Impact of polymorphisms of beta2- and beta3-adrenergic receptor genes on longitudinal changes in obesity in early childhood.
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Child, Preschool↗
Biomedical subjects
S Iwama
Publications and source records attributed to S Iwama.
Stereocontrolled synthesis of a sphingomyelin methylene analogue as a sphingomyelinase inhibitor.
[reaction: see text]Efficient synthesis of a sphingomyelin methylene analogue, which was designed as a sphingomyelinase inhibitor, was stereoselectively achieved. The Hofmann rearrangement of the alpha-hydroxyethyl-beta-hydroxy amide 4 followed by the intramolecular oxazolidinone ring formation was one of the key steps.
Bacillus cereus↗
Cyclic peptide formation catalyzed by an antibody ligase.
Cyclic hexapeptides represent a class of compounds with important, diverse biological activities. We report herein that the antibody 16G3 catalyzes the cyclization of d-Trp-Gly-Pal-Pro-Gly-Phe small middle dotp-nitrophenyl ester (8a) to give c-(d-Trp-Gly-Pal-Pro-Gly-l-Phe) (11a). The antibody does not, however, catalyze either epimerization or hydrolysis. The resulting rate enhancement of the cyclization by 16G3 (22-fold) was sufficient to form the desired product in greater than 90% yield. In absolute rate terms, the turnover of 16G3 is estimated to be 2 min(-1). The background rate of epimerization of 8a was reduced from 10 to 1% and hydrolysis from 50 to 4% in the presence of 16G3. As expected, the catalytic effects of 16G3 were blocked by the addition of an amount of the hapten equal to twice the antibody concentration. We also synthesized three diastereomers of 8a: the d-Trp(1)-d-Phe(6) (8b), l-Trp(1)-l-Phe(6) (8c), and l-Trp(1)-d-Phe(6) (8d) hexapeptides as well as d-Trp'-l-Trp(6) (12) and d-Phe'-l-Phe(6) (13). As expected, the rate enhancement by 16G3 was greatest for 8a, because the stereochemistry of Trp(1) and Phe(6) matches that of the corresponding residues on the hapten used to induce the biosynthesis of 16G3. A model of the variable domain of 16G3 was generated from the primary sequence using the antibody structural database to guide the model construction. The resulting model provided support for some previously proposed interpretations of the kinetic data, while providing valuable new insights for others.
Antibodies, Catalytic↗
Novel ligands lacking a positive charge for the delta- and mu-opioid receptors.
Recently we reported using minilibraries to replace Lys(9) [somatostatin (SRIF) numbering] of the potent somatostatin agonist L-363,301 (c[-Pro-Phe-D-Trp-Lys-Thr-Phe-]) to generate the potent neurokinin receptor (NK-1) antagonist c[-Pro-Phe-D-Trp-p-F-Phe-Thr-Phe-]. This novel cyclic hexapeptide did not bind the SRIF receptor. Thus, a single mutation converted L-363,301, a SRIF agonist with potency ca. 2-8 times the potency of SRIF in laboratory animals,(24) into a selective NK-1 receptor antagonist with an IC(50) of 2 nM in vitro. During the screening of the same libraries for ligands of the delta-opioid receptor, we identified four compounds (1-4) which represent a new class of delta-opioid antagonists, some of which were also NK-1 receptor antagonists. The most potent delta-opioid antagonist, c[-Pro-1-Nal-D-Trp-Tyr-Thr-Phe-] (2), showed a K(e) value of 128 nM in the mouse vas deferens assay and a delta-receptor binding affinity constant of 152 nM in the rat brain membrane binding assay. These results are of interest because they represent a novel class of delta-opioid antagonists and, like two previously reported delta-opioid antagonists, they lack a positive charge. To examine further the requirement for a positive charge in the delta-opioid ligands, we prepared two analogues of the beta-casomorphin-derived mixed mu-agonist/delta-antagonist, H-Dmt-c[-D-Orn-2-Nal-D-Pro-Gly-] (7), in which we eliminated the positive charge either through formylation of the primary amino group (5) or by the deletion of this N-terminal amino group (6). These latter compounds proved to be delta-opioid antagonists with K(e) values in the 16-120 nM range, as well as fairly potent mu-opioid antagonists (K(e) approximately 200 nM). These six compounds provide the most convincing evidence to date that there is no requirement for a positive charge in mu- and delta-opioid receptor antagonists. In addition, cyclic hexapeptide 4 lacks a phenolic hydroxyl group. Taken together, these data suggest that the prevailing assumptions about delta- and mu-opioid receptor binding need revision and that the receptors for these opioid ligands have much in common with the NK-1 and somatostatin receptors.
