Objective To investigate the fluorescence resonance energy transfer (FRET) effect between dylight (DL) and AuNP (AuNP), and to construct a new fluorescence immunoassay for insulin in combination with the immunocompetition method. Methods Insulin antigen (Ag) and insulin antibody (Ab) were conjugated with DL and AuNP respectively to form DL-Ag conjugate and AUNp-AB conjugate. A novel fluorescence immunoassay for insulin was developed on the basis of FRET effect and the immune competition response between them. Then the performance of the method was evaluated and its application in actual samples was explored. Results The fluorescence immunoassay showed high sensitivity (0.015 ng/mL), short measurement time (4 min) and good specificity. It was successfully used in the measurement of serum insulin, and the recovery was between 96.9% and 121.1%. Conclusion FRET effect between AuNP and DL can be applied to develop a fluorescence immunoassay for the measurement of serum insulin.
Fluorescence Resonance Energy Transfer ; Insulin ; Immunoassay

Polymer micelles formed by self-assembly of amphiphilic polymers are widely used in drug delivery, gene delivery and biosensors, due to their special hydrophobic core/hydrophilic shell structure and nanoscale. However, the structural stability of polymer micelles can be affected strongly by environmental factors, such as temperature, pH, shear force in the blood and interaction with non-target cells, leading to degradations and drug leakage as drug carriers. Therefore, researches on the structural integrity and in vivo distribution of micelle-based carriers are very important for evaluating their therapeutic effect and clinical feasibility. At present, fluorescence resonance energy transfer (FRET) technology has been widely used in real-time monitoring of aggregation, dissociation and distribution of polymer micelles ( in vitro and in vivo). In this review, the polymer micelles, characteristics of FRET technology, structure and properties of the FRET-polymer micelles are briefly introduced. Then, methods and mechanism for combinations of several commonly used fluorescent probes into polymer micelles structures, and progresses on the stability and distribution studies of FRET-polymer micelles ( in vitro and in vivo) as drug carriers are reviewed, and current challenges of FRET technology and future directions are discussed.
Micelles ; Drug Carriers/chemistry* ; Polymers/chemistry* ; Fluorescence Resonance Energy Transfer ; Polyethylene Glycols/chemistry*

Objective: To obtain precise data on the changes in the levels of 29 cytokines in mice after high or low linear energy transfer (LET) irradiation and to develop an accurate model of radiation exposure based on the cytokine levels after irradiation. Methods: Plasma samples harvested from mice at different time points after carbon-ion or X-ray irradiation were analyzed using meso-scale discovery (MSD), a high-throughput and sensitive electrochemiluminescence measurement technique. Dose estimation equations were set up using multiple linear regression analysis. Results: The relative levels of IL-6 at 1 h, IL-5 and IL-6 at 24 h, and IL-5, IL-6 and IL-15 at 7 d after irradiation with two intensities increased dose-dependently. The minimum measured levels of IL-5, IL-6 and IL-15 were up to 4.0076 pg/mL, 16.4538 pg/mL and 0.4150 pg/mL, respectively. In addition, dose estimation models were established and verified. Conclusions The MSD assay can provide more accurate data regarding the changes in the levels of the cytokines IL-5, IL-6 and IL-15. These cytokines could meet the essential criteria for radiosensitive biomarkers and can be used as radiation indicators. Our prediction models can conveniently and accurately estimate the exposure dose in irradiated organism.
Animals ; Biological Assay ; Biomarkers/blood* ; Carbon ; Cytokines/blood* ; Female ; Heavy Ions ; Linear Energy Transfer ; Linear Models ; Mice ; Radiation Dosage ; Radiation, Ionizing

