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Blood Components (blood + component)
Selected AbstractsDistribution and dynamic changes of sphingolipids in blood in response to platelet activationJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2006F. DAHM Summary.,Background:,Sphingolipids are signaling molecules in a range of biological processes. While sphingosine-1-phosphate (S1P) is thought to be abundantly stored in platelets and released upon stimulation, knowledge about the distribution and function of other sphingolipids in blood is lacking. Objectives:,To analyze the sphingolipid content of blood components with special emphasis on dynamic changes in platelets. Methods:,Blood components from mice and humans were prepared by gradient centrifugation and analyzed by liquid chromatography,mass spectrometry. Additionally, murine platelets were activated in vitro and in vivo. Results:,Isolated non-activated platelets of mice were devoid of S1P, but instead contained dihydrosphingosine-1-phosphate (dhS1P), along with a high concentration of ceramide. Activation of platelets in vitro led to a loss of dhS1P and an increase in sphingosine, accompanied by a reduction of ceramide content. Platelet activation in vivo led to an immediate and continuous rise of dhS1P in plasma, while S1P remained stable. The sphingolipid distribution of human blood was markedly different from mice. Human platelets contained dhS1P in addition to S1P. Conclusions:,Mouse platelets contain dhS1P instead of S1P. Platelet activation causes loss of dhS1P and breakdown of ceramide, implying ceramidase activation. Release of dhS1P from activated platelets might be a novel signaling pathway. Finally, the sphingolipid composition of mouse and human blood shows large differences, which must be considered when studying sphingolipid biology. [source] Good practice in plasma collection and fractionationISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010C. Schärer The control strategy to ensure safety of blood products includes a combination of measures focusing on ensuring the quality and safety of starting material by careful donor selection and testing strategies at different levels, together with validated manufacturing processes, including steps to inactivate or remove potential contaminating agents. Using an approach based on good manufacturing practice (GMP) provides a manufacturing model that allows for a documented system of incorporating quality throughout the entire manufacturing process and describes the activities and controls needed to consistently produce products that comply with specifications and are safe for use. There are no doubts that the aim of providing safe and high-quality product to the patients should be the same for all products derived from human blood, independent of its use either as a blood component for direct transfusion or as industrially manufactured product. It would be difficult to justify whether for blood components the good practice standards and for plasma derivatives the GMP standards for manufacturing would not ensure equivalent levels of quality and safety. To ensure a high level of quality and safety of blood components and plasma derivatives, the implementation of double standards in blood establishments and fractionation industry would not be effective and should be avoided. Harmonized standards and good practices for collection and fractionation, based on the principles of GMP, should be envisaged in the whole chain of manufacturing blood components and plasma derivatives. Global initiatives to further promote the implementation of harmonized GMP for the collection in blood establishments and a stringent regulatory control are ongoing. This would further contribute to the global availability of plasma-derived medicinal products. [source] Anti-thrombogenicity of styrene-butadiene-styrene triblock copolymer grafted with poly(ethylene glycol)sJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009Masanobu Nagura Abstract We transformed hydrophobic/hydrophobic styrene/butadiene/styrene tri-block copolymer (SBS) to hydrophobic / hydrophilic microphase-separated surfaces by grafting with hydrophilic poly(ethylene glycol) (PEG) on poly(butadiene) (PB) domain via hydrocarboxylation and hydrobromination and investigated the anti-thrombogenicity of these surfaces. In the case of SBS cast film from toluene solution, PEG was densely grafted because of the development of an unevenness on the order of several 10 nm on the surface, which had a huge surface area in comparison with poly(butadiene) rubber with its uniformly smooth surface. Grafted PEG (molecular weight = 600) was found to clearly inhibit adhesion and activation of platelets and coagulation of the whole blood component, which is indicative of anti-thrombogenicity. These properties correspond to a surface coated by a copolymer of 2-methacryloyl-oxyethyl phosphorylcholine and n -butyl methacrylate, which is well known to be the best excellent anti-thrombogenic material in the world. Melt-molded SBS film, which also has an uneveness on the order of several 10 nm, showed similar excellent anti-thrombogenicity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Development of a liquid chromatographic time-of-flight mass spectrometric method for the