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  • 1
    Electronic Resource
    Electronic Resource
    Dietary vitamin E does not protect from endotoxin-induced hepatic microvascular dysfunction (1997)
    Springer
    Cellular and molecular life sciences 53 (1997), S. 294-302 
    Details
    ISSN: 1420-9071
    Keywords: Key words. Vitamin E; α-tocopherol acetate; scavenger; reactive oxygen species; leukocyte-endothelial cell interaction; Kupffer cell; microcirculation; liver.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Starting from the concept that lipopolysaccharide (LPS)-associated hepatotoxicity involves the action of reactive oxygen species, the present study was conducted to test whether vitamin E, a lipophilic antioxidant, prevents LPS-induced hepatic microvascular dysfunction and liver injury. Fifty-two rats were divided into three groups and fed diets containing 0 (n=16), 75 (n=18) or 8000 mg (n=18) α-tocopherol acetate/kg food for four weeks. At 1 h and 6 h after intravenous LPS-exposure (10 mg/kg E. coli LPS) hepatic microvascular response and liver injury were assessed by the analysis of Kupffer cell phagocytic activity, leukocyte-endothelial cell interaction and nutritive sinusoidal perfusion (intravital fluorescence epi- illumination technique) as well as bile flow, serum liver enzyme activities and tissue histomorphology. In animals fed with 75 mg vitamin E/kg (standard diet), LPS caused hepatic Kupffer cell activation (increased phagocytic activity) and hepatic microvascular leukocyte activation, with stasis in sinusoids and adherence in postsinusoidal venules (1 h) followed by leukocytic infiltration into tissue (6 h) and progredient sinusoidal perfusion failure (6 h). Hepatic microvascular injury was accompanied by reduced bile flow and enhanced liver enzyme release. Vitamin E-enriched diet (8000 mg/kg) and even vitamin E-deficient diet did not significantly affect LPS-induced hepatic microvascular cell activation and perfusion failure. Thus, we conclude, that vitamin E is not effective to protect from endotoxin-induced hepatic microvascular dysfunction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00000607
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of cyclosporine A on the process of vascularization of freely transplanted islets of Langerhans (1999)
    Springer
    Journal of molecular medicine 77 (1999), S. 111-114 
    Details
    ISSN: 1432-1440
    Keywords: Key words Islet transplantation ; Angiogenesis ; Vascularization ; Cyclosporine A ; Hamster ; Intravital microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied in vivo the effect of cyclosporine A (CsA) on both pancreatic islet vascularization and microvascular perfusion using intravital fluorescence microscopy and the dorsal skinfold chamber model in Syrian golden hamsters. Syngeneic transplantation was performed in order to exclude allograft- or xenograft-induced microvascular alterations. To study the effect of CsA on islet angiogenesis and vascularization, animals received 20 mg/kg CsA daily from day 0 until day 14 after transplantation (group A). To study toxic effects of CsA on islet microcirculation, the grafts were allowed to vascularize without immunosuppression, and 20 mg/kg CsA was given daily from day 10 until day 20 after transplantation (group B). Quantitative analysis of the process of islet vascularization in group A revealed a functional capillary density (FCD) of 515.6±72.7 cm–1 at day 6 after transplantation without further increase until day 14 (504.3±16.7 cm–1). Islet transplants which were not treated with CsA during the process of angiogenesis/vascularization (group B) demonstrated a slightly but significantly (P〈0.05) higher FCD (604.7±42.5 cm–1) at day 14 after transplantation, indicating slightly improved vascularization when compared to transplants of group A. Additional CsA treatment of these islet grafts until day 20 did not induce derangements of microvascular perfusion (601.2±67.0 cm–1), indicating that the immunosuppressive, drug has no toxic/detrimental effects on the transplants nutritional blood supply. We conclude that CsA only slightly alters the process of final vascularization of freely transplanted islets, and does not deteriorate nutritive perfusion of completely vascularized grafts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001090050314
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  • 3
    Electronic Resource
    Electronic Resource
    Cell surface and nuclear changes during TNF-α-induced apoptosis in WEHI 164 murine fibrosarcoma cells (1998)
    Springer
    Virchows Archiv 433 (1998), S. 75-83 
    Details
    ISSN: 1432-2307
