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PubMed1985

The effect of jejunectomy on alkaline phosphatase activity in the ileum.

The activity of alkaline phosphatase activity in the small intestinal wall was studied in dogs after jejunectomy. The observations were made 3, 6, 8 or 9 and 12 weeks after operation. The studies aimed to obtain some information about the functional adaptation processes of the remaining intestinal segments. The enzyme activity in homogenates of duodenal and ileal mucosa was determined. Parallel interferometric measurements in the brush border and on the surface of the absorptive cells were performed. The results obtained indicate that after temporary reduction (especially 6 weeks postoperatively) a gradual rise of the alkaline phosphatase activity both in homogenates and in the brush border of the intestinal remnants took place. Several times repeated biopsies confirmed the ability of the intestinal segments (duodenum and distal ileum) significant increase in enzyme activity over the normal (control) level was observed.

Alkaline Phosphatase↗
PubMed1988

Primary sclerosing cholangitis with normal serum alkaline phosphatase activity.

We report 12 cases of primary sclerosing cholangitis (confirmed by cholangiography) in which the serum alkaline phosphatase activity was normal. The enzyme activity remained normal during follow-up in 7 cases and fluctuated in 5 cases (it returned to normal in 4). The presence of advanced histologic stage (fibrosis/cirrhosis) with marked cholangiographic changes in 4 patients establishes that cirrhotic-stage primary sclerosing cholangitis can occur without a concomitant increase in serum alkaline phosphatase activity. Therefore, primary sclerosing cholangitis may exist in an occult state without symptoms or increase in serum alkaline phosphatase activity. Our findings suggest that primary sclerosing cholangitis may be more prevalent than realized, especially in patients who have inflammatory bowel disease. A normal value for serum alkaline phosphatase activity should not preclude further investigation for primary sclerosing cholangitis in patients with inflammatory bowel disease when symptoms or signs suggest liver disease.

Adult↗
PubMed2006

Acute effect of tea, wine, beer, and polyphenols on ecto-alkaline phosphatase activity in human vascular smooth muscle cells.

Alkaline phosphatase (ALP) is an ecto-enzyme widely distributed across species. It modulates a series of transmembranar transport systems, has an important role in bone mineralization, and can also be involved in vascular calcification. Polyphenol-rich diets seem to have protective effects on human health, namely, in the prevention of cardiovascular diseases. We aimed to investigate the effects of polyphenols and polyphenol-rich beverages upon membranar alkaline phosphatase (ecto-ALP) activity in intact human vascular smooth muscle cells (AALTR). The ecto-ALP activity was determined at pH 7.8, with p-nitrophenyl phosphate as the substrate, by absorbance spectrophotometry at 410 nm. Cell viability was assessed by the lactate dehydrogenase (LDH) method, and the polyphenol content of beverages was assessed using the Folin-Ciocalteu reagent. All polyphenols tested inhibited ecto-ALP activity, in a concentration-dependent way. Teas, wines, and beers also inhibited ecto-ALP activity, largely according to their polyphenol content. All tested compounds and beverages improved or did not change AALTR cell viability. Stout beer was an exception to the described behavior. Although more studies must be done, the inhibition of AALTR ecto-ALP activity by polyphenolic compounds and polyphenol-containing beverages may contribute to their cardiovascular protective effects.

Alkaline Phosphatase↗
PubMed1987

Comparison of CA 125 and placental alkaline phosphatase as ovarian tumor markers.

The serum concentrations of CA 125 and placental alkaline phosphatase were analyzed in 16 patients with ovarian cancer. Increased serum levels of CA 125 and placental alkaline phosphatase were observed in 75% and 50% of the cancer patients, respectively. The serum levels of these tumor markers were not correlated, supporting their distinct antigenic nature. CA 125 seems to be a more promising tumor marker for ovarian cancer than placental alkaline phosphatase.

Aged↗
PubMed1985

pH-dependent conversion of liver-membranous alkaline phosphatase to a serum-soluble form by n-butanol extraction.

