Effect of two desensitizing agents applied previous to in-office bleaching on the degree of whitening and dentin sensitivity: A randomized, controlled, double-blind clinical trial.

PURPOSE: To evaluate the effect of two desensitizing agents applied before in-office bleaching, on the degree of whitening and dentin sensitivity. METHODS: Participants were randomly assigned to the groups, according to the desensitizing agent used, with n=10 for each one. The bleaching was performed with 35% hydrogen peroxide, divided according to the desensitizing agent used prior to the bleaching procedure: Placebo (PL); Desensibilize KF with potassium nitrate and 0.2% sodium fluoride (PN); and Oxa-Gel with potassium oxalate (PO). The level of color saturation was assessed at the beginning of treatment and after 1 week of its completion by means of comparative method with the aid of a color scale. The degree of sensitivity (DS) was noted by the subjects with the aid of a visual scale throughout the time that the bleaching agent remained in contact with the teeth (5, 10, 15, 20, 25 and 30 minutes) as well as 1, 24 and 48 hours after the end of application. Pain and the degree of color saturation were evaluated using the Shapiro-Wilk test. The DS was assessed by Kruskal-Wallis and Dunn's tests. The color was evaluated by ANOVA and Tukey's HSD. RESULTS: There was no significant difference in the degree of bleaching among the groups. DS was significantly more accentuated in the 48-hour period. The DS was significantly higher for the PL group and significantly lower for the PO group. The desensitizing agents reduced the DS without affecting the effectiveness of the bleaching treatment. CLINICAL SIGNIFICANCE: Both desensitizing agents provided greater control over pain compared to the placebo group. Potassium oxalate showed greater pain control than potassium nitrate. Both desensitizing agents tested did not interfere in the degree of whitening.

Identity Conflict and Sexual Risk for Black and Latino YMSM.

Young (aged 18-30) Black and Latino men who have sex with men are at a higher risk of contracting HIV than their White counterparts. In order to better understand the unique nature of sexual risk-taking, we examined the extent to which ethnic group, ethnic identity, and sexual pride predicted condomless anal sex with casual partners among 161 young men who have sex with men (YMSM) who identify as Black or Latino. Negative binomial regressions were conducted using a cross-sectional design. Sexual pride was a negative predictor of condomless anal sex across all participants, but this effect was moderated by ethnic exploration and ethnic group; the relationship between sexual pride and condomless anal sex was strengthened by greater ethnic exploration among Latino YMSM, and weakened by greater ethnic exploration among Black YMSM. Implications for intersectional identity, identity conflict, and HIV prevention among young gay men of color are discussed.

The Reelin receptor ApoER2 is a cargo for the adaptor protein complex AP-4: Implications for Hereditary Spastic Paraplegia.

Adaptor protein complex 4 (AP-4) is a heterotetrameric complex that promotes export of selected cargo proteins from the trans-Golgi network. Mutations in each of the AP-4 subunits cause a complicated form of Hereditary Spastic Paraplegia (HSP). Herein, we report that ApoER2, a receptor in the Reelin signaling pathway, is a cargo of the AP-4 complex. We identify the motif ISSF/Y within the ApoER2 cytosolic domain as necessary for interaction with the canonical signal-binding pocket of the µ4 (AP4M1) subunit of AP-4. AP4E1- knock-out (KO) HeLa cells and hippocampal neurons from Ap4e1-KO mice display increased co-localization of ApoER2 with Golgi markers. Furthermore, hippocampal neurons from Ap4e1-KO mice and AP4M1-KO human iPSC-derived cortical i3Neurons exhibit reduced ApoER2 protein expression. Analyses of biosynthetic transport of ApoER2 reveal differential post-Golgi trafficking of the receptor, with lower axonal distribution in KO compared to wild-type neurons, indicating a role of AP-4 and the ISSF/Y motif in the axonal localization of ApoER2. Finally, analyses of Reelin signaling in mouse hippocampal and human cortical KO neurons show that AP4 deficiency causes no changes in Reelin-dependent activation of the AKT pathway and only mild changes in Reelin-induced dendritic arborization, but reduces Reelin-induced ERK phosphorylation, CREB activation, and Golgi deployment. This work thus establishes ApoER2 as a novel cargo of the AP-4 complex, suggesting that defects in the trafficking of this receptor and in the Reelin signaling pathway could contribute to the pathogenesis of HSP caused by mutations in AP-4 subunits.

