• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 129
  • 80
  • 45
  • 8
  • 8
  • 7
  • 6
  • 6
  • 3
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 338
  • 229
  • 107
  • 76
  • 43
  • 35
  • 35
  • 35
  • 34
  • 34
  • 32
  • 30
  • 28
  • 27
  • 22
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Novel cryoprotective agents to improve the quality of cryopreserved mammalian cells

Al-Otaibi, Noha January 2018 (has links)
Cryopreservation is a promising approach to long-term biopreservation of living cells, tissues and organs. The use of cryoprotective agents (CPAs) in combination with extremely low temperatures is mandatory for optimum biopreservation. CPAs (e.g., glycerol, trehalose, dimethyl sulphoxide (DMSO)), however, are relatively cytotoxic and compromise biopreserved cell quality. This is usually resultant in oxidative damage, diminishing cell functionality and survival rate. The growing market of cell therapy medicinal products (CTMPs) demands effective cryopreservation with greater safety, of which the currently available CPAs are unable to provide. The present study was aimed at developing cryomedia formulation to enhance the cryopreservation of nucleated and anucleated mammalian cells. Here, eleven compounds of a polyol nature were selected and examined for their cryoprotective properties. These compounds are derived from plants and honey, thereby ensuring their safety for human consumption. The selection was based on their molecular structure and chemical properties. Here, the presented study is divided into three main phases: 1) Screening the compounds panel for cryo-additive effects on cells during and post-cryopreservation and optimising the dose response and time course for trehalose and glycerol with and without the novel compounds; 2) Assessing the influence of biophysical criteria on biospecimen cryopreservation (e.g., biosampling procedure, cell age, donor age); 3) Establishing the mechanisms of action underpinning the modulatory effect of novel CPAs on biological pathways during cryopreservation. For the stated purposes, red blood cells (RBCs) obtained from sheep and humans were used to screen the compounds for novel cryo-additive agents. Cryosurvival rate was employed as an indication of the compounds' cryoprotective performance. Cellular biochemical profiles, including lipid and protein oxidative damage as well as key redox enzymatic activities (e.g., lactate dehydrogenase (LDH), glutathione reductase (GR)) were measured. The study revealed that nigerose (Nig) and salidroside (Sal) were significantly effective in protecting cells during the freeze-thaw cycle and recovery phases. Both compounds promoted the activity of GR and reduced oxidative stress mirrored by diminished LDH activity. This was also reflected in the protein and lipid oxidation levels, which was limited to a comparable level with the cells' prior freezing. Further studies on human leukaemia (HL-60) were carried out to elucidate the molecular and biological pathways associated with cryodamage and the modulatory effects of adding novel CPAs. The proteome profile and the corresponding biological functions were evaluated and iii showed that Nig and Sal protected cells against cryodamage. The additive compounds (Nig and Sal) demonstrated a unique and overlapping modulation effect pattern. Nig was found to highly influence proteins engaged with metabolic and energetic pathways, whereas Sal greatly affected nuclear and DNA-binding proteins. The current study concluded that novel CPAs have high potency in protecting cells and each compound has a unique effect on the cellular proteome. These features can be applied to designing cryomedia formulae with higher protective efficiency for targeted applications in cell based therapy and biopharmaceutical industries.
142

Plasma as a Therapeutic Principle in Clinical Practice : With Special Reference to Sweden

Norda, Rut A C January 2007 (has links)
<p>The newly established Swedish Apheresis Registry makes it possible to do national inter-center comparisons. This study was undertaken to describe and analyze the use of therapeutic apheresis and the adverse effects in such therapy. The special case of plasma exchange as rescue therapy in multi-organ failure, including renal failure, was also studied. In Sweden, plasma for transfusion is prepared and stored to ensure rapid availability. Due to new EU legislation, validation of such plasma was performed. </p><p>The analysis indicated that the use of therapeutic apheresis was in line with recommendations of other international societies. The frequency and types of adverse effects were comparable to those reported in other studies from analogous time periods. Compared with other countries, it appears that more therapeutic resources are available in Sweden and that there is a lower frequency of adverse effects in specific procedures. No fatalities were reported. The unique comparison of differences between centers regarding plasma exchange identified areas for further improvement.</p><p>The study on plasma exchange as rescue therapy in severe sepsis or septic shock is the second largest reported. The result was promising, with a survival rate of 82%. The rapid availability of plasma for transfusion appears to be of clinical importance in patients with early coagulopathy and severe trauma but the present selection and storage procedures for plasma lead to a time-dependent increase of the number of units with cold-induced activation of the contact system and C1 inhibitor consumption before day 14. Improvements of plasma quality can be attained by using plasma from male donors only and by reducing the storage time from 14 to 7 days. </p><p>Further studies are needed to define the role of plasma exchange in severe sepsis/septic shock, to evaluate the outcome of each patient’s treatment and to establish the indications for the transfusion of plasma.</p>
143

