Neuron-specific enolase at admission as a predictor for stroke volume, severity and outcome in ischemic stroke patients: a prognostic biomarker review.

An ideal blood biomarker for stroke should provide reliable results, enable fast diagnosis, and be readily accessible for practical use. Neuron-specific enolase (NSE), an enzyme released after neuronal damage, has been studied as a marker for brain injury, including cerebral infarction. However, different methodologies and limited sample sizes have restricted the applicability of any potential findings. This work aims to determine whether NSE levels at Emergency Department (ED) admission correlate with stroke severity, infarcted brain volume, functional outcome, and/or death rates. A systematic literature review was performed using PubMed, Embase, and Scopus databases. Each reviewer independently assessed all published studies identified as potentially relevant. All relevant original observational studies (cohort, case-control, and cross-sectional studies) were included. Eleven studies (1398 patients) met the inclusion criteria. Among these, six studies reported a significant correlation between NSE levels and stroke severity, while only one found no association. Four studies indicated a positive relationship between infarcted brain volume assessed by imaging and NSE levels, in contrast to the findings of only one study. Four studies identified an association related to functional outcome and death rates, while three others did not reach statistical significance in their findings. These data highlight that NSE levels at ED admissions proved to be a promising tool for predicting the outcome of ischemic stroke patients in most studies. However, they presented high discrepancies and low robustness. Therefore, further research is necessary to establish and define the role of NSE in clinical practice.

Development of a low-cost congenital abdominal wall defect simulator (wall-go) for undergraduate medical education: a validation study.

BACKGROUND: Congenital Anomalies were responsible for 303,000 deaths in the neonatal period, according to the WHO, they are among the world's top 20 causes of morbidity and mortality. Expensive simulators demonstrate several diseases, but few are related to congenital anomalies. This study aims to develop, validate, and evaluate low-cost simulator models (WALL-GO) of the most common abdominal wall defects, gastroschisis, and omphalocele, to enable diagnosis through an accessible tool with study value and amenable to replication. METHODS: Market research was conducted to find materials to build low-cost models. The researchers built the model and underwent validation assessment of the selected experts who scored five or more in the adapted Fehring criteria. The experts were assessed through a 5-point Likert scale to 7 statements (S1-7). Statements were assigned values according to relevance in face and transfer validities. Concomitantly, the model was also evaluated by students from 1st to 5th year with the same instruments. Content Validity Indexes (CVIs) were considered validated between groups with concordance greater than 90%. Text feedback was also collected. Each statement was subjected to Fisher's Exact Test. RESULTS: Gastroschisis and omphalocele model costs were US $15 and US $27, respectively. In total, there were 105 simulator evaluators. 15 experts were selected. Of the 90 students, there were 16 (1st year), 22 (2nd), 16 (3rd), 22 (4th), and 14 (5th). Students and experts obtained CVI = 96.4% and 94.6%, respectively. The CVIs of each statement were not significantly different between groups (p < 0,05). CONCLUSIONS: The WALL-GO models are suitable for use and replicable at a manufacturable low cost. Mannequins with abdominal wall defects are helpful in learning to diagnose and can be applied in teaching and training health professionals in developing and low-income countries.

The Multifarious Functions of Leukotrienes in Bone Metabolism.

