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Biomedical subjects

N Okada

Publications and source records attributed to N Okada.

At least 397 records · Page 22Linked to original sources
PubMed1989

20 KDa homologous restriction factor of complement resembles T cell activating protein.

We previously identified a 20KDa membrane glycoprotein 1F5 antigen which inhibits the assembly of homologous complement membrane attack complexes and we designate it as HRF20 standing for 20KDa homologous restriction factor. The amino acid sequence deduced from its coding base sequence resembles that of T cell activating protein, most conspicuously in cysteine residues, 10 out of 11 of which occupy identical positions in an overall sequence homology of 24.8%. Furthermore, proliferation of human T cells was stimulated by monoclonal antibody to HRF20.

Amino Acid Sequence↗
PubMed1989

Characterization of a new termination signal for RNA polymerase III responsible for generation of a discrete-sized RNA transcribed from salmon total genomic DNA in a HeLa cell extract.

A new type of termination signal for RNA polymerase III transcription has been identified. A cloned DNA from salmon highly repetitive sequences, designated as Sm2, serves as a template for an RNA with about 140 nucleotides, but the clone does not have four or more consecutive T residues in the presumed termination site. S1 nuclease mapping analysis clearly demonstrated that termination occurred at the beginning of the AT-rich sequence in the 3' region of Sm2. Studies with a series of 3'-deletion mutants strongly suggested that an AT sequence of more than nine nucleotides functioned as a terminator. Furthermore, results with another series of 3'-deletion mutants showed that a sequence of only nine nucleotides (ATATATATT) in the noncoding strand in fact functioned as a terminator (designated as the 9AT terminator), although with relatively low efficiency compared to a tract of TTTT introduced downstream, and that new cryptic termination sites were introduced in the upstream slight AT-rich region by approach of the 9AT terminator. An AT-rich region downstream from the actual termination site of Sm2 DNA may enhance the efficiency of termination by facilitating detachment of RNA polymerase from the template DNA. Since the nucleotide sequence around the termination site appears to be conserved in the salmon repetitive sequences, this new terminator may be responsible for the generation of a discrete-sized RNA transcribed from salmon total genomic DNA in vitro.

Animals↗
PubMed1989

Synthesis of epidermolysis bullosa acquisita antigen by simian virus 40-transformed human keratinocytes.

The synthesis of epidermolysis bullosa acquisita (EBA) antigen in simian virus 40 (SV40)-transformed human epidermal keratinocytes was studied. Indirect immunofluorescent staining of SV40-transformed keratinocytes employing a serum sample from an EBA patient as a source of antibodies decorated EBA antigen as a perinuclear granular fluorescence. This staining pattern was similar to that of nontransformed epidermal keratinocytes grown in a low Ca2+ medium. In contrast, stratified primary cultures of keratinocytes stained after growth in a high Ca2+ medium showed only small amounts of the antigen localized in the substrate-attached basal cells. To demonstrate biosynthesis of the EBA antigen by SV40-transformed keratinocytes, cells were metabolically labeled with 14C-amino acids and the cell lysates were immunoprecipitated with EBA antiserum. Analysis of immunoprecipitates by sodium dodecylsulfate-polyacrylamide gel electrophoresis and fluorography revealed that the EBA serum precipitated a protein with an apparent molecular weight of 290 kD from extracts of these cells. These results indicate that SV40 induces the synthesis of the 290 kD EBA antigen. Expression of this antigen may be a general feature of nonstratifying, proliferating epidermal cells.

Amino Acids↗
PubMed1989

Loss of virulence in Shigella strains preserved in culture collections due to molecular alteration of the invasion plasmid.

Fifty-two Shigella strains long preserved by three Japanese culture collections were examined for virulence. All of them were avirulent when judged by the focus-plaque assay and the ability to bind Congo red. Fifteen strains had a plasmid comparable in size to that responsible for epithelial invasiveness and were positive in hybridization tests with a probe derived from a plasmid cistron, virG. Twenty-four strains had a similar plasmid but were negative in hybridization tests. The remaining 13 strains were negative in all the five criteria for virulence. Similar studies made on one hundred Shigella strains isolated from 1967 to 1985 clearly demonstrated loss of virulence with prolonged time of storage.

