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  • 1
    Electronic Resource
    Electronic Resource
    Transgene expression in human epidermal keratinocytes: cell cycle arrest of productively transfected cells (2000)
    Copenhagen : Munksgaard International Publishers
    Experimental dermatology 9 (2000), S. 0 
    Details
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: We have analysed the consequences of liposome mediated gene transfer into human primary epidermal keratinocytes and compared non-Epstein–Barr Virus (EBV) and EBV based expression vectors that carry the genes encoding human Growth Hormone (hGH) or Enhanced Green Fluorescent Protein (EGFP). Different kinetics between the non-EBV and EBV based vectors were revealed upon subcultivation of hGH transfected keratinocytes. The keratinocytes transfected with non-EBV based vector showed a rapid reduction in hGH production. Although the EBV based vector resulted in more stable expression, this was also reduced over time. Chromatin inactivation by deacetylation was investigated by treatment with sodium butyrate and found not to be the reason for the decreasing expression. Keratinocytes divided into subpopulations enriched for either stem cells or transit amplifying cells, based on β1-integrin expression and function, do not differ significantly with respect to susceptibility to productive transfection. However, when the keratinocytes were transfected with the EGFP gene and sorted live by FACS into EGFP negative and positive populations, only the negative cells were capable of forming significant numbers of colonies. This is consistent with the observation that the ability to incorporate BrdU was dramatically reduced in the EGFP expressing population within 24–48 h post transfection indicating an almost complete cell cycle arrest. p53 levels were unaffected by the procedures, and the keratinocyte cell line HaCat, mutated in both p53 alleles, also shows a marked reduction in clonogenic potency upon transfection. There was a slight increase of TUNEL positive apoptotic nuclei in the positive population at early time points. However, the apoptotic index was still very low. When we measured the frequency of involucrin expressing cells, we found an increase in the productively transfected population over time indicating an initiation of terminal differentiation. In contrast to the transfected cultures, keratinocytes that were transduced using a retroviral vector showed no decrease in colony forming efficiency. In conclusion we find that transgene expressing cells from transfected cultures of epidermal keratinocytes undergo cell cycle arrest and initiate terminal differentiation by mechanisms which are independent of p53 levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0625.2000.009004298.x
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  • 2
    Electronic Resource
    Electronic Resource
    Androgen Inhibits, While Oestrogen Enhances, Restraint-Induced Activation of Neuropeptide Neurones in the Paraventricular Nucleus of the Hypothalamus (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 16 (2004), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The hormonal response to stress is enhanced by oestrogen but inhibited by androgens. To determine underlying changes in activity of neuropeptide neurones in the paraventricular nucleus of the hypothalamus (PVN), we examined the effect of oestrogen and androgen treatment on restraint-induced c-fos mRNA, corticotropin-releasing hormone (CRH) heteronuclear RNA, and arginine vasopressin hnRNA expression in the PVN. Male rats were gonadectomized and injected with oestradiol benzoate (EB) or dihydrotestosterone propionate (DHTP; s.c., daily for 4 days). Rats were stressed by restraint for 10 min or 30 min before killing. Other rats were stressed for 30 min and then returned to their home cage for 20 min before killing. Corticosterone and adrenocorticotropic hormone responses to restraint stress were significantly greater in EB-treated rats and lower in DHTP-treated rats at the 30-min timepoint compared to controls. c-fos mRNA increases following stress were augmented by EB but inhibited by DHTP. CRH hnRNA expression increased significantly in the PVN in response to restraint stress, and this increase was augmented by EB treatment, but decreased by DHTP treatment. Vasopressin hnRNA expression was also increased in response to stress, and this increase was attenuated by DHTP. These findings indicate that gonadal hormones influence the reactivity of the hypothalamic-pituitary adrenal axis to stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0953-8194.2004.01167.x
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  • 3
    Electronic Resource
    Electronic Resource
    Immediate control of life-threatening digoxin intoxication in a child by use of digoxin-specific antibody fragments (Fab) (2003)
    Oxford, UK : Blackwell Science Ltd
    Pediatric anesthesia 13 (2003), S. 0 
    Details
    ISSN: 1460-9592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary Digoxin-immune antibody fragments (Fab) for treatment of digitalis intoxication was introduced in 1976. Many reports have been published concerning this therapy for children, but few have focused on its immediate reversal of cardiac as well as extracardiac life-threatening manifestations of digoxin toxicity. We present a case of life-threatening digitalis intoxication in a child with postoperative renal insufficiency, after a Sennings procedure for transposition of the great arteries. Digoxin administration according to the nationally recommended dosage and intervals unexpectedly resulted in serum levels in the toxic range. Severe cardiac arrhythmias, haemodynamic instability and a rapid-increasing serum potassium level resulted. This report demonstrates how administration of Fab according to the manufacturer's dosage recommendation reversed the tachyarrhythmia immediately and re-established a normal level of serum potassium within minutes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2003.01068.x
