Pep-7

Porphyromonas gingivalis, the major etiologic agent of chronic periodontitis, produces a broad spectrum of virulence factors, including outer membrane vesicles, lipopolysaccharides, hemolysins and proteinases. Antimicrobial peptides (AMPs) including bacteriocins have been found to inhibit the growth of P. gingivalis; however, these peptides are relatively large molecules. Hence, it is difficult to synthesize them by a scale-up production. Therefore, this study aimed to synthesize a shorter AMP that was still active against P. gingivalis. A peptide that contained three cationic amino acids (Arg, His and Lys), two anionic amino acids (Glu and Asp), hydrophobic amino acids residues (Leu, Ile, Val, Ala and Pro) and hydrophilic residues (Ser and Gly) was obtained and named Pep-7. Its bioactivity and stability were tested after various treatments. The mechanism of action of Pep-7 and its toxicity to human red blood cells were investigated. The Pep-7 inhibited two pathogenic P. gingivalis ATCC 33277 and P. gingivalis ATCC 53978 (wp50) strains at a minimum bactericidal concentration (MBC) of 1.7 µM, but was ineffective against other oral microorganisms (P. intermedia, Tannerella forsythensis, Streptococcus salivarius and Streptococcus sanguinis). From transmission electron microscopy studies, Pep-7 caused pore formation at the poles of the cytoplasmic membranes of P. gingivalis. A concentration of Pep-7 at four times that of its MBC induced some hemolysis but only at 0.3%. The Pep-7 was heat stable under pressure (autoclave at 110 and 121 °C) and possessed activity over a pH range of 6.8-8.5. It was not toxic to periodontal cells over a range of 70.8-4.4 μM and did not induce toxic pro-inflammatory cytokines. The Pep-7 showed selective activity against Porphyromonas sp. by altering the permeability barriers of P. gingivalis. The Pep-7 was not mutagenic in vitro. This work highlighted the potential for the use of this synthetic Pep-7 against P. gingivalis.

The objective of the study was to investigate the effect of positive expiratory pressure (PEP) and Flutter on expectoration in cystic fibrosis (CF) patients. Data was gathered through 260 treatments with 10 patients (5 female; 19.2 years; BMI: 18.0). Two methods were used alternately, first the patients started with Flutter and proceeded with PEP, and the next occasion they exercised in the reverse order, starting with PEP then continuing with Flutter. During each phase, 5 sets of 10 exhalations were performed. Sputum weight was measured after the use of the first device, and at the end of the treatment. During sessions starting with Flutter 4.0 ± 4.0 g sputum was expectorated, continuing with PEP, an additional 5.2 ± 5.0 g was produced, altogether 9.2 ± 8.2 g. At sessions starting with PEP 7.4 ± 3.7 g was expectorated, continuing with Flutter an additional 0.8 ± 1.4 g, that is 8.2 ± 4.1 g. Comparing the two devices by themselves, PEP proved to be significantly more efficient then Flutter. Comparing the two treatment types it is statistically not proven, which one is preferable using both devices. Conclusively, PEP is significantly more efficient than the Flutter in sputum expectoration among CF patients. The Flutter is a useful supplementary device.

An electrophoretically detectable variant of peptidase-7 in Mus musculus has been found and used to locate the structural gene, Pep-7, on chromosome 5. Gene order and recombination frequencies are estimated as Pep-7, 3.5 +/- 2.0 Rw 8.8 +/- 2.2 go 20.0 +/- 4.6 bf.