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91.
Lars Ährlund-Richter Ann-Charlotte Wikström Torbjörn Ramqvist Eva Klein 《Cellular immunology》1984,86(2):575-582
The T-cell subset mediating tumor graft neutralization was characterized in a methylcholanthrene (MC) tumor system. Lyt 1+ cells were critical for the successful prevention of outgrowth of the tumor cells in graft neutralization assays with irradiated recipients. Elimination of Lyt 1+ cells abolished the outgrowth inhibitory effect exerted by T-cell-enriched populations derived from syngeneic or semisyngeneic mice immunized with the H-2-carrying MC-induced M-A tumor. In accordance, lymphocyte populations containing 98% Lyt 1+ cells derived from M-A-immune mice, mediated a complete transplantation immunity against this tumor. When the immune T cells admixed to the tumor inoculum were syngeneic to the recipient (i.e., A-derived cells were transferred to A recipients, or F1 to F1), elimination of the Lyt 2+ cells did not influence the potential to inhibit tumor outgrowth. The presence of Lyt 1+2? cells were thus necessary, and sufficient, in the syngenic combination. A reduction of the graft-inhibiting potential occurred after elimination of Lyt 2+ cells from the A-derived M-A immune T-cell population when the recipients were semisyngeneic (i.e., (A/Sn X A.SW)F1, (A/Sn X CBA)F1, or (A/Sn X C57Bl/6)F1). Consequently, only in the semisyngeneic, but not in the syngeneic combinations, was the transfer of Lyt 2+ cells necessary for optimal graft inhibition. It can be concluded that the genotypic relation between the donor and the recipient influences the prerequisites of the tumor cell neutralization. 相似文献
92.
Jan Dahmén Torbjörn Frejd Göran Magnusson Ghazi Noori Anne-Sofie Carlström 《Carbohydrate research》1984,127(1):27-33
Enzymic hydrolysis of pullulan, followed by acetylation and chromatography, gave acetylated alpha-D-Glcp-(1----6)-alpha-D-Glcp-(1----4)-alpha-D-Glcp-(1----4)-D-Glcp which, with 2-bromoethanol and boron trifluoride etherate in dichloromethane, gave the 2-bromoethyl glycoside. The reactions of the glycoside with methyl 3- mercaptopropionate , methyl 11- mercaptoundecanoate , and octadecanethiol are described, and also its hydrogenolysis to give an ethyl glycoside. The mercaptopropionate -derived, spacer-arm glycoside has been coupled to bovine serum albumin and keyhole limpet haemocyanin. 相似文献
93.
Torbjörn Friberg 《Culture, medicine and psychiatry》2009,33(4):538-558
This article aims to understand how burn-out became an object of thought, through the study of certain processes of legitimization. It traces the genealogy of the burn-out concept from the initial article from 1974, via its confirmation as a “disease” in the 1980s, to its appearance as a legitimate diagnosis in Sweden in 1997. The theoretical framework is that of applied metaphysics, which means a study on how a specific phenomenon came into being. Consequently, I take departure from ontology in motion with an approach that concerns the legitimization processes. The conclusion will show the underlying processes of legitimization in relation to the making of a psychiatric object of thought in Swedish society. 相似文献
94.
Kristoffer S?berg Tore Jahnsen Torbj?rn Rognes Bj?rn S. Sk?lhegg Jon K. Laerdahl 《PloS one》2013,8(4)
3′,5′-cyclic adenosine monophosphate (cAMP) dependent protein kinase or protein kinase A (PKA) has served as a prototype for the large family of protein kinases that are crucially important for signal transduction in eukaryotic cells. The PKA catalytic subunits Cα and Cβ, encoded by the two genes PRKACA and PRKACB, respectively, are among the best understood and characterized human kinases. Here we have studied the evolution of this gene family in chordates, arthropods, mollusks and other animals employing probabilistic methods and show that Cα and Cβ arose by duplication of an ancestral PKA catalytic subunit in a common ancestor of vertebrates. The two genes have subsequently been duplicated in teleost fishes. The evolution of the PRKACG retroposon in simians was also investigated. Although the degree of sequence conservation in the PKA Cα/Cβ kinase family is exceptionally high, a small set of signature residues defining Cα and Cβ subfamilies were identified. These conserved residues might be important for functions that are unique to the Cα or Cβ clades. This study also provides a good example of a seemingly simple phylogenetic problem which, due to a very high degree of sequence conservation and corresponding weak phylogenetic signals, combined with problematic nonphylogenetic signals, is nontrivial for state-of-the-art probabilistic phylogenetic methods. 相似文献
95.
96.
Summary In butterflies and many other insects there is a general tendency for males to emerge before females. This is known as protandry. In this paper we advance the hypothesis that protandry is a reproductive strategy of males, resulting from competition for mates, and should primarily occur in species maintaining female monogamy. Our hypothesis is corroborated by applying a mathematical treatment to a theoretical population with seven defined properties, all of which are argued to be reasonable assumptions for natural populations. 相似文献
97.
Summary The fluorescence histochemical method of Falck and Hillarp for the cellular localisation of biogenic amines was used to follow the disappearance and reappearance of peripheral noradrenergic nerves in the chick after treatment with 6-hydroxydopamine. With certain exceptions, it seemed that the disappearance and reappearance of the nerves was due to their degeneration and subsequent regeneration. However, there was not a uniform destruction of the noradrenergic nerves associated with different effector tissues. The extent of degeneration was greater in older than in younger chicks following equivalent doses of the drug, possibly indicating a greater uptake efficiency of the older nerves. It appeared that the noradrenergic nerves in the younger chicks regenerated more rapidly than those of older chicks, but in none of the animals studied were there any obvious morphological modifications of the regenerating nerves.The major part of this work was carried out in the Department of Zoology, Melbourne University, Australia.We are grateful to Professor G. Burnstock for use of laboratory facilities, and to the National Heart Foundation of Australia for financial support. 相似文献
98.
Hydrobiologia - While many studies provide microscale relationships between fish and habitat characteristics, studies covering longer river reaches are scarce. Modern remote sensing... 相似文献
99.
Linear poly(urethane urea) containing a biodegradable soft segment and a hard segment built solely from methyl-2,6-diisocyanatehexanoate (LDI) is presented, using a procedure where no chain extender is required. By having LDI in excess, together with a soft segment, and adding water in the vapor phase continuously creates amines in situ resulting in hard segments containing multiple LDI units linked via urea linkages. As soft segments, polymers of trimethylene carbonate (TMC) and copolymers of TMC, epsilon-caprolactone, and D,L-lactic acid (DLLA) were used. High inherent viscosity, 0.95-1.65 dL/g, was afforded even when DLLA-containing soft segments were used, which usually undergo aminolysis. With a hard segment content between 12% and 18%, all of the materials showed very high elongation at breakage, ranging from 1600% to 4700%, and an elastic modulus from 2.1 to 140 MPa. This one-pot synthesis is simple and has now been shown to be applicable to a large number of systems. 相似文献
100.