Bone grafting materials in dentoalveolar reconstruction: A comprehensive review.

Bone deficits of the jaws are often attributed to accidents, surgical removal of benign lesions or malignant neoplasms, congenital abnormalities, periodontal inflammation, tooth abscess or extraction and finally jaw atrophy due to advanced age or general disease. These bone defects require rehabilitation for a variety of reasons, e.g. maintaining the normal anatomic outline, eliminating empty space, aesthetic restoration and placing dental implants. Today, several techniques have been developed to eliminate these bone deformities including bone grafting, guided bone regeneration, distraction osteogenesis, use of growth factors and stem cells. Bone grafts consist of materials of natural or synthetic origin, implanted into the bone defect site, documented to possess bone healing properties. Currently, a variety of bone restorative materials with different characteristics are available, possesing different properties. Despite years of effort the 'perfect' bone reconstruction material has not yet been developed, a further effort is required to make this objective feasible. The aim of this article is to provide a contemporary and comprehensive overview of the grafting materials that can be applied in dentoalveolar reconstruction, discussing their properties, advantages and disadvantages, enlightening the present and the future perspectives in the field of bone regeneration.

Neovascularization in Ewing's sarcoma.

Ewing's sarcoma is the second most common bone malignancy in adolescents and young adults after osteosarcoma. Similar to other solid tumors, Ewing's sarcomas require an adequate vascular supply to grow and survive. The development and maintenance of vascular supply is accomplished via three main mechanisms; angiogenesis, vasculogenesis, and tumor cell vasculogenic mimicry. In addition, growth factors, parallel biochemical pathways and the tumor microenvironment are implicated in the initiation and maintenance of neovascularization. This article summarizes the different mechanisms and factors that contribute to neovascularization in Ewing's sarcoma, and discusses the significance of this phenomenon for current treatment options.

Thyroid hormone receptor alpha (TRa) tissue expression in ductal invasive breast cancer: A study combining quantitative immunohistochemistry with digital slide image analysis.

BACKGROUND: In breast cancer, hormonal receptors hold promise for developing novel targeted therapies. The thyroid exerts its actions via the thyroid hormone receptors alpha and beta. The clinical significance of the expression of thyroid hormone receptors in breast cancer is unclear. MATERIAL AND METHODS: We studied thyroid hormone receptor alpha (TRa) expression in 82 samples from 41 women with ductal invasive breast cancer and no thyroid disease. We performed quantitative immunohistochemistry with digital image analysis and correlated TRa expression with clinicopathological parameters. RESULTS: TRa was expressed in both normal breast epithelium and breast cancer, but expression in breast cancer was significantly lower. TRa was expressed significantly less in larger and grade III tumors. Conversely, breast cancers with lymphovascular invasion showed increased TRa expression compared to cancers without lymphovascular invasion. TRa expression was not significantly different between node-positive and node-negative breast cancers, or among different hormonal profiles and intrinsic subtypes. DISCUSSION: This is the first-in-human study to combine quantitative immunohistochemistry with image analysis to study TRa expression in women with ductal invasive breast cancer and no clinical or biochemical evidence of thyroid dysfunction. We confirm that TRa is expressed in both normal and malignant breast epithelium and suggest that TRa expression is downregulated during breast carcinogenesis. Larger and higher grade breast cancers demonstrate partial loss in TRa expression. Alterations in TRa expression take place even in the absence of clinical or biochemical thyroid disease. The underlying mechanism of these findings and their potential significance in survival and relapse mandate further research.

Targeting survivin as a potential new treatment for chondrosarcoma of bone.

