[Neuronal plasticity and protein phosphatase].
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Animals↗
Biomedical subjects
K Fukunaga
Publications and source records attributed to K Fukunaga.
Epidermal growth factor stimulates the tyrosine phosphorylation of SHPS-1 and association of SHPS-1 with SHP-2, a SH2 domain-containing protein tyrosine phosphatase.
SHPS-1 is a 120 kDa glycosylated receptor-like protein that contains immunoglobulin-like domains in its extracellular region and four potential tyrosine phosphorylation for SH2 domain binding sites in its cytoplasmic region. Epidermal growth factor (EGF) stimulated the rapid tyrosine phosphorylation of SHPS-1 and subsequent association of SHPS-1 with SHP-2, a protein tyrosine phosphatase containing SH2 domains, in Chinese hamster ovary cells overexpressing human EGF receptors. In the cells overexpressing SHPS-1, the tyrosine phosphorylation of SHPS-1 was more evident than that observed in parent cells. However, overexpression of SHPS-1 alone did not affect the activation of MAP kinase in response to EGF. These results suggest that SHPS-1 may be involved in the recruitment of SHP-2 from the cytosol to the plasma membrane in response to EGF.
Animals↗
DY-9760e, a novel calmodulin antagonist with cytoprotective action.
We report the pharmacological characterization and cytoprotective effect of DY-9760e, 3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-( 4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate, a novel antagonist of calmodulin. DY-9760e inhibited calmodulin-dependent enzymes, including calmodulin-dependent protein kinase II and IV, calcineurin, [corrected] calmodulin-dependent phosphodiesterase and myosin light chain kinase with Ki values of 1.4, 12, 2.0, 3.8 and 133 microM, respectively. These antagonistic effects of DY-9760e were more potent than those of W-7, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, another calmodulin antagonist. This compound showed little or no effect on calmodulin-independent enzymes, such as protein kinase A and C and calpain I and II. Analysis of the hydrophobic interaction of DY-9760e with calmodulin by using 2-p-toluidinylnaphthalene-6-sulfonate and 9-anthroylcholine revealed that, like W-7, DY-9760e bound to the hydrophobic regions of calmodulin. The [14C]DY-9760e binding assay indicated that DY-9760e bound to calmodulin at one class of binding site. Finally, DY-9760e substantially protected N1E-115 neuroblastoma cells from cytotoxicity induced by the Ca2+ ionophore, A23187. These results indicate that DY-9760e, a novel calmodulin antagonist, possesses a cytoprotective action and suggest that calmodulin plays a critical role in mediating some of the biochemical events leading to cell death following Ca2+ overload.
Calcimycin↗
Application of a beta-cyclodextrin sulfate-immobilized precolumn to selective on-line enrichment and separation of heparin-binding proteins by column-switching high-performance liquid chromatography.
A column-switching high-performance liquid chromatography (HPLC) system which consisted of a beta-cyclodextrin (beta-CD) sulfate-immobilized hydrophilic vinyl-polymer gel precolumn and a reversed-phase analytical column was developed for the selective on-line enrichment and separation of heparin-binding proteins. Of 15 proteins investigated, 10 proteins having heparin-binding activity were retained on the beta-CD sulfate precolumn almost quantitatively, in contrast 5 proteins having no heparin-binding activity were not retained. Calibration graphs for basic fibroblast growth factor constructed at various sample volumes were nearly identical, indicating that the protein could be enriched by this system. The system was successfully used for the selective separation of lysozyme in egg white. The beta-CD sulfate-immobilized precolumn showed no loss of analytical performance over 2 years during which about 400 samples were analysed.
Chromatography, High Pressure Liquid↗
Hepatic allograft procurement from non-heart-beating donors: limits of warm ischemia in porcine liver transplantation.
