Kit Users Research Articles

Commercial ELISA Measurement of Allergens and Gluten: What We Can Learn from Case Studies.

During the last decade, results from ELISA test kits have often been criticized as being flawed. Therefore, it may appear counterintuitive that ELISAs are used for most food allergen and gluten analytical needs. One reason, in addition to the nonavailability of comparable alternative methods, is the fact that the methods used underwent a long validation and learning period in the market. This publication presents several case studies on interference, cross-reactivity issues, calibrators, fragmented allergens and gluten, matrix influences, and misunderstood intended-use statements. Afterward, the relevant validation parameter LOD, LOQ, selectivity, and precision are discussed. Finally, a comprehensive list of practical recommendations for ELISA test kit users is presented.

Forensic evaluation of 27 y-str haplotypes in a population sample from nigeria

Nigeria is a country located in Gulf of Guinea, in West Africa, facing the Atlantic Ocean. It is one of the most populous country in the world. There are more than 500 ethnic groups inhabiting the territory, representing a high diversity of languages and cultures. In this study, we collected 142 samples from the three largest ethnic groups in Nigeria: Hausa, Igbo and Yoruba. These samples were typed for the 27 Y-STR loci included in the Yfiler® Plus kit. A total of 140 different haplotypes were found, with two haplotypes shared by 2 individuals. The haplotype diversity was 0.9998 (±0.0009), slightly higher than that obtained with the 17 Y-STRs from the Yfiler kit (0.9992±0.0010). The Yfiler kit also showed an increased number of shared haplotypes, with 4 being shared by 2 individuals and one by 3. The average gene diversity over loci was lower in Nigeria than in the U.S. population groups reported in Yfiler® Plus kit User Guide. The DYS391, DYS390, DYS438, DYS392, DYS437 and DYS533 showed low diversity values (GD≤0.35). Comparisons between Nigeria and five populations in East Africa, the only African data available for the Yfiler® Plus markers, revealed significant differences among all populations (p-values ≪0.00005). The smallest FST was found with Kenya (FST=0.025), followed by Ethiopia (FST=0.105). As expected, distances with Djibouti, Eritrea and Somalia were higher that 20%, since our sample are from Bantu speakers, not represented in these population sample.

Raman optical activity applied to biological systems

Introduction Raman Optical Activity (ROA) provides information about of chirality in molecules with high relevance for health area. In the present work, we implemented new technique to measure the ROA spectra of chiral molecules per Raman Spectroscopy by Ellipsometry (RaSE). ROA quantifies the small difference in the intensity of Raman scattering for chiral molecules in incidence of polarized circularly laser light and RaSE measures the Raman scattering by Stokes parameters, which describe the polarization state of light. Purpose Study of L. infantum parasite the etiological agent of Visceral Leishmaniasis by RaSE technique. Materials and methods DNA sample of L. infantum was extracted of a crop from parasite in the promastigote phase in according to the manual procedure of extraction kit user NucleoSpin® Tissue – Genomic DNA from Tissue, Chapter. 5: Standard protocol for human or animal tissue and cultured cells. This procedure provided us a DNA concentration S = 17,5 ng/μL and V = 50 μL. RaSE spectra were obtained as excitation light linear in polarization set up that can be decomposed in two circular polarization to obtain Stokes parameters that describes the signal ROA. Results Raman spectra showed vibration bands in the range of 400–1700 cm−1 corresponding to DNA constituents. S3 Stokes parameter indicated a chirality preponderance of LCP light over RCP light. Conclusion Raman spectra assigned vibration mode of DNA and indicated a chirality preponderance. We will study L. infantum by RaSE-ROA in order to obtain information on the structure that is lost with the use of other techniques.

Factors associated with use and non-use of the Fecal Immunochemical Test (FIT) kit for Colorectal Cancer Screening in Response to a 2012 outreach screening program: a survey study

