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Abstract

Objective—To evaluate the activity of Kupffer cells (KC) of control neonatal pigs and neonatal pigs treated with endotoxin and to compare activity of KC with that of pulmonary alveolar macrophages (PAM).

Sample Population—Kupffer cells and PAM obtained from 24 neonatal pigs (7 to 10 days old).

Procedure—Pairs (n = 7) of littermates served as treated (lipopolysaccharide [LPS]) or untreated pigs. Pigs were euthanatized 24 hours after treatment, and cells were isolated. Cells were obtained from 10 other neonatal pigs for other assays. Functional activity of cells was evaluated by use of in vitro assays to evaluate bactericidal activity, phagocytosis, and production of superoxide anion (SOA), nitric oxide (NO), and tumor necrosis factor-α (TNF-α). Each assay was repeated on cells obtained from 4 to 6 pigs.

Results—Phagocytic activity was similar in KC and PAM, but bactericidal activity and production of SOA and TNF-α was lower in KC. Neither KC nor PAM produced NO in response to LPS stimulation. Phagocytosis, bactericidal activity, and production of SOA were enhanced for KC obtained from neonatal pigs treated with LPS. The PAM from LPS-treated neonatal pigs had similar bactericidal activity to PAM obtained from untreated pigs.

Conclusions and Clinical Relevance—Functional capacity of KC is affected by endotoxin. This provides additional information of the role the liver plays in immune surveillance. In addition, the response of KC in neonatal pigs exposed to endotoxin is of value for understanding gram-negative bacterial sepsis, which is a major cause of mortality in neonatal pigs. (Am J Vet Res 2001;62:1040–1045)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effect of homologous amniotic fluid and meconium inoculated intratracheally into the lungs of neonatal rats.

Animals—153 male 7-day-old Fischer-344 rats.

Procedure—Amniotic fluid was obtained by cesarean section from the uterus of pregnant rats and meconium was collected at the time of birth from the gastrointestinal tract of neonatal rats. Neonatal rats were randomly allocated into 5 treatment groups. Two groups received 0.05 ml of saline (0.9% NaCl) solution; the third and fourth groups received 0.05 ml of 50% or 100% amniotic fluid, respectively; the fifth group was inoculated with 0.05 ml of a 20% suspension of meconium. Six or 7 rat pups/group were euthanatized by exsanguination under halothane anesthesia at postinoculation days 1, 3, 7, and 14. The magnitude of injury and inflammatory response was determined by biochemical and cytologic analyses of bronchoalveolar lavage fluid.

Results—Inoculation with saline solution and amniotic fluid did not induce pulmonary injury or inflammatory response. Inoculation with meconium induced significant ( P < 0.01) injury and inflammatory response, characterized by the release of cytosolic enzymes and recruitment of neutrophils in the lung.

Conclusion and Clinical Relevance—Saline solution is an innocuous vehicle that can be safely used in intratracheal inoculations in neonatal rats. Homologous amniotic fluid, despite containing keratin and epidermal cells, does not cause acute injury or inflammation in the lung. In contrast, meconium acts as a toxic substance injuring respiratory cells and causing a vigorous but transient leukocytic inflammatory reaction in the lungs. (Am J Vet Res 2001;62:1636–1641)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether passive transfer of IgG in neonatal kittens affects plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses to bacteria in vitro.

Animals—22 kittens from 6 specific pathogen-free queens.

Procedure—Kittens were randomized at birth into the following treatment groups: colostrum-fed, colostrum-deprived, or colostrum-deprived supplemented with feline or equine IgG. Blood samples were collected at intervals from birth to 56 days of age. Plasma IgG concentrations were determined by radial immunodiffusion assay. Neutrophil function was assessed by a flow cytometry assay providing simultaneous measurement of bacteria-induced phagocytosis and oxidative burst. The opsonic capacity of kitten plasma was determined in an opsonophagocytosis assay with bacteria incubated in untreated or heat-inactivated plasma.

Results—Among treatment groups, there were no significant differences in neutrophil phagocytic and oxidative burst responses to bacteria or opsonic capacity of plasma. In all samples of plasma, inactivation of complement and other heat-labile opsonins significantly reduced the opsonic capacity. Plasma IgG concentrations in kittens did not correlate with neutrophil function or plasma opsonic capacity before or after inactivation of complement.

Conclusions and Clinical Relevance—The plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses in vitro of kittens receiving passive transfer of IgG via colostrum intake or IgG supplementation and those deprived of colostrum were similar. The alternate complement pathway or other heat-labile opsonins may be more important than IgG in bacterial opsonization and phagocytosis. ( Am J Vet Res 2003;64:538–543)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To characterize intragastric pH profiles in critically ill foals and determine whether administration of ranitidine altered pH profiles.

Design—Prospective observational study.

