An extensive quantum chemical study of the potential energy surface (PES) for all possible isomerization and dissociation reactions of CH3CN is reported at the DFT (B3LYP/6-311++G(d,p)) and CCSD(T)/ ...cc-pVTZ//B3LYP/6-311++G(d,p) levels of theory. The pathways around the equilibrium structures can be discovered by the scaled hypersphere search (SHS) method, which enables us to make a global analysis of the potential energy surface for a given chemical composition in combination with a downhill-walk algorithm. Seventeen equilibrium structures and 59 interconversion transition states have been found on the singlet PES. The four lowest lying isomers with thermodynamic stability are also kinetically stable with the lowest conversion barriers of 49.69−101.53 kcal/mol at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) level, whereas three-membered-ring isomers c-CH2NCH, c-CH2CNH, and c-CHNHCH can be considered as metastable intermediates which can further convert into the low-lying chainlike isomers and higher lying acyclic isomers with the lowest conversion energies of 21.70−59.99 kcal/mol. Thirteen available dissociation channels depending on the different initial isomers have been identified. A prediction can be made for the possible mechanism explaining the migration of a hydrogen atom in competition with the CC bond dissociation. Several new energetically accessible pathways are found to be responsible for the migration of the hydrogen atom. The present results demonstrate that the SHS method is an efficient and powerful technique for global mapping of reaction pathways on PESs.
This study presents the results of fine needle aspiration cytology in a series of 26 consecutive children with neuroblastic tumours. The cytological spectrum varied from undifferentiated small tumour ...cells to mature ganglion cells in a fibrillar background. In 24 children with neuroblastic tumours at onset the cytological diagnosis was correct in 21 cases, whereas two aspirates yielded nondiagnostic necrotic material and a fibrillar material without tumour cells, respectively. One necrotic lymph node aspirate was initially incorrectly diagnosed as lymphoma, but the diagnosis was later revised to neuroblastoma. Suspected signs of disease progression or relapses were confirmed (n = 9) or ruled out (n = 1) using aspiration cytology. The diagnostic accuracy in the complete series was 97% (31/32) in cases with adequate smears. Immunocytochemistry confirmed the cytological diagnosis in 14 of 15 cases and was decisive in one. Elevated catecholamine metabolites in urine was detected in all children with a cytological diagnosis of neuroblastoma. General anaesthesia was only performed when coincidental invasive investigations (n = 13) were to be carried out or if the aspiration was intrathoracic (n = 6). It is concluded that aspiration cytology in conjunction with immunocytochemistry offers a safe, rapid and accurate diagnostic method which may be useful, together with analyses of catecholamine metabolites in urine, in the clinical management of children with neuroblastic tumours.
Neisseria gonorrhoeae strains are susceptible to fluoroquinolones, and selected fluoroquinolones are recommended as primary therapy for uncomplicated gonorrhoea. However, fluoroquinolone treatment ...failures associated with resistance to these agents and the emergence of strains with decreased susceptibilities to fluoroquinolones have been reported. Recently, the mechanisms of quinolone resistance in N. gonorrhoeae have been identified and characterized. The alteration of the GyrA subunit of DNA gyrase has a central role in conferring fluoroquinolone resistance on N. gonorrhoeae strains, while the change of the ParC subunit of topoisomerase IV has a complementary role. Serotypic characterization studies have demonstrated that the majority of the strains with decreased susceptibilities to fluoroquinolones isolated from different regions around the world are distributed in various serotypes in serogroup WII/III. However, there have been no studies reporting the relationship between serological classification and alterations in GyrA and ParC proteins in quinolone-resistant isolates of N. gonorrhoeae. In this study, we serotyped 31 isolates with quinolone-resistance-associated alterations in GyrA and ParC proteins to assess whether alterations in these proteins were associated with one or various clones in the gonococcal population.
