Study on the Restoration of Class II Carious Cavities by Virtual Methods: Simulation of Mechanical Behavior.

The restoration of class II cavities is predominantly carried out with composite materials. Due to the high failure rate in restoring this type of cavity, composite materials with much-improved properties and new application techniques have been promoted. The study aimed to analyze the mechanical behavior of several topical composite materials (nanocomposites, nanohybrids and ormocer) using different application techniques. In a lower second molar, a class II occlusal cavity was prepared. As filling materials, we used the following combinations: Admira Fusion and Admira Fusion Flow, Grandio and Grandio Flow, Filtek Supreme XT and Filtek Supreme Flow. These were applied using a snow plow, injection molded and Bichacho techniques. Three-dimensional scanning of the molar with the prepared cavity was performed, and then scanning of each layer of added composite material was performed, obtaining three-dimensional models. The virtual molar models were analyzed with software specific to the finite element analysis method, where their physical-mechanical properties were entered and assigned to the components of the virtual molar. Simulations at high forces specific to bruxism were then carried out and analyzed, and compared. The values of displacements and strain, for all six analyzed situations, are relatively small (range from 5.25 × 10-6-3.21 × 10-5 for displacement, 6.22 × 10-3-4.34 × 10-3 for strain), which validates all three methods and the materials used. As far as the stress values are concerned, they are similar for all methods (250-300 MPa), except for the snow plow and injection-molded techniques using Grandio and Grandio Flow composites, where the maximum von Mises stress value was more than double (approximately 700 MPa). When using the combination of Grandio and Grandio Flow materials, the 1 mm thickness of the fluid composite layer was found to have a major influence on occlusal forces damping as opposed to 0.5 mm. Therefore, the Bichacho technique is indicated at the expense of the snow plow and injection-molded techniques. The composite materials used by us in this study are state-of-the-art, with clear indications for restoring cavities resulting from the treatment of carious lesions. However, their association and application technique in the case of Class II cavities is of clinical importance for resistance to masticatory forces.

Involvement of TLR9 in priming the immune response in oral papillomatosis induced by low-risk HPV.

Oral papillomatosis represents a benign lesion of the oral mucosa often induced by human papillomavirus (HPV) or having a non-infection local or general etiology. HPVs are very well adapted and efficient viruses able to produce changes in the immune system, endowed with the ability to replicate in the keratinocytes and to remain silent. The natural evolution of HPV infection is different, depending on the efficiency of the innate immune system. The purpose of this study was to explore Toll-like receptor 9 (TLR9) immunohistochemical expression in low-risk (LR)-HPV oral infection and its ability to facilitate an efficient immune response by activating the macrophages, which serve as main antigen-presenting cells. Samples of two groups of oral mucosae - LR-HPV-positive and HPV-negative - were processed for immunohistochemistry technique and incubated with antibody against TLR9 and cluster of differentiation 68 (CD68). Image analysis and morphometry were conducted to assess the intensity of TLR9 immune signal in the epithelium and the number of macrophages labeled by CD68. We found a statistically significant difference between macrophage count for the subjects in HPV-positive and HPV-negative groups; thought no significant differences of TLR9 immune signal was noted, which demonstrates a diminished immune response in HPV-positive group, probably influencing the time of lesion's clearance.

Oral Papillomatosis: Its Relation with Human Papilloma Virus Infection and Local Immunity-An Update.

Oral papilloma lesions may appear as a result of HPV infection, or not, and only special molecular methods could differentiate them. Low-risk and high-risk HPV types could induce oral HPV papillomatosis with different natural evolution, clearance and persistence mechanisms. The pathogenic mechanisms are based on the crosstalk between the oral epithelial and immune cells and this very efficient virus. HPV acts as a direct inducer in the process of transforming a benign lesion into a malignant one, the cancerization process being also debated in this paper. According to the degree of malignity, three types of papillomatous lesions can be described in the oral cavity: benign lesions, potential malign disorders and malignant lesions. The precise molecular diagnostic is important to identify the presence of various virus types and also the virus products responsible for its oncogenicity. An accurate diagnostic of oral papilloma can be established through a good knowledge of etiological and epidemiological factors, clinical examination and laboratory tests. This review intends to update the pathogenic mechanisms driving the macroscopic and histological features of oral papillomatosis having HPV infection as the main etiological factor, focusing on its interreference in the local immunity. In the absence of an accurate molecular diagnostic and knowledge of local immunological conditions, the therapeutic strategy could be difficult to decide.