Plasma as a Therapeutic Principle in Clinical Practice : With Special Reference to Sweden

Norda, Rut A C January 2007 (has links)
The newly established Swedish Apheresis Registry makes it possible to do national inter-center comparisons. This study was undertaken to describe and analyze the use of therapeutic apheresis and the adverse effects in such therapy. The special case of plasma exchange as rescue therapy in multi-organ failure, including renal failure, was also studied. In Sweden, plasma for transfusion is prepared and stored to ensure rapid availability. Due to new EU legislation, validation of such plasma was performed. The analysis indicated that the use of therapeutic apheresis was in line with recommendations of other international societies. The frequency and types of adverse effects were comparable to those reported in other studies from analogous time periods. Compared with other countries, it appears that more therapeutic resources are available in Sweden and that there is a lower frequency of adverse effects in specific procedures. No fatalities were reported. The unique comparison of differences between centers regarding plasma exchange identified areas for further improvement. The study on plasma exchange as rescue therapy in severe sepsis or septic shock is the second largest reported. The result was promising, with a survival rate of 82%. The rapid availability of plasma for transfusion appears to be of clinical importance in patients with early coagulopathy and severe trauma but the present selection and storage procedures for plasma lead to a time-dependent increase of the number of units with cold-induced activation of the contact system and C1 inhibitor consumption before day 14. Improvements of plasma quality can be attained by using plasma from male donors only and by reducing the storage time from 14 to 7 days. Further studies are needed to define the role of plasma exchange in severe sepsis/septic shock, to evaluate the outcome of each patient’s treatment and to establish the indications for the transfusion of plasma.
144

OUTCOMES ASSOCIATED WITH BLOOD COMPONENT TRANSFUSION IN ADULT TRAUMA PATIENTS

Jones, Allison R 01 January 2015 (has links)
The purpose of this dissertation was to evaluate outcomes associated with blood component (BC) transfusion in adult trauma patients. Specific aims were to: 1) explore the relationship between traumatic injury, hemorrhage, and BC transfusion, focusing on consequences of the component storage lesion through presentation of a conceptual model; 2) systematically review research literature comparing outcomes of massively transfused major trauma patients based on ratios of BCs received; 3) evaluating the relationship between type of blood transfusion trauma patients received (whole blood versus BCs) and mortality likelihood after controlling for demographic and clinical variables; 4) evaluating the relationship between volume and ratio of BCs transfused to trauma patients and development of inflammatory complications (ICs) after controlling for demographic and clinical variables. Specific aim one was addressed through the development of a conceptual model, depicting the current state of knowledge regarding the storage lesion, and short-/long-term outcomes of traumatic injury, hemorrhage, and blood transfusion. The second specific aim was addressed through a systematic review of studies that grouped critically injured, massively transfused patients based on ratios of BCs they received, and compared clinical outcomes among groups. Findings from this analysis revealed increased survival likelihood with massive transfusion of BCs in a 1:1:1 (packed red blood cells [PRBCs], fresh frozen plasma [FFP], platelets [PLTs]) fashion. The third specific aim involved a secondary analysis of the National Trauma Data Bank to evaluate the relationship between type of transfusion trauma patients received (whole blood versus BCs) and mortality. Patients who received BCs experienced a higher mortality likelihood compared with those who received whole blood. The fourth specific aim was addressed through a secondary analysis of the Inflammation and Host Response to Injury Trauma-Related Data Base, to evaluate the relationship between volume and ratio of BCs transfused and development of ICs in patients with major trauma. Findings revealed that total transfused volume of PRBCs, injury severity, and comorbidities were associated with development of ICs. There were no differences in time to complication between PRBCs:FFP or PRBCs:PLTs ratio groups.
145

