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Abstract

Objective—To determine effects of dietary lipid and protein on plasma lipoprotein and free fatty acid concentrations and hepatic fatty acid synthesis during weight gain and rapid weight loss in cats.

Animals—24 ovariohysterectomized cats.

Procedure—Cats were fed a high energy diet until they gained 30% of their ideal body weight and then randomly assigned to receive 1 of 4 weight reduction diets (6 cats/diet) at 25% of maintenance energy requirements. Diets contained a low or high quality protein source and a lipid source deficient or sufficient in long chain essential fatty acids. Plasma samples and liver biopsy specimens were obtained before and after weight gain and during and after weight loss for determination of free fatty acid, triglyceride, and lipoprotein concentrations. Synthesis of these substances was measured by use of isotope enrichment.

Results—Plasma total cholesterol concentration and concentration of lipoprotein fractions increased after weight gain, compared with baseline values. Weight loss resulted in a significant decrease in concentrations of all lipoprotein fractions except high density lipoprotein. High density lipoprotein concentration was significantly greater in cats fed diets containing an oil blend, compared with cats fed diets containing corn oil. Fatty acid synthesis after weight loss was below the detection limit of the measurement technique.

Conclusions and Clinical Relevance—In cats undergoing rapid weight loss there is neither increased triglyceride synthesis nor decreased transport of very low density lipoproteins from the liver, suggesting that their involvement in the development of hepatic lipidosis may be minimal. (Am J Vet Res 2000;61:566–572)

Full access
in American Journal of Veterinary Research

Summary

Effects of restricted tube-feeding (25% of energy requirements) of protein, lipid, or carbohydrates on body weight loss; hematologic and clinical chemical variables; plasma lipid and amino add concentrations; nitrogen balance; and hepatic histologic features and lipid concentrations were compared with values in voluntary-fasting cats (control, con). Twelve obese cats (6.1 ± 0.1 kg, > 40% above optimal body weight) were randomly assigned to 4 matched treatment groups (n = 3)—protein (pro), lipid (lip), carbohydrate (cho), and con—and were offered a low-palatability diet for 4 weeks. Cats of the pro, lip, and cho groups were also tube-fed isocaloric amounts (88 kcal of metabolizable energy) of a casein-soybean protein mixture, com oil, or a dextrin-dextrose mixture, respectively, during the 4 weeks. All cats fasted, rather than eat the low-palatability purified diet. Cats of the pro group lost weight at a lower rate (P < 0.05) than did cats of other groups. After 4 weeks of fasting, serum alkaline phosphatase activities were higher than reference values in all cats of the con and lip groups and in 2 cats of the cho group. At that time, 1 cat of the lip group had lethargy, hepatomegaly, and hyperbilirubinemia. Total hepatic lipid and triglyceride concentrations increased in all groups during the study, but the increase was significantly (P < 0.05) less in cats of the pro group, compared with those of the con and lip groups, and those of the cho group, compared with those of the lip group. Hepatic total lipid and triglyceride concentrations correlated well with lipid score for liver biopsy specimens when lipidosis was mild or severe, but not as well in association with the intermediate lipidosis. Cats of the PRO group were in nitrogen balance after 2 weeks of fasting. All other cats remained in negative nitrogen balance during the fast, although less nitrogen was lost by cats of the cho and lip groups than by cats of the con group. Plasma aminograms indicated that methionine and arginine might become limiting for protein synthesis during fasting in cats.

Results indicate that dietary protein reduces hepatic lipid accumulation and nitrogen balance is maintained during rapid weight loss in obese cats. Ingestion of only lipids increases the risk of inducing hepatic lipidosis. Ingestion of carbohydrates reduces hepatic lipid accumulation, but is not as effective as protein in preventing all the clinical manifestations of hepatic lipidosis.

