VRK1 variants at the cross road of Cajal body neuropathogenic mechanisms in distal neuropathies and motor neuron diseases.

Distal hereditary neuropathies and neuro motor diseases are complex neurological phenotypes associated with pathogenic variants in a large number of genes, but in some the origin is unknown. Recently, rare pathogenic variants of the human VRK1 gene have been associated with these neurological phenotypes. All VRK1 pathogenic variants are recessive, and their clinical presentation occurs in either homozygous or compound heterozygous patients. The pathogenic VRK1 gene pathogenic variants are located in three clusters within the protein sequence. The main, and initial, shared clinical phenotype among VRK1 pathogenic variants is a distal progressive loss of motor and/or sensory function, which includes diseases such as spinal muscular atrophy, Charcot-Marie-Tooth, amyotrophic lateral sclerosis and hereditary spastic paraplegia. In most cases, symptoms start early in infancy, or in utero, and are slowly progressive. Additional neurological symptoms vary among non-related patients, probably because of their different VRK1 variants and their genetic background. The underlying common pathogenic mechanism, by its functional impairment, is a likely consequence of the roles that the VRK1 protein plays in the regulation on the stability and assembly of Cajal bodies, which affect RNA maturation and processing, neuronal migration of RNPs along axons, and DNA-damage responses. Alterations of these processes are associated with several neuro sensory or motor syndromes. The clinical heterogeneity of the neurological phenotypes associated with VRK1 is a likely consequence of the protein complexes in which VRK1 is integrated, which include several proteins known to be associated with Cajal bodies and DNA damage responses. Several hereditary distal neurological diseases are a consequence of pathogenic variants in genes that alter these cellular functions. We conclude that VRK1-related distal hereditary neuropathies and motor neuron diseases represent a novel subgroup of Cajal body related neurological syndromes.

Clinical Value of Serial Quantitative Analysis of Cytomegalovirus DNA in Blood and Saliva Over the First 24 Months of Life in Congenital Infection: The French Cymepedia Cohort.

OBJECTIVE: To evaluate cytomegalovirus (CMV) viral load dynamics in blood and saliva during the first 2 years of life in symptomatic and asymptomatic infected infants and to identify whether these kinetics could have practical clinical implications. STUDY DESIGN: The Cymepedia cohort prospectively included 256 congenitally infected neonates followed for 2 years. Whole blood and saliva were collected at inclusion and months 4 and 12, and saliva at months 18 and 24. Real-time CMV polymerase chain reaction (PCR) was performed, results expressed as log10 IU/mL in blood and in copies per milliliter in saliva. RESULTS: Viral load in saliva progressively decreased from 7.5 log10 at birth to 3.3 log10 at month 24. CMV PCR in saliva was positive in 100% and 96% of infants at 6 and 12 months, respectively. In the first month of life, neonatal saliva viral load of less than 5 log10 was related to a late CMV transplacental passage. Detection in blood was positive in 92% of neonates (147/159) in the first month of life. No viral load threshold values in blood or saliva could be associated with a high risk of sequelae. Neonatal blood viral load of less than 3 log10 IU/mL had a 100% negative predictive value for long-term sequelae. CONCLUSIONS: Viral loads in blood and saliva by CMV PCR testing in congenital infection fall over the first 24 months. In this study of infants affected mainly after primary maternal infection during pregnancy, all salivary samples were positive in the first 6 months of life and sequelae were not seen in infants with neonatal blood viral load of less than 3 log10 IU/mL.

Preclinical dental training: Association between fine motor skills and compliance with ergonomic posture techniques.

OBJECTIVE: The aim of this study was to evaluate the dental students' fine motor skills and their compliance with ergonomic posture techniques over the course of a preclinical training year. The correlation between fine motor skills and compliance was also assessed. METHODS: The ergonomic posture of students enrolled in the second year of a five-year undergraduate dental degree programme (n = 62) was assessed using the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). This assessment relied on photographs of the students performing preclinical laboratory procedures during the school year. The photographs of each procedure received a score, and the final score obtained (0 to 10) corresponded to the extent of the student's compliance with ergonomic posture techniques. Initial compliance was calculated during the first two months of the training programme, whilst final compliance was calculated during the last two months. Fine motor skills were evaluated using the modified Dental Manual Dexterity Assessment (DMDA), which was also applied at the beginning and the end of the school year. Data were assessed statistically by Student's paired t test, and the correlation between fine motor skills and compliance with ergonomic posture techniques was estimated by Pearson's correlation coefficient (r) and Student's t test (α = 0.05). RESULTS: The compliance scores were higher at the end of the academic year than at the beginning of year (p < 0.001; t = -5.300). Fine motor skills improved significantly with time (p < 0.001; t = -10.975). Non-significant correlations were found between students' fine motor skills and their economic posture compliance both at the beginning (r = -0.197; p = 0.126) and at the end of the training year (r = 0.226; p = 0.078). CONCLUSION: The students' manual dexterity and compliance with ergonomic posture techniques increased over the course of the preclinical training year, and the correlation between students' fine motor skills and their ergonomic posture compliance was not significant.

