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101.
Carnivorous mollusks belonging to the genus Conus paralyze their prey by injecting a rich mixture of biologically active peptides. Conus regius is a vermivorous member of this genus that inhabits Brazilian tropical waters. Inter-, intra-species and individual variations of cone snail venom have been previously reported. In order to investigate intra-specific differences in C. regius venom, its feeding behavior and the correlation between these two factors, animals were pooled according to gender, size and season of collection, and their venom composition was compared by high performance liquid chromatography (HPLC). Both the whole venom and one specific peak were monitored by HPLC. Chromatographic profiles revealed no significant differences in their peak areas, indicating that the venom composition, based solely in the presence or absence of the major peaks, is stable regardless of season, gender and size. Therefore, analysis of one given toxin, eluting in one of the major peaks, is representative among the population. Moreover, this work presents the identification of one novel conotoxin (rg11a), which amino acid sequence was deduced by mass spectrometry.  相似文献   
102.
Traditional herbal medicines, popularly known as ‘jamu’ and ‘makjun’ in Malaysia and Indonesia, are consumed regularly to promote health. In consideration of their frequent and prolonged consumption, the natural occurrence of aflatoxins (AF) in these products was determined using immunoaffinity column clean-up and high-performance liquid chromatography with pre-column derivatization. The evaluated method, which entails dilution of sample extracts with Tween 20–phosphate buffered saline (1:9, v/v) and a chromatographic system using isocratic mobile phase composed of water–methanol–acetonitrile (70:20:10, v/v/v), was effective in separating AFB1, AFG1 and AFG2 from interference at their retention times. Results were confirmed using post-column derivatization with photochemical reactor. For 23 commercial samples analyzed, mean levels (incidence) of AFB1, AFB2 and AFG1 in positive samples were 0.26 (70%), 0.07 (61%) and 0.10 (30%) μg/kg, respectively; one sample was positive for AFG2 at a level of 0.03 (4%) μg/kg. In contrast to the high levels of AF in crude herbal drugs and medicinal plants reported previously by other researchers, the low contamination levels reported in this study may be attributed to the higher selectivity to AF of the method applied. Based on the AFB1 levels and the daily consumption of positive samples, a mean probable daily intake of 0.022 ng/kg body weight was calculated.  相似文献   
103.
一种新来源天然冰片与合成冰片的致突变性比较研究   总被引:4,自引:0,他引:4  
目的与方法采用鼠伤寒沙门氏菌回复突变试验(Ames试验),比较天然冰片与合成冰片的致突变作用.结果在标准平板掺入法试验中,天然冰片与合成冰片在0.4~250.0μg/皿范围内,无论有或无S9活化系统,对鼠伤寒沙门氏菌突变株(TA97、TA98、TA100、TA102)的回变菌落数均无明显影响,且回变菌落背景正常.结论新来源天然冰片与合成冰片在该实验室条件下均不具致突变效应.  相似文献   
104.
The Southern Pacific Rattlesnake (Crotalus helleri) is found in southwestern California (USA), southward through north Baja California (MX) into the northern part of southern Baja California (MX). In this study, the venoms from two Southern Pacific Rattlesnakes were characterized. The two venoms were different in color, concentration, and enzyme activities. Two commercial antivenoms neutralized both C. helleri venoms differently. Antivipmyn (Fab2H) and CroFab (FabO) neutralized both venoms but had different ED50. Four times more Fab2H antivenom was required to neutralize the C. helleri venom No. 011-084-009 than the venom from the snake No. 010-367-284. The hemorrhagic activity of two C. helleri venoms were neutralized differently by endothermic animal sera having a natural resistance to hemorrhagic activity of snake venoms. Opossums and Mexican ground squirrel sera did not neutralize the hemorrhagic activity of the venom No. 010-367-284. The sera of gray woodrats and hispid cotton rats neutralized all hemorrhagins in both C. helleri venoms. This is the first reported case in which opossum serum has not neutralized hemorrhagic activity of pit viper venom. Differences in the compositions of C. helleri venoms and their ability to be neutralized may help explain why snakebites are a difficult medical problem to treat and why effective polyvalent antivenoms are difficult to produce.  相似文献   
105.
