Renin in mouse but not in rat submandibular glands

Renin was found in the submandibular glands of male Quackenbush mice in concentrations higher than has been reported for any tissue of any strain or species. However, no renin-like activity could e detected in glands from male and female Wistar rats using either pH 5.8 or 7.4 for assay and a radioimmunoassay specific for renin's reaction product, angiotensin I. Rabbit submandibular glands contained renin.     

药物发现的先驱者格特鲁德B·埃利昂(1918～1999)

G·B·埃利昂（CertrudeBelleElion）是本世纪获得诺贝尔生理学与医学奖仅有6位女性中的一位。尽管这位合理药物设计的先驱完全应该为自己所取得的成就感到骄傲，但她一点不关心这类华丽词藻和周围气氛。她真正关心的是她认为会对疾病本身产生最有效治疗的最好技术。从她1983年退休到1999年2月21日81岁时突然去世为止，实际上她从未停止过工作，有不少人已认识到，她只是表面上退休而已。G·B·埃利昂1918年出生于纽约，她的父母来自立陶宛和俄罗斯。在10岁时她的祖父和母亲死于癌症，这是她记忆中印象最深刻的事件。1937年她从亨特女子…     

Perfluoroalkyl substances in the blood samples from a male population of Sweden

Temporal trends of perfluoroalkyl substances （PFASs） have been determined in the blood samples from several countries globally including a female population in Sweden recently, yet little is known about the time trends in the blood levels of these compounds in Swedish male populations over recent years. In this study, the fourteen target PFASs consisted of four perfluorosulfonates （PFSAs） and ten perfluorocarboxylates （PFCAs） in the whole blood samples, collected from 153 Swedish elderly men during the period between 2008 and 2010, were analyzed via ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）. As the dominant PFASs contaminants in the blood samples, perfluorooctane sulfo- nate （PFOS） showed the highest geometric mean （GM） at 8.5 ng/mL, ranging from 1.7 to 29 ng/mL, while blood perfluorooctanoic acid （PFOA） contained the GM of 1.8 ng/mL, ranging from 0.35 to 6.4 ng/mL. Both the levels of these two compounds were lower than those determined in the blood samples of Swedish elderly pop- ulations derived from the late 1990s. According to the temporal trend analysis, over the three years, the blood levels of PFOS in Swedish male populations declined 16 % per annum, while those of perfluoroundecanoic acid （PFUnDA） increased 6.1% per annum, which were con- sistent with those reported previously for the populations from other countries.     

An equivalency condition of nonsingularity in nonlinear semidefinite programming

<正> In this paper,an equivalency condition of nonsingularity in nonlinear semidefinite programming,which can be viewed as a generalization of the equivalency condition of nonsingularity for linearsemidefinite programming,is established under certain conditions of convexity.     

Substantial increase of protein stability by multiple disulphide bonds

Disulphide bonds can significantly stabilize the native structures of proteins. The effect is presumed to be due mainly to a decrease in the configurational chain entropy of the unfolded polypeptide. In phage T4 lysozyme, a disulphide-free enzyme, engineered disulphide mutants that crosslink residues 3-97, 9-164 and 21-142 are significantly more stable than the wild-type protein. To investigate the effect of multiple-disulphide bonds on protein stability, mutants were constructed in which two or three stabilizing disulphide bridges were combined in the same protein. Reversible thermal denaturation shows that the increase in melting temperature resulting from the individual disulphide bonds is approximately additive. The triple-disulphide variant unfolds at a temperature 23.4 degrees C higher than wild-type lysozyme. The results demonstrate that a combination of disulphide bonds, each of which contributes to stability, can achieve substantial overall improvement in the stability of a protein.     

Thyrotropin-releasing hormone does not inhibit lysine vasopressin-induced growth hormone secretion in normal men

Summary In order to establish whether thyrotropin-releasing hormone (TRH) inhibits lysine-vasopressin (LVP)-induced growth hormone (GH) release, six normal men were tested with LVP alone or in combination with TRH. LVP strikingly increased serum GH levels; this response was not altered by TRH. These results indicated that in man TRH is not involved in the control of GH secretion in response to LVP.     

Host tree unsuitability recognized by pine shoot beetles in flight

Summary In spring, the landing rate of flying European pine shoot beetles,Tomicus piniperda L., on injured Scots pine diminishes as colonization continues. This is due to olfactory cues that indicate progressive host degradation. Verbenone was shown to play a role in the beetle's recognition of this unsuitability of a formerly suitable host, since the compound was increasingly released from colonized tree sections as they aged, but not from uninfested sections. Also, the release of verbenone at natural rates in the forest inhibited the attraction of beetles to host monoterpenes.