The evaluation of postmortem ocular fluid analysis as a diagnostic aid in sows

This study was undertaken to evaluate the diagnostic usefulness of postmortem ocular fluid analysis in estimating the antemortem status of various serochemical constituents. Chemical values of serum and aqueous and vitreous humors were compared following different procedures. A blood sample and the 2 eyes were collected from each of 100 sows at a nearby abattoir. The results obtained from immediate centrifugation of ocular fluids after sampling were compared with those samples in which centrifugation was delayed by 2 hours. Two different postmortem intervals were used for sampling ocular fluids, 2 and 24 hours. Concentrations of urea, calcium, phosphorus, potassium, sodium, and chloride were determined from serum and humors. Delayed centrifugation did not affect chemical values of ocular fluids nor the relationships between serum and humors. Phosphorus and potassium values increased significantly with the postmortem interval in both aqueous and vitreous humors. The relationships between chemical values of ocular fluids and serum were determined using simple linear regression. There was a poor correlation between ocular fluid and serum values for all electrolytes; a significant correlation was found only for urea concentrations in both humors.     

Estimation of antemortem serum electrolytes and urea concentrations from vitreous humor collected postmortem.

Electrolyte and urea levels of vitreous humor collected from bovine eyes at various times postmortem, were compared with serum levels in the same animals. Provided the vitreous humor was filtered immediately after collection, measured levels of total calcium (Ca), potassium ions (K+), sodium ions (Na+) and urea nitrogen were very consistent. For 24 hours postmortem the concentrations of Ca, Na+ and urea nitrogen remained stable, while K+ increased to approximately 55% more than the immediate postmortem level. A small study using anesthetized dogs indicated that urea nitrogen levels of vitreous humor take several hours to equilibrate with elevated blood levels. Analysis of vitreous humor may be a useful adjunct to diagnosis in cases where antemortem clinical chemistry is absent or inadequate.     

Postmortem magnesium concentration in bovine vitreous humor: comparison with antemortem serum magnesium concentration

The range for postmortem vitreous humor Mg2+ concentration in 97 healthy cattle was 1.8 mg/dl to 2.72 mg/dl at 23 C for a 48-hour postmortem interval. The postmortem vitreous Mg2+ concentration closely paralleled the antemortem serum Mg2+ concentration at 23 C. Low environmental temperature (4 C) had no effect on postmortem vitreous concentration. However, high environmental temperatures (30 C) significantly (P less than 0.05) reduced postmortem vitreous Mg2+ concentration at the 36-hour postmortem interval. It was concluded that postmortem vitreous humor Mg2+ determination could be a useful diagnostic aid in cattle for detecting Mg2+ imbalances for at least 48 hours after death, provided the postmortem environmental temperature did not exceed 23 C after 24 hours.     

Changes in urea nitrogen and creatinine concentrations in the vitreous humor of cattle after death

The mean urea nitrogen concentration in vitreous humor (VUN) in 97 healthy steers after death was 15.7 mg/dl. The mean serum urea nitrogen concentration in the same cattle was 20.0 mg/dl. The mean vitreous creatinine (VC) concentration was 0.7 mg/dl, and the serum creatinine value was 1.5 mg/dl. The VUN and VC were both significantly lower than serum urea nitrogen and serum creatinine, respectively, but varied in a consistent, predictable manner. In tests with 10 cows, postmortem intervals as long as 36 hours and ambient temperatures up to 30 C had no significant effects on VUN and VC. Evaluation of 8 animals with uremia confirmed that the vitreous humor is a stable fluid compartment after death, usable as an indicator of serum urea nitrogen and creatinine.     

Changes in vitreous humor associated with postmortem interval in rabbits.

Concentrations of serum and vitreous humor constituents at time of death, and concentrations of vitreous humor constituents at time of death and at 7 postmortem intervals were compared in 70 domestic, female New Zealand White rabbits (Oryctolagus cuniculus). Urea nitrogen concentration was significantly (P = 0.0094) different, but was linearly correlated in serum and vitreous humor at time of death and at the 4- and 8-hour postmortem intervals. Concentrations of gamma-glutamyltransferase were not significantly different in serum and vitreous humor at time of death, nor were concentrations significantly different in vitreous humor at time of death and at the 4-hour postmortem interval. The vitreous humor concentrations of glucose, triglycerides, sodium, potassium, cholesterol, total protein, albumin, lactate dehydrogenase, creatine kinase, aspartate transaminase, bilirubin, cortisol, and IgG were neither similar to nor predictive of serum constituents. Vitreous humor can be used as a source for estimates of serum urea nitrogen and gamma-glutamyltransferase up to 8 and 4 hours after death, respectively.     

