Effects of oral administration of orotic acid on hepatic morphologic characteristics and serum biochemical variables in cats.

OBJECTIVE: To evaluate orotic acid (OA) as a possible etiologic factor in cats with idiopathic hepatic lipidosis (HL). ANIMALS: 20 clinically normal adult female cats. PROCEDURE: Cats were fed a control diet or a diet containing less protein. On day 1 of the control period, blood, urine, and liver biopsy specimens were obtained. Each cat was given an oral dose of water daily. On days 8, 15, and 22, blood and urine specimens were collected as on day 1. On day 29, liver, blood, and urine samples were obtained as on day 1. After a resting period of 30 to 60 days, cats were treated with orotic acid. Serum biochemical analyses, urinary OA-to-creatinine ratios, and liver biopsy specimens were evaluated. Cats were given OA orally (suspension or capsules) for 29 days. Sample collection and data obtained were identical to those described for the control period. RESULTS: Urinary OA-to-creatinine ratios were significantly higher in all treated cats, but ratios were significantly higher in those receiving OA in capsules than in those receiving OA in suspension. Diet or treatment did not alter hepatic biochemical or histologic variables significantly. However, 7 cats given the highest dose of OA in capsules developed azotemia, urolithiasis, and renal changes. CONCLUSIONS: Most concentrations of OA used in this study did not induce HL in cats during a 29-day period, but the highest dosage used did result in renal disease. CLINICAL RELEVANCE: Orotic acid does not appear to be involved in the genesis of HL in cats.     

Measurement of aldosterone in feline, canine and human urine

BACKGROUND: Systemic hypertension is an important problem in older cats associated with kidney disease and hypokalaemia, suggesting that excessive activity of the renin-angiotensin-aldosterone system might contribute to the hypertensive state. Fluctuations in plasma renin activity and plasma aldosterone concentrations complicate the interpretation of these assays. OBJECTIVES: The aim of this study was to determine whether measurement of urinary aldosterone excretion in cats aided the investigation of hypertension. METHODS: Urine concentrations of free (ethyl acetate extract) and 18-glucuronidated aldosterone (acid hydrolysis before extraction) were measured by radioimmunoassay in normal, normotensive and hypertensive azotaemic cats (n=11 per group). Urine samples from 11 healthy human volunteers and eight normal dogs were also analysed for comparison. Urinary aldosterone concentration was corrected for the urinary creatinine concentration. RESULTS: Cats excreted 7.3 times less free aldosterone than human beings, and no free aldosterone was detected in dog urine. Acid hydrolysis led to large increases in aldosterone recovery from both human beings and dog but not feline urine. No significant effect of hypertension or azotaemia on feline urinary aldosterone concentration was found. CLINICAL SIGNIFICANCE: Measurement of aldosterone in feline urine using the available methodology has limited or no utility in investigating feline hypertension.     

Association of urinary cadmium excretion with feline hypertension

Fifty client-owned senior cats (32 normotensive and 18 hypertensive) with renal function ranging from normal to moderately reduced were recruited into a prospective cross-sectional study exploring the association of urinary cadmium excretion and hypertension in cats. Heparinised plasma samples were collected and analysed for routine biochemical parameters. Urine samples were collected via cystocentesis and were analysed for cadmium concentrations using inductively coupled plasma mass spectrometry (ICP-MS). Blood pressure was measured using the Doppler method. Urinary cadmium concentrations were indexed to urinary creatinineconcentration. Comparison of urinary cadmium excretion was made between hypertensive and normotensive cats.The median (range) urinary cadmium concentration standardised to urinary creatinine concentration (UCdCr) in the normotensive and hypertensive cats was 0.08 (0.02 to 0.37) and 0.12 (0.02 to 1.38) nmol/mmol creatinine. The UCdCr was significantly higher in hypertensive compared with normotensive cats (P=0.016). UCdCr and plasma creatinine concentration remained independent predictors of hypertensive status in a logistic regression model. UCdCr and plasma creatinine concentration were not correlated (r=-0.01, P=0.956). These data suggest cadmium exposure and accumulation in cats may play a role in the development of feline hypertension.     

