DCAF11 Supports Targeted Protein Degradation by Electrophilic Proteolysis-Targeting Chimeras.

Ligand-induced protein degradation has emerged as a compelling approach to promote the targeted elimination of proteins from cells by directing these proteins to the ubiquitin-proteasome machinery. So far, only a limited number of E3 ligases have been found to support ligand-induced protein degradation, reflecting a dearth of E3-binding compounds for proteolysis-targeting chimera (PROTAC) design. Here, we describe a functional screening strategy performed with a focused library of candidate electrophilic PROTACs to discover bifunctional compounds that degrade proteins in human cells by covalently engaging E3 ligases. Mechanistic studies revealed that the electrophilic PROTACs act through modifying specific cysteines in DCAF11, a poorly characterized E3 ligase substrate adaptor. We further show that DCAF11-directed electrophilic PROTACs can degrade multiple endogenous proteins, including FBKP12 and the androgen receptor, in human prostate cancer cells. Our findings designate DCAF11 as an E3 ligase capable of supporting ligand-induced protein degradation via electrophilic PROTACs.

Psychodynamic interventions in cancer care I: psychometric results of a randomized controlled trial.

OBJECTIVE: This study aimed to assess the effectiveness of psychodynamic interventions in cancer care. METHODS: Between 2006 and 2009, each consecutive outpatient of the Oncology Center of the University Hospital of Lausanne was invited to participate in a trial evaluating the effects of psychological support. Accepting patients were randomly assigned to an immediate intervention or a delayed intervention [4-month waiting list]. Patients who declined support were asked to participate in an observational group [OG]. Socio-demographic and medical data, anxiety, and depression [HADS], psychological distress [SCL-90], alexithymia [TAS] and quality of life [EORTC] were recorded at baseline, and at 1, 4, 8, and 12-months follow-up. RESULTS: Of the 1973 approached patients, 1057 were excluded, 530 refused, and 386 were included with 196 of them participating in the OG. Of the patients in the intervention group [IG] [N = 190], 94 were randomized to the immediate intervention and 96 to the delayed intervention group (dIG). IG patients were younger, predominantly female, and had more psychological symptoms compared with those in the OG. Although patients of the IG and OG showed significant improvement in quality of life from baseline to 12-months follow-up, other outcomes [anxiety, depression, psychological distress, and alexithymia] remained unchanged. CONCLUSIONS: The intervention was not effective with regards to psychometric outcome. The results have to be interpreted in light of the study design [untargeted intervention], the low levels of psychiatric symptoms, dropout of symptomatic patients, and the high prevalence of alexithymia.

Blood eosinophil and platelet levels, proteomics patterns of trail and CXCL8 correlated with survival in bevacizumab treated metastatic colon cancers.

STrail (soluble TNF-related apoptosis-inducing-ligand) has also been observed where the cytotoxic effects of antiangiogenic agents are increased in clinical phase II and III studies when these agents are combined with TRAIL related therapies. Recent studies have shown that CXCL8 and its receptors are significantly up-regulated in CRC and act as regulators of proliferation, angiogenesis, and metastasis. sTRAIL, CXCL8, CEA, together with complete blood count parameters (hemoglobine, platelet, eosinophil, basophil, neutrophil, lymphocyte) were recorded in the beginning and every three months afterwards for a period of 4 years. The study population comprised 21 of the 42 patients with metastatic colorectal cancer (MCRC), undergoing 18 FDG-PET/CT scanning prior to treatment. Progression free survival was 262 days and overall survival was 1148 days. Overall survival was higher in patients whose Karnofsky Performance scores were above 86% (p = 0.003). Progression free survival was higher in patients whose blood eosinophil counts at 0, 6, and 9 months were higher than the mean levels of corresponding values (p-values are 0.016, 0.032, and 0.001, respectively). Another significant positive correlation was found between the platelet levels at 9 months and progression free survival (p = 0.019). There were significant changes (p < 0.05) prior to treatment and three months later for sTRAIL (p = 0.0060) and CXCL8 (p = 0.00001), based on the Wilcoxon matched pairs signed rank test. Generally, sTRAIL values increased during therapy, while a decrease was observed for CXCL8 without any significant differences for other variables.

Application of F-18-sodium fluoride (NaF) dynamic PET-CT (dPET-CT) for defect healing: a comparison of biomaterials in an experimental osteoporotic rat model.

