Purpose:To determine if oxidative and nitrative stress and/or apoptosis contribute to increased coagulation when combining radiofrequency (RF) ablation with liposomal doxorubicin.
Materials and Methods:Animal care committee approval was obtained. R3230 mammary adenocarcinomas in Fischer rats were treated with either RF ablation ( n = 43), 1 mg of intravenously injected liposomal doxorubicin ( n = 26), or combined therapy ( n = 30) and were compared with control subjects ( n = 11). A subset of animals receiving combination therapy ( n = 24) were treated in the presence or absence of N -acetylcysteine (NAC) administered 24 hours and 1 hour before RF ablation. Tumors were analyzed 2 minutes to 72 hours after treatment to determine the temporal range of response by using immunohistochemical staining of the apoptosis marker cleaved caspase-3, phosphorylated g H2AX , and
Results:By 4 hours after RF ablation alone, a 0.48-mm 6 0.13 (standard deviation ) peripheral band with 57.0% 6 7.3 cleaved caspase-3 positive cells was noted at the ablation margin, whereas a 0.73-mm 6 0.18 band with 77.7% 6 6.3 positivity was seen for combination therapy ( P , .03 for both comparisons). Combination therapy caused increased and earlier staining for 4-HNE-modifi ed proteins, 8-OHdG, NT, and g H2AX with colocalization to cleaved caspase-3 staining. A rim of increased HSP70 was identifi ed peripheral to the area of cleaved caspase-3. Parameters of oxidative and nitrative stress were signifi cantly inhibited by NAC 1 hour following RF ablation, resulting in decreased cleaved caspase-3 positivity (0.28-mm 6 0.09 band of 25.9% 6 7.4 positivity vs 0.59-mm 6 0.11 band of 62.9% 6 6.0 positivity, P , .001 for both comparisons).
Conclusion:Combining RF ablation with liposomal doxorubicin increases cell injury and apoptosis in the zone of increased coagulation by using a mechanism that involves oxidative and nitrative stress that leads to accelerated apoptosis.q RSNA, 2010
Neph1-deficient mice develop nephrotic syndrome at birth, indicating the importance of this protein in the development of a normal glomerular filtration barrier. While the precise subcellular localization of Neph1 remains unknown, its relationship with other components of the glomerular filtration barrier is of great interest in this field. In this paper, we localize the expression of Neph1 to the glomerular slit diaphragm by immunogold electron microscopy in rodents and describe its direct interaction with two other components of the slit diaphragm, nephrin and ZO-1. Both native and recombinant Neph1 associate with each other as dimers and multimers and interact with nephrin via their extracellular segments. Disruption of the Neph1-nephrin interaction in vivo by injecting combinations of individual subnephritogenic doses of anti-Neph1 and anti-nephrin results in complement- and leukocyte-independent proteinuria with preserved foot processes. This disruption modestly reduces Neph1 and nephrin protein expression in podocytes and dramatically reduces ZO-1 protein expression via the interaction of ZO-1 PDZ domains with the cytoplasmic tail of Neph1, independent of changes in mRNA expression of all three genes. The interaction between nephrin and Neph1 is specific and not shared by either protein with P-cadherin, another integral slit diaphragm protein. The interaction between nephrin and Neph1 therefore appears to be an important determinant of glomerular permeability
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