A Review of Stem Cell Attributes Derived from the Oral Cavity.

Oral cavity stem cells (OCSCs) have been the focus of intense scientific efforts due to their accessibility and stem cell properties. The present work aims to compare the different characteristics of 6 types of dental stem cells derived from the oral cavity: dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), bone marrow mesenchymal stem cells (BMSC), and gingival mesenchymal stem cells (GMSC). Using immunofluorescence and real-time polymerase chain reaction techniques, we analysed the cells for stem cell, differentiation, adhesion, and extracellular matrix markers; the ability to proliferate in vitro; and multilineage differentiation potential. Markers such as vimentin, CD44, alkaline phosphatase, CD146, CD271, CD49f, Oct 3/4, Sox 9, FGF7, nestin, and BMP4 showed significant differences in expression levels, highlighting the heterogeneity and unique characteristics of each cell type. At the same time, we confirmed that all cell types successfully differentiated into osteogenic, chondrogenic, or adipose lineages, with different readiness. In conclusion, our study reveals the distinct properties and potential applications of various dental-derived stem cells. These findings contribute to a deeper understanding of OCSCs and their significance in future clinical applications.

Immunogenetic Background of Chronic Lymphoproliferative Disorders in Romanian Patients-Case Control Study.

BACKGROUND AND OBJECTIVES: The implications of the genetic component in the initiation and development of chronic lymphoproliferative disorders have been the subject of intense research efforts. Some of the most important genes involved in the occurrence and evolution of these pathologies are the HLA genes. The aim of this study is to analyze, for the first time, possible associations between chronic lymphoproliferative diseases and certain HLA alleles in the Romanian population. MATERIALS AND METHODS: This study included 38 patients with chronic lymphoproliferative disorders, diagnosed between 2021 and 2022 at Fundeni Clinical Institute, Bucharest, Romania, and 50 healthy controls. HLA class I and class II genes (HLA-A/B/C, HLA-DQB1/DPB1/DRB1) were investigated by doing high resolution genotyping using sequence specific primers (SSP). RESULTS: Several HLA alleles were strongly associated with chronic lymphoproliferative disorders. The most important finding was that the HLA-C*02:02 (p = 0.002, OR = 1.101), and HLA-C*12:02 (p = 0.002, OR = 1.101) have a predisposing role in the development of chronic lymphoproliferative disorders. Moreover, we identified that HLA-A*11:01 (p = 0.01, OR = 0.16), HLA-B*35:02 (p = 0.037, OR = 0.94), HLA-B*81:01 (p = 0.037, OR = 0.94), HLA-C*07:02 (p = 0.036, OR = 0.34), HLA-DRB1*11:01 (p = 0.021, OR = 0.19), and HLA-DRB1*13:02 (p = 0.037, OR = 0.94), alleles have protective roles. CONCLUSIONS: Our study indicates that HLA-C*02:02 and HLA-C*12:02 are positively associated with chronic lymphoproliferative disorders for our Romanian patients while HLA-DRB1*11:01, HLA-DRB1*13:02, and HLA-B*35:02 alleles have a protective role against these diseases.

HLA Gene Polymorphisms in Romanian Patients with Chronic Lymphocytic Leukemia.

Materials and Methods: This study included 66 patients with CLL, diagnosed between 2020 and 2022, and 100 healthy controls. HLA class I and class II genes (HLA-A/B/C, HLA-DQA1/DQB1/DPA1/DPB1, and HLA-DRB1/3/4/5) were investigated using next-generation sequencing technology. Results: Several HLA alleles were strongly associated with CLL. The most important finding was that HLA-DRB1∗04:02:01 (p=0.001, OR = 1.05) and HLA-DRB3∗02:01:01 (p=0.009, OR = 1.03) have a predisposing role in CLL development. Moreover, we identified that HLA-A∗24:02:01 0.01 (p=0.01, OR = 0.38), HLA-DQA1∗05:05:01 (p=0.01, OR = 0.56), HLA-DQB1∗03:02:01 (p=0.03, OR = 0.40), and HLA-DRB4∗01:03:01 (p=0.03, OR = 0.54 alleles have protective roles. Correlations between HLA expression and gender showed that women had a higher expression of protective HLA alleles when compared to men. Conclusions: Our data are the first to indicate that in Romanian patients with CLL, the HLA-A∗24:02:01 and HLA-DQA1∗05:05:01 alleles have a protective role against CLL development, whereas HLA-DRB1∗04:02:01 and HLA-DRB3∗02:01:01alleles are positively associated with CLL.

