An early modern human presence in Sumatra 73,000-63,000 years ago.

Genetic evidence for anatomically modern humans (AMH) out of Africa before 75 thousand years ago (ka) and in island southeast Asia (ISEA) before 60 ka (93-61 ka) predates accepted archaeological records of occupation in the region. Claims that AMH arrived in ISEA before 60 ka (ref. 4) have been supported only by equivocal or non-skeletal evidence. AMH evidence from this period is rare and lacks robust chronologies owing to a lack of direct dating applications, poor preservation and/or excavation strategies and questionable taxonomic identifications. Lida Ajer is a Sumatran Pleistocene cave with a rich rainforest fauna associated with fossil human teeth. The importance of the site is unclear owing to unsupported taxonomic identification of these fossils and uncertainties regarding the age of the deposit, therefore it is rarely considered in models of human dispersal. Here we reinvestigate Lida Ajer to identify the teeth confidently and establish a robust chronology using an integrated dating approach. Using enamel-dentine junction morphology, enamel thickness and comparative morphology, we show that the teeth are unequivocally AMH. Luminescence and uranium-series techniques applied to bone-bearing sediments and speleothems, and coupled uranium-series and electron spin resonance dating of mammalian teeth, place modern humans in Sumatra between 73 and 63 ka. This age is consistent with biostratigraphic estimations, palaeoclimate and sea-level reconstructions, and genetic evidence for a pre-60 ka arrival of AMH into ISEA. Lida Ajer represents, to our knowledge, the earliest evidence of rainforest occupation by AMH, and underscores the importance of reassessing the timing and environmental context of the dispersal of modern humans out of Africa.

Pleistocene cave art from Sulawesi, Indonesia.

Archaeologists have long been puzzled by the appearance in Europe ∼40-35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines), and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia, where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ∼40 kyr ago at opposite ends of the Pleistocene Eurasian world.

Immune and metabolic effects of arginine in the surgical patient.

Arginine enhances immune function and promotes nitrogen retention in animal models, but its immunomodulatory effects in surgical patients are unknown. This randomized, prospective trial evaluated the immune and metabolic effects of supplemental L-arginine (25 g/day, n = 16) or isonitrogenous L-glycine (43 g/day, n = 14) in 30 cancer patients undergoing major operation. Two groups of patients received either arginine or glycine for 7 days after surgery as a supplement to a graduated enteral diet. Nitrogen balance was measured daily, and immune parameters were determined both before and after surgery, on Days 1, 4, and 7. The T-lymphocyte response to concanavalin A (con A) and PHA and dual marker phenotype analysis of lymphocyte (CD2, CD4, CD4/DR, CD8, CD8/DR) and macrophage (M3/DR) subsets were determined. Mean age, degree of preoperative weight loss, disease stage, number of perioperative transfusions, and calorie and nitrogen intake were similar for the groups studied. Mean daily nitrogen balance (-2.3 g/day in the arginine group vs. -3.9 g/day in the glycine group) was not significantly different between the two groups, but positive mean nitrogen balance was achieved only in the arginine group between Days 5 and 7 after surgery. Supplemental arginine significantly enhanced the mean T-lymphocyte response (stimulation index) to con A from 45 +/- 26 on postoperative Day 1 to 72 +/- 47 and 87 +/- 49 on postoperative Days 4 and 7, compared with the values of 29 +/- 15, 27 +/- 20, and 33 +/- 34 in the glycine group at the same time points, respectively. Supplemental arginine increased mean CD4 phenotype (% T-cells) on postoperative Days 1 and 7 from 25 +/- 9 to 43 +/- 14, compared with the values of 30 +/- 14 and 29 +/- 13 in the glycine group (p less than 0.05). The beneficial effect of arginine on the immune system appeared distinct from its more moderate effect on nitrogen metabolism. As a nutrient substrate, arginine was nontoxic, and may benefit surgical patients who are at increased risk of infection.