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Biomedical subjects

K Yuri

Publications and source records attributed to K Yuri.

At least 37 records · Page 2Linked to original sources
PubMed1999

A new human synovial sarcoma cell line, HS-SY-3, with a truncated form of hybrid SYT/SSX1 gene.

Recent cytogenetical and molecular studies have indicated that synovial sarcoma harbors a t(X;18)(p11.2;q11.2) translocation, resulting in the formation of a hybrid SYT/SSX (SSX1 or SSX2) gene. We newly established a human cell line, HS-SY-3, from a synovial sarcoma. HS-SY-3 cells were shown to harbor the pathognomonic t(X;18)(p11.2;q11.2) translocation by chromosome analysis but not to exhibit the classical hybrid SYT/SSX transcripts induced by this translocation, using RT-PCR. To determine the reason for this discrepancy, we analyzed cDNA from HS-SY-3 cells, as well as the original sarcoma tissue by the rapid amplification of cDNA 3' end assay, and found that the chimaeric cDNA was 240 bp shorter than the previously established SYT/SSX1 cDNA due to truncation of the 3' side of SSX1. The HS-SY-3 cells should be useful for future functional studies of the SYT/SSX chimeric gene.

Aged↗
PubMed1999

cDNA sequence, mRNA expression, and chromosomal localization of human carbonic anhydrase-related protein, CA-RP XI.

A full-length cDNA clone of a human carbonic anhydrase-related protein, CA-RP XI encoded by CA11, was obtained and sequenced. The cDNA sequence was 1475 bp long and predicted to encode a 328-amino acid polypeptide with a molecular mass of 36200 Da. The deduced amino acid sequence of CA-RP XI showed an overall similarity of 42-53% to the active site residues of other active CA isozymes; however, it lacked three zinc-binding histidine residues, raising questions regarding its CA catalytic activity. Northern blot analysis demonstrated strong expression of an approx. 1.5 kb transcript in the human brain, particularly in the cerebellum, cerebral cortex, and putamen. A single copy of the CA11 gene was localized to the human chromosome 19q13.2-3. These results suggest that CA-RP XI plays a general role in the human central nervous system.

Amino Acid Sequence↗
PubMed1999

Long-term lack of endogenous glucocorticoids down-regulates glucocorticoid receptor levels in the rat forebrain.

To understand the effect of a chronic lack of endogenous glucocorticoids on glucocorticoid receptor levels, the changes of glucocorticoid receptor content in the rat forebrain five months after adrenalectomy were investigated. In the long-term adrenalectomized rats that showed a hormone deficiency and loss of glucocorticoid receptor immunoreactivity in the forebrain, an intraperitoneal injection of corticosterone was used to elevate the serum hormone levels and recover glucocorticoid receptor immunoreactivity in the forebrain. One hour later, when the blood corticosterone returned to the normal level, the recovery of glucocorticoid receptor immunoreactivity in the forebrain was examined by immunohistochemistry. Since the complete restoration of glucocorticoid receptor immunoreactivity was shown to depend on the presence of normal levels of both serum hormone and intracellular glucocorticoid receptors, the weak reappearance of glucocorticoid receptor immunoreactivity in any forebrain area of the long-term adrenalectomized rats that had normal serum corticosterone might reflect the low intracellular glucocorticoid receptor levels there. Our results revealed a weak reappearance of glucocorticoid receptor immunoreactivity in some forebrain areas of the long-term adrenalectomized rats after corticosterone treatment; the hippocampal granule cell layer and cerebral cortex in particular showed very weak recovery of glucocorticoid receptor immunoreactivity. Conversely, neurons in the CA1/CA2 subfields of the hippocampal pyramidal cell layer, immediately adjacent to the granule cell layer on the same brain section, exhibited a strong reappearance of glucocorticoid receptor immunoreactivity, to near normal levels. These results suggest that, five months after adrenalectomy, the intracellular glucocorticoid receptor content decreased in the rat granule cell layer and cerebral cortex. Therefore, the long-term lack of endogenous glucocorticoids after adrenalectomy might down-regulate but not up-regulate the intracellular glucocorticoid receptor level, and the presence of glucocorticoids is important for the continued synthesis of glucocorticoid receptors.

Adrenalectomy↗
PubMed1999

Varicella-zoster virus-specific cellular immunity in subjects given acyclovir after household chickenpox exposure.