Free access
in American Journal of Veterinary Research

SUMMARY

Protein concentration was determined, using the Bradford technique, in tears from cats with normal corneas and from cats with corneal sequestrum. Tears from the former group contained 5.81 ± 2.29 mg of protein/ml; those from corneal sequestrum-affected cats contained 6.21 ± 2.21 mg/ml. Difference between the 2 values was not significant. Molecular weight determination was made, using 4 to 20% sodium dodecyl sulfate-polyacrylamide gels. Molecular mass of proteins ranged from 263 to 14 kDa. There was no detectable difference in the band patterns for the 2 groups.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To describe the pulsed-wave Doppler tracing of the equine lateral palmar digital artery and its modification in relation to standardized changes in posture.

Animals—17 healthy Saddlebred horses.

Procedure—Pulsed-wave Doppler examinations of left and right lateral palmar digital arteries of the horses were performed. The baseline examination was performed on each forelimb while horses were standing squarely with the body weight equally distributed among the 4 limbs (BED position). For each forelimb, the examination was repeated during 3 standardized modifications of the horse's posture (non–weightbearing [NWB] position, full weight-bearing [FWB] position, and a position involving hyperextension of the distal interphalangeal joint [HE position]). In each position, mean values of systolic peak velocity, first and second diastolic peak velocity, end-diastolic velocity, mean velocity, and resistive index were calculated. Data obtained in each different posture were compared statistically.

Results—No significant differences in blood flow variables were detected between the left and right forelimbs. However, significant differences were detected in values of first diastolic velocity, second diastolic velocity, mean velocity, and resistive index between the NWB position and FWB position. Also, end-diastolic velocity in the NWB position was significantly different from that recorded in the HE position.

Conclusions and Clinical Relevance—The pulsedwave Doppler tracing of the equine lateral palmar digital artery was modified considerably with changes in posture. This suggests that the use of a precisely standardized posture for horses is required to obtain repeatable data. (Am J Vet Res 2004;65:1211–1215)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the influence of age, body weight (BW), heart rate (HR), sex, and left ventricular shortening fraction (LVSF) on transmitral and pulmonary venous flow in clinically normal dogs.

Animals—92 client-owned dogs 3 months to 19 years old.

Procedure—Transthoracic Doppler echocardiography recordings of transmitral flow and pulmonary venous flow were obtained in conscious unsedated dogs. Influence of age, BW, HR, sex, and LVSF on diastolic variables was assessed, using statistical methods such as ANOVA on ranks and univariate and multivariate forward stepwise linear regression analyses.

Results—Age significantly influenced isovolumic relaxation time (IVRT; r = 0.56), ratio between peak velocity of the early diastolic mitral flow wave-to-peak velocity of late diastolic mitral flow wave (E:A; r = –0.44), deceleration time of early diastolic mitral flow (DTE; r = 0.26), and peak velocity of atrial reversal pulmonary venous flow wave (AR-wave; r= 0.37). Significant changes of mitral inflow and pulmonary venous flow variables were evident only in dogs > 6 and > 10 years old, respectively. Body weight significantly influenced DTE ( r = 0.63), late diastolic flow duration ( r= 0.60), and AR duration ( r= 0.47), whereas HR significantly affected DTE ( r = –0.34), IVRT ( r= –0.33), and peak velocity of AR ( r= 0.24). Sex or LVSF (range 22 to 48%) did not influence any echocardiographic variables.

Conclusions and Clinical Relevance—Age, BW, and HR are important factors that affect filling of the left atrium and left ventricle in clinically normal dogs. (Am J Vet Res 2001;62:1447–1454)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate the association between airway reactivity and age, sex, body weight, and radiographic findings in cats.

Animals—32 mature cats that constituted 2 age groups (17 young cats that were 1 to 2 years old and 15 old cats that were 12 to 13 years old).

Procedure—Cats were placed in the chamber of a barometric whole-body plethysmograph (volume, 38 L), and box pressure was measured at baseline and after aerosol administration of increasing concentrations of carbachol. Airway reactivity was assessed by monitoring increases in enhanced pause (PENH), a unitless variable that measures bronchoconstriction as derived from dose-response curves. The endpoint chosen was the provocative concentration of carbachol that increased PENH to 300% of the baseline value (PCPENH300).

