Investigating HMGB1 as a potential serum biomarker for early diabetic nephropathy monitoring by quantitative proteomics

Current diagnostic methods for diabetic nephropathy (DN) lack precision, especially in early stages and monitoring progression. This study aims to find potential biomarkers for DN progression and evaluate their accuracy. Using serum samples from healthy controls (NC), diabetic patients (DM), early-medium stage DN (DN-EM), and late-stage DN (DN-L), researchers employed quantitative proteomics and Mfuzz clustering analysis revealed 15 proteins showing increased expression during DN progression, hinting at their biomarker potential. Combining Mfuzz clustering with weighted gene co-expression network analysis (WGCNA) highlighted five candidates (HMGB1, CD44, FBLN1, PTPRG, and ADAMTSL4). HMGB1 emerged as a promising biomarker, closely correlated with renal function changes. Experimental validation supported HMGB1's upregulation under high glucose conditions, reinforcing its potential as an early detection biomarker for DN. This research advances DN understanding and identifies five potential biomarkers, notably HMGB1, as a promising early monitoring target. These findings set the stage for future clinical diagnostic applications in DN.

A novel miniature flexible robotic system for endoscopic mucosal dissection: an animal experimental study

Endoscopic submucosal dissection (ESD) is a standard treatment for early gastrointestinal cancer due to its higher rate of en-bloc resection and lower recurrence rate. However, the technical challenges lead to long learning curve and high risks of adverse events. A gastrointestinal flexible robotic-tool system (GIFTS) was proposed to reduce the difficulty and shorten the learning curve of novices. This is an animal study to evaluate the feasibility of GIFTS in ESD. The GIFTS provides a total of 13 degrees of freedom within 10 mm in diameter and variable stiffness function to achieve endoscopic intervention and submucosal dissection with the cooperation of two flexible robotic instruments. One esophageal and four colorectal ESDs in five porcine models were performed. In all five ESD procedures, the GIFTS was successfully intubated and submucosal dissection was completed without perforation or significant bleeding, and there was no system fault. The mean operative time was 99 min, and the mean size of the specimen was 151 mm2. The fifth experiment showed significantly better results than the first one. In vivo animal experiments confirmed the feasibility of GIFTS in performing ESD. The control of GIFTS is friendly to inexperienced beginners, which will help reduce the technical challenges of ESD and shorten the learning curve of endoscopists.

Flexible instrument with contact-aided structure and force feedback for endoscopic surgery

BACKGROUND

Robot-assisted surgery can effectively reduce the difficulty and improve the success rate of the surgeries. However, currently available flexible instruments have several limitations, such as large size, few degrees of freedom, and lack of contact force perception.

METHODS

This study proposes a master-slave flexible instrument capable of force feedback. The instrument has a maximum outer diameter of 3 mm and an overall length of 1200 mm. With the internal working channel unoccupied, a three-dimensional force sensing unit is designed based on the neural network. The corresponding master-slave control method with proportional force feedback was also designed to effectively control the instrument.

RESULTS

To verify the effectiveness of the system, in vitro and in vivo experiments were conducted. The corresponding tasks were successfully completed.

CONCLUSIONS

The animal trial conducted in the digestive tract of a live swine proved that the system has the potential for clinical use.

Flexible endoscopic instrument for diagnosis and treatment of early gastric cancer

Gastric cancer is a common cancer endangering human life and health worldwide. Early detection and diagnosis of gastric cancer that is normally performed by flexible endoscope can significantly improve the survival rate of patients. However, current endoscopic instruments have some problems, such as limitation of degrees of freedom (DOFs) and lack of surgical triangulation. Meanwhile, the lack of an intraoperative technique for the real-time evaluation of early gastric cancer is also a serious problem. To solve these problems, we have developed a dual-bending flexible endoscopic instrument for the diagnosis and treatment of early gastric cancer. This instrument has a compact structure with a maximum outer diameter of 3 mm and an insertion length of 1220 mm. It has 5 DOFs with a dual-bending function, which can form a surgical operation triangulation to easily perform the endoscopic procedure. Apart from the surgical forceps, the end of the instrument can be equipped with different endoscopic devices to meet the needs of diagnosis and treatment, such as endomicroscopic probes, electrosurgical knives, and laser ablation optical fibers. It is verified that the instrument can carry these devices to complete corresponding tasks, demonstrating the great potential of this instrument in clinical applications.

Pharmacological inhibition of SMYD2 protects against cisplatin-induced renal fibrosis and inflammation

SET and MYND domain protein 2 (SMYD2) can methylate histone H3 at lysine36 (H3K36) and some non-histone substrates to play a role in tumorigenesis. However, It is unclear how SMYD2 contributes to chronic kidney disease (CKD). Here, AZ505 or LLY507, which could inhibit SMYD2, were used in cisplatin-induced CKD to investigate the effects and possible mechanisms by which they might act. We found that high expression of SMYD2 in cisplatin-induced CKD. However, AZ505 or LLY507 can significantly inhibit its expression, improve renal function injury and fibrosis induced by cisplatin, inhibit the transition of epithelial cells to a fibrogenic phenotype and fibrosis-related proteins, inhibit the expression of Inflammatory Cytokines (such as IL-6 and TNF-α), And inhibit the phosphorylation of pro-fibrosis molecule Smad3 and signal transduction and transcription activator-3 (STAT3) and up-regulated the expression of renal protective factor Smad7. In cultured tubular epithelial cells, AZ505 also can inhibit the expression of EMT, fibrosis-related proteins, and inflammatory cytokines in cisplatin-induced tubular epithelial cells. Based on these findings, SMYD2 may be a critical regulator of cisplatin-induced CKD and targeted pharmacological inhibition of SMYD2 may prevent cisplatin-induced CKD through Smad3 or STAT3-related signaling pathways.

Self-supervised monocular depth estimation for gastrointestinal endoscopy

BACKGROUND AND OBJECTIVE

Gastrointestinal (GI) endoscopy represents a promising tool for GI cancer screening. However, the limited field of view and uneven skills of endoscopists make it remains difficult to accurately identify polyps and follow up on precancerous lesions under endoscopy. Estimating depth from GI endoscopic sequences is essential for a series of AI-assisted surgical techniques. Nonetheless, depth estimation algorithm of GI endoscopy is a challenging task due to the particularity of the environment and the limitation of datasets. In this paper, we propose a self-supervised monocular depth estimation method for GI endoscopy.

