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Biomedical subjects

N Kasai

Publications and source records attributed to N Kasai.

At least 145 records · Page 8Linked to original sources
PubMed1986

Preliminary crystallographic study of a ribulose-1,5-bisphosphate carboxylase-oxygenase from Chromatium vinosum.

Crystals of a ribulose-1,5-bisphosphate carboxylase-oxygenase from Chromatium vinosum were obtained with the hanging-drop vapor diffusion technique, using polyethylene glycol 4000 as precipitant. The crystal belongs to the cubic system, space group I432, with unit cell dimension a = 245.9 A. An asymmetric unit includes one-quarter (L2S2, L: large subunit, S: small subunit) of a hexadecameric molecule (L8S8, 544,000 Mr), which is located on the crystallographic point symmetry 222 or 4. The crystal diffracts to at least 3.0 A resolution.

Chromatium↗
PubMed1986

Crystallization and preliminary X-ray diffraction study of ferrocytochrome c2 from Rhodopseudomonas viridis.

Crystals of ferrocytochrome c2 from a non-sulphur purple photosynthetic bacterium, Rhodopseudomonas viridis, have been grown from ammonium sulphate solution at pH 8.5 by the sitting-drop vapour-diffusion procedure. The crystals belong to the trigonal system, space group P3(1)21 (or its enantiomorph P3(2)21) with unit-cell dimensions of a = b = 75.8 A and c = 40.1 A, and diffract to at least 2.0 A resolution. Assuming that an asymmetric unit contains one protein molecule (approx. 12,300 Mr), the solvent content of the crystal is approximately 54.5% (v/v).

Crystallization↗
PubMed1986

Anti-glycolipid antibodies and their immune complexes in multiple sclerosis.

Antibody titers against myelin constituents in sera and CSF of patients with multiple sclerosis (MS) were examined by a solid-phase radioimmunoassay. Anti-GM4 and anti-galactocerebroside antibody titers were significantly elevated in the CSF of MS patients, but not anti-GM1 and anti-myelin basic protein antibodies. In sera of MS patients, the titers of antibodies against these myelin constituents were not elevated. Total IgG level was also significantly elevated in the CSF, but not in the sera of MS patients. Immune complexes from the CSF of MS patients were dissociated by acid-ultrafiltration and assayed for antibodies to GM4, GM1, and galactocerebroside. Anti-GM4 and antigalactocerebroside antibody titers were significantly enhanced after acid dissociation and ultrafiltration. These data suggest that antibodies of the IgG class against GM4 and galactocerebroside are present in CSF of MS patients, and a significant number of them exist as immune complexes with their corresponding glycolipid antigens.

Antibody Specificity↗
PubMed1986

Crystal structures of modified myoglobins. I. Heme orientation and structural changes around heme in myoglobins reconstituted with isopemptoheme, pemptoheme, 2-ethyldeuteroheme, and 4-ethyldeuteroheme.

The crystal structures of sperm whale metmyoglobins reconstituted with four modified hemes, isopemptoheme, pemptoheme, 2-ethyldeuteroheme, and 4-ethyldeuteroheme, have been determined and refined at 2.2 A resolution to R = 0.217, 0.218, 0.213, and 0.222, respectively. All the crystals of these myoglobins are isomorphous with that of native metmyoglobin. The structural changes of the modified myoglobin from the native myoglobin were examined on difference Fourier maps; the orientation of 4-ethyldeuteroheme in the heme pocket is such that the heme is rotated by 180 degrees about an axis through the alpha-gamma-meso carbons, whereas the orientations of the other three hemes are the same as that of the protoheme in the native myoglobin. The changes of the structures around the heme become greater in the order of isopemptoheme, 2-ethyldeuteroheme less than pemptoheme less than 4-ethyldeuteroheme. The magnitudes of the changes seem to be related to the oxygen affinities of these four reconstituted myoglobins.

