Synthesis and evaluation of a novel cross-linked biochar/ferric chloride hybrid material for integrated coagulation and adsorption of turbidity and humic acid from synthetic wastewater: Implications for sludge valorisation.

The deep removal of organic pollutants is challenging for coagulation technology in drinking water and wastewater treatment plants to satisfy the rising water standards. Iron (III) chloride (FeCl3) is a popular inorganic coagulant; although it has good performance in removing the turbidity (TB) in water at an alkaline medium, it cannot remove dissolved pollutants and natural organic matter such as humic acid water solution. Additionally, its hygroscopic nature complicates determining the optimal dosage for effective coagulation. Biochar (BC), a popular adsorbent with abundant functional groups, porous structure, and relatively high surface area, can adsorb adsorbates from water matrices. Therefore, combining BC with FeCl3 presents a potential solution to address the challenges associated with iron chloride. Consequently, this study focused on preparing and characterizing a novel biochar/ferric chloride-based coagulant (BC-FeCl3) for efficient removal of turbidity (TB) and natural organic matter, specifically humic acid (HA), from synthetic wastewater. The potential solution for the disposal of produced sludge was achieved by its recovering and recycling, then used in adsorption of HA from aqueous solution. The novel coagulant presented high TB and HA removal within 10 min of settling period at pH solution of 7.5. Furthermore, the recovered sludge presented a good performance in the adsorption of HA from aqueous solution. Adsorption isotherm and kinetics studies revealed that the Pseudo-second-order model best described kinetic adsorption, while the Freundlich model dominated the adsorption isotherm.

Treatment outcomes in patients with Ewing sarcoma of the spine in a resource-challenged setting: 17-year experience from a single center in India.

Ewing sarcoma (ES) of the spine is a rare childhood cancer with sparse literature on treatment outcomes. We aimed to describe survival outcomes and prognostic factors in patients with spinal ES treated at a single institute in a resource-challenged setting. We conducted a retrospective analysis of patients with spinal ES registered at a tertiary care oncology center between 2003-2019. Clinical patient data was retrieved from hospital records. Cox regression analysis was used to identify the association of baseline clinical parameters with event free survival (EFS) and overall survival (OS). A cohort of 85 patients was analyzed including 38 (45%) patients with metastatic disease. The median age was 15 years with 73% being male. Local therapy was administered in 62 (72.9%) patients with surgery alone in 8 (9.4%), radiotherapy alone in 36 (42.4%) and both in 18 (21.2%) patients. A higher proportion of males received local therapy than females (80.3% versus 59.1%; p = 0.049). The median EFS and OS were 20.1 and 28.6 months, respectively. On univariable analysis, age ≤ 15 years, female sex, serum albumin ≤3.5 g/dL and hemoglobin ≤11 g/dL were associated with inferior EFS while younger age, female sex, hypoalbuminemia and metastatic disease were associated with inferior OS. On multivariable analysis, only hypoalbuminemia was predictive for inferior EFS (HR:2.41; p = 0.005) while hypoalbuminemia (HR:2.06;p = 0.033) and female sex (HR:1.83; p = 0.046) were associated with inferior OS. We concluded that hypoalbuminemia confers poor prognosis in ES spine. Survival outcomes are poorer in females treated in our setting, possibly due to prevailing sex-based biases.

Robust Mutual Synchronization in Long Spin Hall Nano-oscillator Chains.

Mutual synchronization of N serially connected spintronic nano-oscillators boosts their coherence by N and peak power by N2. Increasing the number of synchronized nano-oscillators in chains holds significance for improved signal quality and emerging applications such as oscillator based unconventional computing. We successfully fabricate spin Hall nano-oscillator chains with up to 50 serially connected nanoconstrictions using W/NiFe, W/CoFeB/MgO, and NiFe/Pt stacks. Our experiments demonstrate robust and complete mutual synchronization of 21 nanoconstrictions at an operating frequency of 10 GHz, achieving line widths <134 kHz and quality factors >79,000. As the number of mutually synchronized oscillators increases, we observe a quadratic increase in peak power, resulting in 400-fold higher peak power in long chains compared to individual nanoconstrictions. While chains longer than 21 nanoconstrictions also achieve complete mutual synchronization, it is less robust, and their signal quality does not improve significantly, as they tend to break into partially synchronized states.