METHODS

A depth estimation network and a camera ego-motion estimation network are firstly constructed to obtain the depth information and pose information of the sequence respectively, and then the model is enabled to perform self-supervised training by calculating the multi-scale structural similarity with L1 norm (MS-SSIM+L1) loss function between the target frame and the reconstructed image as part of the loss of the training network. The MS-SSIM+L1 loss function is good for reserving high-frequency information and can maintain the invariance of brightness and color. Our model consists of the U-shape convolutional network with the dual-attention mechanism, which is beneficial to capture muti-scale contextual information, and greatly improves the accuracy of depth estimation. We evaluated our method qualitatively and quantitatively with different state-of-the-art methods.

RESULTS AND CONCLUSIONS

The experimental results manifest that our method has superior generality, achieving lower error metrics and higher accuracy metrics on both the UCL dataset and the Endoslam dataset. The proposed method has also been validated with clinical GI endoscopy, demonstrating the potential clinical value of the model.

A monocular SLAM system based on SIFT features for gastroscope tracking

During flexible gastroscopy, physicians have extreme difficulties to self-localize. Camera tracking method such as simultaneous localization and mapping (SLAM) has become a research hotspot in recent years, allowing tracking of the endoscope. However, most of the existing solutions have focused on tasks in which sufficient texture information is available, such as laparoscope tracking, and cannot be applied to gastroscope tracking since gastroscopic images have fewer textures than laparoscopic images. This paper proposes a new monocular SLAM framework based on scale-invariant feature transform (SIFT) and narrow-band imaging (NBI), which extracts SIFT features instead of oriented features from accelerated segment test (FAST) and rotated binary robust independent elementary features (BRIEF) features from gastroscopic NBI images, and performs feature retention based on the response sorting strategy for achieving more matches. Experimental results show that the root mean squared error of the proposed algorithm can reach a minimum of 2.074 mm, and the pose accuracy can be improved by up to 25.73% compared with oriented FAST and rotated BRIEF (ORB)-SLAM. SIFT features and response sorting strategy can achieve more accurate matching in gastroscopic NBI images than other features and homogenization strategy, and the proposed algorithm can also run successfully on real clinical gastroscopic data. The proposed algorithm has the potential clinical value to assist physicians in locating the gastroscope during gastroscopy.

[The timing of pericardial drainage catheter removal and restart of the anticoagulation in patients suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran: Experiences from 20 cases]

Objective: To investigate the timing of pericardial drainage catheter removal and restart of the anticoagulation in patients with atrial fibrillation (AF) suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran. Methods: A total of 20 patients with pericardial tamponade, who underwent AF catheter ablation with uninterrupted dabigatran in Beijing Anzhen Hospital from January 2019 to August 2021, were included in this retrospective analysis. The clinical characteristics of enrolled patients, information of catheter ablation procedures, pericardial tamponade management, perioperative complications, the timing of pericardial drainage catheter removal and restart of anticoagulation were analyzed. Results: All patients underwent pericardiocentesis and pericardial effusion drainage was successful in all patients. The average drainage volume was (427.8±527.4) ml. Seven cases were treated with idarucizumab, of which 1 patient received surgical repair. The average timing of pericardial drainage catheter removal and restart of anticoagulation in 19 patients without surgical repair was (1.4±0.7) and (0.8±0.4) days, respectively. No new bleeding, embolism and death were reported during hospitalization and within 30 days following hospital discharge. Time of removal of pericardial drainage catheter, restart of anticoagulation and hospital stay were similar between patients treated with idarucizumab or not. Conclusion: It is safe and reasonable to remove pericardial drainage catheter and restart anticoagulation as soon as possible during catheter ablation of atrial fibrillation with uninterrupted dabigatran independent of the idarucizumab use or not in case of confirmed hemostasis.

Actuation and design innovations in earthworm-inspired soft robots: A review

Currently, soft robotics technologies are creating the means of robotic abilities and are required for the development of biomimetic robotics. In recent years, earthworm-inspired soft robot has garnered increasing attention as a major branch of bionic robots. The major studies on earthworm-inspired soft robots focuses on the deformation of the earthworm body segment. Consequently, various actuation methods have been proposed to conduct the expansion and contraction of the robot's segments for locomotion simulation. This review article aims to act as a reference guide for researchers interested in the field of earthworm-inspired soft robot, and to present the current state of research, summarize current design innovations, compare the advantages and disadvantages of different actuation methods with the purpose of inspiring future innovative orientations for researchers. Herein, earthworm-inspired soft robots are classified into single- and multi-segment types, and the characteristics of various actuation methods are introduced and compared according to the number of matching segments. Moreover, various promising application instances of the different actuation methods are detailed along with their main features. Finally, motion performances of the robots are compared by two normalized metrics-speed compared by body length and speed compared by body diameter, and future developments in this research direction are presented.

Ranunculus ternatus Thunb extract attenuates renal fibrosis of diabetic nephropathy via inhibiting SMYD2

CONTEXT

Ranunculus ternatus Thunb (Ranunculaceae), (RTT) is used clinically for the treatment of tuberculosis or as tumour adjuvant therapy, but its potential effect on diabetic nephropathy (DN) has not been studied.

OBJECTIVE

To investigate the effect of RTT extract in renal fibrosis of DN.

MATERIALS AND METHODS

C57BL/6 mice were randomly divided into four groups (n = 12). Diabetes mellitus (DM) mice were induced by streptozotocin (STZ, 55 mg/kg/day) for five consecutive days and treated by RTT extract (2 g/kg). Afterward, blood glucose, HE and Masson staining were assayed. The expression levels of Vimentin, ɑ-SMA, TNF-ɑ, NF-κB p-p65, NF-κB p65, SMYD2, H3K36me3, H3K4me3 were determined by western blots. Firbronectin was respectively assayed by western blot and immunofluorescent staining.

RESULTS

RTT extract significantly ameliorated renal injury and renal fibrosis in the renal tissue of STZ-induced diabetic mice as demonstrated by the decreased expression level of Fibronectin (65%), Vimentin and α-SMA (75% & 53%). In addition, the levels of TNF-α (57%), NF-κB p-p65 and NF-κB p65 (35% & 25%) were elevated in the DN mice. Importantly, these were alleviated after RTT extract treatment. Moreover, we observed that the protein levels of SMYD2 (30%), H3K36me3 and H3K4me3 (53% & 75%) were reduced in DN mice after treatment with RTT extract.

