Search PubMed⌕ Search

Biomedical subjects

N Okada

Publications and source records attributed to N Okada.

At least 433 records · Page 24Linked to original sources
PubMed1987

Characterization of human autoantibodies that selectively precipitate the 7SL RNA component of the signal recognition particle.

The signal recognition particle (SRP), which consists of the 7SL RNA molecule associated with six polypeptides ranging between 9,000 and 72,000 m.w., mediates the translocation of newly synthesized proteins across the endoplasmic reticulum. We have characterized autoantibodies that are directed against this particle from two patients with rheumatic diseases. These sera immunoprecipitated the 7SL RNA from whole extracts of HeLa cells radiolabeled with 32P, but no RNA from deproteinized cell extracts. From 35S-methionine-labeled cell extracts, they immunoprecipitated a single polypeptide of 54,000 m.w. that is consistent with a known SRP component. Sucrose density gradient studies confirmed that this protein co-migrated with the 7SL RNA, indicating the likelihood that it is physically associated with this RNA. Thus, the 54,000 m.w. SRP protein, which is essential for the SRP functions of elongation arrest and translocation, appears to be a preferential target for human autoimmune responses. Human autoantibodies that recognize the SRP should be useful adjuncts to animal antisera for studies of the structure and function of this particle.

Arthritis↗
PubMed1987

Tetrahymena actin. Cloning and sequencing of the Tetrahymena actin gene and identification of its gene product.

Actin is ubiquitous in eukaryotes, nevertheless its existence has not yet been clearly proven in Tetrahymena. Here we report the cloning and sequencing of an actin gene from the genomic library of Tetrahymena pyriformis using a Dictyostelium actin gene as a probe. The Tetrahymena actin gene has no intron. The predicted actin is composed of 375 amino acids like other actins and its molecular weight is estimated as 41,906. Both T. pyriformis and T. thermophila possess a single species of actin genes which differ in their restriction patterns. Northern hybridization analysis revealed that the actin gene was actively transcribed in vivo. To detect the gene product, we synthesized an N-terminal peptide of the deduced sequence and prepared its antibody. Using an immunoblotting technique, we identified Tetrahymena actin on a two-dimensional gel electrophoretic plate. The actin spot migrated near an added spot of rabbit skeletal muscle actin, but clearly differed from the latter in its isoelectric point and apparent molecular weight. The primary structure of Tetrahymena actin shares about 75% homology equally with those of other representative actins. This value is extremely low as a homology rate between known actins. Tetrahymena actin diverges not only in relatively variable regions of other actins, but also in relatively constant regions. The hydrophilicity levels of two regions (residues 190 to 200 and residues 225 to 235) are also quite different between the Tetrahymena actin and skeletal muscle actin. Thus, we conclude that actin is present in Tetrahymena, but it is one of the most unique actins among the actins known hereto.

Actins↗
PubMed1987

Sensitization of human tumor cells to homologous complement by vaccinia virus treatment.

Although cell membranes have potent inhibitors which protect the activation of complement on the self cell membranes, some viruses have been shown to activate complement via the alternative pathway on the virus-infected cells. Tumour cells have been made reactive to homologous complement following treatment with such viruses and became highly immunogenic to syngeneic host guinea pigs and mice. Vaccinia virus (VV) made murine tumour cells highly immunogenic thus generating complement activating capacity on the infected cells. Since it has been suggested that VV can make some human tumour cells immunogenic to the cancer patients, we examined VV to see if the virus also has the capacity to make human tumour cells reactive with homologous human complement. Our present results indicate that not only is this the case but ultraviolet-treated VV also has the same effect.

Complement Activation↗
PubMed1987

A case of de novo interstitial deletion 3q.