To investigate the tolerance to warm ischemia of liver grafts from non-heart-beating donors, porcine orthotopic liver transplantation was performed using grafts obtained at various periods after cardiac arrest. Graft viability was investigated in relation to changes in hepatic adenine nucleotide metabolism. In donors, livers were divided into four groups according to warm ischemic time after cardiac arrest (group 1: 0 min, n=3; group 2: 30 min, n=3; group 3: 60 min, n=5; group 4: 90 min, n=4). Thereafter, the livers were flushed and preserved for 4 hr using 4 degrees C Euro-Collins solution. After surgery, all of the recipients in groups 1, 2, and 3 survived more than 4 days, except for one pig in group 3 that died of bleeding from an arterial catheter on day 2. By contrast, all of the recipients in group 4 died within 12 hr. The serum glutamic oxaloacetic transaminase concentration at 4 hr after reperfusion of the graft was significantly higher in group 4 (mean+/-SE, 2563+/-556 IU/L) than in groups 1, 2, and 3 (298+/-29 IU/L, 1226+/-222 IU/L, and 1181+/-174 IU/L, respectively). The adenylate energy charge of the liver graft recovered at 1 hr after reperfusion of the graft to 0.852+/-0.013, 0.845+/-0.003, and 0.842+/-0.003 in groups 1, 2, and 3, respectively. The recovery was significantly suppressed in group 4 (0.796+/-0.011). The hepatic adenosine triphosphate concentration also was significantly lower in group 4 compared with the other groups. The present study suggests that liver allografts can be used from non-heart-beating donors subjected to warm ischemia for less than 60 min. Postoperative survival is associated with prompt recovery of the adenylate energy charge of the liver graft.
Adenine Nucleotides↗
Transforming growth factor-alpha (TGF alpha)-producing gastric carcinoma with acanthosis nigricans: an endocrine effect of TGF alpha in the pathogenesis of cutaneous paraneoplastic syndrome and epithelial hyperplasia of the esophagus.
A case of well-differentiated adenocarcinoma (Borrmann type 3) of the stomach in a 76-year-old man associated with the typical skin manifestations of acanthosis nigricans and with multiple protruding lesions showing epithelial hyperplasia of the esophagus is reported. The advanced tumor was located in the cardiac region of the stomach, and measured approximately 8 cm in diameter, with partial invasion to the esophagus. The associated cutaneous lesions were characterized by hyperpigmentation and by protruding verrucous papules on the torso, head, face, neck, upper extremities, perineum, and inguinal region. Histologically, the protruding skin lesions showed keratinocytes proliferation throughout the epidermis, resulting in diffuse hyperkeratosis, papillomatosis, and acanthosis of the skin. Immunohistological analysis showed coexpression of transforming growth factor alpha (TGF-alpha) and epidermal growth factor (EGF) receptors in the tumor from the stomach. It is reasonable to conclude from this evidence that gastric carcinoma cells secrete TGF alpha in an autocrine for auto-stimulation. EGF receptor expression was also noted on the papillomatous hyperplasia of the cutaneous lesion. Serum level of TGF alpha, determined by an enzyme-linked immunosorbent assay, was high (144 pg/ml; normal, 22.0 +/- 16 pg/ml (Mean +/- SD)). Serum TGF alpha abruptly decreased to 49 pg/ml on day 7 after the total gastrectomy, and then gradually increased to 77 pg/ml within 28 days. Amelioration of the cutaneous lesions and the protruding lesions in the esophagus was observed after surgical resection of the gastric carcinoma. This suggests that the TGF alpha stimulates the proliferation of keratinocytes involved with EGF receptor. Large amounts of circulating TGF alpha in the blood over a long period released by the primary tumor seem to act as an endocrine-like mechanism causing epidermal and esophageal epithelial cells to proliferate. There is a possible link in the pathogenesis of the acanthosis nigricans as a cutaneous paraneoplastic syndrome, and epithelial hyperplasia of the esophagus.
Acanthosis Nigricans↗
Calcineurin in the adult rat hippocampus: different distribution in CA1 and CA3 subfields.