BACKGROUND: The aim of the current study was to measure and compare the effect of various biomaterials for the healing of osteoporotic bone defects in the rat femur using 18F-sodium fluoride dPET-CT. MATERIAL AND METHODS: Osteoporosis was induced by ovariectomy and a calcium-restricted diet. After 3 months, rats were operated on to create a 4-mm wedge-shaped defect in the distal metaphyseal femur. Bone substitution materials of calcium phosphate cement (CPC), composites of collagen and silica, and iron foams with interconnecting pores were inserted. Strontium or bisphosphonate, which are well known for having positive effects in osteoporosis treatment, were added into the materials. Eighteen weeks after osteoporosis induction and 6 weeks following femoral surgery, dPET-CT studies scan were performed with 18F-Sodium Fluoride. Standardized uptake values (SUVs) and a 2-tissue compartmental learning-machine model (K1-k4, vessel density [VB], influx [ki]) were used for quantitative analysis. RESULTS: k3, reflecting the formation of fluoroapatite, revealed a statistically significant increase at the biomaterial-bone interface due to the Sr release from strontium-modified calcium phosphate cement (SrCPC) compared to CPC, which demonstrated enhanced new bone formation. In addition, k3 as measured in the porous scaffold silica/collagen xerogel (Sc-B30), showed a significant increase based on Wilcoxon rank-sum test (p<0.05) as compared with monolithic silica/collagen xerogel (B30) in the defect region. Furthermore, ki, reflecting the net plasma clearance of tracer to bone mineral measured in the iron foam with coating of the bisphosphonate zoledronic acid (Fe-BP), was enhanced as compared with plain iron foam (Fe) in the defect region. CONCLUSIONS: k3 was the most significant parameter for the characterization of healing processes and revealed the best differentiation between the 2 different biomaterials. PET scanning using 18F-sodium fluoride seems to be a sensitive and useful method for evaluation of bone healing after replacement with these biomaterials.

Paralogue-Selective Degradation of the Lysine Acetyltransferase EP300.

The transcriptional coactivators EP300 and CREBBP are critical regulators of gene expression that share high sequence identity but exhibit nonredundant functions in basal and pathological contexts. Here, we report the development of a bifunctional small molecule, MC-1, capable of selectively degrading EP300 over CREBBP. Using a potent aminopyridine-based inhibitor of the EP300/CREBBP catalytic domain in combination with a VHL ligand, we demonstrate that MC-1 preferentially degrades EP300 in a proteasome-dependent manner. Mechanistic studies reveal that selective degradation cannot be predicted solely by target engagement or ternary complex formation, suggesting additional factors govern paralogue-specific degradation. MC-1 inhibits cell proliferation in a subset of cancer cell lines and provides a new tool to investigate the noncatalytic functions of EP300 and CREBBP. Our findings expand the repertoire of EP300/CREBBP-targeting chemical probes and offer insights into the determinants of selective degradation of highly homologous proteins.

Unexpected Noncovalent Off-Target Activity of Clinical BTK Inhibitors Leads to Discovery of a Dual NUDT5/14 Antagonist.

Cofactor mimicry represents an attractive strategy for the development of enzyme inhibitors but can lead to off-target effects due to the evolutionary conservation of binding sites across the proteome. Here, we uncover the ADP-ribose (ADPr) hydrolase NUDT5 as an unexpected, noncovalent, off-target of clinical BTK inhibitors. Using a combination of biochemical, biophysical, and intact cell NanoBRET assays as well as X-ray crystallography, we confirm catalytic inhibition and cellular target engagement of NUDT5 and reveal an unusual binding mode that is independent of the reactive acrylamide warhead. Further investigation of the prototypical BTK inhibitor ibrutinib also revealed potent inhibition of the largely unstudied NUDIX hydrolase family member NUDT14. By exploring structure-activity relationships (SARs) around the core scaffold, we identify a potent, noncovalent, and cell-active dual NUDT5/14 inhibitor. Cocrystallization experiments yielded new insights into the NUDT14 hydrolase active site architecture and inhibitor binding, thus providing a basis for future chemical probe design.

A case of toxic epidermal necrolysis with diverse etiologies: successful treatment with intravenous immunoglobulin and pulse prednisolone and effects on sTRAIL and sCD200 levels.

