Development and validation of dry reagent time-resolved fluoroimmuno assays for zeranol and alpha-zearalenol to assist in distinguishing zeranol abuse from Fusarium spp. toxin contamination in bovine urine

Zeranol, an oestrogenic growth promoter in food animals, is banned within the European Union (EU). However, commercially available immunoassay kits for zeranol cross-react with toxins formed by naturally occurring Fusarium spp. fungi, leading to false-positive screening results. This paper describes the validation of a specificity enhanced, rapid dry reagent time-resolved fluoroimmunoassay (TR-FIA) for zeranol (recovery 99%, limit of detection 1.3 ng ml(-1)) demonstrating that up to 150 ng ml(-1) of Fusarium spp. toxins in urine do not lead to false-positive results. This assay will assist EU Member States to implement Council Directive 961 23\EC, which requires states to monitor for potential abuses of zeranol. A similar TR-FIA for the Fusarium spp. toxin a-zearalenol, using the same sample extract, is also described (recovery 68%, limit of detection 5.6 ng ml(-1)). Only the addition of diluted sample extract is required to perform these dry-reagent TR-FIAs, the results being available within 1 h of extract application. The EU-funded project 'Natural Zeranol' (FAIR5-CT97-3443) will use these fluoroimmunoassays to screen bovine urine in four Member States to gather data on the seasonality of Fusarium spp. toxin contamination of urine and the incidence of zeranol screening test positives.

Detection of unwanted residues of ivermectin in bovine milk by dissociation-enhanced lanthanide fluoroimmunoassay

Avermectins are frequently used to control parasitic infestations in many animal species. Previous studies have shown the long-term persistence of unwanted residues of these drugs in animal tissues and fluids. An immunoassay screening test for the detection acid quantification of ivermectin residues in bovine milk has been developed. After an extensive extraction procedure, milk samples were applied to a competitive dissociation-enhanced lanthanide fluoroimmunoassay using a monoclonal antibody against an ivermectin-transferrin conjugate, The monoclonal antibody, raised in Balb C mice, showed cross-reactivity with eprinomectin (92%), abamectin (82%) and doramectin (16%). The limit of detection of the assay (mean + 3 SD), calculated from the analysis of 17 known negative samples, was calculated as 4.6 ng/mL. Intra- and inter-assay RSDs were determined as 11.6% and 15.8%, respectively, using a negative bovine milk sample fortified with 25 ng/mL ivermectin. Six Friesian milking cows were treated with ivermectin, three with a pour-on formulation of the drug and three with an injectable solution at the manufacturer's recommended dose rate. An initial mean peak in ivermectin residue concentration was detected at day 4 (mean level = 47.5 ng/mL) and day 5 post-treatment (mean level = 26.4 ng/mL) with the injectable form and pour-on treatment, respectively. A second peak in residue concentration was observed using the DELFIA(R) procedure 28 days post-treatment in both treatment groups (23.1 ng/mL injectable and 51.9 ng/mL pour-on). These second peaks were not confirmed by HPLC and must at this Lime be considered to be false-positive results. By day 35 after treatment the mean ivermectin residue concentration of both groups fell below the limit of detection of the assay. Copyright (C) 2000 John Wiley & Sons, Ltd.

Rapid serological diagnosis of Helicobacter pylori:a need for caution and re-evaluation

Screening for Helicobacter pylori in dyspeptic patients may improve selectivity for gastroscopy. Rapid serological tests based on ELISA technique are cheap, readily available and simple to use in the clinical setting. However local evaluation is essential in order to validate these techniques. Fifty-six dyspeptic patients (aged less than 45 yr) had a rapid serological test (Helisal) performed prior to gastroscopy. At gastroscopy H. pylori status was assessed using culture and histology. The Helisal sensitivity was 80 per cent, specificity 82 per cent. Screening patients with the Helisal test would have missed 6 patients with peptic ulcer disease and 2 with oesophagitis. The Helisal test did not perform satisfactorily as a screening test in selection of patients for gastroscopy.

