Best Sensitivity (best + sensitivity)

Distribution by Scientific Domains

Selected Abstracts

Screening for duct-dependent congenital heart disease with pulse oximetry: A critical evaluation of strategies to maximize sensitivity

Abstract Aim: To evaluate the feasibility of detecting duct-dependent congenital heart disease before hospital discharge by using pulse oximetry. Design: Case-control study. Setting: A supra-regional referral centre for paediatric cardiac surgery in Sweden. Patients: 200 normal term newborns with echocardiographically normal hearts (median age 1.0 d) and 66 infants with critical congenital heart disease (CCHD; median age 3 d). Methods: Pulse oximetry was performed in the right hand and one foot using a new-generation pulse oximeter (NGoxi) and a conventional-technology oximeter (CToxi). Results: With the NGoxi, normal newborns showed a median postductal saturation of 99% (range 94,100%); intra-observer variability showed a mean difference of 0% (SD 1.3%), and inter-observer variability was 0% (SD 1.5%). The CToxi recorded a significantly greater proportion of postductal values below 95% (41% vs 1%) in the normal newborns compared with NGoxi (p < 0.0001). The CCHD group showed a median postductal saturation of 90% (45,99%) with the NGoxi. Analysis of distributions suggested a screening cut-off of < 95%; however, this still gave 7/66 false-negative patients, all with aortic arch obstruction. Best sensitivity was obtained by adding one further criterion: saturation of < 95% in both hand and foot or a difference of > ± 3% between hand and foot. These combined criteria gave a sensitivity of 98.5%, specificity of 96.0%, positive predictive value of 89.0% and negative predictive value of 99.5%. Conclusion: Systematic screening for CCHD with high accuracy requires a new-generation oximeter, and comparison of saturation values from the right hand and one foot substantially improves the detection of CCHD. [source]

Whole, Turret and step methods of rapid rescreening: Is there any difference in performance?

Eliana Borin Lopes Montemor B.Sc.
Abstract We compared the performance of the Whole, Turret and Step techniques of 100% rapid rescreening (RR) in detection of false-negatives in cervical cytology. We tested RR performance with cytologists trained and among those without training. We revised 1,000 consecutive slides from women participating in an ongoing international screening trial. Two teams of experienced cytologists performed the RR techniques: one trained in RR procedures and the other not trained. The sensitivities in the trained group were Whole 46.6%, Turret 47.4% and Step 50.9%; and in the non-trained group were 38.6, 31.6 and 47.4%, respectively. The , coefficient showed a weak agreement between the two groups of cytologists and between the three RR techniques. The RR techniques are more valuable if used by trained cytologists. In the trained group, we did not observe significant differences between the RR techniques used, whereas in the non-trained group, the Step technique had the best sensitivity. Diagn. Cytopathol. 2007;35:57,60. © 2006 Wiley-Liss, Inc. [source]

Detection of C Reactive Protein (CRP) in Serum by an Electrochemical Aptamer-Based Sandwich Assay

Sonia Centi
Abstract A disposable electrochemical assay involving magnetic particles and carbon-based screen-printed electrodes (SPCEs) was developed for the detection of C Reactive Protein (CRP). CRP is a plasma protein and is among the most expressed proteins in acute phase inflammation cases, being a known biomarker for inflammatory states. The assay was based on a sandwich format in which a RNA aptamer was coupled to a monoclonal antibody and alkaline phosphatase (AP) was used as enzymatic label. After the sandwich assay, the modified magnetic beads were captured by a magnet on the surface of a graphite working electrode and the electrochemical detection was thus achieved through the addition of the AP substrate (,-naphthyl-phosphate) and ,-naphthol produced during the enzymatic reaction was detected using differential pulse voltammetry (DPV). The parameters influencing the different steps of the assay were optimized in order to reach the best sensitivity and specificity. With the optimized conditions, the assay was applied to the analysis of CRP free serum and serum samples. [source]

Mercury Detection in Seawater Using a Mercaptoacetic Acid Modified Gold Microwire Electrode

Antje Widmann
Abstract It is demonstrated here that it is possible to determine mercury in chloride containing media like seawater by anodic stripping voltammetry using a modified electrode. A gold microwire electrode is modified using mercaptoacetic acid (MAA) to eliminate the problem of calomel formation, allowing the mercury to become fully removed from the electrode surface after each scan. In a synthetic salt solution of KNO3 the sensitivity for mercury was found to be improved by the surface modification. In seawater the sensitivity was not significantly improved possibly because of complexation of the mercury by the abundant chloride; however, the MAA coating prevented the formation of calomel causing the background scan to be free of mercury. Measurements in seawater at various pH values demonstrated that mercury detection is possible at natural pH (around 8); however, best sensitivity was attained at pH,4.8 with a deposition time of 3,min. A peak for copper occurred at more negative potential but did not interfere at this pH. The calibration was linear between 0 and 37,nM mercury with a limit of detection of 1,nM mercury. [source]

