Definition, diagnosis and treatment of oligometastatic oesophagogastric cancer: A Delphi consensus study in Europe.

Local treatment improves the outcomes for oligometastatic disease (OMD, i.e. an intermediate state between locoregional and widespread disseminated disease). However, consensus about the definition, diagnosis and treatment of oligometastatic oesophagogastric cancer is lacking. The aim of this study was to develop a multidisciplinary European consensus statement on the definition, diagnosis and treatment of oligometastatic oesophagogastric cancer. In total, 65 specialists in the multidisciplinary treatment for oesophagogastric cancer from 49 expert centres across 16 European countries were requested to participate in this Delphi study. The consensus finding process consisted of a starting meeting, 2 online Delphi questionnaire rounds and an online consensus meeting. Input for Delphi questionnaires consisted of (1) a systematic review on definitions of oligometastatic oesophagogastric cancer and (2) a discussion of real-life clinical cases by multidisciplinary teams. Experts were asked to score each statement on a 5-point Likert scale. The agreement was scored to be either absent/poor (<50%), fair (50%-75%) or consensus (≥75%). A total of 48 experts participated in the starting meeting, both Delphi rounds, and the consensus meeting (overall response rate: 71%). OMD was considered in patients with metastatic oesophagogastric cancer limited to 1 organ with ≤3 metastases or 1 extra-regional lymph node station (consensus). In addition, OMD was considered in patients without progression at restaging after systemic therapy (consensus). For patients with synchronous or metachronous OMD with a disease-free interval ≤2 years, systemic therapy followed by restaging to consider local treatment was considered as treatment (consensus). For metachronous OMD with a disease-free interval >2 years, either upfront local treatment or systemic treatment followed by restaging was considered as treatment (fair agreement). The OMEC project has resulted in a multidisciplinary European consensus statement for the definition, diagnosis and treatment of oligometastatic oesophagogastric adenocarcinoma and squamous cell cancer. This can be used to standardise inclusion criteria for future clinical trials

Oscillatory Water Sorption Test for Determining Water Uptake Behavior in Bread Crust

In this work, water sorption kinetics of bread crust are described using an oscillatory sorption test in combination with a Langmuir type equation. Both kinetic and thermodynamic information could be obtained at the same time. An advantage of applying a Langmuir type equation for a quantitative description of the water uptake kinetics is that no prior knowledge is necessary with respect to shape and surface area of the sample. It was shown that adsorption and desorption of water to the bread crust particle surface is much faster than the experimental time used (15 min at minimum). From this, we may conclude that diffusion of water into the solid matrix is the rate-limiting step in the water sorption process. The method also allows one to calculate a Gibbs free energy. The method is suitable for use up to relative humidities of 60%

Crystallinity changes in wheat starch during the bread-making process: starch crystallinity in the bread crust

The crystallinity of starch in crispy bread crust was quantified using several different techniques. Confocal scanning laser microscopy (CSLM) demonstrated the presence of granular starch in the crust and remnants of granules when moving towards the crumb. Differential scanning calorimetry (DSC) showed an endothermic transition at 70 degrees C associated with the melting of crystalline amylopectin. The relative starch crystallinity, as determined by X-ray and DSC, from different types of breads was found to lie between 36% and 41 % (X-ray) and between 32% and 43 % (DSC) for fresh bread crust. Storage of breads in a closed box (22 degrees C) for up to 20 days showed an increase in crust crystallinity due to amylopectin retrogradation both by X-ray and DSC. However, DSC thermograms of 1-day old bread crust showed no amylopectin retrogradation and after 2 days storage, antylopectin retrogradation in the crust was hardly detectable. C-13 CP MAS NMR was used to characterize the physical state of starch in flour and bread crumb and crust. The intensity of the peaks showed a dependence on the degree of starch gelatinization. Comparison of the results for two different types of bread showed that the baking process influenced the extent of starch crystallinity in the bread crust. Antylopectin retrogradation, which is the main process responsible for the staling of bread crumb, cannot be responsible for crispness deterioration of the crust as amylopectin retrogradation upon storage of breads could only be measured in the crust after 2 days storage. Under the same conditions loss of bread crust crispness proceeds over shorter times

