Effects of increased cholinergic activity on naming in aphasia.
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Acetylcholinesterase↗
Biomedical subjects
M Miyazaki
Publications and source records attributed to M Miyazaki.
Substituted 3-(phenylsulfonyl)-1-phenylimidazolidine-2,4-dione derivatives as novel nonpeptide inhibitors of human heart chymase.
A series of 3-(phenylsulfonyl)-1-phenylimidazolidine-2,4-dione derivatives have been synthesized and evaluated for their ability to selectively inhibit human heart chymase. The structure-activity relationship studies on these compounds gave the following results. The 1-phenyl moiety participates in a hydrophobic interaction where an optimum size is required. At this position, 3,4-dimethylphenyl is the best moiety for inhibiting chymase and showed high selectivity compared with chymotrypsin and cathepsin G. A 3-phenylsulfonyl moiety substituted with hydrogen-bond acceptors such as nitrile and methoxycarbonyl enhances its activity. Molecular-modeling studies on the interaction of 3-[(4-chlorophenyl)sulfonyl]-1-(4-chlorophenyl)-imidazolidine-2,4-dione (29) with the active site of human heart chymase suggested that the 1-phenyl moiety interacts with the hydrophobic P1 pocket, the 3-phenylsulfonyl moiety resides in the S1'-S2' subsites, and the 4-carbonyl of the imidazolidine ring and sulfonyl group interact with the oxyanion hole and the His-45 side chain of chymase, respectively. The complex model is consistent with the structure-activity relationships.
Binding Sites↗
Regulatory interactions in the recognition of endocytic sorting signals by AP-2 complexes.
Many plasma membrane proteins destined for endocytosis are concentrated into clathrin-coated pits through the recognition of a tyrosine-based motif in their cytosolic domains by an adaptor (AP-2) complex. The mu2 subunit of isolated AP-2 complexes binds specifically, but rather weakly, to proteins bearing the tyrosine-based signal. We now demonstrate, using peptides with a photoreactive probe, that this binding is strengthened significantly when the AP-2 complex is present in clathrin coats, indicating that there is cooperativity between receptor-AP-2 interactions and coat formation. Phosphoinositides with a phosphate at the D-3 position of the inositol ring, but not other isomers, also increase the affinity of the AP-2 complex for the tyrosine-based motif. AP-2 is the first protein known (in any context) to interact with phosphatidylinositol 3-phosphate. Our findings indicate that receptor recruitment can be coupled to clathrin coat assembly and suggest a mechanism for regulation of membrane traffic by lipid products of phosphoinositide 3-kinases.
Adaptor Protein Complex 1↗
Chymase is activated in the hamster heart following ventricular fibrosis during the chronic stage of hypertension.
Chronic pressure overload induces cardiac tissue remodeling. Chymase is known to regulate matrix metabolism and angiotensin II formation. In the present study, we investigated the pathophysiological functions of chymase in the pressure-overloaded hamster heart induced by a two-kidney, one-clip (2K1C) hypertension procedure. Fibrosis and apoptosis were observed in the pressure-overloaded hearts of 2K1C hamsters 32 weeks after clipping, but these histological changes were not detected at 16 weeks. Heart chymase-like activity of 2K1C hamsters at 32 weeks increased 5.2-fold compared with that at 16 weeks, while angiotensin-converting enzyme was not activated. Chymase might be involved in cardiac tissue remodeling during the chronic stage of hypertension.
Animals↗
Determination of peptides by high-performance liquid chromatography with laser-induced fluorescence detection.
