The potential impact of post-COVID symptoms in the healthcare sector.

BACKGROUND: The phenomenon of post-COVID syndrome (PCS) is evolving from an abstract array of non-specific symptoms to an identifiable clinical entity of variable severity. Its frequency and persistence have implications for service delivery and workforce planning. AIMS: This study was aimed to assess the prevalence of symptoms consistent with PCS and the subjective degree of recovery in a cohort of healthcare workers, focusing on those who have returned to work. METHODS: A study population of 1176 was surveyed when attending for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody testing. Two sub-groups were identified: those with known (i.e. diagnosed on PCR testing) and assumed (i.e. antibody evidence of previous infection) SARs-CoV-2 infection, at least 12 weeks prior to the study. Each group was asked about their subjective degree of recovery and the nature of their persistent symptoms. Results were analysed via excel and SPSS. RESULTS: In total, 144 employees showed PCR evidence of previous infection, with 139 of these being infected at least 12 weeks prior to the study. Of these 139, only 19% (n = 26) reported feeling 100% recovered, and 71% reported persistent symptoms. Of those with assumed SARS-CoV-2 infection (n = 78), 32 (41%) were truly asymptomatic since the commencement of the pandemic, while 46 (59%) described symptoms suggestive of possible infection at least 12 weeks prior to the study. Of this latter group, 23% (n = 18) also reported residual symptoms. CONCLUSIONS: PCS is prevalent among this group, including those not previously diagnosed with COVID-19. Its' frequency and duration present challenges to employers with regards to the management of work availability and performance.

Prognostic gene expression signature for high-grade serous ovarian cancer.

BACKGROUND: Median overall survival (OS) for women with high-grade serous ovarian cancer (HGSOC) is ∼4 years, yet survival varies widely between patients. There are no well-established, gene expression signatures associated with prognosis. The aim of this study was to develop a robust prognostic signature for OS in patients with HGSOC. PATIENTS AND METHODS: Expression of 513 genes, selected from a meta-analysis of 1455 tumours and other candidates, was measured using NanoString technology from formalin-fixed paraffin-embedded tumour tissue collected from 3769 women with HGSOC from multiple studies. Elastic net regularization for survival analysis was applied to develop a prognostic model for 5-year OS, trained on 2702 tumours from 15 studies and evaluated on an independent set of 1067 tumours from six studies. RESULTS: Expression levels of 276 genes were associated with OS (false discovery rate < 0.05) in covariate-adjusted single-gene analyses. The top five genes were TAP1, ZFHX4, CXCL9, FBN1 and PTGER3 (P < 0.001). The best performing prognostic signature included 101 genes enriched in pathways with treatment implications. Each gain of one standard deviation in the gene expression score conferred a greater than twofold increase in risk of death [hazard ratio (HR) 2.35, 95% confidence interval (CI) 2.02-2.71; P < 0.001]. Median survival [HR (95% CI)] by gene expression score quintile was 9.5 (8.3 to -), 5.4 (4.6-7.0), 3.8 (3.3-4.6), 3.2 (2.9-3.7) and 2.3 (2.1-2.6) years. CONCLUSION: The OTTA-SPOT (Ovarian Tumor Tissue Analysis consortium - Stratified Prognosis of Ovarian Tumours) gene expression signature may improve risk stratification in clinical trials by identifying patients who are least likely to achieve 5-year survival. The identified novel genes associated with the outcome may also yield opportunities for the development of targeted therapeutic approaches.

Correction: Safety and utility of image-guided research biopsies in relapsed high-grade serous ovarian carcinoma-experience of the BriTROC consortium.

This article was originally published under a CC BY NC SA License, but has now been made available under a CC BY 4.0 License.

Safety and utility of image-guided research biopsies in relapsed high-grade serous ovarian carcinoma-experience of the BriTROC consortium.