A retrospective study of serum β-hydroxybutyric acid in 215 ill cats: clinical signs, laboratory findings and diagnoses

Serum concentrations of β-hydroxybutyric acid (sBHBA) are increased in cats with diabetes mellitus (DM), diabetic ketoacidosis (DKA) and hepatic lipidosis (HL). This study assessed sBHBA as a diagnostic tool in 215 consecutively-enrolled ill cats in the general population in a veterinary hospital. At the time of presentation, sBHBA was within the reference range in 158/215 (73.5%) cats (median 0.27; range 0.00-0.49 mmol/L) and elevated in 57/215 (26.5%) cats (median 0.87; range 0.51-21.45 mmol/L). Compared to cats with normal sBHBA, those with increased sBHBA had higher frequencies of anorexia, weight loss, icterus, polyuria/polydipsia, hyperbilirubinaemia, hypertriglyceridaemia, pancreatitis, HL, DM and DKA. They had higher concentrations of bilirubin and triglycerides and lower concentrations of potassium, chloride and total protein. There were positive correlations (P<0.01) between sBHBA and urinary glucose (r=0.42) and ketones (r=0.76), but there were no group differences in dipstick levels of urinary ketones. Cats with DM/DKA and with HL had significantly higher sBHBA compared to other cats. Receiver operator characteristics analysis of sBHBA as a predictor of HL showed that sBHBA was a good predictor of HL. Increased sBHBA occurs frequently in ill cats and provides useful diagnostic information, especially in DM/DKA and HL.     

Correlation of Urine Protein/Creatinine Ratio and Twenty-Four-Hour Urinary Protein Excretion in Normal Cats and Cats with Surgically Induced Chronic Renal Failure

Urine protein/creatinine (UP/C) ratios and 24-hour urinary protein excretion were compared in clinically normal cats and cats with surgically induced chronic renal failure (CRF). Mean 24-hour urinary protein excretion in 30 clinically normal cats fed a 28% protein diet (dry weight basis) was 4.93 mg/kg/24-hour (SD = 1.34) with a range of 2.99 to 8.88. Mean UP/C ratio in these cats was 0.134 (SD = 0.037) with a range of 0.073 to 0.239. Mean 24-hour urinary protein excretion in CRF cats was 10.49 mg/kg/24-hour (SD = 11.28) with a range of 2.16 to 62.93. Mean UP/C ratio in the CRF cats was 0.359 (SD = 0.374) with a range of 0.061 to 1.916. Linear regression showed high correlation (R2 = 0.973, P less than 0.001) between 24-hour urinary protein excretion and UP/C ratio in clinically normal cats and cats with surgically induced chronic renal failure. The regression equation for 24-hour urinary protein excretion versus UP/C ratio was: 24-hour urinary protein excretion = 29.39 (UP/C) + 0.18. Results of this study indicate that UP/C ratios are a valid estimate of 24-hour urinary protein excretion in clinically normal and CRF cats. Dietary protein intake significantly affected UP/C ratios in clinically normal cats and cats with surgically induced CRF. Therefore, the influence of dietary protein should be considered when interpreting UP/C ratios.     

Acute Pancreatitis in Cats With Hepatic Lipidosis

The purpose of this study was to characterize the incidence, clinical features, and prognosis of acute pancreatitis in cats with hepatic lipidosis. Of 13 cats histologically diagnosed with hepatic lipidosis between July 1988, and November 1989,5 (38%) were also histologically diagnosed with acute pancreatitis. In cats with hepatic lipidosis alone, the signalment, history, physical examination, and clinicopatho-logic findings were generally indistinguishable from those of cats with concurrent acute pancreatitis except that cats with acute pancreatitis were more likely to be cachectic and to have coagulation abnormalities. Hepatomegaly was seen on abdominal radiographs in both groups. Of the 5 cats with concurrent acute pancreatitis, abdominal ultrasonography detected 1 cat with a hypoechoic pancreas and 5 with peritoneal effusion; those abnormalities were not seen in cats without concurrent acute pancreatitis. Cats with concurrent acute pancreatitis had only a 20% recovery rate, compared with a 50% recovery rate in cats with hepatic lipidosis alone. We conclude that cats with hepatic lipidosis should be rigorously evaluated for concurrent acute pancreatitis because of 1) the rate of disease coincidence, 2) the inability of signalment, history, physical examination, and clinicopathologic findings to adequately distinguish between hepatic lipidosis and acute pancreatitis, 3) the worse prognosis associated with concurrent acute pancreatitis, and 4) the opposing nutritional strategies for hepatic lipidosis and acute pancreatitis. (Journal of Veterinary Internal Medicine 1993; 7:205–209. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Determination of protein concentrations and their molecular weight in tears from cats with normal corneas and cats with corneal sequestrum.