BACKGROUND: Here, we report the first case of patient with intracranial tumors (ICT) who developed a cutaneous adverse drug reaction during lansoprazole and prophylactic anticonvulsant treatment. SCORTEN is a scoring system used to predict mortality in TEN patients. If SCORTEN index is 5 or more, mortality rate is more than 90%. SCORTEN of our patient was calculated as 5. METHODS: Our patient is a 64 year-old white female, who had glioma and had been on post-op prophylactic anticonvulsant therapy. On the 3rd day post operation, lansoprazole was added to the therapy. After the first lansoprazole dose, erythematous dusky red macules occurred on extremities and trunk and on the following day confluent purpuric lesions tended to run together in 95% of the whole body including scalp, oral and genital mucosa. Nikolsky's Sign was positive on the skin. Physical examination; body temperature was 38.4 degrees C with a heart rate of 146 beats/minute and 80/50 mm Hg arterial blood pressure, Glascow Coma Scale was E1 M1e, pupillary light reflex was 2/2 +/+ and she was confused. Her biopsy resulted as toxic epidermal necrolysis. Moreover, sTRAIL and sCD200 levels of serum and blister fluid were investigated as an apoptotic marker and a negative marker for inflammation. RESULTS AND CONCLUSIONS: sTRAIL and sCD200 were evaluated both in the sera and blister fluid. sTRAIL level was lower than for healthy individuals with high levels in blister fluid; and sCD200 level was depressed by up to 10% of the normal values of healthy individuals but with high levels in the blister fluid during the active phase of the disease. After our successful treatment with human albumin, prednisolone pulse therapy, and IVIG at a dose of 400 mg/kg, she was discharged from the hospital on the 23rd day and followed up after 2 months. The increase in sTRAIL (up to two-fold) and sCD200 (up to six-fold) levels may provide useful information in understanding disease pathogenesis and monitoring treatment efficacy.

Level of TNF-related apoptosis-inducing-ligand and CXCL8 correlated with 2-[18F]Fluoro-2-deoxy-D-glucose uptake in anti-VEGF treated colon cancers.

BACKGROUND: The changes and correlations of TRAIL (TNF-related apoptosis-inducing-ligand) and CXCL8 (IL8) prior to treatment and three months following therapy as well as the corresponding Positron emission tomography (PET/CT) (SUV(max): standardized uptake maximum values) results were evaluated. MATERIAL AND METHODS: The measurements were taken before and after treatment for comparison purposes. The study population comprised 29 patients with Metastatic Colorectal cancer (MCRC), undergoing PET/CT scanning prior to treatment. RESULTS: There were significant changes prior to treatment and three months later for sTRAIL (p=0.0080) and CXCL8 (p=0.0001)values. Generally, sTRAIL values were increasing during therapy, while a decrease was observed for CXCL8. Correlation analysis was applied to the data and revealed significant correlations for the SUV(max) in the primary tumor prior to treatment and CXCL8 prior to therapy (p=0.0303). Furthermore, significant correlations were observed for the SUV(max) and sTRAIL (p=0.0237) as well as CXCL8 (p=0.0002) three months after treatment initiation. CXCL8 prior to treatment was also correlated with the SUV three months after onset of treatment (p=0.0072). A significant correlation was noted for one combination of two variables, the SUV(max) in the metastases and CXCL8 prior to treatment (p=0.0175). These results are supported when we group the SUV(max) in the metastases following treatment into two groups with SUV(max) <5 and SUV(max) >5. CONCLUSIONS: This study provides evidence that proteomics patterns of sTRAIL and CXCL8 predict tumor response und survival in MCRC patients treated with bevacizumab and within a high concordance of FDG-PET/CT findings.

Effects of omalizumab on eosinophil cationic peptide, 25-hydroxyvitamin-D, IL-1ß and sCD200 in cases of Samter's syndrome: 36 months follow-up.

