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Selected AbstractsLabel-Free and Ultra-Low Level Detection of Salmonella enterica Serovar Typhimurium Using Electrochemical Impedance SpectroscopyELECTROANALYSIS, Issue 20 2009Jeffrey Abstract An immunosensor for rapid and low level detection of the bacterial pathogen Salmonella enterica Serovar Typhimurium was designed and developed based upon label-free electrochemical impedance spectroscopy and correlated to viable cell counts. The immunosensor was fabricated by electroplating gold onto a disposable printed circuit board (PCB) electrode by immobilizing monoclonal antibody (MAb) specific against Salmonella typhimurium cell surface lipopolysaccharide (LPS) onto the surface of the electrode. Use of mass-fabricated and electroplated PCB electrodes allowed for disposable, highly sensitive, and rapid detection of Salmonella in an aqueous environment. Results demonstrate that in purified solution, Salmonella can be detected as low as 10 CFU in a 100,,L volume and label-free and rapid manner in fewer than 90,s. The cost effective approach described here can be used for detection of pathogens with relevance for healthcare, food, and environmental applications. [source] INTEGRATING INTENSIVE AQUACULTURE OF CHONDRACANTHUS EXASPERATUS, THE TURKISH TOWEL SEAWEEDJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Waaland, J. R. Department of Botany, University of Washington, Seattle, WA 98195 USA A new, high value product from the Turkish Towel Seaweed, Chondracanthus exasperatus, was developed recently by a Seattle company. However, Washington State has a long term moratorium on commercial seaweed harvesting from wild populations so there is renewed interest in intensive cultivation of this species. The initial phase of this research was conducted at Mukilteo, Washington. There, strategies for long term cultivation in tanks were tested, and a custom cultivation tank design was developed for pilot scale cultivation research at a site on the shore of Clam Bay near Manchester, Washington. Long term cultivation is now being tested in tanks of up to 5000 L volume supplied with natural seawater, seawater supplemented with nutrients, and seawater effluent from nearby Pacific Halibut culture tanks. Seawater from Clam Bay is naturally rich in nutrients from tidal driven upwelling and nearby commercial salmon mariculture operations. Supplemental nutrients (commercially available "f/2" enrichment) and halibut culture tank effluent have both been tested for their ability to support C. exasperatus growth with relatively low seawater turnover rates. Compared to seawater at the site, Halibut tank effluent differs in both nutrient composition and quantities. Initial results indicate that halibut tank effluent is a satisfactory source of nutrients for C. exasperatus in intensive culture and that the Turkish Towel Seaweed scrubs significant quantities of nutrients from halibut tank effluent. [source] Validation of a Feeding Stimulant Bioassay Using Fish Hydrolysates for the Pacific White Shrimp, Litopenaeus vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2009Michael Grey A protocol for testing feeding stimulants on Pacific white shrimp, Litopenaeus vannamei, is described. Thirty-five rectangular tanks (55 L volume) served as the test system into which ten 5,6 g shrimp were stocked. Every tank contained two bowls, each of which contained either 25 feed pellets of a Reference Diet or Test Diet (consisting of the Reference Diet with one test ingredient added). After 1 h, the difference between the number of pellets consumed of the Test Diet and the Reference Diet was used as the Response. Each of the four Test Diets contained a different salmon hydrolysate made from by-products of the Alaska fish processing industry (included at 50 g/kg). A fifth commercial shrimp diet was also tested. Each Test Diet was tested against the Reference Diet over a 4-d period in seven replicate tanks. The data were subjected to a one-way ANOVA and a confidence interval for each treatment response was calculated. The confidence interval was used to assess the test ingredient as a feeding stimulant. Treatment means were compared using Tukey's test (, = 5%). All the hydrolysates tested were found to act as feeding stimulants. [source] The Neovessel Occlusion Efficacy of 151 -Hydroxypurpurin-7-Lactone Dimethyl Ester Induced with Photodynamic TherapyPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010Siang Hui Lim In this study, the photodynamic therapy (PDT) induced efficacy of a semi-synthesized analogue 151 -hydroxypurpurin-7-lactone dimethyl ester or G2, in terms of chick chorioallantoic membrane blood vessel occlusion was evaluated in reference to verteporfin. Early formulation studies showed that G2 prepared in a system of cremophor EL 2.5% and ethanol 2.5% in saline was biocompatible up to 20 ,L volume of injection. Following injection, G2 accumulation peaked within the first minute and its extravasation from intra- to extra-vascular occurred somewhat slower as compared with verteporfin. In the PDT study, closure of capillaries and small neovessels was observed with 4 ,g per embryo of G2 and a light dose of 20 J cm,2 at a fluence rate of 40 mW cm,2 filtered at 400,440 nm,a result that may be considered optimum for the treatment of age-related macular degeneration (AMD). Also, partial occlusion of the large vessels was observed using the same dose of G2 and light,an effect which is desirable for cancer treatment. From this study, we conclude that G2 has the potential to be developed as a therapeutic agent for photodynamic treatment for AMD and cancer. [source] Multienzyme catalysis in microfluidic biochipsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2003Moo-Yeal Lee Abstract The attachment of enzymes to glass microfluidic