determination of unlabelled and deuterium-labelled , -tocopherol in blood componentsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2003Wendy L. Hall A method is described for the analysis of deuterated and undeuterated , -tocopherol in blood components using liquid chromatography coupled to an orthogonal acceleration time-of-flight (TOF) mass spectrometer. Optimal ionisation conditions for undeuterated (d0) and tri- and hexadeuterated (d3 or d6) , -tocopherol standards were found with negative ion mode electrospray ionisation. Each species produced an isotopically resolved single ion of exact mass. Calibration curves of pure standards were linear in the range tested (0,1.5,,M, 0,15,pmol injected). For quantification of d0 and d6 in blood components following a standard solvent extraction, a stable-isotope-labelled internal standard (d3- , -tocopherol) was employed. To counter matrix ion suppression effects, standard response curves were generated following identical solvent extraction procedures to those of the samples. Within-day and between-day precision were determined for quantification of d0- and d6-labelled , -tocopherol in each blood component and both averaged 3,10%. Accuracy was assessed by comparison with a standard high-performance liquid chromatography (HPLC) method, achieving good correlation (r2,=,0.94), and by spiking with known concentrations of , -tocopherol (98% accuracy). Limits of detection and quantification were determined to be 5 and 50,fmol injected, respectively. The assay was used to measure the appearance and disappearance of deuterium-labelled , -tocopherol in human blood components following deuterium-labelled (d6) RRR - , -tocopheryl acetate ingestion. The new LC/TOFMS method was found to be sensitive, required small sample volumes, was reproducible and robust, and was capable of high throughput when large numbers of samples were generated. Copyright © 2003 John Wiley & Sons, Ltd. [source] Established ways to keep donor's interest aliveISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010J. Ringwald Background, The future demographic changes will be associated with an enhancement of the worldwide shortage of blood. The ageing of the population in developed countries is associated with a decrease in young individuals being potentially eligible to donate blood and an increase in older individuals who might be in the need of blood transfusion. Therefore, the retention of active blood donors (BD) is becoming more important. A substantial increase in blood donations could be achieved by a relatively small increase in BD return. It is the task of blood donation services (BDSs) to elaborate specific and adequate measures to increase the BD's likelihood to return. Successful BD retention programmes are viable to ensure a sufficient supply with blood and blood components at present and the upcoming years. Aims, To give recommendations for BD retention strategies based on a survey of potential and established measures how BD's interest could be kept alive. Methods, With focus on the last decade, literature about internal and external influences on BD's intention to regular blood donation and their actual return behaviour was reviewed. Furthermore, a special aspect was drawn on published articles about established or potential measures to increase BD's return-rate. Based on this information, different ways how BD's interest could be kept alive were suggested. Results, Overall, individuals of younger age (< 30,40 years), women, those with a lower education level are less likely to return to blood donation. External influences of friends, family or co-workers are import for starting a BD career. To become a committed BD, however, a high level of intrinsic motivation is needed. To keep BD's interest alive for a long time, BDSs should focus on the following to increase the satisfaction of the BD: Make blood donation a good experience and as convenient as possible, reduce adverse events and anxiety, and train and motivate your staff. This could be further supported by an intensive and active communication with the BDs right from the start, the application of loyalty builders to establish BD identity, and the appropriate use of incentives. Finally, temporarily deferred BDs should ask to return personally and advertisement programmes for repeat BDs should appeal on personal motivation and moral norms. However, BDS should always try to adapt their measures on their target population considering that people are different all around the world. Moreover, some promotion programmes should be even tailored for distinct subgroups of BDs to have a successful outcome. Conclusions, There is quite a number of ways to keep BDs interest alive and to start a career as a regular and committed BD. In this context, the self-identification as a BD is definitely of major importance. BDSs are challenged to support this developmental process. They have to make sure that blood donation is associated with a good experience for the BD, making him or her feeling good and happy. [source] Good practice in plasma collection and fractionationISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010C. Schärer The control strategy to ensure safety of blood products includes a combination of measures focusing on ensuring the quality and