Menadione and protocatechuic acid: A drug combination with antitumor effects in murine osteosarcoma cells.

Osteosarcoma (OS) is a primary malignant bone tumor that has an abnormal expression of oncogenesis and tumor suppressors and causes dysregulation of various signaling pathways. Thus, novel therapeutic strategies for OS are needed to overcome the resistance of traditional treatments. This study evaluated the cytotoxic and anticancer effects of the association between menadione (MEN) and protocatechuic acid (PCA) in murine OS cells (UMR-106). The concentrations were 3.12 µM of isolated MEN, 500 µM of isolated PCA, and their associations. We performed cell viability assays, morphology modification analysis, cell migration by the wound-healing method, apoptosis by flow cytometry, reactive oxygen species (ROS) production, gene expression of NOX by RT-qPCR, and degradation of MMP-2 and 9 by zymography. Our results showed that the association of MEN+PCA was more effective in OS cells than the compounds alone. The association decreased cell viability, delayed cell migration, and decreased the expression of NOX-2 and ROS. In addition, the MEN+PCA association induced a slight increase in the apoptotic process. In summary, the association can enhance the compound's antitumor effects and establish a higher selectivity for tumor cells, possibly caused by significant mitochondrial damage and antioxidant properties.

Effect of Monocerin, a Fungal Secondary Metabolite, on Endothelial Cells.

This study reports the isolation and identification of the endophytic fungus Exserohilum rostratum through molecular and morphological analysis using optical and transmission electron microscopy (TEM), as well as the procurement of its secondary metabolite monocerin, an isocoumarin derivative. Considering the previously observed biological activities of monocerin, this study was performed on human umbilical vein endothelial cells (HUVECs) that are widely used as an in vitro model for several different purposes. Important parameters, such as cell viability, senescence-associated ß-galactosidase, cellular proliferation by using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE), apoptosis analysis with annexin, cellular morphology through scanning electron microscopy (SEM), and laser confocal analysis were evaluated after exposing the cells to monocerin. After 24 h of exposure to monocerin at 1.25 mM, there was more than 80% of cell viability and a low percentage of cells in the early and late apoptosis and necrosis. Monocerin increased cell proliferation and did not induce cell senescence. Morphological analysis showed cellular integrity. The study demonstrates aspects of the mechanism of action of monocerin on endothelial cell proliferation, suggesting the possibility of its pharmaceutical application, such as in regenerative medicine.

Effect of monocerin, a fungal secondary metabolite, on endothelial cells

This study reports the isolation and identification of the endophytic fungus Exserohilum rostratum through molecular and morphological analysis using optical and transmission electron microscopy (TEM), as well as the procurement of its secondary metabolite monocerin, an isocoumarin derivative. Considering the previously observed biological activities of monocerin, this study was performed on human umbilical vein endothelial cells (HUVECs) that are widely used as an in vitro model for several different purposes. Important parameters, such as cell viability, senescence-associated β-galactosidase, cellular proliferation by using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE), apoptosis analysis with annexin, cellular morphology through scanning electron microscopy (SEM), and laser confocal analysis were evaluated after exposing the cells to monocerin. After 24 h of exposure to monocerin at 1.25 mM, there was more than 80% of cell viability and a low percentage of cells in the early and late apoptosis and necrosis. Monocerin increased cell proliferation and did not induce cell senescence. Morphological analysis showed cellular integrity. The study demonstrates aspects of the mechanism of action of monocerin on endothelial cell proliferation, suggesting the possibility of its pharmaceutical application, such as in regenerative medicine.

Time of clerkship rotations' interruption during COVID-19 and differences on Progress Test's scores.

