398 research outputs found
Competitive endothelial adhesion between Plasmodium falciparum isolates under physiological flow conditions
<p>Abstract</p> <p>Background</p> <p>Sequestration of parasitized red blood cells in the microvasculature of major organs involves a sequence of events that is believed to contribute to the pathogenesis of severe falciparum malaria. <it>Plasmodium falciparum </it>infections are commonly composed of multiple subpopulations of parasites with varied adhesive properties. A key question is: do these subpopulations compete for adhesion to endothelium? This study investigated whether, in a laboratory model of cytoadherence, there is competition in binding to endothelium between pRBC infected with <it>P. falciparum </it>of variant adhesive phenotypes, particularly under flow conditions.</p> <p>Methods</p> <p>Four different <it>P. falciparum </it>isolates, of known adherence phenotypes, were matched in pairs, mixed in different proportions and allowed to bind to cultured human endothelium. Using <it>in vitro </it>competitive static and flow-based adhesion assays, that allow simultaneous testing of the adhesive properties of two different parasite lines, adherence levels of paired <it>P. falciparum </it>isolates were quantified and analysed using either non-parametric Wilcoxon's paired signed rank test or Student paired test.</p> <p>Results</p> <p>Study findings show that <it>P. falciparum </it>parasite lines show marked differences in the efficiency of adhesion to endothelium.</p> <p>Conclusion</p> <p><it>Plasmodium falciparum </it>variants will compete for adhesion to endothelia and variants can be ranked by their efficiency of binding. These findings suggest that variants from a mixed infection will not show uniform cytoadherence and so may vary in their ability to cause disease.</p
Nitrogen forms affect root structure and water uptake in the hybrid poplar
The study analyses the effects of two different forms of nitrogen fertilisation (nitrate and ammonium) on root structure and water uptake of two hybrid poplar (Populus maximowiczii x P. balsamifera) clones in a field experiment. Water uptake was studied using sap flow gauges on individual proximal roots and coarse root structure was examined by excavating 18 whole-root systems. Finer roots were scanned and analyzed for architecture. Nitrogen forms did not affect coarse-root system development, but had a significant effect on fine-root development. Nitrate-treated trees presented higher fine:coarse root ratios and higher specific root lengths than control or ammonium treated trees. These allocation differences affected the water uptake capacity of the plants as reflected by the higher sapflow rate in the nitrate treatment. The diameter of proximal roots at the tree base predicted well the total root biomass and length. The diameter of smaller lateral roots also predicted the lateral root mass, length, surface area and the number of tips. The effect of nitrogen fertilisation on the fine root structure translated into an effect on the functioning of the fine roots forming a link between form (architecture) and function (water uptake)
Influence of oral beclomethasone dipropionate on early non-infectious pulmonary outcomes after allogeneic hematopoietic cell transplantation: results from two randomized trials.
Early non-infectious pulmonary complications represent a significant cause of mortality after hematopoietic cell transplantation (HCT). We tested the hypothesis that oral beclomethasone dipropionate (BDP) is effective for preventing early non-infectious pulmonary complications after allogeneic HCT. We retrospectively reviewed the medical records of 120 patients, 60 in each treatment arm, to identify non-infectious and infectious pulmonary events and pulmonary function test results from all patients who participated in two randomized trials of oral BDP for treatment of acute gastrointestinal GVHD. 17-Beclomethasone monopropionate (17-BMP), the active metabolite of BDP, was evaluated in blood from the right atrium in four patients. Thirty-three of 42 (79%) placebo-treated patients experienced a decrease of the DL(CO) from pretransplant to day 80 after transplant, compared with 27 of 49 (55%) BDP-treated patients (P=0.02). In the first 200 days after randomization, there were no cases of non-infectious pulmonary complications in BDP-treated patients, vs four cases among placebo-treated patients (P=0.04). Levels of 17-BMP were detected in atrial blood at steady state. Delivery of a potent glucocorticoid such as 17-BMP to the pulmonary artery after oral dosing of BDP may be useful in modulating pulmonary inflammation and preventing the development of non-infectious pulmonary complications after allogeneic HCT.Bone Marrow Transplantation advance online publication, 29 June 2009; doi:10.1038/bmt.2009.129
Molecular Detection of Multiple Emerging Pathogens in Sputa from Cystic Fibrosis Patients
