Hybrid imaging with [68Ga]PSMA-11 PET-CT and PET-MRI in biochemically recurrent prostate cancer.

AIM: To compare [68Ga]PSMA-11 PET-CT, [68Ga]PSMA-11 PET-MRI and MRI in a cohort of prostate cancer (PCa) patients in biochemical recurrence after initial curative therapy. MATERIALS AND METHODS: Fifty-three patients with biochemically recurrent PCa underwent whole-body [68Ga]PSMA-11 PET-CT 1 hour post-injection (p.i.) followed by [68Ga]PSMA-11 PET-MRI 2.5 hours p.i., including a multiparametric MRI pelvic protocol examination. Imaging data analysis consisted of visual (qualitative) evaluation of the PET-CT, PET-MRI and MRI scans, as well as semi-quantitative and quantitative analyses of the PET and MRI data, including calculation of the parameters standardized uptake value (SUV) and apparent diffusion coefficient (ADC) derived from the PCa lesions. Association analysis was performed between imaging and clinical data, including PSA level and Gleason score. The results were considered significant for p-values less than 0.05 (p < 0.05). RESULTS: The hybrid imaging modalities [68Ga]PSMA-11 PET-CT and PET-MRI were positive in more patients than MRI alone. In particular, PET-CT detected lesions suggestive of PCa relapse in 34/53 (64.2%), PET-MRI in 36/53 (67.9%) and MRI in 23/53 patients (43.4%). While no significant differences in lesion detection rate were observed between PET-CT and PET-MRI, the latter was particularly efficient in detection of local recurrences in the prostate bed mainly due to the contribution of the MRI part of the modality. Association analysis revealed a statistically significant increase in the probability of a positive scan with increasing PSA levels for all imaging modalities. Accordingly, there was no significant association between scan positivity rate and Gleason score for any imaging modality. No significant correlation was observed between SUV and ADC values in lymph node metastases. CONCLUSION: [68Ga]PSMA-11 PET-CT and PET-MRI provide equally good detection rates for PCa recurrence, both outperforming stand-alone MRI.

An R-shiny application to calculate optimal designs for single substance and interaction trials in dose response experiments.

BACKGROUND AND OBJECTIVE: Optimal experimental design theory proposes choosing specific settings in experimental trials in order to maximize the precision of the resulting parameter estimates. In dose response experiments, this corresponds to choosing the optimal dose levels for every available observation, and can be applied both to singular dose-response relationships and to interaction experiments where two substances are given simultaneously at several different mixture ratios ("ray designs"). While the theory of experimental design for this situation is well developed, the mathematical complexity prevents widespread use in practical applications. A simple to use application making the theory accessible to practitioners is thus very desirable. METHODS: Results from established optimal experimental design theory are applied to dose response applications, focusing on log-logistic and Weibull class dose response functions. Suitable optimal design algorithms to solve these problems are implemented into an R-shiny based online application. RESULTS: The application provides an interface to easily calculate D-optimal designs not only for singular dose experiments, but also for interaction trials with several combination rays of substances. Furthermore, the app also allows evaluating the efficiency of existing candidate designs, and finally allows construction of designs which perform robustly under different assumptions in regard to the true parameters.

Assessment of glucose metabolism and cellular proliferation in multiple myeloma: a first report on combined 18F-FDG and 18F-FLT PET/CT imaging.