Screening for Abuse and Neglect of People with Dementia

Aileen Wiglesworth PhD
OBJECTIVE: To investigate characteristics of people with dementia and their caregivers (CGs) that are associated with mistreatment in order to inform clinicians about screening for mistreatment. DESIGN: A convenience sample of CG,care recipient (CR) dyads were assessed for literature-supported factors associated with mistreatment, and evidence of mistreatment for the prior year was collected. An expert panel considered the evidence and decided on occurrences of psychological abuse, physical abuse, and neglect based on criteria adopted before data collection. SETTING: Participants' homes. PARTICIPANTS: One hundred twenty-nine persons with dementia and their CGs. MEASUREMENTS: CG and CR characteristics (demographic, health, and psychosocial variables), relationship characteristics, and three elder abuse and neglect detection instruments. RESULTS: Mistreatment was detected in 47.3%. Variables associated with different kinds and combinations of mistreatment types included the CG's anxiety, depressive symptoms, social contacts, perceived burden, emotional status, and role limitations due to emotional problems and the CR's psychological aggression and physical assault behaviors. The combination of CR's physical assault and psychological aggression provided the best sensitivity (75.4%) and specificity (70.6%) for elder mistreatment as defined by the expert panel. This finding has potential to be useful as a clinical screen for detecting mistreatment. CONCLUSIONS: The findings suggest important characteristics of older adults with dementia and their CGs that have potential for use in a clinical screening tool for elder mistreatment. Potential screening questions to be asked of CGs of people with dementia are suggested. [source]

Infection probability score, APACHE II and KARNOFSKY scoring systems as predictors of infection onset in haematology,oncology patients

Eleni Apostolopolou
Aim., To assess the predictive power of three systems: Infection Probability Score, APACHE II and KARNOFSKY score to the onset of healthcare-associated infections in haematology,oncology patients. Background., The high incidence of healthcare-associated infections is a frequent problem in haematology,oncology patients that affects morbidity and mortality of these patients. Design., A retrospective surveillance survey. Method., The survey was conducted for seven months in the haematology unit of a general hospital in Greece to assess the predictive power of Infection Probability Score, APACHE II and KARNOFSKY score to the onset of healthcare-associated infections. The sample consisted of 102 hospitalised patients. The diagnosis of healthcare-associated infections was based on the definitions proposed by CDC. Results., Among the participants, 53 (52%) were males and 49 (48%) were females with a mean age of 53·30 (SD 18·59) years old (range, 17,85 years). The incidence density of healthcare-associated infections (the number of new cases of healthcare-associated infections per 1000 patient-days) was 21·8 infections per 1000 patient-days. Among the 102 patients, healthcare-associated infections occurred in 32 (31·4%) patients who had a total of 48 healthcare-associated infections (47·5%). Among the 38 patients with neutropenia, 26 (68·4%) had more than one healthcare-associated infection. Of the 48 detected healthcare-associated infections, the most frequent type was blood-stream infection (n = 17, 35·4%), followed by Clostridium difficile infection (n = 11, 22·9%) and respiratory tract infection (n = 8, 3·4%). The best cut-off value of Infection Probability Score (IPS) for the prediction of a healthcare-associated infection was 10 with sensitivity of 59·4% and specificity of 74·3%. Conclusions., Between the three different prognostic scoring systems, IPS had the best sensitivity in predicting healthcare-associated infections. Relevance to clinical practice., IPS is an effective tool and should be used from nurses for the early detection of haematology,oncology patients who are susceptible to the onset of a healthcare-associated infection. [source]

RIFLE classification as predictive factor of mortality in patients with cirrhosis admitted to intensive care unit

