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Biomedical subjects

K Miyai

Publications and source records attributed to K Miyai.

At least 91 records · Page 5Linked to original sources
PubMed1991

Epitope analysis of recombinant human thyrotropin.

Recombinant proteins and peptides are anticipated to become promising tools as reagents for immunoassays because of their constant availability and structural uniformity. However, careful assessment of their immunological properties is necessary prior to practical use. Epitope analysis of recombinant human thyrotropin (rec-hTSH) was recently performed in our laboratory. Details are to be published elsewhere (T. Kashiwai, K. Miyai et al.) but the results are briefly shown here.

Antibodies, Monoclonal↗
PubMed1991

[DNA diagnosis in endocrinological disease--pituitary disease].

Endocrine disorders have long been diagnosed by symptoms, before hormones were able to be measured by immunoassays. Recently, as molecular biological methods developed, DNA diagnosis has become available in many diseases including endocrine disorders. We present here DNA diagnosis in connection with anterior pituitary hormones. Our studies on thyrotropin (TSH) producing pituitary adenomas showed that TSH beta-subunit mRNAs of the adenomas were the same as those from normal pituitary tissues. Congenital isolated TSH deficiency is rare disease causing hypothyroidism including cretinism, severe mental and growth retardation. We have studied 3 families with consanguineous marriage and 2 families which were descendants of closed colonies. The molecular pathogenesis were elucidated in the cases of 3 Japanese families with consanguineous marriage. They had a same missense mutation in the 2nd exon of the TSH beta-subunit gene which made a restriction enzyme site, and could be analyzed either by genomic Southern blot analyses or by restriction enzyme digestion after amplification of genomic DNA by PCR. Congenital deficiency of growth hormone, prolactin, and TSH was first described in Snell dwarf mice. The gene encoding the nuclear factor Pit-1/GHF-1, which transactivates promoters of both growth hormone gene and prolactin gene, was shown to be the cause of Snell dwarf mice. A similar human case arose from a family with consanguineous marriage, and the relation with the pit-1/GHF-1 gene is now under study.

DNA↗
PubMed1991

[Converse changes in serum levels of immunoglobulins (IgG, A and M) and complement components (C3, 4) during pregnancy].

Sequential changes in serum levels of the immunoglobulins IgG, A and M and of the complements C3 and C4 during pregnancy and the postpartum period were studied in 8 healthy women. Serum IgG and A levels decreased gradually during pregnancy, but increased significantly during the first three months following delivery. Serum IgM level also decreased during pregnancy, reaching its minimum during the second trimester, but increased thereafter. In contrast, C3 and C4 levels increased significantly during pregnancy and reached their maximum levels during the last trimester. After delivery, levels of these two components decreased gradually for the next six months. The complement system may operate as a compensatory autoregulatory mechanism in the suppression of the humoral immune system during pregnancy.

Adult↗
PubMed1991

[Effect of plasma on analysis of lymphocyte subsets].

We examined the effect of plasma on the analysis of lymphocyte subsets with a flow cytometer using whole blood cells. Removal of plasma from whole blood by washing them before labelling the lymphocytes with fluorescein-conjugated antibodies reduced the proportion of CD5+CD19+ cells and increased the proportions of CD16+ CD57- and CD16+ CD57+ cells, as compared with those measured without washing, but did not change the proportions of CD5+ CD19-, CD5- CD19+, CD4+ CD8-, CD4- CD8+ and CD16- CD57+ cells. Removal of plasma from whole blood also reduced the fluorescence intensity of CD4 and CD5 antigens and increased that of CD8, CD16, CD19 and CD57 antigens on each lymphocyte subsets. Characteristics of the changed lymphocyte subsets were to have a surface antigen with weak immunofluorescence on the flow cytometric analysis such as CD5 and CD16, and to have an unclear borderline between the positive and negative cells. Therefore, even slight changes in the fluorescence intensity of these antigens could change the proportion of CD5+ CD19+, CD16+ CD57- and CD16+ CD57+ cells. However, these changes were not observed, when using the washed blood cells as samples after readdition of plasma to them. These data suggest that removal of plasma from blood before labelling the lymphocytes with fluorescein-conjugated antibodies is necessary to make the sample condition equal for flow cytometric analysis of lymphocyte subsets.

Adult↗
PubMed1991

[Mixed type cryoglobulinemia with discrepancy of platelet counts measured with an automated cell counter and by manual counting method].