Background: There is strong evidence that culture-based methods detect only a small proportion of bacteria present in the respiratory tracts of cystic fibrosis (CF) patients. Methodology/Principal Findings: Standard microbiological culture and phenotypic identification of bacteria in sputa from CF patients have been compared to molecular methods by the use of 16S rDNA amplification, cloning and sequencing. Twenty-five sputa from CF patients were cultured that yield 33 isolates (13 species) known to be pathogens during CF. For molecular cloning, 760 clones were sequenced (7.263.9 species/sputum), and 53 different bacterial species were identified including 16 species of anaerobes (30%). Discrepancies between culture and molecular data were numerous and demonstrate that accurate identification remains challenging. New or emerging bacteria not or rarely reported in CF patients were detected including Dolosigranulum pigrum, Dialister pneumosintes, and Inquilinus limosus. Conclusions/Significance: Our results demonstrate the complex microbial community in sputa from CF patients, especially anaerobic bacteria that are probably an underestimated cause of CF lung pathology. Metagenomic analysis is urgentl
The nuanced nature of work quality : evidence from rural Newfoundland and Ireland
This article explores the relationship between job and work quality and argues that while it is important to examine job quality, to understand workers’ experiences fully, the focus should be on the broader concept of work quality, which places the job against its wider socio-economic context. Based on the experiences of 88 rural workers gathered via interviews in Newfoundland and Ireland, it appears that the same or similar jobs can be regarded very differently depending upon the context in which they are embedded, as people at different locations and/or stages of life have an individual set of aspirations, expectations and life experiences. The study found that the factors that affect work quality are moulded by broader aspects of life – family, friends, community, lifestyle and past experiences – that shape an individual
Urban semiosis: Creative industries and the clash of systems
© The Author(s) 2014. This article has two aims. The first is to make the case that the ‘universe of the mind’ imagined by Yuri Lotman may be considered as a foundational model for cultural evolution (population-wide, dynamic, autopoietic, self-organising adaptation to changing environments). The second aim is to take forward a model of culture derived from Lotman’s work – a model I call ‘the clash of systems’ – in order to apply it to creative industries research. Such a move has the salutary effect of putting the ‘universe of the mind’ literally in its place. That place, now, predominantly, is in the city. Thus, the article uses Lotman’s model of the semiosphere to link different complex systems, principally the semiosphere with that of the city, in order to explore the productive potential of encounters – clashes – between different systems. Applying these insights to the field of creative industries research, the article proposes that creative culture in the globalised, urban and web-connected era can be characterised as ‘urban semiosis’
Tissue- and hormone- dependent progesterone receptor distribution in the rat uterus
BACKGROUND: Estradiol (E2) and progesterone (P) are well known regulators of progesterone receptor (PR) expression in the rat uterus. However, it is not known which receptor subtypes are involved. Little knowledge exist about possible differences in PR regulation through ERalpha or ERbeta, and whether the PR subtypes are differently regulated depending on ER type bound. Thus, in the present study PR immunostaining has been examined in uteri of ovariectomized (ovx) rats after different treatments of estrogen and P, in comparison with that in immature, cycling, and pregnant animals. METHODS: The uteri were collected from 1) ovx rats treated with E2 and/or P; 2) immature rats, intact cycling rats and animals pregnant day 8 and 18; 3) ovx rats treated with E2 or an estrogen receptor (ER)alpha agonist or an ERbeta agonist. Two antibodies were used, one detecting PRA+B and another one specific for PRB. Real-time PCR was used to determine mRNA levels for PRAB and PRB in experiment 3. RESULTS: In stroma and myometrium faint staining was detected in ovx controls (OvxC), whereas E2 treatment resulted in strong staining. In contrast to this, in luminal epithelium (LE) the staining was strong in the OvxC group, whereas E2 treatment during the last 24 hrs before sacrifice caused a decrease. Similar to OvxC the LE of the immature animals was strongly stained. In the pregnant rats LE was negative, well in agreement with the results seen after E2 treatment. In the pregnant animals the stroma and decidua was strongly stained for PRAB, but only faint for PRB, indicating that PRA is the most expressed isoform in this state. The increase in stromal and myometrial immunostaining after E2 treatment was also found after treatment with the ERalpha agonist PPT. The ERbeta agonist DPN caused a decrease of the PR mRNA levels, which was also found for PRAB and PRB immunostaining in the GE. CONCLUSION: Stromal and myometrial PRAB levels are increased via