[Clinical features and follow-up study on 55 patients with adolescence-onset methylmalonic acidemia]

Objective: To investigate the clinical features and outcomes of adolescence-onset methylmalonic acidemia (MMA) and explore preventive strategies. Methods: This was a retrospective case analysis of the phenotypes, genotypes and prognoses of adolescence-onset MMA patients. There were 55 patients diagnosed in Peking University First Hospital from January 2002 to June 2023, the data of symptoms, signs, laboratory results, gene variations, and outcomes was collected. The follow-ups were done through WeChat, telephone, or clinic visits every 3 to 6 months. Results: Among the 55 patients, 31 were males and 24 were females. The median age of onset was 12 years old (range 10-18 yearsold). They visited clinics at Tanner stages 2 to 5 with typical secondary sexual characteristics. Nine cases (16%) were trigged by infection and 5 cases (9%) were triggered by insidious exercises. The period from onset to diagnosis was between 2 months and 6 years. Forty-five cases (82%) had neuropsychiatric symptoms as the main symptoms, followed by cardiovascular symptoms in 12 cases (22%), kidney damage in 7 cases (13%), and eye disease in 12 cases (22%). Fifty-four cases (98%) had the biochemical characteristics of methylmalonic acidemia combined with homocysteinemia, and 1 case (2%) had the isolated methylmalonic acidemia. Genetic diagnosis was obtained in 54 cases, with 20 variants identified in MMACHC gene and 2 in MMUT gene. In 53 children with MMACHC gene mutation,1 case had dual gene variants of PRDX1 and MMACHC, with 105 alleles. The top 5 frequent variants in MMACHC were c.482G>A in 39 alleles (37%), c.609G>A in 17 alleles (16%), c.658_660delAAG in 11 alleles (10%), c.80A>G in 10 alleles (10%), c.567dupT and c.394C>T both are 4 alleles (4%). All patients recovered using cobalamin, L-carnitine, betaine, and symptomatic therapy, and 54 patients (98%) returned to school or work. Conclusions: Patients with adolescence-onset MMA may triggered by fatigue or infection. The diagnosis is often delayed due to non-specific symptoms. Metabolic and genetic tests are crucial for a definite diagnosis. Treatment with cobalamin, L-carnitine, and betaine can effectively reverse the prognosis of MMA in adolescence-onset patients.

Indirect Correlative Light and Electron Microscopy (iCLEM): A Novel Pipeline for Multiscale Quantification of Structure From Molecules to Organs

Correlative light and electron microscopy (CLEM) methods are powerful methods that combine molecular organization (from light microscopy) with ultrastructure (from electron microscopy). However, CLEM methods pose high cost/difficulty barriers to entry and have very low experimental throughput. Therefore, we have developed an indirect correlative light and electron microscopy (iCLEM) pipeline to sidestep the rate-limiting steps of CLEM (i.e., preparing and imaging the same samples on multiple microscopes) and correlate multiscale structural data gleaned from separate samples imaged using different modalities by exploiting biological structures identifiable by both light and electron microscopy as intrinsic fiducials. We demonstrate here an application of iCLEM, where we utilized gap junctions and mechanical junctions between muscle cells in the heart as intrinsic fiducials to correlate ultrastructural measurements from transmission electron microscopy (TEM), and focused ion beam scanning electron microscopy (FIB-SEM) with molecular organization from confocal microscopy and single molecule localization microscopy (SMLM). We further demonstrate how iCLEM can be integrated with computational modeling to discover structure-function relationships. Thus, we present iCLEM as a novel approach that complements existing CLEM methods and provides a generalizable framework that can be applied to any set of imaging modalities, provided suitable intrinsic fiducials can be identified.

[Clinical and electrophysiological characteristics and treatment outcomes of anti-neutrophil cytoplasmic antibody ANCA-associated vasculitic neuropathy]

Objective: To investigate the clinical and electrophysiological characteristics of ANCA-associated vasculitic neuropathy (VN) and analyze the predictors of treatment outcomes. Methods: Retrospective case series. In all, 652 consecutive patients with ANCA-associated vasculitis were admitted to the First Medical Center of the Chinese PLA General Hospital between January 2006 and December 2022. Peripheral neuropathy occurred in 91 patients. Patients were excluded if other known causes of neuropathy were present. Sixty-one patients were eventually enrolled, including 17 with eosinophilic granulomatosis with polyangiitis (EGPA), 11 with granulomatosis polyangiitis (GPA), and 33 with microscopic polyangiitis (MPA). Their clinical data were collected and clinical characteristics, VN manifestations, electrophysiological findings (including interside amplitude ratio [IAR]), and treatment outcomes were compared among the three subsets of AAV. Then, factors influencing the treatment outcomes were analyzed using multivariable logistic regression analysis. Results: Peripheral neuropathy occurred in 62.1%(18/29) of EGPA, 8.3%(15/180) of GPA, and 13.1%(58/443) of MPA patients. The age at onset and examination was higher in patients with MPA than those with EGPA or GPA (P<0.01). The occurrence of VN was later in patients with GPA than those with EGPA (P<0.01), and the GPA group had fewer affected nerves than the other two groups (P<0.016). The abnormal IARs of motor nerves in lower limbs were more detected in the EGPA than the MPA group (P<0.01). Logistic regression analysis suggested that higher Birmingham vasculitis activity score-version 3 (BVAS-V3) (OR=6.85, 95%CI 1.33-35.30) was associated with better treatment outcomes of VN. However, central nervous system involvement was a risk factor for poor treatment outcomes (OR=0.13, 95%CI 0.02-0.89). Conclusions: The clinical and electrophysiological characteristics of VN were slightly different among subsets of AAV. Patients with GPA often presented with polyneuropathy and had fewer nerves affected; mononeuritis multiplex was more common in EGPA than GPA and MPA. Higher BVAS-V3 and central nervous system involvement might predict the treatment outcome of VN.

Histone 3 lysine 9 acetylation-specific reprogramming regulates esophageal squamous cell carcinoma progression and metastasis

Dysregulation of histone acetylation is widely implicated in tumorigenesis, yet its specific roles in the progression and metastasis of esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we profiled the genome-wide landscapes of H3K9ac for paired adjacent normal (Nor), primary ESCC (EC) and metastatic lymph node (LNC) esophageal tissues from three ESCC patients. Compared to H3K27ac, we identified a distinct epigenetic reprogramming specific to H3K9ac in EC and LNC samples relative to Nor samples. This H3K9ac-related reprogramming contributed to the transcriptomic aberration of targeting genes, which were functionally associated with tumorigenesis and metastasis. Notably, genes with gained H3K9ac signals in both primary and metastatic lymph node samples (common-gained gene) were significantly enriched in oncogenes. Single-cell RNA-seq analysis further revealed that the corresponding top 15 common-gained genes preferred to be enriched in mesenchymal cells with high metastatic potential. Additionally, in vitro experiment demonstrated that the removal of H3K9ac from the common-gained gene MSI1 significantly downregulated its transcription, resulting in deficiencies in ESCC cell proliferation and migration. Together, our findings revealed the distinct characteristics of H3K9ac in esophageal squamous cell carcinogenesis and metastasis, and highlighted the potential therapeutic avenue for intervening ESCC through epigenetic modulation via H3K9ac.

[Analysis of 9 patients with adolescence-onset methylenetetrahydrofolate reductase deficiency]

Objective: To explore the diagnosis and treatment of adolescence-onset methylenetetrahydrofolate reductase (MTHFR) deficiency. Methods: This was a retrospective case study. Nine patients with adolescence-onset MTHFR deficiency were diagnosed at Peking University First Hospital from January 2016 to December 2022, and followed up for more than 1 year. Their general information, clinical manifestations, laboratory tests, cranial images, MTHFR gene variants, diagnosis, treatment, and outcome were analyzed retrospectively. Results: The 9 patients came from 8 families. They had symptoms at age of 8.0 years to 17.0 years and diagnosed at 9.0 years to 17.5 years. Eight were male and 1 was female. Two patients were brothers, the elder brother developed abnormal gait at 17.0 years; and the younger brother was then diagnosed at 15.0 years of age and treated at the asymptomatic stage, who was 18.0 years old with normal condition during this study. The main manifestations of the 8 symptomatic patients included progressive dyskinesia and spastic paralysis of the lower limbs, with or without intellectual decline, cognitive impairment and behavioral abnormalities. Totally, 15 variants of MTHFR gene were identified in the 9 patients, including 8 novel variants. Five patients had brain image abnormalities. Increased plasma total homocysteine level (65-221 μmol/L) was found in all patients, and decreased to 20-70 μmol/L after treatment with betaine and calcium folinate. Besides, the 8 symptomatic patients had their behavior and cognitive problems significantly improved, with a legacy of lower limb motor disorders. Conclusions: Late-onset MTHFR deficiency can occur in adolescence. The diagnosis is usually delayed because of non-specific clinical symptoms. The test of blood total homocysteine could be used as a selective screening test. Eight novel varients of MTHFR gene were identified. Timely treatment can improve clinical condition significantly, and pre-symptomatic treatment may prevent brain damage.

