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Biomedical subjects

C Braun

Publications and source records attributed to C Braun.

At least 127 records · Page 7Linked to original sources
PubMed1992

Staged major limb replantation: a concept to minimize the risk in replantation of the lower extremity.

The replantation of large limb segments presents two major problems: first, a general danger to survival because of major accompanying injuries and additional ischemia-reperfusion injury; second, local soft-tissue damage at the amputation site. Successful replantation can be compromised by infection, vessel thrombosis, and disturbed bone healing. Possible risk reduction may be accomplished by the concept of a two-staged replantation. A brief primary emergency procedure involving bone resection, osteosynthesis, and revascularization (with the goal of limb survival) is followed by a second procedure within 72 hr after trauma, for final debridement, completing the osteosynthesis, nerve and tendon suturing, and soft-tissue coverage by free flaps. The advantages of the double procedure are demonstrated in 27 patients by comparison of two treatment groups. Group I comprised 15 patients with definitive primary care. In Group 2 (n = 12), the two-stage operation was performed. The second group showed a shorter duration of overall treatment, reduction of blood loss, and fewer infections.

Adult↗
PubMed1992

The structural genes of the nitric oxide reductase complex from Pseudomonas stutzeri are part of a 30-kilobase gene cluster for denitrification.

A gene cluster of 30 kilobases required for denitrification in Pseudomonas stutzeri ZoBell was identified and mapped. It harbors genes necessary for the respiratory reduction of nitrite (nir genes), nitric oxide (nor genes), and nitrous oxide (nos genes). Fifteen genes, 13 of which are transcribed in the same direction, have been located on a 56-kb BamHI fragment. They are arranged in three subclusters in the order nos-nir-nor.

Base Sequence↗
PubMed1992

[A simple method for repositioning metatarsal fractures].

Because of small direct contact to the fracture fragments reduction of metatarsal fractures can be achieved only indirectly by applying traction to the toes. In this article a method for simple direct manipulation of the distal main fragment of metatarsal fractures is described: A K-wire is drilled in dorsi plantar direction across the head of the fractured metatarsal and mounted on a traction bow. In this manner the distal fracture fragment can be moved in all directions and placed exactly onto the proximal fragment. All 8 patients with multiple metatarsal fractures could be treated by closed reduction and percutaneous pinning. The described method allows simple and precise reduction of metatarsal fractures, reduced x-ray exposure of the surgeon's hand by short operation times, and manipulation for fracture reduction outside the x-ray beam.

Bone Wires↗
PubMed1992

[Determination of the spread of epidural anesthesia. A comparison between pin-prick and a new method using a metallic roller].

A new method (metal roller) for testing the spread of analgesia in regional anesthesia is introduced. The possible advantages of testing with a metal roller (cold sensation) in comparison to the pinprick method are investigated and discussed to determine whether loss of cold-sensation is comparable to loss of pinprick-sensation and thus reliable in clinical practice. METHOD AND MATERIAL. Spread of analgesia was tested with both the metallic roller and the conventional pinprick method in 40 patients (20 epidural and 20 spinal blocks), and pain perception or cold perception were compared. RESULTS. In epidural as well as in spinal anesthesia, similar levels of loss of pain perception and cold perception were found. DISCUSSION. Testing the spread of analgesia after nerve bock by the pinprick method is sometimes unpleasant for the patient. The metal roller is not unpleasant, and the possible danger of contamination or pinprick pain is virtually impossible because physical integrity is preserved and the feeling of "cold" is not harmful.

Anesthesia, Epidural↗
PubMed1992

[Thumb reconstruction with cryopreserved autogenous thumb skeleton and microneurovascular flap].

This paper describes a procedure for thumb reconstruction using autogenous cryo-conserved bone from the thumb itself. In a case of severe explosion injury, the thumb and index finger were amputated at the carpometacarpal joint level and the remaining fingers at the distal interphalangeal joint level. Severe soft tissue damage and lesion of both the superficial and deep palmar arterial arches rendered customary surgical procedures for thumb reconstruction impossible. The cryo-conserved bone was replanted following soft tissue healing and then covered with a free radial forearm flap. This procedure resulted in a stable and painfree thumb and provided satisfactory grip.

