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1.
Lymphatic filariasis caused mainly by infection fromWuchereria bancrofti andBrugia malayi remains as the major cause of clinical morbidity in tropical and subtropical countries. Development of vaccine against filarial infection can act as additional measure to the existing therapeutic and vector control methods in the control of this disease. The main hurdles in the development of anti-filarial vaccine are the strict primate specificity ofWuchereria bancrofti, the paucity of parasite material, the diversity of clinical manifestations and their associated complex immune responses, lack of clear understanding on host-parasite interactions and the mechanisms involved in protective immunity. However in the past few years, the information generated in immuno-epidemiological studies, correlated with observations in experimental animals suggests that a filarial vaccine is feasible. Initially live irradiated infective larvae have been successfully used to induce high level of protective immunity in several animal models. Applying diverse strategies, variety of purified or recombinant filarial antigens have been explored for their ability to induce protection in different host-parasite systems. Some of these targeted filarial antigens induced high level of resistance in experimental animals against challenge infections. More focussed studies on thorough characterization of parasitological and immunological changes associated with resistance induced by such candidate protective antigens and on delivery mechanisms and safety aspects will be crucial in their selection for possible use in humans.  相似文献   

2.
A rational approach for developing effective filaricides awaits greater knowledge on the biochemical pathways operating in filarial parasites. For example, metabolic pathways or key enzymes that are so pivotal to the parasite that their interruption or inhibition causes spontaneous death, could be exploited to develop effective chemotherapeutic agents. Similarly, developing a safe and nontoxic filaricidal will require precise understanding of whether or not the potential molecular target in the parasite is unique or at least different enough from the host system. Recently, we identified a novel transglutaminase enzyme (EC2.3.2.13; TGase) in filarial parasites that plays an important role during their normal growth and development. Based on these principles, TGase may serve as a new target for the development of effective chemotherapeutic agent and vaccine for controlling and preventing the infections caused by these parasites.  相似文献   

3.
Rats fed with hypercholesterolemic diet showed a significant increase in serum total—cholesterol, liver homogenate total-cholesterol, HDL-cholesterol and changed LDL-cholesterol, and HDL/LDL ratio in comparison to control. Flaxseedchutney (FC) supplemented diet (15%, w/w) was found to be more effective in restoring lipid profile changes in rats fed with cholesterol, (1.0%). The activities of serum marker enzymes glutamate oxaloacetate transminase (GOT), glutamate pyruvate transaminase (GPT) and alkaline phosphatase (ALP) were elevated significantly in carbon tetrachloride induced rats. Administration of flaxseedchutney (15%, w/w) resulted in depletion of serum marker enzymes and exhibited recoupment thus showing significant hepatoprotective effect. It was observed that flaxseedchutney supplemented diet could lower the serum cholesterol and as a potential source of antioxidants it could exert protection against hepatotoxic damage induced by carbon tetrachloride (CCl4) in rats.  相似文献   

4.
Lymphatic filariasis continues to be the major cause of clinical morbidity in India and other developing tropical countries. One of the major lacunae in the effective management of clinical filarial cases is the non-availability of a suitable diagnostic test for confirming filaria aetiology in acute, chronic and occult clinical cases where microfilariae (mf) are not usually seen in peripheral circulation. Studies in our laboratory have shown the usefulness of filarial antibody and antigen assays using microfilarial excretory-secretory (mf ES) antigen in detecting microfilaraemic, acute and chronic filarial cases and in confirming filarial aetiology in occult infections. Diethylcarbamazine citrate (DEC) is the drug of choice for lymphatic filariasis. Different regimens of DEC have been explored in the treatment of microfilaraemic cases. Immunomonitoring has shown that the seroconversion of antigen and antibody positivity was found to be very helpful in determining appropriate period of DEC treatment for clinical relief and cure in clinical filarial patients and further they did not have recurrence in most of the cases. Optimal DEC (6mg/kg body wt/day for 21 days each month for 3–12 months) therapy was found to be very effective in acute and atypical clinical manifestations such as asthmatic bronchitis, pulmonary eosinophilia, monoarthritis, recurrent upper respiratory tract infections (URI), pneumonia (super imposed infections) in children and minimal hydrocele, epididymoorchitis, lymphangitis, lymphadenitis, acute abdomen, central serous retinopathy, tenosynovitis, pain and swelling in limbs and joints in adults living in filaria endemic areas.  相似文献   

