Multimodel habitats constructed by perfusion and/or diffusion MRI predict isocitrate dehydrogenase mutation status and prognosis in high-grade gliomas

AIM

To determine whether tumour vascular and cellular heterogeneity of high-grade glioma (HGG) is predictive of isocitrate dehydrogenase (IDH) mutation status and overall survival (OS) by using tumour habitat-based analysis constructed by perfusion and/or diffusion magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Seventy-eight HGG patients that met the 2021 World Health Organization WHO Classification of Tumors of the Central Nervous System, 5th edition (WHO CNS5), were enrolled to predict IDH mutation status, of which 32 grade 4 patients with unmethylated O6-methylguanine-DNA methyltransferase (MGMT) promoter were enrolled for prognostic analysis. The deep-learning-based model nnU-Net and K-means clustering algorithm were applied to construct the Traditional Habitat, Vascular Habitat (VH), Cellular Density Habitat (DH), and their Combined Habitat (CH). Quantitative parameters were extracted and compared between IDH-mutant and IDH-wild-type patients, respectively, and the prediction potential was evaluated by receiver operating characteristic (ROC) curve analysis. OS was analysed using Kaplan-Meier survival analysis and the log-rank test.

RESULTS

Compared with IDH-mutants, median relative cerebral blood volume (rCBVmedian) values in the whole enhancing tumour (WET), VH1, VH3, CH1-4 habitats were significantly increased in IDH-wild-type HGGs (all p<0.05). Additionally, the accuracy of rCBVmedian values in CH1 outperformed other habitats in identifying IDH mutation status (p<0.001) at a cut-off value of 4.83 with AUC of 0.815. Kaplan-Meier survival analysis highlighted significant differences in OS between the populations dichotomised by the median of rCBVmedian in WET, VH1, CH1-3 habitats (all p<0.05).

CONCLUSIONS

The habitat imaging technique may improve the accuracy of predicting IDH mutation status and prognosis, and even provide a new direction for subsequent personalised precision treatment.

Emergence of an ST1326 (CG258) Multi-Drug Resistant Klebsiella pneumoniae Co-harboring mcr-8.2, ESBL Genes, and the Resistance-Nodulation-Division Efflux Pump Gene Cluster tmexCD1-toprJ1 in China

CG258 is the dominant carbapenemase-producing Klebsiella pneumoniae clone worldwide and treatment of infections caused by this clone relies largely on the last-line antibiotics, colistin, and tigecycline. However, the emergence and global dissemination of mcr and tmexCD1-toprJ1 genes have significantly compromised their clinical applications. CG258 K. pneumoniae carrying both mcr and tmexCD1-toprJ1 have not been reported. A colistin-resistant strain T698-1 belonging to ST1326, a member of CG258, was isolated from the intestinal sample of a patient and characterized by the antimicrobial susceptibility testing, conjugation assay, WGS and bioinformatics analysis. It was resistant to colistin, tetracycline, aminoglycoside, fluoroqinolone, phenicols, sulfonamide, and some β-lactams, and positive for mcr-8.2, tmexCD1-toprJ1, and ESBL genes (bla_DHA–1 and bla_CTX–M–15). The tmexCD1-toprJ1 gene cluster was located in an multi-drug resistant (MDR) region flanked by TnAs1 elements on an IncHI1B/FIB plasmid. The genetic context of tmexCD1-toprJ1 was slightly distinct from previously reported Tn5393-like structures, with an IS26 element disrupting the upstream Tn5393 and its adjacent genetic elements. The mcr-8.2 gene was inserted into the backbone of an IncFII/FIA plasmid with the genetic context of ISEcl1-mcr-8.2-orf-ISKpn26. To our knowledge, this is the first report of co-occurrence of mcr-8.2 and tmexCD1-toprJ1 in a CG258 K. pneumoniae strain. Though this strain is tigecycline sensitive, the acquisition of colistin and tigecycline resistance determinants by the endemic CG258 K. pneumoniae clone still poses a serious public health concern. CG258, which became resistant to multiple last resort antibiotics, would be the next emerging superbug.

Systematic analysis of copy-number variations associated with early pregnancy loss

OBJECTIVES

Embryonic numerical and structural chromosomal abnormalities are the most common cause of early pregnancy loss. However, the role of submicroscopic copy-number variations (CNVs) in early pregnancy loss is unclear, and little is known about the critical regions and candidate genes for miscarriage, because of the large size of structural chromosomal abnormalities. The aim of this study was to identify potential miscarriage-associated submicroscopic CNVs and critical regions of large CNVs as well as candidate genes for miscarriage.

