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Biomedical subjects

N Hamada

Publications and source records attributed to N Hamada.

At least 181 records · Page 10Linked to original sources
PubMed1989

Nuclear binding sites for reverse triiodothyronine in human placenta.

It has been generally believed that reverse triiodothyronine (reverse T3, rT3) is biologically inactive. Nevertheless the serum rT3 level is very high in fetal life, when the serum calcium level is higher than in the maternal. For this hypercalcemia in fetal life, there is no convincing evidence that any major calcium regulating hormone is responsible. And the assumption that rT3 may be concerned in active transport of calcium at placenta could be suggested. In this study nuclear protein was isolated from human placenta by extraction with 0.4M KCl buffer and binding studies utilizing radioactive rT3 were carried out. Scatchard analysis presented a curvilinear pattern, suggesting two classes of receptors: One with a association constant (Ka) of 1.14 X 10(8) M-1 and a limited capacity (Bmax) of 32.0 X 10(-15) mol/100 micrograms DNA and the other with Ka = 4.34 X 10(6) and Bmax = 454 X 10(-15). Its relative affinities for several thyroid hormone analogues were calculated. If the affinity for rT3 was assigned l, that for triiodothyronine would be 1/40, thyroxine: 1/63, Triiodothyroacetic acid: 1/18. Sulfhydryl agents affecting these binding characteristics were also studied. The Ka was not substantially changed but the Bmax was notably decreased by dithiothreitol (43%) and 2-mercaptoethanol (26%). In liver nuclei, the binding characteristics of rT3 receptor were analyzed for comparison. In this case only a single class of low affinity-high capacity rT3 binding site with a Ka of 6.69 X 10(6) was detected, a finding which was apparently different from those in placenta.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1989

[The dental anthropological study on the erupted mesiodens in the Paiwan tribe of Formosan aborigines].

Mesiodens is one supernumerary tooth which appears in upper intra-central incisors. This tooth was originally described by Bolk (1917) who proposed the term 'mesiodens'. We investigated the incidence of mesiodens for the Paiwan tribe of Formosan aborigines (9 tribes) living in the mountain area of Taiwan. We have been continued to research on these tribes as viewed from dental anthropology. The materials used in this study were plaster casts of 152 males and 238 females (dental age: IIIA or over). The samples of the Paiwan tribe were selected from the dental casts obtained at Taitung and Pingtung (Machia and Wutai) in southern Taiwan. The results were as follows: 1. The occurrence of the erupted mesiodens in the upper incisal region was five cases (3.3%) in males, but was none in females. This tendency of incidence was much the same as that of Japanese. 2. The mesiodens was of rudimentary form: four cases (80%) showed conical-shaped type and the rest case was the sort of incisor. 3. In the incidence of the erupted mesiodens, the Paiwan tribe showed significantly higher than Japanese.

Anthropology↗
PubMed1989

Diagnosis of thyroid mass due to intravenous digital subtraction angiography--does it play an important part in diagnosis of thyroid mass?

33 patients with thyroid mass were studied by intravenous digital subtraction angiography (IV-DSA), thyroid scintigraphy (TS), ultrasonography (US), and computed tomography (CT). The detective rate of lesion by each diagnostic imaging was as follows: IV-DSA 71%, TS 70%, US 94%, and CT 76%. US was the most excellent and most sensitive diagnostic imaging of both benign and malignant lesions. As regards the thyroid cancer by IV-DSA, malignant findings were heterogeneity, an irregular contour, and an unclear contour of tumor stain. Specific diagnostic rate of each imagings was as follows: IV-DSA 88%, TS 100%, US 86%, and CT 75%. US was not so good imaging of a specific diagnosis for the thyroid mass. As regards the thyroid mass, influence of the common carotid artery and the internal jugular vein were investigated by the degree of compression of both vessels on IV-DSA. However IV-DSA could not reveal tumor invasion to these vessels. We learned present the limit of diagnosis of the thyroid mass due to IV-DSA, because IV-DSA was unable to reveal to us exactly information of both a sensitive and a specific diagnosis. We, however, think that IV-DSA is a useful diagnostic imaging as a mapping study which reveals a coronal image of a relationship between the thyroid mass and the common carotid artery and/or the internal jugular vein in surgery.

