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1.
Clinical Immunology ; Conference: 2023 Clinical Immunology Society Annual Meeting: Immune Deficiency and Dysregulation North American Conference. St. Louis United States. 250(Supplement) (no pagination), 2023.
Article in English | EMBASE | ID: covidwho-20243903

ABSTRACT

Background: High-titer neutralizing anti-cytokine autoantibodies have been shown to be involved in several acquired diseases, including pulmonary alveolar proteinosis, cryptococcal meningitis, and disseminated/extrapulmonary Nocardia infections (anti-GM-CSF autoantibodies), disseminated mycobacterial disease (anti-IFN-gamma autoantibodies), and some cases of severe COVID-19 infection (anti-type 1 interferons). Currently, patient blood samples are shipped via courier and require temperaturecontrolled conditions for transfer. This method is expensive and requires patients to have access to medical personnel to draw the blood. However, the well-established technique of collecting blood on a paper card as a dried blood spot (DBS) for diagnosis offers a point of care alternative which can be performed with a simple finger prick. This method is less invasive, cheaper, and allows for easy transport of patient samples. Method(s): 30 uL of whole blood from patients was blotted on filter paper and stored at 4C until use. The filter paper was hole punched and each punched spot was eluted with 150 uL of a 0.05% Tween PBS solution at room temperature overnight. The eluate was screened for anti-cytokine autoantibodies using a particle-based approach. Patient plasma was also screened in conjunction for comparison. Result(s): We confirmed the presence of autoantibodies in the DBS eluate from 4 previously diagnosed patients with anti-GM-CSF autoantibodies and 2 patients with anti-IFN-gamma autoantibodies. Functional studies showed the DBS eluate from a patient with anti-GM-CSF autoantibodies was able to block GM-CSF-induced STAT-5 phosphorylation in normal PBMC. As a proof of concept and to increase the number of patients evaluated, we also confirmed the presence of anti-cytokine autoantibodies using dried plasma eluate from 9 patients with known anti-GM-CSF autoantibodies and 9 patients with anti-IFN-gamma autoantibodies. Levels detected in DBS analyses were comparable to the levels found in plasma from the same patients not subjected to blotting and elution. Temperature studies showed that the autoantibodies were detected at similar levels when stored at 4C, 25C, and 40C for a week. Conclusion(s): The diagnosis of pathogenic anti-cytokine autoantibodies should be considered in the context of unusual or adult-onset infections, and screening for this diagnosis can be performed with dried blood spot testing.Copyright © 2023 Elsevier Inc.

2.
International Journal of Obstetric Anesthesia ; Conference: Obstetric Anaesthesia Annual Scientific Meeting 2023. Edinburgh United Kingdom. 54(Supplement 1) (no pagination), 2023.
Article in English | EMBASE | ID: covidwho-20237803

ABSTRACT

Introduction: Effective spinal anaesthesia for caesarean delivery (CD) is assumed to cause bilateral sympathetic blockade with increased feet skin temperature due to vasodilatation [1]. There has been no published study of peripheral skin temperature measurements during spinal anaesthesia for CD. Our study investigated foot skin temperature changes as spinal anaesthesia was established. Method(s): A single centre, prospective observational study with ethics committee approval (IRAS No. 263967). With informed consent, 60 healthy parturients, 37-42 weeks' gestation with singleton pregnancy scheduled for category 4 CD with spinal anaesthesia were recruited. Standard spinal anaesthesia used 0.5% hyperbaric bupivacaine and diamorphine with IV Phenylephrine and fluids. Skin temperature was measured on the dorsum of both feet with Covidien Mon-a-Therm© skin thermistor sensors prior to intrathecal injection and every minute after until completion of surgery. Theatre room temperature and ambient temperature under surgical drapes were recorded. Two controls were recruited. Result(s): All participants had successful spinal anaesthesia. The Figure shows mean (95% CI) skin temperature changes of both feet of participants during spinal anaesthesia and for controls. The maximum rate of skin temperature increase occurred 5-12 minutes after spinal injection with temperature change plateauing after 30 mins. The mean temperature range was 5.54degreeC (min = 29.7degreeC;max = 35.2degreeC). Discussion(s): This study characterises for the first time the peripheral temperature changes in the feet that occur with sympathetic block after spinal anaesthesia in parturients. Increased bilateral foot skin temperatures occur within 10 minutes of spinal injection. This may be useful for determining successful spinal anaesthesia for CD in addition to other assessments [2]. The insights may be useful for assessing epidural analgesia. The study was supported by an OAA research grant. Data collected by ROAR group.Copyright © 2023 Elsevier Ltd

