Canine circulating neutrophils, isolated by a blood lysing technique, were incubated with 7-S nerve growth factor (NGF), at final concentrations between 12.5 and 800 ng/ml, for 30 minutes at 37 C. Neutrophil cytosolic H2O2 production, measured by flow cytometry, after 7-S NGF incubation was not significantly different from that produced at 37 C (baseline temperature controls) alone. Phorbol myristate acetate (PMA; 100 ng/ml) stimulation of neutrophils produced cytosolic H2O2 concentrations almost 13 times that of baseline temperature control neutrophils. Preincubation of neutrophils with 7-S NGF (100 to 800 ng/ml, 30 minutes, 37 C) and subsequent stimulation by PMA resulted in augmented H2O2 production in excess of twice that of neutrophils treated with PMA alone, and almost 30 times that of baseline temperature controls.

Neutrophils were purified from blood of dexamethasone-treated (0.04 mg/kg of body weight) and untreated calves. Cells were untreated (controls) or cultured in media containing 5 or 10 ng of bovine recombinant granulocyte-macrophage colony-stimulating factor (rbGM-CSF)/ ml for 10 to 12 hours before being tested for various functions. Dexamethasone treatment of calves decreased luminol-dependent chemiluminescence, decreased phagocytosis of Pasteurella multocida and several Staphylococcus spp by various degrees, and decreased antibody-dependent cell-mediated cytotoxocity against bovine herpesvirus-infected cells by 26 to 32%. The percentage phagocytosis of coagulase-positive S aureus and S intermedius was higher than that of coagulase-negative S epidermidis for neutrophils from all calves. Culture of neutrophils with rbGM-CSF significantly increased (P < 0.05) all of the aforementioned functions, compared with control neutrophils; however, rbGM-CSF-induced increases in function tended to be higher in neutrophils from dexamethasone-treated calves than in neutrophils from untreated calves.

Logistic regression was used to develop models predicting preweaning survival in 334 neonatal swine. Measured risk factors included birth weight, litter size (live born), dam parity, serum IgG concentration, serum ELISA titers recognizing common gram-negative core antigens, and serum concentrations of the third component of complement. Larger birth weights were associated with increased probability of preweaning survival. The highest mortality was observed in litters with more than 12 pigs. Pigs with serum concentration of the third component of complement (C3) in the lowest stratum, < 20% adult pooled C3 standard (APC3), had reduced mortality, compared with high (> 38% APC3) and middle (20 to 38% APC3) groups. Associations between all other variables, including total serum IgG concentration and preweaning survival were not significant. Few pigs had hypogammaglobulinemia, < 3% of the study population had serum IgG concentrations < 1 g/dl. Of all measured variables, only birth weight and dam parity were significant predictors of preweaning gain. Larger pigs and pigs born to third or greater parity dams had more preweaning gain than other pigs.

Important procedural factors in the under-agarose assay for porcine neutrophil migration were identified, and optimal conditions were established. Three factors were tested: the concentration of zymosan-activated serum inoculated into the outer well; the number of neutrophils inoculated into the center well; and the time of incubation of the agarose plates. All factors had a significant (P < 0.0001, 0.0001, and 0.01, respectively) effect on the chemotactic index of porcine neutrophils. The optimal combination of these 3 factors was undiluted zymosan-activated serum as the chemoattractant, 8 x 10(5) neutrophils inoculated into the center well, and 5 hours of incubation. The assay was validated, using standard conditions, and the data were used to predict the number of pigs and/or repetitive assays needed to identify differences among experimental groups.

