Thoracic aortic aneurysm repair using the elephant trunk technique and associated complications.

The frozen elephant trunk stent has greatly facilitated the repair of elective and emergency arch and proximal descending thoracic aortic aneurysms and dissections. As one of the few tertiary hospitals that routinely inserts and images the floating and frozen elephant trunk grafts, we aim to provide an up-to-date illustration of the contrasting methods of elephant trunk thoracic aortic aneurysm repair through a computed tomography (CT) review and detail the common radiological interpretation pitfalls in addition to the most significant associated complications.

CT of transposition of the great arteries in adults.

Transposition of the great arteries is one of the most common cyanotic congenital heart diseases. It is characterised by an abnormal connection of the ventricles and great arteries, so that the aorta arises from the morphological right ventricle and the pulmonary artery arises from the morphological left ventricle. Historically, as with many congenital heart diseases, patients with transposition of the great arteries had poor life expectancy. Advances in surgical and medical management have resulted in patients surviving into adulthood. As these patients are living longer, they will be encountered more frequently in practice. The purpose of this article is to familiarise the general radiologist with the expected postoperative anatomy, and the appearance on cross-sectional imaging as well as the long-term complications in this group of patients.

Cross-sectional imaging of the Fontan circuit in adult congenital heart disease.

The Fontan circuit is the result of a palliative surgical procedure that is performed in patients with a functionally single ventricle cardiac anomaly. The success of this operation has resulted in an increasing population of adults with this anatomy and physiology. The purpose of this article is to familiarize the general radiologist with the expected anatomy and cross-sectional imaging findings, highlight special imaging considerations, and examine the common complications that are encountered in this group of patients.

Peripheral limb vascular malformations: an update of appropriate imaging and treatment options of a challenging condition.

Peripheral vascular malformations encompass a wide spectrum of lesions that can present as an incidental finding or produce potentially life- or limb-threatening complications. They can have intra-articular and intraosseous extensions that will result in more diverse symptomology and present greater therapeutic challenges. Developments in classification, imaging and interventional techniques have helped to improve outcome. The onus is now placed on appropriate detailed preliminary imaging, diagnosis and classification to direct management and exclude other more common mimics. Radiologists are thus playing an increasingly important role in the multidisciplinary teams charged with the care of these patients. By fully understanding the imaging characteristics and image-guided procedures available, radiologists will be armed with the tools to meet these responsibilities. This review highlights the recent advances made in imaging and the options available in interventional therapy.

Update on imaging of non-infectious musculoskeletal complications of HIV infection.

Acquired immunodeficiency syndrome (AIDS) results from infection with human immunodeficiency virus (HIV), producing an immunodeficient state and severe pathology across multiple organ systems. Musculoskeletal involvement is particularly prevalent in this population with both infectious and non-infectious complications encountered, but it is suggested that the latter will affect 72% of HIV-infected individuals. In this review we aim to provide an update on the imaging characteristics of the non-infectious manifestations. The conditions include HIV-related arthritis as well as various malignancies, myositis, anaemia, osteonecrosis, rhabdomyolysis, hypertrophic osteoarthropathy and therapy-related side effects. For the clinician, the diagnostic challenge lies in differentiating disease-related symptoms from therapy-related side effects, particularly when clinical and laboratory features can be non-specific. This is especially difficult following the widespread introduction of highly active anti-retroviral therapy (HAART). Imaging investigations and MRI in particular have proven vital for facilitating early diagnosis and enabling prompt treatment. Furthermore, wider availability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has allowed whole-body assessment for staging and treatment response of malignancy. Understanding the pathogenesis of the various conditions and recognising their imaging features is essential for the clinical radiologist.

Imaging of thoracic aortic disease.

Aortic pathology can be more complex to understand on imaging than is initially appreciated. There are a number of imaging modalities that provide excellent assessment of aortic pathology and enable the accurate monitoring of disease. This review discusses the imaging of the most common disease processes that affect the aorta in adults, with the primary focus being on CT and MRI.

Graphene double-layer capacitor with ac line-filtering performance.

Electric double-layer capacitors (DLCs) can have high storage capacity, but their porous electrodes cause them to perform like resistors in filter circuits that remove ripple from rectified direct current. We have demonstrated efficient filtering of 120-hertz current with DLCs with electrodes made from vertically oriented graphene nanosheets grown directly on metal current collectors. This design minimized electronic and ionic resistances and produced capacitors with RC time constants of less than 200 microseconds, in contrast with ~1 second for typical DLCs. Graphene nanosheets have a preponderance of exposed edge planes that greatly increases charge storage as compared with that of designs that rely on basal plane surfaces. Capacitors constructed with these electrodes could be smaller than the low-voltage aluminum electrolyte capacitors that are typically used in electronic devices.

