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Relative Sensitivity (relative + sensitivity)
Selected AbstractsRelative sensitivity of bull trout (Salvelinus confluentus) and rainbow trout (Oncorhynchus mykiss) to acute copper toxicityENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2002James A. Hansen Abstract Bull trout (Salvelinus confluentus) were recently listed as threatened in the United States under the federal Endangered Species Act. Past and present habitat for this species includes waterways contaminated with heavy metals released from mining activities. Because the sensitivity of this species to copper was previously unknown, we conducted acute copper toxicity tests with bull and rainbow trout (Oncorhynchus mykiss) in side-by-side comparison tests. Bioassays were conducted using water at two temperatures (8°C and 16°C) and two hardness levels (100 and 220 mg/L as CaCO3). At a water hardness of 100 mg/L, both species were less sensitive to copper when tested at 16°C compared to 8°C. The two species had similar sensitivity to copper in 100-mg/L hardness water, but bull trout were 2.5 to 4 times less sensitive than rainbow trout in 220-mg/L hardness water. However, when our results were viewed in the context of the broader literature on rainbow trout sensitivity to copper, the sensitivities of the two species appeared similar. This suggests that adoption of toxicity thresholds that are protective of rainbow trout would be protective of bull trout; however, an additional safety factor may be warranted because of the additional level of protection necessary for this federally threatened species. [source] Detection of Acute Diazepam Exposure in Bone and Marrow: Influence of Tissue Type and the Dose-Death Interval on Sensitivity of Detection by ELISA with Liquid Chromatography Tandem Mass Spectrometry Confirmation,JOURNAL OF FORENSIC SCIENCES, Issue 3 2009D.A.B.F.T., James H. Watterson Ph.D. Abstract:, Enzyme-linked immunosorbent assay (ELISA) and liquid chromatography tandem mass spectrometry (LC/MS/MS) were used to detect diazepam exposure in skeletal tissues of rats (n = 15) given diazepam acutely (20 mg/kg, i.p.), and killed at various times postdose. Marrow, epiphyseal, and diaphyseal bone were isolated from extracted femora. Bone was cleaned, ground, and incubated in methanol. Marrow underwent ultrasonic homogenization. Extracts and homogenates were diluted in phosphate buffer, and then underwent solid-phase extraction and ELISA. Relative sensitivity of detection was examined in terms of relative decrease in absorbance (ELISA) and binary classification sensitivity (ELISA and LC/MS/MS). Overall, the data showed differences in relative sensitivity of detection of diazepam exposure in different tissue types (marrow > epiphyseal bone > diaphyseal bone), which is suggestive of heterogenous distribution in these tissues, and a decreasing sensitivity with increasing dose-death interval. Thus, the tissue type sampled and dose-death interval may contribute to the probability of detection of diazepam exposure in skeletal tissues. [source] Ecological responses to altered flow regimes: a literature review to inform the science and management of environmental flowsFRESHWATER BIOLOGY, Issue 1 2010N. LEROY POFF Summary 1.,In an effort to develop quantitative relationships between various kinds of flow alteration and ecological responses, we reviewed 165 papers published over the last four decades, with a focus on more recent papers. Our aim was to determine if general relationships could be drawn from disparate case studies in the literature that might inform environmental flows science and management. 2.,For all 165 papers we characterised flow alteration in terms of magnitude, frequency, duration, timing and rate of change as reported by the individual studies. Ecological responses were characterised according to taxonomic identity (macroinvertebrates, fish, riparian vegetation) and type of response (abundance, diversity, demographic parameters). A ,qualitative' or narrative summary of the reported results strongly corroborated previous, less comprehensive, reviews by documenting strong and variable ecological responses to all types of flow alteration. Of the 165 papers, 152 (92%) reported decreased values for recorded ecological metrics in response to a variety of types of flow alteration, whereas 21 papers (13%) reported increased values. 3.,Fifty-five papers had information suitable for quantitative analysis of ecological response to flow alteration. Seventy per cent of these papers reported on alteration in flow magnitude, yielding a total of 65 data points suitable for analysis. The quantitative analysis provided some insight into the relative sensitivities of different ecological groups to alteration in flow magnitudes, but robust statistical relationships were not supported. Macroinvertebrates showed mixed responses to changes in flow magnitude, with abundance and diversity both increasing and decreasing in response to elevated flows and to reduced flows. Fish abundance, diversity and demographic rates consistently declined in response to both elevated and reduced flow magnitude. Riparian vegetation metrics both increased and decreased in response to reduced peak flows, with increases reflecting mostly enhanced non-woody vegetative cover or encroachment into the stream channel. 