Animals↗
Roles of asp126 and asp156 in the enzyme function of sphingomyelinase from Bacillus cereus.
To elucidate the roles of conserved Asp residues of Bacillus cereus sphingomyelinase (SMase) in the kinetic and binding properties of the enzyme toward various substrates and Mg2+, the kinetic data on mutant SMases (D126G and D156G) were compared with those of wild type (WT) enzyme. The stereoselectivity of the enzyme in the hydrolysis of monodispersed short-chain sphingomyelin (SM) analogs and the binding of Mg2+ to the enzyme were not affected by the replacement of Asp126 or Asp156. The pH-dependence curves of kinetic parameters (1/Km and kcat) for D156G-catalyzed hydrolysis of micellar SM mixed with Triton X-100 (1:10) and of micellar 2-hexadecanoylamino-4-nitrophenylphosphocholine (HNP) were similar in shape to those for WT enzyme-catalyzed hydrolysis. On the other hand, the curves for D126G lacked the transition observed for D156G and WT enzymes. Comparison of the values and the shape of pH-dependence curves of kinetic parameters indicated that Asp126 of WT SMase enhances the enzyme's catalytic activity toward both substrates and its binding of HNP but not SM. The deprotonation of Asp126 enhances the substrate binding and slightly suppresses the catalytic activity toward both substrates. Asp156 of WT SMase acts to decrease the binding of both substrates and the catalytic activity to HNP but not SM. From the present study and the predicted three-dimensional structure of B. cereus SMase, Asp126 was thought to be located close to the active site, and its ionization was shown to affect the catalytic activity and substrate binding.
Aspartic Acid↗
Design and synthesis of new secretory phospholipase A2 inhibitor of a phospholipid analog.
All stereoisomers of N-acyl-4,5-disubstituted oxazolidinone phospholipid analogs were synthesized by regio and stereoselective epoxide ring opening accompanied by introduction of an amino group. The (4R,5S)-derivative showed stronger inhibitory activity toward type II phospholipase A2 than the 4-substituted oxazolidinone phospholipid analog previously reported.
Drug Design↗
pH dependence of the reaction rate of p-bromophenacyl bromide and of the binding constants of Ca2+ and an amide-type substrate analog to bovine pancreatic phospholipase A2.
pH dependence of the chemical reaction rates of p-bromophenacyl bromide (BPB) and of the binding constants of Ca2+ to bovine pancreatic active- and pro-phospholipases A2 (PLA2s) was studied at 25 degrees C and ionic strength 0.2. The pH dependence curves of the reaction rates of BPB with both enzymes were biphasic. The amino acid residues participating in the two transitions were ascribed to His 48 and the N-terminal alpha-amino group for the active enzyme and to His 48 and Arg -1 for the proenzyme. The pH dependence curve of Ca2+ binding to the active enzyme was interpreted in terms of participation of Asp 49, His 48, and the alpha-amino group. On the other hand, the curve for the proenzyme was interpreted in terms of participation of Asp 49, His 48, and Arg -1. The Ca2+ and pH dependence of the binding constant of a potent competitive inhibitor, monodispersed (R)-2-dodecanoylamino-1-hexanol-phosphocholine (amide-PC), to bovine pancreatic active-PLA2 was also studied. The binding of amide-PC was markedly facilitated by Ca2+ binding to the enzyme, whereas that of a genuine substrate, monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC), was independent of Ca2+ binding. The pH dependence curve of the binding constant of the amide-PC showed one transition, and this was interpreted in terms of participation of His 48, whereas the binding of the diC6PC was independent of the ionization state of His 48. The difference in the Ca2+ dependence for the bindings of the diC6PC and amide-PC was considered to arise from the fact that the amide group of amide-PC can form a hydrogen bond with His 48, whereas the genuine substrate cannot form such a hydrogen bond.
Acetophenones↗
X-ray crystal structure determination and molecular dynamics simulation of prophospholipase A2 inhibited by amide-type substrate analogues.
