Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 224
Filter
1.
Birth Defects Research ; 115(8):867, 2023.
Article in English | EMBASE | ID: covidwho-20241292

ABSTRACT

Remdesivir (RDV) is an antiviral medication used most recently for the treatment of COVID-19. Although no adverse effects were observed on perinatal parameters in reproductive and development toxicology studies at doses up to four-fold clinical area under the curve (AUC) exposures, some researchers have reported that therapeutic levels of RDV may impair early embryogenesis, as observed by in vitro studies. In addition, the influence of prenatal RDV exposure on maternal IgG transfer in the placenta is still unknown. Administration of RDV in pregnant humanized mouse model (Tg32), which expresses the human Fc gamma receptor and transporter (FCGRT) gene, was used to further evaluate potential effects on IgG transfer and concurrent perinatal endpoints. Animals were dosed daily from gestational days (GDs) 10- 14 with 25 mg/kg RDV (GS-5734) via intravenous injection (n=3-5 per group). Concurrent vehicle control animals were dosed intravenously with 12% sulfobutyl ether- beta-cyclodextrin in water (pH3.5;NaOH/HCl). All animals were administered 2 mg/kg human IgG via intravenous injection on GD 14. Placentae and fetuses were collected from dams on GD 14, 15, 16, and 18 and evaluated using histopathology and qPCR for inflammation markers. No abnormal morphologies (necrosis/apoptosis) of placentae were observed between the concurrent control and RDVdosed groups. Additionally, no differences in maternal body weights were observed. There were no statistically significant differences in placenta weights. There were no statistically significant changes in pregnancy parameters (implantation sites and dead fetuses/litter) and fetal weights between the RDV-dosed group and concurrent controls at GD 14, 15, 16, and 18. No changes were observed in transcript levels of inflammation markers in the RDV-dosed group when compared to the concurrent control group. There was a slightly lower ratio of fetal IgG level to maternal IgG levels in the RDV-dosed group;however, no statistically significant differences were observed between the RDV-dosed group and concurrent controls on GD 14, 15, 16, and 18. Our results suggest that a daily dose of 25 mg/kg RDV on GDs 10-14 in humanized mice did not cause adverse effects on placenta and fetal development. (Funded by the Perinatal Health Center of Excellence: E0300201.).

2.
Journal of the American College of Surgeons ; 236(5 Supplement 3):S3, 2023.
Article in English | EMBASE | ID: covidwho-20236569

ABSTRACT

Introduction: The COVID-19 pandemic caused significant decreases in outpatient procedures, many of which are required before to antireflux operation (ARS). The purpose of this study was to add functional luminal imaging probe (FLIP) to esophagogastroduodenoscopy (EGD) and esophageal pH monitoring to assess its utility in decreasing the need for follow up studies in patients being evaluated for ARS. Method(s): Retrospective observational study was performed on 81 patients being evaluated for GERD who underwent EGD, pH monitoring, and FLIP. Data collected included average distensibility index (DI) at 60 mL, presence of repetitive anterograde or retrograde contractions, hiatal hernia dimensions, pathology results, pH data, and need for follow-up testing. Result(s): Based on FLIP results, HRM was recommended in 35 patients (43.2%). This included 14 patients with DI suggestive of significant esophagogastric junction outflow obstruction, eight of whom completed HRM with four confirmed as achalasia. FLIP results were suspicious for eosinophilic esophagitis (EoE) in four patients of which one was confirmed as EoE on biopsy. Gastric emptying study was felt to be necessary for 11 patients before to ARS. Conclusion(s): FLIP identified patients with possible alternative pathologies including achalasia and EoE that would otherwise be a contraindication to ARS. FLIP at the time of EGD and pH monitoring is useful as it guides the clinical decision on need for additional outpatient procedures, which may be difficult to obtain in pandemic conditions. FLIP was effective at reducing the requirements for further follow-up testing in the majority of patients being evaluated for potential ARS.

