Subtle white matter intensity changes on fluid-attenuated inversion recovery imaging in patients with ischaemic stroke.

Leukoaraiosis is a neuroimaging marker of small-vessel disease that is characterized by high signal intensity on fluid-attenuated inversion recovery MRI. There is increasing evidence from pathology and neuroimaging suggesting that the structural abnormalities that characterize leukoaraiosis are actually present within regions of normal-appearing white matter, and that the underlying pathophysiology of white matter damage related to small-vessel disease involves blood-brain barrier damage. In this study, we aim to verify whether leukoaraiosis is associated with elevated signal intensity on fluid-attenuated inversion recovery imaging, a marker of brain tissue free-water accumulation, in normal-appearing white matter. We performed a cross-sectional study of adult patients admitted to our hospital with a diagnosis of acute ischaemic stroke or transient ischaemic attack. Leukoaraiosis was segmented using a semi-automated method involving manual outlining and signal thresholding. White matter regions were segmented based on the probabilistic tissue maps from the International Consortium for Brain Mapping 152 atlas. Also, normal-appearing white matter was further segmented based on voxel distance from leukoaraiosis borders, resulting in five normal-appearing white matter strata at increasing voxel distances from leukoaraiosis. The relationship between mean normalized fluid-attenuated inversion recovery signal intensity on normal-appearing white matter and leukoaraiosis volume was studied in a multivariable statistical analysis using linear mixed modelling, having normal-appearing white matter strata as a clustering variable. One hundred consecutive patients meeting inclusion and exclusion criteria were selected for analysis (53% female, mean age 68 years). Mean normalized fluid-attenuated inversion recovery signal intensity on normal-appearing white matter was higher in the vicinity of leukoaraiosis and progressively lower at increasing distances from leukoaraiosis. In a multivariable analysis, the mean normalized fluid-attenuated inversion recovery signal intensity on normal-appearing white matter was positively associated with leukoaraiosis volume and age (B = 0.025 for each leukoaraiosis quartile increase; 95% confidence interval 0.019-0.030). This association was found similarly across normal-appearing white matter strata. Voxel maps of the mean normalized fluid-attenuated inversion recovery signal intensity on normal-appearing white matter showed an increase in signal intensity that was not adjacent to leukoaraiosis regions. Our results show that normal-appearing white matter exhibits subtle signal intensity changes on fluid-attenuated inversion recovery imaging that are related to leukoaraiosis burden. These results suggest that diffuse free-water accumulation is likely related to the aetiopathogenic processes underlying the development of white matter damage related to small-vessel disease.

Association between obesity and COVID-19 mortality and length of stay in intensive care unit patients in Brazil: a retrospective cohort study.

The present study aimed to evaluate the association between obesity and COVID-19 mortality and length of stay in ICU patients, and how these associations were modified by age groups. We performed a retrospective multicenter cohort study with data obtained from a hospital-based registry. The sample consisted of 8183 ICU hospitalized patients who tested positive for SARS-CoV-2. Cox proportional models were used to evaluate the association between BMI categories and COVID-19 mortality and generalized linear models for the length of stay in the ICU. After adjusting for confounders, those in the younger group with severe obesity had an increased risk of COVID-19 mortality compared to those with normal/overweight (HR 1.27; 95% CI 1.01-1.61). An increased risk of death was also observed for patients with underweight (HR 3.74; 95% CI 1.39-10.07). For patients aged ≥ 60 year, mild/moderate obesity was associated with reduced mortality risk (HR 0.87; 95% CI 0.78-0.97). For the age group < 60 year, the length of stay in ICU for those patients with severe obesity was 35% higher compared to the normal/overweight category (eß 1.35; 95% CI 1.21-1.51). Conversely, for the survivors in the underweight category, the length of stay in ICU was 51% lower compared to the normal/overweight group (eß 0.49; 95% CI 0.31-0.78). In the age group ≥ 60 year, mild/moderate obesity was associated with an increased length of stay in the ICU (eß 1.10; 95% CI 1.01-1.21), adjusting for confounders. These findings could be helpful for health professionals to identify subgroups at higher risk for worse outcomes.

Social Distancing, Stroke Admissions and Stroke Mortality During the COVID-19 Pandemic: A Multicenter, Longitudinal Study.

