Comparison of techniques for quantifying alkaline phosphatase isoenzymes in canine serum

Three methods for quantifying the steroid-induced and liver isoenzymes of alkaline phosphatase in canine serum were compared on a group of 29 canine serum samples with increased total alkaline phosphatase activity. Levamisole inhibition, heat inactivation, and affinity electrophoresis with densitometry yielded results that correlated strongly. The relationship between levamisole inhibition and heat inactivation test values was a simple linear one, whereas the relationship between their values and those of electrophoresis was better fitted to an exponential model. The levamisole inhibition and heat inactivation tests provided essentially the same information regarding the relative proportions of steroid-induced and hepatic isoenzymes in canine serum; either test was judged practical for routine clinical application.     

Multiple forms of alkaline phosphatase in horse bone,liver, kidney,duodenum, caecum and serum separated by agarose gel electrophoresis with and without neuraminidase pretreatment

Horse bone, liver, duodenum, caecum and kidney alkaline phosphatases were separated by a commercial agarose gel electrophoresis method with and without neuraminidase pretreatment, following the manufacturer's directions. Tissue extracts were obtained in saline solution and ALP extracted from cell membranes by the butanol method. Electrophoresis was performed using a TRIS/barbital/sodium barbital buffer with detergent, pH 8.6 to 9.0, at 250 V for 30 minutes. Bone, liver and kidney untreated extracts showed two ALP bands each, but with different relative migration (compared to albumin migration). When they were preincubated with neuraminidase, the two bone bands showed a marked decrease in their migration, followed by the kidney ALP bands and the most anodic band of liver Both intestinal untreated extracts showed three bands but with different mobilities. After preincubation with neuraminidase, the three bands of caecum mucosa decreased in their migration, and the most anodic duodenum band disappeared, overlapping the second one. When tissue extracts were incubated with wheat germ-lectin (WGL), 74.5% of bone extract ALP and 67.2% of caecum extract ALP precipitated, which demonstrated that the ALP band of both tissues have similar groups in the carbohydrate side chains. Horse serum showed two electrophoretic bands, which increased to three bands when treated with neuraminidase. ALP from hepatocytes was the dominant isoform, followed by a caecum band. Because the electrophoretic mobilities of some of the tissue bands studied were identical, the neuraminidase agarose electrophoretic method appeared to be a satisfactory alternative to separate them.     

Consecutive changes in serum alkaline phosphatase isoenzyme 3 activities in Holstein heifers during the first 18 months of life

This study investigated consecutive fluctuations in serum activities of bone-specific alkaline phosphatase (ALP) isoenzyme 3 (ALP3) in 11 clinically healthy Holstein heifers during the first 18 months of life. ALP3 activities at the first sampling time point after weaning (3 months) were significantly lower than those at multiple time points during the pre-weaning period. Those activities increased from a minimum at 3 months to a peak at 6 months during the post-weaning period. In the anthropometric data, daily body weight and wither height gains appeared to be below the public data at 4 months and 4–5 months, respectively. The data suggested that serum ALP3 activity can be used to monitor skeletal growth of heifers at weaning.     

Canine serum alkaline phosphatase isoenzymes detected by polyacrylamide gel disk electrophoresis

Serum alkaline phosphatase (ALP) isoenzymes were studied in normal dogs using a commercially available polyacrylamide gel disk electrophoresis kit (PAG/disk kit). Serum samples taken from the dogs were incubated with neuraminidase, after which most showed ALP isoenzymes as two characteristic stained bands. To determine the origin of each band, ALP isoenzymes of serum and tissue extracts (liver, intestine and bone) were characterized by heating, wheat germ agglutinin (WGA) and levamisole treatments. The results suggested that the band detected on the anode was liver ALP (LALP) and that the band detected on the cathode represented bone ALP (BALP), and both were corticosteroid-induced ALP (CALP). The percentage of each ALP isoenzyme to total ALP activity was estimated by densitometry. The percentage of BALP was the highest in young dogs (age<1 year, 64.7% ), and this value decreased with age. In contrast, the percentage of LALP in young dogs (22.2%) was much lower than that in middle-aged dogs (ages 1 year to 7 years, 59.3%) and old dogs (ages>7 years, 50.4%). The present results suggested that a commercially available PAG/disk kit is capable of detecting three serum ALP isoenzymes in dogs, and further that it may have clinical applications in the evaluation of ALP isoenzymes in veterinary medicine.     

