A sandwich enzyme immunoassay for bovine interferon-γ and its use for the detection of tuberculosis in cattle

An in vitro cellular assay for bovine tuberculosis has recently been developed. This assay detects gamma-interferon released in response to specific antigen in a whole blood culture system. The bio-assay previously described for the detection of bovine gamma-interferon (IFN-gamma) has now been replaced with a sandwich enzyme immunoassay (EIA) which utilises two monoclonal antibodies to bovine IFN-gamma. The EIA detects less than 25pg/ml of recombinant bovine IFN-gamma and is specific for biologically active bovine IFN-gamma; and does not detect bovine alpha or beta interferon. IFN-gamma from sheep, goat and buffalo, but not from pig, deer or man, are also recognised by the EIA. The bovine IFN-gamma EIA when used in conjunction with the whole blood culture system has resulted in a simple, rapid and sensitive in vitro assay for specific cell mediated immune responsiveness to M. bovis infection in cattle.     

Cyclic nucleotide phosphodiesterase: high activity in a mammalian photoreceptor

Purified outer segments of bovine rods exhibit phosphodiesterase activity against adenosine and guanosine cyclic 3',5'-monophosphates (cyclic AMP and cyclic GMP). The enzyme hydrolyzed cyclic GMP more rapidly than cyclic AMP at low substrate concentrations. The presence of high phosphodiesterase activity in this highly specialized organelle suggests that this enzyme may function in control of cyclic nucleotide concentration during visual excitation or adaptation.     

Immunisation against ovine caseous lymphadenitis: correlation between Corynebacterium pseudotuberculosis toxoid content and protective efficacy in combined clostridial-corynebacterial vaccines

Groups of sheep were dosed with vaccines containing Corynebacterium pseudotuberculosis toxoid combined in varying amounts with 5 clostridial antigens. Resistance of the sheep to infection with C pseudotuberculosis was tested at 1, 6 and 12 months after vaccination by infection with pus from ovine lymph glands actively infected with C pseudotuberculosis. The outcome was assessed 3 months after challenge by slaughter and inspection of the sheep for caseous lymphadenitis lesions. Protection was demonstrated by a significant reduction in the proportion of immunised sheep exhibiting lesions compared with control sheep, and by fewer abscesses in affected immunised sheep than in affected control sheep. A positive correlation was found between amount of C pseudotuberculosis toxoid administered and degree of protection obtained. Chromatographically-purified toxoid induced essentially the same protection, suggesting that anti-toxic immunity is the major factor in protection.     

Pathogenesis of marble spleen disease in bursectomized and non-bursectomized ring-necked pheasants following oral inoculation with cell-culture-propagated virus.

Seventy-two 13-week-old ring-necked pheasants were inoculated orally with 5.0 x 10(2) tissue-culture infective dose (TCID) of cell-culture-propagated marble spleen disease virus. Inoculated birds exhibited neither mortality nor clinical disease. Gross and histologic lesions were typical of marble spleen disease. The mean splenic weight was significantly (P less than 0.02) higher in inoculated birds than in controls between 6 and 10 days postinoculation (PI). The histologic splenic lesions, which consisted of reticuloendothelial cell hyperplasia, intranuclear inclusions within reticuloendothelial cells, and lymphoid depletion, were most prominent between 6 and 10 days PI. In a second experiment, 1-day-old pheasants were chemically bursectomized by dosing birds with 1.2 mg cyclophosphamide on 3 consecutive days. At 7 weeks of age, 54 bursectomized birds were inoculated orally with 5.0 x 10(2) TCID of marble spleen disease virus. Gross and histologic lesions were detected in one of the inoculated pheasants, but the mean splenic weight was not significantly different from control birds at any time PI. These results are evidence of the role of the bursa of Fabricius in the pathogenesis of marble spleen disease.     

The influence of age on the response of ring-necked pheasants to infection with marble spleen disease virus.

