Interfacial Interactions between Nanoplastics and Biological Systems: toward an Atomic and Molecular Understanding of Plastics-Driven Biological Dyshomeostasis

Micro- and nano-plastics (NPs) are found in human milk, blood, tissues, and organs and associate with aberrant health outcomes including inflammation, genotoxicity, developmental disorders, onset of chronic diseases, and autoimmune disorders. Yet, interfacial interactions between plastics and biomolecular systems remain underexplored. Here, we have examined experimentally, in vitro, in vivo, and by computation, the impact of polystyrene (PS) NPs on a host of biomolecular systems and assemblies. Our results reveal that PS NPs essentially abolished the helix-content of the milk protein β-lactoglobulin (BLG) in a dose-dependent manner. Helix loss is corelated with the near stoichiometric formation of β-sheet elements in the protein. Structural alterations in BLG are also likely responsible for the nanoparticle-dependent attrition in binding affinity and weaker on-rate constant of retinol, its physiological ligand (compromising its nutritional role). PS NP-driven helix-to-sheet conversion was also observed in the amyloid-forming trajectory of hen egg-white lysozyme (accelerated fibril formation and reduced helical content in fibrils). Caenorhabditis elegans exposed to PS NPs exhibited a decrease in the fluorescence of green fluorescent protein-tagged dopaminergic neurons and locomotory deficits (akin to the neurotoxin paraquat exposure). Finally, in silico analyses revealed that the most favorable PS/BLG docking score and binding energies corresponded to a pose near the hydrophobic ligand binding pocket (calyx) of the protein where the NP fragment was found to make nonpolar contacts with side-chain residues via the hydrophobic effect and van der Waals forces, compromising side chain/retinol contacts. Binding energetics indicate that PS/BLG interactions destabilize the binding of retinol to the protein and can potentially displace retinol from the calyx region of BLG, thereby impairing its biological function. Collectively, the experimental and high-resolution in silico data provide new insights into the mechanism(s) by which PS NPs corrupt the bimolecular structure and function, induce amyloidosis and onset neuronal injury, and drive aberrant physiological and behavioral outcomes.

Thermodynamic Study of Leaching Conditions of Galena with Citrate Ions and Hydrogen Peroxide as Oxidizing Agent

Galena is the most important mineral for lead production, as it is the main source of lead in the world. Currently, the concentrates of this mineral are mainly treated using pyrometallurgical methods, creating several environmental problems, such as the generation of toxic and greenhouse gases. In addition, these processes involve high energy consumption, which limits their applicability. Hydrometallurgical routes are proposed as alternative processes for obtaining some metals such as silver, copper, gold, etc. The drawback of these processes is that the minerals tend to be passive in aqueous media. To mitigate this issue, researchers have used extreme conditions of pressure and temperature (6 atm. and 155 °C) or the use of very corrosive conditions. In this sense, the use of complexing agents that dissolve the metals of interest has been proposed. Citrate ion is one of the most promising complexing agents for galena leaching, obtaining high percentages of dissolution in relatively short times. Unfortunately, there has not been enough investigation about the concentration optimization of the complexing in the pH range from 5 to 9. In this sense, thermodynamic diagrams, such as the Pourbaix diagrams, are very useful for this purpose. Therefore, in this work, the effects of pH and temperature on the leaching of galena in citrate ion solutions are studied thermodynamically and experimentally. The experimental work was carried out with pure galena samples with a particle size of +149 - 74 µm (-100 + 200 mesh). The results show that higher recoveries were obtained working at a pH of 8 and at temperatures of 30 and 40 °C. The thermodynamic and experimental data demonstrated that the existence of an optimal concentration of citrate ion, due the extraction of lead from galena, has a greater reaction rate at a relatively low initial concentration of 0.3 M. This is due the formation of the complex lead citrate 1 (Pb(cit)-).

Thyroid surgery outcomes at a children's hospital: The value of a multidisciplinary team approach

BACKGROUND

Our purpose is to describe the structure, function and outcomes of our multidisciplinary pediatric thyroid program and to evaluate our experience in comparison to other high-volume centers.

