Antimicrobial prophylaxis in patients undergoing abdominal surgery.
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Abdomen↗
Biomedical subjects
K Christiansen
Publications and source records attributed to K Christiansen.
Influence of dry heat treatment and anticoagulant on coupling of fibrinogen and fibronectin to von Willebrand factor in normal plasma.
In plasma from healthy subjects a coupling was identified between von Willebrand factor (vWf), fibrinogen (fg), and fibronectin (fn) that was dependent of anticoagulants heparin, EDTA, and citrate. Binding was quantitated by ELISA methodologies, based on polyclonal antibodies directed against the proteins studied, in order to express the percentage of moles of fg or fn bound to moles vWf, C[fg/vWf] or C[fn/vWf] (mol/mol)%. The intra-assay coefficients of variation (CV%) for fg and fn bound to vWf were 10.6% and 7.4% (n = 10) respectively, and the inter-assay coefficients of variation were 24.4% and 22.2% (n = 10). The largest degree of coupling was found in heat-treated lyophilized heparin plasma, where C[fg/vWf] and C[fn/vWf] were 12.9 +/- 1.4 (mol/mol)% and 2.4 +/- 0.1 (mol/mol)% (mean +/- SD). Binding was further qualitatively demonstrated through experiments using gel filtration chromatography and agarose gel electrophoresis followed by immunoblotting. In all instances coupling of vWf with fg was higher than with fn. Lyophilisates of normal plasma that were subjected to dry heating (60 degrees C in 72 h) showed considerably increased coupling. Previous investigators, studying reconstituted factor VIII concentrates by means of gel filtration, pointed out that an association between vWf, fg and fn was present in such therapeutic material. This investigation signifies that a coupling between these proteins may be present even in the source plasma, and that 'dry heating' increases binding. Implications of these results are discussed.
Anticoagulants↗
New technique for uncoupling the cleavage and religation reactions of eukaryotic topoisomerase I. The mode of action of camptothecin at a specific recognition site.
A new technique for uncoupling the cleavage and religation half-reactions of topoisomerase I at a specific site has been developed. The technique takes advantage of a suicidal DNA substrate to attain enzyme-mediated cleavage without concomitant religation. Efficient religation can be achieved, subsequently, by addition of an oligonucleotide capable of hybridising to the non-cleaved strand of the suicide DNA substrate. The technique was used to study the effect of different compounds on the half-reactions of topoisomerase I. It was shown that topoisomerase I-mediated cleavage was inhibited by NaCl concentrations higher than 200 mM, while the religation reaction seemed unaffected by concentrations as high as 3 M-NaCl. The divalent cations Mg2+, Ca2+ and Mn2+ were found to enhance the cleavage but not the religation reaction of topoisomerase I, whereas Cu2+ and Zn2+ inhibited both reactions. Furthermore, the effect of the anti-neoplastic agent, camptothecin, on the half-reactions of topoisomerase I was investigated. It was found that the drug did not affect the cleavage reaction of topoisomerase I at the studied site, while the religation reaction of the enzyme was inhibited. Camptothecin was found to stabilise the enzyme-DNA cleavage complex even when the drug was added after complex formation.
Antineoplastic Agents↗
Studies of the topoisomerase II-mediated cleavage and religation reactions by use of a suicidal double-stranded DNA substrate.
The cleavage and religation reactions of eukaryotic topoisomerase II were studied by use of a 5'-recessed DNA substrate containing a strong recognition sequence for the enzyme. Cleavage of the DNA substrate was suicidal, that is the enzyme was unable to religate the cleaved DNA due to a release of DNA 5' to the cleavage position. With this substrate cleavage products accumulated with time in the absence of protein-denaturing agents, and the cleavage reaction was not reversible with salt. The suicide cleavage complexes contained a kinetically competent topoisomerase II enzyme as determined by the enzyme's ability to perform intermolecular ligation of the cleaved DNA to a free 3'-hydroxyl end on another DNA strand. The efficiency of the religation reaction depended on the ability of the religation substrate to base pair to the DNA in the cleaved enzyme-DNA complex. Higher levels of religation were obtained with dinucleotides than with long DNA substrates. Mononucleotides also were efficiently religated, indicating an ability of the enzyme to mediate religation without making contacts to a long stretch of nucleotides 5' to the cleavage position.