OBJECTIVES: We aimed to evaluate the relationship between social distancing, stroke admissions and stroke mortality during the COVID-19 pandemic, while accounting for the rate of COVID-19 admissions. METHODS: We performed a longitudinal analysis of a multicenter, prospective, hospital-based registry of intensive care units from 19 hospitals from Brazil, comprising a 14-month period of the COVID-19 pandemic. We investigated whether the daily rate of admissions (DRAstroke) and daily mortality rate for stroke were associated with the social distancing index (SDI), taking into account the daily rate of admissions for COVID-19 (DRACOVID) in univariate and multivariate regression models. We also compared the clinical characteristics of patients with stroke admitted before and during the pandemic. RESULTS: We found that DRAstroke decreased significantly in association with a strong rise in the SDI during the early months of the pandemic. However, in the latter period of the pandemic, only minor changes were observed in the SDI, and still, DRAstroke was inversely associated with the DRACOVID. Throughout the pandemic, higher SDI and DRACOVID were associated with higher in-hospital mortality for stroke. CONCLUSIONS: The severity of surges of the COVID-19 pandemic were independently and persistently associated with declines in stroke admissions, even during periods when social distancing policies were not intensified.

Intra-articular injection of culture-expanded mesenchymal stem cells with or without addition of platelet-rich plasma is effective in decreasing pain and symptoms in knee osteoarthritis: a controlled, double-blind clinical trial.

PURPOSE: To compare the clinical and laboratory outcomes of intra-articular injections of culture-expanded bone-derived mesenchymal stem cells (MSCs) with or without platelet-rich plasma (PRP) to intra-articular corticosteroid injections for the treatment of knee osteoarthritis (OA). METHODS: Forty-seven patients with radiographic and symptomatic knee OA were randomized into three groups for intra-articular injections: autologous bone marrow-derived culture-expanded MSCs (n = 16); autologous bone marrow-derived culture-expanded MSCs + PRP (n = 14); and corticosteroid (n = 17). The outcomes were assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS) and range of motion (ROM) at baseline, 1, 2, 3, 6, 9 and 12 months and intra-articular cytokines analysis at baseline, 6 and 12 months postoperatively. RESULTS: The three groups showed significant improvement in most KOOS domains and global score at 1st month and all domains and global score at 12-month follow-up (p < 0.05). At the 1st month, only the MSCs group showed significant differences in KOOS symptoms domain (p = 0.003). The MSCs and MSCs + PRP groups showed the highest percentage of improvement in most KOOS domains and global score compared to the corticosteroid group. All three groups showed a significant reduction in intra-articular levels of human interleukin-10 cytokine, from baseline to 12 months (p < 0.05). CONCLUSION: An intra-articular injection of bone marrow-derived culture-expanded MSCs with or without the addiction of PRP is effective in improving the function and decreasing symptoms caused by knee OA at 12-month follow-up. LEVEL OF EVIDENCE: II.

Intra-articular injections of expanded mesenchymal stem cells with and without addition of platelet-rich plasma are safe and effective for knee osteoarthritis.

PURPOSE: To compare the effectiveness and safety of intra-articular injections of autologous expanded mesenchymal stromal stem cells alone (MSCs), or in combination with platelet-rich plasma (MSCs + PRP), in patients with knee osteoarthritis. METHODS: Eighteen patients (57.6 ± 9.6 years) with radiographic symptomatic knee osteoarthritis (Dejour grades II-IV) were randomized to receive intra-articular injections of MSCs (n = 9) or MSCs + PRP (n = 9). Injections were performed 2-3 weeks after bone marrow aspiration (± 80-100 ml) which was obtained from both posterior iliac crests. RESULTS: The Knee Injury and Osteoarthritis Outcome Score (KOOS) improved significantly throughout the 12 months for both groups (p < 0.05). No statistically significant differences between groups were found in KOOS subscales and global score improvements at 12-month end-point (n.s.). The MSCs group showed significant improvements in the pain, function and daily living activities, and sports and recreational activities subscales (p < 0.05). Similarly, the MSCs + PRP group showed significant improvements in the pain, function and daily living activities and quality of life subscales (p < 0.05). The average number of fibroblast colony forming units (CFU-F) was 56.8 + 21.9 for MSCs group and 50.7 ± 21.7 for MSCs + PRP group. Minimal adverse effects were seen in both groups (10 adverse events, in 5 patients). CONCLUSIONS: Intra-articular injections of expanded MSCs alone or in combination with PRP are safe and have a beneficial effect on symptoms in patients with symptomatic knee osteoarthritis. Adding PRP to the MSCs injections did not provide additional benefit. These results are encouraging and support the recommendation of this minimally invasive procedure in patients with knee osteoarthritis, without requiring hospitalization. The CFU-F results may be used as reference for future research. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

A T Cell View of the Bone Marrow.

