β-glucuronidase activity in the liver of infant mammals

Zusammenfassung Niedrige Leber--Glucuronidase (Phenolphthaleinglucuronid-Substrat) neugeborener Ratten steigt in der dritten Woche auf Erwachsenenwerte. Die Aktivität sinkt bei Meerschweinchen von der Geburt an, steigt bei Kaninchen zwischen Geburt und drittem Lebenstag und zeigt bei Mäusen während der postnatalen Entwicklung geringe Schwankungen.     

Collagen synthesis by human bone marrow fibroblasts

Collagen synthesis was measured in fibroblast cultures derived from normal and acute lymphoblastic leukemia (ALL) bone marrow. Collagen production was higher in normal than in ALL fibroblasts. These cells elaborate type I and type III procollagens in a ratio that depends on cell density and whether cells originate from normal or ALL bone marrow.     

Radiation-induced changes in gentamicin pharmacokinetics

Summary Decreased clearance of i.v. or intratracheally administered gentamicin was observed in rats following single whole-body irradiation, 6 Gy⁶⁰Co, reaching its lowest rate on the 7th post-irradiation day. Simultaneously the absorption rate of gentamicin from the lungs was found to be increased.     

Early and selective increase in brain dopamine levels after axotomy

Résumé Nous avons étudié les concentrations de dopamine et de noradrénaline du prosencéphale après lésion unilatérale des neurones monoaminergiques correspondants. Les deux méthodes employées soit biochimique et histochimique ont mis en évidence sensiblement le même phénomène, à savoir: une augmentation importante et rapide du taux de dopamine entre 15 min et 24 h suivie d'une chute due selon toutes probabilités à la dégénerescence axonale. Quand à la noradrénaline, seule la deuxièmephase, la chute, a pu être observée.     

The influence of phytochrome in the water exchange of epidermal cells ofTaraxacum officinale

Résumé La qualité de la lumière a modifié le passage de l'eau dans les cellules épidermiques des pétioles deTaraxacum officinale. L'irradiation par du rouge sombre a augmenté la rapidité avec laquelle l'eau entre dans la cellule et la lumière rouge clair a renversé cet effet.     

Liver regeneration after partial hepatectomy in rats exposed before the operation to the stress stimulus

Zusammenfassung Es wird nachgewiesen, dass bei Ratten, die 8 h vor partieller Hepatektomie einer Stress-Stimulation ausgesetzt wurden, die Intensität der DNS-Synthese postoperativ im Vergleich mit den Kontrolltieren grösser war. Ebenso waren Veränderungen des Lebergewichtes und des Triglyzeridinhaltes in der Leber nach der partiellen Hepatektomie dieser Ratten stärker ausgeprägt. Vergleichbare Resultate wurden auch bei Ratten gefunden, die in der gleichen Zeit vor der partiellen Hepatekto'mie eine ACTH-Injektion erhielten.     

Detection and substitution-pattern determination of guanidines

Summary The guanidine function can be detected and its substitution pattern determined taking into account the¹H-NMR signals of the N–H and N–C–H groups. Satisfactory results were obtained with mono-to penta-substituted guanidines (as picrate salts).Part XX ofStudies on Plants; preceding part,R. A. Corral, O. O. Orazi andI. A. Benages, Tetrahedron29, 205 (1973).     

The scene for Interpretive Systemology

In this introductory paper to the special issue ofSystems Practice devoted to Interpretive Systemology, some of the conditions under which this trend in systems thinking has come to life are briefly depicted. For that purpose a wider and a narrower scene are presented. The wider scene presents the general questions and problems that are to be tackled by Interpretive Systemology, within a wide international perspective of systems thinking and practice. The narrower scene, which is related to more particular conditions, shows how some circumstances connected to the socalled Third World or underdeveloped countries have helped to trigger the launching of Interpretive Systemology. Finally, a brief outline of the research program for Interpretive Systemology is introduced.     

The role of histones and their modifications in the informative content of chromatin

It is traditionally accepted that the DNA sequence cannot by itself explain all the mechanisms necessary for the development of living beings, especially in eukaryotes. Indeed part of the information used in these processes is stored in other ways, generally called epigenetic, whose molecular mechanisms are mostly unknown. The ultimate explanation for them might reside in the non-DNA moiety of chromatin which may play an active role in heredity (chromatin information). Histones are the universal structural component of chromatin. However, recent studies strongly suggest that histones, and their modifications — especially the reversible acetylation of lysines — may act as a recognition signal for regulatory proteins and they may participate, for this reason, in gene regulation. This type of information could be maintained through its replication and, ultimately, it could form the molecular basis of certain processes related to the development of the eukaryotic organisms.