Antidepressant-like effect of a Ginkgo biloba extract (EGb761) in the mouse forced swimming test: role of oxidative stress

EGb761 is a well-defined mixture of active compounds extracted from Ginkgo biloba leaves. This extract is used clinically due to its neuroprotective effects, exerted probably via its potent antioxidant or free radical scavenger action. Previous studies suggest that oxidative stress, via free radical production, may play an important role in depression and animal models for depression-like behavior. Preclinical studies have suggested that antioxidants may have antidepressants properties. The aim of this study was to investigate the antidepressant-like of EGb761 due to its antioxidant role against oxidative stress induced in the forced swimming test, the most widely used preclinical model for assessing antidepressant-like behavior. Male BALB/c mice were pretreated with EGb761 (10 mg/kg, ip) daily for 17 days followed by the forced swimming test and spontaneous locomotor activity. Animals were sacrificed to evaluate lipid peroxidation, different antioxidant enzyme activities, serotonin and dopamine content in midbrain, hippocampus and prefrontal cortex. EGb761 significantly decreased the immobility time (39%) in the forced swimming test. This antidepressant-like effect of EGb761 was associated with a reduction in lipid peroxidation and superoxide radical production (indicated by a downregulation of Mn-superoxide dismutase activity), both of which are indicators of oxidative stress. The protective effect of EGb761 is not related to excitatory or inhibitory effects in locomotor activity, and was also associated with the modulation of serotonergic and dopaminergic neurotransmission. It is suggested that EGb761 produces an antidepressant-like effect, and that an antioxidant effect against oxidative stress may be partly responsible for its observed neuroprotective effects.     

Immunochromatographic assay for the detection of pseudojujubogenin glycosides

INTRODUCTION: Bacopa monnieri contains pseudojujubogenin glycosides as pharmacologically active compounds. In order to screen large numbers of plant samples for the presence of pseudojujubogenin glycosides, a rapid and simple assay system is required for application to small quantities of test materials. Immunoassays using monoclonal antibodies could be useful for the determination of small quantities of pseudojujubogenin glycosides in plant extracts. OBJECTIVE: The objective of this work was to develop a simple method for the detection of pseudojujubogenin glycosides by the immunochromatographic strip test using anti-bacopaside I monoclonal antibody. METHODOLOGY: The qualitative assay was based on a competitive immunoassay in which the detector reagent consisted of a colloidal gold particle coated with the respective anti-bacopaside I MAb. The capture reagent was a bacopaside I-human serum albumin conjugate immobilised onto a test strip membrane. RESULTS: The sample containing pseudojujubogenin glycosides and the detection reagent were incubated with the immobilised capture reagent. The glycosides in the sample competed in binding to the limited amount of antibodies in the detection reagent with the immobilised bacopaside I-HSA conjugates and, hence, positive samples showed no colour in the capture spot zone. The detection limit for the strip test was 125 ng/mL. CONCLUSION: The assay system was found to be useful as a rapid and simple screening method for the detection of pseudojujubogenin glycosides in plants.     

Cross‐sectional human immunodeficiency virus incidence estimation accounting for heterogeneity across communities

Accurate estimation of human immunodeficiency virus (HIV) incidence rates is crucial for the monitoring of HIV epidemics, the evaluation of prevention programs, and the design of prevention studies. Traditional cohort approaches to measure HIV incidence require repeatedly testing large cohorts of HIV‐uninfected individuals with an HIV diagnostic test (eg, enzyme‐linked immunosorbent assay) for long periods of time to identify new infections, which can be prohibitively costly, time‐consuming, and subject to loss to follow‐up. Cross‐sectional approaches based on the usual HIV diagnostic test and biomarkers of recent infection offer important advantages over standard cohort approaches, in terms of time, cost, and attrition. Cross‐sectional samples usually consist of individuals from different communities. However, small sample sizes limit the ability to estimate community‐specific incidence and existing methods typically ignore heterogeneity in incidence across communities. We propose a permutation test for the null hypothesis of no heterogeneity in incidence rates across communities, develop a random‐effects model to account for this heterogeneity and to estimate community‐specific incidence, and provide one way to estimate the coefficient of variation. We evaluate the performance of the proposed methods through simulation studies and apply them to the data from the National Institute of Mental Health Project ACCEPT, a phase 3 randomized controlled HIV prevention trial in Sub‐Saharan Africa, to estimate the overall and community‐specific HIV incidence rates.     