Agarose gel serum protein electrophoresis in cats with and without lymphoma and preliminary results of tandem mass fingerprinting analysis

Background: Serum electrophoretic profiles in cats are poorly characterized with respect to the proteins that comprise the globulin fractions, and interpretation of the electrophoretograms is routinely done in the absence of information about identity of the proteins found within each fraction. Objectives: The aims of this study were to compare protein fractions separated by serum protein electrophoresis (SPE) in healthy cats and in cats with lymphoma and to confirm some component proteins in the major fractions following SPE using tandem mass fingerprinting analysis (TMFA). Methods: Total protein concentration was measured and agarose gel SPE performed on serum from 14 healthy cats and 14 cats with lymphoma. The absolute protein concentration within each fraction was compared between the 2 groups. Bands corresponding to the SPE fractions were excised from the gels of 2 control cats and 1 cat with lymphoma and analyzed by liquid chromatography coupled to mass spectrometry. Results were compared with sequences in the National Center for Biotechnology Information protein database. Results: Median albumin concentrations were significantly decreased and median β‐globulin concentrations were significantly increased in cats with lymphoma. Narrow electrophoretic spikes were present in the β/γ‐globulin fraction in 3 cats with lymphoma. Following TMFA, multiple proteins were identified in each fraction, and their mobility agreed with results from previous studies generated using alternative techniques. Inter‐α (globulin) inhibitor 4 was identified in feline serum for the first time. Conclusions: Cats with lymphoma had lower albumin and higher β‐globulin concentrations than did healthy cats. Despite limitations of one‐dimensional agarose gel SPE, TMFA provided preliminary data to confirm the protein components of the various fractions.     

Quantification of bone alkaline phosphatase in canine serum

An assay was developed and proven accurate and precise for the quantification of canine serum alkaline phosphatase of bone origin (BAP). The assay uses wheat germ lectin (WGL) which selectively precipitates SAP but not liver alkaline phosphatase (LAP) in serum preincubated for 1 hour at 37 degrees C before conducting the assay. Although a large percentage of corticosteroid-induced alkaline phos- phatase (CAP) is also precipitated by WGL, the activity of this isoenzyme can be determined by utilizing the automated levamisole inhibition assay and BAP determined by subtraction except in those cases in which CAP is very markedly increased. Use of these two assay techniques in combination allows the quantification of LAP, BAP, and CAP activity in canine serum. In sera from adult dogs of various ages, BAP activity represents a mean of 21.27 -/+ 11.4 U/L; however, there was a statistical decrease in BAP activity with age. This allowed the determination of 95% confidence interval for a reference range dependent on age of the dog. Bone AP activity in puppies drops dramatically within the first 3 months, reaching a magnitude of activity consistent with that of the adult dog by approximately 15 months. BAP was increased over adult reference range in five of five dogs tested with osteosarcoma. This assay will now allow conducting a clinical study of the diagnostic significance of bone AP activity in neoplastic and metabolic diseases of bone.     

Comparison of results from the semiautomated serum bone alkaline phosphatase isoenzyme assay with the periosteal alkaline phosphatase assay for use in rat models

BACKGROUND: Assessment of bone formation activity is an important component of pharmacologic efficacy and toxicity evaluations for compounds in development for osteoporosis therapies. Antemortem biomarkers of bone formation and remodeling in rodents are uncommon. While the periosteal alkaline phosphatase (ALP) assay is a postmortem and laborious means of testing bone-building activity, the semiautomated ALP isoenzyme assay is an antemortem assay that is performed on an automated chemistry analyzer after 2 simple dilutions of the initial serum sample and a short incubation. OBJECTIVES: The goal of our investigation was to determine if the serum bone ALP (BALP) data obtained from the semiautomated ALP isoenzyme assay had a similar pattern of response when compared with the periosteal ALP (PALP) assay for use in pharmacologic screening in rats. METHODS: Serum and bone tissue samples were obtained from orchidectomized Wistar rats, a model of clinically induced osteoporosis. Subsequent bone formation was initiated via treatment with one of several compounds. In study 1, orchidectomized male rats were given either vehicle, dihydrotestosterone or a testosterone derivative subcutaneously every 4 days for 28 days. In study 2, orchidectomized male rats were given either vehicle or compounds A, B, or C by oral gavage daily for 15 days. Blood and tibias were collected at necropsy. Serum was analyzed for BALP activity using a semiautomated ALP assay. Tibias from the same rats were analyzed for PALP activity. RESULTS: Serum BALP activity paralleled PALP activity within each group when compared with the controls. CONCLUSION: Our data indicate that the semiautomated serum BALP isoenzyme assay may be used as a biomarker of bone-building potential in rat models of osteoporosis. This assay affords many advantages to investigators of musculoskeletal diseases, including the potential to measure multiple data points in a single study.     

