scholarly journals Hemodynamic forces can be accurately measured in vivo with optical tweezers

2017 ◽  
Vol 28 (23) ◽  
pp. 3252-3260 ◽  
Author(s):  
Sébastien Harlepp ◽  
Fabrice Thalmann ◽  
Gautier Follain ◽  
Jacky G. Goetz
Keyword(s):  
Optical Tweezers ◽  
Cell Biology ◽  
Accurate Determination ◽  
Force Measurements ◽  
Hemodynamic Forces ◽  
Drag Forces ◽  
Measured Flow ◽  
Living Organisms

Force sensing and generation at the tissue and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows noninvasive probing of piconewton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles lie in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such a method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.

scholarly journals Hemodynamic forces can be accurately measured in vivo with optical tweezers

2017 ◽  
Author(s):  
Sébastien Harlepp ◽  
Fabrice Thalmann ◽  
Gautier Follain ◽  
Jacky G. Goetz
Keyword(s):  
Optical Tweezers ◽  
Cell Biology ◽  
Accurate Determination ◽  
Force Measurements ◽  
Hemodynamic Forces ◽  
Non Invasive ◽  
Drag Forces ◽  
Measured Flow ◽  
Living Organisms

AbstractForce sensing and generation at the tissular and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows non-invasive probing of pico-Newton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles rely in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here, we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether, this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.

scholarly journals Harnessing PET to track micro- and nanoplastics in vivo

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Outi Keinänen ◽  
Eric J. Dayts ◽  
Cindy Rodriguez ◽  
Samantha M. Sarrett ◽  
James M. Brennan ◽  
...  
Keyword(s):  
Sea Water ◽  
Accurate Determination ◽  
Nuclear Imaging ◽  
Imaging Data ◽  
Biodistribution Studies ◽  
Positron Emission ◽  
20 Nm ◽  
Pharmacokinetic Behavior

AbstractThe proliferation of plastics in the environment continues at an alarming rate. Plastic particles have been found to be persistent and ubiquitous pollutants in a variety of environments, including sea water, fresh water, soil, and air. In light of this phenomenon, the scientific and medical communities have become increasingly wary of the dangers posed to human health by chronic exposure to microplastics (< 5 mm diameter) and nanoplastics (< 100 nm diameter). A critical component of the study of the health effects of these pollutants is the accurate determination of their pharmacokinetic behavior in vivo. Herein, we report the first use of molecular imaging to track polystyrene (PS) micro- and nanoplastic particles in mammals. To this end, we have modified PS particles of several sizes—diameters of 20 nm, 220 nm, 1 µm, and 6 µm—with the chelator desferrioxamine (DFO) and radiolabeled these DFO-bearing particles with the positron-emitting radiometal zirconium-89 (89Zr; t1/2 ~ 3.3 d). Subsequently, positron emission tomography (PET) was used to visualize the biodistribution of these radioplastics in C57BL/6J mice at 6, 12, 24, and 48 h after ingestion. The imaging data reveal that the majority of the radioplastics remain in the gastrointestinal tract and are eliminated through the feces by 48 h post-ingestion, a result reinforced by acute biodistribution studies. Ultimately, this work suggests that nuclear imaging—and PET in particular—can be a sensitive and effective tool in the urgent and rapidly growing effort to study the in vivo behavior and potential toxicity of micro- and nanoplastics.

Sensitive and accurate determination of neurotransmitters from in vivo rat brain microdialysate of Parkinson's disease using in situ ultrasound-assisted derivatization dispersive liquid–liquid microextraction by UHPLC-MS/MS

RSC Advances ◽  
2016 ◽  
Vol 6 (110) ◽  
pp. 108635-108644 ◽  
Author(s):  
Xian-En Zhao ◽  
Yongrui He ◽  
Ping Yan ◽  
Na Wei ◽  
Renjun Wang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Rat Brain ◽  
Accurate Determination ◽  
Ultrasound Assisted ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

In situ UA-DDLLME coupled with UHPLC-MS/MS has been developed for simultaneous determination of neurotransmitters and baicalein from Parkinson's disease rats.

scholarly journals Calibration of Optical Tweezers for In Vivo Force Measurements: How do Different Approaches Compare?

