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The possibility of developing a multichannel optical chemical sensor, based on molecularly imprinted polymers (MIPs) and surface plasmon resonance (SPR) in a D-shaped multimode plastic optical fiber (POF), is presented by two cascaded SPR-POF-MIP sensors with different thicknesses of the gold layer. The low cost, the high selectivity and sensitivity of the SPR-POF-MIP platforms and the simple and modular scheme of the optical interrogation layout make this system a potentially suitable on-line multi-diagnostic tool. As a proof of principle, the possibility of simultaneous determination of two important analytes, dibenzyl disulfide (DBDS) and furfural (2-FAL), in power transformer oil was investigated. Their presence gives useful indication of underway corrosive or ageing processes in power transformers, respectively. Preliminarily, the dependence of the performance of the D-shaped optical platform on the gold film thickness has been studied, comparing two platforms with 30 nm and 60 nm thick gold layers. It has been found that the resonance wavelengths are different on platforms with gold layer of different thickness, furthermore when MIPs are present on the gold as receptors, the performances of the platforms are similar in the two considered sensors. Keywords: Cascaded multianalyte detection, Surface plasmon resonance, Dibenzyl disulfide, Furfural (furan-2-carbaldehyde), Molecularly imprinted polymers, Plastic optical fibers

Background: The assessment of coronary microvascular dysfunction (CMD) using invasive methods is a field of growing interest, however the preferred method remains debated. Bolus and continuous thermodilution are commonly used methods, but weak agreement has been observed in patients with angina with non-obstructive coronary arteries (ANOCA). This study examined their agreement in revascularized acute coronary syndromes (ACS) and chronic coronary syndromes (CCS) patients. Objective: To compare bolus thermodilution and continuous thermodilution indices of CMD in revascularized ACS and CCS patients and assess their diagnostic agreement at pre-defined cut-off points. Methods: Patients from two centers underwent paired bolus and continuous thermodilution assessments after revascularization. CMD indices were compared between the two methods and their agreements at binary cut-off points were assessed. Results: Ninety-six patients and 116 vessels were included. The mean age was 64 ± 11 years, and 20 (21 %) were female. Overall, weak correlations were observed between the Index of Microcirculatory Resistance (IMR) and continuous thermodilution microvascular resistance (Rµ) (rho = 0.30p = 0.001). The median coronary flow reserve (CFR) from continuous thermodilution (CFRcont) and bolus thermodilution (CFRbolus) were 2.19 (1.76–2.67) and 2.55 (1.50–3.58), respectively (p

Computational free energy-based methods have the potential to significantly improve throughput and decrease costs of protein design efforts. Such methods must reach a high level of reliability, accuracy, and automation to be effectively deployed in practical industrial settings in a way that impacts protein design projects. Here, we present a benchmark study for the calculation of relative changes in protein-protein binding affinity for single point mutations across a variety of systems from the literature, using free energy perturbation (FEP+) calculations. We describe a method for robust treatment of alternate protonation states for titratable amino acids, which yields improved correlation with and reduced error compared to experimental binding free energies. Following careful analysis of the largest outlier cases in our dataset, we assess limitations of the default FEP+ protocols and introduce an automated script which identifies probable outlier cases that may require additional scrutiny and calculates an empirical correction for a subset of charge-related outliers. Through a series of three additional case study systems, we discuss how Protein FEP+ can be applied to real-world protein design projects, and suggest areas of further study., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ‘J.M.S., D.A.C., J.C.K.E., and L.W. are employees of Schrödinger; B.H. is a consultant for and is on the Scientific Advisory Board of Schrödinger, Inc.; R.A.F. has a significant financial stake in, is a consultant for, and is on the Scientific Advisory Board of Schrödinger, Inc. H.A., S.M.G., R.G., S.G., L.D.M., J.C.M., R.B.D., D.G.R., A.S., T.W., and A.B. are employees of AstraZeneca’., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Parkinson's disease (PD) is the second most prevalent neurodegenerative condition after Alzheimer's disease and it represents one of the fastest emerging neurological diseases worldwide. PD is usually diagnosed after the third decade of life with symptoms like tremors at rest and muscle stiffness. Rapid Eye Movement sleep behavioral disorder (RBD) is another disorder that is caused by a loss of typical muscle relaxation during sleep with a lot of motor activity. Usually, RBD is strongly associated with PD. Recent studies have demonstrated that PD reduces the life expectancy of patients to 10 and 20 years after being diagnosed. In addition, delayed diagnosis and treatment of these neurological disorders have significant socio-economic impacts on patients, their partners and on the general public. Often, it is not clear about PD associated financial burdens both in low and high-income countries. On the other hand, PD triggers neurological variations that affect differences in the dopamine transporter (DAT) and in glucose metabolism. Therefore, positron emission tomography (PET) using specific DAT radiotracers and fluorine-18 labeled desoxyglucose (FDG) has being considered a key imaging technique