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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 793 records · Page 44Linked to original sources
PubMed1991

Establishment and characterization of four myeloma cell lines which are responsive to interleukin-6 for their growth.

Four human myeloma cell lines (MM-S1, MM-A1, MM-Y1 and MM-C1) were established from patients in the terminal stage of multiple myeloma. All the cell lines were PCA-1 positive and three were CD38 (OKT10) positive. The class of cytoplasmic immunoglobulin in each of these cell lines was identical to that of the monoclonal protein detected in each patient. Epstein-Barr virus nuclear antigen was negative in all cell lines. An examination of the tritiated thymidine uptake showed that all four cell lines proliferated in response to interleukin-6 (IL-6), while MM-S1 also responded to IL-5. Immunological staining with an anti-IL-6 receptor monoclonal antibody revealed the presence of receptors for IL-6 on the cells from each cell line. Three of them formed colonies dependent on IL-6 in methylcellulose semi-solid culture. All four cell lines grew better when human plasma was added as a supplement to the culture in comparison to fetal calf serum. Northern blot analysis showed that the three cell lines tested did not express IL-6 messenger RNA. These results indicate that these four cell lines are responsive to IL-6, but not by an autocrine mechanism, at least in the three lines examined.

Adult↗
PubMed1990

Structures of the asparagine-linked oligosaccharides of guinea-pig factor B of the alternative complement pathway.

This paper describes the structures of the asparagine-linked oligosaccharides of two forms of guinea-pig Factor B of the alternative complement pathway with different Mr values. Oligosaccharides were quantitatively liberated from both glycoproteins by hydrazinolysis, fractionated by paper electrophoresis and Bio-Gel P-4 column chromatography, and their structures determined by sequential exoglycosidase digestions in conjunction with methylation analysis. Both glycoproteins were shown to have the same biantennary complex-type oligosaccharides but it is suggested that they contain different numbers of oligosaccharide chains.

Animals↗
PubMed1990

[Erythrocyte sorbitol levels in patients with thyrotoxicosis].

Hyperglycemia and impaired glucose tolerance are frequently observed in patients with hyperthyroidism. However, little is known about whether altered polyol metabolism in hyperthyroidism is present or not. To examine changes in polyol metabolism in hyperthyroidism, we investigated changes in erythrocyte sorbitol, glyceraldehyde reductase (GAR) and sorbitol dehydrogenase (SDH) activities during hyperthyroid and euthyroid states in patients with thyrotoxicosis. Mean levels of erythrocyte sorbitol and GAR were 32.0 +/- 1.6nM/g.Hb and 147.1 +/- 0.3mU/g.Hb, respectively. In thyrotoxic patients in a hyperthyroid state, these values were significantly higher than those in euthyroid controls. Mean level of erythrocyte SDH in thyrotoxic patients was weak but was significantly increased in comparison with that of euthyroid controls. However, mean levels of erythrocyte sorbitol and GAR were remarkably reduced to 23.6 +/- 1.4nM/g.Hb and 125.3 +/- 4.6mU/g.Hb in thyrotoxic patients in a euthyroid state after treatment with anti-thyroid drugs or by subtotal thyroidectomy. Mean level of SDH, on the other hand, was increased after the treatment. In addition, positive correlations were observed between the level of erythrocyte sorbitol or GAR, and the level of free thyroxine(FT4) or free triiodothyronine(FT3). A negative correlation was observed between the level of erythrocyte SDH and the level of FT4 or FT3. These results suggest that the level of erythrocyte sorbitol may be increased through direct acceleration of erythrocyte GAR activity by increased thyroid hormone levels in patients with thyrotoxicosis.

Adult↗
PubMed1990

HRF20, a membrane inhibitor of complement attack, does not protect cells from the cytotoxic reaction by lymphokine activated killer cells.

HRF20, a 20 kDa homologous restriction factor, is a membrane glycoprotein anchored via galactosyl phosphatidyl inositol. Its function is to protect cells from attack by homologous complement. Adsorption of purified HRF20 to Raji cells which have little, if any, of this factor increased their resistance to cytolysis by homologous complement. However, the same cells treated with HRF20 remained sensitive to cytotoxic attack by IL-2 activated lymphocytes (lymphokine activated killer cells; LAK cells). Since LAK cells are effector cells which release perforin, HRF20 does not appear to protect cells from the damage caused by perforin.

Antibodies, Monoclonal↗
PubMed1990

Inhibitory effect of a new androstenedione derivative, 14 alpha-hydroxy-4-androstene-3,6,17-trione (14 alpha-OHAT) on aromatase activity of human uterine tumors.

The development of human uterine estrogen-dependent tumors is considered to be closely related to estrogen biosynthesis. This study examined whether or not 14 alpha-hydroxy-4-androstene-3,6,17-trione (14 alpha-OHAT), a new 4-androstene-3, 17-dione derivative synthesized microbiologically, inhibits estrogen biosynthetase (aromatase) activities of human uterine tumors (i.e. uterine endometrial cancer, uterine leiomyoma and uterine adenomyosis tissues). 14 alpha-OHAT inhibited aromatase activity in all uterine tumors, dose-dependently (0.1-10 microM). Moreover, 14 alpha-OHAT did not show the binding affinity to rabbit uterine cytosol-sex steroids, and it was not converted to estrogen in human placental preparations. Thus, 14 alpha-OHAT, an aromatase inhibitor, may be useful clinically as an endocrine chemotherapy for peri- or post-menopausal women with uterine estrogen-dependent tumors.

