The distribution, nature and linkage of sialic acids in skin proteins

Prevention of anastomotic stenosis for decellularized vascular grafts using rapamycin-loaded boronic acid-based hydrogels mimicking the perivascular tissue function

Abnormal proliferation of vascular smooth muscle cells (VSMCs) induces graft anastomotic stenosis, resulting in graft failure. Herein, we developed a drug-loaded tissue-adhesive hydrogel as artificial perivascular tissue to suppress VSMCs proliferation. Rapamycin (RPM), an anti-stenosis drug, is selected as the drug model. The hydrogel was composed of poly (3-acrylamidophenylboronic acid-co-acrylamide) (BAAm) and polyvinyl alcohol. Since phenylboronic acid reportedly binds to sialic acid of glycoproteins which is distributed on the tissues, the hydrogel is expected to be adherent to the vascular adventitia. Two hydrogels containing 25 or 50 mg/mL of BAAm (BAVA25 and BAVA50, respectively) were prepared. A decellularized vascular graft with a diameter of <2.5 mm was selected as a graft model. Lap-shear test indicates that both hydrogels adhered to the graft adventitia. In vitro release test indicated that 83 and 73 % of RPM in BAVA25 and BAVA50 hydrogels was released after 24 h, respectively. When VSMCs were cultured with RPM-loaded BAVA hydrogels, their proliferation was suppressed at an earlier stage in RPM-loaded BAVA25 hydrogels compared to RPM-loaded BAVA50 hydrogels. An in vivo preliminary test reveals that the graft coated with RPM-loaded BAVA25 hydrogel shows better graft patency for at least 180 d than the graft coated with RPM-loaded BAVA50 hydrogel or without hydrogel. Our results suggest that RPM-loaded BAVA25 hydrogel with tissue adhesive characteristics has potential to improve decellularized vascular graft patency.

A glycopeptide from adenocarcinoma tissue of human lung

A glycopeptide from adenocarcinoma tissue of human lung was extracted by protein digestion with papain (EC 3.4.22.2) and trypsin (EC 3.4.21.4). This component was isolated by Pevikon block electrophoresis. It possessed hexose, glucosamine, fucose, galactosamine, and sialic acid. In its carbohydrate composition and also the abundance of threonin in the peptide moiety it was quite similar to the glycoprotein from gastrointestinal tract. The physical characteristic of the two, such as their optical rotation and viscosity, were also very similar each other.

Histochemistry of complex carbohydrates in the hairy skin of the domestic pig

The hairy skin from eleven body areas of the domestic pig has been studied by means of a series of selected methods for the detection of complex carbohydrates, including peroxidase-labelled lectin-diaminobenzidine procedures. The results obtained were most distinctive in the areas where the skin accessories were involved. The complex carbohydrates in the epidermis appear to be acidic and neutral glycoproteins containing a small amount of sialic acid residues. The dermal connective tissue fibres revealed positive reactions for neutral and acidic glycoproteins with notable amounts of sialic acid residues, and for proteoglycans. In different parts of the hair follicle, neutral and acidic glycoproteins were also present, most being restricted to the connective tissue sheath and the dermal papilla. In the lower regions of the outer epithelial root sheath the epithelium contained a large amount of glycogen. The sebaceous glands reacted very weakly for neutral and acidic glycoproteins. The apocrine glands exhibited mostly neutral but also acidic glycoproteins in the secretory cells and the lumenal secretion, with substantial amounts of various saccharide residues.