Comparison of Fourier and wavelet resampling methods.

Resampling can be used to compute the null distribution of any test statistic for the purpose of measuring the significance of the measured value. This study investigated how well the spatial and temporal correlations of simulated and experimentally observed fMRI time series were preserved under Fourier and wavelet resampling methods. The null distributions of a test statistic estimated by each resampling method were compared. In addition, both resampling methods were applied to locate activated voxels in an fMRI dataset and ROC analysis showed that wavelet resampling performed more accurately than Fourier resampling.     

Pharmacokinetic characterization in xenografted mice of a series of first-generation mimics for HLA-DR antibody, Lym-1, as carrier molecules to image and treat lymphoma.

Despite their large size, antibodies (Abs) are suitable carriers to deliver systemic radiotherapy, often molecular image-based, for lymphoma and leukemia. Lym-1 Ab has proven to be an effective radioisotope carrier, even in small amounts, for targeting human leukocyte antigen DR (HLA-DR), a surface membrane protein overexpressed on B-cell lymphoma. Pairs of molecules (referred to as ligands), shown by computational and experimental methods to bind to each of 2 sites within the Lym-1 epitopic region, have been linked to generate small (<2 kDa) molecules (referred to as selective high-affinity ligands [SHALs]) to mimic the targeting properties of Lym-1 Ab. METHODS: A lysine-polyethylene glycol (PEG) backbone was used to synthetically link 2 of the following ligands: deoxycholate, 5-leuenkephalin, triiodothyronine, thyronine, dabsyl-L-valine, and N-benzoyl-L-arginyl-4-amino-benzoic acid to generate a series of 13 bidentate SHALs with a biotin or 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid (DOTA) chelate attached to the linker. These SHALs have been assessed for their selectivity in binding to HLA-DR10-expressing cells and for their pharmacokinetics and tissue biodistribution in mice. Biotinylated versions of these SHALs discriminated cell lines positive for HLA-DR10 expression with near-nanomolar affinity. The DOTA versions of 4 SHALs were labeled with (111)In for pharmacokinetic studies in mice with HLA-DR10-expressing malignant Raji xenografts. RESULTS: The bidentate, biotinylated, and DOTA-SHALs were synthesized in high-purity, multimilligram amounts. Mean radiochemical and product yields and purities were 90%, 75%, and 90% at mean specific activities of 3.9 MBq/microg (105 microCi/microg) for the (111)In-labeled SHALs. As expected, rapid blood clearance and tumor targeting were observed. The pharmacokinetics of the SHALs was influenced by the component ligands. Biliary clearance, kidney localization, and serum receptor binding contributed to less favorable tumor targeting. CONCLUSION: A series of SHALs was readily synthesized in multimilligram amounts and showed the expected selective binding in vitro. Better selection of the SHAL components should provide second-generation SHALs with improved properties to fulfill the substantial potential of these novel molecular carriers for targeting.     

Thermal dosimetry predictive of efficacy of 111In-ChL6 nanoparticle AMF--induced thermoablative therapy for human breast cancer in mice.

Antibody (mAb)-linked iron oxide nanoparticles (bioprobes) provide the opportunity to develop tumor specific thermal therapy (Rx) for metastatic cancer when inductively heated by an externally applied alternating magnetic field (AMF). To evaluate the potential of this Rx, in vivo tumor targeting, efficacy, and predictive radionuclide-based heat dosimetry were studied using (111)In-ChL6 bioprobes (ChL6 is chimeric L6) in a human breast cancer xenograft model. METHODS: Using carbodiimide, (111)In-DOTA-ChL6 (DOTA is dodecanetetraacetic acid) was conjugated to polyethylene glycol-iron oxide-impregnated dextran 20-nm particles and purified as (111)In-bioprobes. (111)In doses of 740-1,110 kBq (20-30 muCi) (2.2 mg of bioprobes) were injected intravenously into mice bearing HBT3477 human breast cancer xenografts. Pharmacokinetic (PK) data were obtained at 1, 2, 3, and 5 d. AMF was delivered 72 h after bioprobe injection at amplitudes of 1,410 (113 kA/m), 1,300 (104 kA/m), and 700 (56 kA/m) oersteds (Oe) at 30%, 60%, and 90% "on" time (duty), respectively, and at 1,050 Oe (84 kA/m) at 50% and 70% duty over the 20-min treatment. Treated and control mice were monitored for 90 d. Tumor total heat dose (THD) from activated tumor bioprobes was calculated for each Rx group using (111)In-bioprobe tumor concentration and premeasured particle heat response to AMF amplitudes. Tumor growth delay was analyzed by Wilcoxon rank sum comparison of time to double, triple, and quintuple tumor volume in each group, and all groups were compared with the controls. RESULTS: Mean tumor concentration of (111)In-bioprobes at 48 h was 14 +/- 2 percentage injected dose per gram; this concentration 24 h before AMF treatment was used to calculate THD. No particle-related toxicity was observed. Toxicity was observed at the highest AMF amplitude-duty combination of 1,300 Oe and 60% over 20 min; 6 of 10 mice died acutely. Tumor growth delay occurred in all of the other groups, correlated with heat dose and, except for the lowest heat dose group, was statistically significant when compared with the untreated group. Electron microscopy showed (111)In-bioprobes on tumor cells and cell death by necrosis at 24 and 48 h after AMF. CONCLUSION: mAb-guided bioprobes (iron oxide nanoparticles) effectively targeted human breast cancer xenografts in mice. THD, calculated using empirically observed (111)In-bioprobe tumor concentration and in vitro nanoparticle heat induction by AMF, correlated with tumor growth delay.     