DNA, Bacterial↗
PubMed1989

Cutis laxa with ultrastructural abnormalities of elastic fiber.

A case of a congenital, autosomal recessive form of generalized cutis laxa is reported. The patient was a 27-month-old boy with generalized flaccid skin and short stature. Radiologic examination revealed that the age of the bones of the wrist was compatible with a chronologic age of only 1 year. Elastic fibers were diminished throughout the dermis, and results of electron microscopic study showed globular and unstained elastin and relatively large amounts of the microfibrillar components of elastic fibers.

Biopsy↗
PubMed1989

Isolation, sequence, and bacterial expression of a cDNA for (S)-tetrahydroberberine oxidase from cultured berberine-producing Coptis japonica cells.

cDNA clones for the (S)-tetrahydroberberine (H4Ber) oxidase of cultured berberine-producing Coptis japonica cells were isolated by screening a C. japonica cDNA library with synthetic nucleotides that can encode the NH2-terminal sequence of this enzyme. Analyses of the nucleotide sequences of the cloned cDNA inserts revealed a 759-base-pair open reading frame that encoded a 253-amino acid polypeptide with a Mr of 27,089 and NH2-terminal and internal sequences identical with those of the (S)-H4Ber oxidase, as determined by microsequencing methods. Escherichia coli were transformed with an expression vector carrying (S)-H4Ber oxidase cDNA. The transformed bacteria were induced to overproduce a 28-kDa protein that reacted with Coptis (S)-H4Ber oxidase-specific antibody. A comparison of the derived amino acid sequence of (S)-H4Ber oxidase with sequences in the protein data base of the Protein Research Foundation showed a marked similarity between (S)-H4Ber oxidase and the NH2-terminal portion of mouse P1-450, which is encoded by a single exon of the mouse P1-450 gene. The availability of cloned cDNA for (S)-H4Ber oxidase allows use of the methods of molecular biology to study the regulation of (S)-H4Ber oxidase gene expression in cultured C. japonica cells in relation to berberine biosynthesis.

Amino Acid Sequence↗
PubMed1989

Primary structure of cucumber (Cucumis sativus) ascorbate oxidase deduced from cDNA sequence: homology with blue copper proteins and tissue-specific expression.

cDNA clones for ascorbate oxidase were isolated from a cDNA library made from cucumber (Cucumis sativus) fruit mRNA. The library was screened with synthetic oligonucleotides that encode the NH2-terminal sequence of this enzyme. Nucleotide sequence analysis of the cloned cDNA inserts revealed a 1761-base-pair open reading frame that encoded an NH2-terminal signal peptide of 33 amino acids and a mature enzyme of 554 amino acids (Mr, 62,258). The amino acid sequence deduced from nucleotide sequence analysis agrees with the NH2-terminal amino acid sequence of the purified ascorbate oxidase, as determined by microsequencing methods. Cucumber ascorbate oxidase contained four histidine-rich regions with striking sequence homology to the corresponding parts of the other multicopper oxidases such as Neurospora crassa laccase and human ceruloplasmin and, to some extent, to a low molecular weight copper protein such as plastocyanin. Moreover, these data further support the hypothesis that the small blue copper proteins and the multicopper oxidases have evolved from the same ancestral gene. By RNA blot hybridization analysis, the mRNA for the ascorbate oxidase was found to be abundant in cucumber fruit tissue while expressed at very low levels in leaf and root tissues.

Amino Acid Sequence↗
PubMed1989

A novel membrane glycoprotein capable of inhibiting membrane attack by homologous complement.

Neuraminidase-treated human erythrocytes become sensitive to haemolysis by heterologous serum via activation of the alternative complement pathway (ACP), while remaining insensitive to homologous serum because of the presence of inhibitors on the cell membrane. We obtained a monoclonal antibody which renders the neuraminidase-treated erythrocytes sensitive to haemolysis by homologous human serum via the ACP. This antibody reacts with a 20 KDa membrane glycoprotein which interferes with the terminal stage of complement action on cell membranes. The 20 KDa protein is anchored to the membrane via phosphatidylinositol.

Antibodies, Monoclonal↗
PubMed1989

Expression of proliferating cell nuclear antigen/cyclin in human keratinocytes.

