Health and ruminal variables were intensively measured during adaptation to grain-based diets in 6 beef cattle with fistulated rumens. The cows had been maintained on prairie grass hay-supplemented diets, and were converted to a grain-based finishing ration by feeding each successive diet (diets 1-4, respectively) for a period of 7 days. Each cow was evaluated and samples were obtained 3 times each day for the first 5 days that each diet was fed. Health variables monitored were rectal temperature, pulse, respiratory and rumen motility rates, fecal consistency, demeanor, blood pH, and blood glucose and L(+) lactate concentrations. Ruminal variables monitored were pH and glucose, DL-lactate, and volatile fatty acid concentrations of rumen contents. Data were analyzed by use of a multivariate ANOVA. We determined that most of the health variables were within reference rang limits throughout the adaptation period; however, analysis of pulse and respiratory rates indicated that diets 2 and 4 were stressful. Although blood pH continually decreased during feeding of the 4 diets (7.38 to 7.30), blood L(+) lactate and glucose concentrations had large increases only within diet 4. The pH of ruminal contents decreased progressively from 6.8 to 5.3. Rumen glucose concentration was low (< 1 micromole/ml), except with diet 4 in which values were 8 times higher than for other diets. By the end of the study, the ruminal contents of all animals were acidic (pH < 5.5), and, on the basis of higher than background amounts of ruminal glucose and DL-lactate, it was determined that rumen microbial equilibrium had not yet been achieved. Analysis of results of this study suggested that ruminal imbalance could be evaluated by monitoring pulse and respiratory rates, blood pH, and blood glucose concentrations. Assessment of the rumen alone could be accomplished by monitoring the variables of rumen pH, rumen glucose, and DL-lactate concentrations.

Health and ruminal variables were intensively measured during adaptation to grain-based diets in 6 beef cattle with fistulated rumens. The cows had been maintained on prairie grass hay-supplemented diets, and were converted to a grain-based finishing ration by feeding each successive diet (diets 1-4, respectively) for a period of 7 days. Each cow was evaluated and samples were obtained 3 times each day for the first 5 days that each diet was fed. Health variables monitored were rectal temperature, pulse, respiratory and rumen motility rates, fecal consistency, demeanor, blood pH, and blood glucose and L(+) lactate concentrations. Ruminal variables monitored were pH and glucose, DL-lactate, and volatile fatty acid concentrations of rumen contents. Data were analyzed by use of a multivariate ANOVA. We determined that most of the health variables were within reference rang limits throughout the adaptation period; however, analysis of pulse and respiratory rates indicated that diets 2 and 4 were stressful. Although blood pH continually decreased during feeding of the 4 diets (7.38 to 7.30), blood L(+) lactate and glucose concentrations had large increases only within diet 4. The pH of ruminal contents decreased progressively from 6.8 to 5.3. Rumen glucose concentration was low (< 1 micromole/ml), except with diet 4 in which values were 8 times higher than for other diets. By the end of the study, the ruminal contents of all animals were acidic (pH < 5.5), and, on the basis of higher than background amounts of ruminal glucose and DL-lactate, it was determined that rumen microbial equilibrium had not yet been achieved. Analysis of results of this study suggested that ruminal imbalance could be evaluated by monitoring pulse and respiratory rates, blood pH, and blood glucose concentrations. Assessment of the rumen alone could be accomplished by monitoring the variables of rumen pH, rumen glucose, and DL-lactate concentrations. Respiratory rate, blood and rumen content pH, and blood L(+) lactate concentrations were significantly (P < 0.001) affected by time after feeding.

