The reaction of alkylating agents with bacteriophage R17. Biological effects of phosphotriester formation

The extent of biological inactivation and of the degradation of the RNA after reaction of bacteriophage R17 with ethyl methanesulphonate, isopropyl methanesulphonate and N-ethyl-N-nitrosourea was studied. Formation of breaks in the RNA chain probably results from hydrolysis of phosphotriesters formed in the alkylation reactions. Near neutral pH the ethyl and isopropyl phosphotriesters are sufficiently stable for the kinetics of the hydrolysis reaction to be followed. Results indicate that the rate of hydrolysis increases rapidly as the pH is raised. The evidence shows that a phosphotriester group does not itself constitute a lethal lesion. The extent of phosphotriester formation by the different agents is discussed in terms of reaction mechanism.     

The metabolism of d-glyceraldehyde by the lens

1. The metabolism of d-glyceraldehyde by the lens was examined. 2. When low concentrations of d-[U-(14)C]glyceraldehyde were incubated with lens extracts there was no incorporation of the label into protein; more than two-thirds of the labelled metabolites consisted of glyceric acid and glycerol, their relative proportions depending on the species. Lactic acid, a phosphate, glutathione-glyceraldehyde compounds and a neutral compound were also formed. 3. When high concentrations of d-[U-(14)C]glyceraldehyde were incubated with lens, extensive incorporation of the label into protein occurred and the protein became yellow-brown. This coloured protein did not exhibit the fluorescent properties shown by the brown proteins of human cataractous senile lens, or of naphthaquinone-treated lens. 4. Evidence that d-glyceraldehyde is formed by the lens was sought but not found.     

Hyperthyroidism with Periodic Paralysis

Hyperthyroidism may be associated with hypokalemic periodic paralysis. Two cases are presented demonstrating intermittent attacks of flaccid paralysis associated with clinical symptoms, signs and laboratory findings of hyperthyroidism. During an attack, one patient had a serum potassium of 2.1 mEq. per litre.Various factors such as trauma, exposure to cold, excessive carbohydrate ingestion and certain medications have been stated to precipitate an episode of paralysis. Attacks may range from mild weakness to generalized flaccid paralysis with loss of deep tendon reflexes. Several reported patients have died owing to cardiac arrest or respiratory paralysis.During attacks, the serum potassium is usually in the range of 2.2 to 3.2 mEq. per litre. It is postulated that a metabolic abnormality affecting the muscle-cell membrane can occur in the hyperthyroid state resulting in a shift of potassium to the intracellular position, thus producing a situation of hyperpolarization of the muscle-cell membrane which in turn alters the muscle contractibility.The importance of recognizing the unusual association of hypokalemic periodic paralysis with hyperthyroidism is stressed because, with successful treatment of the hyperthyroidism, the episodes of paralysis disappear.     

Dämpfung der Gewebeatmung (QO2) von Mäuseleber durch künstliche Impulsstrahlung

Zusammenfassung In einem gegen die natürliche Langwellenstrahlung abgeschirmten Versuchsraum wurde die Atmung von Mäuselebergewebe in künstlich erzeugten elektromagnetischen Feldern gemessen. Unter der Einwirkung von zyklonale Wetterlagen simulierenden Programmen (30–100 pulses sec^–1, > 100 mV m^–1, 10–100 kHz) ergab sich im Vergleich zu den Kontroll-QO₂-Werten eine signifikante Dämpfung der Gewebeatmung um 42% ± 2,8% (p<0,001). Die Applikation eines H-Feld-Programms blieb ohne Wirkung. Programme mit Simulierung antizyklonaler Wetterlagen(1–3 pulses sec^–1, <10 mV m^–1, 10 kHz) hatten ebenfalls keinen Einfluss auf die Atmungsgeschwindigkeit der Mäuseleber.

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In a room completely shielded against long wave radiation, liver tissue of mice in a Warburg apparatus was exposed to artificial electromagnetic radiation simulating cyclonic and anticyclonic weather. Under the influence of simulated cyclonic weather programs (30–100 pulses sec^–1, > 100 mV m^–1 10–100 kHz) a significant decrease (42% ± 2,8%) of the respiration rate of the liver tissue was found, compared with the control QO₂ (p < 0,001). The application of a cyclonic weather H-field program had no effect. Simulated anticyclonic weather (1–3 pulses sec^–1, < 10 mV m^–1, 10 kHz) also failed to produce a demonstrable effect on the respiration rate of mouse liver tissue.

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Resume Dans un local absolument protégé contre l'irradiation naturelle par ondes longues, des tissus de foie de souris ont été exposés, dans un appareil de Warburg, à des impulsions électromagnétiques artificielles, correspondant à celles de temps cyclonal et anticyclonal. Sous l'influence des programmes artificiels simulant le temps cyclonal(30–100 pulses sec^–1, > 100 mV m^–1, 10–100 kHz), il a été constaté une inhibitation significative de la respiration tissulaire de 42% ± 2,8% comparée aux valeurs du QO₂ de contrôle (p < 0.001). L'application d'un temps cyclonal-"H-field"-programme séparé, est demeuré sans effet. De même. les signaux de temps anticyclonal(1–3 pulses sec^–1, < 10 mV m^–1, 10 kHz), n'ont eu aucune influence démonstrable sur la vitesse de respiration du fois de souris.