    Keywords: Key words Apoptosis ; Cell surface ; Cell nucleus ; Blebs ; TNF-α ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Tumour necrosis factor (TNF)-α-induced apoptosis is associated with several nuclear and cell surface alterations, in particular with the condensation of chromatin and the fragmentation of the cell nucleus, formation of blebs on the cell surface and breakdown of the plasma membrane. However, there is little information about the relationship between the cell surface alterations and the nuclear changes during apoptosis. To study this, cultured WEHI cells were exposed to TNF-α over different time periods. The cytological changes were studied using a correlative approach, which allowed observation of the same cell consecutively under light, scanning and transmission electron microscopy. The earliest sign of cell alteration was a reduction of the number of microvilli after 15 min of TNF-α exposure. This reaction was reversible (reappearance of microvilli) and took place during the first hour, in which neither nuclear alterations nor plasma membrane breakdown were observed. The changes in the nucleus began with condensation of chromatin after approximately 1 h of TNF-α-exposure. After 4–5 h the microvilli disappeared again, particularly in areas where the formation of blebs (blebbing) was observed. Strikingly, cell surface alterations (bleb formation) were detected only in those cells that presented with condensed chromatin, and not in cells with a normal chromatin pattern, proving at least a close correlation between nuclear and cell surface changes during the process of apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004280050219
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  • 4
    Electronic Resource
    Electronic Resource
    Systemic inflammatory response syndrome (SIRS) and sepsis in surgical patients (1996)
    Springer
    Intensive care medicine 22 (1996), S. 616-617 
    Details
    ISSN: 1432-1238
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01708116
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  • 5
    Electronic Resource
    Electronic Resource
    Effectiveness of a hands-on training course for laparoscopic spine surgery in a porcine model (1999)
    Springer
    Surgical endoscopy and other interventional techniques 13 (1999), S. 118-122 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Hands-on training course — Minimal invasive surgery — Laparoscopic anterior interbody spine fusion — Porcine model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Although it is widely proposed that surgeons, before introducing a novel laparoscopic technique in man, should practice in an appropriate animal model for acquisition of the necessary technical skills, the effectiveness of those hands-on training courses are rarely documented. Methods: In 1995 we have organized eight hands-on training courses for laparoscopic anterior interbody spine fusion in an in vivo porcine model. A total of 72 colleagues from 50 different centers of 12 countries participated, including orthopedic, trauma, visceral, neuro-, and vascular surgeons. Quality and effectiveness of the course were evaluated by a questionnaire after a 1.5- to 2.5-year period. Results: During this time, 42.2% of the participating centers had applied the new technique successfully in man. Centers which participated in the course with a team that included a skilled laparoscopic surgeon and an orthopedic or trauma surgeon introduced the technique more frequently to clinical practice (57.9%) than those represented by only one participant (30.8%). Moreover, there was a tendency toward a more frequent introduction of the technique to clinical practice in centers associated with university hospitals (57.1% vs. 29.2%), indicating the requirement of a particular infrastructure for this complex interdisciplinary procedure. Almost all participants (98.3%) agreed that for novel surgical techniques requiring advanced technical skills, there should first be training in a large animal model before the technique is applied in man. Conclusions: Complex laparoscopic procedures (i.e., laparoscopic spine surgery) can be successfully learned by in vivo hands-on training courses. We propose that for refinements and modifications of the technique (e.g., the lumboscopic approach), there should also first be training in a large animal model before these are applied in man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900918
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  • 6
    Electronic Resource
    Electronic Resource
    Experimental development and validation of a technique for lumboendoscopic anterior fusion of lumbar spine fracturesrid="" (2000)
    Springer
    Surgical endoscopy and other interventional techniques 14 (2000), S. 844 -848 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Anterior spine fusion — Lumboendoscopic spine surgery — Minimally invasive spine surgery — Pigs — Retroperitoneoscopy — Spine fractures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Background: Using a porcine model, this study describes the feasibility of a lumboendoscopically guided approach to the lumbar spine for anterior interbody fusion, and compares the results with that of the open procedure. The objectives of this study were to develop a minimally invasive approach to the lumbar spine for anterior fusion in pigs, and to test the validity and safety of the procedure in this porcine model. Besides posterior stabilization, considerable number of thoracolumbar spine (Th12–L5) fractures require intervention for anterior fusion to prevent loss of height of the injured segment and kyphotic deformation. Because anterior fusion needs major surgery (thoracophrenolumbotomy for Th12–L1), which is associated with high morbidity, this study aimed to develop a less traumatic minimally invasive approach. Methods: Six pigs under balanced anesthesia were used to study the feasibility of the