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1.
Chem Sci ; 2024 Sep 06.
Article in English | MEDLINE | ID: mdl-39309093

ABSTRACT

Exploiting the potential of curcuminoids (CCMoids) as molecular platforms, a new 3.53 nm extended system (pyACCMoid, 2) has been designed in two steps by reacting a CCMoid with amino-terminal groups (NH2-CCMoid, 1, of 1.79 nm length) with polycyclic aromatic hydrocarbon (PAH) aldehydes. CCMoid 2 contains pyrene units at both ends as anchoring groups to optimize its trapping in graphene nano-junctions created by feedback-controlled electro-burning. The measured I-V characteristics show gate-dependent behaviour at room temperature and 10 K, with increased conductance values compared to shorter CCMoids previously reported, and in agreement with DFT calculations. Our results show that the adjusted molecular design improves the conductance, as system 2 separates the conductive backbone from the anchor groups, which tend to adopt a planar configuration upon contact with the graphene electrodes. DFT calculations using Green functions of a set of different molecular conformations of 2 on graphene electrodes show a direct relationship between the units (e.g. pyrene, amide, etc.), in the molecule, through which electrons are injected and the conductance values; where the size of the spacing between the graphene electrodes contributes but is not the dominant factor, and thus, counter-intuitively the smallest spacing gives one of the lowest conductance values.

2.
ACS Nano ; 18(39): 26514-26521, 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-39304184

ABSTRACT

Open-shell polycyclic aromatic hydrocarbons (PAHs) represent promising building blocks for carbon-based functional magnetic materials. Their magnetic properties stem from the presence of unpaired electrons localized in radical states of π character. Consequently, these materials are inclined to exhibit spin delocalization, form extended collective states, and respond to the flexibility of the molecular backbones. However, they are also highly reactive, requiring structural strategies to protect the radical states from reacting with the environment. Here, we demonstrate that the open-shell ground state of the diradical 2-OS survives on a Au(111) substrate as a global singlet formed by two unpaired electrons with antiparallel spins coupled through a conformational-dependent interaction. The 2-OS molecule is a "protected" derivative of the Chichibabin's diradical, featuring a nonplanar geometry that destabilizes the closed-shell quinoidal structure. Using scanning tunneling microscopy (STM), we localized the two interacting spins at the molecular edges, and detected an excited triplet state a few millielectronvolts above the singlet ground state. Mean-field Hubbard simulations reveal that the exchange coupling between the two spins strongly depends on the torsional angles between the different molecular moieties, suggesting the possibility of influencing the molecule's magnetic state through structural changes. This was demonstrated here using the STM tip to manipulate the molecular conformation, while simultaneously detecting changes in the spin excitation spectrum. Our work suggests the potential of these PAHs as all-carbon spin-crossover materials.

3.
Article in English | MEDLINE | ID: mdl-39158991

ABSTRACT

The soybean cyst nematode (SCN; Heterodera glycines) facilitates infection by secreting a repertoire of effector proteins into host cells to establish a permanent feeding site composed of a syncytium of root cells. Among the diverse proteins secreted by the nematode, we were specifically interested in identifying proteases to pursue our goal of engineering decoy substrates that elicit an immune response when cleaved by an SCN protease. We identified a cysteine protease that we named Cysteine Protease 1 (CPR1), which was predicted to be a secreted effector based on transcriptomic data obtained from SCN esophageal gland cells, presence of a signal peptide, and lack of transmembrane domains. CPR1 is conserved in all isolates of SCN sequenced to date, suggesting it is critical for virulence. Transient expression of CPR1 in Nicotiana benthamiana leaves suppressed cell death induced by a constitutively active nucleotide binding leucine-rich repeat protein, RPS5, indicating that CPR1 inhibits effector-triggered immunity. CPR1 localizes in part to the mitochondria when expressed in planta. Proximity-based labeling in transgenic soybean roots, co-immunoprecipitation, and cleavage assays identified a branched-chain amino acid aminotransferase from soybean (GmBCAT1) as a substrate of CPR1. Consistent with this, GmBCAT1 also localizes to mitochondria. Silencing of the CPR1 transcript in the nematode reduced penetration frequency in soybean roots while the expression of CPR1 in soybean roots enhanced susceptibility. Our data demonstrates that CPR1 is a conserved effector protease with a direct target in soybean roots, highlighting it as a promising candidate for decoy engineering.

