Apoptosis ; Blood Platelets ; cytology ; Humans

In the present study, the performance of a new blood cell separator (COBE Spectra LRS Turbo Version 7.0) and that of the previous version LRS version 5.1 in the collection efficiency (CE), collection rate and residual white blood cells during platelet collection from donors were compared. 232 units of platelet concentrates (n = 232) were evaluated and 163 units were collected with the Spectra LRS version 5.1 (Group A) and 69 units with the LRS turbo version 7.0 (Group B). Donor's blood cell counts and parameters, platelet yield, collection efficiency and residual leukocytes in platelet concentrates were analysed. Results showed that the platelet yield was higher in group B than that in group A: (2.90 +/- 1.1) x 10(11) versus (2.58 +/- 1.2) x 10(11), P < 0.001; residual WBCs were less than 5 x 10(6) in 99.4% of group A platelet concentrates and in 97.1% of group B platelet concentrates. Collection efficiency was higher in group B than in group A: 51.4 +/- 8.7 versus 43.6 +/- 6.3. A correlation between platelet count before collecting blood and platelet yield was observed in both groups. In conclusion, the Spectra LRS Turbo version 7.0 showed a higher platelet yield than that with LRS version 5.1. Higher platelet counts before collection allow a higher platelet yield.
Blood Platelets ; cytology ; Cell Separation ; instrumentation ; methods ; Humans ; Leukocyte Count ; Leukocytes ; cytology ; Platelet Count

This study was aimed to investigate the stability and in vitro function of glycosylated platelets concentrates after long-term refrigeration. The experiments were divided into 4 groups: group preserved at room temperature (RT group), group preserved at 4 degrees C (4T group), group glycosylated and preserved at 4 degrees C (U + 4 group) and group preserved at 4 degrees C and glycosylated (4 + U group). All groups followed for up to 14 days. The binding rate of RCA I lectin and expression of Plt surface markers CD62P, CD42b and Annexin V binding were determined by flow cytometry. pH and mean volume were determined by pH meter and hematotocytometer respectively. Platelet aggregation was detected by aggregometer. The results showed that during storage up to 14 days RCAI binding rate of modified groups was 5 - 6 fold of RT group. The pH of platelets suspension had no significant difference between these two groups (p > 0.05). Mean volumes of both groups (10.6 +/- 1.9 fL and 11.14 +/- 1.1 fL) were also no significant difference (p > 0.05). Furthermore, aggregation responsiveness of modified groups was better than that of RT groups (p < 0.05) although both decreased during the storage. The expression level of CD62P, CD42b and Annexin V binding during 5 days of storage had no significant difference between modified and fresh platelet groups (p > 0.05). While the expression level of CD62P and PS increased and the expression level of CD42b decreased during storage up to 14 days, there was significant difference between modified and fresh platelet groups (p < 0.01). It is concluded that the glycan modification is stable during storage up to 14 days. The glycosylated platelets retain in vitro function better than RT platelets during storage, but it shows activation to varying degrees in vitro after storage for 5 days.
Blood Platelets ; cytology ; metabolism ; Blood Preservation ; Cryopreservation ; methods ; Galactose ; pharmacology ; Glycosylation ; Humans ; Platelet Aggregation ; drug effects

This study was aimed to investigate the aggregation of rehydrated-lyophilized platelets. The aggregation rate of fresh and rehydrated-lyophilized platelets were measured by using thrombin, ristocetin, ADP and collagen as inductors and APACT2 aggregameter; the effects of intra- and extra-cellular trehalose on maximum aggregation rate of rehydrated-lyophilized platelets were detected by using ADP as an inductor. The results showed that the aggregation rate of fresh platelets was all about 100%, while aggregation rate of rehydrated lyophilized platelets was (70.17 +/- 7.36)%, (15.3 +/- 2.81)%, (68.67 +/- 6.86)%, (64.67 +/- 11.6)% respectively, when the concentration of thrombin, ristocetin, ADP and collagen was 1 U/ml, 1.6 mg/ml, 20 micromol/L and 2 microg/ml. The maximum aggregation rates of rehydrated-lyophilized platelets in intra- and extra-cellular trehalose, extracellular trehalose and blank control groups were (66.0 +/- 4.69)%, (25.3 +/- 2.42)% and (11.5 +/- 1.87)% (P < 0.01), meanwhile there was significant difference of rehydrated-lyophilized platelet aggregation rate between intra- and extra-cellular trehalose and extracellular trehalose groups (P < 0.01). It is concluded that the concentrations of thrombin (1 U/ml), ristocetin (1.6 mg/ml), ADP (20 micromol/L) and collagen (2 microg/ml) are optimal for platelets aggregation tests, the internal and extracellular trehalose significantly enhance the aggregation of rehydrated-lyophilized platelets.
Blood Platelets ; cytology ; drug effects ; metabolism ; Blood Preservation ; methods ; Freeze Drying ; methods ; Humans ; Platelet Aggregation ; physiology

