Ablation of Transcription Factor IRF4 Promotes Transplant Acceptance by Driving Allogenic CD4+ T Cell Dysfunction.

CD4+ T cells orchestrate immune responses and destruction of allogeneic organ transplants, but how this process is regulated on a transcriptional level remains unclear. Here, we demonstrated that interferon regulatory factor 4 (IRF4) was a key transcriptional determinant controlling T cell responses during transplantation. IRF4 deletion in mice resulted in progressive establishment of CD4+ T cell dysfunction and long-term allograft survival. Mechanistically, IRF4 repressed PD-1, Helios, and other molecules associated with T cell dysfunction. In the absence of IRF4, chromatin accessibility and binding of Helios at PD-1 cis-regulatory elements were increased, resulting in enhanced PD-1 expression and CD4+ T cell dysfunction. The dysfunctional state of Irf4-deficient T cells was initially reversible by PD-1 ligand blockade, but it progressively developed into an irreversible state. Hence, IRF4 controls a core regulatory circuit of CD4+ T cell dysfunction, and targeting IRF4 represents a potential therapeutic strategy for achieving transplant acceptance.

The Costimulatory Receptor OX40 Inhibits Interleukin-17 Expression through Activation of Repressive Chromatin Remodeling Pathways.

T helper 17 (Th17) cells are prominently featured in multiple autoimmune diseases, but the regulatory mechanisms that control Th17 cell responses are poorly defined. Here we found that stimulation of OX40 triggered a robust chromatin remodeling response and produced a "closed" chromatin structure at interleukin-17 (IL-17) locus to inhibit Th17 cell function. OX40 activated the NF-κB family member RelB, and RelB recruited the histone methyltransferases G9a and SETDB1 to the Il17 locus to deposit "repressive" chromatin marks at H3K9 sites, and consequently repressing IL-17 expression. Unlike its transcriptional activities, RelB acted independently of both p52 and p50 in the suppression of IL-17. In an experimental autoimmune encephalomyelitis (EAE) disease model, we found that OX40 stimulation inhibited IL-17 and reduced EAE. Conversely, RelB-deficient CD4(+) T cells showed enhanced IL-17 induction and exacerbated the disease. Our data uncover a mechanism in the control of Th17 cells that might have important clinic implications.

Role of sestrins in metabolic and aging-related diseases.

Sestrins are a type of highly conserved stress-inducing protein that has antioxidant and mTORC1 inhibitory functions. Metabolic dysfunction and aging are the main risk factors for development of human diseases, such as diabetes, neurodegenerative diseases, and cancer. Sestrins have important roles in regulating glucose and lipid metabolism, anti-tumor functions, and aging by inhibiting the reactive oxygen species and mechanistic target of rapamycin complex 1 pathways. In this review, the structure and biological functions of sestrins are summarized, and how sestrins are activated and contribute to regulation of the downstream signal pathways of metabolic and aging-related diseases are discussed in detail with the goal of providing new ideas and therapeutic targets for the treatment of related diseases.

Acute Pancreatitis in Pregnancy: A Propensity Score Matching Analysis and Dynamic Nomogram for Risk Assessment.

BACKGROUND: Acute pancreatitis is easily confused with abdominal pain symptoms, and it could lead to serious complications for pregnant women and fetus, the mortality was as high as 3.3% and 11.6-18.7%, respectively. However, there is still lack of sensitive laboratory markers for early diagnosis of APIP and authoritative guidelines to guide treatment. OBJECTIVE: The purpose of this study was to explore the risk factors of acute pancreatitis in pregnancy, establish, and evaluate the dynamic prediction model of risk factors in acute pancreatitis in pregnancy patients. STUDY DESIGN: Clinical data of APIP patients and non-pregnant acute pancreases patients who underwent regular antenatal check-ups during the same period were collected. The dataset after propensity matching was randomly divided into training set and verification set at a ratio of 7:3. The model was constructed using Logistic regression, least absolute shrinkage and selection operator regression, R language and other methods. The training set model was used to construct the diagnostic nomogram model and the validation set was used to validate the model. Finally, the accuracy and clinical practicability of the model were evaluated. RESULTS: A total of 111 APIP were included. In all APIP patients, hyperlipidemic pancreatitis was the most important reason. The levels of serum amylase, creatinine, albumin, triglyceride, high-density lipoprotein cholesterol, and apolipoprotein A1 were significantly different between the two groups. The propensity matching method was used to match pregnant pancreatitis patients and pregnant non-pancreatic patients 1:1 according to age and gestational age, and the matching tolerance was 0.02. The multivariate logistic regression analysis of training set showed that diabetes, triglyceride, Body Mass Index, white blood cell, and C-reactive protein were identified and entered the dynamic nomogram. The area under the ROC curve of the training set was 0.942 and in validation set was 0.842. The calibration curve showed good predictive in training set, and the calibration performance in the validation set was acceptable. The calibration curve showed the consistency between the nomogram model and the actual probability. CONCLUSION: The dynamic nomogram model we constructed to predict the risk factors of acute pancreatitis in pregnancy has high accuracy, discrimination, and clinical practicability.

