Amphiphilic Copolymers for Versatile, Facile, and In Situ Tunable Surface Biofunctionalization

Precision surface engineering is key to advanced biomaterials. A new platform of PEGylated styrene-maleic acid copolymers for adsorptive surface biofunctionalization is reported. Balanced amphiphilicity renders the copolymers water-soluble but strongly affine for surfaces. Fine-tuning of their molecular architecture provides control over adsorptive anchorage onto specific materials-which is why they are referred to as "anchor polymers" (APs)-and over structural characteristics of the adsorbed layers. Conjugatable with an array of bioactives-including cytokine-complexing glycosaminoglycans, cell-adhesion-mediating peptides and antimicrobials-APs can be applied to customize materials for demanding biotechnologies in uniquely versatile, simple, and robust ways. Moreover, homo- and heterodisplacement of adsorbed APs provide unprecedented means of in situ alteration and renewal of the functionalized surfaces. The related options are exemplified with proof-of-concept experiments of controlled bacterial adhesion, human umbilical vein endothelial cell, and induced pluripotent cell growth on AP-functionalized surfaces

Evaluation of pre-game hydration status, heat stress, and fluid balance during professional soccer competition in the heat

This study evaluated initial hydration status (stadium arrival urine specific gravity), fluid balance (pre- and post-game nude body weight, fluid intake, urine collection), and core temperature changes (pre-game, half-time, post-game) during a professional soccer game. We monitored 17 male players (goalies included) between stadium arrival and game end (3h), playing at 34.9°C and 35.4% relative humidity, for an average Wet Bulb Globe Temperature (WBGT) heat stress index of 31.9°C. Data are mean ± SD (range). Initial urine specific gravity (USG) was 1.018 ± 0.008 (1.003-1.036); seven players showed USG ≥ 1.020. Over the three hours, body mass (BM) loss was 2.58 ± 0.88kg (1.08-4.17kg), a dehydration of 3.38 ± 1.11%BM (1.68-5.34%BM). Sweat loss was 4448 ± 1216mL (2950-6224mL), vs. fluid intake of 1948 ± 954mL (655-4288mL). Despite methodological problems with many players, core temperatures greater than or equal to 39.0°C were registered in four players by halftime, and in nine by game’s end. Many of these players incurred significant dehydration during the game, compounded by initial hypohydration; thermoregulation may have been impaired to an extent we were unable to measure accurately. We suggest some new recommendations for soccer players training and competing in the heat to help them avoid substantial dehydration.Gatorade Sports Science Institute//Universidad de Costa Rica VI-245-A4-303UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Centro de Investigación en Ciencias del Movimiento Humano (CIMOHU

Comparative characterization of Shiga toxin type 2 and subtilase cytotoxin effects on human renal epithelial and endothelial cells grown in monolayer and bilayer conditions

Published: June 23, 2016Postdiarrheal hemolytic uremic syndrome (HUS) affects children under 5 years old and is responsible for the development of acute and chronic renal failure, particularly in Argentina. This pathology is a complication of Shiga toxin (Stx)-producing Escherichia coli infection and renal damage is attributed to Stx types 1 and 2 (Stx1, Stx2) produced by Escherichia coli O157:H7 and many other STEC serotypes. It has been reported the production of Subtilase cytotoxin (SubAB) by non-O157 STEC isolated from cases of childhood diarrhea. Therefore, it is proposed that SubAB may contribute to HUS pathogenesis. The human kidney is the most affected organ because very Stx-sensitive cells express high amounts of biologically active receptor. In this study, we investigated the effects of Stx2 and SubAB on primary cultures of human glomerular endothelial cells (HGEC) and on a human tubular epithelial cell line (HK-2) in monoculture and coculture conditions. We have established the coculture as a human renal proximal tubule model to study water absorption and cytotoxicity in the presence of Stx2 and SubAB. We obtained and characterized cocultures of HGEC and HK-2. Under basal conditions, HGEC monolayers exhibited the lowest electrical resistance (TEER) and the highest water permeability, while the HGEC/HK-2 bilayers showed the highest TEER and the lowest water permeability. In addition, at times as short as 20-30 minutes, Stx2 and SubAB caused the inhibition of water absorption across HK-2 and HGEC monolayers and this effect was not related to a decrease in cell viability. However, toxins did not have inhibitory effects on water movement across HGEC/HK-2 bilayers. After 72 h, Stx2 inhibited the cell viability of HGEC and HK-2 monolayers, but these effects were attenuated in HGEC/HK-2 bilayers. On the other hand, SubAB cytotoxicity shows a tendency to be attenuated by the bilayers. Our data provide evidence about the different effects of these toxins on the bilayers respect to the monolayers. This in vitro model of communication between human renal microvascular endothelial cells and human proximal tubular epithelial cells is a representative model of the human proximal tubule to study the effects of Stx2 and SubAB related to the development of HUS.Romina S. Álvarez, Flavia Sacerdoti, Carolina Jancic, Adrienne W. Paton, James C. Paton, Cristina Ibarra, María M. Amara

Proposition d'une nouvelle ostéotomie métatarsienne médiane: L'ostéotomie cervicale de raccourcissement axial (OCRA). Approche expérimentale comparative avec l'ostéotomie de Weil

The cervical shortening axial osteotomy, is a distal metatarsal osteotomy, preserving the joint, with a cylindrical piece of bone removed in the line of the metatarsal axis, and with the preservation of a stabilising bone block, on the head fragment. After a first mathematical and geometric analysis, this second experimental study on sawbones, was to compare Weil osteotomy, Weil osteotomy with resection of a bone slice on the proximal fragment, made after the proximal translation of the distal fragment, and the cervical shortening axial osteotomy. These were performed on 20 sawbones, divided into four groups: Weil osteotomies were performed in the first three groups: using a horizontal cut in group 1, a 10° oblique cut in group 2, and a 20° oblique cut in group 3; cervical shortening axial osteotomies were performed in group 4. In a second part, the Weil osteotomies were completed by bone slice resections on the proximal fragment. In each group, the head fragment was translated one centimeter proximally. The radiographic assessement used bony lanmarks to analyse morphological changes, and the projection of these landmarks on the horizontal line. The length, heigth, and declination angles variations were mesured. With an horizontal Weil osteotomy, we found no plantar displacement of the head, but an increased metatarsal declination angle, averaging 2.6°. In an oblique Weil osteotomy, head plantar displacement is associated with a greater metatarsal declination angle. For the 10° angle oblique oteotomy, the head's plantar displacement average 2.2 mm and the metatarsal declination angle 4.2° and for 20° angle oblique osteotomy, the head plantar displacement average 2.8 mm and the metatarsal declination angle 6.4°. The bone slice resection, made just after the proximal translation of the metatarsal head, in the Weil osteotomy, resulted in the correction of head plantar displacement and metatarsal angle modifications. For the 10° angle oblique Weil ostetomy, the head displacement is 1,8 mm dorsal, and the declination angle is reduce to 0.4°; and for an 20° oblique Weil osteotomy, the results are 2.2 mm for the head dorsal displacement, and 0.4° for the declination angle. In the shortening cervical axial osteotomy, the metatarsal head follow a dorsal displacement but also a plantar displacement secondary to the plantar bone block preserved on the distal fragment, resulting in a 1.2 mm dorsal position. The metatarsal declination angle is 1.6° greater