beta-Adrenergic receptor stimulated Ncx1 upregulation is mediated via a CaMKII/AP-1 signaling pathway in adult cardiomyocytes.

The Na(+)-Ca(2+) exchanger gene (Ncx1) is upregulated in hypertrophy and is often found elevated in end-stage heart failure. Studies have shown that the change in its expression contributes to contractile dysfunction. beta-Adrenergic receptor (beta-AR) signaling plays an important role in the regulation of calcium homeostasis in the cardiomyocyte, but chronic activation in periods of cardiac stress contributes to heart failure by mechanisms which include Ncx1 upregulation. Here, using a Ca(2+)/calmodulin-dependent protein kinase II (CaMKIIdelta(c)) null mouse, we demonstrate that beta-AR-stimulated Ncx1 upregulation is dependent on CaMKII. beta-AR-stimulated Ncx1 expression is mediated by activator protein 1 (AP-1) factors and is independent of cAMP-response element-binding protein (CREB) activation. The MAP kinases (ERK1/2, JNK and p38) are not required for AP-1 factor activation. Chromatin immunoprecipitation demonstrates that beta-AR stimulation activates the ordered recruitment of JunB homodimers, which then are replaced by c-Jun homodimers binding to the proximal AP-1 elements of the endogenous Ncx1 promoter. In conclusion, this work has provided insight into the intracellular signaling pathways and transcription factors regulating Ncx1 gene expression in a chronically beta-AR-stimulated heart.

Acute mucosal pathogenesis of feline immunodeficiency virus is independent of viral dose in vaginally infected cats.

BACKGROUND: The mucosal pathogenesis of HIV has been shown to be an important feature of infection and disease progression. HIV-1 infection causes depletion of intestinal lamina propria CD4+ T cells (LPL), therefore, intestinal CD4+ T cell preservation may be a useful correlate of protection in evaluating vaccine candidates. Vaccine studies employing the cat/FIV and macaque/SIV models frequently use high doses of parenterally administered challenge virus to ensure high plasma viremia in control animals. However, it is unclear if loss of mucosal T cells would occur regardless of initial viral inoculum dose. The objective of this study was to determine the acute effect of viral dose on mucosal leukocytes and associated innate and adaptive immune responses. RESULTS: Cats were vaginally inoculated with a high, middle or low dose of cell-associated and cell-free FIV. PBMC, serum and plasma were assessed every two weeks with tissues assessed eight weeks following infection. We found that irrespective of mucosally administered viral dose, FIV infection was induced in all cats. However, viremia was present in only half of the cats, and viral dose was unrelated to the development of viremia. Importantly, regardless of viral dose, all cats experienced significant losses of intestinal CD4+ LPL and CD8+ intraepithelial lymphocytes (IEL). Innate immune responses by CD56+CD3- NK cells correlated with aviremia and apparent occult infection but did not protect mucosal T cells. CD4+ and CD8+ T cells in viremic cats were more likely to produce cytokines in response to Gag stimulation, whereas aviremic cats T cells tended to produce cytokines in response to Env stimulation. However, while cell-mediated immune responses in aviremic cats may have helped reduce viral replication, they could not be correlated to the levels of viremia. Robust production of anti-FIV antibodies was positively correlated with the magnitude of viremia. CONCLUSIONS: Our results indicate that mucosal immune pathogenesis could be used as a rapid indicator of vaccine success or failure when combined with a physiologically relevant low dose mucosal challenge. We also show that innate immune responses may play an important role in controlling viral replication following acute mucosal infection, which has not been previously identified.

In vivo depletion of CD4(+)CD25(hi) regulatory T cells is associated with improved antiviral responses in cats chronically infected with feline immunodeficiency virus.

Regulatory T (Treg) cells are activated and suppress immune responses during infection, and are characterized as CD4(+)CD25(hi)FOXP3(+). Ex vivo studies demonstrate that Treg cells potentially suppress anti-HIV-1 T cell responses. Lentivirus-induced CD4(+)CD25(hi) Treg cells were first described in feline immunodeficiency virus (FIV)-infected cats. In the present study we demonstrate that anti-feline CD25 monoclonal antibody (mAb) therapy depletes Treg cells in FIV-infected cats for 4 weeks and does not exacerbate viral replication or proinflammatory cytokine production. Significant FIV-specific immune responses are revealed in Treg cell-depleted cats. These anti-FIV effector cells exist prior to Treg cell depletion and are not expanded while Treg cells are depleted. Importantly, cats receiving the Treg cell-depleting mAb are able to produce a robust humoral response to new antigen. We propose that short-term in vivo Treg cell depletion during chronic HIV-1 infection could provide a window of opportunity for therapeutic vaccination in individuals with controlled viral replication.

The clinical response to brain death: a policy proposal.

The ethical and scientific literature reflects a certain amount of controversy and confusion surrounding the concept of death by neurological criteria, or brain death. The issues surrounding brain death occur with limited frequency for those working in acute critical care settings. Even so, the literature and our own experiences evidence the discomfort of caregivers and policymakers when dealing with brain-dead patients and their family and loved ones. One particular area in which there seems to be significant diversity of opinion is what should occur when death by neurological criteria is pronounced. At some hospitals, when the patient is pronounced dead by neurological criteria, the support equipment is removed from the body immediately and the body is prepared for visitation by family or is transported to the morgue. In other hospitals, support equipment is maintained for a certain limited period to allow the family to be present when the equipment is ultimately removed. In general, however, it appears that institutional guidelines and policy are vague, at best, or often silent about the issue of when, how, and, to some extent, who decides what is done with the body. This policy paper discusses the confusion of care providers as well as lay persons related to the general concepts of death by neurological criteria. In addition, alternative approaches to the withdrawal of support equipment are examined. This article may also allow nursing administrators to better understand the importance of establishing specific clinical guidelines for their staff related to patients declared dead by neurological criteria. Our conclusion is that a universal policy should be adopted whereby all institutions develop the same guidelines concerning when and how treatment modalities should be withdrawn on their brain-dead patients. Such policy guidelines may not extinguish the misconceptions, misunderstandings, and discomforts that are present with a diagnosis of brain death, but it would certainly allow for more consistent actions on the part of the caregivers. Consistency would substantially benefit caregivers, families, and society alike.

Comparing ethics education in medicine and law: combining the best of both worlds.

This article compares various models of ethics education and how these models are employed by both medical schools and law schools. The authors suggest ways in which each profession can enhance their ethical teaching and argue that ethics education in both medicine and law should combine the best elements of each education model, thereby producing graduates who are more knowledgeable and appreciative of ethical issues in practice.