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Dielectrophoretic characterization of particles and erythrocytesSrivastava, Soumya Keshavamurthy 07 August 2010 (has links)
Medical lab work, such as blood testing, will one day be near instantaneous and inexpensive via capabilities enabled by the fast growing world of microtechnology. In this research study, sorting and separation of different ABO blood types have been investigated by applying alternating and direct electric fields using class=SpellE>dielectrophoresis in microdevices. Poly(dimethylsiloxane) (PDMS) microdevices, fabricated by standard photolithography techniques have been used. Embedded perpendicular platinum (Pt) electrodes to generate forces in AC dielectrophoresis were used to successfully distinguish positive ABO blood types, with O+ distinguishable from other blood types at >95% confidence. This is an important foundation for exploring DC dielectrophoretic sorting of blood types. The expansion of red blood cell sorting employing direct current insulative class=SpellE>dielectrophoresis (DC-iDEP) is novel. Here Pt electrodes were remotely situated in the inlet and outlet ports of the microdevice and an insulating obstacle generates the required dielectrophoretic force. The presence of ABO antigens on the red blood cell were found to affect the class=SpellE>dielectrophoretic deflection around the insulating obstacle thus sorting cells by type. To optimize the placement of insulating obstacle in the microchannel, COMSOL Multiphysics® simulations were performed. Microdevice dimensions were optimized by evaluating the behaviors of fluorescent polystyrene particles of three different sizes roughly corresponding to the three main components of blood: platelets (2-4 µm), erythrocytes (6-8 µm) and leukocytes (10-15 µm). This work provided the operating conditions for successfully performing size dependent blood cell insulator based DC dielectrophoresis in PDMS microdevices. In subsequent studies, the optimized microdevice geometry was then used for continuous separation of erythrocytes. The class=SpellE>microdevice design enabled erythrocyte collection into specific channels based on the cell’s deflection from the high field density region of the obstacle. The channel with the highest concentration of cells is indicative of the ABO blood type of the sample. DC resistance measurement system for quantification of erythrocytes was developed with single PDMS class=SpellE>microchannel system to be integrated with the DC- class=SpellE>iDEP device developed in this research. This lab-on-a-chip technology application could be applied to emergency situations and naturalcalamities for accurate, fast, and portable blood typing with minimal error.
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DNA Encoded Libraries (DEGL) of Glycan Antigens to Detect Antibodies: An Approach Towards Next Generation Functional GlycomicsParameswaran, Aishwarya 08 August 2017 (has links)
Structure and functional study of glycans are highly challenging due to the difficulties in analyzing glycans and limited availability of samples for study. These limitations could be resolved by attaching DNA barcode to the glycan, which virtually represent glycan in further application, by increasing the sensitivity of detection by polymerase chain reaction (PCR), requiring minimal samples for analysis. Assuming bigger arena of DNA Encoded Glycan Libraries (DEGL) in future, we propose here a method for uniquely coding all glycans using computer program that can convert the structural information of glycans to DNA barcode. A unique and universal coding for glycans will benefit both synthesis and analysis of DEGLs. As a proof of principle study, a small DNA Encoded Glycan Library (DEGL) of blood and globo series glycan antigen and its application was demonstrated in detecting blood group and breast cancer from plasma.
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Le groupe sanguin canin Dal : prévalence et immunogénicitéGoulet, Stéphanie 08 1900 (has links)
L’objectif de cette étude est de déterminer l’importance clinique de l’antigène érythrocytaire canin
Dal, en investiguant sa prévalence, son mode d’héritabilité et son immunogénicité.
Un total de 1230 chiens a été recruté à travers l’Amérique du Nord et typés pour le Dal en utilisant
des allo-anticorps polyclonaux et une technique sur colonne de gel. Des individus Dal-négatifs ont été
identifiés chez les Dalmatiens (n=15/128), Doberman Pinschers (n=183/432), Shih Tzus (n=12/21),
chiens de races croisées (3/122), Beagles (2/100), Lhasa Apso (1/3) et Bichon Frisé (1/6). Six donneurs
de sang Dal-négatifs ont été identifiés, dont 5 Doberman Pinschers (1/228 donneurs d’une autre
race). Tous les autres chiens testés étaient Dal-positifs (n=418). La rareté du sang Dal-négatif place les
chiens Dal-négatifs à risque d’incompatibilité transfusionnelle lors de transfusions multiples. Cette
étude est la première à identifier des individus Dal-négatifs chez des chiens de race autre que
Dalmatien et à établir le mode d’héritabilité du Dal, soit autosomal dominant.