5.
Dietary spice components ofCurcuma longa andAbroma augusta have been screened for their protective effect against reactive oxygen species induced lipid peroxidation. They have been found to be efficient antioxidant when administered in combination. The purpose of the study was to investigate the effect of oral administration (300mg/Kg) of the aqueous extract of turmeric whose active ingredient isCurcumin andAbromine powder as a hypoglycemic agent mixed with diet. The effect of this aqueous extract on blood glucose, lipid peroxidation (LPO) and the antioxidant defense system in rat tissues like liver, lung, kidney and brain was studied for 8 weeks in streptozotocin induced diabetic rats. The administration of an aqueous extract of turmeric and abromine powder resulted in a significant reduction in blood glucose and an increase in total haemoglobin. The aqueous extract also resulted in decreased free radical formation in the tissues studied. The decrease in thiobarbituric acid reactive substances (TBARS) and increase in reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) clearly showed the antioxidant property of the mixture. It is suggested that these changes initially counteract the oxidative stress in diabetes however, a gradual decrease in the antioxidative process may be one of the factors which results in chronic diabetes. These results indicate that the mixture of the two plants have shown antidiabetic activity and also reduced oxidative stress in diabetes. A combination ofAbroma augusta and Curcuma longa also restored the other general parameters in diabetic animals. The results were statistically analyzed and indicated that combination of herbal extracts showed better efficacy as compared to individual herbal plant extracts used.  相似文献   

6.
Sera samples of 7 microscopic haematuria cases collected before and after treatment with Diethylcarbamazine citrate, (DEC), 9 microfilaraemic cases and 19 endemic normal individuals were analysed for filarial antigen and IgG antibody levels. Filarial antigen was detected in 5 of the 7 microscopic haematuria cases, of which 3 turned negative for antigen after treatment with DEC. While none of the 7 haematuria cases were positive for filarial IgG antibodies, before the DEC treatment, all of them turned positive after DEC treatment. The sensitivity and specificity values(to detect mf +ve cases) were 89% and 90% respectively for the detection of filarial antigen and 78% and 95% respectively for the detection of filarial IgG antibodies.  相似文献   

7.
Brugia malayi microfilarial excretory-secretory (mf ES) antigens obtained byin vitro maintenance of mf are important tools in the immunodiagnosis of bancroftian filariasis. To increase the yield of mf ES products, the effect of nutritional supplements on the culture medium (RPMI 1640) and the maintenance temperature were studied. Supplementation of RPMI 1640 medium with organic acids and sugars of Grace's insect culture medium forin vitro maintenance of 10 lakhs of mf in 40 ml medium increased the yield of mf ES antigen from 152 μg to 364 μg of mean protein, content and the mean antigen titre from 200 to 400. Supplementation with phenyl methyl sulphonyl fluoride (PMSF) and shift in the culture temperature resulted in a further increase in the yield of mf ES antigen to 502 μg of mean total protein with an antigen titre of 800. The modification resulted in a net increase of 3 fold in the protein content and 4 fold in the antigen titre of ES products. The above modifications in thein vitro maintenance of mf did not affect the diagnostic quality of mf ES antigen, which gave a sensitivity and specificity of 80% and 90% respectively in detection of filarial IgG antibodies inWuchereria bancrofti infected cases.  相似文献   