safety of starting material by careful donor selection and testing strategies at different levels, together with validated manufacturing processes, including steps to inactivate or remove potential contaminating agents. Using an approach based on good manufacturing practice (GMP) provides a manufacturing model that allows for a documented system of incorporating quality throughout the entire manufacturing process and describes the activities and controls needed to consistently produce products that comply with specifications and are safe for use. There are no doubts that the aim of providing safe and high-quality product to the patients should be the same for all products derived from human blood, independent of its use either as a blood component for direct transfusion or as industrially manufactured product. It would be difficult to justify whether for blood components the good practice standards and for plasma derivatives the GMP standards for manufacturing would not ensure equivalent levels of quality and safety. To ensure a high level of quality and safety of blood components and plasma derivatives, the implementation of double standards in blood establishments and fractionation industry would not be effective and should be avoided. Harmonized standards and good practices for collection and fractionation, based on the principles of GMP, should be envisaged in the whole chain of manufacturing blood components and plasma derivatives. Global initiatives to further promote the implementation of harmonized GMP for the collection in blood establishments and a stringent regulatory control are ongoing. This would further contribute to the global availability of plasma-derived medicinal products. [source] Comparison of different methods of bacterial detection in blood componentsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2009M. Schmidt Background, Over the last two decades, the residual risk of acquiring a transfusion-transmitted viral infection has been reduced to less than 1 : 1 000 000 via improvements in different techniques (e.g. donor selection, leuco-depletion, introduction of 3rd or 4th generation enzyme-linked immunosorbent assays and mini-pool nucleic acid testing (MP-NAT). In contrast, the risk for transfusion-associated bacterial infections has remained fairly stable, and is estimated to be in a range between 1 : 2000 and 1 : 3000. Platelets are at an especially higher risk for bacterial contamination, because they are stored at room temperature, which provides good culture conditions for a broad range of bacterial strains. To improve bacterial safety of blood products, different detection systems have been developed that can be divided into culture systems like BacT/ALERT or Pall eBDS, rapid detection systems like NAT systems, immunoassays and systems based on the FACS technique. Culture systems are used for routine bacterial screening of platelets in many countries, whereas rapid detection systems so far are mainly used in experimental spiking studies. Nevertheless, pathogen-reduction systems are currently available for platelet concentrates and plasma, and are under investigation for erythrocytes. Methods, In this review, the functional principles of the different assays are described and discussed with regard to their analytical sensitivity, analytical specificity, diagnostic sensitivity, diagnostic specificity and clinical efficiency. The detection methods were clustered into three groups: (i) detection systems currently used for routine screening of blood products, (ii) experimental detection systems ready to use for routine screening of blood products, and (iii) new experimental detection systems that need to be investigated in additional spiking studies and clinical trials. Results, A recent International Society of Blood Transfusion international forum reported on bacterial detection methods in 12 countries. Eight countries have implemented BacT/ALERT into blood donor screening, whereas in three countries only quality controls were done by culture methods. In one country, shelf-life was reduced to 3 days, so no bacterial screening was implemented. Screening data with culture methods can be used to investigate the prevalence of bacterial contamination in platelets. Differing results between the countries could be explained by different test definitions and different test strategies. Nevertheless, false-negative results causing severe transfusion-related septic reactions have been reported all over the world due to a residual risk of sample errors. Rapid screening systems NAT and FACS assays have improved over the last few years and are now ready to be implemented in routine screening. Non-specific amplification in NAT can be prevented by pre-treatment with Sau3AI, filtration of NAT reagents, or reduction of the number of polymerase chain reaction cycles. FACS systems offer easy fully automated handling and a handling time of only 5 min, which could be an option for re-testing day-5 platelets. New screening approaches like immunoassays, detection of bacterial adenosine triphosphate, or detection of esterase activity need to be investigated in additional studies. Conclusion, Bacterial screening of blood products, especially platelets, can be done with a broad range of technologies. The ideal system