Performance of ChatGPT, Bard, Claude, and Bing on the Peruvian National Licensing Medical Examination: a cross-sectional study.

PURPOSE: We aimed to describe the performance and evaluate the educational value of justifications provided by artificial intelligence chatbots, including GPT-3.5, GPT-4, Bard, Claude, and Bing, on the Peruvian National Medical Licensing Examination (P-NLME). METHODS: This was a cross-sectional analytical study. On July 25, 2023, each multiple-choice question (MCQ) from the P-NLME was entered into each chatbot (GPT-3, GPT-4, Bing, Bard, and Claude) 3 times. Then, 4 medical educators categorized the MCQs in terms of medical area, item type, and whether the MCQ required Peru-specific knowledge. They assessed the educational value of the justifications from the 2 top performers (GPT-4 and Bing). RESULTS: GPT-4 scored 86.7% and Bing scored 82.2%, followed by Bard and Claude, and the historical performance of Peruvian examinees was 55%. Among the factors associated with correct answers, only MCQs that required Peru-specific knowledge had lower odds (odds ratio, 0.23; 95% confidence interval, 0.09-0.61), whereas the remaining factors showed no associations. In assessing the educational value of justifications provided by GPT-4 and Bing, neither showed any significant differences in certainty, usefulness, or potential use in the classroom. CONCLUSION: Among chatbots, GPT-4 and Bing were the top performers, with Bing performing better at Peru-specific MCQs. Moreover, the educational value of justifications provided by the GPT-4 and Bing could be deemed appropriate. However, it is essential to start addressing the educational value of these chatbots, rather than merely their performance on examinations.

The Reelin Receptor ApoER2 is a Cargo for the Adaptor Protein Complex AP-4: Implications for Hereditary Spastic Paraplegia.

Adaptor protein complex 4 (AP-4) is a heterotetrameric complex that promotes protein export from the trans -Golgi network. Mutations in each of the AP-4 subunits cause a complicated form of Hereditary Spastic Paraplegia (HSP). Herein, we report that ApoER2, a receptor in the Reelin signaling pathway, is a cargo of the AP-4 complex. We identify the motif ISSF/Y within the ApoER2 cytosolic domain as necessary for interaction with the canonical signal-binding pocket of the µ4 (AP4M1) subunit of AP-4. AP4E1 -knock-out (KO) HeLa cells and hippocampal neurons from Ap4e1 -KO mice display increased Golgi localization of ApoER2. Furthermore, hippocampal neurons from Ap4e1 -KO mice and AP4M1 -KO human iPSC-derived cortical i3Neurons exhibit reduced ApoER2 protein expression. Analyses of biosynthetic transport of ApoER2 reveal differential post-Golgi trafficking of the receptor, with lower axonal distribution in KO compared to wild-type neurons, indicating a role of AP-4 and the ISSF/Y motif in the axonal localization of ApoER2. Finally, analyses of Reelin signaling in mouse hippocampal and human cortical KO neurons show that AP4 deficiency causes no changes in Reelin-dependent activation of the AKT pathway and only mild changes in Reelin-induced dendritic arborization, but reduces Reelin-induced ERK phosphorylation, CREB activation, and Golgi deployment. Altogether, this work establishes ApoER2 as a novel cargo of the AP-4 complex, suggesting that defects in the trafficking of this receptor and in the Reelin signaling pathway could contribute to the pathogenesis of HSP caused by mutations in AP-4 subunits.

Antimicrobial and Antibiofilm Capacity of Chitosan Nanoparticles against Wild Type Strain of Pseudomonas sp. Isolated from Milk of Cows Diagnosed with Bovine Mastitis.

