Radiation exposure, organ and effective dose of CT-guided liver biopsy as a function of lesion depth and size.

Computed tomography (CT)-guided percutaneous biopsies play an important role in the diagnostic workup of liver lesions. Because radiation dose accumulates rapidly due to repeated image acquisition in a relatively small scan area, analysing radiation exposure is critical for improving radiation protection of CT-guided interventions. The aim of this study was to assess the radiation dose of CT-guided liver biopsies and the influence of lesion parameters, and to establish a local diagnostic reference level (DRL). In this observational retrospective cohort study, dose data of 60 CT-guided liver biopsies between September 2016 and July 2017 were analysed. Radiation exposure was reported for volume-weighted CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose-length product (DLP) and effective dose (ED). Radiation dose of CT-guided liver biopsy was (median (interquartile range)): CTDIvol9.91 mGy (8.33-11.45 mGy), SSDE 10.42 mGy (9.39-11.70 mGy), DLP 542 mGy cm (410-733 mGy cm), ED 8.52 mSv (7.17-13.25 mSv). Radiation exposure was significantly higher in biopsies of deep liver lesions compared to superficial lesions (DLP 679 ± 285 mGy cm vs. 497 ± 167 mGy cm,p= 0.0046). No significant dose differences were observed for differences in lesion or needle size. With helical CT spirals additional to the biopsy-guiding axial CT scans, radiation exposure was significantly increased: 797 ± 287 mGy cm vs. 495 ± 162 mGy cm,p< 0.0001. The local DRL is CTDIvol9.91 mGy, DLP 542 mGy cm. Radiation dose is significantly increased in biopsies of deeper liver lesions compared with superficial lesions. Interventions with additional biopsy-guiding CT spirals lead to higher radiation doses. This study provides a detailed analysis of local radiation doses for CT-guided liver biopsies and provides a benchmark for optimising radiation protection in interventional radiology.

Parents under stress: Evaluating emergency childcare policies during the first COVID-19 lockdown in Germany.

What are the effects of school and daycare facility closures during the COVID-19 pandemic on parental well-being and parenting behavior? Can emergency childcare policies during a pandemic mitigate increases in parental stress and negative parenting behavior? To answer these questions, this study leverages cross-state variation in emergency childcare eligibility rules during the first COVID-19 lockdown in Germany and draws on unique data from the 2019 and 2020 waves of the German AID:A family panel. Employing a triple-differences approach we identify short- to medium-term intention-to-treat effects and find that while emergency care policies did not considerably affect parents' life satisfaction, partnership satisfaction or mental health, they have been effective in diminishing harsh parenting behavior. We find partly gendered effects, specifically on paternal parenting behavior. Our results suggest that decreasing parental well-being likely constitutes a general effect of the pandemic, whereas the observed increase in negative and potentially harmful parenting behavior is largely directly caused by school and daycare facility closures.

Inappropriate Administration of Rabies Postexposure Prophylaxis, Cook County, Illinois, USA.

Administration of rabies postexposure prophylaxis (PEP) is expensive and time-consuming. In suburban Cook County, Illinois, USA, administration of 55.5% of PEP treatments did not follow Advisory Committee on Immunization Practices guidelines. Health department consultation lowered the odds of inappropriate PEP administration by 87%. Providers should consult their health department before prescribing PEP.

Constitutively Higher Level of GSTT2 in Esophageal Tissues From African Americans Protects Cells Against DNA Damage.

