Preparation of biguanidine quaternary ammonium salts grafted chitosan with enhanced antibacterial and antibiofilm activities.

N-(4-N'-pyridine-benzylcarbonyl chloride) chitosan (CBPyC), N-p-biguanidine benzoyl chitosan (CSBG), and N-(p-biguanidine -1-pyridine-4-benzylcarbonyl chloride) chitosan (CSQPG) were synthesized. The structures of prepared chitosan derivatives were characterized using nuclear magnetic resonance spectroscopy (NMR) and ultraviolet-visible (UV-vis) spectroscopy, and the degree of substitution was determined through elemental analysis (EA) and evaluated on the basis of the integral values in 1H NMR. The antibacterial activities of chitosan derivatives against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated in vitro using antibacterial rate, minimal inhibitory concentration and minimum bacterial concentration assays. The antibiofilm activity was also assessed using the crystal violet assay. CSQPC exhibited higher antibacterial and antibiofilm activities against E. coli and S. aureus compared to CBPyC and CSBG. The antibacterial rate of CSQPG against E. coli and S. aureus at a concentration of 0.5 mg/mL was 43.3% and 100%, respectively. The biofilm inhibition rate of CSQPG at 0.5 MIC against E. coli and S. aureus was 56.5% and 69.1%, respectively. At a concentration of 2.5 mg/mL, the biofilm removal rates of E. coli and S. aureus were 72.9% and 90.1%, respectively. The antibacterial and antibiofilm activities of CSQPG were better than CSBG and CBPyC, and the combination of guanidine and quaternary ammonium further improved the positive charge density of chitosan and enhanced its antibacterial activity.

Clinical evidence for silver diamine fluoride to reduce dentine hypersensitivity: A systematic review.

OBJECTIVE: To assess the clinical evidence for silver diamine fluoride (SDF) to reduce dentine hypersensitivity in adults. METHODS: Two independent researchers searched the English literature in five databases (Scopus, PubMed, Web of Science, EMBASE and the Cochrane Library) up to 15th July 2023 for clinical trials investigating the desensitising effect of professionally applied SDF to manage dentine hypersensitivity in adults aged 18 or above at any follow-up period. The primary outcome was the change in dentine hypersensitivity between baseline and follow-up visits after SDF application regarding any validated pain outcome measures. The Cochrane guidelines were used for the risk of bias assessment. RESULTS: Three hundred and thirty-one studies were identified, and four of them were finally included. Three of the included studies were rated as having a 'low risk' of bias. The SDF solution reduced dentine hypersensitivity in adults. The percentage reduction in dentine hypersensitivity ranged from 23 % to 56 % after a single application of SDF solution. Moreover, the SDF solution was more effective than potassium nitrate, potassium oxalate and glutaraldehyde plus hydroxyethyl methacrylate in reducing dentine hypersensitivity. Meta-analysis indicated a more significant reduction in visual analogue scales (1-10) by 1.35 (95 % CI:0.9-1.8; p<0.00001) after receiving the SDF application than controls. CONCLUSION: The included clinical trials showed that SDF solution reduced dentine hypersensitivity in adults. However, clinical trials are few, and their protocol varied from one another. Further well-designed clinical trials should be conducted to provide more evidence on its use to manage dentine hypersensitivity. CLINICAL SIGNIFICANCE: SDF is cleared as desensitizing agents by the US Food and Drug Administration to manage dentine hypersensitivity, which induces pain, limits food choice, and impacts the quality of life. Evidence from this systematic review informs clinicians and provides researchers insight for future research on SDF use for dentine hypersensitivity. THE INTERNATIONAL PROSPECTIVE REGISTER OF SYSTEMATIC REVIEWS (PROSPERO) REGISTRATION NUMBER: CRD42023462613.

Protocol for aqueous synthesis of bioactive quaternary ammonium betaine derivatives under blue LED.

Quaternary ammonium compounds exhibit diverse applications as antibiotics, as surfactants, in paper industries, in sewage treatment, and in aquaculture. Here, we present a protocol for synthesizing a library of bioactive quaternary ammonium betaine derivatives under blue LED in water. We describe steps for preparing diazo compounds, synthesizing glycine betaine derivatives, and isolating pure final compounds via precipitation from an aqueous reaction mixture. This protocol promotes a sustainable approach by using water as the reaction medium and room temperature reactions. For complete details on the use and execution of this protocol, please refer to Rath et al. (2023).1.

