A large number of correlative studies have established that the activation of the unfolded protein response (UPR) alters the cell's sensitivity to chemotherapeutic agents. Although the induction of ...the glucose-regulated proteins (GRPs) is commonly used as an indicator for the UPR, the direct role of the GRPs in conferring resistance to DNA damaging agents has not been proven. We report here that without the use of endoplasmic reticulum (ER) stress inducers, specific overexpression of GRP78 results in reduced apoptosis and higher colony survival when challenged with topoisomerase II inhibitors, etoposide and doxorubicin, and topoisomerase I inhibitor, camptothecin. While investigating the mechanism for the GRP78 protective effect against etoposide-induced cell death, we discovered that in contrast to the UPR, GRP78 overexpression does not result in G1 arrest or depletion of topoisomerase II. Caspase-7, an executor caspase that is associated with the ER, is activated by etoposide. We show here that specific expression of GRP78 blocks caspase-7 activation by etoposide both in vivo and in vitro, and this effect can be reversed by addition of dATP in a cell-free system. Recently, it was reported that ectopically expressed GRP78 and caspases-7 and -12 form a complex, thus coupling ER stress to the cell death program. However, the mechanism of how GRP78, a presumably ER lumen protein, can regulate cytosolic effectors of apoptosis is not known. Here we provide evidence that a subpopulation of GRP78 can exist as an ER transmembrane protein, as well as co-localize with caspase-7, as confirmed by fluorescence microscopy. Co-immunoprecipitation studies further reveal endogenous GRP78 constitutively associates with procaspase-7 but not with procaspase-3. Lastly, a GRP78 mutant deleted of its ATP binding domain fails to bind procaspase-7 and loses its protective effect against etoposide-induced apoptosis.
•Robotic SEEG reduces mean operative time compared to frameless stereotaxy.•Less hospital costs are incurred with robotic SEEG.•Robotic and navigated SEEG demonstrated equivalent safety profile.
...Stereoelectroencephalography (SEEG) has experienced a recent growth in adoption for epileptogenic zone (EZ) localization. Advances in robotics have the potential to improve the efficiency and safety of this intracranial seizure monitoring method. We present our institutional experience employing robot-assisted SEEG and compare its operative efficiency, seizure reduction outcomes, and direct hospital costs with SEEG performed without robotic assistance using navigated stereotaxy.
We retrospectively identified 50 consecutive adult SEEG cases at our institution in this IRB-approved study, of which 25 were navigated with image guidance (hereafter referred to as “navigated”) (02/2014-10/2016) and 25 were robot-assisted (09/2016-12/2017). A thorough review of medical/surgical history and operative records with imaging and trajectory plans was done for each patient. Direct inpatient costs related to each technique were compared.
Most common seizure etiologies for patients undergoing navigated and robot-assisted SEEG included non-lesional and benign temporal lesions. Despite having a higher mean number of leads-per-patient (10.2 ± 3.5 versus 7.2 ± 2.6, P = 0.002), robot-assisted cases had a significantly shorter mean operative time than navigated cases (125.5±48.5 versus 173.4±84.3 min, P = 0.02). Comparison of robot-assisted cases over the study interval revealed no significant difference in mean operative time (136.4±51.4 min for the first ten cases versus 109.9±75.8 min for the last ten cases, P = 0.25) and estimated operative time-per-lead (13.4±6.0 min for the first ten cases versus 12.9±7.7 min for the last ten cases, P = 0.86). The mean depth, radial, target, and entry point errors for robot-assisted cases were 2.12±1.89, 1.66±1.58, 3.05±2.02 mm, and 1.39 ± 0.75 mm, respectively. The two techniques resulted in equivalent EZ localization rate (navigated 88 %, robot-assisted 96 %, P = 0.30). Common types of epilepsy surgery performed consisted of implantation of responsive neurostimulation (RNS) device (56 %), resection (19.1 %), and laser ablation (23.8 %) for navigated SEEG. For robot-assisted SEEG, either RNS implantation (68.2 %) or laser ablation (22.7 %) were performed or offered. A majority of navigated and robot-assisted patients who underwent epilepsy surgery achieved either Engel Class I (navigated 36.8 %, robot-assisted 31.6 %) or II (navigated 36.8 %, robot-assisted 15.8 %) outcome with no significant difference between the groups (P = 0.14). Direct hospital cost for robot-assisted SEEG was 10 % higher than non-robotic cases.
