RNA aptamer reveals nuclear TDP-43 pathology is an early aggregation event that coincides with STMN-2 cryptic splicing and precedes clinical manifestation in ALS

TDP-43 is an aggregation-prone protein which accumulates in the hallmark pathological inclusions of amyotrophic lateral sclerosis (ALS). However, the analysis of deeply phenotyped human post-mortem samples has shown that TDP-43 aggregation, revealed by standard antibody methods, correlates poorly with symptom manifestation. Recent identification of cryptic-splicing events, such as the detection of Stathmin-2 (STMN-2) cryptic exons, are providing evidence implicating TDP-43 loss-of-function as a potential driving pathomechanism but the temporal nature of TDP-43 loss and its relation to the disease process and clinical phenotype is not known. To address these outstanding questions, we used a novel RNA aptamer, TDP-43APT, to detect TDP-43 pathology and used single molecule in situ hybridization to sensitively reveal TDP-43 loss-of-function and applied these in a deeply phenotyped human post-mortem tissue cohort. We demonstrate that TDP-43APT identifies pathological TDP-43, detecting aggregation events that cannot be detected by classical antibody stains. We show that nuclear TDP-43 pathology is an early event, occurring prior to cytoplasmic accumulation and is associated with loss-of-function measured by coincident STMN-2 cryptic splicing pathology. Crucially, we show that these pathological features of TDP-43 loss-of-function precede the clinical inflection point and are not required for region specific clinical manifestation. Furthermore, we demonstrate that gain-of-function in the form of extensive cytoplasmic accumulation, but not loss-of-function, is the primary molecular correlate of clinical manifestation. Taken together, our findings demonstrate implications for early diagnostics as the presence of STMN-2 cryptic exons and early TDP-43 aggregation events could be detected prior to symptom onset, holding promise for early intervention in ALS.

Intense chorus waves are the cause of flux-limiting in the heart of the outer radiation belt

Chorus waves play a key role in outer Van Allen electron belt dynamics through cyclotron resonance. Here, we use Van Allen Probes data to reveal a new and distinct population of intense chorus waves excited in the heart of the radiation belt during the main phase of geomagnetic storms. The power of the waves is typically ~ 2-3 orders of magnitude greater than pre-storm levels, and are generated when fluxes of ~ 10-100 keV electrons approach or exceed the Kennel-Petschek limit. These intense chorus waves rapidly scatter electrons into the loss cone, capping the electron flux to a value close to the limit predicted by Kennel and Petschek over 50 years ago. Our results are crucial for understanding the limits to radiation belt fluxes, with accurate models likely requiring the inclusion of this chorus wave-driven flux-limiting process, that is independent of the acceleration mechanism or source responsible for enhancing the flux.

Cognition and brain iron deposition in whole grey matter regions and hippocampal subfields

Regional brain iron accumulation is observed in many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, and is associated with cognitive decline. We explored associations between age, cognition and iron content in grey matter regions and hippocampal subfields in 380 participants of the Aberdeen children of the 1950s cohort and their first-generation relatives (aged 26-72 years). Participants underwent cognitive assessment at the time of MRI scanning. Quantitative susceptibility mapping of these MRI data was used to assess iron content in grey matter regions and in hippocampal subfields. Principle component analysis was performed on cognitive test scores to create a general cognition score. Spline analysis was used with the Akaike information criterion to determine if order 1, 2 or 3 natural splines were optimal for assessing non-linear relationships between regional iron and age. Multivariate linear models were used to assess associations between regional iron and cognition. Higher iron correlated with older age in the left putamen across all ages and in the right putamen of only participants over 58. Whereas a decrease in iron with older age was observed in the right thalamus and left pallidum across all ages. Right amygdala iron levels were associated with poorer general cognition scores and poorer immediate recall scores. Iron was not associated with any measures of cognitive performance in other regions of interest. Our results suggest that, whilst iron in some regions was associated with cognitive performance, there is an overall lack of association between regional iron content and cognitive ability in cognitively healthy individuals.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Collaborative Research Activities of the Arase and Van Allen Probes

