Spanish validation of the Brief Assessment in Cognition in Schizophrenia (BACS) in patients with schizophrenia and healthy controls

Neurocognitive impairment is a core feature of schizophrenia and is closely associated with functional outcome. The importance of cognitive assessment is broadly accepted today, and an easy-to-use, internationality validated cognitive assessment tool is needed by researchers and in daily clinical practice. The Brief Assessment of Cognition in Schizophrenia (BACS) has been validated in English, French, Japanese and Italian. It is as sensitive to cognitive dysfunction as a standard test battery, with the advantage of requiring less than 35minutes to complete. In our study, we tested the psychometric characteristics of a Spanish version of the BACS in 117 patients with schizophrenia-spectrum disorders and 36 healthy controls. All BACS cognitive subtests discriminated between patients and controls (P<.001), and the concurrent validity between the BACS and a traditional neuropsychological test battery was similar to that reported in other languages. We conclude that the BACS can facilitate the comparison of the cognitive performance of patients with schizophrenia in many different countries.

Documenting the location of systematic transrectal ultrasound-guided prostate biopsies: correlation with multi-parametric MRI

During transrectal ultrasound (TRUS)-guided prostate biopsies, the actual location of the biopsy site is rarely documented. Here, we demonstrate the capability of TRUS-magnetic resonance imaging (MRI) image fusion to document the biopsy site and correlate biopsy results with multi-parametric MRI findings. Fifty consecutive patients (median age 61 years) with a median prostate-specific antigen (PSA) level of 5.8 ng/ml underwent 12-core TRUS-guided biopsy of the prostate. Pre-procedural T2-weighted magnetic resonance images were fused to TRUS. A disposable needle guide with miniature tracking sensors was attached to the TRUS probe to enable fusion with MRI. Real-time TRUS images during biopsy and the corresponding tracking information were recorded. Each biopsy site was superimposed onto the MRI. Each biopsy site was classified as positive or negative for cancer based on the results of each MRI sequence. Sensitivity, specificity, and receiver operating curve (ROC) area under the curve (AUC) values were calculated for multi-parametric MRI. Gleason scores for each multi-parametric MRI pattern were also evaluated. Six hundred and 5 systemic biopsy cores were analyzed in 50 patients, of whom 20 patients had 56 positive cores. MRI identified 34 of 56 positive cores. Overall, sensitivity, specificity, and ROC area values for multi-parametric MRI were 0.607, 0.727, 0.667, respectively. TRUS-MRI fusion after biopsy can be used to document the location of each biopsy site, which can then be correlated with MRI findings. Based on correlation with tracked biopsies, T2-weighted MRI and apparent diffusion coefficient maps derived from diffusion-weighted MRI are the most sensitive sequences, whereas the addition of delayed contrast enhancement MRI and three-dimensional magnetic resonance spectroscopy demonstrated higher specificity consistent with results obtained using radical prostatectomy specimens.

Accelerated T2 mapping for characterization of prostate cancer

Prostate T(2) mapping was performed in 34 consecutive patients using an accelerated multiecho spin-echo sequence with 4-fold k-space undersampling leading to a net acceleration factor of 3.3 on a 3T scanner. The mean T(2) values from the accelerated and conventional, unaccelerated sequences demonstrated a very high correlation (r = 0.99). Different prostate segments demonstrated similarly good interscan reproducibility (p = not significant) with slightly larger difference at base: 2.0% ± 1.6% for left base and 2.1% ± 1.1% for right base. In patients with subsequent targeted biopsy, T(2) values of histologically proven malignant tumor areas were significantly lower than the suspicious looking but nonmalignant lesions (p < 0.05) and normal areas (p < 0.001): 100 ± 10 ms for malignant tumors, 114 ± 23 ms for suspicious lesions and 149 ± 32 ms for normal tissues. The proposed method can provide an effective approach for accelerated T(2) quantification for prostate patients.

Magnetic resonance lymphangiography with a nano-sized gadolinium-labeled dendrimer in small and large animal models

AIM

Imaging of the lymphatic system is critical in preoperative planning of resections of complex lymphatic malformations. However, safe, effective imaging methods with sufficient resolution to identify the lymphatics have been lacking. In this study, we demonstrate the use of gadolinium-labeled dendrimers to image the lymphatics in small and large animal models during magnetic resonance lymphangiography.