Chondrosarcomas are malignant cartilage-forming bone tumors, which are intrinsically resistant to chemo- and radiotherapy, leaving surgical removal as the only curative treatment option. Therefore, our aim was to identify genes involved in chondrosarcoma cell survival that could serve as a target for therapy. siRNA screening for 51 apoptosis-related genes in JJ012 chondrosarcoma cells identified BIRC5, encoding survivin, as essential for chondrosarcoma survival. Using immunohistochemistry, nuclear as well as cytoplasmic survivin expression was analyzed in 207 chondrosarcomas of different subtypes. Nuclear survivin has been implicated in cell-cycle regulation while cytoplasmic localization is important for its anti-apoptotic function. RT-PCR was performed to determine expression of the most common survivin isoforms. Sensitivity to YM155, a survivin inhibitor currently in phase I/II clinical trial for other tumors, was examined in 10 chondrosarcoma cell lines using viability assay, apoptosis assay and cell-cycle analysis. Survivin expression was found in all chondrosarcoma patient samples. Higher expression of nuclear and cytoplasmic survivin was observed with increasing histological grade in central chondrosarcomas. Inhibition of survivin using YM155 showed that especially TP53 mutant cell lines were sensitive, but no caspase 3/7 or PARP cleavage was observed. Rather, YM155 treatment resulted in a block in S phase in two out of three chondrosarcoma cell lines, indicating that survivin is more involved in cell-cycle regulation than in apoptosis. Thus, survivin is important for chondrosarcoma survival and chondrosarcoma patients might benefit from survivin inhibition using YM155, for which TP53 mutational status can serve as a predictive biomarker.

Estimation of maspin's subcellular localization in invasive ductal breast cancer via light microscopy and computerized image analysis: a comparative study.

PURPOSE: Contradictory results have been reported concerning the role of maspin and its cellular distribution in breast cancer. The purpose of this study was to examine the subcellular localization (nuclear-cytoplasmic) of maspin in breast cancer and to compare the evaluation of maspin immunostaining via light microscopy (LM) to the estimation via computerized image analysis (CIA) system. We also examined correlations between maspin expression and several clinicopathological parameters. METHODS: The sample consisted of 48 primary invasive ductal carcinomas (IDC) of the breast. Maspin immunostaining was quantified and graded via LM by two pathologists, separately in the nuclear and cytoplasmic compartments. Total maspin expression was also estimated via CIA system. Univariate non-parametric statistics and stepwise multivariate ordinal logistic regression were performed. RESULTS: Both maspin components (nuclear and cytoplasmic) were closely associated with each other (p<0.001). Total maspin score was positively and closely associated with nuclear maspin (p<0.001) and cytoplasmic maspin (p<0.001). Total maspin , nuclear maspin and cytoplasmic maspin did not correlate significantly with either age, grade, T, N and M status, stage, micro vessel density (MVD) (CD34), ki-67, p53, estrogen receptor (ER) and HER-2 status, or with any of the 4 groups of the molecular classification. The only factor that showed a borderline inverse correlation with nuclear maspin (p=0.059) was progesterone receptors (PR) positivity. CONCLUSION: The cytoplasmic and nuclear fractions of maspin seem to be closely interwoven. Evidently, both mutually intertwined counterparts were independently reflected upon the total maspin levels measured by CIA. Future studies should ideally encompass all three approaches (nuclear, cytoplasmic, total) adopted herein.

Expression of tissue IGF 1, TGFbeta and EGFR in the sequential steps of intestinal adaptation in a rat model of short bowel syndrome.

BACKGROUND: The long-term morphological changes and the expression of tissue growth factors IGF 1, TGFbeta and EGFR in the gut mucosa, during the process of intestinal adaptation were examined. METHODS: Four groups of rats were used: a. Sham rats (n = 10) underwent bowel transection and reanastomosis, b. SBS rats underwent an 80% small bowel resection: group A rats (n = 10) were sacrificed 15 days after surgery, group B (n = 10), 30 days after surgery, and group C (n = 10), 60 days after surgery. Morphological small bowel parameters (villus height, lumen diameter and others) of adaptation were examined sequentially. Tissue samples were studied immunohistochemically for the detection of IGF 1, TGFbeta, and EGFR. RESULTS: There was a significant increase in all morphological parameters at day 15, in the intestinal samples; a further increase followed at day 30 and day 60 (p < 0.0001). Accordingly, an increase in the expression of IGF 1, TGFbeta and EGFR was noted at day 15 (p < 0.05), and at day 30 (NS). CONCLUSION: Intestinal adaptation is an ongoing process lasting more than 2 months after massive small bowel resection. Peptide growth factors are expressed in the intestine continuously during this period, but the first two weeks are the most critical for the mucosal growth.

