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Wiemann S, Bott A, Keklikoglou I, Giacomelli C, Balwierz A, Uhlmann S, Mannsperger H, Korf U, Breunig C. 53: miRNA-protein interaction networks in cancer. Eur J Cancer 2014. [DOI: 10.1016/s0959-8049(14)50053-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kraan M, Uhlmann S, Steenbergen J, Van Helmond ATM, Van Hoof L. The optimal process of self-sampling in fisheries: lessons learned in the Netherlands. J Fish Biol 2013; 83:963-973. [PMID: 24090557 DOI: 10.1111/jfb.12192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
At-sea sampling of commercial fishery catches by observers is a relatively expensive exercise. The fact that an observer has to stay on-board for the duration of the trip results in clustered samples and effectively small sample sizes, whereas the aim is to make inferences regarding several trips from an entire fleet. From this perspective, sampling by fishermen themselves (self-sampling) is an attractive alternative, because a larger number of trips can be sampled at lower cost. Self-sampling should not be used too casually, however, as there are often issues of data-acceptance related to it. This article shows that these issues are not easily dealt with in a statistical manner. Improvements might be made if self-sampling is understood as a form of cooperative research. Cooperative research has a number of dilemmas and benefits associated with it. This article suggests that if the guidelines for cooperative research are taken into account, the benefits are more likely to materialize. Secondly, acknowledging the dilemmas, and consciously dealing with them might lay the basis to trust-building, which is an essential element in the acceptance of data derived from self-sampling programmes.
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Affiliation(s)
- M Kraan
- IMARES, Haringkade 1, 1976, CP IJmuiden, the Netherlands
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Sahin O, Uhlmann S, Zhang J, Schwaeger A, Mannsperger H, Burmester S, Ward A, Korf U, Wiemann S. 432 MicroRNAs in the miR-200 family differentially regulate cell cycle progression and EGF-driven invasion by modulating p27/Kip1, CDK6 and PLC-gamma1 in breast cancer. EJC Suppl 2010. [DOI: 10.1016/s1359-6349(10)71233-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Uhlmann S, Zhang JD, Schwäger A, Mannsperger H, Riazalhosseini Y, Burmester S, Ward A, Korf U, Wiemann S, Sahin Ö. miR-200bc/429 cluster targets PLCγ1 and differentially regulates proliferation and EGF-driven invasion than miR-200a/141 in breast cancer. Oncogene 2010; 29:4297-306. [DOI: 10.1038/onc.2010.201] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Uhlmann S, Buxton JA. A provincial and territorial review of hepatitis A in men who have sex with men. Can Commun Dis Rep 2007; 33:1-11. [PMID: 18163239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- S Uhlmann
- Epidemiology Services, BC Centre for Disease Control, Vancouver, British Columbia, Canada
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Iandiev I, Uckermann O, Pannicke T, Wurm A, Tenckhoff S, Pietsch U, Reichenbach A, Wiedemann P, Bringmann A, Uhlmann S. Reaktive Gliose bei einem Modell der Netzhautablösung beim Schwein. Klin Monbl Augenheilkd 2006. [DOI: 10.1055/s-2006-958766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Uhlmann S, Wiedemann P. Refractive lens exchange combined with pars plana vitrectomy to correct high myopia. Eye (Lond) 2006. [DOI: 10.1038/sj.eye.6702248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Uhlmann S, Kronseder A, Holz O, Welker L, Hessel H, Branscheid D, Magnussen H, Nowak D, Jörres RA. Wirkung von Zigarettenrauchextrakt und Wasserstoffperoxid auf das Wachstumsverhalten menschlicher Lungenfibroblasten. Pneumologie 2006. [DOI: 10.1055/s-2005-925499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Uhlmann S, Wiedemann P. Refraktiver Linsenaustausch in Kombination mit Pars-plana-Vitrektomie zur Korrektur der hohen Myopie. Klin Monbl Augenheilkd 2005. [DOI: 10.1055/s-2005-922177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
PURPOSE To describe the results of refractive lens exchange (RLE) combined with simultaneous pars plana vitrectomy (PPV) in the management of severe myopia. METHODS This retrospective study comprised 14 eyes of eight patients who had RLE to treat myopia of -19.0+/-5.4 diopters (D). Phacoemulsification, posterior chamber intraocular lens (IOL) implantation, and standard three-port vitrectomy were performed. Mean postoperative follow-up time was 30 months (range 12-49). RESULTS The postoperative best-corrected visual acuity (BCVA) was 0.68+/-0.23 compared to 0.37+/-0.24 preoperatively. There was no postoperative decrease in visual acuity in any eye. Mean postoperative spherical equivalent was -0.7 D (+/-1.6). At 30 months mean follow-up time, the spherical equivalents of nine eyes (64.3%) were within +/-1 D of emmetropia. There was no significant change in astigmatism due to operative procedures. During the 30 months follow-up period three eyes (21.4%) required neodymium : yttrium-aluminium-garnet (Nd : YAG) capsulotomy for posterior capsule opacification. No retinal detachments or cases of cystoid macular oedema (CME) were observed during the follow-up. CONCLUSION RLE was effective in correcting severe myopia. The simultaneously performed PPV may reduce the risk of postoperative retinal detachment. This was a pilot study, to draw definitive conclusions a prospective study has to be initiated.
