Utilization of dental health services by Danish adolescents attending private or public dental health care systems

The objectives of the study were: 1) to describe the choice of dental care system among 16-year-olds, 2) to describe the utilization of dental services among 16-17-year-olds enrolled in either public or private dental care systems, and to compare the dental services provided by the alternative systems. The study comprised 1,245 adolescents from 3 municipalities; the historical cohort study design was applied; and data were collected from dental records (public dental service) and dental claims (private practice). At age 16, 12% preferred being enrolled in the private practice system, while 88% remained in the public dental care system. During the 2-year study period the attendance rate was 99% for the public system, while 90% attended the private practice system (P < 0.001). Preventive dental services were provided more frequently by the public than the private system (P < 0.001). Despite the fact that the economic barrier was eliminated a lower attendance rate was observed for patients transferred to the private practice system.     

Pluripotent Stem Cells as a Potential Tool for Disease Modelling and Cell Therapy in Diabetes

Diabetes mellitus is the most prevailing disease with progressive incidence worldwide. To date, the pathogenesis of diabetes is far to be understood, and there is no permanent treatment available for diabetes. One of the promising approaches to understand and cure diabetes is to use pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced PCSs (iPSCs). ESCs and iPSCs have a great potential to differentiate into all cell types, and they have a high ability to differentiate into insulin-secreting β cells. Obtaining PSCs genetically identical to the patient presenting with diabetes has been a longstanding dream for the in vitro modeling of disease and ultimately cell therapy. For several years, somatic cell nuclear transfer (SCNT) was the method of choice to generate patient-specific ESC lines. However, this technology faces ethical and practical concerns. Interestingly, the recently established iPSC technology overcomes the major problems of other stem cell types including the lack of ethical concern and no risk of immune rejection. Several iPSC lines have been recently generated from patients with different types of diabetes, and most of these cell lines are able to differentiate into insulin-secreting β cells. In this review, we summarize recent advances in the differentiation of pancreatic β cells from PSCs, and describe the challenges for their clinical use in diabetes cell therapy. Furthermore, we discuss the potential use of patient-specific PSCs as an in vitro model, providing new insights into the pathophysiology of diabetes.     

A tunable silk–alginate hydrogel scaffold for stem cell culture and transplantation

One of the major challenges in regenerative medicine is the ability to recreate the stem cell niche, which is defined by its signaling molecules, the creation of cytokine gradients, and the modulation of matrix stiffness. A wide range of scaffolds has been developed in order to recapitulate the stem cell niche, among them hydrogels. This paper reports the development of a new silk–alginate based hydrogel with a focus on stem cell culture. This biocomposite allows to fine tune its elasticity during cell culture, addressing the importance of mechanotransduction during stem cell differentiation. The silk–alginate scaffold promotes adherence of mouse embryonic stem cells and cell survival upon transplantation. In addition, it has tunable stiffness as function of the silk–alginate ratio and the concentration of crosslinker – a characteristic that is very hard to accomplish in current hydrogels.     

Prognostic significance of Ki-67 in salivary gland carcinomas

J Oral Pathol Med (2012) 41 : 598–602 Background: Salivary gland carcinomas are a heterogeneous group of tumors with varying malignant potential. In this study, we evaluated the proliferative marker Ki‐67 in salivary gland carcinomas and related the Ki‐67 index to clinical data. Methods: A total of 176 salivary gland carcinomas of 13 different subtypes were stained immunohistochemically for Ki‐67. The number of Ki‐67 positive cells was counted and the Ki‐67 index was calculated as the percentage of positive tumor cells. Results: The Ki‐67 median value was 26 (range 1–99). The median follow‐up time was 6.9 years (range 0–19 years). The 5‐ and 10‐year crude survival was 70% and 59%, respectively. In univariate analysis, Ki‐67 index, stage, vascular invasion and tumor grade were significantly related to crude survival, but in multivariate analysis only Ki‐67 index, age, and stage were independent prognostic factors. Conclusion: We showed that irrespective of subtyping, grading or morphological appearance of tumor, the Ki‐67 index is an important and independent prognosticator. Clinical and histo‐pathological data must be considered, when planning the treatment of the individual patient. We have shown that besides stage and age of the patient, Ki‐67 is a strong, independent prognostic factor.     

Caspase-8 mediates caspase-1 processing and innate immune defense in response to bacterial blockade of NF-κB and MAPK signaling

