Cerebral Tissue Response in Chronic Electrode Implantation

1977 ◽  
Vol 35 ◽  
pp. 624-625
Author(s):  
R.F. Dodson ◽  
L.W-F Chu ◽  
N. Ishihara
Keyword(s):  
Tissue Response ◽  
Whole Body ◽  
Platinum Electrodes ◽  
Fixed Tissue ◽  
Electrode Implantation ◽  
Surface Areas ◽  
Tissue Changes ◽  
Micron Diameter ◽  
Extent Of Damage ◽  
Electrode Sheath

The extent of damage surrounding an implanted electrode in the cerebral cortex is a question of significant importance with regard to attaining consistency and validity of physiological recordings. In order to determine the extent of such tissue changes, 150 micron diameter platinum electrodes were implanted in the cortex of four adult baboons, and after eight days the animals were sacrificed by whole body perfusion with a 3% glutaraldehyde in 0.1M phosphate fixative.The calvarium was carefully removed and the electrode tracts were readily discernible in the firm, glutaraldehyde fixed tissue.Careful dissection of the zone of the electrode tract resulted in a small block which was further sectioned into tip, mid-tract and surface areas. Ultrastructurally, damage extended from the electrode sheath to the greatest extent of from 0.2 to 3.5 mm.

scholarly journals Cerebral Tissue Response to Electrode Implantation

1978 ◽  
Vol 5 (4) ◽  
pp. 443-446 ◽  
Author(s):  
Ronald F. Dodson ◽  
L.W-F Chu ◽  
N. Ishihara
Keyword(s):  
White Matter ◽  
Subcortical White Matter ◽  
Tissue Response ◽  
Platinum Electrodes ◽  
Cerebral Tissue ◽  
Electrode Implantation ◽  
Cortical Areas ◽  
Cortical Gray Matter ◽  
Tissue Alterations ◽  
Implantation Period

SUMMARY:Tissue response to platinum electrodes was assessed after an eight-day implantation period. The regions of study included the cortical areas at the opercular gyri and at the sulcus parielo-occipitalis externus, as well as the sub-cortical white matter in these areas.Perivascular and intraparenchymal hemorrhagic lesions as well as edematous changes characterized both by extensive intra and extracellular swelling were noted. Numerous phagocytic elements and degenerative structures were present at the electrode I parenchymal interface.Tissue alterations were asymmetrical as observed both around and at the lip of the implanted electrode. The parenchymal alterations extended from 0.2mm to 3.5mm distance from the electrode path/ parenchymal interface.Greater tissue involvement was found in the subcortical white matter as compared to the adjacent cortical gray matter.

Evaluation of Fibrin Sealants for Central Nervous System Sealing in the Mongrel Dog Durotomy Model

Neurosurgery ◽  
2011 ◽  
Vol 69 (4) ◽  
pp. 921-929 ◽  
Author(s):  
Richard W Hutchinson ◽  
Vince Mendenhall ◽  
Randolph M Abutin ◽  
Tim Muench ◽  
James Hart
Keyword(s):  
Fibrin Sealant ◽  
Tissue Response ◽  
Neurosurgical Procedures ◽  
Fibrin Sealants ◽  
Csf Leakage ◽  
Mongrel Dog ◽  
Tissue Changes ◽  
Foamy Macrophages ◽  
The Brain

Abstract BACKGROUND: Watertight repair of the dura is imperative after neurosurgical procedures involving the brain or spinal cord because inadequately treated leakage of cerebrospinal fluid (CSF) from punctured dura can have serious consequences such as meningitis, arachnoiditis, or epidural abscess. OBJECTIVE: To assess the efficacy of Evicel Fibrin Sealant (Human) to prevent CSF leakage using a 2.0-cm durotomy mongrel dog repair model and to compare the tissue response with Tisseel (a fibrin sealant) and Duraseal (a synthetic polyethylene glycol [PEG] hydrogel sealant). METHODS: The canine durotomy repair model was used. This well-characterized model assesses the ability of sealants to achieve intraoperative watertight seals of the dura mater, as well as long-term safety and efficacy. This study included 27 mongrel dogs and had a 28-day duration. RESULTS: The 3 sealants were 100% effective in preventing CSF leakage intraoperatively at 15 mm Hg. The 2 fibrin sealants were 100% effective in postoperative sealing; the PEG hydrogel was not. Microscopically, the tissue changes induced by Evicel at the durotomy site were similar in nature except for foamy macrophages seen only with the PEG hydrogel. The extent and severity of adhesions at 28 days were less with the fibrin sealants than with the PEG hydrogel. CONCLUSION: Evicel, a fibrin sealant, was safe and effective in achieving and maintaining a watertight seal of the dura. The performance of the fibrin sealants was similar to that of the synthetic PEG hydrogel sealant with the exception of a Duraseal seal, which leaked.