Evangelos Cholongitas
Abstract Background and Aim:, To evaluate the association of the Risk, Injury, Failure, Loss and End-stage renal failure (RIFLE) score on mortality in patients with decompensated cirrhosis admitted to intensive care unit (ICU). Methods:, A cohort of 412 patients with cirrhosis consecutively admitted to ICU was classified according to the RIFLE score. Multivariable logistic regression analysis was used to evaluate the factors associated with mortality. Liver-specific, Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA) and RIFLE scores on admission, were compared by receiver,operator characteristic curves. Results:, The overall mortality during ICU stay or within 6 weeks after discharge from ICU was 61.2%, but decreased over time (76% during first interval, 1989,1992 vs 50% during the last, 2005,2006, P < 0.001). Multivariate analysis showed that RIFLE score (odds ratio: 2.1, P < 0.001) was an independent factor significantly associated with mortality. Although SOFA had the best discrimination (area under receiver,operator characteristic curve = 0.84), and the APACHE II had the best calibration, the RIFLE score had the best sensitivity (90%) to predict death in patients during follow up. Conclusions:, RIFLE score was significantly associated with mortality, confirming the importance of renal failure in this large cohort of patients with cirrhosis admitted to ICU, but it is less useful than other scores. [source]

Des-,-carboxyprothrombin, ,-fetoprotein and AFP-L3 in patients with chronic hepatitis, cirrhosis and hepatocellular carcinoma

Francisco A Durazo
Abstract Background and Aim:, Hepatocellular carcinoma (HCC) is a common complication in patients with chronic viral hepatitis. Detection of HCC at an early stage is critical for a favorable clinical outcome. The study aim was to: (i) compare the levels of des-,-carboxyprothrombin (DCP), ,-fetoprotein (AFP) and AFP-L3 in HCC patients and in chronic viral hepatitis patients without HCC; (ii) define the level of each tumor marker with the best sensitivity and specificity for HCC diagnosis; and (iii) to correlate the levels of these markers with respect to size and tumor burden. Methods:, Two hundred and forty patients with either hepatitis B virus (HBV) or hepatitis C virus (HCV) infection were studied. These included 144 with HCC, 47 with chronic hepatitis (fibrosis stage I,III on liver biopsy) and 49 with cirrhosis. Results:, Levels of DCP, AFP and AFP L-3 were significantly higher in patients with HCC than in those without HCC (P , 0.0001). Receiver,operating curves (ROC) indicated that the cut-off value with the best sensitivity and specificity for each test was ,84 mAU/mL for DCP, ,25 ng/mL for AFP and ,10% for AFP-L3. The sensitivity, specificity and positive predictive value (PPV) for DCP was 87%, 85% and 86.8%, for AFP 69%, 87% and 69.8%, and for AFP-L3 56%, 90% and 56.1%, respectively. DCP levels were below the ROC cut-off in all patients without HCC. In patients with single lesions, there was a direct correlation of DCP to tumor size. High levels of AFP correlated with diffuse type of HCC. All three markers were significantly elevated in the presence of metastatic HCC. No advantage was observed by combining two or three markers for HCC diagnosis. Conclusion:, DCP had the highest sensitivity and PPV for HCC diagnosis, had a direct correlation with tumor size, and was not elevated in any patients without HCC. DCP should be used as the main serum test for HCC detection. [source]

Development and validation of a liquid chromatographic/tandem mass spectrometric assay for the quantitation of nucleoside HIV reverse transcriptase inhibitors in biological matrices

Séverine Compain
Abstract Besides liquid chromatographic (LC)/UV methods adapted to therapeutic drug monitoring, there is still a need for more powerful techniques that can be used for pharmacological research and clinical purposes. We developed an LC method coupled with tandem mass spectrometry (MS/MS) to separate, detect and quantify with high sensitivity the nucleoside analogues used in multitherapies (zidovudine, stavudine, zalcitabine, didanosine, lamivudine and abacavir) in plasma and in the intracellular medium. We worked on two essential issues: (i) the need to use two ionization modes in order to achieve the best sensitivity, which leads to the optimization of the chromatographic separation of drugs detected in the positive ionization mode and drugs detected in the negative ionization mode, and (ii) the need to optimize the extraction step in order to enhance sample recovery. The peripheral blood mononuclear cells were lysed in Tris buffer,MeOH. A clean-up procedure was performed by solid-phase extraction only for plasma samples. The LC separation was carried out on a Zorbax Stable Bond C18 column followed by MS/MS analysis after electrospray ionization in either the negative or positive mode. The positive ionization mode was applied at the beginning of the run to detect zalcitabine and lamivudine, then the ionization mode was changed to negative for the detection of didanosine, stavudine, internal standard and zidovudine. The calibration range for all the analytes was 0.5,200 ng ml,1. The recoveries were between 64 and 90%, with coefficients of variation (CVs) lower than 15%. The inaccuracy (bias) was ±15% with CVs always lower than 12%. The analytes were stable at room temperature and in the extraction solvent for at least 24 h, after storage at ,80 °C for 3 months, after three freeze,thaw cycles and in the injection solvent after 48 h at 4 °C. Together with the measurement of intracellular triphosphorylated metabolites thanks to the powerful plasma and intracellular assay method for intact drugs, it is possible to describe the behaviour of nucleoside analogues against HIV through plasma pharmacokinetics, cell membrane diffusion including drug transport involvement, and also the intracellular metabolism. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Ethyl Glucuronide in Hair Compared With Traditional Alcohol Biomarkers,A Pilot Study of Heavy Drinkers Referred to an Alcohol Detoxification Unit

