Insights into molar-incisor hypomineralisation in past populations: A call to anthropologists.

OBJECTIVE: Molar incisor hypomineralisation (MIH) is a developmental defect of enamel affecting the first permanent molars and often the incisors and affecting approximately 13% of the current population worldwide. Here, we aim to highlight potential differential diagnoses of MIH in archaeological collections (taphonomic discoloration, amelogenesis imperfecta, fluorosis, rachitic teeth, etc.). METHODS: Causative factors of dental discolourations are identified through a literature review. RESULTS: In an archaeological context, the sediments contained in the burial soil can lead to tooth discoloration. Taphonomic staining of the dentition may have a similar appearance to enamel hypomineralisation, and thus is a confounding factor that has the potential to cause miscalculation of the true prevalence of MIH within archaeological collections. Some rare medieval cases are reported in the modern literature but without microanalysis, misdiagnosis is possible. The aetiological factors of MIH are unknown but probably follow the multifactorial model involving systemic medical and genetic factors. CONCLUSIONS: Systematic detection and diagnosis of MIH during anthropological studies is therefore of great interest. SIGNIFICANCE: The hypotheses that only contemporary agents are causative factors of MIH could be refuted by the discovery of individuals living before medication or pollutants. The identification of MIH in a group of individuals also provides information regarding the health status of a population and reflects stress occurring during the period of mineralisation of the first permanent molars after secretion of the enamel matrix. LIMITATIONS: Taphonomic alterations of archaeological remains prevent MIH diagnosis. SUGGESTIONS FOR FUTURE RESEARCH: MIH diagnosis can be difficult in archaeological series and further non-destructive methods (microtomography, elemental analyses, etc.) are required.

The genomic history of the Iberian Peninsula over the past 8000 years.

We assembled genome-wide data from 271 ancient Iberians, of whom 176 are from the largely unsampled period after 2000 BCE, thereby providing a high-resolution time transect of the Iberian Peninsula. We document high genetic substructure between northwestern and southeastern hunter-gatherers before the spread of farming. We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia's ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European-speaking regions but also into non-Indo-European-speaking ones, and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia. Additionally, we document how, beginning at least in the Roman period, the ancestry of the peninsula was transformed by gene flow from North Africa and the eastern Mediterranean.

First fossil evidence of an "interglacial refugium" in the Pyrenean region.

A refugium is generally understood as an area where temperate species survive cold periods, such as the Iberian, Italian, or Balkan Peninsulas in Europe. Strictly speaking, this definition refers to what is known as a glacial refugium. However, there are various types of lesser-known refugia such as the interglacial refugium, which denotes a mountainous region at low latitudes, such as the Pyrenees, where species adapted to the cold survive during interstadial periods. The small-vertebrate association from the sequence of Cova Colomera, which is located on the southern face of the Pyrenees and contains the final cold spell of the Late Pleistocene and the beginnings of the temperate period in which we currently find ourselves (the Holocene), could constitute the first fossil evidence of such an interglacial refugium, thus providing new paleoecological data on the phenomenon.

Substituiçäo valvar com próteses mecânicas de duplo folheto / Valve replacement with mechanical bileaflet prostheses

OBJETIVO: O objetivo deste estudo é analisar a experiência do Instituto do Coraçäo com a utilizaçäo de próteses mecânicas de duplo folheto. CASUISTICA E METODOS: No período compreendido entre junho de 1989 e agosto de 1998, foram implantadas 323 próteses mecânicas de duplo folheto em 300 pacientes. A idade média foi de 38,7 + ou - 18,4 anos. Cento e noventa e um (63,7 por cento) pacientes eram do sexo masculino. A etiologia foi reumßtica em 161 (53,7 por cento) pacientes. Foram realizadas 186 substituiçöes da valva aórtica, 89 da valva mitral, 2 da valva tricúspide, 22 substituiçöes mitro-aórticas e 1 mitro-tricuspídea. Quanto à classe funcional (CF), 73 (24,3 por cento) pacientes se encontravam em CF IV, 165 (55,4 por cento) em CF III e 61 (20,3 por cento) em CF II. RESULTADOS: A mortalidade hospitalar foi de 9 por cento (27 pacientes), sendo de 13,5 por cento no grupo mitral, 7,5 por cento no grupo aórtico e 4,5 por cento no mitro-aórtico. As taxas linearizadas dos eventos no pós-operatório tardio säo: 0,2 por cento pacientes/ano (pac./ano) para endocardite, 0,3 por cento pac./ano para escape paravalvar, 0,2 por cento pac./ano para hemorragia relacionada à anticoagulaçäo e 1,0 por cento pac./ano para tromboembolismo. No pós-operatório tardio 213 (91 por cento) pacientes encontram-se em classe funcional I ,16 (6,8 por cento) em CF II e 4 (1,7 por cento) em CF III e 1 (0,5 por cento) em CF IV. A sobrevida actuarial em 9 anos foi de 68,1 + ou - 15,5 por cento para a posiçäo mitral e 67,5 + ou - 10,8 por cento para a aórtica. CONCLUSAO: Concluímos que os resultados com a utilizaçäo das próteses mecânicas de duplo folheto säo satisfatórios