3.
Thin Solid Films ; 774, 2023.
Article in English | Web of Science | ID: covidwho-20236292

ABSTRACT

Herein, refined LaxCa0.89-xSr0.11MnO3 (LCSMO, x = 0.65, 0.68, 0.71 and 0.74) films were prepared through the sol-gel spin-coating. The influence of La3+ content on the structural properties of LCSMO films was investigated by X-ray diffraction and Atomic force microscope, demonstrating that LCSMO films can grow well on SrTiO3 (00l) substrate. Besides, X-ray photoemission spectroscopy verified the double exchange (DE) effect was weakened with La3+ dopant. The La3+ doping and interconnected grains boundaries (GBs) led to the weakening DE effect and GBs scattering, respectively. Due to superior GBs connectivity, the resistivity of LCSMO films was less than 7.1 x 10(-4) Omega.cm at low temperature of 100 K. Importantly, it is an effective control method to keep the temperature (T-k) corresponding to temperature coefficient of resistivity (TCR) at room temperature with Sr2+ content as constant in LCSMO films. At x = 0.71, the peak TCR value was found to be 8.84%/K and corresponding T-k was 283.15 K. These results are beneficial for advanced application of uncooling infrared bolometer.

4.
J Biol Chem ; 299(7): 104886, 2023 Jun 02.
Article in English | MEDLINE | ID: covidwho-20230741

ABSTRACT

The effect of mutations of the catalytic dyad residues of SARS-CoV-2 main protease (MProWT) on the thermodynamics of binding of covalent inhibitors comprising nitrile [nirmatrelvir (NMV), NBH2], aldehyde (GC373), and ketone (BBH1) warheads to MPro is examined together with room temperature X-ray crystallography. When lacking the nucleophilic C145, NMV binding is ∼400-fold weaker corresponding to 3.5 kcal/mol and 13.3 °C decrease in free energy (ΔG) and thermal stability (Tm), respectively, relative to MProWT. The H41A mutation results in a 20-fold increase in the dissociation constant (Kd), and 1.7 kcal/mol and 1.4 °C decreases in ΔG and Tm, respectively. Increasing the pH from 7.2 to 8.2 enhances NMV binding to MProH41A, whereas no significant change is observed in binding to MProWT. Structures of the four inhibitor complexes with MPro1-304/C145A show that the active site geometries of the complexes are nearly identical to that of MProWT with the nucleophilic sulfur of C145 positioned to react with the nitrile or the carbonyl carbon. These results support a two-step mechanism for the formation of the covalent complex involving an initial non-covalent binding followed by a nucleophilic attack by the thiolate anion of C145 on the warhead carbon. Noncovalent inhibitor ensitrelvir (ESV) exhibits a binding affinity to MProWT that is similar to NMV but differs in its thermodynamic signature from NMV. The binding of ESV to MProC145A also results in a significant, but smaller, increase in Kd and decrease in ΔG and Tm, relative to NMV.