Bovine mastitis (BM) is the most prevalent bacterial infection in the livestock sector, affecting the dairy industry greatly. The prevention and treatment of this disease is mainly made via antibiotics, but the increasing antimicrobial resistance of pathogens has affected the efficiency of conventional drugs. Pseudomonas sp. is one of the pathogens involved in this infection. The therapeutic rate of cure for this environmental mastitis-causing pathogen is practically zero, regardless of treatment. Biofilm formation has been one of the main virulence mechanisms of Pseudomonas hence presenting resistance to antibiotic therapy. We have manufactured chitosan nanoparticles (NQo) with tripolyphosphate (TPP) using ionotropic gelation. These NQo were confronted against a Pseudomonas sp. strain isolated from milk samples of cows diagnosed with BM, to evaluate their antimicrobial and antibiofilm capacity. The NQo showed great antibacterial effect in the minimum inhibitory concentrations (MIC), minimum bactericidal concentration (MBC) and disk diffusion assays. Using sub lethal concentrations, NQo were tested for inhibition of biofilm formation. The results show that the nanoparticles exhibited biofilm inhibition and were capable of eradicate pre-existing mature biofilm. These findings indicate that the NQo could act as a potential alternative to antibiotic treatment of BM.

Cardiovascular risk assessment in the resource limited setting of Western Honduras: An epidemiological perspective.

Cardiovascular Disease (CVD) epidemiology varies significantly among Low and Middle-Income Countries. Honduras is the Central American country with the highest Ischemic Heart Disease and CVD mortality rates. The aim of this study was to assess the individual CVD risk factors and calculate Cardiovascular Risk Assessment Scores (CVRAS) from the population. Methods: A cross-sectional study in western Honduras. Estimation of CV risk was performed using Framingham, MESA, ACC/AHA-PCEs and ESC SCORE calculators. Results: 38% were male. For men and women respectively; 49% and 48% had self-reported hypertension (HTN), on measured blood pressure only 18% and 30% had normal readings. Diabetes Mellitus was reported in 19% and 22%. Tobacco use was 14% and 3%. Self-reported regular exercise was 39.9% and 25%. Obesity was diagnosed in 24% and 24%. Lipid profile; total cholesterol was ≥200 mg/dl in 63% of subjects. LDL-C was elevated (>100 mg/dl) in 74% of participants, 9% had LDL-C levels higher than 190 mg/dl. Triglycerides were high (>160 mg/dl) in 60%, of these subjects 22% were taking lipid-lowering medications. 52% reported family-history of CVD. The risk calculation for men and women respectively for each CVRAS were; AHA/ACC-PCEs high risk (score ≥ 7.5%) in 62% and 30%, FRS high risk (score ≥ 20%) 46% and 15%, MESA high risk (Score ≥ 7.5%) in 70.6% and 17.7%, ESC SCORE high risk (score ≥ 5% in 32.4% and 11.8%). Conclusions: CV risk calculations revealed higher than rates than expected with consequently reflected on higher than estimated CVRAS. This represents the first report of its kind in Honduras.

Enhancement of proton transfer in ion channels by membrane phosphate headgroups.

The transfer of protons (H+) in gramicidin (gA) channels is markedly distinct in monoglyceride and phospholipid membranes. In this study, the molecular groups that account for those differences were investigated using a new methodology. The rates of H+ transfer were measured in single gA channels reconstituted in membranes made of plain ceramides or sphingomyelins and compared to those in monoglyceride and phospholipid bilayers. Single-channel conductances to protons (gH) were significantly larger in sphingomyelin than in ceramide membranes. A novel and unsuspected finding was that H+ transfer was heavily attenuated or completely blocked in ceramide (but not in sphingomyelin) membranes in low-ionic-strength solutions. It is reasoned that H-bond dynamics at low ionic strengths between membrane ceramides and gA makes channels dysfunctional. The rate of H+ transfer in gA channels in ceramide membranes is significantly higher than that in monoglyceride bilayers. This suggests that solvation of the hydrophobic surface of gA channels by two acyl chains in ceramides stabilizes the gA channels and the water wire inside the pore, leading to an enhancement of H+ transfer in relation to that occurring in monoglyceride membranes. gH values in gA channels are similar in ceramide and monoglyceride bilayers and in sphingomyelin and phospholipid membranes. It is concluded that phospho headgroups in membranes have significant effects on the rate of H+ transfer at the membrane gA channel/solution interfaces, enhancing the entry and exit rates of protons in channels.

