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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 451 records · Page 25Linked to original sources
PubMed1988

Interleukin-1 can inhibit interferon-beta synthesis and its antiviral action: comparison with tumor necrosis factor.

Earlier studies showed that both tumor necrosis factor (TNF) and interleukin-1 (IL1) can inhibit virus replication in cultured cells. However, in human FS-4 fibroblasts, in which recombinant human TNF protected cells from encephalomyocarditis (EMC) virus infection, recombinant human IL1 alpha and IL1 beta failed to induce antiviral protection. Moreover, both forms of IL1 inhibited the development of the TNF-induced antiviral state. To elucidate the mechanism of this inhibition, we examined the effect of IL1 on the synthesis of interferon-beta (IFN-beta), stimulated with polyinosinate.polycytidylate [poly(I).poly(C)]. When added 2 h or more before poly(I).poly(C), both forms of IL1 had a strong inhibitory effect on IFN-beta synthesis, as determined by antiviral assay of the IFN-beta protein or by quantitation of IFN-beta mRNA levels in Northern blot analysis. However, when IL1 was added simultaneously with poly(I).poly(C), or 2 h after poly(I).poly(C), IFN-beta synthesis was increased. The inhibitory action of IL1 on poly(I).poly(C)-induced IFN-beta synthesis was abolished in the presence of cycloheximide, suggesting that it is mediated indirectly by an IL1-induced product in the FS-4 cells. In addition to its ability to inhibit IFN-beta synthesis, IL1 also caused a partial reversal of the antiviral action of IFN-beta. In contrast to IL1, TNF did not inhibit IFN-beta synthesis, nor did it interfere with the antiviral action of IFN-beta. Simultaneous addition of TNF and poly(I).poly(C) to FS-4 cells enhanced IFN-beta synthesis. Under proper conditions TNF and IFN-beta showed an additive antiviral effect.

Blotting, Northern↗
PubMed1988

Disulfide bond interchange in Escherichia coli-derived recombinant human interferon-beta 1 under denaturing conditions.

Disulfide bond interchange has been pointed out as a considerable problem in preparing recombinant proteins from Escherichia coli cells. This has been reported in the system of reducing denaturation followed by a refolding process, where incorrectly folded molecules are sometimes produced. As the possibility of disulfide bond interchange may also arise in the cytoplasm of E. coli cells, the state of sulfhydryl groups of recombinant proteins obtained from a nonreducing and nondenaturing process should be examined. The state of sulfhydryl groups of E. coli-derived recombinant human interferon-beta 1, which had been purified under nonreducing and nondenaturing conditions, was examined by using the N-(7-dimethylamino-4-methylcoumarinyl)maleimide (DACM) labeling technique. Among the three cysteine residues in E. coli-derived human interferon-beta 1, the 17th cysteine was identified as being unpaired, as in the natural molecule. However, it was found that three isomers of the recombinant protein could be formed when the protein was denatured with 6 M guanidine hydrochloride. These three isomers were identified as having unpaired cysteine residues at positions 17, 31, and 141, respectively. These results indicate that disulfide bond interchange occurs in E. coli-derived recombinant human interferon-beta 1 under denaturing conditions in spite of the absence of a reducing agent.

Disulfides↗
PubMed1988

Structural characterization of recombinant human interferon-gammas derived from two different mammalian cells.

Recombinant human interferon-gammas (rHuIFN-gamma s) were obtained from two different mammalian cells (mouse C127 cells and Chinese hamster ovary, CHO, cells) cultured in a microcarrier culture system. Both rHuIFN-gamma s were purified using sequential chromatographies for their comparison of structural properties. The peptide maps of HuIFN-gamma s digested with V8 protease and Western blot analysis demonstrated that C127 cells yielded mainly about 25kDa component and CHO cells produced about 25kDa and about 20kDa components. By the identification of glycosylated peptides, it was suggested that 20kDa and 25kDa components are glycosylated at one and at two sites, respectively. C-terminal amino acid sequence analysis indicated that both rHuIFN-gamma s consisted of at least six different species lacking 2 to 16 amino acid residues from C-terminus, so that C-termini of both rHuIFN-gamma s were slightly different from each other. Amino acid sequence and composition analyses of N-terminal peptides demonstrated that N-termini of both rHuIFN-gamma s were blocked and were supposed to be identical with that of natural HuIFN-gamma. These results suggested that different molecular heterogeneities of rHuIFN-gamma s resulted from the difference of post-translational modifications of host cells.

Amino Acid Sequence↗
PubMed1988

[Work-physiological assessment of eye-tracking task].

Mental work-load has increased with technical innovation, while manual work-load has decreased. As a result, eye fatigue has become one of the complaints in the modern working environment. Heretofore, the evaluation of visual work-load was based mainly on observation of the refractive power and accommodative function of the eyes. The purpose of this study is to assess, through observation of eye movement, the work-load created by eye-tracking tasks. The subjects were required to track, only by eye movement, a target oscillating between a distance of 35 cm in the horizontal or vertical direction for seven minutes. Mispursuit of the target, blinking and heart rate were recorded during the period of the experiment. The subjects were given eye-tracking tasks under nine conditions comprising angles 20 degrees, 40 degrees and 60 degrees in the respective moving widths and 0.1 Hz, 0.3 Hz and 0.5 Hz in the moving frequency of the target. Four healthy male volunteers participated in the eye-tracking experiments involving the horizontally moving target and five healthy male volunteers participated in those involving the vertically moving target. The task load condition of visual angle of 20 degrees with target frequency of 0.1 Hz was employed as standard. The relative velocity of the target and the velocity of eye movement were obtained using various combinations of visual angles and target frequencies. The following results were obtained: 1) The frequency of mispursuits increased significantly with the increase of relative target velocity. The degree of increase of mispursuit was especially remarkable at relative target velocities exceeding 1.0 Hz or at eye movement velocities exceeding 40 degrees/s.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The first epidemic of acute hemorrhagic conjunctivitis due to a coxsackievirus A24 variant in Okinawa, Japan, in 1985-1986.