Molecular Analysis of HLA Genes in Romanian Patients with Chronic Hepatitis B Virus Infection.

Hepatitis B, a persistent inflammatory liver condition, stands as a significant global health issue. In Romania, the prevalence of chronic hepatitis B virus (CHB) infection ranks among the highest in the European Union. The HLA genotype significantly impacts hepatitis B virus infection progression, indicating that certain HLA variants can affect the infection's outcome. The primary goal of the present work is to identify HLA alleles and specific amino acid residues linked to hepatitis B within the Romanian population. The study enrolled 247 patients with chronic hepatitis B; HLA typing was performed using next-generation sequencing. This study's main findings include the identification of certain HLA alleles, such as DQB1*06:03:01, DRB1*13:01:01, DQB1*06:02:01, DQA1*01:03:01, DRB5*01:01:01, and DRB1*15:01:01, which exhibit a significant protective effect against HBV. Additionally, the amino acid residue alanine at DQB1_38 is associated with a protective role, while valine presence may signal an increased risk of hepatitis B. The present findings are important in addressing the urgent need for improved methods of diagnosing and managing CHB, particularly when considering the disease's presence in diverse population groups and geographical regions.

The Golgi Apparatus: A Voyage through Time, Structure, Function and Implication in Neurodegenerative Disorders.

This comprehensive review article dives deep into the Golgi apparatus, an essential organelle in cellular biology. Beginning with its discovery during the 19th century until today's recognition as an important contributor to cell function. We explore its unique organization and structure as well as its roles in protein processing, sorting, and lipid biogenesis, which play key roles in maintaining homeostasis in cellular biology. This article further explores Golgi biogenesis, exploring its intricate processes and dynamics that contribute to its formation and function. One key focus is its role in neurodegenerative diseases like Parkinson's, where changes to the structure or function of the Golgi apparatus may lead to their onset or progression, emphasizing its key importance in neuronal health. At the same time, we examine the intriguing relationship between Golgi stress and endoplasmic reticulum (ER) stress, providing insights into their interplay as two major cellular stress response pathways. Such interdependence provides a greater understanding of cellular reactions to protein misfolding and accumulation, hallmark features of many neurodegenerative diseases. In summary, this review offers an exhaustive examination of the Golgi apparatus, from its historical background to its role in health and disease. Additionally, this examination emphasizes the necessity of further research in this field in order to develop targeted therapeutic approaches for Golgi dysfunction-associated conditions. Furthermore, its exploration is an example of scientific progress while simultaneously offering hope for developing innovative treatments for neurodegenerative disorders.

Aggregation induced nucleic acids recognition by homodimeric asymmetric monomethyne cyanine fluorochromes in mesenchymal stem cells.

In the light of recent retrovirus pandemics, the issue of discovering new and diverse RNA-specific fluorochromes for research and diagnostics became of acute importance. The great majority of nucleic acid-specific probes either do not stain RNA or cannot distinguish between DNA and RNA. The versatility of polymethine dyes makes them suitable as stains for visualization, analysis, and detection of nucleic acids, proteins, and other biomolecules. We synthesized the asymmetric dicationic homodimeric monomethine cyanine dyes 1,1'-(1,3-phenylenebis(methylene))bis(4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)pyridin-1-ium) bromide (Т1) and 1,1'-(1,3-phenylenebis(methylene))bis(4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium) bromide (M1) and tested their binding specificity, spectral characteristics, membrane penetration in living and fixed cells, cellular toxicity, and stability of fluorescent emission. Mesenchymal cells have diverse phenotypes and extensive proliferation and differentiation properties. We found dyes T1 and M1 to show high photochemical stability in living mesenchymal stem cells from apical papilla (SCAP) with a strong fluorescent signal when bound to nucleic acids. We found M1 to perform better than control fluorochrome (Hoechst 33342) for in vivo DNA visualization. T1, on the other hand, stains granular cellular structures resembling ribosomes in living cells and after permeabilization of the nuclear membrane stains the nucleoli and not the chromatin in the nucleus. This makes T1 suitable for the visualization of structures rich in RNA in living and fixed cells.

The Assessment of Serum Cytokines in Oral Squamous Cell Carcinoma Patients: An Observational Prospective Controlled Study.

