Biomedical subjects

T Kohno

Publications and source records attributed to T Kohno.

At least 19 recordsLinked to original sources

PubMed2000

Brain-derived neurotrophic factor requirement for activity-dependent maturation of glutamatergic synapse in developing mouse somatosensory cortex.

The maturation of cortical circuitry critically depends on experience. Recently, a model of silent synapse has been proposed as a mechanism of activity-mediated transition of immature synapse to mature synapse. It is not clear, however, how activity could regulate this transition. Here, we show the evidence that endogenous brain-derived neurotrophic factor (BDNF) is required for the maturation of glutamatergic synapse in developing mouse somatosensory cortex. Field potential recordings of thalamocortical glutamatergic synaptic activity with brain slices from the BDNF mutant mice showed that AMPA receptor responses are low, but NMDA receptor responses remain high in layer 4, thus, the relative contribution of AMPA receptor response is significantly lower compared to the age-matched wild-type mouse. Furthermore, optical images of development of thalamocortical connectivity with a voltage-sensitive dye showed that NMDA receptor-dominant synapse is established first in layer 4 and layer 5/6 then AMPA receptor response appears later in concomitant with reduction of NMDA receptor response in layer 4 and that the maturation of the silent synapse is impaired in the BDNF mutant mice. In layer 5/6, NMDA receptor response was suppressed without upregulation of AMPA receptor response. This process also required BDNF function. Interestingly, whisker-trimming of the wild-type mouse from just after birth showed quite similar results with the homozygous mutant of their whiskers left intact. Therefore, we would propose that BDNF is a critical mediator for the maturation of glutamatergic synapse in developing mouse somatosensory cortex.

Animals↗

PubMed2000

Antibody against a novel, myriocin (ISP-I)-based immunosuppressant, FTY720.

An antibody was prepared by immunizing rabbits with an ovalbumin conjugate of 2-amino-2-(2-(4-(4-mercaptobutyl)phenyl)ethyl)propane-1,3-diol HCl (AMPD-4), which contains the essential structure of the novel immunosuppressant FTY720. As the antibody reacted to not only AMPD-4, but also FTY720, it should be useful for immunoassay of FTY720 in body fluids, tissues and cells.

Animals↗

PubMed2000

Somatic mutations and genetic polymorphisms of the PPP1R3 gene in patients with several types of cancers.

Recently, we found nonsense and missense mutations of the PPP1R3 (protein phosphatase 1, regulatory subunit 3) gene in diverse human cancer cell lines and primary lung carcinomas, indicating that PPP1R3 functions as a tumor suppressor in human carcinogenesis. In this study, to assess the prevalence of PPP1R3 mutations in human primary cancers and the genetic diversity of the PPP1R3 gene in the human population, somatic mutations and genetic polymorphisms in the PPP1R3 gene were examined in 137 pairs of cancerous and non-cancerous tissues of patients with cancers of colon, ovary, and liver. Five somatic mutations including two missense mutations were detected in three cancerous tissues consisting of two colorectal carcinomas and one ovarian carcinoma. Five novel single nucleotide polymorphisms (SNPs) associated with the substitution of amino acids were also identified in cancer patients, in addition to five known nonsynonymous SNPs, including three previously reported ones as having an impact on the susceptibility to insulin resistant disorders. Differences in the activities and properties of multiple PPP1R3 proteins, which are produced in human cells due to variable somatic mutations and genetic polymorphisms in the PPP1R3 gene, can be involved in human carcinogenesis and susceptibility to diseases.

Amino Acid Substitution↗

PubMed2000

Combinatorial synthesis of omega-conotoxin MVIIC analogues and their binding with N- and P/Q-type calcium channels.

Omega-conotoxin MVIIC (MVIIC) blocks P/Q-type calcium channels with high affinity and N-type calcium channels with low affinity, while the highly homologous omega-conotoxin MVIIA blocks only N-type calcium channels. We wished to obtain MVIIC analogues more selective for P/Q-type calcium channels than MVIIC to elucidate structural differences among the channels, which discriminate the omega-conotoxins. To prepare a number of MVIIC analogues efficiently, we developed a combinatorial method which includes a random air oxidation step. Forty-seven analogues were prepared in six runs and some of them exhibited higher selectivity for P/Q-type calcium channels than MVIIC in binding assays.

