Acid Challenge Research Articles

Scallop NEMO interacts with IKK1 and regulates host innate immunity against PAMPs

The IκB kinase (IKK) complex, which is essential for the activation of the transcription factor NF-κB, is composed of IKK1 (IKKα), IKK2 (IKKβ), and the key regulatory protein NF-κB essential modulator (NEMO). However, there are few studies on the function of NEMO in invertebrates. In this study, we obtained the complete coding sequence of the NEMO gene of the Zhikong scallop Chlamys farreri and studied its response to pathogen-related molecular pattern (PAMP) stimulation and its interaction with the IKK1 protein. Sequence analysis revealed that Chlamys farreri NEMO (CfNEMO) encodes 778 amino acids, and the encoded protein contains a typical NEMO domain, two coiled coils, a putative leucine zipper motif, and a C-terminal zinc finger domain. Phylogenetic relationship analysis showed that CfNEMO belongs to the NEMO family of mollusks in invertebrates. Real-time quantitative PCR showed that CfNEMO transcripts were expressed in all tissues tested in scallops, with the highest expression in the gills. Furthermore, the expression level of CfNEMO in the gills was significantly induced after lipopolysaccharide, peptidoglycan, and polyinosinic–polycytidylic acid challenge. Finally, the results of co-immunoprecipitation showed that CfNEMO can interact with IKK1 protein (IKKα/IKKβ family member). And by constructing truncated mutants, we found that the interaction between the two proteins is mediated by the NEMO domain of CfNEMO and the SDD (scaffold dimerization domain) domain of IKK1. In conclusion, our results lay the foundation for in-depth understanding of the innate immune function of invertebrate NEMO and the formation of the IKK complex. Our findings provide valuable information on disease control and management in scallop farming.

Caries inhibition of simulated active caries lesions with CO2 laser irradiation and fluoride.

It has been well established that CO2 laser irradiation can be used to transform the mineral phase of dental enamel to make it more resistant to acid dissolution. The purpose of this study was to investigate if carbon dioxide laser irradiation and topical fluoride can be used to treat incipient caries lesions to inhibit further progression, i.e. treat active lesion surfaces as opposed to sound surfaces prior to subjecting them to an acid challenge. Simulated active caries lesions were produced on twenty eight bovine enamel samples using a pH cycling model and those surfaces were irradiated by a 9.4 μm CO2 laser and treated with topical fluoride. Changes in the surface morphology, acid resistance, and permeability were measured using digital microscopy, optical coherence tomography (OCT), and SWIR reflectance surface dehydration rate measurements at 1950 nm after exposure to a further acid challenge. There was a significant reduction (P < 0.05) of further lesion progression for lesion windows treated with CO2 laser irradiation followed by the application of an acidulated phosphate fluoride gel compared to the untreated lesion windows on each sample. Treatment by laser irradiation alone was not effective. The degree of lesion inhibition was not as high as has been previously observed for laser irradiated sound enamel surfaces exposed to an acid challenge.

Restorative Materials Exposed to Acid Challenge: Influence of Temperature on In Vitro Weight Loss.

Consumption of acidic beverages and foods could provoke erosive damage, both for teeth and for restorative materials. Temperatures of consumption could influence the erosive effects of these products. The aim of this in vitro study is to assess the influence of an acidic challenge on the weight loss of different restorative materials. Resin composites and glass-ionomer cements (GIC) were tested. The medium of storage was Coca-Cola (Coca-Cola, Coca-Cola Company, Milano, Italy) at two different temperatures, 4 and 37 °C, respectively for Group A and Group B. For each group, nine specimens were prepared for each material tested. After 7 days, weight was assessed for each sample, and the percentage weight loss was calculated. For all the resin composites (Groups 1–13), no significant weight losses were noticed. (<1%). Conversely, GICs (Groups 14 and 15) showed significant weight loss during the acidic challenge, which was reduced in the case of these materials that included a protective layer applied above. Significant differences were registered with intra-group analysis; weight loss for specimens immersed in Coca Cola at 37 °C was significantly higher for almost all materials tested when compared to specimens exposed to a cooler medium. In conclusion, all the resin composites showed reliable behaviour when exposed to acidic erosion, whereas glass-ionomer cements generally tended to solubilize.