8.
本文首次结合条件价值支付意愿和行为经济学的心理参照点理论考察了农民灌溉水价的心理决策机理。研究发现:农民的心理参照点水价是影响其灌溉水费支付行为的重要微观心理因子。通过对四川省21县区567份样本数据分析发现,样本区农民(92.06%)的心理参照点水价等于零或小于实际水价是水费政策执行难的直接微观心理原因;近期政府"既免又补"的农业政策影响和降低了农民的心理参照点水价,导致了税费改革后水费执行难度加大;同时,受教育时间、性别、去年家庭开支、去年水稻收入、水价制订是否公平等因素也会不同程度地影响农民的心理参照点水价,这些因素的变化也会影响农民心理参照点水价的水平。本文的政策启示主要包括政府政策应考虑农民心理决策机理,政策应注重农民权利与义务并重,着力提高农民的心理参照点水价等。文后还指出了值得进一步研究的不足与启示。  相似文献   

9.
In Ayurvedic medicine,Withania somnifera (Ashwagandha) is well known for its anti-stress activity. A passive rat experimental model, where the animals are subjected to multiple stress of cold, hypoxia, restraint (C-H-R) has been developed to evaluate adaptogenic properties of various fractions of W. somnifera root extracts. We have carried out extraction of roots of W. somnifera with water and further isolated one of the active constituents called compound X and also tested its anti-stress activity in C-H-R model. The effect of administration of W. somnifera water suspension (360 mg/Kg bw) and compound X (20mg/Kg bw) on the fall and recovery of colonic temperature was noted. There was an increase of ≈38% and ≈54% in the time taken to attain Trec 23°C by rats given a single dose of fresh aqueous suspension and biologically active constituent (Compound X) respectively, where as decrease in the recovery time to attain Trec 37°C is ≈13% and ≈33% respectively, as compared to control group. It is clear that rats treated with the fresh aqueous suspension and compound X ofWithania somnifera, could withstand the multiple stress of C-H-R better than control group.  相似文献   

10.
In vitro released antigens by living parasites or bacteria underin vitro maintenance or short term culture showing specific humoral immune response have been explored in development of immunodiagnostics for infectious diseases such as filariasis and tuberculosis in our laboratory. ELISA usingB. malayi mf ES antigen has been explored for detecting IgG antibody by Indirect ELISA and antigen by Inhibition ELISA and in immunomonitoring of carriers as well as clinical filarial cases. A ten year follow up of mf carriers with DEC therapy showed disapperance of antigen and antibody followed by reappearance in few cases in an endemic area. None of the cases followed developed clinical symptoms suggesting the need for long term monitoring and treatment of microfilaraemic carriers. Further immunomonitoring was found to be useful in confirming filaria aetiology in the absence of microfilaremia and determining appropriate period of treatment of acute, early clinical and occult filarial infections for clinical relief and cure.Indirect Stick Penicillinase ELISA system using Mtb EST-6 antigen for detecting tuberculous IgG antibody and a Sandwich Penicillinase ELISA system using affinity purified antibody for detecting circulating antigen were explored in tuberculosis. A combination of both the assay systems with a sensitivity of 70% and specificity of 98% was found to be promising in the precise diagnosis of pulmonary tuberculosis. Further antigen detection was found to be useful in bone and joint tuberculosis.  相似文献   

11.
Background: Imbalance in cholesterol homeostasis may lead to gallstone disease. Apolipoprotein B is sole component of low-density lipoprotein and plays an important role in cholesterol metabolism. The present study was carried out to explore the association of APOB 3′ VNTR, exon 26 XbaI and signal peptide insertion/ deletion polymorphisms with gallstone disease. 214 ultrasonographically proven gallstone patients and 322 healthy, age and sex matched controls were taken for the study. Genotyping was done using PCR followed by polyacrylamide gel electrophoresis for VNTR and insertion/ deletion analysis. For APOB XbaI polymorphism PCR product was digested with XbaI restriction enzyme, followed by agarose gel electrophoresis. All statistical analyses were done using SPSS v11.5. Higher repeat alleles of APOB 3′ VNTR polymorphism were more frequent in gallstone patients than in controls. Alleles with more than 57 repeats were present only in patient group. Long (L) alleles with repeat higher than 49, were significantly higher (P=0.000; OR=3.705, 95% CI 2.577–5.326) and medium (M) alleles were lower (P=0.000; OR=0.406, 95% CI 0.304–0.542) in patients than in controls. To nullify the effect of gender, data was further stratified into male and female population. APOB 3′ VNTR, L alleles were imposing risk and M alleles were protective in both male and female population. APOB XbaI and insertion/deletion polymorphisms were not found to be associated with the gallstone disease. Longer alleles of APOB 3′ VNTR occur more frequently in gallstone patients, and may be an important risk factor for the development of gallstone disease. APOB XbaI and signal peptide insertion/deletion polymorphisms may not be contributing to the risk for gallstone disease.  相似文献   

