Creatinine concentration in plasma from dog, rat, and mouse: a comparison of 3 different methods

BACKGROUND: There are numerous methods for analyzing creatinine concentration in plasma, including the Jaffé alkaline picrate method in various modifications, enzymatic tests, and chromatographic methods. OBJECTIVE: The purpose of this study was to evaluate whether an enzymatic method could replace a Jaffé method for routine creatinine measurements in plasma from dogs, rats, and mice. The enzymatic method and a compensated Jaffé method were tested against a high-pressure liquid chromatography (HPLC) method, regarded as the gold standard for creatinine measurement. METHODS: Heparinized plasma samples were obtained from 20 beagle dogs, 20 Wistar rats, and 20 CD1-strain mice. The 2 test kits (Roche Diagnostics), Creatinine Jaffé Compensated and the enzymatic Creatinine Plus Version 2 reagent, were used on a Cobas Integra 400. The Jaffé compensated method used a calibration adjustment of 18 micromol/L to correct for the protein matrix in serum and plasma. The HPLC method was an isocratic method using a weak cation-exchange column following protein precipitation. RESULTS: Creatinine concentrations obtained using the enzymatic and the Jaffé methods differed significantly from the results obtained by the HPLC method. For dog plasma, mean values of 61.2, 61.8, and 67.8 micromol/L were obtained by the compensated Jaffé, enzymatic and HPLC methods, respectively. In the rat, respective mean values were 26.7, 21.9, and 23.0 micromol/L, and in the mouse, respective mean values were 14.2, 5.4, and 9.2 micromol/L. CONCLUSION: The enzymatic method can replace the Jaffé method for plasma creatinine determination in dogs, rats, and mice because results from the enzymatic method were closer to HPLC values than were those of the Jaffé method.     

Inaccuracy of routine creatinine measurement in canine urine

BACKGROUND: Urine creatinine concentration often is used in ratios such as urine protein:creatinine to compensate for dilution or concentration of spot urine samples. OBJECTIVE: The purpose of this study was to compare the accuracy of different techniques of urine creatinine measurement currently available for veterinary practitioners. METHODS: In 104 samples of canine urine diluted 1:20 with distilled water, creatinine concentration was measured using a kinetic Jaffé reaction assay, and an enzymatic technique on an automatic analyzer (Elimat) and 3 benchtop analyzers (Reflovet, Scil; Vitros DT2, Ortho-Clinical Diagnostics; Vettest 8008, IDEXX) used in veterinary practice. RESULTS: The Jaffé and enzymatic techniques on the Elimat were not significantly different, and their inaccuracy tested with human control urines was <5%. The benchtop analyzers underestimated creatinine concentration, especially at concentrations >2000 mg/L. Inaccuracy was higher with multilayer slide technology systems (Vitros and Vettest) than with the Reflovet system. Results were approximately 25% and 2% lower, respectively, than with the Elimat at urine creatinine concentrations about 2000 mg/L. CONCLUSION: Inaccuracy in urine creatinine measurements using benchtop analyzers should be taken into account when defining decision thresholds, which should be corrected according to the method used to avoid misinterpretations.     

Disposition of plasma creatinine in non-azotaemic and moderately azotaemic cats

The objectives of this study were to compare assay methods for plasma creatinine (Pl-creat) in cats and to describe the disposition of creatinine and iohexol in 12 healthy and moderately azotaemic cats. Exogenous creatinine and iohexol were injected simultaneously by intravenous bolus, and repeated blood samples were taken to determine the pharmacokinetic parameters of each marker. Pl-creat was assayed by high-performance liquid chromatography (HPLC), Jaffé and enzymatic methods. The enzymatic method was shown to be more reliable than the Jaffé method. Two stereoisomers, exo- and endo-iohexol were identified. The plasma clearance of creatinine (2.3+/-0.66 ml/min/kg) was significantly higher (P<0.001) than that of exo-iohexol (1.7+/-0.40 ml/min/kg). The volume of distribution (447+/-97 ml/kg) and elimination half-life (181+/-77 min) of creatinine were also higher (P<0.001) than those of exo- and endo-iohexol. The estimated daily endogenous production of creatinine was 65+/-23 mg/kg. None of the pharmacokinetic parameters was changed by the azotaemic status of the animals.     