ERalpha, as shown by treatment with E2 and the ERalpha agonist PPT, while the levels in LE are decreased. The uterine stroma of pregnant rats strongly expressed PRAB, but very little PRB, which is different to E2 treated ovx animals where both PRAB and PRB are strongly expressed. The ERbeta agonist DPN decreased the mRNA levels of PRAB and PRB, as well as the PRAB protein level in GE. These results suggest that ERbeta signals mainly down-regulate PR levels in the epithelial cells. ERalpha, on the other hand, up-regulates PR levels in the stroma and myometrium while it decreased them in LE. Thus, the effects from E2 and PPT on the mRNA levels, as determined by PCR, could be annihilated since they are increased and decreased depending on cell type. The distribution and amount of PR isoforms strongly depend on the hormonal milieu and cell type within the rat uterus
Life Cycle-Dependent Cytoskeletal Modifications in Plasmodium falciparum Infected Erythrocytes
10.1371/journal.pone.0061170PLoS ONE84
Relationship between soy and isoflavone intake and periodontal disease: The Freshmen in Dietetic Courses Study II
<p>Abstract</p> <p>Background</p> <p>Much research has shown that soy products inhibited various diseases. However, no published studies have examined the effects of consumption of soy and isoflavones on periodontal disease. The aim of this study was to investigate whether soy and isoflavone intake is associated with the prevalence of periodontal disease.</p> <p>Methods</p> <p>The subjects were 3956 Japanese female students, aged 18 to 22 years, who were taking a dietetic course. Periodontal disease was defined as present when a subject reported diagnosis of the disorder by a dentist. Information on dietary factors was collected using a validated diet history questionnaire. Logistic regression analysis was used to estimate the odds ratios and their confidence intervals of periodontal disease. Adjustment was made for cigarette smoking, toothbrushing frequency, region of residence, and body mass index.</p> <p>Results</p> <p>The prevalence of periodontal disease was 8.0%. Intake of total soy product and tofu was independently associated with a decreased prevalence of periodontal disease; multivariate odds ratios in comparison of the highest with the lowest quintile were 0.68 and 0.68, respectively (95% confidence intervals = 0.47–0.97 and 0.47–0.98, <it>P </it>for trend = 0.01 and 0.004, respectively). A significant inverse dose-response relationship between the intake of isoflavones and the prevalence of periodontal disease was observed, although the difference in the adjusted odds ratio between the extreme quintiles was of borderline significance (<it>P </it>for trend = 0.04). There were no measurable dose-response relationships between consumption of tofu products, fermented soybeans, boiled soybeans, miso, or miso soup and the prevalence of periodontal disease.</p> <p>Conclusion</p> <p>Our findings suggest that soy and isoflavone intake may decrease the likelihood of periodontal disease. Further investigations with objective measures for periodontal disease are needed to confirm our findings.</p
Acute graft versus host disease
Acute graft-versus-host disease (GVHD) occurs after allogeneic hematopoietic stem cell transplant and is a reaction of donor immune cells against host tissues. Activated donor T cells damage host epithelial cells after an inflammatory cascade that begins with the preparative regimen. About 35%–50% of hematopoietic stem cell transplant (HSCT) recipients will develop acute GVHD. The exact risk is dependent on the stem cell source, age of the patient, conditioning, and GVHD prophylaxis used. Given the number of transplants performed, we can expect about 5500 patients/year to develop acute GVHD. Patients can have involvement of three organs: skin (rash/dermatitis), liver (hepatitis/jaundice), and gastrointestinal tract (abdominal pain/diarrhea). One or more organs may be involved. GVHD is a clinical diagnosis that may be supported with appropriate biopsies. The reason to pursue a tissue biopsy is to help differentiate from other diagnoses which may mimic GVHD, such as viral infection (hepatitis, colitis) or drug reaction (causing skin rash). Acute GVHD is staged and graded (grade 0-IV) by the number and extent of organ involvement. Patients with grade III/IV acute GVHD tend to have a poor outcome. Generally the patient is treated by optimizing their immunosuppression and adding methylprednisolone. About 50% of patients will have a solid response to methylprednisolone. If patients progress after 3 days or are not improved after 7 days, they will get salvage (second-line) immunosuppressive therapy for which there is currently no standard-of-care. Well-organized clinical trials are imperative to better define second-line therapies for this disease. Additional management issues are attention to wound infections in skin GVHD and fluid/nutrition management in gastrointestinal GVHD. About 50% of patients with acute GVHD will eventually have manifestations of chronic GVHD
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