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Resistance Studies (resistance + studies)
Selected AbstractsDetection of Helicobacter pylori DNA by a Simple Stool PCR Method in Adult Dyspeptic PatientsHELICOBACTER, Issue 4 2005Nazime ABSTRACT Introduction.,Helicobacter pylori is the major agent causing peptic ulcer, gastric cancer and mucosa-associated lymphoid tissue (MALT) gastric lymphoma. A simple stool polymerase chain reaction (PCR) method was performed and compared with the gold standards for the diagnosis of H. pylori infection. Material and methods., A total of 54 adult patients (mean age, 46.41 ± 13.12 years) with dyspeptic symptoms from Gastroenterology at Dokuz Eylül University Hospital between May and November 2003 were included. Two antrum and corpus biopsies were taken from each patient. Infection by H. pylori was defined as positivity and negativity of the gold standards. DNA extraction of stool specimens was done using QIAamp DNA Stool Mini Kit (QIAGEN) and PCR conditions included amplification and reamplification steps using the H. pylori ureA gene specific primers (HPU1, HPU2) and were visualized on 1% agarose gel stained with ethidium bromide. Results., Forty-six of 54 patients (85.2%) were diagnosed positive and eight (14.8%) were negative for H. pylori infection by the gold standard methods. Thirty-two patients were positive (59.3%) and 22 of them (40.7%) were detected negative by stool PCR method. The stool PCR method and gold standard methods showed a statistical difference for the detection of H. pylori infection (p < .0001). Sensitivity, specificity, likelihood ratio, and positive and negative predictive values were 65.22%, 75%, 2.61%, 93.75%, and 27.7%, respectively. Discussion., The PCR on the stool specimens resulted as being a very specific test. We suggest that a simple stool PCR method that we developed can be used to detect H. pylori, virulence genes, and in drug resistance studies either first line diagnostic methods in the laboratory or in the clinical management of dyspeptic patients. [source] A survey for serotyping, antibiotic resistance profiling and PFGE characterization of and the potential multiplication of restaurant Salmonella isolatesJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2007D.J. Bolton Abstract Aims: The aims of this research were (1) to determine the occurrence of Salmonella in Irish restaurant kitchens and (2) to investigate the serovar, genotype, antibiotic resistance profile and survival/growth profile of the Salmonella under catering chilled storage and temperature abuse conditions. Methods: Five sites/tools in each of 200 randomly selected restaurant kitchens were examined for the presence of presumptive Salmonella spp. by enrichment. Serotyping, antibiotic resistance studies and genotyping were performed using the Kauffmann-White, CLSI and PulseNet methods, respectively. Survival/growth was investigated in milk, meat and vegetable products. Results: Presumptive isolates from 15 of the 200 restaurant kitchens were recovered and confirmed as Salmonella positive. Seven different serovars showing a variety of antibiotic resistance profiles were detected. PFGE profiles suggested that isolates from geographically adjacent restaurants were related. Salmonella survived in foods stored at typical catering refrigeration temperatures and increased by approximately 0·8 log10 CFU ml,1 per day in food products stored under conditions of thermal abuse (20°C). Conclusions: Inadequate hygiene has resulted in contamination of restaurant kitchens with Salmonella, which may persist/multiply in cross-contaminated foods. Significance and Impact of the Study: This study highlights the need for greater hygiene in restaurant kitchens coupled with rapid chilling of food not for immediate consumption and reheating before subsequent serving. [source] Effect of sporulation and recovery medium on the heat resistance and amount of injury of spores from spoilage bacilliJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2001A.E. Cazemier Aims:,To assess the influence of sporulation media on heat resistance, and the use of stress recovery media to measure preservation injury of spores of five representative spoilage bacilli. Methods and Results:,Bacillus spores prepared on nutrient agar supplemented with Ca2+, Mg2+, Mn2+, Fe2+ and K+ were more heat-resistant than spores obtained from nutrient agar with Mn2+. This increased heat resistance correlated with a decrease in the protoplast water content as determined by buoyant density sedimentation. The degree of preservation injury severity could be assessed on media containing NaCl at moderate pH and organic acids at acid pH. Ca-DPA, K+ or proline were added to the recovery media to demonstrate that heat