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Biomedical subjects

H Fukazawa

Publications and source records attributed to H Fukazawa.

At least 127 records · Page 7Linked to original sources
PubMed1987

Thyroid function and antimicrosomal antibody during the course of silent thyroiditis.

The thyroid function and antithyroidal antibody were studied in 17 patients with silent thyroiditis unrelated to pregnancy. The antimicrosomal hemagglutination antibody (MCHA) was negative in ten of them (group I) and was positive in seven (group II). At one month after the thyrotoxicosis, thyroid function became normal in both groups. At two months after the onset of thyrotoxicosis, in group I T4 (8.1 +/- 1.8 micrograms/dl, Mean +/- SD), T3 (113 +/- 25 ng/dl) and TSH were normal. At that time T4 (2.8 +/- 2.2 micrograms/dl) was significantly decreased (p less than 0.001) compared with those of group I and the levels of TSH were strikingly increased in 6 patients in group II. The level of T3 (96 +/- 29 ng/dl) in group II was not different from that of group I. Therefore MCHA was negative in patients who did not develop hypothyroidism and MCHA was positive in patients who developed hypothyroidism. The development of hypothyroidism two months after thyrotoxicosis and positive MCHA are correlated. The Tg was elevated in 7 out of 13 patients (54%) with negative antithyroglobulin hemagglutination antibody and in the remainder was normal during thyrotoxicosis. The discrepancy between the level of Tg and thyroid hormones was discussed.

Adult↗
PubMed1987

Antibody-dependent cell-mediated cytotoxicity against human eye muscle cells and orbital fibroblasts in Graves' ophthalmopathy--roles of class II MHC antigen expression and gamma-interferon action of effector and target cells.

We have studied the significance of antibody dependent cell-mediated cytotoxicity (ADCC) against human orbital fibroblasts (OF) and eye muscle (EM) cells in the pathogenesis of the orbital autoimmune reactions of Graves' ophthalmopathy (GO). Possible roles of Class II MHC antigen expression on the surface of orbital target cells and of gamma-interferon (gamma-IFN) modulation of ADCC were also studied. Both OF and EM expressed HLA-DR antigen when stimulated with gamma-IFN and phytohemagglutinin, but not spontaneously, and not by thyroid stimulating hormone or alpha-IFN. Intrathyroidal T cells from a patient with GO induced greater DR expression on both OF and EM cells than equal numbers of her peripheral blood T cells. gamma-IFN treated EM and OF were more susceptible to lysis in ADCC assays than untreated targets. gamma-IFN also enhanced lysis in ADCC assays by an effect on the killer cell population. On the other hand treatment with alpha-IFN, which is a potent inducer of Class I antigen expression, did not affect the susceptibility of target cells to lysis in ADCC. When sera from patients with GO were tested in ADCC, tests were positive (% specific lysis greater than mean + 2 s.d. for normals) in 10 of 20 patients with EM cells, but in only two of 25 with OF. The degree of killing of EM cells was significantly positively correlated to that of abdominal skeletal muscle cells and, to a lesser degree, normal thyroid cells, but not OF. In sera showing killing of EM cells and OF, ADCC activity against EM cells was absorbed by preincubation with EM and orbital connective tissue membranes but not thyroglobulin and, conversely, lysis of THY cells was absorbed by preincubation of positive sera on monolayers of THY and EM cells and OF, but not vascular endothelial (VE) cells. Finally, killing of 51Cr labelled EM cells was inhibited by addition of unlabelled ('cold') thyroid cells, EM cells and OF, but not VE cells. Our findings suggest that ADCC is likely to be an important mechanism for the eye muscle cell damage of GO, but not for the associated orbital connective tissue inflammation. Since ADCC is not MHC-restricted the enhanced lysis of HLA-DR positive target cells presumably reflects other effects of gamma-IFN treatment on both the killer cell population and the target cells.

Adolescent↗
PubMed1987

Cytotoxic mechanisms in autoimmune thyroid disorders and thyroid-associated ophthalmopathy.

Cytotoxic antibodies against thyroid cells and eye muscle cells, measured as antibody-dependent complement-mediated cytotoxicity and ADCC, have been demonstrated in sera from patients with Hashimoto's thyroiditis and thyroid-associated ophthalmopathy, respectively. Such antibodies are probably never present in the absence of target cell damage. Because cell-mediated cytotoxicity plays an important role in experimental autoimmune thyroiditis, further studies are necessary to elucidate the roles of NK cells, K cells, and cytotoxic T lymphocytes in the thyroid cell damage in AITD and orbital cell damage in ophthalmopathy. The socalled aberrant expression of HLA-DR antigens on thyroid cells and orbital cells and the gamma-interferon production by activated T cells may be both intimately associated with the development of autoimmune reactions in the thyroid and the orbit. Cytotoxic antibodies and cytotoxic T lymphocytes against antigens shared between eye muscle cells and thyroid cells may be directly responsible for the eye muscle cell damage in endocrine ophthalmopathy, and they may explain the close association of ophthalmopathy with Graves' hyperthyroidism and Hashimoto's thyroiditis.

