pH, and serum gastrin levels were observed in patients with eradication of H. pylori, whereas no significant changes were observed in patients without eradication. These results suggest that H. pylori infection induces IL-1beta and suppresses acid secretion, resulting in increases in gastric juice pH and serum gastrin levels. Eradication of H. pylori decreases IL-1beta induction, resulting in an increase in gastric juice acidity and normalization of serum gastrin levels.

Base Sequence↗
PubMed1998

A de novo missense mutation of human cardiac Na+ channel exhibiting novel molecular mechanisms of long QT syndrome.

Mutations in a human cardiac Na+ channel gene (SCN5A) are responsible for chromosome 3-linked congenital long QT syndrome (LQT3). Here we characterized a de novo missense mutation (R1623Q, S4 segment of domain 4) identified in an infant Japanese girl with a severe form of LQT3. When expressed in oocytes, mutant Na+ channels exhibited only minor abnormalities in channel activation, but in contrast to three previously characterized LQT3 mutations, had significantly delayed macroscopic inactivation. Single channel analysis revealed that R1623Q channels have significantly prolonged open times with bursting behavior, suggesting a novel mechanism of pathophysiology in Na+ channel-linked long QT syndrome.

Animals↗
PubMed1998

Reliability of internal jugular vein in oral microvascular reconstruction.

OBJECTIVE: The purpose of this study was to review the reliability of the internal jugular vein when used as a recipient vein in oral microvascular reconstruction. STUDY DESIGN: A retrospective study was done of 36 consecutive cases in which microvascular reconstruction was accomplished with a free flap using the internal jugular vein in an end-to-side fashion. The postoperative patency of 25 internal jugular veins used as recipient veins was examined by postcontrast computed tomography scanning. RESULTS: The overall flap success rate was 97%. Venous thromboses occurred in 2 cases. A common venous thrombosis occurred in one case, but the flap survived after re-anastomosis. In another case, internal jugular vein thrombosis occurred at 5 days of anastomosis, and the flap could not be salvaged by exploratory surgery. All other cases were completely uneventful. All internal jugular veins assessed on postcontrast computed tomography scans were patent at 51 to 107 days after surgery (mean, 89 days). CONCLUSION: Internal jugular vein, if available, is reliable when used as a recipient vein in oral microvascular reconstruction. However, it is not necessarily flawless.

Adult↗
PubMed1998

Safety assessment of genetically engineered food: detection and monitoring of glyphosate-tolerant soybeans.

A detection technique for the genetically engineered food, glyphosate-tolerant soybean (GTS), was designed. Commercial soybeans imported from North America were cultured in pots and genomic DNA was isolated from their leaves. To detect the genes, promoter and terminator, involved in the expression of glyphosate tolerance, PCR was done using the genomic DNA and chemically synthesized primers specific to the genes. DNAs with predicted sizes were amplified and confirmed by DNA sequencing to be the genes responsible for the expression of glyphosate tolerance. Glyphosate-tolerant soybeans were found to form approximately 1.1% of the commercial soybeans, when commercially available soybeans were cultivated and number of soybeans resistant to glyphosate was found. This level is somewhat lower than an estimated value announced officially on the basis of the cultivation area of the glyphosate-tolerant soybeans.

Base Sequence↗
PubMed1997

Temperature control for kinetic refolding of heat-denatured ovalbumin.

