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ABSTRACT: We investigated the feasibility of using flat panel volumetric computer tomography (fpVCT) for the detection of orthotopically implanted renal carcinomas in nude mice.
One million renal cell carcinoma cells [A-498 line (Braunschweig, Germany), in 0.2 ml phosphate-buffered solution (PBS), pH 7.4] were injected into the left kidney of each of the eight nude mice. Each mouse was imaged twice (12 and 16 weeks after implantation) with fpVCT (GE prototype with circular gantry with two 1024 x 1024, 200 microm pixel size, aSi/CsI flat panel detector) after injection of 200 microl contrast medium to check for tumour spread. After 16 weeks the mice were killed and dissected, and the imaging findings in liver, kidneys and lung were compared with the macroscopic findings.
No local evidence of tumour or of metastatic spread was seen on fpVCT after 12 weeks in any of the mice. After 16 weeks fpVCT revealed tumour growth in 6 of the 16 kidneys. Two mice had each developed a multifocal renal cell carcinoma and one mouse, a bilateral renal tumour manifestation. In one mouse liver metastases were seen. The fpVCT findings correlated well with the observations recorded in the pathological examination.
fpVCT is an innovative and noninvasive imaging procedure that can be used for longitudinal investigation of tumour progression following orthotopic implantation of renal cell carcinoma to small animals. The use of a system of this kind will make a decisive contribution to reducing the number of animals used in experimental test projects.
Der Urologe 01/2008; 46(12):1710-4. · 0.50 Impact Factor
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ABSTRACT: After cystectomy two principal types of urinary diversion are used for the surgical reconstruction of the urinary tract: incontinent and continent. In the continent type of urinary diversion, a differentiation must be made between those with and without catheterization for voiding. Besides urothelial cancer other reasons for urinary diversion include neurogenic bladder palsy (connatal or acquired) due to meningomyelocele or connatal diseases like bladder exstrophy. The main objective of the clinical urologist when selecting urinary diversion are to achieve continence and to preserve upper urinary tract function. Knowledge of the different forms of urinary diversion is critical for the exact interpretation of the images. This review presents the typical imaging techniques after a description of the basic surgical features of urinary diversion. CT urography and MR urography are becoming increasingly important as further imaging tools for controlling urinary diversions.
RöFo - Fortschritte auf dem Gebiet der R 11/2007; 179(10):1025-34. · 2.76 Impact Factor
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Der Urologe 10/2007; 46(9):1177-8. · 0.50 Impact Factor
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Der Urologe 08/2007; 46(9):1177-1178. · 0.50 Impact Factor
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ABSTRACT: Following surgical excision of a prevesical haematoma, topical negative pressure was used to promote wound closure. The development of a vesicocutaneous fistula at the incision site may have been an indirect complication of the therapy.
Journal of wound care 11/2005; 14(9):406.
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ABSTRACT: Gastrin releasing peptide (GRP) is a growth factor for renal cell carcinoma (RCC) and it has vasoactive properties. Blockade of GRP receptor inhibits the growth of GRP receptor positive and negative tumors in nude mice, suggesting GRP effects other than those related to tumor epithelium. Therefore, in this study we analyzed the effects of GRP receptor blockade on neoangiogenesis in RCC.
GRP receptor expression was determined in human RCC and corresponding normal tissue by real-time reverse transcriptase-polymerase chain reaction, immunohistochemistry and confocal laser scanning microscopy. Multicellular spheroids of the A498 RCC line were implanted into dorsal skin fold chambers of athymic nude mice. Neoangiogenesis was measured by intravital microscopy after blockade of GRP receptors by the GRP antagonist RC-3095. The influence of GRP on vascular endothelial growth factor secretion in A498 cells was studied in vitro.
