Comparison of a commercial enzyme-linked immunosorbent assay with hemagglutination inhibition assay for serodiagnosis of swine influenza virus (H1N1) infection.

A commercial indirect swine influenza virus (SIV) H1N1 enzyme-linked immunosorbent assay (ELISA) was compared with the hemagglutination inhibition (HI) assay by testing 72 samples from experimentally infected pigs and 780 field samples of undefined SIV status. The HI assay was performed using SIV isolates A/Swine/IA/73 for H1N1 and A/Swine/IA/8548-1/98 for H3N2. The ELISA used an SIV isolated in 1988. The results showed that HI and ELISA detected an antibody in 11 and 6, respectively, of 72 serum samples collected from pigs experimentally infected with a 1992 SIV isolate (A/Swine/IA/40776/92). The presence of antibodies in these experimental samples was confirmed by HI tests in which all 72 samples were positive against the homologous virus, a more recent H1N1 SIV isolate (A/Swine/NVSL/01) supplied by National Veterinary Services Laboratories, Ames, Iowa, and a 1999 H1N1 isolate currently used in a commercial vaccine. On testing 780 field samples, an overall agreement of 85.5% was generated between the HI and ELISA. This study demonstrated that the ELISA is a useful serodiagnostic screening test at herd level for detecting swine antibodies against SIV. However, a new SIV isolate representing current SIV strains circulating in the field is needed to replace the older isolates used in the HI and ELISA to increase the test accuracy for serodiagnosis of SIV.     

Transitional cell carcinomas in four fishing cats (Prionailurus viverrinus).

Transitional cell carcinomas (TCC) of the urinary bladder were diagnosed in four related fishing cats (Prionailurus viverrinus). The major clinical sign in each case was persistent hematuria unresponsive to medical therapy. Cystotomy and biopsy provided an antemortem diagnosis in three of the fishing cats before euthanasia because of progression of clinical signs. The diagnosis was made in the fourth cat after euthanasia because of renal failure. Hematuria improved temporarily in one of the cats diagnosed antemortem and treated with piroxicam and carboplatin. Attempts to isolate a herpesvirus in two of the cats failed. Histopathologic appearance of the TCC was similar to that described for other species. TCC metastasis to the lungs was noted at necropsy in one cat; metastatic disease was not noted in the other fishing cats on gross or histopathologic examination. TCC of the urinary bladder appears to be more prevalent in fishing cats than in other species of domestic or nondomestic felids.     

Exploring the limits of crop productivity: beyond the limits of tipburn in lettuce.

The productivity of lettuce in a combination of high light, high temperature, and elevated CO2 has not been commonly studied because rapid growth usually causes a calcium deficiency in meristems called tipburn, which greatly reduces quality and marketability. We eliminated tipburn by blowing air directly onto the meristem, which allowed us to increase the photosynthetic photon flux (PPF) to 1000 micromoles m-2 s-1 (57.6 mol m-2 d-1); two to three times higher than normally used for lettuce. Eliminating tipburn doubled edible yield at the highest PPF level. In addition to high PPF, CO2 was elevated to 1200 micromoles m-2 mol-1, which increased the temperature optimum from 25 to 30 degrees C. The higher temperature increased leaf expansion rate, which improved radiation capture and more than doubled yield. Photosynthetic efficiency, measured as canopy quantum yield in a whole-plant gas exchange system, steadily increased up to the highest temperature of 32 degrees C in high CO2. The highest productivity was 19 g m-2 d-1 of dry biomass (380 g d-1 fresh mass) averaged over the 23 days the plants received light. Without the limitation of tipburn, the combination of high PPF, high temperature, and elevated CO2 resulted in a 4-fold increase in growth rate over productivity in conventional environments.     

A comparative review of the mammalian toxicity of Bacillus thuringiensis-based pesticides

The extensive mammalian toxicity studies performed to support the safety of Bacillus thuringiensis-containing pesticides clearly demonstrate that the tested isolates are not toxic or pathogenic. Toxicity studies submitted to the US Environmental Protection Agency to support the registration of B. thuringiensis subspecies have failed to show any significant adverse effects in body weight gain, clinical observations, or upon necropsy. Infectivity/pathogenicity studies have shown that the intact rodent immune system responds as expected to eliminate B. thuringiensis gradually from the body after oral, pulmonary or intravenous challenge. Similar clearance patterns were observed with B. subtilis and B. sphaericus, which also were non-toxic to test animals. The results also indicate that the currently used protocols for toxicity/pathogenicity evaluations of micro-organisms in laboratory animals have provided useful and necessary information for risk assessment. The study results raise the issue, however, of whether some reduced set of toxicily/pathogenicity studies could be required for new B. thuringiensis isolates of already registered subspecies, and whether this reduced data set would also apply to subspecies not yet registered as pesticidal active ingredients.     

Segmental lung lobe torsion in a 7-week-old Pug

Case summary: A 7‐week‐old, intact female Pug was referred with an acute history of expiratory dyspnea, tachypnea, and pyrexia. Radiologic evaluation revealed bilateral pleural effusion and a poorly demarcated area of soft tissue opacity cranial to the heart. The presence of air bronchograms in the cranial lung lobes suggested alveolar parenchymal pathology consistent with pulmonary edema, congestion, or cellular infiltration. Exploratory thoracotomy revealed a segmental torsion of the left cranial lung lobe. The affected lobe was removed and the puppy recovered uneventfully. Unique information: Lung lobe torsion tends to occur more frequently in mature large breed dogs at a mean age of 3 years. The age, breed, and segmental nature of the torsion in the reported case are contrary to most of the previously documented cases of lung lobe torsion. To the authors' knowledge, this is the first report of lung lobe torsion in a 7‐week‐old dog.     

Management of forages for stocker cattle.

Successful grazing management of stockers requires knowledge of plant growth characteristics. Maintaining abundant leaf area is critical to support photosynthesis and plant growth as well as to provide nutritious grazing for the animals. Controlling stocking rate, stock density, and lengths of grazing and recovery periods can optimize individual animal rates of gain and gain per acre while maintaining pasture productivity. Various plant resources, perennial and annual, can be used strategically to provide the quantity and quality of forage needed by stockers throughout the year.