Performance Evaluation of Newly-Developed Tumor Markers Assay Kit Based on Flow Fluorescence Assay.

BACKGROUND: The purpose of this study is to evaluate the performance of recently developed tumor marker clinical kits in China, with the aim of encouraging local medical technology innovation and thus narrowing the research and development gap with foreign kits. METHODS: The newly established reagent kits were analyzed on the TESMI F3999-Luminex200 flow lattice instrument to verify precision, sensitivity (blank limit), linearity, anti-interference ability, carry-over contamination rate, hook effect, and reference interval verification. Additionally, the newly established reagent kits were compared to other commercially available detection kits (reference reagent kits) to analyze the correlation between the two types of kits. RESULTS: The intra-assay and inter-assay precision had coefficients of variations (CVs) less than 3.50% and 6.91%, respectively. The tumor marker blank limits were lower than the manufacturer's statement. The newly established reagent kits demonstrated excellent linearity (r > 0.99). Rheumatoid factor, triglycerides, bilirubin, and hemoglobin did not have significant interference with the determination of tumor markers. The carry-over contamination rates were all much lower than 3%. At extremely high concentrations of AFP (277,335 ng/mL and 1,031,424 ng/mL), the measured tumor marker values were higher than the upper limit of the linear range and no hook effect occurred. The reference interval was suitable for use in clinical laboratory settings. Correlation analysis indicated a satisfactory relevance and consistency between the newly developed reagent kits and reference reagent kits, with correlation coefficients of r > 0.967 among 654 patients and healthy individuals. CONCLUSIONS: The newly developed reagent kits for tumor markers performed well in all evaluated parameters, having the potential for clinical promotion and application.

Partial molecular characterization, expression pattern and polymorphism analysis of MHC I genes in Chinese domestic goose (Anser cygnoides).

Major histocompatibility complex (MHC) allelic polymorphism is critically important for mediating antigen presentation in vertebrates. Presently, there are insufficient studies of MHC genetic diversity in domestic Anseriform birds. In this study, we analyzed the expression profile of MHC I genes and screened for MHC I exon 2 polymorphism in one domestic goose population from China using Illumina MiSeq sequencing. The results showed that four MHC I alleles (Ancy-IE2*09/*11/*13/*21) in one goose were identified based on cDNA cloning and sequencing using four primer combinations, and the varying number of cDNA clones implied that these four classical sequences showed differential expression patterns. Through next-generation sequencing, 27 alleles were obtained from 68 geese with 3-10 putative alleles per individual, indicating at least the existence of 5 MHC I loci in the goose. The marked excess of the non-synonymous over the synonymous substitution in the peptide-binding region (PBR) along 27 alleles and five positively selected sites (PSSs) detected around the PBR indicated that balancing selection might be the major force in shaping high MHC variation in the goose. Additionally, IA alleles displaying lower polymorphism were subject to less positive selection pressure than non-IA alleles with a higher level of polymorphism.

Gender differences of authors of major Hepatology society guidelines during the past 15 years.

