Neutrophil alkaline phosphatase in children with trisomy 21 and their parents

A comparative study of karyotypes and neutrophil alkaline phosphatase (NAP) was carried out for 70 parents (35 couples) of trisomy 21 children and their 35 trisomy 21 children and for 110 control parents (55 couples) and their normal children. In the trisomy 21 families we found a significant increase in NAP: mother P less than 10-4; father P less than 10-4; children P less than 10-9; the NAP level in affected child is approximately equal to the sum of the NAP levels of the two parents (P = 0.80; sigma2 = 5%). In one parent of a trisomy 21 child, a karyotype anomaly was present.     

An enzymatic marker in mothers of trisomy 21 children: neutrophil alkaline phosphatase

Neutrophil alkaline phosphatase (NAP) from 12 mothers of normal children was investigated and the results compared to those of 7 mothers with trisomy 21 offsprings, in an attempt to determine a parental molecular change in this chromosomal abnormality. The biochemical properties of the enzyme were analyzed by the procedures of isoenzyme characterization, i.e. enzyme assays, thermostability, inhibition patterns and slab gel electrophoresis. Immunological properties were determined on 5 samples from normal mothers and on the same sample number of mothers with affected children. In these latter NAP showed characteristics that were to some extent different from the ones of normal controls. The following changes were observed: highly significant loading of membrane and nucleus pellets in NAP activity, poor effect of inhibitors on thermostable component and immunodepletion measured by a significant decrease of the normal affinity for antiliver and antiplacental alkaline phosphatase antisera. These findings are discussed in the light of our knowledge of alkaline phosphatase isoenzymes.     

Heat resistance,immunological and quantitative changes of neutrophil alkaline phosphatase in trisomy 21 pregnancies

Summary Neutrophil alkaline phosphatase (NAP) was analysed in 25 pregnant women with trisomy 21 foetuses whose chromosomal aberration was recognized by cytogenetic study after amniocentesis. Enzyme investigation was performed at 20–22 weeks of gestation using cytochemical and biochemical techniques. Twenty-nine women at the same stage of normal pregnancies were selected as controls. In parallel, each mother was karyotyped. Ten subjects from each series underwent biochemical and immunological investigation: measurement of enzyme levels, thermostability study and immunological tests with alkaline phosphatase isoenzyme antibodies. NAP from pregnant women with trisomy 21 foetuses was characterized by: (1) a lower rate of enzyme activity, (2) a large amount of heat-stable enzyme (T=56°C for biochemical assays, T=85°C for cytochemical tests), and (3) a marked loss of liver antigenicity. These findings suggest the presence in trisomy 21 pregnancies of a non-specific alkaline phosphatase isoenzyme which appears as an enzyme marker in maternal circulating neutrophils.     

Dermatoglyphic studies in the parents of trisomy 21 children I. Distribution of dermatoglyphic discriminants

A sample of 312 parents of a child with complete trisomy 21 (168 mothers and 144 fathers) has been compared with 295 parents of non-mongol children (61 mothers and 134 fathers) with respect to distribution of individual dermatoglyphic discriminant scores. Selection of dermatoglyphic traits as well a weightings have been based on the discriminant function, constructed for normal controls against cytogenetically diagnosed trisomy 21 mosaics. The results indicate that the proportion of individuals with an increased chance of mosaicism is appreciably greater in a sample of both the mothers and the fathers of mongol children, as compared with the parents of non-mongol children. For D greater than + 3.00, including also the overlap range values, it is, on the average, twice as high as in the control parents, while for the D values greater than + 4.00, strongly indicative of mosaicism, it is about five times higher than in control parents. This is so in spite of the fact that all parents, who had previously been cytogenetically tested and diagnosed as mosaics, were not included in this sample. Although the meaning of these results cannot yet be completely understood, they justify the extension of the use of dermatoglyphic discriminants in studies on parental mosaicism in trisomy 21.     

Grandmaternal age at birth of parents of children with trisomy 21

Summary The authors investigated the age of the parents and grandmothers of 262 children with simple trisomy 21. In cases in which the mother was under 30, the mean grandmaternal age was higher than that of the controls. This might mean that some of these cases, being the children of old mothers, began their lives as trisomic zygotes.The authors assume that not only maternal but also paternal mosaicism might be significant. They evaluate their results in light of genetic counseling and in consideration of practical conclusions that can be used in prenatal genetic diagnosis.     

Cytochemical studies of rat liver glycogen and alkaline phosphatase under the effect of hepatocarcinogens.

Cytochemical changes of glycogen and alkaline phosphatase were studied under sequential effect of p-dimethylaminoazobenzene (DAB) feeding and CCl4 injections. It has been found that in liver cells of experimental animals, the concentration of glycogen and the activity of alkaline phosphatase were decreased.     

Ontogeny of human neutrophil granulocyte alkaline phosphatase

Human embryonic neutrophils (N) in the liver (from 8.5 mm crown-rump length) are alkaline phosphatase (AP) negative during the first trimester of pregnancy. Early bone marrow granulocytes (from eleventh to sixteenth weeks of gestation) behave similarly. Only a small percentage of slightly AP positive cells could be found. Occasional cells with strong NAP reaction appear in the second trimester. NAP positivity greatly increases in the third trimester and term-babies have a somewhat higher than normal NAP activity in circulating blood. Unlike NAP reaction, naphthol-AS-D-chloroacetate esterase and peroxidase reactions are positive even in the earliest (AP negative) neutrophils.     

