Sonographic evaluation of prostatic artery embolization: Far beyond size measurements

Prostatic artery embolization (PAE) has gained acceptance as a minimally invasive, safe and effective treatment of symptomatic benign prostatic hyperplasia. Radiologic imaging is an indispensable part of post-interventional evaluation of PAE and serves both clinical and investigational purposes. In this context, ultrasonography (US) has a central and multifaceted role. Gray-scale US is routinely utilized for measurement of significant outcome parameters (prostatic volume, intra-vesical prostatic protrusion and post-void residual volume) before and after PAE. Improvement of these parameters may become more obvious one-month post-PAE, or later. Contrast-enhanced US (CEUS) with intravenous administration of a second-generation echo-enhancer can demonstrate prostatic infarcts (as enhancement defects) immediately post-PAE and monitor their resolution over time. The volume of prostatic infarcts can also be measured and compared to prostatic volume. Prostatic infarction is a definite sign of the local efficacy of PAE and a predictor of prostate shrinkage and (at least in some patients) of clinical success. CEUS can also be performed intraoperatively in the angio-suite, for on-site evaluation of the ischemic effect; a variation of this technique, with intraarterial (instead of intravenous) administration of diluted echo enhancer, can also be applied intraoperatively, to map the embolized territory and to prevent non-target embolization. Initial experience with US-elastographic techniques (shear-wave and strain elastography) has shown that they can detect and quantify the improvement of tissue elasticity post-PAE, thus providing new insights into the therapeutic mechanisms of this treatment. With utilization of high-end equipment, experience and standardized imaging protocols, US could be the primary modality for imaging evaluation of PAE.

Transarterial Chemoembolization of HCC with Radiopaque Microspheres: Evaluation with Computed Tomography and the Complementary Role of Contrast-Enhanced Ultrasonography

PURPOSE

To assess the diagnostic performance of computed tomography (CT), and of the combination of CT with contrast-enhanced ultrasonography (CT + CEUS), for the early evaluation of local response of hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE) with radiopaque drug-eluting microspheres (RO-DEMs).

MATERIALS AND METHODS

30 HCC patients (55 target tumors) were treated with TACE with RO-DEMs (diameter: 70-150 μm) preloaded with 75 mg doxorubicin/2 ml of microspheres. Unenhanced and contrast-enhanced CT, followed by CEUS, were performed 1-3 days post-RO-DEMs-TACE. Contrast-enhanced magnetic resonance (MR) performed 1 month later served as the reference standard. Local tumor response was evaluated with modified Response Evaluation Criteria in Solid Tumors (mRECIST).

RESULTS

MR diagnosed 9 tumors with complete response and 46 with residual disease. Compared to MR, CT had 9 false negative and 1 false positive diagnosis for residual tumor. Potential causes for these misdiagnoses were the hyperdensities and associated artifacts (caused by the accumulation of RO-DEMs in the target tumors) and the small size of residual tumor. CT + CEUS had 3 false negative and no false positive diagnosis for residual tumor. The sensitivity, specificity and diagnostic accuracy of CT for detection of residual tumor were, respectively: 80.4%, 88.9% and 81.8%, and for CT + CEUS: 93.5%, 100% and 94.5%, respectively. Agreement (kappa coefficient) in application of mRECIST between MR and CT was lower than between MR and CT + CEUS (0.508 vs. 0.757).

CONCLUSION

CT evaluation of TACE with RO-DEMs is associated with limitations which can be partially overcome by combining CT with CEUS.

Adenovirus E1A requires c-Ras for full neoplastic transformation or suppression of differentiation of murine preadipocytes

We recently demonstrated that the Adenovirus-5 E1A gene products (E1A), known E2F activators, can block the differentiation of murine preadipocytes and that differentiation suppression occurs at lower levels than required for full neoplastic transformation. Progressively higher levels were accompanied by apoptosis induction. To examine the role of the cellular Ras protooncogene product (Ras) in E1A function, E1A was expressed in C3H10T(1/2) (10T(1/2))-derived preadipocytes rendered deficient in Ras activity by transfection with inducible or constitutive antisense ras gene constructs (Ras-knockdowns). The results showed that, although even low amounts of E1A could block the differentiation of 10T(1/2) preadipocytes with normal Ras levels, even the highest E1A levels were unable to block the differentiation or induce transformation of Ras-knockdown preadipocytes. Ras downregulation did not affect E2F activation by E1A. Interestingly, our results further demonstrated a dramatic reduction in the levels of the E1A protein itself as differentiation progressed, with a concomitant reduction in E1A's ability to induce apoptosis as a result. These findings suggest for the first time that Ras, although cytoplasmic, is an integral component of the pathway whereby E1A, an oncoprotein believed to have primarily nuclear targets, suppresses differentiation or induces neoplastic conversion of murine preadipocytes.

Rhodium and its compounds as potential agents in cancer treatment

The antitumor activity of the inorganic complex cis-diammine-dichloroplatinum(II) (cisplatin) led to the development of other types of non-organic cytostatic drugs. Numerous platinum other platinum and non-platinum metal compounds were shown to be effective against animal model tumors as well as tumors in man. However, the introduction of novel transition metal agents in clinical treatment is exceptionally slow. So far, Ru(II) and Ru(III) complexes have shown very promising properties while the Ru(III) compound, [ImH][trans-Cl4(Me2SO)(Im)Ru(III)] (Im=imidazole, NAMI-A), is the first ruthenium compound that successfully entered phase I clinical trials. Rhodium belongs to the same group as platinum and ruthenium. However, rhodium compounds, analogues to the corresponding platinum and ruthenium compounds that possess significant antitumor properties, were found to be less effective as anticancer agents mainly due to their toxic effects. Dimeric mu-Acetato dimers of Rh(II) as well as monomeric square planar Rh(I) and octahedral Rh(III) complexes have shown interesting antitumor properties.

Interaction of cis- and trans-RuCl2(DMSO)4 with the nucleotides GpA, d(GpA), ApG, d(ApG) and d(CCTGGTCC): high-field NMR characterization of the reaction products

Both cis- and trans-RuCl2(DMSO)4 (cis-Ru and trans-Ru) react with ApG, GpA, d(ApG) and d(GpA) to yield products with bifunctional metal coordination of the bases. For each dinucleotide one major product and several minor species are formed. This is in contrast to previous results on analogous reactions between trans-Ru and d(GpG) where a substantial amount of an intermediate species was found. The rates of reaction between dinucleotides and cis-Ru are approximately 20-fold slower than for trans-Ru. The compounds formed with the two isomers exhibit identical proton NMR spectra, suggesting the same coordination mode for ruthenium in the final product. The two purine bases are coordinated to ruthenium through N7 in a head-to-head conformation with the glycosidic angles being in the anti range. Coupling constants indicate a relatively pure 3'-endo conformation for the 5'-sugar and mainly 2'-endo for the 3'-sugar. The similar bifunctional binding mode of cis- and trans-Ru(II) with dinucleotides as evident from the NMR spectra are in contrast to the different mode of interaction suggested earlier for cis- and trans-Ru complexes with DNA. trans-Ru interacts with the deoxyoctanucleotide d(CCTGGTCC), giving two main products during the first 2 h of incubation time. Four H8 guanine resonances are shifted downfield, characteristic of N7 metal coordination. The products are not analyzed in detail, but it is suggested that the structures may be described as two chiral G(N7/N7) chelates.