Amino Acid Sequence↗

PubMed2000

Allelic imbalance and mutations of the PTEN gene in ovarian cancer.

The PTEN/MMAC1/TEP1 tumor-suppressor gene, which maps to chromosome 10q23.3, is mutated and homozygously deleted in a variety of human tumors, including endometrioid-type ovarian tumors. We examined 33 primary ovarian cancers and 3 ovarian borderline tumors for allelic imbalance (AI) of the 10q23.3 region using 5 polymorphic markers, including an insertion/deletion-type polymorphic marker identified in intron 4 of the PTEN gene. AI at one or more loci was detected in 12 of 31 (39%) informative ovarian cancers and none of 3 ovarian borderline tumors. The commonly deleted region was mapped between the D10S215 and D10S541 loci, including the PTEN locus. Moreover, the incidence of AI at the PTEN locus (38%) was the highest among the 5 loci examined. Therefore, we searched for mutations in the entire coding region of the PTEN gene by PCR-SSCP and sequencing analyses in these tumors and 7 ovarian cancer cell lines. Mutations were detected in 3 of the 33 (9%) ovarian cancers: 2 cases with double mutations and 1 case with a mutation on 1 allele accompanied by deletions on both alleles in the poly T tract preceding the splice acceptor site in intron 7. An intragenic deletion was detected in 1 of the 7 (14%) ovarian cancer cell lines. PTEN mutations were detected not only in the endometrioid type but also in the serous and mucinous types of ovarian cancer. However, PTEN was not mutated in the 12 tumors that showed AI of the PTEN locus. Our results suggest that the PTEN gene plays an important role in the development of a subset but diverse histological types of ovarian tumors. However, it is possible that another tumor-suppressor gene in the close vicinity of the PTEN gene is also inactivated by AI of the 10q23.3 region.

Chromosome Mapping↗

PubMed2000

Results from surgical treatment for thymoma. 43 years of experience.

OBJECTIVE: The biological behavior of thymoma and its prognosis after surgical intervention remain still controversial. The efficacy of surgical treatment for thymoma was investigated by examining long-term follow-up data. SUBJECTS AND METHODS: Follow-up data for patients undergoing surgical resection of histopathologically-confirmed thymoma between 1954 and 1997 were obtained and were retrospectively analyzed. Clinical staging was based on Masaoka's staging system, and histological classification on Rosai's proposed criteria. RESULTS: Data for 140 patients were collected. Sixty-four patients had stage I, 32 had stage II, 28 had stage III, and 16 had stage IV thymoma. There were significant differences in survival between patients with stage I and stage III, stage I and stage IV and stage II and stage III disease, but not between those with stage I thymoma and stage II thymoma. No significant difference in survival was observed between the 56 patients with myasthenia gravis (MG) and the 84 without MG. The 38 patients classified as having a predominantly-epithelial thymoma had a poorer prognosis than the 41 with a predominantly-lymphocytic thymoma. Until 1975, there were four patients with stage I thymomas who later showed recurrence, compared with 21 among those with stage II, III and IV diseases. Since 1976, extended thymectomy with thymomectomy under median sternotomy has been adopted as the standard operation for a thymoma, and there has been no recurrence in stage I patients. CONCLUSIONS: Patients with stage III or IV invasive thymoma have a poorer prognosis and a higher recurrence rate than those with encapsulated thymoma, and patients with a predominantly-epithelial thymoma have a poorer prognosis than those with a predominantly-lymphocytic thymoma. Extended thymectomy with thymomectomy under median sternotomy can be considered as adequate treatment for a stage I thymoma. Myasthenia gravis does not appear to affect the prognosis of patients with a thymoma.

Adult↗

PubMed2000

Indocyanine green angiography in Sorsby's fundus dystrophy.

