Unconventional non-amino acidic PET radiotracers for molecular imaging in gliomas

PURPOSE

The objective of this review was to explore the potential clinical application of unconventional non-amino acid PET radiopharmaceuticals in patients with gliomas.

METHODS

A comprehensive search strategy was used based on SCOPUS and PubMed databases using the following string: ("perfusion" OR "angiogenesis" OR "hypoxia" OR "neuroinflammation" OR proliferation OR invasiveness) AND ("brain tumor" OR "glioma") AND ("Positron Emission Tomography" OR PET). From all studies published in English, the most relevant articles were selected for this review, evaluating the mostly used PET radiopharmaceuticals in research centers, beyond amino acid radiotracers and 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG), for the assessment of different biological features, such as perfusion, angiogenesis, hypoxia, neuroinflammation, cell proliferation, tumor invasiveness, and other biological characteristics in patients with glioma.

RESULTS

At present, the use of non-amino acid PET radiopharmaceuticals specifically designed to assess perfusion, angiogenesis, hypoxia, neuroinflammation, cell proliferation, tumor invasiveness, and other biological features in glioma is still limited.

CONCLUSION

The use of investigational PET radiopharmaceuticals should be further explored considering their promising potential and studies specifically designed to validate these preliminary findings are needed. In the clinical scenario, advancements in the development of new PET radiopharmaceuticals and new imaging technologies (e.g., PET/MR and the application of the artificial intelligence to medical images) might contribute to improve the clinical translation of these novel radiotracers in the assessment of gliomas.

Reclassification of cardiovascular risk by myocardial perfusion imaging in diabetic patients with abnormal resting electrocardiogram

BACKGROUND AND AIMS

Despite an extensive use of stress myocardial perfusion single-photon emission computed tomography (MPS), no study addressed the role of perfusion imaging in diabetic patients with abnormal resting electrocardiogram (ECG). We compared analytical approaches to assess the added value of stress MPS variables in estimating coronary heart disease outcomes in diabetic patients with abnormal resting ECG.

METHODS AND RESULTS

A total of 416 patients with diabetes and abnormal resting ECG who underwent stress MPS were prospectively followed up after the index study. The end point was the occurrence of a major cardiac event, including cardiac death and nonfatal myocardial infarction. At the end of follow-up (median 58 months), 42 patients experienced events. MPS data increased the predictive value of a model including traditional cardiovascular risk factors and left ventricular (LV) ejection fraction (likelihood ratio χ² from 17.54 to 24.15, p < 0.05, with a C statistic of 0.72, 95% confidence interval: 0.65-0.79). The addition of MPS data resulted in reclassification of 25% of the sample with a net reclassification improvement of 0.20 (95% confidence interval: 0.05-0.36). Overall, 63 patients were reclassified to a lower risk category, with a 5-year event rate of 3.5%, and 40 patients were reclassified to a higher risk category, with a 5-year event rate of 20%.

CONCLUSION

The addition of MPS findings to a model based on traditional cardiovascular risk factors and LV ejection fraction improves risk classification for incident cardiac events in diabetic patients with abnormal resting ECG.

Microdosimetric measurements in the thermal neutron irradiation facility of LENA reactor

A twin TEPC with electric-field guard tubes has been constructed to be used to characterize the BNCT field of the irradiation facility of LENA reactor. One of the two mini TEPC was doped with 50ppm of (10)B in order to simulate the BNC events occurring in BNCT. By properly processing the two microdosimetric spectra, the gamma, neutron and BNC spectral components can be derived with good precision (~6%). However, direct measurements of (10)B in some doped plastic samples, which were used for constructing the cathode walls, point out the scarce accuracy of the nominal (10)B concentration value. The influence of the Boral(®) door, which closes the irradiation channel, has been measured. The gamma dose increases significantly (+51%) when the Boral(®) door is closed. The crypt-cell-regeneration weighting function has been used to measure the quality, namely the RBEµ value, of the radiation field in different conditions. The measured RBEµ values are only partially consistent with the RBE values of other BNCT facilities.