Animals↗
PubMed1986

Crystal structures of modified myoglobins. II. Relation between oxygen affinity properties and structural changes around heme in myoglobins reconstituted with 2,4-diisopropyldeuteroheme, 2-isopropyl-4-vinyldeuteroheme, and 2-vinyl-4-isopropyldeuteroheme.

The crystal structures of sperm whale metmyoglobins reconstituted with three kinds of modified hemes, 2,4-diisopropyldeuteroheme, 2-isopropyl-4-vinyldeuteroheme, and 2-vinyl-4-isopropyldeuteroheme, have been determined and refined at 2.2 A resolution to R = 0.216, 0.219, and 0.195, respectively. All the crystals of these myoglobins are isomorphous with that of native metmyoglobin. The 2-vinyl-4-isopropyldeuteroheme was found to be in a reverse orientation, in which the heme plane is rotated by 180 degrees about an axis through the alpha-gamma-meso carbons, whereas the orientations of the other two hemes were the same as that of protoheme in native myoglobin. In the myoglobins with 2,4-diisopropyldeuteroheme and 2-vinyl-4-isopropyldeuteroheme, both of which have lower oxygen affinities than native myoglobin, the bulky isopropyl side chain pushes Phe 43 0.7 A toward His 64 (the distal histidine) in the former, and the whole E helix at most 1.5 A, including a 0.7 A shift of the His 64 imidazole ring, in the latter. The changes of the structures prevent His 64 from forming a hydrogen bond with the liganded oxygen molecule, so that these two modified myoglobins show low oxygen affinities. On the other hand, there is no such drastic displacement in myoglobin with 2-isopropyl-4-vinyldeuteroheme, which has a slightly higher oxygen affinity than native myoglobin.

Animals↗
PubMed1986

Barley leaf peroxidase: purification and characterization.

Peroxidase was prepared from extracts of barley leaves and separated into seven components, different in pI. The purification procedure comprised two parts. The first part was based on the fact that all the components had practically the same molecular weights. It consisted of fractionations with acetone and ammonium sulfate, ion-exchange chromatographies on CM-cellulose and DEAE-Sepharose CL-6B, and molecular-sieve chromatography on Ultrogel AcA44; the components were all purified together to near homogeneity on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, and the procedure resulted in 1,200-fold purification with a yield of 39%. The ion-exchange chromatographies were carried out under conditions such that the components would not be adsorbed. In the second part, the enzyme preparation was separated into the seven components by repeating isoelectric electrophoresis. Their isoelectric points (pI) were 6.3, 6.8, 7.4, 8.3, 8.5, 8.7, and 9.3. The components other than the pI 6.3 and 6.8 components were each purified to homogeneity in the electrophoresis. The seven components thus prepared were the same in molecular weight on SDS-gel electrophoresis (44,000) and showed absorption maxima at the same wave-lengths (403, 496, and 534 nm), RZ (A403/A275) ranging from 2.09 to 2.81. Their protoheme IX contents were 0.81-1.07 mol/mol, and their true sugar contents 15-26% (g/g). The amino acid compositions suggest that the five components described above are not real isoenzymes, but exhibit different pI values due to differences in glycosyl residue. The pI 9.3 component was crystallized in spite of its high sugar content.

Crystallization↗
PubMed1986

Synthetic Salmonella-type lipid A antigen with high serological specificity.

