Reflectance and fluorescent contrast agents for real-time in vivo confocal imaging

2000 ◽  
Author(s):  
Milind Rajadhyaksha ◽  
Mark Henrichs ◽  
K. P. Ananth ◽  
Hung-Ta Chang ◽  
Salvador González
Keyword(s):  
Contrast Agents ◽  
Real Time ◽  
Confocal Imaging

scholarly journals Precise closure of single blood vessels via multiphoton absorption–based photothermolysis

2019 ◽  
Vol 5 (5) ◽  
pp. eaan9388 ◽  
Author(s):  
Yimei Huang ◽  
Zhenguo Wu ◽  
Harvey Lui ◽  
Jianhua Zhao ◽  
Shusen Xie ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Real Time ◽  
Vascular Diseases ◽  
Confocal Imaging ◽  
Multiphoton Absorption ◽  
Vessel Occlusion ◽  
Novel Approach ◽  
Vessel Closure ◽  
Stroke Models

We report a novel approach to selectively close single blood vessels within tissue using multiphoton absorption–based photothermolysis (multiphoton photothermolysis) without the need of exogenous agents. The treatment process is monitored by in vivo reflectance confocal microscopy in real time. Closure of single targeted vessels of varying sizes ranging from capillaries to venules was demonstrated. We also demonstrated that deeply situated blood vessels could be closed precisely while preserving adjacent overlying superficial blood vessels. In vivo confocal Raman spectroscopy of the treatment sites confirmed vessel closure as being mediated by local coagulative damage. Partial vessel occlusion could be achieved, and it is accompanied by increased intravascular blood cell speed. Multiphoton photothermolysis under real-time reflectance confocal imaging guidance provides a novel precision medicine approach for noninvasive, precise microsurgery treatment of vascular diseases on a per-vessel/per-lesion basis. The method could also be used for building ischemic stroke models for basic biology study.

Confocal Laser Endomicroscopy: A Primer for Pathologists

2011 ◽  
Vol 135 (10) ◽  
pp. 1343-1348 ◽  
Author(s):  
Peter E Paull ◽  
Benjamin J Hyatt ◽  
Wahid Wassef ◽  
Andrew H Fischer
Keyword(s):  
Contrast Agents ◽  
Paraffin Section ◽  
Improve Patient Care ◽  
Molecular Classification ◽  
Confocal Imaging ◽  
Confocal Laser Endomicroscopy ◽  
Confocal Laser ◽  
Diagnostic Features ◽  
Immunohistochemical Studies

Context.—The advent of new endoscopic optical techniques is likely to change pathologists' role in diagnosis. Objective.—To describe how confocal laser endomicroscopy (CLE) works, show its advantages and limitations compared to cytohistologic biopsy, and explore how it may affect the practice of pathology. Data Sources.—Literature review. Conclusions.—Confocal laser endomicroscopy is proving its ability to provide histology-like images of tissues in vivo to help avoid risks and costs of conventional biopsies. Confocal imaging restricts light to 1 plane, emulating a paraffin section, and topical or systemic optical contrast agents allow subcellular resolution. New contrast agents could theoretically permit molecular characterization. In vivo imaging has begun to demonstrate novel, dynamic types of diagnostic features. Decreased histologic biopsies can be anticipated for a few scenarios. Significant limitations of CLE include the inability to create a tissue archive for broad molecular classification, suboptimal contrast agents, small fields of view and shallow penetration, paucity of clinical validation studies, and problems with reimbursement. Confocal laser endomicroscopy exposes new opportunities for pathologists: CLE technologies can be exploited in pathology, and diagnostic criteria expanded based on endoscopists' discoveries. Potential synergy exists between CLE and cytology, allowing the low-magnification diagnostic architectural changes by CLE and cytomorphology to emulate the full diagnostic information in a histologic biopsy while providing an archive of material for molecular or immunohistochemical studies. Confocal laser endomicroscopy will decrease some types of biopsies, but offers an opportunity for pathologists to find new ways to provide value and improve patient care.

