scholarly journals Improving Deep Brain Stimulation Electrode Performance in vivo Through Use of Conductive Hydrogel Coatings

2021 ◽  
Vol 15 ◽  
Author(s):  
Tomoko Hyakumura ◽  
Ulises Aregueta-Robles ◽  
Wenlu Duan ◽  
Joel Villalobos ◽  
Wendy K. Adams ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Tissue Response ◽  
Platinum Electrodes ◽  
Electrode Arrays ◽  
Compulsive Disorder ◽  
Charge Densities ◽  
Significant Difference ◽  
Neural Survival ◽  
Deep Brain

Active implantable neurological devices like deep brain stimulators have been used over the past few decades to treat movement disorders such as those in people with Parkinson’s disease and more recently, in psychiatric conditions like obsessive compulsive disorder. Electrode-tissue interfaces that support safe and effective targeting of specific brain regions are critical to success of these devices. Development of directional electrodes that activate smaller volumes of brain tissue requires electrodes to operate safely with higher charge densities. Coatings such as conductive hydrogels (CHs) provide lower impedances and higher charge injection limits (CILs) than standard platinum electrodes and support safer application of smaller electrode sizes. The aim of this study was to examine the chronic in vivo performance of a new low swelling CH coating that supports higher safe charge densities than traditional platinum electrodes. A range of hydrogel blends were engineered and their swelling and electrical performance compared. Electrochemical performance and stability of high and low swelling formulations were compared during insertion into a model brain in vitro and the formulation with lower swelling characteristics was chosen for the in vivo study. CH-coated or uncoated Pt electrode arrays were implanted into the brains of 14 rats, and their electrochemical performance was tested weekly for 8 weeks. Tissue response and neural survival was assessed histologically following electrode array removal. CH coating resulted in significantly lower voltage transient impedance, higher CIL, lower electrochemical impedance spectroscopy, and higher charge storage capacity compared to uncoated Pt electrodes in vivo, and this advantage was maintained over the 8-week implantation. There was no significant difference in evoked potential thresholds, signal-to-noise ratio, tissue response or neural survival between CH-coated and uncoated Pt groups. The significant electrochemical advantage and stability of CH coating in the brain supports the suitability of this coating technology for future development of smaller, higher fidelity electrode arrays with higher charge density requirement.

scholarly journals The Dynamics of Subcutaneous Tissue Response to Microorganisms Associated with the Extract of Araçá (Psidium cattleianum): An Edemogenic and Microscopic Analysis

2017 ◽  
Vol 20 (2) ◽  
pp. 93 ◽  
Author(s):  
Alessandra Cury Machado ◽  
Denise Belucio Ruviere ◽  
Renata Zoccal Novais ◽  
Carlos Roberto Emerenciano Bueno ◽  
Elerson Gaetti Jardim Jr ◽  
...  
Keyword(s):  
Subcutaneous Tissue ◽  
Tissue Response ◽  
Male Rats ◽  
Saline Control ◽  
Control Group ◽  
Dorsal Region ◽  
Hydroalcoholic Extract ◽  
Psidium Cattleianum ◽  
Significant Difference

<p><strong>Objective:</strong> To evaluate <em>in vivo </em>tissue reaction to the extract of araçá (<em>Psidium cattleianum</em>) associated with inactivated microorganisms. <strong>Material and Methods:</strong> A 0.1 mL suspension was used containing Porphyromonas gingivalis, Prevotella intermedia, <em>Fusobacterium nucleatum, Enterococcus faecalis, Peptostreptococcus micros</em>, and <em>Porphyromonas endodontalis,</em> which were inactivated by heat and mixed into a 1.0 mL saline (control group), an aqueous solution, or a hydroalcoholic extract of araçá. Eighteen male rats (<em>Rattus norvegiccus</em>) under general anesthesia received 0.2 mL of 1% intravenous Evans blue. Thirty minutes later, 0.1 mL of one of the associations was injected into the animals’ dorsal region. The animals were euthanized after 3 and 6 hours, and the materials obtained were placed in formamide for 72 hours then analyzed in a spectrophotometer (λ=630 hm). For the morphological analysis, 30 rats received polyethylene tubes implants with the extracts or the saline with the associations in the dorsal region and euthanized after 7 and 30 days to be analyzed according to an inflammation cell score. <strong>Results:</strong> No significant difference (p&gt;0.05) was observed in the edema among groups. The optical microscopy results showed a repair in the 30-day-period, which was higher when compared to the 7-day-period (p&lt;0.0001). Nevertheless, in the 7-day-period, the hydroalcoholic extract presented a significant response compared to the aqueous extract (p=0.05) and a trend for better results than the control group. <strong>Conclusion: </strong>The aqueous and hydroalcoholic araçá extracts associated with inactivated microorganisms showed similar responses to control, indicating no interference on the toxic effects of the bacterial components in tissue repair.</p><p><strong>Keywords</strong></p><p>Anaerobic bacteria; Edema; Inflammation; Plant extracts; <em>Psidium.</em></p>