Adult↗
PubMed1991

Marker exchange of the structural genes for nitric oxide reductase blocks the denitrification pathway of Pseudomonas stutzeri at nitric oxide.

Bacterial denitrification reverses nitrogen fixation in the global N-cycle by transforming nitrate or nitrite to dinitrogen. Both nitrite and nitric oxide (NO) are considered as the chemical species within the denitrification pathway, that precede nitrous oxide (N2O), the first recognized intermediate with N,N-bonds antecedent to N2. Molecular cloning of the structural genes for NO reductase from Pseudomonas stutzeri has allowed us to generate the first mutants defective in NO utilization (Nor- phenotype) by marker exchange of the norCB genes with a gene cassette for gentamicin resistance. Nitric oxide reductase was found to be an indispensable component for denitrification; its loss constituted a conditionally lethal mutation. NO as the sole product accumulated from nitrite by mutant cells induced for nitrite respiration (denitrification). The Nor- mutant lost the capability to reduce NO and did not grow anymore anaerobically on nitrate. A Nir-Nor- double mutation, that inactivated also the respiratory nitrite reductase cytochrome cd1 rendered the bacterium again viable under anaerobiosis. Our observations provide evidence for a denitrification pathway in vivo of NO2(-)----NO----N2O, and N,N-bond formation catalyzed by NO reductase and not by cytochrome cd1.

Amino Acid Sequence↗
PubMed1991

Reassessment of the catalytic mechanism of glycogen debranching enzyme.

The amylo-1,6-glucosidase catalytic activity of glycogen debranching enzyme allows it to hydrolyze alpha-D-glucosyl fluoride, in the absence or presence of glycogen or oligosaccharides, releasing equal amounts of fluoride and glucose at rates comparable to those seen with the natural substrates. 2-Deoxy-2-fluoro-alpha-D-glucosyl fluoride is found to be a poor substrate, rather than the covalent inhibitor that would be expected for a glucosidase which catalyzes hydrolysis of the glycosidic linkage with retention of anomeric configuration. In fact, analysis of the glucosidase reaction by NMR reveals that the debranching enzyme hydrolyzes the glycosidic linkage with inversion of configuration, releasing beta-D-glucose from both alpha-glucosyl fluoride and its natural substrate, the phosphorylase limit dextrin. In contrast, its transferase activity necessarily proceeds with retention of configuration. As has been seen with other "inverting" glycosidases, the debranching enzyme releases beta-D-glucose from beta-D-glucosyl fluoride in the presence of oligosaccharides such as maltohexaose and cyclomaltoheptaose but, unlike the others, not in their absence. An intermediate glucosyl-alpha-(1,6)-cyclomaltoheptaose has been detected by NMR analysis. In the presence of a water-soluble carbodiimide, a single mole of glycine ethyl ester is incorporated into each mole of the debranching enzyme, resulting in its inactivation when measured by the combined assay for both transferase and glucosidase activities. Measurement of the latter two activities independently indicates that it is the transferase activity which is inactivated, while the glucosidase activity, measured with alpha-D-glucosyl fluoride as substrate, is unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Anthralin derivatives--inhibition of 5-lipoxygenase--antipsoriatic efficacy.

Inhibition of 5-lipoxygenase by anthralin (1) and 41 derivatives is determined: the acids 38 and 39, the lactones 40-42 and 9-anthrone (8) are the most potent inhibitors, the lactone 41 reaching the efficacy of nordihydroguaiaretic acid (NDGA). The results were correlated with the hydrophilic/lipophilic balance of the test compounds and their clinical efficacy as far as known. There is no correlation between the "minimum structure" of Krebs and Schaltegger concerning antipsoriatic activity and the inhibitory effects against 5-lipoxygenase.

Animals↗
PubMed1991

Close linkage in Pseudomonas stutzeri of the structural genes for respiratory nitrite reductase and nitrous oxide reductase, and other essential genes for denitrification.