should be able to detect one colony-forming unit per blood bag without a delay in the release process. Currently, we are far away from such an ideal screening system. Nevertheless, pathogen-inactivation systems are available, but a system for all blood components will not be expected in the next few years. Therefore, existing culture systems should be complemented by rapid systems like NAT or FACS especially for day-5 platelets. [source] Pathogen-reduction methods: advantages and limitsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2009H. G. Klein Pathogen-reduction (inactivation) provides a proactive approach to reducing transfusion-transmitted infection. Pathogen-reduction technologies have been successfully implemented by plasma fractionators resulting in no transmission of human immunodeficiency, hepatitis C, or hepatitis B viruses by US-licensed plasma derivatives since 1987. Fractionation technologies cannot be used to treat cellular blood components. Although blood donor screening, deferral and disease testing have drastically reduced the incidence of transfusion-transmitted diseases, the threat of new or re-emerging pathogens remains. Of particular concern is the silent emergence of a new agent with a prolonged latent period in which asymptomatic infected carriers would donate and spread infection. The ultimate goal of pathogen-inactivation is to reduce transmission of potential pathogens without significantly compromising the therapeutic efficacy of the cellular and protein constituents of blood. The acceptable technology must not introduce toxicities into the blood supply nor result in neoantigen formation and subsequent antibody production. Several promising pathogen-inactivation technologies are being developed and tested, and others are currently in use, but all of them have limits. Pathogen-reduction promises an additional ,layer of protection' from infectious agents and has the potential to impact the safety of blood transfusions worldwide. [source] Where will pathogen inactivation have the greatest impact?ISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2007T. Hervig Blood safety has always been a major task in transfusion medicine. A strategy to obtain this aim should include donor education, donor selection, and testing of blood donations. Pathogen inactivation adds another level of safety. In the fractionation industry, pathogen inactivation methods are mandatory. Several countries also use pathogen-inactivated plasma , from pools or single donors. Concerning the cellular blood components, there is still no method available for red cell concentrates, whereas methods for platelet concentrates are available in some countries and others are in the pipeline for commercialization. The efficiency of the ,old' methods to increase blood safety and the costs of the methods seem to be major obstacles for the introduction of the systems. There are also concerns on product quality and loss of volume during the inactivation process. As the importance of pathogen inactivation is largest in countries with blood donors who carry infections it is impossible to protect against, either due to high incidence of the infection or due to shortage of tests, cost will be a major question when pathogen inactivation is considered. Pathogen inactivation of red cell concentrates will also be a necessity. When pathogen inactivation methods are available for all blood components, they will have great impact to protect the patients in countries where a high percentage of the population is infected by agents transmissible through blood transfusion, and in all situations to protect against new pathogens and ,old' pathogens that become more virulent. The total risk of contracting infectious diseases through blood transfusion will probably be important when implementation of new methods for pathogen inactivation is considered. [source] Influence of epidemiological factors on blood transfusionISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2007S. Laperche The prevalence, incidence and risk factors of infectious diseases observed in the general population have been described to directly influence transfusion medicine, especially the blood selection. The objective is to ensure the blood safety. The characterization of modes of transmission influences the donor selection: the risk factors of the main blood-borne infections have permitted to adapt the pre-donation questionnaire in order to exclude at-risk donors. The prevalence of infections also has an impact on the blood screening strategy. For example, anti-HBc antibody (Ab) screening is currently performed only in countries where the HBV prevalence is compatible with a reasonable number of donor exclusions. HTLV Ab screening is implemented in countries in which the rate of donors originating from endemic areas could represent a risk for blood components. Measurement of incidence which contributes to the residual risk has led to the introduction of nucleic acid testing (NAT) for HIV, HCV and in some cases for HBV in viral screening strategy in many countries worldwide. The observed NAT yield differs according to the incidence of the infection and according to the country. Finally, the putative blood transmission of new and emerging pathogens has led to implement specific and