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 Physical Properties, Antimicrobial Activity and In Vivo Tissue Response to Apexit Plus

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1171 ◽  
Author(s):  
Roberto Alameda Hoshino ◽  
Guilherme Ferreira da Silva ◽  
Mateus Machado Delfino ◽  
Juliane Maria Guerreiro-Tanomaru ◽  
Mario Tanomaru-Filho ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Physical Properties ◽  
Enterococcus Faecalis ◽  
Subcutaneous Tissue ◽  
Setting Time ◽  
Tissue Reaction ◽  
Tissue Response ◽  
Control Group ◽  
Significant Difference

We investigated the physical properties, antimicrobial activity, and tissue reaction to Apexit Plus in comparison to Sealapex. Flow, radiopacity, setting time, and solubility were evaluated in each material. The antimicrobial activity against Enterococcus faecalis was performed. Polyethylene tubes containing Apexit Plus or Sealapex, and without material (control group) were implanted into the subcutaneous tissue of rats. At 7, 15, 30, and 60 days of implantation, the specimens were paraffin-embedded and the number of inflammatory cells (ICs) and the amount of birefringent collagen (BC) were quantified. The von Kossa reaction followed by immunohistochemistry for detection of alkaline phosphatase (ALP) was also performed. Statistical analysis was performed with ANOVA and Tukey test (p ≤ 0.05). The flow value of Apexit Plus was greater than Sealapex, whereas the radiopacity (3.44 mm Al) was lower than Sealapex (6.82 mm Al). Apexit Plus showed lower solubility and shorter initial and final setting (p < 0.0001), whereas the antimicrobial activity was significantly greater than Sealapex. Although the number of ICs was higher in Apexit Plus (p = 0.0009) at 7 days, no significant difference was detected between Apexit Plus and Sealapex at 15, 30, and 60 days. All groups showed higher values for BC in the capsules over time. ALP-immunolabelled cells were observed, mainly around von Kossa-positive structures, either in the capsules of Apexit Plus or Sealapex. Therefore, our results revealed that Apexit Plus exhibited a greater effectiveness against Enterococcus faecalis and better physical properties than Sealapex, except for the radiopacity. In vivo findings indicate that Apexit Plus is biocompatible and presents potential bioactivity in the subcutaneous tissue.

scholarly journals In vivo investigation of the tissue response to commercial Teflon insulin infusion sets in large swine for 14 days: the effect of angle of insertion on tissue histology and insulin spread within the subcutaneous tissue

2019 ◽  
Vol 7 (1) ◽  
pp. e000881 ◽  
Author(s):  
Gabriella Eisler ◽  
Jasmin R Kastner ◽  
Marc C Torjman ◽  
Abdurizzagh Khalf ◽  
David Diaz ◽  
...  
Keyword(s):  
Insulin Infusion ◽  
Subcutaneous Tissue ◽  
Pressure Profile ◽  
Tissue Response ◽  
Pressure Curve ◽  
Wear Time ◽  
Insertion Angle ◽  
Significant Difference ◽  
Design And Methods

ObjectiveThis study investigated the effects of the inflammatory tissue response (ITR) to an insulin infusion set (IIS) on insulin bolus spread over wear time, as well as the effect of cannula insertion angle on the ITR, bolus shape, and pump tubing pressure.Research design and methodsAngled or straight IISs were inserted every other day for 14 days into the subcutaneous tissue of 11 swine and insulin was delivered continuously. Prior to euthanasia, a 70 µL bolus of insulin/X-ray contrast agent was infused while recording a pressure profile (peak tubing pressure, pmax; area under the pressure curve, AUC), followed by the excision of the tissue-catheter specimen. Bolus surface area (SA) and volume (V) were assessed via micro-CT. Tissue was stained to analyze total area of inflammation (TAI) and inflammatory layer thickness (ILT) surrounding the cannula.ResultsA bolus delivered through an angled IIS had a larger mean SA than a bolus delivered through a straight cannula (314.0±84.2 mm2 vs 229.0±99.7 mm2, p<0.001) and a larger volume (198.7±66.9 mm3 vs 145.0±65.9 mm3, p=0.001). Both decreased significantly over wear time, independent of angle. There was a significant difference in TAI (angled, 9.1±4.0 mm2 vs straight, 14.3±8.6 mm2, p<0.001) and ILT (angled, 0.7±0.4 vs straight, 1.2±0.7 mm, p<0.001). pmax (p=0.005) and AUC (p=0.014) were lower using angled IIS. As ILT increased, pmax increased, while SA and V decreased.ConclusionsThe progression of the ITR directly affected bolus shape and tubing pressure. Although straight insertion is clinically preferred, our data suggest that an angled IIS elicits lower grades of ITR and delivers a bolus with lower tubing pressure and greater SA and V. The subcutaneous environment plays a crucial role in IIS longevity, and the insertion angle needs to be considered in future IIS designs and clinical trials.