2014 ◽  
Vol 107 (6) ◽  
pp. 1474-1484 ◽  
Author(s):  
Yonggun Jun ◽  
Suvranta K. Tripathy ◽  
Babu R.J. Narayanareddy ◽  
Michelle K. Mattson-Hoss ◽  
Steven P. Gross
Keyword(s):  
Optical Tweezers ◽  
Force Measurements

Use of 13C-labeled glucose for estimating glucose oxidation: some design considerations

1987 ◽  
Vol 63 (5) ◽  
pp. 1725-1732 ◽  
Author(s):  
J. J. Robert ◽  
J. Koziet ◽  
D. Chauvet ◽  
D. Darmaun ◽  
J. F. Desjeux ◽  
...  
Keyword(s):  
Glucose Oxidation ◽  
Accurate Determination ◽  
Metabolic States ◽  
Series Of Experiments ◽  
Time Required ◽  
Infusion Protocol ◽  
The Ideal ◽  
Expired Air

Use of 13C-labeled glucose for estimating in vivo rates of glucose oxidation faces several difficulties, particularly the accurate determination of the output of 13C in expired air. In an investigation of wholebody glucose metabolism in healthy adult humans, using a continuous intravenous infusion of D-[U-13C]glucose, we found that a precise estimate of the rate of glucose oxidation was difficult to achieve when the study included infusions with unlabeled glucose. Problems arose 1) as a result of the slow rate at which the 13CO2 released by glucose oxidation reaches an equilibrium in expired air CO2 and 2) due to the contribution to 13CO2 output by the natural 13C in the unlabeled glucose that was infused. In a subsequent series of experiments in healthy young adults, we found that the entry of 13CO2 released by the tissues into the bicarbonate pool and into the expired air is relatively slow and a tracer infusion protocol of approximately 6 h is required for determination of glucose oxidation. This applies when metabolic states are changed acutely during the experiment or when unlabeled glucose is infused. However, for resting subjects in the basal postabsorptive state we confirmed that the time required to achieve a steady state in the 13C enrichment of expired air can be shortened significantly by the use of a NaH13CO3 priming dose, even when this dose varies from the ideal.

scholarly journals Targeted LC-MS/MS platform for the comprehensive determination of peptides in the kallikrein-kinin system

2021 ◽  
Author(s):  
Tanja Gangnus ◽  
Bjoern B. Burckhardt
Keyword(s):  
Healthy Volunteers ◽  
Clinical Symptoms ◽  
Matrix Effects ◽  
Accurate Determination ◽  
Kinin System ◽  
Carry Over ◽  
Kallikrein Kinin System ◽  
The Impact

AbstractThe kallikrein-kinin system (KKS) is involved in many physiological and pathophysiological processes and is assumed to be connected to the development of clinical symptoms of angioedema or COVID-19, among other diseases. However, despite its diverse role in the regulation of physiological and pathophysiological functions, knowledge about the KKS in vivo remains limited. The short half-lives of kinins, their low abundance and structural similarities and the artificial generation of the kinin bradykinin greatly hinder reliable and accurate determination of kinin levels in plasma. To address these issues, a sensitive LC-MS/MS platform for the comprehensive and simultaneous determination of the four active kinins bradykinin, kallidin, des-Arg(9)-bradykinin and des-Arg(10)-kallidin and their major metabolites bradykinin 2-9, bradykinin 1-7 and bradykinin 1-5 was developed. This platform was validated according to the bioanalytical guideline of the US Food and Drug Administration regarding linearity, accuracy, precision, sensitivity, carry-over, recovery, parallelism, matrix effects and stability in plasma of healthy volunteers. The validated platform encompassed a broad calibration curve range from 2.0–15.3 pg/mL (depending on the kinin) up to 1000 pg/mL, covering the expected concentrations in disease states. No source-dependent matrix effects were identified, and suitable stability of the analytes in plasma was observed. The applicability of the developed platform was proven by the determination of endogenous levels in healthy volunteers, whose plasma kinin levels were successfully detected in the low pg/mL range. The established platform facilitates the investigation of kinin-mediated diseases (e.g. angioedema, COVID-19) and enables the assessment of the impact of altered enzyme activities on the formation or degradation of kinins. Graphical abstract

scholarly journals A computational method for determining XBT depths

Ocean Science ◽  
2011 ◽  
Vol 7 (6) ◽  
pp. 733-743 ◽  
Author(s):  
J. Stark ◽  
J. Gorman ◽  
M. Hennessey ◽  
F. Reseghetti ◽  
J. Willis ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Accurate Determination ◽  
Computational Method ◽  
Complex Flow ◽  
Drag Forces ◽  
Turbulent Transition ◽  
Flow Phenomena ◽  
A New Technique ◽  
Ocean Environment

Abstract. A new technique for determining the depth of expendable bathythermographs (XBTs) is developed. This new method uses a forward-stepping calculation which incorporates all of the forces on the XBT devices during their descent. Of particular note are drag forces which are calculated using a new drag coefficient expression. That expression, obtained entirely from computational fluid dynamic modeling, accounts for local variations in the ocean environment. Consequently, the method allows for accurate determination of depths for any local temperature environment. The results, which are entirely based on numerical simulation, are compared with the experiments of LM Sippican T-5 XBT probes. It is found that the calculated depths differ by less than 3% from depth estimates using the standard fall-rate equation (FRE). Furthermore, the differences decrease with depth. The computational model allows an investigation of the fluid flow patterns along the outer surface of the probe as well as in the interior channel. The simulations take account of complex flow phenomena such as laminar-turbulent transition and flow separation.

