Patrick S. Vaccaro

Inactivation of mitochondrial respiratory chain complex I leads mitochondrial nitric oxide synthase to become pro-oxidative

We recently demonstrated that mitochondrial nitric oxide synthase (mtNOS) functionally couples with mitochondrial respiratory chain complex I to produce nitric oxide [M.S. Parihar, R.R. Nazarewicz, E. Kincaid, U. Bringold, P. Ghafourifar, Association of mitochondrial nitric oxide synthase activity with respiratory chain complex I, Biochem. Biophys. Res. Commun. 366 (2008) 23-28]. The present report shows that inactivation of complex I leads mtNOS to become pro-oxidative. Our findings suggest a crucial role for mtNOS in oxidative stress caused by mitochondrial complex I inactivation.

Surgical correction of abdominal aortic coarctation and hypertension

Coarctations of the abdominal aorta are often associated with renal artery stenosis resulting in hypertension, which is commonly the presenting symptom. Controversy exists concerning the origin of these lesions, but there is general agreement that surgical intervention is the treatment of choice. We report four patients with abdominal aortic coarctation and concomitant renal artery stenosis who required aortoaortic bypass and appropriate bypass to the renal vessels. We advise total correction in one stage and proximal renal artery bypass from native aorta or iliac artery when it is technically feasible.

Methods for the Initiation and Maintenance of Human Endothelial Cell Culture

The culture of human endothelial cells for the in vitro investigation of the metabolic, synthetic, and physiologic functions of these cells has grown increas ingly common. Model systems investigating the pathogenesis of atherosclerosis are being developed. Methods for the initiation and maintenance of human en dothelial cell cultures are described. The roles of cryopreservation, microcar rier culturing, and roller bottle mass culturing are discussed.

Protein S deficiency in pregnancy

The case of a primigravid patient with protein S deficiency, a rare disorder resulting in recurrent venous thrombosis, was managed with prophylactic heparin therapy and elective pregnancy termination. Although rarely diagnosed, protein S deficiency may become more commonly identified with wider application of protein S assays.

Shortcomings of physical examination and impedance plethysmography in the diagnosis of lower extremity deep venous thrombosis.

Accuracy in the diagnosis of lower extremity deep venous thrombosis (DVT) by physical examination and impedance plethysmography (IPG) is reviewed. Physical examination proved unreliable in distinguishing patients with and without acute disease. Swelling in the leg was, however, more prevalent in patients with DVT. The sensitivity and specificity of IPG were less than those reported by other groups. Venography remains the most reliable diagnostic procedure in our institution.

Nitric oxide irreversibly inhibits cytochrome oxidase at low oxygen concentrations: Evidence for inverse oxygen concentration‐dependent peroxynitrite formation

The present study shows that nitric oxide (NO) irreversibly inhibits purified cytochrome oxidase in a reverse oxygen concentration‐dependent manner. The inhibition is dramatically protected by a peroxynitrite scavenger, suggesting that peroxynitrite is formed from the reaction of NO with cytochrome oxidase at low oxygen concentration, and that peroxynitrite is involved in irreversible cytochrome oxidase inactivation. Production of nitroxyl anion or superoxide was tested as potential mechanisms underlying the conversion of NO to peroxynitrite. A nitroxyl anion scavenger potently protected the irreversible inhibition, whereas a superoxide dismutase did not provide protective effect, suggesting that the peroxynitrite was formed from nitroxyl anion rather than the reaction of NO with superoxide.

Infrarenal aortic aneurysmectomy.

The complications of major vascular surgery are closely allied with intraoperative technical errors. Thus, in this article, surgical management is carefully described, with special stress given to those details in which complications can be avoided. The complications of infrarenal aortic aneurysmectomy are discussed, emphasizing incidence, cause, diagnosis, management, and results.

Natural History of the Great Saphenous Vein Stump Following Endovenous Laser Therapy

Background: Little is known about the ideal residual length of the great saphenous vein (GSV) stump and its potential role in complications such as acute deep venous thrombosis (DVT) and recanalization. This study was designed to learn about the natural history of the residual GSV stump length following endovenous laser treatment. Methods: Prospective data were collected from 50 limbs of 50 patients over an 11-month period. Clinical assessment and duplex ultrasound were performed preoperatively, at 24 hours and at 3 months after the procedure. Results: The residual GSV stump decreased in length from a mean of 15 mm at 24 hours to 13 mm at 3 months after the procedure. None of the patients developed acute DVT or proximal recanalization when the laser tip was positioned 28 mm distal to the saphenofemoral junction. Conclusion: Endovenous laser therapy of the GSV for symptomatic reflux is safe and effective. The residual GSV stump decreased in length over a 3-month period.

Traumatic Pseudoaneurysm in a Wrestler

An 18-year-old man sought treatment for a pulsatile mass in the medial distal thigh four years after he had sustained blunt trauma during a wrestling match. Investigation, which included magnetic resonance imaging and arteriography, showed the mass to be a pseudoaneurysm, which should be considered in the differential diagnosis of masses resulting from direct, blunt trauma. At exploration, a pseudoaneurysmic thrombus in the superficial femoral artery was evacuated and the vessel was repaired with an interposition graft of reversed saphenous vein, followed by complete recovery of the patient.

Iron and noncontrast magnetic resonance T2* as a marker of intraplaque iron in human atherosclerosis

OBJECTIVE Iron has been implicated in atherogenesis and plaque destabilization, whereas less is known about iron-related proteins in this disease. We compared ex vivo quantities with in vivo vessel wall T2*, which is a noncontrast magnetic resonance relaxation time that quantitatively shortens with increased tissue iron content. We also tested the hypothesis that patients with carotid atherosclerosis have abnormal T2* times vs controls that would help support a role for iron in human atherosclerosis. METHODS Forty-six patients undergoing carotid endarterectomy and 14 subjects without carotid disease were prospectively enrolled to undergo carotid magnetic resonance imaging. Ex vivo measurements were performed on explanted plaque and 17 mammary artery samples. RESULTS Plaques vs normal arteries had higher levels of ferritin (median, 7.3 [interquartile range (IQR), 4-13.8] vs 1.0 [IQR, 0.6-1.3] ng/mg; P < .001) and oxidized low-density lipoprotein (median, 0.17 [IQR, 0.12-0.30] vs 0.01 [IQR, 0.003-0.03] ng/mg; P < .001) as well as hepcidin (median, 8.7 [IQR, 4.6-12.4] vs 2.6 [IQR, 1.3-7.0] ng/mL; P = .03); serum hepcidin levels did not distinguish atherosclerosis patients from controls (median, 40.6 [IQR, 18.8-88.6] vs 33.9 [IQR, 17.6-55.2]; P = .42). Shorter in vivo T2* paralleled larger plaque volume (ρ = -.44; P = .01), and diseased arteries had shorter T2* values compared with controls (median, 17.7 ± 4.3 vs 23.0 ± 2.4 ms; P < .001). CONCLUSIONS Diseased arteries have greater levels of iron-related proteins ex vivo and shorter T2* times in vivo. Further studies should help define the role of T2* as a biomarker of iron and atherosclerosis.