CONTEXT: The historic triad of nasal polyposis, asthma and intolerance to aspirin and related chemicals, recently designated as Samter's syndrome, is an inflammatory condition of unknown pathogenesis. This study surveyed the levels of chosen serum eosinophil cationic peptide (ECP), soluble CD200 (SCD200), interleukin (IL)-1ß, high sensitive C-reactive protein (hs-CRP) and 25-hydroxyvitamin-D (25(OH)D) in the aspirin-induced asthmatic patients treated with anti-IgE therapy to investigate their roles in the pathogenesis of disease perpetuation and anti-IgE therapy's impact on them. METHODS: Medical history, lung function tests and measurement of fractional exhale nitric oxide concentrations were performed on the same day. Concentrations of IL-1ß and SCD200 in the serum samples were quantified using ELISA kits. Total and specific IgE and hs-CRP levels were enumerated by fluoroenzyme immunoassay. Serum levels of 25(OH)D were quantified by a radioimmunoassay. RESULTS: We had three patients of severe persistent allergic asthma with Samter's syndrome. Levels of total IgE, ECP, fractional exhale nitric oxide concentrations, SCD200, IL-1ß and hs-CRP were decreased while 25(OH)D was increased after starting the treatment of anti-IgE. CONCLUSIONS: To our knowledge, this is the first time an association between omalizumab use and Samter's syndrome has been documented. As a conclusion allergic nasal symptoms (sneezing, postnasal drip) and asthma symptoms were decreased in patients, but no change was seen on nasal polyposis development after omalizumab treatment.

Target deconvolution with matrix-augmented pooling strategy reveals cell-specific drug-protein interactions.

Target deconvolution is a crucial but costly and time-consuming task that hinders large-scale profiling for drug discovery. We present a matrix-augmented pooling strategy (MAPS) which mixes multiple drugs into samples with optimized permutation and delineates targets of each drug simultaneously with mathematical processing. We validated this strategy with thermal proteome profiling (TPP) testing of 15 drugs concurrently, increasing experimental throughput by 60x while maintaining high sensitivity and specificity. Benefiting from the lower cost and higher throughput of MAPS, we performed target deconvolution of the 15 drugs across 5 cell lines. Our profiling revealed that drug-target interactions can differ vastly in targets and binding affinity across cell lines. We further validated BRAF and CSNK2A2 as potential off-targets of bafetinib and abemaciclib, respectively. This work represents the largest thermal profiling of structurally diverse drugs across multiple cell lines to date.

Correlation of dynamic PET and gene array data in patients with gastrointestinal stromal tumors.

INTRODUCTION: The results obtained with dynamic PET (dPET) were compared to gene expression data obtained in patients with gastrointestinal stromal tumors (GIST). The primary aim was to assess the association of the dPET results and gene expression data. MATERIAL AND METHODS: dPET was performed following the injection of F-18-fluorodeoxyglucose (FDG) in 22 patients with GIST. All patients were examined prior to surgery for staging purpose. Compartment and noncompartment models were used for the quantitative evaluation of the dPET examinations. Gene array data were based on tumor specimen obtained by surgery after the PET examinations. RESULTS: The data analysis revealed significant correlations for the dPET parameters and the expression of zinc finger genes (znf43, znf85, znf91, znf189). Furthermore, the transport of FDG (k1) was associated with VEGF-A. The cell cycle gene cyclin-dependent kinase inhibitor 1C was correlated with the maximum tracer uptake (SUVmax) in the tumors. CONCLUSIONS: The data demonstrate a dependency of the tracer kinetics on genes associated with prognosis in GIST. Furthermore, angiogenesis and cell proliferation have an impact on the tracer uptake.

Incidental detection and monitoring of spontaneous recovery of sarcoidosis via fluorine-18-fluoroethyl-choline positron emission tomography/computed tomography.

We report a case of sarcoidosis detected incidentally by using fluorine-18-fluoroethylcholine- positron emission tomography/computed tomography (¹8F-FECH-PET/CT) in a 72 years old patient with prostate cancer, who had been referred for restaging after relapse indicated prostate specific antigen (PSA). The ¹8F-FECH-PET/CT examination showed a focal increased uptake in the prostate bed suggestive for local recurrence, in addition to multifocal uptake in the mediastinum matching with enlarged hilar and paratracheal lymph nodes. Histopathology revealed sarcoidosis. No treatment was recommended. Two years later the patient was referred again to us because of another recurrent PSA elevation. The second ¹8F-FECH-PET/CT showed again the previously described local recurrence, but did not show the previously described mediastinal findings nor the enlarged hilar and paratracheal lymph nodes, thus, illustrating spontaneous healing of sarcoidosis. In conclusion, this case suggests that ¹8F-FECH PET/CT study can show positive findings in sarcoidosis that were no longer detectable after two years, suggestive of spontaneous recovery.

