Cyclic AMP elevation is sufficient to promote the survival of spinal motor neurons in vitro

The short-term survival of highly purified embryonic spinal motor neurons (SMNs) in culture can be promoted by many peptide trophic factors, including brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), fibroblast growth factor (FGF), glial-derived neurotrophic factor (GDNF), and hepatocyte growth factor (HGF). We have asked whether these peptides are sufficient to promote the long-term survival of purified E15 SMNs. Contrary to previous reports, we find that when SMNs are cultured in serum-free medium containing a single peptide trophic factor only approximately one-third of the cells survive for 3 d in culture. When multiple factors are combined, additive effects on survival are observed transiently, but by 7 d of culture the majority of SMNs has died. Surprisingly, when cAMP levels are elevated, the majority of SMNs extend processes and survive for 1 week in culture in the absence of peptide trophic factors, even in low-density cultures. A combination of five peptide trophic factors, together with cAMP elevation, promotes the long-term survival of most of the SMNs in serum-free culture for 3 weeks. These findings provide useful culture conditions for studying the properties of SMNs and have implications for the treatment of motor neuron diseases.     

Using a bilingual group support system

Differences in language and culture among participants in a meeting can present tremendous barriers to efficient and effective communication. Cultural and lingual barriers are becoming increasingly important issues to international managers as businesses continue to expand globally. This paper describes a group support system (GSS) which reduces many of these lingual and cultural barriers in groups composed of Spanish and English speakers.     

Recognition of core binding sites by bacteriophage integrases

Bacteriophage integrases promote recombination between DNA molecules that carry attachment sites. They are members of a large and widely distributed family of site-specific recombinases with diverse biological roles. The integrases of phages lambda and HK022 are closely related members of this family, but neither protein efficiently recombines the attachment sites of the other phage. The nucleotides responsible for this specificity difference are located close to the points of recombinational strand exchange, within an integrase binding motif called the extended core binding site. There are four imperfectly repeated copies of this motif in each set of phage attachment sites, but only two, B' and C, contain major specificity determinants. When these specificity determinants were replaced by the corresponding nucleotides from a site with the alternative specificity, the resulting mutant was recombined by both integrases. Thus, the determinants act by impeding recombination promoted by the non-cognate integrase. We found that identical nucleotide substitutions within different core site copies had different effects on recombination, suggesting that integrase does not recognize each of the extended core binding sites in the same way. Finally, substitution at several positions in lambda integrase with the corresponding HK022-specific amino acids prevents recombination of lambda attachment sites, and this defect can be suppressed in an allele-specific manner by appropriate substitutions of HK022-specific nucleotides in the extended core binding sites.     

Conversion of thyrotropin heterodimer to a biologically active single-chain

TSH and the gonadotropins, FSH, LH, and CG are a family of heterodimeric glycoprotein hormones composed of a common alpha-subunit noncovalently linked to a hormone specific beta-subunit. Assembly of alpha- and beta-subunits is essential for hormone-specific posttranslational modifications, receptor binding, and bioactivity. Structure-function studies of TSH and gonadotropins using site-directed mutagenesis can often affect folding, assembly, and secretion of the hormone. To circumvent these difficulties, recently, the gonadotropin heterodimers were converted to single chains. Here we converted the hTSH heterodimer to a biologically active single chain by genetically fusing the amino terminal end of the common alpha-subunit to the carboxyl terminal end of hTSHbeta in the presence or absence of hCGbeta carboxyl terminal peptide (CTP), which was used as a linker. Wild-type hTSH and the single chains were expressed in Chinese hamster ovary (CHO) cells, and they were efficiently secreted. Although the secretion rate of the single chain was 3-fold higher than that of hTSH wild-type. Moreover, the secretion of the single chain in the presence of the CTP linker was dramatically increased. On the other hand, receptor binding and in vitro bioactivity of the single chains were similar to that of hTSH wild-type. These data indicate the potential of the single chain approach to further investigate structure-function relationships of TSH.     

Proximal and distal gastric distension in normal subjects and H. pylori-positive and -negative dyspeptic patients and correlation with symptoms

Aim of the study was to analyze gastric distension with water in H. pylori-positive and -negative dyspeptic patients and normal subjects and the correlation with symptoms. Twenty dyspeptic patients and 19 normal subjects were studied. H. pylori was determined in each dyspeptic patient with the rapid urea test at endoscopy. Gastric distension was evaluated by real-time ultrasonography with the ingestion of stepwise-increasing amounts of water up to a total of 600 ml. During distension, the symptom score was evaluated as well. The proximal stomach was significantly smaller in dyspeptic patients than in healthy controls, at 100-600 ml water (P<0.01). A larger distal stomach was observed at 500 and 600 ml of water (P<0.01). The score of bloating and fullness was greater in dyspeptics than in controls at 300 and 600 ml of water distension. The symptoms score was linearly correlated with proximal and distal gastric measurements in dyspeptic patients and in controls. No significant difference was found in dyspeptic patients regarding the H. pylori status. In conclusion, dyspeptic patients show a defective adaptation of the whole stomach to water distension and an increased symptom perception score as compared to controls. H. pylori infection does not seem to be a determining factor in these observed findings.     

