Bacterial Cell Envelope Lysis and Hemotoxicity of Peptides Previously isolated From African Catfish, Clarias gariepinus

Background: The skin mucus layer of fish is endowed with biologics including, Antimicrobial peptides (AMPs) that offer a first line of defence against pathogens. Such peptides can either inhibit bacterial growth or completely kill the bacteria and hence are regarded as a viable alternative to traditional antibiotics, in addressing the ever-increasing incidences of antimicrobial resistance. However, one of the major hurdles to AMPs use is their poor haemolytic profile. As a result, a thorough evaluation of prospective AMPs’ bacterial cell membrane disruption and hemolytic potentials in the early phases of drug discovery is critical. The current study presented cell membrane destruction as well as hemo-compatibility of antimicrobial peptides previously isolated from skin mucus of African catfish, Clarias gariepinus.Methods: A previously isolated antimicrobial peptide in the skin mucus of African catfish, C. gariepinus were profiled using 15% Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). The electrical conductivity and alkaline phosphatase assays were utilised to measure bacterial cell envelope lysis activity as a classical mode of action of the antimicrobial peptides. Afterwards, fresh Rabbit blood cells were then utilised for in vitro hemolytic assay.Results: The peptides were found to be about 5 kDa molecular weight with, ability to damage the bacterial cell envelope causing significant leakage in periplasmic alkaline phosphatase enzyme and cytoplasmic electrolytes. Even at the highest peptide extract concentration of 100 μg/mL, no significant hemolysis was observed on the fresh rabbit blood cells [3.63%;P>.05], signifying their safety on normal mammalian cells.Conclusion: The findings of this study pointed out that antimicrobial peptides in skin mucus of C. gariepinus are potentially safe source of antimicrobial drug leads; however, further studies are still required to search for possibly maximum dose that is safe to host cells but still effective against infecting bacteria

Comparison of rose bengal plate test, serum agglutination test, and indirect enzyme-linked immunosorbent assay in brucellosis detection for human and goat samples

Background: In Uganda, detection of brucellosis in goats and humans is more frequently done using rose bengal plate test (RBPT) in comparison to other serological tests such as serum agglutination test (SAT) and indirect enzyme-linked immunosorbent assay (i-ELISA). Aim: This study aimed at estimating the degree of agreement, specificity and sensitivity of RBPT, SAT, and ELISA in brucellosis detection in human and goat samples. Materials and Methods: An analytical study was conducted involving parallel testing of 425 goat samples and 177 human samples to compare RBPT, SAT, and i-ELISA tests of brucellosis detection. Results: A seroprevalence of 14.82% in animals and 11.86% in humans was detected using RBPT, 7.06% in goats and 5.09% in humans using SAT, and 6.35% in humans and 4.52% in animals using i-ELISA. The degree of agreement between the three tests in humans and animals was compared using Fleiss' kappa statistics where a moderate agreement (MA) was obtained for both with kappa value 0.57 in animals and 0.51 in humans and p<0.001. Kappa values in animals were 0.52 (MA) for RBPT and i-ELISA, 0.61 (MA) for RBPT and SAT, and 0.82 substantial agreement (SA) for SAT and i-ELISA. The kappa values in humans were 0.52 (MA) for RBPT and i-ELISA, 0.57 (MA) for RBPT and SAT, and 0.82 (SA) for SAT and i-ELISA, respectively. The study revealed a significant agreement in the tests for all the three tests, but there was SA between SAT and i-ELISA in both animal and human samples. Sensitivity and specificity of RBT and SAT were estimated using i-ELISA as a gold standard as follows, in goats RBPT: 100 and 91% and SAT: 100 and 99%, respectively, and in humans RBPT: 100 and 92% and SAT: 88 and 99%, respectively. Conclusion: It appears that RBPT is good as a screening test, whereas SAT and i-ELISA are good for diagnosis purposes or confirmatory test

Analysis of the MUII-plus mentorship programme: reflections of Fellows’ experiences and lessons for other programmes

Background: The MUII mentorship programme began 11 years ago with a successful group mentorship model. Over the years, the programme has evolved and is presently anchored on the “GROW” approach. This model allows individuals to: set Goals (What I want?); Reflect (Where am I now?); think of Options (What can I do?); What to implement (my actions?). It is intended to help fellows (current, honorary, alumni) herein referred to as mentees achieve their short, medium, and long-term research, career and professional goals. Methods: A mixed methods study combining a cross-sectional survey, one focus group discussion and 11 in-depth key informant interviews were carried out between November 2018 and January 2019 to 1) assess the status of the mentorship programme, 2) perform a strength weakness opportunity and threats (SWOT) analysis, and 3) identify factors relevant for sustainability. Results: An open invitation was made to 52 fellows to participate in the survey, and 23 responded. Among respondents, the largest proportions were male [70% (16/23)], and PhD fellows [35% (8/23)]. The respondents rated the fellowship experience as excellent [65% (15/23)], and most [78% (18/23)] revealed they had benefitted greatly from the programme. The SWOT analysis revealed outstanding strengths of having regular fellows’ meetings for peer support, and availability of international collaborations, linkages and exposure. Opportunities identified included large pool of mentees within MUII-plus and evidence of fellows taking up leadership positions. The biggest threat to the mentorship programme was the busy schedule of mentors. Conclusions: The MUII-plus mentorship programme has strong potential to offer research and career mentorship to its fellows. To promote sustainability of the programme, there is a need for innovative ways to engage mentors; such as digital platforms (e-mentorship) for greater mentor-mentee interactions.</ns3:p

