Virus surrogates throughout a full-scale advanced water reuse system.

Water reuse as an alternative water supply is increasing throughout the world due to water stress and scarcity; however, there are no standard practices for monitoring virus pathogens in such systems. This study aimed to identify suitable surrogates for virus fate, transport, and removal throughout a water reuse scheme. Various microbial targets (11 viruses, two phage, and three bacteria) were monitored using molecular and culture methods across all treatment stages in a wastewater reclamation facility and advanced water treatment facility. Criteria were established for identifying suitable surrogates, which included reliable detection, observable fate and transport, calculable log-reduction values (LRVs), correlations with other targets, and various morphological types. In total, five viruses (PMMoV, AiV, GII NoV, AdV, FRNA GII) met these stringent criteria and were suggested as potential virus surrogates. These surrogates enabled successful comparison of assigned versus actual LRVs throughout a water reuse scheme. Results suggest that virus pathogens are effectively removed throughout water reuse treatment and the suggested surrogates can be utilized for monitoring treatment performance and ensuring public health safety. This study provides a framework that water utilities across the world can reference for establishing virus monitoring practices.

SARS-CoV-2 genetic material is removed during municipal wastewater treatment and is undetectable after advanced treatment.

The aim of this study was to establish whether SARS-CoV-2 genetic material is detectable after municipal wastewater treatment and to verify its expected removal from purified water that is reclaimed for potable reuse. Viral loads of SARS-CoV-2 (N1 and N2 genes) were monitored in raw influent wastewater (sewage) entering a water reclamation facility and in subsequent advanced treatment. Despite the large viral RNA load in raw sewage during peak COVID-19 outbreaks, substantial amounts of SARS-CoV-2 genetic material were removed during the conventional wastewater treatment process. Further, SARS-CoV-2 genetic material was undetectable after advanced purification. This confirms that potable reuse is resilient against high viral loads which are expected results given the advanced degree of wastewater and water treatment. Findings from this study may enhance public perception of the safety of potable water reuse; however, it should also be noted that studies to date worldwide indicate no evidence of SARS-CoV-2 transmission via water, and the CDC does not consider fecal waste or wastewaters as a source of exposure.

Responsive self-assembly of tectoRNAs with loop-receptor interactions from the tetrahydrofolate (THF) riboswitch.

Naturally occurring RNAs are known to exhibit a high degree of modularity, whereby specific structural modules (or motifs) can be mixed and matched to create new molecular architectures. The modular nature of RNA also affords researchers the ability to characterize individual structural elements in controlled synthetic contexts in order to gain new and critical insights into their particular structural features and overall performance. Here, we characterized the binding affinity of a unique loop-receptor interaction found in the tetrahydrofolate (THF) riboswitch using rationally designed self-assembling tectoRNAs. Our work suggests that the THF loop-receptor interaction has been fine-tuned for its particular role as a riboswitch component. We also demonstrate that the thermodynamic stability of this interaction can be modulated by the presence of folinic acid, which induces a local structural change at the level of the loop-receptor. This corroborates the existence of a THF binding site within this tertiary module and paves the way for its potential use as a THF responsive module for RNA nanotechnology and synthetic biology.

Multiplex Aptamer Discovery through Apta-Seq and Its Application to ATP Aptamers Derived from Human-Genomic SELEX.

Laboratory-evolved RNAs bind a wide variety of targets and serve highly diverse functions, including as diagnostic and therapeutic aptamers. The majority of aptamers have been identified using in vitro selection (SELEX), a molecular evolution technique based on selecting target-binding RNAs from highly diverse pools through serial rounds of enrichment and amplification. In vitro selection typically yields multiple distinct motifs of highly variable abundance and target-binding affinities. The discovery of new aptamers is often limited by the difficulty of characterizing the selected motifs, because testing of individual sequences tends to be a tedious process. To facilitate the discovery of new aptamers within in vitro selected pools, we developed Apta-Seq, a multiplex analysis based on quantitative, ligand-dependent 2' acylation of solvent-accessible regions of the selected RNA pools, followed by reverse transcription (SHAPE) and deep sequencing. The method reveals, in a single sequencing experiment, the identity, structural features, and target dissociation constants for aptamers present in the selected pool. Application of Apta-Seq to a human genomic pool enriched for ATP-binding RNAs yielded three new aptamers, which together with previously identified human aptamers suggest that ligand-binding RNAs may be common in mammals.

Predictors and outcomes of non-adherence in patients receiving maintenance hemodialysis.

