Analysis of influencing factors on the duration of pediatric peripheral intravenous catheter.

BACKGROUND: The application of peripheral intravenous catheter has been an effective guarantee for the success of pediatric therapy. We aimed to investigate the correlative factors that impacting the duration of pediatric peripheral intravenous catheter. METHODS: From January 2017 to October 2017, 370 cases of pediatric patients in the First Hospital of Hunan University of Chinese Medicine were collected as the research object. Based on the indwelling time, the collected cases were divided into two groups, namely long time group (>72 h) and short time group (<72 h). The general data and laboratory test results of two groups were collected, and the correlation factors of indwelling time were analyzed by single factor and Logistic multiple factors. RESULTS: As the results revealed that compared with short time group, patients in long time group had statistically significant differences in puncture site, phlebitis, extravasation of blood vessels, hemoglobin, white blood cells, platelets, and 75% ethanol sterilization (p < 0.05). Logistic multivariate analysis indicated that scalp puncture was the independent protective factors that affecting the duration of pediatric peripheral intravenous catheter. Moreover, phlebitis represented the independent risk factor that influencing the indwelling time of pediatric peripheral intravenous catheter. And the differences were statistically significant (p < 0.05). CONCLUSIONS: Analyze factors influencing indwelling time of pediatric peripheral intravenous catheter and enhance the management of relevant factors are of great significance to prolong the indwelling time, reduce the pain of pediatric patients, and facilitate the clinical medication.

Collagen matrix deposition is dramatically enhanced in vitro when crowded with charged macromolecules: the biological relevance of the excluded volume effect.

The excluded volume effect (EVE) rules all life processes. It is created by macromolecules that occupy a given volume thereby confining other molecules to the remaining space with large consequences on reaction kinetics and molecular assembly. Implementing EVE in fibroblast culture accelerated conversion of procollagen to collagen by procollagen C-proteinase (PCP/BMP-1) and proteolytic modification of its allosteric regulator, PCOLCE1. This led to a 20-30- and 3-6-fold increased collagen deposition in two- and three-dimensional cultures, respectively, and creation of crosslinked collagen footprints beneath cells. Important parameters correlating with accelerated deposition were hydrodynamic radius of macromolecules and their negative charge density.

Human fibroblast matrices bio-assembled under macromolecular crowding support stable propagation of human embryonic stem cells.

Stable pluripotent feeder-free propagation of human embryonic stem cells (hESCs) prior to their therapeutic applications remains a major challenge. Matrigel™ (BD Singapore) is a murine sarcoma-derived extracellular matrix (ECM) widely used as a cell-free support combined with conditioned or chemically defined media; however, inherent xenogenic and immunological threats invalidate it for clinical applications. Using human fibrogenic cells to generate ECM is promising but currently suffers from inefficient and time-consuming deposition in vitro. We recently showed that macromolecular crowding (MMC) accelerated ECM deposition substantially in vitro. In the current study, we used dextran sulfate 500 kDa as a macromolecular crowder to induce WI-38 fetal human lung fibroblasts at 0.5% serum condition to deposit human ECM in three days. After decellularization, the generated ECMs allowed stable propagation of H9 hESCs over 20 passages in chemically-defined medium (mTEsR1) with an overall improved outcome compared to Matrigel in terms of population doubling while retaining teratoma formation and differentiation capacity. Of significance, only ECMs generated by MMC allowed the successful propagation of hESCs. ECMs were highly complex and in contrast to Matrigel, contained no vitronectin but did contain collagen XII, ig-h3 and novel for hESC-supporting human matrices, substantial amounts of transglutaminase 2. Genome-wide analysis of promoter DNA methylation states revealed high overall similarity between human ECM- and Matrigel-cultured hESCs; however, distinct differences were observed with 49 genes associated with a variety of cellular functions. Thus, human ECMs deposited by MMC by selected fibroblast lines are a suitable human microenvironment for stable hESC propagation and clinically translational settings.

Applying macromolecular crowding to enhance extracellular matrix deposition and its remodeling in vitro for tissue engineering and cell-based therapies.

With the advent of multicellular organisms, the exterior of the cells evolved dramatically from highly aqueous surroundings into an extracellular matrix and space crowded with macromolecules. Cell-based therapies require removal of cells from their crowded physiological context and propagating them in dilute culture medium to attain therapeutically relevant numbers whilst preserving their phenotype. However, bereft of their microenvironment, cells under perform and lose functionality. Major efforts currently aim to modify cell culture surfaces and build three dimensional scaffolds to improve this situation. We discuss here alternative strategies that enable cells to re-create their own microenvironment in vitro, using carbohydrate-based macromolecules as culture media additives that create an excluded volume effect at defined fraction volume occupancies. This biophysical approach dramatically enhances extracellular matrix deposition by differentiated cells and stem cells, and boosts progenitor cell differentiation and proliferation. We begin to understand how well cells really can perform ex vivo if given the chance.