[Perioperative local instillation of ropivacaine for postoperative pain relief after surgery on extremities]

INTRODUCTION

The relief of postoperative pain remains one of the most important goals for adequate surgical patient care.

METHODS

Prospective, randomised, double-blinded study, including 118 patients (67 M;/ 51 F; median age 43 years, min. 18, max. 74). Two groups were formed. In the verum group a wound instillation with ropivacaine was performed, in the control group not. Intensity of pain, demand for analgesics and satisfaction of the patient were evaluated postoperatively. In 10 patients ropivacaine plasma levels were measured.

RESULTS

Significant postoperative pain relief and a decrease in analgesic consumption were found on instillation of ropivacaine. Compared to the control group, patients receiving ropivacaine were significantly more satisfied with the postoperative pain management. Potential toxic plasma levels were not found.

CONCLUSION

By the presented method, the surgeon actively contributes to a significant reduction in postoperative pain and analgesic consumption. Furthermore, the patient's benefit is reflected by higher satisfaction with the pain management. Complications due to toxic plasma levels are not seen.

Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament and the lateral collateral ligament using hamstrings and absorbable screws

Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament (PCL) and the lateral collateral ligament (LCL) using hamstring tendon grafts is described. The femoral tunnel is drilled through an incision over the medial femoral condyle and the tibial tunnel through the same skin incision used for harvesting the tendon graft. PCL reconstruction is performed using a 4-strand hamstring tendon graft and absorbable screw fixation. The tendon of the semitendinosus muscle of the uninvolved knee is used as a lateral loop for LCL reconstruction. After pulling the transplant through the fibular head, femoral fixation of the loop is made with an absorbable screw.

[Crossed screw osteosynthesis of proximal humerus fractures]

Between March 1997 and October 1999 thirty-one patients with displaced proximal humeral fractures were treated with crossed screw osteosynthesis. Insertion of the screws was realized by using a deltoideo-pectoral approach placing the screws anteriorly and posteriorly in a crossed manner from the distal fragment into the humeral head. Additionally, in all two-part-fractures a tension band was applied. In all three-part-fractures, the greater tuberosity was reattached by additional screws. In 21 patients (14 female, 7 male, median age 62 years, 18-86) a clinical and radiological follow-up (median 18 months, 10-29) was obtained. Fractures were classified as two-part-fractures in 10 patients and as three-part-fractures in 11 patients. According to the Constant-Score, "excellent" and "good" results were achieved in 15 patients, "moderate" results were found in 3 patients. However, in 3 patients results were only "poor" (1 two-part-, 2 three-part-fractures). The complication rate was 29% (premature hardware removal due to head perforation in 3 cases; humeral head necrosis necessitating prosthetic replacement in 2 patients; secondary displacement in 1 case). Crossed screw osteosynthesis represents an justified alternative in the surgical treatment of displaced proximal humeral fractures permitting early functional therapy.

[Fracture of the acromion. Diagnosis--treatment strategy--outcome]

The case of an 22-year-old man is presented, who sustained a dislocated fracture of the left acromion process and a not dislocated fracture of the left scapular body with a large subcutaneous décollement as well as a dammage of nervus axillaris occurring during a traffic accident. After resuming diagnostics by means of CT, a tension banding of the ventral part of the acromion and a plate osteosynthesis of the dorsal part was performed. 7 weeks after injury neurolysis of nervus axillaris has been done. 4 months after accident the patient shows a satisfying functional result in the Constant score. Diagnostic, treatment and functional results after operative treatment of dislocated fractures of the acromion are shown and discussed.

