Ein Portr?t von Prof. Dr. Dr. h. c. Wolfgang Engel

Personalia

Ein Portr?t von Prof. Dr. Dr. h. c. Wolfgang Engel     

DSMB. 1. What role, what responsibilities?

In addition to the IRB (Institutional review board), the DSMB (data safety and monitoring board) takes an increasing role in the monitoring of clinical trials, especially in large multicenter trials. The DSMB is a an expert committee, independent from the investigators and the sponsor of the trial, which periodically examines the safety data accumulated during progress of the trial and ensures that the benefit/risk ratio remains acceptable for participating patients. The DSMB is also a safeguard for the scientific integrity of the trial. It is the only committee which can have access to unblinded data from the trial. The DSMB may recommend termination of the trial in three situations : (1) occurrence of unanticipated adverse events which may pose a serious risk for participating patients; (2) demonstration of efficacy before the planned accrual \; (3) and because of "futility" (the most difficult situation), i.e. in absence of a reasonable probability that the trial may reach a conclusion within its planned frame.     

Crop biotechnology. Where now?

Nature Biotechnology organized a conference in London on Agobiotech 99: Biotechnology and World Agriculture (November 14-16, 1999). The conference focused entirely on crop biotechnology and covered both societal and scientific aspects. Below is an account of the more important issues raised by the speakers and the audience.     

Ecole d'été de l'A.C.E.M.I.—Ha?ti

Six Canadian medical students record their experience at a summer school of tropical medicine in Haiti, sponsored by the Canadian Association of Medical Students and Internes. The social, economic and medical background is described, including “Voodoo” practices, language and Haitian art. Attention is directed to the occurrence of umbilical tetanus, diarrhea and malnutrition. From even a brief stay in a country such as Haiti one comes to appreciate that a public health program in an underdeveloped nation is not strictly a medical undertaking but must be seen in its social and economic contexts.     

Pavlov vs. K?hler. Pavlov's little-known primate research

During the 1920s, I. P. Pavlov's scholarly interests broadened to consider problem-solving. Distrusting Wolfgang K?hler's Gestalt explanation of the problem-solving process and its interspecies aspects, Pavlov performed, from 1933 to 1936, a number of experiments, including a replication of K?hler's building experiment, using chimpanzees as subjects. Confirming K?hler's findings, Pavlov explained the problem-solving process in terms of unconditional reflexes and the establishment, by Pavlovian conditioning and the Thorndikian method of trial and error, of temporary neural connections identical, on the psychological level, to associations. In contrast to K?hler's "structural" explanation, Pavlov emphasized the processes of analysis and synthesis. According to Pavlov insight is achieved progressively--as the result of the organism's problem-solving behavior--contradicting K?hler's thesis of a sudden subjective reorganization of the environmental situation. Pavlov explained interspecies differences among higher organisms in terms of the range of a species behavior, with the second signal system as the main distinguishing characteristic between human and nonhuman species.     

?Kenyaichthyidae fam. nov. and ?Kenyaichthys gen. nov. – First Record of a Fossil Aplocheiloid Killifish (Teleostei,Cyprinodontiformes)

The extant Cyprinodontiformes (killifishes) with their two suborders Cyprinodontoidei and Aplocheiloidei represent a diverse and well-studied group of fishes. However, their fossil record is comparatively sparse and has so far yielded members of the Cyprinodontoidei only. Here we report on cyprinodontiform fossils from the upper Miocene Lukeino Formation in the Tugen Hills of the Central Rift Valley of Kenya, which represent the first fossil record of an aplocheiloid killifish. A total of 169 specimens - mostly extraordinarily well preserved - and a sample of ten extant cyprinodontiform species were studied on the basis of morphometrics, meristics and osteology. A phylogenetic analysis using PAUP was also conducted for the fossils. Both the osteological data and the phylogenetic analysis provide strong evidence for the assignment of the fossils to the Aplocheiloidei, and justify the definition of the new family †Kenyaichthyidae, the new genus †Kenyaichthys and the new species †K. kipkechi sp. nov. The phylogenetic analysis unexpectedly places †Kenyaichthys gen. nov. in a sister relationship to the Rivulidae (a purely Neotropical group), a probable explanation might be lack of available synapomorphies for the Rivulidae, Nothobranchiidae and Aplocheilidae. The specimens of †K. kipkechi sp. nov. show several polymorphic characters and large overlap in meristic traits, which justifies their interpretation as a species flock in statu nascendi. Patterns of variation in neural and haemal spine dimensions in the caudal vertebrae of †Kenyaichthys gen. nov. and the extant species studied indicate that some previously suggested synapomorphies of the Cyprinodontoidei and Aplocheiloidei need to be revised.