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Summary

Effective renal plasma flow (erpf) was evaluated, using the measurement of p-aminohippurate clearance (cl pah ) and quantitative renal scintigraphy (qrs) with 99mTc-mercaptoacetyltriglycine (99mTc-MAG3). The cl pah and qrs determinations were made in 6 dogs: 2 determinations for each dog before, and 1 determination after induction of renal failure by administration of amphotericin B. Least-squares regression analysis was used to derive an equation to estimate erpf from qrs data. The results indicated that qrs, using 99mTc-MAG3, correlated reasonably well (r = 0.82, P < 0.001) with erpf determined from the cl pah value. The right kidney contributed 53.3% of global erpf (P = 0.002). Hepatobiliary excretion of 99mTc-MAG3 was variable within each dog. There was not a consistent pattern with respect to time or renal function. All dogs had nausea or emesis, or both, after iv administration of 99mTc-MAG3. The qrs method with 99mTc-MAG3 provides an adequate means to estimate erpf in healthy dogs and dogs with renal failure.

Free access
in American Journal of Veterinary Research

Summary

A nuclear imaging technique of the stomach, using technetium pertechnetate (99mTcO4), was evaluated in healthy dogs. The stomach was first insufflated with room air, then filled with barium sulfate to induce mild distention, outlining the gastric wall. Six dogs were imaged twice: initially without use of drugs that might affect gastric secretion of 99mTcO4, then after pretreatment with cimetidine and glycopyrrolate. These scans established the appearance of the normal (control) stomach and compared the quality of the image in the same dogs not pretreated, then pretreated with cimetidine and glycopyrrolate before administration of 99mTcO4. Avascular defects were then surgically created on the greater curvature of the stomach of the same 6 dogs, and gastroscintigraphy was performed in similar manner. Significant (P < 0.05) quantitative differences were detected in the gastric images for scans of the avascular area, compared with various control scans. Qualitative assessment had overall accuracy of 90.28%. Results of the study reported here indicate that nuclear imaging can be a valuable diagnostic technique for detecting ischemic areas in the gastric wall of dogs.

Free access
in American Journal of Veterinary Research

Summary

To evaluate the use of technetium pertechnetate (99mTcO4) as a means of estimating gastric mucosal integrity, nuclear images of the empty stomach were obtained from 6 dogs at 20, 40, 60, 120, 180, and 240 minutes after iv administration of the radiopharmaceutical. Blood and gastric secretion samples were collected during the same time intervals. The left lateral-view image of the stomach was used to calculate the relative fraction of the dose in the stomach and the count density ratio. Between 20 and 40 minutes and 40 and 60 minutes, significant differences (P < 0.001) were apparent in the amount of 99mTcO4 in the stomach. Blood concentration of 99mTcO4 decreased significantly (P < 0.001), whereas gastric secretion concentration increased significantly (P < 0.001) over time. Qualitative assessment of the gastric nuclear scans and the statistical analytic results indicated that the optimal time for imaging the canine stomach was between 40 and 60 minutes after radiopharmaceutical administration. In a second study, the same dogs were pretreated with the H2-receptor antagonist cimetidine and the cholinergic antagonist glycopyrrolate to block gastric secretions. Over time, changes in the relative dose fraction in the stomach and the density ratio were the same as values obtained during the experiment performed without use of cimetidine and glycopyrrolate. Results of the study indicate that nuclear imaging with 99mTcO4 outlines normal canine gastric mucosa and that pretreatment with cimetidine and glycopyrrolate has no effect on the quality of the gastric image.

Free access
in American Journal of Veterinary Research

Summary

The nuclear imaging technique known as quantitative renal scintigraphy was validated as a means to assess the kidney function of cats. Renal function tests were performed in 6 healthy cats and 3 cats with clinical manifestations of kidney failure. In addition, the nephrotoxic drugs, gentamicin sulfate, or amphotericin B were used in an attempt to induce renal failure in 4 cats. Using linear regression analysis, equations were derived to estimate the glomerular filtration rate (gfr) on the basis of the renal percent uptake of 99mTc-diethylenetriami-nepentaacetic acid (99mTc-dtpa). One-way anova and Student’s t test were used to evaluate treatment effects on clearances of inulin and creatinine, percent uptake of 99mTc-dtpa, and serum creatinine concentrations. The results show that the percent uptake of 99mTc-dtpa by the kidneys correlated well with the GFR obtained through the clearance of inulin. Thus, it was concluded that quantitative renal scintigraphy, using 99mTc-dtpa as a marker of kidney function, is an adequate technique to estimate the kidney function of healthy cats and cats with functional renal impairment. The best estimate of the gfr of cats, using the percentage dose of 99mTc-dtpa, was obtained on the 1- to 3-minute postinjection interval of the marker, using data that was background-subtracted, but not corrected for tissue absorption of gamma rays or binding of 99mTc-DTPA to plasma proteins. There was no significant difference in the mean inulin clearance, creatinine clearance, or percent uptake of 99mTc-dtpa between the 3 treatment groups of this study. Therefore, it was concluded that neither gentamicin nor amphotericin B are useful drugs in eliciting losses of feline kidney function that may be measurable through the procedures used in this study. Contrary to all other gfr studies in the cat, this study did not use any form of pharmacologic restraint. Therefore, the findings from this study are expected to reflect accurately the true gfr of healthy, nonanesthetized cats.

Free access
in American Journal of Veterinary Research

Summary:

Retrospective radiographic and scintigraphic analyses were performed on 27 fractures of the distal phalanx in 25 horses. Location of 99mtechnetium methylene diphosphonate (99mTc-mdp) uptake was compared with fracture line location as seen on radiography. Intensity (intense, moderate, mild) and pattern (focal, diffuse) of 99mTc-mdp uptake was recorded and compared with duration of fracture. Nine horses were monitored during convalescence by obtaining additional scintigraphic views 3 to 68 months after injury.

