Functional lumen imaging probe use in a high-volume practice:Practical and technical implications

BACKGROUND The functional lumen imaging probe(FLIP)is a Food and Drug Administration approved tool to aid the diagnosis and management of esophageal disorders.However,widespread adoption of FLIP remains limited and its utility in highvolume practices remains unclear.AIM To analyze large sample data on clinical use of FLIP and provide insight on several technical aspects when performing FLIP.METHODS We conducted a retrospective comparative and descriptive analysis of FLIP procedures performed by a single provider at an academic medical center.There was a total of 398 FLIP procedures identified.Patient medical records were reviewed and data regarding demographics and procedural details were collected.Statistical tests,including chi-squared,t-test,and multivariable logistic and linear regression,were performed.RESULTS There was an increase in FLIP cases with each successive time period of 13 months(n=68,146,184,respectively)with notable rises specifically for indications of dysphagia and gastroesophageal reflux disease.There was a shift toward use of the longer FLIP balloon catheter for diagnostic purposes(overall 70.4%vs 29.6%,P<0.01).Many cases(42.8%)were performed in conjunction with other diagnostics/interventions,such as dilation and wireless pH probe placement.Procedures were nearly equally performed with anesthesia vs moderate sedation(51.4%anesthesia),with no major complications.Patients who had anesthesia were less likely to have recurrent antegrade contractions[odds ratio(OR)=0.4,95%CI:0.3-0.8]and were also more likely to have absent contractility(OR=2.4,95%CI:1.3-CONCLUSION FLIP cases have increased in our practice with expanding indications for its use.Given limited normative data,providers should be aware of several potential technical issues,including the possible impact of sedation choice when assessing esophageal motility patterns.

Use of endolumenal functional lumen imaging probe in investigating paediatric gastrointestinal motility disorders

Investigating gastrointestinal(GI)motility disorders relies on diagnostic tools to assess muscular contractions,peristalsis propagation and the integrity and coordination of various sphincters.Manometries are the gold standard to study the GI motor function but it is increasingly acknowledged that manometries do not provide a complete picture in relation to sphincters competencies and muscle fibrosis.Endolumenal functional lumen imaging probe(EndoFLIP)an emerging technology,uses impedance planimetry to measure hollow organs cross sectional area,distensibility and compliance.It has been successfully used as a complementary tool in the assessment of the upper and lower oesophageal sphincters,oesophageal body,the pylorus and the anal canal.In this article,we aim to review the uses of EndoFLIP as a tool to investigate GI motility disorders with a special focus on paediatric practice.The majority of EndoFLIP studies were conducted in adult patients but the uptake of the technology in paediatrics is increasing.EndoFLIP can provide a useful complementary data to the existing GI motility investigation in both children and adults.

Engineering imaging probes and molecular machines for nanomedicine

Nanomedicine is an emerging field that integrates nanotechnology, biomolecular engineering, life sciences and medicine; it is expected to produce major breakthroughs in medical diagnostics and therapeutics. Due to the size-compatibility of nano-scale structures and devices with proteins and nucleic acids, the design, synthesis and application of nanoprobes, nanocarders and nanomachines provide unprecedented opportunities for achieving a better control of biological processes, and drastic im- provements in disease detection, therapy, and prevention. Recent advances in nanomedicine include the development of func- tional nanoparticle based molecular imaging probes, nano-structured materials as drug/gene carders for in vivo delivery, and engineered molecular machines for treating single-gene disorders. This review focuses on the development of molecular imag- ing probes and engineered nucleases for nanomedicine, including quantum dot bioconjugates, quantum dot-fluorescent protein FRET probes, molecular beacons, magnetic and gold nanoparticle based imaging contrast agents, and the design and validation of zinc finger nucleases （ZFNs） and TAL effector nucleases （TALENs） for gene targeting. The challenges in translating nano- medicine approaches to clinical applications are discussed.

ACTIVATABLE SMART PROBES FOR MOLECULAR OPTICAL IMAGING AND THERAPY

Recent years have seen the design and implementation of many optical activatable smart probes.These probes are activatable because they change their optical properties and are smart because they can identify specific targets.This broad class of detection agents has allowed previously unperformed visualizations,facilitating the study of diverse biomolecules including enzymes,nucleic acids,ions and reactive oxygen species.Designed to be robust in an in vivo environment,these probes have been used in tissue culture cells and in live small animals.An emerging class of smart probes has been designed to harness the potency of singlet oxygen generating photosensitizers.Combining the discrimination of activatable agents with the toxicity of photosensitizers represents a new and powerful approach to disease treatment.This review highlights some applications of activatable smart probes with a focus on developments of the past decade.