Corticotropin-releasing hormone exerts direct effects on neuronal progenitor cells: implications for neuroprotection.

Neurogenesis during embryonic and adult life is tightly regulated by a network of transcriptional, growth and hormonal factors. Emerging evidence indicates that activation of the stress response, via the associated glucocorticoid increase, reduces neurogenesis and contributes to the development of adult diseases.As corticotrophin-releasing hormone (CRH) or factor is the major mediator of adaptive response to stressors, we sought to investigate its involvement in this process. Accordingly, we found that CRH could reverse the damaging effects of glucocorticoid on neural stem/progenitor cells (NS/PCs), while its genetic deficiency results in compromised proliferation and enhanced apoptosis during neurogenesis. Analyses in fetal and adult mouse brain revealed significant expression of CRH receptors in proliferating neuronal progenitors. Furthermore, by using primary cultures of NS/PCs, we characterized the molecular mechanisms and identified CRH receptor-1 as the receptor mediating the neuroprotective effects of CRH. Finally, we demonstrate the expression of CRH receptors in human fetal brain from early gestational age, in areas of active neuronal proliferation. These observations raise the intriguing possibility for CRH-mediated pharmacological applications in diseases characterized by altered neuronal homeostasis, including depression, dementia, neurodegenerative diseases, brain traumas and obesity.

Does VEGF have an effect on the survival of a long random skin flap by its application at the recipient area?

BACKGROUND: Vascular endothelial growth factor (VEGF) is a hormone-like molecule which has been shown to act on a specific receptor system and in this way to be the basic regulator of angiogenesis. The effect on the survival of a long random skin flap was examined by exogenous administration of this cytokine, at flap's recipient site. MATERIALS & METHODS: A standard dorsal skin flap measuring 1.5 x 7.5cm was elevated in eighteen wistar rats with the pedicle centered and attached between the lower angles of the scapulae. The length to width ratio was relatively high (5:1). The rats were divided in two groups of nine. In group A, flap was elevated and a skin defect was created next to it. Normal saline was injected into the fascia of the defect and the flap was transposed and secured over the previously created recipient site. In group B, flap was elevated and transposed to a previous created defect, as before, where, this time, injections of VEGF were applied into the fascia of the recipient bed. Seven days later the rats were euthanized and the flaps were excised. The underlying fascias of the recipient beds were also excised in the same dimensions. The specimens were measured, photographed and put into formalin 10%. Immunohistochemical staining and histological analysis followed. RESULTS: The differentiation between the surviving and the necrotic skin was macroscopically clear within seven days time. In group A, the mean flap survival percentage was 36.8%. In group B the percentage was 56.3%, respectively. Neovascularization of the fascia of the recipient bed was also demonstrated when VEGF had been injected. CONCLUSIONS: Exogenous administration of VEGF into the recipient bed of a skin flap improved the survival rate even though the flap's length was relatively high compared to its width.

The significance of DNA image cytometry and Edmondson-Steiner grading on prognosis after curative resection of hepatocellular carcinoma.