Relationship between higher rates of adverse events in deep brain stimulation using standardized prospective recording and patient outcomes

2010 ◽  
Vol 29 (2) ◽  
pp. E4 ◽  
Author(s):  
Adam P. Burdick ◽  
Hubert H. Fernandez ◽  
Michael S. Okun ◽  
Yueh-Yun Chi ◽  
Charles Jacobson ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Adverse Events ◽  
Motor Function ◽  
Brain Stimulation ◽  
Rating Scale ◽  
Short Form ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Significant Difference ◽  
Deep Brain

Object Adverse event (AE) rates for deep brain stimulation (DBS) are variable, due to various methodologies used for identifying, collecting, and reporting AEs. This lack of a prospective, standardized AE collection method is a shortcoming in the advancement of DBS. In this paper the authors disclose the standardized and prospectively recorded AE data from their institution, correlated with clinical outcome and quality of life (QOL) measures. Methods All patients who underwent operations at the authors' institution for Parkinson disease (PD), essential tremor, dystonia, other tremor, and obsessive-compulsive disorder were included. Complications occurring intraoperatively or within the first 180 days following surgery were recorded, analyzed, and classified as mild, moderate, or severe, regardless of their perceived relationship to the procedure. The presence, frequency, and severity of AEs were compared with the following outcome measurements: postoperative change in the QOL scales (Medical Outcomes Study 36-Item Short-Form Survey, 39-Item PD Questionnaire); motor scales (Tremor Rating Scale, Unified Dystonia Rating Scale, Unified PD Rating Scale); and Patient Global Impression Scale (PGIS). Results Two hundred seventy DBS procedures were performed in 198 patients. Three hundred AEs were recorded in 146 (54.1%) of the 270 procedures, and the AEs were recorded in 119 (60.1%) of 198 patients. Of the 198 patients, the maximum severity of AEs was mild in 28 (14.1%), moderate in 35 (17.7%), and severe in 56 (28.3%). Of the 300 AEs, 102 (34.1%) of 299 were mild, 106 (35.5%) were moderate, and 91 (30.4%) were severe. The AEs were classified as probably not stimulation induced in 10 (3.4%) of 297, probably in 44 (14.9%), unclear for 89 (30%), and not applicable to stimulation in 154 (51.9%). Adverse events were also classified as probably related to surgery in 111 (37.2%) of 298, possibly related in 96 (32.2%), and probably not related to surgery in 91 (30.5%). There was no significant difference (p = 0.22) in QOL outcomes among patients who had no AEs compared with those who experienced mild, moderate, or severe AEs. There was no significant difference in QOL outcomes between patients who did not experience an AE compared with those who experienced any AE. There was no significant difference in the mean General PGIS score between patients without an AE versus those with any AE, as well as on the Symptom-Specific PGIS. Motor function outcomes did not vary between patients with or without AEs. For patients with PD with or without AEs, there was no significant difference in preoperative off-medicine Unified PD Rating Scale score and postoperative 6-month on-medication/on-stimulation change scores (p = 0.59). For patients with tremor there were no differences between those with or without AEs on the Tremor Rating Scale for motor function or activities of daily living. Patients with dystonia with and without AEs showed no differences in the Unified Dystonia Rating Scale. Conclusions Prospectively and systematically recording AEs may result in higher AE rates, but this does not correlate with poorer QOL, motor function, or patient-oriented outcome scores.

scholarly journals Disability and functional outcomes following STN, VC/VS, and combined deep brain stimulation in obsessive compulsive disorder