METHODS

Polyamidoamine G6-Gd_1B4M_N-hydroxysuccinimide was synthesized and administered intradermally in the extremities of normal mice and pigs at several doses.

RESULTS

The lymphatics were well demonstrated in both animal models and there was rapid uptake in the deep lymphatic system, including the thoracic duct. A significant dose reduction was achieved (1 µmol Gd/kg) in the 35-kg pig compared with mice, while still producing excellent results. No toxicity was observed and only minor inflammatory changes were observed at the injection site 30 days later.

CONCLUSION

We demonstrate that a low dose of a macromolecular magnetic resonance contrast agent can provide rapid imaging of the deep lymphatic system in both small and large animals. This data provides a basis to consider a similar agent in clinical trials.

Functionalizing C60 via Nucleophilic Trapping of its Radical Cations: 1. Alkoxylation and Arylation of C60; 2. Synthesis of Earmuff Ethers (Difulleroxyalkanes)

While its electrochemical oxidation is difficult, Cgg is readily oxidized in protic superacidic media. In order to exploit the reactive nature of the radical cations thus formed for the purpose of generating novel fullerene derivatives, a method involving nucleophilic trapping of oxidized Cgg has been developed. Thus, trapping oxidized Cgg with alcohols and aromatics results in the formation of alkoxylated and arylated C60, respectively, while trapping oxidized CgQ with x, y-diols results in the formation of x, y-difulleroxyalkanes (earmuff ethers).

Pharmacologic modulation of serine/threonine phosphorylation highly sensitizes PHEO in a MPC cell and mouse model to conventional chemotherapy

Background

The failure of cytotoxic cancer regimens to cure the most drug-resistant, well-differentiated solid tumors has been attributed to the heterogeneity of cell types that differ in their capacities for growth, differentiation, and metastases. We investigated the effect of LB1, a small molecule inhibitor of serine/threonine protein phosphatase 2A (PP2A), on its ability to inhibit a low growth fraction and highly drug-resistant solid neuroendocrine tumor, such as metastatic pheochromocytoma (PHEO). Subsequently, we evaluated the increased efficacy of chemotherapy combined with LB1.

Methodology/Principal Findings

The effect of LB1 and temozolomide (TMZ), a standard chemotherapeutic agent that alone only transiently suppressed the growth and regression of metastatic PHEO, was evaluated in vitro on a single PHEO cell line and in vivo on mouse model of metastatic PHEO. In the present study, we show that metastatic PHEO, for which there is currently no cure, can be eliminated by combining LB1, thereby inhibiting PP2A, with TMZ. This new treatment approach resulted in long term, disease-free survival of up to 40% of animals bearing multiple intrahepatic metastases, a disease state that the majority of patients die from. Inhibition of PP2A was associated with prevention of G1/S phase arrest by p53 and of mitotic arrest mediated by polo-like kinase 1 (Plk-1).

Conclusions/Significance

The elimination of DNA damage-induced defense mechanisms, through transient pharmacologic inhibition of PP2A, is proposed as a new approach for enhancing the efficacy of non-specific cancer chemotherapy regimens against a broad spectrum of low growth fraction tumors very commonly resistant to cytotoxic drugs.

Magnetic resonance imaging of organic contrast agents in mice: capturing the whole-body redox landscape

Nitroxides are a class of stable free radicals that have several biomedical applications including radioprotection and noninvasive assessment of tissue redox status. For both of these applications, it is necessary to understand the in vivo biodistribution and reduction of nitroxides. In this study, magnetic resonance imaging was used to compare tissue accumulation (concentration) and reduction of two commonly studied nitroxides: the piperidine nitroxide Tempol and the pyrrolidine nitroxide 3-CP. It was found that 3-CP was reduced 3 to 11 times slower (depending on the tissue) than Tempol in vivo and that maximum tissue concentration varies substantially between tissues (0.6-7.2mM). For a given tissue, the maximum concentration usually did not vary between the two nitroxides. Furthermore, using electron paramagnetic resonance spectroscopy, we showed that the nitroxide reduction rate depends only weakly on cellular pO(2) in the oxygen range expected in vivo. These observations, taken with the marked variation in nitroxide reduction rates observed between tissues, suggest that tissue pO(2) is not a major determinant of the nitroxide reduction rate in vivo. For the purpose of redox imaging, 3-CP was shown to be an optimal choice based on the achievable concentrations and bioreduction observed in vivo.

