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Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 1,009 records · Page 56Linked to original sources
PubMed1986

Local and overall conformations of DNA double helices with the A - T base pairs.

Raman spectra have been observed of two different poly[d(A-T)].poly[d(A-T)] fibers, whose X-ray diffractions were confirmed to be purely of A and B forms. A number of spectral differences were found between the A and B forms of this DNA duplex, and they were ascribed to local conformational differences in the adenosine, thymidine and phosphodiester portions. The ascription was made on the basis of a separate series of Raman examinations on six crystals involving adenosine or thymidine, and fifteen other nucleotide crystals, whose structures are all known by previous crystallographic works. By taking these structure-spectrum correlations thus obtained into account, a Raman spectroscopic investigation was made of a few double-helical DNAs in aqueous solutions. It has been concluded that both poly[d(A-T)].poly[d(A-T)] and poly(dA).poly(dT) have a C2'endo-anti adenosine, C2'endo-anti thymidine, a b-type mainchain (beta = 160 +/- 15 degrees, gamma = 45 +/- 15 degrees, delta = 140 +/- 10 degrees) and an a2-type mainchain (beta = 210 +/- 10 degrees, gamma = 45 +/- 15 degrees, delta = 140 +/- 10 degrees) not only in low-salt medium but also in 6.6 M CsF solutions, where beta, gamma and delta are the torsion angles around O5'-C5', C5'-C4' and C4'-C3' axes, respectively. Poly(rA).poly(dT), on the other hand, was considered to have a heteronomous duplex structure, in which the poly(rA) strand has a C3'endo-anti adenosine and a1-type mainchain (beta = 175 +/- 25 degrees, gamma = 45 +/- 15 degrees, delta = 80 +/- 10 degrees) whereas the poly(dT) strand has a C2'endo-anti thymidine and b-type mainchain.

Adenosine↗
PubMed1986

Functional and molecular analysis of three distinct HLA-DR4 beta-chains responsible for the MLR between HLA-Dw4, Dw15, and DKT2.

Differences in structure and function of HLA-class II molecules between HLA-DR4-related HLA-D specificities HLA-Dw4, Dw15, and DKT2 were investigated. Anti-HLA-DR framework monoclonal antibody HU-4 completely inhibited the one-way mixed lymphocyte reaction (MLR) between these specificities. HU-4 precipitated a monomorphic alpha-chain and a polymorphic beta-chain of human class II molecules from each B lymphoblastoid cell line (BLCL) homozygous for these three HLA-D specificities. We established IL 2-dependent T cell lines specific for streptococcal cell wall (SCW) antigen from peripheral blood lymphocytes (PBL) from four DR4-positive donors: an HLA-Dw4/DKT2 heterozygote, an HLA-Dw4/Dw12 heterozygote, an HLA-DKT2/D-blank heterozygote, and an HLA-Dw15/D-blank heterozygote. These T cell lines showed a proliferative response to SCW antigen in the presence of autologous or allogeneic antigen-presenting cells (APC) when T cell donors and APC donors shared at least one of the HLA-D specificities. This cooperation between the T cell line and APC was completely blocked by HU-4. We conclude from these data that the T cells could distinguish three distinct DR4 molecules expressed on APC of HLA-Dw4, Dw15, and DKT2 as restriction molecules at the presentation of SCW antigen.

Antibodies, Monoclonal↗
PubMed1986

Coordination structures and reactivities of compound II in iron and manganese horseradish peroxidases. A resonance Raman study.