Alkaline phosphatase isoenzymes in feline serum using an agarose gel alkaline phosphatase kit method.

Total serum alkaline phosphatase (ALP) activity is the product of the combined activity of isoenzymes from a number of tissue sources. In this study, a commercially available kit for electrophoretic separation of ALP isoenzymes in an agarose gel was used to separate ALP isoenzymes in feline tissue extracts and serum. Five separate bands of ALP activity were identified. These bands were numbered 1 to 5 with band 1 having the most anodal migration. The tissue of origin corresponding to the migration position of the isoenzymes are as follows: Band 3 was the liver isoenzyme, band 4 was the bone isoenzyme and ALP isoenzymes of both intestine and kidney migrate in the position labelled band 5. Band 1 appears to be related to albumin and does not represent true ALP activity. The tissue source of band 2 (a and b) was not identified. Serum ALP activity of mature, healthy cats is primarily of liver origin. Immature cats (< 1 year of age) have a greater proportion of the bone isoenzyme in the serum.     

Tissue sources of serum alkaline phosphatase in 34 hyperthyroid cats: a qualitative and quantitative study

The concentration of serum alkaline phosphatase (SALP) is commonly elevated in hyperthyroid cats. Agarose gel electrophoresis, in tris -barbital-sodium barbital buffer, with and without the separation enhancer neuraminidase, was used to investigate the sources of the constituent isoenzymes of SALP in serum samples from 34 hyperthyroid cats, comparing them to sera from five healthy cats and to tissue homogenates from liver, kidney, bone and duodenum. Contrary to previous reports, treatment of serum with neuraminidase made differentiation of the various isoenzymes more difficult to achieve. A single band corresponding to the liver isoenzyme (LALP) was found in 100 per cent of healthy cats. Eighty-eight per cent of the hyperthyroid cats showed two bands, corresponding to the liver and bone (BALP) isoenzymes while 12 per cent showed a LALP band alone. In hyperthyroid cats, there was a significant correlation between the serum L-thyroxine concentrations and the SALP concentrations. These findings suggest pathological changes in both bone and liver in most cases of feline thyrotoxicosis.     

Agarose gel electrophoretic separation of blood serum proteins in cattle.

The agarose gel electrophoresis described by Johansson (1972) was modified so that a buffer of pH 7.9 was used in the gel, whereas the buffer in the electrode vessels had a pH of 8.6.The cattle blood serum protein picture is described in detail. The β₁-globulin zone shows a very distinct picture of the genetically polymorphic bovine transferrins. The region between the α- and β-globulins shows a number of faint and often very distinct bands. A faint background staining over the whole electrophoretogram may partly be caused by a rather strong lipoprotein in the α₁-region, lipids thus having migrated all over the electrophoretogram.The modified method described is well suited as a “screen electrophoresis” for cattle serum and is also useful e.g. in studying bovine transferrin polymorphism.     

Semiautomated analysis of alkaline phosphatase isoenzymes in serum of normal cynomolgus monkeys (Macaca fascicularis)

Alkaline phosphatase (ALP) isoenzyme analysis, using a combination of wheat germ lectin (WGL) precipitation, levamisole inhibition and an automated p-nitrophenylphosphate assay was validated for use with serum from monkeys (Macaca fascicularis) and used to determine the activities of liver ALP (LALP), bone ALP (BALP) and intestinal ALP (IALP). Based on serial dilution studies and within-run and between-run coefficients of variation, each assay had excellent linearity and acceptable precision. In addition, liver and intestinal mucosa extracts for tissue specific alkaline phosphatases were used to confirm assay validations. Gender-specific differences for total ALP, LALP, and BALP activities were present in sera from normal monkeys between 2 and 4 years of age. Males had 1.3-fold higher total ALP and LALP activities, and 1.5-fold higher BALP activity compared with females. The majority of ALP activity in normal monkey serum was LALP isoenzyme activity, which ranged from 56.7% to 94.7% of total activity. Serum BALP activity ranged from 5.3% to 42.8%. There was negligible IALP activity in all serum samples.     