4.,Our analyses do not support the use of the existing global literature to develop general, transferable quantitative relationships between flow alteration and ecological response; however, they do support the inference that flow alteration is associated with ecological change and that the risk of ecological change increases with increasing magnitude of flow alteration. 5.,New sampling programs and analyses that target sites across well-defined gradients of flow alteration are needed to quantify ecological response and develop robust and general flow alteration,ecological response relationships. Similarly, the collection of pre- and post-alteration data for new water development programs would significantly add to our basic understanding of ecological responses to flow alteration. [source] Early detection of radiation therapy response in non-Hodgkin's lymphoma xenografts by in vivo1H magnetic resonance spectroscopy and imagingNMR IN BIOMEDICINE, Issue 6 2010Seung-Cheol Lee Abstract The purpose of the study was to investigate the capability of 1H MRS and MRI methods for detecting early response to radiation therapy in non-Hodgkin's lymphoma (NHL). Studies were performed on the WSU-DLCL2 xenograft model in nude mice of human diffuse large B-cell lymphoma, the most common form of NHL. Radiation treatment was applied as a single 15,Gy dose to the tumor. Tumor lactate, lipids, total choline, T2 and apparent diffusion coefficients (ADC) were measured before treatment and at 24,h and 72,h after radiation. A Hadamard-encoded slice-selective multiple quantum coherence spectroscopy sequence was used for detecting lactate (Lac) while a stimulated echo acquisition mode sequence was used for detection of total choline (tCho) and lipids. T2 - and diffusion-weighted imaging sequences were used for measuring T2 and ADC. Within 24,h after radiation, significant changes were observed in the normalized integrated resonance intensities of Lac and the methylenes of lipids. Lac/H2O decreased by 38,±,15% (p,=,0.03), and lipid (1.3,ppm, CH2)/H2O increased by 57,±,14% (p,=,0.01). At 72,h after radiation, tCho/H2O decreased by 45,±,14% (p,=,0.01), and lipid (2.8,ppm, polyunsaturated fatty acid)/H2O increased by 970,±,36% (p,=,0.001). ADC increased by 14,±,2% (p,=,0.003), and T2 did not change significantly. Tumor growth delay and regression were observed thereafter. This study enabled comparison of the relative sensitivities of various 1H MRS and MRI indices to radiation and suggests that 1H MRS/MRI measurements detect early responses to radiation that precede tumor volume changes. Copyright © 2010 John Wiley & Sons, Ltd. [source] Temporal detection in human vision: dependence on eccentricityOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2002R. F. Hess Studies of human perception of time-varying luminance often aim to estimate either temporal impulse response shapes or temporal modulation transfer functions (MTFs) of putative temporal processing mechanisms. Previously, temporal masking data have been used to estimate the properties and numbers of these temporal mechanisms in central vision for 1 cycle per degree (cpd) targets [Fredericksen and Hess (1998)]. The same methods have been used to explore how these properties change with stimulus energy [Fredericksen and Hess (1997)] and spatial frequency [Fredericksen and Hess (1999)]. We present here analyses of the properties of temporal mechanisms that detect temporal variations of luminance in peripheral vision. The results indicate that a two-filter model provides the best model for our masking data, but that no multiple filter model provides an acceptable fit across the range of parameters varied in this study. Single-filter modelling shows differences between processing mechanisms at 1 cpd in central vision and those that operate eccentrically. We find evidence that this change is because of differences in relative sensitivities of the mechanisms, and to differences in fundamental mechanism impulse responses. [source] A comparison of fetal organ measurements by echo-planar magnetic resonance imaging and ultrasoundBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 1 2005Keith R. Duncan Objectives To compare fetal organ size measured using echo-planar magnetic resonance imaging and 2D ultrasound. To determine the relative accuracy with which each technique can predict fetal growth restriction. Design A cross sectional, observational study comparing two different measurement techniques against a gold standard, in a normal clinical population and an abnormal population. Setting and Population Seventy-four pregnant women (33 who were ultimately found to be normal and 37 with fetal growth restricted fetuses) were recruited from the City Hospital Nottingham UK to be scanned once (at various gestations). Methods Each fetus had a standard ultrasound biometry assessment followed by magnetic resonance imaging measurement of organ volumes. Main outcome measures For each measurement for both techniques, the normal population was plotted with 90% confidence intervals. Fetal growth restricted