Stress amongst dental students in the transition from preclinical training to clinical training: A qualitative study.

OBJECTIVES: The present study sought to qualitatively evaluate third-year undergraduate dental students' perceptions of sources of stress during the transition from preclinical to clinical training. METHODS: This was an observational, cross-sectional, and qualitative study with a nonprobabilistic sampling design. The sample consisted of students in the third year of the five-year undergraduate degree program in dentistry offered by the São Paulo State University (UNESP), School of Dentistry, Araraquara, São Paulo State, Brazil (n = 37). Data were collected using open-ended, semistructured, and individual interviews that were recorded on a digital voice recorder. The students were interviewed on campus at a previously scheduled time. Efforts were made to provide a secure and welcoming environment for the interview. The interview questions addressed students' adaptation to clinical training and their perceptions of stress resulting from this transition. Data analysis was based on the qualitative and quantitative Discourse of the Collective Subject (DCS) technique performed with the aid of Qualiquantisoft®. RESULTS: Most of the students evaluated (75.7%) reported difficulty in the transition from the preclinical to the clinical phase of their program and that this difficulty increased their stress levels during this transition (81.1%). The most frequently cited reason for the increase in stress was the responsibility and demands associated with caring for real patients (54.1%). Almost half of the students (48.6%) reported feeling physical symptoms of stress such as tachycardia, dizziness, headache, and muscle tension during this period. Most of the students (81.1%) required up to one semester to feel that they had adapted to the clinic. Many students used stress reduction strategies such as simply trying to calm down, studying before their clinical work, improving organisation, and asking professors for help. Adaptation to ergonomics and biosafety in the clinic was the most frequently cited impediment (45.9%) to the adaptation process. The students' main suggestions for reducing stress in this transition phase were additional preclinical training in a clinical setting, a more gradual transition, and greater professor receptiveness. CONCLUSION: The dental students interviewed herein perceived high levels of stress during the transition from preclinical to clinical training.

Nanoparticle-mediated selective Sfrp-1 silencing enhances bone density in osteoporotic mice.

Osteoporosis (OP) is characterized by a loss in bone mass and mineral density. The stimulation of the canonical Wnt/ß-catenin pathway has been reported to promote bone formation, this pathway is controlled by several regulators as secreted frizzled-related protein-1 (Sfrp-1), antagonist of the pathway. Thus, Sfrp-1 silencing therapies could be suitable for enhancing bone growth. However, the systemic stimulation of Wnt/ß-catenin has been correlated with side effects. This work hypothesizes the administration of lipid-polymer NPs (LPNPs) functionalized with a MSC specific aptamer (Apt) and carrying a SFRP1 silencing GapmeR, could favor bone formation in OP with minimal undesired effects. Suitable SFRP1 GapmeR-loaded Apt-LPNPs (Apt-LPNPs-SFRP1) were administered in osteoporotic mice and their biodistribution, toxicity and bone induction capacity were evaluated. The aptamer functionalization of the NPs modified their biodistribution profile showing a four-fold increase in the bone accumulation and a ten-fold decrease in the hepatic accumulation compared to naked LPNPs. Moreover, the histological evaluation revealed evident changes in bone structure observing a more compact trabecular bone and a cortical bone thickness increase in the Apt-LPNPs-SFRP1 treated mice with no toxic effects. Therefore, these LPNPs showed suitable properties and biodistribution profiles leading to an enhancement on the bone density of osteoporotic mice.

Development and assessment of an indirect vision training programme for operatory dentistry: Effects on working posture.

