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Biomedical subjects

T Shinohara

Publications and source records attributed to T Shinohara.

At least 235 records · Page 13Linked to original sources
PubMed1991

Expression of S-antigen in retina, pineal gland, lens, and brain is directed by 5'-flanking sequences.

S-antigen (S-Ag) is an abundant protein of the retina and pineal gland that elicits experimental autoimmune uveitis and pinealocytis in several animal species. To study the elements regulating the expression of S-Ag, we generated transgenic mice expressing the chloramphenicol acetyl transferase (CAT) gene under the control of a 1.3-kilobase pair 5'-flanking segment of the mouse S-Ag gene. While all of the transgenic mice expressed CAT activity in the retina, in some animals CAT activity was also detected in the pineal gland, lens, and brain. Immunoblotting, polymerase chain reaction-mediated detection of RNA, and immunocyto-staining of transgenic tissues with antibodies to CAT and S-Ag established that the profile of expression of the transgene corresponded to that of S-Ag; both proteins were detectable in retinal photoreceptor cells, pinealocytes, lens fiber and epithelial cells, the cerebellum, and the cerebral cortex. These results indicate that S-Ag is expressed in a wider spectrum of the cell types than previously recognized and that a 1.3-kilobase pair S-Ag promoter segment contains sufficient information to direct appropriate tissue-specific gene expression in transgenic mice.

Animals↗
PubMed1991

Superoxide anion hyperproduction by neutrophils in a case of myelodysplastic syndrome. Association with Sweet's syndrome and interstitial pneumonia.

The complication of Sweet's syndrome and interstitial pneumonia occurred in a patient with myelodysplastic syndrome. Superoxide anion production by the patient's neutrophils was considerably higher than that by neutrophils obtained from normal controls after stimulation with opsonized zymosan, phorbol myristate acetate, or myristic acid. Prednisone, which a potent inhibitor of superoxide anion production by neutrophils, dramatically improved the skin and pulmonary lesions, suggesting that they were parts of the same clinical spectrum associated with the superoxide anion hyperproduction.

Dermatitis↗
PubMed1991

Distribution of atrial natriuretic peptide in the conduction system and ventricular muscles of the human heart.

Atrial natriuretic peptide (ANP), a cardiac hormone, is known to be located in the atrial specific granules, but its presence and localization in the ventricular muscle of the human heart has not been examined fully. Using a specific antibody to human ANP, we studied the conduction system and ventricular muscle with immunohistochemical and ultrastructural methods in 30 hearts obtained at autopsy. These included 12 normal and 18 diseased hearts. In the normal hearts, ANP-positive granules, which were regularly observed in the atrial myocytes, were found in small quantities in the cells of the penetrating and branching bundles in 4 of 12, and in the cells of the ventricular free walls in 2 of the 12 hearts. In the diseased hearts, the positivity increased significantly (P less than 0.05), being found in 13 of 18 (72.2%) conduction systems and 10 of 18 (55.6%) ventricular muscles. The granules were confirmed to be immunoreactive with ANP by ultrastructural examination. Furthermore, the presence of ANP mRNA in the conduction system as well as in the ventricular myocytes was demonstrated by Northern blot hybridization for which we used the complementary DNA of human ANP. Thus, a small quantity of ANP appears to be synthesized and stored in the conduction system and ventricles of some normal hearts. However, ANP was shown to be present in a larger percentage of the diseased hearts.

Aged↗
PubMed1991

Transforming genes and chromosome aberrations in therapy-related leukemia and myelodysplastic syndrome.

The presence of activated transforming genes was investigated in four patients with therapy-related leukemia and in three with therapy-related myelodysplastic syndrome. DNA of bone marrow cells from six of the patients exhibited transforming activity in the tumorigenicity assay. Five of the six patients who were positive in the tumorigenicity assay contained activated N-ras oncogenes, and three contained activated K-ras oncogenes. Thus, concurrent activation of N-ras and K-ras oncogenes was observed in two patients. In vitro DNA amplification followed by oligonucleotide dot-blot analysis was used to investigate mutations in codons 12, 13, and 61 of the N-ras and K-ras oncogenes. Two patients exhibited an N-ras mutation, substituting aspartic acid (GAT) for glycine (GGT), and three patients exhibited an N-ras codon 13 mutation, substituting valine (GTT) for glycine. Two patients exhibited K-ras codon 12 mutations, substituting aspartic acid (GAT) or cysteine (TGT) for glycine (GGT), respectively, and one case exhibited a K-ras codon 61 mutation, substituting lysine (AAA) for glutamic acid (CAA). Cytogenetic analysis revealed that loss of chromosome 7 was frequent (four patients: 57%). Our data indicate that activation of N-ras and K-ras genes, as well as loss of heterozygosity for specific alleles on chromosome 7, plays a more important role in the leukemogenesis of both therapy-related leukemia and myelodysplastic syndrome.

