Animal Board Invited Review: Sheep birth distribution in past herds: a review for prehistoric Europe (6th to 3rd millennia BC).

In temperate latitudes sheep have a seasonal reproductive behaviour, which imposes strong constraints on husbandry in terms of work organization and availability of animal products. During the last 50 years, researchers have focused on understanding the mechanisms driving small ruminants' reproduction cycles and finding ways to control them. This characteristic is inherited from their wild ancestor. However, the history of its evolution over the 10 millennia that separates present day European sheep from their Near Eastern ancestors' remains to be written. This perspective echoes archaeologists' current attempts at reconstructing ancient pastoral societies' socio-economical organization. Information related to birth seasonality may be retrieved directly from archaeological sheep teeth. The methodology consists of reconstructing the seasonal cycle record in sheep molars, through sequential analysis of the stable oxygen isotope composition (δ 18O) of enamel. Because the timing of tooth development is fixed within a species, inter-individual variability in this parameter reflects birth seasonality. A review of the data obtained from 10 European archaeological sites dated from the 6th to the 3rd millennia BC is provided. The results demonstrate a restricted breeding season for sheep: births occurred over a period of 3 to 4 months, from late winter to early summer at latitudes 43°N to 48°N, while a later onset was observed at a higher latitude (59°N). All conclusions concurred with currently held expectations based on present day sheep physiology, which, aside from the historical significance, contributes to the reinforcing of the methodological basis of the approach. Further study in this area will permit regional variability attributable to technical choices, within global schemes, to be fully reported.

Macrophage activation and hemophagocytic syndrome in langerhans cell histiocytosis: report of 30 cases.

Macrophage activation and secondary hemophagocytic syndrome are rarely reported in association with Langerhans cell histiocytosis (LCH). The authors reviewed their pathology files for cases of LCH in which evidence of macrophage activation coexisted and report 30 such cases indicating that the association is not that rare and may even be underdiagnosed unless specifically sought. Available clinical data were collected and correlated with pathological findings. Of the 30 cases of LCH with varying degrees of macrophage activation, 29 had multisystem disease. The cases were graded from I to V on the basis of evidence for, and severity of, macrophage activation; cases in category I had evidence of fully developed hemophagocytic syndrome whereas those in category V had limited evidence of macrophage activation. There were seven cases with fully developed hemophagocytic syndrome (category I) and an additional five with hemophagocytosis and some but not all of the features of hemophagocytic syndrome (category II). Most of these 12 cases were young children with high-risk LCH and poor prognosis; 4 are known to have died. Coexisting hemophagocytic syndrome in these cases of LCH may have contributed to their poor prognosis. The association of LCH with macrophage activation, though more than coincidental, is of unknown pathogenesis, but the role of T lymphocytes and cytokines is prominent in both disorders and is presumed to link the two.