The majority of T cells present in the bone marrow (BM) represent an activated/memory phenotype and most of these, if not all, are circulating T cells. Their lodging in the BM keeps them activated, turning the BM microenvironment into a "memory reservoir." This article will focus on how T cell activation in the BM results in both direct and indirect effects on the hematopoiesis. The hematopoietic stem cell niche will be presented, with its main components and organization, along with the role played by T lymphocytes in basal and pathologic conditions and their effect on the bone remodeling process. Also discussed herein will be how "normal" bone mass peak is achieved only in the presence of an intact adaptive immune system, with T and B cells playing critical roles in this process. Our main hypothesis is that the partnership between T cells and cells of the BM microenvironment orchestrates numerous processes regulating immunity, hematopoiesis, and bone remodeling.

Platelet-Rich Plasma Obtained with Different Anticoagulants and Their Effect on Platelet Numbers and Mesenchymal Stromal Cells Behavior In Vitro.

There are promising results in the use of platelet-rich plasma (PRP) for musculoskeletal tissue repair. However, the variability in the methodology for its obtaining may cause different and opposing findings in the literature. Particularly, the choice of the anticoagulant is the first definition to be made. In this work, blood was collected with sodium citrate (SC), ethylenediaminetetraacetic acid (EDTA), or anticoagulant citrate dextrose (ACD) solution A, as anticoagulants, prior to PRP obtaining. Hematological analysis and growth factors release quantification were performed, and the effects on mesenchymal stromal cell (MSC) culture, such as cytotoxicity and cell proliferation (evaluated by MTT method) and gene expression, were evaluated. The use of EDTA resulted in higher platelet yield in whole blood; however, it induced an increase in the mean platelet volume (MPV) following the blood centrifugation steps for PRP obtaining. The use of SC and ACD resulted in higher induction of MSC proliferation. On the other hand, PRP obtained in SC presented the higher platelet recovery after the blood first centrifugation step and a minimal change in MSC gene expression. Therefore, we suggest the use of SC as the anticoagulant for PRP obtaining.

Platelet-rich plasma releasate differently stimulates cellular commitment toward the chondrogenic lineage according to concentration.

Platelet-rich plasma has been used to treat articular cartilage defects, with the expectations of anabolic and anti-inflammatory effects. However, its role on cellular chondrogenic or fibrogenic commitment is still a controversy. Herein, the role of platelet-rich plasma releasate, the product obtained following platelet-rich plasma activation, on cellular commitment toward the chondrogenic lineage was evaluated in vitro. Human nasoseptal chondrogenic cells and human bone marrow mesenchymal stromal cells were used as cell types already committed to the chondrogenic lineage and undifferentiated cells, respectively, as different concentrations of platelet-rich plasma releasate were tested in comparison to commonly used fetal bovine serum. Low concentration of platelet-rich plasma releasate (2.5%) presented similar effects on cellular growth compared to 10% fetal bovine serum, for both cell types. In a three-dimensional culture system, platelet-rich plasma releasate alone did not induce full nasoseptal chondrogenic cells cartilage-like pellet formation. Nonetheless, platelet-rich plasma releasate played a significant role on cell commitment as high-passage nasoseptal chondrogenic cells only originated cartilage-like pellets when expanded in the presence of platelet-rich plasma releasate rather than fetal bovine serum. Histological analyses and measurements of pellet area demonstrated that even low concentrations of platelet-rich plasma releasate were enough to prevent nasoseptal chondrogenic cells from losing their chondrogenic potential due to in vitro expansion thereby promoting their recommitment. Low concentration of platelet-rich plasma releasate supplemented in chondrogenic medium also increased the chondrogenic potential of mesenchymal stromal cells seeded on collagen-hyaluronic acid scaffolds, as observed by an increase in chondrogenic-related gene expression, sulfated glycosaminoglycan production, and compressive modulus following in vitro culture. On the contrary, higher concentration of platelet-rich plasma releasate (10%) hampered some of these features. In conclusion, platelet-rich plasma releasate was able to prevent cellular chondrogenic capacity loss, inducing regain of their phenotype, and modulate cell commitment. Our data support the hypothesis of platelet-rich plasma chondrogenic potential, allowing fetal bovine serum substitution for platelet-rich plasma releasate at specific concentrations in culture medium when chondrogenic commitment is desired on specific cell types and moments of culture.