Animals—23 hospitalized neonatal foals ≤ 4 days of age.

Procedure—Intragastric pH was measured continuously for up to 24 hours by use of an indwelling electrode and continuous data recording system. In 21 foals, ranitidine was administered IV.

Results—10 foals had predominantly or exclusively alkaline profiles, 10 had profiles typical of those reported for healthy foals, with periods of acidity (hourly mean pH < 5.0 at least once), and 3 had atypical profiles with periods of acidity. All 10 foals that had intragastric pH profiles typical of healthy foals survived, whereas only 2 foals with alkaline profiles survived, and none of the foals with atypical profiles survived. The effects of ranitidine administration could not be assessed in 13 foals because of a high baseline intragastric pH. In 7 of the remaining 9, ranitidine administration resulted in an alkalinizing response, but this response was often of blunted duration. Ranitidine administration did not appear to alter the intragastric pH profile in the remaining 2 foals.

Conclusions and Clinical Relevance—Results suggested that hospitalized critically ill foals often have intragastric pH profiles different from those reported for healthy foals and may respond differently to ranitidine administration than do healthy foals. Many critically ill foals have continuously alkaline intragastric pH profiles, questioning the need for prophylactic administration of ranitidine in all critically ill foals. (J Am Vet Med Assoc 2001;218:907–911)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the efficacy of Lactobacillus pentosus WE7, an equine-origin organism with potentially beneficial in vitro properties, as a probiotic for prevention of neonatal diarrhea in foals.

Design—Randomized controlled clinical trial.

Animals—153 foals.

Procedure—Foals were enrolled at 24 to 48 hours of age and randomly assigned to treatment or control groups. The treatment group received approximately 2 × 1011 CFU of freeze-dried L pentosus WE7 orally once daily for 7 days, whereas the control group received a placebo. Clinical monitoring was performed for 14 days.

Results—Probiotic administration was significantly associated with development of signs of depression, anorexia, and colic and the need for veterinary examination and treatment. Probiotic-treated foals also had more days of diarrhea, compared with the control group, although not significantly. In a multivariate model, probiotic administration was significantly associated with development of diarrhea and diarrhea plus additional clinical abnormalities.

Conclusions and Clinical Relevance—Administration of L pentosus WE7 did not prevent diarrhea; rather, it was associated with development of diarrhea and, most importantly, development of diarrhea plus additional clinical abnormalities and the need for veterinary intervention. The promising in vitro properties of L pentosus WE7 were not evident in vivo. Results raise concern about the variety of untested probiotic products that are commercially available. Safety and efficacy testing needs to be performed for all potential equine probiotics. (J Am Vet Med Assoc 2005;226: 2031–2034)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess data regarding clinical features, clinicopathologic and blood gas variables, and outcome from horse and mule foals with confirmed neonatal isoerythrolysis (NI).

Design—Retrospective case series.

Animals—17 horse and 1 mule foals.

Procedure—Medical records of foals (< 14 days old) with NI were reviewed. Information collected included signalment; clinical examination findings; results of hematologic, serum and plasma biochemical, and venous blood gas analyses and urinalysis; treatments; and outcome.

Results—Data from 17 horse foals and 1 mule foal with NI (mean age, 71 hours) were evaluated. Many foals had high serum indirect and direct bilirubin concentrations and sorbitol dehydrogenase activity. Whole blood immunoglobulin concentrations were < 400 mg/dL in 4 of 15 foals. Fresh whole blood transfusions were administered to 10 of 18 foals. Among the blood factors implicated in 11 foals, one (Dg) had not previously been associated with NI. Of 10 foals that received blood transfusions, 7 had significant improvements in Hct and hemoglobin concentration and 2 had significant improvements in central venous oxygen tension. Fifteen foals survived to discharge.

Conclusions and Clinical Relevance—Data suggest that blood factor Dg may be associated with NI in foals. Liver disease may be concurrent with NI in foals, and NI can develop in foals with inadequate passive transfer of colostral antibodies. Whole blood transfusions were successful at increasing oxygencarrying capacity and improving peripheral tissue oxygenation in NI-affected foals. With appropriate treatment, the prognosis for foals with NI is good. (J Am Vet Med Assoc 2005;227:1276–1283)

Full access
in Journal of the American Veterinary Medical Association

Summary

The clinical efficacy of the lazaroid, tirilazad mesylate, a new therapeutic agent for prophylaxis and treatment of endotoxemia, was evaluated in 24 neonatal Holstein calves. Endotoxemia was induced by iv infusion of commercial Escherichia coli lipopolysaccharide (3.25 µg/kg of body weight) over 3 hours. Group-1 calves were given endotoxin alone; group-2 calves were given an infusion of 0.9% sterile saline solution, then were treated with tirilazad mesylate (1.5 mg/kg) 1 hour after the infusion was started. Group-3 calves were treated with tirilazad mesylate 1 hour after the start of the endotoxin infusion, and group-4 calves were given tirilazad mesylate 1 hour before the start of the endotoxin infusion.