Magnetic-Proximity-Induced Efficient Charge-to-Spin Conversion in Large-Area PtSe2/Ni80Fe20 Heterostructures.

As a topological Dirac semimetal with controllable spin-orbit coupling and conductivity, PtSe2, a transition-metal dichalcogenide, is a promising material for several applications, from optoelectrics to sensors. However, its potential for spintronics applications has yet to be explored. In this work, we demonstrate that the PtSe2/Ni80Fe20 heterostructure can generate large damping-like current-induced spin-orbit torques (SOT), despite the absence of spin-splitting in bulk PtSe2. The efficiency of charge-to-spin conversion is found to be -0.1 ± 0.02 nm-1 in PtSe2/Ni80Fe20, which is 3 times that of the control sample, Ni80Fe20/Pt. Our band structure calculations show that the SOT due to PtSe2 arises from an unexpectedly large spin splitting in the interfacial region of PtSe2 introduced by the proximity magnetic field of the Ni80Fe20 layer. Our results open up the possibilities of using large-area PtSe2 for energy-efficient nanoscale devices by utilizing proximity-induced SOT.

Implementation of Nanopore sequencing as a pragmatic workflow for copy number variant confirmation in the clinic.

BACKGROUND: Diagnosis of rare genetic diseases can be a long, expensive and complex process, involving an array of tests in the hope of obtaining an actionable result. Long-read sequencing platforms offer the opportunity to make definitive molecular diagnoses using a single assay capable of detecting variants, characterizing methylation patterns, resolving complex rearrangements, and assigning findings to long-range haplotypes. Here, we demonstrate the clinical utility of Nanopore long-read sequencing by validating a confirmatory test for copy number variants (CNVs) in neurodevelopmental disorders and illustrate the broader applications of this platform to assess genomic features with significant clinical implications. METHODS: We used adaptive sampling on the Oxford Nanopore platform to sequence 25 genomic DNA samples and 5 blood samples collected from patients with known or false-positive copy number changes originally detected using short-read sequencing. Across the 30 samples (a total of 50 with replicates), we assayed 35 known unique CNVs (a total of 55 with replicates) and one false-positive CNV, ranging in size from 40 kb to 155 Mb, and assessed the presence or absence of suspected CNVs using normalized read depth. RESULTS: Across 50 samples (including replicates) sequenced on individual MinION flow cells, we achieved an average on-target mean depth of 9.5X and an average on-target read length of 4805 bp. Using a custom read depth-based analysis, we successfully confirmed the presence of all 55 known CNVs (including replicates) and the absence of one false-positive CNV. Using the same CNV-targeted data, we compared genotypes of single nucleotide variant loci to verify that no sample mix-ups occurred between assays. For one case, we also used methylation detection and phasing to investigate the parental origin of a 15q11.2-q13 duplication with implications for clinical prognosis. CONCLUSIONS: We present an assay that efficiently targets genomic regions to confirm clinically relevant CNVs with a concordance rate of 100%. Furthermore, we demonstrate how integration of genotype, methylation, and phasing data from the Nanopore sequencing platform can potentially simplify and shorten the diagnostic odyssey.

A phase II study of gemcitabine and docetaxel combination in relapsed metastatic or unresectable locally advanced synovial sarcoma.