This paper presents the highlights of joint observations of the inner magnetosphere by the Arase spacecraft, the Van Allen Probes spacecraft, and ground-based experiments integrated into spacecraft programs. The concurrent operation of the two missions in 2017-2019 facilitated the separation of the spatial and temporal structures of dynamic phenomena occurring in the inner magnetosphere. Because the orbital inclination angle of Arase is larger than that of Van Allen Probes, Arase collected observations at higher L -shells up to L ∼ 10 . After March 2017, similar variations in plasma and waves were detected by Van Allen Probes and Arase. We describe plasma wave observations at longitudinally separated locations in space and geomagnetically-conjugate locations in space and on the ground. The results of instrument intercalibrations between the two missions are also presented. Arase continued its normal operation after the scientific operation of Van Allen Probes completed in October 2019. The combined Van Allen Probes (2012-2019) and Arase (2017-present) observations will cover a full solar cycle. This will be the first comprehensive long-term observation of the inner magnetosphere and radiation belts.

The impact of brain iron accumulation on cognition: A systematic review

Iron is involved in many processes in the brain including, myelin generation, mitochondrial function, synthesis of ATP and DNA and the cycling of neurotransmitters. Disruption of normal iron homeostasis can result in iron accumulation in the brain, which in turn can partake in interactions which amplify oxidative damage. The development of MRI techniques for quantifying brain iron has allowed for the characterisation of the impact that brain iron has on cognition and neurodegeneration. This review uses a systematic approach to collate and evaluate the current literature which explores the relationship between brain iron and cognition. The following databases were searched in keeping with a predetermined inclusion criterion: Embase Ovid, PubMed and PsychInfo (from inception to 31^st March 2020). The included studies were assessed for study characteristics and quality and their results were extracted and summarised. This review identified 41 human studies of varying design, which statistically assessed the relationship between brain iron and cognition. The most consistently reported interactions were in the Caudate nuclei, where increasing iron correlated poorer memory and general cognitive performance in adulthood. There were also consistent reports of a correlation between increased Hippocampal and Thalamic iron and poorer memory performance, as well as, between iron in the Putamen and Globus Pallidus and general cognition. We conclude that there is consistent evidence that brain iron is detrimental to cognitive health, however, more longitudinal studies will be required to fully understand this relationship and to determine whether iron occurs as a primary cause or secondary effect of cognitive decline.

Oxygen torus and its coincidence with EMIC wave in the deep inner magnetosphere: Van Allen Probe B and Arase observations

We investigate the longitudinal structure of the oxygen torus in the inner magnetosphere for a specific event found on 12 September 2017, using simultaneous observations from the Van Allen Probe B and Arase satellites. It is found that Probe B observed a clear enhancement in the average plasma mass (M) up to 3-4 amu at L = 3.3-3.6 and magnetic local time (MLT) = 9.0 h. In the afternoon sector at MLT ~ 16.0 h, both Probe B and Arase found no clear enhancements in M. This result suggests that the oxygen torus does not extend over all MLT but is skewed toward the dawn. Since a similar result has been reported for another event of the oxygen torus in a previous study, a crescent-shaped torus or a pinched torus centered around dawn may be a general feature of the O+ density enhancement in the inner magnetosphere. We newly find that an electromagnetic ion cyclotron (EMIC) wave in the H+ band appeared coincidently with the oxygen torus. From the lower cutoff frequency of the EMIC wave, the ion composition of the oxygen torus is estimated to be 80.6% H+, 3.4% He+, and 16.0% O+. According to the linearized dispersion relation for EMIC waves, both He+ and O+ ions inhibit EMIC wave growth and the stabilizing effect is stronger for He+ than O+. Therefore, when the H+ fraction or M is constant, the denser O+ ions are naturally accompanied by the more tenuous He+ ions, resulting in a weaker stabilizing effect (i.e., larger growth rate). From the Probe B observations, we find that the growth rate becomes larger in the oxygen torus than in the adjacent regions in the plasma trough and the plasmasphere.