Animals↗
Incentive spirometry versus routine chest physiotherapy for prevention of pulmonary complications after abdominal surgery.
We entered 876 patients into a clinical trial aimed at preventing pulmonary complications after abdominal surgery. Patients either received conventional chest physiotherapy or were encouraged to perform maximal inspiratory manoeuvres for 5 min during each hour while awake, using an incentive spirometer. The incidence of pulmonary complications did not differ significantly between the groups: incentive spirometry 68 of 431 (15.8%, 95% CI 14.0-17.6%), and chest physiotherapy 68 of 445 (15.3%, CI 13.6-17.0%). Nor was there a difference between the groups in the incidence of positive clinical signs, pyrexia, abnormal chest radiographs, pathogens in sputum, respiratory failure (PO2 less than 60 mm Hg), or length of stay in hospital. We conclude that prophylactic incentive spirometry and chest physiotherapy are of equivalent clinical efficacy in the general management of patients undergoing abdominal surgery.
Abdomen↗
A model for the quaternary structure of human placental insulin receptor deduced from electron microscopy.
Electrophoretically pure and functionally intact human placental insulin receptor was studied by electron microscopy with negative-staining techniques. The quaternary structure of the detergent-solubilized receptor was determined. The receptor had the shape of a letter T approximately 24 nm in height and 18 nm in width with a thickness of the stem and the crossbar of 3-4 nm. No consistent change in ultrastructure of the receptor could be detected after the addition of insulin alone or insulin and Mn2+/Mg2+/ATP. After partial reduction of the alpha 2 beta 2 heterotetrameric receptor into alpha beta heterodimers, the electron micrographs showed a clear reduction in average size of the molecule with disappearance of the T profiles characteristic of the alpha 2 beta 2 heterotetramers. By incubation of the heterodimers in a phosphorylation medium containing insulin, a reassociation to molecules with molecular weights of the alpha 2 beta 2 heterotetramer took place judged from SDS/PAGE. Electron microscopy showed that the molecule formed larger aggregates, and only a few solitary T-shaped copies were seen.
Chromatography, Affinity↗
A comparison of the roles of cefamandole and ceftriaxone in abdominal surgery.
In a prospective, randomized study, we compared the ability of ceftriaxone sodium (serum half-life, 8.0 hours) and cefamandole naftate and sodium carbonate (serum half-life, 0.8 hours) to prevent wound infection in 1238 patients undergoing abdominal surgery. Prophylaxis consisted of single-dose therapy at the time of induction of anesthesia, and treatment regimens contained ceftriaxone sodium, 1 g/d intravenously, or cefamandole naftate and sodium carbonate, 1 g intravenously every 6 hours. Except for low-risk biliary procedures, cephalosporin therapy was accompanied by the administration of metronidazole. No significant difference was noted in the incidence of wound infection, ie, 5.6% for the ceftriaxone group (95% confidence interval, 3.8% to 7.4%) and 6.9% for the cefamandole group (95% confidence interval, 4.9% to 8.9%). Single-dose prophylaxis with 1 g of cefamandole naftate and sodium carbonate was relatively inexpensive and provided a cost savings of 64%. When treatment was required, a 23% cost savings was associated with the use of a once-daily dose of 1 g of ceftriaxone sodium.
Abdomen↗
Drug Stimulated DNA Cleavage Mediated by Cauliflower Topoisomerase II.
We have investigated cauliflower (Brassica oleracea) topoisomerase II with respect to its interaction with DNA and demonstrate that the enzyme shares the characteristics of topoisomerase II purified from a variety of phylogenetically remote organisms. In the presence of the 2-nitroimidazole Ro 15-0216, cauliflower topoisomerase II-mediated DNA cleavage is extensively stimulated (approximately 20-fold) only at a site recognized as a major cleavage site for the enzyme in the absence of drug. The conservation of the enzyme's DNA specificity in the presence of Ro 15-0216 is in contrast to the effect exerted by traditional topoisomerase II inhibitors, which cause enzyme-mediated cleavage to take place at a multiple number of DNA sites. Ro 15-0216 may therefore prove useful as a tool in the elucidation of the enzyme's DNA interaction sites and its involvement in nucleic acid metabolism in plant cells.