Chemical analysis of bovine and porcine vitreous humors: correlation of normal values with serum chemical values and changes with time and temperature

Vitreous humors collected from cattle and swine at time of death were compared with serum samples collected before these animals were slaughtered to determine whether vitreous chemical constituents were stable after death occurred. Vitreous humor from 1 eye and serum were obtained from each of 120 cattle and 120 swine at slaughter. The second eye from each animal was enucleated and incubated at 4 C, 20 C, and 37 C for 6, 12, 24, and 48 hours, and then vitreous humor was obtained from the incubated eye. Serum and the fresh and incubated vitreous samples were analyzed for urea nitrogen, creatinine, sodium, potassium, calcium, magnesium, chloride, and phosphorus concentrations. In the incubated vitreous sample, stability varied for urea nitrogen, creatinine, sodium, calcium, magnesium, and chloride concentrations, but the values were generally more stable with samples incubated at lower temperatures and for shorter incubation periods. Potassium and phosphorus concentrations increased with time and temperature of incubation of the samples.     

Haematological and serum biochemical values of southern chamois (Rupicapra pyrenaica)

Blood samples were taken from 75 free-ranging southern chamois (Rupicapra pyrenaica) captured in drive-nets in Catalonia, north-eastern Spain, and 20 haematological and 24 serum biochemical variables were analysed. The values were similar to those of other species of the Caprinae subfamily, except for cortisol, the concentration of which was higher. The red blood cell count (RBC), platelets and leucocytes, and the concentrations of cortisol, lactate, muscular enzymes and gamma-globulins were higher in summer than in spring, whereas the mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, and the concentrations of cholesterol, total bilirubin and creatinine were lower. Adult males had higher RBCs and haemoglobin values than females in summer, and lower leucocyte, lymphocyte and neutrophil counts than females and yearling males. The concentrations of triglycerides, total bilirubin, lactate, creatinine, urea, chloride and alpha2-globulins were higher in adult males than yearling males. In summer the adult females had higher values for platelets, lymphocytes, cortisol, sodium and muscular enzymes.     

Equine vitreous humor chemical concentrations: correlation with serum concentrations, and postmortem changes with time and temperature.

Samples of equine vitreous humor were analyzed for urea nitrogen, creatinine, sodium, chloride, phosphorus, calcium, potassium, and magnesium concentrations. Fresh vitreous chemical concentrations were compared to corresponding serum concentrations and expressed as a vitreous to serum ratio. The effects of postmortem time and temperature on the stability of the chemical concentrations were determined by incubation of the samples at 4 degrees C, and 20 degrees C and 37 degrees C for 6, 12, 24, or 48 h. Chemical concentrations were generally more stable at lower temperatures and shorter incubation times.     

Reference blood chemical values in ostriches (Struthio camelus)

Reference blood chemical values were determined for 65 male and 61 female ostriches (Struthio camelus) 1 month to 72 months of age. Plasma values of glucose, total protein, triglycerides, cholesterol, uric acid, urea, bilirubin, creatinine, osmolality, electrolytes, and enzyme activity were determined. In general, differences in various values appeared mainly among age groups and less so between sexes. Older ostriches had lower plasma glucose values and enzyme activity than did younger ostriches. High plasma sodium and chloride concentrations in young ostriches correlated with high plasma osmolalities. Plasma calcium values were lower in laying ostriches. Uric acid concentrations were markedly higher than were urea concentrations in all ostriches.     

Physical and clinical pathological findings associated with experimentally induced rupture of the equine urinary bladder

Two mature horses were examined for changes in laboratory and physical findings after experimentally induced bladder rupture. The postrupture laboratory diagnostic changes, which provide valuable information for a correct diagnosis are described. Hematology, serum and peritoneal fluid sodium, potassium, calcium, phosphorous, creatinine, urea nitrogen, albumin and peritoneal fluid components were measured and evaluated versus time. Hyponatremia and hyperkalemia occurred, as well as increased concentrations of peritoneal fluid potassium and inorganic phosphorus. In addition, peritoneal fluid creatinine:serum creatinine and peritoneal fluid urea nitrogen:serum urea nitrogen ratios were followed with time. Hematology and cytology of the peritoneal fluid showed an inflammatory response to urine contamination of the abdominal cavity. Physical findings of tachypnea and tachycardia as well as a mild colic were absent until nearly 50 hours postrupture. Based on these findings, it was concluded that the peritoneal fluid creatinine:serum creatinine ratio was the most useful antemortem laboratory diagnostic aid.     