Leukotrienes (LTs) are derived from arachidonic acid metabolism by the 5-lipoxygenase (5-LO) enzyme. The production of LTs is stimulated in the pathogenesis of rheumatoid arthritis (RA), osteoarthritis, and periodontitis, with a relevant contribution to bone resorption. However, its role in bone turnover, particularly the suppression of bone formation by modulating the function of osteoclasts and osteoblasts, remains unclear. We investigated the effects of LTs on bone metabolism and their impact on osteogenic differentiation and osteoclastogenesis using a 5-LO knockout (KO) mouse model. Results from micro-computed tomography (µCT) analysis of femur from 8-week-old 5-LO-deficient mice showed increased cortical bone and medullary region in females and males and decreased trabecular bone in females. In the vertebra, we observed increased marrow area in both females and males 5-LO KO and decreased trabecular bone only in females 5-LO KO. Immunohistochemistry (IHC) analysis showed higher levels of osteogenic markers tissue-nonspecific alkaline phosphatase (TNAP) and osteopontin (OPN) and lower expression of osteoclastogenic marker tartrate-resistant acid phosphatase (TRAP) in the femurs of 5-LO KO mice versus wild-type (WT). Alkaline phosphatase activity and mineralization assay results showed that the 5-LO absence enhances osteoblasts differentiation and mineralization but decreases the proliferation. Alkaline phosphatase (ALP), Bglap, and Sp7 gene expression were higher in 5-LO KO osteoblasts compared to WT cells. Eicosanoids production was higher in 5-LO KO osteoblasts except for thromboxane 2, which was lower in 5-LO-deficient mice. Proteomic analysis identified the downregulation of proteins related to adenosine triphosphate (ATP) metabolism in 5-LO KO osteoblasts, and the upregulation of transcription factors such as the adaptor-related protein complex 1 (AP-1 complex) in long bones from 5-LO KO mice leading to an increased bone formation pattern in 5-LO-deficient mice. We observed enormous differences in the morphology and function of osteoclasts with reduced bone resorption markers and impaired osteoclasts in 5-LO KO compared to WT osteoclasts. Altogether, these results demonstrate that the absence of 5-LO is related to the greater osteogenic profile. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Ionic liquids as protein stabilizers for biological and biomedical applications: A review.

Biotechnology has revolutionized science and health care by providing new biomolecules with biological and medical applications. However, the low stability of several life-saving bioproducts still hinders their transport, storage, and application. Hence, protein-based bioproducts instability and high costs are the main bottlenecks limiting access to biopharmaceuticals in low-income countries and communities. Aiming to improve the stability of protein-based products, researchers have studied ionic liquids (ILs) as protein stabilizers due to their unique properties and ability to enhance the solubility and stability of a wide range of biomolecules. Although different classes of ILs have the potential to improve protein stability, their effects are dependent on several variables, such as the complex and intrinsic properties of proteins, the nature and concentration of ILs, and environmental conditions (e.g., temperature, pH). For medical applications, the biocompatibility of ILs can also limit their biological use. Therefore, the current state-of-the-art on ILs applications for non-enzymatic protein stabilization was carefully analyzed and discussed, considering protein properties, ILs classes, and IL solutions concentrations. Lastly, a critical perspective regarding ILs applications as protein stabilizers was presented, highlighting the current lacunas in the field while guiding future studies to answer the existing paradigms.

Effect of sodium hexametaphosphate and quercetin, associated or not with fluoride, on dentin erosion in vitro.

OBJECTIVE: to investigate the ability of solutions containing sodium hexametaphosphate, fluoride and quercetin, alone or in association, to prevent dentin erosion and to inhibit matrix metalloproteinases -2 and -9 activity using in vitro protocols. DESIGN: Root dentin blocks (n = 96) were prepared and divided into 8 experimental groups (n = 12/group), according to the solutions to be tested: Placebo; 0.24% sodium fluoride (F); 1.0% sodium hexametaphosphate (HMP); 0.03% quercetin (QC); F+HMP; F+QC; HMP+QC; and F+HMP+QC. Erosive challenges were performed 4×/day for 5 days. Specimens were treated with the respective solutions for one minute, twice a day. Next, dentin loss (profilometry) and integrated hardness area in depth (KHN × µm) were determined. The antiproteolytic potential was assessed by gelatin zymography. Dentin erosion results (log10-transformed) were submitted to one-way ANOVA, followed by Tukey's test. Integrated hardness area in depth data (raw) were submitted to two-way, repeated-measures ANOVA, followed by Holm-Sidak's test (p<0.05). RESULTS: Dentin erosion was significantly lower for F+HMP+QC than for all other treatments. At the shallowest depths (5-30 µm), blocks treated with F+HMP+QC had the highest integrated hardness area in depth values. All treatments completely inhibited matrix metalloproteinases-2 activity, except for the group QC (77% inhibition). For matrix metalloproteinases-9, all HMP-containing solutions or F+QC promoted total antiproteolytic activity. CONCLUSION: The association of fluoride, sodium hexametaphosphate, and quercetin must be considered a valuable strategy for novel product formulation for home and professional use, considering its superior protective effects against dentin erosion and its antiproteolytic potential.