The folding of heat-denatured ovalbumin, a non-inhibitory serpin with a molecular size of 45 kDa, was examined. Ovalbumin was heat-denatured at 80 degrees C under nonreducing conditions at pH 7.5 and then cooled either slowly or rapidly. Slow cooling allowed the heat-denatured ovalbumin to refold to its native structure with subsequent resistance to digestion by trypsin. Upon rapid cooling, by contrast, the heat-denatured molecules assumed the metastable non-native conformations that were susceptible to trypsin. The non-native species were marginally stable for several days at a low temperature, but the molecules were transformed slowly into the native conformation. Considering data from size-exclusion chromatography and from analyses of CD, intrinsic tryptophan fluorescence, and adsorption of the dye 1-anilinonaphthalene-8-sulfonate, we postulated that the non-native species that accumulated upon rapid cooling were compact but structureless globules with disordered side chains collectively as a folding intermediate. Temperature-jumped CD experiments revealed biphasic kinetics for the refolding process of heat-denatured ovalbumin, with the features of increasing and subsequently decreasing amplitude of the rapid and the slow phases, respectively, with the decrease in folding temperature. The temperature dependence of the refolding kinetics indicated that the yield of renaturation was maximal at about 55 degrees C. These findings suggested the kinetic partitioning of heat-denatured ovalbumin between alternative fates, slow renaturation to the native state and rapid collapse to the metastable intermediate state. Analysis of disulfide pairing revealed the formation of a scrambled form with non-native disulfide interactions in both the heat-denatured state and the intermediate state that accumulated upon rapid cooling, suggesting that non-native disulfide pairing is responsible for the kinetic barriers that retard the correct folding of ovalbumin.

Animals↗
PubMed1997

Linear polymerization caused by the defective folding of a non-inhibitory serpin ovalbumin.

Polymerization caused by defective folding of heat-denatured ovalbumin was examined. A compactly misfolded ovalbumin that was produced by cooling heat-denatured protein rapidly tended to aggregate in the presence of salt. Two different forms of aggregates were observed as the concentration of salt was varied: a linear polymer at a physiological concentration and a massive agglomerate at a higher concentration. Salt-induced polymerization depended on the species of anion and the order of effectiveness followed the lyotropic series of Hofmeister. Defective folding of heat-denatured ovalbumin induced the exposure of cysteine residues in sequences located in the interior of the native protein. The misfolded ovalbumin, but not the native protein, bound to bovine BiP and stimulated its ATPase activity with the K(m) of 64 microM and the V(max) of 0.5 nmol/min per milligram. Measurement of surface plasmon resonance revealed that only the misfolded ovalbumin was recognized with the K(d) of 4.12 X 10(-8) M by the Fab fragment of a monoclonal antibody raised against hen ovalbumin, and its epitope was determined to be a hydrophobic segment in the beta-strand of central sheet A. Transmission electron microscopy showed that the linear polymerization was inhibited by the addition of bovine BiP and the Fab fragment. These results demonstrated that the compactly misfolded ovalbumin polymerized through hydrophobic interaction occurring among the areas exposed as a result of defective folding of the heat-denatured protein. Exposure of the region of, or adjacent to, the central beta-sheet A was required for axial contact among the misfolded molecules, suggesting that this process may be explained by reference to the mechanism proposed for loop-sheet polymerization in the Z type variant of a serpin alpha1-antitrypsin.

Animals↗
PubMed1996

Full-thickness reconstruction of cheek defect involving oral commissure with forearm tendinocutaneous flap.

An 82-year-old man underwent full-thickness reconstruction of the cheek for a defect of the oral commissure resulting from a T3N1M0 squamous cell carcinoma. He had previously had both radiotherapy and chemotherapy. A tendinocutaneous flap from the forearm incorporating palmaris longus was used for static reconstruction. The vermilion was then reconstructed with rotation flaps from the contralateral vermilion. Oral function was restored, and he had no problems with drooling or speech.

Aged↗
PubMed1995

Intraoral reconstruction with innervated forearm flap: a comparison of sensibility and reinnervation in innervated versus noninnervated forearm flap.