几种杀菌剂对黄瓜疫霉菌的毒力测定

采用菌丝生长速率法检测60%嘧菌酯悬浮剂、80%代森锰锌可湿性粉剂、75%百菌清可湿性粉剂、60%唑醚·代森联水分散粒剂、2%蛇床子素微乳剂、64%杀毒矾可湿性粉剂等6种杀菌剂对黄瓜疫霉菌的室内毒力。结果表明,唑醚·代森联和蛇床子素对黄瓜疫霉菌的毒力最高,EC50值分别为3.4143 mg·L-1和10.4641 mg·L-1。将两种原药混配后,表现出增效作用,在两者混配比为1∶2时增效最明显,EC50值为5.8178 mg·L-1。     

112株志贺菌菌群分布和药敏特点分析

目的研究本地区2001年至2005年志贺菌菌群分布及其药敏特点,以指导临床合理抗菌治疗。方法经大便培养筛选志贺菌,用生化和血清学方法鉴定菌群和血清型,采用K-B法检测病原菌耐药性。结果在112例细菌性痢疾患者中,男女比例相似,年龄分布以婴幼儿最高,临床表现不典型者较多,菌群分布以福氏志贺菌最多,F2b为优势血清型,对抗菌药物敏感性差异有显著性。结论近5年来本地区细菌性痢疾患者发病特点有年龄差异,菌群仍以福氏志贺菌为主,血清型以F2b为主,第3代头孢菌素是治疗细菌性痢疾最佳的抗菌药物。     

A Weight of Evidence Approach to the Aquatic Hazard Assessment of Bisphenoi A

Bisphenol A (BPA; 4,4-isopropylidene diphenol) is a chemical intermediate used primarily in the production of epoxy resins and polycarbonate products. BPA has been identified in surface waters and, hence, has been the subject of considerable research into its potential effects on aquatic organisms. Available literature on the aquatic toxicity of BPA was reviewed for quality against European Union TGD and Organization of Economic Cooperation and Development GLP principles. From this review, studies of suitable quality covering numerous ecologically relevant endpoints were identified to evaluate the survival, growth, and reproductive success of aquatic organisms exposed to BPA. Those studies yielded approximately 70 no observed effect concentrations (ranging from 16 to 3640 μg/L) and lowest observed effect concentrations (160 to 11,000 μg/L) that were considered in this weight of evidence assessment. Across all data, adverse effects on survival, growth, and reproduction occurred only at concentrations of 160 μg/L and above. Secondary biochemical (e.g., vitellogenin induction) and morphological (e.g., gonad histology) data provide insight into mechanisms of action, but do not correlate with apical endpoints related to survival, growth, and reproduction. Comparing the weight of the evidence of the aquatic toxicity data that showed chronic effects at 160 μg/L and higher with typical surface water concentrations in the range of 0.001 to 0.10 μg/ L, BPA is unlikely to cause adverse effects on aquatic populations or ecosystems.     

正交试验优化天麻超声波提取工艺的研究

为了优化天麻素的提取工艺,本研究采用超声法提取天麻素,以天麻素含量为指标,在单因素筛选基础上,采用正交试验优化提取工艺,选择料液比、提取次数和提取时间3个影响因素,每个因素3个水平进行正交试验。结果表明,最优提取工艺组合为:提取时间20min、料液比1∶15和提取次数2次;按照此工艺平行制备3批样品,天麻素的提取率为(0.339±0.13)%。     

Complete resistance to challenges with Hymenolepis nana cysticercoids derived from mouse, rat and beetle in mice

and 1986. Complete resistance to challenges with Hymenolepis nana cysticercoids derived from mouse, rat and beetle in mice. International Journal for Parasitology 16: 623–628. When BALB/c and dd strains of mice were given eggs of Hymenolepis nana, they all became completely resistant not only to challenge with mouse-derived cysticercoids but also to challenges with rat-derived and beetle-derived cysticercoids. Serum IgG antibodies at 47–60 days post egg inoculation reacted strongly with these three different host-derived cysticercoids when examined by IFA test, but IgA and IgM isotypes reacted very weakly. Antibodies of infected mouse sera (IgG, IgM and IgA were examined) reacted not only with the protoscolex (scolex of the excysted juvenile) but also with the outer cyst wall. By contrast, uninfected mouse sera and immune sera prepared seven days post cysticercoid inoculation did not react at all. Antigens of both cyst wall and protoscolex appeared to be of parasite origin and not of host origin, and appeared similar in parasites from the different host species.