Results—We did not find a correlation between PCPENH300 and sex, body weight, number of eosinophils, PENH before bronchoconstriction, respiratory frequency, tidal volume, or minute ventilation. Airway reactivity was significantly less in the old cats (mean ± SD PCPENH300, 0.578 ± 0.051%), compared with the value for the young cats (0.053 ± 0.006%). Radiographic patterns differed significantly between groups of cats; a greater proportion of old cats (12/15) had bronchointerstitial patterns, compared with the proportion of young cats (4/17).

Conclusion and Clinical Relevance—These data support the notion that age exerts a strong influence on airway reactivity in adult cats, and radiographic differences suggest that structural changes in older cats may contribute to this effect. These findings have important implications for interpretation of results of airway reactivity tests in cats. (Am J Vet Res 2003;64:26–31)

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in American Journal of Veterinary Research

Abstract

Objective

To evaluate the effect of high-molecular weight (MW) dextran macromolecules on low-flow ischemia and reperfusion of the large colon in horses.

Design

Horses subjected to low-flow ischemia and reperfusion of the large colon were treated with either 0.9 NaCI (group 1, n = 6) or high-MW dextran (group 2, n = 6) solutions.

Animals

12 adult horses.

Procedure

Horses were subjected to 3 hours' low-flow ischemia followed by 3 hours' reperfusion. A dose of either 0.9% NaCI or a 6% solution of high-MW (250,000) dextran (10 ml/kg of body weight) was administered IV, 30 minutes prior to reperfusion. Hemodynamic variables were recorded at 30-minute intervals. Systemic arterial and colonic venous blood were collected for determination of PCV, plasma total protein, and whole blood lactate concentrations, and for blood gas and oximetry analyses. Histologic examination of large-colon biopsy specimens was performed.

Results

Mean arterial pressure was greater in group-2 horses, compared with group-1 horses, from 3 to 3.25 hours, but there were no significant differences between groups for any of the other hemodynamic variables. Compared with baseline values, colonic blood flow was significantly lower from 0.5 to 3 hours and was significantly greater from 3.25 to 6 hours. Arterial and colonic venous PCV were significantly lower than baseline values from 3 to 3.25 hours, and at 3 hours, respectively, in group-2 horses. These values were significantly lower in group-2 horses, from 3 to 6 and 3 to 5 hours, respectively. There was significant mucosal necrosis, hemorrhage, edema, and neutrophil infiltration in horses of both groups; however, there were no significant differences between the 2 groups.

Conclusions

High-MW dextran did not protect the colonic mucosa from low-flow ischemia and reperfusion; there were no deleterious effects on colonic mucosa or on systemic hemodynamic or metabolic variables.

Clinical Relevance

Reperfusion with high-MW dextran solution probably would not protect the large colon from ischemia-reperfusion injury associated with large-colon volvulus. (Am J Vet Res 1996;57:1067–1073)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To examine effects of dietary protein quality (casein [CA] vs corn gluten [CG]) and dietary lipids (corn oil [CO] vs oil blend [OB] rich in long-chain polyunsaturated fatty acids [LCPUFAs]) on fatty acid composition in liver and adipose tissue after weight loss in overweight cats.

Animals—24 ovariohysterectomized adult cats.

Procedure—Cats were allowed ad libitum access to a high-quality diet until they weighed 30% more than their ideal body weight. Cats were then randomly assigned to 1 of 4 weight-reduction diets (6 cats/diet) and were fed 25% of maintenance energy requirements per day. Diets consisted of CG–CO, CA–CO, CG–OB, and CA–OB, respectively, and were fed until cats lost weight and returned to their original lean body mass. Liver biopsy specimens and samples of perirenal, subcutaneous, and abdominal fat were obtained and analyzed for fatty acid content.