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Affiliation(s)
- S Uhlmann
- Department of Ophthalmology, University of Leipzig, Leipzig, Germany.
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Thomasius R, Gouzoulis-Mayfrank E, Karus C, Wiedenmann H, Hermle L, Sack PM, Zeichner D, Küstner U, Schindler A, Krüger A, Uhlmann S, Petersen KU, Zapletalova P, Wartberg L, Schütz CG, Schulte-Markwort M, Obrocki J, Heinz A, Schmoldt A. [AWMF-guideline: cocaine-, amphetamine-, ecstasy- and hallucinogen-related disorders]. Fortschr Neurol Psychiatr 2005; 72:679-95. [PMID: 15580533 DOI: 10.1055/s-2004-818531] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Actually, guidelines for treatment of substance-related disorders were written under the overall control of the DG-Sucht e. V. and the DGPPN e. V. This appears within the framework of the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaft (AWMF). The leading objective of these guidelines is the description of the current scientifically proven and evidence-based medicine in addiction to derive recommendations to therapy. In this context, the guideline for treatment of cocaine-, amphetamine-, ecstasy-, and halluzinogen-related disorders is introduced.
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Affiliation(s)
- R Thomasius
- Klinik und Poliklinik für Psychiatrie und Psychotherapie, Universitätsklinikum Hamburg-Eppendorf.
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Uhlmann S, Meier P, Jochmann C, Kohen L, Wolf S, Wiedemann P. Offene Bulbusverletzungen. Klin Monbl Augenheilkd 2004. [DOI: 10.1055/s-2004-837019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Uhlmann S, Meier P, Pittasch K, Jochmann C, Kohen L, Wolf S, Wiedemann P. Bulbusrekonstruktion bei ausgedehnten Verletzungen des Hinterabschnittes. Klin Monbl Augenheilkd 2004; 221:706-12. [PMID: 15343456 DOI: 10.1055/s-2004-813212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Severe injuries of the posterior eye segment mostly occur during perforation or rupture of the globe. The first treatment includes primary surgical repair of the ocular wound and prophylactic scleral buckling in case of involvement of the posterior segment. Thereafter, a vitrectomy should be performed to remove vitreous hemorrhage and intraocular foreign bodies and to achieve a stable attachment of the retina. Therefore, temporary perfluorocarbon and permanent silicone oil tamponade are used. A predictor of poor visual outcome is the presence of retinal and choroidal injury. In our patients, the most important prognostic factor was the initial visual acuity after the injury. Vitrectomy can significantly reduce the incidence of enucleation. Currently, better visual outcome is achieved by advances in surgical techniques.
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Affiliation(s)
- S Uhlmann
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Leipzig AöR, Leipzig
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Francke M, Uhlmann S, Pannicke T, Goczalik I, Uckermann O, Weick M, Härtig W, Wiedemann P, Reichenbach A, Bringmann A. Experimental dispase-induced retinopathy causes up-regulation of P2Y receptor-mediated calcium responses in Müller glial cells. Ophthalmic Res 2003; 35:30-41. [PMID: 12566861 DOI: 10.1159/000068192] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2002] [Indexed: 11/19/2022]
Abstract
During proliferative vitreoretinopathy (PVR) Müller glial cells show an up-regulation of their responsiveness to extracellular adenosine 5'-triphosphate (ATP). In the present study, we investigated if such a glial cell response is also a feature for other retinopathies besides PVR. To this aim, the proteolytic enzyme, dispase (0.1 U), was injected into the vitreous of rabbit eyes. After 3 weeks, a distinct retinopathy had developed which showed no signs of PVR. The retinopathy was characterized by strong alterations of the retinal vasculature in the medullary rays, by photoreceptor degeneration, retinal atrophy, and activation of microglial cells. Müller cells became reactive, as indicated by up-regulation of glial fibrillary acidic protein immunoreactivity and by hypertrophy involving subretinal fibrosis. Müller cell reactivity was also evidenced electrophysiologically by a down-regulation of their inwardly rectifying potassium currents and by an up-regulation of their responsiveness to extracellular ATP. Significantly more Müller cells from dispase-treated eyes showed ATP-evoked calcium (83%) and current responses (69%) when compared with cells from control eyes (13 and 9%, respectively). The results indicate that increased responsiveness to extracellular ATP may be a more general feature of Müller cell gliosis, and is also observed in retinopathies besides PVR.