Role of diacylglycerol O-acyltransferase (DGAT) isoforms in bovine hepatic fatty acid metabolism

Fatty acid accumulation in hepatocytes induced by high concentrations of fatty acids due to lipolysis and the associated oxidative damage they cause occur most frequently after calving. Because of their role in esterification of fatty acids, diacylglycerol acyltransferase isoforms (DGAT1 and DGAT2) could play a role in the susceptibility of dairy cows to develop fatty liver. To gain mechanistic insights, we performed in vivo and in vitro analyses using liver biopsies or isolated primary hepatocytes. The in vivo study (n = 5 cows/group) involved healthy cows [average liver triacylglycerol (TAG) = 0.78%; 0.58 to 0.93%, ratio of triglyceride weight to wet liver weight] or cows diagnosed with fatty liver (average TAG = 7.60%; 5.31 to 10.54%). In vitro, hepatocytes isolated from 3 healthy female calves (1 d old, 44 to 53 kg) were challenged with (fatty acids) or without (control) a 1.2 mM mixture of fatty acids in an attempt to induce metabolic stress. Furthermore, hepatocytes were treated with DGAT1 inhibitor or DGAT2 inhibitor for 2 h followed by a challenge with (DGAT1 inhibitor + fatty acids or DGAT2 inhibitor + fatty acids) or without (DGAT1 inhibitor or DGAT2 inhibitor) the 1.2 mM mixture of fatty acids for 12 h. Data analysis of liver biopsies was compared using a 2-tailed unpaired Student's t-test. Data from calf hepatocyte treatment comparisons were assessed by one-way ANOVA, and multiplicity for each experiment was adjusted by the Holm's procedure. Data indicated that both fatty liver and in vitro challenge with fatty acids were associated with greater mRNA and protein abundance of SREBF1, FASN, DGAT1, and DGAT2. In contrast, mRNA and protein abundance of CPT1A and very low-density lipoprotein synthesis-related proteins MTTP and APOB were markedly lower. However, compared with fatty acid challenge alone, DGAT1 inhibitor + fatty acids led to greater mRNA and protein abundance of CPT1A and APOB, and greater mRNA abundance of SREBF1 and MTTP. Furthermore, this treatment led to lower mRNA abundance of FASN and DGAT2 and TAG concentrations. Compared with fatty acid challenge alone, DGAT2 inhibitor + fatty acids led to greater mRNA and protein abundance of CPT1A, MTTP, and APOB, and lower mRNA and protein abundance of SREBF1 and FASN. In addition, compared with control and fatty acids, there was greater protein abundance of GRP78 and PERK in both DGAT1 and DGAT2 inhibitor with or without fatty acids. Furthermore, compared with control and fatty acids, reactive oxygen species concentrations in the DGAT1 inhibitor with or without fatty acid group was greater. Overall, data suggested that DGAT1 is particularly relevant in the context of hepatocyte TAG synthesis from exogenous fatty acids. Disruption of both DGAT1 and DGAT2 altered lipid homeostasis, channeling fatty acids toward oxidation and generation of reactive oxygen species. Both DGAT isoforms play a role in promoting fatty acid storage into TAG and lipid droplets to protect hepatocytes from oxidative damage.

The Influence of Abrasive and Acidic Aggressions on the Surface Condition of Flowable Composite Resin.

