Silver-based bimetallic nanozyme fabrics with peroxidase-mimic activity for urinary glucose detection.

The enhanced catalytic properties of bimetallic nanoparticles have been extensively investigated. In this study, bimetallic Ag-M (M = Au, Pt, or Pd) cotton fabrics were fabricated using a combination of electroless deposition and galvanic replacement reactions, and improvement in their peroxidase-mimicking catalytic activity compared to that of the parent Ag fabric was studied. The Ag-Pt bimetallic nanozyme fabric, which showed the highest catalytic activity and ability to simultaneously generate hydroxyl (•OH) and superoxide (O2•-) radicals, was assessed as a urine glucose sensor. This nanozyme fabric sensor could directly detect urinary glucose in the pathophysiologically relevant high millimolar range without requiring sample predilution. The sensor could achieve performance on par with that of the current clinical gold standard assay. These features of the Ag-Pt nanozyme sensor, particularly its ability to avoid interference effects from complex urinary matrices, position it as a viable candidate for point-of-care urinary glucose monitoring.

Understanding motivations behind medical student involvement in COVID-19 pandemic relief efforts.

BACKGROUND: Although students were removed from patient-facing settings at the beginning of the COVID-19 pandemic due to concerns of burdening teaching physicians and depleting personal protective equipment, some leaders suggest students can be effectively utilized when personnel resources may be scarce. There have been narrative discussions surrounding medical student involvement, but no studies exploring the attitudes of these students. The authors aim to quantify the degree to which factors influenced a medical student's decision to or to not volunteer during the pandemic and to characterize medical students' attitudes towards medical professionals' duty to serve in a pandemic. METHODS: The authors developed and tested a secure web-based survey before distribution to students at 23 different US allopathic medical schools that did not graduate medical students early to aid in pandemic efforts between April and June 2020. Of the 599 students who completed the survey, 65.5% self-identified as female and were on average 25.94 years old (SD = 2.5). Multiple comparisons were made based on volunteer status. Ordinal scale questions were compared with the Mann Whitney U test, and the Chi-Squared test was used for categorical variables using R version 3.62. RESULTS: 67.6% of students volunteered in pandemic relief activities and a majority of those students volunteered in non-patient-facing roles. Community service, new skills, and time commitment were top 3 influencing factors for students who volunteered, while risk to other, time commitment, and risk to self were top 3 influencing factors for students who chose not to volunteer. Compared to other specialties, students interested in primary care specialties agreed to a greater degree that physicians have a duty to serve in pandemic relief efforts. CONCLUSIONS: Medical students who volunteered cited self-serving factors and altruistic values as significant motivators. Students who did not volunteer were significantly more concerned with risks of COVID-19 exposure. However, medical students in general agreed that students should be allowed to volunteer in COVID-19 related relief efforts. As large areas of the United States continue to experience increases in COVID-19 cases, institutions should involve medical students in balancing the level of acceptable risk with the educational benefits.

Bimetallic nanozyme mediated urine glucose monitoring through discriminant analysis of colorimetric signal.

The ability to detect glucose concentrations in human urine offers a non-invasive approach to monitor changes in blood glucose, kidney health and vascular complications associated with diabetes. We show the potential of employing catalytically active nanoparticles directly grown on textiles to produce a dose-dependent colorimetric sensor for glucose. We use a galvanic replacement (GR) reaction for the synthesis of bimetallic nanoparticles. Here, Cu nanoparticles act as a sacrificial template that undergoes a spontaneous electroless GR reaction when exposed to metal ions of gold, silver, platinum, and palladium to form bimetallic Cu-M nanoparticles (M = Au, Ag, Pt, or Pd). The evaluation of their intrinsic peroxidase-mimicking catalytic activity ("nanozyme") in comparison to that of the Cu nanozyme revealed that the bimetallic systems show a higher catalytic rate with the Cu-Pt nanozyme showing the highest catalytic efficiency. This property of the Cu-Pt nanozyme was then utilized to detect glucose in human urine using the glucose oxidase enzyme as a molecular recognition element. A key outcome of our study is the ability to detect urine glucose without requiring sample dilution which is an advantage over the gold standard GOx-POx method and significantly more reliable performance over commercial urine glucose dipsticks. The difference in the intensity of the colorimetric response between different glucose concentrations further allowed this sensor system to be combined with digital imaging tools for multivariate analysis.

Non-invasive detection of glucose in human urine using a color-generating copper NanoZyme.

