270 research outputs found

    RASSF1A–LATS1 signalling stabilizes replication forks by restricting CDK2-mediated phosphorylation of BRCA2

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    Genomic instability is a key hallmark of cancer leading to tumour heterogeneity and therapeutic resistance. ​BRCA2 has a fundamental role in error-free DNA repair but also sustains genome integrity by promoting ​RAD51 nucleofilament formation at stalled replication forks. ​CDK2 phosphorylates ​BRCA2 (pS3291-​BRCA2) to limit stabilizing contacts with polymerized ​RAD51; however, how replication stress modulates ​CDK2 activity and whether loss of pS3291-​BRCA2 regulation results in genomic instability of tumours are not known. Here we demonstrate that the Hippo pathway kinase ​LATS1 interacts with ​CDK2 in response to genotoxic stress to constrain pS3291-​BRCA2 and support ​RAD51 nucleofilaments, thereby maintaining genomic fidelity during replication stalling. We also show that ​LATS1 forms part of an ​ATR-mediated response to replication stress that requires the tumour suppressor ​RASSF1A. Importantly, perturbation of the ​ATR–​RASSF1A–​LATS1 signalling axis leads to genomic defects associated with loss of ​BRCA2 function and contributes to genomic instability and ‘BRCA-ness’ in lung cancers

    Convergence of Cells from the Progenitor Fraction of Adult Olfactory Bulb Tissue to Remyelinating Glia in Demyelinating Spinal Cord Lesions

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    Progenitor cells isolated from adult brain tissue are important tools for experimental studies of remyelination. Cells harvested from neurogenic regions in the adult brain such as the subependymal zone have demonstrated remyelination potential. Multipotent cells from the progenitor fraction have been isolated from the adult olfactory bulb (OB) but their potential to remyelinate has not been studied. cell bodies adjacent to and surrounding peripheral-type myelin rings.We report that neural cells from the progenitor fraction of the adult rat OB grown in monolayers can be expanded for several passages in culture and that upon transplantation into a demyelinated spinal cord lesion provide extensive remyelination without ectopic neuronal differentiation

    Effects of a comprehensive cardiac rehabilitation program on quality of life and exercise tolerance in women: A retrospective analysis

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    BACKGROUND: Currently, there are a lack of investigations that have examined the effect of participating in a comprehensive cardiac rehabilitation program on quality of life and physiological measures in women of different ages. The purpose of this investigation was to examine the effect of participating in a comprehensive cardiac rehabilitation program on quality of life, exercise tolerance, blood pressure and lipids in women between 33 and 82 years of age. METHODS: The 126 women participated in a 14-week cardiac rehabilitation program that consisted of 7 weeks of formal supervised exercise training and 7 weeks of unsupervised exercise and lifestyle modification. Physiologic and quality of life outcome measures obtained at the outset and after 14 weeks included: 1) exercise treadmill time; 2) resting and peak systolic and diastolic blood pressure; 3) total cholesterol, low-density lipoprotein cholesterol, high density lipoprotein cholesterol and Triglycerides; 4) Cardiac Quality of Life Index questionnaire. RESULTS: Significant improvements were found in the following quality of life measures after participating in the cardiac rehabilitation program: physical well being, psychosocial, worry, nutrition and symptoms. No significant differences were seen for any QOL variable between the different age groups. Significant improvements were seen in exercise tolerance (+21%) and high density lipoprotein (+5%). CONCLUSION: Cardiac rehabilitation may play an important role in improving quality of life, exercise tolerance and high density lipoprotein cholesterol levels in younger and older women with underlying cardiovascular disease

    A Third Measure-Metastable State in the Dynamics of Spontaneous Shape Change in Healthy Human's White Cells

