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Biomedical subjects

Y Kawaguchi

Publications and source records attributed to Y Kawaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Successful gene therapy via intraarticular injection of adenovirus vector containing CTLA4IgG in a murine model of type II collagen-induced arthritis.

We previously constructed an adenovirus vector carrying a gene encoding a soluble form of fusion protein, consisting of the extracellular portion of cytotoxic lymphocyte antigen 4 (CTLA4) and the Fc portion of human immunoglobulin G1 (Adex1CACTLA4IgG). Murine type II collagen-induced arthritis (CIA) was treated with Adex1CACTLA4IgG. A single intraarticular injection of 1 x 10(5) PFU was able to support serum CTLA4IgG at more than 10 microg/ml for at least 12 weeks and was able to inhibit the CIA clinically and histologically. In contrast, intravenous, intramuscular, or subcutaneous injection of 1 x 10(5) PFU was unable to support a significant level of serum CTLA4IgG and thus was unable to inhibit the development of arthritis. Thus, we demonstrated that (1) a low-dose intraarticular injection of Adex1CACTLA4IgG was effective in delaying the onset of CIA and reducing the severity of arthritis; (2) an intraarticular (knee joint) injection of Adex1CACTLA4IgG effectively blocked the development of arthritis in distal paws; (3) the inhibitory effect of Adex1CACTLA4IgG lasted at least up to 20 weeks; (4) although serum CTLA4IgG at more than 10 microg/ml persisted for at least 12 weeks, mice treated by intraarticular injection of Adex1CACTLA4IgG were not anergic to adenovirus and were able to mount antibody responses against various antigens.

Abatacept↗
PubMed2001

CD40-CD40 ligand (CD154) engagement is required but not sufficient for modulating MHC class I, ICAM-1 and Fas expression and proliferation of human non-small cell lung tumors.

To determine the possible functional significance of CD40 expression on human non-small cell lung carcinomas and to assess the potential of CD40 as a therapeutic target, 18 lung tumor cell lines were established from biopsy tissues and were monitored for phenotypic changes on the cell surface and alterations in tumor cell proliferation after the ligation of CD40 with a trimeric fusion protein complex of CD40 ligand (CD40Lt). CD40 cross-linking resulted in up to a 6-fold increase in the surface expression of major histocompatibility complex (MHC) class I, Fas and intracellular adhesion molecule (ICAM)-1 in a subset of tumors expressing the highest levels of CD40. Suppression of tumor proliferation was seen after the ligation of CD40 on CD40Lt-responsive cell lines. The suppression was dose dependent, reversible and resulted from a delay of the tumor cells entering S-phase. No change in the cell phenotype or in proliferation were observed in CD40-negative tumors or in tumors expressing moderate-to-low levels of CD40 after incubation with CD40Lt. CD40-negative tumors transfected with the CD40 gene expressed high levels of CD40 on their surface, but were also unresponsive to CD40Lt cross-linking of CD40. Our data establish that CD40 is required (but not sufficient) for transducing a signal that results in phenotypic changes in human lung tumors and suppression in their proliferation. We conclude that CD40 on non-small cell lung tumors may represent a potential therapeutic target, but only on a subset of the CD40+ tumors.

Apoptosis↗
PubMed2001

Image-guided anterior thoracolumbar corpectomy: a report of three cases.

STUDY DESIGN: A report of three cases of thoracolumbar vertebral collapse treated with image-guided anterior corpectomy. OBJECTIVES: To document the surgical technique and the usefulness of image-guided anterior corpectomy for thoracolumbar vertebral collapse. SUMMARY OF BACKGROUND DATA: Computer-assisted navigation systems can provide accurate three-dimensional surgical information intraoperatively. However, there is no clinical report regarding the application and usefulness of the computer-assisted navigation system for anterior thoracolumbar corpectomy. METHODS: After exposure of anterior and lateral aspects of the vertebral bodies through the transpleural approach, a reference frame was fixed to the thoracolumbar spinous process. Then thoracolumbar corpectomy and decompression were carried out under computer assistance. RESULTS: The tip of the standard probe and the angled rongeur could be monitored on three-dimensional images during surgery, and the retropulsed fragments within the spinal canal could be safely and completely removed under computer assistance. CONCLUSION: This image-guided procedure would aid surgeons in the complete and safe decompression of thoracolumbar injury.