Renal complications are long-term effect of diabetes mellitus where glucose is excreted in urine. Therefore, reliable glucose detection in urine is critical. While commercial urine strips offer a simple way to detect urine sugar, poor sensitivity and low reliability limit their use. A hybrid glucose oxidase (GOx)/horseradish peroxidase (HRP) assay remains the gold standard for pathological detection of glucose. A key restriction is poor stability of HRP and its suicidal inactivation by hydrogen peroxide, a key intermediate of the GOx-driven reaction. An alternative is to replace HRP with a robust inorganic enzyme-mimic or NanoZyme. While colloidal NanoZymes show promise in glucose sensing, they detect low concentrations of glucose, while urine has high (mM) glucose concentration. In this study, a free-standing copper NanoZyme is used for the colorimetric detection of glucose in human urine. The sensor could operate in a biologically relevant dynamic linear range of 0.5-15 mM, while showing minimal sample matrix effect such that glucose could be detected in urine without significant sample processing or dilution. This ability could be attributed to the Cu NanoZyme that for the first time showed an ability to promote the oxidation of a TMB substrate to its double oxidation diimine product rather than the charge-transfer complex product commonly observed. Additionally, the sensor could operate at a single pH without the need to use different pH conditions as used during the gold standard assay. These outcomes outline the high robustness of the NanoZyme sensing system for direct detection of glucose in human urine. Graphical abstract.

Revisiting the Value of Drains After Low Anterior Resection for Rectal Cancer: a Multi-institutional Analysis of 996 Patients.

BACKGROUND: Intraoperative pelvic drains are often placed during low anterior resection (LAR) to evacuate postoperative fluid collections and identify/control potential anastomotic leaks. Our aim was to assess the validity of this practice. METHODS: Patients from the US Rectal Cancer Consortium (2007-2017) who underwent curative-intent LAR for a primary rectal cancer were included. Patients were categorized as receiving a closed suction drain intraoperatively or not. Primary outcomes were superficial surgical site infection (SSI), deep SSI, intraabdominal abscess, anastomotic leak, and need for secondary drain placement. Three subgroup analyses were conducted in patients who received neoadjuvant chemoradiation, had a diverting loop ileostomy (DLI), and had low anastomoses < 6 cm from the anal verge. RESULTS: Of 996 patients 67% (n = 551) received a drain. Drain patients were more likely to be male (64 vs 54%), have a smoking history (25 vs 19%), have received neoadjuvant chemoradiation (73 vs 61%), have low tumors (56 vs 36%), and have received a DLI (80 vs 71%) (all p < 0.05). Drains were associated with an increased anastomotic leak rate (14 vs 8%, p = 0.041), although there was no difference in the need for a secondary drainage procedure to control the leak (82 vs 88%, p = 0.924). These findings persisted in all subset analyses. Drains were not associated with increased superficial SSI, deep SSI, or intraabdominal abscess in the entire cohort or each subset analysis. Reoperation (12 vs 10%, p = 0.478) and readmission rates (28 vs 31%, p = 0.511) were similar. CONCLUSIONS: Although not associated with increased infectious complications, intraoperatively placed pelvic drains after low anterior resection for rectal cancer are associated with an increase in anastomotic leak rate and no reduction in the need for secondary drain placement or reoperation. Routine drainage appears to be unnecessary.

The impact of the COVID-19 pandemic on children with autism spectrum disorders.

In the unprecedented disruption and social isolation of the COVID-19 pandemic, families around the world are faced with questions of how their children can thrive in these conditions. On top of the ubiquitous challenges for all children, this public health crisis imparts unique difficulties for children with special health needs. We identify children with Autism Spectrum Disorder (ASD) as being particularly vulnerable to negative impacts of the COVID-19 pandemic. In this paper, we examine why children with ASD are uniquely vulnerable, recommend strategies to mitigate these stressors for children with ASD and their parents, explore the potential challenges of reintegration into society as conditions improve, and examine the obligations of healthcare and community stakeholders to support these families.

Evaluation and comparison of histologic changes and implant survival in extraction sites immediately grafted with two different xenografts: A randomized clinical pilot study.

OBJECTIVES: The purpose of this prospective, single-center randomized pilot study was to histologically evaluate and compare vital bone development in premolar and molar-extraction sites grafted with two different bovine-derived xenografts. The secondary outcome of interest was implant survival in the grafted sites. MATERIALS AND METHODS: Adult patients in need of at least two tooth extractions were enrolled. A paired design was used; each patient received at least one of each type of graft at different sites. Each extraction site was randomized to one of two xenograft treatment groups. A resorbable membrane was always placed, and primary intention soft tissue closure was achieved. Four months later, implants were placed and a trephine drill was used to remove bone cores for histologic and histomorphometric analysis. RESULTS: Sixteen patients with 40 extraction sites were enrolled; 20 sites were grafted with one type of xenograft and 20 with another. Mean patient age was 53.5 years, and 65% of patients were male. Evaluation of bone core samples taken from grafted sites showed no significant difference in the mean value of percentage of new bone formation between the different grafted sites (33.4% and 32.4%, p = .76). Cumulative implant survival was 97.5% at the 24-month follow-up visit. CONCLUSION: Within the limitations of this pilot study, no statistically significant differences in new bone growth between sites grafted with two different types of xenograft were found. Both graft materials promoted the formation of new bone and provided osseous support for implant placement after socket grafting.