subjects were compared with the normal population using this plot; 2 × 2 tables were created for each measurement. This was used to calculate the relative sensitivities and positive predictive value of the different measurements. A Bland,Altman plot was used to compare the ultrasound and magnetic resonance imaging measurements of fetal weight. Results Brain sparing was seen in ultrasonic head circumference measurements, but an overall reduction in fetal growth restriction brain volume was apparent using magnetic resonance imaging at late gestations. Across the whole range of gestational ages, ultrasound assessment of fetal weight was the best predictor of fetal growth restriction. Conclusion Ultrasound fetal weight assessment appears to identify more fetuses with fetal growth restriction than abdominal circumference. The brain sparing apparent in ultrasonic head circumference measurements of fetuses with fetal growth restriction masks a reduction in brain volume observed with magnetic resonance imaging. [source] The U.S. Share of Trading Volume in Cross-Listings: Evidence from Canadian StocksFINANCIAL REVIEW, Issue 1 2007Sanjiv Sabherwal G10; G14; G15 Abstract I analyze the firm-specific determinants of the U.S. share of trading volume for 126 U.S.-listed Canadian firms. I find that the U.S. share of volume is directly related to the mass of informed and liquidity traders in the United States relative to Canada, as proxied by relative analyst following, relative duration of listing, and the U.S. share of sales. Evidence also supports the market liquidity argument that the market with lower spreads and greater depths has greater volume. Finally, the U.S. share is directly related to the relative sensitivity of the stock's value to information in the United States. [source] The relative sensitivity of willingness-to-pay and time-trade-off to changes in health status: an empirical investigationHEALTH ECONOMICS, Issue 6 2001Richard D. Smith Abstract This paper directly compares the relative sensitivity of time-trade-off (TTO) and willingness-to-pay (WTP) values obtained for various levels of change in health status. This was achieved by administering a TTO and WTP survey to a population of 50 subjects, assessing their valuation of various degrees of change in health status. It was found that, overall, WTP is more sensitive than TTO in distinguishing between different dimensions of health at the same nominal level of health status (only four WTP values not significantly different, compared with eight TTO values). In addition, WTP was also more sensitive to differences in quality of life between different levels of health within each dimension (all values significantly different from each other, with TTO yielding three insignificant relationships). These results tentatively suggest, therefore, that WTP seems to be a more sensitive measure of change in health status than TTO. Copyright © 2001 John Wiley & Sons, Ltd. [source] Consumer credit and monetary policy in MalaysiaINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 3 2008Salina Hj. Abstract What is the impact of monetary policy on the Malaysian consumer? The study addresses this issue by empirically investigating the consequences of interest rate shocks on consumer credit in Malaysia. The study relies on the impulse response functions and the variance decomposition analysis based on the structural Vector Auto-regression methodology. Apart from analysing the responses of aggregate consumer loans (ACL) to interest rate changes, further disaggregation is made in efforts to arrive at more detailed findings. In particular, the ACL data are categorized into loans for purchase of residential property, loans for personal uses, loans for credit cards, loans for purchase of consumer durables, loans for purchase of passenger cars and loans for purchase of securities. Through this disaggregation, the study shows the relative sensitivity of the various types of consumer loans to interest rate shocks. [source] Consumer sensitivity to changes in tax policy on consumption of alcoholINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 3 2006David E. Smith Abstract Marketers and economists have followed the consumption patterns of alcoholic beverages for many years. Public officials have studied the negative effects of consuming alcohol and have advocated a variety of measures to curtail consumption. Previous studies have also measured the price elasticity. This comparative study is based on a 40-year analysis, and compares the consumption patterns for beer, spirits and wine in three Nordic countries. Although the cultural context of Denmark, Norway and Sweden are similar, nevertheless significant differences in the patterns of consumption and prices for alcoholic beverages have been evidenced overtime. A comparison of the per capita drinking patterns and the taxation effectiveness are presented. Even though the elasticities varied, the data indicate relative sensitivity to price changes and a decline in spirits consumption as well as switching effects to lower alcohol-content beverages. [source] Band gaps and the possible effect on impact sensitivity for some nitro aromatic explosive materialsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 7 2009Hong Zhang Abstract The first principle density functional theory method SIESTA has been used to compute the band gap of several polynitroaromatic explosives, such as TATB, DATB, TNT, and picric acid. In these systems, the weakest bond is the one between an NO2 group and the aromatic ring. The bond dissociation energy (BDE) alone cannot predicate the relative sensitivity to impact of these four systems correctly. It was found that their relative impact sensitivity could be explained by considering the BDE and the band gap value of the crystal state together. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Virulent spores of Bacillus anthracis and other Bacillus species deposited on solid surfaces have similar sensitivity to chemical decontaminantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007J-L. Sagripanti Abstract Aims:, To compare the relative sensitivity of Bacillus anthracis and spores of other Bacillus spp. deposited on different solid surfaces to inactivation by liquid chemical disinfecting agents. Methods and Results:, We prepared under similar conditions spores from five different virulent and three attenuated strains of B. anthracis, as well as spores of Bacillus subtilis, Bacillus atrophaeus (previously known as Bacillus globigii), Bacillus cereus, Bacillus thuringiensis and Bacillus megaterium. As spore-surface interactions may bias inactivation experiments, we evaluated the relative binding of different spores to carrier materials. The survival of spores deposited on glass, metallic or polymeric surfaces were quantitatively measured by ASTM standard method E-2414-05 which recovers spores from surfaces by increasing stringency. The number of spores inactivated by each decontaminant was similar and generally within 1 log among the 12 different Bacillus strains tested. This similarity among Bacillus strains and species was observed through a range of sporicidal efficacy on spores deposited on painted metal, polymeric rubber or glass. Conclusions:, The data obtained indicate that the sensitivity of common simulants (B. atrophaeus and B. subtilis), as well as spores of B. cereus, B. thuringiensis, and B. megaterium, to inactivation by products that contain either: peroxide, chlorine or oxidants is similar to that shown by spores from all eight B. anthracis strains studied. Significance and Impact of the Study:, The comparative results of the present study suggest that decontamination and sterilization data obtained with simulants can be safely extrapolated to virulent spores of B. anthracis. Thus, valid conclusions on sporicidal efficacy could be drawn from safer and less costly experiments employing non-pathogenic spore simulants. [source] Comparison of the specificity and sensitivity of traditional methods for assessment of nephrotoxicity in the rat with metabonomic and proteomic methodologiesJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2005Andy Gibbs Abstract There is currently a great deal of scientific interest and debate concerning the possible advantages that proteomic and metabonomic technologies might have over traditional biomarkers of toxicity (blood and urine chemistry, histopathology). Numerous papers have been published that make impressive claims concerning potential applications for these novel technologies, however there appears to be little hard evidence in the literature of their advantages over the traditional techniques for assessing toxicity. The aim of this review was to evaluate the relative sensitivity and specificity of proteomic and metabonomic techniques, compared with traditional techniques, for assessing xenobiotic-induced nephrotoxicity. A review of studies was performed where both one of the novel methods as well as traditional techniques were used for assessment of xenobiotic-induced nephrotoxicity. There was no consistent evidence from the literature that the novel methodologies were any more sensitive than the traditional methods for assessing nephrotoxicity. This could be due to the relatively small number of studies available for review (n = 13), the fact that generally these studies were not aimed at determining relative sensitivity or specificity and may not be the case with other target organs, such as the liver. However, it was clear that the novel methodologies were able to discriminate between the effects caused by different toxicants. There was evidence both that this discrimination was on the basis of different mechanisms of toxicity and on the basis of different locations of nephrotoxic lesion. A great deal of validation work is necessary before these techniques could gain full acceptance by regulatory authorities, and it is unclear whether their use in anything other than non-regulatory, mechanistic studies is likely to become widespread. Copyright © 2005 John Wiley & Sons, Ltd. [source] Role of sonography in diagnosing and staging invasive lobular carcinomaJOURNAL OF CLINICAL ULTRASOUND, Issue 7 2004Veronica L. Selinko MD Abstract Purpose The goal of this study was to compare the sensitivity of sonography with that of mammography in the detection of invasive lobular carcinoma (ILC), to identify ILC's typical imaging characteristics, and to further