A toolbox for studying cortical physiology in primates

Lesioning and neurophysiological studies have facilitated the elucidation of cortical functions and mechanisms of functional recovery following injury. Clinical translation of such studies is contingent on their employment in non-human primates (NHPs), yet tools for monitoring and modulating cortical physiology are incompatible with conventional NHP lesioning techniques. To address these challenges, we developed a toolbox demonstrated in seven macaques. We introduce the photothrombotic method to induce focal cortical lesions alongside a quantitative model for the design of lesion profiles based on experimental needs. Large-scale (~5 cm2) vascular and neural dynamics can be monitored and lesion induction can be validated in vivo with optical coherence tomography angiography and our electrocorticographic array, the latter of which also enables testing stimulation-based interventions. By combining optical and electrophysiological techniques in NHPs, we can enhance our understanding of cortical functions, investigate functional recovery mechanisms, integrate physiological and behavioral findings, and develop treatments for neurological disorders.

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Purification of the Antihemophilic Factor by Gel Filtration on Agarose

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651394 ◽

1969 ◽

Vol 22 (03) ◽

pp. 577-583 ◽

Cited By ~ 3

Author(s):

M.M.P Paulssen ◽

A.C.M.G.B Wouterlood ◽

H.L.M.A Scheffers

Keyword(s):

Factor Viii ◽

Plasma Proteins ◽

Large Scale ◽

Gel Filtration ◽

Large Scale Preparation ◽

Scale Preparation ◽

Antihemophilic Factor

SummaryFactor VIII can be isolated from plasma proteins, including fibrinogen by chromatography on agarose. The best results were obtained with Sepharose 6B. Large scale preparation is also possible when cryoprecipitate is separated by chromatography. In most fractions containing factor VIII a turbidity is observed which may be due to the presence of chylomicrons.The purified factor VIII was active in vivo as well as in vitro.

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The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657715 ◽

1997 ◽

Vol 78 (04) ◽

pp. 1202-1208 ◽

Cited By ~ 18

Author(s):

Marianne Kjalke ◽

Julie A Oliver ◽

Dougald M Monroe ◽

Maureane Hoffman ◽

Mirella Ezban ◽

...

Keyword(s):

Tissue Factor ◽

Active Site ◽

Large Scale ◽

Thrombin Generation ◽

Factor Viia ◽

Dependent Manner ◽

Antithrombotic Agent ◽

Before And After ◽

Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

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Acyl-Enzymes as Thrombolytic Agents in Dog Models of Venous Thrombosis and Pulmonary Embolism

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661069 ◽

1984 ◽

Vol 51 (02) ◽

pp. 248-253 ◽

Cited By ~ 22

Author(s):

R J Dupe ◽

P D English ◽

R A G Smith ◽

J Green

Keyword(s):

Pulmonary Embolism ◽

Side Effects ◽

Venous Thrombosis ◽

Active Site ◽

Acute Pulmonary Embolism ◽

Quantitative Model ◽

Beagle Dog ◽

Thrombosis Model ◽

Derivatives Of

SummaryA quantitative model of venous thrombosis in the beagle dog is described. The model was adapted to permit ageing of isolated experimental clots in vivo. A model of acute pulmonary embolism in this species is also described. In the venous thrombosis model, infusion of streptokinase (SK) or SK-activated human plasmin gave significant lysis but bolus doses of SK. plasmin complex were ineffective. Active site anisoylated derivatives of SK. plasminogen complex, SK-activated plasmin and activator-free plasmin were all active when given as bolus doses in both models. At lytic doses, the acyl-enzymes caused fewer side-effects attributable to plasminaemia than the corresponding unmodified enzymes.

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Naphthoquinones and derivatives for chemotherapy: perspectives and limitations of their anti-trypanosomatids activities

Current Pharmaceutical Design ◽

10.2174/1381612826666201109111802 ◽

2020 ◽

Vol 26 ◽

Author(s):

Luíza Dantas-Pereira ◽

Edézio F. Cunha-Junior ◽

Valter V. Andrade-Neto ◽

John F. Bower ◽

Guilherme A. M. Jardim ◽

...

