Biomedical subjects

Yuko Kobayashi

Publications and source records attributed to Yuko Kobayashi.

16 recordsLinked to original sources

PubMed2006

Identification and characterization of GSRP-56, a novel Golgi-localized spectrin repeat-containing protein.

Spectrin repeat (SR)-containing proteins are important for regulation of integrity of biomembranes, not only the plasma membrane but also those of intracellular organelles, such as the Golgi, nucleus, endo/lysosomes, and synaptic vesicles. We identified a novel SR-containing protein, named GSRP-56 (Golgi-localized SR-containing protein-56), by a yeast two-hybrid method, using a member of the transient receptor potential channel family, TRPV2, as bait. GSRP-56 is an isoform derived from a giant SR-containing protein, Syne-1 (synaptic nuclear envelope protein-1, also referred to as Nesprin-1 or Enaptin), predicted to be produced by alternative splicing. Immunological analysis demonstrated that this isoform is a 56-kDa protein, which is localized predominantly in the Golgi apparatus in cardiomyocytes and C2C12 myoblasts/myotubes, and we found that two SR domains were required both for Golgi targeting and for interaction with TRPV2. Interestingly, overexpression of GSRP-56 resulted in a morphological change in the Golgi structure, characterized by its enlargement of cis-Golgi marker antibody-staining area, which would result partly from fragmentation of Golgi membranes. Our findings indicate that GSRP-56 is a novel, particularly small Golgi-localized member of the spectrin family, which possibly play a role in maintenance of the Golgi structure.

Animals↗

PubMed2006

Pathological study of Fitz-Hugh-Curtis syndrome evaluated from fallopian tube damage.

AIM: To analyze the causative pathogen, surgical indication and fallopian tube damages in Fitz-Hugh-Curtis syndrome (FHCS) cases diagnosed by laparoscopy. METHODS: Laparoscopic findings in 3568 cases at our hospital were reviewed retrospectively. Of these, 108 cases were diagnosed to have FHCS and examined for causative pathogens. Chlamydial infection was determined by both Chlamydia trachomatis (CT) antigens in the cervix and serum anti-CT antibodies. One hundred and four cases with chronic FHCS were divided into hydrosalpinx (H) and normal (N) groups based on the fallopian tube conditions, and were compared for patient profiles, tubal functions and perihepatic adhesion. RESULTS: Among surgical indications, tubal infertility and ectopic pregnancy were more often associated with FHCS than any other diseases. The primary causative pathogen of FHCS was CT. In 104 cases with chronic FHCS, there was no difference in CT antigen positivity between the H and N groups. The serum anti-CT IgG titer also did not differ between the two groups, although anti-CT IgA was slightly higher in the H group. The peritubal adhesion score was significantly higher in the H group, but it was not correlated with the degree of perihepatic adhesion. CONCLUSION: While some FHCS patients had severe fallopian tube dysfunctions, such as hydrosalpinx and tubal occlusion, 30% of FHCS cases did not show any abnormalities in the fallopian tube. Our study indicated that the severity of tubal dysfunctions associated with FHCS is determined by the host's reactivity to CT.

Adult↗

PubMed2006

High expression of eosinophil chemoattractant ecalectin/galectin-9 in drug-induced liver injury.

BACKGROUND: Ecalectin/galectin-9 (ECL/GL9) is an eosinophil chemoattractant isolated from T lymphocytes. Drug-induced liver injury (DILI), often caused by an allergic mechanism, is occasionally accompanied by eosinophilic infiltration. In this study, we intended to determine whether DILI can induce augmentation of ECL/GL9 expression. Further, we investigated whether this augmentation is associated with tissue eosinophilia. METHODS: We examined the expression of ECL/GL9 in biopsy specimens of DILI using the immunohistochemical technique. A rabbit anti-ECL/GL9 antibody was produced by immunizing rabbits with synthetic peptide corresponding to a molecular epitope of ECL/GL9. Thereafter, immunohistochemical staining with the use of this antibody was performed on 16 DILI needle biopsy specimens, and on biopsy specimens of chronic viral hepatitis, liver cirrhosis, and normal liver tissues as controls. RESULTS: In all cases of DILI specimens, but not in control liver specimens, a clear positive staining for ECL/GL9 was observed. Such positive staining was noted on Kupffer cells, fibroblasts, and histiocytes, but not on lymphocytes or hepatocytes. However, the intensity of immunolabeling did not correlate with the extent of eosinophile leukocyte infiltration. CONCLUSION: High expression of ECL/GL9 is suggested to be a specific finding of DILI. However, tissue eosinophilia in DILI cannot be explained by the augmentation of ECL/GL9 expression.

