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Search Results: 1 - 10 of 9278 matches for " PCR "
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POLYMERASE CHAIN REACTION (PCR)
Abdul Haque
The Professional Medical Journal , 1997,
Abstract:
Direct real-time PCR examination for Mycobacterium tuberculosis in respiratory samples can be cost effective  [PDF]
Bryan Joseph Renton, Patricia Denise Morrell, Richard Peter Davidson Cooke, Peter David Owen Davies
Health (Health) , 2009, DOI: 10.4236/health.2009.12011
Abstract: Aim: To assess whether the use of direct real- time polymerase chain reaction (PCR) on smear-positive sputa can be cost-effective, by speciating mycobacteria earlier than current methods and thereby preventing unnecessary screening tests as part of the contact tracing process. Methods: A retrospective study of all patients with smear-positive sputa in a Liverpool teach-ing hospital between 2004 and 2007. All the PCRs performed on these patients were re-viewed and compared them with their myco-bacterial culture results. Unit costs for PCR, chest X-ray (CXR), tuberculin skin test (TST), interferon-gamma (IFN-γ) and medical/nursing time were conservatively estimated at £50, £11, £10, £40 and £30 respectively. The total PCR costs were compared with the costs of unnec-essary follow up of patients, negative for My-cobacterium tuberculosis (MTB) by PCR, sub-sequently confirmed to be MTB culture nega-tive. Results: 203 smear-positive patients under-went direct PCR testing. 126 (62%) patients grew Mycobacterium tuberculosis (MTB), 74 (37%) had environmental mycobacterial infection (EMI) and 3 (1%) were culture negative. Of the 126 patients’ culture positive MTB patients, 123 were PCR positive and 3 PCR negative. Of the 77 pa-tients that were culture negative for MTB, 75 were PCR negative and 2 PCR positive The sensitivity, specificity, positive and negative predictive values for direct PCR versus MTB culture were 98%, 96%, 98% and 97% respec-tively. Total costs of all PCRs performed amounted to £10,150. The cost of contact pro-cedures for PCR-negative and MTB culture- negative index cases was estimated at £19,650. This equated to a total saving of £9,500 in contact tracing costs. Conclusions: Direct PCR examination testing of smear-positive patients can be cost-effective in areas where there is a high incidence of EMI.
Effect of a novel compound from Lycopodium obscurum L. on osteogenic activity of osteoblasts in vitro  [PDF]
Chaoyuan Wang, Ruiyun Wu, Guangzhong Yang, Keith A. Blackwood, Thor Friis, Dietmar W. Hutmacher, Maria Ann Woodruff
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.51014
Abstract: We investigated the potential of an extract of Lycopodium obscurum L.; stigmastane-3-oxo- 21-oic acid (SA), to enhance osteogensis of mouse osteoblastic MC3T3-E1 cells. SA at a concentration of 16 μM was found to have no significant effect upon the viability of the cells, thus concentrations of 8 μM and 16 μM of SA were used in all further experiments. Both concentrations of SA had an inhibitory affect upon alkaline phosphatase activity (ALP) after 8 days incubation, however, after 16 days activity was restored to control levels. However Alizarin red S staining showed increased levels of mineralization for both concentrations after 16 days culture. Real time PCR showed inhibition of genes Runx2 and Osterix genes responsible for the up-regulation of ALP. However early time point (8 days) up-regulation of bone matrix mineralization genes OPN and OCN, and late time point (16 days) up-regulation of both Jun-D and Fra-2 mRNA expression was significantly enhanced. These results suggest a potential mechanism of SA in enhancing bone fracture healing is through the up-regulating bone matrix mineralization.