Effects of heparin, citrate, and EDTA on plasma biochemistry of sheep: Comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals, but limited information is existing for sheep plasma biochemistry. Ten clinically healthy Baloochi breed of sheep were blood sampled in different tubes containing each anticoagulants and plain tube for harvesting plasma and serum. The concentrations of glucose, cholesterol, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, and magnesium and the activity of aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of GGT, bilirubin and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than that of serum. For corrected citrated plasma significant differences were seen for the concentrations of glucose, creatinine, calcium and the activity of ALP.Most parameters did not show any difference, but significant increase was seen for albumin concentration when heparin was used as an anticoagulant. Using EDTA as anticoagulant caused a significant difference for the concentrations of some of the measured parameters in plasma except glucose, GGT, cholesterol, albumin, bilirubin, CK, and inorganic phosphorus comparing with serum.     

Effects of aminoglycoside antibiotics on renal antioxidants, malondialdehyde levels, and some serum biochemical parameters

Effects of amikacin, gentamicin, kanamycin, and streptomycin on renal tissue superoxide dismutase, glutathione peroxidase, glutathione and malondialdehyde, serum creatinine, potassium, sodium, total protein, glucose, uric acid, and total bilirubin levels were investigated. All aminoglycoside antibiotics decreased renal tissue glutathione levels.     

Seroprevalence of Borrelia burgdorferi-Specific C6 Antibody in Dogs Before and After Implementation of a Nonadjuvanted Recombinant Outer Surface Protein A Vaccine in a Rhode Island Small Animal Clinic

The in vitro activity of 10 cephalosporin antimicrobial agents against 75 isolates of methicillin-susceptible Staphylococcus pseudintermedius derived from dogs was assessed. The lowest minimal inhibitory concentration for 90% of strains (MIC90) values obtained were for cephalothin, cefovecin, and cefazolin (0.12 ug/mL), followed by ceftiofur and cefoxitin (0.25 ug/mL), cefpodoxime (0.5 ug/mL), and cefaclor and cefadroxil (1 ug/mL). The highest MIC90 values were found for cephalexin and cefixime (2 ug/mL). In this in vitro study, sensitivity to cephalothin was indicative of cephalexin susceptibility, although there were marked differences in MICs. Cephalothin susceptibility was not indicative of susceptibility to all tested cephalosporins, nor was there a clear trend in susceptibility based on cephalosporin generation.     

CERTAIN HEMATOLOGIC AND BLOOD CHEMICAL VALUES IN JUVENILE RHESUS MONKEYS (MACACA MULATTA)

Certain hematologic and clinical chemistry values of 148 rhesus monkeys were determined. Mean values, standard deviations and minimal-maximal values were determined for hemoglobin concentration and packed cell volume; total erythrocyte, total leukocyte and differential leukocyte count; cellular indices; prothrombin time; serum concentrations of glucose, urea nitrogen, uric acid, bilirubin, creatinine, sodium, potassium and chloride, and serum enzyme activities of alkaline phosphatase, glutamic pyruvic transaminase, glutamic oxalacetic transaminase, and lactic dehydrogenase. Calculations were made separately for males and females and the data were compared to published values for the species.     

The effects of sodium ampicillin, sodium cefazolin, and sodium cefoxitin on blood pressures and heart rates in healthy, anesthetized dogs

This study determined the effects of intravenous ampicillin, cefazolin, and cefoxitin on blood pressures and heart rates in healthy, anesthetized dogs. Forty dogs were each randomly assigned to a control, ampicillin, cefazolin, or cefoxitin group. Antibiotics or saline was delivered by intravenous bolus prior to surgical stimulation. Heart rate; systolic, mean, and diastolic arterial pressures; oxygen saturation; end-tidal halothane; and end-tidal carbon dioxide (CO2) were recorded before and every minute for 10 minutes after the test drug was administered. No significant differences were recorded between the antibiotic and control groups. The prophylactic use of these antibiotics should be considered safe in healthy, anesthetized dogs.     

Clinical evaluation of ketone bodies in body fluids of cows in late pregnancy and their fetuses

Ketone body concentrations were determined in six body fluids of cows in late pregnancy and their fetuses (blood plasma and urine of cows, amniotic and allantoic fetal fluids, and fetal blood serum and urine) using the head-space gas chromatographic method. Physiological ratios O/T% of oxidized (acetone and acetoacetic acid) to total (acetone, isopropanol, acetoacetic and 3-hydroxybutyric acid) ketone bodies were below 10% in cow blood plasma and urine, fetal serum and urine, and allantoic fluid, and below 20% in amniotic fluid. A scheme for the evaluation of the degree and duration of ketosis based on the O/T% ratio is proposed. The existence of a renal regulatory mechanism for excretion of ketone bodies is suggested by analogy with the renal acidobasic regulation.     