Causal Inference in Generalizable Environments: Systematic Representative Design.

Causal inference and generalizability both matter. Historically, systematic designs emphasize causal inference, while representative designs focus on generalizability. Here, we suggest a transformative synthesis - Systematic Representative Design (SRD) - concurrently enhancing both causal inference and "built-in" generalizability by leveraging today's intelligent agent, virtual environments, and other technologies. In SRD, a "default control group" (DCG) can be created in a virtual environment by representatively sampling from real-world situations. Experimental groups can be built with systematic manipulations onto the DCG base. Applying systematic design features (e.g., random assignment to DCG versus experimental groups) in SRD affords valid causal inferences. After explicating the proposed SRD synthesis, we delineate how the approach concurrently advances generalizability and robustness, cause-effect inference and precision science, a computationally-enabled cumulative psychological science supporting both "bigger theory" and concrete implementations grappling with tough questions (e.g., what is context?) and affording rapidly-scalable interventions for real-world problems.

Virtually 'in the heat of the moment': insula activation in safe sex negotiation among risky men.

HIV is most prevalent among men who have sex with men (MSM), and although most MSM use condoms consistently during casual sex, some take risks. To better understand the psychology of those risky decisions, we examined neural correlates of playing a virtual sexual 'hook up' game in an functional magnetic resonance imaging scanner in MSM who had, in the past 90 days, been sexually risky (N = 76) or safe (N = 31). We found that during potentially risky sexual choices, previously risky MSM had more right insula activity than previously safe MSM. Real-life sexual risk was related to trait positive and negative urgency. Insula activity that differentiated risky and safe MSM was related to trait positive and negative urgency. Future work should further examine if, and to what extent, insula activation during safe sex negotiation drives MSM's rash risky sexual decision-making.

Heparin Oligosaccharides Have Antiarrhythmic Effect by Accelerating the Sodium-Calcium Exchanger.

Background: Blockage of the Na+/Ca2+ exchanger (NCX) is used to determine the role of NCX in arrhythmogenesis. Trisulfated heparin disaccharide (TD) and Low Molecular Weight Heparins (LMWHs) can directly interact with the NCX and accelerate its activity. Objective: In this work, we investigated the antiarrhythmic effect of heparin oligosaccharides related to the NCX activity. Methods: The effects of heparin oligosaccharides were tested on the NCX current (patch clamping) and intracellular calcium transient in rat cardiomyocytes. The effects of heparin oligosaccharides were further investigated in arrhythmia induced in isolated rat atria and rats in vivo. Results: The intracellular Ca2+ concentration decreases upon treatment with either enoxaparin or ardeparin. These drugs abolished arrhythmia induction in isolated atria. The NCX antagonist KB-R7943 abolished the enoxaparin or ardeparin antiarrhythmic effects in isolated atria. In the in vivo measurements, injection of TD 15 min both before coronary occlusion or immediately after reperfusion, significantly prevented the occurrence of reperfusion-induced arrhythmias (ventricular arrhythmia and total AV block) and reduced the lethality rate. The patch clamping experiments showed that, mechanistically, TD increases the forward mode NCX current. Conclusion: Together, the data shows that heparin oligosaccharides may constitute a new class of antiarrhythmic drug that acts by accelerating the forward mode NCX under calcium overload.

A new strategy for direct measurement of sinus atrial conduction time by sinus node threshold determination in a rat-isolated atrium.

In this work we have searched for experimental evidence that would corroborate the idea that nodal threshold (NT) is the minimum electric field strength able to promote direct sinus node reset that, in turn, can be verified by a decrease in corrected sinus node recovery time (CSNRT). We have performed direct measurements of sinus node conduction time (SACT) and estimation of atrium sinus conduction time (ASCT). Stimulating pulses (pulse and train methods) generated a uniform electric field, with strength ranging from 1.5-fold to 5-fold the atrial threshold (AT), in the center of the perfusion chamber where isolated right atria were placed. The AT and NT were 67.4 and 192.7 mV cm(-1), respectively. The CSNRT values, obtained with stimulation strength below or above NT, were, respectively (ms; mean +/- standard error of mean) 38.1 +/- 0.42 and 25.2 +/- 0.30. In addition, we verified that NT corresponds to approximately 3-fold the AT; SACT was 1.34-fold ASCT and the overdrive suppression decreases with the increment of stimulation pulse strength. Therefore, by using a new and accurate approach for SNRT determination, we have provided additional experimental evidence for the development of alternative sinus node evaluation methods.

