Real-time volumetric reconstruction of biological dynamics with light-field microscopy and deep learning.

Light-field microscopy has emerged as a technique of choice for high-speed volumetric imaging of fast biological processes. However, artifacts, nonuniform resolution and a slow reconstruction speed have limited its full capabilities for in toto extraction of dynamic spatiotemporal patterns in samples. Here, we combined a view-channel-depth (VCD) neural network with light-field microscopy to mitigate these limitations, yielding artifact-free three-dimensional image sequences with uniform spatial resolution and high-video-rate reconstruction throughput. We imaged neuronal activities across moving Caenorhabditis elegans and blood flow in a beating zebrafish heart at single-cell resolution with volumetric imaging rates up to 200 Hz.

Adhere to the Chinese dietary guidelines associated with better subjective well-being: evidence from a cross-sectional survey and a daily diary investigation.

BACKGROUND: Subjective well-being (SWB) plays an essential role in general health. Although beneficial effects of selected micronutrients and foods on SWB have been reported, they do not reflect the impact of the habitual diet on SWB. Therefore, the purpose of this study is to investigate the association between adherence to the Chinese Dietary Guidelines (CDG) with SWB. METHODS: This study combined a cross-sectional survey and a daily diary investigation. The cross-sectional survey was conducted on 1,433 students from 8 universities in southern China between October and November 2020. The daily diary investigation was conducted in November 2022, collecting 10-day daily data from 115 students at two universities in southern China over ten consecutive days, resulting in 1,020 valid matched daily responses. Adherence to the CDG was assessed by the China Prime Diet Quality Score (CPDQS), SWB was measured by the Index of Well-being (IWB) and the Affect Valuation Index (AVI). Correlation analysis, multiple regression analyses, and hierarchical regression were conducted to examine the associations of adherence to the CDG with its components, and SWB. RESULTS: The cross-sectional survey revealed significant predictors of SWB, including adherence to the CDG (ß = 0.24, p<0.001) and its components: cereals and tubers (ß = 0.07, p = 0.024), vegetables and fruits (ß = 0.11, p<0.001), dairy/soy/nuts (ß = 0.11, p = 0.002), and condiments and alcoholic beverages (ß = 0.08, p = 0.002). The daily diary investigation showed positive associations between adherence to the CDG (ß = 0.19, p<0.001), and its components: vegetables and fruits (ß = 0.11, p = 0.001), dairy/soy/nuts (ß = 0.06, p = 0.009), animal source food (ß = 0.06, p = 0.026), and condiments and alcoholic beverages (ß = 0.07, p = 0.026), with higher levels of daily SWB. CONCLUSIONS: Adherence to healthy dietary patterns such as the CDG, rather than focusing on individual components in isolation, is associated with better SWB. Furthermore, the consumption of CDG components had an impact on SWB, although the specific effects varied between the two studies. This study offers modest evidence supporting the role of the CDG in promoting positive mental health.

Tetraphenylporphyrin-based Chelating Ligand Additive as a Molecular Sieving Interfacial Barrier toward Durable Aqueous Zinc Metal Batteries.

The sustained water consumption and uncontrollable dendrite growth strongly hamper the practical applications of rechargeable zinc (Zn) metal batteries (ZMBs). Herein, for the first time, we demonstrate that trace amount of chelate ligand additive can serve as a "molecular sieve-like" interfacial barrier and achieve highly efficient Zn plating/stripping. As verified by theoretical modeling and experimental investigations, the benzenesulfonic acid groups on the additive molecular not only facilitates its water solubility and selective adsorption on the Zn anode, but also effectively accelerates the de-solvation kinetics of Zn2+ . Meanwhile, the central porphyrin ring on the chelate ligand effectively expels free water molecules from Zn2+ via chemical binding against hydrogen evolution, and reversibly releases the captured Zn2+ to endow a dendrite-free Zn deposition. By virtue of this non-consumable additive, high average Zn plating/stripping efficiency of 99.7 % over 2100 cycles together with extended lifespan and suppressed water decomposition in the Zn||MnO2 full battery were achieved, thus opening a new avenue for developing highly durable ZMBs.

TNFR2 is a potent prognostic biomarker for post-transplant lung metastasis in patients with hepatocellular carcinoma.