Polypropylene-Rendered Antiviral by Three-Dimensionally Surface-Grafted Poly(N-benzyl-4-vinylpyridinium bromide).

To inhibit viral infection, it is necessary for the surface of polypropylene (PP), a polymer of significant industrial relevance, to possess biocidal properties. However, due to its low surface energy, PP weakly interacts with other organic molecules. The biocidal effects of quaternary ammonium compounds (QACs) have inspired the development of nonwoven PP fibers with surface-bound quaternary ammonium (QA). Despite this advancement, there is limited knowledge regarding the durability of these coatings against scratching and abrasion. It is hypothesized that the durability could be improved if the thickness of the coating layer were controlled and increased. We herein functionalized PP with three-dimensionally surface-grafted poly(N-benzyl-4-vinylpyridinium bromide) (PBVP) by a simple and rapid method involving graft polymerization and benzylation and examined the influence of different factors on the antiviral effect of the resulting plastic by using a plaque assay. The thickness of the PBVP coating, surface roughness, and amount of QACs, which jointly determine biocidal activity, could be controlled by adjusting the duration and intensity of the ultraviolet irradiation used for grafting. The best-performing sample reduced the viral infection titer of an enveloped model virus (bacteriophage ϕ6) by approximately 5 orders of magnitude after 60 min of contact and retained its antiviral activity after surface polishing-simulated scratching and abrasion, which indicated the localization of QACs across the coating interior. Our method may expand the scope of application to resin plates as well as fibers of PP. Given that the developed approach is not limited to PP and may be applied to other low-surface-energy olefinic polymers such as polyethylene and polybutene, our work paves the way for the fabrication of a wide range of biocidal surfaces for use in diverse environments, helping to prevent viral infection.

Effect of silver diamine fluoride and nano silver fluoride on oral health-related quality of life of children with early childhood caries: A randomized clinical trial.

OBJECTIVES: Untreated caries in primary teeth is one of the most prevalent health problems in children worldwide. Silver diamine fluoride (SDF) non-invasively arrests caries but causes staining unlike Nano Silver Fluoride (NSF) which causes no stains. This study compared the effect of NSF and 38 % SDF on the oral health related quality of life (OHRQoL) of preschool children after 6 months. METHODS: Children were included if they were younger than 4 years, with at least one active lesion, ICDAS score ≥3, attending nurseries in a rural area in Alexandria, Egypt. They were randomly assigned to receive NSF once at baseline, or SDF at baseline and after 6 months. The Arabic version of the Early Childhood Oral Health Impact Scale (A-ECOHIS) was used to assess the OHRQoL. The groups were compared using chi-square test and the effect of the intervention on OHRQoL was assessed using multiple linear regression. RESULTS: 360 children were included, mean (SD) age = 42.3 (8.2) months. After 6 months, NSF had significantly lower A-ECOHIS scores than SDF in bivariate analysis (p< 0.05) and in regression analysis (B= -5.02, p = 0.001) after adjusting for confounders. There were significant reductions in the A-ECOHIS total and domains' scores in both study groups, except for the social interaction domain in the SDF group. CONCLUSION: After 6-month, both agents significantly improved children's OHRQoL although NSF had a significantly better impact on OHRQoL than SDF. CLINICAL SIGNIFICANCE: Patient-reported outcomes support the inclusion of the two agents among the options for ECC management with better effect on quality of life after NSF. TRIAL REGISTRATION: The trial was registered in the clinicaltrials.gov registry (#NCT05255913).

Quaternary ammonium salts for water treatment with balanced rate of sterilization and degradation.

