A study survey on molnupiravir treatment in COVID-19 patients at home in Ninh Thuan province, Vietnam.

OBJECTIVE: Molnupiravir (MOV) is an oral antiviral drug that received use authorization in Vietnam for the treatment of mild COVID-19 (F0). There was a need to develop alternative approaches that allowed patients to access medication, decongest hospitals, clinics, and facilities, and protect people from infection. During the COVID-19 crisis, the Ninh Thuan Health Authorities implemented the home delivery of medication by community health workers. This study conducted in collaboration with two important Italian entities [the Aldo Moro University of Bari City and the 118 Department of Territorial Emergency System (118 SET) of Taranto City] aimed to evaluate the implementation of home delivery F0 treatment package assessing the rate of infection recovering during the coronavirus pandemic in Ninh Thuan province, Vietnam. PATIENTS AND METHODS: A convergent mixed methods research, based on a longitudinal study with quantitative research and qualitative assessments, evaluated four implementation outcomes: the feasibility, fidelity, coverage, sustainability, and effectiveness of the initiative. Data sources included routinely collected data, a telephonic survey of patients, an analysis of set-up and recurrent costs, as well as descriptive exploratory qualitative and quantitative analysis. RESULTS: After taking the MOV for 5 days, only 35 out of the initial 400 F0 patients remained positive, while 365 patients (91.2%) were negative (CT≥30). Whilst, the successful rate after using the drug during the course accounted for 99.85% and 100% after the entire treatment course, without any death. After 5 days of taking the drug, a positive test result (CT<30) was associated with age group ≥60 (OR=2.7) and comorbidities (OR=3.0) (p<0.05) compared to negative and positive results (CT≥30). Negative factors impacting F0 at home include a shortage of healthcare workers, inadequate supply of thermometers and SpO2 meters, and insufficient financial support for healthcare workers. CONCLUSIONS: MOV caused a reduction in the risk of hospitalization or death in mild COVID-19 patients, and molnupiravir was also found to be well tolerated and safe without any major adverse events during the administration period.

Hydrodynamic Models of G-Quadruplex Structures.

G-quadruplexes are noncannonical four-stranded DNA or RNA structures formed by guanine-rich repeating sequences. Guanine nucleotides can hydrogen bond to form a planar tetrad structure. Such tetrads can stack to form quadruplexes of various molecularities with a variety of types of single-stranded loops joining the tetrads. High-resolution structures may be obtained by X-ray crystallography or NMR spectroscopy for quadruplexes formed by short (≈25 nt) sequences but these methods have yet to succeed in characterizing higher order quadruplex structures formed by longer sequences. An integrated computational and experimental approach was implemented in our laboratory to obtain structural models for higher order quadruplexes that might form in longer telomeric or promoter sequences. In our approach, atomic-level models are built using folding principles gleaned from available high-resolution structures and then optimized by molecular dynamics. The program HYDROPRO is then used to construct bead models of these structures to predict experimentally testable hydrodynamic properties. Models are validated by comparison of these properties with measured experimental values obtained by analytical ultracentrifugation or other biophysical tools. This chapter describes our approach and practical procedures.

An investigation of G-quadruplex structural polymorphism in the human telomere using a combined approach of hydrodynamic bead modeling and molecular dynamics simulation.

Guanine-rich oligonucleotides can adopt noncanonical tertiary structures known as G-quadruplexes, which can exist in different forms depending on experimental conditions. High-resolution structural methods, such as X-ray crystallography and NMR spectroscopy, have been of limited usefulness in resolving the inherent structural polymorphism associated with G-quadruplex formation. The lack of, or the ambiguous nature of, currently available high-resolution structural data, in turn, has severely hindered investigations into the nature of these structures and their interactions with small-molecule inhibitors. We have used molecular dynamics in conjunction with hydrodynamic bead modeling to study the structures of the human telomeric G-quadruplex-forming sequences at the atomic level. We demonstrated that molecular dynamics can reproduce experimental hydrodynamic measurements and thus can be a powerful tool in the structural study of existing G-quadruplex sequences or in the prediction of new G-quadruplex structures.