Objective: Lung metastasis is a common and fatal complication of liver transplantation for hepatocellular carcinoma (HCC). The precise prediction of post-transplant lung metastasis in the early phase is of great value. Methods: The mRNA profiles of primary and paired lung metastatic lesions were analyzed to determine key signaling pathways. We enrolled 241 HCC patients who underwent liver transplantation from three centers. Tissue microarrays were used to evaluate the prognostic capacity of tumor necrosis factor (TNF), tumor necrosis factor receptor 1 (TNFR1), and TNFR2, particularly for post-transplant lung metastasis. Results: Comparison of primary and lung metastatic lesions revealed that the TNF-dependent signaling pathway was related to lung metastasis of HCC. The expression of TNF was degraded in comparison to that in para-tumor tissues (P<0.001). The expression of key receptors in the TNF-dependent signaling pathway, TNFR1 and TNFR2, was higher in HCC tissues than in para-tumor tissues (P<0.001). TNF and TNFR1 showed no relationship with patients' outcomes, whereas elevated TNFR2 in tumor tissue was significantly associated with worse overall survival (OS) and increased recurrence risk (5-year OS rate: 31.9% vs. 62.5%, P<0.001). Notably, elevated TNFR2 levels were also associated with an increased risk of post-transplant lung metastasis (hazard ratio: 1.146; P<0.001). Cox regression analysis revealed that TNFR2, Hangzhou criteria, age, and hepatitis B surface antigen were independent risk factors for post-transplant lung metastasis, and a novel nomogram was established accordingly. The nomogram achieved excellent prognostic efficiency (area under time-dependent receiver operating characteristic =0.755, concordance-index =0.779) and was superior to conventional models, such as the Milan criteria. Conclusions: TNFR2 is a potent prognostic biomarker for predicting post-transplant lung metastasis in patients with HCC. A nomogram incorporating TNFR2 deserves to be a helpful prognostic tool in liver transplantation for HCC.

Biosynthesis of Tasikamides via Pathway Coupling and Diazonium-Mediated Hydrazone Formation.

Naturally occurring hydrazones are rare despite the ubiquitous usage of synthetic hydrazones in the preparation of organic compounds and functional materials. In this study, we discovered a family of novel microbial metabolites (tasikamides) that share a unique cyclic pentapeptide scaffold. Surprisingly, tasikamides A-C (1-3) contain a hydrazone group (C═N─N) that joins the cyclic peptide scaffold to an alkyl 5-hydroxylanthranilate (AHA) moiety. We discovered that the biosynthesis of 1-3 requires two discrete gene clusters, with one encoding a nonribosomal peptide synthetase (NRPS) pathway for assembling the cyclic peptide scaffold and another encoding the AHA-synthesizing pathway. The AHA gene cluster encodes three ancillary enzymes that catalyze the diazotization of AHA to yield an aryl diazonium species (diazo-AHA). The electrophilic diazo-AHA undergoes nonenzymatic Japp-Klingemann coupling with a ß-keto aldehyde-containing cyclic peptide precursor to furnish the hydrazone group and yield 1-3. The studies together unraveled a novel mechanism whereby specialized metabolites are formed by the coupling of two biosynthetic pathways via an unprecedented in vivo Japp-Klingemann reaction. The findings raise the prospect of exploiting the arylamine-diazotizing enzymes (AAD) for the in vivo synthesis of aryl compounds and modification of biological macromolecules.

A hybrid of light-field and light-sheet imaging to study myocardial function and intracardiac blood flow during zebrafish development.

Biomechanical forces intimately contribute to cardiac morphogenesis. However, volumetric imaging to investigate the cardiac mechanics with high temporal and spatial resolution remains an imaging challenge. We hereby integrated light-field microscopy (LFM) with light-sheet fluorescence microscopy (LSFM), coupled with a retrospective gating method, to simultaneously access myocardial contraction and intracardiac blood flow at 200 volumes per second. While LSFM allows for the reconstruction of the myocardial function, LFM enables instantaneous acquisition of the intracardiac blood cells traversing across the valves. We further adopted deformable image registration to quantify the ventricular wall displacement and particle tracking velocimetry to monitor intracardiac blood flow. The integration of LFM and LSFM enabled the time-dependent tracking of the individual blood cells and the differential rates of segmental wall displacement during a cardiac cycle. Taken together, we demonstrated a hybrid system, coupled with our image analysis pipeline, to simultaneously capture the myocardial wall motion with intracardiac blood flow during cardiac development.