The expression of proliferating cell nuclear antigen (PCNA), also called cyclin, in human keratinocytes was examined by using the serum obtained from a SLE patient and a murine monoclonal antibody against PCNA/cyclin. In the normal epidermis, few of the nuclei were labeled with anti-PCNA/cyclin. This was in contrast to the positive nuclear staining seen in active lesions of psoriasis. In a primary culture of human keratinocytes growing as a monolayer, 20%-30% of cells expressed PCNA/cyclin. SV40-transformed human keratinocytes showed positive nuclear staining in about 40% of the cell population. In stratified keratinocytes cultured in a high Ca++ medium, PCNA/cyclin expression was decreased and only the cells in the basal and suprabasal layers showed positive staining. These results indicate that the expression of PCNA/cyclin correlates with the proliferating state in human keratinocytes and may not be associated with the mechanism of differentiation in keratinocytes.

Antibodies, Monoclonal↗
PubMed1989

Tumor cells treated with vaccinia virus can activate the alternative pathway of mouse complement.

Vaccinia virus has been shown to render mouse tumor cells highly immunogenic. Since we have demonstrated that induction of complement activating capacity on guinea pig tumor cells by Sendai virus infection causes the tumor cells to become immunogenic, we assumed that vaccinia virus infection of mouse tumor cells might render them reactive with homologous mouse complement. Therefore, murine tumor cells, MH134 and X5563, infected with vaccinia virus (VV) were incubated with mouse plasma and C3 deposition was determined by staining with fluorescein isothiocyanate-labeled anti-C3. We found that VV-infected tumor cells possess the ability to activate the alternative complement pathway (ACP) of murine complement. For induction of complement activating ability, at least a 3 h incubation of the infected MH134 cells was required indicating that the generation of ACP-activating capacity on MH134 infected with VV is time-dependent. Furthermore, ultraviolet-irradiated vaccinia virus was able to induce ACP-activating capacity on tumor cells as well.

Animals↗
PubMed1989

Skin pigmentation associated with minocycline therapy.

A patient on long-term minocycline therapy developed blue-black discoloration on the legs. Skin biopsy specimens from the pigmented areas were examined by light and electron microscopy and energy-dispersive X-ray microanalysis. Pigmented granules were present at all levels of the dermis and subcutaneous fat tissues. Ultrastructural examination showed electron-dense granular material within the cytoplasm of dermal macrophages and energy-dispersive X-ray microanalysis indicated that the granules contained iron. Thyroid tissue obtained by aspiration biopsy showed the presence of fine brown granules within the cytoplasm of the follicular epithelial cells. An extract of skin from the pigmented areas was subjected to high performance liquid chromatography and minocycline was detected.

Female↗
PubMed1989

Functional organization and nucleotide sequence of virulence Region-2 on the large virulence plasmid in Shigella flexneri 2a.

The 7 kb virulence Region-2 of the large (virulence) plasmid in Shigella flexneri 2a encodes several proteins required for invasion of intestinal epithelial cells. Insertion and deletion mutagenesis, DNA subcloning and SDS-polyacrylamide gel electrophoresis of proteins synthesized in minicells demonstrated five genes in this region. They encode 24, 18, 62 (IpaB), 41 (IpaC) and 37 (IpaD)-kiloDalton (kD) proteins. Complementation of Tn5-induced mutations in Region-2 with the above plasmid constructs indicated that Region-2 consists of two operons and that the three Ipa proteins are essential for the virulence phenotype. The transcriptional organization determined by Northern blotting, S1 nuclease protection and the effect of Tn5 insertions on expression of the Ipa proteins revealed that Region-2 has three promoters that transcribe RNAs of 4.0, 4.5 and 7.5 kb. The 4.0 kb RNA was the transcript for the operon encoding the 24, 18 kD, IpaB and C proteins and the 4.5 kb RNA for the ipaD gene. In addition, the full-length RNA of 7.5 kb which covers Region-2 supplemented full expression of the Ipa proteins. The 7663 nucleotides of Region-2 were determined to confirm the five open reading frames encoding 23,655, 17,755, 62,168, 41,077 and 36,660 Dalton proteins, respectively, and their regulatory sequences.

Amino Acid Sequence↗
PubMed1989

Molecular cloning and characterization of chromosomal virulence region kcpA of Shigella flexneri.

