Bovine Muscle Tissue Research Articles

Detection of Bovine Central Nervous System Tissues in Rendered Animal By-Products by One-Step Real-Time Reverse Transcription PCR Assay

Contamination of rendered animal byproducts with central nervous system tissues (CNST) from animals with bovine spongiform encephalopathy is considered one of the vehicles of disease transmission. Removal from the animal feed chain of CNST originated from cattle of a specified age category, species-labeling of rendered meat products, and testing of rendered products for bovine CNST are tasks associated with the epidemiological control of bovine spongiform encephalopathy. A single-step TaqMan real-time reverse transcriptase (RRT) PCR assay was developed and evaluated for specific detection of bovine glial fibrillary acidic protein (GFAP) mRNA, a biomarker of bovine CNST, in rendered animal by-products. An internal amplification control, mammalian b -actin mRNA, was coamplified in the duplex RRT-PCR assay to monitor amplification efficiency, normalize amplification signals, and avoid false-negative results. The functionality of the GFAP mRNA RRT-PCR was assessed through analysis of laboratory-generated binary mixtures of bovine central nervous system (CNS) and muscle tissues treated under various thermal settings imitating industrial conditions. The assay was able to detect as low as 0.05 % (wt/wt) bovine brain tissue in binary mixtures heat treated at 110 to 130°C for 20 to 60 min. Further evaluation of the GFAP mRNA RRT-PCR assay involved samples of industrial rendered products of various species origin and composition obtained from commercial sources and rendering plants. Low amounts of bovine GFAP mRNA were detected in several bovine-rendered products, which was in agreement with declared species composition. An accurate estimation of CNS tissue content in industrial-rendered products was complicated due to a wide range of temperature and time settings in rendering protocols. Nevertheless, the GFAP mRNA RRT-PCR assay may be considered for bovine CNS tissue detection in rendered products in combination with other available tools (for example, animal age verification) in inspection programs.

Localization and abundance of early markers of fat cell differentiation in the skeletal muscle of cattle during growth — Are DLK1-positive cells the origin of marbling flecks?

Localization and abundance of early markers of adipogenic differentiation were investigated in bovine muscle tissue to verify their association with marbling development. Bovine skeletal muscle samples were used for immunohistochemical localization and measurement of mRNA and protein abundance of delta-like homolog 1 (DLK1) and CCAAT/enhancer-binding protein beta (CEBPB). The localization of DLK1-positive cells confirmed the position of small clusters of adipocytes which can be considered as the origin of marbling flecks. The results indicated higher DLK1 expression in the less marbled muscle of Holstein (HS) steers (P<0.05) and a trend to higher CEBPB expression in Japanese Black (JB) steers (P<0.1) at slaughter. The number of DLK1-positive cells and fat content were negatively correlated. The lower expression of DLK1 together with higher CEBPB abundance during fattening in JB may have contributed to the development of more adipocytes in the skeletal muscle of JB.

Fast conductivity imaging in magnetic resonance electrical impedance tomography (MREIT) for RF ablation monitoring

Purpose: This study shows the potential of magnetic resonance electrical impedance tomography (MREIT) as a non-invasive RF ablation monitoring technique.Materials and methods: We prepared bovine muscle tissue with a pair of needle electrodes for RF ablation, a temperature sensor, and two pairs of surface electrodes for conductivity image reconstructions. We used the injected current non-linear encoding with multi-echo gradient recalled echo (ICNE-MGRE) pulse sequence in a series of MREIT scans for conductivity imaging. We acquired magnetic flux density data induced by externally injected currents, while suppressing other phase artefacts. We used an 8-channel RF head coil and 8 echoes to improve the signal-to-noise ratio (SNR) in measured magnetic flux density data. Using the measured data, we reconstructed a time series of 180 conductivity images at every 10.24 s during and after RF ablation.Results: Tissue conductivity values in the lesion increased with temperature during RF ablation. After reaching 60 °C, a steep increase in tissue conductivity values occurred with relatively little temperature increase. After RF ablation, tissue conductivity values in the lesion decreased with temperature, but to values different from those before ablation due to permanent structural changes of tissue by RF ablation.Conclusion: We could monitor temperature and also structural changes in tissue during RF ablation by producing spatio-temporal maps of tissue conductivity values using a fast MREIT conductivity imaging method. We expect that the new monitoring method could be used to estimate lesions during RF ablation and improve the efficacy of the treatment.