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.     

Susceptibility of bacteria from feline and canine urinary tract infections to doxycycline and tetracycline concentrations attained in urine four hours after oral dosage

OBJECTIVES: To measure urinary concentrations of doxycycline in cats and dogs and tetracycline in dogs 4 h after conventional oral dosing and determine whether these antibiotics were present in sufficient concentrations to be effective against common feline and canine urinary tract pathogens as assessed in vitro by Epsilometer and disc diffusion antimicrobial susceptibility methods. DESIGN: A prospective study involving oral administration to clinically normal cats and dogs of doxycycline or tetracycline (dogs only) and culture of bacteria from dogs and cats with urinary tract infections to determine their susceptibility to both doxycycline and tetracycline in vitro. PROCEDURE: In the first study, nine cats and eight dogs were administered doxycycline monohydrate (5 mg/kg every 12 h) and a further eight dogs were administered tetracycline hydrochloride (20 mg/kg every 8 h) for 72 h. Blood was collected at 2 and 4 h, and urine at 4 h, after the last dose. The concentration of each agent in serum and urine was determined by modified agar diffusion. In the second study, 45 urine samples from cats and dogs with urinary tract infections were cultured. Every bacterial isolate was tested in vitro using both Epsilometer (doxycycline and tetracycline) and disc diffusion (doxycycline, tetracycline or amoxycillin-clavulanate) tests. RESULTS: Serum doxycycline concentrations in sera of cats and dogs at 2 h were 4.2 +/- 1.0 mg/mL and 3.4 +/- 1.1 mg/mL, respectively. The corresponding concentrations at 4 h were 3.5 +/- 0.7 mg/mL and 2.8 +/- 0.6 mg/mL. Urinary doxycycline concentrations at 4 h (53.8 +/- 24.4 mg/mL for cats and 52.4 +/- 24.1 mg/mL for dogs) were substantially higher than corresponding serum values. Serum tetracycline concentrations in dogs at 2 and 4 h, and in urine at 4 h, were 6.8 +/- 2.8, 5.4 +/- 0.8, 144.8 +/- 39.4 mg/mL, respectively. Most of the urinary tract pathogens (35/45) were susceptible to urinary concentrations of doxycycline and 38/45 were susceptible to tetracycline. In contrast 41/45 of all isolates were susceptible to amoxycillin-clavulanate. CONCLUSION: This is the first report of urinary concentrations of doxycycline after conventional oral administration. Concentrations attained in the urine of normal cats and dogs were sufficient to inhibit the growth of a significant number of urinary tract pathogens and thus doxycycline may be a useful antimicrobial agent for some urinary tract infections.     

Metabolic and hormonal alterations in cats with hepatic lipidosis

Hepatic lipidosis in cats is a commonly diagnosed hepatobiliary disease of unknown cause. The purpose of this prospective study was to characterize the blood hormone and lipid status of cats with hepatic lipidosis, and to compare this status to that of cats with other types of liver disease and to control cats. Twenty-three cats with hepatic disease were assigned to 1 of 2 groups on the basis of cytopathologic or histopathologic examination of the liver: group 1, hepatic lipidosis (n = 18); or group 2, cholangiohepatitis (n = 5). Ten healthy young adult cats were used as controls. Food was withheld from control animals for 24 hours before blood collection. Concentrations of plasma glucagon and serum insulin, cortisol, thyroxine, triglycerides, cholesterol, phospholipids, and nonesterified fatty acids (NEFAs) were determined in all cats, in addition to routine hematologic and serum biochemical testing. Cats with hepatic lipidosis had higher serum NEFA concentrations than cats with cholangiohepatitis or control cats (P < .05). Cats with cholangiohepatitis had higher serum cholesterol and phospholipid concentrations than those of cats with lipidosis or control cats (P < .05); their plasma glucagon concentrations were higher than those of control cats (P < .05), but were not different from those of cats with hepatic lipidosis. Serum insulin concentrations were significantly higher in control cats than in diseased cats (P < .05), but neither serum insulin nor the insulin to glucagon ratio was significantly different among the cats with hepatic disease. The high concentration of NEFAs in cats with hepatic lipidosis suggests that at least 1 factor in the pathogenesis of this syndrome may involve the regulation of hormone-sensitive lipase.     