ALCOHOLISM, Issue 5 2009
Gudrun Hřiseth
Background:, Traditional biomarkers for heavy alcohol use include serum carbohydrate-deficient transferrin (CDT), the enzymes aspartate aminotranserase (AST), and alanine aminotransferase (ALT) as well as gamma-glutamyl transferase (GGT). Measurement of the nonoxidative ethanol metabolite, ethyl glucuronide (EtG) in hair, has been proposed as a new marker with superior qualities. The aim of this study was to investigate the sensitivity of EtG in hair to detect heavy alcohol use compared with CDT, AST, ALT, and GGT. We also wanted to study the quantitative relation between alcohol intake and the different biomarkers. Methods:, Sixteen patients with a history of heavy alcohol use over the previous 3 months were recruited directly after admission to a withdrawal clinic. They were thoroughly interviewed about their drinking pattern as well as relevant diseases and use of medicines or drugs. Serum was sampled and analyzed for %CDT, AST, ALT, and GGT. Hair samples were collected and analyzed for EtG. Results:, The mean estimated daily intake (EDI) over the previous 3 months was 206 ± 136 g pure alcohol. All patients fulfilled the criteria for heavy alcohol use. The sensitivity to detect heavy alcohol use was 64% for %CDT, 67% for AST, 67% for ALT, 93% for GGT, and 94% for EtG. There was no correlation between the quantitative values of EDI and %CDT, AST, ALT, and GGT. There was a positive, statistically significant correlation between EDI and the level of EtG in hair. Conclusions:, In this study, EtG in hair and GGT showed the best sensitivity to detect heavy alcohol use and there was a positive correlation between EDI and the concentrations of EtG in hair. Before giving recommendations for clinical practice, further studies should be carried out on larger materials and populations with a wider range of alcohol intake. [source]

A method for selecting and monitoring medication sales for surveillance of gastroenteritis,

Camille Pelat
Abstract Purpose Monitoring appropriate categories of medication sales can provide early warning of certain disease outbreaks. This paper presents a methodology for choosing and monitoring medication sales relevant for the surveillance of gastroenteritis and assesses the operational characteristics of the selected medications for early warning. Methods Acute diarrhoea incidences in mainland France were obtained from the Sentinelles network surveillance system for the period 2000,2009. Medication sales grouped by therapeutic classes were obtained on the same period. Hierarchical clustering was used to select therapeutic classes correlating with disease incidence over the period. Alert thresholds were defined for the selected therapeutic classes. Single and multiple voter algorithms were investigated for outbreak detection based on sales crossing the thresholds. Sensitivity and specificity were calculated respective to known outbreaks periods. Results Four therapeutic classes were found to cluster with acute diarrhoea incidence. The therapeutic class other antiemetic and antinauseants had the best sensitivity (100%) and timeliness (1.625 weeks before official alerts), for a false alarm rate of 5%. Multiple voter algorithm was the most efficient with the rule: ,Emit an outbreak alert when at least three therapeutic classes are over their threshold' (sensitivity 100%, specificity 95%, timeliness 1.750 weeks before official alerts). Conclusions The presented method allowed selection of relevant therapeutic classes for surveillance of a specific condition. Multiple voter algorithm based on several therapeutic classes performed slightly better than the best therapeutic class alone, while improving robustness against abrupt changes occurring in a single therapeutic class. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Analysis of native and chemically modified oligonucleotides by tandem ion-pair reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry

Kenneth J. Fountain
Ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC) was utilized in tandem with negative-ion electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) for the analysis of native and chemically modified oligonucleotides. Separation was performed on a 1.0,×,50,mm column packed with porous C18 sorbent with a particle size of 2.5,,m and an average pore diameter of 140 Ĺ. A method was developed which maximizes both chromatographic separation and mass spectrometric sensitivity using an optimized buffer system containing triethylamine and 1,1,1,3,3,3-hexafluoro-2-propanol with a methanol gradient. The ESI-TOFMS tuning parameters were also optimized in order to minimize in-source fragmentation and achieve the best sensitivity. Analyses of native, phosphorothioate, and guanine-rich oligonucleotides were performed by LC/MS. Detection limits were at sub-picomole levels with an average mass accuracy of 125,ppm. The described method allowed for the LC/MS analysis of oligonucleotides up to 110mer in length with little alkali cation adduction. Since sensitive detection of oligonucleotides was achieved with ultraviolet (UV) detection, we utilized a combination of UV-MS for quantitation (UV) and characterization (MS) of oligonucleotides and their failure sequence fragments/metabolites. Copyright © 2003 John Wiley & Sons, Ltd. [source]

