Accidental subdural catheterization suspected on administration of a test dose of lidocaine and successfully managed by a small dose of dibucaine.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
T Satoh
Publications and source records attributed to T Satoh.
Association of the proto-oncogene product dbl with G protein betagamma subunits.
The Rho family of GTP-binding proteins has been implicated in the regulation of various cellular functions including actin cytoskeleton-dependent morphological change. Its activity is directed by intracellular signals mediated by various types of receptors such as G protein-coupled receptors. However, the mechanisms underlying receptor-dependent regulation of Rho family members remain incompletely understood. The guanine nucleotide exchange factor (GEF) Dbl targets Rho family proteins thereby stimulating their GDP/GTP exchange, and thus is believed to be involved in receptor-mediated regulation of the proteins. Here, we show the association of Dbl with G protein betagamma subunits (Gbetagamma) in transient co-expression and cell-free systems. An amino-terminal portion conserved among a subset of Dbl family proteins is sufficient for the binding of Gbetagamma. In fact, Ost and Kalirin, which contain this Gbetagamma-binding motif, also associate with Gbetagamma. c-Jun N-terminal kinase was synergistically activated upon co-expression of Dbl and Gbeta in a dominant-negative Rho-sensitive manner. However, GEF activity of Dbl toward Rho as measured by in vitro GDP binding assays remained unaffected following Gbetagamma binding, suggesting that additional signals may be required for the regulation of Dbl.
Animals↗
Site-directed mutagenesis of the response regulator DmsR for the dmsCBA operon expression in Rhodobacter sphaeroides f. sp. Denitrificans: An essential residue of proline-130 in the linker.
DmsR protein is a member of the OmpR response regulator subfamily that activates the transcription of the dmsCBA operon in Rhodobacter sphaeroides f. sp. denitrificans. By site-directed mutagenesis some functional amino acid residues were investigated in DmsR, which consists of the N-terminal regulatory and the C-terminal DNA-binding domains and the linker connecting the two domains. The substitution of P130S in the linker caused decreases of both DNA-binding and transcriptional activator activities. Introducing additional substitutions of R129P or D131P to the DmsR-P130S derivative recovered both activities, demonstrating necessity of proline residue at one of the positions 129-131 in the linker. Substitutions of D12A, D55A, and K104M, at residues conserved in the phosphorylation region, caused no production of DMSO reductase, but retained DNA-binding ability, suggesting that unphosphorylated DmsR also has high affinity to its target nucleotide sequence of DNA. Substitutions in the C-terminal domain suggested the presence of a winged helix-turn-helix structure observed in the DNA-binding domain of the Escherichia coli OmpR.
Bacterial Proteins↗
Re: Modification of clinical presentation of prostate tumors by a novel genetic variant in CYP3A4.
Explore the source record for details and available documents.
Asian People↗
DNA binding and interaction with the nuclear receptor corepressor of thyroid hormone receptor are required for ligand-independent stimulation of the mouse preprothyrotropin-releasing hormone gene.
A negative thyroid hormone response element (TRE) in the mouse preprothyrotropin-releasing hormone (TRH) gene was previously mapped within the proximal promoter element between -83 and +53 that contained a TRE half-site motif at -57 (-57TGACCT-51). In transfection experiments, the promoter activity is stimulated by unliganded thyroid hormone receptor (TR) and T3 reverses the basal promoter stimulation. In this study, we determined whether the direct binding of TR to the TRE half-site in the mouse TRH gene is required for the ligand-independent stimulation using a transient transfection assay into CV-1 cells and electrophoretic mobility shift assays (EMSA). In addition, the role of a corepressor protein for the ligand-independent stimulation was examined using a putative splicing variant of the nuclear receptor corepressor (N-CoRI). Point mutations introduced into the TRE half-site at -57 eliminated the binding of TR and the stimulatory effect of unliganded TR. Two mutant TRs lacking DNA-binding activity and two CoR box mutant TRs showed no stimulation in the wild-type TRH promoter. The cotransfected N-CoRI potentiated the ligand-independent stimulation by the wild-type TR, but did not compensate for the impaired function of the CoR box mutant TR. In EMSA, TR strongly bound as homodimers and weakly as heterodimers with retinoid X receptor (RXR) to the element containing the TRE half-site at -57. Binding of TR to the TRE half-site was essential to form homo- and heterodimers, and the RXR binding site appeared to be located downstream of the TRE half-site. In vitro translated N-CoRI preferentially bound TR homodimers over TR/RXR heterodimers. These results collectively suggest that the DNA-bound TR/corepressor complex might be directly involved in the ligand-independent stimulation of the mouse TRH gene promoter.
