Optimization and validation of a multiplexed luminex assay to quantify antibodies to neutralizing epitopes on human papillomaviruses 6, 11, 16, and 18

A human papillomavirus (HPV) multiplexed competitive Luminex immunoassay first described by Opalka et al. (D. Opalka, C. E. Lachman, S. A. MacMullen, K. U. Jansen, J. F. Smith, N. Chirmule, and M. T. Esser, Clin. Diagn. Lab. Immunol. 10:108--15, 2003) was optimized and validated for use in epidemiology studies and vaccine clinical trials. Optimization increased both the analytical sensitivity and the clinical specificity of the assay to more effectively discriminate the low-titer antibody response of HPV-infected persons from noninfected individuals. The characteristics of the assay that were optimized included monoclonal antibody (MAb) specificity, scaling up the conjugation of virus-like particles (VLPs) to microspheres, VLP concentration, MAb concentration, sample matrix, sample dilution, incubation time, heat inactivation of sample sera, and detergent effects on assay buffer. The assay was automated by use of a TECAN Genesis Workstation, thus improving assay throughput, reproducibility, and operator safety. Following optimization, the assay was validated using several distinct serum panels from individuals determined to be at low and high risk for HPV infection. The validated assay was then used to determine the clinical serostatus cutoff. This high-throughput assay has proven useful for performing epidemiology studies and evaluating the efficacy of prophylactic HPV vaccines.     

The VEGF receptor tyrosine kinase inhibitor,ZD6474, inhibits angiogenesis and affects microvascular architecture within an orthotopically implanted renal cell carcinoma

The proangiogenic vascular endothelial growth factor-A (VEGF) is essential for the development of new tumor vessels. ZD6474 is a novel inhibitor of VEGF receptor-2 (VEGFR-2) tyrosine kinase activity, which also has additional activity against epidermal growth factor (EGF) receptor tyrosine kinase. The antitumor activity of different schedules of ZD6474 in a clinically relevant, metastasizing, murine renal cell carcinoma (RENCA) model was evaluated in this study. RENCA cells were inoculated into the left kidney of 24 mice (day 0). Daily ZD6474 (50 mg/kg p.o.) treatment was initiated 1 day or 10 days after tumor cell inoculation and continued until day 21. Following treatment, kidney weight and volume were assessed and blood vessel density determined by CD31 staining. Visible metastases in the lungs, spleen, and lymph nodes were quantified using a dissection microscope. In an additional study, animals were treated according to the same regimen and quantitative three-dimensional microvascular corrosion casting was performed to enable detailed assessment of the tumor vascular architecture. Therapy initiated on day 1 or day 10 resulted in a 79% and 59% reduction in primary tumor volume, a 79% and 60% reduction in the number of lung metastases, and a 58% and 59% reduction in vessel density of primary tumors compared with the control group, respectively. Corrosion casting proved a 5.4- and 3.2-fold lower vascular volume compared with untreated tumors, observations that paralleled with significant architectural alterations. In this RENCA model, ZD6474 was a highly active inhibitor of tumor angiogenesis, primary tumor growth and tumor metastasis.Both authors have contributed equally to this work.     

Liposomal pegylated doxorubicin versus low-dose recombinant interferon Alfa-2a in the treatment of advanced classic Kaposi's sarcoma; retrospective analysis of three German centers