[Altruistic kidney donation: psychological challenges]. / Don de rein altruiste: enjeux psychologiques.

Altruistic kidney donation challenges ethical principles, questions the anthropological meaning of donation and is associated with important psychological aspects. Obtaining free and informed consent is essential and requires a depth evaluation by a psychologist or a psychiatrist in order to identify the motivations which stimulate the desire of donation. By means of a psychodynamic understanding of a clinical case, we illustrate the complexity of the evaluation of consent and discuss the psychological issues associated with altruistic kidney donation.

Parametric images via dynamic 18F-fluorodeoxyglucose positron emission tomographic data acquisition in predicting midterm outcome of liver metastases secondary to gastrointestinal stromal tumours.

PURPOSE: (18)F-Fluorodeoxyglucose positron emission tomography (FDG PET) may underestimate viable tumour tissue in patients with gastrointestinal stromal tumours (GIST) treated with molecular targeted agents. The aim of the present study was to investigate the value of parametric images generated after dynamic data acquisition for the detection of active liver metastases. METHODS: The analysis included 65 dynamic FDG PET studies in 34 patients with liver metastases from GIST who were treated with imatinib or sunitinib. Parametric images of intercept and slope were calculated by dedicated software using a voxel-based linear regression of time-activity data. Intercept images represent the tracer's distribution volume and the slope its overall metabolic turnover. All images were assessed visually and semi-quantitatively. Liver disease status was established 12 months after each PET study. Dichotomous variables of visual interpretation and various quantitative parameters were entered in a statistical model of linear discriminant analysis. RESULTS: Visual analysis of slope images was more sensitive than the standard 1-h FDG uptake evaluation (70.6 vs 51.0%, p = 0.016) in detecting cases with liver disease progression (n = 51). Specificity did not differ. Combination of all variables in the discriminant analysis model correctly classified 87.7% of cases as progressive or non-progressive disease. Sensitivity was raised to 88.2%. CONCLUSION: Parametric images of intercept and slope add a new dimension to the interpretation of FDG PET studies, by isolating visually and quantifying the perfusion and phosphorylation-dependent part of tracer uptake. In treated GIST patients, integration of this information with the 1-h uptake data achieves better characterization of hepatic lesions with respect to disease activity.

A phase II study evaluating neo-/adjuvant EIA chemotherapy, surgical resection and radiotherapy in high-risk soft tissue sarcoma.

BACKGROUND: The role of chemotherapy in high-risk soft tissue sarcoma is controversial. Though many patients undergo initial curative resection, distant metastasis is a frequent event, resulting in 5-year overall survival rates of only 50-60%. Neo-adjuvant and adjuvant chemotherapy (CTX) has been applied to achieve pre-operative cytoreduction, assess chemosensitivity, and to eliminate occult metastasis. Here we report on the results of our non-randomized phase II study on neo-adjuvant treatment for high-risk STS. METHOD: Patients with potentially curative high-risk STS (size ≥ 5 cm, deep/extracompartimental localization, tumor grades II-III [FNCLCC]) were included. The protocol comprised 4 cycles of neo-adjuvant chemotherapy (EIA, etoposide 125 mg/m(2) iv days 1 and 4, ifosfamide 1500 mg/m2 iv days 1 - 4, doxorubicin 50 mg/m(2) day 1, pegfilgrastim 6 mg sc day 5), definitive surgery with intra-operative radiotherapy, adjuvant radiotherapy and 4 adjuvant cycles of EIA. RESULT: Between 06/2005 and 03/2010 a total of 50 subjects (male = 33, female = 17, median age 50.1 years) were enrolled. Median follow-up was 30.5 months. The majority of primary tumors were located in the extremities or trunk (92%), 6% originated in the abdomen/retroperitoneum. Response by RECIST criteria to neo-adjuvant CTX was 6% CR (n = 3), 24% PR (n = 12), 62% SD (n = 31) and 8% PD (n = 4). Local recurrence occurred in 3 subjects (6%). Distant metastasis was observed in 12 patients (24%). Overall survival (OS) and disease-free survival (DFS) at 2 years was 83% and 68%, respectively. Multivariate analysis failed to prove influence of resection status or grade of histological necrosis on OS or DFS. Severe toxicities included neutropenic fever (4/50), cardiac toxicity (2/50), and CNS toxicity (4/50) leading to CTX dose reductions in 4 subjects. No cases of secondary leukemias were observed so far. CONCLUSION: The current protocol is feasible for achieving local control rates, as well as OS and DFS comparable to previously published data on neo-/adjuvant chemotherapy in this setting. However, the definitive role of chemotherapy remains unclear in the absence of large, randomized trials. Therefore, the current regimen can only be recommended within a clinical study, and a possibly increased risk of secondary leukemias has to be taken into account. TRIAL REGISTRATION: ClinicalTrials.gov NCT01382030, EudraCT 2004-002501-72.