4.
Eur Radiol Exp ; 8(1): 86, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39090457

ABSTRACT

BACKGROUND: To investigate the reproducibility of automated volumetric bone mineral density (vBMD) measurements from routine thoracoabdominal computed tomography (CT) assessed with segmentations by a convolutional neural network and automated correction of contrast phases, on diverse scanners, with scanner-specific asynchronous or scanner-agnostic calibrations. METHODS: We obtained 679 observations from 278 CT scans in 121 patients (77 males, 63.6%) studied from 04/2019 to 06/2020. Observations consisted of two vBMD measurements from Δdifferent reconstruction kernels (n = 169), Δcontrast phases (n = 133), scan Δsessions (n = 123), Δscanners (n = 63), or Δall of the aforementioned (n = 20), and observations lacking scanner-specific calibration (n = 171). Precision was assessed using root-mean-square error (RMSE) and root-mean-square coefficient of variation (RMSCV). Cross-measurement agreement was assessed using Bland-Altman plots; outliers within 95% confidence interval of the limits of agreement were reviewed. RESULTS: Repeated measurements from Δdifferent reconstruction kernels were highly precise (RMSE 3.0 mg/cm3; RMSCV 1.3%), even for consecutive scans with different Δcontrast phases (RMSCV 2.9%). Measurements from different Δscan sessions or Δscanners showed decreased precision (RMSCV 4.7% and 4.9%, respectively). Plot-review identified 12 outliers from different scan Δsessions, with signs of hydropic decompensation. Observations with Δall differences showed decreased precision compared to those lacking scanner-specific calibration (RMSCV 5.9 and 3.7, respectively). CONCLUSION: Automatic vBMD assessment from routine CT is precise across varying setups, when calibrated appropriately. Low precision was found in patients with signs of new or worsening hydropic decompensation, what should be considered an exclusion criterion for both opportunistic and dedicated quantitative CT. RELEVANCE STATEMENT: Automated CT-based vBMD measurements are precise in various scenarios, including cross-session and cross-scanner settings, and may therefore facilitate opportunistic screening for osteoporosis and surveillance of BMD in patients undergoing routine clinical CT scans. KEY POINTS: Artificial intelligence-based tools facilitate BMD measurements in routine clinical CT datasets. Automated BMD measurements are highly reproducible in various settings. Reliable, automated opportunistic osteoporosis diagnostics allow for large-scale application.


Subject(s)
Bone Density , Tomography, X-Ray Computed , Humans , Male , Tomography, X-Ray Computed/methods , Female , Reproducibility of Results , Middle Aged , Aged , Adult , Aged, 80 and over , Retrospective Studies , Neural Networks, Computer
5.
Phytopathology ; : PHYTO03240095R, 2024 Oct 04.
Article in English | MEDLINE | ID: mdl-38976643

ABSTRACT

Soybean cyst nematode (SCN, Heterodera glycines) is most effectively managed through planting resistant soybean cultivars, but the repeated use of the same resistance sources has led to a widespread emergence of virulent SCN populations that can overcome soybean resistance. Resistance to SCN HG type 0 (Race 3) in soybean cultivar Forrest is mediated by an epistatic interaction between the soybean resistance genes rhg1-a and Rhg4. We previously developed two SCN inbred populations by mass-selecting SCN HG type 0 (Race 3) on susceptible and resistant recombinant inbred lines, derived from a cross between Forrest and the SCN-susceptible cultivar Essex, which differ for Rhg4. To identify SCN genes potentially involved in overcoming rhg1-a/Rhg4-mediated resistance, we conducted RNA sequencing on early parasitic juveniles of these two SCN inbred populations infecting their respective hosts, only to discover a handful of differentially expressed genes (DEGs). However, in a comparison with early parasitic juveniles of an avirulent SCN inbred population infecting a resistant host, we discovered 59 and 171 DEGs uniquely up- or downregulated in virulent parasitic juveniles adapted on the resistant host. Interestingly, the proteins coded by these 59 DEGs included vitamin B-associated proteins (reduced folate carrier, biotin synthase, and thiamine transporter) and nematode effectors known to play roles in plant defense suppression, suggesting that virulent SCN may exert a heightened transcriptional response to cope with enhanced plant defenses and an altered nutritional status of a resistant soybean host. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