BACKGROUND AND OBJECTIVE: Recent studies have shown that women are underrepresented as authors of medical research and clinical practice guidelines. This study aimed to evaluate gender disparities of authors of major hepatology guidelines. METHODS: We reviewed the hepatology guidelines published by the following major gastroenterology societies from January 2008 to September 2022: the American Gastroenterological Association (AGA), American College of Gastroenterology (ACG), American Association for the Study of Liver Diseases (AASLD), Asian-Pacific Association for the Study of the Liver (APASL), British Society of Gastroenterology (BSG), European Association for the Study of the Liver (EASL) and Korean Association for the Study of the Liver (KASL). We determined the topic and the gender of all authors of each guideline. The numbers of men authors, women authors and total authors were collected. The trends of women first authors, women senior authors and total women authors were assessed. A logistic regression analysis was performed to analyse the relationship between the gender of the first or senior author and related factors. RESULTS: We identified 103 hepatology guidelines published between January 2008 and September 2022 published by the AGA, ACG, AASLD, APASL, BSG, EASL, and KASL. The gender of 1096 of 1100 (99.6%) authors was determined. Therefore, a total of 1096 authors were included: 223 (20.3%) authors were women and 873 (79.7%) authors were men. Women comprised 14.6% of all first authors, and 20.4% of all senior authors were women. Only the AASLD had writing committees comprising more than 30% total women authors. The proportions of women senior authors and total women authors increased significantly during the study period (p < .05). Women first authors and women senior authors were more likely to publish guidelines with more women authors. Women first authors were less likely to be co-authors with men authors. CONCLUSIONS: Over the course of the past decade, the proportion of women authors of major hepatology guidelines has been low; however, this gender gap appears to be closing.

Prediction of in-hospital Mortality of Intensive Care Unit Patients with Acute Pancreatitis Based on an Explainable Machine Learning Algorithm.

BACKGROUND AND AIM: Acute pancreatitis (AP) is potentially fatal. Therefore, early identification of patients at a high mortality risk and timely intervention are essential. This study aimed to establish an explainable machine-learning model for predicting in-hospital mortality of intensive care unit (ICU) patients with AP. METHODS: Data on patients with AP, including demographics, vital signs, laboratory tests, comorbidities, treatment, complication, and severity scores, were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) and the eICU collaborative research database (eICU-CRD). Based on the data from MIMIC-IV, we used the least absolute shrinkage and selection operator algorithm to select variables and then established 9 machine-learning models and screened the optimal model. Data from the eICU-CRD were used for external validation. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy, decision curve, and calibration plots were used to assess the models' efficacy. Shapley's additive explanation values were used to explain the model. RESULTS: Gaussian naive Bayes (GNB) model had the best performance on the data from MIMIC-IV, with an AUC, accuracy, sensitivity, and specificity of 0.840, 0.787, 0.839, and 0.792, respectively. The GNB model also performed well on the data from the eICU-CRD, with an AUC, accuracy, sensitivity, and specificity of 0.862, 0.833, 0.848, and 0.763, respectively. According to Shapley's additive explanation values, the top 4 predictive factors were maximum red cell distribution width, minimum saturation of blood oxygen, maximum blood urea nitrogen, and the Sequential Organ Failure Assessment score. CONCLUSION: The GNB model demonstrated excellent performance and generalizability in predicting mortality in ICU patients with AP. Therefore, it can identify patients at a high mortality risk.

Application of a Machine Learning Predictive Model for Recurrent Acute Pancreatitis.

BACKGROUND AND AIM: Acute pancreatitis is the main cause of hospitalization for pancreatic disease. Some patients tend to have recurrent episodes after experiencing an episode of acute pancreatitis. This study aimed to construct predictive models for recurrent acute pancreatitis (RAP). METHODS: A total of 531 patients who were hospitalized for the first episode of acute pancreatitis at the Affiliated Hospital of Southwest Medical University from January 2018 to December 2019 were enrolled in the study. We confirmed whether the patients had a second episode until December 31, 2021, through an electronic medical record system and telephone or WeChat follow-up. Clinical and follow-up data of patients were collected and randomly allocated to the training and test sets at a ratio of 7:3. The training set was used to select the best model, and the selected model was tested with the test set. The area under the receiver operating characteristic curves, sensitivity, specificity, positive predictive value, negative predictive value, accuracy, decision curve, and calibration plots were used to assess the efficacy of the models. Shapley additive explanation values were used to explain the model. RESULTS: Considering multiple indices, XGBoost was the best model. The area under the receiver operating characteristic curves, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the XGBoost model in the test set were 0.779, 0.763, 0.883, 0.647, 0.341, and 0.922, respectively. According to the Shapley additive explanation values, drinking, smoking, higher levels of triglyceride, and the occurrence of ANC are associated with RAP. CONCLUSION: The XGBoost model shows good performance in predicting RAP, which may help identify high-risk patients.

Telithromycin resistance in Campylobacter mediated by 23S rRNA A2075G mutation and erm(B).

