OBJECTIVE To evaluate use of single manual alveolar recruitment maneuvers (ARMs) to eliminate atelectasis during CT of anesthetized foals. ANIMALS 6 neonatal Standardbred foals. PROCEDURES Thoracic CT was performed on spontaneously breathing anesthetized foals positioned in sternal (n = 3) or dorsal (3) recumbency when foals were 24 to 36 hours old (time 1), 4 days old (time 2), 7 days old (time 3), and 10 days old (time 4). The CT images were collected without ARMs (all times) and during ARMs with an internal airway pressure of 10, 20, and 30 cm H2O (times 2 and 3). Quantitative analysis of CT images measured whole lung and regional changes in attenuation or volume with ARMs. RESULTS Increased attenuation and an alveolar pattern were most prominent in the dependent portion of the lungs. Subjectively, ARMs did not eliminate atelectasis; however, they did incrementally reduce attenuation, particularly in the nondependent portion of the lungs. Quantitative differences in lung attenuation attributable to position of foal were not identified. Lung attenuation decreased significantly (times 2 and 3) and lung volume increased significantly (times 2 and 3) after ARMs. Changes in attenuation and volume were most pronounced in the nondependent portion of the lungs and at ARMs of 20 and 30 cm H2O. CONCLUSIONS AND CLINICAL RELEVANCE Manual ARMs did not eliminate atelectasis but reduced attenuation in nondependent portions of the lungs. Positioning of foals in dorsal recumbency for CT may be appropriate when pathological changes in the ventral portion of the lungs are suspected.

Objective-To qualitatively describe lung CT images obtained from sedated healthy equine neonates (≤ 14 days of age), use quantitative analysis of CT images to characterize attenuation and distribution of gas and tissue volumes within the lungs, and identify differences between lung characteristics of foals ≤ 7 days of age and foals > 7 days of age. Animals-10 Standardbred foals between 2.5 and 13 days of age. Procedures-Foals were sedated with butorphanol, midazolam, and propofol and positioned in sternal recumbency for thoracic CT. Image analysis software was used to exclude lung from nonlung structures. Lung attenuation was measured in Hounsfield units (HU) for analysis of whole lung and regional changes in attenuation and lung gas and tissue components. Degree of lung attenuation was classified as follows: hyperinflated or emphysema, −1,000 to −901 HU; well aerated, −900 to −501 HU; poorly aerated, −500 to −101 HU; and nonaerated, > −100 HU. Results-Qualitative evidence of an increase in lung attenuation and patchy alveolar patterns in the ventral lung region were more pronounced in foals ≤ 7 days of age than in older foals. Quantitative analysis revealed that mean +/- SD lung attenuation was greater in foals ≤ 7 days of age (−442 +/- 28 HU) than in foals > 7 days of age (−521 +/- 24 HU). Lung aeration and gas volumes were lower than in other regions ventrally and in the mid lung region caudal to the heart. Conclusions and Clinical Relevance-Identified radiographic patterns and changes in attenuation were most consistent with atelectasis and appeared more severe in foals ≤ 7 days of age than in older neonatal foals. Recognition of these changes may have implications for accurate CT interpretation in sedated neonatal foals with pulmonary disease.

Objective: To investigate contrast-enhanced ultrasonography as a minimally invasive method for the subjective and quantitative assessment of pancreatic and duodenal perfusion in healthy adult dogs, with reference to perfusion in adjacent liver tissue. Animals: 8 clinically normal adult dogs. Procedures: Contrast-enhanced ultrasonograms of the right pancreatic limb, proximal portion of the descending duodenum, and adjacent liver were acquired after IV administration of a microbubble contrast medium. Following subjective evaluation, quantitative time-intensity curves were generated from regions of interest in the pancreas, duodenum, and liver. Five contrast medium characteristics representing perfusion parameters were determined for each organ and used for statistical analysis: interval to arrival, inflow rate, peak intensity (PI), time of peak intensity (TPI), and outflow rate. Results: Significant associations between pancreatic and duodenal values were found for interval to contrast medium arrival, PI, TPI, and outflow rate. Pancreatic and duodenal inflow rates were not correlated. Inflow and outflow rates were significantly faster and TPI significantly shorter for the pancreas and duodenum, compared with values for the liver. There was no significant difference among all 3 organs for interval to arrival and PI of contrast medium. Subjective evaluation findings corresponded to quantitative analysis results. Conclusions and Clinical Relevance: Results suggested that contrast-enhanced ultrasonography may be a useful, minimally invasive method for evaluating pancreatic and duodenal perfusion in dogs. The data from healthy dogs reported here could aid in the assessment of pancreatic and duodenal conditions and their response to medical treatment.

Tissues unsuitable for standard immunohistochemical and histopathological examinations for chronic wasting disease (CWD) in cervids and for scrapie in sheep are frequently submitted for testing. This study investigated the effects of experimental autolysis on the detection of abnormal prion protein (PrPsc) in lymphoid and central nervous system (CNS) tissues from elk and sheep. The PrPsc was detected using a Western blotting (WB) test following PrPsc enrichment using sodium phosphotungstic acid (PTA) precipitation (PTA-WB). A commercial enzyme-linked immunosorbent assay (ELISA) was used as a reference test for quantitative measurement. This study showed that the amount of PrPsc in lymphoid and CNS tssues from elk and sheep decreased gradually as a result of autolysis, but PrPsc was still detectable after 5 and 15 d incubation at 37°C by PTA-WB for all lymphoid and CNS samples. The results of the ELISA supported those of PTA-WB, particularly for CNS tissues. In conclusion, autolysis at 37°C for 15 d would not significantly affect the detection of PrPsc in lymphoid and CNS tissues by WB and ELISA and, particularly, PTA-WB is a valuable and alternative confirmatory test to detect PrPsc in autolyzed lymphoid and CNS samples.