A synthetic compound (compound 516), beta(1-6)-linked D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated by (R)-3-hexadecanoyloxytetradecanoyl, (R)-3-hydroxytetradecanoyl, (R)-3-dodecanoyloxytetradecanoyl, and (R)-3-tetradecanoyloxytetradecanoyl groups at positions 2,3,2', and 3', respectively, exhibited in vitro antigenic reactivity of high specificity comparable to that of free lipid A from Salmonella minnesota R595. This was confirmed by an enzyme-linked immunosorbent assay and an enzyme-linked immunosorbent assay inhibition test with monoclonal and conventional antibodies. The results of comparative analysis performed with several synthetic lipid A analogs as well as three monosaccharide derivatives suggested that the complete structure involving both phosphate groups at the C-1 and C-4' positions and the 3-acyloxyacyl groups at the C-2, C-2', and C-3' positions of the glucosamine disaccharide are required for the expression of the serological specificity of Salmonella-type lipid A. This was deduced from the observations that compound 506, a synthetic Escherichia coli-type lipid A which has the same structure as that of compound 516, except that 3-hydroxytetradecanoyl group is substituted for an acyloxyacyl residue at the C-2 position, exhibited significantly reduced antigenic reactivity as compared with compound 516 and that the replacement by the hydrogen atom of the phosphoryl group at the C-1 position or by 3-hydroxytetradecanoyl or tetradecanoyl groups of acyl residues at the 2, 3, 2', and 3' positions of compound 516 results in a marked reduction of reactivity with monoclonal antibodies 5G and 36G. Similar results were obtained by assays with conventional rabbit antibodies, but the structural difference between compounds 516 and 506 could not be distinguished by these polyclonal antibodies. The results of cross-reactions among synthetic analogs with monoclonal antibodies 161M and 1-9M, which have been confirmed to exhibit different serological specificities from the 5G or 36G antibody, also suggested that the nature and linkage of fatty acyl residues as well as the backbone structure of lipid A play an important role in determining serological specificity of the lipid A molecule.

Antigens, Bacterial↗
PubMed1986

[Imaging diagnosis of head and neck cancer--diagnosis of laryngeal cancer, hypopharyngeal cancer and cancer of the cervical esophagus by CT x-ray].

Fifty-six patients with laryngeal cancer were examined. The rate of correct diagnosis of clinical staging was 64.3%. Whereas the rate of correct diagnosis of staging by CT was markedly improved, 89.3%. In particular, CT facilitated correct diagnosis of T4. Supraglottic T3 cancer is diagnosed on the basis of deep infiltration or fixation of the hemi-larynx. Disappearance of the pre-epiglottic space or ulcer formation was recognized as a CT finding of deep infiltration. Disappearance of the paraglottic space and dislocation of the arytenoid cartilage were used as the standard for CT findings of laryngeal T3 cancer. CT allowed diagnosis to be made in 84.4% of cases which were pathologically determined to be T4. It can be said that CT is a very effective method for staging diagnosis in patients with laryngeal cancer. Fifty-seven patients with hypopharyngeal cancer and cancer of the cervical esophagus were also examined. When 40 post-surgical patients were compared according to pathological classification of T, the rate of correct diagnosis of clinical staging was 77.5% while that of staging diagnosis by CT was 82.5%. The rate of correct diagnosis by postoperative CT was 80.0% compared with the pathological determination of depth of invasion. The diagnosis of depth of invasion by CT on initial examination is thus an effective means for the determination of prognosis.

Adult↗
PubMed1986

[Postoperative recurrence and death rates of poorly differentiated carcinoma of the thyroid].

Postoperative recurrence and death rates of 54 cases of poorly differentiated thyroid carcinoma were analyzed. The rates of recurrence of 18 widely resected cases during 1979 and 1981 and 36 patients undergoing conventional surgery during 1965 and 1978 were 22.2% and 50%, respectively. The difference between the figures was statistically significant (p less than 0.05). The death rates of the two groups were 5.6% and 41.7%, respectively. These results indicate that wide resection is appropriate in the surgical treatment of the thyroid.

Carcinoma↗
PubMed1986

[Vascular invasion, lymph node metastasis and extraglandular extension of well-differentiated carcinoma of the thyroid].

Forty-five surgically removed thyroid glands with well-differentiated carcinoma were histologically analyzed to clarify the relationships among vascular invasion, lymph node metastasis and extraglandular extension. Using Victoria blue-HE stain, vascular invasion can be detected as the evident finding of circular elastic fibers surrounding the cancer cluster. In our series, 60% of the subjects were positive for vascular invasion. Patients with vascular invasion tend to show lymph node metastasis and/or extraglandular extension. This correlation was statistically significant. Therefore, in a patient with lymph node metastasis and/or extraglandular extension, there is a greater possibility of vascular invasion being present as well.

