Effectiveness of a stepped care intervention for anxiety and depression in people with diabetes, asthma or COPD in primary care: A randomized controlled trial.

BACKGROUND: Depression and anxiety are common in people with a chronic somatic disease. Although guidelines recommend stepped care, the effectiveness of this approach has not been evaluated in people with diabetes, asthma, or COPD in primary care. METHODS: 3559 People were sent screening questionnaires (41% response). Of 286 persons with anxiety and/or depression (Generalized Anxiety Disorder questionnaire, GAD-7, cut-off ≥ 8 and/or Patient Health Questionnaire, PHQ-9, cut-off ≥ 7), 46 were randomized into the intervention (stepped care and monitoring of symptoms; n = 23) or control (usual care) group (n = 23). Main outcomes were symptoms of anxiety and depression after the 12-months intervention and six months post intervention. Analysis of covariance was first adjusted for condition and baseline GAD-7/PHQ-9 scores and additionally for age, sex and education. RESULTS: The intervention group had a significantly lower level of anxiety symptoms at the end of the program (GAD-7 6 ± 6 vs. 9 ± 6; Cohen's d = 0.61). This effect was still present six months post intervention. The effect on depression was statistically significant in the first model (PHQ-9 6 ± 4 vs. 9 ± 6; p = 0.035), but not in the fully adjusted model (p = 0.099), despite a large effect size (d = 0.63). At six months post intervention there was no statistically significant difference in symptoms of depression between the two groups although the difference in symptoms was still clinically significant (Cohen's d = 0.61). LIMITATIONS: Many people were screened, but relatively few participated in the randomized controlled trial. CONCLUSIONS: Stepped care with monitoring resulted in a lower level of symptoms of anxiety and depression in people with a chronic condition.

Soluble CD83 ameliorates experimental colitis in mice.

The physiological balance between pro- and anti-inflammatory processes is dysregulated in inflammatory bowel diseases (IBD) as in Crohn's disease and ulcerative colitis. Conventional therapy uses anti-inflammatory and immunosuppressive corticosteroids to treat acute-phase symptoms. However, low remission rate and strong side effects of these therapies are not satisfying. Thus, there is a high medical need for new therapeutic strategies. Soluble CD83, the extracellular domain of the transmembrane CD83 molecule, has been reported to have interesting therapeutic and immunosuppressive properties by suppressing dendritic cell (DC)-mediated T-cell activation and inducing tolerogenic DCs. However, the expression and function of CD83 in IBD is still unknown. Here, we show that CD83 expression is upregulated by different leukocyte populations in a chemical-induced murine colitis model. Furthermore, in this study the potential of sCD83 to modulate colitis using an experimental murine colitis model was investigated. Strikingly, sCD83 ameliorated the clinical disease symptoms, drastically reduced mortality, and strongly decreased inflammatory cytokine expression in mesenteric lymph nodes and colon. The infiltration of macrophages and granulocytes into colonic tissues was vigorously inhibited. Mechanistically, we could show that sCD83-induced expression of indolamine 2,3-dioxygenase is essential for its protective effects.

[Unexpected revision procedures treating ankle fractures]. / Ungeplante Zweiteingriffe nach Frakturen des oberen Sprunggelenks.

The purpose of the present study was to analyze the risk factors associated with unexpected second procedures and strategies of revision surgery. Within a 5 year period 647 patients with closed ankle fractures AO type 44 were identified of which 77 (11.9%) needed revision surgery. Complications were addressed to 4 main groups: deep infections (IG) were seen in 29 patients (4.5%), problems with primary wound closure (WG) in 22 patients (3.4%), insufficient reduction (KG) in 22 patients (3.4%) and other causes (RG) included 4 patients (0.6%). Significant predictive factors for soft tissue complications were higher age, comorbidities with peripheral arteriosclerosis, high American Society of Anesthesiologists (ASA) score and diabetes mellitus. AO 44 type B2 and B3 fractures were often associated with soft tissue problems. The more complex fracture types AO 44 C1-C3 and A2-A3 were significantly associated with problems of insufficient congruency post-surgery. The distribution of the mean revision rate was significantly different (p<0.01) for all groups: IG 4.59, WG 3.5, KG 1.55, RG 1.25. In summary, we strongly recommend immediate reduction of displaced fractures and to consider a more detailed fracture classification. To reduce the amount of unexpected ankle procedures individual risk factors should be weighed against the advantages of optimal open reduction and internal fixation.

