Inside quality control for whole blood preservation performed at blood transfusion compatibility testing laboratory / 中国实验血液学杂志

This study was aimed to establish the technique for preparation and storage of internal quality control pro-ducts by using existing blood sample resources of blood transfusion compatibility testing laboratory. 24 healthy blood donors with group A and RhD-positive were randomly selected, and 4 ml venous blood from these donors were collected, respectively. Based on the use of anticoagulant type, whether to add red blood cell preservation solution and the samples stored at room temperature for 1 or 2 hours daily, 24 specimens were randomly divided into 8 groups by using factorial design methodology. All samples in tube with cap were stored at 4 degrees C, and placed at room temperature for 1 or 2 hours daily. ABO, RhD blood group (recorded on the agglutination strength of the forward and reverse typing), IgM anti-B antibody titer, and free hemoglobin concentration in the supernatant for all samples were detected at 0, 7, 14, 21, 28, 35 days of products preservation. The results indicated that the red blood cell damage from the group used anticoagulants ACD-B and added the MAP red blood cell preservation solution and placed at room temperature 1 hour daily (recorded as A2B2C1 group) was kept minimal, and FHb concentration and FHb increments at each time point were the lowest (p < 0.01), the FHb concentration on 35th day was only (24.5 +/- 84.5) mg/L. There was no significant change of A antigen, D antigen and IgM anti-B antibody response activity and stability in A2B2C1 group during storage for 35 days (p > 0.05). In conclusion, blood transfusion compatibility testing laboratory can use A2B2C1 program established by this study to prepare relatively stable modified whole blood internal quality control products in the existing conditions, which can be effectively preserved and meet the requirements of internal quality control for blood transfusion compatibility testing.

The effect of leukocyte depletion by filtration on the quality of apheresis platelets / 中国实验血液学杂志

This study was aimed to investigate the effect of leukocyte depletion by filtration on the quality of apheresis platelets. 20 units of donor apheresis platelets were randomly selected and were preserved with agitation at 20 - 24 degrees C for 24 - 96 hours, then were filtered on polyester flatbed filters. The platelet concentration, mean platelet volume (MPV), volume of apheresis platelets, leukocyte count, pH value, lactate dehydrogenase (LDH) concentration, K(+) concentration and CD62p expression level on surface of platelet membrane, were detected before and after filtration, as well as the rate of leukocyte depletion and platelet loss were calculated. The results showed that the leukocyte count after filtration was remarkably lower than that before filtration (p < 0.001), and the rate of leukocyte depletion was 99.97%. Platelet loss was approximately 8%, and obviously lower than that of the national standard (p < 0.001). MPV, pH value, K(+) and LDH concentration were not significantly different before and after filtration. Compared with platelets before filtration, CD62p expression level after filtration slightly decreased (p > 0.05). CD62p expression on surface of platelet membrane in perfusion fluid obtained from filter plate was obviously higher than that before filtration (p < 0.05). MA of platelet after filtration slightly decreased (p > 0.05). It is concluded that leukocyte and partial activated platelets can be removed efficiently by using polyester flatbed filters, and platelet loss is very low. Filtration does not adversely affect coagulation activity of the platelets in vitro. Apheresis platelets after filtration can fulfil quality requirements to prevent infection of cytomegalovirus and HLA alloimmunization.

Establishment of genotyping method for fetal ABO group from pregnant maternal peripheral blood / 中国实验血液学杂志

