Immunogenic or pathogenic factors of recombinant proteins (rBCSP20, rBCSP-31, and rBCSP45 of Brucella abortus strain 19) for mice were compared with factors of a proteinase K-treated lipopolysaccharide extracted from B abortus strain 2308. Mice were vaccinated with 4 products, using different inoculation schedules and were challenge exposed with a virulent culture of B abortus strain 2308. Blood samples were collected 2 weeks after vaccination and at necrospy and sera were obtained. Spleens were cultured for B abortus at necropsy (3 to 4 weeks after challenge exposure). Mice given proteinase K-treated lipopolysaccharide alone or in conjunction with rBCSP20 or rBCSP45 proteins were protected, but mice given rBCSP31 on the same day as challenge exposure were not. Vaccination with recombinant proteins alone neither provide protection nor significantly (P greater than 0.05) increase the pathogenic effect of the challenge-exposure culture. Seemingly, rBCSP31 might be a virulence factor of B abortus.

Colostral volume and IgG and IgM concentrations were determined in 6 multiparous mares at foaling and then every 2 hours from 16 to 20 hours after parturition. Serum IgG and IgM concentrations at foaling also were determined in each mare. The rate of mammary secretion was 292 +/- 26 ml/h (range, 202 to 389 ml/h), and the colostral volume was 5.1 +/- 0.5 L (range, 3.2 to 7.0 L). The colostral IgG and IgM contents were 440 +/- 106 g (range, 199 to 855 g) and 3.1 +/- 0.9 g (range, 0.7 g to 7.1 g), respectively. There was no significant correlation between serum and initial colostral IgG and IgM concentration or between serum and total colostral IgG or IgM values. The colostral IgG and IgM concentrations at foaling correlated well with the total colostral IgG and IgM contents, respectively. The initial 250 ml of colostrum contained 10 +/- 1.4% (range, 6.0 to 13.9%) and 6 +/- 1.0% (range, 2.4 to 8.5%) of the total IgG and IgM contents, respectively, and the initial 500 ml of colostrum contained 20 +/- 2.7% (range 12.0 to 27.1%) and 14 +/- 1.2% (8.2 to 17%) of the total colostral IgG and IgM contents, respectively.

A transretinal method for recording the summed potentials generated by photoreceptors of the isolated canine retina in vitro is reported. Pieces from 10 retinas of 5 clinically and visually normal dogs were maintained in a recording chamber and superperfused with a modified cell culture medium. Sodium glutamate added to the medium eliminated electrical responses from retinal glia and allowed the summed receptor potentials to be recorded. The response to flashes of light consisted of a negative potential, which increased in amplitude in a graded manner and in complexity with increased stimulus intensity. The response was similar in waveform to that reported in other vertebrate species, using intracellular and extracellular techniques. This method of recording the mass transretinal receptor potentials in vitro will be of value for investigating abnormal photoreceptor functions in dogs in the early stages of inherited retinal degeneration.

To investigate the potential role of sympathetic nerves in preventing pronounced increases in cerebral blood flow, we evaluated the effects of abrupt hypertension on the cerebral circulation of newborn pigs with intact cerebral sympathetic innervation and after cerebral sympathetic denervation. Epinephrine infusion was used to induce abrupt increases in mean (+/- SEM) arterial pressure (innervated pigs, 62 +/- 3 mm of Hg to 115 +/- 3 mm of Hg; denervated pigs, 71 +/- 4 mm of Hg to 132 +/- 4 mm of Hg) that remained increased for the 3 minutes of the study. Abrupt hypertension increased blood flow to all brain regions. In denervated pigs, the increased flow to the cerebrum was prolonged, compared with that in pigs with intact sympathetic innervation. Differences between pigs of the innervated and denervated groups were not apparent, with respect to blood flow to any other region (caudate region, brain stem, cerebellum). In newborn pigs, sympathetic nerves may attenuate hypertension-induced increases in blood flow to the cerebrum, but do not appear to affect flow to the rest of the brain.

Mastitis was induced in 4 lactating cows by inoculation of Klebsiella pneumoniae (10(7) organisms/ml) via the teat canal. Sterile isotonic saline solution (1 ml) was instilled into designated control quarters via the teat canal. Changes in milk leukotriene B4 and C4 (LTB4, LTC4) concentrations, milk somatic cell counts, and milk bovine serum albumin concentration were monitored over a 24-hour postinoculation period. Milk LTB4 concentration before inoculation in control quarters and quarters later to be infected was 376 +/- 45 and 326 +/- 56 pg/ml of milk, respectively. A significant (P less than 0.05) increase in milk LTB4 concentration in the infected quarters was first observed at postinoculation hour 6, and milk LTB4 concentration in infected quarters generally remained significantly high through postinoculation hour 14. Thereafter, milk LTB4 concentration in infected quarters was not significantly different from the concentration in control quarters. Measurable amounts of LTC4 were not detected in the milk of either control or infected quarters. Milk bovine serum albumin concentration in the infected quarters generally was high throughout the study, as were milk somatic cell counts. The results of this study suggested that LTB4 contributes to the pathogenesis of bovine mastitis.