Results—Following weight loss, fatty acid composition of the liver and adipose tissue was primarily affected by protein quality in that cats fed CA had significantly higher percentages of 20:4(n-6) and 22:6(n-3) fatty acids than those fed CG. Cats fed the CG–CO diet had the lowest concentrations of LCPUFAs, suggesting that dietary lipids and protein quality each influence fatty acid composition in tissues.

Conclusions and Clinical Relevance—These data provide direct evidence that dietary protein quality alters fatty acid composition of tissues during weight loss in cats. The fatty acid patterns observed suggest that protein quality may alter fatty acid composition through modulation of desaturase activity. (Am J Vet Res 2003;64:310–315)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate efficacy and safety of IP administration of high-molecular-weight carboxymethylcellulose (HMW CMC) for the prevention of postoperative intra-abdominal adhesions in ponies.

Animals—10 ponies.

Procedure—A 1% solution of HMW CMC was instilled intra-abdominally prior to surgery in 5 ponies, whereas 5 control ponies did not receive HMW CMC. Postoperative adhesions were induced by use of a bowel-abrasion method comprising laparotomy, typhlotomy, and abrasion of jejunal serosa at multiple sites with placement of 3 sutures at each site. Day of surgery was day 0. After surgery, ponies were monitored, and hematologic, serum biochemical, and peritoneal fluid analyses were performed on days 1, 2, 3, 5, 7, and 10. On day 10, ponies were euthanatized. Intra-abdominal adhesions were recorded, and tissue samples were collected for histologic examination.

Results—A significantly greater number of adhesions, number of multiple adhesions, and mean incidence of adhesions were identified in control ponies, compared with CMC-treated ponies. Mean peritoneal fluid WBC count on day 7 and serum fibrinogen concentrations on days 5 and 7 were significantly higher in control ponies, compared with CMC-treated ponies. Results of serum biochemical analyses did not differ significantly between the 2 groups.

Conclusions and Clinical Relevance—Intra-abdominal use of 1% HMW CMC during surgery was effective for preventing postoperative adhesions in ponies. Use of HMW CMC did not have detrimental effects on wound healing, intra-abdominal defenses, or patient health. A 1% solution of HMW CMC may be used routinely during abdominal surgery of horses for prevention of postoperative adhesions. (Am J Vet Res 2002;63:1448–1454)

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in American Journal of Veterinary Research

Abstract

Objective—To determine pharmacokinetic variables and to evaluate the influence on clotting times after SC administration of single doses of dalteparin and enoxaparin to horses.

Animals—5 healthy adult horses.

Procedure—The study was designed as a 4-period crossover study. Each horse received a single SC injection of dalteparin (50 and 100 anti-Xa U/kg) and enoxaparin (40 and 80 anti-Xa U/kg). Plasma anti-Xa activities and clotting times were measured, and pharmacokinetic variables were determined. Absolute and relative maximal prolongation of clotting times was calculated, and correlation between plasma anti-Xa activities and clotting times was determined.

Results—The SC administration of each of the doses of the 2 preparations was well tolerated. Time course of the anti-Xa activities could be described in a 1-compartment model. Comparison of low- and high-dose treatments revealed a disproportionate increase of the area under the plasma activity-time curve and prolongation of the terminal half-life, but the increase in maximum plasma activity was proportionate, and peak plasma concentrations corresponded with concentrations recommended in human medicine. There were only mild changes in activated partial thromboplastin time (aPTT), whereas the influence on thrombin time (TT) was greater, dose-dependent, and more variable. A weak-to-moderate correlation between aPTT and plasma anti-Xa activities and a moderate-tostrong correlation between TT and plasma anti-Xa activities were found.

Conclusion and Clinical Relevance—Pharmacokinetic and anticoagulatory properties of low-molecular- weight heparins in horses are similar to those found in humans. Once-daily SC administration of dalteparin or enoxaparin may be useful as an anticoagulatory treatment in horses. (Am J Vet Res 2002; 63:868–873)

Full access
in American Journal of Veterinary Research