Antibacterial and Anticancer Activities of Pleurocidin-Amide, a Potent Marine Antimicrobial Peptide Derived from Winter Flounder, Pleuronectes americanus.

The extensive use of conventional antibiotics has led to the growing emergence of many resistant strains of pathogenic bacteria. Evidence suggests that cationic antimicrobial peptides (AMPs) have the greatest potential to serve as traditional antibiotic substitutes. Recent studies have also reported that certain AMPs have selective toxicity toward various types of cancer cells. The electrostatic attraction between the negatively charged membrane components and AMPs is believed to play a crucial role in the disruption of bacterial and cancer cell membranes. In the current study, we used a potent AMP called Pleurocidin (Ple) derived from winter flounder Pleuronectes americanus and its C-terminal-amidated derivative Pleurocidin-amide (Ple-a), and evaluated their antibacterial and anticancer activities. Our results indicated that both Ple and Ple-a exhibited significant antibacterial activity against a broad spectrum of Gram-positive and Gram-negative bacteria, especially marine pathogens, with MIC values ranging from 0.25 to 32 µg/mL. These peptides are also potent against several multidrug-resistant (MDR) bacterial strains, with MIC values ranging from 2 to 256 µg/mL. When used in combination with certain antibiotics, they exhibited a synergistic effect against MDR E. coli. Ple and Ple-a also showed notable cytotoxicity toward various cancer cell lines, with IC50 values ranging from 11 to 340 µM, while normal mouse fibroblast 3T3 cells were less susceptible to these peptides. Ple-a was then selected to study its anticancer mechanism toward A549 human lung adenocarcinoma cells. Western blot analysis and confocal microscopy showed that Ple-a could inhibit autophagy of A549 cells, and induce apoptosis 48 h after treatment. Our findings provided support for the future application of Ple-a as potential therapeutic agent for bacterial infections and cancer treatment.

Constant Daily Exercise to Keep the Doctor Away: A Study of Adherence to Physical Exercise Using a Gym in Individuals Older Than 55 Years.

The purpose of this study was to examine the role of using a gym as a mechanism for adherence to regular physical exercise among individuals with aged 55 and over. This was a grounded theory research design. Data were collected from face-to-face interviews and observations among 15 people who attended the gym regularly and then analysed via content analysis. Three categories emerged from the present study regarding the adherence to regular physical exercise: (1) meaningful starting points, (2) reinforcement by motivators, and (3) adherence through positive changes. Results of this study can help health policymakers, managers of gyms/fitness centres, and gym instructors to design and implement programs.

Doses of renin-angiotensin system inhibitors but not beta-blockers predict outcome after ST-elevation myocardial infarction.

Objectives: In patients with ST-elevation myocardial infarction (STEMI), it is not clear whether low-dose renin-angiotensin system inhibitors and beta-blockers can result in the same benefits achievable with higher target doses. This observational study aims to investigate whether higher doses of angiotensin converting enzyme inhibitors (ACEI)/angiotensin II receptor blockers (ARB) and beta-blockers can improve outcomes in patients with STEMI. Methods: We recorded daily doses of ACEI, ARB, and beta-blockers in 331 patients with STEMI. Echocardiographic studies were performed at baseline and were repeated 6 months later. Clinical events, including all-cause death and heart failure, were followed for 2 years. Results: Patients receiving high-dose ACEI/ARB had less increase in left ventricular end-diastolic volume index (LVEDVI) at 6 months. In multivariable linear regression model, ACEI/ARB dose or beta-blocker dose was not an independent predictor of increase in LVEDVI at 6 months. Kaplan-Meier survival curves showed that doses of ACEI/ARB (p = 0.003) and beta-blockers (p = 0.027) were significant predictors of death and heart failure. In multivariable Cox regression analysis, independent predictors of all-cause death and heart failure were diabetes mellitus (p = 0.001), left ventricular ejection fraction (p = 0.026), and ACEI/ARB dose (p = 0.025). Beta-blockers dose was not a predictor of clinical events in multivariable analysis (p = 0.413). Conclusion: High-dose ACEI/ARB, but not beta-blocker, was associated with lower rate of all-cause death and heart failure in patients with STEMI.