PURPOSE: To report the indocyanine green angiographic findings in patients with a fundus dystrophy characterized by subretinal deposits, macular atrophic or neovascular degeneration and peripheral chorioretinal atrophy which is most likely Sorsby's fundus dystrophy. METHODS: A series of 11 clinically affected patients and 4 asymptomatic carriers, belonging to one autosomal dominant pedigree were examined with stereoscopic funduscopy, fluorescein and indocyanine green angiography. RESULTS: Subretinal deposits were found in 20 eyes of 10 patients. These deposits stained slightly on indocyanine green angiography, causing a reticular pattern. Two eyes had a disciform lesion and 3 geographic atrophy in the macula. A peripheral disciform lesion was found in 1 eye. Indocyanine green angiography identified peripapillary choroidal neovascularization in 2 eyes. Peripheral chorioretinal atrophy was found in 8 eyes of 4 patients, associated with peripheral plaques that could only be identified by indocyanine green angiography in 6 eyes of 3 patients. CONCLUSION: Indocyanine green angiography in Sorsby's fundus dystrophy may indicate the presence of homogeneously staining, well-demarcated peripheral areas of hyperfluorescence associated with chorioretinal atrophy. These plaques correspond in our opinion to choroidal neovascularization which is otherwise unsuspected.

Adult↗

PubMed2000

Indocyanine green angiographic features of choroidal rupture and choroidal vascular injury after contusion ocular injury.

PURPOSE: To report features of choroidal rupture and choroidal vascular injury after contusion ocular injury on indocyanine green angiography. METHODS: In a prospective study, nine patients (nine eyes) with choroidal rupture after ocular contusion underwent initial fluorescein angiography and indocyanine green angiography within 19 days after trauma. Eyes that had a distinct abnormality of the retinal pigment epithelium were excluded from this study. Subtraction indocyanine green angiography was also performed. Follow-up fluorescein angiographic and indocyanine green angiographic findings were also studied. RESULTS: Initial ophthalmoscopic examination revealed subretinal hemorrhage in all nine eyes. In five of the nine eyes, choroidal rupture was not seen on initial ophthalmoscopic or fluorescein angiographic examination because it was hidden beneath the subretinal hemorrhage, but it was detected on subsequent examinations. In the remaining four eyes, choroidal rupture was observed by ophthalmoscopy at the time of initial examination, and these eyes exhibited hyperfluorescent streaks on fluorescein angiography in the region of the subretinal hemorrhage. On initial indocyanine green angiography of all nine eyes, observed hypofluorescent streaks became more obvious with time. For each eye, there were more hypofluorescent streaks on indocyanine green angiography than hyperfluorescent streaks on fluorescein angiography. In one eye, the location of indocyanine green leakage nearly coincided with the location of a hyperfluorescent streak on fluorescein angiography. In this case, crescentic streaks of hypofluorescence were seen on the temporal side of the subretinal hemorrhage on indocyanine green angiography, although choroidal rupture was not observed in that region by ophthalmoscopy or fluorescein angiography. In two of the nine eyes, indocyanine green angiography and the subtraction technique demonstrated disturbance of flow into choroidal vessels, especially at the choroidal rupture site. CONCLUSION: After ocular contusion injury, various features of choroidal rupture and choroidal vascular injury were observed on indocyanine green angiography. This technique may contribute to the diagnosis of choroidal rupture and to the understanding of the clinical course after injury.

Accidents, Traffic↗

PubMed2000

Frequent microsatellite instability and BAX mutations in T cell acute lymphoblastic leukemia cell lines.

Allelic status of the BAT26 and BAT25 loci was examined in 117 leukemia/lymphoma cell lines consisting of 44 B-lymphoid lineage cell lines, 30 T-lymphoid cell lines and 43 myeloid cell lines to define the lineage specificity of microsatellite instability (MSI) in hematological malignancies. Seventeen (15%) cell lines were defined as having MSI. The incidence of MSI was significantly (P < 0.01) higher in cell lines of lymphoid lineage (15/74; 20%) than in those of myeloid lineage (2/43; 5%). In the cell lines of lymphoid lineage, the incidence of MSI in T cell acute lymphoblastic leukemia (T-ALL) (11/30; 37%) was significantly (P < 0.01) higher than those in B-lineage malignancies (4/44; 9%). The 17 cell lines with MSI were subjected to the mutation analysis of the coding microsatellites in 13 candidate genes. Frameshift mutations were most frequently detected in the BAX gene (14/17, 82%), while the hMSH3, hMSH6, TGFbetaRII, DRP and IGFIIR genes were less frequently mutated (24-47%). The present result indicates that MSI is involved in the development and/or progression of lymphoid malignancies, especially of T-ALL, through the inactivation of BAX and several other genes.

