A Dilution Method to Mitigate Biotin Interference in Cardiac Troponin T Testing.

BACKGROUND: Oral biotin supplementation is known to interfere with biotin-streptavidin-based immunoassays, including Roche's fifth-generation cardiac troponin T (cTnT) assay, which plays a critical role in the diagnosis of myocardial infarction (MI). The utility of dilution, a quick and easy method to detect and remove interferences, has not been published for biotin interference. METHODS: Concentrations of cTnT were measured in pooled serum from clinical samples. Serum samples were supplemented with biotin to known concentrations, then cTnT concentrations were remeasured to assess for biotin interference. Samples were then diluted to assess for effective removal of biotin interference. RESULTS: At cTnT values near the critical reporting range for our institution (100 ng/L) we observed significant interference in measured values with added biotin concentrations above 50 ng/mL. In specimens without added biotin, autodilution at a 1:10 ratio yielded a mean 157% capture of measured cTnT, precluding the use of autodilution for detecting and mitigating biotin interference. A 1:10 dilution with serum containing 20-30 ng/L cTnT yielded a mean capture of 107%, which was suitable for detecting underlying biotin interference in supplemented samples. CONCLUSIONS: Biotin interference, at supraphysiologic concentrations, may create an artifactual reduction in measured cTnT to levels that could lead to delayed detection of an MI. Dilution with serum of known cTnT concentration of 20-30 ng/L is a fast and effective method to mitigate the analytical consequences of biotin interference.

Replications of fundamental research models in ultra high dilutions 1994 and 2015--update on a bibliometric study.

INTRODUCTION: This paper focuses exclusively on experimental models with ultra high dilutions (i.e. beyond 10(-23)) that have been submitted to replication scrutiny. It updates previous surveys, considers suggestions made by the research community and compares the state of replication in 1994 with that in 2015. METHODS: Following literature research, biochemical, immunological, botanical, cell biological and zoological studies on ultra high dilutions (potencies) were included. Reports were grouped into initial studies, laboratory-internal, multicentre and external replications. Repetition could yield either comparable, or zero, or opposite results. The null-hypothesis was that test and control groups would not be distinguishable (zero effect). RESULTS: A total of 126 studies were found. From these, 28 were initial studies. When all 98 replicative studies were considered, 70.4% (i.e. 69) reported a result comparable to that of the initial study, 20.4% (20) zero effect and 9.2% (9) an opposite result. Both for the studies until 1994 and the studies 1995-2015 the null-hypothesis (dominance of zero results) should be rejected. Furthermore, the odds of finding a comparable result are generally higher than of finding an opposite result. Although this is true for all three types of replication studies, the fraction of comparable studies diminishes from laboratory-internal (total 82.9%) to multicentre (total 75%) to external (total 48.3%), while the fraction of opposite results was 4.9%, 10.7% and 13.8%. Furthermore, it became obvious that the probability of an external replication producing comparable results is bigger for models that had already been further scrutinized by the initial researchers. CONCLUSIONS: We found 28 experimental models which underwent replication. In total, 24 models were replicated with comparable results, 12 models with zero effect, and 6 models with opposite results. Five models were externally reproduced with comparable results. We encourage further replications of studies in order to learn more about the model systems used.

Rapid speciation and quantification of selenium compounds by HPLC-ICP MS using multiple standards labelled with different isotopes.

Speciation analysis using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP MS) is now commonly used to investigate metabolic and toxicological aspects of some metals and metalloids. We have developed a rapid method for simultaneous identification and quantification of metabolites of selenium (Se) compounds using multiple standards labelled with different isotopes. A mixture of the labelled standards was spiked in a selenised garlic extract and the sample was subjected to speciation analysis by HPLC-ICP MS. The selenised garlic contains γ-glutamyl-methylselenocysteine, methylselenocysteine, and selenomethionine and the concentrations of those Se compounds were 723.8, 414.8, and 310.7 ng Se ml(-1), respectively. The isotopically labelled standards were also applied to the speciation of Se in rat urine. Selenate, methylselenonic acid, selenosugar, and trimethyselenium ions were found to be excreted by the present speciation procedure. Multiple standards labelled with different stable isotopes enable high-throughput identification and quantitative measurements of Se metabolites.

A new approach to the memory of water.

We investigated whether water has a 'memory' for succussion compared to unsuccussed controls. The method is based on a bioassay using dinoflagellates. The duration of memory measured by this method is at least 10 min, and may be longer. The effect may be based upon solitons. A hypothesis about the mode of action of homeopathy may be experimentally investigated by this method.

Evaluación antimicrobiana de 4 productos derivados del ácido piroleñoso para su posible utilización como desinfectantes / Antimicrobial evaluation of 4 products derived from the pirolegneous acid for their possible use as disinfectants

Se evaluó la efectividad antimicrobiana de 4 productos derivados del ácido piroleñoso (LQ 501-10, LQ 501-20, LQ 502-10 y LQ 502-20), según la metodologia CAME. Los 4 productos tienen buena efectividad antimicrobiana a la concentración del 6 por ciento. El estudio práctico en áreas quirúrgicas mostró una gran reducción de unidades formadoras de colonias después de la desinfección. En el estudio toxicológico se aprecia que los 4 productos son aptos para el uso propuesto. Se recomienda su utilización como desinfectantes de superficie (paredes, pisos, mesetas, etc), además pueden emplearse como limpiador. Los 4 productos formulados se pusieron en práctica y se incluyeron en el Registro de Productos Sanitarios(AU)

Evaluación antimicrobiana de 4 productos derivados del ácido piroleñoso para su posible utilización como desinfectantes / Antimicrobial evaluation of 4 products derived from the pirolegneous acid for their possible use as disinfectants

Se evaluó la efectividad antimicrobiana de 4 productos derivados del ácido piroleñoso (LQ 501-10, LQ 501-20, LQ 502-10 y LQ 502-20), según la metodologia CAME. Los 4 productos tienen buena efectividad antimicrobiana a la concentración del 6 por ciento. El estudio práctico en áreas quirúrgicas mostró una gran reducción de unidades formadoras de colonias después de la desinfección. En el estudio toxicológico se aprecia que los 4 productos son aptos para el uso propuesto. Se recomienda su utilización como desinfectantes de superficie (paredes, pisos, mesetas, etc), además pueden emplearse como limpiador. Los 4 productos formulados se pusieron en práctica y se incluyeron en el Registro de Productos Sanitarios