5.
Topics in Antiviral Medicine ; 31(2):148, 2023.
Article in English | EMBASE | ID: covidwho-2314215

ABSTRACT

Background: COVID-19 vaccines that expand immunity against emerging variants of concern (VOC) are needed to protect against ongoing viral evolution. We investigated the impact of boosting nonhuman primates pre-immune to the original WA-1 strain with updated VOC vaccines on the breadth and magnitude of mucosal and systemic antibody (Ab) and T cell (Tc) responses. Method(s): Cynomolgus macaques were primed with 2 doses of WA-1 Spike protein encoded by either an IL-12 adjuvanted DNA vaccine administered by gene gun (GG) or a self-amplifying RNA vaccine (repRNA) delivered intramuscularly (IM) with a cationic nanocarrier (LIONTM/IM, HDT Bio) or by GG (FIG 1). A booster dose was administered at week 17 with DNA or repRNA vaccines expressing B.1.351 (Beta) and B.1.617 (Delta) Spike receptor-binding domains (RBDs) fused to influenza HA2 stem domain (SHARP, designed by AIR/ JP) followed by a final Beta + Delta + WA-1 SHARP boost at week 34. Blood and bronchoalveolar lavages (BAL) were collected before and after each dose. Binding and neutralizing Ab to VOCs, including Omicron strains, were measured by ELISA and pseudovirus neutralization assays. Tc responses to Spike protein (WA-1 peptides) were measured by ELISpot. Immune responses were compared between groups and between blood vs lung using non-parametric statistical tests. Result(s): Two doses of WA-1 DNA or repRNA vaccines induced broad Ab against all VOC with the repRNA vaccine inducing the highest titers. Boosting with VOC SHARP significantly increased mucosal and systemic Ab responses against all VOCs tested including Omicron. After final boost, all groups had comparable binding and neutralization Ab titers and Tc responses regardless of method of delivery (GG or LIONTM/IM) or formulation (DNA or repRNA). Tc responses were significantly higher in the BAL vs PBMC after WA-1 Spike doses (p=0.0420) and VOC SHARP boosters (p=0.0009). Conclusion(s): The WA-1 strain primed for broad responses against VOCs that were significantly boosted with updated SHARP vaccines including responses against Omicron, even though this strain was not included in any dose. This suggests that sequential immunization with updated vaccines may broaden mucosal and systemic immunity against future VOCs. The repRNA vaccine initially induced the strongest responses, but there were no differences between RNA and DNA following additional booster doses, a result that supports development of a more cost-effective, room temperature stable DNA vaccine for worldwide boosters. (Figure Presented).

6.
Sustainability ; 15(7):5831, 2023.
Article in English | ProQuest Central | ID: covidwho-2298834

ABSTRACT

As a riveting example of social housing in Brazil, the Minha Casa Minha Vida program was set in 2009 to diminish the 6-million-home housing deficit by offering affordable dwellings for low-income families. However, recurrent thermal discomfort complaints occur among dwellers, especially in the Baltimore Residential sample in Uberlândia City. To avoid negative effects of energy poverty, such as family budget constraints from the purchase of electric appliances and extra costs from power consumption, a simulation based on system dynamics modeling shows a natural ventilation strategy with a mixed combination of sustainable and energy-efficient materials (tilting window with up to 100% opening, green tempered glass, and expanded polystyrene wall) to observe the internal room temperature variation over time. With a 50% window opening ratio combined with a 3 mm regular glass window and a 12.5 cm rectangular 8-hole brick wall, this scenario presents the highest internal room temperature value held during the entire period. From the worst to the best-case scenario, a substantial reduction in the peak temperature was observed from window size variation, demonstrating that natural ventilation and constructive elements of low complexity and wide availability in the market contribute to the thermal comfort of residential rooms.

7.
Journal of Liquid Chromatography & Related Technologies ; 45(13-16):191-203, 2022.
Article in English | ProQuest Central | ID: covidwho-2296266

ABSTRACT

More than 2.9 million people have died as a result of the global demographic impact of the coronavirus illness of 2019 (COVID-19). Numerous antiviral and anti-inflammatory medications have FDA approval to treat COVID-19 patients. For the simultaneous determination of COVID-19 utilized medications (Remdesivir, Moxifloxacin, Dexamethasone, Apixaban, and paracetamol) in their dosage forms, a sensitive technique has been developed and validated. The aforementioned medications were separated and quantified with the help of experimental design. The Box-Behnken design was used in the experiment to optimize the chromatographic method's analytical parameters. It employed RP-HPLC with a UV detector. An INERTSIL ODS-3 C18 column (5 µm, 250 × 4.6 mm) with mobile phase composed of acetonitrile: 30 mmoL potassium dihydrogen phosphate buffer (pH = 7.5) (50:50, v/v), at room temperature was employed to separate the aforementioned drugs. Paracetamol was linear over the concentration range (1–50 µg/mL), Moxifloxacin (5–70 µg/mL), Apixaban (5–70 µg/mL), Dexamethasone (1–100 µg/mL), and Remdesivir (5–100 µg/mL). According to ICH guidelines, the new approach underwent thorough validation. Between the proposed method's results and those from the reference or reported methods, there was no significant difference. The technique is simple to use in research of the cited medications in their dosage forms for quality control aspects.