Keyword(s):

Large Scale ◽

Neglected Tropical Diseases ◽

Folk Medicine ◽

Leishmania Species ◽

Parasitic Infections ◽

Mechanistic Analysis ◽

Leishmania Spp ◽

Nanomolar Range

: Chagas disease, Sleeping sickness and Leishmaniasis, caused by trypanosomatids Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp., respectively, are considered neglected tropical diseases, and they especially affect impoverished populations in the developing world. The available chemotherapies are very limited and a search for alternatives is still necessary. In folk medicine, natural naphthoquinones have been employed for the treatment of a great variety of illnesses, including parasitic infections. This review is focused on the anti-trypanosomatid activity and mechanistic analysis of naphthoquinones and derivatives. Among all the series of derivatives tested in vitro, naphthoquinone-derived 1,2,3-triazoles were very active on T. cruzi infective forms in blood bank conditions, as well as in amastigotes of Leishmania spp. naphthoquinones containing a CF3 on a phenyl amine ring inhibited T. brucei proliferation in the nanomolar range, and naphthopterocarpanquinones stood out for their activity on a range of Leishmania species. Some of these compounds showed a promising selectivity index (SI) (30 to 1900), supporting further analysis in animal models. Indeed, high toxicity to the host and inactivation by blood components are crucial obstacles to be overcome to use naphthoquinones and/or their derivatives for chemotherapy. Multidisciplinary initiatives embracing medicinal chemistry, bioinformatics, biochemistry, and molecular and cellular biology need to be encouraged to allow the optimization of these compounds. Large scale automated tests are pivotal for the efficiency of the screening step, and subsequent evaluation of both the mechanism of action in vitro and pharmacokinetics in vivo are essential for the development of a novel, specific and safe derivative, minimizing adverse effects.

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Implantable neural interfaces

10.1093/oso/9780199674923.003.0050 ◽

2018 ◽

Author(s):

Stefano Vassanelli

Keyword(s):

Brain Function ◽

Large Scale ◽

Ionic Channels ◽

Patch Clamp Technique ◽

Advantages And Disadvantages ◽

Optogenetic Stimulation ◽

Physical Interfaces ◽

The Brain

Establishing direct communication with the brain through physical interfaces is a fundamental strategy to investigate brain function. Starting with the patch-clamp technique in the seventies, neuroscience has moved from detailed characterization of ionic channels to the analysis of single neurons and, more recently, microcircuits in brain neuronal networks. Development of new biohybrid probes with electrodes for recording and stimulating neurons in the living animal is a natural consequence of this trend. The recent introduction of optogenetic stimulation and advanced high-resolution large-scale electrical recording approaches demonstrates this need. Brain implants for real-time neurophysiology are also opening new avenues for neuroprosthetics to restore brain function after injury or in neurological disorders. This chapter provides an overview on existing and emergent neurophysiology technologies with particular focus on those intended to interface neuronal microcircuits in vivo. Chemical, electrical, and optogenetic-based interfaces are presented, with an analysis of advantages and disadvantages of the different technical approaches.

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What Has Direct Cortical and Subcortical Electrostimulation Taught Us about Neurolinguistics?

The Oxford Handbook of Neurolinguistics ◽

10.1093/oxfordhb/9780190672027.013.8 ◽

2019 ◽

pp. 185-211

Author(s):

Hugues Duffau

Keyword(s):

White Matter ◽

Large Scale ◽

Functional Neuroimaging ◽

Great Accuracy ◽

Subcortical White Matter ◽

Cerebral Lesions ◽

Physiological Basis ◽

Postoperative Mri ◽

The Brain

Investigating the neural and physiological basis of language is one of the most important challenges in neurosciences. Direct electrical stimulation (DES), usually performed in awake patients during surgery for cerebral lesions, is a reliable tool for detecting both cortical and subcortical (white matter and deep grey nuclei) regions crucial for cognitive functions, especially language. DES transiently interacts locally with a small cortical or axonal site, but also nonlocally, as the focal perturbation will disrupt the entire subnetwork sustaining a given function. Thus, in contrast to functional neuroimaging, DES represents a unique opportunity to identify with great accuracy and reproducibility, in vivo in humans, the structures that are actually indispensable to the function, by inducing a transient virtual lesion based on the inhibition of a subcircuit lasting a few seconds. Currently, this is the sole technique that is able to directly investigate the functional role of white matter tracts in humans. Thus, combining transient disturbances elicited by DES with the anatomical data provided by pre- and postoperative MRI enables to achieve reliable anatomo-functional correlations, supporting a network organization of the brain, and leading to the reappraisal of models of language representation. Finally, combining serial peri-operative functional neuroimaging and online intraoperative DES allows the study of mechanisms underlying neuroplasticity. This chapter critically reviews the basic principles of DES, its advantages and limitations, and what DES can reveal about the neural foundations of language, that is, the large-scale distribution of language areas in the brain, their connectivity, and their ability to reorganize.