non-specific measures in order to enhance blood safety. Conversely, although the blood donor population is selected, the data observed in this population have also contributed to better understand epidemiology and pathogenesis of infection. Moreover, owing to the recent progress in developing modelling approaches for estimating risk, we are able to anticipate a transfusion transmission threat by introducing, when necessary, specific measures intended for reduce this risk. [source] European best practice in blood transfusion: improvement of quality-related processes in blood establishmentsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2007Christian Seidl Transfusion medicine is an expanding field comprising the interaction between several medical disciplines. Looking at the ,vein to vein process' covering the donation of blood by the voluntary donor up to the application of blood components to patients, modern blood transfusion services comprise a large variety of sociomedical functions. The production of standard cellular blood components, such as erythrocyte and thrombocyte concentrates, plasmatic blood components as well as special cellular components such as blood stem cells, mesenchymal cells or granulocytes will require an extensive laboratory testing repertoire to monitor product quality and safety. The European blood legislation has defined several key quality elements to achieve good manufacturing practice in the field of blood transfusion. In addition, GMP/GLP and ISO standards are used inter alia by blood establishments. Following the call for proposal in the field of public health by the European Commission, a consortium of blood establishments from 16 European member, acceding and EFTA states has been established in order to survey the individual quality management systems used by the participants and to developed guidelines for quality systems. These guidelines are aimed at assisting blood establishments in preparing for government inspections as required by Directive 2002/98/EC. They could also be used to adapt existing procedures to comply with current EU requirements and/or to prepare for accreditation and certification of these institutions. Major benefits from those quality management systems are (1) the definition of an overall quality policy, (2) improved personnel responsibility, qualification and training, (3) error and risk assessment system, (4) continuous improvement, (5) improved resource management, (6) performance improvement. The definition of cost,benefit relation between certification and accreditation of blood establishments will depend on the individual institution itself and the amount of processes covered. With the release of the new EU Directive 2005/62/EC, there are currently EU requirements available that describe in detail relevant processes to be covered by quality system following good practice used in blood establishments. A future challenge for transfusion medicine would be optimizing the synergetic effects expressed by the EU directive, GMP and ISO standards. [source] Novel method for clearing red blood cell debris from BacT/ALERT® blood culture medium for improved microscopic and antimycobacterial drug susceptibility test resultsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2007Krishnamoorthy Gopinath Abstract Even though automation in mycobacterial culture has immensely improved the detection of organisms, identification of species and antimycobacterial susceptibility testing from blood culture bottles remain cumbersome and error-prone due to the presence of intact red blood cells (RBCs). The removal or lysis of these RBCs and excessive protein from the blood components could theoretically help improve this process. The present study reports an effective method that uses ammonium chloride (NH4Cl) and Triton X-100 to lyse the RBCs in blood culture medium. The method was optimized by preparing various concentrations of NH4Cl and Triton X-100, and incubation conditions, leading to eight protocols. The lysis protocol with a concentration of 150,mM of NH4Cl, 0.5% Triton X-100, and 1% potassium bicarbonate, pH 7.0, and incubation at 37°C for 15,min was found to be optimal. This method not only made the culture medium clear, the protein concentration decreased from 753.5±39.4 to 53.2±4.2,mg/mL in the M. tuberculosis -spiked culture medium and in the blood culture medium inoculated with the blood from tuberculosis patients. The method had no adverse effect on mycobacteria, and no depletion of M. tuberculosis colony-forming units was found. The lysate could be used for antimycobacterial susceptibility testing with no difficulty in setting the mycobacterial concentration of inoculum to 0.5 McFarland standards. Furthermore, this method had the added advantage in the microscopy and molecular methods for the speciation of Mycobacterium sp. J. Clin. Lab. Anal. 21:220,226, 2007. © 2007 Wiley-Liss, Inc. [source] Pathogen inactivation technology: cleansing the blood supplyJOURNAL OF INTERNAL MEDICINE, Issue 3 2005H. G. KLEIN Abstract., Klein HG (The Johns Hopkins School of Medicine and Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD, USA). Pathogen inactivation technology: cleansing the blood supply (Review). J Intern Med 2005; 257: 224,237. The calculated residual infectious risk of HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) from blood transfusion is extremely low. However, the risk of bacterial contamination remains and a variety of other agents including emerging viruses, protozoa and tick-borne agents threaten blood supplies and undermine public confidence in blood safety. Traditional methods of donor screening and testing have limited ability to further reduce disease transmission and cannot prevent an emerging infectious agent from entering the blood supply. Pathogen inactivation technologies have all but eliminated the infectious risks of plasma-derived protein fractions, but as yet no technique has proved sufficiently safe and effective for traditional blood components. Half-way technologies can reduce the risk of pathogen transmission from fresh frozen plasma and cryoprecipitate. Traditional methods of mechanical removal such as washing and filtration have limited success in reducing the risk of cell-associated agents, but methods aimed at sterilizing blood have either proved toxic to the cells or to the recipients of blood components. Several promising methods that target pathogen nucleic acid have recently entered clinical testing. [source] Toxic effect of blood components on perinatal rat subventricular zone cells and oligodendrocyte precursor cell proliferation, differentiation and migration in cultureJOURNAL OF NEUROCHEMISTRY, Issue 5 2009Packiasamy A. R. Juliet Abstract The germinal matrix of human brain gives rise to oligodendrocytes and astrocytes after mid-gestation. Hemorrhage in the germinal matrix of premature infants is associated with suppressed cell proliferation. We hypothesize that soluble blood constituents have an adverse effect on the proliferation of cultured rat subventricular zone (SVZ) cells and the proliferation, migration, and differentiation of oligodendrocyte progenitor cells (OPC). Using caspase 3 activation and lactate dehydrogenase release assays, rat plasma, serum, thrombin, and kallikrein killed SVZ cells when grown in the presence (but not absence) of platelet derived growth factor. Plasma and serum killed OPC at 1 : 1 to 1 : 100 dilutions. Using a bromodeoxyuridine incorporation assay OPC proliferation was reduced by plasma, serum, thrombin and plasmin. Blood proteins also suppressed OPC migration in a concentration dependent manner. However, differentiation of OPC into myelin basic protein expressing cells was suppressed only by thrombin. We conclude that soluble blood components, particularly thrombin, have an adverse effect on maturing SVZ cells and OPC derived from newborn rat brain. [source] Effect of Er:YAG and Diode lasers on the adhesion of blood components and on the morphology of irradiated root surfacesJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2006Letķcia Helena Theodoro Objective:, The aim of this study was to evaluate in vitro, by scanning electron microscopy (SEM), the adhesion of blood components on root surfaces irradiated with Er:YAG (2.94 µm) and GaAlAs Diode (808 nm) lasers and the effects on the morphology of irradiated root surfaces. Methods:, One hundred samples of human teeth were obtained. They were previously planed and scaled with manual instruments and divided into five groups of 20 samples each: G1 (control group) , absence of treatment; G2 , Er:YAG laser (7.6 J/cm2); G3 , Er:YAG laser (12.9 J/cm2); G4 , Diode laser (90 J/cm2) and G5 , Diode laser (108 J/cm2). After these treatments, 10 samples of each group received a blood tissue but the remaining 10 did not. After laboratory treatments, the samples were obtained by SEM, the photomicrographs were analysed by the score of adhesion of blood components and the results were statistically analysed (Kruskall,Wallis and Mann,Whitney test). Results:, In relation to the adhesion of blood components, the study showed no significant differences between the control group and the groups treated with Er:YAG laser (p = 0.9633 and 0.6229). Diode laser radiation was less effective than control group and Er:YAG laser radiation (p < 0.01). Conclusions:, None of the proposed treatments increased the adhesion of blood components in a significant way when compared to the control group. Although the Er:YAG laser did not interfere in the adhesion of blood components, it caused more changes on the root surface, whereas the Diode laser inhibited the adhesion. [source] Distribution and dynamic changes of sphingolipids in blood in response to platelet activationJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2006F. DAHM Summary.,Background:,Sphingolipids are signaling molecules in a range of biological processes. While sphingosine-1-phosphate (S1P) is thought to be abundantly stored in platelets and released upon stimulation, knowledge about the distribution and function of other sphingolipids in blood is lacking. Objectives:,To analyze the sphingolipid content of blood components with special emphasis on dynamic changes in platelets. Methods:,Blood components from mice and humans were prepared by gradient centrifugation and analyzed by liquid chromatography,mass spectrometry. Additionally, murine platelets were activated in vitro and in vivo. Results:,Isolated non-activated platelets of mice were devoid of S1P, but instead contained dihydrosphingosine-1-phosphate (dhS1P), along