In Vivo Evaluation of the Biocompatibility of Surface Modified Hemodialysis Polysulfone Hollow Fibers in Rat

Polysulfone (Psf) hollow fiber membranes (HFMs) have been widely used in blood purification but their biocompatibility remains a concern. To enhance their biocompatibility, Psf/TPGS (d-α-tocopheryl polyethylene glycol 1000 succinate) composite HFMs and 2-methacryloyloxyethyl phosphorylcholine (MPC) coated Psf HFMs have been prepared. They have been evaluated for in vivo biocompatibility and graft acceptance and compared with sham and commercial membranes by intra-peritoneal implantation in rats at day 7 and 21. Normal body weights, tissue formation and angiogenesis indicate acceptance of implants by the animals. Hematological observations show presence of post-surgical stress which subsides over time. Serum biochemistry results reveal normal organ function and elevated liver ALP levels at day 21. Histological studies exhibit fibroblast recruitment cells, angiogenesis and collagen deposition at the implant surface indicating new tissue formation. Immuno-histochemistry studies show non-activation of MHC molecules signifying biocompatibilty. Additionally, Psf/TPGS exhibit most favorable tissue response as compared with other HFMs making them the material of choice for HFM preparation for hemodialysis applications

Postnatal Pancreatic Islet β Cell Function and Insulin Sensitivity at Different Stages of Lifetime in Rats Born with Intrauterine Growth Retardation

Epidemiological studies have linked intrauterine growth retardation (IUGR) to the metabolic diseases, consisting of insulin resistance, type 2 diabetes, obesity and coronary artery disease, during adult life. To determine the internal relationship between IUGR and islet β cell function and insulin sensitivity, we established the IUGR model by maternal nutrition restriction during mid- to late-gestation. Glucose tolerance test and insulin tolerance test(ITT) in vivo and glucose stimulated insulin secretion(GSIS) test in vitro were performed at different stages in IUGR and normal groups. Body weight, pancreas weight and pancreas/body weight of IUGR rats were much lower than those in normal group before 3 weeks of age. While the growth of IUGR rats accelerated after 3 weeks, pancreas weight and pancreas/body weight remained lower till 15 weeks of age. In the newborns, the fasting glucose and insulin levels of IUGR rats were both lower than those of controls, whereas glucose levels at 120 and 180 min after glucose load were significantly higher in IUGR group. Between 3 and 15 weeks of age, both the fasting glucose and insulin levels were elevated and the glucose tolerance was impaired with time in IUGR rats. At age 15 weeks, the area under curve of insulin(AUCi) after glucose load in IUGR rats elevated markedly. Meanwhile, the stimulating index of islets in IUGR group during GSIS test at age 15 weeks was significantly lower than that of controls. ITT showed no significant difference in two groups before 7 weeks of age. However, in 15-week-old IUGR rats, there was a markedly blunted glycemic response to insulin load compared with normal group. These findings demonstrate that IUGR rats had both impaired pancreatic development and deteriorated glucose tolerance and insulin sensitivity, which would be the internal causes why they were prone to develop type 2 diabetes

Prox1 Regulates the Notch1-Mediated Inhibition of Neurogenesis

During development of the spinal cord, Prox1 controls the balance between proliferation and differentiation of neural progenitor cells via suppression of Notch1 gene expression

Lysine and arginine content of proteins: Computational analysis suggests a new tool for solubility design

[Image: see text] Prediction and engineering of protein solubility is an important but imprecise area. While some features are routinely used, such as the avoidance of extensive non-polar surface area, scope remains for benchmarking of sequence and structural features with experimental data. We study properties in the context of experimental solubilities, protein gene expression levels, and families of abundant proteins (serum albumin and myoglobin) and their less abundant paralogues. A common feature that emerges for proteins with elevated solubility and at higher expression and abundance levels is an increased ratio of lysine content to arginine content. We suggest that the same properties of arginine that give rise to its recorded propensity for specific interaction surfaces also lead to favorable interactions at nonspecific contacts, and thus lysine is favored for proteins at relatively high concentration. A survey of protein therapeutics shows that a significant subset possesses a relatively low lysine to arginine ratio, and therefore may not be favored for high protein concentration. We conclude that modulation of lysine and arginine content could prove a useful and relatively simple addition to the toolkit available for engineering protein solubility in biotechnological applications

Intraocular Invasion of Ocular Surface Squamous Neoplasia Through a Corneal Wound

Purpose: We report a case of intraocular invasion of ocular surface squamous neoplasia (OSSN) through a cataract surgery wound that manifested as an anterior chamber membrane, and perform a review of the literature. Methods: An 87-year-old woman with history of an incompletely excised OSSN 10 days prior presented with decreased vision due to an anterior chamber membranous film that seemed connected to an old cataract wound. The membrane was biopsied, and histopathology revealed dysplastic squamous epithelial cells of conjunctival origin. Ten days later the tumor expanded to cover the entire iris surface, and a modified enucleation was performed. Results: Histopathology revealed invasive OSSN extending deep to the ciliary body and laterally into the anterior chamber. The patient developed a submandibular node metastasis 7 months later. Literature review revealed six cases of invasive OSSN resulting from extension through a corneal wound, with varied presentations and outcomes. Conclusion: Our case is the first to report invasive OSSN presenting as an anterior chamber membrane as a result of incomplete excision of an ocular surface malignancy adjacent to a corneal wound poses a risk for intraocular tumor extension and distant metastasis. © 2020, The Author(s)