METHODS

We reviewed all thyroid operations performed 10/2012 through 09/2019, and examined number of cases per year, patient demographics, procedures, final diagnoses and results. Primary outcomes were hypoparathyroidism and recurrent laryngeal nerve (RLN) injury at 12 months. Data were analyzed using descriptive statistics and univariate analyses.

RESULTS

We performed 294 thyroid operations on 279 patients. Seventy-nine percent were female. Median age was 15 years (IQR: 12-17). Operations included total thyroidectomy (65%), lobectomy (30%) and completion thyroidectomy (5%). Most common diagnoses were Graves' disease (35%), malignancy (29%), and benign nodule (20%). We developed an evidence-based clinical pathway and conducted weekly multidisciplinary meetings. A clinical data specialist reviewed process and outcome measures routinely. Overall, 6 patients (2.0%) had hypoparathyroidism and 2 (0.7%) had unilateral RLN injury at 12 months. Two of the patients with clinical suspicion of permanent hypoparathyroidism were ultimately weaned off calcium. Both patients with RLN injury had extensive locally advanced malignant disease involving the nerve.

CONCLUSIONS

Our multidisciplinary team achieved excellent long-term outcomes for pediatric thyroid surgery comparable to other high-volume pediatric and adult centers.

OPTN/SRTR 2020 Annual Data Report: VCA

The first vascularized composite allograft (VCA) transplant in the United States was performed in 1998 in a 40-year-old man who received a laryn-geal transplant after experiencing severe trauma to the throat 20 years before. The following VCA was a hand transplant in 1999 in a 37-year-old man who lost his left hand 13 years before. Since then, the field of VCA transplantation has made significant strides. On July 3, 2014, the Or gan Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) oversight of VCA procurement and transplant in the United States went into effect. In the last decade, the number of candidates listed for and transplanted with VCA has increased. While patient demographic data, whether listed candidates or patients undergoing VCA transplant, is limited by sample size, the trend is a predominance toward a young/middle-aged, White population. Overall outcomes data have been promising, with the vast majority of VCA transplants resulting in functioning grafts.

Mitigation of MAFLD in High Fat-High Sucrose-Fructose Fed Mice by a Combination of Genistein Consumption and Exercise Training

PURPOSE

Metabolic dysfunction-associated fatty liver disease (MAFLD) is fueled by escalations in both sedentary behavior and caloric intake and is noted in obese type 2 diabetic (T2DM) patients. This study aimed to examine the effects of exercise and the phytoestrogen genistein in mice fed a high fat (60% fat) high sugar (55% fructose with 45% sucrose), HFHS diet.

METHODS

Male C57BL/6J mice were assigned to five groups: HFHS, HFHS with genistein (600 mg/kg diet, HFHS+Gen), HFHS with moderate exercise (HFHS+Ex), and HFHS with combined genistein and moderate exercise (HFHS-Gen+Ex). Control lean mice were fed standard chow and water. Exercise consisted of 30-minute sessions of treadmill running five days/week for the 12-week study duration. Body weight was assessed weekly. Liver, kidney, fecal pellets and serum were extracted at the end of the study and maintained at -80°C.

RESULTS

After 12 weeks of treatment, mice in the HFHS group had the highest hepatic lipid content. Plasma levels of glucose, insulin, leptin, cholesterol, amylin, and total fat content were significantly elevated in HFHS mice compared to control mice. HFHS feeding increased protein expression of carnitine palmitoyltransferase 1b (CPT-1b isoform) in gastrocnemius, CPT1a, glucose transporter protein 2 (GLUT2), glucocorticoid receptor (GR), and fructose 1,6-bisphosphate 1 (FBP1) expression in liver. Exercise alone had minor effects on these metabolic abnormalities. Genistein alone resulted in improvements in body weight, fat content, amylin, insulin sensitivity, and liver histopathology, GR, FBP1, and acetyl-CoA carboxylase 1 (ACC1). Combination treatment resulted in additional metabolic improvements, including reductions in hepatic lipid content and lipid area, alanine transferase activity, CPT1b, and CPT1a.

CONCLUSION

Our results indicate that a HFHS diet is obesogenic, inducing metabolic perturbations consistent with T2DM and MAFLD. Genistein alone and genistein combined with moderate intensity exercise were effective in reducing MAFLD and the aberrations induced by chronic HFHS feeding.