Alkaline phosphatase released from rat liver plasma membrane under usual conditions was electrophoretically not identical with a soluble form in serum which was derived from the liver. The liver-membranous alkaline phosphatase, however, was converted to the serum-soluble form when the liver plasma membrane was treated with n-butanol under the acidic conditions lower than pH 6.5. Such pH-dependent conversion of the enzyme was not observed in plasma membrane of rat ascites hepatoma AH-130 cells. The converting activity for alkaline phosphatase was detected not only in plasma membrane but also in lysosomal membrane of rat liver.

1-Butanol↗
PubMed1994

[Serum alkaline phosphatase levels in pregnancy].

Serum levels of total alkaline phosphatase increase during pregnancy but the presently available methods are not very precise. We used the CHEM 1 Bayer Diagnostic test in all the consecutive patients admitted to our unit between June 1 and October 16, 1990. Exclusion criteria were twin pregnancies, pruritus, liver disease or parasitosis. A multifactorial analysis was used to discriminate between general, obstetric, pathologic and drug parameters. There were 373 serum samples, 91% were obtained during the last three months of pregnancy. The mean serum alkaline phosphatase level was 68.2 U/l and 75.9 U/l during the first two trimesters respectively and rose to 126.7, 178.8 and 234 U/l during the last three months respectively. The elevation was greater in cases of vomiting during the first trimester, alpha-methyldopa intake. It was less after hypodroxyapatite intake and was positively correlated with weight gain. Age, parity, pregestational weight, neonatal weight, other pathologies and other drug intake did not affect the results. Knowledge of these physiological levels will be useful for evaluating most liver diseases occurring during pregnancy. Assay of the enzyme fractions would be ordered secondarily.

Adolescent↗
PubMed1984

[Functioning tumor of lung, producing non-Regan type of alkaline phosphatase].

There are various functioning tumors in human organs and sometimes it is very difficult to make a diagnosis in the early stage of the disease. Functioning tumors of the lung which produce alkaline phosphatase can be divided into two groups, the Regan type and the non Regan type. Our patient showed a high blood level of alkaline phosphatase without hepatic functioning abnormality and hepatomegaly. Nevertheless, we concluded that this alkaline phosphatase was isoenzymatically of hepatic origin. The type of alkaline phosphatase was very similar to that of Sella's lung cancer patient. Autopsy of our patient revealed moderately differentiated lung adenocarcinoma similar to Sella's report, suggesting that the alkaline phosphatase was of the non-Regan type.

Adenocarcinoma↗
PubMed1993

Construction, characterisation and kinetics of a single chain antibody recognising the tumour associated antigen placental alkaline phosphatase.

The murine monoclonal antibody H17E2 recognises placental alkaline phosphatase (PLAP), an antigen present in the human term placenta and also expressed by many tumours. The antibody is of value in both immunoscintigraphy and radioimmunotherapy in testicular and ovarian cancer. The small size of genetically engineered single chain antibodies (SCAs) should give diagnostic and therapeutic advantages of improved tumour penetration and increased blood clearance compared to IgG. Employing recombinant DNA techniques a SCA based on H17E2 has been expressed in Escherichia coli and has been shown to bind placental alkaline phosphatase specifically. When administered to nude mice bearing human tumour xenografts, the H17E2 SCA effectively localised to tumour whilst a co-administered non-specific SCA did not. H17E2 SCA achieves tumour: blood ratios that are superior to those achieved with whole IgG, probably owing to its rapid blood clearance. We conclude that the H17E2 SCA is suitable for further investigation as an agent for clinical imaging and therapy. Additionally, the SCA can also be used for the construction of antibody based fusion proteins to target other effector functions to tumour cells.

Alkaline Phosphatase↗
PubMed1997

Dependence of divalent metal ions on phosphotransferase activity of osseous plate alkaline phosphatase.

