Influence of pinealectomy on corticotropin (ACTH)

Summary Sensory deprivation produced by removing the eyes and olfactory bulbs in male rats allowed pinealectomy to markedly augment the post-adrenalectomy elevation of ACTH levels. Pineal removal or sensory deprivation separately did not have this effect. Thus, intact sensory input and an intact pineal gland are independently capable of restricting the post-adrenalectomy rise in ACTH levels.This work was supported in part by NIH Grant No. P30 HD 10202. We thank F. Lynd and R.J. Reiter for advice, P. Starr and J. Sackman for technical assistance, and Bess Mitchell for typing.     

The HIV tat gene induces dermal lesions resembling Kaposi's sarcoma in transgenic mice

When the human immunodeficiency virus transactivating gene under the control of the viral regulatory region is introduced into the germline of mice, skin lesions are induced that resemble Kaposi's sarcoma seen in AIDS. Our findings indicate that HIV could play a direct part in causing cancer.     

Colour mixing and colour preferences in neonate gulls

Zusammenfassung Junggeschlüpfte Silber- und Heringsmöven zeigen beim Picken von kleinflächigen, beweglichen Reizen Spektralfarbbevorzugungen. Drei theoretische Modelle sind vorgeschlagen worden, die diese Bevorzugungen erklären sollen. Die Voraussagen dieser Modelle bezüglich der Bevorzugung von Mischfarben wurden experimentell geprüft und als nicht zutreffend befunden. Vielmehr legen die Ergebnisse die Vermutung nahe, dass die Bevorzugung nicht, wie bisher angenommen, auf einem afferenten sensorischen Filtermechanismus beruht, sondern auf einen mehr zentralen, postperzeptualen Prozess zurückzuführen ist.     

Superoxide dismutase activity during the plasmodial life cycle ofPhysarum polycephalum

Summary Superoxide dismutase activity was slow throughout the cell cycle of surface cultures ofPhysarum polycephalum. This activity increased markedly when the organism was induced to spherulate. Glutathione (GSH) and hydrogen peroxide (H₂O₂) concentrations changed very little during the cell cycle. During spherulation GSH decreased; H₂O₂ and the cyanide-resistant respiration of plasmodial homogenates increased.     

Cholinergic-rich brain transplants reverse alcohol-induced memory deficits

Alcohol-induced memory impairment in man has been attributed to deficiencies in subcortical noradrenergic and cholinergic systems, as well as to damage in midbrain structures. Korsakoff's psychosis, a disease in which alcohol poisoning causes apparently irreversible memory defects, is characterized by lesions in cholinergic and noradrenergic nuclei and by a decrease in the activity of choline acetyltransferase (ChAT) and the content of noradrenaline (NA) in forebrain areas such as cerebral cortex and hippocampus, innervated by these nuclei. Prolonged intake of ethanol in rodents similarly produces signs of noradrenergic and cholinergic deafferentation in the cortex and hippocampus, as well as persistent memory deficits. To test whether alcohol-induced memory impairments depend on cholinergic deafferentation, we transplanted cholinergic-rich fetal basal forebrain cell suspensions into the cortex and hippocampus of alcohol-treated rats. The substantial and persistent memory losses produced in our rats by ethanol intake were associated with an impairment of cholinergic function, and were reversed by cholinergic-rich transplants into cortex and hippocampus.     

New Amphenone analogs as adrenocortical inhibitors

Zusammenfassung 2-Methyl-1,2-bis-(3-pyridyl)-1-propanon (Su 4885) hemmt beim Hund die Ausscheidung von 17-OH-Steroiden aus den Nebennieren und hemmtin vitro ähnlich wie Amphenon den ACTH-Effekt auf Ratten-, Meerschweinchen-und Hunde-Nebennieren.In situ bei der Ratte hat es jedoch keine Amphenon-Wirkung, von dem es sich auch sonst unterscheidet.     

Brevetoxicosis: red tides and marine mammal mortalities

Potent marine neurotoxins known as brevetoxins are produced by the 'red tide' dinoflagellate Karenia brevis. They kill large numbers of fish and cause illness in humans who ingest toxic filter-feeding shellfish or inhale toxic aerosols. The toxins are also suspected of having been involved in events in which many manatees and dolphins died, but this has usually not been verified owing to limited confirmation of toxin exposure, unexplained intoxication mechanisms and complicating pathologies. Here we show that fish and seagrass can accumulate high concentrations of brevetoxins and that these have acted as toxin vectors during recent deaths of dolphins and manatees, respectively. Our results challenge claims that the deleterious effects of a brevetoxin on fish (ichthyotoxicity) preclude its accumulation in live fish, and they reveal a new vector mechanism for brevetoxin spread through food webs that poses a threat to upper trophic levels.