6.
PLoS Pathog ; 20(7): e1012395, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39074142

ABSTRACT

Plant-parasitic nematodes constrain global food security. During parasitism, they secrete effectors into the host plant from two types of pharyngeal gland cells. These effectors elicit profound changes in host biology to suppress immunity and establish a unique feeding organ from which the nematode draws nutrition. Despite the importance of effectors in nematode parasitism, there has been no comprehensive identification and characterisation of the effector repertoire of any plant-parasitic nematode. To address this, we advance techniques for gland cell isolation and transcriptional analysis to define a stringent annotation of putative effectors for the cyst nematode Heterodera schachtii at three key life-stages. We define 717 effector gene loci: 269 "known" high-confidence homologs of plant-parasitic nematode effectors, and 448 "novel" effectors with high gland cell expression. In doing so we define the most comprehensive "effectorome" of a plant-parasitic nematode to date. Using this effector definition, we provide the first systems-level understanding of the origin, deployment and evolution of a plant-parasitic nematode effectorome. The robust identification of the effector repertoire of a plant-parasitic nematode will underpin our understanding of nematode pathology, and hence, inform strategies for crop protection.


Subject(s)
Host-Parasite Interactions , Plant Diseases , Animals , Plant Diseases/parasitology , Tylenchoidea/genetics , Plants/parasitology , Helminth Proteins/genetics , Helminth Proteins/metabolism , Nematoda/genetics
8.
Radiologie (Heidelb) ; 64(8): 653-662, 2024 Aug.
Article in German | MEDLINE | ID: mdl-38639916

ABSTRACT

BACKGROUND: Magnetic resonance (MRI) imaging of the skeletal muscles (muscle MRI for short) is increasingly being used in clinical routine for diagnosis and longitudinal assessment of muscle disorders. However, cross-centre standards for measurement protocol and radiological assessment are still lacking. OBJECTIVES: The aim of this expert recommendation is to present standards for the application and interpretation of muscle MRI in hereditary and inflammatory muscle disorders. METHODS: This work was developed in collaboration between neurologists, neuroradiologists, radiologists, neuropaediatricians, neuroscientists and MR physicists from different university hospitals in Germany. The recommendations are based on expert knowledge and a focused literature search. RESULTS: The indications for muscle MRI are explained, including the detection and monitoring of structural tissue changes and oedema in the muscle, as well as the identification of a suitable biopsy site. Recommendations for the examination procedure and selection of appropriate MRI sequences are given. Finally, steps for a structured radiological assessment are presented. CONCLUSIONS: The present work provides concrete recommendations for the indication, implementation and interpretation of muscle MRI in muscle disorders. Furthermore, it provides a possible basis for the standardisation of the measurement protocols at all clinical centres in Germany.


Subject(s)
Magnetic Resonance Imaging , Muscular Diseases , Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging/standards , Humans , Muscular Diseases/diagnostic imaging , Germany , Practice Guidelines as Topic , Muscle, Skeletal/diagnostic imaging , Muscle, Skeletal/pathology
9.
Nervenarzt ; 95(8): 721-729, 2024 Aug.
Article in German | MEDLINE | ID: mdl-38683354

ABSTRACT

BACKGROUND: Magnetic resonance (MRI) imaging of the skeletal muscles (muscle MRI for short) is increasingly being used in clinical routine for diagnosis and longitudinal assessment of muscle disorders. However, cross-centre standards for measurement protocol and radiological assessment are still lacking. OBJECTIVES: The aim of this expert recommendation is to present standards for the application and interpretation of muscle MRI in hereditary and inflammatory muscle disorders. METHODS: This work was developed in collaboration between neurologists, neuroradiologists, radiologists, neuropaediatricians, neuroscientists and MR physicists from different university hospitals in Germany. The recommendations are based on expert knowledge and a focused literature search. RESULTS: The indications for muscle MRI are explained, including the detection and monitoring of structural tissue changes and oedema in the muscle, as well as the identification of a suitable biopsy site. Recommendations for the examination procedure and selection of appropriate MRI sequences are given. Finally, steps for a structured radiological assessment are presented. CONCLUSIONS: The present work provides concrete recommendations for the indication, implementation and interpretation of muscle MRI in muscle disorders. Furthermore, it provides a possible basis for the standardisation of the measurement protocols at all clinical centres in Germany.