OBJECTIVETo investigate the relationship between acute graft rejection early after renal transplantation and the variations of platelet parameters.

METHODSWe retrospectively analyzed the clinical data of 167 renal transplant recipients before and within 2 months after the surgery. Before and at 1-10 days, 15 days, 30 days, 45 days and 60 days after the transplantation, 5 platelet parameters, including platelet count (PLT), platelet hematocrit (PCT), mean platelet volume (MPV), platelet volume distribution width (PDW), and large platelet ratio (P-LCR), were detected in the 35 patients with acute graft rejection within two months (AR group) and in the other 132 recipients with good graft recovery (control group).

RESULTSThe AR group and control group showed no significant difference in PLT, PCT, MPV, or P-LCR before the surgery, but the PDW was significantly higher in the AR group (t=2.18, P=0.035). These parameters were similar within 5 postoperative days between the two groups (P>0.05), but in postoperative days 6-15, the AR group showed significantly increased MPV, PDW and P-LCR compared with the control group (P<0.05). In postoperative days 6-9, MPV, PDW and P-LCR became stable in AR group but tended to decrease in the control group, showing obviously different patterns of variation between the two groups (P<0.05).

CONCLUSIONSPreoperative PDW may have a positive correlation with acute graft rejection after renal transplantation. Monitoring the variations of MPV, PDW and P-LCR may help in the diagnosis of acute graft rejection early after renal transplantation.

OBJECTIVE: To induce hematopoietic progenitor/stem cells of umbilical cord blood to differentiate into mature megakaryocytes and platelets in vitro and to investigate the mechanism of production of platelets. METHODS: The CD34+ cells were sorted from umbilical cord blood by magnetic activated cell sorting (MACS) and then cultured in vitro with optimized medium to be differentiated into mature megakaryocytes and platelets. The cultured cells and the platelet-like particles were isolated from the culture and were checked by the fluorescence-activated cell sorter (FACS), immunohistochemistry assays, light microscope,electron microscope and platelet aggregation tests. RESULTS: The cultured megakaryocytes were detected with proplatelets and both the cultured cells and the platelet-sized particles were found to have the same structure with the normal megakaryocytes and platelets by light and electron microscope. The immunohistochemistry assays revealed the cultured cells expressed GP II b III a with a positivity of 95% which was a special antigen for platelets and megakaryocytes. Culture-derived platelet-sized particles aggregated in response to thrombin as the plasma derived-platelets did. The cultured platelets had the same positivity of CD41 as the platelets from platelet rich plasma. CONCLUSION The hematopoietic progenitor/stem cells can be induced to differentiate into purified and mature megakaryocytes and platelets. It provides a practical way to study the mechanism of platelets production.
Antigens, CD34 ; metabolism ; Blood Platelets ; cytology ; Cell Differentiation ; physiology ; Cells, Cultured ; Fetal Blood ; cytology ; metabolism ; Hematopoietic Stem Cells ; cytology ; metabolism ; Humans ; Megakaryocytes ; cytology

OBJECTIVETo explore a new method for in vitro expansion of human mesenchymal stem cells (MSC) by using platelet-rich plasma (PRP) in place of fetal calf serum (FCS).

METHODSBone marrow(BM) samples were obtained from the proximal femurs of patients with normal haematopoietic function undergoing total hip arthroplasty. 2 x 10(5)/cm2 BM nucleated cells were seeded in 25 cm2 flasks for MSC cultivation containing one of the 3 mediums: complete Dexter medium with 12.5% FBS and 12.5% horse serum (medium1), alpha-MEM with 10% FCS (medium2) and alpha-MEM with 5% PRP(medium3). At the same time, 1 x 10(6) nucleated BM cells and same amount of nucleated cells from iliac aspirate were seeded in 25 cm2 tissue flasks, colony forming unit-fibroblast (CFU-F) assay.