Long Noncoding RNA FENDRR Inhibits Lung Fibroblast Proliferation via a Reduction of ß-Catenin.

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and usually lethal lung disease and it has been widely accepted that fibroblast proliferation is one of the key characteristics of IPF. Long noncoding RNAs (lncRNAs) play vital roles in the pathogenesis of many diseases. In this study, we investigated the role of lncRNA FENDRR on fibroblast proliferation. Human lung fibroblasts stably overexpressing FENDRR showed a reduced cell proliferation compared to those expressing the control vector. On the other hand, FENDRR silencing increased fibroblast proliferation. FENDRR bound serine-arginine rich splicing factor 9 (SRSF9) and inhibited the phosphorylation of p70 ribosomal S6 kinase 1 (PS6K), a downstream protein of the mammalian target of rapamycin (mTOR) signaling. Silencing SRSF9 reduced fibroblast proliferation. FENDRR reduced ß-catenin protein, but not mRNA levels. The reduction of ß-catenin protein levels in lung fibroblasts by gene silencing or chemical inhibitor decreased fibroblast proliferation. Adenovirus-mediated FENDRR transfer to the lungs of mice reduced asbestos-induced fibrotic lesions and collagen deposition. RNA sequencing of lung tissues identified 7 cell proliferation-related genes that were up-regulated by asbestos but reversed by FENDRR. In conclusion, FENDRR inhibits fibroblast proliferation and functions as an anti-fibrotic lncRNA.

LncRNA FENDRR Expression Correlates with Tumor Immunogenicity.

FENDRR (Fetal-lethal non-coding developmental regulatory RNA, LncRNA FOXF1-AS1) is a recently identified tumor suppressor long non-coding (LncRNA) RNA, and its expression has been linked with epigenetic modulation of the target genes involved in tumor immunity. In this study, we aimed to understand the role of FENDRR in predicting immune-responsiveness and the inflammatory tumor environment. Briefly, FENDRR expression and its relationship to immune activation signals were assessed in murine cell lines. Data suggested that tumor cells (e.g., C26 colon, 4T1 breast) that typically upregulate immune activation genes and the MHC class I molecule exhibited high FENDRR expression levels. Conversely, tumor cells with a generalized downregulation of immune-related gene expression (e.g., B16F10 melanoma) demonstrated low to undetectable FENDRR levels. Mechanistically, the modulation of FENDRR expression enhanced the inflammatory and WNT signaling pathways in tumors. Our early data suggest that FENDRR can play an important role in the development of immune-relevant phenotypes in tumors, and thereby improve cancer immunotherapy.

Xylosyltransferase 2 deficiency and organ homeostasis.

In this paper we characterize the function of Xylosyltransferase 2 (XylT2) in different tissues to investigate the role XylT2 has in the proteoglycan (PG) biochemistry of multiple organs. The results show that in all organs examined there is a widespread and significant decrease in total XylT activity in Xylt2 knock out mice (Xylt2-/-). This decrease results in increased organ weight differences in lung, heart, and spleen. These findings, in addition to our previous findings of increased liver and kidney weight with loss of serum XylT activity, suggest systemic changes in organ function due to loss of XylT2 activity. The Xylt2-/- mice have splenomegaly due to enlargement of the red pulp area and enhanced pulmonary response to bacterial liposaccharide. Tissue glycosaminoglycan composition changes are also found. These results demonstrate a role of XylT2 activity in multiple organs and their PG content. Because the residual XylT activity in the Xylt2-/- is due to xylosyltransferase 1 (XylT1), these studies indicate that both XylT1 and XylT2 have important roles in PG biosynthesis and organ homeostasis.

Long non-coding RNA FENDRR regulates IFNγ-induced M1 phenotype in macrophages.

