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Biomedical subjects

Y Hidaka

Publications and source records attributed to Y Hidaka.

At least 19 recordsLinked to original sources
PubMed2006

Attempted suicide, psychological health and exposure to harassment among Japanese homosexual, bisexual or other men questioning their sexual orientation recruited via the internet.

OBJECTIVE: To investigate the rates of attempted suicide and its association with psychological distress, experiences of bullying and verbal harassment, and demographic characteristics among Japanese homosexual, bisexual or other men questioning their sexual orientation. DESIGN: A cross-sectional design using Japanese participants recruited through the internet. RESULTS: Of the 1025 respondents, 154 (15%) of the men reported a history of attempted suicide, 716 (70%) showed high levels of anxiety and 133 (13%) showed high levels of depression. 851 (83%) experienced school bullying and 615 (60%) were verbally harassed because of being perceived by others as homosexual. Independent correlates of attempted suicide were psychological distress, history of being verbally harassed, history of sex with a woman, history of meeting a male through the internet, disclosing sexual orientation to six or more friends and not having a university degree. CONCLUSIONS: Mental health services and prevention programmes are needed to deal with the psychological consequences of social stigma for Japanese men who are homosexual, bisexual or questioning their sexual orientation.

Adolescent↗
PubMed2004

Hyper-production of an isomalto-dextranase of an Arthrobacter sp. by a proteases-deficient Bacillus subtilis: sequencing, properties, and crystallization of the recombinant enzyme.

Arthrobacter globiformis T6 is unique in that it produces an enzyme yielding only isomaltose from dextran. In the present study, the organism was re-identified and its classification as a new species of the genus Arthrobacter, A. dextranlyticum, was proposed. The high G+C gene (66.8 mol%) for the isomalto-dextranase was sequenced. The deduced amino acid sequence, with a calculated molecular mass of 65,993 Da (603 amino acids), was confirmed by nanoscale capillary liquid chromatography coupled to tandem mass spectrometry, which covered 71.1% of the amino acid residues of the entire sequence. The enzyme was grouped into glycoside hydrolase family 27, and the C-terminal domain has homology to carbohydrate-binding module family 6. Hyper-exoproduction of the recombinant enzyme was achieved at a level corresponding to approximately 4.6 g l(-1) of culture broth when proteases-deficient Bacillus subtilis cells were used as the host. The purified enzyme (65.5 kDa) had an optimal pH and temperature for activity of 3.5 and 60 degrees C, respectively. It was crystallized using the sitting-drop vapor-diffusion method at 293 K.

Amino Acid Sequence↗
PubMed2004

Enzymatic properties and nucleotide and amino acid sequences of a thermostable beta-agarase from a novel species of deep-sea Microbulbifer.

An agar-degrading bacterium, strain JAMB-A7, was isolated from the sediment in Sagami Bay, Japan, at a depth of 1,174 m and identified as a novel species of the genus Microbulbifer. The gene for a novel beta-agarase from the isolate was cloned and sequenced. It encodes a protein of 441 amino acids with a calculated molecular mass of 48,989 Da. The deduced amino acid sequence showed similarity to those of known beta-agarases in glycoside hydrolase family 16, with only 34-55% identity. A sequence similar to a carbohydrate-binding module was found in the C-terminal region of the enzyme. The recombinant agarase was hyper-produced extracellularly using Bacillus subtilis as the host, and the enzyme purified to homogeneity had a specific activity of 398 U (mg protein)(-1) at pH 7.0 and 50 degrees C. It was thermostable, with a half-life of 502 min at 50 degrees C. The optimal pH and temperature for activity were around 7 and 50 degrees C, respectively. The pattern of agarose hydrolysis showed that the enzyme was an endo-type beta-agarase, and the final main product was neoagarotetraose. The activity was not inhibited by NaCl, EDTA, and various surfactants at high concentrations. In particular, sodium dodecyl sulfate had no inhibitory effect up to 2%.

Alteromonadaceae↗
PubMed2002

Development of liver dysfunction after delivery is possibly due to postpartum autoimmune hepatitis. A report of three cases.

Autoimmune diseases, especially autoimmune thyroid disease, frequently develop after delivery due to the immune rebound mechanism. Most cases involve transient dysfunction of affected organs. We examined three patients who developed liver dysfunction after delivery. They were all diagnosed with definite or probable autoimmune hepatitis using the scoring system of the International Autoimmune Hepatitis Group. Moreover, all of them had anti-CYP2D6 antibodies detected by a sensitive radioligand assay. Our findings strongly suggest that liver dysfunction is induced by postpartum autoimmune hepatitis, and clinicians should be aware of this disease.

