Biomedical subjects
Publications and source records attributed to Ryoji Tanaka.
To explore the anion recognition ability of silanol hydroxy groups, a silanediol-based receptor 1 was prepared. Spectroscopic studies and X-ray crystallography revealed that the receptor exhibits the characteristic recognition of anions via two hydrogen bonds in chloroform.
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The dengue virus is currently the most important flavivirus causing human diseases in the tropical and subtropical regions of the world. The envelope protein domain III of dengue virus type 2 (D2EIII), which induces protective and neutralizing antibodies, was expressed as an N-terminal fusion to a hexa-histidine tag in Escherichia coli. The expression of recombinant D2EIII of 103 amino acids in the soluble form can be achieved using suitable host strains, such as Origami, at a low induction temperature of 18 degrees C. The enhanced production of the soluble protein could be attributed to the thioredoxin reductase (trxB) and glutathione reductase (gor) double mutations in the Origami genome. The soluble and refolded D2EIII proteins were recognized by different antibodies including human patient antiserum. The immunization of rats with soluble D2EIII protein elicited the production of antibodies that could recognize the D2EIII protein in the D2EIII precursor protein and in C-terminal truncated dengue envelope protein type 1-4. Thus, this protein production system is suitable for the production of authentic recombinant dengue proteins that may be used in the diagnosis of the dengue virus infection or in vaccine development.
BACKGROUND: Although a variety of papers demonstrated inhibited hepatocarcinogenesis with interferon (IFN) therapy for chronic hepatitis C, a small number of hepatocellular carcinomas (HCCs) were still observed even in sustained virologic responders. AIMS: To clarify factors affecting the development of HCC, we analyzed the frequency of HCC in sustained virologic responders over a long-term observation period. METHODS: Seven hundred and ninety-two out of the 2623 IFN-treated hepatitis C patients who had undergone liver biopsy showed sustained virologic response. Screening for development of HCC was performed periodically during an average follow-up of 5.1 years. Fibrosis of the pretreatment liver biopsy sample was graded. Risk factors for HCC were analyzed by using Cox proportional hazards regression. RESULTS: Of 792 patients, 23 developed HCC. Univariate analysis showed that stage of hepatic fibrosis, age, and alcohol consumption were significantly associated with a risk of HCC (P<0.001). There was a significant difference in the cumulative incidence between patients stratified according to these variables (P<0.001). CONCLUSIONS: Pretreatment hepatic fibrosis score, age, and alcohol consumption may affect development of HCC even in sustained virologic responders. Thus, patients with these factors should be carefully followed even after eradication of the virus.
Novel (2S,4R)- and (2S,4S)-4-aminoproline residue-containing analogs of the cyclic decapeptide antibiotic gramicidin S were synthesized, which exhibited marked permeabilizing activity on the outer membrane of gram-negative bacteria.
The aim of this article is to describe the results of our investigation on the chiral crystallization of anti-tricyclic ladder polysilane, anti-dodecaisopropyltricyclo [4.2.0.0(2,5)] octasilane (1). In solid state, the silicon framework of 1 adopts twisted conformation in which the Si4 rings are puckered in the same direction. Crystallization of 1 afforded a large conglomerate crystal in high yield. X-ray crystallography revealed that the crystal consists of either right-handed (P) or left-handed (M) molecules. The ultraviolet and circular dichroism spectra of the chiral crystals of 1 reveal two absorption bands in the 400-250 nm region.