Subject(s)
Magnetic Resonance Imaging , Muscle, Skeletal , Magnetic Resonance Imaging/standards , Magnetic Resonance Imaging/methods , Humans , Germany , Muscle, Skeletal/diagnostic imaging , Muscle, Skeletal/pathology , Muscular Diseases/diagnostic imaging , Practice Guidelines as Topic , Radiology/standards , Neurology/standards
10.
J Cereb Blood Flow Metab ; 44(8): 1253-1270, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38483125

ABSTRACT

Arterial spin labeling (ASL) is a non-invasive magnetic resonance imaging (MRI) method for the assessment of cerebral blood flow (CBF). This review summarizes recent ASL-based investigations in adult and pediatric patients with migraine with aura, migraine without aura, and chronic migraine. A systematic search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted within PubMed and reference sections of articles identified from April 2014 to November 2022. Out of 236 initial articles, 20 remained after filtering, encompassing data from 1155 subjects in total. Cross-sectional studies in adults showed inconsistent results, while longitudinal studies demonstrated that cerebral perfusion changes over the migraine cycle can be tracked using ASL. The most consistent findings were observed in ictal states among pediatric migraine patients, where studies showed hypoperfusion matching aura symptoms during early imaging followed by hyperperfusion. Overall, ASL is a useful but currently underutilized modality for evaluating cerebral perfusion in patients with migraine. The generalizability of results is currently limited by heterogeneities regarding study design and documentation of clinical variables (e.g., relation of attacks to scanning timepoint, migraine subtypes). Future MRI studies should consider augmenting imaging protocols with ASL to further elucidate perfusion dynamics in migraine.


Subject(s)
Cerebrovascular Circulation , Migraine Disorders , Perfusion Imaging , Spin Labels , Humans , Cerebrovascular Circulation/physiology , Migraine Disorders/diagnostic imaging , Migraine Disorders/physiopathology , Perfusion Imaging/methods , Magnetic Resonance Imaging/methods , Brain/diagnostic imaging , Brain/blood supply , Brain/physiopathology , Adult
11.
Front Endocrinol (Lausanne) ; 15: 1352048, 2024.
Article in English | MEDLINE | ID: mdl-38440788

ABSTRACT

Objectives: To quantitatively investigate the age- and sex-related longitudinal changes in trabecular volumetric bone mineral density (vBMD) and vertebral body volume at the thoracolumbar spine in adults. Methods: We retrospectively included 168 adults (mean age 58.7 ± 9.8 years, 51 women) who received ≥7 MDCT scans over a period of ≥6.5 years (mean follow-up 9.0 ± 2.1 years) for clinical reasons. Level-wise vBMD and vertebral body volume were extracted from 22720 thoracolumbar vertebrae using a convolutional neural network (CNN)-based framework with asynchronous calibration and correction of the contrast media phase. Human readers conducted semiquantitative assessment of fracture status and bony degenerations. Results: In the 40-60 years age group, women had a significantly higher trabecular vBMD than men at all thoracolumbar levels (p<0.05 to p<0.001). Conversely, men, on average, had larger vertebrae with lower vBMD. This sex difference in vBMD did not persist in the 60-80 years age group. While the lumbar (T12-L5) vBMD slopes in women only showed a non-significant trend of accelerated decline with age, vertebrae T1-11 displayed a distinct pattern, with women demonstrating a significantly accelerated decline compared to men (p<0.01 to p<0.0001). Between baseline and last follow-up examinations, the vertebral body volume slightly increased in women (T1-12: 1.1 ± 1.0 cm3; L1-5: 1.0 ± 1.4 cm3) and men (T1-12: 1.2 ± 1.3 cm3; L1-5: 1.5 ± 1.6 cm3). After excluding vertebrae with bony degenerations, the residual increase was only small in women (T1-12: 0.6 ± 0.6 cm3; L1-5: 0.7 ± 0.7 cm3) and men (T1-12: 0.7 ± 0.6 cm3; L1-5: 1.2 ± 0.8 cm3). In non-degenerated vertebrae, the mean change in volume was <5% of the respective vertebral body volumes. Conclusion: Sex differences in thoracolumbar vBMD were apparent before menopause, and disappeared after menopause, likely attributable to an accelerated and more profound vBMD decline in women at the thoracic spine. In patients without advanced spine degeneration, the overall volumetric changes in the vertebral body appeared subtle.


