Munological activity of transplanted spleens inXenopus laevis

Resumé Des rates immunisées deXenopus laevis qu'on greffe dans des hôtes qui les acceptent, peuvent y produire des réactions immunologiques. Ces réactions se dirigent ou contre l'hôte ou contre des gretfes épidermiques, prises à un troisième animal que l'hóte tolère. Au cours de ces réactions de greffe-coutre-hôte, la rate se trouve parfois attaquée.     

Changes in body temperature produced by injecting prostaglandin E1, EGTA and bacterial endotoxins into the PO/AH region and the medulla oblongata of the rat

Résumé La prostaglandine E₁ a causé de l'hyperthermie si on l'injectait dans la région préoptique/hypothalamique antérieure/des rats et de l'hypothermie au niveau de la région médullaire oblongue. L'EGTA, le Piromen et le vaccin typhoïdes ont rarement causé des changements parallèles dans la température rectale si on les injectait dans les deux régions cérébrales.

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This research was supported by PHS Research Grant No. 1-R01-NS-10046-01 from the National Institute of Neurological Diseases and Stroke. We thank Dr.J. Pike of Upjohn Laboratories for supplying the PGE₁.

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Medical student fellow in Psychiatry. Supported by the Hogg Foundation and PHS Grant No. 5 TO2 MH 5928 from the National Institute of Mental Health.     

Pleistocene Homo sapiens from Middle Awash,Ethiopia

The origin of anatomically modern Homo sapiens and the fate of Neanderthals have been fundamental questions in human evolutionary studies for over a century. A key barrier to the resolution of these questions has been the lack of substantial and accurately dated African hominid fossils from between 100,000 and 300,000 years ago. Here we describe fossilized hominid crania from Herto, Middle Awash, Ethiopia, that fill this gap and provide crucial evidence on the location, timing and contextual circumstances of the emergence of Homo sapiens. Radioisotopically dated to between 160,000 and 154,000 years ago, these new fossils predate classic Neanderthals and lack their derived features. The Herto hominids are morphologically and chronologically intermediate between archaic African fossils and later anatomically modern Late Pleistocene humans. They therefore represent the probable immediate ancestors of anatomically modern humans. Their anatomy and antiquity constitute strong evidence of modern-human emergence in Africa.