We experienced an abnormal blood sample which showed larger numbers of white blood cells and platelets counted by the electric resistance system and of platelets in mechanical counting by the flow system, than those in manual counting. Many precipitates were observed in this blood sample at room temperature or 4 degrees C, but were not observed at 37 degrees C. The precipitates were clarified to be caused by the mixed type (IgA, IgG and IgM) cryoglobulin by using an immunofluorescence method and an ouchterlony method. These data indicate that precipitation of cryoglobulin at room temperature induce falsely high value of platelet count in mechanical counting systems.

Chemical Precipitation↗
PubMed1991

[Molecular biology and laboratory diagnosis of hypothalamic-pituitary-thyroid axis].

Recent developments in molecular biology have brought dramatic changes in laboratory medicine. Applications of molecular biology techniques have made it possible to make etiological diagnosis and produce recombinant proteins for reagents. Laboratory investigations of molecular biology in the hypothalamic-pituitary-thyroid axis include TRH gene, TRH effect, TSH gene, TSH receptor and its autoantibodies, thyroid peroxidase and thyroglobulin and their autoantibodies, thyroxine (T4) binding protein genes, deiodination of T4, thyroid hormone receptor, oncogenes of thyroid etc. The following developments are reviewed. 1) Human TSH (hTSH) beta gene and its abnormality: Two types of mutations of hTSH beta gene have been found in patients with hereditary isolated TSH deficiency. DNA diagnosis and genetic counseling are now being performed. 2) Structure and function of TSH receptor: The primary structure of hTSH receptor was identified from its gene. Relationships between its structure and function have been investigated using site specific mutagenesis and synthetic short peptides. 3) Thyroid hormone receptor gene and its abnormality: The thyroid hormone receptor gene has been successfully cloned. Several mutations of the gene have been demonstrated in patients with thyroid hormone resistance. 4) Application of recombinant hTSH (r-hTSH):r-hTSH has been produced in CHO cells. Immunological and biological properties of r-hTSH are similar to those of authentic pituitary hTSH. Clinical application of r-hTSH is now in progress.

Amino Acid Sequence↗
PubMed1991

[Phase II study of 5'-DFUR (Furtulon) capsule for bladder cancer].

A cooperative phase II study of 5'-DFUR at a daily dose of 800 to 1,200 mg was performed on 18 patients with bladder cancer. The therapeutic responses were evaluated by Koyama-Saito's criteria in 13 out of 18 patients, and 3 PR, 1 MR, 6 NC and 3 PD were obtained. Adverse reactions were observed in three out of 15 cases (20.0%). These side effects were reversible gastrointestinal symptoms such as nausea-vomiting, anorexia and diarrhea. The results suggest that 5'-DFUR is a useful drug for bladder cancer treatment.

Adenocarcinoma↗
PubMed1991

[Examination of the inhibitor to factor VIII in non-haemophilic patient].

We examined an inhibitor to factor VIII in non-haemophilic patient who had been developed widely spread ecchymosis and intramuscular bleeding. He had no previous personal or family history of abnormal bleeding tendency. His laboratory data was all normal except examination for blood coagulation. Coagulation studies showed prolonged activated partial thromboplastin time (48 sec) and decreased factor VIII activity (8%). The activity of the inhibitor to factor VIII was demonstrated to be 4.0 Bethesda unit. By the studies of dilution and time response curve, this inhibitor was found to inhibit up to 90% of factor VIII activity but not 100%. This inhibitor was shown to be IgG by protein-A affinity chromatography. In addition, bleeding time was prolonged in the patient. The value of von Willebrand factor antigen was 200%, but that of Ristocetin cofactor was 93%. Since the gel filtration analysis indicated that this inhibitor also suppressed Ristocetin cofactor activity, the relatively low value of Ristocetin cofactor might occur through the action of the inhibitor. These data suggest that patient's inhibitor react to factor VIII high molecular subunit.

Blood Coagulation Disorders↗
PubMed1991

[Two cases of TSH-secreting pituitary adenoma; endocrinological, diagnostic and therapeutic approach to the disease].

