[Methods and effects of high-frequency color Doppler ultrasound assisted reverse island flap of dorsal digital artery of ulnar thumb for repairing skin and soft tissue defects in the distal end of the same finger]

Objective: To explore the methods and effects of high-frequency color Doppler ultrasound assisted reverse island flap of dorsal digital artery of ulnar thumb for repairing skin and soft tissue defects in the distal end of the same finger. Methods: The retrospective cohort study method was applied. From March 2014 to January 2020, 43 patients with skin and soft tissue defects in the distal end of thumb were hospitalized in the Department of Hand and Foot Surgery of Yidu Central Hospital of Weifang, including 28 males and 15 females, aged 19-58 years. The time from injury to operation was 4 to 10 hours, and the area of wound defect was 1.5 cm×1.0 cm-5.0 cm×3.0 cm. The type and course of dorsal digital artery of ulnar thumb were detected by high-frequency color Doppler ultrasound before operation, based on which the reverse transfer of the island flap of dorsal digital artery of ulnar thumb was designed to repair the skin and soft tissue defects in the distal end of the same finger. The patients with absence of the dorsal digital artery of ulnar thumb were repaired by the greater fish reverse island flap pedicled with the radial palmar artery. The area of the flap was 2.0 cm×1.5 cm-5.5 cm×3.5 cm. The donor site wound was directly closed by suturing or covered with split-thickness skin graft from the inner side of the upper arm in the same arm. The status of dorsal digital artery of ulnar thumb detected by high frequency color Doppler ultrasound before operation was recorded. The type, course, and distribution of the dorsal digital artery of ulnar thumb detected before operation were compared with those observed during the operation. The survival of the flap was observed after operation. During the last follow-up, the appearance of the donor and recipient area of flaps was observed, the thumb function was evaluated with trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association, and the sensory function of the area transplanted with flap was evaluated with the sensory function evaluation standard. Results: The results of high-frequency color Doppler ultrasound showed that the dorsal digital artery of ulnar thumb was absent in 2 patients, while 41 patients had the dorsal digital artery of ulnar thumb, among which 20 cases were type 1 that started from the first dorsal metacarpal artery and ran on the surface of the first interosseous dorsal muscle; 16 cases were type 2 that started from the deep branch of the radial artery or the main artery of thumb and ran in the deep surface of the first interosseous dorsal muscle, including 10 cases of type 2a with the starting point in the basal region of the first metacarpal bone and 6 cases of type 2b with the starting point in the first metacarpal bone region; 5 cases were type 3 that started from the confluence of the first dorsal metacarpal artery and the main thumb artery in the region of the first metacarpophalangeal joint. The outer diameter of the vessel at the beginning of the dorsal digital artery of ulnar thumb was (1.12±0.31) mm, and the outer diameter of the vessel at the beginning of the accompany vein was (0.63±0.21) mm. The dorsal digital artery of ulnar thumb was concentrated in the ulnar side of the first metacarpophalangeal joint and snuff box region. The type, course, and distribution range of the dorsal digital artery of ulnar thumb observed during the operation were consistent with the results detected by high-frequency color Doppler ultrasound before operation. After the operation, the flaps survived in 43 patients. The patients were followed up for 6 months to 1 year. During the last follow-up, only linear scars were left in the donor area; there were no obvious pigmentation in the area transplanted with reverse island flap of dorsal digital artery of ulnar thumb, with good texture and elasticity, and beautiful appearance; the thumb function was evaluated as excellent in 23 cases, good in 17 cases, and fair in 3 cases; the sensory function of the area transplanted with flap was evaluated as S₄ level in 16 cases, S₃ level in 22 cases, and S₂ level in 5 cases. Conclusions: The reverse island flap of dorsal digital artery of ulnar thumb is one of the ideal methods to repair the skin and soft tissue defect in the distal end of the same finger, especially that beyond the distal interphalangeal joint. Preoperative detection with high-frequency color Doppler ultrasound can identify the type and distribution of dorsal digital artery of ulnar thumb, so as to design a personalized operation plan, resulting in good appearance of the donor and recipient area and thumb function after operation.

P–802 The fate and regenerative efficiency of differently administered BMSCs in thin-endometrium rat models

Study question

This study aims to compare the engraftment, retaining time and therapeutic efficiency of differently administered BMSCs and help to select an optimal therapeutic route in clinical settings.

Summary answer

Compared with intrauterine infusion, BMSCs could better promote angiogenesis by upregulating related cytokines, such as VEGF, when administered through the ipsilateral iliac artery.