The bone marrow endosteal niche: how far from the surface?

Hematopoietic stem cells (HSC) self-renewal takes place in the same microenvironment in which massive hematopoietic progenitor proliferation, commitment, and differentiation will occur. This is only made possible if the bone marrow microenvironment comprises different specific niches, composed by different stromal cells that work in harmony to regulate all the steps of the hematopoiesis cascade. Histological and functional assays indicated that HSC and multipotent progenitors preferentially colonize the endosteal and subendosteal regions, in close association with the bone surface. Conversely, committed progenitors and differentiated cells are distributed in the central and perisinusoidal regions, respectively. Over the last decade, many investigative teams sought to define which cell types regulate the HSC niche, how they are organized, and to what extent they interface with each other. System dynamics requires different stromal cells to operate distinct functions over similar HSC pools rather than a single stromal cell type controlling everything. Therefore, our focus herein is to depict the players in the endosteal and subendosteal regions, named the endosteal niche, a necessary step to better understand the interactions of the HSC within the niche and to identify potential targets to manipulate and/or modulate normal and malignant HSC behavior.

Human bone marrow mesenchymal progenitors: perspectives on an optimized in vitro manipulation.

When it comes to regenerative medicine, mesenchymal stem cells (MSCs) are considered one of the most promising cell types for use in many cell therapies and bioengineering protocols. The International Society of Cellular Therapy recommended minimal criteria for defining multipotential MSC is based on adhesion and multipotency in vitro, and the presence or absence of select surface markers. Though these criteria help minimize discrepancies and allow some comparisons of data generated in different laboratories, the conditions in which cells are isolated and expanded are often not considered. Herein, we propose and recommend a few procedures to be followed to facilitate the establishment of quality control standards when working with mesenchymal progenitors isolation and expansion. Following these procedures, the classic Colony-Forming Unit-Fibroblast (CFU-f) assay is revisited and three major topics are considered to define conditions and to assist on protocol optimization and data interpretation. We envision that the creation of a guideline will help in the identification and isolation of long-term stem cells and short-term progenitors to better explore their regenerative potential for multiple therapeutic purposes.

Improvement of cardiac function by placenta-derived mesenchymal stem cells does not require permanent engraftment and is independent of the insulin signaling pathway.

INTRODUCTION: The objective of this work was to evaluate the efficacy of placenta-derived mesenchymal stem cell (MSC) therapy in a mouse model of myocardial infarction (MI). Since MSCs can be obtained from two different regions of the human term placenta (chorionic plate or villi), cells obtained from both these regions were compared so that the best candidate for cell therapy could be selected. METHODS: For the in vitro studies, chorionic plate MSCs (cp-MSCs) and chorionic villi MSCs (cv-MSCs) were extensively characterized for their genetic stability, clonogenic and differentiation potential, gene expression, and immunophenotype. For the in vivo studies, C57Bl/6 mice were submitted to MI and, after 21 days, received weekly intramyocardial injections of cp-MSCs for 3 weeks. Cells were also stably transduced with a viral construct expressing luciferase, under the control of the murine stem cell virus (MSCV) promoter, and were used in a bioluminescence assay. The expression of genes associated with the insulin signaling pathway was analyzed in the cardiac tissue from cp-MSCs and placebo groups. RESULTS: Morphology, differentiation, immunophenotype, and proliferation were quite similar between these cells. However, cp-MSCs had a greater clonogenic potential and higher expression of genes related to cell cycle progression and genome stability. Therefore, we considered that the chorionic plate was preferable to the chorionic villi for the isolation of MSCs. Sixty days after MI, cell-treated mice had a significant increase in ejection fraction and a reduction in end-systolic volume. This improvement was not caused by a reduction in infarct size. In addition, tracking of cp-MSCs transduced with luciferase revealed that cells remained in the heart for 4 days after the first injection but that the survival period was reduced after the second and third injections. Quantitative reverse transcription-polymerase chain reaction revealed similar expression of genes involved in the insulin signaling pathway when comparing cell-treated and placebo groups. CONCLUSIONS: Improvement of cardiac function by cp-MSCs did not require permanent engraftment and was not mediated by the insulin signaling pathway.