We examined the immunohistochemical regional distribution of calcineurin (Ca2+/calmodulin-dependent protein phosphatase) in the adult rat hippocampus, following various regional destruction. In the normal adult rat hippocampus, the calcineurin immunoreactivity showed a characteristic pattern. This protein phosphatase was detected in all layers of the CA1 subfield, including the cytoplasm of the pyramidal cells, whereas it was strongly evident in the stratum lucidum and moderately so in the cytoplasm of pyramidal cells in the CA3 subfield. Seven days after transient forebrain ischemia, which induced destruction of CA1 pyramidal cells, the calcineurin immunoreactivity decreased in all layers of the CA1 subfield, while the immunoreactivity for synapsin I, a marker of the presynaptic site, was preserved. Seven days after the intraventricular injection of kainate, which induced destruction of CA3 pyramidal cells, the calcineurin immunoreactivity in the stratum lucidum was preserved, although the immunostaining pattern of the stratum lucidum changed when CA3 pyramidal cells were destroyed. Seven days after mechanical destruction of the dentate gyrus and CA4 subfield, which induced destruction of mossy fibers, the calcineurin immunoreactivity in the stratum lucidum was lost, except in the far site of the stratum lucidum. In the CA1 subfield, calcineurin was mainly located in postsynaptic sites, while it was mainly located in the presynaptic sites in the mossy fibers of the CA3 subfield. The immunohistochemistry of adjacent sections with antibodies of microtubule-associated protein 2 and synapsin I, which are markers of postsynaptic and presynaptic sites respectively, supports these results. Thus, calcineurin has a different synaptical distribution in the rat hippocampus.
Animals↗
[Effect of glucose-insulin infusion on thallium-201 chloride tumor imaging].
Thallium-201 chloride (201Tl) kinetics, may be affected by serum insulin levels like potassium kinetics. The purpose of the present study was to use glucose and insulin to improve 201Tl accumulation in the tumor. The results showed that the tumor-to-normal tissue ratio after simultaneous injection of 201Tl, glucose and insulin was significantly higher than that after the injection of only 201Tl, and that a ring appearance seemed to occur after glucose and insulin injection. This preliminary study suggests that 201Tl accumulation in the tumor is enhanced by glucose and insulin administration.
Animals↗
Technetium-99m-MIBI and thallium-201 scintigraphy of primary lung cancer.
UNLABELLED: We evaluated the usefulness of 99mTc-MIBI scintigraphy in primary lung cancer in comparison with 201Tl-chloride scintigraphy. METHODS: There were 45 patients with primary lung cancer. All patients underwent dual-isotope imaging with 201Tl-chloride and 99mTc-MIBI. Regions of interest were placed over the tumors (T) and contralateral normal lung tissue (N) on one coronal view in the SPECT, and T/N ratio and retention index were calculated. RESULTS: The positive rate was 98% in both the early and delayed images for 201Tl-chloride and 96% in the early and 89% in the delayed image for 99mTc-MIBI. Both early and delayed T/N ratios for 201Tl-chloride were higher than those for 99mTc-MIBI. There was no significant correlation between T/N ratio and histological type of tumor in both images. However, in both images, there was a tendency for the early and delayed ratios to increase as the tumor diameter became larger. The retention index of 201Tl-chloride was higher than that of 99mTc-MIBI. There were no significant differences in the retention index with respect to the histological type and tumor size. CONCLUSION: The results of this preliminary clinical study suggest that 99mTl-MIBI can depict primary lung cancer similar to 201Tl-chloride. However, T/N ratio and retention index of 99mTc-MIBI in the tumor areas are significantly lower compared with those of 201Tl-chloride.
Adult↗
[A case of interstitial pneumonia induced by intravesical administration of bacillus Calmette-Guerin (BCG)].
A 61-year-old man with superficial bladder cancer, which was detected after he complained of hematuria, was treated three times with intravesical BCG administration. Since liver dysfunction was detected thereafter, he was admitted to our hospital. Three days after admission, he complained of dyspnea on exertion associated with severe hypoxemia, as well as abnormal findings on chest X-ray, i.e. extensive bilateral lung densities. We performed bronchoscopic examination and obtained bronchoalveolar lavage fluid (BALF) and lung biopsy specimens (TBLB). In the BALF, a marked increase in the total cell number, particularly lymphocytes with a high CD4/CD8 ratio was noted. TBLB specimens revealed the lesions to be numerous non-caseating granulomas. We failed to obtain definite evidence of BCG in the sputum, urine, blood, and BALF. Instead, we found that a lymphocyte stimulation test for BCG (DLST) was strongly positive. Based on these findings, severe interstitial pneumonia probably induced by hypersensitivity against BCG, was diagnosed. Anti-tuberculous agents, and steroid-pulse therapy followed by oral administration of relatively low dose of steroid ameliorated the abnormal conditions, including chest X-ray film findings and hypoxemia. The population of lymphocytes and CD4/CD8 ratio in the BALF were reduced as well. Serious interstitial pneumonia was induced by the intravesical administration of BCG, which resulted in transitional changes in the BALF cell component.