BackgroundThe one-sample fecal immunochemical test (FIT) is gaining popularity for colorectal cancer (CRC) screening of average-risk people. However, uptake and annual use remain suboptimal.MethodsIn 2013, we mailed questionnaires to three groups of nonHispanic White, Black, and Latino Kaiser Permanente Northern California (KPNC) members ages 52–76 who received FIT kits in 2010–2012: Continuers did the FIT all 3 years; Converts in 2012, but not 2010 or 2011; and Nonusers in none of the 3 years. The questionnaires covered social influences, perceived CRC risk, reasons for using (Continuers, Converts) or avoiding using (Nonusers) the FIT, and recommendations for improving the kit.ResultsContinuers (n = 607, response rate 67.5 %), Converts (n = 317, response rate 35.6 %), and Nonusers (n = 215, response rate 21.1 %) did not differ in perceived risk or family history of CRC, but Nonusers were less likely than Continuers and Converts to know someone who had polyps or CRC. Continuers, Converts, and Nonusers did not differ in social network encouragement of CRC screening, but did differ in believing that it was very important that they be screened (88.3 %, 68.4 %, 47.7 %) and that their medical team thought it very important that they be screened (88.6 %, 79.9 %, 53.9 %). Approximately half of Continuers and Converts completed the FIT to please their doctor. Converts were less likely than Continuers to use the FIT to “make sure they were OK” (53.7 % vs. 72.6 %) or “protect their health” (46.1 % vs. 76.4 %). Nearly half of Converts completed the FIT out of guilt. Approximately half of FIT kit users suggested adding a disposable glove, extra paper, and wider-mouth tube to the kit. Nonusers’ reasons for not using the FIT included discomfort, disgust, or embarrassment (59.6 %); thinking it unnecessary (32.9 %); fatalism/fear (15.5 %); and thinking it too difficult to use (14.5 %), but <10 % did not want CRC screening at all.ConclusionsNonusers and irregular users of the FIT are less intrinsically motivated to get CRC screening than long-term users and more averse to preparing their stool sample. Changes to the FIT kit to address discomfort and difficulty factors might improve uptake and continued use.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-1908-x) contains supplementary material, which is available to authorized users.

Determination of 21-hydroxylase autoantibodies: inter-laboratory concordance in the Euradrenal International Serum Exchange Program.

21-Hydroxylase autoantibodies (21OHAb) are markers of an adrenal autoimmune process that identifies individuals with autoimmune Addison's disease (AAD). Quality and inter-laboratory agreement of various 21OHAb tests are incompletely known. The objective of the study was to determine inter-laboratory concordance for 21OHAb determinations. Sixty-nine sera from 51 patients with AAD and 51 sera from 51 healthy subjects were blindly coded by a randomization center and distributed to 14 laboratories that determined 21OHAb, either by an "in-house" assay (n=9) using in vitro-translated (35)S-21OH or luciferase-labeled 21OH or a commercial kit with (125)I-21OH (n=5). Main outcome measures were diagnostic accuracy of each participating laboratory and inter-laboratory agreement of 21OHAb assays. Intra-assay coefficient of variation ranged from 2.6% to 5.3% for laboratories using the commercial kit and from 5.1% to 23% for laboratories using "in-house" assays. Diagnostic accuracy, expressed as area under ROC curve (AUC), varied from 0.625 to 0.947 with the commercial kit and from 0.562 to 0.978 with "in-house" methods. Cohen's κ of inter-rater agreement was 0.603 among all 14 laboratories, 0.691 among "in-house" laboratories, and 0.502 among commercial kit users. Optimized cutoff levels, calculated on the basis of AUCs, increased the diagnostic accuracy of every laboratory (AUC >0.9 for 11/14 laboratories) and increased the Cohen's κ of inter-rater agreement. Discrepancies in quantitation of 21OHAb levels among different laboratories increased with increasing autoantibody levels. The quality of 21OHAb analytical procedures is mainly influenced by selection of cutoff value and correct handling of assay materials. A standardization program is needed to identify common standard sera and common measuring units.

The FluidEarth 2 implementation of OpenMI 2.0

Following the release of the OpenMI 2.0 standard for model coupling with reference object classes (interfaces) in C# and Java, a set of tools including a Software Development Kit (SDK) and Graphical User Interface (GUI) is expected to accompany it. These are necessary to enable numerical model developers to easily adapt their models to become OpenMI compliant and to allow modellers to easily assemble and run compositions of them. FluidEarth 2 is an HR Wallingford initiative providing these open source tools for the .net 4.0 Framework together with training, community support and sample models. They are the only such open source tools available so in this sense they act as the reference SDK and GUI for OpenMI 2.0 with .net. The purpose of this paper is to outline these and demonstrate a set of examples. A series of components were successfully constructed and compositions built. These include training models designed to demonstrate different aspects of model coupling, moving to industry strength model codes simulating dam-break bathymetry updates. The FluidEarth 2 tools have been designed to be cross-platform and have been tested under Windows and Linux (using Mono). Usage is successfully demonstrated, providing an environment for integrated modelling with OpenMI 2.0.

