Cementochronology, to cut or not to cut?

One of the continuing problems in paleopathology and paleoepidemiology is an inability to accurately age adult skeletons. Accurate age estimations are critical to the proper evaluation of population health and are necessary in circumventing certain aspects of the osteological paradox. Cementochronology is most likely the only age indicator in anthropology that directly considers a continuously growing tissue and does not require either complex statistical manipulations or the use of a reference population. The major issues and recent advances linked to this technique are reviewed for its successful implementation. This review is a partial outcome of an international research program initiated in 2010 to develop and expand cementochronology. Because cementochronology is a reasonably straightforward histological protocol, it can be implemented in less than 24h for one tooth at a relatively low cost. The only aspect of cementochronology that requires extensive previous experience is the counting of increments. These unique aspects largely justify the regular implementation of cementochronology in paleoepidemiology and paleopathology in the confident exploration of "population health" issues and demographic inferences.

The impact of periodontal disease on cementochronology age estimation.

Estimating an individual's age at death is essential for post-mortem identification, paleopathology and paleodemography. With substantial development over the past 10 years in cementochronology analyses, some concerns have arisen that oral pathological conditions may artificially reduce or increase cementum apposition. The objective of this study was to observed the impact of periodontal disease on acellular cementum and on the reliability of cementochronology to test its accuracy for estimating individual age at death. The study included 41 teeth presenting different degrees of bone destruction, extracted from 18 individuals affected by untreated periodontal disease. The results demonstrated that the degree of alveolysis had only limited effects on the counting of cementum annulations in the middle (rp=0.92, p<0.01 between estimated and civil age) and the cervical (rp=0.85, p<0.01) thirds of the root, whereas in the apical third, the increments were affected considerably. This cementum reactive process compensates for bone destruction and loss of the attachment apparatus. These data suggest that cementum could continue to grow at a slower rate despite bone destruction due to periodontal disease. Cementochronology can thus be applied to teeth with a damaged periodontium by sectioning the middle third of the root.

The leprosarium of Saint-Thomas d'Aizier: The cementochronological proof of the medieval decline of Hansen disease in Europe?

This study compares the adult survivorship profiles of people interred in the Saint-Thomas d'Aizier leprosarium, estimated by cementochronology, to eight archaeological series in northern France dated from Late Antiquity to the Late Middle Ages, periods of significant visibility for Hansen's disease (leprosy). The goals are to understand the impact of leprosy on various social groups and to explore the cause of leprosy's decline by analyzing male and female fertility. Survival rates differed between medieval leprosy-free sites and the Saint-Thomas d'Aizier leprosarium, although this difference was statistically significant only for the female leprosarium sample. The selective female frailty, a consequence of social exclusion and the collapse of the quality of life, combined with the infertility of lepromatous couples, offer a multi-causal explanation to the end of the expansion and then decline of leprosy in southern and western European countries.

Cementochronology and sex: A reappraisal of sex-associated differences in survival in past French societies.

The objective of the present study is to test our general knowledge of sex-specific survival differences in past northern France societies by implementing the tooth cementum annulations method of age estimation (i.e., cementochronology) to bio-archaeological series. 1255 individual estimated ages at death covering a millennium from the 3rd c. AD to the 15th c. AD matched different patterns of sex mortality from the late Antiquity to the Late Middle Age. Female survival curves are consistently inferior to those of their male counterparts. Maternal mortality is clearly visible in survival curves between 20 and 50 years of age in individual sites and pooled samples. Variations of sex mortalities also affected sites with peculiar recruitment, such as religious communities, pathological samples, leprosaria, and migrants. Whisker plots of median ages at death variations confirmed in both sex that populations within the Early Middle Ages were better off compared to Late Antiquity and Late Medieval Ages when group inequalities prevailed. Due to its sensitivity and applicability to small samples, cementochronology should be extended to other series.

Addressing Therapeutic Options for Ebola Virus Infection in Current and Future Outbreaks.

Ebola virus can cause severe hemorrhagic disease with high fatality rates. Currently, no specific therapeutic agent or vaccine has been approved for treatment and prevention of Ebola virus infection of humans. Although the number of Ebola cases has fallen in the last few weeks, multiple outbreaks of Ebola virus infection and the likelihood of future exposure highlight the need for development and rapid evaluation of pre- and postexposure treatments. Here, we briefly review the existing and future options for anti-Ebola therapy, based on the data coming from rare clinical reports, studies on animals, and results from in vitro models. We also project the mechanistic hypotheses of several potential drugs against Ebola virus, including small-molecule-based drugs, which are under development and being tested in animal models or in vitro using various cell types. Our paper discusses strategies toward identifying and testing anti-Ebola virus properties of known and medically approved drugs, especially those that can limit the pathological inflammatory response in Ebola patients and thereby provide protection from mortality. We underline the importance of developing combinational therapy for better treatment outcomes for Ebola patients.

Tuberculosis and survival in past populations: A paleo-epidemiological appraisal.

Historical assessments of the last two centuries consistently placed tuberculosis as the leading cause of mortality. However, for earlier periods, we can only calculate the frequencies of archaeological bone lesions, which tell us little about the real impact of the disease on mortality. These lesions are usually observed in individuals who have developed immune resistance, which is visible as healed osteo-articular lesions. This study aimed to test the differential impacts of tuberculosis, cribra orbitalia and cribra femoris on adult survival and sex-based survival. We analyzed 28 French adult samples from the Antiquity and the Early Middle Ages. The age-at-death of 1480 individuals was estimated using cementochronology. Survival curves and median age-at-death were calculated to test new hypotheses that challenge the parasitic and deficiency theories of bone stress markers. Comparisons between carriers and non-carriers provided new information concerning the plausible causes of bone stress markers related to infections and TB. The most likely hypothesis is skeletal demineralization and osteoclastic resorption, which are usually observed close to tubercular granuloma or distant from active lesions. The bone marrow niche of Mycobacterium tuberculosis within CD271(+) BM-MSCs stem cells is the proposed explanation for the localized cortical resorption that is observed in bone stress markers.

Bilateral fractures of the scapula: Possible archeological examples of beatings from Europe, Africa and America.

Traumatic injuries to the scapula have received little attention in the paleopathological literature. They are rarely encountered in medical emergencies today due to the overlying muscles that protect the bone; they comprise just 1% of all fractures. This collaborative project brings together five cases of bilateral fractures of the scapulae in four ancient populations from three different time periods and three continents (France, Sudan and USA). It is thus an opportunity to interpret bilateral scapula fracture etiology by suggesting a cause that could have been present in all contexts, namely direct trauma such as might take place during beating with heavy sticks or other blunt force weapons. We also argue that oval defects with rounded margins in scapular bodies are less likely to be congenital anatomical variants than the result of healed trauma.