Evaluating the potential of Pediococcus pentosaceus as a biocontrol agent against tenuazonic acid-producing Alternaria alternata on livestock feeds.

AIMS: This study aims to demonstrate the potential of the lactic acid bacteria (LAB) Pediococcus pentosaceus LBM18 against the mycotoxin-producing Alternaria alternata TEF-1A and highlight its application as an effective grain silage inoculant to control mycotoxin contamination. METHODS AND RESULTS: The antifungal properties of Ped. pentosaceus lyophilized (PPL) were assessed by evaluating its effect on A. alternata TEF-1A grown in a corn silage-based medium, which included morphological changes by Scanning Electron Microscopy (SEM) observations, growth rate, conidia production assays, and inhibition of Tenuazonic acid (TeA) production by high-performance liquid chromatography (HPLC-MS/MS) analyses. Furthermore, TeA biosynthesis was monitored for changes at the molecular level by PKS gene expression. The growth and sporulation processes of A. alternata TEF-1A were affected by Ped. pentosaceus LBM18 in a concentration-dependent manner. Moreover, a significant inhibition of TeA production (74.3%) and the transcription level of the PKS gene (42.9%) was observed. CONCLUSIONS: Ped. pentosaceus is one of the promising LAB to be applied as an inoculant for corn silage preservation, aiming to inhibit mycotoxigenic fungi growth and their mycotoxin production. SIGNIFICANCE AND IMPACT OF THE STUDY: Ped. pentosaceus could be used as an inoculant to reduce fungal and mycotoxins contamination in grain silage production.

Bacteriocinogenic probiotic bacteria isolated from an aquatic environment inhibit the growth of food and fish pathogens.

The conditions of aquatic environments have a great influence on the microbiota of several animals, many of which are a potential source of microorganisms of biotechnological interest. In this study, bacterial strains isolated from aquatic environments were bioprospected to determine their probiotic profile and antimicrobial effect against fish and food pathogens. Two isolates, identified via 16S rRNA sequencing as Lactococcus lactis (L1 and L2) and one as Enterococcus faecium 135 (EF), produced a bacteriocin-like antimicrobial substance (BLIS), active against Listeria monocytogenes, Salmonella Choleraesuis and Salmonella Typhimurium. Antimicrobial activity of BLIS was reduced when exposed to high temperatures and proteolytic enzymes (trypsin, pepsin, papain and pancreatin). All strains were sensitive to 7 types of antibiotics (vancomycin, clindamycin, streptomycin, gentamicin, chloramphenicol, rifampicin and ampicillin), exhibited a high rate of adherence to Caco-2 cells and expressed no hemolysin and gelatinase virulence factors. EF showed some resistance at pH 2.5 and 3.0, and L2/EF showed higher resistance to the action of bile salts. Finally, the presence of bacteriocin genes encoding for proteins, including Nisin (L1 and L2), Enterocin A, B, P, and Mundticin KS (EF) was detected. The molecular and physiological evidence suggests that the bacterial isolates in this study could be used as natural antimicrobial agents and may be considered safe for probiotic application.

Osteoblastic response to biomaterials surfaces: Extracellular matrix proteomic analysis.