BACKGROUND & AIMS: African American and European American individuals have a similar prevalence of gastroesophageal reflux disease (GERD), yet esophageal adenocarcinoma (EAC) disproportionately affects European American individuals. We investigated whether the esophageal squamous mucosa of African American individuals has features that protect against GERD-induced damage, compared with European American individuals. METHODS: We performed transcriptional profile analysis of esophageal squamous mucosa tissues from 20 African American and 20 European American individuals (24 with no disease and 16 with Barrett's esophagus and/or EAC). We confirmed our findings in a cohort of 56 patients and analyzed DNA samples from patients to identify associated variants. Observations were validated using matched genomic sequence and expression data from lymphoblasts from the 1000 Genomes Project. A panel of esophageal samples from African American and European American subjects was used to confirm allele-related differences in protein levels. The esophageal squamous-derived cell line Het-1A and a rat esophagogastroduodenal anastomosis model for reflux-generated esophageal damage were used to investigate the effects of the DNA-damaging agent cumene-hydroperoxide (cum-OOH) and a chemopreventive cranberry proanthocyanidin (C-PAC) extract, respectively, on levels of protein and messenger RNA (mRNA). RESULTS: We found significantly higher levels of glutathione S-transferase theta 2 (GSTT2) mRNA in squamous mucosa from African American compared with European American individuals and associated these with variants within the GSTT2 locus in African American individuals. We confirmed that 2 previously identified genomic variants at the GSTT2 locus, a 37-kb deletion and a 17-bp promoter duplication, reduce expression of GSTT2 in tissues from European American individuals. The nonduplicated 17-bp promoter was more common in tissue samples from populations of African descendant. GSTT2 protected Het-1A esophageal squamous cells from cum-OOH-induced DNA damage. Addition of C-PAC increased GSTT2 expression in Het-1A cells incubated with cum-OOH and in rats with reflux-induced esophageal damage. C-PAC also reduced levels of DNA damage in reflux-exposed rat esophagi, as observed by reduced levels of phospho-H2A histone family member X. CONCLUSIONS: We found GSTT2 to protect esophageal squamous cells against DNA damage from genotoxic stress and that GSTT2 expression can be induced by C-PAC. Increased levels of GSTT2 in esophageal tissues of African American individuals might protect them from GERD-induced damage and contribute to the low incidence of EAC in this population.

Toward detection of toxoplasmosis from urine in mice using hydro-gel nanoparticles concentration and parallel reaction monitoring mass spectrometry.

Diagnosis of clinical toxoplasmosis remains a challenge, thus limiting the availability of human clinical samples. Though murine models are an approximation of human response, their definitive infection status and tissue availability make them critical to the diagnostic development process. Hydrogel mesh nanoparticles were used to concentrate antigen to detectable levels for mass spectrometry. Seven Toxoplasma gondii isolates were used to develop a panel of potential peptide sequences for detection by parallel reaction monitoring (PRM) mass spectrometry. Nanoparticles were incubated with decreasing concentrations of tachyzoite lysate to explore the limits of detection of PRM. Mice whose toxoplasmosis infection status was confirmed by quantitative real-time PCR had urine tested by PRM after hydrogel mesh concentration for known T. gondii peptides. Peptides from GRA1, GRA12, ROP4, ROP5, SAG1, and SAG2A proteins were detected by PRM after nanoparticle concentration of urine, confirming detection of T. gondii antigen in the urine of an infected mouse.

Bruton's Tyrosine Kinase Synergizes with Notch2 To Govern Marginal Zone B Cells in Nonobese Diabetic Mice.

Expansion of autoimmune-prone marginal zone (MZ) B cells has been implicated in type 1 diabetes. To test disease contributions of MZ B cells in NOD mice, Notch2 haploinsufficiency (Notch2(+/-)) was introduced but failed to eliminate the MZ, as it does in C57BL/6 mice. Notch2(+/-)/NOD have MZ B cell numbers similar to those of wild-type C57BL/6, yet still develop diabetes. To test whether BCR signaling supports Notch2(+/-)/NOD MZ B cells, Bruton's tyrosine kinase (Btk) deficiency was introduced. Surprisingly, MZ B cells failed to develop in Btk-deficient Notch2(+/-)/NOD mice. Expression of Notch2 and its transcriptional target, Hes5, was increased in NOD MZ B cells compared with C57BL/6 MZ B cells. Btk deficiency reduced Notch2(+/-) signaling exclusively in NOD B cells, suggesting that BCR signaling enhances Notch2 signaling in this autoimmune model. The role of BCR signaling was further investigated using an anti-insulin transgenic (Tg) BCR (125Tg). Anti-insulin B cells in 125Tg/Notch2(+/-)/NOD mice populate an enlarged MZ, suggesting that low-level BCR signaling overcomes reliance on Notch2. Tracking clonotypes of anti-insulin B cells in H chain-only VH125Tg/NOD mice showed that BTK-dependent selection into the MZ depends on strength of antigenic binding, whereas Notch2-mediated selection does not. Importantly, anti-insulin B cell numbers were reduced by Btk deficiency, but not Notch2 haploinsufficiency. These studies show that 1) Notch2 haploinsufficiency limits NOD MZ B cell expansion without preventing type 1 diabetes, 2) BTK supports the Notch2 pathway in NOD MZ B cells, and 3) autoreactive NOD B cell survival relies on BTK more than Notch2, regardless of MZ location, which may have important implications for disease-intervention strategies.

