China 
Africa 
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The human embryo: Vitrification Vitrification
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
Zsolt Peter Nagy, Ching-Chien Chang, Gábor Vajta
Commonly used non-permeable cryoprotectants include monosaccharides and disaccharides, sucrose, tre- halose, glucose, and galactose (41–43). Recently, sucrose has become almost a standard component of vitrification mixtures. This is true even though nearly all comparative investigations proved the superiority of trehalose. Sucrose as well as other sugars may not have any toxic effects at low temperatures, but may compromise embryo survival when applied extensively to counterbalance embryo swelling after warming (44–46), although this effect was not always dem- onstrated (47). Several polymers were also suggested for the purpose, including polyvinylpyrrolidine, polyethylene gly- col, Ficoll, dextran and polyvinyl alcohol (48–53). However, from this group, the only widely used compound is Ficoll, predominantly in combination with ethylene glycol and sucrose (54). Various forms of protein supplementation have also been used, including egg yolk, but its optically dense appearance made microscopic manipulation rather diffi- cult. High concentrations of sera of different origins as well as serum albumin preparations (55) are common additives. In the bovine model, recombinant albumin and hyaluro- nan were also effective (56). On the other hand, the use of antifreeze proteins isolated from arctic animals (57–59) has largely been abandoned. More recently, hydroxypropyl cel- lulose was investigated as a replacement for serum-derived protein for use in cryoprotectant solutions, and results from its use have been promising (60, 61).
Protein evolution revisited
Published in Systems Biology in Reproductive Medicine, 2018
Peter L. Davies, Laurie A. Graham
Antifreeze proteins (AFPs) are present in many different branches of the tree of life (Bar Dolev et al. 2016). This special type of protein was first discovered in marine fishes that must protect themselves from freezing in seawater that can reach as cold as −1.9°C (DeVries and Wohlschlag 1969). AFPs are common in insects that overwinter at sub-zero temperatures (Duman 2001). Terrestrial insects have necessarily developed more powerful AFPs with activities that can far exceed the levels seen with fish AFPs (Scotter et al. 2006). AFPs are also present in many cold-hardy plants (Bredow and Walker 2017). Paradoxically, their function here is not to prevent freezing but to inhibit the recrystallization of ice that would otherwise dehydrate plant cells and cause structural damage to the tissues as the ice crystals increased unchecked in size. AFPs are secreted by microorganisms that inhabit snow and ice (Raymond and Knight 2003; Raymond 2011). Here, their function might be to help keep fluid channels open around the cells (Duman 2001). A second function in microorganisms includes using the AFP as a domain of an adhesin to physically attach the host to ice (Guo et al. 2012).
Cryoablation: physical and molecular basis with putative immunological consequences
Published in International Journal of Hyperthermia, 2019
John G. Baust, Kristi K. Snyder, Kimberly L. Santucci, Anthony T. Robilotto, Robert G. Van Buskirk, John M. Baust
The dual cycle or repetitive freeze–thaw practice provides an inherent sensitization observed during the second freeze [1,9,16,31]. During the first freeze, the targeted nadir temperature (−40°C) is attained at a point distal from the cryoprobe. Exposure to above nadir temperatures occurs closer to the freeze margin. Cells in this region are stressed, some are partially damaged and may repair and survive. However, when cells in this region experience a second freeze-thaw excursion, increased cell death is observed. Efforts to enhance ice structure lethality have relied on the addition of high concentrations of glycine, salts and antifreeze proteins but may provide a challenge to clinical translation.
Special Issue in Honor of Gordon H. Dixon
Published in Systems Biology in Reproductive Medicine, 2018
Rod Balhorn, Peter L. Davies, Kenneth Cole Kleene, Stephen A. Krawetz, Jovita Mezquita-Pla, Rafael Oliva, J. Christopher States, Helen G. Tempest
My opportunity to work with Gordon came in 1974 as a post-doctoral fellow when GHD returned to Canada from Sussex, UK to set up a new lab at the University of Calgary’s Medical School next to the Foothills Hospital. By this time, it was realized that eukaryotic messenger RNAs had poly (A) tails and the isolation of protamine mRNA had been achieved and perfected in the GHD lab by Lashitew Gedamu. One of the collaborative projects that I worked on with Lashitew in Calgary was a study of the proteins bound to protamine mRNA that formed messenger ribonucleoprotein (mRNP) particles. My planned project as a new independent investigator and Assistant Professor at Queen’s University (Kingston, ON) in 1977 was an examination of mRNP particles in developing muscle. But a friendship formed at UBC with one of GHD’s graduate students, Choy-Leung Hew, changed all that. Choy had worked with Gordon on haptoglobins and was an expert in protein chemistry. He joined the faculty at Memorial University of Newfoundland in 1974, and soon after developed an interest in the recently discovered antifreeze proteins (AFPs) of marine fishes. Choy recruited me to the study of AFPs to assist with the molecular biology aspects because I had gained experience in mRNA isolation, cDNA synthesis, and nucleic acid sequencing from my research with GHD in Calgary. It was a fortuitous transition as AFPs have been an extremely productive field for investigating protein structure-function relationships. However, some of the most fascinating insights about AFPs are those that relate to protein evolution – the theme of the review article GHD wrote over 50 years ago that is echoed here. Our review on protein evolution features examples from the field of AFPs, but with some parallels to protamines. ‘Protein evolution revisited’ by Peter L. Davies and Laurie A. Graham.