F508del disturbs the dynamics of the nucleotide binding domains of CFTR before and after ATP hydrolysis.

The cystic fibrosis transmembrane conductance regulator (CFTR) channel is an ion channel responsible for chloride transport in epithelia and it belongs to the class of ABC transporters. The deletion of phenylalanine 508 (F508del) in CFTR is the most common mutation responsible for cystic fibrosis. Little is known about the effect of the mutation in the isolated nucleotide binding domains (NBDs), on dimer dynamics, ATP hydrolysis and even on nucleotide binding. Using molecular dynamics simulations of the human CFTR NBD dimer, we showed that F508del increases, in the prehydrolysis state, the inter-motif distance in both ATP binding sites (ABP) when ATP is bound. Additionally, a decrease in the number of catalytically competent conformations was observed in the presence of F508del. We used the subtraction technique to study the first 300 ps after ATP hydrolysis in the catalytic competent site and found that the F508del dimer evidences lower conformational changes than the wild type. Using longer simulation times, the magnitude of the conformational changes in both forms increases. Nonetheless, the F508del dimer shows lower C-α RMS values in comparison to the wild-type, on the F508del loop, on the residues surrounding the catalytic site and the portion of NBD2 adjacent to ABP1. These results provide evidence that F508del interferes with the NBD dynamics before and after ATP hydrolysis. These findings shed a new light on the effect of F508del on NBD dynamics and reveal a novel mechanism for the influence of F508del on CFTR.

Unexplored Nucleotide Binding Modes for the ABC Exporter MsbA.

The ATP-binding cassette (ABC) transporter MsbA is an ATP-driven lipid-A flippase. It belongs to the ABC protein superfamily whose members are characterized by conserved motifs in their nucleotide binding domains (NBDs), which are responsible for ATP hydrolysis. Recently, it was found that MsbA could catalyze a reverse adenylate kinase (rAK)-like reaction in addition to ATP hydrolysis. Both reactions are connected and mediated by the same conserved NBD domains. Here, the structural foundations underlying the nucleotide binding to MsbA were therefore explored using a concerted approach based on conventional- and DNP-enhanced solid-state NMR, pulsed-EPR, and MD simulations. MsbA reconstituted into lipid bilayers was trapped in various catalytic states corresponding to intermediates of the coupled ATPase-rAK mechanism. The analysis of nucleotide-binding dependent chemical shift changes, and the detection of through-space contacts between bound nucleotides and MsbA within these states provides evidence for an additional nucleotide-binding site in close proximity to the Q-loop and the His-Switch. By replacing Mg2+ with Mn2+ and employing pulsed EPR spectroscopy, evidence is provided that this newly found nucleotide binding site does not interfere with the coordination of the required metal ion. Molecular dynamic (MD) simulations of nucleotide and metal binding required for the coupled ATPase-rAK mechanism have been used to corroborate these experimental findings and provide additional insight into nucleotide location, orientation, and possible binding modes.

Dispersing Carbon Nanotubes with Ionic Surfactants under Controlled Conditions: Comparisons and Insight.

A fundamental understanding of the mechanisms involved in the surfactant-assisted exfoliation and dispersion of carbon nanotubes (CNTs) in water calls for well-controlled experimental methodologies and reliable comparative metrics. We have assessed the ability of several ionic surfactants to disperse single and multiwalled carbon nanotubes, resorting to a stringently controlled sonication-centrifugation method for the preparation of the dispersions. The CNT concentration was accurately measured for a wide range of surfactant concentration, using combined thermogravimetric analysis and UV-vis spectroscopy. The obtained dispersibility curves yield several quantitative parameters, which in turn allow for the effects of nanotube morphology and surfactant properties (aromatic rings, chain length, headgroup charge, and cmc) to be assessed and rationalized, both in terms of dispersed nanotube mass and surface area. The data also indicate that the CNT-surfactant association follows patterns that are markedly different from other equilibrium processes governed by hydrophobicity (such as micellization); in particular, the surfactant concentration needed for maximum dispersibility, c(s,max), and the number of surfactant molecules per unit CNT area at c(s,max) are shown to depend linearly on chain length. The results further suggest that the presence of micelles in the exfoliation process is not a key factor either for starting CNT dispersibility or attaining its saturation value.

