Objectives To characterize the morphological features of plaque erosion and calcified nodule in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT). Background Plaque erosion and calcified nodule have not been systematically investigated in vivo. Methods One hundred and twenty-six patients with ACS who had undergone pre-intervention OCT imaging were included. The culprit lesions were classified as plaque rupture (PR), erosion (OCT-erosion), calcified nodule (OCT-CN), or others using a new set of diagnostic criteria for OCT. Results The incidences of PR, OCT-erosion, and OCT-CN were 43.7%, 31.0%, and 7.9%, respectively. Patients with OCT-erosion were the youngest compared with those with PR and OCT-CN (53.8±13.1 years vs. 60.6±11.5 years, 65.1±5.0 years, p=0.005). Compared with patients with PR, presentation with non-ST-segment elevation ACS (NSTE-ACS) was more common in patients with OCT-erosion (61.5% vs. 29.1%, p=0.008) and OCT-CN (100% vs. 29.1%, p<0.001). OCT-erosion had a lower frequency of lipid plaque (43.6% vs. 100%, p<0.001), thicker fibrous cap (169.3±99.1 μm vs. 60.4±16.6 μm, p<0.001), and smaller lipid arc (202.8±73.6° vs. 275.8±60.4°, p<0.001) than PR. The diameter stenosis was least severe in OCT-erosion followed by OCT-CN and PR (55.4±14.7% vs. 66.1±13.5% vs. 68.8±12.9%, p<0.001). Conclusions OCT is a promising modality for identifying OCT-erosion and OCT-CN in vivo. OCT-erosion is a frequent finding in patients with ACS, especially in those with NSTE-ACS and younger patients. OCT-CN is the least common etiology for ACS and is more common in older patients.

Lymphatic vessels develop from specialized endothelial cells in preexisting blood vessels, but the molecular signals that regulate this separation are unknown. Here we identify a failure to separate emerging lymphatic vessels from blood vessels in mice lacking the hematopoietic signaling protein SLP-76 or Syk. Blood-lymphatic connections lead to embryonic hemorrhage and arteriovenous shunting. Expression of slp-76 could not be detected in endothelial cells, and blood-filled lymphatics also arose in wild-type mice reconstituted with SLP-76 -deficient bone marrow. These studies reveal a hematopoietic signaling pathway required for separation of the two major vascular networks in mammals.Mammals have two circulatory systems, a closed blood vasculature and an open lymphatic vasculature, that operate in parallel but develop in series (1,2). Although derived from venous endothelial precursors, lymphatic vessels do not communicate with blood vessels except at a single point where the thoracic duct empties into the subclavian vein (1-3). Recent studies have identified specific transcription factors and growth factors required to regulate the development † To whom correspondence should be addressed.

SLP76 and SLP65 are adaptor proteins that lack intrinsic enzymatic activity but contain multiple protein-binding domains. These proteins are essential for signalling downstream of integrins and receptors that contain immunoreceptor tyrosine-based activation motifs. The absence of these adaptor proteins profoundly affects various lineages in the haematopoietic compartment and severely compromises vascular development, highlighting their importance as regulators of signalling cascades. In this Review, we discuss the role of SLP76 and SLP65 in several signalling pathways in haematopoietic cells, with an emphasis on recent studies that provide insight into their mechanisms of action.

Mice engineered to express a transgene encoding a human Cu/Zn superoxide dismutase (SOD1) with a Gly93 → Ala (G93A) mutation found in patients who succumb to familial amyotrophic lateral sclerosis (FALS) develop a rapidly progressive and fatal motor neuron disease (MND) similar to amyotrophic lateral sclerosis (ALS). Hallmark ALS lesions such as fragmentation of the Golgi apparatus and neurofilament (NF)-rich inclusions in surviving spinal cord motor neurons as well as the selective degeneration of this population of neurons were also observed in these animals. Since the mechanism whereby mutations in SOD1 lead to MND remains enigmatic, we asked whether NF inclusions in motor neurons compromise axonal transport during the onset and progression of MND in a line of mice that contained ∼30% fewer copies of the transgene than the original G93A (Gurney et al., 1994). The onset of MND was delayed in these mice compared to the original G93A mice, but they developed the same neuropathologic abnormalities seen in the original G93A mice, albeit at a later time point with fewer vacuoles and more NF inclusions. Quantitative Western blot analyses showed a progressive decrease in the level of NF proteins in the L5 ventral roots of G93A mice and a concomitant reduction in axon caliber with the onset of motor weakness. By ∼200 d, both fast and slow axonal transports were impaired in the ventral roots of these mice coincidental with the appearance of NF inclusions and vacuoles in the axons and perikarya of vulnerable motor neurons. This is the first demonstration of impaired axonal transport in a mouse model of ALS, and we infer that similar impairments occur in authentic ALS. Based on the temporal correlation of these impairments with the onset of motor weakness and the appearance of NF inclusions and vacuoles in vulnerable motor neurons, the latter lesions may be the proximal cause of motor neuron dysfunction and degeneration in the G93A mice and in FALS patients with SOD1 mutations.