Aged↗
PubMed2001

Improvement in precision of the liquid chromatographic-electrospray ionization tandem mass spectrometric analysis of 3'-C-ethynylcytidine in rat plasma.

During the development of the liquid chromatography with electrospray ionization-tandem mass spectrometry for the quantitative determination of 3'-C-ethynylcytidine (I) in rat plasma, ion suppression caused by the matrix components was observed for I and its structural analogue, 3'-C-ethylcytidine (II) as the internal standard. In the method initially designed, I/II peak area ratios varied according to the degree of matrix effect, which led to the poor precision of the assay. From the examination of the ion suppression behavior for I and II, it was assumed that this phenomenon is attributed to the difference in the retention time between I and II. Based on this assumption, therefore, the methanol content in the mobile phase was changed from 5 to 25% so as to make I and II the same retention time. As a result of this modification of the initial method, the precision expressed as relative standard deviation was improved from 5.2-16.2 to 2.7-4.2% in intra-assay and from 6.8-14.9 to 3.5-7.2% in inter-assay validations.

Animals↗
PubMed2001

Role of interaction between two silkworm RecA homologs in homologous DNA pairing.

Recombinant BmRad51 and BmDmc1, silkworm homologs of the Escherichia coli RecA proteins catalyzing the homologous DNA pairing, were purified from E. coli cells carrying expression vectors. These possessed different enzymatic properties in the joint molecule formation between single-stranded circular DNA and homologous linear double-stranded DNA. The requirement of single-stranded circular DNA for the efficient reaction was twofold higher in BmRad51 than in BmDmc1. Although able to mediate the joint molecule formation independently, a complex of the two enzymes formed prior to single-stranded DNA binding was found to have augmented efficiency of the pairing reaction.

Animals↗
PubMed2001

Clinical features of extraforaminal lumbar disc herniation based on the radiographic location of the dorsal root ganglion.

STUDY DESIGN: The relations between the location of the dorsal root ganglion and pre- and postoperative symptoms were reviewed retrospectively in 27 patients who underwent radiculography and posterior discectomy. OBJECTIVES: To evaluate the clinical features and surgical outcome of extraforaminal lumbar disc herniation based on the location of dorsal root ganglion. SUMMARY OF BACKGROUND DATA: The location of dorsal root ganglia has been reported to be correlated with a variety of radicular symptoms. Extraforaminal lumbar disc herniation has several specific clinical features, one of which is severe radicular pain. However, there is no report in the literature on the association between the location of the dorsal root ganglia and the severity of the symptoms of extraforaminal lumbar disc herniation. METHODS: The radiographic location of the dorsal root ganglion of each compressed nerve root was determined by preoperative direct radiculograms. All patients were classified into the following three groups according to the location of dorsal root ganglion: intraspinal, intraforaminal, and extraforaminal. The incidences of these locations were 5 of 27 (18.5%), 15 of 27 (55.5%), and 7 of 27 (25.9%), respectively. The relation between the location of the dorsal root ganglion and clinical parameters such as the level of the compressed nerve root, the degree of limitation on straight leg raising test, the severity of the pre- and postoperative subjective symptoms (leg pain, low back pain, and walking capacity), clinical signs (sensory and motor disturbance), and the recovery rate were investigated. RESULTS: The degree of limitation on the straight leg raising test in the extraforaminal group tended to be low, compared with that in the intraspinal and intraforaminal groups. Low back pain in the extraforaminal group was more severe than that in the intraspinal and intraforaminal groups. Preoperative leg pain in the extraforaminal group was significantly more severe that that in the intraspinal group, and the walking capacity in the extraforaminal group tended to be lower than that in the intraspinal and intraforaminal groups. No significant differences were found between the location of dorsal root ganglion and the preoperative sensory or motor disturbance and surgical outcomes. CONCLUSION: The location of the dorsal root ganglion might influence the severity of radicular symptoms (pain and walking distance tolerance) in patients with extraforaminal lumbar disc herniation.

