scholarly journals Cultured Neural Networks: Optimization of Patterned Network Adhesiveness and Characterization of their Neural Activity

2006 ◽  
Vol 3 (1) ◽  
pp. 1-7 ◽  
Author(s):  
W. L. C. Rutten ◽  
T. G. Ruardij ◽  
E. Marani ◽  
B. H. Roelofsen
Keyword(s):  
Neural Activity ◽  
Microelectrode Array ◽  
Electrode Site ◽  
Local Networks ◽  
Planar Substrate ◽  
Neural Information ◽  
Neural Networks Optimization ◽  
High Degree

One type of future, improved neural interface is the “cultured probe”. It is a hybrid type of neural information transducer or prosthesis, for stimulation and/or recording of neural activity. It would consist of a microelectrode array (MEA) on a planar substrate, each electrode being covered and surrounded by a local circularly confined network (“island”) of cultured neurons. The main purpose of the local networks is that they act as biofriendly intermediates for collateral sprouts from thein vivosystem, thus allowing for an effective and selective neuron–electrode interface. As a secondary purpose, one may envisage future information processing applications of these intermediary networks. In this paper, first, progress is shown on how substrates can be chemically modified to confine developing networks, cultured from dissociated rat cortex cells, to “islands” surrounding an electrode site. Additional coating of neurophobic, polyimide-coated substrate by triblock-copolymer coating enhances neurophilic-neurophobic adhesion contrast. Secondly, results are given on neuronal activity in patterned, unconnected and connected, circular “island” networks. For connected islands, the larger the island diameter (50, 100 or 150 μm), the more spontaneous activity is seen. Also, activity may show a very high degree of synchronization between two islands. For unconnected islands, activity may start at 22 days in vitro (DIV), which is two weeks later than in unpatterned networks.

scholarly journals In Vivo Dopamine Detection and Single Unit Recordings Using Intracortical Glassy Carbon Microelectrode Arrays

MRS Advances ◽  
2018 ◽  
Vol 3 (29) ◽  
pp. 1629-1634 ◽  
Author(s):  
Elisa Castagnola ◽  
Nasim Winchester Vahidi ◽  
Surabhi Nimbalkar ◽  
Srihita Rudraraju ◽  
Marvin Thielk ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Neural Activity ◽  
Microelectrode Array ◽  
Flexible Substrate ◽  
Microelectrode Arrays ◽  
European Starling ◽  
Dopamine Detection ◽  
Vertical Spacing

ABSTRACTIn this study, we present a 4-channel intracortical glassy carbon (GC) microelectrode array on a flexible substrate for the simultaneous in vivo neural activity recording and dopamine (DA) concentration measurement at four different brain locations (220µm vertical spacing). The ability of GC microelectrodes to detect DA was firstly assessed in vitro in phosphate-buffered saline solution and then validated in vivo measuring spontaneous DA concentration in the Striatum of European Starling songbird through fast scan cyclic voltammetry(FSCV). The capability of GC microelectrode arrays and commercial penetrating metal microelectrode arrays to record neural activity from the Caudomedial Neostriatum of European starling songbird was compared. Preliminary results demonstrated the ability of GC microelectrodes in detecting neurotransmitters release and recording neural activity in vivo. GC microelectrodes array may, therefore, offer a new opportunity to understand the intimate relations linking electrophysiological parameters with neurotransmitters release.

scholarly journals On the origin of the increased tissue iron content in graded magnesium deficiency states in the rat

1997 ◽  
Vol 77 (3) ◽  
pp. 475-490 ◽  
Author(s):  
Klaus Schumann ◽  
Annette Lebeau ◽  
Ursula Gresser ◽  
Theodor Gunther ◽  
Jürgen Vormann
Keyword(s):  
Haemolytic Anaemia ◽  
Rapid Growth ◽  
Magnesium Deficiency ◽  
Erythropoietic Activity ◽  
Mg Deficiency ◽  
Adequate Diet ◽  
Fe Content ◽  
High Degree

To investigate the mechanism of tissue Fe accumulation in graded Mg deficiency rats were fed on diets of different Mg contents (70, 110, 208, 330, and 850 mg Mg/kg) for 10, 20, and 30 d during rapid growth. There was no significant impact of Mg deficiency or high luminal Mg concentrations on intestinal59Fe transferin vitroorin vivo. Plasma Mg concentrations and body weight started to decrease after 10 d. Significant haemolytic anaemia was observed after 20 d with siderosis in liver and spleen developing in parallel. Anaemia showed no features of Fe deficiency or infiammation. Comparison between the 70 mg Mg/kg group and animals that received the same quantity of a Mg-adequate diet (850 mg Mg/kg) permitted estimation of quantities of Fe liberated by haemolysis and the increased Fe content in liver and spleen. Both variables showed a high degree of correlation, indicating that the excess of liberated haemoglobin Fe was stored in the tissue. The erythropoietic activity was high during rapid growth, i.e. at days 10 and 20 and decreased significantly after 30 d in all except the most Mg-deficient groups. However, haemolytic anaemia developed because even the high erythropoietic activity in the 70 and 110 mg Mg/kg groups was not sutlicient to recycle all haemoglobin Fe liberated by haemolysis. After 30 d of Mg-deficient feeding the erythrocyte Mg content had decreased to 40% of control values. According to the literature Mg-deficient erythrocytes have a decreased survival time which is likely to be the cause of the observed haemolysis.