Administration, Intravesical↗
Ca(2+)-induced rebound potentiation of gamma-aminobutyric acid-mediated currents requires activation of Ca2+/calmodulin-dependent kinase II.
In cerebellar Purkinje neurons, gamma-aminobutyric acid (GABA)-mediated inhibitory synaptic transmission undergoes a long-lasting "rebound potentiation" after the activation of excitatory climbing fiber inputs. Rebound potentiation is triggered by the climbing-fiber-induced transient elevation of intracellular Ca2+ concentration and is expressed as a long-lasting increase of postsynaptic GABAA receptor sensitivity. Herein we show that inhibitors of the Ca2+/calmodulin-dependent protein kinase II (CaM-KII) signal transduction pathway effectively block the induction of rebound potentiation. These inhibitors have no effect on the once established rebound potentiation, on voltage-gated Ca2+ channel currents, or on the basal inhibitory transmission itself. Furthermore, a protein phosphatase inhibitor and the intracellularly applied CaM-KII markedly enhanced GABA-mediated currents in Purkinje neurons. Our results demonstrate that CaM-KII activation and the following phosphorylation are key steps for rebound potentiation.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
Synthesis of glycolipids containing disaccharides and two longer alkyl chains and their applications as enzyme modifiers.
The aminolysis between p-(aminomethyl)benzoic acid and lactobiono-1,5-lactone was carried out in Me2SO in quantitative yield. The amide formed thus was used directly for the final reaction without isolation of the intermediate from the reaction mixture. This simple one-pot procedure finished a convenient and useful synthesis of the target N-[p-(dialkyl-L-glutamatecarbonyl)-benzyl]lactobionamides. The phase-transition temperature of glycolipids was shown to greatly depend on the structure between the hydrophilic moiety and the hydrophobic segment of the glycolipids. The yield of proteins of lipases coated with the glycolipids containing disaccharides remarkably increased with alkyl-chain length, which was higher than that with glycolipids containing monosaccharides. The yields were also closely correlated to the origin of the lipases. The enzymatic reactivity of lipid-coated lipase PS was seldom affected by the hydrophobic segment of lipids, but its enantioselectivity was mainly affected by the hydrophilic moiety of lipids.
Amides↗
Regulation of CCAAT/enhancer-binding protein family members by stimulation of glutamate receptors in cultured rat cortical astrocytes.
Regulation of mRNA levels, DNA binding activities, and phosphorylation of CCAAT/enhancer-binding protein (C/EBP) family members by stimulation of glutamate receptors were studied in cultured rat cortical astrocytes. Indirect immunofluorescence and immunoblot analyses with specific antibodies to C/EBP family members revealed that both C/EBPbeta and C/EBPdelta but not C/EBPalpha are expressed in the nuclei of astrocytes. After exposure to glutamate, C/EBPbeta mRNA levels increased within 10 min, reached the maximal level at about 1 h, and returned to the basal level within 6 h. In contrast, C/EBPdelta mRNA levels decreased by 6 h and were recovered within 12 h. These changes in mRNA levels were accompanied by an increase and a decrease in proteins for C/EBPbeta and C/EBPdelta, respectively. Elevation of C/EBPbeta mRNA levels by glutamate treatment required an increase in intracellular Ca2+ concentration and depended on activations of protein kinase C and calmodulin-dependent protein kinases. Gel mobility shift analysis using nuclear extracts from the glutamate-treated cells showed increases in C/EBP site binding activities 2 h after the exposure to glutamate. Moreover, glutamate stimulated phosphorylation of C/EBPbeta in 32P-labeled astrocytes in a Ca2+-dependent manner. These results suggest that glutamate regulates functions of C/EBP family members in brain astrocytes through changes in mRNA levels of C/EBPbeta and C/EBPdelta as well as through phosphorylation of C/EBPbeta.