Gliadin antibody detection in gluten enteropathy

Circulating antigliadin antibody has been described in patients with gluten enteropathy although the prevalence varies in different studies. It has been suggested that the investigation for antigliadin antibody might be useful as a screening test. The object of the present study was to evaluate two different techniques for assaying these antibodies - an indirect immunofluorescent method and an enzyme-linked immunosorbent assay (ELISA). Antibodies were assayed in the sera of 102 patients in whom jejunal biopsies were also obtained. The specificity of both tests was greater than 95%, and the correlation between the presence of antibody and histology was significant (p <0.005), though the sensitivity of each test was less than 70%.

Sensitivity and specificity of frequency-doubling technology, tendency-oriented perimetry, and Humphrey Swedish interactive threshold algorithm-fast perimetry in a glaucoma practice

PURPOSE: To evaluate the sensitivity and specificity of the screening mode of the Humphrey-Welch Allyn frequency-doubling technology (FDT), Octopus tendency-oriented perimetry (TOP), and the Humphrey Swedish Interactive Threshold Algorithm (SITA)-fast (HSF) in patients with glaucoma. DESIGN: A comparative consecutive case series. METHODS: This was a prospective study which took place in the glaucoma unit of an academic department of ophthalmology. One eye of 70 consecutive glaucoma patients and 28 age-matched normal subjects was studied. Eyes were examined with the program C-20 of FDT, G1-TOP, and 24-2 HSF in one visit and in random order. The gold standard for glaucoma was presence of a typical glaucomatous optic disk appearance on stereoscopic examination, which was judged by a glaucoma expert. The sensitivity and specificity, positive and negative predictive value, and receiver operating characteristic (ROC) curves of two algorithms for the FDT screening test, two algorithms for TOP, and three algorithms for HSF, as defined before the start of this study, were evaluated. The time required for each test was also analyzed. RESULTS: Values for area under the ROC curve ranged from 82.5%-93.9%. The largest area (93.9%) under the ROC curve was obtained with the FDT criteria, defining abnormality as presence of at least one abnormal location. Mean test time was 1.08 ± 0.28 minutes, 2.31 ± 0.28 minutes, and 4.14 ± 0.57 minutes for the FDT, TOP, and HSF, respectively. The difference in testing time was statistically significant (P <.0001). CONCLUSIONS: The C-20 FDT, G1-TOP, and 24-2 HSF appear to be useful tools to diagnose glaucoma. The test C-20 FDT and G1-TOP take approximately 1/4 and 1/2 of the time taken by 24 to 2 HSF. © 2002 by Elsevier Science Inc. All rights reserved.

Physician recommendation for invasive prenatal testing: the case of the 'precious baby'

Do clinicians manage pregnancies conceived by assisted reproductive technologies (ART) differently from spontaneous pregnancies?

Clinicians decisions about prenatal testing during pregnancy depend, at least partially, on the method of conception.

Research thus far has shown that patients decisions regarding prenatal screening are different in ART pregnancies compared with spontaneous ones, such that ART pregnancies may be considered more valuable or precious than pregnancies conceived without treatment.

In this cross-sectional study, preformed during the year 2011, 163 obstetricians and gynecologists in Israel completed an anonymous online questionnaire.

Clinicians were randomly assigned to read one of two versions of a vignette describing the case of a pregnant woman. The two versions differed only with regard to the method of conception (ART; n 78 versus spontaneous; n 85). Clinicians were asked to provide their recommendations regarding amniocentesis.

The response rate among all clinicians invited to complete the questionnaire was 16.7. Of the 85 clinicians presented with the spontaneous pregnancy scenario, 37 (43.5) recommended amniocentesis. In contrast, of the 78 clinicians presented with the ART pregnancy scenario, only 15 (19.2) recommended the test. Clinicians were 3.2 (95 confidence interval [CI]: 1.66.6) times more likely to recommend amniocentesis for a spontaneous pregnancy than for an ART pregnancy.