Adult↗
PubMed2001

NEDD8 recruits E2-ubiquitin to SCF E3 ligase.

NEDD8/Rub1 is a ubiquitin (Ub)-like post-translational modifier that is covalently linked to cullin (Cul)-family proteins in a manner analogous to ubiquitylation. NEDD8 is known to enhance the ubiquitylating activity of the SCF complex (composed of Skp1, Cul-1, ROC1 and F-box protein), but the mechanistic role is largely unknown. Using an in vitro reconstituted system, we report here that NEDD8 modification of Cul-1 enhances recruitment of Ub-conjugating enzyme Ubc4 (E2) to the SCF complex (E3). This recruitment requires thioester linkage of Ub to Ubc4. Our findings indicate that the NEDD8-modifying system accelerates the formation of the E2-E3 complex, which stimulates protein polyubiquitylation.

Anaphase-Promoting Complex-Cyclosome↗
PubMed2001

Possible induction of systemic lupus erythematosus by zonisamide.

An epileptic male to whom zonisamide and ethosuximide had been administered exhibited fever, pericarditis, pleuritis, arthralgia, and elevated titers of antinuclear antibody and anti-DNA-antibody at 5 years, 11 months of age. It was suggested that zonisamide induced the systemic lupus erythematosus symptoms because the antinuclear antibody titers began to rise after zonisamide was administered, and clinical recovery and a decrease in the anti-DNA-antibody levels promptly followed the discontinuation of the drug. The positive lymphocyte transformation test results against zonisamide further supports the etiologic relationship of the male's lupus and the drug. This first case of zonisamide-induced lupus should alert physicians to the possibility of this serious unwanted effect in patients receiving zonisamide.

Antibodies, Antinuclear↗
PubMed2001

Characteristics of experimental autoimmune hypophysitis in rats: major antigens are growth hormone, thyrotropin, and luteinizing hormone in this model.

We produced experimental autoimmune hypophysitis (EAH) in rats and investigated its characteristics. Female Lewis rats were immunized by two injections with homologous pituitary homogenate and complete Freund's adjuvant. Blood was collected serially from the rats, and serum antibodies to pituitary antigens were examined. The rats were sacrificed 2 or 4 weeks after the final immunization, and histological examinations of the endocrine organs were carried out. Histological examination revealed slight, focal infiltration of mononuclear cells in the pituitary gland only in the rats immunized with the pituitary homogenate. Infiltration of mononuclear cells was not observed in the thyroid gland, pancreas, adrenal gland, or ovary. In the serological examination, antibodies to both cytosolic antigens and cytoplasmic particle antigens from the pituitary gland were detected by enzyme-linked immunosorbent assay (ELISA), and these antibody levels increased with time. Western blotting using the serum antibodies identified an immunoreactive protein of approximately 21.5 kDa among these antigens, and we confirmed that this protein was rat growth hormone (GH). Furthermore, antibodies to GH, thyrotropin (TSH), and luteinizing hormone (LH) were detected by ELISA. Antibodies to follicule stimulating hormone, prolactin, or adrenocorticotropin were not detected. These data suggest that several antigens from the pituitary gland are involved in EAH in rats, and that GH, TSH, and LH are major antigens among the pituitary antigens in this model.

Animals↗
PubMed2001

Influence of breast-feeding on the production of cytokines.

PROBLEM: Recently, we reported increases in the production of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and IL-4 during the postpartum period. The present study was undertaken to investigate whether these increases might be explained by increased prolactin while breast-feeding. METHOD: Whole blood from 41 women who were breast-feeding, 13 women not breast-feeding, and 31 healthy non-pregnant women was stimulated with phorbol 12-myristate 13-acetate and ionomycin, and the levels of cytokines in the supernatant were measured by enzyme-linked immunosorbent assay. Their serum levels of prolactin were measured by enzyme immunoassay. RESULTS: Increases in IFN-gamma, IL-2, IL-4, and IL-10 production were observed in women who were breast-feeding but not in women who were not breast-feeding. Serum levels of prolactin correlated with the levels of IFN-gamma in culture supernatant. CONCLUSIONS: These results suggest that breast-feeding induces production of cytokines and that IFN-gamma production is enhanced by physiological concentrations of prolactin.

Breast Feeding↗
PubMed2001

Measles viruses on throat swabs from measles patients use signaling lymphocytic activation molecule (CDw150) but not CD46 as a cellular receptor.