The fibrin intermediate, its place in the fibrinogen-fibrin transformation

Our preceding study indicated that, in course of coagulation of human fibrinogen by thrombin, substantial production of the fibrin intermediate (alpha-profibrin) lacking only one fibrinopeptide A (FPA) precedes the formation of alpha-fibrin monomer lacking both FPAs. The plateau concentration of alpha-profibrin (20% of initial fibrinogen) appearing in reactions indicated, however, that the second FPA is released four times faster than the first. The study reported here confirms those findings, and provides new insight into the significance of differing rate constants for the production of alpha-profibrin and its conversion to alpha-fibrin. The intermediate could be isolated in a distinct electrophoretic band by electrophoresing partial thrombin digests at high concentrations. Its identity was verified by digesting it with CNBr and by demonstrating that its N-terminal domain, the NDSK fragment, both lacks an FPA and contains an FPA, unlike the NDSKs of the bands from fibrin which contained no FPA or the fibrinogen band that lacked no FPA. The single step isolation also enabled us to confirm the 15-20% plateau level of alpha-profibrin in course of thrombin reactions, well below the 37% maximum that would be expected if release of the first and second FPA proceeded independently with no difference in rate. The 37% maximum is observed in reactions with atroxin, and it is suggested that the abundant production of alpha-profibrin underlies the therapeutic utility of atroxin as a defibrinating agent. Gel chromatography procedures were optimized for isolation of alpha-profibrin/fibrin mixtures free of fibrinogen, the final step of which involves literal use of agarose gel as a filter to remove fibrin aggregates from the fibrinogen free fractions (aggregates are left behind in gel filtration, rather than their moving ahead in gel chromatography). Unlike human fibrinogen, rabbit fibrinogen does not yield much alpha-profibrin in course of its conversion to fibrin, less than 10% as determined by electrophoresis and comparison with abundant production with atroxin. This low production of alpha-profibrin conformed with conclusions from our early studies on the generalized Shwartzman reaction in rabbits, and we now infer that the low production of alpha-profibrin and rapid conversion to fibrin by rabbit fibrinogen underlies the unparalleled susceptibility of these animals toward fibrinoid formation in the generalized Shwartzman reaction.

Transport of cytochrome c derivatives by the bacterial Tat protein translocation system

An experimental system developed previously for the heterologous expression of c-type cytochromes in Escherichia coli Q1has been adapted to monitor protein transfer across the bacteria's cytoplasmic membrane. Apocytochrome, lacking the haem cofactor and probably in an unfolded state, was readily transferred across the cytoplasmic membrane when fused to a Sec-specific signal peptide. Furthermore, cytochrome fused to a signal peptide regarded as specific for the twin arginine transport (Tat) system was translocated in an unfolded state by the Sec apparatus. After maturation and folding in the cytoplasm, Tat-mediated transfer of holocytochrome to the periplasm occurred. We conclude that, in addition to the nature of the specific signal peptide, the folding state of a particular protein also governs its acceptance by a given transport system.

Fracture-dislocations of the elbow joint--strategy for treatment and results

Between January 1993 and December 1996, 41 patients with fracture dislocation of the elbow joint were treated in our department. In 28 patients (median age 46 years, range 15-77 years; 16 male, 12 female), a clinical and radiological follow-up was obtained after median 34 months (range 12-59 months). In addition to the humero-ulnar dislocation, isolated fractures were present in 13 patients and combined fractures in 15 (all with involvement of the radial head). Primary neurological deficits were found in 7 and open fractures in 3 patients. In 7 patients, primary definitive surgical therapy was carried out by open reduction and internal fixation. A two-step surgical management (initial closed reduction and immobilization, 5 patients with external fixator, 7 with plaster; secondary open surgical procedure) was performed in 12 and conservative treatment in 9 patients. According to the Leipzig Elbow Score, taking subjective, clinical and radiological criteria into consideration, 4 patients achieved 'excellent' and 5 patients a 'good' result. Ten patients were scored 'moderate' and 9 'poor'. The rate of secondary complications necessitating revision was 36%. Poor results were primarily caused by extensive initial soft-tissue damage, delayed definitive surgical therapy, and ectopic heterotopic ossification. In contrast, fracture localization and degree of arthrosis were not of significant importance for the final outcome. In fracture dislocations, the goal is a primary definitive surgical treatment aiming for early postoperative physiotherapy.