BACKGROUND: Despite the significant upgrading in recent years of the role of 18F-FDG PET/CT in multiple myeloma (MM) diagnostics, there is a still unmet need for myeloma-specific radiotracers. 3'-Deoxy-3'-[18F]fluorothymidine (18F-FLT) is the most studied cellular proliferation PET agent, considered a potentially new myeloma functional imaging tracer. The aim of this pilot study was to evaluate 18F-FLT PET/CT in imaging of MM patients, in the context of its combined use with 18F-FDG PET/CT. RESULTS: Eight patients, four suffering from symptomatic MM and four suffering from smoldering MM (SMM), were enrolled in the study. All patients underwent 18F-FDG PET/CT and 18F-FLT PET/CT imaging by means of static (whole body) and dynamic PET/CT of the lower abdomen and pelvis (dPET/CT) in two consecutive days. The evaluation of PET/CT studies was based on qualitative evaluation, semi-quantitative (SUV) calculation, and quantitative analysis based on two-tissue compartment modeling. 18F-FDG PET/CT demonstrated focal, 18F-FDG avid, MM-indicative bone marrow lesions in five patients. In contrary, 18F-FLT PET/CT showed focal, 18F-FLT avid, myeloma-indicative lesions in only two patients. In total, 48 18F-FDG avid, focal, MM-indicative lesions were detected with 18F-FDG PET/CT, while 17 18F-FLT avid, focal, MM-indicative lesions were detected with 18F-FLT PET/CT. The number of myeloma-indicative lesions was significantly higher for 18F-FDG PET/CT than for 18F-FLT PET/CT. A common finding was a mismatch of focally increased 18F-FDG uptake and reduced 18F-FLT uptake (lower than the surrounding bone marrow). Moreover, 18F-FLT PET/CT was characterized by high background activity in the bone marrow compartment, further complicating the evaluation of bone marrow lesions. Semi-quantitative evaluation revealed that both SUVmean and SUVmax were significantly higher for 18F-FLT than for 18F-FDG in both MM lesions and reference tissue. SUV values were higher in MM lesions than in reference bone marrow for both tracers. CONCLUSIONS: Despite the limited number of patients analyzed in this pilot study, the first results of the trial indicate that 18F-FLT does not seem suitable as a single tracer in MM diagnostics. Further studies with a larger patient population are warranted to generalize the herein presented results.

68Ga-PSMA PET/CT in the evaluation of bone metastases in prostate cancer.

PURPOSE: The aims of this retrospective analysis were to compare 68Ga-PSMA PET findings and low-dose CT findings (120 kV, 30 mA), and to obtain semiquantitative and quantitative 68Ga-PSMA PET data in patients with prostate cancer (PC) bone metastases. METHODS: In total, 152 PET/CT scans from 140 patients were evaluated. Of these patients, 30 had previously untreated primary PC, and 110 had biochemical relapse after treatment of primary PC. All patients underwent dynamic PET/CT scanning of the pelvis and lower abdomen as well as whole-body PET/CT with 68Ga-PSMA-11. The PET/CT scans were analysed qualitatively (visually), semiquantitatively (SUV), and quantitatively based on a two-tissue compartment model and a noncompartmental approach leading to the extraction of the fractal dimension. Differences were considered significant for p values <0.05. RESULTS: In total, 168 68Ga-PSMA-positive and 113 CT-positive skeletal lesions were detected in 37 patients (8 with primary PC, 29 with biochemical recurrence). Of these 168 lesions, 103 were both 68Ga-PSMA PET-positive and CT-positive, 65 were only 68Ga-PSMA-positive, and 10 were only CT-positive. The Yang test showed that there were significantly more 68Ga-PSMA PET-positive lesions than CT-positive lesions. Association analysis showed that PSA plasma levels were significantly correlated with several 68Ga-PSMA-11-associated parameters in bone metastases, including the degree of tracer uptake (SUVaverage and SUVmax), its transport rate from plasma to the interstitial/intracellular compartment (K1), its rate of binding to the PSMA receptor and its internalization (k3), its influx rate (Ki), and its distribution heterogeneity. CONCLUSION: 68Ga-PSMA PET/CT is a useful diagnostic tool in the detection of bone metastases in PC. 68Ga-PSMA PET visualizes more bone metastases than low-dose CT. PSA plasma levels are significantly correlated with several 68Ga-PSMA PET parameters.

Maximum intensity breast diffusion MRI for BI-RADS 4 lesions detected on X-ray mammography.

