John J Mulvihill

University of Limerick | UL · School of Engineering

Neurodegenerative diseases are a group of disorders characterised by progressive loss of brain function. The most common of these is Alzheimer’s disease, a form of dementia. Intake of macro- and micro-nutrients impacts brain function, including memory, learning, mood, and behaviour. Lipids, particularly phospholipids and sphingolipids, are crucial...

Mechanical changes to the microenvironment of the extracellular matrix (ECM) in tissue have been hypothesised to elicit a pathogenic response in the surrounding cells. Hence, 3D scaffolds are a popular method of studying cellular behaviour under conditions that mimic in vivo. To create a 3D biomimetic scaffold that captures the in vivo ECM microenv...

Objectives: To perform a multi-institutional investigation of incidence and outcomes of urethral trauma sustained during attempted catheterization. Patients & methods: A prospective, multi-center study was conducted over a designated 3-4 month period, incorporating seven academic hospitals across the UK and Ireland. Cases of urethral trauma aris...

Background Modelling of needle insertion in soft tissue has developed significant interest in recent years due to its application in robot-assisted minimally invasive surgeries such as biopsies and brachytherapy. However, this type of surgery requires real-time feedback and processing which complex computational models may not be able to provide....

Assessing the ability of pharmaceutics to cross biological barriers and reach the site-of-action requires faithful representation of these barriers in vitro. Difficulties have arisen in replicating in vivo resistance in vitro. This paper investigated serum starvation as a method to increase Caco-2 barrier stability and resistance. The effect of ser...

The cranial meninges have been shown to play a pivotal role in traumatic brain injury mechanopathology. However, while the mechanical response of the brain and its many subregions have been studied extensively, the meninges have conventionally been overlooked. This paper presents the first mechanical analysis of human dura mater, falx cerebri and s...

Cryopreservation is required to preserve the native properties of tissue for prolonged periods of time. In this study, we evaluate the impact that 4 different cryopreservation protocols have on porcine urethral tissue, to identify the method that best preserves the native properties of the tissue. The cryopreservation protocols include storage in c...

Background and Aims Atherosclerotic calcification is a powerful predictor of cardiovascular disease. This study aims to determine whether circulating levels of a local/systemic calcification inhibitor or a marker of bone formation correlate with measures of coronary or extracoronary calcification. Methods and Results Clinical computed tomography (...

Recently great advancements have been made in the field of intestinal tissue engineering. However, current in vitro intestinal tissue models have not yet successfully recapitulated all of the complex and dynamic physiological parameters of the intestinal tissue. In this chapter we will discuss the complexity of intestinal tissue structure, with our...

The dural venous sinuses play an integral role in draining venous blood from the cranial cavity. As a result of the sinuses anatomical location, they are of significant importance when evaluating the mechanopathology of traumatic brain injury (TBI). Despite the importance of the dural venous sinuses in normal neurophysiology, no mechanical analyses...

The meninges are membranous tissues which are pivotal in maintaining homeostasis of the central nervous system. Despite the importance of the cranial meninges in nervous system physiology and in head injury mechanics, our knowledge of the tissues’ mechanical behaviour and structural composition is limited. This systematic review analyses the existi...

In professional rugby, sports-related concussion (SRC) remains the most frequent time loss injury. Therefore, accurately diagnosing SRC and monitoring player recovery, through a multi-modal assessment process, is critical to SRC management. In this protocol study, we aim to assess SRC over multiple time points post-injury to determine the value of...

Since our previous reviews [1–3], the scope of applications of nanoparticles in medicine has significantly increased. Nanoalloys form a segment of the discussions on the wider scope of nanoparticles, which, in medicine, can offer unique advantages due to their chemical, physical, and biological properties. Superior properties of nanoparticles, such...

The rupture of atherosclerotic plaques is the prerequisite for adverse cardiovascular events. Calcification morphology plays a critical role in plaque stability, therefore accurate calcification classification is essential for favourable patient management. Blood biomarkers may be a worthwhile approach to stratify patients based on calcification ph...

Delivering therapeutics to disease sites is a challenge facing modern medicine. Nanoparticle delivery systems are of considerable interest to overcome this challenge, but these systems suffer from poor clinical translation. It is believed this is, in part, due to incomplete understanding of nanoparticle physico-chemical properties in vivo. To under...

The blood-brain barrier (BBB) protects the central nervous system (CNS) from toxins and homeostatic disruptions. However, this barrier also prevents nearly 100% of therapeutics from entering the CNS. The advent of nanoscale drug carriers, in particular metallic-based nanoparticles, shows significant promise to overcome this barrier. These nanoparti...

The blood–brain barrier (BBB) has a significant contribution to homeostasis and protection of the CNS. However, it also limits the crossing of therapeutics and thereby complicates the treatment of CNS disorders. To overcome this limitation, the use of nanocarriers for drug delivery across the BBB has recently been exploited. Nanocarriers can utiliz...

Treating diseases of the central nervous system (CNS) is complicated by the presence of the blood-brain barrier (BBB), a semipermeable boundary layer protecting the CNS from toxins and homeostatic disruptions. However, this layer also excludes almost 100% of therapeutics, impeding the treatment of CNS diseases. The advent of nanoparticles, in parti...

Purpose: To investigate the principles that govern ureteral stent failure by digitally and mechanically characterizing their luminal reduction in response to various extrinsic compression forces. To explore the relationship between ureteral stent "material area," "luminal area," and "cross-sectional area (CSA)" for resisting extrinsic compression...

The meninges are pivotal in protecting the brain against traumatic brain injury (TBI), an ongoing issue in most mainstream sports. Improved understanding of TBI biomechanics and pathophysiology is desirable to improve preventative measures, such as protective helmets, and advance our TBI diagnostic/prognostic capabilities. This study mechanically c...

