Regulation of gap junction protein (connexin) genes and function in differentiating ES cells.
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Animals↗
Biomedical subjects
T Kaneko
Publications and source records attributed to T Kaneko.
Oropharyngeal airway appliance for infant with upper airway obstruction: report of a case.
A palatal appliance with oropharyngeal tube that reduces the upper airway obstructions of an eleven-month-old male infant with severe cerebral palsy is presented. The palatal appliance was composed of the base plate, the outer guide tube that held the oropharyngeal tube inside it, and the extra outer guide tube for the suction catheter. After the setting of the appliance, respiratory distress was improved without side effects.
Airway Obstruction↗
[Coronary artery bypass grafting in octogenarian].
Coronary artery bypass graftings (CABG) in elderly patients are increasing in recent years. Several studies have shown that the rate of complications and mortality is higher in elderly patients than in younger ones. This report presents results of CABG in octogenarians. From January 1996 to December 1999, 362 patients underwent isolated CABG, of whom 15 were over 80 years old (80-year group) and 122 were 70-79 years old (70-year group). Preoperative cardiac function was worse in the 80-year group than in 70-year group [60% vs 29% in Canadian Cardiovascular Society (CCS) class III or IV]. No significant difference was found between two groups in extracorporeal circulation time, aortic clamp time, the number of bypasses and postoperative complications. We conclude that CABG should not be excluded in octogenarians because of their chronological age alone.
Age Factors↗
Characterization of genes encoding multi-domain proteins in the genome of the filamentous nitrogen-fixing Cyanobacterium anabaena sp. strain PCC 7120.
Computational analysis of gene structures in the genome of Anabaena sp. PCC 7120 revealed the presence of a large number of genes encoding proteins with multiple functional domains. This was most evident in the genes for signal transduction pathway and the related systems. Comparison of the putative amino acid sequences of the gene products with those in the Pfam database indicated that and PAS domains which may be involved in signal recognition were extremely abundant in Anabaena: 87 GAF domains in 62 ORFs and 140 PAS domains in 59 ORFs. As for the two-component signal transduction system, 73, 53, and 77 genes for simple sensory His kinases, hybrid His kinases and simple response regulators, respectively, many of which contained additional domains of diverse functions, were presumptively assigned. A total of 52 ORFs encoding putative Hanks-type Ser/Thr protein kinases with various domains such as WD-repeat, GAF and His kinase domains, as well as genes for presumptive protein phosphatases, were also identified. In addition, genes for putative transcription factors and for proteins in the cAMP signal transduction system harbored complex gene structures with multiple domains.
Bacterial Proteins↗
Structural analysis of a Lotus japonicus genome. I. Sequence features and mapping of fifty-six TAC clones which cover the 5.4 mb regions of the genome.
A total of 56 TAC clones with an average insert size of 100 kb were isolated from a TAC library of the Lotus japonicus genome based on the expressed sequences tags (ESTs), cDNA and gene information, and their nucleotide sequences were determined according to the shot-gun based strategy. The total length of the sequenced regions is 5,473,195 bp. By comparison with the sequences in protein and EST databases and analysis with computer programs for gene modeling, a total of 605 potential protein-encoding genes with known or predicted functions, 69 gene segments, and 172 pseudogenes were identified. The average density of the genes assigned so far is 1 gene/8120 bp. Introns were identified in approximately 78% of the potential genes. There was an average of 3.8 introns per gene and the average length of the introns was 375 bp. DNA markers were generated based on the nucleotide sequences obtained, and each clone was mapped onto the linkage map using the F2 mapping population derived from a cross of L. japonicus Gifu B-129 and Miyakojima MG-20. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.
Base Sequence↗
CB1-cannabinoid and mu-opioid receptor co-localization on postsynaptic target in the rat dorsal horn.
Cannabinoids and opioids interact in the control of nociception at the spinal level. Likely, several mechanisms are involved, with one of them being co-localization of cannabinoid and opioid receptors. In order to validate this hypothesis, a double labeling study of CB1 cannabinoid receptors and mu-opioid receptors in the dorsal horn of the rat spinal cord was performed. A strong co-localization of CB1 and mu-opioid receptors was observed in lamina II interneurons at the ultrastructural level. The physiological consequences of the co-localization are discussed.