AIM: To investigate an abbreviated, contrast-agent free diffusion-weighted (DW) breast magnetic resonance imaging (MRI) protocol that provides a single image for the radiologist to read in order to non-invasively examine Breast Imaging-Reporting and Data System (BI-RADS) 4 lesions detected using breast cancer screening X-ray mammography. MATERIALS AND METHODS: This retrospective evaluation within a institutional review board-approved, prospective study included 115 women (mean 57 years, range 50-69 years) with BI-RADS 4 findings on X-ray mammography and indication for biopsy over a period of 15 months. Full diagnostic breast MRI (FDP) was performed prior to biopsy (1.5 T). Maximum intensity breast diffusion (MIBD) images were generated from DW images (b = 1,500 mm/s2, 3 mm section thickness) of the breast. MIBD and T2-weighted (T2W) images were read by two radiologists and compared to the diagnostic accuracy of an expert reading of the FDP with histopathology as the reference standard. The acquisition time of MIBD and T2W MRI was about 7 minutes. RESULTS: MIBD MRI provided a diagnostic accuracy of 87.93% (95% confidence interval [CI]: 80.58-93.24%) for R1 and 89.66% (95% CI: 82.63-94.54%) for R2. Expert reading of the FDP revealed a similar accuracy of 86.2% (95% CI: 78.67-91.43%). The positive predictive value (PPV) could be increased from 36.2% (95% CI: 28.02-45.28; X-ray mammography alone) to a mean PPV of 80.89% (R1 79.17%, R2 82.16%) using MIBD MRI. Mean reading time was 30 seconds (25%/75 percentile 24.5-41.25). CONCLUSIONS: MIBD MRI might be of supplemental value if added to the work-up of BI-RADS 4 X-ray mammography screening findings. MIBD MRI might help reduce the false-positive rate prior to biopsy for reference lesions at only limited expense of measurement and reading time.

Use of LDH and autoimmune side effects to predict response to ipilimumab treatment.

BACKGROUND: Ipilimumab is a cytotoxic T-lymphocyte antigen-4 antibody that enhances T-cell activity and proliferation. METHODS: In a retrospective analysis of 86 patients the clinical benefits of ipilimumab treatment were correlated with laboratory and clinical data. RESULTS: A lactate dehydrogenase (LDH) value within the normal range before the start of therapy was significantly correlated with better OS (p ≤ 0.009). An increase in LDH level after two cycles was indicative of a poor outcome, and was significantly negatively correlated with treatment response and overall survival and progression-free survival. 42% of all patients suffered from autoimmune toxicity (CTCAE grades 2-4). The occurrence of autoimmune toxicity clearly correlated with clinical benefit. CONCLUSION: Changes in LDH level and side effects correlate with response to therapy and survival.

Comparison of hybrid (68)Ga-PSMA PET/MRI and (68)Ga-PSMA PET/CT in the evaluation of lymph node and bone metastases of prostate cancer.

PURPOSE: To evaluate the reproducibility of the combination of hybrid PET/MRI and the (68)Ga-PSMA-11 tracer in depicting lymph node (LN) and bone metastases of prostate cancer (PC) in comparison with that of PET/CT. MATERIALS AND METHODS: A retrospective analysis of 26 patients who were subjected to (68)Ga-PSMA PET/CTlow-dose (1 h after injection) followed by PET/MRI (3 h after injection) was performed. MRI sequences included T1-w native, T1-w contrast-enhanced, T2-w fat-saturated and diffusion-weighted sequences (DWIb800). Discordant PET-positive and morphological findings were evaluated. Standardized uptake values (SUV) of PET-positive LNs and bone lesions were quantified and their morphological size and conspicuity determined. RESULTS: Comparing the PET components, the proportion of discordant PSMA-positive suspicious findings was very low (98.5 % of 64 LNs concordant, 100 % of 28 bone lesions concordant). Two PET-positive bone metastases could not be confirmed morphologically using CTlow-dose, but could be confirmed using MRI. In 12 of 20 patients, 47 PET-positive LNs (71.9 %) were smaller than 1 cm in short axis diameter. There were significant linear correlations between PET/MRI SUVs and PET/CT SUVs in the 64 LN metastases (p < 0.0001) and in the 28 osseous metastases (p < 0.0001) for SUVmean and SUVmax, respectively. The LN SUVs were significantly higher on PET/MRI than on PET/CT (p SUVmax < 0.0001; p SUVmean < 0.0001) but there was no significant difference between the bone lesion SUVs (p SUVmax = 0.495; p SUVmean = 0.381). Visibility of LNs was significantly higher on MRI using the T1-w contrast-enhanced fat-saturated sequence (p = 0.013), the T2-w fat-saturated sequence (p < 0.0001) and the DWI sequence (p < 0.0001) compared with CTlow-dose. For bone lesions, only the overall conspicuity was higher on MRI compared with CTlow-dose (p < 0.006). CONCLUSION: Nodal and osseous metastases of PC are accurately and reliably depicted by hybrid PET/MRI using (68)Ga-PSMA-11 with very low discordance compared with PET/CT including PET-positive LNs of normal size. The correlation between PET/MRI SUVs and PET/CT SUVs was linear in LN and bone metastases but was significantly lower in control (non-metastatic) tissue.

