Incremental Value of Three‐Dimensional Echocardiography over the Two‐Dimensional Technique in the Assessment of Combined Sinus of Valsalva Rupture into the Right Ventricle and Adjacent Perimembranous Ventricular Septal Defect

We describe the incremental value of live/real time three‐dimensional (3D) echocardiography over the 2D technique in the assessment of ruptured right sinus of Valsalva into the right ventricle associated with an adjacent perimembranous ventricular septal defect in an elderly patient.     

Networks in signal transduction: the role of adaptor proteins in platelet activation

In multicellular organisms, the translation of externally applied signals into appropriate cellular responses is mediated by a multitude of complex intracellular signalling cascades. The accurate function of these signalling pathways is based on the sound interaction of proteins of different categories such as transmembrane receptors, protein kinases, protein phosphatases and g-proteins in three-dimensional signalling complexes. During the past 10 years it has became evident that a new class of proteins termed adaptor proteins is indispensable for the assembly of these intracellular signalling scaffolds. The primary function of adaptor proteins is to mediate protein-protein and protein-lipid interactions and thus to integrate receptor-mediated signals at the intracellular level and to couple signalling receptors to cytosolic signalling pathways. In order to perform this task, adapter proteins are equipped with particular protein-protein and/or protein-lipid interaction modules allowing them to communicate with other signalling proteins. While the essential function of adaptor proteins is clearly established in a variety of cell types (e.g. immune cells), the current knowledge about their role in platelet activation is still in the beginning. Numerous adaptor proteins have been shown to be expressed in platelets and many of them seem to be involved in the assembly of signalling complexes after engagement of platelet receptors such as the collagen receptor glycoprotein VI (GPVI), thrombin receptors, integrin receptors and the GP Ib receptor. This review will focus on the functional role of the most extensively studied adaptor proteins during platelet activation.     

The Preoperative Evaluation of Infective Endocarditis via 3-Dimensional Transesophageal Echocardiography

Transesophageal echocardiography continues to have a central role in the diagnosis of infective endocarditis and its sequelae. Recent technological advances offer the option of 3-dimensional imaging in the evaluation of patients with infective endocarditis. We present an illustrative case and review the literature regarding the potential advantages and limitations of 3-dimensional transesophageal echocardiography in the diagnosis of complicated infective endocarditis.A 51-year-old man, an intravenous drug user who had undergone bioprosthetic aortic valve replacement 5 months earlier, presented with prosthetic valve endocarditis. Preoperative transesophageal echocardiography with 3D rendition revealed a large abscess involving the mitral aortic intervalvular fibrosa, together with a mycotic aneurysm that had ruptured into the left atrium, resulting in a left ventricle-to-left atrium fistula. Three-dimensional transesophageal echocardiography enabled superior preoperative anatomic delineation and surgical planning. We conclude that 3-dimensional transesophageal echocardiography can be a useful adjunct to traditional 2-dimensional transesophageal echocardiography as a tool in the diagnosis of infective endocarditis.     

Arterial supply of the distal humerus

Purpose

Distal humeral fractures are rare, but severe injuries, the treatment of which is often accompanied by serious complications and its outcome strongly depends on the quality of surgical therapy. Non-union is a common entity, compromising clinical results and requiring revision surgery. Osteonecrosis is an underestimated etiologic factor in the development of non-union. The present study aims to display the distribution patterns of the arterial vessels at the distal humerus, to correlate the displayed vessels with local nutrient foramina and to disclose an endangerment of these structures by common osteosynthetic implants.

Methods

Eight plastinated fresh frozen upper extremities were digitally analyzed regarding the vascular density of the cancellous bone, by calculating the ratio of area comprised by arterial vessels and the area comprised by cancellous bone on sagittal cuts of the distal humerus. Possible differences in the vascular density of the medial epicondylar region, the lateral epicondylar region and a watershed area between the epicondyles and distal to the supracondylar region were investigated. On the basis of 200 macerated humeri, the distribution pattern of cortical nutrient foramina and their anatomic relation to properly applied common distal humerus plates were documented.

Results

The data show a significantly higher density of vessels per cancellous bone in the epicondylar regions than in the watershed region (p < 0.000, median 0.148 vs. 0.103). The analysis of the nutrient foramina showed distinct distribution patterns with a single foramen over the medial epicondyle (55 specimens, 27.5 %) and an area of several foramina at the posterior part of the lateral epicondyle (200 of the specimens, 100 %). In almost every specimen, the application of the osteosynthetic implants led to an overlay over the investigated nutrient foramina.

Discussion

Osteonecrosis and non-union are severe complications in the surgical treatment of distal humeral fractures. The biology of the bone, especially the blood supply, has to be respected as much as possible during open procedures, to optimize bony healing. This has to be considered when performing periosteal stripping or applying osteosynthetic plates over the postero-lateral and medial epicondyle. The watershed area of the distal humerus has to be considered as being prone to minor arterial blood supply and thereby non-union is possible, if the arterial vessels coming from the epicondyles are destroyed.