The growing number of infections caused by drug-resistant bacteria which arise from the overuse of antibiotics has severely affected the normal operation of human society. The high antibacterial activity of QAS makes it promising as an alternative to antibiotics, but it suffers from secondary pollution due to its non-degradation. Here we have synthesized a class of gemini quaternary ammonium salts (GQAS) with different carbon chain lengths containing ester groups by using facile methylation reaction. Quaternary ammonium groups contribute to insert negatively charged bacterial membranes, resulting in membrane damage and bacteria death. Compared with conventional single-chain QAS, except for the more efficient antibacterial efficiency attribute to the presence of the second carbon chain, GQAS with alterable antibacterial properties can minimize the possibility of bacterial resistance and reduce the accumulation of GQAS in the environment through the introduction of degradable ester groups. GQAS is completely superior to the commercial bactericide benzalkonium chloride (BAC) in both antibacterial activity and degrade performance, which can be used as a more environmentally friendly bactericide.

Resistance to Chlorhexidine and Benzalkonium Chloride in E. Coli ST131, A. Baumannii, and P. Aeruginosa Isolates.

BACKGROUND: The goal was to assess the antimicrobial efficacy of two commonly used biocides, chlorhexidine, and benzalkonium chloride, against MDR isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli ST131, as well as the prevalence of resistance genes. METHODS: MIC of chlorhexidine and benzalkonium chloride and their effects on both the planktonic phase and biofilm were determined. Finally, the presence of genes responsible for resistance to quaternary ammonium compounds was investigated by PCR. RESULTS: No significant relationship was observed between the presence of resistance genes and different concentrations of quaternary ammonium compounds (benzalkonium chloride). There was no association between biofilm formation and the presence of resistance genes. CONCLUSIONS: Chlorhexidine digluconate and benzalkonium chloride at appropriate concentrations could prevent biofilm formation.

Improvement of the Antioxidant and Antitumor Activities of Benzimidazole-Chitosan Quaternary Ammonium Salt on Drug Delivery Nanogels.

The present study focused on the design and preparation of acid-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for a controlled, slow-release of Doxorubicin HCl (DOX.HCl). The BIMIXHAC was crosslinked with sodium tripolyphosphate (TPP) using the ion crosslinking method. The method resulted in nanogels with low polydispersity index, small particle size, and positive zeta potential values, indicating the good stability of the nanogels. Compared to hydroxypropyl trimethyl ammonium chloride chitosan-Doxorubicin HCl-sodium tripolyphosphate (HACC-D-TPP) nanogel, the benzimidazole-chitosan quaternary ammonium salt-Doxorubicin HCl-sodium tripolyphosphate (BIMIXHAC-D-TPP) nanogel show higher drug encapsulation efficiency and loading capacity (BIMIXHAC-D-TPP 93.17 ± 0.27% and 31.17 ± 0.09%), with acid-responsive release profiles and accelerated release in vitro. The hydroxypropyl trimethyl ammonium chloride chitosan-sodium tripolyphosphate (HACC-TPP), and benzimidazole-chitosan quaternary ammonium salt-sodium tripolyphosphate (BIMIXHAC-TPP) nanogels demonstrated favorable antioxidant capability. The assay of cell viability, measured by the MTT assay, revealed that nanogels led to a significant reduction in the cell viability of two cancer cells: the human lung adenocarcinoma epithelial cell line (A549) and the human breast cancer cell line (MCF-7). Furthermore, the BIMIXHAC-D-TPP nanogel was 2.96 times less toxic than DOX.HCl to the mouse fibroblast cell line (L929). It was indicated that the BIMIXHAC-based nanogel with enhanced antioxidant and antitumor activities and acidic-responsive release could serve as a potential nanocarrier.

A novel chitosan antioxidant bearing sulfhydryl group: Synthesis, characterization and activity assessment.

To improve the antioxidant activity, sulfhydryl groups (-SH) were introduced into chitosan. Acylated chitosan derivatives, chitosan cationic salt derivatives, hydroxypropyl trimethylammonium chloride chitosan quaternary ammonium salt (HACC) derivatives and N,N,N-trimethyl chitosan iodine (TMC) derivatives were obtained. The chitosan derivatives were characterized by FTIR and 1H NMR to confirm the successful synthesis. Ellman's reagent was used to determine that the compound contained free sulfhydryl groups. The water solubility and thermal stability of chitosan and derivatives were evaluated. The antioxidant activities of the derivatives were verified, including DPPH radical scavenging activity, superoxide anion radical scavenging activity and reducing power activity. The novel chitosan derivatives showed excellent antioxidant activities. Toxicity assay used L929 cells proved that the derivatives had no significant toxic. The results showed that the chitosan derivatives bearing sulfhydryl groups described in this paper has a certain antioxidant effect, which provides a practical approach for further study of chitosan.

