A Coronin 1-Derived Peptide Inhibits Membrane Fusion by Modulating Membrane Organization and Dynamics.

Membrane fusion is considered the first step in the entry of enveloped viruses into the host cell. Several targeted strategies have been implemented to block viral entry by limiting the fusion protein to form a six-helix bundle, which is a prerequisite for fusion. Nonetheless, the development of broad-spectrum fusion inhibitors is essential to combat emerging and re-emerging viral infections. TG-23, a coronin 1, a tryptophan-aspartate-rich phagosomal protein-derived peptide, demonstrated inhibition of fusion between small unilamellar vesicles (SUVs) by modulating the membrane's physical properties. However, its inhibitory efficacy reduces with an increasing concentration of membrane cholesterol. The present work aims to develop a fusion inhibitor whose efficacy would be unaltered in the presence of membrane cholesterol. A stretch of the tryptophan-aspartic acid-containing peptide with a similar secondary structure and hydrophobicity profile of TG-23 from coronin 1 was synthesized, and its ability to inhibit SUV-SUV fusion with varying concentrations of membrane cholesterol was evaluated. Our results demonstrate that the GG-21 peptide inhibits fusion irrespective of the cholesterol content of the membrane. We have further evaluated the peptide-induced change in the membrane organization and dynamics utilizing arrays of steady-state and time-resolved fluorescence measurements and correlated these results with their effect on fusion. Interestingly, GG-21 displays inhibitory efficacy in a wide variety of lipid compositions despite having a secondary structure and physical properties similar to those of TG-23. Overall, our results advocate that the secondary structure and physical properties of the peptide may not be sufficient to predict its inhibitory efficacy.

Choline chloride and ethylene glycol based deep eutectic solvent (DES) versus hydroxyl functionalized room temperature ionic liquids (RTILs): assessing the differences in microscopic behaviour between the DES and RTILs.

With the aim of understanding the differences in the behavior of deep eutectic solvents (DESs) and room temperature ionic liquids (RTILs) in terms of their structure, dynamics, and intra- and intermolecular interactions, three different ILs and one DES having similar functionalities (hydroxyl) have been investigated by using both ensembled average and single-molecule spectroscopic techniques. Specifically, for this purpose, a choline chloride based DES (ethaline) and three hydroxyl functionalized ILs (1-(2-hydroxyethyl)-3-imidazolium bis(trifluoromethanesulfonyl)imide ([OHEMIM][NTF2]), N-(2-hydroxyl ethyl)-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([OHEMPy][NTf2]), and N-(2-hydroxyethyl)-N,N-dimethylpropan-1-aminium bis(trifluoromethanesulfonyl)imide ([OHC3CH][NTf2])) are employed and investigated by EPR, time-resolved fluorescence, NMR and FCS studies. Estimation of polarity through EPR spectroscopy has revealed that the hydroxyl ILs employed in these studies are hyper-polar (close to water) in nature, whereas the polarity of the DES is found to be close to those of aliphatic polyhydroxy-alcohols. Interestingly, both time-resolved fluorescence anisotropy and FCS studies on these systems have suggested that the hydroxyl ILs are more dynamically heterogeneous than the DES. More interestingly, PFG-NMR measurements have indicated that the fluid structure of ethaline is relatively more associated as compared to those of the ILs despite the fact that all the cations have the same hydroxyl functionalities. All these investigations have essentially demonstrated that, despite having similar functionalities, both the DES and hydroxyl ILs employed in the present study exhibit microscopic behaviours that are significantly different from each other, indicating the interplay of various intermolecular interactions within the constituent species in governing the behaviours of these solvent systems.

Bilateral ACL Reconstructions with Hamstring Autografts.