channels has been achieved using a highly reactive poly(maleic anhydride- alt -,-olefin) (PMA)-based coating that is supplied to the microchannel in a toluene solution. The PMA reacts with 3-aminopropyltriethoxysilane groups linked to the glass surface to form a matrix that enables additional maleic anhydride groups to react with free amino groups on enzymes to give a mixed covalent,noncovalent immobilization support. Using a simple T-channel microfluidic design, with reaction channel dimensions of 200 ,m wide (at the center), 15 ,m deep, and 30 mm long giving a reaction volume of 90 nL, soybean peroxidase (SBP) was attached at an amount up to 0.6 ,g/channel. SBP-catalyzed oxidation of p -cresol was performed in aqueous buffer (with 20% [v/v], dimethylformamide) containing H2O2, with microfluidic transport enabled by electroosmotic flow (EOF). Michaelis,Menten kinetics were obtained with Km and Vmax values of 0.98 mM and 0.21 ,mol H2O2 converted/mg SBP per minute, respectively. These values are nearly identical to nonimmobilized SBP kinetics in aqueous,DMF solutions in 20-,L volumes in 384-well plates and 5-mL reaction volumes in 20-mL scintillation vials. These results indicate that SBP displays intrinsically native activity even in the immobilized form at the microscale, and further attests to the mild immobilization conditions afforded by PMA. Bienzymic and trienzymic reactions were also performed in the microfluidic biochip. Specifically, a combined Candida antarctica lipase B,SBP bienzymic system was used to convert tolyl acetate into poly(p -cresol), and an invertase,glucose oxidase SBP trienzymic system was used to take sucrose and generate H2O2 for SBP-catalyzed synthesis of poly(p -cresol). © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 20,28, 2003. [source] Prospective evaluation of cell kinetics, yields and donor experiences during a single large-volume apheresis versus two smaller volume consecutive day collections of allogeneic peripheral blood stem cellsBRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2003Charles D. Bolan Summary. We report cell kinetics, yields and donation experiences of 20 demographically matched allogeneic peripheral blood stem cell (PBSC) donors who were prospectively assigned to undergo either a single 25 l or two consecutive daily 15 l (15 l × 2) apheresis procedures. Procedures were performed using prophylactic intravenous calcium administration after standard granulocyte colony-stimulating factor (GCSF) mobilization (10 ,g/kg/d). Central line placements (two each), initial CD34 cell counts (0·077 vs 0·078 × 109/l) and yields (7·9 vs 8·1 × 108 CD34 cells) were similar in the two groups; however, 25 l donors spent significantly less time both in the clinic (7·5 vs 10·8 h) and with central venous catheters in place (8·5 vs 29·5 h) than 15 l × 2 donors. End-procedure platelet counts were below 100 × 109/l in one out of 10 25 l donors versus five out of 10 in 15 l × 2 donors (41%vs 53% mean decrease in platelet counts, P = 0·02). PBSC collection efficiency increased by 37% after 15 l of the 25-l volume had been processed, compared with no significant change during 15 l × 2 procedures. Results similar to these prospective findings were also observed in CD34 yields, symptoms and platelet counts in additional 25 l and 15 l procedures performed during the same period and evaluated retrospectively. This study indicates that a single 25-l apheresis procedure results in similar yields and symptoms, but less donor thrombocytopenia and inconvenience than two consecutive daily 15-l procedures. [source] Tissue distribution of radioactivity following intranasal administration of radioactive microspheresJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 5 2001J. E. Eyles The aim of this study was to increase understanding of the kinetics of microparticle distribution and elimination following intranasal application. To do this we investigated the in-vivo distribution of radioactivity following intranasal instillation of scandium-46 labelled styrene-divinyl benzene 7-,m-diameter microspheres. Groups of BALB/c mice received 0.250 mg (47.5 kBq) particles suspended in either 50-,l or 10-,l volumes of phosphate buffered saline. The in-vivo distribution of radioactivity was influenced by the volume of liquid that was used to instil the microsphere suspension. Comparatively large (50 ,l) administration vehicle volumes resulted in substantial bronchopulmonary deposition (, 50% of administered dose). Intranasal instillation of microspheres suspended in 10-,l volumes tended to restrict particle deposition initially to the nasal cavity. For both administration vehicle volumes tested, the radioactivity per unit mass of excised nasal-associated lymphoid tissue (NALT) was found to be consistently elevated relative to other tissues. This corroborates the findings of other workers who have previously identified NALT as an active site of microparticle accumulation following intranasal application. Elimination via the alimentary canal was the principal fate of intranasally applied radiolabeled material. No significant concentration of radioactivity within excised gut-associated lymphoid tissue (GALT) (Peyer's patches) was noted. At latter time points we observed, in mice that received the 50-,l volume particle suspension nasally, accumulation of potentially relevant quantities of radioactivity in the liver (0.3% after 576 h) and spleen (0.04% after 576 h). Thus, our data corroborate the notion that epithelial membranes in the lung are probably less exclusive to the entry of microparticulates into systemic compartments than are those mucosae in the gastrointestinal tract or nasopharynx. This effect may contribute to the effectiveness of pulmonary delivered antigen-loaded microparticles as humoral immunogens. [source] | |||||||||||||