The cellular response to surfaces is mediated, among other factors, by the extracellular matrix (ECM). However, little is known about the ECM proteome during mineralization. Our objective was to compare the ECM composition formed by osteoblast on different materials surfaces with proteomic analysis. Three types of biomaterial surfaces (pure titanium, anodized titanium, and zirconia) were used. Osteoblasts (MC3T3 linage) cells were cultivated on the biomaterials for 7, 14, and 21 days with the osteogenic medium. For the proteomic analysis, the specimens were washed, decellularized, and the ECM was collected. The majority of the typical ECM proteins, out of a total of 24 proteins identified, was expressed and regulated equally on the three biomaterials tested. Alpha-1,4 glucan phosphorylase was found to be down-regulated on zirconia on the seventh day, while at the same time, glycogen phosphorylase brain form was up-regulated on anodized titanium, both when compared with pure titanium (ratio: 1.06 and 0.97, respectively). And after 14 days of culture, glycogen phosphorylase brain form was downregulated on zirconia when compared with pure titanium (ratio: 0.90), suggesting the influence of material surface roughness and chemical composition on energy metabolism. Proteins related to bone development like Transforming growth factor beta-3 and Fibroblast growth factor 8 were found exclusively on pure titanium on the 21st day. Altogether, our results show a possible influence of material surfaces on the composition of ECM.

Beneficial effects of a mouthwash containing an antiviral phthalocyanine derivative on the length of hospital stay for COVID-19: randomised trial.

The risk of contamination and dissemination by SARS-CoV-2 has a strong link with nasal, oral and pharyngeal cavities. Recently, our research group observed the promising performance of an anionic phthalocyanine derivative (APD) used in a mouthwash protocol without photoexcitation; this protocol improved the general clinical condition of patients infected with SARS-CoV-2. The present two-arm study evaluated in vitro the antiviral activity and cytotoxicity of APD. Additionally, a triple-blind randomized controlled trial was conducted with 41 hospitalized patients who tested positive for COVID-19. All the included patients received World Health Organization standard care hospital treatment (non-intensive care) plus active mouthwash (experimental group AM/n = 20) or nonactive mouthwash (control group NAM/n = 21). The adjunct mouthwash intervention protocol used in both groups consisted one-minute gargling/rinsing / 5 times/day until hospital discharge. Groups were compared considering age, number of comorbidities, duration of symptoms prior admission and length of hospital stay (LOS). The associations between group and sex, age range, presence of comorbidities, admission to Intensive care unit (ICU) and death were also evaluated. The in vitro evaluation demonstrated that APD compound was highly effective for reduction of SARS-CoV-2 viral load in the 1.0 mg/mL (99.96%) to 0.125 mg/mL (92.65%) range without causing cytotoxicity. Regarding the clinical trial, the median LOS of the AM group was significantly shortened (4 days) compared with that of the NAM group (7 days) (p = 0.0314). Additionally, gargling/rinsing with APD was very helpful in reducing the severity of symptoms (no ICU care was needed) compared to not gargling/rinsing with APD (28.6% of the patients in the NAM group needed ICU care, and 50% of this ICU subgroup passed way, p = 0.0207). This study indicated that the mechanical action of the protocol involving mouthwash containing a compound with antiviral effects against SARS-CoV-2 may reduce the symptoms of the patients and the spread of infection. The use of APD in a mouthwash as an adjuvant the hospital COVID-19 treatment presented no contraindication and reduced the hospital stay period.Trial registration: The clinical study was registered at REBEC-Brazilian Clinical Trial Register (RBR-58ftdj).

Surface roughness of titanium disks influences the adhesion, proliferation and differentiation of osteogenic properties derived from human.

