Matthew E. Anderson

EGFR-Mediated Beclin 1 Phosphorylation in Autophagy Suppression, Tumor Progression, and Tumor Chemoresistance

Cell surface growth factor receptors couple environmental cues to the regulation of cytoplasmic homeostatic processes, including autophagy, and aberrant activation of such receptors is a common feature of human malignancies. Here, we defined the molecular basis by which the epidermal growth factor receptor (EGFR) tyrosine kinase regulates autophagy. Active EGFR binds the autophagy protein Beclin 1, leading to its multisite tyrosine phosphorylation, enhanced binding to inhibitors, and decreased Beclin 1-associated VPS34 kinase activity. EGFR tyrosine kinase inhibitor (TKI) therapy disrupts Beclin 1 tyrosine phosphorylation and binding to its inhibitors and restores autophagy in non-small-cell lung carcinoma (NSCLC) cells with a TKI-sensitive EGFR mutation. In NSCLC tumor xenografts, the expression of a tyrosine phosphomimetic Beclin 1 mutant leads to reduced autophagy, enhanced tumor growth, tumor dedifferentiation, and resistance to TKI therapy. Thus, oncogenic receptor tyrosine kinases directly regulate the core autophagy machinery, which may contribute to tumor progression and chemoresistance.

Rapid cortisol assays improve the success rate of adrenal vein sampling for primary aldosteronism.

Objective:We hypothesized that an adrenal vein sampling (AVS) algorithm incorporating rapid cortisol assays, which enables resampling of the adrenal veins, would improve the success rate by a team of radiologists. Summary Background Data:AVS is the most accurate means to localize aldosterone production in primary aldosteronism (PA). However, cannulation of the right adrenal vein (RAV) is difficult, and success is assumed from venography without the support of steroid assays. Furthermore, few institutions can assign all studies to 1 dedicated and experienced AVS interventional radiologist. Methods:Retrospective chart review of patients with PA at our university hospitals who underwent AVS. We compared results for 30 AVS studies incorporating rapid cortisol assays with 30 conventional AVS studies. Results:The success rate for the control period was 73% (22/30 studies). For the first 30 studies after incorporating rapid cortisol assay, the success rate increased to 97% (29/30 studies). Resampling the RAV was required for 2 studies, and prolonged sheath insertion did not cause any complications. Conclusions:High AVS success rates may be achieved by a team of interventional radiologists at 1 center using defined AVS protocols. Rapid cortisol assay allows for resampling of the RAV and improves AVS success rates.

Thrombolysis and Transjugular Intrahepatic Portosystemic Shunt Creation for Acute and Subacute Portal Vein Thrombosis

Catheter-based interventional therapy offers a safe and effective option for treatment of symptomatic portomesenteric venous thrombosis refractory to medical therapy. Various techniques and approaches have been described for thrombolysis and thrombectomy and re-establishing the portal venous flow for select populations. Early diagnosis and prompt treatment based on clinical presentation, imaging, and underlying anatomy are necessary to prevent long-term complications. This article describes various catheter-based approaches for treatment of acute and subacute portal vein thrombosis.

Multidetector CT Angiography of Infrainguinal Arterial Bypass

Infrainguinal arterial bypass (IGAB) surgery is commonly performed in patients with claudication, critical limb ischemia, or other arterial problems in the lower extremities. An IGAB is constructed from different materials depending on the anatomy of the lesion and the availability of an autogenous vein. The ideal material for IGAB is the greater saphenous vein, especially for distal below-knee bypass. In patients with no available autogenous vein, IGAB can be performed by using different prosthetic materials or biologic grafts. After the surgery, periodic surveillance is performed with duplex ultrasonography and clinical assessment of peripheral pulses and ankle-brachial indexes. If complications are detected, further work-up is performed with conventional arteriography, multidetector computed tomographic (CT) angiography, or magnetic resonance angiography. CT angiography has become a powerful tool for assessing the potential early and late complications of IGAB and for planning further therapy in a fast, reliable, and noninvasive manner.

