Graphene-Based Bacterial Filtration via Electrostatic Adsorption

Flexible graphene oxide (GO) microsheets with attached positively charged polymers, termed GOX microsheets, are efficient at bacterial adsorption, as they bind electrostatically to bacterial membranes’ negative surface charge. The authors explore an antimicrobial water filter application for GOX's extremely high surface area and its previously described efficient bacterial adsorption.Cellulose-fiber carrier material is functionalized with GOX microsheets to create an adsorption-based bacteria filtration material. The morphology and charge density (7.8 × 1019 g–1) of the prepared GOX fibers are determined by scanning electron microscopy and dye adsorption assay, and widefield fluorescence microscopy is used to visualize the adsorption of stained Escherichia coli bacterial cells on the fibers. GOX fibers are tested in filtration setups to investigate their bacteria removal performance. The experimental results, with 100 mg of GOX fibers filtering 2.4 × 109 colony-forming units (CFU) from an E. coli bacterial culture with 99.5% bacterial reduction, demonstrate the fibers’ high bacteria loading capacity. The electrostatic adsorption-based filtration mechanism allows the filter to be operated at higher flow rates than micropore membrane filters, while maintaining 3-log bacterial reduction. GOX filter materials removing bacteria via adsorption are a high flow rate alternative to current water filtration processes that rely on size-exclusion

Multivalent bacteria binding by flexible polycationic microsheets matching their surface charge density

Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer‐modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction. Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram‐negative and ‐positive bacteria (E. coli and methicillin‐resistant Staphylococcus aureus , MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time. This new type of antibacterial agent acts in a different mode of action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies

Seroprevalence of SARS‑CoV‑2 in German secondary schools from October 2020 to July 2021: a longitudinal study

Purpose: To quantify the number of SARS-CoV-2 infections in students and teachers in 14 Secondary schools in eastern Saxony, Germany. Seroprevalence of SARS-CoV-2 antibodies in study population. Number of undetected cases. - Methods: Serial seroprevalence study. - Results: The role of educational settings in the SARS-CoV-2 Pandemic is still controversial. Seroprevalence increases from 0.8 to 5.9% from October to December when schools remained open and to 12.2% in March/April during a strict lockdown with closed schools. The ratio of undetected to detected cases decreased from 0.76 to 0.44 during the study period. - Conclusion: During the second and third wave of the pandemic in Germany, students and teachers are not overrepresented in SARS-CoV-2 infections. The percentage of undetected cases is moderate and decreases over time. The risk of contracting SARS-CoV-2 within the household is higher than contracting it in educational settings making school closures rather ineffective in terms of pandemic control measures or individual risk reduction in children and adolescents. - Trial registration: DRKS00022455 (July 23rd, 2020)

Platelet transfusion versus standard care after acute stroke due to spontaneous cerebral haemorrhage associated with antiplatelet therapy (PATCH): a randomised, open-label, phase 3 trial

Item does not contain fulltextBACKGROUND: Platelet transfusion after acute spontaneous primary intracerebral haemorrhage in people taking antiplatelet therapy might reduce death or dependence by reducing the extent of the haemorrhage. We aimed to investigate whether platelet transfusion with standard care, compared with standard care alone, reduced death or dependence after intracerebral haemorrhage associated with antiplatelet therapy use. METHODS: We did this multicentre, open-label, masked-endpoint, randomised trial at 60 hospitals in the Netherlands, UK, and France. We enrolled adults within 6 h of supratentorial intracerebral haemorrhage symptom onset if they had used antiplatelet therapy for at least 7 days beforehand and had a Glasgow Coma Scale score of at least 8. With use of a secure web-based system that concealed allocation and used biased coin randomisation, study collaborators randomly assigned participants (1:1; stratified by hospital and type of antiplatelet therapy) to receive either standard care or standard care with platelet transfusion within 90 min of diagnostic brain imaging. Participants and local investigators giving interventions were not masked to treatment allocation, but allocation was concealed from outcome assessors and investigators analysing data. The primary outcome was shift towards death or dependence rated on the modified Rankin Scale (mRS) at 3 months, and analysed by ordinal logistic regression, adjusted for stratification variables and the Intracerebral Haemorrhage Score. The primary analysis was done in the intention-to-treat population and safety analyses were done in the intention-to-treat and as-treated populations. This trial is registered with the Netherlands Trial Register, number NTR1303, and is now closed. FINDINGS: Between Feb 4, 2009, and Oct 8, 2015, 41 sites enrolled 190 participants. 97 participants were randomly assigned to platelet transfusion and 93 to standard care. The odds of death or dependence at 3 months were higher in the platelet transfusion group than in the standard care group (adjusted common odds ratio 2.05, 95% CI 1.18-3.56; p=0.0114). 40 (42%) participants who received platelet transfusion had a serious adverse event during their hospital stay, as did 28 (29%) who received standard care. 23 (24%) participants assigned to platelet transfusion and 16 (17%) assigned to standard care died during hospital stay. INTERPRETATION: Platelet transfusion seems inferior to standard care for people taking antiplatelet therapy before intracerebral haemorrhage. Platelet transfusion cannot be recommended for this indication in clinical practice. FUNDING: The Netherlands Organisation for Health Research and Development, Sanquin Blood Supply, Chest Heart and Stroke Scotland, French Ministry of Health

