Reduction Triggered In Situ Polymerization in Living Mice

"Smart" biomaterials that are responsive to physiological or biochemical stimuli have found many biomedical applications for tissue engineering, therapeutics, and molecular imaging. In this work, we describe in situ polymerization of activatable biorthogonal small molecules in response to a reducing environment change in vivo. We designed a carbohydrate linker- and cyanobenzothiazole-cysteine condensation reaction-based small molecule scaffold that can undergo rapid condensation reaction upon physiochemical changes (such as a reducing environment) to form polymers (pseudopolysaccharide). The fluorescent and photoacoustic properties of a fluorophore-tagged condensation scaffold before and after the transformation have been examined with a dual-modality optical imaging method. These results confirmed the in situ polymerization of this probe after both local and systemic administration in living mice.

Engineered algae: A novel oxygen-generating system for effective treatment of hypoxic cancer

Microalgae, a naturally present unicellular microorganism, can undergo light photosynthesis and have been used in biofuels, nutrition, etc. Here, we report that engineered live microalgae can be delivered to hypoxic tumor regions to increase local oxygen levels and resensitize resistant cancer cells to both radio- and phototherapies. We demonstrate that the hypoxic environment in tumors is markedly improved by in situ-generated oxygen through microalgae-mediated photosynthesis, resulting in notably radiotherapeutic efficacy. Furthermore, the chlorophyll from microalgae produces reactive oxygen species during laser irradiation, further augmenting the photosensitizing effect and enhancing tumor cell apoptosis. Thus, the sequential combination of oxygen-generating algae system with radio- and phototherapies has the potential to create an innovative treatment strategy to improve the outcome of cancer management. Together, our findings demonstrate a novel approach that leverages the products of photosynthesis for treatment of tumors and provide proof-of-concept evidence for future development of algae-enhanced radio- and photodynamic therapy.

Pre-targeted Imaging of Protease Activity through In Situ Assembly of Nanoparticles

The pre-targeted imaging of enzyme activity has not been reported, likely owing to the lack of a mechanism to retain the injected substrate in the first step for subsequent labeling. Herein, we report the use of two bioorthogonal reactions-the condensation reaction of aromatic nitriles and aminothiols and the inverse-electron demand Diels-Alder reaction between tetrazine and trans-cyclooctene (TCO)-to develop a novel strategy for pre-targeted imaging of the activity of proteases. The substrate probe (TCO-C-SNAT4) can be selectively activated by an enzyme target (e.g. caspase-3/7), which triggers macrocyclization and subsequent in situ self-assembly into nanoaggregates retained at the target site. The tetrazine-imaging tag conjugate labels TCO in the nanoaggregates to generate selective signal retention for imaging in vitro, in cells, and in mice. Owing to the decoupling of enzyme activation and imaging tag immobilization, TCO-C-SNAT4 can be repeatedly injected to generate and accumulate more TCO-nanoaggregates for click labeling.

Carbon-coated FeCo nanoparticles as sensitive magnetic-particle-imaging tracers with photothermal and magnetothermal properties

The low magnetic saturation of iron oxide nanoparticles, which are developed primarily as contrast agents for magnetic resonance imaging, limits the sensitivity of their detection using magnetic particle imaging (MPI). Here, we show that FeCo nanoparticles that have a core diameter of 10 nm and bear a graphitic carbon shell decorated with poly(ethylene glycol) provide an MPI signal intensity that is sixfold and fifteenfold higher than the signals from the superparamagnetic iron oxide tracers VivoTrax and Feraheme, respectively, at the same molar concentration of iron. We also show that the nanoparticles have photothermal and magnetothermal properties and can therefore be used for tumour ablation in mice, and that they have high optical absorbance in a broad near-infrared region spectral range (wavelength, 700-1,200 nm), making them suitable as tracers for photoacoustic imaging. As sensitive multifunctional and multimodal imaging tracers, carbon-coated FeCo nanoparticles may confer advantages in cancer imaging and hyperthermia therapy.