Optical manipulation of single molecules in the living cell

2014 ◽  
Vol 16 (25) ◽  
pp. 12614-12624 ◽  
Author(s):  
Kamilla Norregaard ◽  
Liselotte Jauffred ◽  
Kirstine Berg-Sørensen ◽  
Lene B. Oddershede
Keyword(s):  
Optical Tweezers ◽  
Living Cell ◽  
Single Molecules ◽  
Optical Manipulation ◽  
Force Measurements

Optical tweezers are the only nano-tools capable of manipulating and performing force-measurements on individual molecules and organelles inside the living cell. We present methodologies for in vivo calibration and exciting recent results.

scholarly journals Highly sensitive force measurements in an optically generated, harmonic hydrodynamic trap

eLight ◽  
2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Iliya D. Stoev ◽  
Benjamin Seelbinder ◽  
Elena Erben ◽  
Nicola Maghelli ◽  
Moritz Kreysing
Keyword(s):  
Optical Tweezers ◽  
Cell Biology ◽  
Magnetic Beads ◽  
Optical Control ◽  
Force Measurements ◽  
Force Extension ◽  
Thermal Limit ◽  
One Dimensional ◽  
Highly Sensitive ◽  
Trapping Method

AbstractThe use of optical tweezers to measure forces acting upon microscopic particles has revolutionised fields from material science to cell biology. However, despite optical control capabilities, this technology is highly constrained by the material properties of the probe, and its use may be limited due to concerns about the effect on biological processes. Here we present a novel, optically controlled trapping method based on light-induced hydrodynamic flows. Specifically, we leverage optical control capabilities to convert a translationally invariant topological defect of a flow field into an attractor for colloids in an effectively one-dimensional harmonic, yet freely rotatable system. Circumventing the need to stabilise particle dynamics along an unstable axis, this novel trap closely resembles the isotropic dynamics of optical tweezers. Using magnetic beads, we explicitly show the existence of a linear force-extension relationship that can be used to detect femtoNewton-range forces with sensitivity close to the thermal limit. Our force measurements remove the need for laser-particle contact, while also lifting material constraints, which renders them a particularly interesting tool for the life sciences and engineering.

scholarly journals Case Report: Concomitant Alzheimer's and Lewy-Related Pathology Extending the Spectrum of Underlying Pathologies of Corticobasal Syndrome

2021 ◽  
Vol 15 ◽  
Author(s):  
Michaela Kaiserová ◽  
Katerina Menšíková ◽  
Lucie Tučková ◽  
Petr Hluštík ◽  
Petr Kaňovský
Keyword(s):  
Histopathological Examination ◽  
Accurate Determination ◽  
Corticobasal Degeneration ◽  
Intermediate Stage ◽  
Corticobasal Syndrome ◽  
Lewy Body Pathology ◽  
Jakob Disease ◽  
Cortical Involvement

Corticobasal syndrome (CBS) is clinically characterized by progressive asymmetric rigidity and apraxia together with symptoms suggestive of cortical involvement and basal ganglia dysfunction. The spectrum of neurodegenerative diseases that can manifest with CBS is wide. The associations of CBS with corticobasal degeneration, progressive supranuclear palsy, Alzheimer's disease, frontotemporal lobar degenerations, Creutzfeldt–Jakob disease, or diffuse Lewy body pathology have been reported. We describe the case of a 71-year-old woman with CBS. The histopathological examination of brain tissue revealed concomitant pathology corresponding to the limbic stage of Lewy-related pathology and the intermediate stage of Alzheimer's-type pathology. To date, there have been only a few cases with a similar combination of pathology manifesting with the CBS phenotype that have been described in the literature. The extent and distribution of pathological changes in these cases were somewhat different from ours, and significance for clinical manifestation was attributed to only one of these pathologies. In our case, we assume that both types of pathology contributed to the development of the disease, considering the presumed specific spread of both types of pathological processes according to Braak's staging. Our case expands the spectrum of neurodegenerative pathological processes that may manifest with the typical CBS phenotype. Also, it points out the importance of identifying specific biomarkers that would enable more accurate in vivo differential diagnosis and more accurate determination of the underlying pathological processes of these diseases.

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