Tubulointerstitial nephritis causes decreased renal expression and urinary excretion of cauxin, a major urinary protein of the domestic cat

Cauxin, a member of mammalian carboxylesterases (EC 3.1.1.1), is excreted as a major urinary protein in the domestic cat. Urinary cauxin is derived from the kidney proximal straight tubules. Here, we report changes in the renal expression and urinary excretion of cauxin in cats with tubulointerstitial nephritis (TIN). Immunohistochemistry using anti-cauxin antibody showed fewer cauxin-positive tubules in 15 TIN cases than in normal animals. In areas with tubulointerstitial damage, fibroblasts and inflammatory cells replaced renal tubules, and cauxin-positive tubules consequently disappeared. Urine was analysed in six of the 15 cases. In the two cases with mild tubulointerstitial changes, urinary cauxin was detected using SDS-PAGE with Coomassie staining. In the four cases with severe tubulointerstitial changes, urinary cauxin was below the detection limit using Western blotting. These results indicate that the renal expression and urinary excretion of cauxin decrease with the progression of TIN in cats.     

Liver glutathione concentrations in dogs and cats with naturally occurring liver disease

OBJECTIVE: To determine total glutathione (GSH) and glutathione disulfide (GSSG) concentrations in liver tissues from dogs and cats with spontaneous liver disease. SAMPLE POPULATION: Liver biopsy specimens from 63 dogs and 20 cats with liver disease and 12 healthy dogs and 15 healthy cats. PROCEDURE: GSH was measured by use of an enzymatic method; GSSG was measured after 2-vinylpyridine extraction of reduced GSH. Concentrations were expressed by use of wet liver weight and concentration of tissue protein and DNA. RESULTS: Disorders included necroinflammatory liver diseases (24 dogs, 10 cats), extrahepatic bile duct obstruction (8 dogs, 3 cats), vacuolar hepatopathy (16 dogs), hepatic lipidosis (4 cats), portosystemic vascular anomalies (15 dogs), and hepatic lymphosarcoma (3 cats). Significantly higher liver GSH and protein concentrations and a lower tissue DNA concentration and ratio of reduced GSH-to-GSSG were found in healthy cats, compared with healthy dogs. Of 63 dogs and 20 cats with liver disease, 22 and 14 had low liver concentrations of GSH (micromol) per gram of tissue; 10 and 10 had low liver concentrations of GSH (nmol) per milligram of tissue protein; and 26 and 18 had low liver concentrations of GSH (nmol) per microgram of tissue DNA, respectively. Low liver tissue concentrations of GSH were found in cats with necroinflammatory liver disease and hepatic lipidosis. Low liver concentrations of GSH per microgram of tissue DNA were found in dogs with necroinflammatory liver disease and cats with necroinflammatory liver disease, extrahepatic bile duct occlusion, and hepatic lipidosis. CONCLUSIONS AND CLINICAL RELEVANCE: Low GSH values are common in necroinflammatory liver disorders, extrahepatic bile duct occlusion, and feline hepatic lipidosis. Cats may have higher risk than dogs for low liver GSH concentrations.     