3.
Nordic Pulp & Paper Research Journal ; 2023.
Article in English | Web of Science | ID: covidwho-20235231

ABSTRACT

Paper has been used in the field of hygiene for centuries. Tissue papers have low grammage, creped or non-creped surface, and consisting of one or more layers from virgin papers. Toilet paper, which has an important area of use, comes at the beginning of the tissue papers divided into various product groups. Its use has increased even more with the effect of the coronavirus pandemic. Increasing use of toilet paper causes clogging in sewers as solid waste. Because an important and large part of the sewage is composed of cellulosic structures. Therefore, the disintegration of toilet paper is an important issue. The main properties of toilet paper are characterized by grammage, thickness, polymerization degree, softness and wet tensile strength. This study, it was aimed to determine the relationship between the degree of polymerization, thickness, grammage, softness and wet tension strength of toilet papers, which accumulate in the sewer pipes and cause clogging, and their disintegration in tap water and pure water at environment of different pH levels. A great level and positive linear relationship was found between grammage and in disintegration pH9. It was determined a low level and positive relationship with wet tensile strength in disintegration tap water.

4.
Journal of Population Therapeutics and Clinical Pharmacology ; 30(9):e178-e186, 2023.
Article in English | EMBASE | ID: covidwho-20233238

ABSTRACT

Background: At our hospital, people with COVID-19 (coronavirus disease 2019) had a high rate of pulmonary barotrauma. Therefore, the current study looked at barotrauma in COVID-19 patients getting invasive and non-invasive positive pressure ventilation to assess its prevalence, clinical results, and features. Methodology: Our retrospective cohort study comprised of adult COVID-19 pneumonia patients who visited our tertiary care hospital between April 2020 and September 2021 and developed barotrauma. Result(s): Sixty-eight patients were included in this study. Subcutaneous emphysema was the most frequent type of barotrauma, reported at 67.6%;pneumomediastinum, reported at 61.8%;pneumothorax, reported at 47.1%. The most frequent device associated with barotrauma was CPAP (51.5%). Among the 68 patients, 27.9% were discharged without supplemental oxygen, while 4.4% were discharged on oxygen. 76.5% of the patients expired because of COVID pneumonia and its complications. In addition, 38.2% of the patients required invasive mechanical breathing, and 77.9% of the patients were admitted to the ICU. Conclusion(s): Barotrauma in COVID-19 can pose a serious risk factor leading to mortality. Also, using CPAP was linked to a higher risk of barotrauma.Copyright © 2021 Muslim OT et al.

5.
Perfusion ; 38(1 Supplement):186, 2023.
Article in English | EMBASE | ID: covidwho-20233093

ABSTRACT

Objectives: To present a series of immunosuppressed patients (oncohematological disease, congenital immunosuppression, hematopoietic stem cell (HSCT), and solid organ transplant) assisted on ECMO. Method(s): Descriptive, retrospective study (2011-2020) of a cohort of 9 immunosuppressed patients, supported on ECMO. Medical records were reviewed and demographic, clinical, and analytical variables were collected. Result(s): In our series of 9 patients, 5 were male, the median age was 8 years [RIC 3-11 years]. Considering the underlying disease, 6 were oncologic, 1 liver transplant and 2 with congenital immunodeficiency after HSCT. 4 were under active chemotherapy (median 6 days after the last cycle [RIC 5-188]). 6 were admitted due to acute respiratory failure, 3 due to hemodynamic instability (3/9), (one septic shock). The median PEEP was 12 [RIC 9-15] and FiO2 100% (81-100%). 78% (6) required vasoactive drugs (median inotropic score 35 [RIC 0-75]. 40%. 5 had severe neutropenia and/or plateletopenia in the 24 hours prior to ECMO, and alterations in acid-base balance (median pH 7. 1 [RIC 6.9-7.15]. 5 were on multiorgan failure. TPrimary ECMO transport was performed in 4 patients (44%). Cannulation was peripheral in 80% (57% cervical, 43% femoral) and central in 20%;70% VA-ECMO. Median time of assistance was 15 days [RIC 3.5-31.5] in cardiac ECMO (4), and 29 days [RIC 13.5-42] and in pulmonary ECMO (n=5). The median total time of admission was 45 days [RIC 27-59]. 9 had an infection, 2 COVID after HSCT, and 8 bleeding complications, but only one required surgical revision. Renal replacement therapy was used in 5 (median 9 days [RIC 5-34.5]). Other therapies used were polymyxin hemadsorption(2), intratracheal surfactant(2), plasma exchange(1), infusion of mesenchymal cells(1) and specific memory T lymphocytes(2). 4 patients died, 5 survived decannulation, 2 died later, with an overall survival rate to hospital discharge of 33% (3/9). Conclusion(s): Despite having a worse prognosis, ECMO can increase survival in immunosuppressed patients, in situations that are challenging and require a multidisciplinary approach.