Environment and coordination of FeMo-co in the nitrogenase metallochaperone NafY

In nitrogenase biosynthesis, the iron-molybdenum cofactor (FeMo–co) is externally assembled at scaffold proteins and delivered to the NifDK nitrogenase component by the NafY metallochaperone. Here we have used nuclear magnetic resonance, molecular dynamics, and functional analysis to elucidate the environment and coordination of FeMo–co in NafY. H¹²¹ stands as the key FeMo–co ligand. Regions near FeMo–co diverge from H¹²¹ and include the η1, α1, α2 helical lobe and a narrow path between H¹²¹ and C¹⁹⁶.

Broadening of NMR resonance spins used to map binding of paramagnetic FeMo–co to the nitrogenase metallocluster escort protein NafY.

Multisystem inflammatory syndrome in children associated with SARS-CoV-2 in a solid organ transplant recipient

We present the case of a 3-year-old female liver transplant recipient with a history of Caroli disease who presented with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcription polymerase chain reaction (RT-PCR) test and was ultimately diagnosed with multisystem inflammatory syndrome in children (MIS-C) complicated by portal vein thrombosis. To the best of our knowledge, this is the first case report of MIS-C in a pediatric solid organ transplant (SOT) recipient. Based on our patient, MIS-C could be a potential complication of Coronavirus disease 2019 (COVID-19) in SOT recipients and may have a negative outcome on transplant graft function.

Gastrojejunal Enteral Tube Serving as a Small Bowel Bezoar Nidus

Gastrojejunal (GJ) tube placement is indicated in the management of gastric feeding-related intolerance. Though uncommon, GJ complications may occur. We present the case of a five-year-old male with congenital heart disease in which image-guided replacement of a GJ tube was unable to be completed due to a mass adhered to the tip of the tube. The subsequent endoscopic evaluation identified the mass as a hair-based bezoar and the tube was successfully removed. The child was subsequently diagnosed with trichotillomania, trichophagia, and pica. This case illustrates the importance of recognizing bezoar formation as a potential complication of GJ enteric tubes, particularly in children with trichophagia and pica.

Thermoelectric properties of antimony selenide hexagonal nanotubes

Antimony selenide (Sb₂Se₃) is a material widely used in photodetectors and relatively new as a possible material for thermoelectric applications. Taking advantage of the new properties after nanoscale fabrication, this material shows great potential for the development of efficient low temperature thermoelectric devices. Here we study the synthesis, the crystal properties and the thermal and thermoelectric transport response of Sb₂Se₃ hexagonal nanotubes (HNT) in the temperature range between 120 and 370 K. HNT have a moderate electrical conductivity ∼10² S m^-1 while maintaining a reasonable Seebeck coefficient ∼430 μV K^-1 at 370 K. The electrical conductivity in Sb₂Se₃ HNT is about 5 orders of magnitude larger and its thermal conductivity one half of what is found in bulk. Moreover, the calculated figure of merit (ZT) at room temperature is the largest value reported in antimony selenide 1D structures.

The utility and promise of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) in the pediatric population: An evidence-based review

Hemorrhage is the main cause of preventable death in both military and civilian trauma, and many of these patients die from non-compressible torso injuries. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a minimally invasive method used for hemodynamic control of the hemorrhaging patient and has been compared to resuscitative thoracotomy (RT) with cross clamping of the aorta. REBOA has received a great deal of attention in recent years for its applicability and promise in adult trauma and non-trauma settings, but its utility in children is mostly unknown. The purpose of this review article is to summarize and consolidate what is currently known about the use of REBOA in children. Some of the challenges in implementing REBOA in children include small vascular anatomy and lack of outcomes data. Although the evidence is limited, there are established instances in the literature of children and adolescents who have undergone endovascular occlusion of the aorta for hemorrhage control with positive outcomes and survival rates equivalent to their adult counterparts. There is a need for further formal evaluation of REBOA in pediatric patients with prospective studies to look at the safety, feasibility and efficacy of the technique. STUDY TYPE: Narrative Literature Review LEVEL OF EVIDENCE: IV.

Determinants of Chest X-Ray Sensitivity for COVID- 19: A Multi-Institutional Study in the United States

Purpose

To evaluate the sensitivity, specificity, and severity of chest x-rays (CXR) and chest CTs over time in confirmed COVID-19+ and COVID-19- patients and to evaluate determinants of false negatives.

