Wound biotherapy, represented by platelet concentrate derivatives, has attracted much attention. However, there are some different viewpoints due to the disunity of quality control of preparation, the ways of use, and so on. The members of the consensus writing group reviewed a large number of literatures, screened out high-quality evidence references, combined with the repeated discussion of experts in the field of wound repair to form a guiding consensus of experts, so as to guide medical personnel using enriched platelet treatment scientifically and standardly in wound repair.
Blood Platelets/physiology* ; Consensus ; Humans ; Wound Healing/physiology*

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 ).
Blood Platelets ; physiology ; Blood Preservation ; Cryopreservation ; Crystallization ; Humans ; Temperature

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

Angiogenesis is a process involving the growth of new blood vessels from pre-existing vessels though sprouting or other ways. It plays an important role in both physiological and pathological processes. Researches have found that platelets may contribute to angiogenesis as well. In this paper, we review the role of platelet in angiogenesis, especially the relationship with tumor angiogenesis, and discuss clinical implications of these findings.
Blood Platelets ; physiology ; Humans ; Neoplasms ; blood supply ; Neovascularization, Pathologic ; physiopathology ; Neovascularization, Physiologic ; physiology ; Vascular Endothelial Growth Factor A ; physiology

Platelets play a key role in the pathogenesis of atherothrombosis, and also perform the physiological hemostasis. The platelet function assays have values in the investigating patients with suspected platelet disorders and in studying the effects of anti-platelet drugs. There are increasing assays for investigating platelet function, including assessment of platelet adhesion, activation and aggregation, etc. However, all of these assays have certain limited sensitivity. It is necessary to develop a simple, sensitive assay that measures the activated platelet. This article reviewed advances of researches on platelet function assays, including assay for general function of platelet, assay of platelet adhesion function, platelet activation assay, platelet aggregation assay, platelet coagulation assay and application of flow cytometry in assessment of platelet functions, etc. and looked forward to research prospect in this field.
Blood Platelets ; physiology ; Humans ; Platelet Activation ; physiology ; Platelet Adhesiveness ; physiology ; Platelet Aggregation ; physiology ; Platelet Function Tests ; methods ; trends

OBJECTIVETo review and summarize literature regarding stimulatory and inhibitory signaling pathways from different types of Fc gamma receptors (FcgammaRs).

DATA SOURCEArticles were obtained from Medline from January 1991 to April 2002.

STUDY SELECTIONOver 100 English language papers and reviews published over the last 11 years were selected.

RESULTS AND CONCLUSIONSStimulatory Fcgamma receptors include FcgammaRI, FcgammaRIIA, FcgammaRIIC, and FcgammaRIII A. They transduce signals through the immunoreceptor tyrosine-based activation motif (ITAM) in subunits or in the cytoplasmic domain. Inhibitory Fcgamma receptors, such as FcgammaRIIB, are single chain receptors, transducing signals through an immunoreceptor tyrosine-based inhibitory motif (ITIM) in cytoplasmic domains. Stimulatory signals include protein phosphorylation, increase in intracellular free calcium, the production of 1,4,5-triphosphate inositol (IP(3)) and diacylglycerol (DAG) mainly through the Src-family kinases, phosphoinositide 3-kinase (PI3-K) and phospholipase C (PLC). Inhibitory signaling has been implicated in the repression of the above activities as well as inhibition of B cell responses through Src homology 2-containing inositol phosphatase (SHIP).