Coded-pulse-bunch-laser-based single-photon lidar for fast long-distance ranging.

Laser ranging based on a single-photon avalanche diode (SPAD), offering single-photon level high sensitivity, has been widely adopted in light detection and ranging (lidar) systems for long-distance ranging and imaging applications. Count detection through multiple pulses is commonly used when considering the existence of dark counting and strong background counting during the daytime, which improves the signal-to-noise ratio but at the expense of low detection speed. Here, we report a novel coded-pulse-bunch-laser-based single-photon lidar system, which aims to improve the ranging speed greatly and to expand the unambiguous distance to several kilometers. The schematic principle and construction of the lidar system, as well as the encoding method, are introduced. The time-of-flight (TOF) ranging information is extracted through real-time correlation between the transmitted pulse-bunch patterns and the received echo signals in a field-programmable gate array (FPGA). A daytime ranging experiment is demonstrated on a non-cooperative mountain target that is 5.4 km away. The method will be of great potential in fast three-dimension (3D) single-photon lidar imaging application for its relatively high data refreshing rate and large unambiguous distance.

Computational Analysis of Cardiac Contractile Function.

PURPOSE OF REVIEW: Heart failure results in the high incidence and mortality all over the world. Mechanical properties of myocardium are critical determinants of cardiac function, with regional variations in myocardial contractility demonstrated within infarcted ventricles. Quantitative assessment of cardiac contractile function is therefore critical to identify myocardial infarction for the early diagnosis and therapeutic intervention. RECENT FINDINGS: Current advancement of cardiac functional assessments is in pace with the development of imaging techniques. The methods tailored to advanced imaging have been widely used in cardiac magnetic resonance, echocardiography, and optical microscopy. In this review, we introduce fundamental concepts and applications of representative methods for each imaging modality used in both fundamental research and clinical investigations. All these methods have been designed or developed to quantify time-dependent 2-dimensional (2D) or 3D cardiac mechanics, holding great potential to unravel global or regional myocardial deformation and contractile function from end-systole to end-diastole. Computational methods to assess cardiac contractile function provide a quantitative insight into the analysis of myocardial mechanics during cardiac development, injury, and remodeling.

Use of Robots in Critical Care: Systematic Review.

BACKGROUND: The recent focus on the critical setting, especially with the COVID-19 pandemic, has highlighted the need for minimizing contact-based care and increasing robotic use. Robotics is a rising field in the context of health care, and we sought to evaluate the use of robots in critical care settings. OBJECTIVE: Although robotic presence is prevalent in the surgical setting, its role in critical care has not been well established. We aimed to examine the uses and limitations of robots for patients who are critically ill. METHODS: This systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. MEDLINE, Embase, IEEE Xplore, and ACM Library were searched from their inception to December 23, 2021. Included studies involved patients requiring critical care, both in intensive care units or high-dependency units, or settings that required critical care procedures (eg, intubation and cardiopulmonary resuscitation). Randomized trials and observational studies were included. RESULTS: A total of 33 studies were included. The greatest application of robots in the intensive care unit was in the field of telepresence, whereby robots proved advantageous in providing a reduced response time, earlier intervention, and lower mortality rates. Challenges of telepresence included regulatory and financial barriers. In therapy and stroke rehabilitation, robots achieved superior clinical outcomes safely. Robotic use in patient evaluation and assessment was mainly through ultrasound evaluation, obtaining satisfactory to superior results with the added benefits of remote assessment, time savings, and increased efficiency. Robots in drug dispensing and delivery increased efficiency and generated cost savings. All the robots had technological limitations and hidden costs. CONCLUSIONS: Overall, our results show that robotic use in critical care settings is a beneficial, effective, and well-received intervention that delivers significant benefits to patients, staff, and hospitals. Looking ahead, it is necessary to form strong ethical and legislative frameworks and overcome various regulatory and financial barriers. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD42021234162; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=234162.

Extended-Spectrum ß-Lactamase-Producing and mcr-1-Positive Escherichia coli from the Gut Microbiota of Healthy Singaporeans.