that could be applied clinically for the very early diagnosis of RBD and in PD. However, a few myths about PET is that it is very expensive. Here, we looked at the cost of treatment of PD and RBD in relation to early PET imaging. Our finding suggests that PET imaging might also be a cost sparing diagnostic option in the management of patients with PD and RBD, not only for first world countries as it is the case now but also for the third world countries. Therefore, PET is a cost-effective imaging technique for very early diagnostic of RBD and PD., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Cigarette smoking is a modifiable risk factor associated with formation and rupture of intracranial aneurysms (IAs). Cytochrome P450 2A6 (CYP2A6) is the main enzyme implied in catabolism of nicotine and xenobiotics, giving rise to oxidative stress products. Our study investigated the associations between specific single-nucleotide polymorphisms (SNPs) in the CYP2A6 gene and the presence of sporadic IAs in a cluster of Italian patients, as well as their rupture regarding cigarette smoking habit., Methods: Three hundred and thirty-one Italian patients with sporadic IAs were recruited in a single institution. We recorded data on clinical onset with subarachnoid hemorrhage (SAH) and smoking habit. Genetic analysis was performed with a standard procedure on peripheral blood samples: CYP2A6 ∗1B2, CYP2A6 ∗2, and CYP2A6 ∗14 SNPs were analyzed in the study group along with 150 healthy control subjects. Statistical analysis was conducted according to genetic association study guidelines., Results: In the patient cohort, the frequency of aSAH was significantly higher in current smokers (P < 0.001; OR=17.45), regardless of the pattern of CYP2A6 SNPs. There was a correlation between IA rupture and cigarette smoking in patients with the heterozygous CYP2A6 ∗1B2 allele (P < 0.001; OR=15.47). All patients carrying the heterozygous CYP2A6 ∗14 allele had an aSAH event (100%), regardless of smoking habit, although this correlation was not statistically significant (P = 1)., Conclusions: According to our findings, a cigarette smoker carrying a fully active CYP2A6 enzyme (heterozygous ∗1B2 allele) may have an increased risk of IA rupture compared to those with functionally less active variants: further investigation on a larger sample is needed to verify this result. The role of the heterozygous CYP2A6 ∗14 allele in aSAH is yet to be clarified., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: The bleeding risk and outcome of pregnant women harboring intracranial arteriovenous malformations are still unclear, and no consensus has been achieved on management timing and strategy., Methods: We searched PubMed, MEDLINE, and EMBASE from 1990 to 2022 for studies evaluating the bleeding risk and the outcome of women with intracranial arteriovenous malformations. Our primary end point was the hemorrhage rate. The secondary end points were pregnancy outcome and treatment safety for the mother and the fetus., Results: Nine studies reporting on 2426 women were included. The overall hemorrhage rate in untreated women was 2.6%. The rate of first bleeding during pregnancy and postpartum was greater than the respective fertile period in unpregnant women (11% vs. 6.7%). The risk of first bleeding was greater in the II and III trimesters (4.5% and 2.9%), while was lower during delivery and puerperium (0.1% and 0.2%). The majority of the women did not report any complications after pregnancy and early postpartum death occurred in 4.1% of cases. The overall miscarriage rate was 12.4%., Conclusions: Women harboring intracranial arteriovenous malformations appear to have a greater risk of hemorrhage during pregnancy. There is an increased bleeding risk in the later stages of gestation, whereas delivery and puerperium are less risky phases. Outcomes are relatively good for the mother, with low rates of mortality and unfavorable sequelae, but there is a risk of miscarriage for the fetus. Intervention should be undertaken prophylactically before pregnancy or during early gestation if possible. For pregnant women who deferred treatment, multidisciplinary management is advised., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Surgical indications for cerebral cavernous malformations (CCMs) remain significantly center- and surgeon-dependent; available grading systems are potentially limited, as they do not include epileptologic and radiologic data. Several experienced authors proposed a new grading system for CCM and the first group of patients capable of providing its statistical validation was analyzed., Methods: A retrospective series of 289 CCMs diagnosed between 2008 and 2021 was collected in a shared anonymous database among 9 centers. The new grading system ranges from -1 to 10. For each patient with cortical and cerebellar cavernous malformations the grading system was applied, and a retrospective outcome analysis was performed. We proposed a score of 4 as a cutoff for surgical indication., Results: Operated patients with a score ≥4 were grouped with non-operated patients with a score <4, as they constituted the group that received correct treatment according to the new grading system. Patients with a score ≥4, who underwent surgery and had an improved outcome, were compared to patients with a score ≥4 who were not operated (P = 0.04), and to patients with a score <4 who underwent surgery (P < 0.001)., Conclusions: This preliminary statistical analysis demonstrated that this new grading would be applicable in surgical reality. The cutoff score of 4 correctly separated the patients who could benefit from surgical intervention from those who would not. The outcome analysis showed that the treated patients in whom the grading system has been correctly applied have a better outcome than