scholarly journals An inhalation anaesthesia approach for neonatal mice allowing streamlined stereotactic injection in the brain

2020 ◽  
Author(s):  
Hinze Ho ◽  
Adam Fowle ◽  
Marisa Coetzee ◽  
Ingo H. Greger ◽  
Jake F. Watson
Keyword(s):  
Standard Procedure ◽  
Scientific Research ◽  
Brain Regions ◽  
Intracerebral Injection ◽  
List Type ◽  
Inhalation Anaesthesia ◽  
Neonatal Mice ◽  
Long Term Study ◽  
3D Printed

AbstractInvestigating brain function requires tools and techniques to visualise, modify and manipulate neuronal tissue. One powerful and popular method is intracerebral injection of customised viruses, allowing expression of exogenous transgenes. This technique is a standard procedure for adult mice, and is used by laboratories worldwide. Use of neonatal animals in scientific research allows investigation of developing tissues, and enables long-term study of cell populations. However, procedures on neonatal mice are more challenging, due to the lack of reliable methods and apparatus for anaesthesia of these animals. Here, we report an inhalation-based protocol for anaesthesia of neonatal (P0-2) mice, and present a custom 3D-printed apparatus for maintenance of anaesthesia during surgical procedures. This approach significantly enhances animal welfare and facilitates wider and simpler use of neonatal rodents in scientific research. Our optimised method of anaesthesia enables a rapid method of stereotactic injection in neonatal mice for transduction of brain tissue. We demonstrate this procedure for targeted labelling of specific brain regions, and in vivo modification of tissue prior to organotypic culture. This anaesthetic approach can be readily employed by any laboratory, and will enable safer use of neonatal rodents across a diverse spectrum of scientific disciplines.HighlightsDevelopment of inhalation-based anaesthesia for early postnatal (P0-2) mice3D-printed mould allows anaesthetic maintenance for neonatal surgeryImproved mouse welfare through reliable neonatal inhalation anaesthesiaRapid procedure for brain transduction of mouse litter in under 2 hours

scholarly journals Seizures are a druggable mechanistic link between TBI and subsequent tauopathy

2020 ◽  
Author(s):  
Hadeel Alyenbaawi ◽  
Richard Kanyo ◽  
Laszlo F. Locskai ◽  
Razieh Kamali-Jamil ◽  
Michèle G. DuVal ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Cell Death ◽  
Brain Injury ◽  
Chronic Traumatic Encephalopathy ◽  
Brain Activity ◽  
Brain Regions ◽  
List Type ◽  
Larval Zebrafish ◽  
Post Traumatic

SummaryTraumatic brain injury (TBI) is a prominent risk factor for neurodegenerative diseases and dementias including chronic traumatic encephalopathy (CTE). TBI and CTE, like all tauopathies, are characterized by accumulation of Tau into aggregates that progressively spread to other brain regions in a prion-like manner. The mechanisms that promote spreading and cellular uptake of tau seeds after TBI are not fully understood, in part due to lack of tractable animal models. Here, we test the putative roles for excess neuronal activity and dynamin-dependent endocytosis in promoting the in vivo spread of tauopathy. We introduce ‘tauopathy reporter’ zebrafish expressing a genetically-encoded fluorescent Tau biosensor that reliably reports accumulation of human tau species when seeded via intra-ventricular brain injections. Subjecting zebrafish larvae to a novel TBI paradigm produced various TBI symptoms including cell death, hemorrhage, blood flow abnormalities, post–traumatic seizures, and Tau inclusions. Bath application of anticonvulsant drugs rescued TBI-induced tauopathy and cell death; these benefits were attributable to inhibition of post-traumatic seizures because co-application of convulsants reversed these beneficial effects. However, one convulsant drug, 4-Aminopyridine, unexpectedly abrogated TBI-induced tauopathy - this was due to its inhibitory action on endocytosis as confirmed via additional dynamin inhibitors. These data suggest a role for seizure activity and dynamin-dependent endocytosis in the prion-like seeding and spreading of tauopathy following TBI. Further work is warranted regarding anti-convulsants that dampen post-traumatic seizures as a route to moderating subsequent tauopathy. Moreover, the data highlight the utility of deploying in vivo Tau biosensor and TBI methods in larval zebrafish, especially regarding drug screening and intervention.Graphical AbstractHighlightsIntroduces first Traumatic Brain Injury (TBI) model in larval zebrafish, and its easyTBI induces clinically relevant cell death, haemorrhage & post-traumatic seizuresCa2+ imaging during TBI reveals spike in brain activity concomitant with seizuresTau-GFP Biosensor allows repeated in vivo measures of prion-like tau aggregationpost-TBI, anticonvulsants stop tauopathies akin to Chronic Traumatic Encephalopathy

scholarly journals Strong and specific connections between retinal axon mosaics and midbrain neurons revealed by large scale paired recordings

