Stimulation of dopamine synthesis and release by morphine and D-Ala2-D-Leu5-enkephalin in the mouse striatum in vivo

The effects of opiates on dopamine (DA) release and synthesis were assessed in the mouse striatum $\text{in vivo}$ by simultaneously measuring 3,4-dihydroxyphenylalanine (DOPA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels after inhibition of aromatic amino acid decarboxylase. This method was developed to assess stimulus-coupled changes in DA synthesis and release. Peripheral injections of morphine and intraventrcular injections of D-Ala²-Leu⁵-enkephalin elevated DOPAC levels, indicating that “opiates” stimulated DA release. Concomitantly, the rate of DA synthesis was increased. The effects were dose-dependent, saturable and antagonized by naloxone. When morphine and the enkephalin analog were given together in saturating doses, the effects of the two agents were not additive. Thus, the involvement of different receptors in the mediation of the effects of morphine and enkephalins could not be demonstrated.     

Possibility of analytical application of the partition in aqueous biphasic polymeric systems technique

The partition behaviour of a number of ionic and nonionic surface-active substances in the dextran-polyethylene glycol system was examined. The strictly linear dependence of the logarithm of the partition coefficient on the alkyl chain length for a homologous series of nonionic surfactants provides a measure of the difference in the relative hydrophobicity between the two phases of the system, in terms of the free energy of transfer of a CH₂ group from the bottom phase to the top phase of the system. This difference is found to be altered in the presence of NaCl or KCl depending on the salt concentration. It is concluded that the influence of the salt composition of the system on the distributed solutes' behaviour may be due to the effect of the ions on the hydrophobicity difference between the phases.The partition of ionic amphiphiles is found to be dependent on the relative hydrophobicity of the compounds as well as on their charge. It is shown that at salt concentrations up to about 0.1 M NaCl the charged solute partition is determined by its charge as well as its relative hydrophobicity, in the presence of 0.1–0.2 M NaCl the substance distribution is highly dependent on its charge and slightly on its lipophility. At the salt concentrations above 0.2 M the solute partition is determined just by its hydrophobic character and seems to be totally independent of its charge. It is concluded that the partition technique can be used for analytical purposes. The method seems to be unique in providing quantitative information on the amphiphilic surface properties of the solutes being partitioned.     

The myofibroblast: Paradigm for a mechanically active cell

Tissues lose mechanical integrity when our body is injured. To rapidly restore mechanical stability a multitude of cell types can jump into action by acquiring a reparative phenotype—the myofibroblast. Here, I review the known biomechanics of myofibroblast differentiation and action and speculate on underlying mechanisms. Hallmarks of the myofibroblast are secretion of extracellular matrix, development of adhesion structures with the substrate, and formation of contractile bundles composed of actin and myosin. These cytoskeletal features not only enable the myofibroblast to remodel and contract the extracellular matrix but to adapt its activity to changes in the mechanical microenvironment. Rapid repair comes at the cost of tissue contracture due to the inability of the myofibroblast to regenerate tissue. If contracture and ECM remodeling become progressive and manifests as organ fibrosis, the outcome of myofibroblast activity will have more severe consequences than the initial damage. Whereas the pathological consequences of myofibroblast occurrence are of great interest for physicians, their mechano-responsive features render them attractive for physicists and bioengineers. Their well developed cytoskeleton and responsiveness to a plethora of cytokines fascinate cell biologists and biochemists. Finally, the question of the myofibroblast origin intrigues stem cell biologists and developmental biologists—what else can you ask from a truly interdisciplinary cell?     

Mitochondrial haplogroup N1a phylogeography,with implication to the origin of European farmers

Background  

Tracing the genetic origin of central European farmer N1a lineages can provide a unique opportunity to assess the patterns of the farming technology spread into central Europe in the human prehistory. Here, we have chosen twelve N1a samples from modern populations which are most similar with the farmer N1a types and performed the complete mitochondrial DNA genome sequencing analysis. To assess the genetic and phylogeographic relationship, we performed a detailed survey of modern published N1a types from Eurasian and African populations.     

Über die direkte und indirekte Strahlenwirkung auf Enzyme in der Zelle

Zusammenfassung Es wurde die Röntgenstrahleninaktivierung von Laktatdehydrogenase in Rattenleber und Invertase in Hefe untersucht. Die Inaktivierung war in den feuchten lebenden Zellen und in den getrockneten Zellen praktisch gleich, obwohl ein Beitrag der indirekten Strahlenwirkung in den feuchten Zellen zu erwarten war.Auszugsweise vorgetragen auf dem XI. Internationalen Kongreß für Radiologie, Rom, September 1965