Blood ionized calcium (Ca2+) and pH; plasma lactate concentrations; and total protein, total calcium (CaT), albumin, and phosphorus concentrations in serum were determined in 40 healthy horses before (T1), at the finish line (T2), and 10 minutes after the finish (T3) of the cross-country phase of a 3-dayevent competition. Mean ( +/- SEM) Ca2+ concentrations decreased from 6.22 +/- 0.04 mg/dl at T1 to 5.04 +/- 0.07 mg/dl at T2 (P less than or equal to 0.05). This decrease was accompanied by a nonsignificant increase in CaT between T1 and T2. The mean (+/- SEM) percent ionization of calcium decreased significantly (P less than or equal to 0.05), from 50.9 +/- 2.75% at T1 to 40.3 +/- 3.58% at T2. Significant increases in mean albumin, total protein, phosphorus, and lactate concentrations and a significant decrease in mean pH were observed at T2 (P less than or equal to 0.05). At T3, mean Ca2+ and percent ionization had increased, but remained significantly less than resting values. Mean CaT was significantly decreased at T3, compared with values at T1 and T2. Correlation of mean Ca2+ concentration with all other measured variables at each time was evaluated; correlation coefficients between mean Ca2+ and all other variables were low (r2 less than or equal to 0.38), indicating low biological significance.

Blood ionized calcium (Ca2+) and pH; plasma lactate concentrations; and total protein, total calcium (CaT), albumin, and phosphorus concentrations in serum were determined in 40 healthy horses before (T1), at the finish line (T2), and 10 minutes after the finish (T3) of the cross-country phase of a 3-dayevent competition. Mean (+/- SEM) Ca2+ concentrations decreased from 6.22 +/- 0.04 mg/dl at T1 to 5.04 +/- 0.07 mg/dl at T2 (P less than or equal to 0.05). This decrease was accompanied by a nonsignificant increase in CaT between T1 and T2. The mean (+/- SEM) percent ionization of calcium decreased significantly (P less than or equal to 0.05), from 50.9 +/- 2.75% at T1 to 40.3 +/- 3.58% at T2. Significant increases in mean albumin, total protein, phosphorus, and lactate concentrations and a significant decrease in mean pH were observed at T2 (P less than or equal to 0.05). At T3, mean Ca2+ and percent ionization had increased, but remained significantly less than resting values. Mean CaT was significantly decreased at T3, compared with values at T1 and T2. Correlation of mean Ca2+ concentration with all other measured variables at each time was evaluated; correlation coefficients between mean Ca2+ and all other variables were low (r2 less than or equal to 0.38), indicating low biological significance.

Sonographic and anatomic observations were made of the kidneys of 23 Thoroughbreds or Standardbreds. In an in vitro study of 16 horses, precise correlations were established between the gross anatomic features of the kidneys and their sonographic appearance in images obtained in dorsal, sagittal, transverse, and transverse oblique anatomic planes. The renal cortex had a uniformly mottled echogenicity, and the renal medulla was relatively hypoechogenic, compared with the cortex. Acoustic anisotropy was observed in the cortex and medulla of the cranial and caudal extremities of each kidney. The distinctive renal pelvis was seen in the transverse plane as an echogenic pair of diverging lines that lead to the crescent shaped renal crest in the lateral half of the kidney. In images made in the sagittal plane, the renal pelvis was seen as a pair of parallel echogenic lines separated by the moderately echogenic line of the renal crest. The terminal recesses were best seen in the transverse oblique views of each extremity, where they appeared as moderately echogenic lines in the medulla of the cranial and caudal extremities. The interlobar vessels were represented as irregular echogenic lines in the medulla, and the arcuate vessels were seen as echogenic points at the corticomedullary junction. At the hilus, the renal artery or its branches was located cranial to the renal vein, which in turn was cranial to the position of the proximal portion of the ureter. In an in vivo study of 7 horses, sonographic images of the right kidney were obtained in the sagittal, transverse, and transverse oblique anatomic planes in all horses, with the transducer positioned at the 15th, 16th, or 17th intercostal space; images in the dorsal plane were obtained, however, in only 3 of the horses. For the left kidney, sonographic images were obtained in each of the anatomic planes when the transducer was positioned at the 16th or 17th intercostal space or the paralumbar fossa.