What is known already

MSC-based therapy has become a promising method for endometrial disease(thin endomtrium or Ashernmen’s syndrowe). Therapeutic effects could always be observed even though different MSC administration routes or MSCs of different tissue sources were used in these studies. Only a few studies compared efficacy of different transplantation routes. However, the results seem to be controversial. Comparable therapeutic effects were reported in some studies, while others stated that systematic administration gave a better outcome than local administration.

Study design, size, duration

Experimental animal study. Forty-eight female Sprague-Dawley (SD) rats were used in this study. They were randomly assigned to 4 groups: normal, injured, intra-arterial and intra-uterine group. For all rats except for normal group, the thin endometrium models were established by infusing 95% ethanol into the uterine horns and BMSCs were transplanted either locally or intra-arterially after modeling. The therapeutic efficacy were evaluated in the following month.

Participants/materials, setting, methods

The thin endometrium models induced by ethanol in SD rats, GFP/Luciferin labeled BMSCs were injected either locally or intra-arterially. The retaining time and quantitative distribution were assessed by in vivo bioluminescence imaging and immune-histological analysis. The precise location and differentiation of differently administered BMSCs were determined by immunofluorescence methods. The endometrial fibrosis, angiogenesis were detected by immunohistochemistry and western blotting at a consecutive time after treatment to compare the therapeutic efficiency of two administration methods.

Main results and the role of chance

The engraftment and differentiation abiility were comparable in 2 groups. The luminescent signal both remained distinct and strong in the abdomen in the first 4 days post-treatment(7.98 × 105 and 6.02 × 105p/s for IU and IA group), indicating the precise and concentrated distribution of BMSCs administered both locally or intra-arterially. The luminescent signals disappeared under bioluminescence imaging over time. We further evaluated the precise distribution, differentiation ability and retaining time of the BMSCs delivered in two strategies by immunofluorescence analysis. All the GFP positive cell localized in stroma, but not in the epithelium or myometrium. Furthermore, there are significantly more positive staining in basal layer of the endometrium close to the glands and vessels than the outer layer of the endometrium in the intra-arterial group. At the 28th days post treatment, we could capture a few GFP staining in the basalis layel of endometrium in intra-arterial group and there were no GFP fluorescence signals detected in intra-uterine group(P < 0.05), suggesting a better survival of BMSCs administered intra-arterially. Differentiation ability of differently administered BMSCs were similar. A few BMSCs began to differentiate into stromal cell 12 days after therapy.

Limitations, reasons for caution

No pregnancy tests were carried out in these rats to further confirm the regeneration of thin endometrium and compare the therapeutic efficacy.

Wider implications of the findings: Our study unveiled that the location of MSCs might determined their regenerarive ability and retaining time, and provided an optimal therapeutic route in clinical settings.

Trial registration number

Not applicable

[Exploration of the theoretical system of membrane anatomy in colorectal surgery]

Despite the concept of membrane anatomy has been widely used in minimally invasive colorectal surgery, the definition of membrane anatomy and the establishment of membrane plane remain controversial. Therefore, it is difficult to establish a unified theoretical system of membrane anatomy. Through embryological studies and anatomical findings on the integrity and continuity of membranes, we try to discuss the theoretical system of membrane anatomy in colorectal surgery from three aspects: membrane anatomical system, membrane anatomical elements and membrane anatomical mechanism. The establishment of a unified theoretical system of membrane anatomy will not only contribute to the standardization operative procedures, but also to the establishment of uniform surgical standards for colorectal cancer.

[Utility of the type 3 portable monitor for the diagnosis of sleep disordered breathing in patients with stable heart failure]

