31P-NMR study on nucleotides and intracellular pH of hereditary spherocytes

Summary As determined by³¹p-NMR spectroscopy, intracellarar pH of hereditary spherocytes was lower (pH 6.7–6.9) than that of normal red cells. The level of adenosine diphosphate in hereditary spherocytes was found to be persistently high. The metabolism of nucleotides and other phosphoryl compounds in human red blood cells have been studied in detail by³¹p-NMR spectroscopy^1–3. However, to our knowledge, there seems to be no report describing the result of³¹p-NMR spectroscopy on red blood cells from hereditary spherocytosis.     

Deformation of transforming red cells in various pH solutions

Summary Centrifugation into a rapid cell fixative is used to determine the conformation of red cells at various pH-values as a measure of red cell deformability. Discocytes show a good deformation into handbag-like forms; echinocytes and stomatocytes have reduced deformability with characteristic shapes of deformation.     

31P-NMR study on nucleotides and intracellular pH of hereditary spherocytes.

As determined by 31p-NMR spectroscopy, intracellular pH of hereditary spherocytes was lower (pH 6.7-6.9) than that of normal red cells. The level of adenosine diphosphate in hereditary spherocytes was found to be persistently high. The metabolism of nucleotides and other phosphoryl compounds in human red blood cells have been studied in detail by 31p-MNR spectroscopy. However, to our knowledge, there seems to be no report describing the result of 31p-NMR spectroscopy on red blood cells from hereditary spherocytosis.     

Use of indomethacin to reverse neonatal hypotension

Summary Treatment with indomethacin elevated systemic arterial pressure and pulmonary vascular resistance in hypotensive newborn goats. Indomethacin may be of value in restoration of systemic arterial pressure in stress-induced hypotension.Supported in part by Nos. NIH-HL-10834-06, NIH-T01-HL05979-02S1 and Florida Heart No. 74-AG-2.Acknowledgments. The authors wish to thankN. L. Murtha, L. Tumarkin, J. Howard andP. Eitzman for their technical assistance and Merck, Sharpe and Dohme for the gift of indomethacin. This research was conducted under the guiding principles in the care and use of animals approved by the Council of the American Physiological Society and the National Institute of Health.     

A measure of time series' predictability using genetic programming applied to stock returns

Based on the standard genetic programming (GP) paradigm, we introduce a new probability measure of time series' predictability. It is computed as a ratio of two fitness values (SSE) from GP runs. One value belongs to a subject series, while the other belongs to the same series after it is randomly shuffled. Theoretically, the boundaries of the measure are between zero and 100, where zero characterizes stochastic processes while 100 typifies predictable ones. To evaluate its performance, we first apply it to experimental data. It is then applied to eight Dow Jones stock returns. This measure may reduce model search space and produce more reliable forecast models. Copyright © 1999 John Wiley & Sons, Ltd.     

Acceleration of red cell glycolysis by citrate due to intracellular pH enhancement

Zusammenfassung Nachweis, dass in Konsequenz der intra- und extrazellulären pH-Differenz, das Citrat die Erythrocyten Glycolyse beschleunigt.     

Standardization of "exchange" techniques to measure estradiol receptors in extracts exposed to biospecific adsorbants]

The measurement of the binding of steroid hormone receptors to biospecific adsorbants requires the development of "exchange" techniques. Two types of techniques based on the principle of differential dissociation were standardized: solid phase exchange with hydroxylapatite and liquid phase exchange with adsorption of the ligand to charcoal dextran. In both cases, binding of oestradiol to its receptor was measured in calf uterine cytosol extracts. Results obtained by both techniques were comparable. The half-times of the oestradiol-receptor complex dissociation determined from exchange kinetics are on the same order as those obtained by direct methods used in previous studies.     

The use of nuclear emulsions to determine small amounts of P33 present in samples of P32

Zusammenfassung Es wird eine Methode beschrieben, welche die Bestimmung kleiner Mengen P³³ in altem Radiophosphor erlaubt: P³³-Beta-Spuren werden ausgezählt in 200 dicken Emulsionsschichten, in denen sie in ihrer ganzen Reichweite enthalten sind.     

Fluorescence response of acridine orange to changes in pH gradients across liposome membranes

The influence that changes in proton distribution have on the fluorescence of acridine orange was examined using negatively charged liposomes. Our results indicate that at least two mechanisms are involved: distribution of the probe between the internal aqueous phase of the liposomes and the outside medium, and binding of the probe to the liposome membranes.     

Fluorescence response of acridine orange to changes in pH gradients across liposome membranes

Summary The influence that changes in proton distribution have on the fluorescence of acridine orange was examined using negatively charged liposomes. Our results indicate that at least two mechanisms are involved: distribution of the probe between the internal aqueous phase of the liposomes and the outside medium, and binding of the probe to the liposome membranes.     

Sensitivity of crayfish muscle fibers to glutamate and to natural transmitter in low calcium solutions]

The response of crayfish muscle fibres to glutamate, a putative transmitter at its excitatory motor synapses, decreases when extracellular calcium is reduced, whereas the sensitivity to natural transmitter s not modified. Three possible mechanisms are proposed.     

An experimental approach to pH measurement in the intercellular free space of higher plant tissues

Summary An experimental approach to the measurement of pH in the free space of plant tissues was made, using both metal minielectrodes and H⁺-sensitive resin glass microelectrodes inserted in small environments artificially created inside the tissue. Experiments were carried out on the parenchyma of higher plants (corn, potato, squash,Senecio herraianus), monitoring pH changes in the free space as a function of the pH of the external medium. The pH in the free space has been found to be different from that of the surrounding solution and its variation in time much slower than would be predicted by assuming that simple diffusion of H⁺ ions took place. The results agree with the hypothesis that the free space behaves as a compartment distinct from both the cytosol and the surrounding medium.