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  • Author or Editor: Dennis J. Chew x
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Abstract

Objective—To evaluate calcium balance and parathyroid gland function in healthy horses and horses with enterocolitis and compare results of an immunochemiluminometric assay (ICMA) with those of an immunoradiometric assay (IRMA) for determination of serum intact parathyroid hormone (PTH) concentrations in horses.

Animals—64 horses with enterocolitis and 62 healthy horses.

Procedures—Blood and urine samples were collected for determination of serum total calcium, ionized calcium (Ca2+) and magnesium (Mg2+), phosphorus, BUN, total protein, creatinine, albumin, and PTH concentrations, venous blood gases, and fractional urinary clearance of calcium (FCa) and phosphorus (FP). Serum concentrations of PTH were measured in 40 horses by use of both the IRMA and ICMA.

Results—Most (48/64; 75%) horses with enterocolitis had decreased serum total calcium, Ca2+, and Mg2+ concentrations and increased phosphorus concentrations, compared with healthy horses. Serum PTH concentration was increased in most (36/51; 70.6%) horses with hypocalcemia. In addition, FCa was significantly decreased and FP significantly increased in horses with enterocolitis, compared with healthy horses. Results of ICMA were in agreement with results of IRMA.

Conclusions and Clinical Relevance—Enterocolitis in horses is often associated with hypocalcemia; 79.7% of affected horses had ionized hypocalcemia. Because FCa was low, it is unlikely that renal calcium loss was the cause of hypocalcemia. Serum PTH concentrations varied in horses with enterocolitis and concomitant hypocalcemia. However, we believe low PTH concentration in some hypocalcemic horses may be the result of impaired parathyroid gland function. ( Am J Vet Res 2001;62:938–947)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To clone and sequence the cDNA for feline preproparathyroid hormone (preproPTH) and to compare that sequence with other known parathyroid hormone (PTH) sequences.

Sample Population—Parathyroid glands from 1 healthy cat.

Procedure—A cDNA library was constructed in λ phage from feline parathyroid gland mRNA and screened with a radiolabeled canine PTH probe. Positive clones were sequenced, and nucleic acid and deduced amino acid sequences were analyzed and compared with known preproPTH and PTH sequences.

Result—Screening of approximately 2 X 105 recombinant plaques revealed 3 that hybridized with the canine PTH probe; 2 clones comprised the complete sequence for feline preproPTH. Feline preproPTH cDNA consisted of a 63-base pair (bp) 5'-untranslated region (UTR), a 348-bp coding region, and a 326-bp 3'-UTR. The coding region encoded a 115-amino acid peptide. Mature feline PTH consisted of 84 amino acids. Amino acid sequence analysis revealed that feline PTH was > 83% identical to canine, bovine, swine, equine, human, and macaque PTH and 69, 71, and 44% identical to mouse, rat, and chicken PTH, respectively. Within the region responsible for hormonal activity (amino acids 1 to 34), feline PTH was > 79% identical to other mammalian PTH sequences and 64% identical to the chicken sequence.

Conclusions and Clinical Relevance—The amino acid sequence of PTH is conserved among mammalian species. Knowledge of the cDNA sequence for feline PTH may be useful to investigate disturbances of calcium metabolism and alterations in PTH expression in cats. (Am J Vet Res 2002;63:194–197)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine efficacy of a protocol for managing urethral obstruction (UO) in male cats without urethral catheterization.

Design—Clinical trial.

Animals—15 male cats with UO in which conventional treatment had been declined.

Procedures—Laboratory testing and abdominal radiography were performed, and cats with severe metabolic derangements or urinary calculi were excluded. Treatment included administration of acepromazine (0.25 mg, IM, or 2.5 mg, PO, q 8 h), buprenorphine (0.075 mg, PO, q 8 h), and medetomidine (0.1 mg, IM, q 24 h) and decompressive cystocentesis and SC administration of fluids as needed. Cats were placed in a quiet, dark environment to minimize stress. Treatment success was defined as spontaneous urination within 72 hours and subsequent discharge from the hospital.

Results—Treatment was successful in 11 of the 15 cats. In the remaining 4 cats, treatment was considered to have failed because of development of uroabdomen (n = 3) or hemoabdomen (1). Cats in which treatment failed had significantly higher serum creatinine concentrations than did cats in which treatment was successful. Necropsy was performed on 3 cats in which treatment had failed. All 3 had severe inflammatory disease of the urinary bladder, but none had evidence of bladder rupture.