The role of neutrophil primining and neutrophil antibodies in the pathogenesis of Transfusion-Related Acute Lung Injury (TRALI)

Yoke Lin Fung Unknown Date (has links)
No description available.
146

Haemostatic changes in plasma for transfusion during preparation and storage /

Suontaka, Anna-Maija, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.
147

Storage and transfusion of platelets in vitro and in vivo studies in healthy volunteers and in allogeneic hematopoetic progenitor cell transplant recipients /

Diedrich, Beatrice, January 2009 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009.
148

Η επίδραση της μετάγγισης αίματος στα Τ ρυθμιστικά κύτταρα ασθενών που υποβάλλονται σε μερική ή ολική αρθροπλαστική γόνατος ή ισχύου

Σπαντιδέα, Παναγιώτα 14 October 2013 (has links)
Από την δεκαετία του '70 είναι γνωστό ότι οι αλλογενείς μεταγγίσεις αίματος (ABT) προκαλούν ανοσοκαταστολή, ωστόσο, μετά το 1990 έγινε γνωστό ότι για το φαινόμενο αυτό ευθύνεται ο Τ λεμφοκυτταρικός πληθυσμός των ρυθμιστικών κυττάρων (Tregs). Στην παρούσα εργασία, μελετήθηκε η επίδραση της μετάγγισης σε ασθενείς που είχαν υποβληθεί σε ολική ή μερική αρθροπλαστική γόνατος ή ισχίου, στον πληθυσμό των φυσικών (nTreg) και επαγώγιμων (iTreg) Τ ρυθμιστικών κυττάρων. Στους ίδιους ασθενείς μελετήθηκε και η αλλαγή προτύπου στην έκκριση των κυτταροκινών. Συλλέχθηκαν δείγματα ολικού αίματος από 46 ασθενείς, 7 άντρες και 39 γυναίκες. Από αυτούς, οι 36 ασθενείς έλαβαν μετάγγιση (Group1) ενώ οι 10, δεν έλαβαν. Η συλλογή των δειγμάτων έγινε πριν την εγχείρηση (BS), αμέσως μετά το χειρουργείο (Day0), μια εβδομάδα μετά (Day7), ένα μήνα μετά (1month) και κατά τον επανέλεγχο των ασθενών (>3months). Στα δείγματα έγινε απομόνωση των PBMC και καθορίστηκε το ποσοστό των CD4+CD25+Foxp3+ και CD4+CD25high/+CD127low/- Tregs με την μέθοδο FACS ενώ στο πλάσμα καθορίστηκαν τα επίπεδα των κυτταροκινών με τις μεθόδους Cytometric Bead Array (CBA) και ELISA. Επιπρόσθετα, μελετήθηκε η λειτουργικότητας των Treg από δείγμα αίματος ασθενών μέσα στην πρώτη εβδομάδα μετά το χειρουργείο. Καλλιεργήθηκαν διάφοροι λόγοι Tregs: Teff για 72 ώρες, παρουσία PHA και CFSE. Με την μέθοδο Cytometric Bead Array (CBA) καθορίστηκαν τα επίπεδα των κυτταροκινών IL-2, IL-4, IL-5, IL-6, IL-10, TNF-α, IFN-γ ενώ με την μέθοδο της ELISA καθορίστηκαν τα επίπεδα των TNF-α και των υποδοχέων TNF-RI(p55/p60) και TNF-RII(p75/p80) καθώς επίσης και οι TGF-β1 και TGF-β2. Από τα πειράματα προέκυψε ότι οι πληθυσμοί τόσο των φυσικών CD4+CD25+Foxp3+ όσο και των επαγώγιμων CD4+CD25high/+CD127low/- Tregs, αυξάνονται μετά το χειρουργείο (day 0), μετά την μετάγγιση, ενώ μειώνονται την πρώτη εβδομάδα μετά το χειρουργείο. Αντίθετα αποτελέσματα παρατηρήθηκαν στους ασθενείς οι οποίοι υποβλήθηκαν σε χειρουργείο αλλά δεν μεταγγίστηκαν. Με τα πειράματα λειτουργικότητας, φάνηκε ότι τα Tregs ήταν λειτουργικά και ικανά να προκαλούν αναστολή του πολλαπλασιασμού των Teff. Σχεδόν όλες οι κυτταροκίνες που αναλύθηκαν, οι IL-2, IL-4, IL-5, IL-6, IL-10, TNF-α, IFN-γ, ο υποδοχέας TNF-RI(p55/p60) και TNF-RII(p75/p80) και TGF-β2 εμφάνισαν αύξηση μετά το χειρουργείο, μετά την μετάγγιση. Ωστόσο, μόνο η αύξηση της IL-6, και των υποδοχέων TNF-RI(p55/p60) και TNF-RII(p75/p80) ήταν στατιστικώς σημαντική μετά το