Who is best to test? A systematic review of chlamydia infections in Switzerland

In many countries, community pharmacies provide sexual-health-related services to limit the spread of sexually transmitted infections (STIs), including chlamydia testing. To identify suitable target groups for pharmacy-based chlamydia testing in Switzerland, we aimed to assess chlamydia prevalence, identify risk groups, and delineate screening strategies. We conducted a systematic literature search up to December 2019 in PubMed, EMBASE, and Web of Science, according to the PRISMA guidelines, using as keywords "chlamydia", "screening", and "Switzerland". Two researchers screened the title, abstract, and full-text article and assessed the methodological quality. The literature search generated 108 hits, and nine studies were included. Chlamydia prevalence ranged between 0.8 and 12.8%. Most frequently affected were undocumented women undergoing voluntary termination of pregnancy (12.8%, 95% CI: 8.4-18.9), HIV-positive men who have sex with men (10.9%, 95% CI: 9.2-17.6), and adult offenders (6.5%, 95% CI: 3.2-9.0). Systematic screening was suggested for the first two risk groups and women suffering a miscarriage. To conclude, chlamydia infections are prevalent in Switzerland, but the identified risk groups are difficult to reach for a pharmacy-based testing service. More studies are needed to identify suitable target groups, including customers seeking sexual health services, particularly emergency contraception users who already receive counselling for STIs at community pharmacies

Functional and structural analysis of photosystem II core complexes from spinach with high oxygen evolution capacity

Oxygen-evolving photo system II core complexes were prepared from spinach by solubilizing photosystem II membrane fragments with dodecyl-β-D-maltoside. The core complexes consist of the intrinsic 47-kDa, 43-kDa, D1 and D2 polypeptides, the two subunits of cytochrome b559 and the extrinsic 33-kDa protein. In the presence of 50 mM CaCl2 they exhibit a high oxygen evolution rate of 1.3 ± 0.2 mmol O2 • mg chlorophyll–1 • h–1 with either 2,6-dichloro-benzoquinone or K3[Fe(CN)6] as acceptor. Electron micrographs of these complexes reveal an obtuse triangular structure in when viewed from the top, measuring 15.3 nm on one side and 10.6 nm on the other two sides. An average height of 7.3 nm was determined from the side view position. These data are in good agreement with previously reported dimensions for photosystem II core complexes. In contrast to previous reports the extrinsic 33-kDa subunit could be resolved for the first time. It appears as a small protrusion when the complex is viewed from the side and seems to cover the lumenal side of the core complex appearing as a disk with a thickness of 1.5–3.3 nm.

SARS-CoV-2 transmissions in students and teachers: seroprevalence follow-up study in a German secondary school in November and December 2020

Objective To quantify the number of undetected SARS-CoV-2 infections in educational settings.Design Serial SARS-CoV-2 seroprevalence study before and during the second wave of the COVID-19 pandemic.Setting Secondary school in Dresden, Germany.Participants Grade 8–12 students and their teachers were invited to participate in serial blood sampling and SARS-CoV-2 IgG antibody assessment.Main outcome measure Seroprevalence of SARS-CoV-2 antibodies in study population.Results 247 students and 55 teachers participated in the initial study visit and 197 students and 40 teachers completed follow-up. Seroprevalence increased from 1.7% (0.3–3.3) to 6.8% (3.8–10.1) during the study period mirroring the increase of officially reported SARS-CoV-2 infections during this time. The ratio of undetected to detected SARS-CoV-2 infections ranged from 0.25 to 0.33.Conclusions We could not find evidence of relevant silent, asymptomatic spread of SARS-CoV-2 in schools neither in a low prevalence setting nor during the second wave of the pandemic, making it unlikely that educational settings play a crucial role in driving the SARS-CoV-2 pandemic.Trial registration number DRKS00022455

Transcriptomic analysis of stress response to novel antimicrobial coatings in a clinical MRSA strain