Adult↗
PubMed2001

Herpes simplex virus 1 alpha regulatory protein ICP0 functionally interacts with cellular transcription factor BMAL1.

The infected cell protein no. 0 (ICP0) of herpes simplex virus 1 (HSV-1) is a promiscuous transactivator shown to enhance the expression of gene introduced into cells by infection or transfection. At the molecular level, ICP0 is a 775-aa ring finger protein localized initially in the nucleus and late in infection in the cytoplasm and mediates the degradation of several proteins and stabilization of others. None of the known functions at the molecular level account for the apparent activity of ICP0 as a transactivator. Here we report that ICP0 functionally interacts with cellular transcription factor BMAL1, a member of the basic helix-loop-helix PER-ARNT-SIM (PAS) super family of transcriptional regulators. Specifically, sequences mapped to the exon II of ICP0 interacted with BMAL1 in the yeast two-hybrid system and in reciprocal pull-down experiments in vitro. Moreover, the enhancement of transcription of a luciferase reporter construct whose promoter contained multiple BMAL1-binding sites by ICP0 and BMAL1 was significantly greater than that observed by ICP0 or BMAL1 alone. Although the level of BMAL1 present in nuclei of infected cells remained unchanged between 3 and 8 h after infection, the level of cytoplasmic BMAL1 was reduced at 8 h after infection. The reduction of cytoplasmic BMAL1 was significantly greater in cells infected with the ICP0-null mutant than in the wild-type virus-infected cells, suggesting that ICP0 mediates partial stabilization of the protein. These results indicate that ICP0 interacts physically and functionally with at least one cellular transcription-regulatory factor.

ARNTL Transcription Factors↗
PubMed2001

The conserved domain CR2 of Epstein-Barr virus nuclear antigen leader protein is responsible not only for nuclear matrix association but also for nuclear localization.

There is a growing body of evidence for the importance of the nuclear matrix in various nuclear events including gene expression and DNA replication. Epstein-Barr virus (EBV) nuclear antigen leader protein (EBNA-LP) is a nuclear matrix-associated protein that has been suggested to play an important role in EBV-induced transformation. To define the biological significance of the association of EBNA-LP with the nuclear matrix, we mapped the domain of EBNA-LP responsible for nuclear matrix association and investigated the functions of the EBNA-LP mutant mutagenized by substitution of alanines for the cluster of arginine residues in the mapped region. The results of the present study were as follows. (i) Transiently expressed EBNA-LP in COS-7 or BOSC23 cells was associated with the nuclear matrix, similarly to that in EBV-infected B cells. (ii) Mutational analysis of EBNA-LP revealed that a 10-amino acid segment of EBNA-LP is critical for nuclear matrix association of the protein. Interestingly, the identified region overlapped with the region CR2 of EBNA-LP conserved among a subset of primate gammaherpesviruses. The identified segment is referred to as EBNA-LP NMTS (nuclear matrix targeting signal). (iii) The EBNA-LP mutant with the arginine to alanine substitutions in NMTS was no longer localized not only to the nuclear matrix but also to the nucleus. (iv) The EBNA-LP mutant lacked its ability to coactivate EBNA-2-dependent transactivation. These results indicated that EBNA-LP needs to be localized in the nucleus and/or associated with the nuclear matrix through CR2 to elicit its function such as the coactivation of the EBNA-2-dependent transcriptional activation.

Alanine↗
PubMed2001

Variants of neurogenin 3 gene are not associated with Type II diabetes in Japanese subjects.