PURPOSE: Hepatocellular carcinoma (HCC) is the commonest primary cancer of the liver. Hepatic resection remains the main curative option, although the incidence of disease recurrence in the remaining hepatic parenchyma is high and accounts for the leading cause of death post resection. For this reason, the need to identify prognostic factors which may determine treatment response and survival is of paramount importance. In this study we assessed whether DNA image cytometry and Edmondson-Steiner grading could be used as prognostic factors in a cohort of patients with HCC undergoing radical hepatic resection. METHODS: Forty-four patients with HCC who underwent radical resection were retrospectively analyzed. Histological grading according to Edmondson and Steiner and DNA ploidy using DNA image cytometry, were the two parameters analyzed. Pearson's x(2) or Fisher's exact tests were used to test for any associations between categorical variables. Univariate semi-parametric Cox proportional hazard regression models were used to assess the effect of explanatory variables on death. All reported p values were based on two-sided tests and compared to a significance level of 0.05. RESULTS: In univariate Cox regression analysis, adverse survival outcome was strongly associated with high DNA score and advanced histological grading. Patients with ploidy score >2.2 had 3.95 times higher probability of death, as compared to those with ploidy score ≤ 2.2. Edmondson-Steiner grades III and IV were also associated with 20.49 and 34.47 higher probability of death respectively as compared to grade I. CONCLUSION: Our results validate the prognostic significance of DNA image cytometry and Edmondson-Steiner grading following curative resection of HCC.

Experimental study of tendon healing early phase: is IGF-1 expression influenced by platelet rich plasma gel?

BACKGROUND: It is well established that growth factors play a critical role in the healing process of connective tissues. To our knowledge, there are no studies in literature concerning the influence of PRP on growth factors expression. HYPOTHESIS: The aim of this study was to assess the effect of a single application of platelet rich plasma (PRP) gel in a patellar tendon defect on the spatial and temporal expression of Insulin-like Growth Factor 1 (IGF-1) during tendon healing. MATERIALS AND METHODS: Twenty-four animals were randomized to receive PRP (PRPFast, Bioteck) in a gel form (PRP group) and 24 to serve as untreated controls (Control group). A defect of 3 mm x 10 mm was surgically created on the tendon under general anaesthetic and in the PRP group, PRP gel was applied to fill the tendon defect whereas no treatment was applied in the control group. Six animals (12 limbs) from each treatment-group were sacrificed after one, two, three and four weeks following treatment. Histological and immunohistochemical staining were performed. RESULTS: Histology revealed a faster healing process in the tendons of PRP group in comparison with the controls. In the first 2 weeks of healing, IGF-1 was found intracellularly in various type cells, whereas in the last 2 weeks of healing, IGF-1 was detected mainly in tenocytes. Both cytoplasmic and nuclear expressions were present, whereas the larger amounts of immunoexpression were localized in both epitenon and endotenon. A superior expression of IGF-1 was seen in PRP group compared with controls (p<0.0001) in both the epitenon and endotenon at each time point except at 4th week of healing where a superior expression of IGF-1 was shown in the endotenon of control group, compared to the PRP group (p<0.0001). CONCLUSION: PRP may improve tendon defect healing by overexpression of IGF-1. LEVEL OF EVIDENCE: Laboratory control animal study.

Adrenaline attenuates the acute lung injury after intratracheal lipopolysaccharide instillation: an experimental study.

Endotoxin is a major cause of endotoxinemia, sepsis, and pneumonia due to gram-negative bacteria. Experimental endotoxin administration via the tracheal route has been extensively used to study the biological and pathophysiologic pathways of inflammation. In particular, experimental endotoxin instillation in the respiratory tree has allowed an extended research with regard to the local response of the lungs to the pathogenic stimulus. This study aims (a) to define early events in the inflammatory cascade and (b) to evaluate the efficacy of adrenaline to ameliorate the acute pulmonary inflammation in vivo after administration of intratracheal lipopolysaccharide (LPS) in an in vivo animal model. Two groups of animals were used for that purpose, a control group (single LPS administration) and a study group (subcutaneous adrenaline infusion following LPS administration). We found that mononuclear recruitment, along with an increased population of CD4+ T lymphocytes, is an early event during the course of LPS-challenged inflammation. In the study group, we determined that adrenaline mediated the lung inflammation in a statistically significant degree. By the use of immunohistochemistry, we identified (1) an increased population of CD4+ T lymphocytes in the inflammatory infiltrate, further endorsing the hypothesis that T-helper lymphocytes, along with macrophages, secrete cytokines which amplify the inflammatory response, and (2) an upregulation of ICAM-1 expression, suggesting an important role in the early pathogenesis of LPS-induced acute lung injury. Our study establishes that systemic adrenaline administration after LPS instillation may ameliorate the inflammatory lung response in vivo.

