Publications by authors named "Joel Graham"

Unlabelled: Interactions between the life-sustaining ventricular assist devices and diagnostic therapies must be carefully considered to decrease the risk of inaccurate diagnostic imaging or pump failure.

Methods: The MVAD(®) pump, currently under investigational use, was tested for interaction with radiotracers in an in vitro flow-loop study. The radiotracers (18)F-sodium fluoride and (18)F-FDG were injected into a closed loop to determine the feasibility of direct imaging of the MVAD(®) pump in a PET scanner.

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New left ventricular assist devices (LVADs) offer both important advantages and potential hazards. VAD development requires better and expeditious ways to identify these advantages and hazards. We validated in an isolated working heart the hemodynamic performance of an intraventricular LVAD and investigated how its outflow cannula interacted with the aortic valve.

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Inadequate research exists regarding testing of a ventricular assist device (VAD) for susceptibility to radiation damage. Specifically, minimal data are available to radiation oncologists prescribing treatment plans for patients with an implanted VAD. As the number of implanted devices increases, patients requiring radiation at tissue sites near or at the device will increase.

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Improved outcomes and quality of life of heart failure patients have been reported with the use of left ventricular assist devices (LVADs). However, little information exists regarding devices in patients undergoing radiation cancer treatment. Two HeartWare Ventricular Assist Device (HVAD) pumps were repeatedly irradiated with high intensity 18 MV x-rays to a dosage range of 64-75 Gy at a rate of 6 Gy/min from a radiation oncology particle accelerator to determine operational stability.

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Despite extensive studies on microbial and enzymatic lignocellulose degradation, relatively few Archaea are known to deconstruct crystalline cellulose. Here we describe a consortium of three hyperthermophilic archaea enriched from a continental geothermal source by growth at 90 °C on crystalline cellulose, representing the first instance of Archaea able to deconstruct lignocellulose optimally above 90 °C. Following metagenomic studies on the consortium, a 90 kDa, multidomain cellulase, annotated as a member of the TIM barrel glycosyl hydrolase superfamily, was characterized.

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Objective: Thromboembolic events have been observed in heart failure (HF) patients supported by long-term mechanical circulatory support (MCS) devices. It has been hypothesized that these adverse events may be the result of platelet activation associated with high rotational speeds common to axial flow pumps. In this study, markers of platelet activation were investigated in HF patients supported by a HeartMate II left ventricular assist device (LVAD).

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Introduction: Platelet adhesion and activation are a significant source of clinical complications. Preventing foreign surface-platelet interaction may improve biocompatibility of implantable medical devices. This study evaluated efficacy of novel technique for electrically modifying surface of conductive biomaterial and attaching blood components to prevent thrombogenesis.

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Synechococcus sp. PCC 7002 is an ideal model cyanobacterium for functional genomics and biotechnological applications through metabolic engineering. A gene expression system that takes advantage of its multiple, endogenous plasmids has been constructed in this cyanobacterium.

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Despite the high potential for oxidative stress stimulated by reduced iron, contemporary iron-depositing hot springs with circum-neutral pH are intensively populated with cyanobacteria. Therefore, studies of the physiology, diversity, and phylogeny of cyanobacteria inhabiting iron-depositing hot springs may provide insights into the contribution of cyanobacteria to iron redox cycling in these environments and new mechanisms of oxidative stress mitigation. In this study the morphology, ultrastructure, physiology, and phylogeny of a novel cyanobacterial taxon, JSC-1, isolated from an iron-depositing hot spring, were determined.

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Synechococcus sp. strain PCC 7002 is a robust, genetically tractable cyanobacterium that produces six different xanthophyll carotenoids (zeaxanthin, cryptoxanthin, myxoxanthophyll (myxol-2'-fucoside), echinenone, 3'-hydroxyechinenone, and synechoxanthin) and tolerates many environmental stresses, including high light intensities. Targeted mutations were introduced to block the branches of the carotenoid biosynthetic pathway leading to specific xanthophylls, and a mutant lacking all xanthophylls was constructed.