Silver Diamine Fluoride Staining With Potassium Iodide: A Prospective Cohort Study.

BACKGROUND: Staining after silver diamine fluoride (SDF) treatment limits treatment acceptability but is also used as a clinical indicator of lesion stability. Potassium iodide (KI) has been postulated to modify SDF staining. Understanding the natural history and resultant shade of SDF/KI-treated lesions will inform clinical decision-making. This study describes the change in colour of carious lesions in primary teeth treated with SDF and KI. METHODS: One hundred carious lesions in primary teeth were treated with SDF + KI (Riva Star, SDI) and followed up over 6 months. Lesion shade was determined using standardised intraoral photography and broadly categorised into 4 shades: yellow, light brown, dark brown, and black. Lesions were digitally isolated, and colour was evaluated using CIELAB (L*: lightness, a*/b*: hue) and perceptible colour change (ΔE). RESULTS: One hundred valid observations were analysed on 129 lesions included in the study. Lesions were excluded if subsequently restored (n = 15), teeth exfoliated (n = 2), exhibited pulpal exposure (n = 1), or failed to attend at follow-up visits (n = 11). At baseline, the shade of carious lesions was yellow (n = 22), light brown (n = 19), dark brown (n = 29), or black (n = 30). The changes in shade between baseline and 6 months were clinically perceptible to the human eye, with the mean ΔE being 12.2 (SD = 6.9). Neither tooth type, lesion severity, nor baseline shade was statistically associated with the degree of perceptible change at 6 months. CONCLUSIONS: Carious lesions exhibited clinically significant changes in colour after application of SDF + KI, primarily attributed to differences in L* of lesions over the 6 months.

Bitter Taste Receptor Agonist Denatonium Inhibits Stemness Characteristics in Hematopoietic Stem/Progenitor Cells.

Bone marrow microenvironmental stimuli profoundly impact hematopoietic stem cell fate and biology. As G protein-coupled receptors, the bitter taste receptors (TAS2Rs) are key in transmitting extracellular stimuli into an intracellular response, within the oral cavity but also in extraoral tissues. Their expression in the bone marrow (BM)-derived cells suggests their involvement in sensing the BM microenvironmental fluctuation. In the present study, we demonstrated that umbilical cord blood (UCB)-derived CD34+ cells express fully functional TAS2Rs along with the signal transduction cascade components and their activation by the prototypical agonist, denatonium benzoate, significantly modulated genes involved in stemness maintenance and regulation of cell trafficking. The activation of these specific pathways was confirmed in functional in vitro experiments. Denatonium exposure exerted an antiproliferative effect on UCB-derived CD34+ cells, mainly affecting the most undifferentiated progenitor frequency. It also reduced their clonogenicity and repopulating potential in vitro. In addition, the TAS2R signaling activation impaired the UCB-derived CD34+ cell trafficking, mainly reducing the migration toward the chemoattractant agent CXCL12 and modulating the expression of the adhesion molecules CD62L, CD49d, and CD29. In conclusion, our results in UCB-derived CD34+ cells expand the observation of TAS2R expression in the setting of BM-resident cells and shed light on the role of TAS2Rs in the extrinsic regulation of hematopoietic stem cell functions.

The effect of silver nanoparticles in addition to sodium fluoride on remineralization of artificial root dentin caries.

BACKGROUND: Silver nanoparticle was developed to overcome the drawback of silver diamine fluoride. However, evidence is limited, especially in root caries. The aim of this study was to evaluate the remineralization effect of silver nanoparticles on root caries. MATERIALS AND METHODS: Fifty-five root human dentin slices size 5 × 5 mm2 from patients aged over 60 years old were immersed in demineralized solution to create artificial caries. Specimens were allocated into five groups according to the remineralizing agents: silver diamine fluoride (SDF), silver nanoparticles solution (AgNPs), silver nanoparticle solution followed by sodium fluoride varnish (AgNPs+NaF), sodium fluoride varnish (NaF), and tap water. After 8 days of pH-cycling challenge, the microhardness test, lesion depth evaluation, dentin surface morphology, and elemental analysis were performed. Data was analysed using F-test One-way ANOVA followed by Tukey's post hoc test and paired T-test. RESULTS: All test groups demonstrated a significantly higher microhardness value and lower lesion depth compared with the control group. AgNPs+NaF and NaF-treated groups showed lower efficacy than SDF. Crystal precipitation was presented in all groups composed of silver. CONCLUSION: Addition of fluoride varnish did not benefit for silver nanoparticles in preventing further demineralization. SDF provides the highest effectiveness in elderly root carious dentin.