Topo-proteomic in situ analysis of psoriatic plaque under efalizumab treatment.

In a pilot study 6 psoriasis patients were treated over 12 weeks with efalizumab targeting the CD11a subunit of LFA-1. The treatment was well tolerated. Five of these patients proved to be responders with an average decrease in psoriasis area and severity index (PASI) from 21.3 +/- 5.4 (day 0) to 3.9 +/- 0.6 (week 12). The nonresponder was subsequently successfully treated with cyclosporin. Skin biopsies were taken before and after efalizumab treatment and subjected to Multi-Epitope Ligand Cartography (MELC) robot microscopy. A MELC library of 46 antibodies including FITC-labeled efalizumab was chosen focusing upon inflammatory epitopes. Quantification of marker expression was performed using a special adaptation to the needs of skin tissue in terms of pixel events normalized to a standardized horizontal skin width of 100 mum. The before-versus-after comparison for the responders revealed at the 'single epitope level' of MELC analysis a significant decrease (p < 0.05) in epidermal thickness (represented by pan-cytokeratin, CD71, CD138), of the expression of common leukocyte antigen (CD45), T-cell markers (CD2, CD4, CD8, CD45R0), CD11a, efalizumab binding site (EfaBS), and CD58. At the 'EfaBS-centered, double colocation level' a corresponding decrease was observed for CD2, CD3, CD4, CD8, CD11a, CD13, CD26, CD44, CD45, CD45R0, CD54, CD62L, HLA-DR, and TIA-1. MELC analysis at the 'multicombinatorial level' revealed predominant combinatorial molecular phenotype (CMP) motifs, which showed an efalizumab treatment-dependent significant decrease. These CMP motifs were defined as toponomic combinations of lead markers for (i) leukocytes in general (CD45), (ii) T cells (CD2, CD3, CD4, CD45R0, CD45RA), (iii) macrophages (CD68), (iv) cell activation (CD13, CD26, HLA-DR), and (v) cell adhesion (CD11a, EfaBS). Thirty-five of the most relevant 50 CMP motifs were directly related to the T-cell type. A descriptive statistical analysis of the nonresponder before treatment showed a below-responder range degree of expression for CD4, CD8, CD44 (H-CAM), CD56, CD62L, HLA-DQ, and also for these epitopes in colocation with EfaBS. In the nonresponder and before treatment we observed an above-responder range degree of expression for CD54 (ICAM-1) as LFA-1 ligand. In conclusion, the topo-proteomic data provide new diversified insights into the pleiotropic cellular dynamics in psoriatic skin lesions under effective efalizumab treatment. Moreover, the data may be relevant to the future development of possible strategies for individual prediction of efalizumab treatment response or nonresponse.

The CD11a binding site of efalizumab in psoriatic skin tissue as analyzed by Multi-Epitope Ligand Cartography robot technology. Introduction of a novel biological drug-binding biochip assay.