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Affiliation(s)
- M Francke
- Department of Neurophysiology, Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
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Uhlmann D, Uhlmann S, Löffler BM, Witzigmann H, Spiegel HU. Pharmacological regulation of postischemic sinusoidal diameters in rats--a new approach for reducing hepatic ischemia/reperfusion injury. Clin Hemorheol Microcirc 2002; 24:233-46. [PMID: 11564912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
UNLABELLED Ischemia leads to profound endothelin-related constriction of the hepatic microcirculation with resulting disturbances in blood and oxygen supply. The aim of the study was to modulate hepatic microvascular diameters by blocking endothelin receptors with bosentan, and also to find the best possible vessel width (as produced by bosentan) for minimizing ischemia/reperfusion injury. METHODS In an in vivo rat model hepatic ischemia was induced for 30 minutes by crossclamping the hepatoduodenal ligament. The endothelin receptor antagonist (ERA) bosentan was administered before ischemia in stepwise dosages of 0.1, 1.0 and 10 mg/kg bw i.v. and 10 mg/kg bw intraportally (i.p.). Vasoactive effect was assessed by in vivo microscopy. The influence on hepatic oxygen supply and hepatocellular function was evaluated by measuring local tissue pO(2) and AST levels. RESULTS Because of ischemia sinusoidal diameters were reduced to 76.3 +/- 7.4% compared with values found in sham-operated animals. After administration of 0.1 mg/kg ERA (bosentan) the sinusoids remained constricted (89.7 +/- 9.9%). Blocking endothelin receptors with 1 mg/kg bosentan avoided sinusoidal constriction (99.0 +/- 8.8%, p<0.05) and led to the most effective reduction of AST level peak after 6 h of reperfusion (244.0 +/- 34.2 U/l vs 422.9 +/- 163.3 U/l in untreated ischemia). 10 mg/kg i.v. caused an increase in sinusoidal diameter to 109.1 +/- 6.4% and 10 mg/kg intraportally to 136.8 +/- 19.3% and even an increase in AST levels (618.9 +/- 209.3 U/l). Hepatic ischemia led to a significant decrease of local tissue pO(2) after reperfusion (9.4 +/- 1.2 mm Hg; p<0.05 vs sham: 16.8 +/- 1.8 mm Hg). The greatest improvement in postischemic oxygen supply was found in the 1.0 mg/kg group (12.9 +/- 1.0 mm Hg; p< 0.05 vs ischemia). Venular diameter changed almost to the same extent as sinusoidal diameter. Perfusion rate was significantly increased and sticking of leukocytes in sinusoids and venules was reduced after doses of 1 and 10 mg/kg bw bosentan i.v. (p<0.05). IMPLICATIONS In this model we were able to regulate the diameters of sinusoids and postsinusoidal venules incrementally. We conclude that the avoidance of constriction, without excessive vasodilatation gives increased perfusion rates with improved hepatic oxygen supply and hepatocellular function.
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Affiliation(s)
- D Uhlmann
- Second Department of Surgery, University of Leipzig, Germany.
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Affiliation(s)
- S Uhlmann
- Klinik und Poliklinik für Augenheilkunde, Universität Leipzig.