χειρουργείο, μετά την μετάγγιση. Τα επίπεδα του TGF-β1 μειώθηκαν μετά το χειρουργείο, μετά την μετάγγιση (Th3 απόκριση). Συμπερασματικά, τα ποσοστά των Tregs αυξήθηκαν στους ασθενείς που υποβλήθηκαν σε αρθροπλαστική και μεταγγίστηκαν. Οι πληθυσμοί των Tregs παρέμειναν αυξημένοι μέχρι και τον πρώτο μήνα μετά το χειρουργείο. Τα Tregs είναι λειτουργικά και ικανά να καταστέλλουν τον πολλαπλασιασμό των Teff, παρουσία PHA. Μετά το χειρουργείο, ύστερα από μετάγγιση, τα επίπεδα των IL-6, TNF-RI και TNF-RII αυξάνονται ως αντίδραση κατά του μοσχεύματος. Μετά την εγχείρηση (day 0) και μετά από μετάγγιση, οι ασθενείς αναπτύσσουν Th1 απόκριση και πολλαπλασιασμό των Tregs. Σταδιακά, τα Tregs καταστέλλουν τις προφλεγμονώδης αποκρίσεις μέχρι να επανέλθει η ισορροπία των ληπτών μετά την εγχείρηση. / Clinical and experimental studies have established that allogeneic blood transfusion (ABT) can cause immunosuppression. In this work we determined whether and to which extend Tregs contribute to this effect. Material and methods: Heparinized peripheral blood samples were collected from 46 patients (7 male and 39 female, age 28-88 years) that underwent joint replacement surgery. The samples were collected immediately before surgery (BS) and after surgery (AS) on days 0, 7, 1 month, and 3 months to 1 year. Thirty six patients received ABT and 10 did not. PBMC were isolated and the numbers and % of CD4+CD25+Foxp3+ Tregs and CD4+CD25high/+CD127low/- Tregs were determined by FACS. Tregs and T effectors (Teff) were isolated from patients on days 0-7 and Treg functional assays were performed by culturing Tregs with PHA-stimulated Teff at different ratios for 72h with CFSE, and analyzed by FACS. Cytokine serum level determined with Cytometric Bead Array (CBA) for IL-2, IL-4, IL-5, IL-6, IL-10, TNF-α, IFN-γ and ELISA for TNF-α, the receptor TNF-RI(p55/p60) and II(p75/p80), TGF-β1 and β2. Results: Both, natural (CD4+CD25+Foxp3+) and inducible (CD4+CD25high/+CD127low/-) Tregs increased in day 0 and decreased in day 7 until BS levels, after ABT. Opposite results (small reduction) observed in patients without ABT. With functional assays proved that Tregs are functional and suppress the T-cell proliferation. IL-2, IL-4, IL-5, IL-6, IL-10, TNF-α, IFN-γ, the receptor TNF-RI(p55/p60) and II(p75/p80), TGF-β1 and β2 increased after the surgery, after ABT. IL-6, TNF-RI(p55/p60) and II(p75/p80) levels increased with SSD after the surgery, after ABT. TGF-β1 levels decreased in day 0 until BS levels (Th3 response). Th3 cells growth from CD4+CD25- FoxP3- Th0 peripheral cells. Th3 prevents maturation of DCs, Th2 T-cells. Induce the TGF-β secretion and inhibit IL-2 and antibodies secretion. Conclusion: In patients underwent scheduled joint replacement surgery, Tregs increased after ABT until 1 month and are functional and suppress Teff proliferation under PHA condition. IL-6, TNF-RI and TNF-RII are activation markers of immune system and suppressed after ABT. In day 0, IL-6, TNF-RI and II levels increased as a reaction graft against host’s antigen. After surgery (day 0), patients develop Th1 response and Tregs proliferation, after ABT. Gradually, Tregs suppress the proinflammatory responses until the balance in the recipient, after the surgery.
149