Ternary (molybdenum disulfide/graphene)/carbon nanotube nanocomposites assembled via a facile colloidal electrostatic path as electrocatalysts for the oxygen reduction reaction: Composition and nitrogen-doping play a key role in their performance.

Nanocomposites have garnered attention for their potential as catalysts in electrochemical reactions vital for technologies like fuel cells, water splitting, and metal-air batteries. This work focuses on developing three-dimensional (3D) nanocomposites through aqueous phase exfoliation, non-covalent functionalization of building blocks with surfactants and polymers, and electrostatic interactions in solution leading to the nanocomposites assembly and organization. By combining molybdenum disulfide (MoS2) layers with graphene nanoplatelets (GnPs) to form a binary 2D composite (MoS2/GnP), and subsequently incorporating multiwalled carbon nanotubes (MWNTs) to create ternary 3D composites, we explore their potential as catalysts for the oxygen reduction reaction (ORR) critical in fuel cells. Characterization techniques such as X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction elucidate material composition and structure. Our electrochemical studies reveal insights into the kinetics of the reactions and structure-activity relationships. Both the (MoS2/GnP)-to-MWNT mass ratio and nitrogen-doping of GnPs (N-GnPs) play a key role on the electrocatalytic ORR performance. Notably, the (MoS2/N-GnP)/MWNT material, with a 3:1 mass ratio, exhibits the most effective ORR activity. All catalysts demonstrate good long-term stability and methanol crossover tolerance. This facile fabrication method and observed trends offer avenues for optimizing composite electrocatalysts further.

Fertility preservation in female cancer patients in Brazil: perceptions and attitudes of infertility specialists.

Objective: Fertility preservation is a priority in oncology for female cancer patients. However, there is a lack of communication between infertility specialists and oncologists. This study aimed to evaluate infertility specialists' perceptions and experiences regarding fertility preservation. Methods: Conduct an online survey to profile infertility specialists. Participants were infertility affiliated with the Brazilian Federation of Gynecology and Obstetrics Associations (FEBRASGO). The specialists received an online survey, which response rate were 30.9%, most of whom were in southern and southeastern. The survey consisted on 14 questions about the infertility specialists' location, techniques in clinical practice, treatment successful rate, patients idea, etc. Results: The average experience in human reproduction were 15.5 ± 10.2 years (mean ± standard deviation, range 1-40). Among reproductive-aged female cancer patients recommended for fertility preservation, 60.3 ± 28.8% (range 10-100%) underwent preservation procedures. Main barriers were cost (41%), oncologists' knowledge or acceptance (35%) and accessibility (9%). Most infertility specialists (58%) considered 40 years the limit for fertility preservation. Leukemia, lymphoma, breast and ovarian cancers were prioritized for fertility preservation, while lung, thyroid, gastric, and brain cancers were less relevant. Conclusion: This is the first Brazilian study about infertility specialists' perceptions on oncology patients access to fertility preservation. These patients primarily receive treatment in the public health system, while infertility specialists mainly work in the private healthcare. This healthcare mode is currently fragmented, but integrating these experts is enhancing patient access to fertility preservation. Studies on this topic are still warranted.

A critical assessment of the role of ionic surfactants in the exfoliation and stabilization of 2D nanosheets: The case of the transition metal dichalcogenides MoS2, WS2 and MoSe2.