Current and future perspectives in diagnostic imaging as a guide to targeted/local therapies in breast cancer recurrence

In recent years, a multidisciplinary approach for breast cancer patient management has been adopted to provide an accurate evaluation of primary/recurrent tumor and to guiding appropriate treatment. The introduction of positron emission tomography (PET) and PET/computed tomography (CT) with 18F-fluorodeoxyglucose and other radiolabelled molecules for the early detection of breast cancer recurrence has important consequences both for staging and treatment planning. In particular, in the last few years, research efforts have been made to guide targeted or local therapies directing against the cancer outgrowth. Based on the available data in the literature, in the present review, we will discuss 1) the role of PET and PET/CT in guiding local therapies for breast cancer recurrences, (both loco-regional and distant sites); and 2) its current status in clinical practice and its possible future role.

Comparison of 18F-FDG positron emission tomography/computed tomography and computed tomography in patients with already-treated breast cancer: diagnostic and prognostic implications

AIM

The purpose of the study was to assess the comparison of 18F-FDG PET/CT and CT in patients with breast cancer (BC) already treated with primary therapy, in evaluating the diagnostic and prognostic values.

METHODS

We retrospectively studied 190 patients (187 women and 3 men, mean age 61±11 years) with previous BC (all stages) after surgery and other primary treatments. They underwent within three months CT and 18F-FDG PET/CT examinations for the evaluation of disease status. Disease relapse was confirmed by clinical evaluation and/or radiological findings. Survival curves of disease-free survival (DFS) and overall survival (OS) were computed using Kaplan-Meier method. Cox analysis regression was used to determine predictive factors of DFS and OS.

RESULTS

Of the overall 190 patients, 82 (43%) had evidence of clinical and/or imaging disease relapse, while 108 (57%) did not. Sensitivity, specificity, negative predictive and positive predictive values for disease relapse or progression were of 89% vs. 77%, 73% vs. 53%, 90% vs. 75% and 72% vs. 55%, respectively for PET/CT and CT. DFS curves were significantly different in patients with both negative and positive PET/CT and CT (log-rank test 33.6; P<0.0001 and 12.7; P=0.003, respectively). OS curves were similar in patients with positive/negative PET/CT and CT (P=NS). By both univariate and multivariate Cox regression analysis positive PET/CT was found to be related to the disease recurrence (HR 0.18 and 0.20, both P<0.0001, respectively).

CONCLUSION

PET/CT is more accurate than CT in identification of disease relapse in a large population of BC patients. In women at high-risk of recurrence, PET/CT imaging can provide the early detection of BC metastases, tailoring a proper treatment.

P4-16-06: Expression Patterns of Receptor Activator of Nuclear Factor-kB (RANK) and Src in a Series of Primary Breast Tumors (BT) and Bone Metastases (BM) in Patients (pts) with Metastatic Breast Cancer (MBC)

Background

BM develops in 65–70% of pts with MBC. RANK and its ligand (RANK-L) can be critical in the development and progression of BM. Src overexpression and deregulation occurs in many solid tumors but it has not been fully characterized although an association between Src activity defined by a gene expression signature and BM particularly in ER+ pts has been described. (Zhang XH et al. Cancer Cell. 2009) Our goal was to elucidate the relationship between Src and RANK expression in BT and BM in relation to estrogen-/progesterone-receptor (ER/PR)/HER2 expression and tumor histology (invasive ductal carcinoma (IDC) vs invasive lobular carcinoma (ILC)).

Methods: Immunohistochemistry (IHC) for RANK (R&D Systems clone 80707) and Src (Cell Applications Inc. Phospho Tyr-416) protein expression was performed on archived paraffin embedded BT and BM. Scoring: 0=negative, 1+=weak, 2+=intermediate, 3+=strong and the percent of positive tumor cells; RANK+ = 2–3+, &gt; 1% of cells; Src+ = 1–3+; &gt; 1% of cells. Associations between RANK/Src expression and tumor characteristics were assessed using the chi-square test or McNemar's test for pairs, as appropriate.