8.
1st International Conference on Software Engineering and Information Technology, ICoSEIT 2022 ; : 79-84, 2022.
Article in English | Scopus | ID: covidwho-2277390

ABSTRACT

During the current COVID-19 pandemic, the large number of positive cases of infection has resulted in medical institutions lacking personnel to treat patients who continue to arrive. As a result of these problems, supervision and monitoring of room conditions is still lacking or even non-existent, so that the recovery process can be hampered or can facilitate the transmission of the virus to other people. It takes a device or tool that can monitor conditions and regulate the isolation room so that the temperature and humidity remain in the optimal zone so that recovery can be optimal and also reduce the risk of virus transmission. Based on this description, the author applies the concept of IoT by utilizing the IoT platform system and designing a system and tool that can monitor and regulate the COVID-19 isolation room and convey this information quickly and concisely. In addition, this study also examines how well and easily understood the system is when used by end-users by using the System Usability Scale or SUS as its usability testing method. The results obtained from this study are that the system and equipment function properly, the automation system and the method used are able to mitigate changes in temperature and humidity in the isolation room, and through the SUS method, the level of usability for end-users is deemed quite sufficient. © 2022 IEEE.

9.
Nanocomposites ; 8(1):13-23, 2022.
Article in English | ProQuest Central | ID: covidwho-2271668

ABSTRACT

Membrane materials might be used for face protection because they can decontaminate the inhaled air from particle pollution and viruses like the SARS-Cov0-2 which damages our respiration system. In this study, plyethersulfone membranes (PES) were synthesized with green solvent at room temperature and its filtration effectiveness was investigated against nano-bacteria (size 0.05 to 0.2 µm) by measuring their Bacterial Filtration Efficiency (BFE) and micro aerosol size (0.3 µm), and Particulate Filtration Efficiency (PFE). The average SARS-CoV-2 diameters are between 50 nm to 160 nm. A series of experiments were performed to accomplish between 0.03 to 0.21 µm PES sponge like diameters so that can be used for SARS-CoV-2 filtration. Results showed that nanofiltration/ultrafiltration could filter 99.9% of bacteria and aerosol from contaminated air the size of the Covid-19 molecule.

10.
Microbiology Research ; 12(2):395-402, 2021.
Article in English | EMBASE | ID: covidwho-2269854

ABSTRACT

Not only since SARS-CoV-2, have transmission routes of viruses been of interest. Noroviruses e.g., can be transmitted via smear infection, are relatively stable in the environment and very resistant to chemical disinfection. Some studies determined the virucidal efficacy of laundering processes, but few studies focused on the virucidal efficacy of dishwashing processes. Here, especially consumer related conditions are of interest. Households for example are a hotspot of norovirus infection and thus a sufficient reduction of these and other viruses from dishes must be insured to avoid an infection via this route. The likelihood of such an event should not be underestimated, since it was shown that the washing machine can be a reservoir for the transmission of extended spectrum beta-lactamase producing bacteria in newborns. Although viruses do not replicate in these devices a transmission via contaminated cutlery e.g., cannot be excluded. Using a consumer related approach to determine the virucidal efficacy of dishwashers, we found a combination of a bleach containing dishwasher detergent, a cleaning temperature of 45 C for 45 min and a rinsing temperature of 50 C, to be sufficient to reduces viral titer of bovine corona virus, murine norovirus and modified vaccinia virus by 4.8, 4.2 and 3.8 logarithmic stages respectively.Copyright © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

11.
Antibiotiki i Khimioterapiya ; 67(9-10):35-41, 2022.
Article in Russian | EMBASE | ID: covidwho-2265649

ABSTRACT

Interferons (IFN) have antiviral activity against many viruses, including SARS-CoV-2. A combination of IFN-a2b and the antioxidant taurine is widely used in the Russian Federation, and its antiviral activity has not been studied before. The aim of this study was to determine the antiviral activity of interferon drugs, in combination with taurine and without it. The study included cytotoxicity and antiviral activity assays of IFN-a2b preparations, when stored according to the instructions at 2-8degreeC, and after 1 month storage at the temperature of 20-26degreeC in a pre-opened state. The combination of IFN alpha-2b with taurine has a higher antiviral activity compared to IFN alpha-2b mono-preparation by more than 25% at a <<low>> and 85% at a <<high>> multiplicity of infection. Selectivity index for combinations of IFN-a2b (50,000 IU/dose) + taurine (1 mg/ml) and IFN-a2b (10,000 IU/ml) + taurine (0.8 mg/ml) was more than 600 units, whereas for the IFN-a2b (10,000 IU/ml) it was 200 units. Antiviral activity does not change after one month at room temperature. The combination of interferon with taurine at high concentrations was less toxic than interferon. The results obtained demonstrate practicability of interferon alpha-2b and taurine combination use for treatment and prevention of COVID-19.Copyright © Team of Authors, 2022.