Cell type-specific expression and localization of cytochrome P450 isoforms in tridimensional aggregating rat brain cell cultures.

Within the Predict-IV FP7 project a strategy for measurement of in vitro biokinetics was developed, requiring the characterization of the cellular model used, especially regarding biotransformation, which frequently depends on cytochrome P450 (CYP) activity. The extrahepatic in situ CYP-mediated metabolism is especially relevant in target organ toxicity. In this study, the constitutive mRNA levels and protein localization of different CYP isoforms were investigated in 3D aggregating brain cell cultures. CYP1A1, CYP2B1/B2, CYP2D2/4, CYP2E1 and CYP3A were expressed; CYP1A1 and 2B1 represented almost 80% of the total mRNA content. Double-immunolabeling revealed their presence in astrocytes, in neurons, and to a minor extent in oligodendrocytes, confirming the cell-specific localization of CYPs in the brain. These results together with the recently reported formation of an amiodarone metabolite following repeated exposure suggest that this cell culture system possesses some metabolic potential, most likely contributing to its high performance in neurotoxicological studies and support the use of this model in studying brain neurotoxicity involving mechanisms of toxication/detoxication.

Selective inhibition of HDAC8 decreases neuroblastoma growth in vitro and in vivo and enhances retinoic acid-mediated differentiation.

For differentiation-defective malignancies, compounds that modulate transcription, such as retinoic acid and histone deacetylase (HDAC) inhibitors, are of particular interest. HDAC inhibitors are currently under investigation for the treatment of a broad spectrum of cancer diseases. However, one clinical drawback is class-specific toxicity of unselective inhibitors, limiting their full anticancer potential. Selective targeting of individual HDAC isozymes in defined tumor entities may therefore be an attractive alternative treatment approach. We have previously identified HDAC family member 8 (HDAC8) as a novel target in childhood neuroblastoma. Using small-molecule inhibitors, we now demonstrate that selective inhibition of HDAC8 exhibits antineuroblastoma activity without toxicity in two xenograft mouse models of MYCN oncogene-amplified neuroblastoma. In contrast, the unselective HDAC inhibitor vorinostat was more toxic in the same models. HDAC8-selective inhibition induced cell cycle arrest and differentiation in vitro and in vivo. Upon combination with retinoic acid, differentiation was significantly enhanced, as demonstrated by elongated neurofilament-positive neurites and upregulation of NTRK1. Additionally, MYCN oncogene expression was downregulated in vitro and tumor cell growth was markedly reduced in vivo. Mechanistic studies suggest that cAMP-response element-binding protein (CREB) links HDAC8- and retinoic acid-mediated gene transcription. In conclusion, HDAC-selective targeting can be effective in tumors exhibiting HDAC isozyme-dependent tumor growth in vivo and can be combined with differentiation-inducing agents.

A sphingosine kinase inhibitor combined with temozolomide induces glioblastoma cell death through accumulation of dihydrosphingosine and dihydroceramide, endoplasmic reticulum stress and autophagy.

