The use of carbohydrates as cryoprotectants is increasing. In this study the effects of incorporating polysaccharides extracted from plants and microalgae originating in northern Russia, into cryoprotectant solutions used to preserve human white blood cells were investigated. Cells in the presence of the polysaccharides were cooled to either -40°C or -80°C, using a two-step cooling process. The morphological and functional indicators of the cryopreserved leukocytes were assessed by light microscopy. When combined with glycerol, the pectin-polysaccharides Lemnan from common duckweed (Lemna minor L.) and Comaruman from marsh cinquefoil (Comarum palustre L), were capable of lowering the freezing point of the cryoprotectant solution and helped to preserve the integrity of the human white blood cell membranes at temperatures below zero. In addition, the increase in phagocytic activity of neutrophils was confirmed. In the context of the contemporary search for effective cell cryoprotectants, the results of this research demonstrate that the cryopreservation of biospecimens in a polysaccharide environment is a promising trend in applied medicine, which can be considered an alternative to traditional cryogenic nitrogen techniques.
BACKGROUND: Pectins have unique properties and great potential to become an indispensable component of cryoprotective environment for platelet freezing. OBJECTIVE: To investigate the possibility of including pectins (apple pectin AU-701, tanacetan) into the composition
of a cryoprotective solution for platelets during low-temperature storage. MATERIALS AND METHODS: Samples of platelet concentrates (PC) were frozen under the protection of complex solutions and stored in an electric freezer at -80 °C for 1 and 6 months. RESULT: The study
showed that of the basic cryoprotectants, the best effect in the preservation of PC was with dimethylacetamide (DMAC). The use of pectins as an additive to the base solution of DMAC statistically improves the preservation of PC after exposure to low temperatures (-80 ° C) for 30 and 180
days. CONCLUSIONS: We conclude that DMAC is more promising as a basis for the development of a new combined cryoprotectant for PC freezing. Moreover, the chemical structure of pectin determines the level of its cryoprotective action in relation to the preservation of PC.
Methods: Seventeen children from six centers throughout Turkey were enrolled in the study. Clinical data were retrieved from the medical records.
Results:The median age at time of diagnosis of acute hepatisis was 8.9 years (min: 5-max:17). Search for etiology revealed highly positive CMV-DNA in one patient and HCV-RNA in one patient. One other patient was found to be positive for EBV, CMV and parvovirus DNA. Besides, one patient had the diagnosis of autoimmune hepatitis. The median time from diagnosis of hepatitis to diagnosis of aplastic anemia was 30 days (min:0-max:322). Pancytopenia was simultaneously present in 5 out of 17 (29%) patients. Liver transplantation due to acute fulminant hepatitis was performed in 5 patients (29%). Aplastic anemia developed before liver transplantation in two patients and after liver transplantation in three patients. In terms of treatment for aplastic anemia; 8 patients (47%) received immunsuppressive treatment (IST) with anti-thymocyte globulin and cyclosporine. HLA identical hematopetic stem cell transplantation (HSCT) was performed in 5 patients (29%). Two patients who received IST later underwent HSCT. The median time from diagnosis of AA to IST and HSCT were 45 days (min:1-max:218) and 104 days (min:86max:1282), respectively. At the end; 9 out of 17 patients (52%) were alive, in remission and transfusion free. Those who were alive either received HSCT and/or IST, except one patient who received no treatment. Eight patients (48%) died mainly due to infectious causes. Summary/Conclusion: Although there have been limited number of patients in the present study, it was noteworthy that approximately onethird of patients presented with pancytopenia at the time of diagnosis of hepatitis. Further research is needed to investigate the effect of some etiological agents on the clinical outcome. The loss of patients who did not undergo IST and HSCT revealed once again the importance of initiating IST at the appropriate time together with donor search for HSCT in this group of patients.
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