Positron emission tomography in patients with aggressive fibromatosis/desmoid tumours undergoing therapy with imatinib.

PURPOSE: We used (18)F-FDG PET to evaluate the FDG uptake in patients with aggressive fibromatosis (AF, also known as desmoid tumours) undergoing therapy with imatinib (imatinib mesylate, Glivec). METHODS: The pilot study included nine patients with progressive AF receiving oral treatment with imatinib at a daily dose of 800 mg. Patients were examined using PET prior to the start of therapy and during imatinib treatment. Restaging according to the Response Evaluation Criteria in Solid Tumors (RECIST) was performed in parallel using CT and/or MRI and served as reference. RESULTS: The clinical outcomes in nine evaluable patients were as follows: seven patients with stable disease, and two patients with progressive disease. A 27% decrease in the median average standardized uptake value (SUV) of the sequential PET examinations was demonstrated in all evaluable patients with three patients (33%) showing a decrease in SUV of more than 40% (48%, 52% and 54%, respectively); no patient showed a substantial increase in SUV. CONCLUSION: To our knowledge, this is the first series of AF patients undergoing treatment with imatinib and monitored using sequential PET imaging, that allows detection of SUV changes after imatinib induction, thus helping to decide whether treatment should be continued or not.

Prediction of chemotherapy outcome in patients with metastatic soft tissue sarcomas based on dynamic FDG PET (dPET) and a multiparameter analysis.

PURPOSE: Dynamic PET studies with (18)F-FDG were performed in patients with metastatic soft tissue sarcomas who received conventional chemotherapy with doxorubicin hydrochloride (Adriamycin) and ifosfamide (AI-G). The goal of the study was to evaluate the impact of full kinetic analysis and assess its value with regard to the therapy outcome based on survival data. METHODS: The evaluation included 17 patients with 29 metastatic lesions of soft tissue sarcomas, who were treated with chemotherapy consisting of an AI-G regimen prior to high-dose chemotherapy and peripheral blood stem cell transplantation where applicable. Patients were examined prior to onset of therapy and after completion of the first cycle of AI-G. Restaging data (n = 17) based on Response Evaluation Criteria in Solid Tumors were available. Survival data (n = 14) served for reference. The following parameters were retrieved from the dynamic PET studies: standardized uptake value (SUV), fractal dimension, two-compartment model with computation of k1, k2, k3, k4 (unit: 1/min), the fractional blood volume and the FDG influx calculated according to Patlak. RESULTS: The mean SUV was 6.9 prior to therapy and 4.7 after one cycle. The mean influx was 0.066 prior to therapy in comparison to 0.058 after one cycle. We dichotomized the patients according to the median survival time of 320 days into response (n = 6) and non-response (n = 8). The mean SUV was 7.6 in the group of responders and 5.4 in the group of non-responders prior to therapy. Responders revealed a mean SUV of 3.8 after therapy as compared to 5.0 SUV for non-responders. We used discriminant analysis to classify the patients into the two response groups. The classification of the non-responders was generally higher (negative predictive value > 61%) than for the responders. Finally, the combined use of the four predictor variables, namely mean SUV and k1 of both studies led to the highest accuracy of 90% for both groups. CONCLUSION: The data demonstrate that only a multiparameter analysis based on a combination of the absolute values of mean SUV and k1 of a baseline study and a follow-up study after completion of one cycle was the best combination for a group-based analysis, into response or non-response. The quantitative assessment of the FDG kinetics in tumours should be used to quantify the "inhibitory effect" of chemotherapy and to individualize treatment. The main effect of the AI-G therapy may be on angiogenesis (k1 effect) rather than on proliferation.

Top predators, mesopredators and their prey: interference ecosystems along bioclimatic productivity gradients.