12.
Anaesthesia, Pain and Intensive Care ; 27(1):135-138, 2023.
Article in English | EMBASE | ID: covidwho-2284684

ABSTRACT

Toxic epidermal necrolysis (TEN), is an acute, life-threatening emergent disease involving the skin and mucous membranes with serious systemic complications. It is characterized by widespread epidermal sloughing. Drugs are the most common triggers of TEN, but infection, vaccination, radiation therapy and malignant neoplasms can all induce it in susceptible patients. We report two cases in whom a hair dye and a COVID-19 vaccine (BioNTech, Pfizer) were believed to be the causative agents. These patients have to undergo repeated debridements of the necrotic tissue. In this manuscript the anesthetic management of TEN patients is discussed. Detailed preoperative evaluation, aggressive fluid and electrolyte replacement, avoidance of hypothermia during debridement, minimizing anesthetic agents and limiting traumatic procedures are key points in the management.Copyright © 2023 Faculty of Anaesthesia, Pain and Intensive Care, AFMS. All rights reserved.

13.
1st IEEE International Interdisciplinary Humanitarian Conference for Sustainability, IIHC 2022 ; : 1392-1396, 2022.
Article in English | Scopus | ID: covidwho-2283412

ABSTRACT

Now a days, the merciless covid-19 is threatening the world in everywhere. And, people are instructed to protect themselves from the virus infections. So, our proposed work will monitor the area around the person with the help of multiprocessor. In this method, particular area's temperature will be monitored by the advanced multiprocessor and the moisture level of the room around the person checked/ verified. And, spraying sanitizer will sanitize automatically, if it is necessary. Moreover, this system reduces the man power and protects the environment from the affects of covid-19. With the use of MSP, we can monitor the temperature and clean up mechanism will run automatically. From this method, we will permit the secured and sanitized people into the crowd places such as stock market, shops and stations. The vital recognition of this method is that fully automated procedure. Hence, it will replace physical labor and save time and also control the virus from spreading one to one another. © 2022 IEEE.

14.
Antibiotiki i Khimioterapiya ; 67(45208):35-41, 2022.
Article in Russian | EMBASE | ID: covidwho-2242020

ABSTRACT

Interferons (IFN) have antiviral activity against many viruses, including SARS-CoV-2. A combination of IFN-a2b and the antioxidant taurine is widely used in the Russian Federation, and its antiviral activity has not been studied before. The aim of this study was to determine the antiviral activity of interferon drugs, in combination with taurine and without it. The study included cytotoxicity and antiviral activity assays of IFN-a2b preparations, when stored according to the instructions at 2-8°C, and after 1 month storage at the temperature of 20-26°C in a pre-opened state. The combination of IFN alpha-2b with taurine has a higher antiviral activity compared to IFN alpha-2b mono-preparation by more than 25% at a «low» and 85% at a «high» multiplicity of infection. Selectivity index for combinations of IFN-a2b (50,000 IU/dose) + taurine (1 mg/ml) and IFN-a2b (10,000 IU/ml) + taurine (0.8 mg/ml) was more than 600 units, whereas for the IFN-a2b (10,000 IU/ml) it was 200 units. Antiviral activity does not change after one month at room temperature. The combination of interferon with taurine at high concentrations was less toxic than interferon. The results obtained demonstrate practicability of interferon alpha-2b and taurine combination use for treatment and prevention of COVID-19.