BACKGROUND: Investigating tumour evolution and acquired chemotherapy resistance requires analysis of sequential tumour material. We describe the feasibility of obtaining research biopsies in women with relapsed ovarian high-grade serous carcinoma (HGSC). METHODS: Women with relapsed ovarian HGSC underwent either image-guided biopsy or intra-operative biopsy during secondary debulking, and samples were fixed in methanol-based fixative. Tagged-amplicon sequencing was performed on biopsy DNA. RESULTS: We screened 519 patients in order to enrol 220. Two hundred and two patients underwent successful biopsy, 118 of which were image-guided. There were 22 study-related adverse events (AE) in the image-guided biopsies, all grades 1 and 2; pain was the commonest AE. There were pre-specified significant AE in 3/118 biopsies (2.5%). 87% biopsies were fit-for-purpose for genomic analyses. Median DNA yield was 2.87 µg, and was higher in biopsies utilising 14 G or 16 G needles compared to 18 G. TP53 mutations were identified in 94.4% patients. CONCLUSIONS: Obtaining tumour biopsies for research in relapsed HGSC is safe and feasible. Adverse events are rare. The large majority of biopsies yield sufficient DNA for genomic analyses-we recommend use of larger gauge needles and methanol fixation for such biopsies, as DNA yields are higher but with no increase in AEs.

A viscoactive constitutive modeling framework with variational updates for the myocardium.

We present a constitutive modeling framework for contractile cardiac mechanics by formulating a single variational principle from which incremental stress-strain relations and kinetic rate equations for active contraction and relaxation can all be derived. The variational framework seamlessly incorporates the hyperelastic behavior of the relaxed and contracted tissue along with the rate - and length - dependent generation of contractile force. We describe a three-element, Hill-type model that unifies the active tension and active deformation approaches. As in the latter approach, we multiplicatively decompose the total deformation gradient into active and elastic parts, with the active deformation parametrizing the contractile Hill element. We adopt as internal variables the fiber, cross-fiber, and sheet normal stretch ratios. The kinetics of these internal variables are modeled via definition of a kinetic potential function derived from experimental force-velocity relations. Additionally, we account for dissipation during tissue deformation by adding a Newtonian viscous potential. To model the force activation, the kinetic equations are coupled with the calcium transient obtained from a cardiomyocyte electrophysiology model. We first analyze our model at the material point level using stress and strain versus time curves for different viscosity values. Subsequently, we couple our constitutive framework with the finite element method (FEM) and study the deformation of three-dimensional tissue slabs with varying cardiac myocyte orientation. Finally, we simulate the contraction and relaxation of an ellipsoidal left ventricular model and record common kinematic measures, such as ejection fraction, and myocardial tissue volume changes.

Methanol-based fixation is superior to buffered formalin for next-generation sequencing of DNA from clinical cancer samples.

BACKGROUND: Next-generation sequencing (NGS) of tumour samples is a critical component of personalised cancer treatment, but it requires high-quality DNA samples. Routine neutral-buffered formalin (NBF) fixation has detrimental effects on nucleic acids, causing low yields, as well as fragmentation and DNA base changes, leading to significant artefacts. PATIENTS AND METHODS: We have carried out a detailed comparison of DNA quality from matched samples isolated from high-grade serous ovarian cancers from 16 patients fixed in methanol and NBF. These experiments use tumour fragments and mock biopsies to simulate routine practice, ensuring that results are applicable to standard clinical biopsies. RESULTS: Using matched snap-frozen tissue as gold standard comparator, we show that methanol-based fixation has significant benefits over NBF, with greater DNA yield, longer fragment size and more accurate copy-number calling using shallow whole-genome sequencing (WGS). These data also provide a new approach to understand and quantify artefactual effects of fixation using non-negative matrix factorisation to analyse mutational spectra from targeted and WGS data. CONCLUSION: We strongly recommend the adoption of methanol fixation for sample collection strategies in new clinical trials. This approach is immediately available, is logistically simple and can offer cheaper and more reliable mutation calling than traditional NBF fixation.

Evidence for separatrix formation and sustainment with steady inductive helicity injection.

The first sustainment of toroidal plasma current of 50 kA at up to 3 times the injected currents, added in quadrature, using steady inductive helicity injection is described. Separatrix currents-currents not linking the helicity injectors-are sustained up to 40 kA. Decreases in the n=1 toroidal mode of the poloidal magnetic field at higher current amplifications indicate more quiescent, direct toroidal current drive. Results are achieved in HIT-SI (with a spheromak of major radius 0.3 m) during deuterium operations immediately after helium operation. These results represent a breakthrough in the development of this new current drive method for magnetic confinement fusion.