2021 ◽  
Author(s):  
Jérémie Sibille ◽  
Carolin Gehr ◽  
Jonathan I. Benichov ◽  
Hymavathy Balasubramanian ◽  
Kai Lun Teh ◽  
...  
Keyword(s):  
Single Cell ◽  
Retinal Ganglion Cells ◽  
Large Scale ◽  
Ganglion Cells ◽  
Brain Regions ◽  
High Density ◽  
List Type ◽  
Retinal Ganglion ◽  
Midbrain Neurons

SUMMARYThe superior colliculus (SC) is a midbrain structure that plays important roles in visually guided behaviors. Neurons in the SC receive afferent inputs from retinal ganglion cells (RGC), the output cells of the retina, but how SC neurons integrate RGC activity in vivo is unknown. SC neurons might be driven by strong but sparse retinal inputs, thereby reliably transmitting specific retinal functional channels. Alternatively, SC neurons could sum numerous but weak inputs, thereby extracting new features by combining a diversity of retinal signals. Here, we discovered that high-density electrodes simultaneously capture the activity and the location of large populations of retinal axons and their postsynaptic SC target neurons, permitting us to investigate the retinocollicular circuit on a structural and functional level in vivo. We show that RGC axons in the mouse are organized in mosaics that provide a single cell precise representation of the retina as input to SC. This isomorphic mapping between retina and SC builds the scaffold for highly specific wiring in the retinocollicular circuit which we show is characterized by strong connections and limited functional convergence, established in log-normally distributed connection strength. Because our novel method of large-scale paired recordings is broadly applicable for investigating functional connectivity across brain regions, we were also able to identify retinal inputs to the avian optic tectum of the zebra finch. We found common wiring rules in mammals and birds that provide a precise and reliable representation of the visual world encoded in RGCs to neurons in retinorecipient areas.HIGHLIGHTSHigh-density electrodes capture the activity of afferent axons and target neurons in vivoRetinal ganglion cells axons are organized in mosaicsSingle cell precise isomorphism between dendritic and axonal RGC mosaicsMidbrain neurons are driven by sparse but strong retinal inputsFunctional wiring of the retinotectal circuit is similar in mammals and birds

LACK OF EFFECT OF CORTICOSTEROIDS ON THE IN VIVO DISAPPEARANCE OF SULFHYDRYL-INHIBITED AND ANTIBODY-COATED ERYTHROCYTES

1964 ◽  
Vol 47 (3_Suppl) ◽  
pp. S28-S36
Author(s):  
Kailash N. Agarwal
Keyword(s):  
Red Cells ◽  
List Type ◽  
Red Cell

ABSTRACT Red cells were incubated in vitro with sulfhydryl inhibitors and Rhantibody with and without prior incubation with prednisolone-hemisuccinate. These erythrocytes were labelled with Cr51 and P32 and their disappearance in vivo after autotransfusion was measured. Prior incubation with prednisolone-hemisuccinate had no effect on the rate of red cell disappearance. The disappearance of the cells was shown to take place without appreciable intravascular destruction.

STUDIES IN CONGENITAL GENERALIZED LIPODYSTROPHY

1973 ◽  
Vol 72 (3) ◽  
pp. 495-505 ◽  
Author(s):  
Oddmund Søvik ◽  
Svein Oseid
Keyword(s):  
Biological Activity ◽  
Insulin Response ◽  
Epididymal Adipose Tissue ◽  
Large Individual ◽  
Immunoreactive Insulin ◽  
List Type ◽  
Glucose Load ◽  
Congenital Generalized Lipodystrophy ◽  
The One

ABSTRACT The biological activity of plasma insulin from 4 cases of congenital generalized lipodystrophy has been studied, using rat diaphragm and epididymal adipose tissue in vivo. The results are compared with previous data on plasma immunoreactive insulin obtained in these patients. 2 of the 4 cases exhibited unusually high biological insulin activities during the fasting state as well as after an intravenous (iv) glucose load. In the fat pad assay activities as high as 10 000 μU insulin per ml were observed. During childhood the biological insulin activities were generally high, although there were large individual variations. However, in the one case studied after the age of puberty, the insulin response to a glucose load was negligible. Taken together, the biological and immunological activities observed strongly suggest the presence of pancreatic insulin in these patients. It appears that the circulating insulin has a fully biological activity. The decreasing insulin activities after cessation of growth are in agreement with the appearance of frank diabetes at this time.

scholarly journals Growth Factor Therapy for Parkinson’s Disease: Alternative Delivery Systems

