Second harmonic generation microscopy using pixel reassignment

Second harmonic generation (SHG) microscopy is expected to be a powerful tool for observing the cellular-level functionality and morphology information of thick tissue owe to its unique imaging properties. However, the maximum attainable resolution obtainable by SHG microscopy is limited by the use of long-wavelength, near-infrared excitation. In this paper, we report the use of pixel reassignment to improve the spatial resolution of SHG microscopy. The SHG signal is imaged onto a position-sensitive camera, instead of a point detector typically used in conventional SHG microscope. The data processing is performed through pixel reassignment and subsequent deblurring operation. We present the basic principle and a rigorous theoretical model for SHG microscopy using pixel reassignment (SHG-PR). And for the first time, the optimal reassignment factor for SHG-PR is derived based on the coherent characteristics and the dependence of wavelength in SHG microscopy. To evaluate the spatial resolution improvement, images of nano-beads separated by different distances and of a microtubule array have been simulated. We gain about a 1.5-fold spatial resolution enhancement compared to conventional SHG microscopy. When a further deblurring operation is implemented, this method allows for a total spatial resolution enhancement of about 1.87. Additionally, we demonstrate the validity of SHG-PR for raw data with noise. LAY DESCRIPTION: Second harmonic generation (SHG) microscopy has emerged as a powerful imaging technique in clinical diagnostics and biological research. SHG microscopy is label-free and provides intrinsic optical sectioning for three-dimensional (3D) imaging. However, a near-infrared excitation wavelength results a restriction in the maximum attainable spatial resolution of SHG microscopy. In this paper, we present a simple resolution-enhanced SHG imaging method, SHG microscopy using pixel reassignment (SHG-PR). We demonstrate a rigorous theoretical model for SHG-PR and derive the optimal reassignment factor. The simulation result shows the clear improvement of the image resolution and contrast in the SHG-PR after deblurring operation. The FWHM value of single microtubule shows that SHG-PR enables a spatial resolution enhancement by a factor of 1.5, compared to conventional SHG microscopy. After a proper deblurring operation, this method allows for a total spatial resolution enhancement of about 1.87. The improvements of spatial resolution and contrast are still valid for raw data with noise. It is expected that this method can contribute towards new insights in unstained tissue morphology, interaction of cells, and diseases diagnosis.

[Progress of cohort studies in countries from Asia and Europe]

Objective: To share related knowledge and experiences with countries along the line, literature regarding current cohort studies was summarized. Distribution, establishment and development of cohort studies among large prospective general population were analyzed in 17 countries of Western Asia and the 16 countries of Central and Eastern Europe. Methods: Literature review was conducted to collect basic information on cohort studies, with descriptive study used to analyze the characteristics of these cohort studies. Results: There were 562 cohort studies with sample size as more than 1 000 stated in Western Asia and Central and Eastern Europe, including 468 (83.27%) carried out in the nation itself and 94 (16.73%) with international multicentered collaboration. According to the nature of cohort studies, 347 (61.74%) were etiologically based. As for the contents involved, 310 (55.16%) of them targeted on chronic/non-communicable diseases, 125 (22.24%) concentrated on maternal and child health. Among those on chronic/non-communicable diseases, 51 (16.45%) were on cancers and 83 (26.77%) on cardiovascular disease studies. There appeared 10 large prospective cohort studies targeting on general population, mainly ongoing in Iran and European countries, with a duration of 8-29 years, including 4 of them with sample size as more than 50 000. In terms of the contents, epidemiological investigation, physical examination and biological samples collection took the major parts. Few papers were published in 9 out of the 10 cohort studies at the early stage of those projects but the number of papers increased annually and stabilized to certain extent. Conclusions: The regional distribution of cohort studies carried out in countries from the Western Asia and Central and Eastern European areas appeared unbalanced. Contents of these designs would mainly involve etiological studies, with focus on non-communicable diseases as cancer, cardiovascular disease, diabetes, respiratory diseases, mental and psychological diseases, and maternal and infant health etc.. However, only few large prospective cohort studies would base on general population.