BACKGROUND: Classic Kaposi's sarcoma (KS) is a rare neoplasm, predominantly occurring in older subjects of Eastern Europe or Mediterranean descent. While single lesions may be treated by simple excision, laser therapy, cryotherapy, or intralesional therapy, advanced or disseminated disease requires systemic treatment. Several studies reported the effectiveness of pegylated liposomal doxorubicin (PLD) and low-dose recombinant interferon alfa-2a (IFNalpha) in the treatment of AIDS-associated KS. OBJECTIVE: The aim of this retrospective analysis of three German centers was to compare the effectiveness and tolerability of PLD with IFNalpha in patients with advanced classic KS. METHODS: Retrospective analysis of 18 Caucasian patients who had been treated for histologically proven classic KS, with either with PLD or IFNalpha was performed. Twelve patients received 20 mg/m2 of PLD monthly, and the number of cycles was adapted to the clinical response. Dose reduction or increased cycle length was conducted if toxicity intervened. In 6 patients, 3 million U of IFNalpha was injected subcutaneously 3 times a week. IFNalpha -therapy was adapted according to the clinical response. RESULTS: In the 12 KS patients treated with PLD, complete response (CR) was achieved in 8 (67 percent), major response (MR) in 3 (25 percent), and minor response (mR) in 1 (8 percent). Stable disease (SD) or progression of disease (PD) was not observed. An initial response was noted after 4-16 weeks of treatment (mean 8.6 weeks), the mean cumulative dose of PLD was 571.5 mg/m2 (range, 40 to 1496 mg/m2), and the mean follow-up was 13 months. Neutropenia (33 percent) related to PLD was the most common adverse event (4/12). Vomiting occurred in 3 (25 percent) patients; none of these were severe. Six patients were treated with IFNalpha. MR was achieved in 1 (17 percent), mR in 4 (67 percent) and SD in 1 of 6 patients (17 percent), neither had CR or PD. An initial response was observed after 8-17 weeks of treatment (mean 12.7 weeks). Fever occurred in 4 patients (67 percent). Flu-like symptoms in 3 patients (50 percent) related to IFNalpha were the most common adverse events. Mean follow-up was 6.3 months. The differences in response to treatment between PLD and IFNalpha, in general, were significant with p < 0.05 (T-test for independent samples). Comparing weeks to respond and treatment efficiency data were significant with p < 0.001 (Fisher's exact): response to PLD was up to one-third faster than IFNalpha. Calculating different stages of response (MR, CR, etc.), PLD also was clearly superior (p = 0.018) to IFNalpha (Fisher's exact). CONCLUSION: This retrospective analysis of patients with classic KS confirms the efficacy and safety of PLD. The benefits of PLD, including the monthly application, the high response even after previous treatments have failed, and the low rate of side effects even in elderly individuals, outweigh the risks. PLD is superior to IFNalpha and should be considered as an promising option in the treatment of advanced classic KS.     

Selenoprotein-deficient transgenic mice exhibit enhanced exercise-induced muscle growth

Dietary intake of selenium has been implicated in a wide range of health issues, including aging, heart disease and cancer. Selenium deficiency, which can reduce selenoprotein levels, has been associated with several striated muscle pathologies. To investigate the role of selenoproteins in skeletal muscle biology, we used a transgenic mouse (referred to as i6A-) that has reduced levels of selenoproteins due to the introduction and expression of a dominantly acting mutant form of selenocysteine transfer RNA (tRNA[Ser]Sec). As a consequence, each organ contains reduced levels of most selenoproteins, yet these mice are normal with regard to fertility, overall health, behavior and blood chemistries. In the present study, although skeletal muscles from i6A- mice were phenotypically indistinguishable from those of wild-type mice, plantaris muscles were approximately 50% heavier after synergist ablation, a model of exercise overload. Like muscle in wild-type mice, the enhanced growth in the i6A- mice was completely blocked by inhibition of the mammalian target of rapamycin (mTOR) pathway. Muscles of transgenic mice exhibited increased site-specific phosphorylation on both Akt and p70 ribosomal S6 kinase (p70S6k) (P < 0.05) before ablation, perhaps accounting for the enhanced response to synergist ablation. Thus, a single genetic alteration resulted in enhanced skeletal muscle adaptation after exercise, and this is likely through subtle changes in the resting phosphorylation state of growth-related kinases.     

