The genetic structure of a tribal population, the Yanomama Indians

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65727/1/j.1469-1809.1957.tb01399.x.pd

In Vitro and in Vivo Antioxidant Properties of the Plant-Based Supplement Greens+™

Dietary antioxidants play an important role against oxidation, an underlying mechanism in the incidence of chronic diseases. Greens+ is a commercially available preparation containing a variety of plant-derived ingredients. The aim of the current study was to evaluate the antioxidant potential of the methanolic extract of greens+ powder using in vitro and in vivo techniques. In vitro studies were conducted using a liposome model system to simulate biological cell membranes. Total antioxidant potential and polyphenol content of the herbal preparation was measured. For in vivo analysis, 10 healthy human subjects consumed either three or six teaspoons of greens+ per day for four weeks. Blood samples were analyzed at baseline and at the conclusion of the treatment period for total antioxidant capacity, polyphenol content, protein, lipid and LDL oxidation, and the level of glutathione peroxidase. Results showed that greens+ supplementation was well tolerated and increased serum antioxidant potential at higher levels of intake in a dose-dependent manner. HPLC analysis showed the presence of quercetin, apigenin, kaempferol and luteolin in the supplement. Plasma analysis indicated the presence of kaempferol only. A statistically significant (p < 0.05) reduction in protein and lipid oxidation was observed. Based on its antioxidant properties, the results suggest that greens+ might play a role in reducing the risk of chronic diseases involving a burden of oxidative damage

Phytochemical Screening and Polyphenolic Antioxidant Activity of Aqueous Crude Leaf Extract of Helichrysum pedunculatum

We evaluated the in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extract of Helichrysum pedunculatum. The scavenging activity on superoxide anions, DPPH, H2O2, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extract. The extract exhibited scavenging activity towards all radicals tested due to the presence of relatively high total phenol and flavonoids contents. Our findings suggest that H. pedunculatum is endowed with antioxidant phytochemicals and could serve as a base for future drugs

Effects of prostratin on Cyclin T1/P-TEFb function and the gene expression profile in primary resting CD4(+ )T cells

BACKGROUND: The latent reservoir of human immunodeficiency virus type 1 (HIV-1) in resting CD4(+ )T cells is a major obstacle to the clearance of infection by highly active antiretroviral therapy (HAART). Recent studies have focused on searches for adjuvant therapies to activate this reservoir under conditions of HAART. Prostratin, a non tumor-promoting phorbol ester, is a candidate for such a strategy. Prostratin has been shown to reactivate latent HIV-1 and Tat-mediated transactivation may play an important role in this process. We examined resting CD4(+ )T cells from healthy donors to determine if prostratin induces Cyclin T1/P-TEFb, a cellular kinase composed of Cyclin T1 and Cyclin-dependent kinase-9 (CDK9) that mediates Tat function. We also examined effects of prostratin on Cyclin T2a, an alternative regulatory subunit for CDK9, and 7SK snRNA and the HEXIM1 protein, two factors that associate with P-TEFb and repress its kinase activity. RESULTS: Prostratin up-regulated Cyclin T1 protein expression, modestly induced CDK9 protein expression, and did not affect Cyclin T2a protein expression. Although the kinase activity of CDK9 in vitro was up-regulated by prostratin, we observed a large increase in the association of 7SK snRNA and the HEXIM1 protein with CDK9. Using HIV-1 reporter viruses with and without a functional Tat protein, we found that prostratin stimulation of HIV-1 gene expression appears to require a functional Tat protein. Microarray analyses were performed and several genes related to HIV biology, including APOBEC3B, DEFA1, and S100 calcium-binding protein genes, were found to be regulated by prostratin. CONCLUSION: Prostratin induces Cyclin T1 expression and P-TEFb function and this is likely to be involved in prostratin reactivation of latent HIV-1 proviruses. The large increase in association of 7SK and HEXIM1 with P-TEFb following prostratin treatment may reflect a requirement in CD4(+ )T cells for a precise balance between active and catalytically inactive P-TEFb. Additionally, genes regulated by prostratin were identified that have the potential to regulate HIV-1 replication both positively and negatively

Social Networking Technology, Social Network Composition, and Reductions in Substance Use Among Homeless Adolescents