Evidencia clínica e histológica de regeneración de tejido blando a partir de una matriz colágena porcina. Reporte de Caso / Histological and clinical evidence of soft tissue regeneration from a porcine collagen matrix. Case Report

RESUMEN: La pérdida de un diente resulta en la pérdida de volumen de tejidos duros y blandos lo que dificulta lograr resultados estéticamente satisfactorios. Con el fin de disminuir la morbilidad que provoca un injerto autólogo en el sellado del alveolo se puede reemplazar por una matriz reabsorbible de colágeno. El presente reporte de caso evaluó clínica e histológicamente una matriz colágena de porcino, en la regeneración de tejido blando, durante la instalación de un implante inmediato a una extracción dentaria. A los 6 meses clínicamente se obtuvo un tejido con una apariencia estética final óptima e histológicamente se evidenció la formación de un tejido epitelial y conjuntivo compatible con la de una mucosa normal.

ABSTRACT: Tooth loss results in loss of hard and soft tissue volume, making it difficult to achieve aesthetically pleasing results. In order to decrease the morbidity caused by an autologous graft in the alveolus seal, it can be replaced by a resorbable matrix of collagen. The present case report evaluated clinically and histologically a porcine collagen matrix, in soft tissue regeneration, during the installation of an implant immediately after dental extraction. At 6 months, clinically, a tissue with an optimal final aesthetic appearance was obtained and histologically, the formation of an epithelial and connective tissue compatible with that of a normal mucosa was evidenced.

A segmentation method for myocardial ischemia/infarction applicable in heart photos.

The myocardial infarction, known as heart attack, is the ultimate result of a prolonged/untreated cardiac ischemia. The accurate segmentation of the myocardial infarction or ischemia in images obtained from diversified sources, such as Magnetic Resonance Images or Echocardiograph, is worthwhile for the medical area or the animal experimentation. An alternative image source for ischemia/infarction segmentation is the photo, which can depict the actual heart image. This work presents a method for ischemia segmentation in rat heart photos. The method applicability was tested in pictures of human hearts available in public databases from the Internet. At first, heart images were separated from the background using GrabCut method. Secondly, the segmentation of the cardiac ischemia region was performed by using Fuzzy Clustering method. Finally, a sequence of image processing (including morphological operations to remove small components and to fill the holes) was performed to obtain the final segmentation image. All resulting images were compared with the corresponding images containing contours of cardiac ischemia drawn manually by specialists. The mean accuracy was 83.24% ± 04.16%. As for the intrinsically human errors (tracing error between two specialists: 18.94% ± 05.30%), the average accuracy is within the inter-operator variability. As for the human heart pictures obtained from public libraries, the algorithm segmented the infarction areas correctly. The results show that the algorithm effectively helps the visualization of the cardiac ischemia/infarction region and has the potential to be applied to heart images of animals or humans, representing a versatile tool to assist advances in cardiomyopathology studies.

Severe impacts of brown tides caused by Sargassum spp. on near-shore Caribbean seagrass communities.

From mid-2014 until the end of 2015, the Mexican Caribbean coast experienced a massive influx of drifting Sargassum spp. that accumulated on the shores, resulting in build-up of decaying beach-cast material and near-shore murky brown waters (Sargassum-brown-tides, Sbt). The effects of Sbt on four near-shore waters included reduction in light, oxygen (hypoxia or anoxia) and pH. The monthly influx of nitrogen, and phosphorus by drifting Sargassum spp. was estimated at 6150 and 61kgkm-1 respectively, resulting in eutrophication. Near-shore seagrass meadows dominated by Thalassia testudinum were replaced by a community dominated by calcareous rhizophytic algae and drifting algae and/or epiphytes, resulting in 61.6-99.5% loss of below-ground biomass. Near-shore corals suffered total or partial mortality. Recovery of affected seagrass meadows may take years or even decades, or changes could be permanent if massive influxes of Sargassum spp. recur.

