Nutritional risk and status of surgical patients; the relevance of nutrition training of medical students

BACKGROUND

The prevalence of undernutrition among surgical patients is thought to be high, and negatively influencing outcomes. However, recent evidence shows the increase of overweight/obesity in hospitalised patients.

AIMS

A pilot cross-sectional study was conducted in 50 patients of a Surgical Department of the University Hospital of Santa Maria (CHLN) that aimed: 1) to assess nutritional risk and status through validated methods; 2) to explore the presence of overweight/obesity; 3) to evaluate the prevalence of metabolic risk associated with obesity.

METHODS

Nutritional risk was assessed by Malnutrition Universal Screening Tool (MUST), nutritional status by Body Mass Index (BMI), waist circumference (WC), & Subjective Global Assessment (SGA). Statistical significance was set for p < 0.05.

RESULTS

58% of patients were overweight/obese and 54% had high cardio-metabolic risk, according to waist circumference; 30% of patients had significantly lost weight (≥ 5%), whereas 28% gained weight. By MUST, 46% of patients were at low risk and 34% at high risk. By SGA, 58% patients were well nourished and 40% had moderate/severe undernutrition. A longer length of stay was associated with moderate/high risk by MUST, and undernutrition by SGA (p = 0.01).

CONCLUSIONS

Undernutrition or obesity pose surgical risks. The lack of nutrition discipline in the medical curricula, limits the multiprofessional management and a better understanding of the more adequate approaches to these patients. Further, the change in the clinical scenario argues for more studies to clarify the prevalence and consequences of sarcopenic obesity in surgical patients.

Long-lived states in an intrinsically disordered protein domain

Long-lived states (LLS) are relaxation-favored spin population distributions of J-coupled magnetic nuclei. LLS were measured, along with classical (1)H and (15)N relaxation rate constants, in amino acids of the N-terminal Unique domain of the c-Src kinase, which is disordered in vitro under physiological conditions. The relaxation rates of LLS can probe motions and interactions in biomolecules. LLS of the aliphatic protons of glycines, with lifetimes approximately four times longer than their spin-lattice relaxation times, are reported for the first time in an intrinsically disordered protein domain. LLS relaxation experiments were integrated with 2D spectroscopy methods, further adapting them for studies on proteins.

Abstract P2-10-29: Time dependent breast cancer metastasis prediction using novel biological imaging, clinico-pathological and genomic data combined with Bayesian modeling to reduce over-fitting and improve on inter-cohort reproducibility

Background: Breast cancer heterogeneity demands that prognostic models must be biologically driven and recent clinical evidence indicates that future prognostic signatures need evaluation in the context of early versus late metastatic risk prediction. The aim of our work was to identify biologically validated quantitative imaging parameters with improved correlation to clinical outcome, and to address some of the remaining obstacles for a truly robust prognostic model in clinical use.

Method: We identified 4 seed proteins (ezrin/radixin/moesin-cofilin), along with several kinases as biologically relevant subnetwork of proteins that control tumor cell motility and metastasis. Patient-derived breast cancer tumour samples were used to perform a combination of imaging methods such as Fluoresecence lifetime imaging microscopy, automated segmentation and co-localisation intensity analysis. A complexity optimized Bayesian proportional hazard regression model was performed on a total of 419 breast cancer patients to validate time dependent predictions using traditional clinicopathological, genomic and our novel optical imaging-derived parameters. An independent dataset of 300 patient samples from the Leeds Institute of Molecular Medicine is currently being evaluated, representing a large cross centre validation of our integrated model.

Results: We demonstrate that the traditional gold standard clinico-pathological variables are poor predictors for patients that survive long periods, and that their predictive significance (in terms of hazard ratios) varies significantly between two temporal cohorts where the adjuvant treatments are vastly different. Moreover, we investigate the predictive accuracy of a combined imaging/clinicopathological model compared with genomic/clinicopathological models. We demonstrate how to reduce over-fitting to help improve the performance of prognostic models. Results of an integrated model combining genomic and imaging parameters are still awaited.

Discussion: We have produced the first optical imaging-derived multivariate tumour metastatic signature, which measures underlying key biological variables involved in regulating cancer cell motility. Using Bayesian proportional hazards regression in a time-dependent manner, we highlight the inadequacies of existing prediction tools and present a model combining the clinicopathological parameters with our imaging-based metastatic signature, as an integrative reproducible prognostic tool across different temporal cohorts.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-29.

Is the proton radius a player in the redefinition of the International System of Units?

It is now recognized that the International System of Units (SI units) will be redefined in terms of fundamental constants, even if the date when this will occur is still under debate. Actually, the best estimate of fundamental constant values is given by a least-squares adjustment, carried out under the auspices of the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants. This adjustment provides a significant measure of the correctness and overall consistency of the basic theories and experimental methods of physics using the values of the constants obtained from widely differing experiments. The physical theories that underlie this adjustment are assumed to be valid, such as quantum electrodynamics (QED). Testing QED, one of the most precise theories is the aim of many accurate experiments. The calculations and the corresponding experiments can be carried out either on a boundless system, such as the electron magnetic moment anomaly, or on a bound system, such as atomic hydrogen. The value of fundamental constants can be deduced from the comparison of theory and experiment. For example, using QED calculations, the value of the fine structure constant given by the CODATA is mainly inferred from the measurement of the electron magnetic moment anomaly carried out by Gabrielse's group. (Hanneke et al. 2008 Phys. Rev. Lett. 100, 120801) The value of the Rydberg constant is known from two-photon spectroscopy of hydrogen combined with accurate theoretical quantities. The Rydberg constant, determined by the comparison of theory and experiment using atomic hydrogen, is known with a relative uncertainty of 6.6×10(-12). It is one of the most accurate fundamental constants to date. A careful analysis shows that knowledge of the electrical size of the proton is nowadays a limitation in this comparison. The aim of muonic hydrogen spectroscopy was to obtain an accurate value of the proton charge radius. However, the value deduced from this experiment contradicts other less accurate determinations. This problem is known as the proton radius puzzle. This new determination of the proton radius may affect the value of the Rydberg constant . This constant is related to many fundamental constants; in particular, links the two possible ways proposed for the redefinition of the kilogram, the Avogadro constant N(A) and the Planck constant h. However, the current relative uncertainty on the experimental determinations of N(A) or h is three orders of magnitude larger than the 'possible' shift of the Rydberg constant, which may be shown by the new value of the size of the proton radius determined from muonic hydrogen. The proton radius puzzle will not interfere in the redefinition of the kilogram. After a short introduction to the properties of the proton, we will describe the muonic hydrogen experiment. There is intense theoretical activity as a result of our observation. A brief summary of possible theoretical explanations at the date of writing of the paper will be given. The contribution of the proton radius puzzle to the redefinition of SI-based units will then be examined.