PURPOSE: The aim of this study was to investigate the response of osteogenic cell lineage and gingival fibroblastic cells to different surface treatments of grade IV commercially pure Titanium (cpTi) disks. MATERIAL AND METHODS: Grade IV cpTi disks with different surfaces were produced: machined (M), sandblasting (B), sandblasting and acid subtraction (NP), and hydrophilic treatment (ACQ). Surface microtopography characteristics and chemical composition were investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Adhesion and proliferation of SC-EHAD (human surgically-created early healing alveolar defects) and HGF-1 (human gingival fibroblasts) on Ti disks were investigated at 24 and 48 h, and osteogenic differentiation and mineralization were evaluated by assessing alkaline phosphatase (ALP) activity and alizarin red staining, respectively. RESULTS: No significant differences were found among the various surface treatments for all surface roughness parameters, except for skewness of the assessed profile (Rsk) favoring M (p = 0.035 ANOVA). M disks showed a slightly higher (p > 0.05; Kruskal-Wallis/Dunn) adhesion of HGF-1 (89.43 ± 9.13%) than SC-EHAD cells (57.11 ± 17.72%). ACQ showed a significantly higher percentage of SC-EHAD (100%) than HGF-1 (69.67 ± 13.97%) cells adhered at 24 h. SC-EHAD cells expressed increased ALP activity in osteogenic medium at M (213%) and NP (235.04%) surfaces, but higher mineralization activity on ACQ (54.94 ± 4.80%) at 14 days. CONCLUSION: These findings suggest that surface treatment influences the chemical composition and the adhesion and differentiation of osteogenic cells in vitro. CLINICAL RELEVANCE: Hydrophilic surface treatment of grade IV cpTi disks influences osteogenic cell adhesion and differentiation, which might enhance osseointegration.

Effect of association of non-steroidal anti-inflammatory and antibiotic agents with calcium hydroxide pastes on their cytotoxicity and biocompatibility.

OBJECTIVES: Evaluate the cytotoxicity and biocompatibility of calcium hydroxide paste [Ca (OH)2] associated with 5% diclofenac sodium, ibuprofen, or amoxicillin. MATERIALS AND METHODS: Pre-osteoblast-like cells were cultivated and the MTT test was used to determine the cytotoxicity of the paste extracts after time intervals of 24, 48, 72 h, and 7 days. Tubes containing Ca (OH)2 pastes associated with the drugs and empty tubes were implanted in subcutaneous tissue of 30 rats. After 7 and 30 days, the specimens were removed and submitted to histological analysis. The data obtained were submitted to Kruskal-Wallis and Dunn tests (p ≤ 0.05). RESULTS: All the Ca (OH)2 pastes promoted cell viability after all periods. At 7 days, there was greater inflammatory tissue reaction adjacent to the implants. At 30 days, there was a significant reduction in the number of inflammatory cells, and increase in fibroblasts in all groups. In this period, a lower number of inflammatory cells and a higher number of fibroblasts were observed in the capsules adjacent to the association with diclofenac, when compared with the other mixtures (p ≤ 0.05); the capsule thickness was greater at 7 days than at 30 days. CONCLUSIONS: The Ca (OH)2 pastes associated with the drugs were not cytotoxic and presented biocompatibility after implantation in rat subcutaneous tissues. CLINICAL RELEVANCE: Ca (OH)2 pastes with anti-inflammatory or antibiotic may be clinical alternatives as intracanal medication to reduce resistant microorganisms in root canal system.

In vitro and in vivo assessment of CaP materials for bone regenerative therapy. The role of multinucleated giant cells/osteoclasts in bone regeneration.

In this work, bone formation/remodeling/maturation was correlated with the presence of multinucleated giant cells (MGCs)/osteoclasts (tartrate-resistant acid phosphatase [TRAP]-positive cells) on the surface of beta-tricalcium phosphate (ß-TCP), sintered deproteinized bovine bone (sDBB), and carbonated deproteinized bovine bone (cDBB) using a maxillary sinus augmentation (MSA) in a New Zealand rabbit model. Microtomographic, histomorphometric, and immunolabeling for TRAP-cells analyses were made at 15, 30, and 60 days after surgery. In all treatments, a faster bone formation/remodeling/maturation and TRAP-positive cells activity occurred in the osteotomy region of the MSA than in the middle and submucosa regions. In the ß-TCP, the granules were rapidly reabsorbed by TRAP-positive cells and replaced by bone tissue. ß-TCP enabled quick bone regeneration/remodeling and full bone and marrow restoration until 60 days, but with a significant reduction in MSA volume. In cDBB and sDBB, the quantity of TRAP-positive cells was smaller than in ß-TCP, and these cells were associated with granule surface preparation for osteoblast-mediated bone formation. After 30 days, more than 80% of granule surfaces were surrounded and integrated by bone tissue without signs of degradation, preserving the MSA volume. Overall, the materials tested in a standardized preclinical model led to different bone formation/remodeling/maturation within the same repair process influenced by different microenvironments and MGCs/osteoclasts. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:282-297, 2020.