This study was aimed to establish a genotyping method to detect ABO group gene of fetus from peripheral blood of pregnant women for prenatal diagnosis of hemolytic disease of newborn (HDN) resulting from ABO blood group incompatibility. 4 pairs of primers were designed according to ABO blood group gene DNA and mRNA sequences. 20 plasma DNA samples from healthy donors were extracted and amplified to explore the best conditions for plasma DNA extraction and PCR amplification. The O group plasma DNA was mixed with A group or B group plasmas by the ratios of 1:1, 2:1, 4:1, 8:1, 10:1, 20:1, 40:1, 100:1 to simulate the status of mixed ABO gene from pregnant maternal blood and to establish the mixed blood group ABO genotyping technology. The pregnant maternal blood samples with more than 30 weeks of gestation were selected for detecting the fetal ABO blood group genotype. The blood samples should be taken as possible as after birth for identification of ABO blood group and evaluation of sensitivity and accuracy of fetal ABO blood group genotyping technology through peripheral blood of pregnant women. The results indicated that the minimal amount of template DNA from single blood plasma for accuracy identification was at least about 0.625 ng, the DNA amount extracted from 500 microl of plasma could meet the requirement for PCR amplification. When the proportion of O group plasma DNA in mixed plasma DNA was <or=10, the non-O group gene could be accurately detected. Among 14 peripheral blood samples from O-group pregnant women, the non-O group gene was amplified in 9 samples; the non-O group gene was not amplified in 5 samples. The identification of peripheral blood ABO group for 5 newborns using serologic method showed that the A group 3 cases, B group 2 cases, O group 1 case, which consisted with genotyping results with consistent rate 100%. It is concluded that in middle and late pregnancy the fetal ABO group gene can be detected accurately by means of established fetal ABO group gene extraction and typing technology, that provides some guidances for the prenatal diagnosis and prevention of HDN.

Application of thrombelastography in evaluation of platelet function during storage / 中国实验血液学杂志

This study was aimed to explore changes of platelet function in vitro during storage by thrombelastography (TEG). 12 units plateletpheresis were randomly selected and stored at 20 to 24 degrees C with agitation. Thrombelastography variable parameters R, K values and maximal amplitude (MA) were measured on 1, 2, 3, 4, 5 days of platelet storage. Platelet concentration, mean platelet volume (MPV), hypotonic shock response (HSR), CD62p expression and CD62p reexpression on platelet surface were detected at the same time. Changes of platelet function in virto were systematically evaluated by above-mentioned indexes. The results showed that MPV augmented slightly with prolongation of preserved time (p > 0.05), and CD62p expression on platelet surface increased remarkably (p < 0.01), while CD62p reexpression decreased gradually (p < 0.01). There were no significant differences in HSR level of platelets during storage (p > 0.05). R value increased with prolongation of preserved time (p < 0.01). There were no obvious changes on K value and alpha Angle during storage (p > 0.05). There were no obvious changes in MA from 1 to 4 days, and MA decreased slightly on day 5 (p < 0.05). It is concluded that there was no significant change in MA and HSR which reflects comprehensive coagulation of platelets during storage. Platelets on the end of storage have excellent function of hemostasis; Thrombelastography parameter MA value can be used as a valuable indicator for evaluation of platelet function in vitro during storage.

Slide platelet aggregation test used as a monitor for patient treated with anti-pletelet drugs / 中国实验血液学杂志

The aim was to verify the effectiveness of slide platelet aggregation test (SPAT) to monitor the inhibition effect of anti-platelet drugs. A group of eight healthy volunteers was examined for SPAT value and T(50) (time necessary for reaching 50% of total aggregation) induced by ADP, arachidonic acid (AA) and cationic propyl gallate (c-PG) respectively before and after administration of ASA in dose of 100 mg/day for 3 days. The group of 41 inpatients at the Department of Cardiovascular Disease treated with anti-platelet drugs and the group of 327 healthy blood donors were also examined for SPAT. The SPAT value of healthy volunteer samples stored at room temperature were measured hourly for four hours. The results showed that: (1) no significant difference was detected between the T(50) before and after ASA administration in health volunteer group when ADP was used as inducer, but a significant difference was detected in this group when AA or c-PG was used as inducer. There was significant linear correlation between SPAT value and T(50) induced by c-PG in health volunteer group before and after administration of ASA (r = 0.998, P = 0.000); (2) there was no significant difference between the SPAT value of health volunteer group before administration of ASA and the SPAT value of health blood donors group (P = 0.853), but there was a significant difference between the SPAT values before and after administration of ASA in health volunteer group (P = 0.000). There was significant difference when the SPAT value of the inpatients treated with anti-platelet drugs was compared with that of healthy blood donor group and with that of health volunteer group before and after administration of ASA (P = 0.000). The cut-off value of SPAT in health blood donor group was 44.6 +/- 11.7 seconds, reference value was from 21.1 seconds to 68.0 seconds; (3) there was no significant difference between SPAT values when platelets samples stored at room temperature for 1, 2, 3, 4 hours (P = 0.815). In conclusion, SPAT can rapidly monitor the inhibition effect of anti-platelet drugs and SPAT may have the similar clinic value with T(50) induced by c-PG.