Objective: To evaluate the utility of a type 3 portable monitor (PM) at home for the diagnosis of sleep disordered breathing (SDB) in patients with stable congestive heart failure (CHF). Methods: Seventy-six consecutive patients with CHF (61 males, 15 females, mean±standard deviation age (57.0±16.9) years) were enrolled from the sleep center of Peking university People's Hospital during January 2016 to January 2019, and underwent overnight, unattended home sleep apnea testing (HSAT) with a portable monitor followed by an overnight simultaneous polysomnogram (PSG) with in-laboratory portable monitor (in-lab PM) recording within one week. The consistency of apnea hypopnea index (AHI), obstructive sleep apnea index (OAI), central sleep apnea index (CAI) between HSAT and PSG as well as the in-lab PM and PSG were analyzed by Bland-Altman plot; the sensitivity and specificity of PM for the diagnosis of SDB in patients with CHF were evaluated. Results: The number of patients included in the final analysis were 65 in HSAT, 63 in in-lab PM and 65 in PSG. AHI [M(Q₁,Q₃)] was 26.1 (10.9,40.1) events/h by HSAT, 27.9 (11.3,43.2) events/h by in-lab PM, both were not different from AHI 29.0 (10.2,45.0) events/h by PSG (P>0.05). The AHI, OAI and CAI assessed by HSAT correlated significantly with those by PSG (r=0.892, 0.903, 0.831, P<0.05). Bland-Altman analysis of AHI, OAI, CAI by PSG versus HSAT showed a mean difference of 3.1 events/h, 0.8 events/h, 1.2 events/h; limits of consistency were -15.2 to 21.4 events/h, -9.7 to 11.3 events/h, -10.9 to 13.2 events/h, respectively. Based on a threshold of AHI ≥5 events/h, HSAT had 94.6% sensitivity, 75% specificity, compared to PSG. For detecting Cheyne-Stokes respiration (CSR), a sensitivity of 96.4%,a specificity of 97.2% were achieved, compared to PSG. Conclusion: Type 3 PM can be used to diagnose SDB in patients with CHF.

AB0682 RHEUMATOLOGY TEACHING IN TIMES OF COVID-19

Background:

The COVID-19 pandemic has affected the delivery of face-to-face teaching especially bedside teaching for medical students in the hospitals. Rheumatology outpatient clinics have mostly become virtual or telephone consultation clinics which prevent medical students from seeing patients in person. Students are deprived of the opportunities to take rheumatology history, examining patients and seeing signs of rheumatologic diseases. New adaptations have to be made to ensure equitability and that students still receive the relevant teaching in line with their learning curriculum and to help them prepare for their examinations.

Objectives:

Our aims are:

1)To adapt bedside teaching in the wards to simulated teaching in the classroom using trained simulated ‘patients’; and

2)To create simulation teaching of patient journeys in Objective Structured Clinical Examination (OSCE) format known as Clinically Observed Medical Education Tutorials (COMET) (Nair et al., 2001).

Methods:

1)For simulated teaching in the classroom, we have trained our teaching colleagues as simulated or standardized patients (SPs). We write up fictitious patient histories which simulate common presentations at rheumatology clinics. We train the SPs to give as accurate a history as possible and to simulate pains in different joints (e.g. pain at the metacarpophalangeal joints and proximal interphalangeal joints in rheumatoid arthritis) on clinical examinations. For clinical presentations that are not easily simulated, we use photographs of the relevant signs. This method is used not only as formative assessments but also as end-of-placement summative assessments.

2)COMET comprises 3 OSCE-style stations with a tutor each where the students perform different tasks based on a patient’s clinical problem (e.g. acute hot swollen joint). The first station is initial A-to-E assessment of the patient (using a simulator), followed by investigations and interpretations of lab results and imaging (station 2) and lastly, management (including prescribing medications) and communication skills (e.g. explain arthrocentesis to the patient).

Results:

The overall feedback from students is very positive. We use Likert scale to assess confidence level before and after the teaching session, and pre-session and post-session multiple choice questions to assess learning and knowledge gained.

Conclusion:

While simulated teaching cannot replace encounters with real patients, students do enjoy these sessions as they get to ‘experience’ a large variety of rheumatologic cases and practice their clinical skills which at times are limited with real patients due to reluctance and pain of the patients.

References:

[1]Nair, R., Morrissey, J., Carasco, D., Desilva, S. & Patel, V. (2001) COMET: Clinically Observed Medical Education Tutorial - a novel educational method in clinical skills. International Journal of Clinical Skills

[2]Van der Vleuten, C.P.M. & Swanson, D.B. (1990) Assessment of clinical skills with standardized patients: state of the art. Teach Learn Med, 2: 58-76.

Disclosure of Interests:

