Relationships between anxiety, depression self-ratings and CHD risk factors among obese, normal and lean individuals.

Psychosomatic interactions leading to the development of Coronary Heart Disease (CHD) have yet to be clarified. This study explores further whether and how an important CHD risk factor, relative weight, affects the relationships between psychological and bioclinical parameters. A principal factorial components solution (linear procedure) and an extension of the median test (non-linear procedure) were run on the scores of self-reported anxiety (IPAT Anxiety Scale) and depression (Zung Self-rating Scale), the indices of anxiety expression style, and the bioclinical measures (systolic and diastolic blood pressure, fasting blood glucose, urea and lip concentrations). The statistical procedures were carried out separately in the six subgroups which subdivide 1,694 male volunteers to a CHD detection examination, according to age (under- and over-45 yr) and relative weight (obese, normal and lean subjects). Results indicate that the relationship between psychological and bioclinical measures are specific to the subgroup considered: they are recurrent in obese and lean individuals, and more frequent in older than in younger subjects. The composition of the first factorial component is psycho-bioclinical in the under-45 obese subgroup; the second factorial component is biopsychological in the obese and lean, under- as well as over-45-yr old, subgroups. The expression style indices and the lipid concentrations are associated when the statistical method does not presuppose linearity. Present theories on psychological and bioclinical determinants of relative weight are reported, since the experimental data upon which these theories are based parallel interestingly the results of our correlational study. Indeed, both approaches suggest that cognitive factors, operationally defined by response tendencies and anxiety expression style, are different in obese and nonobese humans, and that these differences determine psycho-bioclinical relationships which are specific to these relative weight groups. Could these mechanisms of action be specified, an important step would be made in the understanding of the CHD etiology.     

Local delivery of proteins and the use of self-assembling peptides

Self-assembling peptides are members of a new class of molecules designed for tissue engineering and protein delivery. Upon injection in a physiological environment, self-assembling peptides form stable nanofiber hydrogels. Such biocompatible nanofibers can support three-dimensional growth and differentiation of many cell types. Self-assembling peptides are promising candidates for protein delivery, because they allow non-covalent binding of proteins, tethering of proteins, or incorporation of fusion proteins. Self-assembling peptides can be designed to deliver individual proteins or multiple factors, because the building blocks comprising self-assembling peptides can be designed with great flexibility.     

Hemodynamic effects of different lung-protective ventilation strategies in closed-chest pigs with normal lungs

OBJECTIVE: The benefits of lung-protective ventilation strategies used for acute respiratory distress syndrome in subjects with normal lungs are uncertain. The purpose of this study was to investigate the hemodynamic effects of conventional lung-protective ventilation (CLPV) and high-frequency oscillatory ventilation (HFOV) in a normal lung animal model. DESIGN: Prospective laboratory investigation. SETTING: Animal laboratory in a university medical center. SUBJECTS: Seven landrace pigs (mean weight 41 kg). INTERVENTIONS: Pigs were ventilated at random conventionally with positive end-expiratory pressure 2-3 cm H2O and tidal volume 10-12 mL/kg (control), with CLPV (positive end-expiratory pressure 10 cm H2O, tidal volume 6 mL/kg), or with HFOV. Hemodynamics were analyzed after insertion of biventricular conductance catheters and a pulmonary artery catheter. MEASUREMENTS AND MAIN RESULTS: The protective strategies led to higher mean airway pressures and severe hypercapnia with acidosis, which was only significant with CLPV. Compared with control, oxygenation was worse with CLPV and HFOV. With HFOV and CLPV, mean arterial pressure, cardiac output, and stroke volume decreased significantly; pulmonary arterial elastance increased. The slope of the end-diastolic pressure volume relationship for the left and right ventricle remained unchanged (preserved ventricular function), whereas the intercept increased with both protective strategies (augmented intrathoracic pressure); left and right end-diastolic volumes decreased significantly. CONCLUSIONS: In the absence of a fluid resuscitation strategy, CLPV and HFOV caused decreased mean arterial pressure, cardiac output, and stroke volume and worsened oxygenation in this normal lung animal model. This resulted primarily from a biventricular decrease in preload.     

Self-assembling peptide nanofibers and skeletal myoblast transplantation in infarcted myocardium

Cell transplantation is currently limited by poor graft retention and survival in the postinfarction scar. Because this issue could potentially be addressed by embedding cells in bioinjectable scaffolds and boosting cell survival pathways, we induced a myocardial infarction in 72 rats to assess the effects of different self-assembling peptides with or without platelet-derived growth factor (PDGF-BB) on survival of transplanted skeletal myoblasts. Two weeks after coronary artery ligation, rats were randomized to receive in-scar injections of culture medium (controls, n = 11), self-assembling peptide (RAD16-I) nanofibers (NF, n = 9), skeletal myoblasts (n = 12), or skeletal myoblasts in combination with NF (n = 8). In separate experiments with different self-assembling peptides (RAD16-II), rats received in-scar injections of culture medium (controls, n = 6), skeletal myoblasts (n = 10), PDGF-loaded peptides (n = 7), or skeletal myoblasts (5 x 10(6)) in combination with PDGF-loaded peptides (n = 9). After 1 month, left ventricular function, as assessed by echocardiography, was not improved in either of the experimental groups compared with controls. This correlated with the failure of RAD16-I peptides or PDGF-loaded RAD16-II peptides to improve myoblast survival despite a greater angiogenesis. In vitro experiments confirmed that the number of myoblasts decreased over time when seeded on nanofiber gels. These data suggest that the optimal use of biomaterial scaffolds for survival of transplanted cells will require specific tailoring of the biomaterial to the cell type.