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Uhlmann S, Friedrichs U, Eichler W, Hoffmann S, Wiedemann P. Direct measurement of VEGF-induced nitric oxide production by choroidal endothelial cells. Microvasc Res 2001; 62:179-89. [PMID: 11516247 DOI: 10.1006/mvre.2001.2334] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Vascular endothelial growth factor (VEGF) and nitric oxide (NO) seem to be involved in the process of angiogenesis, but their interactions are not clearly understood. The aim of this study was to investigate the influence of VEGF on NO production of choroidal endothelial cells (CEC) and its importance in angiogenesis. Experiments were performed using cultured bovine CEC. Basal NO release of unstimulated CEC was measured and compared to NO release of VEGF-stimulated CEC (1, 10, and 100 ng/ml). Further, cells were pretreated with N(omega)-nitro-L-arginine methyl ester (L-NAME, 1 and 2 mM) and incubated with and without VEGF (10 ng/ml) to investigate the effect of blocking NO synthase. NO release into the medium was assessed by an amperometric NO sensor. To show the importance of NO in angiogenesis, proliferation and migration of CEC were measured after VEGF stimulation and in the presence or absence of L-NAME (1 and 2 mM). Unstimulated CEC continuously produced low levels of NO. Stimulation of the cells with VEGF resulted in a dose-dependent increase in NO release. The time course after stimulation with 10 ng/ml VEGF was characterized by a prompt initial rise up to 140% of unstimulated levels and a subsequent sustained increase over 120 min. Pretreatment with L-NAME attenuated the VEGF-induced response. L-NAME incubation alone led to a reduction in basal NO release. L-NAME also significantly diminished the VEGF-enhanced CEC proliferation and migration. The results demonstrate that VEGF enhances the formation of NO in cultured CEC. The blockade of NO production reduces CEC proliferation and migration, an effect which may be important for controlling angiogenesis, especially in reducing neovascularization in age-related macular degeneration in the eye.
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Affiliation(s)
- S Uhlmann
- Department of Ophthalmology, University of Leipzig, Liebigstrasse 10-14, Leipzig, 04103, Germany
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Abstract
The aim of this study was to explore the complex role of endothelins (ETs) in hepatic ischemia-reperfusion injury and to minimize this type of injury by nonselective ET receptor blockade. In an in vivo rat model, hepatic ischemia was induced for 30 min. The rats were divided into three groups: (1) sham operated, (2) untreated ischemic, and (3) group treated with the nonselective ET receptor antagonist bosentan (1 mg/kg body weight iv). Blockage of the ET system during ischemia-reperfusion was assessed by: (1) in vivo microscopic analysis, (2) measurement of local tissue PO2, (3) laser Doppler flowmetry, (4) transaminases, and (5) tumor necrosis factor (TNF)- serum levels. During liver ischemia, anoxia (mean liver pO2 decreased from 14.7 to 1.5 mm Hg) and TNF- (levels rose from 0 pg/mL to 145.3 pg/mL at the end ofischemia) were associated with the release of ETs. Immunoreactive ET-1 (ir-ET-1) plasma levels (basal levels: 12.1+/-1.8 pg/mL) went up by 2.6-fold (32.1+/-6.8 pg/mL) after 15 min and by 11.7-fold (142.1+/-32.6 pg/mL) after 120 min of reperfusion. Increased plasma levels of ir-ET-1 were associated with sinusoidal constriction to 77.6+/-7.1% of basal diameters. This constriction led to significant decreases in perfusion rate (77+/-3%), local tissue PO2 (6.9+/-2.7 mm Hg), and erythrocyte flux (61.7+/-13.8% of basal values). Hepatocellular damage, evaluated via the serum level of aspartate aminotransferase (AST, increase to 393.5+/-68.3 U/L, preoperative 23.9+/-2.0 U/L) was detectable 6 h after reperfusion (p < .05). Administration of bosentan before 30 min of ischemia significantly reduced ischemia-reperfusion injury and was associated with an increase of ir-ET-1 levels to 110.8+/-12.0 pg/mL and 94.1+/-25.0 pg/mL after 15 and 120 min of reperfusion. Sinusoidal diameters were maintained at nearly 100% in the treatment group instead of 77%, while perfusion rate (88+/-2%) and tissue PO2 (12.1+/-1.0 mm Hg) rose significantly in contrast with the nontreatment group (p < .05). Hepatocellular damage was reduced (AST levels after 6 h of reperfusion 244.0+/-34.4 U/L, p <.05), and leukocyte sticking and rolling were diminished (p < .01). In the treatment group, bosentan values of 5.6+/-0.7 and 2.9+/-0.4 ng/mL after 15 and 120 min of reperfusion were measured. In conclusion the release of endothelins is combined with microcirculatory disturbances and local hypoxia, thereby causing liver damage. By protecting the liver microcirculation, ET receptor blockade of both receptors at a low dose increased blood and oxygen supply to the liver and reduced hepatocellular injury. These results constitute the bases for further studies and transfer into clinical practice.