Efalizumab (Raptiva) is an immunomodulating recombinant humanized IgG1 monoclonal antibody that binds to CD11a, the alpha-subunit of leukocyte function antigen-1 (LFA-1). By blocking the binding of LFA-1 to ICAM-1, efalizumab inhibits the adhesion of leukocytes to other cell types and interferes with the migration of T lymphocytes to sites of inflammation (including psoriatic skin plaques). Analysis of the response in patients treated with efalizumab to date shows that distinct groups of responders and nonresponders to the drug exist. It would therefore be of great practical value to be able to predict which patients are most likely to respond to treatment, by identifying key parameters in the mechanism of action of efalizumab. Detailed investigation and detection of multiple epitopes in microcompartments of skin tissue has until recently been restricted by the available technology. However, the newly developed technique of Multi-Epitope Ligand Cartography (MELC) robot technology combines proteomics and biomathematical tools to visualize protein networks at the cellular and subcellular levels in situ, and to decipher cell functions. The MELC technique, which is outlined in this paper, was used to help characterize the binding of efalizumab to affected and unaffected psoriatic skin as compared to normal control skin under ex vivomodel conditions. Efalizumab was labeled with fluorescein isothiocyanate and integrated into a MELC library of more than 40 antibodies. These antibodies were selected for their potential to detect epitopes which may be indicative of (a) various cell types, (b) structural components of the extracellular matrix, or (c) the processes of cell proliferation, activation and adhesion. Efalizumab bound to CD11a in affected psoriatic skin by a factor 15x and 32x higher than in unaffected psoriatic skin and normal control skin, respectively. CD11a and the efalizumab binding site were primarily expressed in the extravascular dermis, whereas CD54 (ICAM-1) as its ligand was most prevalent in the dermal vessels. T lymphocytes (for which the markers were CD3, CD8, CD4, and CD45R0) were the major cellular targets of efalizumab. In contrast, NK cells were only a minor target of efalizumab. Our study demonstrated that efalizumab represents a treatment for psoriasis that primarily targets memory CD4+ and CD8+ T cells and has a high specificity for psoriatic disease activity. Moreover, we hereby introduce the novel principle of a biological drug-binding biochip assay being especially useful for the future monitoring of psoriatic skin lesions under efalizumab treatment conditions.

[Application of low intensity, pulsed ultrasound on distraction osteogenesis of the humerus. Case report]. / Anwendung von niederenergetischem gepulstem Ultraschall bei der Kallusdistraktion am Humerus. Fallbeispiel.

Low intensity pulsed ultrasound accelerates fracture healing both clinically and experimentally. Based on recently published animal studies, an improvement in regenerative bone maturation after distraction osteogenesis due to low intensity, pulsed ultrasound is also expected. We report on an 18 year-old female patient suffering from an acquired shortening of the right upper arm of 10 cm after humeral osteitis as a baby. The patient was admitted to hospital for corticotomy and distraction osteogenesis at the afflicted humerus. Due to the published experimental results in animals which indicate an improvement in bone regeneration during callotasis with the additional application of low intensity, pulsed ultrasound, we decided to try this procedure. The calculated distraction consolidation index was 21 days/cm, which is below the mean of 30 days/cm reported in the literature for humeral lengthening by distraction osteogenesis. The calculated healing index according to Paley was 0.7 months/cm in our patient. Compared to reference data, in which a range of from 0.87 months/cm to 1.5 months/cm is reported, our patient showed an accelerated maturation of distraction callus. The duration of treatment of the patient was clearly shortened by the additional application of low intensity, pulsed ultrasound. If distraction osteogenesis is correctly indicated, the early use of low intensity, pulsed ultrasound should be considered, since an acceleration of callus formation with consecutive shortening of treatment time could be attained while wearing an external fixator, leading to a decrease in cumulative complications, such as pin tract infections. Further studies from our research group regarding this topic will follow.

[Efficiency of low-intensity pulsed ultrasound on distraction osteogenesis in case of delayed callotasis -- clinical results]. / Wirksamkeit von niederenergetischem, gepulstem Ultraschall im Fall des drohenden Regeneratversagens bei der Kallusdistraktion -- klinische Behandlungsergebnisse.