This single-institutional study suggests that robotic assistance can enhance efficiency of SEEG without compromising safety or precision when compared to image guidance only. Adoption of this technique with uniform safety and efficacy over a short period of time is feasible with favorable epilepsy outcomes.
Serial studies have demonstrated that induction therapy with FLAM flavopiridol (alvocidib) 50 mg/m(2) days 1-3, cytarabine 667 mg/m(2)/day continuous infusion days 6-8, and mitoxantrone (FLAM) 40 ...mg/m(2) day 9 yields complete remission rates of nearly 70% in newly diagnosed poor-risk acute myeloid leukemia. Between May 2011-July 2013, 165 newly diagnosed acute myeloid leukemia patients (age 18-70 years) with intermediate/adverse-risk cytogenetics were randomized 2:1 to receive FLAM or 7+3 (cytarabine 100 mg/m(2)/day continuous infusion days 1-7 and daunorubicin 90 mg/m(2) days 1-3), across 10 institutions. Some patients on 7+3 with residual leukemia on day 14 received 5+2 (cytarabine 100 mg/m(2)/day continuous infusion days 1-5 and daunorubicin 45 mg/m(2) days 1-2), whereas patients on FLAM were not re-treated based on day 14 bone marrow findings. The primary objective was to compare complete remission rates between one cycle of FLAM and one cycle of 7+3. Secondary end points included safety, overall survival and event-free survival. FLAM led to higher complete remission rates than 7+3 alone (70% vs. 46%; P=0.003) without an increase in toxicity, and this improvement persisted after 7+3+/-5+2 (70% vs. 57%; P=0.08). There were no significant differences in overall survival and event-free survival in both arms but post-induction strategies were not standardized. These results substantiate the efficacy of FLAM induction in newly diagnosed AML. A phase III study is currently in development. This study is registered with clinicaltrials.gov identifier: 01349972.
Hyperhomocysteinemia is an independent risk factor for cardiovascular disease and accelerates atherosclerosis in apoE–/– mice. Despite the observations that homocysteine causes endoplasmic reticulum ...(ER) stress and programmed cell death (PCD) in cultured human vascular endothelial cells, the cellular factors responsible for this effect and their relevance to atherogenesis have not been completely elucidated. We report here that homocysteine induces the expression of T-cell death-associated gene 51 (TDAG51), a member of the pleckstrin homology-related domain family, in cultured human vascular endothelial cells. This effect was observed for other ER stress-inducing agents, including dithiothreitol and tunicamycin. TDAG51 expression was attenuated in homozygous A/A mutant eukaryotic translation initiation factor 2α mouse embryonic fibroblasts treated with homocysteine or tunicamycin, suggesting that ER stress-induced phosphorylation of eukaryotic translation initiation factor 2α is required for TDAG51 transcriptional activation. Transient overexpression of TDAG51 elicited significant changes in cell morphology, decreased cell adhesion, and promoted detachment-mediated PCD. In support of these in vitro findings, TDAG51 expression was increased and correlated with PCD in the atherosclerotic lesions from apoE–/– mice fed hyperhomocysteinemic diets, compared with mice fed a control diet. Collectively, these findings provide evidence that TDAG51 is induced by homocysteine, promotes detachment-mediated PCD, and contributes to the development of atherosclerosis observed in hyperhomocysteinemia.
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•Geographic and topological discordance from nDNA introgression and mtDNA isolation.•Isolation limited across the Gulf Coast despite ancient divergence.•Populations with ...differentiated calls appear to experience limited introgression.•Maintenance of allopatry appears more important than timing of initial divergence.