Documenting the location of prostate biopsies with image fusion

OBJECTIVE To develop a system that documents the location of transrectal ultrasonography (TRUS)-guided prostate biopsies by fusing them to MRI scans obtained prior to biopsy, as the actual location of prostate biopsies is rarely known. PATIENTS AND METHODS Fifty patients (median age 61) with a median prostate-specific antigen (PSA) of 5.8 ng/ml underwent 3T endorectal coil MRI prior to biopsy. 3D TRUS images were obtained just prior to standard TRUS-guided 12-core sextant biopsies wherein an electromagnetic positioning device was attached to the needle guide and TRUS probe in order to track the position of each needle pass. The 3D-TRUS image documenting the location of each biopsy was fused electronically to the T2-weighted MRI. Each biopsy needle track was marked on the TRUS images and these were then transposed onto the MRI. Each biopsy site was classified pathologically as positive or negative for cancer and the Gleason score was determined. RESULTS The location of all (n= 605) needle biopsy tracks was successfully documented on the T2-weighted (T2W) MRI. Among 50 patients, 20 had 56 positive cores. At the sites of biopsy, T2W signal was considered 'positive' for cancer (i.e. low in signal intensity) in 34 of 56 sites. CONCLUSION It is feasible to document the location of TRUS-guided prostate biopsies on pre-procedure MRI by fusing the pre-procedure TRUS to an endorectal coil MRI using electromagnetic needle tracking. This procedure may be useful in documenting the location of prior biopsies, improving quality control and thereby avoiding under-sampling of the prostate as well as directing subsequent biopsies to regions of the prostate not previously sampled.

Is apparent diffusion coefficient associated with clinical risk scores for prostate cancers that are visible on 3-T MR images?

PURPOSE

To investigate whether apparent diffusion coefficients (ADCs) derived from diffusion-weighted (DW) magnetic resonance (MR) imaging at 3 T correlate with the clinical risk of prostate cancer in patients with tumors that are visible on MR images, with MR imaging/transrectal ultrasonography (US) fusion-guided biopsy as a reference.

MATERIALS AND METHODS

Forty-eight consecutive patients (median age, 60 years; median serum prostate-specific antigen value, 6.3 ng/mL) who underwent DW imaging during 3-T MR imaging with an endorectal coil were included in this retrospective institutional review board-approved study, and informed consent was obtained from each patient. Patients underwent targeted MR imaging/transrectal US fusion-guided prostate biopsy. Mean ADCs of cancerous target tumors were correlated with Gleason and D'Amico clinical risk scores. The true risk group rate and predictive value of the mean ADC for classifying a tumor by its D'Amico clinical risk score was determined by using linear discriminant and receiver operating characteristic analyses.

RESULTS

A significant negative correlation was found between mean ADCs of tumors in the peripheral zone and their Gleason scores (P = .003; Spearman ρ = -0.60) and D'Amico clinical risk scores (P < .0001; Spearman ρ = -0.69). ADC was found to distinguish tumors in the peripheral zone with intermediate to high clinical risk from those with low clinical risk with a correct classification rate of 0.73.

CONCLUSION

There is a significant negative correlation between ADCs and Gleason and D'Amico clinical risk scores. ADCs may therefore be useful in predicting the aggressiveness of prostate cancer.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100667/-/DC1.

Intuitive pharmacogenetics: spontaneous risperidone dosage is related to CYP2D6, CYP3A5 and ABCB1 genotypes

The aim of this study is to evaluate whether the quantitative prescription of risperidone (dosage) is related to the patient's metabolic status. Metabolic status was defined in terms of the most relevant polymorphisms of CYP2D6 (*3, *4, *5, *6 and *1xN), CYP3A5 (*3A) and ABCB1 (G2677T) determined a posteriori and blinded to the clinicians. This prospective and observational study includes a cohort of 151 Caucasian psychiatric patients treated with risperidone. Significant differences (Kruskal-Wallis test p=0.01) among the doses administered were observed to correlate (Spearman's r=1, p=0.02) with the different CYP2D6 groups. Poor metabolizers received the lowest doses and ultra rapid metabolizers the highest. No significant correlations were observed with regard to CYP3A5 and ABCB1. We find that, despite not knowing patients' metabolic status, clinicians modify risperidone dosage in order to obtain the best therapeutic option.

