PCR to CRISPR: Role of Nucleic Acid Tests (NAT) in detection of COVID-19.

COVID-19 infection has emerged as an unparalleled pandemic with morbidity and mortality tolls challenging diagnostic approaches and therapeutic interventions, and raising serious questions for healthcare policy-makers. From the diagnostic perspective, Reverse transcriptase polymerase chain reaction remains the gold standard. However, issues associated with gene primer variation in different countries, low analytical sensitivity, cross-reactivity with certain human coronaviruses have raised serious concerns within the scientific community. Alongside longer turnaround times, requirements of sophisticated equipment and trained technicians are the other challenges for conventional reverse transcriptase polymerase chain reaction testing. The recent biotechnological boom has now allowed newer nucleic acid testing options for diagnosing severe acute respiratory syndrome Coronovairus 2 (SARS-CoV2) with much better diagnostic efficiency, reduced turnaround times and possible benefit for use as a point-of-care test. Isothermal techniques with simple equipment requirements along with uniform temperature for analysis have emerged to be more sensitive and specific with turnaround times as low as 10-15 minutes. Similarly, Cluster Regularly Interspaced Short Palindromic Repeats have also been seen to play a very decisive role in COVID-19 diagnostics with much superior diagnostic efficiency and feasibility as a point-of-care test and its possible use for sequencing. The current narrative review was planned to consolidate data for all possible nucleic acid testing options under research/clinical use, and to provide a comparative assessment from the perspective of both the clinician and the laboratory.

Short-term liver transplant outcomes from SARS-CoV-2 lower respiratory tract NAT positive donors.

On April 2021, the United States Organ Procurement and Transplantation Executive Committee approved the "lower respiratory SARS-CoV-2 testing for lung donors" emergency policy upon recommendation from the Ad Hoc Disease Transmission Advisory Committee. This policy requires that all lung donors be tested for SARS-CoV-2 in a lower respiratory specimen by nucleic acid test (NAT) and that the results be available before the lungs are transplanted. The overarching goal of the emergency policy was to minimize the risk of donor-derived COVID-19 to lung recipients. However, an unintended consequence of the policy was the emergence of a new population of potential donors: the SARS-CoV-2 lower respiratory tract (LRT) NAT positive donor. We describe the use of two SARS-CoV-2 LRT NAT positive liver donors without a known history of COVID-19 infection with adequate short-term outcomes. The recipients did not have a prior history of COVID-19, nor did they receive monoclonal antibodies post-transplantation; one was unvaccinated. If the safety and long-term outcomes from SARS-CoV-2 LRT NAT positive donors are confirmed in larger studies, this strategy represents a promising way to increase the pool for organ donation.

Structural features of an acidic polysaccharide with the potential of promoting osteoblast differentiation from Lycium ruthenicum Murr.

The enhanced osteoblast differentiation is beneficial to the prevention of osteoporosis. In this study, a homogeneous polysaccharide (LRP-S2A) with the potential of promoting osteoblast differentiation was obtained from the fruits of Lycium ruthenicum, a traditional herb for treatment of postmenopausal metabolic disorders. Structural identification indicated that LRP-S2A, with a relative molecular weight of 2.65 × 106 Da and an uronic acid content of 41.8%, contained Rha, Ara, Gal, Glc and GlcA in a molar ratio of 1.00 : 2.07 : 0.57 : 2.59 : 4.33 and was composed of a backbone consisting of 6-O-Me-α-(1→4)-D-GlcpA, 2-O-acetyl-α-(1→4)-D-Glcp, α-(1→2,4)-L-Rhap, ß-(1→3)-D-Galp andα-(1→3,5)-L-Araf, and some branches consisting of 6-O-Me-α-(1→4)-D-GlcpA and terminal α-L-Araf. These results suggested that LRP-S2A with the potential of promoting osteoblast differentiation was a new acidic polysaccharide.