A novel method for conjugating the terminal amine of peptide ligands to cholesterol: synthesis iRGD-cholesterol.

AIM: Conventional conjugation reactions often involve the use of activated PEG as a linker, but concerns about PEG-mediated reduction in intracellular delivery and enhanced immunogenicity have generated interest in developing methods that eliminate the need for a PEG linker. MATERIALS & METHODS: Reaction conditions were identified that specifically couples the terminal amine of a cyclic iRGD peptide (CRGDRGPDC) to the hydroxyl moiety of cholesterol through a short carbamate linker. RESULTS & CONCLUSION: Using this method for synthesizing iRGD-cholesterol, peptide ligands can be incorporated into lipid-based delivery systems, thereby eliminating concerns about adverse reactions to PEG. Toxicity and stability data indicate low toxicity and adequate serum stability at low ligand levels.

Peer Evaluation Instrument Development, Administration, and Assessment in a Team-based Learning Curriculum.

Objective. To design and implement an instrument capable of providing students with valuable peer feedback on team behaviors and to provide results of the administration of the instrument. Methods. A three-part instrument was designed that requires teammate rankings with justification on attributes aligned with school outcomes and team functioning, reporting of student behaviors, and provision of feedback on the value of peer contributions to their team. Score results after three years of administration were analyzed. Results. Six evaluations per year were completed by members of four different professional classes over a three-year time period. Mean scores increased slightly as students progressed through the program. Students were able to differentially score peers on attributes and behaviors. Conclusion. The peer evaluation instrument presented here provides formative and summative feedback through qualitative and quantitative scores that allow students to acknowledge differential contributions of individual team members.

Banned and discouraged-use ingredients found in weight loss supplements.

OBJECTIVES: To identify banned and discouraged-use ingredients, such as ephedra, 1,3-dimethylamylamine, and beta-methyl-phenylethylamine, in readily available weight loss dietary supplements within a 10-mile radius of Regis University. METHODS: A list of banned and discouraged-use ingredients was compiled with the use of the Food and Drug Administration (FDA) dietary supplement website which provides information on supplement ingredients that are no longer legal or are advised against owing to adverse event reporting. Investigators visited all retail outlet stores within a 10-mile radius of Regis University in Denver, Colorado. Retail chains were not duplicated and only one of each chain was evaluated. RESULTS: A total of 51 weight loss supplement products from retail stores were found with banned or discouraged-use substances listed on their labels. At least one banned ingredient was found to be listed on the product labels in 17 of the 51 studied supplements (33%). At least one discouraged-use ingredient was found in 46 of the 51 products (90%). Retail outlet stores dedicated to supplements and sports nutrition alone were found to have the greatest number of weight loss supplements that included banned and discouraged-use ingredients. CONCLUSION: The FDA has taken action to remove some weight loss supplements from the market that contain banned ingredients. Unfortunately, based on the findings of this study, it is evident that products containing these ingredients remain on the market today.

Ceftolozane/Tazobactam: A New Cephalosporin and ß-Lactamase Inhibitor Combination.

OBJECTIVE: To review the chemistry, pharmacology, microbiology, pharmacokinetics, pharmacodynamics, clinical efficacy, tolerability, dosage, and administration of ceftolozane/tazobactam, a new antipseudomonal cephalosporin combined with a well-established ß-lactamase inhibitor. DATA SOURCES: A literature search through clinicaltrials.gov and PubMed was conducted (January 2007-May 2015) using the search terms ceftolozane, ceftolozane/tazobactam, FR264205, CXA-101/tazobactam, and CXA-201. References from retrieved articles and abstracts presented at recent meetings were reviewed to identify additional material. The prescribing information was also reviewed. STUDY SELECTION AND DATA EXTRACTION: Preclinical data as well as phase 1, 2, and 3 studies published in English were evaluated. DATA SYNTHESIS: Ceftolozane/tazobactam displays enhanced potency against Pseudomonas aeruginosa in vitro. Clinical trials have shown that ceftolozane/tazobactam is noninferior to levofloxacin for the treatment of complicated urinary tract infections (76.9% vs 68.4%, 95% CI = 2.3-14.6) and when used in combination with metronidazole is noninferior to meropenem for the treatment of complicated intra-abdominal infections (83% vs 87.3%, 95% CI = -8.91 to 0.54). An alternate antibiotic should be considered in patients who have a severe ß-lactam allergy or an estimated creatinine clearance between 30 and 50 mL/min. Ceftolozane/tazobactam is well tolerated, with few drug interactions and no effects on the cytochrome P450 system. CONCLUSIONS: In an era of increasing resistance to antimicrobials, ceftolozane/tazobactam provides clinicians with an additional treatment option for infections caused by multidrug-resistant Gram-negative organisms, including extended-spectrum ß-lactamase-producing bacteria and Pseudomonas aeruginosa.