Animals↗
Renal neoplasias in patients receiving dialysis and renal transplantation: clinico-pathological features and p53 gene mutations.
BACKGROUND: In Japan, the relative risk for renal cell carcinoma (RCC) in renal transplants was about 80-fold higher than that in the general population. Depressed immune surveillance due to the use of immunosuppressive agents was considered to cause cancer. Before renal transplantation, a vast majority of patients received hemodialysis, a known causative factor for acquired cystic disease of kidney (ACDK). Because ACDK is also considered to predispose to RCC, at least two risk factors for cancer accumulate in renal transplants. METHODS: In our study, clinicopathological features together with p53 gene mutations were analyzed in 218 patients with RCC: 22 received dialysis followed by renal transplantation, 39 received dialysis alone, and 157 sporadic RCC. P53 mutations were analyzed on DNA extracted from paraffin-embedded specimens with use of single strand conformation polymorphism, followed by direct sequencing. RESULTS: RCC in transplants shared several clinicopathological features with those in dialysis patients, which included small size and multiplicity of tumor, relatively high frequency of presence of ACDK, and papillary type of RCC. p53 gene mutations were infrequent in RCC of any clinical setting. CONCLUSIONS: Atrophic kidney at the end-stage of renal failure and under dialysis have lesions of ACDK that might predispose to RCC in dialysis and transplant patients.
Adult↗
Lipid-binding and antimicrobial properties of synthetic peptides of bovine apolipoprotein A-II.
We previously showed that bovine apolipoprotein A-II (apoA-II) had antimicrobial activity against Escherichia coli and the yeast Saccharomyces cerevisiae in PBS. We have characterized here the active domain of apoA-II using synthetic peptides. A peptide corresponding to C-terminal residues Leu(49)-Thr(76) exhibited significant antimicrobial activity against E. coli in PBS, but not against S. cerevisiae. Experiments using amino-acid-substituted peptides indicated that the residues Phe(52)-Phe(53)-Lys(54)-Lys(55) are required for the activity. Peptide Leu(49)-Thr(76) induced the release of calcein trapped inside the vesicles whose lipid composition resembles that of E. coli membrane, suggesting that peptide Leu(49)-Thr(76) can destabilize the E. coli membrane. CD measurements showed that the alpha-helicity of peptide Leu(49)-Thr(76) increased from 3.5 to 36% by addition of the vesicles. When E. coli cells were incubated with peptide Leu(49)-Thr(76), some proteins were released to the external medium, probably owing to membrane destabilization caused by the peptide. In electron micrographs of E. coli cells treated with peptide Leu(49)-Thr(76), transparent nucleoids and granulated cytoplasm were observed. Amino acid substitutions, Phe(52)Phe(53)-->AlaAla (Phe(52, 53)-->Ala) in peptide Leu(49)-Thr(76) caused the loss of antimicrobial activity against E. coli, although protein-releasing activity was retained. Electron micrographs of the cells treated with peptide Leu(49)-Thr(76)(Phe(52,53)-->Ala) revealed morphological change only at the nucleoids. Therefore peptide Leu(49)-Thr(76) appears to primarily target the cytoplasm rather than the membrane of E. coli cells.