Prevalence and Factors Associated With Trichomonas vaginalis Infection Among High-Risk Women in Los Angeles

Remnant specimen from 1215 women screening for chlamydia/gonorrhea at 4 different venue types (sexually transmitted disease clinics, home-test kit users, juvenile and adult detention) in Los Angeles, California, were tested for Trichomonas vaginalis. Prevalence of T. vaginalis varied by screening population, and concurrent chlamydia or gonorrhea was independently associated with T. vaginalis.

Differential Use of Elementary Science Kits

The use of kits in elementary science classes is a growing trend in some countries. Kits provide materials and inquiry lessons in a ready-to-teach format for teachers to use in their science instruction. This study examined elementary teachers' instructional strategies, classroom practices, and assessment types in relation to the frequency of science kit use. A total of 503 elementary teachers from an urban school district received professional development, implemented kits in their classrooms for a year, and then completed a survey about science kit use and teaching practices. Despite similarities in demographic characteristics (gender, ethnicity, certification/educational level), there were significant differences in teachers' use of inquiry-based teaching and assessment practices by kit use. Teachers who reported using kits the most often were significantly more likely to report that their students designed and implemented laboratory investigations as well recorded, represented, and analyzed data. In addition, the high kit users indicated that they were more likely to use student groups, require students to use evidence to support claims, and use alternative assessments of student work including portfolios, notebooks, and long-term projects than those teachers who used kits less frequently. Those teachers who reported using kits the least often were significantly more likely to report having students practice for standardized tests. The role of kits in promoting reform-based teaching practices is discussed.

Performance of succinylacetone assays and their associated proficiency testing outcomes

BackgroundSuccinylacetone (SUAC) is the primary metabolic marker for hepatorenal tyrosinemia. Materials and methodsWe used results reported for dried-blood-spot proficiency testing (PT) specimens and hepatorenal tyrosinemia patients' newborn screening (NBS) samples to demonstrate analytic biases in SUAC recoveries and differences in presumptive clinical classifications. ResultsSUAC recoveries from non-kit and NeoBase™ kit tandem mass spectrometry methods were markedly different. Kit users that set high cutoff values submitted discordant clinical assessments of “within normal limits” for PT specimens enriched with 10–15μmol SUAC/L in blood. SUAC levels in tyrosinemia patients' NBS samples analyzed by NeoBase™ kit were lower than those in samples analyzed by non-kit methods. ConclusionsFrom 2009 to 2011, analytic biases in SUAC recoveries were consistent. Discordant clinical assessments of PT specimens were associated with high cutoff values for NeoBase™ kit results. Method-related differences in SUAC concentrations of tyrosinemia patients' samples were consistent with those of PT specimens.

Extraction of differential expressing aphid-resistance genes of sorghum (Sorghum bicolor L. Monech) and construction of suppression subtractive hybridization (SSH) library

Experiments were conducted for the extraction of differential expressing aphid-resistance genes of sorghum ( Sorghum bicolor L. Monech) in the experimental laboratories and fields of Hebei Agricultural University, China and Shenyang Agricultural University, Liaoning Province, China, during 2010 to 2011 and suppression subtractive hybridization (SSH) library was constructed. The seeds of two sorghum varieties (Henong-16 and Qian-3) were grown and aphids were infested through natural and artificial way on sorghum seedlings (10-day old) with a paint brush. Total mRNA was isolated from fresh leaves samples using Trizol reagent and plant RNA mate (TAKARA). Integrity of RNA was confirmed by 1.2% agarose gel electrophoresis. SSH was performed using PCR-Select cDNA subtraction kit user manual according to the manufacturer’s instruction (Clontech Laboratories, Inc, USA). cDNA that contained specific (differentially expressed) transcripts were denoted as tester and the reference cDNA as driver. Tester and driver cDNAs were hybridized after two rounds of subtractive suppression PCR and the pMD18-T vector (TAKARA, Dalian, China). After preliminary screening by subtractive hybridization, plasmid restriction enzyme digestion, colony PCR for 100 forward and 100 reverse clones were sequenced by two-way hybridization using Mega BACE1000 to obtain better quality of 200 expressed sequence tag (EST) sequences. Cross-match software and ClustalW2 were used to obtain vector sequence shielding and multiple comparisons. Using BLAST at NCBI database for homology comparisons, it was concluded that a number of EST sequences which had different degrees of homology with known proteins or genes and another six EST sequences did not have any significant homology in the database. These sequences might have representation for new and unknown genes, or higher variability of non-coding region cDNA sequences. Key words : Extraction, sorghum, SSH, aphid-resistance genes.