2021 ◽  
pp. 1-7
Author(s):  
Sarah Jarrin ◽  
Abrar Hakami ◽  
Ben Newland ◽  
Eilís Dowd
Keyword(s):  
Parkinson’S Disease ◽  
Gene Therapy ◽  
Parkinson's Disease ◽  
Growth Factors ◽  
Growth Factor ◽  
Ex Vivo ◽  
Brain Regions ◽  
Delivery Systems ◽  
Alternative Delivery

Despite decades of research and billions in global investment, there remains no preventative or curative treatment for any neurodegenerative condition, including Parkinson’s disease (PD). Arguably, the most promising approach for neuroprotection and neurorestoration in PD is using growth factors which can promote the growth and survival of degenerating neurons. However, although neurotrophin therapy may seem like the ideal approach for neurodegenerative disease, the use of growth factors as drugs presents major challenges because of their protein structure which creates serious hurdles related to accessing the brain and specific targeting of affected brain regions. To address these challenges, several different delivery systems have been developed, and two major approaches—direct infusion of the growth factor protein into the target brain region and in vivo gene therapy—have progressed to clinical trials in patients with PD. In addition to these clinically evaluated approaches, a range of other delivery methods are in various degrees of development, each with their own unique potential. This review will give a short overview of some of these alternative delivery systems, with a focus on ex vivo gene therapy and biomaterial-aided protein and gene delivery, and will provide some perspectives on their potential for clinical development and translation.

scholarly journals Cortical neurons exhibit diverse myelination patterns that scale between mouse brain regions and regenerate after demyelination

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cody L. Call ◽  
Dwight E. Bergles
Keyword(s):  
Cortical Neurons ◽  
Regional Differences ◽  
Brain Regions ◽  
Axon Diameter ◽  
Neuronal Identity ◽  
Cortical Areas ◽  
Myelin Sheaths ◽  
Parvalbumin Interneurons ◽  
Selection Of

ABSTRACTAxons in the cerebral cortex show a broad range of myelin coverage. Oligodendrocytes establish this pattern by selecting a cohort of axons for myelination; however, the distribution of myelin on distinct neurons and extent of internode replacement after demyelination remain to be defined. Here we show that myelination patterns of seven distinct neuron subtypes in somatosensory cortex are influenced by both axon diameter and neuronal identity. Preference for myelination of parvalbumin interneurons was preserved between cortical areas with varying myelin density, suggesting that regional differences in myelin abundance arises through local control of oligodendrogenesis. By imaging loss and regeneration of myelin sheaths in vivo we show that myelin distribution on individual axons was altered but overall myelin content on distinct neuron subtypes was restored. Our findings suggest that local changes in myelination are tolerated, allowing regenerated oligodendrocytes to restore myelin content on distinct neurons through opportunistic selection of axons.

scholarly journals The pharmacokinetics of [18F]UCB-H revisited in the healthy non-human primate brain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sébastien Goutal ◽  
Martine Guillermier ◽  
Guillaume Becker ◽  
Mylène Gaudin ◽  
Yann Bramoullé ◽  
...  
Keyword(s):  
Slow Component ◽  
Specific Binding ◽  
Compartment Model ◽  
Brain Regions ◽  
Volume Of Distribution ◽  
Pharmacokinetic Data ◽  
Limited Information ◽  
Positron Emission ◽  
Human Primate

Abstract Background Positron Emission Tomography (PET) imaging of the Synaptic Vesicle glycoprotein (SV) 2A is a new tool to quantify synaptic density. [18F]UCB-H was one of the first promising SV2A-ligands to be labelled and used in vivo in rodent and human, while limited information on its pharmacokinetic properties is available in the non-human primate. Here, we evaluate the reliability of the three most commonly used modelling approaches for [18F]UCB-H in the non-human cynomolgus primate, adding the coupled fit of the non-displaceable distribution volume (VND) as an alternative approach to improve unstable fit. The results are discussed in the light of the current state of SV2A PET ligands. Results [18F]UCB-H pharmacokinetic data was optimally fitted with a two-compartment model (2TCM), although the model did not always converge (large total volume of distribution (VT) or large uncertainty of the estimate). 2TCM with coupled fit K1/k2 across brain regions stabilized the quantification, and confirmed a lower specific signal of [18F]UCB-H compared to the newest SV2A-ligands. However, the measures of VND and the influx parameter (K1) are similar to what has been reported for other SV2A ligands. These data were reinforced by displacement studies using [19F]UCB-H, demonstrating only 50% displacement of the total [18F]UCB-H signal at maximal occupancy of SV2A. As previously demonstrated in clinical studies, the graphical method of Logan provided a more robust estimate of VT with only a small bias compared to 2TCM. Conclusions Modeling issues with a 2TCM due to a slow component have previously been reported for other SV2A ligands with low specific binding, or after blocking of specific binding. As all SV2A ligands share chemical structural similarities, we hypothesize that this slow binding component is common for all SV2A ligands, but only hampers quantification when specific binding is low.