Analysis of the MUII-plus mentorship programme: reflections of Fellows� experiences and lessons for other programmes

Background: The MUII mentorship programme began 11 years ago with a successful group mentorship model. Over the years, the programme has evolved and is presently anchored on the �GROW� approach. This model allows individuals to: set Goals (What I want?); Reflect (Where am I now?); think of Options (What can I do?); What to implement (my actions?). It is intended to help fellows (current, honorary, alumni) herein referred to as mentees achieve their short, medium, and long-term research, career and professional goals. Methods: A mixed methods study combining a cross-sectional survey, one focus group discussion and 11 in-depth key informant interviews were carried out between November 2018 and January 2019 to 1) assess the status of the mentorship programme, 2) perform a strength weakness opportunity and threats (SWOT) analysis, and 3) identify factors relevant for sustainability. Results: An open invitation was made to 52 fellows to participate in the survey, and 23 responded. Among respondents, the largest proportions were male [70% (16/23)], and PhD fellows [35% (8/23)]. The respondents rated the fellowship experience as excellent [65% (15/23)], and most [78% (18/23)] revealed they had benefitted greatly from the programme. The SWOT analysis revealed outstanding strengths of having regular fellows� meetings for peer support, and availability of international collaborations, linkages and exposure. Opportunities identified included large pool of mentees within MUII-plus and evidence of fellows taking up leadership positions. The biggest threat to the mentorship programme was the busy schedule of mentors. Conclusions: The MUII-plus mentorship programme has strong potential to offer research and career mentorship to its fellows. To promote sustainability of the programme, there is a need for innovative ways to engage mentors; such as digital platforms (e-mentorship) for greater mentor-mentee interactions.</ns3:p

Transcriptome analysis of peripheral blood of Schistosoma mansoni infected children from the Albert Nile region in Uganda reveals genes implicated in fibrosis pathology.

Over 290 million people are infected by schistosomes worldwide. Schistosomiasis control efforts focus on mass drug treatment with praziquantel (PZQ), a drug that kills the adult worm of all Schistosoma species. Nonetheless, re-infections have continued to be detected in endemic areas with individuals living in the same area presenting with varying infection intensities. Our objective was to characterize the transcriptome profiles in peripheral blood of children between 10-15 years with varying intensities of Schistosoma mansoni infection living along the Albert Nile in Uganda. RNA extracted from peripheral blood collected from 44 S. mansoni infected (34 high and 10 low by circulating anodic antigen [CAA] level) and 20 uninfected children was sequenced using Illumina NovaSeq S4 and the reads aligned to the GRCh38 human genome. Differential gene expression analysis was done using DESeq2. Principal component analysis revealed clustering of gene expression by gender when S. mansoni infected children were compared with uninfected children. In addition, we identified 14 DEGs between S. mansoni infected and uninfected individuals, 56 DEGs between children with high infection intensity and uninfected individuals, 33 DEGs between those with high infection intensity and low infection intensity and no DEGs between those with low infection and uninfected individuals. We also observed upregulation and downregulation of some DEGs that are associated with fibrosis and its regulation. These data suggest expression of fibrosis associated genes as well as genes that regulate fibrosis in S. mansoni infection. The relatively few significant DEGS observed in children with schistosomiasis suggests that chronic S. mansoni infection is a stealth infection that does not stimulate a strong immune response

Recommendations for design and conduct of preclinical in vivo studies of orthopedic device-related infection

Orthopedic device-related infection (ODRI), including both fracture-related infection (FRI) and periprosthetic joint infection (PJI), remain amongst the most challenging complications in orthopedic and musculoskeletal trauma surgery. ODRI has been convincingly shown to delay healing, worsen functional outcome and incur significant socio-economic costs. To address this clinical problem, ever more sophisticated technologies targeting the prevention and/or treatment of ODRI are being developed and tested in vitro and in vivo. Amongst the most commonly described innovations are antimicrobial-coated orthopedic devices, antimicrobial-loaded bone cements and void fillers, and dual osteo-inductive/antimicrobial biomaterials. Unfortunately, translation of these technologies to the clinic has been limited, at least partially due to the challenging and still evolving regulatory environment for antimicrobial drug-device combination products, and a lack of clarity in the burden of proof required in preclinical studies. Preclinical in vivo testing (i.e. animal studies) represents a critical phase of the multidisciplinary effort to design, produce and reliably test both safety and efficacy of any new antimicrobial device. Nonetheless, current in vivo testing protocols, procedures, models and assessments are highly disparate, irregularly conducted and reported, and without standardization and validation. The purpose of the present opinion piece is to discuss best practices in preclinical in vivo testing of antimicrobial interventions targeting ODRI. By sharing these experience-driven views, we aim to aid others in conducting such studies both for fundamental biomedical research, but also for regulatory and clinical evaluation