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Affiliation(s)
- D Uhlmann
- Department of Surgery, University of Leipzig, Germany.
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Abstract
During ischemia-reperfusion an imbalance between endothelin (ET) and nitric oxide (NO) can be responsible for microcirculatory disturbances. The aim of this study was to restore the ET/NO balance to reduce the ischemia-reperfusion injury. Hepatic ischemia was induced for 30 min in 56 Wistar rats. Sham operation, ischemia and treatment groups with the ET receptor antagonist (ERA) bosentan (1 mg/kg body weight i.v.) and the NO donor L-arginine (400 mg/kg body weight i.v.) were performed. For evaluation of hepatic microcirculation in vivo microscopy was carried out 30-90 min after reperfusion. Local hepatic tissue PO2, laser Doppler flow and aspartate aminotransferase/alanine aminotransferase (AST/ALT) levels were measured. Increased ET caused sinusoidal constriction after reperfusion to 76% of the sham group (p < 0.05), leading to significant decrease in perfusion rate (82%), liver tissue PO2 (6.9 mmHg) and erythrocyte flux (45.2% of sham group). Hepatocellular damage could be detected 6 h after reperfusion by AST/ALT increase (p < 0.05). Sinusoidal diameters were maintained at baseline in the ERA (98%) and NO (102%) groups (p < 0.05). Increased percentage of leukocytes sticking in sinusoids (144%) and venules (435%) was reduced by therapy to 110/253% (ERA) and 111/324% (NO), respectively (p < 0.05). Perfusion rate was increased to 93 and 94% (p < 0.05 vs ischemia). Local hepatic tissue PO2 was improved 30 min after reperfusion in the ERA (11.0 mmHg) as well as in the NO group (11.5 mmHg; p < 0.05 vs ischemia). Measurement with a laser Doppler flow meter revealed significant improved erythrocyte flux in both therapy groups (p < 0.05 vs ischemia). Also, the post-ischemic AST/ALT increase was reduced by therapy. In conclusion, ET evokes strong constriction of post-ischemic sinusoids, leading to microcirculatory disturbances. The maintenance of the ET/NO balance by blocking ET receptors, or providing an NO donor, protects liver microcirculation and reduces hepatic ischemia-reperfusion injury.
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Affiliation(s)
- D Uhlmann
- Second Department of Surgery, University of Leipzig, Germany.
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Uhlmann D, Uhlmann S, Palmes D, Spiegel HU. Endothelin receptor blockade as a therapeutic strategy in ameliorating postischemic damage to the liver microcirculation. J Cardiovasc Pharmacol 2000; 36:S351-3. [PMID: 11078418 DOI: 10.1097/00005344-200036051-00102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ischemia leads to profound endothelin- (ET) related constriction of hepatic microvessels, causing disturbances in blood and oxygen supply. The aim of the study was to modulate hepatic microvascular diameters by blocking ET receptors to find the optimal therapeutic vessel width for reduction of ischemia-reperfusion injury. In an in vivo model (84 female Wistar rats, 250-300 g) with portal decompression by means of a splenocaval shunt, normothermic hepatic ischemia was induced for 30 min by crossclamping of the hepatoduodenal ligament. The ET receptor antagonist (ERA) bosentan was administered before induction of ischemia in different dosages [0.1, 1.0 and 10.0 mg/kg body weight (BW) i.v. and 10 mg/kg BW intraportally (i.p.)]. The effect on microcirculation was assessed by in vivo microscopy and influence on hepatocellular function by measurement of aspartate aminotransferase (AST) levels. Sinusoidal diameters were reduced as a result of ischemia to 76.3 +/- 7.4% compared with values received from sham-operated animals. After application of 0.1 mg/kg of bosentan, sinusoids remained constricted (89.7 +/- 9.9%, AST 255.0 +/- 12.8 U/l). Blocking ET receptors with 1 mg/kg bosentan avoided sinusoidal constriction (99.0 +/- 8.8%, p < 0.05) and led to the most effective reduction of AST level peak after 6 h of reperfusion (244.0 +/- 34.2 U/l vs 422.9 +/- 163.3 U/l in untreated ischemia). Bosentan (10 mg/kg i.v.) caused an increase in sinusoidal diameter to 109.1 +/- 6.4% (AST 311.7 +/- 33.6 U/l) and 10 mg/kg i.p. to 136.8 +/- 19.3% and even increase AST levels (618.90 +/- 209.32 U/l). After intravenous application of 1 and 10 mg/kg BW bosentan the perfusion rate was significantly increased and sticking of leukocytes in sinusoids and venules reduced (p < 0.05). In our model, diameters of sinusoids and postsinusoidal venules could be regulated gradually. We conclude that the avoidance of constriction, but not an excessive vasodilation leads to increased perfusion rate and hence improved hepatocellular function.
