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Biomedical subjects

Y Iida

Publications and source records attributed to Y Iida.

At least 235 records · Page 13Linked to original sources
PubMed1988

Sensitive, practical bioassay of thyrotropin, with use of FRTL-5 thyroid cells and magnetizable solid-phase-bound antibodies.

We have developed a new method for assessing the bioactivity of thyrotropin (TSH) in human serum by measuring cAMP production in FRTL-5 thyroid cells as an index of stimulation. To eliminate serum inhibitors of the cAMP response to TSH, we purified samples by mixing them with anti-TSH antibodies coupled to magnetizable particles. This method of immunoaffinity purification was simple and suitable for the measurement of a large number of samples. The detection limit of the bioassay was 3.13 milli-int. units of human TSH per liter. Intra-assay and interassay coefficients of variation ranged from 5.4 to 8.6% and from 12.6 to 21.5%, respectively. The concentrations of bioassayable TSH closely correlated with those of immunoassayable TSH, both in the immunoaffinity-purified samples (r = 0.946, P less than 0.001) and in the serum samples (r = 0.945, P less than 0.001) from 14 euthyroid subjects and 53 hypothyroid patients with Hashimoto's thyroiditis. The bioactivity-to-immunoactivity ratio was almost constant (0.84 +/- 0.30; mean +/- SD) over the range of concentrations of immunoassayable TSH in serum, 6.3 to 177 milli-int. units/L. We also demonstrate that the technique is applicable to measurements of bioactivities of circulating forms of immunoreactive TSH in different pathophysiological conditions.

Animals↗
PubMed1987

Activity of blood coagulation factor XIII as a prognostic indicator in patients with Henoch-Schönlein purpura. Efficacy of factor XIII substitution.

UNLABELLED: Determination of coagulation Factor XIII (F XIII)-related parameters in 21 patients with Henoch-Schönlein purpura documented a significant decrease of F XIII activity as well as of the F XIII-related antigenic determinants. Subgroup analysis with regard to the clinical symptoms showed an even further decrease of these parameters in patients with gastrointestinal complications. Stimulated by these findings a substitution therapy with a F XIII concentrate was initiated in those patients whose F XIII activity in plasma remained low and who developed severe abdominal pain accompanied by persisting gastrointestinal bleeding. This therapeutic approach not only corrected the laboratory data, but more important led to a cessation of pain and bleeding. A rapid decrease of F XIII levels after transfusion below 40 U/ml was indicative of relapse of abdominal symptoms, while increasing values were associated with the recovery of the patients. IN CONCLUSION: F XIII activity determinations appear to have a predictive value in patients with Henoch-Schönlein purpura, and the administration of F XIII concentrates may contribute to the improvement of gastrointestinal complications.

Child↗
PubMed1987

Characterization of photoreceptor cell differentiation in the rat retinal cell culture.

Photoreceptor cell differentiation in the rat retina was studied in vivo and in vitro, using an immunohistochemical method to demonstrate opsin-like immunoreactivity. Cells in a dissociated monolayer culture expressed some properties characteristic of rat rod cells developing in vivo, including a ciliary structure and opsin-like immunoreactivity. Immunoblot analysis revealed that cultured retinal cells synthesize a polypeptide with the same molecular weight as that synthesized by the intact retina. Although the outer segment (OS) was not present in the culture, immunoreactive cells possessed a ciliary structure. Opsin-like immunoreactivity was found on the plasma membrane, including the cilia. The neuritic extensions were also intensely stained. In mature rod cells of the intact rat retina, opsin was detected only on the OS but, during development, it was found both in the somatic region of the rod cells and on the differentiating OS. During maturation of rod cells opsin immunoreactivity seemed to shift to the OS from other locations. However, some "displaced" photoreceptor cells, found in the inner nuclear layer and extending fibers bipolarly, retained immunoreactivity throughout their structure. The absence of polarized distribution of opsin in these cells is considered to be due to an abnormal environment, which may also be the case with cultured retinal cells. The present culture conditions will offer a useful model system to understand the cellular mechanism of the hereditary retinal dystrophy of rodent animals in which photoreceptor cells selectively degenerate.

