Equivalence in Color-coded Duplex Sonography Parameters before Complex Microsurgery.

Background: Color-coded duplex sonography (CCDS) is a widely proposed noninvasive diagnostic tool in microsurgery. CCDS has been applied to lower extremity salvage cases to define appropriate blood flow velocity criteria for achieving arterial success in diabetic foot and complex microsurgery cases. This study aimed to compare the success ratio of free flaps when using CCDS versus cases where CCDS was not used. Methods: We included complex microsurgery cases from 2019 to 2021. These cases were subsequently categorized into two groups: group A consisted of cases where CCDS parameters were applied, whereas group B comprised cases where CCDS was not performed at all. Results: The study encompassed 14 cases (11 men and three women). The age range varied from 23 to 62 years, with an average age of 42. Using CCDS analysis and planning demonstrated improved outcomes in comparison with cases where CCDS was not performed, albeit without statistical significance (P = 0.064). Conclusions: The application of CCDS proves to be beneficial in the realm of microsurgery. Although not achieving statistical significance, our data imply that CCDS utilization holds promise for enhancing microsurgical procedures.

Synthesis of Mixed α/ß2,2-Peptides by Site-Selective Ring-Opening of Cyclic Quaternary Sulfamidates.

A method for site- and stereoselective peptide modification using a cyclic sulfamidate scaffold containing peptides is described. A peptide synthesis strategy allowing the rapid generation of mixed α/ß-peptides incorporating a sulfamidate residue, derived from 2-methylisoserine, has been generalized. The unique electrophilic nature of this scaffold for nucleophilic substitution at a quaternary center with total inversion of its configuration, which was demonstrated computationally, allows for site-selective conjugation with various nucleophiles, such as anomeric thiocarbohydrates and pyridines. This strategy provides rapid access to complex thioglyco-α/ß-conjugates and charged α/ß-peptides.

Synthesis and conformational analysis of hybrid α/ß-dipeptides incorporating S-glycosyl-ß(2,2)-amino acids.

We synthesized and carried out the conformational analysis of several hybrid dipeptides consisting of an α-amino acid attached to a quaternary glyco-ß-amino acid. In particular, we combined a S-glycosylated ß(2,2)-amino acid and two different types of α-amino acid, namely, aliphatic (alanine) and aromatic (phenylalanine and tryptophan) in the sequence of hybrid α/ß-dipeptides. The key step in the synthesis involved the ring-opening reaction of a chiral cyclic sulfamidate, inserted in the peptidic sequence, with a sulfur-containing nucleophile by using 1-thio-ß-D-glucopyranose derivatives. This reaction of glycosylation occurred with inversion of configuration at the quaternary center. The conformational behavior in aqueous solution of the peptide backbone and the glycosidic linkage for all synthesized hybrid glycopeptides was analyzed by using a protocol that combined NMR experiments and molecular dynamics with time-averaged restraints (MD-tar). Interestingly, the presence of the sulfur heteroatom at the quaternary center of the ß-amino acid induced θ torsional angles close to 180° (anti). Notably, this value changed to 60° (gauche) when the peptidic sequence displayed aromatic α-amino acids due to the presence of CH-π interactions between the phenyl or indole ring and the methyl groups of the ß-amino acid unit.