X-ray crystal structures of bovine pancreas prophospholipase A2 (proPLA2) inhibited by two amide-type inhibitors, [(R)-2-dodecanoyl-amino-1-hexanolphosphocholine (DAHPc) and (R)-2-dodecanoylamino-1-hexanolphosphoglycol (DAHPg)], were determined to R = 0.208 and 0.215 using reflections with up to 2.1 A resolution, respectively. Both complex crystals lacked defined electron densities for the prosequence of the N-terminal and for a loop region consisting of residues 65-70, retaining the disordered feature observed in free proPLA2 despite stabilization due to complex formation. The polar and nonpolar moieties of the amide-type inhibitors were located in the calcium-binding pocket and in the N-terminal alpha-helical hydrophobic region of the enzyme, respectively. As for the amide group of the inhibitor, which is lacking in the true substrate, a strong hydrogen bond was formed between the NH of the inhibitor and the unprotonated N(delta1) atom of His-48, resulting in the tight binding of the inhibitor to proPLA2, as well as to PLA2. The 20-30 times more potent inhibitory activity of DAHPg than DAHPc toward PLA2 could be explained by hydrogen bond formation between the glycol OH of DAHPg and the carbonyl O of Asp-49. The seven residues of the N-terminal prosequence of proPLA2, though disordered, block the access of a water molecule to Ala-1 of PLA2 or change the hydrogen-bonding property of Ala-1 alpha-amino group, resulting in breakage of the water-mediated hydrogen-bond network which is commonly formed in PLA2. The results of molecular dynamics (MD) calculation in an aqueous solution at 300 K indicate that this, rather than the close contact between the prosequence and the residues 65-70 loop region, is the main reason why the latter region becomes flexible in proPLA2, compared with in PLA2.
Animals↗
Tooth pulp neurons in the caudal medulla oblongata of the cat.
The medulla oblongata caudal to the obex was explored for neurons responsive to tooth pulp (TP) stimulation in cats. Four different subclasses of TP neurons were found. The latter included TP specific (TPS) neurons, trigeminal wide dynamic range (trigeminal WDR) neurons with TP input, trigeminal subnucleus reticularis ventralis (trigeminal SRV) neurons with TP input and convergent reticular formation (convergent RF) neurons with TP input. TPS neurons were located in the dorsal marginal rim of the trigeminal subnucleus caudalis, i.e., in the marginal layer or the outer zone of substantia gelatinosa. WDR neurons with TP input were found in the neck region of medullary dorsal horn which corresponds to the lateral part of subnucleus reticularis dorsalis (SRD). Trigeminal SRV neurons with TP input were located in the lateral part of SRV. Convergent RF neurons with TP input were found in the middle third of the caudal bulbar RF consisting of SRD and SRV. Both TPS neurons and WDR neurons with TP input included trigeminothalamic neurons as evidenced by the antidromic activation from the nucleus ventralis posteromedialis of the contralateral thalamus. A significant proportion of both trigeminal SRV and convergent RF neurons with TP input were antidromically activated by stimulation of the nucleus centralis lateralis of the contralateral thalamus. The former two subclasses may subserve the sensory-discriminative aspect of toothache, while the latter two subclasses, the emotional-motivational aspect.
Animals↗
Elevated plasma levels of matrix metalloproteinase-9 (92-kd type IV collagenase/gelatinase B) in hepatocellular carcinoma.