Exploring the Condensation Reaction between Aromatic Nitriles and Amino Thiols To Optimize In Situ Nanoparticle Formation for the Imaging of Proteases and Glycosidases in Cells

The condensation reaction between 6-hydroxy-2-cyanobenzothiazole (CBT) and cysteine has been shown for various applications such as site-specific protein labelling and in vivo cancer imaging. This report further expands the substrate scope of this reaction by varying the substituents on aromatic nitriles and amino thiols and testing their reactivity and ability to form nanoparticles for cell imaging. The structure-activity relationship study leads to the identification of the minimum structural requirement for the macrocyclization and assembly process in forming nanoparticles. One of the scaffolds made of 2-pyrimidinecarbonitrile and cysteine joined by a benzyl linker was applied to design fluorescent probes for imaging caspase-3/7 and β-galactosidase activity in live cells. These results demonstrate the generality of this system for imaging hydrolytic enzymes.

[The clinical observation of serum specific biomarkers in patients with chronic graft-versus-host disease]

目的

研究异基因造血干细胞移植后患者血清生物标志物表达水平对慢性移植物抗宿主病（cGVHD）早期诊断的价值。

方法

采用液相悬浮芯片法检测接受异基因造血干细胞移植后发生和未发生cGVHD患者5种血清蛋白标志物（IL-1b、IL-16、CXCL9、CCL19、CCL17）表达水平。

结果

相较于未发生cGVHD的对照组，cGVHD患者血清中CXCL9、CCL17表达水平显著升高（P<0.05），其中CCL17与cGVHD的疾病严重程度相关（P<0.001）；CXCL9在皮肤损害的cGVHD患者血清中显著升高（P<0.01），CCL17在肝脏为靶器官的cGVHD患者中表达水平显著升高（P<0.01）。

结论

CXCL9联合CCL17可作为cGVHD的血清生物标志物，对辅助cGVHD诊断和评估严重程度有一定参考价值。

In Vivo Optical Performance of a New Class of Near-Infrared-Emitting Conjugated Polymers: Borylated PF8-BT

Borylated poly(fluorene-benzothiadiazoles) (PF8-BT) are π-conjugated polymers (CPs) with deep-red/near-infrared (NIR) absorption and emission profiles suitable for in vivo optical imaging. A fully borylated PF8-BT derivative (P4) was encapsulated in pegylated poly(lactic-co-glycolic acid) (PEG-PLGA) nanoparticles and compared with a reference NIR-emitting CP (PCPDTBT) or indocyanine green (ICG). All formulations satisfied quality requirements for parenterally administered diagnostics. P4 nanoparticles had higher quantum yield (2.3%) than PCPCDTBT (0.01%) or ICG nanoparticles (1.1%). The signal/background ratios (SBRs) of CP systems P4 and PCPDTBT in a phantom mouse (λ_em = 820 nm) increased linearly with fluorophore mass (12.5-100 μg/mL), while the SBRs of ICG decreased above 25 μg/mL. P4 nanoparticles experienced <10% photobleaching over 10 irradiations (PCPDTBT: ∼25% and ICG: >44%). In a mouse tumor xenograft model, P4 nanoparticles showed a 5-fold higher SBR than PCPDTBT particles with fluorophore accumulation in the liver > spleen > tumor. Blood chemistry and tissue histology showed no abnormalities compared to untreated animals after a single administration.

Rapid and specific labeling of single live Mycobacterium tuberculosis with a dual-targeting fluorogenic probe

Tuberculosis (TB) remains a public health crisis and a leading cause of infection-related death globally. Although in high demand, imaging technologies that enable rapid, specific, and nongenetic labeling of live Mycobacterium tuberculosis (Mtb) remain underdeveloped. We report a dual-targeting strategy to develop a small molecular probe (CDG-DNB3) that can fluorescently label single bacilli within 1 hour. CDG-DNB3 fluoresces upon activation of the β-lactamase BlaC, a hydrolase naturally expressed in Mtb, and the fluorescent product is retained through covalent modification of the Mtb essential enzyme decaprenylphosphoryl-β-d-ribose 2'-epimerase (DprE1). This dual-targeting probe not only discriminates live from dead Bacillus Calmette-Guérin (BCG) but also shows specificity for Mtb over other bacterial species including 43 nontuberculosis mycobacteria (NTM). In addition, CDG-DNB3 can image BCG phagocytosis in real time, as well as Mtb in patients' sputum. Together with a low-cost, self-driven microfluidic chip, we have achieved rapid labeling and automated quantification of live BCG. This labeling approach should find many potential applications for research toward TB pathogenesis, treatment efficacy assessment, and diagnosis.

Cross-sectional study of the prevalence, causes and management of hospital-onset diarrhoea

BACKGROUND

The National Health Service in England advises hospitals collect data on hospital-onset diarrhoea (HOD). Contemporaneous data on HOD are lacking.