Comparative Study of Different Methods for Analyzing Denitrifying Bacteria in Fresh Water Ecosystems  [PDF]
Kristina Rathsack, J?rg B?llmann, Marion Martienssen
Journal of Water Resource and Protection (JWARP) , 2014, DOI: 10.4236/jwarp.2014.66059
Abstract:

Bacteria capable of denitrification play a significant role in the nitrogen cycle of freshwater ecosystems. By metabolizing nitrogen compounds they e.g. counteract the eutrophication of natural waters. To get detailed insights into the in situ turnover rates of nitrogen a reliable tool of quantification for active microorganisms is essential. In the present investigation, quantification capabilities of a molecular tool (Polymerase Chain Reaction—PCR) and a cultivation based tool (Most probable number—MPN) were investigated and compared. The total bacterial concentration yielded by the molecular PCR approach was up to 6-fold higher compared to the results of the MPN approach. However, the portion of culturable denitrifying bacteria compared to the number of specific gene copies (nirS) was much lower. Depending on the environmental conditions, the difference between the PCR and the MPN approach was up to three orders of magnitude. From lab scale experiments with a pure P. aeroginosa strain it can be concludes, that these differences are not the result of inappropriate culture conditions but rather reflect the portion of so called viable but not culturable bacteria (VBNC). Low nitrate concentrations as found in many fresh water ecosystems induced a significant increase in the portion of non culturable denitrifying bacteria. Referred to the investigation of dynamic populations, the number of metabolic active bacteria is represented by the MPN rather than by the PCR approach.

聚合酶链式反应(PCR)技术研究新进展
曹雪雁,张晓东,樊春海,胡钧
自然科学进展 , 2007,
Abstract: 聚合酶链式反应(PCR)在生命科学的研究领域已经得到了广泛的应用.文中对PCR技术的一些最新进展进行了简要的综述,其中包括定量PCR、纳米PCR、PCR芯片、原位PCR和免疫PCR的原理和应用.
Molecular Characterization of Echinococcus granulosus in South of Iran  [PDF]
Saeid Hosseinzadeh, Mehdi Fazeli, Arsalan Hosseini, Seyed Shahram Shekarforoush
Open Journal of Veterinary Medicine (OJVM) , 2012, DOI: 10.4236/ojvm.2012.24032
Abstract: The focus of present study was to determine the epidemiological and molecular aspects of different strains of cystic echinococcosis in Fars province, Iran. Liver and lung samples from 410 sheep, 206 goats and 315 cattle were collected. In cattle, the infestation rate was 18.1% (57/315), with 11.1% hepatic cysts and 7.0% pulmonary cysts. Out of all identified cysts, 31.4% of the hepatic and 31.8% of the pulmonary cysts were found fertile. Incidence rate of hydatid cyst infection in sheep was 15.5% (64/410) with 11.9% hepatic cysts and 3.6% pulmonary cysts, of which 24.5% and 20% of hepatic and pulmonary cysts were respectively identified as fertile. The infestation rate was 16.0% (33/206) in goat, in which 10.2% and 5.8% cysts were collected from liver and lung, correspondingly. The prevalence of fertile hepatic and pulmonary cysts was recorded as 23.8% and 16.7%, respectively. Genotyping the cystic materials using PCR showed that the most prominent strains responsible for cystic echinococcosis in the Fars province are G1 and G6/7, while no evidence of E. multilocularis was recorded. This information may give us some clues to find out more about strains distribution in different regions in Iran, which may finally use to find tools in the eradication program of the disease, here and elsewhere.
Clinical Presentations of HHV-6 Infection in Infants and Children in Kuwait: A Retrospective Study  [PDF]
Nada Madi, Haya Al-Tawalah, Widad Al-Nakib
Advances in Microbiology (AiM) , 2014, DOI: 10.4236/aim.2014.415119
Abstract: Clinical manifestations of human herpesvirus 6 (HHV-6) have not been clearly defined, and the role of HHV-6 in human disease among infants and children in Kuwait remains to be fully elucidated. A retrospective study covering the period between 2008 and 2014 was conducted on infants and children aged from 1 month to 5 years. Blood and CSF samples from infants and children who presented with symptoms suggestive HHV-6 infection were subjected to PCR test for HHV-6. Results showed that 9.3% (n = 42) of infants and children were positive for HHV-6. Fever was the most noticeable symptoms, presenting in 50% (n = 21) of the patients. Also, neutropenia was highly associated with HHV-6 infection, where it presented in 35.8% (n = 15) of infants and children. Our results provided important information about the clinical outcome of HHV-6 infection among infants and children in Kuwait.
