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Biomedical subjects

T J Gardner

Publications and source records attributed to T J Gardner.

At least 19 recordsLinked to original sources
PubMed2000

Blocking free radical production via adenoviral gene transfer decreases cardiac ischemia-reperfusion injury.

Periods of cardiac ischemia followed by reperfusion can lead to either transient loss of function (stunning) or permanent functional loss stemming from infarction, depending upon the length of the ischemic period. In either case the primary mediator of the injury may by oxygen-derived free radicals generated upon the reestablishment of blood flow. The heart's primary defense against peroxide, glutathione peroxidase, is depleted during ischemia. Thus, the ischemic myocardium might derive significant protection from increased levels of the enzyme, catalase, which can remove hydrogen peroxide in a redox-independent manner. To test these assertions, we studied the ability of adenoviral gene transfer to increase intracellular antioxidant activity via catalase expression. What we observed was that increasing catalase activity in the heart was sufficient to prevent the stunning associated with 15 min of ischemia followed by reperfusion.

Adenoviridae↗
PubMed2000

Cardiothoracic intensive care: operation and administration.

The cardiothoracic surgery intensive care unit (CTICU) has evolved as a separate entity from the general surgical intensive care unit as management for cardiac surgery patients has become streamlined and algorithm driven. Critical care is best managed when the service is designed for a homogeneous population with a circumscribed set of medical and surgical issues. The repetition involved with the subspecialty care allows health care providers such as primary care nurses, nurse practitioners, physician assistants, and other ancillary services to become appropriately focused on issues pertinent to this population. The goals of the CTICU include the attainment of rapid and safe recovery from surgery and anesthesia despite decreasing resources, increasing patient age and comorbidity, and increasing complexity of the operative procedure. The coordinated and systematic approach to the postoperative cardiac surgery patient under the direction of a staff physician offers the most effective opportunity to achieve these expectations at this time. The traditional model of staffing by a physician with responsibilities that conflict temporally with the immediacy often needed for the postoperative care of cardiac patients may expose patients to unnecessary risks. A responsible physician should be available in the CTICU, especially during the immediate postoperative period when physical assessment and direct hands-on involvement are essential. In an era when the operative team (ie, cardiac surgeon and cardiac anesthesiologist) must return to the surgical suite soon after the patient arrives in the intensive care unit, the presence of a physician dedicated to postoperative medical and surgical management becomes mandatory. According to the Joint Commission on Accreditation of Healthcare Organizations, "Each special care unit is properly directed and staffed according to the nature of the special patient care needs anticipated and scope of services provided." The assignment of staff is designed to match experience with patient acuity.

Cardiac Surgical Procedures↗
PubMed1998

Recombinant adenovirus-mediated cardiac gene transfer of superoxide dismutase and catalase attenuates postischemic contractile dysfunction.

BACKGROUND: Coronary revascularization entails obligatory myocardial ischemia followed by reperfusion with occasional resultant postischemic contractile dysfunction, a state associated with significant morbidity and mortality. This injury is attributed in part to oxygen free radicals and has been partially ameliorated with exogenous antioxidants, a strategy limited by agent instability, low titer, and inadequate cardiomyocyte uptake. Cardiac gene transfer with antioxidant encoding vectors may significantly enhance intracellular free radical scavenger activity. METHODS AND RESULTS: C57/BL6 neonatal mice (age, 2 days; n = 131) underwent intrapericardial delivery of recombinant adenoviruses encoding superoxide dismutase (SOD) and catalase (Cat) (n = 76) or beta-galactosidase (LacZ) as a control (n = 55). After 3 days, hearts were explanted, and SOD and Cat transgene expression was detected by Western blot analysis. Spectrophotometric enzyme assays demonstrated enhanced SOD activity 1.6-fold (P < 0.0001) and Cat 3.6-fold (P < 0.00001) in experimental versus LacZ hearts. Isolated perfused hearts were subjected to 5 minutes of warm ischemia, and at 5, 10, and 15 minutes after initiation of reperfusion, LacZ controls lost 24%, 33%, and 41% of peak systolic apicobasal force, respectively, whereas experimental hearts lost 5%, 12%, and 20% (P < 0.001, each time point). In controls, rate of force generation diminished 8%, 17%, and 35%; in experimental hearts, it increased 1% at 5 minutes and decreased 5% and 15% and 10 and 15 minutes (P < 0.01, P < 0.05, P < 0.05). LacZ hearts exhibited dysfunction similar to hearts from uninjected animals (P = NS, each time point). CONCLUSIONS: Adenovirus-mediated cardiac gene transfer and expression of SOD and Cat augment antioxidant enzyme activity and minimize contractile dysfunction after ischemic reperfusion in the isolated perfused neonatal mouse heart.

Adenoviridae↗