Adult↗
PubMed1985

Preparation and specificity of avian anti-GM2(NeuGc) ganglioside antiserum.

Antibodies to N-glycolyl neuraminic acid-containing GM2 ganglioside, GM2(NeuGc), were prepared by immunizing chickens. The specificity of the antibodies was examined by the double immunodiffusion test and solid-phase radioimmunoassay (RIA). One(C-4) of two antisera produced did not cross-react with GM3(NeuGc) but the other(C-3) did as assessed by the double immunodiffusion test. In RIA, the antibody activity of C-4 antiserum was detected only in the IgG fraction. Specificity of the serum was examined using authentic glycolipids which were structurally related to GM2(NeuGc). The antiserum showed a high specificity for the homologous ganglioside by either an RIA or an inhibition assay. This antiserum is a useful tool for the detection of GM2(NeuGc) in human and animal tissues under normal and/or disease condition.

Animals↗
PubMed1985

In vitro antigenic reactivity of synthetic lipid A analogues as determined by monoclonal and conventional antibodies.

Cross-reactivities of synthetic lipid A analogues with monoclonal and conventional antibodies against Salmonella lipid A were studied. It was shown that the in vitro antigenicity of a synthetic compound 506, beta-(1----6) D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated at 2'-amino and 3'-hydroxyl groups with (R)-3-dodecanoyloxytetradecanoyl and (R)-3-tetradecanoyloxytetradecanoyl groups, respectively, and has (R)-3-hydroxytetradecanoyl groups at 2-amino and 3-hydroxyl groups, was practically indistinguishable from that of the natural E. coli lipid A preparation, and that both phosphates in positions 1 and 4' as well as ester- and amide-linked fatty acyl residues, particularly 3-acyloxyacyl group, of the glucosamine disaccharide are involved in the cross-reactivity of lipid A as important antigenic determinants.

Animals↗
PubMed1985

In situ immunological determination of basic carbohydrate structures of gangliosides on thin-layer plates.

An immunological method for the determination of the basic carbohydrate structure of gangliosides by using a thin-layer chromatographic immunostaining technique was developed. After high-performance thin-layer chromatography of gangliosides, the chromatogram is treated with a 0.4% polyisobutylmethacrylate solution. Arthrobacter ureafaciens neuraminidase is then applied to the separated gangliosides in situ on the chromatographic plate. This procedure will remove both external and internal sialic acid residues from the core oligosaccharide backbone. The resulting glycolipid products are then incubated with anti-Gg4 serum and 125I-staphylococcal protein A, successively, and exposed to an X-ray film. Through a highly specific binding, the anti-Gg4 antibody detects only those gangliosides having the oligosaccharide backbone of Gg4.

Antibodies↗
PubMed1985

A combined modality for anaplastic large-cell carcinoma of the thyroid.

The survival rates of 55 patients with anaplastic large-cell carcinoma of the thyroid with various combinations of treatment were analyzed to estimate the most effective way to cure the disease. A total of 21 patients with infiltration into subclavial vessels, plexus brachialis, vagus, sympathics, phrenic nerve, and/or hypoglossus died within 7 months after the diagnosis and most of them died within 2 months. The prognosis of patients with such tumor infiltration was very poor. Among 34 patients without infiltration of the above-mentioned structures, 12 were treated by radiation therapy alone or with chemotherapy, 8 were treated by surgery plus radiation therapy, and 13 were treated by a combination treatment consisting of operation, radiation, and chemotherapy. The post-therapeutic one-year survival rates were 7.7, 12.5, and 75%, respectively. Therefore, it is concluded that a combination treatment of surgical operation and radiotherapy plus chemotherapy should be the best for treatment of this tumor.

Adult↗