METHODS

Over a 5-year period, 5180 fresh miscarriage specimens were investigated using quantitative fluorescent polymerase chain reaction/CNV sequencing or chromosomal microarray analysis. Statistically significant submicroscopic CNVs were identified by comparing the frequency of recurrent submicroscopic CNVs between cases and a published control cohort. Furthermore, genes within critical regions of miscarriage-associated CNVs were prioritized by integrating the Residual Variation Intolerance Score and the human gene expression dataset for identification of potential miscarriage candidate genes.

RESULTS

Results without significant maternal-cell contamination were obtained in 5003 of the 5180 (96.6%) cases. Clinically significant chromosomal abnormalities were identified in 59.1% (2955/5003) of these cases. Three recurrent submicroscopic CNVs (microdeletions in 22q11.21, 2q37.3 and 9p24.3p24.2) were significantly more frequent in miscarriage cases, and were considered to be associated with miscarriage. Moreover, 44 critical regions of large CNVs were observed, including 14 deletions and 30 duplications. There were 309 genes identified as potential miscarriage candidate genes through gene-prioritization analysis.

CONCLUSIONS

We identified potential miscarriage candidate CNVs and genes. These data demonstrate the importance of CNVs in the etiology of miscarriage and highlight the importance of ongoing analysis of CNVs in the study of miscarriage. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Thermal properties of a series of tetrafunctional fluorene-based oxazines/P-a blends

A new series of aniline and aniline-mixed tetrafunctional fluorene-based oxazine monomers were synthesized using 2,7-hydroxy-9,9-bis-(4-hydroxyphenyl) fluorene, paraformaldehyde, and primary amines (including aniline or aniline mixed with n-butylamine or n-octylamine composition). Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy were used to characterize the structure of the monomers. The copolymers were obtained by adding the monomers into a typical monofunctional polybenzoxazine (phenol-aniline-based benzoxazine). Differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis were performed to study the thermal properties of the copolymers. The copolymers exhibited high glass transition temperature values (164–201°C). A good thermal stability was also obtained with a 5% weight loss temperature over 355°C and high char yields at 800°C (42–50%).

Modeling the synergy between HSV-2 and HIV and potential impact of HSV-2 therapy

Mounting evidence indicates that genital HSV-2 infection may increase susceptibility to HIV infection and that co-infection may increase infectiousness. Accordingly, antiviral treatment of people with HSV-2 may mitigate the incidence of HIV in populations where both pathogens occur. To better understand the epidemiological synergy between HIV and HSV-2, we formulate a deterministic compartmental model that describes the transmission dynamics of these pathogens. Unlike earlier models, ours incorporates gender and heterogeneous mixing between activity groups. We derive explicit expressions for the reproduction numbers of HSV-2 and HIV, as well as the invasion reproduction numbers via next generation matrices. A qualitative analysis of the system includes the local and global behavior of the model. Simulations reinforce these analytical results and demonstrate epidemiological synergy between HSV-2 and HIV. In particular, numerical results show that HSV-2 favors the invasion of HIV, may dramatically increase the peak as well as reducing the time-to-peak of HIV prevalence, and almost certainly has exacerbated HIV epidemics. The potential population-level impact of HSV-2 on HIV is demonstrated by calculating the fraction of HIV infections attributable to HSV-2 and the difference between HIV prevalence in the presence and absence of HSV-2. The potential impact of treating people with HSV-2 on HIV control is demonstrated by comparing HIV prevalence with and without HSV-2 therapy. Most importantly, we illustrate that the aforementioned aspects of the population dynamics can be significantly influenced by the sexual structure of the population.

Assessing the effect of non-pharmaceutical interventions on containing an emerging disease

Non-pharmaceutical interventions, such as quarantine, isolation and entry screening, are usually the primary public health measures to control the spread of an emerging infectious disease through a human population. This paper proposes a multi-regional deterministic compartmental model to assess the effectiveness and implications of non-pharmaceutical interventions. The reproduction number is determined as the spectral radius of a nonnegative matrix product. Comparisons are made using the reproduction number, epidemic peaks and cumulative number of infections and mortality as indexes. Simulation results show that quarantine of suspected cases and isolation of cases with symptom are effective in reducing disease burden for multiple regions. Using entry screening strategy leads to a moderate time delay for epidemic peaks, but is of no help for preventing an epidemic breaking out. The study further shows that isolation strategy is always the best choice in the presence or absence of stringent hygiene precautions and should be given priority in combating an emerging epidemic.