Refinement of a commercial bench-top relaxin assay for pregnancy diagnosis using urine from domestic and nondomestic felids

Relaxin, a 6-kDa polypeptide hormone, is excreted in the urine during pregnancy in several mammalian species. A recent study showed that detection of urinary relaxin using a bench-top serum assay (Witness relaxin kit, Synbiotics Corp., San Diego, California 92127, USA) can be diagnostic for pregnancy in domestic cats (Felis silvestris catus), but it is unknown whether the bench-top kit is applicable with urine across felid species. Our objectives were to 1) examine modifications in urine processing to improve kit reliability in pregnant cats, 2) evaluate the impact of concentrating urine via filtration on relaxin detection, 3) assess the effect of sample freezing on relaxin concentrations, and 4) begin quantifying urinary relaxin levels in nondomestic felids. Urine and serum were collected from domestic cats and nondomestic cat species (Pallas' cat, Otocolobus manul; sand cat, Felis margarita; cheetah, Acinonyx jubatus; and lion, Panthera leo) at several times after breeding. Urine samples, subjected to various processing methods, were tested using the bench-top kit, and relaxin levels were later quantified via radioimmunoassay. For domestic cat urine samples, filtration and addition of protein/phosphate buffer improved the consistency of the relaxin kit for early pregnancy diagnosis. Urine freezing caused a slight (approximately 13%) but significant decrease in relaxin concentrations, but frozen-thawed samples still tested positive with the bench-top kit. In nondomestic felids, urinary relaxin immunoreactivity during pregnancy was similar to or higher than that of pregnant domestic cats, suggesting that relaxin is a reliable cross-species marker of pregnancy. Urinary relaxin was detectable using the bench-top kit in pregnant Pallas' cats, but urine samples from other species tested negative, regardless of processing methods. Findings suggest that measurement of urinary relaxin is a promising approach for noninvasive pregnancy diagnosis in exotic felids, but further assessment of urinary relaxin profiles among cat species and modification of the bench-top relaxin kit are warranted to improve cross-species utility.     

Concentrations of cartilage oligomeric matrix protein in dogs with naturally developing and experimentally induced arthropathy

OBJECTIVE: To assay concentrations of cartilage oligomeric matrix protein (COMP) in canine sera and synovial fluid (SF), to compare COMP concentrations in clinically normal dogs and dogs with joint disease, and to analyze changes in COMP concentrations in dogs with experimentally induced acute synovitis. ANIMALS: 69 control dogs without joint disease, 23 dogs with naturally occurring aseptic arthropathy, and 6 dogs with experimentally induced synovitis. PROCEDURE: Serum (n = 69) and SF (36) were obtained from control dogs. Samples of serum (n = 23) and SF (13) were obtained from dogs with naturally occurring aseptic arthropathy with or without radiographic features of osteoarthritis (OA). Serum and SF were obtained before and 1, 2, 3, and 7 days after induction of synovitis. The COMP concentrations were determined by use of an inhibition ELISA that had canine cartilage COMP and monoclonal antibody against human COMP. RESULTS: Concentrations of COMP in serum and SF of control dogs were 31.3+/-15.3 and 298.7+/-124.7 microg/ml, respectively. In naturally occurring OA, COMP concentrations in serum (44.9+/-177 microg/ml) and SF (401.7+/-74.3 microg/ml) were significantly higher than corresponding concentrations in control dogs. The COMP concentration in SF peaked 24 and 48 hours after induction of synovitis, whereas concentration in serum peaked on day 3. CONCLUSIONS AND CLINICAL RELEVANCE: These results supported the hypothesis that COMP concentration in serum and SF of dogs may be altered after cartilage degradation or synovitis. Measurement of COMP concentrations can be useful when differentiating arthropathies in dogs.     

Prevalence of the polycystic kidney disease and renal and urinary bladder ultrasonographic abnormalities in Persian and Exotic Shorthair cats in Italy