Biomaterial engineered electrodes for bioelectronics

A series of single-cysteine-containing cytochrome c, Cyt c, heme proteins including the wild-type Cyt c (from Saccharomyces cerevisiae) and the mutants (V33C, Q21C, R18C, G1C, K9C and K4C) exhibit direct electrical contact with Au-electrodes upon covalent attachment to a maleimide monolayer associated with the electrode. With the G1C-Cyt c mutant, which includes the cysteine residue in the polypeptide chain at position 1, the potential-induced switchable control of the interfacial electron transfer was observed. This heme protein includes a positively charged protein periphery that surrounds the attachment site and faces the electrode surface. Biasing of the electrode at a negative potential (-0.3 V vs. SCE) attracts the reduced Fe(II)-Cyt c heme protein to the electrode surface. Upon the application of a double-potential-step chronoamperometric signal onto the electrode, where the electrode potential is switched to +0.3 V and back to -0.3 V, the kinetics of the transient cathodic current, corresponding to the re-reduction of the Fe(III)-Cyt c, is controlled by the time interval between the oxidative and reductive potential steps. While a short time interval results in a rapid interfacial electron-transfer, ket1 = 20 s-1, long time intervals lead to a slow interfacial electron transfer to the Fe(III)-Cyt c, ket2 = 1.5 s-1. The fast interfacial electron-transfer rate-constant is attributed to the reduction of the surface-attracted Fe(III)-Cyt c. The slow interfacial electron-transfer rate constant is attributed to the electrostatic repulsion of the positively charged Cyt c from the electrode surface, resulting in long-range electron transfer exhibiting a lower rate constant. At intermediate time intervals between the oxidative and reductive steps, two populations of Cyt c, consisting of surface-attracted and surface-repelled heme proteins, are observed. Crosslinking of a layered affinity complex between the Cyt c and cytochrome oxidase, COx, on an Au-electrode yields an electrically-contacted, integrated, electrode for the four-electron reduction of O2 to water. Kinetic analysis reveals that the rate-limiting step in the bioelectrocatalytic reduction of O2 by the integrated Cyt c/COx electrode is the primary electron transfer from the electrode support to the Cyt c units.

[Conservative treatment of dislocated proximal humeral fractures]

Between 11/1989 and 6/1998 52 patients (10 m., 42 f., age median 72 years, 31-88) with proximal humeral fractures have been treated by conservative means (angulation of humeral head > 45 degrees and/or shaft displacement > 1 cm and displacement of greater tuberosity > 0.5 cm). In 37 patients (71%, 31 f., 6 m., age median 75 years, 36-88) a clinical and radiological follow-up could be obtained after median 20 months (3-93). According to the Neer-classification, subcapital 2-part fractures were found in 19 cases and 3-part fractures in 12 cases. 4-part fractures were diagnosed in 6 cases. By using the Constant-Score, the final result was scored "excellent" in 10 patients and "good" in 13 patients. In 7 patients each the results achieved were "moderate" or "poor". The underlying cause for the poor results was primarily due to persisting painful impairment in range of motion and loss of strength. Radiologically, persisting axial deviation was present in 23 cases, arthrosis in 14 patients and humeral head necrosis in 8 patients. Most commonly, poor functional and radiological results occurred in 4-part fractures. However, conservative therapy of displaced 2-part and 3-part fractures is a considerable therapeutical option since the final results are predominantly good. In contrast, due to the poor results after conservative therapy 4-part fractures should be treated surgically.

Confirmation of mendelian properties of heterodimeric fibrinogen molecules in a heterozygotic dysfibrinogenemia, "fibrinogen Amarillo," using gprphoresis to differentiate semifibrin molecules from fibrinogen and fibrin