AIMS/HYPOTHESIS: Neurogenin 3 (ngn3) is a transcription factor expressed in the endocrine precursor cells of the pancreas. It has recently been reported that ngn3-deficient mice show absence of pancreatic endocrine cells and die of postnatal diabetes. The purpose of this investigation was to screen for polymorphisms of the ngn3 gene and to test whether these polymorphisms are associated with Type II (non-insulin-dependent) diabetes mellitus in the Japanese subjects. METHODS: We screened ngn3 gene and upstream region by direct sequencing and estimated the prevalence of polymorphisms in 197 patients with Type II (non-insulin-dependent) diabetes mellitus and 216 control subjects. RESULTS: We identified four novel polymorphisms, Ser199Phe (596C/T), -43insCA, -983C/T and -1822G/A. In an association study the allelic frequencies of the major allele of these four polymorphisms were 0.721, 0.914, 0.912 and 0.530 in diabetic patients, respectively, and 0.694, 0.905, 0.917 and 0.537 in control subjects, respectively. CONCLUSION/INTERPRETATION: Mutations and polymorphisms of ngn3 gene are not significantly associated with Type II (non-insulin-dependent) diabetes mellitus in the Japanese subjects.

Aged↗
PubMed2001

Prediction of neurologic outcome in patients with spinal cord injury by using hyperbaric oxygen therapy.

The effectiveness of hyperbaric oxygen therapy (HBO) in predicting neurological recovery in patients with spinal cord injury was evaluated. HBO has been used to treat spinal cord injury, but HBO does not appear to greatly alter the neurological outcome. This is the first report of the use of HBO as a diagnostic tool to evaluate neurological recovery after spinal cord injury. The study group consisted of 22 patients, aged 21-73 years, with spinal cord injuries. The effect of HBO was evaluated on admission and categorized as one of four grades (excellent, good, fair, or poor). The neurological status was evaluated on admission and at the time of follow-up, according to Frankel grade and the American Spinal Injury Association (ASIA) motor score. Correlations between the HBO effect and Frankel grade recovery and correlations between the HBO effect and recovery rate of the ASIA motor score were evaluated. The recovery in Frankel grade from admission to the final follow-up became better as the effectiveness of HBO increased (r = 0.445; P = 0.0414). The Frankel grade (r = 0.036; P = 0.871) and ASIA motor score (r = 0.029; P = 0.893) on admission did not correlate with the recovery in Frankel grade. There was a significant correlation between the HBO effect and the recovery rate of the ASIA motor score (r = 0.586; P = 0.0072), but this correlation was weaker than that for the ASIA motor score on admission (r = 0.752; P = 0.0006). We conclude that HBO can be employed to assess the status of spinal cord function recovery after spinal cord injury.

Adult↗
PubMed2001

Mapping and promoter sequencing of HNF-1beta gene in diabetes-prone and -resistant mice.

By using a novel single nucleotide polymorphism (SNP) in the coding sequence, the chromosomal location of Tcf2, encoding hepatic nuclear factor (HNF)-1beta, was determined in F2 intercrosses between Nagoya-Shibata-Yasuda (NSY) mice, an animal model of type 2 diabetes, and control C3H/He mice. The promoter region of Tcf2 gene was sequenced in NSY, non-obese diabetic (NOD) and control C3H/He mice. Tcf2 was mapped between genetic markers D11MIT320 and D11MIT195 with the following distances: D11MIT320-(7.3 cM)-Tcf2-(0.5 cM)-D11MIT195. A variant with insertion of C between -205 and -204 in the promoter region of Tcf2 was identified in NSY mice, but not NOD and C3H/He mice.

Animals↗
PubMed2001

Polymorphism in gene for islet autoantigen, IA-2, and type 1 diabetes in Japanese subjects.

Autoantibodies against IA-2 have been detected in up to 86% of newly diagnosed patients with type 1 diabetes and appear to identify a subgroup of prediabetic subjects who rapidly progress to type 1 diabetes. We examined the association of IA-2 gene polymorphism with type 1 diabetes in Japanese subjects. A total of 276 Japanese subjects were studied for disease association and, in addition, another 53 patients were studied for association with the autoantibody status to IA-2. A microsatellite marker D2S1753E, located in the intron of the IA-2 gene, was used as a genetic marker in this study. In Japanese, two alleles (161mu and 165mu) were more frequent, and the 163mu allele was less frequent than in Caucasians (p = 0.0001). There was no significant difference in frequencies of alleles between diabetic patients and control subjects. The frequency of IA-2 gene polymorphism was not significantly different between patients stratified by age-at-onset, or between patients with and without susceptible HLA, DRB1*0405, DRB1*0802 and DRB1*0901. There was no significant difference in allele frequency of the IA-2 gene polymorphism between patients with and without autoantibody to IA-2. In conclusion, IA-2 gene polymorphism is not associated with either susceptibility to, or heterogeneity in type 1 diabetes in Japanese subjects.