6.
Biomedicines ; 11(5)2023 May 11.
Article in English | MEDLINE | ID: covidwho-20242936

ABSTRACT

The global outbreak of SARS-CoV-2/COVID-19 provided the stage to accumulate an enormous biomedical data set and an opportunity as well as a challenge to test new concepts and strategies to combat the pandemic. New research and molecular medical protocols may be deployed in different scientific fields, e.g., glycobiology, nanopharmacology, or nanomedicine. We correlated clinical biomedical data derived from patients in intensive care units with structural biology and biophysical data from NMR and/or CAMM (computer-aided molecular modeling). Consequently, new diagnostic and therapeutic approaches against SARS-CoV-2 were evaluated. Specifically, we tested the suitability of incretin mimetics with one or two pH-sensitive amino acid residues as potential drugs to prevent or cure long-COVID symptoms. Blood pH values in correlation with temperature alterations in patient bodies were of clinical importance. The effects of biophysical parameters such as temperature and pH value variation in relation to physical-chemical membrane properties (e.g., glycosylation state, affinity of certain amino acid sequences to sialic acids as well as other carbohydrate residues and lipid structures) provided helpful hints in identifying a potential Achilles heel against long COVID. In silico CAMM methods and in vitro NMR experiments (including 31P NMR measurements) were applied to analyze the structural behavior of incretin mimetics and SARS-CoV fusion peptides interacting with dodecylphosphocholine (DPC) micelles. These supramolecular complexes were analyzed under physiological conditions by 1H and 31P NMR techniques. We were able to observe characteristic interaction states of incretin mimetics, SARS-CoV fusion peptides and DPC membranes. Novel interaction profiles (indicated, e.g., by 31P NMR signal splitting) were detected. Furthermore, we evaluated GM1 gangliosides and sialic acid-coated silica nanoparticles in complex with DPC micelles in order to create a simple virus host cell membrane model. This is a first step in exploring the structure-function relationship between the SARS-CoV-2 spike protein and incretin mimetics with conserved pH-sensitive histidine residues in their carbohydrate recognition domains as found in galectins. The applied methods were effective in identifying peptide sequences as well as certain carbohydrate moieties with the potential to protect the blood-brain barrier (BBB). These clinically relevant observations on low blood pH values in fatal COVID-19 cases open routes for new therapeutic approaches, especially against long-COVID symptoms.