Conclusions and Clinical Relevance—Results suggested that in male cats, a combination of pharmacological treatment, decompressive cystocentesis, and a low-stress environment may allow for resolution of UO without the need for urethral catheterization. This low-cost protocol could serve as an alternative to euthanasia when financial constraints prevent more extensive treatment.

Full access
in Journal of the American Veterinary Medical Association

Objective

To compare recurrence of signs of lower urinary tract disease (LUTD) in cats with idiopathic cystitis that were fed the dry or canned formulation of a commercial diet designed to result in production of an acidic urine.

Design

Prospective trial.

Animals

54 client-owned cats with idiopathic cystitis that was diagnosed on the basis of a history of abnormal micturition, abnormal results on urinalysis, radiography, or cystoscopy, and lack of an alternative diagnosis.

Procedure

Cats were assigned to be fed the canned or dry formulation of the diet. Reevaluations conducted at 2 and 16 weeks, and at 6 and 12 months included a physical examination, CBC and serum biochemical analysis (except week 2), blood gas analysis, and urinalysis. Regular telephone contacts were also made. The study was discontinued after 12 months or if signs of LUTD recurred.

Results

Signs of LUTD did not recur in 16 of 18 cats fed the canned diet, and 17 of 28 cats fed the dry diet (χ2, P < 0.05). Seven cats were reevaluated at recurrence. Owners of remaining cats in which signs of LUTD recurred declined to have their pets reexamined. A different problem (bacterial urinary tract infection) was identified in only 1 cat on reevaluation. Eight cats were lost to follow-up evaluation.

Clinical Implications

Feeding this commercial canned urinary acidifying diet may reduce the proportion of cats with idiopathic cystitis that will have recurrence of signs of LUTD within a 12-month period. (J Am Vet Med Assoc 1999;214:361–365)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objectives

To describe changes in renal function of horses after oral and IV administration of sodium bicarbonate (NaHCO3) and to determine whether changes are dose dependent.

Animals

6 Standardbred mares.

Procedure

Blood and urine samples for determination of renal function were collected immediately before and at hourly intervals for 12 hours after administration of each of 3 oral doses (1,500, 1,000, and 250 mg/kg of body weight, in 3 L of water) and 1 IV dose (250 mg/kg, 5% solution) of NaHCO3, or water (3 L orally).

Results

NaHCO3 induced increases in urine flow; electrolyte-free water reabsorption; urine concentrations of sodium and bicarbonate; fractional excretion of sodium, potassium, chloride, and bicarbonate; urinary excretion and clearance of sodium and bicarbonate; urine pH and anion gap; and mean plasma concentration of antidiuretic hormone. NaHCO3 induced attenuation in reduction with time of urine excretion and clearance of potassium, chloride, and osmoles, and induced reduction in urine osmolality. Plasma aldosterone and atrial natriuretic peptide concentrations and glomerular filtration rate were not modified.

Conclusions

Renal responses to NaHCO3 load emphasize conservation of plasma volume and re-establishment of acid-base balance over control of hyperosmolality by means of diuresis, natriuresis, and increased bicarbonaturia. These responses imply a large fluid shift from the extravascular space to the vascular compartment, which was eliminated via diuresis, thus preventing hypervolemia. (Am J Vet Res 1997;58:664–671)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To describe changes in blood constituents of horses after oral and IV administration of sodium bicarbonate (NaHCO3), and to determine whether the changes are dose dependent.

Animals

6 adult Standardbred mares.

Procedure

3 oral doses (1,500, 1,000, and 250 mg/kg of body weight) or 1 intravenous dose (250 mg/kg, 5% solution) of NaHCO3 in 3 L of water, or water (3 L orally), were given to the mares; then changes in blood constituents were measured. Access to food and water was denied during the experiment. Blood samples were collected immediately before treatment and at hourly intervals for 12 hours after treatment, and were analyzed for blood gas tensions; serum osmolality; serum sodium, potassium, chloride, and creatinine concentrations; PCV; and total solids concentration in plasma.

Results

All NaHCO3 treatments induced significant (P < 0.05) metabolic alkalosis, hypernatremia, hypokalemia, and hyperosmolality for at least 8 hours. In mares given the 1,500- and 1,000-mg doses of NaHCO3 orally, hypercapnia persisted for at least 12 hours, whereas hypercapnia lasted 2 hours in mares given the 250-mg dose orally or IV (P < 0.05). A tendency for reduction in PCV, proteins in plasma concentration, and serum concentration of chloride was observed 1 hour after IV administered doses of NaHCO3.