The aim of this in vitro study was to evaluate the effect of hydrochloric acid associated with the abrasive effect of toothbrushing on the surface condition of three flowable composite resins used for direct restoration. Seventy samples of each composite resin: Grandio Flow (VOCO, Germany)—group A, Filtek Ultimate Flow (3M-ESPE, MN, USA)—group B, G-aenial Flo X (GC Europe)—group C were prepared, submersed in hydrochloric acid 30% for 60 min and then submitted to simulated toothbrushing procedure using 5000 cycles with toothbrushes with medium and hard bristles, immediately after the chemical attack, after 30 min or without any chemical attack. The sample’s surface roughness was analyzed using a noncontact profilometer (Dektak XT, Bruker, USA). ANOVA and post hoc Bonferroni tests, with a p < 0.05, were used to analyze the values. Hydrochloric acid action for 60 min and six months of toothbrushing using toothbrushes having medium hardness or firm bristles affects the surface roughness of tested flowable composite resins. Toothbrushing with firm bristles immediately after acidic challenge determines increased surface roughness for two of the three flowable composite resins (Grandio Flow and Filtek Ultimate Flow). Toothbrushing with medium or firm bristles thirty minutes after the acidic aggression determine no effect on surface condition of flowable composite resins.

The acid tolerance responses of the Salmonella strains isolated from beef processing plants

The development of the stationary-phase, low-pH-inducible acid tolerance response (ATR) in the Salmonella contaminant of beef during the processing arises food safety concerns, because it may evoke bacterial coping mechanisms against bactericidal insults and alter gene expression that contribute to pathogen virulence. However, information on the development of the ATR and the stability (defined as the capacity to maintain the acquired acid tolerance after induction) in the Salmonella during the production and distribution of beef is limited. After adaptation overnight, ATRs in the 79 strains of Salmonella isolated from beef processing plants were investigated by comparing the log reduction in the 2-h acid challenge trials at pH 3.0. Six representative strains were selected to further estimate the effect of three factors in the incubation period on the development of the ATR, including adapted pH values (5.0, 5.4, 6.0, and 7.0), temperatures (10 °C and 37 °C), and the adaptation media (meat extract and brain heart infusion media). The stability of acid tolerance during the long-time chilled storage (4 °C for 13 days) was also observed on two strains of serotypes S. Derby and S. Meleagridis. All the strains isolated from beef processing plants exhibited an enhanced acid tolerance indicating the widespread existence of ATR. The results also revealed that strain variability was present in the development of ATR. Significant tolerance to lethal acidic environments (pH 3.0) was found when the Salmonella strains had been acid-adapted in meat extract at pH 5.0, pH 5.4, or pH 6.0, which indicated the possible induction of ATR during beef production. After the acid adaptations, the population reduction after the acid challenge (BHI, pH = 3) in the strains was significantly lower than the non-induced at the 1d, 7 day and 13 day's storage in meat extract media at 4 °C, which revealed the persistence of ATR during beef distribution. Compared to 37 °C, adaptation in lower temperature (10 °C) significantly reduced the ATR and no ATR was developed when adapted in 4 °C. This emphasizes the importance of keeping a low temperature of beef throughout the supply chains of beef industry.

Role of phosphate-buffered saline on push-out bond strength of MTA Flow™ and Biodentine™ after acid challenge: An in vitro study.

Context:The physical and chemical properties of root repair materials are adversely affected when placed in areas of inflammation with acidic pH.Aim:To evaluate the role of phosphate-buffered saline (PBS– pH 7.4) on push-out bond strength (POBS) of MTA flow and Biodentine (BD) after acid challenge with butyric acid buffered solution (BABS– pH 5.4).Subjects and Methods:Eighty mid-root dentin slices (2 mm thick; 1.3 mm lumen diameter) were prepared and were divided into two groups (n = 40) based on the type of material used for filling lumen: Group 1-MTA Flow and Group 2-BD. Each group was again divided into four subgroups (n = 10) based on the duration of exposure to storage media: (a) 3 days in PBS, (b) 3 days in BABS, (c) 3 days in BABS followed by 30 days in PBS, and (d) 33 days in PBS. POBS was then measured using the universal strength testing machine.Statistical Analysis Used:Statistical analysis was performed with one-way analysis of variance and post hoc test using SPSS software version 23.0.Results:Group 1b and 2b showed significantly lower bond strength values. No significant difference was observed between Group 1b and Group 1c (P > 0.05), whereas highly significant POBS values were observed between Group 2b and Group 2c (P = 0.000). Among all the tested groups, Group 2d showed the highest POBS values.Conclusion:On storage in PBS after acid challenge, BD attained the highest POBS values while no significant difference was observed in MTA Flow.