Developmental regulation of heterochromatin-mediated gene silencing in Drosophila

Development ◽  
1998 ◽  
Vol 125 (12) ◽  
pp. 2223-2234 ◽  
Author(s):  
B.Y. Lu ◽  
J. Ma ◽  
J.C. Eissenberg
Keyword(s):  
Cell Cycle ◽  
Gene Silencing ◽  
Mitotic Activity ◽  
Larval Stage ◽  
Developmental Regulation ◽  
Promoter Strength ◽  
Lacz Gene ◽  
High Degree

The roles of differentiation, mitotic activity and intrinsic promoter strength in the maintenance of heterochromatic silencing were investigated during development using an inducible lacZ gene as an in vivo probe. Heterochromatic silencing is initiated at the onset of gastrulation, approximately 1 hour after heterochromatin is first visible cytologically. A high degree of silencing is maintained in the mitotically active imaginal cells from mid-embryogenesis until early third instar larval stage, and extensive relaxation of silencing is tightly associated with the onset of differentiation. Relaxation of silencing can be triggered in vitro by ecdysone. In contrast, timing and extent of silencing at both the initiation and relaxation stages are insensitive to changes in cell cycle activity, and intrinsic promoter strength also does not influence the extent of silencing by heterochromatin. These data suggest that the silencing activity of heterochromatin is developmentally programmed.

scholarly journals Isolation and characterization of adrenocortical progenitors involved in the adaptation to stress

2018 ◽  
Vol 115 (51) ◽  
pp. 12997-13002 ◽  
Author(s):  
Charlotte Steenblock ◽  
Maria F. Rubin de Celis ◽  
Luis F. Delgadillo Silva ◽  
Verena Pawolski ◽  
Ana Brennand ◽  
...  
Keyword(s):  
Lineage Tracing ◽  
Differentiated Cells ◽  
Isolation And Characterization ◽  
Proliferation And Differentiation ◽  
Response To Stress ◽  
Steroidogenic Cells ◽  
High Degree

The adrenal gland is a master regulator of the human body during response to stress. This organ shows constant replacement of senescent cells by newly differentiated cells. A high degree of plasticity is critical to sustain homeostasis under different physiological demands. This is achieved in part through proliferation and differentiation of adult adrenal progenitors. Here, we report the isolation and characterization of a Nestin+ population of adrenocortical progenitors located under the adrenal capsule and scattered throughout the cortex. These cells are interconnected with progenitors in the medulla. In vivo lineage tracing revealed that, under basal conditions, this population is noncommitted and slowly migrates centripetally. Under stress, this migration is greatly enhanced, and the cells differentiate into steroidogenic cells. Nestin+ cells cultured in vitro also show multipotency, as they differentiate into mineralocorticoid and glucocorticoid-producing cells, which can be further influenced by the exposure to Angiotensin II, adrenocorticotropic hormone, and the agonist of luteinizing hormone-releasing hormone, triptorelin. Taken together, Nestin+ cells in the adult adrenal cortex exhibit the features of adrenocortical progenitor cells. Our study provides evidence for a role of Nestin+ cells in organ homeostasis and emphasizes their role under stress. This cell population might be a potential source of cell replacement for the treatment of adrenal insufficiency.

scholarly journals Transcriptomic-Based Quantification of the Epithelial-Hybrid-Mesenchymal Spectrum Across Biological Contexts

Biomolecules ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Susmita Mandal ◽  
Tanishq Tejaswi ◽  
Rohini Janivara ◽  
Syamanthak Srikrishnan ◽  
Pradipti Thakur ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Cancer Metastasis ◽  
Expression Profiles ◽  
Gene List ◽  
Cellular Reprogramming ◽  
Induced Pluripotent ◽  
Patient Prognosis ◽  
High Degree

Epithelial-mesenchymal plasticity (EMP) underlies embryonic development, wound healing, and cancer metastasis and fibrosis. Cancer cells exhibiting EMP often have more aggressive behavior, characterized by drug resistance, and tumor-initiating and immuno-evasive traits. Thus, the EMP status of cancer cells can be a critical indicator of patient prognosis. Here, we compare three distinct transcriptomic-based metrics—each derived using a different gene list and algorithm—that quantify the EMP spectrum. Our results for over 80 cancer-related RNA-seq datasets reveal a high degree of concordance among these metrics in quantifying the extent of EMP. Moreover, each metric, despite being trained on cancer expression profiles, recapitulates the expected changes in EMP scores for non-cancer contexts such as lung fibrosis and cellular reprogramming into induced pluripotent stem cells. Thus, we offer a scoring platform to quantify the extent of EMP in vitro and in vivo for diverse biological applications including cancer.

