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  • 1
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The ccd locus of the F plasmid codes for two gene products, CcdA and CcdB, which contribute to the plasmid's high stability by post-segregational killing of plasmid-free bacteria. Like the quinolones, the CcdB protein is a poison of the DNA-topoisomerase II complexes, while CcdA acts as an antidote against CcdB. in addition to these poison-antipoison properties, the CcdA and CcdB proteins act together at transcription level to repress their own synthesis. In this work, we have isolated, in vivo., and characterized several non-killer CcdB mutants. All missense mutations which inactivate CcdB killer activity are located in the region coding for the last three C-terminal residues. However, the resulting mutant CcdB proteins retain their auto-regulatory properties. We conclude that the last three C-terminal residues of CcdB play a key role in poisoning but are not involved in repressor formation.
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  • 2
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract To define the polymorphism and extent of the mouse immunoglobulin kappa (Igk) gene complex, we have analyzed restriction-enzyme digested genomic DNA from 33 inbred strains of mice with labeled DNA probes corresponding to 16 V x protein groups (1 of them previously undescribed) and the J k/C K region (V, variable; J, joining; C, constant). These probes detected between 1 and 25 distinct restriction enzyme fragments (REF) that appeared in up to eight polymorphic patterns, thus defining eight mouse Jgk haplotypes. The investigated portion of the V A repertoire was estimated to encompass between 60 and 120 discernable V k gene-containing REFs. In contrast to mouse V H gene families, several V k gene families defined by these probes appeared to overlap. This observation has implications for V k gene analyses by nucleic acid hybridization and raises the possibility that the V A gene complex is a continuum of related sequences.
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  • 3
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Probands from 26 PKU-affected families of the Berlin area were analyzed with respect to the allele frequency distribution of six RFLPs in linkage with the normal and the PKU alleles of the phenylalanine hydroxylase gene. These investigations confirm most of the RFLP haplotypes observed by Güttler and colleagues in the Danish population and describe two additional ones. They detect no significant differences in the single RFLP or RFLP haplotype distribution on the normal chromosomes in comparison with the Danish families and confirm a prevalent association of the RFLP haplotypes 1,4 and 7 with the normal PAH allele. In contrast to the Danish investigations, in our study the PKU allele is found most frequently linked to haplotype 2, rather then to haplotype 3. In one of our patients we found a substitution of the normal 19-kb MspI fragment by a 13.5- and a 5.5-kb fragment, reported up to now only in one other German family.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Der Onkologe 3 (1997), S. 99-104 
    ISSN: 1433-0415
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 5
    ISSN: 1432-2277
    Keywords: Experimental liver transplantation ; Living donor ; Heterotopic graft ; Primates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The need for liver grafts is critical in countries where brain death is not accepted as a legal criterion for organ retrieval. This experimental study was conducted with nonhuman primates in order to evaluate the feasibility of liver transplantation using a living donor. An original technique was employed to remove the left part of the liver from the donor: transection of the parenchyma was done while the blood flow was kept to the left part of the liver. In the recipients, the graft was placed heterotopically. No blood transfusions were administered to donors or recipients. In spite of a few failures, due to consequences of intraoperative bleeding, several donor operations using this original technique were successful, in the immediate postoperative period as well as several months later. Among the recipients, the large number of early failures suggests that the heterotopic position is probably not the appropriate one and that orthotopic transplantation should be preferred.
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  • 6
    ISSN: 1432-2196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 7
    ISSN: 1432-0509
    Keywords: Foreign bodies ; Sponges, towels ; Surgery, complications ; Abdomen. abscess ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The diagnosis of retained sponges and towels a year or more after surgery is often very difficult. We describe the computed tomographic (CT) findings in 4 patients with this complication; 2 cases of retained sponges and 2 cases of retained towels. While the CT appearance of the retained sponges was not specific, the particular appearance of the retained towels had not been previously described. This appearance is characteristic enough to suggest the correct diagnosis before reoperation.
