The current practice of red blood cell banking for transfusion medicine relies primarily on a six-week liquid storage. A growing demand for red blood cell (RBC) products has prompted the search for alternative preservation methods including dry storage. Being desiccation sensitive, attempts to recover RBCs from the dry state have failed. This dissertation offers a new mechanistic understanding of desiccation-induced cellular injury that is correlated with the oxidative state of the hemoglobin. The general hypothesis states that RBC desiccation is accompanied with non-physiological oxidation of hemoglobin and, consequently, the release of toxic products capable of compromising cellular recovery through oxidative injury. Data acquired for this dissertation demonstrates that water loss induces a drastic increase in the rate of hemoglobin oxidation, formation of intracellular reactive oxygen species (ROS), and hemolysis. Pharmacological treatments of the hemoglobins oxygen binding site reveal that hemoglobin-induced cellular injury is more prominent in RBC samples that are partially dehydrated (about 3.5 to 5.5 g H2O/g dry weight) than in samples that are relatively dry ( 2 g H2O/g dry weight). Furthermore, partially dehydrated RBC samples contain higher levels of oxidized lipids than more fully dried samples. This dissertation also examined the role that glucose and glutathione play in enhancing desiccation tolerance of RBCs. Glucose treatment (5 mmol/L) significantly reduced ROS formation and hemolysis levels in partially dehydrated RBC samples (5.8 0.3 g H2O/g dry weight), but not in samples that are relatively dry (2.8 0.5 g H2O/g dry weight). Treating RBCs with DL-buthionine-(S,R)-sulfoximine, a glutathione depleting agent, was correlated with reduced levels of desiccation-induced hemolysis. This study suggests that desiccation-induced oxidative injury in RBCs is water dependent corresponding to earlier stages of water loss, in which cells can retain metabolic activity. Pharmacological treatments at this stage can significantly affect cell recovery as demonstrated with modifying the hemoglobins oxygen binding site, glutathione depletion, and glucose supplementation. On the other hand, increased cytoplasmatic viscosity compromises biochemical reactions at lower residual moisture contents, and cellular injury is likely the result of physical and mechanical stress. These differences should be taken into consideration in the design of innovative approaches to RBC preservation.

Graduation date: 1992

The changes in plasma osmolality and percentage change in mean corpuscular volume accompanying dehydration (2~ and 4of body weight loss) were studied to assess the use of the venous hematocrit as a gauge of the percentage change in plasma volume. In vitro experiments were also conducted to verify the relationship between plasma osmolality and mean corpuscular volume.By utilizing the mean corpuscular hemoglobin concentration, calculation of the percentage change in mean corpuscular volume following dehydration showed a marked shrinkage of the red cells that was significantly related to the increase in plasma osmolality (r = - 0.99). Consequently, it was concluded that calculations of the percentage change in plasma volume during dehydration based on the change in venous hematocrit are subject to error unless corrections are made for alterations in mean corpuscular volume.Ball State UniversityMuncie, IN 47306

The objective of the research in this dissertation is to develop microsystem based separation technologies for whole cell cancer analysis using human whole blood as the input sample. This research work is carried out with two different approaches; one based on a miniaturized cascade magnetophoresis system and a second based on dielectrophoresis. The miniaturized systems can be fabricated using MEMS technologies combined with plastic fabrication techniques. The design, fabrication, packaging, and characterization of several versions of the magnetophoresis and dielectrophoresis microsystems for whole cell cancer analysis in human whole blood sample are presented. The developed magnetophoresis systems have demonstrated improved throughput in the removal of RBC from a human whole blood sample and its application to the separation of tagged cancer cells based on their surface expression level of a specific protein. The dielectrophoresis microsystem has successfully shown the ability to steer a blood stream between two outlets and to separate WBCs or cancer cells from a human whole blood sample. The developed microsystem based separation technologies can be further applied to the development of integrated system for cancer detection and treatments.

No description available.

