Biotinylated dextran amine anterograde tracing of the canine corticospinal tract

In this study, biotinylated dextran amine （BDA） was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were visible in the left cortical motor area after injection. In the left medulla oblongata, the BDA-labeled corticospinal tract was evenly distributed, with green fluorescence that had a clear boundary with the surrounding tissue. The BDA-positive corticospinal tract entered into the right lateral funiculus of the spinal cord and descended into the posterior part of the right lateral funiculus, close to the posterior horn, from cervical to sacral segments. There was a small amount of green fluorescence in the sacral segment. The distribution of BDA labeling in the canine central nervous system was consistent with the course of the corticospinal tract. Fluorescence labeling for BDA gradually diminished with time after injection. Our findings indicate that the BDA anterograde tracing technique can be used to visualize the localization and trajectory of the corticospinal tract in the canine central nervous system.

A new anterograde trans-synaptic tracer based on Sindbis virus

Mapping neural circuits is critical for understanding the structure and function of the nervous system.Engineered viruses are a valuable tool for tracing neural circuits.However,current tracers do not fully meet the needs for this approach because of various drawbacks,such as toxicity and characteristics that are difficult to modify.Therefore,there is an urgent need to develop a new tracer with low toxicity and that allows for long-term studies.In this study,we constructed an engineered Sindbis virus(SINV)expressing enhanced green fluorescent protein(EGFP)reporter gene(SINV-EGFP)and found that it had no significant difference in biological characterization compared with the wild-type Sindbis virus in BHK-21 cells and neurons in vitro.We injected the virus into the visual circuit of mouse brain and found that the virus infected neurons in the local injected site and anterogradely spread in the neural circuits.Although the efficiency of transmission was limited,the findings demonstrate that SINV can be used as a new anterograde tracer to map neural circuits in mouse brain and that it spreads exclusively in the anterograde direction.Further,use of SINV in mouse brain research will provide longer time windows for circuit tracing than is possible with herpes simplex virus and vesicular stomatitis virus tracers.

Lost in the Present: Anterograde Amnesia and Medical Decision Making Capacity

Although there have been a limited number of case reports of human bilateral hippocampal injury, none of these have addressed the impact of such injuries on medical decision making capacity. The authors present a case of an elderly man with discrete bilateral hippocampal injury. As a result of his injury, the patient was hopelessly “lost in the present” and only retained the basic cognitive functions necessary to have decision making capacity for a limited period of time. He was unable to appreciate the nature of his injury, the potential risks involved in his decisions, and the recommended course of treatment longer than a few minutes. The patient’s resultant neurocognitive deficits left him lacking medical decision making capacity, a likely outcome for patients with persistent anterograde amnesia.

HSV-1 H129-Derived Anterograde Neural Circuit Tracers:Improvements, Production, and Applications

Anterograde viral tracers are powerful and essential tools for dissecting the output targets of a brain region of interest. They have been developed from herpes simplex virus 1(HSV-1) strain H129(H129), and have been successfully applied to map diverse neural circuits.Initially, the anterograde polysynaptic tracer H129-G4 was used by many groups. We then developed the first monosynaptic tracer, H129-dTK-tdT, which was highly successful, yet improvements are needed. Now, by inserting another tdTomato expression cassette into the H129-dTK-tdT genome, we have created H129-dTK-T2, an updated version of H129-dTK-tdT that has improved labeling intensity. To help scientists produce and apply our H129-derived viral tracers, here we provide the protocol describing our detailed and standardized procedures. Commonly-encountered technical problems and their solutions are also discussed in detail. Broadly, the dissemination of this protocol will greatly support scientists to apply these viral tracers on a large scale.

Surgical treatment of a rare complication after endoscopic stent placement for anastomotic leakage after esophageal resection

The best approach to achieve cure in esophageal cancer is a combination of chemo-radiation and surgery. However, complications occur in half of patients. The current report, reports a rare but severe complication: Complete obstruction of the esophagus, induced by preoperative chemo-radiation therapy. Normally, strictures are treated by repeated dilatations, however, in case of complete obstruction, the perforation rate of standard blind anterograde wire access and dilation is severely increased. In order to minimize the risk of perforations, the rendezvous technique was introduced. This technique involves an anterograde approach in combination with a retrograde approach in order to open and dilatate the esophagus. While technical success rates between 83% and 100% have been reported in literature, data on clinical outcomes are scarcer. The limited amount of studies available claim that success was achieved in almost half of patients. The patient in our case currently has an oral diet without restrictions and rates his quality of life with a VAS-score ten out of ten.

