Evaluation of the antioxidant and antityrosinase activities of three extracts from Pleurotus nebrodensis fruiting bodies

Pleurotus nebrodensis has been widely used for nutritional and medicinal purposes. The aim of the present study was to evaluate the antioxidant activities and tyrosinase inhibitory effects on the fruiting bodies of P. nebrodensis extracted with acetone, methanol and hot water. The antioxidant activities were performed on - carotene-linoleic acid, reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferrous ions chelating abilities and xanthine oxidase inhibitory activity. In addition to this, phenolic compounds were also detected. The acetonic and methanolic extracts of P. nebrodensis showed the strongest -carotene-linoleic acid inhibition as compare to hot water extract. At 8 mg/ml, the acetonic extract showed a high reducing power of 1.86. The scavenging activity on DPPH radicals, the acetonic and methanolic extracts were effective than that of hot water extract. At lower concentrations, chelating effect of tested mushroom was significantly effective as compare to positive control. Gallic acid, protocatechuic acid, chlorogenic acid, ferulic acid, naringenin, hesperetin, formononetin and biochanin-A were detected from acetonitrile and hydrochloric acid solvent extract. The xanthine oxidase and tyrosinase inhibitory activities of the acetonic, methanolic and hot water extracts increased with increase of concentration. This study suggests that fruiting bodies of P. nebrodensis can potentially be used as a readily accessible source of natural antioxidants.Key words: Antioxidant, phenolic compounds, Pleurotus nebrodensis, tyrosinase inhibition, xanthine oxidase

X-knife stereotactic radiosurgery for cerebral AVM: Queen Mary Hospital experience

Meeting Theme: Degenerative Lumbar SpineOral-Poster Presentation 1INTRODUCTION: This is a retrospective review of the effectiveness, safety, complications of LINAC based X-knife stereotactic radiosurgery for the treatment of cerebral AVM in Queen Mary Hospital, Hong Kong. METHODS: Retrospective search through medical records of a single institution. From 2003-2013, all patients who received X-knife stereotactic radiosurgery for cerebral AVM were included. Demographics, presenting symptoms, size of AVM, Spetzler-Martin grading, dosages, complications, follow-up …published_or_final_versio

Sex-specific associations of adiposity with cardiometabolic traits in the UK: A multi-life stage cohort study with repeat metabolomics

Background Sex differences in cardiometabolic disease risk are commonly observed across the life course but are poorly understood and may be due to different associations of adiposity with cardiometabolic risk in females and males. We examined whether adiposity is differently associated with cardiometabolic trait levels in females and males at 3 different life stages. Methods and findings Data were from 2 generations (offspring, Generation 1 [G1] born in 1991/1992 and their parents, Generation 0 [G0]) of a United Kingdom population-based birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC). Follow-up continues on the cohort; data up to 25 y after recruitment to the study are included in this analysis. Body mass index (BMI) and total fat mass from dual-energy X-ray absorptiometry (DXA) were measured at mean age 9 y, 15 y, and 18 y in G1. Waist circumference was measured at 9 y and 15 y in G1. Concentrations of 148 cardiometabolic traits quantified using nuclear magnetic resonance spectroscopy were measured at 15 y, 18 y, and 25 y in G1. In G0, all 3 adiposity measures and the same 148 traits were available at 50 y. Using linear regression models, sex-specific associations of adiposity measures at each time point (9 y, 15 y, and 18 y) with cardiometabolic traits 3 to 6 y later were examined in G1. In G0, sex-specific associations of adiposity measures and cardiometabolic traits were examined cross-sectionally at 50 y. A total of 3,081 G1 and 4,887 G0 participants contributed to analyses. BMI was more strongly associated with key atherogenic traits in males compared with females at younger ages (15 y to 25 y), and associations were more similar between the sexes or stronger in females at 50 y, particularly for apolipoprotein B-containing lipoprotein particles and lipid concentrations. For example, a 1 standard deviation (SD) (3.8 kg/m2) higher BMI at 18 y was associated with 0.36 SD (95% confidence interval [CI] = 0.20, 0.52) higher concentrations of extremely large very-low-density lipoprotein (VLDL) particles at 25 y in males compared with 0.15 SD (95% CI = 0.09, 0.21) in females, P value for sex difference = 0.02. By contrast, at 50 y, a 1 SD (4.8 kg/m2) higher BMI was associated with 0.33 SD (95% CI = 0.25, 0.42) and 0.30 SD (95% CI = 0.26, 0.33) higher concentrations of extremely large VLDL particles in males and females, respectively, P value for sex difference = 0.42. Sex-specific associations of DXA-measured fat mass and waist circumference with cardiometabolic traits were similar to findings for BMI and cardiometabolic traits at each age. The main limitation of this work is its observational nature, and replication in independent cohorts using methods that can infer causality is required. Conclusions The results of this study suggest that associations of adiposity with adverse cardiometabolic risk begin earlier in the life course among males compared with females and are stronger until midlife, particularly for key atherogenic lipids. Adolescent and young adult males may therefore be high priority targets for obesity prevention efforts

