SARS-CoV-2 Spike Protein Disrupts Blood–Brain Barrier Integrity via RhoA Activation

The SARS-CoV-2 spike protein has been shown to disrupt blood–brain barrier (BBB) function, but its pathogenic mechanism of action is unknown. Whether angiotensin converting enzyme 2 (ACE2), the viral binding site for SARS-CoV-2, contributes to the spike protein-induced barrier disruption also remains unclear. Here, a 3D-BBB microfluidic model was used to interrogate mechanisms by which the spike protein may facilitate barrier dysfunction. The spike protein upregulated the expression of ACE2 in response to laminar shear stress. Moreover, interrogating the role of ACE2 showed that knock-down affected endothelial barrier properties. These results identify a possible role of ACE2 in barrier homeostasis. Analysis of RhoA, a key molecule in regulating endothelial cytoskeleton and tight junction complex dynamics, reveals that the spike protein triggers RhoA activation. Inhibition of RhoA with C3 transferase rescues its effect on tight junction disassembly. Overall, these results indicate a possible means by which the engagement of SARS-CoV-2 with ACE2 facilitates disruption of the BBB via RhoA activation. Understanding how SARS-CoV-2 dysregulates the BBB may lead to strategies to prevent the neurological deficits seen in COVID-19 patients.

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Central Venous Catheter Protective Connector Caps Reduce Intraluminal Catheter-Related Infection

BackgroundCentral line-associated blood stream infection (CLABSI) rates in adult care intensive care units have been decreasing across the board. However, we continued to see just a few infections in patients whose catheters are in for >4 days. Therefore, we looked at infections associated with intraluminal contamination to help reduce our infection rate.MethodsA protective cap trial was developed and implemented in 2 intensive care units. All of the central venous catheter and intravenous tubing access valves were covered with a protective cap saturated with alcohol. This intervention eliminated the need to wipe off intravenous access points with an alcohol swab. The study was done as a nonrandomized prospective trial occurring March 1, 2011 through February 29, 2012.ResultsDuring 2010, there were 4 CLABSI-related infections. By the end of the trial, we had incurred 1 catheter-associated blood stream infection. CLABSI rate reduced from 1.9 in 2010 to 0.5 during the 1-year trial period.ConclusionsThe implementation of the port protector cap system resulted in lower infection rates compared with an alcohol swab technique. Our results indicate that consistent use of the caps in tandem with strict compliance does influence CLABSI rates.     

Posterior cortical atrophy: a single case cognitive and radiological follow-up

Posterior cortical atrophy (PCA) is a rare neurodegenerative syndrome characterized by initial predominant visuoperceptual deficits followed by a progressive decline in other cognitive functions. This syndrome has not been as thoroughly described as other dementias, particularly from a neuropsychological evolution perspective with only a few studies describing the evolution of its cognitive progression. In this investigation we review the literature on this rare condition and we perform a 7-year neuropsychological and neuroradiological follow-up of a 64-year-old man with PCA. The subject’s deficits initially appeared in his visuoperceptual skills with later affectation appearing in language and other cognitive functions, this being coherent with the patient’s parieto-temporal atrophy evolution.     

Human fluids alter DNA-acquisition in Acinetobacter baumannii

Transformation is one of the mechanisms of acquisition of foreign genetic material leading to the emergence of multidrug resistant (MDR) bacteria. Recently, human serum albumin (HSA) was shown to specifically increase transformation frequency in the nosocomial pathogen Acinetobacter baumannii. To further assess the relevance of HSA as a possible modulator of A. baumannii transformation in host-pathogen interactions, in this work we examined the effect of different human fluids. We observed a significant increase in transformation frequencies in the presence of pleural fluid, whole blood cells and liquid ascites, and to a lesser extent with urine. The observed effects correlate with both HSA and bacterial content found in the assayed patient fluids. Taken together, these results are in agreement with our previous findings that highlight HSA as a possible host signal with the ability to trigger natural transformation in A. baumannii.     

Determination of Chemical Antioxidants and Phenolic Compounds in the Brazilian Mushroom Agaricus sylvaticus

Agaricus sylvaticus mushroom has been widely studied because of its high nutritional value and medicinal properties. The objective of this study was to evaluate the antioxidant potential of both alcoholic and aqueous extracts of Agaricus sylvaticus and quantify their total polyphenol content. The antioxidant activity was performed by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity and total polyphenol content was assessed by colorimetric method. Observation also noted the great antioxidant potential of aqueous, alcoholic and ethereal extracts (14.6%, 75.6% and 14.6%, respectively) of the Agaricus sylvaticus mushroom, highlighting the alcoholic extract, which demonstrates the extraordinary benefits of this mushroom in the diet, since antioxidants prevent premature ageing and various types of cancer.