Background: The oral squamous cell carcinoma (OSCC) tumor microenvironment (TME) is a complex interweb of cells and mediators balancing carcinogenesis, inflammation, and the immune response. However, cytokines are not only secreted within the TME but also released by a variety of other cells that do not comprise the TME; therefore, a thorough assessment of humoral changes in OSCC should include the measurement of serum cytokines. Methods: We assessed the role of various serum cytokines in the evolution of OSCC, before and after treatment, versus a control group. We measured the serum concentrations of MIP-1α, IL-1ß, IL-4, IL-6, IL-8, IL-10, and TNF-α. Results: Significantly higher values (p < 0.01) were noted for IL-1ß, IL-6, IL-8, IL-10, and TNF-α in the OSCC group before treatment (n = 13) compared with the control group (n = 14), and the increased concentrations persisted after treatment (n = 11). Furthermore, the variations in the values of MIP-1α, IL-1ß, IL-10, and TNF-α are correlated both before and after treatment (p < 0.01). In the pretherapeutic group, IL-6 and IL-8 concentrations also correlate with IL-1ß and IL-10 serum levels (p < 0.01), while in the posttherapeutic group, IL-4 varies with MIP-1α and TNF-α (p < 0.01). Conclusion: In OSCC patients, serum cytokine levels are significantly higher compared with control, but they are not significantly altered by treatment, therefore implying that they are also influenced by systemic factors. The interactions between all involved cytokines and the various pathways they regulate warrant further studies to clarify their definitive roles.

PLGA Nanoparticles Uptake in Stem Cells from Human Exfoliated Deciduous Teeth and Oral Keratinocyte Stem Cells.

Polymeric nanoparticles have been introduced as a delivery vehicle for active compounds in a broad range of medical applications due to their biocompatibility, stability, controlled release of active compounds, and reduced toxicity. The oral route is the most used approach for delivery of biologics to the body. The homeostasis and function of oral cavity tissues are dependent on the activity of stem cells. The present work focuses, for the first time, on the interaction between two types of polymeric nanoparticles, poly (lactic-co-glycolic acid) or PLGA and PLGA/chitosan, and two stem cell populations, oral keratinocyte stem cells (OKSCs) and stem cells from human exfoliated deciduous teeth (SHEDs). The main results show that statistical significance was observed in OKSCs uptake when compared with normal keratinocytes and transit amplifying cells after 24 h of incubation with 5 and 10 µg/mL PLGA/chitosan. The CD117+ SHED subpopulation incorporated more PLGA/chitosan nanoparticles than nonseparated SHED. The uptake for PLGA/chitosan particles was better than for PLGA particles with longer incubation times, yielding better results in both cell types. The present results demonstrate that nanoparticle uptake depends on stem cell type, incubation time, particle concentration, and surface properties.

Granulocyte macrophage-colony stimulating factor and keratinocyte growth factor control of early stages of differentiation of oral epithelium.

Oral epithelial differentiation is known to be directed by underlying fibroblasts, but the responsible factor(s) have not been identified. We aimed here to identify fibroblast-derived factors responsible for oral epithelial differentiation. Primary normal human oral keratinocytes and fibroblasts were isolated from healthy volunteers after informed consent (n = 5) and 3D-organotypic (3D-OT) cultures were constructed. Various growth factors were added at a range of 0.1-100 ng/ml. 3D-OTs were harvested after ten days and assessed histologically, by immunohistochemistry and the TUNEL method. Epithelium developed in 3D-OT without fibroblasts showed an undifferentiated phenotype. Addition of granulocyte macrophage-colony stimulating factor (GM-CSF) induced expression of cytokeratin 13 in suprabasal cell layers. Admixture of GM-CSF and keratinocyte growth factor (KGF) induced, in addition, polarization of epidermal growth factor (EGF) receptor and ß1-integrin to basal cell layer and collagen IV deposition. Terminal differentiation with polarization of TUNEL-positive cells to superficial layers occurred only in the presence of fibroblasts in collagen gels either in direct contact or at distance from normal oral keratinocytes. Taken together, these results show that major aspects of oral epithelial differentiation are regulated by the synergic combination of GM-CSF and KGF. However, the terminal stage seems to be controlled by other yet unidentified fibroblast-derived diffusible factor(s).

Clinical and histopathological changes in different KIR gene profiles in chronic HCV Romanian patients.