Animals↗
PubMed1987

Phylogenetic relationships between adenoviruses as inferred from nucleotide sequences of inverted terminal repeats.

The nucleotide (nt) sequences of inverted terminal repeats (ITR) from human adenovirus (Ad) 19, bovine Ad1 (BAd1), bovine Ad3 (BAd3), canine Ad2 (CAd2) and an avian Ad, EDS-76, were determined. The length of the ITR sequence was 160 bp in Ad19, 159 bp in BAd1, 195 bp in BAd3, 196 bp in CAd2 and 52 bp in EDS-76. CAd2 had the longest ITR among the examined Ads, BAd3 the second longest, and EDS-76 had the shortest ITR. A TAAT sequence located between the 10th and 13th nt counted from the ends was conserved in all Ads examined so far. To determine phylogenetic relationships among human and animal Ads, sequences of their ITRs were compared, and a phylogenetic tree was constructed by using the maximum-likelihood method. It is the method involving statistical analysis of computing the probability of a particular set of sequences on a given tree and maximizing this probability over all evolutionary trees [Felsenstein, J. Mol. Evol. 17 (1981) 368-376]. From these analyses, it was found that members belonging to the same human Ad subgenus are related closely to each other, whereas representatives of different human subgenera are distributed rather divergently among animal Ads.

Adenoviridae↗
PubMed1987

Syntactic pattern analysis of 5'-splice site sequences of mRNA precursors in higher eukaryote genes.

The signals which direct the excision of introns from eukaryotic pre-mRNA are not yet well understood. In order to define the signals for 5'-splice sites of mRNA splicing, nucleotide sequences including 5'-splice junctions of mammalian pre-mRNAs are analysed by means of syntactic pattern analysis. Taking this approach, we infer the grammatical rules which specify 5'-splice sites and construct a finite automaton which is the recognizer of the nucleotide sequences at 5'-splice sites. By scanning the automaton along nucleotide sequences, we can identify the positions of 5'-splice junctions with a degree of discrimination of up to 94-97% in the known genes, while the degree of prediction is in the range 50-55% in new genes.

Algorithms↗
PubMed1987

Thyroid gland: MR imaging.

Magnetic resonance (MR) imaging was performed in eight healthy volunteers and 30 patients with histologically and endocrinologically proved thyroid diseases. The use of a surface coil greatly improved spatial resolution, and normal anatomic structures were well demonstrated. In thyroid tumors, the margin, pseudocapsule, and lymph nodes were easily detected. Smooth margins, lobulated margins, and pseudocapsules were found in both adenoma and papillary carcinoma, whereas unclear margins were found only in papillary carcinoma. An unclear margin between the tumor and adjacent normal thyroid tissue seemed to reflect an ill-defined tumor border on gross pathologic examination. Metastatic lymph nodes as small as 3 mm were seen. Identification of small vessels enabled detection of dilated vessels in thyroid parenchyma in patients with Graves disease. Hemorrhage (hemorrhagic degeneration) was often found in adenoma, papillary carcinoma, and adenomatous goiter, resulting in variable signal intensity.

Adenoma↗
PubMed1987

Rupture of an aneurysm of the aortic sinus of Valsalva into the right ventricle. A case presenting an unusual hemodynamic manifestation.

Rupture of an aneurysm of the aortic sinus of Valsalva into the right ventricle is described. Surgery revealed a small aneurysm ruptured into the right ventricle near the tricuspid valve without aneurysmal involvement of the tricuspid valve. The cineangiogram revealed a shunt from the aortic sinus into the right atrium not during systole but during diastole, and increased oxygen saturation was found in the right atrium. The unusual hemodynamics in this case was most probably due to the closure of the small aneurysmal opening due to myocardial contraction during systole, so that the shunt flow through the aneurysmal tract occurred only during diastole and was directed toward the right atrium due to the location of the aneurysm. Thus, even without aneurysmal involvement of the tricuspid valve or tricuspid regurgitation, the oxygen saturation increased in the right atrium.