Adult↗
PubMed1988

Correlation between plaque size and genetic variation of type 3 poliovirus from a vaccinate.

Vaccine strain derivatives could be serially isolated from the feces of a healthy infant for about 30 days after the second administration of a trivalent poliovirus vaccine. These were all identified as poliovirus type 3, and no other types were detected. The titer in feces increased gradually until day 19, when it reached a maximum, after which it decreased. The plaque size altered roughly in parallel with the changes in the titer. On day 11 it began to increase, becoming the highest abruptly on day 15, and then fell again. Oligonucleotide mapping analysis of RNAs of isolated viruses showed that the samples from days 1 and 11 exhibited the same patterns as those shown by the vaccine strain RNA. However, on day 15 many of the preexisting spots had decreased, and new ones appeared. On day 27, the pattern was again similar to that of the original virus, rather than that of the day-15 virus. A nonmetric distance scaling and cluster analysis suggested that all the strains were derived from the same origin and that the polioviruses on days 1, 11, 21, and 27 had closer relationships, but the poliovirus on day 15 was different.

Feces↗
PubMed1988

Arterial patterns in the hand based on a three-dimensional analysis of 220 cadaver hands.

Three-dimensional analysis of 220 cadaveric hands to the submacroscopic level was done with clear stereoscopic arteriographs. The superficial palmar arch could be grouped into complete (96.4%) and incomplete (3.6%) arches. The complete arch was divided into four types on the basis of the terminal formation of the deep palmar arch. In the deep palmar arch, the complete arch was seen in 76.9% of the hands. This rate was smaller than that in other reports. The second dorsal metacarpal artery was seen in 92%. With regard to formation of the deep palmar arch, half of all the cases exhibited collateral pathways for the palmar side from the dorsum, sometimes the main arterial source of the deep palmar arch. The blood supply of the thumb comes mainly from the princeps pollicis artery, the terminal branch of the superficial palmar arch, and the first dorsal metacarpal artery, which originates from the radial artery or from different combinations of these arteries. The arteries of the thumb are classified by their anatomic course. The princeps pollicis artery (first palmar metacarpal artery) was absent in 2.4%.

Aged↗
PubMed1988

Hyperthermic effects on DNA repair of UV-irradiated Dictyostelium discoideum.

DNA repair of a lower eukaryote, Dictyostelium discoideum, has been investigated through the analysis of heat effects on cell mortality and DNA repair of UV-irradiated amoeboid cells. In a wild-type strain (NC4), an increase in temperature immediately after UV irradiation resulted in an increase in cell mortality, though similar heat treatment before UV irradiation had no such effect. Similar results were obtained in another wild-type strain, HPS83. In NC4, heat treatment after UV irradiation did not inhibit the nicking of DNA strands during excision repair processes, but did inhibit the rejoining of the DNA strand breaks. Removal of thymine-containing pyrimidine dimers from DNA molecules was also depressed by heat treatment after UV irradiation. In contrast, heat treatment before UV irradiation had no effect on any stage of the nicking process, the excision of the dimers or the rejoining. On the other hand, a radiation-sensitive mutant (TW8) defective in an incision step of the excision repair process did not show an increase in cell mortality in response to heat treatment administered either before or after UV irradiation. Though the optimum temperature for cell growth of the amoebae was 23 degrees C, the critical temperature for effective enhancement of cell killing was ca. 30 degrees C. Hence we assume that the excision repair of UV-damaged DNA is selectively sensitive to heat treatment.

