Detection of Regan variant type of alkaline phosphatase isoenzyme in liver tissue of Indian childhood cirrhosis

Alkaline phosphatase (ALP) isoenzyme composition was studied in sera and liver from patients with Indian childhood cirrhosis (ICC). A typical pattern consisting of a fast-moving anodal preliver band with slower moving diffuse liver and placental bands followed by an intestinal band was consistently observed in sera of patients in all stages of ICC and in pregnant mothers of index ICC patients. ICC liver ALP was relatively heat-stable and inhibited by L-phenylalanine and L-leucine. The isoenzyme also had similar immunological determinants to placental ALP and adult intestinal ALP isoenzymes. Total serum ALP isoenzyme and its heat-stable component progressively increased in concentration from early to advanced stages of the disease suggesting that the diseased liver in ICC is the source of the abnormal isoenzyme.     

Intestinal alkaline phosphatase in patients with chronic renal failure

Because of the suggestion that intestinal alkaline phosphatase was elevated in the serum of patients with chronic renal failure, we studied the serum of 42 patients undergoing hemodialysis with elevated enzyme activity. Using a sensitive and specific electroimmunoassay for the intestinal isoenzyme, 26 of 42 serum samples were positive, compared with 3 of 25 samples obtained from hospitalized patients with elevated phosphatase activity. The fractional amount of this isoenzyme was also higher, ranging from 1.5% to 41% of the total serum phosphatase, compared with 0.1%-1.2% in control sera. Kidneys removed during transplantation or postmortem contained a membranous phosphatase with immunologic activity identical to the intestinal isoenzyme in 5 of 6 patients. This enzyme accounted for 8%-21% of the total kidney phosphatase activity. By morphology the immunoreaction was localized to the apical membranes of the collecting tubules. Thus, the kidney is the likely source of the observed increase in serum intestinal-type phosphatase activity noted in patients with chronic renal failure. An elevation in the intestinal isoenzyme rather than the presence of early metabolic bone disease or hepatic disease should be considered in renal failure patients with mildly elevated (up to 50% over normal) total serum alkaline phosphatase.     

Serum alkaline phosphatase in adult coeliac disease

The total alkaline phosphatase levels were determined in 118 patients with adult coeliac disease, 65 of whom had evidence of osteomalacia.

The secretor and blood group status, intestinal isoenzyme, and liver alkaline phosphatase played no significant part in the levels of serum alkaline phosphatase found.

There was a significant correlation between the levels of serum alkaline phosphatase and the presence of osteomalacia.

     

胆汁型碱性磷酸酶同工酶在恶性肝外胆道阻塞诊断中的价值

目的 探讨胆汁型碱性磷酸酶同工酶在恶性肝外胆道阻塞论断中的价值。方法 用改良琼脂糖电泳对30例健康体检者和105例肝胆疾病患者血清中的碱性磷酶同工酶（ALP）进行分离和定量分析。结果 恶性肝外胆道阻塞的胆汁型ALP显著高于非恶性肝外胆道阻塞、肝内梗阻性黄疸以及原发性肝癌,正常体验者血清中不存在胆汁型ALP;若以100U／L的胆汁型ALP区分恶性肝外胆道阻塞和其他肝胆疾病,则它对恶性外胆道阻塞的诊断灵敏度为82．9％,特异性为95％,阳性预示值为85．3％,阴性预示值为94．1％,实验总有效率为91．9％。结论 胆汁型ALP可作为恶性肝外胆道阻塞的有用诊断指标。     

Role of secondary hyperparathyroidism and liver function in hyperamylasemia in chronic renal failure

Elevated values of pancreatic-type amylase activity in serum were found in 59% of patients with liver cirrhosis not complicated with renal failure, in 67% of patients with chronic renal failure not complicated with hepatopathy and in 95% of patients with chronic renal failure complicated with hepatopathy. In all the three groups, a significant positive correlation was found between the pancreatic-type amylase and intestinal isoenzyme of serum alkaline phosphatase which is an asialoglycoprotein. However, in pancreatitis a prevalence of an increase in pancreatic-type amylase with respect to intestinal alkaline phosphatase was found. A multivariate analysis showed that in chronic renal failure not complicated with hepatopathy, and in chronic renal failure complicated with chronic liver disease, the changes in calcium homeostasis and also the liver disorder, respectively, contribute significantly to the above-normal values for pancreatic-type amylase.     