lumboendoscopic approach for bisegmental fusion (iliac crest bone block and dynamic compression plate) from Th15 to L6. In an additional six animals, lumboendoscopic fusion was performed at the level of diaphragm insertion (Th14–Th16), representing Th12–L1 in patients. For comparative analysis, six animals undergoing open thoracophrenolumbotomy and anterior Th14–Th16 fusion served as control subjects. Results: Endoscopic anterior fusion could be successfully performed at all levels of the thoracolumbar spine without major complications. In three cases, unintended opening of the peritoneal cavity was observed, however, without the operative procedure being affected. Comparative analysis revealed a significantly longer p 〈 0.01 operation time (126 ± 6.5 min) and increased femoral vein pressure (11.3 ± 0.7 mmHg) in animals undergoing endoscopic surgery (open procedure, 76.0 ± 11.6 min and 5.2 ± 0.5 mmHg). However, the microvascular blood supply (perfusion) to the distal extremities, as assessed by laser Doppler flowmetry, was not affected. Conclusions: Our study demonstrates that lumboendoscopic anterior spine fusion in pigs is feasible at all levels from Th14 to L6, and can be performed in an acceptable operation time without major complications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004640000221
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  • 7
    Electronic Resource
    Electronic Resource
    Cold preservation of the small intestine with the new Celsior-solution (1998)
    Springer
    Transplant international 11 (1998), S. 32-37 
    Details
    ISSN: 1432-2277
    Keywords: Key words Celsior ; preservation ; Small bowel ; preservation ; Preservation ; small bowel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the present study was to evaluate the potential of Celsior, a recently developed cardioplegic and heart storage solution, to protect the small bowel during ischemic storage. Small bowel segments were isolated from rats, flushed with either UW or Celsior solution, and cold-stored for 18 h at 4 °C in the respective solution. After ischemic storage, some preparations were freeze-clamped for analysis of tissue metabolites while other preparations were tested for structural and functional integrity by isolated perfusion in vitro using a previously validated model. After 18 h of ischemic storage no significant differences were seen between Celsior and UW with regard to the development of edema, energy charge, or creatine phosphate, but lactate accumulation was significantly reduced in the Celsior group, although glucose catabolism was not inhibited. Histological evaluation of the cold-stored organs showed no differences with regard to structural integrity between the two groups. Total vascular resistance upon reperfusion was significantly lower in the Celsior group (666 ± 126 vs 827 ± 88 MPa s m–3 *), as was the intestinal release of LDH (9.7 ± 4.4 vs 18.2 ± 4.6 U/l *). Carbohydrate absorption from the intestinal lumen amounted to venous effluent concentrations of 0.58 ± 0.24 vs 0.18 ± 0.15 mg% * of galactose in the Celsior and UW groups, respectively. Within the limits of this in vitro pilot study, Celsior provided better postischemic recovery of the small bowel than UW in terms of vascular perfusion characteristics, enzyme release, and carbohydrate absorption and may, thus, be considered a suitable alternative for intestinal organ preservation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050099
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  • 8
    Electronic Resource
    Electronic Resource
    Reliable noninvasive parameters for early detection of cardiopulmonary compromise induced by carbon dioxide thoracoretroperitoneum in minimally invasive thoracolumboendoscopic spine surgeryrid=""id=""Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), San Antonio, Texas, USA, 24–27 March, 1999 (2000)
    Springer
    Surgical endoscopy and other interventional techniques 14 (2000), S. 820 -824 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Anterior spine fusion — CO2 insufflation — ETCO2— Hypercapnia — Hypoxia — Minimally invasive surgery — Peak respiratory pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Using a novel endoscopic retroperitoneal approach for thoracolumbar anterior spine fusion, we examined the cardiopulmonary effects of the inevitably associated carbon dioxide (CO2) thoracoretroperitoneum and evaluated noninvasive parameters, which may provide early and adequate recognition of cardiopulmonary dysfunction. Methods: Under balanced anesthesia and paralysis, six pigs subjected to endoscopic CO2 thoracoretroperitoneal spine fusion underwent extensive pulmonary and hemodynamic online monitoring throughout the operative procedure. Open thoracophrenolumbotomy in six pigs served as a control procedure. Results: In contrast to unchanged cardiopulmonary parameters during open thoracolumbar spine surgery, CO2 thoracoretroperitoneum caused significant hypercapnia, hypoxia, and acidemia with concomitant tachycardia, pulmonary hypertension, and systemic hypotension. Ventilatory adjustment, CO2 evacuation, or both promptly reversed the cardiopulmonary effects. Noninvasively assessed end-tidal CO2, peak respiratory pressure, and heart rate were early clues for detecting the tension pneumothorax-like