Both CD46 and signaling lymphocytic activation molecule (SLAM) have been shown to act as cellular receptors for measles virus (MV). The viruses on throat swabs from nine patients with measles in Japan were titrated on Vero cells stably expressing human SLAM. Samples from all but two patients produced numerous plaques on SLAM-expressing Vero cells, whereas none produced any plaques on Vero cells endogenously expressing CD46. The Edmonston strain of MV, which can use either CD46 or SLAM as a receptor, produced comparable titers on these two types of cells. The results strongly suggest that the viruses in the bodies of measles patients use SLAM but probably not CD46 as a cellular receptor.

Animals↗
PubMed2001

Blocking type anti-tSH receptor antibodies detected by radioreceptor assay in Graves' disease.

We previously developed a radioreceptor assay which is presumably specific for detection of blocking-type anti-TSH receptor (TSHR) antibodies using unsolubilized porcine TSHR. Employing this assay, we measured blocking TSH-binding inhibitory immunoglobulin (TBII) in the sera from 30 untreated Graves' patients and compared the results with those of a bioassay measuring thyroid stimulation blocking antibodies (TSBAb). Blocking TBII was positive in 9 of 30 sera (30%) and the blocking TBII activity was correlated with the total TBII value, which was measured by the radioreceptor assay using solubilized porcine TSHR. On the other hand, TSBAb determined with the conventional bioassay was positive in only 2 sera (6.7%), and no correlation was observed with the TSAb activity. In some cases in which the TSAb activity was rather high, TSBAb could not be detected by bioassay, whereas blocking TBII was positive. There was no correlation of blocking TBII activity with goiter size, thyroid hormone level, or proptosis. However, there was a tendency for anti-thyroid therapy to require a shorter time for FT4 normalization in blocking TBII subjects, suggesting that blocking-type anti-TSHR antibody plays some role in the pathophysiology of Graves' disease. In conclusion, blocking type anti-TSHR antibodies are often found in the sera of Graves' patients when the blocking-specific radioreceptor assay is applied.

Adolescent↗
PubMed2000

Molecular cloning and characterization of a new human histamine receptor, HH4R.

A new histamine receptor, HH4R, was cloned from human leukocyte cDNA. The deduced amino acid sequence showed about 40% identity to that of the human histamine H3 receptor, HH3R. HH4R-expressing cells responded to histamine, inhibiting forskolin-induced cAMP accumulation. An H3 agonist, N-alpha-methylhistamine (NAMHA), bound specifically to HH4R, while another H3 agonist, R(-)-alpha-methylhistamine (RAMHA), and the H3 antagonist, thioperamide, competed with this binding. RAMHA, NAMHA, and imetit inhibited forskolin-induced cAMP accumulation in HH4R-expressing cells. However, the binding affinities and agonistic activities of H3 agonists to HH4R were weaker than those to HH3R. Low expression of HH4R was detected in a wide variety of peripheral tissues by RT-PCR; however, in contrast with HH3R, expression was not detected in the brain. These observations indicate that the clone is a distinct histamine receptor from HH3R, and thus is named HH4R.

Amino Acid Sequence↗
PubMed2000

Dual function of the propeptide of prouroguanylin in the folding of the mature peptide: disulfide-coupled folding and dimerization.

Guanylyl cyclase activating peptide II (GCAP-II), an endogenous ligand of guanylyl cyclase C, is produced via the processing of the precursor protein (prepro-GCAP-II). We have previously shown that the propeptide in pro-GCAP-II functions as an intramolecular chaperone in the proper folding of the mature peptide, GCAP-II (Hidaka, Y., Ohno, M., Hemmasi, B., Hill, O., Forssmann, W.-G., and Shimonishi, Y. (1998) Biochemistry 37, 8498-8507). Here, we report an essential region in pro-GCAP-II for the correct disulfide pairing of the mature peptide, GCAP-II. Five mutant proteins, in which amino acid residues were sequentially deleted from the N terminus, and three mutant proteins of pro-GCAP-II, in which N-terminal 6, 11, or 17 amino acid residues were deleted, were overproduced using Escherichia coli or human kidney 293T cells, respectively. Detailed analysis of in vivo or in vitro folding of these mutant proteins revealed that one or two amino acid residues at the N terminus of pro-GCAP-II are critical, not only for the chaperone function in the folding but also for the net stabilization of pro-GCAP-II. In addition, size exclusion chromatography revealed that pro-GCAP-II exists as a dimer in solution. These data indicate that the propeptide has two roles in proper folding: the disulfide-coupled folding of the mature region and the dimerization of pro-GCAP-II.

Amino Acid Sequence↗
PubMed2000

Enzyme-linked immunosorbent assay for anti-tropomyosin antibodies and its clinical application to various heart diseases.