Results: From the MSKCC database, using an IRB-approved waiver of consent, we identified 54 pts with MBC who underwent surgical biopsy of a metastatic bone lesion at our center between 2005–2010, and had tissue available for further testing. 17 corresponding BT samples were identified. At the time of diagnosis, 43 (79.5%) primary tumors were ER or PR (+); 6 (11%) were HER2+; 41 (76%) were invasive ductal carcinoma. 87% of BM expressed RANK and 44% expressed Src. (Table 1) No significant correlation between RANK or Src expression in BM and ER/PR/HER2 status of BT was observed. A significant correlation between RANK expression and BT histology was observed, (p=0.0016): 93% of IDC were RANK (+), in comparison to 50% of invasive lobular carcinomas. RANK expression was not significantly different between primary tumor and metastatic bone samples (p=0.99). There was a borderline significant difference in Src expression between primary and metastatic site (p=.06).

Standardized uptake value (SUV) by positron emission tomography/computed tomography (PET/CT) as a prognostic variable in metastatic breast cancer (MBC)

3

Background: The accurate prediction of outcome from MBC could be useful if it could guide more effective therapies. Because PET/CT combines anatomical with functional imaging it could enable greater individualization of treatment. However, there is substantial SUV variation by anatomic site. In this retrospective, single-institution study, we examine baseline SUV on PET/CT as a predictor of outcome from MBC.

Methods: Patients (Pts) with ≥1 metastatic lesion on PET/CT performed ≤60 days of diagnosis of MBC from 01/01/2001-12/31/2008 were identified through institutional databases. Pts who rcvd chemotherapy within 30 days prior to PET/CT were excluded. Electronic medical record reports were reviewed and maximum SUV (SUV-MAX) by site for lesions in bone, liver, lung and lymph node (LN) was recorded. In a secondary analysis, PET/CT scans were reviewed and SUV-MAX recalculated. Relationships between SUV-MAX and OS were assessed using Cox regression by site.

Results: We identified 285 pts, median (med) age 57 yrs (range 27-90) who had PET/CT at med of 2.3 yrs (range 0–41) from primary BC (67% ER+ and 21% HER2+). Med time between PET/CT and MBC diagnosis was -9 days (range -58–59). At med follow-up of 53 mths, 163 pts have died. Med OS is 41 mths (95%CI 34-48). The SUV-MAX by site was; bone (N=159) med 7.0 (range 2.1–29.6); liver (N=55) med 8.2 (range 2.9–51.2); lung (N=89) med 4.7 (range 1.1–24.0); LN (N=180) med 6.9 (range 1.2–34.0). On univariate analysis, higher SUV in bone was associated with shorter survival (p<0.001; table). This was maintained in multivariate analyses after adjusting for known prognostic variables (p=0.02). A similar trend for shorter survival for higher SUV was noted in liver (p=0.07). However, no relationship between SUV and OS was noted in lung (p =0.34) and LN (p=0.6).

Conclusions: This large retrospective study of pts with chemotherapy-naïve MBC suggests that SUV-MAX in bone strongly correlates with prognosis.

[Table: see text]

Cardiovascular risk stratification of diabetic patients

Diabetes mellitus is a complex clinical entity that will grow in importance in the future. The complications of diabetes have a significant impact on patient survival and quality of life, particularly with respect to coronary artery disease (CAD). Appropriate screening and aggressive intervention can significantly benefit many patients with diabetes. In addition, it is important to consider strategies useful not only in the diagnosis of CAD but also in the prognostic evaluation of diabetic patients with coronary disease. Prognostic data are essential in defining risk categories and to apply appropriate treatment for the degree of risk. Therefore, accurate cardiovascular risk stratification of patients with type 2 diabetes is required. However, this can be a problematic issue because the clinical presentation and progression of CAD differs between diabetic and nondiabetic subjects. In addition to a higher prevalence of CAD, patients with diabetes experience more diffuse and extensive coronary artery involvement, more often have left ventricular dysfunction, a more advanced coronary disease at the time of diagnosis, and more often experience silent ischemia. Furthermore, diabetic patients have frequently a less favorable response to revascularization procedures and a poorer long-term outcome. The purpose of this review is to discuss the relative role of various procedures for diagnosis of CAD and for cardiac risk stratification in patients with diabetes.