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Optimizing Manufacturing and Osseointegration of Ti6Al4V Implants through Precision Casting and Calcium and Phosphorus Ion Implantation? In Vivo Results of a Large-Scale Animal Trial

Materials ◽

10.3390/ma13071670 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1670 ◽

Cited By ~ 2

Author(s):

Wölfle-Roos JV ◽

Katmer Amet B ◽

Fiedler J ◽

Michels H ◽

Kappelt G ◽

...

Keyword(s):

Ion Implantation ◽

Large Scale ◽

In Vivo Studies ◽

Control Group ◽

Implant Surface ◽

Precision Casting ◽

Pull Out ◽

Significant Difference ◽

Calcium And Phosphorus

Background: Uncemented implants are still associated with several major challenges, especially with regard to their manufacturing and their osseointegration. In this study, a novel manufacturing technique—an optimized form of precision casting—and a novel surface modification to promote osseointegration—calcium and phosphorus ion implantation into the implant surface—were tested in vivo. Methods: Cylindrical Ti6Al4V implants were inserted bilaterally into the tibia of 110 rats. We compared two generations of cast Ti6Al4V implants (CAST 1st GEN, n = 22, and CAST 2nd GEN, n = 22) as well as cast 2nd GEN Ti6Al4V implants with calcium (CAST + CA, n = 22) and phosphorus (CAST + P, n = 22) ion implantation to standard machined Ti6Al4V implants (control, n = 22). After 4 and 12 weeks, maximal pull-out force and bone-to-implant contact rate (BIC) were measured and compared between all five groups. Results: There was no significant difference between all five groups after 4 weeks or 12 weeks with regard to pull-out force (p > 0.05, Kruskal Wallis test). Histomorphometric analysis showed no significant difference of BIC after 4 weeks (p > 0.05, Kruskal–Wallis test), whereas there was a trend towards a higher BIC in the CAST + P group (54.8% ± 15.2%), especially compared to the control group (38.6% ± 12.8%) after 12 weeks (p = 0.053, Kruskal–Wallis test). Conclusion: In this study, we found no indication of inferiority of Ti6Al4V implants cast with the optimized centrifugal precision casting technique of the second generation compared to standard Ti6Al4V implants. As the employed manufacturing process holds considerable economic potential, mainly due to a significantly decreased material demand per implant by casting near net-shape instead of milling away most of the starting ingot, its application in manufacturing uncemented implants seems promising. However, no significant advantages of calcium or phosphorus ion implantation could be observed in this study. Due to the promising results of ion implantation in previous in vitro and in vivo studies, further in vivo studies with different ion implantation conditions should be considered.

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Evaluating Retinal and Choroidal Perfusion Changes after Isometric and Dynamic Activity Using Optical Coherence Tomography Angiography

Diagnostics ◽

10.3390/diagnostics11050808 ◽

2021 ◽

Vol 11 (5) ◽

pp. 808

Author(s):

Max Philipp Brinkmann ◽

Nikolas Xavier Kibele ◽

Michelle Prasuhn ◽

Vinodh Kakkassery ◽

Mario Damiano Toro ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Optical Coherence Tomography Angiography ◽