OBJECTIVES: Students experience difficulty working with indirect vision and often adopt inadequate working postures because of it. This study created and then assessed the effects of an indirect vision preclinical training programme on dental students' working posture. METHODS: The study enrolled students in the third year of the 5-year undergraduate programme in dentistry in the School of Dentistry of São Paulo State University (UNESP), Araraquara (N = 54). The programme consisted of four training sessions in which students performed different types of activities in which only a mirror was used to see the procedure they were performing. To evaluate posture, students were asked to perform class III cavity preparations (distal-palatal and mesial-palatal preparations) on upper central and lateral incisors in a dental mannequin (tooth numbers 11, 12, 21 and 22) both before and after the indirect vision training programme. Photographs were taken of the students' working postures. The photographs were assessed by a duly trained researcher using the Compliance Assessment of Dental Ergonomic Posture Requirements. A descriptive statistical analysis was performed, and the assumptions of normality were verified. Student's paired t test was also performed. The significance level adopted was 5%. RESULTS: A significant difference was found between the percentages of correct ergonomic postures adopted before and after the training programme (p = 0.039). CONCLUSIONS: The preclinical training programme for indirect vision was found to have a positive effect on the working postures of the students evaluated herein.

Vibration attraction response is a plastic trait in blind Mexican tetra (Astyanax mexicanus), variable within subpopulations inhabiting the same cave.

Animals evolve their sensory systems and foraging behaviours to adapt and colonize new and challenging habitats such as the dark cave environment. Vibration attraction behaviour (VAB) gives fish the ability to locate the source of a water disturbance in the darkness. VAB evolved in the blind Mexican cave tetra, Astyanax mexicanus. VAB is triggered in cavefish by vibration stimuli peaking at 35 Hz, which is within the main spectrum of water fluctuations produced by many prey crustaceans and insects. VAB has a genetic component and is correlated to an increased number of head mechanosensory neuromasts in the eye orbital region when compared to surface fish. Previous competitive prey capture assays have supported the advantage of VAB for foraging in the dark. Despite its putative adaptive function, VAB has been described as absent in some Astyanax cave populations (Tinaja and Molino) but present in others (Pachón, Piedras, Toro and Sabinos). Here we have tested the occurrence of VAB in the field and in multiple cave populations using a vibrating device in natural pools. Our results confirmed the presence of VAB in caves such as Pachón, Toro and Sabinos but showed that VAB is also present in the Tinaja and Molino cave populations, previously reported as VAB-negative in laboratory experiments. Thus, VAB is available throughout the range of hypogean A. mexicanus. However, and most notably, within a given cave the levels of VAB were highly variable among different pools. Fish at one pool may express no VAB, while fish at another nearby pool of the same cave may actively show VAB. While a variety of environmental conditions may foster this diversity, we found that individuals inhabiting pools with a high abundance of organic matter have reduced expression of VAB. In contrast, in pools with little organic debris where fish probably depend more on hunting than on scavenging, VAB is enhanced. Our results suggest that expression of VAB is a plastic trait whose variability can depend on local conditions. Such plasticity may be required within and among caves where high environmental variability between pools results in a diverse availability of food.

Production of starch-polyester bio-support for lipases immobilization: synergistic action of itaconic acid and nanoclay.

The objective of the present work was to develop biodegradable polymeric films (starch-PBAT) as support for the immobilization of lipases using sodium montmorillonite (MMT) as a reinforcing agent (2% w/w) and itaconic acid (IA - 0.5-1.5% w/w) as a compatibilizing agent. The films were produced through a two steps blow-extrusion. The addition of MMT increased the tensile strength and Tg of the films, while the presence of IA made the films more flexible, reducing their Tg. Lipases from Burkholderia cepacia LTEB11 were immobilized in the films by the adsorption method. The ester yield (% of ethyl oleate synthesis) has shown best results (96%, 6 h) for immobilized enzyme in the MMT film and six cycles of reuse were carried out until a reduction of 50% in the catalytic activity of the enzyme.

Magnification loupes in dentistry: A qualitative study of dental students' perspectives.