Clinical evaluation of ketone bodies in body fluids of cows in late pregancy and their fetuses

Ketone body concentrations were determined in six body fluids of cows in late pregnancy and their fetuses (blood plasma and urine of cows, amniotic and allantoic fetal fluids, and fetal blood serum and urine) using the head-space gas chromatographic method. Physiological ratios 0/T% of oxidized (acetone and acetoacetic acid) to total (acetone, isopropanol, acetoacetic and 3-hydroxybutyric acids) ketone bodies were below 10% in cow blood plasma and urine, fetal serum and urine, and allantoic fluid, and below 20% in amniotic fluid. A scheme for the evaluation of the degree and duration of ketosis based on the 0/T% ratio is proposed. The existence of a renal regulatory mechanism for excretion of ketone bodies is suggested by analogy with the renal acidobasic regulation.     

Effects of bilirubinemia, hemolysis, and lipemia on clinical chemistry analytes in bovine, canine, equine, and feline sera

Interferences caused by bilirubin, hemolysis, and lipemia on 25 clinical chemistry analytes in bovine, canine, equine, and feline sera were studied using the Coulter Dacos and commercial reagents. We present the data as “interferograms”, which show the anticipated percent change in serum analyte activity or concentration with varying concentrations of bilirubin, hemoglobin, or lipid. Obvious species differences in response to at least one added interfering substance were found for alanine aminotransferase, aspartate aminotransferase, cholesterol, creatine kinase, globulin, total protein, and urea. The remaining analytes were affected in a linear or complex dose-response relationship or were only affected at the highest concentrations of interfering substances. These data will be useful in aiding interpretation of laboratory test results when common interferences are present in the serum.     

Assessment of the influence of fatty acids on indices of insulin sensitivity and myocellular lipid content by use of magnetic resonance spectroscopy in cats

OBJECTIVE: To determine whether dietary fatty acids affect indicators of insulin sensitivity, plasma insulin and lipid concentrations, and lipid accumulation in muscle cells in lean and obese cats. ANIMALS: 28 neutered adult cats. PROCEDURE: IV glucose tolerance tests and magnetic resonance imaging were performed before (lean phase) and after 21 weeks of ad libitum intake of either a diet high in omega-3 polyunsaturated fatty acids (3-PUFAs; n = 14) or high in saturated fatty acids (SFAs; 14). RESULTS: Compared with the lean phase, ad libitum food intake resulted in increased weight, body mass index, girth, and percentage fat in both groups. Baseline plasma glucose or insulin concentrations and glucose area under the curve (AUC) were unaffected by diet. Insulin AUC values for obese and lean cats fed 3-PUFAs did not differ, but values were higher in obese cats fed SFAs, compared with values for lean cats fed SFAs and obese cats fed 3-PUFAs. Nineteen cats that became glucose intolerant when obese had altered insulin secretion and decreased glucose clearance when lean. Plasma cholesterol, triglyceride, and non-esterified fatty acid concentrations were unaffected by diet. Ad libitum intake of either diet resulted in an increase in both intra- and extramyocellular lipid. Obese cats fed SFAs had higher glycosylated hemoglobin concentration than obese cats fed 3-PUFAs. CONCLUSION AND CLINICAL RELEVANCE: In obese cats, a diet high in 3-PUFAs appeared to improve long-term glucose control and decrease plasma insulin concentration. Obesity resulted in intra- and extramyocellular lipid accumulations (regardless of diet) that likely modulate insulin sensitivity.     

