Six-month angiographic follow-up of the PAS-Port II clinical trial

BACKGROUND: The PAS-Port device (Cardica, Redwood City, CA) allows the rapid deployment of a clampless proximal anastomosis between a vein graft and the aorta. METHODS: Fifty-four patients awaiting elective coronary artery bypass graft surgery were enrolled. Outcome variables were intraoperative device performance, early and 6- month angiographic graft patency, and 12-month clinical follow-up. RESULTS: Sixty-three PAS-Port devices were deployed in 54 patients. Two deployments were unsuccessful. There were no reoperations for bleeding. Two patients died of causes unrelated to the device. Patency evaluation at discharge was performed by angiogram on 49 implants and computed tomography in 2 implants (86% follow-up). At discharge, all evaluated grafts were patent (100%) and rated Fitzgibbon A. At 6-month follow-up, there was no additional mortality; 47 implants (88% follow-up) were evaluated by angiography (Fitzgibbon O [n = 1], Fitzgibbon B [n = 1], and Fitzgibbon A [n = 45]) and 5 by computed tomography. All grafts but 1 were patent (98.1%). At 12 months, 2 additional patients died of causes unrelated to the PAS-Port implant. Forty-six of 50 alive patients (95.8%) were followed up without any reports of device-related major adverse cardiac events. CONCLUSIONS: Discharge (100%) and 6-month patency (98%) are excellent; patency and 12 months' clinical follow-up compares favorably with data from historical hand-sewn controls. The PAS-Port system safely allows the clampless creation of a proximal anastomosis.

Intracellular Ca(2+) operates a switch between repair and lysis of streptolysin O-perforated cells

Pore-forming (poly)peptides originating from invading pathogens cause plasma membrane damage in target cells, with consequences as diverse as proliferation or cell death. However, the factors that define the outcome remain unknown. We show that in cells maintaining an intracellular Ca(2+) concentration [Ca(2+)](i) below a critical threshold of 10 microM, repair mechanisms seal off 'hot spots' of Ca(2+) entry and shed them in the form of microparticles, leading to [Ca(2+)](i) reduction and cell recovery. Cells that are capable of preventing an elevation of [Ca(2+)](i) above the critical concentration, yet are unable to complete plasma membrane repair, enter a prolonged phase of [Ca(2+)](i) oscillations, accompanied by a continuous shedding of microparticles. When [Ca(2+)](i) exceeds the critical concentration, an irreversible formation of ceramide platforms within the plasma membrane and their internalisation drives the dying cells beyond the 'point of no return'. These findings show that the extent of [Ca(2+)](i) elevation determines the fate of targeted cells and establishes how different Ca(2+)-dependent mechanisms facilitate either cell survival or death.

Short-term response of the Ca cycle of a montane forest in Ecuador to low experimental CaCl 2 additions

The tropical montane forests of the E Andean cordillera in Ecuador receive episodic Sahara-dust inputs particularly increasing Ca deposition. We added CaCl2 to isolate the effect of Ca deposition by Sahara dust to tropical montane forest from the simultaneously occurring pH effect. We examined components of the Ca cycle at four control plots and four plots with added Ca (2 × 5 kg ha–1 Ca annually as CaCl2) in a random arrangement. Between August 2007 and December 2009 (four applications of Ca), we determined Ca concentrations and fluxes in litter leachate, mineral soil solution (0.15 and 0.30 m depths), throughfall, and fine litterfall and Al concentrations and speciation in soil solutions. After 1 y of Ca addition, we assessed fine-root biomass, leaf area, and tree growth. Only < 3% of the applied Ca leached below the acid organic layer (pH 3.5–4.8). The added CaCl2 did not change electrical conductivity in the root zone after 2 y. In the second year of fertilization, Ca retention in the canopy of the Ca treatment tended to decrease relative to the control. After 2 y, 21% of the applied Ca was recycled to soil with throughfall and litterfall. One year after the first Ca addition, fine-root biomass had decreased significantly. Decreasing fine-root biomass might be attributed to a direct or an indirect beneficial effect of Ca on the soil decomposer community. Because of almost complete association of Al with dissolved organic matter and high free Ca2+ : Al3+ activity ratios in solution of all plots, Al toxicity was unlikely. We conclude that the added Ca was retained in the system and had beneficial effects on some plants.