ADMET profiling and molecular docking of potential antimicrobial peptides previously isolated from African catfish, Clarias gariepinus

Amidst rising cases of antimicrobial resistance, antimicrobial peptides (AMPs) are regarded as a promising alternative to traditional antibiotics. Even so, poor pharmacokinetic profiles of certain AMPs impede their utility necessitating, a careful assessment of potential AMPs’ absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties during novel lead exploration. Accordingly, the present study utilized ADMET scores to profile seven previously isolated African catfish antimicrobial peptides (ACAPs). After profiling, the peptides were docked against approved bacterial protein targets to gain insight into their possible mode of action. Promising ACAPs were then chemically synthesized, and their antibacterial activity was validated in vitro utilizing the broth dilution method. All seven examined antimicrobial peptides passed the ADMET screening, with two (ACAP-IV and ACAP-V) exhibiting the best ADMET profile scores. The ACAP-V had a higher average binding energy (−8.47 kcal/mol) and average global energy (−70.78 kcal/mol) compared to ACAP-IV (−7.60 kcal/mol and −57.53 kcal/mol), with the potential to penetrate and disrupt bacterial cell membrane (PDB Id: 2w6d). Conversely, ACAP-IV peptide had higher antibacterial activity against E. coli and S. aureus (Minimum Inhibitory Concentration, 520.7 ± 104.3 μg/ml and 1666.7 ± 416.7 μg/ml, respectively) compared to ACAP-V. Collectively, the two antimicrobial peptides (ACAP-IV and ACAP-V) are potential novel leads for the food, cosmetic and pharmaceutical industries. Future research is recommended to optimize the expression of such peptides in biological systems for extended evaluation

An International Multicenter Cohort Study on beta-Blockers for the Treatment of Symptomatic Children With Catecholaminergic Polymorphic Ventricular Tachycardia

Background: Symptomatic children with catecholaminergic polymorphic ventricular tachycardia (CPVT) are at risk for recurrent arrhythmic events. β-Blockers decrease this risk, but studies comparing individual β-blockers in sizeable cohorts are lacking. We aimed to assess the association between risk for arrhythmic events and type of β-blocker in a large cohort of symptomatic children with CPVT.Methods: From 2 international registries of patients with CPVT, RYR2 variant–carrying symptomatic children (defined as syncope or sudden cardiac arrest before β-blocker initiation and age at start of β-blocker therapy &lt;18 years), treated with a β-blocker were included. Cox regression analyses with time-dependent covariates for β-blockers and potential confounders were used to assess the hazard ratio (HR). The primary outcome was the first occurrence of sudden cardiac death, sudden cardiac arrest, appropriate implantable cardioverter-defibrillator shock, or syncope. The secondary outcome was the first occurrence of any of the primary outcomes except syncope.Results: We included 329 patients (median age at diagnosis, 12 [interquartile range, 7–15] years, 35% females). Ninety-nine (30.1%) patients experienced the primary outcome and 74 (22.5%) experienced the secondary outcome during a median follow-up of 6.7 (interquartile range, 2.8–12.5) years. Two-hundred sixteen patients (66.0%) used a nonselective β-blocker (predominantly nadolol [n=140] or propranolol [n=70]) and 111 (33.7%) used a β1-selective β-blocker (predominantly atenolol [n=51], metoprolol [n=33], or bisoprolol [n=19]) as initial β-blocker. Baseline characteristics did not differ. The HRs for both the primary and secondary outcomes were higher for β1-selective compared with nonselective β-blockers (HR, 2.04 [95% CI, 1.31–3.17]; and HR, 1.99 [95% CI, 1.20–3.30], respectively). When assessed separately, the HR for the primary outcome was higher for atenolol (HR, 2.68 [95% CI, 1.44–4.99]), bisoprolol (HR, 3.24 [95% CI, 1.47–7.18]), and metoprolol (HR, 2.18 [95% CI, 1.08–4.40]) compared with nadolol, but did not differ from propranolol. The HR of the secondary outcome was only higher in atenolol compared with nadolol (HR, 2.68 [95% CI, 1.30–5.55]).Conclusions: β1-selective β-blockers were associated with a significantly higher risk for arrhythmic events in symptomatic children with CPVT compared with nonselective β-blockers, specifically nadolol. Nadolol, or propranolol if nadolol is unavailable, should be the preferred β-blocker for treating symptomatic children with CPVT.</p

Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass $M>70$ $M_\odot$) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities $0 < e \leq 0.3$ at $0.33$ Gpc$^{-3}$ yr$^{-1}$ at 90\% confidence level.Comment: 24 pages, 5 figure