Alkaline Phosphatase Isoenzyme Patterns Research Articles

Opinion on Pyridoxal 5'-phosphate as a source for vitamin B6 added for nutritional purposes in food supplements - Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food.

Opinion on Pyridoxal 5'-phosphate as a source for vitamin B6 added for nutritional purposes in food supplements - Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food.

Development and clinical use of a computer assisted decision support system for the interpretation of alkaline phosphatase isoenzyme patterns

Article Development and clinical use of a computer assisted decision support system for the interpretation of alkaline phosphatase isoenzyme patterns was published on January 1, 1994 in the journal Journal of Laboratory Medicine (volume 18, issue 12).

Interpretation and Clinical Significance of Alkaline Phosphatase Isoenzyme Patterns

Alkaline phosphatase (ALP, EC 3.1.3.1) is a membrane-bound metalloenzyme that consists of a group of true isoenzymes, all glycoproteins, encoded for by at least four different gene loci: tissue-nonspecific, intestinal, placental, and germ-cell ALP. Through posttranslational modifications of the tissue-nonspecific gene, for example, through differences in carbohydrate composition, bone and liver ALP are formed. Nowadays, most commercially available methods for separating or measuring ALP isoenzymes are easy to perform and sensitive and allow for reproducible and quantitative results. As more isoenzymes and isoforms have been characterized, confusion has arisen due to the many different names they were given. For the sake of simplicity and because of structural analogies, we propose an alternative nomenclature for the ALP isoenzymes and isoforms based on their structural characteristics: soluble, dimeric (Sol), anchor-bearing (Anch), and membrane-bound (Mem) liver, bone, intestinal, and placental ALP. Together with lipoprotein-bound liver ALP and immunoglobulin-bound ALP, these names largely fit the many forms of ALP one can encounter in human serum and tissues. The clinically relevant isoenzymes are sol-liver, Mem-liver, lipoprotein-bound liver, and Sol-intestinal ALP in liver diseases, and Sol-bone and Anch-bone ALP in bone diseases. Many different isoenzyme patterns can be found in malignancies and renal diseases. This test provides the clinician with valuable information for diagnostic purposes as well as for follow-up of patients and monitoring of treatment. However, ALP isoenzyme determination will only provide clinically useful information if the patterns are correctly interpreted. In this respect, care should be taken to use the proper reference ranges, taking into account the age and sex of the patient. A normal total ALP activity does not rule out the presence of an abnormal isoenzyme pattern, particularly in children. Separating ALP into its isoenzymes adds considerable value to the mere assay of total ALP activity.

Alkaline Phosphatase Isoenzyme Patterns in Malignant Disease

Early treatment of patients with malignant disease and liver or bone metastasis may increase their survival time. We have used the activity patterns of liver and bone isoenzymes of alkaline phosphatase (ALP), separated by agarose gel electrophoresis, to detect early metastasis. We studied ALP isoenzyme patterns in a background population of 101 patients with no evidence of any disease that might influence this pattern; a healthy reference population (n = 330); and the following three groups of patients: 143 with malignant disease, 47 with nonmalignant liver disease, and 22 with nonmalignant bone disease. Cutoff and predictive values of liver ALP, high-molecular-mass (high-M(r)) ALP, and bone ALP were established for detecting liver and bone metastasis. The positive predictive value of liver and high-M(r) ALP was higher than that of total ALP in detecting liver metastasis, but liver and high-M(r) ALP did not enable us to differentiate between malignant and nonmalignant liver disease. Total ALP activity was of slightly more value than liver and high-M(r) ALP in enabling us to rule out liver metastasis. From bone ALP activity we could not distinguish between nonmalignant bone disease and bone metastasis. The negative predictive value of bone ALP in the diagnosis of bone metastasis was low, but its positive predictive value was high and superior to that of total ALP.

Changes in the isoenzyme pattern of alkaline phosphatase in patients with rheumatoid arthritis

Changes in the isoenzyme pattern of alkaline phosphatase in patients with rheumatoid arthritis

Intestinal alkaline phosphatase isoenzyme in patients with primary liver cancer during treatment with N10-propargyl 5, 8-dideazafolic acid (CB 3717).

Serum aspartate transaminase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (gamma GT) activities and the serum ALP isoenzyme pattern have been measured in eleven patients undergoing treatment with CB3717. There were increases in the activity of all three enzymes. The ALP isoenzyme pattern showed an increased contribution of the intestinal isoenzyme to the serum ALP activity. This may be due to increased intestinal mucosal leakage or impaired uptake and breakdown of the intestinal isoenzyme by the liver.