DISCUSSION AND CONCLUSIONS

RTT extract mediates antifibrotic effects and anti-inflammatory responses in STZ-induced DN mainly through suppressing SMYD2 activation and H3K36me3 and H3K4me3 protein expression. RTT extract might have therapeutic potential against high glucose-induced nephropathy.

[Confocal probe localization algorithm based on region growing and endoscope size prior]

Confocal laser endomicroscopy technology can obtain cell-level images in real time and in situ, which can assist doctors in real-time intraoperative diagnosis, but its non-invasiveness makes it difficult to relocate the optical biopsy site. The confocal probe localization algorithm can automatically calculate the coordinates of the probe tip, that is, the coordinates of the optical biopsy site. In this paper, a confocal probe localization algorithm based on region growing and endoscope size prior was proposed. The algorithm detected the probe region by region growing on the probe edge image, then searched for tip points based on a given probe axis, and iteratively optimized it. Finally, based on the single-degree-of-freedom motion characteristics of the probe, the three-dimensional coordinates of the tip of the probe were calculated by using the prior information of the size of the endoscope, which solved the scale uncertainty problem of the monocular camera. The confocal probe localization algorithm was tested on the dataset collected in this paper. The results showed that our algorithm no longer relied on the color information of the probe, avoided the influence of uneven illumination on the gray value of the probe pixels, and had a more robust location accuracy and running speed. Within the length of the probe extending out of the endoscope from 0 to 5 cm, the pixel error could be as low as 11.76 pixels, and the average relative position error could be as low as 1.66 mm, which can achieve the real-time and accurate localization of the confocal probe.

[The relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation]

Objective: To explore the relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation (NVAF). Methods: This was an observational study based on data from a multicenter, prospective Chinese atrial fibrillation registry cohort, which included 18 703 consecutive patients with atrial fibrillation (AF) in 31 hospitals in Beijing from August 2011 to December 2018. Patients were divided into 5 groups according to status of comorbid diabetes and fasting glucose levels at admission: normal blood glucose (normal glucose group), pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group. Patients were followed up by telephone or outpatient service every 6 months. The primary follow-up endpoint was thromboembolic events, including ischemic stroke and systemic embolism. The secondary endpoint was the composite endpoint of cardiovascular death and thromboembolic events. Kaplan-Meier survival analysis and multifactorial Cox regression were used to analyze the correlation between fasting glucose levels and endpoint events. Results: The age of 18 703 patients with NVAF was (63.8±12.0) years, and there were 11 503 (61.5%) male patients. There were 11 877 patients (63.5%) in normal blood glucose group, 2 023 patients (10.8%)in pre-diabetes group, 1 131 patients (6.0%) in strict glycemic control group, 811 patients in average glycemic control group and 2 861 patients(4.3%) in poor glycemic control group. Of the 4 803 diabetic patients, 1 131 patients (23.5%) achieved strict glycemic control, of whom 328 (29.0%) were hypoglycemic (fasting blood glucose level<4.4 mmol/L at admission). During a mean follow-up of (51±23) months (up to 82 months), thromboembolic events were reported in 984 patients (5.3%). The survival curve analysis of Kaplan Meier showed that the incidence rates of thromboembolic events in normal glucose group, pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group were 1.10/100, 1.41/100, 2.09/100, 1.46/100 and 1.71/100 person-years, respectively (χ²=53.0, log-rank P<0.001). The incidence rates of composite endpoint events were 1.86/100, 2.17/100, 4.08/100, 2.58/100, 3.16/100 person-years (χ²=72.3, log-rank P<0.001). The incidence of thromboembolic events and composite endpoint events in the other four groups were higher than that in the normal blood glucose group (P<0.001). Multivariate Cox regression analysis showed that compared with normal glucose group, the risk of thromboembolism increased in pre-diabetes group(HR=1.23, 95%CI 1.00-1.51, P=0.049), strict glycemic control group(HR=1.32, 95%CI 1.06-1.65, P=0.013) and poor glycemic control group(HR=1.26, 95%CI 1.01-1.58, P=0.044). Conclusion: Both high or low fasting glucose may be an independent risk factor for thromboembolic events in patients with NVAF.

[Clinical analysis of 554 patients with colorectal diverticulosis]

Objective: Most patients with asymptomatic colorectal diverticulosis are easily overlooked. However, some of diverticulosis become diverticulitis, bleeding and even perforation, which cause extensive harm to patients. The purpose of this study is to analyze the incidence, clinical features, diagnosis and treatment of colorectal diverticulosis in order to improve the clinical understanding of diverticulosis and its related complications. Methods: A descriptive cohort study was carried out. Clinical data of 554 patients with colorectal diverticulosis confirmed by CT, colonoscopy, digestive tract radiography or operation in Peking University First Hospital from January 2009 to June 2019 were retrospectively analyzed. Patients with malignant tumors, autoimmune diseases, long term use of immunosuppressive drugs, chronic liver diseases and renal diseases, and mental disorders were excluded. The analysis parameters included gender, onset age, clinical symptoms, location of diverticulitis, treatment and prognosis. According to the criteria established by the World Society of Emergency Surgery (WSES), acute diverticulitis was divided into 5 stages based on the extension of the infectious process. Stage 0 was simple diverticulitis and stage 1-4 was complicated diverticulitis. Results: Among the 554 patients with colorectal diverticulosis, 358 (64.6%) were males, the median onset age was 63 years; 191 patients (34.5%) had various digestive symptoms, of whom 113 (20.4%) had chronic constipation and abdominal distension, 78 (14.1%) had chronic diarrhea and abdominal pain; the other 363 patients had no obvious abdominal symptoms. Four hundred and six patients were found by colonoscopy and 465 patients were found by CT. Twenty-five patients were diagnosed by lower gastrointestinal tract radiography and 3 were confirmed during operation. There were 339 patients with multiple diverticula (61.2%) and 215 patients with single diverticulum (38.8%). 76.5% (424/554) of diverticula were located in colon, 37.0% (205/554) in ascending colon, 21.3% (118/554) in multiple sites, and 2.2% (12/554) in rectum. The median diameter of diverticulum was 7 mm, and 78 cases (14.1%) was ≥30 mm. Forty-nine patients (8.8%) developed acute diverticulitis, including 13 patients with simple diverticulitis and 36 patients with complicated diverticulitis. Among 36 patients with complicated diverticulitis, 29 (80.6%) were males, 27 (75.0%) had recurrent abdominal pain and fever before onset; diverticula of 25 cases were located in sigmoid colon; 11 cases in ascending colon. Nine cases developed sigmoid colon perforation and 8 cases developed vesicocolonic fistula, and these 17 patients underwent surgical treatment. The other 19 cases with complicated diverticulitis developed gastrointestinal bleeding, of whom 18 cases were male, 11 cases were located in ascending colon; 13 cases were healed after conservative treatment, 4 cases received endoscopic hemostatic intervention, and 2 cases underwent surgery. Conclusions: Colorectal diverticulosis is more common in male patients, and CT and colonoscopy are main diagnostic methods. The symptoms of complicated colonic diverticulitis are related to the location of diverticulum. In addition to symptomatic treatment, surgical procedures are the most important treatments.

