α-amylase and α-glucosidase inhibition effects of Korean edible brown, green, and red seaweed extracts

The control of intestinal α-amylase and α-glucosidase is an effective therapeutic strategy for prevention of post-prandial hyperglycemia associated with diabetes mellitus. The objective of this study was to evaluate the anti-diabetes activities of Korean edible seaweed against α-amylase and α-glucosidase, two carbolytic enzymes involved in serum glucose regulation. Of the 41 species initially screened, Cladophora wrightiana var. minor, Eisenia bicyclis, Ecklonia cava, Ishige foliacea, and Ishige okamurae exhibited the strongest inhibitory activities from brown seaweeds. Asparagopsis taxiformis showed the strongest inhibitory effects from red seaweeds. The results of this study suggest that the crude brown seaweed extracts (C. wrightiana var. minor, E. bicyclis, E. cava, I. foliacea, and I. okamurae) and crude red seaweed extracts (A. taxiformis) may have beneficial effects suppressing the rise in postprandial hyperglycemia through the inhibition of α-amylase and α-glucosidase

Impact of Caveolin-1 Expression on the Prognosis of Transitional Cell Carcinoma of the Upper Urinary Tract

This study aimed to investigate the relationship of caveolin-1 expression with prognosis in patients with transitional cell carcinoma of the upper urinary tract (TCC-UUT). Formalin-fixed, paraffin-embedded tissue sections of TCC-UUT from 98 patients, who had undergone radical nephroureterectomy, were stained immunohistochemically using antibodies against caveolin-1. The expression pattern of caveolin-1 was compared with the clinicopathological variables. The caveolin-1 expression was significantly correlated with T stage (p<0.001) and grade (p=0.036). The survival rate of patients with caveolin-1 positive tumors was significantly lower than that of patients with caveolin-1 negative tumors (p<0.0001). The univariate analyses identified T stage, grade, and caveolin-1 expression as significant prognostic factors for cancer-specific survival, whereas the multivariate analyses indicated that T stage and caveolin-1 expression were independent prognostic factors. These results show that the increased expression of caveolin-1 is associated with tumor progression and poor prognosis in TCC-UUT, suggesting that caveolin-1 may play an important role in the progression of TCC-UUT

Anti-Inflammatory Potential of Carpomitra costata

Marine algae have valuable health and dietary benefits. The present study aimed to investigate whether an ethanol extract of Carpomitra costata (CCE) could inhibit the inflammatory response to LPS. CCE attenuated the production of proinflammatory mediators, such as prostaglandin E2 (PGE2) and nitric oxide (NO), by inhibiting inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-induced RAW264.7 macrophages. CCE also inhibited the expression of proinflammatory cytokines such as IL-1β, TNF-α, and IL-6. CCE suppressed the LPS-induced DNA-binding activity of (NF-κB) and activator protein-1 (AP-1). In addition, CCE attenuated the LPS-stimulated phosphorylation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK) and phosphatidylinositol 3′-kinase/Akt (PI3K/Akt). Functional aspects of the JNK and Akt signaling pathways were analyzed using specific inhibitors, which attenuated the LPS-induced production of proinflammatory cytokines, and NO and PGE2 expression by suppressing AP-1 and NF-κB activity. In particular, the AP-1 signaling pathway is not involved in the production of inflammatory cytokines, such as IL-6, TNF-α, and IL-1β. These results suggested that CCE might exert its anti-inflammatory action by downregulating transcriptional factors (NF-κB and AP-1) through JNK and Akt signaling pathways. The current study suggested that CCE might be a valuable candidate for the treatment of inflammatory disorders

Nogo-A regulates myogenesis via interacting with Filamin-C

Among the three isoforms encoded by Rtn4, Nogo-A has been intensely investigated as a central nervous system inhibitor. Although Nogo-A expression is increased in muscles of patients with amyotrophic lateral sclerosis, its role in muscle homeostasis and regeneration is not well elucidated. In this study, we discovered a significant increase in Nogo-A expression in various muscle-related pathological conditions. Nogo−/− mice displayed dystrophic muscle structure, dysregulated muscle regeneration following injury, and altered gene expression involving lipid storage and muscle cell differentiation. We hypothesized that increased Nogo-A levels might regulate muscle regeneration. Differentiating myoblasts exhibited Nogo-A upregulation and silencing Nogo-A abrogated myoblast differentiation. Nogo-A interacted with filamin-C, suggesting a role for Nogo-A in cytoskeletal arrangement during myogenesis. In conclusion, Nogo-A maintains muscle homeostasis and integrity, and pathologically altered Nogo-A expression mediates muscle regeneration, suggesting Nogo-A as a novel target for the treatment of myopathies in clinical settings. © 2021, The Author(s).1

Self-Supported Pt-Ni Mesostructures as Ultrastable Oxygen Reduction Reaction Electrocatalysts in Proton Exchange Membrane Fuel Cell

