No abstract

Several central depressant and other drugs have been examined for their effects upon acetylcholine release from the stimulated, perfused cat superior cervical ganglion and rat isolated phrenic nerve-diaphragm preparations. The acetylcholine released was assayed biologically. Amylobarbitone sodium, chloral hydrate, trichloroethanol, methylpentynol, methylpentynol carbamate, paraldehyde, procaine hydrochloride and troxidone reduced the presynaptic release of acetylcholine from the ganglion. They also exhibited a postsynaptic blocking action, this component of depressant activity being particularly prominent with paraldehyde and troxidone. Closely analogous findings were obtained at the neuromuscular junction with methylpentynol and its carbamate, paraldehyde, procaine hydrochloride, trichloroethanol and troxidone. At both sites the drug-induced depression, both of transmission and of acetylcholine output, was reversible. Whereas hexamethonium regularly blocked ganglionic transmission with no effect upon acetylcholine release, tetraethylammonium not only completely blocked ganglionic transmission but concomitantly augmented acetylcholine output. These results are discussed in relation to the electrophysiological and metabolic events associated with neuro-effector transmission.

IN 1878 Ewald & Kiuhne measured the time necessary for.solutions of visual purple to become decolourized completely when heated to various temperatures. They also investigated the effects of NaCl and of the absence of water on the thermal bleaching, and concluded that the reactions were very similar to the coagulation of albumen by heat. Since very little is known about the chemical nature of visual purple, it was decided to extend these observations by making some quantitative measurements of its thermal bleaching at various hydrogen-ion concentrations. Apart from the theoretical interest, it is of practical importance to know the amount of decomposition which may be expected during certain operations on the substance.The experiments were carried out over the whole range of acidities within which visual purple is not very rapidly destroyed at room temperatures. The velocity of decomposition was followed by the progressive loss of optical density with time, and in what follows the term " decomposition of visual purple" means the loss of the typical colour since our only sure guide to the presence of visual purple is its characteristic wavelength absorption curve.

In this study neoadjuvant treatment with endocrine or chemotherapy provided no obvious survival benefit to women with breast cancer. However, it does allow avoidance of surgery in some cases. Also, the patients whose tumours respond to neoadjuvant systemic therapy have a lower incidence of distant metastases after five year follow-up compared to those whose tumours fail to respond.