INTRODUCTION: The nature of the oral operating field makes it a challenge for dentists to work while maintaining musculoskeletal health. Strategies have been studied in recent years to improve visualisation of the operating field, and the use of magnification systems has been recommended for providing additional benefits. Despite the growing body of evidence suggesting that the use of magnification improves visual acuity, the dentist's posture and the quality of dental procedures, few studies have analysed users' perspectives on these devices in terms of their adaptation process. These types of studies are important because they provide insight into the reality of the adaptation process required by magnification systems so that adjustments and improvements can be made to adapt these systems to the users' reality. Thus, we sought to explore the perspectives held by second-year students in an undergraduate dental program on the use of dental loupes during pre-clinical laboratory activities. MATERIALS AND METHODS: A total of 24 second-year dental students participated in semi-structured interviews exploring their perspectives of wearing dental loupes during their pre-clinical activities. Data collection and analysis were consistent with the qualitative content analysis methodology. All interview data were analysed using version 10 of the NVivo® analytical software. RESULTS: Participants described that magnification can lead to the improvement of their work postures, hand skills and quality of dental procedures. Nevertheless, they reported a need for an adaptation period and for adjustments to the technical features of the magnification system. CONCLUSION: The students had positive perspectives on the use of magnification in their dentistry training program, including improvements in posture, hand skills and procedure quality.

Implementing magnification during pre-clinical training: Effects on procedure quality and working posture.

OBJECTIVE: The objective of this study was to evaluate the effects of magnification on the quality of two pre-clinical procedures, class I cavity preparations and composite resin restorations, and to evaluate the working posture. METHODS: This was an experimental laboratory study. The response variables were the quality of cavity preparations and Class I restorations as well as the working posture adopted during the execution of these procedures. The independent variables were the magnification system under four levels (unaided visualisation, the use of a simple loupe, the use of a Galilean loupe and the use of a Keplerian loupe) and the artificial teeth treated. Class I cavity preparations and restorations (N = 320) were performed using standardised procedures, and the quality achieved was evaluated using pre-established criteria. Working posture was recorded using digital video cameras and was evaluated using the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). A two-factor analysis of variance (ANOVA) and multiple comparison test were performed (α = 0.05). RESULTS: The quality of cavity preparation did not differ significantly amongst the different magnification systems (P = 0.082). Galilean and Keplerian systems had a positive impact on restoration quality only for the left mandibular first molar (P = 0.04). Higher posture scores were observed when Galilean and Keplerian loupes (P = 0.01) were used, regardless of the tooth being treated. CONCLUSION: The use of Galilean and Keplerian magnification lenses did not affect the quality of the pre-clinical procedures performed whilst improved the scores of ergonomic posture.

Preclinical dental training: Association between difficulty in performing restorative procedures and the adoption of ergonomic posture.

OBJECTIVE: The aim of this study was to determine any correlations between difficulty in performing restorative procedures and the adoption of ergonomic posture by dental students in a preclinical course. METHODS: The sample was composed of second-year undergraduate students enrolled in the School of Dentistry of São Paulo State University (UNESP), Araraquara (n = 56). The data were collected from weekly records in which students who had participated in training in a preclinical restorative dentistry laboratory registered the difficulty they experienced performing given proposed preclinical procedures and adopting ergonomic posture (positioning of students' legs, thighs, spine, arms, and forearms, as well as the positioning of both the dental light and the dental mannequin's head, the distance between the operating field and the operator's eyes, and the location of the instruments used in the procedures). Answers were provided on a scale of zero to ten points (zero = no difficulty; 10 = maximum difficulty). A descriptive statistical analysis was performed. The correlation between the level of difficulty in performing the restorative procedures and in the adoption of ergonomic posture was estimated using the Pearson correlation coefficient (r), and its significance was tested using Student's t test. To evaluate the effect of time on students' perceived difficulties in implementing ergonomic posture, the first 2 weeks of training was defined as the initial time, whilst the last 2 weeks was defined as final time (scores from these periods were averaged). After the normality assumptions were verified, Student's t test for paired samples was performed. The significance level adopted was <5%. RESULTS: A correlation was found between the difficulty students experienced performing the preclinical procedures and their difficulties implementing ergonomic posture; the correlation was significant, though the correlation ranged from slight to moderate (P < 0.001; r = 0.38-0.63). In addition, the data also showed that the students' perceptions of how difficult it was to implement these posture items decreased significantly over time (P < 0.001). CONCLUSION: The correlation between perceived difficulty in performing the preclinical restorative dentistry procedures and the application of ergonomic posture was slight to moderate, and the students' perceived difficulties in maintaining ergonomic posture decreased over the course of the school year.

Work-related activities that may contribute to musculoskeletal symptoms among dental students: validation study.