Adult↗
PubMed1990

[Changes in TSH-receptor antibody (TR-AB) and thyroid stimulating antibody (TS-AB) after thyroidectomy in thyrotoxic patients].

Changes in TSH-receptor antibody (TR-Ab) and thyroid stimulating antibody (TS-Ab) after thyroidectomy were examined in seventeen thyrotoxic patients (3 males and 14 females, 40.0 +/- 3.4 yr) with positive TR-Ab and TS-Ab. They were subjected to thyroid surgery because of suspected malignancy, methymazol induced agranulocytosis, cardiac failure, recurrent gastric ulcer or emotional instability. Of these patients, 3 were totally thyroidectomized, 11 were subtotally thyroidectomized and 3 were unilaterally lobectomized. Histological findings in these patients showed diffuse hyperplasia in 8 cases, an adenomatous goiter in 3, diffuse hyperplasia plus follicular adenomas in 5, and Hashitoxicosis in one. Their thyroid function before surgery was as follows: T3 level, 3.9 +/- 0.7 ng/ml; T4, 19.5 +/- 3.3 micrograms/dl; free T3, 11.9 +/- 1.2 pg/ml; free T4, 4.9 +/- 1.0 ng/dl; and TSH, 0.9 +/- 0.1 microU/ml. Mean levels of TR-Ab and TS-Ab before surgery were 56.8 +/- 4.6% and 1,218.6 +/- 262.4%, respectively. Positive anti-thyroid antibody (TGHA) was 47.0%, positive anti-microsomal antibody (MCHA) was 88.2% in these thyrotoxic patients, and mean levels of TGHA and MCHA were 1,688 +/- 715 and 89,280 +/- 34,717 times, respectively. After the operation, these parameters were decreased and their thyroid functions became an euthyroid or a hypothyroid state one month later. The incidence of post-operative hypothyroidism was 45.5% in subtotally thyroidectomized patients, 33.3% in unilaterally lobectomized patients and 100% in totally thyroidectomized patients. TR-Ab levels decreased from 56.2 +/- 6.5% before surgery to 24.5 +/- 12.2% 12 months after surgery, but increased again to 35.0 +/- 15.7% 24 months after surgery in subtotally thyroidectomized patients. These levels also decreased from 50.4 +/- 11.0% before surgery to 37.8 +/- 11.4% 12 months after surgery, and remained unchanged to 38.2 +/- 10.4% 24 months after surgery in unilaterally lobectomized patients. On the other hand, in totally thyroidectomized patients, TR-Ab levels decreased and normalized 12 months after surgery. One of subtotally thyroidectomized or unilaterally lobectomized patients developed recurrent thyrotoxicosis with an increased positive TR-Ab. Mean levels of TS-Ab decreased to 28.3 +/- 181.3% and 152.5 +/- 47.9% 12 and 24 months after surgery, respectively, in subtotally thyroidectomized patients. These levels decreased 12 months after surgery and then increased again to 303.6 +/- 130.6% in unilaterally lobectomized patients. On the other hand, TS-Ab levels decreased and normalized to 94.3 +/- 3.9% 6 months after surgery in totally thyroidectomized patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Electrostatic and redox potential effects on the rat of electron-transfer reaction of nicotinamide adenine dinucleotides with 1-substituted 5-ethylphenazines.

The effects of redox potential and electric charge on the rate of electron-transfer reaction by a two-electron process were investigated. For electron donors, beta-NADH, beta-NADPH and alpha-NADH were used; they have similar structures but different charges and different redox potentials. For electron acceptors, the following 5-ethylphenazine derivatives were used: 1-(3-carboxypropyloxy)-5-ethylphenazine, 1-(3-ethoxycarbonylpropyloxy)-5-ethylphenazine, and 1-[N-(2-aminoethyl)carbamoylpropyloxy]-5-ethylphenazine. They have similar structures and different charges. Using these donors and acceptors, the potential and the charge effects were estimated separately. In the potential effect, a linear free energy relationship was observed for the change in the redox potential of the donor with a Brønsted slope of about unity. On the other hand, the slope for the change in the potential of the acceptor was about 0.5. These results show that the potential effect due to electron donors is different from that due to electron acceptors. A linear relationship was also observed between activation free energy and electrostatic force (or potential). The redox potential effect and the electrostatic effect are independent and additive. New theory for the mechanism of electron-transfer reactions is needed to explain these results.

Electricity↗
PubMed1990

Genomic DNA structure of two new horseradish-peroxidase-encoding genes.