Animals↗
Synthesis of glycolipids: dialkyl N-[N-(4-lactonamidobutyl)succinamoyl]-L-glutamates.
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Galactolipids↗
A role of Ca2+/calmodulin-dependent protein kinase II in the induction of long-term potentiation in hippocampal CA1 area.
Long-term potentiation (LTP) in the CA1 area of the hippocampus is considered to be a synaptic model for learning and memory. The induction of LTP is initiated by activation of the NMDA glutamate receptor in the postsynaptic membrane and a subsequent increase in Ca2+ -influx into the neurons following glutamate release. The action of Ca2+ has been proposed to be mediated by Ca2+ -dependent protein kinases. Recent studies indicate that, among the protein kinases, Ca2+/calmodulin-dependent protein kinase II is implicated in the induction of LTP in the hippocampus.
Animals↗
CaM kinase II in long-term potentiation.
The observation that autophosphorylation converts CaM kinase II from the Ca(2+)-dependent form to the Ca(2+)-independent form has led to speculation that the formation of the Ca(2+)-independent form of the enzyme could encode frequency of synaptic usage and serve as a molecular explanation of "memory". In cultured rat hippocampal neurons, glutamate elevated the Ca(2+)-independent activity of CaM kinase II through autophosphorylation, and this response was blocked by an NMDA receptor antagonist, D-2-amino-5-phosphonopentanoate (AP5). In addition, we confirmed that high, but not low frequency stimulation, applied to two groups of CA1 afferents in the rat hippocampus, resulted in LTP induction with concomitant long-lasting increases in Ca(2+)-independent and total activities of CaM kinase II. In experiments with 32P-labeled hippocampal slices, the LTP induction in the CA1 region was associated with increases in autophosphorylation of both alpha and beta subunits of CaM kinase II 1 h after LTP induction. Significant increases in phosphorylation of endogenous CaM kinase II substrates, synapsin I and microtubule-associated protein 2 (MAP2), which are originally located in presynaptic and postsynaptic regions, respectively, were also observed in the same slice. All these changes were prevented when high frequency stimulation was applied in the presence of AP5 or a calmodulin antagonist, calmidazolium. Furthermore, in vitro phosphorylation of the AMPA receptor by CaM kinase II was reported in the postsynaptic density and infusion of the constitutively active CaM kinase II into the hippocampal neurons enhanced kainate-induced response. These results support the idea that CaM kinase II contributes to the induction of hippocampal LTP in both postsynaptic and presynaptic regions through phosphorylation of target proteins such as the AMPA receptor, MAP2 and synapsin I.
2-Amino-5-phosphonovalerate↗
Anteriorly located anus: is constipation caused by abnormal location of the anus?
Anteriorly located anus (ALA) is frequently associated with severe constipation accompanied by defecation pain. Between 1988 and 1994, the authors treated 27 children (26 girls, 1 boy; age range, 0 to 11 years) to surgically correct ALA. The operation was performed according to a uniform protocol to longitudinally divide the internal sphincter muscle from the anal skin level to 2 cm above the dentate line on the posterior wall of the anorectum. For anal reconstruction, any of the conventional procedures was employed. Twenty-two of the 27 patients have had follow-up in our clinic for 12 months to 6 years (mean, 2.75 years). Eighteen are completely free of constipation and defecation pain and have regular spontaneous bowel movements. The other four require occasional use of enemas or laxatives. Anal incontinence did not occur in any patient. The results of this study suggest that abnormal function of the internal sphincter is the most likely cause of constipation or defecation pain in patients with ALA and that internal sphincterotomy is the cornerstone of surgical treatment.
Anal Canal↗
Button device for antegrade enema in the treatment of incontinence and constipation.
Antegrade enema through an appendicostomy is effective in improving the quality of life for patients with incontinence or severe constipation. For patients without an appendix, a conventional gastrostomy button was used to create a cecostomy (or ileostomy) that served as a port for the administration of enema solutions.
Adult↗