35 research outputs found
Natriuretic peptide receptor-C is up-regulated in the intima of advanced carotid artery atherosclerosis
OBJECTIVE: Natriuretic peptide receptor-C (NPR-C/NPR-3) is a cell surface protein involved in vascular remodelling that is up-regulated in atherosclerosis. NPR-C expression has not been well characterized in human carotid artery occlusive lesions. We hypothesized that NPR-C expression correlates with intimal features of vulnerable atherosclerotic carotid artery plaque. METHODS: To test this hypothesis, we evaluated NPR-C expression by immunohistochemistry (IHC) in carotid endarterectomy (CEA) specimens isolated from 18 patients. The grade, location, and co-localization of NPR-C in CEA specimens were evaluated using two tissue analysis techniques. RESULTS: Relative to minimally diseased CEA specimens, we observed avid NPR-C tissue staining in the intima of maximally diseased CEA specimens (65%; p=0.06). Specifically, maximally diseased CEA specimens demonstrated increased NPR-C expression in the superficial intima (61%, p=0.17), and deep intima (138% increase; p=0.05). In the superficial intima, NPR-C expression significantly co-localized with vascular smooth muscle cells (VSMCs) and macrophages. The intensity of NPR-C expression was also higher in the superficial intima plaque shoulder and cap regions, and significantly correlated with atheroma and fibroatheroma vulnerable plaque regions (β=1.04, 95% CI=0.46, 1.64). CONCLUSION: These findings demonstrate significant NPR-C expression in the intima of advanced carotid artery plaques. Furthermore, NPR-C expression was higher in vulnerable carotid plaque intimal regions, and correlate with features of advanced disease. Our findings suggest that NPR-C may serve as a potential biomarker for carotid plaque vulnerability and progression, in patients with advanced carotid artery occlusive disease
Transchest defibrillation under conditions of hypothermia
This study was conducted to determine whether or not hypothermia changes ventricular defibrillation threshold. Ventricular fibrillation was induced by electrical stimulation of the endocardium in pentobarbital anesthetized dogs, both during normothermia and hypothermia produced by circulating 8 °C water through a rubber bladder implanted in the peritoneal cavity. Defibrillation threshold was determined as the shock strength needed to defibrillate the ventricles and differing no more than 10 percent from a shock strength that failed to defibrillate. Defibrillation threshold current was stable for body temperatures ranging from 37 oC to 22 oC. Threshold energy increased linearly with decreasing temperature in keeping with the expected temperature-dependent changes in body fluid resistance. Normothermic electrical doses are probably appropriate for defibrillation of hypothermic children
Magnetostriction and magnetic texture to 97.4 Tesla in frustrated SrCu2(BO3)2
Strong geometrical frustration in magnets leads to exotic states, such as
spin liquids, spin supersolids and complex magnetic textures. SrCu2(BO3)2, a
spin-1/2 Heisenberg antiferromagnet in the archetypical Shastry-Sutherland
lattice, exhibits a rich spectrum of magnetization plateaus and stripe-like
magnetic textures in applied fields. The structure of these plateaus is still
highly controversial due to the intrinsic complexity associated with
frustration and competing length scales. We reveal new magnetic textures in
SrCu2(BO3)2 via magnetostriction and magnetocaloric measurements in fields up
to 97.4 Tesla. In addition to observing the low-field fine structure of the
plateaus with unprecedented resolution, the data also reveal lattice responses
at 82 T and at 73.6 T which we attribute, using a controlled density matrix
renormalization group approach, to the long-predicted 1/2-saturation plateau,
and to a new 2/5 plateau.Comment: 12 pages, 4 figures, submitte