Subject(s)
Sex Characteristics , Vertebral Body , Adult , Female , Humans , Male , Middle Aged , Aged , Bone Density , Retrospective Studies , Spine
12.
Osteoporos Int ; 35(6): 971-996, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38353706

ABSTRACT

The use of opportunistic computed tomography (CT) image-based biomarkers may be a low-cost strategy for screening older individuals at high risk for osteoporotic fractures and populations that are not sufficiently targeted. This review aimed to assess the discriminative ability of image-based biomarkers derived from existing clinical routine CT scans for hip, vertebral, and major osteoporotic fracture prediction. A systematic search in PubMed MEDLINE, Embase, Cochrane, and Web of Science was conducted from the earliest indexing date until July 2023. The evaluation of study quality was carried out using a modified Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2) checklist. The primary outcome of interest was the area under the curve (AUC) and its corresponding 95% confidence intervals (CIs) obtained for four main categories of biomarkers: areal bone mineral density (BMD), image attenuation, volumetric BMD, and finite element (FE)-derived biomarkers. The meta-analyses were performed using random effects models. Sixty-one studies were included in this review, among which 35 were synthesized in a meta-analysis and the remaining articles were qualitatively synthesized. In comparison to the pooled AUC of areal BMD (0.73 [95% CI 0.71-0.75]), the pooled AUC values for predicting osteoporotic fractures for FE-derived parameters (0.77 [95% CI 0.72-0.81]; p < 0.01) and volumetric BMD (0.76 [95% CI 0.71-0.81]; p < 0.01) were significantly higher, but there was no significant difference with the pooled AUC for image attenuation (0.73 [95% CI 0.66-0.79]; p = 0.93). Compared to areal BMD, volumetric BMD and FE-derived parameters may provide a significant improvement in the discrimination of osteoporotic fractures using opportunistic CT assessments.


Subject(s)
Biomarkers , Bone Density , Osteoporotic Fractures , Tomography, X-Ray Computed , Humans , Osteoporotic Fractures/diagnostic imaging , Osteoporotic Fractures/physiopathology , Bone Density/physiology , Tomography, X-Ray Computed/methods , Biomarkers/blood , Mass Screening/methods , Spinal Fractures/physiopathology , Spinal Fractures/diagnostic imaging , Hip Fractures/diagnostic imaging , Hip Fractures/physiopathology , Finite Element Analysis
13.
Eur Radiol ; 34(4): 2437-2444, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37691079

ABSTRACT

OBJECTIVES: MR imaging-based proton density fat fraction (PDFF) and T2* imaging has shown to be useful for the evaluation of degenerative changes in the spine. Therefore, the aim of this study was to investigate the influence of myelotoxic chemotherapy on the PDFF and T2* of the thoracolumbar spine in comparison to changes in bone mineral density (BMD). METHODS: In this study, 19 patients were included who had received myelotoxic chemotherapy (MC) and had received a MR imaging scan of the thoracolumbar vertebrates before and after the MC. Every patient was matched for age, sex, and time between the MRI scans to two controls without MC. All patients underwent 3-T MR imaging including the thoracolumbar spine comprising chemical shift encoding-based water-fat imaging to extract PDFF and T2* maps. Moreover, trabecular BMD values were determined before and after chemotherapy. Longitudinal changes in PDFF and T2* were evaluated and compared to changes in BMD. RESULTS: Absolute mean differences of PDFF values between scans before and after MC were at 8.7% (p = 0.01) and at -0.5% (p = 0.57) in the control group, resulting in significantly higher changes in PDFF in patients with MC (p = 0.008). BMD and T2* values neither showed significant changes in patients with nor in those without myelotoxic chemotherapy (p = 0.15 and p = 0.47). There was an inverse, yet non-significant correlation between changes in PDFF and BMD found in patients with myelotoxic chemotherapy (r = -0.41, p = 0.12). CONCLUSION: Therefore, PDFF could be a useful non-invasive biomarker in order to detect changes in the bone marrow in patients receiving myelotoxic therapy. CLINICAL RELEVANCE STATEMENT: Using PDFF as a non-invasive biomarker for early bone marrow changes in oncologic patients undergoing myelotoxic treatment may help enable more targeted countermeasures at commencing states of bone marrow degradation and reduce risks of possible fragility fractures. KEY POINTS: Quantifying changes in bone marrow fat fraction, as well as T2* caused by myelotoxic pharmaceuticals using proton density fat fraction, is feasible. Proton density fat fraction could potentially be established as a non-invasive biomarker for early bone marrow changes in oncologic patients undergoing myelotoxic treatment.