The time course of primary cell-mediated immune responses to varicella-zoster virus (VZV) among persons receiving acyclovir prophylaxis after exposure to chickenpox has not been well defined. Fifteen children who had household exposure to varicella received prophylactic acyclovir (40 mg/kg/day for 7-14 days after exposure) and were studied for development of both antibody and cell-mediated immunity (CMI) to VZV. Twelve developed antibodies and/or CMI; 10 had no symptoms and 2 manifested mild varicella. Two were already immune to varicella and had booster immune responses. One was not infected and subsequently developed full-blown varicella. Although acyclovir given after exposure to VZV is highly effective and does not appear to attenuate the immune response, it remains necessary to confirm whether, in the absence of clinical varicella, persons acquire specific immunity.

Acyclovir↗
PubMed1999

Treating neonatal rats with 6-hydroxydopamine induced an increase in voluntary alcohol consumption.

Brain dopamine (DA) and serotonin (5-HT) neurotransmission have been implicated in the mediation of alcohol-seeking behavior. We examined the effects of treatment of neonatal rats (3 days after birth) with the neurotoxin 6-hydroxydopamine (6-OHDA; 100 microg/10 microl, intracerebroventricularly) on the relationship between the levels of neurotransmitters and alcohol drinking behavior at the age of 14 weeks. 6-OHDA treatment reduced the levels of DA and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens (ACC), frontal cortex, striatum (STR), tegmentum/substantia nigra, and dorsal raphe nucleus. 5-HT levels in the ACC and STR were increased in the 6-OHDA-treated rats. 6-OHDA-treated rats showed increased alcohol consumption. There was a significant change in the ratio of [5-hydroxyindoleacetic acid]/[5-HT] in the ACC and STR of the treated rats, but no difference in the ratio of [DOPAC]/[DA] between the sham-operated controls and treated rats. 6-OHDA-treated rats had dopaminergic dysfunction in the five brain regions related to the reward system, in part, and a decrease in 5-HT turnover, including the accumulation of 5-HT in the ACC and STR. Furthermore, basal extracellular releases of DA and 5-HT of the ACC were significantly lower in the 6-OHDA-treated rats, compared with the controls. It was suggested that alcohol seeking behavior is associated with the alterations of dopaminergic neurons and the release of 5-HT in the mesocorticolimbic system.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1999

Serotypes and virulence factors of Escherichia coli strains isolated from dogs and cats.

E. coli strains isolated from urine of dogs and cats with urinary tract infections (UTI) and from feces of healthy one's were serotyped, and the serotypes were correlated with uropathogenic virulence factors. The most prevalent O-serotypes, O4 and O6, were isolated from dogs and cats with UTI. In contrast, O11 and O102 strains were the most frequently found from feces of healthy dogs and cats. Most of type O4 and O6 strains possessed such virulence factors as pil, pap, sfa, hly, and cnf1, while most type O11 and O102 strains pil only or pil and aer. All strains of type O75 possessed afaI and aer. K1 antigen was negative in all strains obtained from UTI.

Animals↗
PubMed1998

Immunocytochemical analysis of sex differences in calcitonin gene-related peptide in the rat dorsal root ganglion, with special reference to estrogen and its receptor.

Previous studies have shown that the calcitonin gene-related peptide (CGRP) immunoreactivity in the central nervous system (CNS) of adult rats is sexually dimorphic and regulated by sex steroid. In the present study, we used immunocytochemistry to investigate the sex difference in CGRP-immunoreactive (IR) neurons in rat dorsal root ganglia (DRG). The numbers of CGRP-IR neurons at the cervical, lumbar and sacral levels in the female rats were significantly lower than those of the male rats. We also found that the number of CGRP-IR neurons at the lumbar level was increased in ovariectomized (OVX) rats, but was decreased in estradiol (E2)-treated rats (OVX+E2). A large number of estrogen receptor (ER)-IR neurons at the lumbar level were found in the female rats, and its number was greater than that in the male rats. We also investigated the change in the number of ER-IR neurons of OVX rats after estrogen treatment. The number of ER-IR neurons in the OVX+E2 rats was consistent with that of the intact female rats, but was significantly increased in the OVX rats. As shown by a double-labeling immunocytochemical method, over 80% of the CGRP-IR neurons at the lumbar level showed ER immunoreactivity in the female, OVX and OVX+E2 rats, compared to only about 46% in the male rats. These results indicate that there is a gender difference in CGRP expression in the rat DRG, and that this CGRP expression might be downregulated by estrogen (at least in part) through its receptor.