OBJECTIVES: Recently, epidemiological research has shown an unusually high prevalence of telithromycin-resistant Campylobacter. This study was designed to investigate the potential resistance mechanism of telithromycin resistance in Campylobacter. METHODS: A total of 122 Campylobacter isolates of chicken origin collected in 2019 from three regions of China were tested for susceptibility to telithromycin. The potential mechanism of resistance to telithromycin in Campylobacter was revealed through WGS analysis and natural transformation. RESULTS: In this study, 51.3% (61/119) of Campylobacter coli and 100.0% (3/3) of Campylobacter jejuni were resistant to telithromycin. erm(B) or A2075G mutation in 23S rRNA (23S_A2075G) was identified in the telithromycin-resistant C. coli. Cloning of the erm(B) or 23S_A2075G into C. jejuni NCTC 11168 resulted in a 256-fold increase in the MIC of telithromycin. MLST results indicated that various STs were involved in the dissemination of 23S_A2075G and erm(B). Phylogenetic analysis showed that the C. coli isolates with 23S_A2075G and erm(B) from chickens and humans were closely related. CONCLUSIONS: 23S_A2075G and erm(B), which have been widely spread in different genotypes of C. coli isolated from animals and humans, could mediate high levels of resistance to telithromycin in C. coli. C. coli containing 23S_A2075G or erm(B) are clonally related and have the potential to spread zoonotic diseases.

Signaling Lymphocytic Activation Molecule Family-7 Alleviates Corneal Inflammation by Promoting M2 Polarization.

BACKGROUND: Signaling lymphocytic activation molecule family-7 (SLAMF7) functions as an immune checkpoint molecule on macrophages in antitumor immunity. However, its role in bacterial infection remains largely unknown. METHODS: Bone marrow-derived macrophages (BMDMs) isolated from wild-type (WT) or SLAMF7 knockout (KO) mice were infected with bacteria or treated with lipopolysaccharide/interferon-γ to investigate the expression and function of SLAMF7 in macrophage polarization. A Pseudomonas aeruginosa keratitis murine model was established to explore the effect of SLAMF7 on P. aeruginosa keratitis using WT vs SLAMF7 KO mice, or recombinant SLAMF7 vs phosphate-buffered saline-treated mice, respectively. RESULTS: SLAMF7 expression was enhanced on M1-polarized or bacterial-infected macrophages, and infiltrating macrophages in P. aeruginosa-infected mouse corneas. SLAMF7 promoted M2 polarization by inducing STAT6 activation. In vivo data showed that SLAMF7 KO aggravated, while treatment with recombinant SLAMF7 alleviated, corneal inflammation and disease severity. In addition, blockage of M2 polarization by Arg-1 inhibitor abrogated the effect of recombinant SLAMF7 in disease progression. CONCLUSIONS: SLAMF7 expression in macrophages was induced upon M1 polarization or bacterial infection and alleviated corneal inflammation and disease progression of P. aeruginosa keratitis by promoting M2 polarization. These findings may provide a potential strategy for the treatment of P. aeruginosa keratitis.

Transmission, refraction and dark-field retrieval in hard X-ray grating interferometry.

A three-image algorithm is proposed to retrieve the sample's transmission, refraction and dark-field information in hard X-ray grating interferometry. Analytical formulae of the three-image algorithm are theoretically derived and presented, and evaluated by proof-of-principle synchrotron radiation experiments. The results confirm the feasibility of the proposed algorithm. The novelty of the proposed algorithm is that it allows versatile and tunable multimodal X-ray imaging by substantially relaxing the existing limitations on the lateral grating position. Furthermore, this algorithm can also be adapted for samples with negligible refraction, reducing the number of required sample measurements to two. Furthermore, the noise properties of the retrieved images are investigated in terms of the standard deviations. Theoretical models are presented and verified by synchrotron radiation measurements. It is shown that the noise standard deviations exhibit strong dependence on the lateral grating position, especially in the case of refraction and dark-field images. Further noise reduction and dose reduction can thus be possible by optimizing the lateral grating position for a selected region of interest. Those results can serve as general guidelines to optimize the data acquisition scheme for specific applications and problems.

Mucosal-associated invariant T-cells are severely reduced and exhausted in humans with chronic HBV infection.