Comparative biochemical studies of placental alkaline phosphatase in animals (author's transl)]

Biochemical properties of alkaline phosphatase (ALP) from placenta were compared between man, dog, cat, rabbit and cattle. 1) Optimum pH of the enzyme was essentially identical through the species of the animals but the inhibition of L-phenylalanine was clearly demonstrable with human ALP but little with that of other animals. 2) ALP of human placenta was not inactivated by heating at 65 degrees C for 15 min. but one of the other animals was thermolabile. Such thermostability of human placental ALP almost disappeared after treatment with EDTA, suggesting that the divalent metal ions were required for the thermostability. 3) Activities of placental ALP were inhibited by cationsurfactants in human and rat but not in the other animals, while the inhibition by DOC-Na, an anion-surfactant, was seen only in human. 4) The affinity to beta-glycerophosphae of placental ALP was seen only in human.     

Cytochemical and biochemical determination of acid phosphatase activity in yeasts]

Optimal conditions of the cytochemical assay for acid phosphatase in protoplasts and whole cells of S. cerevisiae have been described. Dimethyl sulfoxide was used to increase the permeability of the yeast cell envelope. In the yeast cells, grown up to the end of the exponential phase, acid phosphatase is shown to be located mainly in the central vacuole and on the cell envelope surface. A considerable activity of acid phosphatase is demonstrable on the surface of the plasma membrane and within adjacent vesicles that represent, presumably, part of the endoplasmic reticulum. Acid phosphatase can be considered as a marker enzyme for yeast cell vacuoles.     

Effects of uric acid in aqueous phase on neutrophil alkaline phosphatase

In vitro effects of uric acid (2-6-8 trioxypurine) on purified human neutrophil alkaline phosphatase were studied. A marked activation of the enzyme catalyzed reaction is observed. This activation is dose and pH dependent and not influenced by dialysis. Uric acid can form a stable complex with alkaline phosphatase, whose biochemical characteristics (heat stability, reactivity towards some inhibitors) are significantly modified.     

Cytochemical localization of alkaline and acid phosphatase in human vanishing bone disease

This report is the first cytochemical investigation of vanishing bone disease "Gorham's Disease" (Gorham and Stout 1955). The ultrastructural localization of non-specific alkaline phosphatase and of specific and non-specific acid phosphatase activity was studied in slices of tissue removed from a patient with this rare disorder. Sodium beta-glycerophosphate and phosphorylcholine chloride were used as substrates. Alkaline phosphatase was present around the plasma membranes of osteoblasts and associated with extracellular matrix vesicles in new woven bone. This is consistent with the proposed role for this enzyme (Robison 1923) and for matrix vesicles (Bonucci 1967) in the mineralization of bone (Bernard and Marvaso 1981). Concentrations of specific secretory acid phosphatase reaction product in the cytoplasm of degenerating osteoblasts may contribute to the imbalance between bone formation and resorption. Osteoclasts, while few in number, showed non-specific and specific acid phosphatase activity. The Golgi apparatus and heterophagic lysosomes of mononuclear phagocytes were rich in non-specific acid phosphatase. This was also present in the Golgi lamellae and lysosomes of endothelial cells. Acid phosphatase cytochemistry suggests that mononuclear phagocytes, multinuclear osteoclasts and the vascular endothelium are involved in bone resorption in this disease.     

In situ biochemical studies of intestinal alkaline phosphatase in normal and phosphate-depleted rats by microdensitometry

A quantitative microdensitometric study has been designed to characterize in situ intestinal brush border-bound alkaline phosphatase of rat duodenal villosities. Intestinal slices were incubated with beta-glycerophosphate as substrate. Free phosphate liberated was precipitated in presence of a lead reagent as lead sulfide. The precipitate was quantified in situ by scanning and integrating microdensitometry. Kinetic parameters of the reaction were determined at 37 degrees C, pH 8.8, in the middle part of the villosities. Apparent Michaelis constant (Km) for beta-glycerophosphate was found to be 8.16 +/- 0.56 mM (mean +/- S.E.). Maximal enzyme activation was obtained at pH 8.5. Maximal inhibition of enzyme activity was observed in the presence of L-phenylalanine (30 mM) or theophylline (5 mM). Along the villosity axis, enzyme activity rose from the crypt up to the midportion of the villosity and finally decreased at the tip region. In phosphate-depleted rats, enzyme activity was increased in all portions of the villosity, with conservation of the same activity gradient. In this situation, kinetic analysis showed a marked decrease of Km, i.e. 4.56 +/- 0.39 mM (mean +/- S.E.) as compared to normal rats.     

Cytochemical localization of alkaline phosphatase in the cell membrane ofDictyostelium discoideum amebae

Histochemistry and Cell Biology - We demonstrated that alkaline phosphatase was localized on the cell membrane ofDictyostelium discoideum amebae and on isolated plasma membranes. The enzyme...