Protein synthesis during the secondary developmental transition of the embryonic rat pancreas.
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Ammonium Sulfate↗
Biomedical subjects
B T Walther
Publications and source records attributed to B T Walther.
The development of the dorsal and ventral mammalian pancreas in vivo and in vitro.
The origin, morphogenesis, and biochemical differentiation of the dorsal and ventral pancreas of the rat embryo have been investigated in order to ascertain the similarities and dissimilarities between the two lobes. We have utilized a culture system in which the primitive gut gives rise to a number of differentiated organs, including the dorsal and ventral pancreas. The two pancreases do not undergo fusion in these cultures, thus allowing independent analyses of the two lobes for comparison with in vivo results. The dorsal pancreas first appeared at the 23-25 somite stage while the ventral pancreas appeared approximately 12 hr later at the 29-30 somite stage. Guts from embryos as young as 12 somites were capable of developing both pancreases in vitro. In spite of the 12 hr difference between the times of their appearance, the dorsal and ventral pancreases exhibited identical patterns of morphological and biochemical differentiation. The two lobes contained the same exocrine enzymes and hormones, at similar levels, differing only in their glucagon content, the dorsal pancreas possessing a fivefold higher glucagon specific activity. The implications of these results are discussed.
Amylases↗
Brief uncontrollable stress and psychological parameters influence human plasma concentrations of IgM and complement component C3.
Thirty-eight men participated in a study of immunological, hormonal, and psychological parameters before and after acute stress situations. A brief but acute stress was repeated daily for 4 days. This exposure caused the plasma levels of IgM and C3 to increase from Basal Day to Experimental Day 4. Significant correlations between endocrine and immunological parameters, and also between psychological measures and immunological parameters, were found. Use of psychological defense was related both to endocrine and immunological changes. The authors concluded that psychological stress may influence immunological functions both indirectly, by hormonal changes, and directly, by nervous regulation during brief but acute stress periods.
Adult↗