Super-resolution imaging and estimation of protein copy numbers at single synapses with DNA-PAINT

In the brain, the strength of each individual synapse is defined by the complement of proteins present or the "local proteome." Activity-dependent changes in synaptic strength are the result of changes in this local proteome and posttranslational protein modifications. Although most synaptic proteins have been identified, we still know little about protein copy numbers in individual synapses and variations between synapses. We use DNA-point accumulation for imaging in nanoscale topography as a single-molecule super-resolution imaging technique to visualize and quantify protein copy numbers in single synapses. The imaging technique provides near-molecular spatial resolution, is unaffected by photobleaching, enables imaging of large field of views, and provides quantitative molecular information. We demonstrate these benefits by accessing copy numbers of surface AMPA-type receptors at single synapses of rat hippocampal neurons along dendritic segments

Febrile Convulsions as a Problem in Waiting Times

A simple hypothesis on the occurrence of febrile convulsions is posed. This is (1) that certain children are genetically predisposed, and (2) that for such children, the probability of the first attack occurring in year 1, 2, etc., is essentially constant up to the end of the period during which the attacks can take place. These assumptions lead to a probability model which agrees well with data on age at first attack in the Town of Tecumseh, Mich. It appears that susceptibility does not gradually diminish, but rather disappears abruptly. The calculation yields an estimate of the proportion of children, among those susceptible, who will have at least one attack before they exceed the age of suceptibility. Penetrance of the condition, measured in this way, is nearly complete: 93.8% will have manifested the condition by age 7. The population frequency of the susceptible type of child is found to be 3.90%. If one assumes the simple dominant mode of inheritance of Frantzen et al. to be correct, this estimate of population frequency leads to an estimate of the gene frequency. This is approximately p = 0.02. The homozygote would therefore have a frequency of 4 per 10,000. Some speculations on verifying this theory of inheritance by identifying the homozygote are given. RÉSUMÉ On Émet une hypothÈse simple sur la survenue des convulsions fÉbriles, À savoir (1) que certains enfants sont gÉnÉtiquement prÉdisposÉs et (2) que pour ces enfants la probabilitÉ d'apparition de la premiÈre crise dans la premiÈre, la seconde annÉe, etc. est essentiellement constante jusqu'À la fin de la pÉriode pendant laquelle les crises peuvent survenir. De telles suppositions conduisent ÀÉtablir un modÈle de probabilite qui concorde bien avec les donnÉes sur l'Âge de la premiÈre crise, dans la ville de Techumseh, dans le Michigan. Il en ressort que cette prÉdisposition ne diminue pas progressivement, mais au contraire, disparaÎt brusquement. Les calculs permettent d'estimer la proportion d'enfants prÉdisposÉs qui auront au moins une crise, avant d'avoir dÉpassÉ l'Âge limite de la prÉdisposition. La pÉnÉtrance de cette condition, ainsi ÉvaluÉe, est presque complÈte: 93.8% des enfants auront manifestÉ cette condition À l'Âge de 7 ans. La frÉquence des enfants prÉdisposÉs dans la population est de 3.90%. Si l'on considÈre que le mode d'hÉrÉditÉ dominante simple de Frantzen est valable, cette estimation de la frÉquence dans la population conduit À une Évaluation de la frÉquence du gÈne. Celle-ci est approximativement de p = 0.02; l'homozygote aurait done une frÉquence de 4/10.000. Les possibilitÉs de vÉrifier cette thÉorie des modalitÉs hÉrÉditaires par l'identification de l'homozygote sont discutÉes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65705/1/j.1528-1157.1972.tb05265.x.pd

Three-Dimensional Spectral-Domain Optical Coherence Tomography Data Analysis for Glaucoma Detection