Sonographic and anatomic observations were made of the kidneys of 23 Thoroughbreds or Standardbreds. In an in vitro study of 16 horses, precise correlations were established between the gross anatomic features of the kidneys and their sonographic appearance in images obtained in dorsal, sagittal, transverse, and transverse oblique anatomic planes. The renal cortex had a uniformly mottled echogenicity, and the renal medulla was relatively hypoechogenic, compared with the cortex. Acoustic anisotropy was observed in the cortex and medulla of the cranial and caudal extremities of each kidney. The distinctive renal pelvis was seen in the transverse plane as an echogenic pair of diverging lines that lead to the crescent shaped renal crest in the lateral half of the kidney. In images made in the sagittal plane, the renal pelvis was seen as a pair of parallel echogenic lines separated by the moderately echogenic line of the renal crest. The terminal recesses were best seen in the transverse oblique views of each extremity, where they appeared as moderately echogenic lines in the medulla of the cranial and caudal extremities. The interlobar vessels were represented as irregular echogenic lines in the medulla, and the arcuate vessels were seen as echogenic points at the corticomedullary junction. At the hilus, the renal artery or its branches was located cranial to the renal vein, which in turn was cranial to the position of the proximal portion of the ureter. In an in vivo study of 7 horses, sonographic images of the right kidney were obtained in the sagittal, transverse, and transverse oblique anatomic planes in all horses, with the transducer positioned at the 15th, 16th, or 17th intercostal space; images in the dorsal plane were obtained, however, in only 3 of the horses. For the left kidney, sonographic images were obtained in each of the anatomic planes when the transducer was positioned at the 16th or 17th intercostal space or the paralumbar fossa; rectal location of the transducer gave images in the dorsal and sagittal planes. In this study, a routine sonographic imaging protocol, using standard anatomic planes, enabled each kidney to be examined in its entirety. The protocol provided definition of normal renal sonographic anatomic features and may permit a more informed and accurate recognition of renal pathologic change.

Objective--To study whether end products of 2 pathways of anaerobic energy metabolism, lactate and purines, that accumulate in the blood after intense exercise indicate any relation to exercise performance. Design--Venous blood samples were taken within 1 and 15 minutes after a trotting race of 2,100 m. Animals--16 Clinically healthy Standardbred trotters. Procedure--Blood and plasma lactate concentrations were measured by enzymatic analyzer, and purines, uric acid and allantoin, were determined by high-performance liquid chromatography. The concentrations of metabolites were then correlated to racing time and individual performance indexes that are annually calculated from the percentage of winnings, placings, and starts rejected, average earnings per start, and the racing record. Results--Blood lactate concentration immediately and calculated cell lactate concentration immediately and 15 minutes after the race correlated positively (P < 0.05 to P < 0.01 ) with the individual performance indexes. Plasma lactate concentration was not correlated to the individual performance indexes. Uric acid concentration, immediately and 15 minutes after the race, was negatively correlated (P < 0.05) to the individual performance indexes, and a positive relation (P < 0.05) was found between the highest concentration of uric acid and the racing time. Concentration of allantoin immediately or 15 minutes after the race did not have any significant correlation to the individual performance indexes. Conclusions--Accumulation of lactate in the blood, which was greater in the superior performing horses, may prove to be an useful predictor of anaerobic capacity. The results also indicate that the loss of purine nucleotides was less in the superior performing horses, although further studies are needed to confirm this.