Comparison of platelet activators used in slide platelet aggregation test / 中国实验血液学杂志

The study was purposed to explore the suitable platelet activators to be used in slide platelet aggregation test. Experiments were as follows: (1) to detect the intensity and time in 15 healthy donors' platelet aggregation tests induced by cationic propyl gallate (c-PG) and the usual platelet activators: ADP, collagen, epinephrine, arachidonic acid and ristocentin, respectively; (2) to detect the time in platelet aggregation tests of 15 healthy donors induced by c-PG and the above usual platelet activators respectively after addition of PGI2, cAMP or EDTA; (3) to detect the time in 15 healthy donors' platelet aggregation tests induced by c-PG after addition of heparin; (4) to detect the intensity and time of platelet aggregation induced by c-PG at the platelet count of (240-15) x 10(9)/L, (5) to detect the time of platelet aggregation induced by c-PG in eight patients each of whom had taken 100 mg aspirin per day for five days. The results showed that (1) c-PG reduced the strongest intensity of platelet aggregation and the time taken was appropriate, (2) c-PG was the most effective activator to reveal the inhibitive effect on platelet by PGI2, cAMP or EDTA, (3) 0.5 - 3 U/ml heparin did not significantly change the platelet aggregation induced by c-PG, (4) 15 healthy donors' platelet aggregation induced by c-PG displayed clearly on the slide until the platelet count below 30 x 10(9)/L, (5) The platelet aggregation time induced by c-PG was significantly prolonged in eight patients who had taken aspirin. In conclusion, compared to the usual platelet activators, c-PG has remarkable potential advantages when used in slide platelet aggregation test.

Effects of leukocyte elimination before storage on quality of red blood cell concentration / 中国实验血液学杂志

The objective of this study was to explore the possible effects of leukocyte elimination by filteration before storage on the quality of red blood cell concentrations (RCC) that prepared through two procedures. Eight units of red blood cell concentrations derived from whole blood after plasma separated (RCC1) and eight units of red blood cell concentrations derived from whole blood after platelet-rich plasma separated (RCC2) were divided randomly into filtered group and control group respectively. The RCC of filtered group were filtered by leukocyte deplete filter before storage. The control group didn't have any other treatments. These two groups were stored for five weeks at 4 degrees C according to AABB standard. Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and plasma concentration of K(+) and lactate dehydrogenase (LDH), free hemoglobin (FHb), adenosine triphosphate (ATP) of red blood cell of all RCC were evaluated weekly, and bacteria contamination of all RCC was also detected after five weeks of storage. The results showed that there was no difference of MCV, MCH and MCHC and ATP level of red blood cell in all RCC of two groups, the ATP of red blood cell was lower than the control group on week 4 and 5. The average concentration of K(+) of the filtered group was less than the control group. The differences are significant except that of RCC1 stored till the third week. The plasma LDH concentration of filtered group was less than the control group, and the differences were exacerbate during the storing time prolonged. FHb release in the filtered group of RCC2 was significant less than that of control, but no significant difference was found between the two groups of RCC1. It was concluded that leukocyte elimination by filter before storage could be benefit to RCC preservation.

Optimization of Saccharomyces cerevisiae sp.Strain by1.1b Culture Conditions for Efficient Biosynthesis of D-(-)-mandelate Dehydrogenase / 微生物学通报

The culture conditions of Saccharomyces cerevisiae sp.strain by 1.1 b were optimized for the production of D-(-)-mandelate dehydrogenase which is useful for the asymmetric bioreduction of benzoylformate to form D-(-)-mandelate.The optimum medium(per liter)consistes of 60 g peptone,30 g maltose, 0.5 g MgSO_4,0.01 g ZnSO_4,1.0 g KCl.After optimization of the culture medium,the enzyme production in shake flasks is enhanced from 2.56 to 20.21 U/L.The optimum fermentation conditions were determined as follows:medium volume 100 mL(i.e.,40%for a 250-mL shake flask),pH 6.5,inoculum size 10%,temperature 30℃,and cultivation time 25 h.