The functional characteristics of polymorphonuclear leukocytes (PMN), considered to be the first line of host defense against infections, from rhesus macaques confirmed to have simian retrovirus (SRV)-induced simian acquired immunodeficiency syndrome (SAIDS), were evaluated. The PMN from SRV antibody-positive macaques without clinical signs were chemotactically responsive. Their phagocytic and killing capabilities were normal, and their cell membranes were highly deformable. However, PMN from SRV antibody-positive macaques and with persistent lymphadenopathy, as well as having at least 3 of the 11 common clinical signs of SAIDS, were chemotactically nonresponsive. Their phagocytic and killing capabilities were compromised, and their cell membranes were rigid and nondeformable. In general, PMN from macaques with clinically confirmed SAIDS were functionally deficient. The results are similar to those obtained in other retroviral infections and can be clinically significant, because the host defense deficiency may be responsible for the recurrent and opportunistic infections in SAIDS.

Acidemia stimulates renal ammonia production and excretion. This adaptive response allows increased H+ secretion and generation of new bicarbonate. To determine whether a relationship existed between urine ammonium (NH4+) concentration and excretion and urine anion gap (Na+ + K+ - Cl-), ammonium chloride (NH4Cl) was administered per OS for 5 days to induce systemic acidemia in 12 healthy Beagles. During NH4Cl administration, a strong, statistically significant (P < 0.0001) relationship was apparent between urine NH4+ concentration measured in millimoles per liter and urine anion gap. Regression equation: urine [NH4+] = 8.2 - 0.416 X urine anion gap; r = -0.897. A statistically significant (P = 0.0001) relationship existed between urine NH4+ excretion measured in millimoles per kilogram of body weight per day and urine anion gap. Regression equation: urine NH4+ excretion = 0.74 - 0.38 X urine anion gap; r = -0.768. As urine NH4+ concentration or excretion increased, urine anion gap became more negative. Before NH4Cl administration (no systemic acidemia), a weak, but statistically significant (P = 0.015) relationship was observed between urine NH4+ concentration and urine anion gap. Regression equation: urine [NH4+] = 65.2 - 0.141 X urine anion gap; r = -0.41. However, a relationship was not evident between urine NH4+ excretion and urine anion gap before NH4Cl administration. Hence, urine anion gap is a reliable index of urine NH4+ concentration and excretion only in dogs with metabolic acidosis. In human beings with distal renal tubular acidosis, NH4+ excretion is inappropriately low and results in a positive urine anion gap. Therefore, as a reliable index of NH4+ excretion, urine anion gap may represent an easy and rapid method to aid in the diagnosis of distal renal tubular acidosis in dogs.

A new topically administered anhydrase inhibitor, MK-927, evaluated for its ocular hypotensive activity in normotensive and glaucomatous Beagles. Single- and multiple-dose studies were performed. Six concentrations of the drug were evaluated in the single-dose study and the 2% solution was used for multiple-dose evaluation. The decrease in intraocular pressure (IOP) was greater in glaucomatous Beagles at the higher concentrations of the drug. The 2 and 4% solutions of MK-927 significantly lowered IOP (mean, 5 mm of Hg; SEM +/- 1.6 and SEM +/- 1.2, respectively) in normotensive and glaucomatous Beagles. In the multiple-dose study, IOP was significantly decreased in the normotensive (mean, 4 mm of Hg; SEM +/- 0.74) and glaucomatous Beagles (mean, 9 mm of Hg; SEM +/- 1.2). The maximal effect was observed by day 4. A contralateral effect was found in glaucomatous Beagles, with the maximal effect on day 4.