Objective--To study whether end products of 2 pathways of anaerobic energy metabolism, lactate and purines, that accumulate in the blood after intense exercise indicate any relation to exercise performance. Design--Venous blood samples were taken within 1 and 15 minutes after a trotting race of 2,100 m. Animals--16 Clinically healthy Standardbred trotters. Procedure--Blood and plasma lactate concentrations were measured by enzymatic analyzer, and purines, uric acid and allantoin, were determined by high-performance liquid chromatography. The concentrations of metabolites were then correlated to racing time and individual performance indexes that are annually calculated from the percentage of winnings, placings, and starts rejected, average earnings per start, and the racing record. Results--Blood lactate concentration immediately and calculated cell lactate concentration immediately and 15 minutes after the race correlated positively (P < 0.05 to P < 0.01) with the individual performance indexes. Plasma lactate concentration was not correlated to the individual performance indexes. Uric acid concentration, immediately and 15 minutes after the race, was negatively correlated (P < 0.05) to the individual performance indexes, and a positive relation (P < 0.05) was found between the highest concentration of uric acid and the racing time. Concentration of allantoin immediately or 15 minutes after the race did not have any significant correlation to the individual performance indexes. Conclusions--Accumulation of lactate in the blood, which was greater in the superior performing horses, may prove to be an useful predictor of anaerobic capacity. The results also indicate that the loss of purine nucleotides was less in the superior performing horses, although further studies are needed to confirm this.

Investigation of the structure of equine articular cartilage link protein (LP) from individuals ranging in age from 1 to 15 years identified 3 distinct isoforms having molecular weights of 46,000, 43,000, and 41,000. The relative amounts of each of the 3 isoforms altered with age. The largest form did not change with age; however, amounts of the Mr 43,000 and 41,000 forms increased with increasing age. The results suggested that an accumulation, in the extracellular matrix of cartilage, of these 2 smaller products may have arisen from proteolytic cleavage. The complete amino acid sequence of the protein core was determined from complementary DNA products prepared by polymerase chain reaction amplification of cartilage LP mRNA. The sequence had 96% similarity with human LP and with that of other species for which the primary structure has been determined. This high degree of sequence conservation and the isoform data indicate that extracellular processing of LP occurs by similar mechanisms in various species. At the transcription level, equine chondrocytes were found to express LP as 2 abundant mRNA of 5.0 and 3.0 kb, and a smaller mRNA of 1.5 kb. Processing of the LP mRNA in horses, thus, appears to be similar to that found in other species investigated, and although multiple transcripts are present, the coding region remains unaltered and only 1 protein product is made.

Investigation of the structure of equine articular cartilage link protein (LP) from individuals ranging in age from 1 to 15 years identified 3 distinct isoforms having molecular weights of 46,000, 43,000, and 41,000. The relative amounts of each of the 3 isoforms altered with age. The largest form did not change with age; however, amounts of the Mr 43,000 and 41,000 forms increased with increasing age. The results suggested that an accumulation, in the extracellular matrix of cartilage, of these 2 smaller products may have arisen from proteolytic cleavage. The complete amino acid sequence of the protein core was determined from complementary DNA products prepared by polymerase chain reaction amplification of cartilage LP mRNA. The sequence had 96% similarity with human LP and with that of other species for which the primary structure has been determined. This high degree of sequence conservation and the isoform data indicate that extracellular processing of LP occurs by similar mechanisms in various species. At the transcription level, equine chondrocytes were found to express LP as 2 abundant mRNA of 5.0 and 3.0 kb, and a smaller mRNA of 1.5 kb. Processing of the LP mRNA in horses, thus, appears to be similar to that found in other species investigated, and although multiple transcripts are present, the coding region remains unaltered and only 1 protein product is made.

We evaluated the pharmacokinetics of IV administered sodium heparin and the pharmacodynamic effect of heparin on lipoprotein lipase (LPL) activity Horses were allotted to 3 groups. Plasma samples were obtained from each horse before and at various times for 6 hours after heparin administration for determination of heparin concentration, LPL activity, and activated partial thromboplastin time (APTT). The disposition of heparin was dose dependent. The area under the plasma heparin concentration vs time curve (AUC) increased more than proportionally with dose, indicating that heparin elimination was nonlinear. Total clearance of heparin was similar after the 40 and 80 IU/kg of body weight dosages, averaging 0.45 and 0.36 IU/kg/min, respectively. However, after administration of the 120 IU/kg dose, clearance was significantly less than that after the 40 IU/kg dose. The half-life of heparin averaged 53, 70, and 136 minutes after 40, 80, and 120 IU/kg, respectively, with significant differences observed between the low and high doses. In contrast to heparin, the area under the plasma concentration vs time curve for LPL activity increased less than proportionally with dose. Maximal LPL activity observed was independent of dose, averaging 4.8 micromole of free fatty acids/ml/h. The APTT was significantly prolonged for 120 minutes after administration of the 40 IU/kg dose. Correlation coefficients for LPL activity vs either plasma heparin concentration or APTT were less than 0.7, indicating that neither laboratory measure can be used to accurately predict plasma LPL activity.