OBJECTIVE: To evaluate the cutaneous sensibility and sensory reinnervation in patients who underwent intraoral reconstruction with an innervated or noninnervated forearm flap. STUDY DESIGN: Results of the use of innervated forearm flaps in oral reconstruction was compared with the use of noninnervated flaps. The evaluation of sensibility and reinnervation comprised clinical sensibility tests and immunohistochemical investigation of postoperative biopsy specimens against S-100 and neurofilament. RESULTS: The innervated flaps (4 patients) provided earlier and qualitatively better recovery of sensation than the noninnervated flaps (9 patients). Immunohistochemical investigation revealed the existence of a larger number of regularly arranged sensory nerve fibers in the cutaneous tissue of the innervated flaps than in the noninnervated flaps. Examination with an electron microscope found the structure of these nerve fibers to be well preserved in the innervated flaps, whereas nerve fibers in the noninnervated flaps were degenerative. CONCLUSION: These findings suggest (1) that the innervated flaps are superior to the noninnervated flaps not only for the repair of defects but also for the restoration of function and (2) that the innervated flaps contribute to the improvement of the quality of life for patients.

Adult↗
PubMed1995

Transovarian transmission of a foreign gene in the silkworm, Bombyx mori, by Autographa californica nuclear polyhedrosis virus.

We introduced a firefly luciferase gene, expressed under control of Drosophila heat shock protein gene promoter, into Autographa californica nuclear polyhedrosis virus (AcNPV). When the 5th instar larvae of the silkworm, Bombyx mori, were inoculated with the recombinant virus, luciferase activities were detected in the virus-infected larvae and pupae, and in the newly hatched larvae of the next generation. PCR amplification and Southern blot hybridization analysis demonstrated that the luciferase gene was transmitted through at least the F2 generation. In addition, the V-cathepsin gene, encoding a cysteine protease of AcNPV, was also detected in the DNA of all individuals of the F2 generation. These results show that AcNPV can be utilized as vector for the transovarian transmission of foreign genes in the silkworm.

Animals↗
PubMed1994

[New development of ammonium ylide chemistry].

Benzylammonium N-alkylides were generated by reaction of N-[1-(trimethylsilyl)alkyl]benzylammonium salts with cesium fluoride in DMF or HMPA, and their rearrangement products were investigated. [2,3]Sigmatropic rearrangement of the ylides initially occurred to give isotoluene derivatives and then they were transformed into Sommelet-Hauser rearrangement products and/or Stevens products. The isotoluenes having bicyclic structures were stable at room temperature and aromatized with the aid of a base. The relationship between the configuration of cyclic ammonium ylides and the rearrangement paths is described.

Benzalkonium Compounds↗
PubMed1993

Symmetrical lipomatosis of the tongue presenting as macroglossia. Report of two cases.

Symmetrical lipomatosis in the oral cavity is extremely rare. Two cases of symmetrical lipomatosis presenting as macroglossia are presented. Glossectomy was performed in order to reduce the size of the tongue and for diagnosis. Because of their multiplicity, non-encapsulation and invasiveness, the lesions were diagnosed histopathologically as symmetrical lipomatosis.

Aged↗
PubMed1992

Foreign gene expression by a baculovirus vector with an expanded host range.

A nuclear polyhedrosis virus (NPV) (Baculoviridae)-based gene expression system was improved by DNA recombination. The BmN cell line established from Bombyx mori and the Sf21 cell line established from Spodoptera frugiperda are non-permissive for Autographa californica multicapsid NPV (AcMNPV) and B. mori NPV (BmNPV) replication, respectively. After cotransfection of AcMNPV DNA and BamHI-digested BmNPV DNA into Sf21 cells, progeny viruses were isolated by plaque purification on BmN cell monolayers and the host specificity of one viral isolate was analysed. The virus had a wider host range, and replicated and produced polyhedra in Sf21 cells, BmN cells and larvae of the silkworm, B. mori. DNA restriction endonuclease analysis showed that the isolate was a hybrid of AcMNPV and BmNPV. Using the AcMNPV transfer vector pAcYM1 a portion of the polyhedrin gene of the hybrid virus was replaced with the coding region of the firefly luciferase gene, producing a recombinant virus. The latter expressed firefly luciferase in both cell lines and in silkworm larvae under the control of the polyhedrin promoter.

Baculoviridae↗
PubMed1988

Effects of intermittent pneumatic leg compression for prevention of postoperative deep venous thrombosis with special reference to fibrinolytic activity.