Alleles↗
PubMed2001

Slow synchronized bursts of inhibitory postsynaptic currents (0.1-0.3 Hz) by cholinergic stimulation in the rat frontal cortex in vitro.

Cholinergic inputs from the basal forebrain to cortex exert profound effects on cortical activities, such as a rhythmic synchronization. For these modulatory effects inhibitory interneurons could play crucial roles within the cortical circuitry. To study cholinergic modulation of GABA-mediated inhibition, we recorded inhibitory postsynaptic current (IPSC) during application of cholinergic agonists in the rat frontal cortex in vitro. Both carbachol and muscarine caused two temporally different patterns of IPSC modulation in both pyramidal cells and inhibitory interneurons: tonic or periodic increase of GABA-A receptor-mediated inhibition. The tonic pattern showed a continuous increase of IPSC frequency, while the periodic increase manifested itself as rhythmic (0.1-0.3 Hz, mean 0.2 Hz) bursts of IPSC (frequency: 6-69 Hz, mean 24 Hz; burst duration: 1.2-4.3 s, mean 2.2 s). Both types of increase were suppressed by atropine or pirenzepine, muscarinic-receptor antagonists. The periodical IPSC bursts were not affected by antagonists for ionotropic glutamate receptors. Following cholinergic stimulation, periodic IPSC bursts in nearby cells were synchronized as a whole, but individual inhibitory events within the bursts were not always temporally correlated, suggesting synchronized depolarizations of several presynaptic interneurons. It has been revealed that slow rhythmic depolarizations accompanying spike firing can be generated within the cortex. In addition to this periodic excitation of cortical circuits, these results indicate that cortical inhibitory interneurons have their own acetylcholine-dependent mechanism generating the slow rhythm independent of the excitatory circuits.

Acetylcholine↗
PubMed2001

Effect of a selective Abl tyrosine kinase inhibitor, STI571, on in vitro growth of BCR-ABL-positive acute lymphoblastic leukemia cells.

By employing a new semi-quantitative assay system that includes co-culturing leukemia cells with the mouse bone marrow-derived stromal cell line MS-5, we examined the suppressive effect of a selective inhibitor of ABL tyrosine kinase, STI571, on acute lymphoblastic leukemia (ALL) cells with BCR-ABL fusion. Leukemic blast cells from eight patients with B-precursor ALL, including three patients with BCR-ABL-positive ALL, were cultured on monolayers of MS-5 cells for 3 weeks with or without addition of variable amounts of STI571. In all cases, cobblestone areas (CAs) were formed, showing clear linear cell dose-dependent curves, allowing quantitative assessment of blast cell growth. The progenitor frequencies obtained by this direct CA-forming cell (CAFC) assay were equivalent to ALL progenitor frequencies assessed by the standard limiting dilution assay. The number of CAFCs ranged from 12.3 to 140.3/10(4) cells. In BCR-ABL-positive ALL patients, CA-containing cells were examined by FISH, and all contained BCR-ABL fusion genes. STI571 inhibited CA formation of BCR-ABL-positive ALL cells virtually 100% at 0.1-1.0 micromol/l. None of the five BCR-ABL-negative ALL patients showed this growth inhibition by STI571 at 0.1-1.0 micromol/l. Our results indicate that STI571 selectively inhibits in vitro growth of BCR-ABL-positive ALL cells.

Adolescent↗
PubMed2001

Kit(+) melanocytes seem to contribute to melanocyte proliferation after UV exposure as precursor cells.