None declared

Gut Microbiota May Mediate the Influence of Periodontitis on Prediabetes

Mounting evidence has shown that periodontitis is associated with diabetes. However, a causal relationship remains to be determined. Recent studies reported that periodontitis may be associated with gut microbiota, which plays an important role in the development of diabetes. Therefore, we hypothesized that gut microbiota might mediate the link between periodontitis and diabetes. Periodontitis was induced by ligatures. Glycemic homeostasis was evaluated through fasting blood glucose (FBG), serum glycosylated hemoglobin (HbA1c), and intraperitoneal glucose tolerance test. Micro-computed tomography and hematoxylin and eosin staining were used to evaluate periodontal destruction. The gut microbiota was analyzed using 16S ribosomal RNA gene sequencing and bioinformatics. Serum endotoxin, interleukin (IL) 6, tumor necrosis factor α (TNF-α), and IL-1β were measured to evaluate the systemic inflammation burden. We found that the levels of FBG, HbA1c, and glucose intolerance were higher in the periodontitis (PD) group than in the control (Con) group (P < 0.05). When periodontitis was eliminated, the FBG significantly decreased (P < 0.05). Several butyrate-producing bacteria were decreased in the gut microbiota of the PD group, including Lachnospiraceae_NK4A136_group, Eubacterium_fissicatena_group, Eubacterium_coprostanoligenes_group, and Ruminococcaceae_UCG-014 (P < 0.05), which were negatively correlated with serum HbA1c (P < 0.05). Subsequently, the gut microbiota was depleted using antibiotics or transplanted through cohousing. Compared with the PD group, the levels of HbA1c and glucose intolerance were decreased in the gut microbiota-depleted mice with periodontitis (PD + Abx) (P < 0.05), as well as the serum levels of endotoxin and IL-6 (P < 0.05). The serum levels of IL-6, TNF-α, and IL-1β in the PD + Abx group were higher than those of the Con group (P < 0.05). Antibiotics exerted a limited impact on the periodontal microbiota. When the PD mice were cohoused with healthy ones, the elevated FBG and HbA1c significantly recovered (P < 0.05), as well as the aforementioned butyrate producers (P < 0.05). Thus, within the limitations of this study, our data indicated that the gut microbiota may mediate the influence of periodontitis on prediabetes.

33 Diagnostic Test Accuracy of the 4AT for Delirium Detection: Systematic Review and Meta-Analysis

Introduction

Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 ‘A’s Test (4AT; www.the4AT.com) is a short (&lt;2 min) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection.

Methods

We searched the following electronic databases through Ovid: MEDLINE, Embase, and PsycINFO. Additional databases were searched: CINAHL (EBSCOhost), clinicaltrials.gov and Cochrane Central Register of Controlled Trials from 2011 (4AT publication) until 21 December 2019. Inclusion criteria: older adults (≥65) across any setting of care except critical care; validation study of the 4AT against a delirium reference standard (standard diagnostic criteria or validated tool). Two reviewers independently screened abstracts and papers and performed the data extraction. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model.

Results

17 studies (n = 3,701 observations) were included. Various settings including acute medicine, surgery, stroke wards and the emergency department were represented. The overall prevalence of delirium was 24.2% (95% CI 17.8–32.1%; range 10.5–61.9%). The pooled sensitivity was 0.88 (95% CI 0.80–0.93) and the pooled specificity was 0.88 (95% CI 0.82–0.92). The methodological quality of studies was mostly good.

Conclusions

The 4AT is now supported by a substantial evidence base comparable to other well-studied tools such as the Confusion Assessment Method (CAM). The strong pooled sensitivity and specificity findings for the 4AT in this meta-analysis along with its brevity and lack of need for specific training provide support for its use as an effective assessment tool for delirium.

One-step purification and immobilization of recombinant proteins using SpyTag/SpyCatcher chemistry

Based on the specific and spontaneous formation of isopeptide bonds by SpyCatcher/SpyTag, we have developed a one-step method for purification and immobilization of recombinant proteins. The procedure is to immobilize SpyCatcher on glyoxyl agarose gels, and then the SpyCatcher immobilisate can be used to immobilize the SpyTag-fused protein in the crude extract selectively. A mutant of SpyCatcher (mSC), in which a peptide (LysGlyLysGlyLysGly) was added to the C-terminus of SpyCatcher and three lysine residues around the SpyTag/SpyCatcher binding domain were replaced with arginine, was designed to improve the attachment of SpyCatcher to the support. Compared with wild-type SpyCatcher, mSC can be immobilized on the glyoxyl-agarose support more efficiently, which enables the obtained mSC derivative a high binding capacity of the SpyTag-fused protein. The results showed that the target proteins in the crude enzyme extract were purified and immobilized in one step, and the thermal stability of the immobilized target proteins was also remarkably improved.

Extracorporeal membrane oxygenation (ECMO) in patients with COVID-19: a rapid systematic review of case studies

OBJECTIVE

COVID-19 can cause severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) can support gas exchange in patients failing conventional mechanical ventilation, but its role is still controversial. We performed a rapid systematic review focusing on the use of ECMO in patients with COVID-19.

MATERIALS AND METHODS

PubMed/MEDLINE, Google Scholar, Embase, the Cochrane Library, EBSCO and Ovid (updated 30 April 2020) were systematically searched. Case reports/Case series from COVID-19 patients treated with ECMO were included in the study. Three reviewers assessed, selected, and abstracted data from studies. All disparate opinions were resolved through discussion.

