Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.

Objective To determine the value of patient-reported symptoms in diagnosing endometriosis.Design A national case-control study.Setting Data from the UK General Practice Research Database for years 1992-2001.Sample A total of 5540 women aged 15-55 years, diagnosed with endometriosis, each matched to four controls without endometriosis.Methods Data were analysed to determine whether specific symptoms were highly indicative of endometriosis. Odds ratios for these symptoms were derived by conditional logistic regression analysis. . Women with endometriosis were also found to consult the doctor more frequently than the controls and were twice as likely to have time off work.Conclusions Specific symptoms and frequent medical consultation are associated with endometriosis and appear useful in the diagnosis. Endometriosis may coexist with or be misdiagnosed as pelvic inflammatory disease or IBS.