The role of dynamic contrast-enhanced MRI in cancer diagnosis and treatment

Angiogenesis is a key step in the pathophysiology of tumor growth and metastatic spread. Recently, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has emerged as a method for assessing angiogenesis both during the initial diagnosis and for follow up of anti-angiogenic therapies. In this review, we discuss the technical aspects of implementing DCE-MRI in clinical practice with emphasis on acquisition methods and analytic techniques.

Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates

In this report we directly compare the in vivo and in vitro MRI properties of gadolinium-dendrimer conjugates of derivatized acyclic diethylenetriamine-N,N',N',N'',N''-pentaacetic acid (1B4M-DTPA) and macrocyclic 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (C-DOTA). The metal-ligand chelates were pre-formed in alcohol prior to conjugation to the generation 4 PAMAM dendrimer (G4D), and the dendrimer-based agents were purified by Sephadex(R) G-25 column. The analysis and SE-HPLC data indicated chelate to dendrimer ratios of 30:1 and 28:1, respectively. Molar relaxivity measured at pH 7.4, 22 degrees C, and 3T are comparable (29.5 vs 26.9 mM(-1)s(-1)), and both conjugates are equally viable as MRI contrast agents based on the images obtained. The macrocyclic agent however exhibits a faster rate of clearance in vivo (t(1/2)=16 vs 29 min). Our conclusion is that the macrocyclic-based agent is the more suitable agent for in vivo use for these reasons combined with kinetic inertness associated with the Gd(III) DOTA complex stability properties.

Prostate cancer: value of multiparametric MR imaging at 3 T for detection--histopathologic correlation

PURPOSE

To determine utility of multiparametric imaging performed at 3 T for detection of prostate cancer by using T2-weighted magnetic resonance (MR) imaging, MR spectroscopy, and dynamic contrast material-enhanced MR imaging, with whole-mount pathologic findings as reference standard.

MATERIALS AND METHODS

This prospectively designed, HIPAA-compliant, single-institution study was approved by the local institutional review board. Seventy consecutive patients (mean age, 60.4 years; mean prostate-specific antigen level, 5.47 ng/mL [5.47 microg/L]; range, 1-19.9 ng/mL [1-19.9 microg/L]) were included; informed consent was obtained from each patient. All patients had biopsy-proved prostate cancer, with a median Gleason score of 7 (range, 6-9). Images were obtained by using a combination of six-channel cardiac and endorectal coils. MR imaging and pathologic findings were evaluated independently and blinded and then correlated with histopathologic findings by using side-by-side comparison. Analyses were conducted with a raw stringent approach and an alternative neighboring method, which accounted for surgical deformation, shrinkage, and nonuniform slicing factors in pathologic specimens. Generalized estimating equations (GEEs) were used to estimate the predictive value of region-specific, pathologically determined cancer for all three modalities. This approach accounts for the correlation among multiple regions in the same individual.

RESULTS

For T2-weighted MR imaging, sensitivity and specificity values obtained with stringent approach were 0.42 (95% confidence interval [CI]: 0.36, 0.47) and 0.83 (95% CI: 0.81, 0.86), and for the alternative neighboring approach, sensitivity and specificity values were 0.73 (95% CI: 0.67, 0.78) and 0.89 (95% CI: 0.85, 0.93), respectively. The combined diagnostic accuracy of T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy for peripheral zone tumors was examined by calculating their predictive value with different combinations of techniques; T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy provided significant independent and additive predictive value when GEEs were used (P < .001, P = .02, P = .002, respectively).

CONCLUSION

Multiparametric MR imaging (T2-weighted MR imaging, MR spectroscopy, dynamic contrast-enhanced MR imaging) of the prostate at 3 T enables tumor detection, with reasonable sensitivity and specificity values.