BACKGROUND: Dentists are exposed to occupational hazards, such as musculoskeletal disorders, in which symptoms can manifest early in clinical practice. OBJECTIVES: To estimate the reliability and validity of the Portuguese version of the "Questionnaire on work-related activities that may contribute to musculoskeletal symptoms" when applied to dental students. METHODS: 553 Brazilian students participated in the study. The one-factor structure originally proposed was tested through confirmatory factor analysis (CFA) using the indexes c2/df, CFI, GFI, and RMSEA. After observing an inadequate good fit (c2/df=7.140, CFI=0.791, GFI=0.778, RMSEA=0.129), the sample was subdivided into 3 groups and an exploratory factor analysis was conducted (EFA) (n=255). A CFA was then conducted using a subsample (n=113). To test the invariance of the obtained factorial solution, a multi-group analysis was performed using a third sample, independent from the others (n=185). The convergent (AVE) and discriminant (r2) validity were assessed. The composite reliability (CR), Cronbach's alpha coefficient (a), and intra-class correlation coefficient (r) were calculated. RESULTS: In the EFA, 3 factors were extracted: "Repetitiveness," "Working posture," and "External factors" (c2=21895.154; p<0.001; KMO=0.905; l1=6.683; l2=1.464; l3=1.277) that explained 62.82% of the total variance. The three-factor model presented an adequate good fit (n=113 and n=185) (c2/df=2.259; CFI=0.885; GFI=0.833; RMSEA=0.066). The convergent validity was compromised only for "Repetitiveness" (AVE=0.412-0.653). The discriminant validity (r2=0.333-0.428), composite reliability, internal consistency, and reproducibility were adequate for all factors (CR=0.736-0.883; a=0.747-0.876; r=0.729-0.940). CONCLUSION: The questionnaire proved to be reliable and valid for the sample of dentistry students if the three-factor model is used.

Effects of immersion media and repolishing on color stability and superficial morphology of nanofilled composite resin.

This study evaluated the influence of fluoride mouth rinses and repolishing on the superficial morphology and color stability of nanofilled resin. About 150 specimens were prepared and polished using aluminum oxide discs for 15 s with a pressure of 2 kg. The experimental groups were divided according to the immersion medium (artificial saliva, 0.5% sodium fluoride, Fluordent Reach, Oral B, Fluorgard) and repolishing procedure (without and with). The specimens were continuously immersed for 1 week. Thereafter, half of each sample was repolished. A color reading was performed after 24 h of immersion in the artificial saliva baseline, after continuous immersion, and after repolishing. The superficial morphology was examined using scanning electron microscopy (SEM) in a qualitative way. Color change (∆E) data were submitted to a mixed analysis of variance using a Shapiro-Wilk test (p>0.05 for the different immersion media) and Sidak's test (p<0.05 for the differences between groups). In the interaction between the repolishing and the immersion media, Fluorgard showed a statistical difference between the ∆E values with and without repolishing (p<0.0001). On the SEM observations, both Fluordent Reach and Fluorgard caused degradation of the superficial resinous matrix of the composite after continuous immersion. This matrix was removed after repolishing.

The effect of Galilean magnification loupes on the visual acuity and working distance of dental students.

OBJECTIVE: This study aimed to evaluate the visual acuity and working distance of dental students using Galilean loupes at different magnification levels. METHODS: The participants included 50 undergraduate dentistry students selected from each class in the second to fifth years (N = 200) of São Paulo State University, School of Dentistry, Araraquara. The response variables were (i) the working distance between the operator's eyes and the mouth of the dental phantom head, and (ii) visual acuity. The independent variables were the five levels of the Galilean magnification system (naked eye, Galilean loupe simulator without magnification, and Galilean loupes with 2.5×, 3.0×, or 3.5× magnification) and academic year. Visual acuity was measured using a miniature Snellen eye chart inserted into the Class I cavities of the maxillary molars. After verifying the assumptions of normality and sphericity, a mixed repeated measures analysis was performed (α = 0.05). RESULTS: Statistical significance was found between the "magnification system" and "academic year" for visual acuity (p < 0.001). For the second-, fourth-, and fifth-year participants, there were no significant differences in visual acuity between the naked eye and different magnifications of the Galilean loupes, which were superior to and significantly different from that of the loupe simulator. For the working distance, statistical significance was observed in the interaction between "magnification system" and "academic year" (p = 0.008). For the third-, fourth-, and fifth-year participants, there was no significant difference in the working distance between the naked eye and different magnifications of the Galilean loupes, which were superior to and significantly different from that of the simulator. CONCLUSION: It was concluded that the different magnification levels of the Galilean loupes did not influence the visual acuity or distance between the eyes of the operator and the mouth of the dental phantom head in the evaluated students.

