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Increases Sensitivity (increase + sensitivity)
Selected AbstractsNalidixic Acid Resistance Increases Sensitivity of Escherichia coli O157:H7 to Ionizing Radiation in Solution and on Green Leaf LettuceJOURNAL OF FOOD SCIENCE, Issue 2 2005Brendan A. Niemira ABSTRACT: Nalidixic acid resistance has been used as a selective marker for studies of pathogen-inoculated fruits and vegetables. Three nalidixic acid-sensitive outbreak strains of Escherichia coli O157:H7 were used to generate mutants resistant to nalidixic acid (NalR, 50 ,g/mL) by successive culturing and selection in nalidixic acid-amended broth. The resistance to ionizing radiation of the parent and NalR strains was determined (a) in a phosphate buffer solution and (b) on green leaf lettuce. The NalR strains of each of the 3 isolates were significantly (P < 0.05) more sensitive to ionizing radiation than the nalidixic acid-sensitive (NalS) parent strains in both systems. D10 values (the amount of ionizing radiation required to achieve 1 log10 reduction) determined in buffer for the parent strains ranged from 0.18 to 0.33 kGy, whereas for the NalR strains, D10 were approximately 0.10 kGy, a reduction of up to 69%. When evaluated on green leaf lettuce, the D10 for the NalS strains was approximately 0.18 kGy as opposed to 0.10 to 0.12 kGy for the NalR strains, a reduction of up to 45%. The D10 values obtained on lettuce were significantly different than those obtained in buffer for 4 of the 6 isolates examined. The magnitude of the increase in radiation sensitivity resulting from resistance to nalidixic acid varied among the strains tested and also varied depending on the suspending medium. These results suggest that the use of nalidixic acid resistance as a selective marker may result in significant overestimates of the antimicrobial efficacy of ionizing radiation against E. coli O157:H7. [source] The influence of natural variations in maternal care on play fighting in the ratDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2008Carine I. Parent Abstract Naturally occurring variations in maternal care in the rat influence the sensitivity of offspring to stress in adulthood. The offspring of mothers that show lower levels of pup licking/grooming (i.e., low-LG mothers) demonstrate enhanced responses to stress and increased anxiety compared to those of high-LG mothers. Low-LG offspring are also more sensitive to the influence of environmental enrichment than high-LG offspring. This study examined play fighting in the juvenile offspring of high-LG and low-LG dams in a multiple-play partners housing environment. Male offspring from low-LG dams demonstrated a significantly higher frequency of pouncing, pinning and aggressive social grooming than did high-LG males and high-LG and low-LG females. Consistent with earlier reports, male pups engaged in more play fighting than did females and maternal care was associated with differences in play fighting but only in males. Lower levels of stimulation in the form of LG from the dam during perinatal development may thus increase sensitivity for the stimulating effects of play behavior in periadolescence, in part explaining the increased solicitation of play fighting through increased pouncing in the male offspring of the low-LG mothers. These findings identify a possible influence of variations in maternal care on play fighting and suggest that maternal care in the perinatal period influence social interactions during periadolescence. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 767,776, 2008 [source] Blood morphine levels in naltrexone-exposed compared to non-naltrexone-exposed fatal heroin overdosesADDICTION BIOLOGY, Issue 3 2003DIANE ARNOLD-REED The aim of this study was to investigate the association between prior exposure to naltrexone and increased risk of fatal heroin overdose using a review of toxicology reports for heroin-related fatalities between July 1997 to August 1999 for two groups: those treated with oral naltrexone and those who were not treated. Additional information for the oral naltrexone group was obtained from clinic files. Naltrexone-treated deaths were identified from the patient database at the Australian Medical Procedures Research Foundation (AMPRF), Perth, Western Australia (WA) through the Western Australian Department of Health, Data Linkage Project. Non-treated cases were identified from the database at the Forensic Science Laboratory, State Chemistry Centre (WA). We identified and investigated blood morphine concentrations following 21 fatal heroin overdoses with prior exposure to naltrexone and in 71 non-naltrexone-exposed cases over the same time period. The proportion of deaths where heroin use was a major contributing factor was little different in the non-naltrexone compared to the naltrexone-exposed group. Furthermore, in ,acute opiate toxicity' deaths, blood morphine levels were lower in non-naltrexone-exposed compared with naltrexone-exposed cases. Although there was a higher number of deaths designated as rapid (i.e. occurring within 20 minutes) in the naltrexone-exposed (89%) compared with the non-exposed group (72%) this was not statistically significant. Other drug use in relation to heroin-related fatalities is discussed. Findings do not support the hypothesis that prior exposure to naltrexone increases sensitivity