OBJECTIVES: The transition from face-to-face to remote teaching is yet to be fully understood. In clinical training, traditional teaching must prevail because it is essential for the acquisition of skills and professionalism. However, the responses of each school to the pandemic and the decision on when to resume clerkship rotations were mixed. In this study, we aimed to analyze whether the time to resume clerkship rotations was associated with the performance of the students by using a multi-institutional Progress Test. METHODS: This is a cross-sectional study conducted at nine different Brazilian medical schools that administer the same annual Progress Test for all students. We included information from 1,470 clerkship medical students and analyzed the time of clinical training interruption as the independent variable and the student's scores as the dependent variable. RESULTS: The comparisons of the students' scores between the schools showed that there are differences; however, they cannot be attributed to the time the clerkship rotations were paused. The correlation between the schools' average scores and the time to resume clerkship rotations was not significant for the fifth year (r= -0.298, p=0.436) and for the sixth year (r= -0.440, p=0.240). By using a cubic regression model, the time to resume clerkship rotations could explain 3.4% of the 5-year students' scores (p<0.001) and 0.9% of the 6-year students, without statistical difference (p=0.085). CONCLUSIONS: The differences between the students' scores cannot be attributed to the time when the schools paused the clerkship rotations.

Time of clerkship rotations' interruption during COVID-19 and differences on Progress Test's scores

SUMMARY OBJECTIVES: The transition from face-to-face to remote teaching is yet to be fully understood. In clinical training, traditional teaching must prevail because it is essential for the acquisition of skills and professionalism. However, the responses of each school to the pandemic and the decision on when to resume clerkship rotations were mixed. In this study, we aimed to analyze whether the time to resume clerkship rotations was associated with the performance of the students by using a multi-institutional Progress Test. METHODS: This is a cross-sectional study conducted at nine different Brazilian medical schools that administer the same annual Progress Test for all students. We included information from 1,470 clerkship medical students and analyzed the time of clinical training interruption as the independent variable and the student's scores as the dependent variable. RESULTS: The comparisons of the students' scores between the schools showed that there are differences; however, they cannot be attributed to the time the clerkship rotations were paused. The correlation between the schools' average scores and the time to resume clerkship rotations was not significant for the fifth year (r= -0.298, p=0.436) and for the sixth year (r= -0.440, p=0.240). By using a cubic regression model, the time to resume clerkship rotations could explain 3.4% of the 5-year students' scores (p<0.001) and 0.9% of the 6-year students, without statistical difference (p=0.085). CONCLUSIONS: The differences between the students' scores cannot be attributed to the time when the schools paused the clerkship rotations.

The dimerization of methyl vanillate improves its effect against breast cancer cells via pro-oxidant effect.

Phenolic phytochemicals are a group of organic compounds with potent antioxidant features but can also act as powerful pro-oxidants. These characteristics are effective in reducing metastatic potential in cancer cells, and this effect has been associated with reactive oxygen species (ROS). Methyl vanillate (MV) and its dimer, methyl divanillate (DMV), are potent antioxidants. In the present study, we investigated the effects of MV and DMV on breast cancer cell lines MCF-7 and MDA-MB-231 and compared the results using the non-tumor cell line HB4a. Our results indicated that the compounds performed a pro-oxidant action, increasing the generation of ROS. DMV decreased the viability cell, showing a higher apoptotic effect and inhibition of proliferation than MV on both cell lines, with significant differences between groups (p < 0.05). Some modulation of NOX4, NOX5, and DUOX were observed, but the results did not correlate with the intracellular production of ROS. The dimer showed more effectivity and pro-oxidant effect than MV, impacting cell line MCF-7 in higher extension than MDA-MB-231. In conclusion, and corroborating with reported works, the dimerization of natural phenolic compounds was associated with improved beneficial biological effects as a potential cytotoxic agent to tumor cells.

Antimicrobial potential of plant extracts from the Brazilian Cerrado.