Determination of alkylphenols in eluates from pyrolysis solid residues using dispersive liquid-liquid microextraction

Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) was applied for the determination of 11 alkylphenols in eluates of chars produced in the co-pyrolysis of different wastes. The optimized DLLME procedure, 4 mL of sample solution, 15 microL of trichloroethylene as extraction solvent, 1 mL of acetone as dispersion solvent and addition of 15% (w/v) of NaCl, was validated. Under the optimum conditions, the enrichment factors were in the range of 82-180. Calibration curves were constructed for each analyte in pure water in the concentration range of 0.5-8 microg/L with correlation coefficients higher than 0.999. The limits of detection were between 0.07 and 0.17 microg/L. The repeatability of the method was evaluated using water samples fortified with the analyte mixture at two concentration levels: the relative standard deviation (RSD) values were between 3.7% and 8.0% for a concentration of 0.5 microg/L, and between 4.2% and 6.4% for a concentration of 3 microg/L. The recoveries of the analytes evaluated by fortification of real eluate samples were in the range of 67.9-97.9% for eluate 1 (obtained from a decontaminated char) and in the range of 61.9-101.4% for eluate 2 (obtained from the untreated char). o-Methylphenol presented low recoveries for both eluates showing a possible matrix effect. The results obtained show that this method is adequate for the determination of alkylphenols in environmental aqueous samples and presents itself as a fast and inexpensive technique, using minor amounts of organic solvents.

Preparation and characterization of a magnetic and optical dual-modality molecular probe

Multi-modality imaging probes combine the advantages of individual imaging techniques to yield highly detailed anatomic and molecular information in living organisms. Herein, we report the synthesis and characterization of a dual-modality nanoprobe that couples the magnetic properties of ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) with the near infrared fluorescence of Cy5.5. The fluorophore is encapsulated in a biocompatible shell of silica surrounding the iron oxide core for a final diameter of approximately 17 nm. This silica-coated iron oxide nanoparticle (SCION) has been analyzed by transmission electron microscopy, dynamic light scattering, and superconducting quantum interference device (SQUID). The particle demonstrates a strong negative surface charge and maintains colloidal stability in the physiological pH range. Magnetic hysteresis analysis confirms superparamagnetic properties that could be manipulated for thermotherapy. The viability of primary human monocytes, T cells, and B cells incubated with the particle has been examined in vitro. In vivo analysis of agent leakage into subcutaneous A431 tumors in mice was also conducted. This particle has been designed for diagnostic application with magnetic resonance and fluorescence imaging, and has future potential to serve as a heat-sensitive targeted drug delivery platform.

A method for correlating in vivo prostate magnetic resonance imaging and histopathology using individualized magnetic resonance-based molds

A method for the design and rapid manufacture of a patient specific tissue slicing device based on in vivo images in order to facilitate the process of correlating the images with histopathology is presented. The method is applied to radical prostatectomy specimens where the customized mold is designed using magnetic resonance (MR) images of each patient obtained prior to surgery. In this case, the mold holds the prostate in place while a knife with a single blade or multiple blades is inserted in slots which are positioned to obtain tissue blocks corresponding to the slices in the MR images. The resulting histological specimens demonstrate good anatomical correlation with the MR images.

A new approach in the preparation of dendrimer-based bifunctional diethylenetriaminepentaacetic acid MR contrast agent derivatives

In this paper, we report a new method to prepare and characterize a contrast agent based on a fourth-generation (G4) polyamidoamine (PAMAM) dendrimer conjugated to the gadolinium complex of the bifunctional diethylenetriamine pentaacetic acid derivative (1B4M-DTPA). The method involves preforming the metal-ligand chelate in alcohol prior to conjugation to the dendrimer. The dendrimer-based agent was purified by a Sephadex G-25 column and characterized by elemental analysis. The analysis and SE-HPLC data gave a chelate to dendrimer ratio of 30:1 suggesting conjugation at approximately every other amine terminal on the dendrimer. Molar relaxivity of the agent measured at pH 7.4 displayed a higher value than that of the analogous G4 dendrimer based agent prepared by the postmetal incorporation method (r(1) = 26.9 vs 13.9 mM(-1) s(-1) at 3 T and 22 degrees C). This is hypothesized to be due to the higher hydrophobicity of this conjugate and the lack of available charged carboxylate groups from noncomplexed free ligands that might coordinate to the metal and thus also reduce water exchange sites. Additionally, the distribution populations of compounds that result from the postmetal incorporation route are eliminated from the current product simplifying characterization as quality control issues pertaining to the production of such agents for clinical use as MR contrast agents. In vivo imaging in mice showed a reasonably fast clearance (t(1/2) = 24 min) suggesting a viable agent for use in clinical application.