A preliminary study of dual-band confocal laser endomicroscopy combined with image mosaic in the diagnosis of liver cancer

Accurate identification of tumor tissues and their margins are still challenging for conventional clinical imaging methods during liver cancer surgery. In this study, dual-band confocal laser endomicroscopy (CLE) combined with image mosaic was used to guide liver cancer surgery. In the experiments with mice bearing orthotropic liver tumor, CLE can accurately detect the tumors and identify their margins with two excitation wavelengths of 488 nm and 660 nm by clinically available dyes fluorescein sodium (FS) or indocyanine green (ICG). The mosaic CLE images enlarged the imaging field and detected the liver tumor margins more accurately. Normal liver tissues fluorescence intensity of CLE images was significantly higher than that of tumor tissues in the same tumor-bearing mice (P < 0.0001). Overall, dual-band CLE imaging demonstrates to be a promising method to identify liver tumor tissues and margins, which has the prospect of clinical application and helps to achieve intraoperative radical resection.

[Changes of urinary monocyte chemotactic protein 1 and epidermal growth factor and their correlations with clinicopathology in idiopathic membranous nephropathy patients]

Objective: To explore the changes and clinical value of urinary monocyte chemotactic protein 1 (MCP-1), epidermal growth factor (EGF) and their ratio in patients with idiopathic membranous nephropathy (IMN). Methods: A total of 67 IMN patients were enrolled according to kidney biopsy in the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2018. The patients included 28 males and 39 females, with an average age of (47.6±14.2) years. Eighteen age-and sex-matched healthy controls were also enrolled. Clinical and pathological data, blood and urine samples of all subjects were collected. Urinary MCP-1 and EGF level were detected by enzyme-linked immunosorbent assay (ELISA). And then the levels of urinary MCP-1, EGF and the ratio of EGF/MCP-1 and their correlations with clinicopathology were analyzed. Results: There was no statistical difference of the urine EGF levels between the two groups [8.3(6.0,12.6) vs 8.4(6.5,10.2) ng/mg Cr, P=0.575]. The urine MCP-1 levels of IMN patients were 0.37 (0.21, 0.69) ng/mg Cr, which was statistical significantly higher than those of the control group [0.09 (0.02, 0.19) ng/mg Cr] (P<0.001), while the EGF/MCP-1 ratio was lower than that of the control group [22.2(15.1,36.6) vs 87.6(71.2,132.7), P<0.001]. Urine MCP-1 was negatively correlated with eGFR (r=-0.303, P=0.012), but positively correlated with the urinary ratio of albumin to creatinin (r=0.368, P=0.002). EGF was positively correlated with eGFR (r=0.722, P<0.001), but negatively correlated with the severity of interstitial fibrosis and renal tubular atrophy (IFTA) (r=-0.312, P=0.011). EGF/MCP-1 ratio was positively correlated with eGFR (r=0.693, P<0.001), but negatively correlated with the severity of the urinary ratio of albumin to creatinin and IFTA (r=-0.261, P=0.028 and r=-0.684, P<0.001, respectively). Further multivariate logistic regression analysis showed that EGF/MCP-1 was a protective factor for moderate-to-severe IFTA (OR=0.891, 95%CI: 0.844-0.949, P=0.008). Conclusion: Patients with IMN have elevated urine MCP-1 level and decreased EGF/MCP-1 ratio, which correlate with clinical indicators. In particular, EGF/MCP-1 ratio is independently related to moderate-severe IFTA, and may be a potential clinical biomarker for diagnosis of IMN.

Does dual-energy CT differentiate benign and malignant ovarian tumours?

AIM

To assess the ability of dual-energy computed tomography (DECT) to distinguish benign from malignant ovarian tumours (OTs).

MATERIALS AND METHODS

Following approval of the institutional review board, the institutional database was mined for treatment-naive patients who underwent primary cytoreduction for OT. Thirty-seven patients were included and divided into those with benign OTs (n = 11) and malignant OTs (n = 26), including high-grade (n = 20) and low-grade (n = 6) malignant OTs. Advanced processing and region of interest delineation on the ovarian mass were performed using the preoperative staging DECT examination using the Advantage Workstation. The pixel-level data of the CT attenuation values at 50, 70, and 120 keV and the effective atomic number (Z_eff), water content (WC), and iodine content (IC) in the ovarian mass were recorded. The Wilcoxon rank-sum test was used to compare CT attenuation data at different voltages, Z_eff, and WC and IC levels between benign and malignant OTs and between high- and low-grade malignant OTs. Simple logistic regression was used to correlate the imaging characteristics with malignant status and grade.

