Search results for "laboratory"
showing 10 items of 923 documents
Amplification of human β-glucoronidase gene for appraising the accuracy of negative SARS-CoV-2 RT-PCR results in upper respiratory tract specimens
2020
Real-time reverse transcription polymerase-chain reaction (RT-PCR) is the mainstay of Covid-19 diagnosis. False-negative RT-PCR results may hamper clinical management of patients and hinder the adoption of epidemiological measures to control the pandemic. The current study was aimed at assessing whether amplification of β-glucoronidase (GUSB) gene would help estimate the accuracy of SARS-CoV-2 RT-PCR negative results in upper respiratory tract (URT) specimens. URT specimens that tested negative by SARS-CoV-2 RT-PCR displayed higher GUSB RT-PCR cycle thresholds (CT) (P=0.070) than those testing positive (median, 30.7; range, 27.0-40.0, and median 29.7; range 25.5-36.8, respectively), this re…
Impact of environmental temperature on skin thickness and microvascular blood flow in subjects with and without diabetes.
2006
Glucose measurement from different skin areas might be influenced by changes in skin texture due to several environmental confounders. Our study was performed to investigate the effect of changes in ambient temperature on skin thickness and microvascular skin blood flow in subjects with and without diabetes at the lower forearm.Thirteen subjects with diabetes and seven without diabetes participated in the study. The investigations were performed in a temperature- and humidity-controlled climatic chamber (EMPA, St. Gallen, Switzerland). Starting at 25 degrees C, the environmental temperature was changed in 4 degrees C steps every 40 min. Skin thickness was measured by an ultrasonic reflectio…
Microcentrifuge or Automated Hematological Analyzer to Assess Hematocrit in Exercise? Effect on Plasma Volume Loss Calculations
2016
The assessment of plasma volume loss (∆PV) induced by exercise can be estimated from changes in hematocrit (Htc) and hemoglobin (Hb), and it is essential when investigating the metabolic or biologic response to exercise of circulating biomarkers. We aimed to ascertain whether the estimation of ∆PV may differ when Hb and Htc are determined by automated hematological analyzer (AHA) versus manual methods. Twenty-five healthy male subjects performed a maximal running incremental exercise. Blood samples were taken before exercise, immediately after exercise, and after a 30-min recovery. Hb and Htc (Htc-AHA) were determined by an AHA. Htc was also determined by microcentrifugation (Htc-M). The ∆P…
(Table 1) Age determination of sediment core SO147_106KL
2005
Here we present a high-resolution marine sediment record from the El Niño region off the coast of Peru spanning the last 20,000 years. Sea surface temperature, photosynthetic pigments, and a lithic proxy for El Niño flood events on the continent are used as paleo-El Niño-Southern Oscillation proxy data. The onset of stronger El Niño activity in Peru started around 17,000 calibrated years before the present, which is later than modeling experiments show but contemporaneous with the Heinrich event 1. Maximum El Niño activity occurred during the early and late Holocene, especially during the second and third millennium B.P. The recurrence period of very strong El Niño events is 60-80 years. El…
The Development of Novel Approaches to the Identification of Chemical and Protein Respiratory Allergens
2008
In October 2006, the European Centre for theValidation of Alternative Methods (ECVAM) spon-sored and hosted a three-day workshop to consideropportunities and challenges in the development ofalternative methods for the identification and char-acterisation of chemical respiratory allergens. Theproceedings, conclusions and recommendations ofthat workshop were subsequently made available asECVAM Workshop Report 60 (1).In April 2008, a second meeting was convenedby ECVAM to consider what progress has beenmade in the light of the recommendations derivedfrom the 2006 Workshop and the publishedreport. This meeting had as a second objective —to consider whether new opportunities for theidentificatio…
Assessment of oxidative damage to proteins and DNA in urine of newborn infants by a validated UPLC-MS/MS approach
2014
The assessment of oxidative stress is highly relevant in clinical Perinatology as it is associated to adverse outcomes in newborn infants. This study summarizes results from the validation of an Ultra Performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) method for the simultaneous quantification of the urinary concentrations of a set of endogenous biomarkers, capable to provide a valid snapshot of the oxidative stress status applicable in human clinical trials, especially in the field of Perinatology. The set of analytes included are phenylalanine (Phe), para-tyrosine (p-Tyr), ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-NO2-tyrosine (3NO(2)-Tyr), 3-Cl-tyrosine (3Cl-T…
Data from: Parallel diversifications of Cremastosperma and Mosannona (Annonaceae), tropical rainforest trees tracking Neogene upheaval of South Ameri…
2017
Much of the immense present day biological diversity of Neotropical rainforests originated from the Miocene onwards, a period of geological and ecological upheaval in South America. We assess the impact of the Andean orogeny, drainage of lake Pebas, and closure of the Panama Isthmus on two clades of tropical trees (Cremastosperma, c. 31 spp.; and Mosannona, c. 14 spp.; both Annonaceae). Phylogenetic inference revealed similar patterns of geographically restricted clades and molecular dating showed diversifications in the different areas occurred in parallel, with timing consistent with Andean vicariance and Central American geodispersal. Ecological niche modelling approaches show phylogenet…
Mycotoxin contamination in laboratory rat feeds and their implications in animal research
2016
Compound feed is particularly vulnerable to multi-mycotoxin contamination. A method for the determination of 12 mycotoxins; enniatins A, A1, B, B1; aflatoxins B1, B2, G1, G2; OTA; ZEA; T-2 and HT-2 by liquid chromatography-tandem mass spectrometry has been developed and applied for the analysis of laboratory rat commercial feeds. The method trueness was checked by recovery assays at three different spiked levels (n = 9). Recoveries ranged from 73% to 112%, and the intra-day and inter-day precision were lower than 9% and 13%, respectively. Limits of quantitation were lower than 15 μg/kg. Twenty-seven laboratory rats feed samples showed multi-contamination by at least three up to six differen…
Intralaboratory validation of four in vitro assays for the prediction of the skin sensitizing potential of chemicals
2011
Abstract Allergic contact dermatitis is induced by repeated skin contact with an allergen. Assessment of the skin sensitizing potential of chemicals, agrochemicals, and especially cosmetic ingredients is currently performed with the use of animals. Animal welfare and EU legislation demand animal-free alternatives reflected in a testing and marketing ban for cosmetic ingredients beginning in 2013. The underlying mechanisms of induction and elicitation of skin sensitization are complex and a chemical needs to comply several properties being skin sensitizing. To account for the multitude of events in the induction of skin sensitization an in vitro test system will consist of a battery of vario…
Human Hepatic Cell Cultures: In Vitro and In Vivo Drug Metabolism
2003
Drug metabolism is the major determinant of drug clearance, and the factor most frequently responsible for inter-individual differences in drug pharmacokinetics. The expression of drug metabolising enzymes shows significant interspecies differences, and variability among human individuals (polymorphic or inducible enzymes) makes the accurate prediction of the metabolism of a new compound in humans difficult. Several key issues need to be addressed at the early stages of drug development to improve drug candidate selection: a) how fast the compound will be metabolised; b) what metabolites will be formed (metabolic profile); c) which enzymes are involved and to what extent; and d) whether dr…