Genome-wide DNA methylation profiles and their relationships with mRNA and the microRNA transcriptome in bovine muscle tissue (Bos taurine).

DNA methylation is a key epigenetic modification in mammals and plays important roles in muscle development. We sampled longissimus dorsi muscle (LDM) from a well-known elite native breed of Chinese Qinchuan cattle living within the same environment but displaying distinct skeletal muscle at the fetal and adult stages. We generated and provided a genome-wide landscape of DNA methylomes and their relationship with mRNA and miRNA for fetal and adult muscle studies. Integration analysis revealed a total of 77 and 1,054 negatively correlated genes with methylation in the promoter and gene body regions, respectively, in both the fetal and adult bovine libraries. Furthermore, we identified expression patterns of high-read genes that exhibit a negative correlation between methylation and expression from nine different tissues at multiple developmental stages of bovine muscle-related tissue or organs. In addition, we validated the MeDIP-Seq results by bisulfite sequencing PCR (BSP) in some of the differentially methylated promoters. Together, these results provide valuable data for future biomedical research and genomic and epigenomic studies of bovine skeletal muscle that may help uncover the molecular basis underlying economically valuable traits in cattle. This comprehensive map also provides a solid basis for exploring the epigenetic mechanisms of muscle growth and development.

Rapid tissue dissolution efficiency of electrically-activated sodium hypochlorite on bovine muscle.

Objective:Sodium hypochlorite (NaOCl) is a common antimicrobial and tissue-dissolving irrigant. The aim of this in vitro study is to evaluate and compare dissolution capacities of sodium hypochlorite solutions after electrically activation (E-NaOCl) on bovine muscle specimens at various time periods and concentrations.Materials and Methods:Three sodium hypochlorite solutions of 1.25%, 2.5%, and 5% were tested at 3-min. and 5-min. with and without activation by electrically. Distilled water and NaOCl solutions without electrically activation were used as controls. Pieces of bovine muscle tissue (34 ± 2 mg) were placed in 10 mL of each solution at room temperature. In the group of E-NaOCl, electrically activation was performed through the potentiostat. The tissue specimens were weighed before and after treatment, and the percentage of weight loss was calculated.Results:Weight loss of the tissue increased with the concentration of E-NaOCl and NaOCl. Higher concentration and electrically activation considerably enhanced the efficacy of sodium hypochlorite. The effect of electrically activation on tissue dissolution was much greater than that of same concentrations in the groups of NaOCl (P < 0.001). Tissue weight loss was significantly higher in 2.5% and 5% E-NaOCl at 3 min. than in 2.5% and 5% NaOCl at 5 min. (P < 0.05). There were not any significant differences between the 2.5% E-NaOCl and 5% NaOCl at 5 min. (P > 0.05).Conclusion:Electrically activation can improve the tissue-dissolving effectiveness of sodium hypochlorite.

Bioanalytical methods for the metalloproteomics study of bovine longissimus thoracis muscle tissue with different grades of meat tenderness in the Nellore breed (Bos indicus)

The work describes a metalloproteomics study of bovine muscle tissue with different grades of meat tenderness from animals of the Nellore breed (Bos indicus) based on protein separation by two-dimensional gel electrophoresis, the identification of calcium ions in protein spots by X-ray fluorescence (SR-XRF) and the characterisation of proteins by electrospray ionisation mass spectrometry. Forty (40) specimens were selected and divided into two experimental groups: animals with tough meat (TO) and animals with tender meat (TE). A third group (P) of Piedmontese breed animals (Bos taurus) was included to serve as a comparative model for the level of meat tenderness. The procedures were efficient and preserved the metal–protein structure, enabling calcium detection in protein spots by SR-XRF at a given molecular weight range of 14–97kDa. Two proteins (pyruvate kinase and albumin) were inferred to be related to the phenotypical differences in animals from the different groups.

