Origin and environmental setting of ancient agriculture in the lowlands of Mesoamerica.

Archaeological research in the Gulf Coast of Tabasco reveals the earliest record of maize cultivation in Mexico. The first farmers settled along beach ridges and lagoons of the Grijalva River delta. Pollen from cultivated Zea appears with evidence of forest clearing about 5100 calendar years B.C. (yr B.C.) [6200 (14)C years before the present (yr B.P.)]. Large Zea sp. pollen, typical of domesticated maize (Zea mays), appears about 5000 calendar yr B.C. (6000 yr B.P.). A Manihot sp. pollen grain dated to 4600 calendar yr B.C. (5800 yr B.P.) may be from domesticated manioc. About 2500 calendar yr B.C. (4000 yr B.P.), domesticated sunflower seeds and cotton pollen appear as farming expanded.

Bilateral renal vein thrombosis and venous sinus thrombosis in a neonate with factor V mutation (FV Leiden).

Bilateral renal vein thrombosis and venous sinus thrombosis were diagnosed within 3 weeks of birth in a full-term neonate. Heterozygosity for a factor V mutation leading to resistance against the anticoagulatory properties of activated protein C was found. Heparin therapy led to resolution of the thrombotic manifestations. With long-term oral anticoagulation, no relapse or other thrombotic event occurred during infancy.