Kinetic evidence for the role of divalent metal ions in the phosphotransferase activity of polidocanol-solubilized alkaline phosphatase from osseous plate is reported. Ethylenediamine tetreacetate, 1,10-phenanthrolin, and Chelex-100 were used to prepare metal-depleted alkaline phosphatase. Except for Chelex-100, either irreversible inactivation of the enzyme or incomplete removal of metal ions occurred. After Chelex-100 treatment, full hydrolase activity of alkaline phosphatase was recovered upon addition of metal ions. On the other hand, only 20% of transferase activity was restored with 0.1 microM ZnCl2, in the presence of 1.0 M diethanolamine as phosphate acceptor. In the presence of 0.1 mM MgCl2, the recovery of transferase activity increased to 63%. Independently of the phosphate acceptor used, the transferase activity of the metal-depleted alkaline phosphatase was fully restored by 8 microM ZnCl2 plus 5 mM MgCl2. In the presence of diethanolamine as phosphate acceptor, manganese, cobalt, and calcium ions did not stimulate the transferase activity. However, manganese and cobalt-enzyme catalyzed the transfer of phosphate to glycerol and glucose.

Alkaline Phosphatase↗
PubMed1991

Progestin regulation of alkaline phosphatase in the human breast cancer cell line T47D.

In T47D breast cancer cell line, progestin (R5020) induces de novo synthesis of an alkaline phosphatase enzyme. Based on inhibitor profiles and antigenic specificity, it is apparent that this enzyme belongs to the class of membrane-associated tissue-unspecific alkaline phosphatases. Enzyme induction was uniquely specific to progestins and not altered by other steroid hormones or synthetic analogues. The progestin induction of the tissue-unspecific alkaline phosphatase was time and dose dependent. The protein synthesis inhibitor cycloheximide blocks the enzyme synthesis and tunicamycin blocks the enzyme activity, showing that the induction was new synthesis of protein in its complete glycosylated form and not activation of a preexisting enzyme. To our knowledge this is the first report of progesterone-induced expression of a tissue-unspecific alkaline phosphatase gene of such magnitude (about 30- to 100-fold) in a progesterone-responsive tissue.

Acid Phosphatase↗
PubMed1989

Effects of synthetic calcium phosphates on the 3H-thymidine incorporation and alkaline phosphatase activity of human fibroblasts in culture.

Gingival fibroblasts were cultured with four different calcium phosphate minerals (hydroxyapatite, whitlockite, beta-tricalcium phosphate, and octocalcium phosphate). 3H-thymidine incorporation into DNA and alkaline phosphatase specific activity were determined after different incubation periods. As a consequence of the phagocytosis of calcium phosphates crystals, we pointed out, compared to control, a stimulation of the rate of 3H-thymidine incorporation and sharp decreases in alkaline phosphatase activity. The magnitude of the alkaline phosphatase activity inhibition was observed to be increased with the solubility of the materials. We propose that the effects of calcium phosphates on alkaline phosphatase and 3H-thymidine incorporation could be calcium-mediated events, resulting from intracellular dissolution of phagocytized materials. We suggest that in vitro determination of 3H-thymidine incorporation and alkaline phosphatase activity, which are highly sensitive tests, could be involved in evaluation procedures of calcium phosphates biomaterials.

Adult↗
PubMed1987

Chemical identification of lipid components in the membranous form of rat liver alkaline phosphatase.