Centrifugation, Density Gradient↗
PubMed1988

Monitoring of 131I in milk and rain water in Japan following the reactor accident at Chernobyl and estimates of human thyroidal dose equivalents.

Iodine-131 in milk and in rain water in Nagoya, Japan, (a location 8,000 km from Chernobyl) was monitored between May and July 1986. The 131I concentration in rain water ranged from 43.1 Bq L-1 on 4 May to 15 mBq L-1 on 12 July, and that in milk ranged from 21.8 Bq L-1 on 19 May to 11 mBq L-1 on 14 July. Iodine-131 concentrations in milk were estimated to be 4 to 6 times greater than those in rain water during the first few weeks after the accident. Both concentrations decreased with approximately the same effective half-life of 5.9 +/- 0.3 d for rain water and 5.0 +/- 0.2 d for milk. The 131I concentration in milk sold in markets varied from dairy to dairy and ranged from 0.07 to 0.2 times that in fresh milk. The maximum thyroidal dose equivalents estimated for an adult man and for a baby were far lower than the population annual dose equivalent to the thyroid from natural radiation.

Accidents↗
PubMed1988

Characterization of the thyroid microsomal antigen, and its relationship to thyroid peroxidase, using monoclonal antibodies.

MAb directed to the thyroid microsomal antigen have been developed. All bound to 101- and 107-kD bands in Western blot analysis using thyroid microsomal fraction as antigen. The MAb also bound to microsomal proteins immunoprecipitated by serum from patients having a high titer of anti-microsomal antibody but no antibodies to thyroglobulin or thyrotropin-stimulating hormone receptor. The pattern of binding was related to the amount of reducing agent. The 101- and 107-kD bands were increased by addition of dithiothreitol whereas, in its absence, numerous bands of higher molecular weight were present, suggesting a multimeric protein structure. Despite the inability to immunoprecipitate thyroid peroxidase (TPO) enzymatic activity, the MAb bound intensively in Western blot to denatured purified hog TPO and to denatured immunopurified human TPO. Trypsin digestion of the 101-107-kD antigen produced a doublet of 84-88 kD that was still immunoreactive with MAb. One of five polyclonal sera tested (with a microsomal antibody titer greater than 1/20,480 measured by the tanned red cell hemagglutination technique) also recognized the 84-88 kD trypsin fragments. Addition of V8 protease led to a disappearance of the 107-kD protein, but not the 101-kD protein, proving that this antigen is formed by two different polypeptides. The MAb bound strongly to thyroid epithelium, whereas binding to papillary carcinoma was absent or low and moderate for follicular and Hurthle cell carcinoma. This study indicates that the thyroid microsomal antigen and TPO are identical and are constituted of two different polypeptides. On SDS-PAGE the antigen appears as two contiguous bands which share common epitopes but are not identical, as proven by their size and difference in susceptibility to proteolytic digestion. The immunoreactivity of the molecule is highly dependent on a trypsin-sensitive site, which appears important in the recognition of the antigen by polyclonal sera and may have biological importance. The expression of microsomal antigenicity is variable among various thyroid carcinomas.

Antibodies, Monoclonal↗
PubMed1988

[Management of personnel exposure data with a personal computer].

This paper describes a software package that manages dosimeter inventory and exposure data with a personal computer. The computer, connected with the access control system, deals with both records of the film badge (FB) supply to workers and the ordering of new FB for a company, processes exposure data and produces reports. The software not only ensures accurate reports but also significantly reduces the tedious labour involved in managing the control system.

Computer Systems↗
PubMed1988

[Management of radioactive wastes using a personal computer].

This paper describes a software package for a personal computer which deals with storage records of radioactive wastes; the software keeps the records of purchase and use of radioisotopes and makes the inventory records of radioactive wastes. The records for the cargo booking of the wastes for the Japanese Radioisotope Association can be prepared by this software package.

Microcomputers↗
PubMed1987

Characterization and isolation of thyroid microsomal antigen.