Gene Frequency↗

PubMed2000

Disinfection potential of electrolyzed solutions containing sodium chloride at low concentrations.

Electrolyzed products of sodium chloride solution were examined for their disinfection potential against hepatitis B virus (HBV) and human immunodeficiency virus (HIV) in vitro. Electrolysis of 0.05% NaCl in tap water was carried out for 45 min at room temperature using a 3 A electric current in separate wells installed with positive and negative electrodes. The electrolyzed products were obtained from the positive well. The oxidation reduction potential (ORP), pH and free chlorine content of the product were 1053 mV, pH 2.34 and 4.20 ppm, respectively. The products modified the antigenicity of the surface protein of HBV as well as the infectivity of HIV in time- and concentration-dependent manner. Although the inactivating potential was decreased by the addition of contaminating protein, recycling of the product or continuous addition of fresh product may restore the complete disinfection against bloodborne pathogens.

Acids↗

PubMed2000

Norepinephrine facilitates inhibitory transmission in substantia gelatinosa of adult rat spinal cord (part 2): effects on somatodendritic sites of GABAergic neurons.

BACKGROUND: It has been reported previously that norepinephrine, when applied to the spinal cord dorsal horn, excites a subpopulation of dorsal horn neurons, presumably inhibitory interneurons. In the current study, the authors tested whether norepinephrine could activate inhibitory interneurons, specifically those that are "GABAergic." METHODS: A transverse slice was obtained from a segment of the lumbar spinal cord isolated from adult male Sprague-Dawley rats. Whole-cell patch-clamp recordings were made from substantia gelatinosa neurons using the blind patch-clamp technique. The effects of norepinephrine on spontaneous GABAergic inhibitory postsynaptic currents were studied. RESULTS: In the majority of substantia gelatinosa neurons tested, norepinephrine (10-60 microM) significantly increased both the frequency and the amplitude of GABAergic inhibitory postsynaptic currents. These increases were blocked by tetrodotoxin (1 microM). The effects of norepinephrine were mimicked by the alpha1-receptor agonist phenylephrine (10-80 microM) and inhibited by the alpha1-receptor-antagonist WB-4101 (0.5 microM). Primary-afferent-evoked polysynaptic excitatory postsynaptic potentials or excitatory postsynaptic currents in wide-dynamic-range neurons of the deep dorsal horn were also attenuated by phenylephrine (40 microM). CONCLUSION: The observations suggest that GABAergic interneurons possess somatodendritic alpha1 receptors, and activation of these receptors excites inhibitory interneurons. The alpha1 actions reported herein may contribute to the analgesic action of intrathecally administered phenylephrine.

Adrenergic alpha-1 Receptor Agonists↗

PubMed2000

Actions of midazolam on GABAergic transmission in substantia gelatinosa neurons of adult rat spinal cord slices.

BACKGROUND: Although intrathecal administration of midazolam has been found to produce analgesia, how midazolam exerts this effect is not understood fully at the neuronal level in the spinal cord. METHODS: The effects of midazolam on either electrically evoked or spontaneous inhibitory transmission and on a response to exogenous gamma-aminobutyric acid (GABA), a GABA(A)-receptor agonist, muscimol, or glycine were evaluated in substantia gelatinosa neurons of adult rat spinal cord slices by using the whole-cell patch-clamp technique. RESULTS: Bath-applied midazolam (1 microM) prolonged the decay phase of evoked and miniature inhibitory postsynaptic currents (IPSCs), mediated by GABA(A) receptors, without a change in amplitudes, while not affecting glycine receptor-mediated miniature inhibitory postsynaptic currents in both the decay phase and the amplitude. Either GABA- or muscimol-induced currents were enhanced in amplitude by midazolam (0.1 microM) in a manner sensitive to a benzodiazepine receptor antagonist, flumazenil (1 microM); glycine currents were, however, unaltered by midazolam. CONCLUSIONS: Midazolam augmented both the duration of GABA-mediated synaptic current and the amplitude of GABA-induced current by acting on the GABA(A)-benzodiazepine receptor in substantia gelatinosa neurons; this would increase the inhibitory GABAergic transmission. This may be a possible mechanism for antinociception by midazolam.