BJPsych Open ◽  
2021 ◽  
Vol 7 (S1) ◽  
pp. S298-S299
Author(s):  
Himanshu Tyagi
Keyword(s):  
Deep Brain Stimulation ◽  
Obsessive Compulsive Disorder ◽  
Brain Stimulation ◽  
Obsessive Compulsive ◽  
Specialist Service ◽  
Double Blind ◽  
Compulsive Disorder ◽  
Severity Scores ◽  
Significant Difference ◽  
Deep Brain

BackgroundOCD severity scores mostly convey information within the domain of clinical conceptualisations. To capture the full impact of any new intervention it is crucial to measure its impact on disability. For this purpose we captured prospective data on changes in disability, function and impairments with multiple tools throughout the UCL-MRC trial of Deep brain stimulation (DBS) for Obsessive Compulsive Disorder (OCD) between 2013-2017. The clinical and cognitive outcomes from the trial have already been reported in 2019. We hypothesized a concomitant improvement in perceived and observed indicators of disability with clinical improvement in OCD symptoms. This is a preliminary report of the disability outcome data from the trial.MethodSix patients with severe treatment resistant OCD were recruited for this study from the NHS England OCD Specialist Service. Eligible participants were offered lesion surgery (anterior cingulotomy) or entry to the DBS trial. OCD medication was kept constant throughout the trial. We tested the effects of DBS by comparing baseline, VC/VS, STN, both sites and CBT stages of trial on the following three assessments of function: GAF, SDS and CAOIC. An impairment focussed interview was done to quantify changes in function specific to OCD. Friedman's test was used to test for DBS effects during the double-blind crossover phases comparing baseline, amSTN and VC/VS. Post-hoc pair-wise Conover tests for significant effects were used with FDR corrections. All significant results are reported at P < 0.05.ResultDBS had a significant effect across all phases for all above mentioned clinical measures. For all three measures of disability, there were significant improvements after both amSTN and VC/VS DBS. For all three measures of disability the effect of VC/VS DBS was significantly better that amSTN DBS. For all three measures of disability there was a non-significant trend (p = 0.058) for stimulation at both sites to have a better effect than stimulation of one site alone. For all three measures of disability, there were no significant difference between DBS alone and DBS and CBT.ConclusionThis study is the first to have directly compared differential effects of STN versus VC/VS DBS stimulation in OCD patients whilst testing clinical, cognitive and disability outcomes. The results of this study indicate that although both sites are equally effective in reducing OCD, stimulating VC/VS leads to a significantly greater improvement on disability scores in severe OCD.

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.

In-vivo evaluation of the effect of cyanoacrylate on prosthetic vascular graft infection – does cyanoacrylate increase the severity of infection?

VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 281-284
Author(s):  
Atıf Yolgosteren ◽  
Gencehan Kumtepe ◽  
Melda Payaslioglu ◽  
Cuneyt Ozakin
Keyword(s):  
Vascular Graft ◽  
Graft Infection ◽  
Vascular Graft Infection ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Prosthetic Vascular Graft Infection ◽  
Group 1

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.

Reducing the Social Stigma Associated with Obsessive Compulsive Disorder: A Controlled Trial of an Intervention Program in a Turkish Community Sample

2020 ◽  
Vol 20 (2) ◽  
pp. 101-120
Author(s):  
Ayça Aktaç Gürbüz ◽  
Orçun YORULMAZ ◽  
Gülşah DURNA
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Intervention Program ◽  
Controlled Trial ◽  
Community Sample ◽  
Case Vignette ◽  
Control Group ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Significant Difference ◽  
The Impact

Scientific research into the reduction of stigmatization, particularly related to specific problems such as Obsessive-Compulsive Disorder (OCD), is scarce. In the present study, we examine the impact of a video-based antistigma intervention program for OCD in a pretest-posttest control group research. After being randomly assigned to either an intervention (n= 101) or control group (n= 96), the participants reported their attitudes on a hypothetical case vignette before and after OCD vs. Multiple Sclerosis (MS) videos, and again six months later as a follow up assessment. The mixed design analyses for the group comparisons indicated that although there was no significant difference in the measures of the control group, the participants watching the anti-stigma OCD video, in which the focus was psychoeducation and interaction strategies, reported significantly lower scores on social distances and negative beliefs for the case vignettes they read, and this difference was maintained six months later. Then, the present results indicate the effectiveness of our anti-stigma intervention program for OCD. Interventions to reduce stigmatization can also be viewed as effective tools for changing the attitudes of people toward OCD, although further research and applications are needed related to specific disorders if a longlasting impact is to be achieved.

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