Bacteria are related do different oral diseases, such as dental caries and periodontal disease. Therefore, the control or/and eradication of microorganisms and their by-products is primordial for the success of their treatment. An alternative for decrease bacterial load is the use of plant extracts used in popular medicine. The cytotoxicity and antimicrobial action of extracts of Cariniana rubra Gardiner ex Miers, Senna martiniana, Anadenanthera colubrina (Vell.) Brenan and Spiranthera odoratissima St. Hil. against strains of Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Aggregatibacter actinomyces- tencomitans and Candida albicans were investigated. Cytotoxicity was assessed at concentrations of 1, 10, 40, 80, 100 and 1000 µg/mL by means of the MTT test and compared to a control group with untreated cells. Those with acceptable cytotoxicity had the antimicrobial action measured by the XTT test. As a positive control, sodium hypochlorite was used. Cariniana rubra Gardiner ex Miers had the highest citototoxicity results while Spiranthera odoratissima St. Hil. had the best results, but all extracts showed acceptable cytotoxicity at different concentrations. The plant extracts showed higher activity against A. actinomycetencomitans: Anadenanthera columbrina (Vell.) Brenan (80.52%) at 40 µg/mL, Spiranthera odoratissima St. Hil (78.48%) in 1 µg/mL, Senna martiniana (73.28%) in the concentration of 40 µg/mL and Cariniana rubra Gardiner ex Miers (70.50%) in 10 µg/mL. All extracts analyzed showed acceptable cytotoxicity at different concentrations and were promising for inhibition of the pathogenic microorganisms studied.

Antimicrobial potential of plant extracts from the Brazilian Cerrado

Abstract Bacteria are related do different oral diseases, such as dental caries and periodontal disease. Therefore, the control or/and eradication of microorganisms and their by-products is primordial for the success of their treatment. An alternative for decrease bacterial load is the use of plant extracts used in popular medicine. The cytotoxicity and antimicrobial action of extracts of Cariniana rubra Gardiner ex Miers, Senna martiniana, Anadenanthera colubrina (Vell.) Brenan and Spiranthera odoratissima St. Hil. against strains of Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Aggregatibacter actinomyces- tencomitans and Candida albicans were investigated. Cytotoxicity was assessed at concentrations of 1, 10, 40, 80, 100 and 1000 μg/mL by means of the MTT test and compared to a control group with untreated cells. Those with acceptable cytotoxicity had the antimicrobial action measured by the XTT test. As a positive control, sodium hypochlorite was used. Cariniana rubra Gardiner ex Miers had the highest citototoxicity results while Spiranthera odoratissima St. Hil. had the best results, but all extracts showed acceptable cytotoxicity at different concentrations. The plant extracts showed higher activity against A. actinomycetencomitans: Anadenanthera columbrina (Vell.) Brenan (80.52%) at 40 μg/mL, Spiranthera odoratissima St. Hil (78.48%) in 1 μg/mL, Senna martiniana (73.28%) in the concentration of 40 μg/mL and Cariniana rubra Gardiner ex Miers (70.50%) in 10 μg/mL. All extracts analyzed showed acceptable cytotoxicity at different concentrations and were promising for inhibition of the pathogenic microorganisms studied.

Resumo Bactérias estão relacionadas a diferentes doenças bucais, como a cárie dentária e a doença periodontal. Assim, o controle e/ou erradicação de microrganismos e seus subprodutos é primordial para o sucesso dos tratamentos. Uma alternativa para diminuir a carga bacteriana é a utilização de extratos vegetais utilizados na medicina popular. A citotoxicidade e ação antimicrobiana de extratos de Cariniana rubra Gardinerex Miers, Senna martiniana H.S. Irwin & Barneby, Anadenanthera colubrina (Vell.) Brenan e Spiranthera odoratissima St. Hil. contra cepas de Streptococcus mutans, Enterococcusfaecalis, Staphylococcus aureus, Escherichia coli, Agartibacter actinomycetencomitans e Candida albicans foram investigados. A citotoxicidade foi avaliada nas concentrações de 1, 10, 40, 80, 100 e 1000 μg/mL por meio do teste MTT. Aqueles com citotoxicidade aceitável tiveram a ação antimicrobiana medida pelo teste XTT. Cariniana rubra Gardinerex Miers apresentou os maiores resultados de citototoxicidade, enquanto Spiranthera odoratissima St. Hil. obteve os melhores resultados, mas todos os extratos apresentaram citotoxicidade aceitável em diferentes concentrações. Os extratos vegetais apresentaram maior atividade contra A. actinomycetencomitans: Anadenanthera columbrina (Vell.) Brenan (80,52%) a 40 μg/mL, Spiranthera odoratissima St. Hil (78,48%) em 1 μg/mL, Senna martiniana H.S. Irwin & Barneby (73,28%) na concentração de 40 μg/mL e Cariniana rubra Gardinerex Miers (70,50%) em 10 μg/mL. Todos os extratos analisados apresentaram citotoxicidade aceitável em diferentes concentrações e foram promissores na inibição dos microrganismos patogênicos estudados.

