https://www.selleckchem.com/products/PD-98059.html We have been using sandwich freezing of living yeast and bacteria followed by freeze-substitution for observing close-to-native ultrastructure of cells. Recently, sandwich freezing of glutaraldehyde-fixed cultured cells and human tissues have been found to give excellent preservation of ultrastructure of cells and tissues. These studies, however, have been conducted using a handmade sandwich freezing device and have been limited in a few laboratories. To spread the use of this method to other laboratories, we fabricated and commercialized a new sandwich freezing device. The new device is inexpensive, portable and sterilizable. It can be used to rapid-freeze viruses, bacteria, yeast, cultured cells and animal and human tissues to a depth of 0.2 mm if tissues are prefixed with glutaraldehyde. The commercial availability of this device will expand application of rapid freezing to wide range of biological materials.The liver plays a critical role in maintaining ammonia homeostasis. Urea cycle defects, liver injury, or failure and glutamine synthetase (GS) deficiency result in hyperammonemia, serious clinical conditions, and lethality. In this study we used a mouse model with a defect in the urea cycle enzyme ornithine transcarbamylase (Otcspf-ash) to test the hypothesis that glucagon receptor inhibition using a monoclonal blocking antibody will reduce the hyperammonemia and associated lethality induced by a high-protein diet, which exacerbates disease. We found reduced expression of glutaminase, which degrades glutamine and increased expression of GS in livers of Otcspf-ash mice treated with the glucagon receptor blocking antibody. The gene expression changes favor ammonia consumption and were accompanied by increased circulating glutamine levels and diminished hyperammonemia. Otcspf-ash mice treated with the glucagon receptor-blocking antibody gained lean and body mass and had increased survival. These data suggest tha