Wirelessly triggered bioactive molecule delivery from degradable electroactive polymer films

The development of stimuli‐responsive drug delivery systems offers significant opportunities for innovations in industry. It is possible to produce polymer‐based drug delivery devices enabling spatiotemporal control of the release of the drug triggered by an electrical stimulus. Here we describe the development of a wireless controller for drug delivery from conductive/electroactive polymer‐based biomaterials and demonstrate its function in vitro . The wireless polymer conduction controller device uses very low power, operating at 2.4 GHz, and has a supply voltage controller circuit which controls electrical stimulation voltage levels. The computer graphical user interface program communicates with the controller device, and it receives device information, device status and temperature data from the controller device. The prototype of the wireless controller system can trigger the delivery of a drug, dexamethasone phosphate, from a matrix of degradable electroactive polymers. Furthermore, we introduce the application of in silico toxicity screening as a potentially useful method to facilitate the design of non‐toxic degradable electroactive polymers for a multitude of biotechnological applications, addressing one of the key commercial challenges to biomaterial development, in accordance with ‘safe by design’ principles

Assessment of allelopathic potential of selected medicinal plants of Pakistan

Inula falconeri, Inula koelzii, Lactuca dissecta and Anthemis nobilis were collected from Himalaya and Hindukush ranges of Pakistan and their allelopathic effect was studied through Sandwich and Homogenated Sandwich methods. The study also aimed at analyzing whether method andconcentration can affect the overall results. The results showed that method has no significant value; however, concentration of leaf leachates has highly significant value for exploring the inhibition or stimulation pattern of the plant species

Large-scale analysis of antigenic diversity of T-cell epitopes in dengue virus

BACKGROUND: Antigenic diversity in dengue virus strains has been studied, but large-scale and detailed systematic analyses have not been reported. In this study, we report a bioinformatics method for analyzing viral antigenic diversity in the context of T-cell mediated immune responses. We applied this method to study the relationship between short-peptide antigenic diversity and protein sequence diversity of dengue virus. We also studied the effects of sequence determinants on viral antigenic diversity. Short peptides, principally 9-mers were studied because they represent the predominant length of binding cores of T-cell epitopes, which are important for formulation of vaccines. RESULTS: Our analysis showed that the number of unique protein sequences required to represent complete antigenic diversity of short peptides in dengue virus is significantly smaller than that required to represent complete protein sequence diversity. Short-peptide antigenic diversity shows an asymptotic relationship to the number of unique protein sequences, indicating that for large sequence sets (~200) the addition of new protein sequences has marginal effect to increasing antigenic diversity. A near-linear relationship was observed between the extent of antigenic diversity and the length of protein sequences, suggesting that, for the practical purpose of vaccine development, antigenic diversity of short peptides from dengue virus can be represented by short regions of sequences (~<100 aa) within viral antigens that are specific targets of immune responses (such as T-cell epitopes specific to particular human leukocyte antigen alleles). CONCLUSION: This study provides evidence that there are limited numbers of antigenic combinations in protein sequence variants of a viral species and that short regions of the viral protein are sufficient to capture antigenic diversity of T-cell epitopes. The approach described herein has direct application to the analysis of other viruses, in particular those that show high diversity and/or rapid evolution, such as influenza A virus and human immunodeficiency virus (HIV)