Animals↗
Immunocytochemical localization of GABA(B) receptors in mesencephalic trigeminal nucleus neurons in the rat.
We examined immunoreactivities for gamma-aminobutyric acidB-receptor (GABA(B)R) subtypes, GABA(B)R1 and GABA(B)R2, in the mesencephalic trigeminal nucleus neurons (MTN neurons) of the rat. Immunoreactivity for GABA(B)R1 was prominent in cell bodies of MTN, whereas that for GABA(B)R2 was very weak, if existed. For electron microscopy, the immunogold-silver method for GABA(B)R1 was combined with the immunoperoxidase method for glutamic acid decarboxylase (GAD: the synthetic enzyme of GABA). Immunogold-silver particles indicating GABA(B)R1 immunoreactivity were distributed widely in the cytoplasm of the cell bodies postsynaptic to GAD-immunoreactive axon terminals, but were rarely associated with synaptic membrane specialization or extrasynaptic sites of plasma membrane. It has been indicated that GABA(B)R1 may not be transported to plasma membrane when no GABA(B)R2 exists. Thus, it was presumed that GABA(B)R1 in the cell body of the rat MTN neurons might not be involved in the synaptic transmission.
Animals↗
Calpain-dependent proteolysis of merlin occurs by oxidative stress in meningiomas: a novel hypothesis of tumorigenesis.
BACKGROUND: The purpose of this study is to indicate that oxidative stress may contribute to occurrence of meningiomas. Recently, it was reported that aside from the neurofibromatosis type 2 (NF2) gene mutations, the calpain-dependent proteolysis of the NF2 gene product, merlin might be closely related to the development of certain NF2-related tumors. Although meningiomas are well known to occur more frequently in aged persons, it still remains unknown why calpain activation occurs predominantly in them. Because the production of free radicals with aging might be one of the causes of calpain activation especially in leptomeningeal cells being devoid of blood supply, the authors examined the relations between mu-calpain activation and merlin proteolysis induced by the oxidative stress. METHODS: The authors examined 12 patient-derived sporadic meningiomas and their primary cultured cells. Malignant glioma cell line (U-251MG), which had no relation to NF2, was used as a control. They were exposed to hydrogen peroxide (H2O2) for 1 hour. After oxidative stress, they were examined by Western blot and immunofluorescence microscopic analyses. RESULTS: Despite the consistent expressions of activated mu-calpain in 11 of 12 meningioma tissues, this calpain activation completely disappeared after culture; instead the full-length merlin appeared again in 8 of 11 cases. The treatment of cultured cells with hydrogen peroxide induced both mu-calpain-dependent cleavage of merlin and reduction of an intrinsic calpain inhibitor calpastatin. Such proteolysis was significantly blocked by a specific calpain inhibitor, Z-LLal. The full-length merlin was immunocytochemically colocalized with activated mu-calpain at the plasma membrane, and, after mu-calpain activation, the fragment of merlin translocated to the perinuclear cytoplasm or into the nucleus. CONCLUSIONS: These findings suggest that oxidative stress-induced activation of mu-calpain causes proteolysis of merlin conceivably to impair cell adhesion and/or contact inhibition of meningioma cells.
Brain Neoplasms↗
Accumulation of oxidative DNA damage, 8-oxo-2'-deoxyguanosine, and change of repair systems during in vitro cellular aging of cultured human skin fibroblasts.