Chronic hepatitis B virus (CHBV) infection is a major cause of liver diseases. Mucosal-associated invariant T (MAIT) cells are important for antiviral immunity in the liver, but the distinction between intrasinusoidal and peripheral MAIT cells in patients with CHBV infections remains unclear. PBMCs were obtained from patients with CHBV infections (n = 29) and age-matched controls (n = 46). Liver-associated mononuclear cells (LMCs) were collected from healthy donors (n = 29) and explanted livers (n = 19) from patients and used for phenotypic, functional and TCR diversity analyses. The percentages of both peripheral and intrasinusoidal MAIT cells were significantly reduced in the CHBV infection group compared to the control group. Peripheral MAIT cells from CHBV-infected patients expressed higher levels of HLA-DR, CD69, CD38 and PD-1 than those of controls. We also confirmed that peripheral MAIT cells in HBV patients had elevated expression T-cell exhaustion genes. Except for a difference in the level of PD-1, no differences were observed between the liver MAIT cells of the two groups. The production of IFN-α in peripheral MAIT cells of CHBV infection patients was lower than in control patients, but no such difference was observed in liver MAIT cells. Additionally, a distinct TCR signature was found in CHBV patients. Hence, we found distinct activities and functions in liver and peripheral MAIT cells of patients with CHBV infections.

Inhibition of allogeneic islet graft rejection by VISTA-conjugated liposome.

The Ig superfamily member V-domain Ig-containing suppressor of T-cell activation (VISTA) is a negative regulator with broad-spectrum activities and has reported that blockade of VISTA or combination with other negative checkpoint receptors sufficiently break tumor tolerance. However, it remains unclear whether VISTA could induce allogeneic T-cell hyporesponsiveness and inhibit allograft rejection. Here we found VISTA treatment significantly inhibited lymphocyte proliferation and activation in allogeneic MLR assay through impairing SYK-VAV pathway. Interestingly, though neither VISTA protein nor VISTA-Fc fusion protein administration exerted satisfactory immunosuppressive effect on allograft survival due to their short half-life in circulation, this problem was solved by conjugating VISTA protein on liposome by biotin-streptavidin system, which markedly prolonged its circulating half-life to 60 h. With islet transplant model, administration of VISTA-conjugated liposome could markedly prolong allograft survival by inhibition of SYK-VAV pathway, thus maintained the normal blood glucose level of recipients during treatment period. The results indicate VISTA is a promising therapeutic target to treat allograft rejection of islet transplantation.

Single-image phase retrieval for hard X-ray grating interferometry.

A single-image method is proposed for quantitative phase retrieval in hard X-ray grating interferometry. This novel method assumes a quasi-homogeneous sample, with a constant ratio between the real and imaginary parts of its complex refractive index. The method is first theoretically derived and presented, and then validated by synchrotron radiation experiments. Compared with the phase-stepping method, the presented approach abandons grating scanning and multiple image acquisition, and is therefore advantageous in terms of its simplified acquisition procedure and reduced data-collection times, which are especially important for applications such as in vivo imaging and phase tomography. Moreover, the sample's phase image, instead of its first derivative, is directly retrieved. In particular, the stripe artifacts encountered in the integrated phase images are significantly suppressed. The improved quality of the retrieved phase images can be beneficial for image interpretation and subsequent processing. Owing to its requirement for a single image and its robustness against noise, the present method is expected to find use in potential investigations in diverse applications.

A spontaneous pregnancy and successful delivery in a Chinese female with Silver-Russell syndrome accompanied by gestational diabetes mellitus.

Silver-Russell syndrome (SRS) is a heterogeneous disorder characterized by severe intrauterine and postnatal growth retardation and typical dysmorphic features including body asymmetry, relative macrocephaly, protruding forehead, and feeding difficulties. Previous descriptions of SRS focus on the management of specific issues in children. Herein, we present clinical and metabolic characteristics of an adult woman with SRS accompanied by gestational diabetes mellitus (GDM). Given the rare circumstances presented in our case, the emerging questions concerning the management of metabolic issues and fertility potential in adult SRS patient deserve more attention. Further, long-term follow up is essential to gain future insights into the natural history and optimal management in adulthood.

Two plant-derived aporphinoid alkaloids exert their antifungal activity by disrupting mitochondrial iron-sulfur cluster biosynthesis.