2-Amino-5-phosphonovalerate↗

PubMed2000

Expression of the OGG1-type 1a (nuclear form) protein in cancerous and non-cancerous human cells.

The human OGG1 gene encodes 8-hydroxyguanine DNA glycosylase. By RT-PCR analysis, five novel type 1 transcripts, in addition to eight known types (OGG1-types 1a to 1c and 2a to 2e), were identified. Among them, only the type 1a isoform contains both a nuclear localization signal and the entire DNA binding motif, suggesting the involvement of type 1a in chromosomal DNA repair. By Western blot analysis using a monoclonal antibody prepared by immunizing the whole type 1a protein, a 39 kDa type 1a protein was detected in lung cancer cell lines and peripheral lymphocytes. The type 1a protein was expressed at a similar level, irrespective of its polymorphic types characterized by distinct repair activity. By an immunocytochemical study, the majority of type 1a protein was localized in the nucleus. These results indicate that OGG1-type 1a protein is involved in the repair of 8-hydroxyguanine in chromosomal double-stranded DNA and constitutively expressed in cancerous and non-cancerous human cells.

3T3 Cells↗

PubMed2000

Two regions of homozygous deletion clusters at chromosome band 9p21 in human lung cancer.

We examined 149 lung cancer cell lines for homozygous deletions using 24 DNA markers, which were mapped and ordered in chromosome band 9p21, to define the target regions for 9p21 deletions in human lung cancer. Homozygous deletions were detected in 39 (26%) cell lines and clustered at 2 independent regions. One was the region containing the p16/CDKN2A tumor suppressor gene, and this region was deleted in 32 (21%) cell lines. The other was the region containing D9S171, which is the locus approximately 3 Mb proximal to the CDKN2A locus. This region, designated as the D9S171 region, was deleted in 18 (12%) cell lines. Seven of the 18 cell lines had identical minimum deletions of a 17,036 bp sequence located 20 kb distal to the D9S171 locus. However, such a deletion was also observed in the corresponding B-lymphoblastoid cell line from 1 of the 7 cell lines and in 5 (16%) of 32 noncancerous tissues, suggesting that the deletion was a genetic polymorphism. By considering this polymorphism, 11 (7%) cell lines still had deletions at the D9S171 region. Two NSCLC cell lines showed deletions at the D9S171 region and retentions of the CDKN2A locus. Furthermore, an NSCLC cell line showed discontinuous deletions including either the CDKN2A or D9S171 locus. Therefore, the region surrounding the D9S171 locus was defined as another target region for the 9p21 deletions. It is possible that unknown tumor suppressor gene(s) are present in this chromosomal region. Genes Chromosomes Cancer 27:308-318, 2000.

Carcinoma, Non-Small-Cell Lung↗

PubMed2000

Phase I/II trial of recombinant methionyl human tumor necrosis factor binding protein PEGylated dimer in patients with active refractory rheumatoid arthritis.

