Community ecology of helminth parasitism in an insular passerine avifauna.

Three hundred and thirty specimens of 7 species of passerine birds from South Bass Island, Ottawa County, Ohio, were examined for helminth parasites. The total number of helminth specimens collected was 4,333. Forty-one helminth taxa were identified. Ten species of helminths were identified as having foci of infection on the island. An index of association for these 10 species is presented. The low association revealed between helminth species utilizing common species of intermediate hosts indicated that a single intermediate host specimen is likely to harbor infective stages of only one species of parasitic helminth. An index of similarity is presented to express the species importance relationships of the helminth faunas of the 7 species of birds: red-winged blackbirds (Agelaius phoeniceus), blue jays (Cyanocitta cristata), brown-headed cowbirds (Molothrus ater), common grackles (Quiscalus quiscula), house sparrows (Passer domesticus), starlings (Sturnus vulgaris), and robins (Turdus migratorius). The results reveal that competition between these avian species for invertebrate food resources helps to maximize the transmission of those helminth populations which utilize these same invertebrates as intermediate hosts. The aggregation of birds into mixed feeding flocks insures a heavy loading of the feeding grounds with agents infective for the invertebrate populations.     

Apport de la tomographie par émission de positons au 18F-fluorodéoxyglucose (TEP-FDG) dans la prise en charge du cancer du canal anal

ObjectiveTo evaluate the contribution of FDG-PET in the management of anal carcinoma, with special emphasis on its impact on therapeutic strategy.Materials and methodsFrom March 2005 to August 2008, 48 PET were performed on 43 patients with anal epidermoid carcinoma, in initial staging (IS: 20 exams), therapeutic response assessment (TRA: 11), and recurrence assessment (RA: 17). We compared initial therapeutic strategies defined on conventional assessment results, to final ones chosen after PET.ResultsPET revealed lesions that were undetected by conventional investigation in 23% of cases (IS: 25%; TRA: 18%; RA: 23%) and cleared suspicious lesions in 21% of cases (IS: 10%; TRA: 18%; RA: 35%). It influenced the therapeutic strategy, and sometimes even modified it radically, in 44% of cases (IS: 35%; TRA: 54%; RA: 47%). This therapeutic impact was stronger in settings with diagnostic ambiguity, in which PET allowed to specify the diagnosis and to orientate consequently the therapeutic choice.ConclusionPET is interesting in the management of anal carcinoma, especially in uncertain diagnostic settings, in which the metabolic information brought allows to influence the therapeutic choice in almost half of the cases.     

A new, transportable ergometer for the measurement of musculotendinous stiffness during wrist flexion.

We present here a new, dedicated mechanical device for monitoring quick-release movements of the wrist. The ergometer was designed to easily assess musculotendinous properties during wrist flexion. Maximal voluntary contractions (MVC) and quick-release (QR) movements during wrist flexion were performed on 14 subjects. A validation of the ergometer, using a test-retest methodology, was performed to assess its reliability and sensitivity. The device has been technically and biomechanically validated in a range of situations, including inertia measurement (mean inertia was found 0.0119+/-0.0012 N m s(2) rad(-1)) and appearance of the unloading reflex. Our results indicate that the device provides highly reliable, sensitive evaluation of wrist muscle stiffness (intraclass correlation coefficient for inertia, maximal voluntary contraction and stiffness index were 0.873, 0.994 and 0.930, respectively). Its portability facilitates measurement of the influence of repetitive, occupational activity on the musculotendinous complex of the wrist flexors.     

In vitro assessment of three fibrolytic enzyme preparations as potential feed additives in equine diets

A series of in vitro experiments were conducted to assess three fibrolytic enzyme preparations as potential feed additives in equine diets. The three fibrolytic enzyme preparations were a concentrated cellulase (E1), an acid cellulase (E2) and a concentrated xylanase (E3). The enzymes were evaluated on their ability to modify the cell wall fraction of high-temperature dried lucerne (HTL) under various experimental conditions including differences in temperature, pH, incubation period, substrate levels and particle size to enable selection of the enzyme preparation most effective in the hydrolysis of lucerne. Results showed enzyme activities (as measured by reducing sugar assays) to be greatest at 50 °C, pH 5 and over an incubation period of greater than 20 h. E1 exhibited the greatest effect on total monosaccharide release from the HTL compared to E2 and E3. Moreover, dry matter (DM) and total non-starch polysaccharide (TNSP) losses were also greater in HTL treated with E1 compared to E2 and E3. Therefore, since the cell wall fraction of HTL contained substantial amounts of cellulose, the enzyme with the highest cellulase activity (Enzyme 1) was most effective in hydrolysing the cell walls of HTL. Consequently, it would appear that the application of exogenous fibrolytic enzyme preparations to forages requires the chemical characterisation of the target forage to enable selection of enzymes that are (a) most suitable to degrade the cell wall components of the candidate forage and (b) effective under field conditions.     

The distribution of Escherichia coli recA protein bound to duplex DNA with single-stranded ends

A short single-stranded tail on one end of an otherwise duplex DNA molecule enables recA protein, in the presence of ATP and MgCl2, to form a complex with the DNA which extends into the duplex portion of the molecule. Nuclease protection studies at a concentration of MgCl2 which permits homologous pairing showed that cleavage by restriction endonucleases at sites throughout the duplex region was inhibited, whereas digestion by DNase I was not affected. These results indicate that recA protein binds to the duplex portion of tailed DNA allowing access by DNase I to a random sample of the many sites at which it cleaves, but providing limited protection of the relatively rare restriction sites. Electron microscopy revealed that the recA nucleoprotein complex with duplex DNA is indeed a segmented or interrupted filament that, with time, extends further from the single-stranded tail into the duplex region. recA protein binding extended into the duplex region more rapidly for duplexes with 5' tails than for those with 3' tails. These observations show that recA protein translocates from a single-stranded region into duplex DNA in the form of a segmented filament by a mechanism that is not strongly polarized.