The ultrasonographic findings of kidneys, liver and urinary bladder of 288 Persian and 44 Exotic Shorthair clinically normal cats that underwent screening for polycystic kidney disease (PKD) between July 2003 and December 2005 were reviewed. Cats were divided into two groups, one including cats aged <9 months (group 1) and one cats aged >/=9 months (group 2). Cats were classified as PKD-positive when at least one renal cyst was found. One hundred and thirty-six cats (41.0%) had more than one cyst in at least one kidney. The prevalence of PKD was similar in both groups. Eight PKD-positive cats had cystic livers (5.9%). Other renal abnormalities included a pelvic calculus and a medullary rim sign (MRS). The difference in prevalence of an MRS in group 2 compared to group 1 and the difference between PKD-positive and -negative cats in group 2 were not significant. There was no difference in mean kidney length between PKD-positive and -negative cats in group 2. Urinary bladder anomalies were principally represented by urinary sediment, with prevalence significantly higher in group 2. No difference was detected in group 2 between PKD-positive and -negative cats. In conclusion feline PKD is common in Italy. The ultrasonographic findings of MRS and urinary bladder sediment did not correlate with feline PKD. Urinary bladder sediment is common in Persians and Exotic Shorthairs and more likely in adults.     

Hepatic Lipidosis in Anorectic, Lactating Holstein Cattle: A Retrospective Study of Serum Biochemical Abnormalities

The association between hepatic lipidosis (HL) and disease in 59 anorectic, ketotic, lactating Holstein heifers and cows was investigated. Severe HL, as determined by histologic evaluation of liver tissue, was present in 46 animals; only half of these animals required intensive treatment for ketosis, and only half had serum biochemical evidence of liver disease, as determined by the presence of a test value of 2-fold or greater than the upper limit of the reference range for at least 2 of the 4 serum tests: gamma-glutamyl transferase, aspartate aminotransferase, and sorbitol dehydrogenase activities and bile acid concentrations. Most cattle with biochemical evidence of liver disease and severe HL had been lactating for 14 or more days. Cows that required intensive treatment inconsistently had serum biochemical evidence of liver disease.
Although cattle with severe HL had significantly higher serum bilirubin concentrations and aspartate aminotransferase and sorbitol dehydrogenase activities than cattle with less severe lipidosis, the specificity of abnormally high serum sorbitol dehydrogenase activity or bilirubin concentration for severe lipidosis was only 8%. Abnormally high serum aspartate aminotransferase activity was 83% sensitive and 62% specific for severe lipidosis. Serum glucose and total carbon dioxide concentrations were significantly lower in cattle with severe lipidosis than in those with mild or moderate lipidosis, and low serum glucose or total carbon dioxide concentrations were rare in cattle without severe lipidosis. From these data, we conclude that the use of a single biochemical or histopathologic criterion to define severity of disease or degree of liver compromise in anorectic, ketotic cows results in the misidentification of many animals.     

Occurrence of occult bacteriuria in healthy cats

Knowledge of the occurrence of bacteriuria in adult, healthy cats is scarce in the scientific literature. A study was designed to investigate the occurrence of bacteriuria in healthy cats without current or previous signs of lower urinary tract disease. The study included 108 cats, 53 males (49.5%) and 55 females (50.5%). The cats ranged in age between 7 months and 18 years, with a mean age of 4.4 years and a median age of 4.0 years. Urine was obtained by cystocentesis from all the cats, and was submitted for bacteriological analyses. Urine and urine sediment was cultured on separate blood agar plates for quantification and species identification by standard procedures. Detection of ≥10(3)colony forming units (cfu) per ml urine was defined as significant bacteriuria. Significant bacteriuria exceeding 10(5) cfu/ml was detected in one sample with a combination of Enterococcus species and Staphylococcus species. There was no bacterial growth in the urine samples from 107 cats (99.1%). Results from our study indicate that the prevalence of bacteriuria in clinically healthy, adult cats is low. Also, that contamination of samples is rare when urine is collected by cystocentesis.     

Frequency and risk factors for urinary tract infection in cats with diabetes mellitus

BACKGROUND: Identification and control of infections are important in the management of diabetic cats. Urinary tract infections have not been well characterized in diabetic cats. This retrospective study was performed to review and characterize urinary tract infections in diabetic cats. HYPOTHESIS: Urinary tract infections are common in diabetic cats. ANIMALS: A review was made of the medical records of 141 diabetic cats that had had urine obtained for culture by antepubic cystocentesis and that had not been treated with antibiotics, undergone urinary tract catheterization or urinary tract surgery within 2 weeks of urine collection or had urethral obstruction at the time of urine collection. METHODS: A review of medical records. RESULTS: Urinary tract infection was identified in 18 of 141 diabetic cats. Escherichia coli was the most common isolate (67%). Female cats were at increased risk (prevalence odds ratios [POR], 3.7; 95% confidence interval [CI], 1.3 to 10.2; P = .013). Clinical signs of lower urinary tract disease and findings on urine sediment examination were good predictors of positive urine cultures. CONCLUSIONS AND CLINICAL IMPORTANCE: Urinary tract infections are common in diabetic cats regardless of status of diabetic control, suggesting routine monitoring with urine sediment exams or urine culture is warranted.     

