Fibrous biomaterials: Effect of textile topography on foreign body reaction.

Foreign Body Reaction (FBR) is a critical issue to be addressed when polyethylene terephthalate (PET) textile implants are considered in the medical field to treat pathologies involving hernia repair, revascularization strategies in arterial disease, and aneurysm or heart valve replacement. The natural porosity of textile materials tends to induce exaggerated tissue ingrowth which may prevent the implants from remaining flexible. The purpose of this study is to assess the influence of the textile topography of various woven substrates on the wetting properties of these substrates and on their in vitro interaction with mesenchymal stem cells (MSC) at 24 and 72 hr. The tests were performed both at yarn and fabric level under forced wetting and ingrowth conditions in order to replicate the mechanisms going on in vivo under blood pressure. Results demonstrate that cell proliferation is influenced by the textile wetting properties, which can be tuned at yarn and fabric level. In particular, it is shown that a satin weave obtained from porous spun yarn limits cell proliferation due to the high porosity of the yarn and the limited saturation index of the weave. Yarn and fabric saturation seems to play a predominant role in cell proliferation on textile substrates.

Central blood pressures in early chronic kidney disease: an analysis of CARTaGENE.

BACKGROUND: Vascular stiffness and advanced chronic kidney disease (CKD) are strong determinants of higher central blood pressure (BP) and are associated with high cardiovascular morbidity and mortality. Whether mild-to-moderate CKD is associated with higher central BP independently of other comorbid conditions remains uncertain. METHODS: We evaluated the central hemodynamic profile [central systolic BP, central pulse pressure (PP), augmentation index, PP amplification, augmented pressure] of Stage 3 CKD patients and compared it with participants with estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m 2 in the CARTaGENE populational cohort through propensity score matching and multivariate regression analyses. RESULTS: Of the 20 004 participants, 13 114 had valid pulse wave analysis and eGFRs >30 mL/min/1.73 m 2 , of which 515 had Stage 3 CKD. These 515 patients had significantly higher peripheral systolic BP (127 ± 16 versus 125 ± 15 mmHg, P = 0.01) and central PP (43.0 ± 11.4 versus 39.7 ± 10.0 mmHg, P <0.001) than the control group (eGFR >60 mL/min/1.73 m 2 ). Propensity score matching allowed the creation of 500 pairs with similar clinical characteristics. In this matched cohort, central BPs were similar in Stage 3 CKD patients compared with controls (central PP 42.9 ± 11.3 versus 43.7 ± 11.3 mmHg, P = 0.3). Multivariate analysis using data from all patients also found that the higher central hemodynamic readings found in Stage 3 CKD patients disappeared after adjusting for comorbid conditions. In a subset of 609 participants in whom albuminuria levels were measured, urine albumin excretion was not independently associated with higher central hemodynamic indices. CONCLUSION: In this large cohort from the general population, early CKD and albuminuria was not independently associated with detrimental central hemodynamic parameters.

Heart rate dependent and independent effects of beta-blockers on central hemodynamic parameters: a propensity score analysis.

OBJECTIVES: Central hemodynamic parameters are better predictors of the cardiovascular burden than peripheral blood pressure (BP). Beta-blockers are known to reduce central BP to a lesser extent than peripheral BP, a hypothesized mechanistic consequence of heart rate (HR) reduction. METHODS: The association between beta-blocker use, HR and central hemodynamics indices was studied in treated hypertensive participants of the CARTaGENE study using propensity score analyses and multivariate linear regressions. RESULTS: Of the 20 004 participants, 2575 were treated hypertensive patients with valid pulse wave analysis. Using propensity score analyses, beta-blocker users (n = 605) were matched to nonusers having similar clinical characteristics with (Model 1) and without (Model 2) adjustment for HR. This resulted in 457 and 510 pairs with adequate balance, except for a HR difference in Model 2 (62.5 ±â€Š10.5 vs. 70.4 ±â€Š11.5 bpm, p < 0.001). In Model 1, the central pulse pressure (PP) was 46.5 ±â€Š12.9 mmHg with beta-blocker compared with 45.4 ±â€Š11.0 mmHg without (p = 0.045). PP amplification, augmentation index and augmented pressure were also less favorable with the use of beta-blocker. The HR difference in Model 2 further increased the difference in central PP observed with beta-blocker to 46.5 ±â€Š13.0 vs. 43.3 ±â€Š11.3 without (p < 0.001). These findings were similar when atenolol, metoprolol and bisoprolol were assessed separately using multivariate linear regression models. CONCLUSION: This study shows that the unfavorable central hemodynamic profile of beta-blocker has both HR-dependent and HR-independent components that are similar for all frequently used ß1-selective beta-blocker.

Retrospective analysis of the predictive factors of renal function loss after uninephrectomy in patients with chronic kidney disease G3 to G5.

