Persistence Of Action Research Articles

Some studies on the systemic activity of the thiophanate fungicides in plants

AbstractThree closely related fungicides, thiophanate (NF 35), thiophanate methyl (NF 44) and NF 48 have been found to be active against a wide range of diseases including the powdery mildews of apple, cucumber and barley; apple and pear scab and grey mould of soft fruit. This paper deals with the preliminary experiments to compare their relative mobilities and biological persistence in crop plants, using the powdery mildews as indicator infections.NF 44 and NF 48 in particular showed a high degree of systemic activity by root uptake and persistence of action against barley and cucumber mildew but very little systemic activity against apple mildew on potted rootstocks. They have also displayed trans‐laminar and localised movement towards the leaf apex in sprayed cucumber and barley leaves but movement was not so marked in sprayed apple leaves.NF 48 was also active as a seed dressing against loose smut of barley.

Intramuscular administration of digoxin in propylene glycol.

SummaryDigoxin in 40% propylene glycol and 10% ethanol was injected intramuscularly in 7 patients with auricular fibrillation. Its full cardiac effect was reached in 8 hours, while intravenous digoxin in the same patients reached full effect in 2 hours. Intensity and persistence of action were the same for both routes. Additional intramuscular injections in 26 patients revealed pain but no permanent tissue damage.

Clinical studies of gitalin and of digitalis in the treatment of auricular fibrillation

A comparative study of the actions of gitalin and digitalis was made in thirty-six ambulant patients with auricular fibrillation. Gitalin acts like digitalis in slowing the ventricular rate and relieving congestive heart failure in patients with auricular fibrillation. Gitalin parallels digitalis in its effect on the R-T transition and T-waves of the electrocardiogram. Gitalin has a persistence of action at least as long as digitalis. Rapid administration of gitalin in eight patients produced prompt and effective slowing of ventricular rates and clinical improvement without the development of toxic symptoms. The average daily maintenance dose of gitalin was 1 110 grain; of digitalis, 2 1 4 grains, or 1 1 2 cat units. Clinically, 1 160 grain of gitalin is equivalent to 1 cat unit of digitalis leaves. The daily maintenance dosages of both drugs show considerable variations in different individuals. Toxic reactions to gitalin are the same as to digitalis. They are neither more nor less frequent. With careful administration they should be rare with either drug. Our studies indicate that digitalis can slow ventricular rates in auricular fibrillation in the absence of heart failure, which is contrary to the contention that slowing of the ventricular rate in auricular fibrillation is effected by digitalis only in the presence of heart failure.

A comparative study of ephedrine, tyramine and epinephrine with special reference to the circulation: Chen, K. K., and Meek, Walter J.: Jour. Pharmacol. and Exper. Therap., 1926, xxviii, 59

1. The blood pressure raising property of ephedrine is not conveniently compared with epinephrine equimolecularly. Suitable doses of ephedrine, however, can make the pressure rise to almost the same level as ordinary doses of epinephrine given to laboratory animals, and maintain it for a much longer time. When mixed with epinephrine, ephedrine shows synergism not only in intensity but in duration. 2. Tyramine, compared with ephedrine, molecule for molecule, raises blood pressure higher but does not maintain a high level as long, when injected intravenously in anesthetized dogs. On repeated injections in stimulating doses, tyramine, when given at intervals of fifteen to twenty minutes does not rapidly lose its effectiveness in raising the blood pressure as ephedrine does. Like ephedrine, tyramine shows synergism with epinephrine both in intensity and duration. In men when given by mouth, tyramine fails to raise blood pressure while ephedrine does. 3. Tyramine, when injected intravenously in anesthetized dogs, increases the heart rate and amplitude of contractions, if the vagi are atropinized, during the rise of blood pressure. Under the same conditions, it increases the cardiac minute output as confirmed by cardiometric and teleroentgenographic studies. Large doses of tyramine also produce a sudden fall of blood pressure, but this fall, unlike ephedrine, is not due to the interference of the automatic and conductive system of the heart as shown by the electrocardiogram, but due to vasodilatation. 4. An explanation based on chemical structure for the difference of chemical stability and persistence of action between tyramine and epinephrine on the one hand and ephedrine on the other, has been offered.