Efeito do desafio ácido e distância de fotoativação na microdureza e rugosidade de resinas compostas bulk-fill flow

Abstract Introduction composite resins are indicated to the reconstruction of proximal walls and the evaluation of properties of flow bulk-fill composite resins exposed to acid challenge is necessary. Objective to evaluate the microhardness and roughness at different depths of photoactivation of bulk-fill flow composites (Filtek Bulk Fill Flow; SureFil SDR Flow; Tetric N Ceram Bulk fill) and conventional composite resin (control, Filtek Z350 XT) subjected to acid challenge. Material and method forty composites brick shaped specimens (3x3x4 mm) were made using a polyacetal matrix. To simulate pH challenges, the samples were immersed in a demineralizing solution. Each sample had Knoop microhardness (KHN) and roughness (Ra) evaluated at three depths (superficial, medium, and cervical), considering the lateral surface of the sample. Data were submitted to Kruskal-Wallis, Friedman's and Dunn's tests with a significance level of 5%. Result comparing the composites among themselves, in superficial (p=0.693), medium (p=0.053) and cervical (p=0.176) regions, there was no difference in the KHN values. There were also no differences in roughness between the composites in superficial (p=0.356), medium (p=0.734) and cervical (p=0.207) regions. Only the Filtek Z350 XT (p=0.027) showed less difference in KHN in the middle region caused by acid challenge. Changes in roughness showed that the greatest difference was at the cervical region for Bulk Fill Flow SDR (p=0.014) and Tetric N-Ceram Bulk Fill (p = 0.003) with an increase after acid challenge. Conclusion after acid challenge, bulk-fill flow composites showed alterations similar to those presented by the conventional nanoparticulate resin composite.

Effect of resin infiltration and bleaching on surface roughness and microhardness of human enamel with induced white spot lesions

Objective: To comparatively evaluate the effect of resin infiltration, bleaching and bleaching followed by resininfiltration on the surface roughness and microhardness of human enamel with induced white spot lesions(WSLs) and their resistance to acidic challenge. Material and Methods: Sixty human specimens were randomlydivided into three groups (n=20) according to the treatment modality applied; group I Icon® resin infiltration,group II bleaching and group III bleaching followed by Icon® resin infiltration. For each treatment modality, 10specimens were tested for surface roughness and another 10 for microhardness. WSLs were artificially inducedin all specimens and after treatment, all specimens were subjected to acidic challenge. Surface roughness wasmeasured by the tapping mode of the atomic force microscope (AFM) and microhardness was measured bydigital Vickers hardness tester at baseline, after induction of WSLs, after treatment and after acidic challenge.Results: Groups I and III showed significant reduction in surface roughness after treatment, while group II showedsignificant increase. Groups I and III showed significant increase in the microhardness after treatment, whilegroup II showed insignificant increase. The three tested groups showed significant increase in surface roughnessvalues and significant reduction in microhardness after acidic challenge. Conclusion: Resin infiltration andbleaching followed by resin infiltration reduced the surface roughness and enhanced the microhardness of theWSLs. The three treatment modalities failed to resist acidic challenge resulting in increasing surface roughnessand reducing microhardness.KEYWORDSAFM; Bleaching; Microhardness; Resin infiltration; White spot lesions.

Enhanced Enamel Whitening, Surface Hardness and Stain Resistance by 9.3-µm CO2 Laser Irradiation: An In-Vitro Pilot Study