TiF4 and NaF varnishes induce low levels of apoptosis in murine and human fibroblasts through mitochondrial Bcl-2 family and death receptor signalling.

OBJECTIVES: This study evaluated the level and mechanism of apoptosis in human gingival fibroblasts (HGF) and murine fibroblasts (NIH/3T3) treated with a titanium tetrafluoride (TiF4) varnish compared those treated with a sodium fluoride (NaF) varnish. METHODS: Cells were treated with a TiF4, NaF (both 2.45%F) or placebo varnish for 6 h and were then examined using the TUNEL method. The activities of caspase-3, -8 and -9 were assessed. cDNA for Bax, Bad, Bcl-2 and Fas-L was amplified by quantitative PCR. Bax, Bcl-2 and Fas-L were further detected by western blot analysis. RESULTS: Both fluorides similarly increased the percentage of apoptosis, while they failed to activate caspases. The Bax/Bcl-2 gene expression ratio was not altered by either fluoride treatment regardless of the type of cell. NaF varnish increased the amplification of the Fas-L gene in NIH/3T3 and HGF cells, while treatment with the TiF4 varnish resulted in a lower Bad/Bcl-2 expression ratio compared to that of the control for NIH/3T3 cells, but not for HGF cells. No effect of the fluorides was detected in the protein analysis. CONCLUSIONS: NaF and TiF4, at the studied conditions, similarly induce a low level of apoptosis, with consequent modest activation of the Bcl-2 and Fas-l-dependent signalling pathways. Generally, HGF cells are more susceptible to the fluoride effect than NIH/3T3 cells.

Hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on Streptococcus mutans biofilm and tooth demineralization.

OBJECTIVES: This study evaluated the effect of the hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves (alone or combined) on the viability of Streptococcus mutans biofilm and on the prevention of enamel demineralization. METHODS: Strain of S. mutans (ATCC 21175) was reactivated in BHI broth. Minimum inhibitory concentration, minimum bactericidal concentration, minimum inhibition biofilm concentration and minimum eradication biofilm concentration were determined in order to choose the concentrations to be tested under biofilm model. S. mutans biofilm (5 × 105 CFU/ml) was produced on bovine enamel, using McBain saliva under 0.2% sucrose exposure, for 3 days. The biofilm was daily treated with the extracts for 1 min. The biofilm viability was tested by fluorescence and the enamel demineralization was measured using TMR. RESULTS: Myracrodruon urundeuva All. (Isolated or combined) at the concentrationsc ≥0.625 mg/ml was able to reduce bacteria viability, while Qualea Grandflora Mart. alone had antimicrobial effect at 5 mg/ml only (p < 0.05). On the other hand, none of the extracts were able to reduce enamel demineralization. CONCLUSIONS: The hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves (isolated or combined) have antimicrobial action; however, they do not prevent enamel caries under S. mutans biofilm model.

Comparison of the effect of root surface modification with citric acid, EDTA, and aPDT on adhesion and proliferation of human gingival fibroblasts and osteoblasts: an in vitro study.