Light controlled imaging probes for intracellular target recognition： photochromism as a tool to enhance sensing precision

Chemosensors and imaging probes have been the focus of significant research interest over the past few decades. In part due to ease of preparation and simplicity in manipulation, fluorescent probes have been extensively used for biomedical applications. When used for #7 vitro cell imaging [1,2],

Imaging probes for non-invasive tumoral detection and functional monitoring of cancer multidrug resistance

Aim:Several cationic radiotracers originally developed as myocardial perfusion agents have shown potential for both early detection of cancer and non-invasive monitoring of multiple drug resistance(MDR)by single photon emission computed tomography.We have introduced two cationic complexes,^(99m)Tc-DMEOP[di-methoxy-tris-pyrazolyl-^(99m)Tc-(CO)_(3)]and ^(99m)Tc-TMEOP[tri-methoxy-tris-pyrazolyl-^(99m)Tc-(CO)_(3)],which showed excellent preclinical results as cardiac imaging probes,namely a persistent heart uptake with rapid blood and liver clearance.This study aimed at the evaluation of their usefulness for tumoral detection and functional assessment of MDR.Methods:The uptake and efflux kinetics of ^(99m)Tc-DMEOP and ^(99m)Tc-TMEOP were evaluated in human prostate,lung,and breast cancer cell lines,including drug-resistant cell lines that are known to overexpress the MDR P-glycoprotein(Pgp).The effects of MDR modulators were also studied.In vivo studies were performed in xenografted tumor models,and the MDR phenotype of the tumors was confirmed by Western blot.Results:The uptake kinetics of both complexes in human cancer cell lines is comparable with the one found for ^(99m)Tc-Sestamibi,increasing over time.The uptake of ^(99m)Tc-TMEOP is greatly reduced in cells overexpressing Pgp and increased in the presence of a Pgp modulator.In nude mice,the tumor uptake of ^(99m)Tc-TMEOP was higher in the MCF-7 xenografts compared with the MCF7 Pgp tumors.Conclusion:The uptake kinetics of both complexes in human cancer cell lines is comparable with the one found for ^(99m)Tc-Sestamibi,increasing over time.The uptake of ^(99m)Tc-TMEOP is greatly reduced in cells overexpressing Pgp,and increased in the presence of a Pgp modulator.In nude mice,the tumor uptake of ^(99m)Tc-TMEOP was higher in the MCF-7 xenografts compared with the MCF7 Pgp tumors.

Multimodal intravascular imaging technology for characterization of atherosclerosis

Early detection of vulnerable plaques is the critical step in the prevention of acute coronary events.Morphology,composition,and mechanical property of a coronary artery have been demonstrated to be the key characteristics for the identification of vulnerable plaques.Several intravascular multimodal imaging technologies providing co-registered simultaneous images have been developed and applied in clinical studies to improve the characterization of atherosclerosis.In this paper,the authors review the present system and probe designs of representative intra-vascular multimodal techniques.In addition,the scientific innovations,potential limitations,and future directions of these technologies are also discussed.

Assembly of a highly stable luminescent Zn5 cluster and application to bio-imaging

OBJECTIVE To explore a novel pH-sensitive fluorescent probe for in vivo tumor imaging.METHODS Zn5 were obtained in 140℃ after mixed with Me OH,water,Zn(NO_3)2·6 H_2O,H4L and trimethylamine.The fluorescence spectra of Zn5 with the same concentration in different pH aqueous solutions were detected.And the stability of Zn5 was investigated by time dependent fluorescence emission spectra of Zn5 in BSA aqueous solution and 5.0% serum solution.Then,the cytotoxicity of Zn5 was detected by MTT assays.To clarify whether a similar fluorescence response occurs in biological organisms,He La cells were pretreated with probe Zn5(0.5 μmol·L^(-1)) and fluorescence imaging were collected for targeting lysosomes in living cells because of lysosomes′ acidic microenvironment.The A375 tumor-bearing mice were used to assess the imaging ability of Zn5 in vivo.Mouse tumor xenografts were established by injection of A375 cells with 2×10~6 cells per flank.Probe(1 μg·g^(-1)) was administered to mice by injection.Images were obtained using IVIS Spectrum CT Imaging System.RESULTS There is a 11-fold intensity increasing as the pH values changing from 8 to 2.The almost unchanged emission intensities suggest Zn5 is stable in both BSA and serum.Zn5 has negligible cytotoxicity for He La,293 T and CHO-K1 cells.Zn5 can selectively display lysosomes in living cells.Both the 2D and 3D images in vivo distinguish the tumor from other tissues with good fluorescence contrast.CONCLUSION The high chemical stability,emission in the Vis/NIR range,pH sensitivity,a pKa located in the tumor pH range,and low toxicity make Zn5 is suitable for application as a pH-sensitive fluorescent probe for bio-imaging.

