The effects of 11-methyl 16,16 dimethyl prostaglandin E2 on gastric acid secretion in man

11-Methyl 16,16 Dimethyl Prostaglandin E₂ (TM-PGE) was administered orally to man in dosages of 2.5, 5, 7.5 and 10 μg/kg. Maximal inhibition of basal secretion was 52 and 78% and submaximal histamine-stimulated secretion 45 and 70% for volume and acid output, respectively. Secretory inhibition was observed for approximately two hours after ingestion of the drug. No effect was observed on serum gastrin levels. Side effects occurred with equal frequency in the placebo and drug groups. TM-PGE is well tolerated and inhibits both basal and submaximal histamine-stimulated acid secretion in man. Further evaluation may prove it to be helpful in the clinical treatment of acid hypersecretory states and peptic ulcer disease.     

Details of glycosaminoglycan conformations and intermolecular interactions.

Among the mucopolysaccharides, similarities of chemical constitution are manifested in the similar molecular conformations that can be assumed by most of them. The differences, however, result in a preference for particular conformations. Small amounts of one glycosaminoglycan in a mixture can change the conformational preference of the major component. Advances in the techniques of fiber diffraction analysis allow us to visualize the roles of water and ions in some of these structures and to rationalize the strikingly different effects produced by Ca2+ and Na+ in hyaluronate systems, for example.     

Localization of Cu and heme a on cytochrome c oxidase polypeptides.

After mild dissociation of cytochrome $\text{c}$ oxidase protomers, and polyacrylamide gel electrophoresis, copper was found predominantly in polypeptides of Bands V (m.w. 12,100) and VII (m.w. 3,400), and heme a predominantly in polypeptides of Bands I (m.w. 35,300) and II (m.w. 21,000). Some copper was found in Band II – III, and heme a in Band V.     

Changes in Levels of Phosphoenolpyruvate Carboxylase with Induction of Crassulacean Acid Metabolism in Mesembryanthemum crystallinum L.

Expanded leaves of Mesembryanthemum crystallinum L. performingC₃ photosynthesis were induced to perform pronounced Crassulaceanacid metabolism (CAM) by exposing the plant roots to higherNaCl concentration. Levels of phosphoenolpyruvate (PEP) carboxylaseactivity increased 10-fold during the 7-day induction period.Densitometric analysis of Coomassie-stained sodium dodecyl sulfate(SDS) polyacrylamide gradient slab gels of leaf extracts, preparedduring the course of CAM induction, revealed that at least fivebands of polypeptides increased in content (kilodalton valuesof 98, 91, 45, 41, 38). Higher levels of three additional polypeptides(kilodalton values of 102, 76, 33) became apparent after tissuehad been grown for 2 weeks at 400 mM NaCl. Of these polypeptides,that having a mass of 98 kilodaltons was identified as the subunitof PEP carboxylase by comparison with the corresponding bandfrom partially purified PEP carboxylase from the same tissue.Only a faint 98 kilodalton band was evident on SDS gels fortissue operating in the C₃ mode; staining intensity at thislocation increased with increasing NaCl-salinity in the rootingmedium until CAM was fully induced. These data provide evidencefor net synthesis of PEP carboxylase and several other proteinsduring the induction of CAM in M. crystallinum. ¹ Present address: USDA, P. O. Box 867 Airport Rd., Beckley,WV. 25801, U.S.A. ² Present address: Department of Botany, Washington State University,Pullman, Washington 99164, U.S.A. ³ Present address: Botanisches Institut der Universit?t, MittlererDallenbergweg 64, 8700 W?rzburg, W.-Germany. (Received October 27, 1981; Accepted March 15, 1982)     

Activity and quantity of ribulose bisphosphate carboxylase-and phosphoenolpyruvate carboxylase-protein in two Crassulacean acid metabolism plants in relation to leaf age,nitrogen nutrition,and point in time during a day/night cycle

Activity of ribulose 1,5-bisphosphate (RuBP) carboxylase in leaf extracts of the constitutive Crassulacean acid metabolism (CAM) plant Kalanchoe pinnata (Lam.) Pers. decreased with increasing leaf age, whereas the activity of phosphoenolpyruvate (PEP) carboxylase increased. Changes in enzyme activities were associated with changes in the amount of enzyme proteins as determined by immunochemical analysis, sucrose density gradient centrifugation, and SDS gel electrophoresis of leaf extracts. Young developing leaves of plants which received high amounts of NO ₃ ^- during growth contained about 30% of the total soluble protein in the form of RuBP carboxylase; this value declined to about 17% in mature leaves. The level of PEP carboxylase in young leaves of plants at high NO ₃ ^- was an estimated 1% of the total soluble protein and increased to approximately 10% in mature leaves, which showed maximum capacity for dark CO₂ fixation. The growth of plants at low levels of NO ₃ ^- decreased the content of soluble protein per unit leaf area as well as the extractable activity and the percentage contribution of both RUBP carboxylase and PEP carboxylase to total soluble leaf protein. There was no definite change in the ratio of RuBP carboxylase to PEP carboxylase activity with a varying supply of NO ₃ ^- during growth. It has been suggested (e.g., Planta 144, 143–151, 1978) that a rhythmic pattern of synthesis and degradation of PEP carboxylase protein is involved in the regulation of -carboxylation during a day/night cycle in CAM. No such changes in the quantity of PEP carboxylase protein were observed in the leaves of Kalanchoe pinnata (Lam.) Pers. or in the leaves of the inducible CAM plant Mesembryanthemum crystallinum L.Abbreviations CAM Crassulacean acid metabolism - RuBP ribulose 1,5-bisphosphate - PEP phosphoenolpyruvate - G-6-P glucose-6-phosphate     

Sensitivity analysis of a mathematical model of phytoplankton growth and nutrient distribution in the Pacific Ocean off the northwestern U.S. coast

Equations (1), (2), and (3) on page 269 of the above paper shouldread:      

Bacterial metabolism of corticoids with particular reference to the 21-dehydroxylation.

Clostridium paraputrificum, an obligate anaerobe recovered from human feces, reduces the alpha,beta-unsaturated carbonyl of deoxycorticosterone, corticosterone, cortisone, and cortisol. The same steroids are 21-dehydroxylated by Culture 116, recently isolated from human feces, and by a closely related organism, Eubacterium lentum. The 21-dehydroxylase has no effect on hydroxyl groups at carbon atoms 11 and 17.