Anne Baudot

Thermal study of simple amino-alcohol solutions.

Widely regarded as the most promising approach to long-term cryopreservation of organs for transplantation, vitrification is a process where liquid is transformed into a disordered solid state free from crystals, known as the amorphous state. The vitreous state is obtained by rapid cooling to cryogenic temperatures in the presence of antifreeze substances called cryoprotectants, such as polyalcohols, which are known to be very good vitrification agents. This work reports on the thermal properties of a new class of compounds, the amino-alcohols, studied for its similarity to the structure of the equivalent polyalcohols. We studied by differential scanning calorimetry the glass-forming tendency and stability of the amorphous state for de-ionized water solutions containing 2-amino-1-ethanol and 3-amino-1-propanol at the concentrations of 35%, 40%, 43%, and 45% (w/w). A comparison is made with previous results obtained by Mehl [Cryobiology 27 (1990) 687-688] on the same compounds under different experimental conditions. The results are also compared with those obtained by Boutron [Cryobiology 30 (1993) 87-97] for the corresponding dialcohols. A further comparison is made with a few results obtained for the 1-amino-2-propanol and the 2-amino-1-propanol tested under the same conditions.

Freezing or supercooling: how does an aquatic subterranean crustacean survive exposures at subzero temperatures?

SUMMARY Crystallization temperature (Tc), resistance to inoculative freezing (IF), ice contents, bound water, protein and glycogen body contents were measured in the aquatic subterranean crustacean Niphargus rhenorhodanensis and in the morphologically close surface-dwelling aquatic crustacean Gammarus fossarum, both acclimated at 12°C, 3°C and -2°C. Cold acclimation induced an increase in the Tc values in both species but no survival was observed after thawing. However, after inoculation at high sub-zero temperatures, cold-acclimated N. rhenorhodanensis survived whereas all others, including the 3°C and -2°C acclimated G. fossarum died. In its aquatic environment, N. rhenorhodanensis is likely to encounter inoculative freezing before reaching the Tc and IF tolerance appears as a highly adaptive trait in this species. Bound water and glycogen were found to increase in the 3°C and -2°C acclimated N. rhenorhodanensis, whereas no variation was observed in G. fossarum. Considering the hydrophilic properties of glycogen, such a rise may be correlated with the increased bound water measured in cold-acclimated N. rhenorhodanensis, and may be linked to the survival of this species when it was inoculated. The ecological significance of the survival of the aquatic subterranean crustacean to inoculative freezing is paradoxical, as temperature is currently highly buffered in its habitat. However, we assume that past geographical distribution and resulting life history traits of N. rhenorhodanensis are key parameters in the current cold-hardiness of the species.

New Approaches of Ovarian Tissue Cryopreservation from Domestic Animal Species

However, each variant of the reproductive cells has introduced their own problems, and it has been realized that many aspects of the particular physiology of the cells will dictate how they respond to cryopreservation. Both male and female gametes have acquired highly specialized structural components (essential to fertilization and development) that may respond to the freezing process in ways different from that of basic cell structures.