Characterization of Long-term Cold Storage Effects on Platelet Hemostatic Function and GPIbα Glycan Composition

Platelet transfusion is an important, life saving therapy for treatment of thrombocytopenia and active bleeding related complications. To be clinically effective, transfused platelets must have sufficient ability to mediate hemostatic regulatory function and circulate. Current practices for storing platelet concentrates (PCs) for transfusion therapy are suboptimal. PCs are standardly stored at room temperature (22-24C°) as cold exposure (4-6C°) irreversibly compromises platelets, making them susceptible to rapid clearance from circulation. Room temperature (RT) storage increases risks of bacterial contamination, thus PCs are restricted to a shelf life of 5 days leading to PC shortages and waste. Cold storage of platelets is an increasingly desirable alternative as risks of bacterial contamination are reduced and PC shelf life extended with cold storage. This study re-evaluates the consequences of long-term (5 day) RT and cold storage on platelet functionality to better inform development of current platelet storage standards. Specifically platelet hemostatic function and platelet GPIbα receptor glycan exposure, as it relates to cold-induced platelet clearance, was evaluated by flow cytometric analysis and aggregometry at select time points. The results of this study demonstrate cold storage better preserves platelet hemostatic functionality than RT storage, thus supporting cold storage as a desirable condition to optimize for PC storage. Furthermore results from this study support a recently proposed, novel, long-term storage platelet clearance mechanism and provide insight into the GPIbα receptor glycan exposure dynamics of long-term RT and cold stored platelets

Detection of Methoxymethanol as a Photochemistry Product of Condensed Methanol

We report the identification of methoxymethanol (CH3OCH2OH) as a photochemistry product of condensed methanol (CH3OH) based on temperature-programmed desorption studies conducted following photon irradiation at energies below the ionization threshold (9.8 eV) of condensed methanol. The first detection of methoxymethanol in the interstellar medium was reported in 2017 based on data from Bands 6 and 7 from the Atacama Large Millimeter/submillimeter Array (ALMA). The cosmic synthesis of “complex” organic molecules such as methyl formate (HCOOCH3), dimethyl ether (CH3OCH3), acetic acid (CH3COOH), ethylene glycol (HOCH2CH2OH), and glycolaldehyde (HOCH2CHO) has been attributed to UV photolysis of condensed methanol found in interstellar ices. Experiments conducted in 1995 demonstrated that electron-induced radiolysis of methanol cosmic ice analogues yields methoxymethanol. In three recent publications (2016, 2017, and 2018), methoxymethanol was considered as a potential tracer for reactions induced by secondary electrons resulting from the interaction of cosmic rays with interstellar ices. However, the results presented in this study suggest that methoxymethanol can be formed from both radiation chemistry and photochemistry of condensed methanol

Condensed-Phase Photochemistry in the Absence of Radiation Chemistry

We report post-irradiation photochemistry studies of condensed ammonia using photons of energies below condensed ammonia’s ionization threshold of ~ 9 eV. Hydrazine (N2H4), diazene (also known as diimide and diimine) (N2H2), triazane (N3H5), and one or more isomers of N3H3 are detected as photochemistry products during temperature-programmed desorption. Product yields increase monotonically with (1) photon fluence and (2) film thickness. In the studies reported herein, the energies of photons responsible for product formation are constrained to less than 7.4 eV. Previous post-irradiation photochemistry studies of condensed ammonia employed photons sufficiently energetic to ionize condensed ammonia and initiate radiation chemistry. Such studies typically involve ion-molecule reactions and electron-induced reactions in addition to photochemistry. Although photochemistry is cited as a dominant mechanism for the synthesis of prebiotic molecules in interstellar ices, to the best of our knowledge, ours is one of the first astrochemically-relevant studies that has found unambiguous evidence for condensed-phase chemical synthesis induced by photons in the absence of ionization