Population‐based study on the seroprevalence of parvovirus B19 in Amsterdam

A study was undertaken to estimate the seroprevalence of parvovirus B19 infection in the general adult population of Amsterdam, The Netherlands. To our knowledge this is the first study testing parvovirus B19 in a random sample of the Dutch adult population. The study was a cross‐sectional survey, and the study sample was stratified by age and ethnicity, with deliberate oversampling of minority ethnic groups. Serum samples obtained from 1,323 residents in 2004 were tested for antibodies to parvovirus B19. Basic demographic data (gender, age, country of birth, and number of children) were also available. Sixty‐two percent of the participants were seropositive; corrected for the oversampling the estimated prevalence in the Amsterdam adult population was 61%. No specific predictors or risk groups for seropositivity were identified. In our urban adult study population no positive correlation with increasing neither age, nor significant differences between age groups were found. These results imply that almost 40% of the adult Amsterdam population is susceptible to infection. J. Med. Virol. 81:1305–1309, 2009. © 2009 Wiley‐Liss, Inc.     

Unambiguous test results or individual independence? The role of clients and families in predictive BRCA-testing in the Netherlands compared to the USA

It has been frequently acknowledged that results of predictive genetic tests may have implications for relatives as well as for the individual client. Ethicists have noted that an individual’s right to know her genetic risk may conflict with a relative’s right not to know this risk. It is hardly recognised, however, that family members may have a role in the production of test results as well.     

If you try to stop smoking,should we pay for it? The cost–utility of reimbursing smoking cessation support in the Netherlands

Background Smoking cessation can be encouraged by reimbursing the costs of smoking cessation support (SCS). The short‐term efficiency of reimbursement has been evaluated previously. However, a thorough estimate of the long‐term cost–utility is lacking. Objectives To evaluate long‐term effects of reimbursement of SCS. Methods Results from a randomized controlled trial were extrapolated to long‐term outcomes in terms of health care costs and (quality adjusted) life years (QALY) gained, using the Chronic Disease Model. Our first scenario was no reimbursement. In a second scenario, the short‐term cessation rates from the trial were extrapolated directly. Sensitivity analyses were based on the trial's confidence intervals. In the third scenario the additional use of SCS as found in the trial was combined with cessation rates from international meta‐analyses. Results Intervention costs per QALY gained compared to the reference scenario were approximately €1200 extrapolating the trial effects directly, and €4200 when combining the trial's use of SCS with the cessation rates from the literature. Taking all health care effects into account, even costs in life years gained, resulted in an estimated incremental cost–utility of €4500 and €7400, respectively. In both scenarios costs per QALY remained below €16 000 in sensitivity analyses using a life‐time horizon. Conclusions Extrapolating the higher use of SCS due to reimbursement led to more successful quitters and a gain in life years and QALYs. Accounting for overheads, administration costs and the costs of SCS, these health gains could be obtained at relatively low cost, even when including costs in life years gained. Hence, reimbursement of SCS seems to be cost‐effective from a health care perspective.     

Triazole resistance in Aspergillus fumigatus: recent insights and challenges for patient management

BackgroundTriazole resistance in Aspergillus fumigatus is widespread and threatens first-line triazole therapy in patients with Aspergillus diseases.ObjectivesTo give an overview of the microbiology, epidemiology and clinical significance of triazole resistance in aspergillosis.SourcesPubMed search for articles on resistance in Aspergillus species.ContentTriazoles are not mutagenic but select resistance when spontaneous mutations occur that are better able to proliferate in the triazole-containing environment. The major target for resistance mutations involves the Cyp51A gene, encoding an enzyme involved in cell wall synthesis. Triazole-resistance selection environments include patient treatment and organic matter containing triazole fungicide residues. Reported resistance frequencies vary widely between countries and hospitals, and resistance significantly complicates the diagnosis and treatment of Aspergillus diseases. Cultures may harbour various resistance phenotypes and multiple colonies must be analysed to detect resistance. PCR tests have become available for resistance detection in culture-negative patients, but show limited sensitivity. Individuals with triazole-resistant invasive aspergillosis have a 21% higher day-42 mortality compared with triazole-susceptible infection, and to prevent excess mortality resistant cases require first-line therapy that covers resistance. The recent ESCMID-ECMM-ERS Aspergillus guideline recommends resistance testing in A. fumigatus and local resistance surveillance. If resistance rates exceed 10% liposomal amphotericin B or triazole and echinocandin first-line therapy should be considered.ImplicationsTriazole resistance significantly complicates the management of aspergillosis and multidisciplinary research from a ‘One-health’ perspective is required to retain the triazole class for medical use.     

The radioimmunoassay of plasma-digoxin

Our experience with a commercially available kit (Lanoxitest) for the serum digoxin determination by radioimmunoassay using [³H]digoxin is reported. The different steps of the procedure are evaluated. Some modifications, especially a reduction of the time of adsorption from 10 to 1 min, lead to more accurate results.A “cito” determination can be fully completed in 1$\text{1}\text{2}$ h. Mean digoxin value in 93 non-toxic patients with normal renal function was 1.6 ng/ml (S.D. = ± 0.7 ng/ml). 22 patients, showing toxicity attributed to digoxin, had a mean level of 4.4 ng/ml (S.D. = ± 0.9 ng/ml).     

Estimation of IgM in cerebrospinal fluid by enzyme immunoassay

We have compared a nasopharyngeal catheter method for breath sampling and a valved collection device. Sample quality was assessed by simultaneous oxygen measurement and reproducibility was checked by the analysis of 50 pairs of samples from four premature neonates.Both collection methods produced samples of highly variable quality suggesting a variable mixture of alveolar and non-alveolar air as well as differences in expired oxygen levels between babies. The mean oxygen levels were similar for both sampling techniques. Linear regression analysis of paired hydrogen results showed a highly significant correlation coefficient r = 0.73. This was improved markedly to r = 0.94 by normalization of hydrogen values based on observed oxygen levels, and so supports the earlier article by Robb and Davidson [1].All breath hydrogen analyses require a measure of sample quality. Reproducible results and meaningful changes in hydrogen concentration in breath samples can only be achieved by correction according to sample quality. Correction to a common oxygen value should allow quantitative comparisons between patients. Samples were best collected from neonates by the nasopharyngeal catheter method, which least disturbed the patient, allowed multiple sample collection and gave lower oxygen and higher hydrogen values where large differences between pairs occurred.     

Experimental optimization of the detection limit of one-step solid-phase radioimmunoassay

The minimal detection limit and the conditions of maximal sensitivity of a one-step solid-phase inhibition radioimmunoassay for human immunoglobulin A have been determined by application of statistical methods of experimental optimization. The choice of the optimal combination of qualitative variables, such as the origin of the antibody and the nature of the solid phase, was made by the study of a covariable under non-optimal conditions of the quantitative variables, such as the amount of antibody. The covariable was the avidity of the antibody, which is expected to have a large influence on the sensitivity. Only the difference in avidity between two immunosorbents with cellulose or Sepharose as solid-phase material proved to be statistically significant, and further study was done with cellulose. The experimental optimization of the sensitivity as a function of five quantitative variables yielded a reduction of the detection limit by a factor 5.6 (from 23.5 to 4.2 ng IgA). The variables determining the amount of insolubilized antibody in the assay had the largest influence on the value of the detection limit. The conditions of optimal sensitivity did agree with the predictions by a physical model of radioimmunoassay. The results are discussed in relation to the assay parameters such as the amount and the avidity of the insolubilized antibody and the initial percentage of binding, and in relation with theoretical optimization of the sensitivity.