GRP receptor expression was immunolocalized in tumor cells and microvessels. Implanted tumor cell spheroids and spheroid microvessels of the chamber also expressed GRP receptors. Spheroid neoangiogenesis was significantly inhibited by RC-3095 when given immediately after spheroid implantation. Vascular endothelial growth factor secretion of A498 cells was not affected by GRP.
RCC angiogenesis is sensitive to GRP receptor blockade. Therefore, GRP receptors may not only stimulate tumor cell proliferation, but also affect tumor microcirculation.
The Journal of Urology 07/2005; 173(6):2154-9. · 3.75 Impact Factor
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ABSTRACT: Alterations in microvascular perfusion of the intestine after hepatic ischemia/reperfusion have been suggested as an important cause of postoperative septic complications. We therefore investigated small bowel microcirculation and mucosal injury after liver ischemia/reperfusion in a rat model. Furthermore, we analyzed the effects of the regulatory peptides vasoactive intestinal polypeptide and gastrin-releasing peptide for their splanchnic vasoactivity.
Hepatic ischemia was induced by clamping of the left hepatic artery and vein for 40 min, followed by 60 min of reperfusion. The control group was treated similarly, but without clamping of the liver vessels. Ten minutes after clamping of the hepatic vessels, vasoactive intestinal polypeptide or gastrin-releasing peptide, respectively, were continuously infused intravenously in the experimental groups. Small bowel microcirculation and mucosal injury were assessed using intravital microscopy and the Chiu-score, respectively.
The functional capillary density of the small intestine following ischemia and reperfusion of the left hepatic lobe significantly decreased compared to normal controls in both the mucosa and the smooth intestinal muscle. Red blood cell velocity decreased, whereas leukocyte-endothelium adherence, stasis index and the mucosal injury score increased. Administration of vasoactive intestinal polypeptide resulted in an increase of functional capillary density in the mucosa and of the red blood cell velocity and a decrease in the stasis index. The mucosal injury score was significantly higher in reperfused animals without treatment. The application of gastrin-releasing peptide resulted in an isolated increase of the red blood cell velocity. Leukocyte adherences could not be altered by the regulatory peptides.
We conclude that hepatic ischemia/reperfusion injury leads to significant alterations of small bowel microcirculation and mucosal injury. Vasoactive intestinal polypeptide and gastrin-releasing peptide attenuate the damage in a different manner.
International Journal of Colorectal Disease 02/2005; 20(1):42-8. · 2.38 Impact Factor
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ABSTRACT: Cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) are frequently up-regulated in malignant tumours and play a role in proliferation, apoptosis, angiogenesis and tumour invasion. In the present study, the expression of COX-2 and VEGF in renal cell carcinoma (RCC) was analysed and correlated with the microvessel density (MVD).
COX-2 and VEGF were analysed by realtime reverse transcriptase-polymerase chain reaction and immunohistochemistry. The MVD was assessed by CD31 immunohistochemistry. The expression of COX-2 and VEGF was determined in the RCC cell lines A498 and Caki-1 under short-term hypoxia and in multicellular tumour cell aggregates. COX-2 was expressed in RCC by tumour epithelia, endothelia and macrophages in areas of cystic tumour regression and tumour necrosis. COX-2 protein in RCC was not altered in comparison with normal renal tissue. VEGF mRNA was up-regulated in RCC and positively correlated with MVD. RCC with high up-regulation of VEGF mRNA showed weak intracytoplasmic expression of VEGF in tumour cells. Intracytoplasmic VEGF protein expression was negatively correlated with MVD. In RCC with necrosis the MVD was reduced in comparison with RCC without necrosis. A498 RCC cells down-regulated COX-2 and up-regulated VEGF under conditions of hypoxia. In Caki-1 cells COX-2 expression remained stable, whereas VEGF was significantly up-regulated. In multicellular A498 cell aggregates COX-2 and VEGF were up-regulated centrally, whereas no gradient was found in Caki-1 cells.
COX-2 and VEGF are potential therapeutic targets because COX-2 and VEGF are expressed in RCC and associated cell populations such as endothelia and monocytes/macrophages.