Cardiopulmonary evaluation of the use of medetomidine hydrochloride in cats.

OBJECTIVE: To evaluate the cardiovascular effects of the alpha2-adrenergic receptor agonist medetomidine hydrochloride in clinically normal cats. ANIMALS: 7 clinically normal cats. PROCEDURE: Cats were anesthetized with isoflurane, and thermodilution catheters were placed for measurement of central venous, pulmonary, and pulmonary capillary wedge pressures and for determination of cardiac output. The dorsal pedal artery was catheterized for measurement of arterial blood pressures and blood gas tensions. Baseline variables were recorded, and medetomidine (20 microg/kg of body weight, IM) was administered. Hemodynamic measurements were repeated 15 and 30 minutes after medetomidine administration. RESULTS: Heart rate, cardiac index, stroke index, rate-pressure product, and right and left ventricular stroke work index significantly decreased from baseline after medetomidine administration, whereas systemic vascular resistance and central venous pressure increased. However, systolic, mean, and diastolic arterial pressures as well as arterial pH, and oxygen and carbon dioxide tensions were not significantly different from baseline values. CONCLUSIONS AND CLINICAL RELEVANCE: When administered alone to clinically normal cats, medetomidine (20 microg/kg, IM) induced a significant decrease in cardiac output, stroke volume, and heart rate. Arterial blood pressures did not increase, which may reflect a predominant central alpha2-adrenergic effect over peripheral vascular effects.     

Serum amyloid A protein concentration measured by radial immunodiffusion in Abyssinian and non-Abyssinian cats

Serum amyloid A (SAA) protein concentration was determined by use of radial immunodiffusion (RID) in 4 groups of cats: Abyssinian cats with amyloidosis, healthy Abyssinian cats without clinical evidence of amyloidosis, hospitalized non-Abyssinian cats, and clinically normal non-Abyssinian cats. Mean SAA concentration in Abyssinian cats with amyloidosis was significantly (P = 0.05) higher than mean SAA concentration in healthy Abyssinian cats without clinical evidence of amyloidosis and in hospitalized non-Abyssinian cats. Mean SAA concentration in clinically normal non-Abyssinian cats was significantly (P = 0.05) lower than mean SAA concentration in healthy Abyssinian cats without clinical evidence of amyloidosis and in hospitalized non-Abyssinian cats. Affected and healthy Abyssinian cats, however, could not reliably be distinguished on the basis of SAA concentration, because of the wide range of SAA values in these 2 groups of cats.     

Comparison of fractional excretion and 24-hour urinary excretion of sodium and potassium in clinically normal cats and cats with induced chronic renal failure.

The influence of induced chronic renal failure on 24-hour urinary excretion and fractional excretion of sodium and potassium was studied in cats. Induction of chronic renal failure significantly increased fractional excretion of potassium (P less than 0.0001) and sodium (P less than 0.05); however, 24-hour urinary excretion of sodium and potassium decreased slightly following induction of chronic renal failure. Fractional excretion and 24-hour urinary excretion of sodium and potassium were compared by linear regression in clinically normal cats, cats with chronic renal failure, and clinically normal and affected cats combined. In clinically normal cats, linear regression revealed only moderate correlation between fractional excretion and 24-hour urinary excretion for sodium and potassium. Linear regression of these same relationships in cats with chronic renal failure, and in clinically normal cats and cats with chronic renal failure combined, indicated low correlation. Fractional excretions of sodium and potassium were not reliable indicators of 24-hour urinary excretion of these electrolytes in cats with chronic renal failure or unknown glomerular filtration rate. Fractional excretion of potassium and sodium correlated only moderately with 24-hour urinary excretion in clinically normal cats.