15.
Pharmacy Education ; 20(3):142.0, 2020.
Article in English | EMBASE | ID: covidwho-2237693

ABSTRACT

Background: COVID-19 is the current most prominent global health problem. Rapid and accurate diagnosis of disease is one of the most important factors in eliminating the spread of the virus;developing countries are currently facing many problems related to the high cost of PCR tests for COVID-19. Purpose(s): To develop a fast, accurate and low-cost method for making a PCR test for COVID-19. Method(s): The method was based on the use of the RPA (Recombinase Polymerase Amplification) method. By making a microfluidic device including restored (RPA) Mixture and immobilised probes designed for the RPA reaction to take place inside. The experiments were conducted on 20 clinical samples, and conducted at the Faculty of Pharmacy, Tanta University. Result(s): The results were identical in approximately 90% of the samples used and results were available after 30 minutes at normal room temperature. The results were read by measuring the level of the precipitate of the RPA reaction products resulting from the interaction of the reaction mixture with the Viral RNA. Conclusion(s): This method is considered one of the fastest ways to detect COVID19 infection and it is the least expensive and can be used in developing countries and as point-of-care testing.

16.
Business Systems Research ; 13(3):130-143, 2022.
Article in English | ProQuest Central | ID: covidwho-2198297

ABSTRACT

Background: E-commerce has emerged as a good response to the pandemic of COVID-19. However, the costs of providing a service, which includes a driver and a vehicle, in a regular vehicle that can transport goods that need positive cold (0° to 5°C) are very high.Objectives: This paper aims to investigate how a big Portuguese retailer company can reduce its dependence on refrigerated vehicles, simplifying operations and reducing the costs of transporting positive and negative cold food.Methods/Approach: This research was carried out in a food retailer Portuguese company, more precisely in a Dark Store dedicated to the online channel. The study was developed based on the AS-IS/TO-BE process analysis methodology, starting with the analysis of the current situation, giving rise to the so-called AS-IS model.Results: It was possible to reduce costs associated with transporting positive cold goods. As a result, there are 30% fewer costs associated with order transportation. With an additional 10% in space optimization with the gain of space within the galley of each vehicle.Conclusions: The costs of transporting positive and negative cold foods were decreased, and substituting vehicles with room temperature transport reduced the need for refrigerated vehicles.

17.
International Journal of Innovation and Applied Studies ; 38(2):262-270, 2022.
Article in English | ProQuest Central | ID: covidwho-2147521

ABSTRACT

The cereal group occupies a prominent place in the dietary habits of the populations of southern Benin and there are few recent consumption data on cereals. This study aims to assess the consumption, acquisition and supply of cereals to households in Cotonou. A semi-directive survey with KoB°Collect was conducted with 345 households to collect individual cereal food consumption data. The survey data studied by inferential statistics showed that the most consumed cereals are corn (99%, p=l), rice (85%, p=0.936), wheat (35%, p=0.999), sorghum (15%, p=0.659), millet (10%, p=0.971) and fonio at less than 5%. The most common mode of acquisition is buying from secondary market (95%, p=0.987) and street (85%, p=0.999) retailers. The most used preservation techniques are: drying at room temperature (70%, p=0.619) and keeping the product away from light (30%, p=0.806). Households most often dry in areas laid out at home (70%, p=0.984) or at the edge of the road (30%, p=0.939). Storage places are very diverse: the kitchen (45%, p=0.871), the bedroom (40%, 0.998), the living room (25%, p=0.900) and the store (20, 0.931). In addition, the supply costs of cereals increased from 0.009 USD to 0.056 USD between 2020 and 2021. This vertiginous rise in prices is due to the covid19 pandemic. The various data emitted make it possible not only to have fresh data but also to invest them in the assessment of health risks for the achievement of a high level of protection of the health and life of consumers.