Subject(s)
Bone Marrow , Protons , Humans , Bone Marrow/diagnostic imaging , Spine , Magnetic Resonance Imaging/methods , Biomarkers , Adipose Tissue/diagnostic imaging
14.
Quant Imaging Med Surg ; 13(9): 5472-5482, 2023 Sep 01.
Article in English | MEDLINE | ID: mdl-37711780

ABSTRACT

Background: To investigate reproducibility of texture features and volumetric bone mineral density (vBMD) extracted from trabecular bone in the thoracolumbar spine in routine clinical multi-detector computed tomography (MDCT) data in a single scanner environment. Methods: Patients who underwent two routine clinical thoraco-abdominal MDCT exams at a single scanner with a time interval of 6 to 26 months (n=203, 131 males; time interval mean, 13 months; median, 12 months) were included in this observational study. Exclusion criteria were metabolic and hematological disorders, bone metastases, use of bone-active medications, and history of osteoporotic vertebral fractures (VFs) or prior diagnosis of osteoporosis. A convolutional neural network (CNN)-based framework was used for automated spine labeling and segmentation (T5-L5), asynchronous Hounsfield unit (HU)-to-BMD calibration, and correction for the intravenous contrast medium phase. Vertebral vBMD and six texture features [varianceglobal, entropy, short-run emphasis (SRE), long-run emphasis (LRE), run-length non-uniformity (RLN), and run percentage (RP)] were extracted for mid- (T5-T8) and lower thoracic (T9-T12), and lumbar vertebrae (L1-L5), respectively. Relative annual changes were calculated in texture features and vBMD for each vertebral level and sorted by sex, and changes were checked for statistical significance (P<0.05) using paired t-tests. Root mean square coefficient of variation (RMSCV) and root mean square error (RMSE) were calculated as measures of variability. Results: SRE, LRE, RLN, and RP exhibited substantial reproducibility with RMSCV-values below 2%, for both sexes and at all spine levels, while vBMD was less reproducible (RMSCV =11.9-16.2%). Entropy showed highest variability (RMSCV =4.34-7.69%) due to statistically significant increases [range, mean ± standard deviation: (4.40±5.78)% to (8.36±8.66)%, P<0.001]. RMSCV of varianceglobal ranged from 1.60% to 3.03%. Conclusions: Opportunistic assessment of texture features in a single scanner environment using the presented CNN-based framework yields substantial reproducibility, outperforming vBMD reproducibility. Lowest scan-rescan variability was found for higher-order texture features. Further studies are warranted to determine, whether microarchitectural changes to the trabecular bone may be assessed through texture features.

15.
Front Physiol ; 14: 1217007, 2023.
Article in English | MEDLINE | ID: mdl-37534364

ABSTRACT

Background: Dark-field imaging is a novel imaging modality that allows for the assessment of material interfaces by exploiting the wave character of x-ray. While it has been extensively studied in chest imaging, only little is known about the modality for imaging other tissues. Therefore, the purpose of this study was to evaluate whether a clinical X-ray dark-field scanner prototype allows for the assessment of osteoporosis. Materials and methods: In this prospective study we examined human cadaveric lumbar spine specimens (vertebral segments L2 to L4). We used a clinical prototype for dark-field radiography that yields both attenuation and dark-field images. All specimens were scanned in lateral orientation in vertical and horizontal position. All specimens were additionally imaged with CT as reference. Bone mineral density (BMD) values were derived from asynchronously calibrated quantitative CT measurements. Correlations between attenuation signal, dark-field signal and BMD were assessed using Spearman's rank correlation coefficients. The capability of the dark-field signal for the detection of osteoporosis/osteopenia was evaluated with receiver operating characteristics (ROC) curve analysis. Results: A total of 58 vertebrae from 20 human cadaveric spine specimens (mean age, 73 years ±13 [standard deviation]; 11 women) were studied. The dark-field signal was positively correlated with the BMD, both in vertical (r = 0.56, p < .001) and horizontal position (r = 0.43, p < .001). Also, the dark-field signal ratio was positively correlated with BMD (r = 0.30, p = .02). No correlation was found between the signal ratio of attenuation signal and BMD (r = 0.14, p = .29). For the differentiation between specimens with and without osteoporosis/osteopenia, the area under the ROC curve (AUC) was 0.80 for the dark-field signal in vertical position. Conclusion: Dark-field imaging allows for the differentiation between spine specimens with and without osteoporosis/osteopenia and may therefore be a potential biomarker for bone stability.

