Intravascular ultrasound: Virtual histology IVUS, integrated backscatter IVUS, and palpography

The concept of the vulnerable plaque is the focus of much research, although our knowledge of the histology, pathobiology, natural history, and therapy of vulnerable plaque remains incomplete. The evolving intravascular ultrasound technologies of virtual histology, integrated backscatter, and palpography have yielded complementary information to traditional grayscale intravascular ultrasound, and advanced our understanding of vulnerable plaque. Although each of these techniques has enjoyed success in the academic arena, none of these techniques has been sufficiently validated to the extent that would allow it to play a part in clinical decision-making. Their future role, both in regard to risk stratification and identification of vulnerable plaque, will depend upon additional rigorous studies of the natural history and treatment of vulnerable plaque.     

Torsion in patients with superior oblique palsies: dynamic torsion during saccades and changes in Listing’s plane

Background The purpose was to assess intra- and post-saccadic torsion in superior oblique palsy (SOP) patients and the effect of surgery on torsion. Methods Eleven patients with a presumed congenital SOP and five with acquired SOP performed 10° vertical saccades over a range of ±20°. Eye movements were recorded with dual search coils. Dynamic torsion was calculated by subtracting the expected change in torsion during the saccade (based upon static torsion before and after the saccade) from the maximum intrasaccadic torsion. Eight healthy subjects were controls. We also examined the effects of surgery on dynamic torsion and the orientation of Listing’s plane in patients with congenital SOP who were operated on either by weakening of the inferior oblique muscle on the affected eye (n = 5), by recession of the inferior rectus muscle on the normal eye (n = 4) or by both procedures (n = 2). Postoperative recordings were obtained at least 1 month after surgery. Results Patients with congenital and acquired SOP showed an increased dynamic extorsion, primarily during downward saccades. Following a recession of the inferior oblique muscle in congenital SOP patients, half showed significant decreases in extorsion (up to 1.0°) during downward saccades by the affected eye. Following surgery all showed a temporal rotation of Listing’s plane (up to 15° for primary position). Conclusion Patients with a SOP show a characteristic pattern of dynamic torsion during vertical saccades differing from normals. Recession of the inferior oblique muscle leads to rotation of Listing’s plane in all congenital SOP patients and causes large changes in dynamic torsion in a subgroup of them, perhaps reflecting the heterogeneity of congenital SOP. This study was supported by the Deutsche Forschungsgemeinschaft DFG 860/2-1, Bonn Germany, Grant EYO1489, from the National Institute of Health, Bethesda, Maryland, the Abe Pollin scholarship fund, Swiss National Science Foundation Grant 3200B0-105434 and the Betty and David Koetser Foundation for Brain Research, Zurich, Switzerland.     

Hypoxia-selective targeting by the bioreductive prodrug AQ4N in patients with solid tumors: results of a phase I study

PURPOSE: AQ4N is a novel bioreductive prodrug under clinical investigation. Preclinical evidence shows that AQ4N penetrates deeply within tumors and undergoes selective activation to form AQ4, a potent topoisomerase II inhibitor, in hypoxic regions of solid tumors. This proof-of-principle, phase I study evaluated the activation, hypoxic selectivity, and safety of AQ4N in patients with advanced solid tumors. EXPERIMENTAL DESIGN: Thirty-two patients with cancer (8 glioblastoma, 9 bladder, 8 head and neck, 6 breast, and 1 cervix) received a single 200 mg/m(2) dose of AQ4N before elective surgery. AQ4 and AQ4N levels in 95 tissues (tumor, healthy tissue) were assessed by liquid chromatography-tandem mass spectrometry. Tissue sections were also analyzed for AQ4 fluorescence using confocal microscopy, and for expression of the hypoxia-regulated glucose transporter, Glut-1. RESULTS: Activated AQ4 was detected in all tumor samples with highest levels present in glioblastoma (mean 1.2 microg/g) and head and neck (mean 0.65 microg/g) tumors; 22 of 32 patients had tumor AQ4 concentrations > or = 0.2 microg/g, levels previously shown to be active in preclinical studies. In 24 of 30 tumor samples, AQ4 was detected at higher concentrations than in adjacent normal tissue (tumor to normal ratio range 1.1-63.6); distant skin samples contained very low concentrations of AQ4 (mean 0.037 microg/g). Microscopic evaluation of tumor sections revealed that AQ4 colocalized within regions of Glut-1+ hypoxic cells. CONCLUSIONS: AQ4N was activated selectively in hypoxic regions in human solid tumors. Intratumoral concentrations of AQ4 exceeded those required for activity in animal models and support the evaluation of AQ4N as a novel tumor-targeting agent in future clinical studies.     