We evaluated the pharmacokinetics of IV administered sodium heparin and the pharmacodynamic effect of heparin on lipoprotein lipase (LPL) activity Horses were allotted to 3 groups. Plasma samples were obtained from each horse before and at various times for 6 hours after heparin administration for determination of heparin concentration, LPL activity, and activated partial thromboplastin time (APTT). The disposition of heparin was dose dependent. The area under the plasma heparin concentration vs time curve (AUC) increased more than proportionally with dose, indicating that heparin elimination was nonlinear. Total clearance of heparin was similar after the 40 and 80 IU/kg of body weight dosages, averaging 0.45 and 0.36 IU/kg/min, respectively. However, after administration of the 120 IU/kg dose, clearance was significantly less than that after the 40 IU/kg dose. The half-life of heparin averaged 53, 70, and 136 minutes after 40, 80, and 120 IU/kg, respectively, with significant differences observed between the low and high doses. In contrast to heparin, the area under the plasma concentration vs time curve for LPL activity increased less than proportionally with dose. Maximal LPL activity observed was independent of dose, averaging 4.8 micromole of free fatty acids/ml/h. The APTT was significantly prolonged for 120 minutes after administration of the 40 IU/kg dose. Correlation coefficients for LPL activity vs either plasma heparin concentration or APTT were less than 0.7, indicating that neither laboratory measure can be used to accurately predict plasma LPL activity.

We compared the ability of 2 alpha2-adrenergic receptor antagonists, atipamezole and yohimbine, to reverse medetomidine-induced CNS depression and cardiorespiratory changes in lambs. Twenty lambs (7.8 +/- 2.6 kg) were randomly allotted to 4 treatment groups (n = 5). Each lamb was given medetomidine (30 micrograms/kg of body weight, IV), followed in 15 minutes by IV administration of atipamezole (30 or 60 micrograms/kg), yohimbine (1 mg/kg), or 0.9% NaCl (saline) solution. Medetomidine caused lateral recumbency in 1 to 2 minutes in all treated lambs. Medetomidine significantly (P < 0.05) decreased heart rate at 5 and 10 minutes after its administration. Heart rate remained above 120 beats/min, and severe bradycardia (< 70 beats/min) and other arrhythmias did not occur throughout the study. Medetomidine also induced tachypnea in all treated lambs. The tachypnea was abolished by atipamezole and yohimbine, but not by saline solution administration. The medetomidine-induced tachypnea did not significantly affect arterial pH and PaCO2. Arterial oxygen tension was within acceptable range (PaO2 = 71 to 62 mm of Hg), but was lower than expected. Administration of atipamezole, yohimbine, or saline solution did not change PaO2 significantly. Lambs treated with 30 or 60 micrograms of atipamezole/kg were able to walk unassisted in 2.4 +/- 0.4 and 2.3 +/- 0.7 minutes, respectively, whereas yohimbine-and saline-treated lambs did not walk unassisted until 15.6 +/- 2.7 and 73.0 +/- 6.8 minutes later, respectively. Results of this study indicated that medetomidine is a potent CNS depressant in lambs. Atipamezole at dosage of 30 or 60 micrograms/kg was equally effective, and was more effective in antagonizing medetomidine-induced CNS depression than was yohimbine.

