Effects of restricted methionine and energy intake on egg weight and shell quality

Selostus: Metioniinin ja energian saannin rajoittamisen vaikutukset kananmunan painoon ja laatuun

Islet antigen-specific T cells and regulatory T cells in type 1 diabetes

T cells are the key players in the development of type 1 diabetes (T1D), mediating autoimmune reactions leading to the destruction of insulin producing beta cells in the islets. We aimed to analyze the role of different T-cell subtypes in the autoimmunity and pathogenesis of T1D. The frequency of islet antigen-specific (GAD65-, proinsulin-, and insulin-specific) CD4+ T cells was investigated in vitro in T1D patients, at-risk individuals (diabetes-associated autoantibody positive), and in controls, using MHC class II tetramers. An overall higher frequency of CD4+ T-cells recognizing the GAD65 555−567 peptide was detected in at-risk individuals. In addition, increased CD4+ T-cell responses to the same GAD65 epitope displaying a memory phenotype were observed in at-risk and diabetic children, which demonstrate a previous encounter with the antigen in vivo. Avidity and phenotypic differences were also observed among CD4+ T-cell clones induced by distinct doses of GAD65 autoantigen. T-cell clones generated at the lowest peptide dose displayed the highest avidity and expressed more frequently the TCR Vβ5.1 chain than low-avidity T cells. These findings raise attention to the antigen dose when investigating the diversity of antigen-specific T cells. Furthermore, an increased regulatory response during the preclinical phase of T1D was also found in genetically at-risk children. Higher frequencies of regulatory T (Treg) cells (CD4+CD25_high HLA-DR-/CD69-) and natural killer T (NKT) cells (CD161+Vbeta11+) were observed in children with multiple autoantibodies compared to autoantibody-negative controls. Taken together, these data showed increased frequency of islet-specific CD4+ T-cells, especially to the GAD65 555-567 epitope, and Treg and NKT cell upregulation in children at-risk for T1D, suggesting their importance in T1D pathogenesis

Fractionation of Hen Egg and Oat Lipids with supercritical Fluids Chemical and functional Properties of Fractions

Hen eggs and oats (Avena Sativa) are important materials for the food industry. Today, instead of merely satisfying the feeling of hunger, consumers are asking for healthier, biologically active and environmentally friendly products. The growing awareness of consumers’ increasing demands presents a great challenge to the food industry to develop more sustainable products and utilise modern and effective techniques. The modification of yolk fatty acid composition by means of feed supplements is well understood. Egg yolk phospholipids are polar lipids and are used in several applications including food, cosmetics, pharmaceuticals, and special nutrients. Egg yolk phospholipids are excellent emulsifiers, typically sold as mixtures of phospholipids, triacylglycerols, and cholesterol. However, highly purified and characterised phospholipids are needed in several sophisticated applications. Industrial fractionation of phospholipids is usually based on organic solvents. With these fractionation techniques, some harmful residues of organic solvents may cause problems in further processing. The objective of the present study was to investigate the methods to improve the functional properties of eggs, to develop techniques to isolate the fractions responsible for the specific functional properties of egg yolk lipids, and to apply the developed techniques to plant-based materials, too. Fractionation techniques based on supercritical fluids were utilised for the separation of the lipid fractions of eggs and oats. The chemical and functional characterisation of the fractions were performed, and the produced oat polar lipid fractions were tested as protective barrier in encapsulation processes. Modifying the fatty acid compositions of egg yolks with different types of oil supplements in feed had no affect on their functional or sensory properties. Based on the results of functional and sensory analysis, it is evident that eggs with modified fatty acid compositions are usable in several industrial applications. These applications include liquid egg yolk products used in mayonnaise and salad dressings. Egg yolk powders were utilised in different kinds of fractionation processes. The precipitation method developed in this study resembles the supercritical anti-solvent method, which is typically used in the pharmaceutical industry. With pilot scale supercritical fluid processes, non-polar lipids and polar lipids were successfully separated from commercially produced egg yolk powder and oat flakes. The egg and oat-based polar lipid fractions showed high purities, and the corresponding delipidated fractions produced using supercritical techniques offer interesting starting materials for the further production of bioactive compounds. The oat polar lipid fraction contained especially digalactosyadiacylglycerol, which was shown to have valuable functional properties in the encapsulation of probiotics.

Free Prostate-specific Antigen Forms and Kallikrein-related Peptidase 2: Tools for Prostate Cancer Diagnostics

