Dynamic geometry and wall thickness of the aortic neck of abdominal aortic aneurysms with intravascular ultrasonography

BACKGROUND: It is commonly assumed that the aortic wall deforms uniformly and has uniform wall thickness about the circumference. The purpose of this study was to evaluate the aortic wall motion and thickness in the infrarenal aortic neck of patients with abdominal aortic aneurysms who were undergoing endovascular repair (EVAR) and to compare the dynamic measurements of intravascular ultrasonography with the static measurements of computed tomographic angiography (CTA). METHODS: A total of 25 patients were evaluated before surgery with CTA and three-dimensional reconstructions on a Vitrea workstation, followed by intraoperative assessment of the proximal aortic neck with intravascular ultrasonography (IVUS) before EVAR. Infrarenal aortic neck dimensions on CTA were obtained at 1-mm intervals, but for the purposes of this study all dimensions on CTA were obtained 1 cm below the lowest renal artery. IVUS analysis of the proximal aortic neck was obtained with a 10-second recorded data loop of aortic wall motion. A Digital Imaging and Communications in Medicine viewer was used to view the recorded loop of aortic movement, and each image was captured and then evaluated with a SCION PCI Frame Grabber to determine aortic dimensions and wall thickness. IVUS diameters (250 measurements of each aorta) were recorded through a full continuous cardiac cycle from the epicenter of the lumen (maintaining the left renal vein in its normal anatomic configuration) in an anteroposterior (AP) direction in the area of greatest wall movement and 90 degrees perpendicular to this direction (lateral movement). RESULTS: There was significant variation in infrarenal aortic wall movement about the circumference, with 1.7 +/- 0.6 mm (range, 0.6-2.7 mm) displacement in the AP direction and 0.9 +/- 0.5 mm (range, 0.3-1.5 mm) displacement in the lateral direction (P < .001). Aortic wall thickness was greater in the region of increased AP wall motion than in the area of lesser lateral wall motion (2.3 +/- 0.6 mm vs 1.2 +/- 0.3 mm; P < .001). There was no difference between the IVUS and CTA aortic neck measurements (25.5 vs 25.6 mm; not significant) during the midpoint of the cardiac cycle of IVUS. However, at peak systole, IVUS recorded a greater diameter than CTA (26.4 vs 25.6 mm; P < .001), and at end-diastole, IVUS recorded a smaller diameter than CTA (24.7 vs 25.6 mm; P = .01). CONCLUSIONS: The infrarenal neck of aortic aneurysms deforms anisotropically during the cardiac cycle. The greatest displacement is in the AP direction and corresponds with a significantly greater wall thickness in this area. The magnitude of cyclic change in aortic diameter can be as high as 11%. Further evaluation of proximal aortic neck wall motion after EVAR is warranted to determine the interaction of various stent designs and the aortic wall.     

Highly efficient ligands for dihydrofolate reductase from Cryptosporidium hominis and Toxoplasma gondii inspired by structural analysis

The search for effective therapeutics for cryptosporidiosis and toxoplasmosis has led to the discovery of novel inhibitors of dihydrofolate reductase (DHFR) that possess high ligand efficiency: compounds with high potency and low molecular weight. Detailed analysis of the crystal structure of dihydrofolate reductase-thymidylate synthase from Cryptosporidium hominis and a homology model of DHFR from Toxoplasma gondii inspired the synthesis of a new series of compounds with a propargyl-based linker between a substituted 2,4-diaminopyrimidine and a trimethoxyphenyl ring. An enantiomerically pure compound in this series exhibits IC50 values of 38 and 1 nM against C. hominis and T. gondii DHFR, respectively. Improvements of 368-fold or 5714-fold (C. hominis and T. gondii) relative to trimethoprim were generated by synthesizing just 14 new analogues and by adding only a total of 52 Da to the mass of the parent compound, creating an efficient ligand as an excellent candidate for further study.     

Use of the Vectra polyetherurethaneurea graft for dialysis access in HIV-positive patients with end-stage renal disease

The primary objective of this study was to establish the safety, efficacy, infection rate, and patency of the Vectra graft (polyetherurethaneurea) for dialysis access in patients diagnosed with human immunodeficiency virus (HIV) and end-stage renal disease. The Vectra graft has a unique self-sealing property; therefore we hypothesize that these patients will have fewer infections. A Vectra graft was implanted in 30 consecutive HIV-positive patients without sufficient veins for an autologous fistula. These surgeries were carried out over a 2.5-year period. Primary graft patency was 42% at 12 months and 3 (10%) of the grafts developed infection. This rate of graft infection was less (10% vs 45%) than both our prior experience and published reports using polytetrafluorothene bridge grafts. The unique self-sealing property of the Vectra graft minimizes the development of perigraft hematoma with repetitive needle cannulation and in the immunosuppressed HIV-positive patient, may account for the observed decrease in dialysis access infection.     

Dermoscopy to Identify Dermal Thinning

Biopsying of children is often difficult to accomplish and traumatic. Consequently, techniques that avert biopsy are welcome in children. We describe the use of handheld dermoscopy for confirmation of the diagnosis of lesions with dermal thinning, including focal dermal hypoplasia, aplasia cutis, and striae. The major advantage of this technique is rapid diagnosis in the absence of a surgical procedure.     

Role of Sirolimus in Advanced Kaposiform Hemangioendothelioma

Kaposiform hemangioendothelioma (KHE) is an infiltrative vascular tumor that classically presents in infancy. Management typically focuses on treating Kasabach–Merritt phenomenon (KMP), a disorder of severe and at times life‐threatening platelet trapping. However, the morbidity of KHE extends beyond KMP. The infiltrative nature of the tumor can lead to long‐term disability and often makes complete surgical resection impossible. We report the case of a 10‐year‐old boy with a KHE of his right distal thigh who was unable to walk without assistance due to fibrotic change and right knee contracture. He had no laboratory evidence of KMP at the time of representation. Rapamycin was started in hopes of reducing the tumor burden. Within 2 months of therapy, fibrotic areas softened, his contracture nearly resolved, and there was marked improvement in his mobility. Rapamycin has been previously reported to be effective in managing cases of KHE complicated by KMP. Our report emphasizes the role for rapamycin in the treatment of KHE in the absence of KMP through the inhibition of vasculogenesis and fibrotic pathways.     

Giant proliferating trichilemmal cyst arising from a nevus sebaceus growing for 30 years

Nevus sebaceus of Jadassohn, a congenital cutaneous hamartoma, has the potential to develop into various epidermal adnexal‐origin neoplasms. While the most common neoplasms are trichoblastoma or syringocystadenoma, proliferating trichilemmal cysts are exceptionally rare. We report a case of a 63‐year‐old Cuban male with a giant proliferating trichilemmal cyst arising from a nevus sebaceus on the right shoulder which had been growing for 30 years. Proliferating trichilemmal cysts arising from nevus sebaceus cases are difficult to diagnose clinically and histologically as they are very rare and have not been defined by exact diagnostic criteria. Our case creates awareness of this particular tumor in nevus sebaceus and shares clinical and histological diagnostic information that can be used to make a proper diagnosis.     

Post‐Chikungunya Rheumatic Disease in a 13‐Year‐Old Boy

Chikungunya is a mosquito‐borne viral infection that causes an acute febrile illness and can result in acute or chronic musculoskeletal disease. A 13‐year‐old boy presented with post‐Chikungunya rheumatic disease featuring connective tissue disease signs including digital ulcerations, cuticular dystrophy, dilated capillary loops, and digital tapering.