<i>Ceramium botryocarpum</i> and <i>C. secundatum</i> re-evaluated

In the British Isles the genus Ceramium is represented by 15 species, divided into to groups. The two groups without cortical spines are (1) fully corticated species and (2) those with ecorticated internodes. Group 1 species are very difficult to distinguish. In particular the key morphological features that discriminate between C. botryocarpum and C. secundatum include the number of periaxial cells and presence of adventitious branching (Maggs and Hommersand, 1993). However, these features may be influenced by the environment. By using various molecular markers, growing cultures in different conditions and crossing experiments we aim to clarify the relationship between the species of group 1.Analysis of the formalin preserved vouchers showed that C. botryocarpum and C. secundatum are morphologically almost identical. They only differ in the number of periaxial cells (6-7 for C. botryocarpum and 7-8 for C. secundatum) and by the more robust, larger thallus of C. secundatum. Culture studies showed that the morphology of Ceramium is highly influenced by the environment. There was crossing with formation of tetrasporophytes between C. botryocarpum and C. secundatum. The phylogenetic analysis with the chloroplast marker (tufA/rpl31) and the mitochondrial marker (cox2-3 spacer, Gabrielsen 2002) clearly demonstrate that C. botryocarpum and C. secundatum are not respectively monophyletic. Analysis of multiple samples and with different techniques confirmed that C. botryocapum Griffiths ex Harvey (1848) is a later synonym of C. secundatum Lyngbye (1819)

Sex Differences and Cognitive Maps: Studies in the Lab don’t Always Reflect Cognitive Map Accuracy in Everyday Life

The ability to create an accurate mental survey representation, or cognitive map, when moving through an environment varies widely across individuals, and we are still trying to understand the origins of these individual differences. Non-immersive virtual environments used to test for cognitive map accuracy in the laboratory have shown sex differences with a performance advantage for men in some studies but not others. When sex differences are demonstrated, it is unclear whether women’s performance generalizes to familiar and unfamiliar real-world environments. In Experiment 1, 98 participants explored the virtual environment Silcton and afterwards estimated directions between the landmarks in Silcton and arranged landmarks found in Silcton on a map. In addition, they reported frequently visited real-world locations and then estimated directions between them and drew a map of the locations. Men were more accurate on tests of Silcton than women were, although there was no difference between sexes for accuracy with real-world locations. Within sexes, women were more accurate with the real-world locations than Silcton, while men showed the opposite pattern. In Experiment 2, 21 women were tested with Silcton and their familiar real-world locations as in Experiment 1 but were also walked through an unfamiliar real-world area on campus and completed direction estimation and map drawing tests for the new environment. Overall, women were more accurate with the two real-world environments than Silcton, with some evidence that accuracy with the new real-world environment was more accurate than the familiar real-world locations. Overall, women’s ability to create a cognitive map of a virtual environment in the laboratory does not seem to be indicative of their ability to do the same in the real world, and care should be taken when generalizing lab results with virtual environments

Hunting for nuclear markers in green algal lineages: molecular evolution of glucose-6-phosphate isomerase

The Chlorophyta exhibit a remarkable cytological diversity ranging from unicellular microscopic algae with a single nucleus, over multicellular filaments and foliose blades, to coencytic and even siphonous life forms that are essentially composed of a giant cell containing thousands of nuclei. Unravelling the evolutionary history of this diverse and evolutionary old group is a difficult task due to the antiquity of the major lineages and considerable rate variation between those lineages for the commonly used 18S ribosomal DNA sequences and chloroplast markers (Lewis et al., Therefore different genes with known function and sequence data available are tested and more recently a cDNA library is screened to search for new useful genes.Glucose-6-phosphate isomerase (G6PI) is one of the genes we are testing. It is an important enzyme of the carbohydrate biosynthesis pathway in photosynthetic organisms and of the glycolysis in all organisms. Little is known about copy number of the gene in the Chlorophyta. The complete genome sequences of Chlamydomonas reinhardtii and Ostreococcus taur revealed that both have a single copy of G6PI. In plants however within a single genus there are species with one G6PI gene and other species with two G6PI (e.g. Arabidopsis, Actinidia,…) and up to thre copies are observed in Zea mays. It always concerns recent duplication within one genus.To investigate if the G6PI gene(s) is useful as a phylogenetic marker in the Chlorophyta, primers were made based on the G6PI genome sequences of Arabidopsis thaliana, Oryza sativa, Chlamydomonas reinhardtii and Ostreococcus tauri. The primers were tested on DNA and RNA of a variety of green algae.Following conclusions can be drawn from these preliminary results: 1. epiphytic or endophytic bacteria interfere with the direct amplification of nuclear genes; 2. the G6PI gene is informative on several taxonomic levels: for deep phylogenies we have to use a codon substitution model, for species level relationships introns may offer opportunities towards studies at the interspecific level; 3. most likely only one (functional) copy of the G6PI gene is present in the tested taxa