Resonance Raman investigations on compound II of native, diacetyldeuteroheme-, and manganese-substituted horseradish peroxidase (isozyme C) revealed that the metal-oxygen linkage in the compound differed from one another in its bond strength and/or structure. Fe(IV) = O stretching frequency for compound II of native enzyme was pH sensitive, giving the Raman line at 772 and 789 cm-1 at pH 7 and 10, respectively. The results confirmed the presence of a hydrogen bond between the oxo-ligand and a nearby amino acid residue (Sitter, A. J., Reczek, C. M., and Terner, J. (1985) J. Biol. Chem. 260, 7515-7522). The Fe(IV) = O stretch for compound II of diacetylheme-enzyme was located at 781 cm-1 at pH 7 which was 9 cm-1 higher than that of native enzyme compound II. At pH 10, however, the Fe(IV) = O stretch was found at 790 cm-1, essentially the same frequency as that of native enzyme compound II. The pK value for the pH transition, 8.5, was also the same as that of native compound II. Unlike in native enzyme, D2O-H2O exchange did not cause a shift of the Fe(IV) = O frequency of diacetylheme-enzyme. Thus, the metal-oxygen bond at pH 7 was stronger in diacetylheme-enzyme due to a weaker hydrogen bonding to the oxo-ligand, while the Fe(IV) = O bond strength became essentially the same between both enzymes at alkaline pH upon disruption of the hydrogen bond. A much lower reactivity of the diacetylheme-enzyme compound II was accounted to be due to the weaker hydrogen bond. Compound II of manganese-substituted enzyme exhibited Mn(IV)-oxygen stretch about 630 cm-1, which was pH insensitive but down-shifted by 18 cm-1 upon the D2O-H2O exchange. The finding indicates that its structure is in Mn(IV)-OH, where the proton is exchangeable with a water proton. These results establish that the structure of native enzyme compound II is Fe(IV) = O but not Fe(IV)-OH.

Horseradish Peroxidase↗
PubMed1986

The structure of nucleosome core particles as revealed by difference Raman spectroscopy.

Raman spectra have been observed of nucleosome core particles (I) prepared from chicken erythrocyte chromatin, its isolated 146 bp DNA (II), and its isolated histone octamer (H2A+H2B+H3+H4)2 (III). By examining the difference Raman spectra, (I)-(II), (I)-(III), and (I)-(II)-(III), several pieces of information have been obtained on the conformation of the DNA moiety, the conformation of the histone moiety, and the DNA-histone interaction in the nucleosome core particles. In the nucleosome core particles, about 15 bp (A.T rich) portions of the whole 146 bp DNA are considered to take an A-form conformation. These are considered to correspond to its bent portions which appear at intervals of 10 bp.

Animals↗
PubMed1986

Salt induced B----A transition of poly(dG).poly(dC) and the stabilization of A form by its methylation.

Raman spectra of poly(dG).poly(dC) have been observed in aqueous solutions at various ionic strengths, [NaCl] = 0.03 to 4 M, and at different temperatures, 10 to 60 degrees C. At 30 degrees C, and at [NaCl] = 0.03 M, it was found to have a B-form (with O4'endo-anti guanosine and C2'endo-anti cytidine), whereas, at [NaCl] = 4 M, an A form (with C3'endo-anti guanosine and C3'endo-anti cytidine). At 30 degrees C and [NaCl] = 1 M, namely at an intermediate state, a fraction of this molecules was considered to have a "heteronomous A" form (with O4'endo-anti guanosine and C3' endo-anti cytidine). At 60 degrees C and [NaCl] = 1 M, it assumes the B form, and at 10 degrees C and [NaCl] = 1 M, the A form. Cytosine-5-methylation was found to cause a marked stabilization of the A form. Even at [NaCl] = 0.1 M (at 30 degrees C), a substantial portion of poly(dG).poly(dm5C) was found to have a heteronomous form, in which the dG atrand is in the B form and the dC an A form; it never assumes a complete B form.

Methylation↗
PubMed1986

Nucleotide sequence of rat preputial gland beta-glucuronidase cDNA and in vitro insertion of its encoded polypeptide into microsomal membranes.

We have selected the rat preputial gland beta-glucuronidase as a model protein to study the sorting of newly synthesized lysosomal hydrolases to the lysosome. The complete coding sequence of beta-glucuronidase messenger RNA was determined from the sequences of a group of overlapping cDNA clones isolated from preputial gland cDNA libraries. The beta-glucuronidase mRNA primary translation product contains 648 amino acids, including an amino-terminal signal sequence of 22 residues. The polypeptide has four potential sites for the addition of asparagine-linked core oligosaccharides. A 376-residue segment of beta-glucuronidase shows extensive homology (23% sequence identity) to a portion of Escherichia coli beta-galactosidase. This homology most likely reflects an evolutionary relationship between the bacterial and eukaryotic enzymes and the conservation of structural features necessary for the glycosidase activity of both proteins. Translation of mRNA synthesized in vitro by transcription of a cDNA containing the entire beta-glucuronidase coding region yielded a polypeptide that was immunoprecipitated with anti-beta-glucuronidase antiserum and had the same electrophoretic mobility as the primary translation product of natural beta-glucuronidase mRNA. In the presence of microsomal membranes, the in vitro-synthesized beta-glucuronidase underwent cotranslational incorporation into the microsomes, as indicated by removal of the signal sequence and the addition of several oligosaccharide chains. The beta-glucuronidase cDNA will provide a useful tool to study the mechanism of mannose phosphorylation and other aspects of the sorting of lysosomal enzymes to lysosomes.

