Biomedical subjects

B König

Publications and source records attributed to B König.

At least 19 recordsLinked to original sources

PubMed2006

[Clinical experience with the Siremobil Iso-C(3D) imaging system in pelvic surgery].

In pelvic and acetabular surgery intraoperative control of reduction and implant position is sometimes hard to achieve with conventional C-arm technology. The Siemens C-arm Iso-C(3D) imaging system enables axial cuts and two- or three-dimensional reconstructions to be generated. Following the good experience in surgery of the spine and extremities, its clinical applicability in pelvic surgery was evaluated in 30 patients in a prospective clinical trial. In all 20 patients with acetabular fractures reduction quality and implant position could be well assessed. In one postoperative examination an intraarticular screw placement was evident, which intraoperatively was not as clear and was revised. In one procedure an intraarticular fragment was visualized, and was extracted in the same procedure. In one procedure the use of the Iso-C(3D) system enabled the approach to be limited. In all ten pelvic ring injuries the osseous structures in the posterior pelvic ring could be visualized with an adequate image quality. Reduction quality and implant position could be assessed in all open and closed procedures. On two occasions the SI screws were navigated based upon the Iso-C(3D) dataset. Overall the use of the Iso-C(3D) system was successful in all cases. Image quality, which is clearly inferior to that of CT, was sufficient for the assessment of reduction quality and implant position. One revision was indicated, and one avoided. However, in spite of its advantages in pelvic surgery, handling, sterile covering and data transfer need to be improved. For bilateral pelvic injuries the image size is too small.

Acetabulum↗

PubMed2006

[Percutaneous reduction and stabilization of a dislocated acetabular fracture. Case report].

In the treatment of acetabular fractures, anatomic reconstruction of the joint is the primary aim. To achieve this, rather large approaches with approach-related morbidity are needed. Percutaneous stabilizations are still limited to nondisplaced or minimally displaced fractures. For displaced acetabular fractures there are percutaneous procedures described with intraoperative CT control, requiring that CT be available in the OR and posing a logistic challenge. The fluoroscope Siremobil Iso-C3D offers the possibility of displaying osseous structures with CT-like quality using a fluoroscopy technique. The case of a minimally displaced acetabular T-type fracture with a clear articular step in the weight-bearing area is presented. The percutaneous reduction and stabilization after intraoperative control of the reduction quality with the Siremobil Iso-C3D is demonstrated. Using the enhanced fluoroscopy technology with the ability to generate axial cuts and reconstructions comparable to CT clearly improves the reduction control also in acetabular surgery. Thus even displaced acetabular fractures can be reduced and stabilized percutaneously. Anatomic reconstruction of the joint remains the primary aim.

Acetabulum↗

PubMed2006

[Integrated navigation. Preclinical evaluation and initial clinical experience].

BACKGROUND: Computer navigation systems have increasingly become part of the surgical routine due to the improvements of intraoperative visualization procedures. Because of limited space in the operating room and insufficient workflow, the project of integrated navigation had been started. METHODS: As the first step, the navigation system VectorVision2 and the second-generation fluoroscopic C-arm system Orbic 3D were integrated into one common trolley. In an experimental study the integrated navigation system was used to drill 160 pedicle screws. Afterwards the system was clinically evaluated in 11 surgical procedures. RESULTS: During the whole experimental study the system could be used for all 160 drilling procedures without any technical faults, causing a failure rate of 4.2%. For clinical evaluation the integrated navigation system was used in seven patients with navigated dorsal spine instrumentation, in three cases sacroiliac screws were placed, and in one case supra-acetabular screw osteosynthesis was performed for an acetabular fracture. In all cases the positioning of the screws was correct and no system failure occurred. CONCLUSIONS: The combination of the navigation system and the C-arm system in one common trolley is a major improvement of the surgical workflow. In the experimental study and the clinical trials the system worked extremely reliably and with high precision.

Acetabulum↗

PubMed2006

[Low-grade-/high-grade-synovitis: synovitis-score as a gold standard?].