Multidrug-resistant (MDR) Escherichia coli strains that carry extended-spectrum ß-lactamases (ESBLs) or colistin resistance gene mcr-1 have been identified in the human gut at an increasing incidence worldwide. In this study, we isolated and characterized MDR Enterobacteriaceae from the gut microbiota of healthy Singaporeans and show that the detection rates for ESBL-producing and mcr-positive Enterobacteriaceae are 25.7% (28/109) and 7.3% (8/109), respectively. Whole-genome sequencing analysis of the 37 E. coli isolates assigned them into 25 sequence types and 6 different phylogroups, suggesting that the MDR E. coli gut colonizers are highly diverse. We then analyzed the genetic context of the resistance genes and found that composite transposons played important roles in the cotransfer of blaCTX-M-15/55 and qnrS1, as well as the acquisition of mcr-1. Furthermore, comparative genomic analysis showed that 12 of the 37 MDR E. coli isolates showed high similarity to ESBL-producing E. coli isolates from raw meat products in local markets. By analyzing the core genome single nucleotide polymorphisms (SNPs) shared by these isolates, we identified possible clonal transmission of an MDR E. coli clone between human and raw meat, as well as a group of highly similar IncI2 (Delta) plasmids that might be responsible for the dissemination of mcr-1 in a much wider geographic region. Together, these results suggest that antibiotic resistance may be transmitted between different environmental settings by the expansion of MDR E. coli clones, as well as by the dissemination of resistance plasmids. IMPORTANCE The human gut can harbor both antibiotic-resistant and virulent Escherichia coli which may subsequently cause infections. In this study, we found that multidrug-resistant (MDR) E. coli isolates from the gut of healthy Singaporeans carry a diverse range of antibiotic resistance mechanisms and virulence factor genes and are highly diverse. By comparing their genomes with the extended-spectrum ß-lactamase (ESBL)-producing E. coli isolates from raw meat products that were sampled at a similar time from local markets, we detected an MDR E. coli clone that was possibly transmitted between humans and raw meat products. Furthermore, we also found that a group of resistance plasmids might be responsible for the dissemination of colistin resistance gene mcr-1 in Singapore, Malaysia, and Europe. Our findings call for better countermeasures to block the transmission of antibiotic resistance.

Acousto-optic frequency shifted comb laser-based micro-Doppler detection for moving target identification.

We present a preliminary experimental demonstration of an acousto-optic frequency shifted (AOFS) comb laser-based micro-Doppler detection system for moving object identification. The AOFS comb laser was constructed by successively frequency shifting a single-frequency seed laser at 1063.8 nm using an acousto-optic modulator in an amplified fiber loop, which resulted in a stable pulse output with a pulse repetition rate around 150 MHz and pulse duration of about 200 ps. The AOFS comb pulse was amplified and then directed through a fiber circulator first and then an optical lens onto a moving object, which featured both linear translation and rotation. The micro-Doppler signal of the rotation was derived from the heterodyne detection of the pulse echo comb laser and the continuous-wave single-frequency local laser. It is believed that such an AOFS comb laser-based sensing system is of great potential for micro-Doppler detection of high-speed targets owing to its long-term stability and compactness.

Ribosome protection by antibiotic resistance ATP-binding cassette protein.

The ribosome is one of the richest targets for antibiotics. Unfortunately, antibiotic resistance is an urgent issue in clinical practice. Several ATP-binding cassette family proteins confer resistance to ribosome-targeting antibiotics through a yet unknown mechanism. Among them, MsrE has been implicated in macrolide resistance. Here, we report the cryo-EM structure of ATP form MsrE bound to the ribosome. Unlike previously characterized ribosomal protection proteins, MsrE is shown to bind to ribosomal exit site. Our structure reveals that the domain linker forms a unique needle-like arrangement with two crossed helices connected by an extended loop projecting into the peptidyl-transferase center and the nascent peptide exit tunnel, where numerous antibiotics bind. In combination with biochemical assays, our structure provides insight into how MsrE binding leads to conformational changes, which results in the release of the drug. This mechanism appears to be universal for the ABC-F type ribosome protection proteins.

