Single injections of triazolam,a short-acting benzodiazepine,lengthen the period of the circadian activity rhythm in golden hamsters

Single injections of the benzodiazepine, triazolam, induce phase shifts and cause a lengthening of the circadian activity rhythm in the golden hamster. The effect of triazolam on period depends on the phase of injection, but is not dependent on the direction of the phase shifts. Triazolam injections caused increases in period that were associated with phase advances as well as phase delays in the activity rhythm. This relationship between triazolam-induced phase shifts and changes in period is different from the relationship between light-induced phase shifts and period changes.     

Secondary metabolites of the chemically rich ascoglossanCyerce nigricans

Summary Two new metabolites of an apparent propionate origin have been isolated from the organic extract of the ascoglossan molluscCyerce nigricans. The proposed structures for the new natural products are based on interpretation of their physical and spectral properties. The new compounds isolated lacked the potent ichthyodeterrent properties of the whole animal extract suggesting that other molecules are involved in the defense of this shell-less mollusc.     

Isoprenaline-like effects of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine on mechanical, biochemical and electrophysiological parameters in the mammalian heart

The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) mimicked the effects of isoprenaline on the force of contraction, the cAMP content and the slow Ca++ inward current (Isi) in isolated guinea pig papillary muscles. The results support the hypothesis that phosphodiesterase inhibitors and beta-adrenoceptor agonists exert their positive inotropic effects by increasing Isi via the common mediator cAMP.     

Verapamil和Propranolol对非胰岛素依赖型糖尿病透析患者物质代谢的影响

比较Ｖｅｒａｐａｍｉｌ和Ｐｒｏｐｒａｎｏｌｏｌ对患有胰岛素非依赖型糖尿病及轻度至中度高血压的透析患者的血糖和物质代谢的影响。方法：４６例患有非胰岛素依赖型糖尿病及轻度至中度高血压的透析患者，为德国福尔达市ＫｆＨ血透中心和柏林ＫｆＨ血透中心的透析病人。分别经Ｖｅｒａｐａｍｉｌ和Ｐｒｏｐｒａｎｏｌｏｌ治疗三个月后测空腹血糖、血红蛋白Ａ１ｃ、果酸、胰岛素、胆固醇和甘油三脂，同时记录透析前心率和血压。结果：Ｖｅｒａｐａｍｉｌ对血糖及物质代谢无不良影响，Ｐｒｏｐｒａｎｏｌｏｌ可引起血糖、果酸和血红蛋白Ａ１ｃ升高。结论：在糖尿病透析患者，Ｐｒｏｐｒａｎｏｌｏｌ具有引起和／或加重小动脉血管病病以及脑血管意外的危险性     

Structure of a human common cold virus and functional relationship to other picornaviruses

We report the first atomic resolution structure of an animal virus, human rhinovirus 14. It is strikingly similar to known icosahedral plant RNA viruses. Four neutralizing immunogenic regions have been identified. These, and corresponding antigenic sequences of polio and foot-and-mouth disease viruses, reside on external protrusions. A large cleft on each icosahedral face is probably the host cell receptor binding site.     

Biosynthesis of 1-alkenes in the defensive secretions ofTribolium confusum (Tenebrionidae); stereochemical implications

Summary The terminally unsaturated hydrocarbons of the defensive secretion ofTribolium confusum are biosynthesized from fatty acids by oxidative decarboxylation. The process involves an enantiospecific cleavage of the C–H bond of thepro-(S) C(3)–H atom and simultaneous decarboxylation of the acid into an 1-alkene and carbon dioxide via ananti-periplanar transition state geometry (anti-elimination). The stereochemistry of this biotranformation is identical in all respects with the same reaction in higher plants. The mechanism seems to be of general importance for the biosynthesis of many vinylic substructures of natural products from oxygen-containing precursors.     

Blocking of lectin-like adhesion molecules on pulmonary cells inhibits lung sarcoma L-1 colonization in BALB/c-mice

Summary Adhesion and inhibition experiments with pulmonary cells of BALB/c-mouse origin and syngeneic sarcoma L-1 cells indicated that L-fucose specific lectin-like adhesion molecules, presumably situated on pulmonary cell surfaces are (at least partly) responsible for the specificity of this cell-cell interaction. Addition of specific sugars and glycoconjugates (L-fucose and fucoidan, respectively) to the incubation medium evidently inhibited the adhesion process as quantified using radiolabelled tumor cells. Unspecific carbohydrates (e.g. D-galactose) did not affect the cellular interaction. In vivo, repeated administration of fucoidan (but not of unspecific glycoconjugates) significantly inhibited the settling of metastatic sarcoma L-1 cells in the lungs of BALB/c-mice. Therefore, when lectin-like adhesion molecules on pulmonary cells were blocked with competitive glycoconjugates, tumor cell colonization of the lung could be significantly inhibited.     

A validation study of a variable weighting algorithm for cluster analysis

De Soete (1986, 1988) proposed a variable weighting procedure when Euclidean distance is used as the dissimilarity measure with an ultrametric hierarchical clustering method. The algorithm produces weighted distances which approximate ultrametric distances as closely as possible in a least squares sense. The present simulation study examined the effectiveness of the De Soete procedure for an applications problem for which it was not originally intended. That is, to determine whether or not the algorithm can be used to reduce the influence of variables which are irrelevant to the clustering present in the data. The simulation study examined the ability of the procedure to recover a variety of known underlying cluster structures. The results indicate that the algorithm is effective in identifying extraneous variables which do not contribute information about the true cluster structure. Weights near 0.0 were typically assigned to such extraneous variables. Furthermore, the variable weighting procedure was not adversely effected by the presence of other forms of error in the data. In general, it is recommended that the variable weighting procedure be used for applied analyses when Euclidean distance is employed with ultrametric hierarchical clustering methods.