Membranous and soluble forms of rat liver alkaline phosphatase were selectively prepared by extracting microsomes with n-butanol at pH 8.5 and 5.5, respectively, and purified in homogeneous forms by the method previously established (Miki et al. (1986) Eur. J. Biochem. 160, 41-48). When subjected to polyacrylamide gel electrophoresis, the two forms migrated to the same position in the presence of sodium dodecyl sulfate, while the membranous form remained at the top of gels in the absence of the detergent. Treatment of the membranous form with phosphatidylinositol-specific phospholipase C resulted in its conversion to a soluble form with the same electrophoretic mobility even in the absence of the detergent as that of the soluble form extracted at pH 5.5. Automated Edman degradation analysis showed that the two forms have the same N-terminal amino acid sequence up to the 30th residue determined. Chemical analyses of hydrolysates of the two forms by gas-liquid chromatography demonstrated that the membranous form contains palmitic acid, stearic acid, and inositol, while the soluble form contains inositol but is devoid of the fatty acids. Taken together, these results suggest that rat liver alkaline phosphatase is covalently attached to phosphatidylinositol acylated with palmitic acid and stearic acid, which functions as the membrane-anchoring domain of the enzyme molecule.

Alkaline Phosphatase↗
PubMedDate not supplied

Inhibition of alkaline phosphatase activity of boar semen by pentoxifylline, caffeine, and theophylline.

Methyl xanthines have been used frequently as additives to sperm suspensions in order to improve sperm characteristics. The mechanism of action on spermatozoa is generally assumed to be inhibition of sperm phosphodiesterase activity, resulting in elevation of complementary adenosine monophosphate levels in spermatozoa. The present study was designed to examine the effect of methyl xanthines (pentoxifylline, caffeine, and theophylline) on another important enzyme system, alkaline phosphatase, in boar seminal plasma and spermatozoa. Inhibition of sperm alkaline phosphatase could be distinguished from that of seminal plasma by a paradoxical stimulation by pentoxifylline at lower pH values in spermatozoa. Among the three methyl xanthines, theophylline exhibited the most dramatic inhibition of alkaline phosphatase activity and substrate inhibition was observed with increasing concentrations. Each methyl xanthine had a different action on alkaline phosphatase activity at lower pH; theophylline showed the highest inhibition, caffeine inhibition was not related to pH, and pentoxifylline did not inhibit alkaline phosphatase of seminal plasma and, in fact, it stimulated its activity (or that of a phosphatase with lower pH optimum) in spermatozoa. These results indicate another possible mechanism of action of methyl xanthines on sperm and are in agreement with data indicating that methyl xanthines are not specific inhibitors of sperm phosphodiesterase, because clearly, they inhibit alkaline phosphatase activity as well.

Alkaline Phosphatase↗
PubMed1983

Isoenzymes of canine plasma alkaline phosphatase: an investigation using isoelectric focusing and related to diagnosis.

The isoenzymes of canine alkaline phosphatase have been separated by isoelectric focusing on agarose gels. Alkaline phosphatase from normal tissue extracts gave heterogeneous focusing patterns with the following isoelectric points: liver pH 4.3, bone pH 4.0 to 4.9, kidney pH 4.4 to 4.7 and intestine pH 3.6 to 4.6. Plasma alkaline phosphatase isoenzymes were examined in 123 dogs with activities at least twice the normal maximum. The isoenzymes from these plasma samples had multiple bands at pH 4.3 to 4.6 but in 67 per cent of all cases, the predominant isoenzyme, named isoenzyme A, was a single band of isoelectric point pH 3.5. Isoenzyme A occurred in all dogs with diabetes mellitus or Cushing's syndrome and in 93 per cent of animals receiving steroid therapy. Increased activities of the pH 4.3 to 4.6 isoenzymes were more likely to occur in cases of hepatic degeneration.

Alkaline Phosphatase↗
PubMed1981

Intestinal alkaline phosphatase in bile: evidence for an enterohepatic circulation.

The isoenzyme characteristics of alkaline phosphatase in human bile obtained from patients with gallstones have been determined by means of electrophoresis on polyacrylamide gel, both before and after preincubation with neuraminidase, and also by means of inhibition tests with heat, urea, and L-phenylalanine. Bile alkaline phosphatase is shown to be partly secreted by the liver cell, but partly derived from the small intestine. The presence of small-intestinal alkaline phosphatase in bile implies an enterohepatic circulation of this high molecular weight glycoprotein. The significance of this finding is discussed in relation to the mechanism whereby large protein molecules may pass across the plasma membrane of the liver cell.