Serum alkaline phosphatase isoenzyme profiles in phenobarbital-treated epileptic dogs

BACKGROUND: Serum total alkaline phosphatase (AP) activity commonly is high in dogs receiving phenobarbital. Specific isoenzymes responsible for this increase are not well documented. OBJECTIVES: The purposes of this study were 1) to qualitatively and quantitatively describe serum AP isoenzymes in phenobarbital-treated dogs and 2) to monitor changes in serum AP isoenzyme activities associated with phenobarbital treatment over time. METHODS: Serum AP isoenzyme activities were determined in a cross-sectional study of 29 dogs receiving phenobarbital (duration of treatment 2 months to 6.5 years). Additionally, in a prospective study of 23 dogs, serum AP isoenzyme activities were determined before and 3 weeks, 6 months, and 12 months after the start of phenobarbital treatment. Isoenzyme activities were quantitatively determined using wheat germ lectin precipitation and levamisole inhibition, and qualitatively (ie, present or absent) evaluated using cellulose acetate affinity electrophoresis. RESULTS: In phenobarbital-treated dogs with high serum total AP activity in the cross-sectional study, the increase was due predominantly to increased activities of the corticosteroid-induced (C-AP) and liver (L-AP) isoenzymes. Prospectively, serum total AP and L-AP activities were significantly higher at 3 weeks, 6 months, and 12 months after the start of phenobarbital treatment compared with pretreatment values. Serum C-AP and bone isoenzyme (B-AP) activities were significantly higher after 6 and 12 months of treatment. B-AP accounted for only a small amount of the total AP activity. No unusual or previously unidentified AP isoenzymes were identified. CONCLUSIONS: Phenobarbital treatment was associated with increased C-AP and L-AP isoenzyme activities and with a minor increase in B-AP activity. No unique "phenobarbital-induced" isoenzyme was identified. Isoenzyme analysis does not appear to be useful for differentiating between high serum total AP due to phenobarbital therapy and other causes.     

Alkaline phosphatase bone isoenzyme and osteocalcin in the serum of hyperthyroid cats.

The effect of hyperthyroidism on serum markers for increased bone metabolism and turnover was evaluated in 36 cats with elevated serum levels of thyroxine and alkaline phosphatase. Serum was analyzed for total and ionized calcium and phosphorous. Alkaline phosphatase isoenzymes were separated by agarose gel electrophoresis and osteocalcin was measured by radioimmunoassay. Values for hyperthyroid cats were compared with those for healthy cats. Alkaline phosphatase bone isoenzyme was markedly increased in all 36 hyperthyroid cats. Osteocalcin was increased in 44% of the cats. There was no correlation among the magnitude of increase in alkaline phosphatase bone isoenzyme, osteocalcin, and serum thyroxine concentrations. Increased serum phosphorus was found in 35% of the cats. Total calcium was within the reference range in all cats, while 50% of the cats had reduced levels of serum ionized calcium. We conclude that hyperthyroid cats do have altered bone metabolism, although it is usually clinically insignificant.     

Alkaline phosphatase and alkaline phosphatase isoenzymes in the cat

Feline alkaline phosphatase and alkaline phosphatase isoenzymes have been studied in tissue and serum. Alkaline phosphatase from various organs was quantitated and then subjected to cellulose acetate electrophoresis. The effects of bile duct ligation, prednisolone treatment and phenobarbital treatment on serum alkaline phosphatase was measured. The diagnostic importance of feline serum alkaline phosphatase levels is discussed in light of the results of this and other studies.     