Objectives: In vitro studies were performed to investigate the effects of irradiating incisor enamel with a 9.3 µm CO2 laser in enhancement of whiting, stain resistance and surface hardness. Methods: A 9.3 µm CO2 laser beam was used to irradiate the labial surface of incisors with 0.8 J/cm2 pulse fluence at 333 Hz automatically scanning a 5.8 mm2 area for 0.381 seconds repeated to cover the whole teeth surface. The teeth were divided into three groups of n=10 each: a control group that received 40% H2 O2 gel for 20-minutes application time, an irradiated group followed with two 10-minute gel applications, and another irradiated group followed with two 20-minute gel applications. A spectroscopy device was used to analyze the overall color change (delta E) and degree of whitening. A 24-hour tea stain protocol was used to investigate the uptake of stain after the treatment procedure. Additionally, a small flat polished area on each sample was used to investigate microhardness before and after an acid challenge with pH 3.6 citric acid buffer. Result: Both irradiated groups showed an enhanced whitening effect, with a delta E that was 1-2 higher than the H2 O2 gel control group. The 10-minute application time was sufficient to reach the full benefit from irradiation. The irradiated groups showed increased resistance to acid solubility and reduced the absorption of tea stain. Conclusion: Irradiation with a 9.3 µm CO2 laser before application of whitening gel on incisor enamel increased the effect of whitening in half the time. It also provided an increased resistance to acid attack and staining

Remineralization potential of gum arabic versus casein phosphopeptide–amorphous calcium phosphate–fluoride for demineralized enamel in acidic challenges: In vitro study

Remineralization potential of gum arabic versus casein phosphopeptide–amorphous calcium phosphate–fluoride for demineralized enamel in acidic challenges: In vitro study

60 - Temporal Assessment of Remineralizing Demineralized Enamel Using Micro-Computed Tomography

Remineralizing enamel is an important approach of treating early carious lesion without surgical intervention allowing for preservation of tooth structure. This study objective is longitudinal assessment of enamel microstructure using non-destructive micro-CT to monitor the remineralization process undergoing fluctuating changes in pH after treatment with different remineralization agents. Twelve human extracted premolars were collected. Calculus and soft tissue were removed from the root, kept in distilled water, and stored at 4 C. The teeth were screened using Swept Source OCT (SANTEC IVS-2000) to identify a 3 ×3 mm2 caries-free region of interest on the crown for artificial caries induction. The whole crown, except for the identified sound area, was coated with two layers of acid-resistant nail varnish. Then samples were mounted using acrylic resin and customized mounts to standardize successive scans with micro-Ct. Each mounted sample was incubated in 20 ml of buffered lactic acid (2.2 mM CaCl 2 , 2.2 mM K 2 HPO 4 , 0.1 M Lactic acid adjusted pH to 4.5) for 72 hours in 37 C to induce caries-like lesions of approximately 100 micron in depth. After 72 hours, the samples were rinsed with deionized water and stored in distilled water to be scanned. The samples were grouped into four groups (n=3) that consist of three intervention groups and one negative control group. The 3 intervention groups consist of two fluoride varnish and one polypeptide-based remineralization agents. Each sample received the remineralizing treatment after the lesion formation according to manufacturers instructions. After that all samples were subjected to pH cycling for 2 weeks in 37 C incubation on a shaker table. Ph cycling solutions were refreshed at the end of every cycle following [ten Cate and Duijsters, 1982] protocol which is: 1-three hours in demineralization solution,2-rinse for 30 s with distilled water and 3- 21 hours in artificial saliva.Micro-Ct scans were carried out after 6 and 12 pH cycles. Lesion depth, ld and Delta Z, ΔZ were calculated The mean lesion depth developed in the different groups showed no noticeable difference after 6 ph. cycles while after 12 ph. cycles lesion depth were decreased in the different groups with more observable decrease in the experimental fluoride group. Both self-assembly peptide agent and experimental fluoride showed no further increase in the lesion depth after the acidic challenge at the end of the ph. cycles. Remineralized enamel with different remineralizing agents reacts differently under the same fluctuating ph. conditions at different time intervals.

