Cath-KP, a novel peptide derived from frog skin, prevents oxidative stress damage in a Parkinson's disease model.

Parkinson's disease (PD) is a neurodegenerative condition that results in dyskinesia, with oxidative stress playing a pivotal role in its progression. Antioxidant peptides may thus present therapeutic potential for PD. In this study, a novel cathelicidin peptide (Cath-KP; GCSGRFCNLFNNRRPGRLTLIHRPGGDKRTSTGLIYV) was identified from the skin of the Asiatic painted frog ( Kaloula pulchra). Structural analysis using circular dichroism and homology modeling revealed a unique αßß conformation for Cath-KP. In vitro experiments, including free radical scavenging and ferric-reducing antioxidant analyses, confirmed its antioxidant properties. Using the 1-methyl-4-phenylpyridinium ion (MPP +)-induced dopamine cell line and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, Cath-KP was found to penetrate cells and reach deep brain tissues, resulting in improved MPP +-induced cell viability and reduced oxidative stress-induced damage by promoting antioxidant enzyme expression and alleviating mitochondrial and intracellular reactive oxygen species accumulation through Sirtuin-1 (Sirt1)/Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway activation. Both focal adhesion kinase (FAK) and p38 were also identified as regulatory elements. In the MPTP-induced PD mice, Cath-KP administration increased the number of tyrosine hydroxylase (TH)-positive neurons, restored TH content, and ameliorated dyskinesia. To the best of our knowledge, this study is the first to report on a cathelicidin peptide demonstrating potent antioxidant and neuroprotective properties in a PD model by targeting oxidative stress. These findings expand the known functions of cathelicidins, and hold promise for the development of therapeutic agents for PD.

Why some donors are more willing to donate platelets? ----a qualitative study on 25 regular platelet donors in Guangzhou, China.

BACKGROUND: Since 1998, China has gradually moved toward voluntary uncompensated blood donation. In some cities, the shortage of platelets has been noticeably severe. Mutual assistance that collects blood from one's family and social networks is a potential solution. The measure, however, turned out problematic. There are donors who choose to donate platelets over whole blood without compensations, and donate platelets directly to blood banks instead of via the mutual assistance system. This study explores reasons behind their choices qualitatively. METHODS: This report is based on data conducted from January to February 2018; 25 uncompensated regular platelet donors were interviewed. The blood component donation service team in Guangzhou facilitated the data collection process and referred prospectively eligible blood donors to our research team. The interviews took about 30 min to two hours to complete. The qualitative data were analyzed by using the software ATLAS.ti 8. RESULTS: Platelet donation takes a much long time than whole blood donation and requires complicated processes. It may also cause discomfort as the other blood components are returned to the body, causing physical and psychological distress due to worries about contamination. Thus, platelet donation tends to involve higher time and psychological costs than whole blood donation. Yet, it has short collection intervals that allows for more frequent donations, and urgency of a severer shortage than whole blood. Hence, regular platelet donors may feel higher significance in platelet donation than whole blood donation, with the belief that more lives would be saved. Some whole blood donors thus switched to become platelet donors. Mutual assistance blood donation was not chosen by the participants for platelet donation, because such donations may exert moral pressure to both the donors and recipients. Furthermore, "acquaintance" has been loosely defined; the system has sometimes been manipulated to become profit-making monetary transactions. It hence failed. CONCLUSIONS: The practice of platelet donation reinforces the understanding that blood donation is a gift giving process performed among strangers. A safe and sustainable voluntary blood supply can only be secured in the absence of monetary transactions and moral pressure.

Comparison of drugs facilitating endoscopy for patients with acute variceal bleeding: a systematic review and network meta-analysis.

BACKGROUND: We aimed to compare the efficacy of different drugs facilitating endoscopy in patients with acute variceal bleeding. METHODS: Databases were searched to identify randomized controlled trials which compared the efficacy of vasoactive drugs (vasopressin, terlipressin, octreotide, somatostatin) with placebo or each other. The primary outcomes were 6-week and 5-day mortality. Secondary outcomes were 5-day rebleeding, control of initial bleeding and adverse events. Pairwise and network meta-analysis were performed. RESULTS: We identified 14 RCTs involved 2,187 patients. Four drugs had comparable clinical efficacy in all involving outcomes, except for adverse events. However, we do exhibit a superiority when vasopressin (OR, 4.40; 95% CI: 1.04-19.57), terlipressin (OR, 4.58; 95% CI: 1.63-13.63), octreotide (OR, 5.79; 95% CI: 2.41-16.71) and somatostatin (OR, 5.15; 95% CI: 1.40-27.39) were compared to placebo respectively as for initial hemostasis. In addition, only octreotide was more effective than placebo in decreasing 5-day rebleeding (OR, 0.44; 95% CI: 0.22-0.90). Meanwhile, octreotide was shown to have the highest probability ranking the best to improve initial hemostasis (mean rank =1.8) and carries a lowest risk of adverse events (9.1%) and serious adverse events (0.0%) compared to other drugs. CONCLUSIONS: Balanced with curative effect and tolerability, octreotide may be the preferred vasoactive drug facilitating endoscopy.