Comparison of two dry chemistry analyzers and a wet chemistry analyzer using canine serum

Canine serum was used to compare seven chemistry analytes on two tabletop clinical dry chemistry analyzers, Boehringer's Reflotron and Kodak's Ektachem. Results were compared to those obtained on a wet chemistry reference analyzer, Roche Diagnostic's Cobas Mira. Analytes measured were urea nitrogen (BUN), creatinine, glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholesterol and bilirubin. Nine to 12 canine sera with values in the low, normal, and high range were evaluated. The correlations were acceptable for all comparisons with correlation coefficients greater than 0.98 for all analytes. Regression analysis resulted in significant differences for both tabletop analyzers when compared to the reference analyzer for cholesterol and bilirubin, and for glucose and AST on the Kodak Ektachem. Differences appeared to result from proportional systematic error occurring at high analyte concentrations.     

Effect of age on reference intervals of serum biochemical values in kittens

OBJECTIVE: To determine the effect of age on reference intervals of serum biochemical values in kittens. DESIGN: Prospective clinical trial. ANIMALS: 55 kittens from 12 specific-pathogen-free queens. PROCEDURE: Kittens were allocated at birth into colostrum-fed (n = 27) and colostrum-deprived (28) groups. Blood was collected at birth and on days 1, 2, 4, 7, 14, 28, and 56. Serum samples were analyzed for activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, gamma-glutamyltransferase, amylase, and lipase and for concentrations of albumin, total protein, bilirubin, urea nitrogen, creatinine, cholesterol, glucose, calcium, phosphorus, and triglycerides by use of an automated analyzer. Total serum solids concentrations were determined by use of refractometry. Serum IgG concentrations were quantified by use of radial immunodiffusion. RESULTS: For several analytes, reference intervals changed rapidly, most notably during the first few days of life. Reference intervals for alkaline phosphatase, creatine kinase, lactate dehydrogenase, and triglycerides were higher from birth to 8 weeks than adult reference intervals. Aspartate aminotransferase, bilirubin, urea nitrogen, and creatinine were higher than in adults at birth but were similar to or lower than adult reference intervals by 8 weeks. Compared with adult reference intervals, reference intervals for calcium and phosphorus concentrations were higher and for albumin and total protein concentrations were lower throughout the study period. CONCLUSIONS AND CLINICAL RELEVANCE: Important differences exist between reference intervals for serum biochemical values of neonatal and adult cats. Age-appropriate reference intervals should be used for accurate assessment of serum biochemical test results in cats.     

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.     

Postmortem biochemical markers of experimentally induced hypomagnesaemic tetany in cattle

Severe hypomagnesaemia and tetany were induced in 10 lactating cows by feeding them semi-synthetic low magnesium diets and the animals were used to study the stability of postmortem markers of hypomagnesaemic tetany. There were significant relationships between the concentrations of magnesium in either cerebrospinal fluid (CSF) or plasma and either aqueous or vitreous humour. The onset of hypomagnesamic tetany was also associated with low magnesium concentrations in plasma, CSF and aqueous and vitreous humour. Magnesium concentrations less than 0.25 mmol/litre in fresh aqueous humour may be indicative of severe hypomagnesaemia and possible tetany in lactating cows, but the concentration of magnesium in aqueous humour was unstable postmortem. The concentration of magnesium in vitreous humour was relatively stable and a concentration of less than 0.55 mmol/litre could be used as a diagnostic marker of tetany in cattle for up to at least 48 hours postmortem, at ambient temperatures typical of Northern Ireland.     

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.     

Effects of storage time and freezing temperature on clinical chemical parameters from canine serum and heparinized plasma

To assess changes in 24 blood constituents in frozen serum and heparinized plasma, blood samples were drawn from 10 clinically normal German Shepherd army dogs. The storage characteristics of nine enzymes (ALP, ALT, amylase, AST, CK, GGT, GLDH, LDH, lipase), and 15 metabolites and minerals (albumin, bile acids, bilirubin, calcium, cholesterol, creatinine, fructosamine, glucose, magnesium, phosphate, potassium, protein, sodium, triglycerides, urea) were studied. Parallel samples of serum and heparinized plasma were stored for 90 and 240 days at two different storage temperatures, -200 degrees C and -700 degrees C. Sixteen of the 24 analytes (ALP, ALT, amylase, AST, CK, GGT, GLDH, LDH, bile acids, calcium, cholesterol, creatinine, fructosamine, magnesium, phosphate, urea) showed statistically significant (p < 0.05) changes during the storage period related to storage time, storage temperature, and sample type. Seven of the analytes (amylase, GGT, GLDH, LDH, bile acids, fructosamine, magnesium) showed changes of possible clinical importance with mean differences from baseline larger than 20% for the enzymes and 10% for the metabolites and minerals during the storage periods.     