A novel approach to the quantitative detection of anabolic steroids in bovine muscle tissue by means of a hybrid quadrupole time-of-flight-mass spectrometry instrument

In recent years, the analysis of veterinary drugs and growth-promoting agents has shifted from target-oriented procedures, mainly based on liquid chromatography coupled to triple-quadrupole mass spectrometry (LC-QqQ-MS), towards accurate mass full scan MS (such as Time-of-Flight (ToF) and Fourier Transform (FT)-MS). In this study, the performance of a hybrid analysis instrument (i.e. UHPLC-QuadrupoleTime-of-Flight-MS (QqToF-MS)), able to exploit both full scan HR and MS/MS capabilities within a single analytical platform, was evaluated for confirmatory analysis of anabolic steroids (gestagens, estrogens including stilbenes and androgens) in meat. The validation data was compared to previously obtained results (CD 2002/657/EC) for QqQ-MS and single stage Orbitrap-MS. Additionally, a fractional factorial design was used to shorten and optimize the sample extraction. Validation according to CD 2002/657/EC demonstrated that steroid analysis using QqToF has a higher competing value towards QqQ-MS in terms of selectivity/specificity, compared to single stage Orbitrap-MS. While providing excellent linearity, based on lack-of-fit calculations (F-test, α=0.05 for all steroids except 17β-ethinylestradiol: α=0.01), the sensitivity of QqToF-MS proved for 61.8% and 85.3% of the compounds more sensitive compared to QqQ-MS and Orbitrap-MS, respectively. Indeed, the CCα values, obtained upon ToF-MS/MS detection, ranged from 0.02 to 1.74μgkg−1 for the 34 anabolic steroids, while for QqQ-MS and Orbitrap-MS values ranged from 0.04 to 0.88μgkg−1 and from 0.07 to 2.50μgkg−1, respectively. Using QqToF-MS and QqQ-MS, adequate precision was obtained as relative standard deviations for repeatability and within-laboratory reproducibility, were below 20%. In case of Orbitrap-MS, some compounds (i.e. some estrogens) displayed poor precision, which was possibly caused by some lack of sensitivity at lower concentrations and the absence of MRM-like experiments. Overall, it can be concluded that QqToF-MS offers good quantitative and confirmatory performance using the ToF-MS/MS mode whereas the full scan HR-ToF-MS allows screening for potential new designer drugs.

Etidronate causes minimal changes in the ability of sodium hypochlorite to dissolve organic matter.

To evaluate the effect of individual and combined use of sodium hypochlorite (NaOCl), etidronate (HEDP) and ethylenediaminetetraacetic acid (EDTA) in tissue dissolution. Sixty fragments of bovine muscle tissue were prepared and their weights determined on a precision scale. The samples were then distributed in the following groups (n=10): G1 - saline solution (control); G2 - 17% EDTA; G3 - 18% HEDP; G4 - 2.5% NaOCl; G5 - mixture of 5% NaOCl+17% EDTA; and G6 - mixture of 5% NaOCl+18% HEDP. The specimens in each group were immersed in the solutions for 5, 10 and 15min and reweighted at each time period. Analysis of variance (anova) and Tukey's multiple-comparison tests (α<0.05) were applied to identify the intragroup and intergroup differences. G1, G2, G3 and G5 did not dissolve the organic matter. G4 and G6 significantly reduced the weights of specimens at all periods. Amongst the groups, the difference in ability to dissolve organic matter was greater and significant in the following order G4=G6>G5=G3=G2=G1 after 5min of immersion and G4>G6>G5=G3=G2=G1 after 10 and 15min of immersion. The only solution capable of dissolving organic matter was NaOCl. In the mixtures analysed, this ability was arrested by EDTA; however, it was minimally affected by the HEDP, proving that this combination, if used during the biomechanical preparation, is able to dissolve of organic matter.

In vitro terahertz monitoring of muscle tissue dehydration under the action of hyperosmotic agents

Dehydration of muscle tissue in vitro under the action of biologically compatible hyperosmotic agents is studied using a laser terahertz spectrometer in the frequency range from 0.25 to . Broadband terahertz absorption and reflection spectra of the bovine skeletal muscle tissue were obtained under the action of glycerol, polyethylene glycol with the molecular weight 600 (PEG-600), and propylene glycol. The presented results are proposed for application in developing the methods of image contrast enhancement and increasing the depth of biological tissue probing with terahertz radiation.

Historical Overview of the Effect of β-Adrenergic Agonists on Beef Cattle Production.

Postnatal muscle hypertrophy of beef cattle is the result of enhanced myofibrillar protein synthesis and reduced protein turnover. Skeletal muscle hypertrophy has been studied in cattle fed β-adrenergic agonists (β-AA), which are receptor-mediated enhancers of protein synthesis and inhibitors of protein degradation. Feeding β-AA to beef cattle increases longissimus muscle cross-sectional area 6% to 40% compared to non-treated cattle. The β-AA have been reported to improve live animal performance, including average daily gain, feed efficiency, hot carcass weight, and dressing percentage. Treatment with β-AA increased mRNA concentration of the β2 or β1-adrenergic receptor and myosin heavy chain IIX in bovine skeletal muscle tissue. This review will examine the effects of skeletal muscle and adipose development with β-AA, and will interpret how the use of β-AA affects performance, body composition, and growth in beef cattle.