Root demineralization is used in Periodontics as an adjuvant for mechanical treatment. The aim of this study was to evaluate the effects of root surface modification with mechanic, chemical, and photodynamic treatments on adhesion and proliferation of human gingival fibroblasts and osteoblasts. Root fragments were treated by scaling and root planing (C-control group), EDTA (pH 7), citric acid plus tetracycline (CA-pH 1), and antimicrobial photodynamic therapy (aPDT) with toluidine blue O and red laser (pH 4). Cells were seeded (104 cells/well, 6th passage) on root fragments of each experimental group and cultured for 24, 48, and 72 h. Cells were counted in scanning electron microscopy images by a calibrated examiner. For fibroblasts, the highest number of cells were present at 72-h period (p < 0.05). EDTA group showed a very low number of cells in relation to CA group (p < 0.05). CA and aPDT group presented higher number of cells in all periods, but without differences between other treatment groups (p > 0.05). For osteoblasts, there was a significant increase in cell numbers for aPDT group at 72 h (p < 0.05). In conclusion, aPDT treatment provided a positive stimulus to osteoblast growth, while for fibroblasts, aPDT and CA had a tendency for higher cell growth.

Low-Level Laser Action on Orthodontically Induced Root Resorption: Histological and Histomorphometric Evaluation.

Introduction: Studies have been conducted to develop a means of preventing, controlling or reducing orthodontically induced root resorption. Phototherapy has demonstrated effectiveness as an anti-inflammatory and, considering the inflammatory origin of this pathology, this study evaluated the effects of laser on root resorption. Methods: The research was conducted among 54 80-day-old male Wistar rats, with weights of 280 ± 40 g. Phototherapy consisted of a diode laser (Ga-Al-As), calibrated with a wavelength of 808 nm, an output power of 100 mW, 2.1 J or 96 J of energy and area of 0.0028 cm2. The application was continuous, punctual and with contact. The left first maxillary molar was moved by a super-elastic closed spring with a pre-calibrated and constant force of 25 g. The specimens were irradiated every 48 hours, totaling three or six times, depending on the group to which they belonged. Euthanasia was made in the 7th or 10th day after the onset of movement. The histological and histomorphometric examination was performed with sections of 6 µm stained with hematoxylin and eosin (H&E). Results: Considering the dosimetry studied, when compared the subgroups with the same time of movement, 7 or 10 days, the low-level laser (LLL) has no statistically significant effect on the root resorption. As expected, differences were found between groups with different time of movement. Conclusion: Based on the result, this dosimetry does not seem to be clinically recommended to avoid or reduce inflammatory root resorption, but it also does not induce any root surface alteration.

Experimental Calcium Silicate-Based Cement with and without Zirconium Oxide Modulates Fibroblasts Viability.

The aim of this study was to verify whether the use of zirconium oxide as a radiopacifier of an experimental calcium silicate-based cement (WPCZO) leads to cytotoxicity. Fibroblasts were treated with different concentrations (10 mg/mL, 1 mg/mL, and 0.1 mg/mL) of the cements diluted in Dulbecco's modified Eagle's medium (DMEM) for periods of 12, 24, and 48 h. Groups tested were white Portland cement (WPC), white Portland cement with zirconium oxide (WPCZO), and white mineral trioxide aggregate Angelus (MTA). Control group cells were not treated. The cytotoxicity was evaluated through mitochondrial-activity (MTT) and cell-density (crystal violet) assays. All cements showed low cytotoxicity. In general, at the concentration of 10 mg/mL there was an increase in viability of those groups treated with WPC and WPCZO when compared to the control group (p<0.05). A similar profile for the absorbance values was noted among the groups: 10 mg/mL presented an increase in viability compared to the control group. On the other hand, smaller concentrations presented a similar or lower viability compared to the control group, in general. A new dental material composed of calcium silicate-based cement with 20% zirconium oxide as the radiopacifier showed low cytotoxicity as a promising material to be exploited for root-end filling.

Differential effects of fluoride during osteoblasts mineralization in C57BL/6J and C3H/HeJ inbred strains of mice.