[Thirty years' changes of the strategy of lateral lymph node dissection in low rectal cancer: treatment experience and prognostic analysis of 289 cases in one single center]

Objective: The surgical indications, resection extent and management principle of lateral lymph node dissection (LLND) in lower rectal cancer have been controversial between Eastern and Western countries. This study aims to provide a theoretical basis for the rational implementation of LLND by reviewing the changes of LLND strategy over the past 30 years in a single-center, and analyzing prognostic factors for the survival outcomes of patients with lateral lymph node metastasis (LLNM). Methods: A retrospective observational study was performed. Clinical data of 289 patients with rectal cancer who received LLND at the Department of General Surgery of Peking University First Hospital from 1990 to 2019 were collected. Patients were divided into three groups based on decades. There were 89 cases in 1990-1999 group, 92 cases in the 2000-2009 group, and 108 cases in the 2010-2019 group. Data analyzed: (1) patient baseline data; (2) surgery and postoperative recovery; (3) lateral lymph node dissection; (4) postoperative survival and prognosis of patients with positive lateral lymph nodes. The surgical methods and pathological results of LLND were compared between groups, and the prognostic risk factors of patients with LLNM were analyzed. Results: A total of 289 patients underwent radical resection with LLND' accounting for 6.3% of the 4542 patients with rectal cancer during the same period in our hospital. Except decade-by-decade increase in tumors with distance from anal verge ≤ 7 cm, the proportion of ulcerated tumors, and the proportion of neoadjuvant radiochemotherapy, the differences in other baseline data were not statistically significant among 3 decade groups (all P>0.05). The proportion of LLND in the 3 groups decreased decade by decade [9.9% (89/898) vs. 8.0% (92/1154) vs. 4.3% (108/2490), χ(2)=40.159, P<0.001]. The proportion of laparoscopic surgery and unilateral LLND increased, while the mean operative time, intraoperative blood loss, surgical complications above grade III and postoperative hospital stay decreased decade by decade. These 289 patients completed a total of 483 lateral dissections, including 95 cases of the unilateral dissection and 194 cases of the bilateral dissection. The proportion of LLND in the 3 groups decreased decade by decade [9.9% (89/898) vs. 8.0% (92/1154) vs. 4.3% (108/2510), P<0.001]. The median number of dissected lymph nodes in the internal iliac artery and obturator regions increased (2 vs. 3 vs. 3, P<0.001), but those in the common iliac and external iliac regions decreased significantly (4 vs. 3 vs. 2, P=0.014). A total of 71 patients with LLNM were identified. The rate of LLNM in the 2010-2019 group was significantly higher than that in the previous two groups [37.0% (40/108) vs. 16.9% (15/89) vs. 17.4% (16/92), P=0.001]. The patients with LLNM showed a poorer overall survival (OS) and disease-free survival (DFS) compared with negative lateral lymph nodes (P<0.001). There were statistically significant differences in 5-year OS rate (30.9% vs. 27.2% vs. 0, P=0.028) and 5-year DFS rate (28.3% vs. 16.0% vs. 0, P=0.038) among patients with only internal iliac lymph node metastasis, patients with only obturator lymph node metastasis, and patients with external iliac or common iliac lymph node metastasis. Multivariate analysis of prognostic factors showed that external iliac or common iliac lymph node metastasis was an independent risk factor for OS (HR=1.649, 95%CI: 1.087-2.501) and DFS (HR=1.714, 95%CI: 1.173-2.504) in patients with LLNM (all P<0.05) . The OS and DFS were not significant different in patients with LLNM among 3 decade groups. Conclusions: In the past decade, the proportion of LLND in rectal cancer has decreased significantly. However, LLNM rate has been significantly increased due to preoperative imaging assessments focusing on suspicious LLNM without compromising the survival. Internal iliac artery and obturator lymph nodes can be regarded as regional lymph nodes with a satisfactory prognosis after LLND. For suspected external iliac or common iliac lymph node metastasis, the significance of LLND remains to be further evaluated.

Design of Low-Cost Endoscope Based on Novel Wire-Driven Rotary Valve and Water-Jet Mechanism

To improve the prevalence of screening for gastric cancer in low-income areas, a low-cost endoscope based on a novel wire-driven rotary valve and water-jet mechanism is proposed. The primary component of this endoscope is a rotary valve whose core is driven by a stepper motor through a flexible wire, which controls the direction of the water jet. This enables it to reach any point in the workspace by controlling the valve core angle and water-jet intensity. The envelope surface of the endoscope tip trajectory is likely a hemisphere. The horizontal diameter of the working space projection is approximately 350 mm, which is sufficient to observe most parts of the greater curvature of the stomach. The image-acquisition performance of the designed endoscope was satisfactory in a phantom experiment. The introduction of the novel rotary valve greatly simplifies the structure and reduces the cost of the proposed endoscope. With low cost and high portability, this endoscope provides a good alternative for early gastric cancer screening in low- and middle-income areas.

[Design, screening and antibacterial activity evaluation of the novel antibacterial peptide KR-1]

OBJECTIVE

To design novel antimicrobial peptides with high activity and low toxicity and evaluate their effect against Streptococcus mutans and other oral bacteria for prevention and treatment of dental caries.