Synovial sarcoma (SS) is one of the commonest non-rhabdomyosarcoma soft tissue sarcoma with limited treatment options in the relapsed and advanced settings. The combination of gemcitabine and docetaxel has demonstrated its role predominantly in leiomyosarcoma and pleomorphic sarcomas but has not been prospectively studied in SS. This trial assesses the efficacy, tolerability and quality of life (QoL) with this regimen in metastatic/unresectable locally advanced relapsed SS.Patients and methods This was a single-arm, two-stage, phase II, investigator-initiated interventional study among patients with metastatic or unresectable locally advanced SS who had progressed after at least one line of chemotherapy. Gemcitabine 900 mg/m2 on days 1 and 8 and docetaxel 75 mg/m2 on day 8 were administered intravenously every 21 days. The primary endpoint was 3-month progression-free rate (PFR); overall survival (OS), progression-free survival (PFS), overall response rate (ORR), safety and quality of life (QoL) constituted the secondary endpoints.Results Twenty-two patients were enrolled between March 2020 and September 2021 and the study had to be closed early due to slow accrual. The study population comprised of 18 (81.8%) patients with metastatic disease and 4 (18.2%) patients with locally advanced, unresectable disease. The most common primary sites of disease were extremity in 15 (68%) and the median number of lines of prior therapies received was 1 (range 1-4). 3-month PFR was 45.4% (95% CI 24.8-66.1) and ORR was 4.5%. Median progression-free survival (PFS) was 3 months (95% CI 2.3-3.6) and median OS was 14 months (95% CI 8.9-19.0). 7 (31.8%) patients experienced grade 3 or worse toxicities, including anemia (18%), neutropenia (9%) and mucositis (9%). QoL analysis demonstrated significant decline in certain functional and symptom scales, while financial and global health scales remained stable.Conclusion This is the first prospective study on the combination of gemcitabine and docetaxel performed specifically in patients with advanced, relapsed SS. Although the accrual of patients could not be completed as planned, the therapy did produce clinically meaningful outcomes and met its primary endpoint of 3-month PFR. This result, along with the manageable toxicity profile and stable global health status on QoL analysis, should encourage further studies.Trial registration This trial was prospectively registered under the Clinical Trials Registry of India on 26/02/2020 (Registration number: CTRI/2020/02/023612).

Determinants and impact of diagnostic interval in bone sarcomas: A retrospective cohort study.

BACKGROUND: Diagnostic delays in cancers are frequent in developing countries due to poor health infrastructure. Existing literature from developed countries suggests that diagnostic interval in bone sarcomas is primarily dictated by tumour biology with no impact on survival. This study evaluates the social and biological determinants of the diagnostic interval in bone sarcomas in a resource-challenged setting and assesses its impact on treatment outcomes. METHODS: A retrospective single-institutional study was conducted on patients with high-grade bone sarcomas recorded in the sarcoma clinic database between 2003 and 2018. Baseline clinical characteristics and treatment outcomes were recorded. Logistic regression was performed to assess the impact of baseline clinical and social characteristics (distance from treating centre and rural vs. urban residence) on the diagnostic interval. Further, the impact of diagnostic interval on histologic response to neoadjuvant chemotherapy, amputation requirement in extremity sarcomas and survival was evaluated. RESULTS: A total of 1227 patients were included for analysis. The median diagnostic interval was 4 months (3-7 months). Age above 18 years, Ewing sarcoma (ES) diagnosis, absence of fever at presentation and tumour size above 7.5 cm were predictors of a longer diagnostic interval (>4 months). The length of the diagnostic interval did not impact amputation requirement or survival outcomes. However, the proportion of patients with good necrosis post-neoadjuvant chemotherapy was lower among patients with longer diagnostic intervals (25% vs. 34·16%; p-value = .04). CONCLUSION: Tumour characteristics rather than social factors determined the diagnostic interval. Diagnostic interval did not impact survival outcomes even in a resource-constrained setting.

Methotrexate, an anti-inflammatory drug, inhibits Hepatitis E viral replication.

Hepatitis E Virus (HEV) is a positively oriented RNA virus having a 7.2 kb genome. HEV consists of three open reading frames (ORF1-3). Of these, ORF1 codes for the enzymes Methyltransferase (Mtase), Papain-like cysteine protease (PCP), RNA helicase, and RNA-dependent RNA polymerase (RdRp). Unavailability of a vaccine or effective drug against HEV and considering the side effects associated with the off-label use of ribavirin (RBV) and pegylated interferons, an alternative approach is required by the modulation of specific enzymes to prevent the infection. HEV helicase is involved in unwinding the double-stranded RNA, RNA processing, transcriptional regulation, and pre-mRNA processing. Therefore, we screened FDA-approved compounds from the ZINC15 database against the modelled 3D structure of HEV helicase and found that methotrexate and compound A (Pubchem ID BTB07890) inhibit the NTPase and dsRNA unwinding activity leading to inhibition of HEV RNA replication. This may be further authenticated by in vivo study.