Bruton's tyrosine kinase promotes persistence of mature anti-insulin B cells.

Autoreactive B lymphocytes are essential for the development of T cell-mediated type 1 diabetes (T1D). Cytoplasmic Bruton's tyrosine kinase (BTK) is a key component of B cell signaling, and its deletion in T1D-prone NOD mice significantly reduces diabetes. However, the role of BTK in the survival and function of autoreactive B cells is not clear. To evaluate the contributions of BTK, we used mice in which B cells express an anti-insulin BCR (125Tg) and promote T1D, despite being anergic. Crossing Btk deficiency onto 125Tg mice reveals that, in contrast to immature B cells, mature anti-insulin B cells are exquisitely dependent upon BTK, because their numbers are reduced by 95%. BTK kinase domain inhibition reproduces this effect in mature anti-insulin B cells, with less impact at transitional stages. The increased dependence of anti-insulin B cells on BTK became particularly evident in an Igκ locus site-directed model, in which 50% of B cells edit their BCRs to noninsulin specificities; Btk deficiency preferentially depletes insulin binders from the follicular and marginal zone B cell subsets. The persistent few Btk-deficient anti-insulin B cells remain competent to internalize Ag and invade pancreatic islets. As such, loss of BTK does not significantly reduce diabetes incidence in 125Tg/NOD mice as it does in NOD mice with a normal B cell repertoire. Thus, BTK targeting may not impair autoreactive anti-insulin B cell function, yet it may provide protection in an endogenous repertoire by decreasing the relative availability of mature autoreactive B cells.

Layered Screening and Contact-Limiting Interventions Are Necessary to Reduce SARS-Cov-2 Outbreak Risks in Large Urban Jails.

Highly transmissible infections with short serial intervals, such as SARS-Cov-2 and influenza, can quickly overwhelm healthcare resources in institutional settings such as jails. We assessed the impact of intake screening measures on the risk of SARS-CoV-2 outbreaks in this setting. We identified which elements of the intake process created the largest reductions in caseload. We implemented an individual-based simulation representative of SARS-Cov-2 transmission in a large urban jail utilizing testing at entry, quarantine, and post-quarantine testing to protect its general population from mass infection. We tracked the caseload under each scenario and quantified the impact of screening steps by varying quarantine duration, removing testing, and using a range of test sensitivities. We repeated the simulations under a range of transmissibility and community prevalence levels to evaluate the sensitivity of our results. We found that brief quarantine of newly incarcerated individuals separate from the existing population of the jail to permit pre-quarantine and end-of-quarantine tests reduced SARS-CoV-2 caseload 30-70% depending on test sensitivity. These results were robust to variation in the transmissibility. Further quarantine (up to 14 days) on average created only a 5% further reduction in caseload. A multilayered intake process is necessary to limit the spread of highly transmissible pathogens with short serial intervals. The pre-symptomatic phase means that no single strategy can be effective. We also show that shorter durations of quarantine combined with testing can be nearly as effective at preventing spread as longer-duration quarantine up to 14 days.

