Chitosan is widely known to accelerate wound healing. Therefore, various wound dressings based on chitosan have been reported. Although hydrogel-type wound dressings are suitable for moist wound healing, it is difficult to develop hydrogel-type chitosan wound dressings due to two reasons. When we prepare chitosan hydrogels, chitosan first needs to be dissolved in water. However, since chitosan dissolves only in acidic water, the resulting hydrogel is also acidic, making it unsuitable for application to wounds. In addition, the polymer dissolved in an aqueous solution needs to be cross-linked with chemical cross-linkers to form hydrogels. However, because chemical cross-linkers are highly toxic, hydrogels containing them are not suitable for medical applications. Here, we describe our chitosan hydrogels exhibiting neutral pH and containing no additives, which are prepared by freeze-thawing or autoclaving chitosan aqueous solutions without using chemical cross-linkers. ...and more
The movement to replace plastic products with environmentally friendly materials is accelerating due to the seriousness of not only global warming but also the problem of plastic waste in the oceans. Biomass resources such as trees and grasses have existed on the earth for a long time and are considered "the ultimate environmentally friendly materials" that can be metabolized by natural processes that clean up the environment. In this article, we introduce the approach of powdering and mixing biomass with cellulose derivatives to confer the property of moldability on biomass without using petroleum-based resins and to generate three-dimensional molded products by extrusion. ...and more
Hyaluronan (HA) is a central component of the extracellular matrix (ECM) in the central nervous system. Brain HA exists in two distinct forms of ECM: the diffuse ECM, which is soluble in saline and detergents, and the condensed ECM, which forms aggregates, such as perineuronal nets. Although the physiological functions of HA significantly differ depending on its size, size differences in HA have not yet been examined in the two ECM types. Recently, we established a simple method to simultaneously assess the molecular weight (MW) of HA in multiple crude biological samples. HA was purified through single-step precipitation from tissue extracts using biotinylated HA-binding protein and streptavidin-coupled magnetic beads, followed by separation on gel electrophoresis. By applying this method to HA in the mouse brain, we revealed that the condensed ECM contained higher MW HA than the diffuse ECM. Higher MW HA and lower MW HA exhibited different spatial distributions: the former was confined to perineuronal nets, while the latter was widely present throughout the brain. Furthermore, the limited degradation of HA showed that higher MW HA was required to form an insoluble HA-aggrecan complex. The present study demonstrated that the MW of HA in the brain strongly correlates with the localization and solubility of the ECM it forms. ...and more
Prostate cancer (PCa) is the most common malignant tumor in men. As the number of patients increases, the number of patients with a highly malignant treatment-resistant form of prostate cancer is increasing, which is a problem. Therefore, there is a need to develop diagnostic and therapeutic methods for malignant prostate cancer. Prostate-specific antigen tests are currently used to diagnose PCa, but they have a high rate of false positives that often require the use of invasive diagnostic interventions. Therefore, more accurate diagnostic methods are needed. The authors elucidated the expression and function of O-glycans in PCa cells that have become malignant under hormone deprivation and hypoxic conditions. In order to understand the glycan structures expressed in cells, detection with antibodies and lectins, enzymatic and chemical excision, and analysis using mass spectrometry are being used. In addition, the saccharide primer method has been developed to analyze glycans expressed in cultured cells. In this article, we will introduce the results of O-glycan analysis using the saccharide primer method in prostate cancer cells that became malignant after hormone removal or in a hypoxic environment, as well as functional analysis of these glycans. ...and more
