SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion

The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era

Imaging in Prostate Cancer Diagnosis: Present Role and Future Perspectives.

Prostate cancer (PCa) remains a major health concern for the male population. Detection and primary diagnosis of PCa are based on digital rectal examination, serum prostate-specific antigen levels, and transrectal ultrasound (TRUS)-guided random biopsy. Moreover, the gold standard for detecting PCa, systematic biopsy, lacks sensitivity as well as grading accuracy. This review summarizes recent developments of ultrasonography modalities and functional magnetic resonance imaging (MRI) in the diagnosis of PCa. A comparison between the different methods is presented, including their clinical value and usefulness. It is concluded that innovative ultrasound techniques (including ultrasound contrast agents, 3-D and 4-D sonography, elastography and harmonic sonography) promise benefits in comparison to standard TRUS to accurately diagnose PCa. Promising advances have been made in the detection of PCa with multiparametric MRI. The combination of conventional and functional MRI techniques (including diffusion-weighted imaging, dynamic contrast-enhanced MRI, and MR spectroscopy) can provide information for differentiating PCa from noncancerous tissue and can be used for MRI-guided biopsies, especially in patients with persistent elevation of serum prostate-specific antigen and previous negative TRUS-guided biopsies. However, functional MRI technique and MRI-guided biopsy remain expensive and complex tools presenting inherent challenges