cardiopulmonary dysfunction, as indicated by a significant correlation with the invasively assessed pulmonary hemodynamic parameters and arterial blood gases. Conclusions: During endoscopic thoracolumbar spine fusion, CO2 thoracoretroperitoneum induces cardiopulmonary dysfunction, which, however, can be detected reliably by changes in end-tidal CO2, peak respiratory pressure, and heart rate, and which can be corrected immediately by appropriate ventilatory adjustments. Therefore, endoscopic CO2 thoracoretroperitoneal spine fusion might not necessarily require extraordinarily extensive and invasive monitoring of systemic and pulmonary hemodynamics, but ventilatory adjustment and intrathoracic pressure evacuation should be readily available to reexpand the lung, and to facilitate rapid normalization of hemodynamic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004640010066
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  • 9
    Electronic Resource
    Electronic Resource
    Exocrine, but not endocrine, tissue is susceptible to microvascular ischemia/reperfusion injury following pancreas transplantation in the rat (1999)
    Springer
    Transplant international 12 (1999), S. 50-55 
    Details
    ISSN: 1432-2277
    Keywords: Key words pancreas transplantation ; rat ; exocrine tissue ; reperfusion ; Endocrine tissue ; reperfusion ; Microcirculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract While post-transplant pancreatitis is still a frequently occurring complication of whole pancreas transplantation, dysfunction of the endocrine tissue is rarely observed. Given that microcirculatory disorders play a major role in the pathogenesis of pancreatitis, we hypothesized a dissociation of endocrine and exocrine microvascular control in pancreas transplantation (cold ischemia-reperfusion) and studied this dissociation quantitatively, analyzing the pancreatic microcirculation after heterotopic isogeneic pancreaticoduodenal transplantation in rats by means of fluorescence microscopy. Functional capillary density (FCD) of both exocrine and endocrine tissue of pancreatic grafts after 1 h of cold storage in HTK solution did not differ when compared to sham-operated, time-matched controls. Intermittent capillary perfusion, which is absent under sham control conditions and which is proposed to be operative as a compensatory mechanism to counteract malperfusion, was observed in 52 % of the exocrine, but in only 8 % of the endocrine, tissue studied (p 〈 0.05). In contrast, cold storage of pancreatic grafts for 6 h in HTK resulted in a complete loss of intermittent capillary perfusion in exocrine tissue and, consequently, marked exocrine perfusion failure (decrease in FCD), while FCD of pancreatic endocrine tissue was preserved without any significant change in the incidence of intermittent capillary perfusion. Thus, our results indicate a higher susceptibility of the exocrine pancreas to cold ischemia/reperfusion events that is associated with significant alterations in nutritive perfusion and, thus, with limitations of the oxygen supply to the tissue. This may lead to inflammatory tissue reactions in the clinical setting of pancreas transplantation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050184
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  • 10
    Electronic Resource
    Electronic Resource
    Heparin and phentolamine combined, rather than heparin alone, improves hepatic microvascular procurement in a non-heart-beating donor rat-model (2000)
    Springer
    Transplant international 13 (2000), S. 225-229 
    Details
    ISSN: 1432-2277
    Keywords: Key words Non-heart-beating donors ; Liver ; Microvascular preservation ; Heparin ; Phentolamine ; Warm ischemia time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Improvement of organ procurement from non-heart-beating donors (NHBDs) could increase the donor organ pool for liver transplantation. Whether anti-coagulative and anti-vasospastic substances can improve hepatic microvascular preservation from NHBDs is unknown. In donor rats which were pretreated with either heparin (n = 6) or heparin combined with phentolamine (n = 7) 10 min prior to cardiac arrest, the extent and homogeneity of hepatic microvascular reperfusion was assessed at the end of a 60-min period of cardiac arrest using in situ fluorescence microscopy. Non-pretreated animals with cardiac arrest for 60 min served as controls (n = 6). In the non-treated NHBDs, arterial gravity perfusion of 100 cm H2O with HTK-solution led to a hepatic acinar reperfusion of only ∼ 22 % with a remarkably diminished sinusoidal density. Application of heparin prior to cardiac arrest resulted in a two-fold, but insignificant increase of acinar perfusion and sinusoidal density with a still considerable heterogeneity of both parameters. Livers of NHBDs that additionally received phentolamine exhibited significantly increased values of both acinar perfusion and sinusoidal density. Phentolamine was found to reduce heterogeneity of organ microperfusion. Thus, our results indicate that the combined application of heparin and phentolamine is a useful additive for optimizing the quality of organs harvested from NHBDs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050691
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