Hepatitis C virus (HCV)-infected individuals may have a faster progression of liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC) development when influenced by host, viral and environmental factors. Hepatitis C virus disease progression is also associated with genetic variants of specific killer cell immunoglobulin-like receptors (KIRs) and genes of the major histocompatibility complex (MHC). The aim of the present study was to correlate clinical, virologic and biochemical parameters and to evaluate the possible influence of KIR genes and their HLA class I ligands in patients infected with hepatitis C virus. The present study analysed a total of 127 chronic HCV-infected patients for various biochemical and genetics factors that can influence disease progression and prognosis. Liver function parameters such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), direct bilirubin (DB), alpha-fetoprotein (AFP), HCV RNA levels and fibrosis indices were analysed using well-established biochemical methods. At the same time, KIR and HLA genotyping was performed using a polymerase chain reaction sequence-specific primer technique. Analysis of HLA class I and HLA ligands revealed that HLA-C*12:02 and HLA-A3 and HLA-A11 were positively associated with the F3-F4 fibrosis group (p = .026; OR = 8.717, CI = 1.040-73.077; respectively, p = .047; OR = 2.187; 95% CI = 1.066-4.486). KIR2DL2-positive patients had high median levels of AST after treatment and direct bilirubin levels when compared to KIR2DL2-negative patients (p = .013, respectively, p = .028). KIR2DL2/KIR2DL2-C1C1 genotype was associated with increased AST, ALT and GGT levels. A higher GGT level was also observed in KIR2DS2-C1-positive patients when compared to KIR2DS2-C1-negative patients. The present research demonstrates several links between specific clinical, virologic and biochemical parameters and the expression of KIR genes and their HLA ligands in HCV-infected patients. These connections should be taken into account when considering disease development and treatment.

HLA Alleles and KIR Genes in Romanian Patients with Chronic Hepatitis C.

BACKGROUND AND AIMS: The role of natural killer (NK) cells in the defense against hepatitis C virus (HCV) infection involve both innate and adaptive immunity. NK cells express a large panel of inhibitory and activating receptors who bind human leukocyte antigen (HLA) class I receptors. Killer cell immunoglobulin-like receptors (KIRs) are the most polymorphic of these receptors being encoded by genes distributed differently in unrelated individuals. The aim of this study was to look at the immune response in chronic HCV patients by assessing NK-KIR genes and their corresponding HLA ligands. METHODS: We genotyped 127 chronically HCV-infected patients and 130 non-infected healthy individuals for both KIR genes and their HLA ligands. The HLA-A, HLA-B, HLA-C genotypes were analyzed using polymerase chain reaction high-resolution typing. RESULTS: KIR2DL3, KIR2DL5, KIR2DS4 norm, KIR3DL3, KIR2DP1, KIR3DP1 genes were significantly increased in the HCV group compared to healthy individual. Analysis of various HLA haplotypes revealed different HLA alleles associated with increased susceptibility to HCV infection. Thus, HLA A*23:01 was more frequent in the patients' group than in the controls (p=0.030). At the same time HLA B*44:02 and C*04:02 were significantly elevated in HCV-positive patients (p=0.008 and respectively p= 0.007). CONCLUSIONS: These results suggest that the expression of KIR2DL3, KIR2DL5, KIR2DS4 norm, KIR3DL3 genes and the association with HLA alleles such as HLA A*23:01, B*44:02, C*04:02 may increase the patient susceptibility to chronic HCV infection.

Transgenerational Effects of Traumatic Historical Events on the Incidence of Metabolic Syndrome/ Nonalcoholic Fatty Liver Disease in the Romanian Population.

Concerns for successful public health management are integrated into the core business of government-responsible institutions. Diseases associated with metabolic syndrome are very common in the Romanian population. In our study, we focused on the cardiovascular and non-alcoholic fatty liver disease (NAFLD). The article starts from the hypothesis that the increased incidence of such diseases is determined today by the cumulative effect of traumatic historical events such as the famine of 1946-47 and the communist political regime specific to the 80s and 90s. This study aims to present the arguments that indicate the correlation of economic variables whose variation can be easily determined by traumatic events that affected the economy, with variables able to measure the incidence of various diseases usually associated with metabolic syndrome or NAFLD. A series of statistical data were analyzed from the official sources available in the form of consecutive value data for the 1995-2018 period. The results highlighted a direct and strong link between the variable gross domestic product (GDP) per capita in USD, 2011 purchasing power parity (PPP) and specific incidence of circulatory, nutritional endocrine and metabolic diseases, as well as a strong and inverse link between GDP and infant's deaths per 1000 live births. Conclusions highlight that the effects of traumatic historical events must be made aware through medical education of the population, supporting the idea according to which the incidence of various metabolic diseases is greater for the offspring of those who have actively suffered during such events.

