a-simple-method-for-automated-solid-phase-extraction-water-samples

A Simple Method for Automated Solid Phase Extraction of Water Samples for Immunological Analysis of Small Pollutants

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and ...

senescence-detection-using-reflected-light-adipose-stromal-vascular

Senescence Detection Using Reflected Light in Adipose Stromal Vascular Fraction

Cellular senescence is a stress-induced state characterized by permanent cell-cycle arrest and the development of a distinctive secretory profile that ...

Soft tissue modeling is of key importance in medical robotics and simulation. In the case of percutaneous operations, a fine model of layers transitions and target tissues is required. However, the nature and the variety of these tissues is such that this problem is extremely complex. In this article, we propose a method to estimate the interaction between in vivo tissues and a surgical needle. The online robust estimation of a varying parameters model is achieved during an insertion in standard operating conditions.

Online robust model estimation during in vivo needle insertions.

Low-density lipoprotein (LDL) is an important carrier of plasma cholesterol and triglycerides whose concentration is regulated by the liver parenchymal cells. Abnormal LDL regulation is thought to cause atherosclerosis, while viral binding to LDL has been suggested to facilitate hepatitis C infection. Primary hepatocytes quickly lose the ability to clear LDL during in vitro culture. Here we show that the coculture of hepatocytes with liver sinusoidal endothelial cells (LSEC) significantly increases the ability of hepatocytes to uptake LDL in vitro. LDL uptake does not increase when hepatocytes are cocultured with other cell types such as fibroblasts or umbilical vein endothelial cells. We find that LSECs induce the hepatic expression of the LDL receptor and the epidermal growth factor receptor. In addition, while hepatocytes in single culture did not take up hepatitis C virus (HCV)-like particles, the hepatocytes cocultured with LSECs showed a high level of HCV-like particle uptake. We suggest that coculture with LSECs induces the emergence of a sinusoidal surface in primary hepatocytes conducive to the uptake of HCV-like particles. In conclusion, our findings describe a novel model of polarized hepatocytes in vitro that can be used for the study of LDL metabolism and hepatitis C infection.

Liver endothelial cells promote LDL-R expression and the uptake of HCV-like particles in primary rat and human hepatocytes.

Low density Lipoprotein (LDL) ist ein wichtiger Tr&auml;ger des Plasma-Cholesterin und Triglyceride, deren Konzentration von Lungenparenchym Leberzellen reguliert wird. Abnorme LDL-Verordnung ist vermutlich Arteriosklerose, zu verursachen, w&auml;hrend virale Bindung an LDL vorgeschlagen wurde, Hepatitis-C-Infektion zu erleichtern. Prim&auml;re Hepatozyten verlieren schnell die F&auml;higkeit LDL w&auml;hrend der in-vitro-Kultur gel&ouml;scht. Hier zeigen wir, dass die Coculture der Hepatozyten mit Leber sinusf&ouml;rmige Endothelzellen (LSEC) signifikant die F&auml;higkeit der Hepatozyten zu Aufnahme LDL in-vitro erh&ouml;ht. LDL-Aufnahme wird nicht erh&ouml;ht, wenn Hepatozyten mit anderen Zelltypen wie Fibroblasten cocultured sind oder Nabelschnur vein endotheliale Zellen. Wir finden, dass LSECs den Leber Ausdruck des LDL-Rezeptors und den epidermalen Wachstumsfaktor-Rezeptor hervorrufen. Dar&uuml;ber hinaus, doch obwohl Hepatozyten in einzelne Kultur nicht auf Hepatitis C-Virus (HCV) - wie Partikel, die Hepatozyten mit LSECs cocultured ein hohes Ma&szlig; an HCV zeigte - wie Partikel Aufnahme. Wir schlagen vor, da&szlig; Coculture mit LSECs die Entstehung einer sinusf&ouml;rmigen Oberfl&auml;che in prim&auml;re Hepatozyten f&ouml;rderlich f&uuml;r die Aufnahme von HCV-&auml;hnliche Partikel hervorruft. Zusammenfassend beschreiben unsere Erkenntnisse ein neuartiges Modell von in-vitro-polarisierten Hepatozyten, die f&uuml;r das Studium der LDL-Stoffwechsel- und Hepatitis-C-Infektionen verwendet werden kann.