Glioblastomas (GBMs) are very aggressive tumors with low chemosensitivity. The DNA-alkylating agent temozolomide (TMZ) is currently the most efficient chemotoxic drug for GBM therapy; however, many patients develop resistance to TMZ. Combining TMZ with another agent could present an improved treatment option if it could overcome TMZ resistance and avoid side effects. Sphingosine kinase inhibitors (SKIs) have emerged as anticancer agents. Sphingosine kinases are often overexpressed in tumors where their activity of phosphorylating sphingosine (Sph) contributes to tumor growth and migration. They control the levels of the pro-apoptotic ceramide (Cer) and Sph and of the pro-survival sphingosine-1 phosphate. In the present work, TMZ was combined with a specific SKI, and the cytotoxic effect of each drug alone or in combination was tested on GBM cell lines. The combination of sublethal doses of both agents resulted in the cell death potentiation of GBM cell lines without affecting astrocyte viability. It triggered a caspase-3-dependent cell death that was preceded by accumulation of dihydrosphingosine (dhSph) and dihydroceramide (dhCer), oxidative stress, endoplasmic reticulum stress, and autophagy. Autophagy was identified as the crucial switch that facilitated induction of this cell death potentiation. The sublethal dose of the inhibitor induced these stress events, whereas that of TMZ induced the destructive autophagy switch. Remarkably, neither Cer nor Sph, but rather the Cer intermediates, dhSph and dhCer, was involved in the cytotoxicity from the combination. Cell lines sensitive to the combination expressed low levels of the antioxidant enzyme glutathione peroxidase-1, indicating this enzyme as a potential marker of sensitivity to such treatment. This work shows for the first time a strong interaction between a SKI and TMZ, leading to a tumor cell-specific death induction. It further demonstrates the biological relevance of dihydrosphingolipids in cell death mechanisms and emphasizes the potential of drugs that affect sphingolipid metabolism for cancer therapy.

Evaluation of the ESUR PI-RADS scoring system for multiparametric MRI of the prostate with targeted MR/TRUS fusion-guided biopsy at 3.0 Tesla.

OBJECTIVES: To evaluate the Prostate Imaging Reporting and Data System (PI-RADS) proposed by the European Society of Urogenital Radiology (ESUR) for detection of prostate cancer (PCa) by multiparametric magnetic resonance imaging (mpMRI) in a consecutive cohort of patients with magnetic resonance/transrectal ultrasound (MR/TRUS) fusion-guided biopsy. METHODS: Suspicious lesions on mpMRI at 3.0 T were scored according to the PI-RADS system before MR/TRUS fusion-guided biopsy and correlated to histopathology results. Statistical correlation was obtained by a Mann-Whitney U test. Receiver operating characteristics (ROC) and optimal thresholds were calculated. RESULTS: In 64 patients, 128/445 positive biopsy cores were obtained out of 95 suspicious regions of interest (ROIs). PCa was present in 27/64 (42%) of the patients. ROC results for the aggregated PI-RADS scores exhibited higher areas under the curve compared to those of the Likert score. Sensitivity/Specificity for the following thresholds were calculated: 85 %/73 % and 67 %/92 % for PI-RADS scores of 9 and 10, respectively; 85 %/60 % and 56 %/97 % for Likert scores of 3 and 4, respectively [corrected. CONCLUSIONS: The standardised ESUR PI-RADS system is beneficial to indicate the likelihood of PCa of suspicious lesions on mpMRI. It is also valuable to identify locations to be targeted with biopsy. The aggregated PI-RADS score achieved better results compared to the single five-point Likert score. KEY POINTS: • The ESUR PI-RADS scoring system was evaluated using multiparametric 3.0-T MRI. • To investigate suspicious findings, transperineal MR/TRUS fusion-guided biopsy was used. • PI-RADS can guide biopsy locations and improve detection of clinically significant cancer. • Biopsy procedures can be optimised, reducing unnecessary negative biopsies for patients. • The PI-RADS scoring system may contribute to more effective prostate MRI.

Comparison of PET/CT and PET/MRI hybrid systems using a 68Ga-labelled PSMA ligand for the diagnosis of recurrent prostate cancer: initial experience.