Microhemodynamics is the study of blood flow in small vessels, usually on the order of 50 to 100 µm. The in vitro study of blood flow in small channels is analogous to the in vivo study of the microcirculation. At this scale the Reynolds and Womersly numbers are significantly less than 1 and the viscous stress and pressure gradient are the main determinant of flow. Blood is a non-homogeneous, non-Newtonian fluid and this complex composition and behavior has a greater impact at the microscale. A key parameter is the shear stress at the wall, which is involved in many processes such as platelet activation, gas exchange, embryogenesis and angiogenesis. In order to measure the shear rate in these blood flows the velocity profile must be measured. The measured profile can be characterized by the maximum velocity, the flow rate, the shear rate at the wall, or a shape parameter reflecting the bluntness of the velocity profile. The technique of micro-particle image velocimetry (µPIV) was investigated to measure the velocity profiles of blood microflows. The material of the channel, the type of tracer particles, the camera used, and the choice in data processing were all validated to improve the overall accuracy of µPIV as a blood microflow measurement method. The knowledge gained through these experiments is of immediate interest to applications such as the design of lab-on-a-chip components for blood analysis, analysis of blood flow behavior, understanding the shear stress on blood in the microcirculation and blood substitute analysis. Polymer channels were fabricated from polydimethylsiloxane (PDMS) by soft lithography in a clean room. PDMS was chosen for ease of fabrication and biocompatibility. The contacting properties of saline, water, and blood with various polymer channel materials was measured. As PDMS is naturally hydrophilic, surface treatment options were explored. Oxygenated plasma treatment was found to be less beneficial for blood than for water. The choice of camera and tracer particles were validated. Generally, for in vivo studies, red blood cells (RBCs) are used as tracer particles for the µPIV method, while for in vitro studies, artificial fluorescent micro particles are added to the blood. It is demonstrated here that the use of RBCs as tracer particles creates a large depth of correlation (DOC), which can approach the size of vessel itself and decreases the accuracy of the method. Next, the accuracy of each method is compared directly. Pulsed images used in conjunction with fluorescing tracer particles are shown to give results closest to theoretical approximations. The effect of the various post-processing methods currently available were compared for accuracy and computation time. It was shown that changing the amount of overlap in the post-processing parameters affects the results by nearly 10%. Using the greatest amount of correlation window overlap with elongated windows aligned with the flow was shown to give the best results when coupled with a image pre-processing method previously published for microflows of water. Finally the developed method was applied to a relevant biomedical engineering problem: the evaluation of blood substitutes and blood viscosity modifiers. Alginate is a frequently used viscosity modifier which has many uses in industry, including biomedical applications. Here the effect of alginate on the blood rheology, i.e., the shape of the velocity profile and the maximum velocity of blood flow in microchannels, was investigated. Alginate was found to blunt the shape of the velocity profile while also decreasing the shear rate at the wall. Overall, the accuracy of µPIV measurements of blood flows has been improved by this thesis. The work presented here has extended the known methods and accuracy issues of blood flow measurements in µPIV, improved the understanding of the blood velocity profile behavior, and applied that knowledge and methods to interesting, relevant problems in biomedical and biofluids engineering.

Blood-derived circulatory angiogenic cells (CACs) and resident cardiac stem cells (CSCs) have both been shown to improve cardiac function after myocardial infarction (MI) but the superiority of either cell type has long been an area of speculation with no definitive head-to-head trial. In this study, we compared the paracrine profile of human CACs and CSCs, alone or in combination. We characterized the therapeutic ability of these cells to salvage myocardial function in an immunodeficient mouse model of MI by transplanting these cells as both single and dual cell therapies seven days after experimental anterior wall MI. CACs and CSCs demonstrated unique paracrine repertoires with equivalent effects on angiogenesis, stem cell migration and myocardial repair. Combination therapy with both cell types synergistically improves post infarct myocardial function greater than either therapy alone. This synergy is likely mediated by the complementary paracrine signatures that promote revascularization and the growth of new myocardium.

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 163-174).

Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 125-131).

Στην παρούσα διπλωματική εργασία παρουσιάζεται μία μέθοδος αυτόματης αναγνώρισης των γεωμετρικών χαρακτηριστικών ερυθρών αιμοσφαιρίων από προσομοιωμένες εικόνες σκεδασμένου φωτός. Αρχικά παρουσιάζεται το ευθύ πρόβλημα σκέδασης ηλεκτρομαγνητικής ακτινοβολίας από ερυθρό αιμοσφαίριο, στη συνέχεια περιγράφονται οι τεχνικές με τις οποίες εκτελέστηκαν τα πειράματα για την επίλυση του αντίστροφου προβλήματος σκέδασης στο περιβάλλον προσομοίωσης του Matlab και τέλος προτείνεται μία μέθοδος έτσι ώστε η αναγνώριση να είναι δυνατή αυτόματα και σε πραγματικό χρόνο. / Geometric features recognition of red blood cells through scattered light pictures.