scholarly journals Modeling Immune Checkpoint Inhibitor Efficacy in Syngeneic Mouse Tumors in an Ex Vivo Immuno-Oncology Dynamic Environment

2020 ◽  
Vol 21 (18) ◽  
pp. 6478
Author(s):  
Daniel T. Doty ◽  
Julia Schueler ◽  
Vienna L. Mott ◽  
Cassie M. Bryan ◽  
Nathan F. Moore ◽  
...  
Keyword(s):  
Real Time ◽  
Mouse Models ◽  
Immune Checkpoint ◽  
Checkpoint Inhibitors ◽  
Ex Vivo ◽  
Confocal Imaging ◽  
Checkpoint Blockade ◽  
Syngeneic Mouse

The immune checkpoint blockade represents a revolution in cancer therapy, with the potential to increase survival for many patients for whom current treatments are not effective. However, response rates to current immune checkpoint inhibitors vary widely between patients and different types of cancer, and the mechanisms underlying these varied responses are poorly understood. Insights into the antitumor activities of checkpoint inhibitors are often obtained using syngeneic mouse models, which provide an in vivo preclinical basis for predicting efficacy in human clinical trials. Efforts to establish in vitro syngeneic mouse equivalents, which could increase throughput and permit real-time evaluation of lymphocyte infiltration and tumor killing, have been hampered by difficulties in recapitulating the tumor microenvironment in laboratory systems. Here, we describe a multiplex in vitro system that overcomes many of the deficiencies seen in current static histocultures, which we applied to the evaluation of checkpoint blockade in tumors derived from syngeneic mouse models. Our system enables both precision-controlled perfusion across biopsied tumor fragments and the introduction of checkpoint-inhibited tumor-infiltrating lymphocytes in a single experiment. Through real-time high-resolution confocal imaging and analytics, we demonstrated excellent correlations between in vivo syngeneic mouse and in vitro tumor biopsy responses to checkpoint inhibitors, suggesting the use of this platform for higher throughput evaluation of checkpoint efficacy as a tool for drug development.

scholarly journals New generation of magnetic and luminescent nanoparticles for in vivo real-time imaging

2013 ◽  
Vol 3 (3) ◽  
pp. 20120103 ◽  
Author(s):  
Lise-Marie Lacroix ◽  
Fabien Delpech ◽  
Céline Nayral ◽  
Sébastien Lachaize ◽  
Bruno Chaudret
Keyword(s):  
Contrast Agents ◽  
Real Time ◽  
Metallic Nanoparticles ◽  
Surface Engineering ◽  
Semiconductor Nanocrystals ◽  
Fluorescent Imaging ◽  
Real Time Imaging ◽  
Specific Targeting ◽  
New Generation

A new generation of optimized contrast agents is emerging, based on metallic nanoparticles (NPs) and semiconductor nanocrystals for, respectively, magnetic resonance imaging (MRI) and near-infrared (NIR) fluorescent imaging techniques. Compared with established contrast agents, such as iron oxide NPs or organic dyes, these NPs benefit from several advantages: their magnetic and optical properties can be tuned through size, shape and composition engineering, their efficiency can exceed by several orders of magnitude that of contrast agents clinically used, their surface can be modified to incorporate specific targeting agents and antifolding polymers to increase blood circulation time and tumour recognition, and they can possibly be integrated in complex architecture to yield multi-modal imaging agents. In this review, we will report the materials of choice based on the understanding of the basic physics of NIR and MRI techniques and their corresponding syntheses as NPs. Surface engineering, water transfer and specific targeting will be highlighted prior to their first use for in vivo real-time imaging. Highly efficient NPs that are safer and target specific are likely to enter clinical application in a near future.

scholarly journals Real-time Ratiometric Imaging of Micelles Assembly State in a Microfluidic Cancer-on-a-chip