Tissues unsuitable for standard immunohistochemical and histopathological examinations for chronic wasting disease (CWD) in cervids and for scrapie in sheep are frequently submitted for testing. This study investigated the effects of experimental autolysis on the detection of abnormal prion protein (PrPsc) in lymphoid and central nervous system (CNS) tissues from elk and sheep. The PrPsc was detected using a Western blotting (WB) test following PrPsc enrichment using sodium phosphotungstic acid (PTA) precipitation (PTA-WB). A commercial enzyme-linked immunosorbent assay (ELISA) was used as a reference test for quantitative measurement. This study showed that the amount of PrPsc in lymphoid and CNS tssues from elk and sheep decreased gradually as a result of autolysis, but PrPsc was still detectable after 5 and 15 d incubation at 37°C by PTA-WB for all lymphoid and CNS samples. The results of the ELISA supported those of PTA-WB, particularly for CNS tissues. In conclusion, autolysis at 37°C for 15 d would not significantly affect the detection of PrPsc in lymphoid and CNS tissues by WB and ELISA and, particularly, PTA-WB is a valuable and alternative confirmatory test to detect PrPsc in autolyzed lymphoid and CNS samples.

Serum tumor necrosis factor (TNF) activity wasquantitated in 8 horses given an IV infusion of endotoxin (0.03 microgram of lipopolysaccharide/kg of body weight, from Escherichia coli 55:B5) in 0.9% NaCl solution over 1 hour. Serum TNF activity was likewise measured in 6 horses given only 0.9% sterile NaCl solution at the same rate. The duration of serum TNF activity was determined, and serum TNF activity was correlated with clinical and laboratory changes during the induced endotoxemia. Horses had no serum TNF activity prior to endotoxin administration, but geometric mean serum TNF activity was significantly higher from 1 to 4 hours after the start of the infusion. In response to endotoxin, horses seemed depressed, had signs of mild to moderate abdominal pain, developed tachycardia and fever, and had leukopenia followed by leukocytosis. Association between serum TNF activity and temperature, heart rate, attitude abnormality score, and WBC count of horses given endotoxin was significant. Serum TNF activity had a significant positive linear correlation with attitude abnormality and heart rate and a negative linear correlation with the WBC count during endotoxemia. Geometric mean serum TNF activity peaked approximately 1.5 hours prior to mean peak fever, and these data were significantly correlated. Results of this study suggest that TNF is an important mediator of endotoxemia in horses.

Measurements of liver size were made from radiographs of 16 clinically normal anesthetized dogs. Two measurements were made from each of 3 views: right and left lateral and ventrodorsal. Each measurement was correlated with liver weight and volume. Liver weight and volume were also correlated with both measurements from the same radiograph multiplied together. All measurements, with the exception of ventrodorsal depth, correlated significantly (P < 0.05) with liver weight and volume. The multiplication of the 2 measurements made from the right lateral radiograph correlated most highly with liver weight. These data were then compared with those from similar studies involving liver measurements obtained from nuclear scintigraphic and ultrasonographic scans on the same dogs. The radiographic measurements made from the right lateral view had the highest correlation with liver weight, followed by the nuclear scintigraphic measurements made from the same position.

C-reactive protein (CRP) was isolated from equine serum by use of calcium-dependent affinity chromatography conjugated pneumococcal C-polysaccharide, anion exchange chromatography, and gel filtration. It was identified as genuine CRP by its immunochemical cross-reactivity with anti-human CRP, its homology with human CRP in amino acid composition, and its pentameric structure as revealed by electron microscopy. Purified equine CRP had a molecular weight of approximately 118,000 and was composed of 5 identical, nonglycosylated and noncovalently associated subunits with molecular weight of approximately 23,000 each. Equine CRP migrated in the region between beta- and gamma-globulin by results of immunoelectrophoresis, and its isoelectric point was about 7.0. In horses, increased CRP concentration was associated with clinical pneumonitis, enteritis, and arthritis, compared with values obtained in clinically normal horses by use of single radial immunodiffusion method. After IM administration of turpentine oil or castration, serum CRP concentration increased to 6 times higher than baseline values. Results indicate that CRP may be an acute-phase reactant protein in horses.

Immunoturbidimetric determination of serum IgG concentration in foals was compared with the reference methods of single radial immunodiffusion and serum protein electrophoresis. High positive correlations were discovered when the technique was compared with either of these reference methods. The zinc sulfate turbidity test for serum IgG estimation was also evaluated. Although a positive correlation was discovered when the latter method was compared with reference methods, it was not as strong as the correlation between reference methods and the immunoturbidimetric method. The immunoturbidimetric method used in this study is specific and precise for equine serum IgG determination. It is rapid and, thus, is advantageous when timely evaluation of critically ill foals is necessary. The technique should be adaptable to various spectrophotometers and microcomputers for widespread application in veterinary medicine.