7.
Int J Environ Sci Technol (Tehran) ; : 1-24, 2022 Jul 27.
Article in English | MEDLINE | ID: covidwho-20243012

ABSTRACT

In this study, four water quality parameters were reviewed at 14 stations of river Ganga in pre-, during and post-lockdown and these parameters were modeled by using different machine learning algorithms. Various mathematical models were used for the computation of water quality parameters in pre-, during and post- lockdown period by using Central Pollution Control Board real-time data. Lockdown resulted in the reduction of Biochemical Oxygen Demand ranging from 55 to 92% with increased concentration of dissolved oxygen at few stations. pH was in range of 6.5-8.5 of during lockdown. Total coliform count declined during lockdown period at some stations. The modeling of oxygen saturation deficit showed supremacy of Thomas Mueller model (R 2 = 0.75) during lockdown over Streeter Phelps (R 2 = 0.57). Polynomial regression and Newton's Divided Difference model predicted possible values of water quality parameters till 30th June, 2020 and 07th August, 2020, respectively. It was found that predicted and real values were close to each other. Genetic algorithm was used to optimize hyperparameters of algorithms like Support Vector Regression and Radical Basis Function Neural Network, which were then employed for prediction of all examined water quality metrics. Computed values from ANN model were found close to the experimental ones (R 2 = 1). Support Vector Regression-Genetic Algorithm Hybrid proved to be very effective for accurate prediction of pH, Biochemical Oxygen Demand, Dissolved Oxygen and Total coliform count during lockdown. Supplementary Information: The online version contains supplementary material available at 10.1007/s13762-022-04423-1.

8.
Am J Health Syst Pharm ; 2023 Jun 06.
Article in English | MEDLINE | ID: covidwho-20239585

ABSTRACT

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

9.
Front Microbiol ; 14: 1190463, 2023.
Article in English | MEDLINE | ID: covidwho-20231823

ABSTRACT

The ongoing SARS-CoV-2 pandemic and the influenza epidemics have revived the interest in understanding how these highly contagious enveloped viruses respond to alterations in the physicochemical properties of their microenvironment. By understanding the mechanisms and conditions by which viruses exploit the pH environment of the host cell during endocytosis, we can gain a better understanding of how they respond to pH-regulated anti-viral therapies but also pH-induced changes in extracellular environments. This review provides a detailed explanation of the pH-dependent viral structural changes preceding and initiating viral disassembly during endocytosis for influenza A (IAV) and SARS coronaviruses. Drawing upon extensive literature from the last few decades and latest research, I analyze and compare the circumstances in which IAV and SARS-coronavirus can undertake endocytotic pathways that are pH-dependent. While there are similarities in the pH-regulated patterns leading to fusion, the mechanisms and pH activation differ. In terms of fusion activity, the measured activation pH values for IAV, across all subtypes and species, vary between approximately 5.0 to 6.0, while SARS-coronavirus necessitates a lower pH of 6.0 or less. The main difference between the pH-dependent endocytic pathways is that the SARS-coronavirus, unlike IAV, require the presence of specific pH-sensitive enzymes (cathepsin L) during endosomal transport. Conversely, the conformational changes in the IAV virus under acidic conditions in endosomes occur due to the specific envelope glycoprotein residues and envelope protein ion channels (viroporins) getting protonated by H+ ions. Despite extensive research over several decades, comprehending the pH-triggered conformational alterations of viruses still poses a significant challenge. The precise mechanisms of protonation mechanisms of certain during endosomal transport for both viruses remain incompletely understood. In absence of evidence, further research is needed.

10.
Research and Teaching in a Pandemic World: The Challenges of Establishing Academic Identities During Times of Crisis ; : 481-496, 2023.
Article in English | Scopus | ID: covidwho-2322931

ABSTRACT

The Ph.D. genre captures the complexity and plurality of practices generally confronting doctoral scholars, creating challenges and at times contributing to wellbeing concerns. The arrival of COVID-19 has exacerbated such challenges with its associated mandatory self-isolation and other imposed measures, leading to explicit and implicit impact on members of the doctoral community. This autoethnographic study draws upon the collective reflections of a group of researchers as they explored practical ways of fostering and supporting mental health and wellbeing within the doctoral community. Our study highlights three aspects for consideration: (a) a holistic understanding of doctoral wellbeing as key, (b) the interconnection between doctoral scholars' and staff members' well-being, and (c) communities serving as avenues to psychological wellness. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

11.
Research and Teaching in a Pandemic World: The Challenges of Establishing Academic Identities During Times of Crisis ; : 361-374, 2023.
Article in English | Scopus | ID: covidwho-2322219