Associations between leptin and adiponectin receptor upregulation, visceral obesity and tumour stage in oesophageal and junctional adenocarcinoma.

BACKGROUND: Obesity is associated with oesophageal adenocarcinoma, but mechanisms linking fat and carcinogenesis remain poorly understood. Altered circulating adipocytokines may be important. This study aimed to identify pathways through which visceral fat impacts on tumour biology. METHODS: Seventy-five patients with oesophageal adenocarcinoma underwent anthropometric and radiological assessment of obesity. Expression of leptin receptor (ObR) and adiponectin receptors 1 and 2 (AdipR1, AdipR2) was quantified by real-time reverse transcriptase-polymerase chain reaction. The human oesophageal adenocarcinoma cell line OE33 was used as the calibrator sample. RESULTS: Ninety-one per cent of tumours expressed ObR, 95 per cent expressed AdipR1 and 100 per cent expressed AdipR2. Relative expression of ObR was upregulated in 67 per cent, and AdipR1 and AdipR2 were downregulated in 55 and 68 per cent respectively, relative to the calibrator sample. Upregulated ObR and AdipR2 expression was significantly associated with anthropometric and radiological measures of obesity. Upregulated ObR was associated with advanced tumour and node category (P = 0.036 and P = 0.025 respectively), and upregulated AdipR2 with nodal involvement (P = 0.037). CONCLUSION: Obesity is associated with upregulated ObR and AdipR2 expression in oesophageal adenocarcinoma. The association of ObR and AdipR2 with tumour stage suggest that pathways involving adipocytokines affect tumour biology.

Simulated roots and host feeding enhance infection of subterranean insects by the entomopathogenic nematode Steinernema carpocapsae.

Steinernema carpocapsae can be effective against root-feeding insects despite its reputation as a sedentary ambusher. In pot experiments, using twigs as surrogate roots and pine weevil larvae as targets, we tested the hypothesis that roots serve as physical routeways and conduits of feeding-associated stimuli, thus enhancing the success of S. carpocapsae applied at the surface against subterranean hosts. Insect mortality was lowest (25%) in the absence of plant material, increased to 48% when twigs linked nematodes and insects, and further increased to 69% when the insects were allowed feed on the twigs. This is the first experimental support for the root-routeway hypothesis.

The lethal and sub-lethal consequences of entomopathogenic nematode infestation and exposure for adult pine weevils, Hylobius abietis (Coleoptera: Curculionidae).

Entomopathogenic nematodes (EPN) frequently kill their host within 1-2 days, and interest in EPN focuses mainly on their lethality. However, insects may take longer to die, or may fail to die despite being infected, but little is known about the effects of EPN infection on insects, other than death. Here we investigate both lethal and sub-lethal effects of infection by two EPN species, Steinernema carpocapsae and Heterorhabditis downesi, on adults of the large pine weevil, Hylobius abietis. Following 12h nematode-weevil contact in peat, S. carpocapsae killed a significantly higher proportion of weevils (87-93%) than H. downesi (43-57%) at all concentrations tested. Less than 10% of weevils were dead within 2 days, and weevils continued to die for up to 10 days after exposure (LT(50) of 3 days or more). In a separate experiment, live weevils dissected 6 days after a 24h exposure to nematodes on filter paper harbored encapsulated and dead nematodes, showing that weevils could defend themselves against infection. Some live weevils also harbored live nematodes 6 days after they had been removed from the nematode infested medium. Feeding by weevils was not affected by infection with, or exposure to, either species of EPN. We discuss these results in relation to the use of EPN in biological control against H. abietis.

Building a bioresource for esophageal research: lessons from the early experience of an academic medical center.