Emergence of tigecycline- and eravacycline-resistant Tet(X4)-producing Enterobacteriaceae in the gut microbiota of healthy Singaporeans.

OBJECTIVES: The recently discovered tigecycline-inactivating enzyme Tet(X4) can confer high-level tigecycline resistance on its hosts, which makes it a public health concern. This study focused on isolation and screening of Tet(X4)-positive Enterobacteriaceae from the gut microbiota of a cohort of healthy individuals in Singapore. METHODS: MinION and Illumina sequencing was performed to obtain the complete genome sequences of Escherichia coli 2EC1-1 and 94EC. Subsequently, 109 human faecal samples were screened retrospectively for eravacycline-resistant Enterobacteriaceae strains, which were further tested for tet(X4) by PCR. The taxonomy of the isolated strains was determined by 16S rRNA gene PCR and Sanger sequencing. RESULTS: Comparative genomic analysis of E. coli 2EC1-1 and 94EC revealed that both carry tet(X4), which is encoded by IncI1-type plasmids p2EC1-1 and p94EC-2, respectively. Retrospective screening of faecal samples collected from 109 healthy individuals showed that the faecal carriage rate of Tet(X4)-producing Enterobacteriaceae is 10.1% (95% CI = 5.1%-17.3%), suggesting that tet(X4) is widely distributed in the gut microbiota of healthy individuals in Singapore. CONCLUSIONS: To the best of our knowledge, this is the first report on the prevalence of tet(X4) in the gut microbiota of a healthy human cohort, as well as the first description of this resistance mechanism outside of China. Our findings suggest that surveillance of tet(X4) in community settings is vital to monitor the spread of this resistance mechanism.

Muribaculum gordoncarteri sp. nov., an anaerobic bacterium from the faeces of C57BL/6J mice.

An anaerobic bacterial strain, named TLL-A4T, was isolated from fecal pellets of conventionally raised C57BL/6J mice. Analysis of the 16S rRNA gene indicated that the strain belongs to the phylum Bacteroidetes and, more specifically, to the recently proposed Muribaculaceae (also known as S24-7 clade or Candidatus Homeothermaceae). Strain TLL-A4T's 16S rRNA gene shared 92.8 % sequence identity with the type strain of the only published species of the genus Muribaculum, Muribaculum intestinale DSM 28989T. Genome-sequencing of TLL-A4T was performed to compare average amino acid identity (AAI) value and percentage of conserved proteins (POCP) between both strains. The AAI analysis revealed that strain TLL-A4T had high identity (69.8 %) with M. intestinale DSM 28989T, while the POCP was 56 %. These values indicate that strain TLL-A4T could be considered a member of the genus Muribaculum but not belonging to the species M. intestinale. Quinone analysis indicated MK10 (63 %) and MK11 (32 %) as major quinones in the membrane, while MK9 was only present as a minor component (5 %). The main cellular fatty acid was anteiso-C15 : 0 (42.8 %); summed feature 11 (17.5 %), C15 : 0 iso (13.4 %), C18 : 1 ω9c (5.6 %), C16.0 3-OH (4.5 %) and C15 : 0 (4.2 %) were detected in minor amounts. Analysis of enzyme activities using the API 32A and API 20A kits indicated major differences between strain TLL-A4T and Muribaculum intestinale DSM 28989T. Based on genotypic, phylogenetic and phenotypic differences, strain TLL-A4T is considered to represent a novel species of the genus Muribaculum, for which the name Muribaculum gordoncarteri sp. nov. is proposed. The type strain is TLL-A4T (=DSM 108194T=KCTC 15770T).

Cultivation and description of Duncaniella dubosii sp. nov., Duncaniella freteri sp. nov. and emended description of the species Duncaniella muris.