Journal Article↗
Risk of HTLV-1 transmission in renal transplantation among aborigines.
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HTLV-I Antibodies↗
Stimulation of topoisomerase II mediated DNA cleavage at specific sequence elements by the 2-nitroimidazole Ro 15-0216.
The effect of the 2-nitroimidazole Ro 15-0216 upon the interaction between purified topoisomerase II and its DNA substrate was investigated. The cleavage reaction in the presence of this DNA-nonintercalative drug took place with the hallmarks of a regular topoisomerase II mediated cleavage reaction, including covalent linkage of the enzyme to the cleaved DNA. In the presence of Ro 15-0216, topoisomerase II mediated cleavage was extensively stimulated at major cleavage sites of which only one existed in the 4363 base pair pBR322 molecule. The sites stimulated by Ro 15-0216 shared a pronounced sequence homology, indicating that a specific nucleotide sequence is crucial for the action of this drug. The effect of Ro 15-0216 thus differs from that of the clinically important topoisomerase II targeted agents such as mAMSA, VM26, and VP16, which enhance enzyme-mediated cleavage at a multiple number of sites. In contrast to the previous described drugs, Ro 15-0216 did not exert any inhibitory effect on the enzyme's catalytic activity. This observation might be ascribed to the low stability of the cleavage complexes formed in the presence of Ro 15-0216 as compared to the stability of the ones formed in the presence of traditional topoisomerase II targeted drugs.
Acetanilides↗
Minimal DNA requirement for topoisomerase II-mediated cleavage in vitro.
The minimal DNA requirement for topoisomerase II-mediated DNA cleavage in vitro was determined by analyzing the interaction of the enzyme with sets of DNA substrates varying successively by single bases at the 5'- or 3'-end of either strand. A 16-base pair double-stranded region was established as the minimal duplex region required for topoisomerase II cleavage activity. The region was located symmetrically around the 4-base staggered cleavage site. Topoisomerase II-mediated cleavage within the 16-base pair core duplex, however, required single-stranded regions flanking the duplex to either the 5'- or 3'-sides, or an extension at both ends of the duplex with 1 or more base pairs.
Animals↗
Minimal DNA duplex requirements for topoisomerase I-mediated cleavage in vitro.
The minimal DNA duplex requirements for topoisomerase I-mediated cleavage at a specific binding sequence were determined by analyzing the interaction of the enzyme with sets of DNA substrates varying successively by single nucleotides at the 5'- or 3' end of either strand. Topoisomerase I cleavage experiments showed a minimal region of nine nucleotides on the scissile strand and five nucleotides on the noncleaved strand. On the scissile strand, seven of the nine nucleotides were situated upstream to the cleavage site, while all five nucleotides required on the non-cleaved strand were located to this side. The results suggested that topoisomerase I bound tightly to this region, stabilizing the DNA duplex extensively. On minimal substrates which were partially single-stranded downstream to the cleavage site, cleavage was suicidal, that is, the enzyme was able to cleave the substrates, but unable to perform the final religation.
Base Sequence↗
Herpes simplex virus interstitial nephritis in a renal allograft.
We report a 35-year-old woman who developed herpes simplex virus (HSV) type 1 interstitial nephritis following a cadaveric renal transplant. Transplant function was poor and a transplant nephrectomy was performed 23 days post-transplant. Histological changes characteristic of herpes virus infection were seen on the renal biopsy with positive immunoperoxidase staining for HSV. HSV 1 was cultured from the transplant nephrectomy specimen.
Adult↗
[Sex hormone level and body shape of the !Kung San. A contribution to explaining pedomorphic stature of San populations].
In order to test the hypothesis that oestrogens as well as androgens modify the body shape resp. the paedomorphous habitus of !Kung San circulating levels of sex hormones (testosterone, 5 alpha-dihydrotestosterone, and oestradiol in the serum as well as free testosterone in the saliva) of 114 healthy !Kung San men from the Northern Kalahari of Namibia were quantitatively determined by means of the radioimmunoassay method. The probands were described by 50 body measurements and morphological characters like gynaecomastia. The results show that sex hormone concentrations and body shape are significantly correlated in !Kung San men as it has been previously demonstrated for non-African samples. This does not only refer to the expression of sexual dimorphism but also to the special aspect of paedomorphism. The hypothesis of Marrett, Davies and Tobias, however, that the paedomorphous type of the San is due to "over-oestrogenization" could not be confirmed. Rather, the comparatively low testosterone level of the !Kung San men seems to be of significance.