Comparative Evaluation of Traditional Susceptibility Testing for MRSA with the PCR Approach  [PDF]
Tim Sandle, Ilya Azizov, Dmitriy Babenko, Antonella Chesca, Alena Lavrinenko
Advances in Microbiology (AiM) , 2014, DOI: 10.4236/aim.2014.416130
Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a multi-drug resistant pathogen, which is responsible for increasing cases of serious diseases, including life-threatening diseases and nosocomial and community-acquired infections. Laboratory identification of MRSA is crucial and essential both for initiation of appropriate antimicrobial therapies and for effective infection control strategies that are designed to limit the spread of MRSA. In spite of the availability of commercial kits for MRSA detection in the market, the Clinical and Laboratory Standards Institute (CLSI) recommends the use of phenotypic methods, such as the disk diffusion method with oxacillin or with cefoxitin, as well as a serial dilution method with oxacillin. Nevertheless, some studies have shown that results obtained with such phenotypic methods are controversial. The aim of the study described in this paper was to comparatively evaluate the traditional susceptibility testing for MRSA with PCR as the gold standard assay. Analysis of collection (n = 68) isolates of Staphylococcus aureus revealed that the serial dilution method with oxacillin possessed the highest sensitivity (at 100%). In contrast, the disk diffusion methods with oxacillin and cefoxitin showed lower sensitivity (95.83%, 95% CI (78.81%-99.30%)). Furthermore, the borderline value of zone inhibition diameters for cefoxitin might be considered as a risk, and they may give false-susceptible result.
Evaluación de Cepas Nativas de Bacillus thuringiensis Como una Alternativa de Manejo Integrado de la Polilla del Tomate (Tuta absoluta Meyrick; Lepidoptera: Gelechiidae) en Chile
Niedmann Lolas,Lorena; Meza-Basso,Luis;
Agricultura Técnica , 2006, DOI: 10.4067/S0365-28072006000300002
Abstract: the tomato moth (tuta absoluta meyrick; lepidoptera: gelechiidae) is the most devastating insect pest of tomato (lycopersicon esculentum mill.) crops in chile, producing losses from 60 to 100% in non-insecticide treated fields. because pests are evolving to resistance levels to convencional insecticides, there is interest for alternative strategies including the use of biopesticides. in this work the insecticidal potential of native bacillusthuringiensis (bt) strains against this plague was studied. bt isolates were collected from soil samples of the vii region of chile, and characterized using different criteria: colony and parasporal inclusion morphologies, sds-page, western blotting analysis and bioassays against t. absoluta larvae. using the polymerase chain reaction (pcr) technique, a genotype classification was performed using specific primers. all the native strains had genes belonging to cry1 family. two isolates displayed a relevant toxic activity against t. absoluta larvae and could constitute an alternative for controlling this pest. these strains proved to be more effective than the isolate obtained from the commercial dipel bt formulation (b. thuringiensis var. kurstaki).
McFarland nephelometer as a simple method to estimate the sensitivity of the polymerase chain reaction using Mycobacterium tuberculosis as a research tool
Bollela, V.R.;Sato, D.N.;Fonseca, B.A.L.;
Brazilian Journal of Medical and Biological Research , 1999, DOI: 10.1590/S0100-879X1999000900003
Abstract: polymerase chain reaction (pcr) has been widely investigated for the diagnosis of tuberculosis. however, before this technique is applied on clinical samples, it needs to be well standardized. we describe the use of mcfarland nephelometer, a very simple approach to determine microorganism concentration in solution, for pcr standardization and dna quantitation, using mycobacterium tuberculosis as a model. tuberculosis is an extremely important disease for the public health system in developing countries and, with the advent of aids, it has also become an important public health problem in developed countries. using mycobacterium tuberculosis as a research model, we were able to detect 3 m. tuberculosis genomes using the mcfarland nephelometer to assess micobacterial concentration. we have shown here that mcfarland nephelometer is an easy and reliable procedure to determine pcr sensitivity at lower costs.
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