Epidemics of acute hemorrhagic conjunctivitis due to a coxsackievirus A24 variant occurred in July-November, 1985 and August-October, 1986 in Okinawa Prefecture, Japan. This is the first report of an acute hemorrhagic conjunctivitis epidemic due to a coxsackievirus A24 variant in Japan The epidemic involved most islands of the prefecture. The prefectural surveillance center was notified of 9,952 cases in 1985 and 6,096 cases in 1986 from three sentinel eye clinics. The neutralizing antibody-positive rate against the coxsackievirus A24 variant of the serum samples collected before and immediately after the 1985 epidemic rose from 1.0% to 8.5%. The coxsackievirus A24 variant was isolated from 48 out of 68 conjunctival swabs collected during the epidemics. The isolates were indistinguishable antigenically in the plaque reduction test from the prototype strain, EH24/70, but had a markedly distinct oligonucleotide pattern.

Adolescent↗
PubMed1988

[The annual change in cases of early gastric cancer].

From 1963 to 1985, 1038 cases of early gastric cancer were treated at Fukui Prefecture Hospital. From a study that was undertaken, the incidence of early gastric cancer in cases of a resected gastric cancer was found to have increased. The age distribution and the sex ratio of early gastric cancer patients had not changed annually, though early gastric cancers that were detected by a mass survey or comprehensive physical examinations had increased. Macroscopically, early gastric cancers of the elevated type decreased while those of the depressed type increased. With regard to size, lesions smaller than 1.0 cm have increased during the past 5 years. Histologically, well-differentiated tubular adenocarcinomas have increased annually. The grade of intestinal metaplasia in the stomach has not changed.

Adenocarcinoma↗
PubMed1988

A case of hepatocellular carcinoma with tumor thrombi in the epiploic vein.

A case of hepatocellular carcinoma (HCC) with tumor thrombi in the vein in the major omentum is reported. A 54-year-old man underwent a second operation for recurrent HCC. Intraoperative ultrasonography revealed a tumor thrombus in the vein of the adhering omentum. Part of the antero-inferior area of the liver adjacent to the tumor was resected with the major omentum. Since it is characteristic of HCC often to form tumor thrombi in the veins, it is not surprising that the tumor budded into the epiploic vein. This is apparently the first report of tumor thrombi of HCC in the epiploic vein.

Carcinoma, Hepatocellular↗
PubMed1988

[A new technic of hepatectomy using peroperative echography and intraparenchymatous guide needles. The geometer technic].

A new technique of hepatectomy is described, using intra operative ultrasound and dental cleaner needle. The needle is inserted in the liver under ultrasonographic guidance, in order to mark the vessel which feed the tumor. Then the trans-section of the liver begins near the needle and the contact of its hip allows an elective ligation of the vessel. Thus the hepatectomy is performed safely along the ischaemic line of the subsegment bearing the tumor. The needle have been also used to mark the adjacent segmental portal vein and the hepatic vein which have to be secured during the operation. We have done 12 hepatectomies in cirrhotic patients with this technic without any complication.

Aged↗
PubMed1988

[Experimental study of single and combined coaxial exposure by high-peaked pulse wave CO2 and Nd:YAG laser on the brain: effect on the brain microvasculature in the subacute stage].

The effect of single or combined coaxial exposure by Nd: YAG and CO2 (pulse wave) laser on the brain at the subacute stage was examined in experimental animals. Soft X-ray microangiography and histological examination of the brain were performed 48 hours after laser exposure. The lasers in this study were pulse wave form CO2 of 2, 4 and 8 watts and YAG lasers of 10, 20 and 40 watts, employed separately or simultaneously using 130 YZ of Nihon Infrared Industries Company. Japanese white rabbits were anesthetized with pentobarbital. Bilateral fronto-parietal craniectomy were made, and the dura was removed. After intravenous injection of Evans blue, the lasers were employed to the cerebral cortex using a micromanipulator attached to the operation microscope. The spot size was 0.7 mm in diameter for CO2 laser and 1.2 mm for Nd: YAG laser. Forty-eight hours after exposure, microangiography was performed and brains were prepared for the histological examination. Histological examination and microangiogram of the brain after CO2 laser exposure revealed semilunar avascular area in the edematous layer surrounded with dilated vessels. Histological examination and microangiogram of the brain after Nd: YAG laser exposure revealed broad avascular or oligovascular zones in the surrounding edematous tissue, in which the surviving vessels were narrowed. Edematous zones were also shown in the subcortical portion. The histological examination and microangiogram after combined coaxial exposure of CO2 and Nd: YAG lasers revealed triangular avascular or oligovascular zones in the edematous tissue, in which the surviving vessels were narrowed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[A case of preoperative esophageal cancer developing lobar pneumonia due to MRSA infection of the catheter].

The 65-year-old male patient of esophageal cancer before operation suffered from lobar pneumonia. Bacteriological examination identified MRSA in his sputum and catheter tip. None of the cefem type antibiotics were effective, but CLDM and MINO were so much effective against that. We studied 47 cases of esophageal cancer which received operation last year. In many bacteria which were identified in the sputum and pus, MRSA occupied 30% as well as Pseud. aeruginosa. In the preoperative period enteral nutrition (ED) may be acceptable, if possible, as nutritional support alternative to TPN.

Aged↗