Three bacterial strains, C9, H5 and TLL-A3, were isolated from fecal pellets of conventionally raised C57BL/6J mice. Analysis of 16S rRNA genes indicated that the strains belonged to the Muribaculaceae, and shared 91.6-99.9 % sequence identity with the recently described Duncaniella muris DSM 103720T. Genome-sequencing of the isolates was performed to compare average nucleotide identities (ANI) between strains. The ANI analysis revealed that all isolates shared highest ANI with D. muris DSM 103720T, with strain C9 being most similar (ANI: 98.0 %) followed by strains H5 (ANI: 76.4 %) and TLL-A3 (ANI: 74.4 %). Likewise, digital DNA-DNA hybridization (dDDH) indicated high similarity of strain C9 (dDDH: 86.6 %) to D. muris DSM 103720T, but strains H5 and TLL-A3 showed lower similarity (dDDH <35 %) to either of the three type species of the Muribaculaceae (Muribaculum intestinale DSM 28989T , Paramuribaculum intestinale DSM 100749T, D. muris DSM 103720T). MK-10 and MK-11 were abundant in all three isolates, but concentrations varied between species. Based on genotypic, phylogenetic and phenotypic differences, the strains TLL-A3 and H5 are considered to represent novel species of the genus Duncaniella, for which the names Duncaniella freteri sp. nov., and Duncaniella dubosii sp. nov., are proposed. The respective type strains are TLL-A3T (=DSM 108168T=KCTC 15769T), and H5T (=DSM 107170T=KCTC 15734T). Strain C9 reveals limited sequence dissimilarity and minor differences in morphological properties with Duncaniella muris DSM 103720T and is therefore proposed to belong to the same species. The respective strain is C9 (=DSM 107165=KCTC 15733).

Social behaviour and making attachments: a report from the fifth 'Young Microbiologists Symposium on Microbe Signalling, Organisation and Pathogenesis'.

The fifth Young Microbiologists Symposium was held in Queen's University Belfast, Northern Ireland, in late August 2018. The symposium, focused on 'Microbe signalling, organization and pathogenesis', attracted 121 microbiologists from 15 countries. The meeting allowed junior scientists to present their work to a broad audience, and was supported by the European Molecular Biology Organization, the Federation of European Microbiological Societies, the Society of Applied Microbiology, the Biochemical Society and the Microbiology Society. Sessions covered recent advances in areas of microbiology including gene regulation and signalling, secretion and transport across membranes, infection and immunity, and antibiotics and resistance mechanisms. In this Meeting Report, we highlight some of the most significant advances and exciting developments communicated during talks and poster presentations.

Schaedlerella arabinosiphila gen. nov., sp. nov., a D-arabinose-utilizing bacterium isolated from faeces of C57BL/6J mice that is a close relative of Clostridium species ASF 502.

The use of gnotobiotics has attracted wide interest in recent years due to technological advances that have revealed the importance of host-associated microbiomes for host physiology and health. One of the oldest and most important gnotobiotic mouse model, the altered Schaedler flora (ASF) has been used for several decades. ASF comprises eight different bacterial strains, which have been characterized to different extent, but only a few are available through public strain collections. Here, the isolation of a close relative of one of the less-studied ASF strains, Clostridium species ASF 502, from faeces of C57BL/6J mice is reported. Isolate TLL-A1T shares 99.5 % 16S rRNA gene sequence identity with Clostridium species ASF 502 and phylogenetic analyses indicate that both strains belong to the uncultured so-called 'Lachnospiraceae UCG 006' clade. The rare sugar d-arabinose was used as a sole carbon source in the anaerobic isolation medium. Results of growth experiments with TLL-A1T on different carbon sources and analysis of its ~6.5 Gb indicate that TLL-A1T harbours a large gene repertoire that enables it to utilize a variety of carbohydrates for growth. Comparative genome analyses of TLL-A1T and Clostridium species ASF 502 reveal differences in genome content between the two strains, in particular with regards to carbohydrate-activating enzymes. Based on genomic, molecular and phenotypic differences, we propose to classify strain TLL-A1T (DSM 106076T=KCTC 15657T) as a representative of a new genus and a new species, for which we propose the name Schaedlerella arabinosiphila gen. nov., sp. nov.

Effects of teriparatide on morphology of aortic calcification in aged hyperlipidemic mice.

