Abstract
We studied the light yield of a pure polystyrene slide
coated with wavelength-shifter molecules, coupled to a
photomultiplier, using
β
-
particles from a
90
Sr
source, as a possible ...easy-to-build, low-cost plastic scintillator
detector. Comparison measurements were performed with an uncoated
polystyrene slide as well as with uncoated and coated PMMA slides,
the latter which can only produce Cherenkov light when being
traversed by charged particles. The results with the single (double)
coated polystyrene slides show about 4.9 (6.3) times higher detected
photon yield compared to the uncoated slide. For comparison, the
light yield of a polystyrene-based extruded plastic scintillator
material doped with PTP and POPOP was measured as well. The
absolute detected light yield motivates future studies for
developing easy-to-build, low-cost polystyrene-based plastic
scintillator detectors.
Using a 4-hydroxytamoxifen (4OHT)-inducible, conditional Sos1-null mutation, we analyzed wild-type (WT), single Sos1-KO, Sos2-KO and double Sos1/2 KO primary mouse embryonic fibroblasts (MEF) with an ...aim at evaluating the functional specificity or redundancy of the Sos1 and Sos2 alleles at the cellular level. The 4OHT-induced Sos1-KO and Sos1/2-DKO MEFs exhibited distinct flat morphology, enlarged cell perimeter and altered cytoskeletal organization that were not observed in the WT and Sos2-KO counterparts. The Sos1-KO and Sos1/2-DKO MEFs also displayed significant accumulation, in comparison with WT and Sos2-KO MEFs, of cytoplasmic vesicular bodies identified as autophagosomes containing degraded mitochondria by means of electron microscopy and specific markers. Cellular proliferation and migration were impaired in Sos1-KO and Sos1/2-DKO MEFs in comparison with WT and Sos2-KO MEFs, whereas cell adhesion was only impaired upon depletion of both Sos isoforms. RasGTP formation was practically absent in Sos1/2-DKO MEFs as compared with the other genotypes and extracellular signal-regulated kinase phosphorylation showed only significant reduction after combined Sos1/2 depletion. Consistent with a mitophagic phenotype, in vivo labeling with specific fluorophores uncovered increased levels of oxidative stress (elevated intracellular reactive oxygen species and mitochondrial superoxide and loss of mitochondrial membrane potential) in the Sos1-KO and the Sos1/2-DKO cells as compared with Sos2-KO and WT MEFs. Interestingly, treatment of the MEF cultures with antioxidants corrected the altered phenotypes of Sos1-KO and Sos1/2-DKO MEFs by restoring their altered perimeter size and proliferative rate to levels similar to those of WT and Sos2-KO MEFs. Our data uncover a direct mechanistic link between Sos1 and control of intracellular oxidative stress, and demonstrate functional prevalence of Sos1 over Sos2 with regards to cellular proliferation and viability.
Study of retinal structure based on optical coherence tomography (OCT) data can facilitate early diagnosis of relapsing-remitting multiple sclerosis (RRMS). Although artificial intelligence can ...provide highly reliable diagnoses, the results obtained must be explainable.
The study included 79 recently diagnosed RRMS patients and 69 age matched healthy control subjects. Thickness (Avg) and inter-eye difference (Diff) features are obtained in 4 retinal layers using the posterior pole protocol. Each layer is divided into six analysis zones. The Support Vector Machine plus Recursive Feature Elimination with Leave-One-Out Cross Validation (SVM-RFE-LOOCV) approach is used to find the subset of features that reduces dimensionality and optimises the performance of the classifier.
SVM-RFE-LOOCV was used to identify OCT features with greatest capacity for early diagnosis, determining the area of the papillomacular bundle to be the most influential. A correlation was observed between loss of layer thickness and increase in functional disability. There was also greater functional deterioration in patients with greater asymmetry between left and right eyes. The classifier based on the top-ranked features obtained sensitivity = 0.86 and specificity = 0.90.
There was consistency between the features identified as relevant by the SVM-RFE-LOOCV approach and the retinotopic distribution of the retinal nerve fibres and the optic nerve head. This simple method contributes to implementation of an assisted diagnosis system and its accuracy exceeds that achieved with magnetic resonance imaging of the central nervous system, the current gold standard. This paper provides novel insights into RRMS affectation of the neuroretina.