Animals↗
PubMed1998

In vivo time course of morphological changes and DNA degradation during the degeneration of castration-induced apoptotic prostate cells.

The in vivo time course of the morphological changes and DNA degradation in castration-induced apoptotic prostate cells was studied from the earliest to the latest stage of the degeneration process. To study this problem, we first induced apoptotic prostate cells in rats by castration for 3 days and then promptly and continuously blocked the death of healthy prostatic cells in the castrated rats by in vivo testosterone replacement. Because testosterone replacement could not stop the irreversible lysis of already damaged prostate cells, apoptotic cells at different stages of the degeneration process were eliminated sequentially from the prostate after the healthy prostate cells had been protected. Prostate cells at the earliest stage of apoptosis at the time when the castrated rats received testosterone replacement disappeared last. By tracing the morphological and DNA degradation of apoptotic cells after hormone treatment, we estimated the time course of prostate cell death from the early to the final stage. In the morphological evolution of apoptotic prostate cells, the clumping of nuclear chromatin, the degeneration of cytoplasm and the involution of the cell surface occurred and progressed simultaneously, resulting in the rapid formation of apoptotic bodies that were gradually digested by other cells. The DNA ladders of apoptotic cells were progressively cleaved into a mononucleosomal subunit that was further degraded at an additional site, generating a heterogeneous population of small nucleotides. The final digestion of DNA fragments occurred within the apoptotic bodies. The whole course of prostate cell death after castration took about 44 h.

Animals↗
PubMed1998

Steroid hormones and their receptors in the brain.

Steroid hormones regulate several important functions of the brain by altering the expression of particular genes through their receptors. First in this paper the localization of glucocorticoid receptor immunoreactivity and mRNA in the brain was examined. Second biphasic effects of glucocorticoid on the hippocampus was described and particular emphasis was given on the apoptosis. Third the significance of estrogen receptor in the sexually dimorphic areas was discussed. These results suggest that steroids modulate the gene expression along with the alteration of cell structures in a different manner in a tissue-specific pattern.

Animals↗
PubMed1998

The effects of oestrogen and progesterone on serotonin and its metabolite in the lateral septum, medial preoptic area and ventromedial hypothalamic nucleus of female rats.

The effects of sex steroid hormones on serotonin and its metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA) in the lateral septal nucleus (LS), the medial preoptic area (MPA) and the ventromedial nucleus of the hypothalamus (VMH) of female rats were investigated, using immunohistochemistry and high-performance liquid chromatography (HPLC). Female rats were divided into three groups: ovariectomized rats (OVX group); OVX-rats treated with estradiol benzoate alone (E2 group); and OVX-rats treated with E2 plus progesterone (E2 + P group). We analysed the density of serotonin-immunoreactive fibres with a computer-assisted image analysis system, and measured the tissue concentrations of serotonin and 5-HIAA. Many serotonin-immunoreactive fibres were observed in the LS, MPA and VMH in all three groups. The density of serotonin-immunoreactive fibres in the MPA and VMH was significantly lower in the E2 and E2+P groups compared to the OVX group, whereas the LS showed no detectable differences among the three groups. In the HPLC study, the concentrations of serotonin in the MPA and VMH of the E2 and E2+P groups were significantly lower than that in the OVX group. There was no significant difference in the concentration of serotonin in the LS. The concentration of 5-HIAA and the ratio of 5-HIAA/serotonin in the LS, MPA and VMH showed no significant differences among the OVX, E2 and E2+P groups. The present results suggest that E2 priming for sexual behaviour can affect the serotonergic system by decreasing serotonin content, but not the turnover rate, in the MPA and VMH of female rats.

Animals↗
PubMed1998

Isometric contractile properties of single myofibrils of rabbit skeletal muscle.

