1,058 research outputs found
Comparison of bacterial culture and 16S rRNA community profiling by clonal analysis and pyrosequencing for the characterization of the dentine caries-associated microbiome
Culture-independent analyses have greatly expanded knowledge regarding the composition of complex bacterial communities including those associated with oral diseases. A consistent finding from such studies, however, has been the under-reporting of members of the phylum Actinobacteria. In this study, five pairs of broad range primers targeting 16S rRNA genes were used in clonal analysis of 6 samples collected from tooth lesions involving dentine in subjects with active caries. Samples were also subjected to cultural analysis and pyrosequencing by means of the 454 platform. A diverse bacterial community of 229 species-level taxa was revealed by culture and clonal analysis, dominated by representatives of the genera Prevotella, Lactobacillus, Selenomonas, and Streptococcus. The five most abundant species were: Lactobacillus gasseri, Prevotella denticola, Alloprevotella tannerae, S. mutans and Streptococcus sp. HOT 070, which together made up 31.6 % of the sequences. Two samples were dominated by lactobacilli, while the remaining samples had low numbers of lactobacilli but significantly higher numbers of Prevotella species. The different primer pairs produced broadly similar data but proportions of the phylum Bacteroidetes were significantly higher when primer 1387R was used. All of the primer sets underestimated the proportion of Actinobacteria compared to culture. Pyrosequencing analysis of the samples was performed to a depth of sequencing of 4293 sequences per sample which were identified to 264 species-level taxa, and resulted in significantly higher coverage estimates than the clonal analysis. Pyrosequencing, however, also underestimated the relative abundance of Actinobacteria compared to culture
Climate effects and stature since 1800
During the last 30 years, economic and social historians have collected and analysed large amounts of anthropometric data in order to explore key aspects of the human past. Attention has also been devoted to the examination of factors that can exert an influence on stature. This article outlines the different ways in which climate might influence stature, either directly or indirectly. It then uses Geographical Information System (GIS) software to explore the relationship between variations in temperature and precipitation and the average heights of men in France, India, Mexico, Spain and the United States (US) over the last two centuries. It is possible to observe an influence of climate on stature in some countries, especially during the nineteenth century, but the relationship weakens across time and largely disappears in recent decades. The attenuation of this relationship is attributed to a process of “technophysio evolution” as countries modernised and developed economically
Female Barrenness, Bodily Access and Aromatic Treatments in Seventeenth-Century England
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, CC BY-NC-ND 3.0 which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made, see https://creativecommons.org/licenses/by-nc-nd/3.0/.Scholars examining medical practice in early modern England have often remarked upon the complexities of the relationship between male physicians and female patients. It has been noted that ideas of female modesty and concern about the potential erotic nature of contact between patients and practitioners could affect the treatment of certain disorders. This paper contributes to this on-going discussion by examining the use of pungent substances to diagnose and treat female barrenness. Diagnostic tests included in medical treatises could rely upon the woman’s ability to perceive a particular substance. These tests thus put women at the centre of the diagnosis of their disorders and allowed them to negotiate access to their reproductive bodies. Similarly medical practitioners included a range of treatments for infertility that involved the fumes of certain substances entering the womb or surrounding the body. These treatments may have allowed women, and perhaps their medical practitioners, to choose a method of remedy that did not involve the application of external lotions to the genitalia. Thus by considering the multi-sensory nature of medical treatment this paper will highlight that the diversity of remedies advocated in early modern medical texts would perhaps have allowed women to restrict access to their reproductive bodies, while still obtaining diagnosis and treatment.Peer reviewe