Methods

In a retrospective multi-institutional study, 254 RT-PCR verified COVID-19+ patients with at least one CXR or chest CT were compared with 254 age- and gender-matched COVID-19- controls. CXR severity, sensitivity, and specificity were determined with respect to time after onset of symptoms; sensitivity and specificity for chest CTs without time stratification. Performance of serial CXRs against CTs was determined by comparing area under the receiver operating characteristic curves (AUC). A multivariable logistic regression analysis was performed to assess factors related to false negative CXR.

Results

COVID-19+ CXR severity and sensitivity increased with time (from sensitivity of 55% at ≤2 days to 79% at >11 days; p<0.001 for trends of both severity and sensitivity) whereas CXR specificity decreased over time (from 83% to 70%, p=0.02). Serial CXR demonstrated increase in AUC (first CXR AUC=0.79, second CXR=0.87, p=0.02), and second CXR approached the accuracy of CT (AUC=0.92, p=0.11). COVID-19 sensitivity of first CXR, second CXR, and CT was 73%, 83%, and 88%, whereas specificity was 80%, 73%, and 77%, respectively. Normal and mild severity CXR findings were the largest factor behind false-negative CXRs (40% normal and 87% combined normal/mild). Young age and African-American ethnicity increased false negative rates.

Conclusion

CXR sensitivity in COVID-19 detection increases with time, and serial CXRs of COVID-19+ patients has accuracy approaching that of chest CT.

Mutations in the zebrafish hmgcs1 gene reveal a novel function for isoprenoids during red blood cell development

Erythropoiesis is the process by which new red blood cells (RBCs) are formed and defects in this process can lead to anemia or thalassemia. The GATA1 transcription factor is an established mediator of RBC development. However, the upstream mechanisms that regulate the expression of GATA1 are not completely characterized. Cholesterol is 1 potential upstream mediator of GATA1 expression because previously published studies suggest that defects in cholesterol synthesis disrupt RBC differentiation. Here we characterize RBC development in a zebrafish harboring a single missense mutation in the hmgcs1 gene (Vu57 allele). hmgcs1 encodes the first enzyme in the cholesterol synthesis pathway and mutation of hmgcs1 inhibits cholesterol synthesis. We analyzed the number of RBCs in hmgcs1 mutants and their wild-type siblings. Mutation of hmgcs1 resulted in a decrease in the number of mature RBCs, which coincides with reduced gata1a expression. We combined these experiments with pharmacological inhibition and confirmed that cholesterol and isoprenoid synthesis are essential for RBC differentiation, but that gata1a expression is isoprenoid dependent. Collectively, our results reveal 2 novel upstream regulators of RBC development and suggest that appropriate cholesterol homeostasis is critical for primitive erythropoiesis.

Thermoelectric properties and thermal tolerance of indium tin oxide nanowires

Highly crystalline indium tin oxide (ITO) nanowires were grown via a vapor-liquid-solid method, with thermal tolerance up to ∼1300 °C. We report the electric and thermoelectric properties of the ITO nanowires before and after heat treatments and draw conclusions about their applicability as thermoelectric building blocks in nanodevices that can operate in high temperature conditions. The Seebeck coefficient and the thermal and electrical conductivities were measured in each individual nanowire by means of specialized micro-bridge thermometry devices. Measured data was analyzed and explained in terms of changes in charge carrier density, impurities and vacancies due to the thermal treatments.

HPLC Method for Quantification of Caffeine and Its Three Major Metabolites in Human Plasma Using Fetal Bovine Serum Matrix to Evaluate Prenatal Drug Exposure

