Dietary restriction and fetal development

Summary The effect of deficient nutrition of pregnant Wistar rats on the fetal weight has been studied. It has been established that the fetal weight of the group of rats fed with a restricted amount of stock diet lags behind the fetal weight of the group receiving unrestricted amounts of the same stock diet. The differences in weight between the 2 groups were, on each day of the observation period, significant at the level of p<0.05 and p<0.01, respectively.This work was supported by a grant of the Republic Research fund of Croatia No. 18-04-06/19-1975.     

Origin and development of neuroepithelial bodies in fetal rabbit lungs

Summary Light-microscope studies concerning the embryological development of fetal rabbit lungs revealed the occurrence of argyrophilic neuroepithelial bodies in an early gestational stage (i.e. already in the glandular period and from the 18th day onwards). Their morphological characteristics and further differentiation towards birth are detailed.Supported by a grant from the Nationaal Fonds voor Wetenschappelijk Onderzoek — Fonds voor Geneeskundig Wetenschappelijk Onderzoek (Belgium). We thank E. Swinnen. H. Van den Bosch and M.R. Van hamme for technical, G. Pison for photographical and L. Lauwers for secretarial assistance.     

Loss of FrmA leads to increased cell-cell adhesion and impaired multi-cellular development of Dictyostelium cells

Cell-cell adhesion is a critical property of all multi-cellular organisms and its correct regulation is critical during development, differentiation, tissue building and maintenance, and many immune responses. The multi-talin-like FERM domain containing protein, FrmA, is required during starvation-induced multi-cellular development of Dictyostelium cells. Loss of FrmA leads to increased cell-cell adhesion and results in impaired multi-cellular development, slug migration and fruiting bodies. Further, mixing experiments show that FrmA null cells are excluded from the apex of wild-type mounds, to which cells that normally form the organising centre known as the tip sort. These data suggest a critical role for FrmA in regulating cell-cell adhesion, multi-cellular development and, in particular, the formation of the organising centre known as the tip. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 28 August 2008; received after revision 10 October 2008; accepted 21 October 2008     

Ontogenic development of peptide hormones in the mammalian fetal pancreas

Summary The ontogeny of insulin, glucagon, PP and somatostatin in the mammalian fetal pancreas has been examined in recent years largely by immunocytochemistry and in some instances by radioimmunoassay. Complete ontogenic data are available only for the rat, human pig and sheep. Figure 3 compares the time of appearance of the endocrine cell-types within the fetal pancreas when the periods of gestation of the four species are converted to a uniform scale. The striking ontogenic difference in the rat probably reflects the immaturity of the rodent fetus at birth compared with the human, pig and sheep. In the fetal pancreas, differences in cell number of glucagon and PP cells in the dorsal and ventral lobes become apparent from an early gestational period. Factors responsible for the functional and structural maturation of the fetal pancreatic endocrine cells and the processes involved in pancreatic organogenesis are poorly understood. Studies in these areas would have clinical implications since it may be possible in the future to employ agents for selective replication of fetal -cells for transplantation in patients with Type I diabetes, bearing in mind that such cells must have the capacity to respond to normal stimuli and repressors when transplanted. The presence of the other islet cell-types may be obligatory for these appropriate responses. This would require a more complete knowledge of those factors which produce the normal selectivity of the four hormonal cell-types.     

Ontogenic development of peptide hormones in the mammalian fetal pancreas

The ontogeny of insulin, glucagon, PP and somatostatin in the mammalian fetal pancreas has been examined in recent years largely by immunocytochemistry and in some instances by radioimmunoassay. Complete ontogenic data are available only for the rat, human, pig and sheep. Figure 3 compares the time of appearance of the endocrine cell-types within the fetal pancreas when the periods of gestation of the four species are converted to a uniform scale. The striking ontogenic difference in the rat probably reflects the immaturity of the rodent fetus at birth compared with the human, pig and sheep. In the fetal pancreas, differences in cell number of glucagon and PP cells in the dorsal and ventral lobes become apparent from an early gestational period. Factors responsible for the functional and structural maturation of the fetal pancreatic endocrine cells and the processes involved in pancreatic organogenesis are poorly understood. Studies in these areas would have clinical implications since it may be possible in the future to employ agents for selective replication of fetal beta-cells for transplantation in patients with Type I diabetes, bearing in mind that such cells must have the capacity to respond to normal stimuli and repressors when transplanted. The presence of the other islet cell-types may be obligatory for these appropriate responses. This would require a more complete knowledge of those factors which produce the normal selectivity of the four hormonal cell-types.     

Kinins and kininogen in endotoxin shock

Résumé Aucune quantité détectable de kinines ne fut trouvée après administration d'endotoxine et l'on n'obtint pas de différence significative dans le contenu plasmatique en kininogènes après l'injection. Nos résultats n'attribuent aux kinines aucune participation significative à l'hypotension du choc endotoxique.

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Supported in part by a grant of the Consejo Nacional de Investigaciones Científicas y Técnicas (CNICT), Argentina.     

Bacterial chemoreceptors and chemoeffectors

Bacteria use chemotaxis signaling pathways to sense environmental changes. Escherichia coli chemotaxis system represents an ideal model that illustrates fundamental principles of biological signaling processes. Chemoreceptors are crucial signaling proteins that mediate taxis toward a wide range of chemoeffectors. Recently, in deep study of the biochemical and structural features of chemoreceptors, the organization of higher-order clusters in native cells, and the signal transduction mechanisms related to the on–off signal output provides us with general insights to understand how chemotaxis performs high sensitivity, precise adaptation, signal amplification, and wide dynamic range. Along with the increasing knowledge, bacterial chemoreceptors can be engineered to sense novel chemoeffectors, which has extensive applications in therapeutics and industry. Here we mainly review recent advances in the E. coli chemotaxis system involving structure and organization of chemoreceptors, discovery, design, and characterization of chemoeffectors, and signal recognition and transduction mechanisms. Possible strategies for changing the specificity of bacterial chemoreceptors to sense novel chemoeffectors are also discussed.     

Shwartzman phenomenon without endotoxin preparation

Zusammenfassung Kasein, Pepton bzw. Baktokasiton wurde als präparierende Erstinjektion für lokalisiertes Shwartzman-Phänomen an Kaninchen verwendet. Nach provozierender i.v. Endotoxininjektion kommt es zum typischen Shwartzman-Phänomen. Da die verwendeten Substanzen Chemotaxis von Leukozyten verursachen, ist anzunehmen, dass die an Stelle der präparierenden Injektion angesammelten Leukozyten in der Ausbildung des Shwartzman-Phänomens eine vorwiegende Rolle spielen.     

Lack of endotoxin effect on the microcirculation after pretreatment with detoxified endotoxin (endotoxoid)

Zusammenfassung Die Endotoxin-bedingten Störungen an der Mikrozirkulation — geprüft an der Hamsterbackentasche und dem Meerschweinchenmesenterium — bleiben aus, wenn den Tieren 24 h zuvor detoxifiziertes Endotoxin verabreicht wurde.     

Dithiols simulate endotoxin in theLimulus reaction

Summary Dithiothreitol, dithioerythritol and bacterial lipopolysaccharides increase optical absorbance and clotLimulus lysate. Purification of dithiothreitol from possible endotoxin contamination by vacuum sublimation or chromatography does not abolish the reaction with lysate. The dithiols reported active here represent the smallest molecules capable of simulating endotoxin in theLimulus test.Acknowledgments. This investigation was supported by grant No. P30 14194 and CA 12635, awarded by the National Cancer Institute, Dhew.