Bilateral anterior cruciate ligament (ACL) injuries are rare with incidence between 2 and 4%, and presently no definitive guidelines for proper management exist. Ideal treatment protocol remains controversial between a single-stage and two-stage bilateral ACL reconstruction. The purpose of this study is to evaluate the outcome of single-stage bilateral ACL reconstruction with hamstring tendon autografts in bilateral ACL injuries. A prospective study was undertaken including a total of 14 consecutive patients with bilateral ACL deficient knee who underwent single-stage bilateral ACL reconstruction with hamstring tendon autograft with a mean follow-up duration of 28 months (24-38 months). Functional outcomes were evaluated by range of movements, International Knee Documentation Committee (IKDC), Lysholm and Tegner activity score, and stability tests. The mean age was 30 years (range 18-42 years). Average duration of rehabilitation was 8 weeks. Time to return to full-time work and full sports was 5.6 weeks and 6.2 months, respectively. Clinical examination demonstrated full range of motion; a total of 12 patients (86%) had a negative Lachman test and 13 patients (93%) had a negative pivot shift at the final follow-ups. The mean IKDC evaluation score was 89 points, the mean Tegner activity score was 7 points, and the mean Lysholm knee score was 91 points. A total of 12 patients (86%) returned to their preinjury level of activity and an overall greater than 90% satisfaction rate was achieved. Single-stage bilateral ACL reconstruction using hamstring autografts is clinically safe, effective, and cost-effective with better patient compliance and with comparable functional outcome as opposed to two-stage ACL reconstructions.

Intra-articular Adjuvant Analgesics following Knee Arthroscopy: Comparison between Single and Double Dose Dexmedetomidine and Ropivacaine A Multicenter Prospective Double-blind Trial.

OBJECTIVE: Knee arthroscopy is a commonly performed orthopedic procedure. Post-operatively, adequate pain relief reduces the surgical stress response and patient's morbidity and facilitates rehabilitation. The analgesic effect of dexmedetomidine (2 µg/kg body weight) as an adjunct to ropivacaine in knee arthroscopic knee procedures was studied to determine whether this would achieve longer post-operative analgesia and whether the study dosage of dexmedetomidine was safe and free of adverse effects. PATIENTS AND METHODS: In a multicenter prospective double blind trial of sixty patients undergoing knee arthroscopic procedures, patients were randomly assigned to three groups: Group R, receiving intra-articular ropivacaine (20 mL); Group D1 (18 mL ropivacaine, dexmedetomidine 1 µg/kg body weight); and Group D2 (18 mL ropivacaine, dexmedetomidine 2 µg/kg). RESULTS: Group D2 had significantly lower pain scores for the first 12 postoperative hours than Group D1 and Group R. Time to first analgesic requirement was longest in Group D2 (757.30 ± 207.68 min), followed by Group D1 (433.2 ± 54.3 min) and Group R (311.80 ± 61.56 min); these differences were significant (P < 0.05). Total analgesic requirement was significantly lower in Group D2 (82.50 ± 48.05 mg; P < 0.05). Intensity of pain was significantly less in Group D2 in the third (P < 0.01) and sixth hours (P < 0.05). CONCLUSION: Intra-articular dexmedetomidine (2 µg/kg) has superior analgesic efficacy, delayed the first postoperative requirement for analgesia and decreasing the need for postoperative analgesics with no major adverse effects.

Thrombotic popliteal block following simultaneous bi-cruciate single-stage arthroscopic reconstruction in a neglected multiligamentous knee injury in a smoker.

We report a case of neglected multiligamentous injury that developed a complete thrombotic popliteal artery block following arthroscopic surgery. A 56-year-old man, a farmer, presented with an 8-month history of instability of the right knee. Examination revealed ipsilateral anterior (ACL)/posterior cruciate ligament (PCL) injuries. MRI and diagnostic arthroscopy confirmed complete ACL/PCL tear. Single-stage arthroscopic ACL/PCL reconstruction was performed. Postsurgery, the operated limb appeared swollen, firm and cold, without sensation or toe movement. Angiogram revealed complete thrombotic block of left popliteal artery. Fogarty's catheterism was performed and distal vascularity re-established. At 28 months, the patient was back at work with good functional outcome. We failed to examine the patient preoperatively in spite of his advanced age, history of beedi smoking and tobacco use, and presence of feeble vascular pulsations with thickened skin over leg and foot. Thus, in multiligamentous injuries, patient selection and thorough detailed clinical examination are the keys to successful arthroscopic procedures.