2020 ◽  
Author(s):  
Natalia Feiner-Gracia ◽  
Adrianna Glinkowska Mares ◽  
Marina Buzhor ◽  
Romen Rodriguez-Trujillo ◽  
Josep Samitier ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Real Time ◽  
Rational Design ◽  
Confocal Imaging ◽  
Fluorescent Properties ◽  
Key Factor ◽  
Low Efficiency

ABSTRACTThe performance of supramolecular nanocarriers as drug delivery systems depends on their stability in the complex and dynamic biological media. After administration, nanocarriers are challenged by confronting different barriers such as shear stress and proteins present in blood, endothelial wall, extracellular matrix and eventually cancer cell membranes. While early disassembly will result in a premature drug release, extreme stability of the nanocarriers can lead to poor drug release and low efficiency. Therefore, comprehensive understanding of the stability and assembly state of supramolecular carriers in each stage of delivery is a key factor for the rational design of these systems. One of the key challenges is that current 2D in vitro models do not provide exhaustive information, as they do not fully recapitulate the 3D tumor microenvironment. This deficiency of the 2D models complexity is the main reason for the differences observed in vivo when testing the performance of supramolecular nanocarriers. Herein, we present a real-time monitoring study of self-assembled micelles stability and extravasation, combining spectral confocal microscopy and a microfluidic tumor-on-a-chip. The combination of advanced imaging and a reliable organ-on-a-chip model allow us to track micelle disassembly by following the spectral properties of the amphiphiles in space and time during the crucial steps of drug delivery. The spectrally active micelles were introduced under flow and their position and conformation followed during the crossing of barriers by spectral imaging, revealing the interplay between carrier structure, micellar stability and extravasation. Integrating the ability of the micelles to change their fluorescent properties when disassembled, spectral confocal imaging and 3D microfluidic tumor blood vessel-on-a-chip, resulted in the establishment of a robust testing platform, suitable for real-time imaging and evaluation of supramolecular drug delivery carrier’s stability.

Real-time confocal microscopy of the human in vivo cornea

1993 ◽  
Vol 51 ◽  
pp. 166-167
Author(s):  
Barry R. Masters ◽  
Andreas A. Thaer
Keyword(s):  
Real Time ◽  
Detection System ◽  
Water Immersion ◽  
Video Recording ◽  
Video Camera ◽  
Confocal Imaging ◽  
Infrared Light ◽  
Halogen Lamp ◽  
Video Monitor

A new confocal microscope has several unique features which differentiates it from other in vivo confocal imaging systems.is described. • The light source is a halogen lamp. This source has many advantages over the mercury or xenon arc lamps used in other confocal designs. The mercury or xenon arc lamps have the problem of arc jitter which results in changing illumination intensity. Filters are inserted in the lamp housing to remove both short ultraviolet and infrared light. • The microscope uses standard microscope objectives which are readily interchangeable. Other in vivo confocal systems are limited to a built in objective which is not removable. In these studies we used a Leitz 50X, NA 1.0 water immersion objective.• The detection system consists of an intensitified video camera with video output to a Sony U-matic tape recorder. In parallel with the video recording there is a video monitor in order that the operator can observe in real-time the confocal images of the subject's eye.

Abstract 5960: Implementation of Noninvasive Subharmonic Pressure Estimation on a Commercial Ultrasound Scanner

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Lauren M Leodore ◽  
Corina Leung ◽  
Laurent Pelissier ◽  
Flemming Forsberg
Keyword(s):  
Contrast Agents ◽  
Real Time ◽  
Pressure Range ◽  
Linear Regression Analysis ◽  
Heart Association ◽  
Center Frequency ◽  
Single Element ◽  
Pressure Estimation

