The pathophysiology of chronic subdural hematoma revisited: emphasis on aging processes as key factor

GeroScience - Chronic subdural hematoma (CSH) affects mostly elderly subjects. Previously, pathophysiological concepts suggested that CSH is secondary to degradation of subdural collections of...     

Change of the mechanical properties of two different balloon catheters with increasing numbers of cycles of resterilization.

An increasing number of centers are reusing PTCA catheters even though manufacturers warrant single use only. This prospective bench laboratory trial addresses the quality of PTCA balloon catheters after up to three resterilization cycles in order to determine whether a larger trial is warranted to discern whether catheters should be reused. Forty PTCA catheters from two different manufacturers (nominal diameters 1.5 and 3.0 mm) were taken from the shelf. An independent institute tested mechanical properties such as burst pressure, nominal diameter, crossing profile, and balloon surface. The crossing profile increased by 22.5%-39.2% with no additional deterioration after repeated sterilizations. The nominal diameter either increased or decreased by a maximum of 47%. In all 1.5 mm balloons, the burst pressure remained above the manufacturers' values, whereas in the 3.0 mm balloons, the value dropped below the rated burst pressure in 40%-50% of the trials. In conclusion, in both catheter types analyzed, reuse was associated with a considerably worse quality, which puts in question their routine clinical use.     

Anti-human immunodeficiency virus noncytolytic CD8+ T-cell response: a review

The CD8+ T-cell immune response for human immunodeficiency virus (HIV) is divided into a cytolytic and noncytolytic mechanism. The mechanism of cell-mediated cytotoxic immunity for the partial control of human immunodeficiency virus type 1 (HIV-1) replication in infected individuals is well-characterized, and the direct killing of virus-infected cells by antigen-specific cytotoxic T-lymphocytes (CTL) is widely correlated with disease outcome. However, the mechanism of the noncytolytic component is not well understood. In part, this is because the main inhibitory factor or factors called CD8+ T-cell antiviral factor (CAF), have not yet been purified. In addition, results between the investigators are difficult to compare because of technical differences between laboratories, including the use of different in vitro cell expansion and stimulation methods for the CD8+ T cells, the necessity of sequential biochemical purification steps with restricted amounts of material, the complex analysis and interpretation of gene expression arrays, the use of different HIV strains, and the use of different short- or long-term inhibition assays using primary or immortalized target cells. Nevertheless, the diminishing efficacy of highly active antiretroviral therapy (HAART) because of the development of resistant HIV and the persistence of latent HIV provides a strong rationale for an immune therapy approach using antiviral factor(s) of the CD8+ T-cell noncytolytic immune response.     

Elevated antigen-specific Th2 type response is associated with the poor prognosis of hand,foot and mouth disease

The immunopathogenesis of severe hand, foot and mouth disease (HFMD) remains elusive. This study revealed that enterovirus 71 (EV71) epitope-specific CD4+ T cell responses of HFMD patients were skewed toward a Th2 cytokine profile. Patients that demonstrated higher levels of IL-4 expression in their CD4 T cells following antigen stimulation in vitro tended to have a more prolonged period of high fevers and a longer duration of illness. Thus, an increase of EV71 epitope-specific Th2 type response may portend the poor prognosis for some HFMD patients.     

Ephrin-B2 controls PDGFRβ internalization and signaling

B-class ephrins, ligands for EphB receptor tyrosine kinases, are critical regulators of growth and patterning processes in many organs and species. In the endothelium of the developing vasculature, ephrin-B2 controls endothelial sprouting and proliferation, which has been linked to vascular endothelial growth factor (VEGF) receptor endocytosis and signaling. Ephrin-B2 also has essential roles in supporting mural cells (namely, pericytes and vascular smooth muscle cells [VSMCs]), but the underlying mechanism is not understood. Here, we show that ephrin-B2 controls platelet-derived growth factor receptor β (PDGFRβ) distribution in the VSMC plasma membrane, endocytosis, and signaling in a fashion that is highly distinct from its role in the endothelium. Absence of ephrin-B2 in cultured VSMCs led to the redistribution of PDGFRβ from caveolin-positive to clathrin-associated membrane fractions, enhanced PDGF-B-induced PDGFRβ internalization, and augmented downstream mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK) activation but impaired Tiam1–Rac1 signaling and proliferation. Accordingly, mutant mice lacking ephrin-B2 expression in vascular smooth muscle developed vessel wall defects and aortic aneurysms, which were associated with impaired Tiam1 expression and excessive activation of MAP kinase and JNK. Our results establish that ephrin-B2 is an important regulator of PDGFRβ endocytosis and thereby acts as a molecular switch controlling the downstream signaling activity of this receptor in mural cells.     

Virus species polemics: 14 senior virologists oppose a proposed change to the ICTV definition of virus species

The Executive Committee of the International Committee on Taxonomy of Viruses (ICTV) has recently decided to modify the current definition of virus species (Code of Virus Classification and Nomenclature Rule 3.21) and will soon ask the full ICTV membership (189 voting members) to ratify the proposed controversial change. In this discussion paper, 14 senior virologists, including six Life members of the ICTV, compare the present and proposed new definition and recommend that the existing definition of virus species should be retained. Since the pros and cons of the proposal posted on the ICTV website are not widely consulted, the arguments are summarized here in order to reach a wider audience.     

Objectively characterizing Huntington’s disease using a novel upper limb dexterity test

Journal of Neurology - The Clinch Token Transfer Test (C3t) is a bi-manual coin transfer task that incorporates cognitive tasks to add complexity. This study explored the concurrent and convergent...