Macrophages play an essential role in host defense and display remarkable plasticity in switching between classically (pro-inflammatory-M1) and alternatively activated (anti-inflammatory-M2) phenotypes. The molecular mechanisms of macrophage polarization are not fully understood. Long non-coding RNAs (lncRNAs) with a length of > 200 nucleotides have been shown to play diverse roles in biological processes. Aberrant expression of lncRNAs is associated with a variety of pathophysiological conditions such as cancer, diabetes, cardiovascular, pulmonary diseases, and tissue fibrosis. In this study, we investigated the role of lncRNA FENDRR in human and mouse macrophage polarization. Human THP-1 monocytes were activated with phorbol-12-myristate-13-acetate (PMA) and differentiated into M1 macrophages with IFNγ or M2 macrophages with IL4. Real-time PCR analysis revealed that FENDRR was expressed 80-fold higher in M1 macrophages than that in M2 macrophages. Overexpression of FENDRR in PMA-activated THP-1 cells increased the IFNγ-induced expression of M1 markers, including IL1ß and TNFα at both mRNA and protein levels. Knockdown of FENDRR had an opposite effect. Similarly, FENDRR overexpression in primary mouse bone marrow-derived macrophages increased mRNA expression of M1 markers. FENDRR overexpression increased, while FENDRR knock-down decreased, the IFNγ-induced phosphorylation of STAT1 in PMA-activated THP-1 cells. Our studies suggest that FENDRR enhances IFNγ-induced M1 macrophage polarization via the STAT1 pathway.

Immunophenotypical alterations with impact on the epithelial-mesenchymal transition (EMT) process in salivary gland adenoid cystic carcinomas.

Adenoid cystic carcinoma (ACC) is one of the most common malignant salivary glands neoplasms with an indolent clinical course, slow-growing but locally aggressive and quite often with delayed recurrence and distant metastasis. In order to elucidate this tumoral behavior, we conducted an immunohistochemical study investigating the alterations of epithelial phenotype with anti-cytokeratin (CK) AE1∕AE3 and anti-E-cadherin antibodies, and the acquisition of mesenchymal phenotype with vimentin, fibronectin, N-cadherin and P-cadherin in salivary ACCs. Thus, we recorded a reduction of CK AE1∕AE3, E-cadherin, P-cadherin and fibronectin reactivity in the solid variant and especially in the cells from the periphery of invasive neoplastic proliferations, regardless histological type. These phenotypical alterations suggest the involvement of the epithelial-mesenchymal transition (EMT) process in the progression of salivary ACCs.

The immunophenotype of epithelial to mesenchymal transition inducing transcription factors in salivary gland adenoid cystic carcinomas.

Adenoid cystic carcinoma (ACC) is the second most common malignant salivary glands neoplasms with a controversial biological behavior. Even though these tumors grow slowly, they have increased potential for recurrence and distant metastasis. In order to elucidate this behavior, our study aimed to investigate the immunoexpression in such tumors of the most important transcriptional factors [Twist, Snail, Slug, and zinc finger E-box binding homeobox 1 (ZEB1)] involved in the epithelial-mesenchymal transition process. The highest level of expression was recorded for Twist, present in all the investigated cases, followed by the Slug and Snail, while no tumor parenchyma reactivity was noticed for the ZEB1 factor. There were tumor reactivity differences regarding topography, histopathological variant, and nerve and lymph node invasion status. Thus, tumors developed from the intraoral minor salivary glands, with solid pattern, perineural invasion, locally aggressive and with lymph node metastasis were the most reactive. Therefore, these transcription factors could be useful as prognostic biomarkers and efficient therapeutic targets in such salivary malignancies.

Adipose tissue loss and lipodystrophy in xylosyltransferase II deficient mice.