Focus on lasers and imaging

Focus on lasers and imaging

The ability of two commercially available quick test kits to detect drug‐facilitated sexual assault drugs in beverages

Assessment of the sensitivity and specificity of two commercially available 'drug-facilitated sexual assault' drug detector kits, Drink Guard and Drink Detective. Experimental. Laboratory. Gamma hydroxybutyrate (GHB) sodium salt, ketamine hydrochloride, temazepam, flunitrazepam and diazepam were dissolved (Tween added to benzodiazepine solutions) as separate stock solutions and added to 330 ml samples of cola (Pepsi Max), beer (Stella Artois), 'alcopop' (Bacardi Breezer) and placebo (distilled water). The doses used are reported to be common in cases of intoxication. Each kit was tested 10 times for each drink/drug combination. Two blind, independent observers scored each test (presence/absence of drug) in accordance with kit instructions; chi 2 was used to compare the proportion of times raters scored tests correctly and incorrectly. Sensitivity and specificity were calculated overall, for each drink, and sensitivity was calculated for each drug. Inter-observer agreement was evaluated using the kappa statistic. While both raters were able to score significantly more tests correctly than incorrectly using Drink Detective, and one rater scored similarly using Drink Guard, the overall sensitivity of Drink Detective and Drink Guard was 69.0% (95% CI 64.2-73.5%) and 37.5% (95% CI 30.1-45.5%), respectively. Sensitivity was drink-dependent. Drink Detective was unable to detect our dose of GHB in water, with all tests scored negatively by both raters for this drink/drug combination (n = 20 negative scores). Overall, specificity was 76.6% (95% CI 71.5-81.0%) and 87.9% (95% CI 83.0-91.6%) for Drink Guard and Drink Detective, respectively, but was affected by the beverage. Inter-rater agreement was poor for Drink Guard (kappa = 0.278 +/- 0.069) but excellent for Drink Detective (kappa = 0.894 +/- 0.245). Inter-observer agreement was drug-dependent. Use of drug detector kits by the public in the night-time environment needs further investigation and may create a false sense of security (false negatives) and undue concern (false positives) among kit users.

Generalized P2P Collaborative Technique for Multimedia based CBT

The CBT based E-learning is a passive learning. The user is simply an observer. To make the learning process live, the active participation of the student is necessary. The collaborative learning is very effective solution to this problem. But the CBT kit users are geographically scattered. The collaborative learning of these students was an impossible task. The Internet and Peer to Peer network based collaborative tools shows the ray of hope. This paper describes the collaborative learning technique for such geographically scattered CBT kit users.The work has been done in four parts and took around 6 years. In the forth part, the P2P & Client-Server (hybrid) technology based Collaborative tool, namely Groove Workspace, has been used to create collaborative environment for geographically scattered CBT kit users.When applied, this technique has provided natural collaborative cost effective environment and produces very encouraging results at the cost of little extra time. For measuring the overall effect, the technique has been tested on four batches of students. This is a generalized technique and can be used to provide the collaborative environment to multimedia based CBT of the any subject of any discipline.

Home collection kits for HIV testing: evaluation of three strategies for dealing with insufficient dried blood specimens.

Home collection kits allow individuals to obtain a blood specimen at home and send it to a laboratory for HIV testing. In preliminary studies, 15% of kit users submitted specimens considered to be insufficient for analysis. The current Public Health Service policy requires the laboratory to reject all such specimens entirely and request a second specimen, even though some specimens are sufficient to perform an enzyme immunoassay (EIA) but not a Western blot (WB) test. Using decision analysis, we evaluated three strategies to handle specimens sufficient to perform an EIA but insufficient to perform a WB analysis: current recommendation, or baseline, for which no test is preformed and "quantity not sufficient" is reported; alternative 1 , for which an EIA is done and reported as "negative" or "quantity not sufficient" (if initially reactive); and alternative 2, for which an EIA is done and reported as "negative" or "a reactive screening test" (if initially reactive). Baseline strategy requires all consumers with an initial specimen sufficient for EIA only to submit a second specimen, but either alternative requires fewer than 3% to submit a second specimen. Although 80% of consumers with an initial specimen sufficient for EIA learn their test results only with the baseline strategy, more than 99% learn their test results with either alternative. With the scenario of high (2%) HIV prevalence, 91% of consumers who would be told "reactive screening test" are truly infected. At a low (0.1%) HIV prevalence, 33% of consumers who would be told "reactive screening test" are truly infected. When a specimen is sufficient for EIA only, it is preferable to perform the EIA instead of rejecting the specimen, because many persons can get results from the initial specimen and because many fewer are required to submit a second specimen. Current policy should be reexamined in light of these findings.