Preface.

Following four papers were authored by the graduating class at McMaster University, Hamilton, Ontario, Canada, in 2021 and 2022 and are a part of this issue. They examine a variety of paradigms wherein long term implants are either evaluated for their efficacy or how health related quality of life (HRQoL) is affected by an implant.

Electrostimulation for Refractory Epilepsy: A Review.

Epilepsy is a neurological disorder that has been diagnosed in approximately 1% of the world's population. In North America alone, more than 3 million individuals suffer from epilepsy. Antiepileptic drugs are not fully effective in some patients, and most drugs have adverse side effects.

Deep Brain Stimulation as a Treatment for Refractory Epilepsy: Review of the Current State-of-the-Art.

Epilepsy affects ∼ 1% of the global population, and 33% of patients are nonresponsive to medication and must seek alternative treatment options. Alternative options such as surgery and ablation exist but are not appropriate treatment plans for some patients. Neurostimulation methods such as vagal nerve stimulation, responsive neural stimulation, and deep brain stimulation (DBS) are viable alternatives for medically refractory patients.

Deep Learning in Gastrointestinal Endoscopy.

Gastrointestinal (GI) endoscopy is used to inspect the lumen or interior of the GI tract for several purposes, including, (1) making a clinical diagnosis, in real time, based on the visual appearances; (2) taking targeted tissue samples for subsequent histopathological examination; and (3) in some cases, performing therapeutic interventions targeted at specific lesions. GI endoscopy is therefore predicated on the assumption that the operator-the endoscopist-is able to identify and characterize abnormalities or lesions accurately and reproducibly. However, as in other areas of clinical medicine, such as histopathology and radiology, many studies have documented marked interobserver and intraobserver variability in lesion recognition.

Air Pollution's Effects on the Human Respiratory System.

The World Health Organization defines air pollution as "any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere." The most common pollutants include particulate matter, carbon monoxide, ozone, nitrogen oxide, and sulfur dioxide. The two types of air pollution, indoor and ambient, both contribute to a host of cardiac and respiratory illnesses.

Air Pollution and Cardiovascular Disease: A Review.

Air pollution is comprised of different compounds and particulate matter (PM) of sizes 2.5 and 10 μm, with the former size posing the greatest danger to humans. Evidence suggests that the global rise in air pollution levels during the past century is correlated with the increased incidence of diseases of the cardiovascular system.

Review of Texture Quantification of CT Images for Classification of Lung Diseases.

Computer-based identification of abnormal regions and classification of diseases using CT images of the lung has been a goal of many investigators. In this paper, we review research that has used texture analysis along with segmentation and fractal analysis. First, a review of texture methods is performed.

Modeling the weaning of intensive care unit patients from mechanical ventilation: a review.

In the intensive care unit, mechanical ventilation is a life-saving procedure, and as many as 90% of patients require the intervention. For a mechanically ventilated patient, the principal goal of a health care team is to free the patient from mechanical ventilation through weaning as soon as possible. Weaning, however, still is mostly a manual process.

GERD and obesity: is the autonomic nervous system the missing link?

Gastroesophageal reflux disease (GERD) is a common chronic condition that not only impairs the quality of life of those who are affected by it but also poses a significant economic burden. It encompasses a wide spectrum of symptoms as a result of gastric content moving into the esophagus. The most common cause of GERD, other than a hiatus hernia, is considered to be transient lower esophageal sphincter relaxation.

A morphological algorithm for measuring angle of airway branches in lung CT images.

Accurate measurement of human airway lumen bifurcation angle in the bronchial tree may be an important parameter for evidence of pulmonary diseases. Here, we describe a new method for recognizing and following airway bifurcation over numerous contiguous CT images. Based on morphological properties of airways and specific changes to airway properties while digitally navigating through the bifurcation, our method is able to track airways through several levels of bifurcation.

A Multi-Step Algorithm for Measuring Airway Luminal Diameter and Wall Thickness in Lung CT Images.

Accurate measurements of airway diameter and wall thickness are important parameters in understanding numerous pulmonary diseases. Here, we describe an automated method of measuring small airway luminal diameter and wall thickness over numerous contiguous computed tomography (CT) images. Using CT lung images from 22 patients and an airway phantom, a seeded region-growing algorithm was first applied to identify the lumen of the airway.

Behavioral neurocardiac training in hypertension: a randomized, controlled trial.

It is not established whether behavioral interventions add benefit to pharmacological therapy for hypertension. We hypothesized that behavioral neurocardiac training (BNT) with heart rate variability biofeedback would reduce blood pressure further by modifying vagal heart rate modulation during reactivity and recovery from standardized cognitive tasks ("mental stress"). This randomized, controlled trial enrolled 65 patients with uncomplicated hypertension to BNT or active control (autogenic relaxation), with six 1-hour sessions over 2 months with home practice.

Longer-term effects of implanted vagal nerve stimulation.