Amino Acid Motifs ; Animals ; Blood Platelets ; physiology ; Humans ; Phagocytes ; physiology ; Receptors, IgG ; chemistry ; physiology ; Signal Transduction ; physiology

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

Lyophilization is the best preservation of platelets at present. Lyophilized platelets could be stored in circumstance temperature, small space and be transported with portability, but lyophilizing may damage platelet membrane, denature protein and induce platelet activation. The chain of events including freezing and drying that lead to activation are related to the phase transition of platelet membrane lipid. Application of protectants in accordance with damage mechanism of lyophilization could alleviate the damnification. Human platelets can be preserved using lyophilization successfully in the presence of trehalose in laboratory presently, that retains normal functions and activities after rehydration. These findings suggest that the application of lyophilized platelets in transfusion medicine will be carried out in future. In this paper damage effect of lyophilization on platelets, application of cryoprotectants in the platelet lyophilization and experimental studies on platelet cryopreservation were reviewed.
Blood Platelets ; physiology ; Blood Preservation ; Cryoprotective Agents ; pharmacology ; Freeze Drying ; Humans

The purpose of this study was to establish a set of techniques for cryopreservation of platelets with dimethylsulphoxide (DMSO) to insure high quality of cryopreserved platelet. The methods were as following: (1) DMSO was filtered in stead of being sterilized before infusion into the bag with platelets. (2) The whole blood was centrifuged immediately after blood collection and the attached tube was tied on the top of the bucket. (3) The related centrifugal force was 480 x g, the accelerating and braking grades of the centrifuge for acceleration and deceleration were 9 and 4 respectively. (4) The flow rate of platelet rich plasma (PRP) could not be too high, 80 - 100 ml PRP should be harvested at 1 minute or so. The infusion rate of DMSO into the PRP was 1 ml/min. After the infusion of DMSO, the PRP bag must be put into the -80 degrees C ultra low freezer at once to make the product to be freezed as soon as possible. The cryopreserved platelet should be thawed in the cycling warm water at the temperature of 38 - 40 degrees C. (5) After thawing of platelet, the platelet, red blood cell and white blood cell were counted, and the bacteria culturing, tests for HBsAg, anti-HCV, anti-HIV, TP and ALT were carried out. The results showed that altogether 14 800 units of cryopreserved platelets were prepared including 80 units collected with blood cell separator, of which quality control was accomplished in 300 units. The manually collected platelet mean count >/= 2.4 x 10(10)/unit, while the apheresis platelet count >/= 2.5 x 10(11)/unit. The yield was over 70%. The contaminated red and white blood cells were platelets showed obvious effect of haemostasis. In conclusion, the cryopreserved platelets prepared with this method were of high quality and efficaciousness in haemostasis clinically.
Blood Platelets ; physiology ; Blood Preservation ; Cryopreservation ; Dimethyl Sulfoxide ; pharmacology ; Humans ; Platelet Transfusion ; Quality Control

The glycosylation of platelets may prolong their life-span when being transfused after preservation under 4 degrees C, therefore this study was aimed to investigate the effect of glycosylation on morphology, ultrastructure, function and membrane glycoprotein of platelets. The experiments were divided into 3 groups: group preserved in room temperature (RT group), group preserved in 4 degrees C (4T group) and group UDP-Gal glycosylated and preserved in 4 degrees C (U+4T group). The binding rate of RCA I lectin and expression of platelet surface markers CD62P, CD42b were determined by flow cytometry. Morphology and ultrastructure of platelets were observed by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Platelets aggregation was detected by aggregometer. The results showed that the binding rate of RCAI in U+4T group significantly higher than that in RT group (p<0.01), no obvious changes was found in ultrastructure of glycosylated platelets, as compared with fresh platelets. Some morphologic changes, such as pseudopodium could be observed in 4T group. The aggregation rate of platelets in U+4T group reached to 50% of RT group. The expression levels of CD42b and CD62P, and the binding rate of annexin V in U+4T group were not significantly different from that in RT group. It is concluded that UDP-Gal can effectively cause galactosylation of platelets, and the platelets modified with UDP-Gal remain normal morphology, ultrastructure and function.
Blood Platelets ; drug effects ; physiology ; ultrastructure ; Blood Preservation ; methods ; Cryopreservation ; methods ; Galactose ; pharmacology ; Glycosylation ; Humans