535 research outputs found

    Induction and Amplification of Non-Newtonian Gravitational Fields

    Get PDF
    One obtains a Maxwell-like structure of gravitation by applying the weak-field approximation to the well accepted theory of general relativity or by extending Newton's laws to time-dependent systems. This splits gravity in two parts, namely a gravitoelectric and gravitomagnetic (or cogravitational) one. Due to the obtained similar structure between gravitation and electromagnetism, one can express one field by the other one using a coupling constant depending on the mass to charge ratio of the field source. Calculations of induced gravitational fields using state-of-the-art fusion plasmas reach only accelerator threshold values for laboratory testing. Possible amplification mechanisms are mentioned in the literature and need to be explored. The possibility of using the principle of equivalence in the weak field approximation to induce non-Newtonian gravitational fields and the influence of electric charge on the free fall of bodies are also investigated, leading to some additional experimental recommendations

    Four-color flow cytometric analysis of peripheral blood donor cell chimerism

    Get PDF
    Passenger leukocytes have been demonstrated to play significant roles in initiating and also regulating immune reactions after organ transplantation. Reliable techniques to detect donor leukocytes in recipients after organ transplantation are essential to analyze the role, function, and behavior of these leukocytes. In this report we describe a simple, reliable method to detect donor cells with low frequencies using peripheral blood samples. Detection of small numbers of major histocompatibility complex (MHC) mismatched cells was first studied using four-color flow cytometry in artificially created cell mixtures. By selecting the CD45+ population and simultaneous staining with several leukocyte lineage markers (CD3, CD4, CD8, CD56, and CD19), MHC-mismatched leukocytes were consistently detected in cell suspensions prepared from directly stained whole blood samples with a threshold sensitivity as low as 0.1%-0.2%. When the fresh peripheral blood mononuclear cells were separated by conventional Ficoll gradient purification, similar, but slightly lower levels of donor cells were detected. Blood samples obtained 1-5 months after liver, kidney, and intestine transplants revealed that the kind of organ allograft influenced levels and lineage pattern of the circulating donor cells. This procedure provided a simple and reliable method in determining early chimerism in transplant recipients. However, the detection of MHC-mismatched leukocytes of all lineages was much lower when frozen peripheral blood mononuclear cells were used. © American Society for Histocompatibility and Immunogenetics, 2003. Published by Elsevier Inc

    Effects of external irradiation of the neck region on intima media thickness of the common carotid artery

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Several studies have shown that common carotid intima-media thickness (IMT) is increased after radiotherapy (RT) to the head and neck. However, further studies are needed to define the exact mechanism of radiation-induced injury in large vessels, investigate the relationship between radiation dose and large vessel injury and evaluate the rate of progress of atherosclerosis in irradiated vessels.</p> <p>Objectives</p> <p>To investigate whether external irradiation to the carotid area has any effect on IMT of the common carotid artery in a group of patients who received RT vs control group matched for age, gender and race.</p> <p>Methods</p> <p>We studied 19 patients (10 male; 47.8 ± 17.4 years) during a 5-month period (January 2009-July 2009); they had completed RT with a mean of 2.9 years before (range: 1 month-6 years) The mean radiation dose to the neck in the irradiated patients was 41.2 ± 15.6 Gy (range: 25-70 Gy). Common carotid IMT was measured with echo-color Doppler. Nineteen healthy adult patients (10 male; 47.8 ± 17.6) were recruited as a control group.</p> <p>Results</p> <p>IMT was not significantly higher in patients when compared to the control group (0.59 ± 0.16 vs 0.56 ± 0.16 mm, p = 0.4). There was no significant difference between the two groups in relation to the absence (p = 0.7) or presence (p = 0.6) of vascular risk factors. Although the difference did not reach statistical significance (p = 0.1), the irradiated young patients (age ≤ 52 years) had IMT measurements higher (0.54 ± 0.08 mm) than the non-irradiated young patients (0.49 ± 0.14 mm). The mean carotid IMT increased with increasing doses of radiation to the neck (p = 0.04).</p> <p>Conclusion</p> <p>This study shows that increased IMT of the common carotid artery after RT is radiation-dose-related. Therefore it is important to monitor IMT, which can be used as an imaging biomarker for early diagnosis of cerebrovascular disease in patients who have had radiotherapy for treatment of cancer of the head and neck and who are at increased risk for accelerated atherosclerosis in carotid arteries.</p

    The Phenotypic Radiation Resistance of CD44+/CD24−or low Breast Cancer Cells Is Mediated through the Enhanced Activation of ATM Signaling

    Get PDF
    Cancer initiating cells (CIC) are stem-like cells. CIC may contribute not only to the initiation of cancer but also to cancer recurrence because of the resistance of CIC both to chemotherapy and radiation therapy. From the MCF-7 and MDA-MB231 breast cancer cell lines and primary culture of patient breast cancer cells, we isolated by flow cytometry a CIC subset of cells with the CD44+/CD24−or low phenotype. The CD44+/CD24−or low subset showed increased sphere formation and resistance to radiation compared to the non- CD44+/CD24−or low subset. The increased radiation resistance was not dependent on the result of altered non-homologous end joining (NHEJ) DNA repair activity as both NHEJ activity and expression of the various proteins involved in NHEJ were not significantly different between the CD44+/CD24−or low and non- CD44+/CD24−or low subsets. However, activation of ATM signaling was significantly increased in CD44+/CD24−or low cells compared to non- CD44+/CD24−or low cells in both from breast cancer cell lines and primary human breast cancer cells. Application of an ATM inhibitor effectively decreased the radiation resistance of CD44+/CD24−or low subset, suggesting that targeting ATM signaling may provide a new tool to eradicate stem-like CIC and abolish the radiation resistance of breast cancer