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Affiliation(s)
- D Uhlmann
- Second Department of Surgery, University of Leipzig, Germany.
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Abstract
One of the changes produced by ischemia and reperfusion is endothelin (ET)-mediated constriction of the hepatic vascular bed. This leads to microcirculatory disturbances and reduced blood flow, thereby causing local hypoxia and liver damage. Our aim was to induce stepwise changes of microvascular vessel diameters so as to define the best protective vessel width that could be produced by drug therapy and thereby to minimize ischemia/reperfusion injury. The mixed ET receptor antagonist bosentan was used in different dosages in a rat liver ischemia/reperfusion model with splenocaval shunt. In vivo microscopy was performed 30-90 min after reperfusion and local hepatic tissue pO2 was determined, together with aspartate aminotransferase/alanine aminotransferase (AST/ALT). After ischemia, sinusoidal diameters were significantly reduced to 76 +/- 7% of those in the control group. After the administration of bosentan in dosages of 0.1, 1, and 10 mg/kg body weight iv and 10 mg/kg body weight intraportally we found diameters of 83 +/- 4, 98 +/- 2, 109 +/- 6, and 137 +/- 19%, respectively. Perfusion rate and leukocyte-endothelium interactions showed dependence on sinusoidal diameters, with the best results in the group where preischemic sinusoidal vessel width had been maintained. Local tissue pO2 and transaminase levels also showed that oxygen supply was sufficient and that hepatocellular injury was most minimized in this group. Graduated blocking of ET receptors allows stepwise regulation of sinusoidal and postsinusoidal venular vessel width and offers a treatment strategy for pathophysiological situations that are associated with ET-induced vasoconstriction. The results suggest that maintenance of preischemic microvascular diameter is the best therapeutic approach.
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Affiliation(s)
- H U Spiegel
- Department of General Surgery-Surgical Research, Westfaelische Wilhelms-University of Muenster, Germany.
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Abstract
In vivo microscopy is an excellent technique for investigating the microcirculation and until recently the only one that allowed direct visualization. Rat liver has been widely studied, because microcirculatory disorders play a pivotal role in the pathogenesis of organ failure during hepatic ischemia, transplantation, hemorrhagic shock, endotoxemia, and sepsis. The state of the microcirculation is an important prognostic factor for the reestablishment of organ function after these injuries. This article introduces the most common procedures for in vivo microscopy of the rat liver, summarizes the available fluorescent dyes, and gives an overview of criteria for the expression and evaluation of microscopic findings. Particular emphasis is given to a description of the different parameters assessed by direct observation of hepatic microcirculation, such as perfusion rate, leukocyte-endothelium interactions, leukocyte velocities, and phagocytic activity. Examples of normal range values are given. This overview is intended to help those wanting to introduce this method into their research and who are embarking on intravital microscopy for the first time, and to enable them to decide which techniques are appropriate for answering special questions.
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Affiliation(s)
- S Uhlmann
- Department of Ophthalmology, University of Leipzig, Germany.
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Frauenheim T, Weich F, Köhler T, Uhlmann S, Porezag D, Seifert G. Density-functional-based construction of transferable nonorthogonal tight-binding potentials for Si and SiH. Phys Rev B Condens Matter 1995; 52:11492-11501. [PMID: 9980258 DOI: 10.1103/physrevb.52.11492] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Uhlmann S, Frauenheim T, Stephan U. Molecular-dynamics subplantation studies of carbon beneath the diamond (111) surface. Phys Rev B Condens Matter 1995; 51:4541-4546. [PMID: 9979300 DOI: 10.1103/physrevb.51.4541] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Grimm WD, Curth K, Koch M, Nossek H, Uhlmann S, Walther C. [Clinically controlled, integrated study on plaque inhibition with zinc-fluoride-hexetidin]. Stomatol DDR 1989; 39:16-20. [PMID: 2623709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study investigated the effect of Zinc-Fluorid-Hexetidin comparing with positive control group (Chlorhexidin) and negative control group (experimental gingivitis). The result demonstrated that a mouthrinse containing Zinc-Fluorid-Hexetidin prevented the development of plaque without complications.
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