Background: The urinary bladder and urethra comprise the lower urinary tracts. Pathological conditions that affect both structures necessitate reconstructive urological intervention with autologous tissue sources that cause neuromechanical and metabolic complications. Stem-cell therapies may offer an attractive alternative as they can replicate im...

Autologous gastrointestinal tissue is the gold standard biomaterial for urinary tract reconstruction despite its long-term neuromechanical and metabolic complications. Regenerative biomaterials have been proposed as alternatives; however many are limited by a poor host derived regenerative response and deficient supportive elements for effective ti...

Neuronal metal ions such as zinc are essential for brain function. In particular synaptic processes are tightly related to metal and protein homeostasis, for example through extracellular metal-binding proteins. One such protein is neuronal S100B, a calcium and zinc binding damage-associated molecular pattern (DAMP), whose chronic upregulation is a...

A local dyshomeostasis of zinc ions in the vicinity of amyloid aggregates has been proposed in Alzheimer's disease (AD) due to the sequestration of zinc in senile plaques. While an increase in zinc levels may promote the aggregation of amyloid beta (Aβ), increased brain zinc might also be beneficial rescuing some pathological alterations caused by...

Glaucoma is a common optic neuropathy characterized by retinal ganglion cell death. Elevated intraocular pressure (IOP), a key risk factor for glaucoma, leads to significant biomechanical deformation of optic nerve head (ONH) cells and tissues. ONH astrocytes respond to this deformation by transforming to a reactive, proliferative phenotype, which...

Objective: To evaluate the mechanical properties of gastrointestinal (GI) tissue segments and to compare them with the urinary bladder for urinary tract reconstruction. Methods: Urinary bladders and GI tissue segments were sourced from porcine models (n = 6, 7 months old [5 male; 1 female]). Uniaxial planar tension tests were performed on bladde...

Autologous gastrointestinal tissue has remained the gold-standard reconstructive biomaterial in urology for >100 years. Mucus-secreting epithelium is associated with lifelong metabolic and neuromechanical complications when implanted into the urinary tract. Therefore, the availability of biocompatible tissue-engineered biomaterials such as extracel...

Purpose: Cerebrospinal fluid pressure (CSFp) changes are involved or implicated in various ocular conditions including glaucoma, idiopathic intracranial hypertension, and visual impairment and intracranial pressure syndrome. However, little is known about the effects of CSFp on lamina cribrosa and retrolaminar neural tissue (RLNT) biomechanics, po...

Gelatinase zymography is a commonly used laboratory procedure; however, variability in sample loading and concentration reduce the accuracy of quantitative results obtained from this technique. To facilitate normalization of gelatinase activity by loaded protein amount, we developed a protocol using the trihalocompound 2,2,2-trichloroethanol to all...

This study compares the mechanical properties of excised carotid and femoral human plaques and also develops a predictor of these properties based on plaque composition. Circumferential planar tension tests were performed on 24 carotid and 16 femoral plaque samples. Composition was characterised using Fourier transform infrared spectroscopy. Stretc...

Purpose Scleral stiffening has been proposed as a treatment for glaucoma to protect the lamina cribrosa (LC) from excessive intraocular pressure–induced deformation. Here we experimentally evaluated the effects of moderate stiffening of the peripapillary sclera on the deformation of the LC. Methods An annular sponge, saturated with 1.25% glutarald...

Due to the limited number of experimental studies that mechanically characterise human atherosclerotic plaque tissue from the femoral arteries, a recent trend has emerged in current literature whereby one set of material data based on aortic plaque tissue is employed to numerically represent diseased femoral artery tissue. This study aims to genera...

Calcification is a marked pathological component in carotid artery plaque. Studies have suggested that calcification may induce regions of high stress concentrations therefore increasing the potential for rupture. However, the mechanical behaviour of the plaque under the influence of calcification is not fully understood. A method of accurately cha...

Varying degrees of calcification are present in most abdominal aortic aneurysms (AAAs). However, their impact on AAA failure properties and AAA rupture risk is unclear. The aim of this work is evaluate and compare the failure properties of partially calcified and predominantly fibrous AAA tissue and investigate the potential reasons for failure. Un...

The failure of endovascular treatments of peripheral arterial disease represents a critical clinical issue. Specialised data are required to tailor such procedures to account for the mechanical response of the diseased femoral arterial tissue to medical device deployment. The purpose of this study is to characterise the mechanical response of ather...

Recent experimental studies performed on human carotid plaques have focused on mechanical characterisation for the purpose of developing material models for finite element analysis without quantifying the tissue composition or relating mechanical behaviour to pre-operative classification. This study characterises the mechanical and biological prope...

Atherosclerosis is a cardiovascular disease that occurs within the walls of arteries and can result in a reduction of the lumen diameter. This reduction can cause a decrease in blood flow to the brain which can lead to a stroke event. Carotid angioplasty stenting (CAS) is a minimally invasive surgical treatment for stroke prevention and has been fo...

Computational models of diseased arteries are advancing rapidly, and a need exists to develop more accurate material models of human atherosclerotic plaques. However, intact samples for in vitro mechanical testing are not readily available. Most plaque samples are harvested from carotid endarterectomies where the geometries are not suitable for the...

This study assesses the suitability of developing a material for use in an experimental model of the carotid baroreceptors. Such a model could then be used in future studies to assess the impact of carotid artery stenting on hemodynamic stability. The material must exhibit a significant measurable electrical response to strain in a fashion analogou...

The development of atherosclerosis in the carotid bifurcation of the cardiovascular system has been the subject of much investigation. The carotid bifurcation is a prevalent area for atherosclerotic plaque build-up (Sakata et al., 1988). The performance of minimally invasive treatment of this plaque build-up has been below expectations. There is an...