Adult↗
Double-stranded DNA cleavage/religation reaction of eukaryotic topoisomerase II: evidence for a nicked DNA intermediate.
The DNA cleavage reaction of eukaryotic topoisomerase II produces nicked DNA along with linear nucleic acid products. Therefore, relationships between the enzyme's DNA nicking and double-stranded cleavage reactions were determined. This was accomplished by altering the pH at which assays were performed. At pH 5.0 Drosophila melanogaster topoisomerase II generated predominantly (greater than 90%) single-stranded breaks in duplex DNA. With increasing pH, less single-stranded and more double-stranded cleavage was observed, regardless of the buffer or the divalent cation employed. As has been shown for double-stranded DNA cleavage, topoisomerase II was covalently bound to nicked DNA products, and enzyme-mediated single-stranded cleavage was salt reversible. Moreover, sites of single-stranded DNA breaks were identical with those mapped for double-stranded breaks. To further characterize the enzyme's cleavage mechanism, electron microscopy studies were performed. These experiments revealed that separate polypeptide chains were complexed with both ends of linear DNA molecules generated during cleavage reactions. Finally, by use of a novel religation assay [Osheroff, N., & Zechiedrich, E. L. (1987) Biochemistry 26, 4303-4309], it was shown that nicked DNA is an obligatory kinetic intermediate in the topoisomerase II mediated reunion of double-stranded breaks. Under the conditions employed, the apparent first-order rate constant for the religation of the first break was approximately 6-fold faster than that for the religation of the second break. The above results indicate that topoisomerase II carries out double-stranded DNA cleavage/religation by making two sequential single-stranded breaks in the nucleic acid backbone, each of which is mediated by a separate subunit of the homodimeric enzyme.
Animals↗
Strand specificity of the topoisomerase II mediated double-stranded DNA cleavage reaction.
The strand specificity of topoisomerase II mediated DNA cleavage was analyzed at the nucleotide level by characterizing the enzyme's interaction with a strong DNA recognition site. This site was isolated from the promoter region of the extrachromosomal rRNA genes of Tetrahymena thermophila and was recognized by type II topoisomerases from a variety of phylogenetically diverse eukaryotic organisms, including Drosophila, Tetrahymena, and calf thymus. When incubated with this site, topoisomerase II was found to introduce single-stranded breaks (i.e., nicks) in addition to double-stranded breaks in the nucleic acid backbone. Although the nucleotide position of cleavage on both the noncoding and coding strands of the rDNA remained unchanged, the relative ratios of single- and double-stranded DNA breaks could be varied by altering reaction conditions. Under all conditions which promoted topoisomerase II mediated DNA nicking, the enzyme displayed a 3-10-fold specificity for cleavage at the noncoding strand of its recognition site. To determine whether this specificity of topoisomerase II was due to a faster forward rate of cleavage of the noncoding strand or a slower rate of its religation, a DNA religation assay was performed. Results indicated that both the noncoding and coding strands were religated by the enzyme at approximately the same rate. Therefore, the DNA strand preference of topoisomerase II appears to be embodied in the enzyme's forward cleavage reaction.
Animals↗
Use of peri-operative antibiotics in abdominal surgery: a criterion audit.
OBJECTIVE: To evaluate the peri-operative use of parenteral antibiotics in 100 patients undergoing abdominal surgery. METHOD: Prospective criterion audit. RESULTS: There is a need for the close monitoring of antibiotic usage within hospitals, because 39% of the patients received inappropriate antibiotic therapy.
Abdomen↗
Rat hepatic microsomal cytochrome b5. A simple large-scale purification procedure and antibody production by antigen-containing liposomes.
Cytochrome b5 from rat liver microsomes (microsomal fractions) was purified in its native form. The procedure described has great capacity, is fast, and the final product is pure as judged from SDS/polyacrylamide-gel electrophoresis. Antibodies to cytochrome b5 are obtained after administration of the antigen inserted into small unilamellar lipid vesicles.
Animals↗