    Signs and symptoms in children with a serious infection: a qualitative study

    Get PDF
    BACKGROUND: Early diagnosis of serious infections in children is difficult in general practice, as incidence is low, patients present themselves at an early stage of the disease and diagnostic tools are limited to signs and symptoms from observation, clinical history and physical examination. Little is known which signs and symptoms are important in general practice. With this qualitative study, we aimed to identify possible new important diagnostic variables. METHODS: Semi-structured interviews with parents and physicians of children with a serious infection. We investigated all signs and symptoms that were related to or preceded the diagnosis. The analysis was done according to the grounded theory approach. Participants were recruited in general practice and at the hospital. RESULTS: 18 children who were hospitalised because of a serious infection were included. On average, parents and paediatricians were interviewed 3 days after admittance of the child to hospital, general practitioners between 5 and 8 days after the initial contact. The most prominent diagnostic signs in seriously ill children were changed behaviour, crying characteristics and the parents' opinion. Children either behaved drowsy or irritable and cried differently, either moaning or an inconsolable, loud crying. The parents found this illness different from previous illnesses, because of the seriousness or duration of the symptoms, or the occurrence of a critical incident. Classical signs, like high fever, petechiae or abnormalities at auscultation were helpful for the diagnosis when they were present, but not helpful when they were absent. CONCLUSION: behavioural signs and symptoms were very prominent in children with a serious infection. They will be further assessed for diagnostic accuracy in a subsequent, quantitative diagnostic study

    Non-Invasive In Vivo Imaging of Tumor-Associated CD133/Prominin

    Get PDF
    detection of cancer stem cells is of great importance. detection of CD133/prominin, a cancer stem cell surface marker for a variety of tumor entities. The CD133-specific monoclonal antibody AC133.1 was used for quantitative fluorescence-based optical imaging of mouse xenograft models based on isogenic pairs of CD133 positive and negative cell lines. A first set consisted of wild-type U251 glioblastoma cells, which do not express CD133, and lentivirally transduced CD133-overexpressing U251 cells. A second set made use of HCT116 colon carcinoma cells, which uniformly express CD133 at levels comparable to primary glioblastoma stem cells, and a CD133-negative HCT116 derivative. Not surprisingly, visualization and quantification of CD133 in overexpressing U251 xenografts was successful; more importantly, however, significant differences were also found in matched HCT116 xenograft pairs, despite the lower CD133 expression levels. The binding of i.v.-injected AC133.1 antibodies to CD133 positive, but not negative, tumor cells isolated from xenografts was confirmed by flow cytometry. imaging of tumor-associated CD133 is feasible and that CD133 antibody-based tumor targeting is efficient. This should facilitate developing clinically applicable cancer stem cell imaging methods and CD133 antibody-based therapeutics

    Against Modern Football: Mobilising Protest Movements in Social Media

    Get PDF
    Recent debates in sociology consider how Internet communications might catalyse leaderless, open-ended, affective social movements that broaden support and bypass traditional institutional channels to create change. We extend this work into the field of leisure and lifestyle politics with an empirical study of Internet-mediated protest movement, Stand Against Modern Football. We explain how social media facilitate communications that transcend longstanding rivalries, and engender shared affective frames that unite diverse groups against corporate logics. In examining grassroots organisation, communication and protest actions that span online and urban locations, we discover sustained interconnectedness with traditional social movements, political parties, the media and the corporate targets of protests. Finally, we suggest that Internet-based social movements establish stable forms of organisation and leadership at these networked intersections in order to advance instrumental programmes of change

    Influence of Calendar Period on the Association Between BMI and Coronary Heart Disease: A Meta-Analysis of 31 Cohorts

    Get PDF
    Objective: The association between obesity and coronary heart disease (CHD) may have changed over time, for example due to improved pharmacological treatment of CHD risk factors. This meta-analysis of 31 prospective cohort studies explores the influence of calendar period on CHD risk associated with body mass index (BMI). Design and Methods: The relative risks (RRs) of CHD for a five-BMI-unit increment and BMI categories were pooled by means of random effects models. Meta-regression analysis was used to examine the influence of calendar period (>1985 v 1985) in univariate and multivariate analyses (including mean population age as a covariate). Results: The age, sex, and smoking adjusted RR (95% confidence intervals) of CHD for a five-BMI-unit increment was 1.28(1.22:1.34). For underweight, overweight and obesity, the RRs (compared to normal weight) were 1.11(0.91:1.36), 1.31(1.22:1.41), and 1.78(1.55:2.04), respectively. The univariate analysis indicated 31% (95%CI: 56:0) lower RR of CHD associated with a five-BMI-unit increment and a 51% (95%CI: 78: 14)) lower RR associated with obesity in studies starting after 1985 (n ¼ 15 and 10, respectively) compared to studies starting in or before 1985 (n ¼ 16 and 10). However, in the multivariate analysis, only mean population age was independently associated with the RRs for a five-BMI-unit increment and obesity ( 29(95%CI: 55: 5)) and 31(95%CI: 66:3), respectively) per 10-year increment in mean age). Conclusion: This study provides no consistent evidence for a difference in the association between BMI and CHD by calendar period. The mean population age seems to be the most important factor that modifies the association between the risk of CHD and BMI, in which the RR decreases with increasing age
    corecore