BACKGROUND: Matrix metalloproteinase 9 (MMP-9), a 92-kd gelatinase/type IV collagenase, has been implicated as playing an important role in cancer invasion and metastasis. A previous study showed that serum type IV collagenase activity correlated with metastasis by hepatocellular carcinoma (HCC). The aims of this study were to determine the plasma levels of immunoreactive MMP-9 in patients with HCC and to compare the levels with the clinical features including vascular invasion. PATIENTS AND METHODS: This study included 100 patients with HCC, 21 patients with chronic hepatitis (CH), 24 patients with liver cirrhosis (LC), and 138 healthy control subjects. Plasma MMP-9 levels were measured with a specific one-step sandwich enzyme immunoassay. RESULTS: Plasma MMP-9 levels in HCC (62 [33 to 130 ng/mL] median [25%, 75%], 13 to 660 ng/mL, minimum, maximum) were significantly elevated compared with those in normal controls (36 [25 to 45], range, 2.8-70 ng/mL), in CH (28 [18 to 30], 13 to 66 ng/mL) and in LC (35 [26 to 58], 16 to 86 ng/mL) (P < .0000001; P = .0000003; and P = .00205, respectively). When the cut-off level was defined as 60 ng/mL from a receiver operating characteristic curve, plasma MMP-9 concentrations had a sensitivity of 53% and a specificity of 89% for the detection of HCC from CH and LC. The levels were significantly higher in HCC patients with macroscopic portal venous invasion (79 [36 to 160], 15-660 ng/mL) than those without the invasion (44 [27 to 80], 13 to 210 ng/mL) (P = .00726). Plasma MMP-9 levels in patients with HCC were not correlated with tumor number, size, volume, or serum alpha-fetoprotein levels. CONCLUSIONS: The present data suggest that plasma MMP-9 levels can be a candidate for a novel marker for HCC. The levels appear to reflect its potential and ongoing activity of vascular invasion. A long-term follow-up of the patients will be necessary to determine whether increased plasma MMP-9 levels are predictive of more invasive and metastatic HCC.
Adult↗
Epitaxial growth and critical currents in (013)/(103)- and (110)-oriented YBa2Cu3Ox films.
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Journal Article↗
New phospholipase A2 inhibitor: synthesis and inhibition mechanism of oxazolidinone phospholipid analog.
(R)-3-Dodecanoyl-4-phosphatidylcholino-hydroxymethyl-2-oxazolidino ne (7), which is a new glycerophospholipid analog, was synthesized starting from (S)-glycidol through a 4-alkylsilyoxymethyl derivative and N-acyl-4-hydroxymethyl derivative. The cyclic amide analog 7 showed strong inhibitory activity toward both Group I and II PLA25, but the inhibitory potency of 7 was slightly weaker than that of the linear amide analog (R)-1, which had been developed by de Haas et al. (Biochem. Biophys. Acta 1990, 1043, 67). The interactions of 7 with human secretory PLA2 was investigated by computer modeling in comparison with those of the linear amide analog 1. The results of the computer modeling were very compatible with those of the inhibitory activities toward PLA2S, and the both results showed that the binding mode of the oxazolidinone analog 7 was very similar to that of the genuine substrate and was different from that of the linear amide analog 1.
Computer Simulation↗
Binding mode of phospholipase A2 with a new type of phospholipid analog having an oxazolidinone ring.
Inhibition of phospholipases A2 (PLA2s) by a new type of monodispersed phospholipid analog, 3-dodecanoyl-4-phosphatidylcholinohydroxymethyl-2-oxazolidinone (oxazolidinone-PC), was investigated by the pH stat assay method using monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC) as the substrate. The PLA2s used were those from bovine pancreas and cobra (Naja naja atra) venom (Group I) and from Japanese mamushi (Agkistrodon halys blomhoffii) venom (Group II). This new-type substrate analog was shown to inhibit competitively both types of venom and bovine pancreatic enzymes by binding to the active site in a similar manner to the carboxamide-type analog 2-dodecanoyl-amino-1-hexanol-phosphocholine (amide-PC). The binding of a stereoisomer, (R)-amide-PC, to N. naja atra (Group I) and A. halys blomhoffii (Group II) PLA2s was facilitated by the binding of Ca2+ to the enzymes. On the other hand, the binding of (R)-oxazolidinone-PC to the N. naja atra (Group I) enzyme was found to be independent of Ca2+ binding, while its binding to the A. halys blomhoffii (Group II) enzyme was markedly facilitated by the binding of Ca2+ to the enzyme. The binding of (R)-amide-PC to N. naja atra PLA2 (Group I) was markedly influenced by the ionization state of the catalytic residue His 48, whereas the binding of (R)-oxazolidinone-PC was found to be practically independent of the ionization state of this residue.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
A randomized trial of intrahepatic arterial infusion of 4'-epidoxorubicin with Lipiodol versus 4'-epidoxorubicin alone in the treatment of hepatocellular carcinoma.