The fibrinogen molecule consists of two sets of Aalpha, Bbeta, and gamma chains assembled into a bilateral disulfide linked (Aalpha, Bbeta, gamma)2 structure. Cleavage of the two A-fibrinopeptides (FPA, Aalpha1-16) from normal Aalpha chains with arginine at position 16 (RFPA) by thrombin or the venom enzyme atroxin transforms fibrinogen into self-aggregating fibrin monomers (alpha, Bbeta, gamma)(2). Mutant Aalpha16R-->H fibrinopeptide (HFPA) cannot be cleaved from fibrinogen by atroxin. Many studies on heterozygous dysfibrinogenemias with this mutation suggested that incorporation of the mutant chains into the molecules was ordered in a manner yielding only (1) homodimeric normal (RFPARFPA) atroxin-coagulable molecules and (2) homodimeric abnormal (H(FPA)HFPA) atroxin-incoagulable molecules in equal quantities. Although heterodimeric molecules (RFPAHFPA) could not be found in studies on the intact protein, Meh et al. demonstrated their existence by showing that CNBr digests of fibrinogens from atroxin-treated Aalpha16R-->H heterozygotic dysfibrinogenemias consistently yielded N-terminal fragments (NDSKs) with partially resolved electrophoretic bands predominantly in between the NDSKs of fibrinogen and alpha-fibrin. An opportunity to confirm and better quantify the heterodimers arose with the recent development of a method (GPRphoresis) for identifying molecules lacking only one FPA, which is applied here in study of a newly presenting case of an Aalpha16R-->H dysfibrinogenemia, "fibrinogen Amarillo." GPRphoresis uses electrophoretic shifts, staged with GPRP-NH(2) to separate the self-aggregating fibrin monomers lacking both FPAs from weakly aggregating "semifibrin" molecules lacking one FPA An antifibrin alpha17-23 antibody is used to measure and differentiate the semifibrin from fibrinogen with FPA fully intact. Applying GPRphoresis to atroxin digests of fibrinogen Amarillo clearly demonstrated RFPARFPA, RFPAHFPA, and HFPAHFPA molecules in nearly perfect Mendelian 1:2:1 proportions. In turn, the high levels of the semifibrin in the terminal atroxin digests provide genetic phenotypic evidence supporting fidelity of the GPRphoresis method.

Specific heterodimer formation by the cytoplasmic domains of the b and b' subunits of cyanobacterial ATP synthase

The soluble domains of the b and b' subunits of the ATP synthase of the cyanobacterium Synechocystis PCC 6803 were expressed with His tags attached to their N-termini. Following purification, the polypeptides were characterized by chemical cross-linking, analytical ultracentrifugation, and circular dichroism spectroscopy. Treatment of a mixture of the soluble b and b' domains with a chemical cross-linking agent led to substantial formation of cross-linked dimers, whereas similar treatment of either domain by itself resulted in only trace formation of cross-linked species. The molecular weights of the domains of b and b' in solution at 20 degrees C, measured by sedimentation equilibrium, were 17 800+/-700 and 16 300+/-400, respectively, compared to calculated polypeptide molecular weights of 16 635 and 15 422, whereas a mixture of b and b' gave a molecular weight of 29 800+/-800. The sedimentation coefficient of an equimolar mixture was 1.73+/-0.03. The circular dichroism spectra of the individual polypeptides indicated helical contents in the range of 40-50%; the spectrum of the mixture revealed changes indicative of coiled-coil formation and a helical content of 60%. The results indicate that the cytosolic domains of the b and b' subunits exist individually as monomers but form a highly extended heterodimer when they are mixed together.

[Retropatellar autologous cartilage-bone transplantation. A treatment option in severe cartilage damage]

In a 32 years old professional handball layer, the micro-traumata typical of this game led to retropatellar cartilage lesion, which became sympthomatic following an distortion-impact trauma. Since the patient remains symptomatic after initial conservative treatment as well as arthroscopic chondroplastic, osteo-chondral transplantation was performed. There was a good functional result 6 months after surgery.

Expression of prokaryotic and eukaryotic cytochromes c in Escherichia coli

C-type cytochromes from various sources show substantial structural conservation. For the covalent attachment of heme groups to apocytochromes, however, three different enzyme systems have been described so far. We have examined the ability of the heme ligation systems of Escherichia coli and of Saccharomyces cerevisiae to process cytochromes from S. cerevisiae, Paracoccus denitrificans, and Synechocystis sp. PCC 6803. E. coli's maturation system with at least eight different proteins accepted all these cytochromes for heme ligation. The single subunit heme lyase from S. cerevisiae mitochondria, on the other hand, failed to attach heme groups to cytochromes of prokaryotic origin.