ABSTRACT

The COVID-19 pandemic has shaken research in higher education in unexpected ways (OECD, 2021). While it sped up the transition to online and virtual modes of learning within the academe, it also generated significantly higher levels of anxiety and depression among university-based researchers (Chirikov et al., 2020). Higher education institutions adopted widespread changes in teaching loads and research policy at break-neck speed, often to the dismay of early career researchers and doctoral candidates. This chapter investigates the impact of the global health crisis on the research output and strategies of early career researchers and doctoral candidates at universities around the world. It reviews the literature on the impact of the COVID-19 pandemic on research output and strategies. The chapter also incorporates recent findings from the author's research project, which investigates the long-term impact of the pandemic on academic writing strategies and output among doctoral candidates (following on from results previously published in Cahusac de Caux (2021)). © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

12.
Research and Teaching in a Pandemic World: The Challenges of Establishing Academic Identities During Times of Crisis ; : 303-314, 2023.
Article in English | Scopus | ID: covidwho-2327280

ABSTRACT

The crisis of the COVID-19 pandemic has dramatically changed many academic practices and situations that used to be taken for granted, leaving academia in a state of shock and chaos. As an individual who tried to meet new demands brought by the changing academic environment, I also experienced a sense of crisis. However, as I tried to meet those new demands, I developed new capabilities and employable skills. In this chapter, I will present selected accounts of my personal experiences in academia, both as a Ph.D. candidate and a higher education teacher during the pandemic. Cultural-historical and activity theory concepts, such as the concept of activity and the concept of crisis, are used to provide analytical insights into my experiences. The new insights helped me shift my perception of crises as something negative to opportunities and potential for development. It is argued that the concepts of activity and crisis can be useful conceptual tools to transform our way of perceiving crises and thus find new developmental conditions for ourselves in challenging situations. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

13.
Research and Teaching in a Pandemic World: The Challenges of Establishing Academic Identities During Times of Crisis ; : 37-57, 2023.
Article in English | Scopus | ID: covidwho-2325754

ABSTRACT

COVID-19 has transformed the world in diverse ways, presenting ongoing challenges. One of these challenges has been a profound sense of uncertainty. In this chapter, the authors from India/France and Iran explore their experiences of uncertainty as international students working on their Ph.D.s away from their Australian university. The authors engaged in collaborative autoethnography to present their stories as research poems. Interspersed with interpretations, the poems attempt to unravel the shared and diverse ways in which the authors contextually processed uncertainty. Finally, the authors underscore ways in which university and government actors can further support international Ph.D. students to address their specific needs during and post-pandemic periods. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

14.
International Journal of Endocrinology and Metabolism ; 21(2) (no pagination), 2023.
Article in English | EMBASE | ID: covidwho-2325145

ABSTRACT

Context: The coronavirus disease 2019 (COVID-19) pandemic is still a cause of worldwide health concern. Diabetes and its associated comorbidities are risk factors for mortality and morbidity in COVID-19. Selecting the right antidiabetic drug to achieve optimal glycemic control might mitigate some of the negative impacts of diabetes. Metformin continues to be the most widely administered antidiabetic agent. There is evidence of its beneficial outcome in COVID-19 independent of its glucose-lowering effect. Evidence Acquisition: A thorough literature search was conducted in PubMed, Google Scholar, Scopus, and Web of Science to identify studies investigating metformin in COVID-19. Result(s): Several overlapping mechanisms have been proposed to explain its antiviral properties. It could bring about conformational changes in the angiotensin-converting enzyme-2 receptor and decrease viral entry. The effects on the mammalian target of the rapamycin pathway and cellular pH have been proposed to reduce viral protein synthesis and replication. The immunomodulatory effects of metformin might counter the detrimental effects of hyperinflammation associated with COVID-19. Conclusion(s): These findings call for broader metformin usage to manage hyperglycemia in COVID-19.Copyright © 2023, International Journal of Endocrinology and Metabolism.