OBJECTIVE

We synthesized two antimicrobial peptides (KR-1 and KR-2) using Dhvar4 (a histatins5 mimic) as the template. The antimicrobial peptides with high activity and low toxicity were screened using minimal inhibitory concentration (MIC) test, hemolysis test, and CCK-8 assay. Streptococcus mutans biofilms cultured in 96-well plates were divided into experimental group (KR-1) and positive control group (CHX) and treated with concentration gradients (0.6×, 0.8×, 1× and 2× MICs) of KR-1 and CHX, respectively. Crystal violet staining was used for quantitative analysis of the changes of the biofilms after the treatments. The structural changes of the biofilms were observed with laser confocal microscopy after KR-1 treatment at 10 × MIC. The antimicrobial activity of KR-1 against oral Streptococcus was analyzed based on the time required for sterilization after KR-1 treatment.

OBJECTIVE

The MIC of KR-1 and KR-2 for S. mutans was 3.2 μmol/L and 12.8 μmol/L, respectively. Under the effective concentration, KR-1 and KR-2 resulted in hemolysis rates of 0.35% and 48.8% in rabbit red blood cells and lowered the survival rates of gingival fibroblasts to 88.7% and 21.94%, respectively. KR-1 treatment significantly reduced biofilm formation with a minimum biofilm inhibition concentration (MBIC₅₀) lower than 1.92 μmol/L, and showed an even stronger antimicrobial than CHX at the concentration of 2.56 μmol/L (P=0.001). Confocal laser scanning microscopy revealed that the biofilm structure became loosened after KR-1 treatment, which was capable of killing about 90% of the bacteria within 5 min.

OBJECTIVE

The antimicrobial peptide KR-1 has a stronger antibacterial activity and a low toxicity with a good inhibitory effect against S. mutans biofilm.

Flexible Manipulator with Low-Melting-Point Alloy Actuation and Variable Stiffness

Flexible manipulators offer significant advantages over traditional rigid manipulators in minimally invasive surgery, because they can flexibly navigate around obstacles and pass cramped or tortuous paths. However, due to the inherent low stiffness, the ability to control/obtain higher stiffness when required remains to be further explored. In this article, we propose a flexible manipulator that exploits the phase transformation property of low-melting-point alloy to hydraulically drive and change the stiffness by heating and cooling. A prototype was fabricated, and experiments were conducted to evaluate the motion characteristics, stiffness performance, and rigid-flexible transition efficiency. The experimental results demonstrate that the proposed manipulator can freely adjust heading direction in the three-dimensional space. The experimental results also indicate that it took 9.2-10.3 s for the manipulator to transform from a rigid state to a flexible state and 15.4 s to transform from a flexible state to a rigid state. The lateral stiffness and flexural stiffness of the manipulator were 95.54 and 372.1 Ncm² in the rigid state and 7.26 and 0.78 Ncm² in the flexible state. The gain of the lateral stiffness and flexural stiffness was 13.15 and 477.05, respectively. In the rigid state, the ultimate force without shape deformation was more than 0.98 N in the straight condition (0°) and 1.36 N in the bending condition (90°). By assembling flexible surgical tools, the manipulator can enrich the diagnosis or treatment functions, which demonstrated the potential clinical value of the proposed manipulator.

A novel master-slave intraocular surgical robot with force feedback

BACKGROUND

Intraocular surgery is one of the most challenging microsurgeries. Unintended movements of human hand and lack of force feedback can seriously affect surgical safety.

METHODS

We developed a novel master-slave robotic system with force feedback to assist intraocular surgeries. Isomorphism design was adopted to achieve intuitive control of the system. Contact force between instrument tip and tissues was measured with a force sensor developed by our group. Real-time force feedback was provided with one linear voice coil motor and two magnetic particle brakes in the master manipulator.

RESULTS

Experiments were carried out to verify the proposed system. In the phantom experiment mimicking realistic surgical operations, the contact force significantly reduced by more than 30% with the force feedback when peeling the egg inner shell membranes.

CONCLUSIONS

Experimental results demonstrate the effectiveness of force feedback and indicate the promise of the presented master-slave robotic system for intraocular surgery assistance.

Miniature Flexible Instrument with Fibre Bragg Grating-Based Triaxial Force Sensing for Intraoperative Gastric Endomicroscopy

Optical biopsy methods, such as probe-based endomicroscopy, can be used to identify early-stage gastric cancer in vivo. However, it is difficult to scan a large area of the gastric mucosa for mosaicking during endoscopy. In this work, we propose a miniaturised flexible instrument based on contact-aided compliant mechanisms and fibre Bragg grating (FBG) sensing for intraoperative gastric endomicroscopy. The instrument has a compact design with an outer diameter of 2.7 mm, incorporating a central channel with a diameter of 1.9 mm for the endomicroscopic probe to pass through. Experimental results show that the instrument can achieve raster trajectory scanning over a large tissue surface with a positioning accuracy of 0.5 mm. The tip force sensor provides a 4.6 mN resolution for the axial force and 2.8 mN for transverse forces. Validation with random samples shows that the force sensor can provide consistent and accurate three-axis force detection. Endomicroscopic imaging experiments were conducted, and the flexible instrument performed no gap scanning (mosaicking area more than 3 mm²) and contact force monitoring during scanning, demonstrating the potential of the system in clinical applications.

Robust Mosaicing of Endomicroscopic Videos via Context-Weighted Correlation Ratio

Probe-based confocal laser endomicroscopy (pCLE) is a promising imaging tool that provides in situ and in vivo optical imaging to perform real-time pathological assessments. However, due to limited field of view, it is difficult for clinicians to get a full understanding of the scanned tissues. In this paper, we develop a novel mosaicing framework to assemble all frame sequences into a full view image. First, a hybrid rigid registration that combines feature matching and template matching is presented to achieve a global alignment of all frames. Then, the parametric free-form deformation (FFD) model with a multiresolution architecture is implemented to accommodate non-rigid tissue distortions. More importantly, we devise a robust similarity metric called context-weighted correlation ratio (CWCR) to promote registration accuracy, where spatial and geometric contexts are incorporated into the estimation of functional intensity dependence. Experiments on both robotic setup and manual manipulation have demonstrated that the proposed scheme significantly precedes some state-of-the-art mosaicing schemes in the presence of intensity fluctuations, insufficient overlap and tissue distortions. Moreover, the comparisons of the proposed CWCR metric and two other metrics have validated the effectiveness of the context-weighted strategy in quantifying the differences between two frames. Benefiting from more rational and delicate mosaics, the proposed scheme is more suitable to instruct diagnosis and treatment during optical biopsies.