Peptides were determined by high-performance liquid chromatography (HPLC) with laser-induced fluorescence detection. Detection was based on pre-column fluorescence derivatization of peptides with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) in acetonitrile (MeCN)-0.1 M borate buffer (pH 8.0) at 40 degrees C for 10 min. The peptide derivatives were separated on a reversed-phase column with trifluoroacetic acid-MeCN and determined fluorometrically at 530 nm with excitation at 470 nm. The method was applied to the determination of enkephalins in rat brain and to a degradation study of bradykinin in human plasma. Optimization of the reaction conditions and the use of a semi-micro-column (100 x 2 mm I.D., 2 microns) made the detection limit of the peptides as low as 5-10 fmol. The detection limits of enkephalin and bradykinin were 20 and 5 fmol, respectively, using HPLC with laser-induced fluorescence detection. The method was sensitive enough to permit the quantitative determination of opioid peptides and bradykinin in tissue and plasma samples.
4-Chloro-7-nitrobenzofurazan↗
The role of a lymphoid-restricted, Grb2-like SH3-SH2-SH3 protein in T cell receptor signaling.
We have characterized an SH3-SH2-SH3 linker protein that is prominently expressed in lymphoid tissues. This protein has 58% sequence identity to Grb2. An identical protein called Grap has been found in hematopoietic cells. In Jurkat cells, T cell receptor activation leads to the association of Grap with phosphoproteins p36/38 and, to a lesser degree, Shc. This interaction is mediated by the Grap SH2 domain, which has similar binding specificity to the Grb2 SH2 domain. Grap also associates via its SH3 domains with Sos, the Ras guanine nucleotide exchange factor; with dynamin, a GTPase involved in membrane protein trafficking; and with Sam68, a nuclear RNA-binding protein that serves as a substrate of Src kinases during mitosis. T cell activation effects an increase in Grap association with p36/38, Shc, Sos, and dynamin. Sam68 binding is constitutive. Phospholipase C-gamma1 and Fyn are also found in activated Grap signaling complexes, although these interactions may not be direct. We conclude that Grap is a prominent component of lymphocyte receptor signaling. Based on the known functions of bound effector molecules, Grap-mediated responses to antigen challenge may include endocytosis of the T cell receptor, cellular proliferation, and regulated entry into the cell cycle.
Adaptor Proteins, Signal Transducing↗
Neutrophil-mediated sinusoidal endothelial cell injury after extensive hepatectomy in cholestatic rats.
The aim of this study was to assess the hypothesis that hepatic failure after extensive hepatectomy in patients with obstructive jaundice (OJ) may be mediated by polymorphonuclear neutrophils (PMN). In the OJ group, rats underwent a partial hepatectomy of 78% after 2 weeks of cholestasis and subsequent external biliary drainage for 5 days. In the sham-operated control group, rats were partially hepatectomized 19 days after the sham surgery. The concentration of the serum cytokine-induced neutrophil chemoattractant (CINC), which is homologous with the growth-related oncogene (gro) product, a member of the human interleukin (IL)-8 family, and a major neutrophil chemotactic factor in rats, increased concomitantly with accumulation of PMNs in the hepatic sinusoids during cholestasis and subsequent external drainage. However, changes in the serum purine nucleoside phosphorylase (PNP)/alanine transaminase (ALT) ratio as a marker of sinusoidal endothelial cell (SEC) injury showed no significant differences between the two groups. Intercellular adhesion molecule-1 (ICAM-1) expression on SECs was not affected by cholestasis and external drainage. After partial hepatectomy, the serum CINC concentration immediately elevated more prominently in the OJ group than in the sham-operated control group, and accumulation of PMNs in the sinusoids was more obvious and prolonged in the former. ICAM-1 expression was enhanced in both groups with a peak between 24 and 48 hours after partial hepatectomy. At this peak period, a significantly higher PNP/ALT ratio was observed in the OJ group. These results suggest that accumulation of PMNs in the sinusoidal space and ICAM-1 expression on SECs might be closely associated with the development of SEC injury after extensive hepatectomy in cholestasis.
Alanine Transaminase↗
Pyruvate alleviates toxic effects of ethanol on cells in culture.
