1,077 research outputs found
Commentary : missing targets on drugs-related deaths, and a Scottish paradox
The 10-year drug strategy for England and Wales was published in February 2008. It dropped drugs-related deaths (DRDs) as a key performance indicator. Scotland retained a necessary strong focus on DRDs. Scotland's DRDs numbered 1006 in 2000–02 and 1009 in 2003–05. The previous Scottish administration's claim that its number of current injectors had decreased substantially between 2000 and 2003 implied, paradoxically, that their DRD rate would have to have increased. Worse was to come: Scotland's DRDs had increased to 876 in 2006 + 2007. We analyse UK's DRDs by sex and age-group to reveal temporal trends (2000–02 versus 2003–05 versus 2006 + 2007) with different public health and epidemiological implications. We also address the above Scottish paradox and assess, by age-group, how consistent Scotland's 876 DRDs in 2006 + 2007 are with Scottish injectors’ DRD rate in 2003–05 of around 1 per 100 injector-years. Public health success in the UK in reducing DRDs at younger ages should not be overshadowed by the late consequence in terms of older-age DRDs of UK's injector epidemics; in the early 1980s in Scotland, and late 1980s in England and Wales. Targets for reducing DRDs should pay heed to UK's injector epidemics
Cardiovascular Functional Changes in Chronic Kidney Disease:Integrative Physiology, Pathophysiology and Applications of Cardiopulmonary Exercise Testing
The development of cardiovascular disease during renal impairment involves striking multi-tiered, multi-dimensional complex alterations encompassing the entire oxygen transport system. Complex interactions between target organ systems involving alterations of the heart, vascular, musculoskeletal and respiratory systems occur in Chronic Kidney Disease (CKD) and collectively contribute to impairment of cardiovascular function. These systemic changes have challenged our diagnostic and therapeutic efforts, particularly given that imaging cardiac structure at rest, rather than ascertainment under the stress of exercise, may not accurately reflect the risk of premature death in CKD. The multi-systemic nature of cardiovascular disease in CKD patients provides strong rationale for an integrated approach to the assessment of cardiovascular alterations in this population. State-of-the-art cardiopulmonary exercise testing (CPET) is a powerful, dynamic technology that enables the global assessment of cardiovascular functional alterations and reflects the integrative exercise response and complex machinery that form the oxygen transport system. CPET provides a wealth of data from a single assessment with mechanistic, physiological and prognostic utility. It is an underutilized technology in the care of patients with kidney disease with the potential to help advance the field of cardio-nephrology. This article reviews the integrative physiology and pathophysiology of cardio-renal impairment, critical new insights derived from CPET technology, and contemporary evidence for potential applications of CPET technology in patients with kidney disease
Identifying novel hypoxia-associated markers of chemoresistance in ovarian cancer
BACKGROUND
Ovarian cancer is associated with poor long-term survival due to late diagnosis and development of chemoresistance. Tumour hypoxia is associated with many features of tumour aggressiveness including increased cellular proliferation, inhibition of apoptosis, increased invasion and metastasis, and chemoresistance, mostly mediated through hypoxia-inducible factor (HIF)-1α. While HIF-1α has been associated with platinum resistance in a variety of cancers, including ovarian, relatively little is known about the importance of the duration of hypoxia. Similarly, the gene pathways activated in ovarian cancer which cause chemoresistance as a result of hypoxia are poorly understood. This study aimed to firstly investigate the effect of hypoxia duration on resistance to cisplatin in an ovarian cancer chemoresistance cell line model and to identify genes whose expression was associated with hypoxia-induced chemoresistance.
