An Unusual Cause of Hypoxia: Ventricular Septal Defect, Pulmonary Artery Atresia, and Major Aortopulmonary Collaterals Diagnosed in the Adult Cardiac Catheterization Lab.

The association of pulmonary atresia, ventricular septal defect (VSD) and major aortopulmonary collaterals (MAPCA) is an extreme form of tetralogy of Fallot (TOF). It carries a high mortality risk if not intervened on during infancy with only 20% of unoperated patients surviving into adulthood. We present the case of a 40-year-old man who presented for evaluation prior to retinal surgery and was found to have hypoxia and a loud murmur. Cardiac catheterization was performed in the general catheterization laboratory, demonstrating a membranous VSD, pulmonary atresia, and MAPCA. We highlight the challenges and limitations that an adult interventional cardiologist may have when encountering these patients.

Surface-enhanced Raman spectroscopy competitive binding biosensor development utilizing surface modification of silver nanocubes and a citrulline aptamer.

A point-of-care (PoC) device with the ability to detect biomarkers at low concentrations in bodily fluids would have an enormous potential for medical diagnostics outside the central laboratory. One method to monitor analytes at low concentrations is by using surface-enhanced Raman spectroscopy (SERS). In this preliminary study toward using SERS for PoC biosensing, the surface of colloidal silver (Ag) nanocubes has been modified to test the feasibility of a competitive binding SERS assay utilizing aptamers against citrulline. Specifically, Ag nanocubes were functionalized with mercaptobenzoic acid, as well as a heterobifunctional polyethylene glycol linker that forms an amide bond with the amino acid citrulline. After the functionalization, the nanocubes were characterized by zeta-potential, transmission electron microscopy images, ultraviolet/visible spectroscopy, and by SERS. The citrulline aptamers were developed and tested using backscattering interferometry. The data show that our surface modification method does work and that the functionalized nanoparticles can be detected using SERS down to a 24.5 picomolar level. Last, we used microscale thermophoresis to show that the aptamers bind to citrulline with at least a 50 times stronger affinity than other amino acids. Download PDF SAVE FOR LATER

Multimodal optical coherence tomography and fluorescence lifetime imaging with interleaved excitation sources for simultaneous endogenous and exogenous fluorescence.

Multimodal imaging probes a variety of tissue properties in a single image acquisition by merging complimentary imaging technologies. Exploiting synergies amongst the data, algorithms can be developed that lead to better tissue characterization than could be accomplished by the constituent imaging modalities taken alone. The combination of optical coherence tomography (OCT) with fluorescence lifetime imaging microscopy (FLIM) provides access to detailed tissue morphology and local biochemistry. The optical system described here merges 1310 nm swept-source OCT with time-domain FLIM having excitation at 355 and 532 nm. The pulses from 355 and 532 nm lasers have been interleaved to enable simultaneous acquisition of endogenous and exogenous fluorescence signals, respectively. The multimodal imaging system was validated using tissue phantoms. Nonspecific tagging with Alexa Flour 532 in a Watanbe rabbit aorta and active tagging of the LOX-1 receptor in human coronary artery, demonstrate the capacity of the system for simultaneous acquisition of OCT, endogenous FLIM, and exogenous FLIM in tissues.

Use of a micro- to nanochannel for the characterization of surface-enhanced Raman spectroscopy signals from unique functionalized nanoparticles.

A micro- to nanochannel nanoparticle aggregating device that does not require any input energy to organize the particles to a specific location, i.e., no pumps, plugs, heat, or magnets, has been designed and used to characterize the surface-enhanced Raman spectroscopy (SERS) signal from four unique functionalized nanoparticles (gold, silver-gold nanocages, silver nanocubes, and silica-gold nanoshells). The SERS signal was assessed in terms of the peak signal strength from the four different Raman reporter functionalized nanoparticles to determine which nanoparticle had better utility in the channel to provide the most robust platform for a future biological analyte detection device. The innovation used to fabricate the micro- to nanochannel device is described; the TEM images of the nanoparticles are shown; the absorption data for the nanoparticles are given; and the spectral data for the Raman reporter, mercaptobenzoic acid (MBA), are depicted. In the micro- to nanochannel described in this work, 5 µl of 22.3 µM MBA functionalized silver nanocubes were determined to have the strongest SERS enhancement.