Endotheliale Leberzellen f&ouml;rdern LDL-R Ausdruck und die Aufnahme von HCV-&auml;hnliche Partikel in prim&auml;ren Ratte und menschlichen Hepatozyten.

Isolated perfusion models can yield important data regarding metabolism of the skin. An effective model must remain stable during perfusion but respond appropriately to metabolic and vascular stimuli. We describe the design and characterization of a tubed superficial epigastric isolated perfusion flap.

Isolated perfusion of a tubed superficial epigastric flap in a rodent model.

Oxygen is an important component of the cellular microenvironment, mediating cell survival, differentiation, and function. Oxygen supply is a limiting factor during culture of highly metabolic cells such as hepatocytes. Here we present a simple formulation of a fluorocarbon-based oxygen carrier embedded in collagen gel that increases oxygen concentration in culture 6-fold. Rat hepatocytes cultured on oxygen carrier-collagen showed a significant increase in viability and function. Cytochrome P450IA1 activity was increased by 140% in serum-free cultures and by 820% in serum-containing cultures. The significantly higher hepatocellular function on oxygen carrier-collagen matrix persisted and increased during long-term culture. Long-term albumin secretion was increased by 350% in serum-free cultures and by 166% in serum-containing culture. Long-term urea secretion was increased by 79% in serum-free cultures and by 76% in serum-containing cultures. We conclude that oxygen supply may limit hepatocyte function in vitro. This limitation can be overcome by addition of an oxygen carrier to the extracellular matrix. Culture of hepatocytes on oxygen-carrying matrix mimics the oxygen-rich environment of the liver and provides a simple method for enhanced long-term function.

A novel formulation of oxygen-carrying matrix enhances liver-specific function of cultured hepatocytes.

Sauerstoff ist ein wichtiger Bestandteil der zellul&auml;ren Mikromilieu, Vermittlung, Zelle &uuml;berleben, Differenzierung und Funktion. Sauerstoffversorgung ist ein limitierender Faktor w&auml;hrend der Kultur der hoch metabolische Zellen wie Hepatozyten. Hier pr&auml;sentieren wir eine einfache Formulierung einer Fluorcarbon-basierte Sauerstoff-Fluggesellschaft in Kollagengel, das 6-fold erh&ouml;ht die Sauerstoffkonzentration in der Kultur eingebettet. Ratte Hepatozyten kultiviert auf Sauerstoff F&ouml;rdermaschine-Collagen zeigten eine deutliche Steigerung in Lebensf&auml;higkeit und Funktion. Cytochrom P450IA1 Aktivit&auml;t wurde erh&ouml;ht, um 140 Prozent in serumfreien Kulturen und um 820 % in serumhaltigem Kulturen. Die deutlich h&ouml;here hepatozellul&auml;re-Funktion auf Sauerstoff-Tr&auml;ger-Kollagen-Matrix beibehalten und w&auml;hrend Langzeitkultur erh&ouml;ht. Langfristige Albumin-Sekretion stieg um 350 % in serumfreien Kulturen und um 166 % im Serum-haltigen Kultur. Langfristige Harnstoff-Sekretion wurde erh&ouml;ht, 79 % in serumfreien Kulturen und 76 % in serumhaltigem Kulturen. Wir schlie&szlig;en, dass die Sauerstoffversorgung Hepatozyten-Funktion, die in-vitro beschr&auml;nken kann. Diese Einschr&auml;nkung kann durch Zugabe von ein Sauerstoff-Carrier in der extrazellul&auml;ren Matrix &uuml;berwunden werden. Kultur der Hepatozyten auf Sauerstoff-tragenden Matrix ahmt das sauerstoffreiches Umfeld der Leber und bietet eine einfache Methode f&uuml;r verbesserte langfristige Funktion.