Cytotoxic effects of ethanol on cultured human hepatocytes and fibroblasts differed with the type of culture medium used. When cytotoxic effects of ethanol were compared between culture systems using either RPMI-1640 or Dulbecco's modified Eagle's medium (DMEM), the cytotoxicity was more prominent with the former medium than with the latter. A reduction of the cytotoxic effects appeared to be due to the pyruvate contained in DMEM. The protective effect of pyruvate against ethanol toxicity may be related to tricarboxylic acid (TCA) cycle activity because addition of malate to the medium also reduced the cytotoxic effects. Our results suggest that drug cytotoxicity testing in vitro must be done using various types of culture medium.
Cell Division↗
Concomitant administration of sodium dichloroacetate and vitamin B1 for lactic acidemia in children with MELAS syndrome.
Myoclonic seizures, intractable abdominal pain, and headaches resolved during the concomitant administration of sodium dichloroacetate and vita min B1 in two Japanese siblings with the MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike syndrome).
Acidosis, Lactic↗
Enhanced endothelial cell injury by activated neutrophils in patients with obstructive jaundice.
BACKGROUND/AIMS: A high incidence of complications has been documented in patients with obstructive jaundice after operations. Recent reports have revealed that neutrophils are involved in the mechanism causing postoperative complications. However, there are few reports investigating the interaction between neutrophils and endothelial cells in obstructive jaundice. The aim of this study was to evaluate neutrophil-mediated endothelial cell injury in patients with obstructive jaundice. METHODS: Patients were divided into three groups: those with normal liver, obstructive jaundice, and relief of obstructive jaundice. Neutrophils were isolated from patients individually. Human umbilical vein endothelial cells and neutrophils were co-cultured after addition of phorbol myristate acetate. The release of lactate dehydrogenase and thrombomodulin was measured in the medium. RESULTS: Lactate dehydrogenase and thrombomodulin were released in the co-culture medium, and Eglin C, which is an elastase inhibitor, reduced the release of lactate dehydrogenase and thrombomodulin in a dose-dependent manner. The release of lactate dehydrogenase and thrombomodulin in the group with relief of obstructive jaundice was significantly higher than in the group with normal liver. There was no significant difference between the group with obstructive jaundice and the group with normal liver. The elastase activity in neutrophil suspension was similarly higher in the group with relief of obstructive jaundice than in the group with normal liver. CONCLUSIONS: This study suggests that neutrophils in patients with obstructive jaundice are not activated before its relief. After relief of obstructive jaundice, neutrophils are strongly primed and have the potential to cause endothelial cell injury. The neutrophil "priming" in patients with obstructive jaundice may be associated with the frequent occurrence of postoperative complications.
Adult↗
Optimization of a polarized photometric detector equipped with a split-type flow cell and its analytical application to oligo-saccharides.
A novel, non-modulated polarimeter called a polarized photometric detector (PPD) was previously described by the authors. The PPD enables the measurement of the optical rotation of chiral compounds as a change in absorbance by placing two linear polarizers on either side of a flow cell of a conventional photometric detector. The present study describes the optimization of the conditions of PPD for highly sensitive detection of saccharides. To maximize the light intensity, the light balancing filter and slit were removed from the detector (Shimadzu model SPD-10AV). These modifications resulted in an approximately 15-fold increase in the incident light intensity when the maximum current was applied to the lamp. When this intense light was transmitted through the polarizers, the signal intensity followed the theoretical equation for phase angles up to around 1 rad. If the energy of the transmitted light was less than 700 mV, however, the baseline noise was too great to determine the chiral analyte accurately. Setting the phase angle between two polarizers at 50 degrees and the detection wavelength at 400 nm provided the most suitable conditions. This detector was applicable for the determinations of oligosaccharides in foodstuffs separated by HPLC using gradient elution.
Flow Injection Analysis↗
Inhibitory effect of monatepil maleate on acyl-CoA:cholesterol acyltransferase activity in the liver of cholesterol-fed Japanese monkeys.