Evaluation of in vitro SARS-CoV-2 inactivation by a new quaternary ammonium compound: Bromiphen bromide.

The pneumonia (COVID-19) outbreak caused by the novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which unpredictably exploded in late December of 2019 has stressed the importance of being able to control potential pathogens with the aim of limiting their spread. Although vaccines are well known as a powerful tool for ensuring public health and controlling the pandemic, disinfection and hygiene habits remain crucial to prevent infection from spreading and maintain the barrier, especially when the microorganism can persist and survive on textiles, surfaces, and medical devices. During the coronavirus disease pandemic, around half of the disinfectants authorized by the US Environmental Protection Agency contained quaternary ammonium compounds (QACs); their effectiveness had not been proven. Herein, the in vitro SARS-CoV-2 inactivation by p-bromodomiphen bromide, namely bromiphen (BRO), a new, potent, and fast-acting QAC is reported. This study demonstrates that BRO, with a dose as low as 0.02%, can completely inhibit SARS-CoV-2 replication in just 30 s. Its virucidal activity was 10- and 100-fold more robust compared to other commercially available QACs, namely domiphen bromide and benzalkonium chloride. The critical micellar concentration and the molecular lipophilicity potential surface area support the relevance of the lipophilic nature of these molecules for their activity.

Combining with domiphen bromide restores colistin efficacy against colistin-resistant Gram-negative bacteria in vitro and in vivo.

Today, colistin is considered a last-resort antibiotic for treating multidrug-resistant (MDR) Gram-negative bacteria (GNB). However, the increased and improper use of colistin has led to the emergence of colistin-resistant (Col-R) GNB. Thus, it is urgent to develop new drugs and therapies in response to the ongoing emergence of colistin resistance. In this study, we investigated the antibacterial and antibiofilm activities of the quaternary ammonium compound domiphen bromide (DB) in combination with colistin against clinical Col-R GNB both in vitro and in vivo. Checkerboard assay and time-kill analysis demonstrated significant synergistic antibacterial effects of the colistin/DB combination. The synergistic antibiofilm activity was confirmed through crystal violet staining and scanning electron microscopy (SEM). Furthermore, the colistin/DB combination exhibited increased survival rates in infected larvae and reduced bacterial loads in a mouse thigh infection model. The cytotoxicity measurement and hemolysis test showed that the combination did not adversely affect cell viability at synergistic concentrations. The alkaline phosphatase (ALP) leak test and propidium iodide (PI) staining analysis further revealed that the colistin/DB combination enhanced the therapeutic effect of colistin by altering bacterial membrane permeability. The ROS assays revealed that the combination induced the accumulation of bacterial ROS, leading to bacterial death. In conclusion, our study is the first to identify DB as a colistin potentiator, effectively restoring the sensitivity of bacteria to colistin. It provides a promising alternative approach for combating Col-R GNB infections.

Testing a Method for Evaluation of the Viability of Biofilm-Forming Bacteria after Exposure to Disinfectants.

A method for determining the viability of opportunistic pathogenic bacteria at the stage of biofilm formation after exposure to disinfectants with different active components was tested. The method is based on oxidation of tetrazolium salts by metabolically active cells with the formation of colored formazan derivatives and their quantitative spectrophotometry. The cell viability in the biofilm decreased after exposure to quaternary ammonium compounds and chlorine-containing disinfectants, but their effect was reversible. Dissemination of cells that had retained viability from the biofilm occurred after 24 h. The algorithm of testing, necessary controls, counting, and data interpretation are specified. The method can be recommended for use in laboratory diagnostics and clinical practice.

Evaluation of the Antitumor Activity of Quaternary Ammonium Surfactants.