Cardiac performance during exercise in hypertensive patients without ventricular hypertrophy

BACKGROUND

Reduced systolic reserve on effort may be present in subjects with hypertension but no evidence of hypertensive cardiomyopathy. We assessed the determinants of abnormal cardiac performance during exercise in hypertensive patients without left ventricular hypertrophy.

MATERIALS AND METHODS

Thirty-five newly diagnosed, never-treated-earlier hypertensive patients without definite indication for left ventricular hypertrophy at echocardiography underwent radionuclide ambulatory monitoring of left ventricular function at rest and during upright bicycle exercise testing.

RESULTS

The patients were classified into two groups according to their ejection fraction response to exercise. In 21 patients (group 1), the ejection fraction increased > or = 5% with exercise and in 14 patients (group 2), the ejection fraction either increased < 5% or decreased with exercise. Patients of group 1 had lower peak filling rate at rest and less augmentation in end-diastolic volume during exercise (both P < 0.01) when compared with patients of group 2. A significant relationship between the magnitude of change in ejection fraction with exercise and both peak filling rate at rest (r = 0.58, P < 0.01) and exercise-induced change in end-diastolic volume (r = 0.45, P < 0.01) was found.

CONCLUSIONS

In newly diagnosed, never-treated-earlier hypertensive subjects with no evidence of hypertensive cardiomyopathy, the cardiac response to exercise is dependent on adequate diastolic filling volume to maintain systolic performance.

Factors associated with lack of antiretroviral adherence among adolescents in a reference centre in Rio de Janeiro, Brazil

The objective of this study was to describe the adherence to antiretroviral therapy (ART) among adolescents followed-up in Rio de Janeiro. This cross-sectional study included all adolescents (aged 10-19 years) followed at Instituto de Puericultura e Pediatria Martagão Gesteira and Hospital Universitário Clementino Fraga Filho. Adherence was determined by self-report (number of missed ART doses in three days prior to the interview). Adherence was categorized as taking > or = 95% of the ARTs (adherent), or < 95% (non-adherent). Variables related to demographics and treatment were evaluated and if P value < or = 0.15, they were selected for a logistic regression analysis. One hundred and one adolescents were interviewed. The mean time on ART was 91 months and the mean adherence was 94% of this, 21 were non-adherent, and 80 adherent. The risk factors associated with non-adherence were: if the patient was not concerned about ART, odds ratio (OR) = 3.47 (95% confidence interval [CI] = 1.13-10.68); if they do not carry an extra dose of ART, OR = 6.63 (95% CI = 1.73-25.47); if a health-care worker taught them how to take ART, OR = 0.27 (95% CI = 0.08-0.93). Adherence among adolescents was higher than expected. Factors associated with lack of adherence were: interviewees being unaware of ARTs and lack of commitment to the treatment. Interventions involving these factors must be evaluated.

Homogeneous Cell- and Bead-Based Assays for High Throughput Screening Using Fluorometric Microvolume Assay Technology

