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Biomedical subjects

N Okada

Publications and source records attributed to N Okada.

At least 451 records · Page 25Linked to original sources
PubMed1986

Total DNA transcription in vitro: a procedure to detect highly repetitive and transcribable sequences with tRNA-like structures.

Total DNAs from various animals were transcribed in vitro in a HeLa cell extract, and it was found that one to several discrete RNAs were transcribed by RNA polymerase III. With tortoise (Geoclemys reevessi) and newt (Cynops pyrrhogaster), distinct 6.5S and 8S RNAs were transcribed from these respective DNAs. Representative phage clones carrying the 6.5S and 8S RNA genes were isolated from genomic libraries of these animals, and the sequences of these genes were determined. The 5' parts of highly repetitive and transcribable sequences of tortoise and newt were found to have close resemblance to tRNALys1 (rabbit) gene (78% homology) and a tRNAGlu (Drosophila) gene (74% homology, not counting the aminoacyl stem region), respectively. The homologies extended to secondary structures, homologous nucleotides being located on similar secondary structures. It is proposed that many, if not all, highly repetitive and transcribable sequences detected by total DNA transcription have specific tRNA genes as their progenitors.

Animals↗
PubMed1986

Gastric functions in patients with the intrathoracic stomach after esophageal surgery.

Functions of the stomach placed in the posterior mediastinum after esophagectomy were studied in 20 esophageal carcinoma patients. Seven were long-term survivors who lived more than 5 years after operation, and five of them showed normal fasting serum gastrin levels and good or fair gastric acid secretion. Of 13 patients who had their operations within 3 years before the study, 11 showed high fasting serum gastrin levels and poor gastric acid secretion. The hepatobiliary and alimentary scintigrams with double isotopes demonstrated a time lag between the excretion of the food from the stomach and the excretion of bile into the bowels, regardless of the postoperative periods. Absorption of vitamin B12 was normal in patients who lived more than 2 years after operation. The intraluminal pressure and pH studies in long-term survivors showed that our operative technique, the posterior invagination esophagogastrostomy, was effective in preventing a gastroesophageal reflux in the anastomosis.

Adult↗
PubMed1986

Expression of pemphigoid antigen by SV40-transformed human keratinocytes.

The expression and properties of pemphigoid antigen of SV40-transformed human keratinocytes were studied. By indirect immunofluorescence, SV40-transformed keratinocytes in passage 80-85 expressed the pemphigoid antigen as coarsely granular perinuclear fluorescence. To characterize this antigen, NP40 extracts of cells labeled with [14C]amino acids were immunoprecipitated using sera of 8 patients: bullous pemphigoid (6 patients), chronic localized pemphigoid (1 patient), and drug-induced lichen planus pemphigoides (1 patient). These immunoprecipitates were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and then fluorographed. All 8 sera precipitated a protein of Mr 240K, while normal human sera did not precipitate this protein. These results indicate that SV40-transformed human keratinocytes synthesize pemphigoid antigen, and that autoantibodies in the sera of pemphigoid patients with different clinical features identify the same antigen of Mr 240K in these cells.

Antigen-Antibody Reactions↗
PubMed1986

Metastasizing atrial myxoma: a case with multiple subcutaneous tumours.

We report a case with rapidly growing subcutaneous and intra-muscular tumours that were identical histopathologically to a pre-existing left atrial myxoma. No invasion of visceral organs or skeleton was found. This is a very rare case of metastasizing myxoma with wide dissemination and rapid metastastic growth, despite the benign appearance of the original tumour.

Adult↗
PubMed1986

Pharmacological action of hachimijiogan (Ba-wei-wan) on the metabolism of aged subjects.

In order to elucidate the active mechanism of traditional Chinese medicine, we investigated the effects of Hachimijiogan which has been alleged to restore the function of old degenerated organs. After administering Hachimijiogan to aged rats and mice, we examined the lipid and glutathione metabolism. The cholesterol and triglyceride levels in the mice liver were significantly decreased in the Hachimijiogan treated group. The cholesterol turnover was examined using labeled cholesterol in aged mice, and Hachimijiogan may increase the turnover of cholesterol metabolism. The lenticular glutathione levels and enzyme activities concerned with glutathione metabolism were investigated in aged rats given Hachimijiogan, suggesting that Hachimijiogan may offer protective and therapeutic effects against senile cataract. From our study, Hachimijiogan is considered to improve the lipid and glutathione metabolism as a result of its complicated in vivo compound effects.

Aging↗
PubMed1986

Neuropathogenesis of Tyzzer's organism in intranasally infected mice.