Melanogenesis caused by UV exposure is characterized by proliferation and differentiation of functioning melanocytes in epidermis. Recently, the existence of precursor melanocytes in normal skin was proposed immunohistochemically. Thus, this precursor melanocyte seems to proliferate and differentiate into mature pigmented melanocytes after UV exposure. To elucidate how these processes occur, we examined C57BL mouse epidermal sheets after UV exposure immunohistochemically. In normal epidermis, TRP-1(+) cells and Kit(+) cells were easily identified and the cellularities were 41.0 and 31.7 cells per mm(2), respectively. Only a few Mitf(+) cells and no TRP-2(+) cells were observed. On the first day after UV exposure, Mitf(+) cells and TRP-2(+) cells appeared, whereas the numbers of TRP-1(+) cells and Kit(+) cells decreased. Some Kit+ cells also expressed Mitf, but no TRP-1 and Mitf double positive cells were seen. In this period, some Mitf(+) cells were labeled with BrdU. The next day, Mitf(+) cells and TRP-2(+) cells increased to the maximum cellularity, and they decreased thereafter and disappeared on the seventh day. An increase of TRP-1(+) cells was first identified on the fifth day after UV exposure, and reached a cellularity four times as great as that of the normal control on the fourteenth day. The subepidermal injection of Kit antibody attenuated the increase of Mitf+ cells and TRP-1(+) cells. These findings suggested that precursor cells that reside in the skin, first differentiated into Mitf(+) and TRP-2(+) melanocytes by the activation of the Kit receptor, then become mature TRP-1(+) melanocytes after UV exposure.

Animals↗
PubMed2001

Mechanism of intramedullary high intensity area on T2-weighted magnetic resonance imaging in osteoid osteoma: a possible role of COX-2 expression.

To study the mechanism and pathophysiology of the development of intramedullary high intensity areas on T2-weighted magnetic resonance images (MRI) in cases of osteoid osteoma, we examined the expression of cyclooxygenase-2 (COX-2) in the nidus and surrounding bone tissues. In all six cases showing a marked intramedullary high intensity area adjacent to the nidus before surgery, neoplastic osteoblasts inside the nidus showed strong and diffuse COX-2 immunoreactivity. On the other hand, the osteoblasts rimming the surrounding reactive bone were COX-2 negative. In two cases examined by reverse transcription-polymerase chain reaction (RT-PCR), COX-2 mRNA was detected in abundance in the nidus. Histologically, vascular dilatation together with intramedullary edema was observed in all cases, which was probably reflected as a high intensity area on T2-weighted MRI. From our study, a high level of COX-2 expression in neoplastic osteoblasts in the nidus of osteoid osteomas may cause the secondary changes depicted by MRI.

Adolescent↗
PubMed2001

Insulin secretion to glucose as well as nonglucose stimuli is impaired in spontaneously diabetic Nagoya-Shibata-Yasuda mice.

To clarify the mechanisms of impaired insulin secretion in Nagoya-Shibata-Yasuda (NSY) mice, an inbred strain of mice with spontaneous development of type 2 (non-insulin-dependent) diabetes mellitus, the insulin response to glucose (5.5 to 27.8 mmol/L) and nonglucose stimuli (glibenclamide, arginine, and BayK8644, a Ca-channel opener) was studied in vitro using isolated islets from male NSY and control C3H/He mice at 36 weeks of age by the batch incubation method. Insulin response to 5.5 mmol/L glucose was not significantly different between NSY and C3H/He mice, but insulin response to a high concentration of glucose (> or = 11.1 mmol/L) was significantly smaller in NSY mice than in control C3H/He mice. The dose-response curve of insulin secretion showed a markedly reduced maximum response, but almost normal glucose sensitivity in NSY islets. Insulin responses to glibenclamide (1 mmol/L), arginine (20 mmol/L), and BayK8644 (0.1 mmol/L) were also significantly smaller in NSY mice than in C3H/He mice. Insulin content of islets, in contrast, was significantly higher in NSY mice than in C3H/He mice. The impaired insulin response to glucose and nonglucose stimuli together with higher insulin content in islets in the NSY mouse suggest that a defect in voltage-dependent Ca(2+)-channel or thereafter in the cascade of insulin secretion may be responsible for impaired insulin secretion in NSY mice. NSY mice, therefore, could be a novel animal model of type 2 diabetes with a defect in insulin secretion at a different site from that in previously known animal models.

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