A rare chromosome abnormality consisting of interstitial deletion 3q was found in a malformed girl. Chromosome analysis using G and Q banding showed deletion of bands 3q12----3q21: 46,XX,del(3)(pter----q12::q21----qter). The clinical features of the proband included severe psychomotor retardation, craniofacial asymmetry, hypertelorism, epicanthus, high arched palate, progressive scoliosis, multiple skin pigmentations, and renal abnormalities. The parents had normal karyotypes.

Abnormalities, Multiple↗
PubMed1987

[A case report of patient with advanced stomach carcinoma of linitis plastica type responding to multi-immunotherapy and chemotherapy].

Multiple-drug (OK-432, PSK and SPG) immunotherapy and chemotherapy provided remission of symptoms for 36 months in a patient aged 21 years suffering scirrhous gastric carcinoma associated with carcinomatous peritonitis in which direct infiltration to the pancreas, retroperitoneum and the left colon was observed. A remarkable improvement with time was observed by endoscopic and roentgenographic observation, and a substantial improvement was also observed in the NK-cell ratios of lymphocyte subsets of the OKT series in relation to immunologic parameters. A tumor necrosis factor [TNF]-like substance was thought to have been induced by multiimmunotherapy in this case.

Adenocarcinoma, Scirrhous↗
PubMed1987

[The effect of tegafur suppository and glutathione in patients with gastric and colonic cancer with special reference to the histopathological anticancer effect].

The purpose of these studies is to evaluate the anticancerous effects of tegafur suppository and Glutathione (GSH) as enhanced drug and compare the difference of the histopathological effects and tissue concentration of 5-FU and FT-207 in gastric and colon cancer. Thirty three patients with gastric cancer and 17 with colon cancer were treated by tegafur suppository at a dose of 1,500 mg/day and GSH, 1,200 mg/day intravenously. These patients were clinically divided into two groups, one of which was treated with tegafur suppository (Group A) and another administered with suppository and GSH (Group B). Five-fluorouracil was measured by GC-MF method and FT-207 was also done by HPLC method. After surgery, relationship between tissue concentration of 5-FU and histopathological effects were investigated. In gastric cancer, 5-FU concentration in cancer tissue was significantly kept high level in cancer tissue in patients treated with tegafur and GSH (Group B). However, there was no same results in colon cancer. These results seemed to be the difference of organ specificity. According to histopathological studies, well differentiated adenocarcinoma including papillary carcinoma were markedly effective compared to poorly differentiated adenocarcinoma in both cancer. This difference of anticancerous effect was supposed to be microangiographically different of microvascular architecture and quantity of anticancerous agents in tumor.

Colonic Neoplasms↗
PubMed1987

[Idiopathic calcinosis of the scrotum: a case report].

A 25-year-old man complained of painless, firm scrotal nodules which increased in number and size for the last 7 years. Physical examination was unremarkable except for many, firm painless nodules near the scrotal raphe. Preoperative diagnosis was multiple scrotal tumors of unknown etiology. Surgical excision was performed under epidural anesthesia. On microscopic examination, the nodules were located in the dermis and composed of calcified material which was positive with the von Kossa calcium stain. There were numerous foreign giant cells and dense fibrosis at the margins of the lesions. Idiopathic calcinosis of the scrotum was the final diagnosis. Although its etiology is unknown, the literature reviewed supported the view that the mast cell accumulation and its degranulation are related to idiopathic calcinosis of the scrotum.

Adult↗
PubMed1987

Effect of 3-[p-(trans-4-aminomethylcyclohexylcarbonyl)-phenyl] propionic acid hydrochloride on gastric mucosal blood flow.