Pharmacokinetics of ceftiofur and metabolites after single intravenous and intramuscular administration and multiple intramuscular administrations of ceftiofur sodium to dairy goats

Twelve (12) lactating dairy goats (46–71 kg body wt at study initiation) were divided into four treatment groups and dosed with ceftiofur sodium at 1.1 mg ceftiofur free acid equivalents (CFAE)/kg or 2.2 CFAE/kg using a complete two route (intravenous, i.v.; intramuscular, i.m.), two-period crossover design, with a 2-week washout between injections. After another 2-week washout period, the goats were dosed with ceftiofur sodium i.m. for 5 consecutive days at either 1.1 or 2.2 mg CFAE/kg. The goats from the 2.2 mg/kg multiple dose group were dried off and the i.v. kinetic study repeated. After all injections, blood samples were obtained serially for determination of combined serum concentrations of ceftiofur and metabolites. After intravenous doses of 1.1 and 2.2 mg/kg, the harmonic means of the terminal phase half-lives were 171.8 and 233 min, respectively, for lactating does. The harmonic mean of the terminal phase half-life after an i.v. dose of 2.2 mg/kg in non-lactating does was 254 min. The AUC _0–∞ was significantly less and the clearance significantly greater during lactation. After i.m. doses of 1.1 and 2.2 mg/kg, the harmonic mean terminal phase half-lives were 163 and 156 min, respectively. The i.m. bioavailability of ceftiofur sodium in goats was 100%, and the AUC _0–∞ was dose-proportional from 1.1–2.2 mg CFAE/kg body weight. After five daily i.m. doses of ceftiofur sodium at either 1.1 or 2.2 mg CFAE, there was minimal accumulation of drug in serum as assessed by C _max, and serum concentrations were dose-proportional after the multiple dosing regimen.     

Are urea and creatinine values reliable indicators of azotaemia in canine babesiosis?

Serum urea and creatinine are extensively used as parameters to screen for azotaemia. Their reciprocal plots roughly correlate with glomerular filtration rate (GFR). They are, however, subject to influence by non-renal factors and to increase their specificity they are often tested concurrently. In renal disease they are expected to behave similarly, with both parameters increasing as GFR decreases. Haemolysis, as it occurs in canine babesiosis, may cause non-renal elevations in serum urea, possibly due to ammonia loading. Furthermore, haemolysis with its related elevations in serum bilirubin and serum haemoglobin, may negatively bias the measurement of serum creatinine due to interference of these substances with the chemical analysis of serum creatinine. This negative bias occurs when the alkaline picrate method, or when direct enzymatic methods based on the measurement of hydrogen peroxide, are used. In order to investigate the significance of these perturbations in canine babesiosis, paired values of serum urea and serum creatinine from Babesia canis-negative, non-haemolysis dogs (Group 1), were used to establish a relationship between urea and creatinine over a range of azotaemia by linear regression analysis. This relationship was then used to predict serum creatinine values from actual serum urea values in B. canis-positive dogs (Group 2). The mean of the predicted serum creatinine values for Group 2 (237.03 micromol/l) was then compared with the mean of the actual serum creatinine values for Group 2 (131.31 micromol/l). For Group 2, the mean actual serum creatinine demonstrated a significant negative bias relative to the mean predicted creatinine value. There was also a higher correlation between serum urea and serum creatinine in Group 1 than in Group 2. These findings may have been caused by either nonrenal elevations of serum urea values or by interference with the measurement of serum creatinine. Therefore, although it is possible that some Group 2 dogs with B. canis with high serum urea and normal, low, or zero values for serum creatinine were not azotaemic, it is also possible that other Group 2 dogs with these biochemical findings did in fact have azotaemia. This study concluded that urea and creatinine do not behave in a similar and predictable manner over a range of azotaemia in canine babesiosis and are therefore not ideally suited for the detection of renal disease in this clinical setting.     

血红素的应用与提取方法

血红素是血红蛋白、肌红蛋白等的辅基,具有重要的生理功能,在医药、食品等方面得到广泛应用。论文介绍了血红素的冰醋酸提取法,酸性丙酮提取法、羧甲基纤维素提取法、酶解提取法、血粉提取法、有机酸和有机碱混合提取法。     

Plasma biochemistry of one-humped camel (Camelus dromedarius): Effects of anticoagulants and comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals but limited informations are existing for camel plasma biochemistry. Eleven clinically healthy one-humped camels were blood sampled in different tubes containing different anticoagulants and plain tubes for harvesting plasma and serum. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium, and chloride and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of AST, ALT, CK, total bilirubin, and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than in serum. Most parameters did not show any difference, but significant increase for CK activity and significant decrease for GGT, cholesterol, creatinine and chloride were seen when heparin was used as anticoagulant. Using EDTA as an anticoagulant caused a significant difference in the amounts of some measured parameters in plasma except glucose, AST, ALT, GGT, cholesterol, albumin, total protein, bilirubin, and triglyceride in comparison with serum.     