Aged↗
PubMed1991

Partial 18q trisomy and 18p monosomy resulting from a maternal pericentric inversion, inv(18)(p11.2q21.3).

A 7-year-old boy with dysmorphic features was found to have a recombinant chromosome 18, rec(18), resulting from meiotic recombination of a maternal pericentric inversion, inv(18) (p11.2q21.3), as defined by high-resolution banding. He was trisomic for the long arm (q21.3-qter) and monosomic for the short arm (p11.2-pter) of chromosome 18. His clinical features were compared with those in other rec(18) cases, and also those in monosomy 18p, trisomy 18qter and full trisomy 18 syndromes. The risk of recombinant formation for inv(18) carriers was also discussed.

Abnormalities, Multiple↗
PubMed1991

The relationship between the site of breakpoints within the bcr gene and thrombopoiesis of Philadelphia-positive chronic myelocytic leukemia.

We determined the position of the breakpoint within the bcr gene in 22 patients with Philadelphia-positive chronic myelocytic leukemia using conventional Southern-blots and analyzed its relationship to thrombopoiesis. After DNA digestion with restriction endonucleases (Hind III, Bam HI and Bgl II), we localized the breakpoint in bcr using two genomic probes. The location of the breakpoint within the bcr was assigned to one of five zones. Breakpoints in zones 1 and 2 were grouped as "5"', and those in zones 3, 4 and 5 as "3'". Thus we subdivided patients with bcr rearrangements into those with genomic breaks at either 5' or 3' of the Bam HI site, just upstream of exon 3. Nine patients had 5' breakpoints and 13 patients had 3' breakpoints. The platelet counts of 3' patients were significantly higher than those of 5' patients (1395 vs 274 x 10(9)/l; p less than 0.03). The megakaryocyte counts from bone marrow histological sections in 3' patients (n = 12) and 5' patients (n = 7) were 63.4/mm2 and 19.5/mm2, respectively, with a significant difference of p less than 0.006. The mean number of megakaryocyte progenitor cells assayed by in vitro cloning was 128.3/2 x 10(5) bone marrow cells for 3' patients (n = 7) compared with 46.3 for 5' patients (n = 4). These results suggest that Philadelphia-positive CML patients with 3' breakpoints have higher thrombopoietic activity than patients with 5' breakpoints.

Adult↗
PubMed1991

The gene for retinal rod 33-kDa protein is on mouse chromosome 1, near Lamb2.

A water-soluble protein (called "33-kDa protein") that exhibits light-dependent phosphorylation has been shown to be a major protein of mammalian rod photoreceptors. Although the function of this protein is unknown, it has been implicated in the biochemical cascade mediating the rod visual response. Using a retinal cDNA from the rat and somatic cell hybrids, we have mapped the gene corresponding to this protein to mouse Chromosome 1 and, by analyzing the progeny of an intersubspecific backcross, have positioned it near Lamb2 (the beta 2 chain of laminin). We have designated the gene Rpr-1 (rod photoreceptor protein-1).

Animals↗
PubMed1991

Photoneural control of the synthesis and phosphorylation of pineal MEKA (phosducin).