Magnification in preclinical procedures: effect on muscle activity and angular deviations of the neck and trunk.

Objectives: This study aimed to assess the effects of different magnification systems on the angular deviations of the neck and trunk and the muscle activities of the upper back and neck during preclinical cavity preparation. Methods: This was an experimental laboratory study, with the angular deviations from the neutral positions of the neck and trunk and the activities of the bilateral upper back (the descending and ascending trapezius) and neck (sternocleidomastoid) muscles as the dependent variables. The independent variables were the different magnification systems used (Simple, Galilean, and Keplerian loupes, with direct vision as the control) and prepared teeth (teeth 16, 26, 36, and 46). A dental mannequin phantom head with artificial resin teeth was used, and Class I cavity preparations for composite resin were performed on teeth 16, 26, 36, and 46 using a 1012 round diamond bur at low speed. To analyze the angular deviations, the postures adopted during the procedure were recorded using a tripod-mounted camera positioned to provide a lateral view of the operator. A trained researcher measured the angular deviations using the software entitled "Software for Postural Assessment"-SAPO (version 0.69). Bilateral muscle activity was assessed using surface electromyography. Descriptive statistical analysis was performed, and after verifying the assumptions of normality and homoscedasticity, two-way analysis of variance and the Tukey and Games-Howell post-hoc tests were used to compare the data (α=0.05). Results: The angular deviation from the neutral position of the neck was found to be significantly higher during cavity preparations performed with the naked eye and the Simple loupe, irrespective of the prepared tooth. With regard to tooth location, the angular deviation of the neck was significantly greater during cavity preparation on teeth 16 and 26, and the angular deviation of the trunk was significantly greater during cavity preparation on tooth 26, regardless of the magnification system used. There were significant differences in right sternocleidomastoid muscle activity between the Simple, Galilean, and Keplerian loupes, with activity being the lowest for the Galilean loupe (p = 0.008). There were no significant differences in left sternocleidomastoid muscle activity between the loupes, regardless of the prepared tooth (p = 0.077). The activities of the bilateral descending trapezius and the right ascending trapezius muscles were significantly lower when the Galilean loupe was used (p < 0.010). Conclusion: These results suggest that the Galilean loupe resulted in lower muscle activity in the neck and back regions and that the Galilean and Keplerian loupes resulted in less angular deviations of the neck and trunk during cavity preparation.

Silver-enriched microdomain patterns as advanced bactericidal coatings for polymer-based medical devices.

Today, it would be difficult for us to live a full life without polymers, especially in medicine, where its applicability is constantly expanding, giving satisfactory results without any harm effects on health. This study focused on the formation of hexagonal domains doped with AgNPs using a KrF excimer laser (λ=248 nm) on the polyetheretherketone (PEEK) surface that acts as an unfailing source of the antibacterial agent - silver. The hexagonal structure was formed with a grid placed in front of the incident laser beam. Surfaces with immobilized silver nanoparticles (AgNPs) were observed by AFM and SEM. Changes in surface chemistry were studied by XPS. To determine the concentration of released Ag+ ions, ICP-MS analysis was used. The antibacterial tests proved the antibacterial efficacy of Ag-doped PEEK composites against Escherichia coli and Staphylococcus aureus as the most common pathogens. Because AgNPs are also known for their strong toxicity, we also included cytotoxicity tests in this study. The findings presented here contribute to the advancement of materials design in the biomedical field, offering a novel starting point for combating bacterial infections through the innovative integration of AgNPs into inert synthetic polymers.

Correction: University engagement of dental students related to educational environment: A transnational study.

[This corrects the article DOI: 10.1371/journal.pone.0259524.].

Enhanced Wnt/ß-catenin signalling during tooth morphogenesis impedes cell differentiation and leads to alterations in the structure and mineralisation of the adult tooth.