Intestinal alkaline phosphatase in the diagnosis of liver disease.

Alkaline phosphatase isoenzymes have been studied by acrylamide gel disc electrophoresis in 76 patients with liver disorders comprising 15 with an extrahepatic lesion, 53 with an intrahepatic lesion, and eight patients who had features of both intra- and extrahepatic disease. No intestinal band was found in the 15 cases of extrahepatic liver disease, in marked contrast to the patients with intrahepatic lesions in whom an intestinal band was found in 45% of cases. The intrahepatic group was heterogeneous, a high incidence of intestinal bands being found in patients with cirrhosis of the liver. It is concluded that where a raised serum alkaline phosphatase is found in a patient with jaundice, and a gut band is present on electrophoresis, the lesion is likely to be intrahepatic.     

Changes in neutrophil alkaline phosphatase patterns in a case of chronic myelomonocytic leukemia

In neutrophils from a 75-year-old woman suffering from chronic leukemia, an abnormal alkaline phosphatase (ALP) was observed, characterized by a significant increase in neutrophil alkaline phosphatase (NAP) activity, associated with an ectopic expression of two isoenzymes: a thermolabile ALP similar to the early placental form (or non-Regan variant), and a heat-stable isoenzyme closely related to the Nagao isoenzyme. The presence of these oncodevelopmental NAP isoenzymes in a myeloproliferative syndrome has previously not been reported.     

Regulation of alkaline phosphatase expression in human choriocarcinoma cell lines.

The coincident expression of two structurally distinct isoenzymes of human alkaline phosphatase was demonstrated in two independently derived gestational choriocarcinoma cell lines. These proteins were shown to have enzymatic, antigenic, and physical-chemical properties resembling those of isoenzymes from term placenta and adult liver. The regulation of these isoenzymes has been studied during the exposure of both cell lines to 5-bromodeoxyuridine and dibutyryl cyclic AMP. The responses of the alkaline phosphatase isoenzymes to these agents have also been compared with the response of another protein phenotypic to placenta, the alpha subunit of chorionic gonadotropin. The results show that (i) the separate structural genes coding for placental and liver alkaline phosphatases are regulated in a noncoordinate fashion; (ii) both alkaline phosphatase genes respond independently of the alpha subunit; and (iii) the induction of the placental type isoenzyme occurs via at least two independent pathways.     

Evaluation of postprandial serum bile acid response as a test of hepatic function

Commercial assays for serum bile acids (SBA) have made this measurement practical. The purpose of this study was to examine the utility of SBA measured every 30 min after a standardized meal in controls and in patients with acute viral hepatitis, cholestasis, and anicteric cirrhosis. In five controls, repeated examination of the area under the bile acid curve (AUC) was not statistically different, whereas the fasting and 2-hr postprandial levels were significantly different. In the group of patients with anicteric cirrhosis, AUC identified disease in 18/20 using total serum bile acids (TSBAs) and in 15/20 using cholylglycine (CG). AUC can be calculated from three samples obtained at 0, 60, and 120 min without losing the sensitivity achieved with seven serial samples. SGOT, alkaline phosphatase, and serum albumin were compared for sensitivity to the total SBA response curve in 20 patients with anicteric cirrhosis. SGOT and alkaline phosphatase identified only 50% and 55% as abnormal and serum albumin was less sensitive. Using total SBA, combining the fasting level and AUC identified 100% as abnormal; using CG, 85% of these patients were detected. As a stepwise cost-effective approach, the fasting level of SBAs can identify most patients with anicteric liver disease. In cases with normal fasting levels where liver disease is suspected, the three-point AUC determination may identify additional patients.Supported in part by a grant from the Diagnostic Division, Abbott Laboratories, North Chicago, Illinois.     