Is Marcus Gunn jaw winking a primitive reflex？ Rat neuroanatomy

AIM： To investigate a possible trigeminal proprioceptive- oculomotor neural pathway and explore possible synaptic connections between neurons in this pathway. Attempt to bring a new insight to mechanism of Marcus Gunn syndrome （MGS）. METHODS： Anterograde and retrograde tract tracing was applied and combined with immunofluorescent stain in rats. After electrophysiological identifying mesencephalic trigeminal nucleus （Vine） neurons, intracellular injection of tracer was performed to trace axon trajectory. RESULTS： Following injections of anterograde tracers into the Vine, labeled terminals were observed ipsilateral in oculomotor and trochlear nuclei （Ill/IV）, as well as in their premotor neurons in interstitial nucleus of Cajal and Darkschewitsch nucleus （INC/DN）. Combining with choline acetyltransferase （CHAT） immunofluorescent stain, it showed that Vme projecting terminals contact upon ChAT positive Ill/IV motoneurons under confocal microscope. By retrograde labeling premotor neurons of the III, it showed that Vme neuronal terminals contact with retrogradely labeled pre-oculomotor neurons in the INCIDN. Axons of intraceiiularly labeled Vme neurons that respond to electric stimuli of the masseter nerve traveled into the ipsilateral III. CONCLUSION： There may exist a trigeminal propdoceptive- oculomotor system neural circuit in the rat, which is probably related to vertical-torsional eye movements. Possible association of this pathway with MGS etiology was discussed.

Chondroitinase ABC treatment of injured spinal cord in rats Evaluation of long-term outcomes

Chondroitin sulfate proteoglycans （CSPGs） which are produced by mature oligodendrocytes and reactive astrocytes can be upregulated after spinal cord injury and contribute to regenerative failure. Chondroitinase ABC （ChABC） digests glycosaminoglycan chains on CSPGs and can thereby overcome CSPG-mediated inhibition. However, many current studies have used an incomplete spinal cord injury model, and examined results after 8-12 weeks of ChABC treatment. In this study, a complete rat spinal cord transection injury model was used to study the long-term effects of ChABC treatment by subarachnoid catheter. Pathology of spinal cord regeneration was compared with control 24 weeks following ChABC treatment using immunohistochemistry and axon tracing techniques. At 24 weeks after injury, neurofilament 200 expression was significantly greater in the ChABC treatment group compared with the transection group. In the ChABC treatment group, axonal growth was demonstrated by a large number of biotinylated dextran amine positive axons caudal to, or past, the epicenter of injury. Biotinylated dextran amine-labeled fibers were found in the proximal end of the spinal cord in the transection alone group. These results confirm that ChABC can promote axon growth, neural regeneration, and repair after spinal cord injury in rats long after the initial injury.

Optimal use of fielder XT guidewire enhances the success rate of chronic total occlusion percutaneous coronary intervention