Amino Acid Sequence↗
The endothelial cell protein C receptor (EPCR) functions as a primary receptor for protein C activation on endothelial cells in arteries, veins, and capillaries.
Plasma protein C functions as an anticoagulant when it is converted to the active form of serine protease. Protein C activation has been found to be mediated by the endothelial cell surface thrombin/thrombomodulin (TM) complex. In addition, we recently identified the endothelial cell protein C/activated protein C receptor (EPCR) which is capable of high-affinity binding for protein C. In this study, we established monoclonal antibodies (mAbs) against EPCR including several function blocking antibodies. Immunohistochemical analysis using these mAbs demonstrated that EPCR is widely expressed in the endothelial cells of arteries, veins, and capillaries in the lung, heart, and skin. Function blocking anti-EPCR mAbs strongly inhibited protein C activation mediated by primary cultured arterial endothelial cells which express abundant EPCR. Anti-EPCR mAbs also prevent protein C activation mediated by microvascular endothelial cells. These results indicate that EPCR functions as an important regulator for the protein C pathway in various types of vessels.
Antibodies, Monoclonal↗
Toxicological significance in the cleavage of esterase-beta-glucuronidase complex in liver microsomes by organophosphorus compounds.
Egasyn is an accessory protein of beta-glucuronidase (beta-G) in the liver microsomes. Liver microsomal beta-G is stabilized within the luminal site of the microsomal vesicles by complexation with egasyn which is one of the carboxylesterase isozymes. We investigated the effects of organophosphorus compounds (OPs) such as insecticides on the dissociation of egasyn-beta-glucuronidase (EG) complex. The EG complex was easily dissociated by administration of OPs, i.e. fenitrothion, EPN, phenthionate, and bis-beta-nitrophenyl phosphate (BNPP), and resulting beta-G dissociated was released into blood, leading to the rapid and transient increase of plasma beta-G level with a concomitant decrease of liver microsomal beta-G level. In a case of phenthionate treatment, less increase in plasma beta-G level was observed, as compared with those of other OPs. This may be explained by the fact that phenthionate was easily hydrolyzed by carboxylesterase. Similarly, carbamate insecticides such as carbaryl caused rapid increase of plasma beta-G level. In contrast, no significant increase of plasma beta-G level was observed when pyrethroid insecticides were administered to rats. This is due to the fact that pyrethroids such as phenthrin and allethrin were easily hydrolyzed by A-esterase as well as carboxylesterase. On the other hand, addition of OPs to the incubation mixture containing liver microsomes caused the release of beta-G from microsomes to the medium. From these in vivo and in vitro data, it is concluded that increase of the plasma beta-G level after OP administration is much more sensitive biomarker than cholinesterase inhibition to acute intoxication of OPs and carbamates.
Animals↗
Prostaglandin J2 and its metabolites promote neurite outgrowth induced by nerve growth factor in PC12 cells.
Although A- and J-type prostaglandins (PG's) arrest the cell cycle at the G1 phase in vitro and suppress tumor growth in vivo, their effects on neuronal cells have not so far been clarified. Here, we found promotion of neurite outgrowth as a novel biological function of PGJ's. In PC12h cells, PGJ's (PGJ2, Delta12-PGJ2 and 15-deoxy-Delta12,14-PGJ2) promoted neurite outgrowth in the presence of nerve growth factor (NGF), whereas they themselves did not show such a promotion. The potency of promoting neurite outgrowth was PGJ2 < Delta12-PGJ2 < 15-deoxy-Delta12,14-PGJ2. However, troglitazone, an activator of peroxisome proliferator-activated receptorgamma (PPARgamma), and other PG's including PGA1, PGA2 and PGD2 did not promote neurite outgrowth. These results suggest that PGJ's promote neurite outgrowth independently of PPARgamma activation.