Antimicrobial action, cytotoxicity, calcium ion release, and pH variation of a calcium hydroxide-based paste associated with Myracrodruon urundeuva Allemão extract.

The extract of Myracrodruon urundeuva Allemão (aroeira), as a vehicle, associated with calcium hydroxide (CH) paste was evaluated based on cell viability, antimicrobial action, calcium ion release, and pH variation. Calcium hydroxide with propylene glycol was used as control. The pH variation was measured at 3, 24, 72, 168, 140, 360, and 720 h and calcium ion release was measured on days 7, 15, and 30. Cell viability was assessed with NIH/3T3 cells using MTT and crystal violet assays, after 24, 48, and 72 h. Antibacterial activity was determined by the disc diffusion method, while microbial reduction (Enterococcus faecalis) was evaluated using the time-kill test. The CH paste formulated with aroeira showed antibacterial activity against Enterococcus faecalis and further did not interfere with pH, calcium ion release, or cell viability; moreover, the formulation had antimicrobial activity and could serve as a vehicle for CH paste.

Evaluation of Myrcia bella in murine osteosarcoma cells: Effect of the extract and enriched fractions of tannins and flavonoids.

Myrcia bella Cambess (Myrtaceae) is an important and common plant, native to the Brazilian Cerrado, with cytotoxicity, antimicrobial, and antidiabetic properties. Therefore, the effects of crude hydroalcoholic extract (CE) and fractions of ellagitannins (ELT) and flavonoids (FV) from Myrcia bella leaves were evaluated in a UMR-106 murine osteosarcoma cells and MC3T3 (normal cell). Cell viability and migration, production of reactive oxygen species (ROS) and matrix metalloproteinase (MMP) -2 and -9 activities were evaluated. In general, CE (80 µg/mL), ELT (160 µg/mL) and FV (64 µg/mL) reduced cell viability (p < 0.05). FV (64 µg/mL) was more effective in inhibition of cell migration, ROS production, and MMP-2 activity when compared to CE and ELT. Myrcia bella a rich source of phenolic compounds and its fraction of flavonoids have cytotoxic effects on osteosarcoma cells, preserving the viability of normal osteoblasts. Due to its antioxidant capacity, flavonoid may be a new therapeutic strategy for cancer.

Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode.

The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1ß, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 ß, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.

Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode

Abstract The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1β, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 β, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.

