2,217 research outputs found

    Stability of Glutamate-Aspartate Cardioplegia Additive Solution in Polyolefin IV Bags

    Get PDF
    Objective: Glutamate-aspartate cardioplegia additive solution (GACAS) is used to enhance myocardial preservation and left ventricular function during some cardiac surgeries. This study was designed to evaluate the stability of compounded GACAS stored in sterile polyolefin intravenous (IV) bags. The goal is to extend the default USP beyond-use date (BUD) and reduce unnecessary inventory waste. Methods: GACAS was compounded and packaged in sterile polyolefin 250 mL IV bags. The concentration was 232 mM for each amino acid. The samples were stored under refrigeration (2°C-8°C) and analyzed at 0, 1, and 2 months. At each time point, the samples were evaluated by pH measurement and visual inspection for color, clarity, and particulates. The samples were also analyzed by high-performance liquid chromatography (HPLC) for potency and degradation products. Due to the lack of ultraviolet (UV) chromophores of glutamate and aspartate, the samples were derivatized by ortho-phthalaldehyde prior to HPLC analysis. Results: The time zero samples of GACAS passed the physical, chemical, and microbiological tests. Over 2 months of storage, there was no significant change in pH or visual appearance for any of the stability samples. The HPLC results also indicated that the samples retained 101% to 103% of the label claim strengths for both amino acids. Conclusion: The physical and chemical stability of extemporaneously prepared GACAS has been confirmed for up to 2 months in polyolefin IV bags stored under refrigeration. With proper sterile compounding practice and microbiology testing, the BUD of this product can be extended to 2 months

    Fallout from U.S. atmospheric nuclear tests in New Mexico and Nevada (1945-1962)

    Full text link
    One hundred and one atmospheric nuclear weapon tests were conducted between 1945 and 1962 in the United States, resulting in widespread dispersion of radioactive fallout, and leading to environmental contamination and population exposures. Accurate assessment of the extent of fallout from nuclear weapon tests has been challenging in the United States and elsewhere, due to limited monitoring and data accessibility. Here we address this deficit by combining U.S. government data, high-resolution reanalyzed historical weather fields, and atmospheric transport modeling to reconstruct radionuclide deposition across the contiguous United States, with 10-kilometer spatial and one-hour temporal resolution for five days following detonation, from all 94 atmospheric tests detonated in New Mexico and Nevada with fission yields sufficient to generate mushroom clouds. Our analysis also includes deposition estimates for 10 days following the detonation of Trinity, the first ever nuclear weapon test, on July 16, 1945. We identify locations where radionuclide deposition significantly exceeded levels in areas covered by the U.S. Radiation Exposure Compensation Act (RECA). These findings include deposition in all 48 contiguous U.S. states. They provide an opportunity for re-evaluating the public health and environmental implications from atmospheric nuclear testing. Finally, our findings also speak to debates about marking the beginning of the Anthropocene with nuclear weapons fallout. Our deposition estimates indicate that direct fallout from Trinity, a plutonium device, reached Crawford Lake in Canada, the proposed "golden spike" site marking the beginning of the Anthropocene epoch, starting on July 20, 1945.Comment: 19 pages, 4 figures, 1 supplementary table, 3 supplementary figure

    Evidence for cooperative interactions between the two motor domains of cytoplasmic dynein

    Get PDF
    AbstractCytoplasmic dynein is a force-transducing ATPase that powers the movement of cellular cargoes along microtubules. Two identical heavy chain polypeptides (> 500 kDa) of the cytoplasmic dynein complex contain motor domains that possess the ATPase and microtubule-binding activities required for force production [1]. It is of great interest to determine whether both heavy chains (DHCs) in the dynein complex are required for progression of the mechanochemical cycle and motility, as observed for other dimeric motors. We have used transgenic constructs to investigate cooperative interactions between the two motor domains of the Drosophila cytoplasmic dynein complex. We show that 138 kDa and 180 kDa amino-terminal fragments of DHC can assemble with full-length DHC to form heterodimeric complexes containing only a single motor domain. The single-headed dynein complexes can bind and hydrolyze ATP, yet do not show the ATP-induced detachment from microtubules that is characteristic of wild-type homodimeric dynein. These results suggest that cooperative interactions between the monomeric units of the dimer are required for efficient ATP-induced detachment of dynein and unidirectional movement along the microtubule

    Why are Kinesin-2 KIF3AB and KIF3AC so Processive?

    Get PDF
    • 

    corecore