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  • 4
    Electronic Resource
    Electronic Resource
    Computer-assisted spine surgery (2000)
    Springer
    European spine journal 9 (2000), S. S057 
    Details
    ISSN: 1432-0932
    Keywords: Key words Image-guided spine ¶surgery ; Computer navigation ; Cervical spine ; Thoracic spine ; Lumbar spine ; Iliosacral joint ; Pedicle screws
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Computer assistance has been shown to improve significantly the accuracy and safety of pedicle screw insertion under clinical conditions. The technique of image-guided navigation is described in this article, based on the authors’ clinical experience of over 4 years. The value of navigation systems for preoperative planning is discussed. Clinical results of the application of this new method in the cervical, thoracic, and lumbosacral spine as well as the iliosacral joints are presented by means of the authors’ own studies and reports from the literature. Pros and cons of computer guidance are discussed. The authors predict computer navigation will be used in percutaneous and minimally invasive procedures in the near future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00010023
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  • 5
    Electronic Resource
    Electronic Resource
    Accuracy of pedicle screw insertion with and without computer assistance: a randomised controlled clinical study in 100 consecutive patients (2000)
    Springer
    European spine journal 9 (2000), S. 235-240 
    Details
    ISSN: 1432-0932
    Keywords: Key words Spine surgery ; Computer-assisted surgery ; Pedicle screws ; Image guidance ; Randomised controlled trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed a randomised controlled study to assess the accuracy of computer-assisted pedicle screw insertion versus conventional screw placement under clinical conditions. One hundred patients scheduled for posterior thoracolumbar or lumbosacral pedicle screw instrumentation were randomised into two groups, either for conventional pedicle screw placement or computer-assisted screw application using an optoelectronic navigation system. From the computer-assisted group, nine patients were excluded: one because of an inadequate preoperative computed tomography study, seven because of problems with the specific instruments or the computer system, and one because of an intraoperative anesthesiological complication. Thus, there were 50 patients in the conventional group and 41 in the computer-assisted group, and the number of screws inserted was 277 and 219, respectively. There was no statistical difference between the groups concerning age, gender, diagnosis, type of operation performed, mean operating time, blood loss, or number of screws inserted. The time taken for screw insertion was significantly longer in the computer-assisted group. Postoperatively, screw positions were assessed by an independent radiologist using a sophisticated CT imaging protocol. The pedicle perforation rate was 13.4% in the conventional group and 4.6% in the computer-assisted group (P = 0.006). Pedicle perforations of more than 4 mm were found in 1.4% (4/277) of the screw insertions in the conventional group, and none in the computer-assisted group. Complications not related to pedicle screws were two L5 nerve root lesions, one end plate fracture, one major intraoperative bleeding and one postoperative death in the conventional group, and one deep infection in the computer-assisted group. In conclusion, pedicular screws were inserted more accurately with image-guided computer navigation than with conventional methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005860000146
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  • 6
    Electronic Resource
    Electronic Resource
    Biomechanics of stand-alone cages and cages in combination with posterior fixation: a literature review (2000)
    Springer
    European spine journal 9 (2000), S. S095 
    Details
    ISSN: 1432-0932
    Keywords: Key words Interbody cage ; Biomechanics ; Implant ; Stabilization ; Strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Interbody cages in the lumbar spine have met with mixed success in clinical studies. This has led many investigators to supplement cages with posterior instrumentation. The objective of this literature review is to address the mechanics of interbody cage fixation in the lumbar spine with respect to three-dimensional stabilization and the strength of the cage-vertebra interface. The effect of supplementary posterior fixation is reviewed. Only three-dimensional stabilization evaluations in human cadaveric models are included. These studies involve the application of different loads to the spine and the measurement of vertebral motion in flexion-extension, axial rotation, and lateral bending. There are no published studies which detected any differences between different cage designs. However, it does seem that cages inserted from an anterior direction provide better stabilization to the spine than those inserted from a posterior direction. In general, anterior cages stabilize better than posterior cages in axial rotation and lateral bending. Cages from both directions stabilized well in flexion, but not in extension. Supplementary posterior fixation with pedicle or translaminar screws substantially improves the stabilization in all directions. The strength of the cage-vertebra interface from studies using human cadaveric specimens is also reviewed. The axial compressive strength of this interface is highly dependent upon vertebral body bone density. Other factors such as preservation of the subchondral bony end-plate and cage design are clearly less important in the compressive strength. Supplementary posterior instrumentation does not enhance substantially the interface strength in axial compression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00010028