BACKGROUND Chronic total occlusion(CTO) is found in 18-31% of patients who undergo coronary angiography. Successful recanalization of CTOs is associated with reduced recurrent angina pectoris rates and increased long-term survival.Although the success rate of CTO percutaneous coronary intervention(CTO-PCI)has improved, CTO-PCI remains technically challenging. The Fielder XT guidewire was designed for CTO lesions. To validate whether the use of the guidewire increases the success rate, we compared the results of CTO-PCI with or without the guidewire. We hypothesized that the use of Fielder XT guidewire can increase the success rate of CTO-PCI.AIM To investigate whether the use of Fielder XT guidewire increases the final procedural success of CTO-PCI via the anterograde approach.METHODS Between January 2013 and December 2015, a retrospective study was conducted on 1230 consecutive patients with CTO who received PCI via the anterograde approach at the General Hospital of Northern Theater Command. The patients were divided into an XT Group(n = 686) and a no-XT Group(n = 544) depending on whether Fielder XT guidewire was used. Both groups were compared for clinical parameters, lesion-related characteristics, procedural outcomes and inhospital complications. The data were statistically analyzed using Pearson's χ~2 test for categorical variables, and Students' t test was used to compare the quantitative data. Significant independent factors and a risk ratio with 95%confidence interval(CI) were assessed by multivariate logistic regression analysis.RESULTS In total, 1230 patients were recruited; 75.4% of the patients were male, and 55.8%of the patients were in the XT group. The overall success rate was 83.9%, with87.8% in the XT group. Based on multivariate logistic regression analysis, factors positively associated with procedural success were the use of Fielder XT guidewire(P = 0.005, 95%CI: 1.172-2.380) and systolic blood pressure(P = 0.011,95%CI: 1.003-1.022), while factors negatively associated with procedural success were blunt stump(P = 0.013, 95%CI: 1.341-11.862), male sex(P = 0.016, 95%CI:0.363-0.902), New York Heart Association(NYHA) class(P = 0.035, 95%CI: 0.553-0.979), contrast amount(P = 0.018, 95%CI: 0.983-0.998) and occlusion time(P =0.009, 95%CI: 0.994-0.999). No significant differences were found between the XT group and the no-XT group with respect to clinical parameters, lesion-related characteristics, coronary artery rupture [3(0.4%) vs 8(1.5%), P = 0.056], inhospital death [2(0.3%) vs 6(1.1%), P = 0.079] or in-hospital target lesion revascularization [3(0.4%) vs 7(1.3%), P < 0.099]. However, there were significant differences between the groups with respect to success rate [602(87.8%) vs 430(79.0%), P < 0.001], procedure time [(74 ± 23) vs(83 ± 21), P < 0.001], stent length[(32.0 ± 15.8) vs(37.3 ± 17.6), P < 0.001], contrast amount [(148 ± 46) vs(166 ± 43),P < 0.001], post-PCI myocardial infarction [43(6.3%) vs 59(10.8%), P = 0.004],major adverse cardiovascular event [44(6.4%) vs 57(10.7%), P = 0.007], side branch loss [31(4.5%) vs 44(8.1%), P = 0.009], contrast-induced nephropathy [29(4.2%) vs 40(7.4%), P = 0.018] and no reflow [8(1.2%) vs 14(2.9%), P = 0.034].CONCLUSION The use of Fielder XT guidewire shortens the Procedure and increases the success rate of CTO-PCI, and is also associated with reduced complication rates.

Compression Test and Finite Element Analysis for Failure Criterion of the Tibial Post of a Posterior-Stabilized Knee Prosthesis

Post cam mechanism of Posterior Stabilized (PS) knee prostheses is useful to realize intrinsic stability for cases with severe degeneration. However, some retrieval studies report severe failure of the polyethylene tibial post. We thought that severe failures were caused by high loads during daily activities. In the current study, we performed a compression test and a finite element analysis of the mechanical forces produced in the tibial post in posterior-stabilized knee prostheses in order to develop a specification for the tibial posts found in the polyethylene inserts of PS knee prostheses. Anterior tibial post impingement and posterior tibial post impingement were simulated. The surface pressure values detected in the compression test were consistent with those obtained in the FE analysis. Of the three designs, the lowest von Mises stress values were generated inside the round tibial post;therefore, tibial posts should be round. The risk of tibial post failure was low when 500 or 1000 N was loaded onto the knee joint. It was suggested that tibial post failure occurs when the shear strain at the base of the tibial post exceeds 0.1.

Risk Assessment of Retrograde Intramedullary Nailing for Proximal Humeral Fracture

In proximal humeral fracture except AO classification 11A1, fixations with a locking plate and nails are recommended. We performed mechanical tests to investigate whether retrograde intramedullary nailing has fixation stability comparable to those of anterograde intramedullary nailing and locking plate which achieve clinically favorable outcomes. In retrograde intramedullary nailing, a nail entry point is made in the diaphysis, for which reduction of stiffness of the humerus is of concern. Thus, we investigated the influence of a nail entry point made in the diaphysis on humeral strength. Retrograde intramedullary nailing had fixation stability against bending and a force loaded in the rotation direction comparable to those of anterograde intramedullary nail and locking plate. Displacement by the main external force loaded on the humerus, compressive load, was less than half in the bone fixed by retrograde intramedullary nailing compared with that in the bone fixed with a locking plate, showing favorable fixation stability. It was clarified that stiffness of the humerus against rotation and a load in the compression direction is not reduced by a nail entry point made by retrograde intramedullary nailing.

