A tissue-selective prostaglandin E2 analog with potent antifertility effects.

N-methanesulfonyl 16-phenoxy-omega-tetranor PGE2 is a prostaglandin analog which is markedly more tissue selective than PGE2. This compound is 10-30 times more potent than PGE2 in animal models which are considered relevant to antifertility effects in humans. In pharmacological tests which are believed to be predictive for side effects in humans, the compound has potency either equal to or less than that of PGE2.     

Die Abhängigkeit der Ca++-Aufnahme isolierter Mitochondrien des Herzmuskels von der Na+-und K+-Konzentration als mögliche Ursache der inotropen Digitaliswirkung

Summary In isolated mitochondria of heart muscle from rabbits and oxen there is, under suitable conditions, an accumulation of Ca⁺⁺, which is significantly enhanced by elevating the K⁺/Na⁺ quotient of the incubation medium. K-strophanthine (10^–5–10^–7) does not influence the accumulation of Ca⁺⁺ by the mitochondria of heart muscle. Therefore the intracellular increase in exchangeable Ca⁺⁺ observed after digitalis-glycosides could be explained by a decrease of the intracellular K⁺/Na⁺ quotient, which is caused by inhibition of the membrane ATPase and diminishes the capacity for Ca⁺⁺ accumulation in mitochondria.     

Ultrastructure of Eocene fossil plants

Petrified leaf and pericarpic tissues from the Eocene Deccan Intertrappean beds of India were studied using light and transmission electron microscopy. Degradated cytoplasm with organellelike bodies are present in cells of the leaf tissues. TEM of these cells revealed wall structure and cytoplasmic residues. Microfibril distribution of pericarpic cells resembles fiber cells in extant angiosperms.     

Export by red blood cells of nitric oxide bioactivity

Previous studies support a model in which the physiological O2 gradient is transduced by haemoglobin into the coordinate release from red blood cells of O2 and nitric oxide (NO)-derived vasoactivity to optimize oxygen delivery in the arterial periphery. But whereas both O2 and NO diffuse into red blood cells, only O2 can diffuse out. Thus, for the dilation of blood vessels by red blood cells, there must be a mechanism to export NO-related vasoactivity, and current models of NO-mediated intercellular communication should be revised. Here we show that in human erythrocytes haemoglobin-derived S-nitrosothiol (SNO), generated from imported NO, is associated predominantly with the red blood cell membrane, and principally with cysteine residues in the haemoglobin-binding cytoplasmic domain of the anion exchanger AE1. Interaction with AE1 promotes the deoxygenated structure in SNO-haemoglobin, which subserves NO group transfer to the membrane. Furthermore, we show that vasodilatory activity is released from this membrane precinct by deoxygenation. Thus, the oxygen-regulated cellular mechanism that couples the synthesis and export of haemoglobin-derived NO bioactivity operates, at least in part, through formation of AE1-SNO at the membrane-cytosol interface.     

Imaging of localized electronic states in the quantum Hall regime

The concept of electron localization has long been accepted to be essential to the physics of the quantum Hall effect in a two-dimensional electron gas. The exact quantization of the Hall resistance and the zero of the diagonal resistance over a range of filling factors close to integral are attributed to the localization of electronic states at the Fermi level in the interior of the gas. As the electron density is changed, charging of the individual localized states may occur by single-electron jumps, causing associated oscillations in the local electrostatic potential. Here we search for such a manifestation of localized states in the quantum Hall regime, using a scanning electrometer probe. We observe localized potential signals, at numerous locations, that oscillate with changing electron density. In general, the corresponding spatial patterns are complex, but well-defined objects are often seen which evidently arise from individual localized states. These objects interact, and at times form a lattice-like arrangement.     

Modelle für Reaktionen zwischen organischen und mineralischen Substanzen im Boden

Summary Low molecular siloxanes, silicagel, aluminium oxide, permutite, and perlite were dissolved by ammoniacal catechol solution. Silicagel was also dissolved by othero-diphenols. Low molecular silicon organic ester or complex compounds were crystallised from the reaction products of silicagel with catechol and 2,3-naphthalenediol. On orthoclase an insoluble brown cover was formed. The reaction ofo-diphenols with silicates may be important in soil formation.     

Substantivity and other factors responsible for formazan patterns in dehydrogenase histochemistry

Zusammenfassung Es wurden substantive Eigenschaften verschiedener Mono- und Ditetrazoliumsalze gegenüber Gewebebestandteilen im Schnittpräparat untersucht. Ditetrazole werden im allgemeinen stärker vom Gewebe adsorbiert als Monotetrazole. Ausnahmen bilden Monotetrazole mit polaren Substituenten oder Azobenzol-Resten in 3-Stellung. Ditetrazole mit elektronegativen Gruppen in 2-Stellung werden stark von Lipoprotein-Strukturen adsorbiert und zeigen in Modellexperimenten Substantivität für ungesättigte Lipoide. An verschiedenen Beispielen wird die Bedeutung substantiver Tetrazol-Eigenschaften für die Lokalisation von Dehydrogenaseaktivität im Schnittpräparat dargelegt. Die Lokalisation enzymatisch gebildeten Formazans ist im Falle von substantivem Tetrazol ein Ausdruck für die Adsorption der Farbstoffvorstufe an bestimmte Gewebekomponenten. Im Falle von nichtsubstantivem Monotetrazol besteht die Möglichkeit zur Bestimmung von Orten intrazellulärer Enzymaktivität ohne unspezifische Anfärbung von Gewebsbestandteilen. Die Bedeutung der stark voneinander abweichenden Eigenschaften von in der Histochemie gebräuchlichen Tetrazoliumsalzen für die Darstellung intra-und extramitochondrialer Aktivität wird diskutiert.

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Acknowledgments. We are indebted to ProfessorH. Beyer for the gift of MTT, to Dr.A. M. Seligman for Nitro-BT, to Dr.A. W. Nineham for M and B 1762 A and 1767 and to Dr.G. Glenner for BCT. We are grateful to Dr.G. Popják for assistance in the preparation of cell fractions. One of us (A. G. E. P.) is in receipt of a Grant in Aid from the Medical Research Council.     

Comparative dominant lethal studies with phenylbutazone,thio-TEPA and MMS in the mouse

Zusammenfassung Im Gegensatz zu Thio-TEPA (N, N, N-Triaethylen-thiophosphoramid) und MMS (Methansulfonsäuremethylester) führten i.p. Dosen von Phenylbutazon (50 und 100 mg/kg) bei der Maus, unter Berücksichtigung von post- und prae-implantativen Gestationsstadien, zu keinen genetischen Effekten im Sinne der Induktion von dominanten Letalfaktoren.