Abstinence-only education and teen pregnancy rates: why we need comprehensive sex education in the U.S

The United States ranks first among developed nations in rates of both teenage pregnancy and sexually transmitted diseases. In an effort to reduce these rates, the U.S. government has funded abstinence-only sex education programs for more than a decade. However, a public controversy remains over whether this investment has been successful and whether these programs should be continued. Using the most recent national data (2005) from all U.S. states with information on sex education laws or policies (N = 48), we show that increasing emphasis on abstinence education is positively correlated with teenage pregnancy and birth rates. This trend remains significant after accounting for socioeconomic status, teen educational attainment, ethnic composition of the teen population, and availability of Medicaid waivers for family planning services in each state. These data show clearly that abstinence-only education as a state policy is ineffective in preventing teenage pregnancy and may actually be contributing to the high teenage pregnancy rates in the U.S. In alignment with the new evidence-based Teen Pregnancy Prevention Initiative and the Precaution Adoption Process Model advocated by the National Institutes of Health, we propose the integration of comprehensive sex and STD education into the biology curriculum in middle and high school science classes and a parallel social studies curriculum that addresses risk-aversion behaviors and planning for the future.     

Poor trail making test performance is directly associated with altered dual task prioritization in the elderly--baseline results from the TREND study

Background

Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance—which specifically measures cognitive flexibility and working memory—and dual task costs, a measure of prioritization.

Methodology and Principal Findings

Out of the TREND study (Tuebinger evaluation of Risk factors for Early detection of Neurodegenerative Disorders), 686 neurodegeneratively healthy, non-demented elderly aged 50 to 80 years were classified according to their Trail Making Test performance (delta TMT; TMT-B minus TMT-A). The subjects performed 20 m walks with habitual and maximum speed. Dual tasking performance was tested with walking at maximum speed, in combination with checking boxes on a clipboard, and subtracting serial 7 s at maximum speeds. As expected, the poor TMT group performed worse when subtracting serial 7 s under single and dual task conditions, and they walked more slowly when simultaneously subtracting serial 7 s, compared to the good TMT performers. In the walking when subtracting serial 7 s condition but not in the other 3 conditions, dual task costs were higher in the poor TMT performers (median 20%; range −6 to 58%) compared to the good performers (17%; −16 to 43%; p<0.001). To the contrary, the proportion of the poor TMT performance group that made calculation errors under the dual tasking situation was lower than under the single task situation, but higher in the good TMT performance group (poor performers, −1.6%; good performers, +3%; p = 0.035).

Conclusion

Under most challenging conditions, the elderly with poor TMT performance prioritize the cognitive task at the expense of walking velocity. This indicates that poor cognitive flexibility and working memory are directly associated with altered prioritization.     

Reduced food intake and body weight in mice deficient for the G protein-coupled receptor GPR82

G protein-coupled receptors (GPCR) are involved in the regulation of numerous physiological functions. Therefore, GPCR variants may have conferred important selective advantages during periods of human evolution. Indeed, several genomic loci with signatures of recent selection in humans contain GPCR genes among them the X-chromosomally located gene for GPR82. This gene encodes a so-called orphan GPCR with unknown function. To address the functional relevance of GPR82 gene-deficient mice were characterized. GPR82-deficient mice were viable, reproduced normally, and showed no gross anatomical abnormalities. However, GPR82-deficient mice have a reduced body weight and body fat content associated with a lower food intake. Moreover, GPR82-deficient mice showed decreased serum triacylglyceride levels, increased insulin sensitivity and glucose tolerance, most pronounced under Western diet. Because there were no differences in respiratory and metabolic rates between wild-type and GPR82-deficient mice our data suggest that GPR82 function influences food intake and, therefore, energy and body weight balance. GPR82 may represent a thrifty gene most probably representing an advantage during human expansion into new environments.     

Phylogenetic biogeography of the leafy liverwort Herbertus (Jungermanniales, Herbertaceae) based on nuclear and chloroplast DNA sequence data: correlation between genetic variation and geographical distribution

Aim The cosmopolitan genus Herbertus is notorious for having a difficult taxonomy and for the fact that there is limited knowledge of species ranges and relationships. Topologies generated from variable molecular markers are used to discuss biogeographical patterns in Herbertus and to compare them with the geological history of continents and outcomes reported for other land plants. Location Africa, Asia, Azores, Europe, southern South America, northern South America, North America, New Zealand. Methods Phylogenetic analyses of nuclear ribosomal internal transcribed spacer and chloroplast (cp) trnL–trnF sequences of 66 accessions of Herbertus and the outgroup species Triandrophyllum subtrifidum and Mastigophora diclados were used to investigate biogeographical patterns in Herbertus. Areas of putative endemism were defined based on the distribution of species included in the analyses. Maximum parsimony analyses were undertaken to reconstruct ancestral areas and intraspecies migration routes. Results The analyses reveal species‐level cladograms with a correlation between genetic variation and the geographical distribution of the related accessions. The southern South American Herbertus runcinatus is sister to the remainder of the genus, which is split into two main clades. One contains the Neotropical–African Herbertus juniperoideus and the New Zealand/Tasmanian Herbertus oldfieldianus. An African accession of H. juniperoideus is nested within Neotropical accessions. The second main clade includes species that inhabit Asia, the Holarctic, Africa, and northern South America. Maximum parsimony analyses indicate that this clade arose in Asia. Herbertus sendtneri originated in Asia and subsequently colonized the Holarctic and northern South America. An Asian origin and colonization into Africa is indicated for H. dicranus. Main conclusions The current distribution of Herbertus cannot be explained by Gondwanan vicariance. A more feasible explanation of the range is a combination of short‐distance dispersal, rare long‐distance dispersal events (especially into regions that faced floral displacements as a result of climatic changes) extinction, recolonization, and diversification. The African Herbertus flora is a mixture of Asian and Neotropical elements. Southern South America harbours an isolated species. The molecular data indicate partial decoupling of molecular and morphological variation in Herbertus. Biogeographical patterns in Herbertus are not dissimilar to those of other groups of bryophytes, but elucidation of the geographical ranges requires a molecular approach. Some patterns could be the result of maintenance of Herbertus in the inner Tropics during glacial maxima, and dispersal into temperate regions in warm phases.     

