No abstract

Background:An individualised risk-stratified screening for prostate cancer (PCa) would select the patients who will benefit from further investigations as well as therapy. Current detection methods suffer from low sensitivity and specificity, especially for separating PCa from benign prostatic conditions. We have investigated the use of metabolomics analyses of blood samples for separating PCa patients and controls with benign prostatic hyperplasia (BPH).Methods:Blood plasma and serum samples from 29 PCa patient and 21 controls with BPH were analysed by metabolomics analysis using magnetic resonance spectroscopy, mass spectrometry and gas chromatography. Differences in blood metabolic patterns were examined by multivariate and univariate statistics.Results:By combining results from different methodological platforms, PCa patients and controls were separated with a sensitivity and specificity of 81.5% and 75.2%, respectively.Conclusions:The combined analysis of serum and plasma samples by different metabolomics measurement techniques gave successful discrimination of PCa and controls, and provided metabolic markers and insight into the processes characteristic of PCa. Our results suggest changes in fatty acid (acylcarnitines), choline (glycerophospholipids) and amino acid metabolism (arginine) as markers for PCa compared with BPH.

No abstract

The world's fisheries and aquaculture industries produce vast amounts of protein-containing by-products that can be enzymatically hydrolysed to smaller peptides and possibly be used as additives to functional foods and nutraceuticals targeted for patients with obesity-related metabolic disorders. To investigate the effects of fish protein hydrolysates on markers of metabolic disorders, obese Zucker fa/fa rats consumed diets with 75 % of protein from casein/whey (CAS) and 25 % from herring (HER) or salmon (SAL) protein hydrolysate from rest raw material, or 100 % protein from CAS for 4 weeks. The fatty acid compositions were similar in the experimental diets, and none of them contained any long-chain n-3 PUFA. Ratios of lysine:arginine and methionine:glycine were lower in HER and SAL diets when compared with CAS, and taurine was detected only in fish protein hydrolysate diets. Motifs with reported hypocholesterolemic or antidiabetic activities were identified in both fish protein hydrolysates. Rats fed HER diet had lower serum HDL-cholesterol and LDL-cholesterol, and higher serum TAG, MUFA and n-3:n-6 PUFA ratio compared with CAS-fed rats. SAL rats gained more weight and had better postprandial glucose regulation compared with CAS rats. Serum lipids and fatty acids were only marginally affected by SAL, but adipose tissue contained less total SFA and more total n-3 PUFA when compared with CAS. To conclude, diets containing hydrolysed rest raw material from herring or salmon proteins may affect growth, lipid metabolism, postprandial glucose regulation and fatty acid composition in serum and adipose tissue in obese Zucker rats.

No abstract

Determination of trans double bonds in polyunsaturated fatty acid methyl esters from their electron impact mass spectraThe geometrical isomers of unsaturated fatty acid methyl esters were analysed by gas chromatography -electron impact mass spectrometry. Distinct differences in the electron impact mass spectra of methylene-interrupted tri-and tetra-unsaturated fatty acid methyl esters were observed. The differences were particularly related to the geometry of the central double bond in trienes or the two central double bonds in tetraenes. Trans geometry in these positions led to a significant decrease of m/z 79 [C 6 H 7 ] + , which is the base peak in the all-cis isomers. Disappearance or significant reductions of ions that are used for the determination of double bond positions in the corresponding cis isomers were also observed in the same spectra. The observed differences may be of help in the identification of double bond geometry in fatty acid isomers.

A low intake of cod protein (25% of protein intake) was sufficient to beneficially affect lipid metabolism and postprandial glucose regulation in obese fa/fa rats.

Geometrical isomerisation of eicosapentaenoic and docosahexaenoic acid at high temperaturesConcentrates of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were heated at 140-240 7C for 2-8 h under nitrogen. The trans isomers were analysed by gas chromatography-mass spectrometry on a BPX-70 cyanopropyl column. All geometrical isomers of EPA and DHA with one trans double bond were observed. The rate constants (k) for the isomerisation of the all-cis isomers were calculated and found to be higher than previously reported for linoleic acid and a-linolenic acid. Arrhenius plots showed a linear relationship between ln k and the reciprocal absolute temperature above 180 7C. The distribution patterns of isomers with one trans double bond are approximately constant up to a degree of isomerisation of 25%. The degree of isomerisation can therefore be estimated from selected trans peaks.