Oxygen intake, ventilation and heart rate were measured in six subjects performing ergometer exercise at various altitudes from sea level to 7,440 m (24,400 ft) (Bar. 300 mm Hg) during a Himalayan expedition lasting 8 months. intake for given work was constant independent of altitude, up the maximum that could be maintained 5 min. Maximum oxygen declined with increase reaching 1.46 liters/min best subject. Ventilation (STPD) altitude light moderate but increased each as approached. values...

Arterial oxygen saturations were measured on six members of the Himalayan Scientific and Mountaineering Expedition, 1960–61, during a wintering period at 19,000 ft (5,800 m; Pb 380 mm Hg). The determinations made by ear oximetry analysis venous blood from heated hand rest exercise work levels up to 1,200 kg-m/min. Expired gas volumes concentrations also measured. average arterial saturation was 67%, 300 900 kg-m/min it 63 56%, respectively. Several readings less than 50% recorded severe...

Abstract Vagus nerve stimulation (VNS) is thought to affect neural activity by recruiting brain-wide release of neuromodulators. VNS used in treatment-resistant epilepsy, and increasingly being explored for other disorders, such as depression, a cognitive enhancer. However, the promise only partially fulfilled due lack mechanistic understanding transfer function between parameters neuromodulatory response, together with biosensors assaying efficacy real time. We here develop an approach...

ABSTRACT The use of focused ultrasonic waves to modulate neural structures has gained recent interest due its potential in treating neurological disorders noninvasively. While several articles have on the ultrasound neuromodulation peripheral nerves, none these studies been performed vagus nerve. We present preliminary observations effects pulsed (FPUS) conduction left cervical nerve a Long Evans rat. Ultrasound energy was applied at frequency 1.1 MHz, and spatial‐peak, temporal average...

Vagus nerve stimulation (VNS) is an emerging electroceutical therapy for remedying gastric disorders that are poorly managed by pharmacological treatments and/or dietary changes. Such seems promising as the vagovagal neurocircuitry modulates enteric nervous system to influence functions.Here, modulatory effects of left cervical VNS on emptying in rats were quantified using a (i) feeding protocol which animal voluntarily consumed postfast, gadolinium-labeled meal and (ii) non-invasive imaging...

Vagus nerve stimulation (VNS) is a promising therapy for many neurologic and psychiatric conditions. However, determining stimulus parameters individual patients major challenge. The traditional method of titrating intensity based on patient perception produces highly variable responses. This study explores using the vagal response to measure dose predict physiological effect. Clinicians are investigating use VNS heart failure management, this work aims correlate cardiac measures with fiber...

Abstract The vagus nerve (VN) plays an important role in regulating physiological conditions the gastrointestinal (GI) tract by communicating via parasympathetic pathway to enteric nervous system (ENS). However, lack of knowledge neurophysiology VN and GI limits development advanced treatments for autonomic dysfunctions related VN. To better understand complicated underlying mechanisms VN-GI neurophysiology, it is necessary use device enabled microfabrication technologies. Among several...

Inflammatory Airway Disease (IAD), exercise-induced pulmonary hemorrhage (EIPH), and upper airway obstruction (UAO) are common respiratory tract diseases that can decrease performance. The purpose of this retrospective study was to compare bronchoalveolar lavage fluid cytology arterial blood gas analysis during a treadmill test by poorly performing racehorses presented Purdue University. One hundred thirty-two horses with history poor performance were included in study. Ten no or diagnosis...

Epilepsy affects more than 1% of the world's population. Responsive neurostimulation is emerging as an alternative therapy for 30% epileptic patient population that does not benefit from pharmacological treatment. Efficient seizure detection algorithms will enable closed-loop epilepsy prostheses by stimulating epileptogenic focus within early onset window. Critically, this expected to reduce neuronal desensitization over time and lead longer-term device efficacy. This work presents a novel...

Inflammatory Airway Disease (IAD), exercise‐induced pulmonary hemorrhage (EIPH), and upper airway obstruction (UAO) are common respiratory tract diseases that can decrease performance. The purpose of this retrospective study was to compare bronchoalveolar lavage fluid cytology arterial blood gas analysis during a treadmill test by poorly performing racehorses presented Purdue University. One hundred thirty‐two horses with history poor performance were included in study. Ten no or diagnosis...