show the important role of ultrasound in the staging and treatment planning of this elusive tumor. Methods We identified all patients with ILC seen at our institution from 1998 through 2001; 62 had pathologically proven pure ILC. We retrospectively reviewed and analyzed the sonographic appearances in correlation with mammographic, pathologic, and clinical findings. We reviewed the results of sonographic examinations of the nodal basins and fine-needle aspiration (FNA) of suspicious nodes and correlated them with initial clinical and final pathologic staging. We noted all cases of multicentricity or multifocality and analyzed the relative sensitivity of mammography and sonography according to tumor size. Results Sonography had a sensitivity of 98% versus 65% for mammography. The most common mammographic pattern was a spiculated mass or architectural distortion (39%). On sonography the most common pattern was a hypoechoic mass with (58%) or without (27%) shadowing. An infiltrative pattern was observed in 13% of the cases. Ultrasound-guided FNA confirmed disease was present in the axillary lymph nodes in 21% of the patients, and sonographic examination of the nodal basins resulted in a change of clinical staging from N0 to N1 in 75% and from N1 to N0 in 30% of the cases. Multicentricity/multifocality was identified sonographically and proved by FNA in 21% of patients. Conclusions Sonography has a much higher sensitivity than mammography in detecting ILC and therefore is an important adjunctive tool in the diagnosis of this form of cancer. Routine examination of node-bearing areas in patients with ILC proved useful in refining the disease staging. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:323,332, 2004 [source] Mechanisms of pathogenesis and the evolution of parasite virulenceJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2008S. A. FRANK Abstract When studying how much a parasite harms its host, evolutionary biologists turn to the evolutionary theory of virulence. That theory has been successful in predicting how parasite virulence evolves in response to changes in epidemiological conditions of parasite transmission or to perturbations induced by drug treatments. The evolutionary theory of virulence is, however, nearly silent about the expected differences in virulence between different species of parasite. Why, for example, is anthrax so virulent, whereas closely related bacterial species cause little harm? The evolutionary theory might address such comparisons by analysing differences in tradeoffs between parasite fitness components: transmission as a measure of parasite fecundity, clearance as a measure of parasite lifespan and virulence as another measure that delimits parasite survival within a host. However, even crude quantitative estimates of such tradeoffs remain beyond reach in all but the most controlled of experimental conditions. Here, we argue that the great recent advances in the molecular study of pathogenesis provide a way forward. In light of those mechanistic studies, we analyse the relative sensitivity of tradeoffs between components of parasite fitness. We argue that pathogenic mechanisms that manipulate host immunity or escape from host defences have particularly high sensitivity to parasite fitness and thus dominate as causes of parasite virulence. The high sensitivity of immunomodulation and immune escape arise because those mechanisms affect parasite survival within the host, the most sensitive of fitness components. In our view, relating the sensitivity of pathogenic mechanisms to fitness components will provide a way to build a much richer and more general theory of parasite virulence. [source] Detection of Acute Diazepam Exposure in Bone and Marrow: Influence of Tissue Type and the Dose-Death Interval on Sensitivity of Detection by ELISA with Liquid Chromatography Tandem Mass Spectrometry Confirmation,JOURNAL OF FORENSIC SCIENCES, Issue 3 2009D.A.B.F.T., James H. Watterson Ph.D. Abstract:, Enzyme-linked immunosorbent assay (ELISA) and liquid chromatography tandem mass spectrometry (LC/MS/MS) were used to detect diazepam exposure in skeletal tissues of rats (n = 15) given diazepam acutely (20 mg/kg, i.p.), and killed at various times postdose. Marrow, epiphyseal, and diaphyseal bone were isolated from extracted femora. Bone was cleaned, ground, and incubated in methanol. Marrow underwent ultrasonic homogenization. Extracts and homogenates were diluted in phosphate buffer, and then underwent solid-phase extraction and ELISA. Relative sensitivity of detection was examined in terms of relative decrease in absorbance (ELISA) and binary classification sensitivity (ELISA and LC/MS/MS). Overall, the data showed differences in relative sensitivity of detection of diazepam exposure in different tissue types (marrow > epiphyseal bone > diaphyseal bone), which is suggestive of heterogenous distribution in these tissues, and a decreasing sensitivity with increasing dose-death interval. Thus, the tissue type sampled and dose-death interval may contribute to the probability of detection of diazepam exposure in skeletal tissues. [source] Cerebral Atrophy Measurement in Clinically Isolated Syndromes and Relapsing Remitting Multiple