Calculation of hydrodynamic properties for G-quadruplex nucleic acid structures from in silico bead models.

Nucleic acids enriched in guanine bases can adopt unique quadruple helical tertiary structures known as G-quadruplexes. G-quadruplexes have emerged as attractive drug targets as many G-quadruplex-forming sequences have been discovered in functionally critical sites within the human genome, including the telomere, oncogene promoters, and mRNA processing sites. A single G-quadruplex-forming sequence can adopt one of many folding topologies, often resulting in a lack of a single definitive atomic-level resolution structure for many of these sequences and a major challenge to the discovery of G-quadruplex-selective small molecule drugs. Low-resolution techniques employed to study G-quadruplex structures (e.g., CD spectroscopy) are often unable to discern between G-quadruplex structural ensembles, while high-resolution techniques (e.g., NMR spectroscopy) can be overwhelmed by a highly polymorphic system. Hydrodynamic bead modeling is an approach to studying G-quadruplex structures that could bridge the gap between low-resolution techniques and high-resolution molecular models. Here, we present a discussion of hydrodynamic bead modeling in the context of studying G-quadruplex structures, highlighting recent successes and limitations to this approach, as well as an example featuring a G-quadruplex structure formed from the human telomere. This example can easily be adapted to the investigation of any other G-quadruplex-forming sequences.

Not all G-quadruplexes are created equally: an investigation of the structural polymorphism of the c-Myc G-quadruplex-forming sequence and its interaction with the porphyrin TMPyP4.

G-quadruplexes, DNA tertiary structures highly localized to functionally important sites within the human genome, have emerged as important new drug targets. The putative G-quadruplex-forming sequence (Pu27) in the NHE-III(1) promoter region of the c-Myc gene is of particular interest as stabilization of this G-quadruplex with TMPyP4 has been shown to repress c-Myc transcription. In this study, we examine the Pu27 G-quadruplex-forming sequence and its interaction with TMPyP4. We report that the Pu27 sequence exists as a heterogeneous mixture of monomeric and higher-order G-quadruplex species in vitro and that this mixture can be partially resolved by size exclusion chromatography (SEC) separation. Within this ensemble of configurations, the equilibrium can be altered by modifying the buffer composition, annealing procedure, and dialysis protocol thereby affecting the distribution of G-quadruplex species formed. TMPyP4 was found to bind preferentially to higher-order G-quadruplex species suggesting the possibility of stabilization of the junctions of the c-Myc G-quadruplex multimers by porphyrin end-stacking. We also examined four modified c-Myc sequences that have been previously reported and found a narrower distribution of G-quadruplex configurations compared to the parent Pu27 sequence. We could not definitively conclude whether these G-quadruplex structures were selected from the original ensemble or if they are new G-quadruplex structures. Since these sequences differ considerably from the wild-type promoter sequence, it is unclear whether their structures have any actual biological relevance. Additional studies are needed to examine how the polymorphic nature of G-quadruplexes affects the interpretation of in vitro data for c-Myc and other G-quadruplexes. The findings reported here demonstrate that experimental conditions contribute significantly to G-quadruplex formation and should be carefully considered, controlled, and reported in detail.

Polymorphism and resolution of oncogene promoter quadruplex-forming sequences.

We report the separation of several quadruplex species formed by ten promoter sequences by Size Exclusion Chromatography (SEC). Modification at the 5' or 3' ends or in loop regions of quadruplex forming sequences has become the standard technique for dealing with quadruplex polymorphism. However, conformations produced employing this method or by other means of artificially shifting the equilibrium may not represent the species that are present in vivo. This method enables an unperturbed view of the structural polymorphism inherent to quadruplex formation. Separation via SEC facilitates studies on quadruplex structure and biophysical properties without the need for sequence modification.