Eine neuartige Formulierung von Sauerstoff-tragenden Matrix erh&ouml;ht die Leber-spezifische Funktion des kultivierten Hepatozyten.

Information on protein localization on the subcellular level is important to map and characterize the proteome and to better understand cellular functions of proteins. Here we report on a pilot study of 466 proteins in three human cell lines aimed to allow large scale confocal microscopy analysis using protein-specific antibodies. Approximately 3000 high resolution images were generated, and more than 80% of the analyzed proteins could be classified in one or multiple subcellular compartment(s). The localizations of the proteins showed, in many cases, good agreement with the Gene Ontology localization prediction model. This is the first large scale antibody-based study to localize proteins into subcellular compartments using antibodies and confocal microscopy. The results suggest that this approach might be a valuable tool in conjunction with predictive models for protein localization.

Toward a confocal subcellular atlas of the human proteome.

Steatosis decreases survival of liver grafts after transplantation due to poorly understood mechanisms. We examined the effect of steatosis on the survival of liver grafts in a rat liver transplantation model and the viability of cultured rat hepatocytes after hypoxia and reoxygenation.

Steatosis reversibly increases hepatocyte sensitivity to hypoxia-reoxygenation injury.

Steatose verringert &Uuml;berleben der Leber Transplantate nach Transplantation aufgrund schlecht Mechanismen verstanden. Wir untersuchten den Effekt einer Steatose auf das &Uuml;berleben der Leber-Prothesen in einem Rattenleberzellen-Transplantation-Modell und die Lebensf&auml;higkeit der kultivierten Ratte Hepatozyten nach Hypoxie und Reoxygenation.

Steatose erh&ouml;ht umkehrbar Hepatozyten Empfindlichkeit gegen Hypoxie-Reoxygenation Verletzungen.

We present a microfluidic epithelial wound-healing assay that allows characterization of the effect of hepatocyte growth factor (HGF) on the regeneration of alveolar epithelium using a flow-focusing technique to create a regular wound in the epithelial monolayer. The phenotype of the epithelial cell was characterized using immunostaining for tight junction (TJ) proteins and transmission electron micrographs (TEMs) of cells cultured in the microfluidic system, a technique that is reported here for the first time. We demonstrate that alveolar epithelial cells cultured in a microfluidic environment preserve their phenotype before and after wounding. In addition, we report a wound-healing benefit induced by addition of HGF to the cell culture medium (19.2 vs. 13.5 μm h(-1) healing rate).

Microfluidic wound-healing assay to assess the regenerative effect of HGF on wounded alveolar epithelium.

The use of biomarkers to infer drug response in patients is being actively pursued, yet significant challenges with this approach, including the complicated interconnection of pathways, have limited its application. Direct empirical testing of tumor sensitivity would arguably provide a more reliable predictive value, although it has garnered little attention largely due to the technical difficulties associated with this approach. We hypothesize that the application of recently developed microtechnologies, coupled to more complex 3-dimensional cell cultures, could provide a model to address some of these issues. As a proof of concept, we developed a microfluidic device where spheroids of the serous epithelial ovarian cancer cell line TOV112D are entrapped and assayed for their chemoresponse to carboplatin and paclitaxel, two therapeutic agents routinely used for the treatment of ovarian cancer. In order to index the chemoresponse, we analyzed the spatiotemporal evolution of the mortality fraction, as judged by vital dyes and confocal microscopy, within spheroids subjected to different drug concentrations and treatment durations inside the microfluidic device. To reflect microenvironment effects, we tested the effect of exogenous extracellular matrix and serum supplementation during spheroid formation on their chemotherapeutic response. Spheroids displayed augmented chemoresistance in comparison to monolayer culturing. This resistance was further increased by the simultaneous presence of both extracellular matrix and high serum concentration during spheroid formation. Following exposure to chemotherapeutics, cell death profiles were not uniform throughout the spheroid. The highest cell death fraction was found at the center of the spheroid and the lowest at the periphery. Collectively, the results demonstrate the validity of the approach, and provide the basis for further investigation of chemotherapeutic responses in ovarian cancer using microfluidics technology. In the future, such microdevices could provide the framework to assay drug sensitivity in a timeframe suitable for clinical decision making.