Animals↗
PubMed1986

Involvement of leukocytes in the oxygenation and chlorination reaction of phenylbutazone.

A center carbon atom of 1,3-diketone moiety of phenylbutazone was oxidized to give three metabolites--4-hydroxyphenylbutazone (metabolite I), 4-hydroperoxyphenylbutazone (metabolite II) and 4-chlorophenylbutazone (metabolite III)--by the action of enzymes present in leukocyte extract obtained from peritoneal exudate of rats. Both metabolites II and III were produced by peroxidases, while metabolite I was produced by enzymes other than the peroxidases.

Animals↗
PubMed1986

Purification and characterization of human hepatic cysteine-conjugate beta-lyase.

Cysteine-conjugate beta-lyase (EC 4.4.1.13) was purified about 880-fold from human liver obtained post mortem. The purification procedure included (NH4)2SO4 precipitation, chromatography on DEAE-cellulose and hydroxyapatite, gel filtration on Sephadex G-200, and chromatofocusing. The purified enzyme cleaves the C-S bond of several S-aryl-L-cysteines to yield equimolar amounts of thiols, pyruvic acid and ammonia via an alpha beta-elimination reaction. The Mr of the enzyme was estimated to be 88,000 by gel filtration. The enzyme is thermolabile, has a pH optimum of 8.5, and an apparent Km of 0.7 mM towards S-(p-bromophenyl)-L-cysteine. The enzyme requires pyridoxal 5'-phosphate as a cofactor, and hence the enzyme activity was completely abolished by hydroxylamine. No effect of EDTA or thiol-blocking reagents was observed on the activity of the enzyme.

Carbon-Sulfur Lyases↗
PubMed1986

Effects of chincap force on the timing and amount of mandibular growth associated with anterior reversed occlusion (Class III malocclusion) during puberty.

The effects of chincap force on the amount and timing of mandibular growth associated with anterior reversed occlusion (Class III malocclusion) were studied during the pubertal period in 26 Japanese girls. Their records consisted of serial lateral cephalometric roentgenograms, wrist-hand roentgenograms, periodic data of standing height, and time records of chincap use. The stage of pubertal growth was first evaluated by the change of ossification events of hand bones and incremental change of standing height. Mandibular measurements were assessed on this maturational basis. The findings indicated that application of chincap force (500 to 600 g, average 11 to 12 hours per day) hardly alters the general pattern of mandibular growth timing at puberty. With regard to inhibition of growth amounts, the effects seem to take place independently in different parts of the mandible. The length of time of force application per day in the range from 6 to 15 hours did not have a significant role in the change of growth amount and/or timing in the clinical use of the chincap. Individual reactions to the chincap force varied in the effects on mandibular growth variables. Further study of the effects of retrusive orthopedic force on the mandible during the rapid growth phase of puberty is indicated.

Adolescent↗
PubMed1986

Effect of changes in thyroid state on metabolism of thyroxine by rat placenta.

We studied the effect of the state of the thyroid on T4 monodeiodination in the rat placenta, and it was compared with those in the liver and kidney. The tissues, maternal serum, and amniotic fluid were obtained from pregnant rats. The tissues were homogenized in cold 50 mM Tris-HCl buffer, pH 7.5. The homogenate (1 mg protein) was incubated at 37 degrees C for 60 min with 1 microgram T4 in the presence of 5 mM DTT. The T3 and reverse T3 generated in the reaction mixture were extracted into cold ethanol and measured by RIAs. The conversion of T4 to reverse T3 in rat placenta was not significantly changed in MMI-induced hypothyroidism or T4 induced hyperthyroidism. On the other hand, conversion of T4 to T3 in the liver and kidney were changed in parallel with the thyroid state. The concentration of reverse T3 in the amniotic fluid was increased in accordance with the increase in the maternal serum T4 concentration. These results indicate that the placental T4 inner ring deiodination is not affected by the thyroid state, and that the change in the amniotic fluid reverse T3 concentration in this study is mainly dependent upon the change in maternal thyroid function.

Amnion↗
PubMed1986

Free thyroxine estimation for the screening of hyper- and hypothyroidism in an adult population.

Serum free thyroxine (FT4), total T4 (T4) and total T3 (T3) were determined by radioimmunoassay in 1,114 adults during a periodic health evaluation to detect unsuspected thyroid dysfunction. As a result, 3 patients with hyperthyroidism, 4 with hypothyroidism, 3 taking thyroid medication, 4 with chronic thyroiditis, 1 with simple goiter and 3 women under estrogen administration were found. Free T4 values were within the normal limits in the present four subjects taking estrogens, but all of them showed high T4 and one high T3 values. FT4 and T4 were low in four patients with hypothyroidism, but two of them showed normal T3 values. For the screening of hyperthyroidism, FT4 was the most reliable measurement and determination of either FT4 or T4 was suitable for the screening of hypothyroidism, but T3 measurement did not diagnose all patients with hypothyroidism, but T3 measurement did not diagnose all patients with hypothyroidism.

Adult↗