Prostate-specific antigen (PSA) is a marker that is commonly used in estimating prostate cancer risk. Prostate cancer is usually a slowly progressing disease, which might not cause any symptoms whatsoever. Nevertheless, some cases of cancer are aggressive and need to be treated before they become life-threatening. However, the blood PSA concentration may rise also in benign prostate diseases and using a single total PSA (tPSA) measurement to guide the decision on further examinations leads to many unnecessary biopsies, over-detection, and overtreatment of indolent cancers which would not require treatment. Therefore, there is a need for markers that would better separate cancer from benign disorders, and would also predict cancer aggressiveness. The aim of this study was to evaluate whether intact and nicked forms of free PSA (fPSA-I and fPSA-N) or human kallikrein-related peptidase 2 (hK2) could serve as new tools in estimating prostate cancer risk. First, the immunoassays for fPSA-I and free and total hK2 were optimized so that they would be less prone to assay interference caused by interfering factors present in some blood samples. The optimized assays were shown to work well and were used to study the marker concentrations in the clinical sample panels. The marker levels were measured from preoperative blood samples of prostate cancer patients scheduled for radical prostatectomy. The association of the markers with the cancer stage and grade was studied. It was found that among all tested markers and their combinations especially the ratio of fPSA-N to tPSA and ratio of free PSA (fPSA) to tPSA were associated with both cancer stage and grade. They might be useful in predicting the cancer aggressiveness, but further follow-up studies are necessary to fully evaluate the significance of the markers in this clinical setting. The markers tPSA, fPSA, fPSA-I and hK2 were combined in a statistical model which was previously shown to be able to reduce unnecessary biopsies when applied to large screening cohorts of men with elevated tPSA. The discriminative accuracy of this model was compared to models based on established clinical predictors in reference to biopsy outcome. The kallikrein model and the calculated fPSA-N concentrations (fPSA minus fPSA-I) correlated with the prostate volume and the model, when compared to the clinical models, predicted prostate cancer in biopsy equally well. Hence, the measurement of kallikreins in a blood sample could be used to replace the volume measurement which is time-consuming, needs instrumentation and skilled personnel and is an uncomfortable procedure. Overall, the model could simplify the estimation of prostate cancer risk. Finally, as the fPSA-N seems to be an interesting new marker, a direct immunoassay for measuring fPSA-N concentrations was developed. The analytical performance was acceptable, but the rather complicated assay protocol needs to be improved until it can be used for measuring large sample panels.

Modulation of Signaling Molecules by Human Leucocyte Antigen B27; Special Reference to STAT1

Reactive arthritis (ReA) is an inflammatory joint disease, which belongs to the group of Spondyloarthritis (SpA). It may occur after infections with certain gram-negative bacteria such as Salmonella and Yersinia. SpAs are strongly associated with the human leucocyte antigen (HLA)-B27. Despite active research, the mechanism by which HLA-B27 causes disease susceptibility is still unknown. However, HLA-B27 has a tendency to misfold during assembly. It is possible that the misfolding of HLA-B27 could alter signaling pathways and/or molecules involved in inflammatory response in cells. We have earlier discovered that in HLA-B27-positive cells the interaction between the host and causative bacteria is disturbed. Our recent studies indicate that the expression of HLA-B27 may alter certain signaling molecules by disturbing their activation. The aim of this study was to investigate whether the expression of HLA-B27 disturbs the signaling molecules, especially the phosphorylation of transcription factor STAT1. STAT1 is an important mediator of inflammatory responses. Our results show that the phosphorylation of the STAT1 is significantly altered in HLA-B27-expressing U937 monocytic cells compared with control cells. STAT1 tyrosine 701 is more strongly phosphorylated in HLAB27- expressing cells; whereas the phosphorylation of STAT1 serine 727 is prolonged. Phosphorylation of STAT1 was discovered to be dependent on protein kinase PKR. Furthermore, we found out that the expression of posttranscriptional gene regulator HuR was altered in HLA-B27-expressing cells. We also detected that HLA-B27-positive cells secrete more interleukin 6, which is an important mediator of inflammation. These results help to understand how HLA-B27 may confer susceptibility to SpAs.

Isolation and Characterization of Ovomucin - a Bioactive Agent of Egg White

The hen’s egg is a source of new life. Therefore, it contains many biologically active compounds. In addition to being a very nutritious food and also commonly used in the food industry due to its many techno-functional properties, the egg can serve as a source of compounds used as nutra-, pharmaand cosmeceuticals. One such interesting compound is ovomucin, an egg white protein responsible for the gel-like properties of thick egg white. Previous studies have indicated that ovomucin and ovomucin-derived peptides have several different bioactive properties. The objectives of the present study were to develop isolation methods for ovomucin, to characterize the structure of ovomucin, to compare various egg fractions as sources of ovomucin, to study the effects of various dissolving methods for ovomucin, and to investigate the bioactive properties of ovomucin and ovomucin-derived peptides. A simple and rapid method for crude ovomucin separation was developed. By using this method crude ovomucin was isolated within hours, compared to the 1-2 days (including a dialysis step) needed when using several other methods. Structural characterization revealed that ovomucin is composed of two subunits, α- and β-ovomucin, as egg white protein formerly called α1-ovomucin seemed to be ovostatin. However, it might be possible that ovostatin is associated within β- and α-ovomucin. This interaction could even have some effect on the physical nature of various egg white layers. Although filtration by-product fraction was a very prominent source of both crude and β-ovomucin, process development has reduced its amount so significantly that it has no practical meaning anymore. Thus, the commercial liquid egg white is probably the best option, especially if it generally contains amounts of β-ovomucin as high as were found in these studies. Crude ovomucin was dissolved both by using physical and enzymic methods. Although sonication was the most effective physical method for ovomucin solubilisation, colloid milling seemed to be a very promising alternative. A milk-like, smooth and opaque crude ovomucin suspension was attained by using a colloid mill. The dissolved ovomucin fractions were further tested for bioactive properties, and it was found that three dissolving methods tested produced moderate antiviral activity against Newcastle disease virus, namely colloid milling, enzymatic hydrolysis and a combination of sonicaton and enzymatic hydrolysis. Moreover, trypsin-digested crude ovomucin was found to have moderate antiviral activity against avian influenza virus: both subtype H5 and H7.