Two cases of TSH-secreting pituitary adenoma were reported. Endocrinological and immunohistochemical features of these cases were described and problems in diagnosis and treatment of the rare disease are discussed. [case 1] A 28 year-old woman suffered from hyperthyroidism with a relatively high value of serum TSH (T3; 350 ng/dl, T4; 10.0 micrograms/dl, TSH; 24.5 microU/ml). She was treated with antithyroid drug and then underwent subtotal thyroidectomy. Although the levels of serum T3 and T4 were lowered to within normal range, the level of serum TSH still remained high. One month later, she developed frontal headache, amenorrhea and bitemporal hemianopsia. A CT scan showed an enhanced mass in the sellar and suprasellar region. Preoperative endocrinological studies showed elevated values of TSH (47 microU/ml) and its alpha-subunit (9.0 ng/ml). The levels of both T3 (190 ng/dl) and T4 (10.0 micrograms/dl) were near the upper normal limit. Serum TSH was suppressed by administration of exogenous T3, but did not respond to exogenous TRH, l-Dopa nor bromocriptine. Under the diagnosis of TSH-secreting pituitary adenoma, the patient was operated on by craniotomy and received local radiation therapy (50 Gy). In 1990, 12 years after the treatment, she is well and endocrinologically normal. Immunohistochemical study revealed that most tumor cells were positive for TSH. [case 2] A 28 year-old woman visited our hospital for examination of hyperthyroidism. Serum level of TSH was detectable (4.5 microU/ml). A CT scan performed at that time disclosed no pituitary tumor. Thyroid function was normalized by antithyroid drug, but the level of TSH was still high and progressively increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1991

Automated determination of creatine kinase activity in serum with use of thermostable glucokinase.

We measured creatine kinase (CK, EC 2.7.3.2) activity in serum with a new reagent system utilizing thermostable glucokinase (EC 2.7.1.2). Automated determinations were performed with Toshiba's Model TBA-80S Biochemical Analyzer. Precision studies demonstrated within-run and between-run CVs of 0.4%-2.4% and 2.8%-3.1%, respectively. The response linearity was confirmed for CK activity up to 1000 U/L at 37 degrees C. CK activities correlated well (r = 0.997) with those obtained by the manual method recommended by the German Society for Clinical Chemistry (measuring at 37 degrees C) involving hexokinase (EC 2.7.1.1). However, CK activities measured by our method were consistently higher than those of the hexokinase method at reaction temperatures of 30, 37, and 40 degrees C. These data indicate that the new method with thermostable glucokinase is better than that with thermo-unstable hexokinase for determination of CK activity in serum.

Automation↗
PubMed1990

Hepatic passage of bile acids increases oxygen uptake by perfused rat liver.

It has been claimed that the hepatic passage of conjugated bile acids does not increase oxygen uptake by the isolated perfused rat liver. We studied a variety of bile acids in the single-pass perfused rat liver. All bile acids studied except taurocholate and tauro-beta-muricholate induced an increase in oxygen uptake of 2.1%-11.2% (baseline 2.54 +/- 0.57 mumoles/min per g liver). Raised values for oxygen uptake were not specifically associated with the critical micellar concentration of the bile acid, with bile acid uptake, or with bile acid secretion. It is postulated that bile acid toxicity may have an intracellular effect on hepatic oxygen uptake.

Animals↗
PubMed1990

Taurohyocholate, taurocholate, and tauroursodeoxycholate but not tauroursocholate and taurodehydrocholate counteract effects of taurolithocholate in rat liver.

The infusion of taurolithocholate (TLC) in vivo or in the isolated perfused liver of the rat causes cholestasis and cellular necrosis. In order to analyze the protective effect of bile salts differing in number and steric position of their hydroxy groups against TLC-induced cholestasis, isolated rat livers were perfused with taurocholate (TC), taurohyocholate (THC), tauroursocholate (TUC), taurodehydrocholate (TDHC), and tauroursodeoxycholate (TUDC) (16 and 32 mumol/l) with or without TLC (8 and 16 mumol/l). Bile flow, bile salt secretion, and the hydroxylation pattern of the bile salts secreted were analyzed. TLC caused complete cholestasis after 15 min of perfusion. All bile salts studied had a protective effect. THC, TC, and TUDC completely abolished the cholestasis induced by TLC while TUC did so only for the first 10 min. TDHC was protective only as long as it was biotransformed into hydroxyoxo bile salts. Coinfusion of bile salts did not influence uptake of TLC (greater than or equal to 93% of dose). Differences were found regarding the amount of TLC biotransformed (% of uptake): TC 50%; THC 32%; TUDC 36%; TUC 20%. Light microscopy revealed cellular necrosis, and dilated canaliculi were found in livers perfused with TLC only or in combination with TUC or TDHC, while the other bile salts prevented these changes. We conclude that bile salts with low micelle-forming capacity have little protective effect against TLC-induced cholestasis. These bile salts induce less biotransformation of TLC than TC, THC, and TUDC. The protective effect is not dependent on the hydrocholeretic effect of the added bile salt and is not due to an uptake inhibition.