Water sorption and transport in dry crispy bread crust

Water sorption and dynamical properties of bread crust have been studied using gravimetric sorption experiments. Water uptake and loss were followed while relative humidity (RH) was stepwise in- or decreased (isotherm experiment) or varied between two adjusted values (oscillatory experiment). Experimental results were compared with the Fickian diffusion model and empirical models like the exponential and power-law model. Sorption curves of isotherm experiments could be best described by the Fickian diffusion model for low RH and by the exponential model for large RH. Isotherm equilibrium values could be best described by the GAB equation. Transport rates depend on moisture content and show a maximum around RH=70%. Adsorption and desorption curves from oscillatory sorption experiments could be described best by the exponential model. From comparison of experimental sorption curves and the power-law model for short times it followed for all bread crust that the diffusional coefficient n is close to one. Normally this is associated to so-called case II diffusion and water transport that is limited by relaxation of the solid material. However, additional observations suggest that this may not be a valid explanation and that a kinetic barrier for water transfer to the solid matrix may explain the observed exponential behavio

Water Uptake Mechanism in Crispy Bread Crust

Crispness is an important quality characteristic of dry solid food products such as crispy rolls. Its retention is directly related to the kinetics of water uptake by the crust. In this study, a method for the evaluation of the water sorption kinetics in bread crust is proposed. Two different sorption experiments were used: an oscillatory sorption test and a sorption test in which the air relative humidity (RH) was increased stepwise. These two experiments had different time scales, which made it possible to get a better understanding of the mechanisms involved. Results show that the adsorption and desorption dynamics of the oscillatory sorption test could be described by a single exponential in time. The water uptake rate (k) was one of the fitting parameters. A maximum in the water uptake rate was found for a RH value between 50 and 70%. The rate parameters of the experiment where RH was increased stepwise were around a factor 10 lower than those derived from oscillatory sorption experiments. This is an important factor when designing experiments for the determination of water uptake rates. In addition, also a parameter describing the time dependence of the rate parameters of the oscillatory sorption experiment was calculated (C), again by fitting a single exponential to the rate parameters. C was in the same range as the rate parameter of the isotherm experiment. This indicates that different (relaxation) processes are acting at the same time in the bread crust during water uptake

Water Uptake Mechanism in Crispy Bread Crust

Crispness is an important quality characteristic of dry solid food products such as crispy rolls. Its retention is directly related to the kinetics of water uptake by the crust. In this study, a method for the evaluation of the water sorption kinetics in bread crust is proposed. Two different sorption experiments were used: an oscillatory sorption test and a sorption test in which the air relative humidity (RH) was increased stepwise. These two experiments had different time scales, which made it possible to get a better understanding of the mechanisms involved. Results show that the adsorption and desorption dynamics of the oscillatory sorption test could be described by a single exponential in time. The water uptake rate (k) was one of the fitting parameters. A maximum in the water uptake rate was found for a RH value between 50 and 70%. The rate parameters of the experiment where RH was increased stepwise were around a factor 10 lower than those derived from oscillatory sorption experiments. This is an important factor when designing experiments for the determination of water uptake rates. In addition, also a parameter describing the time dependence of the rate parameters of the oscillatory sorption experiment was calculated (C), again by fitting a single exponential to the rate parameters. C was in the same range as the rate parameter of the isotherm experiment. This indicates that different (relaxation) processes are acting at the same time in the bread crust during water uptake

Protein Concentration and Protein-Exposed Hydrophobicity as Dominant Parameters Determining the Flocculation of Protein-Stabilized Oil-in-Water Emulsions

DLVO theory is often considered to be applicable to the description of flocculation of protein-stabilized oil-in-water emulsions. To test this, emulsions made with different globular proteins (ß-lactoglobulin, ovalbumin, patatin, and two variants of ovalbumin) were compared under different conditions (pH and electrolyte concentration). As expected, flocculation was observed under conditions in which the zeta potential is decreased (around the isoelectric point and at high ionic strength). However, the extent of flocculation at higher ionic strength (>50 mM NaCl) decreased with increasing protein-exposed hydrophobicity. A higher exposed hydrophobicity resulted in a higher zeta potential of the emulsion droplets and consequently increased stability against flocculation. Furthermore, the addition of excess protein strongly increased the stability against salt-induced flocculation, which is not described by DLVO theory. In the protein-poor regime, emulsions showed flocculation at high ionic strength (>100 mM NaCl), whereas emulsions were stable against flocculation if excess protein was present. This research shows that the exposed hydrophobicity of the proteins and the presence of excess protein affect the flocculation behavior

