Survival of satellite cells in whole muscle transplants

The ability of satellite cells to survive the ischemic conditions at the core of orthotopically free grafted rat extensor digitorum longus muscles was examined. Cell cultures of isolated core and peripheral regions of whole muscle grafts maintained in vivo for more than 24 hours indicated that no viable cells were present in the core, whereas the number of cells from the peripheral region was greatly increased. Muscles were examined with the electron microscope to determine the fate of satellite cells of the core at various times after transplantation. The population of satellite cells in the core was reduced beginning at 18 hours and had virtually disappeared by 24-28 hours. This reduction did not appear to be the result of satellite cell death. Although there was abundant morphological evidence that myonuclei as well as myofiber cytoplasmic organelles were degenerating, there was little indication of satellite cell death in situ any time period studied. These studies suggest that satellite cells cannot survive, but migrate from the ischemic core to more peripheral regions of whole muscle transplants. In addition, they suggest that migration is an important aspect of the regeneration response in the free graft system and permits the myogenic population to contribute en masse to the centripetal wave of regeneration from the time it is initiated at the muscle periphery.     

Cellular mechanisms of T cell mediated drug hypersensitivity

Noncovalent drug presentation leads to the activation of drug-specific T cells. In some patients with hypersensitivity, such a response occurs within hours even upon the first exposure to the drug. Thus, the reaction to the drug might not be due to a classical, primary response, but rather mediated by existing, preactivated T cells that are cross specific for the drug, and have an additional (peptide) specificity as well.     

Haarnadelgegenstromprinzip als Grundlage der Harnkonzentrierung in der Niere

Ohne ZusammenfassungVortrag anläßlich der Überreichung der Urkunde eines Dr. med. h. c. der medizinischen Fakultät der Universität Kiel, gehalten vor der Kieler Medizinischen Gesellschaft und dem Ortsverband Kiel der Gesellschaft Deutscher Chemiker am 5. Mai 1959.Aus dem Physikalisch-Chemischen Institut der Universität Basel, Direktor: Prof. Dr.W. Kuhn.     

Messungen zum Aggregationsverhalten perfluorierter Alkansäuren

With the use of various techniques an attempt was made to characterize the aggregates that exist in micellar surfactant solutions of salts of the perfluornonanoic acid. The cmc values of the investigated systems were determined by conductivity and surface tension measurements. Conclusions about the shape of the micellar aggregates were drawn from rheologic and electric birefringence measurements. For the lithium, the ammonium and the tetramethylammonium surfactants the existence of normal micelles with spherical shape and with all surfactant ions lying at the micellar surface was found. The perfluornonanoate surfactants with the ammonium counterions that are partially substituted by alkyl groups showed in all investigations a behaviour that was different from the normal case. It was postulated that these solutions contain emulsion-droplet-like giant micelles with the surfactant ions and counterions solubilized as ion pairs in the interior of the micelles. Some of these giant micelles do not have spherical shape; these solutions showed electric birefringence. In most cases the giant micelles disappeared at higher temperatures. Only normal small micelles with spherical symmetry could then be detected and the measured values were again in the range for values of normal C₈-perfluordetergents. On the basis of the investigated systems reasons and models for the formation of giant micelles are discussed.     

Molecular analysis of streptogramin resistance in enterococci

The new semi-synthetic streptogramin antibiotic combination quinupristin/dalfopristin (Synercid) is a promising alternative for a treatment of infections with multiple resistant gram-positive pathogens, e.g. glycopeptide- and multi-resistant Enterococcus faecium. Streptogramins consist of two unrelated compounds, a streptogramin A and B, which act synergistically when given in combination. Mechanisms conferring resistance against both components are essential for resistance against the combination in E. faecium. In this species resistance to streptogramin A compounds is mediated via related acetyltransferases VatD and VatE. Resistance against streptogramins B is either encoded by the widespread ermB gene cluster conferring resistance to macrolide-lincosamide-streptogramin B antibiotics or via expression of the vgbA gene, which encodes a staphylococcal-type lactonase. E. faecalis is intrinsically resistant to streptogramins. Due to a wide use of streptogramins (virginiamycins S/M) in commercial animal farming a reservoir of streptogramin-resistant E. faecium isolates had already been selected. Determinants for streptogramin resistance are localized on plasmids that can be transferred into an E. faecium recipient both in vitro in filter-matings and in vivo in the digestive tracts of rats. Hybridization and sequencing experiments revealed a linkage of resistance determinants for streptogramins A and B on definite plasmid fragments.     

Chemotherapieinduzierte Veränderungen bei hochmalignen zentralen Osteosarkomen

High-grade central osteosarcomas are the most frequent malignant bone neoplasms in childhood and adolescence. Their prognosis has been substantially improved using neoadjuvant chemotherapy. The morphological examination of surgical specimens reveals important information regarding the success of treatment. The histological determined degree of regression represents one of the most reliable therapy-related prognostical factor. Thus pathological analysis of the surgical specimens is of great importance notwithstanding the improved clinical and radiological diagnostic of osteosarcoma.     

Age-dependent alterations of microtubule-associated enzyme activities from bovine brain (protein kinase, adenosine triphosphatase, guanosine triphosphatase)

Microtubules have been isolated from immature (3-4 weeks' old) and old (11-13 years' old) bovine brains. Quantitative studies revealed that the concentration of extractable microtubule protein per gram of wet brain decreased from 0.47 mg (immature animals) to 0.34 mg (old animals). The major components of microtubule protein (tubulin and high-molecular-weight microtubule-associated proteins) do not undergo an age-correlated change. Determination of the endogenous protein kinase activity revealed that the activity associated with "immature" calf brain microtubules was six times higher than the activity present in "old" preparations. In contrast, the stimulatory effect of cyclic AMP on protein phosphorylation in microtubules from old bovine brains exceeds nine-fold the value obtained from immature animals. After addition of casein (exogenous acceptor), the basal activities increased in both preparations without altering the age-correlated difference in the specific activity. By comparing the radioactivity pattern of sodium dodecyl sulfate polyacrylamide gels after autophosphorylation of microtubule protein with [gamma-32P]ATP, 1.5 moles of phosphate per mole of high-molecular-weight microtubule-associated protein were estimated to be incorporated in preparations from immature animals and 0.9 mole of phosphate per mole of associated protein in the experiments with "old" microtubule protein. Adenosine triphosphatase activity, associated with the high-molecular-weight microtubule-associated protein 1, was determined to be 15% reduced in preparations from old animals, compared to the activity in "young" preparations. In contrast, the guanosine triphosphatase activity increased five-fold during ageing; the higher activity of this enzyme was observed both during the initial and the steady-state phases of microtubule formation.