BACKGROUND: The rapid increase in glomerular filtration rate in a normal contralateral kidney after uninephrectomy is well known in living kidney donors but much less well described in chronic kidney disease (CKD). The purpose of this study is to determine the magnitude of this initial compensatory capacity in (CKD) groups 3 to 5 (G3 to G5) patients undergoing uninephrectomy and the clinical factors predicting it. This is a retrospective study of all cases (142) of uninephrectomy in patients with estimated glomerular filtration rate (eGFR; with MDRD equation) <60 ml/min/1.73 m(2), between 2003 and 2010, in two University of Montreal-affiliated teaching hospitals. METHODS: Baseline eGFR, patients' comorbidities, and surgical characteristics and complications were noted. The change of eGFR after nephrectomy was evaluated; moreover, the expected post-op eGFR, i.e. without compensation by the contralateral kidney following surgery, was estimated in a sub-group of patients who had a preoperative renal scintigraphy and compared to the actual eGFR at hospital discharge. RESULTS: The mean change of eGFR from baseline to hospital discharge was -5 ± 12 ml/min/1.73 m(2) (-11 %; 95 % CI -16 to -6 %; P < 0.001). In univariate and multivariate analyses, baseline eGFR did not influence significantly these results. However, in the multivariate model, radical nephrectomy vs. partial nephrectomy and preoperative hypertension predicted a worse renal outcome. In the sub-group of patients with preoperative renal scintigraphy, the actual eGFR at hospital discharge was also higher than expected from the renal split function (13 ml/min/1.73 m(2); 95 % CI 10 to 16; P < 0.001). CONCLUSIONS: After uninephrectomy, the contralateral kidney in patients with CKD G3 to G5 still has a clinically significant initial compensatory capacity. The compensation is statistically smaller if the patient had hypertension or a radical uninephrectomy. This initial compensation is rapid and most probably haemodynamic (hyperfiltration). However, most of the included patients had a CKD G3, limiting the strength of the conclusion for the G4 toG5 patients; the length of observation covers the early postoperative period, i.e. less than 2 weeks, in more than half of the cohort.

MISE EN CONTEXTE: L'accroissement rapide du débit de filtration glomérulaire du rein controlatéral à la suite d'une uninéphrectomie (uniNPX) est bien connu pour les donneurs de rein vivants, mais est beaucoup moins bien documenté dans le cas des patients souffrant d'une insuffisance rénale chronique (IRC). OBJECTIF: L'étude avait pour objectif principal de déterminer à quel point la capacité de compensation initiale du rein controlatéral est maintenue chez les patients souffrant d'IRC de stade 3 à 5 après une NPX et quels facteurs cliniques sont susceptibles d'aider à prévoir la perte d'activité fonctionnelle du rein. CADRE ET TYPE D'ÉTUDE: Il s'agit d'une étude rétrospective de 142 cas de NPX pratiquées entre 2003 et 2010 au sein de deux centres hospitaliers universitaires affiliés à l'Université de Montréal, sur des patients présentant un débit de filtration glomérulaire estimé (DFGe) par l'équation MDRD, inférieur à 60 ml/min/1.73 m2. MÉTHODE: La mesure du débit de filtration glomérulaire préopératoire, les maladies concomitantes inscrites au dossier, les particularités de la chirurgie ainsi que les complications survenues par la suite, ont été notées pour chaque patient. La variation du DFG a été évaluée après la chirurgie. De plus, le DFG post-op attendu, calculé en ne tenant pas en compte la compensation offerte par le rein controlatéral après la chirurgie, a été estimé pour un sous-groupe de patients qui avaient subi une scintigraphie rénale préopératoire et comparé à la mesure du DFG faite au moment de la sortie de l'hôpital. RÉSULTATS: La variation moyenne du DFG entre les mesures prises avant la chirurgie et celles prises lors de la sortie de l'hôpital était de −5 ± 12 ml/min/1.73 m2 (−11 %; 95 % IC −16 % à −6 %; P < 0.001). Le DFG initial n'a en aucun cas influencé significativement les résultats qu'ils aient été analysés par un modèle d'analyse unidimensionnelle ou par un modèle d'analyse à variables multiples. Toutefois, dans le second type d'analyse, la présence d'hypertension préopératoire et le type de néphrectomie pratiquée (partielle ou radicale) ont laissé entrevoir de moins bons résultats. Enfin, le DFG mesuré à la sortie de l'hôpital chez les patients qui avaient subi une scintigraphie rénale préopératoire était plus élevé que le DFG prévu, calculé à partir de la division de la fonction rénale (13 ml/min/1.73 m2; 95 % IC 10 à 16; P < 0.001). CONCLUSIONS ET LIMITES DE L'ÉTUDE: À la suite d'une néphrectomie, le rein controlatéral des patients atteints d'insuffisance rénale chronique de stade 3 à 5 possède toujours une capacité compensatoire significative du point de vue clinique. Par contre, la compensation est moindre si le patient souffre d'hypertension avant la chirurgie ou lorsqu'il subit une uniNPX radicale, elle est également rapide et probablement hémodynamique (hyperfiltration). Il importe également de noter que la majorité des patients ayant participé à l'étude avait une IRC de stade 3 et que ceci ne permet pas de tirer des conclusions sans équivoque pour les patients de stades 4 et 5. De plus, les observations se sont déroulées sur une très courte période, moins de deux semaines pour plus de la moitié de la cohorte, immédiatement après la chirurgie.

Rheological properties of silica dispersions stabilized by stereoregular poly(methyl methacrylate).

The adsorption of stereoregular polymers and its effect on the conformation and dynamics of the polymer at interfaces are only poorly understood. 1H NMR has revealed a lowering of the peaks assigned to isotactic sequences whatever the PMMA tacticity, which provides evidence of stereospecific adsorption of the isotactic segments on silica. Entropic factors are therefore assumed to control the configuration of the adsorbed layer. Tacticity-dependent rheological behavior is revealed by dynamic investigations carried out on silica dispersions. The driving forces likely to induce the stereoselective adsorption and tacticity-dependent rheology of suspensions are discussed.