46 research outputs found

    Proliferative and anti-proliferative effects of dietary levels of phytoestrogens in rat pituitary GH3/B6/F10 cells - the involvement of rapidly activated kinases and caspases

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    <p>Abstract</p> <p>Background</p> <p>Phytoestogens are a group of lipophillic plant compounds that can have estrogenic effects in animals; both tumorigenic and anti-tumorigenic effects have been reported. Prolactin-secreting adenomas are the most prevalent form of pituitary tumors in humans and have been linked to estrogen exposures. We examined the proliferative effects of phytoestrogens on a rat pituitary tumor cell line, GH<sub>3</sub>/B<sub>6</sub>/F<sub>10</sub>, originally subcloned from GH<sub>3 </sub>cells based on its ability to express high levels of the membrane estrogen receptor-α.</p> <p>Methods</p> <p>We measured the proliferative effects of these phytoestrogens using crystal violet staining, the activation of several mitogen-activated protein kinases (MAPKs) and their downstream targets via a quantitative plate immunoassay, and caspase enzymatic activities.</p> <p>Results</p> <p>Four phytoestrogens (coumestrol, daidzein, genistein, and <it>trans</it>-resveratrol) were studied over wide concentration ranges. Except <it>trans</it>-resveratrol, all phytoestrogens increased GH<sub>3</sub>/B<sub>6</sub>/F<sub>10 </sub>cell proliferation at some concentration relevant to dietary levels. All four phytoestrogens attenuated the proliferative effects of estradiol when administered simultaneously. All phytoestrogens elicited MAPK and downstream target activations, but with time course patterns that often differed from that of estradiol and each other. Using selective antagonists, we determined that MAPKs play a role in the ability of these phytoestrogens to elicit these responses. In addition, except for <it>trans</it>-resveratrol, a serum removal-induced extrinsic apoptotic pathway was blocked by these phytoestrogens.</p> <p>Conclusion</p> <p>Phytoestrogens can block physiological estrogen-induced tumor cell growth <it>in vitro </it>and can also stimulate growth at high dietary concentrations in the absence of endogenous estrogens; these actions are correlated with slightly different signaling response patterns. Consumption of these compounds should be considered in strategies to control endocrine tumor cell growth, such as in the pituitary.</p

    Effects of rapid urbanisation on the urban thermal environment between 1990 and 2011 in Dhaka Megacity, Bangladesh

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    This study investigates the influence of land-use/land-cover (LULC) change on land surface temperature (LST) in Dhaka Megacity, Bangladesh during a period of rapid urbanisation. LST was derived from Landsat 5 TM scenes captured in 1990, 2000 and 2011 and compared to contemporaneous LULC maps. We compared index-based and linear spectral mixture analysis (LSMA) techniques for modelling LST. LSMA derived biophysical parameters corresponded more strongly to LST than those produced using index-based parameters. Results indicated that vegetation and water surfaces had relatively stable LST but it increased by around 2 °C when these surfaces were converted to built-up areas with extensive impervious surfaces. Knowledge of the expected change in LST when one land-cover is converted to another can inform land planners of the potential impact of future changes and urges the development of better management strategies

    Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

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    Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

    Characterisation of microbial communities within aggressive prostate cancer tissues

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    BACKGROUND: An infectious aetiology for prostate cancer has been conjectured for decades but the evidence gained from questionnaire-based and sero-epidemiological studies is weak and inconsistent, and a causal association with any infectious agent is not established. We describe and evaluate the application of new technology to detect bacterial and viral agents in high-grade prostate cancer tissues. The potential of targeted 16S rRNA gene sequencing and total RNA sequencing was evaluated in terms of its utility to characterise microbial communities within high-grade prostate tumours. METHODS: Two different Massively Parallel Sequencing (MPS) approaches were applied. First, to capture and enrich for possible bacterial species, targeted-MPS of the V2-V3 hypervariable regions of the 16S rRNA gene was performed on DNA extracted from 20 snap-frozen prostate tissue cores from ten "aggressive" prostate cancer cases. Second, total RNA extracted from the same prostate tissue samples was also sequenced to capture the sequence profile of both bacterial and viral transcripts present. RESULTS: Overall, 16S rRNA sequencing identified Enterobacteriaceae species common to all samples and P. acnes in 95% of analyzed samples. Total RNA sequencing detected endogenous retroviruses providing proof of concept but there was no evidence of bacterial or viral transcripts suggesting active infection, although it does not rule out a previous 'hit and run' scenario. CONCLUSIONS: As these new investigative methods and protocols become more refined, MPS approaches may be found to have significant utility in identifying potential pathogens involved in disease aetiology. Further studies, specifically designed to detect associations between the disease phenotype and aetiological agents, are required

    Detection of infectious organisms in archival prostate cancer tissues

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    BACKGROUND: Seroepidemiological studies have reported associations between exposure to sexually transmitted organisms and prostate cancer risk. This study sought DNA evidence of candidate organisms in archival prostate cancer tissues with the aim of assessing if a subset of these cancers show any association with common genital infections. METHODS: 221 archival paraffin-embedded tissue blocks representing 128 histopathologically confirmed prostate cancers comprising 52 "aggressive" (Gleason score ≥ 7) and 76 "non-aggressive" (Gleason score ≤ 6) TURP or radical prostatectomy specimens were examined, as well as unaffected adjacent tissue when available. Representative tissue sections were subjected to DNA extraction, quality tested and screened by PCR for HSV-1, HSV-2, XMRV, BKV, HPV, Chlamydia trachomatis, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma genitalium, and Trichomonas vaginalis. RESULTS: 195 of 221 DNA samples representing 49 "aggressive" and 66 "non-aggressive" prostate cancer cases were suitable for analysis after DNA quality assessment. Overall, 12.2% (6/49) aggressive and 7.6% (5/66) non-aggressive cases were positive for any of the candidate organisms. Mycoplasma genitalium DNA was detected in 4/66 non-aggressive, 5/49 aggressive cancers and in one cancer-unaffected adjacent tissue block of an aggressive case. Ureaplasma urealyticum DNA was detected in 0/66 non-aggressive and 1/49 aggressive cancers and HSV DNA in 1/66 non-aggressive and 0/49 aggressive cancers. This study did not detect BKV, XMRV, T. vaginalis, U. parvum, C. trachomatis or HPV DNA. CONCLUSIONS: The low prevalence of detectable microbial DNA makes it unlikely that persistent infection by the selected candidate microorganisms contribute to prostate cancer risk, regardless of tumour phenotype
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