Par la suite, 2 Beagles Dal-négatifs ont été sensibilisés spécifiquement pour le Dal en recevant une
transfusion Dal-positif. Suivant la sensibilisation, des allo-anticorps anti-Dal ont été détectés à partir
du 4ième jour post-transfusion et sont demeurés détectables jusqu’à 2 ans post-transfusion. Les titres
d’agglutination maximaux (1:64 et 1:1024) ont été atteints 2 et 1 mois post-transfusion chez le chien
#1 et le chien #2, respectivement. Cette étude a confirmé l’immunogénicité du Dal tout en ayant
généré une quantité considérable d’allo-anticorps anti-Dal permettant de futurs typages sanguins
Dal. / The purpose of this study was to determine the clinical importance of the Dal canine erythrocyte
antigen by investigating its prevalence, its mode of inheritance and its immunogenicity.
A total of 1230 dogs recruited from North America were blood typed for Dal applying a gel column
technique using polyclonal canine anti-Dal sera. Dal-negative dogs were identified mostly in
Dalmatians (15/128), Dobermans Pinschers (183/432) and Shih Tzus (12/21), and sporadically in
mixed breed dogs (3/122), Beagles (2/100), Lhasa Apso (1/6) and Bichon Frise (1/3). All other dogs
tested were Dal-positive (n= 418). Six Dal-negative blood donors were found, including 5 Doberman
Pinschers (1/228 non-Dalmatian and non-Doberman Pinscher blood donors). The scarcity of Dal-negative
blood donors puts Dal-negative patient at higher risk of transfusion incompatibility if
requiring multiple blood transfusions. This study was the first to identify Dal-negative dogs in other
breeds than Dalmatians and to establish an autosomal dominant mode of inheritance of the
Dal-positive phenotype.
Secondly, 2 Dal-negative healthy research Beagles were sensitized specifically for Dal with a
Dal-positive packed red blood cell transfusion. Following sensitization, anti-Dal alloantibodies were
detected as early as 4 days post-transfusion and remained detectable 2 years post-transfusion, with
maximum agglutination titers (1:1024 and 1:64) reached respectively 1 and 2 months posttransfusion
in dog #2 and dog #1. Our study confirmed the immunogenicity of the Dal and allowed
banking of a considerable amount of polyclonal antisera for further Dal blood typing.
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Prevalência dos tipos sanguíneos A, B e AB em felinos selvagens neotropicais nativos do BrasilBisca, Jacqueline Muniz January 2017 (has links)
Orientador: Carlos Roberto Teixeira / Resumo: Os felinos selvagens neotropicais habitam as Américas do Sul e Central, porém apenas oito espécies são nativas do Brasil. Foi reportado em felinos selvagens o mesmo sistema AB sanguíneo de felinos domésticos, composto por três tipos, A, B e o mais raro AB. O objetivo deste trabalho foi realizar tipagem sanguínea nas espécies de felídeos neotropicais brasileiras através do teste em cartão e teste de hemaglutinação em tubo de ensaio. Comparar o uso destas técnicas e descrever a prevalência dos tipos sanguíneos A, B e AB nestas espécies. Foram coletadas 42 amostras de seis diferentes espécies de felinos selvagens neotropicais, sendo dez Leopardus tigrinus, sete Leopardus weidii, oito Leopardus pardalis, dois Puma yagouaroundi, quatro Puma concolor e 11 Panthera onca. Todos os animais pertencentes ao gênero Panthera e Leopardus foram positivos para o tipo sanguíneo A em ambos os testes realizados. Já os animais pertencentes ao gênero Puma, foram positivos para o tipo B. Não houve problemas para tipagem através do método em cartão, sugerindo uma boa aplicabilidade na tipagem sanguínea em felídeos. / Abstract: Neotropical wild felids habit South and Central America, but only eight species are native to Brazil. The same AB blood system of domestic cats has been reported in wild cats, consisting of three types, A, B and the rarest AB. The objective of this work was to perform blood typing in Brazilian neotropical wild cats species through the card test and hemagglutination test in a test tube. Compare the use of these techniques and to describe the prevalence of blood types A, B and AB in these species. A total of 42 samples of six different Neotropical wild cat species were collected: ten Leopardus tigrinus, seven Leopardus weidii, eight Leopardus pardalis, two Puma yagouaroundi, four Puma concolor and 11 Panthera onca. All animals belonging to the genus Panthera and Leopardus were positive for blood type A in both tests. However, the animals belonging to the Puma genus were positive for type B. There were no problems for typing through the cardboard method, suggesting a good applicability in feline blood typing. / Mestre
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Avancées en médecine transfusionnelle féline : de l’optimisation du prélèvement à la découverte de nouveaux antigènes érythrocytairesBinvel, Marie 07 1900 (has links)
La médecine transfusionnelle féline a connu une croissance exponentielle au cours des dix dernières
années. La découverte du système de groupes sanguins AB et la meilleure compréhension des mécanismes d’incompatibilité donneur-receveur, ainsi que le développement de systèmes de collecte adaptés au chat et de techniques de typage sanguin au chevet du patient ont permis d’améliorer la sécurité des transfusions.