Intimacy and a deadly feud: the interplay of autophagy and apoptosis mediated by amino acids.

Autophagy (i.e., "self-eating") and apoptosis (i.e., type I programmed cell death) are essential and intimately involved in molecular, cellular, and whole-body homeostasis in humans and animals. Autophagy has been categorized as a mechanism of intracellular degradation, recycling, defense, and survival. To date, three types of autophagy have been identified: macroautophagy, microautophagy, and chaperone-mediated autophagy. Recent discoveries strongly suggest that macroautophagy also modulates type II programmed cell death under specific circumstances. Autophagy and apoptosis are fundamentally distinct processes, but are interconnected by common stress initiators and intermediate regulators. During the past two decades, the role of amino acid metabolism and signaling in the regulation of apoptosis and autophagy has been intensively studied. In this review, we summarize recent advances in our understanding of the molecular mechanisms that regulate both autophagy and apoptosis in the context of amino acid signaling.

Simultaneous morphological and biochemical endogenous optical imaging of atherosclerosis.

AIMS: The aim of this study was to validate novel imaging technology for simultaneous morphological and biochemical endogenous optical imaging of coronary atherosclerotic plaque. METHODS AND RESULTS: Optical coherence tomography (OCT) generates high-resolution 3D images of plaque morphology and endogenous fluorescence lifetime imaging microscopy (FLIM) characterizes biochemical composition. Both imaging modalities rely on plaque's intrinsic optical characteristics, making contrast agents unnecessary. A multimodal OCT/FLIM system was utilized to generate luminal biochemical maps superimposed on high-resolution (7 µm axial and 13 µm lateral) structural volumetric images. Forty-seven fresh postmortem human coronary segments were imaged: pathological intimal thickening (PIT, n = 26), fibroatheroma (FA, n = 12), thin-cap FA (TCFA, n = 2), and fibrocalcific plaque (CA, n = 7), determined by histopathology. Multimodal images were evaluated, and each plaque identified as PIT, FA, TCFA, or CA based on expert OCT readers, and as having high-lipid (HL), high-collagen (HC), or low-collagen/low-lipid (LCL) luminal composition based on linear discriminant analysis of FLIM. Of 47 plaques, 89.4% (42/47) of the plaques were correctly identified based on OCT/FLIM evaluation using tissue histopathology and immunohistochemistry as the gold standard. Four of the misclassifications corresponded to confusing PIT with HL luminal composition for FA with HL cap. The other corresponded to confusing FA with a HC cap for FA with an LCL cap. CONCLUSION: We have demonstrated the feasibility of accurate simultaneous OCT/FLIM morphological and biochemical characterization of coronary plaques at spatial resolutions and acquisition speeds compatible with catheter-based intravascular imaging. The success of this pilot study sets up future development of a multimodal intravascular imaging system that will enable studies that could help improve our understanding of plaque pathogenesis.

Delivery of negatively charged liposomes into the atherosclerotic plaque of apolipoprotein E-deficient mouse aortic tissue.

Liposomes have been used to diagnose and treat cancer and, to a lesser extent, cardiovascular disease. We previously showed the uptake of anionic liposomes into the atheromas of Watanabe heritable hyperlipidemic rabbits within lipid pools. However, the cellular distribution of anionic liposomes in atherosclerotic plaque remains undescribed. In addition, how anionic liposomes are absorbed into atherosclerotic plaque is unclear. We investigated the uptake and distribution of anionic liposomes in atherosclerotic plaque in aortic tissues from apolipoprotein E-deficient (ApoE(-/-)) mice. To facilitate the tracking of liposomes, we used liposomes containing fluorescently labeled non-silencing small interfering RNA. Confocal microscopy analysis showed the uptake of anionic liposomes into atherosclerotic plaque and colocalization with macrophages. Transmission electron microscopy analysis revealed anionic liposomal accumulation in macrophages. To investigate how anionic liposomes cross the local endothelial barrier, we examined the role of clathrin-mediated endocytosis in human coronary artery endothelial cells (HCAECs) treated with or without the inflammatory cytokine tumor necrosis factor (TNF)-α. Pretreatment with amantadine, an inhibitor of clathrin-mediated endocytosis, significantly decreased liposomal uptake in HCAECs treated with or without TNF-α by 77% and 46%, respectively. Immunoblot analysis showed that endogenous clathrin expression was significantly increased in HCAECs stimulated with TNF-α but was inhibited by amantadine. These studies indicated that clathrin-mediated endocytosis is partly responsible for the uptake of liposomes by endothelial cells. Our results suggest that anionic liposomes target macrophage-rich areas of vulnerable plaque in ApoE(-)(/)(-) mice; this finding may lead to the development of novel diagnostic and therapeutic strategies for treating vulnerable plaque in humans.