Electrophoretic separation of alkaline phosphatase isoenzymes in synovial fluid and serum from patients with rheumatoid arthritis

Summary The alkaline phosphatase enzyme in both serum and synovial fluid from 28 cases of rheumatoid arthritis and from the serum of 30 controls was measured. The enzyme was further studied by separating its isoenzymes to clarify their origin in both synovial fluid and serum of 10 patients with elevated level of the enzyme in their sera. The level of the enzyme in serum was elevated in 37% of patients confirming previous reports on that point. The most abundant isoenzyme in the synovial fluid (66.9%) was found to be bone in origin while in serum the most abundant isoenzyme was found to be hepatic (60.5%). This may be responsible for increased bone turn-over in rheumatoid joints whether in formation or resorption.     

The accuracy of alkaline phosphatase isoenzyme determination

Alkaline phosphatase isoenzyme determination (APID) is in common use despite evidence suggesting that the results correlate poorly with actual sites of disease. To assess the predictive value of this test in clinical practice, 99 APIDs performed on 94 patients were identified and the patients' charts were reviewed. Results of APID were compared with actual patient diagnoses as determined by other means. The liver isoenzyme fraction was not very accurate in predicting the presence of liver disease (positive predictive value 68%). In contrast, the bone isoenzyme fraction was insensitive (56%) but a positive test predicted bone disease well (positive predictive value 93%). The association of elevated transaminases with elevated alkaline phosphatase on a chemistry profile was as useful as APID in identifying liver disease, suggesting that APID should not be done in this setting. Using this information, APID can be helpful in the assessment of an ill patient with an elevated alkaline phosphatase.     

Comparison of serum bile acids with standard liver function tests in the diagnosis of liver disease

Postprandial sera of seventy patients with liver disease (hepatitis 30, cirrhosis 19, liver cancer 21) were analysed for total serum bile acids. The mean values observed in hepatitis (169.0 mumol/L), cirrhosis (112.15) and liver cancer (86.44) were significantly higher (p less than 0.001) than in normal (19.45). The frequency of abnormal bile acids was greater than that of the standard liver function tests except for alkaline phosphatase in liver cancer.     

Perspectives on alkaline phosphatase isoenzymes

Since 1959, electrophoretic technics have ushered in the era of isoenzymes with a proliferation of methods and new findings. This is an attempt to develop a perspective on alkaline phosphatase isoenzymes from both fundamental and applied points of view.Thus, in addition to the bone source, isoenzymes of alkaline phosphatase from liver, intestine and placenta have now been found to contribute importantly to the serum, either individually, or in combination. It is now possible to distinguish each of these from the others in mixtures and to quantitate them by either a combination of specific inhibitors and heat inactivation or urea denaturation or by the employment of a variety of electrophoretic technics in which isoenzyme bands can be identified by their sensitivity to specific inhibitors or their reactivity to specific anti-serums.Particularly helpful in the fractionation of these isoenzymes has been the use of organ-specific inhibitors such as L-phenylalanine and L-homoarginine. In turn, their study has provided new insights into the mechanism of uncompetitive inhibition.The appearance of new forms of alkaline phosphatase during development and an appreciation of developmental control mechanisms has been paralleled by hormone enhancement of activity in cells (HeLa) growing in culture. The role of alkaline phosphatase in fat absorption and in placental function has now become a subject of interest, and the interrelationship with genetic factors such as blood groups has been recognized. The appearance of new forms during development is now accepted.The classic question of whether or not the liver is able to generate a major contribution of alkaline phosphatase to the circulation is still being investigated.Finally, an exciting direction is the study of the recently discovered placental forms of alkaline phosphatase in the tumor tissue, body fluids and serum of certain cancer patients. From the clinical point of view, tumor alkaline phosphatase may explain certain hyperphosphatasemias in problems of differential diagnosis, and from the biological perspective, this phenomenon can be studied profitably as an example of embryonic gene activation in cancer.     