Improving the activity and durability of the cathode catalyst in proton exchange membrane fuel cells (PEMFCs) is of great importance for their commercialization. The most prevalent commercial catalysts are Pt-based nanoparticles, which are finely dispersed on high surface area carbon supports (Pt/C). During the fuel cell operation, considerable activity loss of Pt/C occurs because of corrosion of carbon support material, the dissolution of Pt, and the detachment of Pt nanoparticles from the carbon support. In this work, support-free 3D mesostructured spherical Pt-Ni alloy electrocatalysts (Meso-PtNi) of 100 nm in size were prepared by nanocasting mesoporous silica nanospheres (MSNs). Interestingly, hightemperature annealing at 600 ??C afforded the formation of PtNi intermetallic ordered phase while reduction at 300 ??C generated disordered Pt-Ni alloy phase. Electrocatalytic activity and stability of Meso-PtNi for the oxygen reduction reaction (ORR) was investigated in 0.1 M HClO4. Meso-PtNi catalysts showed enhanced performance in ORR measurement compared to Pt/C, Pt black, and Meso-Pt. Importantly, Meso-PtNi containing intermetallic phase exhibited better activity than disordered alloy structure. An accelerated degrading test (ADT) was conducted according to the US Department of Energy???s protocol. Meso-PtNi showed superior stability as compared to the commercial Pt/C and Pt black catalysts, up to 30,000 potential cycling. Particularly, the Meso-PtNi with intermetallic phase showed a remarkable stability. It was found that Meso-PtNi was activated during the early stage of ADT, and retained its increased ORR activity up to 50,000 cycling. We fabricated membrane electrode assembly based on the intermetallic Meso-PtNi cathode, and achieved the excellent single cell performance in PEMFC

Protective effects of alginate-free residue of sea tangle against hyperlipidemic and oxidant activities in rats

Abstract The antihyperlipidemic and antioxidant activities of dietary supplementation of sea tangle from Goseong and the alginate-free residue of sea tangle were investigated in Sprague Dawley rats treated with a high-fat diet, streptozotocin, poloxamer 407, and bromobenzene. The alginate-free residue of Goseong sea tangle induced a significant reduction in triglycerides and total cholesterol levels, as well as a significant increase in high-density lipoprotein cholesterol levels. Alginate-free Goseong sea tangle residue reduced the activities of the phase I enzymes aminopyrine N-demethylase and aniline hydroxylase, which had been increased by intraperitoneal injection of bromobenzene. Pretreatment with Goseong sea tangle residue prevented a bromobenzene-induced decrease in epoxide hydrolase activity. Bromobenzene reduced hepatic glutathione content and increased hepatic lipid peroxide levels. Pretreatment with alginate-free Goseong sea tangle residue prevented lipid peroxidation induced by bromobenzene, but pretreatment with Goseong sea tangle did not. These results suggest that Goseong sea tangle residue exerted antihyperlipidemic and antioxidant activities that were higher than those induced by alginate-containing sea tangle. Therefore, the alginate-free residue may contain physiologically unknown active components, other than alginic acid, which may potentially be used to prevent hyperlipidemic atherosclerosis

Ultra-Low Pt Decorated Porphyrinic Carbon Based Hybrid Electrocatalysts for Oxygen Reduction Reaction

As the fuel cell market has been growing, the price competitiveness of polymer electrolyte fuel cell (PEFC) became the most important factor for its commercialization. In particular, the production of membrane-electrode assembly (MEA) consisting of Pt-based electrocatalyst is a critical hurdle for the cost reduction of PEFCs. Therefore, many researchers have veen focusing on the development of cost effective electrocatalysts such as non-precious metal based catalysts (NPMCs) or low content platinum based catalysts to minimize Pt loading by morphological and structural tunings with inexpensive transition metals. Recently, we reported the M-N doped ordered mesoporous porphyrinic carbon (M-OMPC, M=Fe, Co) which showed a comparable ORR activity to that of Pt/C in an acid medium. However, an inferior MEA performance of M-OMPC is a practical barrier because of high mass transport resistance and electrical resistance, which mainly comes from the thicker electrode of M-OMPC. In this study, we proposed a new approach for enhanced ORR activity as well as reduction of noble metal loading content via adding a trace of platinum nanoclusters on M-OMPC. The Pt/M-OMPC (Pt~5 wt%) hybrid catalyst showed an increased Pt based mass activity and specific activity by a factor of 7, compared to that of Pt/C (5 wt%) at 0.85 V RHE

Assessing the degradation pattern and mechanism of membranes in polymer electrolyte membrane fuel cells using open-circuit voltage hold and humidity cycle test protocols

As the degradation of polymer electrolyte membranes (PEMs) shows catastrophic failures with pinholes and cracks, studies on PEM degradation are essential to improve the reliability and lifetime of polymer electrolyte membrane fuel cell (PEMFC) membrane electrode assemblies (MEAs). However, the investigation of the degradation patterns and understanding of the degradation mechanisms of PEMs are still very limited at the PEMFC MEA level. Herein, open-circuit voltage (OCV) hold (chemical degradation) and humidity cycle test (mechanical degradation) protocols are applied to assess the durability of membrane components of PEMFC MEAs. OCV hold test is conducted at low relative humidity (30%) and OCV condition for 540 h. Humidity cycle test (5000 cycles) is carried out under repeating low (0%) and high (150%) relative humidities. We investigate degradation patterns and mechanisms of PEMs for MEAs after OCV hold and humidity cycle tests using various electrochemical and physicochemical analyses tools. The present study, by providing fundamental understanding of major degradation mechanisms, generates scientific information regarding design tools for the fabrication of highly durable PEMs. Additionally, this study, through accelerated degradation tests, can provide baseline information regarding the durability and lifetime of PEMs by statistically analyzing the deterioration pattern of MEAs