We compared the ability of 2 alpha2-adrenergic receptor antagonists, atipamezole and yohimbine, to reverse medetomidine-induced CNS depression and cardiorespiratory changes in lambs. Twenty lambs (7.8 +/- 2.6 kg) were randomly allotted to 4 treatment groups (n = 5). Each lamb was given medetomidine (30 micrograms/kg of body weight, IV), followed in 15 minutes by IV administration of atipamezole (30 or 60 micrograms/kg), yohimbine (1 mg/kg), or 0.9% NaCl (saline) solution. Medetomidine caused lateral recumbency in 1 to 2 minutes in all treated lambs. Medetomidine significantly (P < 0.05) decreased heart rate at 5 and 10 minutes after its administration. Heart rate remained above 120 beats/min, and severe bradycardia (< 70 beats/min) and other arrhythmias did not occur throughout the study. Medetomidine also induced tachypnea in all treated lambs. The tachypnea was abolished by atipamezole and yohimbine, but not by saline solution administration. The medetomidine-induced tachypnea did not significantly affect arterial pH and PaCO2. Arterial oxygen tension was within acceptable range (PaO2 = 71 to 62 mm of Hg), but was lower than expected. Administration of atipamezole, yohimbine, or saline solution did not change PaO2 significantly. Lambs treated with 30 or 60 micrograms of atipamezole/kg were able to walk unassisted in 2.4 +/- 0.4 and 2.3 +/- 0.7 minutes, respectively, whereas yohimbine- and saline-treated lambs did not walk unassisted until 15.6 +/- 2.7 and 73.0 +/- 6.8 minutes later, respectively. Results of this study indicated that medetomidine is a potent CNS depressant in lambs. Atipamezole at dosage of 30 or 60 micrograms/kg was equally effective, and was more effective in antagonizing medetomidine-induced CNS depression than was yohimbine.

Cytologic examination of bronchoalveolar lavage fluid (BALF), including phenotypic analysis of lymphocytes, was performed on 32 Standardbreds with poor race performance and endoscopic examination findings characteristic of inflammatory airway disease (IAD). Nucleated cell counts in BALF from IAD-affected horses were higher than those in control horses; the cytologic profile of BALF in affected horses included mixed inflammation, characterized by mild neutrophilia, lymphocytosis, and monocytosis. Eosinophil and mast cell counts were not higher in the IAD-affected group, compared with those in the control group; however, 4 IAD-affected horses had marked eosinophilia (24.7 +/- 4.8% SEM) in BALF. Phenotypic analysis of lymphocytes in BALF obtained from IAD-affected horses revealed a low proportion of CD4-positive cells and B cells, compared with those in the control group; these findings may have been representative of a greater proportion of non-B, non-T cells (null cells) in horses with IAD. The cytologic profile of BALF obtained from horses with IAD differed from that in horses affected with chronic obstructive pulmonary disease, suggesting that the pathogenesis of inflammation in horses with IAD may differ from that of chronic obstructive pulmonary disease.

Cytologic examination of bronchoalveolar lavage fluid (BALF), including phenotypic analysis of lymphocytes, was performed on 32 Standardbreds with poor race performance and endoscopic examination findings characteristic of inflammatory airway disease (IAD). Nucleated cell counts in BALF from IAD-affected horses were higher than those in control horses; the cytologic profile of BALF in affected horses included mixed inflammation, characterized by mild neutrophilia, lymphocytosis, and monocytosis. Eosinophil and mast cell counts were not higher in the IAD-affected group, compared with those in the control group; however, 4 IAD-affected horses had marked eosinophilia (24.7 +/- 4.8% SEM) in BALF. Phenotypic analysis of lymphocytes in BALF obtained from IAD-affected horses revealed a low proportion of CD4-positive cells and B cells, compared with those in the control group; these findings may have been representative of a greater proportion of non-B, non-T cells (null cells) in horses with IAD. The cytologic profile of BALF obtained from horses with IAD differed from that in horses affected with chronic obstructive pulmonary disease, suggesting that the pathogenesis of inflammation in horses with IAD may differ from that of chronic obstructive pulmonary disease.