Design, Fabrication, and Accuracy of a Novel Noncovering Lock-Mechanism Bilateral Patient-Specific Drill Guide Template for Nondeformed and Deformed Thoracic Spines

2021 ◽  
pp. 155633162199633
Author(s):  
Mehran Ashouri-Sanjani ◽  
Shima Mohammadi-Moghadam ◽  
Parisa Azimi ◽  
Navid Arjmand
Keyword(s):  
Thoracic Spine ◽  
Sagittal Plane ◽  
Ct Scanning ◽  
Entry Point ◽  
In Vivo Studies ◽  
Patient Specific ◽  
Plane Angle ◽  
Severe Scoliosis ◽  
3D Printed

Background: Pedicle screw (PS) placement has been widely used in fusion surgeries on the thoracic spine. Achieving cost-effective yet accurate placements through nonradiation techniques remains challenging. Questions/Purposes: Novel noncovering lock-mechanism bilateral vertebra-specific drill guides for PS placement were designed/fabricated, and their accuracy for both nondeformed and deformed thoracic spines was tested. Methods: One nondeformed and 1 severe scoliosis human thoracic spine underwent computed tomographic (CT) scanning, and 2 identical proportions of each were 3-dimensional (3D) printed. Pedicle-specific optimal (no perforation) drilling trajectories were determined on the CT images based on the entry point/orientation/diameter/length of each PS. Vertebra-specific templates were designed and 3D printed, assuring minimal yet firm contacts with the vertebrae through a noncovering lock mechanism. One model of each patient was drilled using the freehand and one using the template guides (96 pedicle drillings). Postoperative CT scans from the models with the inserted PSs were obtained and superimposed on the preoperative planned models to evaluate deviations of the PSs. Results: All templates fitted their corresponding vertebra during the simulated operations. As compared with the freehand approach, PS placement deviations from their preplanned positions were significantly reduced: for the nonscoliosis model, from 2.4 to 0.9 mm for the entry point, 5.0° to 3.3° for the transverse plane angle, 7.1° to 2.2° for the sagittal plane angle, and 8.5° to 4.1° for the 3D angle, improving the success rate from 71.7% to 93.5%. Conclusions: These guides are valuable, as the accurate PS trajectory could be customized preoperatively to match the patients’ unique anatomy. In vivo studies will be required to validate this approach.

scholarly journals Fabrication of 3D-Printed Interpenetrating Hydrogel Scaffolds for Promoting Chondrogenic Differentiation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2146
Author(s):  
Jian Guan ◽  
Fu-zhen Yuan ◽  
Zi-mu Mao ◽  
Hai-lin Zhu ◽  
Lin Lin ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Elastic Modulus ◽  
Chondrogenic Differentiation ◽  
Marker Genes ◽  
Self Healing ◽  
Polyethylene Glycol Diacrylate ◽  
3D Microenvironment ◽  
3D Printed

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.

scholarly journals In vivo synaptic density relates to glucose metabolism at rest in healthy subjects, but is strongly modulated by regional differences

2021 ◽  
pp. 0271678X2098150
Author(s):  
June van Aalst ◽  
Jenny Ceccarini ◽  
Stefan Sunaert ◽  
Patrick Dupont ◽  
Michel Koole ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Medial Temporal Lobe ◽  
Regional Differences ◽  
Specific Binding ◽  
Aerobic Glycolysis ◽  
Glucose Consumption ◽  
Brain Regions ◽  
Synaptic Density ◽  
Energy Demands

Preclinical and postmortem studies have suggested that regional synaptic density and glucose consumption (CMRGlc) are strongly related. However, the relation between synaptic density and cerebral glucose metabolism in the human brain has not directly been assessed in vivo. Using [11C]UCB-J binding to synaptic vesicle glycoprotein 2 A (SV2A) as indicator for synaptic density and [18F]FDG for measuring cerebral glucose consumption, we studied twenty healthy female subjects (age 29.6 ± 9.9 yrs) who underwent a single-day dual-tracer protocol (GE Signa PET-MR). Global measures of absolute and relative CMRGlc and specific binding of [11C]UCB-J were indeed highly significantly correlated ( r > 0.47, p < 0.001). However, regional differences in relative [18F]FDG and [11C]UCB-J uptake were observed, with up to 19% higher [11C]UCB-J uptake in the medial temporal lobe (MTL) and up to 17% higher glucose metabolism in frontal and motor-related areas and thalamus. This pattern has a considerable overlap with the brain regions showing different levels of aerobic glycolysis. Regionally varying energy demands of inhibitory and excitatory synapses at rest may also contribute to this difference. Being unaffected by astroglial and/or microglial energy demands, changes in synaptic density in the MTL may therefore be more sensitive to early detection of pathological conditions compared to changes in glucose metabolism.

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