Dynamic ultrasound assessment in the diagnosis of intra-articular entrapment of the biceps tendon (hourglass biceps): A preliminary investigation.

BACKGROUND: The hourglass biceps, an intra-articular entrapment of the long head of the biceps (LHB), is a possible diagnosis in cases of shoulder pain associated with loss of passive elevation. PURPOSE: The objective of this study is to investigate the role of dynamic ultrasound (U/S) in determining the diagnosis of the hourglass biceps lesion. MATERIALS AND METHODS: A prospective cohort of 16 patients with the clinical suspicion of an hourglass lesion, a preoperative ultrasound, and a confirmed hourglass LHB at surgery, were included in the study. Eight patients had preoperative dynamic ultrasound assessment of the LHB, and eight had standard ultrasound investigations and served as a control group. RESULTS: Dynamic ultrasound accurately diagnosed an hourglass biceps in three out of eight cases. LHB hypertrophy was demonstrated in five out of eight cases with U/S and three out of eight cases with standard U/S. All patients were treated by excision of the intra-articular portion of the LHB, 15 by bipolar tenotomy, and one by LHB tenodesis. CONCLUSIONS: Dynamic ultrasound shows promise in improving the accuracy in diagnosis of LHB hypertrophy and the Hourglass lesion. LEVEL OF EVIDENCE: III (Consecutive case-control study investigating a diagnostic test).

Changes of bone metabolism in seven patients with Gaucher disease treated consecutively with imiglucerase and miglustat.

Bone manifestations are frequent in Gaucher disease (GD), the most prevalent lysosomal storage disorder. Currently, therapy with enzyme replacement (ERT) or substrate reduction (SRT) is available. We investigated changes of laboratory parameters associated with bone metabolism in GD patients switching from ERT to SRT. Seven GD patients consecutively treated with ERT and SRT were studied. All patients had different degrees of bone involvement. Laboratory results were acquired at the time of change from ERT to SRT (0 months) and while on SRT (6 months, 12-18 months). Markers of GD activity remained stable or showed statistically insignificant increases. Six patients had stable skeletal manifestations and reported no bone-associated symptoms. One patient presented progressive bone manifestations on magnetic resonance imaging and experienced increasing bone pain. Osteocalcin, alkaline phosphatase, and C-terminal telopeptide of collagen I were initially within the lower part of the normal range and decreased during SRT (alkaline phosphatase P = 0.0169, osteocalcin nonsignificant, C-terminal telopeptide of collagen I nonsignificant). Tartrate-resistant acid phosphatase 5b was initially normal or slightly increased, and macrophage colony-stimulating factor was within the normal lower range; both parameters remained stable. Interleukin-6 was elevated only in the patient with progressive bone disease. Macrophage inflammatory protein 1alpha (MIP-1alpha) was elevated without change after switching to SRT. MIP-1beta was within the normal range, and no values were above 85 ng/mL, indicative of active skeletal disease. From a clinical and metabolic point of view, most skeletal manifestations and bone-associated laboratory parameters remain stable after switch from ERT to SRT.

The radiological manifestations of sickle cell disease.

Sickle cell disease (SCD) is an inherited abnormality of the beta-globin chain, which causes a spectrum of haemolytic anaemias. Clinical manifestations in SCD include anaemia, jaundice, recurrent vaso-occlusive crises, and infections (particularly by encapsulated bacteria) due to functional asplenia and cerebrovascular accidents. Radiological investigations play a critical role both in the diagnosis and in the primary prevention of the complications of SCD.

Inhibition of insulin receptor isoform-A signalling restores sensitivity to gefitinib in previously de novo resistant colon cancer cells.