METHODS
Cisplatin-sensitive (A2780) and cisplatin-resistant (A2780cis) ovarian cancer cell lines were exposed to various combinations of hypoxia and/or chemotherapeutic drugs as part of a 'hypoxia matrix' designed to cover clinically relevant scenarios in terms of tumour hypoxia. Response to cisplatin was measured by the MTT assay. RNA was extracted from cells treated as part of the hypoxia matrix and interrogated on Affymetrix Human Gene ST 1.0 arrays. Differential gene expression analysis was performed for cells exposed to hypoxia and/or cisplatin. From this, four potential markers of chemoresistance were selected for evaluation in a cohort of ovarian tumour samples by RT-PCR.
RESULTS
Hypoxia increased resistance to cisplatin in A2780 and A2780cis cells. A plethora of genes were differentially expressed in cells exposed to hypoxia and cisplatin which could be associated with chemoresistance. In ovarian tumour samples, we found trends for upregulation of ANGPTL4 in partial responders and down-regulation in non-responders compared with responders to chemotherapy; down-regulation of HER3 in partial and non-responders compared to responders; and down-regulation of HIF-1α in non-responders compared with responders.
CONCLUSION
This study has further characterized the relationship between hypoxia and chemoresistance in an ovarian cancer model. We have also identified many potential biomarkers of hypoxia and platinum resistance and provided an initial validation of a subset of these markers in ovarian cancer tissues
A 200 Year Sulfate Record from Sixteen Antarctic Ice Cores and Associations With Southern Ocean Sea-Ice Extent
Chemistry data from 16, 50-115 m deep, sub-annually dated ice cores are used to investigate spatial and temporal concentration variability of sea-salt (ss) SO42- and excess (xs) SO42- over West Antarctica and the South Pole for the last 200 years. Low-elevation ice-core sites in western West Antarctica contain higher concentrations Of SO42- as a result of cyclogenesis over the Ross Ice Shelf and proximity to the Ross Sea Polynya. Linear correlation analysis of 15 West Antarctic ice-core SO42- time series demonstrates that at several sites concentrations Of ssSO(4)(2-) are higher when sea-ice (SIE) extent is greater, and the inverse for XSS04. Concentrations Of XSS04 from the South Pole site (East Antarctica) are associated with SIE from the Weddell region, and West Antarctic XSSO42- concentrations are associated with SIE from the Bellingshausen-Amundsen-Ross region. The only notable rise of the last 200 years in xsSO(4)(2-), around 1940, is not related to SIE fluctuations and is most likely a result of increased xsSO(4)(2-) production in the mid-low latitudes and/or an increase in transport efficiency from the mid-low latitudes to central West Antarctica. These high-resolution records show that the source types and source areas Of ssSO(4)(2-) and xsSO(4)(2-) delivered to eastern and western West Antarctica and the South Pole differ from site to site but can best be resolved using records from spatial ice-core arrays such as the International Trans-Antarctic Scientific Expedition (ITASE)
Cumulative mutagenesis of the basic residues in the 201-218 region of insulin-like growth factor (IGF)-binding protein-5 results in progressive loss of both IGF-I binding and inhibition of IGF-I biological action
We have reported previously that mutation of two conserved nonbasic amino acids (G203 and Q209) within the highly basic 201–218 region in the C-terminal domain of IGF-binding protein-5 (IGFBP-5) decreases binding to IGFs. This study reveals that cumulative mutagenesis of the 10 basic residues in this region, to create the C-Term series of mutants, ultimately results in a 15-fold decrease in the affinity for IGF-I and a major loss in heparin binding. We examined the ability of mutants to inhibit IGF-mediated survival of MCF-7 cells and were able to demonstrate that this depended not only upon the affinity for IGF-I, but also the kinetics of this interaction, because IGFBP-5 mutants with similar affinity constants (KD) values, but with different association (Ka) and dissociation (Kd) rate values, had markedly different inhibitory properties. In contrast, the affinity for IGF-I provided no predictive value in terms of the ability of these mutants to enhance IGF action when bound to the substratum. Instead, these C-Term mutants appeared to enhance the actions of IGF-I by a combination of increased dissociation of IGF-IGFBP complexes from the substratum, together with dissociation of IGF-I from IGFBP-5 bound to the substratum. These effects of the IGFBPs were dependent upon binding to IGF-I, because a non-IGF binding mutant (N-Term) was unable to inhibit or enhance the actions of IGF-I. These results emphasize the importance of the kinetics of association/dissociation in determining the enhancing or inhibiting effects of IGFBP-5 and demonstrate the ability to generate an IGFBP-5 mutant with exclusively IGF-enhancing activity
Per- and Polyfluoroalkyl Substances and Bone Mineral Density in Mid-childhood
Background:
• Identifying factors that impair bone accrual during childhood is a critical step toward osteoporosis prevention.