Conservation of diatom biodiversity: issues and prospects

The diatoms are microscopic unicellular plants, which in spite of their tiny size (normally within the range of 0.01-0.1 mm) play an enormous role in the functioning of the biosphere. Their contribution to the global production of organic matter created on Earth through photosynthesis is estimated as 20-25%. Very recently, the results of sensitive, fine-grained taxonomical, biological and biogeographical studies have provided strong evidence that the widely accepted dogma that microorganisms are predominantly cosmopolitan does not apply in case of the diatoms. Many diatom species may be endemics and some of them seem to be restricted to a small geographical area, which makes conservation of diatoms a significant issue. It is time to realise that efforts to develop realistic conservation strategies for aquatic environments, both at the local and global scale should include the diatoms and possibly also other groups of microorganisms. Some ways of how the diatoms could be involved in this process are presented for discussion

The Relevance of Breast Cancer Subtypes in the Outcome of Neoadjuvant Chemotherapy

BACKGROUND: Breast cancer is increasingly considered a heterogeneous disease. The aim of this study was to assess the differences between histological and receptor-based subtypes in breast-conserving surgery and pathological complete response (pCR) after neoadjuvant chemotherapy. METHOD: A consecutive series of 254 patients with operable breast cancer treated with neoadjuvant chemotherapy was analyzed. Tumors were classified according to their receptor status in estrogen receptor (ER)-positive tumors (HER2-negative), triple-negative tumors, and HER2-positive tumors. The type of surgery feasible prior to neoadjuvant chemotherapy was compared with the actual surgery performed. RESULTS: The overall increase in breast-conserving surgery was 37% (73 of 198). In patients with ductal and lobular carcinomas this increase was 41% (63 of 152, 95% confidence interval [95% CI] 0.34-0.49) and 20% (7 of 35, 95% CI 0.10-0.36), respectively (P = 0.02). Half of the patients with lobular carcinoma had to undergo a secondary mastectomy because of incomplete resection margins. In ER-positive, triple-negative and HER2-positive tumors, the increase in breast-conserving surgery was 39% (42 of 109, 95% CI 0.30-0.48), 24% (11 of 45, 95% CI 0.14-0.38), and 45% (20 of 44, 95% CI 0.32-0.60) (P = 0.11). The pCR rate in ductal and lobular carcinomas was 12% (23 of 195) and 2% (1 of 42), respectively (P = 0.09). In ER-positive, triple-negative and HER2-positive tumors the pCR rates were 2% (3 of 138), 28% (16 of 57), and 18% (10 of 56), respectively. Multivariate analysis showed that the receptor-based subtype was the only significant predictor of pCR (P = 0.004). CONCLUSION: In lobular tumors the benefit with regard to breast-conserving surgery of neoadjuvant chemotherapy is questionable. Although in ER-positive tumors the pCR rate is low, the increase in breast-conserving surgery was remarkable in ductal ER-positive tumor

The value of diffusion-weighted imaging in assessing the ADC changes of tissues adjacent to breast carcinoma

<p>Abstract</p> <p>Background</p> <p>To define a threshold value of apparent diffusion coefficient (ADC) with which malignant breast lesions can be distinguished from benign lesions, and to evaluate the ADC change of peri-tumor tissue in breast carcinoma by echo planar-diffusion weighted imaging (EPI-DWI).</p> <p>Methods</p> <p>57 breast lesions were scanned by routine MRI and EPI-DWI. The ADC values were compared between malignant and benign lesions. The sensitivity and specificity of EPI-DWI and the threshold ADC value were evaluated by Receiver Operating Characteristic curve (ROC). The ADC values of malignant lesion and layered peri-tumor tissues (from innermost layer 1 to outermost layer 4 with 5 mm every layer) in different directions were compared and the ADC values among different layers were compared.</p> <p>Results</p> <p>The ADC value of 35 malignant lesions was statistically lower than that of 22 benign lesions (P < 0.05). In ROC curve, the threshold value was 1.24 +/- 0.25*10E-3 mm²/s (b = 500) or 1.20 +/- 0.25*10E-3 mm²/s (b = 1000). The ADC value of malignant lesions was statistically lower than that of peri-tumor tissues in different directions (P < 0.05). For peri-tumor tissues, the ADC values increased gradually from layer 1 to layer 4 and there was a significant difference between the ADC values of layer 1 and layer 2 (P < 0.05); while from layer 2 outwards, there was no statistical difference among different layers.</p> <p>Conclusion</p> <p>ADC value was a sensitive and specific parameter that could help to differentiate benign and malignant breast lesions. ADC changes in tissues adjacent to breast carcinoma could be detected by EPI-DWI, which made EPI-DWI a promising method for helping to determine surgical scope of breast carcinoma.</p