Adipopenia in body composition analysis: a promising imaging biomarker and potential predictive factor for patients undergoing transjugular intrahepatic portosystemic shunt placement.

OBJECTIVE: Body tissue composition plays a crucial role in the multisystemic processes of advanced liver disease and has been shown to be influenced by transjugular intrahepatic portosystemic shunt (TIPS). A differentiated analysis of the various tissue compartments has not been performed until now. The purpose of this study was to evaluate the value of imaging biomarkers derived from automated body composition analysis (BCA) to predict clinical and functional outcome. METHODS: A retrospective analysis of 56 patients undergoing TIPS procedure between 2013 and 2021 was performed. BCA on the base of pre-interventional CT examination was used to determine quantitative data as well as ratios of bone, muscle and fat masses. Furthermore, a BCA-derived sarcopenia marker was investigated. Regarding potential correlations between BCA imaging biomarkers and the occurrence of hepatic encephalopathy (HE) as well as 1-year survival, an exploratory analysis was conducted. RESULTS: No BCA imaging biomarker was associated with the occurrence of HE after TIPS placement. However, there were significant differences in alive and deceased patients regarding the BCA-derived sarcopenia marker (alive: 1.60, deceased: 1.83, p = 0.046), ratios of intra- and intermuscular fat/skeletal volume (alive: 0.53, deceased: 0.31, p = 0.015) and intra- and intermuscular fat/muscle volume (alive: 0.21, deceased: 0.14, p = 0.031). CONCLUSION: A lower amount of intra- and intermuscular adipose tissue might have protective effects regarding liver derived complications and survival. ADVANCES IN KNOWLEDGE: Precise characterization of body tissue components with automated BCA might provide prognostic information in patients with advanced liver disease undergoing TIPS procedure.

AI co-pilot: content-based image retrieval for the reading of rare diseases in chest CT.

The aim of the study was to evaluate the impact of the newly developed Similar patient search (SPS) Web Service, which supports reading complex lung diseases in computed tomography (CT), on the diagnostic accuracy of residents. SPS is an image-based search engine for pre-diagnosed cases along with related clinical reference content ( https://eref.thieme.de ). The reference database was constructed using 13,658 annotated regions of interest (ROIs) from 621 patients, comprising 69 lung diseases. For validation, 50 CT scans were evaluated by five radiology residents without SPS, and three months later with SPS. The residents could give a maximum of three diagnoses per case. A maximum of 3 points was achieved if the correct diagnosis without any additional diagnoses was provided. The residents achieved an average score of 17.6 ± 5.0 points without SPS. By using SPS, the residents increased their score by 81.8% to 32.0 ± 9.5 points. The improvement of the score per case was highly significant (p = 0.0001). The residents required an average of 205.9 ± 350.6 s per case (21.9% increase) when SPS was used. However, in the second half of the cases, after the residents became more familiar with SPS, this increase dropped to 7%. Residents' average score in reading complex chest CT scans improved by 81.8% when the AI-driven SPS with integrated clinical reference content was used. The increase in time per case due to the use of the SPS was minimal.

Clinical and Metagenomic Characterization of Neurological Infections of People With Human Immunodeficiency Virus in the Peruvian Amazon.

