Stem cell regulatory gene expression in human adult dental pulp and periodontal ligament cells undergoing odontogenic/osteogenic differentiation

Introduction During development and regeneration, odontogenesis and osteogenesis are initiated by a cascade of signals driven by several master regulatory genes. Methods In this study, we investigated the differential expression of 84 stem cell–related genes in dental pulp cells (DPCs) and periodontal ligament cells (PDLCs) undergoing odontogenic/osteogenic differentiation. Results Our results showed that, although there was considerable overlap, certain genes had more differential expression in PDLCs than in DPCs. CCND2, DLL1, and MME were the major upregulated genes in both PDLCs and DPCs, whereas KRT15 was the only gene significantly downregulated in PDLCs and DPCs in both odontogenic and osteogenic differentiation. Interestingly, a large number of regulatory genes in odontogenic and osteogenic differentiation interact or crosstalk via Notch, Wnt, transforming growth factor β (TGF-β)/bone morphogenic protein (BMP), and cadherin signaling pathways, such as the regulation of APC, DLL1, CCND2, BMP2, and CDH1. Using a rat dental pulp and periodontal defect model, the expression and distribution of both BMP2 and CDH1 have been verified for their spatial localization in dental pulp and periodontal tissue regeneration. Conclusions This study has generated an overview of stem cell–related gene expression in DPCs and PDLCs during odontogenic/osteogenic differentiation and revealed that these genes may interact through the Notch, Wnt, TGF-β/BMP, and cadherin signalling pathways to play a crucial role in determining the fate of dental derived cell and dental tissue regeneration. These findings provided a new insight into the molecular mechanisms of the dental tissue mineralization and regeneration

Microbial risk from rainwater tanks in South East Queensland

Quantitative Microbial Risk Assessment (QMRA) analysis was used to quantify the risk of infection associated with the exposure to pathogens from potable and non-potable uses of roof-harvested rainwater in South East Queensland (SEQ). A total of 84 rainwater samples were analysed for the presence of faecal indicators (using culture based methods) and zoonotic bacterial and protozoan pathogens using binary and quantitative PCR (qPCR). The concentrations of Salmonella invA, and Giardia lamblia β-giradin genes ranged from 65-380 genomic units/1000 mL and 9-57 genomic units/1000 mL of water, respectively. After converting gene copies to cell/cyst number, the risk of infection from G. lamblia and Salmonella spp. associated with the use of rainwater for bi-weekly garden hosing was calculated to be below the threshold value of 1 extra infection per 10,000 persons per year. However, the estimated risk of infection from drinking the rainwater daily was 44-250 (for G. lamblia) and 85-520 (for Salmonella spp.) infections per 10,000 persons per year. Since this health risk seems higher than that expected from the reported incidences of gastroenteritis, the assumptions used to estimate these infection risks are critically discussed. Nevertheless, it would seem prudent to disinfect rainwater for potable use.

Differentially Expressed Protein Profile of Human Dental Pulp Cells in the Early Process of Odontoblast-like Differentiation In Vitro

Dental pulp cells (DPCs) are capable of differentiating into odontoblasts that secrete reparative dentin after pulp injury. The molecular mechanisms governing reparative dentinogenesis are yet to be fully understood. Here we investigated the differential protein profile of human DPCs undergoing odontogenic induction for 7 days. Using two-dimensional differential gel electrophoresis coupled with matrix-assisted laser adsorption ionization time of flight mass spectrometry, 2 3 protein spots related to the early odontogenic differentiation were identified. These proteins included cytoskeleton proteins, nuclear proteins, cell membrane-bound molecules, proteins involved in matrix synthesis, and metabolic enzymes. The expression of four identified proteins, which were heteronuclear ribonuclear proteins C, annexin VI, collagen type VI, and matrilin-2, was confirmed by Western blot and real-time realtime polymerase chain reaction analyses. This study generated a proteome reference map during odontoblast- like differentiation of human DPCs, which will be valuable to better understand the underlying molecular mechanisms in odontoblast-like differentiation.

The varied presentation of metastatic melanoma in fine needle aspiration cytology of the breast

Objective To identify cytomorphological patterns of metastatic melanoma (MM) in breast fine needle aspiration (FNA) specimens and highlight the differential diagnoses and features most useful in identifying MM. Methods The clinical, radiological and FNA findings of 16 cases were reviewed. Cytological features evaluated related to cell arrangement, size and shape of cells, nuclear and cytoplasmic features, and the presence or absence of necrosis. Results The series consisted of 14 females and two males, ranging in age from 24 to 83 years (mean = 50 years). A previous history of melanoma was available in 12/16 (75%) cases at the time of FNA reporting; however the clinical/radiological impression in 4/16 cases was of a breast cyst. The cases were classified into six morphological variants: classical (8/16), pseudopapillary (3/16), spindle-cell (1/16), melanin-rich (1/16), pleomorphic (2/16) and lymphoma-like (1/16). The varying patterns raised a wide range of differential diagnoses; however, discohesion, binucleation and granular cytoplasm were the major features seen in 94% of all cases. In 14/16 cases (88%), plasmacytoid cells, prominent nucleoli and cytoplasmic vacuolation were identified. Melanin and multinucleation were detected in 44% of cases and intranuclear cytoplasmic invaginations in 63%. Necrosis was present in more than half of the cases (56%). Conclusion MM should be considered in the differential diagnosis of breast FNA specimens when atypical cells are seen that present as plasmacytoid cells in a dispersed or pseudopapillary pattern, or as spindle, pleomorphic or pigmented cells. These features, combined with clinical history and immunocytochemistry, may assist in correctly identifying MM and directing optimal treatment.