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Article Synopsis
  • Pulsatile ventricular assist devices have been important in providing circulatory support, but complications have limited their wider use.
  • The new HeartWare miniature ventricular assist device features a unique design that may reduce cellular trauma and improve patient outcomes, although it hasn't been approved for humans yet.
  • A feasibility study on a calf showed no mechanical failures or health issues, suggesting potential benefits like broader patient availability and lower infection risks, leading to plans for further testing.
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Synechococcus sp. strain PCC 7002 produces a variety of carotenoids, which comprise predominantly dicylic beta-carotene and two dicyclic xanthophylls, zeaxanthin and synechoxanthin. However, this cyanobacterium also produces a monocyclic myxoxanthophyll, which was identified as myxol-2' fucoside.

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In order to enrich the phylogenetic diversity represented in the available sequenced bacterial genomes and as part of an "Assembling the Tree of Life" project, we determined the genome sequence of Thermomicrobium roseum DSM 5159. T. roseum DSM 5159 is a red-pigmented, rod-shaped, Gram-negative extreme thermophile isolated from a hot spring that possesses both an atypical cell wall composition and an unusual cell membrane that is composed entirely of long-chain 1,2-diols.

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The euryhaline, unicellular cyanobacterium Synechococcus sp. strain PCC 7002 produces the dicyclic aromatic carotenoid synechoxanthin (chi,chi-caroten-18,18'-dioic acid) as a major pigment (>15% of total carotenoid) and when grown to stationary phase also accumulates small amounts of renierapurpurin (chi,chi-carotene) (J. E.

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A major aromatic, dicarboxylate carotenoid (>15% of total) was isolated from the euryhaline cyanobacterium Synechococcus sp. PCC 7002. This compound, which was given the common name synechoxanthin (1), has been assigned the structure (all-E) chi,chi-caroten-18,18'-dioic acid by a combination of spectroscopic (UV-vis, FT-IR, (1)H and (13)C NMR, LC-MS) and chemical methods.

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Sustained myocardial recovery and reversal of heart failure has been reported with the use of left ventricular assist devices (LVADs). However, clinical predictors of sustained recovery have not been clearly defined, and little information exists regarding exercise improvement in LVAD patients. Therefore, we sought to determine whether peripheral oxygen delivery and utilization were improved with LVAD support.

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Ongoing work has led to the identification of most of the biochemical steps in carotenoid biosynthesis in chlorophototrophic bacteria. In carotenogenesis, a relatively small number of modifications leads to a great diversity of carotenoid structures. This review examines the individual steps in the pathway, discusses how each contributes to structural diversity among carotenoids, and summarizes recent progress in elucidating the biosynthetic pathways for carotenoids in chlorophototrophs.

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The use of cardiopulmonary bypass (CPB) is associated with the development of a significant systemic inflammatory response syndrome (SIRS) which can affect patient outcomes. Multiple pathways are involved in initiating and maintaining SIRS. We studied whether a single dose of steroids (dexamethasone) after the induction of anesthesia could blunt the SIRS from CPB.

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Results for Destination Therapy (DT) continue to improve with advanced technology, better patient selection, and experienced clinical management. Quality of life for these patients is an important component of the overall success of DT, and traveling is becoming more common. We reviewed our experience with long-distance travel in our DT population.

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Human physiologic responses to pulsatile left ventricular assist devices (LVADs) are well understood; responses to the newer continuous flow pumps are not. Therefore, we evaluated the long-term effects of continuous flow LVAD support on fibrinolytic activation. Twelve recipients of an axial flow LVAD as destination therapy were assessed for fibrinolytic activation at 1, 3, 6, 9, and 12 months postimplantation.

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A fourth and large family of lycopene cyclases was identified in photosynthetic prokaryotes. The first member of this family, encoded by the cruA gene of the green sulfur bacterium Chlorobium tepidum, was identified in a complementation assay with a lycopene-producing strain of Escherichia coli. Orthologs of cruA are found in all available green sulfur bacterial genomes and in all cyanobacterial genomes that lack genes encoding CrtL- or CrtY-type lycopene cyclases.

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Transposition of the Ty1 element of the yeast Saccharomyces cerevisiae is temperature sensitive. We have identified a null allele of the silent information regulator gene SIR4 as a host mutant that allows for transposition at high temperature. We show that the apparent increase in transposition activity in sir4 mutant strains at high temperature is dependent on the RAD52 gene and is thus likely resulting from an increase in Ty1 cDNA recombination, rather than in IN-mediated integration.

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