BACKGROUND: Synovectomy specimens represent important material submitted from the orthopedist to the pathologist. However, no consistent histopathological grading system for chronic synovitis has been established so far. PATIENTS AND METHODS: The three compartments of chronic synovitis (enlargement of lining cell layer, density of synovial stroma cells, leukocytic infiltrate) are graded semiquantitatively (from 0=absent to 3=strong), and the points for each compartment add up to the synovitis score: 0-1 = no synovitis, 2-4 = low-grade synovitis, 5-9 = high-grade synovitis. A total of 618 synovial specimens (resections n=559, biopsies n=59) from degenerative and inflammatory joint diseases were graded by two independent observers. RESULTS: Median synovitis scores when correlated to clinical diagnoses were: 1, control; 2, osteoarthritis and post-traumatic arthritis; 3, psoriatic arthritis; 5, reactive and rheumatoid arthritis. The differences between rheumatic and non-rheumatic diseases were significant (p<0.001). The correlation between the two observers was high (p<0.001). CONCLUSIONS: The proposed synovitis score enables stratification of chronic synovitis into low-grade (score 2-4) and high-grade (score >4), which is correlated to the nature of the disease (low-grade to non-rheumatic, high-grade to rheumatic), and it therefore contributes to the diagnosis of rheumatic and non-rheumatic joint diseases.

Adolescent↗

PubMed2006

Inhibition of human allergic T-helper type 2 immune responses by induced regulatory T cells requires the combination of interleukin-10-treated dendritic cells and transforming growth factor-beta for their induction.

BACKGROUND: In grass pollen-allergic individuals, T cell anergy can be induced by IL-10-treated dendritic cells (IL-10-DC) resulting in the suppression of T helper type 1 (Th1) as well as Th2 cells. This study was performed to analyse whether such IL-10-DC-treated T cells are able to act as regulatory T cells (Treg) suppressing the function of other T cells in the periphery. As transforming growth factor (TGF)-beta is also a potential inducer of Treg, we additionally analysed the inhibitory capacity of TGF-beta-treated T cells in this system. MATERIALS AND METHODS: Freshly isolated CD4+ or CD4+ CD25- T cells from grass pollen-allergic donors were stimulated with autologous mature monocyte-derived allergen-pulsed DC in the presence or absence of T cells previously cultured with IL-10-DC- and/or TGF-beta. RESULTS: Anergic T cells induced by allergen-pulsed IL-10-treated DC or allergen-pulsed DC and TGF-beta enhanced IL-10 production and strongly inhibited IFN-gamma production of freshly prepared peripheral CD4+ or CD4+ CD25- T cells while proliferation and Th2 cytokine production were only slightly reduced. The combination of allergen-pulsed IL-10-treated DC and TGF-beta had an additional effect leading to a significant suppression also of Th2 cytokine production and proliferation. Suppression was not antigen-specific and was mainly mediated by cell-to-cell contact and by the molecule-programmed death-1 and only partially by CTLA-4, TGF-beta and IL-10. CONCLUSION: These data demonstrate that regulatory T cells that also suppress Th2 cytokine production are induced by two signals: TGF-beta and IL-10-DC. This is of importance for the regulation of allergic immune responses and might be exploited for future therapeutic strategies for allergic diseases.

Allergens↗

PubMed2006

Comparative study using various methods for identification of Staphylococcus species in clinical specimens.

Coagulase-negative staphylococci (CNS) play a predominant role in nosocomial infections. Rapid, reliable identification of these organisms is essential for accurate diagnosis and prompt effective treatment of these infections. Quite recently, the VITEK 2 g-positive (gram-positive [GP]) identification card (bioMérieux) has been redesigned for greater accuracy in the identification of gram-positive cocci. We compared the BD Phoenix (Becton Dickinson) and VITEK 2 (bioMérieux) automated microbiology systems, using their respective update version cards, and the API ID32 STAPH test. The glyceraldehyde-3-phosphate dehydrogenase (gap) gene-based T-RFLP (terminal restriction fragment length polymorphism) method was used for verifying the results. In total, 86 clinical isolates of CNS and 27 reference strains were analyzed. The results show that for identification of CNS, the automated identification methods using the newest VITEK 2 and BD Phoenix identification cards are comparable. However, API ID32 STAPH revealed more correct results compared to both automated microbiology systems. Despite the increased performance of the phenotypic automated identification systems compared to the former versions, molecular methods, e.g., the gap-based T-RFLP method, still show superior accuracy in identifying Staphylococcus species other than Staphylococcus aureus.