AIM

To investigate prevalence, aetiology and management of HOD on medical, surgical and elderly-care wards.

METHODS

A cross-sectional study in a volunteer sample of UK hospitals, which collected data on one winter and one summer day in 2016. Patients admitted ≥72 h were screened for HOD (definition: ≥2 episodes of Bristol Stool Type 5-7 the day before the study, with diarrhoea onset >48 h after admission). Data on HOD aetiology and management were collected prospectively.

FINDINGS

Data were collected on 141 wards in 32 hospitals (16 acute, 16 teaching). Point-prevalence of HOD was 4.5% (230/5142 patients; 95% confidence interval (CI) 3.9-5.0%). Teaching hospital HOD prevalence (5.9%, 95% CI 5.1-6.9%) was twice that of acute hospitals (2.8%, 95% CI 2.1-3.5%; odds ratio 2.2, 95% CI 1.7-3.0). At least one potential cause was identified in 222/230 patients (97%): 107 (47%) had a relevant underlying condition, 125 (54%) were taking antimicrobials, and 195 (85%) other medication known to cause diarrhoea. Nine of 75 tested patients were Clostridium difficile toxin positive (4%). Eighty (35%) patients had a documented medical assessment of diarrhoea. Documentation of HOD in medical notes correlated with testing for C. difficile (78% of those tested vs 38% not tested, P<0.001). One-hundred and forty-four (63%) patients were not isolated following diarrhoea onset.

CONCLUSION

HOD is a prevalent symptom affecting thousands of patients across the UK health system each day. Most patients had multiple potential causes of HOD, mainly iatrogenic, but only a third had medical assessment. Most were not tested for C. difficile and were not isolated.

Theranostic nanoparticles enhance the response of glioblastomas to radiation

Despite considerable progress with our understanding of glioblastoma multiforme (GBM) and the precise delivery of radiotherapy, the prognosis for GBM patients is still unfavorable with tumor recurrence due to radioresistance being a major concern. We recently developed a cross-linked iron oxide nanoparticle conjugated to azademethylcolchicine (CLIO-ICT) to target and eradicate a subpopulation of quiescent cells, glioblastoma initiating cells (GICs), which could be a reason for radioresistance and tumor relapse. The purpose of our study was to investigate if CLIO-ICT has an additive therapeutic effect to enhance the response of GBMs to ionizing radiation.

Methods: NSG™ mice bearing human GBMs and C57BL/6J mice bearing murine GBMs received CLIO-ICT, radiation, or combination treatment. The mice underwent pre- and post-treatment magnetic resonance imaging (MRI) scans, bioluminescence imaging (BLI), and histological analysis. Tumor nanoparticle enhancement, tumor flux, microvessel density, GIC, and apoptosis markers were compared between different groups using a one-way ANOVA and two-tailed Mann-Whitney test. Additional NSG™ mice underwent survival analyses with Kaplan-Meier curves and a log rank (Mantel-Cox) test.

Results: At 2 weeks post-treatment, BLI and MRI scans revealed significant reduction in tumor size for CLIO-ICT plus radiation treated tumors compared to monotherapy or vehicle-treated tumors. Combining CLIO-ICT with radiation therapy significantly decreased microvessel density, decreased GICs, increased caspase-3 expression, and prolonged the survival of GBM-bearing mice. CLIO-ICT delivery to GBM could be monitored with MRI. and was not significantly different before and after radiation. There was no significant caspase-3 expression in normal brain at therapeutic doses of CLIO-ICT administered.

Conclusion: Our data shows additive anti-tumor effects of CLIO-ICT nanoparticles in combination with radiotherapy. The combination therapy proposed here could potentially be a clinically translatable strategy for treating GBMs.

Effect of direct defect closure during laparoscopic inguinal hernia repair ("TEP/TAPP plus" technique) on post-operative outcomes

PURPOSE

Seroma formation and recurrence in large inguinal hernia still remain an important clinical complication despite decades since the advent of mesh repair.

METHODS

In our prospective comparative analysis, we want to evaluate the effect of direct hernia defect closure on surgical outcomes in patients undergoing laparoscopic inguinal hernia repair in two tertiary care institutions in Singapore. The direct hernia defects were closed with non-absorbable sutures incorporating the pseudosac.

