Single-row versus transosseous technique in the arthroscopic treatment of rotator cuff tears: a meta-analysis.

PURPOSE: This study aims to compare single-row suture-anchors (SA) versus transosseous arthroscopic (TO) technique in the treatment of patients with rotator cuff tears in terms of clinical structural outcomes at atleast 24 months of follow-up. METHODS: The systematic review was performed according to "PRISMA guidelines" (Preferred Reporting Items for Systematic Reviews and Meta-analyses), in order to identify all the studies comparing clinical, both subjective and objective, outcomes with 24 months follow-up minimum in patients undergoing arthroscopic RC repair with the SR and TO technique. OVID-MEDLINE®, Cochrane, SCOPUS and PubMed were searched from January 2010 to October 2022 to identify relevant studies, using the following key words, that were combined together to achieve maximum search strategy sensitivity: "Rotator cuff tear" OR "repair" OR "shoulder" OR "reconstruction" OR "suture" OR "arthroscopic" OR "single-row" OR "transosseous". RESULTS: Six papers were finally analyzed in this meta-analysis. The weighted mean difference on Constant scores and for ASES for studies considering suture-anchors (SA) group showed good outcomes. The weighted mean difference of Constant scores and of ASES for TO (transosseous) group showed good outcomes. The weighted mean difference of CONSTANT for TO versus SA groups showed no differences in the outcomes of SA and TO techniques for the repair of Rotator Cuff Tears at minimum 24 months follow-up. CONCLUSIONS: The Arthroscopic transosseous rotator cuff repair technique and SA (suture-anchor) technique both lead to significant short-term improvement and satisfactory subjective outcome scores with low complication/failure rates. No differences were found in the final outcome between the two techniques.

Evidence that the transition of HIV-1 gp41 into a six-helix bundle, not the bundle configuration, induces membrane fusion.

Many viral fusion proteins exhibit a six-helix bundle as a core structure. HIV Env-induced fusion was studied to resolve whether membrane merger was due to the transition into the bundle configuration or occurred after bundle formation. Suboptimal temperature was used to arrest fusion at an intermediate stage. When bundle formation was prevented by adding inhibitory peptides at this stage, membranes did not merge upon raising temperature. Inversely, when membrane merger was prevented by incorporating lysophosphatidylcholine (LPC) into cell membranes at the intermediate, the bundle did not form upon optimizing temperature. In the absence of LPC, the six-helix bundle did not form when the temperature of the intermediate was raised for times too short to promote fusion. Kinetic measures showed that after the temperature pulse, cells had not advanced further toward fusion. The latter results indicate that bundle formation is the rate-limiting step between the arrested intermediate and fusion. Electrical measures showed that the HIV Env-induced pore is initially large and grows rapidly. It is proposed that bundle formation and fusion are each contingent on the other and that movement of Env during its transition into the six-helix bundle directly induces the lipid rearrangements of membrane fusion. Because peptide inhibition showed that, at the intermediate stage, the heptad repeats of gp41 have become stably exposed, creation of the intermediate could be of importance in drug and/or vaccine development.

Heptad-repeat regions of respiratory syncytial virus F1 protein form a six-membered coiled-coil complex.

The Respiratory Syncytial Virus (RSV) fusogenic glycoprotein F(1) was characterized using biochemical and biophysical techniques. Two heptad-repeat (HR) regions within F(1) were shown to interact. Proteinase-K digestion experiments highlight the HR1 region (located proximal to the fusion peptide sequence) of the F(1) protein to which an HR2-derived (located proximal to the membrane-spanning domain) peptide binds, thus protecting both the protein and peptide from digestion. Solution-phase analysis of HR1-derived peptides shows that these peptides adopt helical secondary structure as measured by circular dichroism. Sedimentation equilibrium studies indicate that these HR1 peptides self-associate in a monomer/trimer equilibrium with an association constant of 5.2 x 10(8) M(-2). In contrast, HR2-derived peptides form random monomers in solution. CD analysis of mixtures containing peptides from the two regions demonstrate their propensity to interact and form a very stable (T(m) = 87 degrees C), helical (86% helicity) complex comprised of three HR1 and three HR2 members.