A novel classification system for evolutionary aging theories.

Theories of lifespan evolution are a source of confusion amongst aging researchers. After a century of aging research the dispute over whether the aging process is active or passive persists and a comprehensive and universally accepted theoretical model remains elusive. Evolutionary aging theories primarily dispute whether the aging process is exclusively adapted to favor the kin or exclusively non-adapted to favor the individual. Interestingly, contradictory data and theories supporting both exclusively programmed and exclusively non-programmed theories continue to grow. However, this is a false dichotomy; natural selection favors traits resulting in efficient reproduction whether they benefit the individual or the kin. Thus, to understand the evolution of aging, first we must understand the environment-dependent balance between the advantages and disadvantages of extended lifespan in the process of spreading genes. As described by distinct theories, different niches and environmental conditions confer on extended lifespan a range of fitness values varying from highly beneficial to highly detrimental. Here, we considered the range of fitness values for extended lifespan and develop a fitness-based framework for categorizing existing theories. We show that all theories can be classified into four basic types: secondary (beneficial), maladaptive (neutral), assisted death (detrimental), and senemorphic aging (varying between beneficial to detrimental). We anticipate that this classification system will assist with understanding and interpreting aging/death by providing a way of considering theories as members of one of these classes rather than consideration of their individual details.

Avaliação da influência da translucidez de pinos de fibra de vidro na resistência adesiva de um cimento autoadesivo / Evaluation of influence of translucency of fiberglass post in bond strength of a self-adhesive cement

Avaliar a resistência adesiva de um cimento autoadesivo com uso de pinos de fibra de vidro translúcidos ou não e avaliar possíveis diferenças nas diferentes regiões do canal radicular. Métodos - Quarenta incisivos centrais superiores humanos fornecidos pelo banco de dentes da Universidade Federal Fluminense-RJ foram instrumentados com a broca de maior calibre do sistema do pino utilizado. As amostras foram divididas em dois grupos de n=20 denominados de G1 e G2. Foram seccionadas e levadas ao ensaio de cisalhamento por extrusão. O teste t-Student foi utilizado para comparar a interação entre os grupos e entre as regiões do canal radicular. Resultados - A média da resistência adesiva para descolar o pino intracanal foi de 11,42 Mpa no G1 e 11,04 Mpa no G2. Não houve diferença significativa entre as amostras de pinos de fibra de vidro translúcido e opaco (p> 0.05) e nem entre as diferentes regiões do canal radicular para grupo G1 e G2 (p> 0.05). Conclusão - Pode-se concluir que não há influência quanto à translucidez do pino de fibra de vidro cimentado na qualidade de adesão intracanal quando utilizado um cimento autoadesivo...

To evaluate the bond strength of a self-adhesive cement with use of pins fiberglass translucent or not and to assess possible differences in different regions of the root canal. Methods - Forty human maxillary central incisors tooth bank provided by the Universidade Federal Fluminense-RJ were instrumented with larger-diameter drill pin system used. The samples were divided into two groups of n=20 called G1 and G2. Were selected and taken to a shear extrusion. The Student t test was used to compare the interaction between groups and between regions of the root canal. Results - The average bond strength to take off the pin intracanal was 11.42 MPa in G1 and 11.04 MPa in G2. There was no significant difference between samples of reinforced fiberglass translucent and opaque (p> 0.05) or between different regions of the root canal for G1 and G2 (p> 0.05). Conclusion - We can conclude that there is no influence on the translucency of the glass fiber pin cemented in the quality of intracanal adhesion when used a self-adhesive cement...

Molecular signature and in vivo behavior of bone marrow endosteal and subendosteal stromal cell populations and their relevance to hematopoiesis.