Characterization of daunorubicin-induced apoptosis in retinal pigment epithelial cells: modulation by CD95L

PURPOSE: To characterize daunorubicin-induced cell death in cultured human retinal pigment epithelial (RPE) cells and its modulation by CD95 ligand (CD95L). METHODS: In situ DNA end labeling and an ELISA for histone-associated DNA fragments were used to assess apoptosis. CD95 and CD95L expression were examined by immunohistochemistry, flow cytometry, immunoblot, and RT-PCR. Cell death was measured by crystal violet staining. YVAD- and DEVD-amc cleavage was used to measure caspase-1 and -3-like activity. Total RNA and protein synthesis was measured by incorporation level of [(3)H]-leucine and [(3)H]-uridine. RESULTS: RPE cells expressed both CD95 and CD95L, but only CD95 was expressed at the cell surface. Daunorubicin-induced RPE cell apoptosis was associated with enhanced CD95 and CD95L expression. Enhanced CD95L expression was epiphenomenal to the death process, evidenced by the fact that neutralizing CD95L antibodies failed to modulate daunorubicin cytotoxicity. In contrast, the cytotoxic effects of daunorubicin were synergistically enhanced by exogenous CD95L. Synergy appeared to involve enhanced caspase-3-like activity as well as daunorubicin-mediated inhibition of RNA synthesis. CONCLUSIONS: Apoptosis has been shown to be an important factor in the control of specific cell populations. The synergistic activity of an antiproliferative agent, daunorubicin, and a cytokine, CD95L, induces apoptosis in RPE cells. Such approaches provide a means to reduce the concentration of chemotherapeutic agents with a small therapeutic window owing to retinal toxicity, such as daunorubicin, in the adjuvant therapy of proliferative vitreoretinopathy.     

A single local injection of recombinant VEGF receptor 2 but not of Tie2 inhibits retinal neovascularization in the mouse

PURPOSE: The purpose of this study was to develop pharmacological therapeutic alternatives for ischemia-induced proliferative retinopathy. METHODS: C57BL/6J mice were placed in 76% oxygen on postnatal day 7 (P7) for 5 days. On P12 recombinant, chimeric vascular endothelial growth factor (sVEGF-R2) or sTie2 was injected intravitreally in one eye. The fellow eye received a control injection. On P17, retinal wholemounts were prepared after perfusion with fluorescein-dextran to quantify the retinopathy. RESULTS: A single intravitreal injection of sVEGF-R2 reduced pathologic vascular changes significantly (p = 0.02). No significant effect was observed after intravitreal application of sTie2 (p = 0.07), although Ang-2 was upregulated in control animals without treatment as neovascularization developed and Ang-1 was constantly transcribed (ratio PCR). CONCLUSIONS: sVEGF-R2 interferes with VEGF signaling via VEGF-R2 receptor. Thus, local application of soluble receptors for angiogenic factors is a possible therapy for proliferative retinopathy. Receptors with a wide range of ligands might prove more useful for local application than those binding few or antagonistic ligands.     

High-resolution laser Doppler perfusion imaging aids in differentiating between benign and malignant melanocytic skin tumours

Malignant melanomas are characterized by heterogeneity and asymmetry as well as by a higher density of blood vessels than benign pigmented tumours. The aim of this study was to evaluate the benefit of high-resolution laser Doppler perfusion imaging (LDPI) in the differential diagnosis of pigmented skin tumours. One-hundred-and-eighty-nine patients were examined with the LDPI, 22 with malignant melanomas, 39 with clinically suspicious dysplastic melanocytic naevi and 27 with basal cell carcinomas. Following examination, the tumours were excised and examined histologically. A control group of 101 melanocytic naevi showed clinically and, with epiluminescence microscopy, definitely benign criteria. These naevi were not excised. In malignant melanomas there was a 3.6+/-1.5 times higher perfusion than in healthy skin. The corresponding figures for clinically suspicious melanocytic naevi and basal cell carcinomas were 2.2+/-1.1 and 2.0+/-0.7, respectively. The increase in flow in malignant melanomas was significantly higher than in clinically suspicious melanocytic naevi and basal cell carcinomas (p < 0.001). All malignant melanomas showed at least 1.8 times higher flow values than healthy skin. When this value is taken as the basis for the diagnosis "benign or malignant", the LDPI proved a sensitivity of 100% and a specificity of 85%. If only the distinction between malignant melanomas and clinically suspicious naevi is considered, the specificity is reduced to 48%. There was no correlation between tumour thickness and increase in the mean perfusion of malignant melanomas (r = 0.14; p = 0.5). High-resolution LDPI can be used as an additional automatic screening method.