PURPOSE: (68)Ga-labelled HBED-CC-PSMA is a highly promising tracer for imaging recurrent prostate cancer (PCa). The intention of this study was to evaluate the feasibility of PET/MRI with this tracer. METHODS: Twenty patients underwent PET/CT 1 h after injection of the (68)Ga-PSMA ligand followed by PET/MRI 3 h after injection. Data from the two investigations were first analysed separately and then compared with respect to tumour detection rate and radiotracer uptake in various tissues. To evaluate the quantification accuracy of the PET/MRI system, differences in SUVs between PET/CT and corresponding PET/MRI were compared with differences in SUVs between PET/CT 1 h and 3 h after injection in another patient cohort. This cohort was investigated using the same PET/CT system. RESULTS: With PET/MRI, different diagnostic sequences, higher contrast of lesions and higher resolution of MRI enabled a subjectively easier evaluation of the images. In addition, four unclear findings on PET/CT could be clarified as characteristic of PCa metastases by PET/MRI. However, in PET images of the PET/MRI, a reduced signal was observed at the level of the kidneys (in 11 patients) and around the urinary bladder (in 15 patients). This led to reduced SUVs in six lesions. SUVmean values provided by the PET/MRI system were different in muscles, blood pool, liver and spleen. CONCLUSION: PCa was detected more easily and more accurately with Ga-PSMA PET/MRI than with PET/CT and with lower radiation exposure. Consequently, this new technique could clarify unclear findings on PET/CT. However, scatter correction was challenging when the specific (68)Ga-PSMA ligand was used. Moreover, direct comparison of SUVs from PET/CT and PET/MR needs to be conducted carefully.

Accuracy and variability of semiautomatic centerline analysis versus manual aortic measurement techniques for TEVAR.

OBJECTIVES: This study aims to test whether inter-observer variability and time of diameter measurements for thoracic endovascular aortic repair (TEVAR) are improved by semiautomatic centerline analysis compared to manual assessment. METHODS: Preoperative computed tomography (CT) angiographies of 30 patients with thoracic aortic disease (mean age 66.8 ± 11.6 years, 23 males) were retrospectively analysed by two blinded experts in vascular radiology. Maximum aortic diameters at three positions relevant to TEVAR were assessed (P1, distal to left common carotid artery; P2, distal to left subclavian artery; and P3, proximal to coeliac trunk) using three measurement techniques: manual axial slices (axial), manual double-oblique multiplanar reformations (MPRs) and semiautomatic centerline analysis. RESULTS: Diameter measurements by both centerline analysis and the axial technique did not significantly differ from MPR (p = 0.17 and p = 0.37). Total deviation index for 0.9 was for P1 2.7 mm (axial), 3.7 mm (MPR), 1.8 mm (centerline); for P2 2.0 mm (axial), 3.6 mm (MPR), 1.8 mm (centerline); and for P3 3.0 mm (axial), 3.5 mm (MPR), 2.5 mm (centerline). Measurement time using centerline analysis was significantly shorter than for assessment by MPR. CONCLUSIONS: Centerline analysis provides the least variable and fast diameter measurements in TEVAR patients with the same accuracy as the current reference standard MPR.

The value of selected in vitro and in silico methods to predict acute oral toxicity in a regulatory context: results from the European Project ACuteTox.

ACuteTox is a project within the 6th European Framework Programme which had as one of its goals to develop, optimise and prevalidate a non-animal testing strategy for predicting human acute oral toxicity. In its last 6 months, a challenging exercise was conducted to assess the predictive capacity of the developed testing strategies and final identification of the most promising ones. Thirty-two chemicals were tested blind in the battery of in vitro and in silico methods selected during the first phase of the project. This paper describes the classification approaches studied: single step procedures and two step tiered testing strategies. In summary, four in vitro testing strategies were proposed as best performing in terms of predictive capacity with respect to the European acute oral toxicity classification. In addition, a heuristic testing strategy is suggested that combines the prediction results gained from the neutral red uptake assay performed in 3T3 cells, with information on neurotoxicity alerts identified by the primary rat brain aggregates test method. Octanol-water partition coefficients and in silico prediction of intestinal absorption and blood-brain barrier passage are also considered. This approach allows to reduce the number of chemicals wrongly predicted as not classified (LD50>2000 mg/kg b.w.).