Effect of Acidic Solutions on the Surface Roughness and Microhardness of Indirect Restorative Materials: A Systematic Review and Meta-analysis

To evaluate the effects of acidic solutions on the surface roughness (SR) and surface microhardness (SMH) of indirect restorative materials by analyzing in vivo and in vitro studies. Studies comparing the SR and SMH of indirect restorative materials after erosion were included in the meta-analysis. Meta-analyses were conducted with a random-effects model at a significance level of P < .05 using Review Manager software (Cochrane Collaboration). The literature search was conducted using Web of Science, MEDLINE (PubMed), and the Cochrane Library, with no limitations on publication year. Of the 1,097 potentially relevant studies, 32 full-text articles were assessed for eligibility. A total of 16 articles were included in the systematic review, and 15 were included in the meta-analyses. The kappa score between the two reviewers was 0.80. The effects of erosion on ceramics, indirect composites, and hybrid ceramics were evaluated by immersion in or rinsing with acidic solutions (eg, hydrochloric acid [HCl], cola drinks, and juices). An increase in the SR (Ra values) (P < .00001; mean difference [MD] = -0.04; 95% CI = -0.06 to -0.03) and a decrease in the SMH (Vickers microhardness) (P < .00001; MD = 13.94; 95% CI = 12.33 to 15.55) were found after erosion. Subgroup analyses revealed that in vitro erosion led to significantly higher Ra values and lower VHN values than in vivo erosion; cola drinks and juices led to more surface degradation than HCl; and the SR and SMH of polymer-infiltrated ceramic network (PICN) materials remained unchanged after erosion. After acidic challenges, a significantly rougher and softened surface was found for indirect restorative materials. Among all the indirect restorative materials, PICN showed the best acid resistance. Nevertheless, the changes in the SR and SMH of indirect restorative materials after erosion detected in the present study were minor and may not have any clinical significance.

Effect of the cranberry ( Vaccinium macrocarpon ) juice on reducing dentin erosion: an in vitro study.

Vaccinium macrocarpon (cranberry) is a fruit that has an inhibitory effect on matrix metalloproteinases (MMPs) present in dentin and saliva. The inhibition of MMPs has been shown to prevent dentin erosion. The aim of this study was to analyze the effect of cranberry juice on the reduction of dentin erosion in vitro. Specimens of bovine dentin (4×4×2 mm) were randomized and divided into 4 groups (n = 17/group): distilled water (C-control, pH 7.2); green tea extract solution containing 400 µm epigallo-catechin-gallate (EGCg, positive control, pH 4.5); 10% cranberry extract (CrE, pH 3.9), and cranberry juice (CrJ, Cranberry JuxxTM, pH 2.8). Specimens were submitted to erosive pH cycles for 5 days. Each day, four demineralizations were carried out with 0.1% citric acid (90 s). After the acid challenges, specimens were rinsed and kept in treatment solutions for 1 min; afterwards, they were rinsed and stored in artificial saliva for 1 h at 37°C (or overnight at the end of each day). After the experimental period of 5 days, dentin loss was evaluated by contact profilometry. Data were analyzed by ANOVA and Tukey's test (p < 0.05). Dentin loss (µm ± SD) was significantly lower for all treatments (EGCg = 9.93 ± 2.90; CrE = 12.10 ± 5.44; CrJ = 11.04 ± 5.70) compared to control (21.23 ± 11.96), but it did not significantly differ from each other. These results indicate that the commercial cranberry juice, despite its low pH, is able to reduce dentin erosion, which might be due to the ability of cranberry components to inhibit MMPs.

Fibroblast-specific activation of Rnd3 protects against cardiac remodeling in diabetic cardiomyopathy via suppression of Notch and TGF-β signaling.