The neuropathogenesis of Tyzzer's organism was comparatively studied in suckling and weanling mice after intranasal inoculation. In sucklings, suppurative rhinitis was produced in 24 hr postinoculation (p.i.) and organisms were detected in olfactory as well as supporting cells of the nasal mucosa. The lesions later developed to the lamina propria and propagation of organisms was seen within basal and glandular cells. On day 3 p.i., some organisms were found along with the olfactory nerve fibers and within neurons in the olfactory bulbs. Meningoencephalitis was produced with intraneuronal growth of bacteria on day 5 p.i. or later. On day 7 p.i., the brain lesions spread multifocally to the posterior parts and bacterial antigen in the nasal mucosa disappeared. In weanlings, infection was first established in the nasal mucosa and then some necrotized lesions were produced in the olfactory bulbs though much less in severity as compared to those of sucklings. Both suckling and weanling mice had necrotizing hepatitis while hemorrhagic enteritis was seen only in some sucklings.

Administration, Intranasal↗
PubMed1985

5-Methylcytidylic modification of in vitro transcript from the rat identifier sequence; evidence that the transcript forms a tRNA-like structure.

Previous studies showed that the rat identifier sequence, the rodent type 2 Alu family, the rabbit C family and the bovine or goat 73 bp repeat show remarkable resemblance with a few specific tRNA molecules (Sakamoto and Okada, J. Mol. Evol. in press). This paper reports 5-methylcytidylic modification of the in vitro transcript from the ID sequence, and provides further evidence that the transcript forms a tRNA-like structure in vitro. Fingerprint analysis and oligonucleotide mapping suggested that the sequence of the oligonucleotide containing 5-methylcytidine is CpCpm5CpUpGp, which corresponds to the extra and T psi stem regions in the secondary structure of phenylalanine tRNA. Since the sequence of the corresponding oligonucleotide in the phenylalanine tRNA is Cpm5CpCpUpGp, these results suggests that a tRNA (cytosine-5) methyl transferase recognizes the secondary structure of the transcript from the ID sequence rather than the primary sequence. The significance of this modification in relation to the functional role of the ID sequence is discussed.

Animals↗
PubMed1985

Antitumor activities and tumor necrosis factor producibility of traditional Chinese medicines and crude drugs.

The antitumor activities and capacity for tumor necrosis factor (TNF) production of traditional Chinese herbal preparations (Zhu-ling-tang, Xiao-chai-hu-tang), crude drugs (Polyporus, Hoelen, Bupleuri radix, Angelica radix, Cnidii rhizoma, Cinnamomum cortex), and Krestin (PSK) were investigated. These drugs were given to DDY mice in the drinking water before and after transplantation of Ehrlich tumors, and the development of the intradermally transplanted Ehrlich tumors and survival rate were observed. A good survival rate and sometimes a complete cure were found in the groups administered Bupleuri radix, Xiao-chai-hu-tang, Angelica radix, or Cinnamomum cortex, while the group given Hoelen showed poor results. To examine the capacity for TNF production these drugs were given to DDY mice PO as initial stimulating agents, to stimulate the reticuloendothelial system (RES) prior to lipopolysaccharide injection. The TNF activity was tested from the cytotoxicity against L cells. Significant differences in capacity for TNF production were observed among the drugs. Relatively high levels of TNF activity were noted in the groups given Angelica radix, Bupleuri radix, Cnidii rhizoma, or Cinnamomum cortex, very low activities in the groups given Xiao-chai-hu-tang, Zhu-ling-tang, or Krestin, and no TNF activities in the groups given Polyporus or Hoelen. The TNF capacity for production broadly paralleled the survival rate of the mice transplanted to Ehrlich tumors. Our findings suggest that one mechanism underlying the antitumor activities of these drugs is based on stimulation of the RES and is closely related of TNF production.

Animals↗
PubMed1985

Rodent type 2 Alu family, rat identifier sequence, rabbit C family, and bovine or goat 73-bp repeat may have evolved from tRNA genes.

Close structural resemblances between several mammalian highly or moderately repetitive families and some specific tRNAs were detected. The rodent type 2 Alu family, rat identifier (ID) sequences, rabbit C family, and bovine or goat 73-bp repeat are most homologous with lysine tRNA5, phenylalanine tRNA, glycine tRNA, and glycine tRNA, respectively. The homologies extend to secondary structures, and the homologous nucleotides are located on nearly the same secondary structures. The repetitive families mentioned have a common structural organization, with a tRNA-like sequence devoid of an aminoacyl stem region. These features suggest that these repetitive families may be generated by nonhomologous recombination between a tRNA gene and a tRNA-unrelated block.

Animals↗