Molecular imaging:design mechanism and bioapplications

Molecular imaging is a non-invasive method to image and analyze the concentration and activity of functional biomolecules in cells or in vivo at molecular level,and plays an increasing role in deep understanding of biological processes,early and accurate diagnosis of diseases,and evaluation of treatment.Nowadays,numerous novel molecular imaging probes have been developed,involving every biomedical imaging modality,such as optical imaging,photoacoustic imaging,magnetic resonance imaging,single-photon-emission computed tomography,and positron emission tomography.In this review,we summarize the development of current state-of-the-art molecular imaging probes.We introduce the design strategies of molecular probes and detailed imaging modalities,and highlight the properties of probes and biomedical imaging applications in cells and in vivo,including disease diagnosis,drug tracking,and imaging-guided surgery.Then we discuss the perspectives and challenges in this emerging field.We expect this review could inspire more effective molecular imaging probes to be developed,achieving the goal towards clinical practices.

磁共振钆靶向对比剂的研究现状及展望

特异性MR靶向对比剂通过与体内特定的靶点结合显示活体分子靶点状态,为临床提供分子水平的信息。选择针对特定靶点的特异性运载体和良好的MR显像剂,是构建良好分子探针的一个关键因素。钆剂作为临床常用的MR对比剂,在构建分子探针上具有诸多优势,目前在MR分子成像领域进行了大量实验研究。就目前研究常用的分子靶点和分子探针,对MR钆靶向对比剂的研究现状及展望进行综述。

A bestatin-based fluorescent probe for aminopeptidase N cell imaging

Aminopeptidase N （APN） is an important drug target and biomarker for various tumors. The current work characterizes a novel APN-targeted fluorescent probe （Bes-Green, 2） that manifests comparable inhibitory activity with Bestatin. This probe has capacity of tightly binding to the APN for imaging endogenous APN in living human ovarian clear cell carcinoma cells （ES-2） and has potential application in biological study of cellular APN.

AIEgen based light-up probes for live cell imaging

Fluorescent light-up probes comprising a tetraphenylethene unit with aggregation-induced emission(AIE)characteristics and a water-soluble peptide have been designed and synthesized which provide cell membrane and nuclear permeability to live cells.This strategy has offered new opportunities for the development of probes with light-up ability and good signal-to-noise ratio.The selectivity or targeting specificity is determined by the peptide sequence,i.e.a nuclear localization signal that leads to nucleus imaging and a cell biomarker targeting peptide that offers specific light-up imaging of HT-29 cells.

Molecular imaging of enzyme activity in vivo using activatable probes

Precise measurement of enzyme activity in living systems with molecular imaging probes is becoming an important technique to unravel the functional roles of different enzymes in biological processes. Recent progress has been made in the development of a myriad of molecular imaging probes featuring different imaging modalities, including optical imaging, magnetic resonance imaging, nuclear imaging, and photoacoustic imaging, allowing for non-invasive detection of various enzyme activities in vivo with high sensitivity and high spatial resolution. Among these imaging probes, activatable or ＂smart＂ probes, whose imaging signal can be specifically switched from the ＂off＂ to ＂on＂ state upon interaction with a target enzyme, are particularly attractive due to their improved sensitivity and specificity. Here, recent advances in the development of activatable probes capable of imaging different enzyme activities in vivo are summarized based on different imaging modalities, and current challenges and future perspectives are discussed.

Ratiometric and selective two-photon fluorescent probe based on PET-ICT for imaging Zn^(2+)in living cells and tissues

A two-photon fluorescent probe TPZn was developed for specific ratiometric imaging Zn2＋ in living cells and tissues. Significant ratiometric fluorescence change was based on photoinduced electron transfer and intramolecular charge transfer. The synthetic method of TPZn was simple. It was successfully used to selectively image Zn2＋ based on the higher binding affinity for Zn2＋ than for Cd2＋. TPZn was easily loaded into the living cell and tissues with high membrane permeability in a complex biological environment. TPZn could clearly visualize endogenous Zn2＋ by TP ratiometric imaging in hippocampal slices at a depth of 120 μm. Thus, TPZn is a useful tool to image of Zn2＋ in living cells and tissues without interference from Cd2＋.

Highly selective two-photon fluorescent probe for imaging of nitric oxide in living cells

A new two-photon fluorescent probe, ADNO, for nitric oxide （NO） based on intramolecular photoinduced electron transfer （PET） mechanism d/splays a rapid response to NO with a remarkable fluorescent enhancement in PBS buffer. The excellent chemoselectivity of ADNO for NO over other ROS/RNS （reactive oxygen species or nitrogen species） and common metal ions was observed. Moreover, ADNO has been successfully applied in fluorescence imaging of NO of living cells using both one-photon microscopy （OPM） and two-~hoton microscopy （TPM）,

Microball lens integrated fiber probe for optical frequency domain imaging

An integrated microball lens fiber catheter probe is demonstrated, which has better lateral resolution and longer working distance than a corresponding bare fiber probe with diverging beam for Fourier domain optical coherence tomography （FDOCT）. Simulation results are shown to gain the effect of the distance between the mieroball lens and the bare fiber to the focusing plane and beam width. The freedom of modifying the working distance and lateral resolution is shown. This is achieved by changing the gap distance between the single-mode fiber and the microball lens within the packaged surgical needle catheter without using an additional beam expander having a fixed length. The probe successfully acquired crosssectional images of ocular tissues from an animal sample with the proposed miniaturized imaging probe.

