The present study examines the possibility that lesions induced by intrastriatal injections of endothelin-1 (ET-1, 0.43 nmol/0.5 microliter) are ischemic in nature due to a vasoconstriction of the cerebral microvessels. In time course and dose-response experiments with ET-1 and in comparisons with ET-3, the volume of the lesions has been determined based mainly on the disappearance of striatal nerve cells, using a computer assisted morphometrical analysis. The blood flow in the neostriatum close to the site of injection of ET-1 was determined acutely by Laser-Doppler flowmetry. The acute metabolic effects of ET-1 were also studied on striatal superfusate levels of lactate, pyruvate, dopamine and its metabolites DOPAC (3,4-dihydroxyphenylacetic acid) and homovanillic acid (HVA) using an intrastriatal microdialysis probe. Dose related striatal lesions were observed with ET-1 (0.043-0.43 nmol) with a peak lesion volume after 24-48 h and the possible existence of a penumbra area. ET-3 showed a reduced potency to produce striatal lesions compared to ET-1. The lesions induced by ET-1 were prevented by coinjection with dihydralazine, a vasodilator drug. Acutely ET-1 (0.43 nmol/0.5 microliter) produced a prolonged reduction of the cerebral blood flow down to 40% of control values and temporary increases of striatal lactate and DA efflux, the latter change being very marked. Also a significant reduction of DOPAC and HVA was observed. These neurochemical changes were all prevented by treatment with dihydralazine.(ABSTRACT TRUNCATED AT 250 WORDS)

Different factors limit or enable reclassification, affecting consumer access to medicines in different countries. For countries attempting to reduce barriers to reclassification, solutions may include garnering government support for reclassification, support and flexibility from the medicines regulator, having a pharmacy-only and/or pharmacist-only category, providing market exclusivity, ensuring best practice in pharmacy, and minimizing the cost and delays of reclassification.

BackgroundSwitching or reclassifying medicines with established safety profiles from prescription to non-prescription aims to increase timely consumer access to medicines, reduce under-treatment and enhance self-management. However, risks include suboptimal therapy and adverse effects. With a long-standing government policy supporting switching or reclassifying medicines from prescription to non-prescription, the United Kingdom is believed to lead the world in switch, but evidence for this is inconclusive. Interest in switching medicines for certain long-term conditions has arisen in the United Kingdom, United States, and Europe, but such switches have been contentious. The objective of this study was then to provide a comprehensive comparison of progress in switch for medicines across six developed countries: the United States; the United Kingdom; Australia; Japan; the Netherlands; and New Zealand.MethodsA list of prescription-to-non-prescription medicine switches was systematically compiled. Three measures were used to compare switch activity across the countries: “progressive” switches from 2003 to 2013 (indicating incremental consumer benefit over current non-prescription medicines); “first-in-world” switches from 2003 to 2013; and switch date comparisons for selected medicines.ResultsNew Zealand was the most active in progressive switches from 2003 to 2013, with the United Kingdom and Japan not far behind. The United States, Australia and the Netherlands showed the least activity in this period. Few medicines for long-term conditions were switched, even in the United Kingdom and New Zealand where first-in-world switches were most likely. Switch of certain medicines took considerably longer in some countries than others. For example, a consumer in the United Kingdom could self-medicate with a non-sedating antihistamine 19 years earlier than a consumer in the United States.ConclusionProactivity in medicines switching, most notably in New Zealand and the United Kingdom, questions missed opportunities to enhance consumers' self-management in countries such as the United States.

No abstract

No abstract