Neuromodulation using ultra low frequency current waveform reversibly blocks axonal conduction and chronic pain.

Chronic pain remains a leading cause of disability worldwide, and there is still a clinical reliance on opioids despite the medical side effects associated with their use and societal impacts associated with their abuse. An alternative approach is the use of electrical neuromodulation to produce analgesia. Direct current can block action potential propagation but leads to tissue damage if maintained.

Cancer-Selective Treatment of Cancerous and Non-Cancerous Human Cervical Cell Models by a Non-Thermally Operated Electrosurgical Argon Plasma Device.

Cold atmospheric plasma (CAP) treatment is developing as a promising option for local anti-neoplastic treatment of dysplastic lesions and early intraepithelial cancer. Currently, high-frequency electrosurgical argon plasma sources are available and well established for clinical use. In this study, we investigated the effects of treatment with a non-thermally operated electrosurgical argon plasma source, a Martin Argon Plasma Beamer System (MABS), on cell proliferation and metabolism of a tissue panel of human cervical cancer cell lines as well as on non-cancerous primary cells of the cervix uteri.

Recent Developments in Catheter-Based Cardiac Procedures.

New developments in transcatheter valve technologies including aortic valve replacement and mitral valve and tricuspid valve interventions are described. Recent studies evaluating the success rate, patient outcomes, and anesthesiologic management of the procedures are discussed.

Dose-Dependent Tissue-Level Characterization of a Medical Atmospheric Pressure Argon Plasma Jet.

Nonthermal treatment with cold atmospheric plasma (CAP) is a promising option for local treatment of chronic-inflammatory and precancerous lesions as well as various mucosal cancer diseases, besides its primary indication for wound healing and antiseptics. Atmospheric pressure plasma jets (APPJs) are versatile plasma sources, some of which are well-characterized and medically approved. The characterization of APPJs, however, is often based on the treatment of simple solutions or even studies on the plasma effluent itself.

Agreement of tricuspid annular systolic excursion measurement between transthoracic and transesophageal echocardiography in the perioperative setting.

Objective: The aim of our study was to evaluate the level of agreement between tricuspid annular plane systolic excursion (TAPSE) measured by transthoracic echocardiography (TTE) and TAPSE measured using transesophageal echocardiography (TEE) in anesthetized patients.

Materials And Methods: Thirty patients scheduled for elective cardiac surgery were prospectively studied. Shortly after induction of anesthesia before the operation, TAPSE was measured by TTE using M-mode in apical 4chamber view (4CH) and by TEE in six different views: using 2D echocardiography in midesophageal (ME) 4CH view, using M-mode in deep transgastric right ventricle (dTG RV) view at 0° and dTG RV longaxis view (LAX) as well as using anatomical M-mode (AM-mode) in ME 4CH, dTG RV at 0° and dTG RV LAX views.

Energy efficient neural stimulation: coupling circuit design and membrane biophysics.

The delivery of therapeutic levels of electrical current to neural tissue is a well-established treatment for numerous indications such as Parkinson's disease and chronic pain. While the neuromodulation medical device industry has experienced steady clinical growth over the last two decades, much of the core technology underlying implanted pulse generators remain unchanged. In this study we propose some new methods for achieving increased energy-efficiency during neural stimulation.

Dynamics and sensitivity analysis of high-frequency conduction block.

The local delivery of extracellular high-frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: (1) depolarizing currents promote conduction block via inactivation of sodium channels and (2) the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency.

Changes in plant species richness induce functional shifts in soil nematode communities in experimental grassland.

Background: Changes in plant diversity may induce distinct changes in soil food web structure and accompanying soil feedbacks to plants. However, knowledge of the long-term consequences of plant community simplification for soil animal food webs and functioning is scarce. Nematodes, the most abundant and diverse soil Metazoa, represent the complexity of soil food webs as they comprise all major trophic groups and allow calculation of a number of functional indices.

Electrical conduction block in large nerves: high-frequency current delivery in the nonhuman primate.

Recent studies have made significant progress toward the clinical implementation of high-frequency conduction block (HFB) of peripheral nerves. However, these studies were performed in small nerves, and questions remain regarding the nature of HFB in large-diameter nerves. This study in nonhuman primates shows reliable conduction block in large-diameter nerves (up to 4.

Separated interface nerve electrode prevents direct current induced nerve damage.

Direct current, DC, can be used to quickly and reversibly block activity in excitable tissue, or to quickly and reversibly increase or decrease the natural excitability of a neuronal population. However, the practical use of DC to control neuronal activity has been extremely limited due to the rapid tissue damage caused by its use. We show that a separated interface nerve electrode, SINE, is a much safer method to deliver DC to excitable tissue and may be valuable as a laboratory research tool or potentially for clinical treatment of disease.

Design, fabrication and evaluation of a conforming circumpolar peripheral nerve cuff electrode for acute experimental use.