A 1,8-naphthalimide-derived turn-on fluorescent probe for imaging lysosomal nitric oxide in living cells

Nitric oxide has played an important role in many physiological and pathological processes as a kind of important gas signal molecules. In this work, a new fluorescent probe LysoNO-Naph for detecting NO in lysosomes based on 1,8-naphthalimide was reported. LysoNO-Naph has sub-groups of o-phenylene- diamine as a NO reaction site and 4-（2-aminoethyl）-morpholine as a lysosome-targetable group. This probe exhibited good selectivity and high sensitivity （4.57 μmol/L） toward NO in a wide pH range from 4 to 12. Furthermore, LysoNO-Naph can be used for imaging NO in lysosomes in living cells.

Biomarker-targeted fluorescent probes for breast cancer imaging

Breast cancer has become a common tumor worldwide which seriously endangers people＇s health. Earlydiagnosis and treatment are particularly urgent in order to reduce the onset risk, mortality, and prolongthe five-year survival rate. Therefore, we need a kind of diagnosis and treatment technology with highspecificity, sensitivity and selectivity. In recent years, because of its unique properties in biologicalapplications, fluorescence imaging has become an attractive research subject. Fluorescence imagingoffers innovative ideas of targetable recognition of breast cancer cells, breast cancer imaging in vivoanimal models, anticancer drugs delivery for guiding the mammary surgery via a noninvasive way withhigh sensitively and specifically. In this review, we summarized the recent advances of fluorescent probesfor breast cancer imaging, which were classified according to different biomarkers the probes recognized.Moreover, we discussed the strengths, built-in problems as well as the challenges about the fluorescentprobe as a unique potential method for the better application in breast cancer diagnosis and treatment.~ 2018 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

A pH-Activatable Fluorescent Aptamer Probe for Imaging of Target Cancer Cells

Early cancer diagnosis in molecular level shows great promise in relevant prevention and clinical treatment. Herein, we developed a novel method to detect and evaluate biomarkers on cancer cell surface. Based on the excellent selectivity of AS1411 aptamer to targeted nucleolin-overexpressed cells, we used a fluorescent probe with a pH-sensitive function to label the AS1411 aptamer modified with azide by click-reaction. The spectral characteristics of fluorophore naphthalimide has a good pH dependence. By this way, nucleolin-overexpressed cell could be discriminated from normal cell. Further, this strategy could also discriminate the breast cancer tissue from the adjacent benign tissue in formalin-fixed and parrffin-embedded（FFPE） tissue specimens. It is considered that our method has the potential to be applied in medical detection.

A novel nitroreductase-enhanced MRI contrast agent and its potential application in bacterial imaging

Nitroreductases(NTRs) are known to be able to metabolize nitro-substituted compounds in the presence of reduced nicotinamide adenine dinucleotide(NADH) as an electron donor. NTRs are present in a wide range of bacterial genera and, to a lesser extent, in eukaryotes hypoxic tumour cells and tumorous tissues, which makes it an appropriate biomarker for an imaging target to detect the hypoxic status of cancer cells and potential bacterial infections. To evaluate the specific activation level of NTR, great efforts have been devoted to the development of fluorescent probes to detect NTR activities using fluorogenic methods to probe its behaviour in a cellular context; however, NTR-responsive MRI contrast agents are still by far underexplored. In this study, para-nitrobenzyl substituted T_1-weighted magnetic resonance imaging(MRI)contrast agent Gd-DOTA-PNB(probe 1) has been designed and explored for the possible detection of NTR.Our experimental results show that probe 1 could serve as an MRI-enhanced contrast agent for monitoring NTR activity. The in vitro response and mechanism of the NTR catalysed reduction of probe 1 have been investigated through LC–MS and MRI. Para-nitrobenzyl substituted probe 1 was catalytically reduced by NTR to the intermediate para-aminobenzyl substituted probe which then underwent a rearrangement elimination reaction to Gd-DOTA, generating the enhanced T1-weighted MR imaging. Further, LC–MS and MRI studies of living Escherichia coli have confirmed the NTR activity detection ability of probe 1 at a cellular level. This method may potentially be used for the diagnosis of bacterial infections.