Interaction between a 3D collagen matrix used for periodontal soft tissue regeneration and T-lymphocytes: An in vitro pilot study.

Previous experimental models showed that activation of the immune system, particularly T cells, is required for optimal healing following wounds or surgery in the oral cavity. Therefore, studies to explore the interactions between the immune system and the collagen matrix are mandated. The specific aim of the present study was to analyze the interactions between T lymphocytes and a resorbable three-dimensional (3D) collagen matrix routinely used for soft tissue regeneration during periodontal surgery. Peripheral venous blood samples were collected from five patients. Following Ficoll-Paque separation, mononuclear cells were grown on fully resorbable 3D collagen matrices for 5 days. Lymphocytes were analyzed by flow cytometry for different surface markers, including CD4, CD8, CD38 and CD69. Cell viability and late apoptosis/necrosis were assessed in each group using an apoptosis assay based on Annexin V/propidium iodide staining. After 5 days in contact with the collagen matrix, the T cells expressed different surface markers. The overall T cell population increased significantly in the collagen matrix group compared to the respective controls (31.9±6.5 vs. 38.7±3.8%). CD8 and CD69 also increased significantly compared to their controls (CD69: 19.7±3.0 vs. 27.1±4.5% for collagen vs. control groups). At the same time, CD4 and CD38 expression was similar in both groups. Viability and apoptosis/necrosis were also identical in the samples and controls. These results show that the interaction between the collagen matrix and the immune cells stimulated activation of T cells and did not impair the healing process.

Salivary biomarkers of inflammation in systemic lupus erythematosus.

Saliva is currently used as a reliable diagnostic fluid in a wide range of local and systemic diseases. However, the link between salivary diagnosis and the inflammatory process in autoimmune diseases has not yet been explored. The aim of our study is to assess possible correlations between salivary inflammatory markers and systemic lupus erythematosus (SLE). Patients fulfilling the Systemic Lupus International Collaborating Clinics (SLICC) diagnosis criteria were included. Salivary and serum levels of interleukin-6 (IL-6), leptin, monocyte chemoattractant protein-1 (MCP-1) and plasminogen activator inhibitor-1 (PAI-1) were determined using stochastic sensors. Serum leptin and IL-6 had significantly higher levels in SLE patients compared to non-SLE. Also, salivary IL-6 levels highly correlated with the serum IL-6 levels. A positive correlation was found between salivary and serum levels of IL-6, signaling salivary IL-6 as a reliable marker for assessing the inflammation process in SLE.

Histology and surface ultrastructure during early healing after gingival augmentation with a three-dimensional collagen matrix: A report of six cases.

OBJECTIVES: The objective of the present case series is to describe the histology and surface ultrastructure of augmented keratinized gingival mucosa in humans during the early healing phase after surgical placement of a xenogeneic collagen matrix. METHOD AND MATERIALS: Six patients underwent surgical augmentation of keratinized tissue by placement of a three-dimensional (3D) xenogeneic collagen matrix. Full-depth mucosal biopsies including original attached gingiva, augmented gingiva, and the separation zone were performed at baseline and at postoperative days 7 and 14. The specimens were stained with hematoxylin-eosin, Masson-trichrome, picrosirius red, and Papanicolaou's trichrome. Low-vacuum scanning electron microscopy (SEM) surface analysis was correlated with histology. RESULTS: The separation zone was clearly visible upon histologic and SEM examination at 7 days. The portions of augmented mucosa consisted of well-structured, immature gingival tissue with characteristics of per secundam healing underlying a completely detached amorphous collagenous membrane-like structure of approximately 100 µm thick. At 14 days, histologic and ultrastructural examinations showed an almost complete maturation process. There were no detectable remnants of the collagen matrix within the newly formed tissues at either time point. CONCLUSIONS: Within their limits the results suggest that the 3D collagen matrix appears to play an indirect role during the early phase of wound healing by protecting the newly formed underlying tissue and guiding the epithelialization process.

From Normal Skin to Squamous Cell Carcinoma: A Quest for Novel Biomarkers.