16.
Front Endocrinol (Lausanne) ; 14: 1207949, 2023.
Article in English | MEDLINE | ID: mdl-37529605

ABSTRACT

Objectives: To investigate vertebral osteoporotic fracture (VF) prediction by automatically extracted trabecular volumetric bone mineral density (vBMD) from routine CT, and to compare the model with fracture prevalence-based prediction models. Methods: This single-center retrospective study included patients who underwent two thoraco-abdominal CT scans during clinical routine with an average inter-scan interval of 21.7 ± 13.1 months (range 5-52 months). Automatic spine segmentation and vBMD extraction was performed by a convolutional neural network framework (anduin.bonescreen.de). Mean vBMD was calculated for levels T5-8, T9-12, and L1-5. VFs were identified by an expert in spine imaging. Odds ratios (ORs) for prevalent and incident VFs were calculated for vBMD (per standard deviation decrease) at each level, for baseline VF prevalence (yes/no), and for baseline VF count (n) using logistic regression models, adjusted for age and sex. Models were compared using Akaike's and Bayesian information criteria (AIC & BIC). Results: 420 patients (mean age, 63 years ± 9, 276 males) were included in this study. 40 (25 female) had prevalent and 24 (13 female) had incident VFs. Individuals with lower vBMD at any spine level had higher odds for VFs (L1-5, prevalent VF: OR,95%-CI,p: 2.2, 1.4-3.5,p=0.001; incident VF: 3.5, 1.8-6.9,p<0.001). In contrast, VF status (2.15, 0.72-6.43,p=0.170) and count (1.38, 0.89-2.12,p=0.147) performed worse in incident VF prediction. Information criteria revealed best fit for vBMD-based models (AIC vBMD=165.2; VF status=181.0; count=180.7). Conclusions: VF prediction based on automatically extracted vBMD from routine clinical MDCT outperforms prediction models based on VF status and count. These findings underline the importance of opportunistic quantitative osteoporosis screening in clinical routine MDCT data.


Subject(s)
Osteoporotic Fractures , Spinal Fractures , Male , Humans , Female , Middle Aged , Bone Density/physiology , Spinal Fractures/diagnostic imaging , Spinal Fractures/epidemiology , Retrospective Studies , Osteoporotic Fractures/diagnostic imaging , Osteoporotic Fractures/epidemiology , Osteoporotic Fractures/etiology , Bayes Theorem , Tomography, X-Ray Computed/methods , Prevalence
17.
Front Endocrinol (Lausanne) ; 14: 1222041, 2023.
Article in English | MEDLINE | ID: mdl-37576975

ABSTRACT

Objectives: Opportunistic quantitative computed tomography (oQCT) derived from non-dedicated routine CT has demonstrated high accuracy in diagnosing osteoporosis and predicting incident vertebral fractures (VFs). We aimed to investigate the cost-effectiveness of oQCT screening compared to dual-energy X-ray absorptiometry (DXA) as the standard of care for osteoporosis screening. Methods: Three screening strategies ("no osteoporosis screening", "oQCT screening", and "DXA screening") after routine CT were simulated in a state-transition model for hypothetical cohorts of 1,000 patients (women and men aged 65 years) over a follow-up period of 5 years (base case). The primary outcomes were the cumulative costs and the quality-adjusted life years (QALYs) estimated from a U.S. health care perspective for the year 2022. Cost-effectiveness was assessed based on a willingness-to-pay (WTP) threshold of $70,249 per QALY. The secondary outcome was the number of prevented VFs. Deterministic and probabilistic sensitivity analyses were conducted to test the models' robustness. Results: Compared to DXA screening, oQCT screening increased QALYs in both sexes (additional 2.40 per 1,000 women and 1.44 per 1,000 men) and resulted in total costs of $3,199,016 and $950,359 vs. $3,262,934 and $933,077 for women and men, respectively. As a secondary outcome, oQCT screening prevented 2.6 and 2.0 additional VFs per 1,000 women and men, respectively. In the probabilistic sensitivity analysis, oQCT screening remained cost-effective in 88.3% (women) and 90.0% (men) of iterations. Conclusion: oQCT screening is a cost-effective ancillary approach for osteoporosis screening and has the potential to prevent a substantial number of VFs if considered in daily clinical practice.


Subject(s)
Osteoporosis , Spinal Fractures , Male , Humans , Female , Cost-Benefit Analysis , Bone Density , Osteoporosis/diagnostic imaging , Osteoporosis/epidemiology , Mass Screening/methods , Spinal Fractures/diagnostic imaging , Spinal Fractures/epidemiology
18.
Trends Parasitol ; 39(9): 732-738, 2023 09.
Article in English | MEDLINE | ID: mdl-37438213

ABSTRACT

Plant parasites take advantage of host developmental plasticity to elicit profound developmental and physiological changes. In the case of plant-parasitic nematodes (PPNs), these changes can result in the development of new plant organs. Despite the importance of the development- and physiology-altering abilities of these parasites in pathology, research has historically focused on their abilities to suppress immunity. We argue that, given the dramatic changes involved in feeding site establishment, it is entirely possible that development- and physiology-altering abilities of PPNs may, in fact, dominate effector repertoires - highlighting the need for novel high-throughput screens for development- and physiology-altering 'tools'. Uncovering this portion of the nematode 'toolbox' can enable biotechnology, enhance crop protection, and shed light on fundamental host biology itself.


