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Abstract

Objective

To evaluate utility of a method for estimating glomerular filtration rate after a single IV injection of inulin.

Animals

Cats that were renal intact (n = 3) or had renal mass reduced by partial nephrectomy (n = 6).

Procedure

Plasma clearance of inulin (PCIn) was taken as the quotient of the administered dose of inulin (150 mg) divided by the area under the plasma inulin concentration versus time curve determined by 3 methods (PCIn1 – PCIn3). Results for PCIn were compared with simultaneously obtained values for urinary clearance of exogenous creatinine (CCr), an accepted method for the estimation of glomerular filtration rate (GFR) in cats.

Results

Values for PCIn were closely related (R 2 ranged from 0.951 to 0.972, P < 0.0001 in all instances) to CCr. However, PCIn3 provided an estimate of GFR that consistently overestimated CCr.

Conclusion

Determination of PCIn by use of PCIn1 and PCIn2 provided a reliable estimate of GFR in cats of this study.

Clinical Relevance

Determination of PCIn appears to provide a reliable estimate of GFR in cats with early-stage renal disease and no evidence of derangement of body fluid status. In particular, PCIn2, which requires only 3 determinations of plasma inulin concentration, should be considered when an estimate of GFR is sought in a cat with suspected early-stage renal disease. (Am J Vet Res 1996;57:1702–1705)

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

SUMMARY

Ten foals of various breeds were deprived of colostrum from birth to 36 hours of age, then were allotted to 2 groups. Foals of group 1 (n = 6) were given 20 g (200 ml) of purified equine IgG iv in a 10% solution, and foals of group 2 (n = 4) were given 30 g (300 ml) of the same preparation. Total administration time for each 10 g of IgG in 100 ml was approximately 10 minutes. Serum IgG concentration in foals was assessed prior to, between 24 and 48 hours, and at 7 and 14 days after IgG administration.

Between 24 and 48 hours after IgG administration, mean serum IgG concentration in group-1 foals was 425 mg/dl (range, 350 to 480 mg/dl). Mean body weight for this group of foals was 50.3 kg (range, 43.3 to 54.7 kg).

For group-2 foals, mean serum IgG concentration was 768 mg/dl (range, 640 to 920 mg/dl) between 24 and 48 hours after administration of IgG. Foals of this group had mean body weight of 43.2 kg (range, 36.5 to 47.5 kg). Serum IgG concentration in group-2 foals at 24 to 48 hours was significantly (P = 0.005) greater than that in group- 1 foals.

Mean total IgG recovery at 24 to 48 hours, calculated on the basis of 94.5 ml of plasma volume/kg of body weight, was approximately 100%.

Values of IgG measured in all foals 1 and 2 weeks after administration of the IgG concentrate were equivalent to values expected after normal decay of passively acquired IgG. Mild, adverse reactions occurred in 3 of the 10 foals treated (1 group-1 foal and 2 group-2 foals).

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether muscle moment arms at the carpal and metacarpophalangeal joints can be modeled as fixed-radius pulleys for the range of motion associated with the stance phase of the gait in equine forelimbs.

Sample Population—4 cadaveric forelimbs from 2 healthy Thoroughbreds.

Procedure—Thin wire cables were sutured at the musculotendinous junction of 9 forelimb muscles. The cables passed through eyelets at each muscle's origin, wrapped around single-turn potentiometers, and were loaded. Tendon excursions, measured as the changes in lengths of the cables, were recorded during manual rotation of the carpal (180° to 70°) and metacarpophalangeal (220° to 110°) joints. Extension of the metacarpophalangeal joint (180° and 220°) was forced with an independent loading frame. Joint angle was monitored with a calibrated potentiometer. Moment arms were calculated from the slopes of the muscle length versus joint angle curves.

Results—At the metacarpophalangeal joint, digital flexor muscle moment arms changed in magnitude by ≤ 38% during metacarpophalangeal joint extension. Extensor muscle moment arms at the carpal and metacarpophalangeal joints also varied (≤ 41% at the carpus) over the range of joint motion associated with the stance phase of the gait.

Conclusions and Clinical Relevance—Our findings suggest that, apart from the carpal flexor muscles, muscle moment arms in equine forelimbs cannot be modeled as fixed-radius pulleys. Assuming that muscle moment arms at the carpal and metacarpophalangeal joints have constant magnitudes may lead to erroneous estimates of muscle forces in equine forelimbs. (Am J Vet Res 2003;64:351–357)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess the net mechanical load on the distal end of the third metacarpal bone in horses during walking and trotting.

Animals—3 Quarter Horses and 1 Thoroughbred.

Procedures—Surface strains measured on the left third metacarpal bone of the Thorough-bred were used with a subject-specific model to calculate loading (axial compression, bending, and torsion) of the structure during walking and trotting. Forelimb kinematics and ground reaction forces measured in the 3 Quarter Horses were used with a musculoskeletal model of the distal portion of the forelimb to determine loading of the distal end of the third metacarpal bone.

Results—Both methods yielded consistent data regarding mechanical loading of the distal end of the third metacarpal bone. During walking and trotting, the distal end of the third metacarpal bone was loaded primarily in axial compression as a result of the sum of forces exerted on the metacarpal condyles by the proximal phalanx and proximal sesamoid bones.

Conclusions and Clinical Relevance—Results of strain gauge and kinematic analyses indicated that the major structures of the distal portion of the forelimb in horses acted to load the distal end of the third metacarpal bone in axial compression throughout the stance phase of the stride.

Full access
in American Journal of Veterinary Research