In the bone marrow cavity, hematopoietic stem cells (HSC) have been shown to reside in the endosteal and subendosteal perivascular niches, which play specific roles on HSC maintenance. Although cells with long-term ability to reconstitute full hematopoietic system can be isolated from both niches, several data support a heterogenous distribution regarding the cycling behavior of HSC. Whether this distinct behavior depends upon the role played by the stromal populations which distinctly create these two niches is a question that remains open. In the present report, we used our previously described in vivo assay to demonstrate that endosteal and subendosteal stromal populations are very distinct regarding skeletal lineage differentiation potential. This was further supported by a microarray-based analysis, which also demonstrated that these two stromal populations play distinct, albeit complementary, roles in HSC niche. Both stromal populations were preferentially isolated from the trabecular region and behave distinctly in vitro, as previously reported. Even though these two niches are organized in a very close range, in vivo assays and molecular analyses allowed us to identify endosteal stroma (F-OST) cells as fully committed osteoblasts and subendosteal stroma (F-RET) cells as uncommitted mesenchymal cells mainly represented by perivascular reticular cells expressing high levels of chemokine ligand, CXCL12. Interestingly, a number of cytokines and growth factors including interleukin-6 (IL-6), IL-7, IL-15, Hepatocyte growth factor (HGF) and stem cell factor (SCF) matrix metalloproteases (MMPs) were also found to be differentially expressed by F-OST and F-RET cells. Further microarray analyses indicated important mechanisms used by the two stromal compartments in order to create and coordinate the "quiescent" and "proliferative" niches in which hematopoietic stem cells and progenitors reside.

Senemorphism: a novel perspective on aging patterns and its implication for diet-related biology.

Aging can be described as the accumulation of changes in organisms over time. Aging in organisms undergoing caloric restriction (CR) is widely considered as a slowed version of aging under ad libitum (AL) conditions. However, here we argue that aging under optimized CR is fundamentally different from aging under AL based on the following facts: (1) Comparing the two dietary groups, several age-related changes run in the opposite direction over time; (2) Switching from an AL to a CR diet clearly reverts (not only delays) several "normal" accumulated changes; (3) major causes of death are as different between both groups as they are between species. These observations support the idea that CR and AL initially modulate different metabolic and physiological programs, which exclusively over time generate two biologically different organisms. Such distinct diet-related senescence is analogous to the divergent aging processes and causes of death observed between castes of social insects, such as queens versus workers ("caste-related-senescence") and also between breeding versus non-breeding semelparous animals ("reproduction-related-senescence"). All these aging phenotypes are different not because they accumulate changes at a different rate, but because they accumulate different changes over time. Thus, the environment does not simply affect the individual aging rate through stochastic effects (e.g. U.V.) but also modulates the activation of a particular program/strategy that influences lifespan (e.g. caste, calorie intake). We refer to the environment-dependent aging patterns encoded by the genome as "senemorphism". Based on this idea we propose experimental schemes for aging, evolution and biomedical research.

Arnica montana e desordens musculares mastigatórias / Arnica montana and disorders masticatory muscle

As desordens musculares geralmente estão presentes na Disfunção Temporomandibular (DTM). Sua principal sintomatologia é dor, edema, proveniente de injúria tecidual e inflamação. O tratamento das DTMs consiste em tratamento suporte para alívio da sintomatologia e “definitivo” para eliminar as causas e fatores que são perpetuantes. O uso de antiinflamatórios (AINEs), relaxantes musculares, placas oclusais, fitoterápicos com ação antiinflamatória como Arnica Montana são indicados como tratamento suporte. A Arnica montana tem sido usada para redução de inflamação e dor causada por entorse, contusões e ferimentos. Sua principal ação é inibição da ativaçãodo fator de transcrição celular NF- қB.

Identification of periodontal pathogens in healthy periimplant sites.

