Practical approach to MRI of female pelvic masses.

OBJECTIVE: Female pelvic masses have a broad differential diagnosis, including benign and malignant neoplasms and nonneoplastic entities. CONCLUSION: By using a systematic approach to the evaluation of a complex pelvic mass, including incorporating the clinical and surgical history, and by using multiparametric MRI to identify the anatomic origin, morphologic features, and tissue composition of a mass, a short meaningful differential diagnosis or definitive diagnosis can often be established.

Ischemia/reperfusion-induced renal failure in rats as a model for evaluating cell therapies.

Chronic renal failure is a devastating disease that leads to a multitude of complications. Cell therapy has emerged as a potential treatment modality for renal failure. However, efficacy testing on systemic renal function has been challenging due to the limited availability of reliable models that are fully characterized. In this study, we investigated the possibility of using renal ischemia/reperfusion (I/R) injury as a viable model for testing cell therapies. We examined functional and pathological changes in rat kidneys that were exposed to different ischemia times. Male Lewis rats were divided into five groups. Renal failure was induced by clamping both renal pedicles for combinations of 60, 75, and 90 min, followed by reperfusion. Age-matched healthy rats served as controls. Blood was collected at regular intervals for serum chemistry, and kidneys were harvested at the same intervals for histomorphological assessment. Serum creatinine levels of the animals with I/R injury increased significantly after 3 days and returned to normal levels at 4 weeks. Histologically, kidney tissue showed progressive glomerular and tubular deterioration with varying degrees of fibrosis. Animals exposed to 75- and 90-min ischemia combination times consistently generated more severe injury than the 60-min ischemia period. However, these groups resulted in a high mortality rate. A model in which one kidney is exposed to a shorter ischemia time (60 or 90 min) resulted in sustained renal damage with a lower mortality rate. This study shows that kidneys exposed to I/R result in renal tissue damage as well as decreased renal function. This model can be used to study both the short-term and longer-term effects of kidney disease by varying the length of the ischemic time. In particular, the use of longer ischemic times (75 and 90 min) could be used to study new therapies for acute renal disease, whereas shorter ischemic times (60 min) could be used to study therapies for chronic renal insufficiency.

Controlled regulation of erythropoietin by primary cultured renal cells for renal failure induced anemia.

PURPOSE: Renal failure induced anemia develops as a result of inadequate production of erythropoietin, which is the primary regulator of red blood cell production. We previously noted that culture expanded primary renal cells stably express erythropoietin and suggested that these cells may be used as a potential treatment for renal failure induced anemia. We investigated whether these cells are able to regulate erythropoietin expression in a controlled manner under different oxygen and environmental conditions. MATERIALS AND METHODS: Primary rat renal cells were exposed to different hypoxic (0.1% to 1% O(2)) and normoxic environments. Erythropoietin expression was assessed using reverse transcriptase-polymerase chain reaction. Erythropoietin production was measured in culture medium using Meso Scale Discovery® assays. Results were plotted to compare different levels of production to the control. RESULTS: Cultured renal cells expressed high levels of erythropoietin under hypoxia for up to 24 hours with a gradual decrease thereafter. However, erythropoietin expression was decreased when cells were switched from a hypoxic to a normoxic environment within the initial 24 hours. This indicated that cultured renal cells have the capacity to sense environmental oxygen tension and regulate erythropoietin expression accordingly. In addition, erythropoietin release in medium followed a pattern similar to that of gene expression under normoxic and hypoxic conditions. CONCLUSIONS: These findings indicate that primary renal cells have the ability to regulate erythropoietin gene expression and release through environment dependent mechanisms. This also suggests that with further study the possibility exists of developing these cells as a potential method to treat renal failure induced anemia.