RESULTS

A group of 241 patients underwent laparoscopic inguinal hernia mesh repair for a total of 378 direct defects from April 2014 to July 2018. Of these patients, 98 (40.6%) patients underwent hernia repair without closure of their direct defect while 143 (59.4%) patients underwent direct defect closure. No significant differences were observed between the two patient populations' demographic information and the mean operative time. A total of 219 direct defects were closed and 159 direct defects were not repaired. Compared to the group that did not undergo direct defect closure, the group that had closure of the direct defects demonstrated a statistically significant reduction in recurrence (4.4% versus 0.9%, p = 0.036) and seroma formation (12.6% versus 6.4%, p = 0.045).

CONCLUSION

Direct defect closure has proven to be effective in reducing recurrence and seroma formation post-operatively in patients undergoing laparoscopic inguinal hernia repair. Randomized controlled trials will be required to further evaluate these outcomes.

A Magneto-Optical Nanoplatform for Multimodality Imaging of Tumors in Mice

Multimodality imaging involves the use of more imaging modes to image the same living subjects and is now generally preferred in clinics for cancer imaging. Here we present multimodality-Magnetic Particle Imaging (MPI), Magnetic Resonance Imaging (MRI), Photoacoustic, Fluorescent-nanoparticles (termed MMPF NPs) for imaging tumor xenografts in living mice. MMPF NPs provide long-term (more than 2 months), dynamic, and accurate quantification, in vivo, of NPs and in real time by MPI. Moreover, MMPF NPs offer ultrasensitive MPI imaging of tumors (the tumor ROI increased by 30.6 times over that of preinjection). Moreover, the nanoparticle possessed a long-term blood circulation time (half-life at 49 h) and high tumor uptake (18% ID/g). MMPF NPs have been demonstrated for imaging breast and brain tumor xenografts in both subcutaneous and orthotopic models in mice via simultaneous MPI, MRI, fluorescence, and photoacoustic imaging with excellent tumor contrast to normal tissues.

A Near-Infrared Phosphorescent Nanoprobe Enables Quantitative, Longitudinal Imaging of Tumor Hypoxia Dynamics during Radiotherapy

Hypoxia plays a key role in tumor resistance to radiotherapy. It is important to study hypoxia dynamics during radiotherapy to improve treatment planning and prognosis. Here, we describe a luminescent nanoprobe, composed of a fluorescent semiconducting polymer and palladium complex, for quantitative longitudinal imaging of tumor hypoxia dynamics during radiotherapy. The nanoprobe was designed to provide high sensitivity and reversible response for the subtle change in hypoxia over a narrow range (0-30 mmHg O₂), which spans the oxygen range where tumors have limited radiosensitivity. Following intravenous administration, the nanoprobe efficiently accumulated in and distributed across the tumor, including the hypoxic region. The ratio between emissions at 700 and 800 nm provided quantitative mapping of hypoxia across the entire tumor. The nanoprobe was used to image tumor hypoxia dynamics over 7 days during fractionated radiotherapy and revealed that high fractional dose (10 Gy) was more effective in improving tumor reoxygenation than low dose (2 Gy), and the effect tended to persist longer in smaller or more radiosensitive tumors. Our results also indicated the importance of the reoxygenation efficiency of the first fraction in the prediction of the radiation treatment outcome. In summary, this work has established a new nanoprobe for highly sensitive, quantitative, and longitudinal imaging of tumor hypoxia dynamics following radiotherapy, and demonstrated its value for assessing the efficacy of radiotherapy and radiation treatment planning. SIGNIFICANCE: This study presents a novel nanoagent for the visualization and quantification of tumor hypoxia.

Bright sub-20-nm cathodoluminescent nanoprobes for electron microscopy

Electron microscopy has been instrumental in our understanding of complex biological systems. Although electron microscopy reveals cellular morphology with nanoscale resolution, it does not provide information on the location of different types of proteins. An electron-microscopy-based bioimaging technology capable of localizing individual proteins and resolving protein-protein interactions with respect to cellular ultrastructure would provide important insights into the molecular biology of a cell. Here, we synthesize small lanthanide-doped nanoparticles and measure the absolute photon emission rate of individual nanoparticles resulting from a given electron excitation flux (cathodoluminescence). Our results suggest that the optimization of nanoparticle composition, synthesis protocols and electron imaging conditions can lead to sub-20-nm nanolabels that would enable high signal-to-noise localization of individual biomolecules within a cellular context. In ensemble measurements, these labels exhibit narrow spectra of nine distinct colours, so the imaging of biomolecules in a multicolour electron microscopy modality may be possible.