PURPOSE: : The aim of this study was to evaluate the presence of periodontopathogens in subgingival periimplant sites in partially edentulous patients using polymerase chain reaction procedures, with regard to areas with clinical and radiographic signs of health and areas presenting periimplant disease. MATERIALS AND METHODS: : Thirty nonsmoking, partially edentulous patients, aged 30 to 76 years, were included in this study and divided in 3 groups according their clinical and radiographic characteristics. Group A (n = 10) presented periimplant health, group B (n = 10) presented periimplant mucositis, and group C (n = 10) were patients with periimplantitis. Periimplant tissues were clinically examined as regards the color of mucosae, presence of bacterial plaque, depth and bleeding on probing, and local suppuration. History of periodontal disease was also considered. Radiographic analysis evaluated the presence of bone loss around the implant. Samples of periimplant crevicular fluid were collected to analyze the presence of periodontal pathogens, Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf), and Treponema denticola (Td). RESULTS: : The results showed that the history of periodontal disease is associated with periimplant disease. The bacteria Aa, Pg, Pi, Td, and Tf were present in periimplant sites clinically and radiographically characterized, as healthy periimplant tissues, mucositis, and periimplantitis. CONCLUSIONS: : We concluded that Aa, Pg, Pi, Td, and Tf are present in healthy and diseased conditions. Therefore, these periodontal pathogens are not strictly related to periimplant disease sites.

Prospective identification and skeletal localization of cells capable of multilineage differentiation in vivo.

A prospective in vivo assay was used to identify cells with potential for multiple lineage differentiation. With this assay, it was first determined that the 5-fluorouracil resistant cells capable of osseous tissue formation in vivo also migrated toward stromal derived factor-1 (SDF-1) in vitro. In parallel, an isolation method based on fluorescence-activated cell sorting was employed to identify a very small cell embryonic-like Lin-/Sca-1+CD45- cell that with as few as 500 cells was capable of forming bone-like structures in vivo. Differential marrow fractionation studies determined that the majority of the Lin-Sca-1+CD45- cells reside in the subendosteal regions of marrow. To determine whether these cells were capable of differentiating into multiple lineages, stromal cells harvested from Col2.3 Delta TK mice were implanted with a gelatin sponge into SCID mice to generate thymidine kinase sensitive ossicles. At 1.5 months, 2,000 green fluorescent protein (GFP)+ Lin-Sca-1+CD45- cells were injected into the ossicles. At harvest, colocalization of GFP-expressing cells with antibodies to the osteoblast-specific marker Runx-2 and the adipocyte marker PPAP gamma were observed. Based on the ability of the noncultured cells to differentiate into multiple mesenchymal lineages in vivo and the ability to generate osseous tissues at low density, we propose that this population fulfills many of the characteristics of mesenchymal stem cells.

The effect of titanium topography features on mesenchymal human stromal cells' adhesion.

OBJECTIVE: The aim of this study was to evaluate the effect of two kinds of dental implants surfaces with their own characteristics on human marrow stromal cells' adhesion. MATERIAL AND METHODS: Fifty-six titanium discs (28 machined and 28 acid etched) were used. Machined (MS) and acid-etched surfaces (ES) were analyzed using a scanning electron microscope, energy dispersing spectroscopy (EDS), contact angle analysis and human marrow stromal cells' culture. RESULTS: Significant differences were observed in the topography and wetability of the tested surfaces. However, etched surfaces presented a high level of wetability when compared with machined surfaces. Contact angles showed considerable differences between etched and machined surfaces (Friedman test P<0.05). EDS analysis showed the same composition on both the surfaces tested. Counting of adhered cells on both types of surfaces showed that there is no statistical significance in human marrow stromal cells' adhesion after 18 h (Mann-Whitney test P>0.05). CONCLUSION: The present study concludes that modifications on the titanium implant surfaces roughness may promote differences in the morphology of bone marrow stromal cells. Nevertheless, in this microenvironment, no interference in the adhesion phenomenon was noted.

Influência do acabamento e polimento de cimentos de ionômero de vidro na rugosidade superficial / Influence of the finishing and polishing procedures on the ionomer cements superficial roughness

O objetivo do artigo foi o de comparar métodos de acabamento e polimento superficial dos materiais ionoméricos Ketac-Fil plus e Vitro-Fil. Foram obtidas réplicas em resina Epóxi dos pré-molares restaurados e as superfícies analisadas em MEV e a rugosidade superficial em rugosímetro. Os discos de Sof-lex produziram superfícies mais lisas, livres de irregularidades, enquanto o uso de somente matrizes de poliéster permitiu uma superfície com algumas irregularidades superficiais. O sistema Enhance,associado à pasta Kota II, mostrou uma superfície com várias irregularidades profundas, com desprendimento de material. A conclusão obtida foi que o polimento das restaurações ionoméricas modifica a superfície do material restaurador.