The effect of calcitonin on calcium uptake in mouse molars in vitro

Summary Mouse maxillary second molars were removed at either 24 or 96 h of age and maintained in vitro. Half of the teeth, of each age group, were treated with 50 m-units of synthetic salmon calcitonin. By comparing the initial and final calcium concentrations in the medium, the net uptake or release of calcium was inferred. The treated molars took up significantly more calcium than the untreated groups.     

Possible effect of caerulein on calcitonin secretion in man.

Caerulein, infused in normal subjects, significantly reduces serum Calcium levels; in addition, when infused 60 or 90 min after radioactive calcium, it increases the specific plasma radioactivity, in a manner similar to calcitonin. These results suggest that in man caerulein stimulates calcitonin release.     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin from Salmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (BCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

Summary The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin fromSalmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (GCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

The effect of polyphloretin phosphate,polyoestradiol phosphate,a diphosphonate and a polyphosphate on calcification induced by dihydrotachysterol in skin,aorta and kidney of rats

Zusammenfassung Zwei Phosphatasehemmer (Polyphloretinphosphat und Polyoestradiolphosphat), ein Polyphosphat (Hexametaphosphat) und ein Diphosphonat (Ethan-1-hydroxy-1,1-diphosphonat) wurden auf ihre Fähigkeit untersucht, Verkalkungen zu verhindern, welche in der Haut, der Aorta und den Nieren von Ratten durch Dihydrotachysterol (DHT) hervorgerufen wurden. Das Diphosphonat erwies sich als der stärkste Hemmer; dann folgten das Polyphosphat und die zwei Phosphatasehemmer. Die Phosphatasehemmer wurden zusätzlich auf ihre Fähigkeit geprüft, die Calciumphosphat-Ausfällung in vitro zu verlangsamen. Polyphloretinphosphat besitzt diese Fähigkeit bei Konzentrationen von 10^–5 M und mehr; Polyoestradiolphosphat ist unwirksam.

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Acknowledgments. This work has been supported by the Swiss National Fund, Grant No. 4564, the U.S. Public Health Service, Grant No. 07266, AB Leo, Hälsingborg, Sweden, and Procter and Gamble Company, Cincinnati, USA.     

The opsins of the vertebrate retina: insights from structural,biochemical, and evolutionary studies

The vertebrate retina contains several classes of visual pigments responsible for such diverse functions as image- and nonimage-forming vision, the entrainment of circadian cycles, and the pupilary light response. With vision being vital to the survival of many species, the elucidation of the structural and biochemical properties of visual pigments has been the focus of a large body of research that has led to rapid advances in the field of photoreception. In this review, the current understanding of the structure, function, biochemistry, and evolution of the opsins that make up the photopigments in the vertebrate retina will be reviewed. These include the rod and cone opsins, melanopsin, RGR, peropsin, and VA-opsin. The goal is to highlight important questions that have been answered and to define some of the remaining questions in the field that will provide future directions for research.     

The mechanical and biochemical effects of pentoxifylline on the perfused rat heart

Perfusion of the isolated rat heart at constant heart rate and coronary flow with the inhibitor of cyclic nucleotide phosphodiesterase, pentoxifylline (10(-4) moles/l), produced no significant effect on the maximum rate and the peak of contraction, but increased the maximum rate of relaxation. cAMP level and cAMP-dependent protein kinase activity were increased in the absence of changes in cGMP. The results were identical in hearts of reserpinized rats.     

The mechanical and biochemical effects of pentoxifylline on the perfused rat heart

Summary Perfusion of the isolated rat heart at constant heart rate and coronary flow with the inhibitor of cyclic nucleotide phosphodiesterase, pentoxifylline (10^–4 moles/l), produced no significant effect on the maximum rate and the peak of contraction, but increased the maximum rate of relaxation. cAMP level and cAMP-dependent protein kinase activity were increased in the absence of changes in cGMP. The results were identical in hearts of reserpinized rats.This work was supported by grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas and the Comisión de Investigaciones Científicas. Buenos Aires, Argentina.We thank Hoechst Laboratories for the partial support and Mrs Alicia R. Ramirez and María Prinzo for the excellent technical assistance.     

The effect of the adrenal cortex and diet composition on the rate of acetoacetate formation by liver slices from infant and adult rats

Zusammenfassung Hoher Acetoacetatanteil in Leber junger Ratten wird durch Kortikosteronverabreichungin vivo am 10. Tag nach Geburt erniedrigt. Bei erwachsenen Ratten kein Hormoneinfluss. Adrenalektomie (14. Tag nach Geburt) führt zu hoher Produktion (19. Tag). Nur bei erwachsenen, nicht hungernden Ratten ist dies weniger ausgeprägt.