RESULTS

We included 13 articles for systematic evaluation, including 10 case reports and 3 case series studies, with a total of 72 patients. We search for the following information: First author of articles; Patient's location; age; gender; body mass index (BMI); Comorbidities; Time on ECMO; Mode of ECMO; treatments and clinical outcomes. As of all reporting times, our data show that 38 patients (52.8%) have died definitively, 13 patients (18.0%) were still receiving ECMO treatment, 12 patients (16.7%) were alive, 7 patients (9.7%) were recovery and 2 cases (2.8%) remained hospitalized.

CONCLUSIONS

ECMO plays an important role in the stabilization and survival critically ill patients with COVID-19, but the usefulness of ECMO in reducing the mortality of severe ARDS caused by COVID-19 was limited. Therefore, a larger sample size study and a comprehensive analysis of evaluating the medical value of using ECMO on COVID-19 patients are urgently required.

Leukocyte immunoglobulin-like receptor A3 is increased in IBD patients and functions as an anti-inflammatory modulator

Growing evidence shows that a homozygous 6·7-kb deletion of the novel anti-inflammatory molecule leukocyte immunoglobulin-like receptor A3 (LILRA3) is associated with many autoimmune disorders. However, its effects on pathogenesis of inflammatory bowel disease (IBD) have yet not been clarified. LILRA3 is mainly expressed in monocytes, whereas its effects on biological behaviors of monocytes have not been systematically reported. In our study, to investigate the association between LILRA3 polymorphism and IBD susceptibility, LILRA3 polymorphism was assessed in 378 IBD patients and 509 healthy controls. Quantitative real time PCR (qRT-PCR), Western blot and immunohistochemistry (IHC) were employed to detect the LILRA3 expression in IBD patient blood and intestinal samples. The human U937 monocyte cell line was employed to establish LILRA3 over-expressing cells and the effects of LILRA3 on the biological behaviors of U937 cells were systematically explored. Although no association of the polymorphism with IBD development was found, LILRA3 expression was markedly increased in IBD patients compared with healthy controls. Over-expression of LILRA3 in monocytes led to significant decreases in secretion of interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-6. Additionally, LILRA3 abated monocyte migration by reducing the expression of several chemokines and enhanced monocyte phagocytosis by increasing CD36 expression. Furthermore, LILRA3 promoted monocyte proliferation through a combination of Akt and extracellular receptor kinase/mitogen-activated protein kinase (Erk/MEK) signaling pathways. We report for the first time, to our knowledge, that LILRA3 is related to IBD and functions as an anti-inflammatory modulator in U937 cells.

Bio-detoxification of Jatropha curcas L. cake by a soil-borne Mucor circinelloides strain using a zebrafish survival model and solid-state fermentation

AIMS

The aims of the study were to (i) improve the evaluation criteria of detoxifying Jatropha curcas L. cake (JCC), (ii) isolate and characterize a JCC tolerant strain, (iii) explore its JCC detoxifying potential.

METHODS AND RESULTS

The zebrafish was employed as a survival model to screen the strains capable of detoxifying JCC. A strain identified as Mucor circinelloides SCYA25, which is highly capable of degrading all toxic components, was isolated from soil. Different solid-state fermentation parameters were optimized by response surface methodology. The optimal values for inoculation amount, moisture content, temperature, and time were found to be 18% (1·8 × 10⁶ spores g^-1 cake), 66%, 26, and 36 days, respectively, to achieve maximum detoxification of the JCC (92%). Under optimal fermentation conditions, the protein content of JCC was increased, while the concentrations of ether extract, crude fiber, toxins, and anti-nutritional substances were all degraded considerably (P < 0·05). Scanning electron microscopy and Fourier transform infrared spectrometer analysis revealed that the fermentation process could disrupt the surface structure and improve the ratio of α-helix to β-folding in the JCC protein, which may improve the digestibility when the detoxified JCC is used as a feedstuff.

CONCLUSIONS

Our results indicate that M. circinelloides SCYA25 is able to detoxify JCC and improve its nutritional profile, which is beneficial to the safe utilization of JCC as a protein feedstuff.

SIGNIFICANCE AND IMPACT OF THE STUDY

The newly identified M. circinelloides SCYA25 detoxified JCC in a safe manner to provide a potential alternative to soybean meal for the feed industry. These results also provide a new perspective and method for the toxicity evaluation and utilization of JCC and similar toxic agricultural by-products.