Quantitative trait loci (QTL) associated with resistance of rainbow trout Oncorhynchus mykiss against the parasitic ciliate Ichthyophthirius multifiliis

The parasitic ciliate Ichthyophthirius multifiliis has a low host specificity eliciting white spot disease (WSD) in a wide range of freshwater fishes worldwide. The parasite multiplies rapidly whereby the infection may reach problematic levels in a host population within a few days. The parasite targets both wild and cultured fish but the huge economic impact of the protozoan is associated with mortality, morbidity and treatment in aquacultural enterprises. We have investigated the potential for genetic selection of WSD-resistant strains of rainbow trout. Applying the DNA typing system Affymetrix® and characterizing the genome of the individual fish by use of 57,501 single nucleotide polymorphisms (SNP) and their location on the rainbow trout chromosomes, we have genetically characterized rainbow trout with different levels of natural resistance towards WSD. Quantitative trait loci (QTL) used for the selection of breeders with specific markers for resistance are reported. We found a significant association between resistance towards I. multifiliis infection and SNP markers located on the two specific rainbow trout chromosomes Omy 16 and Omy 17. Comparing the expression of immune-related genes in fish-with and without clinical signs-we recorded no significant difference. However, trout surviving the infection showed high expression levels of genes encoding IgT, T-cell receptor TCRβ, C3, cathelicidins 1 and 2 and SAA, suggesting these genes to be associated with protection.

Deep learning-based anatomical site classification for upper gastrointestinal endoscopy

Purpose

Upper gastrointestinal (GI) endoscopic image documentation has provided an efficient, low-cost solution to address quality control for endoscopic reporting. The problem is, however, challenging for computer-assisted techniques, because different sites have similar appearances. Additionally, across different patients, site appearance variation may be large and inconsistent. Therefore, according to the British and modified Japanese guidelines, we propose a set of oesophagogastroduodenoscopy (EGD) images to be routinely captured and evaluate its efficiency for deep learning-based classification methods.

Methods

A novel EGD image dataset standardising upper GI endoscopy to several steps is established following landmarks proposed in guidelines and annotated by an expert clinician. To demonstrate the discrimination of proposed landmarks that enable the generation of an automated endoscopic report, we train several deep learning-based classification models utilising the well-annotated images.

Results

We report results for a clinical dataset composed of 211 patients (comprising a total of 3704 EGD images) acquired during routine upper GI endoscopic examinations. We find close agreement between predicted labels using our method and the ground truth labelled by human experts. We observe the limitation of current static image classification scheme for EGD image classification.

Conclusion

Our study presents a framework for developing automated EGD reports using deep learning. We demonstrate that our method is feasible to address EGD image classification and can lead towards improved performance and additionally qualitatively demonstrate its performance on our dataset.

[Evaluation of inferior mesenteric vessel and ureter by contrast-enhanced abdominal pelvic CT and its clinical influence on laparoscopic rectal surgery]

Objective: To assess the anatomic relationship of inferior mesenteric artery (IMA)/inferior mesenteric vein (IMV) with ureter by contrast-enhanced abdominal pelvic CT, in order to provide guidance for vascular management and ureteral protection in laparoscopic rectal surgery. Methods: A retrospective cohort study was conducted. Image data of contrast-enhanced abdominal pelvic CT at Department of Medical Radiography of Peking University First Hospital in November 2018 were enrolled. Exclusion criteria: (1) previous history of abdominal or pelvic surgery; (2) scoliosis deformities; (3) missing images; (4) minors; (5) inferior mesenteric vascular disease or tumor involvement resulting in suboptimal imaging; (6) poor image quality. Finally, contrast-enhanced abdominal pelvic CT data of 249 cases were collected, including 120 males and 129 females with mean age of (60.1±13.4) years. Multi-planar reconstruction (MPR) and maximum intensity projection (MIP) were used to evaluate the anatomic relationship of IMA/IMV with ureter. IMA root location, IMA length, branch types of IMA, distance between major branches, distance between IMA/IMV and ureter at the level of root of IMA, left colic artery (LCA) root, abdominal aortic bifurcation, and sacral promontory were measured and association between IMA/IMV and ureter site was summarized. Results: The distance from IMA root to the aortic bifurcation and sacral promontory was (42.0±8.5) mm and (101.8±14.0) mm, respectively. The length of IMA was (38.5±10.7) mm. The proportion of IMA roots locating at levels of the 2nd, 3rd, and 4th lumbar vertebra was 3.2% (8/249), 79.5% (198/249), and 17.3% (43/249), respectively. The higher the level of the lumbar vertebra, the longer the IMA [length of IMA originating from the 2nd, 3rd, 4th lumbar vertebra level: (42.4±10.9) mm, (39.5±10.4) mm, (33.0±10.9) mm, respectively; F=7.48, P<0.001]. In 111 cases (44.6%), LCA arose independently from IMA (type 1), and the distance between LCA and the first branch of sigmoid artery (SA) was (15.0±7.4) mm; in 56 cases (22.5%), LCA and SA had a common trunk (type 2), with a length of (11.0±8.5) mm; in 78 cases (31.3%), LCA branched with SA at the same point (type 3); LCA was absent in 4 cases (1.6%)(type 4). The length of IMA in LCA-deficient type 4 was (54.8±18.0) mm, which was longer than (38.2±10.5) mm in LCA-presence type (type 1, type 2 and type 3) and the difference was statistically significant (t=-3.11, P=0.002). The distance between the ureter and IMA was the longest at the level of IMA root [(35.7±8.1) mm], was the shortest at the level of the aortic bifurcation [(22.4±6.4) mm], and the distance between the ureter and IMA in different planes was significantly different (F=185.70, P<0.001). The distance between the ureter and IMV was the longest at the level of the sacral promontory [(21.1±9.0) mm], was the shortest at the level of LCA root [(12.0±5.7) mm], whose difference was also statistically significant (F=87.66, P<0.001). Conclusions: CT post-processing techniques including MPR and MIP can efficiently and accurately assess the branch types of IMA and anatomical relationship between IMA/IMV and ureter, and provide insights into laparoscopic rectal surgery for surgeons. IMA/IMV and ureter depart farthest at the level of IMA root. Artery first and plane second strategy in the middle approach of laparoscopic rectal surgery is considerable and feasible.