AIM: Low-intensity pulsed ultrasound has been proven to accelerate fracture healing both clinically and experimentally. In this study the influence of low-intensity pulsed ultrasound during distraction-osteogenesis in case of delayed callotasis was investigated. METHOD: 20 patients could be included in this study. 16 patients initially were treated because of fractures of the lower leg, 2 because of fractures of the femur with resulting shortening of the afflicted limb. One patient suffered from chronic osteitis at the thigh and one from chronic osteitis at the upper arm without previous trauma. Because of delayed callotasis an adjunctive ultrasound treatment device was transcutaneously applied (frequency 1.5 MHz, signal burst width 200 microseconds, signal repetition frequency 1.0 kHz, intensity 30 mW/cm (2)) with the transducer placed at the distraction zone for 20 minutes daily. In all cases in-home treatment was performed. Evaluation was done by radiographic and sonographic controls of the distraction zone during examination of all patients at the outpatients' department every 3-4 weeks. RESULTS: Progress of callotasis was achieved in 15 out of 20 patients. Patients who were smokers during ultrasound therapy showed lower healing rates than those who never smoked. 2 patients suffering from osteitis of the tibia and missing callotasis had to be amputated. 3 other patients needed additional operative treatment including cancellous bone grafts because of missing new bone formation. Negative effects of low-intensity pulsed ultrasound during therapy could not be detected. CONCLUSION: We conclude that ultrasound treatment can accelerate bone maturation and formation in distraction osteogenesis, sometimes even in states of poor callotasis. It may provide a method of great promise in cases where delayed bone formation during distraction osteogenesis occurs.

Confidential storage and transmission of medical image data.

We discuss computationally efficient techniques for confidential storage and transmission of medical image data. Two types of partial encryption techniques based on AES are proposed. The first encrypts a subset of bitplanes of plain image data whereas the second encrypts parts of the JPEG2000 bitstream. We find that encrypting between 20% and 50% of the visual data is sufficient to provide high confidentiality.

Mechanism and cleavage specificity of the H-N-H endonuclease colicin E9.

Colicin endonucleases and the H-N-H family of homing enzymes share a common active site structural motif that has similarities to the active sites of a variety of other nucleases such as the non-specific endonuclease from Serratia and the sequence-specific His-Cys box homing enzyme I-PpoI. In contrast to these latter enzymes, however, it remains unclear how H-N-H enzymes cleave nucleic acid substrates. Here, we show that the H-N-H enzyme from colicin E9 (the E9 DNase) shares many of the same basic enzymological characteristics as sequence-specific H-N-H enzymes including a dependence for high concentrations of Mg2+ or Ca2+ with double-stranded substrates, a high pH optimum (pH 8-9) and inhibition by monovalent cations. We also show that this seemingly non-specific enzyme preferentially nicks double-stranded DNA at thymine bases producing 3'-hydroxy and 5'-phosphate termini, and that the enzyme does not cleave small substrates, such as dinucleotides or nucleotide analogues, which has implications for its mode of inhibition in bacteria by immunity proteins. The E9 DNase will also bind single-stranded DNA above a certain length and in a sequence-independent manner, with transition metals such as Ni2+ optimal for cleavage but Mg2+ a poor cofactor. Ironically, the H-N-H motif of the E9 DNase although resembling the zinc binding site of a metalloenzyme does not support zinc-mediated hydrolysis of any DNA substrate. Finally, we demonstrate that the E9 DNase also degrades RNA in the absence of metal ions. In the context of current structural information, our data show that the H-N-H motif is an adaptable catalytic centre able to hydrolyse nucleic acid by different mechanisms depending on the substrate and metal ion regime.

TGFbeta1 and TGFbeta2 mRNA and protein expression in human bone samples.

Transforming growth factor beta is one of the most abundant growth factors stored in bone. It is known as a potent regulator of osteoblast proliferation and differentiation as well as of production extracellular matrix. We established a highly specific RT-PCR in combination with HPLC for detection and quantification of TGFbeta1 and TGFbeta2 mRNA expression in 89 human bone samples. Levels of TGFbeta1 protein ranged between 27 and 580 ng/g bone (mean 188 +/- 15 ng/g; n=75) and for TGFbeta2 between 7.2 and 35 ng/g bone (mean 14.3 +/- 2.1 ng/g; n=57). TGFbeta1 and TGFbeta2 protein concentrations and TGFbeta isoform mRNA expression in bone were not significantly different between the sexes. TGFbeta isoform mRNA expression as well as protein content in bone declined age dependently. TGFbeta1 and TGFbeta2 protein and mRNA expression were different in bone samples from different sites of the skeleton indicating in part the regulation by mechanical stimuli. In contrast to TGFbeta1, TGFbeta2 mRNA expression was significantly enhanced in osteoarthritic bone compared to unaffected bone. These data are in concordance to previous results concerning the expression of TGFbeta3 in bone. In conclusion, the data suggest distinct patterns' of expression of the TGFbeta isoforms under physiological and pathological conditions in bone.

