Isolated segments of left dorsal colon and a side-to-side colocolostomy (between the left ventral colon and left dorsal colon) were surgically created in 6 adult ponies. Four segments, each separated by an empty segment, were inoculated (20 ml) with 1 of the following 4 solutions: phosphate buffered saline solution (PBSS)/1% polyethylene glycol (PEG); purified cholera toxin in PBSS/1% PEG (5 micrograms cholera toxin/ml of PBSS/1% PEG); lyophilized Salmonella typhimurium UCD 1755 culture lysate, reconstituted in PBSS/1% PEG; and viable S typhimurium UCD 1755 (10(8) organisms/ml of PBSS/1% PEG). Twenty hours following inoculation of the treatment solutions into the isolated colon segments, the ponies were reanesthetized. Fluid accumulation in the isolated segments was measured, and tissue samples from isolated segments were taken for examination by light microscopy and electron microscopy, and for measurement of mucosal cyclic adenosine monophosphate levels. There was fluid accumulation in segments inoculated with cholera toxin in 4 ponies (29.5 +/- 12.7 ml), and in segments inoculated with S typhimurium UCD 1755 culture lysate in 3 ponies. (14.0 +/- 8.7 ml). There was no fluid accumulation in segments inoculated with either the control solution (PBSS/1% PEG) or viable S typhimurium UCD 1755. There was significantly (P less than 0.05) less cyclic adenosine monophosphate in segments inoculated with cholera toxin, Salmonella lysate, and viable Salmonella, compared with control segments. Histologically, there were minimal changes in control segments, consisting of mild to moderate submucosal edema and capillary congestion. Changes in the other segments were more pronounced and included neutrophilic infiltration and exocytosis, with the changes increasing in severity in the segments inoculated with cholera toxin, S typhimurium culture lysate UCD 1755, and viable S typhimurium UCD 1755, respectively. Ultrastructurally, mucosa from control segments was normal. Mucosa from segments inoculated with cholera toxin had swollen endoplasmic reticula and basolateral separation of surface epithelial cells. Mucosa from segments inoculated with S typhimurium UCD 1755 culture lysate and viable S typhimurium UCD 1755 had swollen smooth and rough endoplasmic reticula, separation of epithelial cells, degeneration of microvilli, and goblet cell degeneration.

The virulence of 2 porcine group-A rotavirus isolates was compared. Forty hysterotomy-derived 3-day-old gnotobiotic pigs were inoculated orally with 2 ml of intestinal homogenate containing either the Ohio State University (OSU) or the South Dakota State University (SDSU) strain of porcine rotavirus or were inoculated with medium only. Clinical signs of disease, body weight, distribution of viral antigen, fecal excretion of virus, and histologic lesions (observed by light and scanning electron microscopy) were determined. Morphometric measurements of villi and crypts were made. In pigs inoculated with OSU or SDSU strains, diarrhea began at postinoculation hours (PIH) 19 to 48 and PIH 24 to 54, respectively. None of the virus-infected pigs died as a consequence of infection and all had similar clinical signs of disease, body weight changes and virus-shedding patterns, regardless of the strain of rotavirus with which they were infected. Microscopic findings in the small intestine of virus-infected pigs were similar, except that the SDSU strain caused more severe villus atrophy and villus fusion in the duodenum at PIH 72 and 168 than was associated with the OSU strain. Viral antigen in the small intestine of pigs infected with either virus was observed by use of immunofluorescence at PIH 24 and 72, but was seldom seen at PIH 168.

Natural killer (NK) cell activity and function were determined for 11 untreated and treated dogs with lymphoma. Concurrent chromium release and single cell binding assays, methods used to measure overall cytotoxic activity and that from individual cells, respectively, were performed at effector-to-target cell ratios of 50:1 and 100:1, with incubation periods of 12 and 16 hours. Significant reduction was achieved in overall activity for untreated dogs, using a 16-hour incubation period and an effector-to-target ratio of 100:1 (P less than 0.05). Decreased activity (P less than 0.025) was also achieved for those dogs that were administered combination chemotherapy, consisting of such drugs cyclophosphamide, vincristine, prednisone, and doxorubicin. There was no significant difference in binding or cytotoxin activity by individual cells in the untreated or treated dogs, compared with the healthy controls. Short- or long-term treatment with glucocorticoids did not influence overall NK cell activity or individual cell cytotoxicity. The overall cytotoxic activity in untreated dogs was reduced, but these dogs had relatively normal numbers of NK cells compared with paracontrols. This suggests that a defect in recycling, or the ability to kill targets repetitively, may be involved. A similar defect was found in NK cells of dogs treated aggressively with combination chemotherapy.

Serum immunoglobulins of the IgG isotype recognizing common gram-negative cell core epitopes were serially measured by use of a direct ELISA on blood obtained from 10 neonatal swine. An R-mutant Escherichia coli (strain J5) was used as a plate antigen. Total serum IgG was measured by use of radial immunodiffusion. Half-lives of core antigen-specific IgG (6.81 days) and total serum IgG (14.85 days) were dramatically different (P less than 0.01).