Clinical signs of endotoxemia were mitigated by tirilazad mesylate. In addition, tirilazad mesylate protected calves from endotoxin-induced hyperglycemia; treatment after endotoxin infusion decreased the severity of hypoglycemia and prevented lactic acidosis. Treatment with tirilazad mesylate after initiation of endotoxin infusion was as protective as was pretreatment.

Free access
in American Journal of Veterinary Research

Summary

Gram-negative bacterial infections were documented in 6 neonatal New World camelids (5 llamas and 1 alpaca). The organisms isolated from blood before death or from multiple organs after death were Escherichia coli (n = 3), Actinobacillus sp (n = 1), and Klebsiella pneumoniae (n = 1). Only 2 crias survived, and 1 became blind secondary to retinal detachment and ocular inflammation, which developed after treatment for bacterial infection.

Abnormal events during the perinatal period (prematurity, dystocia, cesarean section, weak at birth) were reported in all 6 crias. Signs of depression, convulsions, and/or coma were observed in all animals. Diarrhea and respiratory distress were also noticed in the 3 crias that died shortly after admission.

Serum immunoglobulins were assessed, but without the benefit of a stall-side test specific for llama immunoglobulins. All crias were suspected to have poor transfer of maternal immunoglobulins. Hemograms and serum biochemical values prior to the initiation of treatment were obtained on 5 of the 6 crias. Total nucleated cells ranged from 1,400 to 23,100 cells/μl. Four of the 5 crias had a left shift, and 2 crias had toxic neutrophils. Serum glucose concentrations, measured in 5 of 6 crias, ranged from 83 to 293 mg/dl. Serum creatinine values were high in 2 of 5 crias, 1 of which had acute tubular necrosis. Three crias with high serum electrolyte (sodium, chloride, or potassium) values subsequently died. Arterial blood gas values were assessed in 3 crias, 1 of which had respiratory alkalosis and mild hypoxemia.

Free access
in Journal of the American Veterinary Medical Association

Summary

Equine neonatal chondrocytes were cultured in three-dimensional fibrin matrices under conditions of immediate implantation or implantation following monolayer culture for 6 days, and 3 cell concentrations (1 × 105, 1 × 106, and 5 × 106 chondrocytes/ cm3). Equine fibrinogen was collected by cryoprecipitation and polymerized by use of activated bovine thrombin. The fibrin implants were harvested and analyzed histologically and biochemically at 3, 7, and 14 days after the chondrocytes were implanted in fibrin. The differentiation ratio (ratio of rounded, chondrocyte-like cells to stellate, fibroblast-like cells) was statistically higher for implants that received 5 × 106 precultured cells at all time periods than for implants that received 1 × 105 or 1 × 106 precultured cells. The differentiation ratio was statistically higher for implants that received 5 × 106 immediately implanted cells than for other implants at 7 days after implantation. At 14 days, implants that received 5 × 106 precultured chondrocytes had a higher differentiation ratio than did implants that received 5 × 106 chondrocytes that had not been precultured. Among implants that received precultured chondrocytes, total glycosaminoglycan and chondroitin sulfate content was lowest for implants that received only 1 × 105 cells. Among implants that received chondrocytes that had not been precultured, glycosaminoglycan content was not significantly different among the 3 cell concentrations, and chondroitin sulfate content was different only between implants that received 5 × 106 vs 1 × 106 cells. Only after the longest incubation period and at the highest cell concentration studied did preculturing of chondrocytes improve maintenance of phenotype. Preculturing did not appear to influence proteoglycan synthesis.

Free access
in American Journal of Veterinary Research

Summary

Age, species, and disease state may substantially alter the disposition and clearance of pharmacologic agents. This is particularly important when drugs with low therapeutic index are used in ill neonates. Pharmacokinetic variables for phenylbutazone were determined in 24- to 32-hour-old healthy and endotoxemic calves after iv administration of a single dose (5 mg/kg of body weight, iv). Elimination halflife was 207 and 168 hours, and clearance was 0.708 and 0.828 ml/kg/h in healthy and endotoxemic calves, respectively. Intravenous infusion of endotoxin at the dose (2 μg/kg over 4 hours) given did not significantly alter any of the calculated pharmacokinetic variables. Serum thromboxane B2 concentration was significantly (P = 0.05) suppressed for 3 hours after phenylbutazone administration in healthy calves and for 4 hours in endotoxin-challenged calves. Daily administration of phenylbutazone (10 mg/kg loading, then 5 mg/kg for 9 days) to healthy and endotoxemic calves failed to induce any lesions consistent with nonsteroidal anti-inflammatory drug toxicosis.

Free access
in American Journal of Veterinary Research