Inline flow sensor for ventriculoperitoneal shunts: Experimental evaluation in swine.

Shunts are commonly employed to treat hydrocephalus, a severe central nervous disease caused by the buildup of cerebrospinal fluid in the brain. These shunts divert excessive cerebrospinal fluid from brain ventricles to other body cavities, thereby relieving the symptoms. However, these shunts are highly prone to failure due to obstruction from cellular debris, leading to cerebrospinal fluid accumulation in the brain and exacerbation of neurological symptoms.

Homer binds to Orai1 and TRPC channels in the neointima and regulates vascular smooth muscle cell migration and proliferation.

The molecular components of store-operated Ca influx channels (SOCs) in proliferative and migratory vascular smooth muscle cells (VSMCs) are quite intricate with many channels contributing to SOCs. They include the Ca-selective Orai1 and members of the transient receptor potential canonical (TRPC) channels, which are activated by the endoplasmic reticulum Ca sensor STIM1. The scaffolding protein Homer assembles SOC complexes, but its role in VSMCs is not well understood.

Featured Article: Pyruvate preserves antiglycation defenses in porcine brain after cardiac arrest.

Cardiac arrest (CA) and cardiocerebral resuscitation (CCR)-induced ischemia-reperfusion imposes oxidative and carbonyl stress that injures the brain. The ischemic shift to anaerobic glycolysis, combined with oxyradical inactivation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), provokes excessive formation of the powerful glycating agent, methylglyoxal. The glyoxalase (GLO) system, comprising the enzymes glyoxalase 1 (GLO1) and GLO2, utilizes reduced glutathione (GSH) supplied by glutathione reductase (GR) to detoxify methylglyoxal resulting in reduced protein glycation.

δ-Opioid receptors: Pivotal role in intermittent hypoxia-augmentation of cardiac parasympathetic control and plasticity.

Background: Intermittent hypoxia training (IHT) produces robust myocardial protection against ischemia-reperfusion induced infarction and arrhythmias. Blockade of this cardioprotection by antagonism of either β1-adrenergic or δ-opioid receptors (δ-OR) suggests autonomic and/or opioidergic adaptations.

Purpose: To test the hypothesis that IHT shifts cardiac autonomic balance toward greater cholinergic and opioidergic influence.

δ-Opioid receptor (DOR) signaling and reactive oxygen species (ROS) mediate intermittent hypoxia induced protection of canine myocardium.

Intermittent, normobaric hypoxia confers robust cardioprotection against ischemia-induced myocardial infarction and lethal ventricular arrhythmias. δ-Opioid receptor (DOR) signaling and reactive oxygen species (ROS) have been implicated in cardioprotective phenomena, but their roles in intermittent hypoxia are unknown. This study examined the contributions of DOR and ROS in mediating intermittent hypoxia-induced cardioprotection.

Pyruvate stabilizes electrocardiographic and hemodynamic function in pigs recovering from cardiac arrest.

Cardiac electromechanical dysfunction may compromise recovery of patients who are initially resuscitated from cardiac arrest, and effective treatments remain elusive. Pyruvate, a natural intermediary metabolite, energy substrate, and antioxidant, has been found to protect the heart from ischemia-reperfusion injury. This study tested the hypothesis that pyruvate-enriched resuscitation restores hemodynamic, metabolic, and electrolyte homeostasis following cardiac arrest.

Pyruvate-enriched resuscitation: metabolic support of post-ischemic hindlimb muscle in hypovolemic goats.

Tourniquet-imposed ischemia-reperfusion of extremities generates reactive oxygen and nitrogen species (RONS), which can disrupt intermediary metabolism and ATP production. This study tested the hypothesis that fluid resuscitation with pyruvate, a natural antioxidant and metabolic fuel, ameliorates the deleterious effects of ischemia-reperfusion on intermediary metabolism in skeletal muscle. Anesthetized male goats (∼25 kg) were bled to a mean arterial pressure of 48 ± 1 mmHg and then subjected to 90 min hindlimb ischemia with a tourniquet and femoral crossclamp, followed by 4-h reperfusion.

Lymphatic pump treatment increases thoracic duct lymph flow in conscious dogs with edema due to constriction of the inferior vena cava.

Background: Osteopathic lymphatic pump treatments (LPT) are used to treat edema, but their direct effects on lymph flow have not been studied. In the current study, we examined the effects of LPT on lymph flow in the thoracic duct of instrumented conscious dogs in the presence of edema produced by constriction of the inferior vena cava (IVC).

Methods And Results: Six dogs were surgically instrumented with an ultrasonic flow transducer on the thoracic lymph duct and catheters in the descending thoracic aorta and in IVC.

Lymph flow in instrumented dogs varies with exercise intensity.

Background: Although it is generally accepted that exercise accelerates lymph flow, no study has directly measured lymph flow as a function of exercise intensity. In this study, we have measured flow in the thoracic lymph duct of five instrumented dogs while they ran on a treadmill.

Methods And Results: Dogs were surgically instrumented with an ultrasonic flow transducer on the thoracic lymph duct and a catheter in the descending thoracic aorta.

Vagal modulation of heart rate variability during atrial fibrillation in pigs.

Atrial fibrillation (AF) is the most common sustained cardiac dysrhythmia and is associated with an increased risk for sudden cardiac death. The ventricular rhythm is irregular and displays both non-linear and linear patterns; however, it has not been determined whether vagally derived patterns are manifest within the irregular rhythm. Moreover, indices of increased vagal control are associated with reduced risk of sudden cardiac death.

Lymph flow in the thoracic duct of conscious dogs during lymphatic pump treatment, exercise, and expansion of extracellular fluid volume.

Background: This investigation examined interactions between expansion of the extracellular fluid volume (ECE), osteopathic lymphatic pump treatment (LPT), and exercise on lymph flow in the thoracic duct of eight instrumented, conscious dogs.

Methods And Results: After recovery from surgery, LPT was performed for 8 min before and after ECE with normal saline, i.v.

Abdominal lymphatic pump treatment increases leukocyte count and flux in thoracic duct lymph.

Background: Previous studies suggest that rhythmic compression of the abdomen (abdominal lymphatic pump techniques, LPT) enhances immunity and resistance to infectious disease, but direct evidence of this has not been documented. In this study, the thoracic duct of eight anesthetized mongrel dogs was catheterized, so the immediate effects of LPT on lymph flow and leukocyte output could be measured.

Methods And Results: Lymph flow was measured by timed collection or ultrasonic flowmeter, and lymph was collected over ice under 1) resting (baseline) conditions, and 2) during application of LPT.

Oxidative stress reversibly inactivates myocardial enzymes during cardiac arrest.

Oxidative stress during cardiac arrest may inactivate myocardial enzymes and thereby exacerbate ischemic derangements of myocardial metabolism. This study examined the impact of cardiac arrest on left ventricular enzymes. Beagles were subjected to 5 min of cardiac arrest and 5 min of open-chest cardiac compressions (OCCC) before epicardial direct current countershocks were applied to restore sinus rhythm.

Beta1-Adrenergic receptor antagonism abrogates cardioprotective effects of intermittent hypoxia.

Adaptation to hypoxia lessens myocardial ischemic injury. This study tested whether hypoxia-induced beta-adrenergic activity mobilizes mechanisms that protect myocardium during subsequent ischemia and reperfusion. Dogs were intermittent hypoxia conditioned (IHC) by a 20 days program of 5-8 daily, 5-10 min cycles of normobaric hypoxia (FIO2 = 9.