Bacterial Typing Techniques↗

PubMed2006

Heterogeneity of methicillin-susceptible Staphylococcus aureus strains at a German University Hospital implicates the circulating-strain pool as a potential source of emerging methicillin-resistant S. aureus clones.

Recently, we demonstrated rapid dissemination of different methicillin-resistant Staphylococcus aureus (MRSA) clones at the Institute for Microbiology at the University of Magdeburg (B. Ghebremedhin, W. König, and B. König, Eur. J. Clin. Microbiol. Infect. Dis. 24:388-398, 2005). The majority of them harbored the readily transmissible mec cassette type IV. Thus, theoretically, methicillin-susceptible Staphylococcus aureus (MSSA) might capture the mecA gene from circulating MRSA, or MRSA strains might catch mobile toxin genes from MSSA. Therefore, we characterized MSSA strains circulating at the University Hospital in Magdeburg. Among a total of 84 MSSA strains under study, about 40% possessed the tst (toxic shock syndrome toxin) gene and up to four additional enterotoxin genes. tst-positive MSSA strains belonged to all known agr groups (I to IV) and to 14 different spa types (t008, t012, t015, t019, t024, t056, t065, t127, t133, t162, t271, t287, t399, and t400), and they were classified by multilocus sequence typing (MLST) as ST1, ST8, ST30, ST39, ST45, ST101, ST121, ST395, and ST426. In contrast, simultaneously circulating MRSA strains (n = 24) harbored in general two or three genes of the enterotoxin gene cluster, and the tst-positive MRSA isolates belonged to the well-known epidemic types ST22, ST45, and ST228 and were classified as spa types t001, t028, and t032. From our results, one may conclude that the pool of circulating MSSA strains is an important parameter with regard to the epidemiology of hospital- and community-acquired MRSA clones and their potential virulence.

Anti-Bacterial Agents↗

PubMed2005

[Evaluation of image quality of the Iso C3D image processor in comparison to computer tomography. Use in the pelvic area].

Intraoperative 3-D visualization using the Siremobil Iso C(3D) (Siemens, Erlangen, Germany) has been approved for use in spine and long bone surgery since its recent clinical launch. In preparation for the clinical use of the Siremobil Iso C(3D) in pelvic surgery, the aim of this study was to grade the quality of visualization in comparison with the gold standard of computer tomography in four therapy relevant pelvic regions in eight human cadavers, including SI screws to exemplify implants in the dorsal pelvic ring. Besides the influence of the body mass index and the interference of metal artefacts, visualization quality was evaluated in different pelvic regions (sacroiliac joint, acetabulum, femoral neck and anterior pelvic ring) using a score with five subgroups, rating the applicability of Siremobil Iso C(3D) in pelvic surgery. The grading of image quality in comparable standard projections was performed independently by three surgeons and three radiologists.Visualization quality appeared sufficient for both intraoperative and postoperative control in cases with a known preoperative diagnosis. There was no influence of body mass index found in any of the eight cadavers. Implants positioned in the dorsal pelvic ring reduced visualization quality, but sufficient estimation of bony structures was still possible. For primary diagnostics, computer tomography remains a clearly superior option due to better image quality. For intraoperative control of the reduction and positioning of implants in pelvic surgery, however, the additional intraoperative use of Siremobil Iso C(3D) is considered to offer clear advantages over current 2-D C-arm visualization tools.

Cadaver↗

PubMed2005

Heterogeneity of methicillin-resistant Staphylococcus aureus strains at a German university hospital during a 1-year period.