Japanese cedar (
Cryptomeria japonica, CJ) pollen has been known to cause atopic dermatitis in dogs in Japan. However, since the mechanism of the CJ antigen recognition is not well understood in ...dogs, it is difficult to develop effective immunotherapy for atopic dermatitis caused by sensitization to CJ pollen. In order to aim at development of a peptide immunotherapy, we tried to identify T-cell epitopes of a major allergen of CJ pollen, Cry j 1, in dogs sensitive to CJ pollen allergen. Peripheral blood mononuclear cells (PBMCs) obtained from 22 dogs experimentally sensitized to CJ pollen allergen and 5 atopic dogs sensitive to CJ pollen allergen were used for mapping of T-cell epitopes of Cry j 1 using 35 kinds of synthesized overlapping peptides of Cry j 1. Reactive peptides were identified based on the results of blastogenic responses of PBMCs against the peptides when the stimulation indices were beyond 2.0. Three reactive peptides were identical in a relatively high population of experimental dogs, which were Nos. 8 (p71–90) (41%), 10 (p91–110) (50%), and 11 (p101–120) (41%). It was considered that these synthesized peptides should contain T-cell epitopes of Cry j 1 in the dogs. However, there were no reactive peptides identical among the five atopic dogs spontaneously sensitive to CJ pollen. The population of dogs experimentally sensitized to CJ pollen antigen will be used in order to investigate effects of a peptide immunotherapy using the reactive peptides. The results in atopic dogs sensitive to CJ pollen antigen will also provide useful information on necessity to develop a tailor-made immunotherapy using reactive peptides in each dog.
Enhanced locomotory activity (ELA), such as wandering, is a normal behavior that occurs at the end of the larval stage in lepidopteran (butterflies and moths) insects. Baculovirus infection can also ...induce ELA in lepidopteran larvae. The belief is that the virus induces this behavior to increase its transmission Goulson, D. (1997) Oecologia 109, 219-228. Here we show that a baculovirus-encoded protein tyrosine phosphatase (PTP) gene (ptp) induces ELA that is activated by light. ELA was induced in silkworm Bombyx mori infected with the baculovirus B. mori nucleopolyhedrovirus (BmNPV) beginning at approximately equal to 3.75 days postinfection (p.i.) and continued until 4.75 days p.i. The intensity of the ELA was dramatically reduced immediately before death at 5.25 days p.i. Light activated the intensity of the ELA by approximately equal to 3-fold, and larvae with ELA showed positive phototropism. ELA was not induced in larvae of B. mori infected with a BmNPV ptp knockout mutant (BmPTPD). However, when a silkworm-derived ptp gene (Bmptp-h) was inserted into BmPTPD, ELA was partially recovered. Bmptp-h was identified from silkworms at 2 days after the start of the natural wandering stage. The deduced amino acid sequence of Bmptp-h showed 48.2% identify (80.7% similarity) to the deduced amino acid sequence of BmNPV ptp. On the basis of the high homology and larval stage at which Bmptp-h was isolated, we postulate that the modern baculovirus may have acquired its ptp gene from an ancestral host and that this gene was selectively maintained because it increases virus transmission.
N-Ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine (NOC12), a nitric oxide donor, 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite (ONOO
−), and peroxynitrite induced cell death ...accompanied by DNA fragmentation in human neuroblastoma SH-SY5Y cell cultures. Morphine prevented the cell death induced by SIN-1 or peroxynitrite, but not that induced by NOC12. The protective effect of morphine was concentration-dependent (10–100 μM), but was not antagonized by naloxone. The selective ligands for opioid receptor subtypes,
d-Ala
2,
N-Me-Phe
4, Gly-ol
5enkephalin (DAMGO, μ-opioid receptor agonist),
d-Pen
2,5enkephalin (DPDPE, δ-opioid receptor agonist) and
trans-(±)-3,4-dichloro-
N-methyl-
N-(2-1-pyrrolidinyl-cyclohexyl)benzeneacetamide (U-50488, κ-opioid receptor agonist) even at the concentration of 100 μM did not prevent the cell death induced by SIN-1. From measurement of the absorbance spectrum of peroxynitrite, the decomposition of peroxynitrite in 0.25 M potassium phosphate buffer (pH 7.4) was very rapid and complete within seconds. However, the absorbance was very stable in the presence of morphine. In addition, morphine inhibited peroxynitrite-induced nitration of tyrosine in a concentration-dependent manner. These results indicate that morphine rapidly reacts with peroxynitrite. The present study showed that morphine prevented peroxynitrite-induced cell death through its direct scavenging action, suggesting that morphine can protect cells against damage caused by peroxynitrite.
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