Vessel segmentation analysis of ischemic stroke images acquired with photoacoustic microscopy

We have applied optical-resolution photoacoustic microscopy (OR-PAM) for longitudinal monitoring of cerebral metabolism through the intact skull of mice before, during, and up to 72 hours after a 1-hour transient middle cerebral artery occlusion (tMCAO). The high spatial resolution of OR-PAM enabled us to develop vessel segmentation techniques for segment-wise analysis of cerebrovascular responses

Dexmedetomidine Reduces Incidences of Ventricular Arrhythmias in Adult Patients: A Meta-Analysis.

PURPOSE: To assess the antiarrhythmic properties of dexmedetomidine in patients in the intensive care unit. METHODS: A literature review was conducted with Ovid MEDLINE (R), Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase, and Scopus. RESULTS: We identified 6 out of 126 studies that met the selection criteria for our meta-analysis, all of which focused on the perioperative cardiac surgery period. Patients receiving dexmedetomidine demonstrated a significant reduction of the overall incidence of ventricular arrhythmias (RR 0.35, 95% CI 0.16, 0.76). In particular, dexmedetomidine significantly decreased the risk of ventricular tachycardia compared with control (RR 0.25, 95% CI 0.08, 0.80, I CONCLUSION: From this meta-analysis, we report a decreased incidence of ventricular tachycardia with dexmedetomidine in critically ill patients. This result favors the use of dexmedetomidine for its antiarrhythmic properties

CNS Neurons Deposit Laminin α5 to Stabilize Synapses

Summary: Synapses in the developing brain are structurally dynamic but become stable by early adulthood. We demonstrate here that an α5-subunit-containing laminin stabilizes synapses during this developmental transition. Hippocampal neurons deposit laminin α5 at synapses during adolescence as connections stabilize. Disruption of laminin α5 in neurons causes dramatic fluctuations in dendritic spine head size that can be rescued by exogenous α5-containing laminin. Conditional deletion of laminin α5 in vivo increases dendritic spine size and leads to an age-dependent loss of synapses accompanied by behavioral defects. Remaining synapses have larger postsynaptic densities and enhanced neurotransmission. Finally, we provide evidence that laminin α5 acts through an integrin α3β1-Abl2 kinase-p190RhoGAP signaling cascade and partners with laminin β2 to regulate dendritic spine density and behavior. Together, our results identify laminin α5 as a stabilizer of dendritic spines and synapses in the brain and elucidate key cellular and molecular mechanisms by which it acts. : In the developing brain, synaptic structure transitions from dynamic to stable by early adulthood. Omar et al. identify a laminin molecule deposited at synapses in the brain that is essential for dendritic spine structural regulation and synapse stability between early postnatal development and adulthood. Keywords: extracellular matrix, ECM, synapse maturation, adhesion, Lama5, Lamb2, synapse loss, stability, structural plasticity, motilit

Is Levodopa Response a Valid Indicator of Parkinson\u27s Disease?

BACKGROUND: The clinical diagnosis of Parkinson\u27s disease (PD) requires the presence of parkinsonism and supportive criteria that include a clear and dramatic beneficial response to dopaminergic therapy. Our aim was to test the diagnostic criterion of dopaminergic response by evaluating its association with pathologically confirmed diagnoses in a large population of parkinsonian patients. METHODS: We reviewed clinical data maintained in an electronic medical record from all patients with autopsy data who had been seen in the Movement Disorders Center at Washington University, St. Louis, between 1996 and 2018. All patients with parkinsonism who underwent postmortem neuropathologic examination were included in this analysis. RESULTS: There were 257 unique parkinsonian patients with autopsy-based diagnoses who had received dopaminergic therapy. Marked or moderate response to dopaminergic therapy occurred in 91.2% (166/182) of those with autopsy-confirmed PD, 52.0% (13/25) of those with autopsy-confirmed multiple systems atrophy, 44.4% (8/18) of those with autopsy-confirmed progressive supranuclear palsy, and 1 (1/8) with autopsy-confirmed corticobasal degeneration. Other diagnoses were responsible for the remaining 24 individuals, 9 of whom had a moderate response to dopaminergic therapy. CONCLUSION: A substantial response to dopaminergic therapy is frequent but not universal in PD. An absent response does not exclude PD. In other neurodegenerative disorders associated with parkinsonism, a prominent response may also be evident, but this occurs less frequently than in PD. © 2020 International Parkinson and Movement Disorder Society

Is Levodopa Response a Valid Indicator of Parkinson's Disease?

OBJECTIVE/BACKGROUND: The clinical diagnosis of Parkinson disease (PD) requires the presence of parkinsonism and supportive criteria that include a clear and dramatic beneficial response to dopaminergic therapy. Our objective was to test the diagnostic criterion of dopaminergic response by evaluating its association with pathologically confirmed diagnoses in a large population of parkinsonian patients. METHODS: We reviewed clinical data maintained in an electronic medical record from all patients with autopsy data who had been seen in the Movement Disorders Center at Washington University, St. Louis between 1996 and 2018. All patients with parkinsonism who underwent postmortem neuropathologic examination were included in this analysis. RESULTS: There were 257 unique parkinsonian patients with autopsy-based diagnoses who had received dopaminergic therapy. Marked or moderate response to dopaminergic therapy occurred in 91.2% (166/182) of those with autopsy-confirmed PD, 52.0% (13/25) of those with autopsy-confirmed multiple systems atrophy, 44.4% (8/18) with autopsy-confirmed progressive supranuclear palsy, and one (1/8) with autopsy-confirmed corticobasal degeneration. Other diagnoses were responsible for the remaining 24 individuals, 9 of whom had a moderate response to dopaminergic therapy. CONCLUSION: A substantial response to dopaminergic therapy is frequent but not universal in PD. An absent response does not exclude PD. In other neurodegenerative disorders associated with parkinsonism, a prominent response may also be evident but this occurs less frequently than in PD