Investigation of enhanced H2 production from municipal solid waste gasification via artificial neural network with data on tar compounds.

An artificial neural network (ANN) is a biologically inspired computational technique that imitates the behavior and learning process of the human brain. In this study, ANN technique was applied to assess the gasification of municipal solid waste (MSW) with the aim of enhancing the H2 production. The experiments were conducted using a horizontal tube reactor under different parameters: temperatures, MSW loadings, residence times, and equivalence ratios. The input and output variables (released gases) were tested and trained using back-propagation algorithm, and the data distribution by K-fold contrivance. The values of the training (80% data) and validation (20% data) dataset were found satisfactory. The values of regression coefficient (R2) for the training phase were lied between 0.9392 and 0.9991, and 0.9363 and 0.993824 for the testing phase. Whereas; the values of root mean square error (RSME) for the training phase were lied between 0.4111 and 0.8422, and between 0.1476 and 0.7320 for the testing phase. Higher H2 production of 42.1 vol% was produced at the higher reaction temperature of 900 °C with LHV of 11.2 MJ/Nm3. According to the tar analysis, the dominant compounds were aromatics (17 compounds) followed by polycyclic aromatic, phenyl, aliphatic, aromatic heterocyclic, polycyclic, and aromatic ketone compounds.

Profile of Pathogenic Mutations and Evaluation of Germline Genetic Testing Criteria in Consecutive Breast Cancer Patients Treated at a North Indian Tertiary Care Center.

BACKGROUND: The burden of hereditary breast cancer in India is not well defined. Moreover, genetic testing criteria (National Comprehensive Cancer Network [NCCN] and Mainstreaming Cancer Genetics [MCG] Plus) have never been validated in the Indian population. METHODS: All new female breast cancer patients from 1st March 2019 to 28th February 2020 were screened. Those providing informed consent and without previous genetic testing were recruited. Multigene panel testing (107 genes) by next-generation sequencing was performed for all patients. The frequency of pathogenic/likely pathogenic (P/LP) mutations between patients qualifying and not qualifying the testing criteria was compared and their sensitivity was computed. RESULTS: Overall, 275 breast cancer patients were screened and 236 patients were included (median age 45 years); 30 patients did not consent and 9 patients previously underwent genetic testing. Thirty-four (14%) women had a positive family history and 35% had triple-negative breast cancer. P/LP mutations were found in 44/236 (18.64%) women; mutations in BRCA1 (22/47, 46.8%) and BRCA2 (9/47, 19.1%) were the most common, with 34% of mutations present in non-BRCA genes. Patients qualifying the testing criteria had a higher risk of having a P/LP mutation (NCCN: 23.6% vs. 7.04%, p = 0.03; MCG plus: 24.8% vs. 7.2%, p = 0.01). The sensitivity of the NCCN criteria was 88.6% (75.4-96.2) and 86.36% (72.65-94.83) for MCG plus. More than 95% sensitivity was achieved if all women up to 60 years of age were tested. Cascade testing was performed in 31 previous (16/44 families), with 23 testing positive. CONCLUSIONS: The frequency of P/LP mutations in India is high, with significant contribution of non-BRCA genes. Testing criteria need modification to expand access to testing.

Characteristics & outcomes of cancer patients with COVID-19: A multicentre retrospective study from India.

Background & objectives: High mortality has been observed in the cancer population affected with COVID-19 during this pandemic. We undertook this study to determine the characteristics and outcomes of cancer patients with COVID-19 and assessed the factors predicting outcome. Methods: Patients of all age groups with a proven history of malignancy and a recent diagnosis of SARS-CoV-2 infection based on nasal/nasopharyngeal reverse transcriptase (RT)-PCR tests were included. Demographic, clinical and laboratory variables were compared between survivors and non-survivors groups, with respect to observed mortality. Results: Between May 11 and August 10, 2020, 134 patients were included from the three centres and observed mortality was 17.1 per cent. The median age was 53 yr (interquartile range 39-61 yr) and thirty four patients (25%) were asymptomatic. Solid tumours accounted for 69.1 per cent and breast cancer was the most common tumour type (20%). One hundred and five patients (70.5%) had received chemotherapy within the past four weeks and 25 patients (19.3%) had neutropenia at presentation. On multivariate analysis, age [odds ratio (OR) 7.99 (95% confidence interval [CI] 1.18-54.00); P=0.033], haemoglobin [OR 6.28 (95% CI 1.07-37.04); P=0.042] neutrophil-lymphocyte ratio [OR 12.02 (95% CI 2.08-69.51); P=0.005] and baseline serum albumin [OR 18.52 (95% CI 2.80-122.27); P=0.002], were associated with higher mortality. Recent chemotherapy, haematological tumours type and baseline neutropenia did not affect the outcome. Interpretation & conclusions: Higher mortality in moderate and severe infections was associated with baseline organ dysfunction and elderly age. Significant proportion of patients were asymptomatic and might remain undetected.