Alkaline phosphatase isoenzyme pattern in human amniotic fluid is dependent on the level of total activity. Implications in cystic fibrosis diagnosis

Alkaline phosphatase activities have been examined in 500 consecutive human amniotic fluids obtained at diagnostic paracentesis between 14 and 38 wk of gestation. They were found to have a non-Gaussian, positively skewed distribution, independent of the protein concentrations. Residual activities after heat treatment or in presence of phenylalanine and levamisole allow evaluation of the placental, hepatic and intestinal isoenzyme components. It is shown that the contribution of the intestinal isoenzyme to the total activity is a linear function of the latter. This fact should be taken into account in the enzymatic diagnosis of cystic fibrosis as it is apparent that the part contributed by the intestinal isoenzyme is predictably smaller when the level of total activity is low.

Clinical assessment of the electrophoretic separation of alkaline phosphatase isoenzymes.

Over a five-month period, using data from patients in whom alkaline phosphatase (ALP) isoenzyme studies were requested routinely, we compared actual clinical diagnoses with the predicted diagnoses based on the results of electrophoretic separation of ALP isoenzymes on cellulose acetate before and after heat treatment and on elevated enzymatic activity of gamma glutamyl transferase (GGT) and alanine aminotransferase (ALT) activity. ALP isoenzymes were interpreted on a qualitative basis (presence or absence of liver, bone, or other isoenzyme) by individual clinical pathologists. Overall, the consistency of agreement in 61 patients was 66% for GGT, 51% for ALP isoenzymes, and 21% for ALT. In 44 patients with definite diagnoses, the sensitivity and specificity, respectively, of each laboratory test for patients with liver disease were 88 +/- 5.7% and 64 +/- 14.5% (ALP isoenzymes); 88 +/- 5.7% and 91 +/- 8.6% (GGT); and 6 +/- 4.1% and 91 +/- 8.6% (ALT). In patients with bone disease, the sensitivity and specificity of ALP isoenzymes was 75 +/- 10.8% and 86 +/- 6.6%, respectively. The results indicate that isoenzymes as currently performed need to be improved through standardization of the interpretation of ALP isoenzyme patterns to establish uniformity of comments.

Purification of an alkaline phosphatase-lipoprotein-X complex.

An alkaline phosphatase isoenzyme was observed in an abnormal position in the agar-agarose gel pattern of sera from several patients suffering from intrahepatic and extrahepatic cholestasis. We purified this isoenzyme, by gel filtration and affinity chromatography, from the serum of a patient suffering from extrahepatic cholestasis. Analysis demonstrated an alkaline phosphatase-lipoprotein-X complex with a relative molecular mass of at least 669,000. We discuss the interpretation of alkaline phosphatase isoenzyme patterns produced by different techniques.

Purification of an alkaline phosphatase-lipoprotein-X complex.

Abstract An alkaline phosphatase isoenzyme was observed in an abnormal position in the agar-agarose gel pattern of sera from several patients suffering from intrahepatic and extrahepatic cholestasis. We purified this isoenzyme, by gel filtration and affinity chromatography, from the serum of a patient suffering from extrahepatic cholestasis. Analysis demonstrated an alkaline phosphatase-lipoprotein-X complex with a relative molecular mass of at least 669,000. We discuss the interpretation of alkaline phosphatase isoenzyme patterns produced by different techniques.

Change in alkaline phosphatase isoenzyme pattern in urine as possible marker for renal disease

The human kidney contains two types of alkaline phosphatase (AP) isoenzymes: a hepatic type of AP and an intestinal-like AP. Intestinal-like AP, measured by immunotitration techniques, is a minor component (1 to 4%) of the total AP activity. It is found only in the particle-free fraction (cytoplasm) and is located, with immunofluorescent techniques, in some of the proximal convoluted tubules. Urinary AP activity is found after high-speed centrifugation in the supernatant (x 100,000g), as well as in the sediment, and may be extracted from the sediment after solubilization with n-butanol. Both types of these renal isoenzymes contribute to urinary AP activity. Biochemical characterization (effect of inhibitors, thermostability, denaturing with urea, and so on) revealed that urinary intestinal-like AP and renal intestinal-like AP are identical. Both, however, have been distinguished as multiple forms of AP from the small intestine. Most of the urinary AP activity of healthy persons (22 volunteers) was found in the sediment and consisted of liver-type AP. Urinary AP of patients with diseases, after application of potentially nephrotoxic drugs or during rejection episodes of renal allografts, contains little sediment activity, but it contains increased amounts of urinary intestinal-like AP.