15.
Research and Teaching in a Pandemic World: The Challenges of Establishing Academic Identities During Times of Crisis ; : 77-86, 2023.
Article in English | Scopus | ID: covidwho-2325004

ABSTRACT

COVID-19 impacted the world's population irrespective of race, sex, gender, and culture, but did so with varying intensities. People experienced difficulties and uncertainties in different aspects of life;difficulties in aspects that may not have been given the same attention pre-pandemic, especially the area of mental health. Pursuing a Ph.D. itself is a stressful journey and the pandemic made it even more difficult for me, a laboratory-based researcher, due to limited lab access. Self-isolation due to COVID-19 and further unexpected events made the journey even more challenging, more than anyone could have ever expected. In this chapter, I share my experience as an international Ph.D. candidate during the pandemic. I explore my experiences through a process of self-discovery and acceptance of my new self with empathy in connection with mental health associated theories. My experience provides insight to other Ph.D. candidates as they may be able to relate to my journey by reflecting on their own experiences. This chapter also provides some strategies to help future Ph.D. candidates thrive in their research journeys. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

16.
Geohealth ; 7(4): e2022GH000769, 2023 Apr.
Article in English | MEDLINE | ID: covidwho-2322540

ABSTRACT

Climate-induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical constraint, resulting in increased Vibrio spread, exposure, and infection rates, thus facilitating greater Vibrio-human interactions. Multiple efforts have been developed to predict Vibrio exposure and raise awareness of health risks, but most models only use temperature and salinity as prediction factors. This study aimed to better understand the potential effects of temperature and pH on V. vulnificus and V. parahaemolyticus planktonic and biofilm growth. Vibrio strains were grown in triplicate at 25°, 30°, and 37°C in 96 well plates containing Modified Seawater Yeast Extract modified with CaCl2 at pH's ranging from 5 to 9.6. AMiGA software was used to model growth curves using Gaussian process regression. The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the interpolation fit on the MatLab Curve Fitting Toolbox. Different optimal conditions involving temperature and pH were observed for planktonic and biofilm Vibrio growth within- and between-species. This study showed that temperature and pH factors significantly affect Vibrio planktonic growth rates and V. parahaemolyticus biofilm formation. Therefore, pH effects must be added to the Vibrio growth modeling efforts to better predict Vibrio risk in estuarine and coastal zones that can potentially experience the cooccurrence of Vibrio and harmful algal bloom outbreak events.

17.
Journal of Hydrology and Hydromechanics ; 71(2):156-168, 2023.
Article in English | ProQuest Central | ID: covidwho-2320327

ABSTRACT

The root tuber of Pinellia ternata has been used as a traditional therapeutic herbal medicine. It is reported to impart beneficial attributes in recovering COVID-19 patients. To meet an increasing demand of P. ternata, this study is intended to investigate the effects of biochar on the soil hydrological and agronomic properties of two decomposed soils (i.e., completely decomposed granite (CDG) and lateritic soil) for the growth of P. ternata. The plant was grown in instrumented pots with different biochar application rate (0%, 3% and 5%) for a period of three months. Peanut shell biochar inclusion in both soils resulted in reduction of soil hydraulic conductivity and increase in soil water retention capacity. These alterations in hydrological properties were attributed to measured change in total porosity, biochar intra pore and hydrophilic functional groups. The macro-nutrient (i.e., N, P, K, Ca, and Mg) concentration of both soils increased substantially, while the pH and cation exchange capacity levels in the amended soils were altered to facilitate optimum growth of P. ternata. The tuber biomass in biochar amended CDG at all amendment rate increases by up to 70%. In case of lateritic soil, the tuber biomass increased by 23% at only 5% biochar application rate. All treatments satisfied the minimum succinic acid concentration required as per pharmacopoeia standard index. The lower tuber biomass exhibits a higher succinic acid concentration regardless of the soil type used to grow P. ternata. The biochar improved the yield and quality of P. ternata in both soils.