with a high concentration of ceramide. Activation of platelets in vitro led to a loss of dhS1P and an increase in sphingosine, accompanied by a reduction of ceramide content. Platelet activation in vivo led to an immediate and continuous rise of dhS1P in plasma, while S1P remained stable. The sphingolipid distribution of human blood was markedly different from mice. Human platelets contained dhS1P in addition to S1P. Conclusions:,Mouse platelets contain dhS1P instead of S1P. Platelet activation causes loss of dhS1P and breakdown of ceramide, implying ceramidase activation. Release of dhS1P from activated platelets might be a novel signaling pathway. Finally, the sphingolipid composition of mouse and human blood shows large differences, which must be considered when studying sphingolipid biology. [source] Biological and Optical Properties of Fluorescent Nanoparticles Developed for Intravascular ImagingMICROSCOPY RESEARCH AND TECHNIQUE, Issue 9 2007Dino J. Ravnic Abstract Intravascular tracers in the blood circulation can provide a description of the flow field over time and space. To address the limitations of existing intravascular tracers, we have developed fluorescent nanoparticles capable of providing detailed information regarding the intravascular flow field. The nanoparticles were designed to maximize plasma half-life as well as minimize interactions with other blood components. The bioavailability of the particles in the blood circulation required nanoscale size and low surface charge density. Intravital imaging of nanoparticles in the microcirculation demonstrated that the fluorescence intensity of the nanoparticles was a major determinant of both temporal and spatial resolution of the flow field. We conclude that nanoparticles prepared with these physical and optical properties can provide an accurate description of the localized intravascular flow field. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source] Hematopoietic and immune recovery after allogeneic peripheral blood stem cell transplantation and bone marrow transplantation in a pediatric populationPEDIATRIC TRANSPLANTATION, Issue 4 2002Yoshihisa Nagatoshi Abstract: To compare the hematopoietic and immune recoveries after allogeneic transplantation with different cell sources, we analyzed the recovery patterns of blood components after allogeneic peripheral blood stem cell transplantation (PBSCT) in comparison with that after allogeneic bone marrow transplantation (BMT) in a pediatric population. Sixteen patients received PBSCT, and 24 received BMT between January, 1995 and March, 2000. The patients had acute lymphoblastic leukemia (ALL; n = 22), acute myelogenous leukemia (AML; n = 8), myelodysplastic syndrome (MDS; n = 3), or other diseases (n = 7). The median ages of patients in the PBSCT and BMT groups were 9 yr and 6 yr, respectively. Cyclosporin A (CsA) plus methotrexate or methylprednisolone was used as a graft-vs.-host disease (GvHD) prophylaxis regimen in the PBSCT group, whereas CsA alone or methotrexate alone was used in the BMT group. Circulating lymphocyte numbers and subpopulations determined by flow cytometric analysis were used as markers of immune recovery. In the PBSCT group, the median number of harvested CD34+ cells was 7.25 (range: 1.3,27.6) × 106/kg of the recipient's body weight, while the median number of harvested nucleated cells was 4.7 (range: 3.7,10.5) × 108/kg. All of the patients were engrafted. Myeloid engraftment occurred sooner after PBSCT than after BMT (median number of days to achieve absolute neutrophil counts (ANC) > 0.5 × 109/L; 11 and 15, respectively; p < 0.0001) and similar results were found for platelet engraftment (median number of days to achieve a platelet count of > 20 × 109/L; 12 and 21, respectively; p = 0.004). On the other hand, after PBSCT the absolute numbers of total circulating lymphocytes and lymphocyte subpopulations were not significantly different from those after BMT. The incidence of acute GvHD after PBSCT was the same as that after BMT, while chronic GvHD developed more frequently after PBSCT than after BMT (p = 0.005). In a pediatric population, the indications for PBSCT and BMT should be based on these findings in addition to regard for the donor's safety. [source] Development of a liquid chromatographic time-of-flight mass spectrometric method for the determination of unlabelled and deuterium-labelled , -tocopherol in blood componentsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2003Wendy L. Hall A method is described for the analysis of deuterated and undeuterated , -tocopherol in blood components using liquid chromatography coupled to an orthogonal acceleration time-of-flight (TOF) mass spectrometer. Optimal ionisation conditions for undeuterated (d0) and tri- and hexadeuterated (d3 or d6) , -tocopherol standards were found with negative ion mode electrospray ionisation. Each species produced an isotopically resolved single ion of exact mass. Calibration curves of pure standards were linear in the range tested (0,1.5,,M, 0,15,pmol injected). For quantification of d0 and d6 in blood components following a standard solvent extraction, a stable-isotope-labelled internal standard (d3- , -tocopherol) was employed. To counter matrix ion suppression effects, standard response curves