Desmopressin for treatment of thrombocytopenia or platelet dysfunction

Desborough, Michael J. R. January 2017 (has links)
The objective of the work presented in this thesis was to explore the role of potential alternatives to platelet transfusions and specifically to investigate whether desmopressin could be used for treatment of thrombocytopenia or platelet dysfunction. Patients with thrombocytopenia or platelet dysfunction are often treated with platelet transfusions to treat or prevent bleeding. However the evidence for the efficacy of platelet transfusion is limited and there is some evidence of harm. I have focused on thrombocytopenic patients with haematological malignancies or critically ill patients, who are amongst the groups most commonly treated with platelet transfusions. The aims of this research were to determine: 1. If levels of Von Willebrand factor (VWF) or other measures of haemostasis are predictive of bleeding in severe thrombocytopenia; 2. Whether VWF compensates for thrombocytopenia in vitro; 3. The evidence for the efficacy of desmopressin in all patients undergoing surgery or invasive procedures; 4. The evidence for desmopressin for platelet dysfunction or thrombocytopenia; 5. If it is feasible to use desmopressin to treat critically ill thrombocytopenic patients in a clinical trial. To identify derangements of haemostasis that may signify candidates for alternatives to platelet transfusions, I analysed blood samples from an observational trial of fifty patients with haematological malignancies and profound thrombocytopenia due to intensive chemotherapy. I used a panel of tests to investigate measures of primary haemostasis, thrombin generation, cross-linked fibrin formation and fibrinolysis. Using multivariable logistic regression, I found no consistent correlation between any measures of haemostasis and the risk of clinically significant bleeding. VWF antigen levels were the best predictor of clinically significant bleeding on the same day (odds ratio 0.31, 95% confidence interval 0.10 to 0.98, p=0.047) but were not predictive of severe bleeding over the 24 hours after the test (odds ratio 0.48, 95% confidence interval 0.10 to 2.34, p=0.36). In a separate set of experiments, I evaluated thrombus formation under flow in thrombocytopenia. This technique was sensitive to the platelet count . Addition of exogenous VWF to thrombocytopenic blood resulted in improvement in thrombus formation, suggesting that agents that affect or influence VWF pathways might have a role. Desmopressin can be used to increase VWF levels, so leading on from my laboratory experiments; I used systematic reviews and meta-analyses to assess whether desmopressin could be used in unselected patients to reduce bleeding peri-operatively. I identified 62 randomised controlled trials. Overall there was no evidence of benefit for administering desmopressin to unselected patients. However further analysis of eleven randomised controlled trials that focused on patients with platelet dysfunction found that desmopressin resulted in transfusion of fewer units of red cells (equivalent to a 25% reduction compared to control), less blood loss (equivalent to a 23% reduction compared to control) and a lower risk of requiring a re-operation due to bleeding (Peto odds ratio 0.39, 95% confidence interval 0.18 to 0.84). There was no evidence for an increase in thrombotic events. There was no randomised controlled trial evidence for perioperative desmopressin for patients with thrombocytopenia. These specific research gaps were addressed by designing new clinical trials. I have commenced a randomised controlled feasibility trial of desmopressin versus placebo for critically ill patients with thrombocytopenia undergoing invasive procedures. This trial is ongoing and is the first randomised trial evaluating peri-procedural desmopressin in thrombocytopenia. The programme of work arising from this research has the potential to benefit a large number of patients by preventing bleeding and reducing exposure to allogeneic blood components such as platelets. The results presented in this thesis are exploratory but are an important step on a path towards larger trials using desmopressin as an alternative, or adjunct to platelet transfusion.
150

Detektion av alloantikroppar hos nyligt transfunderade DAT-positiva patienter : Utvärdering med en experimentell in vitro modell / Detection of Alloantibodies in Recently Transfused DAT-Positive Patients : Evaluation with an Experimental in vitro Model

Bixo, Mi January 2018 (has links)
No description available.

Page generated in 0.0999 seconds