Analysis of TGFbeta3 gene expression and protein levels in human bone and serum.

Recent data indicate that TGFbeta3, one member of the TGFbeta-isoforms, has an important role in bone remodeling. Up to date little is known about the expression and regulation of TGFbeta3 in man. We established a highly specific ELISA for quantitative measurement of TGFbeta3 in bone and blood samples and a RT-PCR in combination with HPLC for detection and quantification of TGFbeta3 mRNA in 89 human bone samples. Levels of TGFbeta3 protein ranged between 30 and 66 pg/mg bone (mean 36,6 +/-1,03 pg/mg) and between 30 and 1910 pg/ml in serum (mean 128.9+/-38.9 pg/ml). TGFbeta3 mRNA expression as well as protein levels in serum and in bone declined age dependently. No specific load- or site-specific distribution of TGFbeta3 mRNA expression or protein content was detected at different sites indicating an absence of mechanical regulation. Protein levels of TGFbeta3 in serum correlated with TGFbeta3 mRNA expression in bone (p= 0.0027; r=0.49). By contrast, TGFbeta3 protein levels stored in the bone matrix were not related to TGFbeta3 mRNA reflecting the long term process of TGFbeta3 deposition during bone remodeling. Notably TGFbeta3 serum levels were highly correlated with IGF-I and osteocalcin levels in serum. We conclude that TGFbeta3 in man circulates in significant amounts which appears to be representative for TGFbeta3 expression in bone tissue and may be in part derived from bone. The high correlation of TGFbeta3 with IGF-I suggests parallel systemic principles of regulation.

Specificity in protein-protein interactions: the structural basis for dual recognition in endonuclease colicin-immunity protein complexes.

Bacteria producing endonuclease colicins are protected against their cytotoxic activity by virtue of a small immunity protein that binds with high affinity and specificity to inactivate the endonuclease. DNase binding by the immunity protein occurs through a "dual recognition" mechanism in which conserved residues from helix III act as the binding-site anchor, while variable residues from helix II define specificity. We now report the 1.7 A crystal structure of the 24.5 kDa complex formed between the endonuclease domain of colicin E9 and its cognate immunity protein Im9, which provides a molecular rationale for this mechanism. Conserved residues of Im9 form a binding-energy hotspot through a combination of backbone hydrogen bonds to the endonuclease, many via buried solvent molecules, and hydrophobic interactions at the core of the interface, while the specificity-determining residues interact with corresponding specificity side-chains on the enzyme. Comparison between the present structure and that reported recently for the colicin E7 endonuclease domain in complex with Im7 highlights how specificity is achieved by very different interactions in the two complexes, predominantly hydrophobic in nature in the E9-Im9 complex but charged in the E7-Im7 complex. A key feature of both complexes is the contact between a conserved tyrosine residue from the immunity proteins (Im9 Tyr54) with a specificity residue on the endonuclease directing it toward the specificity sites of the immunity protein. Remarkably, this tyrosine residue and its neighbour (Im9 Tyr55) are the pivots of a 19 degrees rigid-body rotation that relates the positions of Im7 and Im9 in the two complexes. This rotation does not affect conserved immunity protein interactions with the endonuclease but results in different regions of the specificity helix being presented to the enzyme.

[Therapeutic possibilities in trochanteric fractures. Safe--fast--stable]. / Therapiemöglichkeit trochantärer Frakturen. Sicher--schnell--stabil.