RESULTS

Malignant OTs had significantly higher Z_eff and IC compared with benign OTs. The threshold values for the diagnosis of malignant OT were IC≥9.74 (100 μg/cm³) with 81% sensitivity and 73% specificity and Z_eff ≥8.16 with 85% sensitivity and 73% specificity. High-grade OTs had significantly higher WC compared with low-grade OTs, and a threshold of ≥1,013.92 mg/cm³ differentiated them with 80% sensitivity and 83% specificity.

CONCLUSION

DECT may be a tool to help distinguish malignant and benign OTs and predict tumour grade.

20-Hydroxyecdysone receptor-activated Bombyx mori CCAAT/enhancer-binding protein gamma regulates the expression of BmCBP and subsequent histone H3 lysine 27 acetylation in Bo. mori

Cyclic adenosine monophosphate (cAMP) response element binding protein (CREB)-binding protein (CBP or CREBBP) plays important roles in regulating gene transcription and animal development. However, the process by which CBP is up-regulated to impact insect development is unknown. In this study, the regulatory mechanism of Bombyx mori CBP (BmCBP) expression induced by 20-hydroxyecdysone (20E) was investigated. In the Bo. mori cell line, DZNU-Bm-12, 20E enhanced BmCBP transcription and histone H3K27 acetylation. BmCBP RNA interference (RNAi) resulted in decreased histone H3K27 acetylation. Additionally, the luciferase activity analysis revealed that the transcription factor, Bo. mori CCAAT/enhancer-binding protein gamma (BmC/EBPg), activated BmCBP transcription, which was suppressed by BmC/EBPg RNAi and promoted by BmC/EBPg overexpression. Electrophoretic mobility shift assay and chromatin immunoprecipitation results demonstrated that BmC/EBPg could bind to the C/EBP cis-regulatory elements in two positions of the BmCBP promoter. Moreover, BmC/EBPg transcription was enhanced by the 20E receptor (BmEcR), which bound to the BmC/EBPg promoter. BmEcR RNAi significantly inhibited the transcriptional levels of BmC/EBPg and BmCBP in the presence of 20E. Furthermore, the BmEcR-BmC/EBPg pathway regulated the acetylation levels of histone H3K27. Altogether, these results indicate that BmEcR enhances the expression of BmC/EBPg, which binds to the BmCBP promoter, activates BmCBP expression and leads to histone H3K27 acetylation.

A novel in vivo Cerenkov luminescence image-guided surgery on primary and metastatic colorectal cancer

Intraoperative Cerenkov luminescence imaging (CLI) can effectively improve the performance of tumor surgery. Nevertheless, the existing approaches are still unsatisfying to the clinical demands of open surgery. This study develops a novel intraoperative in vivo CLI approach to investigate the potential and value of Cerenkov luminescence (CL) image-guided surgery. A system characterized with high sensitivity (19.61 kBq mL^{-1 18} F-FDG) and desirable spatial resolution (88.34 μm) is developed. CL image-guided surgery is performed on colorectal cancer (CRC) models of mice and swine. Tumor surgery is guided by the static CL images, and the resection quality is evaluated quantitatively and contrasted with other imaging modalities exemplified by bioluminescence imaging (BLI). The in vivo results demonstrated the effectiveness of the proposed intraoperative CLI approach for removing primary and metastatic CRC. Safety of performing in vivo CL image-guided surgery is verified as well through radiation measurements of related staffs. Overall, the developed intraoperative in vivo CLI approach can efficiently improve the cancer treatment.

Estimation of error variance via ridge regression

We propose a novel estimator of error variance and establish its asymptotic properties based on ridge regression and random matrix theory. The proposed estimator is valid under both low- and high-dimensional models, and performs well not only in nonsparse cases, but also in sparse ones. The finite-sample performance of the proposed method is assessed through an intensive numerical study, which indicates that the method is promising compared with its competitors in many interesting scenarios.

Determination of Glyphosate and Aminomethylphosphonic Acid in Crops by Capillary Gas Chromatography with Mass-Selective Detection: Collaborative Study

A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.