A Quantum Dot-Based Immunoassay for Screening of Tetracyclines in Bovine Muscle

A reliable and robust direct screening methodology based on a quantum dot (QD) fluorescent immunoassay has been developed to detect trace levels of different antibiotic species from the family of the tetracyclines (e.g., oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in contaminated bovine muscle tissues. First, the synthesis and characterization of a new immunoprobe (oxytetracycline-bovine serum albumin-QD) has been carried out for its further application in the development of a competitive fluorescent QD-immunoassay. The developed fluoroimmunoassay provides sensitive and binary "yes/no" responses being appropriate for the screening of this family of antibiotics above or below a preset concentration threshold. The detection limit achieved with this strategy, 1 μg/L in aqueous media and 10 μg/kg in bovine muscle samples, is 10-fold lower than the maximum level concentration allowed by International Legislation in muscle tissue, enabling suitable and efficient screening of the antibiotics.

Tissue Dissolution by a Novel Multisonic Ultracleaning System and Sodium Hypochlorite

IntroductionThis study aimed to evaluate the effectiveness of a novel Multisonic Ultracleaning System (Sonendo Inc, Laguna Hills, CA) in tissue dissolution in comparison with conventional irrigation devices. MethodsPieces of bovine muscle tissue (68 ± 2 mg) were placed in 0.7-mL test tubes (height: 23.60 mm, inner diameter: 6.00 mm, outer diameter: 7.75 mm) and exposed to 5 minutes of irrigation by different devices. Endodontic devices included the Multisonic Ultracleaning System, the Piezon Master 700 (EMS, Dallas, TX) ultrasonic system with agitation, the EndoVac negative-pressure irrigation system (SybronEndo, Orange, CA), and a conventional positive-pressure 27-G irrigation needle at a flow rate of 10 mL/min. The systems were tested with 0.5%, 3%, and 6% sodium hypochlorite (NaOCl) at room temperature (21°C) as well as 40°C. Irrigation with sterile water was used as a control. The mass of tissue specimens was measured and recorded before and after the use of each device, and if the specimen was completely dissolved visually within 5 minutes, the dissolution time was recorded. The rate of tissue dissolution (%/s) was then calculated. ResultsThe Multisonic Ultracleaning System had the fastest rate of tissue dissolution (P < .05), at 1.0% ± 0.1% per second using 0.5% NaOCl, 2.3% ± 0.9% per second using 3% NaOCl, and 2.9% ± 0.7% per second using 6% NaOCl. This tissue dissolution rate was more than 8 times greater than the second fastest device tested (P < .01), the Piezon Master 700 ultrasonic system, which resulted in a tissue dissolution rate of 0.328% ± 0.002% per second using 6% NaOCl at 40°C. For all irrigation devices tested, the rate of tissue dissolution increased with a higher concentration and temperature of the NaOCl solution. ConclusionsThe novel Multisonic Ultracleaning System achieved a significantly faster tissue dissolution rate when compared with the other systems examined in vitro.

Determination of Corticosteroids, Anabolic Steroids, and Basic Nonsteroidal Anti-Inflammatory Drugs in Milk and Animal Tissues

A quantitative LC/MS/MS method was developed for the determination of 14 steroidal compounds and three basic nonsteroidal anti-inflammatory drugs (detected as metabolites) in bovine milk and animal muscle tissue. The proposed method is sufficiently sensitive and highly selective for residue applications. The described approach offers the possibility to detect, quantify, and confirm anti-inflammatory drugs belonging to two widely diverging chemical categories. The employed single-stage SPE step (mixed mode cation exchange) retains both steroids and basic metabolites of nonsteroidal anti-inflammatory drugs. The method is capable of handling widely diverging relevant concentration ranges (0.1 microg/kg for dexamethasone and 100 microg/kg for metamizol metabolites) for the individual compounds with a single extraction, cleanup, and LC/MS/MS procedure. It provides good analyte precision and accuracy data.