Trochanteric fractures frequently occur in elder patients with severe osteopenia. These fractures are highly unstable. Conservative treatment is not indicated because of the long period of immobilization until fracture healing is achieved. Simple fractures (A1) can be successfully fixed by either plate-hip screw systems like Dynamic Hip Screw (DHS) or nail-hip screw systems (Gamma-Nail, Proximal Femur Nail, Classic Nail). As a result of biomechanical and clinical trials the intramedullary implants should be preferred for fixation of more comminuted fractures (Type A2.2, A3.3) and subtrochanteric fractures. For ipsilateral femoral shaft and trochanteric fractures long nail-hip screw-systems are recommended like the long PFN or the long Gamma nail. In about 90% of the patients with trochanteric fractures postoperative weight bearing can be achieved by internal fixation if gliding systems are applied. Intraoperative and postoperative complications however occur more frequently after the implantation of Gamma-Nail than after application of a DHS. Other implants like Ender Nails, 130 degrees angled plate or twisted plate are not further recommended.

Fixation of proximal tibia fractures by a retrograde nail: a biomechanical investigation.

Surgical treatment of proximal tibial fractures requires open reduction and internal fixation. The operative exposure causes additional soft-tissue injury and reduces the blood supply to the bone. A cephalograde tibial nail should offer comparable mechanical stability without these disadvantages. We compared the stability of both osteosyntheses in a fracture model with 12 fresh-frozen cadaver bones. While both implants exhibited comparable stiffness under sagittal loading, the plate had a higher rotational and varus stiffness. Despite this higher stiffness, rotational displacements at the fracture gap were nearly twice as large for this implant during loading. We conclude that the retrograde nail provides similar mechanical stability to plate fixation for proximal tibial fractures, while the closed reduction and soft-tissue preservation of this new technique are definite advantages.

[Surgical treatment of injuries of the thoracolumbar transition. 2: Operation and roentgenologic findings]. / Operative Behandlung von Verletzungen des thorakolumbalen Ubergangs. Teil 2: Operation und röntgenologische Befunde.

The authors report on a prospective multicenter study with regard to the operative treatment of acute fractures and dislocations of the thoracolumbar spine (T10-L2). The study should analyze the operative methods currently used and determine the results in a large representative collective. This investigation was realized by the working group "spine" of the German Trauma Society. Between September 1994 and December 1996, 682 patients treated in 18 different traumatology centers in Germany and Austria were included. Part 2 describes the details of the operative methods and measured data in standard radiographs and CT scans of the spine. Of the patients, 448 (65.7%) were treated with posterior, 197 (28.9%) with combined posterior-anterior, and 37 (5.4%) with anterior surgery alone. In 72% of the posterior operations, the instrumentation was combined with transpedicular bone grafting. The combined procedures were performed as one-stage operations in 38.1%. A significantly longer average operative time (4:14 h) was noted in combined cases compared to the posterior (P < 0.001) or anterior (P < 0.05) procedures. The average blood loss was comparable in both posterior and anterior groups. During combined surgery the blood loss was significantly higher (P < 0.001; P < 0.05). The longest intraoperative fluoroscopy time (average 4:08 min) was noticed in posterior surgery with a significant difference compared to the anterior group. In almost every case a "Fixateur interne" (eight different types of internal fixators) was used for posterior stabilization. For anterior instrumentation, fixed angle implants (plate or rod systems) were mainly preferred (n = 22) compared to non-fixed angle plate systems (n = 12). A decompression of the spinal canal (indirect by reduction or direct by surgical means) was performed in 70.8% of the neurologically intact patients (Frankel/ASIA E) and in 82.6% of those with neurologic deficit (Frankel/ASIA grade A-D). An intraoperative myelography was added in 22% of all patients. The authors found a significant correlation between the amount of canal compromise in preoperative CT scans and the neurologic deficit in Frankel/ASIA grades. The wedge angle and sagittal index measured on lateral radiographs improved from -17.0 degrees and 0.63 (preoperative) to -6.3 degrees and 0.86 (postoperative). A significantly (P < 0.01) stronger deformity was noted preoperatively in the combined group compared to the posterior one. The segmental kyphosis angle improved by 11.3 degrees (8.8 degrees with inclusion of the two adjacent intervertebral disc spaces). A significantly better operative correction of the kyphotic deformity was found in the combined group. In 101 (14.8%) patients, intra- or postoperative complications were noticed, 41 (6.0%) required reoperation. There was no significant difference between the three treatment groups. Of the 2264 pedicle screws, 139 (6.1%) were found to be misplaced. This number included all screws, which were judged to be not placed in an optimal direction or location. In seven (1.0%) patients the false placement of screws was judged as a complication, four (0.6%) of them required revision. The multicenter study determines the actual incidence of thoracolumbar fractures and dislocations with associated injuries and describes the current standard of operative treatment. The efforts and prospects of different surgical methods could be demonstrated considering certain related risks. The follow-up of the population is still in progress and the late results remain for future publication.

