Insect blood-brain barrier: an electrophysiological investigation of its permeability to the aliphatic alcohols

1976 ◽  
Vol 64 (1) ◽  
pp. 101-118
Author(s):  
M. V. Thomas
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Diffusion Barrier ◽  
Aliphatic Alcohols ◽  
Ionic Diffusion ◽  
Higher Alcohols ◽  
Electrophysiological Investigation ◽  
First Order ◽  
First Order Kinetics ◽  
Nerve Sheath

The anaesthetic effects of the aliphatic alcohols were used to measure their concentration at the neuronal surfaces of the cockroach central nervous system. The results were in most cases fairly closely described by first-order kinetics. The exchange half-times of the lower alcohols were only a few seconds, being little affected by the removal of the nerve sheath. The half-times for the higher alcohols were somewhat longer, and were more significantly reduced by desheathing; these observations were interpreted in terms of a reservoir effect resulting from their higher liposolubility. It was shown that the ionic diffusion barrier in intact nerve cords remained undamaged in the presence of the alcohols.

Glioblastoma and primary central nervous system lymphoma: differentiation using MRI derived first-order texture analysis – a machine learning study

2021 ◽  
pp. 197140092199897
Author(s):  
Sarv Priya ◽  
Caitlin Ward ◽  
Thomas Locke ◽  
Neetu Soni ◽  
Ravishankar Pillenahalli Maheshwarappa ◽  
...  
Keyword(s):  
Machine Learning ◽  
Central Nervous System ◽  
Nervous System ◽  
Diagnostic Performance ◽  
Model Performance ◽  
Area Under The Curve ◽  
Central Nervous System Lymphoma ◽  
First Order ◽  
Single Slice ◽  
Contrast Enhanced

Objectives To evaluate the diagnostic performance of multiple machine learning classifier models derived from first-order histogram texture parameters extracted from T1-weighted contrast-enhanced images in differentiating glioblastoma and primary central nervous system lymphoma. Methods Retrospective study with 97 glioblastoma and 46 primary central nervous system lymphoma patients. Thirty-six different combinations of classifier models and feature selection techniques were evaluated. Five-fold nested cross-validation was performed. Model performance was assessed for whole tumour and largest single slice using receiver operating characteristic curve. Results The cross-validated model performance was relatively similar for the top performing models for both whole tumour and largest single slice (area under the curve 0.909–0.924). However, there was a considerable difference between the worst performing model (logistic regression with full feature set, area under the curve 0.737) and the highest performing model for whole tumour (least absolute shrinkage and selection operator model with correlation filter, area under the curve 0.924). For single slice, the multilayer perceptron model with correlation filter had the highest performance (area under the curve 0.914). No significant difference was seen between the diagnostic performance of the top performing model for both whole tumour and largest single slice. Conclusions T1 contrast-enhanced derived first-order texture analysis can differentiate between glioblastoma and primary central nervous system lymphoma with good diagnostic performance. The machine learning performance can vary significantly depending on the model and feature selection methods. Largest single slice and whole tumour analysis show comparable diagnostic performance.

Sodium and Potassium Fluxes in the Abdominal Nerve Cord of the Cockroach, Periplaneta Americana L

1961 ◽  
Vol 38 (2) ◽  
pp. 315-322
Author(s):  
J. E. TREHERNE
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Periplaneta Americana ◽  
Unit Area ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Nerve Sheath ◽  
The Central Nervous System ◽  
Sodium And Potassium

1. The influx of sodium and potassium ions into the central nervous system of Periplaneta americana has been studied by measuring the increase in radioactivity within the abdominal nerve cord following the injection of 24NA and 42K. into the haemolymph. 2. The calculated influx of sodium ions was approximately 320 mM./l. of nerve cord water/hr. and of potassium ions was 312 mM./l. of nerve cord water/hr. These values are very approximately equivalent to an influx per unit area of nerve cord surface of 13.9 x 10-2 M cm. -2 sec.-1 for sodium and 13.5 x 10-12 M cm. -2 sec.-1 for potassium ions. 3. The relatively rapid influxes of these ions are discussed in relation to the postulated function of the nerve sheath as a diffusion barrier. It is suggested that a dynamic steady state rather than a static impermeability must exist across the sheath surrounding the central nervous system in this insect.

The Metabolism of Acetylcholine in the Intact Central Nervous System of An Insect (Periplaneta Americana L.)

