TY  - JOUR
A1  - Raila, Jens
A1  - Enjalbert, Francis
A1  - Mothes, Ralf
A1  - Hurtienne, Andrea
A1  - Schweigert, Florian J.
T1  - Validation of a new point-of-care assay for determination of ss-carotene concentration in bovine whole blood and plasma
JF  - Veterinary clinical pathology
N2  - Background: beta-Carotene is an important precursor of vitamin A, and is associated with bovine fertility. beta-Carotene concentrations in plasma are used to optimize beta-carotene supplementation in cattle, but measurement requires specialized equipment to separate plasma and extract and measure beta-carotene, either using spectrophotometry or high performance liquid chromatography (HPLC).
 Objective: The objective of this study was to validate a new 2-step point-of-care (POC) assay for measuring beta-carotene in whole blood and plasma.
 Methods: beta-carotene concentrations in plasma from 166 cows were measured using HPLC and compared with results obtained using a POC assay, the iCheck-iEx-Carotene test kit. Whole blood samples from 23 of these cattle were also evaluated using the POC assay and compared with HPLC-plasma results from the same 23 animals. The POC assay includes an extraction vial (iEx Carotene) and hand-held photometer (iCheck Carotene).
 Results: Concentrations of beta-carotene in plasma measured using the POC assay ranged from 0.40 to 15.84 mg/L (n = 166). No differences were observed between methods for assay of plasma (mean +/- SD; n = 166): HPLC-plasma 4.23 +/- 2.35 mg/L; POC-plasma 4.49 +/- 2.36 mg/L. Similar good agreement was found when plasma analyzed using HPLC was compared with whole blood analyzed using the POC system (n = 23): HPLC-plasma 3.46 +/- 2.12 mg/L; POC-whole blood 3.67 +/- 2.29 mg/L.
 Conclusions: Concentrations of beta-carotene can be measured in blood and plasma from cattle easily and rapidly using a POC assay, and results are comparable to those obtained by the highly sophisticated HPLC method. Immediate feedback regarding beta-carotene deficiency facilitates rapid and appropriate optimization of beta-carotene supplementation in feed.
KW  - Biomarker
KW  - HPLC
KW  - method comparison
KW  - nutritional supplements
KW  - vitamin A
Y1  - 2012
U6  - https://doi.org/10.1111/j.1939-165X.2012.00400.x
SN  - 0275-6382
VL  - 41
IS  - 1
SP  - 119
EP  - 122
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - Aichner, Bernhard
A1  - Herzschuh, Ulrike
A1  - Wilkes, Heinz
A1  - Schulz, Hans-Martin
A1  - Wang, Yongbo
A1  - Plessen, Birgit
A1  - Mischke, Steffen
A1  - Diekmann, Bernhard
A1  - Zhang, Chengjun
T1  - Ecological development of Lake Donggi Cona, north-eastern Tibetan Plateau, since the late glacial on basis of organic geochemical proxies and non-pollen palynomorphs
JF  - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences
N2  - Organic geochemical proxy data from surface sediment samples and a sediment core from Lake Donggi Cona were used to infer environmental changes on the northeastern Tibetan Plateau spanning the last 18.4 kyr. Long-chain n-alkanes dominate the aliphatic hydrocarbon fraction of the sediment extract from most surface sediment samples and the sediment core. Unsaturated mid-chain n-alkanes (nC(23:1) and nC(25:1)) have high abundances in some samples, especially in core samples from the late glacial and early Holocene. TOC contents, organic biomarker and non-pollen-palynomorph concentrations and results from organic petrologic analysis on selected samples suggest three major episodes in the history of Lake Donggi Cona. Before ca. 12.6 cal ka BP samples contain low amounts of organic matter due to cold and arid conditions during the late glacial. After 12.6 cal ka BP, relatively high contents of TOC and concentrations of Botryococcus fossils, as well as enhanced concentrations of mid-chain n-alkanes and n-alkenes suggest a higher primary and macrophyte productivity than at present This is supported by high contents of palynomorphs derived from higher plants and algae and was possibly triggered by a decrease of salinity and amelioration of climate during the early Holocene. Since 6.8 cal ka BP Lake Donggi Cona has been an oligotrophic freshwater lake. Proxy data suggest that variations in insolation drive ecological changes in the lake, with increased aquatic productivity during the early Holocene summer insolation maximum. Short-term drops of TOC contents or biomarker concentrations (at 9.9 cal ka BP, after 8.0 and between 3.5 and 1.7 cal ka BP) can possibly be related to relatively cool and dry episodes reported from other sites on the north-eastern Tibetan Plateau, which are hypothesized to occur in phase with Northern Hemisphere cooling events.
KW  - Biomarker
KW  - Holocene
KW  - n-alkanes
KW  - Total organic carbon
KW  - Organic matter
KW  - Macerals
KW  - Aquatic macrophytes
Y1  - 2012
U6  - https://doi.org/10.1016/j.palaeo.2011.10.015
SN  - 0031-0182
VL  - 313
IS  - 2
SP  - 140
EP  - 149
PB  - Elsevier
CY  - Amsterdam
ER  -