Clinical value of serum alkaline phosphatase isoenzyme estimations in the elderly.

The value of the estimation of liver and bone isoenzyme of alkaline phosphatase in a series of 500 admissions to a geriatric unit is described. A raised total alkaline phosphatase was found in 40 patients and this was due to raised levels of the bone isoenzyme in about two-thirds of these. Its value in diagnosis of treatable bone disease is emphasized.     

Adult hypophosphatasia and a low level of red blood cell thiamine pyrophosphate

OBJECTIVE: To report the first adult case of hypophosphatasia and absence of intestinal alkaline phosphatase (ALP) isoenzymes associated with a low level of red blood cell thiamine pyrophosphate. METHODS: We describe the clinical manifestation and laboratory findings in our patient and discuss underlying factors that potentially contribute to her condition. RESULTS: A 33-year-old Vietnamese-American female was referred for a long history of low levels of serum ALP and absence of intestinal ALP isoenzyme. She had a normal level of urinary phosphoethanolamine and a high level of plasma pyridoxal-5p-phosphate. She was found to have a low level of red blood cell thiamine pyrophosphate. CONCLUSION: Our adult case of hypophosphatasia presented with an absence of intestinal ALP isoenzyme that might result in decreasing the absorption of thiamine in the intestinal tract. Therefore, the thiamine level should be considered in hypophosphatasia with absence of intestinal ALP isoenzyme.     

Cancer-associated isoenzyme of serum galactosyltransferase.

Galactosyltransferase activity was assayed in sera from 58 patients with various types of cancer. On discontinuous polyacrylamide gel electrophoresis a slow-moving peak of galactosyltransferase activity (isoenzyme II) was found to be present in the serum of 43 of these patients in addition to the major isoenzyme I. Isoenzyme II was found in only 2 of 39 patients with various nonmalignant disorders and was not detected in the serum of 22 normal control subjects. There was no correlation between the presence of this electrophoretically distinct isoenzyme and total serum galactosyltransferase activity, alkaline phosphatase, levels of carcinoembryonic antigen, or blood type. However, patients with widespread metastases had significantly higher isoenzyme II levels than those with no metastases or with limited local spread. Further studies will be necessary to evaluate the clinical usefulness of this serum galactosyltransferase isoenzyme in the diagnosis and monitoring of patients with neoplastic disease.     

Extracellular alkaline phosphatase in the airways of the rabbit lung

In an attempt to characterize the soluble alkaline phosphatase in rabbit lung, we have compared its activity to that of intestine, liver, bone, kidney, spleen and serum. The pulmonary alkaline phosphatase consists of isoenzymes with isoelectric points (pI) at pH 5. 0, 5. 5 and 5. 8 which are distinct from the soluble isoenzymes of the other tissues and, by this criterion, appear to be organ specific. The isoenzyme with a pI of 5. 8 has an apparent molecular weight of 185, 000 daltons and is found almost exclusively extracellularly in the airways. The isoenzyme with a pI of 5. 5 (mol. wt. = 185, 000 daltons) is distributed more equally between pulmonary tissue and the airways, and the isoenzyme of pI equal to 5. 0 (mol. wt. = 210, 000 daltons) is located entirely within the lung tissue. The isoenzymes present in the airways are closely related in spite of their different isoelectric points. In addition to their apparent molecular weights, they have similar apparent K_m values and thermostabilities. The difference in isoelectric points is probably due to different sialic acid contents since digestion of the two alkaline phosphatases in the airways with neuraminidase gives rise to a single form with a pI of 7. 6.     

