Aim: Comparisons between the resting full-cycle ratio (RFR), a new physiological resting index, and fractional flow reserve (FFR) in terms of prognostic value are limited. We aimed to identify the prognostic value of concordance between RFR and FFR and to determine the stability of measured RFR. Methods and Results: We measured FFR and RFR in 161 coronary arteries of 119 patients and classified the data using known cutoffs for FFR (≤0.80) and RFR (≤0.89) into groups; high FFR and high RFR (high FFR/low RFR) group, high FFR and low RFR (high FFR/low RFR) group, low FFR and high RFR (low FFR/high RFR) group, and low FFR and low RFR (low FFR/low RFR) group. The concordance rates in these groups were 42.2% (68/161), 4.4% (7/161), 14.3% (23/161), and 39.1% (63/161), respectively. The concordance between FFR and RFR was 81.4%. The prevalence of females was significantly higher, values for hemoglobin values were significantly lower, and average E/E 0 (an index of left ventricular (LV) diastolic function by echocardiography) was significantly higher in high FFR/low RFR group than in low FFR/high RFR group (p = .008, .050, and .028, respectively). Conclusions: The RFR and FFR values consistently agreed. Female, anemia, and LV diastolic dysfunction may be related to the difference of discordance between high FFR/low RFR and low FFR/high RFR.

A chiral cyclic α,α-disubstituted α-amino acid, (S)-(−)-cucurbitine, which has a pyrrolidine ring with a chiral center at the α-position, was synthesized, and its homopeptides were prepared. (S)-(−)-Cucurbitine homopeptides with a Boc-protecting group formed helical structures with slight control of the helical screw sense to the left-handed form. The state of the pyrrolidine ring in (S)-(−)-cucurbitine was important for the control of the helical structures and helical screw sense of its homopeptides.

Graphical AbstractTo create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered.Peptide foldamers composed of six-membered ring α,α-disubstituted α-amino acids with two changeable chiral acetal moieties IntroductionConformational freedom-restricted oligopeptides have attracted the attention of organic, peptide, and medicinal chemists because they are capable of developing peptide organo-catalysts for asymmetric reactions and are also drug candidates derived from biologically active natural peptides.1 α,α-Disubstituted α-amino acids (dAAs) have been used to restrict the conformational freedom of their peptides. 2Oligopeptides incorporating α-aminoisobutyric acid (Aib; αMeAla) have been shown to preferentially form 310-/α-helical structures, whereas peptides having α-ethylated dAAs, such as diethylglycine and (S)-butylethylglycine, are more likely to assume fully planar conformations.3 Differences in secondary structures (helix and planar conformations) are determined by the peptide-backbone torsion angles φ (C'-N-Cα-C') and ψ (N-Cα-C'-N). For example, the ideal right-handed (P) 310-helix has φ −60° and ψ −30° torsion angles, the right-handed (P) α-helix has φ −57° and ψ −47°, and the fully planar conformation has φ 180° and ψ 180°. The patterns of intramolecular hydrogen bonds also differ in these secondary structures. For example, the 310-helix forms an intramolecular hydrogen bond of the N(i+3)-H···O(i)=C(i) i←i+3 type, whereas the α-helix forms an intramolecular hydrogen bond of the N(i+4)-Moreover, the fully planar conformation forms an intramolecular hydrogen bond of the C5---- * Corresponding author. Tel/fax: +81 95 819 2423; e-mail: matanaka@nagasaki-u.ac.jpBy selecting appropriate dAAs, these secondary structures are partially controlled. However, the preferential conformations of known dAAs are limited to those of helix and planar conformations. Thus, the development of new dAAs with different conformational preferences is greatly desired.One such dAA may be the achiral O,O-isopropylidene-α-hydroxymethylserine {Hms(Ipr)} reported by Toniolo, Leplawy, and co-workers. Hms(Ipr) peptides formed destabilized 310-helical structures, in which hydrogen bonds were detected between peptide main-chain NH and side-chain acetonide -O-.We recently synthesized six-membered ring dAAs with a changeable chiral acetal moiety as well as the preferred secondary structures of their peptides.5 These findings prompted us to change the position of the acetal moiety on the cyclohexane ring and increase the number of acetal moieties on the cyclic amino acid. We designed six-membered ring dAAs with two chiral acetal moieties {(R,R)- Chiral cyclic α,α-disubstituted α-amino acids with four chiral centers at their acetal moieties were synthesized. An X-ray crystallographic analysis of homo-chiral tripeptide with (2R,3R)-butane-2,3-diol acetal moieties revealed that the tripeptide formed both (P) and (M) helical structures, and all peptide main-chain N(i)-H...

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The relationship between chiral centers and the helical-screw control of their peptides has already been reported, but it has yet to be elucidated in detail. A chiral four-membered ring α,α-disubstituted α-amino acid with a (R,R)-butane-2,3-diol acetal moiety at the γ-position, but no α-chiral carbon, was synthesized. X-ray crystallographic analysis unambiguously revealed that its homo-chiral heptapeptide formed right-handed (P) and left-handed (M) 3 -helical structures at a ratio of 1:1. They appeared to be enantiomeric at the peptide backbone, but diastereomeric with fourteen (R)-configuration chiral centers. Conformational analyses of homopeptides in solution also indicated that diastereomeric (P) and (M) helices existed at approximately equal amounts, with a slight preference toward right-handedness, and they quickly interchanged at room temperature. The circumstances of chiral centers are important for the control of their helical-screw direction.