THE ELECTRODE BEHAVIOR OF PLATINUM

1953 ◽  
Vol 31 (7) ◽  
pp. 665-672
Author(s):  
A. K. Wiebe ◽  
C. A. Winkler
Keyword(s):  
Sulphuric Acid ◽  
Saturated Calomel Electrode ◽  
Platinum Electrodes ◽  
Platinum Surface ◽  
Surface Areas ◽  
The Times

A potential of −0.305 ± 0.005 volt (relative to a saturated calomel electrode) was obtained at a freshly prepared platinum surface within 30 sec. of immersion in oxygen-free N/5 sulphuric acid saturated with hydrogen. In electrolytes saturated with nitrogen or oxygen potentials of +0.05 ± 0.01 volt and +0.745 ± 0.005 volt respectively were more slowly attained. The times required for the electrode to reach maximum potentials, tmax, when it was made a cathode, and corresponding values of tmax when it was rendered anodic, were determined over a range of currents. The values of tmax appear to provide a method of determining the surface areas of platinum electrodes.

THE USE OF SMALL SKIN SURFACE AREAS FOR WHOLE BODY SWEATING ASSESSMENT

1965 ◽  
Vol 43 (6) ◽  
pp. 971-977 ◽  
Author(s):  
Arthur C. Custance
Keyword(s):  
Body Weight ◽  
Body Weight Loss ◽  
Total Body Weight ◽  
Skin Surface ◽  
Moisture Loss ◽  
Whole Body ◽  
Surface Areas ◽  
Short Period ◽  
The Subject ◽  
Total Body

It is possible to obtain a continuous record of the sweating rate of an active subject by monitoring changes in total body weight. However, elaborate equipment is required that is capable of accommodating the treadmill (or other exercising device) as well as the subject. The balance must be rugged enough to withstand the movements of the subject, yet sensitive enough to respond to small changes in weight. It would be a great convenience to be able, instead, to monitor small representative areas of the skin surface with confidence that they faithfully reflect whole body reactions.In this research, moisture loss from a representative area of the skin of the dorsum under a capsule covering 14 sq. cm was measured by an apparatus which automatically altered the flow of dry air to keep the humidity of the effluent constant. In four subjects exercising on a treadmill at 3.5 m.p.h. the correlation coefficient between the area under the curves so obtained and the total body weight loss was very high (more than 0.93), and there was also good correlation after sweating was partially suppressed by atropine. Short-period fluctuations were simultaneous and highly correlated between bilaterally symmetrical areas of skin. It is concluded that moisture loss from a single area of skin can be used to represent changes in the rate and pattern of sweating of the whole body.

scholarly journals Minimal Tissue Reaction after Chronic Subdural Electrode Implantation for Fully Implantable Brain–Machine Interfaces

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 178
Author(s):  
Tianfang Yan ◽  
Seiji Kameda ◽  
Katsuyoshi Suzuki ◽  
Taro Kaiju ◽  
Masato Inoue ◽  
...  
Keyword(s):  
Tissue Reaction ◽  
Tissue Response ◽  
Brain Machine Interfaces ◽  
Electrode Implantation ◽  
Subdural Electrodes ◽  
Tissue Proliferation ◽  
Significant Difference ◽  
Subdural Electrode ◽  
Cell Densities

There is a growing interest in the use of electrocorticographic (ECoG) signals in brain–machine interfaces (BMIs). However, there is still a lack of studies involving the long-term evaluation of the tissue response related to electrode implantation. Here, we investigated biocompatibility, including chronic tissue response to subdural electrodes and a fully implantable wireless BMI device. We implanted a half-sized fully implantable device with subdural electrodes in six beagles for 6 months. Histological analysis of the surrounding tissues, including the dural membrane and cortices, was performed to evaluate the effects of chronic implantation. Our results showed no adverse events, including infectious signs, throughout the 6-month implantation period. Thick connective tissue proliferation was found in the surrounding tissues in the epidural space and subcutaneous space. Quantitative measures of subdural reactive tissues showed minimal encapsulation between the electrodes and the underlying cortex. Immunohistochemical evaluation showed no significant difference in the cell densities of neurons, astrocytes, and microglia between the implanted sites and contralateral sites. In conclusion, we established a beagle model to evaluate cortical implantable devices. We confirmed that a fully implantable wireless device and subdural electrodes could be stably maintained with sufficient biocompatibility in vivo.

