scholarly journals Intelligent magnetic manipulation for gastrointestinal ultrasound

2019 ◽  
Vol 4 (31) ◽  
pp. eaav7725 ◽  
Author(s):  
Joseph C. Norton ◽  
Piotr R. Slawinski ◽  
Holly S. Lay ◽  
James W. Martin ◽  
Benjamin F. Cox ◽  
...  
Keyword(s):  
Closed Loop ◽  
Porcine Model ◽  
Diagnostic Endoscopy ◽  
Tissue Removal ◽  
Linear Probe ◽  
Tissue Surface ◽  
Gastrointestinal Ultrasound ◽  
Manual Manipulation

Diagnostic endoscopy in the gastrointestinal tract has remained largely unchanged for decades and is limited to the visualization of the tissue surface, the collection of biopsy samples for diagnoses, and minor interventions such as clipping or tissue removal. In this work, we present the autonomous servoing of a magnetic capsule robot for in situ, subsurface diagnostics of microanatomy. We investigated and showed the feasibility of closed-loop magnetic control using digitized microultrasound (μUS) feedback; this is crucial for obtaining robust imaging in an unknown and unconstrained environment. We demonstrated the functionality of an autonomous servoing algorithm that uses μUS feedback, both on benchtop trials and in vivo in a porcine model. We have validated this magnetic μUS servoing in instances of autonomous linear probe motion and were able to locate markers in an agar phantom with 1.0 ± 0.9 mm position accuracy using a fusion of robot localization and μUS image information. This work demonstrates the feasibility of closed-loop robotic μUS imaging in the bowel without the need for either a rigid physical link between the transducer and extracorporeal tools or complex manual manipulation.

Direct Measurements of Intracellular Elemental Composition Utilizing a New Approach to Freezing In Vivo

1985 ◽  
Vol 43 ◽  
pp. 10-13 ◽  
Author(s):  
Avril V. Somlyo ◽  
Meredith Bond ◽  
John C. Silcox ◽  
A.P. Somlyo
Keyword(s):  
Elemental Composition ◽  
Experimental Conditions ◽  
New Approach ◽  
Direct Measurements ◽  
Pharmacological Studies ◽  
Tissue Surface ◽  
Clamping Device ◽  
Made In

Many biological experiments can be successfully carried out on tissues isolated under well-defined experimental conditions, but for some physiological or pharmacological studies, knowledge of the in vivo elemental composition and/or structure is essential. We have developed a method for rapid freezing of organs in situ, with a new spring-loaded, hand held, clamping device that holds two apposing melting Freon popsicles (Fig. 5). The melting Freon surfaces that contact the tissue are at the melting point of Freon 22, and these mold to the unevenness of the tissue surface. Rapidly frozen samples of liver, pancreas or mesentery were obtained by placing an anesthetized rat in a cloth sling over an environmental chamber kept at 37°C, 100% humidity (Fig. 5). A small incision is made in the abdomen, and the abdominal wall is manipulated until a lobe of liver protrudes through the incision, while taking care not to touch the surface of the organ. Immediately, the Freon clamper is activated to snap freeze the tissue.

scholarly journals Endoscopic Microscopy

2002 ◽  
Vol 18 (5-6) ◽  
pp. 269-291 ◽  
Author(s):  
Konstantin Sokolov ◽  
Kung-Bin Sung ◽  
Tom Collier ◽  
Anne Clark ◽  
Dizem Arifler ◽  
...  
Keyword(s):  
Optical Imaging ◽  
Cancer Detection ◽  
Low Cost ◽  
Basic Principles ◽  
Epithelial Cancers ◽  
Research Activities ◽  
Tissue Removal ◽  
Tissue Surface ◽  
Potential Applications

In vivo endoscopic optical microscopy provides a tool to assess tissue architecture and morphology with contrast and resolution similar to that provided by standard histopathology – without need for physical tissue removal. In this article, we focus on optical imaging technologies that have the potential to dramatically improve the detection, prevention, and therapy of epithelial cancers. Epithelial pre-cancers and cancers are associated with a variety of morphologic, architectural, and molecular changes, which currently can be assessed only through invasive, painful biopsy. Optical imaging is ideally suited to detecting cancer-related alterations because it can detect biochemical and morphologic alterations with sub-cellular resolution throughout the entire epithelial thickness. Optical techniques can be implemented non-invasively, in real time, and at low cost to survey the tissue surface at risk. Our manuscript focuses primarily on modalities that currently are the most developed: reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). However, recent advances in fluorescence-based endoscopic microscopy also are reviewed briefly. We discuss the basic principles of these emerging technologies and their current and potential applications in early cancer detection. We also present research activities focused on development of exogenous contrast agents that can enhance the morphological features important for cancer detection and that have the potential to allow vital molecular imaging of cancer-related biomarkers. In conclusion, we discuss future improvements to the technology needed to develop robust clinical devices.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Three-Dimensional Subcellular Organization of Hepatocytes in Intact Liver: Simultaneous Visualization of Cytoskeletal and Membrane Markers by Confocal Microscopy