Imaging of tumor angiogenesis: functional or targeted?

OBJECTIVE

Angiogenesis--the growth of new vessels--is both a normal physiologic response and a critical step in many pathologic processes, particularly cancer. Imaging has long relied on the different enhancement characteristics of cancer compared with normal tissue; the information generated is often primarily morphologic and qualitative. However, more quantitative methods based on functional and targeted imaging have recently emerged.

CONCLUSION

In this article, we review both functional and targeted imaging techniques for assessing tumor angiogenesis.

Noninvasive monitoring of a murine model of metastatic pheochromocytoma: a comparison of contrast-enhanced microCT and nonenhanced MRI

PURPOSE

To compare contrast-enhanced micro-computed tomography (microCT) and nonenhanced respiratory-triggered magnetic resonance imaging (MRI) in an animal model of metastatic pheochromocytoma. Animal models are becoming important in the study of cancer treatment and imaging is useful in minimizing the number of animals needed and reducing costs associated with autopsies. However, the choice of imaging modality is still evolving.

MATERIALS AND METHODS

Adult female nude mice were injected by tail vein with a mouse pheochromocytoma (MPC) cell line (MPC 4/30PRR) to create a metastatic model. After optimizing imaging techniques, eight mice were imaged with both respiratory triggered MRI and microCT and the findings were verified histologically.

RESULTS

MicroCT and MRI were approximately equal in their ability to detect hepatic metastases at a size threshold of 350 microm. In the lungs, MRI was more sensitive than microCT, detecting lesions 0.6 mm in diameter versus 1 mm for microCT. Additionally, MRI was more sensitive for lesions in the kidneys, bone, ovaries, and adrenal glands. MRI demonstrated a higher contrast-to-noise ratio (CNR) than microCT.

CONCLUSION

In addition to the advantage of not exposing the animal to ionizing radiation, MRI provided a more complete assessment of the extent of metastases in this model compared to microCT.

Prevalence of Metabolic Syndrome in Spanish Patients with Schizophrenia and Overweight

Aims:

The metabolic syndrome MS (visceral obesity, dyslipidaemia, hyperglycaemia, and hypertension), has become one of the major public-health challenges worldwide. Patients with schizophrenia are more likely to suffer from MS that the general population. We have analyzed the prevalence of MS in Spanish patients with schizophrenia and overweight.

Methods:

The CRESSOB study is a 12-month, prospective, naturalistic study including 110 community mental health clinics selected at random. Each site enrolled four consecutive patients with diagnosis of schizophrenia, according to DSM-IV TR criteria, and overweight (BMI > 25 Kg/m2). to assess the prevalence of MS we have analyzed the baseline results of the CRESSOB study. the National Cholesterol Educational Program (NCEP-ATPIII), the International Diabetes Federation (IDF) and the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) definitions were used to established the presence of MS.

Results:

A total of 391 patients were enrolled on the study (mean age 40.5 years, 63.8% men). 75.9% of the patients did not meet criteria for remission, using the selected PANSS items. Mean GAF score was 52.7 (SD 15.4). Using the different criteria, 59.0% of males and 58.3% of females fulfilled the NCEP-ATPIII criteria, 71.1% of males and 65.8% of females fulfilled the IDF criteria and 70.1% of males and 65.1% of females fulfilled the AHA/NHLBI criteria.

Conclusions:

The MS is highly prevalent in Spanish patients with schizophrenia and overweight. Given the metabolic syndrome is an important risk factor for cardiovascular disease, these patients should receive appropriate clinical monitoring for this syndrome.

Abstract B59: Magnetic resonance imaging monitoring of tumor promotion and tumor progression in mouse model of inflammation-promoted colon cancer

B59

Purpose

Early detection of pre-cancerous tissue has significantly increased survival for most cancers including colorectal cancer. Animal models that follow early stages of cancer are valuable for identifying molecular events and response indicators that correlate with the early stages of tumor development. The goal of this work was to generate new methods to monitor over time the early stages of colorectal cancer in mice using magnetic resonance imaging (MRI).

Experimental Design

Mice treated with azoxymethane and dextran sulafate sodium (DSS) were imaged by MRI throughout the tumor development. Early inflammation was imaged in T2-weighted MRI. Dark-lumen images were obtained in both T1 and T2-weighted images using a poly-fluorinated liquid enema. Individual tumor volumes were calculated and validated ex vivo.