BACKGROUND INFORMATION: Previous studies have indicated that over-activation of the wingless interaction site (Wnt)/ß-catenin signalling pathway has important implications for tooth development, at the level of cell differentiation and morphology, as well as for the production of supernumerary teeth. Here, we provide evidence for a crucial role of this signalling pathway during the stage of tooth morphogenesis. We have developed an in vitro model consisting of 14.5-day-old mouse embryo first molars, in which the Wnt pathway is overactivated by the glycogen synthase kinase-3 inhibitor 6-bromoindirubin-3'-oxime (BIO; 20 µM). RESULTS: We found that over-activation of the Wnt/ß-catenin pathway delayed the differentiation and growth of the inner dental epithelium. In addition, in contrast to controls in which Nestin protein expression was restricted to differentiated odontoblasts, in BIO-treated molars, Nestin expression spread through sub-odontoblastic cellular layers. This alteration appears to be related to: (i) the over-expression of Bmp4 in the same region, (ii) the delay in odontoblast precursor cell differentiation and (iii) increased proliferation of mesenchymal cells. Furthermore, treatments longer than 6 days induced the malformation of typical dental structures and led to a total lack of cell differentiation. Finally, over-activation of the Wnt route during odontogenesis resulted in adult teeth which presented altered size, morphology and mineralisation. CONCLUSIONS: Our results indicate that Wnt/ß-catenin over-activation during tooth morphogenesis is sufficient to cause dramatic alterations in the adult tooth, by delaying cellular differentiation and stimulating proliferation of the dental mesenchyme of developing teeth.

Abnormal fixation in individuals with age-related macular degeneration when viewing an image of a face.

PURPOSE: It has been reported that patients with macular disease have difficulties with face perception. Some of this difficulty may be caused by the sensory and perceptual consequences of using peripheral retina. However, strong correlations have not always been found between performance on face tasks and clinical measure of function. Based on the evidence of abnormal eye movements by patients with age-related macular degeneration (AMD), we explored whether abnormal fixation patterns occur when these patients view an image of a face. METHODS: An OPKO OCT/SLO was used to collect structural and functional data. For each subject, the structural location of disease was determined, and the locus and stability of fixation were quantified. A SLO movie of fundus movements was recorded while the subject viewed an image of a face. RESULTS: The number of fixations on internal (eyes, nose, and mouth) and external features were measured. A two-way repeated-measures analysis of variance found significant differences between the control and patient groups and among locations. A significant interaction between group and location was also found. Post hoc comparisons found a significantly greater proportion of fixations on external features for the AMD group than that in the control group. CONCLUSIONS: The observed patterns of fixations of our subjects with AMD were similar to those observed in other groups of patients who have difficulties with face perception. For example, individuals with social phobias, Williams syndrome, autism, schizophrenia, or prosopagnosia have altered face perceptions and also have a significantly greater proportion of fixations on external features of faces. Abnormal eye movement patterns and fixations may contribute to deficits in face perception in AMD patients.

Working postures of dental students: ergonomic analysis using the Ovako Working Analysis System and rapid upper limb assessment.

BACKGROUND: As dentistry is a profession that demands a manipulative precision of hand movements, musculoskeletal disorders are among the most common occupational diseases. OBJECTIVES: This study estimated the risk of musculoskeletal disorders developing in dental students using the Ovako Working Analysis System (OWAS) and Rapid Upper Limb Assessment (RULA) methods, and estimated the diagnostic agreement between the 2 methods. METHODS: Students (n = 75), enrolled in the final undergraduate year at the Araraquara School of Dentistry--UNESP--were studied. Photographs were taken of students while performing diverse clinical procedures (n = 283) using a digital camera, which were assessed using OWAS and RULA. A risk score was attributed following each procedure performed by the student. The prevalence of the risk of musculoskeletal disorders was estimated per point and for a 95% CI. To assess the agreement between the 2 methods, Kappa statistics with linear weighting were used. The level of significance adopted was 5%. RESULTS: There was a high prevalence of the mean score for risk of musculoskeletal disorders in the dental students evaluated according to the OWAS method (p = 97.88%; 95% CI: 96.20-99.56%), and a high prevalence of the high score (p = 40.6; 95% CI: 34.9-46.4%) and extremely high risk (p = 59.4%; 95% CI: 53.6-65.1%) according to RULA method Null agreement was verified (k = 0) in the risk di agnosis of the tested methods. CONCLUSION: The risk of musculoskeletal disorders in dental students estimated by the OWAS method was medium, whereas the same risk by the RULA method was extremely high. There was no diagnostic agreement between the OWAS and RULA methods.