Genomic history of coastal societies from eastern South America.

Sambaqui (shellmound) societies are among the most intriguing archaeological phenomena in pre-colonial South America, extending from approximately 8,000 to 1,000 years before present (yr BP) across 3,000 km on the Atlantic coast. However, little is known about their connection to early Holocene hunter-gatherers, how this may have contributed to different historical pathways and the processes through which late Holocene ceramists came to rule the coast shortly before European contact. To contribute to our understanding of the population history of indigenous societies on the eastern coast of South America, we produced genome-wide data from 34 ancient individuals as early as 10,000 yr BP from four different regions in Brazil. Early Holocene hunter-gatherers were found to lack shared genetic drift among themselves and with later populations from eastern South America, suggesting that they derived from a common radiation and did not contribute substantially to later coastal groups. Our analyses show genetic heterogeneity among contemporaneous Sambaqui groups from the southeastern and southern Brazilian coast, contrary to the similarity expressed in the archaeological record. The complex history of intercultural contact between inland horticulturists and coastal populations becomes genetically evident during the final horizon of Sambaqui societies, from around 2,200 yr BP, corroborating evidence of cultural change.

Morphometric affinities and direct radiocarbon dating of the Toca dos Coqueiros' skull (Serra da Capivara, Brazil).

The biological variation of the earliest skeletons of South America has been intensely debated for the last two centuries. One of the major research constraints has been the limited number of available samples dating to the early Holocene. We here present the first direct radiocarbon-date for the early Holocene human skeleton from Toca dos Coqueiros (Serra da Capivara, Brazil), also known as "Zuzu" (8640 ± 30 BP; 9526-9681 cal years BP). We performed craniometric analyses using exclusively samples from Brazil, to revisit the sex of the skeleton, and to discuss the evolutionary processes involved in the occupation of the continent. The sex of the individual was estimated as a female when compared to late and early Holocene individuals, but as a male when compared only to the early Holocene series. We also found that Zuzu presents the strongest differences with the late Holocene Guajajara individuals, located nearby, and the strongest similarities with the early Holocene series from Lagoa Santa, attesting for solid biological affinities among early Holocene individuals from Brazil, as well as a moderate level of morphological variation among them. This suggests that the early individuals were part of the same heterogeneous lineage, possibly a different one from which late Holocene populations diverged.

Ancient Parasite Analysis and Zoonotic Potential of Spirometra sp. in Two Related Sites from Pernambuco, Brazil.

Pathoecology studies the environmental and cultural factors that contribute to the maintenance of infections or diseases in populations. Concerning parasites, it requires the evaluation of these factors based on the presence and life cycle of these organisms. For this reason, it is possible to apply this concept in the context of ancient populations in order to understand the parasite-host dynamic or even the health consequences faced by the members of the populations. This study aimed to apply the pathoecology concept in Pedra do Tubarão and Cemitério do Caboclo archaeological sites. Six coprolite samples were analyzed and 1 was positive for Spirometra sp. eggs. Spirometra is a cestode that has copepods as the first intermediate host; amphibians, reptiles, birds, and mammals as the second intermediate hosts; and felines and canines as definitive hosts. Humans can be infected by ingesting the first or second intermediate hosts and can develop sparganosis, which can cause health consequences depending on the location of the spargana. The presence of this parasite, of a water fount near the site, where the first intermediate host can live, and the findings of the bones of some of the second intermediate hosts in these sites, suggesting dietary purposes, indicate that this infection was probably present in this population.

Social isolation and stress related hormones modulate the stimulating effect of ethanol in preweanling rats.