Fasting Indicators of Insulin Sensitivity: Effects of Ethnicity and Pubertal Status
OBJECTIVE—To examine the relationship of fasting indicators of insulin sensitivity with a more invasive measure of insulin sensitivity (frequently sampled intravenous glucose tolerance test [FSIVGTT]) and the effect of Tanner stage and ethnicity on that relationship. RESEARCHDESIGNANDMETHODS—Data were analyzed from 149 overweight girls (97 Hispanic and 52 African American) who were either in the early stages of maturation defined by Tanner stages 1 or 2 (52Hispanic and 18 African American) or in the later stages of maturation defined by Tanner stages 4 and 5 (45 Hispanic and 34 African American). Fasting indicators of insulin sensitivity (IS) included fasting insulin and glucose and the homeostasis model assess-ment of insulin resistance (HOMA-IR). IS was derived from an FSIVGTTwithminimalmodeling. RESULTS—In Tanner stages 1 and 2, all fasting indicators were significantly associatedwith IS
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Lack of association between PCK1 polymorphisms and obesity, physical activity, and fitness in European Youth Heart Study (EYHS)
Phosphoenolpyruvate carboxykinase-1 (PCK1) is the rate-limiting enzyme in the hepatic gluconeogenic pathway. Studies have shown that overexpression of Pck1 in mice results in obesity-related traits and higher levels of physical activity (PA). Therefore, our aims were to investigate whether common genetic variation in the PCK1 gene influences obesity-related traits, PA, and fitness, and to examine whether PA and fitness attenuate the influence of the PCK1 polymorphisms on obesity in children. Analyses were undertaken on data from Danish and Estonian children (958 boys and 1,104 girls) from the European Youth Heart Study (EYHS), a school-based, cross-sectional study of children (mean ± s.d. age: 9.6 ± 0.4 years) and adolescents (15.5 ± 0.5 years). We genotyped eight polymorphisms that captured the common genetic variations in the PCK1 gene. The association between the PCK1 polymorphisms and BMI, waist circumference (WC), sum of four skinfolds, PA, and fitness was tested using an additive model adjusted for age, age-group, gender, maturity, and country. Interactions were tested by including interaction terms in the model. None of the polymorphisms were significantly associated with BMI, WC, sum of four skinfolds, PA, and fitness, and also with the risk of being overweight or obese (P > 0.05). The interactions between the polymorphisms and age-group, gender, PA, and fitness were not statistically significant. This is the first study to comprehensively examine the association of PCK1 polymorphisms with obesity, PA, and fitness. Despite strong evidence from animal studies, our study in the EYHS cohort failed to identify an association of PCK1 polymorphisms with obesity, PA, and fitness
Trastuzumab-DM1 causes tumour growth inhibition by mitotic catastrophe in trastuzumab-resistant breast cancer cells in vivo
Introduction
Trastuzumab is widely used for the treatment of HER2-positive breast cancer. Despite encouraging clinical results, a significant fraction of patients are, or become, refractory to the drug. To overcome this, trastuzumab-DM1 (T-DM1), a newer, more potent drug has been introduced. We tested the efficacy and mechanisms of action of T-DM1 in nine HER2-positive breast cancer cell lines in vitro and in vivo. The nine cell lines studied included UACC-893, MDA-453 and JIMT-1, which are resistant to both trastuzumab and lapatinib.
Methods
AlamarBlue cell-proliferation assay was used to determine the growth response of breast cancer cell lines to trastuzumab and T-DM1 in vitro. Trastuzumab- and T-DM1-mediated antibody-dependent cellular cytotoxicity (ADCC) was analysed by measuring the lactate dehydrogenase released from the cancer cells as a result of ADCC activity of peripheral blood mononuclear cells. Severe Combined Immunodeficient (SCID) mice were inoculated with trastuzumab-resistant JIMT-1 cells to investigate the tumour inhibitory effect of T-DM1 in vivo. The xenograft samples were investigated using histology and immunohistochemistry.
Results
T-DM1 was strongly growth inhibitory on all investigated HER2-positive breast cancer cell lines in vitro. T-DM1 also evoked antibody-dependent cellular cytotoxicity (ADCC) similar to that of trastuzumab. Outgrowth of JIMT-1 xenograft tumours in SCID mice was significantly inhibited by T-DM1. Histologically, the cellular response to T-DM1 consisted of apoptosis and mitotic catastrophe, the latter evidenced by an increased number of cells with aberrant mitotic figures and giant multinucleated cells.