Quantitative fluorescence imaging analysis for cancer biomarker discovery: application to beta-catenin in archived prostate specimens.

The surprising disparity between the number of protein-encoding genes ( approximately 30,000) in the human genome and the number of proteins ( approximately 300,000) in the human proteome has inspired the development of translational proteomics aimed at protein expression profiling of disease states. Translational proteomics, which offers the promise of early disease detection and individualized therapy, requires new methods for the analysis of clinical specimens. We have developed quantitative fluorescence imaging analysis (QFIA) for accurate, reproducible quantification of proteins in slide-mounted tissues. The method has been validated for the analysis of beta-catenin in archived prostate specimens fixed in formalin. QFIA takes advantage of the linearity of fluorescence antibody signaling for tissue epitope content, a feature validated for beta-catenin in methacarn-fixed prostate specimens analyzed by reverse-phase protein array analysis and QFIA (r = 0.97). QFIA of beta-catenin in formaldehyde-fixed tissues correlated directly with beta-catenin content (r = 0.86). Application of QFIA in a cross-sectional study of biopsies from 42 prostate cancer (PC) cases and 42 matched controls identified beta-catenin as a potential field marker for PC. Receiver operating characteristic plots revealed that beta-catenin expression in the normal-appearing acini of cancerous glands identified 42% (95% confidence intervals, 26-57%) of cancer cases, with 88% (95% confidence intervals, 80-96%) specificity. The marker may contribute to a PC biomarker panel. In conclusion, we report the development and validation of a new method for fluorescence quantification of proteins in archived tissues and its application to archived specimens for an evaluation of beta-catenin expression as a biomarker for PC.     

Inhibition of Jun NH2-terminal kinases suppresses the growth of experimental head and neck squamous cell carcinoma.

PURPOSE: This study was carried out to investigate whether c-Jun NH2-terminal kinases (JNK) are potential targets for treating head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: JNK activity was first evaluated in 20 paired samples of human HNSCC. The antitumor activity of SP600125, a reversible nonselective ATP-competitive inhibitor of JNKs, was then investigated both in an HNSCC xenograft model and in vitro using immunohistochemistry, immunoblotting, enzyme immunoassay, flow cytometry, and a Matrigel assay of capillary tube formation. Complementary studies were carried out using small interfering RNA to JNK1/2. RESULTS: JNK activity was increased in human HNSCC compared with normal-appearing epithelium. Treatment of mice bearing HNSCC xenografts with SP600125 resulted in >60% inhibition of tumor growth relative to vehicle-treated animals. Inhibition of tumor growth was associated with significant reductions in both cell proliferation and microvessel density. SP600125 inhibited tumor cell proliferation by causing delays in both the S and G2-M phases of the cell cycle. Inhibition of angiogenesis seemed to reflect effects on both tumor and endothelial cells. The JNK inhibitor suppressed the production of vascular endothelial growth factor and interleukin-8 by tumor cells and also inhibited endothelial cell proliferation and capillary tube formation. Reduced amounts and phosphorylation of epidermal growth factor receptor were found in tumor cells after treatment with SP600125. Small interfering RNA-mediated suppression of JNK1/2 led to reduced tumor cell proliferation and decreased levels of epidermal growth factor receptor, vascular endothelial growth factor, and interleukin-8. CONCLUSIONS: JNK activity is commonly increased in HNSCC. Our preclinical results provide a rationale for evaluating JNK inhibition as an approach to treating HNSCC.