Subject(s)
Nematoda , Parasites , Animals , Host-Parasite Interactions/physiology , Nematoda/physiology , Plants/parasitology
19.
J Headache Pain ; 24(1): 84, 2023 Jul 12.
Article in English | MEDLINE | ID: mdl-37438700

ABSTRACT

BACKGROUND: Tension-type headache (TTH) is the most prevalent primary headache disorder. Neck pain is commonly associated with primary headaches and the trigemino-cervical complex (TCC) refers to the convergence of trigeminal and cervical afferents onto neurons of the brainstem, thus conceptualizes the emergence of headache in relation to neck pain. However, no objective biomarkers exist for the myofascial involvement in primary headaches. This study aimed to investigate the involvement of the trapezius muscles in primary headache disorders by quantitative magnetic resonance imaging (MRI), and to explore associations between muscle T2 values and headache frequency and neck pain. METHODS: This cohort study prospectively enrolled fifty participants (41 females, age range 20-31 years): 16 subjects with TTH only (TTH-), 12 with mixed-type TTH plus migraine (TTH+), and 22 healthy controls (HC). The participants completed fat-suppressed T2-prepared three-dimensional turbo spin-echo MRI, a headache diary (over 30 days prior to MRI), manual palpation (two weeks before MRI), and evaluation of neck pain (on the day of MRI). The bilateral trapezius muscles were manually segmented, followed by muscle T2 extraction. Associations between muscle T2 and the presence of neck pain as well as the number of days with headache (considering the 30 days prior to imaging using the headache calendar) were analyzed using regression models (adjusting for age, sex, and body mass index). RESULTS: The TTH+ group demonstrated the highest muscle T2 values (right side: 31.4 ± 1.2 ms, left side: 31.4 ± 0.8 ms) as compared to the TTH- group or HC group (p < 0.001). Muscle T2 was significantly associated with the number of headache days (ß-coefficient: 2.04, p = 0.04) and the presence of neck pain (odds ratio: 2.26, p = 0.04). With muscle T2 as the predictor, the area under the curve for differentiating between HC and the TTH+ group was 0.82. CONCLUSIONS: Increased T2 of trapezius muscles may represent an objective imaging biomarker for myofascial involvement in primary headache disorders, which could help to improve patient phenotyping and therapy evaluation. Pathophysiologically, the increased muscle T2 values could be interpreted as a surrogate of neurogenic inflammation and peripheral sensitization within myofascial tissues.


Subject(s)
Superficial Back Muscles , Tension-Type Headache , Female , Young Adult , Humans , Adult , Tension-Type Headache/diagnostic imaging , Neck Pain/diagnostic imaging , Cohort Studies , Superficial Back Muscles/diagnostic imaging , Headache
20.
Elife ; 122023 07 25.
Article in English | MEDLINE | ID: mdl-37489742

ABSTRACT

The current pace of crop plant optimization is insufficient to meet future demands and there is an urgent need for novel breeding strategies. It was previously shown that plants tolerate the generation of triparental polyspermy-derived plants and that polyspermy can bypass hybridization barriers. Polyspermy thus has the potential to harness previously incompatible climate-adapted wild varieties for plant breeding. However, factors that influence polyspermy frequencies were not previously known. The endopeptidases ECS1 and ECS2 have been reported to prevent the attraction of supernumerary pollen tubes by cleaving the pollen tube attractant LURE1. Here, we show that these genes have an earlier function that is manifested by incomplete double fertilization in plants defective for both genes. In addition to supernumerary pollen tube attraction, ecs1 ecs2 mutants exhibit a delay in synergid disintegration, are susceptible to heterofertilization, and segregate haploid plants that lack a paternal genome contribution. Our results thus uncover ECS1 and ECS2 as the first female factors triggering the induction of maternal haploids. Capitalizing on a high-throughput polyspermy assay, we in addition show that the double mutant exhibits an increase in polyspermy frequencies. As both haploid induction and polyspermy are valuable breeding aims, our results open new avenues for accelerated generation of climate-adapted cultivars.


Subject(s)
Fertilization , Plant Breeding , Haploidy , Pollen Tube/genetics
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