Sclerosis: A Comparison of Registration-Based MethodsJOURNAL OF NEUROIMAGING, Issue 1 2007Valerie M. Anderson BSc ABSTRACT Background and Purpose. Brain atrophy is a proposed marker of disease progression in multiple sclerosis (MS). Many magnetic resonance imaging-based methods of atrophy quantification exist, but their relative sensitivity and precision is unclear. Our aim was to compare atrophy rates from the brain boundary shift integral (BBSI), structural image evaluation, using normalization of atrophy (SIENA) (both registration-based methods) and segmented brain volume difference, in patients with clinically isolated syndromes (CIS), relapsing remitting MS (RRMS), and controls. Methods. Thirty-seven CIS patients, 30 with early RRMS and 16 controls had T1-weighted volumetric imaging at baseline and 1 year. Brain atrophy rates were determined using segmented brain volume difference, BBSI, and SIENA. Results. BBSI and SIENA were more precise than subtraction of segmented brain volumes and were more sensitive distinguishing RRMS subjects from controls. A strong correlation was observed between BBSI and SIENA. Atrophy rates were greater in CIS and RRMS subjects than controls (RRMS P < .001). With all methods, significantly greater atrophy rates were observed in CIS patients who developed clinically definite MS relative to subjects who did not. Conclusion. Registration-based techniques are more precise and sensitive than segmentation-based methods in measuring brain atrophy, with BBSI and SIENA providing comparable results. [source] Comparison of three management strategies for patients with atypical squamous cells of undetermined significance, after six months delay: A three-year experience in an Iranian university hospitalAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2009Fariba YARANDI Background: A Pap test result of atypical squamous cells of undetermined significance (ASCUS) presents a clinical challenge. Only 5,10% of women with ASCUS harbour serious cervical disease. Methods: We screened 3619 women, who attended to Mirza Koochak Khan Hospital at Tehran University of Medical Sciences with Pap smears, of whom 100 returned with ASCUS. After six months, each subject underwent a standard cytology (conventional Pap smear), human papillomavirus (HPV) DNA testing (identifying high-risk HPV types with polymerase chain reaction) and colposcopy with multiple cervical biopsies. Results: Mean age was 44.09 ± 8.6 years. The estimated prevalence of cervical intraepithelial neoplasia (CIN) II or higher was 4%. When histologically verified high-grade lesions (, CIN II) were observed, the relative sensitivity of HPV DNA testing was 100% compared with conventional Pap smear, which performed 75% versus 100% relative sensitivity, respectively, using cytological diagnosis high-grade squamous intraepithelial lesion, or low-grade squamous intraepithelial lesion (LSIL) as the cut-off. Negative and positive predictive values (NPV and PPV) of Pap test were 98.9% and 100%. The NPV and PPV of HPV DNA testing were 100%. Conclusions: Although less complicated than colposcopy, the repeat Pap smear triage algorithm for ASCUS may underdiagnose some women with high-grade CIN, when compared with colposcopy. Considering the high sensitivity of HPV testing, it may be useful as an alternative to the current policy of six-month repeat cytology for women with ASCUS results. [source] Swimming characteristics of magnetic bacterium, Magnetospirillum sp.BIOTECHNOLOGY & BIOENGINEERING, Issue 1 2001AMB-, implications as toxicity measurement Abstract To develop a novel toxicity measurement system using the persistent swimming property of magnetic bacteria along an externally applied magnetic field, certain characteristics of Magnetospirillum sp. AMB-1 cells were examined, including their growth pattern, motility, magnetosensitivity, swimming speed, and cell length distribution. In addition, the effect of toxic compounds on the swimming speed was assessed relative to application as a toxicity sensor. With an inoculum of 1.0 × 108 cells/mL, the cells reached the stationary phase with a concentration of about 5 × 108 cells/mL after 20 h, under both aerobic and anaerobic conditions. The distribution of the cell length did not vary significantly during the growth period, and both aerobically and anaerobically growing cells showed a similar cell length distribution. Although the cells showed similar growth patterns under both conditions, the anaerobically grown cells exhibited higher motility and magnetosensitivity. Actively growing cells under anaerobic conditions had an average swimming speed of 49 ,m/s with a standard deviation of 20 ,m/s. When the anaerobically growing cells were exposed to various concentrations of toxic compounds, such as 1-propanol and acetone, the swimming speed decreased with an increased concentration of the toxic compound. Accordingly, the relationship between swimming speed and toxicity can be used as an effective quantitative toxicity measurement; furthermore, the relative sensitivity of the proposed system was comparable to Microtox, which is commercially available. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 11,16, 2001. [source] | |||||||||||||||||||