2D-shear wave elastography in the evaluation of suspicious superficial inguinal lymph nodes: Reproducibility and region of interest selection.

PURPOSE: To assess the ability of 2D-Shear wave elastography (2D-SWE) to evaluate its reproducibility, to define the optimal orientation and size of the region of interest (ROI), and to differentiate benign from malignant inguinal lymph nodes (LNs). METHOD: Thirty-two suspicious inguinal LNs from 21 patients were evaluated with 2D-SWE. SWE measurements were obtained in two orthogonal planes. To investigate reproducibility, sensitivity and specificity, circular ROIs with a diameter of 1 mm, 2 mm, 3 mm and 5 mm were placed on the cortex of the LNs. Additionally, one freehand ROI was drawn covering majority of the LN. Two observers performed five sets of SWE measurements for each ROI size. All LNs underwent core needle biopsy or were surgically removed. RESULTS: The 3 mm ROI for Mean-E in axial plane showed high interrater agreement [intraclass correlation coefficient (ICC) 0.899] with the cut-off value of 7.31 kPa resulting in 88.9% sensitivity and 60.9% specificity for differentiating malignant from benign LNs. In benign LNs, mean elasticity of the ROI was lower (7.68 ± 3.82 kPa; range, 3.41-15.40 kPa) compared to the malignant LNs (15.81 ± 10.61 kPa; range, 3.86-36.45 kPa). CONCLUSIONS: The most reproducible way to measure stiffness in inguinal LNs is a 3 mm circular ROI centered on the cortex of the LN in axial plane. Elasticity values were higher in the malignant LNs reflecting the stiffer nature of the metastatic LNs. 2D-SWE offers a noninvasive ultrasonographic tool to assess superficial inguinal lymph nodes with high reproducibility.

In vivo implantation of 2,2'-bis(oxazoline)-linked poly-epsilon-caprolactone: proof for enzyme sensitive surface erosion and biocompatibility.

Previously, we have demonstrated that 2,2-bis(2-oxazoline) linked poly-epsilon-caprolactone (PCL-O) is degraded in vitro enzymatically by surface erosion which could enable the novel use of this material for drug delivery and other biomedical applications. In this study, degradation, erosion (weight loss) and toxicity of PCL-O poly(ester-amide)s were evaluated in vivo. PCL and three PCL-O polymers with different PCL block lengths (M(n): 1500, 3900, 7500 g/mol) were melt-pressed in the form of discs and implanted subcutaneously in Wistar rats (dose approximately 340 mg/kg) for 1, 4 and 12 weeks. With implantation for 12 weeks, up to 16.5% weight loss of polymer discs was measured for the most extensively linked PCL-O polymer (block length 1500 g/mol) whereas practically no weight loss was observed with the other polymers. NMR, DSC and SEC studies as well as SEM micrographs before and after implantation and in vitro hydrolysis studies indicate that enzyme based surface erosion of PCL-O polymers occurred in vivo. The in vivo evaluation based on results from hematology, clinical chemistry and histology of the implantation area and main organs (i.e. heart, lung, liver, kidney, spleen and brain) demonstrated that PCL-O polymers are biocompatible and safe, enzyme sensitive biomaterials.

Three-step tumor targeting of paclitaxel using biotinylated PLA-PEG nanoparticles and avidin-biotin technology: Formulation development and in vitro anticancer activity.

Despite recent advances in cancer therapy, many malignant tumors still lack effective treatment and the prognosis is very poor. Paclitaxel is a potential anticancer drug, but its use is limited by the facts that paclitaxel is a P-gp substrate and its aqueous solubility is poor. In this study, three-step tumor targeting of paclitaxel using biotinylated PLA-PEG nanoparticles and avidin-biotin technology was evaluated in vitro as a way of enhancing delivery of paclitaxel. Paclitaxel was incorporated both in biotinylated (BP) and non-biotinylated (LP) PEG-PLA nanoparticles by the interfacial deposition method. Small (mean size approximately 110 nm), spherical and slightly negatively charged (-10 mV) BP and LP nanoparticles achieving over 90% paclitaxel incorporation were obtained. The successful biotinylation of nanoparticles was confirmed in a novel streptavidin assay. BP nanoparticles were targeted in vitro to brain tumor (glioma) cells (BT4C) by three-step avidin-biotin technology using transferrin as the targeting ligand. The three-step targeting procedure increased the anti-tumoral activity of paclitaxel when compared to the commercial paclitaxel formulation Taxol and non-targeted BP and LP nanoparticles. These results indicate that the efficacy of paclitaxel against tumor cells can be increased by this three-step targeting method.

High-performance liquid chromatography/electrospray ionization tandem mass spectrometry for characterization of enzymatic degradation of 2,2'-bis(2-oxazoline)-linked poly-epsilon-caprolactone.

This paper describes a straightforward and rapid on-line characterization using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS(n)) of the enzymatic degradation products of 2,2'-bis(2-oxazoline)-linked poly-epsilon-caprolactone (PCL-O). These new PCL-O polymers are expected to be used in a variety of pharmaceutical and biomedical applications since they are degraded enzymatically by surface erosion. PCL-O was polymerized in a three-step reaction and characterized by (1)H-NMR and size-exclusion chromatography (SEC). Solvent cast polymer films were exposed to enzymatic degradation in phosphate buffer (pH 7.5, 1% pancreatin). The enzymatic degradation of the polymer produced a wide variety of water-soluble oligomers which were separated and identified by HPLC/ESI-MS(n). Optimization of the gradient HPLC method resulted in effective separation of the oligomers. Furthermore, specific structures of the oligomers were clearly identified by tandem mass spectrometry. According to these results, ester bonds seem to be most sensitive to enzymatic degradation and, correspondingly, pancreatic lipase seems to be mainly responsible for the enzymatic erosion of the PCL-O films. This novel mass spectrometric method provides important knowledge about the enzymatic degradation process and structure of the polymer which is difficult to ascertain by other conventional methods.

Effects of block length on the enzymatic degradation and erosion of oxazoline linked poly-epsilon-caprolactone.

The aim of the study was to develop enzyme sensitive polymers for pharmaceutical applications. Thus, 2,2'-bis(2-oxazoline)-linked poly-epsilon-caprolactone (PCL-O) polymers were synthesized by using epsilon-caprolactone precursors with different molecular weights (M(n): 1500, 3900, 7500 and 12,000g/mol), and the effects of PCL block length on enzymatic degradation and erosion (weight loss) of PCL-O films were studied. Solvent cast PCL and PCL-O films were incubated (22 days) in the presence of pancreatin (1%, pH 7.5), with and without enzyme inhibitors. In the absence of enzyme inhibitors, surface erosion of the PCL-O films occurred during incubation, and the erosion of the PCL-O films increased in parallel with a decrease in the PCL block length. The presence of the lipase inhibitors, paraoxon-ethyl and tetrahydrolipstatin delayed the weight loss of the PCL-O films. These results indicate that lipase was mainly responsible for the enzymatic erosion of the PCL-O films. In comparison, practically no weight loss of the PCL or the PCL-O films was observed in phosphate buffer (pH 7.4) (28 days incubation). The results demonstrate that the studied epsilon-caprolactone based poly(ester-amide)s are enzyme sensitive polymers whose erosion rate can be controlled by the PCL block length.