18.
J Mol Biol ; 434(24): 167876, 2022 Dec 30.
Article in English | MEDLINE | ID: covidwho-2131576

ABSTRACT

We recently demonstrated that inhibitor binding reorganizes the oxyanion loop of a monomeric catalytic domain of SARS CoV-2 main protease (MPro) from an unwound (E) to a wound (active, E*) conformation, independent of dimerization. Here we assess the effect of the flanking N-terminal residues, to imitate the MPro precursor prior to its autoprocessing, on conformational equilibria rendering stability and inhibitor binding. Thermal denaturation (Tm) of C145A mutant, unlike H41A, increases by 6.8 °C, relative to wild-type mature dimer. An inactivating H41A mutation to maintain a miniprecursor containing TSAVL[Q or E] of the flanking nsp4 sequence in an intact form [(-6)MProH41A and (-6*)MProH41A, respectively], and its corresponding mature MProH41A were systematically examined. While the H41A mutation exerts negligible effect on Tm and dimer dissociation constant (Kdimer) of MProH41A, relative to the wild type MPro, both miniprecursors show a 4-5 °C decrease in Tm and > 85-fold increase in Kdimer as compared to MProH41A. The Kd for the binding of the covalent inhibitor GC373 to (-6*)MProH41A increases ∼12-fold, relative to MProH41A, concomitant with its dimerization. While the inhibitor-free dimer exhibits a state in transit from E to E* with a conformational asymmetry of the protomers' oxyanion loops and helical domains, inhibitor binding restores the asymmetry to mature-like oxyanion loop conformations (E*) but not of the helical domains. Disorder of the terminal residues 1-2 and 302-306 observed in both structures suggest that N-terminal autoprocessing is tightly coupled to the E-E* equilibrium and stable dimer formation.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Catalytic Domain , SARS-CoV-2/genetics , Crystallography, X-Ray , Peptide Hydrolases/chemistry
19.
Mater Today Bio ; 18: 100507, 2023 Feb.
Article in English | MEDLINE | ID: covidwho-2131928

ABSTRACT

Antibiotic resistance is a global public health threat, and urgent actions should be undertaken for developing alternative antimicrobial strategies and approaches. Notably, bismuth drugs exhibit potent antimicrobial effects on various pathogens and promising efficacy in tackling SARS-CoV-2 and related infections. As such, bismuth-based materials could precisely combat pathogenic bacteria and effectively treat the resultant infections and inflammatory diseases through a controlled release of Bi ions for targeted drug delivery. Currently, it is a great challenge to rapidly and massively manufacture bismuth-based particles, and yet there are no reports on effectively constructing such porous antimicrobial-loaded particles. Herein, we have developed two rapid approaches (i.e., ultrasound-assisted and agitation-free methods) to synthesizing bismuth-based materials with ellipsoid- (Ellipsoids) and rod-like (Rods) morphologies respectively, and fully characterized physicochemical properties. Rods with a porous structure were confirmed as bismuth metal-organic frameworks (Bi-MOF) and aligned with the crystalline structure of CAU-17. Importantly, the formation of Rods was a 'two-step' crystallization process of growing almond-flake-like units followed by stacking into the rod-like structure. The size of Bi-MOF was precisely controlled from micro-to nano-scales by varying concentrations of metal ions and their ratio to the ligand. Moreover, both Ellipsoids and Rods showed excellent biocompatibility with human gingival fibroblasts and potent antimicrobial effects on the Gram-negative oral pathogens including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum. Both Ellipsoids and Rods at 50 â€‹µg/mL could disrupt the bacterial membranes, and particularly eliminate P. gingivalis biofilms. This study demonstrates highly efficient and facile approaches to synthesizing bismuth-based particles. Our work could enrich the administration modalities of metallic drugs for promising antibiotic-free healthcare.

20.
Ann Transl Med ; 10(19): 1064, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2091301

ABSTRACT

Background: The global coronavirus disease 2019 (COVID-19) pandemic has caused immeasurable losses to society. An important part of disease prevention and control is to diagnose infected patients as soon as possible, and nucleic acid detection plays an important role in diagnosing diseases such as COVID-19. Reverse transcription-polymerase chain reaction (RT-PCR) is a common method for the diagnosis of COVID-19 infection, but the false negative rate of covid nucleic acid is currently very high. Methods: In this paper, HEK293T cells and lentivirus were used to verify the effect of virus preservation solution, fluorescence method was used to verify the inactivation effect of virus preservation solution, real-time fluorescence PCR experiment was used to verify that the genetic material in virus particles was not destroyed, and protein gel electrophoresis was used to verify the integrity of virus particles in the preservation solution. Results: In this study, we developed a new virus preservation solution using homogeneous reaction technology that can immediately inactivate the virus within 5 minutes at room temperature and maintain the stability of viral nucleic acid for at least 7 days. Importantly, we found that while our solution differed from existing commercial preservatives that contain guanidinium, analyzing the cycle threshold (Ct) showed that it still maintained virion integrity. Conclusions: These advantages could reduce false negatives and the risk of laboratory exposure to infection. In addition, our solution achieved room temperature preservation, which could aid in the transportation of samples. Therefore, this new sample preservation solution could provide significant benefits to the clinical detection of viruses such as COVID-19.

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