Warm tropical ocean surface and global anoxia during the mid-Cretaceous period

The middle of the Cretaceous period (about 120 to 80 Myr ago) was a time of unusually warm polar temperatures, repeated reef-drowning in the tropics and a series of oceanic anoxic events (OAEs) that promoted both the widespread deposition of organic-carbon-rich marine sediments and high biological turnover. The cause of the warm temperatures is unproven but widely attributed to high levels of atmospheric greenhouse gases such as carbon dioxide. In contrast, there is no consensus on the climatic causes and effects of the OAEs, with both high biological productivity and ocean 'stagnation' being invoked as the cause of ocean anoxia. Here we show, using stable isotope records from multiple species of well-preserved foraminifera, that the thermal structure of surface waters in the western tropical Atlantic Ocean underwent pronounced variability about 100 Myr ago, with maximum sea surface temperatures 3-5 degrees C warmer than today. This variability culminated in a collapse of upper-ocean stratification during OAE-1d (the 'Breistroffer' event), a globally significant period of organic-carbon burial that we show to have fundamental, stratigraphically valuable, geochemical similarities to the main OAEs of the Mesozoic era. Our records are consistent with greenhouse forcing being responsible for the warm temperatures, but are inconsistent both with explanations for OAEs based on ocean stagnation, and with the traditional view (reviewed in ref. 12) that past warm periods were more stable than today's climate.     

Circadian variation of serum testosterone in the adult male rat with a late morning acrophase

Summary Serum testosterone concentrations were measured in adult male Sprague-Dawley rats. A significant circadian testosterone rhythm (p<0.01) was found with peak values at 10.00 and 13.00 h.Supported in part by NIH, NCI Grant No. CA 15062 and NIH, NIAMDD Grant No. 5 RO1 AM11376.The authors would like to acknowledge the excellent technical assistance of Ms.Kris Strom.     

Urogastrone-epidermal growth factor is trophic to the intestinal epithelium of parenterally fed rats

Summary The weight of the stomach, small intestine and colon and the mucosal crypt cell production rate of these tissues were significantly decreased after 10 days on an isocaloric TPN diet when compared to orally fed controls. Continuous infusion of recombinant beta urogastrone, at a dose below that needed to inhibit gastric acid secretion, largely prevented this decrease in crypt cell production rate and gastrointestinal tissue weights.     

Phenolic content of sugarcane in relation to red rot disease

Zusammenfassung Hohe Konzentrationen an phenolischen Substanzen in Zuckerrohrpflanzen hemmen die durch den ParasitenCollectotrichum falcatum Went verursachte Pilzfäule.     

Access of reabsorbed glucose to renal lymph

Summary Measurements of the glucose to mannitol tracer concentration ratios in renal venous blood and renal lymph of rats supported the hypothesis that reabsorbed glucose may have direct access to renal lymph by passage through the interstitium.Acknowledgment. This research was supported by grant No. AM-17093 of the USPHS.