Alkaline Phosphatase and Hyperthyroidism

Letters and Corrections1 May 1979Alkaline Phosphatase and HyperthyroidismD. G. OREOPOULOS, M.D., PH.D.D. G. OREOPOULOS, M.D., PH.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-90-5-854_1 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the editor: Dr. Cooper and colleagues mention in their recent article "Alkaline Phosphatase Isoenzyme Patterns in Hyperthyroidism" in the February issue (1), that "bone healing in patients with hyperthyroidism may take a prolonged period"; they also observed that "serum alkaline phosphatase may not return to normal for 18 to 24 months after treatment." Further, they mention that the enzyme pattern of alkaline phosphatase from normal before treatment converts to predominant bone in origin after treatment.Velentzas and colleagues (2) have shown that patients with hyperthyroidism have significantly lower plasma levels of 25 hydroxy-vitamin D than do normal controls subjects....

Alkaline phosphatase isoenzyme patterns in hyperthyroidism.

Fifteen of 36 hyperthyroid patients had elevation in serum alkaline phosphatase activity. There was no difference in mean thyroxine (T4), triiodothyronine (T3), age, or duration of illness between the groups with high alkaline phosphatase and normal alkaline phosphatase levels. After treatment, serum alkaline phosphatase levels rose as T4 levels declined; at 3 months, the mean serum alkaline phosphatase value rose from 7.1 Bodansky units to 10.3 Bodansky units (P less than 0.005), while the mean T4 value fell from 18 microgram/dl to 7.2 microgram/dl (P less than 0.005). In some patients, serum alkaline phosphatase values have remained elevated for more than 1 year, despite continued normality in thyroid variables. Before therapy, isoenzyme patterns analyzed by polyacrylamide gel electrophoresis were qualitatively normal. As therapy was instituted, the isoenzyme patterns changed markedly, with increased amounts of bone alkaline phosphatase appearing in the serum as T4 levels were declining and total alkaline phosphatase was rising. Thyroid tissue homogenates from patients with Graves' disease were found to have very low levels of alkaline phosphatase activity and an isoenzyme pattern quite distinct from that found in the serum.

Cytochemical Studies on Alkaline Phosphatase in Uterine Normal and Cancer Cells

In a previous enzyme histochemical study, we showed that some of the uterine reserve cells carried heat stable alkaline phosphatase (ALP), but most of the cervical epidermoid cancers, heat sensitive ALP.From these result, we suspect that ALP isoenzyme pattern may change after malignant transformation (“enzyme deviation”). ALP reaction products in ALP positive cases, however, were not detected in all parts of the lesions but usually only in some parts.In this report, enzyme cytochemical two inhibition tests (heat stability and L-phenylalanine inhibition tests) were also applied to 55 cytological specimens from benign and malignant uterine tissues in order to find how often cell clusters of various of kinds of lesions have ALP activity and which type of ALP isoenzyme they have.The findings in this study may be summarized as follows:1. As in histochemical specimens, ALP activity was also found in cytological specimens of reserve cell, reserve cell hyperplasia after cryosurgery, cervical gland, cervical epidermoid cancer, endometrium in the proliferative phase and endometrial adenocarcinoma.2. In the heat stability test (65°C, 30min.) for cytological specimens, ALP of reserve cell, reserve cell hyperplasia after cryosurgery and cervical gland were heat stable. ALPs of endometrium and epidermoid cancer, however, were heat sensitive. Of 18 cases of endometrial cancer, the ALPs from six were heat stable, and the others heat sensitive.3. In the L-phenylalanine inhibition test, ALPs from all lesions were sensitive to a lesser or greater extent.From these cytochemical studies of ALP, it may be postulated that “enzyme deviation” exists in the course of carcinogenesis of both uterine cervical epidermoid cancer and endometrial adenocarcinoma.

Origin of an elevated plasma alkaline phosphatase activity in non-jaundiced patients.

Samples from 260 non-jaundiced patients with elevated plasma alkaline phosphatase activities were analysed for gamma-glutamyltransferase and 5'-nucleotidase activity, and for alkaline phosphatase isoenzyme pattern. The plasma gamma-glutamyltransferase activity was found to be a more sensitive index than that of plasma 5'-nucleotidase in confirming the presence of a liver component of the elevated plasma alkaline phosphatase. If the gamma-glutamyltransferase level is normal it is probable that the increase in plasma alkaline phosphatase activity is of bone origin. However, and elevated gamma-glutamyltransferase result does not exclude a bone component; in this situation plasma alkaline phosphatase isoenzymes should be estimated. The causes of elevated activities of plasma alkaline phosphatase, 5'-nucleotidase and gamma-glutamyltransferase, found in this investigation were generally the same as those found by other worker. The effect of treatment by drugs on gamma-glutamyltransferase, an inducible enzyme, needs more investigation.