High throughput drug screening has become a critical component of the drug discovery process. The screening of libraries containing hundreds of thousands of compounds has resulted in a requirement for assays and instrumentation that are amenable to nonradioactive formats and that can be miniaturized. Homogeneous assays that minimize upstream automation of the individual assays are also preferable. Fluorometric microvolume assay technology (FMAT) is a fluorescence-based platform for the development of nonradioactive cell- and bead-based assays for HTS. This technology is plate format-independent, and while it was designed specifically for homogeneous ligand binding and immunological assays, it is amenable to any assay utilizing a fluorescent cell or bead. The instrument fits on a standard laboratory bench and consists of a laser scanner that generates a 1 mm(2) digitized image of a 100-µmm deep section of the bottom of a microwell plate. The instrument is directly compatible with a Zymark Twistertrade mark (Zymark Corp., Hopkinton, MA) for robotic loading of the scanner and unattended operation in HTS mode. Fluorescent cells or beads at the bottom of the well are detected as localized areas of concentrated fluorescence using data processing. Unbound flurophore comprising the background signal is ignored, allowing for the development of a wide variety of homogeneous assays. The use of FMAT for peptide ligand binding assays, immunofluorescence, apoptosis and cytotoxicity, and bead-based immunocapture assays is described here, along with a general overview of the instrument and software.

Biological activity of Melaleuca alternifola (Tea Tree) oil component, terpinen-4-ol, in human myelocytic cell line HL-60

BACKGROUND

Tea tree oil is an aboriginal Australian traditional medicine for bruises, insect bites, and skin infections. It was rediscovered in the 1920s as a topical antiseptic that is more effective than Phenol. Previous studies have demonstrated its antiseptic qualities, but its effects on human white blood cells have never been investigated.

OBJECTIVE

To test the hypothesis that tea tree oil exerts its antiseptic action through white blood cell activation.

METHODS

Crude oil and the purified "active" component were studied by using a model system that responds to bioactive components by induction of differentiation in white blood cells. Methods used included white blood cell oxidative burst assay (nitroblue tetrazolium [NBT] dye reduction); cell proliferation assay (tritiated thymidine incorporation); cell surface differentiation marker assay (flow cytometric quantitation of phycoerythrin-anti-CD 11b binding); cell viability assay (trypan blue exclusion); and cellular differentiation enzyme assay (white cell esterase staining).

RESULTS

Collectively, five assays that measure differentiation in white blood cells indicated monocytic differentiation after treatment with either crude oil or the purified active component. Both the crude oil and the purified active component, (+:-) terpinene-4-ol, caused a similar type and amount of differentiation. The culture of cells in medium containing serum caused more activation than in medium containing no serum.

CONCLUSION

The antiseptic activity of tea tree oil appears to be due, in part, to white blood cell activation.

A homogeneous and multiplexed immunoassay for high-throughput screening using fluorometric microvolume assay technology

We have developed a simple, homogeneous bead-based immunoassay for use with fluorometric microvolume assay technology (FMAT). The FLISA (fluorescence-linked immunosorbent assay) can be easily adapted from existing immunoassays, is comparable to traditional ELISAs with respect to linear dynamic range and sensitivity, and can be readily performed in 96- and 384-well plates. Additionally, the FLISA utilizes 100-fold less primary antibody than the conventional immunoassay. The scanner uses a helium/neon laser to image and measure bead-bound fluorescence while the background fluorescence is ignored. Consequently, no wash steps are required to remove unbound antibody, ligand, and fluorophore. Furthermore, the instrument is capable of detecting two different fluorescent dyes, allowing for multiplexed assays based on color. Fluorescent bead-based immunoassays were developed for the cytokines IL-6 and IL-8, and their use in both one-color and two-color FLISAs is demonstrated. Although no wash steps were employed, the FLISA was able to accurately measure the concentrations of IL-6 and IL-8 in the growth media of cytokine-stimulated HUVEC cells. In addition, a simulated high-throughput two-color FLISA positively identified those wells in a 384-well plate that contained different amounts of IL-6 and/or IL-8 peptide. The homogeneous, multiplex and multiplate format of the FLISA reduces hands-on time and reagent usage, and is therefore ideally suited for high-throughput screening.