Ovariectomized, nonlactating cows were treated with IM injections of either physiologic saline solution or prostaglandin F2 alpha. Plasma concentrations of cortisol increased significantly by 30 to 60 minutes after injection of prostaglandin F2 alpha, but there were no significant increases in plasma concentrations of estradiol, progesterone, or testosterone. After saline solution treatment, there were no increases in any of the hormones measured.

Thirty mares with normal estrous cycles were allotted equally to 5 groups and infused with 250 ml of saline (NaCl) solution in utero on the seventh day after ovulation to test the effects of temperature, osmolarity, or pH of the saline solution on prostaglandin F2 alpha (PGF2 alpha) release and luteolysis. Intrauterine infusion of phosphate-buffered saline solution failed to alter the duration of the luteal phase, compared with the control group. Similarly, increasing the temperature of phosphate-buffered saline solution to 42 C or increasing (600 mosm) or decreasing osmolarity (less than 10 mosm) did not change the duration of the luteal phase. Decreasing the pH of saline solution to 3 caused significant (P less than 0.0001) re leases of PGF2 alpha from the uterus within the first hour after infusion, and the luteal phase was shortened to 8.8 +/- 1.0 days (mean +/- SEM; control, 15 +/- 1.2 days). The results of this study showed that pH is main factor in eliciting PGF2 alpha release by intrauterine infusion of a saline solution, whereas increased temperature and osmolarity have no effect on the release of PGF2 alpha. The intrauterine infusion of sterile water or physiologic saline (NaCl) solution has been used to induce estrus in mares for the past 50 years. Many investigators 1-10 have reported that intrauterine infusion of physiologic saline solution or water at body temperature (37 C or warmer up to 45 C) causes most "anestrous" mares to return to estrus in 1 to 8 days. The mare's ability to respond to intrauterine infusion was further defined when Arthur 11,12 demonstrated that estrus could be initiated only in mares in middiestrus or in pseudopregnancy, and Ginther and Meckley 13 reported intrauterine infusion was effective only during days 5 to 9 of diestrus. We subsequently demonstrated that the effect of intrauterine infusion of saline solution involved shortening the luteal phase.

Serum protein electrophoresis was performed on 71 clinically healthy juvenile and adult llamas (6 juvenile males, 7 juvenile females 25 adult males, 13 adult females, and 20 pregnant females) to determine normal serum protein concentrations. Values were reported for each of the 5 groups because the groups were not homogeneous in all 8 peaks. Although the values reported here may serve as reference values for adults, they represent only a guideline for the juveniles because of the limited number of animals in each of these groups.

The 51Cr-labeled EDTA was validated as a suitable permeability probe in dogs for measurement of passive, unmediated diffusion across intestinal mucosa via intercellular pathways. The 51Cr-labeled EDTA was stable in aqueous solution and did not bind to biologic tissue and fluids. After incubation of 51Cr-labeled EDTA in isolated jejunal loops, analytic subcellular fractionation of jejunal mucosa on reorientating sucrose-density gradients was performed, and no association of 51Cr-labeled EDTA with particulate intracellular organelles was detected. Intravenously administered 51Cr-labeled EDTA was rapidly and completely excreted in urine. Intestinal permeability to 51Cr-labeled EDTA after oral administration was assessed in healthy dogs. The percentage of the administered dose of 51Cr-labeled EDTA excreted in the urine in 24 hours ranged from 2.3 to 17.6% (median, 13%).

Serum biochemical indicators of liver function were determined in healthy, age-matched foals during the first 270 days of life. Values were compared with those of healthy adult horses and with those determined on the day of birth (< 12 hours old). Serum alkaline phosphatase, gamma-glutamyl transferase, and L-iditol dehydrogenase activities were increased during the first 2 weeks of life. Serum cholesterol, triglyceride, and total and unconjugated bilirubin concentrations peaked during this same period. During the early neonatal period (<12 hours old), globulin concentrations (mainly beta 2 and gamma fractions) were low and albumin/globulin ratios were high. However, individual values for all analytes were varied.

Experimental intranasal inoculation of cattle with Pasteurella haemolytica serotype 1 resulted in a group that shed the bacteria in their nasal secretions (colonized) and a group that did not shed (uncolonized). After inoculation, antibody titers in serum and nasal secretions against the total P haemolytica increased significantly, and the proportion of total antibody against specific P haemolytica antigens changed so that the proportion directed against the 94- and 62-kD antigens increased. Prior to inoculation, the proportion of total antibody in the serum against 94- and 62-kD antigens of P haemolytica was higher in calves that remained uncolonized than in those that became colonized with P haemolytica after exposure. Antibody specificity of serum and nasal secretions differed in the relative amounts directed against each P haemolytica antigen. The specificity against P haemolytica antigens differed between IgG and IgA isotypes of serum and nasal secretions, with IgA being directed against fewer antigens than was IgG.