Heterogeneous methicillin-resistant Staphylococcus aureus (MRSA) strains, including community-acquired MRSA strains, have been observed in Central Europe. The purpose of this study was to characterize by molecular methods MRSA isolated during the period 2002-2003 at the Otto-von-Guericke University Hospital in Magdeburg, Germany, and at a nearby chronic care facility. Strains were analyzed for their resistance phenotype. Selected isolates were typed by multilocus sequence typing (MLST), by a multiplex polymerase chain reaction (PCR) for the staphylococcal cassette chromosome mec (SCCmec), by an allele-specific PCR for the staphylococcal accessory gene regulator (agr), and by PCR for the presence of toxin genes (sea-sej, tsst-1, hlgA, C, and B, lukE/D, and luk-pvl). Of the 2,731 S. aureus isolates studied, 199 (7.3%) were MRSA, with a prevalence of 21.6%, 19.6%, and 12% in the department of dermatology, the chronic care facility, and the intensive care units. Six different sequence types (ST247, ST228, ST22, ST22a, ST225, and ST45) were observed. Of these, ST22, ST22a, and ST45 dominated (>50%) in the department of dermatology and the chronic care facility. Strains with these sequence types were usually not resistant to gentamicin and were associated with agr group I, the SCCmec type IV element, and the presence of the sec and sed toxin genes. ST228 strains were found mainly in the intensive care units and had a broader resistance phenotype and were associated with agr group II and the SCCmec type I element. All luk-pvl-positive MRSA isolates (n=8) belonged to agr group I and were typed as ST22 or ST45 and contained the SCCmec type I (n=1), type III (n=1), or type IV (n=6) element. The main observations of this study are in concordance with previously reported findings showing dissemination of MRSA in Central Europe. Through the multitude of applied methods, the data from this study contribute to a more precise knowledge about the heterogeneity of MRSA in a clinical setting. Rapid dissemination of MRSA clones at a university hospital was demonstrated, indicating that dissemination may depend on the environmental conditions within the individual departments.

Bacterial Proteins↗

PubMed2005

[Comparison of radiation dose and image quality of Siremobil-IsoC(3D) with a 16-slice spiral CT for diagnosis and intervention in the human pelvic bone].

PURPOSE: To compare the image quality of 16-slice computed tomography with the image quality of Siremobil-IsoC (3D) of the pelvic region and to measure simultaneously the radiation dose before and after implantation of a sacroiliac screw (SI-screw) MATERIALS AND METHODS: The pelvic region of 8 human cadavers was examined in the Siremobil-IsoC (3D) at five different levels. We used a standard protocol for the 16-slice CT of the complete pelvic region before and after insertion of a pelvic screw, followed by stepwise reduction of the tube current to find the tube current that equalizes the image quality of both modalities. We controlled the image quality by judging important structures such as neuroforamen, nerves, sacroiliacal joint space, intervertebral space, osteophytes, iliopsoas muscle, acetabular surface, fovea centralis, hip joint and os pubis. The image quality was judged by three radiologists and three trauma surgeons using a ranking from 1 to 5. The dose was measured with an endorectally placed NOMEX Dosimeter, to obtain the gonadal dose. RESULTS: The medium score for all viewers of the Siremobil-IsoC (3D) examinations was between 3 and 4.3. The medium score for all CT-examinations with a tube current of 250 mA was between 1.3 and 2.2. The reduction of tube current down to 80 mA hardly influenced the marks for the analyzed structures. Under 80 mA, bony structures, even after implantation of a SI-screw, were still marked as good, but soft tissue differentiation was getting worse. For the examination of the pelvis, the average dose-length product for the IsoC (3D) was 41.2 mGy x cm. The medium dose-length product for CT was 389 mGy x cm for 250 mA, 125 mGy x cm for 80 mA and 82 mGy x cm for 60 mA. CONCLUSION: The Siremobil-IsoC (3D) is sufficient for therapeutic intraoperative purpose, but the image quality is not sufficient for diagnostic purpose. The higher dose-length product of a CT examination is justifiable because of a better overview, shorter examination time and qualitative superiority. An advantage of the Siremobil-IsoC (3D) is the intraoperative availability with acceptable 3D image quality compared to conventional fluoroscopy.

Bone Screws↗

PubMed2005

Automatic external defibrillation in a 6 year old.

A case is reported in which an automatic external defibrillator (AED) was used during the successful resuscitation of a 6 year old child in out-of-hospital cardiac arrest, despite the fact that these devices are not recommended in children under 8 years. The interpretation of resuscitation protocols is discussed and new developments in this area reported.

Cardiopulmonary Resuscitation↗

PubMed2004

New heterocyclic beta-sheet ligands with peptidic recognition elements.