Adult↗
PubMed1987

Stabilization, partial purification, and characterization of thyrotropin receptors in solubilized guinea pig fat cell membranes.

Specimens obtained during the course of efforts to purify the TSH receptor in guinea pig fat cell membranes solubilized with Triton X-100 displayed extensive loss of TSH binding activity, analogous to that seen by others during the purification of the TSH receptor in thyroid membranes. Therefore, as a preliminary to efforts to purify the TSH receptor in solubilized fat cell membranes (SFCM), experiments were undertaken to ascertain the factors responsible for this loss of binding activity and to find means for its prevention. Temperature proved to be the most important variable. SFCM stored at -70 C retained their activity with respect to the binding of bovine TSH (bTSH) for months, but binding activity was rapidly lost during storage of SFCM at 4 C, a loss due to a decrease in receptor number rather than binding affinity. Loss of binding activity during storage of SFCM at 4 C was unaffected by the addition of 1 mM cystine and was only slightly and temporarily retarded by a mixture of three protease inhibitors (phenylmethylsulfonyl fluoride, aprotinin, and leupeptin). These results indicated that loss of TSH receptors during storage at 4 C is not due to reduction of disulfide bonds or to proteolytic degradation. On the other hand, activity of the receptor was largely or entirely preserved during at least a week of storage at 4 C by the formation of a TSH-TSH receptor complex, by the addition of 40-50% glycerol either during solubilization or immediately thereafter, or by lyophilization immediately after solubilization. Receptors preserved by these three measures retained their original affinity for bTSH and their response to the TSH binding inhibitory activity of Graves'-immunoglobulin G. In the light of these results, SFCM were prepared in 40% glycerol and then subjected to TSH-affinity gel chromatography. The resulting materials contained at least 29.3% of the original binding activity, and their specific TSH binding activity was increased 227-fold. Saturation analysis of [125I]bTSH binding to this preparation revealed an association constant (Ka) (2.2 x 10(9) M-1), very similar to that in the original SFCM preparation. Binding of [125I]bTSH was inhibited in a dose-dependent manner by Graves'-immunoglobulin G, and in multiple preparations of the latter, TSH binding inhibitory activity measured in the affinity-purified receptor preparation was closely correlated with that measured in SFCM.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1987

Inhibition of thyrotropin-induced growth of rat thyroid cells, FRTL-5, by immunoglobulin G from patients with primary myxedema.

We studied thyroid growth-blocking activity in immunoglobulin G (IgG) fractions of serum from 24 patients with primary myxedema, 24 patients with goitrous Hashimoto's thyroiditis, and 18 normal subjects by measuring the ability of their IgG to inhibit TSH-induced [3H]thymidine incorporation into DNA in a rat thyroid cell line, FRTL-5. Both groups of patients were receiving T4 when studied. [3H]Thymidine incorporation induced by 0.1 mU/ml bovine TSH was significantly inhibited by the addition of 2 mg/ml IgG from patients with primary myxedema (P less than 0.01), while it was not affected by IgG from the normal subjects or 23 of the 24 patients with goitrous Hashimoto's thyroiditis. IgG from patients with primary myxedema also inhibited the [3H]thymidine incorporation induced by Graves' IgG, but not that induced by forskolin, cholera toxin, (Bu)2cAMP or phorbol-12-myristate-13-acetate. The inhibition of TSH-induced [3H]thymidine incorporation by IgGs from patients with primary myxedema was significantly correlated with their inhibitory activities against both TSH-induced cAMP generation and TSH binding (P less than 0.001). These data indicate that these growth-blocking antibodies are directed against the TSH receptor and might be one of the causes of the thyroid atrophy in patients with primary myxedema.

Adolescent↗
PubMed1987

The mechanism of spontaneous hypothyroidism in patients with Graves' disease after antithyroid drug treatment.