[Proximal and distal humerus fractures in advanced age]

In contrast to distal humeral fractures, humeral head fractures represent a common injury to the old patient. For both fracture localizations osteoporosis and multi-morbidity are of significant importance. The classification for humeral head fractures in one-, two-, three- and four-part fractures is generally accepted. Valgus impacted head fractures as well as head-splitting fractures are considered a separate entity. In none or minimally displaced fractures good functional results are achieved by conservative means. Although numerous therapeutical procedure are offered in the treatment of displaced fractures of the proximal humerus the result are often disappointing. Generally, minimal invasive surgical procedures should be preferred. However, in dislocated multi-part fractures a primary humeral head replacement is often the treatment of choice. In patients with multifarious morbidity a conservative treatment is always to be included into the therapeutical considerations. Distal fractures of the humerus are classified into extraarticular, intraarticular uni-condylar and intraarticular bi-condylar fractures. The therapeutical recommendations, also in the elderly, is relatively homogeneous: primary open reduction and internal fixation (ORIF) should be carried out aiming for an early postoperative functional treatment. Depending from soft tissue conditions and accompanying injuries the functional results are often good or moderate and are generally comparable to those of younger patients. Following a correct indication for surgical intervention the main priority for both distal and proximal humeral fractures is an early definitive surgical treatment.

[Bilateral posterior fracture-dislocation of the shoulder caused by an epileptic seizure - diagnostic, treatment and result]

The case of an 39-year-old man is presented, who sustained a bilateral locked fracture dislocation of the shoulders occurring during an epileptic seizure. Radiographs demonstrated a compression-fracture of the anteromedial aspect of the humeral head bilaterally (reversed Hill-Sachs-lesions). Additionally, fractures of the lesser and greater tuberosity were diagnosed at the right site. Open reduction and internal fixation was performed in both shoulders within 12 hours. 6 months later the patient has no complaints with a free range of motion. Diagnostics, treatment and result are discussed in context with the literature.

[Conservative treatment after first traumatic shoulder dislocation]

Between January 1989 and March 1997, 175 patients with traumatic shoulder dislocation were treated by conservative means (median age 41 years, 39 F, 136 M). In 78 patients (17 F, 61 M) a clinical and radiological follow up (median 50 months, range 6-106) could be obtained. Additionally, a diagnostic ultrasound was carried out in all patients. The recurrence rate in the group younger than 30 years (G < 30; n = 35) was 86%; in the group older than 30 years (G > 30; n = 43) it was 21% (P < 0.05). Persisting neurological deficits were found in 6 patients (8%). According to the Rowe score, 16 patients (46%) of the G < 30 achieved excellent or good results, in the G > 30, 29 patients (67%). In 17% of cases, a glenohumeral arthrosis was diagnosed be radiological means. 18% had radiological signs of a previous fracture of the greater tuberosity. Hill-Sachs lesions were identified in 19% of cases. Rotator cuff tears were diagnosed in 9% by ultrasound. No relationship between the duration of immobilization and the recurrence rate was found (P = 0.95). The recurrence rate following primary shoulder dislocation depends primarily on the patients' age.

The coupling region of F0F1 ATP synthase: binding of the hydrophilic loop of F0 subunit c to F1

The hydrophilic loop region of the CF0 c subunit has been expressed as a fusion with MalE in Escherichia coli. A cysteine was introduced at the C-terminus to allow fluorophore labeling of the fusion protein. After removal of the MalE moiety, the labeled peptide was used for binding studies with fluorophore-labeled CF1. At saturation, 1 mol peptide was bound per mol CF1. Binding was abolished after removal of subunit epsilon from CF1, and partially restored by addition of recombinant epsilon.

[Acromioclavicular joint injuries: efficient therapy from the economic viewpoint]

The results of surgical treatment with tension band wiring versus conservative therapy with bandages are described in a retrospective study. Operative therapy is associated with complications in 32.3% and two occasions of hospitalisation. The advantages of conservative therapy are obvious: it is easy and comfortable for the patient; there are no complications and low costs, and it is associated with a shorter temporary disablement. Therefore, conservative therapy is our standard, and surgery is performed only for Rockwood IV-VI lesions and in exceptional cases.