MEKA is an acidic 33-kilodalton phosphoprotein found in the retina and pineal gland. It is of interest because it forms a cytoplasmic heterotrimer with the beta gamma-complex of GTP-binding regulatory proteins (G proteins). Accordingly, MEKA may play a role in signal transduction. MEKA is phosphorylated on Ser73 by cAMP-dependent protein kinase. In the present report, MEKA was studied using an antiserum (Anti-32) against MEKA65-96, which can be used to estimate total MEKA and the phosphorylation state of MEKA. It was confirmed that MEKA is rapidly phosphorylated by adrenergic stimulation of pineal glands in organ culture. In addition, total (dephosphorylated) MEKA was observed to increase after a 6-h treatment with norepinephrine or (Bu)2 cAMP, an effect which was dependent upon new protein synthesis. In in vivo studies, it was found that the total amount of MEKA and MEKA phosphorylation were increased at night in the dark, a time when the pineal gland is adrenergically stimulated. The high level of phosphorylation was rapidly reduced when animals were exposed to light, which blocks neural stimulation of the gland. This report provides the first in vivo evidence that MEKA phosphorylation is under physiological control, and that MEKA synthesis is controlled by an adrenergic----cAMP mechanism which requires protein synthesis.

Animals↗
PubMed1991

Molecular pathologic study of human papillomavirus infection in inverted papilloma and squamous cell carcinoma of the nasal cavities and paranasal sinuses.

Nasal inverted papilloma is a rare benign tumor occasionally associated with squamous cell carcinoma. To determine the etiological role of human papillomavirus in inverted papilloma, and to clarify the relationship between human papillomavirus and malignant transformation of this benign tumor, we retrospectively analyzed inverted papillomas from 26 patients, 7 of whom had squamous cell carcinoma. We used an immunohistochemical method and molecular pathologic techniques, or dot-blot hybridization of DNA extracted from paraffin-embedded tissues, in situ hybridization, and polymerase chain reaction. Human papillomavirus was detected in 5 of 26 patients (19%), 3 patients with human papillomavirus 11 and 2 patients with human papillomavirus 16. The latter 2 patients had inverted papillomas associated with squamous cell carcinoma. We speculate that human papillomavirus may be related to the malignant transformation of inverted papillomas.

Adult↗
PubMed1991

[The significance of CA-50, SLX and ST-439 in lung cancer].

Serum levels of CA-50, SLX and ST-439 were measured in 213 patients with lung cancer (92 adenocarcinomas, 63 squamous cell carcinomas, 37 small cell carcinomas and 21 large cell carcinomas) and 87 patients with benign lung disease. The overall positive rates in patients with lung cancer were 12.8% for CA-50, 29.7% for SLX and 25.3% for ST-439. The positive rates for CA-50, SLX and ST-439 in adenocarcinoma patients were 22.8%, 42.4% and 38.0%, respectively. Of the patients with benign lung disease, 4.8% were false positive for CA-50, 15.3% for SLX and 3.6% for ST-439. In the patients with adenocarcinoma of the lung, the combination assay of CEA and ST-439 had a highly accurate rate (61.9%).

Adenocarcinoma↗
PubMed1991

[HTLV-I tax mediated activation of cellular genes in transgenic mice].

The tax protein of human T-cell leukemia virus type I (HTLV-I) is known to be a potent transactivator of its own long terminal repeat (LTR) promoter and the cellular genes (IL-2, IL-2R, c-fos and GM-CSF). These effects of tax have been studied in vitro, mostly in T-cell lines. To determine its function in vivo in multiple cell types, we have used two transgenic mouse lines in which tax is expressed under the control of the LTR (LTRtax) or murine Thyl. 2 (Thytax) transcriptional regulatory sequences. Tax protein is expressed in fibroblasts, salivary gland, skeletal muscle, bone matrix and thymus tissue. In these tissues the expression of endogenous IL-2R, c-fos, GM-CSF, Zif268, IL-6, and PDGF-B were studied. In fibroblastic tumors GM-CSF, IL-6, PDGF-B, Zif268, c-fos were expressed at high levels. No significant changes in expression of these genes were seen in other tissues. This suggests that tax mediated transcriptional transactivation alone is not sufficient to cause accumulation of these cellular gene products. Other events which occur during tax mediated transformation in vivo allow high levels of cellular gene expression constitutively.

Animals↗
PubMed1991

[A case of brain infarction associated with viral encephalitis: MRI and pathological findings].