An evaluation of inter and intra population structure of Uttar Pradesh, inferred from 24 autosomal STRs.

AIM: The present study was designed to explore the STR diversity and genomic history of the inhabitants of the most populous subdivision of the country. A set of 24 hypervariable autosomal STRs was used to estimate the genetic diversity within the studied population. A panel of 15 autosomal STRs, which is most common in the previously reported data sets, was used to estimate the genetic diversity between the studied population, and obtained unique relations were reported here. METHOD: The genetic diversity and polymorphism among 636 individuals of different ethnic groups, residing in Bareilly, Pilibhit, Shahjahanpur, Gorakhpur, Jhansi, and Varanasi regions of Uttar Pradesh, India, was investigated. This investigation was carried out via 24 autosomal STRs. RESULT: The 24 loci studied showed the highest value of combined power of discrimination (CPD = 1), combined power of exclusion (CPE = 0.99999999985), combined paternity index (CPI = 6.10 × 109) and lowest combined matching probability (CPM = 7.90 × 10-31). CONCLUSION: The studied population showed genetic closeness with the population of Uttarakhand, the Jats of Delhi,the Jat Sikh (Punjab), and the population of Rajasthan. Among the tested loci, SE33 and Penta E were found to be most useful in terms of the highest discrimination power, lowest matching probability, the highest power of exclusion, and highest polymorphism information content for the Uttar Pradesh population .

Forensic characterization and genomic diversity of Assam population viewed from 23 autosomal STRs.

In order to find out the genetic structure and characterize the forensic features of 23 autosomal STRs in the population of Assam, PowerPlex® Fusion 6C amplification kit was employed to genotype 292 unrelated individuals from Assam, India. A total of 79 different alleles were observed across 23 autosomal STRs with the corresponding frequency of alleles, which ranges from 0.002 to 0.406. Selected 23 loci were observed useful together with the highest value of combined discrimination power (CPD = 1), combined exclusion power (CPE = 0.999999999914), combined paternity index (CPI = 3.04 × 109), and all studied loci combined showing the lowest matching probability which is (CPM = 1.29 × 10-29). Additionally, in comparison with neighboring population, Assam population showed genetic closeness with Indian population. The genetic data of the present study will enrich the existing Indian autosomal DNA database and be useful for forensic and genealogical applications.

Association Between Indefinite Dysplasia and Advanced Neoplasia in Patients With Inflammatory Bowel Diseases Undergoing Surveillance.

BACKGROUND & AIMS: Little is known about the clinical significance of indefinite dysplasia (IND) in patients with inflammatory bowel diseases (IBD) undergoing colonoscopic surveillance for colorectal neoplasia. METHODS: We conducted a retrospective cohort analysis of 492 patients with colonic IBD for 8 or more years or concomitant primary sclerosing cholangitis, with no history of advanced colorectal neoplasia (high-grade dysplasia or colorectal cancer) or colectomy, undergoing colorectal neoplasia surveillance at a tertiary IBD referral center from 2001 through 2017. Subjects received consistent histopathologic grading of dysplasia. We collected data on time to development of (advanced) colorectal neoplasia or colectomy using Kaplan Meier methods. We identified factors independently associated with (advanced) colorectal neoplasia with multivariable Cox regression analysis. RESULTS: After 2149 person-years of follow-up, 53 patients (10.8%) received a diagnosis of IND without prior or synchronous low-grade dysplasia (LGD). Compared to patients without dysplasia, patients with IND had a significantly higher risk of advanced colorectal neoplasia (adjusted hazard ratio, 6.85; 95% CI, 1.78-26.4) and colorectal neoplasia (adjusted hazard ratio, 3.25; 95% CI, 1.50-7.05), but not colectomy (P = .78). Compared to IND, LGD was associated with a significantly higher risk of advanced colorectal neoplasia (P = .05). Following a diagnosis of no dysplasia, IND only, or LGD, the incidence rates of advanced colorectal neoplasia were 0.4% per patient-year, 3.1% per patient-year, and 8.4% per patient-year, respectively. CONCLUSIONS: In a retrospective analysis of patients with IBD undergoing colorectal neoplasia surveillance with consistent histopathologic grading of dysplasia, IND was independently associated with a significant increase in risk of advanced colorectal neoplasia. These findings require validation and if confirmed, a reappraisal of the colorectal neoplasia surveillance guidelines.

