The glymphatic pathway is a system which facilitates continuous cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange and plays a key role in removing waste products from the rodent brain. Dysfunction of the glymphatic pathway may be implicated in the pathophysiology of Alzheimer's disease. Intriguingly, the glymphatic system is most active during deep wave sleep general anesthesia. By using paramagnetic tracers administered into CSF of rodents, we previously showed the utility of MRI in characterizing a macroscopic whole brain view of glymphatic transport but we have yet to define and visualize the specific flow patterns. Here we have applied an alternative mathematical analysis approach to a dynamic time series of MRI images acquired every 4 min over ∼3 hrs in anesthetized rats, following administration of a small molecular weight paramagnetic tracer into the CSF reservoir of the cisterna magna. We use Optimal Mass Transport (OMT) to model the glymphatic flow vector field, and then analyze the flow to find the network of CSF-ISF flow channels. We use 3D visualization computational tools to visualize the OMT defined network of CSF-ISF flow channels in relation to anatomical and vascular key landmarks from the live rodent brain. The resulting OMT model of the glymphatic transport network agrees largely with the current understanding of the glymphatic transport patterns defined by dynamic contrast-enhanced MRI revealing key CSF transport pathways along the ventral surface of the brain with a trajectory towards the pineal gland, cerebellum, hypothalamus and olfactory bulb. In addition, the OMT analysis also revealed some interesting previously unnoticed behaviors regarding CSF transport involving parenchymal streamlines moving from ventral reservoirs towards the surface of the brain, olfactory bulb and large central veins.
Males of a Drosophila melanogaster isogenic line with a mutation of the major gene for radius incompletus (ri) were treated by standard light heat shock (3TC for 90 min) and by heavy heat shock (transfer of males from 37C for 2 hr to 4rC for 1 hr and back; this procedure was repeated three times). In the F1 generation of treated males mated with nontreated females of the same isogenic line, mass transpositions of copia-like mobile genetic element Dm-412 were found. The altered positions ofthe element seem nonrandom; five "hot spots" of transposition were found. Probabilities of transpositions were estimated after light heat shock and heavy heat shock and in the control sample. These probabilities were, respectively, 3.4 x 10-2, 8.7 x 10-2, and <4.1 x 10-4 transpositions per genome per occupied position per generation. Therefore, as a result of heat shock treatment, the probabilities of transpositions were two orders of magnitude greater than those of the control sample in the next generation after induction. Comparison of the results with those after stepwise temperature treatment shows that the induction depends on the intensity of the stress action (temperature treatment) rather than on the type of the stress action. (7) and HS regulation sites (8, 9). After HS treatment of flies, transcription and transposition of different MGEs seemed to be activated (9-11).From this evidence, speculations and hypotheses have been advanced about the genetic system of HS regulation in relation to heritable temperature effects in Drosophila (4, 5, 10-12). There have also been theories about the evolutionary importance of the genome system of MGE genomic patterns after environmental stress (temperature, etc.) (4,5,(10)(11)(12).However, the data are incomplete. Vasilyeva and coworkers (1-3, 13) in most of their work used heterogeneous Drosophila lines, and in situ hybridization was done many tens of generations after temperature treatment. Indeed, in some repeated experiments this interval was decreased to several generations with the same results. But the possibility of selective influence was not excluded completely. Junakovic et al. (6) found the effects in the next generation, but their restriction fragments were not compared with patterns of MGE localization in polytene chromosomes.In this paper (see also ref. 14), we present data that demonstrate multiple transpositions of copia-like MGE Dm-412 in the next generation after HS treatment. This work was done with an isogenic Drosophila line to decrease pattern variability in the control sample and after treatment. MATERIALS AND METHODSIsogenic Lines. The isogenic lines with a mutation of the major gene for ri were created by using marked balanced chromosomes (15): M5 (X chromosome), Cy/Pm (chromosome 2), D/Sb (chromosome 3). Of 20 isogenic lines, one (N 49) was used for the HS treatment, being most stable in its pattern of MGE Dm412 localization and expression of the character ri.Control Sample. Young males and virgin females were collected from mass cultures of isog...
Background: Digital breast tomosynthesis (DBT) has higher diagnostic accuracy than digital mammography, but interpretation time is substantially longer. Artificial intelligence (AI) could improve reading efficiency. Purpose:To evaluate the use of AI to reduce workload by filtering out normal DBT screens. Materials and Methods:The retrospective study included 13 306 DBT examinations from 9919 women performed between June 2013 and November 2018 from two health care networks. The cohort was split into training, validation, and test sets (3948, 1661, and 4310 women, respectively). A workflow was simulated in which the AI model classified cancer-free examinations that could be dismissed from the screening worklist and used the original radiologists' interpretations on the rest of the worklist examinations. The AI system was also evaluated with a reader study of five breast radiologists reading the DBT mammograms of 205 women. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and recall rate were evaluated in both studies. Statistics were computed across 10 000 bootstrap samples to assess 95% CIs, noninferiority, and superiority tests. Results:The model was tested on 4310 screened women (mean age, 60 years 6 11 [standard deviation]; 5182 DBT examinations). Compared with the radiologists' performance (417 of 459 detected cancers [90.8%], 477 recalls in 5182 examinations [9.2%]), the use of AI to automatically filter out cases would result in 39.6% less workload, noninferior sensitivity (413 of 459 detected cancers; 90.0%; P = .002), and 25% lower recall rate (358 recalls in 5182 examinations; 6.9%; P = .002). In the reader study, AUC was higher in the standalone AI compared with the mean reader (0.84 vs 0.81; P = .002). Conclusion:The artificial intelligence model was able to identify normal digital breast tomosynthesis screening examinations, which decreased the number of examinations that required radiologist interpretation in a simulated clinical workflow.Published under a CC BY 4.0 license.
The phenomenon of transposition induction by heavy heat shock (HHS) was studied. Males of a Drosophila isogenic line with a mutation in the major gene radius incompletus (ri) were treated by HHS (37 degrees C for 1 h followed by 4 degrees C for 1 h, with the cycle repeated three times) and crossed to untreated females of the same line. The males were crossed 5 d after heat shock, and also 9 d after HHS. Many transpositions were seen in the F1 larvae by in situ hybridization. The rate of induced transposition was at least 2 orders of magnitude greater than that of the control sample, and was estimated to be 0.11 events per transposable element copy per sperm. Two 'hot' subdivisions for transpositions, induced probably during the post-meiotic stage of spermiogenesis, were found: 43B and 97DE. Three-quarters of all transpositions were localized in these positions. In other sites the rates of induced transpositions were (1.3-3.2) x 10(-2) events per occupied segment per sperm, 1 order of magnitude greater than those of the control.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.