We conducted a prospective randomized trial to evaluate the efficacy of Lipiodol in intrahepatic arterial infusion chemotherapy for patients with hepatocellular carcinoma (HCC). A total of 38 patients with unresectable HCCs and underlying cirrhosis were entered in this trial, and 36 of them were evaluable. Every 4 weeks, 17 patients received 70 mg of 4'-epidoxorubicin (epirubicin) alone (group A), whereas 19 patients received a Lipiodol emulsion containing the same dose of epirubicin (group B) through the hepatic artery. A tumor response (CR+PR) was observed in 12% of group A patients and in 42% of group B patients. The group B patients showed a significantly higher response rate than the group A patients. There was a tendency for an increased duration of survival (P = 0.09) in the group B patients. These results suggested that the infusion of the Lipiodol emulsion with epirubicin was more effective than epirubicin alone for the treatment of these patients with HCC.
Aged↗
Role of Ca2+ in the binding of phospholipase A2 with a monomeric substrate and with its amide-type analog.
Effects of Ca2+ on the kinetic parameters for the hydrolysis of monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC), catalyzed by Group I phospholipases A2 (PLA2s) from Pseudechis australis, Naja naja atra, and bovine pancreas and by Group II enzymes from Vipera russelli russelli, Agkistrodon halys blomhoffii, and Trimeresurus flavoviridis, were studied by the pH-stat assay method at 25 degrees C, pH 7.5-8.2, and an ionic strength of 0.1 or 0.2 in the absence or presence of an amide-type substrate analog, 2-dodecanoyl-amino-1-hexanol-phosphoglycol. The binding of genuine substrate to the Group II enzymes and that of its analog to the Groups I and II enzymes were markedly facilitated by the binding of Ca2+ to the enzymes. On the other hand, the binding of genuine substrate to the Group I enzymes was found to be independent of the Ca2+ binding. The former result suggests that the structures of the Group II enzyme-genuine substrate complexes and both types of enzyme-analog complexes are generally stabilized by the Ca2+ binding, whereas the latter indicates that the structures of the Group I enzyme-genuine substrate complexes are already similar to those of their Ca2+ complexes and that, therefore, these enzyme-substrate interactions are independent of the Ca2+ binding.
Amides↗
Crystallization and preliminary X-ray study of Agkistrodon halys blomhoffii phospholipase A2 complexed with a specific inhibitor.
Phospholipase A2 from the venom of Agkistrodon halys blomhoffii has been crystallized as a complex with a specific inhibitor, (S)-2-dodecanoyl-amino-3-hexanol-1-phosphoglycol. The complex crystals belong to the hexagonal space group, P6(1)22 (or P6(5)22), with cell dimensions of a = b = 61.13 A, and c = 173.15 A. The diffraction extends to at least 2.3 A resolution.
Animals↗
Combined hepatocellular-cholangiocarcinoma with variable sarcomatous transformation.
An adult case of combined hepatocellular-cholangiocarcinoma with variable sarcomatous changes is presented. Histologically, the tumor was composed of hepatocellular carcinoma, cholangiocarcinoma, and sarcomatous portions, including spindle-shaped, pleomorphic, and osteoplastic varieties. There was a transitional cell form between the carcinoma and sarcomatous cells. These tumor elements showed both independent and concurrent metastases. Immunohistochemical examination for keratin revealed positive staining in the tumor cells except for osteoplastic immature cells, whereas vimentin had positive results only in some sarcomatous cells. On the basis of these findings, the possibility of sarcomatous transformation of combined hepatocellular-cholangiocarcinoma was discussed.
Adenoma, Bile Duct↗
[A case of rupture of a posterior pancreaticoduodenal artery aneurysm].
A 75 year old man complaining of right upper abdominal pain was admitted to our hospital. He became shocked with hypotension and cold sweat, and immediately underwent operation. Laparotomy revealed massive hemorrhage in the retroperitoneal region, particularly in the right upper space. It was derived from the rupture of the posterior pancreaticoduodenal artery aneurysm. The arterial trunk was ligated above and below the aneurysm and the aneurysmectomy was carried out. The patient recovered and was discharged from the hospital 56 days after operation. There was no other visceral artery aneurysm and the etiology of this aneurysm was unknown. Four cases of pancreaticoduodenal artery aneurysm have been reported in Japan and three of them were operated, but this is the first surgically resected case for the rupture of pancreaticoduodenal artery aneurysm with success.
Aged↗