HCB11(CF3)(n)F(11-n)-: inert anions with high anodic oxidation potentials.

Cs salts of four of the title anions were prepared by fluorination of salts of partly methylated (n = 11, 10) or partly methylated and partly iodinated (n = 6, 5) CB(11)H(12)(-) anions. The CH vertex is acidic, and in the unhindered anion with n = 6 it has been alkylated. Neat Cs(+)[1-H-CB(11)(CF(3))(11)](-) is as treacherously explosive as Cs(+)[CB(11)(CF(3))(12)](-), but no explosions occurred with the salts of the other three anions. BL3YP/6-31G* gas-phase electron detachment energies of the title anions are remarkably high, 5-8 eV. Treated with NiF(3)(+) in anhydrous liquid HF at -60 °C, anions with n = 11 or 10 resist oxidation, whereas anions with n = 6 or 5 are converted to colored EPR-active species, presumably the neutral radicals [HCB(11)(CF(3))(n)F(11-n)](•). These are stable for hours at -60 °C after extraction into cold perfluorohexane or perfluorotri-n-butylamine solutions. On warming to -20 °C in a Teflon or quartz tube, the color and EPR activity disappear, and the original anions are recovered nearly quantitatively, suggesting that the radicals oxidize the solvent.

The sixteen CB(11)H(n)Me(12-n)(-) anions with fivefold substitution symmetry: anodic oxidation and electronic structure.

The 15 symmetrically methylated derivatives of the CB11H12(-) anion (1a) have been synthesized and found to vary greatly in ease of oxidation. Cyclic voltammetry in liquid SO2 yielded fully reversible oxidation potentials for five of those that have no adjacent unsubstituted vertices in positions 7-12; three others showed some indication of reversibility. The anions 1a-16a and the Jahn-Teller distorted neutral radicals 1r-16r have been characterized by ab initio and density functional theory calculations. In the state average CASSCF(13,12)/6-31+G* approximation, the ground state potential energy surface of 1r contains five symmetry-related pairs of minima. The computational results account for the reversible redox potentials very well when the solvent is included explicitly (RI-DFT(BP)/TZVP, COSMO). For display and for a semiquantitative understanding of methyl substituent effects in terms of perturbation theory, the molecular orbitals of 1a have been expressed in the symmetry-adapted cluster basis. The results serve as an underpinning for a set of additive empirical increments for redox potential prediction. Relative to the usual hydrogen standard, a single methyl group facilitates oxidation by approximately 50, 70, 70, and 10 mV in positions 1, 2, 7, and 12, respectively. This electron donor effect on the redox potential is due to a contribution, whereas those of (inductive and direct field) type are negligible.

CB11Me11 boronium ylides: carba-closo-dodecaboranes with a naked boron vertex.

In pentane solution, 2 equiv of the icosahedral CB(11)Me(12)(*) radical cleaves the Si-Si bond of hexaalkyldisilanes by boron to silicon methyl transfer with formation of 2 equiv of methyltrialkylsilanes. The loss of a methyl radical converts the CB(11)Me(12)(*) radical into an internally charge-compensated "boronium ylide" CB(11)Me(11) with a naked vertex, which can be formally viewed as a deprotonated hypercloso carborane. It has been isolated as an air-sensitive solid, stable only below approximately -60 degrees C. The naked vertex appears to be in position 12 since the material reacts instantaneously with alcohols and ethers to form the 12-alkoxy anions 12-CB(11)Me(11)OR. It reacts with many other nucleophiles to yield more complex mixtures containing similar products. DFT calculations for the four CB(11)Me(11) isomers give closed-shell ground-state electronic structures. For the isomer with naked vertex 12, a DFT computational search failed to reveal any skeletal dimers, apparently due to excessive methyl-methyl repulsions, and only a cyclic dimer bound through weak interactions of one of the 7-methyl hydrogen atoms on each cage with the empty exocyclic orbitals on B12 of the other cage was found. Natural hybrid orbital populations suggest that the three possible isomers of monomeric boronium ylides are close to true singlet ylides, with triplet states approximately 50 kcal/mol higher. The calculated electronic structure of the carbonium ylide is close to a singlet carbene, with a triplet state approximately 16 kcal/mol higher. An attempted preparation of Me(3)C(+)CB(11)Me(12)(-) yielded neopentane and products consistent with a sequential loss of methyl groups from the carborane cage with a transient formation of similar boronium ylides. Probable mechanisms of these methyl transfer reactions are considered, and the possibly quite general role of "ylide" structures in Lewis acid induced substitution reactions on the boron vertices of carboranes and boranes is noted.