[Multicenter retrospect analysis of early clinical features and analysis of risk factors on prognosis of elderly patients with severe burns]

Objective: To investigate the early clinical characteristics of elderly patients with severe burns and the risk factors on prognosis. Methods: This study was a retrospective case series study. Clinical data of 124 elderly patients with severe burns who met the inclusion criteria and were admitted to the 12 hospitals from January 2015 to December 2020 were collected, including 4 patients from the Fourth People's Hospital of Dalian, 5 patients from Fujian Medical University Union Hospital, 22 patients from Guangzhou Red Cross Hospital of Jinan University, 5 patients from Heilongjiang Provincial Hospital, 27 patients from the First Affiliated Hospital of Naval Medical University, 9 patients from the First Affiliated Hospital of Nanchang University, 10 patients from Affiliated Hospital of Nantong University, 9 patients from Tongren Hospital of Wuhan University & Wuhan Third Hospital, 12 patients from the 924th Hospital of PLA, 6 patients from Zhangjiagang First People's Hospital, 4 patients from Taizhou Hospital of Zhejiang Province, and 11 patients from Zhengzhou First People's Hospital. The patients' overall clinical characteristics, such as gender, age, body mass index, total burn area, full-thickness burn area, inhalation injury, causative factors, whether combined with underlying medical diseases, and admission time after injury were recorded. According to the survival outcome within 28 days after injury, the patients were divided into survival group (89 cases) and death group (35 cases). The following data of patients were compared between the two groups, including the basic data and injuries (the same as the overall clinical characteristics ahead); the coagulation indexes within the first 24 hours of injury such as prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, D-dimer, fibrinogen degradation product (FDP), international normalized ratio (INR), and fibrinogen; the blood routine indexes within the first 24 hours of injury such as white blood cell count, platelet count, neutrophil-to-lymphocyte ratio, monocyte count, red blood cell count, hemoglobin, and hematocrit; the organ function indexes within the first 24 hours of injury such as direct bilirubin, total bilirubin, urea, serum creatinine, aspartate aminotransferase, alanine aminotransferase, total protein, albumin, globulin, blood glucose, triglyceride, total cholesterol, alkaline phosphatase, creatine kinase, electrolyte indexes (potassium, sodium, chlorine, calcium, magnesium, and phosphorus in blood), uric acid, myoglobin, and brain natriuretic peptide; the infection and blood gas indexes within the first 24 hours of injury such as procalcitonin, C-reactive protein, pH value, oxygenation index, base excess, and lactate; treatment such as whether conducted with mechanical ventilation, whether conducted with continuous renal replacement therapy, whether conducted with anticoagulation therapy, whether applied with vasoactive drugs, and fluid resuscitation. The analysis was conducted to screen the independent risk factors for the mortality within 28 days after injury in elderly patients with severe burns. Results: Among 124 patients, there were 82 males and 42 females, aged 60-97 years, with body mass index of 23.44 (21.09, 25.95) kg/m2, total burn area of 54.00% (42.00%, 75.00%) total body surface area (TBSA), and full-thickness burn area of 25.00% (10.00%, 40.00%) TBSA. The patients were mainly combined with moderate to severe inhalation injury and caused by flame burns. There were 43 cases with underlying medical diseases. The majority of patients were admitted to the hospital within 8 hours after injury. There were statistically significant differences between patients in the 2 groups in terms of age, total burn area, full-thickness burn area, and inhalation injury, and PT, APTT, D-dimer, FDP, INR, white blood cell count, platelet count, urea, serum creatinine, blood glucose, blood sodium, uric acid, myoglobin, and urine volume within the first 24 hours of injury (with Z values of 2.37, 5.49, 5.26, 5.97, 2.18, 1.95, 2.68, 2.68, 2.51, 2.82, 2.14, 3.40, 5.31, 3.41, 2.35, 3.81, 2.16, and -3.82, respectively, P<0.05); there were statistically significant differences between two groups of patients in whether conducted with mechanical ventilation and whether applied with vasoactive drugs (with χ2 values of 9.44 and 28.50, respectively, P<0.05). Age, total burn area, full-thickness burn area, serum creatinine within the first 24 hours of injury, and APTT within the first 24 hours of injury were the independent risk factors for the mortality within 28 days after injury in elderly patients with severe burns (with odds ratios of 1.17, 1.10, 1.10, 1.09, and 1.27, 95% confidence intervals of 1.03-1.40, 1.04-1.21, 1.05-1.19, 1.05-1.17, and 1.07-1.69, respectively, P<0.05). Conclusions: The elderly patients with severe burns had the injuries mainly from flame burns, often accompanied by moderate to severe inhalation injury and enhanced inflammatory response, elevated blood glucose levels, activated fibrinolysis, and impaired organ function in the early stage, which are associated with their prognosis. Age, total burn area, full-thickness burn area, and serum creatinine and APTT within the first 24 hours of injury are the independent risk factors for death within 28 days after injury in this population.

Gut microbiota dynamics and fecal SCFAs after colonoscopy: accelerating microbiome stabilization by Clostridium butyricum

BACKGROUND

Colonoscopy is a classic diagnostic method with possible complications including abdominal pain and diarrhoea. In this study, gut microbiota dynamics and related metabolic products during and after colonoscopy were explored to accelerate gut microbiome balance through probiotics.

METHODS

The gut microbiota and fecal short-chain fatty acids (SCFAs) were analyzed in four healthy subjects before and after colonoscopy, along with seven individuals supplemented with Clostridium butyricum. We employed 16S rRNA sequencing and GC-MS to investigate these changes. We also conducted bioinformatic analysis to explore the buk gene, encoding butyrate kinase, across C. butyricum strains from the human gut.

RESULTS

The gut microbiota and fecal short-chain fatty acids (SCFAs) of four healthy subjects were recovered on the 7th day after colonoscopy. We found that Clostridium and other bacteria might have efficient butyric acid production through bioinformatic analysis of the buk and assessment of the transcriptional level of the buk. Supplementation of seven healthy subjects with Clostridium butyricum after colonoscopy resulted in a quicker recovery and stabilization of gut microbiota and fecal SCFAs on the third day.

CONCLUSION

We suggest that supplementation of Clostridium butyricum after colonoscopy should be considered in future routine clinical practice.

DeepGraFT: A novel semantic segmentation auxiliary ROI-based deep learning framework for effective fundus tessellation classification

Fundus tessellation (FT) is a prevalent clinical feature associated with myopia and has implications in the development of myopic maculopathy, which causes irreversible visual impairment. Accurate classification of FT in color fundus photo can help predict the disease progression and prognosis. However, the lack of precise detection and classification tools has created an unmet medical need, underscoring the importance of exploring the clinical utility of FT. Thus, to address this gap, we introduce an automatic FT grading system (called DeepGraFT) using classification-and-segmentation co-decision models by deep learning. ConvNeXt, utilizing transfer learning from pretrained ImageNet weights, was employed for the classification algorithm, aligning with a region of interest based on the ETDRS grading system to boost performance. A segmentation model was developed to detect FT exits, complementing the classification for improved grading accuracy. The training set of DeepGraFT was from our in-house cohort (MAGIC), and the validation sets consisted of the rest part of in-house cohort and an independent public cohort (UK Biobank). DeepGraFT demonstrated a high performance in the training stage and achieved an impressive accuracy in validation phase (in-house cohort: 86.85 %; public cohort: 81.50 %). Furthermore, our findings demonstrated that DeepGraFT surpasses machine learning-based classification models in FT classification, achieving a 5.57 % increase in accuracy. Ablation analysis revealed that the introduced modules significantly enhanced classification effectiveness and elevated accuracy from 79.85 % to 86.85 %. Further analysis using the results provided by DeepGraFT unveiled a significant negative association between FT and spherical equivalent (SE) in the UK Biobank cohort. In conclusion, DeepGraFT accentuates potential benefits of the deep learning model in automating the grading of FT and allows for potential utility as a clinical-decision support tool for predicting progression of pathological myopia.

Activation of Ca2+ transport in cardiac microsomes enriches functional sets of ER and SR proteins

The importance of sarcoplasmic reticulum (SR) Ca2+-handling in heart has led to detailed understanding of Ca2+-release and re-uptake protein complexes, while less is known about other endoplasmic reticulum (ER) functions in the heart. To more fully understand cardiac SR and ER functions, we analyzed cardiac microsomes based on their increased density through the actions of the SR Ca2+-ATPase (SERCA) and the ryanodine receptor that are highly active in cardiomyocytes. Crude cardiac microsomal vesicles loaded with Ca oxalate produced two higher density subfractions, MedSR and HighSR. Proteins from 20.0 μg of MV, MedSR, and HighSR protein were fractionated using SDS-PAGE, then trypsinized from 20 separate gel pieces, and analyzed by LC-MS/MS to determine protein content. From 62,000 individual peptide spectra obtained, we identified 1105 different proteins, of which 354 were enriched ≥ 2.0-fold in SR fractions compared to the crude membrane preparation. Previously studied SR proteins were all enriched, as were proteins associated with canonical ER functions. Contractile, mitochondrial, and sarcolemmal proteins were not enriched. Comparing the levels of SERCA-positive SR proteins in MedSR versus HighSR vesicles produced a range of SR subfraction enrichments signifying differing levels of Ca2+ leak co-localized in the same membrane patch. All known junctional SR proteins were more enriched in MedSR, while canonical ER proteins were more enriched in HighSR membrane. Proteins constituting other putative ER/SR subdomains also exhibited average Esub enrichment values (mean ± S.D.) that spanned the range of possible Esub values, suggesting that functional sets of proteins are localized to the same areas of the ER/SR membrane. We conclude that active Ca2+ loading of cardiac microsomes, reflecting the combined activities of Ca2+ uptake by SERCA, and Ca2+ leak by RyR, permits evaluation of multiple functional ER/SR subdomains. Sets of proteins from these subdomains exhibited similar enrichment patterns across membrane subfractions, reflecting the relative levels of SERCA and RyR present within individual patches of cardiac ER and SR.