Retention and use of cardiopulmonary resuscitation skills in parents of infants at risk for cardiopulmonary arrest

Policies of most neonatal intensive care units include teaching cardiopulmonary resuscitation (CPR) to parents or other caretakers prior to infant hospital discharge. However, little is known about CPR skills retention in this population or the outcome of parents' use of CPR. This is a study to measure CPR skills 6 months following CPR training to identify characteristics predicting successful performance and to determine if parents used CPR. A sample of 100 parents or related caretakers of infants at risk for an out-of-hospital respiratory or cardiac arrest 6 months following CPR training were asked to demonstrate CPR on an infant mannequin and 94 agreed to participate. Although they were excluded from the study if they had a CPR course within the past 2 years, 37% had taken CPR sometime in the past. Only one third of participants (n = 31, 33%) were able to perform satisfactory CPR. Those who demonstrated satisfactory CPR skills were more likely to have had previous CPR training and to have experienced higher levels of social support at the time of training than those who achieved unsatisfactory CPR performance ratings (p < .05). A logistic regression analysis revealed previous CPR training, social support, and level of anxiety at time of CPR training to be the most important predictors of CPR skills retention. Seven parents reported using CPR to resuscitate their infant who had suffered a respiratory arrest. All seven were successful. CPR skills decay is significant for caregivers of infants at high risk for cardiopulmonary arrest. Parents should be encouraged to review the steps of CPR frequently and to attend refresher classes. A significant proportion of parents of infants hospitalized in the neonatal intensive care unit are called upon to use CPR and are able to use it appropriately.

Effects of carboxy-terminal truncation on human lecithin:cholesterol acyltransferase activity

Mutagenesis was carried out in human lecithin:cholesterol acyltransferase (LCAT) to generate mutants with stop codons at positions corresponding to amino acids 315, 341, 359, 375, 388, 394, and 398 of the 416-amino acid sequence of the mature enzyme protein. Deletion of the 18 terminal amino acids of the protein was without effect on LCAT phospholipase or acyltransferase activity, or the stability of the protein to denaturation at 37 degrees C. Further deletion led to loss of most of the activity, associated with a 10-fold increase in the rate of denaturation at 37 degrees C. These data indicate that the proline-rich C-terminus of LCAT is not required for effective enzyme activity. The loss of activity that accompanied deletion of residues 394-398 suggests a structural role for these residues, part of a series of predicted beta-sheet sequences in the C-terminal third of the LCAT primary sequence.

Lecithin-cholesterol acyltransferase: effects of mutagenesis at N-linked oligosaccharide attachment sites on acyl acceptor specificity

Site-directed mutagenesis was used to generate lecithin-cholesterol acyltransferase (LCAT) species in which individual attachment sites for N-linked oligosaccharide residues were replaced with residues that prevent the attachment of carbohydrate. Mutants at three of four sites retained significant acyltransferase activity, and phospholipase activity in the absence of cholesterol. Mutation at one site (asn272) converted LCAT to a phospholipase generating fatty acids not cholesteryl esters.

Beta-thalassemia mutations in Indonesia and their linkage to beta haplotypes

A total of 72 chromosomes from 36 Indonesian patients, 23 with beta-thalassemia major and 13 with Hb E-beta-thalassemia, were analyzed by specific oligonucleotide hybridization after DNA amplification. Thirteen had the beta E mutation (codon 26 GAG----AAG). Of the 59-beta-thalassemic chromosomes, 32 were of the variant IVS-1 nt5 (G----C). Seven had the mutation IVS-2 nt654 (C----T), one had the mutation codon 41/42 (deletion CTTT), and one had the mutation codon 17 (AAG----TAG). Another six with the mutation IVS-1 nt1 (G----T), one with the mutation IVS-1 nt1 (G----A), four with the mutation codon 15 (TGG----TAG), one with a mutation codon 30 (AGG----ACG), and one with a mutation codon 35 (deletion C) were first identified by direct sequencing of a patient's genomic DNA followed by further hybridizing other patients' DNA with the appropriate oligonucleotide probes. Five did not carry the common mutations previously described in Asian populations. The four most prevalent mutations encountered made up 83% of the total number of beta-thalassemic chromosomes studied. The most common mutation, IVS-1 nt5 (G----C), was mostly associated with two different haplotypes.