Markus Heuser

Treatment of Iatrogenic Postoperative Ureteral Strictures with Acucise Endoureterotomy

OBJECTIVES To determine factors influencing the outcome of Acucise endoureterotomy in patients with iatrogenic postoperative ureteral strictures after different open surgical procedures. MATERIAL AND METHODS Acucise endoureterotomy was performed in 18 patients with ureteral strictures after pyeloplasty (n = 5), renal transplantation (n = 5), ureteroenteric anastomosis (n = 3), calicoureterostomy (n = 1), ureterocystoneostomy (n = 1), hysterectomy (n = 1), ureterorenoscopy (n = 1) and transurethral resection of the ureteral orifice (n = 1). Success was determined as relief of clinical symptoms, improvement of renal function or improvement of radiographic findings. RESULTS The overall success rate was 61% (mean follow-up: 21.5 months). Six out of 18 patients showed relevant side effects. Neither the localization of the stricture nor the duration of postoperative ureteral stenting but the length of the stricture had influence on the postoperative outcome. Decreased renal function to less than 25% of the total function was always associated with failure of the treatment. The time period between the ureteral injury and the appearance of the ureteral stricture had influence on the outcome of the treatment. CONCLUSIONS Acucise endoureterotomy is effective in the treatment of postoperative ureteral strictures, but only in selected cases. The selection criteria are the time period from the primary operation to the appearance of the stricture (>6 months), the length of the stricture (<1.5 cm) and the renal function (>25% of the total function). In other cases, open surgical treatment of the ureteral stricture may provide better results.

Comparative analysis of COX-2, vascular endothelial growth factor and microvessel density in human renal cell carcinomas

Aims:  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).

Flat panel detector-based volumetric computed tomography (fpVCT): performance evaluation of volumetric methods by using different phantoms in comparison to 64-multislice computed tomography.

Objectives:Evaluation of a silicon-based flat panel volumetric computed tomography (fpVCT) and multislice CT in terms of volumetry of phantoms with different algorithms. Furthermore, to compare the different volumetric analysis methods themselves. Materials and Methods:Four phantoms of different materials have been scanned with fpVCT (GE prototype with circular gantry with 2 aSi/CsI flat panel detector) and a 64-slice spiral CT (MSCT: LightSpeed VCT). Three spherical phantoms of different materials and 1 phantom with an irregular shape were evaluated. True volumes were calculated in dependence from the diameter or by water displacement method. Imaging parameters (80 kVp, 100 mA) and the position of the phantoms were identical in both techniques. After reconstruction of the images different algorithms have been used 4 times for each phantom. These analysis methods have been performed: Region growing, threshold method, planimetry, 3-dimensional volumetry measurement by using the equation of an ellipsoid (ellipse) and an advanced lung analysis modus [single advanced lung analysis (ALA)]. The mean values and the standard deviations have been evaluated and compared with the true volumes. Results:In all phantoms fpVCT showed better results with lower deviations from the true values than in MSCT, especially for small volumes of the phantoms. However, the results of the ALA single method demonstrated no significant difference between the fpVCT and MSCT. The comparison of the different analysis methods revealed that 3-dimensional measurement with the ellipse method was the worst method for volume estimation, especially for the irregularly formed phantom. Conclusion:fpVCT was superior to MSCT in the volumetry of small objects. The ellipse method has been shown to be the worst for volumetry with the highest relative deviations from the true volume value. The single ALA method shows the lowest standard deviation thereby revealing a reproducible volumetric method for small nodules. However, further future developments of volumetric analysis methods are necessary to use them accurately in daily routine. Due to the truly isotropic volume data set with high spatial resolution fpVCT is a powerful tool for the volumetry of small nodules.