The establishment of biorepositories, linked to clinical and epidemiologic data, are central to the goals of personalized medicine and individualized cancer therapy. Repositories of DNA, RNA, and serum samples are valuable resources for cancer research, enabling the investigation of the underlying causes of cancer development, progression, and prognosis, as well as providing a resource for the investigation of biomarkers for early detection and prediction of response. With a greater reliance on sample-derived data for molecular-based research and clinical care, improved standards and informatics for sample procurement, storage, and analysis are necessary to maximize the value of tissue collection for research participants, investigators, and academic medical centers. We present herein the experience of an academic medical center in establishing a repository for esophageal research, with discussion of elements to be considered when establishing such a resource, from the quality assurance of samples to the organized collection and storage of associated clinical data. The development of this biorepository required significant planning to identify and consent participants by dedicated clinical and research personnel. Ensuring the quality of any biobank is of utmost importance, and one must understand the sample variability that exists during the acquisition of biospecimens. The time and type of fixative have been optimized in our unit by standard operating protocols. Methods for biomolecule extraction were tested by examining both the quality and the quantity of recovered sample. These procedures were overseen by a designated biobank manager, responsible for the acquisition of the sample from surgery, which limits variability in sample collection. Our unit also has a dedicated database manager for the maintenance of quality clinical data linked to the bioresource. The development and expansion of such repositories, at local and national levels, is required to enable leading academic medical centers and their investigators to provide optimal and molecularly guided care to their patients.

Effect of intra-myocardial Algisyl-LVR™ injectates on fibre structure in porcine heart failure.

Recent preclinical trials have shown that alginate injections are a promising treatment for ischemic heart disease. Although improvements in heart function and global structure have been reported following alginate implants, the underlying structure is poorly understood. Using high resolution ex vivo MRI and DT-MRI of the hearts of normal control swine (n = 8), swine with induced heart failure (n = 5), and swine with heart failure and alginate injection treatment (n = 6), we visualized and quantified the fibre distribution and implant material geometry. Our findings show that the alginate injectates form solid ellipsoids with a retention rate of 68.7% ±â€¯21.3% (mean ±â€¯SD) and a sphericity index of 0.37 ±â€¯0.03. These ellipsoidal shapes solidified predominantly at the mid-wall position with an inclination of -4.9°â€¯±â€¯31.4° relative to the local circumferential direction. Overall, the change to left ventricular wall thickness and myofiber orientation was minor and was associated with heart failure and not the presence of injectates. These results show that alginate injectates conform to the pre-existing tissue structure, likely expanding along directions of least resistance as mass is added to the injection sites. The alginate displaces the myocardial tissue predominantly in the longitudinal direction, causing minimal disruption to the surrounding myofiber orientations.

High throughput spectrometer for fast localized Doppler measurements.

A new custom-built duo spectrometer has been commissioned for fast localized Doppler measurements of plasma ions in the Madison Symmetric Torus. The instrument combines very high optical throughput (transmission efficiency of 6% and etendue of 0.80 mm(2) sr divided into two simultaneous measurements) with good resolution (lambda/Deltalambda=5600). The design is a double grating variant of the Czerny-Turner layout and has been carefully optimized for fast (100 kHz) measurements of the C VI line at 343.4 nm. The instrument is currently being applied for high speed charge exchange recombination spectroscopy measurements.

Genetic functions promoting homologous recombination in Escherichia coli: a study of inversions in phage lambda.

We have studied homologous recombination in a derivative of phage lambda containing two 1.4-kb repeats in inverted orientation. Inversion of the intervening 2.5-kb segment occurred efficiently by the Escherichia coli RecBC pathway but markedly less efficiently by the lambda Red pathway or the E. coli RecE or RecF pathways. Inversion by the RecBCD pathway was stimulated by Chi sites located to the right of the invertible segment; this stimulation decreased exponentially by a factor of about 2 for each 2.2 kb between the invertible segment and the Chi site. In addition to RecA protein and RecBCD enzyme, inversion by the RecBC pathway required single-stranded DNA binding protein, DNA gyrase, DNA polymerase I and DNA ligase. Inversion appeared to occur either intra- or intermolecularly. These results are discussed in the framework of a current molecular model for the RecBC pathway of homologous recombination.

Regional segmentation of ventricular models to achieve repolarization dispersion in cardiac electrophysiology modeling.