BACKGROUND/OBJECTIVES: The cellular and extracellular matrix (ECM) interactions that regulate adipose tissue homeostasis are incompletely understood. Proteoglycans (PGs) and their sulfated glycosaminoglycans (GAGs) provide spatial and temporal signals for ECM organization and interactions with resident cells by impacting growth factor and cytokine activity. Therefore, PGs and their GAGs could be significant to adipose tissue homeostasis. The purpose of this study was to determine the role of ECM sulfated GAGs in adipose tissue homeostasis. METHODS: Adipose tissue and metabolic homeostasis in mice deficient in xylosyltransferase 2 (Xylt2-/-) were examined by histologic analyses, gene expression analyses, whole body fat composition measurements, and glucose tolerance test. Adipose tissue inflammation and adipocyte precursors were characterized by flow cytometry and in vitro culture of mesenchymal stem cells. RESULTS: Xylt2-/- mice have low body weight due to overall reductions in abdominal fat deposition. Histologically, the adipocytes are reduced in size and number in both gonadal and mesenteric fat depots of Xylt2-/- mice. In addition, these mice are glucose intolerant, insulin resistant, and have increased serum triglycerides as compared to Xylt2 + / + control mice. Furthermore, the adipose tissue niche has increased inflammatory cells and enrichment of proinflammatory factors IL6 and IL1ß, and these mice also have a loss of adipose tissue vascular endothelial cells. Lastly, xylosyltransferease-2 (XylT2) deficient mesenchymal stem cells from gonadal adipose tissue and bone marrow exhibit impaired adipogenic differentiation in vitro. CONCLUSIONS: Decreased GAGs due to the loss of the key GAG assembly enzyme XylT2 causes reduced steady state adipose tissue stores leading to a unique lipodystrophic model. Accumulation of an adipocytic precursor pool of cells is discovered indicating an interruption in differentiation. Therefore, adipose tissue GAGs are important in the homeostasis of adipose tissue by mediating control of adipose precursor development, tissue inflammation, and vascular development.

Chemo-immunotherapy of colon cancer with focused ultrasound and Salmonella-laden temperature sensitive liposomes (thermobots).

Using attenuated Salmonella that efficiently homes in solid tumors, here we developed thermobots that actively transported membrane attached low-temperature sensitive liposome (LTSL) inside colon cancer cells for triggered doxorubicin release and simultaneous polarized macrophages to M1 phenotype with high intensity focused ultrasound (HIFU) heating (40-42 °C). Biocompatibility studies showed that the synthesized thermobots were highly efficient in LTSL loading without impacting its viability. Thermobots demonstrated efficient intracellular trafficking, high nuclear localization of doxorubicin, and induced pro-inflammatory cytokine expression in colon cancer cells in vitro. Combination of thermobots and HIFU heating (~30 min) in murine colon tumors significantly enhanced polarization of macrophages to M1 phenotype and therapeutic efficacy in vivo compared to control. Our data suggest that the thermobots and focused ultrasound treatments have the potential to improve colon cancer therapy.

Hypoxia induces pulmonary fibroblast proliferation through NFAT signaling.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive and typically fatal lung disease with a very low survival rate. Excess accumulation of fibroblasts, myofibroblasts and extracellular matrix creates hypoxic conditions within the lungs, causing asphyxiation. Hypoxia is, therefore, one of the prominent features of IPF. However, there have been few studies concerning the effects of hypoxia on pulmonary fibroblasts. In this study, we investigated the molecular mechanisms of hypoxia-induced lung fibroblast proliferation. Hypoxia increased the proliferation of normal human pulmonary fibroblasts and IPF fibroblasts after exposure for 3-6 days. Cell cycle analysis demonstrated that hypoxia promoted the G1/S phase transition. Hypoxia downregulated cyclin D1 and A2 levels, while it upregulated cyclin E1 protein levels. However, hypoxia had no effect on the protein expression levels of cyclin-dependent kinase 2, 4, and 6. Chemical inhibition of hypoxia-inducible factor (HIF)-2 reduced hypoxia-induced fibroblast proliferation. Moreover, silencing of Nuclear Factor Activated T cell (NFAT) c2 attenuated the hypoxia-mediated fibroblasts proliferation. Hypoxia also induced the nuclear translocation of NFATc2, as determined by immunofluorescence staining. NFAT reporter assays showed that hypoxia-induced NFAT signaling activation is dependent on HIF-2, but not HIF-1. Furthermore, the inhibition or silencing of HIF-2, but not HIF-1, reduced the hypoxia-mediated NFATc2 nuclear translocation. Our studies suggest that hypoxia induces the proliferation of human pulmonary fibroblasts through NFAT signaling and HIF-2.