A detailed and comprehensive overview is presented about the design, modeling, and synthesis, as well as spectroscopic characterization, of a new class of beta-sheet ligands. The characteristic feature of these compounds is a peptidic chimeric structure formed from a specific combination of aminopyrazolecarboxylic acids with naturally occurring alpha-amino acids. These hybrid peptides are designed with the aid of molecular modeling to exist mainly in an extended conformation. All their hydrogen bond donors and acceptors can be aligned at the bottom face in such a way that a perfect complementarity toward beta-sheets is obtained. Thus the aminopyrazoles impart rigidity and a highly efficient DAD sequence for the recognition of whole dipeptide fragments, whereas the natural alpha-amino acids are designed to mimick recognition sites in proteins, ultimately leading to sequence-selective protein recognition. The synthetic protocols either rely upon solution phase peptide coupling with a PMB protecting group strategy or solid-phase peptide coupling based on the Fmoc strategy, using the same protecting group. In solution, a key building block was prepared by catalytic reduction of a nitropyrazolecarboxylic acid precursor. Subsequently, it was (N-1)-protected with a PMB group, and elongated by HCTU- or T3P-assisted peptide coupling with dipeptide fragments, followed by PyClop-assisted coupling with another nitropyrazolecarboxylic acid building block. Final simultaneous deprotection of all PMB groups with hot TFA completed the high-yield protocol, which works racemization-free. After preparing a similar key building block with an Fmoc protection at N-3, we developed a strategy suitable for automated synthesis of larger hybrid ligands on a peptide synthesizer. Attachment of the first amino acid to a polystyrene resin over the Sieber amide linker is followed by an iterative sequence consisting of Fmoc deprotection with piperidine and subsequent coupling with natural alpha-amino acid via HATU/HOAt. High yields of free hybrid peptides are obtained after mild acidic cleavage from the resin, followed by deprotection of the PMB groups with hot TFA. The new aminopyrazole peptide hybrid compounds were characterized by various spectroscopic measurements including CD spectra, VT, and ROESY NMR experiments. All these accumulated data indicate the absence of any intramolecular hydrogen bonds and strongly support an extended conformation in solution, ideal for docking on to solvent-exposed beta-sheets in proteins. Initial results from aggregation tests of pathological proteins with these and related ligands look extremely promising.

Amino Acid Sequence↗

PubMed2004

[Accuracy of CT-based navitation of pedicle screws in the thoracic spine compared with conventional technique].

The goal of this study was to evaluate the accuracy of CT-based computer-assisted pedicle screw insertion in the thoracic spine in patients with fractures, metastases, and spondylodiscitis compared to a conventional technique. A total of 324 pedicle screws were inserted in the thoracic spines of 85 patients: 211 screws were placed using a CT-based optoelectronic navigation system assisted by an image intensifier and 113 screws were placed with a conventional technique. Screw positions were evaluated with postoperative CT scans by an independent radiologist. In the computer-assisted group, 174 (82.5%) screws were found completely within their pedicles compared with 77 (68.1%) correctly placed screws in the conventional group ( p<0.003). Despite use of the navigation system, 1.9% of the computer-assisted screws perforated the pedicle wall by more than 4 mm. The additional use of the image intensifier helped to identify the correct vertebral body and avoided cranial or caudal pedicle wall perforations.

Adolescent↗

PubMed2003

[CT and fluoroscopy based navigation in pelvic surgery].

Navigation procedures based upon CT data were introduced into spine surgery in 1994. Since then the method has been used in other areas, such as joint replacement, reconstructive surgery and tumor surgery, because of its high precision and reduced radiation exposure. The original CT-based spine module can be adapted for pelvic surgery with the prerequisite, that the positioning of the fragments is identical in CT and at operation; otherwise, a new data set has to be acquired. The experience with CT-based navigation in pelvic surgery will be explained in the context of five percutaneous screw fixations and three tumor resections. The technique will be described. The fluoroscopy-based navigation has been used in trauma surgery since the late 1990 s. Since than the method has gained wide acceptance in the field of joint replacement and reconstructive surgery as well. Between June 2000 and December 2002 we performed 36 percutaneous screw fixations in the pelvis with postoperative X-ray and CT control. Thirty five of the 36 screws were placed correctly. In one screw an anterior cortex perforation of the sacrum was seen on CT, but without neurological consequences. Based upon our clinical experience we believe that CT-based navigation is indicated in screw fixations for minimally displaced pelvic injuries or dysplasia and, with increasing importance, in tumor surgery. Fluoroscopy based navigation with adequate image quality is the method of choice for SI screw fixations in traumatic or degenerative instabilities, especially if an update of the images is needed.

