Transepithelial paracellular leakiness induced by chronic phorbol ester exposure correlates with polyp-like foci and redistribution of protein kinase C-alpha

Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA) causes a near immediate and total decrease of transepithelial electrical resistance (TER), continuation of exposure for 3 to 4 days results in a tachyphylactic response as TER begins to return to control levels. Recovery of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control level. A reciprocal change in the transepithelial flux of D-mannitol indicates that the TER decrease is indicative of an increase in tight junction permeability. Exposure of cell sheets to TPA for several days also results in the appearance of multilayered polyp- like foci (PLFs) across the otherwise one cell layer thick cell sheets. The pattern of penetration of the electron dense dye, ruthenium red, from the apical surface, across the tight junction and into the lateral intercellular space indicates that the tight junctions of the cell sheet become uniformly leaky after acute exposure to TPA. However, when exposure is continued for several days, only the junctions of cells in the PLFs manifest leakiness. The decrease in TER following acute TPA exposure correlates with the translocation of protein kinase C-alpha (PKC alpha) into a membrane-associated compartment. With exposure of several days, only a trace of PKC alpha is visible by Western immunoblot, and this is in the membrane-associated compartment. Immunofluorescent microscopy indicates that the trace of PKC alpha seen in the Western immunoblots is ascribable distinctly to cells of the PLFs. Monolayer areas between PLFs show no discernible immunofluorescent signal. The data therefore indicate that tight junction barrier function may be restored in certain areas by the down regulation of PKC alpha from the membrane-associated compartment. Failure to down regulate may result in the paracellular leakiness and abnormal cell architecture of the PLFs. Possible implications of this model for in vivo epithelial tumor promotion are discussed.      

Cardiac surgery take-away kit

Background

Trauma to the heart is usually rapidly fatal, but survival can be improved with timely and appropriate surgical management. However, certain injuries require specialist cardiothoracic surgical intervention.

Methods

Three patients with coronary artery lacerations treated by cardiac surgeons at remote hospitals are presented. The recent literature, the current treatment options available and suggestions on techniques to improve survival are reviewed.

Conclusions

Laceration of the coronary arteries is difficult to manage, especially in the absence of specialty equipment. Appropriate protocols should be established to provide this service in order to optimise the management of patients with complicated trauma. A cardiac surgical take‐away kit could facilitate the management of these difficult patients in a setting remote from the cardiac operating room.     

The pelvic digit ��eleventh finger��

Described as asymptomatic and an incidental finding on a plain x-ray film, the “pelvic digit” is a rare congenital anomaly. A 35-year-old man is of a rare symptomatic pelvic digit that warranted surgical excision. Its importance lies in its differentiation from acquired abnormalities due to trauma such as myositis ossificans and avulsion injuries of pelvis. If this entity is kept in mind, unnecessary investigations or interventions can be avoided.     

Spontaneous haematoma of the oesophagus.

Haematoma of the oesophagus is a rare occurrence and is usually in response to trauma, retching or vomiting. We report a case of spontaneous haematoma of the oesophagus that presented with only bruising over the chest. It resolved completely with conservative management. We review the literature, common causes, the differential diagnosis and the management of oesophageal haematoma.