Ultrasonographic measurements of adrenal glands in cats with hyperthyroidism

Feline hyperthyroidism is potentially associated with exaggerated responsiveness of the adrenal gland cortex. The adrenal glands of 23 hyperthyroid cats were examined ultrasonographically and compared to the adrenal glands of 30 control cats. Ten hyperthyroid cats had received antithyroid drugs until 2 weeks before sonography, the other 13 were untreated. There was no difference in adrenal gland shape between healthy and hyperthyroid cats: bean-shaped, well-defined, hypoechoic structures surrounded by a hyperechoic halo in 43/60 (71.6%) healthy cats and 34/46 (73.9%) hyperthyroid cats; more ovoid in 13/60 (21.6%) healthy cats and 9/46 (19.6%) hyperthyroid cats while more elongated in 4/60 (6.7%) healthy cats, 3/46 (6.5%) hyperthyroid cats. Hyperechoic foci were present in 9/23 (39.1%) hyperthyroid cats and 2/30 (6.7%) healthy cats. The adrenal glands were significantly larger in hyperthyroid cats, although there was overlap in size range. The mean difference between hyperthyroid cats and healthy cats was 1.6 and 1.7 mm in left and right adrenal gland length, 0.8 and 0.9 mm in left and right cranial adrenal gland height, and 0.4 and 0.9 mm in left and right caudal adrenal gland height. There was no significant difference between the adrenal gland measurements in treated and untreated hyperthyroid cats. The adrenomegaly was most likely associated with the hypersecretion of the adrenal cortex documented in hyperthyroid cats. Hyperthyroidism should be an alternative to hyperadrenocorticism, hyperaldosteronism, and acromegaly in cats with bilateral moderate adrenomegaly.     

Propagation of bovine coronavirus in clones of the Caco-2 cell line showing different levels of alkaline phosphatase activity

The aim of the present study was to determine whether bovine coronavirus (BCV) has the ability to initiate infection in a human colon carcinoma cell line, Caco‐2, that has been established to spontaneously differentiate after confluence. When Caco‐2 cells were infected with BCV, a titer of 5.5 × 10⁶ plaque‐forming units (p.f.u.)/mL was found in the culture supernatant at 5 days postinfection. Two clones, Caco‐2/CA1 and Caco‐2/CA2, were then isolated by monitoring alkaline phosphatase (ALP) and cell proliferation activities. The ALP activity level of CA1 cells was significantly higher than that of CA2 cells, while the level of cell proliferation activity of CA1 was significantly lower than that of CA2. When CA1 and CA2 cells were infected with BCV at confluence, virus hemagglutination (HA) was detected in the culture supernatant at 5 days postinfection for CA1 cells and at 8 days postinfection for CA2 cells. Thus, BCV propagation was substantially delayed in CA2 cells, suggesting that a cellular factor(s) that appears at the differentiation stage may control BCV propagation. BCV‐susceptible CA1 and CA2 cells showing different levels of ALP activity would be useful for further experiments to elucidate the mechanism of BCV propagation.     

Separation of serum glycated proteins by agarose gel electrophoresis and nitroblue tetrazolium staining in diabetic and normal cats

BACKGROUND: The total glycated protein (fructosamine) concentration in serum consists mainly of glycated albumin and lipoproteins. Measurement of fructosamine is used to diagnose and monitor diabetes mellitus in cats. OBJECTIVE: The aims of this study were to measure glycated proteins in diabetic and healthy (nondiabetic) cats using a semiquantitative technique and to determine whether measurement of any of the fractions of glycated protein could be potentially advantageous for the diagnosis and monitoring of diabetic cats. METHODS: Serum samples from 6 cats with diabetes mellitus and 10 clinically healthy adult cats were assayed for total glycated protein using a nitroblue tetrazolium (NBT) fructosamine assay. Serum proteins were separated by agarose gel electrophoresis and stained with NBT to identify individual glycated proteins within the bands. Gels were scanned by densitometry at 525 nm and the glycated protein content was calculated with reference to the total glycated protein content of the sample. RESULTS: Diabetic cats with increased total fructosamine concentrations had higher concentrations of glycated albumin and glycated alpha- and beta-lipoproteins compared with healthy cats. The concentration of glycated proteins in each of the fractions had a positive linear association with the total glycated protein content of serum, but there was large variation in the relative contributions of the 3 protein fractions to the total glycated protein concentration. CONCLUSIONS: Based on the results of this study, measurement of individual glycated fractions does not seem to offer any potential diagnostic advantage over measurement of total glycated protein (fructosamine) concentration alone. In some diabetic and healthy cats, glycated lipoproteins formed the major part of the total glycated protein, whereas in other cats albumin was the major contributor.