Free, autogenous, full-thickness skin grafts were applied to 10 dogs; 5 dogs were given an iron chelator, deferoxamine-10% hydroxyethyl pentafraction starch (DEF-HES; 50 mg/kg of body weight, IV), and 5 dogs were given an equal volume of 10% hydroxyethyl pentafraction starch (HES) in 0.9% saline solution (5 ml/kg, IV). All dogs (DEF-HES/HBO- and HES/HBO-treated) were exposed to 60 minutes of hyperbaric oxygen (HBO) at 2 atmospheres absolute pressure twice daily for 10 days, beginning the day of surgery. The percentage of viable graft on day 10 was lower in HES/HBO-treated-dogs (mean +/- SD, 13.3 +/- 21.3%; median, 3.0%) than in DEF-HES/HBO-treated dogs (64.7 +/- 39.2%; 88.3%; P = 0.095, Mann-Whitney two-tailed test). There was a positive correlation between percentage of viable graft (on day 10) and percentage of haired skin on the graft site (on day 28) for all dogs (r = 0.91) and for HES/HBO-treated dogs (r = 0.97). The DEF-HES/HBO-treated dogs had less consistent correlation (r = 0.67). Perivascular aggregates of foamy cells were observed in the superficial and reticular portions of the dermis and in the subcutaneous tissue on both surfaces of the panniculus muscle in the graft sites of DEF-HES/HBO-treated dogs. These cells were also observed in the dermis, but not subcutaneous tissue of the control skin sections, and in some viscera of DEF-HES/HBO-treated dogs. Deferoxamine appears to attenuate the detrimental effect of HBO and HES on survival of free skin grafts. However, clinical use of HBO is not recommended as adjunct treatment for free skin grafts in dogs in the first 10 days after grafting. Administration of DEF-HES is not recommended because it has failed to improve the survival of free skin grafts, and the consequence of the cellular response seen in this study is undetermined.

Free, autogenous, full-thickness skin grafts were applied to 10 dogs; 5 dogs were given an iron chelator, deferoxamine-10% hydroxyethyl pentafraction starch (DEF-HES; 50 mg/kg of body weight, IV), and 5 dogs were given an equal volume of 10% hydroxyethyl pentafraction starch (HES) in 0.9% saline solution (5 ml/kg, IV). All dogs (DEF-HES/HBO- and HES/HBO-treated) were exposed to 60 minutes of hyperbaric oxygen (HBO) at 2 atmospheres absolute pressure twice daily for 10 days, beginning the day of surgery. The percentage of viable graft on day 10 was lower in HES/HBO-treated-dogs (mean +/- SD, 13.3 +/- 21.3%; median, 3.0%) than in DEF-HES/HBO-treated dogs (64.7 +/- 39.2%; 88.3%; P = 0.095, Mann-Whitney two-tailed test). There was a positive correlation between percentage of viable graft (on day 10) and percentage of haired skin on the graft site (on day 28) for all dogs (r = 0.91) and for HES/HBO-treated dogs (r = 0.97). The DEF-HES/HBO-treated dogs had less consistent correlation (r = 0.67). Perivascular aggregates of foamy cells were observed in the superficial and reticular portions of the dermis and in the subcutaneous tissue on both surfaces of the panniculus muscle in the graft sites of DEF-HES/HBO-treated dogs. These cells were also observed in the dermis, but not subcutaneous tissue of the control skin sections, and in some viscera of DEF-HES/HBO-treated dogs. Deferoxamine appears to attenuate the detrimental effect of HBO and HES on survival of free skin grafts. However, clinical use of HBO is not recommended as adjunct treatment for free skin grafts in dogs in the first 10 days after grafting. Administration of DEF-HES is not recommended because it has failed to improve the survival of free skin grafts, and the consequence of the cellular response seen in this study is undetermined.