Calcific aortic vasculopathy correlates with bone loss in osteoporosis in an age-independent manner. Prior work suggests that teriparatide, the bone anabolic treatment for postmenopausal osteoporosis, may inhibit the onset of aortic calcification. Whether teriparatide affects the progression of preexisting aortic calcification, widespread among this patient population, is unknown. Female apolipoprotein E-deficient mice were aged for over 1 yr to induce aortic calcification, treated for 4.5 wk with daily injections of control vehicle (PBS), 40 µg/kg teriparatide (PTH40), or 400 µg/kg teriparatide (PTH400), and assayed for aortic calcification by microcomputed tomography (microCT) before and after treatment. In a followup cohort, aged female apolipoprotein E-deficient mice were treated with PBS or PTH400 and assayed for aortic calcification by serial microCT and micropositron emission tomography. In both cohorts, aortic calcification detected by microCT progressed similarly in all groups. Mean aortic 18F-NaF incorporation, detected by serial micropositron emission tomography, increased in the PBS-treated group (+14 ± 5%). In contrast, 18F-NaF incorporation decreased in the PTH400-treated group (-33 ± 20%, P = 0.03). Quantitative histochemical analysis by Alizarin red staining revealed a lower mineral surface area index in the PTH400-treated group compared with the PBS-treated group ( P = 0.04). Furthermore, Masson trichrome staining showed a significant increase in collagen deposition in the left ventricular myocardium of mice that received PTH400 [2.1 ± 0.6% vs. control mice (0.5 ± 0.1%), P = 0.02]. In summary, although teriparatide may not affect the calcium mineral content of aortic calcification, it reduces 18F-NaF uptake in calcified lesions, suggesting the possibility that it may reduce mineral surface area with potential impact on plaque stability. NEW & NOTEWORTHY Parathyroid hormone regulates bone mineralization and may also affect vascular calcification, which is an important issue, given that its active fragment, teriparatide, is widely used for the treatment of osteoporosis. To determine whether teriparatide alters vascular calcification, we imaged aortic calcification in mice treated with teriparatide and control mice. Although teriparatide did not affect the calcium content of cardiovascular deposits, it reduced their fluoride tracer uptake.

In vivo long-term investigation of tumor bearing mKate2 by an in-house fluorescence molecular imaging system.

BACKGROUND: Optical imaging is one of the most common, low-cost imaging tools used for investigating the tumor biological behavior in vivo. This study explores the feasibility and sensitivity of a near infrared fluorescent protein mKate2 for a long-term non-invasive tumor imaging in BALB/c nude mice, by using a low-power optical imaging system. METHODS: In this study, breast cancer cell line MDA-MB-435s expressing mKate2 and MDA-MB-231 expressing a dual reporter gene firefly luciferase (fLuc)-GFP were used as cell models. Tumor cells were implanted in different animal body compartments including subcutaneous, abdominal and deep tissue area and closely monitored in real-time. A simple and low-power optical imaging system was set up to image both fluorescence and bioluminescence in live animals. RESULTS: The presence of malignant tissue was further confirmed by histopathological assay. Considering its lower exposure time and no need of substrate injection, mKate2 is considered a superior choice for subcutaneous imaging compared with fLuc. On the contrary, fLuc has shown to be a better option when monitoring the tumor in a diffusive area such as abdominal cavity. Furthermore, both reporter genes have shown good stability and sensitivity for deep tissue imaging, i.e. tumor within the liver. In addition, fLuc has shown to be an excellent method for detecting tumor cells in the lung. CONCLUSIONS: The combination of mKate2 and fLuc offers a superior choice for long-term non-invasive real-time investigation of tumor biological behavior in vivo.

Light-Sheet Imaging to Elucidate Cardiovascular Injury and Repair.

PURPOSE OF REVIEW: Real-time 3-dimensional (3-D) imaging of cardiovascular injury and regeneration remains challenging. We introduced a multi-scale imaging strategy that uses light-sheet illumination to enable applications of cardiovascular injury and repair in models ranging from zebrafish to rodent hearts. RECENT FINDINGS: Light-sheet imaging enables rapid data acquisition with high spatiotemporal resolution and with minimal photo-bleaching or photo-toxicity. We demonstrated the capacity of this novel light-sheet approach for scanning a region of interest with specific fluorescence contrast, thereby providing axial and temporal resolution at the cellular level without stitching image columns or pivoting illumination beams during one-time imaging. This cutting-edge imaging technique allows for elucidating the differentiation of stem cells in cardiac regeneration, providing an entry point to discover novel micro-circulation phenomenon with clinical significance for injury and repair. These findings demonstrate the multi-scale applications of this novel light-sheet imaging strategy to advance research in cardiovascular development and regeneration.