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  • 7
    Electronic Resource
    Electronic Resource
    A new approach to computer-aided spine surgery: fluoroscopy-based surgical navigation (2000)
    Springer
    European spine journal 9 (2000), S. S078 
    Details
    ISSN: 1432-0932
    Keywords: Key words Spine ; Implant ; Pedicle screws ; Navigation ; Fluoroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A new computer-based navigation system for spinal surgery has been designed. This was achieved by combining intraoperative fluoroscopy-based imaging using conventional C-arm technology with freehand surgical navigation principles. Modules were developed to automate digital X-ray image registration. This is in contrast to existing computed tomography- (CT) based spinal navigation systems, which require a vertebra-based registration procedure. Cross-referencing of the image intensifier with the surgical object allows the real-time image-interactive navigation of surgical tools based on one single registered X-ray image, with no further image updates. Furthermore, the system allows the acquisition and real-time use of multiple registered images, which provides an advanced multi-directional control (pseudo 3D) during surgical action. Stereotactic instruments and graphical user interfaces for image-interactive transpedicular screw insertion have been developed. A detailed validation of the system was performed in the laboratory setting and throughout an early clinical trial including eight patients in two spine centers. Based on the resulting data, the new technique promises improved accuracy and safety in open and percutaneous spinal surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00010026
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  • 8
    Electronic Resource
    Electronic Resource
    Clustering by Adaptive Local Search with Multiple Search Operators (2000)
    Springer
    Pattern analysis and applications 3 (2000), S. 348-357 
    Details
    ISSN: 1433-755X
    Keywords: Keywords:Adaptation; Clustering; GLA; Local Search; Stochastic complexity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract: Local Search (LS) has proven to be an efficient optimisation technique in clustering applications and in the minimisation of stochastic complexity of a data set. In the present paper, we propose two ways of organising LS in these contexts, the Multi-operator Local Search (MOLS) and the Adaptive Multi-Operator Local Search (AMOLS), and compare their performance to single operator (random swap) LS method and repeated GLA (Generalised Lloyd Algorithm). Both of the proposed methods use several different LS operators to solve the problem. MOLS applies the operators cyclically in the same order, whereas AMOLS adapts itself to favour the operators which manage to improve the result more frequently. We use a large database of binary vectors representing strains of bacteria belonging to the family Enterobacteriaceae and a binary image as our test materials. The new techniques turn out to be very promising in these tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100440070006
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  • 9
    Electronic Resource
    Electronic Resource
    Computerunterstützte Wirbelsäulenchirurgie (2000)
    Springer
    Der Orthopäde 29 (2000), S. 658-669 
    Details
    ISSN: 1433-0431
    Keywords: Schlüsselwörter Computerunterstützte Chirurgie •¶Pedikelschrauben • Wirbelsäulenchirurgie • Bildinteraktive Navigation ; Keywords Computer-assisted surgery • Image guidance • Spine surgery • Pedicle screws •¶Computer navigation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Computer-assisted techniques were introduced in spine surgery in the 1990s to improve accuracy and safety of operative procedures. Several reports on clinical results of computer-aided screw insertion in the cervical, thoracic, and lumbar spine as well as the sacro-iliac joints are available. They show a significant decrease of screw malplacement rates as compared to conventional insertion techniques. The quality of preoperative planning of spinal procedures has improved markedly by using computer navigation systems. Drawbacks, reliability problems, and safety issues of computer navigation are discussed. In the near future, the use of computer guidance for minimally invasive and percutaneous spine procedures is expected.
    Notes: Zusammenfassung Computerunterstützte Operationsverfahren sind in den 90 er Jahren in die Wirbelsäulenchirurgie eingeführt worden, um Präzision und Sicherheit zu erhöhen. Erste klinische Erfahrungsberichte verschiedener Arbeitsgruppen über die Anwendung passiver stereotaktischer Navigationssysteme zur Schraubeninsertion an der Halswirbel- (HWS), Brustwirbel- (BWS) und Lendenwirbelsäule (LWS) sowie im Bereich der Iliosakralgelenke liegen vor. Sie zeigen eine signifikante Senkung der Fehlplatzierungsrate im Vergleich zu herkömmlichen Insertionstechniken. Die Qualität der präoperativen Planung von Wirbelsäulenoperationen wird durch die Navigationssysteme entscheidend verbessert. Nachteile, Grenzen, Zuverlässigkeit und Sicherheitsprobleme der Computernavigation werden diskutiert. Die Anwendung dieser Techniken für minimal-invasive und perkutane Eingriffe an der Wirbelsäule wird in naher Zukunft erwartet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/
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