Preliminary Mechanical Characterization of the Small Bowel for In Vivo Mobility

2010 ◽  
Author(s):  
Benjamin S. Terry ◽  
Jonathan A. Schoen ◽  
Allison B. Lyle ◽  
Mark E. Rentschler
Keyword(s):  
Small Bowel ◽  
Mechanical Characterization ◽  
Force Sensor ◽  
Migrating Motor Complex ◽  
Surrounding Tissue ◽  
Biaxial Test ◽  
Motor Complex

In this work we present test methods, devices, and preliminary results for the mechanical characterization of the small bowel for intraluminal mobility. Both active and passive forces that affect mobility are investigated. The active forces are generated by the migrating motor complex and the movement of muscular organs within and surrounding the peritoneal cavity. Passive forces develop from the biomechanical response of the tissue, the tribology of the mucosa, mucoadhesion, and the orientation and mass of surrounding tissue. Four investigative devices and testing methods to characterize the active and passive forces are presented in this work. These are: 1) A novel manometer and a force sensor array that measure forces generated by the migrating motor complex; 2) A biaxial test apparatus and method for characterizing the biomechanical properties of the duodenum, jejunum, and ileum; 3) A novel in vitro protocol and device designed to measure the force required to overcome mucoadhesion; 4) A novel tribometer that measures in vivo coefficient of friction between the mucus membrane and the robot surface.

scholarly journals Preliminary Mechanical Characterization of the Small Bowel for In Vivo Robotic Mobility

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Benjamin S. Terry ◽  
Allison B. Lyle ◽  
Jonathan A. Schoen ◽  
Mark E. Rentschler
Keyword(s):  
Small Bowel ◽  
Coefficient Of Friction ◽  
Axial Length ◽  
Mechanical Characterization ◽  
Biaxial Stress ◽  
Biaxial Test ◽  
The Mean

In this work we present test methods, devices, and preliminary results for the mechanical characterization of the small bowel for intra luminal robotic mobility. Both active and passive forces that affect mobility are investigated. Four investigative devices and testing methods to characterize the active and passive forces are presented in this work: (1) a novel manometer and a force sensor array that measure force per cm of axial length generated by the migrating motor complex, (2) a biaxial test apparatus and method for characterizing the biomechanical properties of the duodenum, jejunum, and ileum, (3) a novel in vitro device and protocol designed to measure the energy required to overcome the self-adhesivity of the mucosa, and (4) a novel tribometer that measures the in vivo coefficient of friction between the mucus membrane and the robot surface. The four devices are tested on a single porcine model to validate the approach and protocols. Mean force readings per cm of axial length of intestine that occurred over a 15 min interval in vivo were 1.34 ± 0.14 and 1.18 ± 0.22 N cm−1 in the middle and distal regions, respectively. Based on the biaxial stress/stretch tests, the tissue behaves anisotropically with the circumferential direction being more compliant than the axial direction. The mean work per unit area for mucoseparation of the small bowel is 0.08 ± 0.03 mJ cm−2. The total energy to overcome mucoadhesion over the entire length of the porcine small bowel is approximately 0.55 J. The mean in vivo coefficient of friction (COF) of a curved 6.97 cm2 polycarbonate sled on live mucosa traveling at 1 mm s−1 is 0.016 ± 0.002. This is slightly lower than the COF on excised tissue, given the same input parameters. We have initiated a comprehensive program and suite of test devices and protocols for mechanically characterizing the small bowel for in vivo mobility. Results show that each of the four protocols and associated test devices has successfully gathered preliminary data to confirm the validity of our test approach.