The effects of 3-[p-(trans-4-aminomethylcyclohexylcarbonyl)phenyl]propionic acid hydrochloride (TEI-5103, TG-51) on gastric mucosal blood flow (GMBF) in rats, rabbits, and dogs were studied by using hydrogen gas clearance, cross-thermocouple, and 51Cr-labelled erythrocyte methods. TEI-5103 (5 mg/kg i.v.) increased GMBF, measured by hydrogen gas clearance method, in anesthetized rats. At 1-10 mg/kg i.v. it also increased GMBF, measured by cross-thermocouple method, in anesthetized rabbits and dogs. The increasing effect of TEI-5103 was more potent than that of cetraxate. By the intragastric route, TEI-5103 (400 mg/kg) increased the GMBF 1 h after the administration in anesthetized and pylorus-ligated rats. Anti-ulcer doses of TEI-5103 prevented the decrease in the GMBF induced by serotonin or indomethacin in anesthetized rats. The drug also prevented the decrease in gastric mucosal blood volume induced by serotonin. The increase in dog femoral arterial blood flow by TEI-5103 (1-10 mg i.a.) was not affected by propranolol, atropine, diphenhydramine, or aminophylline, nor was it attenuated by pretreatment with indomethacin. TEI-5103, like papaverine, inhibited Ca2+-, PGF2 alpha- and norepinephrine-induced contractions of isolated rabbit coeliac artery. The results indicate that TEI-5103 increases GMBF by acting directly on the gastric microcirculation and that this increasing effect may contribute to the anti-ulcer activity of TEI-5103.

Anesthesia↗
PubMed1986

TPA-induced alteration of actin organization in cultured human keratinocytes.

Distribution of actin filaments of human epidermal keratinocyte in the primary culture was observed by immunofluorescence staining. In the cytoplasm, actin was distributed diffusely, and strong antiactin immunofluorescence was observed along the leading edge, showing ruffling and the contact zone to the neighboring cell. 12-O-Tetradecanoylphorbol-13-acetate (TPA) induced organization of actin filaments. Many short bundles of actin filaments appeared shortly after the addition of 16 nM TPA, and large actin-containing ribbons of crescent-shape, circular or gyrus-like form were sometimes observed. Phorbol-12-13-diacetate, a non-promoter phorbol ester, induced a similar change, but to a much lesser extent. Addition of 1 mM cycloheximide did not interfere with the organization of actin filaments by TPA. La3+ aborted it completely possibly by replacing Ca2+ at the binding site of the cell surface, and the cultivation in low Ca2+ environment suppressed the effect of TPA. These findings make a contrast to those reported in fibroblasts, and may be linked to the characteristic response of cultured human keratinocytes to TPA in the proliferation of cells and induction of ornithine decarboxylase.

Actins↗
PubMed1986

A new disk method for the endoscopic determination of gastric ulcer area.

The authors devised a new method using measure plates for the endoscopic measurement of gastric ulcer area. A grid composed of 2.5-mm squares was photographed by the endoscope with lens-object-distance (LOD) being changed every 2.5 mm precisely, and the obtained images of the square pattern were printed on glass plates, which were used as measure plates. The ulcer size was determined by mounting an endoscopic photograph of the ulcer on the corresponding glass plate with the same LOD, projecting them on the screen by a projector and counting the number of squares within the ulcer area. In this way the gastric ulcer size could be determined with an average aberration ratio of 5.6% or less, irrespective of LOD.

Gastroscopy↗
PubMed1986

Gene for lysine tRNA1 may be a progenitor of the highly repetitive and transcribable sequences present in the salmon genome.

When salmon total DNA was transcribed in a HeLa cell extract, a discrete 6S RNA was found to be synthesized by RNA polymerase III. We isolated several phage clones containing the 6S RNA gene from a salmon genomic library and determined the sequences of two representative clones. The 5' part of the gene showed remarkable sequence homology with the lysine tRNA1 molecule. This homology extended to secondary structures, and the numbers of nucleotides in the stem and loop structures in the 6S RNA were the same as those in lysine tRNA1. Further, the pseudouridylic acid residues synthesized by HeLa pseudouridylate synthase(s) were determined to be at uridine-27 and uridine-55, which are the positions of these modified nucleosides in lysine tRNA1. These results strongly suggest that the lysine tRNA1 gene is a progenitor of the highly repetitive and transcribable sequences in the salmon genome.

Animals↗