Selection Of A Novel Aptamer Against Vitronectin Using Capillary Electrophoresis And Next Generation Sequencing

Breast cancer (BC) results in ≃40,000 deaths each year in the United States and even among survivors treatment of the disease may have devastating consequences, including increased risk for heart disease and cognitive impairment resulting from the toxic effects of chemotherapy. Aptamer-mediated drug delivery can contribute to improved treatment outcomes through the selective delivery of chemotherapy to BC cells, provided suitable cancer-specific antigens can be identified. We report here the use of capillary electrophoresis in conjunction with next generation sequencing to develop the first vitronectin (VN) binding aptamer (VBA-01; Kd 405 nmol/l, the first aptamer to vitronectin (VN; Kd = 405 nmol/l), a protein that plays an important role in wound healing and that is present at elevated levels in BC tissue and in the blood of BC patients relative to the corresponding nonmalignant tissues. We used VBA-01 to develop DVBA-01, a dimeric aptamer complex, and conjugated doxorubicin (Dox) to DVBA-01 (7:1 ratio) using pH-sensitive, covalent linkages. Dox conjugation enhanced the thermal stability of the complex (60.2 versus 46.5°C) and did not decrease affinity for the VN target. The resulting DVBA-01-Dox complex displayed increased cytotoxicity to MDA-MB-231 BC cells that were cultured on plasticware coated with VN (1.8 × 10⁻⁶mol/l) relative to uncoated plates (2.4 × 10⁻⁶ mol/l), or plates coated with the related protein fibronectin (2.1 × 10⁻⁶ mol/l). The VBA-01 aptamer was evaluated for binding to human BC tissue using immunohistochemistry and displayed tissue specific binding and apparent association with BC cells. In contrast, a monoclonal antibody that preferentially binds to multimeric VN primarily stained extracellular matrix and vessel walls of BC tissue. Our results indicate a strong potential for using VN-targeting aptamers to improve drug delivery to treat BC

Effects of temperature, shear rate and processing on the rheological properties of salep drink

The effects of shear rate, temperature and processing on the rheological properties of commercial salep drinks (UHT processed in liquid form, powdered forms both instant and traditionally cooked type) are investigated. The empirical power law model is used for the determination of the flow behavior and consistency index. Apparent viscosity of salep drink decreased with increasing shear rate. The salep drink exhibited a pseudoplastic or shear thinning behavior. Processing affected the flow behavior and consistency indices significantly (p ≤0.05). The flow behavior index of samples was in the range of 0.51-0.74 while the consistency index changed in the range of 0.14-2.68 Pa.sn. The lowest flow behavior index and the highest consistency index value are determined with the instant salep drink, while the highest K value was recorded for it. The flow behavior index increased and the consistency index decreased with processing temperature. In sensory analysis, salep drinks were evaluated for flavor, consistency and overall acceptability. A single rheological model is developed to express combined effects of shear rate (by Power law model) and temperature (by Arrhenius equation) on the apparent viscosity of an instant salep drink preferred by the sensory panelists in all samples. This study is expected to standardize the product formulation and facilitate equipment and process design

Survey of aflatoxin contamination of dried figs grown in turkey in 1986

PubMed ID: 2113011A total of 284 dried fig samples, collected from fields during drying, and from warehouse and processing units in the Aegean region of Turkey in 1986, were examined for aflatoxin contamination. Aflatoxin B1, B2, and G1 were detected in 4, 2, and 2% of the samples, respectively, which were of the lower grade of figs taken from the drying stage. The average aflatoxin levels in positive samples were estimated to be 112.3 (B1), 50.6 (B2), and 61.4 ng/g (G1). The samples collected from storage (64 samples) and processing units (14 samples) contained no aflatoxins. The results of this survey show that aflatoxin contamination of Turkish dried figs in 1986 was highly correlated with the poorer grade of fig. © 1990 Taylor & Francis Ltd.North Atlantic Treaty OrganizationThis investigation forms a part of the research project coordinated by Turkish Scientific and Industrial Research Institute (TUBITAK) with the aid of NATO, whom the authors gratefully acknowledge. -