Animals↗
G protein beta gamma subunit-dependent Rac-guanine nucleotide exchange activity of Ras-GRF1/CDC25(Mm).
Ras-GRF1 has been implicated as a Ras-specific guanine nucleotide exchange factor (GEF), which mediates calcium- and muscarinic receptor-triggered signals in the brain. Although a Dbl homology domain known as a motif conserved among GEFs that target Rho family GTP-binding proteins exists in Ras-GRF1, GEF activity toward Rho family proteins has not been observed. Here we show that Ras-GRF1 exhibits Rac1-specific GEF activity when recovered from cells overexpressing G protein beta gamma subunits (Gbeta gamma). Substitution of conserved amino acids within the Dbl homology domain abolished this activity. Activation of the Rac pathway in the cell was further evidenced by synergistic activation of the stress kinase JNK1 by Ras-GRF1 and Gbeta gamma, which is sensitive to inhibitory action of dominant-negative Rac1(17N). In addition, association of Ras-GRF1 with Rac1(17N) was demonstrated by coimmunoprecipitation. Evidence for the involvement of tyrosine kinase(s) in Gbeta gamma-mediated induction of Rac1-specific GEF activity was provided by the use of specific inhibitors. These results suggest a role of Ras-GRF1 for regulating Rac-dependent as well as Ras-dependent signaling pathways, particularly in the brain functions.
Animals↗
Generation of reactive oxygen species, release of L-glutamate and activation of caspases are required for oxygen-induced apoptosis of embryonic hippocampal neurons in culture.
Oxygen-induced cell death in embryonic neurons is a useful in vitro model of neuronal apoptosis to study the molecular mechanisms underlying the cell death induced by oxidative stress. In the present study, we examined the involvement of reactive oxygen species and glutamate in the high (50%) oxygen-induced death of cultured hippocampal neurons. During the course of cell death, increases in O2- and hydrogen peroxide (H2O2) levels were observed. On the other hand, superoxide dismutase (SOD), catalase and deferoxamine (DFX), which have inhibitory effects on the generation of O2-, H2O2 and hydroxyl radicals, respectively, protected the neurons. These results suggested that both O2- and H2O2 play important roles in this apoptosis. Antagonists of NMDA and AMPA/kinate (AMPA/KA) receptors and an inhibitor of glutamate release partially prevented the apoptosis, suggesting that exposure to high oxygen enhances glutamate release, which results in activation of NMDA receptor and AMPA/KA receptor. In addition, specific nitric oxide (NO) scavenger and NO synthetase inhibitors blocked the apoptosis, indicating that NO and/or peroxynitrite are involved in this mechanism of cell death. Caspase inhibitors also blocked the neuronal apoptosis. These results suggested that multiple effectors including generation of reactive oxygen species, release of L-glutamate and activation of caspases are activated during the death induced by high oxygen.
Animals↗
Application of laser scanning cytometry to the analysis of chromosomal aberrations induced by benzo[a]pyrene in CHO-WBLT cells.
BACKGROUND: A recently developed laser scanning cytometry technique was applied to cytometric studies to detect rapidly stable chromosomal aberrations induced by a carcinogen in a Chinese hamster fibroblast cell line, CHO-WBLT. METHODS: Individual chromosomes were collected from metaphase cells by a syringe technique and spread on slides. The DNA content of each chromosome stained with propidium iodide was measured with a laser scanning cytometer (LSC). A characteristic DNA histogram, designated as the "laser scanning karyotype (LSK)," was obtained from about 20,000 chromosomes of CHO-WBLT cells. Each chromosome was confirmed morphologically under the microscope by using a "re-location" system built into the LSC. RESULTS: A total of 21 chromosomes, including marker chromosomes specific to the cell line, were assigned to 10 major peaks in the LSK, which was analogous to the karyotype demonstrated with the classical Q-banding technique. In contrast, clonal sublines isolated after exposure to the carcinogen benzo[a]pyrene showed LSKs different from those found in untreated control cells, and seven of 20 clones were found to be abnormal, with a small number of chromosomal translocations and/or deletions, which were confirmed by Q-banding. CONCLUSIONS: The laser scanning cytometry technique was employed to detect stable chromosomal aberrations in CHO-WBLT cells after treatment with benzo[a]pyrene. The results obtained with this technique were comparable to those obtained by Q-banding; therefore, this method may be useful for rapid primary screening to detect stable, abnormal karyotypes induced by environmental chemicals and/or radiation.