Toll-like receptor signaling and subsequent activation of NF-κB– and MAPK-dependent genes during infection play an important role in antimicrobial host defense. The YopJ protein of pathogenic Yersinia species inhibits NF-κB and MAPK signaling, resulting in blockade of NF-κB–dependent cytokine production and target cell death. Nevertheless, Yersinia infection induces inflammatory responses in vivo. Moreover, increasing the extent of YopJ-dependent cytotoxicity induced by Yersinia pestis and Yersinia pseudotuberculosis paradoxically leads to decreased virulence in vivo, suggesting that cell death promotes anti-Yersinia host defense. However, the specific pathways responsible for YopJ-induced cell death and how this cell death mediates immune defense against Yersinia remain poorly defined. YopJ activity induces processing of multiple caspases, including caspase-1, independently of inflammasome components or the adaptor protein ASC. Unexpectedly, caspase-1 activation in response to the activity of YopJ required caspase-8, receptor-interacting serine/threonine kinase 1 (RIPK1), and Fas-associated death domain (FADD), but not RIPK3. Furthermore, whereas RIPK3 deficiency did not affect YopJ-induced cell death or caspase-1 activation, deficiency of both RIPK3 and caspase-8 or FADD completely abrogated Yersinia-induced cell death and caspase-1 activation. Mice lacking RIPK3 and caspase-8 in their hematopoietic compartment showed extreme susceptibility to Yersinia and were deficient in monocyte and neutrophil-derived production of proinflammatory cytokines. Our data demonstrate for the first time to our knowledge that RIPK1, FADD, and caspase-8 are required for YopJ-induced cell death and caspase-1 activation and suggest that caspase-8–mediated cell death overrides blockade of immune signaling by YopJ to promote anti-Yersinia immune defense.The innate immune response forms the first line of defense against pathogens. Microbial infection triggers the activation of pattern recognition receptors, such as Toll-like receptors (TLRs) on the cell surface or cytosolic nucleotide binding domain leucine-rich repeat family proteins (NLRs) (1). TLRs induce NF-κB and MAPK signaling to direct immune gene expression, whereas certain NLRs direct the assembly of multiprotein complexes known as inflammasomes that provide platforms for caspase-1 or -11 activation (2). Active caspase-1 and -11 mediate cleavage and secretion of the IL-1 family of proteins and a proinflammatory cell death termed pyroptosis. However, microbial pathogens can interfere with various aspects of innate immune signaling, and the mechanisms that mediate effective immune responses against such pathogens remain poorly understood. Pathogenic Yersiniae cause diseases from gastroenteritis to plague and inject a virulence factor known as YopJ, which inhibits NF-κB and MAPK signaling pathways in target cells (2–4). YopJ activity inhibits proinflammatory cytokine production (4) and induces target cell death (5). YopJ activity induces processing of multiple caspases, including caspases-8, -3, -7, and -1 (6–8). Nevertheless, Yersinia-infected cells exhibit properties of both apoptosis and necrosis (9, 10), and no specific cellular factors have been identified as being absolutely required for YopJ-induced caspase activation and cell death. We previously found that the inflammasome proteins NLR CARD 4 (NLRC4), NLR Pyrin 3 (NLRP3), and apoptosis-associated speck-like protein containing a CARD (ASC), are dispensable for YopJ-induced caspase-1 processing and cell death (11). Thus, additional pathways likely mediate YopJ-induced caspase-1 activation and cell death.Death receptors, such as TNF receptor and Fas, mediate caspase-8–dependent apoptosis via a death-inducing signaling complex containing receptor-interacting serine/threonine kinase 1 (RIPK1), caspase-8, and Fas-associated death domain (FADD) (12, 13). Whether these proteins are required for Yersinia-induced cell death, and whether this death contributes to antibacterial immune responses, is not known. The Ripoptosome complex, which contains RIPK1, FADD, caspase-8, as well as RIPK3 and cFLIP, regulates apoptosis, programmed necrosis, and survival in response to various stimuli including signaling by the TLR adaptor TRIF (14, 15). Because YopJ-induced cell death is inhibited in the absence of either TLR4 or TRIF (17) we sought to determine whether YopJ-dependent cell death and caspase-1 activation is regulated by caspase-8 or RIPK3 and to define the role of YopJ-dependent cell death in host defense. Here, we describe a previously unappreciated requirement for RIPK1, FADD, and caspase-8, but not RIPK3, in YopJ-induced caspase-1 activation and cell death. Critically, loss of caspase-8 in the hematopoietic compartment resulted in a failure of innate immune cells to produce proinflammatory cytokines in response to Yersinia infection and severely compromised resistance against Yersinia infection. Our data suggest that caspase-8–mediated cell death in response to blockade of NF-κB/MAPKs by YopJ allows for activation of host defense against Yersinia infection. This cell death may thus enable the immune system to override inhibition of immune signaling by microbial pathogens.     

Parotid carcinoma: expression of kit protein and epidermal growth factor receptor

OBJECTIVES: Our aim is to investigate the expression of kit protein (KIT) and epidermal growth factor receptor (EGFR) in parotid carcinomas in order to correlate the expression to histology and prognosis. Further we want to perform mutation analysis of KIT-positive adenoid cystic carcinomas. PATIENTS AND METHODS: Formalin-fixed paraffin-embedded sections from 73 patients with parotid gland carcinomas were used for the study. The sections were stained with both KIT and EGFR polyclonal antibodies. Twelve KIT-positive adenoid cystic carcinomas were examined for c-kit mutation in codon 816. RESULTS: Of all carcinomas 25% were KIT-positive and 79% were EGFR-positive. Ninety-two percentage of the adenoid cystic carcinomas were KIT-positive. None of the adenoid cystic carcinomas had mutations in codon 816 of the c-kit gene. CONCLUSION: Neither KIT- nor EGFR-expression seem to harbour significant prognostic information. Adenoid cystic carcinomas express KIT, but no mutations in codon 816 of the c-kit gene were identified.