艾叶的化学成分(Ⅱ)

目的对中药艾叶(Folium Artemisiae Argyi)的化学成分进行分离鉴定。方法采用反复硅胶柱色谱、Sephadex LH-20凝胶柱色谱、制备TLC、重结晶等方法进行分离纯化,通过理化常数测定和波谱分析等手段鉴定其化学结构。结果分离得到10个化合物,分别鉴定为isotanciloide(1)、伞形花内酯(umbelliferone,2)、瑞香素(daphnetin,3)、圣草酚(eriodictyol,4)、鼠李素(rhamnetin,5)、高车前素(hispidulin,6)、L-2-O-甲基-手-肌醇(L-2-O-methyl-chiro-inositol,7)、豆甾醇(stigmasterol,8)、胡萝卜苷(daucosterol,9)、4-甲氧基-3-羟基苯酚(4-methoxyl-3-hydroxyphenol,10)。结论其中,化合物10为新天然产物,化合物1-5、7为首次从艾叶中分离得到。     

板栗总苞中的抗糖尿病活性成分

目的分离鉴定板栗(Castanea mollissima Blume)总苞中抗糖尿病活性化合物。方法采用正-反相硅胶柱色谱和制备型HPLC进行分离,经理化常数测定、核磁共振技术分析等方法鉴定化合物的结构;对分离得到的单体化合物进行醛糖还原酶(aldose reductase,AR)抑制活性实验。结果从活性部位中分离得到9个化合物,分别为山柰酚(kaempferol,1)、没食子酸(gallic acid,2)、3,4-二羟基苯甲酸(3,4-dihydroxy-benzoic acid,3)、鞣花酸(ellagic acid,4)、苯甲基-6-O-β-D-吡喃葡萄糖苷(benzyl-O-β-D-glucopyranoside,5)、没食子酸正丁酯(n-butyl gallate,6)、2,4,6-三羟基苯甲酸(2,4,6-trihydroxy-benzoic acid,7)、没食子酸甲酯(methyl-gallate,8)、豆甾烷-4-烯-3,6-二酮(stig-mast-4-en-3,6-dione,9)。结论化合物5-7为首次从该属植物中分离得到,活性结果显示9个化合物均显示不同程度抑制活性,其中化合物4、5最为显著。     

白车轴草化学成分的分离与鉴定

目的为白车轴草(Trifolium repensL.)的药效物质基础提供依据。方法利用制备薄层、反复硅胶、Sephadex LH-20、开放ODS柱色谱等方法进行分离纯化,根据理化性质及波谱分析对分离得到的化合物进行结构鉴定。结果分离得到10个化合物,分别鉴定为伞形花内酯(umbelliferon,1)、芒柄花素(formononetin,2)、水杨酸(salicylic acid,3)、双白瑞香素(daphnoretin,4)、4′-methoxy-coumestrol(5)、trifoliol(6)、美迪紫檀素(medicarpin,7)、环阿尔廷-25-烯-3β,24ξ-二醇(cycloart-25-en-3β,24ξ-diol,8)、3β-hydroxy-7α-methoxy-24β-ethyl-cholest-5-ene(9)、soyasapogenol B(10)。结论化合物8、9为首次从车轴草属植物中分离得到,化合物1、3、4为首次从白车轴草中分离得到。     

菊黄上清含片的薄层色谱鉴别

目的建立菊黄上清含片的薄层鉴别方法。方法采用薄层色谱（TLC）法对菊黄上清含片中的羊耳菊、甘草、冰片3味药材进行定性鉴别。结果在薄层色谱中分别检出了羊耳菊、甘草、冰片的特征斑点,阴性对照无干扰。结论该方法简便可行、专属性强、重现性好,可用于菊黄上清含片的质量控制。     

Identification of a κ-opioid agonist as a potent and selective lead for drug development against human African trypanosomiasis