Morphological Tracing and Functional Identification of Monosynaptic Connections in the Brain:A Comprehensive Guide

Behavioral studies play a crucial role in unraveling the mechanisms underlying brain function.Recent advances in optogenetics,neuronal typing and labeling,and circuit tracing have facilitated the dissection of the neural circuitry involved in various important behaviors.The identification of monosynaptic connections,both upstream and downstream of specific neurons,serves as the foundation for understanding complex neural circuits and studying behavioral mechanisms.However,the practical implementation and mechanistic understanding of monosynaptic connection tracing techniques and functional identification remain challenging,particularly for inexperienced researchers.Improper application of these methods and misinterpretation of results can impede experimental progress and lead to erroneous conclusions.In this paper,we present a comprehensive description of the principles,specific operational details,and key steps involved in tracing anterograde and retrograde monosynaptic connections.We outline the process of functionally identifying monosynaptic connections through the integration of optogenetics and electrophysiological techniques,providing practical guidance for researchers.

Functional map of the macroglomerular complex of male Helicoverpaarmigera

The mechanism of sex pheromone reception in the male cotton bollworm Helicoverpa armigera has been extensively studied because it has become an important model system for understanding insect olfaction.However,the pathways of pheromone processing from the antenna to the primary olfactory center in H.armigera have not yet been clarified.Here,the physiology and morphology of male H.armigera olfactory sensory neurons(OSNs)were studied using single sensillum recording along with anterograde filling and intracellular recording with retrograde filling.OSNs localized in type A sensilla responded to the major pheromone component cis-11-hexadecenal,and the axonal terminals projected to the cumulus(Cu)of the macroglomerular complex(MGC).The OSNs in type B sensilla respondcd to the bchavioral antagonist cis-9-tetradecenal,and the axonal terminals projected to the dorsomedial anterior(DMA)unit of the MGC.In type C sensilla,there were 2 OSNs:one that responded to cis-9-tetradecenal and cis-11-hexadecenol with the axonal terminals projecting to the DMA,and another that responded to the secondary pheromone components cis-9-hexadecenal and cis-9-tetradecenal with the axonal terminals projecting to the dorsomedial posterior(DMP)unit of the MGC.Type A and type B sensilla also housed the secondary OSNs,which were silent neurons with axonal terminals projected to the glomerulus G49 and DMP.Overall,the neural pathways that carry information on attractiveness and aversiveness in response to female pheromone components in H.armigera exhibit distinct projections to the MGC units.

Trans-synaptic Neural Circuit-Tracing with Neurotropic Viruses

A central objective in deciphering the nervous system in health and disease is to define the connections of neurons. The propensity of neurotropic viruses to spread among synaptically-linked neurons makes them ideal for mapping neural circuits. So far, several classes of viral neuronal tracers have become available and provide a powerful toolbox for delineating neural networks. In this paper, we review the recent developments of neurotropic viral tracers and highlight their unique properties in revealing patterns of neuronal connections.

Viral Tools for Neural Circuit Tracing

Neural circuits provide an anatomical basis for functional networks.Therefore,dissecting the structure of neural circuits is essential to understanding how the brain works.Recombinant neurotropic viruses are important tools for neural circuit tracing with many advantages over non-viral tracers:they allow for anterograde,retrograde,and trans-synaptic delivery of tracers in a cell type-specific,circuit-selective manner.In this review,we summarize the recent developments in the viral tools for neural circuit tracing,discuss the key principles of using viral tools in neuroscience research,and highlight innovations for developing and optimizing viral tools for neural circuit tracing across diverse animal species,including nonhuman primates.

Lighting Up Neural Circuits by Viral Tracing

Neurons are highly interwoven to form intricate neural circuits that underlie the diverse functions of the brain.Dissecting the anatomical organization of neural circuits is key to deciphering how the brain processes information,produces thoughts,and instructs behaviors.Over the past decades,recombinant viral vectors have become the most commonly used tracing tools to define circuit architecture.In this review,we introduce the current categories of viral tools and their proper application in circuit tracing.We further discuss some advances in viral tracing strategy and prospective innovations of viral tools for future study.

Shanghai Tower

Owner:Shanghai Tower Construction & Development Co.,Ltd.Contractor:Shanghai Construction Group Co.,Ltd.Architectural Designer:Gensler,USA Structural engineer:Thornton Tomasetti,USA Construction Drawing Designer:Tongji Architectural Design(Group)Co.,Ltd.With a height of 632 m,the Shanghai Tower stands