Purpose: To develop a new three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) data analysis method using a machine learning technique based on variable-size super pixel segmentation that efficiently utilizes full 3D dataset to improve the discrimination between early glaucomatous and healthy eyes. Methods: 192 eyes of 96 subjects (44 healthy, 59 glaucoma suspect and 89 glaucomatous eyes) were scanned with SD-OCT. Each SD-OCT cube dataset was first converted into 2D feature map based on retinal nerve fiber layer (RNFL) segmentation and then divided into various number of super pixels. Unlike the conventional super pixel having a fixed number of points, this newly developed variable-size super pixel is defined as a cluster of homogeneous adjacent pixels with variable size, shape and number. Features of super pixel map were extracted and used as inputs to machine classifier (LogitBoost adaptive boosting) to automatically identify diseased eyes. For discriminating performance assessment, area under the curve (AUC) of the receiver operating characteristics of the machine classifier outputs were compared with the conventional circumpapillary RNFL (cpRNFL) thickness measurements. Results: The super pixel analysis showed statistically significantly higher AUC than the cpRNFL (0.855 vs. 0.707, respectively, p = 0.031, Jackknife test) when glaucoma suspects were discriminated from healthy, while no significant difference was found when confirmed glaucoma eyes were discriminated from healthy eyes. Conclusions: A novel 3D OCT analysis technique performed at least as well as the cpRNFL in glaucoma discrimination and even better at glaucoma suspect discrimination. This new method has the potential to improve early detection of glaucomatous damage. © 2013 Xu et al

The switch-like expression of heme-regulated kinase 1 mediates neuronal proteostasis following proteasome inhibition

We examined the feedback between the major protein degradation pathway, the ubiquitin-proteasome system (UPS), and protein synthesis in rat and mouse neurons. When protein degradation was inhibited, we observed a coordinate dramatic reduction in nascent protein synthesis in neuronal cell bodies and dendrites. The mechanism for translation inhibition involved the phosphorylation of eIF2alpha, surprisingly mediated by eIF2alpha kinase 1, or heme-regulated kinase inhibitor (HRI). Under basal conditions, neuronal expression of HRI is barely detectable. Following proteasome inhibition, HRI protein levels increase owing to stabilization of HRI and enhanced translation, likely via the increased availability of tRNAs for its rare codons. Once expressed, HRI is constitutively active in neurons because endogenous heme levels are so low; HRI activity results in eIF2alpha phosphorylation and the resulting inhibition of translation. These data demonstrate a novel role for neuronal HRI that senses and responds to compromised function of the proteasome to restore proteostasis

Oxytocin receptors influence the development and maintenance of social behavior in zebrafish (Danio rerio)

Zebrafish are highly social teleost fish and an excellent model to study social behavior. The neuropeptide Oxytocin is associated different social behaviors as well as disorders resulting in social impairment like autism spectrum disorder. However, how Oxytocin receptor signaling affects the development and expression kinetics of social behavior is not known. In this study we investigated the role of the two oxytocin receptors, Oxtr and Oxtrl, in the development and maintenance of social preference and shoaling behavior in 2- to 8-week-old zebrafish. Using CRISPR/Cas9 mediated oxtr and oxtrl knock-out fish, we found that the development of social preference is accelerated if one of the Oxytocin receptors is knocked-out and that the knock-out fish reach significantly higher levels of social preference. Moreover, oxtr-/- fish showed impairments in the maintenance of social preference. Social isolation prior to testing led to impaired maintenance of social preference in both wild-type and oxtr and oxtrl knock-out fish. Knocking-out either of the Oxytocin receptors also led to increased group spacing and reduced polarization in a 20-fish shoal at 8 weeks post fertilization, but not at 4. These results show that the development and maintenance of social behavior is influenced by the Oxytocin receptors and that the effects are not just pro- or antisocial, but dependent on both the age and social context of the fish

Intracameral dexamethasone reduces inflammation on the first postoperative day after cataract surgery in eyes with and without glaucoma

