The nature of Mycoplasma arthritidis antigens responsible for eliciting protective immunity in rats was studied by inoculation of rats with mycoplasmal components that had been subjected to a variety of physical and chemical treatments. All inocula tested induced good protection against development of clinical illness, as assessed by changes in body weight and appearance of joint swelling and/or temporary hind limb paralysis. Although all preparations stimulated development in inoculated rats of high titer of antimycoplasmal antibodies measured by ELISA, the complement-fixation antibody response was poor and, in some cases, lacking altogether. This indicated that completion-fixation antibodies may not be involved in protecting rats against M arthritidis-induced illness. Protective antigens were stable to heat (100 C for 10 minutes), formalin, and denaturation by sodium dodecyl sulfate (SDS). Inoculation with membrane and soluble cytoplasmic fractions was protective, as was inoculation with 5 M arthritidis fractions separated according to molecular weight by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). For this latter experiment, rat antisera obtained after vaccination, but prior to challenge exposure, were tested by immunoblot analysis against electrophoretically separated M arthritidis membrane proteins. Interestingly, all antisera from these rats recognized antigens migrating far outside the molecular weight range of the cell fractions with which rats were inoculated. This indicated either that the protective antigens may be composed of numerous antigenically related subunits that separated by SDS-PAGE into a variety of molecular weight ranges or that a few major antigens may exist in several forms or phases within a given population of M arthritidis.

Twenty-four dogs with induced, severe chronic renal failure were allotted to 2 groups of 12 each. Group-A dogs were fed a 0.4% phosphorus (P)/0.6% calcium, 32% protein diet, and group-B dogs were fed a 1.4% P/1.9% calcium, 32% protein diet. Dogs were studied over 24 months to determine clinical status, survival, blood biochemical alterations, glomerular filtration rate (GFR), urinary excretion of P and protein, renal morphologic changes, and renal tissue concentrations of calcium, P, and magnesium. Group-A dogs developed statistically significant differences from group-B dogs in several blood biochemical values (PCV and total solids, calcium, P, potassium, sodium, chloride, total CO2 (TCO2), anion gap, and parathyroid hormone concentrations) and in urinary P excretion. Mean (+/- SEM) GFR values in group-A and group-B dogs were nearly identical when diets were initiated (group A = 0.73 +/- 0.05 ml/min/kg of body weight; group B = 0.72 +/- 0.08 ml/min/kg), but significantly (P = 0.0346) lower GFR developed in group-B than in group-A dogs over time. At 24 months, GFR in survivors was 0.83 +/- 0.08 and 0.63 +/- 0.15 ml/min/kg for dogs of groups A and B, respectively. Other measurements favored the hypothesis that P/calcium restriction was beneficial, but values failed to reach statistical significance. Survival was greater at 24 months in group-A than in group-B (7 vs 5) dogs, and renal tissue concentrations of calcium and P were higher in group-B than in group-A dogs. Differences were not detected between groups in urinary excretion of protein and in the type or severity of renal lesions. We conclude that P/calcium restriction at 32% protein intake is beneficial to dogs with chronic renal failure, but that the degree of restriction imposed in group-A dogs of this study did not prevent development of abnormalities. Factors other than dietary P/calcium intake may have a role in progression of renal failure to uremia.

The duration of the incubation period for scrapie, a fatal transmissible neurodegenerative disorder of sheep and goats, is mainly determined by the Sip gene, which has 2 alleles (sA-susceptible and pA-resistant). A diagnostic test is not available to detect scrapie in live animals. We analyzed genomic DNA extracted from frozen sheep brains collected from Cheviot sheep of the United States that had been inoculated with the SSBP/1 scrapie inoculum. Digestion of the DNA with EcoRI or HindIII followed by the addition of a scrapie-associated fibril protein (PrP)-specific marker probe, yielded fragments of 6.8 (e1) and 4.0 (e3) kb, or 5.0 (h1) and 3.4 (h2) kb, respectively. Fragments e1 and h2 were associated with the histopathologic diagnosis of scrapie, and fragments e3 and h1 were associated with survival. A valine/alanine polymorphism within the PrP coding region that resulted in a BspHI site was further used to determine the genotype of these Cheviot sheep. Digestion of polymerase chain reaction fragments with BspHI resulted in an undigested fragment b- (0.840 kb), digested fragments b+ (0.460 and 0.380 kb), or both types of fragments. Survival time of b+/b+ homozygous sheep was significantly (P < 0.01) shorter (218 +/- 26.0 days) than survival time for b-/b- sheep (> 700 days after inoculation). Results indicated that b+ and b- are markers for the Sip sA and pA alleles, respectively. The intermediate duration of the incubation period for heterozygous sheep (b+/b-; 342.9 +/- 25.3 days) indicated that the Sip sA allele is expressed codominantly to the Sip pA allele.