Resumo A resposta de defesa do hospedeiro ao desafio microbiano que emerge do sistema de canais radiculares leva à periodontite apical. Os objetivos deste estudo foram avaliar a expressão de citocinas pró e anti-inflamatórias e Óxido Nítrico (NO) por macrófagos após interação com Enterococcus faecalis no modo: planctônio e de biofilme desalojado; biofilme intacto estimulado por hidróxido de cálcio (CH), CH e clorexidina ou Pasta Tri Antibiótica (TAP). Para isto, a cultura de macrófagos originados de monócitos do sangue periférico de humanos (N=8) foi exposta aos diferentes tipos de bactéria por 24 horas. Então, a quantificação da produção de of Fator de Necrose Tumoral- alfa (TNF-α), interleucina (IL)-1β, IL-6, IL-10 e NO por macrófagos se deu por meio do Luminex xMAP e reação de Greiss, respectivamente. Além dos potenciais efeitos terapêuticos desses compostos, sua atividade antimicrobiana contra E. faecalis também foi testada através microscopia confocal. Os dados dos experimentos foram analisados através do teste de Kruskal-Wallis com Dunn`s post hoc (α < 0.05). Bactéria em modo de biofilme desalojado se mostrou mais agressivo ao sistema imune que as bactérias planctônicas e controle negativo induzindo a maior excreção de NO e TNF-α. Em relação ao biofilme intacto, a atividade antimicrobiana mais fraca ocorreu no grupo de CH. Os grupos CHX e TAP aumentaram significativamente a porcentagem de bactérias mortas na mesma extensão. Interessantemente, o biofilme por ele mesmo não induziu a liberação de citocinas pro-inflamatórias - exceto por NO - enquanto que o biofilme tratado com TAP ou pastas a base de CH aumentaram os níveis de IL-6; e TNF-α e IL-1 β respectivamente. Em contraste, os níveis da potente citocina anti-inflamatória (IL-10) foram aumentados pelo grupo TAP.

Effects of Qualea grandiflora Extract on the Expression of MMP-14 and HIF-1α in Cultured Fibroblasts and Preosteoblasts

Abstract Background: Qualea grandiflora (QG) (Vochysiaceae), also known as "pau-ferro", "pau-terra" or "pau-de-tucano", is a very common deciduous tree in the Brazilian Cerrado used in traditional medicine to treat inflammations, ulcers, diarrhea, and infections. There are reports in the scientific literature that demonstrate the medicinal effects of the bark and leaf of the QG. However, studies involving this plant are rather imited. Aim of the study: To perform the phytochemical analysis of the QG hydroalcoholic extract (HAE) of leaves, and to investigate it effects on fibroblast and preosteoblasts. Methods: Phytochemical analysis was done by HPLC-DAD. Murine NIH/3T3 fibroblasts and MC3T3-E1 preosteoblasts cell lines (ATCC) were used for the experiments. Cell viability was assessed by the MTT colorimetric assay and the expression of MMP-14 and HIF-1α by immunofluorescence. Results and conclusion: The following compounds were identified by HPLC-DAD, such as quinic acid, ethyl galate, ellagic acid derivatives as O-methylellagic acid O-galloyl, O-methylellagic acid O-deoxyhexoside, galloyl derivatives, flavonol glycoside as kaempferol-O-deoxyhexoside, quercetin-O-deoxyhexoside, myricetin-O-deoxyhexoside and the pentacyclic triterpene arjunglucoside. Cell viability results demonstrated no cytotoxic effects in the studied concentrations. We found in QG HAE some compounds with therapeutic properties that can increase the expression of MMP-14 and HIF-1α, in fibroblasts and preosteoblasts. These data suggest that QG HAE has an action on these two molecules widely involved in physiological conditions, such as collagen remodeling, bone development and growth and pathological processes as HIF signaling in cancer metastasis.

Updating the role of matrix metalloproteinases in mineralized tissue and related diseases.

Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.

Effect of hydroalcoholic extract of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on the viability and activity of microcosm biofilm and on enamel demineralization.