Purpose: To evaluate whether dexamethasone injected intracamerally at the conclusion of surgery can safely and effectively reduce postoperative inflammation and improve surgical outcomes in eyes with and without glaucoma. Methods: Retrospective chart review of 176 consecutive eyes from 146 patients receiving uncomplicated phacoemulsification (PE) (n = 118 total, 82 with glaucoma), glaucoma drainage device (GDD) (n = 35), combined PE/GDD (n = 11) and combined PE/endoscopic cyclophotocoagulation (n = 12). Ninety-one eyes from 76 patients were injected with 0.4 mg dexamethasone intracamerally at the conclusion of surgery. All eyes received standard postoperative prednisolone and ketorolac eyedrops. Outcomes were measured for four to eight weeks by subjective complaints, visual acuity (VA), slit-lamp biomicroscopy, intraocular pressure (IOP) and postoperative complications. Results: Dexamethasone significantly reduced the odds of having an increased anterior chamber (AC) cell score after PE (p = 0.0013). Mean AC cell score ± SD in nonglaucomatous eyes was 1.3 ± 0.8 in control and 0.8 ± 0.7 with dexamethasone; scores in glaucomatous eyes were 1.3 ± 0.7 in control and 0.9 ± 0.8 with dexamethasone. Treated nonglaucomatous eyes had significantly fewer subjective complaints after PE (22.2% vs 64.7% in control; p = 0.0083). Dexamethasone had no significant effects on VA, corneal changes, IOP one day and one month after surgery, or long-term complications. Conclusions: Intracameral dexamethasone given at the end of cataract surgery significantly reduces postoperative AC cells in eyes with and without glaucoma, and improves subjective reports of recovery in nonglaucomatous eyes. There were no statistically significant risks of IOP elevation or other complications in glaucomatous eyes. © 2009 Chang et al, publisher and licensee Dove Medical Press Ltd

The translatome of neuronal cell bodies, dendrites,and axons

To form synaptic connections and store information, neurons continuously remodel their proteomes. The impressive length of dendrites and axons imposes logistical challenges to maintain synaptic proteins at locations remote from the transcription source (the nucleus). The discovery of thousands of messenger RNAs (mRNAs) near synapses suggested that neurons overcome distance and gain autonomy by producing proteins locally. It is not generally known, however, if, how, and when localized mRNAs are translated into protein. To investigate the translational landscape in neuronal subregions, we performed simultaneous RNA sequencing (RNA-seq) and ribosome sequencing (Ribo-seq) from microdissected rodent brain slices to identify and quantify the transcriptome and translatome in cell bodies (somata) as well as dendrites and axons (neuropil). Thousands of transcripts were differentially translated between somatic and synaptic regions, with many scaffold and signaling molecules displaying increased translation levels in the neuropil. Most translational changes between compartments could be accounted for by differences in RNA abundance. Pervasive translational regulation was observed in both somata and neuropil influenced by specific mRNA features (e.g., untranslated region [UTR] length, RNA-binding protein [RBP] motifs, and upstream open reading frames [uORFs]). For over 800 mRNAs, the dominant source of translation was the neuropil. We constructed a searchable and interactive database for exploring mRNA transcripts and their translation levels in the somata and neuropil [MPI Brain Research, The mRNA translation landscape in the synaptic neuropil. https://public.brain.mpg.de/dashapps/localseq/ Accessed 5 October 2021]. Overall, our findings emphasize the substantial contribution of local translation to maintaining synaptic protein levels and indicate that on-site translational control is an important mechanism to control synaptic strength

Assessment of Artifacts and Reproducibility across Spectral- and Time-Domain Optical Coherence Tomography Devices