Association of hypospadias and cardiac defect in a Parvovirus B19-infected stillborn: a causality relation?

Parvovirus B19 intrauterine infection is a known cause of hydrops fetalis and fetal death. It is also associated with congenital malformations, although the teratogenic potential seems to be low. Postmortem examination of a male stillborn of 29 gestational weeks revealed mild subcutaneous edema, malformed micropenis, perineoscrotal hypospadias and atrial septal defect, along with fetal erythroblastosis and villitis. Polymerase chain reaction detected Parvovirus B19 DNA genome in tissues from the fetus and the placenta, confirming the hypothesis of an intrauterine infection.

Caspase-3 immunohistochemical expression is a marker of apoptosis, increased grade and early recurrence in intracranial meningiomas.

Caspase-3 is the ultimate executioner caspase that is essential for the nuclear changes associated with apoptosis. We investigated caspase-3 immunohistochemical expression in 58 primary intracranial meningiomas, using one monoclonal antibody detecting both precursor and cleaved caspase-3 (CPP32) and a second recognizing only the cleaved activated form (ASP175). Caspase-3 expression was analyzed in relation to baseline apoptosis-as illustrated by the expression of anti-single stranded DNA (ss-DNA), the antiapoptotic protein bcl-2, proliferation indices (Ki-67, PCNA, topoisomerase IIa, mitosin C), hormonal status (estrogen, progesterone, androgen receptors), standard clinicopathological parameters and patients' disease-free survival. Caspase-3 immunostaining was observed in 62% of cases for CPP32 and in 24% for ASP175. In both instances, the labeling index (LI) was significantly correlated with ss-DNA LI (p=0.038 and p=0.018). CPP32 but not ASP175 LI positively correlated with the mitotic index (p=0.001) and PCNA LI (p=0.004). Both CPP32 and ASP175 LIs were increased in nonbenign meningiomas (p<0.0001 and p=0.0035 respectively). In univariate and multivariate survival analyses, caspase-3 predicted meningioma recurrence, independently affecting disease-free survival (p=0.011 and p=0.047 respectively for CPP32; p<0.0001 and p=0.012 respectively for ASP175). Caspase-3 may prove to be a useful predictor of early recurrence in a group of neoplasms characterized by the frequent discordance between histology and clinical behavior.

Effect of green tea on angiogenesis and severity of atherosclerosis in cholesterol-fed rabbit.

BACKGROUND AND AIMS: Since the development of the atherosclerotic plaque requires the growth of new microvessels in the plaque itself (vasa vasorum), we postulated that green tea may exert an anti-atherogenic effect. METHODS AND RESULTS: Thirteen male New Zealand white rabbits were studied for 17 weeks. All rabbits were fed an hypecholesterolemic diet. After 2 weeks of adaptation rabbits were randomly assigned into two groups. Animals in Group A were fed the hypercholesterolemic diet and received plain tap water ad libitum. Animals in Group B were fed with the same diet and furthermore received 2.5% (g/g) green tea for 17 weeks. CONCLUSION: According to our results the atherosclerotic lesions were more severe in Group B than in Group A specimens. Also, the number of VEGF positively stained foam cells and smooth muscle cells of Group B were significantly greater than in Group A. About 30% less plaque was found in Group A than in the control group (Group B). So, our study showed that the consumption of green tea leads to a reduction of atherosclerosis as well as a significant decrease of VEGF expression in the atherosclerotic plaque of rabbit aorta. The hypothesis that probably green tea may produce its anti-atherogenetic effect through an anti-angiogenetic mechanism needs more investigation.