Fluorescence resonance energy transfer mapping of subunit delta in spinach chloroplast F1 ATPase

Despite the considerable progress in the field of F0F1-ATPases caused by solving the 2.8-A structure of mitochondrial F1 ATPase [Abrahams, J. P., Leslie, A. G. W., Lutter, R. & Walker, J. E. (1994) Nature 370, 621-628], little is known about the position and function of the enzyme's small subunits which were not resolved in the X-ray analysis. We have previously genetically engineered Cys residues into the delta subunit of chloroplast F1 and used these mutant subunits in cross-linking studies [Lill, H., Hensel, F., Junge, W. & Engelbrecht, S. (1996) J. Biol. Chem. 271, 32737-32742]. In this work, various fluorophores have been introduced into the mutant delta subunits and used in fluorescence-resonance energy-transfer measurements. The resulting distances were fitted into the framework of existing data. Subunit delta was found to be located between two alpha/beta couples, stretching from the level of the nucleotide binding sites up to a position close to the N-termini of subunits alpha and beta. These results corroborate and further refine the previously found location of spinach CF1 delta at the periphery and membrane-distal part of CF1, where it may constitute a part of a stator in the rotatory machinery of F0F1.

ATP synthase: an electrochemical transducer with rotatory mechanics

ATP synthase (F0F1-ATPase) uses proton- or sodium-motive force to produce ATP form ADP and P(i). Three lines of experiment have recently demonstrated large-scale intersubunit rotation during ATP hydrolysis by F1. We discuss how ion flow through the membrane-intrinsic portion, F0, may generate torque and how this might be transmitted between stator and rotor to finally expel spontaneously formed ATP from F1 into water.

[T-plate osteosynthesis in dislocated proximal humerus fractures]

From 1988 through 1995 we operated 48 patients with dislocated humeral fractures using the T-Plate (median age 66 years [20 to 90 years], 32 male, 16 female). After a median 22 months (9 to 60 months) 33 patients were followed up clinically and radiologically. Six patients had suffered a 2-part fracture, 17 a 3-part fracture, and 10 a 4-part fracture. Judged by the Constant score 6 patients reached a very good result, 8 had a good result, 4 a satisfactory and 15 a poor result. Radiologically we saw an arthrosis in 31%, an axial deviation in 50%, and a dislocation of the fragments in 72%. The rate of necrosis of the humeral head was 39%. MRI (17 patients) provided additional relevant information about soft tissue and bone quality and is valuable in the early detection of necrosis of the humeral head. Functionally poor results correlated rather to dislocated fragments and persisting axial deviation than to the type of fracture or the necrosis of the humeral head. The T-plate osteosynthesis is one way to treat dislocated fractures of the proximal humerus, if early operation, correct reposition, and biological principles are respected.

Cross-linking of chloroplast F0F1-ATPase subunit epsilon to gamma without effect on activity. Epsilon and gamma are parts of the rotor

Cys residues were directed into positions 17, 28, 41 and 85 of a Cys6-->Ser mutant of subunit epsilon of spinach chloroplast F0F1 ATP synthase. Wild-type and engineered epsilon were expressed in Escherichia coli, purified in the presence of urea, refolded and reassembled with spinach chloroplast F1 lacking the epsilon subunit [F1(-epsilon)]. Cys-containing epsilon variants were modified with a sulfhydryl-reactive photolabile cross-linker. Photocross-linking of epsilon to F1(-epsilon) yielded the same SDS gel pattern of cross-link products independent of the presence or absence of Mg2+ x ADP, phosphate and Mg2+ x ATP. Epsilon (wild type) [Ser6,Cys28]epsilon and [Ser6,Cys41]epsilon were cross-linked with subunit gamma. With chloroplast F0F1 the same cross-link pattern was obtained, except for one extra cross-link, probably between [Ser6,Cys28]epsilon and F0 subunit III. [Ser6,Cys17]epsilon and [Ser6,Cys85]epsilon did not produce cross-links. Cross-linking of epsilon, [Ser6,Cys28]epsilon, [Ser6,Cys41]epsilon to gamma in soluble chloroplast F1 impaired the ability of epsilon to inhibit Ca2+-ATPase activity. The Mg2+-ATPase activity of soluble F1 (measured in the presence of 30% MeOH) was not affected by cross-linking epsilon with gamma. Functional reconstitution of photophosphorylation in F1-depleted thylakoids was observed with F1 in which gamma was cross-linked to [Ser6,Cys28]epsilon or [Ser6,Cys41]epsilon but not with wild-type epsilon. In view of the intersubunit rotation of gamma relative to (alphabeta)3, which is driven by ATP hydrolysis, gamma and epsilon would seem to act concertedly as parts of the 'rotor' relative to the 'stator' (alphabeta)3.