Background: Neurological opportunistic infections cause significant morbidity and mortality in people with human immunodeficiency virus (HIV) but are difficult to diagnose. Methods: One hundred forty people with HIV with acute neurological symptoms from Iquitos, Peru, were evaluated for cerebral toxoplasmosis with quantitative polymerase chain reaction (qPCR) of cerebrospinal fluid (CSF) and for cryptococcal meningitis with cryptococcal antigen test (CrAg) in serum or CSF. Differences between groups were assessed with standard statistical methods. A subset of samples was evaluated by metagenomic next-generation sequencing (mNGS) of CSF to compare standard diagnostics and identify additional diagnoses. Results: Twenty-seven participants were diagnosed with cerebral toxoplasmosis by qPCR and 13 with cryptococcal meningitis by CrAg. Compared to participants without cerebral toxoplasmosis, abnormal Glasgow Coma Scale score (P = .05), unilateral focal motor signs (P = .01), positive Babinski reflex (P = .01), and multiple lesions on head computed tomography (CT) (P = .002) were associated with cerebral toxoplasmosis. Photophobia (P = .03) and absence of lesions on head CT (P = .02) were associated with cryptococcal meningitis. mNGS of 42 samples identified 8 cases of cerebral toxoplasmosis, 7 cases of cryptococcal meningitis, 5 possible cases of tuberculous meningitis, and incidental detections of hepatitis B virus (n = 1) and pegivirus (n = 1). mNGS had a positive percentage agreement of 71% and a negative percentage agreement of 91% with qPCR for T gondii. mNGS had a sensitivity of 78% and specificity of 100% for Cryptococcus diagnosis. Conclusions: An infection was diagnosed by any method in only 34% of participants, demonstrating the challenges of diagnosing neurological opportunistic infections in this population and highlighting the need for broader, more sensitive diagnostic tests for central nervous system infections.

Embolization of active arterial bleeding in COVID-19 patients: A multicenter study.

PURPOSE: The purpose of this study was to assess the efficacy of transarterial embolization in COVID-19 patients with an arterial bleeding and to investigate differences between various patient groups concerning survival. METHOD: We retrospectively reviewed COVID-19 patients undergoing transarterial embolization due to an arterial bleeding in a multicenter study from April 2020 to July 2022 and analyzed the technical success of embolization and survival rate. 30-day survival between various patient groups was analyzed. The Chi- square test and Fisher's exact test were used for testing association between the categorical variables. RESULTS: 53 COVID-19 patients (age: 57.3 ± 14.3 years, 37 male) received 66 angiographies due to an arterial bleeding. The initial embolization was technically successful in 98.1% (52/53). In 20.8% (11/53) of patients, additional embolization was necessary due to a new arterial bleeding. A majority of 58.5% (31/53) had a severe course of COVID-19 infection necessitating ECMO-therapy and 86.8% (46/53) of patients received anticoagulation. 30-day survival rate in patients with ECMO-therapy was significantly lower than without ECMO-therapy (45.2% vs. 86.4%, p = 0.004). Patients with anticoagulation did not have a lower 30-day survival rate than without anticoagulation (58.7% vs. 85.7%, p = 0.23). COVID-19 patients with ECMO-therapy developed more frequently a re-bleeding after embolization than non-ECMO-patients (32.3% vs. 4.5%, p = 0.02). CONCLUSIONS: Transarterial embolization is a feasible, safe, and effective procedure in COVID-19 patients with arterial bleeding. ECMO-patients have a lower 30-day survival rate than non-ECMO-patients and have an increased risk for re-bleeding. Treatment with anticoagulation could not be identified as a risk factor for higher mortality.

Reversible occlusion of the pulmonary vasculature by transarterial embolisation with degradable starch microspheres: preclinical assessment in a human isolated lung perfusion model.

BACKGROUND: Transpulmonary embolisation (TPE) using degradable starch microspheres (DSM) is a potential approach to treat pulmonary metastases. However, there is a paucity of detailed information on perfusion dynamics. The aim of this study was to establish a human ex vivo isolated lung perfusion (ILP) model to observe and evaluate the effects of DSM-TPE in a near-physiologic setting. METHODS: ILP was carried out on six surgically resected lung lobes. At baseline, computed tomography (CT), including CT perfusion imaging (CTPI), and histopathological sampling were performed (t30). DSM-TPE was initiated and increased stepwise (t45, t60, t75, and t90) to be followed by CT imaging, histopathological sampling, and pulmonary arterial pressure (PAP). After the last assessment (t90), alpha-amylase was injected into the pulmonary artery to allow for DSM hydrolysation and two additional assessments (t105; t120). Histopathological specimens were evaluated using a semiquantitative ordinal score. CTPI was used for time to peak (TTP) analysis. RESULTS: After DSM administration, PAP and TTP increased significantly: PAP slope 95% confidence interval (CI) 0.104-0.483, p = 0.004; TTP t30 versus t45, p = 0.046. After the addition of alpha-amylase, functional parameters reverted to values comparable to baseline. In histopathological samples, embolisation grades increased significantly until t90 (slope 95% CI 0.027-0.066, p < 0.001) and decreased after addition of alpha-amylase (slope 95% CI -0.060-0.012, p = 0.165), CONCLUSIONS: The ILP model demonstrated successfully both the physiologic effect of DSM-TPE on human lungs and its reversibility with alpha-amylase. Thus, it can be used as a near-physiologic preclinical tool to simulate and assess later clinical approaches.