No Association Between Pseudopolyps and Colorectal Neoplasia in Patients With Inflammatory Bowel Diseases.

BACKGROUND & AIMS: Patients with inflammatory bowel diseases who have postinflammatory polyps (PIPs) have an increased risk of colorectal neoplasia (CRN). European guidelines propose that patients with PIPs receive more frequent surveillance colonoscopies, despite limited evidence of this increased risk. We aimed to define the risk of CRN and colectomy in patients with inflammatory bowel diseases and PIPs. METHODS: We conducted a multicenter retrospective cohort study of patients with inflammatory bowel diseases who underwent colonoscopic surveillance for CRN, from January 1997 through January 2017, at 5 academic hospitals and 2 large nonacademic hospitals in New York or the Netherlands. Eligible patients had confirmed colonic disease with duration of at least 8 years (or any duration, if they also had primary sclerosing cholangitis) and no history of advanced CRN (high-grade dysplasia or colorectal cancer) or colectomy. The primary outcome was occurrence of advanced CRN according to PIP status; secondary outcomes were occurrence of CRN (inclusive of low-grade dysplasia) and colectomy. RESULTS: Of 1582 eligible patients, 462 (29.2%) had PIPs. PIPs were associated with more severe inflammation (adjusted odds ratio 1.32; 95% confidence interval [CI] 1.13-1.55), greater disease extent (adjusted odds ratio 1.92; 95% CI 1.34-2.74), and lower likelihood of primary sclerosing cholangitis (adjusted odds ratio 0.38; 95% CI 0.26-0.55). During a median follow-up period of 4.8 years, the time until development of advanced CRN did not differ significantly between patients with and those without PIPs. PIPs did not independently increase the risk of advanced CRN (adjusted hazard ratio 1.17; 95% CI 0.59-2.31). The colectomy rate was significantly higher in patients with PIPs (P = .01). CONCLUSIONS: In a retrospective analysis of data from 2 large independent surveillance cohorts, PIPs were associated with greater severity and extent of colon inflammation and higher rates of colectomy, but were not associated with development of any degree of CRN. Therefore, intervals for surveillance should not be shortened based solely on the presence of PIPs.

Shouji: a fast and efficient pre-alignment filter for sequence alignment.

MOTIVATION: The ability to generate massive amounts of sequencing data continues to overwhelm the processing capability of existing algorithms and compute infrastructures. In this work, we explore the use of hardware/software co-design and hardware acceleration to significantly reduce the execution time of short sequence alignment, a crucial step in analyzing sequenced genomes. We introduce Shouji, a highly parallel and accurate pre-alignment filter that remarkably reduces the need for computationally-costly dynamic programming algorithms. The first key idea of our proposed pre-alignment filter is to provide high filtering accuracy by correctly detecting all common subsequences shared between two given sequences. The second key idea is to design a hardware accelerator that adopts modern field-programmable gate array (FPGA) architectures to further boost the performance of our algorithm. RESULTS: Shouji significantly improves the accuracy of pre-alignment filtering by up to two orders of magnitude compared to the state-of-the-art pre-alignment filters, GateKeeper and SHD. Our FPGA-based accelerator is up to three orders of magnitude faster than the equivalent CPU implementation of Shouji. Using a single FPGA chip, we benchmark the benefits of integrating Shouji with five state-of-the-art sequence aligners, designed for different computing platforms. The addition of Shouji as a pre-alignment step reduces the execution time of the five state-of-the-art sequence aligners by up to 18.8×. Shouji can be adapted for any bioinformatics pipeline that performs sequence alignment for verification. Unlike most existing methods that aim to accelerate sequence alignment, Shouji does not sacrifice any of the aligner capabilities, as it does not modify or replace the alignment step. AVAILABILITY AND IMPLEMENTATION: https://github.com/CMU-SAFARI/Shouji. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Consecutive negative findings on colonoscopy during surveillance predict a low risk of advanced neoplasia in patients with inflammatory bowel disease with long-standing colitis: results of a 15-year multicentre, multinational cohort study.