This project aims to monitor and quantify intra-cardiac pressures via contrast-enhanced subharmonic imaging. We have proposed subharmonic aided pressure estimation (SHAPE; U.S. Patent 6,302,845) utilizing microbubble-based contrast agent signals for the noninvasive estimation of hydrostatic blood pressures in the heart cavities and in this study implemented real-time SHAPE on a commercial US scanner. An experimental pulse-echo system for SHAPE was constructed based on two single element transducers assembled confocally at a 60° angle to each other. A transducer with a bandwidth of 38% and a center frequency of 2.2 MHz (Staveley, East Hartford, CT) was used as the transmitter and a second transducer with a bandwidth of 86% and a center frequency of 3.6 MHz (Etalon Inc., Lebanon, IN) was the receiver. Changes in first, second, and subharmonic amplitudes of 6 different US contrast agents were measured in vitro at hydrostatic pressures from 0 –186 mmHg, acoustic pressures from 0.35– 0.60 MPa and frequencies of 2.5– 6.6 MHz. The optimal parameters for SHAPE were determined using linear regression analysis and implemented on a Sonix RP scanner (Ultrasonix Medical Corp, Richmond, Canada). The real-time implementation of SHAPE was tested in vitro. Over the pressure range studied the 1st and 2nd harmonic amplitudes reduced ~2 dB for all US contrast agents. Over the same pressure range, the subharmonic amplitudes decreased by 10 –14 dB and excellent linear regressions were achieved with the hydrostatic pressure variations (r 2 >0.98, p < 0.001). The optimal sensitivity for SHAPE was achieved at a transmit frequency of 2.5 MHz (i.e., receiving at 1.25 MHz) at a 0.35 MPa acoustic pressure using Sonazoid (GE Healthcare, Oslo, Norway) which declined ~14.4 dB in vitro. A Sonix RP scanner was modified to implement SHAPE on a phased array transducer PA4 –2 with a frequency range from 1.5– 4.5 MHz. A pulse inversion technique was used and the subharmonic signals are displayed in real-time and can also be stored for off-line analysis. SHAPE offers the possibility of allowing pressure gradients in the heart to be obtained noninvasively. Future studies will include in vivo pressure measurements. Supported by AHA grant no 06554414 and NIH HL081892. This research has received full or partial funding support from the American Heart Association, AHA Great Rivers Affiliate (Delaware, Kentucky, Ohio, Pennsylvania & West Virginia).

scholarly journals Real-Time In Vivo Imaging of Mouse Left Ventricle Reveals Fluctuating Movements of the Intercalated Discs

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 532
Author(s):  
Fuyu Kobirumaki-Shimozawa ◽  
Tomohiro Nakanishi ◽  
Togo Shimozawa ◽  
Takako Terui ◽  
Kotaro Oyama ◽  
...  
Keyword(s):  
Real Time ◽  
Connexin 43 ◽  
Myocardial Contraction ◽  
Confocal Imaging ◽  
Electronic Conduction ◽  
Mouse Heart ◽  
Living Mouse ◽  
Small Change ◽  
Cardiac Sodium Channels

Myocardial contraction is initiated by action potential propagation through the conduction system of the heart. It has been thought that connexin 43 in the gap junctions (GJ) within the intercalated disc (ID) provides direct electric connectivity between cardiomyocytes (electronic conduction). However, recent studies challenge this view by providing evidence that the mechanosensitive cardiac sodium channels Nav1.5 localized in perinexii at the GJ edge play an important role in spreading action potentials between neighboring cells (ephaptic conduction). In the present study, we performed real-time confocal imaging of the CellMask-stained ID in the living mouse heart in vivo. We found that the ID structure was not rigid. Instead, we observed marked flexing of the ID during propagation of contraction from cell to cell. The variation in ID length was between ~30 and ~42 μm (i.e., magnitude of change, ~30%). In contrast, tracking of α-actinin-AcGFP revealed a comparatively small change in the lateral dimension of the transitional junction near the ID (i.e., magnitude of change, ~20%). The present findings suggest that, when the heart is at work, mechanostress across the perinexii may activate Nav1.5 by promoting ephaptic conduction in coordination with electronic conduction, and, thereby, efficiently transmitting excitation-contraction coupling between cardiomyocytes.

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