18.
Journal of Biological Chemistry ; 299(3 Supplement):S669, 2023.
Article in English | EMBASE | ID: covidwho-2314260

ABSTRACT

The genomic material of SARS-CoV-2 is a positive-sense single-stranded RNA. SARS-CoV-2 produces non-structural protein 1 (NSP1), which inhibits host cell translation by binding its' N-terminal to the host's 40S ribosomal subunit. Once NSP1 is bound its C-terminal domain folds and binds to the mRNA entry channel. Stem loop 1 (SL1) in the 5'-UTR of the viral mRNA binds to NSP1 to abrogate translation inhibition leading to the expression of viral proteins. SL1 contains a 1 x 2 internal loop that is not seen in other coronaviruses and may be involved in conformational changes that influence SL1-NSP1 interactions. The 1 x 2 internal loop of SL1 contains a putative A*C non-canonical base pair. The U6 snRNA also contains a 1 x 2 internal loop known to undergo conformation changes in response to pH and magnesium ion binding. Here we examine the thermodynamic properties and magnesium binding of the 1 x 2 internal loop of SL1 in varying helical contexts. Thermal denaturation experiments were performed on various DNA and RNA constructs in the presence of 1 M KCl or 10 mM magnesium chloride at a pH of 5.5 and 7. We show that formation of the A+*C base pair and the construct stability in the presence of magnesium ions is dependent on the helical context.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.

19.
Journal of Biological Chemistry ; 299(3 Supplement):S672, 2023.
Article in English | EMBASE | ID: covidwho-2313857

ABSTRACT

Raman spectroscopy probes the vibrational modes of a molecule. In recent years, surface-enhanced Raman spectra (SERS) of oligonucleotides on gold or silver nanoparticles have yielded significantly stronger signals. Raman spectra of DNA are high throughput, quantitative, and label-free and show distinct features created by vibrational modes such as ring deformation, backbone bending, and hydrogen bond stretching. Here we are using gold nanoparticles to probe various structural changes in a short helical DNA designed to mimic SL1 of coronavirus and SL of U6 snRNA. Phosphate buffers containing 1 M KCl or 10 mM magnesium chloride were utilized at two different pH (5.5 and 7). Differences in peak intensity are being observed between canonically paired helical DNA and DNA of similar composition with modifications containing non-canonical A*C base pair. We are comparing ion binding, pH-related, and temperature-variable conditions to observe changes in DNA structures.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.

20.
ACS Appl Mater Interfaces ; 15(6): 7759-7766, 2023 Feb 15.
Article in English | MEDLINE | ID: covidwho-2311054

ABSTRACT

Infectious agents such as viruses pose significant threats to human health, being transmitted via direct contact as well as airborne transmission without direct contact, thus requiring rapid detection to prevent the spread of infectious diseases. In this study, we developed a conductive thread-based immunosensor (CT-IS), a biosensor to easily detect the presence of airborne viruses. CT-IS utilizes an antibody that specifically recognizes the HA protein of the pandemic influenza A (pH1N1) virus, which is incorporated into the conductive thread. The antigen-antibody interaction results in increased strain on the conductive thread in the presence of the pH1N1 virus, resulting in increased electrical resistance of the CT-IS. We evaluated the performance of this sensor using the HA protein and the pH1N1 virus, in addition to samples from patients infected with the pH1N1 virus. We observed a significant change in resistance in the pH1N1-infected patient samples (positive: n = 11, negative: n = 9), whereas negligible change was observed in the control samples (patients not infected with the pH1N1 virus; negative). Hence, the CT-IS is a lightweight fiber-type sensor that can be used as a wearable biosensor by combining it with textiles, to detect the pH1N1 virus in a person's vicinity.


Subject(s)
Biosensing Techniques , Influenza A Virus, H1N1 Subtype , Influenza, Human , Humans , Influenza, Human/diagnosis , Immunoassay , Antibodies
SELECTION OF CITATIONS
SEARCH DETAIL