Animals↗
Myrothecium verrucaria bilirubin oxidase and its mutants for potential copper ligands.
Bilirubin oxidase (EC:1.3.3.5) purified from a culture medium of Myrothecium verrucaria MT-1 (authentic enzyme) catalyzes the oxidation of bilirubin to biliverdin in vitro and recombinant enzyme (wild type) was obtained by using an overexpression system of the bilirubin oxidase gene with Aspergillus oryzae harboring an expression vector. The absorption and ESR spectra showed that both bilirubin oxidases are multicopper oxidases containing type 1, type 2, and type 3 coppers similar to laccase, ascorbate oxidase, and ceruloplasmin. Site-directed mutagenesis has been performed for the possible ligands of each type of copper. In some mutants, Cys457 --> Val, Ala, His94 --> Val, and His134.136 --> Val, type 1 and type 2 copper centers were perturbed completely and the enzyme activity was completely lost. Differing from the holoenzyme, these mutants showed type 3 copper signals. However, the optical and magnetic properties characteristic of type 1 copper were retained even by mutating one of the type 1 copper ligands, i.e., a mutant, Met467 --> Gly, showed a weak but apparent enzyme activity. A double mutant His456.458 --> Val had only type 1 Cu, showing a blue band at 600 nm (epsilon = 1.6 x 10(3)) and an ESR signal with very narrow hyperfine splitting (A parallel = 7.2 x 10(-)3 cm-1). Since the type 2 and type 3 coppers are not present, the mutant did not show enzyme activity. These results strongly imply that the peculiar sequence in bilirubin oxidase, His456-Cys457-His458, forms an intramolecular electron-transfer pathway between the type 1 copper site and the trinuclear center composed of the type 2 and type 3 copper sites.
Amino Acid Sequence↗
Effects of opioids on neuronal survival in culture of embryonic chick dorsal root ganglion neurons.
We studied the effects of endogenous and synthetic opioids on survival of primary-cultured dorsal root ganglion neurons of 8-day chick embryos. In the basal growth medium containing nerve growth factor (NGF), [Leu5]enkephalin, [Met5]enkephalin or selective mu-agonist, [D-Ala2, N-Me-Phe4, Gly5-ol]enkephalin (DAMGO) produced significant increase of neuronal survival in a naloxone-reversible manner. On the other hand, dynorphin A (1-13), [D-Pen2, L-Pen5] enkephalin (DPLPE) (a delta-agonist) and U-50,488 (a kappa-agonist) showed no such effect. No viable neurons were observed in the absence of NGF in spite of the presence of any opioid peptides. These results suggest that [Leu5]enkephalin and [Met5]enkephalin might increase neuronal survival by stimulating mu-opioid receptors, and that these opioid peptides are working with other growth factors but, in and by themselves, do not promote survival.
Animals↗
Three kinds of guanylate cyclase expressed in medaka photoreceptor cells in both retina and pineal organ.
Three kinds of cDNAs encoding the putative photoreceptor-specific guanylate cyclases (GCs), OlGC-R1, OlGC-R2, and OlGC-C, were isolated from a retinal cDNA library of the medaka, Oryzias latipes. The deduced amino acid sequences of OlGC-R1 and -C are closely related but slightly different from those of OlGC4 and OlGC5, respectively. In situ hybridization locates the mRNA of both OlGC-R1 and -R2 in rods, and OlGC-C mRNA is found in all four types of cone cells. It is likely that medaka rods and cones produce distinct GC subtypes and that two kinds of photoreceptor-specific GCs are coexpressed in rods. Also, hybridization signals are detected in the pineal organ, suggesting that OlGC-R1 and -C contribute also to phototransduction in pinealocytes.
