A renal angiomyolipoma with a challenging presentation: a case report

INTRODUCTION

Renal angiomyolipoma is considered a benign mesenchymal tumor composed of fat, smooth muscle, and blood vessels. It represents 1-3% of solid renal tumors. Despite this tumor's benignity, it can be aggressive with a locoregional extension.

CASE REPORT

A 41-year-old north African caucasian woman consulted with chief complaints of right lower back pain with no hematuria and no urinal sign. Thoracic-abdominopelvic contrast-enhanced computed tomography showed a right inferior polar heterogeneous renal mass complicated with venous thrombus ascending to the right atrium level. The patient underwent radical nephrectomy under extracorporeal circulation and direct supervision of the fatty thrombus at the right atrium level. The postoperative period was uneventful. The final histologic examination was concordant with renal angiomyolipoma.

CONCLUSION

Renal angiomyolipoma is the most common benign kidney tumor. Despite its benignity, it can be associated with lethal complications such as hemorrhage, and it can also show signs of local extension mimicking malignant tumors. The cornerstone of the treatment remains surgery.

A highly versatile adaptor protein for the tethering of growth factors to gelatin-based biomaterials

In the field of tissue engineering, the tethering of growth factors to tissue scaffolds in an oriented manner can enhance their activity and increase their half-life. We chose to investigate the capture of the basic Fibroblast Growth Factor (bFGF) and the Epidermal Growth Factor (EGF) on a gelatin layer, as a model for the functionalization of collagen-based biomaterials. Our strategy relies on the use of two high affinity interactions, that is, the one between two distinct coil peptides as well as the one occurring between a collagen-binding domain (CBD) and gelatin. We expressed a chimeric protein to be used as an adaptor that comprises one of the coil peptides and a CBD derived from the human fibronectin. We proved that it has the ability to bind simultaneously to a gelatin substrate and to form a heterodimeric coiled-coil domain with recombinant growth factors being tagged with the complementary coil peptide. The tethering of the growth factors was characterized by ELISA and surface plasmon resonance-based biosensing. The bioactivity of the immobilized bFGF and EGF was evaluated by a human umbilical vein endothelial cell proliferation assay and a vascular smooth muscle cell survival assay. We found that the tethering of EGF preserved its mitogenic and anti-apoptotic activity. In the case of bFGF, when captured via our adaptor protein, changes in its natural mode of interaction with gelatin were observed.

STATEMENT OF SIGNIFICANCE

In an effort to functionalize collagen/gelatin-based biomaterials with growth factors, we have designed an adaptor protein corresponding to a collagen-binding domain fused to a coil peptide. In our strategy, this adaptor protein captures growth factors being tagged with the partner coil peptide in a specific, stable and oriented manner. We have found that the tethering of the Epidermal Growth Factor preserved its mitogenic and anti-apoptotic activity. In the case of the basic Fibroblast Growth Factor, the captured growth factor remained bioactive although its tethering via this adaptor protein modified its natural mode of interaction with gelatin. Altogether this strategy is easily adaptable to the simultaneous tethering of various growth factors.

[Analysis of the appropriateness of hospitalizations in Monastir, Tunisia]

We aimed to measure the extent of inappropriate hospital admissions and to identify factors associated with inappropriate hospital use. A descriptive study was carried out on a randomized sample of 411 hospitalizations in 3 regional hospitals. The appropriateness of admissions was assessed using the Appropriateness Evaluation Protocol (AEP). We found 21% (95% CI: 17%-25%) of the admissions were avoidable according to the AEP. Inappropriate admissions were associated with the hospital (P = 0.005), patient age (P = 0.003), length of stay and diagnosis (P < 0.001). The most frequent reasons for appropriate admissions were parenteral therapy, an acute or progressive sensory motor circulatory or respiratory condition sufficient to incapacitate the patient and severe electrolyte or blood gas abnormality. Our study highlights the need to improve hospital management and to develop alternatives to hospitalization.

Diabetes and hospital morbidity in the Monastir governorship (Tunisia)

Diabetes is a public health problem worldwide. In Tunisia, the rate of prevalence is 3.8% in urban areas and 1.3% in rural areas, whereas the socioeconomic impact of the disease has rarely been investigated. This study conducted in the Monastir health district evaluated the burden of hospital care for diabetes. All admissions for diabetes (973) recorded in the regional morbidity register during 1993 for all public hospitals in the region were taken into consideration. Admission for diabetes represented 5.9% of total admissions and was the first cause of hospitalisation. The university hospital centre received 40% of these patients. The annual hospital rate of diabetes is estimated to be 2.7%, but varies according to the district considered and the age of patients (1.1% for those under 50 years of age and 12.8% for those over 65). The number of days of hospitalization related to diabetes was 10,069, i.e. 7.6% of the total for the district. The mean cost of a single hospitalization is about 251 Tunisian dinars (US$251). Diabetes treatment could be improved and the cost lowered by providing appropriate ambulatory care and health education to reduce hospital admissions.