Resistance to antiepidermal growth factor (EGFR) strategies is an emerging clinical problem. Using human colorectal cancer (CRC) cells, we evaluated the involvement of the insulin receptor isoform-A (InsR-A) in de novo resistance to gefitinib, an EGFR tyrosine kinase inhibitor. Challenging the EGFR positive LoVo cells with gefitinib (1 microM) resulted in a small ( approximately 18%) inhibition of cell growth and although a modest reduction in phospho (p)EGFR Tyr845 was seen, pEGFR at residues -Tyr1068 and -Tyr1173 were unchanged. LoVo cells produced unprocessed pro-IGF-1R protein, substantial levels of IGF-II mRNA and mature InsR protein, consisting mainly of the InsR-A isoform. Insulin and IGF-II promoted cell growth and pEGFR Tyr845, Tyr1068 and Tyr1173 activity and conversely, the insulin-like growth factor-1 receptor (IGF-1R)/InsR inhibitor ABDP (1 muM) inhibited growth and reduced pEGFR activity at all three tyrosine residues. pInsR and pAkt levels were increased after gefitinib treatment. Blocking of pInsR with ABDP enabled gefitinib to markedly reduce pEGFR Tyr845, Tyr1068 and Tyr1173. Short-term gefitinib/ABDP dual treatment was more effective than either agent alone and chronic exposure to this combination resulted in total cell loss after 9 weeks, preventing acquisition of resistance to ABDP. LoVo cells with acquired resistance to ABDP were acutely sensitive to gefitinib. We concluded that InsR-A reduces sensitivity to gefitinib in LoVo CRC cells, thus its co-targeting alongside EGFR can improve the anti-tumour effect of gefitinib.

Thermal desorption of hydrogen from carbon nanosheets.

Carbon nanosheets are a unique nanostructure that, at their thinnest configuration, approach a single freestanding graphene sheet. Temperature desorption spectroscopy (TDS) has shown that the hydrogen adsorption and incorporation during growth of the nanosheets by radio frequency plasma-enhanced chemical vapor deposition are significant. A numerical peak fitting to the desorption spectra (300-1273 K) via the Polanyi-Wigner equation showed that desorption followed a second order process, presumably by the Langmuir-Hinshelwood mechanism. Six peaks provide the best fit to the TDS spectra. Surface desorption activation energies were determined to be 0.59, 0.63, and 0.65 eV for the external graphite surface layers and 0.85, 1.15, and 1.73 eV for desorption and diffusion from the bulk. In contrast to TDS data from previously studied a-C:H films [Schenk et al. J. Appl. Phys. 77, 2462 (1995)], a greater amount of hydrogen bound as sp(2) hybridized carbon was observed. A previous x-ray diffraction study of these films has shown a significant graphitic character with a crystallite dimension of L(a)=10.7 nm. This result is consistent with experimental results by Raman spectroscopy that show as-grown carbon nanosheets to be crystalline as commercial graphite with a crystallite size of L(a)=11 nm. Following TDS, Raman data indicate that the average crystallite increased in size to L(a)=15 nm.

The association of aldose reductase gene (AKR1B1) polymorphisms with diabetic neuropathy in adolescents.

AIMS: Variants in the aldose reductase gene (AKR1B1) have been implicated in the development of diabetic retinopathy and nephropathy, with the most convincing data identifying a (CA)(n) repeat microsatellite allele (Z-2), which has a functional role in gene expression. In this study the association between polymorphisms in the AKR1B1 gene and diabetic neuropathy was investigated. METHODS: The pupillary response to light was used as the major outcome in this study along with abnormal hot thermal threshold. Three hundred and sixty-three adolescents underwent genotyping of the AKR1B1 gene. The microsatellite (CA)(n) repeat was sequenced and two single nucleotide polymorphisms, -106C-->T and -12C-->G, were investigated by restriction fragment length polymorphism. RESULTS: Seventy-six percent of participants had pupillary abnormalities (45% with two, 15% with three abnormalities). Presence of the Z-2/Z-2 genotype increased the risk nearly three-fold for pupillary abnormalities [odds ratio (OR) 3.02, 95% confidence interval (CI) 1.14, 7.98). The susceptibility genotypes (Z-2/Z-2 with -106C/-106C, Z-2/Z with -106C/-106C or Z/Z with -106C/-106C) were associated with resting pupil diameter abnormalities when compared with the protective genotypes (Z+2/Z+2 or -106T/-106T) (OR 2.83, 95% CI 1.25, 6.41). The combination of Z+2/-106T reduced the risk of abnormal heat discrimination (OR 0.48, 95% CI 0.23, 0.99). CONCLUSIONS: In this study we have shown that Z-2/Z-2 genotype is significantly associated with the development of pupillary abnormality, an early indicator of diabetic autonomic neuropathy, in adolescent Australian patients with Type 1 diabetes.

Case report: MR imaging features of endometriosis at the umbilicus.