RESULTSCulture-expanded cells from proximal femurs presented a typical fibroblast-like morphology. Cells were positive for SH2 (CD 105), SH3 (CD73), Thy-1 (CD90), while negative for CD34 and CD45. On induction, these cells could differentiate into osteoblasts. A significantly higher proliferative capacity of MSCs expanded in medium3 was observed in comparison to those in mediuml or 2 without alteration of the phenotype and the differentiation property. CFU-F assays indicated that bone marrow from the proximal femoral contained significantly more CFU-F than that from iliac aspirate.

CONCLUSIONPlatelet-rich plasma can be used in place of FCS to provide a safer and more effective culture condition to expand MSCs for clinical purpose. The proximal femur BM cells can be obtained in hip surgeries.

Platelet-enriched plasma (PRP) contains high concentration of platelets and abundant growth factors, which is made by centrifuging of blood and separating of blood elements. PRP promotes tendon repair by releasing various cytokines to enhance cell proliferation, tenogenic differentiation, formation and secretion of matrix; meantime, it can reduce pain by inhibiting the expression of pain-associated molecules. A number of clinical studies demonstrated that PRP was effective in treatment of tendinopathy, including patellar tendinopathy, lateral epicondylitis and plantar fasciopathy. However, some studies did not support this conclusion, because of disparity of PRP types, therapeutic courses and injections protocols in clinical application. Based on its safety, PRP can be a choice of treatment for tendinopathy, in case other non-surgical therapies are of no effect.
Blood Platelets ; cytology ; Cytokines ; metabolism ; Humans ; Intercellular Signaling Peptides and Proteins ; metabolism ; Platelet-Rich Plasma ; Tendinopathy ; therapy

The dielectric spectroscopy of human platelets was measured within the frequency range of 100 KHz-100 MHz, and the dielectric numerical characters of human platelets in response to AC electric field were analyzed. We measured the AC impedance of normal human platelets with the impedance technique in the frequency domain for the first time. The experimental data were used to draw a relationship curve between the frequency of electric field and permittivity or conductivity, and then the dielectric spectrum and the Cole-Cole plots of human platelets were established and then, the characteristics of dielectric response of human platelets were decided, which demonstrated the dependence of permittivity and conductivity of human platelets upon frequency, and showed two characteristic frequencies of the dielectric spectroscopy of human platelets: the first characteristic frequency f(C1) = 6.66 MHz; the second characteristic frequency f(C2) = 9.81 MHz.
Blood Platelets ; cytology ; physiology ; Electric Conductivity ; Electric Impedance ; Electrochemistry ; methods ; Electrophysiology ; Humans ; Spectrum Analysis ; methods

The nervous system directly regulates immunity through neurotransmitter receptors expressed on immune cells to participate in host defense and body reparation. Expression of neurotransmitter receptors on blood cells provides important evidence for a direct functional link between the nervous and hematopoietic systems. Our previous studies showed that 5-hydroxytryptamine, as a monoamine neurotransmitter, plays an important role in regulating megakaryocytopoiesis. This review summarizes recent findings of the effect of monoamine neurotransmitter on megakaryocytopoiesis and platelet function, focusing on the receptor expression on hematopoietic stem cells, megakaryocytes/platelets and their functions in order to explore the intrinsic relation of nervous system and hematopoietic system. Based on the existing research results, we find that the monoamine neurotransmitter participates in regulation of megakaryocytopoiesis, and affects on aggregation and functions activation of platelets. Moreover, it has a close link with the specific regulatory factor of megakaryocytopoiesis-TPO. Thus those results also support the "brain-bone marrow-blood-axis" viewpoint of some researchers. At present, the study of the nervous system regulating hematopoiesis is still in its infancy, the exact mechanism remains to be further studied.
Biogenic Monoamines ; physiology ; Blood Platelets ; physiology ; Humans ; Megakaryocytes ; cytology ; Neurotransmitter Agents ; physiology ; Platelet Function Tests