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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine the estrogen receptor (ER) content of canine mammary gland tumors by use of immunohistochemical (IHC) examination of formalin-fixed sections.

Sample Population

21 mammary gland tumors from 20 adult dogs.

Procedure

ER were detected in formalin-fixed tissues, using an avidin-biotin alkaline phosphatase IHC assay and were quantified on fresh-frozen tumor samples, using a modified dextran-coated charcoal (DCC) assay.

Results

7 of 21 tumors had visually detectable nuclear ER by use of IHC staining, whereas 8 of 21 tumors were positive for ER by use of the DCC assay. The ER-positive cells in 5 IHC-positive tumors were epithelial cells with histologic criteria of early malignancy. The remaining 2 ER-positive tumors detected by use of IHC had ER-positive mast cells within areas of connective tissue around the tumor.

Conclusions

Immunohistochemistry is an additional method for detection of ER in canine mammary tumors. The major advantage of this type of assay is that it may be performed on formalin-fixed tissues, and individual ER-positive cells may be identified. Discovery of ER-positive mast cells by use of IHC is of concern, particularly if the ER status of a tumor is based on DCC results alone.

Clinical Relevance

Because most canine mammary tumors are fixed in formalin prior to histologic evaluation, an IHC assay that identifies ER-positive cells is desirable. Adjunctive antiestrogen therapy could be administered to dogs with ER-positive tumors. (Am J Vet Res 1999;60:627–630)

Free access
in American Journal of Veterinary Research

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

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

Four young horses of various breeds and suffering from atrial fibrillation died of heart failure. All had markedly high pulmonary arterial pressure, right-sided cardiomegaly, and lack of histologic lesions in the right atrium or pulmonary parenchyma. Three horses had hypertrophy and/or necrosis of the tunica media of the pulmonary vasculature. Clinical signs of disease, physiologic data, and pathologic findings indicated that these horses had primary pulmonary hypertension with secondary right-sided cardiac ventricular hypertrophy and dilatation, atrial fibrillation, and heart failure.

Free access
in Journal of the American Veterinary Medical Association

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