We have previously demonstrated that monatepil maleate, AJ-2615, a new calcium antagonist endowed with alpha1-adrenoceptor blocking property, has antiatherosclerotic and plasma lipid-lowering effects in Japanese monkeys fed on a cholesterol-rich diet. To clarify the mechanisms on plasma lipid-lowering action, we investigated the effect of monatepil maleate in these monkeys on hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activity. Both ACAT activity and esterified cholesterol content in the livers of monkeys fed on a cholesterol-rich diet for 6 months significantly increased about 7- and 16-fold, respectively, as compared with those in monkeys fed on a standard diet. Monatepil maleate (30 mg/kg/day for 6 months, orally) inhibited the increases of ACAT activity and esterified cholesterol content by 51% and 71%, respectively. In in vitro experiments, monatepil maleate inhibited ACAT activity in a concentration-dependent manner, whereas it did not affect 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity. A kinetic analysis revealed that monatepil maleate was a noncompetitive type inhibitor of ACAT. Hepatic ACAT activity was significantly correlated to hepatic esterified cholesterol content (r = 0.775, P < .0001), to plasma very low density lipoprotein (VLDL) content (r = 0.765, P < .0001) and to plasma total cholesterol content (r = 0.573, P < .005) in the monkeys. These results suggest that ACAT-inhibiting effect of monatepil maleate plays an important role in the reduction of hyperlipidemia.
Animals↗
A prospective study of prognostic value of type IV collagenase activity in colorectal cancer tissue.
The purpose of this prospective study was to evaluate the prognostic value of the type IV collagenase (IVase) activity in colorectal cancer tissue on disease-free and overall survival in 31 colorectal cancer patients. The clinicopathologic factors studied for prognostic value were age, tumor location, tumor differentiation, preoperative serum levels of carcinoembryonic antigen, Dukes' stage, and IVase activity in colorectal cancer tissue. IVase activities in colorectal cancer tissue were significantly higher in the group of patients with recurrences than in the group without recurrences (P = 0.019). Patients with high IVase activity in colorectal cancer tissue had a significantly shorter disease-free survival (P = 0.0016) and overall survival (P = 0.022) time than those with low IVase activity. Univariate and multivariate analysis showed that significant prognostic factors for disease-free survival were Dukes' stage (P = 0.029, P = 0.046, respectively) and IVase activity status (P = 0.0016, P = 0.0026, respectively). With respect to overall survival, only IVase activity status provided significant predictive value in multivariate analysis (P = 0.041). This prospective study suggests that IVase activity is a valuable prognostic factor in colorectal cancer patients.
Adult↗
CSF beta-endorphin levels in patients with infantile autism.
We measured CSF levels of beta-endorphin, an opioid hormone, in 19 patients with infantile autism and in 3 patients with Rett syndrome, and compared them with control values. In infantile autism, CSF levels of beta-endorphin did not differ significantly from those of age-matched controls. There was no significant correlation between CSF levels and clinical symptoms, including self-injurious behavior, pain insensitivity, and stereotyped movement. However, CSF levels of beta-endorphin were significantly higher in the patients with Rett syndrome than in the control (p < .05). Data suggest that neurons containing beta-endorphin may not be involved in patients with infantile autism. Thus, there is no relationship between dysfunction of brain opioid and autism.
Autistic Disorder↗
In situ hybridization studies of matrix metalloproteinase-3, tissue inhibitor of metalloproteinase-1 and type IV collagen in diabetic nephropathy.
Progressive expansion of the mesangial matrix is one of the most characteristic histological features of diabetic nephropathy (DN). To determine the balance between the turnover and degradation of extracellular matrix (ECM) in renal tissue of patients with DN, we examined the expression of matrix metalloproteinase-3 (MMP-3), tissue inhibitor of metalloproteinase-1 (TIMP-1) and type IV collagen (IV-C) mRNAs using a high-resolution in situ hybridization. Patients were divided into three grades: mild (grade I), moderate (grade II) and severe (grade III) mesangial expansion and tubulointerstitial injury. The relationship between the expression of these mRNAs and degree of glomerular mesangial expansion and interstitial injury was also examined. Cells positive for each mRNA were observed in glomerular resident cells, including glomerular mesangial, epithelial and endothelial cells and cells of Bowman's capsule. A number of tubular epithelial cells and some infiltrating cells in the interstitium also expressed these mRNAs. The expression of MMP-3 mRNA and TIMP-1 mRNA was strongest in glomeruli of grade I and inversely correlated with mesangial expansion. In contrast, the expression of all three types of mRNA was correlated with the degree of interstitial injury. Our results indicate that IV-C, MMP-3 and TIMP-1 mRNAs are expressed in glomerular resident cells, tubular epithelial cells and infiltrating cells in renal tissue of DN, and suggest that their expression changes with the degree of mesangial expansion and interstitial injury. Altered expression of MMP-3 and TIMP-1 may be associated with the progression of DN.
