543 research outputs found
Effects of creatine treatment on Jejunal phenotypes in a rat model of acidosis
We investigated the effects of creatine treatment on jejunal phenotypes in a rat model of oxidative stress induced by acidosis. In particular, the activities of some antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase), the level of lipid peroxidation, the expression of heat shock proteins (HSP70), and the expression of the major carriers of the cells (Na+/K+-ATPase, sodium-glucose Transporter 1\u2014SGLT1, and glucose transporter 2\u2014GLUT2) were measured under control and chronic acidosis conditions. Creatine did not affect the activity of antioxidant enzymes in either the control or acidosis groups, except for catalase, for which the activity was reduced in both conditions. Creatine did not change the lipid peroxidation level or HSP70 expression. Finally, creatine stimulated (Na+/K+)-ATPase expression under both control and chronic acidosis conditions. Chronic acidosis caused reductions in the expression levels of GLUT2 and SGLT1. GLUT2 reduction was abolished by creatine, while the presence of creatine did not induce any strengthening effect on the expression of SGLT1 in either the control or chronic acidosis groups. These results indicate that creatine has antioxidant properties that are realized through direct interaction of the molecule with reactive oxygen species. Moreover, the administration of creatine seems to determine a functional strengthening of the tissue, making it more resistant to acidosis
Diffusive hidden Markov model characterization of DNA looping dynamics in tethered particle experiments
In many biochemical processes, proteins bound to DNA at distant sites are
brought into close proximity by loops in the underlying DNA. For example, the
function of some gene-regulatory proteins depends on such DNA looping
interactions. We present a new technique for characterizing the kinetics of
loop formation in vitro, as observed using the tethered particle method, and
apply it to experimental data on looping induced by lambda repressor. Our
method uses a modified (diffusive) hidden Markov analysis that directly
incorporates the Brownian motion of the observed tethered bead. We compare
looping lifetimes found with our method (which we find are consistent over a
range of sampling frequencies) to those obtained via the traditional
threshold-crossing analysis (which can vary depending on how the raw data are
filtered in the time domain). Our method does not involve any time filtering
and can detect sudden changes in looping behavior. For example, we show how our
method can identify transitions between long-lived, kinetically distinct states
that would otherwise be difficult to discern
Physical characterization of colorectal cancer spheroids and evaluation of NK cell Infiltration through a flow-based analysis
To improve pathogenetic studies in cancer development and reliable preclinical testing of anti-cancer treatments, three-dimensional (3D) cultures, including spheroids, have been widely recognized as more physiologically relevant in vitro models of in vivo tumor behavior. Currently, the generation of uniformly sized spheroids is still challenging: different 3D cell culture methods produce heterogeneous populations in dimensions and morphology, that may strongly influence readouts reliability correlated to tumor growth rate or antitumor natural killer (NK) cell-mediated cytotoxicity. In this context, an increasing consensus claims the integration of microfluidic technologies within 3D cell culture, as the physical characterization of tumor spheroids is unavoidably demanded to standardize protocols and assays for in vitro testing. In this paper, we employed a flow-based method specifically conceived to measure weight, size and focused onto mass density values of tumor spheroids. These measurements are combined with confocal and digital imaging of such samples. We tested the spheroids of four colorectal cancer (CRC) cell lines that exhibit statistically relevant differences in their physical characteristics, even though starting from the same cell seeding density. These variations are seemingly cell line-dependent and associated with the number of growing cells and the degree of spheroid compaction as well, supported by different adenosine-triphosphate contents. We also showed that this technology can estimate the NK cell killing efficacy by measuring the weight loss and diameter shrinkage of tumor spheroids, alongside with the commonly used cell viability in vitro test. As the activity of NK cells relies on their infiltration rate, the in vitro sensitivity of CRC spheroids proved to be exposure time- and cell line-dependent with direct correlation to the cell viability reduction. All these functional aspects can be measured by the system and are documented by digital image analysis. In conclusion, this flow-based method potentially paves the way towards standardization of 3D cell cultures and its early adoption in cancer research to test antitumor immune response and set up new immunotherapy strategies
The energy budget in Rayleigh-Benard convection
It is shown using three series of Rayleigh number simulations of varying
aspect ratio AR and Prandtl number Pr that the normalized dissipation at the
wall, while significantly greater than 1, approaches a constant dependent upon
AR and Pr. It is also found that the peak velocity, not the mean square
velocity, obeys the experimental scaling of Ra^{0.5}. The scaling of the mean
square velocity is closer to Ra^{0.46}, which is shown to be consistent with
experimental measurements and the numerical results for the scaling of Nu and
the temperature if there are strong correlations between the velocity and
temperature.Comment: 5 pages, 3 figures, new version 13 Mar, 200
Why the ongoing occupation of Ukraine matters to ethnobiology
Ethnobiology and ethnomedicine investigate the continuously changing complex and inextricable relations among culture, nature, and health. Since the emergence of modern ethnobiology a few decades ago, its essence and mission have been the study of biocultural diversities and the centers of its inquiries have been and are local communities and their co-evolutionary interrelationships between natural environments and social systems. At the core of ethnobiologists’ work there are not only conceptualizations of and reflections on others' views about nature and the universe, but also a robust commitment to advocacy in defense of these assemblages of local ecological knowledge, practices, and beliefs (LEK). Homogenization processes and therefore erosion of LEK have occurred throughout history in different ways: from colonialism to industrialization, and from financialization to globalization; however, we cannot forget the role played by centripetal states and even dictatorships in this process, nor the associated political ideology of nationalism, which has often elicited and justified policies aimed at standardizing diversities within state borders. Our research groups have been working since eight years together with local communities in Ukrainian rural areas and documented a remarkable erosion of LEK during the Soviet times, yet an extraordinary surviving biocultural diversity occurs; the ongoing military occupation of Ukraine could further threaten this heritage. While citizens’ attention now should be on effectively supporting those who are experiencing hardships during this traumatic time, ethnobiologists will be called hopefully soon to directly participate in rebuilding the biocultural “cobwebs” damaged by the military operations
Position paper of the Italian Association of Medical Oncology on the impact of COVID-19 on Italian oncology and the path forward: the 2021 Matera statement
The coronavirus disease 2019 (COVID-19) pandemic has severely affected cancer care and research by disrupting the prevention and treatment paths as well as the preclinical, clinical, and translational research ecosystem. In Italy, this has been particularly significant given the severity of the pandemic's impact and the intrinsic vulnerabilities of the national health system. However, whilst detrimental, disruption can also be constructive and may stimulate innovation and progress. The Italian Association of Medical Oncology (AIOM) has recognized the impact of COVID-19 on cancer care continuum and research and proposes the '2021 Matera statement' which aims at providing pragmatic guidance for policymakers and health care institutions to mitigate the impact of the global health crisis on Italian oncology and design the recovery plan for the post-pandemic scenario. The interventions are addressed both to the pillars (prevention, diagnosis, treatment, follow-up, health care professionals) and foundations of cancer care (communication and care relationship, system organization, resources, research, networking). The priorities to be implemented can be summarized in the MATERA acronym: Multidisciplinarity; Access to cancer care; Telemedicine and Territoriality; Equity, ethics, education; Research and resources; Alliance between stakeholders and patients
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