Mechanical modulation of calf tail vertebral growth: implications for scoliosis progression

The purpose of this study was to determine whether compression and distraction applied to adjacent vertebrae in the calf tail could modulate vertebral growth. Seven 6-week-old calves had two pairs of adjacent tail vertebrae instrumented with an Ilizarov external fixator with calibrated springs designed to apply a 30-50-N axial load to the vertebrae. Data were obtained from 17 vertebrae loaded in compression and 4 vertebrae loaded in distraction. Vertebrae adjacent (cranial and caudal) to the instrumented vertebrae served as controls. The length of each vertebra on the postoperative radiograph was subtracted from the length of the same vertebra on the radiograph taken 6 months after the operation to calculate vertebral growth. The vertebrae loaded in compression had a growth rate of 68 +/- 42% of that of the controls. In contrast, the vertebrae loaded in distraction had a growth rate of 123 +/- 78% of that of the controls.

The magnocellular neurons of the hypothalamo-neurohypophyseal system display remarkable neuropeptidergic phenotypes leading to novel insights in neuronal cell biology

For decades the magnocellular neurons of the hypothalamo-neurophypophyseal system (HNS), in which either vasopressin or oxytocin are produced and released into the bloodstream, have been playing a pivotal role in fundamental discoveries in the nervous system. The primary structure of vasopressin and oxytocin was the first of all neuropeptides to be published, i.e., in the 1950s by the Nobel prize laureate Du Vigneaud. Moreover, many trend-setting discoveries have their origin in the HNS, which abundantly expresses vasopressin and oxytocin, clearly displays its function and is relatively easily to manipulate. Examples are the phenomenon of coexpression of neuropeptides, patch-clamping of nerve endings, axonal transport of RNA, neuroglia interactions and the behavioral effects. An extraordinarily intriguing example is the homozygous Brattleboro rat, which lacks vasopressin by a germ-line mutation, and has disclosed many of the fundamental characteristics of peptidergic neurons, and neurons in general. In this chapter we will discuss a few of them, in particular the recent data on mutations in vasopressin RNA. It is to be expected that the HNS will retain its informative role in the next decades.

Mechanical modulation of intervertebral disc thickness in growing rat tails

Progression of scoliosis deformity during growth is thought to be caused by asymmetrical loading, resulting in asymmetrical growth with vertebral and disc wedging in a "vicious cycle." The purpose of this study was to quantify the changes in disc thickness during growth in rat tails subjected to compression or distraction loading for 6 or 9 weeks, to investigate the hypothesis that disc growth is mechanically modulated. Six-week-old Sprague-Dawley rats were studied with compression loading (13 animals) or distraction loading (15 animals) applied to their tails, and there were 8 sham animals. Loading was applied to tail segments by means of an external ring fixator. Radiographic measurements of disc thickness were made at biweekly intervals. From the initial to final radiograph, compressed discs had reduced thickness averaging (+/-SD) 0.50 +/- 0.28 mm, distraction discs had average increased thickness of 0.20 +/- 0.42 mm, and sham discs lost an average of 0.21 +/- 0.18 mm of thickness (analysis of variance p < 0.001). There was an "initial change" in disc thickness averaging 0.18 +/- 0.32 mm in nonloaded discs, which was similar in magnitude to the elastic deformation and was attributed to disc swelling under anesthesia. These results indicate that growth in disc thickness is mechanically modulated by axial loading in growing rats.

Progression of vertebral wedging in an asymmetrically loaded rat tail model

STUDY DESIGN

A rat tail model was used to test the hypothesis that angulation and asymmetric axial compressive loading would lead to vertebral wedging because of asymmetric longitudinal growth in the physes.

OBJECTIVES

To study the effect of angulation and asymmetric loading on the progression of spinal curvature in a rat tail model.

