Reference intervals for the activity of lactate dehydrogenase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines

Background

Lactate dehydrogenase (LD) exists as 5 isoenzymes (LD‐1 through LD‐5) that are expressed throughout the body and can be detected in both serum and cerebrospinal fluid (CSF). LD and its isoenzymes have been relatively unstudied in veterinary medicine, although studies in human medicine have demonstrated that changes in total LD activity and atypical isoenzyme patterns can indicate disease processes, including neurologic abnormalities.

Objectives

The purpose of this study was to establish RIs for LD and its isoenzymes in the serum and CSF of clinically healthy dogs. By establishing a definitive RI for this enzyme in healthy canines, further study of the clinical and diagnostic usefulness of LD can be undertaken.

Methods

Serum and atlantoaxial CSF were collected from clinically healthy dogs. Total LD activity was measured spectrophotometrically immediately after collection. Isoenzyme distributions were also determined within 8 hours of collection using the QuickGel LD Isoenzyme technique and a densitometric scanner.

Results

The median serum total LD in healthy canines was 69.0 U/L (n = 41; range: 21.0‐217.0 U/L), while the median CSF total LD was 10.0 U/L (n = 40; range: 6.0‐19.3 U/L). LD‐5 is the predominant isoenzyme in canine serum (n = 40), contributing over half of the total enzyme activity. Conversely, in canine CSF (n = 42), LD‐1 is the predominant isoenzyme, followed by LD‐2 and LD‐3.

Conclusions

Knowledge of the distribution and concentration of LD in the serum and CSF of healthy dogs will set the foundation for future studies of canine LD as a potentially clinically useful biomarker.     

Evaluation of a cattle rapid test for early pregnancy diagnosis in sheep

Tropical Animal Health and Production - The early pregnancy diagnosis allows optimizing production and timely management correction, with a greater reproductive output of livestock. The Idexx Rapid...     

Activity of serum creatine kinase, lactate dehydrogenase and LD isoenzymes in piglets affected with congenital tremor: a case report.

The activities of serum creatine kinase (CK), lactate dehydrogenase (LD) and LD isoenzymes were studied in 14 Prestice black pied pigs from a herd affected with congenital tremor. Mean CK activity was 19.57 +/- 3.56 mu kat.l-1 for 6 adult pigs, and it was 21.03 +/- 1.33 mu kat.l-1 and 20.42 +/- 1.23 mu kat.l-1 for the affected (n = 5) and control (n = 3) piglets, respectively. No significant differences were demonstrable between the groups in CK activity. Total serum LD and LD-4 as well as LD-5 isoenzyme activities were higher in sows. Piglets affected with congenital tremor showed an increase in total LD enzyme and LD-5 isoenzyme activity. It is concluded that no relationship exists between congenital tremor and serum CK activity in piglets. At the same time, there is a positive relationship between congenital tremor and significantly (P < 0.01) elevated LD enzyme and LD-5 isoenzyme activity. The results allow us to suggest that total lactate dehydrogenase and LD-5 isoenzyme activities could be used as biological markers of congenital tremor in piglets.     

Evaluation of a micro method for the routine determination of serum pepsinogen in cattle

Estimation of serum pepsinogen concentration in cattle is used to aid the detection of clinical or subclinical infections with the abomasal nematode Ostertagia ostertagi. An inexpensive, simple micro method for the routine determination of pepsinogen concentration in bovine serum samples is described which is based on the hydrolysing effect of serum on buffered bovine albumin substrate. Comparison of this assay with a macro method, based on the same principle, gave almost identical results in the range of 0 to 10 Units tyrosine. The reproducibility of the assay was shown to be very satisfactory, intra-assay and day-to-day coefficients of variations were less than 4·7 and 8 per cent, respectively.     

牛、羊布鲁氏菌病试管凝集试验与微量凝集试验检测方法的比较

血清学检测方法因其快速、安全、高效等特点被广泛应用于布鲁氏菌病的检测和诊断。本文通过对保存的226份牛、羊血清样品同时使用试管凝集法与微量凝集试验进行检测并比较分析其在诊断中的意义。结果显示,微量法与试管法两者的符合率为97.79%,两种检测方法无统计学差异。但微量法的阳性检出率要高于试管法,同时由于微量法具有操作简便、快捷及结果判定更为直观、简单等优点,因此,微量凝集试验更适宜在我国基层布鲁氏菌病大量样本监测、诊断中推广应用。     

Evaluation of a portable glucose meter for use in cattle and sheep

Background: In farm animal practice, determination of blood glucose concentration under field conditions is often necessary. Objective: As there is no portable glucose meter device developed for use in farm animals, the analytical accuracy of a portable glucometer designed for people was evaluated for its use in cattle and sheep. Methods: Blood samples from 90 cattle and 101 sheep were used in the study. Glucose concentration was determined in whole blood immediately after blood collection from the jugular vein with the One Touch Vita portable glucometer and in serum with an enzymatic colorimetric method. The agreement between methods was assessed by Passing and Bablok regression analysis. The precision and the accuracy of the measurements were determined using the concordance correlation coefficient. Results: There was a strong linear relationship between the glucose values obtained using the portable glucometer and those obtained by the bench method in both cattle and sheep. Precision was 95% for cattle and 88% for sheep, whereas accuracy was 92% and 99%, respectively. The mean glucose values obtained using the portable glucometer were significantly lower by 8.3% in cattle and 3.2% in sheep than those determined by the bench method. Conclusion: The One Touch Vita portable glucometer can be used in clinical practice to determine blood glucose concentrations in cattle and sheep, but reference intervals (RI) must be corrected to allow for negative bias. Based on these equations the RI for blood glucose in cattle and sheep using the portable glucometer were corrected to 1.84–4.17 and 2.41–4.35 mmol/L, respectively.     