Adult↗

PubMed2005

Protective effects of Ca2+ handling drugs against abnormal Ca2+ homeostasis and cell damage in myopathic skeletal muscle cells.

Deficiency of delta-sarcoglycan (delta-SG), a component of the dystrophin-glycoprotein complex (DGC), causes skeletal muscular dystrophy and cardiomyopathy in BIO14.6 hamsters. Here, we studied the involvement of abnormal Ca2+ homeostasis in muscle degeneration and the protective effect of drugs against Ca2+ handling proteins in vivo as well as in vitro. First, we characterized the properties of cultured myotubes from muscles of normal and BIO14.6 hamsters (30-60 days old). While there were no apparent differences in the levels of expression of various Ca2+ handling proteins (L-type Ca2+ channel, ryanodine receptor, SR-Ca2+ ATPase, and Na+/Ca2+ exchanger), muscle-specific proteins (contractile actin and acetylcholine receptor), or DGC member proteins except SGs, BIO14.6 myotubes showed a high degree of susceptibility to mechanical stressors, such as cyclic stretching and hypo-osmotic stress as compared to normal myotubes, as evidenced by marked increases in creatine phosphokinase (CK) release and bleb formation. BIO14.6 myotubes showed abnormal Ca2+ homeostasis characterized by elevated cytosolic Ca2+ concentration, frequent Ca2+ oscillation, and increased 45Ca2+ uptake. These abnormal Ca2+ events and CK release were significantly prevented by Ca2+ handling drugs, tranilast, diltiazem, and FK506. The calpain inhibitor E64 prevented CK release, but not 45Ca2+ uptake. Some of these drugs (tranilast, diltiazem, and FK506) also exerted a significant protective effect for muscle degeneration in BIO14.6 hamsters and mdx mice in vivo. These observations suggest that elevated Ca2+ entry through sarcolemmal Ca2+ channels predominantly contributes to muscle degeneration and that the drugs tested here may have novel therapeutic potential against muscular dystrophy.

Animals↗

PubMed2005

Long-term outcomes for patients with solitary hepatocellular carcinoma treated by laparoscopic microwave coagulation.

BACKGROUND: Although many reports on the treatment of hepatocellular carcinoma (HCC) by microwave coagulation have been published recently, none have incorporated data for the long-term therapeutic efficacy of laparoscopic microwave coagulation (LMC). In the current study, the efficacy of LMC was assessed. METHODS: The authors performed LMC under local anesthesia in 69 previously untreated patients with solitary HCCs < or = 4.0 cm in greatest dimension. The maximum diameter for the tumors averaged 22.6 +/- 7.4 mm. Long-time survival rate was evaluated according to the size and histologic grade of the tumor. RESULTS: The 5-year overall cumulative survival rate for the 69 patients was 63.9%. The 5-year overall survival rate for patients with well differentiated HCC was 78.9%, whereas patients with moderately or poorly differentiated HCC had a 5-year overall survival rate of 38.9%. The 5-year cumulative survival rate for patients with HCCs < or = 2.0 cm in diameter was 76.0%, and 56.3% for patients with HCCs >2.0 cm. Twelve patients (17.4%) showed local tumor recurrence during the follow-up period. Local tumor recurrence was observed in 6 of 21 patients with moderately or poorly differentiated HCCs (28.6%) and in 6 of 40 patients with well differentiated HCCs (15.0%). The 3-year cancer-free survival rate for patients with well differentiated HCC was 44.4%, whereas it was 12.2% for patients with moderately or poorly differentiated HCC. CONCLUSIONS: A major factor that influenced outcome in LMC was tumor cell differentiation. LMC procedures were best suited for treatment of well differentiated HCC.