Conclusions
Our results suggest mitotic catastrophe as a previously undescribed mechanism of action of T-DM1. T-DM1 was found effective even on breast cancer cell lines with moderate HER2 expression levels and cross-resistance to trastuzumab and lapatinib (MDA-453 and JIMT-1).BioMed Central Open acces
Exoplanet Characterization and the Search for Life
Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby
stars. We now hope to conduct a census of all planets around nearby stars and
to characterize their atmospheres and surfaces with spectroscopy. Rocky planets
within their star's habitable zones have the highest priority, as these have
the potential to harbor life. Our science goal is to find and characterize all
nearby exoplanets; this requires that we measure the mass, orbit, and
spectroscopic signature of each one at visible and infrared wavelengths. The
techniques for doing this are at hand today. Within the decade we could answer
long-standing questions about the evolution and nature of other planetary
systems, and we could search for clues as to whether life exists elsewhere in
our galactic neighborhood.Comment: 7 pages, 2 figures, submitted to Astro2010 Decadal Revie
Unusual C35 to C38 alkenones in mid-Holocene sediments from a restricted estuary (Charlotte Harbor, Florida)
Unusual C35 to C38 alkenones were identified in mid-Holocene (8-3.5kyr BP) sediments from a restricted estuary in southwest Florida (Charlotte Harbor). The distribution was dominated by a C36 diunsaturated (ω15,20) ethyl ketone, identical to the one present in Black Sea Unit 2 sediments. Other unus ual alkenones were tentatively assigned as a C35:2 (ω15,20) methyl ketone, a C37:2 (ω17,22) methyl ketone and a C38:2 (ω17,22) ethyl ketone. In late Holocene sediments<3.5kyr BP, the common C37 to C39 alkenones were found. Compound-specific 14C, 13C, and D isotope measurements were used to constrain the possible origin of the alkenones. Conventional radiocarbon ages of alkenones and higher plant-derived long chain n-alcohols indicated no significant difference in age between mid-Holocene alkenones and higher plant n-alcohols. Both alcohols and alkenones were offset vs. calibrated ages of shell fragments in the same sediment core, which suggests they were pre-aged by 500-800yr, implying resuspension and redistribution of the fine-grained sedimentary particles with which they are associated. The hydrogen isotopic (δD) composition (-190‰ to -200‰) of the C37 and C38 alkenones in the late Holocene sediments is in line with values for coastal haptophytes in brackish water. However, the unusual C36 and C38 alkenones from the mid Holocene sediments were enriched in D (by ca. 100‰) vs. the late Holocene alkenones. Also, δ13C values of mid-Holocene alkenones were consistently offset compared with late Holocene alkenones (-21‰ to -22‰ and -22‰ to -23‰, respectively). We suggest that the alkenones in Charlotte Harbor were produced by unknown alkenone-producing haptophyte
Trees increase their P:N ratio with size
Aim: Phosphorus (P) tends to become limiting in ageing terrestrial ecosystems, and its resorption efficiency is higher than for other elements such as nitrogen (N). We thus hypothesized that trees should store more P than those other elements such as N when tree size increases and that this process should be enhanced in slow-growing late-successional trees.- Location: Catalan forests. -Methods: We used data from the Catalan Forest Inventory that contains field data on the P and N contents of total aboveground, foliar and woody biomasses of the diverse mediterranean, temperate and alpine forests of Catalonia (1018 sites). We used correlation and general linear models to analyse the allometric relationships between the nutrient contents of different aboveground biomass fractions (foliar, branches and stems) and total aboveground biomass. - Results: Aboveground forest P content increases proportionally more than aboveground forest N content with increasing aboveground biomass. Two mechanisms underlie this. First, woody biomass increases proportionally more than foliar biomass, with woody biomass having a higher P:N ratio than foliar biomass. Second, the P:N ratio of wood increases with tree size. These results are consistent with the generally higher foliar resorption of P than of N. Slow-growing species accumulate more total P aboveground with size than fast-growing species, mainly as a result of their large capacity to store P in wood. - Main conclusions: Trees may have developed long-term adaptive mechanisms to store P in biomass, mainly in wood, thereby slowing the loss of P from ecosystems, reducing its availability for competitors and implying an increase in the P:N ratio in forest biomass with ageing. This trend to accumulate more P than N with size is more accentuated in slow-growing, large, long-lived species of late successional stages. In this way they partly counterbalance the gradual decrease of P in the soil
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