Isoenzyme pattern of alkaline phosphatase in the serum of children with leukaemia after long‐term chemotherapy

Chemotherapy was discontinued in thirteen children with acute lymphoblastic leukaemia after 2-3 years without relapse. In the following months, a continuous increase was observed in the serum alkaline phosphatase. A maximum was reached at different times but all patients had normal values again after 19 months. The rise in the total activity is due to an isolated increase of the bone isoenzyme. Increased enzyme activity in this post-therapy phase of the disease does not signify liver damage from the preceding chemotherapy, but rather is due to an increased osteoblast activity associated with a temporary increase in growth rate.

Serum alkaline phosphatase isoenzyme patterns in patients with chronic renal failure

1. 1. Using acrylamide gel electrophoresis the serum alkaline phosphatase (ALP) isoenzyme patterns of 204 patients with chronic renal failure have been examined for periods up to 18 months in length. 2. 2. Of those with elevated serum ALP activity the bone isoenzyme was largely responsible. The presence of increasing amounts of the bone isoenzyme even if the total serum ALP activity remains within the normal reference range should also indicate bone pathology. 3. 3. Intestinal alkaline phosphatase was the major serum alkaline phosphatase in 15% of patients on regular haemodialysis and 10% of uraemic patients not on dialysis. The overall incidence of detectable intestinal alkaline phosphatase in those with normal serum ALP activity was 36%. 4. 4. With those patients whose serum ALP activity changed significantly during the investigation this usually reflected changes in the amount of the bone isoenzyme. Patients with abnormal amounts of the intestinal isoenzymes in their serum usually showed little variation in serum ALP activity over the period of the study.

Alkaline phosphatase activity in human bladder tumor cell lines.

The cellular localization and isoenzyme pattern of alkaline phosphatase in five cell lines derived from human bladder carcinomas (T24, RT4, RT112, J82, EJ) shown not to be HeLa cells has been established. RT112 cells had a high level of alkaline phosphatase. RT4 had a moderate amount of alkaline phosphatase but in the other three lines, levels were extremely low. Prednisolone caused a small (2 to 3-fold) increase in total alkaline phosphatase in T24 and RT112 lines only. Electrophoretic separation of isoenzymes showed that RT112 and RT4 cells (derived from more highly differentiated tumor types) had three heat stable bands equivalent to placental alkaline phosphatase and three slower bands of a modified placental type. Prednisolone increased only the former. In T24 cells the enzyme resembled the liver-type alkaline phosphatase in electrophoretic mobility and sensitivity to heat denaturation. Cytochemical studies confirmed the presence of cell surface-associated extramembraneous placental type enzyme in RT112 cells. All five cell lines had small deposits of intramembraneous alkaline phosphatase in the plasma membrane and deposits associated tith the mitochondrial membranes and the endoplasmic reticulum that were not completely inhibited by phenylalanine or Levamisole.

Alkaline phosphatase isoenzyme patterns in normal sera of Nigerians

Serum alkaline phosphatase isoenzymes have been examined in Nigerian subjects by cellulose acetate electrophoresis to determine the variations that may occur in the ethnic groups and to establish the normal patterns in health. The results have shown no differences in the isoenzyme distribution patterns in healthy Nigerian and Caucasian subjects.

The diagnostic value of certain alkaline phosphatase isoenzyme patterns in human serum, fractions obtained by polyacrylamide disc electrophoresis

Over 2500 pathological sera were analysed to determine alkaline phosphatase (EC 3.1.3.1) isoenzyme levels. 3% of these sera showed two or more narrow isoenzyme bands with a lower electrophoretic mobility on polyacrylamide than that of the intestine type of alkaline phosphatase and higher than that of the bile type of alkaline phosphatase (the extra-bands group). This latter group showed significantly more intestine-type alkaline phosphatase than a control group of 240 sera lacking extra serum bands. Significantly more of the individuals in the extra-bands group belonged to blood group O or B than did individuals of the control group. This relationship with blood groups suggests that the presence of the extra bands is genetically determined. It is concluded that the presence of these extra bands is not a specific indication for a particular disease or malignant process. The serum of seven patients showed an unusually strong alkaline phosphatase band with a relative mobility amounting to about one-third of that of the liver-type band (2nd fraction group). Specificity for a particular disease could not be established in this group either. In four patients the serum showed an alkaline phosphatase band with an electrophoretic mobility greater than that of the liver-type band (6th fraction group). All of these patients had liver metastases of a primary adenocarcinoma localized in the pancreas or stomach. After the demonstration of this fraction in the serum, the course became progressively worse.