Preliminary results from animal and clinical studies demonstrate that electrical stimulation of brain structures can reduce seizure frequency in patients with refractory epilepsy. Since most researchers derive parameters by trial error, it is unclear what frequency, amplitude duration constitutes a set optimal for aborting activity given patient. In this investigation, we begin to quantify the independent effects on electrographic seizures, such they could be used develop an efficient...

Electrical vagus nerve stimulation is a treatment alternative for many epileptic and depressed patients whose symptoms are not well managed with pharmaceutical therapy. However, the fixed stimulus, open loop dosing mechanism limits its efficacy precludes major advances in quality of A real-time, responsive form needed to control activation according therapeutic need. This personalized approach therapy will improve reduce number severity side effects. We present autonomous neural control,...

Vagus nerve stimulation (VNS) is a recognized treatment for neurological disorders, yet the surgical procedure carries significant risks. During process of isolating or cuffing vagus nerve, there danger damaging itself adjacent carotid artery jugular vein. To minimize this risk, here we introduce novel hydrogel adhesive-integrated and stretchable microdevice that provides less invasive, cuff-free option interfacing with nerve. The device features adhesive formulation enables crosslinking on...

Effective response to vaccination requires activation of the innate immune system, triggering synthesis inflammatory cytokines. The degree subjective symptoms related this, referred as reactogenicity, may predict their eventual response. However, nature these is influenced by nocebo effect, making it difficult accurately quantify a person's physiologic use wearable sensors allows for identification objective evidence changes person experiences following vaccination, but are subtle, they can...

In this paper, we present a noise, power, and area efficient biosensing front-end application specified integrated circuit (ASIC) for the next-generation wireless body sensor nodes implantable devices. We identify key design parameter tradeoffs in biomedical recording systems carry out thorough analysis optimization to maximize them. Based on our of front end, propose methodology channel that is applicable various applications. The ASIC implemented 0.18-μm CMOS process validate methodology....

We demonstrate an alternative method of designing electrical stimuli-termed burst modulation--for producing different patterns nerve fiber recruitment. By delivering charge in bursts "pulsons"--miniature pulses-instead as long continuous pulses, our can optimize the waveform for stimulation efficiency and selectivity. In vivo validation experiments, while maintaining C fibers rat vagus at ∼ 50% activation with waveforms, burst-modulated produced 11% less A than standard rectangular pulse...

Numerous studies of vagal nerve stimulation (VNS) have been published showing it to be a potential treatment for chronic inflammation and other related diseases disorders. Studies in recent years shown that electrical the efferent fibers can artificially modulate cytokine levels reduce systematic inflammation. Most VNS research acute on rodent subjects. Our study tested freely moving animals by stimulating recording from cervical vagus with cuff electrodes over an extended period time.We...

The vagus nerve provides motor, sensory, and autonomic innervation of multiple organs, electrical stimulation (VNS) an adjunctive treatment option for e.g. medication-refractory epilepsy treatment-resistant depression. mechanisms action VNS are not known, high-resolution anatomical mapping the human is needed to better understand its functional organization. Electron microscopy (EM) required detection both myelinated unmyelinated axons, but access well-preserved nerves ultrastructural...

REVIEW article Front. Neuroeng., 31 May 2010 | https://doi.org/10.3389/fneng.2010.00007

Neural recording and stimulation have great clinical potential. Long-term neural remains a challenge, however, as implantable electrodes eventually fail due to the adverse effects of host tissue response indwelling implant. Astrocytes microglia attempt engulf electrode, increasing electrical impedance between electrode neurons, possibly pushing neurons away from site. Faster insertion speed, finer tip geometry, smaller size, lower material stiffness all seem decrease damage caused by reduce...

Serum immunoglobulin levels were determined in 25 patients with frozen shoulder and age- sex-matched controls. IgA significantly reduced (P less than 0.001) the remained so after clinical recovery. Lymphocyte transformation to phytohaemagglutinin 21 also showed significant depression 0.01). These results support suggested immunological pathogenesis of this condition.