• One potential risk factor not well characterized in childhood is the role of chemicals in the environment.
• Perfluoroalkyl substances (PFASs) are synthetic additives used to make clothing, furniture, and cookware stain repellant and are detectable in almost all US adults.
• PFASs act as PPAR-γ agonists,2 androgen receptor antagonists, and directly intercalate into bone, raising the possibility that they may lead to low bone accrual.
• While two population-based studies in adults have shown associations between PFASs and low areal bone mineral density (aBMD),5,6 the extent to which PFASs may affect aBMD in children is unknown
Development of a brief and effective temporomandibular disorder pain screening questionnaire: Reliability and validity
Background—Available screening instruments for identifying temporomandibular disorders
(TMDs) exhibit methodological or logistic limitations. The authors conducted a study to develop
and assess the validity of a self-report instrument in screening patients for pain-related TMDs.
Methods—By using psychometric methods for item selection, the authors developed short
(three-item) and long (six-item) versions of the questionnaire and evaluated them for validity
among 504 participants.
Results—Internal reliability was excellent, with coefficient α values of 0.87 and 0.93 for the
short and long versions, respectively. When the authors dichotomized instrument scores at optimal
thresholds, both versions had a sensitivity of 99 percent and a specificity of 97 percent for correct
classification of the presence or absence of TMD. The specificity was at least 95 percent in the
correct identification of people with nonpainful TMJ disorders or headahce without TMD pain.
Conclusions—With use of appropriate psychometric methodology, the selected items exhibited
excellent content validity. The excellent levels of reliability, sensitivity and specificity
demonstrate the validity and usefulness of this instrument.
Clinical Implications—Using this instrument will allow clinicians to identify more readily—
and cost-effectively—most patients with painful TMD conditions for whom early and reliable
identification would have a significant effect on diagnosis, treatment and prognosis
Exploring the self-assembly and energy transfer of dynamic supramolecular iridium-porphyrin systems
EZ-C acknowledges the University of St Andrews for financial support. IDWS acknowledges support from EPSRC (EP/J009016) and the European Research Council (grant 321305). IDWS also acknowledges support from a Royal Society Wolfson research merit award. DJ acknowledges the European Research Council (grant: 278845) and the RFI Lumomat for financial support.We present the first examples of dynamic supramolecular systems composed of cyclometalated Ir(III) complexes of the form of [Ir(C^N)2(N^N)]PF6 (where C^N is mesppy = 2-phenyl-4-mesitylpyridinato and dFmesppy = 2-(4,6-difluorophenyl)-4-mesitylpyridinato and N^N is 4,4':2',2'':4'',4'''-quaterpyridine, qpy) and zinc tetraphenylporphyrin (ZnTPP), assembled through non-covalent interactions between the distal pyridine moieties of the qpy ligand located on the iridium complex and the zinc of the ZnTPP. The assemblies have been comprehensively characterized by a series of analytical techniques (1H NMR titration experiments, 2D COSY and HETCOR NMR spectra and low temperature 1H NMR spectroscopy) and the crystal structures have been elucidated by X-ray diffraction. The optoelectronic properties of the assemblies and the electronic interaction between the iridium and porphyrin chromophoric units have been explored with detailed photophysical measurements, supported by time-dependent density functional theory (TD-DFT) calculations.PostprintPeer reviewe
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