Multi-drug resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) cause nosocomial infections that can have deleterious effects on human health. Thus, it is imperative to find solutions to treat these detrimental infections as well as to control their spread. We tested the effect of two different antimicrobial materials, functionalised graphene oxide (GOX), and AGXX® coated on cellulose fibres, on the growth and transcriptome of the clinical MRSA strain S. aureus 04-02981. In addition, we investigated the effect of a third material as a combination of GOX and AGXX® fibres on S. aureus 04-02981. Standard plate count assay revealed that the combination of fibres, GOX-AGXX® inhibited the growth of S. aureus 04-02981 by 99.98%. To assess the effect of these antimicrobials on the transcriptome of our strain, cultures of S. aureus 04-02981 were incubated with GOX, AGXX®, or GOX-AGXX® fibres for different time periods and then subjected to RNA-sequencing. Uncoated cellulose fibres were used as a negative control. The antimicrobial fibres had a huge impact on the transcriptome of S. aureus 04-02981 affecting the expression of 2650 genes. Primarily genes related to biofilm formation and virulence (such as agr, sarA, and those of the two-component system SaeRS), and genes crucial for survival in biofilms (like arginine metabolism arc genes) were repressed. In contrast, the expression of siderophore biosynthesis genes (sbn) was induced, a probable response to stress imposed by the antimicrobials and the conditions of iron-deficiency. Genes associated with potassium transport, intracellular survival and pathogenesis (kdp) were also differentially expressed. Our data suggest that the combination of GOX and AGXX® acts as an efficient antimicrobial against S. aureus 04-02981. Thus, these materials are potential candidates for applications in antimicrobial surface coatings

Table_2_The “chicken-leg anastomosis”: Low-cost tissue-realistic simulation model for esophageal atresia training in pediatric surgery.docx

IntroductionShifting the training from the operating room (OR) to simulation models has been proven effective in enhancing patient safety and reducing the learning time to achieve competency and increase the operative efficiency. Currently the field of pediatric surgery only offers few low-cost trainers for specialized training and these feature predominantly artificial and often unrealistic tissue. The aim of this study was to develop an easy access low-cost tissue-realistic simulation model for open training of esophageal atresia and to evaluate the acceptance in trainees and junior pediatric surgeons.Materials and methodsThe model is fashioned using reconfigured chicken skin from a chicken leg. To create a model of esophageal atresia, the chicken skin is dissected off the muscle and reconfigured around a foley catheter balloon to recreate the proximal pouch and a feeding tube to recreate the distal pouch. Surrounding structures such as the tracheo-esophageal fistula and the azygos vein can be easily added, obtaining a realistic esophageal atresia (Type C) prototype. Evaluation of model construction, usage and impact on user were performed by both a self-assessment questionnaire with pre- and post-training questions as well as observer-based variables and a revised Objective Structured Assessment of Technical Skills (OSATS) score.ResultsA total of 10 participants were constructing and using the model at two different timepoints. OSATS score for overall performance was significantly higher (p = 0.005, z = −2.78) during the second observational period [median (MD): 4,95% confidence interval CI: 3.4, 5.1] compared to the first (MD: 3, 95% CI 2.4, 4.1). Self-reported boost in confidence after model usage for performing future esophageal atresia (EA) repair and bowel anastomosis (BA) in general was significantly higher (EA: U = 1, z = −2.3, p = 0.021, BA: U = 1, z = −2.41, p = 0.016) in participants with more years in training/attending status (EA MD:5, BA MD: 5.5) compared to less experienced participants (EA MD: 1.5, BA: 1).ConclusionOur easy access low-cost simulation model represents a feasible and tissue realistic training option to increase surgical performance of pediatric surgical trainees outside the OR.</p

Insights for public education provided by French media on ideas about prostate cancer – A media analysis study

Background: This study explored the French media’s presentation of ideas and medical information about prostate cancer (PC) that may influence men’s understanding, attitudes and behavior. Methods: A qualitative media content analysis centered on PC information delivered by French professional media. The selected data were produced in the aftermath of the High Health Authority's decision in 2008 not to recommend systematic screening by prostate specific antigen(PSA) for men over 50. Source was the Media Archives of the French National Library. Content was analyzed from 15 television programs, 14 radio programs, and 55 articles from 35 popular French newspapers (online and printed, weekly and monthly) and 20 magazines. Audio content was narrated into textual form and submitted to manual coding along with the print content.Results: Television and radio content focused on the nature of PC, screening and treatment,and conveyed a gender-centric position linked to male sexuality and virility. Newspapers and magazines targeted the testing controversy, the lack of consensus among professionals, and scientific advances in screening and treatment.Conclusion: Media participation in the European testing debate is valuable for allowing patients to hear all opinions on PC risk factors. Debate on testing policy contributes to confusion and uncertainty regarding appropriate action