Weizmannia coagulans BCF-01: a novel gastrogenic probiotic for Helicobacter pylori infection control

The widespread prevalence of Helicobacter pylori infection, particularly in China, contributes to the development of gastrointestinal diseases. Antibiotics have limitations, including adverse reactions and increased antibiotic resistance. Therefore, identification of novel gastrogenic probiotics capable of surviving the acidic gastric environment and effectively combating H. pylori infection has potential in restoring gastric microbiota homeostasis. Five novel strains of human gastrogenic Weizmannia coagulans (BCF-01-05) were isolated from healthy gastric mucosa and characterized using 16S rDNA identification. Acid resistance, H. pylori inhibition, and adherence to gastric epithelial cells were evaluated in in-vitro experiments and the molecular mechanism explored in in-vivo experiments. Among the gastric-derived W. coagulans strains, BCF-01 exhibited the strongest adhesion and H. pylori inhibition, warranting further in-vivo safety evaluation. Through 16S rRNA sequencing of a mouse model, BCF-01 was determined to significantly restore H. pylori-associated gastric dysbiosis and increase the abundance of potential probiotic bacteria. Furthermore, BCF-01 enhanced mucosal tight junction protein expression and inhibited the TLR4-NFκB-pyroptosis signaling pathway in macrophages, as demonstrated by qRT-PCR and western blotting.These findings highlight the potential of BCF-01 in the prevention and control of H. pylori infection. Specifically, treatment with BCF-01 effectively restored gastric microecology and improved H. pylori-mediated mucosal barrier destruction while reducing inflammation through inhibition of the TLR4-NFκB-pyroptosis signaling pathway in macrophages. BCF-01 is a promising alternative to traditional triple therapy for H. pylori infections, offering minimal side effects with high suitability for high-risk individuals.

Anti-Helicobacter pylori activity and gastroprotective effects of human stomach-derived Lactobacillus paragasseri strain LPG-9

The eradication of Helicobacter pylori is an urgent global issue. However, the traditional regimens have several limitations. Thus, we propose the idea of treating bacterial gastric disease with the objective of eliminating gastric pathogenic bacteria and enhancing gastroprotective effects using gastric probiotics. In this study, a total of 12 Lactobacillus strains were isolated from the gastric mucosa of healthy donors. After evaluation using a weight scoring system, Lactobacillus paragasseri strain LPG-9 was identified as the most promising probiotic for gastric disease, with the highest acid-resistance and the best adhesion characteristics. Gastric colonisation, H. pylori inhibition, anti-inflammatory, and gastric homeostasis effects of LPG-9 were confirmed in C57BL/6 mice. Finally, a safety evaluation and whole-genome sequencing were performed. Based on the results of this study, LPG-9 originates from the gastric microbiota and is a promising probiotic for gastric disease, particularly H. pylori-induced gastritis, providing a solution to this global issue.

Unraveling Impacts of Chamber-Specific Differences in Intercalated Disc Ultrastructure and Molecular Organization on Cardiac Conduction

BACKGROUND

Propagation of action potentials through the heart coordinates the heartbeat. Thus, intercalated discs, specialized cell-cell contact sites that provide electrical and mechanical coupling between cardiomyocytes, are an important target for study. Impaired propagation leads to arrhythmias in many pathologies, where intercalated disc remodeling is a common finding, hence the importance and urgency of understanding propagation dependence on intercalated disc structure. Conventional modeling approaches cannot predict changes in propagation elicited by perturbations that alter intercalated disc ultrastructure or molecular organization, because of lack of quantitative structural data at subcellular through nano scales.

OBJECTIVES

This study sought to quantify intercalated disc structure at these spatial scales in the healthy adult mouse heart and relate them to chamber-specific properties of propagation as a precursor to understanding the effects of pathological intercalated disc remodeling.

METHODS

Using super-resolution light microscopy, electron microscopy, and computational image analysis, we provide here the first ever systematic, multiscale quantification of intercalated disc ultrastructure and molecular organization.

RESULTS

By incorporating these data into a rule-based model of cardiac tissue with realistic intercalated disc structure, and comparing model predictions of electrical propagation with experimental measures of conduction velocity, we reveal that atrial intercalated discs can support faster conduction than their ventricular counterparts, which is normally masked by interchamber differences in myocyte geometry. Further, we identify key ultrastructural and molecular organization features underpinning the ability of atrial intercalated discs to support faster conduction.

CONCLUSIONS

These data provide the first stepping stone to elucidating chamber-specific effects of pathological intercalated disc remodeling, as occurs in many arrhythmic diseases.

Hypofibrinogenemia is an independent predictor of hemophagocytic lymphohistiocytosis in children with sepsis

Hemophagocytic lymphohistiocytosis (HLH) is a potentially life-threatening condition in children with sepsis. We herein aimed to identify clinical and laboratory predictors of HLH in children with sepsis. We conducted a retrospective study of 568 children with sepsis admitted to Guangdong Women and Children Hospital from January 2019 to June 2022. HLH, while rare (6.34%), proved to be a highly fatal complication (37.14%) in children with sepsis. Children with HLH had higher levels of aspartate aminotransferase, lactate dehydrogenase, triglycerides, and ferritin than children without HLH; conversely, they displayed decreased levels of neutrophils, hemoglobin, platelets, fibrinogen, and albumin. Additionally, the HLH group showed higher rates of prolonged fever (> 10 days), hepatomegaly, and splenomegaly than the non-HLH group. Our retrospective analysis identified hypofibrinogenemia (OR = 0.440, P = 0.024) as an independent predictor for the development of HLH in patients with sepsis. The optimal cutoff value for fibrinogen was found to be < 2.43 g/L. The area under the curve for diagnosing HLH was 0.80 (95% confidence interval: 0.73-0.87, P < 0.0001), with a sensitivity of 72.41% and specificity of 76.27%. Thus, hypofibrinogenemia emerges as a potentially valuable predictor for HLH in children with sepsis.

Prenatal diagnosis of Down syndrome combined with transient abnormal myelopoiesis in foetuses with a GATA1 gene variant: two case reports

BACKGROUND

Down syndrome myeloid hyperplasia includes transient abnormal myelopoiesis (TAM) and the myeloid leukemia associated with Down syndrome (ML-DS). The mutation of GATA1 gene is essential in the development of Down syndrome combined with TAM or ML-DS. Some patients with TAM are asymptomatic and may also present with severe manifestations such as hepatosplenomegaly and hydrops.

CASE PRESENTATION

We report two cases of prenatally diagnosed TAM. One case was a rare placental low percentage 21 trisomy mosiacism, resulting in the occurrence of a false negative NIPT. The final diagnosis was made at 36 weeks of gestation when ultrasound revealed significant enlargement of the foetal liver and spleen and an enlarged heart; the foetus eventually died in utero. We detected a placenta with a low percentage (5-8%) of trisomy 21 mosiacism by Copy Number Variation Sequencing (CNV-seq) and Fluorescence in situ hybridization (FISH). In another case, foetal oedema was detected by ultrasound at 31 weeks of gestation. Two foetuses were diagnosed with Down syndrome by chromosomal microarray analysis via umbilical vein puncture and had significantly elevated cord blood leucocyte counts with large numbers of blasts. The GATA1 Sanger sequencing results suggested the presence of a [NM_002049.4(GATA1):c.220G > A (p. Val74Ile)] hemizygous variant and a [NM_002049.4(GATA1):c.49dupC(p. Gln17ProfsTer23)] hemizygous variant of the GATA1 gene in two cases.

CONCLUSION

It seems highly likely that these two identified mutations are the genetic cause of prenatal TAM in foetuses with Down syndrome.

Liquid biopsies for cancer: From bench to clinic

Over the past two decades, liquid biopsy has been increasingly used as a supplement, or even, a replacement to the traditional biopsy in clinical oncological practice, due to its noninvasive and early detectable properties. The detections can be based on a variety of features extracted from tumor‑derived entities, such as quantitative alterations, genetic changes, and epigenetic aberrations, and so on. So far, the clinical applications of cancer liquid biopsy mainly aimed at two aspects, prediction (early diagnosis, prognosis and recurrent evaluation, therapeutic response monitoring, etc.) and intervention. In spite of the rapid development and great contributions achieved, cancer liquid biopsy is still a field under investigation and deserves more clinical practice. To better open up future work, here we systematically reviewed and compared the latest progress of the most widely recognized circulating components, including circulating tumor cells, cell-free circulating DNA, noncoding RNA, and nucleosomes, from their discovery histories to clinical values. According to the features applied, we particularly divided the contents into two parts, beyond epigenetics and epigenetic-based. The latter was considered as the highlight along with a brief overview of the advances in both experimental and bioinformatic approaches, due to its unique advantages and relatively lack of documentation.

Screening and Identification of Probiotic Lactobacilli from the Infant Gut Microbiota to Alleviate Lead Toxicity

Lead (Pb2+) exposure cause a potential hazard to human health and the ecological environment; however, prevention and treatment of Pb2+ toxicity remain problems. The aim of this study is to isolate a novel probiotic lead (Pb2+)-resistant Lactobacillus strain from the infant gut microbiota and to determine whether they have the probiotic properties and investigate its preventive and therapeutic effects in the early-life Pb2+ exposure mouse model. In the present study, a total of 64 Pb2+-resistant colonies were isolated from the infant gut microbiota. Of these colonies, SYF-08, identified as Lacticaseibacillus casei, exhibited a Pb2+-binding capacity and Pb2+ tolerance. The in vivo study showed that SYF-08 treatment could effectively reduce Pb2+ levels in the blood, alleviate Pb2+ enrichment in bone and brain tissues, and recover the intestinal and brain damage in both dams and offspring. SYF-08 treatment also improved the antioxidant index in the liver and kidney tissues, while increasing the diversity of the intestinal microbiota of the offspring. The results of the in vitro and in vivo studies suggest that SYF-08, isolated from infant fecal samples, is a promising candidate probiotic against Pb2+ toxicity.

