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.

PURPOSE: Renal 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. METHODS: Gastrin-releasing peptide and GRP-R expression in 17 ccRCC and 9 non-ccRCC were analyzed by RT-PCR, immunohistochemistry and double immunofluorescence staining. RESULTS: Tumor-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. CONCLUSIONS: Tumor-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.

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.

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.

Functional analysis of NKX3.1 in LNCaP prostate cancer cells by RNA interference.

The function of the androgen-regulated homeobox protein NKX3.1 in prostate cancer is controversial. NKX3.1 is necessary for correct prostate development and undergoes frequent allelic loss in prostate cancer. However, no mutations occur in the coding region and some particularly aggressive cancers over-express the protein. Nevertheless NKX3.1 is often referred to as candidate tumor suppressor gene. Recent findings suggest a function in protection against oxidative damage involved in prostate carcinogenesis. Thus NKX3.1 may act differently at various stages of prostate cancer. Unlike a classical tumor suppressor NKX3.1 is up-regulated by androgens and down-regulated by phytoestrogens. In this study we performed RNAi based functional analysis by knocking down NKX3.1 expression in LNCaP prostate cancer cells and analyzing the impact of NKX3.1 on gene expression and cell proliferation. Knock-down of NKX3.1 evoked a massive down-regulation of NKX3.1 expression, followed by reduction in mRNA expression of the androdrogen receptor (AR) and the insulin-like growth factor receptor (IGF-1R). Western blot analysis showed strong decreases of NKX3.1, AR, and IGF-1R protein expression. Concomitantly, cell proliferation decreased and expression of prostate-specific antigen (PSA) mRNA and its secretion were diminished, whereas expression of IGF binding protein 3 (IGFBP-3) and MMP tissue inhibitor 3 (TIMP-3) was up-regulated. In tumor cells not deprived of NKX3.1 expression this gene still has a function which might differ from its role in prostate development and carcinogenesis. NKX3.1 knock-down altered the expression of genes highly relevant in prostate cancer cell proliferation and apoptosis. In LNCaP NKX3.1 most probably plays the role of an androgen-regulated transcription factor whose down-regulation is paralleled by anti-proliferative and pro-apoptotic effects. Since NKX3.1 can regulate AR expression it may become a target for interference in hormone refractory prostate carcinoma.

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.

Anti-inflammatory effects of alphav integrin antagonism in acute kidney allograft rejection.

Integrin-mediated cell adhesion and signaling is essential to vascular development and inflammatory processes. Elevated expression of integrin alpha(v)beta(3) has been detected in ischemia-reperfusion injury and rejecting heart allografts. We thus hypothesized that the inhibition of alpha(v)-associated integrins may have potent anti-inflammatory effects in acute kidney allograft rejection. We studied the effects of a peptidomimetic antagonist of alpha(v) integrins in two rat models of renal allotransplantation, differing in degree of major histocompatibility complex mismatch. Integrin alpha(v)beta(3) was up-regulated in rejecting renal allografts. Integrin antagonist reduced the histological signs of acute rejection, the intensity of the mononuclear cell infiltration, and cell proliferation in the grafted kidneys. This could be correlated to a reduced leukocyte-endothelial interaction and an improved peritubular microcirculation observed by intravital microscopy. In vitro under laminar flow conditions, the arrest of monocytes to interleukin-1beta-activated endothelium was decreased. Furthermore, in co-culture models the proliferation and transmigration of monocytes/macrophages, endothelium, and fibroblasts induced by renal tubular epithelia was efficiently inhibited by alpha(v) integrin antagonism. These data reveal an important role of this integrin subclass in leukocyte recruitment and development and maintenance of acute rejection; blockade of alpha(v) integrins may provide a new therapeutic strategy to attenuate acute allograft rejection.

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.

Flat-panel-detector-based volumetric CT: performance evaluation of imaging for skeletal structures of small animals in comparison to multislice CT.

OBJECTIVES: The aim of this study was to compare the image performance of silicon-based flat-panel-detector-based volumetric computed tomography (fpVCT) to multislice spiral computed tomography (MSCT) for the visualization and detail detectability of skeletal structures in rodents of different development stages. MATERIALS AND METHODS: Rodents of different development stages were imaged with fpVCT (GE prototype with circular gantry with two 1024 x 1024, 200-microm pixel size, amorphous silicon/Cesium lodid (Csl) flat-panel detector) and eight-slice MSCT (LightSpeed Ultra). Imaging parameters (80 kVp, 100 mA) and the position of the rodents were identical in both techniques. Image quality, detail detectability, and contour of skeletal structures were judged by two observers in consensus using a 4-point scale (1 = unsatisfactory...4 = good). Findings were displayed and evaluated in axial slices, multiplanar reconstructions (MPR), maximum intensity projections (MIP) and volume rendering technique (VRT) in both modalities. Mean and standard of error of mean were calculated. RESULTS: In axial slices, visualization and detail detectability of very subtle skeletal structures, e.g., the basis of the skull was better in fpVCT than in MSCT (4 vs. 2 points). The MPRs of fpVCT showed less artifacts and more details than those of the MSCT. The MIPs and VRTs of the fpVCT demonstrated best image quality in all rodents of different development stages, whereas MSCT showed significant artifacts. CONCLUSION: fpVCT outperformed MSCT in imaging of small rodents. Due to the truly isotropic volume data set with high spatial resolution, fpVCT is a powerful tool in evaluating detailed skeletal structures.

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.

Changes of microvascular perfusion during acute ureteral obstruction in the rat kidney - the influence of gastrin releasing peptide.