Adult↗

PubMed2005

[Laparoscopic surgery for gynecologic malignancy].

The gynecologic laparoscopic surgery that has developed in the reproductive field is performed for most cases of benign disease. Introduction of laparoscopic surgery for a gynecologic malignancy is relatively late in comparison with other surgical regions and does not qualify for insurance. An operation for a gynecologic malignancy is classified roughly into a surgery of internal pelvic organs and lymph nodes. The techniques which extensive technology is pursued involve radical hysterectomy and paraaortic lymph node excision. In the surgeons who performed many laparoscopic surgeries, it seems that a surgical procedure other than these can be performed at present. The experienced laparoscopic techniques and the particular knowledge of pelvic anatomy were necessary to perform laparoscopic surgery for gynecologic malignancy.

Female↗

PubMed2004

Calcineurin inhibits Na+/Ca2+ exchange in phenylephrine-treated hypertrophic cardiomyocytes.

The cardiac Na(+)/Ca(2+) exchanger (NCX1) is the predominant mechanism for the extrusion of Ca(2+) from beating cardiomyocytes. The role of protein phosphorylation in the regulation of NCX1 function in normal and diseased hearts remains unclear. In our search for proteins that interact with NCX1 using a yeast two-hybrid screen, we found that the C terminus of calcineurin Abeta, containing the autoinhibitory domain, binds to the beta1 repeat of the central cytoplasmic loop of NCX1 that presumably constitutes part of the allosteric Ca(2+) regulatory site. The association of NCX1 with calcineurin was significantly increased in the BIO14.6 cardiomyopathic hamster heart compared with that in the normal control. In hypertrophic neonatal rat cardiomyocytes subjected to chronic phenylephrine treatment, we observed a marked depression of NCX activity measured as the rate of Na(+)(i)-dependent (45)Ca(2+) uptake or the rate of Na(+)(o)-dependent (45)Ca(2+) efflux. Depressed NCX activity was partially and independently reversed by the acute inhibition of calcineurin and protein kinase C activities with little effect on myocyte hypertrophic phenotypes. Studies of NCX1 deletion mutants expressed in CCL39 cells were consistent with the view that the beta1 repeat is required for the action of endogenous calcineurin and that the large cytoplasmic loop may be required to maintain the interaction of the enzyme with its substrate. Our data suggest that NCX1 is a novel regulatory target for calcineurin and that depressed NCX activity might contribute to the etiology of in vivo cardiac hypertrophy and dysfunction occurring under conditions in which both calcineurin and protein kinase C are chronically activated.

Animals↗

PubMed2004

Phosphorylation of teleost phosducins and its effect on the affinity to G-protein beta gamma subunits.

Phosducin (PD) is a regulatory protein involved in the phototransduction cascade of vertebrate photoreceptor cells. We have previously demonstrated that there are rod- and cone-specific PDs (OlPD-R and OlPD-C) in the retina of the teleost fish, medaka (Oryzias latipes) [FEBS Lett. 502 (2001) 117]. A 6x His affinity precipitation assay revealed that phosphorylation by either protein kinase A (PKA) or Ca(2+)/calmodulin-dependent kinase II (CaMKII) reduced the affinity of recombinant medaka PDs to endogenous medaka G-protein beta gamma subunits (Gbetagamma). These results suggest that the affinity of medaka PDs to Gbetagamma is regulated by cAMP and Ca(2+) concentrations as also found for mammalian PDs. However, we found a specific difference in the phosphorylation patterns between recombinant OlPD-R and OlPD-C, which resulted in different affinities to Gbetagamma. These differences may affect the light/dark-adaptation between medaka rods and cones.

