PCR Assessment of HSV-1 Corneal Infection in Animals Treated with Rose Bengal and Lissamine Green B

PURPOSE. In vivo, the ophthalmic dye rose bengal displays profound antiviral effects against herpes simplex virus (HSV)-1, thus limiting its utility in diagnosis of epithelial keratitis when used before viral culture is performed. In contrast, lissamine green B does not possess significant antiviral activity in vivo. To determine whether polymerase chain reaction (PCR) could successfully detect HSV-1 DNA in ocular samples that have been exposed to ophthalmic dyes, animal models were used to observe the presence of infectious HSV-1 and viral DNA in eyes treated with rose bengal or lissamine green B. METHODS. Animals were bilaterally infected with HSV-1 strain H129, and at daily intervals up to 16 days post infection (dpi) rose bengal or lissamine green B was instilled in the left eyes. The right eyes were not treated with dyes. Swabs of the dye-treated and untreated eyes were assayed by PCR for viral infectivity by culture and the presence of DNA specific for a fragment of the HSV-1 DNA polymerase gene. RESULTS. A statistically equivalent number of samples from lissamine green B-treated and untreated eyes were positive by both viral culture and PCR. In contrast, rose bengal significantly decreased the infectious virus present in ocular secretions. A total of 44% and 78% of the rose bengal-treated and untreated eye samples, respectively, were positive by culture from 1 through 16 dpi. PCR was more sensitive than culture for detection of HSV-1 in rose bengal-treated eyes, in that 74% of rose bengaltreated samples were positive by PCR compared with 44% that were positive by culture during the 16-day period studied. It was also noted that both rose bengal and lissamine green B treatments slightly prolonged the period during which viral DNA was detectable in ocular secretions by PCR, possibly because the singlet oxygen produced by these photoreactive dyes compromised ocular cellular, humoral, and nonspecific immune factors allowing viral DNA to persist for slightly longer periods

Integrating size-structured assessment and bioeconomic management advice in Australia's northern prawn fishery

Three species in Australia's northern prawn fishery (Penaeus semisulcatus, P. esculentus, and Metapenaeus endeavouri) are assessed using a size-structured population model that operates on a weekly time-step. The parameters of this multispecies population model are estimated using data on catches, catch rates, length frequency data from surveys and the fishery, and tag release-recapture data. The model allows for the technical interaction among the three species. The results from the multispecies stock assessment are used to calculate the time-series of catches and levels of fishing effort that maximize net present value. The bioeconomic model takes into account costs which are proportional to catches and those which are proportional to fishing effort, as well as fixed costs. The sensitivity of the results is examined by changing the assumptions regarding the values for the economic parameters of the bioeconomic model as well as those on which the assessment are based. The results suggest that fishing effort needs to be reduced in the short term to achieve economic goals, although most stocks are estimated currently to be above the stock size corresponding to maximum sustainable yield. Short-term catches and effort levels are sensitive to model assumptions, and in particular, to trends in prices and costs