INTRODUCTION: Peritubular renal microcirculation has not been directly visualized in acute ureteral obstruction. Therefore, we used epiilluminescence intravital microscopy and an animal model for the assessment of microvascular perfusion. MATERIALS AND METHODS: In group 1 (n = 5) the left kidney of Wistar rats was exteriorized and placed on a heatable stage for microcirculatory analysis. FITC-dextran was injected for plasma staining. Microcirculatory stability of the model was assessed by a repeated intravital microscopy at baseline, 60, and 120 minutes. In detail, the functional peritubular vessel density (FVD, total vessel length per area in cm/cm(2)), the red blood cell velocities and diameters in/of arterioles and peritubular capillaries and the perfusion index were measured. In group 2 (n = 7) the left ureter was obstructed after baseline microscopy. In a third group (n = 6) the influence of the antidiuretic and vasoconstrictive peptide gastrin releasing peptide on peritubular microcirculation of the obstructed kidney was measured. RESULTS: Repeated intravital microscopy did not induce major microcirculatory disturbances in group 1. Acute ureteral obstruction significantly decreased the index of peritubular perfusion. Moreover, FVD was found decreased at 120 minutes after a small rise at 60 minutes. Whereas blood cell velocities were not changed, arteriolar diameters were decreased after 120 minutes. GRP infusion lowered intrapelvic pressures at 60 and at 120 minutes. The transient increase of FVD (group 2) was not observed. The calculated peritubular flow remained nearly constant compared to a decrease in group 2. Histological assessment did not reveal any microscopy induced renal damage nor any differences between the groups. CONCLUSIONS: (1) The model is stable for a time period of at least 120 minutes and allows for the direct visualization of the renal peritubular vessels. (2) Peritubular microcirculation shows a significant deterioration during ureteral obstruction. (3) Infusion of GRP may be beneficial for the microcirculation of the acutely obstructed kidney.

The balance between MMP-2/-9 and TIMP-1/-2 is shifted towards MMP in renal cell carcinomas and can be further disturbed by hydrogen peroxide.

In malignant tumors the balance of matrix metalloproteinases (MMP) and tissue inhibitors of matrix metalloproteinases (TIMP) is disturbed. Radical oxygen species (ROS) and hydrogen peroxide potentially influence this balance. Therefore, we analyzed the balance of MMP and TIMP in renal cell carcinoma (RCC) specimens and cell lines. In RCC specimens MMP-2, MMP-9, TIMP-1, and TIMP-2 were immunohistochemically detected. Tumor-associated macrophages (TAM) as a potential source of ROS were characterized with an anti-CD68 antibody. Three RCC cell lines were treated with sublethal concentrations of hydrogen peroxide to simulate the effects of radical oxygen species. MMP-2 and MMP-9 protein expression was measured by zymography. mRNA expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 was assessed by quantitative reverse transcriptase polymerase chain reaction. Tumor cell-derived reactive oxygen species were measured by FACS analysis and dihydrorhodamine 123 oxidation. In RCCs the MMP and TIMP expression profile was variable. The balance between MMP and TIMP was shifted towards MMP in comparison to matched normal controls. TAM were localized in a close vicinity to MMP expresssing tumor cells. As in RCC specimens, the expression of MMP and TIMP in the analyzed RCC cell lines varied. Hydrogen peroxide induced MMP-2 and -9 mRNA and protein expression, whereas TIMP-1 and TIMP-2 mRNA levels remained unaffected in cell lines. Thus, the ratio between MMP and TIMP was shifted towards MMP. Tumor cells did not increase the production of reactive oxygen species stimulation with phorbol ester or hydrogen peroxide. In RCC the balance between MMP and TIMP is disturbed. Oxidative stress potentially increases this imbalance. TAM might be one source of hydrogen peroxide thus supporting the invasive properties of RCCs.

Dynamic assessment of angiogenesis in renal cell carcinoma spheroids by intravital microscopy.

PURPOSE: Renal cell cancer represents a suitable tumor model for in vivo observation of neo-angiogenesis. We used intravital microscopy and the well established dorsal skin fold chamber model to characterize neo-angiogenesis in freely implanted renal cell cancer spheroids. MATERIAL AND METHODS: Tumor spheroids were implanted into dorsal skin fold chambers of 8 nude mice. At days 3, 6, 10 and 14 after implantation the newly vascularized spheroid area, density of perfused microvessels in the spheroid versus the periphery, capillary center erythrocyte velocity and capillary diameter were recorded by intravital microscopy. Video images were analyzed by a computer assisted image analysis device. After the experiments the chambers were analyzed morphologically. RESULTS: The model enabled quantitative analysis of microcirculation and angiogenesis in the renal cell cancer spheroids during 14 days of observation. Mean spheroid center perfused microvessel density +/- SEM increased from 3 +/- 2 to 269 +/- 21 cm.-1 on days 3 to 10 and subsequently decreased to 189 +/- 38 cm.-1 on day 14. Spheroid periphery perfused microvessel density was significantly higher throughout the experiments, attaining a mean maximum of 522 +/- 34 cm. on day 14. Mean capillary diameter decreased continuously from 14.2 +/- 0.9 to 8.4 +/- 0.4 microm. on days 3 to 14. In contrast, mean capillary center erythrocyte velocity significantly increased during 14 days of observation from 0.09 + 0.02 mm. per second on day 3 to 0.24 +/- 0.08 mm. per second on day 14. Histological analysis after 14 days revealed the spheroids as cell clusters in the upper layers of the dorsal skin fold chamber. CONCLUSIONS: The model is suitable for the analysis of renal cell cancer angiogenesis. Although it is heterotopic, angiogenesis in renal cell cancer spheroids mimics important characteristics of human renal cell cancer.

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.