Ex Vivo Brain Preparation to Analyze Vocal Pathways of Xenopus Frogs

2021 ◽  
Vol 2021 (9) ◽  
pp. pdb.prot106872
Author(s):  
Ayako Yamaguchi
Keyword(s):  
Neural Activity ◽  
Ex Vivo ◽  
Neural Circuitry ◽  
Neural Basis ◽  
Vocal Production ◽  
Basic Principles ◽  
Electrophysiological Recordings ◽  
The Brain

Understanding the neural basis of behavior is a challenging task for technical reasons. Most methods of recording neural activity require animals to be immobilized, but neural activity associated with most behavior cannot be recorded from an anesthetized, immobilized animal. Using amphibians, however, there has been some success in developing in vitro brain preparations that can be used for electrophysiological and anatomical studies. Here, we describe an ex vivo frog brain preparation from which fictive vocalizations (the neural activity that would have produced vocalizations had the brain been attached to the muscle) can be elicited repeatedly. When serotonin is applied to the isolated brains of male and female African clawed frogs, Xenopus laevis, laryngeal nerve activity that is a facsimile of those that underlie sex-specific vocalizations in vivo can be readily recorded. Recently, this preparation was successfully used in other species within the genus including Xenopus tropicalis and Xenopus victorianus. This preparation allows a variety of techniques to be applied including extracellular and intracellular electrophysiological recordings and calcium imaging during vocal production, surgical and pharmacological manipulation of neurons to evaluate their impact on motor output, and tract tracing of the neural circuitry. Thus, the preparation is a powerful tool with which to understand the basic principles that govern the production of coherent and robust motor programs in vertebrates.

scholarly journals Increased Carrier Peptide Stability through pH Adjustment Improves Insulin and PTH(1-34) Delivery In Vitro and In Vivo Rather than by Enforced Carrier Peptide-Cargo Complexation

Pharmaceutics ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 993
Author(s):  
Mie Kristensen ◽  
Ragna Guldsmed Diedrichsen ◽  
Valeria Vetri ◽  
Vito Foderà ◽  
Hanne Mørck Nielsen
Keyword(s):  
Oral Delivery ◽  
Molecular Size ◽  
Therapeutic Peptide ◽  
Enzymatic Stability ◽  
Therapeutic Peptides ◽  
Ph Dependent ◽  
Pharmacologically Active ◽  
High Degree

Oral delivery of therapeutic peptides is hampered by their large molecular size and labile nature, thus limiting their permeation across the intestinal epithelium. Promising approaches to overcome the latter include co-administration with carrier peptides. In this study, the cell-penetrating peptide penetratin was employed to investigate effects of co-administration with insulin and the pharmacologically active part of parathyroid hormone (PTH(1-34)) at pH 5, 6.5, and 7.4 with respect to complexation, enzymatic stability, and transepithelial permeation of the therapeutic peptide in vitro and in vivo. Complex formation between insulin or PTH(1-34) and penetratin was pH-dependent. Micron-sized complexes dominated in the samples prepared at pH-values at which penetratin interacts electrostatically with the therapeutic peptide. The association efficiency was more pronounced between insulin and penetratin than between PTH(1-34) and penetratin. Despite the high degree of complexation, penetratin retained its membrane activity when applied to liposomal structures. The enzymatic stability of penetratin during incubation on polarized Caco-2 cell monolayers was pH-dependent with a prolonged half-live determined at pH 5 when compared to pH 6.5 and 7.4. Also, the penetratin-mediated transepithelial permeation of insulin and PTH(1-34) was increased in vitro and in vivo upon lowering the sample pH from 7.4 or 6.5 to 5. Thus, the formation of penetratin-cargo complexes with several molecular entities is not prerequisite for penetratin-mediated transepithelial permeation a therapeutic peptide. Rather, a sample pH, which improves the penetratin stability, appears to optimize the penetratin-mediated transepithelial permeation of insulin and PTH(1-34).

Ultrasound-Mediated Drug Delivery in Cancer Therapy: A Review

2020 ◽  
Vol 20 (12) ◽  
pp. 7211-7230 ◽  
Author(s):  
Nour M. Al Sawaftah ◽  
Ghaleb A. Husseini
Keyword(s):  
Drug Delivery ◽  
Targeted Drug Delivery ◽  
Controlled Drug Release ◽  
Medical Applications ◽  
Adverse Side Effects ◽  
Medical Diagnostic ◽  
High Degree ◽  
Ultrasound Parameters

The use of ultrasound as a medical diagnostic tool began in the 1940s. Ever since, the medical applications of ultrasound have included imaging, tumor ablation, and lithotripsy; however, an ever-increasing body of literature demonstrates that ultrasound has potential in other medical applications, including targeted drug delivery. Site-specific drug delivery involves delivering drugs to diseased areas with a high degree of precision, which is particularly advantageous in cancer treatment as it would minimize the adverse side effects experienced by patients. This review addresses the ability of ultrasound to induce localized and controlled drug release from nanocarriers, namely micelles and liposomes, utilizing thermal and/or mechanical effects. The interactions of ultrasound with micelles and liposomes, the effects of the lipid composition, and ultrasound parameters on the release of encapsulated drugs are discussed. In addition, a survey of the literature detailing some in vitro and in vivo ultrasound triggered drug delivery systems is presented.

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