Preweanling rats are highly sensitive to the locomotor stimulation induced by relatively high ethanol doses. In adult mice this ethanol effect is modulated by stress. The goal of the present study was to analyze the role of stress and corticosterone in the stimulating effect of ethanol in preweanling rats. In Experiment 1 15-day-old rats were separated from the mother during a period of 4h in which subjects remained isolated or paired with a littermate. In a third condition pups remained in the home-cage with the dam. After this isolation period pups were given ethanol (0 or 2.5 g/kg) and were tested in a novel environment. Previous data have shown that a similar period of isolation is enough to increase corticosterone levels in preweanling rats. Experiment 2 evaluated the effect of exogenous administration of corticosterone (0, 3 or 6 mg/kg) along with ethanol, and Experiment 3 tested ethanol-mediated locomotor activation in adrenalectomized preweanling rats. The last experiment aimed to test the role of corticotropic releasing factor 1 (CRF1) receptors in locomotion induced by ethanol in isolated pups. According to our results there is a synergism between stress or corticosterone and ethanol in preweanling rats. The interaction between stress (induced by social isolation) and ethanol seems to be mediated by CRF, since blockade of CRF1 receptors cancelled the effect of ethanol in isolated pups. This study highlights the importance of considering stress as a possible intervening variable in studies evaluating ethanol effects in developing animals when maternal separation is used in the experimental procedure.

Symptoms of insomnia among adolescents in the lower Rio Grande Valley of Texas.

STUDY OBJECTIVES: To estimate the prevalence of symptoms of insomnia among adolescents living along the United States-Mexico border and to examine whether ethnicity and birthplace affect risk for such symptoms. DESIGN: Cross-sectional school-based survey using a version of the 2001 Youth Risk Behavior Survey, modified to elicit data on sleep problems. SETTING: A probability sample of 13 high schools selected from more than 40 high schools in the 4 southernmost counties in Texas-the Lower Rio Grande Valley-contiguous with Mexico. PARTICIPANTS: All ninth-grade students who agreed to participate (n = 5,118). MEASUREMENTS: The sleep module consisted of queries about trouble initiating asleep, trouble maintaining sleep, early morning waking, nonrestorative sleep, quality of sleep, and amount of sleep. RESULTS: Symptoms of insomnia were common, with 12.4% of respondents meeting symptom criteria for insomnia almost every day of the past month. Females were more likely to report insomnia, as were youths reporting lower socioeconomic status. Crude odds ratios suggested foreign-born and those who identified themselves as "Mexican" rather than "Mexican American" were at lower risk of insomnia. However, multivariate analyses eliminated these differences. CONCLUSIONS: More comparative research is needed to ascertain whether and how ethnic culture affects risk for disordered sleep.

P53 codon 72 polymorphism and risk of gastric cancer in a Chinese population.

The p53 gene plays an important role in cell cycle control in response to DNA damage, which may increase the probability of mutations that lead to carcinogenesis. The p53 codon 72 Arg right curved arrow Pro polymorphism has been suggested to be associated with risk for different kind of cancers, but the data on gastric cancer (GC) is very limited. To evaluate the association between this polymorphism and risk of GC, we performed genotype analysis by using a polymerase chain reaction-based restriction fragment length polymorphism assay in a population-based case-control study of 324 GC patients and 317 cancer-free controls in a Chinese population. The controls were frequency-matched to the cases by age, sex and smoking status. The frequency of the p53 Arg allele was 57.4% in the cases and 54.9% in the controls, and the genotype frequencies of p53 Arg/Arg, Arg/Pro, and Pro/Pro were 29.6%, 55.6%, and 14.8%, respectively, in the cases, and 29.6%, 50.5%, and 19.9%, respectively, in the controls (p=0.207). Logistic regression analysis revealed that the p53 Arg allele (Arg/Pro and Arg/Arg genotype) was associated with a borderline significantly increased risk of gastric cancer (adjusted OR=1.44, 95% CI=0.95-2.18), particularly non-cardia gastric cancer (adjusted OR=1.67, 95% CI=1.00-2.77), compared with p53 homozygous Pro allele (Pro/Pro genotype), and the risk was significantly more evident among alcohol drinkers (adjusted OR=2.85, 95% CI=1.37-5.95). While the results suggest that the p53 codon 72 polymorphism may contribute to gastric cancer susceptibility, further larger studies are needed to substantiate our findings and to explore a possible interaction between p53 codon 72 polymorphism and alcohol in the etiology of gastric cancer.