1996 ◽  
Vol 54 ◽  
pp. 288-289
Author(s):  
Greg V. Martin ◽  
Ann L. Hubbard
Keyword(s):  
Three Dimensional ◽  
Integral Membrane Proteins ◽  
Polarized Secretion ◽  
Microscope Images ◽  
Computer Aided ◽  
Intracellular Organelles ◽  
Cytoskeletal Elements ◽  
Simultaneous Visualization

The microtubule (MT) cytoskeleton is necessary for many of the polarized functions of hepatocytes. Among the functions dependent on the MT-based cytoskeleton are polarized secretion of proteins, delivery of endocytosed material to lysosomes, and transcytosis of integral plasma membrane (PM) proteins. Although microtubules have been shown to be crucial to the establishment and maintenance of functional and structural polarization in the hepatocyte, little is known about the architecture of the hepatocyte MT cytoskeleton in vivo, particularly with regard to its relationship to PM domains and membranous organelles. Using an in situ extraction technique that preserves both microtubules and cellular membranes, we have developed a protocol for immunofluorescent co-localization of cytoskeletal elements and integral membrane proteins within 20 µm cryosections of fixed rat liver. Computer-aided 3D reconstruction of multi-spectral confocal microscope images was used to visualize the spatial relationships among the MT cytoskeleton, PM domains and intracellular organelles.

Evaluation of Structure-Controlled Silk Fibroin Coatings for Orthopedic Infection and In-Situ Osteogenesis: In Vitro and In Vivo

2020 ◽  
Author(s):  
Wenhao Zhou ◽  
Teng Zhang ◽  
Jianglong Yan ◽  
QiYao Li ◽  
Panpan Xiong ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Orthopedic Infection

scholarly journals Ferromagnetic soft catheter robots for minimally invasive bioprinting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cheng Zhou ◽  
Youzhou Yang ◽  
Jiaxin Wang ◽  
Qingyang Wu ◽  
Zhuozhi Gu ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
The Body ◽  
Magnetic Actuation ◽  
Internal Organs ◽  
Planar Surfaces ◽  
Reinforced Polymer ◽  
Direct Fabrication ◽  
Digitally Controlled

AbstractIn vivo bioprinting has recently emerged as a direct fabrication technique to create artificial tissues and medical devices on target sites within the body, enabling advanced clinical strategies. However, existing in vivo bioprinting methods are often limited to applications near the skin or require open surgery for printing on internal organs. Here, we report a ferromagnetic soft catheter robot (FSCR) system capable of in situ computer-controlled bioprinting in a minimally invasive manner based on magnetic actuation. The FSCR is designed by dispersing ferromagnetic particles in a fiber-reinforced polymer matrix. This design results in stable ink extrusion and allows for printing various materials with different rheological properties and functionalities. A superimposed magnetic field drives the FSCR to achieve digitally controlled printing with high accuracy. We demonstrate printing multiple patterns on planar surfaces, and considering the non-planar surface of natural organs, we then develop an in situ printing strategy for curved surfaces and demonstrate minimally invasive in vivo bioprinting of hydrogels in a rat model. Our catheter robot will permit intelligent and minimally invasive bio-fabrication.

scholarly journals Development of In Situ Self-Assembly Nanoparticles to Encapsulate Lopinavir and Ritonavir for Long-Acting Subcutaneous Injection

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 904
Author(s):  
Irin Tanaudommongkon ◽  
Asama Tanaudommongkon ◽  
Xiaowei Dong
Keyword(s):  
Sustained Release ◽  
Trough Concentration ◽  
Self Assembly ◽  
Subcutaneous Injection ◽  
Drug Loading ◽  
Entrapment Efficiency ◽  
Long Acting

Most antiretroviral medications for human immunodeficiency virus treatment and prevention require high levels of patient adherence, such that medications need to be administered daily without missing doses. Here, a long-acting subcutaneous injection of lopinavir (LPV) in combination with ritonavir (RTV) using in situ self-assembly nanoparticles (ISNPs) was developed to potentially overcome adherence barriers. The ISNP approach can improve the pharmacokinetic profiles of the drugs. The ISNPs were characterized in terms of particle size, drug entrapment efficiency, drug loading, in vitro release study, and in vivo pharmacokinetic study. LPV/RTV ISNPs were 167.8 nm in size, with a polydispersity index of less than 0.35. The entrapment efficiency was over 98% for both LPV and RTV, with drug loadings of 25% LPV and 6.3% RTV. A slow release rate of LPV was observed at about 20% on day 5, followed by a sustained release beyond 14 days. RTV released faster than LPV in the first 5 days and slower than LPV thereafter. LPV trough concentration remained above 160 ng/mL and RTV trough concentration was above 50 ng/mL after 6 days with one subcutaneous injection. Overall, the ISNP-based LPV/RTV injection showed sustained release profiles in both in vitro and in vivo studies.

Sign in / Sign up

Export Citation Format

Share Document