Parotid sclerosing mucoepidermoid carcinoma: a case report and immunohistochemical study.

Here we report the case of a 63-year-old female with a parotid sclerosing mucoepidermoid carcinoma diagnosed and treated at the Department of Oral and Maxillofacial Surgery, Emergency County Hospital of Craiova, Romania. The clinical and imaging investigation revealed a parotid malignant tumor with central fluid-filled cystic formation. Histopathology found an intermediate grade sclerosing mucoepidermoid carcinoma that invaded the adjacent adipose and striated muscle tissues, but without perineural and lymphovascular invasion. The immunohistochemistry investigated mainly biomarkers involved in the induction of a local aggressive behavior. This case report describes a rare parotid sclerosing mucoepidermoid carcinoma with peculiar clinical and morphological characteristic features. The immunohistochemical study sustained its intermediate grade malignancy highlighting the prognostic value of some of the used biomarkers.

RAGE and TGF-ß1 Cross-Talk Regulate Extracellular Matrix Turnover and Cytokine Synthesis in AGEs Exposed Fibroblast Cells.

AGEs accumulation in the skin affects extracellular matrix (ECM) turnover and triggers diabetes associated skin conditions and accelerated skin aging. The receptor of AGEs (RAGE) has an essential contribution to cellular dysfunction driven by chronic inflammatory responses while TGF-ß1 is critical in both dermal homeostasis and inflammation. We investigated the contribution of RAGE and TGF-ß1 to the modulation of inflammatory response and ECM turnover in AGEs milieu, using a normal fibroblast cell line. RAGE, TGF-ß1, collagen I and III gene and protein expression were upregulated after exposure to AGEs-BSA, and MMP-2 was activated. AGEs-RAGE was pivotal in NF-κB dependent collagen I expression and joined with TGF-ß1 to stimulate collagen III expression, probably via ERK1/2 signaling. AGEs-RAGE axis induced upregulation of TGF-ß1, TNF-α and IL-8 cytokines. TNF-α and IL-8 were subjected to TGF-ß1 negative regulation. RAGE's proinflammatory signaling also antagonized AGEs-TGF-ß1 induced fibroblast contraction, suggesting the existence of an inhibitory cross-talk mechanism between TGF-ß1 and RAGE signaling. RAGE and TGF-ß1 stimulated anti-inflammatory cytokines IL-2 and IL-4 expression. GM-CSF and IL-6 expression appeared to be dependent only on TGF-ß1 signaling. Our data also indicated that IFN-γ upregulated in AGEs-BSA milieu in a RAGE and TGF-ß1 independent mechanism. Our findings raise the possibility that RAGE and TGF-ß1 are both involved in fibrosis development in a complex cross-talk mechanism, while also acting on their own individual targets. This study contributes to the understanding of impaired wound healing associated with diabetes complications.

Homozygosity for frameshift mutations in XYLT2 result in a spondylo-ocular syndrome with bone fragility, cataracts, and hearing defects.

Heparan and chondroitin/dermatan sulfated proteoglycans have a wide range of roles in cellular and tissue homeostasis including growth factor function, morphogen gradient formation, and co-receptor activity. Proteoglycan assembly initiates with a xylose monosaccharide covalently attached by either xylosyltransferase I or II. Three individuals from two families were found that exhibited similar phenotypes. The index case subjects were two brothers, individuals 1 and 2, who presented with osteoporosis, cataracts, sensorineural hearing loss, and mild learning defects. Whole exome sequence analyses showed that both individuals had a homozygous c.692dup mutation (GenBank: NM_022167.3) in the xylosyltransferase II locus (XYLT2) (MIM: 608125), causing reduced XYLT2 mRNA and low circulating xylosyltransferase (XylT) activity. In an unrelated boy (individual 3) from the second family, we noted low serum XylT activity. Sanger sequencing of XYLT2 in this individual revealed a c.520del mutation in exon 2 that resulted in a frameshift and premature stop codon (p.Ala174Profs(∗)35). Fibroblasts from individuals 1 and 2 showed a range of defects including reduced XylT activity, GAG incorporation of (35)SO4, and heparan sulfate proteoglycan assembly. These studies demonstrate that human XylT2 deficiency results in vertebral compression fractures, sensorineural hearing loss, eye defects, and heart defects, a phenotype that is similar to the autosomal-recessive disorder spondylo-ocular syndrome of unknown cause. This phenotype is different from what has been reported in individuals with other linker enzyme deficiencies. These studies illustrate that the cells of the lens, retina, heart muscle, inner ear, and bone are dependent on XylT2 for proteoglycan assembly in humans.