Homing in on the role of transition metals in the HNH motif of colicin endonucleases.

The cytotoxic domain of the bacteriocin colicin E9 (the E9 DNase) is a nonspecific endonuclease that must traverse two membranes to reach its cellular target, bacterial DNA. Recent structural studies revealed that the active site of colicin DNases encompasses the HNH motif found in homing endonucleases, and bound within this motif a single transition metal ion (either Zn(2+) or Ni(2+)) the role of which is unknown. In the present work we find that neither Zn(2+) nor Ni(2+) is required for DNase activity, which instead requires Mg(2+) ions, but binding transition metals to the E9 DNase causes subtle changes to both secondary and tertiary structure. Spectroscopic, proteolytic, and calorimetric data show that, accompanying the binding of 1 eq of Zn(2+), Ni(2+), or Co(2+), the thermodynamic stability of the domain increased substantially, and that the equilibrium dissociation constant for Zn(2+) was less than or equal to nanomolar, while that for Co(2+) and Ni (2+) was micromolar. Our data demonstrate that the transition metal is not essential for colicin DNase activity but rather serves a structural role. We speculate that the HNH motif has been adapted for use by endonuclease colicins because of its involvement in DNA recognition and because removal of the bound metal ion destabilizes the DNase domain, a likely prerequisite for its translocation across bacterial membranes.

NMR study of Ni2+ binding to the H-N-H endonuclease domain of colicin E9.

Ni2+ affinity columns are widely used for protein purification, but they carry the risk that Ni2+ ions may bind to the protein, either adventitiously or at a physiologically important site. Dialysis against ethylenediaminetetraacetic acid (EDTA) is normally used to remove metal ions bound adventitiously to proteins; however, this approach does not always work. Here we report that a bacterial endonuclease, the DNase domain of colicin E9, binds Ni2+ acquired from Ni2+ affinity columns, and appears to bind [Ni(EDTA)(H2O)n]2- at low ionic strength. NMR was used to detect the presence of both Ni2+ coordinated to amino acid side chains and [Ni(EDTA)(H2O)N]2-. Dialysis against > or =0.2 M NaCl was required to remove the [Ni(EDTA)(H2O)n]2-. The NMR procedure we have used to characterize the presence of Ni2+ and [Ni(EDTA)(H2O)n]2- should be applicable to other proteins where there is the possibility of binding paramagnetic metal ions that are present to expedite protein purification. In the present case, the binding of Ni2+ seems likely to be physiologically relevant, and the NMR data complement recent X-ray crystallographic evidence concerning the number of histidine ligands to bound Ni2+.

Structural and mechanistic basis of immunity toward endonuclease colicins.