A comparison of auditory brainstem responses and behavioral estimates of hearing sensitivity in Lemur catta and Nycticebus coucang

Marissa A. Ramsier
Abstract Primates depend on acoustic signals and cues to avoid predators, locate food, and share information. Accordingly, the structure and function of acoustic stimuli have long been emphasized in studies of primate behavioral and cognitive ecology. Yet, few studies have addressed how well primates hear such stimuli; indeed, the auditory thresholds of most primate species are unknown. This empirical void is due in part to the logistic and economic challenges attendant on traditional behavioral testing methods. Technological advances have produced a safe and cost-effective alternative,the auditory brainstem response (ABR) method, which can be utilized in field conditions, on virtually any animal species, and without subject training. Here we used the ABR and four methods of threshold determination to construct audiograms for two strepsirrhine primates: the ring-tailed lemur (Lemur catta) and slow loris (Nycticebus coucang). Next, to verify the general efficacy of the ABR method, we compared our results to published behaviorally-derived audiograms. We found that the four ABR threshold detection methods produced similar results, including relatively elevated thresholds but similarly shaped audiograms compared to those derived behaviorally. The ABR and behavioral absolute thresholds were significantly correlated, and the frequencies of best sensitivity and high-frequency limits were comparable. However, at frequencies ,2,kHz, ABR thresholds were especially elevated, resulting in decreased agreement with behavioral thresholds and, in Lemur, the ABR 10-dB range starting points were more than 2 octaves higher than the behavioral points. Finally, a comparison of ABR- and behaviorally-derived audiograms from various animal taxa demonstrates the widespread efficacy of the ABR for estimating frequency of best sensitivity, but otherwise suggests caution; factors such as stimulus properties and threshold definition affect results. We conclude that the ABR method is a promising technique for estimating primate hearing sensitivity, but that additional data are required to explore its efficacy for estimating low-frequency thresholds. Am. J. Primatol. 72:217,233, 2010. © 2009 Wiley-Liss, Inc. [source]

Macrophage activation syndrome in juvenile systemic lupus erythematosus: A multinational multicenter study of thirty-eight patients

Alessandro Parodi
Objective To describe the clinical and laboratory features of macrophage activation syndrome as a complication of juvenile systemic lupus erythematosus (SLE). Methods Cases of juvenile SLE,associated macrophage activation syndrome were provided by investigators belonging to 3 pediatric rheumatology networks or were found in the literature. Patients who had evidence of macrophage hemophagocytosis on bone marrow aspiration were considered to have definite macrophage activation syndrome, and those who did not have such evidence were considered to have probable macrophage activation syndrome. Clinical and laboratory findings in patients with macrophage activation syndrome were contrasted with those of 2 control groups composed of patients with active juvenile SLE without macrophage activation syndrome. The ability of each feature to discriminate macrophage activation syndrome from active disease was evaluated by calculating sensitivity, specificity, and area under the receiver operating characteristic curve. Results The study included 38 patients (20 with definite macrophage activation syndrome and 18 with probable macrophage activation syndrome). Patients with definite and probable macrophage activation syndrome were comparable with regard to all clinical and laboratory features of the syndrome, except for a greater frequency of lymphadenopathy, leukopenia, and thrombocytopenia in patients with definite macrophage activation syndrome. Overall, clinical features had better specificity than sensitivity, except for fever, which was highly sensitive but had low specificity. Among laboratory features, the best sensitivity and specificity was achieved using hyperferritinemia, followed by increased levels of lactate dehydrogenase, hypertriglyceridemia, and hypofibrinogenemia. Based on the results of statistical analysis, preliminary diagnostic guidelines for macrophage activation syndrome in juvenile SLE were developed. Conclusion Our findings indicate that the occurrence of unexplained fever and cytopenia, when associated with hyperferritinemia, in a patient with juvenile SLE should raise the suspicion of macrophage activation syndrome. We propose preliminary guidelines for this syndrome in juvenile SLE to facilitate timely diagnosis and correct classification of patients. [source]