Transition metal dichalcogenides (TMDs), like other two-dimensional layered materials beyond graphene, have gained enormous interest in recent years owing to their distinct electronic and optical properties, and potential applicability in areas such as sensing, nanoelectronics and catalysis. Surfactant-assisted exfoliation is commonly used to prepare aqueous dispersions of TMD nanosheets, but a clear picture of the TMD and surfactant features that influence the dispersion process is still lacking. In this work, we present a systematic study of the dispersibility of MoS2, WS2 and MoSe2 in aqueous medium using a cationic (cetyltrimethylammonium bromide, CTAB) and an anionic (sodium cholate, SC) dispersant, in a wide concentration range (seven orders of magnitude) and resorting to a carefully controlled sonication-centrifugation procedure. We present detailed, high precision dispersibility curves (concentration of dispersed TMD versus concentration of surfactant used), together with zeta potential and pH measurements, allowing insight into the influence of the type of metal and chalcogen, surfactant charge and surfactant concentration, on the effectiveness of the exfoliation and stabilization. The metal (Mo vs. W) influences the dispersibility at low surfactant concentrations, while the chalcogen (S vs. Se) plays a more significant role as the surfactant concentration is increased, alongside the surfactant charge. Structural characterization by scanning electron microscopy (SEM), Raman spectroscopy and atomic force microscopy (AFM) shows that the methodology applied yields well-exfoliated nanosheets with controlled mean lateral dimension (≈ 100 nm) and thickness (≤5 layers). Finally, the type of ionic surfactant (cationic vs. anionic) and its concentration play a pivotal role in the profile of the dispersibility curves, leading us to propose two types of master curves with distinct regions of phase behavior.

Implementation and Short-term Adverse Events of Anti-SARS-CoV-2 Vaccines in Inflammatory Bowel Disease Patients: An International Web-based Survey.

INTRODUCTION: Anti-SARS-CoV-2 vaccine clinical trials did not include patients with immune-mediated conditions such as inflammatory bowel disease [IBD]. We aimed to describe the implementation of anti-SARS-CoV-2 vaccination among IBD patients, patients' concerns, and the side effect profile of the anti-SARS-CoV-2 vaccines, using real-world data. METHODS: An anonymous web-based self-completed survey was distributed in 36 European countries between June and July 2021. The results of the patient characteristics, concerns, vaccination status, and side effect profile were analysed. RESULTS: In all 3272 IBD patients completed the survey, 79.6% had received at least one dose of anti-SARS-CoV-2 vaccine, and 71.7% had completed the vaccination process. Patients over 60 years old had a significantly higher rate of vaccination [p < 0.001]. Patients' main concerns before vaccination were the possibility of having worse vaccine-related adverse events due to their IBD [24.6%], an IBD flare after vaccination [21.1%], and reduced vaccine efficacy due to IBD or associated immunosuppression [17.6%]. After the first dose of the vaccine, 72.4% had local symptoms and 51.4% had systemic symptoms [five patients had non-specified thrombosis]. Adverse events were less frequent after the second dose of the vaccine and in older patients. Only a minority of the patients were hospitalised [0.3%], needed a consultation [3.6%], or had to change IBD therapy [13.4%] after anti-SARS-CoV-2 vaccination. CONCLUSIONS: Although IBD patients raised concerns about the safety and efficacy of anti-SARS-CoV-2 vaccines, the implementation of vaccination in those responding to our survey was high and the adverse events were comparable to the general population, with minimal impact on their IBD.

Breaking Bad News in Obstetrics and Gynecology: We Must Talk About It.

Breaking bad news is common in obstetrics and gynecology (ob-gyn). However, it is difficult, and few doctors receive training on how to deal with this situation. This narrative review aims to gather, analyze, and synthesize part of the knowledge on the area, focused on Ob-Gyn. Among the 16 selected articles, two are randomized controlled intervention studies, and most studies refer to obstetrics. The results found by us pointed out that simulation, feedback/debriefing, lectures, and protocols could improve doctors' performance in communicating bad news. For patients, the context and how the information is transmitted seem to impact more than the content of the news. Ob-Gyn doctors could benefit from specific protocols and education, given the specialty's particularities. There is a lack of evidence about the most effective way to conduct such training. Finding validated ways to quantify and classify studies' results in the area, which would allow for the objective analysis of outcomes, is one of the biggest challenges concerning this topic.