The behavior of fluoride ions in biological systems has advantages and problems. On one hand, fluoride could be a mitogenic stimulus for osteoblasts. However, high concentrations of this element can cause apoptosis in rat and mouse osteoblasts. Toward an understanding of this effect, we examined the role of sodium fluoride (NaF) in two mouse calvaria osteoblasts during the mineralization process. The animals used were C3H/HeJ (C3) and C57BL/6J (B6) mice. The calvaria cells were cultured for 28 days in the presence of several doses of NaF (0, 5, 10, 25, 50, and 75 µM), and we performed the assays: mineralized nodule measurements, alkaline phosphatase (ALP) activity, determination of type I collagen, and matrix metalloproteinase-2 (MMP-2) activity. The results showed no effects on alkaline phosphatase activity but decreased mineralized nodule formation. In B6 cells, the NaF effect was already seen with 10 µM of NaF and a greater increase of cellular type I collagen, and MMP-2 activity was upregulated after 7 days of NaF exposure. C3 osteoblasts showed a reduction in the mineralization pattern only after 50 µM of NaF with a slight increase of type I collagen and downregulation of MMP-2 activity during the mineralization period. In conclusion, fluoride affects the production and degradation of the extracellular matrix during early onset and probably during the mineralization period. Additionally, the genetic factors may contribute to the variation in cell response to fluoride exposure, and the differences observed between the two strains could be explained by an alteration of the bone matrix metabolism (synthesis and degradation).

Cellular behavior as a dynamic field for exploring bone bioengineering: a closer look at cell-biomaterial interface.

Bone is a highly dynamic and specialized tissue, capable of regenerating itself spontaneously when afflicted by minor injuries. Nevertheless, when major lesions occur, it becomes necessary to use biomaterials, which are not only able to endure the cellular proliferation and migration, but also to substitute the original tissue or integrate itself to it. With the life expectancy growth, regenerative medicine has been gaining constant attention in the reconstructive field of dentistry and orthopedy. Focusing on broadening the therapeutic possibilities for the regeneration of injured organs, the development of biomaterials allied with the applicability of gene therapy and bone bioengineering has been receiving vast attention over the recent years. The progress of cellular and molecular biology techniques gave way to new-guided therapy possibilities. Supported by multidisciplinary activities, tissue engineering combines the interaction of physicists, chemists, biologists, engineers, biotechnologist, dentists and physicians with common goals: the search for materials that could promote and lead cell activity. A well-oriented combining of scaffolds, promoting factors, cells, together with gene therapy advances may open new avenues to bone healing in the near future. In this review, our target was to write a report bringing overall concepts on tissue bioengineering, with a special attention to decisive biological parameters for the development of biomaterials, as well as to discuss known intracellular signal transduction as a new manner to be explored within this field, aiming to predict in vitro the quality of the host cell/material and thus contributing with the development of regenerative medicine.

Effects of fluoride in bone repair: an evaluation of RANKL, OPG and TRAP expression.

The objective of this study was to evaluate comparatively the effect of fluoride in the expression of the receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP) in alveolar bone repair in rats. We used 3 groups of male Wistar rats (n = 5/group), which received drinking water containing different doses of F (NaF): 0, 5 and 50 ppm, for 60 days before the incisors extraction. The upper incisors were extracted and the animals were killed 7, 14, 21 and 30 days after extraction. The hemi-maxillae were collected for microscopic examination (histomorphometric and immunostaining for RANKL, OPG and TRAP). Histomorphometric analysis confirmed an increase in the volume density of neoformed bone between 7 and 30 days for groups control, 5 and 50 ppm of F, with a concomitant decrease in the volume density of connective tissue and blood clot. Higher blood clot for groups 5 and 50 ppm of F at 30 days was observed. The RANKL and OPG expressions were not changed by chronic exposure to fluoride in the drinking water during the studied periods; on the other hand, TRAP expression was changed (at 7 days) by chronic exposure to fluoride (p < 0.05). It was concluded that F in high concentrations can slow the blood clot remission and bone repair, and alter the TRAP expression in the beginning of the bone tissue repair. However, a better understanding about this blood clot remission phenomenon is required.