OBJECTIVES: The aim of this study was to assess the effect of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves hydroalcoholic extracts on viability and metabolism of a microcosm biofilm and on enamel demineralization prevention. METHODOLOGY: Microcosm biofilm was produced on bovine enamel using inoculum from pooled human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. The biofilm was daily-treated with the extracts for 1 min. At the end, it was analyzed with respect to viability by fluorescence, CFU counting and extracellular polysaccharides (phenol-sulphuric acid colorimetric assay) and lactic acid (enzymatic assay) production. The demineralization was measured by TMR. The data were compared using ANOVA or Kruskal-Wallis (p<0.05). RESULTS: M. urundeuva All. at 100, 10 and 0.1 µg/mL and Q. grandiflora Mart. at 100 and 0.1 µg/mL reduced biofilm viability similarly to positive control (chlorhexidine) and significantly more than the negative-vehicle control (35% ethanol). M. urundeuva at 1000, 100 and 0.1 µg/mL were able to reduce both lactobacilli and mutans streptococci CFU counting, while Q. grandiflora (1000 and 1.0 µg/mL) significantly reduced mutans streptococci CFU counting. On the other hand, the natural extracts were unable to significantly reduce extracellular polysaccharides and lactic acid productions neither the development of enamel carious lesions. CONCLUSIONS: The extracts showed antimicrobial properties on microcosm biofilm, however, they had no effect on biofilm metabolism and caries protection.

In Vitro Antimicrobial Effect of Bioadhesive Oral Membrane with Chlorhexidine Gel.

This study aimed to evaluate in vitro the antimicrobial effect of a bioadhesive chitosan-based oral membrane with chlorhexidine for local treatment of infections in the oral tissues. Five oral membranes of different compositions were tested: 5% chitosan (G1); 5% chitosan ± 0.2% chlorhexidine (G2), 5% chitosan ± 0.6% chlorhexidine (G3), 5% chitosan ± 1.0% chlorhexidine (G4), and 5% chitosan ± 2.0% chlorhexidine (G5). Also, five gel types were tested according to the following compositions: 5% chitosan gel (G6), 0.2% chlorhexidine gel (G7), 2.0% chlorhexidine gel (G8), 5% chitosan gel ± 0.2% chlorhexidine gel (G9), and 5% chitosan gel ± 2.0% chlorhexidine gel (G10). The antimicrobial action of the samples was tested against Candida albicans and Streptococcus mutans through antibiogram by measuring the inhibition halos. Data were statistically analyzed by Kruskal-Wallis and one-way ANOVA followed by Tukey test (p<0.05). The 2.0% chlorhexidine membrane (G5) and the disks containing 2.0% chlorhexidine gel (G8) showed the greatest inhibition halos for both microorganisms, with statistically significant difference when compared to others tested groups (p=0.008) only for Candida albicans inhibitions results. All the other formulations of membranes and gels showed inhibition halos, but without statistically significant difference. The bioadhesive chitosan-based oral membrane with 2% chlorhexidine and 2% chlorhexidine gel were the most effective in inhibiting the tested microorganisms.

Isolation and characterization of progenitor cells from surgically created early healing alveolar defects in humans: A preliminary study.

BACKGROUND: The granulation tissue present in surgically-created early healing sockets has been considered as a possible source of osteoprogenitor cells for periodontal regeneration, as demonstrated in animal studies. However, the in vitro osteogenic properties of tissue removed from human surgically-created early healing alveolar defects (SC-EHAD) remains to be established, being that the aim of this study. METHODS: Surgical defects were created in the edentulous ridge of two systemically healthy adults. The healing tissue present in these defects was removed 21 days later for the establishment of primary culture. The in vitro characteristics of the cultured cells were determined by Armelin method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, immunohistochemistry, alkaline phosphatase (ALP) activity, mineralization assay, and flow cytometry for detection of stem cells/osteoprogenitor cell markers. RESULTS: Cells were able to adhere to the plastic and assumed spindle-shaped morphology at earlier passages, changing to a cuboidal one with increasing passages. Differences in the proliferation rate were observed with increasing passages, suggesting osteogenic differentiation. ALP and mineralization activities were detected in conventional and osteogenic medium. Fresh samples of SC-EHAD tissue exhibited CD34- and CD45- phenotypes. Cells at later passages (14th) exhibited CD34- , CD45- , CD105- , CD166- , and collagen type I+ phenotype. CONCLUSION: Tissue removed from SC-EHAD is a possible source of progenitor cells.