Quaternary ammonium surfactants, due to their diverse chemical structure and their biological properties, can be used in medicine as DNA carriers, disinfectants, and antimicrobial and antitumor agents. In this study, using melanoma A375, colon adenocarcinoma HT-29 and normal human dermal fibroblast (NHDF) cells, we tested the hypothesis that the quaternary ammonium surfactants 2-dodecanoyloxyethyl)trimethylammonium bromide (DMM-11), 2-dodecanoyloxypropyl)trimethylammonium bromide (DMPM-11) and 2-pentadecanoyloxymethyl)trimethylammonium bromide (DMGM-14) act selectively against cancer cells. The results showed that these compounds led to the initiation of the apoptotic process of programmed cell death, as evidenced by the ratio of the relative expression of Bax protein to Bcl-2. The encapsulation of surfactants in liposomes allowed lower concentrations to be used. Moreover, encapsulation reduced their toxicity towards non-cancerous cells. The anticancer efficiency and apoptotic effect of the liposomal formulations with surfactants (DMM-11, DMPM-11 and DMGM-14) were higher than those of surfactant-free liposomes. Therefore, quaternary ammonium surfactant-loaded liposomes show significant potential as delivery vehicles for the treatment of melanoma and colon cancers. The use of nano-formulations offers the advantage of optimizing quaternary ammonium surfactant delivery for improved anticancer therapy.

Influence of the Salivary Acquired Pellicle on the Inhibition/Progression of In Vitro Carious Dentin Treated with Silver Diamine Fluoride.

Purpose: To evaluate, in vitro, whether the presence of the acquired pellicle (AP) interferes with the effect of 38 percent silver diamine fluoride (SDF) on the inhibition or progression of carious dentin. Methods: Carious dentin specimens were divided into groups: C-no treatment control; FV-fluoride varnish; AP-acquired pellicle formation; SDF only, and APSDF-SDF plus acquired pellicle formation. After AP formation (AP and APSDF groups), all groups were subjected to pH cycling. Dentin mineral gain or loss was quantified using surface microhardness (SM). Concentrations of fluoride calcium (CaF2) and fluorapatite (FAp) fluoride retained in dentin and fluoride concentrations in de- and remineralizing solutions were determined. Results: Groups AP, FV, SDF, and APSDF showed reduced demineralization compared with the C group, but the AP group showed greater surface loss than the fluoridated groups. Groups FV, SDF, and APSDF showed greater mineral recovery than C and AP groups (P<0.05), but no differences were observed between the FV, SDF, and APSDF groups (P>0.05). The retained CaF2 and FAp were greater in the groups treated with fluoride, but there was no difference between the SDF and APSDF groups. Conclusion: The presence of the acquired pellicle reduced the progression of carious dentin lesion but did not influence its remineralization when associated with silver diamine fluoride.

Application of 20% silver nanoclusters in polymethacrylic acid on simulated dentin caries; its penetration depth and effect on surface hardness.

The aims of this study were: To evaluate the surface hardness of simulated dentin caries lesions treated with either silver nanoclusters (AgNCls) synthesized in polymethacrylic acid (PMAA) or 38% silver diammine fluoride (SDF), as well as observe the penetration of the treatment solutions into the simulated caries lesions. Dentin blocks 4 mm thick obtained from caries-free third molars were sectioned and then simulated caries lesions on the occlusal dentin surfaces were created. Each specimen (n = 8) was divided into four sections: (A) treated with 20% AgNCls/PMAA; (B) treated with SDF 38% (FAgamin, Tedequim, Cordoba, Argentina); (C) sound tooth protected by nail-varnish during artificial caries generation (positive control); and (D) artificial caries lesion without surface treatment (negative control). AgNCls/PMAA or SDF were applied on the simulated lesions with a microbrush for 10 s, then excess removed. The surface hardness was measured by means of Vickers indentation test. To trace the depth of penetration, up to 400 µm, of silver ions, elemental composition of the samples was observed using EDX, coupled with SEM, and measured every 50 µm from the surface towards the pulp chamber. Laser Induced Breakdown Spectroscopy (LIBS) was also employed to trace silver ion penetration; the atomic silver line 328.06 nm was used with a 60 µm laser spot size to a depth of 240 µm. Student's-t test identified significant differences between treatment groups for each depth and the Bonferroni test was used for statistical analysis of all groups (p < 0.05). Mean surface hardness values obtained were 111.2 MPa, 72.3 MPa, 103.3 MPa and 50.5 MPa for groups A, B, C and D respectively. There was a significant difference between groups A and C compared with groups B and D, the group treated with AgNCls/PMAA achieved the highest surface hardness, similar or higher than the sound dentin control. A constant presence of silver was observed throughout the depth of the sample for group A, while group B showed a peak concentration of silver at the surface with a significant drop beyond 50 µm. The 20% AgNCls/PMAA solution applied to simulated dentin caries lesions achieved the recovery of surface hardness equivalent to sound dentin with the penetration of silver ions throughout the depth of the lesion.