Effects of in vitro cellular aging on the content of 8-oxo-2'-deoxyguanosine, a typical oxidation product of DNA bases, were examined in cultured human skin fibroblasts. The 8-oxo-2'-deoxyguanosine content in the DNA of TIG-3S cells established from skin tissues of a fetal donor increased immediately before the cessation of proliferation. TIG-114 and TIG-104 cells established from skin tissues of adult and aged donors, respectively, showed similar changes in 8-oxo-2'-deoxyguanosine content during in vitro cellular aging. The accumulation of 8-oxo-2'-deoxyguanosine in late-passage cells was dependent on the number of cell divisions, and not on the cultivation time. Increases in the activities of superoxide dismutase and glutathione peroxidase were observed prior to the increase in 8-oxo-2'-deoxyguanosine content, while the catalase activity decreased gradually during in vitro cellular aging at late-passage. Furthermore, the activities of 8-oxo-2'-deoxyguanosine endonuclease and DNA polymerases decreased with the progression of proliferation. These results indicate that defense systems against oxidative stress in late-passage cells remain sufficiently active before the cessation of cell division, but that repair systems against oxidative damage decay at late-passage. Oxidative stress beyond the antioxidant capacity and/or repair activity seems to result in an accumulation of 8-oxo-2'-deoxyguanosine in late-passage cells.
8-Hydroxy-2'-Deoxyguanosine↗
Complete genomic sequence of the filamentous nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120.
The nucleotide sequence of the entire genome of a filamentous cyanobacterium, Anabaena sp. strain PCC 7120, was determined. The genome of Anabaena consisted of a single chromosome (6,413,771 bp) and six plasmids, designated pCC7120alpha (408,101 bp), pCC7120beta (186,614 bp), pCC7120gamma (101,965 bp), pCC7120delta (55,414 bp), pCC7120epsilon (40,340 bp), and pCC7120zeta (5,584 bp). The chromosome bears 5368 potential protein-encoding genes, four sets of rRNA genes, 48 tRNA genes representing 42 tRNA species, and 4 genes for small structural RNAs. The predicted products of 45% of the potential protein-encoding genes showed sequence similarity to known and predicted proteins of known function, and 27% to translated products of hypothetical genes. The remaining 28% lacked significant similarity to genes for known and predicted proteins in the public DNA databases. More than 60 genes involved in various processes of heterocyst formation and nitrogen fixation were assigned to the chromosome based on their similarity to the reported genes. One hundred and ninety-five genes coding for components of two-component signal transduction systems, nearly 2.5 times as many as those in Synechocystis sp. PCC 6803, were identified on the chromosome. Only 37% of the Anabaena genes showed significant sequence similarity to those of Synechocystis, indicating a high degree of divergence of the gene information between the two cyanobacterial strains.
Anabaena↗
Size-related and size-unrelated functional heterogeneity among pancreatic islets.
Functional heterogeneity of pancreatic islets was systematically analyzed for the first time using freshly isolated single rat pancreatic islets. First, 60 islets were sequentially exposed to 3, 9.4, 15.6, and 24.1 mM glucose for 30 min each in incubation experiments: 36 (60%) responded in a concentration-dependent and 19 (32%) in an all-or-none manner, and 5 (8%) islets did not respond to high glucose. As a group, the larger the islet, the higher the beta cell glucose sensitivity. However, glucose-stimulated elevation of [Ca2+]i in the beta cell. insulin/glucagon ratio in the islet, and expression of glucose transporter 2, glucokinase, and pancreatic duodenal homeobox factor-1 in the beta cell were not significantly related to islet size. Second, 50 islets were stimulated with 16.7 mM glucose in perifusion. A biphasic insulin release was found in 39 (78%), and no or little first phase response in 11 (22%) islets, irrespective of the islet size. Nevertheless, when the response was plotted as a group, it was clearly biphasic. Islet size, insulin content and the amount of insulin release were positively correlated with each other. In conclusion, there are size-related and size-unrelated functional diversity among pancreatic islets. The reason for such heterogeneity remained to be determined.
Animals↗
Protein kinase C gamma-like immunoreactivity in the substantia gelatinosa of the medullary dorsal horn of the rat.
We examined protein kinase C gamma-immunoreactivity (PKCgamma-IR) in the substantia gelatinosa (SG) of the rat medullary dorsal horn (MDH). The density of PKCgamma-IR in the MDH was most intense in the SG. The number of neurons with PKCgamma-IR were also much larger in the SG than in the other layers of the MDH. Double-immunohistochemical studies indicated light and electron microscopically that substance P-containing fibers and I-B4 (isolectin from Bandeiraea simplicifolia)-labeled fibers made synapses on SG neurons with PKCgamma-IR, indicating that SG neurons with PKCgamma might receive nociceptive primary afferent fibers. The results support the notion that PKCgamma in the MDH may contribute to the regulation of the nociception.