Immunoglobulin E is produced in response to parasitic nematodes that undergo blood and tissue migrations. Results of our previous studies indicated that IgE and IgG respond to Dirofilaria immitis in experimentally infected dogs. To determine the association between treatment with the larvicide, diethylcarbamazine (DEC), and antibody responses and to examine the potential influence of infection with a nonfilarid intestinal nematode on isotype-specific immune responses, we monitored, by use of isotype-specific ELISA, separate IgE and IgG responses against D immitis in 4 groups (A-D) of 8 dogs experimentally coinfected with D immitis and Ancylostoma caninum. All dogs were monitored from 2 weeks before inoculation with D immitis, through postinoculation (PI) week 20. Group-B dogs received a daily regimen of 6.6 mg of DEC/kg of body weight. Group-C dogs received 4.95 mg of oxibendazole/kg daily. Group-D dogs received DEC and oxibendazole, equivalent to the daily doses given to dogs of groups B and C. All dogs given oxibendazole had no A caninum at necropsy. Of the groups receiving DEC, 3 group-B dogs each had 1 to 2 D immitis at necropsy. When results of chronologic IgE determination for all groups were statistically compared, only groups B and C had significant (P = 0.0148 and P << 0.00005, respectively) increases in IgE values. Group-C dogs had the highest IgE values from PI week 10 until the end of the study, whereas IgG values were statistically identical to those of group-A dogs. Group-B dogs given only DEC and having the least number of D immitis of all groups, had IgE values that peaked at PI week 6; values were significantly (P = 0.0002) higher than those for all other groups. In Group-B dogs, IgG values increased significantly (P << 0.00005) only at PI week 20 and were significantly (P << 0.00005) decreased after PI week 6, compared with values for all other groups. Group D containing 6 dogs infected with 1 to 18 D immitis found at necropsy had IgE values betwee.

Immunoglobulin E is produced in response to parasitic nematodes that undergo blood and tissue migrations. Results of our previous studies indicated that IgE and IgG respond to Dirofilaria immitis in experimentally infected dogs. To determine the association between treatment with the larvicide, diethylcarbamazine (DEC), and antibody responses and to examine the potential influence of infection with a nonfilarid intestinal nematode on isotype-specific immune responses, we monitored, by use of isotype-specific ELISA, separate IgE and IgG responses against D immitis in 4 groups (A-D) of 8 dogs experimentally coinfected with D immitis and Ancylostoma caninum. All dogs were monitored from 2 weeks before inoculation with D immitis, through postinoculation (PI) week 20. Group-B dogs received a daily regimen of 6.6 mg of DEC/kg of body weight. Group-C dogs received 4.95 mg of oxibendazole/kg daily. Group-D dogs received DEC and oxibendazole, equivalent to the daily doses given to dogs of groups B and C. All dogs given oxibendazole had no A caninum at necropsy. Of the groups receiving DEC, 3 group-B dogs each had 1 to 2 D immitis at necropsy. When results of chronologic IgE determination for all groups were statistically compared, only groups B and C had significant (P = 0.0148 and P << 0.00005, respectively) increases in IgE values. Group-C dogs had the highest IgE values from PI week 10 until the end of the study, whereas IgG values were statistically identical to those of group-A dogs. Group-B dogs given only DEC and having the least number of D immitis of all groups, had IgE values that peaked at PI week 6; values were significantly (P = 0.0002) higher than those for all other groups. In Group-B dogs, IgG values increased significantly (P << 0.00005) only at PI week 20 and were significantly (P << 0.00005) decreased after PI week 6, compared with values for all other groups. Group D containing 6 dogs infected with 1 to 18 D immitis found at necropsy had IgE values between those of group-B dogs and those of non-DEC-treated groups at PI week 6. There was no difference in IgG values between 3 groups at PI week 6, and IgE values were found to be a better correlator than were IgG values to the number of D immitis larvae killed in the tissues during this period. All differences in IgG and IgE values not only correlated with treatment status and number of D immitis adults found at necropsy, but also with the developmental stage of D immitis commonly present in the groups at each time point and the number of adult D immitis found at necropsy.