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Circulating Blood (circulating + blood)
Selected AbstractsHemocompatibility, biocompatibility, inflammatory and in vivo studies of primary reference materials low-density polyethylene and polydimethylsiloxane: A reviewJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 5 2001Claire Bélanger, Marie Abstract In 1984, low-density polyethylene (LDPE) and polymethylsiloxane (PDMS), two primary reference materials (PRM), were made available by the National Heart, Lung, and Blood Institute (NHLBI) as discriminatory tools for the validation of standardized and novel in vitro and in vivo tests in the evaluation of biomaterials. This article reviews the results and conclusions obtained by several studies investigating the hemocompatibility, in vitro biocompatibility, inflammatory response, and in vivo tissue reactions of these two reference materials. Variable results obtained with LDPE and PDMS in ex vivo hemocompatibility studies were attributed to the type of animal model used, the flow velocity of the circulating blood, the time of exposure, and the methodology used to measure blood cell adhesion or activation at the surface of the materials. In contrast, both the LDPE and PDMS appeared to be suitable reference materials when used in in vitro biocompatibility, inflammatory response, and in vivo studies. However, caution must be taken when interpreting the results, because gamma sterilization of these two materials as well as their origin (for example PDMS) are two critically important factors. In conclusion, we see a definite need for standardized hemocompatible parameters and better high-quality hemocompatibility studies on PRM. This review also suggests other materials as potential PRM candidates, namely, Biomer® and IntramedicÔ polyethylene. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 467,477, 2001 [source] Why ,2 -antiplasmin must be converted to a derivative form for optimal functionJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2007K. N. LEE Summary.,Background:,Human ,2 -antiplasmin (,2AP), the primary inhibitor of fibrinolysis, is secreted from the liver into plasma as a 464-residue protein with Met as the N-terminus. An R6W polymorphism has been suggested to affect fibrinolytic rate. Within circulating blood, antiplasmin-cleaving enzyme (APCE) cleaves Met-,2AP(R6) faster than Met-,2AP(W6) at the Pro12,Asn13 bond to yield Asn-,2AP. Objectives:,To compare Met-,2AP(R6), Met-,2AP(W6) and Asn-,2AP for crosslinking with fibrin and the ability to protect fibrin from digestion by plasmin. Methods and results:,Asn-,2AP utilizes Gln2 (Gln14 in Met-,2AP) to become crosslinked to fibrin approximately twelvefold faster than Met-,2AP(R6) or Met-,2AP(W6), and this enhances the resistance of fibrin to plasmin. All three forms of ,2AP inhibit plasmin at identical rates. The N-terminal 12-residue peptide of Met-,2AP slows crosslinking of Met-,2AP(R6) or Met-,2AP(W6) by limiting access of factor XIIIa to Gln14 rather than shifting crosslinking to other Gln residues. Edman sequencing and mass analyses of tryptic peptides from each ,2AP crosslinked with 5-(biotinamido)pentylamine showed Gln14 as the only major crosslinking site. Residues 5,8, GRQL in Met-,2AP(R6), and residues 1,8, MEPLGWQL in Met-,2AP(W6), slow fibrin crosslinking. Conclusion:,Gln14 in both Met-,2AP(R6) and Met-,2AP(W6) is sheltered by the N-terminal 12-residue peptide, which, when cleaved, yields Asn-,2AP, which is rapidly crosslinked to fibrin and maximally protects it from plasmin. The R6 W polymorphism in Met-,2AP does not affect its crosslinking to fibrin, but it does slow cleavage by APCE and reduces the amount of Asn-,2AP available for rapid crosslinking to fibrin. [source] Diagnosis of nonimmediate reactions to ,-lactam antibioticsALLERGY, Issue 11 2004A. Romano Nonimmediate manifestations (i.e. occurring more than 1 h after drug administration), particularly maculopapular and urticarial eruptions, are common during , -lactam treatment. The mechanisms involved in most nonimmediate reactions seem to be heterogeneous and are not yet completely understood. However, clinical and immunohistological studies, as well as analysis of drug-specific T-cell clones obtained from the circulating blood and the skin, suggest that a type-IV (cell-mediated) pathogenic mechanism may be involved in some nonimmediate reactions such as maculopapular or bullous rashes and acute generalized exanthematous pustulosis. In the diagnostic work-up, the patient's history is fundamental; patch testing is useful, together with delayed-reading intradermal testing. The latter appears to be somewhat more sensitive than patch testing, but also less specific. In case of negative allergologic tests, consideration should be given to provocation tests, and the careful administration of the suspect agents. With regard to in vitro tests, the lymphocyte transformation test may contribute to the identification of the responsible drug. Under the aegis of the European Academy of Allergology and Clinical Immunology (EAACI) interest group on drug hypersensitivity and the European Network for Drug Allergy (ENDA), in this review we describe the general guidelines for evaluating subjects with nonimmediate reactions to , -lactams. [source] Polychromatic Light Similar to the Terrestrial Solar Spectrum Without its UV Component Stimulates DNA Synthesis in Human Peripheral Blood Lymphocytes In Vivo and In VitroPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2006Natalya A. Zhevago ABSTRACT Immunosuppressive effects of the minor component of the terrestrial solar spectrum, UV radiation, have been substantiated over the past several years. This raises the question of what influence the dominant part of the solar spectrum,visible and IR light,would have on the human immune system. In the present randomized, placebo-controlled double-blind study a small area of the body surface of volunteers was irradiated with polychromatic light (480,3400 nm), simulating the significant part of the terrestial sunlight irradiance spectrum and its power density. An average 2.5-fold to three-fold increase in spontaneous and phytohemagglutinin-induced DNA synthesis in peripheral blood lymphocytes (Lym) was revealed at 0.5,24 h after irradiation at a therapeutic dose (12 J/cm2) in subjects with low preirradiation levels of both processes. The in vivo findings were echoed in parallel in vitro experiments, when blood drawn from the same subjects was directly irradiated (2.4 J/cm2), or when the irradiated blood was mixed 1:10 with nonirradiated autolo-gous blood to model events in the circulation following transcutaneous blood photomodification. Our data suggest that exposure of the human body to polychromatic visible + IR light may photomodify blood in the dermal vasculature of the irradiated area to lead to an immediate transfer of the light-induced effects to Lym of the entire circulating blood, which can result in modulation of Lym functional state at the systemic level. [source] Oxygenation,Ozonation of Blood During Extracorporeal Circulation: In Vitro Efficiency of a New Gas Exchange DeviceARTIFICIAL ORGANS, Issue 9 2007Velio Bocci Abstract:, We have investigated the performance of a new gas exchange device (GED), named L001, specifically devised for the ozonation of human blood during extracorporeal circulation. This procedure, defined with the acronym "EBOO," means "extracorporeal blood oxygenation,ozonation." The innovative GED is made of microporous, ozone-resistant, polipropylene hollow fibers with an external diameter of 200 µm, a thickness of 50 µm, and a membrane surface area of 0.22 m2. The material is coated with phosphorylcholine on the external side in contact with the circulating blood, while a gas mixture, necessarily composed of medical oxygen and ozone (about 99 and 1%, respectively), flows inside the fibers in opposite direction. The new GED has been tested by using a buffered saline solution containing KI and by varying several parameters, and it has shown to be very versatile and efficient. Its main characteristics are minimal foreign surface contact, high gas transfer, and negligible priming volume. This device appears to be a practical, nontoxic, and rather inexpensive tool for performing ozonation of blood for already defined human diseases. [source] | ||||||||||