Alkaline Phosphatase↗
PubMed1994

A continuous spectrophotometric assay for alkaline phosphatase with glycerophosphate as substrate.

We describe a continuous coupled spectrophotometric assay for alkaline phosphatase which uses alpha- or beta-glycerophosphate as substrate, and glycerol dehydrogenase as ancillary enzyme. The glycerol liberated by alkaline phosphatase is determined by measuring the increase in absorbance at 340 nm caused by NADH formation that is combined with glycerol oxidation by the ancillary enzyme. The assay procedure was optimized using a bovine bone extract as alkaline phosphatase source.

Alkaline Phosphatase↗
PubMed1993

Heterogeneity of glycosylphosphatidylinositol-anchored alkaline phosphatase of calf intestine.

A method is described for large-scale purification of glycosylphosphatidylinositol-anchored alkaline phosphatase from intestinal mucosa and chyme to homogeneity. Both enzyme preparations contain approximately 2 mol fatty acid/mol subunit and exhibit a very similar fatty acid composition with octadecanoate and hexadecanoate as prevalent components. No significant differences between native glycosylPtdIns-anchored and hydrophilic alkaline phosphatases from both sources were found regarding Km, Vmax, the type of inhibition and inhibition constants of the amino acids L-leucine, L-phenylalanine, and L-tryptophan. The purified enzymes of both sources yield diacylglycerol and phosphatidic acid, after treatment with phosphatidylinositol-specific phospholipase C (PtdIns-PLC) and glycosylphosphatidylinositol phospholipase D (PLD), respectively. Enzyme preparations of both sources appear as heterogeneous mixtures of five fractions separable by octyl-Sepharose chromatography. Fraction I corresponds to the anchorless enzyme, fractions II-V differ in their susceptibility to phospholipases. Fractions II and IV are completely split by PtdIns-PLC or PLD action, almost 50% of fraction III is split by PtdIns-PLC, while fraction V is resistant. The susceptibility of these two fractions toward the action of PLD is considerably higher. Fatty acid analysis yields molar ratios of fatty acids/alkaline phosphatase subunit of 1.78, 2.58, 2.24, and 3.37 for fractions II, III, IV, and V, respectively. Aggregates of glycosylPtdIns-anchored alkaline phosphatase of all fractions are seen in native PAGE in the presence of Triton X-100. By gel chromatography in the presence of Brij 35, fractions II-V form stable multiple aggregates of dimers and may bind different amounts of the detergent. These data, together with fatty acid analysis, can be interpreted by the following model. Fractions II and IV are tetramers and octamers with two molecules fatty acid/subunit. Fraction III is a tetramer, bearing one additional fatty acid molecule, localized on the dimer. Fraction V is an octamer, containing glycosylPtdIns-anchor molecules with three molecules fatty acids/anchor molecule. The additional fatty acid residue is possibly located on inositol and responsible for the reduced susceptibility to PtdIns-PLC. The similarity of all measured parameters of both enzymes suggests that the glycosylPtdIns-anchored alkaline phosphatase of the mucosa is released into the chyme without changing the anchor molecule constituents.

Alkaline Phosphatase↗
PubMedDate not supplied

Sensitive fluorometric detection of heat-stable alkaline phosphatase from bloodstains for the forensic diagnosis of pregnancy.

Sensitive and simple procedures are established for the forensic pregnancy test from bloodstains. This paper describes new techniques based on heat stability of placental alkaline phosphatase. In this study the total and heat-stable alkaline phosphatase activities were determined using 4-methylumbelliferyl-phosphate as substrate. The ratio of heat-stable alkaline phosphatase to total alkaline phosphatase was calculated. A more simple screening test which was visible by exposure to UV light is described. These may be helpful in the diagnosis of pregnancy from only a slight bloodstain.

Alkaline Phosphatase↗