目的 调查了解湖南省天然矿泉水饮用人群的健康状况。方法选择长期饮用天然矿泉水人群为观察组,条件相近不饮用矿泉水人群为对照组,对比两组间健康指标的差异。结果 长期饮用天然矿泉水人群平均期望寿命(e^9)为72.04岁,比不饮用天然矿泉水的对照组人群e^0高出2.99岁,平均死亡年龄要高4.15岁,总患病率要低14.3%,人均医疗费用开支要少28.6%;男女小学生生长发育:男生身高高3.06cm,女生身高高4.26cm;男生体重重2.51kg,女生体重重3.40kg;男生胸围大1.62cm,女生胸围大1.81cm。结论长期饮用天然矿泉水人群的健康状况要优于条件相近不饮用矿泉水人群。  相似文献   
106.
目的 对国家自然科学基金委员会立项资助的儿科研究课题进行回顾整理与数据分析,以了解学科重点支持领域和研究方向、热点的变化。方法 以中国国家自然科学基金数据库为基础,对2009~2018年儿科领域研究课题进行筛选,并对资助力度和研究方向变化进行分析。结果 2009~2018年国家自然科学基金委员会共资助1 017项儿科领域课题,其中面上项目485项(47.69%),青年基金426项(41.89%),地区项目73项(7.18%),重点项目16项(1.57%),优青项目6项(0.59%),海外项目7项(0.69%),其他项目4项(0.39%)。资助经费总额从2009年的842万元增加至2018年的6 625万元,增幅近7倍之多。以生殖系统/围产期医学/新生儿、神经系统和精神疾病、循环系统为一级学科代码申请立项的课题获资助力度最大。结论 近10年来国家自然科学基金委员会对儿科研究的资助力度持续增加,以面上项目和青年基金为主;研究获资助项目申请方向以新生儿、神经系统和精神、循环系统疾病为主。  相似文献   
107.
Production cross-sections of the natNi(p,x)60,61Cu, 56,57Ni, 55,56,57,58Co nuclear reactions were measured in five experiments up to 65 MeV by using a stacked foil activation technique. The results were compared with the available literature values, predictions of the nuclear reaction model codes ALICE-IPPE, TALYS-1.4, and extracted data from the TENDL-2012 library. Spline fits were made on the basis of selected data, from which physical yields were calculated and compared with the literature values. The applicability of the natNi(p,x)57Ni, 57Co reactions for thin layer activation (TLA) was investigated. The production rate for 55Co was compared for proton and deuteron induced reactions on Ni.  相似文献   
108.
Examining the processes of natural selection, described by Darwin in The Origin of Species, casts light on our own species’ fundamental needs and on the far greater role that early childhood educators can play in their fulfillment. The second section of this paper analyzes how our fundamental needs emerge in a sequence underpinned by the processes of natural selection (goodness‐of‐fit, variation and replication), are thus developmental in a new sense and are fulfilled only as organisms interact with their immediate environment. The subsequent section presents a model of how, in accordance with natural selection, adults can practise collaborative behaviors that facilitate this developmental sequence throughout life. The fourth section shows how early childhood educators who practise this model in interaction with their immediate environment (which includes parents) help to fulfill the fundamental needs and increase the internal resources of all participants—themselves, parents and children. Substantiating evidence comes from the author’s studies.  相似文献   
109.
110.
Effect of Punarnavine on the cell-mediated immune (CMI) response in metastatic condition was studied using C57BL/6 mice model. Administration of Punarnavine enhanced Natural Killer (NK) cell activity, antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent complement mediated cytotoxicity (ACC) and the activity was observed in treated group much earlier compared to the metastatic tumor-bearing control. Production of cytokines such as IL-2 and IFN-γ were significantly enhanced by the administration of Punarnavine compared to the untreated metastatic tumor-bearing control. Peaks of pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α were significantly lowered by Punarnavine administration compared to metastatic control. The level and expression of TIMP-1 was also enhanced by the administration of Punarnavine compared to metastatic tumor bearing control. These results indicate Punarnavine could enhance the immune response against metastatic progression of B16F-10 melanoma cells in mice.  相似文献   
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