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1.
Australas J Ultrasound Med ; 26(1): 5-12, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36960142

ABSTRACT

Introduction: Ultrasound measurements of the aorta are typically taken in the axial plane, with the transducer perpendicular to the aorta, and diameter measurements are obtained by placing the callipers from the anterior to the posterior wall and the transverse right to the left side of the aorta. While the 'conventional' anteroposterior walls in both sagittal and transverse plains may be suitable for aneurysms with less complicated geometry, there is controversy regarding the suitability of this approach for complicated, particularly tortuous aneurysms, as they may offer a more challenging situation. Previous work undertaken within our research group found that when training inexperienced users of ultrasound, they demonstrated more optimal calliper placement to the abdominal aorta when approached from a decubitus window to obtain a coronal image compared to the traditional ultrasound approach. Purpose: To observe the level of agreement in real-world reporting between computed tomography (CT) and ultrasound measurements in three standard planes; transverse AP, sagittal AP and coronal (left to right) infra-renal abdominal aortic aneurysm (AAA) diameter. Methodology: This is a retrospective review of the Otago Vascular Diagnostics database for AAA, where ultrasound and CT diameter data, available within 90 days of each other, were compared. In addition to patient demographics, the infrarenal aorta ultrasound diameter measurements in transverse AP and sagittal AP, along with a coronal decubitus image of the aorta was collected. No transverse measurement was performed from the left to the right of the aorta. Results: Three hundred twenty-five participants (238 males, mean age 76.4 ± 7.5) were included. Mean ultrasound outer to the outer wall, transverse AP and sagittal AP diameters were 48.7 ± 10.5 mm and 48.9 ± 9.9 mm, respectively. The coronal diameter measurement of the aorta from left to right was 53.9 ± 12.8 mm in the left decubitus window. The mean ultrasound max was 54.3 ± 12.6 mm. The mean CT diameter measurement was 55.6 ± 12.7 mm. Correlation between the CT max and ultrasound max was r 2 = 0.90, and CT with the coronal measurement r 2 = 0.90, CT and AP transverse was r2=0.80, and CT with AP sagittal measurement was r 2 = 0.77. Conclusion: The decubitus ultrasound window of the abdominal aorta, with measurement of the coronal plane, is highly correlated and in agreement with CT scanning. This window may offer an alternative approach to measuring the infrarenal abdominal aortic aneurysm and should be considered when performing surveillance of all infra-renal AAA.

2.
Eur J Vasc Endovasc Surg ; 64(4): 377-386, 2022 10.
Article in English | MEDLINE | ID: mdl-35667596

ABSTRACT

OBJECTIVE: Reflux within the superficial microvenous network may play a critical role in the development of skin changes which can be associated with chronic venous insufficiency. This study aimed to determine if near infrared fluorescence (NIRF) imaging could be used to accurately determine superficial venous reflux in the leg. METHODS: A total of nine limbs were examined ex vivo from patients undergoing limb amputation for peripheral arterial disease. Cannulation of the distal great saphenous vein was used to sequentially perform Xray contrast enhanced venography, NIRF imaging, and venous corrosion casts. RESULTS: Fluorescence imaging visualised a range of different microvenous reflux patterns ex vivo, which were generally not evident by Xray venography but were consistent with retrograde resin vascular casts. These included both focal and diffuse regions of fluorescence within the skin and, consistent with previous observations, the vascular casts indicated that regions of venous reflux were typically associated with incompetent valves. CONCLUSION: The findings from this study suggest a potential method for investigating early stage superficial venous disease, prior to the appearance of visible signs of advanced venous disease, such as skin changes. However, further studies are required to confirm the in vivo clinical utility of these observations.


Subject(s)
Leg , Venous Insufficiency , Humans , Leg/blood supply , Saphenous Vein/diagnostic imaging , Femoral Vein , Optical Imaging
3.
J Clin Endocrinol Metab ; 94(2): 654-61, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19001514

ABSTRACT

OBJECTIVE: The clinically used somatostatin analogs, octreotide and lanreotide, act primarily by binding to somatostatin receptor 2 (sst2). In contrast, the novel multireceptor ligand pasireotide (SOM230) binds with high affinity to somatostatin receptor subtypes sst1, sst2, sst3, and sst5. SOM230 is currently under clinical evaluation for treatment of acromegaly, Cushing's disease, and octreotide-resistant carcinoid tumors. However, the effects of SOM230 on internalization and postendosomal sorting of individual human somatostatin receptor subtypes have not been determined so far. RESULTS: Here we show that SOM230 was less potent than octreotide in inducing internalization and signaling of sst2 receptors expressed in human embryonic kidney cells. In contrast, SOM230 was more potent than octreotide in inducing internalization and signaling of sst3 and sst5 receptors. Both SOM230 and octreotide stimulated a rapid down-regulation of sst3 but not of sst2 or sst5 receptors. SOM230 and octreotide profoundly differed in their patterns of sst2-stimulated beta-arrestin mobilization. Whereas octreotide-mediated receptor activation led to the formation of stable complexes facilitating the internalization of sst2 and beta-arrestin-2 into the same endocytic vesicles, SOM230-mediated receptor activation led to the formation of unstable complexes that dissociated at or near the plasma membrane. Consequently, sst2 receptors recycled rapidly to the plasma membrane after endocytosis in SOM230-treated cells, but not in octreotide-treated cells. CONCLUSION: We show that SOM230 modulates somatostatin receptor trafficking in a manner clearly distinct from octreotide and somatostatin. These findings may provide an explanation for the differential regulation of somatostatin receptor responsiveness during long-term administration of stable somatostatin analogs.


Subject(s)
Octreotide/pharmacology , Receptors, Somatostatin/metabolism , Somatostatin/analogs & derivatives , Antineoplastic Agents, Hormonal/pharmacology , Cells, Cultured , Endocytosis/drug effects , Extracellular Signal-Regulated MAP Kinases/metabolism , Humans , Phosphorylation/drug effects , Protein Binding/drug effects , Protein Transport/drug effects , Somatostatin/pharmacology
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