OBJECTIVES: Surveillance colonoscopy is thought to prevent colorectal cancer (CRC) in patients with long-standing colonic IBD, but data regarding the frequency of surveillance and the findings thereof are lacking. Our aim was to determine whether consecutive negative surveillance colonoscopies adequately predict low neoplastic risk. DESIGN: A multicentre, multinational database of patients with long-standing IBD colitis without high-risk features and undergoing regular CRC surveillance was constructed. A 'negative' surveillance colonoscopy was predefined as a technically adequate procedure having no postinflammatory polyps, no strictures, no endoscopic disease activity and no evidence of neoplasia; a 'positive' colonoscopy was a technically adequate procedure that included at least one of these criteria. The primary endpoint was advanced colorectal neoplasia (aCRN), defined as high-grade dysplasia or CRC. RESULTS: Of 775 patients with long-standing IBD colitis, 44% (n=340) had >1 negative colonoscopy. Patients with consecutive negative surveillance colonoscopies were compared with those who had at least one positive colonoscopy. Both groups had similar demographics, disease-related characteristics, number of surveillance colonoscopies and time intervals between colonoscopies. No aCRN occurred in those with consecutive negative surveillance, compared with an incidence rate of 0.29 to 0.76/100 patient-years (P=0.02) in those having >1 positive colonoscopy on follow-up of 6.1 (P25-P75: 4.6-8.2) years after the index procedure. CONCLUSION: Within this large surveillance cohort of patients with colonic IBD and no additional high-risk features, having two consecutive negative colonoscopies predicted a very low risk of aCRN occurrence on follow-up. Our findings suggest that longer surveillance intervals in this selected population may be safe.

Absence of the glycosyltransferase WcaJ in Klebsiella pneumoniae ATCC13883 affects biofilm formation, increases polymyxin resistance and reduces murine macrophage activation.

Multidrug-resistant Klebsiella pneumoniae has emerged as one of the deadliest opportunistic nosocomial pathogens that forms biofilm for the establishment of chronic K. pneumoniae infections. Herein, we made an attempt to identify the genes involved in biofilm formation in the strain K. pneumoniae ATCC13883. To achieve this, we constructed mini-Tn5 transposon insertion mutants and screened them for biofilm production. We observed that the biofilm formation was enhanced in the mutant where the wcaJ gene was disrupted. WcaJ is the initiating enzyme of colanic acid synthesis and loads the first sugar (glucose-1-P) on the lipid carrier undecaprenyl phosphate. The absence of this glycosyltransferase results in the absence of colanic acid, which renders a non-mucoid phenotype to the mutant. Further, to determine the effect of mucoidy on antibiotic susceptibility, we tested the sensitivity of the strains towards different groups of antibiotics. Unlike the mucoid strains, the resistance of the non-mucoid cells was greater for polymyxins, but less for quinolones. Capsular polysaccharides are known to have a protective effect against phagocytosis, therefore we assessed the role of colanic acid in virulence by conducting infection studies on murine macrophages. Surprisingly, the ΔwcaJ strain was less efficient in macrophage activation and was not readily phagocytosed. Thus, the presence of colanic acid appeared to increase the immunogenicity of K. pneumoniae. Overall, the results indicate that the presence of colanic acid increases the vulnerability of K. pneumoniae towards both polymyxins and macrophages, implying that the mucoid strains are less threatening as compared to their high biofilm forming non-mucoid counterparts.