Is preoperative CT-guided biopsy a valuable tool in the diagnostic workup of patients with visceral and retroperitoneal sarcoma?

PURPOSE: We aimed to analyze the diagnostic accuracy of preoperative CT-guided biopsy to identify patients that might profit from neoadjuvant chemotherapy in a specialized high-volume sarcoma center. MATERIAL AND METHODS: We retrospectively reviewed all patients with suspected soft tissue tumors of the abdomen cavity including the retroperitoneum, who received CT-guided biopsy followed by surgical tumor resection. Sensitivity, specificity, PPV and NPV were calculated in all patients with abdominal sarcomas at our hospital. A subgroup analysis was performed for patients with liposarcoma. RESULTS: A total of 82 patients (35 female, 47 male, age: 62.0 ± 14.7) received preoperative CT-guided biopsy followed by surgical resection. Overall accordance of CT-guided biopsy to identify final histology was 77 %. CT-guided biopsy revealed the diagnosis of liposarcoma in 23 patients whereas final analysis of the surgical specimen identified liposarcoma in 29 patients. Here, sensitivity, specificity, PPV and NPV was 79.3 %, 100.0 %, 100.0 % and 89.8 % respectively. Subgroup analysis revealed a better accuracy for correctly identifying patients with well-differentiated liposarcoma than patients with dedifferentiated liposarcoma (75.0 % vs 62.5 %). In patients with other sarcoma, sensitivity, specificity, PPV, NPV and diagnostic accuracy was 87.5 %, 95.5 %, 82.4 % and 96.9 %, respectively. CONCLUSION: CT-guided biopsy in a specialized high-volume sarcoma center is an accurate and effective method to assess patients with abdominal sarcoma and especially abdominal liposarcoma. Therefore, it is an indispensable tool in the pretherapeutic workup process. Nevertheless, our study underlines the previously reported difficulties in dedifferentiated liposarcoma diagnostics, whereby these patient cohort would profit the most from a neoadjuvant therapy regime.

Effectiveness of DBT skills training in outpatient men: A naturalistic study.

A plethora of research highlights the effectiveness of dialectical behavioral therapy (DBT) in improving emotion regulation and psychological functioning transdiagnostically. However, the majority of this research has focused on women, and the limited existing research on men has concentrated on high acuity patients in forensic and inpatient settings. The present study examined the effectiveness of DBT skills groups in reducing emotion regulation difficulties in a transdiagnostic sample of adult men in a university-based clinical outpatient setting using a naturalistic design. Sixteen adult male patients completed self-report measures examining emotion regulation difficulties (Difficulties in Emotion Regulation Scale) at intake and following one 12-week module of DBT skills group. Men showed a significant reduction in overall difficulty regulating emotions with a moderate effect size (d = 0.63, p < .05) following one module of DBT skills group, which were accounted for primarily by improvements on the impulse control difficulties subscale (d = 1.06, p < .01). In comparison, women (N = 82) showed significant improvements in global emotion regulation difficulties (d = 0.71, p < .01), with marked improvement across all six subscales. Implications of findings for the application of DBT for men in outpatient settings is discussed, limitations reviewed, and areas for future research suggested. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Should routine risk reduction procedures for the prevention and control of pandemics become a standard in all oncological outpatient clinics? The prospective COVID-19 cohort study: protect-CoV.