PURPOSE: Predictors of and outcomes associated with non-adherent behavior among patients on chronic hemodialysis (HD) have been incompletely elucidated. We conducted a post hoc analysis of data from the SMILE trial to identify patient factors associated with non-adherence to dialysis-related treatments and the associations of non-adherence with clinical outcomes. METHODS: We defined non-adherence as missed HD and abbreviated HD. We used negative binomial regression to model the associations of demographic and clinical factors with measures of non-adherence, and negative binomial and Cox regression to analyze the associations of non-adherence with hospitalizations and mortality, respectively. RESULTS: We followed 286 patients for up to 24 months. Factors independently associated with missing HD included Tuesday/Thursday/Saturday HD schedule [incident rate ratio (IRR) 1.85, p < 0.01], current smoking (IRR 2.22, p < 0.01), higher pain score (IRR 1.04, p < 0.01), lower healthy literacy (IRR 3.01, p < 0.01), lower baseline quality of life (IRR 0.89, p = 0.01), and younger age (IRR 1.35, p < 0.01). Factors independently associated with abbreviating HD included dialysis vintage (IRR 1.07, p < 0.01), higher pain score (IRR 1.02, p < 0.01), current non-smoking (IRR 1.32, p = 0.03), and younger age (IRR 1.22, p < 0.01). Abbreviating HD was independently associated with an increased number of total (IRR 1.70, p < 0.01) and ESRD-related (IRR 1.66, p < 0.01) hospitalizations, while missing HD was independently associated with mortality (HR 2.36, p = 0.04). CONCLUSIONS: We identified several previously described and novel factors independently associated with non-adherence to HD-related treatments, and independent associations of non-adherence with hospitalization and mortality. These findings should inform the development and implementation of interventions to improve adherence and reduce health resource utilization.

Acceptance of Antidepressant Treatment by Patients on Hemodialysis and Their Renal Providers.

BACKGROUND AND OBJECTIVES: Depression is common in patients receiving chronic hemodialysis but seems to be ineffectively treated. We investigated the acceptance of antidepressant treatment by patients on chronic hemodialysis and their renal providers. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: As part of a clinical trial of symptom management in patients on chronic hemodialysis conducted from 2009 to 2011, we assessed depression monthly using the Patient Health Questionnaire 9. For depressed patients (Patient Health Questionnaire 9 score ≥10), trained nurses generated treatment recommendations and helped implement therapy if patients and providers accepted the recommendations. We assessed patients' acceptance of recommendations, reasons for refusal, and provider willingness to implement antidepressant therapy. We analyzed data at the level of the monthly assessment. RESULTS: Of 101 patients followed for ≤12 months, 39 met criteria for depression (Patient Health Questionnaire 9 score ≥10 on one or more assessments). These 39 patients had depression on 147 of 373 (39%) monthly assessments. At 103 of these 147 (70%) assessments, patients were receiving antidepressant therapy, and at 51 of 70 (70%) assessments, patients did not accept nurses' recommendations to intensify treatment. At 44 assessments, patients with depression were not receiving antidepressant therapy, and in 40 (91%) instances, they did not accept recommendations to start treatment. The primary reason that patients refused the recommendations was attribution of their depression to an acute event, chronic illness, or dialysis (57%). In 11 of 18 (61%) instances in which patients accepted the recommendation, renal providers were unwilling to provide treatment. CONCLUSIONS: Patients on chronic hemodialysis with depression are frequently not interested in modifying or initiating antidepressant treatment, commonly attributing their depression to a recent acute event, chronic illness, or dialysis. Renal providers are often unwilling to modify or initiate antidepressant therapy. Future efforts to improve depression management will need to address these patient- and provider-level obstacles to providing such care.

Established and Emerging Strategies in the Treatment of Chronic Kidney Disease.

Chronic kidney disease (CKD) is a common condition that has become a significant public health concern. The mainstay therapeutic approach to CKD is based on renin-angiotensin system blockade as well as blood pressure and glycemic control. Despite these interventions, the management of CKD remains suboptimal, with a large proportion of the CKD population progressing to end-stage renal disease. Newer strategies for the treatment of CKD have emerged over the past years focusing on decreasing inflammation and delaying the development of fibrosis. Despite promising results in experimental models and small randomized studies, adequately powered randomized trials are required to evaluate the benefits and risks of these therapies in the CKD population. In this review, we discuss the evidence behind, and gaps in our knowledge of, established therapies as well as newer potential strategies for managing CKD, concentrating on interventions that currently are being evaluated in randomized studies.

Chemistry and Biology of Self-Cleaving Ribozymes.

Self-cleaving ribozymes were discovered 30 years ago, but their biological distribution and catalytic mechanisms are only beginning to be defined. Each ribozyme family is defined by a distinct structure, with unique active sites accelerating the same transesterification reaction across the families. Biochemical studies show that general acid-base catalysis is the most common mechanism of self-cleavage, but metal ions and metabolites can be used as cofactors. Ribozymes have been discovered in highly diverse genomic contexts throughout nature, from viroids to vertebrates. Their biological roles include self-scission during rolling-circle replication of RNA genomes, co-transcriptional processing of retrotransposons, and metabolite-dependent gene expression regulation in bacteria. Other examples, including highly conserved mammalian ribozymes, suggest that many new biological roles are yet to be discovered.

