朝藿素D的分离和结构

从朝鲜淫羊藿(Epimedium koreanum)地上部分分离得到一新黄酮成分(I)和一已知化合物(II)。经光谱解析,证明I的结构为5,7,3',4'-tetrahydroxy-5'-prenylflavone,命名为朝藿素D(epimedokoreanin D);II为2-hydroxy-3,4,6,7-tetramethoxy-9,10-dihydrophenanthren。     

Leadership in the nursing unit: relationships with nurses' well-being

The head nurse occupies an important position in the nursing unit Concerning leadership style, a distinction is traditionally made between consideration and initiating structure Sometimes a third style is distinguished as well, namely 'production-orientated' leadership In a study of 561 nurses from 16 general hospitals in The Netherlands, the influence of two leadership styles upon the reactions of nurses (job satisfaction, experienced meaningfulness, health complaints and absenteeism) to their work situations was examined, namely the styles of social (i e consideration) and instrumental leadership (a combination of the styles initiating structure and production-onentated) The separate effects of the two styles were studied, as well as the connection between combinations of leadership styles and reactions The results indicate that social leadership contributes positively to nurses' reactions to their job Instrumental leadership, on the other hand, leads to health complaints From the analyses of combinations of leadership styles it appears that nurses are most satisfied if the head nurse pays much attention to both dimensions of leadership For health complaints, a tendency in this directions is also found Finally, it becomes clear that nurses with a great need for autonomy prefer a different type of leadership from nurses with little need for autonomy     

Inhibition of sympathetic preganglionic discharges by epinephrine and α-methylepinephrine

The present study was undertaken to determine the effect of iontophoretic applications of epinephrine (E) and its derivative α-methylepinephrine (mE) on the discharges of sympathetic preganglionic neurons (SPNs).Spontaneously active SPNs located in thoracic segment T2 were antidromically identified in White Carneaux pigeons anesthetized with urethane and immobilized with purified α-cobratoxin.All SPNs tested were inhibited by E, mE, several other catecholamines, clonidine, GABA, glycine and morphine.The inhibitory effects of E and mE but not those of GABA were antagonized by iontophoretic applications of the preferential α₂-antagonists piperoxane and yohimbine, but not by the α₁-antogonist praxosin or the β-antagonist sotalol when similarly applied.The inhibitory effects of GABA, glycine and morphine were respectively antagonized by bicuculline methiodide, strychnine and naloxone, but these antagonists failed to alter the action of E.It is concluded that (1) epinephrine and its α-methyl derivative inhibit the discharges of SPNs via the activation of α₂-receptors and(2) the epinephrine-induced inhibition does not result from the secondary release of GABA, glycine or opioid peptides from afferent terminals or interneurons.     

Platelet adhesion to collagen types I through VIII under conditions of stasis and flow is mediated by GPIa/IIa (alpha 2 beta 1-integrin)

Platelet adhesion to fibrillar collagens (types I, II, III, and V) and nonfibrillar collagens (types IV, VI, VII, and VIII) was investigated in the presence of physiologic concentrations of divalent cations under conditions of stasis and flow. Under static conditions, platelet adhesion was observed to collagen types I through VII but not to type VIII. Under flow conditions, platelet adhesion to collagen types I, II, III, and IV was almost independent of shear rates above 300/s. Collagen type V was nonadhesive. Platelet adhesion to collagen type VI was shear rate-dependent and optimal at a rate of 300/s. Collagen types VII and VIII showed minor reactivity and supported platelet adhesion only between shear rates 100 to 1,000/s. Monoclonal antibody (MoAb) 176D7, directed against platelet membrane glycoprotein Ia (GPIa; very late antigen [VLA]-alpha 2 subunit), completely inhibited platelet adhesion to all collagens tested, under conditions of both stasis and flow. Platelet adhesion to collagen type III at shear rate 1,600/s was only inhibited for 85%. The concentration of antibody required for complete inhibition of platelet adhesion was dependent on the shear rate and the reactivity of the collagen. An MoAb directed against GPIIa (VLA-beta subunit) partially inhibited platelet adhesion to collagen. These results show that GPIa-IIa is a major and universal platelet receptor for eight unique types of collagen.     

Mental health intensive care: the nurses'experience and perceptions of a new unit

This paper describes a qualitative research study which explored the practices and views of nurses working on a new Mental Health Intensive Care Unit A review of the literature identified the main aspects of intensive care provision (1) physical security, (2) characteristics of the patient group, (3) staff-patient ratios, (4) therapeutic environment and (5) multi-agency involvement Twenty-one periods of participant observation helped form the questions for a semi structured in-depth tape recorded interview in which 11 out of a total of 16 trained nurses took part The information is categorized and the discussion is informed by observation of practice The nurses perceived the following as the main issues that the physical environment is inadequate for security, that the patient group appears to have the common characteristic of being unwanted in other clinical settings, that the staff-patient ratio is inadequate and that their vision of the nature of a therapeutic environment is vague     

Delayed iontophoretic ejection of substance P from glass micropipettes: correlation with time-course of neuronal excitation in vivo.

The microiontophoretic release of substance P (SP) and its carboxy-terminal octapeptide (SP8) was studied in vitro. At pH 5, SP and SP8 were released by a positive current. The rate of release was very low initially, increased with time, and then became constant. The duration of the initial period of low release was a function of the negative (retaining) current applied between release periods, and was unusually long even when relatively small retaining currents were used. In the presence of 17 mM sodium, the transport numbers of SP and SP8 were 0.016 and 0.0012, respectively. Addition of NaCl to the pipette produced a dramatic decrease in the transport number of SP (0.0008 in the presence of 170 mM NaCl).Substance P and SP8 were also applied in vivo in the vicinity of the noradrenaline-containing neurons of the rat locus coeruleus, using conventional five-barrel glass microelectrodes. Prior application of a 10nA retaining current for only 2 min delayed the response to iontophoresis of substance P by 30–40 sec. But when a very small retaining current (0.4 nA) was used between ejections, a very rapid excitatory response (within 5 sec) could be observed with as little as 5–15 nA of positive current. Following the delivery of SP or SP8 under such optimal conditions, recovery of neuronal firing rate was also rapid (10–30 sec).The low transport numbers and the long delay in the release of SP and of SP8 can be related to the physical and chemical characteristics of the molecules and the techniques of application. The low concentrations of these peptides present in the pipettes and their low diffusion constants are the main reasons for the differences of their iontophoretic behaviors from those of smaller neuroactive compounds.     

中药升麻的化学成分

从中药兴安升麻[Cimicifuga dahurica(Turcz.)Maxim.]的干燥根茎中分得五个化合物,其中四个为三萜木糖甙:升麻醇-3-O-β-D-吡喃木糖甙(23R,24S)(Ⅰ),25-O-乙酰升麻醇-3-O-β-D-吡喃木糖甙(23R,24S)(Ⅱ),12-羟基升麻醇-3-O-β-D-吡喃木糖甙(23R,24S)(Ⅲ),升麻醇-3-O-β-D-吡喃木糖基(3→1)-β-D-吡喃木糖甙(23R,24S)(Ⅳ),另一个为异阿魏酸(Ⅴ)。Ⅲ和Ⅳ为新化合物,通过光谱(IR,MS,¹H及¹³C NMR)解析确定了它们的结构,分别命名为升麻甙A(cimiside A)和升麻甙B(cimiside B)。