The study is limited by a low response rate, the relatively small sample and the hypothetical nature of the decision, as clinician recommendations may have differed in an actual clinical setting.

Our findings show that fertility history and use of ART may affect clinicians recommendations regarding amniocentesis following receipt of screening test results. This raises the question of how subjective factors influence clinicians decisions regarding other aspects of pregnancy management.

There was no funding source to this study. The authors declare no conflicts of interest.

Donor chimaerism is a strong indicator of disease free survival following bone marrow transplantation for chronic myeloid leukaemia

Although Chronic Myeloid Leukaemia (CML) can be treated successfully with allogeneic bone marrow transplantation (BMT), leukaemia relapse remains a significant clinical problem. Molecular monitoring of the post transplant marrow can be useful in predicting relapse particularly in CML patients where the Philadelphia chromosome or its molecular counterpart, the BCR-ABL fusion messenger RNA can be used as a leukaemia specific marker of minimal residual disease (MRD). We have investigated chimaerism (using polymerase chain reaction of short tandem repeat sequences (STR-PCR)) and MRD status (using reverse transcriptase PCR of the BCR-ABL fusion mRNA) in a serial fashion in 18 patients who were in clinical and haematological remission post allogeneic BMT for chronic phase CML. Eleven patients exhibited complete donor chimaerism with no evidence of minimal residual disease. Five patients had transient or low level stable MC. Late MC and MRD was observed in two patients who relapsed > 6 years after T cell depleted BMT for CML. Thus STR-PCR is an appropriate screening test in the post transplant setting for CML patients, but those patients exhibiting mixed haemopoietic chimaerism should also be monitored using a leukaemia specific sensitive molecular assay.

Night-to-night variation of pulse oximetry in children with sleep-disordered breathing

BACKGROUND: Sleep-disordered breathing is a common and serious feature of many paediatric conditions and is particularly a problem in children with Down syndrome. Overnight pulse oximetry is recommended as an initial screening test, but it is unclear how overnight oximetry results should be interpreted and how many nights should be recorded.

METHODS: This retrospective observational study evaluated night-to-night variation using statistical measures of repeatability for 214 children referred to a paediatric respiratory clinic, who required overnight oximetry measurements. This included 30 children with Down syndrome. We measured length of adequate trace, basal SpO2, number of desaturations (>4% SpO2 drop for >10 s) per hour ('adjusted index') and time with SpO2<90%. We classified oximetry traces into normal or abnormal based on physiology.

RESULTS: 132 out of 214 (62%) children had three technically adequate nights' oximetry, including 13 out of 30 (43%) children with Down syndrome. Intraclass correlation coefficient for adjusted index was 0.54 (95% CI 0.20 to 0.81) among children with Down syndrome and 0.88 (95% CI 0.84 to 0.91) for children with other diagnoses. Negative predictor value of a negative first night predicting two subsequent negative nights was 0.2 in children with Down syndrome and 0.55 in children with other diagnoses.

CONCLUSIONS: There is substantial night-to-night variation in overnight oximetry readings among children in all clinical groups undergoing overnight oximetry. This is a more pronounced problem in children with Down syndrome. Increasing the number of attempted nights' recording from one to three provides useful additional clinical information.

Repeated measures screening for down's syndrome

Objective To demonstrate the potential value of screening for Down's Syndrome using highly correlated repeated measures of serum markers taken in the first and second trimesters of pregnancy. Design A Monte Carlo simulation study. Population Detection rates and false positive rates relating to the maternal age distribution of England and Wales for the period 1996 to 1998 were obtained using marker distributions from the SURUSS study. Results Screening using first trimester nuchal translucency and repeated measures of uE3 and PAPP-A in the first and second trimester has an estimated false positive rate of 0.3% for an 85% detection rate. This should be compared with the integrated test with an estimated false positive rate of 1.2% for the same detection rate. Conclusionsâ?? The performance of repeated measures screening tests, and their acceptability to women, should be assessed in further prospective studies.

