Training radiology residents to evaluate deep myometrial invasion in endometrial cancer patients on MRI: A learning curve study.

PURPOSE: To evaluate the impact of a four-month training program on radiology residents' diagnostic accuracy in assessing deep myometrial invasion (DMI) in endometrial cancer (EC) using MRI. METHOD: Three radiology residents with limited EC MRI experience participated in the training program, which included conventional didactic sessions, case-centric workshops, and interactive classes. Utilizing a training dataset of 120 EC MRI scans, trainees independently assessed subsets of cases over five reading sessions. Each subset consisted of 30 scans, the first and the last with the same cases, for a total of 150 reads. Diagnostic accuracy metrics, assessment time (rounded to the nearest minute), and confidence levels (using a 5-point Likert scale) were recorded. The learning curve was obtained plotting the diagnostic accuracy of the three trainees and the average over the subsets. Anatomopathological results served as the reference standard for DMI presence. RESULTS: The three trainees exhibited heterogeneous starting point, with a learning curve and a trend to more homogeneous performance with training. The diagnostic accuracy of the average trainee raised from 64 % (56 %-76 %) to 88 % (80 %-94 %) across the five subsets (p < 0.001). Reductions in assessment time (5.92 to 4.63 min, p < 0.018) and enhanced confidence levels (3.58 to 3.97, p = 0.12) were observed. Improvements in sensitivity, specificity, positive predictive value, and negative predictive value were noted, particularly for specificity which raised from 56 % (41 %-68 %) in the first to 86 % (74 %-94 %) in the fifth subset (p = 0.16). Although not reaching statistical significance, these advancements aligned the trainees with literature performance benchmarks. CONCLUSIONS: The structured training program significantly enhanced radiology residents' diagnostic accuracy in assessing DMI for EC on MRI, emphasizing the effectiveness of active case-based training in refining oncologic imaging skills within radiology residency curricula.

ERO1α primes the ryanodine receptor to respond to arsenite with concentration dependent Ca2+ release sequentially triggering two different mechanisms of ROS formation.

A 6 h exposure of U937 cells to 2.5 µM arsenite stimulates low Ca2+ release from the inositol 1, 4, 5-triphosphate receptor (IP3R), causing a cascade of causally connected events, i.e., endoplasmic reticulum oxidoreductin-1α (ERO1α) expression, activation of the ryanodine receptor (RyR), mitochondrial Ca2+ accumulation, mitochondrial superoxide formation and further ERO1α expression. At greater arsenite concentrations, the release of the cation from the IP3R and the ensuing ERO1α expression remained unchanged but were nevertheless critical to sequentially promote concentration-dependent increases in Ca2+ release from the RyR, NADPH oxidase activation and a third mechanism of ERO1α expression which, in analogy to the one driven by mitochondrial superoxide, was also mediated by reactive oxygen species (ROS) and devoid of effects on Ca2+ homeostasis. Thus, concentration-independent stimulation of Ca2+ release from the IP3R is of pivotal importance for the effects of arsenite on Ca2+ homeostasis. It stimulates the expression of a fraction of ERO1α that primes the RyR to respond to the metalloid with concentration-dependent Ca2+-release, triggering the formation of superoxide in the mitochondrial respiratory chain and via NADPH oxidase activation. The resulting dose-dependent ROS formation was associated with a progressive increase in ERO1α expression, which however failed to affect Ca2+ homeostasis, thereby suggesting that ROS, unlike IP3R-dependent Ca2+ release, promote ERO1α expression in sites distal from the RyR.

Arsenite enhances ERO1α expression via ryanodine receptor dependent and independent mechanisms.

Arsenite is a potent carcinogen and toxic compound inducing an array of deleterious effects via different mechanisms, which include the Ca2+-dependent formation of reactive oxygen species. The mechanism whereby the metalloid affects Ca2+ homeostasis involves an initial stimulation of the inositol 1, 4, 5-triphosphate receptor, an event associated with an endoplasmic reticulum (ER) stress leading to increased ERO1α expression, and ERO1α dependent activation of the ryanodine receptor (RyR). Ca2+ release from the RyR is then critically connected with the mitochondrial accumulation of Ca2+. We now report that the resulting formation of mitochondrial superoxide triggers a second mechanism of ER stress dependent ERO1α expression, which however fails to impact on Ca2+ release from the RyR or, more generally, on Ca2+ homeostasis. Our results therefore demonstrate that arsenite stimulates two different and sequential mechanisms leading to increased ERO1α expression with different functions, possibly due to their different subcellular compartmentalization.

Inhibition of activity/expression, or genetic deletion, of ERO1α blunts arsenite geno- and cyto-toxicity.

Our recent studies suggest that arsenite stimulates the crosstalk between the inositol 1, 4, 5-triphosphate receptor (IP3R) and the ryanodine receptor (RyR) via a mechanism dependent on endoplasmic reticulum (ER) oxidoreductin1α (ERO1α) up-regulation. Under these conditions, the fraction of Ca2+ released by the RyR via an ERO1α-dependent mechanism was promptly cleared by the mitochondria and critically mediated O2-. formation, responsible for the triggering of time-dependent events associated with strand scission of genomic DNA and delayed mitochondrial apoptosis. We herein report that, in differentiated C2C12 cells, this sequence of events can be intercepted by genetic deletion of ERO1α as well as by EN460, an inhibitor of ERO1α activity. Similar results were obtained for the early effects mediated by arsenite in proliferating U937 cells, in which however the long-term studies were hampered by the intrinsic toxicity of the inhibitor. It was then interesting to observe that ISRIB, an inhibitor of p-eIF2 alpha, was in both cell types devoid of intrinsic toxicity and able to suppress ERO1α expression and the resulting downstream effects leading to arsenite geno- and cyto-toxicity. We therefore conclude that pharmacological inhibition of ERO1α activity, or expression, effectively counteracts the deleterious effects induced by the metalloid via a mechanism associated with prevention of mitochondrial O2-. formation.