Afferent Pathways↗
Protein kinase C gamma-like immunoreactivity of trigeminothalamic neurons in the medullary dorsal horn of the rat.
We examined protein kinase C gamma-like immunoreactivity (PKCgamma-LI) of trigeminothalamic neurons in the rat medullary dorsal horn (MDH) after injecting a retrograde tracer, Fluoro-Gold (FG), into the thalamus. Over 90% of FG-labeled neurons in the marginal layer (lamina I) and a few FG-labeled neurons in the superficial part of the magnocellular layer (lamina III) showed PKCgamma-LI. No PKCgamma-neurons in the substantia gelatinosa (lamina II) were labeled with FG. PKCgamma-mediated regulation of trigeminothalamic neurons may contribute to the changes in MDH activity during persistent pain.
Animals↗
Distinct constitutive and low-CO2-induced CO2 uptake systems in cyanobacteria: genes involved and their phylogenetic relationship with homologous genes in other organisms.
Cyanobacteria possess a CO(2)-concentrating mechanism that involves active CO(2) uptake and HCO(3)(-) transport. For CO(2) uptake, we have identified two systems in the cyanobacterium Synechocystis sp. strain PCC 6803, one induced at low CO(2) and one constitutive. The low CO(2)-induced system showed higher maximal activity and higher affinity for CO(2) than the constitutive system. On the basis of speculation that separate NAD(P)H dehydrogenase complexes were essential for each of these systems, we reasoned that inactivation of one system would allow selection of mutants defective in the other. Thus, mutants unable to grow at pH 7.0 in air were recovered after transformation of a DeltandhD3 mutant with a transposon-bearing library. Four of them had tags within slr1302 (designated cupB), a homologue of sll1734 (cupA), which is cotranscribed with ndhF3 and ndhD3. The DeltacupB, DeltandhD4, and DeltandhF4 mutants showed CO(2)-uptake characteristics of the low CO(2)induced system observed in wild type. In contrast, mutants DeltacupA, DeltandhD3, and DeltandhF3 showed characteristics of the constitutive CO(2)-uptake system. Double mutants impaired in one component of each of the systems were unable to take up CO(2) and required high CO(2) for growth. Phylogenetic analysis indicated that the ndhD3/ndhD4-, ndhF3/ndhF4-, and cupA/cupB-type genes are present only in cyanobacteria. Most of the cyanobacterial strains studied possess the ndhD3/ndhD4-, ndhF3/ndhF4-, and cupA/cupB-type genes in pairs. Thus, the two types of NAD(P)H dehydrogenase complexes essential for low CO(2)-induced and constitutive CO(2)-uptake systems associated with the NdhD3/NdhF3/CupA-homologues and NdhD4/NdhF4/CupB-homologues, respectively, appear to be present in these cyanobacterial strains but not in other organisms.
Biological Transport↗
Dominant localization of prostaglandin D receptors on arachnoid trabecular cells in mouse basal forebrain and their involvement in the regulation of non-rapid eye movement sleep.
Infusion of prostaglandin (PG) D(2) into the lateral ventricle of the brain induced an increase in the amount of non-rapid eye movement sleep in wild-type (WT) mice but not in mice deficient in the PGD receptor (DP). Immunofluorescence staining of WT mouse brain revealed that DP immunoreactivity was dominantly localized in the leptomeninges (LM) of the basal forebrain but that PGD synthase immunoreactivity was widely distributed in the LM of the entire brain. Electron microscopic observation indicated that DP-immunoreactive particles were predominantly located on the plasma membranes of arachnoid trabecular cells of the LM. The region with the highest DP immunoreactivity was clearly defined as bilateral wings in the LM of the basal forebrain located lateral to the optic chiasm in the proximity of the ventrolateral preoptic area, one of the putative sleep centers, and the tuberomammillary nucleus, one of the putative wake centers. The LM of this region contained DP mRNA 70-fold higher than that in the cortex as judged from the results of quantitative reverse transcription-PCR. PGD(2) infusion into the subarachnoid space of this region increased the extracellular adenosine level more than 2-fold in WT mice but not in the DP-deficient mice. These results indicate that DPs in the arachnoid trabecular cells of the basal forebrain mediate an increase in the extracellular adenosine level and sleep induction by PGD(2).