Contingent screening for down syndrome is an efficient alternative to non-disclosure sequential screening

Objective To present a first and second trimester Down syndrome screening strategy, whereby second-trimester marker determination is contingent on the first-trimester results. Unlike non-disclosure sequential screening (the Integrated test), which requires all women to have markers in both trimesters, this allows a large proportion of the women to complete screening in the first trimester. Methods Two first-trimester risk cut-offs defined three types of results: positive and referred for early diagnosis; negative with screening complete; and intermediate, needing second-trimester markers. Multivariate Gaussian modelling with Monte Carlo simulation was used to estimate the false-positive rate for a fixed 85% detection rate. The false-positive rate was evaluated for various early detection rates and early test completion rates. Model parameters were taken from the SURUSS trial. Results Completion of screening in the first trimester for 75% of women resulted in a 30% early detection rate and a 55% second trimester detected rate (net 85%) with a false-positive rate only 0.1% above that achievable by the Integrated test. The screen-positive rate was 0.1% in the first trimester and 4.7% for those continuing to be tested in the second trimester. If the early detection rate were to be increased to 45% or the early completion rate were to be increased to 80%, there would be a further 0.1% increase in the false-positive rate. Conclusion Contingent screening can achieve results comparable with the Integrated test but with earlier completion of screening for most women. Both strategies need to be evaluated in large-scale prospective studies particularly in relation to psychological impact and practicability.

Exploring the perspective of midwives involved in offering serum screening for Down's syndrome in Northern Ireland

Aims. To explore the perspective of midwives offering serum screening for Down’s syndrome.

Background. Previous literature has indicated that the offer and discussion of prenatal serum screening tests with women is complex, and health professionals may influence women’s decisions to accept or decline screening. Midwives are usually the key professional to offer serum screening for Down’s syndrome in the UK but their perspective is relatively neglected in the literature.

Design. An explorative qualitative interview study with 15 midwives employed in a maternity unit in Northern Ireland involved in offering prenatal screening to pregnant women. Data were collected from 1 July 2005–31 October 2005.

Methods. A focused ethnographic approach was used to explore the perspective of midwives.

Results. Midwives reported difficulty in explaining the test to women and felt unable to provide the necessary information to adequately inform women within their appointment time. The test offered (the triple test) and potential pathway of subsequent care, were identified as sources of professional and personal conflict by midwives. The expectation that midwives would provide a universal offer of Down’s syndrome serum screening but be unable to support women regarding termination of pregnancy also created dissonance.

Conclusions. The feasibility of proceeding with a universal serum screening programme for Down’s syndrome is questionable in countries which legally or culturally oppose termination of pregnancy. Professionals practising within environments such as this experience conflict in their role, which affects communication with women when discussing screening tests.

Relevance to clinical practice. As midwives are often, the primary health professional providing information to women, it is important that midwives are key participants in ongoing planning and discussions about screening policy to ensure programmes are implemented successfully.

Family communication, genetic testing and colonoscopy screening in hereditary non-polyposis colon cancer: a qualitative study

Objective: Genetic testing and colonoscopy is recommended for people with a strong history of colorectal cancer (CRC). However, families must communicate so that all members are aware of the risk. The study aimed to explore the factors influencing family communication about genetic risk and colonoscopy among people with a strong family history of CRC who attended a genetic clinic with a view to having a genetic test for hereditary non-polyposis colon cancer (HNPCC).

General practitioners' habits and knowledge in relation to the management of H. pylori-associated dyspepsia and their views about a locally available 13-carbon urea breath test

We report the results of general practitioners' views on Helicobacter pylori-associated dyspepsia and use of screening tests in the community. The use of office serology tests in screening is of concern as independent validation in specialist units has been disappointing.