Limited knowledge exists on the effectiveness of preventive preparedness plans for the care of outpatient cancer patients during epidemics or pandemics. To ensure adequate, timely and continuous clinical care for this highly vulnerable population, we propose the establishment of preventive standard safety protocols providing effective early phase identification of outbreaks at outpatient cancer facilities and communicating adapted standards of care. The prospective cohort study Protect-CoV conducted at the LMU Klinikum from mid-March to June 2020 investigated the effectiveness of a rapid, proactive and methodical response to protect patients and interrupt SARS-CoV-2 transmission chains during the first pandemic wave. The implemented measures reduced the risk of infection of individual cancer patients and ensured safe adjunctive infusion therapy in an outpatient setting during the early COVID-19 pandemic. In addition to the immediate implementation of standard hygiene procedures, our results underscore the importance of routine PCR testing for the identification of asymptomatic or pre-symptomatic COVID-19 cases and immediate tracing of positive cases and their contacts. While more prospective controlled studies are needed to confirm these results, our study illustrates the importance of including preventative testing and tracing measures in the standard risk reduction procedures at all out patient cancer centers.

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles.

BACKGROUND: Diagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) for Toxoplasma in blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment. METHOLOGY/PRINCIPLE FINDINGS: Here we describe proof of concept for a novel urine diagnostics for TE using Poly-N-Isopropylacrylamide nanoparticles dyed with Reactive Blue-221 to concentrate antigens, substantially increasing the limit of detection. After nanoparticle-concentration, a standard western blotting technique with a monoclonal antibody was used for antigen detection. Limit of detection was 7.8pg/ml and 31.3pg/ml of T. gondii antigens GRA1 and SAG1, respectively. To characterize this diagnostic approach, 164 hospitalized HIV-infected patients with neurological symptoms compatible with TE were tested for 1) T. gondii serology (121/147, positive samples/total samples tested), 2) qPCR in cerebrospinal fluid (11/41), 3) qPCR in blood (10/112), and 4) urinary GRA1 (30/164) and SAG1 (12/164). GRA1 appears to be superior to SAG1 for detection of TE antigens in urine. Fifty-one HIV-infected, T. gondii seropositive but asymptomatic persons all tested negative by nanoparticle western blot and blood qPCR, suggesting the test has good specificity for TE for both GRA1 and SAG1. In a subgroup of 44 patients, urine samples were assayed with mass spectrometry parallel-reaction-monitoring (PRM) for the presence of T. gondii antigens. PRM identified antigens in 8 samples, 6 of which were concordant with the urine diagnostic. CONCLUSION/SIGNIFICANCES: Our results demonstrate nanoparticle technology's potential for a noninvasive diagnostic test for TE. Moving forward, GRA1 is a promising target for antigen based diagnostics for TE.

Homologous Recombination in Clostridioides difficile Mediates Diversification of Cell Surface Features and Transport Systems.

Illness caused by the pathogen Clostridioides difficile is widespread and can range in severity from mild diarrhea to sepsis and death. Strains of C. difficile isolated from human infections exhibit great genetic diversity, leading to the hypothesis that the genetic background of the infecting strain at least partially determines a patient's clinical course. However, although certain strains of C. difficile have been suggested to be associated with increased severity, strain typing alone has proved insufficient to explain infection severity. The limited explanatory power of strain typing has been hypothesized to be due to genetic variation within strain types, as well as genetic elements shared between strain types. Homologous recombination is an evolutionary mechanism that can result in large genetic differences between two otherwise clonal isolates, and also lead to convergent genotypes in distantly related strains. More than 400 C. difficile genomes were analyzed here to assess the effect of homologous recombination within and between C. difficile clades. Almost three-quarters of single nucleotide variants in the C. difficile phylogeny are predicted to be due to homologous recombination events. Furthermore, recombination events were enriched in genes previously reported to be important to virulence and host-pathogen interactions, such as flagella, cell wall proteins, and sugar transport and metabolism. Thus, by exploring the landscape of homologous recombination in C. difficile, we identified genetic loci whose elevated rates of recombination mediated diversification, making them strong candidates for being mediators of host-pathogen interaction in diverse strains of C. difficileIMPORTANCE Infections with C. difficile result in up to half a million illnesses and tens of thousands of deaths annually in the United States. The severity of C. difficile illness is dependent on both host and bacterial factors. Studying the evolutionary history of C. difficile pathogens is important for understanding the variation in pathogenicity of these bacteria. This study examines the extent and targets of homologous recombination, a mechanism by which distant strains of bacteria can share genetic material, in hundreds of C. difficile strains and identifies hot spots of realized recombination events. The results of this analysis reveal the importance of homologous recombination in the diversification of genetic loci in C. difficile that are significant in its pathogenicity and host interactions, such as flagellar construction, cell wall proteins, and sugar transport and metabolism.

