Quantitative determination of the activity of acid peptidases of industrial origin]

Reagent ninhydrine-Cd++, reacts with free alpha and epsilon amino groups of proteins. Horse-heart apomyoglobin was subjected to exhaustive succinylation, rendering the product non reactive to ninhydrine. The succinylglobin was submitted to enzyme digestion at pH 2.0, 4.0, 4.7 and 6.0. The commercially available enzymes contain mainly pepsin-like and chymosin-like enzymes. The enzymatic digests of succinyl-globin contain new free alpha-amino groups reacting with ninhydrin. Enzymatic digestion was performed under various condition (ratio E/S, pH). The results were compared to those obtained with synthetic substrate: PRO-HIS-LEU-SER-PHE(NO2)-NLEU-ALA-LEU-OME. The price of the synthetic substrate used, was more than 100 times the cost of succinyl-globin, thus the use of this substrate is a valuable tool for the quantitative estimation of peptidase activity in commercially available (pepsin, chymosin-like) enzymes.     

Comparison of a natural heparinoid with sodium and calcium heparin for their effect on the inhibitor of activated factor X

Summary The reaction between activated factor X (Xa) and its natural inhibitor (XaI) was accelerated in vitro by both sodium heparin and an heparinoid, which was about 3 times less potent than heparin. The s. c. administration in humans of 5,000 units of sodium and calcium heparin was followed by the detection of a plasma activity potentiating XaI. In the majority of subjects, the heparinoid was not effective. These observations indicate that the use of heparinoids should not be considered as an alternative to heparin in the prevention of thromboembolism.     

Wireless microphone for studies of animal vocalizations.

A microphone collar for obtaining good quality recordings of animal vocalizations is described. An inexpensive, commercially available wireless microphone was modified and mounted on a collar with a hearing-aidbattery pack. The complete assembly weighs 25 g, and is readily accepted by domestic cats.     

An intelligent business forecaster for strategic business planning

In this paper an intelligent business forecaster for strategic business planning is presented. The forecaster is basically a multi‐layered fuzzy rule‐based neural network which integrates the basic elements and functions of a traditional fuzzy logic inference into a neural network structure. It has also been shown to be superior to two commercially available business forecasters in terms of learning speed and forecasting accuracy. This paper presents the architectural design of the intelligent business forecaster and the results of a study that has been carried out to compare its performance with that of the others. Copyright © 1999 John Wiley & Sons, Ltd.     

Wireless microphone for studies of animal vocalizations

Summary A microphone collar for obtaining good quality recordings of animal vocalizations is described. An inexpensive, commercially available wireless microphone was modified and mounted on a collar with a hearing-aidbattery pack. The complete assembly weighs, 25 g, and is readily accepted by domestic cats.     

Comparison of a natural heparinoid with sodium and calcium heparin for their effect on the inhibitor of activated factor X.

The reaction between activated factor X (Xa) and its natural inhibitor (XaI) was accelerated in vitro by both sodium heparin and an heparinoid, which was about 3 times less potent than heparin. The s. c. administration in humans of 5,000 units of sodium and calcium heparin was followed by the detection of a plasma activity potentiating XaI. In the majority of subjects, the heparinoid was not effective. These observations indicate that the use of heparinoids should not be considered as an alternative to heparin in the prevention of thromboembolism.     

Heparin effects on cultured mammalian cells.

Plasmacytoma cells exposed to heparin exhibited zeiotic blebs in the G1 phase, S phase, and early G2 phase. Zeiosis was not seen in mitotic cells. This heparin effect was reversible. Also fibroblasts were sensitive to heparin. After trypsinization of fibroblasts, heparin produced large non-reversible zeiotic blebs in the cells, except in those in mitosis. The primary target for heparin is apparently to be sought among components of the cellular periphery.     

Technische Probleme der Hämoglobin-Elektrophorese im Stärkeblock

Summary A simple apparatus for starch block electrophoresis is described. The cooling element consists of a commercially available cold plate in metal.If oxyhaemoglobin is used, an error in measurement by the instability of the haemoglobin solutions can be reduced by adding small amounts of KCN, not only to the initial haemolysate, but also to the haemoglobin fractions which were eluted.

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Die Arbeit wurde mit Hilfe eines Forschungsbeitrages des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung durchgeführt.

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Wir danken Frl.L. Bargetzi für ihre technische Hilfe bei allen Untersuchungen.     

The use of microtiter plates for the simple and sensitive determination of insulin by an ELISA method

A method of insulin determination using a commercially available ELISA kit was modified for use in microtiter plates. The adapted assay, based on the binding of porcine anti-guinea pig insulin antibodies to microtiter plates and insulin-peroxidase conjugate as displacer, is sensitive between 0.5 and 30 ng/ml. Since it uses only 10-40 microliter of sample material it enables the determination of 5-100 pg of insulin. The rapid (5-6 h), automatable, reproducible and reliable assay makes it possible to determine many samples in a short time.     

Sodium deoxycholate promotes the absorption of heparin administered orally, probably by acting on gastrointestinal mucosa, in rats

Sodium deoxycholate (DOC), selected as a promoter of gastrointestinal absorption of heparin, was administered orally to rats, followed, at increasing intervals, by heparin. Maximal plasma clearing activity (PC) was obtained with a 60-min interval, though PC was still elicited after 24 h, suggesting that DOC acts on the gastrointestinal mucosa. Inhibition of blood coagulation was also observed after oral heparin. The suggestion that DOC increases heparin absorption is supported by increased plasma levels of heparin. No signs of several gastrointestinal damage were seen.