Determination of stilbenes and resorcylic acid lactones in bovine, porcine and poultry muscle tissue by liquid chromatography–negative ion electrospray mass spectrometry and QuEChERS for sample preparation

Liquid chromatography tandem mass spectrometry method was developed and validated to confirm of resorcylic acid lactones: zeranol, taleranol, zearalanone, zearalenone, α and β-zearalenol and stilbenes in muscle tissue. The compounds were analyzed by LC-MS/MS QTrap 5500 apparatus in negative ionization mode. Chromatographic separation on Poroshell 120-EC C18 (150mm×2.1mm, 2.7μm) column was achieved at 45°C using isocratic elution of mobile phase - methanol/water (65:35, v/v). For the treatment of tissue samples prior to analysis, QuEChERS method was applied based on the extraction of analytes from muscle samples with ethyl acetate, separation of the aqueous and organic phases with application of magnesium sulphate and sodium acetate, the purification of the extract obtained by dispersive SPE with the use of sorbent C18, PSA and magnesium sulphate. The method was validated in accordance with the Commission Decision 2002/657/EC. Good recoveries were obtained (from 83% to 115%) as well as acceptable within-lab reproducibility (<22%). The values of the decision limit CCα and the detection capability CCβ for individual compounds are found to be below the recommended concentration set at 1μgkg(-1) and not exceed 0.23μgkg(-1) and 0.39μgkg(-1), respectively. The elaborated method meets the criteria for confirmatory methods and is used in the official control of hormones.

Rapid analysis of aminoglycoside antibiotics in bovine tissues using disposable pipette extraction and ultrahigh performance liquid chromatography–tandem mass spectrometry

A high-throughput qualitative screening and identification method for 9 aminoglycosides of regulatory interest has been developed, validated, and implemented for bovine kidney, liver, and muscle tissues. The method involves extraction at previously validated conditions, cleanup using disposable pipette extraction, and analysis by a 3min ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method. The drug analytes include neomycin, streptomycin, dihydrosptreptomycin, and spectinomycin, which have residue tolerances in bovine in the US, and kanamicin, gentamicin, apramycin, amikacin, and hygromycin, which do not have US tolerances established in bovine tissues. Tobramycin was used as an internal standard. An additional drug, paromomycin also was validated in the method, but it was dropped during implementation due to conversion of neomycin into paromomycin. Proposed fragmentation patterns for the monitored ions of each analyte were elucidated with the aid of high resolution MS using a quadrupole-time-of-flight instrument. Recoveries from spiking experiments at regulatory levels of concern showed that all analytes averaged 70–120% recoveries in all tissues, except hygromycin averaged 61% recovery. Lowest calibrated levels were as low as 0.005μg/g in matrix extracts, which approximately corresponded to the limit of detection for screening purposes. Drug identifications at levels <0.05μg/g were made in spiked and/or real samples for all analytes and tissues tested. Analyses of 60 samples from 20 slaughtered cattle previously screened positive for aminoglycosides showed that this method worked well in practice. The UHPLC–MS/MS method has several advantages compared to the previous microbial inhibition screening assay, especially for distinguishing individual drugs from a mixture and improving identification of gentamicin in tissue samples.

Beef authentication using dietary markers: Chemometric selection and modelling of significant beef biomarkers using concatenated data from multiple analytical methods

This work aimed to identify a combination of isotopic and molecular biomarkers in bovine muscle and adipose tissue for authentication of the diet of beef cattle. Muscle and adipose tissue samples were collected from animals one of four dietary treatments fed over a 1year period : pasture (P), barley-based concentrate (C), silage followed by pasture (SiP) or silage followed by pasture with concentrate (SiPC). In total, 83 variables were studied including volatile compounds, colour and reflectance measurements, stable isotope ratios, fatty acids, β-carotene, lutein and α-tocopherol. Chemometric models were created for each dietary treatment using the entire and an attenuated variable set. Meat from each dietary treatment was identified with a high level of accuracy (correct classification between 90.8% and 100%) using a discriminant approach. After elimination of insignificant variables, accuracy was maintained or marginally improved. SIMCA class-modelling performed moderately well, especially with the reduced variable set (76.1–100% correct classification).

