Bibliotheca radiologica

Bone metastases are a common occurrence in carcinoma of the breast, prostate and lung. An understanding of the basic biology of metastatic disease is important for an appreciation of the selective nature of these tumour metastases for bone. Biomechanics of metastatic disease helps explain the proclivity of most metastatic disease for the vertebral column. An understanding of pathophysiology and biochemistry helps in understanding how some tumours produce osteolytic versus osteoblastic or mixed lesions and the relative risks of these deposits. This knowledge leads to an understanding of the difficulties in imaging these lesions and how best to utilize techniques such as SPECT/CT, MRI and PET/CT

The elusive case of human intraepithelial T cells in gut homeostasis and inflammation

The epithelial barrier of the gastrointestinal tract is home to numerous intraepithelial T cells (IETs). IETs are functionally adapted to the mucosal environment and are among the first adaptive immune cells to encounter microbial and dietary antigens. They possess hallmark features of tissue-resident T cells: they are long-lived nonmigratory cells capable of rapidly responding to antigen challenges independent of T cell recruitment from the periphery. Gut-resident T cells have been implicated in the relapsing and remitting course and persisting low-grade inflammation of chronic gastrointestinal diseases, including IBD and coeliac disease. So far, most data IETs have been derived from experimental animal models; however, IETs and the environmental makeup differ between mice and humans. With advances in techniques, the number of human studies has grown exponentially in the past 5 years. Here, we review the literature on the involvement of human IETs in gut homeostasis and inflammation, and how these cells are influenced by the microbiota and dietary antigens. Finally, targeting of IETs in therapeutic interventions is discussed. Broad insight into the function and role of human IETs in gut homeostasis and inflammation is essential to identify future diagnostic, prognostic and therapeutic strategies