Squamous cells carcinoma (SCC) is the second most frequent of the keratinocyte-derived malignancies after basal cell carcinoma and is associated with a significant psychosocial and economic burden for both the patient himself and society. Reported risk factors for the malignant transformation of keratinocytes and development of SCC include ultraviolet light exposure, followed by chronic scarring and inflammation, exposure to chemical compounds (arsenic, insecticides, and pesticides), and immune-suppression. Despite various available treatment methods and recent advances in noninvasive or minimal invasive diagnostic techniques, the risk recurrence and metastasis are far from being negligible, even in patients with negative histological margins and lymph nodes. Analyzing normal, dysplastic, and malignant keratinocyte proteome holds special promise for novel biomarker discovery in SCC that could be used in the future for early detection, risk assessment, tumor monitoring, and development of targeted therapeutic strategies.

Gene Expression and Proteome Analysis as Sources of Biomarkers in Basal Cell Carcinoma.

Basal cell carcinoma (BCC) is the world's leading skin cancer in terms of frequency at the moment and its incidence continues to rise each year, leading to profound negative psychosocial and economic consequences. UV exposure is the most important environmental factor in the development of BCC in genetically predisposed individuals, this being reflected by the anatomical distribution of lesions mainly on sun-exposed skin areas. Early diagnosis and prompt management are of crucial importance in order to prevent local tissue destruction and subsequent disfigurement. Although various noninvasive or minimal invasive techniques have demonstrated their utility in increasing diagnostic accuracy of BCC and progress has been made in its treatment options, recurrent, aggressive, and metastatic variants of BCC still pose significant challenge for the healthcare system. Analysis of gene expression and proteomic profiling of tumor cells and of tumoral microenvironment in various tissues strongly suggests that certain molecules involved in skin cancer pathogenic pathways might represent novel predictive and prognostic biomarkers in BCC.

Evaluation of oral keratinocyte progenitor and T-lymphocite cells response during early healing after augmentation of keratinized gingiva with a 3D collagen matrix - a pilot study.

BACKGROUND: The aim of the present study is to analyze the behavior of selected populations of oral keratinocytes and T-lymphocytes, responsible for re-constructing and maintaining the oral epithelial tissue architecture, following augmentation of the keratinized oral mucosa using a 3D-collagen matrix. METHODS: Different groups of oral keratinocytes were isolated from biopsies harvested from 3 patients before the surgical procedure, as well as 7 and 14 days after the augmentation procedure. T-lymphocytes were isolated from peripheral blood at same timepoints. Keratinocytes were characterized for stem and differentiation markers, such as p63, cytokeratin 10 and 14, and in vitro parameters, such as cell viability, cell size and colony-forming efficiency. T-lymphocytes were analyzed for viability and the expression of various cluster of differentiation markers. The methods included magnetic separation of cell populations, immunofluorescence, flow cytometry, and histology of oral biopsies. RESULTS: Both at 7 and 14 days, the majority of cells that repopulate the matrix were actively proliferating/progenitor oral keratinocytes with the phenotype integrin alfa6beta4 + CD71+. These cells display in vitro characteristics similar to the progenitor cells analyzed before the matrix placement. T-lymphocytes expressed CD8 and CD69 markers, while CD25 was absent. CONCLUSION: The study shows that two weeks after the collagen membrane placement, the healing process appeared to be histologically complete, with no abnormal immune response induced by the matrix, however, with a higher than usual content of active proliferating cells, the majority of keratinocytes being characterized as transit amplifying cells.

Organic Nanomaterials and Their Applications in the Treatment of Oral Diseases.

There is a growing interest in the development of organic nanomaterials for biomedical applications. An increasing number of studies focus on the uses of nanomaterials with organic structure for regeneration of bone, cartilage, skin or dental tissues. Solid evidence has been found for several advantages of using natural or synthetic organic nanostructures in a wide variety of dental fields, from implantology, endodontics, and periodontics, to regenerative dentistry and wound healing. Most of the research is concentrated on nanoforms of chitosan, silk fibroin, synthetic polymers or their combinations, but new nanocomposites are constantly being developed. The present work reviews in detail current research on organic nanoparticles and their potential applications in the dental field.

Hydrogen Sulfide, Oxidative Stress and Periodontal Diseases: A Concise Review.

In the past years, biomedical research has recognized hydrogen sulfide (H2S) not only as an environmental pollutant but also, along with nitric oxide and carbon monoxide, as an important biological gastransmitter with paramount roles in health and disease. Current research focuses on several aspects of H2S biology such as the biochemical pathways that generate the compound and its functions in human pathology or drug synthesis that block or stimulate its biosynthesis. The present work addresses the knowledge we have to date on H2S production and its biological roles in the general human environment with a special focus on the oral cavity and its involvement in the initiation and development of periodontal diseases.