Fluorescent proteins can be used as probes to investigate intercellular molecular interactions and trace the pathway of specific metabolites, thus providing a detailed and accurate description of various metabolic processes and cellular pathways in living cells. Nowadays, the existing fluorescent proteins cover almost all spectral bands from ultraviolet to far-red. These fluorescent proteins have been applied in many fields of bioscience with the help of high-resolution microscopy, making great contributions to the development of biology. It is generally agreed that orange fluorescent proteins refer to the fluorescent proteins at the spectral range of 540-570 nm. In recent years, researches on orange fluorescent proteins have made great progress, and they have been widely applied in the field of biology and medicine as reporter protein and fluorescence resonance energy transfer as fluorescent receptor. This paper reviews the studies in the field of orange fluorescent proteins over the last 15 years, with the special focus on the development and application of orange fluorescent proteins to provide the basis for the future studies.
Biosensing Techniques ; trends ; Fluorescence Resonance Energy Transfer ; Luminescent Proteins ; metabolism ; Research ; trends

A combined cartilage holder and crusher is described that allows the surgeon to hold, crush, morselize, and suture a single piece or stack of cartilage graft without letting it slip. The customized slit-shaped jaws allow adequate room for the suture needle, while the serrated surfaces hold the cartilage firmly. The use of this instrument is advocated primarily in rhinoplasty for manipulating and suturing a small cartilage graft or a stack of grafts. The use of this instrument may be extended to aesthetic or reconstructive cases where cartilage grafts need to be sutured or shaped, as in eyelid, ear, and nipple reconstruction.
Cartilage ; Ear ; Eyelids ; Jaw ; Linear Energy Transfer ; Needles ; Nipples ; Rhinoplasty ; Sutures ; Transplants

The deoxyribonucleic acid (DNA) molecule damage simulations with an atom level geometric model use the traversal algorithm that has the disadvantages of quite time-consuming, slow convergence and high-performance computer requirement. Therefore, this work presents a density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm based on the spatial distributions of energy depositions and hydroxyl radicals (·OH). The algorithm with probability and statistics can quickly get the DNA strand break yields and help to study the variation pattern of the clustered DNA damage. Firstly, we simulated the transportation of protons and secondary particles through the nucleus, as well as the ionization and excitation of water molecules by using Geant4-DNA that is the Monte Carlo simulation toolkit for radiobiology, and got the distributions of energy depositions and hydroxyl radicals. Then we used the damage probability functions to get the spatial distribution dataset of DNA damage points in a simplified geometric model. The DBSCAN clustering algorithm based on damage points density was used to determine the single-strand break (SSB) yield and double-strand break (DSB) yield. Finally, we analyzed the DNA strand break yield variation trend with particle linear energy transfer (LET) and summarized the variation pattern of damage clusters. The simulation results show that the new algorithm has a faster simulation speed than the traversal algorithm and a good precision result. The simulation results have consistency when compared to other experiments and simulations. This work achieves more precise information on clustered DNA damage induced by proton radiation at the molecular level with high speed, so that it provides an essential and powerful research method for the study of radiation biological damage mechanism.
Algorithms ; Computer Simulation ; DNA ; radiation effects ; DNA Damage ; Linear Energy Transfer ; Monte Carlo Method ; Protons

Proteins are dynamic, fluctuating between multiple conformational states. Protein dynamics, spanning orders of magnitude in time and space, allow proteins to perform specific functions. Moreover, under certain conditions, proteins can morph into a different set of conformations. Thus, a complete understanding of protein structural dynamics can provide mechanistic insights into protein function. Here, we review the latest developments in methods used to determine protein ensemble structures and to characterize protein dynamics. Techniques including X-ray crystallography, cryogenic electron microscopy, and small angle scattering can provide structural information on specific conformational states or on the averaged shape of the protein, whereas techniques including nuclear magnetic resonance, fluorescence resonance energy transfer (FRET), and chemical cross-linking coupled with mass spectrometry provide information on the fluctuation of the distances between protein domains, residues, and atoms for the multiple conformational states of the protein. In particular, FRET measurements at the single-molecule level allow rapid resolution of protein conformational states, where information is otherwise obscured in bulk measurements. Taken together, the different techniques complement each other and their integrated use can offer a clear picture of protein structure and dynamics.
Fluorescence Resonance Energy Transfer ; Magnetic Resonance Spectroscopy ; Protein Conformation ; Proteins ; chemistry ; physiology