Electronegative low-density lipoprotein increases C-reactive protein expression in vascular endothelial cells through the LOX-1 receptor.

OBJECTIVES: Increased plasma C-reactive protein (CRP) levels are associated with the occurrence and severity of acute coronary syndrome. We investigated whether CRP can be generated in vascular endothelial cells (ECs) after exposure to the most electronegative subfraction of low-density lipoprotein (LDL), L5, which is atherogenic to ECs. Because L5 and CRP are both ligands for the lectin-like oxidized LDL receptor-1 (LOX-1), we also examined the role of LOX-1. METHODS AND RESULTS: Plasma LDL samples isolated from asymptomatic hypercholesterolemic (LDL cholesterol [LDL-C] levels, 154.6±20 mg/dL; n = 7) patients and normocholesterolemic (LDL-C levels, 86.1±21 mg/dL; P<0.001; n = 7) control individuals were chromatographically resolved into 5 subfractions, L1-L5. The L5 percentage (L5%) and the plasma L5 concentration ([L5]  =  L5% × LDL-C) in the patient and control groups were 8.1±2% vs. 2.3±1% (P<0.001) and 12.6±4 mg/dL vs. 1.9±1 mg/dL (P<0.001), respectively. In hypercholesterolemic patients treated with atorvastatin for 6 months (10 mg/day), [L5] decreased from 12.6±4 mg/dL to 4.5±1.1 mg/dL (P = 0.011; n = 5), whereas both [L5] and L5% returned to baseline levels in 2 noncompliant patients 3 months after discontinuation. In cultured human aortic ECs (HAECs), L5 upregulated CRP expression in a dose- and time-dependent manner up to 2.5-fold (P<0.01), whereas the least electronegative subfraction, L1, had no effect. DiI-labeled L1, internalized through the LDL receptor, became visible inside HAECs within 30 seconds. In contrast, DiI-labeled L5, internalized through LOX-1, became apparent after 5 minutes. L5-induced CRP expression manifested at 30 minutes and was attenuated by neutralizing LOX-1. After 30 minutes, L5 but not L1 induced reactive oxygen species (ROS) production. Both L5-induced ROS and CRP production were attenuated by ROS inhibitor N-acetyl cysteine. CONCLUSIONS: Our results suggest that CRP, L5, and LOX-1 form a cyclic mechanism in atherogenesis and that reducing plasma L5 levels with atorvastatin disrupts the vascular toxicity of L5.

Delivery of negatively charged liposomes into the atheromas of Watanabe heritable hyperlipidemic rabbits.

Liposomes have been used as imaging and therapeutic agents in various tissues but only infrequently in the cardiovascular system. We prepared a liposome to target atheromas in a Watanabe heritable hyperlipidemic (WHHL) rabbit model. Liposomes labeled with rhodamine and nanogold were injected intra-arterially into the descending thoracic aortas of WHHL rabbits. The arterial segments of interest were perfusion-fixed and evaluated with immunohistochemistry, light microscopy, and electron microscopy. Deconvolution microscopy showed that rhodamine label was concentrated in the plaque shoulder regions of advanced-stage atheromas; however, rhodamine label was not found in adjacent, non-atherosclerotic aorta. Transmission electron microscopy revealed liposome remnants and the highest concentration of nanogold label in lipid-laden areas of atheromas. Liposomes were concentrated in areas of lipoprotein-associated phospholipase A(2) expression. We conclude that modified liposomes can be delivered to the shoulder regions of advanced atheromas in WHHL rabbits and may be useful therapeutically for targeting metabolically active plaque.