Adult↗
Functional changes of rat brain microsomal membrane surface after learning task depending on dietary fatty acids.
Biochemical characteristics of brain microsomal membranes were examined before and after the brightness-discrimination learning tasks in rats that were fed either safflower oil (alpha-linolenate-deficient) or perilla oil (alpha-linolenate-sufficient) diets. We detected small changes in the chain elongation system for polyunsaturated fatty acids in microsomes, whereas no significant difference was detected in the inositol trisphosphate-induced calcium release and ATP-induced calcium uptake profiles of microsomes between the two dietary groups. The calcium ion-induced aggregation rate of microsomes was determined in both groups. We found that the aggregation rate of microsomes in the safflower oil group was significantly greater than that in the perilla oil group. The difference in susceptibility of microsomal membrane phospholipids to phospholipase A2 between the groups was obvious, and the amount of released fatty acids by phospholipase A2 from the perilla oil group microsomes was nearly half of that from the safflower oil group microsomes after the learning task. Susceptibility of sialic acids on the brain microsomal membranes to exogenous sialidase was different only after the learning task in the safflower and perilla oil groups. These results suggest that the biochemical characteristics of membrane surfaces of brain microsomes are affected significantly by the learning task itself in a dietary oil-dependent manner.
Animals↗
Aeromonas hydrophila necrotizing fasciitis and gas gangrene in a diabetic patient on haemodialysis.
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Aeromonas hydrophila↗
Biochemical and immunological characterization of deoxyhypusine synthase purified from the yeast Saccharomyces carlsbergensis.
Deoxyhypusine synthase catalyzes the NAD+-dependent formation of deoxyhypusine in the eIF-5A precursor protein by transferring the 4-aminobutyl moiety of spermidine. This enzyme has recently been shown to be essential for cell viability and growth of yeast [Sasaki, K., Abid, M.R., and Miyazaki, M. (1996) FEBS Lett. 384, 151 154]. We have purified and characterized the enzyme from the yeast Saccharomyces carlsbergensis. The yeast and recombinant enzymes had a specific activity of 1.21 to 1.26 pmol per min per pmol of protein, and recognized both the eIF-5A precursor proteins almost equally as judged from their similar K(m) and V(max) values. Size exclusion chromatography and SDS-PAGE indicated that the active form of the enzyme is a homotetramer consisting of 43-kDa subunits. The enzyme showed a strict specificity for its substrates, NAD+, spermidine and eIF-5A precursor protein. Among all the substrates tested, only NAD+ showed a protective effect against heat inactivation of the enzyme suggesting that NAD+ initiates some conformational change in the enzyme. NADH exhibited a strong non-competitive inhibition (product inhibition). Unexpectedly, FAD, FMN, and riboflavin showed a moderate competitive inhibition. The competitive inhibition by diamines was maximal with compounds resembling spermidine in carbon chain length. 1,3-Diaminopropane inhibited the enzyme strongly in a competitive manner (product inhibition). On the other hand, putrescine did not inhibit the enzyme or act as a substrate. A polyclonal antibody raised against the yeast recombinant enzyme specifically inhibited deoxyhypusine synthase activity. The cross-reactivity (by Western blotting) of this antibody with the crude extracts varied depending on the source, indicating species specificity.
Amino Acid Sequence↗