[Risk factors analysis and prediction model construction of submucosal deep infiltration of early colorectal tumor]

Objective: To investigate the risk factors for the development of deep infiltration in early colorectal tumors (ECT) and to construct a prediction model to predict the development of deep infiltration in patients with ECT. Methods: The clinicopathological data of ECT patients who underwent endoscopic treatment or surgical treatment at the Cancer Hospital, Chinese Academy of Medical Sciences from August 2010 to December 2020 were retrospectively analyzed. The independent risk factors were analyzed by multifactorial regression analysis, and the prediction models were constructed and validated by nomogram. Results: Among the 717 ECT patients, 590 patients were divided in the within superficial infiltration 1 (SM1) group (infiltration depth within SM1) and 127 patients in the exceeding SM1 group (infiltration depth more than SM1). There were no statistically significant differences in gender, age, and lesion location between the two groups (P>0.05). The statistically significant differences were observed in tumor morphological staging, preoperative endoscopic assessment performance, vascular tumor emboli and nerve infiltration, and degree of tumor differentiation (P<0.05). Multivariate regression analysis showed that only erosion or rupture (OR=4.028, 95% CI: 1.468, 11.050, P=0.007), localized depression (OR=3.105, 95% CI: 1.584, 6.088, P=0.001), infiltrative JNET staging (OR=5.622, 95% CI: 3.029, 10.434, P<0.001), and infiltrative Pit pattern (OR=2.722, 95% CI: 1.347, 5.702, P=0.006) were independent risk factors for the development of deep submucosal infiltration in ECT. Nomogram was constructed with the included independent risk factors, and the nomogram was well distinguished and calibrated in predicting the occurrence of deep submucosal infiltration in ECT, with a C-index and area under the curve of 0.920 (95% CI: 0.811, 0.929). Conclusion: The nomogram prediction model constructed based on only erosion or rupture, local depression, infiltrative JNET typing, and infiltrative Pit pattern has a good predictive efficacy in the occurrence of deep submucosal infiltration in ECT.

Soluble CD80 oral delivery by recombinant Lactococcus suppresses tumor growth by enhancing antitumor immunity

CD80 is an important co-stimulatory molecule that participates in the immune response. Soluble CD80 can induce T cell activation and overcome PDL1-mediated immune suppression. In this study, we aimed to construct recombinant Lactococcus lactis for oral delivery of the soluble CD80 (hsCD80) protein or the fusion protein containing the cholera toxin B subunit (CTB) and hsCD80 (CTB-hsCD80) under the control of the nisin-inducible expression system. The recombinant L. lactis expressed and secreted hsCD80 or CTB-hsCD80 fusion proteins after induction by nisin in vitro and in the enteric cavity. Additionally, the CTB-hsCD80 fusion protein showed uptake by intestinal epithelial cells, was cleaved by the furin protease, and was released as free hsCD80 protein into the blood circulation. Orally administered hsCD80 and CTB-hsCD80 containing L. lactis increased the proportion of activated T cells in the spleen and intestinal epithelium, inhibited tumor growth, and prolonged the survival of tumor-bearing mice. The hsCD80-containing L. lactis showed greater therapeutic effects on primary colonic adenoma in APC^min/- mice and completely suppressed tumor growth. Further, recombinant CTB-hsCD80 in L. lactis was more efficient than hsCD80-containing bacteria in inhibiting the growth of xenografted colon cancer and melanoma cells. hsCD80 engineered probiotics may serve as a promising new approach for antitumor immunotherapy, especially for colorectal cancer.

[Clinical efficacy and safety analysis of 125I seed implantation in the treatment of mediastinal lymph node metastasis of lung cancer]

Objective: To investigate the clinical efficacy and safety of ¹²⁵I seed implantation in the treatment of mediastinal lymph node metastasis of lung cancer. Methods: Clinical data of 36 patients who underwent CT-guided ¹²⁵I seed implantation for mediastinal lymph node metastasis of lung cancer from August 2013 to April 2020 in three hospitals of the Northern radioactive particle implantation treatment collaboration group were retrospectively collected, including 24 males and 12 females, aged 46 to 84 years. Cox regression model was used to analyze the relationship between local control rate, survival rate and tumor stage, pathological type, postoperative D90, postoperative D100 and other variables, and to analyze the occurrence of complications. Results: The objective response rate of CT-guided ¹²⁵I seed implantation in the treatment of mediastinal lymph node metastasis of lung cancer was 75% (27/36), the median control time was 12 months, the 1-year local control rate was 47.2% (17/36), and the median survival time was 17 months. The 1-year and 2-year survival rates were 61.1% (22/36) and 22.2% (8/36) respectively. Univariate analysis showed that in the treatment of mediastinal lymph node metastasis with CT-guided ¹²⁵I implantation, factors related to local control included tumor stage (HR=5.246, 95%CI: 2.243-12.268, P<0.001), postoperative D90 (HR=0.191, 95%CI: 0.085-0.431, P<0.001), postoperative D100 (HR=0.240, 95%CI: 0.108-0.533, P<0.001); The factors affecting survival were tumor stage (HR=2.712, 95%CI: 1.356-5.425, P=0.005), postoperative D90 (HR=0.110, 95%CI: 0.041-0.294, P<0.001), postoperative D100 (HR=0.212, 95%CI: 0.092-0.489, P<0.001). Multivariate analysis showed that tumor stage (HR=5.305, 95%CI: 2.187-12.872, P<0.001) and postoperative D100 (HR=0.237, 95%CI: 0.099-0.568, P<0.001) were correlated with local control rate. Tumor stage (HR=2.347, 95%CI: 1.095-5.032, P=0.028) and postoperative D90 (HR=0.144, 95%CI: 0.051-0.410, P<0.001) were correlated with survival. In terms of complications, 9 of the 36 patients had pneumothorax, and 1 of them was cured by closed thoracic drainage for severe pneumothorax; 5 cases developed pulmonary hemorrhage and 5 cases developed hemoptysis, which recovered after hemostasis treatment. One case developed pulmonary infection and recovered after anti-inflammatory treatment. No radiation esophagitis and radiation pneumonia occurred; No grade 3 or higher complications occurred. Conclusion: ¹²⁵I seed implantation in the treatment of lung cancer mediastinal lymph node metastasis has a high local control rate and controllable adverse effects.

Bacteroides dorei BDX-01 alleviates DSS-induced experimental colitis in mice by regulating intestinal bile salt hydrolase activity and the FXR-NLRP3 signaling pathway

Background: The relationships among intestinal dysbiosis, bile acid (BA) metabolism disorders, and ulcerative colitis pathogenesis are now recognized. However, how specific strains regulate BA metabolism to alleviate colitis is still unclear. This study investigated the effects of Bacteroides dorei on the development of acute colitis and elucidated the underlying mechanisms. Methods: The safety of BDX-01 was evaluated in vitro and in vivo. 2.5% dextran sulfate sodium (DSS) induced colitis in C57BL/6 mice, Caco-2, and J774A.1 cells were used to evaluate the anti-inflammatory effect of BDX-01. qPCR and Western blotting were used to detect the expression of inflammatory pathways. Microbiota composition was analyzed by 16S rRNA gene sequencing. Enzyme activity analysis and targeted metabolomics were used to analyze fecal bile salt hydrolase (BSH) and BA levels. Antibiotic-induced pseudo-germ-free mice were used to investigate the role of gut microbiota in the alleviation of colitis by BDX-01. Results: We confirmed the safety of novel strain Bacteroides dorei BDX-01 in vitro and in vivo. Oral BDX-01 administration significantly ameliorated the symptoms and pathological damage of DSS-induced acute colitis. Moreoever, 16S rRNA sequencing and enzyme activity analysis showed that BDX-01 treatment increased intestinal BSH activity and the abundance of bacteria harboring this enzyme. Targeted metabolomics revealed that BDX-01 significantly increased intestinal BA excretion and deconjugation. Certain BAs act as FXR agonists. The β-muricholic acid (βMCA): taurine β-muricholic acid (T-βMCA) and cholic acid (CA): taurocholic acid (TCA) ratios and the deoxycholic acid (DCA) level decreased markedly in the colitis models but increased substantially in BDX-01-treated mice. The colonic farnesoid X receptor (FXR) and fibroblast growth factor 15 (FGF15) were upregulated in mice treated with BDX-01. BDX-01 downregulated the expression of colonic proinflammatory cytokines pyrin domain-containing 3 (NLRP3), ASC, cleaved caspase-1, and IL-1β. Antibiotic treatment didn't abolish the protective effect of BDX-01 on colitis. In vitro studies showed TβMCA abolished the effects of BDX-01 on FXR activation and inhibition of the NLRP3 inflammasome activation. Conclusion: BDX-01 improved DSS-induced acute colitis by regulating intestinal BSH activity and the FXR-NLRP3 signaling pathway. Our findings indicate that BDX-01 is a promising probiotic to improve the management of ulcerative colitis.