OBJECTIVE: To evaluate the safety, immunogenicity, pharmacokinetics, and efficacy of intravenous administration of tumor necrosis factor binding protein (TNFbp) dimer in patients with rheumatoid arthritis (RA). METHODS: This phase I/II study was a multicenter, randomized, double blind, placebo controlled, ascending dose study evaluating TNFbp dimer administered by i.v. infusion. Thirty-three patients with RA divided into 3 cohorts received TNFbp dimer (30, 100, 300 microg/kg) or placebo during a 5 min infusion at baseline and at 3 and 6 weeks; patients were followed at routine intervals after each infusion through 77 days postinfusion. Pharmacokinetics were analyzed using a log-linear regimen and comparisons were made between half-life after first, 2nd, and 3rd doses. Plasma TNFbp dimer concentrations and serum antibody levels were used in the measurement of pharmacokinetics. RESULTS: Administration of 30 microg/kg of TNFbp dimer was generally well tolerated; the maximum tolerated dose was 100 microg/kg. No serious adverse events were reported. A significant antibody response affected the half-life and clearance of TNFbp dimer at each dose group. Anti-TNFbp antibodies were noncytotoxic and nonagonistic. Clinical evaluations provided evidence of in vivo activity of TNFbp dimer in these patients. CONCLUSION: TNFbp dimer administered to patients with long standing RA resulted in significant antibody production to the study drug. This effect reduced the half-life and clearance of the TNFbp. This TNFbp will not be a viable option for treating patients with RA secondary to immunogenicity.

Adult↗

PubMed2000

[Primary mediastinal germ cell tumor: report of a case].

Fourty-seven years old male was admitted to this hospital with the symptoms of worsening cough and chest pain. An anterior mediastinal tumor, 13 cm in diameter, was pointed out on chest X-ray. The tumor was diagnosed as primary mediastinal germ cell tumor with mixed seminomatous and non-seminomatous elements due to elevated serum AFP and beta HCG, and the pathological finding of needle biopsy specimen. He underwent 3 courses of chemotherapy with BEP regimen, and following surgical resection of the tumor, left upper lobectomy and partial resection of pericardium via median sternotomy. Pathological diagnosis of the resected tumor was mature cystic teratoma. For 9 months no recurrence of the tumor has been observed.

Combined Modality Therapy↗

PubMed1999

T-cell co-stimulation through B7RP-1 and ICOS.

T-cell activation requires co-stimulation through receptors such as CD28 and antigen-specific signalling through the T-cell antigen receptor. Here we describe a new murine costimulatory receptor-ligand pair. The receptor, which is related to CD28 and is the homologue of the human protein ICOS, is expressed on activated T cells and resting memory T cells. The ligand, which has homology to B7 molecules and is called B7-related protein-1 (B7RP-1), is expressed on B cells and macrophages. ICOS and B7RP-I do not interact with proteins in the CD28-B7 pathway, and B7RP-1 co-stimulates T cells in vitro independently of CD28. Transgenic mice expressing a B7RP-1-Fc fusion protein show lymphoid hyperplasia in the spleen, lymph nodes and Peyer's patches. Presensitized mice treated with B7RP-1-Fc during antigen challenge show enhanced hypersensitivity. Therefore, B7RP-1 exhibits co-stimulatory activities in vitro and in vivo. ICOS and B7RP-1 define a new and distinct receptor-ligand pair that is structurally related to CD28-B7 and is involved in the adaptive immune response.

Amino Acid Sequence↗

PubMed1999

Identification and characterization of a new phospholipase C-like protein, PLC-L(2).

We have isolated a cDNA encoding a novel protein, PLC-L(2), with homology to the phospholipase C-like protein PLC-L and delta-type phospholipase C. PLC-L(2) contains a relatively well-conserved PH domain, PLC catalytic region, and X and Y domains. However, it did not have PLC activity. This inactivation was thought to be caused by the replacement of two amino acids that are essential for PLC activity, His356 and Tyr552, with Thr and Phe in the X and Y domain. PLC-L(2) has a wide distribution with strong expression in skeletal muscle and mapped to chromosome 3p24-25. The PH domain of PLC-L(2) bound strongly to PI(4,5)P(2) and Ins(1,4,5)P(3), and moderately to PI(4)P and PI(3,4,5)P(3). PLC-L(2) predominantly localized to perinuclear areas in both myoblast and myotube C2C12 cells. Ectopically expressed GFP-PLC-L(2) also mainly localized in perinuclear areas, including endoplasmic reticulum in COS 7 cells. Furthermore, the expression of GFP-PH showed the same intracellular distribution as the full-length PLC-L(2). All these results suggest that PLC-L(2) plays an important role in the regulation of Ins(1,4, 5)P(3) around the endoplasmic reticulum on which the Ins(1,4,5)P(3) receptor exists.

Adaptor Proteins, Signal Transducing↗