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  • 8
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. The purpose of the present study was to test the effects of synthetic atrial natriuretic peptide (ANP) on renal haemodynamics and excretory capacities of salt and water in the rat during an ‘acute volumic stress’, which was induced by brisk disturbances of the circulatory volume.2. To this end, 29 anaesthetized male Wistar rats were rapidly injected with 1 mL of 0.85% NaCl, repeated twice at 60 s intervals. The injectates contained no ANP (n = 5) or 1 × 0.25 (n = 6), 3 × 0.25 (n = 6), 1 × 2.5 (n = 6) or 3 × 2.5 μg (n = 6) ANP, added to the first injectate only (1 ×) or to each injectate (3 ×). Renal blood flow (RBF) was continuously measured with an electromagnetic flow transducer.3. Renal blood flow increased transiently (approximately 30 s) by approximately 13% (P 〈 0.05) during each injection of saline without ANP. Addition of 0.25 or 2.5 μg ANP to the first injectate enhanced RBF by 21 and 35%, respectively (both P 〈 0.05), but did not modify the time sequence. Furthermore, addition of 0.25 μg ANP to the second and third injectate produced an almost similar change in RBF at the end of each injection (ΔRBF = 20 and 17%, respectively). In contrast, the addition of 2.5 μg ANP to the second and third injectate did not produce the same changes in RBF observed at the end of the first injection. The amplitude of the change in RBF was then similar to the increase in RBF induced by 1 mL saline without ANP. Mean arterial pressure (MAP) did not change significantly during repeated injections of saline alone or with addition of 0.25 μg ANP to the first injectate. However, MAP decreased significantly (by 5, 9 and 9 mmHg) after the injection of 3 × 0.25, 1 × 2.5 or 3 × 2.5 μg ANP, respectively.4. Sodium excretion was rapidly increased from 2.600±0.654 to 9.330±1.322 μmol/min after injection of 3 × 1 mL of 0.85% NaCl (P 〈 0.05). Thereafter, sodium excretion remained enhanced throughout the experiment, so that 70% of the sodium load injected was recovered at the end of the experiment. Atrial natriuretic peptide added to the injectates further elevated the maximal responses in diuresis and natriuresis induced by saline injections without ANP (P 〈 0.001). A maximal effect was observed after the addition of 2.5 μg ANP to the first saline solution. When the amount of sodium excreted was calculated by integrating the areas under the curve of the natriuretic responses, a relationship was established as a function of the amount of ANP added to the saline solutions. It was characterized by a threshold in the presence of 2.5 μg ANP added to the first injectate when the integration period was limited to 4 min 30 s and 14 min 30 s after starting the first injection of the varying test solutions. When the integration period was extended until the end of the experiment (2 h), the amount of sodium excreted in each group was further enhanced, especially after injection of 3 × 1 mL of 0.85% NaCl without ANP or with 1 × 0.25 and 3 × 0.25 μg ANP. Differences in sodium excretion between groups were attenuated (P 〈 0.054, ANOVA).5. In conclusion, our results demonstrate differential effects of synthetic ANP on renal vascular reactivity and excretory capacity. These effects were superimposed on changes induced by acute volumic stress. In particular, effects of saline injections on renal vascular compliance were amplified in the presence of ANP added in varying amounts to the injectates. This amplification was limited to 2.5 μg ANP.
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  • 9
    ISSN: 1617-4623
    Keywords: Autonomously replicating sequence ; Chloroplast DNA ; Replication origin ; Petunia hybrida ; Luglena gracilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Three distinct chloroplast (cp) DNA fragments from Petunia hybrida, which promote autonomous replication in yeast, were mapped on the chloroplast genome. Sequence analysis revealed that these fragments (called ARS A, B and C) have a high AT content, numerous short direct and inverted repeats and at least one yeast ARS consensus sequence 5′A/TTTTATPuTTTA/T, essential for yeast ARS activity. ARS A and B also showed the presence of (semi-)conserved sequences, present in all Chlamydomanas reinhardii cpDNA regions that promote autonomous replication in yeast (ARS sequences) or in C. reinhardii (ARC sequences). A 431 bp BamHI/EcoRI fragment, close to one of the inverted repeats and adjacent to the ARS B subfragment contains an AT-rich stretch of about 100 nucleotides that show extensive homology with an Euglena gracilis cpDNA fragment which is part of the replication origin region. This conserved region contains direct and inverted repeats, stem-and-loop structures can be folded and it contains an ARS consensus sequence. In the near vicinity a GC-rich block is present. All these features make this cpDNA region the best candidate for being the origin of replication of P. hybrida cpDNA.
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 378 (1995), S. 68-70 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Investigation of the genetics, gonads, genitalia or hormone level of transsexuals has not, so far, produced any results that explain their status1'2. In experimental animals, however, the same gonadal hormones that prenatally determine the morphology of the genitalia also influence the morphology ...
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