The crystal structure of the cytotoxic endonuclease domain from the bacterial toxin colicin E9 in complex with its cognate immunity protein Im9 reveals that the inhibitor does not bind at the active site, the core of which comprises the HNH motif found in intron-encoded homing endonucleases, but rather at an adjacent position leaving the active site exposed yet unable to bind DNA because of steric and electrostatic clashes with incoming substrate. Although its mode of action is unorthodox, Im9 is a remarkably effective inhibitor since it folds within milliseconds and then associates with its target endonuclease at the rate of diffusion to form an inactive complex with sub-femtomolar binding affinity. This hyperefficient mechanism of inhibition could be well suited to other toxic enzyme systems, particularly where the substrate is a polymer extending beyond the boundaries of the active site.

[Surgical treatment of injuries of the thoracolumbar transition. 1: Epidemiology]. / Operative Behandlung von Verletzungen des thorakolumbalen Ubergangs. Teil 1: Epidemiologie.

The authors report on a prospective multicenter study with regard to the operative treatment of fractures and dislocations of the thoracolumbar spine. 18 traumatologic centers in Germany and Austria, forming the working group "spine" of the German Society of Trauma Surgery, are participating in this continuing study. Between September 1994 and December 1996 682 patients (64% male) with an average age of 39 1/2 (7-83) years were entered. The entry criteria included all patients with acute and operatively treated (within 3 weeks after trauma) fractures and dislocations of the thoracolumbar spine (Th 10-L 2). Part 1 of this publication outlines the protocol and epidemiologic data. The incidence of fractures and dislocations of the thoracolumbar spine and associated injuries were recorded according to a standardized protocol, as well as the different operative methods and complications, duration of hospital stay, rehabilitation and incapacity. The analysis of the clinical social and radiological course was a second focus. The most frequent mechanism of injury was a fall (50%) or traffic accident (22%). Most of the fractures occurred at the L 1 level (49%). All injuries were classified according to the ASIF (AO) classification. 65% sustained an A-type fracture (compression fracture). Associated injuries were observed in 35% and 6% were polytraumatized. Extremities and thorax were most frequently affected. Younger age and traffic accidents lead more often to C-type fracture (fracture dislocation) and polytrauma. An increased number of multisegmental or multilevel lesions were observed in polytraumatized patients. There were 16% with incomplete paraplegia (Frankel/ASIA B-D) and 5% with complete paraplegia (Frankel/ASIA A). The rate of patients with initial neurologic deficits significantly increased with the severity of spinal injury according to the Magerl classification. Until discharge a neurologic improvement (at least 1 Frankel/ASIA grade) was observed in 32% of the partially paralyzed (Frankel/ASIA B-D) and in 12% of the patients with complete paraplegia (Frankel/ASIA A). A neurologic deterioration occurred in 3 patients (0.4%). As a base for further follow-up and late results the individual starting point was determined by collecting relevant data of the patients' history: 277 (40.6%) patients suffered from simultaneous diseases, one half was spine related. At the time of injury 559 (82.0%) patients were employed; 429 (62.9%) doing manual work. 369 (54.1%) patients stated sportive activities before the injury and 561 (82.3%) designated their "back function" as normal. For the time before injury the patients scored an average of 93.4 points in the Hannover Spine Score (0-100 points concerning complaints and function of the back/spine).

[Loosening of Schanz screws in external fixator montage of the lower extremity]. / Das Lockerungsverhalten von Schanz-Schrauben bei Fixateur-externe-Montagen an der unteren Extremität.

We analyzed the failure of Schanz pins in 234 patients with fractures of the lower extremity. All patients had the AO external fixator and stainless steel pins (ISO 58/32-1). The mean duration of treatment was 14 weeks. During this time 88 of a total of 1147 pins became loose. The first failures occurred 2 weeks after insertion. Most pins failed after 5-6 weeks. Early loosening was not accompanied signs of local infection, while late failures regularly developed pintract infections. Pins next to the fracture gap exhibited the highest rate of loosening. Intermediate pins had the lowest one. We could not detect an effect of the configuration of the external fixation. Eighty-one percent of the failed pins were exchanged consequently. We conclude that the early occurrence of pin loosening is due to mechanical reasons. Significant factors for this complications were the location close to the fracture gap and the number of pins in that segment.