Animals↗

PubMed2004

Transmission electron microscopy on thin film of high density magnetic composite prepared by FIB method.

A thin specimen of a high density magnetic composite (HDMC), which is a type of powder magnetic cores was prepared for transmission electron microscopy (TEM) using a focused ion beam (FIB) method. A homogeneous thin film containing an insulator boundary between the constituent Fe powders was obtained successfully. Using this thin film, detailed flow of magnetic flux was visualized by electron holography, and the magnetic flux density was estimated to be 1.73 +/- 0.09 T being consistent with that of a bulk HDMC (1.70 T). Moreover, through Lorentz microscopy, the characteristic magnetization process of HDMC was observed by applying the magnetic field up to approximately 8 kA/m.

Holography↗

PubMed2004

Huge seminoma developed in a patient with testicular feminization.

We report a 36-year-old patient who presented with primary amenorrhea and was found to have a giant abdominal tumor. There was a family history of primary amenorrhea in her two aunts. Physical and hormonal examinations as well as chromosomal analysis led to a diagnosis of testicular feminization. The patient underwent tumorectomy along with pelvic and para-aortic lymphadectomy. The pathological diagnosis was bilateral seminoma of the testis with metastasis to para-aortic lymph nodes. Nowadays, cases of undiagnosed seminoma developing into a huge abdominal mass in patients with testicular feminization are rarely encountered, since surgical castration is generally recommended as early as possible after puberty. In testicular feminization, the risk of malignant transformation of the dysgenetic male gonads increases substantially after puberty. Early and correct diagnosis together with careful follow-up are critically important in managing testicular feminization, a rare congenital disorder.

Adult↗

PubMed2003

Classical olfactory conditioning in the cockroach Periplaneta americana.

We established a classical conditioning procedure for the cockroach, Periplaneta americana, by which odors were associated with reward or punishment. Cockroaches underwent differential conditioning trials in which peppermint odor was associated with sucrose solution and vanilla odor was associated with saline solution. Odor preference of cockroaches was tested by allowing them to choose between peppermint and vanilla sources. Cockroaches that had undergone one set of differential conditioning trials exhibited a significantly greater preference for peppermint odor than did untrained cockroaches. Memory formed by three sets of differential conditioning trials, with an inter-trial interval of 5 min, was retained at least 4 days after conditioning. This conditioning procedure was effective even for cockroaches that had been harnessed in plastic tubes. This study shows, for the first time in hemimetaborous insects, that both freely moving and harnessed insects are capable of forming olfactory memory by classical conditioning procedure. This procedure may be useful for future electrophysiological and pharmacological studies aimed at elucidation of neural mechanisms underlying olfactory learning and memory.

Animals↗

PubMed2002

Opsin expression in adult, developing, and regenerating newt retinas.

Japanese common newts (Cynops pyrrhogaster) have an ability to regenerate their neural retina even as adults. Although extensive research has been carried out attempting to understand this retinal regeneration, the molecules characterized in newt retina are limited. We isolated cDNAs encoding three putative opsins (Cp-Rh, -LWS and -SWS1), in addition to Cp-SWS2 [Takahashi et al., FEBS Lett. 501 (2001) 151-155] from a cDNA library of adult newt retina. Our immunohistochemical and in situ hybridization studies demonstrated that Cp-Rh is selectively expressed in rods, whereas the other opsins are expressed in cones. The distribution of opsin mRNAs in normal and regenerated retinas is very similar. In both developing and regenerating retinas, Cp-Rh and its mRNA first appeared in immature rods at the beginning or just after the formation of plexiform layers. Cp-Rh was initially found isotropically in the plasma membrane, and then translocalized to the apical region along with the maturation of regenerating rods. This suggests that reorganization of the intracellular structure takes place during maturation of the regenerating newt photoreceptors.