SUMMARY OF BACKGROUND DATA

Large idiopathic scoliotic curves in children with significant growth remaining are the curves most likely to progress. The mechanism of progression of skeletal deformities is thought to be controlled by the Hueter-Volkmann law, whereby additional axial compression decelerates growth, and reduced axial compression accelerates growth. It has been hypothesized that spinal curvature leads to asymmetric loading transversely along the vertebral growth plate, causing progressive vertebral wedging by means of a vicious cycle.

METHODS

Two 32-mm diameter external ring fixators were glued to 0.7-mm pins that had been inserted percutaneously through the eighth and 10th caudal vertebra of 10 6-week-old Sprague-Dawley rats. Calibrated springs and 15 degrees wedges, mounted on stainless steel threaded rods passing through holes distributed around the rings, imposed a 30 degrees Cobb angle and axially compressed the instrumented vertebrae. Fluorochrome labels and radiographs were used to document the progression of vertebral wedging.

RESULTS

The wedging initially was entirely in the intervertebral discs, but by 6 weeks the wedging of the discs and vertebrae were approximately equal. Fluorochrome labeling confirmed that the vertebral wedging resulted from asymmetric growth in the physes.

CONCLUSIONS

This study shows that vertebrae, when asymmetrically loaded, become wedged. This is consistent with the concept of mechanically provoked progression of scoliotic deformities according to the Hueter-Volkmann law.

Mechanical modulation of vertebral body growth. Implications for scoliosis progression

STUDY DESIGN

The authors developed a rat-tail model to investigate the hypothesis that vertebral wedging during growth in progressive spinal deformities results from asymmetric loading in a "vicious cycle."

OBJECTIVES

To document growth curves with axial compression or distraction applied to tail vertebrae to determine whether compression load slows growth and distraction accelerates it.

SUMMARY OF BACKGROUND DATA

Progression of skeletal deformity during growth is believed to be governed by the Hueter-Volkmann law, but there is conflicting evidence to support this idea.

METHODS

Twenty-eight 6-week-old Sprague-Dawley rats were assigned to one of three groups: compression loading, distraction loading, or sham (apparatus applied without loading). Under general anesthesia, two 0.7-mm diameter stainless steel percutaneous pins were used to transfix each of two vertebrae. The pins were glued to 25-mm diameter external ring fixators. Springs (load rate, 35 g/mm) were installed on three stainless steel threaded rods that were passed through holes in each ring and compressed with nuts to apply compression or distraction forces between 25-75% of bodyweight. Vertebral growth rates in microns/day were measured by digitizing the length of the vertebrae images in radiographs taken 0, 1, 3, 5, 7, and 9 weeks later.

RESULTS

The loaded vertebrae grew at 68% of control rate for compressed vertebrae and at 114% for distracted vertebrae. (Differences statistically significant, P < 0.01 by analysis of variance.) For the compressed vertebrae, the pinned vertebrae, which were loaded at one of their two growth cartilages, grew at a reduced rate (85%), although this effect was not apparent for the distraction animals.

CONCLUSIONS

The findings confirm that vertebral growth is modulated by loading, according to the Hueter-Volkmann principle. The quantification of this relationship will permit more rational design of conservative treatment of spinal deformity during the adolescent growth spurt.

Reed Nesbit and pediatric urology

OBJECTIVES

To ascertain the pediatric urology experience and contributions of Reed Nesbit, a urologist known primarily as an educator, transurethral resectionist, and prostate expert.

METHODS

The writings of Nesbit and appropriate background references were analyzed.

RESULTS

Nesbit's contributions to pediatric urology, particularly the Cabot-Nesbit orchidopexy, the buttonhole preputial transposition, the dorsal tunical tuck for chordee, and the elliptical anastomosis were significant.

CONCLUSIONS

Nesbit's contributions to pediatric urology were innovative and enduring.