Caffeine is recognized as the first-line therapeutic agent for apnea of prematurity. The dosage regimen is 10 mg/kg loading dose and 2.5 mg/kg maintenance dose. However, the plasma concentration achieved, not always, is therapeutically useful. It makes necessary to increase the doses to reach plasma concentration up to 30 or 35 μg/mL or even higher to attain therapeutic effect. To study why neonates have these differences, and whether these effects are linked to prenatal caffeine exposure, we had to develop an analytical method for an accurate measurement of caffeine and metabolites concentration. The analysis was carried out using fetal bovine serum (FBS) as biological matrix in a high-performance liquid chromatography with an ultraviolet detector method. This method allows acceptable chromatographic resolution between analytes in 15 minutes. It was validated and proved to be linear in the 0.1-40 µg/mL range for caffeine, paraxanthine, theobromine, and theophylline in the same chromatographic analysis. Accuracy for quality control samples for intra- and interday assays was ranged from 96.5 to 105.2% and 97.1 to 106.2%. Precision had CV no more than 10% in all concentration levels for all analytes. No differences were observed between quantification in human and FBS. This method was applied to quantify plasma drug concentration in mothers and their newborns in a Mexican northeast population. In our study, we confirmed self-reported caffeine maternal intake in 85.2% (n=23); meanwhile, in their newborn's plasma, it was detected only in 78% (n=21). Caffeine plasma concentrations in mother and newborn had a linear relationship, and no differences were observed between groups (mothers versus children). These results suggest that our analytical method and substitution of biological matrix was linear, precise, and accurate for caffeine quantification and could be used for measuring prenatal exposure and let us to study, in the future, concentration differences observed during apnea clinical treatment.

Thermoelectric properties of SnSe nanowires with different diameters

Tin selenide (SnSe) has been the subject of great attention in the last years due to its highly efficient thermoelectricity and its possibilities as a green material, free of Pb and Te. Here, we report for the first time a thermoelectricity and transport study of individual SnSe micro- and nano-wires with diameters in the range between 130 nm and 1.15 μm. X-ray diffraction and transmission electron microscopy analyses confirm an orthorhombic SnSe structure with Pnma (62) symmetry group and 1:1 Sn:Se atomic ratio. Electrical and thermal conductivity and the Seebeck coefficient were measured in each individual nanowire using a specialized suspended microdevice in the 150-370 K temperature range, yielding a thermal conductivity of 0.55 Wm-1 K-1 at room temperature and ZT ~ 0.156 at 370 K for the 130 nm diameter nanowire. The measured properties were correlated with electronic information obtained by model simulations and with phonon scattering analysis. The results confirm these structures as promising building blocks to develop efficient temperature sensors, refrigerators and thermoelectric energy converters. The thermoelectric response of the nanowires is compared with recent reports on crystalline, polycrystalline and layered bulk structures.

EXAFS reveals two Mo environments in the nitrogenase iron-molybdenum cofactor biosynthetic protein NifQ

Mo and Fe K-edge EXAFS analysis of NifQ shows the presence of a [MoFe₃S₄] cluster and a second independent Mo environment that includes Mo-O bonds and Mo-S bonds. Both environments are relevant to FeMo-co biosynthesis and may represent different stages of Mo biochemical transformations catalyzed by NifQ.

Functional analysis of the zebrafish ortholog of HMGCS1 reveals independent functions for cholesterol and isoprenoids in craniofacial development

There are 8 different human syndromes caused by mutations in the cholesterol synthesis pathway. A subset of these disorders such as Smith-Lemli-Opitz disorder, are associated with facial dysmorphia. However, the molecular and cellular mechanisms underlying such facial deficits are not fully understood, primarily because of the diverse functions associated with the cholesterol synthesis pathway. Recent evidence has demonstrated that mutation of the zebrafish ortholog of HMGCR results in orofacial clefts. Here we sought to expand upon these data, by deciphering the cholesterol dependent functions of the cholesterol synthesis pathway from the cholesterol independent functions. Moreover, we utilized loss of function analysis and pharmacological inhibition to determine the extent of sonic hedgehog (Shh) signaling in animals with aberrant cholesterol and/or isoprenoid synthesis. Our analysis confirmed that mutation of hmgcs1, which encodes the first enzyme in the cholesterol synthesis pathway, results in craniofacial abnormalities via defects in cranial neural crest cell differentiation. Furthermore targeted pharmacological inhibition of the cholesterol synthesis pathway revealed a novel function for isoprenoid synthesis during vertebrate craniofacial development. Mutation of hmgcs1 had no effect on Shh signaling at 2 and 3 days post fertilization (dpf), but did result in a decrease in the expression of gli1, a known Shh target gene, at 4 dpf, after morphological deficits in craniofacial development and chondrocyte differentiation were observed in hmgcs1 mutants. These data raise the possibility that deficiencies in cholesterol modulate chondrocyte differentiation by a combination of Shh independent and Shh dependent mechanisms. Moreover, our results describe a novel function for isoprenoids in facial development and collectively suggest that cholesterol regulates craniofacial development through versatile mechanisms.