A resazurin-based cell viability assay was developed for phenotypic screening of the LOPAC 1280 ‘library of pharmacologically active compounds’ against bloodstream forms of Trypanosoma brucei in vitro identifying 33 compounds with EC₅₀ values <1 μM. Counter-screening vs. normal diploid human fibroblasts (MRC5 cells) was used to rank these hits for selectivity, with the most potent (<70 nM) and selective (>700-fold) compounds being suramin and pentamidine. These are well-known antitrypanosomal drugs which demonstrate the robustness of the resazurin cell viability assay. The most selective novel inhibitor was (+)-trans-(1R,2R)-U50,488 having an EC₅₀ value of 60 nM against T. brucei and 270-fold selectivity over human fibroblasts. Interestingly, (−)-U50,488, a known CNS-active κ-opioid receptor agonist and other structurally related compounds were >70-fold less active or inactive, as were several μ- and κ-opioid antagonists. Although (+)-U50,488 was well tolerated by the oral route and displayed good pharmaceutical properties, including high brain penetration, the compound was not curative in the mouse model of infection. Nonetheless, the divergence of antinociceptive and antitrypanosomal activity represents a promising start point for further exploratory chemistry. Bioinformatic studies did not reveal any obvious candidate opioid receptors and the target of this cytostatic compound is unknown. Among the other potent, but less selective screening hits were compound classes with activity against protein kinases, topoisomerases, tubulin, as well as DNA and energy metabolism.     

Value of non-clinical cardiac repolarization assays in supporting the discovery and development of safer medicines

Non-clinical QT-related assays aligned to the pharmaceutical drug discovery and development phases are used in several ways. During the early discovery phases, assays are used for hazard identification and wherever possible for hazard elimination. The data generated enable us to: (i) establish structure–activity relationships and thereby; (ii) influence the medicinal chemistry design and provide tools for effective decision making; and provide structure–activity data for in silico predictive databases; (iii) solve problems earlier; (iv) provide reassurance for compound or project to progress; and (v) refine strategies as scientific and technical knowledge grows. For compounds progressing into pre-clinical development, the ‘core battery’ QT-related data enable an integrated risk assessment to: (i) fulfil regulatory requirements; (ii) assess the safety and risk–benefit for compound progression to man; (iii) contribute to defining the starting dose during the phase I clinical trials; (iv) influence the design of the phase I clinical trials; (v) identify clinically relevant safety biomarkers; and (vi) contribute to the patient risk management plan. Once a compound progresses into clinical development, QT-related data can be applied in the context of risk management and risk mitigation. The data from ‘follow-up’ studies can be used to: (i) support regulatory approval; (ii) investigate discrepancies that may have emerged within and/or between non-clinical and clinical data; (iii) understand the mechanism of an undesirable pharmacodynamic effect; (iv) provide reassurance for progression into multiple dosing in humans and/or large-scale clinical trials; and (v) assess drug–drug interactions. Based on emerging data, the integrated risk assessment is then reviewed in this article, and the benefit–risk for compound progression was re-assessed. Project examples are provided to illustrate the impact of non-clinical data to support compound progression throughout the drug discovery and development phases, and regulatory approval.This article is part of a themed section on QT safety. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2010     

Mutations in the lipoma HMGIC fusion partner-like 5 (LHFPL5) gene cause autosomal recessive nonsyndromic hearing loss

In two large Turkish consanguineous families, a locus for autosomal recessive nonsyndromic hearing loss (ARNSHL) was mapped to chromosome 6p21.3 by genome-wide linkage analysis in an interval overlapping with the loci DFNB53 (COL11A2), DFNB66, and DFNB67. Fine mapping excluded DFNB53 and subsequently homozygous mutations were identified in the lipoma HMGIC fusion partner-like 5 (LHFPL5) gene, also named tetraspan membrane protein of hair cell stereocilia (TMHS) gene, which was recently shown to be mutated in the "hurry scurry" mouse and in two DFNB67-linked families from Pakistan. In one family, we found a homozygous one-base pair deletion, c.649delG (p.Glu216ArgfsX26) and in the other family we identified a homozygous transition c.494C>T (p.Thr165Met). Further screening of index patients from 96 Turkish ARNSHL families and 90 Dutch ARNSHL patients identified one additional Turkish family carrying the c.649delG mutation. Haplotype analysis revealed that the c.649delG mutation was located on a common haplotype in both families. Mutation screening of the LHFPL5 homologs LHFPL3 and LHFPL4 did not reveal any disease causing mutation. Our findings indicate that LHFPL5 is essential for normal function of the human cochlea.     