Genomic DNAs encoding the horseradish peroxidase (HRP) isozymes, prxC2 and prxC3, were cloned and sequenced. By comparing the sequences of the HRP isozyme-encoding genes, prxC1a and prxC1b and their cDNA [Fujiyama et al., Eur. J. Biochem. 173 (1988) 681-687], , it was concluded that prxC2 and prxC3 consisted of four exons and three introns as in the prxC1 gene family. The position of introns in coding regions were the same in all four prx genes. Genes prxC2 and prxC3 coded for 347 and 349 amino acid (aa) residues, respectively, including putative signal sequences at the N termini. In the flanking regions of both genes, putative promoters and polyadenylation signals were found. Nucleotide sequence homology in the coding region was 71% between prxC1a and prxC2, and 66% between prxC1a and prxC3. The aa sequence homologies in plant and microbial peroxidases were compared.

Amino Acid Sequence↗
PubMed1990

Purification of 1F5 antigen that prevents complement attack on homologous cell membranes.

A mAb, 1F5, has the ability to cause hemolysis by human serum of human E treated with neuraminidase via the alternative C pathway. By Western blotting, this mAb reacts with a glycoprotein having a molecular mass of 20 kDa (1F5Ag). 1F5Ag was isolated from human E by affinity chromatography with mAb-coupled Sepharose. Purified 1F5Ag was then adsorbed to guinea pig E rendering them resistant to human C attack by both the classical and the alternative pathways. Furthermore, experiments with isolated C components revealed that 1F5Ag interferes with both homologous human C8 and C9 in the terminal stage of the C reaction, whereas it has little effect on hemolysis by rabbit C8 and C9. Therefore, 1F5Ag can be called HRF20, which stands for homologous restriction factor of 20 kDa.

Amino Acid Sequence↗
PubMed1990

Cloning and sequence analysis of a cDNA for cellulase (FI-CMCase) from Aspergillus aculeatus.

We have cloned and characterized the cDNA coding for a major component of cellulase, endoglucanase (FI-CMCase), produced by Aspergillus aculeatus. The cDNA was isolated from a A. aculeatus cDNA library using synthetic oligonucleotide mixtures that correspond to the internal amino acid sequence of the mature FI-CMCase protein. Nucleotide sequence analysis of the cloned cDNA insert revealed a 711 bp open reading frame that encoded a protein of 237 amino acid residues. The primary structure of FI-CMCase deduced from the nucleotide sequence of cDNA agreed with that found by amino acid sequencing of peptide fragments obtained by digestion with several proteinases and cyanogen bromide cleavage. There may be a signal peptide sequence of 16 amino acid residues at the N-terminus. The molecular mass of the mature protein calculated from the cDNA is 24002 daltons, which compares favorably with molecular mass estimates of purified FI-CMCase obtained from SDS-PAGE (25000 Da). No distinct homology was found between the amino acid sequence of FI-CMCase and known cellulase sequences of other microorganisms. This study is the first example of cDNA cloning of an endoglucanase from the genus Aspergillus.

Amino Acid Sequence↗
PubMed1990

The effect of adjuvant therapy with or without tamoxifen on the endocrine function of patients with breast cancer.

The ovarian and pituitary functions of 64 operable breast cancer patients undergoing adjuvant therapy with cytotoxic chemotherapy and/or tamoxifen were investigated. The post menopausal patients, divided into 3 treatment groups, one with tamoxifen alone, one with tamoxifen and chemotherapy and the other with chemotherapy alone had serum estradiol 17-beta (E2) and progesterone levels lower than the evaluable limits. Although there was no significant difference in the level of estrone sulfate (E1-S) between these three groups, the level of lutainizing hormone (LH) and follicle stimulating hormone (FSH) in the patients treated with tamoxifen alone and tamoxifen and chemotherapy were significantly lower than those treated with chemotherapy alone. The decrease in gonadotropin levels induced by tamoxifen treatment was reversible as it appeared after the initiation of tamoxifen and recovered after its cessation. In the premenopausal patients, a group treated with tamoxifen and chemotherapy had significantly higher E1-S, E2 and progesterone levels and significantly lower gonadotropin levels than a group treated with chemotherapy alone or one treated with a cyclophosphamide regimen. These increases in the levels of estrogen and progesterone were also reversible, and induced by tamoxifen. Thus, adjuvant endocrinochemotherapy causes profound alteration in the hypothalamo-pituitary-ovarian axis and therefore, monitoring a variety of hormonal levels is thought to be necessary for assessing the consequences of adjuvant therapy in breast cancer patients, especially in premenopausal patients using tamoxifen.

Aged↗
PubMed1990

Brain abscess associated with congenital pulmonary arteriovenous fistula.

A case of brain abscess associated with congenital pulmonary arteriovenous fistula was presented and 52 reported cases were reviewed. The brain abscess was successfully treated with repeated aspiration and drainage, and the pulmonary arteriovenous fistula, located in the right lower lobe, was resected. The arteriovenous fistula occurs as a common pulmonary manifestation of hereditary hemorrhagic telangiectasia; however, no symptoms suggesting these two were noted in this case. Brain abscesses can be an initial clinical manifestation in asymptomatic pulmonary arteriovenous fistula. This possible association should be borne in mind in cases of brain abscesses of unexplained etiology.

Arteriovenous Fistula↗