Dar más notícias é comum em obstetrícia e ginecologia. Porém, é difícil e poucos médicos recebem treinamento sobre como lidar com essa situação. Esta revisão narrativa tem como objetivo reunir, analisar e sintetizar parte do conhecimento sobre a área, com foco na obstetrícia. Dentre os 16 artigos selecionados, dois são estudos de intervenção randomizados e controlados, e a maioria dos estudos refere-se à obstetrícia. Os resultados encontrados ressaltaram que simulação, feedback/entrevistas, palestras e protocolos podem melhorar o desempenho dos médicos na comunicação de más notícias. Para os pacientes, o contexto e como as informações são transmitidas parecem ter maior impacto do que o conteúdo das notícias. Os obstetras e ginecologistas poderiam se beneficiar de cursos e protocolos específicos, dadas as particularidades da especialidade. Faltam evidências sobre a forma mais eficaz de realizar esse treinamento. Encontrar formas validadas de quantificar e classificar os resultados dos estudos na área, permitindo uma análise objetiva dos resultados, é um dos maiores desafios neste tema.

ATP hydrolysis and nucleotide exit enhance maltose translocation in the MalFGK2E importer.

ATP binding cassette (ABC) transporters employ ATP hydrolysis to harness substrate translocation across membranes. The Escherichia coli MalFGK2E maltose importer is an example of a type I ABC importer and a model system for this class of ABC transporters. The MalFGK2E importer is responsible for the intake of malto-oligossacharides in E.coli. Despite being extensively studied, little is known about the effect of ATP hydrolysis and nucleotide exit on substrate transport. In this work, we studied this phenomenon using extensive molecular dynamics simulations (MD) along with potential of mean force calculations of maltose transport across the pore, in the pre-hydrolysis, post-hydrolysis and nucleotide-free states. We concluded that ATP hydrolysis and nucleotide exit trigger conformational changes that result in the decrease of energetic barriers to maltose translocation towards the cytoplasm, with a concomitant increase of the energy barrier in the periplasmic side of the pore, contributing for the irreversibility of the process. We also identified key residues that aid in positioning and orientation of maltose, as well as a novel binding pocket for maltose in MalG. Additionally, ATP hydrolysis leads to conformations similar to the nucleotide-free state. This study shows the contribution of ATP hydrolysis and nucleotide exit in the transport cycle, shedding light on ABC type I importer mechanisms.

Enhancing the dispersibility of multiwalled carbon nanotubes within starch-based films by the use of ionic surfactants.

The incorporation of carbon-based nanomaterials into biopolymer matrix, to provide mechanical reinforcement and to obtain electrically conductive bionanocomposites, requires the homogeneous dispersion of the fillers. Herein, it is investigated the influence of surfactant structures on the dispersibility of multiwalled carbon nanotubes (MWNT) within starch matrix. Three different ionic surfactants, sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB) and sodium cholate (SC), are employed to disperse the MWNT. Films with MWNT-SC show better dispersibility and an increase of about 75% of tensile strength and 60% of Young's modulus compared with films using MWNT-SDS and MWNT-CTAB. Nevertheless, MWNT functionalized with CTAB impart the highest values of antioxidant activity (scavenging activity around 30% in 1.5 h) and electrical conductivity (σ =14.75 S/m) to starch matrix. The properties of starch-based films can be tailored according to the physical adsorption of each surfactant on MWNT surface and/or the interfacial interaction of the surfactant with starch chains.

Nanocomposites Prepared from Carbon Nanotubes and the Transition Metal Dichalcogenides WS2 and MoS2 via Surfactant-Assisted Dispersions as Electrocatalysts for Oxygen Reactions.