The isometric contractile properties of single myofibrils of rabbit skeletal muscle were studied at various sarcomere lengths. Single myofibrils were suspended between the tips of one rigid and one flexible glass microneedle, and their force production was determined by detecting the bending of the flexible microneedle photo-electronically. The active force vs. sarcomere length relation had an ascending limb (0.7-2.25 micron), a plateau (2.25-2.5 micron), and a descending limb (2.5-3.8 micron), which was similar to that of frog skeletal muscle. The passive force became increasingly apparent beyond a sarcomere length of 2.4 micron. These results can reasonably be explained based on the sliding filament mechanism by assuming the sarcomere geometry of rabbit muscle. The plateau, with a produced force of about 256 kN/m2, and the linear decline of force in the descending limb of the single myofibrils were essentially the same as those for frog muscle fibers. However, the slope of the force decline in the ascending limb was far steeper than that for frog muscle. This suggests that internal elements of sarcomeres are different between rabbit and frog muscles.

Animals↗
PubMed1998

Distribution of uropathogenic virulence factors among Escherichia coli strains isolated from dogs and cats.

A variety of virulence factors (VFs) such as type 1 fimbriae, pilus associated with pyelonephritis, S fimbriae, afimbrial adhesin, alpha-hemolysin, aerobactin and cytotoxic necrotizing factor 1 are associated with uropathogenic Escherichia coli. In this study, 80 uropathogenic E. coli strains in 50 dogs and 30 cats suffering from UTI. In addition, 60 E. coli strains were isolated from fecal samples from 30 each of healthy dogs and cats. The distribution of VFs of uropathogenic E. coli strains isolated from dogs and cats suffering from urinary tract infections (UTI) were examined by the colony hybridization test with seven DNA probes specific for VFs, and the results were compared with those obtained in the studies on strains from humans with UTI. In uropathogenic E. coli strains isolated from dogs and cats suffering from UTI, VFs were detected as frequently as in the strains isolated from humans with UTI. Although less frequently, genes encoding these VFs especially pap, sfa, hly, and cnf 1 genes were also associated with E. coli strains isolated from feces of healthy cats, in contrast to the distribution pattern of uropathogenic E. coli observed in humans. Furthermore, all VFs except pil were significantly more frequently detected in strains isolated from urine of animals with cystitis than in those isolated from feces of healthy humans. These results indicate that VFs of E. coli contribute to the pathogenesis of UTI in dogs and cats.

Adhesins, Bacterial↗
PubMed1997

Adrenalectomy-induced granule cell death is predicated on the disappearance of glucocorticoid receptor immunoreactivity in the rat hippocampal granule cell layer.

In this study, we observed the changes of glucocorticoid receptor (GR)-immunoreactivity (ir) and cell death in the rat hippocampal granule cell layer at various periods after adrenalectomy (ADX). Our results revealed that all of the rats shortly after ADX showed a rapid loss of GR-ir and subsequent appearance of degenerating cells in the granule cell layer. One month after ADX, however, about 80% of the rats displayed a restoration of GR-ir and the absence of degenerating cells in the granule cell layer, and this phenomenon was successively noted for 6 months. Hippocampal structural destruction 3 and 6 months after ADX was found in about 20% of the rats with loss of GR-ir in the granule cell layer; the ADX rats with even weak GR-ir in this area had a normal hippocampus. The treatment of rats with synthetic GR agonist, dexamethasone, immediately after ADX prevented the loss of GR-ir and significantly reduced the number of degenerating cells in the granule cell layer. Our results clarified that granule cell death after ADX was necessarily accompanied by the disappearance of GR-ir in the granule cell layer, suggesting that ADX-induced granule cell death is predicated on the loss of GR-ir and that the presence of GR-ir in this area may be important for granule cell survival.

Adrenalectomy↗
PubMed1997

Differential expression of estrogen receptor mRNA and protein in the female rat preoptic area.

The expression of estrogen receptor (ER) mRNA and ER protein in the medial preoptic area of ovariectomized rat was investigated at both cellular and regional levels using non-isotopic in situ hybridization and immunohistochemistry. ER mRNA was localized in the cytoplasm, while both liganded and unliganded forms of the ER protein were confined to the nucleus. Furthermore, ER mRNA containing cells were evenly distributed throughout the medial preoptic area, showing a homogeneous staining pattern compared to that of ER protein. ER immunoreactive cells were highly distributed in the medial, moderately in the lateral aspect of the medial preoptic area, showing a heterogeneous staining pattern with strongly and weakly labeled cells. These results suggest that ER protein levels are controlled by cellular posttranscriptional mechanisms.

Animals↗
PubMed1997

The in vivo time course for elimination of adrenalectomy-induced apoptotic profiles from the granule cell layer of the rat hippocampus.