Time-trends and congener profiles of PBDEs and PCBs in California peregrine falcons (Falco peregrinus).

High levels (microg/g lw) of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in peregrine falcon eggs from California (n = 90 eggs from 52 birds, 38 nest sites, collected 1986-2007, SigmaPBDEs median = 4.53, range = 0.08-53.1). Over the past 22 years, PBDE levels more than tripled each decade in the eggs, whereas PCB levels had no significant changes. PBDE levels were highest in eggs from major California cities ("Big Cities"), whereas PCBs showed no difference across the regions. For PBDEs, Big City eggs had markedly different patterns from Coastal eggs: BDE-209 and the higher brominated PBDEs (hexa-nona) were dominant congeners in Big City eggs, while BDE-47 and -99 were dominant in Coastal eggs. In many of the birds that gave multiple eggs over time ("time series"), PBDE patterns changed over time: the high proportions of BDE-209 and higher brominated PBDEs (short half-lives) in young birds contrasted with increasingly higher proportions of BDE-153 (long half-life) and other lower brominated PBDEs as the birds aged. These data are consistent with metabolic debromination of BDE-209 (t(1/2) = 1-2 weeks) to the lower brominated PBDEs, with accumulation over time of BDE-153 (t(1/2) = 3-4 years). In contrast, PCB patterns showed no differences by locations, and did not change over time. Diet (prey birds) may explain the urban PBDE pattern, as the patterns in urban pigeons and peregrines were similar, with high proportions of BDE-209 and the higher-brominated PBDEs. Also, our prey data (feathers from peregrine nests) showed urban peregrines having a higher proportion (>2 fold) of granivorous/opportunistic birds (e.g., "introduced feral" pigeons, mourning doves, starlings) in their diet than coastal peregrines. In summary, these data indicate that BDE-209 exits consumer products as an environmental contaminant to be taken up by wildlife (particularly in urban locations), and undergoes metabolic debromination to the banned lower-brominated PBDEs. High levels of the higher-brominated PBDE congeners, especially in urban locations, permitted accurate measures of relative proportions of homologues in each of the hexa-nona congener classes. Using the major hexa-nona homologues in each of these classes, we propose a pathway for the stepwise, metabolic debromination of BDE-209.

Unusual hepta- and octabrominated diphenyl ethers and nonabrominated diphenyl ether profile in California, USA, peregrine falcons (Falco peregrinus): more evidence for brominated diphenyl ether-209 debromination.

High (maximum of 4.1 ppm lipid weight) levels of BDE-209 and other higher brominated diphenyl ethers (BDEs) found in California, USA, peregrine falcon (Falco peregrinus) eggs (n = 95) provided an opportunity to examine homolog profiles of nona-, octa-, and hepta-BDEs as possible evidence for biological debromination of BDE-209. We found two congeners in eggs, an unidentified hepta-BDE (BDE-heptaUNK) and BDE-202 (octa-BDE) that are not present in commercial mixtures. In addition, BDE-208 (nona-BDE) was present at much higher (10-fold) proportions in eggs than in commercial mixtures. To examine whether these unusual homolog patterns arose from assimilation of environmentally degraded BDE commercial mixtures, we compared nona-hepta-BDE homolog profiles of peregrine falcon eggs with those of weathered BDEs present in various abiotic matrices (sludge, sediment, and dusts). We found the profiles differed significantly: BDE-207 was the major nona-BDE in eggs, whereas BDE-206 was the major nona-BDE in abiotic matrices. Thus, the evidence for the biological debromination of BDE-209 in peregrine falcons is twofold: Eggs have two congeners (BDE-202 and -heptaUNK) that are not reported for any commercial mixtures nor in the abiotic matrices examined thus far, and eggs have higher-brominated BDE homolog patterns that are different from those found in commercial mixtures or environmental matrices.