No abstract available.
Emergencies ; Humans ; Linear Energy Transfer

Neuropeptide oxytocin serves as a neuromodulator in the brain and as a hormone in the body. Oxytocin as a hypothalamic hormone causes contractions during the second and third stages of labor and lets milk come out during breast feeding. As a neuromodulator, oxytocin that influences social affiliative behavior plays an important role in social cognition and emotional learning. Recent studies showed that oxytocin affects basic fear learning and fear extinction precess in a social context. Furthermore, oxytocin has anxiolytic and stress-dampening effects when combined with social support, i.e. a safety stimuli. Also, oxytocin enhances basic emotional learning precesses of both acquisition and extinction of an emotional content while simultaneously decreasing pain experiences. Oxytocin has involvement in attachment, and is shown to improve positive affective behavior in romantic relations. Social buffering effects that social touch and emotional and physical intimacy play crucial roles in coping with negative effects are assumed to be mediated through brain oxytocin mechanisms. Researches indicate that oxytocin significantly inhibits hypothalamic-pituitary-adrenal axis activity in response to stress, and consequently reduces cortisol levels. Conversely, exposure to stress triggers the release of intrahypothalamic and plasma oxytocin. These results suggest that oxytocin may be a new pavement in treating post-traumatic stress disorder and depression.
Brain ; Breast Feeding ; Cognition ; Depression ; Hydrocortisone ; Learning ; Linear Energy Transfer ; Milk ; Neuropeptides ; Neurotransmitter Agents ; Oxytocin ; Plasma ; Stress Disorders, Post-Traumatic

BACKGROUND/OBJECTIVES: Exposure of the normal lung tissue around the cancerous tumor during radiotherapy causes serious side effects such as pneumonitis and pulmonary fibrosis. Radioprotectors used during cancer radiotherapy could protect the patient from side effects induced by radiation injury of the normal tissue. Delphinidin has strong antioxidant properties, and it works as the driving force of a radioprotective effect by scavenging radiation-induced reactive oxygen species (ROS). However, no studies have been conducted on the radioprotective effect of delphinidin against high linear energy transfer radiation. Therefore, this study was undertaken to evaluate the radioprotective effects of delphinidin on human lung cells against a proton beam. MATERIALS/METHODS: Normal human lung cells (HEL 299 cells) were used for in vitro experiments. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay assessed the cytotoxicity of delphinidin and cell viability. The expression of radiation induced cellular ROS was measured by the 2′-7′-dicholordihydrofluorescein diacetate assay. Superoxide dismutase activity assay and catalase activity assay were used for evaluating the activity of corresponding enzymes. In addition, radioprotective effects on DNA damage-induced cellular apoptosis were evaluated by Western blot assay. RESULTS: Experimental analysis, including cell survival assay, MTT assay, and Western blot assay, revealed the radioprotective effects of delphinidin. These include restoring the activities of antioxidant enzymes of damaged cells, increase in the levels of pro-survival protein, and decrease of pro-apoptosis proteins. The results from different experiments were compatible with each to provide a substantial conclusion. CONCLUSION: Low concentration (2.5 µM/mL) of delphinidin administration prior to radiation exposure was radioprotective against a low dose of proton beam exposure. Hence, delphinidin is a promising shielding agent against radiation, protecting the normal tissues around a cancerous tumor, which are unintentionally exposed to low doses of radiation during proton therapy.
Apoptosis ; Blotting, Western ; Catalase ; Cell Survival ; DNA ; Humans ; In Vitro Techniques ; Linear Energy Transfer ; Lung ; Pneumonia ; Proton Therapy ; Protons ; Pulmonary Fibrosis ; Radiation Exposure ; Radiation Injuries ; Radiotherapy ; Reactive Oxygen Species ; Superoxide Dismutase