PERK/ATF3-Reduced ER Stress on high potassium environment in the suppression of tumor ferroptosis

Potassium (K⁺) is a vital intracellular cation. In the human body, it regulates membrane potential, electrical excitation, protein synthesis, and cell death. Recent studies revealed that dying cancer cells release potassium into the tumor microenvironment (TME), thereby influencing cell survival-related events. Several investigations reported that potassium channels and high potassium levels influence apoptosis. Increasing extracellular potassium and inhibiting K⁺ efflux channels significantly block the apoptotic machinery. However, it is unknown whether a high-potassium environment also affects other types of cell death such as ferroptosis. In the present study, cell counting kit (CCK-8), colony formation ability, and 5-ethynyl-2'-deoxyuridine (EdU) assays demonstrated that a high-potassium environment reverses erastin-induced ferroptosis. RNA sequencing (RNA-Seq) and Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analyses indicated that high potassium levels attenuated the unfolded protein response that is characteristic of endoplasmic reticulum (ER) stress. The ER transmembrane proteins PRKR-like ER kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6) are recognized as ER stress sensors. Here, the PERK blocker GSK2606414 significantly rescued ferroptosis. The present work also disclosed that the ER-related gene activating transcription factor 3 (ATF3) played a vital role in regulating ferroptosis in a high-potassium environment. The foregoing results revealed the roles of potassium and the TME in cancer cell ferroptosis and provided a potential clinical therapeutic strategy for cancer.

[Risk factors for residual cancer or lymph node metastasis after endoscopic noncurable resection of early colorectal cancer]

Objective: Risk factors related to residual cancer or lymph node metastasis after endoscopic non-curative resection of early colorectal cancer were analyzed to predict the risk of residual cancer or lymph node metastasis, optimize the indications of radical surgical surgery, and avoid excessive additional surgical operations. Methods: Clinical data of 81 patients who received endoscopic treatment for early colorectal cancer in the Department of Endoscopy, Cancer Hospital, Chinese Academy of Medical Sciences from 2009 to 2019 and received additional radical surgical surgery after endoscopic resection with pathological indication of non-curative resection were collected to analyze the relationship between various factors and the risk of residual cancer or lymph node metastasis after endoscopic resection. Results: Of the 81 patients, 17 (21.0%) were positive for residual cancer or lymph node metastasis, while 64 (79.0%) were negative. Among 17 patients with residual cancer or positive lymph node metastasis, 3 patients had only residual cancer (2 patients with positive vertical cutting edge). 11 patients had only lymph node metastasis, and 3 patients had both residual cancer and lymph node metastasis. Lesion location, poorly differentiated cancer, depth of submucosal invasion ≥2 000 μm, venous invasion were associated with residual cancer or lymph node metastasis after endoscopic (P<0.05). Logistic multivariate regression analysis showed that poorly differentiated cancer (OR=5.513, 95% CI: 1.423, 21.352, P=0.013) was an independent risk factor for residual cancer or lymph node metastasis after endoscopic non-curative resection of early colorectal cancer. Conclusions: For early colorectal cancer after endoscopic non-curable resection, residual cancer or lymph node metastasis is associated with poorly differentiated cancer, depth of submucosal invasion ≥2 000 μm, venous invasion and the lesions are located in the descending colon, transverse colon, ascending colon and cecum with the postoperative mucosal pathology result. For early colorectal cancer, poorly differentiated cancer is an independent risk factor for residual cancer or lymph node metastasis after endoscopic non-curative resection, which is suggested that radical surgery should be added after endoscopic treatment.

Unraveling Chamber-specific Differences in Intercalated Disc Ultrastructure and Molecular Organization and Their Impact on Cardiac Conduction

During each heartbeat, the propagation of action potentials through the heart coordinates the contraction of billions of individual cardiomyocytes and is thus, a critical life process. Unsurprisingly, intercalated discs, which are cell-cell contact sites specialized to provide electrical and mechanical coupling between adjacent cardiomyocytes, have been the focus of much investigation. Slowed or disrupted propagation leads to potentially life-threatening arrhythmias in a wide range of pathologies, where intercalated disc remodeling is a common finding. Hence, the importance and urgency of understanding intercalated disc structure and its influence on action potential propagation. Surprisingly, however, conventional modeling approaches cannot predict changes in propagation elicited by perturbations that alter intercalated disc ultrastructure or molecular organization, owing to lack of quantitative structural data at subcellular through nano scales. In order to address this critical gap in knowledge, we sought to quantify intercalated disc structure at these finer spatial scales in the healthy adult mouse heart and relate them to function in a chamber-specific manner as a precursor to understanding the impacts of pathological intercalated disc remodeling. Using super-resolution light microscopy, electron microscopy, and computational image analysis, we provide here the first ever systematic, multiscale quantification of intercalated disc ultrastructure and molecular organization. By incorporating these data into a rule-based model of cardiac tissue with realistic intercalated disc structure, and comparing model predictions of electrical propagation with experimental measures of conduction velocity, we reveal that atrial intercalated discs can support faster conduction than their ventricular counterparts, which is normally masked by inter-chamber differences in myocyte geometry. Further, we identify key ultrastructural and molecular organization features underpinning the ability of atrial intercalated discs to support faster conduction. These data provide the first stepping stone to elucidating chamber-specific impacts of pathological intercalated disc remodeling, as occurs in many arrhythmic diseases.

Activation of Ca transport in cardiac microsomes enriches functional sets of ER and SR proteins

The importance of sarcoplasmic reticulum (SR) Ca-handling in heart has led to detailed understanding of Ca-release and re-uptake protein complexes, while less is known about other endoplasmic reticulum (ER) functions in the heart. To more fully understand cardiac SR and ER functions, we analyzed cardiac microsomes based on their increased density through the actions of the SR Ca-ATPase (SERCA) and the ryanodine receptor that are highly active in cardiomyocytes. Crude cardiac microsomal vesicles loaded with Ca oxalate produced two higher density subfractions, MedSR and HighSR. Analyses of protein enrichments from the 3 membrane preparations (crude microsomes, MedSR, and HighSR), showed that only a third of microsomal proteins in heart, or 354 proteins, were enriched ≥2.0-fold in SR. Previously studied SR proteins were all enriched, as were proteins associated with canonical ER functions. Contractile, mitochondrial, and sarcolemmal proteins were not enriched. Comparing the levels of SERCA-positive SR proteins in MedSR versus HighSR vesicles produced a range of SR subfraction enrichments signifying differing levels of Ca leak (ryanodine receptor) co-localized in the same membrane patch. All known junctional SR proteins were more enriched in MedSR, while canonical ER proteins were more enriched in HighSR membrane. Proteins from other putative ER/SR subdomains also showed characteristic distributions among SR subpopulations. We conclude that active Ca loading of cardiac microsomes, reflecting the combined activities of Ca uptake by SERCA, and Ca leak by RyR, permits evaluation of multiple functional ER/SR subdomains. Sets of proteins from these subdomains exhibited similar enrichment patterns across membrane subfractions, reflecting the relative levels of SERCA and RyR present within individual patches of cardiac ER and SR.

Systematic literature review of solar-powered landfill leachate sanitation: Challenges and research directions over the past decade

Researchers have documented the negative effects of refractory chemicals and emergent pollutants in landfill leachate (LL) that cannot be degraded using conventional methods. The propagation, invasion, and deleterious effects of several LL hazards affect aquatic species, the environment, and food outlets, causing significant safety issues. These include cancer risks, chronic exposure, and reproductive consequences. Alternatively, solar energy is a sustainable solution for treating landfill leachate to benefit humans and the environment. In this work, a thorough bibliometric and systematic analysis of studies that employed solar energy for landfill leachate remediation over the past decade was conducted in order to determine trends, and future research areas. In addition to the energy demand, the economic aspect and the advantages of using solar power to treat landfill leachate were discussed. Additionally, the study gives specific suggestions for future research purposes and important problems. The reviewed literature revealed that combining solar-based physical-chemical and biological processes has proven to be the most efficient method for landfill leachate degradation. It also appears from the bibliometric study that more collaboration and contribution are needed to develop solar-based landfill leachate treatment. This study concludes that solar-powered landfill leachate remediation techniques would considerably increase the effectiveness of treated leachate reutilization, advancing the cause of environmental sustainability.

[Plasmids carried by carbapenems-resistant Klebsiella pneumoniae in burn patients and its correlation with strain transmission]