Correction: S Zheng. Radiological progression of penicillin-sensitive Staphylococcus aureus aortitis

[This corrects the article DOI: 10.12809/hkmj187616].

Surgical repair of traumatic cloaca: a modified technique

AIM

A modified repair technique for traumatic cloaca caused by obstetric anal sphincter injury was evaluated, and its feasibility and functional outcome were investigated.

METHODS

A retrospective review of 23 consecutively enrolled patients diagnosed with traumatic cloaca who underwent the modified repair technique between September 2010 and August 2018 was performed. Demographic, clinical feature, operative and follow-up data were recorded.

RESULTS

The patients diagnosed with traumatic cloaca who underwent surgical repair after obstetric anal sphincter injury had a median time from obstetric injury of 24 (12-35) years. The median preoperative Wexner faecal incontinence score was 16 (14-17). The postoperative hospital stay was 6 (6-7) days. The median postoperative Wexner faecal incontinence score decreased to 2 (2-3). The anal resting pressure increased from 9.00 (5.25-11.50) mmHg to 56.00 (55.00-65.75) mmHg (P < 0.01) and the anal squeeze pressure increased from 29.00 (22.50-33.20) mmHg to 110.00 (96.20-121.50) mmHg (P < 0.01) at 2 months after the repair. Sixteen patients completed the Faecal Incontinence Quality of Life Scale questionnaire, and there were significant improvements 1 year after surgical repair in lifestyle (3.10 [2.60-3.70] vs 2.60 [1.90-3.00], P < 0.01), coping/behaviour (3.38 [2.57-3.44] vs 2.33 [1.89-3.00], P < 0.01), depression/self-perception (3.11 [2.27-3.44] vs 2.33 [1.89-3.00], P < 0.01) and embarrassment (3.33 [2.75-3.67] vs 2.33 [2.33-3.00], P < 0.01). No patient presented rectovaginal fistula postoperatively within the median follow-up period of 24 (12-48) months.

CONCLUSIONS

The modified repair technique for traumatic cloaca is feasible and achieves good functional outcomes and improved life quality.

miR-183-5p enhances the radioresistance of colorectal cancer by directly targeting ATG5

Radioresistance is a material obstacle for effective treatment of colorectal cancer (CRC). Thus, the discovery of a novel biomarker for determining the CRC radiosensitivity is necessary. Recent studies have confirmed that miR-183-3p regulates cell phenotypes and tumor growth in various cancers. However, the role and mechanism of this micro-ribonucleic acid in CRC radiosensitivity remains unclear. Here, the abundances of miR-183-5p and ATG5 mRNAwere detected by a real-time quantitative reverse transcription polymerase chain reaction. Kaplan-Meier survival analysis was carried out to explore the correlation between miR-183-5p and patient prognosis. Cell viability was evaluated by the MTT assay. Survival fraction analysis through colony formation was performed to assess the cell radiation response. Bioinformatic, luciferase and western blot assays were employed to verify the targeted interaction between miR-183-5p and ATG5. The results showed that an elevated abundance of miR-183-5p and a reduced ATG5 level in CRC were associated with the poor prognosis. The knockdown of miR-183-5p enhanced the sensitivity of CRC cells to radiation, inflected by the decreased cell viability and survival fraction. Mechanically, ATG5 was targeted by miR-183-5p. The addition of ATG5 conferred the radiosensitivity of the CRC cells, which was revered by miR-183-5p restoration. Furthermore, miR-183-5p knockdown hindered the tumor growth by repressing ATG5 in vivo after radiation treatment. In summary, the output data indicated that miR-183-5p heightened the radiation response of the CRC cells by targeting ATG5, promising a novel therapeutic target for CRC patients with radioresistance.