Eupolauridine and liriodenine are plant-derived aporphinoid alkaloids that exhibit potent inhibitory activity against the opportunistic fungal pathogens Candida albicans and Cryptococcus neoformans However, the molecular mechanism of this antifungal activity is unknown. In this study, we show that eupolauridine 9591 (E9591), a synthetic analog of eupolauridine, and liriodenine methiodide (LMT), a methiodide salt of liriodenine, mediate their antifungal activities by disrupting mitochondrial iron-sulfur (Fe-S) cluster synthesis. Several lines of evidence supported this conclusion. First, both E9591 and LMT elicited a transcriptional response indicative of iron imbalance, causing the induction of genes that are required for iron uptake and for the maintenance of cellular iron homeostasis. Second, a genome-wide fitness profile analysis showed that yeast mutants with deletions in iron homeostasis-related genes were hypersensitive to E9591 and LMT. Third, treatment of wild-type yeast cells with E9591 or LMT generated cellular defects that mimicked deficiencies in mitochondrial Fe-S cluster synthesis including an increase in mitochondrial iron levels, a decrease in the activities of Fe-S cluster enzymes, a decrease in respiratory function, and an increase in oxidative stress. Collectively, our results demonstrate that E9591 and LMT perturb mitochondrial Fe-S cluster biosynthesis; thus, these two compounds target a cellular pathway that is distinct from the pathways commonly targeted by clinically used antifungal drugs. Therefore, the identification of this pathway as a target for antifungal compounds has potential applications in the development of new antifungal therapies.

Serum Squamous Cell Carcinoma Antigen in Psoriasis: A Potential Quantitative Biomarker for Disease Severity.

BACKGROUND: An objective and quantitative method to evaluate psoriasis severity is important for practice and research in the precision care of psoriasis. OBJECTIVES: We aimed to explore serum biomarkers quantitatively in association with disease severity and treatment response in psoriasis patients, with serum squamous cell carcinoma antigen (SCCA) evaluated in this pilot study. METHODS: 15 psoriasis patients were treated with adalimumab. At different visits before and after treatment, quantitative body surface area (qBSA) was obtained from standardized digital body images of the patients, and the psoriasis area severity index (PASI) was also monitored. SCCA were detected by using microparticle enzyme immunoassay. The serum biomarkers were also tested in healthy volunteers as normal controls. Receiver-operating characteristic (ROC) curve analysis was used to explore the optimal cutoff point of SCCA to differentiate mild and moderate-to-severe psoriasis. RESULTS: The serum SCCA level in the psoriasis group was significantly higher (p < 0.05) than in the normal control group. After treatment, the serum SCCA levels were significantly decreased (p < 0.05). The SCCA level was well correlated with PASI and qBSA. In ROC analysis, when taking PASI = 10 or qBSA = 10% as the threshold, an optimal cutoff point of SCCA was found at 2.0 ng/mL with the highest Youden index. CONCLUSION: Serum SCCA might be a useful quantitative biomarker for psoriasis disease severity.

Two Distinctly Separated Emission Colorimetric NIR Fluorescent Probe for Fast Hydrazine Detection in Living Cells and Mice upon Independent Excitations.

Hydrazine is carcinogenic and highly toxic so that it can lead to serious environmental contamination and serious health risks although it has been extensively used as an effective propellant and an important reactive base in industry. Thus, the development of two-emission NIR fluorescent probes for rapid detection of hydrazine with high selectivity and sensitivity is of significance and of great challenge in both biological and environmental sciences. Here, we report a two-emission colorimetric fluorescent probe for the specific detection of hydrazine based on hydrazinolysis reaction under physiological conditions. In the presence of hydrazine, the probe showed an extremely remarkable fluorescence enhancement at 627 nm compared to the decrease at 814 nm excited at different wavelength in aqueous solution. This distinct difference of two emission intensities is suitable for detection of low concentration hydrazine with a detection limit of 0.38 ppb. Addition of hydrazine resulted in a remarkable color change from blue-green to red observed by the naked eye. Kinetic study indicated a fast response of the probe toward hydrazine in minutes. Furthermore, the probe can bioimage hydrazine in living HeLa cells and mice with low cytotoxicity and excellent biocompatibility.

A Fluorescent Probe for Hydrogen Peroxide in Vivo Based on the Modulation of Intramolecular Charge Transfer.

Endogenous hydrogen peroxide in vivo is related to many diseases, including cancer, diabetes, cardiovascular disease, and neurodegenerative disorders. Although many probes for detection of H2O2 have been explored, rapid response probes are still expected for in vivo application. Here, a new probe (PAM-BN-PB) was designed based on an intramolecular charge transfer (ICT) process with three parts: phenanthroimidazole, benzonitrile, and phenyl boronate. By modulation ICT process of PAM-BN-PB, H2O2 in solution systems can be detected with good selectivity. The exogenous and endogenous H2O2 in normal living cells, ischemia-reperfusion injury cells, and animals all can be imaged by PAM-BN-PB.