Heterogeneity of collagen secreting cells in gingival fibrosis--an immunohistochemical assessment and a review of the literature.

AIM: In this work, we compared the histological features of the gingival lesions clinically diagnosed as fibrotic overgrowths due to various etiologic factors as well as an immunohistochemical assessment of fibroblasts phenotypic heterogeneity using the specific labeling for vimentin, α-smooth muscle actin (α-SMA) and fibroblast specific protein-1 (FSP1). MATERIALS AND METHODS: Tissue samples were obtained from 12 patients clinically diagnosed with fibrotic gingival overgrowth, divided in four groups. Fragments of gingiva were processed for paraffin embedding. Serial sections were used for routine staining Hematoxylin-Eosin, trichromic Masson and Goldner-Szekely, and for immunohistochemical reactions to label vimentin, α-SMA and FSP1 using for signal amplification several techniques (EnVision, LSAB, ABC). RESULTS: Storage of collagen fibers, increase of fibroblast number and frequent presence of inflammatory infiltrate are histological issues of all fibrotic gingival overgrowth. The incidence of granulation tissue varies but the frequency of its presence point the attention to the involvement in collagen metabolism imbalance. Immunostaining for vimentin showed a difference between its expression in samples from different groups. Except the cases of fibrosis induced by orthodontic devices, cells positive for α-SMA were rare. FSP1-positive fibroblasts were the most frequent in all cases from all the groups selected for this study. CONCLUSIONS: The phenotype of fibroblasts is different in gingival fibrosis in relation to the risk factor, at present the most common being vimentin-positive and FSP1-positive fibroblasts. Myofibroblasts are rare in gingival fibrosis, the most numerous being in local lesions caused by wearing orthodontic devices and in syndromic fibromatosis. Further studies are required to elucidate the manner in which the active fibroblasts are recruited in relation to the etiologic factor of gingival overgrowth.

Extracellular matrix is modulated in advanced glycation end products milieu via a RAGE receptor dependent pathway boosted by transforming growth factor-ß1 RAGE.

BACKGROUND: Interstitial fibrosis is induced by imbalances in extracellular matrix homeostasis. Advanced glycation end products (AGEs) can bind and activate the receptor for AGEs (RAGE), which is involved in diabetic nephropathy. We set out to identify the role of AGEs in producing alterations leading to matrix hypertrophy and the pathway through which aminoguanidine, as well as anti-RAGE and anti-transforming growth factor (TGF)-ß1 antibody treatments could prevent these modifications. METHODS: Human embryonic kidney (HEK-293) cells were exposed to glycated bovine serum albumin (AGE-BSA) and co-treated with neutralizing antibodies or aminoguanidine. The effects on the transcriptional and translational levels of RAGE, TGF-ß1 and collagen IV were evaluated, while metalloproteinase activity was assessed by gelatin zymography. RESULTS: AGE-BSA (200 µg/mL) upregulated RAGE's expression, while TGF-ß1 synthesis and the formation of its bioactive form were increased in a dose-dependent manner by AGEs. AGE-BSA exposure increased both matrix metalloproteinase (MMP) activity and collagen IV synthesis, boosted by TGF-ß1 upregulation. Aminoguanidine's effects revealed that small concentrations (10 µmol/L) enhance AGE-BSA effects, by increasing the expression of RAGE and TGF-ß1, while higher concentrations (100 µmol/L) contribute to their downregulation. CONCLUSIONS: Although AGEs regulate RAGE and TGF-ß1 by distinct pathways, RAGE activation leads to a further increase of TGF-ß1 levels. MMP-2 activity seems to rely on TGF-ß1, while MMP-9 was dependent on RAGE. These factors converge to control collagen IV turnover. Furthermore, although the antibody treatments might appear more efficient than AG in decreasing collagen IV levels, the cells compensate the RAGE and TGF-ß1 blockade by increasing the mRNA expression of these proteins.