Rationale: Extracellular matrix (ECM) remodeling, a key pathological feature in diabetic cardiomyopathy (DCM), is triggered by oxidative stress, inflammation, and various metabolic disorders in the heart. Cardiac fibroblasts (CFs) are the primary source of ECM proteins and the ultimate effector cells in ECM remodeling. CFs are turned on and differentiated into myofibroblasts in response to profibrotic signaling. Rnd3 is a small Rho-GTPase involved in the regulation of cell-cycle distribution, cell migration, and cell morphogenesis. Emerging evidence suggests a link between Rnd3 expression and onset of cardiovascular diseases. However, the role of Rnd3 in DCM remains unknown. Methods: Flow cytometry was employed to separate different types of cardiac cells. Type 2 diabetes mellitus was established in Rnd3 fibroblast-specific knockout and transgenic mice. RNA sequencing and chromatin immunoprecipitation assay were used to discern signaling pathways involved. Results: Rnd3 expression was reduced in cardiac tissues of diabetic mice, with CFs being the primary cell type. Fibroblast-specific upregulation of Rnd3 in vivo was protective against DCM, whereas Rnd3 downregulation in fibroblasts accentuated cardiac oxidative stress, fibrosis, ventricular remodeling, and dysfunction. Moreover, in vitro Rnd3 overexpression significantly attenuated reactive oxygen species production, CF migration and proliferation under high levels of glucose (35 mmol/L) and palmitic acid (500 µmol/L) challenge. Furthermore, RNA sequencing indicated that Notch and TGF-β signaling were significantly suppressed upon Rnd3 overexpression. Mechanistically, Rnd3 regulated Notch and TGF-β signaling by interacting with NICD and ROCK1, respectively. Specifically, glucotoxicity and lipotoxicity control Rnd3 expression by regulating the binding of Nr1H2 and Rnd3 promoter. Conclusions: Our findings provide compelling evidence in that fibroblast-specific activation of Rnd3 protects against cardiac remodeling in DCM, indicating promises of targeting Rnd3 in the treatment of DCM.

Remineralization Efficiency of Different Toothpastes on Human Enamel Subjected to Acid Challenge: in Vitro Study

Remineralization Efficiency of Different Toothpastes on Human Enamel Subjected to Acid Challenge: in Vitro Study

Endogenous Insulin: Study on Pain Threshold through Opioid Mechanism in Swiss Albino Mice

<p style="text-align: justify;"><strong>Background:</strong> There is no definitive conclusion on relationship between insulin and pain threshold through opioid mechanism in experimental animal model. The present study investigated the role of endogenous insulin in the modulation of pain using opioid drugs through opioid mechanism and their relationship in experimental animal model. <strong>Methods:</strong> Eight animal groups were used, each group consisting of six mice (Swiss albino). Group 1-treated saline ip; Group 2- administered pentazocine ip; Group 3- treated naloxone in low dose (0.005 mg/kg, ip) 15 min prior to pentazocine treatment; Group 4- administered naloxone in high dose (5 mg/kg, ip)15 min prior to pentazocine treatment. Another four groups of animals (Group 5, 6, 7 and 8) treated saline, pentazocine, low dose and high dose naloxone both administered 15 min prior to pentazocine treatment respectively. Group 1,2,3 and 4 subjected to acetic acid challenge and Group 5,6, 7 and 8 subjected to formalin test. Blood samples were collected and serum insulin was estimated by ELISA and blood glucose was measured by using Ames glucometer. <strong>Results:</strong> Pentazocine significantly increased both serum insulin and antinociceptive response to nociceptive stimuli to acetic acid as well as formalin challenge without significantly affecting plasma glucose in both pain models as compared to saline control. <strong>Conclusion: </strong>The study concluded that possible association between endogenous insulin and pain threshold which is independent of the glycemic status in both the chemically induced nociceptive tests. The relationship between endogenous insulin and pain threshold involves an interaction with opioid system possibly by binding with kappa receptor. <strong>Key words: </strong>Endogenous insulin, Plasma glucose, Pentazocine, Pain thresholds, Mice.

Effect of experimental moringa and propolis toothpastes on surface microhardness of simulated hypersensitive dentin

ObjectiveObjective was to investigate the effect of NovaMin toothpaste and two experimental toothpastes on surface microhardness of hypersensitive dentin.MethodsEighty specimens were prepared and divided randomly into eight groups (n = 10/group) according to the tested toothpastes (NovaMin, moringa and propolis toothpastes) and the acidic challenge (with or without 6% citric acid challenge). Enamel surfaces were removed, and the dentin surfaces were exposed on which the three tested toothpastes were brushed twice a day for 1 week using an electric toothbrush, then a 4-d citric acid cycling model with pH 5 was performed. The prepared specimens were stored in artificial saliva until the microhardness test was performed. Statistical analysis was done using One-way ANOVA followed by Tukey post hoc test.ResultsNovaMin-containing toothpaste showed an increased dentin surface microhardness following a week of twice daily brushing compared to other groups. However, NovaMin-containing toothpaste showed the highest microhardness values following pH cycling with citric acid of pH 5 compared to other tested groups.ConclusionsNovaMin-containing toothpaste showed a partial recovery of dentin microhardness at pH 5 during the acidic challenge. Moreover, propolis- and moringa-containing toothpastes had an insignificant effect on dentin surface microhardness with and without citric acid challenge.