probably caused injury to both spore germination and the outgrowth system. Significance and Impact of the Study:,The metal content of sporulation media can strongly effect the validity of preservation resistance studies. The distinctive recovery media developed here can be relevant for assessing and comparing new preservation technologies. [source] Delivery of nerve growth factor to brain via intranasal administration and enhancement of brain uptakeJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2009Siva Ram Kiran Vaka Abstract The main objective of the study was to investigate the efficacy of chitosan to facilitate brain bioavailability of intranasally administered nerve growth factor (NGF). In vitro permeability studies and electrical resistance studies were carried out across the bovine olfactory epithelium using Franz diffusion cells. The bioavailability of intranasally administered NGF in rat hippocampus was determined by carrying out brain microdialysis in Sprague,Dawley rats. The in vitro permeation flux across the olfactory epithelium of NGF solution without chitosan (control) was found to be 0.37,±,0.06 ng/cm2/h. In presence of increasing concentration of chitosan (0.1%, 0.25%, and 0.5%, w/v) the permeation flux of NGF was found to be 2.01,±,0.12, 3.88,±,0.19, and 4.12,±,0.21 ng/cm2/h respectively. Trans-olfactory epithelial electrical resistance decreased ,34.50,±,4.06% in presence of 0.25% (w/v) chitosan. The Cmax in rats administered with 0.25% (w/v) chitosan and NGF was 1008.62,±,130.02 pg/mL, which was significantly higher than that for rats administered with NGF only 97.38,±,10.66 pg/mL. There was ,14-fold increase in the bioavailability of intranasally administered NGF with chitosan than without chitosan. Chitosan can enhance the brain bioavailability of intranasally administered NGF. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3640,3646, 2009 [source] Silicon-augmented resistance of plants to herbivorous insects: a reviewANNALS OF APPLIED BIOLOGY, Issue 2 2009O.L. Reynolds Abstract Silicon (Si) is one of the most abundant elements in the earth's crust, although its essentiality in plant growth is not clearly established. However, the importance of Si as an element that is particularly beneficial for plants under a range of abiotic and biotic stresses is now beyond doubt. This paper reviews progress in exploring the benefits at two- and three-trophic levels and the underlying mechanism of Si in enhancing the resistance of host plants to herbivorous insects. Numerous studies have shown an enhanced resistance of plants to insect herbivores including folivores, borers, and phloem and xylem feeders. Silicon may act directly on insect herbivores leading to a reduction in insect performance and plant damage. Various indirect effects may also be caused, for example, by delaying herbivore establishment and thus an increased chance of exposure to natural enemies, adverse weather events or control measures that target exposed insects. A further indirect effect of Si may be to increase tolerance of plants to abiotic stresses, notably water stress, which can in turn lead to a reduction in insect numbers and plant damage. There are two mechanisms by which Si is likely to increase resistance to herbivore feeding. Increased physical resistance (constitutive), based on solid amorphous silica, has long been considered the major mechanism of Si-mediated defences of plants, although there is recent evidence for induced physical defence. Physical resistance involves reduced digestibility and/or increased hardness and abrasiveness of plant tissues because of silica deposition, mainly as opaline phytoliths, in various tissues, including epidermal silica cells. Further, there is now evidence that soluble Si is involved in induced chemical defences to insect herbivore attack through the enhanced production of defensive enzymes or possibly the enhanced release of plant volatiles. However, only two studies have tested for the effect of Si on an insect herbivore and third trophic level effects on the herbivore's predators and parasitoids. One study showed no effect of Si on natural enemies, but the methods used were not favourable for the detection of semiochemical-mediated effects. Work recently commenced in Australia is methodologically and conceptually more advanced and an effect of Si on the plants' ability to generate an induced response by acting at the third trophic level was observed. This paper provides the first overview of Si in insect herbivore resistance studies, and highlights novel, recent hypotheses and findings in this area of research. Finally, we make suggestions for future research efforts in the use of Si to enhance plant resistance to insect herbivores. [source] | ||||||||||