Histopathology 01/2005; 45(6):603-11. · 3.08 Impact Factor
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ABSTRACT: Xenin (1-25) has been detected in various locations in mammalians. It has structural similarities with neurotensin and its intestinal effects are claimed to be mediated by neurotensin receptors. It has been shown to influence gastrointestinal motility. The effects of xenin (1-25) on intestinal microvascular perfusion after ischemia/reperfusion have not been investigated yet. Therefore, the superior mesenteric artery was clamped for 40 min in Wistar rats (n=8). Ten minutes prior to reperfusion, intravenous infusion of xenin (1-25) (5 nmol/kg/h) was started. By means of intravital microscopy, microvascular perfusion in the mucosal layer was assessed. Animals (n=8) with and without clamping of the superior mesenteric artery and infusion of the carrier solution served as controls. After ischemia/reperfusion, xenin (1-25) increased the density of perfused microvessels and the capillary red blood cell velocity compared to ischemic controls. Capillary red blood cell velocity was elevated (p<0.05). Xenin (1-25) improved the heterogeneous distribution of mucosal blood flow during reperfusion demonstrated by an increase of both the perfusion index and the percentage of perfused microvessels. We conclude that the effects of xenin (1-25) on intestinal microcirculation are significantly different from those previously described for neurotensin. A more complex effector mechanism must be postulated that may involve other regulatory peptides and receptors.
Regulatory Peptides 07/2002; 107(1-3):23-7. · 2.11 Impact Factor
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Transplantation Proceedings 06/2002; 34(3):1049. · 1.00 Impact Factor
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ABSTRACT: Single ectopic ureters are a rare malformation in children. Therapy consists of ureteral reimplantation. However, in case of bilateral single ectopic ureters, subsequent malformation of the bladder trigone and bladder neck may result in additional voiding dysfunction, and ureteral reimplantation alone may not solve the urologic problems.
The authors report their experience with 2 girls, in whom bilateral single ectopic ureters were treated by ureteral reimplantation in early childhood and who did not gain adequate bladder control during following years.
Videourodynamic evaluation was done in both girls. No bladder overactivity was found during the urodynamic studies. However, cystography showed a widely open bladder neck during filling with no sufficient bladder neck closure shown by urethral pressure profile studies. When blocking the bladder outlet by balloon catheters, adequate bladder filling volume was achieved. Incontinence was cured by implantation of an AMS 800 artificial sphincter system in a 10-year-old girl. A 7-year-old girl was regarded to be too young for sphincter implantation and is waiting for surgery within the next years.
Insufficient development of trigone and bladder neck with subsequent urinary incontinence has to be kept in mind when deciding on surgical procedures in children with bilateral single ectopic ureters.
Journal of Pediatric Surgery 06/2002; 37(5):E15. · 1.45 Impact Factor
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ABSTRACT: The surgically induced split hydronephrotic kidney has been generally accepted as a valid model for the assessment of renal microcirculation by means of intravital microscopy. Whereas nearly all previous work on this issue has been done with a transillumination technique, we used an epiillumination model that is suitable for investigation of microvascular perfusion in both normal and hydronephrotic kidneys without surgical manipulation of the ureter. By means of the congenital unilaterally hydronephrotic Tauchi rat, microcirculation of the hydronephrotic and that of the nonhydronephrotic kidney were compared. For that purpose both the hydronephrotic and the nonhydronephrotic kidneys of Tauchi rats were exteriorized on a specially designed microscopy stage. After injection of FITC-dextran and rhodamine 6G, microvascular perfusion was assessed in both kidneys. The new model allowed visualization of arterioles, capillaries, and postcapillary venules in both the hydronephrotic and the nonhydronephrotic kidneys. Glomeruli could only be regularly seen in the hydronephrotic kidney, but also in some normal kidneys. Capillary blood cell velocity was significantly higher in the hydronephrotic kidneys (0.67 +/- 0.03 mm/s) compared to the normal kidney (0.32 +/- 0.05 mm/s; P < 0.05), whereas capillary diameters were smaller (4.2 +/- 0.02 microm vs. 5.7 +/- 0.2 microm; P < 0.05). In addition, the hydronephrotic kidney showed a significantly lower density of perfused microvessels compared to the normal controls. Epiillumination intravital microscopy allows assessment of the cortical microcirculation in both the hydronephrotic and the nonhydronephrotic kidneys without surgical induction of hydronephrosis. The hydronephrotic kidney shows significant microcirculatory differences compared to normal kidneys that should be taken into account when using a hydronephrotic model for pharmacological testing.