Fuel cells are emerging devices as clean and renewable energy sources, provided their efficiency is increased. In this work, we prepared nanocomposites based on multiwalled carbon nanotubes (MWNTs) and transition metal dichalcogenides (TMDs), namely WS2 and MoS2, and evaluated their performance as electrocatalysts for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), relevant to fuel cells. The one- and two-dimensional (1D and 2D) building blocks were initially exfoliated and non-covalently functionalized by surfactants of opposite charge in aqueous media (tetradecyltrimethylammonium bromide, TTAB, for the nanotubes and sodium cholate, SC, for the dichalcogenides), and thereafter, the three-dimensional (3D) MoS2@MWNT and WS2@MWNT composites were assembled via surfactant-mediated electrostatic interactions. The nanocomposites were characterized by scanning electron microscopy (SEM) and structural differences were found. WS2@MWNT and MoS2@MWNT show moderate ORR performance with potential onsets of 0.71 and 0.73 V vs. RHE respectively, and diffusion-limiting current densities of -1.87 and -2.74 mA·cm-2, respectively. Both materials present, however, better tolerance to methanol crossover when compared to Pt/C and good stability. Regarding OER performance, MoS2@MWNT exhibits promising results, with η10 and jmax of 0.55 V and 17.96 mA·cm-2, respectively. The fabrication method presented here is cost-effective, robust and versatile, opening the doors for the optimization of electrocatalysts' performance.

Tocilizumab in SARS-COVID19 following postoperative laparoscopic transhiatal esophagectomy for the adenocarcinoma of esophagogastric tumor: A case report.

INTRODUCTION AND IMPORTANCE: Esophagectomy for esophageal cancer is one of the most challenging surgical procedures, with high rates of morbidity, especially from respiratory complications. SARS-COVID19 represents a health threat nowadays. Peri-operative SARS-COVID19 infection after esophagectomy might negatively affect the postoperative outcomes. The use of tocilizumab as an alternative to reduce the inflammatory response in SARS-COVID19 is an option that has not been described in the literature after esophagectomy. CASE PRESENTATION: A SARS-COVID19-vaccinated (CORONAVAC) 73-year-old man with pulmonary emphysema, coronary artery disease, previous asymptomatic pulmonary embolism, and adenocarcinoma of the esophagogastric junction tumor was submitted to laparoscopic transhiatal esophagectomy (ypT2N0M0) after perioperative neoadjuvant chemotherapy. He was also infected with SARS-COVID19, confirmed by PCR test at the 14th postoperative day. During follow-up, mild hypoxemia persisted without evidence of infection except for SARS-COVID19, and a high-flow cannula was required to maintain oxygenation. Tocilizumab was administered following high parameters of a high-flow cannula, and invasive mechanical ventilation was avoided. DISCUSSION: Besides of the risk of secondary infection, after administration of tocilizumab, the parameters of oxygen supplementation were systematically reduced, and he stayed in the ICU for seven days. He was discharged from the ward six days later. He developed late cervical anastomotic leakage, which was treated with conservative therapy. CONCLUSION: Although the patient had high-risk comorbidities, esophagectomy, and SARS-COVID19 infection, the use of tocilizumab was safe and improved the pulmonary recovery.

Autonomic and cardiovascular consequences resulting from experimental hemorrhagic stroke in the left or right intermediate insular cortex in rats.