Vagal nerve stimulation (VNS) is a non-pharmacologic therapeutic intervention approved in adults and children with neuropsychiatric disorders. Studies conducted over the past 20 years have demonstrated that VNS results in immediate and longer-term changes in brain regions implicated in neuropsychiatric disorders, such as the thalamus, cerebellum, orbitofrontal cortex, limbic system, hypothalamus, and medulla with vagus innervations. This review summarizes the effects of longer-term implanted VNS and how the incorporation of this non-pharmacologic therapeutic management in the treatment regime can be beneficial to address the needs of patients who are unable to tolerate medications and/or undergo surgery and do not respond to pharmacologic therapies.

Evaluation of the efficacy and performance of medical implants: a review.

An implant can be defined, in a medical context, as biological or artificial materials inserted or grafted into the body. Implants may be sensory devices (cochlear, ocular), mechanical devices that are 'passive' (orthopedic joint replacements and fixation plates, dental implants, coronary artery stents and vascular grafts) or 'active' (left ventricular assist devices, heart valves) electrophysiological stimulation devices (cardiac or gastric pacemakers, implantable cardiac defibrillators, functional electrical stimulators for epilepsy or Parkinson's disease) or medication administration devices (insulin or analgesic delivery pumps) or intra-ocular sustained drug release implants. Implantation has had a long history in several subspecialties of medicine.

Advances in multimodality imaging through a hybrid PET/MRI system.

The development of integrated imaging systems for magnetic resonance imaging (MRI) and positron emission tomography (PET) is currently being explored in a number of laboratories and industrial settings. PET/MRI scanners for both preclinical and human research applications are being developed. PET/MRI overcomes many limitations of PET/computed tomography (CT), such as limited tissue contrast and high radiation doses delivered to the patient or the animal being studied.

The effect of depression on heart rate variability during pregnancy. A naturalistic study.

Depression during pregnancy has been associated with a number of adverse outcomes, but the underlying physiological mechanisms involved remain unclear. The purpose of this study was to examine the effects of maternal depression during pregnancy on the autonomic modulation of heart rate, in a naturalistic setting. Eighty-one pregnant women were studied between 25 and 31 weeks of gestation and were identified as either Depressed (n = 46), or healthy, Control (n = 35), based on depression scores and lifetime psychiatric history.

Segmentation of images of abdominal organs.

Abdominal organ segmentation, which is, the delineation of organ areas in the abdomen, plays an important role in the process of radiological evaluation. Attempts to automate segmentation of abdominal organs will aid radiologists who are required to view thousands of images daily. This review outlines the current state-of-the-art semi-automated and automated methods used to segment abdominal organ regions from computed tomography (CT), magnetic resonance imaging (MEI), and ultrasound images.

The effect of depression, anxiety and early life trauma on the cortisol awakening response during pregnancy: preliminary results.

The purpose of this study was to examine the effects of maternal depression and anxiety on the cortisol awakening response (CAR), a marker of the hypothalamic-pituitary-adrenal (HPA) axis function, during pregnancy. Sixty-six pregnant women were studied between 25 and 33 weeks of gestation and were identified as either Depressed (n=33) or healthy, Control (n=33), based on depression scores and lifetime psychiatric history. Saliva samples were collected (passive drool) upon awakening and at +30 and +60 min thereafter.

13C urea breath test for (Helicobacter pylori): evaluation of 10-minute breath collection.

Aim: To determine whether a shortened (13)C urea breath test ((13)C UBT) (breath collection time of 10 min) is as reliable as the standard assay (30 min).

Methods: Two hundred ninety-seven patients (mean +/- SD: 53+/-16 years, 57% female) completed a (13)C UBT. Breath samples were obtained at baseline and at 5 min intervals up to 30 min.

13C urea breath test for (Helicobacter pylori): determination of the optimal cut-off point in a Canadian community population.

Aim: To determine the test characteristics and the optimal cut-off point for the (13)C urea breath test ((13)C UBT) in a Canadian community laboratory setting.

Methods: Of 2232 patients (mean age +/- SD: 51+/-21 years, 56% female) who completed a (13)C UBT, 1209 were tested to evaluate the primary diagnosis of (Helicobacter pylori) infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the (13)C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results.

Noradrenergic and cholinergic neural pathways mediate stress-induced reactivation of colitis in the rat.

Evidence to date suggests that stress-induced exacerbation or relapse of intestinal inflammation in inflammatory bowel disease requires both activation of the autonomic nervous system and the activation of the immune system by the presence of previously encountered luminal antigens. The aim of the present study was to further explore these associations and to determine the role of the autonomic nervous in modulating the intestinal inflammatory response to stress. Rats healed from an initial dinitrobenzene sulfonic acid-induced colitis were given a non-colitic dose of dinitrobenzene sulfonic acid (dissolved in saline) or 0.

Induction of compulsive-like washing by blocking the feeling of knowing: an experimental test of the security-motivation hypothesis of obsessive-compulsive disorder.

Background: H. Szechtman and E. Woody (2004) hypothesized that obsessive-compulsive disorder results from a deficit in the feeling of knowing that normally terminates thoughts or actions elicited by security motivation.