Blood constituents and vascular volume indices were determined in 5 standing horses by use of 2-period crossover experimental design. Horses were either administered hypertonic (2,400 mosm/kg of body weight, IV) or isotonic (300 mosm/kg, IV) saline solution. Each solution was administered at a dosage of 5 ml/kg (infusion rate, 80 ml/min). Samples for determination of PCV, plasma volume, blood volume, plasma osmolality, total amount of plasma protein and plasma concentrations of protein, Na, K, and Cl were collected at 0 hour (baseline, before fluid infusion) and 0.5 hour (at the end of fluid infusion), and subsequently, at 0.25- or 0.5-hour intervals for 4.5 hours. All horses were given the predetermined dose of fluids by 0.5 hour after beginning the saline infusion. Values of P less than or equal to 0.05 were considered significant. Administration of hypertonic saline solution was associated with decreased mean body weight by 4.5 hours, but weight change after isotonic saline administration was not significant. Other than body weight and plasma protein concentration, between-trial difference (treatment effect) was not observed for any measured variable or index. The F values indicated that increasing the number of horses would have not changed these results. A time effect was evident across both trials, so that mean (+/- SD) plasma volume increased (12.3 +/- 1.07%) and mean plasma protein concentration (-12.1 +/- 1.03%) and PCV (-11.9 + 0.67%) decreased proportionately and transiently in association with administration of either fluid at that volume. Other time effects included increased plasma osmolality and Na and Cl concentrations. Blood volume estimates and total amount of plasma protein remained unchanged. These data indicate that in conscious clinically normal horses, changes in plasma protein concentration reflect changes in plasma volume and that blood volume may be regulated by alterations in plasma volume and red cell mass. These data also indicate that changes in plasma volume and constituent concentrations may be similar in response to administration of either 0.9% (300 mosm/kg) or 7.2% (2,400 mosm/kg) NaCl solutions (5 ml/kg) and that clinically normal horses can rapidly regulate variable Na loads.

Serum total bile acid concentrations were determined for various types and ages of cattle. There was extreme variability among all the cattle, but the variance was twice as large (0.50 vs 0.22 in logarithmic scale) for beef cattle than for dairy cattle. There was no significant difference in serum total bile acid concentrations between beef cattle and dairy cattle in midlactation. Values for calves < 6 weeks old and for 6-month-old heifers were significantly (P = < 0.05) lower than values for lactating dairy cows. The 5th to 95th percentile range of values (micromol/L) for beef cattle was 9 to 126; for lactating dairy cattle, 15 to 88; and for 6-month-old dairy heifers, 11 to 64.

Porcine blood mononuclear cells (BMC) were exposed to prepartum concentration of estrogen in gilts before acquisition (in vivo), and their subsequent reactivity (in vitro) was explored. In a cross-over experimental designed study, 6 ovariectomized gilts were injected once with 3.75 mg of estradiol-17beta benzoate in arachidic oil or with arachidic oil only during 2 experiments. The ability of their BMC to proliferate in response to stimulation with phytohemagglutinin, concanavalin A, and pokeweed mitogen was assayed in cultures of blood and in cultures of purified BMC. After 2 days of mitogen stimulation, activity of accessible interleukin 2 was quantified in supernatants obtained from cultures of purified BMC and supernatants of blood cultures stimulated with pokeweed mitogen. Also, production of immunoglobulins by purified BMC in response to polyclonal stimuli was measured. Three days after treatment with estradiol, the proliferative response was suppressed in blood cultures stimulated with concanavalin A (P < 0.05) and phytohemagglutinin (P < 0.07). Effects of estradiol treatment were not found in any of the assays performed with purified BMC. We, therefore, assumed that in vivo exposure to estradiol can affect the function of porcine BMC; however, this was only evident when the in vitro assays were performed on blood cultures.