Locally Adaptive Total p-Variation Regularization for Non-Rigid Image Registration With Sliding Motion

Due to the complicated thoracic movements which contain both sliding motion occurring at lung surfaces and smooth motion within individual organs, respiratory estimation is still an intrinsically challenging task. In this paper, we propose a novel regularization term called locally adaptive total p-variation (LaTpV) and embed it into a parametric registration framework to accurately recover lung motion. LaTpV originates from a modified L_p-norm constraint (1 < p < 2), where a prior distribution of p modeled by the Dirac-shaped function is constructed to specifically assign different values to voxels. LaTpV adaptively balances the smoothness and discontinuity of the displacement field to encourage an expected sliding interface. Additionally, we also analytically deduce the gradient of the cost function with respect to transformation parameters. To validate the performance of LaTpV, we not only test it on two mono-modal databases including synthetic images and pulmonary computed tomography (CT) images, but also on a more difficult thoracic CT and positron emission tomography (PET) dataset for the first time. For all experiments, both the quantitative and qualitative results indicate that LaTpV significantly surpasses some existing regularizers such as bending energy and parametric total variation. The proposed LaTpV based registration scheme might be more superior for sliding motion correction and more potential for clinical applications such as the diagnosis of pleural mesothelioma and the adjustment of radiotherapy plans.

A bio-inspired self-propelling endoscopic device for inspecting the large intestine

This article presents an inchworm-inspired, pneumatic, endoscopic device intended to navigate inside a colon. The device consists of a propulsion segment with two linear balloons and two gripper segments with four twisted balloons. The three segments can be sequentially actuated by pressurized air, which achieves a propulsive motion like an inchworm. Experimental results of the pneumatic characteristics show that the device has excellent adaptability to pipes of different diameters and good controllability of the propulsion velocity. The device is flexible enough to pass through an elbow pipe without requiring special controls, and the inspection performance of a device equipped with a camera in a flexible pipe is also presented. Moreover, the device is able to advance in an excised swine colon, which shows its great potential for applications in colonoscopy.

Hand-Held Instrument with Integrated Parallel Mechanism for Active Tremor Compensation During Microsurgery

Physiological hand tremor seriously influences the surgical instrument's tip positioning accuracy during microsurgery. To solve this problem, hand-held active tremor compensation instruments are developed to improve tip positioning accuracy during microsurgery. This paper presents the design and performance of a new hand-held instrument that aims to stabilize hand tremors and increase accuracy in microsurgery. The key components are a three degrees of freedom (DOF) integrated parallel manipulator and a high-performance inertial measurement unit (IMU). The IMU was developed to sense the 3-DOF motion of the instrument tip. A customized filter was applied to extract specific hand tremor motion. Then, the instrument was employed to generate the reverse motion simultaneously to reduce tremor motion. Experimental results show that the tremor compensation mechanism is effective. The average RMS reduction ratio of bench test is 56.5% that is a significant tremor reduction ratio. For hand-held test, it has an average RMS reduction ratio of 41.0%. Hence, it could reduce hand tremor magnitudes by 31.7% RMS in 2-DOF.

EEG-Based Spatio-Temporal Convolutional Neural Network for Driver Fatigue Evaluation

Driver fatigue evaluation is of great importance for traffic safety and many intricate factors would exacerbate the difficulty. In this paper, based on the spatial-temporal structure of multichannel electroencephalogram (EEG) signals, we develop a novel EEG-based spatial-temporal convolutional neural network (ESTCNN) to detect driver fatigue. First, we introduce the core block to extract temporal dependencies from EEG signals. Then, we employ dense layers to fuse spatial features and realize classification. The developed network could automatically learn valid features from EEG signals, which outperforms the classical two-step machine learning algorithms. Importantly, we carry out fatigue driving experiments to collect EEG signals from eight subjects being alert and fatigue states. Using 2800 samples under within-subject splitting, we compare the effectiveness of ESTCNN with eight competitive methods. The results indicate that ESTCNN fulfills a better classification accuracy of 97.37% than these compared methods. Furthermore, the spatial-temporal structure of this framework advantages in computational efficiency and reference time, which allows further implementations in the brain-computer interface online systems.

CX3CR1 participates in pulmonary angiogenesis in experimental hepatopulmonary syndrome mice through inhibiting AKT/ERK signaling pathway and regulating NO/NOS release

OBJECTIVE

Hepatopulmonary syndrome (HPS) is a kind of pulmonary microvascular disease and occurs in 15%-30% cirrhosis. This study aimed to investigate the effects of pulmonary CX3CR1 on angiogenesis and associated mechanisms in HPS animal models.

MATERIALS AND METHODS

CX3CR1GFP/GFP mice were constructed by replacing CX3CR1 with GFP. Common bile duct ligation (CBDL) mouse model was established with surgery. Release of nitric oxide (NO) was evaluated. Hematoxylin-eosin (HE) staining was employed to examine the inflammation of lung tissues. CD31 expression was detected with immunohistochemistry assay. Western blotting was used to evaluate the expression of CX3CL1, CX3CR1, phosphorylated-AKT (p-AKT), phosphorylated-ERK (p-ERK). Quantitative Real Time-PCR (qRT-PCR) assay was used to examine VEGF, PDGF, iNOS, eNOS, and HO-1 expression.

RESULTS

CX3CR1-deficiency (CX3CR1GFP/GFP-sham or CX3CR1GFP/GFP-CBDL mice) significantly reduced NO release compared to wide type (WT)-mice or WT-CBDL mice (p<0.05). CX3CR1-deficiency significantly alleviated inflammation compared to wide type (WT)-mice or WT-CBDL mice (p<0.05). CX3CR1-deficiency significantly reduced CD31 expression compared to WT-sham and WT-CBDL mice, respectively (p<0.05). CX3CR1 also participated in anti-angiogenesis efficacy of Bevacizumab. CX3CR1-deficiency significantly down-regulated the ratio of p-AKT/AKT and p-ERK/ERK and inhibited the secretion of VEGF and PDGF compared to WT-mice (p<0.05). CX3CR1-deficiency significantly reduced iNOS, eNOS, and HO-1 expression compared to WT-mice (p<0.05).