Damage to the insular cortex (IC) results in serious cardiovascular consequences and evidence indicates that the characteristics are lateralized. However, a study comparing the effects of focal experimental hemorrhage between IC sides was never performed. We compared the cardiovascular, autonomic and cardiac changes produced by focal experimental hemorrhage (ICH) into the left (L) or right (R) IC. Wistar rats were submitted to microinjection of autologous blood (ICH) or saline (n = 6 each side/group) into the R or L IC. Blood pressure (BP), heart rate (HR) and renal sympathetic activity (RSNA) were recorded. Measurements of calcium transient and sarcoplasmic Ca2+ ATPase expression in cardiomyocytes were performed. ICH increased baseline HR (Δ:L-ICH 452 ± 13 vs saline 407 ± 11 bpm; R-ICH 450 ± 7 vs saline 406 ± 8 bpm, P < 0.05) without changing BP. HR was restored to baseline levels after i.v. atenolol. Strikingly, ICH rats presented a reduced baseline RSNA (Δ:L-ICH 122 ± 4 vs saline 148 ± 11 spikes/s; R-ICH 112 ± 5 vs saline 148 ± 7 spikes/s, P < 0.05). After 24 h of ICH we observed a marked increase in cardiac ectopies and this number was greater after ICH R-IC. Heart weight, calcium amplitude and SERCA expression were reduced only in ICH R-IC. Focal stroke into IC can alter the cardiac and renal autonomic control. Damage to the R-IC produces a greater number of arrhythmias and changes in calcium dynamics in cardiac cells indicating that the cardiovascular consequences are hemisphere-dependent. These findings confirm asymmetry for cardiac autonomic control at the IC and help to understand the cardiac and renal implications observed after specific side cortical damage.

Gemini surfactants as efficient dispersants of multiwalled carbon nanotubes: Interplay of molecular parameters on nanotube dispersibility and debundling.

Surfactants have been widely employed to debundle, disperse and stabilize carbon nanotubes in aqueous solvents. Yet, a thorough understanding of the dispersing mechanisms at molecular level is still warranted. Herein, we investigated the influence of the molecular structure of gemini surfactants on the dispersibility of multiwalled carbon nanotubes (MWNTs). We used dicationic n-s-n gemini surfactants, varying n and s, the number of alkyl tail and alkyl spacer carbons, respectively; for comparisons, single-tailed surfactant homologues were also studied. Detailed curves of dispersed MWNT concentration vs. surfactant concentration were obtained through a stringently controlled experimental procedure, allowing for molecular insight. The gemini are found to be much more efficient dispersants than their single-tailed homologues, i.e. lower surfactant concentration is needed to attain the maximum dispersed MWNT concentration. In general, the spacer length has a comparatively higher influence on the dispersing efficiency than the tail length. Further, scanning electron microscopy imaging shows a sizeable degree of MWNT debundling by the gemini surfactants in the obtained dispersions. Our observations also point to an adsorption process that does not entail the formation of micelle-like aggregates on the nanotube surface, but rather coverage by individual molecules, among which the ones that seem to be able to adapt best to the nanotube surface provide the highest efficiency. These studies are relevant for the rational design and choice of optimal dispersants for carbon nanomaterials and other similarly water-insoluble materials.

Interactions of a non-fluorescent fluoroquinolone with biological membrane models: A multi-technique approach.

Fluoroquinolones are antibiotics which act by penetrating into bacterial cells and inhibiting enzymes related to DNA replication, and metal complexes of these drugs have recently been investigated as one approach to counteracting bacterial resistance. In this work, we apply a multi-technique approach to studying the partition coefficient (Kp) for the non-fluorescent third-generation fluoroquinolone sparfloxacin or its copper-complex with lipid membrane models of Gram-negative bacteria. The techniques investigated are UV-vis absorption and (19)F NMR spectroscopies together with quenching of a fluorescent probe present in the lipids (using steady-state and time-resolved methods). (19)F NMR spectroscopy has previously been used to determine the Kp values of fluorinated drugs but in the case of sparfloxacin did not yield useful data. However, similar Kp values for sparfloxacin or its copper-complex were obtained for the absorption and fluorescence quenching methods confirming the usefulness of a multi-technique approach. The Kp values measured for sparfloxacin were significantly higher than those found for other fluoroquinolones. In addition, similar Kp values were found for sparfloxacin and copper-complex suggesting that in contrast to other fluoroquinolones hydrophobic diffusion occurs readily for both of these molecules.