Complicated phylogenetic histories benefit from diverse sources of inference. Pseudacris crucifer (spring peeper) spans most of eastern North America and comprises six mtDNA lineages that form multiple contact zones. The putative Miocene or early Pliocene origins of the oldest lineages within Pseudacris crucifer imply sufficient time for species-level divergence. To understand why this species appears unified while congeners have radiated, we analyze and compare male advertisement calls, mitochondrial, and nuclear markers and speak to the complex processes that have potentially influenced its contemporary patterns. We find extensive geographic and topological mitonuclear discordance, with three nuclear lineages containing 6 more-structured mtDNA lineages, and nuclear introgression at some contact zones. Male advertisement call differentiation is incongruent with the genetic structure as only one lineage appears differentiated. Occupying the Interior Highlands of the central United States, this Western lineage also has the most concordant mitochondrial and nuclear geographic patterns. Based on our findings we suggest that the antiquity of common ancestors was not as important as the maintenance of allopatry in the divergence in P. crucifer genetic lineages. We use multiple lines of evidence to generate hypotheses of isolation, reticulation, and discordance within this species and to expand our understanding of the early stages of speciation.
Although most temperate forests are actively managed for timber production, few data exist regarding the long-term effects of forest management on understory plant communities. We investigated the ...responses of understory communities to a factorial combination of silvicultural-thinning and nutrient-addition treatments maintained for 12-16 yr in a set of 21-27 yr old Douglas-fir (Pseudotsuga menziesii) plantations. The four thinning levels span those used operationally (final stem densities of 494-1680 trees/ha); the two fertilization levels included a control and N addition in the form of urea at ∼60 kg N·ha-1·yr-1, about twice the dosage used operationally. Understory vegetation cover showed significant effects of thinning, with the highest thinning level resulting in the highest observed cover values. However, in some cases low levels of thinning resulted in a reduction in understory cover compared to unthinned controls. Understory vegetation declined dramatically in response to urea fertilization, with up to a 10-fold drop in herb-layer cover in unthinned stands. Species richness showed a simpler response to treatments, increasing in response to thinning, but decreasing in response to fertilization. Examination of species-area relationships indicated that effects of thinning and fertilization on species richness were similar across the range of spatial scales examined. Tree canopy cover, assessed by means of hemispherical photograph analysis, increased with fertilization, and estimated understory light levels decreased with fertilization, but neither showed a significant response to thinning at the time of measurement (12-16 yr after tree removal). Thus, treatment effects on understory cover and species richness were not a simple function of canopy cover or estimated light availability. Rather, there was a weak positive relationship between estimated understory light flux and vascular plant cover and diversity in nonfertilized plots, and no such relationship in fertilized plots. The lack of correspondence between treatment effects on canopy cover and understory vegetation maybe due to time lags in understory response to changes in canopy cover or to treatment effects not mediated by light availability, such as physical disturbance during thinning operations and toxicity responses following application of urea fertilizer. Species-specific responses to treatments were in part predictable as a function of plant life-form and edaphic association: species affinity for high soil moisture was the best predictor of fertilization responses, while life-form was the best predictor of thinning responses, with ferns and graminoids showing the largest positive responses to thinning. The successional status and stature of understory plant species were not significantly related to treatment responses. In sum, our results indicate that silvicultural thinning and fertilization can have large effects on understory plant diversity and community composition. However, such effects were not a simple function of understory light levels, and conventional "functional types" were of only limited value in predicting species-specific responses to silvicultural treatments.