those in whom the grading system has not been applied., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Healthcare workers (HCWs) are highly exposed to SARS-CoV-2 infection given their specific tasks. The IgG-IgM serological assay has demonstrated good accuracy in early detection in symptomatic patients, but its role in the diagnosis of asymptomatic patients is uncertain. The aim of our study was to assess IgM and IgG prevalence in sera in a large cohort of HCWs previously subjected to Nasopharyngeal swab test (NST) after accurate risk assessment due to positive COVID-19 patient exposure during an observation period of 90 days., Methods: 2407 asymptomatic HCWs that had close contact with COVID-19 patients in the period between April 8th and June 7th were screened with NST based on the RT-PCR method. In parallel, they underwent large-scale chemiluminescence immunoassays involving IgM-IgG serological screening to determine actual viral spread in the same cohort., Results: During the 90-day observation period, 18 workers (0.75%) resulted positive for SARS-CoV-2 infection at the NST, whereas the positivity rates for IgM and IgG were 11.51% and 2.37%, respectively (277 workers). Despite high specificity, serological tests were inadequate for detecting SARS-CoV-2 infection in patients with previous positive NST results (IgM and IgG sensitivities of 27.78% and 50.00%, respectively)., Conclusions: These findings indicate a widespread low viral load of SARS-CoV-2 among hospital workers. However, serological screening showed very low sensitivity with respect to NST in identifying infected workers, and negative IgG and IgM results should not exclude the diagnosis of COVID-19. IgG-IgM chemiluminescence immunoassays could increase the diagnosis of COVID-19 only in association with NST, and this association is considered helpful for decision-making regarding returning to work., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: To determine the prevalence of SARS-CoV-2 infection among exposed healthcare workers (HCWs) after preventive protocol implementation., Methods: A total of 5750 HCWs were included in the study. Those in contact with COVID-19 patients were allocated into a high-risk or a low-risk group based on contact type (PPE- or non-PPE-protected); high-risk workers underwent nasopharyngeal swab tests, while among low-risk workers, swab tests were carried out only for symptomatic workers (active surveillance). The prevalence was determined by real-time reverse transcriptase-polymerase chain reaction on nasopharyngeal samples., Results: 3570 HCWs had contact with 1065 COVID-19 patients. Among them, 3494 were subjected to active surveillance (low-risk group); 2886 (82.60%) were subjected to a swab test; and 15 were positive (0.52%). Seventy-six HCWs (2.13% of exposed) were included in the high-risk group, and a swab test was mandatory for each participant. Overall, 66 (86.84% of high-risk) were negative, and 10 were positive (13.16%), resulting in a higher risk of infection than in the low-risk group [OR = 29.00; 95% CI:12.56-66.94; p < 0.0001]., Conclusion: To date, the SARS-CoV-2 infection prevalence is 0.70% among exposed HCWs and 0.435% among all HCWs working at the examined university hospital. The correct use of PPE and the early identification of symptomatic workers are essential factors to avoiding nosocomial clusters., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background and Objective: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has consistently changed medical practice throughout specialties, regardless of their contribution in facing the disease itself. We surveyed neurosurgeons worldwide to investigate the situation they are experiencing., Methods: A 17-question, web-based survey was administered to neurosurgeons worldwide through the World Federation of Neurosurgical Societies and the Neurosurgery Cocktail from March 28 to April 5, 2020, by web link or e-mail invitation. Questions were divided into 3 subgroups: general information, health system organization, and institutional plans for the SARS-CoV-2 outbreak. Collected data were initially elaborated using SurveyMonkey software. Country-specific data were extracted from the World Health Organization website. Statistical analysis was performed using R, version 3.6.3., Results: Of the 446 respondents, most were from Italy (20%), India (19%), and Pakistan (5%). Surgical activity was significantly reduced in most centers (79%) and dedicated in-hospital routes were created for patients with SARS-CoV-2 (58%). Patient screening was performed only when there were symptoms (57%) and not routinely before surgery (18%). The preferred methods included a nasopharyngeal swab and chest radiograph. Health professionals were rarely screened (20%) and sometimes, even if SARS-CoV-2 positive, were asked to work if asymptomatic (26%). Surgical planning was changed in most institutions (92%), whereas indications were modified for nonurgent procedures (59%) and remained unchanged for subarachnoid hemorrhages (85%)., Conclusions: Most neurosurgeons worldwide reported work reorganization and practices that respond to current international guidelines. Differences in practice might be related to the perception of the pandemic and significant differences in the health systems. Sharing data and experiences will be of paramount importance to address the present moment and challenges in the near future., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Lytic polysaccharide monooxygenases (LPMOs) are industrial enzymes which are gaining use in second generation bioethanol production from lignocellulose by acting in synergy with glycoside hydrolases. Here we present the X-ray crystal structure of an AA9 fungal LPMO from Aspergillus fumigatus and a variant which has been shown to have better