Objective: To explore the carrier status of carbapenems-resistant Klebsiella pneumoniae (CRKP) plasmids in burn patients and analyze the correlation of these plasmids with the transmission of CRKP. Methods: A retrospective observational study was conducted. A total of 26 CRKP strains, which were isolated from the clinic-related samples of 22 burn patients (with 20 males and 2 females, aged (42±16) years) admitted to the First Affiliated Hospital of Army Medical University (the Third Military Medical University) from January to December 2017, were collected and individually numbered. The plasmids of the strains were extracted by alkali lysis. After determination of the plasmid concentration by a nucleic acid concentration detector, the agarose gel electrophoresis was used to visualize the bands, and rough plasmids typing was performed. The plasmid of the smallest numbered CRKP in each plasmid type was transformed into competent Escherichia coli (E. coli) strain Top10 (hereinafter referred to as TOP10 strain). The growth of each transformed strains and a Top10 strain cultivated in ampicillin containing Luria-Bertani (LB) agar medium overnight was observed, and the proportion of successful transformation was calculated. The plasmids from the smallest numbered plasmid carrying CRKP strain of successfully transformed Top10 strains (hereinafter referred to as the smallest successfully transformed strain) and correspondingly numbered CRKP were extracted, and then, the agarose gel electrophoresis was used to visualize the bands. Aforementioned successfully transformed strains and a TOP10 strain were used for the antimicrobial susceptibility testing with 17 antibiotics commonly used in clinic. The plasmid from the smallest successfully transformed strain was sequenced using the next-generation sequencing technology. Bioinformatics analyses such as protein-coding gene prediction and protein sequence alignment were performed successively. The sequence was subsequently named pKP03-NDM1 according to the carrying of drug resistance gene. According to the whole genome sequence of the plasmid carried by the smallest successfully transformed strain, the polymerase chain reaction, agarose gel electrophoresis, and gene sequencing were used to detect the New Delhi metallo-beta lactamase-1 (blaNDM-1) of plasmids in the remaining 25 strains of CRKP. The ST typing in multilocus sequence typing of 26 strains of CRKP was analyzed based on the literature. Results: Plasmids were successfully extracted from 26 CRKP, with mass concentrations ranging from 19.3 to 189.8 ng/μL. Each of the 26 CRKP carrying plasmids showed at least one band longer than 2 500 bp in the agarose gel electrophoresis, which were roughly divided into 6 patterns of A, B, C, D, E, and F. After overnight cultivation, no growth of strains was observed in LB agar medium containing ampicillin inoculated with the TOP10 strain or TOP10 strains transformed by the plasmid of CRKP patterning A, B, D, or E. In contrast, TOP10 strains transformed by the pattern C plasmid from NO.3 CRKP and the pattern F plasmid from NO.15 CRKP resulted in numerous colony growths, and those transformed strains were named as TOP10-pKP03 and TOP10-pKP15, respectively. The proportion of successful transformation was 1/3. The plasmid carried by TOP10-pKP03 showed a single band in the agarose gel electrophoresis, which was the same size as the largest band of the plasmid from NO.3 CRKP. The TOP10 strain was sensitive to the 17 antibiotics commonly used in clinic. TOP10-pKP03 and TOP10-pKP15 were resistant to penicillins, cephalosporins, and carbapenems but remained sensitive to monocyclic β-lactam, aminoglycosides, quinolones and tigecycline. The full length of the plasmid carried by TOP10-pKP03 was 41 190 bp. In addition to blaNDM-1, this plasmid carried bleMBL, T4SS, bleomycin resistance gene, conjugation transfer elements, and relaxase, etc. The plasmid showed 99% nucleotide identity similarity and the same length to the plasmid pJN24NDM1 extracted from an E. coli isolate JN24. Totally 16 (61.5%) CRKP were confirmed to carrying blaNDM-1 gene, among the ST typing of the 16 strains, 11 strains were ST11, while ST215, ST260, ST395, ST2230, and new ST had 1 strain each. Among the ST typing of 10 blaNDM-1-negative CRKP, 8 strains were ST11, while ST395 and ST2230 had 1 strain each. Conclusions: A blaNDM-1 gene carrying plasmid pKP03-NDM1 was extracted and sequenced from CRKP isolated from burn patients, with a high plasmid carrying rate. Meanwhile, this plasmid may mediate inter-CRKP and CRKP-E. coli horizontal transfer of blaNDM-1, leading to transmission of antimicrobial resistance.

Testosterone does not shorten action potential duration in Langendorff-perfused rabbit ventricles

BACKGROUND

Women have longer baseline QT intervals than men. Because previous studies showed that testosterone and 5α-dihydrotestosterone shorten the ventricular action potential duration (APD) in animal models, differential testosterone concentrations may account for the sex differences in QT interval.

OBJECTIVE

The purpose of this study was to test the hypothesis that testosterone shortens the APD in Langendorff-perfused rabbit ventricles.

METHODS

We performed optical mapping studies in hearts with or without testosterone administration. Acute studies included 26 hearts using 2 different protocols, including 17 without and 9 with atrioventricular (AV) block. For chronic studies, we implanted testosterone pellets subcutaneously in 7 female rabbits for 2-3 weeks before optical mapping studies during complete AV block. Six rabbits without pellet implantation served as controls.

RESULTS

The hearts in the acute studies were paced with a pacing cycle length (PCL) of 200-300 ms and mapped at baseline and after administration of 1 nM, 10 nM, 100 nM, and 3 μM of testosterone. There was no shortening of APD80 at any PCL. Instead, a lengthening of APD80 was noted at higher concentrations. There were no sex differences in testosterone responses. In chronic studies, heart rates were 136 ± 5 bpm before and 148 ± 9 bpm after (P = .10) while QTc intervals were 314 ± 9 ms before and 317 ± 99 ms after (P = .69) testosterone pellet implantation, respectively. Overall, ventricular APD80 in the pellet group was longer than in the control group at 300- to 700-ms PCL.

CONCLUSION

Testosterone does not shorten ventricular repolarization in rabbit hearts.

[Screening, functional analysis and clinical validation of differentially expressed genes in diabetic foot ulcers]

Objective: To screen the differentially expressed genes (DEGs) in diabetic foot ulcers (DFUs), and to perform functional analysis and clinical validation of them, intending to lay a theoretical foundation for epigenetic therapy of chronic refractory wounds. Methods: An observational study was conducted. The gene expression profile dataset GSE80178 of DFU patients in Gene Expression Omnibus (GEO) was selected, and the DEG between three normal skin tissue samples and six DFU tissue samples in the dataset was analyzed and screened using the GEO2R tool. For the screened DEG, ClusterProfiler, org.Hs.eg.db, GOplot, and ggplot2 in the R language packages were used for Gene Ontology (GO) enrichment analysis of biological processes, molecular functions, and cellular components, and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, respectively. Protein-protein interaction (PPI) analysis was performed using STRING database to screen key genes in the DEG, and GO enrichment analysis of key genes was performed using Cytohubba plug-in in Cytoscape 3.9.1 software. DFU tissue and normal skin tissue discarded after surgery were collected respectively from 15 DFU patients (7 males and 8 females, aged 55-87 years) and 15 acute wound patients (6 males and 9 females, aged 8-52 years) who were admitted to Xiang'an Hospital of Xiamen University from September 2018 to March 2021. The mRNA and protein expressions of small proline-rich repeat protein 1A (SPRR1A) and late cornified envelope protein 3C (LCE3C) were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction and immunohistochemistry, respectively. Data were statistically analyzed with independent sample t test. Results: Compared with normal skin tissue, 492 statistically differentially expressed DEGs were screened from DFU tissue of DFU patients (corrected P<0.05 or corrected P<0.01), including 363 up-regulated DEGs and 129 down-regulated DEGs. GO terminology analysis showed that DEGs were significantly enriched in the aspects of skin development, keratinocyte (KC) differentiation, keratinization, epidermal development, and epidermal cell differentiation, etc. (corrected P values all <0.01). KEGG pathway analysis showed that DEGs were significantly enriched in the aspects of tumor-associated microRNA, Ras related protein 1 signaling pathway, and pluripotent stem cell regulatory signaling pathway, etc. (corrected P values all <0.01). PPI analysis showed that endophial protein, SPRR1A, SPRR1B, SPRR2B, SPRR2E, SPRR2F, LCE3C, LCE3E, keratin 16 (all down-regulated DEGs), and filoprotein (up-regulated DEG) were key genes of DEGs screened from DFU tissue of DFU patients, which were significantly enriched in GO terms of keratinization, KC differentiation, epidermal cell differentiation, skin development, epidermis development, and peptide cross-linking, etc. (corrected P values all <0.01). The mRNA expressions of SPRR1A and LCE3C in DFU tissue of DFU patients were 0.588±0.082 and 0.659±0.098, respectively, and the protein expressions were 0.22±0.05 and 0.24±0.04, respectively, which were significantly lower than 1.069±0.025 and 1.053±0.044 (with t values of 20.91 and 13.66, respectively, P values all <0.01) and 0.38±0.04 and 0.45±0.05 (with t values of 9.69 and 12.46, respectively, P values all <0.01) in normal skin tissue of acute wound patients. Conclusions: Compared with normal skin tissue, there is DEG profile in DFU tissue of DFU patients, with DEGs being significantly enriched in the aspects of KC differentiation and keratin function. Key DEGs are related to the biological function of KC, and their low expressions in DFU tissue of DFU patients may impede ulcer healing.

Surface Modification of TiO2 Nanotubes Prepared by Porous Titanium Anodization via Hydrothermal Reaction: A Method for Synthesis High-Efficiency Adsorbents of Recovering Sr Ions

The recycling of strontium ions (Sr²⁺) from sea water has been well known for its good cost-effectiveness and environment friendliness. Herein, we modified the surface of TiO₂ nanotubes (TNTs) prepared by porous titanium anodization via hydrothermal (HT) reaction and synthesized a highly efficient adsorbent for the repeated recycling of Sr²⁺. TNTs with a high specific surface area were manufactured on porous titanium by internal anodic oxidation. The as-prepared TNTs were treated by HT method to synthesize adsorption materials with a tubular bottom and grass-type top structure loaded with Na⁺. The surface cracks were eliminated by annealing pretreatment, and the investigation found that the 6 h HT reaction most effectively increased the Na⁺ content in the adsorbent. The as-synthesized adsorbents (HT-6TNTs) were used to recover Sr²⁺, and the maximum adsorption efficiency (approximately 100%) and adsorption equilibrium were observed within 10 h. Meanwhile, three consecutive cycles of adsorption experiments proved the uniform behavior of the HT-6TNTs in the reproducible recycling of Sr²⁺. In addition, by increasing the anodization time of TNTs from 0.5 to 3 h, the maximum adsorption capacity can be increased from 4.68 to 36.15 mg·unit^-1, approximately 7.7 times higher.

[Research advances on interleukin-6 in hypertrophic scar formation]

Hypertrophic scar is a pathological repair result of excessive accumulation of extracellular matrix after skin damage, which affects the appearance and function of patients with varying degrees. The degree of scar formation is directly related to the strength of inflammatory reaction during wound healing, and excessive or prolonged inflammatory response increases the incidence of hypertrophic scars. Interleukin-6 (IL-6) is a pleiotropic cytokine that is involved in regulating the fibrotic network composed of fibroblasts, macrophages, keratinocytes, and vascular endothelial cells, and is closely related to the formation of hypertrophic scars. This article reviews the role of IL-6 and its signaling pathway in hypertrophic scar formation.