Conclusions

Oral or IV administration of NaHCO3 (≥ 250 mg/kg) to resting horses without ad libitum access to water induces significant and persistent acidbase and electrolyte changes. (Am J Vet Res 1997;58:658–663)

Free access
in American Journal of Veterinary Research

SUMMARY

Urinary indices of renal function and damage were measured in 6 healthy, mature ewes over a 48-hour period. Endogenous creatinine clearance, total and fractional electrolyte excretion rates, protein excretion, urine volume, and urine γ-glutamyltransferase and β-glucuronidase activities were measured. Significant variations in the excretion rates of creatinine, electrolytes, and protein were not found between intervals within the 48-hour urine collection period. Total urinary electrolyte excretion rates were significantly (P < 0.001) correlated with fractional electrolyte excretion rates normalized for creatinine concentration; however, coefficient of determination was low.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine associations between environmental and cat-related factors and lower urinary tract signs in indoor-housed domestic cats.

Design—Case-control study.

Animals—238 healthy cats, 157 cats with clinical signs of lower urinary tract disease, and 70 cats with other diseases.

Procedure—Data collected from owners of the cats were analyzed. Descriptive statistics, environmental variables, and physical and behavioral signs were analyzed by use of ANOVA and logistic regression analysis to assess which factors were associated with clinical signs of lower urinary tract disease.

Results—The only demographic or environmental factors associated with lower urinary tract signs were older age and months owned. In contrast, cats with clinical signs of lower urinary tract disease had significantly greater owner-observed gastrointestinal tract signs and scratching, fearful, nervous, and aggressive behaviors.

Conclusions and Clinical Relevance—Lower urinary tract signs in indoor-housed cats may be more closely associated with cat-related factors than with demographic or environmental factors.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare the effects of propofol and sevoflurane on the urethral pressure profile in female dogs.

Animals—10 healthy female dogs.

Procedure—Urethral pressure profilometry was performed in awake dogs, during anesthesia with sevoflurane at 1.5, 2.0, and 3.0% end-tidal concentration, and during infusion of propofol at rates of 0.4, 0.8, and 1.2 mg/kg/min. A consistent plane of anesthesia was maintained for each anesthetic protocol. Maximum urethral pressure, maximum urethral closure pressure, functional profile length, and functional area were measured.

Results—Mean maximum urethral closure pressure of awake dogs was not significantly different than that of dogs anesthetized with propofol at all infusion rates or with sevoflurane at 1.5 and 2.0% end-tidal concentration. Functional area in awake dogs was significantly higher than in anesthetized dogs. Functional area of dogs during anesthesia with sevoflurane at 3.0% end-tidal concentration was significantly lower than functional area for other anesthetic protocols. Individual differences in the magnitude of effects of propofol and sevoflurane on urethral pressures were observed.

Conclusions and Clinical Relevance—Sevoflurane is an alternative to propofol for anesthesia in female dogs undergoing urethral pressure profilometry. Use of these anesthetics at appropriate administration rates should reliably distinguish normal from abnormal maximum urethral closure pressures and functional areas. Titration of anesthetic depth is a critical component of urodynamic testing. (Am J Vet Res 2003;64:1288–1292)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate in vitro effects of gemcitabine alone and in combination with carboplatin on canine transitional cell carcinoma (TCC) cell lines.

Sample—In vitro cultures of 5 canine TCC cell lines.

Procedures—Cells were treated with gemcitabine, carboplatin, or a combination of both at various concentrations. Cell proliferation was assessed via a fluorescence-based microplate cell proliferation assay. Cell cycle was evaluated via propidium iodide staining, and apoptosis was assessed by measurement of caspase 3 and 7 enzymatic activity. Synergy between gemcitabine and carboplatin was quantified via combination index analyses.

Results—Treatment of 5 canine TCC cell lines with gemcitabine or carboplatin decreased cell proliferation, increased apoptosis, and induced cell cycle arrest. Cell cycle arrest and apoptosis were markedly increased when cell lines were treated with both gemcitabine and carboplatin simultaneously or sequentially. Order of administration during sequential treatment did not consistently affect cell proliferation results in TCC cell lines. When TCC cell lines were treated with gemcitabine and carboplatin in combination at therapeutically relevant concentrations (gemcitabine concentration, < 10μM; carboplatin concentration, < 250μM), a significant decrease in cell proliferation was observed, compared with cell proliferation following treatment with gemcitabine or carboplatin alone. In combination, the effects of gemcitabine and carboplatin were synergistic in 3 of 5 cell lines and additive in the other 2.

Conclusions and Clinical Relevance—Gemcitabine had antitumor effects on canine TCC cells in vitro, and the combination of gemcitabine and carboplatin had synergistic activity at biologically achievable concentrations.

Full access
in American Journal of Veterinary Research