Results

Using T2-weighted MRI, inflammation was detected 3 days after DSS exposure and subsided over the next week. The poly-fluorinated liquid enema distended the colon and provided a clear differentiation of the lumen of the colon from the mucosal lining. Tumors were detected as early as 29 days after initiation and as small as 1.2 mm3. Individual tumor growths were followed over time and tumor volumes measured by MRI correlated with volumes measured ex vivo.

Conclusions

Early detection of tumorigenesis is important for understanding tumor development. The use of MRI for detection of the initial stages of colon cancer allows real time evaluation of preclinical trials for prevention and intervention. The use of the poly-fluorinated liquid enema for Dark-lumen MRI in both T1 and T2-weighted imaging could simplify clinical MRI detection of colon cancer.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):B59.

A dual CT-MR dendrimer contrast agent as a surrogate marker for convection-enhanced delivery of intracerebral macromolecular therapeutic agents

The feasibility of using Gd dendrimer-based macromolecules (Gd-G8 dendrimer) as a dual CT and MR contrast agent for monitoring convection-enhanced delivery of therapy in the brain is evaluated both in vitro and in vivo with optimal dosing established. In vitro CT attenuation values of the Gd-based agents ( approximately 6.0 HU mM(-1)) were approximately 1.6 times greater than iodine-based agents and the attenuation of the Gd-DTPA was comparable to Gd-G8 dendrimer. Visible enhancement was observed on both CT and MR using Gd-G8 dendrimer over a range of 23-78 mM; however, a concentration of at least 47 mM in Gd was required for adequate delineation of the injection site on both CT and MR. MR offers greater sensitivity than CT in estimating the volume of distribution (V(d)) and effectively quantified the agent's concentration and diffusion using T(1) mapping at much lower concentrations of Gd (<10 mM in [Gd]).

Synthesis, characterization, and biological evaluation of integrin alphavbeta3-targeted PAMAM dendrimers

Ligand size and valency strongly influence the receptor uptake and clearance of tumor angiogenesis imaging agents. The structures of successful imaging agents exhibit a high degree of variability, encompassing small monovalent arginine-glycine-aspartic acid (RGD)-containing peptides, multivalent RGD-oligomers, and a monoclonal antibody against integrin alpha-v-beta-3 (alpha-v-beta-3). We have pursued a nanoscale approach to imaging of angiogenesis using rationally designed polyamidoamine (PAMAM) dendrimers covalently adorned with RGD-cyclopeptides. An orthogonal oxime-ligation strategy was applied to chemoselectively effect conjugation of the PAMAM dendrimers with RGD-cyclopeptides for targeting alpha vbeta 3. Fluorescent dyes for optical imaging and chelates for gadolinium-based magnetic resonance (MR) imaging were subsequently appended to create robust multimodal macromolecular imaging agents. Fluorescence microscopy revealed selective binding of the resulting RGD peptide-bearing dendrimer with empty chelates to alpha-v-beta-3-expressing cells, but somewhat reduced selectivity was observed following Gd(III) complexation. The expected incomplete saturation of chelates with Gd(III) ions permitted radiometal complexation, and an in vivo tissue distribution of the resulting agent in M21 melanoma tumor-bearing mice showed mostly renal and reticuloendothelial accumulation, with the tumor:blood ratio peaking (3.30+/-0.03) at 2 h postinjection.

Dental Amalgam and Antibiotic- and/or Mercury-resistant Bacteria

Mercury emitted from dental amalgam may select for increased numbers of antibiotic- or mercury-resistant commensal bacteria in patients and increase their risk for bacterial diseases that are resistant to common therapies. We hypothesized that the presence of dental amalgams would increase the level of mercury-, tetracycline-, ampicillin-, erythromycin-, or chloramphenicol-resistant oral and urinary bacteria as compared with levels in children receiving composite fillings. Samples were collected at baseline, 3–6 months after the initial dental treatment, and annually for 7 years of follow-up. There were no statistically significant differences between treatment groups in the numbers of bacteria growing on antibiotic- or mercury-supplemented plates. This study provided no evidence that amalgam fillings on posterior teeth influenced the level of antibiotic- or mercury-resistant oral or urinary bacteria as detected by culture.