Tropomyosin is one of the key proteins for muscle contraction. We developed an enzyme-linked immunosorbent assay for antibodies to porcine muscle tropomyosin and measured serum anti-tropomyosin antibodies in patients with heart diseases and in normal controls. The mean values of absorbance in the ELISA assay of patients with ischemic heart disease (n=36, P<0.001), dilated cardiomyopathy (n=28, P<0.005), valvular heart disease (n=27, P<0.05), and collagen disease (n=38, P<0.05) were significantly higher than those of normal controls (n=53), but the value in patients with hypertrophic cardiomyopathy (n=19) was not significantly different from that of normal controls. When the cut-off value was fixed at the mean+2 SD of absorbance in normal controls, positive reactions were found in 19.4%, 7.1%, 18.5% and 15.8% of patients with ischemic heart disease, dilated cardiomyopathy, valvular heart disease, and collagen disease, respectively. An inhibition study revealed that anti-tropomyosin antibodies were different from anti-myosin antibodies, but there was a partial cross-reactivity between the two. Thus, there was a weak correlation of the titers of the two types of antibody within the group of heart diseases. These data indicate that measurement of anti-tropomyosin antibodies by ELISA is helpful for detecting autoimmune abnormalities in various heart diseases.

Adult↗
PubMed2000

A BASH/SLP-76-related adaptor protein MIST/Clnk involved in IgE receptor-mediated mast cell degranulation.

Cross-linking of the high-affinity IgE receptor (FcepsilonRI) on mast cells by IgE-antigen complex triggers signal transduction cascades leading to the release of inflammatory mediators and production of cytokines, which are critical for the development of allergic reactions. We have identified a novel member of the BASH/SLP-76 immunoreceptor-coupled adaptor family expressed in mast cells, termed MIST (for mast cell immunoreceptor signal transducer), which has later been found to be identical to a recently reported cytokine-dependent hemopoietic cell linker, Clnk. Upon FcepsilonRI cross-linking, MIST/Clnk is tyrosine phosphorylated and associates with signaling proteins, phospholipase Cgamma, Vav, Grb2 and linker for activation of T cells (LAT). Overexpression of a mutant form of MIST/Clnk inhibited FcepsilonRI-mediated degranulation, increase in intracellular Ca(2+), NF-AT activation and phosphorylation of LAT. As a crucial signaling component for FcepsilonRI-induced mast cell degranulation, MIST/Clnk might serve as a target for anti-allergic therapy.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Changes in cytokine production during and after normal pregnancy.

PROBLEM: The systemic T helper 1/T helper 2 (Th1/Th2) cytokine balance during normal human pregnancy is controversial, and observations about the balance in the postpartum period have only been reported for up to 3 months. METHOD: Whole-blood, from 83 healthy pregnant women, 80 healthy postpartum women, and 31 healthy non-pregnant women was stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin, and the levels of cytokines in the supernatant were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: The production of all measured cytokines decreased during pregnancy, especially in the second trimester. After delivery, interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) increased from 2 to 11 months postpartum, and IL-4 increased from 6 to 11 months postpartum. CONCLUSIONS: These data indicate that 1) decreases in production of both Th1-and Th2-type cytokines during pregnancy may be related to the pregnancy-induced amelioration of autoimmune diseases: 2) increases in production of both Th1- and Th2-type cytokines in the postpartum period may be related to the postpartum aggravation of autoimmune diseases.

Adult↗
PubMed2000

Relationship between breast milk feeding and atopic dermatitis in children.

OBJECTIVE: To determine whether or not the breast milk feeding has a role in the prevalence of atopic dermatitis among children. METHODS: The target population of the study was all children participating in health check-up program for 3-year-old children in 60 municipalities locating 10 selected prefectures during designated 2 months between October and December 1997. Using a questionnaire, information on nutrition in infants (breast milk only, bottled milk only, or mixed), parity, mothers' age at birth, and a history of atopic dermatitis was obtained. Besides, data on potential confounding factors were obtained. RESULTS: Questionnaires from 3856 children (81.6% of those who were to participate in the programs, and 96.4% of children who participated them) were analyzed. After the adjustment for all potential confounding factors using unconditional logistic models, the risk of atopic dermatitis was slightly higher among children with breast milk (odds ratio [OR] = 1.16 with 95% confidence interval [CI] 0.96-1.40). Mothers' age at birth (OR for those who were more than 30 years or older in comparison with those who were younger than 30 years = 1.15; 95% CI, 0.96-1.37) and those with second or later parity orders (OR = 1.14, 95% CI; 0.95-1.35) showed odds ratios that were higher than unity without statistical significance. CONCLUSION: Breast milk elevates the risk of atopic dermatitis slightly without statistical significance; the risk may be, however, higher in children in second or later parity orders.

Adult↗