Determination of 20 coccidiostats in milk, duck muscle and non-avian muscle tissue using UHPLC-MS/MS

In this paper, methods were developed to measure coccidiostats in bovine milk, duck muscle and non-avian species. The methods were validated to the maximum levels and MRLs laid down in European Union legislation. A simple sample preparation procedure was developed for the isolation of coccidiostat residues from bovine, ovine, equine, porcine and duck muscle tissue, based on solvent extraction with acetonitrile and concentration. An alternative method had to be developed for milk samples based on the QuEChERS sample preparation approach because of the high water content in this matrix. Milk samples were adjusted to basic pH with sodium hydroxide and extracted by using a slurry of acetonitrile, MgSO4 and NaCl. Purified sample extracts were subsequently analysed by using UHPLC-MS/MS in a 13.2-min chromatographic run. It was found that the use of rapid polarity switching enabled both negatively and positively charged ions to be analysed from a single injection. By using this approach, solvent usage was reduced significantly and sample throughput improved. The method was validated for the analysis of 20 coccidiostats (arprinocid, clopidol, decoquinate, diclazuril, diaveridine, ethopabate, halofuginone, laidlomycin, lasalocid, maduramicin, monensin, narasin, nequinate, nicarbazin, robenidine, salinomycin, semduramicin, toltrazuril, toltrazuril sulphoxide and toltrazuril sulphone) in muscle and milk. The method is quantitative for toltrazurils, but it cannot be used for confirmation because only the precursor ion is monitored. Accuracy values for muscle ranged from 80% to 125%, while CCα ranged from 2.2 µg kg−1 for clopidol to 122 µg kg−1 for toltrazuril sulphoxide. Bovine milk accuracy ranged from 84% to 120% for all analytes except maduramicin, semduramicin and salinomycin, for which the values were higher. CCα values achieved ranged from 1.1 µg kg−1 for arprinocid, nequinate and lasalocid to 27 µg kg−1 for toltrazuril.

The Effect of an Olfactory and Visual Cue on Realism and Engagement in a Health Care Simulation Experience

Fidelity has been identified as an important element in a subject's perception of realism and engagement in learning during a simulation experience. The purpose of this study was to determine whether an isolated visual and olfactory sensory change to the simulation environment affects the subjects' perceptions of realism during simulation cases. Using an electrosurgical unit applied to bovine muscle tissue, we created a model to simulate the characteristic operating room smoke and burning odor that occur during many procedures. Anesthesiologist subjects were randomly assigned to an intervention group that participated in a simulation involving the characteristic smoke and odor or a control group whose simulation involved no smoke or odor. Subjects completed a 7-question survey on the fidelity of the simulation, their perception of realism, and their learning engagement. We enrolled 103 subjects over 22 simulation courses in our study (intervention, n = 52; control, n = 51). The subjects' reactions to the physical (P = 0.73), conceptual (P = 0.34), and emotional (P = 0.12) fidelity and their perception of realism (P = 0.71) did not differ between the intervention and control groups. In a high-fidelity simulation environment, a visual and olfactory increment to physical fidelity did not affect subjects' overall ratings of fidelity, perceptions of realism, and engagement in the learning experience.

In-house validation and factorial effect analysis of a liquid chromatography–tandem mass spectrometry method for the determination of corticosteroids in bovine and porcine muscle tissue

A sensitive and robust liquid chromatography-tandem mass spectrometry method allowing the rapid screening and confirmation of ten synthetic corticosteroids in bovine and porcine muscle tissue was developed and validated. The validation was conducted according to Commission Decision 2002/657/EC, Sect. 3.1.3 ("Validation according to alternative models"), by applying a matrix-comprehensive in-house validation concept. The decision limit, detection capability, recovery, repeatability, within-laboratory-reproducibility and measurement uncertainty were calculated. Furthermore, a factorial effect analysis was conducted to identify factors that have a significant influence on the method. To this end, factors considered to be relevant for the method in routine analysis (e.g. operator, duration of storage of the extracts before measurement, different lots of the cartridges and different species) were systematically varied on two levels during the validation study. Subsequently, the extent to which these factors influence the measurement results of the individual analytes was examined.

Dielectric properties of muscle and liver from 500 MHz–40 GHz

Dielectric properties are the most important parameters determining energy deposition when biological tissues are exposed to radio frequency and microwave fields. Energy absorption is determined by the specific absorption rate (SAR). SAR distributions can be computed accurately only if the complex relative permittivity of the target tissue is known to a sufficiently high accuracy, and currently there is a lack of data on the dielectric properties of biological tissues at high frequencies. In this study, tissue dielectric properties are measured using an open-ended coaxial probe technique from 500 MHz up to 40 GHz. We present dielectric data for ex vivo bovine and porcine muscle and liver tissues at 37 °C. One-pole Cole–Cole model is used to fit the measured data as a function of frequency and the dispersion parameters are presented. This data is supported by an accurate study on reference liquids such as methanol and ethanediol.