Colony hybridizations with DNA probes for 3 heat-stable (STaP, STaH, and STb) enterotoxins and 1 heat-labile (LT) enterotoxin and for 4 adhesins (K99, F41, K88, 987P) were performed on 870 Escherichia coli isolates to determine pathotypes prevalent among enterotoxigenic E coli (ETEC) isolated from cattle in Belgium. One hundred thirty-two E coli isolates (15.2%) hybridized with probes STaP, K99, and/or F41. The 5 other probes were not hybridized by E coli isolates. Therefore, only STaP enterotoxin and K99 and F41 adhesins were virulence factors of ETEC isolated from cattle. Two major pathotypes accounted for 95% of the ETEC: STaP+K99+F41+ (67.4%) and STaP+K99+ (27.3%). The last 5% of probe-positive isolates had STaP+, STaP+F41+, or K99+F41+ minor pathotypes. Of 12 American ETEC isolates also assayed, 7 were positive with STb and/or 987P probes (pathotypes STaP+STb+,STaP+ 987P+, or STaP+STb+987P+) and may be porcine- rather than bovine-specific enteropathogens. The remaining 5 American ETEC isolates belonged to 3 minor pathotypes (STaP+,STaP+F41+, and K99+F41+) also found among Belgian E coli isolates. Such isolates may be derivatives of STaP+K99+F41+ or STaP+K99+ ETEC after in vivo or in vitro loss of virulence genes and/or non-ETEC isolates, which have acquired virulence genes by in vivo transfer.

Cows naturally infected with Brucella abortus developed antibody (Ab) responses to a nonlipopolysaccharide antigen (NLA) purified from B abortus strain 1119-3. Sera from strain 19-vaccinated cows did not have detectable amounts of Ab. Weak lymphoproliferative responses to NLA were observed in blood mononuclear cell suspensions obtained from infected cows. There was no evidence of NLA-specific lymphoproliferation in cell suspensions from healthy cows. Nonlipopolysaccharide antigen binding to bovine blood mononuclear cells was observed by antigen-consumption assays and direct binding of radiolabeled antigen. Cells from infected cows bound less NLA than did cells from healthy cows when assays were conducted with intact blood mononuclear cell preparations (monocytes plus lymphocytes). Monocytes obtained from any group did not bind NLA. Purified B lymphocytes from infected and healthy vaccinated cows bound about 3 times more NLA than did T lymphocytes, but there were no apparent differences between the 2 groups in extent of binding. Results of the study indicate that bovine lymphocytes have binding sites for a NLA purified from B abortus strain 1119-3.

Articular cartilage specimens from the distal articular surface of 32 radiocarpal bones from 24 2- to 5-year-old horses were analyzed. The total collagen content was determined on the basis of the 4-hydroxyproline content, using a colorimetric method. A method for estimating the proportions of types-I and -II collagen by measuringspectrophotometric densities of specific cyanogen bromide peptide bands from mixtures of types-I and -II collagen on sodium dodecyl sulfate-polyacrylamide gels was used. The cyanogen bromide peptides representative of each collagen types-I and -II were identified. The peptide ratios were then computed for each of several standards of type-I and -II mixtures. A standard curve was derived from the correlation between these ratios and the corresponding proportions of type-II collagen in standard mixtures. Galactosamine and glucosamine content (hexosamines) were measured by ion chromatography. Thegalactosamine-to-glucosamine ratio, chondroitin sulfate and keratan sulfate values, and total glycosaminoglycan content were derived from the measured hexosamine content. The total collagen content averaged 556 mg/g (55.6 mg/100 mg) of tissue (dry weight, [dw]). Type-II collagen was the major collagen type in normal articular cartilage specimens. The ratio of the area under the alpha 1 (II)CB10 peak to the area under the alpha 1 (I)CB 7,8 + alpha 1 (II)CB11 peak was a second-order polynomial function of the proportion of type-II collagen in the specimens. The mean galactosamine and glucosamine content were 20.6 mg/g and 7.9 mg/g (dw), respectively. The meangalactosamine-to-glucosamine ratio was 3.74 +/- 0.62. Chondroitin sulfate values, keratan sulfate values, and total glycosaminoglycan content were 53.3 +/- 4.9 mg/g, 19.9 +/- 3.6 mg/g, and 73.2 +/- 7.9 mg/g (dw), respectively. There was no significant correlation between the age of the horses and any of the chemical values (P>0.1). The biochemical composition of articular cartilage in the horse is similar to that of other species.