12.
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13.
基于MODIS数据的泰国林地资源提取   总被引：1，自引：1，他引：0  
吕婷婷  孙晓宇  于伯华 《资源科学》2008,30(7):1076-1083
遥感技术的发展为我们对世界资源的研究提供了新的手段,克服了世界资源研究过程中数据缺乏的困难。泰国曾经是林地资源丰富的国家,尤其是热带林地资源,但是近几十年来林地面积在不断减少,带来了一系列生态问题。选用MOD09Q1的1、2波段,MOD09A1的第6波段以及MOD11A2数据产品提取了泰国林地分布情况。由于泰国地处热带地区云雾噪音为林地的提取造成了很大的不确定性,为了有效去除云雾噪音影响,结合NDVI、NDSI、LST多参数在林地提取中的优势对泰国林地进行提取。采用泰国2003年统计年鉴提供的分省林地面积以及2003年p131r47和p131r48共2景ETM影像进行了精度验证。结果表明,利用多参数综合分类方法对林地提取精度较高,通过与2003年统计年鉴数据进行回归分析发现二者存在明显的线性关系,决定系数达到0.9264。  相似文献   

14.
[目的]为丰富期刊学术影响力评价指标体系,提出了一种新的期刊学术影响力评价指标-f(x)指数。[方法]以《中国科技期刊引证报告》2012年期刊目录中的34种图书情报学期刊为例,通过CNKI获取各期刊2012年的载文量、篇被引频次,利用excel、c++计算相应评价指标的得分,并根据f(x)指数的得分对期刊进行排名。[结果]与当年遴选出的CSSCI核心期刊相比,评价结果准确率达94.12%;对各指标进行相关分析,发现f(x)指数与包括影响因子在内的多种期刊评价指标存在较强的正相关。[结论]f(x)指数利用对数函数的性质,考虑了期刊的载文量、总被引、篇均被引等因素,考虑了低被引和高被引论文的差异性,可作为期刊学术影响力评价的指标。  相似文献   

15.
The hypoglycemic effect of the aqueous extract ofAbroma augusta (Family: Steculiceae) was studied in normal as well as alloxan diabetic rats. Treatement of diabetic rats with 4 ml (4gm dry weight) of agueous extract ofA. augusta for 16 weeks resulted in gradual but significant fall in fasting blood glucose and improvement in glucose tolerance. Serum total and LDL cholesterol and triacylglycerol which increased in diabetic rats showed improvement. These results show that the water extract ofA. augusta has both hypoglycemic and hypocholesterolemic effects.  相似文献   

16.
Curcuma longa commonly known as tumeric is traditionally used as a spice in Indian food. A wide range of biological activities e.g. anticancer, antimicrobial, antiinflammatory and free radical scavenging activity of the plant suggests a logical basis for its traditional use in foodstuff. Various phytothreapeutic uses ofCurcuma longa have been reviewed.  相似文献   

17.
Many operational IR indexes are non-normalized, i.e. no lemmatization or stemming techniques, etc. have been employed in indexing. This poses a challenge for dictionary-based cross-language retrieval (CLIR), because translations are mostly lemmas. In this study, we face the challenge of dictionary-based CLIR in a non-normalized index. We test two optional approaches: FCG (Frequent Case Generation) and s-gramming. The idea of FCG is to automatically generate the most frequent inflected forms for a given lemma. FCG has been tested in monolingual retrieval and has been shown to be a good method for inflected retrieval, especially for highly inflected languages. S-gramming is an approximate string matching technique (an extension of n-gramming). The language pairs in our tests were English–Finnish, English–Swedish, Swedish–Finnish and Finnish–Swedish. Both our approaches performed quite well, but the results varied depending on the language pair. S-gramming and FCG performed quite equally in all the other language pairs except Finnish–Swedish, where s-gramming outperformed FCG.  相似文献   