The radiological features of extrapelvic endometriosis at the umbilicus with large ovarian endometriomas are described. In this patient, the umbilical lesion appears as hypointense on T(1) weighted and T(2) weighted MR images. The MR characteristics of endometriosis at the umbilicus are compared with those found within the pelvis.

Position of nuclear medicine modalities in the diagnostic work-up of breast cancer.

Breast tumors can be imaged by different modalities: mammography is the most widely used technique because of its diagnostic value, patient compliance and low costs. Some techniques such as ultrasound (US) are often indicated, while others, such as digital mammography and magnetic resonance imaging (MRI) are still under evaluation and seem to be very promising. Among the nuclear medicine techniques breast scintigraphy with (99m)Tc-labelled lipophilic cations (SestaMIBI or tetrofosmin), positron emission tomography (PET) with 18F-2-deoxy-2-fluoro-D-glucose (FDG) have been evaluated in many clinical trials. At present breast scintigraphy has limited applications due to its poor spatial resolution, which has a minimum of 8 mm. It is questionable whether single photon emission tomography (SPECT) can offer any substantially better information on the breast; however, SPECT is more accurate in detecting axillary lymph nodes. Recent approaches using breast dedicated collimators and cameras have greatly improved the SPECT resolution and sensitivity. The most interesting technique offered by nuclear medicine today are PET and lymphoscintigraphy with the intraoperative detection of handled gamma probe. The sentinel node detection has achieved a large consensus of reliability and at present it has an important place in the clinical management. In the same time many authors have acknowledged the value of PET in the differential diagnosis of breast lesions and in locoregional staging, since breast cancer is strongly avid for glucose. PET demonstrated also its efficacy in detecting axillary lymph node metastases. Even in some clinical trials its accuracy proved nearly comparable to that of lymphoscintigraphy with sentinel node biopsy, other studies showed that PET scanning does not currently have adequate spatial resolution to detect both micro- and small macrometastatic disease in axillary lymph nodes. The added value of PET in breast cancer staging is that with a single examination PET allows the characterisation of breast lesions, in addition to complete viewing of the entire body. Whole-body PET may substitute other diagnostic assessments by examining the various regions of potential tumour spread. The current diagnostic work-up for pre- and postoperative staging includes various examinations: chest X-rays, US of the abdomen, mammography of the contralateral breast. Bone scintigraphy with (99m)Tc-diphosphonates and laboratory tests can also be considered in women with large tumors or in symptomatic patients. Computed tomography (CT) and MRI may be used in order to resolve particular diagnostic problems. The current application of some of these modalities depends on the risk of the single patient of developing metastatic spread, which is revealed by a number of prognostic parameters of tumor aggressiveness and of course, clinical stage. Bone scintigraphy and PET may be useful in monitoring therapy response and in detecting tumour relapses during follow-up. In particular PET guided by tumor markers measurements shows to detect more lesions than other non nuclear medicine modalities.

AZD7545, a novel inhibitor of pyruvate dehydrogenase kinase 2 (PDHK2), activates pyruvate dehydrogenase in vivo and improves blood glucose control in obese (fa/fa) Zucker rats.

PDH (pyruvate dehydrogenase) is a key enzyme controlling the rate of glucose oxidation, and the availability of gluconeogenic precursors. Activation of PDH in skeletal muscle and liver may increase glucose uptake and reduce glucose production. This study describes the properties of AZD7545, a novel, small-molecule inhibitor of PDHK (PDH kinase). In the presence of PDHK2, AZD7545 increased PDH activity with an EC(50) value of 5.2 nM. In rat hepatocytes, the rate of pyruvate oxidation was stimulated 2-fold (EC(50) 105 nM). A single dose of AZD7545 to Wistar rats increased the proportion of liver PDH in its active, dephosphorylated form in a dose-related manner from 24.7 to 70.3% at 30 mg/kg; and in skeletal muscle from 21.1 to 53.3%. A single dose of 10 mg/kg also significantly elevated muscle PDH activity in obese Zucker (fa/fa) rats. Obese, insulin-resistant, Zucker rats show elevated postprandial glucose levels compared with their lean counterparts (8.7 versus 6.1 mM at 12 weeks old). AZD7545 (10 mg/kg) twice daily for 7 days markedly improved the 24-h glucose profile, by eliminating the postprandial elevation in blood glucose. These results suggest that PDHK inhibitors may be beneficial agents for improving glucose control in the treatment of type 2 diabetes.