Effect of oleic acid on the properties of protein adsorbed layers at water/oil interfaces: An EPR study combined with dynamic interfacial tension measurements.

Multiphase food systems consist of complex interfacial layers where surface active molecules complete compete for adsorption and interact with one another affecting the interfacial properties and the behavior of the food systems involved. The present work focuses on the examination of interactions between proteins playing an which play an important role in milk-rich food systems (namely κ-casein and ß-lactoglobulin) and oleic acid (an anionic surfactant abundant in food systems) at the oil/water interface. An interesting feature of this system is that the molecules interacting at the interface originate from different phases and do not transfer/dissolve significantly to the other phase. The systems were examined using Electron Paramagnetic Resonance (EPR) spectroscopy and Dynamic Interfacial Tension measurements (dynamic interfacial tension and dynamic interfacial dilatational rheology). This combination of experimental methods provided the dynamics of adsorption at the interface and the mechanical properties of the interface allowing valuable insight on the interactions of the different molecules. The above information was coupled with direct information on fatty acid mobility in the oil bulk phase and indirect information on the degree of relative fatty acid/protein adsorption at the interface by EPR. Overall a synergistic effect of the protein and fatty acid on decreasing interfacial tension of the oil/water interface was evidenced. The fatty acid interacted differently with the random coil κ-casein and globular ß-lactoglobulin in terms of relative adsorption and in terms on its effect on mechanical properties. Thermal denaturation of ß-lactoglobulin affected the protein's interaction with the fatty acid due to conformational changes and exposure of non-polar sites.

Factors affecting hospital stay in psychiatric patients: the role of active comorbidity.

BACKGROUND: Research on length of stay (LOS) of psychiatric inpatients is an under-investigated issue. In this naturalistic study factors which affect LOS of two groups of patients were investigated, focusing on the impact on LOS of medical comorbidity severe enough to require referral. METHODS: Active medical comorbidity was quantified using referral as the criterion. The study sample consisted of 200 inpatients with the diagnosis of schizophrenia and 228 inpatients suffering from bipolar disorder (type I or II). Jonckheere and Mann-Whitney tests were used to estimate the influence of referrals on LOS, and regression analyses isolated variables associated with LOS separately for each group. RESULTS: Half of the patients needed one or more referrals for a non-psychiatric problem. The most common medical condition of patients with bipolar disorder was arterial hypertension. Inpatients with schizophrenia suffered mostly from an endocrine/metabolic disease - 12% of referrals were for Hashimoto's thyroiditis. A positive linear trend was found between LOS and number of referrals; the effect was greater for schizophrenia patients. The effect of referrals on LOS was verified by regression in both groups. Overall, referred patients showed greater improvement in GAF compared to controls. CONCLUSIONS: To our knowledge this was the first study to investigate physical comorbidity in psychiatric inpatients using the criterion of referral to medical subspecialties. Comorbidity severe enough to warrant referral is a significant determinant of hospital stay. This insight may prove useful in health care planning. The results show lack of effective community care in the case of schizophrenia and negative symptoms may be the cause of this. Our findings call for more attention to be paid to the general medical needs of inpatients with severe mental health and concurrent severe medical comorbidity.