The mechanism of intermittent pneumatic leg compression for prevention of postoperative deep venous thrombosis was investigated. The incidence of postoperative deep venous thrombosis was studied using iodine-125 fibrinogen in 64 patients with malignant disease who had intermittent pneumatic leg compression for 48 hours postoperatively. Changes in euglobulin lysis time and B beta 15-42 peptide were investigated before and after operation in 16 patients with benign disease, in 27 patients with malignant disease who did not have postoperative intermittent pneumatic leg compression, and in another 29 patients with malignant disease who had postoperative intermittent pneumatic leg compression. The overall incidence of deep venous thrombosis was 6.25 percent. A prolongation of euglobulin lysis time was found postoperatively in all three groups, which was significant in malignant disease groups, although less significant in the group with intermittent pneumatic leg compression when compared with the benign disease group. Preoperatively, a significant increase in B beta 15-42 peptide was found in patients with malignant disease when compared with patients with benign disease. Postoperatively, the B beta 15-42 level increased in the same pattern in all groups and no significant differences in the levels were found among them. A significant shortening of euglobulin lysis time by intermittent pneumatic leg compression, in addition to its hemodynamic effects, is considered an important factor in the prevention of postoperative deep venous thrombosis.

Female↗
PubMed1986

Bacterial and mammalian cell mutagenicity of four optically active bay-region 3,4-diol-1,2-epoxides and other derivatives of the nitrogen heterocycle dibenz[c,h]acridine.

The mutagenic activities of the enantiomers of the diastereomeric pair of bay-region 3,4-diol-1,2-epoxides of the nitrogen heterocycle, dibenz[c,h]acridine, have been evaluated in histidine-dependent strains of Salmonella typhimurium and in an 8-azaguanine-sensitive line of Chinese hamster cells. In strains TA 98 and TA 100 of S. typhimurium the pair of enantiomers with [1R,2S,3S,4R] and [1S,2R,3R,4S] absolute configuration and the benzylic hydroxyl group trans to the epoxide oxygen are 2 to 4 times more mutagenic than the [1S,2R,3S,4R] and [1R,2S,3R,4S] isomers in which the benzylic hydroxyl and epoxide oxygen are cis. In both strains of bacteria there is very little difference in mutagenic activity between the enantiomers of each diastereomer. In contrast to these results in bacteria, the bay-region 3,4-diol-1,2-epoxide isomer with [1R,2S,3S,4R] absolute configuration is 5 to 7 times more mutagenic to Chinese hamster V79 cells than are the other 3 isomers. The enantiomeric pair of bay-region tetrahydro-1,2-epoxides of dibenz[c,h]acridine are at least 7 times more mutagenic than the diol-epoxides in the Salmonella assay, and no difference in mutagenic activity is observed between enantiomers. In the Chinese hamster V79 cell system, however, the tetrahydro-1,2-epoxide with [1R,2S] absolute configuration is 2- to 3-fold more mutagenic than its enantiomer with [1S,2R] absolute configuration. Homogeneous rat liver epoxide hydrolase does not catalyze the hydration of the diol-epoxide isomers to nonmutagenic products, although the tetrahydroepoxides, especially the tetrahydro-3,4-epoxide, are metabolized by the enzyme. Results of metabolic activation experiments with the bacterial mutagenesis system and microsomes from Aroclor 1254-treated rats are consistent with the mutagenicity data described above and support the concept that dibenz[c,h]acridine is metabolically activated to a bay-region diol-epoxide. Notably: (a) 3,4-dihydrodibenz[c,h]acridine, the expected precursor of a bay-region tetrahydroepoxide, is metabolized to a potent mutagen; (b) racemic dibenz[c,h]acridine 3,4-dihydrodiol is metabolized to products which are several-fold more mutagenic than are products of the metabolism of dibenz[c,h]acridine or its 1,2- or 5,6-dihydrodiols; and (c) the tetrahydro-3,4-diol, which lacks the isolated bay-region double bond, is not metabolically activated to a bacterial mutagen.

Acridines↗