Quantifying Inactive Lithium in Lithium Metal Batteries

Inactive lithium (Li) formation is the immediate cause of capacity loss and catastrophic failure of Li metal batteries. However, the chemical component and the atomic level structure of inactive Li have rarely been studied due to the lack of effective diagnosis tools to accurately differentiate and quantify Li+ in solid electrolyte interphase (SEI) components and the electrically isolated unreacted metallic Li0, which together comprise the inactive Li. Here, by introducing a new analytical method, Titration Gas Chromatography (TGC), we can accurately quantify the contribution from metallic Li0 to the total amount of inactive Li. We uncover that the Li0, rather than the electrochemically formed SEI, dominates the inactive Li and capacity loss. Using cryogenic electron microscopies to further study the microstructure and nanostructure of inactive Li, we find that the Li0 is surrounded by insulating SEI, losing the electronic conductive pathway to the bulk electrode. Coupling the measurements of the Li0 global content to observations of its local atomic structure, we reveal the formation mechanism of inactive Li in different types of electrolytes, and identify the true underlying cause of low Coulombic efficiency in Li metal deposition and stripping. We ultimately propose strategies to enable the highly efficient Li deposition and stripping to enable Li metal anode for next generation high energy batteries

Incorporation of albumin fusion proteins into fibrin clots in vitro and in vivo: comparison of different fusion motifs recognized by factor XIIIa

<p>Abstract</p> <p>Background</p> <p>The transglutaminase activated factor XIII (FXIIIa) acts to strengthen pathological fibrin clots and to slow their dissolution, in part by crosslinking active α₂-antiplasmin (α₂AP) to fibrin. We previously reported that a yeast-derived recombinant fusion protein comprising α₂AP residues 13-42 linked to human serum albumin (HSA) weakened <it>in vitro </it>clots but failed to become specifically incorporated into <it>in vivo </it>clots. In this study, our aims were to improve both the stability and clot localization of the HSA fusion protein by replacing α₂AP residues 13-42 with shorter sequences recognized more effectively by FXIIIa.</p> <p>Results</p> <p>Expression plasmids were prepared encoding recombinant HSA with the following N-terminal 23 residue extensions: H₆NQEQVSPLTLLAG₄Y (designated XL1); H₆DQMMLPWAVTLG₄Y (XL2); H₆WQHKIDLPYNGAG₄Y (XL3); and their 17 residue non-His-tagged equivalents (XL4, XL5, and XL6). The HSA moiety of XL4- to XL6-HSA proteins was C-terminally His-tagged. All chimerae were efficiently secreted from transformed <it>Pichia pastoris </it>yeast except XL3-HSA, and following nickel chelate affinity purification were found to be intact by amino acid sequencing, as was an N-terminally His-tagged version of α₂AP(13-42)-HSA. Of the proteins tested, XL5-HSA was cross-linked to biotin pentylamine (BPA) most rapidly by FXIIIa, and was the most effective competitor of α₂AP crosslinking not only to BPA but also to plasma fibrin clots. In the mouse ferric chloride <it>vena cava </it>thrombosis model, radiolabeled XL5-HSA was retained in the clot to a greater extent than recombinant HSA. In the rabbit jugular vein stasis thrombosis model, XL5-HSA was also retained in the clot, in a urea-insensitive manner indicative of crosslinking to fibrin, to a greater extent than recombinant HSA.</p> <p>Conclusions</p> <p>Fusion protein XL5-HSA (DQMMLPWAVTLG₄Y-HSAH₆) was found to be more active as a substrate for FXIIIa-mediated transamidation than seven other candidate fusion proteins <it>in vitro</it>. The improved stability and reactivity of this chimeric protein was further evidenced by its incorporation into <it>in vivo </it>clots formed in thrombosis models in both mice and rabbits.</p

Epidemiology and Trends of Infective Meningitis in Neonates and Infants Less than 3 Months Old in Hong Kong

Objectives: Meningitis in neonates and young infants leads to significant morbidity and mortality worldwide. This study aimed to investigate pathogens, antibiotic resistance and secular change of incidence in Hong Kong. Methods: A retrospective search was performed on meningitis in neonates and infants aged <3 months in three Hong Kong public hospitals from 2004 to 2019. Medical charts were reviewed, with focus on the identification and antibiotic resistance of the pathogens. Results: A total of 200 cases of meningitis were identified (67% were bacterial). Group B Streptococcus (GBS) and Escherichia coli (E. coli) were the commonest bacterial pathogens. The annual rates of early-onset GBS meningitis decreased after the implementation of universal GBS screening and intrapartum antibiotic prophylaxis (IAP) in 2012, while that of late-onset GBS meningitis remained similar. A significant portion of E. coli isolates were resistant to ampicillin and/or gentamicin. Conclusion: GBS and E. coli were the most common bacteria for meningitis in this age group. The annual rate of bacterial meningitis in Hong Kong has declined in recent years, which has been attributed to the decline in early-onset GBS meningitis due to universal GBS screening and IAP. Antimicrobial-resistant bacterial strains that cause meningitis require further clinical and public health attention