The electrocardiogram (ECG) is one of the most significant outputs of a computational model of cardiac electrophysiology because it relates the numerical results to clinical data and is a universal tool for diagnosing heart diseases. One key features of the ECG is the T-wave, which is caused by longitudinal and transmural heterogeneity of the action potential duration (APD). Thus, in order to model a correct wave of repolarization, different cell properties resulting in different APDs must be assigned across the ventricular wall and longitudinally from apex to base. To achieve this requirement, a regional parametrization of the heart is necessary. We propose a robust approach to obtain the transmural and longitudinal segmentation in a general heart geometry without relying on ad hoc procedures. Our approach is based on auxiliary harmonic lifting analyses, already used in the literature to generate myocardial fiber orientations. Specifically, the solution of a sequence of Laplace boundary value problems allows parametrically controlled segmentation of both heart ventricles. The flexibility and simplicity of the proposed method is demonstrated through several representative examples, varying the locations and extents of the epicardial, midwall, and endocardial layers. Effects of the control parameters on the T-wave morphology are illustrated via computed ECGs.

Analysis of mutagenesis induced by expression of retroviral reverse transcriptase in Escherichia coli.

We showed that expression of reverse transcriptase from HIV or MuLV resulted in exceptionally high levels of mutagenesis in E coli. We observed high rates of mutagenesis in plasmid genes when reverse transcriptase was expressed off that plasmid. Although very high rates were observed in cis, our experiments could not detect mutagenic events in markers in other replicons (ie in trans). These results suggest mutagenic events occur preferentially on the same replicon in which the reverse transcriptase is encoded.

Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening.

A deficiency of hepatic guanosine triphosphate cyclohydrolase I is reported in a 4-month-old infant in whom positive results on a Guthrie phenylketonuria test in the neonatal period were found. Because of the significantly elevated serum phenylalanine levels a diagnosis of classical phenylketonuria was made, and dietary therapy was started. Urinary pteridine screening for cofactor variants, however, revealed extremely low levels of both neopterin and biopterin. This suggested the possibility of guanosine triphosphate cyclohydrolase I deficiency and led to additional confirmatory assays. Repeat urine, serum, and CSF pteridine profiles, combined with tetrahydrobiopterin-loading studies and the assay of guanosine triphosphate cyclohydrolase I activity in a liver biopsy, confirmed the defect. It is significant to note that the diagnosis was made before the onset of major clinical symptoms. This case illustrates the need for routine cofactor variant screening of all infants in whom hyperphenylalaninemia is diagnosed in the neonatal period.

The newer cephalosporins. Aztreonam and imipenem.

Many of the antimicrobial agents described here exhibit great advances over older drugs in terms of antimicrobial spectrum, clinical utility, and, sometimes, safety. The newer cephalosporins are useful for treatment of many common outpatient and inpatient infections. Aztreonam provides excellent coverage against a broad range of aerobic gram-negative bacteria, without the toxicity associated with aminoglycosides. Imipenem exhibits activity against an impressive array of pathogens. These antimicrobials are expensive, however, and some offer no advantages over older agents. Finally, all--including imipenem--are faced with increasing resistance of bacteria.

Selective inhibition of RecA functions by the Hc1 nucleoid condensation protein from Chlamydia trachomatis.

During the normal biphasic life cycle of Chlamydia trachomatis, the histone-like protein Hc1 promotes the condensation of nucleoids in elementary bodies, it may also displace nucleoproteins, including repair functions from chromatin. Hc1 was found to effectively inhibit the recombination and repair of the weak binding RecA430 mutant protein from Escherichia coli, but had minimal effects on the parental RecA(+) protein. Expression of Hc1 was also found to inhibit the repair activities of the C. trachomatis RecA protein but not recombination. These results suggest that chlamydial RecA may have evolved mechanisms to minimize Hc1 competition for recombinational activities.

The recA gene of Chlamydia trachomatis: cloning, sequence, and characterization in Escherichia coli.

The recA gene of Chlamydia trachomatis was isolated by complementation of an Escherichia coli recA mutant. The cloned gene restored resistance to methyl methanesulfonate in E. coli recA mutants. The DNA sequence of the chlamydial gene was determined and the deduced protein sequence compared with other RecA proteins. In E. coli recA deletion mutants, the cloned gene conferred moderate recombinational activity as assayed by Hfr matings. The chlamydial recA gene was efficient in repairing alkylated DNA but less so in repairing of UV damage when compared with the E. coli homologue. As detected by an SOS gene fusion, a small but measurable amount of LexA co-cleavage was indicated.