The natural course of Graves' disease results in hypothyroidism in up to 20% of patients previously treated with antithyroid drugs. The precise mechanisms are not known, although autoimmune destruction of thyroid tissue has been proposed. We studied sequentially obtained serum samples from three patients with hyperthyroid Graves' disease previously treated with an antithyroid drug who became hypothyroid to determine possible causes of their hypothyroidism. Antithyroglobulin and antithyroid microsomal autoantibodies, TSH binding inhibitory immunoglobulin (TBII), thyroid-stimulating antibody (TSAb), and thyroid stimulation-blocking activity were measured. Autoantibodies were markedly elevated throughout the clinical course in all three patients. Patient 1 had no TBII and blocking activity and extremely high TSAb when she was euthyroid as well as hypothyroid. Hypothyroidism was probably the result of autoimmune thyroid destruction. In patient 2, TSAb disappeared, and TBII and blocking activity increased markedly when she developed hypothyroidism, which thus appeared to result from blocking antibodies. Patient 3 had intermittent periods of hyper- and hypothyroidism before becoming and remaining euthyroid. While initially hypothyroid, TBII was weakly positive, and TSAb was strongly positive; subsequently, when hyperthyroidism recurred, TBII and TSAb were strongly positive. Hypothyroidism appeared to result from focal autoimmune thyroiditis. Patients with hyperthyroid Graves' disease may develop hypothyroidism later by different means. Autoimmune thyroiditis, diffuse or focal, with thyroid destruction is one mechanism. The appearance of antibodies that block TSH stimulation may be another.

Adult↗
PubMed1987

Optimization and clinical assessment of a radioreceptor assay for thyrotropin-binding inhibitor immunoglobulins.

We tried to improve the sensitivity of a radioreceptor assay for thyrotropin-binding inhibitor immunoglobulins (TBII) by modifying assay conditions. About a twofold increase in sensitivity without a loss of reproducibility was obtained by prolonging the incubation of the receptors with test serum from 15 to 120 min before the addition of 125I-labeled thyrotropin. In 20 untreated, 49 treated patients with Graves' disease and 19 patients with euthyroid Graves' disease, TBII activities obtained using 120 min preincubation were significantly higher than those obtained using 15 min preincubation (p less than 0.005). No significant increase in TBII activities was observed in the presence of sera from patients with primary hypothyroidism (n = 17), simple goiter (n = 7), adenomatous goiter (n = 11), thyroid adenoma (n = 11) or cancer (n = 12). TBII were detectable in 15 (47%) of 32 triiodothyronine-nonsuppressible Graves' patients who were receiving maintenance antithyroid drug therapy using 120 min preincubation, while they were positive in only 6 patients (19%) using 15 min preincubation. The assay using a longer preincubation period was found to be sensitive, specific and useful for diagnosis and follow-up of Graves' disease.

Adenoma↗
PubMed1987

HLA-DR antigen expression on intrathyroidal lymphocytes and thyrocytes in Hashimoto's thyroiditis and Graves' disease: an immunohistological study.

In frozen sections of thyroid glands with Hashimoto's thyroiditis (HT) and Graves' disease (GD), infiltrating lymphocytes were tested for their expression of HLA-DR antigens as a marker of in situ activation. In a combination of indirect immunoperoxidase and direct immunofluorescence staining, most of the immunoglobulin D positive mature B cells were found to be DR positive (DR+) in both diseases. In HT, sizable portions of both helper/inducer T (Leu3+) and suppressor/cytotoxic T (Leu2+) cells were DR+ in interfollicular regions as well as in lymphocyte clusters and lymphoid follicles. In GD, the proportion of DR+ cells in the interfollicular Leu2+ population was significantly lower than that of HT. DR+ thyrocytes were seen in all 14 cases of HT and in 14 out of 16 cases of GD, especially in the vicinity of lymphocyte aggregates. The extent of their DR expression was not correlated with the percentage of DR+ cells in either T subset. These results indicate that a significant portion of infiltrating T cells are activated in autoimmune thyroid diseases, and there may be bidirectional interaction between DR+ thyrocytes and DR+ T cells. The difference in frequency of Leu2+ DR+ cells may account for the difference between the immunopathological features of HT and GD.

Adolescent↗