Integrating Molecular Testing in the Diagnosis and Management of Children with Thyroid Lesions

Thyroid nodules occur in 1-2% of children, and identifying which nodules are malignant is often challenging. Cytologic evaluation facilitates the diagnosis of thyroid lesions (TLs), but in 10-40% of cases the interpretation is indeterminate. Patients with indeterminate diagnoses are often treated with hemithyroidectomy followed by completion thyroidectomy, if cancer is found in the initial specimen. Exposing patients to multiple surgeries increases costs and morbidity. The American Thyroid Association states that a combination of molecular markers is likely to optimize the management of patients with indeterminate cytology. However, few studies have addressed the molecular alterations present in pediatric TL. Twenty-seven thyroid carcinomas from patients 10 to 19 years of age were tested for alterations common in adult TL, including BRAF V600E mutation, RET fusions, and TERT promoter mutations. Mutation-negative cases were subsequently analyzed with a next-generation sequencing (NGS) mutation panel to search for additional targets. Histologic diagnoses included 12 classic papillary thyroid carcinomas (PTCs), 13 follicular variant PTCs, 1 medullary thyroid carcinoma, and 1 follicular carcinoma. Fourteen cases showed lymph node involvement, and 13 cases demonstrated lymphovascular invasion. The BRAF V600E mutation was detected in 10/27 cases, and RET fusions were detected in 6/27 cases. No TERT promoter mutations were identified in any of the cases. The NGS panel revealed additional RET and CTNNB1 pathogenic missense mutations. Our results demonstrate that molecular abnormalities are common in pediatric TLs and suggest that incorporation of molecular testing will be helpful in optimizing patient management.

Diagnostic performance and application of a real-time PCR assay for the detection of Salmonella in fecal samples collected from hospitalized horses with or without signs of gastrointestinal tract disease

The main objective of this study was to assess the diagnostic performance of a real-time polymerase chain reaction (PCR) assay for the detection of Salmonella in fecal samples collected from hospitalized horses with or without signs of gastrointestinal (GI) tract disease. The PCR assay used primers and a probe that targeted the invA gene of Salmonella. Assuming a sensitivity of 100% and a specificity of 96.6%, and a disease prevalence of 2%, 5%, and 10-15% in study horses, the PCR assay had a high (100%) negative predictive value, and a positive predictive value that ranged from 37% in horses without signs of GI disease that tested Salmonella culture-negative, to 60% in horses with signs of GI disease that tested Salmonella culture-negative, to 76-83% in horses with signs of GI disease that tested Salmonella culture-positive. This study provides evidence that the real-time PCR that targets the Salmonella invA gene can be used as a screening test for the detection of Salmonella in feces of hospitalized horses with signs of GI disease. Horses that test PCR-positive can be tested in series using bacteriologic culture to reduce false positive results or to provide additional data (e.g., antibiogram and serotyping data) that can be used to identify potential nosocomial Salmonella infections.

Growth and carcass characteristics of pasture fed LHRH immunocastrated, castrated and intact Bos indicus bulls

The effectiveness of a luteinizing hormone-releasing hormone (LHRH) fusion protein vaccine or surgical castration, at two years of age, on growth and carcass characteristics of Bos indicus bulls was evaluated. Seventy Nelore-cross bulls were divided into three groups: (1) immunized, (2) castrated and (3) intact control. At slaughter (three years of age), intact bulls had higher body weights, ADG, carcass weights, and muscle percentage compared to immunized and surgically castrated animals. Both castrated and immunized animals had greater marbling and percent carcass fat than the intact bulls. Average tenderness scores were inferior for intact bulls compared to immunized and castrated animals, but these differences were not significant (P>0.05). Juiciness, flavor, thawing, nor cooking losses differed significantly among the three groups. Immunocastration was effective in producing carcass traits similar to that of surgical castration. Therefore, immunization with LHRH fusion proteins appears to have practical utility in the management and castration of grazing bulls.