12 research outputs found
Total Synthesis of Camptothecin and SN-38
A new practical and concise total synthesis of enantiopure
camptothecin
and SN-38 (14% overall yield, 99.9% ee and 99.9% purity) was described,
starting from inexpensive and readily available materials. The development
of column chromatography-free purification was achieved in all steps,
which offers an economic industrial process to the camptothecin-family
alkaloids
Total Synthesis of Camptothecin and SN-38
A new practical and concise total synthesis of enantiopure
camptothecin
and SN-38 (14% overall yield, 99.9% ee and 99.9% purity) was described,
starting from inexpensive and readily available materials. The development
of column chromatography-free purification was achieved in all steps,
which offers an economic industrial process to the camptothecin-family
alkaloids
Graphic patterns of cortical functional connectivity of depressed patients on the basis of EEG measurements
Considerable evidences have shown a decrease of neu-ronal activity in the left frontal lobe of depressed patients, but the underlying cortical network is still unclear. The present study intends to investigate the conscious-state brain network patterns in depressed patients compared with control individuals. Cortical functional connectivity is quantified by the partial directed coherence (PDC) analysis of multichannel EEG signals from 12 depressed patients and 12 healthy volunteers. The corresponding PDC matrices are first converted into unweighted graphs by applying a threshold to obtain the topographic property in-degree (K in). A significantly larger K in in the left hemisphere is identified in depressed patients, while a symmetric pattern is found in the control group. Another two topographic measures, i.e., clustering coefficients (C) and characteristic path length (L), are obtained from the original weighted PDC digraphs. Compared with control individuals, significantly smaller C and L are revealed in the depression group, indicating a random network-like architecture due to affective disorder. This study thereby provides further support for the presence of a hemispheric asymmetry syndrome in the depressed patients. More importantly, we present evidence that depression is characterized by a loss of optimal small-world network characteristics in conscious state
Multifunctional Nanostructure RAPāRL Rescues Alzheimer's Cognitive Deficits through Remodeling the Neurovascular Unit
Abstract Cerebrovascular dysfunction characterized by the neurovascular unit (NVU) impairment contributes to the pathogenesis of Alzheimer's disease (AD). In this study, a cerebrovascularātargeting multifunctional lipoproteinābiomimetic nanostructure (RAPāRL) constituted with an antagonist peptide (RAP) of receptor for advanced glycation endāproducts (RAGE), monosialotetrahexosyl ganglioside, and apolipoprotein E3 is developed to recover the functional NVU and normalize the cerebral vasculature. RAPāRL accumulates along the cerebral microvasculature through the specific binding of RAP to RAGE, which is overexpressed on cerebral endothelial cells in AD. It effectively accelerates the clearance of perivascular AĪ², normalizes the morphology and functions of cerebrovasculature, and restores the structural integrity and functions of NVU. RAPāRL markedly rescues the spatial learning and memory in APP/PS1 mice. Collectively, this study demonstrates the potential of the multifunctional nanostructure RAPāRL as a diseaseāmodifying modality for AD treatment and provides the proof of concept that remodeling the functional NVU may represent a promising therapeutic approach toward effective intervention of AD