1. The Mesopredator Release Hypothesis (MRH) suggests that top predator suppression of mesopredators is a key ecosystem function with cascading impacts on herbivore prey, but it remains to be shown that this top-down cascade impacts the large-scale structure of ecosystems. 2. The Exploitation Ecosystems Hypothesis (EEH) predicts that regional ecosystem structures are determined by top-down exploitation and bottom-up productivity. In contrast to MRH, EEH assumes that interference among predators has a negligible impact on the structure of ecosystems with three trophic levels. 3. We use the recolonization of a top predator in a three-level boreal ecosystem as a natural experiment to test if large-scale biomass distributions and population trends support MRH. Inspired by EEH, we also test if top-down interference and bottom-up productivity impact regional ecosystem structures. 4. We use data from the Finnish Wildlife Triangle Scheme which has monitored top predator (lynx, Lynx lynx), mesopredator (red fox, Vulpes vulpes) and prey (mountain hare, Lepus timidus) abundance for 17 years in a 200 000 km(2) study area which covers a distinct productivity gradient. 5. Fox biomass was lower than expected from productivity where lynx biomass was high, whilst hare biomass was lower than expected from productivity where fox biomass was high. Hence, where interference controlled fox abundance, lynx had an indirect positive impact on hare abundance as predicted by MRH. The rates of change indicated that lynx expansion gradually suppressed fox biomass. 6. Lynx status caused shifts between ecosystem structures. In the 'interference ecosystem', lynx and hare biomass increased with productivity whilst fox biomass did not. In the 'mesopredator release ecosystem', fox biomass increased with productivity but hare biomass did not. Thus, biomass controlled top-down did not respond to changes in productivity. This fulfils a critical prediction of EEH. 7. We conclude that the cascade involving top predators, mesopredators and their prey can determine large-scale biomass distribution patterns and regional ecosystem structures. Hence, interference within trophic levels has to be taken into account to understand how terrestrial ecosystem structures are shaped.

Parametric imaging: a promising approach for the evaluation of dynamic PET-18F-FDG studies - the DKFZ experience.

Dynamic positron emission studies (dPET) with fluorine-18-fluoro-deoxyglucose ((18)F-FDG) were performed in oncologic patients. The primary aim was to evaluate the impact of parametric imaging and assess its feasibility with regard to diagnostics and treatment management. Parametric PET images based on different algorithms have been calculated. Regression-based images, influx images according to Patlak, two-tissue compartment images as well as non-compartmental approaches, based on the fractal dimension, principal component images, and similarity mapping have been used. Our results showed that the use of parametric images is helpful to visualize quantitative parameters of the tracer kinetics and adds a new dimension to the existing conventional PET or PET/computerized tomography (CT) images. Especially, non-compartment models are computationally fast and can be applied in daily routine to gain more detailed information about the distribution of a tracer over time and space. In conclusion, it is our opinion that parametric images will gain increasing importance and find their way into clinical routine due to the improvement of the technical equipment, like computer power, faster data acquisition by new generations of PET/CT scanners and more sophisticated software for data evaluation.

The use of fluorine-18 fluorodesoxyglycose-positron emission tomography for treatment monitoring in patients with soft tissue sarcomas.

Positron emission tomography (PET) using 2-deoxy-2-[(18)F] fluoro-D-glucose ((18)F-FDG) has been used with increased frequency in the care of patients with soft tissue sarcomas to predict malignant potential of tumours, prognosis of survival and response to chemotherapy. Although there are several other PET tracers, which have found limited use in sarcomas, this review focuses on the use of (18)F-FDG, which is the most common used tracer. Recent literature and developments covering major aspects of PET imaging in the management of patients with soft tissue sarcomas will be discussed in this review with focus on treatment monitoring. Positron emission tomography cannot be used instead of histology to diagnose sarcomas, but may aid in biopsy planning. In particular, using the last generation PET/computerized tomography (CT) scanners, it is easily possible to combine morphological information provided by CT and/or magnetic resonance imaging with biological information based on PET. Imaging with PET has been shown to detect accurately primary tumours as well as lymph node and bone metastases in patients with sarcomas. In soft tissue sarcomas, changes in tumour (18)F-FDG uptake correlate significantly with histopathological response, risk of tumour recurrence and survival. In conclusion, PET is emerging as an important imaging modality in the management of patients with soft tissue sarcomas.