performance at elevated temperatures. Based on the structures, thermal denaturation data and theoretical calculations, we provide a suggestion for the structural basis of the improved stability., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Theoretical, computational, and experimental studies have suggested the existence of solvation barriers in protein unfolding and denaturation processes. These barriers are related to the finite size of water molecules and can be envisioned as arising from the asynchrony between water penetration and breakup of internal interactions. Solvation barriers have been proposed to play roles in protein cooperativity and kinetic stability; therefore, they may be expected to be subject to natural selection. We study the thermal denaturation, in the presence and in the absence of chemical denaturants, of triosephosphate isomerases (TIMs) from three different species: Trypanosoma cruzi, Trypanosoma brucei, and Leishmania mexicana. In all cases, denaturation was irreversible and kinetically controlled. Surprisingly, however, we found large differences between the kinetic denaturation parameters, with T. cruzi TIM showing a much larger activation energy value (and, consequently, much lower room-temperature, extrapolated denaturation rates). This disparity cannot be accounted for by variations in the degree of exposure to solvent in transition states (as measured by kinetic urea m values) and is, therefore, to be attributed mainly to differences in solvation-barrier contributions. This was supported by structure-energetics analyses of the transition states and by application of a novel procedure to estimate from experimental data the solvation-barrier impact at the entropy and free-energy levels. These analyses were actually performed with an extended protein set (including six small proteins plus seven variants of lipase from Thermomyces lanuginosus and spanning a wide range of activation parameters), allowing us to delineate the general trends of the solvation-barrier contributions. Overall, this work supports that proteins sharing the same structure and function but belonging to different organisms may show widely different solvation barriers, possibly as a result of different levels of the selection pressure associated with cooperativity, kinetic stability, and related factors.

Subtilisins represent a large class of microbial serine proteases. To date, there are three-dimensional structures of proteinaceous inhibitors from three families in complex with subtilisins in the Protein Data Bank. All interact with subtilisin via an exposed loop covering six interacting residues. Here we present the crystal structure of the complex between the Bacillus lentus subtilisin Savinase and the barley alpha-amylase/subtilisin inhibitor (BASI). This is the first reported structure of a cereal Kunitz-P family inhibitor in complex with a subtilisin. Structural analysis revealed that BASI inhibits Savinase in a novel way, as the interacting loop is shorter than loops previously reported. Mutational analysis showed that Thr88 is crucial for the inhibition, as it stabilises the interacting loop through intramolecular interactions with the BASI backbone.

The clearance of seven different ligands from the deeply buried active-site of Torpedo californica acetylcholinesterase is investigated by combining multiple copy sampling molecular dynamics simulations, with the analysis of protein-ligand interactions, protein motion and the electrostatic potential sampled by the ligand copies along their journey outwards. The considered ligands are the cations ammonium, methylammonium, and tetramethylammonium, the hydrophobic methane and neopentane, and the anionic product acetate and its neutral form, acetic acid. We find that the pathways explored by the different ligands vary with ligand size and chemical properties. Very small ligands, such as ammonium and methane, exit through several routes. One involves the main exit through the mouth of the enzyme gorge, another is through the so-called back door near Trp84, and a third uses a side door at a direction of approximately 45 degrees to the main exit. The larger polar ligands, methylammonium and acetic acid, leave through the main exit, but the bulkiest, tetramethylammonium and neopentane, as well as the smaller acetate ion, remain trapped in the enzyme gorge during the time of the simulations. The pattern of protein-ligand contacts during the diffusion process is highly non-random and differs for different ligands. A majority is made with aromatic side-chains, but classical H-bonds are also formed. In the case of acetate, but not acetic acid, the anionic and neutral form, respectively, of one of the reaction products, specific electrostatic interactions with protein groups, seem to slow ligand motion and interfere with protein flexibility; protonation of the acetate ion is therefore suggested to facilitate clearance. The Poisson-Boltzmann formalism is used to compute the electrostatic potential of the thermally fluctuating acetylcholinesterase protein at positions actually visited by the diffusing ligand copies. Ligands of different charge and size are shown to sample somewhat different electrostatic potentials during their migration, because they explore different microscopic routes. The potential along the clearance route of a cation such as methylammonium displays two clear minima at the active and peripheral anionic site. We find moreover that the electrostatic energy barrier that the cation needs to overcome when moving between these two sites is small in both directions, being of the order of the ligand kinetic energy. The peripheral site thus appears to play a role in trapping inbound cationic ligands as well as in cation clearance, and hence in product release., (Copyright 2000 Academic Press.)