School health nurses and substance use among adolescents - towards individual identification and early intervention

Adolescents' health is today threatened by the use of alcohol and other psychoactive substances. It is therefore important to develop interventions related to substance use in school health care. The aim of this study was to examine the empowering or risk background factors related to substance use among adolescents, and the ability of school nurses (PHN) to identify these factors and to provide needed individual early intervention. The data were collected by semistructured questionnaires completed by 14- to 18-year-old adolescents (n = 326, response rate 79) and PHNs (n = 10) in 2004. The adolescent questionnaire consisted of items related to the respondents' background and Adolescents' Substance Use Measurement (ADSUME). Following individual consent, adolescents' ADSUME responses were sent to the PHNs for intervention. The PHNs assessed the adolescents' empowering background factors and intervention using the questionnaire, and 70% (n = 228) of their answers matched the adolescents' answers. The data were analysed with the SPSS software using the chi-squared test, Fisher's exact test, kappa coefficient and agreement percentages. Substance use among adolescents was associated with parental support, mother's education and smoking, the adolescents' knowledge about substances, peer support and hobbies. The PHNs' assessments regarding supportive background were not in agreement with the assessments of adolescents who were using hazardous substances. One-fifth of the adolescents received the brief intervention, although many of them might have needed extra support and follow-up on the basis of their ADSUME results. The research findings can be generalized only for alcohol use, because only 3% of the study informants used substances other than alcohol. Further research is warranted concerning PHNs' ability to identify hazardous substance use and to ensure preventive early intervention and requisite support among substance-using adolescents in order to improve evidence-based health promotion.     

Reliable detection of bilateral activation in human primary somatosensory cortex by unilateral median nerve stimulation

In non-human primates, a bilateral representation of unilaterally presented somatosensory information can be found at the lowest level of cortical processing as indicated by the presence of neurons with bilateral receptive fields in the hand region of primary somatosensory (SI) cortex. In humans, such bilateral activation of SI is considered controversial due to highly variable detection rates for the much weaker ipsilateral response across different studies (ranging from 3% to 100%). Second-order blind identification (SOBI) is a blind source separation algorithm that has been successfully used to isolate neuronal signals from functionally distinct brain regions, including the left- and right-SI. SOBI-aided extraction of left- and right-SI responses to median nerve stimulation from high-density EEG has been previously validated against the fMRI and MEG literature. Here, we applied SOBI to EEG data and examined whether relatively weaker ipsilateral activations could be reliably detected across subjects. In single subject analysis, statistically significant somatosensory evoked potentials (SEPs) in response to unilateral stimulation were detected from both SI contralateral to and SI ipsilateral to the side of stimulation. Furthermore, these ipsilateral responses were observed in both the left and right hemispheres of all 10 subjects studied. Together these results demonstrate that unilateral stimulation of the median nerve, whether applied to the left or right wrist, can activate both the left- and right-SI, raising the possibility that in humans, unilateral sensory input may be bilaterally represented at the lowest level of cortical processing.     

Performance enhancement for audio-visual speaker identification using dynamic facial muscle model

Science of human identification using physiological characteristics or biometry has been of great concern in security systems. However, robust multimodal identification systems based on audio-visual information has not been thoroughly investigated yet. Therefore, the aim of this work to propose a model-based feature extraction method which employs physiological characteristics of facial muscles producing lip movements. This approach adopts the intrinsic properties of muscles such as viscosity, elasticity, and mass which are extracted from the dynamic lip model. These parameters are exclusively dependent on the neuro-muscular properties of speaker; consequently, imitation of valid speakers could be reduced to a large extent. These parameters are applied to a hidden Markov model (HMM) audio-visual identification system. In this work, a combination of audio and video features has been employed by adopting a multistream pseudo-synchronized HMM training method. Noise robust audio features such as Mel-frequency cepstral coefficients (MFCC), spectral subtraction (SS), and relative spectra perceptual linear prediction (J-RASTA-PLP) have been used to evaluate the performance of the multimodal system once efficient audio feature extraction methods have been utilized. The superior performance of the proposed system is demonstrated on a large multispeaker database of continuously spoken digits, along with a sentence that is phonetically rich. To evaluate the robustness of algorithms, some experiments were performed on genetically identical twins. Furthermore, changes in speaker voice were simulated with drug inhalation tests. In 3 dB signal to noise ratio (SNR), the dynamic muscle model improved the identification rate of the audio-visual system from 91 to 98%. Results on identical twins revealed that there was an apparent improvement on the performance for the dynamic muscle model-based system, in which the identification rate of the audio-visual system was enhanced from 87 to 96%.