18.
【目的】通过对《中国化学快报》办刊经验的总结和遇到问题的剖析,探讨中国英文科技期刊的发展之路。【方法】对《中国化学快报》近年的发展历程进行研究,从中发现中国英文科技期刊发展过程的共性问题,并进行提炼总结。【结果】中国英文科技期刊的生存环境已得到较大改善,但在评价体系等大政策的影响下,优质稿件匮乏、人才流失严重、国际显示度低等共性问题依然存在。【结论】在大政策暂时无法突破的现状下,加强内功修炼,寻找适合自身发展的办刊道路,尽快提高中国英文科技期刊的办刊水平。  相似文献   

19.
BackgroundAlthough bioactive metabolites capable of causing oxidative photo-necrosis in plant tissues have been identified in fungi, little is known about this type of mechanism in bacteria. These metabolites act as photosensitizers that generate reactive oxygen species (ROS) capable of causing damage to cells. In addition, these metabolites can pass into an energetically excited state when they receive some luminous stimulus, a condition in which they interact with other molecules present in the environment, such as molecular oxygen (O2), also known as triplet oxygen (3O2), generating ROS.ResultsThe suspension of the bacterial culture of Pseudomonas cedrina was shown to produce foliar necrosis in papaya leaves (Carica papaya L.) only in the presence of sunlight, which is evidence of photosensitizing mechanisms that generate singlet oxygen (1O2). From the chemical study of extracts obtained from this bacteria, 3-(4-(2-carboxipropyl) phenyl) but-2-enoic acid (1) was isolated. This compound, in the presence of light and triplet oxygen (3O2), was able to oxidize ergosterol to its peroxide, since it acted as a photosensitizer producing 1O2, with which it was corroborated that a photosensitization reaction occurs, mechanism by which this bacterium could prove to cause oxidative foliar photo-necrosis.ConclusionsP. cedrina was able to induce oxidative foliar photo-necrosis because of its potential ability to produce photosensitizing metabolites that generate singlet oxygen in the plants it colonizes. Based on the above, it can be proposed that some bacteria can cause oxidative foliar photo-necrosis as an important mechanism in the pathogenesis of host species.How to cite: Mendoza G, Sánchez-Tafolla L, Trigos A. Oxidative foliar photo-necrosis produced by the bacteria Pseudomonas cedrina. Electron J Biotechnol 2020;44. https://doi.org/10.1016/j.ejbt.2020.01.007  相似文献   

20.
Researchers in indexing and retrieval systems have been advocating the inclusion of more contextual information to improve results. The proliferation of full-text databases and advances in computer storage capacity have made it possible to carry out text analysis by means of linguistic and extra-linguistic knowledge. Since the mid 80s, research has tended to pay more attention to context, giving discourse analysis a more central role. The research presented in this paper aims to check whether discourse variables have an impact on modern information retrieval and classification algorithms. In order to evaluate this hypothesis, a functional framework for information analysis in an automated environment has been proposed, where the n-grams (filtering) and the k-means and Chen’s classification algorithms have been tested against sub-collections of documents based on the following discourse variables: “Genre”, “Register”, “Domain terminology”, and “Document structure”. The results obtained with the algorithms for the different sub-collections were compared to the MeSH information structure. These demonstrate that n-grams does not appear to have a clear dependence on discourse variables, though the k-means classification algorithm does, but only on domain terminology and document structure, and finally Chen’s algorithm has a clear dependence on all of the discourse variables. This information could be used to design better classification algorithms, where discourse variables should be taken into account. Other minor conclusions drawn from these results are also presented.  相似文献   

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