We investigated the structure of the 107-kD thyroid protein recognized as microsomal antigen. Solubilized microsomes were incubated with affinity gels consisting of IgG, from thyroiditis patients or controls, linked to Reacti-gel. Eluates were analyzed by SDS polyacrylamide electrophoresis and Western blot. 107- and 101-kD proteins were augmented in eluates from gels containing patient IgG and had microsomal antigenicity. In a Western blot of microsomes run under unreduced conditions, poorly defined large proteins were identified by antibody. When eluted electrophoretically and reanalyzed in reducing conditions, they demonstrated the 107-kD antigen. The 107-kD protein identified in reducing conditions was extracted and reanalyzed under nonreducing conditions. Large molecular mass proteins were then observed. On two-dimensional electrophoresis, a 107-kD antigen was isolated with isoelectric point of 7.0. The microsomal antigen may be complexes or multimers of a 107-kD peptide with isoelectric point of 7.0.

Antigens↗
PubMed1987

Antibodies against denatured and reduced thyroid microsomal antigen in autoimmune thyroid disease.

Different antigenic determinants on thyroid microsomal antigen (MAg) could induce different antibodies, which, in turn, could have differing importance in the pathogenesis of autoimmune thyroid disease. In this study we demonstrated three types of microsomal antibodies (MAbs) present in serum of patients with autoimmune thyroid disease by Western blot analysis. These MAbs reacted with native, denatured, and denatured and reduced MAg. Methods for detecting the MAbs were developed, and the clinical significance of these Abs was analyzed in 197 patients with thyroid disorders. For measurement of Ab against native and denatured MAg, an enzyme-linked immunosorbent assay, in which wells were coated with untreated or sodium dodecyl sulfate-denatured MAg, was used. For measurement of Ab against denatured and reduced MAg, 6% SDS-polyacrylamide gel electrophoresis followed by Western blot analysis was used. Native MAb enzyme-linked immunosorbent assay values correlated highly with microsomal hemagglutination titers, but patients with high titers of Ab against native MAg did not necessarily have Ab against denatured MAg or reduced MAg. Abs against denatured MAg or denatured and reduced MAg were found in patients with Hashimoto's disease (28.8% and 13.6%) and Graves' disease (22.4% and 11.2%). The percentage of patients with positive denatured and reduced MAb was higher in Graves' disease patients who had a longer sick interval or who developed hypothyroidism after radioiodine treatment. This study provides the first clear demonstration that MAbs are heterogeneous. The data suggest that antibodies against denatured or denatured and reduced MAg may be related to destruction of the thyroid gland.

Autoantibodies↗
PubMed1987

Retrospective reevaluation of the significance of thyroid microsomal antibody in the treatment of Graves' disease.

The results of treatment were analyzed in relation to serum microsomal antibody (MCAb) titre before treatment in 1185 patients with Graves' disease. The percentage of patients who had ablative therapy because of poor response to antithyroid drug treatment was significantly greater in those with MCAb haemagglutination test (MCHA) titres greater than 1:25,000. With 131I treatment, the patients with MCHA titres greater than 1:6400 responded significantly less to therapy, although the analysis was done in 146 selected patients with certain defined radiation doses and small goitres. With surgical treatment, the percentage of the patients entering into remission was significantly smaller for patients with MCHA titres greater than 1:25,000, because of an increase in both hypothyroidism and relapses. The incidence of hypothyroidism was significantly higher in patients with marked lymphocyte infiltration and/or lymphoid follicles. The degree of these histological findings in Graves' disease was not marked in spite of high MCAb titre and it was significantly different from that in Hashimoto's disease when analyzed in relation to the MCHA titre. These data indicate that in Graves' patients with high MCAb titre, remission is difficult to obtain by treatment, and suggest that the significance of MCAb is different in Graves' disease and Hashimoto's disease. The titre in Graves' disease may be one expression of the activity of this disease.

Adolescent↗