to heroin toxicity. [source] Impaired fear conditioning but enhanced seizure sensitivity in rats given repeated experience of withdrawal from alcoholEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2001D. N. Stephens Abstract Repeated experience of withdrawal from chronic alcohol treatment increases sensitivity to seizures. It has been argued by analogy that negative affective consequences of withdrawal also sensitize, but repeated experience of withdrawal from another sedative-hypnotic drug, diazepam, results in amelioration of withdrawal anxiety and aversiveness. We tested whether giving rats repeated experience of withdrawal from alcohol altered their ability to acquire a conditioned emotional response (CER). Male Hooded Lister rats were fed a nutritionally complete liquid diet as their only food source. Different groups received control diet, or diet containing 7% ethanol. Rats receiving ethanol diet were fed for either 24 days (Single withdrawal, SWD), or 30 days, with two periods of 3 days, starting at day 11, and 21, in which they received control diet (Repeated withdrawal, RWD). All rats were fed lab chow at the end of their liquid diet feeding period. Starting 12 days after the final withdrawal, groups of Control, SWD and RWD rats were given pentylenetetrazole (PTZ; 30 mg/kg, i.p.) three times a week, and scored for seizures. The occurrence of two successive Stage 5 seizures was taken as the criterion for full PTZ kindling. Other groups of control, SWD and RWD rats were trained to operate levers to obtain food, and were then exposed, in a fully counterbalanced design, to light and tone stimuli which predicted unavoidable footshock (CS+), or which had no consequences (CS,). Rats consumed approximately 17.5 g/kg/day of ethanol, resulting in blood alcohol levels of approximately 100 mg/dL. Repeated administration of PTZ resulted in increasing seizure scores. RWD rats achieved kindling criterion faster than either Control or SWD rats. No differences were seen in the groups in flinch threshold to footshock (0.3 mA). At a shock intensity of 0.35 mA, Control, but not RWD or SWD rats showed significant suppression to the CS+ CS, presentation did not affect response rates. The three groups differed in their response to pairing the CS+ with increasing shock levels, the Controls remaining more sensitive to the CS+. SWD rats showed significant suppression of lever pressing during CS+ presentations only at 0.45 and 0.5 mA, and RWD rats only at 0.5 mA. Giving rats repeated experience of withdrawal from chronic ethanol results in increased sensitivity to PTZ kindling, but reduces their ability to acquire a CER. Withdrawal kindling of sensitivity to anxiogenic events does not seem to occur under circumstances which give rise to kindling of seizure sensitivity. [source] MicroRNA-143 reduces viability and increases sensitivity to 5-fluorouracil in HCT116 human colorectal cancer cellsFEBS JOURNAL, Issue 22 2009Pedro M. Borralho MicroRNAs are aberrantly expressed in cancer; microRNA-143 (miR-143) is down-regulated in colon cancer. HCT116 human colorectal cancer cells were used to investigate the biological role of miR-143. Transient miR-143 overexpression resulted in an approximate 60% reduction in cell viability. In addition, stable miR-143 overexpressing cells were selected with G418 and exposed to 5-fluorouracil. Increased stable expression of miR-143 was associated with decreased viability and increased cell death after exposure to 5-fluorouracil. These changes were associated with increased nuclear fragmentation and caspase -3, -8 and -9 activities. In addition, extracellular-regulated protein kinase 5, nuclear factor-,B and Bcl-2 protein expression was down-regulated by miR-143, and further reduced by exposure to 5-fluorouracil. In conclusion, miR-143 modulates the expression of key proteins involved in the regulation of cell proliferation, death and chemotherapy response. In addition, miR-143 increases the sensitivity of colon cancer cells to 5-fluorouracil, probably acting through extracellular-regulated protein kinase 5/nuclear factor-,B regulated pathways. Collectively, the data obtained in the present study suggest anti-proliferative, chemosensitizer and putative pro-apoptotic roles for miR-143 in colon cancer. [source] Detection of Mollicutes in bioreactor samples by real-time transcription-mediated amplificationLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2010S. Laborde Abstract Aim:, Contamination by Mollicutes is a significant challenge for research laboratories and biopharmaceutical industry. It leads to alteration of results or production quality as well as loss of time, materials and revenue. These organisms can czoriginate from mammalian, avian, insect, plant or fish cells. Culture-based methods may require 28 days to detect Mollicutes. Traditional microbiology could advantageously be replaced by nucleic acid testing for earlier detection. Methods and Results:, A membrane filtration-based concentration of the Mollicutes has been coupled to real-time transcription-mediated amplification (real-time TMA) to demonstrate these advantages. The eight species required by European Pharmacopoeia have been tested and were detected with sensitivity below 100 CFU per 20-ml sample. Co-culture experiments, in which Mollicutes are grown with CHO-S (suspension) or HEK 293 (adherent) cells, were also performed