Animals↗
PubMed1986

Attenuation by pentobarbital of free fatty acid and diacylglycerol liberation during global ischaemia in rat brain.

The effects of global ischaemia and pentobarbital upon lipid metabolism were studied in the rat brain. Brain ischaemia was evoked by rat decapitation. Pentobarbital (60 mg/kg) was administered i.p. for 15 min prior to decapitation. The removed brains were incubated for 1, 5, 15 or 30 min at 37 degrees C and then quickly frozen in liquid nitrogen. After extraction of lipids from the brains, neutral lipid and phospholipid compositions were analysed by thin-layer and gas-liquid chromatography. The results demonstrated that free fatty acids (FFAs), either unsaturated or saturated, rapidly accumulated in the brain during the early period of ischaemia but attenuated significantly with pentobarbital pretreatment. Pentobarbital repressed the accumulations of stearate and arachidonate, with little effect on palmitate and oleate liberation. Diacylglycerols (DG) also were produced in the ischaemic brain, and their acyl chain composition was similar to that of liberated FFAs. However, the increase of DG was inhibited by pentobarbital anaesthesia. In particular, pentobarbital attenuated the formation of DG enriched in arachidonate and stearate. The fatty acyl composition of DG resembled that of phosphatidylinositol. These observations suggest that pentobarbital somehow may alter phospholipase C activity and influence inositol phospholipid breakdown during ischaemia, and this effect would be a membrane stabilizing action of pentobarbital.

Animals↗
PubMed1986

Left renal vein hypertension in patients with left renal bleeding of unknown origin.

The pullback pressure from the left renal vein (LRV) to the inferior vena cava was studied in 16 patients with left renal bleeding of unknown origin (group A), 15 patients with hematuria of miscellaneous laterality (group B), and nine control subjects (group C). The mean pressure gradients were 5.0 +/- 2.0 mm Hg (mean +/- SD) in group A, 1.9 +/- 1.0 mm Hg in group B, and 1.1 +/- 0.9 mm Hg in group C. The mean pressure gradient of group A was significantly higher than that of groups B and C (P less than .001). From the results of control studies, we regarded pressure gradients greater than or equal to 3.0 mm Hg as indicative of LRV hypertension. With this criterion, 88% (14 of 16) of the patients in group A had LRV hypertension, which was considered a cause of hematuria. Analysis of the results of renal angiography in the 31 patients revealed that opacification of collateral pathways of the LRV was a significant angiographic finding in LRV hypertension.

Adolescent↗
PubMed1986

Changes of tissue blood flow in mice loaded with SART (repeated cold) stress or restraint and water immersion stress and the effect of administered neurotropin.

In order to explore the peripheral microcirculation and to obtain an outline of autonomic innervation in SART (specific alternation of rhythm in temperature)-stressed (repeated cold-stressed) animals, which are regarded as model animals for clinical vagotonic-type dysautonomia, peripheral tissue blood flow was determined in mice, using the hydrogen clearance method. SART-stressed mice showed a decrease in gastric blood flow, no change in hepatic blood flow and an increase in dermal blood flow. In the mice exposed to the restraint and water immersion stress (RWIS), a type of acute stress, in contrast with SART stress which is a subacute type, remarkable decreases were observed in gastric, hepatic and dermal blood flows. Changes of both gastric and dermal blood flow in SART-stressed mice were dose-dependently prevented and maintained within normal limits by the treatment with Neurotropin, a sedative analgesic which is an extract isolated from vaccinia virus-inoculated and inflamed skin of rabbits. In RWIS-loaded mice, Neurotropin exhibited a great preventive effect on changes of blood flow in the stomach, a slight effect in the liver, and no effect in the cutis. When mice were loaded with SART stress after left-cervical vagotomy, SART stress failed to elicit any decrease in gastric blood flow. In SART-stressed mice treated with 6-hydroxydopamine, gastric and dermal blood flows tended to show a further decrease and increase, respectively, over and above the changes caused by SART stress. From these results, it is suggested that SART-stressed mice may have decreased gastric parasympathetic tone, a decrease in sympathetic tone and also other anomalies such as increased tension of the sympathetic cholinergic vasodilator nerves in the cutis.