Microvascular Research 10/2001; 62(2):172-8. · 2.83 Impact Factor
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ABSTRACT: Alterations caused by renal obstruction in developing kidneys are of particular interest in basic research of congenital obstructive uropathy. In rats nephrogenesis mainly occurs 7 to 10 days postnatally. Therefore, surgically induced neonatal ureteral obstruction in rats has been suggested to be analogous to congenital obstruction in the fetus. An attempt less prone to surgical artifacts and assessing even earlier developmental stages is to monitor the development of obstructed kidneys in rats with congenital obstructive uropathy.
Rats from an inbred strain with congenital renal obstruction in 70% of their littermates were observed. Morphologically, significant hydronephrosis was not detected before day 5 post partum and progressed with age. Unilateral obstructed kidneys were compared with contralateral kidneys and kidneys from healthy control animals at ages of 1, 5, 10, 18 and 32 days. A total of 72 renal units were investigated. The renal messenger RNA expression of renin and transforming growth factor-beta1 (TGF-beta1) was quantified by competitive quantitative reverse transcription polymerase chain reaction using a gene specific complementary RNA standard.
In controls the gene expression of renin decreased from day 1 to day 18 and remained stable. TGF-beta1 expression increased during the first 10 days and then decreased again. Renin expression of the obstructed kidneys was reduced (p <0.05) on day 1, increased to a maximum versus controls (p <0.01) on day 10 and decreased to an unchanged elevated level (p <0.01) on days 18 and 32. Renin expression of the contralateral kidneys showed no significant alterations to control kidneys. Messenger RNA expression of TGF-beta1 of obstructed kidneys stayed decreased during the first 10 days (p <0.05), then increased excessively on day 18 (p <0.01) and slightly decreased on day 32. TGF-beta1 expression of the contralateral kidneys was parallel to controls on a slightly elevated level, increased on day 18 and returned to control level on day 32.
Within the postpartum period of nephrogenesis gene expression of renin and TGF-beta1 was decreased in obstructed kidneys compared to controls. As the renin angiotensin system and TGF-beta1 have important functions in normal kidney development, these results suggest impaired nephrogenesis of congenital obstructed kidneys even before the onset of morphological signs of hydronephrosis. These features differ from surgical induced unilateral ureteral obstruction at birth and promise new insights into the pathophysiology of congenital obstructive uropathy.
The Journal of Urology 07/2001; 165(6 Pt 2):2289-92. · 3.75 Impact Factor
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ABSTRACT: Placement of an aortic wallstent for treatment of an abdominal aortic aneurysm (AAA) is a frequent therapeutic measure. Whereas AAA is known to mimic renal colic, aortic wallstent dislocation is a novel diagnostic problem. Herein, we report the first case of a patient with a dislocated aortic wallstent and subsequent aneurysm rupture and discuss appropriate diagnostic measures.
Scandinavian Journal of Urology and Nephrology 07/2001; 35(3):252-3. · 0.99 Impact Factor
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Transplantation Proceedings 10/2000; 32(6):1247-8. · 1.00 Impact Factor
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ABSTRACT: We investigated the effect of neurotensin and cholecystokinin (CCK) on intestinal microcirculation after ischemia-reperfusion.
