ABSTRACT
The correlations between various formation conditions and the membrane pore characterizations of the anodic alumina membrane were investigated for seeking the optimal conditions for the formation of anodic alumina membrane. High purity aluminum foils were used as the starting materials. The anodizations were conducted under three types of electrolytes, 3% sulfuric acid, 5% sulfuric acid and 2.7% oxalic acid, respectively, with different voltages at 0 degrees C for 48 hours. The characterizations of the pore size, the effective porosity and the pore porosity were observed and determined by scanning electron microscopy. The hydraulic conductance of the membranes was measured to confirm that the pores were open and to evaluate the permselectivity of the membranes. The experimental results showed that the ordered pore arrays were obtained for oxidation under our experimental conditions. While the forming voltage was increasing, the pore size and pore porosity increased significantly (P < 0.05), and the effective porosity decreased significantly (P < 0.05). The pore size formed with 3% sulfuric acid or 5% sulfuric acid was much smaller than that with 2.7% oxalic acid as an electrolyte. The hydraulic conductance of anodic alumina membrane that formed under our experimental condition was high than those of the membranes currently available in clinical procedures. The results suggested that the optimal conditions for the formation of anodic alumina membrane to be used in hemodialysis should be 3% or 5% sulfuric acid with 12.5 V to 17.5 V at 0 degrees C for 48 hours.
Subject(s)
Humans , Aluminum Oxide , Hemodiafiltration , Membranes , Membranes, Artificial , Nanotubes , Porosity , Renal DialysisABSTRACT
In order to determine the tolerance ability of platelet to change of osmotic pressure in solution, the isotonic fresh platelets were exposed to a series of crystal salt solutions with osmotic pressure range from 47 to 611 mOsm for 15 minutes. Then the platelets were returned to isotonic condition and kept for 15 minutes. The expressions of phosphatidylserine and CD62p were assayed in platelets. The results showed that the phosphatidylserine and CD62p expressions were increased when the osmotic pressure of solution was below 238 mOsm, but no significant rise was detected when the platelets were exposed to 611 mOsm solution. No increases of positive rate of CD62p and phosphatidylserine were detected in platelets returned to isotonic condition. It is concluded that platelets are sensitive to hypoosmotic solution and tolerated to hyperosmotic solution. Exceeding the platelet safe volume limitation may lead to injure of platelet osmosis in crystal salt solution.
Subject(s)
Humans , Blood Platelets , Metabolism , Hypotonic Solutions , Pharmacology , Isotonic Solutions , Pharmacology , Osmotic Pressure , P-Selectin , Phosphatidylserines , Saline Solution, Hypertonic , Pharmacology , Sodium Chloride , PharmacologyABSTRACT
In order to acquire freezing model of the cryopretective solution (NaCl-propylene glycol-water ternary system) for platelet, the melting points (T(f)) of this cryopretective solutions with different solute concentration and different ratio of PG mass to NaCl mass were measured by using a differential scanning calorimeter (DSC), and these experimental data were fitting by computer. An empirical equation was derived which characterized the Tf as a function of the solute concentration and the ratio of PG mass to NaCl mass inside this solution. It was concluded that the equilibrium freezing model for human platelets in this system could be used to instruct platelet cryopreserving techniques.