64-Multidetector-row spiral CT in pulmonary embolism with emphasis on incidental findings

AIM In this retrospective study, we assess the current role and future potential of computed tomography (CT) in the diagnostic algorithm of acute pulmonary embolism (PE). MATERIALS AND METHODS Two hundred patients underwent 64-multidetector-row spiral CT of the chest, pelvis, and thigh for suspected PE. CT scans were reviewed, and the degree of contrast enhancement and the presence of PE and/or (deep) venous thrombosis were recorded. In the case of PE, the level of thrombus was noted as central, main, or lobar. If the scan yielded a positive result for thrombosis, intravenous localization was also determined. Patient age, length of admission, clinical course, clinical indication, and incidental findings were registered as well. RESULTS PE was detected in 60 of the 200 patients with a high clinical probability of having PE (30%). Thirty-four patients had a positive CT scan result for venous thrombosis (17%). Twenty-four of the 60 patients had proximal deep venous thrombosis (40%), and 2 patients had arm venous thrombosis (3%). Thirty-four of the 60 patients had PE without venous thrombosis (57%). Eight of the 200 patients had deep venous thrombosis without suspicion of PE (4%). The distribution of the proximal thrombi showed 15 in a central artery (25%), 13 in a main pulmonary artery (22%), and 32 in a lobar segmental artery (53%). There was diffuse allocation of the thrombus in all lobes. Furthermore, CT scan noted a total of 120 incidental findings. CONCLUSION Our study indicates the potential clinical use of a diagnostic strategy for ruling out PE based on D-dimer testing and multidetector-row CT. A larger outcome study is needed before this approach can be adopted.

IMPAIRED NEPHROGENESIS IN RATS WITH CONGENITAL OBSTRUCTIVE UROPATHY

PURPOSE 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. MATERIALS AND METHODS 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. RESULTS 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. CONCLUSIONS 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.

Detection of gastrointestinal bleeding by using multislice computed tomography—acute and chronic hemorrhages

Nowadays, computed tomography (CT) is established for diagnosing gastrointestinal bleeding. In this retrospective study, the use of CT in diagnosing gastrointestinal bleeding was evaluated. Fifty-three patients received a contrast-medium-enhanced helical multislice CT (MSCT) to locate the bleeding site. Seventy-nine percent of the hemorrhage were acute gastrointestinal bleedings. Fifty-five percent of the acute hemorrhages were located via helical MSCT, 45% of the chronic bleeding sites were detected. Notably, bleeding of diverticula, tumors, and angiodysplasias were well demonstrated. In conclusion, contrast-medium-enhanced MSCT may be used effectively as a noninvasive diagnostic tool for detecting gastrointestinal bleedings.

Tumor-associated macrophages in clear cell renal cell carcinoma express both gastrin-releasing peptide and its receptor: a possible modulatory role of immune effectors cells

PurposeRenal cell carcinomas (RCC) frequently express the gastrin-releasing peptide receptor (GRP-R). Gastrin-releasing peptide (GRP) stimulates tumor cell proliferation and neoangiogenesis. Tumor-associated macrophages (TAM) comprise an important cellular component of these tumors. We analyzed the GRP/GRP-R network in clear cell RCC (ccRCC) and non-clear cell RCC (non-ccRCC) with special regard to its expression by macrophages, tumor cells and microvessels.MethodsGastrin-releasing peptide and GRP-R expression in 17 ccRCC and 9 non-ccRCC were analyzed by RT-PCR, immunohistochemistry and double immunofluorescence staining.ResultsTumor-associated macrophages expressed GRP and GRP receptor in ccRCC. Tumor cells and microvessels showed low to intermediate GRP-R expression in nearly all cases. In 12 ccRCC tumor epithelia also expressed low levels of GRP. Microvascular GRP expression was found in nine cases of ccRCC. For non-RCC, the expression of GRP and GRP receptor expression pattern was similar.ConclusionsTumor-associated macrophages are the main source of GRP in RCC. GRP receptor on TAM, tumor epithelia and microvessels might be a molecular base of a GRP/GRP receptor network, potentially acting as a paracrine/autocrine modulator of TAM recruitment, tumor growth and neoangiogenesis.