A microdialysis method allowing characterization of intercellular water space in humans

1987 ◽  
Vol 253 (2) ◽  
pp. E228-E231 ◽  
Author(s):  
P. Lonnroth ◽  
P. A. Jansson ◽  
U. Smith
Keyword(s):  
Glucose Concentration ◽  
Isotonic Saline ◽  
Surrounding Tissue ◽  
Glucose Levels ◽  
Water Space ◽  
Active Substances ◽  
Validation Experiments

To evaluate the usefulness of the tissue-microdialysis technique in humans, the glucose concentration in the intercellular water space was measured in the abdominal subcutaneous region in healthy subjects. A 30 X 0.3 mm dialysis fiber with a 3,000 MW cutoff was used. The dialysis catheter was calibrated in vivo by perfusing it with isotonic saline and four to five different glucose concentrations (0-5 mM). The perfusate was collected in 6-min fractions. Regression analysis of the results of the calibration yielded the perfusate glucose concentration, which was in equilibrium with the surrounding tissue. Validation experiments showed that this value could be precisely measured and represented the intercellular glucose concentration. The recovery of glucose in the dialysate (dialysate glucose concentration/medium) during the calibrations in vivo was only approximately one-half of that in vitro (recovery factors 0.28 vs. 0.44, respectively). Under steady-state conditions, the intercellular glucose concentration was similar to the glucose levels in the cubital vein. It is concluded that this microdialysis technique is a useful tool allowing measurements of metabolically active substances in the intercellular water space in vivo provided that the calibrations are properly performed.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

In vitro and in vivo characterization of graphene oxide coated porcine bone granules

Carbon ◽  
2016 ◽  
Vol 103 ◽  
pp. 291-298 ◽  
Author(s):  
Valeria Ettorre ◽  
Patrizia De Marco ◽  
Susi Zara ◽  
Vittoria Perrotti ◽  
Antonio Scarano ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
In Vivo Characterization

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

scholarly journals Functional Characterization of the mazEF Toxin-Antitoxin System in the Pathogenic Bacterium Agrobacterium tumefaciens

2021 ◽  
Vol 9 (5) ◽  
pp. 1107
Author(s):  
Wonho Choi ◽  
Yoshihiro Yamaguchi ◽  
Ji-Young Park ◽  
Sang-Hyun Park ◽  
Hyeok-Won Lee ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Physiological Function ◽  
Functional Characterization ◽  
Site Directed Mutagenesis ◽  
In Vitro Assays ◽  
Cell Growth Inhibition ◽  
The Right

Agrobacterium tumefaciens is a pathogen of various plants which transfers its own DNA (T-DNA) to the host plants. It is used for producing genetically modified plants with this ability. To control T-DNA transfer to the right place, toxin-antitoxin (TA) systems of A. tumefaciens were used to control the target site of transfer without any unintentional targeting. Here, we describe a toxin-antitoxin system, Atu0939 (mazE-at) and Atu0940 (mazF-at), in the chromosome of Agrobacterium tumefaciens. The toxin in the TA system has 33.3% identity and 45.5% similarity with MazF in Escherichia coli. The expression of MazF-at caused cell growth inhibition, while cells with MazF-at co-expressed with MazE-at grew normally. In vivo and in vitro assays revealed that MazF-at inhibited protein synthesis by decreasing the cellular mRNA stability. Moreover, the catalytic residue of MazF-at was determined to be the 24th glutamic acid using site-directed mutagenesis. From the results, we concluded that MazF-at is a type II toxin-antitoxin system and a ribosome-independent endoribonuclease. Here, we characterized a TA system in A. tumefaciens whose understanding might help to find its physiological function and to develop further applications.

scholarly journals Preclinical characterization of dostarlimab, a therapeutic anti-PD-1 antibody with potent activity to enhance immune function in in vitro cellular assays and in vivo animal models

mAbs ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 1954136
Author(s):  
Sujatha Kumar ◽  
Srimoyee Ghosh ◽  
Geeta Sharma ◽  
Zebin Wang ◽  
Marilyn R. Kehry ◽  
...  
Keyword(s):  
Animal Models ◽  
Immune Function ◽  
Cellular Assays ◽  
In Vivo Animal Models
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