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O2 Carriers (o2 + carrier)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Improved Outcomes in Islet Isolation and Transplantation by the Use of a Novel Hemoglobin-based O2 Carrier

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2006
J. G. Avila
During isolation, islets are exposed to warm ischemia. In this study, intraductal administration of oxygenated polymerized, stroma-free hemoglobin-pyridoxalated (Poly SFH-P) was performed to improve O2 delivery. Rat pancreata subjected to 30-min warm ischemia were perfused intraductally with collagenase in oxygenated Poly SFH-P/RPMI or RPMI (control). PO2 was increased by Poly SFH-P (381.7 ± 35.3 mmHg vs. 202.3 ± 28.2, p = 0.01) and pH maintained within physiological range (7.4,7.2 vs. 7.1,6.6, p = 0.009). Islet viability (77%± 4.6 vs. 63%± 4.7, p = 0.04) was improved and apoptosis lower with Poly SFH-P (caspase-3: 34,714 ± 2167 vs. 45,985 ± 1382, respectively, p = 0.01). Poly SFH-P improved islet responsiveness to glucose as determined by increased intracellular Ca2+ levels and improved insulin secretion (SI 5.4 ± 0.1 vs. 3.1 ± 0.2, p = 0.03). Mitochondrial integrity was improved in Poly SFH-P-treated islets, which showed higher percentage change in membrane potential after glucose stimulation (14.7%± 1.8 vs. 9.8 ± 1.4, respectively, p < 0.05). O2 delivery by Poly SFH-P did not increase oxidative stress (GSH 7.1 ± 2.9 nm/mg protein for Poly SFH-P vs. 6.8 ± 2.4 control, p = 0.9) or oxidative injury (MDA 1.8 ± 0.9 nmol/mg protein vs. 6.2 ± 2.4, p = 0.19). Time to reach normoglycemia in transplanted diabetic nude mice was shorter (1.8 ± 0.4 vs. 7 ± 2.5 days, p = 0.02), and glucose tolerance improved in the Poly SFH-P group (AUC 8106 ± 590 vs. 10,863 ± 946, p = 0.03). Oxygenated Poly SFH-P improves islet isolation and transplantation outcomes by preserving mitochondrial integrity. [source]

HemoCD as an Artificial Oxygen Carrier: Oxygen Binding and Autoxidation

ARTIFICIAL ORGANS, Issue 2 2009
Koji Kano
Abstract Despite many attempts to construct completely artificial systems for carrying oxygen (O2) in aqueous solution, no successful example had been reported until quite recently except for picket fence porphinatoiron(II) embedded in liposomal membrane. We newly prepared a 1:1 complex (hemoCD) of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphinatoiron(II) (Fe[II]TPPS) and a per- O -methylated ,-cyclodextrin dimer having a pyridine linker (Py3CD). HemoCD binds O2 reversibly in aqueous solution. The oxygen affinity corresponding to the partial O2 pressure, at which half of the hemoCD molecules are oxygenated, was 16.9 torr in phosphate buffer at pH 7.0 and 25°C. Oxy-hemoCD was gradually autoxidized (t1/2 = 30.1 h) due to nucleophilic attack of a water molecule to the O2,Fe bond. Encapsulation of the iron center of Fe(II)TPPS by two cyclodextrin truncated cones is essential for binding of O2 to the ferrous center of the porphyrin. This manuscript reports the basic characteristics of hemoCD and the possible future utility of a totally artificial O2 carrier. [source]

Overview of artificial O2 carriers

ISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2006
A. Pape
First page of article [source]

Near-stoichiometric O2 binding on metal centers in Co(salen) nanoparticles

AICHE JOURNAL, Issue 4 2009
Chad Johnson
Abstract Co(salen) [cobaltous bis(salicylaldehyde)ethylenediamine] complexes are well-known O2 carriers in solution. In the solid phase, these complexes exhibit some O2 binding but detailed studies have been complicated because few of the known polymorphs of Co(salen) actually bind O2. The O2 binding results for nanoparticulate Co(salen) are presented in this study. Rod-shaped Co(salen) nanoparticles, roughly 100 nm in diameter, were recrystallized by spraying a methylene chloride solution of commercially obtained Co(salen) into supercritical carbon dioxide. Temperature-programmed desorption, thermogravimetric analysis, and a Rubotherm magnetic suspension balance measurements reveal a reversible O2 uptake of ,1.51 mmol/(g nanoparticles) at 25°C, consistent with a binding stoichiometry involving a bridging peroxo unit between two Co centers. In contrast, no measurable O2 uptake was observed with the commercial Co(salen). These results clearly show the potential for bottom-up design of nanoparticulate metal complexes for enhanced O2 storage and other applications. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]