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Biomedical subjects

Y Iida

Publications and source records attributed to Y Iida.

At least 289 records · Page 16Linked to original sources
PubMed1985

Phylogenetic relationships among eukaryotic kingdoms inferred from ribosomal RNA sequences.

Phylogenetic trees among eukaryotic kingdoms were inferred for large- and small-subunit rRNAs by using a maximum-likelihood method developed by Felsenstein. Although Felsenstein's method assumes equal evolutionary rates for transitions and transversions, this is apparently not the case for these data. Therefore, only transversion-type substitutions were taken into account. The molecules used were large-subunit rRNAs from Xenopus laevis (Animalia), rice (Plantae), Saccharomyces cerevisiae (Fungi), Dictyostelium discoideum (Protista), and Physarum polycephalum (Protista); and small-subunit rRNAs from maize (Plantae), S. cerevisiae, X. laevis, rat (Animalia), and D. discoideum. Only conservative regions of the nucleotide sequences were considered for this study. In the maximum-likelihood trees for both large- and small-subunit rRNAs, Animalia and Fungi were the most closely related eukaryotic kingdoms, and Plantae is the next most closely related kingdom, although other branching orders among Plantae, Animalia, and Fungi were not excluded by this work. These three eukaryotic kingdoms apparently shared a common ancestor after the divergence of the two species of Protista, D. discoideum and P. polycephalum. These two species of Protista do not form a clade, and P. polycephalum diverged first and D. discoideum second from the line leading to the common ancestor of Plantae, Animalia, and Fungi. The sequence data indicate that a drastic change occurred in the nucleotide sequences of rRNAs during the evolutionary separation between prokaryote and eukaryote.

Animals↗
PubMed1985

The complete nucleotide sequence of a rice 25S.rRNA gene.

The complete nucleotide (nt) sequence of a rice nuclear 25S.rRNA gene has been determined. The 25S.rRNA-coding region is 3377 bp long. The G + C content is 59.4%. The structural organization of this rRNA is very similar to that of yeast 26S rRNA.

Base Sequence↗
PubMed1985

Splice-site signals of mRNA precursors as revealed by computer search. Site-specific mutagenesis and thalassemia.

Many eukaryotic genes are interrupted by introns, which are removed from mRNA precursors by the RNA splicing mechanism. Although nucleotide sequences around splice sites have considerable homology among various genes, exact splice-site signals are unknown. Previously, applying the computer searching method to primary nucleotide sequences of various genes, we studied what kinds of patterns are the necessary and sufficient sequences for recognition of the 5'-slice site (donor site). We proposed that four common patterns, AG/GTA, /GTAAGT, RG/GTGAG, and AG/GTXXGT, where R = A or G and X = A, T, G, or C, are often used as such signals. In the present paper, we examined a number of experimental results on site-specific mutagenesis around donor sites and on alpha- and beta-thalassemia in globin genes, and found that the above four common patterns could explain almost all of those results.

Adenoviridae↗
PubMed1985

Primary myxedema with thyrotrophin-binding inhibitor immunoglobulins. Clinical and laboratory findings in 15 patients.

In a screening of 43 patients with primary myxedema, 9 patients were found to have IgG that inhibits the binding of 125I-thyrotrophin to its receptor (thyrotrophin-binding inhibitor immunoglobulins). Preparations of IgG from these patients did not stimulate thyroidal cyclic adenosine monophosphate generation and blocked thyroid stimulation by thyrotrophin in vitro. Clinical and laboratory features of 15 patients with this inhibitor, including 6 who were previously known, were compared with those of patients without the inhibitor. The patients with inhibitor, 2 men and 13 women, had onset of their hypothyroidism from age 2 to 49 years, and thyroid uptake in these patients was significantly lower than that in patients without inhibitor. Transient hypothyroidism was seen in all 5 infants born to 4 mothers having potent inhibitor immunoglobulins. These clinical findings indicate that thyrotrophin-receptor-blocking antibodies play a pathogenic role in a group of patients with primary myxedema.

Adolescent↗
PubMed1985

Immunohistological phenotyping of thyroid infiltrating lymphocytes in Graves' disease and Hashimoto's thyroiditis.

Subsets of lymphocytes in the thyroid were immunophenotyped by their surface antigens in frozen tissues of Hashimoto's thyroiditis and Graves' disease. Using triple layer immunoperoxidase staining (IP), monoclonal antibodies (T3, Leu 3, T8, anti-Tac and Leu 7) were employed to detect markers of T cell subsets, activated T cells, and a natural killer associated antigen. B cells were identified by 2 step IP with anti-IgD antisera. Excluding those cells forming lymphoid follicles, the density of lymphocytes infiltrating between thyroid epithelial cells was much higher in Hashimoto's thyroiditis than in Graves' disease. However, relative proportions of subsets were similar in both diseases. Most of the infiltrating cells were T3 positive T cells (T3+), with more T8+ (suppressor/cytotoxic T) than Leu 3+ (inducer/helper T). Some Leu 7+ were occasionally seen, but surface IgD positive mature B cells (IgD+) were almost absent. In contrast, IgD+ cells were densely aggregated in primary lymphoid follicles and mantle zones of secondary follicles. In these regions, Leu 3+ cells were about twice as frequent as T8+ cells. Some Leu 7+ and scarce Tac+ cells were also found. The present study indicates a major involvement of immunoregulatory T cells in autoimmune thyroid disease, and also suggested intrathyroidal maturation of B cells.