Isometric Exercise ◽

Dynamic Exercise ◽

Exercise Heart Rate ◽

Optical Coherence ◽

Dynamic Activity ◽

Capillary Plexus ◽

Choroidal Perfusion

Optical coherence tomography angiography (OCTA) is a non-invasive tool for imaging and quantifying the retinal and choroidal perfusion state in vivo. This study aimed to evaluate the acute effects of isometric and dynamic exercise on retinal and choroidal sublayer perfusion using OCTA. A pilot study was conducted on young, healthy participants, each of whom performed a specific isometric exercise on the first day and a dynamic exercise the day after. At baseline and immediately after the exercise, heart rate (HR), mean arterial pressure (MAP), superficial capillary plexus perfusion (SCPP), deep capillary plexus perfusion (DCPP), choriocapillaris perfusion (CCP), Sattlers’s layer perfusion (SLP), and Haller’s layer perfusion (HLP) were recorded. A total of 34 eyes of 34 subjects with a mean age of 32.35 ± 7.87 years were included. HR as well as MAP increased significantly after both types of exercise. Both SCPP and DCPP did not show any significant alteration due to isometric or dynamic exercise. After performing dynamic exercise, CCP, SLP, as well as HLP significantly increased. Changes in MAP correlated significantly with changes in HLP after the dynamic activity. OCTA-based analysis in healthy adults following physical activity demonstrated a constant retinal perfusion, supporting the theory of autoregulatory mechanisms. Dynamic exercise, as opposed to isometric activity, significantly changed choroidal perfusion. OCTA imaging may represent a novel and sensitive tool to expand the diagnostic spectrum in the field of sports medicine.

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Lentiviral Vectors for Delivery of Gene-Editing Systems Based on CRISPR/Cas: Current State and Perspectives

Viruses ◽

10.3390/v13071288 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1288

Author(s):

Wendy Dong ◽

Boris Kantor

Keyword(s):

Large Scale ◽

Lentiviral Vector ◽

Clinical Applications ◽

Scale Production ◽

Base Editing ◽

Epigenome Editing ◽

Vector Systems ◽

Dividing Cells

CRISPR/Cas technology has revolutionized the fields of the genome- and epigenome-editing by supplying unparalleled control over genomic sequences and expression. Lentiviral vector (LV) systems are one of the main delivery vehicles for the CRISPR/Cas systems due to (i) its ability to carry bulky and complex transgenes and (ii) sustain robust and long-term expression in a broad range of dividing and non-dividing cells in vitro and in vivo. It is thus reasonable that substantial effort has been allocated towards the development of the improved and optimized LV systems for effective and accurate gene-to-cell transfer of CRISPR/Cas tools. The main effort on that end has been put towards the improvement and optimization of the vector’s expression, development of integrase-deficient lentiviral vector (IDLV), aiming to minimize the risk of oncogenicity, toxicity, and pathogenicity, and enhancing manufacturing protocols for clinical applications required large-scale production. In this review, we will devote attention to (i) the basic biology of lentiviruses, and (ii) recent advances in the development of safer and more efficient CRISPR/Cas vector systems towards their use in preclinical and clinical applications. In addition, we will discuss in detail the recent progress in the repurposing of CRISPR/Cas systems related to base-editing and prime-editing applications.

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Transcriptional and morphological profiling of parvalbumin interneuron subpopulations in the mouse hippocampus

Nature Communications ◽

10.1038/s41467-020-20328-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Lin Que ◽

David Lukacsovich ◽

Wenshu Luo ◽

Csaba Földy

Keyword(s):

Large Scale ◽

Cell Types ◽

Rna Seq ◽

Neuronal Identity ◽

Parvalbumin Interneurons ◽

Different Types ◽

Parvalbumin Interneuron ◽

Cam Profile ◽

Developmental Domains

AbstractThe diversity reflected by >100 different neural cell types fundamentally contributes to brain function and a central idea is that neuronal identity can be inferred from genetic information. Recent large-scale transcriptomic assays seem to confirm this hypothesis, but a lack of morphological information has limited the identification of several known cell types. In this study, we used single-cell RNA-seq in morphologically identified parvalbumin interneurons (PV-INs), and studied their transcriptomic states in the morphological, physiological, and developmental domains. Overall, we find high transcriptomic similarity among PV-INs, with few genes showing divergent expression between morphologically different types. Furthermore, PV-INs show a uniform synaptic cell adhesion molecule (CAM) profile, suggesting that CAM expression in mature PV cells does not reflect wiring specificity after development. Together, our results suggest that while PV-INs differ in anatomy and in vivo activity, their continuous transcriptomic and homogenous biophysical landscapes are not predictive of these distinct identities.

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