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    Human polymorphonuclear leucocytes, PMN, are highly motile cells with average 12-15 µm diameters and prominent, loboid nuclei. They are produced in the bone marrow, are essential for host defense, and are the most populous of white blood cell types. PMN also participate in acute and chronic inflammatory processes, in the regulation of the immune response, in angiogenesis, and interact with tumors. To accommodate these varied functions, their behavior is adaptive, but still definable in terms of a set of behavioral states. PMN morphodynamics have generally involved a non-equilibrium stationary, spheroid Idling state that transitions to an activated, ellipsoid translocating state in response to chemical signals. These two behavioral shape-states, spheroid and ellipsoid, are generally recognized as making up the vocabulary of a healthy PMN. A third, “random” state has occasionally been reported as associated with disease states. I have observed this third, Treadmilling state, in PMN from healthy subjects, the cells demonstrating metastable dynamical behaviors known to anticipate phase transitions in mathematical, physical, and biological systems. For this study, human PMN were microscopically imaged and analyzed as single living cells. I used a microscope with a novel high aperture, cardioid annular condenser with better than 100 nanometer resolution of simultaneous, mixed dark field and intrinsic fluorescent images to record shape changes in 189 living PMNs. Relative radial roundness, R(t), served as a computable order parameter. Comparison of R(t) series of 10 cells in the Idling and 10 in the Treadmilling state reveals the robustness of the “random” appearing Treadmilling state, and the emergence of behaviors observed in the neighborhood of global state transitions, including increased correlation length and variance (divergence), sudden jumps, mixed phases, bimodality, power spectral scaling and temporal slowing. Wavelet transformation of an R(t) series of an Idling to Treadmilling state change, demonstrated behaviors concomitant with the observed transition

    Barriers to colorectal cancer screening in community health centers: A qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Colorectal cancer screening rates are low among disadvantaged patients; few studies have explored barriers to screening in community health centers. The purpose of this study was to describe barriers to/facilitators of colorectal cancer screening among diverse patients served by community health centers.</p> <p>Methods</p> <p>We identified twenty-three outpatients who were eligible for colorectal cancer screening and their 10 primary care physicians. Using in-depth semi-structured interviews, we asked patients to describe factors influencing their screening decisions. For each unscreened patient, we asked his or her physician to describe barriers to screening. We conducted patient interviews in English (n = 8), Spanish (n = 2), Portuguese (n = 5), Portuguese Creole (n = 1), and Haitian Creole (n = 7). We audiotaped and transcribed the interviews, and then identified major themes in the interviews.</p> <p>Results</p> <p>Four themes emerged: 1) Unscreened patients cited lack of trust in doctors as a barrier to screening whereas few physicians identified this barrier; 2) Unscreened patients identified lack of symptoms as the reason they had not been screened; 3) A doctor's recommendation, or lack thereof, significantly influenced patients' decisions to be screened; 4) Patients, but not their physicians, cited fatalistic views about cancer as a barrier. Conversely, physicians identified competing priorities, such as psychosocial stressors or comorbid medical illness, as barriers to screening. In this culturally diverse group of patients seen at community health centers, similar barriers to screening were reported by patients of different backgrounds, but physicians perceived other factors as more important.</p> <p>Conclusion</p> <p>Further study of these barriers is warranted.</p

    Lucy's Flat Feet: The Relationship between the Ankle and Rearfoot Arching in Early Hominins

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    BACKGROUND. In the Plio-Pleistocene, the hominin foot evolved from a grasping appendage to a stiff, propulsive lever. Central to this transition was the development of the longitudinal arch, a structure that helps store elastic energy and stiffen the foot during bipedal locomotion. Direct evidence for arch evolution, however, has been somewhat elusive given the failure of soft-tissue to fossilize. Paleoanthropologists have relied on footprints and bony correlates of arch development, though little consensus has emerged as to when the arch evolved. METHODOLOGY/PRINCIPAL FINDINGS. Here, we present evidence from radiographs of modern humans (n=261) that the set of the distal tibia in the sagittal plane, henceforth referred to as the tibial arch angle, is related to rearfoot arching. Non-human primates have a posteriorly directed tibial arch angle, while most humans have an anteriorly directed tibial arch angle. Those humans with a posteriorly directed tibial arch angle (8%) have significantly lower talocalcaneal and talar declination angles, both measures of an asymptomatic flatfoot. Application of these results to the hominin fossil record reveals that a well developed rearfoot arch had evolved in Australopithecus afarensis. However, as in humans today, Australopithecus populations exhibited individual variation in foot morphology and arch development, and "Lucy" (A.L. 288-1), a 3.18 Myr-old female Australopithecus, likely possessed asymptomatic flat feet. Additional distal tibiae from the Plio-Pleistocene show variation in tibial arch angles, including two early Homo tibiae that also have slightly posteriorly directed tibial arch angles. CONCLUSIONS/SIGNIFICANCE. This study finds that the rearfoot arch was present in the genus Australopithecus. However, the female Australopithecus afarensis "Lucy" has an ankle morphology consistent with non-pathological flat-footedness. This study suggests that, as in humans today, there was variation in arch development in Plio-Pleistocene hominins.Leakey Foundatio
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