To study the antibody response to glycoprotein I (gI) of pseudorabies virus (PRV) in maternally immune pigs, 3 groups of 6 pigs were given low doses of the mildly virulent Sterksel strain of PRV at 3 and 11 weeks of age. Group A consisted of seronegative pigs; groups B and C consisted of pigs with maternal antibodies deficient of antibodies to gI. At 3 weeks of age, 3 pigs of each group were inoculated intranasally with 10(2.5) plaque-forming units (groups A and B), or with 10(3.5) plaque-forming units (group C) of PRV. The 3 other pigs in each group were contact-exposed to the inoculated pigs. In group A, 4 of 6 pigs shed virus and all developed antibodies to gI of PRV and produced PRV-specific IgM and virus-neutralizing antibodies. In groups B and C, 10 pigs shed virus and all developed low and inconsistent titers of gI antibodies, whereas only 3 pigs produced PRV-IgM antibodies with low titers. Thus, after PRV infection of pigs with high concentrations of maternal antibodies deficient of gI antibodies, the antibody responses to PRV were severely inhibited. The pigs were reinoculated with 10(3) plaque-forming units of the same virus 8 weeks after the first inoculation. The pigs in group A did not respond at all, as they were immune. The pigs in groups B and C shed considerable amounts of virus. Three pigs had a clear secondary antibody response to gI, whereas the others developed an early to normal antibody response to gI. None of the pigs mounted a secondary neutralizing antibody response to PRV. We concluded that inoculation of pigs having high titers of gI-deficient maternal antibodies with low doses of a mildly virulent PRV, induced low to undetectable concentrations of antibodies to gI.

The effects of intra-articular administration of dimethylsulfoxide (DMSO) on chemically induced synovitis in the middle carpal joint of 6 weanling horses were evaluated. Following aseptic collection of synovial fluid, the middle carpal joint of each forelimb was injected with 50 mg of Na-monoiodoacetate to induce synovitis. Eight days after injection, synovial fluid was obtained and the right middle carpal joints were injected with 2 ml of 40% DMSO in lactated Ringer solution. The corresponding joints of the left limb (control) were injected with 2 ml of lactated Ringer solution. Sampling and treatments were repeated on post-injection days 11 and 14, for a total of 3 treatments. Horses were visually evaluated daily for lameness and joint effusion. Synovial fluid was evaluated for color and clarity, differential and total WBC count, total protein content, and hyaluronic acid concentration. The Kaegi gait analysis system provided an objective assessment of lameness prior to inducing synovitis, again on day 7, and on day 17. At necropsy (day 17), synovial fluid, synovial membrane, and articular cartilage specimens were collected. Joint effusion was evident 12 hours after injection ofNa-monoiodoacetate in all joints. Mild lameness was evident at 24 hours; however, the lameness resolved by 72 hours. Objective assessment of lameness did not reveal significant differences between treatment or control limbs. Hyaluronic acid concentrations increased significantly (P = 0.023) above baseline values in most joints over the study period. Synovial fluid WBC counts increased significantly (P = 0.002) following Na-monoiodoacetate injection and remained significantly (P = 0.002) above baseline values throughout the study. There was a significantly greater decrease (P = 0.04) in total WBC counts between the pretreatment and final sampling period in the DMSO-treated joints, compared with the controls. Histologic evaluation of synovial membrane samples revealed a significantly less inflammatory response in 4 of 6 DMSO-treated joints, compared with that in the controls. Histochemical staining of articular cartilage did not reveal any observable difference between treated or control specimens.

An indexing system for hygiene variables associated with egg production was developed by use of datacollected from chicken flocks in southern California. The data were analyzed by factor and regression analysis. On the basis of our findings, hygiene index in relation to egg production consists of ventilation system, cooling system, manure removal, and truck movement. Flocks kept under natural ventilation produced, on the average, 2% more hen-day eggs than flocks kept under artificial ventilation. Flocks placed in houses with roof sprinklers produced 3.3% more hen-day eggs, compared with flocks placed in houses with inside foggers and pad. Flocks kept under the system of frequent removal of manure produced 2% more hen-day eggs than flocks kept under the system for which the manure was removed less frequently. Flocks kept in farms that restricted trucks collecting dead birds from entering the premises produced 3.4% more hen-day eggs than those that allowed such trucks to enter the farm.