211 research outputs found
Apparent stiffness of vimentin intermediate filaments in living cells and its relation with other cytoskeletal polymers
The cytoskeleton is a complex network of interconnected biopolymers intimately involved in the generation and transmission of forces. Several mechanical properties of microtubules and actin filaments have been extensively explored in cells. In contrast, intermediate filaments (IFs) received comparatively less attention despite their central role in defining cell shape, motility and adhesion during physiological processes as well as in tumor progression. Here, we explored relevant biophysical properties of vimentin IFs in living cells combining confocal microscopy and a filament tracking routine that allows localizing filaments with ~20 nm precision. A Fourier-based analysis showed that IFs curvatures followed a thermal-like behavior characterized by an apparent persistence length (lp*) similar to that measured in aqueous solution. Additionally, we determined that certain perturbations of the cytoskeleton affect lp* and the lateral mobility of IFs as assessed in cells in which either the microtubule dynamic instability was reduced or actin filaments were partially depolymerized. Our results provide relevant clues on how vimentin IFs mechanically couple with microtubules and actin filaments in cells and support a role of this network in the response to mechanical stress.Fil: Smoler, Mariano. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica BiolĂłgica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica BiolĂłgica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Coceano, Giovanna. Royal Institute of Technology; SueciaFil: Testa, Ilaria. Royal Institute of Technology; SueciaFil: Bruno, Luciana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Calculo. - Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de Calculo; ArgentinaFil: Levi, Valeria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica BiolĂłgica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica BiolĂłgica de la Facultad de Ciencias Exactas y Naturales; Argentin
Dwarf spheroidal satellites of M31: I. Variable stars and stellar populations in Andromeda XIX
We present B,V time-series photometry of Andromeda XIX (And XIX), the most
extended (half-light radius of 6.2') of Andromeda's dwarf spheroidal
companions, that we observed with the Large Binocular Cameras at the Large
Binocular Telescope. We surveyed a 23'x 23' area centered on And XIX and
present the deepest color magnitude diagram (CMD) ever obtained for this
galaxy, reaching, at V~26.3 mag, about one magnitude below the horizontal
branch (HB). The CMD shows a prominent and slightly widened red giant branch,
along with a predominantly red HB, which, however, extends to the blue to
significantly populate the classical instability strip. We have identified 39
pulsating variable stars, of which 31 are of RR Lyrae type and 8 are Anomalous
Cepheids (ACs). Twelve of the RR Lyrae variables and 3 of the ACs are located
within And XIX's half light radius. The average period of the fundamental mode
RR Lyrae stars ( = 0.62 d, \sigma= 0.03 d) and the period-amplitude
diagram qualify And XIX as an Oosterhoff-Intermediate system. From the average
luminosity of the RR Lyrae stars ( = 25.34 mag, \sigma= 0.10 mag) we
determine a distance modulus of (m-M)= mag in a scale where
the distance to the Large Magellanic Cloud (LMC) is mag. The ACs
follow a well defined Period-Wesenheit (PW) relation that appears to be in very
good agreement with the PW relationship defined by the ACs in the LMC.Comment: accepted for publication in Ap
Clinical use of contrast-enhanced ultrasound beyond the liver: a focus on renal, splenic, and pancreatic applications
Contrast-enhanced ultrasound (CEUS) is a relatively novel, but increasingly used, diagnostic imaging modality. In recent years, due to its safety, quickness, and repeatability, several studies have demonstrated the accuracy, specificity, and sensitivity of CEUS. The European Federation of Societies for Ultrasound in Medicine and Biology has recently updated the previous guidelines from 2012 for the use of CEUS in non-hepatic applications. This review deals with the clinical use and applications of CEUS for the evaluation of non-hepatic abdominal organs, focusing on renal, splenic, and pancreatic applications
Late Onset Cobalamin Disorder and Hemolytic Uremic Syndrome: A Rare Cause of Nephrotic Syndrome
Hemolytic uremic syndrome (HUS) is an unrare and severe thrombotic microangiopathy (TMA) caused by several pathogenetic mechanisms among which Shiga toxin-producing Escherichia coli infections and complement dysregulation are the most common. However, very rarely and particularly in neonates and infants, disorders of cobalamin metabolism (CblC) can present with or be complicated by TMA. Herein we describe a case of atypical HUS (aHUS) related to CblC disease which first presented in a previously healthy boy at age of 13.6 years. The clinical picture was initially dominated by nephrotic range proteinuria and severe hypertension followed by renal failure. The specific treatment with high dose of hydroxycobalamin rapidly obtained the remission of TMA and the complete recovery of renal function. We conclude that plasma homocysteine and methionine determinations together with urine organic acid analysis should be included in the diagnostic work-up of any patient with TMA and/or nephrotic syndrome regardless of age
The Experience of Pelvic Floor Muscle Training in People with Urinary Incontinence: A Qualitative Study
Pelvic Floor Muscle Training (PFMT) is the first primary solution to improve urinary incontinence (UI) symptoms, but many challenges stems from certain PFMT-related practices. Exploring PFMT experience will help to increase treatment satisfaction, enjoyment, and empowerment. Hence, the aim of this study was to investigate the experience of pelvic floor muscle training (PFMT) in Italian people with UI. A qualitative semi-structured interview study was conducted. The interviewsâ transcriptions were analysed using a constructionist epistemology lens and adopting the âReflexive Thematic Analysisâ. Sixteen Italian participants (Women N = 10, Men = 6) with UI who experienced PFMT were interviewed. Four themes were generated: (1) âLearn to Control the Unconscious Consciouslyâ as participants learned to control continence through active exercises; (2) âStarting PFMT, Changing Mindâ as they realised they can have an active role in managing their condition; (3) âInto the unknown intimacyâ, as they bridged the gap in their (mis)understanding of the pelvic floor area, overcoming the discomfort linked to intimacy; (4) The Importance of Not Being Alone in this Processâ, as the participants emphasised the paramount role of the physiotherapists in the healing process. To conclude, in people with UI, PFMT enhanced pelvic floor knowledge and understanding, fostering awareness, positive mindset, and symptom relief. The physiotherapist's pivotal role as an educator and empathetic guide in exercise programs, along with a preference for active exercises. Overall, our results proved that PFMT has positive consequences in peopleâs beliefs and mindset about and in the management of UI
A set of monomeric near-infrared fluorescent proteins for multicolor imaging across scales
Bright monomeric near-infrared (NIR) fluorescent proteins (FPs) are in high demand as protein tags for multicolor microscopy and in vivo imaging. Here we apply rational design to engineer a complete set of monomeric NIR FPs, which are the brightest genetically encoded NIR probes. We demonstrate that the enhanced miRFP series of NIR FPs, which combine high effective brightness in mammalian cells and monomeric state, perform well in both nanometer-scale imaging with diffraction unlimited stimulated emission depletion (STED) microscopy and centimeter-scale imaging in mice. In STED we achieve -40nm resolution in live cells. In living mice we detect -10(5) fluorescent cells in deep tissues. Using spectrally distinct monomeric NIR FP variants, we perform two-color live-cell STED microscopy and two-color imaging in vivo. Having emission peaks from 670nm to 720nm, the next generation of miRFPs should become versatile NIR probes for multiplexed imaging across spatial scales in different modalities.Peer reviewe
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