IntroductionTo ascertain specific functional role(s) of the Sos1 and Sos2 Ras-GEF activators we investigated phenotypic effects of single or combined disruption of Sos1 and/or Sos2 in adult mice by ...using a tamoxifen-inducible Sos1-KO system. Upon TAM induction, the resulting Sos1/2-DKO animals die precipitously (in about 2 weeks) whereas single Sos1-KO or Sos2-KO adult mice are perfectly viable. Histological examination of DKO mice showed that the internal organs most severely affected by concomitant Sos1 and Sos2 loss include the liver and gallbladder in the gastrointestinal (GI) tract.Material and methodsTo determine cause(s) of the quick death of Sos1/2-DKO mice, we analysed blood and GI tissues from 6–8 week-old mice of 4 relevant Sos genotypes (WT, Sos1-KO, Sos2-KO and Sos1/2-DKO) similarly treated with TAM for 13 days. Different biochemical parameters were quantitated in blood serum and liver samples, and various IHC assays were also performed on different organs of the GI tract. Liver regeneration was characterised by means of partial hepatectomy studies of WT, Sos1-KO and Sos2-KO animals previously treated with TAM for 10 days.Results and discussionsCombined loss of Sos1 and Sos2 in DKO mice resulted in markedly reduced levels of total serum protein and increased serum levels of lactate dehydrogenase, creatinine kinase and other liver enzymes, suggesting the occurrence of substantial liver failure in these animals. Histological analysis of the DKO animals showed a quick overall structural degeneration of the liver accompanied by increased levels of oxidative stress in the hepatic lobules. We also observed marked distension of the gallbladder, perhaps linked to decreased CCK levels in the gut mucosa cells. The dilatation of the gallbladder together with the observed decrease of serum triglycerides and fat in all the organs analysed point to significant impairment of the lipidic metabolism in Sos1/2-DKO mice. Finally, our partial hepatectomy studies in single Sos KO mice showed that hepatic regeneration critically depends on the presence of Sos1, whereas Sos2 appears to be dispensable for this process of organ recovery after liver damage.ConclusionOur data suggest functional redundancy of Sos1 and Sos2 for overall homeostasis of GI organs, especially liver and gallbladder. Our studies also show that Sos1, but not Sos2, is the main, critical RasGEF required for liver regeneration and tissue repair upon organ injury.Supported by AECC, PI16/0213, PI19/01083, CB16/12/00352 (ISCIII) and SA043U16 (CyL-FEDER) Spain
Nephronophthisis (NPHP) is the most frequent genetic cause of chronic renal failure in children. Identification of four genes mutated in NPHP subtypes 1-4 (refs. 4-9) has linked the pathogenesis of ...NPHP to ciliary functions. Ten percent of affected individuals have retinitis pigmentosa, constituting the renal-retinal Senior-Loken syndrome (SLSN). Here we identify, by positional cloning, mutations in an evolutionarily conserved gene, IQCB1 (also called NPHP5), as the most frequent cause of SLSN. IQCB1 encodes an IQ-domain protein, nephrocystin-5. All individuals with IQCB1 mutations have retinitis pigmentosa. Hence, we examined the interaction of nephrocystin-5 with RPGR (retinitis pigmentosa GTPase regulator), which is expressed in photoreceptor cilia and associated with 10-20% of retinitis pigmentosa. We show that nephrocystin-5, RPGR and calmodulin can be coimmunoprecipitated from retinal extracts, and that these proteins localize to connecting cilia of photoreceptors and to primary cilia of renal epithelial cells. Our studies emphasize the central role of ciliary dysfunction in the pathogenesis of SLSN.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The present study is a morphological and quantitative analysis of protein kinase C-like immunoreactive (PKC-L ir) bipolar cells in the retinas of five different vertebrate species (chicken, tench, ...zebrafish, goldfish and rat). The morphology of PKC-L-ir bipolar cell axon terminals in fish differs significantly from those of chicken and rat retinas. Fish have bulky terminals whereas chicken and rat have their terminals in the form of small knob-shaped branches. In tench and goldfish, PKC-L-ir bipolar cells gradually decrease in size from the medial (i.e., in tench: mean +/- SD soma area of 30.09 +/- 5.98 microm2) to the peripheral (i.e., in tench: 19.93 +/- 1.73 microm2) retinal regions. This is not observed in chicken, rat or zebrafish where there is more homogeneity in s oma and axon terminal sizes between different retinal regions. Except in chicken, cell density increases from the central (i.e., in tench: mean +/- SD 1795.88 +/- 242.35 cells/mm2) to the peripheral (i.e., in tench: 4295.41 +/- 279.23 cells/mm2) retina. This study provides data that show relevant differences in the PKC-L-ir bipolar morphology and density among birds, fish and mammals. Moreover, these structural variations could mean not only differences in the cellular physiology, but also in the patterns of development and maintenance of the retina in each species.
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