Protein Concentration and Protein-Exposed Hydrophobicity as Dominant Parameters Determining the Flocculation of Protein-Stabilized Oil-in-Water Emulsions

DLVO theory is often considered to be applicable to the description of flocculation of protein-stabilized oil-in-water emulsions. To test this, emulsions made with different globular proteins (ß-lactoglobulin, ovalbumin, patatin, and two variants of ovalbumin) were compared under different conditions (pH and electrolyte concentration). As expected, flocculation was observed under conditions in which the zeta potential is decreased (around the isoelectric point and at high ionic strength). However, the extent of flocculation at higher ionic strength (>50 mM NaCl) decreased with increasing protein-exposed hydrophobicity. A higher exposed hydrophobicity resulted in a higher zeta potential of the emulsion droplets and consequently increased stability against flocculation. Furthermore, the addition of excess protein strongly increased the stability against salt-induced flocculation, which is not described by DLVO theory. In the protein-poor regime, emulsions showed flocculation at high ionic strength (>100 mM NaCl), whereas emulsions were stable against flocculation if excess protein was present. This research shows that the exposed hydrophobicity of the proteins and the presence of excess protein affect the flocculation behavior

Effect of Glycation on the Flocculation Behavior of Protein-Stabilized Oil-in-Water Emulsions

Glycation of proteins by the Maillard reaction is often considered as a method to prevent flocculation of protein-stabilized oil-in-water emulsions. The effect has been suggested, but not proven, to be the result of steric stabilization, and to depend on the molecular mass of the carbohydrate moiety. To test this, the stabilities of emulsions of patatin glycated to the same extent with different mono- and oligosaccharides (xylose, glucose, maltotriose, and maltopentaose) were compared under different conditions (pH and electrolyte concentration). The emulsions with non-modified patatin flocculate under conditions in which the zeta potential is decreased (around the iso-electric point and at high ionic strength). The attachment of monosaccharides (i.e., glucose) did not affect the flocculation behavior. Attachment of maltotriose and maltopentaose (Mw > 500 Da), on the other hand, provided stability against flocculation at the iso-electric point. Since the zeta potential and the interfacial properties of the emulsion droplets are not affected by the attachment of the carbohydrate moieties, this is attributed to steric stabilization. Experimentally, a critical thickness of the adsorbed layer required for steric stabilization against flocculation was found to be 2.29–3.90 nm. The theoretical determination based on the DLVO interactions with an additional steric interaction coincides with the experimental data. Hence, it can be concluded that the differences in stability against pH-induced flocculation are caused by steric interactions

Relations between sensorial crispness and molecular mobility of model bread crust and its main components as measured by PTA, DSC and NMR

Consumer appreciation of brittle cellular foods, like bread crusts, depends on textural properties such as crispness. This crispy character is lost above a certain water activity. It is not known what exactly is happening in these crusts when water enters. So is it unclear whether it is the change in the starch or the gluten that initiates the loss of crispness with ageing time. In this paper the effect of water on the glass transition of model bread crusts was studied using two complementary techniques: phase transition analysis (PTA) and temperature modulated differential scanning calorimetry (TMDSC). The mobility of water was studied with nuclear magnetic resonance (NMR). The results were compared with sensory data. Bread crusts prepared with different types of flour were tested to evaluate the effect of flour composition on the crispness of model crusts equilibrated at different relative humidities. In addition the single flour components starch and gluten were studied. Sensory crispness scores decreased with increasing aw from 0.55 upwards. At aw 0.70 sensory crispness was completely lost. Both DSC and PTA showed a transition point at an aw of 0.70-0.75. NMR gave a transition point in the mobility of the protons of water at aw 0.58. This supports the hypothesis that loss of crispness starts as a result of processes at a molecular level, before the macroscopic glass transition. This also suggests that the presence of water that is not directly attached to the solid matrix causes the loss of crispness at low aw. At higher aw increased mobility of the macromolecules will start to play a role. NMR experiments with the separate flour components indicate that the T2 transition point in starch samples occurs at a lower RH than for gluten. This could imply that starch loses crispness at lower aw than gluten. Increased mobility of small components and side chains might induce increased energy dissipation upon deformation of the material resulting in less available energy for fracture propagation and with that in a less crispy product