Dynamic interactions between peroxidase-mimic silver NanoZymes and chlorpyrifos-specific aptamers enable highly-specific pesticide sensing in river water.

With growing environmental and health concerns over persistent organic compounds such as organophosphates, regulatory bodies have imposed strict regulations for their use and monitoring in water bodies. Although conventional analytical tools exist for the detection of organophosphorus pesticides, new strategies need to be developed to fulfil the ASSURED (affordable, sensitive, specific, user-friendly, rapid, equipment-free and deliverable to end users) criteria of the World Health Organisation. One such strategy is to employ the ability of certain nanoparticles to mimic the enzymatic activity of natural enzymes to develop optical sensors. We show that the intrinsic peroxidase-mimic NanoZyme activity of tyrosine-capped silver nanoparticles (Ag-NanoZyme) can be exploited for highly specific and rapid detection of chlorpyrifos, an organophosphorus pesticide. The underlying working principle of the proposed aptasensor is based on the dynamic non-covalent interaction of the chlorpyrifos specific aptamer (Chl) with the NanoZyme (sensor probe) vs. the pesticide target (analyte). The incorporation of the Chl aptamer ensures high specificity leading to a colorimetric response specifically in the presence of chlorpyrifos, while the sensor remains unresponsive to other pesticides from organophosphate and non-organophosphate groups. The robustness of the sensor to work directly in environmental samples was established by evaluating its ability to detect chlorpyrifos in river water samples. The excellent recovery rates demonstrate the sensor robustness, while the simplicity, and rapid sensor response (2 min) to detect the presence of chlorpyrifos highlights the capabilities of the proposed colorimetric sensing system.

Genome-wide engineering of an infectious clone of herpes simplex virus type 1 using synthetic genomics assembly methods.

Here, we present a transformational approach to genome engineering of herpes simplex virus type 1 (HSV-1), which has a large DNA genome, using synthetic genomics tools. We believe this method will enable more rapid and complex modifications of HSV-1 and other large DNA viruses than previous technologies, facilitating many useful applications. Yeast transformation-associated recombination was used to clone 11 fragments comprising the HSV-1 strain KOS 152 kb genome. Using overlapping sequences between the adjacent pieces, we assembled the fragments into a complete virus genome in yeast, transferred it into an Escherichia coli host, and reconstituted infectious virus following transfection into mammalian cells. The virus derived from this yeast-assembled genome, KOSYA, replicated with kinetics similar to wild-type virus. We demonstrated the utility of this modular assembly technology by making numerous modifications to a single gene, making changes to two genes at the same time and, finally, generating individual and combinatorial deletions to a set of five conserved genes that encode virion structural proteins. While the ability to perform genome-wide editing through assembly methods in large DNA virus genomes raises dual-use concerns, we believe the incremental risks are outweighed by potential benefits. These include enhanced functional studies, generation of oncolytic virus vectors, development of delivery platforms of genes for vaccines or therapy, as well as more rapid development of countermeasures against potential biothreats.

Incorporation of the Kaposi's sarcoma-associated herpesvirus capsid vertex-specific component (CVSC) into self-assembled capsids.

Self-assembly of herpesvirus capsids can be accomplished in heterologous expression systems provided all six capsid proteins are present. We have demonstrated the assembly of icosahedral Kaposi's sarcoma-associated herpesvirus (KSHV) capsids in insect cells using the baculovirus expression system. Using this self-assembly system we investigated whether we could add additional capsid associated proteins and determine their incorporation into the assembled capsid. We chose the capsid vertex-specific component (CVSC) proteins encoded by open reading frames (ORFs) 19 and 32 to test this. This complex sits on the capsid vertex and is important for capsid maturation in herpesvirus-infected cells. Co-immunoprecipitation assays were used to initially confirm a bi-molecular interaction between ORF19 and ORF32. Both proteins also precipitated the triplex proteins of the capsid shell (ORF26 and ORF62) as well as the major capsid protein (ORF25). Capsid immunoprecipitation assays revealed the incorporation of ORF19 as well as ORF32 into assembled capsids. Similar experiments also showed that the incorporation of each protein occurred independent of the other. These studies reveal biochemically how the KSHV CVSC interacts with the capsid shell.