Trisulfate Disaccharide Decreases Calcium Overload and Protects Liver Injury Secondary to Liver Ischemia/Reperfusion.

BACKGROUND: Ischemia and reperfusion (I/R) causes tissue damage and intracellular calcium levels are a factor of cell death. Sodium calcium exchanger (NCX) regulates calcium extrusion and Trisulfated Disaccharide (TD) acts on NCX decreasing intracellular calcium through the inhibition of the exchange inhibitory peptide (XIP). OBJECTIVES: The aims of this research are to evaluate TD effects in liver injury secondary to I/R in animals and in vitro action on cytosolic calcium of hepatocytes cultures under calcium overload. METHODS: Wistar rats submitted to partial liver ischemia were divided in groups: CONTROL: (n = 10): surgical manipulation with no liver ischemia; Saline: (n = 15): rats receiving IV saline before reperfusion; and TD: (n = 15): rats receiving IV TD before reperfusion. Four hours after reperfusion, serum levels of AST, ALT, TNF-α, IL-6, and IL-10 were measured. Liver tissue samples were collected for mitochondrial function and malondialdehyde (MDA) content. Pulmonary vascular permeability and histologic parameters of liver were determined. TD effect on cytosolic calcium was evaluated in BRL3A hepatic rat cell cultures stimulated by thapsigargin pre and after treatment with TD. RESULTS: AST, ALT, cytokines, liver MDA, mitochondrial dysfunction and hepatic histologic injury scores were less in TD group when compared to Saline Group (p<0.05) with no differences in pulmonary vascular permeability. In culture cells, TD diminished the intracellular calcium raise and prevented the calcium increase pre and after treatment with thapsigargin, respectively. CONCLUSION: TD decreases liver cell damage, preserves mitochondrial function and increases hepatic tolerance to I/R injury by calcium extrusion in Ca2+ overload situations.

The effects of electrode position on the excitability of rat atria during postnatal development.

Cardiac excitability is determined by the direction of the electric field, which is defined by the positioning of electrodes. However, important morphological and physiological modifications that happen during the postnatal development of the heart may affect the cardiac threshold. In this work we have evaluated the effect of electrode positioning on the excitability threshold of isolated Wistar rat atria (left auricles) during postnatal development. This was performed by determining the parameters of strength-duration curves for stimuli (rheobase, chronaxie and normalized minimum pulse energy) of atria from rats at ages (days) 5, 15, 30, 60, 90 and 120. These parameters were determined using electric field stimulation in four different orientations (apex-base, base-apex, left-right and right-left). Atrial rheobase decreased by 1.5- to 4-fold with animal age and was altered by electric field orientation in a diversified way, whereas atrial chronaxie increased only with animal age. The minimum pulse energy decreased two- to nine-fold with ageing. This was mainly due to rheobase dependence with electric field direction. We showed that the appropriate cardiac stimulation depends on the effects of three combined factors (pulse parameters, electrode position and animal age) on the atrial tissue excitability.

Regeneración de tejido blando en una clase 3 mediante un colgajo desplazado lateral e injerto de tejido conjuntivo. Reporte de un caso clínico / Elian class 3 regeneration of soft tissue using a laterally moved flap and connective tissue graft. A clinical case report

RESUMEN: Se describe el caso clínico de una paciente de 60 años, sexo femenino, sana, la cual presentaba en el diente 1.1 una recesión de 6 mm de longitud con extensa pérdida ósea en vestibular correspondiente a una clase 3 de Elian. En el presente reporte se expone los pasos que se siguieron para llegar a una Clase 2 de Elian, mediante un colgajo desplazado lateral con injerto de tejido conjuntivo subepitelial.

ABSTRACT: We describe the clinical case of a 60-year-old female patient, healthy, who presented a 6mm-long recession on tooth 1.1 with extensive vestibular bone loss corresponding to an Elian class 3. In the present report, the steps followed to reach an Elian class 2,by means of a laterally moved flap with subepithelial connective tissue graft, are shown.