The structural gene, nirS, for the respiratory nitrite reductase (cytochrome cd1) from Pseudomonas stutzeri was identified by (i) sequencing of the N-terminus of the purified protein and partial sequencing of the cloned gene, (ii) immunoscreening of clones from a lambda gt11 expression library, (iii) mapping of the transposon Tn5 insertion site in the nirS mutant strain MK202, and (iv) complementation of strain MK202 with a plasmid carrying the insert from an immunopositive lambda clone. A mutation causing overproduction of cytochrome c552 mapped on the same 8.6 kb EcoRI fragment within 1.7 kb of the mutation affecting nirS. Two mutations affecting nirD, which cause the synthesis of an inactive cytochrome cd1 lacking heme d1, mapped 1.1 kb apart within a 10.5 kb EcoRI fragment contiguous with the fragment carrying nirS. Nir- mutants of another type that had low level synthesis of cytochrome cd1, had Tn5 insertions within an 11 kb EcoRI fragment unlinked to the nirS+ and nirD+ fragments. Cosmid mapping provided evidence that nirS and nirD, and the previously identified gene cluster for nitrous oxide respiration are closely linked. The nirS gene and the structural gene for nitrous oxide reductase, nosZ, are transcribed in the same direction and are separated by approximately 14 kb. Several genes for copper processing are located within the intervening region.

Amino Acid Sequence↗
PubMed1991

Quenched flow analysis of exocytosis in Paramecium cells: time course, changes in membrane structure, and calcium requirements revealed after rapid mixing and rapid freezing of intact cells.

Synchronous exocytosis in Paramecium cells was analyzed on a subsecond time scale. For this purpose we developed a quenched flow device for rapid mixing and rapid freezing of cells without impairment (time resolution in the millisecond range, dead time approximately 30 ms). Cells frozen at defined times after stimulation with the noncytotoxic secretagogue aminoethyldextran were processed by freeze substitution for electron microscopic analysis. With ultrathin sections the time required for complete extrusion of secretory contents was determined to be less than 80 ms. Using freeze-fracture replicas the time required for resealing of the fused membranes was found to be less than 350 ms. During membrane fusion (visible 30 ms after stimulation) specific intramembranous particles in the cell membrane at the attachment sites of secretory organelles ("fusion rosette") disappear, possibly by dissociation of formerly oligomeric proteins. This hitherto unknown type of rapid change in membrane architecture may reflect molecular changes in protein-protein or protein-lipid interactions, presumably crucial for membrane fusion. By a modification of the quenched flow procedure extracellular [Ca++] during stimulation was adjusted to less than or equal to 3 x 10(-8) M, i.e., below intracellular [Ca++]. Only extrusion of the secretory contents, but not membrane fusion, was inhibited. Thus it was possible to separate both secretory events (membrane fusion from contents extrusion) and to discriminate their Ca++ requirements. We conclude that no Ca++ influx is necessary for induction of membrane fusion.

Animals↗
PubMed1991

Unusual sequence organization in CenB, an inverting endoglucanase from Cellulomonas fimi.

The nucleotide sequence of the cenB gene was determined and used to deduce the amino acid sequence of endoglucanase B (CenB) of Cellulomonas fimi. CenB comprises 1,012 amino acids and has a molecular weight of 105,905. The polypeptide is divided by so-called linker sequences rich in proline and hydroxyamino acids into five domains: a catalytic domain of 607 amino acids at the N terminus, followed by three repeats of 98 amino acids each which are greater than 60% identical, and a C-terminal domain of 101 amino acids which is 50% identical to the cellulose-binding domains of C. fimi cellulases Cex and CenA. A deletion mutant of the cenB gene encodes a polypeptide lacking the C-terminal 333 amino acids of CenB. The truncated polypeptide is catalytically active and, like intact CenB, binds to cellulose, suggesting that CenB has a second cellulose-binding site. The sequence of amino acids 1 to 461 of CenB is 35% identical, with a further 15% similarity, to that of a cellulase from avocado, which places CenB in cellulase family E. CenB releases mostly cellobiose and cellotetraose from cellohexaose. Like CenA, CenB hydrolyzes the beta-1,4-glucosidic bond with inversion of the anomeric configuration. The pH optimum for CenB is 8.5, and that for CenA is 7.5.