Cost-effectiveness of early detection of breast cancer in Catalonia (Spain)

<p>Abstract</p> <p>Background</p> <p>Breast cancer (BC) causes more deaths than any other cancer among women in Catalonia. Early detection has contributed to the observed decline in BC mortality. However, there is debate on the optimal screening strategy. We performed an economic evaluation of 20 screening strategies taking into account the cost over time of screening and subsequent medical costs, including diagnostic confirmation, initial treatment, follow-up and advanced care.</p> <p>Methods</p> <p>We used a probabilistic model to estimate the effect and costs over time of each scenario. The effect was measured as years of life (YL), quality-adjusted life years (QALY), and lives extended (LE). Costs of screening and treatment were obtained from the Early Detection Program and hospital databases of the IMAS-Hospital del Mar in Barcelona. The incremental cost-effectiveness ratio (ICER) was used to compare the relative costs and outcomes of different scenarios.</p> <p>Results</p> <p>Strategies that start at ages 40 or 45 and end at 69 predominate when the effect is measured as YL or QALYs. Biennial strategies 50-69, 45-69 or annual 45-69, 40-69 and 40-74 were selected as cost-effective for both effect measures (YL or QALYs). The ICER increases considerably when moving from biennial to annual scenarios. Moving from no screening to biennial 50-69 years represented an ICER of 4,469€ per QALY.</p> <p>Conclusions</p> <p>A reduced number of screening strategies have been selected for consideration by researchers, decision makers and policy planners. Mathematical models are useful to assess the impact and costs of BC screening in a specific geographical area.</p

Risk factors for ductal and lobular breast cancer: results from the nurses' health study

Introduction Ductal and lobular carcinomas are the two most common types of invasive breast cancer. Whether well-established risk factors are differentially associated with risk on the basis of histologic subtype is not clear. We prospectively investigated the association between a number of hormonal and nonhormonal exposures and risk defined by histologic subtype among 4,655 ductal and 659 lobular cases of postmenopausal breast cancer from the Nurses\u27 Health Study. Methods Multivariate Cox proportional hazards regression stratified by histologic subtype and time period was used to examine the association between risk factors and the incidence of ductal and lobular subtypes. For each exposure, we calculated the P value for heterogeneity using a likelihood ratio test comparing models with separate estimates for the two subtypes versus a single estimate across subtypes. Results The associations with age at menarche (P-heterogeneity (het) = 0.03), age at first birth (P-het \u3c 0.001) and postmenopausal hormone use (P-het \u3c 0.001) were more strongly associated with lobular cancers. The associations with age, nulliparity, parity, age at menopause, type of menopause, alcohol intake, adult body mass index (BMI), BMI at age 18, family history of breast cancer and personal history of benign breast disease did not vary by subtype (P-het ≥ 0.08). Results were similar when we restricted the analyses to estrogen receptor-positive and progesterone receptor-positive tumors. Conclusions These data indicate that breast cancer is a heterogeneous disease, and the differential association with a number of risk factors is suggestive of etiologically distinct tumors. Epidemiological analyses should continue to take into account a modifying role of histology

The GC-Rich Mitochondrial and Plastid Genomes of the Green Alga Coccomyxa Give Insight into the Evolution of Organelle DNA Nucleotide Landscape

Most of the available mitochondrial and plastid genome sequences are biased towards adenine and thymine (AT) over guanine and cytosine (GC). Examples of GC-rich organelle DNAs are limited to a small but eclectic list of species, including certain green algae. Here, to gain insight in the evolution of organelle nucleotide landscape, we present the GC-rich mitochondrial and plastid DNAs from the trebouxiophyte green alga Coccomyxa sp. C-169. We compare these sequences with other GC-rich organelle DNAs and argue that the forces biasing them towards G and C are nonadaptive and linked to the metabolic and/or life history features of this species. The Coccomyxa organelle genomes are also used for phylogenetic analyses, which highlight the complexities in trying to resolve the interrelationships among the core chlorophyte green algae, but ultimately favour a sister relationship between the Ulvophyceae and Chlorophyceae, with the Trebouxiophyceae branching at the base of the chlorophyte crown