To test the efficacy of a polyvalent Tritrichomonas foetus vaccine, 130 nulliparous heifers were randomly assigned to either receive the test T. foetus vaccine or to serve as nonvaccinated controls. The polyvalent test vaccine consisted of a Campylobacter fetus/Leptospira canicola-grippotyphosa-hardjo-icterohaemorrhagiae-pamona bacterine containing 5 X 10(7) killed T. foetus/dose. The polyvalent control vaccine consisted of the aforementioned formulation without T. foetus. Heifers were administered 2 doses of control or experimental vaccine at 3-week intervals. Heifers were bred to T. foetus-infected bulls and their conception and pregnancy rates were determined throughout gestation. In addition, serum samples were analyzed to determine induced concentrations of antitrichomonal antibodies and vaginal secretions were sampled to determine T. foetus infection rates in control and vaccinated animals. One week after each of the 15-day breeding periods, 60% (6 of 10) of tested vaccinates and 80% (8 of 10) of tested control animals were T. foetus culture-positive. The mean duration of infection of vaccinates was 3.8 weeks (+/- 7.5 days), compared with 5.4 weeks (+/- 7.5 days) of infection for control heifers. All vaccinates developed increased immunofluorescence and serum neutralizing antibody titers following the first immunization, and had additional increases of at least fourfold in response to the second injection. In contrast, no consistent increase in immunofluorescence or serum neutralizing antibodies was observed in control animals. Conception rates were 89.2% for vaccinates and 85.9% for control animals 30 days after breeding and 80 to 90% of these remained pregnant 60 days after breeding. However, within the next 4 months, the pregnancy rate of control heifers decreased to 30% for those that had conceived. During the same 4-month period, more than 60% of vaccinated heifers remained pregnant. Significantly, 62.5% of heifers vaccinated against T. foetus produced calves, whereas only 31.5% of control heifers produced calves. These findings indicate that the polyvalent test vaccine induced an immune response that was effective in lowering the rate of T. foetus infection, decreasing the duration of infection, and reducing losses in calf production attributable to early fetal death and abortion caused by T. foetus infection.

Administration of progesterone in poly(d-,l-lactide) microspheres was used to maintain pregnancy in mares after luteolysis was induced by treatment with pros F2 alpha at day 14 of pregnancy. Mares were given vehicle only (control, n = 6) or 0.75 g (n = 7), 1.5 g (n = 8), or 2.25 g (n = 5) of microencapsulated progesterone at days 12 and 22 of pregnancy. Serum progesterone concentrations were determined daily, and pregnancy was evaluated by transrectal ultrasonography on alternate days. Significantly (P < 0.05) more mares given 1.5 or 2.25 g of progesterone (6 of 8 and 4 of 5 mares, respectively), but not those given 0.75 g (3 of 7 mares), maintained pregnancy through day 32, compared with control mares (O of 6). Progesterone concentrations decreased significantly (P < 0.025) in all groups after administration of prostaglandin F2 alpha at day 14, and significant (P < 0.05) effects of time and treatment on progesterone concentrations were found between days 12 and 22, and 22 and 32. Although treatment with 1.5-g and 2.25-g doses of microencapsulated progesterone improved maintenance of pregnancy, compared with that of vehicle-treated controls, administration of 2.25 g of microencapsulated progesterone appeared to be most efficacious in maintenance of pregnancy during the study interval.

When Salmonella typhimurium and Clostridium perfringens were tested in conventional chickens, larger numbers of S typhimurium and C perfringens adhered to Eimeria tenella-infected ceca than to uninfected ceca. In germ-free chickens, S typhimurium and C perfringens adhered to the E tenella-infected cecal mucosa more than to the uninfected cecal mucosa, but fewer Bacteroides vulgatus and Bifidobacterium thermophilum adhered to the E tenella-infected ceca than to the uninfected ceca. Many bacteria adhered to the lesions caused by E tenella as observed by scanning electron microscopy. On the basis of our findings, we suggest that infection with E tenella upsets the balance of competitive adherence of bacteria, allowing more colonization of S typhimurium and C perfringens.

Affinity chromatography on heparin sepharose was used to identify 2 lipolytic enzymes in heparinized plasma from horses. One enzyme was typical of hepatic triglyceride lipase (HTGL), because it was resistant to inactivation by high concentrations of NaCl, and it did not require the addition of serum for activity. The other enzyme was identified as lipoprotein lipase (LPL), because of its inactivation at NaCl concentrations in excess of 0.2M, and its dependency on addition of serum as a source of apolipoprotein C-II activator. The enzymes were purified by 347- (HTGL) and 442- (LPL) fold, with yields of 54 and 58%, respectively. The partially purified enzymes were used to design incubation conditions that gave optimal activities for each enzyme in vitro. A selective assay was then developed for direct measurement of LPL and HTGL activities in heparinized plasma from horses. Analysis of HTGL took advantage of the almost complete inactivition of LPL when serum cofactor was excluded from the assay at the NaCl concentration that gave optimal HTGL activity. Prior incubation of heparinized plasma with sodium dodecyl sulfate to inhibit HTGL was necessary for measurement of LPL, because HTGL retained 67% of its activity at the NaCl concentration required for optimal LPL activity. Activity of each enzyme was measured in heparinized plasma from 12 Shetland ponies. The mean activity +/- SD for LPL was 3.22 +/- 1.04 micromoles of fatty acids/ml of heparinized plasma/h (micromoles of FA/ml/h). The mean activity for HTGL was 4.9 +/- 1.56 micromoles of FA/ml/h. The performance of the assay was assessed by replicate analysis of pools of each enzyme with high and low activities. The intra-assay coefficient of variation ranged between 3.4 and 8.7% (n = 10), and the interassay coefficient of variation ranged between 5.2 and 10.7% (n = 7) for the same pools analyzed over 7 weeks.