[Phenotypes and genotypes of 78 patients with propionic acidemia]

Objective: Propionic acidemia is a rare inherited metabolic disorder caused by propionyl CoA carboxylase (PCC) deficiency. This study aims to analyze the clinical characteristics and gene variations of Chinese patients with propionic acidemia, and to explore the correlation between clinical phenotypes and genotypes. Methods: Single-center, retrospective and observational study. Seventy-eight patients of propionic acidemia (46 males and 32 females) from 20 provinces and autonomous regions were admitted from January 2007 to April 2022. Their age of initial diagnosis ranged from 7 days to 15 years. The clinical manifestations, biochemical and metabolic abnormalities, genetic variations, diagnosis, treatment and outcome were studied. Chi-Square test or Mann-Whitney U test were used for statistical analysis. Results: Among 78 cases, 6 (7.7%) were identified by newborn screening; 72 (92.3%) were clinically diagnosed after onset, and the age of onset was 2 hours after birth to 15 years old; 32 cases had early-onset disease and 40 cases had late-onset disease. The initial manifestations included lethargy, hypotonia, vomiting, feeding difficulties, developmental delay, epilepsy, and coma. Among the 74 cases who accepted gene analysis, 35 (47.3%) had PCCA variants and 39 (52.7%) had PCCB variants. A total of 39 PCCA variants and 32 PCCB variants were detected, among which c.2002G>A and c.229C>T in PCCA and c.838dupC and c.1087T>C in PCCB were the most common variants in this cohort. The variants c.1228C>T and c.1283C>T in PCCB may be related to early-onset type. The variants c.838dupC, c.1127G>T and c.1316A>G in PCCB, and c.2002G>A in PCCA may be related to late-onset disease. Six patients detected by newborn screening and treated at asymptomatic stage developed normal. The clinically diagnosed 72 cases had varied complications. 10 (12.8%) cases of them died. 62 patients improved after metabolic therapy by L-carnitine and diet. Six patients received liver transplantation because of recurrent metabolic crisis. Their clinical symptoms were markedly improved. Conclusion: The clinical manifestations of propionic acidemia are complex and lack of specificity. Newborn screening and high-risk screening are keys for early treatment and better outcome. The correlation between the genotype and phenotype of propionic acidemia is unclear, but certain variants may be associated with early-onset or late-onset propionic acidemia.

[The clinical value of multi-target stool fecal immunochemical test-DNA in early screening and diagnosis for colorectal cancer]

Objective: To investigate the clinical diagnostic value of multi-target stool fecal immunochemical test-DNA (FIT-DNA) test in colorectal cancer (CRC) and advanced adenoma (AA). Methods: A total of 235 patients who were undergoing colonoscopy or colorectal cancer surgery in the Cancer Hospital, Chinese Academy of Medical Sciences from April 2021 to January 2022 were prospectively enrolled. There were 141 males and 94 females, with an average age of (55±13) years (22-86). The patients were divided into two groups, including 215 patients who were first diagnosed but not treated (86 cases of CRC, 12 cases of AA, 25 cases of non-advanced adenoma, 8 cases of hyperplastic or other polyps and 84 apparently healthy cases) and 20 patients in the intervention group (2 cases with a history of CRC surgery, 6 cases with a history of endoscopic surgery, 4 non-CRC patients with special diseases and 8 cases with a history of neoadjuvant chemoradiotherapy). Fresh stool samples were collected before intestinal preparation or surgery for FIT-DNA test using the matching kit for sample processing and nucleic acid purification. KRAS mutation and methylation of BMP3 and NDRG4 genes were detected by fluorescence probe method, and FIT method was employed to detect fecal occult blood. Colonoscopy or pathological biopsy results were used as the gold standard. And the screening and diagnostic efficacy of FIT-DNA test for colorectal cancer and advanced adenoma were evaluated by receiver operating curve (ROC). Results: The sensitivity of FIT-DNA test for early colorectal cancer and advanced adenoma was 7/7 and 8/12, respectively. And the negative predictive value was 98.1% (104/106) and 93.7% (104/111), respectively. The overall screening sensitivity for both early colorectal cancer and advanced adenoma was 15/19, and the negative predictive value was 96.3% (104/108). Besides, the area under the curves (AUCs) were 0.982 (95%CI: 0.960-1.000, P<0.05), 0.758 (95%CI: 0.592-0.924, P<0.05) and 0.841 (95%CI: 0.724-0.957, P<0.05), respectively. Moreover, the diagnostic sensitivity of FIT-DNA test was 98.8% (85/86) for colorectal cancer, 8/12 for advanced adenoma, and 94.9% (93/98) for both colorectal cancer and advanced adenoma, with a specificity of 88.9% (104/117). The AUCs were 0.968 (95%CI: 0.937-0.997, P<0.05), 0.758 (95%CI: 0.592-0.924, P<0.05) and 0.942 (95%CI: 0.905-0.979, P<0.05), respectively. After the inclusion of intervention group, the overall diagnostic sensitivity and specificity of FIT-DNA test was 91.6% (98/107) and 89.1% (114/128), respectively. Conclusion: FIT-DNA test has a high early screening and diagnostic efficacy for colorectal cancer.

[Novel MFN2, BSCL2 and LRSAM1 variants in a cohort of Chinese patients with Charcot-Marie-Tooth disease]

Objective: Charcot-Marie-Tooth disease (CMT) comprises a group of clinically and genetically heterogeneous inherited neuropathies with an estimated prevalence of 1 in 2500. This study aimed to analyze the clinical and mutational characteristics of Chinese CMT patients with MFN2, BSCL2 and LRSAM1 variants. Methods: In this study, genetic analysis was performed in 206 Chinese patients at Chinese PLA General Hospital from December 2012 to March 2020 with clinical diagnosis of CMT, and reported variants of MFN2, BSCL2 and LRSAM1 related to CMT2. Results: We reported ten MFN2 mutations in ten unrelated patients (7 male, 3 female), two of whom had positive family history. Three novel mutations were detected including c.475-2A>G (splicing); c.687dupA (p.E230Rfs*16) and c.558dupT (p.S186fs). We reported three BSCL2 mutations of four unrelated patients, including c.461C>G (p.S154W), c.461C>T(p.S154L), and novel variants of c.1309G>C (p.A437P) and c.845C>T (p.A282V). Furthermore, two novel variants of LRSAM1, including c.1930G>T (p.G644C) and c.1178T>A (p.L393Q) were detected in two unrelated patients. Conclusion: Mutational spectrum of MFN2-, BSCL2-and LRSAM1-related CMT disease is expanded with the identification of novel variants in Chinese patients.

Lactobacillus casei SYF-08 Protects Against Pb-Induced Injury in Young Mice by Regulating Bile Acid Metabolism and Increasing Pb Excretion

Pb poisoning affects infant growth and development. However, dimercaptosuccinic acid (DMSA) as the current therapy for Pb poisoning exerts relatively significant toxic side effects in infants. Therefore, identifying a non-toxic treatment in this regard is particularly important. In this study, we aimed to investigate the therapeutic effect of an infant feces-derived probiotic strain, Lactobacillus casei SYF-08 (SYF-08), on Pb poisoning in young mice. The Pb levels in the organisms were detected via inductively coupled plasma mass spectrometry, while the therapeutic effect of SYF-08 on Pb-induced neural system damage was explored via the Morris water maze test, hematoxylin-eosin staining, and immunohistochemistry. Additionally, the molecular mechanisms underlying the protective effects of SYF-08 against Pb-induced intestinal damage were also explored via histological staining, 16S rRNA sequencing, untargeted metabolomics, qRT-PCR, and western blotting. In vivo experiments revealed that SYF-08 reduced blood and bone Pb levels and increased urinary Pb excretion. Additionally, SYF-08 alleviated Pb-induced pathological damage to the brain and ultimately improved the learning and cognitive abilities of the young mice. This treatment also restored intestinal microflora dysbiosis, regulated bile acid metabolism, and inhibited the FXR-NLRP3 signaling pathway. It also resulted in fewer adverse events than the DMSA treatment. In conclusion, our results provided valuable insights into the therapeutic role of SYF-08 in Pb poisoning and also suggested that its administration can significantly alleviate the Pb-induced damage.

Lactobacillus plantarum WSJ-06 alleviates neurobehavioral injury induced by lead in mice through the gut microbiota

Chronic lead exposure can result in cognitive dysfunction and behavioral disorders. However, the current treatments for alleviating lead poisoning have many side effects. Previous studies have suggested that probiotics may have the potential to ameliorate neurotoxicity caused by lead exposure. This study determines the alleviating effects of Lactobacillus plantarum WSJ-06 on neurological disorders induced by chronic lead exposure from the perspective of the gut microbiota and serum metabolites. The results showed that treatment with Lactobacillus plantarum WSJ-06 alleviated memory dysfunction and reduced the levels of inflammatory cytokines in the serum and hippocampus induced by lead exposure. In addition, Lactobacillus plantarum WSJ-06 partially restored the lead-induced gut microbiota dysbiosis. It also increased the proportion of some beneficial metabolites in the serum, such as arachidonic acid, tryptophan hydroxylase, serotonin, vitamin B12, trehalose, and kynurenic acid, and decreased some metabolites in the serum, such as LPS 20:5 and L-kynurenine. A correlation analysis further indicated that lead-induced neurobehavioral disorders were related to intestinal microbiota (the [Eubacterium]_siraeum_group, Roseburia, Lactobacillus, etc) and serum metabolites (LPS 20:5, serotonin, vitamin B12, etc). In conclusion, Lactobacillus plantarum WSJ-06 alleviated neuroinflammation and memory impairment caused by lead exposure by modulating the gut microbiota and metabolites in the serum.