Adenosine↗
Colocalization of neuronal nitric oxide synthase and neurokinin-1 receptor in striatal interneurons in the rat.
It has been established that nitric oxide synthase (NOS)-containing aspiny neurons constitute one class of interneurons in the striatum, and that substance P (SP)-containing projection neurons give off many axon collaterals within the striatum. In the present study, we investigated a morphological substrate of possible influences of SP-containing projection neurons upon NOS-containing interneuron in the rat striatum; colocalization of immunoreactivities for NOS and NK-1 type tachykinin receptor (NK1R: SP receptor) was examined by a double-immunofluorescence histochemistry. The vast majority (94.6%) of NOS-positive neurons showed NK1R immunoreactivity, whereas only smaller cells of NK1R-positive neurons (61.2% of NK1R-positive neurons) displayed NOS immunoreactivity. The results indicated that the NOS-containing interneurons were under direct control of SP-containing projection neurons in the striatum.
Animals↗
Monitoring of methyl jasmonate-responsive genes in Arabidopsis by cDNA macroarray: self-activation of jasmonic acid biosynthesis and crosstalk with other phytohormone signaling pathways.
Jasmonates mediate various physiological events in plant cells such as defense responses, flowering, and senescence through intracellular and intercellular signaling pathways, and the expression of a large number of genes appears to be regulated by jasmonates. In order to obtain information on the regulatory network of jasmonate-responsive genes (JRGs) in Arabidopsis thaliana (Arabidopsis), we screened 2880 cDNA clones for jasmonate responsiveness by a cDNA macroarray procedure. Since many of the JRGs reported so far have been identified in leaf tissues, the cDNA clones used were chosen from a non-redundant EST library that was prepared from above-ground organs. Hybridization to the filters was achieved using alpha-33P-labeled single-strand DNAs synthesized from mRNAs obtained from methyl jasmonate (MeJA)-treated and untreated Arabidopsis seedlings. Data analysis identified 41 JRGs whose mRNA levels were changed by more than three fold in response to MeJA. This was confirmed by Northern blot analysis by using eight representatives. Among the 41 JRGs identified, 5 genes were JA biosynthesis genes and 3 genes were involved in other signaling pathways (ethylene, auxin, and salicylic acid). These results suggest the existence of a positive feedback regulatory system for JA biosynthesis and the possibility of crosstalk between JA signaling and other signaling pathways.
Acetates↗
Analytical estimate of percolation for multicomponent fluid mixtures.
The size of a dense region of a particular constituent (L(s)) in a nonuniform distribution of particles generated in a multicomponent fluid mixture can develop under certain conditions. If both the attractive force between an L(s) particle and a particle of the other constituents (L(c)(s)) and the attractive force between L(c)(s) particles are much weaker than that between L(s) particles, then the percolation due to the growth of the dense region of L(s) particles can hardly be affected by the addition of L(c)(s) particles into the fluid mixture. In that case, dense regions composed of L(c)(s) particles can be formed passively. To derive these results, it is assumed that such a dense region is an ensemble of particles bound to each other as particle pairs that satisfy the condition E(ij)+u(ij)(r)</=0, where E(ij) is the relative kinetic energy for i and j particles and u(ij)(r) is the pair potential. The percolation in the fluid mixture can be estimated analytically. According to the pair connectedness function P(ij)(r) derived for evaluating the percolation, the probability that an L(s) particle is located near another L(s) particle can be insensitive to the addition of L(c)(s) particles. The magnitude of P(ij)(r) can be maximized for a pair of i-j particles interacting with the most strongly attractive force having the largest value of the effective ranges in a fluid mixture system. These particles can contribute to making the phase behavior of the fluid mixture complicated.
Journal Article↗