[18F]-SuPAR: A Radiofluorinated Probe for Noninvasive Imaging of DNA Damage-Dependent Poly(ADP-ribose) Polymerase Activity

Poly(ADP ribose) polymerase (PARP) enzymes generate poly(ADP ribose) post-translational modifications on target proteins for an array of functions centering on DNA and cell stress. PARP isoforms 1 and 2 are critically charged with the surveillance of DNA integrity and are the first line guardians of the genome against DNA breaks. Here we present a novel probe ([¹⁸F]-SuPAR) for noninvasive imaging of PARP-1/2 activity using positron emission tomography (PET). [¹⁸F]-SuPAR is a radiofluorinated nicotinamide adenine dinucleotide (NAD) analog that can be recognized by PARP-1/2 and incorporated into the long branched polymers of poly(ADP ribose) (PAR). The measurement of PARP-1/2 activity was supported by a reduction of radiotracer uptake in vivo following PARP-1/2 inhibition with talazoparib treatment, a potent PARP inhibitor recently approved by FDA for treatment of breast cancer, as well as ex vivo colocalization of radiotracer analog and poly(ADP ribose). With [¹⁸F]-SuPAR, we were able to map the dose- and time-dependent activation of PARP-1/2 following radiation therapy in breast and cervical cancer xenograft mouse models. Tumor response to therapy was determined by [¹⁸F]-SuPAR PET within 8 h of administration of a single dose of radiation equivalent to one round of stereotactic ablative radiotherapy.

A Review of Magnetic Particle Imaging and Perspectives on Neuroimaging

Magnetic particle imaging is an emerging tomographic technique with the potential for simultaneous high-resolution, high-sensitivity, and real-time imaging. Magnetic particle imaging is based on the unique behavior of superparamagnetic iron oxide nanoparticles modeled by the Langevin theory, with the ability to track and quantify nanoparticle concentrations without tissue background noise. It is a promising new imaging technique for multiple applications, including vascular and perfusion imaging, oncology imaging, cell tracking, inflammation imaging, and trauma imaging. In particular, many neuroimaging applications may be enabled and enhanced with magnetic particle imaging. In this review, we will provide an overview of magnetic particle imaging principles and implementation, current applications, promising neuroimaging applications, and practical considerations.

[Clinicopathologic features of breast lymphoma in core needle biopsy]

Objective: To investigate the clinicopathologic features and differential diagnosis of breast lymphoma in core needle biopsy. Methods: Seventy-two cases of breast lymphoma in core needle biopsy between 2011 and 2016 were extracted from the pathology database of Fudan University Shanghai Cancer Center. The clinicopathologic features were analyzed. The histological diagnosis of the tumors was based on the WHO classifications of tumors of hematopoietic and lymphoid tissues. Immunohistochemistry and molecular methods were performed to detect related antigens and genes. Results: Seventy-one patients were female and one was male. The median age was 54 years. The tumors were located in the right breast in 32 (44.4%) patients and in the left breast in 40 (55.6%) patients. Seven patients had a previous history of lymphoma. Most of the cases presented as a single and painless breast mass. Sixty-three patients received systemic treatment, and nine patients received systemic therapy after excision. The common morphological feature was that single tumor cells infiltrated the stroma, without cohesiveness between tumor cells, and lacking glandular or nested epithelioid structures. The normal ductal and lobular structures of the mammary gland were typically preserved. The tumor cells in some cases were distributed in single rows, and should be differentiated from invasive carcinoma. All cases were positive for LCA, negative for CK. Sixty-eight cases were classified as B-cell lymphoma, including 63 cases (87.5%) of diffuse large B-cell lymphoma (DLBCL; including 3 cases of EBV-positive DLBCL and 60 cases of DLBCL, NOS), two cases of Burkitt lymphoma, one case of mantle cell lymphoma, one case of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue and one case of precursor B lymphoblastic leukemia/lymphoma. The remaining cases included two peripheral T-cell lymphoma (NOS), one extranodal NK/T cell lymphoma, nasal type and one myeloid sarcoma. In 63 cases of DLBCL, 22 cases (34.9%) expressed germinal center B-cell-like (GCB) phenotype and 41 cases (65.1%) showed non-germinal center B-cell-like (non-GCB) phenotype. Conclusions: Core needle biopsy could be the preferred method for diagnosis of breast lymphoma. Diffuse large B-cell lymphoma is the most common histologic type of breast lymphoma, and non-GCB subtype is more frequent than GCB subtype.