Optimization of the differentiation of human preadipocytes in vitro

This study aimed at developing an optimal protocol for proliferation and differentiation of preadipocytes that is a prerequisite for constructing an ideal biohybrid composed of viable adipose precursor cells in a three-dimensional matrix. Such an implant could represent an adequate solution for correcting soft tissue defects, e.g., extensive deep burns or tumor resections. Preadipocytes were isolated from human subcutaneous adipose tissue samples and cultured in Dulbecco's modified eagle medium (DMEM)/Ham's F12 medium (F12) or OPTIMEM medium with or without the addition of human serum (hS) or fetal calf serum (FCS). The advantages of fibronectin-coated culture dishes for preadipocyte yield after isolation and differentiation were evaluated. After culture expansion, differentiation was induced by insulin, isobutylmethylxanthine, pioglitazone, dexamethasone, and transferrin in the absence of serum. The extent of differentiation was assayed by measuring the activity of glycerophosphate dehydrogenase as well as counting of differentiated versus undifferentiated cells. Our results show that fibronectin coating does not only strongly increase the yield of preadipocytes after isolation from adipose tissue but also significantly enhances differentiation of precursor cells to mature adipocytes. For optimal cell expansion, DMEM/F12 is more promoting than OPTIMEM and culturing with FCS shows a slightly better proliferation compared with hS supplementation. Differentiation, in contrast, is significantly improved when hS is used instead of FCS during proliferation. Our results smooth the way for autologous preadipocyte culturing and show that hS for preadipocyte culturing opens new and promising perspectives for adipose tissue engineering by optimizing in vitro expansion in cell culture and inducing substantial differentiation.     

Development of PCR primers specific for the amplification and direct sequencing of gyrB genes from microbacteria, order Actinomycetales

PCR primer sets were developed for the specific amplification and sequence analyses encoding the gyrase subunit B (gyrB) of members of the family Microbacteriaceae, class Actinobacteria. The family contains species highly related by 16S rRNA gene sequence analyses. In order to test if the gene sequence analysis of gyrB is appropriate to discriminate between closely related species, we evaluate the 16S rRNA gene phylogeny of its members. As the published universal primer set for gyrB failed to amplify the responding gene of the majority of the 80 type strains of the family, three new primer sets were identified that generated fragments with a composite sequence length of about 900 nt. However, the amplification of all three fragments was successful only in 25% of the 80 type strains. In this study, the substitution frequencies in genes encoding gyrase and 16S rDNA were compared for 10 strains of nine genera. The frequency of gyrB nucleotide substitution is significantly higher than that of the 16S rDNA, and no linear correlation exists between the similarities of both molecules among members of the Microbacteriaceae. The phylogenetic analyses using the gyrB sequences provide higher resolution than using 16S rDNA sequences and seem able to discriminate between closely related species.     

Calcitonin gene related peptide mediates cardioprotection by remote preconditioning

Excitation of sensory nerves and activation of myocardial protein kinase C (PKC) epsilon contribute to the transduction of remote preconditioning (RPC) to the heart. Since calcitonin gene related peptide (CGRP) is an important mediator of sensory neurons we tried to delineate whether CGRP a) protects the heart from ischemic injury, b) is involved in cardioprotection after RPC, and c) leads to an activation of myocardial PKCepsilon. RPC was achieved by brief mesenteric artery occlusion followed by reperfusion. Myocardial infarct size (IS) was measured by TTC staining after temporary coronary artery occlusion (CAO) in rats. CGRP plasma levels were determined by radioimmunoassay and PKCepsilon was measured by quantitative immunoblotting. CGRP infusion reduced infarct size by 57%, an action that was abolished after co-treatment with the PKC inhibitor chelerythrine. RPC significantly increased CGRP plasma levels, reduced infarct size, and activated myocardial PKCepsilon. Infarct size reduction was abolished and PKCepsilon activation was significantly attenuated by CGRP(8-37), a specific CGRP receptor antagonist. Ganglion blockade with hexamethonium did not influence CGRP release by RPC but abolished CGRP mediated myocardial PKCepsilon activation. In conclusion, CGRP protects the heart from ischemic injury and is involved in RPC, presumably by activating myocardial PKCepsilon.     

Interaction of hypohalous acids and heme peroxidases with unsaturated phosphatidylcholines

The formation of chlorohydrins, bromohydrins, and iodohydrins from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) by the myeloperoxidase-hydrogen peroxide-halide system was evaluated by means of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry. This approach allows to detect different kinds of the halogenation reaction even in one mass spectrum. Using a mixture of Cl-, Br-, I-, and SCN- at physiological concentrations, a bromination of POPC dominates by the MPO-hydrogen peroxide-halide system. Hypothiocyanite does apparently not react with the double bond of POPC, but increasing amounts of SCN- cause a decrease of the bromohydrin peaks. An interconversion between different hypohalous acids produced by the myeloperoxidase-hydrogen peroxide-halide system determines the pattern of halogenohydrins in POPC. Especially, hypochlorous acid is able to oxidise Br- to hypobromous acid.