Ureteroarterial Fistula: Diagnosis and Management

OBJECTIVE Ureteroarterial fistula (UAF) is an uncommon condition with only approximately 150 cases reported in the literature. Patients typically present with hematuria in the setting of prolonged ureteral stenting, prior pelvic surgery, malignancy, or radiation. Presentation can vary from intermittent hematuria to life-threatening hemorrhagic shock. CONCLUSION Recognizing this condition in a prototypical patient is essential for accurate diagnosis and management. Angiography yields the highest diagnostic benefit, and arterial stent-graft placement is the treatment of choice.

Detection of ectopic parathyroid adenoma by early Tc-99m sestamibi imaging

Localization of Tc-99m sestamibi (MIBI) by parathyroid adenomas (PA) is well known. Typically the radionuclide washes out slowly from the PAs located in the neck. Rapid washout from some PAs has been reported. Various hypotheses have been postulated for slow and rapid clearance of MIBI from PAs, located in the neck. However, the washout of MIBI from ectopic parathyroid adenoma (EPA) in not well reported. We present a case of EPA with rapid washout of MIBI. Hence, early MIBI imaging plays an important role in the evaluation of EPA.

Anatomic and radiologic review of chronic mesenteric ischemia and its treatment

Chronic mesenteric ischemia (CMI) is a vascular occlusive disease process that generally affects the elderly population. Clinical presentation occurs when two of the three mesenteric arteries are affected and includes non-specific abdominal pain and weight loss. The most common cause of CMI is atherosclerotic arterial occlusion. The aim of this review is to present the vascular anatomy of the mesenteric arterial circulation including the different collateral pathways. The imaging findings and the different treatment options with a brief review of the literature is presented.

Pulmonary arteriovenous malformations: endovascular therapy

Pulmonary arteriovenous malformations (PAVM) are abnormal direct communications between the branches of pulmonary arteries and veins, and are often seen in patients with hereditary hemorrhagic telangiectasia (HHT). If untreated, the right to left shunt can result in symptoms of hypoxemia, paradoxical emboli to the left side circulation, stroke and intracranial abscess. Endovascular therapy is a minimally invasive outpatient based treatment wherein the feeding artery to the PAVM is occluded with coils or plugs or a combination of both and is associated with minimal morbidity and no mortality. In this manuscript, we will review the indications and contraindications for endovascular therapy, pre-procedural work up, procedure technique and variations, complications, and outcomes.

Peripheral Arterial Disease in Hemodialysis Access

Peripheral artery disease (PAD) is a major health concern and its incidence increases with age. End stage renal disease is a major risk factor for developing PAD and is associated with a remarkably high incidence of cardiovascular morbidity and mortality [1]. In patients with end stage renal disease (ESRD), the estimated prevalence of PAD ranges between 17 and 48 % [2, 3]. Data on the prevalence of clinically significant upper extremity PAD are scarce, however, a 10–20 fold lower incidence may be appreciated compared to that affecting the lower extremity [4].

Spontaneous portosystemic shunts in noncirrhotic patients presenting with encephalopathy

Portosystemic shunts (PSS) are common in patients with chronic liver disease and portal hypertension, however, their occurrence in noncirrhotic individuals is likely under appreciated. Patients may present with symptoms of hepatic encephalopathy and/or gastrointestinal bleeding and undergo extensive work up for liver disease to no avail. Often, these patients suffer for years with accruing medical expenses and numerous hospitalizations related to repeated episodes of encephalopathy. The underlying cause may go undiagnosed or misdiagnosed as occult hepatic dysfunction or even a neuropsychological disorder. In many cases, abdominal CT imaging demonstrates the abnormal portosystemic connection well before it is recognized as the cause of symptoms. In this brief report, we discuss three cases presenting with symptoms of encephalopathy and report successful management with endovascular occlusion of the portosystemic shunts.