Ischemia was induced in Wistar rats by occlusion of the superior mesenteric artery for 40 min. Ten minutes before reperfusion, infusion of either neurotensin or CCK was started. Afterwards, the microhemodynamics of the jejunum were examined by means of intravital microscopy.
Ischemia-reperfusion decreased functional capillary density from 873.4+/-18.1 to 362.5+/-8.3 cm(-1) and red blood cell velocity from 0.49+/-0.03 to 0.34+/-0.02 mm/s. Furthermore, leukocyte-endothelium interaction was increased. Neurotensin infusion significantly increased functional capillary density to 483.2+/-9.0 cm(-1) and red blood cell velocity to 0.69+/-0.01 mm/s in the mucosal capillaries compared with ischemic controls. Despite the amelioration of villus perfusion, the number of non-perfused villi significantly increased (11.8+/-3.6%) compared with ischemic controls. CCK infusion also resulted in a significant increase of functional capillary density (535.2+/-7.4 cm(-1)) and red blood cell velocity (0.67+/-0.01 mm/s). In contrast to neurotensin, the number of non-perfused villi was not increased (5.8+/-2.2%).
We conclude that neurotensin further aggravates perfusion inhomogeneity and stasis when administered during the ischemic period. In contrast, CCK has no negative influence on perfusion homogeneity after ischemia-reperfusion. It may be superior to neurotensin in the reconstitution of normal microvascular perfusion patterns after ischemia-reperfusion.
Langenbeck s Archives of Surgery 09/2000; 385(5):357-62. · 1.81 Impact Factor
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ABSTRACT: Octreotide (OCT) is used for the protection of pancreato-intestinal anastomoses and for treatment of acute pancreatitis. Its effect on jejunal microcirculation after ischemia-reperfusion has not been investigated.
Intestinal ischemia was induced in Wistar rats (n = 8) by occlusion of the superior mesenteric artery for 40 min. Prior to reperfusion infusion of OCT (7.5 microgram/h) was started (n = 8). Microvascular perfusion of the jejunal mucosal and muscle layers was assessed and compared with that of groups without intervention (n = 16) by means of intravital microscopy.
Ischemia-reperfusion decreased mucosal functional capillary density from 838.4 +/- 12.6 to 418.9 +/- 9.6 cm(-1). Mucosal capillary red blood cell velocity was reduced from 0.53 +/- 0.01 to 0.35 +/- 0.01 mm/s (P < 0.05). Permanent leukocyte adherence was increased. OCT without ischemia-reperfusion decreased functional capillary density (735.4 +/- 13.5 cm(-1)) and red blood cell velocity (0.46 +/- 0.01 mm/s). After reperfusion OCT led to perfusion heterogeneity demonstrated by villous stasis (26 +/- 4%) and a decrease in the index of mucosal perfusion (0.38 +/- 0.02). Functional capillary density was further decreased compared with ischemic controls (234.0 +/- 11.8 cm(-1)). Capillary red blood cell velocity was lower (0.30 +/- 0.01 mm/s) than in ischemic controls.
OCT impairs microvascular perfusion of the jejunum both under physiological conditions and after ischemia-reperfusion.