Comparative analysis of eight cytotoxicity assays evaluated within the ACuteTox Project.

A comparative analysis of eight cytotoxicity assays [the 3T3 and normal human keratinocytes Neutral Red Uptake (NRU) assay, the primary rat hepatocytes, human HepG2 and 3T3 MTT assay, and the human A.704, SH-SY5Y and HepG2 cells propidium iodide (PI) assay] included in several work packages of the EU Integrated Project ACuteTox, has been carried out. The aim was to evaluate whether cells originating from liver, kidney and brain provided different in vitro acute toxicity results, and the influence of primary liver cells versus cell lines originated from the same tissue. Spearman rank correlation analysis and Hierarchical Cluster Analysis were performed based on the IC50 (50% inhibitory concentrations for the endpoint measured) values generated for 57 chemicals. A relatively large number of neurotoxicants and hepatotoxicants were included which allowed to examine the impact of chemicals with specific tissue toxicity on the results. Our analyses confirmed the similarity between the NRU assays and between the two hepatic cell systems related MTT assays. The type of assay appears to have the greatest influence upon the clustering result regardless of the origin of the cells used. The information provided by the NRU and MTT assays differed from that provided by the PI assay. This approach did not allow to show tissue specific toxicity but it does reveal the effectiveness of the clustering methodology for choosing assays for a testing program for predicting e.g. acute oral toxicity in humans.

Selection of test methods to be included in a testing strategy to predict acute oral toxicity: an approach based on statistical analysis of data collected in phase 1 of the ACuteTox project.

More than 50 different in vitro and in silico methods assessing specific organ- and system-toxicity, such as haemato-, neuro-, nephro- and hepatotoxicity, as well as intestinal absorption, distribution and metabolism, have been used in the first phase of the ACuteTox project to test a common set of 57 chemicals. This paper describes the methods used for statistical evaluation of concentration-response data collected for each of the endpoint assays, and for the development of a testing strategy applicable for acute toxicity classification of chemicals based on the achieved results of the concentration-response analysis. A final list of in vitro test methods considered to be promising candidates for building blocks of the testing strategy is presented. Only these selected test methods were further investigated in the prevalidation phase of the project. The test methods were chosen according to their reproducibility and reliability and most importantly, according to their potential to classify chemicals into the official acute oral toxicity categories of the EU Classification, Labelling and Packaging (CLP) Regulation. The potential of the test methods to correctly classify the chemicals was assessed by Classification and Regression Trees (CART) analysis.

Diffusion-weighted imaging in rectal carcinoma patients without and after chemoradiotherapy: a comparative study with histology.

Diffusion-weighted imaging (DWI) can be used to quantitatively assess functional parameters in rectal carcinoma that are relevant for prognosis and treatment response assessment. However, there is no consensus on the histopathological background underlying the findings derived from DWI. The aim of this study was to perform a comparison of DWI and histologic parameters in two groups of rectal carcinoma patients without (n=12) and after (n=9) neoadjuvant chemoradiotherapy (CRT). The intravoxel incoherent motion (IVIM) model was used to calculate the diffusion coefficient D and the perfusion fraction f in rectal carcinoma, the adjacent rectum and fat in the two patient groups. Immunohistological analysis was performed to assess the cellularity, vascular area fraction and vessel diameter for comparison and correlation. Out of 36 correlations between parameters from DWI and histology, four were found to be significant. In rectal carcinoma of patients without CRT, the diffusion D and the perfusion f correlated with the vascular area fraction, respectively, which could not be found in the group of patients who received CRT. Further correlations were found for the rectum and fat. Histological evaluation revealed significant differences between the tissues on the microscopic level concerning the cellular and vascular environment that influence diffusion and perfusion. In conclusion, DWI produces valuable biomarkers for diffusion and perfusion in rectal carcinoma and adjacent tissues that are highly dependent of the underlying cellular microenvironment influenced by structural and functional changes as well as the administered treatment, and consequently can be beyond histological ascertainability.

