Comparison of hamate versus second or third toe osteochondral graft using magnetic resonance imaging for reconstruction of proximal interphalangeal fracture-dislocations.

Hemi-hamate arthroplasty is a method used to reconstruct complex fracture-dislocations of the proximal interphalangeal joint of the fingers. Other graft sites, including the toe second and third phalanges, have been proposed as alternatives to hemi-hamate arthroplasty due to variable clinical outcomes and anatomy. Through a prospective magnetic resonance imaging (MRI)-based study in asymptomatic individuals, we aimed to characterize the anatomy of the proximal interphalangeal joint and compare this with the hamate, second and third toes to determine the closest anatomical match using pre-determined measurements. Our results show that the second and third toes have greater anatomical similarity to the proximal interphalangeal joint of the fingers compared to the hamate. High-resolution MRI is a reliable method of characterizing the anatomy of these structures and could be a useful clinical tool in determining reconstructive options in the management of this challenging injury.Level of evidence: II.

Acute Adult-Onset Kawasaki Disease Complicated by Coronary Artery Aneurysms, Thrombosis, and ST-Segment Elevation Myocardial Infarction.

A 21-year-old man who had an initial misdiagnosis of chest wall cellulitis and sepsis presented to the emergency department with chest pain. Electrocardiogram demonstrated ST-segment elevation in the inferior leads. Cardiac catheterization identified diffuse aneurysmal dilation and thrombosis of the distal right coronary artery. Clinical signs were consistent with acute Kawasaki disease. (Level of Difficulty: Intermediate.).

Gastrocolonic fistula: a rare complication of upper gastrointestinal surgery.

A gastrocolonic fistula is a rare surgical presentation, typically in the setting of gastric or colonic malignancy. This report presents the first reported Australian case of a gastrocolonic fistula following upper gastrointestinal surgery. A middle-aged woman presented to emergency with a short history of severe abdominal pain, faeculent vomiting, profuse diarrhoea and weight loss. This was in the setting of a previous pylorus-preserving pancreaticoduodenectomy complicated by marginal ulceration, for which a distal gastrectomy and Roux-en-Y reconstruction was required. The rarity of gastrocolonic fistulae and non-specific presentation with diarrhoea, vomiting and weight loss can make the diagnosis challenging. The mainstay of management is surgical resection in both benign and malignant disease.

Transcriptional regulatory control of mammalian nephron progenitors revealed by multi-factor cistromic analysis and genetic studies.

Nephron progenitor number determines nephron endowment; a reduced nephron count is linked to the onset of kidney disease. Several transcriptional regulators including Six2, Wt1, Osr1, Sall1, Eya1, Pax2, and Hox11 paralogues are required for specification and/or maintenance of nephron progenitors. However, little is known about the regulatory intersection of these players. Here, we have mapped nephron progenitor-specific transcriptional networks of Six2, Hoxd11, Osr1, and Wt1. We identified 373 multi-factor associated 'regulatory hotspots' around genes closely associated with progenitor programs. To examine their functional significance, we deleted 'hotspot' enhancer elements for Six2 and Wnt4. Removal of the distal enhancer for Six2 leads to a ~40% reduction in Six2 expression. When combined with a Six2 null allele, progeny display a premature depletion of nephron progenitors. Loss of the Wnt4 enhancer led to a significant reduction of Wnt4 expression in renal vesicles and a mildly hypoplastic kidney, a phenotype also enhanced in combination with a Wnt4 null mutation. To explore the regulatory landscape that supports proper target gene expression, we performed CTCF ChIP-seq to identify insulator-boundary regions. One such putative boundary lies between the Six2 and Six3 loci. Evidence for the functional significance of this boundary was obtained by deep sequencing of the radiation-induced Brachyrrhine (Br) mutant allele. We identified an inversion of the Six2/Six3 locus around the CTCF-bound boundary, removing Six2 from its distal enhancer regulation, but placed next to Six3 enhancer elements which support ectopic Six2 expression in the lens where Six3 is normally expressed. Six3 is now predicted to fall under control of the Six2 distal enhancer. Consistent with this view, we observed ectopic Six3 in nephron progenitors. 4C-seq supports the model for Six2 distal enhancer interactions in wild-type and Br/+ mouse kidneys. Together, these data expand our view of the regulatory genome and regulatory landscape underpinning mammalian nephrogenesis.

Presentation of Anatomical Variations Using the Aurasma Mobile App.

Knowledge of anatomical variations is critical to avoid clinical complications and it enables an understanding of morphogenetic mechanisms. Depictions are comprised of photographs or illustrations often limiting appreciation of three-dimensional (3D) spatial relationships. The purpose of this study is to describe an approach for presenting anatomical variations utilizing video clips emphasizing 3D anatomical relationships delivered on personal electronic devices. An aberrant right subclavian artery (ARSA) was an incidental finding in a routine dissection of an 89-year-old man cadaver during a medical student instructional laboratory. The specimen was photographed and physical measurements were recorded. Three-dimensional models were lofted and rendered with Maya software and converted as Quicktime animations. Photographs of the first frame of the animations were recorded and registered with Aurasma Mobile App software (www.aurasma.com). Resulting animations were viewed on mobile devices. The ARSA model can be manipulated on the mobile device enabling the student to view and appreciate spatial relationships. Model elements can be de-constructed to provide even greater spatial resolution of anatomical relationships. Animations provide a useful approach for visualizing anatomical variations. Future work will be directed at creating a library of variants and underlying mechanism of formation for presentation through the Aurasma application.