were generated following identical solvent extraction procedures to those of the samples. Within-day and between-day precision were determined for quantification of d0- and d6-labelled , -tocopherol in each blood component and both averaged 3,10%. Accuracy was assessed by comparison with a standard high-performance liquid chromatography (HPLC) method, achieving good correlation (r2,=,0.94), and by spiking with known concentrations of , -tocopherol (98% accuracy). Limits of detection and quantification were determined to be 5 and 50,fmol injected, respectively. The assay was used to measure the appearance and disappearance of deuterium-labelled , -tocopherol in human blood components following deuterium-labelled (d6) RRR - , -tocopheryl acetate ingestion. The new LC/TOFMS method was found to be sensitive, required small sample volumes, was reproducible and robust, and was capable of high throughput when large numbers of samples were generated. Copyright © 2003 John Wiley & Sons, Ltd. [source] Gene transfer with modified polyethyleniminesTHE JOURNAL OF GENE MEDICINE, Issue S1 2004Antoine Kichler Abstract Branched and linear polyethylenimines (PEIs) have proven to be efficient and versatile agents for gene delivery in vitro. In addition, systemic administration of positively charged DNA/PEI complexes results in significant reporter gene expression in lungs. However, re-targeting of complexes to organs other than the lung is hampered by non-specific interactions of polyplexes with blood components and non-target cells. Thus, despite considerable transfectional activity, the properties of PEIs need to be further improved. Therefore, various modifications of PEIs have been explored in recent years. For example, to increase the circulation half-life of the DNA complexes, the surface charge of the particles was shielded by grafting hydrophilic polymers such as polyethylene glycols (PEGs) onto their surface. Alternatively, incorporation of certain ligands into the DNA complexes also resulted in charge shielding even without PEGylation. Herein, I review the most recent PEI derivatives, with a special focus on PEGylated and targeted polymers. Copyright © 2004 John Wiley & Sons, Ltd. [source] Influence of replacing brewers' grains with green tea grounds on feed intake, digestibility and ruminal fermentation characteristics of wethersANIMAL SCIENCE JOURNAL, Issue 2 2008Chuncheng XU ABSTRACT An experiment was conducted to examine feed intake, apparent digestibility, nitrogen balance, ruminal fermentation and blood components of wethers fed diets containing increasing levels of wet green tea grounds (WGTG). The experimental design was a 4 × 4 Latin square with four wethers in four 15-day periods. Wethers were allowed access to diets ad libitum, and allotted to one of four treatments in which WGTG replaced 0% (no WGTG added, CTG), 5% (low level, LBG), 10% (medium level, MTG), and 15% (high level, HTG) of total mixed ration (TMR) dry matter (DM) as wet brewers grains (WBG). All TMR silages were ensiled for 120 days and, irrespective of the WGTG addition, they were well preserved with a high lactic acid content, low pH and ammonia-N contents. There were no differences among treatments in feed intake, with the exception of ether extract intake (P = 0.032). Digestibilities for LTG and MTG treatments were not different from CTG. However, the organic matter, crude protein, acid detergent fiber and energy digestibilities for HTG treatment were lower than the CTG (P < 0.05). As the level of WGTG increased, nitrogen intake did not differ, but fecal nitrogen increased (P = 0.002), while urinary nitrogen decreased (P < 0.001). No differences among treatments were found in pH level and volatile fatty acids concentrations. However, the ruminal ammonia-N of the HTG silage was lower than for the CTG silage at all times (P < 0.05). Increasing concentrations of WGTG in the TMR silage decreased (P = 0.019) plasma urea nitrogen content. Therefore, the possible mixing proportion of WGTG for TMR silages can be 10% of the diet DM. [source] Do multiple blood transfusions predispose for a higher rate of non-blood-related infection complications?CLINICAL MICROBIOLOGY AND INFECTION, Issue 7 2002S. R. Leal Noval Allogeneic transfusions of red blood cell (RBC) concentrates have been related to an increase in postoperative infections. Leukocytes present in RBC units might have deleterious effects on the receptor immune system, provoking a state of immunosuppression that favors the development of postoperative infections (TRIM effect). The bioactive substances released by leukocytes in a time-dependent form, accumulating in blood components during storage, might be responsible for the TRIM effect. Multiple observational studies with logistic regression have demonstrated a direct relationship between transfusion and infection. However, several factors related to surgical difficulty and patient illness severity might act as strong confounding variables on the relationship studied. Randomized controlled trials designed to establish a causal relationship between transfusion and infection have yielded contradictory results. While we await new studies, allogeneic transfusions should be considered as a possible risk factor for postoperative infection. [source] | |||||||||||||