Toxicogenomic analysis of N-nitrosomorpholine induced changes in rat liver: comparison of genomic and proteomic responses and anchoring to histopathological parameters.

A common animal model of chemical hepatocarcinogenesis was used to examine the utility of transcriptomic and proteomic data to identify early biomarkers related to chemically induced carcinogenesis. N-nitrosomorpholine, a frequently used genotoxic model carcinogen, was applied via drinking water at 120 mg/L to male Wistar rats for 7 weeks followed by an exposure-free period of 43 weeks. Seven specimens of each treatment group (untreated control and 120 mg/L N-nitrosomorpholine in drinking water) were sacrificed at nine time points during and after N-nitrosomorpholine treatment. Individual samples from the liver were prepared for histological and toxicogenomic analyses. For histological detection of preneoplastic and neoplastic tissue areas, sections were stained using antibodies against the placental form of glutathione-S-transferase (GST-P). Gene and protein expression profiles of liver tissue homogenates were analyzed using RG-U34A Affymetrix rat gene chips and two-dimensional gel electrophoresis-based proteomics, respectively. In order to compare results obtained by histopathology, transcriptomics and proteomics, GST-P-stained liver sections were evaluated morphometrically, which revealed a parallel time course of the area fraction of preneoplastic lesions and gene plus protein expression patterns. On the transcriptional level, an increase of hepatic GST-P expression was detectable as early as 3 weeks after study onset. Comparing deregulated genes and proteins, eight species were identified which showed a corresponding expression profile on both expression levels. Functional analysis suggests that these genes and corresponding proteins may be useful as biomarkers of early hepatocarcinogenesis.

Semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma stage III/IV--a feasibility study.

Therapy monitoring in oncological patient care requires accurate and reliable imaging and post-processing methods. RECIST criteria are the current standard, with inherent disadvantages. The aim of this study was to investigate the feasibility of semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma compared to manual volumetric analysis and RECIST. Multislice CT was performed in 47 patients, covering the chest, abdomen and pelvis. In total, 227 suspicious, enlarged lymph nodes were evaluated retrospectively by two radiologists regarding diameters (RECIST), manually measured volume by placement of ROIs and semi-automated volumetric analysis. Volume (ml), quality of segmentation (++/--) and time effort (s) were evaluated in the study. The semi-automated volumetric analysis software tool was rated acceptable to excellent in 81% of all cases (reader 1) and 79% (reader 2). Median time for the entire segmentation process and necessary corrections was shorter with the semi-automated software than by manual segmentation. Bland-Altman plots showed a significantly lower interobserver variability for semi-automated volumetric than for RECIST measurements. The study demonstrated feasibility of volumetric analysis of lymph node metastases. The software allows a fast and robust segmentation in up to 80% of all cases. Ease of use and time needed are acceptable for application in the clinical routine. Variability and interuser bias were reduced to about one third of the values found for RECIST measurements.

[Gait analysis in limb-preserving tumour surgery--kinematic gait patterns after resection of malignant bone tumours near the knee joint]. / Ganganalyse bei extremitätenerhaltender Tumorchirurgie--Vergleich der Bewegungsmuster nach Resektion primär maligner Tumoren im Bereich des Kniegelenkes.

AIM: Limb-preserving surgery is the most common therapeutic approach in cases of malignant bone tumours near the knee joint. Although good functional results have been reported for tumours located in the distal femur, tumours in the proximal tibia have been investigated less frequently. The objective of the current study was to compare the kinematic gait patterns in patients with tumours in the femur vs. the tibia. METHOD: 11 patients with an arthroplasty after a primary malignant bone tumour were included (5 femur, 6 tibia). Their speed-specific kinematic gait patterns were quantified. 10 healthy volunteers and 6 patients with normal knee arthroplasty served as a reference group. RESULTS: The tibia patients walked significantly more slowly than the femur patients. They showed a similar overall gait pattern predominantly characterised by a hyperextended knee during stance. CONCLUSION: The differences in walking speed between the two groups of tumour patients did not transfer to different gait patterns. Limb-preserving surgery is thus a valuable therapeutic option also for patients with primary tumours in the tibia.