Discovering human RNA aptamers by structure-based bioinformatics and genome-based in vitro selection.

In vitro selection and structure-based searches have emerged as useful techniques for the discoveries of structurally complex RNAs with high affinity and specificity toward metabolites. Here, we focus on the design of a human genomic library that serves as the DNA template for in vitro selection of RNA aptamers. In addition, the structural solutions obtained from the in vitro selection can be used for structure-based searches for discovery of analogous aptamers in various genomic databases.

Crystal structure of Leishmania major peroxidase and characterization of the compound i tryptophan radical.

The parasitic protozoa Leishmania major produces a peroxidase (L. major peroxidase; LmP) that exhibits activities characteristic of both yeast cytochrome c peroxidase (CCP) and plant cytosolic ascorbate peroxidase (APX). One common feature is a key Trp residue, Trp(208) in LmP and Trp(191) in CCP, that is situated adjacent to the proximal His heme ligand in CCP, APX, and LmP. In CCP, Trp(191) forms a stable cationic radical after reaction with H(2)O(2) to form Compound I; in APX, the radical is located on the porphyrin ring. In order to clarify the role of Trp(208) in LmP and to further probe peroxidase structure-function relationships, we have determined the crystal structure of LmP and have studied the role of Trp(208) using electron paramagnetic resonance spectroscopy (EPR), mutagenesis, and enzyme kinetics. Both CCP and LmP have an extended section of ß structure near Trp(191) and Trp(208), respectively, which is absent in APX. This region provides stability to the Trp(191) radical in CCP. EPR of LmP Compound I exhibits an intense and stable signal similar to CCP Compound I. In the LmP W208F mutant, this signal disappears, indicating that Trp(208) forms a stable cationic radical. In LmP conversion of the Cys(197) to Thr significantly weakens the Compound I EPR signal and dramatically lowers enzyme activity. These results further support the view that modulation of the local electrostatic environment controls the stability of the Trp radical in peroxidases. Our results also suggest that the biological role of LmP is to function as a cytochrome c peroxidase.

Nódulos parotídeos: experiencia en la República de Haití / Parotid nodules: experience in the Republic of Haiti

INTRODUCCIÓN. Las enfermedades de las glándulas salivales ocupan un lugar relevante entre las patologías quirúrgicas de la cabeza y el cuello. El objetivo de este trabajo fue presentar la experiencia del tratamiento quirúrgico de tumores parotídeos benignos del lóbulo superficial, mediante anestesia local, en pacientes de la Republica de Haití atendidos como parte de la colaboración médica cubana en ese país. MÉTODOS. Se realizó un estudio prospectivo en pacientes con nódulos parotídeos, atendidos en la República de Haití entre los años 2005 y 2006. Según su naturaleza, los nódulos fueron agrupados en inflamatorios, neoplásicos y otros. Para el tratamiento quirúrgico se utilizó la anestesia local con lidocaína al 1 por ciento, combinando el método infiltrativo y el bloqueo de campo. Se consultaron 149 pacientes con nódulos parotídeos, el mayor porcentaje de los cuales correspondió a procesos inflamatorios (68,0 por ciento) y en 29 pacientes (19,0 por ciento) se comprobó la presencia de nódulos neoplásicos. Las complicaciones fueron seroma (3 casos; 33,3 por ciento), hematoma (2 casos; 22,2 por ciento), y 4 pacientes no presentaron complicaciones. CONCLUSIONES. El abordaje quirúrgico con anestesia local probó ser una alternativa válida cuando el cirujano no cuenta con los recursos que convencionalmente se movilizan para el tratamiento quirúrgico de estos casos(AU)

INTRODUCTION. The diseases of the salivary glands occupy an important place among the surgical pathologies of the neck and the head. The aim of this paper was to present the experience of the surgical treatment of benign parotid tumors of the superficial lobule by local anesthesia in Haitian patients attended as part of the Cuban medical collaboration in this country. METHODS. A prospective study was carried out in patients with parotid nodules attended in the Republic of Haiti from 2005 to 2006. According to their nature, the nodules were grouped into inflammatory, neoplastic and others. Local anesthesia with lidocaine 1 percent was used for the surgical treatment, combining the infiltrative method and the field block. 149 patients with parotid nodules were seen. The highest percentage corresponded to inflammatory processes (68.0 percent). The presence of neoplastic nodules was confirmed in 29 patients (19.0 percent). The complications were seroma (3 cases; 33.3 percent) and hematoma (2 cases; 22.2 percent). Four patients did not present complications. CONCLUSIONS. The surgical approach with local anesthesia proved to be a valid alternative when the surgeon does not have the resources that are usually used for the surgical treatment of these cases(AU)