Anti-Acid Biomimetic Dentine Remineralization Using Inorganic Silica Stabilized Nanoparticles Distributed Electronspun Nanofibrous Mats.

BackgroundTo manage the sharp pain of dentine hypersensitivity, various materials are utilized to conduct dentine remineralization. However, many prior materials are limited with their single function and complicated operations. In this study, silica and calcium (strontium) carbonates mineralized nano cellulose fibrous (Si/Ca(Sr)-NCF) mat with the ability to release acid resistant and biomimetic mineralizational silica/calcium (strontium) carbonate co-precipitation nanoparticles (Si/Ca(Sr) NPs) were fabricated. The dentine occluding effects, antibacterial activity and cytocompatibility of the Si/Ca(Sr)-NCF mats were evaluated.MethodsThe Si/Ca(Sr)-NCF mats were fabricated by dipping the electrospun nano cellulose fiber (NCF) into silica and calcium (strontium) carbonate liquid. Physicochemical characterizations and ion release were confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ion release assays and transmission electron microscopy (TEM). Sixty dentine discs were randomly divided into five groups: 1, blank NCF; 2, Si/Ca(Sr 0)-NCF; 3, Si/Ca(Sr 0.01)-NCF; 4, Si/Ca(Sr 0.05)-NCF; 5, Si/Ca(Sr 0.1)-NCF. Dentine discs were mineralized by the mats and observed with SEM immediately, after acid challenge and remineralized in artificial saliva. The releasing liquid was investigated by TEM and type I collagen model. Then, antibacterial property and cytocompatibility were evaluated.ResultsSEM and TEM results confirmed that the experiment mats continuously released amorphous Si/Ca(Sr) NPs and consequently realized anti-acid dentine biomimetic remineralization. Homogeneous surface coverage and collagen intrafibrillar mineralization in strontium adding groups illustrated the mineralization effect was not only by in site precipitation, but also collagen heterogeneous nucleation. Additionally, acceptable antibacterial and cytocompatibility properties were illustrated in low and middle Sr2+ containing mats.ConclusionIn vitro studies on human dentine discs and type I collagen demonstrated that Si/Ca(Sr)–NCF system was a multifunction system inducing anti-acid, biomimetic, antibacterial and cytocompatible dentine remineralization. This multifunction mat would be a promising DH treatment candidate for complicated exposed dentine surfaces.

P.0340 Effects of interventions for anxiety on peripheral inflammation: a systematic review and meta-analysis

To develop an in situ model for erosive wear research which allows for more clinically relevant exposure parameters than other in situ models and to show tooth site-specific erosive wear effect of an acid challenge of orange juice on enamel.This pilot study included 6 edentulous volunteers wearing full dentures with 13 embedded enamel samples The study consisted of two control runs: habitual diet only for 30 days, and two experimental runs: habitual diet plus 125 ml orange juice four times per day (consumed over 4 m). In the first experimental run subjects were instructed to take the drink in their mouth and promptly swallow it. In the second experimental run subjects take the drink in their mouth and hold each 25 ml for 30 s, moving it around their mouth before swallowing. Sample enamel surface loss was measured using non-contact surface profilometry.Drinking of orange juice additional to the habitual diet, caused significant but low increased erosive wear at buccal, palatal and lingual specimens. Significantly higher levels of tissue loss were found on all surfaces in the swishing experiment but molars (especially occlusal specimens in mandibular molars), palatal specimens sited in upper anterior teeth and lingual specimens in lower anterior teeth were most affected.The model showed clinically relevant patterns of erosive tooth wear as seen clinically in erosive wear patients.The model could have many applications to study clinically erosive wear for specific diets or consumption patterns and to test preventive measures.