Animals↗
PubMed1990

Tauroursodeoxycholate prevents taurolithocholate-induced cholestasis and toxicity in rat liver.

Ursodeoxycholate has been advocated for the treatment of cholestatic liver diseases. The coinfusion of tauroursodeoxycholate with taurolithocholate in the perfused rat liver completely prevented the decrease of bile flow and the increase of oxygen uptake found with taurolithocholate only. Bile flow and bile salt secretion were increased with the coinfusion of both bile acids as compared with the infusion of tauroursodeoxycholate only (+4.30 microliters/g liver per 30 min) with 16 and 32 mumol/l tauroursodeoxycholate (+1.55 microliters/g liver per 30 min with 80 and 160 mumol/l). Morphological examination revealed a 50% decrease of the number of necrotic cells in the periportal area. Tauroursodeoxycholate did not inhibit the uptake of taurolithocholate, but increased its transcellular passage and biotransformation. Thus, tauroursodeoxycholate prevents taurolithocholate-induced cholestasis and liver cell toxicity probably by an intracellular mechanism.

Animals↗
PubMed1990

Digoxin-like immunoreactivity in Chinese medicine.

Immunoreactive digoxin-like activity was observed in Chinese medicine, KYUSHIN tablet, taken popularly in Japan without prescription. The antibodies used in the assays of digoxin reacted with Chan-su, the major effective component of KYUSHIN, which contained cardiotonic steroids with similar chemical structure as digoxin. One tablet of KYUSHIN had digoxin-like immunoreactivity equivalent to 1.9, 1.5, and 72 micrograms of digoxin measured by three different commercial kits. These different equivalences may be attributed to differences in cross-reactivity of the antibody used in the immunoassays. Two healthy volunteers took two KYUSHIN tablets three times a day, a typical dose, and digoxin-like immunoreactivity reached almost 0.4 micrograms/L in 0.5 day. Therapeutic drug monitoring should be interpreted carefully in patients taking Chinese medicines, many of which contain the Chan-su component.

Cross Reactions↗
PubMed1990

Relationship between proliferation and cell cycle-dependent Ca2+ influx induced by a combination of thyrotropin and insulin-like growth factor-I in rat thyroid cells.

The mechanism of cell proliferation by a combination of thyroid-stimulating hormone (TSH) and insulin-like growth factor-I (IGF-I) was studied in rat thyroid (FRTL-5) cells. IGF-I stimulated an approximately 3.5-fold increase in the rate of Ca2+ influx sustained for at least 6 h in TSH-pretreated cells but not in quiescent cells. The significant cell proliferation was observed when TSH-primed cells were incubated with IGF-I for 24 h but not for 12 h. IGF-I stimulated the rate of Ca2+ influx in a dose-dependent manner that was similar to that for induction of DNA synthesis. Both Ca2+ influx and DNA synthesis observed in response to IGF-I in TSH-primed cells were inhibited by cobalt. In addition, the stimulations of Ca2+ influx and DNA synthesis by IGF-I were dependent on extracellular Ca2+ in TSH-pretreated cells. When TSH-primed cells were pretreated with pertussis toxin, both IGF-I-induced Ca2+ influx and DNA synthesis were abolished. However, pertussis toxin did not block the priming action of TSH or forskolin. When calcium entry was induced by Bay K8644, it stimulated cell growth in TSH-primed cells but not in quiescent cells. Moreover, cobalt and lanthanum inhibited DNA synthesis even when added several hours after the addition of Bay K8644 but not when added 24 h after the growth factor in TSH-primed cells. These findings suggest that at least two important mechanisms may work in response to IGF-I only in the TSH-primed G1 phase of the cell cycle: first, IGF-I can activate directly or indirectly the Ca2+ channel via a pertussis toxin-sensitive substrate in TSH-primed cells; and second, a long lasting calcium entry by IGF-I may be a cell cycle-dependent mitogenic signal.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1990

Interaction between theophylline and mexiletine.

Drugs influencing hepatic microsomal enzyme systems, such as mexiletine, may affect the elimination pattern of theophylline. The three patients reported here had a history of asthma and premature ventricular contractions, and were receiving theophylline therapy. A few days after starting the coadministration of mexiletine and theophylline, theophylline serum concentrations increased about twofold over concentrations during theophylline therapy. In one case, theophylline serum concentrations increased by 2.6 fold, and the patient developed nausea and anorexia. Mexiletine serum concentrations did not change. It seems that with mexiletine therapy, lower doses of theophylline may be required and careful monitoring of serum concentrations is necessary.

Aged↗