Palmar scintigraphic views had evidence of focal areas of increased 99mTc-mdp uptake that corresponded to fracture line location as seen on radiography. Lateral scintigraphic views had evidence of diffuse increased uptake. There was a significant (P < 0.01) association between duration of fracture and intensity of uptake, with fractures < 3 months in duration more likely to have intense focal uptake. All fractures < 10 days in duration had intense focal uptake. As fracture age increased, 99mTc-mdp uptake became less intense and more diffuse. Three fractures not evident on radiography had evidence of 99mTc-mdp uptake on scintigraphy. Stall rest resulted in decreased 99mTc-mdp uptake in 6 of 9 horses, but increased uptake was still visible in all horses between 4 and 25 months after injury. The only scintigraphic view without evidence of increased uptake was that obtained from a horse reexamined 68 months after injury.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate distribution and intensity of 99mTc-methylene diphosphonate (99mTc-MDP) uptake in the navicular area in horses with forelimb lameness isolated to the palmar aspect of the foot.

Design

Prospective, case-controlled study.

Animals

7 horses with clinical signs of navicular syndrome and 7 control horses.

Procedure

Palmar view, soft tissue-phase scintigraphic images of the foot were obtained between 7 and 12 minutes after injection of 120 to 170 mCi of 99mTc-MDP. Lateral and palmar view, bone-phase images were obtained at 30 minutes and 1, 2, and 4 hours after injection. Palmar views were evaluated by determining the ratio of image density in the navicular area to mean image density in the distal phalangeal area. Palmar and lateral view, bone-phase images were also scored on the basis of navicular area intensity (intense = 3, moderate = 2, mild = 1, and no uptake = 0). Density ratios and mean scores were evaluated as a three-way ANOVA.

Results

Mean navicular-to-distal phalangeal density ratio for affected horses (1.77) was significantly (P = 0.003) greater than that for control horses (0.97). The mean subjective score for affected horses when evaluating palmar views only (1.85) and when evaluating palmar and lateral view pairs together (1.99) was significantly (P < 0.01) higher than scores for control horses (0.51, 0.62). Images obtained 1 hour after injection were as good at differentiating affected from control horses as images obtained between 2 to 4 hours after injection.

Conclusion

A substantial number of horses with palmar foot pain have increased scintigraphic uptake within the navicular bone 1 to 4 hours after injection of 99mTc-MDP. Lateral view, bone-phase images are less sensitive than palmar view, bone-phase images in revealing navicular area uptake.

Clinical Relevance

A combination of lateral and palmar view scintigraphic images obtained between 1 and 4 hours after injection of 99mTc-MDP is a useful diagnostic aid in evaluating navicular bone involvement in horses with forelimb lameness isolated to the palmar aspect of the foot. (Am J Vet Res 1996;57:415–421)

Free access
in American Journal of Veterinary Research

Summary

Effective renal plasma flow (erpf) was evaluated, using continuous-infusion p-aminohippurate clearance (cl pah ) and single-injection plasma clearance of technetium-99m mercaptoacetyltriglycine (99mTc-MAG3; cl mag3) methods. Simultaneous clearance determinations were made in 6 dogs: 2 determinations for each dog before, and 1 determination after renal failure was induced by administration of amphotericin B. Linear regression analysis was used to derive an equation to estimate erpf from cl mag3 after the single iv injection. A Student’s t-test was used to compare pharmacokinetics between the dogs when they were healthy and when they were in renal failure. An F-test was used to determine the appropriate Student’s t-test. Results indicated that cl mag3 correlated reasonably well (r = 0.83, P < 0.0001) with erpf obtained from the cl pah value. The volume of distribution and elimination of 99mTc-MAG3 decreased during renal failure. Although there was minimal binding of 99mTc-MAG3 to erythrocytes, it was significantly (P = 0.0008) lower during renal failure. Protein binding was not significantly different during renal failure. All dogs had signs of nausea and emesis at variable times after injection of 99mTc-MAG3. Determination of cl mag3 after a single injection provides an adequate means to rapidly assess erpf in dogs. The technique could easily be performed in dogs with renal disease, thus providing valuable information regarding progression of naturally acquired renal failure.

Free access
in American Journal of Veterinary Research

Objective

To evaluate efficacy and nephrotoxicity of amphotericin B lipid complex used for treatment of dogs with naturally developing blastomycosis.

Design

Prospective clinical trial.

Animals

11 dogs with blastomycosis.

Procedure

All dogs were treated with an amphotericin B lipid complex. Two dogs received a cumulative dose of 8 mg/kg of body weight, 1 received a cumulative dose of 10 mg/kg, and 8 received a cumulative dose of 12 mg/kg.

Results

The 2 dogs that received a cumulative dose of 8 mg/kg and 1 of the dogs that received a cumulative dose of 12 mg/kg had a relapse of blastomycosis within 30 days after treatment. Seven of the remaining 8 dogs were clinically free of blastomycosis 6 months after treatment. One dog died of an unrelated cause 5.5 months after treatment, but did not have clinical signs of blastomycosis at the time of death. There were not any adverse clinical effects attributable to drug administration in any of the dogs in this study, and none of the dogs developed clinical signs of renal disease or failure.

Clinical Implications

Amphotericin B lipid complex was a safe and effective treatment for blastomycosis in these dogs. (J Am Vet Med Assoc 1996;209:2073–2075)

Free access
in Journal of the American Veterinary Medical Association