Empirical chemosensitivity testing in a spheroid model of ovarian cancer using a microfluidics-based multiplex platform.

A fully automated and portable system for solid phase extraction (SPE) has been developed for the analysis of the natural hormone 17β-estradiol (E2) in environmental water by enzyme linked immuno-sorbent assay (ELISA). The system has been validated with de-ionized and artificial sea water as model samples and allowed for pre-concentration of E2 at levels of 1, 10 and 100ng/L with only 100ml of sample. Recoveries ranged from 24±3% to 107±6% depending on the concentration and sample matrix. The method successfully allowed us to determine the concentration of two seawater samples. A concentration of 15.1±0.3ng/L of E2 was measured in a sample obtained from a food production process, and 8.8±0.7ng/L in a sample from the Adriatic Sea. The system would be suitable for continuous monitoring of water quality as it is user friendly, and as the method is reproducible and totally compatible with the analysis of water sample by simple immunoassays and other detection methods such as biosensors.

Automated and portable solid phase extraction platform for immuno-detection of 17β-estradiol in water.

MRI-guided thermal ablations require reliable monitoring methods to ensure complete destruction of the diseased tissue while avoiding damage to the surrounding healthy tissue. Based on the fact that thermal ablations result in substantial changes in biomechanical properties, interventional MR elastography (MRE) dedicated to the monitoring of MR-guided thermal therapies is proposed here.

ArticleTotal : 2	Year
Publication title Cited by 2	2016
Publication title	2026

Article	Year
Online robust model estimation during in vivo needle insertions. Studies in health technology and informatics\| PubMed ID: 16404010	2006
Liver endothelial cells promote LDL-R expression and the uptake of HCV-like particles in primary rat and human hepatocytes. Hepatology (Baltimore, Md.)\| PubMed ID: 16440337	2006
Isolated perfusion of a tubed superficial epigastric flap in a rodent model. The Journal of surgical research\| PubMed ID: 16566940	2006
A novel formulation of oxygen-carrying matrix enhances liver-specific function of cultured hepatocytes. FASEB journal : official publication of the Federation of American Societies for Experimental Biology\| PubMed ID: 17077286	2006
Toward a confocal subcellular atlas of the human proteome. Molecular & cellular proteomics : MCP\| PubMed ID: 18029348	2008
Steatosis reversibly increases hepatocyte sensitivity to hypoxia-reoxygenation injury. The Journal of surgical research\| PubMed ID: 18599084	2009
Microfluidic wound-healing assay to assess the regenerative effect of HGF on wounded alveolar epithelium. Lab on a chip\| PubMed ID: 22146948	2012
Empirical chemosensitivity testing in a spheroid model of ovarian cancer using a microfluidics-based multiplex platform. Biomicrofluidics\| PubMed ID: 24403987	2013
Automated and portable solid phase extraction platform for immuno-detection of 17β-estradiol in water. Journal of chromatography. A\| PubMed ID: 25604269	2015
Interventional MR elastography for MRI-guided percutaneous procedures. Magnetic resonance in medicine\| PubMed ID: 25846380	2015
In Vitro Models to Mimic the Endothelial Barrier. Alternatives to laboratory animals : ATLA\| PubMed ID: 26256399	2015

Laurent Barbe

Biography

JoVE Journal Publications

Other Publications