Catapol attenuates the aseptic inflammatory response to hepatic I/R injury in vivo and in vitro by inhibiting the HMGB1/TLR-4/NF-κB signaling pathway via the microRNA-410-3p.

BACKGROUND: Hepatic ischemia-reperfusion (I/R) injury involves inflammatory necrosis of liver cells as a significant pathological mechanism. Catapol possesses anti-inflammatory activity that is extracted from the traditional Chinese medicine, Rehmannia glutinosa. METHODS: The liver function and histopathology, Oxidative stress, and aseptic inflammatory responses were assessed in vivo, and the strongest dose group was selected. For mechanism, the expression of miR-410-3p, HMGB1, and TLR-4/NF-κB signaling pathways was detected. The dual luciferase assay can verify the targeting relationship between miR-410-3p and HMGB1. Knockdown of miR-410-3p in L02 cells is applied in interference experiments. RESULTS: CAT pre-treatment significantly decreased the liver function markers alanine and aspartate aminotransferases and reduced the areas of hemorrhage and necrosis induced by hepatic I/R injury. Additionally, it reduced the aseptic inflammatory response and oxidative stress, with the strongest protective effect observed in the high-dose CAT group. Mechanistically, CAT downregulates HMGB1, inhibits TLR-4/NF-κB signaling pathway activation, and reduces inflammatory cytokines TNF-α, and IL-1ß. In addition, the I/R-induced downregulation of microRNA-410-3p was inhibited by CAT pre-treatment in vivo and in vitro. HMGB1 was identified as a potential target of microRNA-410-3p using a dual-luciferase reporter assay. Knockdown of microRNA-410-3p abolished the inhibitory effect of CAT on HMGB1, p-NF-κB, and p-IκB-α protein expression. CONCLUSIONS: Our study showed that CAT pre-treatment has a protective effect against hepatic I/R injury in rats. Specifically, CAT attenuates the aseptic inflammatory response to hepatic I/R injury in vivo and in vitro by inhibiting the HMGB1/TLR-4/NF-κB signaling pathway via the microRNA-410-3p.

Determining the efficacy of disinfectants at nucleic acid degradation.

AIMS: Nucleic acids, particularly antibiotic resistance genes, are commonly found on surfaces within healthcare environments, with levels not reducing following cleaning. Within the UK, there are no regulations for testing disinfectants against nucleic acids. METHODS AND RESULTS: A series of commonplace in vitro methods were used to determine disinfectant-induced physical and functional damage to various nucleic acids; RNA (10 µg), genomic DNA (2 µg), and plasmids (1 µg). Using these methods, the optimal residence time (10 minutes) and working concentration (10%) were determined for a new disinfectant. Furthermore, comparison of disinfectants with different active ingredients including lactic acid (LA), sodium hydroxide (NaOH), chloroxylenol (PCMX), and quaternary ammonium compounds (QACs), were compared to controls. All disinfectants showed greater degradation by gel electrophoresis of genomic DNA and RNA than of purified plasmids. Functional analysis using quantitative polymerase chain reaction (qPCR) and polymerase chain reaction (PCR) demonstrated that no disinfectant tested (apart from control) could damage DNA to the level where PCR amplification was not possible, and only the NaOH reagent could achieve this for RNA. CONCLUSIONS: The set of methods described herein provides a platform for future standardization and potential regulation regarding monitoring cleaning solutions for their activity against nucleic acids.