Bone Neoplasms↗

PubMed2003

Influenza B pneumonia with Staphylococcus aureus superinfection associated with parvovirus B19 and concomitant agranulocytosis.

An 11-year-old patient with anamnestic fever for 3 days and signs of upper respiratory tract infection underwent fulminant Staphylococcus aureus pneumonia with concomitant agranulocytosis. From autopsia influenza B virus and parvovirus B19 were detected by nucleic acid amplification technique (NAT). Specific IgG but no IgM points to preexisting parvovirus B19 infection. Whether in this case agranulocytosis can be interpreted as early manifestation of reactivated parvovirus B19 infection is under discussion. Therefore, parvovirus B19 could have provoked a foudroyant course of influenza B pneumonia which was superinfected with S. aureus.

Agranulocytosis↗

PubMed2003

Tinea barbae caused by a zoophilic strain of Trichophyton interdigitale.

A deep absceding infection is reported of the inframandibular part of the face of a 22-year-old male student due to a zoophilic strain of Trichophyton interdigitale. The fungus was probably acquired from the cat of the patient. Initial therapy by a general practitioner was with topical glucocorticoids and oral antihistaminica. The patient developed a severe phlegmoneous inflammation of the bearded part of the face. Later, the patient was successfully treated by a combination of itraconazole and fluconazole. Identification of the species was confirmed by light and scanning microscopy as well as sequence analysis of the internal transcribed spacer region of the ribosomal DNA.

Adult↗

PubMed2003

Higher heart rate of laboratory mice housed individually vs in pairs.

Many studies have shown that housing mice individually over a long period significantly alters their physiology, but in most cases measurement has required human interference and restraint for sampling. Using a radio-telemetry system with implantable transmitters, we recorded heart rate (HR), motor activity (ACT) and body temperature (BT) of freely moving male mice (NMRI) housed either individually or in pairs with an ovarectomized female. Data for each parameter were collected at 5 min intervals for two consecutive 24 h periods. Even after several weeks of habituation to the social conditions, HR was increased in mice housed individually compared with mice housed in pairs, although their measured ACT did not differ. Additionally, BT tended to be reduced in individually-housed mice. When the data were analysed according to different ACT levels, HR was increased in individually-housed mice during phases of low and high, but not intermediate, motor activity. Furthermore, individually-housed mice had more, but shorter, resting bouts, indicating disruption of the normal circadian sleep pattern. Enhanced HR in individually-housed mice does not necessarily indicate stress, but might be an important physiological indicator of discomfort. The fact that individual housing alters basic physiological parameters in laboratory mice highlights the need to control for housing-dependent variation, especially in experiments that are sensitive to changes in these parameters.

Animals↗

PubMed2003

[Structure and clinical implications of the coronary horn stratification with special consideration of horn maturation, aging and decay processes in the equine hoof].

The three superimposing strata of the coronet and the ageing process and decay of the hoof horn were studied in 56 fore hooves of 28 domestic horses of different age and sex. Except for horn clefts at the weight bearing margin, their hooves did not show any signs of pathological changes. Their hooves did not show any signs of pathological changes. The investigation comprised the analysis of the structure and the mechanical-physical measurement of horn hardness. The own results showed that the functional and clinical importance of the three strata of the coronet concerns the absorption and distribution of the horizontal and vertical pressure and the resilient-elastical fixatia of the suspensory apparatus of the coffin bone to the inner spongiforme Stratum medium. Disruptive pathological changes may spread out between the different horn layers which sometimes leads to the phenomenon of the "Hollow Wall". The hard and stable coronet is composed of tubular and intertubular horn. Distal of the crest of the coffin bone the horn hardness decreases and clefts are visible which are interpreted as ageing processes. The medullar horn decays much faster in certain regions, thus enabling ascending infections especially in the white line area, causing "White Line Disease". Under consideration of the references the own results proved, that regular and professional trimming of the hoof can prevent these diseases and improves the pododermal blood circulation and the orthokeratotic cornification. By improving the stable hygiene and adequate nutritional supply with minerals and vitamins these measures can be supported.

Aging↗