Amino Acid Sequence↗
PubMed1991

[Reconstruction of large foot sole areas with microsurgical tissue transfers].

In 14 patients with microsurgically reconstructed areas of the sole videografic gait analysis was performed. The best results are reached after reconstruction of the forefoot. Loss of more than two thirds of the sole leads to functional impairment. For all reconstructed areas and all types of flaps gait is improved significantly by shoe adaptation: elevation of the shoe under the reconstructed part of the sole directs the main load to the opposite side of the foot and by this relieves the reconstructed area. Even bone corrections can reduce load on a circumscribed area.

Foot↗
PubMed1991

[Correlation between respiratory tract symptoms in young children and NO2 concentration of outside air].

The aim of a one year study was to ascertain whether air pollution measured as NO2-concentration has an measurable influence on the health of infants in Switzerland. Measurements of NO2-concentration were carried out by means of passive collectors in ambient air, living room and at the child itself. The results of 1225 children printed to a significant coherence between respiratory symptoms per day and child and the NO2 load of ambient air as an guide pollutant. Even in consideration of other childish, familiar and environmental factors the coherence remains. Although no causal relation thereby proved this factor supports the observation of parents and physicians that children more often fall ill of respiratory diseases in polluted air being in accordance with similar investigations abroad.

Air Pollutants↗
PubMed1991

Dithranol, glucose-6-phosphate dehydrogenase inhibition and active oxygen species.

Inhibition of glucose-6-phosphate dehydrogenase (G6-PDH) by dithranol (anthralin, CAS 480-22-8) has been studied in the presence of catalase, superoxide dismutase (SOD) and various scavengers of active oxygen species. Most scavengers were found to be either inhibitors of G6-PDH by themselves or simply without effect. The combined addition of catalase and SOD as well as the heat-denatured enzymes and the oxygen radical scavengers alpha-tocopherol and salicylic acid markedly reduced the inhibitory effect of dithranol. The direct exposure of G6-PDH to active oxygen species led to different results. When liberated from a water-soluble naphthalene endoperoxide, singlet oxygen was without effect whereas photosensitization with methylene blue resulted in a total loss of enzyme activity. Experiments under anaerobic conditions revealed that this inhibition was accomplished by the triplet state of the sensitizer. Superoxide anion radical was highly effective at concentrations corresponding to the amount of that produced by a 10 mumol/l dithranol solution. In contrast, hydroxyl, alkylperoxyl and alkoxyl radicals were all less efficient. H2O2 and alkylhydroperoxides did not alter the enzyme activity. The results suggest that .O2- is the potent species towards G6-PDH, if dithranol acts through formation of active oxygen species.

Anaerobiosis↗
PubMed1991

[Rupture of the tendon of the m. flexor pollicis longus--a rare complication after surgery on the scaphoid bone].

Tendon ruptures in the hand without previous direct trauma are rare. Two cases are reported on with attrition of the flexor pollicis longus tendon. The first tendon rupture was along a dislocated cortico-cancellous bone graft following a Matti-Russe procedure; the second was by attrition over the screw of an AO-plate following internal fixation in scaphoid nonunion. Immediate tendon repair by interposition of a short tendon graft or by transposition of the superficialis flexor tendon of the ring finger is the treatment of choice. Further tendon ruptures can arise if surgical intervention is delayed.

Adult↗
PubMed1991

[Experiences with continuous nerve block of the wrist].

Continuous nerve blocks are effective analgesics for physiotherapy following operative procedures on gliding tissues. In the upper extremity, continuous axillary blocks are regularly used, leading to weak muscular action and even paralysis, although active muscle action is wanted. With continuous wrist blocks, extrinsic motor function of the hand remains undisturbed. Placement of a polyethylene catheter near the nerves with instillation of a local anesthetic (carbostesine 0.5, 3-4 ml per nerve) provides complete anesthesia of the hand without loss of extrinsic motor function. After 124 nerve blocks in 60 patients, no complications (infections, nerve irritations or lesions) have been observed. Continuous wrist blocks are indicated for postoperative treatment after tenolysis, joint mobilisation or arthrolysis, open reduction and internal fixation and in certain cases of chronic pain care.

Analgesia↗