Subject(s)
Humans , Blood Platelets , Cryopreservation , Methods , Cryoprotective Agents , Chemistry , Pharmacology , Models, Chemical , Organ Preservation Solutions , Chemistry , Pharmacology , Propylene Glycol , Chemistry , Pharmacology , Sodium Chloride , Chemistry , Pharmacology , Temperature , Water , Chemistry , PharmacologyABSTRACT
Human platelets have distinct characters when preserved by different methods. A efficient flow cytometric assay for different preserved platelets expression of CD62p and phosphatidylserine(PS) is in dire need. Efficient flow cytometric assay for CD62p and PS expressed by preserved platelets was established and the major conditions were optimized. The platelets need not to be washed to wipe off plasma and can be labelled diredtly during the sample preparation. It is efficient for flow cytometric analysis when fresh platelet riched plasma (FPRP) was set as negative control, thrombin actived FPRP, and liquid nitrogen treated FPRP were set as positive control respectively. Gly-Pro-Arg-Pro acetate salt (GPRP) was applied to prevent platelets aggregation and fibrin formation, stabilize platelets and minimize the artificial platelets activation. This is also the key to conquer difficulty of flow cytometric quantitive analysis when platelet, Ca(2+) and plasma coexist. This flow cytometric method is specially suitable for the multi-parameter assay including PS expression for cryopreserved platelets. Minimal sample manipulation, no fixation, and GPRP application resulted in minor artifacts and good sample stability. Results suggested, this flow cytometric assay for preserved platelets is simple and efficient. In addition, the author prepared four different methods treated platelets that can be easily distinguished through this flow cytometric assay. It not only makes sure the practicability of this flow cytometric assay, but also suggests the value of the treated platelets applied in preserved platelets flow cytometric ass
Subject(s)
Humans , Blood Platelets , Metabolism , Flow Cytometry , Methods , P-Selectin , Phosphatidylserines , Reproducibility of Results , Tissue PreservationABSTRACT
The temperature of platelet intracellular ice crystal formation (IIF) is one of the most important physical parameters to instruct platelet cryopreservation. In this study, the range of temperatures for platelet IIF was measured by means of biological and physical methods. All platelet samples were graded cooling, and two samples of per 5 degrees C decrease were thawed by 2 different ways: 37 degrees C directly (T 37 degrees C) and 37 degrees C after keeping in liquid nitrogen (LN) for 2 hours. The phosphatidylserine (PS) positive rate, plasma lactate dehydrogenase (LDH) concentration and platelet aggregate rate were measured in all samples. The heat release graphs of platelets cryopreserved with or without 5% DMSO were also measured by differential scanning calorimeter (DSC). The results showed that the PS positive rates and aggregate rates in platelets and plasma LDH concentrations gradually increased in T 37 degrees C group and decreased in LN group until the arrival of -35 degrees C, and then there were no further changes of the 3 parameters. A small second heat release peak was detected at about -35 degrees C in the platelet samples cryopreserved without DMSO. It is concluded that the temperature of intracellular ice crystal formation in platelet is from -30 to -40 degrees C (-35 degrees ).
Subject(s)
Humans , Blood Platelets , Physiology , Blood Preservation , Cryopreservation , Crystallization , TemperatureABSTRACT
In order to explore the factors that affect CD62p expression in platelet during the whole course of cryopreservated platelets preparation, CD62p expression of platelet was evaluated by flow cytometry assay. The whole course of cryopreservated platelets preparation in order included whole blood collection, centrifugation for fresh platelet-rich plasma preparation, addition of dimethyl sulfoxide, and freeze in -80 degrees C refrigerator and thaw in 38 degrees C water bath. Result showed that the CD62p expressed slowly from whole blood collection to addition of dimethyl sulfoxide, but expressed abruptly after freeze and thaw and it occupied 82 per cent of the whole expression. It was concluded that the whole blood collection, centrifugation for fresh platelet enriched plasma preparation and addition of dimethyl sulfoxide were optimized in the whole course, but the damage to platelets in the whole course of cryopreservation could not be avoided. It suggests that improved techniques are needed to reduce the damage to cryopreservated platelets.
Subject(s)
Humans , Blood Platelets , Metabolism , Blood Preservation , Methods , Reference Standards , Cryopreservation , Methods , Reference Standards , Flow Cytometry , P-SelectinABSTRACT
In order to explore the permissible range of temperatures for cryopreserved platelets, each of the eleven bags of platelets with 5% dimethyl sulfoxide was divided at random into eight aliquot paired groups labeled A, B, C, D, E, F, G, and H respectively. All of the groups were stored at -80℃ for one day. The control group A was stored at -80℃ throughout the experiment, and group B, C, D, E, F, G, H were replaced to the refrigerator at -80℃ after they were stored for 4 hours at -60℃, -50℃, -40℃, -30℃, -20℃, -10℃, and 0℃ respectively. All samples were thawed to test the phosphatidylserine expression, CD62p re expression, slide platelet aggregation test(SPAT), and activated plasma clotting test(aPCT). The above items were monitored in group A hourly when group A was thawed and stored at 22℃ for 4 hours. The results showed that the permissible storage temperature of cryopreserved platelet was under -40℃, and storage at temperature from -30℃ to 0℃ was detrimental for cryopreserved platelets. No significant damages were detected when the thawed platelets were stored at 22 with a gentle shaker.