to respectively mimic a bioreactor or flask contamination. Despite the fact that Mollicutes can attach to or invade mammalian cells, they were consistently detected over multiple days. Conclusions:, the sample preparation and amplification method used in this study increases sensitivity and reduces time-to-result for detection of Mollicutes. Significance and Impact of the Study:, the described system allows real-time monitoring for microbial contamination of cell-based processes and products for the biopharmaceutical industry. [source] Technical Note: Grading the vertical cup:disc ratio and the effect of scalingOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2007Ruth Bennett Abstract Purpose:, To evaluate the effect of scaling on sensitivity to change for grading the vertical cup:disc ratio (CDR). Methods:, Vertical CDR was assessed by six observers (three ophthalmologists and three optometrists) on 43 stereo disc photographs. Repeated observations were made for both 0.1 and 0.05 interval scales. Paired differences were calculated for all observers and each observer separately. Mean and standard deviation of differences and agreement statistics were used to compare scales. Results:, Five observers demonstrated a reduction in the spread of differences (mean difference 0.19 to 0.15) and all observers demonstrated a reduction in concordance using the finer scale (mean concordance 54% to 39%). Conclusion:, The use of a finer scale reduces test,retest variability and increases sensitivity to change when estimating the vertical CDR. Use of this scale does not require any additional resource and it may be easily implemented in routine clinical practice. [source] Screening cancer patients' families with the distress thermometer (DT): a validation studyPSYCHO-ONCOLOGY, Issue 10 2008Diana Zwahlen Abstract Although family members of cancer patients are at great risk of experiencing psychological distress, clinical tools to assist with recognizing and intervening with appropriate psychosocial care are sparse. This study reports on the first validation of the distress thermometer (DT) as a screening instrument for symptoms of depression and anxiety in family members of cancer patients. The DT was administered with the Hospital Anxiety and Depression Scale (HADS) in a sample of 321 family members. Receiver operating characteristics (ROC) demonstrated that the DT has good diagnostic utility relative to the HADS (area under the curve= 0.88 relative to the HADS anxiety scale; 0.84 relative to the HADS depression scale, respectively). The ROC curves indicate that using a cut-off of 4/5 maximizes sensitivity (86.2% HADS anxiety scale; 88.2% HADS depression scale) and specificity (71.2% HADS anxiety scale; 67.6% HADS depression scale); however, the alternative lower cut-off of 3/4 increases sensitivity (94.1% for both scales) and hence reduces the risk of missing distressed family members (specificity is 62.9% for HADS anxiety scale; 59.1% for HADS depression scale). The results offer validation of the DT for screening family members of cancer patients and support its use for clinical assessment. Distress screening with DT for family members of cancer patients is a promising and efficient approach to integrating family members in the program of care and provides the first step toward meeting their unmet needs with referral for supportive services. Copyright © 2008 John Wiley & Sons, Ltd. [source] Overexpression of 5,-reductase type 1 increases sensitivity of prostate cancer cells to low concentrations of testosteroneTHE PROSTATE, Issue 6 2009Lynn N. Thomas Abstract INTRODUCTION Conversion of testosterone to dihydrotestosterone (DHT) by the enzymes 5,-reductase types 1 (5,R1) and 2 (5,R2) is important for normal and pathological growth of the prostate. The predominant isoenzyme in normal prostate is 5,R2. However, prostate cancer (PCa) development is accompanied by a decrease in 5,R2 and an increase in 5,R1. The biological significance of increased 5,R1 expression is not fully understood. Therefore, the aim of this study was to determine the effect of overexpression of 5,R1 on growth and prostate-specific antigen (PSA) production in PCa cells. MATERIALS AND METHODS LNGK-9 PCa cells, transiently transfected with pTRE-5,R1 or pTRE alone, were cultured in the presence or absence of testosterone at varying concentrations. Cell growth and PSA secretion were measured after 4,6 days. Cyclin E1, Ki67, and PSA mRNA levels were evaluated using RT-PCR after 24 hr of treatment. RESULTS 10 pM testosterone increased growth of pTRE-5,R1 transfectants by 54.1% over cells grown in the absence of testosterone, compared to 25.0% in pTRE transfectants (P,<,0.01). Likewise, PSA secretion was increased by 56-fold in pTRE-5,R1 transfectants treated with 10 pM testosterone, compared to 26-fold in pTRE transfectants (P,<,0.01). At concentrations of testosterone above 10 pM, the stimulatory effect on growth and PSA secretion was not distinguishable between pTRE-5,R1 and pTRE transfectants. CONCLUSIONS These results demonstrate that upregulation of 5,R1 enhances the cellular response to low, but not high, concentrations of testosterone. This explains one mechanism by which castration-recurrent PCa can proliferate in the presence of castrate levels of circulating testosterone. Prostate 69:595,602, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||||||||