Taq DNA polymerase extension of internal primers blocks polymerase chain reactions allowing differential amplification of molecules with identical 5' and 3' ends

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Molecular cloning of a human thyrotropin receptor cDNA fragment. Use of highly degenerate, inosine containing primers derived from aligned amino acid sequences of a homologous family of glycoprotein hormone receptors

Autoantibodies to the thyrotropin (TSH) hormone receptor (TSH-R) are present in the sera of patients with thyroid autoimmune disease which are pathogenetic leading to hyperthyroidism of Graves' disease. Considerable interest has been focused on the cloning of the human TSH-R, which has until very recently, proven exceedingly difficult due to the very low receptor level expression on thyroid cells. We have used polymerase chain reaction and highly degenerate, inosine containing oligonucleotides derived from sequence alignments of the transmembrane regions 2 and 7 of a number of G-binding protein receptors including the lutropin/choriogonadotropin (LH/CG) receptors to amplify various cDNAs from human thyroid cDNA. Sequencing analysis of 27 different clones revealed that they fall into eight different groups. The very recent publication of the complete nucleotide sequence of the human TSH-R revealed that one of the groups (GT1) containing seven clones which had been sequenced belong to the human TSH-receptor. The sequence of all 7 GT1 clones was identical and in complete concordance with transmembrane regions 2 and 7 of the published TSH-R sequence. Our results show that by designing oligonucleotides to common transmembrane regions of G-binding proteins where the primers are biased in their sequence to the LH/CG receptors it is possible to amplify the TSH-R receptor sequence.

Isolation and properties of a new anticoagulant protein from commercial bovine testicular hyaluronidase

Bovine testicular hyaluronidase from various commercial sources showed the presence of an inhibitor of human plasma prothrombin time (PT). A testicular anticoagulant protein (TAP) was isolated from it by a 3-step procedure. The material was first passed through conconavalin-A-sepharose affinity chromatography where the anticoagulant material was separated from the hyaluronidase and protease which were retained by the column. In the second step the lower molecular weight proteins were removed by ultrafiltration. The supernatant which contained the anticoagulant protein was passed through the carboxymethyl cellulose column and the active material was eluted by 0.4 M NaCl solution. Sodium dodecyl sulfate (SDS) gel electrophoresis gave a molecular weight of approximately 35000. Unlike many small molecular weight proteins from bovine testes, TAP looses its anticoagulant property by heating for 30 minutes at 55 degrees C or by storage at pH 3.0 for 2 hours and it does not inhibit trypsin or thrombin. Its isoelectric pH was 9.7. Diisopropyl fluorophosphate (DFP) treated TAP was not effective as an anticoagulant.

Teaching effectiveness in coordinated undergraduate program in dietetics. Assessments of students, graduates, and program directors

The effect of practitioner experience on teaching effectiveness of faculty in coordinated undergraduate programs in dietetics (CUPs) was studied on the basis of ratings from program directors, students, and program graduates. Instruments to measure teaching effectiveness were developed that contained 36 items common to all teaching situations and 6 each related to teaching in clinical/community dietetics and to food service management. Four dimensions of effective teaching were identified using factor analysis: interpersonal skill, dietetic expertise, organizational focus, and clinical or practical orientation. Extensive practitioner experience did not contribute to teaching effectiveness.

Toxocara antibodies in veterinary personnel

The prevelance of antibodies to Toxocara canis was determined in 113 veterinary personnel from 22 animal clinics. One hundred and fourteen adult hospital in-patients served as controls. All participants completed a questionnaire supplying personal data and specifies regarding animal exposure and dog ownership. Antibodies to Toxocara were detected by enzyme linked immunosorbent assay (ELISA) employing as antigen, excretorysecretory products from second stage larvae of Toxocara canis.Toxocara antibodies were found in ten (8.8%) of 113 veterinary workers and in 11 (9.6%) of 114 controls. Antibody prevalence was no different between males and females. Toxocara infection was not associated with dog ownership in veterinary workers or in hospitalized controls. A breakdown of the specific occupations among veterinary personnel failed to show a difference in antibody prevalence, nor did years of service as a veterinary worker correlate with the presence of Toxocara antibody.Our results suggest that toxocariasis is not associated with direct humandog contact nor with occupational exposure to dogs.