Current role and future potential of computed tomographic colonography for colorectal polyp detection and colon cancer screening¯incidental findings

AIM In this retrospective study, we assess the current role and future potential of computed tomographic (CT) colonography as a viable alternative imaging tool for colorectal polyp detection and colon cancer screening. MATERIALS AND METHODS Twenty patients have undergone virtual colonographic examinations with 64-multidetector-row spiral CT (MDCT), and three-dimensional images were created on a separate workstation that had the appropriate software for image processing. Images were reviewed by a radiologist, and anatomic division of the entire colon was used to locate the suspected lesions. Characteristics of bowel preparation, intracolonic, extracolonic, and incidental findings were noted, too. RESULTS Ten of the 20 patients (50%) had a positive CT colonography for polypoid lesions. Those lesions were distributed into the cecum (4 cases), colon ascendens (2 cases), colon descendens (2 cases), and sigma (2 cases). In 80%, bowel preparation was good, in 15% moderate, and in 5% inadequate. Furthermore, CT scan noted in total 20 incidental findings. CONCLUSION CT colonography is currently a viable alternative imaging tool for colorectal polyp detection. There are several clinical situations where CT colonography may play an important role in patient care. These include for example evaluation of the colon after an incomplete conventional colonoscopic examination or evaluation in patients who are clinically unfit to undergo conventional colonoscopy. At centers where there is expertise in data acquisition and interpretation, CT colonography is being offered as a routine imaging examination. With continued improvements in bowel preparation, colonic distention, and CT colonography interpretation by sufficient numbers of radiologists this technology might have a substantial influence on colon cancer screening.

Imaging of genitourinary trauma

The kidney, bladder and male urethra are the organs typically injured by blunt and penetrating trauma to the urinary tract, whereas the ureter is only rarely injured. The staging of genitourinary tract trauma has recently gained tremendous significance due to improvements in ultrasound, CT and MRI, including contrast-enhanced magnetic resonance angiography, and has become a helpful tool for decision making with regard to conservative and surgical management. Furthermore, interventional radiology may be helpful to control hemorrhage from vessels in the pelvic region that may not be easily accessed by open surgery. Therefore, this pictorial essay gives examples of the radiological presentation of genitourinary trauma and describes technical details of the diagnostic imaging modalities used.

Met-RANTES verbessert die mikrokapilläre Perfusion während der akuten Abstoßung am Dünndarmtransplantat der Ratte

Purpose of the Study: Acute rejection-induced microvascular injury results in graft dysfunction, ultimately leading to graft loss. Infiltration of T-cells and monocytes as a consequence of an enhanced leukocyte-endothelial cell interaction appears to play an important role in this deleterious process. Recruitment of these pro-inflammatory mononuclear cells to the vessel wall is mediated by chemokines such as RANTES, a potent chemoattractant for T cells, monocytes and natural killer cells. We investigated the effect of the RANTES antagonist Met-RANTES on rejection-induced microvascular perfusion failure in a rat model of small bowel transplantation. Methods: Heterotopic small bowel transplantation (SBTx) was performed in the fully allogeneic BN (RT1n) to LEW (RT11) and syngeneic LEW to LEW rat strain combination. Intravital microscopy was performed from postoperative day (POD) 1 to 7 both in the allogeneic and syngeneic groups. In the Met-RANTES group (n = 5) the excised small bowels were flushed with 100 μg Met-RANTES in 3 ml Ringers solution. Recipients were then treated with 200 μg Met-RANTES per day intravenously for 5 days. Intravital microscopy analysis of an exteriorized jejunal segment of the donor small bowel was performed on POD 5. The percentages of perfused villi and villus stasis, mucosal and muscular functional capillary densities (FCD), capillary diameters and red blood cell velocities, and finally permanent leukocyte adherence to postcapillary submucosal venules were assessed. Results: Syngeneic SBTx revealed homogenous perfusion of villi and muscle layers over the whole study period. Allogeneic SBTx showed a decline in perfusion from POD 1 until complete failure on POD 7 accompanied by a continuous increase in leukocytes-endothelial cell interaction (990 as compared to 556 sticker/mm2 in the allogeneic and syngeneic control group on POD 7, n= 6). On POD 5, mucosal FCD was significantly reduced in the allogeneic group (456 vs. 786 cm−1, n = 6) with near maximum leukocyte-endothelial cell interaction. In our preliminary study Met-RANTES treatment prevented this decrease in mucosal FCD (705 cm−1 on POD 5, n = 5), and reduced the number of leukocytes sticking to the postcapillary submucosal venules by approximately 50%. Conclusions: Blocking chemokines or their receptors, thereby limiting leukocyte-endothelial cell interaction, may constitute a useful therapeutic approach to the prevention of microvascular perfusion failure in acute transplant rejection.