Bioactivity of extracts from gonadal tissue of the edible Australian purple sea urchin Heliocidaris erythrogramma

Dichloromethane (DCM), methanol (MeOH) and aqueous extracts of male gonadal tissue from Heliocidaris erythrogramma were screened for bioactivity. None of the extracts were antibacterial against Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli. The aqueous extract scavenged the reactive oxygen species (ROS), hydrogen peroxide (H₂O₂), but did not react with the hydroxyl radical (OH·) or with the stable free radical 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH·). No antioxidant potential was evident for the DCM and MeOH extracts. The extracts displayed various levels of anti‐inflammatory action in connection with inhibition of cyclooxygenase (ovine COX‐1 and COX‐2), but were insignificant inhibitors of lipoxygenase (soybean 15‐LO) pure enzyme. Anti‐inflammatory action related to reduction of leukotriene production by stimulated porcine neutrophils was affected only by the aqueous extract. The DCM and aqueous extracts, but not the MeOH extract, showed anti‐inflammatory activity in rats developing adjuvant‐induced polyarthritis. Overall, the DCM extract was 75% inhibitory of arthritis symptoms, and the aqueous extract was 55% inhibitory. Suppression of growth of the mouse leukaemic lymphoblastic (P388) cell line was evident for the DCM extract only. This extract was also able to exert a cytotoxic effect on the tumour cell line. For all extracts, no general cytotoxicity against isolated rat hepatocytes was observed. Copyright © 2007 Society of Chemical Industry     

Predicting phospholipidosis: a fluorescence noncell based in vitro assay for the determination of drug-phospholipid complex formation in early drug discovery

This paper describes for the first time, a high-throughput fluorescence noncell based assay to screen for the drug-phospholipid interaction, which correlates to phospholipidosis. Anionic amphiphilic phospholipids can form complexes in aqueous solution, and its critical micelle concentration (CMC) can be determined using the fluorescence probe N,N-dimethyl-6-propionyl-2-naphthylamine (Prodan). Upon interaction with drug candidates, this CMC may shift to a lower value due to the association between lipids and drug candidates, the stronger the interaction, the greater the shift. Metabolism of a drug can change the degree of phospholipidosis depending on the rate of metabolism and the nature of the metabolite(s). Our data from 45 drugs and metabolites of 10 drugs using this fluorescence approach demonstrate a good correlation with phospholipidosis as reported with human studies, in vivo testing, and cellular assays. This assay therefore offers a fast, reliable, and cost-effective screening tool for early prediction of the phospholipidosis-inducing potential of drug candidates.     

Community perception: The ability to assess the safety of unfamiliar neighborhoods and respond adaptively.

When entering an unfamiliar neighborhood, adaptive social decisions are dependent on an accurate assessment of the local safety. Studies of cities have shown that the maintenance of physical structures is correlated with the strength of ties between neighbors, which in turn is responsible for the crime level. Thus it should be theoretically possible to intuit neighborhood safety through the physical structures alone. Here we test whether people have this capacity for judging urban neighborhoods with 3 studies in which individuals observed photographs of unfamiliar neighborhoods in Binghamton, New York. Each study was facilitated by data collected during previous studies performed by the Binghamton Neighborhood Project studies. In the 1st study, observer ratings on neighborhood social quality agreed highly with reports by those living there. In the 2nd, a separate sample of participants played an economic game with adolescent residents from pictured neighborhoods. Players exhibited a lower level of trust toward adolescents from neighborhoods whose residents report lesser social quality. In the 3rd study, the maintenance of physical structures and the presence of businesses explained nearly all variation between neighborhoods in observer ratings (89%), whereas the specific features influencing play in Study 2 remained inconclusive. These and other results suggest that people use the general upkeep of physical structures when making wholesale judgments of neighborhoods, reflecting a adaptation for group living that has strong implications for the role of upkeep in urban environments. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

外加纳米铜对钧瓷釉层显微结构及呈色的影响

在钧瓷釉层中引入纳米级水溶性铜单质,经过同样烧制工艺煅烧后,钧瓷外观呈色和釉层微观结构都会发生明显变化.通过X-射线粉末衍射仪、扫描电子显微镜及X-射线能谱仪等检测手段,我们系统研究了铜元素的加入对钧瓷釉层显微结构及呈色的影响.结果表明:外加纳米铜单质的钧瓷烧制后,釉层由月白色变为天青色,同时釉层中二氧化硅晶体明显减少,釉层玻璃化;另外,铜元素可以在高温阶段与坯体及釉层中产生的二氧化碳、氧气、水蒸气等发生化合反应,减少气泡缺陷的产生.