Prevalence of hepatitis in early syphilis among an HIV cohort

To investigate the prevalence of syphilitic hepatitis among a group of HIV-infected patients we performed a cross-sectional observational study of consecutive HIV-infected patients with early syphilis attending University Hospital Birmingham between 1 January 2005 and 31 August 2008. The AIDS Clinical Trials Group grading for abnormal liver enzymes was used to identify hepatitis. A total of 62 HIV-infected patients were diagnosed with early syphilis during the study period. Twelve (19.3%) of them demonstrated abnormal liver enzymes consistent with syphilitic hepatitis involving raised levels of alanine aminotransferase, aspartate transaminase, alkaline phosphatase or gamma-glutamyl transferase (GGT). Grade 3 hepatotoxicity was observed among five patients. None of the patients with syphilitic hepatitis had grade IV hepatitis or abnormal bilirubin levels. Liver biopsy was not carried out in any of the patients, and following completion of treatment of syphilis all abnormal liver enzymes returned to normal levels after a median of 16 weeks. Exclusion of syphilis must be considered when investigating hepatic disease in HIV-infected patients.     

Phosphatases XII. Isoenzymes of alkaline phosphatase and radionuclear investigation (85Sr) of patients with neoplastic affection of the skeleton.

In a group of 30 patients with neoplastic processes, 13 were found to have a significantly increased serum alkaline phosphatase activity. This finding correlated with the results of investigation with 85Sr in 7 patients, but owing to a concomitant hepatal symptomatology, it proved of differential diagnostic value in only one of them. On the other hand, the activity of bone isoenzyme of alkaline phosphatase was significantly altered in 15 patients. In 14 of them the increase in bone isoenzyme activity corresponded to an X-ray and a radionuclear finding of a tumor process in the bones. This activity was within the normal range of values in only one patient with a positive result of the 85Sr investigation. An agreement between the results of determination of bone isoenzyme activity of alkaline phosphatase and those of radionuclear investigations was found in 27 patients. In addition, a correlation was established between the increased activity of bone isoenzyme and that of intestinal isoenzyme of alkaline phosphatase. Enzyme investigation can be suitably utilized, alongside radionuclear examination, for early detection of a bone process.     

Characterization of elevated plasma alkaline phosphatase activity in genetically obese mice

Alkaline phosphatase activity in obese mice ($\text{C57BL}\text{6J}\text{ob}\text{ob}$) was significantly increased from 18 to 63 weeks of age when compared to that of their lean controls ($\text{C57BL}\text{6J}\text{+/?}$). In 5 week old animals, the earliest age examined, the circulating activity of alkaline phosphatase was similar in both obese mice and their lean counterparts. To characterize the circulating alkaline phosphatase activity in the obese mouse and its lean counterpart, the response of the enzyme to fasting, various inhibitors, heat inactivation, and urea denaturation was examined and compared. L-homoarginine and L-p-bromotetramisole inhibited to a large extent the circulating activity of alkaline phosphatase in both obese mice and their lean controls in the fed state, while L-phenylalanine had essentially no effect. Even though the response of alkaline phosphatase in plasma to several inhibitors was similar, the rate of denaturation by urea of enzyme activity in plasma was significantly slower in obese mice than in their lean controls in the fed state. While the rate of inactivation of alkaline phosphatase activity in plasma for the initial two minutes at 56°C was similar in obese mice and their lean counterparts, the subsequent rate of heat inactivation was significantly slower in the plasma from obese mice. Thus, both obese and lean mice in the fed state have a circulating activity of alkaline phosphatase in plasma with a greater contribution from a skeletal isoenzyme and a lesser one of intestinal origin. Even though the contribution of the bone isoenzyme could not be completely differentiated from that of liver, the circulating alkaline phosphatase activity in the obese mouse has a component of greater stability to both urea denaturation and heat inactivation, presumably hepatic in origin.