Journal of Surgical Research 08/2000; 92(2):186-92. · 2.25 Impact Factor
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ABSTRACT: Background: We investigated the effect of neurotensin and cholecystokinin (CCK) on intestinal microcirculation after ischemia-reperfusion. Method: Ischemia was induced in Wistar rats by occlusion of the superior mesenteric artery for 40 min. Ten minutes before reperfusion, infusion of either neurotensin or CCK was started. Afterwards, the microhemodynamics of the jejunum were examined by means of intravital microscopy. Results: Ischemia-reperfusion decreased functional capillary density from 873.4ᆦ.1 to 362.5NJ.3 cm-1 and red blood cell velocity from 0.49ǂ.03 to 0.34ǂ.02 mm/s. Furthermore, leukocyte-endothelium interaction was increased. Neurotensin infusion significantly increased functional capillary density to 483.2Nj.0 cm-1 and red blood cell velocity to 0.69ǂ.01 mm/s in the mucosal capillaries compared with ischemic controls. Despite the amelioration of villus perfusion, the number of non-perfused villi significantly increased (11.8Dž.6%) compared with ischemic controls. CCK infusion also resulted in a significant increase of functional capillary density (535.2lj.4 cm-1) and red blood cell velocity (0.67ǂ.01 mm/s). In contrast to neurotensin, the number of non-perfused villi was not increased (5.8DŽ.2%). Conclusion: We conclude that neurotensin further aggravates perfusion inhomogeneity and stasis when administered during the ischemic period. In contrast, CCK has no negative influence on perfusion homogeneity after ischemia-reperfusion. It may be superior to neurotensin in the reconstitution of normal microvascular perfusion patterns after ischemia-reperfusion.
Langenbeck s Archives of Surgery 07/2000; 385(5):357-362. · 1.81 Impact Factor
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ABSTRACT: We report herein the case of a 48-year-old man with long-term persistent primary hyperparathyroidism (pHPT) despite undergoing a parathyroidectomy in 1976, followed by a reoperation in 1978, for whom resection of a parathyroid adenoma in the upper mediastinum was eventually performed. His postoperative course was complicated by recurrent hypocalcemia refractory to oral calcium substitution and significantly elevated levels of parathyroid hormone (PTH). The radiological findings are presented, and we discuss the possible reasons for the coincidence of severe hypocalcemia with increased PTH levels in association with pHPT.
Surgery Today 02/2000; 30(11):1008-11. · 1.22 Impact Factor
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ABSTRACT: We investigated the effect of gastrin-releasing peptide (GRP) and its antagonist RC-3095 on intestinal microcirculation after ischemia-reperfusion. Intestinal ischemia was induced in female Wistar rats by occlusion of the superior mesenteric artery for 40 min. Ten minutes prior to reperfusion, infusion of GRP or RC-3095 was started. A jejunal segment was exteriorized and the microhemodynamics of the mucosa and submucosa were examined by intravital microscopy and compared both with normal and ischemic controls (without application of the regulatory peptide). Ischemia-reperfusion significantly decreased functional capillary density from 891.2 +/- 14.1 to 398.3 +/- 11.4 cm(-1). Capillary red blood cell velocity was reduced from 0.46 +/- 0.01 to 0.37 +/- 0.01 mm/s (p < 0.05). Furthermore, both sticking and rolling of leukocytes were enhanced. 3.4 +/- 1.1% of the villi were not perfused at all. GRP infusion reversed the microcirculatory ischemia-reperfusion injury by increasing functional capillary density to 669.8 +/- 8.3 cm(-1) and red blood cell velocity to 0.62 +/- 0.01 mm/s (p < 0.05). In addition, application of GRP resulted in a complete absence of stasis (0%) in the villi. Leukocyte-endothelium adherence remained unchanged when compared to the ischemic controls. In contrast, application of RC-3095 caused an aggravation of microcirculatory disturbances demonstrated by a markedly increased number of non-perfused villi (42.5 +/- 4.2%; p < 0.05 vs. ischemic controls) and a significantly reduced functional capillary density (346.2 +/- 8.4 cm(-1), p < 0.05 vs. ischemic controls). In addition, RC-3095 led to an increased permanent leukocyte adherence in postcapillary venules whereas rolling was significantly reduced when compared to normal controls. We conclude that GRP in pharmacological doses has a protective effect on intestinal microcirculation during reperfusion. Furthermore, these data suggest that endogenous GRP may play a decisive role in the maintenance of microvascular integrity during reperfusion.
Digestion 01/2000; 61(3):172-80. · 2.05 Impact Factor