Ring-necked pheasants that were negative for maternal antibody against type II avian adenoviruses were orally inoculated with 5.0 x 10(2) tissues-culture-infective doses of marble spleen disease (MSD) virus at 1-week intervals through 6 weeks of age, and at 9 and 13 weeks of age. Groups of four virus-inoculated birds and two control birds were necropsied at 4, 6, 8, and 10 days postinoculation, and the spleens were evaluated for gross and microscopic lesions. No lesions consistent with MSD were present in birds inoculated at 1, 2, 3, or 4 weeks of age. A single bird in the group inoculated at 5 weeks of age had gross and microscopic lesions of MSD. Five birds in the group inoculated at 6 weeks of age had lesions of MSD. The patterns of lesion development in the 6-week-old birds were similar to those produced in the 9- and 13-week-old birds inoculated with MSD virus. The reason for the lack of gross or microscopic lesion development during the first 4 weeks of life is unknown.     

Plasma renin activity and aldosterone and vasopressin concentrations during incremental treadmill exercise in horses.

Six untrained mares were subjected to incremental treadmill exercise to examine exercise-induced changes in plasma renin activity (PRA) and plasma aldosterone (ALDO) and plasma arginine vasopressin (AVP) concentrations. Plasma renin activity, ALDO and AVP concentrations, and heart rate (HR) were measured at each step of an incremental maximal exercise test. Mares ran up a 6 degree slope on a treadmill set at an initial speed of 4 m/s. Speed was increased 1 m/s each minute until HR reached a plateau. Plasma obtained was stored at -80 C and later was thawed, extracted, and assayed for PRA and ALDO and AVP values by use of radioimmunoassay. Exercise caused significant increase in HR from 40 +/- 2 beats/min (mean +/- SEM) at rest to 206 +/- 4 beats/min (HRmax) at speed of 9 m/s. Plasma renin activity increased from 1.9 +/- 1.0 ng/ml/h at rest to a peak of 5.2 +/- 1.0 ng/ml/h at 9 m/s, paralleling changes in HR. Up to treadmill speed of 9 m/s, strong linear correlations were obtained between exercise intensity (and duration) and HR (r = 0.87, P less than 0.05) and PRA (r = 0.93, P less than 0.05). Heart rate and PRA reached a plateau and did not increase when speed was increased from 9 to 10 m/s. Plasma ALDO concentration increased from 48 +/- 16 pg/ml at rest to 191 +/- 72 pg/ml at speed of 10 m/s. Linear relation was found between exercise intensity (and duration) and ALDO concentration (r = 0.97, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

SUBDURAL INJECTION OF CONTRAST MEDIUM DURING CERVICAL MYELOGRAPHY

Three patients (1 dog, 2 horses) ae described where myelography was complicated, purportedly by injection of contrast medium into the meninges superficial to the subarachnoid space. Contrast medium injected in this locationin a cadaver tended ot accoumulate dorsally within the vertebarel canal, deep to the dura mate but superficial to the subarachnoid space. The ventral marginof the pooled contrast medium had a wavy or undulating margin and the dorsal margin was smooth. Pooled contrast medium was believed to be sequestered within the structurally weak dural border cell layer between the dura mater and arachnoid membrane, or so-called subdural space.     

Instructional practices at Farm Safety 4 Just Kids (FS4JK) safety day camps

The instructional methods used with 1,347 youth in seven Farm Safety 4 Just Kids (FS4JK) day camp sessions conducted in five states during the summer and fall of 2002 were videotaped. The videotapes, instructor questionnaires, and day camp materials were analyzed using an observation protocol that focused on instructional practices and an interaction analysis of instructor-student talk during the sessions. Results showed that instruction focused on hazard recognition, a high level of participant attention during all the sessions observed, and safety day camp content relevant to rural participants regardless of whether they live or work on a farm. Recommendations for improving instructional practice include better use of print materials, more interactive, participatory activities for students, and reduction of instructor-centered, didactic approaches. Given the high level of students' attention, increased involvement of students in active, participatory approaches might enhance the effectiveness of the instruction by: (1) further engaging students through personalizing hazard recognition, (2) contextualizing reports of injuries, (3) examining the complexities of choosing safe behaviors, and (4) paying more attention to the consequences of injury events. Role-playing, narrative simulations, and other types of interactive and collaborative exercises are instructional approaches that support the inclusion of the pre-event contingencies and post-event consequences that are part of all injury events.