On the clinical chemistry of the Bennett's wallaby (Macropus rufogriseus rufogriseus)

The following parameters were determined in blood serum of apparently healthy Bennett's wallabies (Macropus rufogriseus) using the Hitachi 917 (Roche Diagnostics, Mannheim, Germany) and/or the Vettest 8008 (IDEXX-GmbH, Woerrstadt, Germany): alkaline phosphatase, alanine aminotransferase, ammonia, alpha-amylase, aspartate aminotransferase, Ca, Cl, cholesterol, cholinesterase, creatine kinase, creatinine, gammaglutamyltransferase, glucose, iron, lactate dehydrogenase, magnesium, phosphate, potassium, protein, sodium, total bilirubin, triglyceride, and urea. The results for cholesterol, glucose, total protein, triglyceride and for the enzymes alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyltransferase and lactate dehydrogenase differed significantly between both methods (P < 0.05). There is a negative correlation between the age of the Bennett's wallabies and the activity of the alkaline phosphatase. Five protein fractions could be separated on cellulose acetate electrophoresis. The mean concentrations of fructosamine and beta-hydroxybutyrate were 447.3 micromol/L and 0.27 mmol/L, respectively. The estimated vitamin A intake had no influence on the vitamin A concentration in serum. The serum vitamin E concentration was in general low and vitamin E was below the detection limit of 0.82 micromol/L in 29 out of 42 serum samples. The use of these analytes is discussed concerning the knowledge about the physiology, nutrition and diseases of macropods.     

Analysis of canine and feline blood samples using the Kuadro in-house wet-reagent chemistry analyser

OBJECTIVES: Kuadro is a new wet-reagent biochemistry analyser that is available for in-house use. The aim of this study was to compare the results produced by this analyser with those obtained by a wet-reagent analyser (KoneLab 30i) that served as the reference instrument. METHODS: Blood samples from 80 clinical cases (40 dogs and 40 cats) were analysed for urea, creatinine, total proteins, albumin, glucose, cholesterol, alanine aminotransferase, alkaline phosphatase, total bilirubin, amylase, total calcium, and phosphate using both the reference and Kuadro instruments. RESULTS: Kuadro performed very well on canine and feline samples, showing clinically acceptable correlations (r value) (canine/feline) for urea (0.99/0.97), creatinine (0.99/0.98), total proteins (0.95/0.97), albumin (0.98/0.90), glucose (0.99/0.99), cholesterol (0.99/0.99), alanine aminotransferase (1.00/0.99), alkaline phosphatase (0.96/0.99), total bilirubin (1.00/1.00), amylase (0.98/0.96), and phosphate (0.91/0.92). The correlation for total calcium measurements was clinically unacceptable (0.78/0.83). CLINICAL SIGNIFICANCE: Urea, creatinine, albumin, glucose, cholesterol, alanine aminotransferase, and phosphate Kuadro values can be used interchangeably with those generated by the reference analyser. Alkaline phosphatase, amylase, and total proteins Kuadro values cannot be used interchangeably, as Kuadro overestimated alkaline phosphatase and amylase and underestimated total protein measurements. Kuadro significantly underestimated total calcium concentrations due to the shorter incubation time used by the Kuadro analyser compared with the incubation time used in the reference analyser assay system.     

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.     

Tear urea nitrogen and creatinine levels in horse and their correlation with serum values

The objective of this paper was to determine the physiological values of urea nitrogen and creatinine in tears, and to compare the results with those obtained from serum. Thirty healthy thoroughbred horses were included in the study. Tear fluid samples were obtained using a glass capillary tube placed in lower conjunctival cul-de-sac. Blood samples were taken from the jugular vein. Tear and serum urea nitrogen and creatinine levels were quantitatively analyzed by an enzymatic colorimetric method. Urea nitrogen values were 4.22+/-1.84 mmol/l in tears and 4.44+/-1.78 mmol/l in serum, whereas creatinine values in tears were 14.14+/-7.74 micromol/l and in serum 147.63+/-12.17 micromol/l. Statistical analysis confirmed a significant correlation between serum and tear urea levels (P<0001). However, there was no significant correlation between blood and tear creatinine values. Mean value of creatinine obtained from tears was 9.6% of the mean value from serum. Urea nitrogen and creatinine levels can be measured in tears. A significant correlation was found between serum and tears urea levels. This finding may permit development of a new alternative laboratory diagnosis of uremia based on the content of urea in tears.