Over the last two decades many secrets of the age-related human neural proteinopathies have been revealed. A common feature of these diseases is abnormal, and possibly pathogenic, aggregation of ...specific proteins in the effected tissue often resulting from inherent or decreased structural stability. An archetype example of this is superoxide dismutase-1, the first genetic factor to be linked with amyotrophic lateral sclerosis (ALS). Mutant or posttranslationally modified TAR DNA binding protein-32 (TDP-43) is also strongly associated with ALS and an increasingly large number of other neurodegenerative diseases, including frontotemporal lobar degeneration (FTLD). Cytoplasmic mislocalization and elevated half-life is a characteristic of mutant TDP-43. Furthermore, patient age at the onset of disease symptoms shows a good inverse correlation with mutant TDP-43 half-life. Here we show that ALS and FTLD-associated TDP-43 mutations in the central nucleic acid binding domains lead to elevated half-life and this is commensurate with increased thermal stability and inhibition of aggregation. It is achieved without impact on secondary, tertiary, or quaternary structure. We propose that tighter structural cohesion contributes to reduced protein turnover, increasingly abnormal proteostasis and, ultimately, faster onset of disease symptoms. These results contrast our perception of neurodegenerative diseases as misfolded proteinopathies and delineate a novel path from the molecular characteristics of mutant TDP-43 to aberratn cellular effects and patient phenotype.
► On-site transient analysis of concrete structures for corrosion assessment. ► ICCP system turned off to investigate its long-term secondary protective effects. ► The complex analysis can be ...simplified and undertaken with common spreadsheet packages. ► Passive steel shows a long potential decay back to its rest potential after a short perturbation. ► Transient analysis may provide more accurate information than polarisation resistance.
A range of methods exist to assess the condition of steel reinforcement in concrete. The analysis of the transient response to a small perturbation has been employed successfully in laboratories to assess corrosion. This work examines a simplified method for the application of transient analysis to in situ reinforced concrete structures. The complex analysis has been simplified and undertaken with the use of common spreadsheet packages. The results illustrate that transient response analysis is a viable technique for use on site and appears to provide a more accurate representation of steel corrosion current densities at very low values than polarisation resistance.
River deltas grow through repeated lobe‐scale avulsions, which often occur at a location that correlates with the backwater lengthscale. Competing hypotheses attribute the avulsion node origin to ...either the morphodynamic feedbacks caused by natural flood discharge variability (backwater hypothesis) or to the prograding delta lobe geometry (geometric hypothesis). Here, using theory, historical flood records, and remotely sensed elevation data, we analyzed five lobe‐scale delta avulsions in Madagascar, captured by Landsat imagery. Avulsion lengths were 5–55 km, distances significantly longer than the backwater lengthscale and inconsistent with the geometric hypothesis. We show that the steep, silt‐bedded rivers of Madagascar have flood‐induced bed scour, driven by backwater hydrodynamics, that propagates farther upstream than the backwater lengthscale. The avulsion lengths are 3.1 ± 1.5 times the predicted flood scour lengths, similar to low‐gradient deltas, and consistent with backwater hypothesis. Results demonstrate that erosion initiated by nonuniform flows in the backwater zone is a primary control on delta avulsion locations.
Plain Language Summary
River deltas grow through abrupt channel shifts, called avulsions, which pose a threat to life and property, but we do not understand why avulsions occur where they do. One hypothesis is that flood discharge variability creates a preferential zone of sediment accumulation within the so‐called backwater zone of coastal rivers, which becomes the locus of avulsion. The rationale is that the flow acceleration and deceleration within the backwater zone during different sized floods creates nonoverlapping patterns of erosion and deposition resulting in a peak in sediment accumulation. If this hypothesis is correct, then avulsion sites should be farther upstream, relative to the backwater lengthscale, in steep rivers with fine‐grained sediment beds that have more significant bed scour during large floods. By analyzing historical avulsions on Madagascar, we found that avulsions occurred far upstream due to the large floods and fine‐grained sediment, in support of the flood discharge variability hypothesis. Our work highlights that changes in flood regime and sediment grain size of coastal rivers due to land use and climate changes can influence avulsion location.
Key Points
Using Landsat imagery spanning 1978 to 2019 CE, we identified two lobe‐scale fan and five delta avulsions on the western coast of Madascagar
Unlike low‐gradient rivers, delta avulsion lengths in steep, silt‐bedded rivers of Madagascar are much longer than the backwater lengthscale
Avulsion sites scale with expected length of the flood‐induced scour zone, bolstering the backwater hypothesis for avulsions
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