Meson distribution amplitudes in holographic models

We study the wave functions of light and heavy mesons in both hard-wall (HW) and soft-wall (SW) holographic models which use AdS/CFT correspondence. In the case of massless constituents, the asymptotic behaviors of the electromagnetic form factor, the distribution amplitudes, and the decay constants for the two models are the same, if the relation between the dilaton scale parameter and the size of meson is an inverse proportion. On the other hand, by introducing a quark mass dependence in the wave function, the differences of the distribution amplitudes between the two models are obvious. In addition, for the SW model, the dependences of the decay constants of meson on the dilaton scale parameter $\kappa$ differ; especially f_{Qq}\sim \kappa^3/m_Q^2 is consistent with the prediction of the heavy quark effective theory if \kappa\sim m_Q^{1/2}. Thus the parameters of the two models are fit by the decay constants of the distinct mesons; the distribution amplitudes and the \xi-moments are calculated and compared.Comment: 30 pages, 11 figures, 2 tables, minor modifications and one short paragraph added, some references added and removed, accepted for publication in PR

Decision and Discovery in Defining “Disease”

This version (May 17, 2005) was published in its final form as: Schwartz PH. Decision and discovery in defining 'disease'. In: Kincaid H, McKitrick J, editors. Establishing medical reality: essays in the metaphysics and epistemology of biomedical science. Dordrecht: Springer; 2007. p. 47-63. http://dx.doi.org/10.1007/1-4020-5216-2_5The debate over how to analyze the concept of disease has often centered on the question of whether to include a reference to values, in particular the ‘disvalue’of diseases, or whether to avoid such notions. ‘Normativists,’such as King ([1954], 1981) and Culver and Gert (1982) emphasize the undesirability of diseases, while ‘Naturalists,’ most prominently Christopher Boorse (1977, 1987, 1997), instead require just the presence of biological dysfunction. The debate between normativism and naturalism often deteriorates into stalemate, with each side able to point out significant problems with the other. It starts to look as if neither approach can work. In this paper, I argue that the standoff stems from deeply questionable assumptions that have been used to formulate the opposing positions and guide the debate. In the end, I propose an alternative set of guidelines that offer a more constructive way to devise and compare theories

Pulsed Feedback Defers Cellular Differentiation

Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable “polyphasic” positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a “timer” that operates over timescales much longer than a cell cycle

Predictors of progression free survival, overall survival and early cessation of chemotherapy in women with potentially platinum sensitive (PPS) recurrent ovarian cancer (ROC) starting third or subsequent line(> 3) chemotherapy – the GCIG Symptom Benefit Study (SBS)

Background: Potentially platinum sensitive recurrent ovarian cancer (PPS ROC) is defined by a platinum-free interval of >6 months, and usually treated with platinum-based chemotherapy with variable response and benefit in women who have had 3 or more lines of chemotherapy(≥3). We identified baseline characteristics (health-related quality of life[HRQL] and clinicopathological factors), associated with PFS, OS and early progression (within 8 weeks). The goal is to improve patient selection for chemotherapy based on a nomogram predicting PFS. Methods: HRQL was assessed with EORTC QLQ-C30/QLQ-OV28. Associations with PFS and OS were assessed with Cox proportional hazards regression. Variables significant in univariable analysis were included in multivariable analyses using backward elimination to select those significant. Associations with stopping chemotherapy early were assessed with logistic regression. Results: 378 women were enrolled, with median(m)OS and PFS of 16.6 months and 5.3 months, respectively. The majority had ECOGPS 0–1. Chemotherapy was stopped early in 45/378 participants (12%); with mOS 3.4 months (95% CI: 1.7–7.2). Physical function(PF), role function(RF), cognitive function(CF), social function(SF), Global Health Status(GHS) and abdominal/GI symptoms(AGIS) were significant univariable predictors of PFS(p < 0.030). SF remained significant after adjusting for clinicopathological factors; p = 0.03. PF, RF, CF, SF, GHS and AGIS were significant univariable predictors of OS (p < 0.007); PF, RF, SF and GHS remained significant predictors of OS in multivariable models; p < 0.007. Poor baseline PF and GHS were significant univariable predictors of stopping chemotherapy early (p < 0.007) but neither remained significant after adjusting for clinicopathological factors. Conclusion: Baseline HRQL is simple to measure, is predictive of PFS and OS and when used in conjunction with clinicopathological prognostic factors, can assist with clinical decision making and treatment recommendations for women with PPSROC≥3

Health and social care professionals’ experiences of providing end of life care during the COVID-19 pandemic: A qualitative study