Animals↗
PubMed1986

Histopathological changes in transplanted mouse mammary carcinoma following hyperthermia with or without radiation.

The histopathological effects of hyperthermia with or without radiation were investigated in a transplanted mouse mammary carcinoma. Since the histopathological changes following hyperthermia differed greatly between the center and periphery of a tumor, we analyzed the changes in each area separately according to a semi-quantitative method developed by us. Three days after hyperthermia at 44 degrees for 45 min, undamaged tumor cells were found mostly in the tumor periphery adjacent to normal tissues. This phenomenon was observed when the entire tumor could be heated almost homogeneously. When a tumor was treated by heat alone, the thermal damage disappeared 7 days after treatment. On the other hand, treatment with hyperthermia plus radiation caused pronounced damage in the tumor center and tumor periphery 7 and 14 days after treatment. These combination effects depended on the radiation dose. The present findings demonstrate that combination of high doses of irradiation and hyperthermia is very effective for potentiating the thermal damage in the tumor periphery.

Animals↗
PubMed1986

[A clinical bacteriological efficacy study on a fosfomycin otic solution].

Fosfomycin (FOM) otic solution was administered to 587 patients with suppurative otitis media infections including 190 patients in the dose-establishment test, 126 patients in the open clinical trial and 271 patients in the double blind test. Various bacteria were detected in the 549 cases in which bacteriological investigation was possible. Main bacteria detected from the above cases were S. aureus (261 strains, 47.5%), P. aeruginosa (93 strains, 16.9%), coagulase negative Staphylococci (CNS) (89 strains, 16.2%), Providencia spp. (35 strains, 6.4%) and Proteus spp. (28 strains, 5.1%). Twenty-seven strains of anaerobic bacteria (4.9%) were also detected. The MIC of FOM, and the reference drug, chloramphenicol (CP), fradiomycin (FRM), cefmenoxime (CMX) and cephalexin (CEX), were determined up to a concentration of 800 micrograms/ml with inoculum sizes of 10(6) and 10(8) CFU/ml. About 30% of S. aureus was multi-drug resistant, including methicillin and cephems, but FOM showed excellent antibacterial activity against it. The FOM had superior antibacterial activity against P. aeruginosa to CP, FRM and CMX, and was also active against other bacteria. The antibacterial activity of FOM was inferior to other drugs against CNS, Enterobacter spp., P. putida and P. cepacia. The detection rate of these bacteria, however, was low and since their role as causative organisms is not well defined, the inferior activity of FOM has no effect on the bacteriological evaluation of FOM. Since the concentration in the tympanic cavity about 1 hour after the administration of 3% FOM solution was estimated to be 2,000 to 3,000 micrograms/ml, it could be presumed that bacteria inhibited by 800 micrograms/ml of FOM at an inoculum size of 10(8) CFU/ml would be eradicable. The low ototoxicity of FOM is likely due to its characteristic as an inhibitor of bacterial cell wall synthesis. From these results, 3% FOM otic solution may be considered as a remarkably useful topical preparation for the treatment of suppurative otitis media.

Administration, Topical↗
PubMed1986

HLA in Buerger's disease.

Recent studies have focused on the possible genetic factor(s) in the pathogenesis of Buerger's disease as well as in Takayasu's disease. We investigated HLA-A, B, C, DR, and DQ antigens in 59 patients with Buerger's disease to confirm statistically significant high frequencies of Aw24, Bw40, Bw54, Cw1, and DR2 antigens and a low frequency of DR9 and DRw52 as compared with those in 152 normal Japanese individuals. As the haplotpye Aw24-Bw54-Cw1-DR4 is known to be common among Japanese, a significantly high frequency of haplotype Bw54-DR2 found in cases of Buerger's disease, instead of that of Bw54-DR4, may suggest a possible cross-linkage occurrence in chromosome 6, which could prove to be an important causative phenomenon in the pathophysiology of Buerger's disease.

Disease Susceptibility↗