Amino Acid Sequence↗
The surgical management of sacrococcygeal chordoma.
BACKGROUND: Complete excision of sacrococcygeal chordoma is necessary at initial surgery due to its poor sensitivity to radiotherapy and chemotherapy. However, due to the anatomic characteristics of this tumor, intralesional excision tends to be employed, resulting in local recurrences in many patients. METHODS: The clinical features and results of surgical treatment of 13 patients with sacrococcygeal chordoma who were treated at the Chiba Cancer Center and Chiba University beginning in 1972 were analyzed. RESULTS: Intralesional excision was performed in eight patients, marginal excision in two patients, and wide excision in three patients. Local recurrence was observed in six patients, with a high proportion occurring in the gluteal muscles attached to the sacrum (the gluteus maximus muscle and piriform muscle). Seven patients died of their disease and six patients were alive with no evidence of disease. The 5-year survival rate was 81.8% and the 10-year survival rate was 29.1%. CONCLUSIONS: It is highly possible that residual chordoma infiltrating the gluteal muscles accounts mainly for the local recurrences. Therefore, a precise preoperative assessment of the tumor infiltration into the gluteal muscles by magnetic resonance imaging is important for the prevention of local recurrence. For complete tumor removal, a radical wide posterior surgical margin of the gluteal muscles should be employed. A less radical anterior surgical margin is sufficient because there is a firm presacral fascia anterior to the sacrum. The appropriate surgical margin for the complete removal of the chordoma differs according to the location of the tumor and tissues involved.
Adult↗
Excessive release of [3H]noradrenaline and glutamate in response to simulation of ischemic conditions in rat spinal cord slice preparation: effect of NMDA and AMPA receptor antagonists.
In the present study we investigated the effects of NMDA and non-NMDA glutamate receptor antagonists on the ischemia-evoked release of [3H]noradrenaline from rat spinal cord slices. An in vitro ischemia model (oxygen and glucose deprivation) was used to simulate the ischemic conditions known to cause neuronal injury. Spinal cord slices were loaded with [3H]noradrenaline and superfused with Krebs solution in a micro-organ bath. Both axonal stimulation and ischemia increased the release of [3H]noradrenaline, but the release in response to glucose and oxygen deprivation was [Ca2+]o independent. Dizocilpine (MK-801), an NMDA receptor antagonist, suppressed the release of [3H]noradrenaline produced by ischemia, while it enhanced the release of [3H]noradrenaline evoked by electrical field stimulation. In contrast, LY300168 (GYKI-53655) [(+/-)-3-N-methylcarbamyde-1-(4-aminophenyl)-4-methyl-1.8-methylen e-dioxy-5H-2.3-benzodiazepine] and its (-)isomer LY303070 (GYKI-53784) [(-)-3-N-methylcarbamyde-1-(4-aminophenyl)-4-methyl-1.8-methylene- dioxy-5H-2.3-benzodiazepine] AMPA receptor antagonists, had no effect on the release of [3H]noradrenaline evoked by either electrical stimulation or ischemia. Desipramine, a noradrenaline uptake inhibitor, potentiated the release of [3H]noradrenaline evoked by ischemia, while in the absence of [Ca2+]o but under conditions when [3H]noradrenaline release was further increased, it reduced the release. Dizocilpine also decreased glutamate and aspartate release, measured by high performance liquid chromatography, during ischemia. It is concluded that glutamate release and NMDA receptors, but not AMPA receptors, are involved in the acute effect of oxygen and glucose deprivation on the excessive release of noradrenaline and that this release is not related to physiological axonal conduction.
Animals↗