Although apoptotic cellular degeneration has been reported to be extremely rapid with the use of in vitro models, the time needed to clear apoptotic neurons in the in vivo brain is unknown. In this study we used a simple morphological approach to solve this problem. Four days after adrenalectomy (ADX), all of the operated rats morphologically displayed hippocampal granule cell apoptosis that was prevented completely by corticosterone replacement immediately after ADX. Therefore, we intravenously injected the rats with corticosterone 4 d after ADX and subsequently maintained them on corticosterone replacement in saline drinking water. This corticosterone replacement could protect healthy granule cells promptly and continuously against hormone-deficient apoptosis, because the normal glucocorticoid receptor immunoreactivity within the granule cell nuclei, which disappeared after ADX, was identified 1 hr after corticosterone replacement was started, and this effect persisted for several days. However, this corticosterone treatment could not prevent the irreversible apoptosis of the already degenerated granule cells at various stages of the same progressive apoptotic process. Then we successively traced the disappearance of apoptotic granule cells throughout the hippocampus at different time points by Nissl and silver staining. Given that the apoptotic cells at the earliest stage of the degenerating process when the ADX rats received corticosterone injection were the last to disappear, the period from corticosterone injection until the disappearance of the last degenerating debris of apoptotic cells was taken to represent the time course for elimination of apoptotic neurons in vivo. We discovered that the elimination of apoptotic granule cells took 72 hr.

Adrenalectomy↗
PubMed1997

The mechanisms of transient hypothyroxinemia in infants born to mothers with Graves' disease.

Transient hypothyroxinemia in infants born to mothers with Graves' disease is a unique disorder first reported by us in 1988. Most mothers of these infants have had no treatment, are diagnosed as having thyrotoxicosis during the last trimester, or were not well controlled during pregnancy. These infants are believed to have transient central hypothyroidism, the mechanisms of which have not been elucidated. We measured TSH-receptor antibody activities in maternal serum and blood thyroxine (T4) (free thyroxine, FT4) and TSH levels in blood dried on filter paper at 1, 3, and 5 d of age in 114 infants born to mothers with Graves' disease. The 114 infants were retrospectively divided into three groups according to the clinical course and thyroid function data: group G, neonatal thyrotoxicosis; group T, transient hypothyroxinemia; and group E, euthyroid. In group T, the dried blood T4 (FT4) level from cord blood and/or 1 d of age blood was 6.0 +/- 2.3 microg/dL (0.92 +/- 0.52 ng/dL), a value significantly higher than that at 5 d of age (3.6 +/- 1.0 microg/dL; 0.38 +/- 0.18 ng/dL) (p = 0.025 in T4, p = 0.042 in FT4). In contrast, these levels were significantly lower at birth relative to 5 d in group G (p = 0.0001 in T4) and not significantly changed in group E. The TSH level of cord blood and/or 1-d-old blood in group T was significantly lower than that of group E (p = 0.0006). Moreover, the TSH levels in response to thyrotropin-releasing hormone were blunted in most infants in group T. Bone maturation was not delayed in group T, compared with euthyroid infants. The higher blood T4 (FT4) levels at birth, relative to 5 d in group T, suggested that the fetal T4 level was higher than that of the newborn period. The fetal T4 level might have been elevated owing to transfer of T4 from mother to fetus during the last trimester when the mother's thyroid function was elevated and consequently the fetal pituitary-thyroid axis was suppressed. Although the serum T4 (FT4) levels were decreased after birth, TSH levels were not elevated, probably because the pituitary-thyroid axis was suppressed. This may be the reason for the transient hypothyroxinemia with a normal TSH level in infants born to mothers with poorly controlled Graves' disease. Weak maternal thyroid-stimulating antibody activities and differences in sensitivity of the thyroid gland to TSH-receptor antibodies may contribute to this unique disorder.

Bone Development↗
PubMed1996

The perinatal ontogeny of estrogen receptor-immunoreactivity in the developing male and female rat hypothalamus.

Developmental expression of the estrogen receptor (ER) in rat hypothalamus was examined using immunohistochemistry. In the medial preoptic nucleus and ventromedial nucleus ER-immunoreactivity was detected as early as E17, whereas ER protein expression in the periventricular preoptic nucleus and arcuate nucleus was delayed until E19. These results show that following a region specific onset of the ER protein expression sex differences in ER levels are already detectable during the perinatal period.

Animals↗