In Shigella flexneri, in addition to several well-recognized plasmid-borne virulence loci, at least three genetic loci implicated in pathogenesis have been recognized on the chromosome. To understand more about the pathogenesis of bacillary dysentery at a molecular level, the genetically recognized but previously unidentified KcpA region (one of the chromosomal regions near purE) was cloned and sequenced. A single translatable open reading frame encoding a 12310 Dalton protein corresponding to the minicell product was found. Immunofluorescence microscopy, as well as optical and electron microscopic comparison of tissue-cultured cells and guinea-pigs' eyes infected with wild-type or kcpA mutant bacteria, revealed that the kcpA product is required by invading bacteria for spread into adjacent cells.

Amino Acid Sequence↗
PubMed1989

virG, a plasmid-coded virulence gene of Shigella flexneri: identification of the virG protein and determination of the complete coding sequence.

On the 230-kilobase-pair (kb) virulence plasmid of Shigella flexneri 2a strain YSH6000, at least seven separate genetic determinants have been identified. One of them, an approximately 4-kb region, virG, that is required for the Sereny reaction, was extensively studied to examine the role of the virG region. The phenotype of a VirG- mutant (M94) of YSH6000 in the cytoplasm of cultured MK cells was characterized by a kinetic study of the invading shigellae. The observed phenotype of M94 in the cytoplasm indicated that the virG locus is not required for multiplication of the invading shigellae, but is essential for their spread to adjacent cells. The DNA region necessary for the VirG function was localized to a 3.6-kb DNA sequence on the 230-kb plasmid. A 130-kilodalton polypeptide was confirmed to be the virG product. External labeling of bacteria with 125I indicated that the 130-kilodalton virG protein is exposed on the bacterial surface. The nucleotide sequence of 4,472 bp, which contains the functional virG gene and its own regulatory sequence, was determined, and a large open reading frame encoding 1,102 amino acid residues was identified.

Amino Acid Sequence↗
PubMed1989

[Dramatic effects of high-dose intravenous gammaglobulin in each patient with intractable dermatomyositis and polymyositis].

A high-dose intravenous gamma-globulin (IVGG) therapy was given to two children; one with intractable dermatomyositis (case 1) and the other with polymyositis (case 2). Case 1, a 3-year-6-month-old girl, only poorly responded to the standard oral prednisolone therapy and a pulse therapy with high-dose methyl-prednisolone. This patient showed a complete remission after a course IVGG therapy, 100 mg/kg/day iv. for 5 days, which has been maintained for 6 months up to the present. Case 2, a 13-year-6-month-old girl, also showed little improvement after the oral prednisolone therapy, and transient improvement during plasma exchange therapy. This patient showed fairly good response after three repeated courses of IVGG therapy, but not complete remission.

Adolescent↗
PubMed1989

[Statistical analyses of clinical observations made on outpatients visiting the Department of Oral Diagnosis, Meikai University School of Dentistry Hospital, for the past 16 years].

Statistical analyses of clinical observations made on outpatients visiting the Department of Oral Diagnosis, Meikai University School of Dentistry Hospital from June, 1970, to August 1986 were carried out. The total number of new outpatients during this period was 73,708. The results were as follows: 1) The largest number of patients was found in 1978. 2) There was a tendency for the number of new patients to increase in March, June, and August of every year. The smallest number of patients came in December. 3) The greatest number of new patients visiting the hospital was in the 0-9 age category, followed by those in the 20-29 and 30-39 age categories. 4) The greatest chief complaint of patients visiting the hospital was pain, followed by masticatory disturbance and swelling. 5) The number of outpatients coming to the hospital for cosmetic and temporomandibular joint problems has been increasing on a yearly basis over the past 16 years.

Adult↗
PubMed1989

Anaphylactic symptoms due to chlorhexidine gluconate.

Six patients who developed urticaria, dyspnea, and anaphylactic shock due to topical application of chlorhexidine gluconate solution are described. Chlorhexidine gluconate was confirmed as the causative agent of type I hypersensitivity by intradermal, scratch, and epicutaneous tests. To prevent life-threatening adverse reactions, it seems important to use chlorhexidine gluconate on wound surfaces at a concentration of 0.05%, as recommended by the manufacturer; chlorhexidine gluconate may not be suitable for application to mucous membranes.

Adolescent↗