Patterns of Plumericin Concentration in Leaves of Himatanthus tarapotensis (Apocynaceae) and Its Interactions with Herbivory in the Peruvian Amazon.

We explored the concentration patterns of the bioactive metabolite plumericin produced by Himatanthus tarapotensis (Apocynaceae) under different edaphic conditions and variations in rainfall intensity, as well as its potential role in the chemical defense against insect herbivores. Values of plumericin concentration from leaves were obtained by High-Performance Liquid Chromatography, and evaluated as a function of differences in soil types, variation of precipitation, and variation of the abundance of insect herbivores, using first a Repeated Measures Correlation (rmcorr) and then a Generalized Linear Mixed Model (GLMM) analysis. Plumericin concentration is highly variable among plants, but with a significantly higher concentration in plants growing on clay soil compared to that of the white-sand soil habitat (p < 0.001). Plumericin concentration is not affected by precipitation. The caterpillar of Isognathus leachii (Lepidoptera: Sphingidae) is the most conspicuous herbivore of H. tarapotensis, and its presence is continuous but not related to plumericin concentration, probably because of its capacity to elude the chemical defense of this plant. Nevertheless, our multivariate model revealed that plumericin concentration is related to the abundance of Hymenoptera (Formicidae), and this relationship is significantly influenced by the soil parameters of carbon percentage, clay percentage, and phosphorous percentage (p < 0.001). Plumericin is a mediating agent in the interaction between H. tarapotensis and its natural environment. Variation in plumericin concentration would be induced by the abundance of Hymenoptera (Formicidae), probably as a chemical response against these insects, and by differences in soil nutrient availability.

Crosstalk between ERO1α and ryanodine receptor in arsenite-dependent mitochondrial ROS formation.

Arsenite, a well-established human carcinogen and toxic compound, promotes the formation of mitochondrial superoxide (mitoO2-) via a Ca2+-dependent mechanism, in which an initial stimulation of the inositol 1, 4, 5-trisphosphate receptor (IP3R) is followed by the activation of the ryanodine receptor (RyR), critical for providing Ca2+ to the mitochondria. We now report that, under the same conditions, arsenite triggers endoplasmic reticulum (ER) stress and a threefold increase in ER oxidoreductin 1α (ERO1 α) levels in proliferating U937 cells. EN460, an inhibitor of ERO1 α, recapitulated all the effects associated with RyR inhibition or downregulation, including prevention of RyR-induced Ca2+ accumulation in mitochondria and the resulting O2-. formation. Quantitatively similar results were obtained in inhibitor studies performed in terminally differentiated wild type C2C12 cells. Moreover, ERO1 α knockout C2C12 myotubes responded to arsenite as their wild type counterpart supplemented with EN460. As a final note, arsenite enhanced the expression of ERO1 α via a mechanism mediated by Ca2+ release from both the IP3R and RyR. We therefore conclude that arsenite activates a positive feedback amplification cycle between Ca2+ levels and ERO1 α in the ER, by which IP3R-dependent Ca2+ induces ERO1 α and ERO1 α promotes Ca2+ release via RyR, thereby amplifying the initial Ca2+ load and causing the mitochondrial accumulation of the cation, critical for mitoO2- formation.

Functional organization of the endoplasmic reticulum dictates the susceptibility of target cells to arsenite-induced mitochondrial superoxide formation, mitochondrial dysfunction and apoptosis.

Arsenite induces many critical effects associated with the formation of reactive oxygen species (ROS) through different mechanisms. We focused on Ca2+-dependent mitochondrial superoxide (mitoO2-.) formation and addressed questions on the effects of low concentrations of arsenite on the mobilization of the cation from the endoplasmic reticulum and the resulting mitochondrial accumulation. Using various differentiated and undifferentiated cell types uniquely expressing the inositol-1, 4, 5-triphosphate receptor (IP3R), or both the IP3R and the ryanodine receptor (RyR), we determined that expression of this second Ca2+ channel is an absolute requirement for mitoO2-. formation and for the ensuing mitochondrial dysfunction and downstream apoptosis. In arsenite-treated cells, RyR was recruited after IP3R stimulation and agonist studies provided an indirect indication for a close apposition between RyR and mitochondria. It was also interesting to observe that arsenite fails to promote mitochondrial Ca2+ accumulation, mitoO2-. formation and mitochondrial toxicity in RyR-devoid cells, in which the IP3R is in close contact with the mitochondria. We therefore conclude that low dose arsenite-induced mitoO2- formation, and the resulting mitochondrial dysfunction and toxicity, are prerequisite of cell types expressing the RyR in close apposition with mitochondria.

Electronic detection of Drechslera sp. fungi in charentais melon ( Cucumis melo Naudin) using carbon-nanostructure-based sensors.

The development of chemical sensor technology in recent years has stimulated an interest regarding the use of characteristic volatiles and odors as a rapid and early indication of deterioration in fruit quality. The fungal infestation by Drechslera sp. in melons is a severe problem, and we demonstrate that electronic sensors based on carbon nanostructures are able to detect the presence of these fungi in melon. The responses of sensor conductance G and capacitance C at 27 kHz were measured and used to calculate their ΔG and ΔC variation over the full melon ripening process under shelf conditions with proliferation of Drechslera sp. fungi. The sensor response showed that these fungi can be electronically identified in charentais melon, constituting an effective and cheap test procedure to differentiate between infected and uninfected melon.