Spatial structure, dispersal, and management of a recovering raptor population.

The recovery of the peregrine falcon (Falco peregrinus anatum) in California has taken place amid strong geographical differences in habitat quality, potentially creating a sink population in the southern coastal habitat and source populations in the northern interior and urban habitats. We analyzed long-term monitoring data to investigate the mechanisms and consequences of spatial structuring for the recovery of this set of nonstable subpopulations. Dispersal rates between habitats were asymmetric, with extremely limited dispersal out of the interior habitat and a strong tendency for birds in the southern coast to disperse to the urban habitats. We used these dispersal estimates and habitat-specific productivity rates to build a set of regional population models that describe population growth within and dispersal between each subpopulation. We tested for the existence of habitat-specific survival and territory acquisition rates by comparing model projections with the number of breeding pairs censused annually in each subpopulation. Our analyses indicate a high rate of survival for interior birds and suggest that both the interior and urban subpopulations were regulated by territory availability over the study period. The inherent spatial structure of this regional peregrine falcon population has had a considerable influence on its recovery and management.

Hemodynamic support with a percutaneous left ventricular assist device during stenting of an unprotected left main coronary artery.

Coronary artery bypass grafting prolongs survival in patients with left main coronary artery stenosis. However, this benefit is denied to patients who refuse the procedure or who are poor surgical candidates due to comorbid conditions. We describe a novel technique for the percutaneous revascularization of stenosis in an unprotected left main coronary artery in high-risk patients. The TandemHeart, a percutaneously inserted left ventricular assist device, was used to provide periprocedural hemodynamic support during angioplasty and stenting of an unprotected left main coronary artery for stenosis in a 70-year-old woman. The device was removed immediately after the procedure, and the patient was discharged from the hospital on the 2nd postprocedural day. The potential advantages of angioplasty with the support of percutaneous left ventricular assist devices in high-risk patients are discussed.

Percutaneous intervention for the treatment of hypoplastic aortoiliac syndrome.

Hypoplastic aortoiliac syndrome (HAIS) occurs in young women and is characterized by a small infrarenal aorta with a hypoplastic iliofemoral arterial system and advanced atherosclerotic disease. Of 304 aortoiliac interventions (AoI), 30 female patients (mean age, 50 +/- 5 years) had HAIS. HAIS patients were less likely to have coronary disease (33% vs. 88%; P < 0.0001) or diabetes (10% vs. 42%; P < 0.001) compared to their AoI counterparts. Twenty-three patients (73%) had hyperlipidemia with mean cholesterol of 287 +/- 42 mg/dl. Twenty-eight patients (93%) were successfully treated with AoI. The ankle/brachial indices improved from pre-AoI ABI of 0.55 +/- 0.1 to post-AoI ABI of 0.99 +/- 0.1. Complications included one groin hematoma and one case of thrombosis. Follow-up averaged 31 months (range, 3-91 months) with an early (less than 12 months) restenosis rate of 7% and late (greater than 12 months) restenosis of 21%. One patient (3%) required surgical revascularization for persistent symptoms. Percutaneous treatment of HAIS is an alternative to surgical revascularization with satisfactory long-term results.

Diabetic patients treated with abciximab and intracoronary stenting.

Diabetic patients are at greater risk for restenosis, recurrent ischemia, and complications following angioplasty than are their nondiabetic counterparts. This is a retrospective study identifying diabetic patients who were treated with abciximab and intracoronary stenting during the period of January 1997 to December 1999. Abciximab was administered to 268 of 707 diabetic patients who received intracoronary stents from 1997 to 1999. The abciximab group contained a higher number of patients with severe ventricular dysfunction and high-grade lesions. Primary endpoints of all-cause mortality, same-vessel revascularization, CABG, TVR, and postprocedural myocardial infarction were similar for both groups. The abciximab group had reduced rates of readmission for cardiac reasons during all follow-up periods. The trends toward improvement of mortality, surgical or percutaneous revascularization, and cardiac readmissions suggest the effect of abciximab may provide benefit for up to 9 months for higher-risk diabetic patients.