1965 ◽  
Vol 43 (3) ◽  
pp. 441-454
Author(s):  
J. E. TREHERNE ◽  
D. S. SMITH
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Cholinergic System ◽  
Periplaneta Americana ◽  
Extracellular Fluid ◽  
Fibrous Layer ◽  
Nerve Sheath ◽  
The Central Nervous System ◽  
Hydrolysis Of

1. A very rapid metabolism of 3H-labelled acetylcholine has been demonstrated in the intact abdominal nerve cord. It has been shown that the cholinesterase system is effective in drastically reducing the concentration of acetylcholine in the extracellular fluid of the terminal abdominal ganglion with bathing solutions of up to IO-2M acetylcholine. 2. Evidence has been obtained which indicates that an appreciable hydrolysis of acetylcholine occurs at the periphery of the nerve cord. This effect is correlated with the electronmicroscopic demonstration of regions of eserine-sensitive cholinesterase located on glial membranes in the periphery of ganglia and connectives. It is suggested that some hydrolysis of extraneous acetylcholine may occur in the fibrous layer of the nerve sheath as a result of an accumulation of diffusible acetylcholinesterase in this region. 3. The results are discussed in relation to the possible involvement of the conventional cholinergic system in synaptic transmission in the central nervous system of this insect.

Meningial perineurioma: A benign peripheral nerve sheath tumor in a previously unrecognized central nervous system location, mimicking meningioma

2011 ◽  
Vol 207 (9) ◽  
pp. 592-596 ◽  
Author(s):  
Istvan Vajtai ◽  
Ekkehard Hewer ◽  
Robert Andres ◽  
Maja Neuenschwander ◽  
Andreas Kappeler ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Peripheral Nerve ◽  
Nerve Sheath Tumor ◽  
Peripheral Nerve Sheath Tumor ◽  
Nerve Sheath

scholarly journals Thoracic primary central nervous system melanoma and lumbar schwannoma of complex neurocristopathy: case report

2015 ◽  
Vol 23 (6) ◽  
pp. 780-783 ◽  
Author(s):  
Aaron Chance ◽  
Jesse J. Liu ◽  
Jeffrey S. Raskin ◽  
Viktor Zherebitskiy ◽  
Sakir H. Gultekin ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Case Report ◽  
Optic Nerve ◽  
Choroidal Melanoma ◽  
The Other ◽  
Pathological Findings ◽  
Nerve Sheath ◽  
Optic Nerve Sheath Meningioma ◽  
Sphenoid Wing Meningioma

Complex neurocristopathy, a disorder resulting from the aberrant proliferation of tissues derived from neural crest cells, has been previously reported in 2 patients, both involving ophthalmic melanoma and other tumors. One patient had a periorbital neurofibroma, sphenoid wing meningioma, and choroid juxtapapillary meningioma. The other patient had a choroidal melanoma and an optic nerve sheath meningioma. The authors describe clinical and pathological findings in a patient who underwent resection of 2 distinct lesions: primary CNS melanoma at T-12 and an L-5 schwannoma. Clinical and histopathological findings of the case are reviewed. To the authors’ knowledge, this is the first patient to present with complex neurocristopathy involving both a spinal melanoma and schwannoma.

Modeling the Evolution of a Soluble Matrix in Various Environments

1997 ◽  
Vol 506 ◽  
Author(s):  
S. Maillard ◽  
D. Iracane
Keyword(s):  
Experimental Investigation ◽  
Closed Form ◽  
Diffusion Barrier ◽  
Length Scales ◽  
First Order ◽  
First Order Kinetics ◽  
Clay Barrier

ABSTRACTWe model the dissolution of a soluble matrix protected by a diffusion barrier. The dissolution, driven by a first order kinetics law, allows the solute to diffuse in the barrier with sorption and precipitation interactions. The dissolved mass evolution and the lifetime of the wasteform can be expressed in a closed form and as a function of relevant length scales, reflecting the phenomenon controlling the dissolution. Application to a nuclear glass in a clay barrier shows that diffusion in the barrier is the main phenomenon unless precipitation of chalcedony occurs or silicon is very strongly sorbed in the barrier. This requires further experimental investigation of silicon/clay interaction.

Lifetimes of the solvated electron in liquid alcohols

1977 ◽  
Vol 55 (16) ◽  
pp. 3058-3059 ◽  
Author(s):  
J. H. Baxendale ◽  
Peter Wardman
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Aliphatic Alcohols ◽  
Solvated Electron ◽  
Arrhenius Plots ◽  
First Order ◽  
First Order Kinetics

The solvated electron, es−, decays with first-order kinetics in pulse-irradiated aliphatic alcohols, attributed to reaction 1: es− + ROH → products. It is suggested that a recent report of curved Arrhenius plots for the temperature dependence of the rate constants for reaction 1 can be ascribed to reaction of es− with impurities.

Sign in / Sign up

Export Citation Format

Share Document