Purpose To report the frequency of optical coherence tomography (OCT) scan artifacts and to compare macular thickness measurements, interscan reproducibility, and interdevice agreeability across 3 spectral-domain (SD) OCT (also known as Fourier domain; Cirrus HD-OCT, RTVue-100, and Topcon 3D-OCT 1000) devices and 1 time-domain (TD) OCT (Stratus OCT) device. Design Prospective, noncomparative, noninterventional case series. Participants Fifty-two patients seen at the New England Eye Center, Tufts Medical Center Retina Service, between February and August 2008. Methods Two scans were performed for each of the SD OCT protocols: Cirrus macular cube 512×128 (software version 3.0; Carl Zeiss Meditec, Inc., Dublin, CA), RTVue (E)MM5 and MM6 (software version 3.5; Optovue, Inc., Fremont, CA), Topcon 3D Macular and Radial (software version 2.12; Topcon, Inc., Paramus, NJ), in addition to 1 TD OCT scan via Stratus macular thickness protocol (software version 4.0; Carl Zeiss Meditec, Inc.). Scans were inspected for 6 types of OCT scan artifacts and were analyzed. Interscan reproducibility and interdevice agreeability were assessed by intraclass correlation coefficients (ICCs) and Bland-Altman plots, respectively. Main Outcome Measures Optical coherence tomography image artifacts, macular thickness, reproducibility, and agreeability. Results Time-domain OCT scans contained a significantly higher percentage of clinically significant improper central foveal thickness (IFT) after manual correction (11-μm change or more) compared with SD OCT scans. Cirrus HD-OCT had a significantly lower percentage of clinically significant IFT (11.1%) compared with the other SD OCT devices (Topcon 3D, 20.4%; Topcon Radial, 29.6%; RTVue (E)MM5, 42.6%; RTVue MM6, 24.1%; P = 0.001). All 3 SD OCT devices had central foveal subfield thicknesses that were significantly more than that of TD OCT after manual correction (P<0.0001). All 3 SD OCT devices demonstrated a high degree of reproducibility in the central foveal region (ICCs, 0.92–0.97). Bland-Altman plots showed low agreeability between TD and SD OCT scans. Conclusions Out of all OCT devices analyzed, cirrus HD-OCT scans exhibited the lowest occurrence of any artifacts (68.5%), IFT (40.7%), and clinically significant IFT (11.1%), whereas Stratus OCT scans exhibited the highest occurrence of clinically significant IFT. Further work on improving segmentation algorithm to decrease artifacts is warranted.Research to Prevent Blindness, Inc. (United States) (Challenge Grant)National Institutes of Health (U.S.) (Grant R01-EY11289-23)National Institutes of Health (U.S.) (Grant R01-EY13178-07)National Institutes of Health (U.S.) (Grant P30-EY008098)United States. Air Force Office of Scientific Research (Grant FA9550-07-1-0101)United States. Air Force Office of Scientific Research (Grant FA9550-07-1-0014

What Makes Some People Think Astrology Is Scientific?

Citizens in both North America and Europe are apt to read horoscope columns in newspapers and magazines. While some people read these casually and purely for entertainment, some believe that astrology has scientific status and can provide real insight into events and personality. Using data from a European survey, this article explores some of the reasons why some people think that astrology is scientific and how astrology is viewed in relation to other knowledge-producing practices. Three hypotheses in particular are tested. The first is that some Europeans lack the necessary scientific literacy to distinguish science from pseudoscience. The second is that people are confused about what astrology actually is. The third is derived from Adorno’s work on authoritarianism and the occult and postulates that those who adhere to authoritarian values are more likely to believe in astrological claims. Support is found for all three hypotheses. </jats:p

Do closed survey questions over-estimate public perceptions of food risks?

In this paper we show that the widely accepted methodology for the assessment of risk perception – Likert type survey questions featuring a set of risks with fixed response alternatives measuring the extent of worry or concern – may over-estimate food risk perception. Using a European representative sample survey (n=26,961) that included an open-ended question asking about problems and risks with food and eating, followed by a battery of closed questions assessing food risk perception we find a similar ranking of perceived food risks across the two methods. Across Europe the five priority concerns are chronic food related illness; food origins and quality; acute food related illness; chemical contamination, and adulteration of food. However, the discrepancies between mentioning a risk in the open ended question and the expression of worry about risks in the closed question are substantial. Of those who did not mention a specific risk category in the open question, between 60% and 83% (depending on risk category) expressed worry in the closed question. This parallels previous research on the fear of crime, showing that survey responses lead to greatly inflated estimates of the public’s fear of crime than is evidenced by qualitative questioning. It is also consistent with evidence from research on cognitive aspects of survey methodology suggesting that survey questions may frame the respondent’s thinking about an issue. We conclude with recommendations for the use of branched questions in the quantitative elicitation of public perceptions of risk