Having been the Foreign Secretary of the Academy of Sciences of Cuba and Executive Director of the institution for many years, he was elected Member of Honor of both, the Academies of Sciences of Cuba, Guatemala and the Caribbean. He was President of the Caribbean Scientific Union from 2005 to 2007. A historian and philologist graduated at the University of Havana, he took further studies at the Institute of International Relations of Cuba.

From 2003 to 2018, Pastrana was the Cuban representative to the Executive Committee of IAP, the Global Network of Academies of Sciences, where he chaired the Membership Committee. He was a member of the Executive Board of the International Council for Science (ICSU) (2005-2014) and Vice President (2012-2014). He has widely represented Cuban and Caribbean scientists at international meetings on science. A consultant to various UN agencies, he has been appointed special envoy of the Republic of Cuba for the signing of intergovernmental agreements, and has been official representative of Cuba, on behalf of Cuban scientists on many occasions. He has published numerous articles and book chapters in Cuba and abroad on the subject of the history of international relations of science, as well as on the advisory role of Academies of Sciences.