Alkaline phosphatase activities in human amniotic fluid, chromatographic separation of the foetal intestinal component.

Hydrophilic gel permeation chromatography of 14-36 wk human amniotic fluid on Fractogel columns divides the total alkaline phosphatase (AP) activity in a higher and a lower mol wt zones. Differential inhibition testing, isoelectric focusing, cellulose acetate, agarose and polyacrylamide gel electrophoreses before and after neuraminidase treatment show the higher mol wt zone to be homogeneous and to be made of the higher mol wt foetal intestinal isoenzyme form whereas the lower mol wt zone represents an unresolved mixture of hepatic, placental and lower mol wt foetal intestinal isoenzymes. In the early stages of pregnancy, the activity associated with the higher mol wt zone outweighs by far that of the lower mol wt zone; however from the 24 th week one notes a steady increase in the relative magnitude of this second zone until at the end of the gestation period both zones assume near equal importance albeit within a lower total AP activity. Satisfactory quantitation of the higher mol wt foetal intestinal isoenzyme form in one ml amniotic fluid can be attained after a 3-h chromatography run using p-nitrophenylphosphate as substrate.

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.

Amyloidosis of the joints: evidence that human hip capsules have a unique predisposition for amyloid of the senile systemic type.

Amyloid-containing tissues were sampled from 19 capsules and 10 cartilages from hip, knee and sternoclavicular joints of 16 elderly patients. Heart ventricles from 3 of these patients were also studied. Histochemistry and immunofluorescence were performed and amyloid fibrils extracted from one hip capsule. The results indicate that 9 of 13 hip capsules contained prealbumin-like amyloid fibril protein ASc1, a finding characteristic of senile systemic amyloidosis. The amyloid of 16 out of 17 other joint structures showed no reaction with anti-ASc1 or antisera to 3 other systemic forms of amyloid, indicating that they represent localized forms of amyloid.

In vivo metabolism of human apoprotein A-I-phospholipid complexes. Comparison with human high density lipoprotein-apoprotein A-I metabolism.

The metabolism of apolipoprotein A-I was investigated in healthy young adults. The apoprotein was injected intravenously in one of the four following forms: radiolabelled high density lipoproteins, HDL incubated with labelled apo A-I, labelled A-I-dipalmitoyl- or dimyristoylphosphatidylcholine complexes or free apoprotein A-I. The radioactivity-time curves of high density lipoproteins were followed for 15 days. The kinetic studies demonstrate similar fractional catabolic rates, half-lifes and rates of synthesis. Fractional catabolic rate calculated from plasma data was in reasonable agreement with the value derived from the urine/plasma activity ratio. When free apo A-I was injected, the unusual form of the U/P ratio curve is interpreted as the result of different fates of the injected molecules. This study indicates that the half-life of apo A-I seems not to be affected by the form in which the apoprotein is injected and that kinetics of apo A-I-phospholipid complexes may be used as a valid index of apoprotein A-I/HDL metabolism.

Apoprotein S, a family of human serum lipoprotein polypeptides.

Glucose infusions given to neurological and postsurgical patients in the absence of oral feeding were found to increase the amount of new polypeptides in high density lipoproteins from 3 to 40% of total proteins as compared to 0.1% in normal subjects fed a regular diet. This increase was observed in HDL2 as well as in HDL3 and even in VLDL. Eight polymorphic forms were detected by chromatography, polyacrylamide gel electrophoresis and isoelectric focusing. The partial amino acid sequence of one of these forms is given: the first 26 NH2-terminal residues are identical to the amphipathic helical segment of SAA protein, theoretically responsible for the lipid binding. The role of glucose as the major factor involved in the production of these apoproteins is discussed.

Separation and partial characterization of new apoproteins from human plasma high density lipoproteins.

In four patients receiving parenteral fluids, human plasma high density lipoproteins were obtained by sequential ultracentrifugation and delipidated. Apoproteins were resolved by gel filtration on Sephadex G-200, DEAE-cellulose chromatography, and polyacrylamide gel electrophoresis. Sephadex-Fraction V was unusually large (11--33% compared to 3--7% in normal subjects) and was found to contain seven new apoprotein components of an apparent molecular weight (by SDS gel electrophoresis) between 8000 and 11 000. Amino acid analysis showed that all these peptides had a high glycine and arginine content and a very low content of threonine and valine. Isoelectric focusing gave isoelectric points ranging from 5.00 to 8.00. In two patients injected with L-[1-17C]-leucine, incorporation of radioactivity into these peptides gave specific activities of the same order of magnitude as apo C-II and apo C-III. IT may be postulated that these peptides increased significantly when proteins are deficient in the diet or have low levels in plasma. The structural and functional significance of these peptides remains to be determined.

[Pharmacological suppression of gestation by beta-2-aminoethylisothiourea (AET) in rats]. / Suppression pharmacologique de la gestation par la 2-beta-aminoéthylisothiourée (AET) chez la Ratte

One I.P. injection of 2-beta-aminoethylisothiourea (150 or 200 mg/kg) given to rats on day 14 and eventually also on day 18 of gestation induced a maternal death rate ranging from 0 to 50%, together with frequent (1 dose) or systematic (2 doses) foetal resorption. This type of treatment also impairs further reproductive capacity.