Amino Acid Sequence↗

PubMed2002

Neutralization of IFN-inducible protein 10/CXCL10 exacerbates experimental autoimmune encephalomyelitis.

We examined the effect of a monoclonal antibody (mAb) against interferon (IFN)-inducible protein 10 (IP-10)/CXCL10 on the development of experimental autoimmune encephalomyelitis (EAE) in rats induced by injecting xenogeneic brain homogenates into footpads. Treatment with neutralizing mAb against CXCL10 exacerbated EAE with increased infiltrating CD4+ cells in the central nervous system. Furthermore, the exacerbation by the mAb treatment was accompanied by less enlarged draining popliteal lymph nodes (LN) in parallel with cell number compared with those of EAE rats treated with control mAb, whereas other lymphoid organs such as the spleen and thymus were not significantly different between rats treated with anti-CXCL10 and the control mAb. Induction of gene expression of CXCL9/Mig and CXCL10 and their receptor CXCR3 was confirmed in the draining LN in EAE rats. Induction of the third CXCR3 ligand, CXCL11/I-TAC was not seen in the draining LN, whereas all three CXCR3 ligands and CXCR3 itself were markedly detected in the spinal cords following the development of EAE. These findings suggest that CXCL10 produced in the LN plays a specific inhibitory role in the development of Th1-mediated diseases such as EAE by holding sensitized and activated Th1s expressing CXCR3 in the draining LN.

Animals↗

PubMed2002

Distribution of rod- and cone-specific phosducins in retinas of non-mammalian vertebrates.

In mammalian retinas, it has been believed that just one kind of phosducin (PD) commonly exists in both rods and cones. However, we have previously reported that there are rod- and cone-specific PDs (OlPD-R and OlPD-C) in medaka (Oryzias latipes) retina [FEBS Lett., 502, 117-121, 2001]. To clarify the distribution and evolution of these photoreceptor type-specific PDs, we investigated PDs of another teleost and a reptile. Immunohistochemical and Western blot analyses using anti-medaka PD antisera demonstrated that two kinds of PDs are expressed in zebrafish (Danio rerio) photoreceptor cells. Our study is suggestive that teleosts generally possess rod- and cone-specific PDs. We isolated a cDNA encoding putative PD (PmlPD) of a diurnal gecko (Phelsuma madagascariensis longinsulae). Because diurnal gecko possesses a pure-cone retina, it was expected that PmlPD would be expressed in cones. Molecular phylogenetic analysis demonstrated that PmlPD was more closely related to mammalian PDs than teleost cone-specific PDs, suggesting that the rod- and cone-specific subtype of teleost PDs have arisen after the teleost-tetrapod divergence.

Amino Acid Sequence↗

PubMedDate not supplied

A new enucleation method for cervical myoma via laparoscopy.

Laparoscopic myomectomy was performed on five women suffering from hypermenorrhea. A new method was used which enucleated the cervical myoma from postcervical medial incision. The wound was sutured in 2 layers intracorporeally. Clipping of the uterine artery and injection of diluted vasopressin were performed to decrease bleeding during laparoscopy. This is a minimally invasive and safe procedure.

Adult↗

PubMedDate not supplied

Distribution and translocation of photoreceptor Gbetagamma-phosducin system in medaka retina.

Unlike other vertebrates, teleosts have rod- and cone-specific phosducins (PD-R and PD-C) in the retina. To evaluate the teleost Gbetagamma-PD systems, we isolated cDNAs encoding medaka Gbeta1 and GbetaC, which selectively expressed rods and cones. Immunohistochemical studies showed that the strong reactivity of GbetaC but not PD-C was detected in cone outer segments. In rod outer segments (ROS), PD-R reactivity was stronger in light-adapted retina than in dark-adapted retina. Western blot analyses of fractions torn from the cryosections showed that the PD-R concentration was low in dark-adapted ROS. It is suggested that PD-R is translocated to ROS and effectively downregulates the phototransduction cascade in light-adapted rods.

Amino Acid Sequence↗