Nerve cuff electrodes are a principle tool of basic and applied electro-neurophysiology studies and are championed for their ability to achieve good nerve recruitment with low thresholds. We describe the design and method of fabrication for a novel circumpolar peripheral nerve electrode for acute experimental use. This cylindrical cuff-style electrode provides approximately 270° of radial electrode contact with a nerve for each of an arbitrary number of contacts, has a profile that allows for simple placement and removal in an acute nerve preparation, and is designed for adjustment of the cylindrical diameter to ensure a close fit on the nerve.

Frequency- and amplitude-transitioned waveforms mitigate the onset response in high-frequency nerve block.

High-frequency alternating currents (HFAC) have proven to be a reversible and rapid method of blocking peripheral nerve conduction, holding promise for treatment of disorders associated with undesirable neuronal activity. The delivery of HFAC is characterized by a transient period of neural firing at its inception, termed the 'onset response'. The onset response is minimized for higher frequencies and higher amplitudes, but requires larger currents.

Conduction block of whole nerve without onset firing using combined high frequency and direct current.

This study investigates a novel technique for blocking a nerve using a combination of direct and high frequency alternating currents (HFAC). HFAC can produce a fast acting and reversible conduction block, but cause intense firing at the onset of current delivery. We hypothesized that a direct current (DC) block could be used for a very brief period in combination with HFAC to block the onset firing, and thus establish a nerve conduction block which does not transmit onset response firing to an end organ.

Effect of nerve cuff electrode geometry on onset response firing in high-frequency nerve conduction block.

The delivery of high-frequency alternating currents has been shown to produce a focal and reversible conduction block in whole nerve and is a potential therapeutic option for various diseases and disorders involving pathological or undesired neurological activity. However, delivery of high-frequency alternating current to a nerve produces a finite burst of neuronal firing, called the onset response, before the nerve is blocked. Reduction or elimination of the onset response is very important to moving this type of nerve block into clinical applications since the onset response is likely to result in undesired muscle contraction and pain.

Nerve conduction block using combined thermoelectric cooling and high frequency electrical stimulation.

Conduction block of peripheral nerves is an important technique for many basic and applied neurophysiology studies. To date, there has not been a technique which provides a quickly initiated and reversible "on-demand" conduction block which is both sustainable for long periods of time and does not generate activity in the nerve at the onset of the conduction block. In this study we evaluated the feasibility of a combined method of nerve block which utilizes two well established nerve blocking techniques in a rat and cat model: nerve cooling and electrical block using high frequency alternating currents (HFAC).

Combined direct current and high frequency nerve block for elimination of the onset response.

Nerve conduction in peripheral mammalian nerves can be blocked by high frequency alternating current (HFAC) waveforms. However, one of the disadvantages of HFAC block is that it produces an intense burst of firing in the nerve when the HFAC is first turned on. This is a significant obstacle to the clinical implementation of HFAC block.

Effect of bipolar cuff electrode design on block thresholds in high-frequency electrical neural conduction block.

Many medical conditions are characterized by undesired or pathological peripheral neurological activity. The local delivery of high-frequency alternating currents (HFAC) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and may provide a treatment alternative for eliminating pathological neural activity in these conditions. This work represents the first formal study of electrode design for high-frequency nerve block, and demonstrates that the interpolar separation distance for a bipolar electrode influences the current amplitudes required to achieve conduction block in both computer simulations and mammalian whole nerve experiments.

Conduction block of peripheral nerve using high-frequency alternating currents delivered through an intrafascicular electrode.

Many diseases are characterized by undesired or pathological neural activity. The local delivery of high-frequency currents has been shown to be an effective method for blocking neural conduction in peripheral nerves and may provide a therapy for these conditions. To date, all studies of high-frequency conduction block have utilized extraneural (cuff) electrodes to achieve conduction block.

Designing the optical interface of a transcutaneous optical telemetry link.

Optical telemetry has long been an option for transcutaneous data transfer and has been used in various types of implanted systems. This telemetry modality and the efficiency of these optical links are becoming ever more important as higher bandwidth sources such as cortical recording arrays are being implemented in implanted systems. The design of the transmitter-skin-receiver interface (the "optical interface") is paramount to the operation of a transcutaneous optical telemetry link.

Design of a high speed transcutaneous optical telemetry link.

In some neural prosthetic applications there is a need for high bandwidth communication between an implanted device and an external device. For example, transmitting 100 channels of neural waveform data for a cortical prosthetic control system may require up to 40 Mbps for a 100 channel array. Due to the high bandwidth required and its relative immunity from interference, optical telemetry is the most realistic method for achieving a clinically robust transcutaneous communication system capable of achieving these data rates.

The ponticulus posticus: implications for screw insertion into the first cervical lateral mass.

Background: The arcuate foramen is an important osseous anomaly of the first cervical vertebra (the atlas) that must be taken into consideration during placement of lateral mass screws into the atlas.

Methods: The prevalence of this anomaly in our patient population was determined through a retrospective review of 464 lateral radiographs of the neck. The anatomy of the arcuate foramen was identified in a study of cadavers.