scholarly journals Electrochemical characteristics of nanostructured platinum electrodes – a cyclic voltammetry study

2014 ◽  
Vol 16 (18) ◽  
pp. 8392-8399 ◽  
Author(s):  
P. Daubinger ◽  
J. Kieninger ◽  
T. Unmüssig ◽  
G. A. Urban
Keyword(s):  
Cyclic Voltammetry ◽  
Active Surface ◽  
Electrochemical Characteristics ◽  
Platinum Electrodes ◽  
Surface Areas ◽  
Electrochemically Active ◽  
Electrochemical Phenomena ◽  
Electrochemically Active Surface

This article describes the electrochemical phenomena occurring at nanostructured platinum electrodes with high electrochemically active surface areas.

scholarly journals MRI based physiological parameters are biomarkers of tumor and non tumor tissue response following radiation to brain metastases

2021 ◽  
Author(s):  
Raphael Y Jakubovic
Keyword(s):  
Brain Metastases ◽  
Tissue Response ◽  
Dynamic Susceptibility ◽  
Dose Planning ◽  
Contrast Enhanced ◽  
Tissue Changes ◽  
Pre Treatment ◽  
Time Specific ◽  
Relative Blood Volume ◽  
Planning Ct

We sought to determine the utility of early relative blood volume (rCBV), relative blood flow (rCBF) and permeability (K2 trans) measurements as biomarkers of radiation response or progression for brain metastases and to characterize early normal tissue changes following stereotactic radiosurgery. Patients were imaged with dynamic susceptibility and dynamic contrast enhanced magnetic resonance imaging at baseline, 1 week and 1 month post-treatment. Tumors outcomes were stratified using volumetric data obtained from structural images. K2trans at 1 week and rCBV at 1 month were identified as predictors of tumor response and progressive disease respectively. Pre-treatment localized dose planning CT images with overlaid isodose distributions outside the tumor were evaluated within all tissue, and segmented gray and white matter. rCBV and rCBF ratio differences between baseline, 1 week and 1 month were compared. Subsequent analysis identified increases in rCBF and rCBV ratios occurring in a dose, tissue, and time specific manner.

scholarly journals Chronically Implanted Intracranial Electrodes: Tissue Reaction and Electrical Changes

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 430 ◽  
Author(s):  
Andrew Campbell ◽  
Chengyuan Wu
Keyword(s):  
Tissue Reaction ◽  
Tissue Response ◽  
Significant Progress ◽  
Electrode Implantation ◽  
Disease States ◽  
Electrode Interface ◽  
Intracranial Electrodes ◽  
Electrode Systems ◽  
The Brain ◽  
Made In

The brain-electrode interface is arguably one of the most important areas of study in neuroscience today. A stronger foundation in this topic will allow us to probe the architecture of the brain in unprecedented functional detail and augment our ability to intervene in disease states. Over many years, significant progress has been made in this field, but some obstacles have remained elusive—notably preventing glial encapsulation and electrode degradation. In this review, we discuss the tissue response to electrode implantation on acute and chronic timescales, the electrical changes that occur in electrode systems over time, and strategies that are being investigated in order to minimize the tissue response to implantation and maximize functional electrode longevity. We also highlight the current and future clinical applications and relevance of electrode technology.

scholarly journals MRI based physiological parameters are biomarkers of tumor and non tumor tissue response following radiation to brain metastases

2021 ◽  
Author(s):  
Raphael Y Jakubovic
Keyword(s):  
Brain Metastases ◽  
Tissue Response ◽  
Dynamic Susceptibility ◽  
Dose Planning ◽  
Contrast Enhanced ◽  
Tissue Changes ◽  
Pre Treatment ◽  
Time Specific ◽  
Relative Blood Volume ◽  
Planning Ct

We sought to determine the utility of early relative blood volume (rCBV), relative blood flow (rCBF) and permeability (K2 trans) measurements as biomarkers of radiation response or progression for brain metastases and to characterize early normal tissue changes following stereotactic radiosurgery. Patients were imaged with dynamic susceptibility and dynamic contrast enhanced magnetic resonance imaging at baseline, 1 week and 1 month post-treatment. Tumors outcomes were stratified using volumetric data obtained from structural images. K2trans at 1 week and rCBV at 1 month were identified as predictors of tumor response and progressive disease respectively. Pre-treatment localized dose planning CT images with overlaid isodose distributions outside the tumor were evaluated within all tissue, and segmented gray and white matter. rCBV and rCBF ratio differences between baseline, 1 week and 1 month were compared. Subsequent analysis identified increases in rCBF and rCBV ratios occurring in a dose, tissue, and time specific manner.

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