Atracurium besylate, a nondepolarizing neuromuscular blocking agent, was administered as an infusion to 8 anesthetized cats in which neuromuscular blockade was assessed, using the train-of-four response. Once 50% depression of the first-twitch (T1) response was achieved, the infusion was held constant for 60 minutes before being discontinued and the recovery time was determined. The time for recovery was recorded as the time for the train-of-four ratio (T4 ratio) to increase from 50% to 75%. After recovery, atracurium infusion was reinstituted and the cats were again maintained for 60 minutes at 50% depression. A single bolus of gentamicin sulfate (2.0 mg/kg of body weight) was administered IV, and the infusion was continued for another 60 minutes before it was discontinued and the time for recovery was recorded. Within 1 minute of gentamicin administration, the mean +/= SD T1 response decreased from 49 +/- 5% to 33 +/- 8% of baseline and the T4 ratio decreased from 28 +/- 19% to 14 +/- 11%. Peak effect occurred at 5 minutes, with a T1 response of 29 +/- 6% of baseline and a T4 ratio of 13 +/- 12%. By 60 minutes after gentamicin administration, the T1 response had increased to 38 +/- 7% of baseline and the T4 ratio had increased to 21 +/- 13%. The time for recovery significantly (P less than 0.03) increased from 9.9 +/- 3.4 minutes during the control study to 18.1 +/- 10.7 minutes during the gentamicin study. In this study, gentamicin potentiated the neuromuscular blockade induced by atracurium and increased the recovery time. Residual blockade, observed after gentamicin administration was reversed with edrophonium.

Perfusion and viability of island axial pattern skinflaps were tested in 37 healthy New Zealand white rabbits, using laser Doppler monitoring of blood flow in the capillary loops and the subpapillary plexus of the dermis. Skin flaps, selected on the basis of the caudal superficial epigastric vein and artery, were lifted and replaced in their original locus after selective occlusion of their vascular pedicles. Subjects were allotted into groups: control group (n = 10); arterial occlusion (n = 7); venous occlusion (n = 10); and arterial and venous occlusion (n = 10). The rabbits were monitored from 48 hours before surgery until euthanasia 48 to 72 hours after replacement of the flap. Flap viability was assessed on a clinical basis, using a comparative scoring method based on a numeric scale. The degree of necrosis in histologic sections was evaluated, using a scoring system. Laser Doppler measurements were obtained on 3 consecutive days before surgery, to establish the normal basal blood flow in the skin. Postsurgical measurements were obtained at 2-hour intervals for the first 8 hours and at 24, 48, and 72 hours after surgery. Measurements of basal blood flow varied significantly (P < 0.05) from site to site on the surface of individual flaps and over time. When laser Doppler flowmetric (LDF) measurements from 6 sites on a flap were used as a measure of laser Doppler flow for the total flap, there was no significant difference between contralateral flap areas outlined on the abdomen of the rabbits. Temporal variations over 3 days for each rabbit or among rabbits were not significant. The LDF measurements detected acute vascular occlusion when compared with the controls, and were able to differentiate between control and arterial occlusion groups, control and venous occlusion groups, control and arterial and venous occlusion groups, arterial and venous occlusion groups, venous and arterial and venous occlusion groups (P < 0.05), but not between arterial and arterial and venous occlusion groups. Evaluation of LDF values at 4 hours proved to be a better predictor than clinical assessment at 4 or 8 hours in evaluating skin flap viability.

A method of inducing Pasteurella haemolytica serotype 1 (Ph1) lung infection in goats, using low numbers of bacteria and without impairing host immunity, was developed. Two trials were conducted. Results of trial 1, using 10 principals (Ph1 agar beads) and 6 controls (agar beads alone), indicated that Ph1 organisms imbedded in agar beads could survive host lung defenses for 32 days. Results of trial 2 indicated that lung immunity in the inoculated goats (principals) was high and they were more protected than controls against a transthoracic challenge of Ph1 (1.18 X 10(7) colony-forming units) injected into lung of each goat on posttreatment day 35. When comparing challenge-exposed principals with controls, the controls developed rectal temperatures above normal for a longer time, duration of anorexia was longer, and sign of depression were seen. The controls developed large are of consolidated lung tissue, more Ph1 isolates were recovered from nasal turbinates and lung tissue, and higher Ph1 concentrations were found in the lungs. The serum Ph1 indirect hemagglutination antibody titers in the principals of both trials increased, compared with titer in controls. Principal goats in trial 2 had higher Ph1 indirect hemagglutination antibody titers after injection of Ph1-impregnated agar beads and less severe lung lesion after challenge exposure than did controls. The small pneumonic consolidated lesions in the principals, compared with extensive lesions in controls after Ph1 challenge exposure, indicated a high degree of immunity after exposure to Ph1 organisms imbedded in agar beads.