[Prevalence and transmission of pyrazinamide-resistant Mycobacterium tuberculosis in Hunan Province,China]

Objective: To provide a scientific reference for the prevention and treatment of pyrazinamide-resistant tuberculosis (PZA-R TB), we analyzed the prevalence and risk factors of pyrazinamide-resistant tuberculosis in Hunan province and described the genotyping and clustering characteristics of the pyrazinamide-resistant Mycobacterium tuberculosis (PZA-R MTB) isolates. Methods: The drug susceptibility test results of first-line anti-tuberculosis drugs including isoniazid (INH), rifampicin (RFP), streptomycin (SM), ethambutol (EMB) and pyrazinamide (PZA), and the characteristics of patients were collected from 3 862 tuberculosis patients in Hunan Chest Hospital (Institute of Tuberculosis Control and Prevention) from January 2016 to December 2018. The prevalence of PZA-R TB was calculated and risk factors were analyzed by univariate and multivariable logistic regression analysis. Two hundred and twelve Mycobacterium tuberculosis isolates selected from June 2017 to June 2018 were genotyped using the 24-loci MIRU-VNTR system. The genetic difference value (h), and the Hunter-Gaston index (HGI) were used to evaluate the resolution and variation for the 24 loci. MIRU-VNTR results were analyzed using BioNumerics 5.0 software to conduct cluster analysis. Clustered isolates were further analyzed by pncA gene sequencing. Results: The rate of PZA-R TB among tuberculosis patients and MDR patients was 14.7%(566/3 862) and 60.5%(511/844), respectively. Multivariable logistic regression analysis showed that patients who were INH mono-resistance and MDR had a higher risk of developing PZA resistance, compared with TB patients who were pan-sensitive to anti-TB drugs (INH, RFP, SM, and EMB). The adjusted OR value (95%CI) was 13.08(5.67-30.18), 298.41(164.88-540.08), respectively, and P values were all less than 0.01. Clustering analysis showed that 65 strains formed 19 clusters, the clustering rate was 30.7%(65/212). Of 19 clusters, eight clusters had at least two isolates with identical pncA mutation types within each cluster. In eight clusters, cluster 4, 6, 16 had four, three, and two patients who lived in the same county, respectively, thus providing probable epidemiological links for the recent transmission of PZA-R Mycobacterium tuberculosis. At least 47.6%(101/212) of PZA drug-resistant TB patients were suggestive of primary drug resistance caused by transmission. Conclusions: The prevalence of PZA-R TB was severe in Hunan province. PZA susceptibility testing should be performed for isolates resistant to any first-line anti-tuberculosis drugs, especially for MDR-MTB isolates. Nearly half of tuberculosis patients were suggestive of primary drug resistance caused by transmission. The prevention and treatment strategy of PZA-R TB should focus on the standardized treatment and management of patients as well as control of the source of infection.

Intrahepatic Cholestasis of Pregnancy Increases Inflammatory Susceptibility in Neonatal Offspring by Modulating Gut Microbiota

Intrahepatic cholestasis of pregnancy (ICP) is a liver disease of pregnancy that is characterized by increased bile acid levels in maternal serum. Studies have shown that cholestatic pregnancy can result in long-term metabolic disturbances in the offspring. However, how ICP shapes the offspring’s immunity and predisposition to inflammatory disorders at an early stage is unknown. In this study, we investigated the effect of maternal cholestasis on neonatal offspring metabolism and immune function. We compared 71 neonates with ICP mothers and 63 neonates with healthy mothers and found that the incidence of jaundice and infection was significantly higher in ICP offspring. Maternal serum total bile acid level was associated with blood cell counts in full-term ICP offspring. In animal experiments, a compensatory activation of hepatic and ileal farnesoid X receptor (FXR) and altered gut microbiota in the first week were found in ICP offspring. We also investigated lipopolysaccharide (LPS)-induced inflammatory responses in neonatal rats and found that ICP offspring were more susceptible to inflammation. To understand the correlation between congenital abnormal FXR activation and tissue immunity dysregulation, we assessed the effects of the FXR agonist GW4064 and FXR antagonist E/Z-GS in ICP offspring after LPS exposure. The expression of several pro-inflammatory cytokines significantly decreased after treatment with E/Z-GS but increased after treatment with GW4064. Treatment with the probiotic Lactobacillus rhamnosus LRX01 that inhibits FXR expression in the ileum reduced susceptibility to LPS exposure in ICP offspring. The current study indicated that cholestatic pregnancy may increase the susceptibility of the offspring to inflammation by altering bile acid metabolism and gut microbiota at an early stage. We suggest that supplementation with Lactobacillus rhamnosus LRX01, which inhibits FXR expression in the ileum, may improve intestinal immunity in ICP offspring.

[Clinical characteristics and CBS gene analysis of 13 cases with classic homocystinuria]

Objective: To analyze the clinical features and CBS gene variants of 13 patients with classic homocystinuria, and the strategies of individual treatment and prevention were explored. Methods: The general information, clinical manifestations, laboratory tests, cranial images, CBS gene variants, diagnosis and therapeutic strategies of 13 patients with classic homocystinuria admitted to the Department of Pediatrics of Children's Hospital Affiliated to Zhengzhou University and Peking University First Hospital from November 2013 to June 2021 were analyzed retrospectively. Results: There were 13 patients diagnosed at the age of 10 days to 14 years, 6 were male and 7 were female. There were 3 patients detected by newborn screening and received treatment at the asymptomatic stage. There were 10 patients clinically diagnosed at the age of 5 to 14 years. Their symptoms appeared at age of 1 to 6 years. The major clinical manifestations were marfanoid features, lens dislocation and (or) myopia, developmental delay, osteoporosis, and cardiovascular diseases. Brain magnetic resonance imaging showed asymmetric infarcts in 4 patients and hypomyelination in 1 case. Increased blood methionine, plasma total homocysteine and urinary total homocysteine with normal urinary methylmalonic acid were found in 13 patients. The biochemical features were consistent with classic homocystinuria. Totally 18 variants were identified in CBS gene of 13 patients, 10 variants were novel and 8 were reported. only 1 patient was partially responsive to vitamin B₆ treatment, while 12 cases were non-responsive. They were mainly treated with low methionine diet and betaine supplement. Three vitamin B₆ non-responsive cases received liver transplantation at age of 3, 8 and 8 years, respectively. Their blood methionine and total homocysteine returned to normal within a week after liver transplantation. One patient died. Prenatal diagnosis was performed for a fetus when the mother was pregnant again. Two pathogenic CBS gene variants were identified from the amniocytes as same as the proband. Conclusions: The clinical manifestations of classic homocystinuria are complex and variable. Blood amino acid analysis, serum or urine total homocysteine assay and gene analysis are critical for its diagnosis. There were 10 novel CBS gene varients were identified expanding the CBS gene varient spectrum. Liver transplantation is an effective treatment. Prenatal diagnosis is important to prevent classic homocysteinuria.

[Transcriptomic analysis of the ΔPaLoc mutant of Clostridioides difficile and verification of its toxicity]

Objective: Comparative analyses of wild-type Clostridioides difficile 630 (Cd630) strain and pathogenicity locus (PaLoc) knockout mutant (ΔPaLoc) by using RNA-seq technology. Analysis of differential expression of Cd630 wild-type strain and ΔPaLoc mutant strain and measurement of its cellular virulence changes. Lay the foundation for the construction of an toxin-attenuated vaccine strain against Clostridioides difficile. Methods: Analysis of Cd630 and ΔPaLoc mutant strains using high-throughput sequencing (RNA-seq). Clustering differentially expressed genes and screening differentially expressed genes by DESeq software. Further analysis of differential genes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, cytotoxicity assays of ΔPaLoc and Cd630 strains were performed in the African monkey kidney epithelial cell (Vero) and the human colonic cell (Caco-2) lines. Results: The transcriptome data showed that the ΔPaLoc mutant toxin genes tcdA and tcdB were not transcribed. Compared to the wild-type strain, CD630_36010, CD630_020910,CD630_02080 and cel genes upregulated 17.92,11.40,8.93 and 7.55 fold, respectively. Whereas the hom2 (high serine dehydrogenase), the CD630_15810 (spore-forming protein), CD630_23230 (zinc-binding dehydrogenase) and CD630_23240 (galactitol 1-phosphate 5-dehydrogenase) genes were down-regulated by 0.06, 0.075, 0.133 and 0.183 fold, respectively. The GO and KEGG enrichment analyses showed that the differentially transcribed genes in ΔPaLoc were enriched in the density-sensing system, ABC transport system, two-component system, phosphotransferase (PTS) system, and sugar metabolism pathway, as well as vancomycin resistance-related pathways. Cytotoxicity assays showed that the ΔPaLoc mutant strain lost its virulence to Vero and Caco-2 cells compared to the wild-type Cd630 strain. Conclusion: Transcriptional sequencing analysis of the Cd630 and ΔPaLoc mutant strains showed that the toxin genes were not transcribed. Those other differential genes could provide a reference for further studies on the physiological and biochemical properties of the ΔPaLoc mutant strain. Cytotoxicity assays confirmed that the ΔPaLoc mutant lost virulence to Vero and Caco-2 cells, thus laying the foundation for constructing an toxin-attenuated vaccine strain against C. difficile.

[Course of disease and related epidemiological parameters of COVID-19: a prospective study based on contact tracing cohort]

Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.