Background: Health and social care professionals’ ability to address the needs of patients and their relatives at end of life is likely to have been impacted by the COVID-19 pandemic. Aim: To explore health and social care professionals’ experiences of providing end of life care during the COVID-19 pandemic to help inform current/future clinical practice and policy. Design: A qualitative interview study. Data were analysed using thematic analysis. Setting/participants: Sixteen health and social care professionals working across a range of clinical settings in supporting dying patients during the first wave (March–June 2020) of the COVID-19 pandemic in the United Kingdom. Results: Participants reported emotional and practical challenges to providing end of life care during the pandemic, including increases in patient numbers, reduced staffing levels and relying on virtual platforms for sensitive, emotive conversations with relatives. Participants were central to promoting connections between patients and their families at end of life and creating opportunities for a final contact before the death. However, the provision of support varied as a consequence of the pressures of the pandemic. Results are discussed under two themes: (1) challenges and facilitators to providing end of life care, and (2) support needs of relatives when a family member was dying during the COVID-19 pandemic. Conclusion: There is a need for flexible visiting arrangements at end of life during a pandemic. A systems-level approach is necessary to promote the wellbeing of health and social care professionals providing end of life care during and after a pandemic

Therapeutic monoclonal antibodies for Ebola virus infection derived from vaccinated humans

We describe therapeutic monoclonal antibodies isolated from human volunteers vaccinated with recombinant adenovirus expressing Ebola virus glycoprotein (EBOV GP) and boosted with modified vaccinia virus Ankara. Among 82 antibodies isolated from peripheral blood B cells, almost half neutralized GP pseudotyped influenza virus. The antibody response was diverse in gene usage and epitope recognition. Although close to germline in sequence, neutralizing antibodies with binding affinities in the nano- to pico-molar range, similar to “affinity matured” antibodies from convalescent donors, were found. They recognized the mucin-like domain, glycan cap, receptor binding region, and the base of the glycoprotein. A cross-reactive cocktail of four antibodies, targeting the latter three non-overlapping epitopes, given on day 3 of EBOV infection, completely protected guinea pigs. This study highlights the value of experimental vaccine trials as a rich source of therapeutic human monoclonal antibodies

Are public health measures and individualised care compatible in the face of a pandemic? A national observational study of bereaved relatives’ experiences during the COVID-19 pandemic

Background: COVID-19 public health restrictions have affected end-of-life care experiences for dying patients and their families. Aim: To explore bereaved relatives’ experiences of quality of care and family support provided during the last days of life; to identify the impact of factors associated with perceived support. Design: A national, observational, open online survey was developed and disseminated via social media, public fora and professional networks (June–September 2020). Validated instruments and purposively designed questions assessed experiences. Analysis used descriptive statistics, logistic regression and thematic analysis of free-text responses. Participants: Individuals (⩾18 years) who had experienced the death of a relative/friend (all care settings) within the United Kingdome during the COVID-19 pandemic. Results: Respondents (n = 278, mean 53.4 years) tended to be female (n = 216, 78%); over half were ‘son/daughter’ (174, 62.6%) to the deceased. Deceased individuals (mean 81.6 years) most frequently died in their ‘usual place of care’ (n = 192, 69.3%). Analysis established five conceptual themes affecting individualised care: (1) public health restrictions compounding the distress of ‘not knowing’; (2) disparate views about support from doctors and nurses; (3) challenges in communication and level of preparedness for the death; (4) delivery of compassionate care; (5) emotional needs and potential impact on grief. Male respondents (OR 2.9, p = 0.03) and those able to visit (OR 2.2, p = 0.04) were independently associated with good perceptions of family support. Conclusion: Despite public health restrictions, individualised care can be enabled by proactive, informative communication; recognising dying in a timely manner and facilitating the ability to be present before death

Cyclin D1, cyclin E, and p21 have no apparent prognostic value in anal carcinomas treated by radiotherapy with or without chemotherapy

The purpose of this study was to assess the potential prognostic and/or predictive value of the expression of cyclin D1, cyclin E, and p21 protein in a series of 98 anal carcinomas (T1-4, N0-3) treated by radiotherapy with (51) or without (47) chemotherapy in one institution. Correlation with Mib1 index and p53 expression was also investigated. Median follow-up for surviving patients was 124 months (range: 30-266). Immunohistochemical staining was performed on pretreatment biopsies, applying a standard ABC technique for cyclin D1 (clone DSC6, DAKO, 1 : 300), cyclin E (clone 13A3, Novocastra, 1 : 100), p21(WAF/CIP1) (clone SX118, DAKO, 1 : 50), p53 (clone DO7, DAKO, 1 : 200), and Mib1 (Ki-67, Dianova, 1 : 20). Tumours were classified into low- or high-expression groups according to the expression level of the protein considered. High expression was found in 51% of tumours for cyclin E, in 33.7% for cyclin D1, and in 65% for p21. None of those factors were significantly associated with clinical variables such as advanced T or N categories. In a monovariate analysis, advanced T and N categories and longer overall treatment time were the only variables that correlated significantly with low rate of local control (LC) and disease-free survival. However, in a subgroup analysis, high p21 expression correlated with a trend for significantly higher 5-year LC (87 vs 68%, P=0.07) in the N0 patients. The results of this study suggest that the cell-cycle proteins investigated are unlikely to be clinically useful in predicting treatment response or prognosis in patients with anal carcinomas