Adult↗
PubMed1985

[Clinical studies on the effectiveness of SM-4300, a new non-modified gammaglobulin preparation suitable for intravenous use, in refractory infections].

Eighteen cases of various infections, mostly having severe underlying diseases and showing no or insufficient responses to antibacterial chemotherapy, were treated with additional intravenous drip infusion of SM-4300 (2.5 or 5 g, once a day, for 1-3 days). Eight of the cases were excluded from the assessment of the effectiveness, as they died too early, or as their fever was supposed to have been "tumor fever" retrospectively. SM-4300 was found to be effective in 2 out of 5 septicemia cases, in 3 pneumonia cases, including 1 complicated with septicemia, out of 4, and also in 1 patient with liver abscess, as well as in another of meningitis caused by Campylobacter fetus; i.e. the efficacy rate was estimated as 60% in total. Any side effects attributable to SM-4300 were observed in none of the 18 cases. These results obtained seem to endorse the usefulness of the preparation.

Adolescent↗
PubMed1984

Sequence analysis of the transcribed and 5' non-transcribed regions of the ribosomal RNA gene in Dictyostelium discoideum.

The nucleotide sequence of Dictyostelium discoideum rDNA extending over almost the entire transcribed region and a part of the 5' non-transcribed spacer region has been determined. Computer analysis revealed that there were several conserved sequences in the 17S, 5.8S and 26S coding regions when compared with the sequences at analogous positions in some eukaryotic rRNA genes. The data also showed that the D. discoideum rDNA contains several extra sequences, which have not been found in other eukaryotes' rDNAs , near the 3' terminus of the 17S coding region and the 5' terminus of the 26S coding region.

Animals↗
PubMed1984

Altered balance of immunoregulatory T lymphocyte subsets in autoimmune thyroid diseases.

Three monoclonal antibodies recognizing cell surface antigens of total peripheral (OKT3), helper/inducer (OKT4) and suppressor/cytotoxic (OKT8) T lymphocytes were used by an indirect immunofluorescence technique to enumerate peripheral T lymphocytes in 25 patients with Graves' disease (including 4 euthyroid Graves' patients), 16 patients with Hashimoto's thyroiditis and 22 normal controls. Total lymphocyte count and percentages of overall T and helper/inducer T cells among peripheral lymphocytes in these conditions showed no significant difference from those of the controls. Percentage of suppressor/cytotoxic T cells, however, was decreased in Graves' disease patients with or without hyperthyroidism. The ratio of helper/inducer T cells to suppressor/cytotoxic T cells was increased in Graves' disease population and slightly increased in hypothyroid Hashimoto's thyroiditis patients. The ratio correlated with the mitogenic response of peripheral mononuclear cells to phytohaemagglutinin, but not with the serum levels of thyroid hormones nor with the titres of thyroid autoantibodies. These findings are in accordance with the results of previous functional studies and indicate possible defects in suppressor T lymphocytes in autoimmune thyroid disease.

Adolescent↗
PubMed1984

Combined scintiscans in the diagnosis of thyroid carcinomas.

We correlated scintigraphy and histological findings in 40 cases of nodular goiter in which two or more kinds of scintigraphy were performed preoperatively. 201Tl scintigraphy for imaging thyroid carcinoma showed a diagnostic agreement of 80% for thyroid lesions and 82% for metastatic lesions in the cervical lymph nodes. These agreements were higher than with 99mTc-bleomycin scintigraphy. Thus, 201Tl scan can be used to evaluate 'cold' thyroid nodules and to visualize metastatic lesions. 201Tl scan was also found valuable as a diagnostic measure for local recurrence of thyroid carcinoma. However, there were a few false-positive and false-negative results.

Adenoma↗
PubMed1984

A new imaging agent for medullary carcinoma of the thyroid.

Thyroid scintigraphy, using 99mTc(V) dimercaptosuccinic acid, was performed in four patients with pathologically confirmed medullary thyroid carcinoma and elevated serum calcitonin values. Significant uptake of the tracer was found in the clinically palpable cervical tumor masses, metastatic sites, and residual tumor. This finding, probably specific for medullary thyroid carcinoma, could be of great use in the diagnosis and the surgical follow-up.

Adenocarcinoma↗