Acinic cell carcinoma of the salivary glands: an immunohistochemical study of angiogenesis in 12 cases.

Acinic cell carcinoma (ACC) is the third most common epithelial malignancy of the salivary glands in adults, exhibiting a low-grade malignancy that mainly occurs in the parotid gland and at a relatively younger age than other salivary gland tumors. We performed an immunohistochemically study regarding angiogenesis in ACC, by assessing the CD105+ tumor microvessels density and investigating the VEGF and its receptors VEGFR1 and VEGFR2 expression in tumor samples. The results indicated an active angiogenesis in ACC, with the highest CD105-MVD score recorded in the solid variant. This fact was supported by the reactivity of tumor cells and endothelial blood vessel cells for VEGF and its receptors (VEGFR1 and VEGFR2). Thus, we concluded that in ACC do exist autocrine and paracrine VEGF loops implicated in growth and progression of this kind of salivary gland tumors.

Interaction of silicon-based quantum dots with gibel carp liver: oxidative and structural modifications.

Quantum dots (QDs) interaction with living organisms is of central interest due to their various biological and medical applications. One of the most important mechanisms proposed for various silicon nanoparticle-mediated toxicity is oxidative stress. We investigated the basic processes of cellular damage by oxidative stress and tissue injury following QD accumulation in the gibel carp liver after intraperitoneal injection of a single dose of 2 mg/kg body weight Si/SiO2 QDs after 1, 3, and 7 days from their administration.QDs gradual accumulation was highlighted by fluorescence microscopy, and subsequent histological changes in the hepatic tissue were noted. After 1 and 3 days, QD-treated fish showed an increased number of macrophage clusters and fibrosis, while hepatocyte basophilia and isolated hepatolytic microlesions were observed only after substantial QDs accumulation in the liver parenchyma, at 7 days after IP injection.Induction of oxidative stress in fish liver was revealed by the formation of malondialdehyde and advanced oxidation protein products, as well as a decrease in protein thiol groups and reduced glutathione levels. The liver enzymatic antioxidant defense was modulated to maintain the redox status in response to the changes initiated by Si/SiO2 QDs. So, catalase and glutathione peroxidase activities were upregulated starting from the first day after injection, while the activity of superoxide dismutase increased only after 7 days. The oxidative damage that still occurred may impair the activity of more sensitive enzymes. A significant inhibition in glucose-6-phosphate dehydrogenase and glutathione-S-transferase activity was noted, while glutathione reductase remained unaltered.Taking into account that the reduced glutathione level had a deep decline and the level of lipid peroxidation products remained highly increased in the time interval we studied, it appears that the liver antioxidant defense of Carassius gibelio does not counteract the oxidative stress induced 7 days after silicon-based QDs exposure in an efficient manner.

Structural and oxidative changes in the kidney of crucian carp induced by silicon-based quantum dots.

Silicon-based quantum dots were intraperitoneally injected in Carassius auratus gibelio specimens and, over one week, the effects on renal tissue were investigated by following their distribution and histological effects, as well as antioxidative system modifications. After three and seven days, detached epithelial cells from the basal lamina, dilated tubules and debris in the lumen of tubules were observed. At day 7, nephrogenesis was noticed. The reduced glutathione (GSH) concentration decreased in the first three days and started to rise later on. The superoxide dismutase (SOD) activity increased only after one week, whereas catalase (CAT) was up-regulated in a time-dependent manner. The activities of glutathione reductase (GR) and glutathione peroxidise (GPX) decreased dramatically by approximately 50% compared to control, whereas the glutathione-S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) increased significantly after 3 and 7 days of treatment. Oxidative modifications of proteins and the time-dependent increase of Hsp70 expression were also registered. Our data suggest that silicon-based quantum dots induced oxidative stress followed by structural damages. However, renal tissue is capable of restoring its integrity by nephron development.