Clinical Utility of a Highly Sensitive Lateral Flow Immunoassay as determined by Titer Analysis for the Detection of anti-SARS-CoV-2 Antibodies at the Point-of-Care.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), became a pandemic in early 2020. Lateral flow immunoassays for antibody testing have been viewed as a cheap and rapidly deployable method for determining previous infection with SARS-CoV-2; however, these assays have shown unacceptably low sensitivity. We report on nine lateral flow immunoassays currently available and compare their titer sensitivity in serum to a best-practice enzyme-linked immunosorbent assay (ELISA) and viral neutralization assay. For a small group of PCR-positive, we found two lateral flow immunoassay devices with titer sensitivity roughly equal to the ELISA; these devices were positive for all PCR-positive patients harboring SARS-CoV-2 neutralizing antibodies. One of these devices was deployed in Northern Italy to test its sensitivity and specificity in a real-world clinical setting. Using the device with fingerstick blood on a cohort of 27 hospitalized PCR-positive patients and seven hospitalized controls, ROC curve analysis gave AUC values of 0.7646 for IgG. For comparison, this assay was also tested with saliva from the same patient population and showed reduced discrimination between cases and controls with AUC values of 0.6841 for IgG. Furthermore, during viral neutralization testing, one patient was discovered to harbor autoantibodies to ACE2, with implications for how immune responses are profiled. We show here through a proof-of-concept study that these lateral flow devices can be as analytically sensitive as ELISAs and adopted into hospital protocols; however, additional improvements to these devices remain necessary before their clinical deployment.

Lipoarabinomannan antigenic epitope differences in tuberculosis disease subtypes.

An accurate urine test for diverse populations with active tuberculosis could be transformative for preventing TB deaths. Urinary liporabinomannan (LAM) testing has been previously restricted to HIV co-infected TB patients. In this study we evaluate urinary LAM in HIV negative, pediatric and adult, pulmonary and extrapulmonary tuberculosis patients. We measured 430 microbiologically confirmed pretreatment tuberculosis patients and controls from Peru, Guinea Bissau, Venezuela, Uganda and the United States using three monoclonal antibodies, MoAb1, CS35, and A194, which recognize distinct LAM epitopes, a one-sided immunoassay, and blinded cohorts. We evaluated sources of assay variability and comorbidities (HIV and diabetes). All antibodies successfully discriminated TB positive from TB negative patients. ROAUC from the average of three antibodies' responses was 0.90; 95% CI 0.87-0.93, 90% sensitivity, 73.5% specificity (80 pg/mL). MoAb1, recognizing the 5-methylthio-D-xylofuranose(MTX)-mannose(Man) cap epitope, performed the best, was less influenced by glycosuria and identified culture positive pediatric (N = 19) and extrapulmonary (N = 24) patients with high accuracy (ROAUC 0.87, 95% CI 0.77-0.98, 0.90 sensitivity 0.80 specificity at 80 pg/mL; ROAUC = 0.96, 95% CI 0.92-0.99, 96% sensitivity, 80% specificity at 82 pg/mL, respectively). The MoAb1 antibody, recognizing the MTX-Man cap epitope, is a novel analyte for active TB detection in pediatric and extrapulmonary disease.