Notre travail s’est intégré dans cette volonté d’optimiser la sécurité des transfusions sanguines chez le
chat en se concentrant sur deux aspects différents : le prélèvement de sang et les antigènes érythrocytaires à l’origine d’incompatibilités donneur-receveur non expliquées par le système AB.
Dans un premier temps, un système de collecte de sang adapté au chat a été fabriqué afin de permettre
un prélèvement fermé et autoriser le stockage des produits sanguins. Ce système a été comparé à un
système ouvert composé de seringues. Le système fermé apparaît adapté au prélèvement de sang car
aucune différence significative n’a été enregistrée dans les paramètres vitaux des donneurs après le
prélèvement, le succès du prélèvement, ou la qualité du produit sanguin en termes de contamination
bactérienne et d’hémolyse, entre les deux systèmes. Le net avantage du système fermé est qu’il assure un temps de prélèvement plus rapide que le système ouvert.
Dans un second temps, en réalisant des tests de compatibilité chez 258 chats de type A, nous avons montré que la probabilité de détecter des incompatibilités entre deux chats de groupe A sélectionnés
aléatoirement était de 3.9 %, et que 7 % des chats de groupe A présentaient des allo-anticorps naturels
extérieurs au système AB. Sept des 18 allo-anticorps naturels détectés ont été utilisés comme réactifs lors d’un typage sanguin extensif. Les analyses sur l’accord des résultats du typage obtenus avec les différents réactifs ont permis d’identifier cinq nouveaux antigènes érythrocytaires félins différents, nommés FEA 1 à FEA 5 (pour feline erythrocyte antigen), dont l’hérédité, la prévalence, la distribution géographique et par race, ainsi que l’immunogénicité restent encore à déterminer. / Feline transfusion medicine has grown exponentially over the past decade. The discovery of the AB blood
group system and the better understanding of the mechanisms of donor-receiver incompatibility, as well
as the development of cat-friendly collection systems and bedside blood typing techniques have improved transfusion safety. Our work has been part of this effort to optimize the safety of blood transfusions in cats by focusing on two different aspects: blood collection and red blood cell antigens that cause donor-recipient incompatibilities unexplained by the AB system.
First, a blood collection system adapted to the cat was manufactured to allow collection in a closed-system and storage of blood products. This system was compared to an open system consisting of syringes. The closed system appeared well-adapted for feline blood collection because no significant difference was found in the vital parameters of the donors after collection, the success of the collection, or the quality of the blood product in terms of bacterial contamination and hemolysis. The distinct advantage of the closed system was that it provided a shorter duration of collection than the open system.
Secondly, based on the systematic crossmatches of 258 cats, we showed that the probability of detecting
incompatibilities by randomly crossmatching two type A cats was 3.9 %, which resulted in at least 7 % of
type A cats having naturally occurring alloantibodies outside the AB blood group system. Seven of the 18
detected naturally occurring alloantibodies were used as reagents in an extensive blood typing.
Comparison of the results obtained from this extensive blood typing supports the existence of five,
presumably different, new feline erythrocyte antigens, named FEA 1 to FEA 5, whose mode of inheritance,
geographical and breed distribution, frequency and immunogenicity have yet to be determined.
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