Isoenzymes of lactate dehydrogenase in swine. Stability during storage at different temperatures and by heat treatment

The isoenzymes of lactate dehydrogenase (LDH) in serum from normal pigs were studied after separation by agar gel electrophoresis with subsequent staining with a tetrazolium salt.Experiment 1. The stability of isoenzymes was investigated for 5 successive days after storage at room temperature (22°C), in the refrigerator (4°G), and once after storage for 32 days in the deep-freezer (—20°C). Greatest loss of activity was seen after storage in the refrigerator, where LDH₂ and LDH₃ lost most of its activity after 5 days. In LDH₄ and LDH₅ no loss had occurred at this time. Also at room temperature great losses were seen in LDH₂ and LDH₃. After storage in the deep-freezer an increase in LDH₃ activity was recorded.Experiment 2. Serum samples were kept in water baths for 30 min. at 50, 53, and 56°C. A simultaneous and increasing loss in activity of LDH₃, LDH₄, and LDH₅ was seen from 50° to 56°C. At 56° no activity was left in LDH₃, LDH₄, or LDH₅, and only about 15 % of the original activity was present in LDH₂. LDH₁ showed no loss at 56°, but all activity was lost at 65°.A close correlation was found between total lactate dehydrogenase and α-hydroxybutyrate dehydrogenase activity in both experiments.     

Evaluation of a kinetic test kit for the determination of magnesium in bovine serum or plasma

The performance of a new kinetic assay test kit for the determination of magnesium in plasma or serum has been evaluated, using bovine plasma samples. The results obtained were compared with the results from a standard atomic absorption spectrophotometry method and a commercial colorimetric test kit. The kinetic kit compared favourably with the conventional methods and generally gave results with greater precision.     

Improvements in the modified direct complement fixation test and its application in the detection of bluetongue antibodies in cattle and sheep sera.

In this study, improvements were made in the technique and the preparation of the antigen. It was possible to perform three extractions and elutions resulting in a soluble reactive preparation from each batch of infected mouse brain. This led to an appreciable increase in the yield of highly reactive antigen. The presence of bluetongue antibodies was not detected in 13,210 sheep sera. Of the 13,486 bovine sera tested, only three questionable reactions were obtained. It was possible to determine that two of these animals were imported. Various isolation methods, including transmission trials to susceptible sheep followed by serological tests on the sheep sera, failed to confirm the infection in the three reactors.     

Enhancement of Leptospira hardjo agglutination titers in sheep and goat serum by heat inactivation.

Heat inactivation of sheep serum samples resulted in the detection of an additional 9% reactors to Leptospira hardjo that were negative on the initial test of fresh samples. Treatment with EDTA gave results generally similar to heat inactivation suggesting that complement was responsible for the inhibition of agglutination. Tests on heat inactivated serum from experimentally infected sheep and goats revealed enhanced titers or reactions which were not detected in fresh serum.     

Development of a method for determination of cyanide concentrations in serum and rumen fluid of cattle

OBJECTIVES: To develop a reliable method for measurement of cyanide concentrations in cattle, using gas chromatography-mass spectrometry (GC-MS), and establish reference ranges of cyanide concentrations in cattle. ANIMALS: 52 Fleckvieh cattle. PROCEDURE: Cattle were allocated to 3 groups; 12 were fed leguminous grass and hay, 36 were fed whole-maize and corn-cob silages, and 4 were fed other feedstuffs. Samples of blood, rumen fluid, and liver were collected at time of slaughter. Serum, rumen fluid, and liver homogenate were assayed for cyanide content, using a derivatization procedure. A technique for analysis by GC-MS that used selected ion monitoring was developed. RESULTS: Compared with a spectrophotometric method, detection of cyanide in serum and rumen fluid by use of GC-MS was selective and sensitive, with a limit of detection of 0.7 microM. Spectrophotometric analysis yielded false-negative and false-positive results. Thus, the GC-MS method was used for subsequent analysis. In all cattle except 1, cyanide concentration ranged from < 0.7 to 35 microM in serum and from < 0.7 to 28 microM in rumen fluid; cyanide concentration in that 1 animal was 206 microM. Cattle fed clover, grass, grass hay, and clover hay had 8.3- to 8.6-fold higher mean cyanide concentrations in rumen fluid and serum than cattle fed whole-maize and corn-cob silages. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study suggest a reference range that should be useful for aiding in the diagnosis of cyanide poisoning. Also, cattle can apparently accommodate a serum cyanide concentration of 206 microM without adverse effects.