CONCLUSIONS

CX3CR1 deficiency reduced VEGF and PDGF production, inhibited p-AKT, and p-ERK activation and down-regulated iNOS, eNOS, and HO-1 expression. Therefore, CX3CR1 participates in pulmonary angiogenesis in the experimental HPS mice via inhibiting AKT/ERK signaling pathway and regulating NO/NOS release. These findings would provide a potential insight for clarifying the pathological mechanisms of HPS.

A hand-held device with 3-DOF haptic feedback mechanism for microsurgery

BACKGROUND

The hand-held devices have the advantages of being compact and easily integrated into surgical workflow especially for microsurgery. However, one of the technical challenges of hand-held device in microsurgery is the lack of force sensing and feedback.

METHODS

This paper presents a hand-held haptic device that converts imperceptible forces into human-perceptible tactile signals. It combines a force sensing tip based on fiber Bragg grating (FBG) sensors that can detect three-degrees-of-freedom (3-DOF) forces, and a haptic feedback mechanism to indicate the magnitude and direction of the forces.

RESULTS

Experimental results demonstrate the ability to measure transverse force at the level of millinewton. User trials have been performed to validate the performance of the haptic feedback. During the phantom experiment, the transverse force was reduced with the feedback mechanism.

CONCLUSIONS

The proposed device provides important insights into the design of hand-held device incorporating real-time force sensing and haptic feedback for microsurgery.

Modular Robotic Scanning Device for Real-Time Gastric Endomicroscopy

Optical biopsy methods, such as probe-based endomicroscopy, can be used for the identification of early mucosal dysplasia in various gastrointestinal conditions and have potential applications in the screening of early-stage gastric cancer in vivo. However, it is difficult to scan a large area of the gastric mucosa for mosaicing during standard endoscopy. This paper proposes a novel 'snap-on' robotic scanning device that can integrate distally with a commercial endoscope. A customized low-cost endomicroscopy system is used for obtaining micro imaging. The developed device could scan a large area of gastric tissue during standard endoscopy. The device achieves positioning accuracy that is less than 0.23 mm. Experimental results showed that the device could achieve large area mosaicing (15.8-18.6 mm²) and demonstrated the potential clinical value of the device for real-time gastric tissue identification and margin assessment. This approach presents an important alternative to current histology techniques for gastrointestinal tract diagnosis.

Water-jet outer sheath with braided shape memory polymer tubes for upper gastrointestinal tract screening

BACKGROUND

Flexible endoscopes have become an important tool for the diagnosis and treatment of gastric cancer. However, there are several limitations to the use of endoscopes in rural areas, including their high cost, poor portability, and unstable platform.

METHODS

This paper presents a novel low-cost outer sheath for stomach screening. The sheath uses braided shape memory polymer (SMP) tubes with a water-jet to control the stiffness and bending motion. The insertion part of the prototype is 250 mm long with a maximum outer diameter of 16 mm and incorporates an internal charge-coupled device camera.

RESULTS

We have tested the workspace and stiffness of the outer sheath. The prototype has also been validated with phantom and ex vivo porcine stomach experiments.

CONCLUSIONS

By controlling the water-jet and temperature of the braided SMP tubes, the outer sheath achieves a large workspace and a remarkable variability in stiffness, demonstrating the potential clinical value of the outer sheath system.

Robotic Scanning Device for Intraoperative Thyroid Gland Endomicroscopy

Probe-based confocal laser endomicroscopy has a high potential to be a promising tool that can provide intraoperative high-resolution in vivo morphological imaging at cellular and subcellular levels for thyroidectomy, and allow real-time assessment of tumor margins. However, the typical images acquired with this technique cover a very small area limited by the field of view of the probe, accompanied by tissue deformation and inconsistent probe-tissue contact when operated manually. In this paper, a novel compact robotic device for large area scanning has been developed. The device can scan a large surface in a spiral trajectory by rotating the tip frame along the spiral groove of the base frame. The fiber Bragg grating sensor with a passive linear structure is used to detect and maintain a stable probe-tissue contact force during scanning. An active linear actuation is also integrated for adjusting the probe-tissue contact level prior to each scan. Results demonstrate that the scanning device ensures a suitable probe-tissue contact force and compensates for simulated hand tremor. Mosaicing results of lens tissue paper and porcine belly tissue with both bench and hand-held experiments show the effectiveness and usability of the device, demonstrating the potential clinical value of the system.

Extrusion of Contracaecum osculatum nematode larvae from the liver of cod (Gadus morhua)

Baltic cod livers have during recent years been found increasingly and heavily infected with third-stage larvae of Contracaecum osculatum. The infections are associated with an increasing population of grey seals which are final hosts for the parasite. Heavy worm burdens challenge utilization and safety of the fish liver products, and technological solutions for removal of worms are highly needed. We investigated the attachment of the worm larvae in liver tissue by use of histochemical techniques and found that the cod host encapsulates the worm larvae in layers of host cells (macrophages, fibroblasts) supported by enclosures of collagen and calcium. A series of incubation techniques, applying compounds targeting molecules in the capsule, were then tested for their effect to induce worm escape/release reactions. Full digestion solutions comprising pepsin, NaCl, HCl and water induced a fast escape of more than 60% of the worm larvae within 20 min and gave full release within 65 min but the liver tissue became highly dispersed. HCl alone, in concentrations of 48 and 72 mM, triggered a corresponding release of worm larvae with minor effect on liver integrity. A lower HCl concentration of 24 mM resulted in 80% release within 35 min. Water and physiological saline had no effect on worm release, and 1% pepsin in water elicited merely a weak escape reaction. In addition to the direct effect of acid on worm behaviour it is hypothesised that the acid effect on calcium carbonate in the encapsulation, with subsequent release of reaction products, may contribute to activation of C. osculatum larvae and induce escape reactions. Short-term pretreatment of infected cod liver and possibly other infected fish products, using low acid concentrations is suggested as part of a technological solution for worm clearance as low acid concentrations had limited macroscopic effect on liver integrity within 35 min.