Peer-based prevention programs for homeless youth are complicated by the potential for reinforcing high-risk behaviors among participants. The goal of this study is to understand how homeless youth could be linked to positive peers in prevention programming by understanding where in social and physical space positive peers for homeless youth are located, how these ties are associated with substance use, and the role of social networking technologies (e.g., internet and cell phones) in this process. Personal social network data were collected from 136 homeless adolescents in Los Angeles, CA. Respondents reported on composition of their social networks with respect to: home-based peers and parents (accessed via social networking technology; e.g., the internet, cell phone, texting), homeless peers and agency staff (accessed face-to-face) and whether or not network members were substance-using or non-substance-using. Associations between respondent’s lifetime cocaine, heroin, and methamphetamine use and recent (previous 30 days) alcohol and marijuana use were assessed by the number of non-substance-using versus substance-using ties in multivariate linear regression models. 43% of adolescents reported a non-substance-using home-based tie. More of these ties were associated with less recent alcohol use. 62% of adolescents reported a substance-using homeless tie. More of these ties were associated with more recent marijuana use as well as more lifetime heroin and methamphetamine use. For homeless youth, who are physically disconnected from positive peers, social networking technologies can be used to facilitate the sorts of positive social ties that effective peer-based prevention programs require

Your space or mine? : Mapping self in time

Peer reviewedPublisher PD

Evaluation of a 'virtual' approach to commissioning health research

BACKGROUND: The objective of this study was to evaluate the implementation of a 'virtual' (computer-mediated) approach to health research commissioning. This had been introduced experimentally in a DOH programme – the 'Health of Londoners Programme' – in order to assess whether is could enhance the accessibility, transparency and effectiveness of commissioning health research. The study described here was commissioned to evaluate this novel approach, addressing these key questions. METHODS: A naturalistic-experimental approach was combined with principles of action research. The different commissioning groups within the programme were randomly allocated to either the traditional face-to-face mode or the novel 'virtual' mode. Mainly qualitative data were gathered including observation of all (virtual and face-to-face) commissioning meetings; semi-structured interviews with a purposive sample of participants (n = 32/66); structured questionnaires and interviews with lead researchers of early commissioned projects. All members of the commissioning groups were invited to participate in collaborative enquiry groups which participated actively in the analysis process. RESULTS: The virtual process functioned as intended, reaching timely and relatively transparent decisions that participants had confidence in. Despite the potential for greater access using a virtual approach, few differences were found in practice. Key advantages included physical access, a more flexible and extended time period for discussion, reflection and information gathering and a more transparent decision-making process. Key challenges were the reduction of social cues available in a computer-mediated medium that require novel ways of ensuring appropriate dialogue, feedback and interaction. However, in both modes, the process was influenced by a range of factors and was not technology driven. CONCLUSION: There is potential for using computer-mediated communication within the research commissioning process. This may enhance access, effectiveness and transparency of decision-making but further development is needed for this to be fully realised, including attention to process as well as the computer-mediated medium

Uncoupling of sexual reproduction from homologous recombination in homozygous Oenothera species

Salient features of the first meiotic division are independent segregation of chromosomes and homologous recombination (HR). In non-sexually reproducing, homozygous species studied to date HR is absent. In this study, we constructed the first linkage maps of homozygous, bivalent-forming Oenothera species and provide evidence that HR was exclusively confined to the chromosome ends of all linkage groups in our population. Co-segregation of complementary DNA-based markers with the major group of AFLP markers indicates that HR has only a minor role in generating genetic diversity of this taxon despite its efficient adaptation capability. Uneven chromosome condensation during meiosis in Oenothera may account for restriction of HR. The use of plants with ancient chromosomal arm arrangement demonstrates that limitation of HR occurred before and independent from species hybridizations and reciprocal translocations of chromosome arms—a phenomenon, which is widespread in the genus. We propose that consecutive loss of HR favored the evolution of reciprocal translocations, beneficial superlinkage groups and ultimately permanent translocation heterozygosity

Hydrophilic antioxidant compounds in orange juice from different fruit cultivars: Composition and antioxidant activity evaluated by chemical and cellular based (Saccharomyces cerevisiae) assays

Antioxidant capacity was evaluated by a cellular model (Saccharomyces cerevisiae) and chemical methods (FRAP, TEAC and total phenols by Folin-Ciocalteu assay) in the hydrophilic fraction (phenolic compounds and ascorbic acid) of orange juices (OJs) from six varieties (Midknight, Delta Seedless, Rohde Red, Seedless, Early and clone Sambiasi), harvested in two seasons. The contents of phenolic compounds and ascorbic acid analyzed, respectively, by UPLC and HPLC were 370.04 76.97 mg/L and 52.05 6.69 mg/100 mL. Variety and season significantly influenced (p < 0.05) composition and antioxidant capacity. TEAC and FRAP values correlated well with individual hydrophilic compounds (R2 > 0.991) but no correlation with cellular assay was observed. An increase in survival rates between 23% and 38% was obtained, excepting for two varieties that showed no activity (Rohde Red and Seedless). Narirutin, naringin-d, ferulic acid-d2, didymin, neoeriocitrin and sinapic acid hexose and caffeic acid-d1 were the phenolic compounds which contributed to survival rates (R2 = 0.979, p < 0.01