Downregulation of microRNA-214 improves therapeutic potential of allogeneic bone marrow-derived mesenchymal stem cell by targeting PIM-1 in rats with acute liver failure

Acute liver failure (ALF) is a disease resulted from diverse etiology, which generally leads to a rapid degenerated hepatic function. However, transplantation bone marrow-derived mesenchymal stem cells (BMSCs) transplantation has been suggested to relieve ALF. Interestingly, microRNA-214 (miR-214) could potentially regulate differentiation and migration of BMSCs. The present study aims to inquire whether miR-214 affects therapeutic potential of BMSCs transplantation by targeting PIM-1 in ALF. 120 male Wistar rats were induced as ALF model rats and transplanted with BMSCs post-alteration of miR-214 or PIM-1 expression. Further experiments were performed to detect biochemical index (alanine aminotransferase [ALT], aspartate transaminase [AST], total bilirubin [TBiL]), and expression of miR-214, PIM-1, hepatocyte growth factor (HGF), caspase 3, tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) in rat serum. Apart from the above detection, apoptosis of hepatocytes and Ki67 protein expression in hepatic tissues of rats were additionally assessed. After BMSCs transplantation with miR-214 inhibition, a decreased expression of ALT, AST, and TBiL yet an increased expression of HGF was shown, coupled with a decline in the expression of caspase 3, TNF-α, and IL-10. Meanwhile, alleviated hepatic injury and decreased apoptotic index of hepatic cells were observed and the positive rate of Ki67 protein expression was significantly increased. Moreover, miR-214 and caspase 3, TNF-α, and IL-10 decreased notably, while PIM-1 was upregulated in response to miR-214 inhibition. Strikingly, the inhibition of PIM-1 reversed effects triggered by miR-214 inhibition. These findings indicated that downregulation of miR-214 improves therapeutic potential of BMSCs transplantation by upregulating PIM-1 for ALF.

Radiopharmaceuticals and Fluorescein Sodium Mediated Triple-Modality Molecular Imaging Allows Precise Image-Guided Tumor Surgery

Radical resection is the most effective method for malignant tumor treatments. However, conventional imaging cannot fully satisfy the clinical needs of surgical navigation. This study presents a novel triple-modality positron emission tomography (PET)-Cerenkov radiation energy transfer (CRET)-confocal laser endomicroscopy (CLE) imaging strategy for intraoperative tumor imaging and surgical navigation. Using clinical radiopharmaceuticals and fluorescein sodium (FS), this strategy can accurately detect the tumor and guide the tumor surgery. The FS emission property under Cerenkov radiation excitation is investigated using 2-deoxy-2-18F-fluoroglucose and 11C-choline. Performances of the PET-CRET-CLE imaging and the CRET-CLE image-guided surgery are evaluated on mouse models. The CRET signal at 8 mm depth is stronger than the Cerenkov luminescence at 1 mm depth in phantoms. In vivo experiments indicate that 0.5 mL kg-1 of 10% FS generates the strongest CRET signal, which can be observed immediately after FS injection. A surgical navigation study shows that the tumors are precisely detected and resected using intraoperative CRET-CLE. In summary, a PET-CRET-CLE triple-modality imaging strategy is developed. This strategy can detect the tumors and precisely guide the tumor resection using clinical pharmaceuticals. This triple-modality imaging shows high potential in surgical navigation research and clinical translation.

Effects of salt and drought stresses on antioxidant system and RbohC and RbohF genes expression in Brassica campestris

To investigate the effects of salt stress and PEG-6000 simulating drought stress on the active oxygen and antioxidant enzyme activities, as well as the expression level of RbohC and RbohF genes, the seedlings of two Brassica campestris, Longyou 6 and Tianyou 2, were treated with U0126 (a MAPKK inhibitor), DMTU (a H₂O₂ scavenger), as well as DPI and IMD (NADPH oxidase inhibitors). The results showed that under both stresses, H₂O₂ accumulation as well as antioxidant enzyme (SOD, CAT, APX, GR) activities and the expression of RbohC and RbohF genes increased, while O₂^-· accumulation decreased. The O₂^-· accumulation, antioxidant enzyme activity and RbohC and RbohF genes expression in both varieties all significantly decreased. Compared to seedlings with on pretreatment before salt and PEG-6000 simulating drought stress, the accumulation of H₂O₂ decreased in seedlings pretreated with DMTU, DPI and IMD. However, the accumulation of H₂O₂ increased in those pretreated with U0126. Those results indicated that the NADPH oxidase, MAP kinase cascade and H₂O₂ were involved in the regulation of active oxygen production and antioxidant enzyme activity, as well as the expression of RbohC and RbohF under salt stress and drought stress.