Plasma biochemistry of one-humped camel (Camelus dromedarius): effects of anticoagulants and comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals but limited informations are existing for camel plasma biochemistry. Eleven clinically healthy one-humped camels were blood sampled in different tubes containing different anticoagulants and plain tubes for harvesting plasma and serum. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium, and chloride and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of AST, ALT, CK, total bilirubin, and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than in serum. Most parameters did not show any difference, but significant increase for CK activity and significant decrease for GGT, cholesterol, creatinine and chloride were seen when heparin was used as anticoagulant. Using EDTA as an anticoagulant caused a significant difference in the amounts of some measured parameters in plasma except glucose, AST, ALT, GGT, cholesterol, albumin, total protein, bilirubin, and triglyceride in comparison with serum.     

Effects of hemolysis, lipemia, hyperbilirrubinemia, and anticoagulants in canine C-reactive protein, serum amyloid A, and ceruloplasmin assays

The objective of the present study was to determine the effects that hemolysis, lipemia, bilirubinemia, and anticoagulants might have on the most commonly used assays for C-reactive protein and serum amyloid A, and determination of ceruloplasmin values in dogs. Solutions of hemoglobin, lipid, and bilirubin were added to serum aliquots. Additionally, serum and plasma samples with different anticoagulants (heparin, EDTA, and citrate) were obtained from healthy dogs. Hemolysis, lipemia, and hyperbilirubinemia interfered significantly with the C-reactive protein and ceruloplasmin results, but not with those for the serum amyloid A assay. The use of anticoagulants produced significant changes in the results for the assays tested. However, the magnitude of the differences caused by the interfering substances does not appear to have an important impact on the clinical interpretation of the tests.     

Comparison of measurements of canine plasma creatinine, glucose, proteins, urea, alanine aminotransferase, and alkaline phosphatase obtained with Spotchem SP 4430 and Vitros 250 analyzers

The suitability of the Spotchem 4430 benchtop biochemistry analyzer for canine blood samples was tested for creatinine, glucose, proteins, urea, alkaline phosphatases and alanine aminotransferase. Results obtained from whole blood and corresponding heparin plasma were identical except for proteins which were higher in plasma (n=10). Between series imprecision (n=10) was <5% for substrates and <10% for enzymes. Comparison of results from 100 Li-heparin samples with those measured with a Vitros 250 analyzer showed good correlation (r>0.93). The slopes of the Passing-Bablock's regression ranged from 0.90 to 1.20 and intercepts were low. The mean biases were low, except for creatinine for which the results obtained by Spotchem (Jaffe reaction) were about 20 micromol/L higher than with the Vitros (enzymatic reaction). The results of this study show that the Spotchem analyzer is suitable for use in canine whole blood or plasma when small numbers of tests are to be performed and large analyzers are not available.     

Hematology and Clinical Chemistry in Amiata Donkey Foals from Birth to 2 Months of Age

The aim of the present study was to fill the void in data related to hematological and biochemical parameters of donkey foals. Whole-blood and plasma samples were obtained from 16 Amiata donkey foals at birth, at 24 and 48 hours, and at 1, 2, 3, 4, 6, and 8 weeks of age. RBC, WBC, hemoglobin concentration (Hgb), mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelet count, glucose, creatinine, blood urea, triglycerides, total cholesterol, total bilirubin, aspartate aminotransferase, γ-glutamyl transferase, creatine-phosphokinase, alkaline phosphatase, total calcium, potassium, sodium, phosphorus, and albumin were measured. Similar to equine foals, values of RBC, Hgb, and Hct decreased significantly after the first 48 hours of life in Amiata donkey foals, reaching values similar to adult donkeys. No changes were found for mean corpuscular volume and mean corpuscular hemoglobin concentration during the study period. The WBC was low at birth when compared with subsequent measurements, but significantly increased in the subsequent surveys. Platelet count was lower in the first week, with a secondary peak 2 weeks later, and then a decline again up to the eighth week. In agreement with equine foals, electrolyte concentrations, triglycerides, and total cholesterol did not show significant differences. Creatinine, total bilirubin, and blood urea showed a trend similar to RBC, Hgb, and Hct. For the first time, data of hematological and biochemical parameters in Amiata donkey foals are provided.