Male Holstein calves were each inoculated with 350,000 sporulated oocysts of Eimeria bovis. Two calves were given decoquinate (0.5 mg/kg of body weight) continuously in dry feed for 29 days, and 2 calves each were given 0.5, 1, or 1.5 mg of decoquinate/kg on an every 2nd-or 3rd-day schedule for 29 days. Calves given decoquinate continuously did not discharge oocysts but had slightly loose feces. In general, the number of oocysts discharged increased and fecal consistency decreased as the time between feeding of medicated feed increased. Calves given 0.5 or 1.5 mg of decoquinate/kg every 3rd day discharged more oocysts and had more diarrhea than did calves given 1 mg of decoquinate/kg every 3rd day. At postinoculation day 29, calves were euthanatized. At necropsy, intestinal tissues of calves given decoquinate were mostly normal. Apparently, reduced infections along with the elapsed time were sufficient to resolve most intestinal lesions caused by the coccidia. Decoquinate was most effective when fed continuously at 0.5 mg/kg. However, when fed at 1 or 1.5 mg of decoquinate/kg every 2nd day or 1.5 mg of decoquinate/kg every 3rd day, oocyst production was reduced and clinical coccidiosis was prevented.

Uveitis was induced in dogs by intracameral injection of canine lens protein. The lipoxygenase inhibitors phenidone and norhydroguaiaretic acid, and dimethyl sulfoxide decreased fibrin production at 0.5 and 1 hour after induction uveitis. Phenidone and norhydroguaiaretic acid also inhibited the initial increase intraocular pressure early in the course of inflammation. Leukotriene B4 in the aqueous was measured by use of radioimmunoassay at 1 hour after inflammation. In control dogs, 230 to 1,700 pg of leukotriene B4/ml was measured; in dogs treated with phenidone, leukotriene, B4 was not measured.

We studied the antibody responses to transmissible gastroenteritis (TGE) in serum, colostrum, and milk from sows vaccinated with 2 attenuated (1 IM and 1 oral-IM) and 1 nonattenuated live vaccines and the relationship of these responses with the survivability of the sow's suckling pigs after challenge exposure with virulent TGE virus. Contrary to previous studies, the anti-TGE virus-neutralizing geometric mean titers (GMT) in the milk of sows vaccinated with attenuated vaccines at 3 and 5 days of lactation were similar to that found in the colostrum. Colostral and serum antibody titers were highest in sows given 2 injections of the IM attenuated vaccine. Half of the sows given the oral-IM attenuated vaccine did not seroconvert after 2 oral doses. Only sows vaccinated with the nonattenuated live vaccine had milk GMT that remained high for 21 days after farrowing. The linear relationship between colostral GMT and percentage of survivability of suckling pigs challenge exposed at 3 days of age was significant (P less than 0.05), although the relationship between serum GMT and percentage of survivability and the relationship between milk GMT and percentage of survivability were not significant (P greater than 0.10). The linear relationship between colostral (P less than 0.10) or pre-challenge exposure milk (P less than 0.05) GMT and percentage of survivability of suckling pigs challenge exposed at 5 days of age was significant. We have no adequate explanation for the relatively low colostral GMT, the relatively high milk GMT at 3 and 5 days of lactation in vaccinated sows, or the lack of significant linear relationship between milk GMT and survivability of pigs challenge exposed at 3 days of age.

Antigenic relationship of Actinobacillus (Haemophilus) pleuropneumoniae serotype-8 isolates with other serotypes was studied, using tube agglutination, with and without 2-mercaptoethanol, indirect hemagglutination with and without 2-mercaptoethanol, ring precipitation, coagglutination, and immunodiffusion tests. Serotype-8 isolates possessed serotype-specific, group-specific common antigens cross-reactive with serotypes 3 and 6 and species-specific common antigens cross-reactive with other serotypes. Absorption studies were done to study the antigenic relationship of serotype 8 with serotypes 3 and 6. Rabbit antisera against whole-cell (WC) suspensions of reference strains of serotypes 3, 6, and 8 were used for absorption studies with WC and boiled WC suspensions of homologous and heterologous serotypes. Unabsorbed and absorbed sera were tested for antibodies against WC and boiled WC antigen preparations of serotype 8, using various serotests. Absorption studies revealed that serotype-8 strains possessed 2 main types of epitopes, one of which was serotype-specific and did not have cross-reactivity with other serotypes. The second type of epitopes was group specific and was cross-reactive with serotypes 3 and 6.

Purified O chain of Brucella abortus was passively attached to polystyrene to differentiate antibody responses of cattle vaccinated with B abortus strain 19 from those of naturally infected cattle. In the indirect assay, using O polysaccharide as antigen, a single serum dilution was used and mouse monoclonal antibody to bovine L chain conjugated with horseradish peroxidase was the detection reagent. Measurable antibody was not found in sera of vaccinated cattle, except for 3 sera from cattle that were persistently infected with strain 19. Sera from 25 cattle infected with pathogenic strains contained antibody on the basis of results of indirect enzyme immunoassay, using smooth lipopolysaccharide or O chain as antigens, or results of competitive enzyme immunoassay, using the O-chain antigen. Results in sera from calves with experimentally induced Yersinia enterocolitica serotype 0:9 infection or inoculated with a low dose of B abortus strain 2308 were comparable with those in sera of cattle that were vaccinated with strain 19. The data correlated with those from competitive enzyme immunoassay, using one serum dilution and horseradish peroxidase-conjugated mouse monoclonal antibody to smooth lipopolysaccharide. On the basis of results of the indirect enzyme immunoassay, all sera (except those samples obtained before inoculation) contained antibody to smooth lipopolysaccharide.