A 10-year-old girl had an infarction in the left brain during an acute viral meningoencephalitis. She initially showed seizure, unconsciousness and fever, and right hemiplegia gradually developed. She died at the 48th day of disease from respiratory disturbance and renal failure. Cranial MRI during the acute phase of the disease, when there was no clinical sign of right hemiplegia, showed a high intensity lesion in the left parietal and occipital areas on T-2 weight image. Autopsy disclosed the findings suggesting viral encephalitis, including multiple focal necrosis, perivascular round cell infiltration, proliferation of glial cells and spongy degeneration with some intranuclear inclusion bodies, and infarction in the left hemisphere. These findings suggest that T-2 high intensity lesion on MRI reflected infarction.

Cerebral Infarction↗
PubMed1990

Cytokine-mediated activation of a neuronal retinal resident cell provokes antigen presentation.

The retinal pigment epithelial (RPE) cell has long been considered an important regulatory cell, maintaining physiological and structural balance within the retina. We have previously shown that the RPE cell may also be important in autoimmunity and transplantation. These cells can be induced by cytokines to express MHC class II Ag in ocular inflammatory and autoimmune conditions. In this report we show that isolated rat RPE cells can be induced to express class II Ag following incubation with rat rIFN-gamma. The ability of RPE cells to present Ag was determined by both T cell proliferation assays and IL-2 production. Only the Ia-positive RPE cells can present retinal Ag (S-Ag and interphotoreceptor-binding protein) to specifically sensitized rat Th cells. Moreover, the ability of chloroquine to inhibit this activity suggests that the RPE cell is also capable of processing Ag prior to Ag presentation. These studies indicate that cytokine-mediated activation of RPE cells may be a basic component of ocular immunity and an important aspect of RPE cell transplantation.

Animals↗
PubMed1990

Structural organization of the human S-antigen gene. cDNA, amino acid, intron, exon, promoter, in vitro transcription, retina, and pineal gland.

S-Antigen (S-Ag) is a major soluble photoreceptor protein involved in the visual transduction cascade. Several S-Ag cDNAs and a gene coding for human S-Ag were isolated from cDNA and gene libraries. The gene sequences of the coding, noncoding, and 5'-flanking regions of the gene were determined. The S-Ag gene was approximately 50 kbp (kilobase pairs) in length and contained 16 exons and 15 introns. The length of most exons was less than 100 base pairs (bp) and the smallest one was only 10 bp. In contrast, the length of most introns was larger than 2 kbp, and the gene comprised 97% intron and 3% exon. The splice sites for donor and acceptor were in good agreement with the GT/AG rule. The S-Ag protein of 403 amino acid residues was translated from a mRNA of 1.9 kbp, and the mRNA was transcribed from a gene of 50 kbp. The 5'-flanking region of the gene, approximately 1.1 kbp long, had no known regulatory elements for transcription such as TATA, GC, and CCAAT boxes. Interestingly, the 5'-flanking region had promoter activity in an in vitro transcription assay using a nuclear extract of rat brain. A major transcription start site was found at 387 bp upstream from the translation start site ATG. Our results indicate that the sequence of S-Ag promoter differs from other known promoters and may, perhaps, be specific for photoreceptor rod cells and pinealocytes.

Amino Acid Sequence↗
PubMed1990

Cellular immune responses of patients with uveitis to retinal antigens and their fragments.

Of two patient populations totaling 82 patients, one in the United States and the other in Japan, we studied the cellular immune responses against S-antigen and interphotoreceptor retinoid binding protein as well as to fragments of each antigen. Behçet's disease, birdshot retinochoroidopathy, pars planitis, ocular sarcoid, sympathetic ophthalmia, and the Vogt-Koyanagi-Harada syndrome were diagnosed in these patients. The response profile of both antigens paralleled each other. This profile was more commonly seen in patients suffering from diseases affecting the retina. Responders reacting to both antigens or to several fragments of an antigen were present. This pattern of response was seen in 26 of the patients tested. Patients with uveitis appeared able to recognize several autoantigens. This might be a consequence of the breakdown of the blood-retinal barrier and may help perpetuate the inflammatory process. Several patients were capable of responding to more than one epitope of the same antigen, which indicates that there are major differences between the experimental model and human autoimmune diseases in the response to autoantigens. Both of these findings may to help develop new immunotherapeutic strategies in the treatment of uveitis.

Adolescent↗