Increased tumor establishment and growth after open vs laparoscopic bowel resection in mice

Background: Surgery can suppress immune function and facilitate tumor growth. Several studies have demonstrated better preservation of immune function following laparoscopic procedures. Our laboratory has also shown that tumors are more easily established and grow larger after sham laparotomy than after pneumoperitoneum in mice. The purpose of this study was to determine if the previously reported differences in tumor establishment and growth would persist in the setting of an intraabdominal manipulation. Methods: Syngeneic mice received intradermal injections of tumor cells and underwent either an open or laparoscopic cecal resection. In study 1, the incidence of tumor development was observed after a low dose inoculum; whereas in study 2, tumor mass was compared on postoperative day 12 after a high-dose inoculum. Results: In study 1, tumors were established in 5% of control mice, 30% of laparoscopy mice, and 83% of open surgery mice (p < 0.01 for all comparisons). In study 2, open surgery group tumors were 1.5 times as large as laparoscopy group tumors (p < 0.01), which were 1.5 times as large as control group tumors (p < 0.02). Conclusion: We conclude that tumors are more easily established and grow larger after open laparoscopic bowel resection in mice. Received: 27 October 1997/Accepted: 19 January 1998     

Behavioural and neural changes after a “choice” therapy for naming deficits in aphasia: preliminary findings

Background: Anomia, difficulty producing words, is a pervasive symptom of many individuals with aphasia. We have developed a treatment for naming deficits—the Phonological Components Analysis (PCA) protocol—that has proven efficacious in improving word-finding abilities for individuals with post-stroke aphasia.

Aims: The aim of this investigation is to present preliminary findings exploring the potential influence of choice—that is the active engagement of a participant in therapy—on our PCA treatment.

Methods & Procedures: Five individuals with aphasia were treated in one of two conditions—Choice or No Choice. Potential changes in neural activation as a function of the treatment were also investigated. Two individuals (one from each condition) underwent functional MRI (fMRI) pre- and post-therapy.

Outcomes & Results: All the individuals demonstrated a significant treatment effect immediately post-treatment and at a 4-week follow-up and four of the five participants at an 8-week follow-up. Three also demonstrated generalisation to untrained items. Unfortunately, no clear-cut patterns emerged to allow us to make claims about the influence of choice, per se, on the behavioural manifestations of improved naming. Interestingly, the participant from the Choice condition showed neural activation changes post-treatment in frontal and parietal regions that were not evident for the participant in the No Choice condition. Moreover, these changes were accompanied by a larger treatment effect for that individual and generalisation to a novel naming task.

Conclusion: The efficacy of PCA treatment for naming deficits is further supported. In addition, the neuroimaging data suggest the possibility that active engagement of an individual in his/her therapy (in this case choosing phonological attributes of a target word) may exercise executive functions important for success in treating anomia. Also, continued exploration of task factors that may promote even better treatment effects using this protocol is warranted, as is continued investigation of the neural underpinnings associated with treatment effects.     

Automation of the ELISpot assay for high-throughput detection of antigen-specific T-cell responses

The enzyme linked immunospot (ELISpot) assay is a fundamental tool in cellular immunology, providing both quantitative and qualitative information on cellular cytokine responses to defined antigens. It enables the comprehensive screening of patient derived peripheral blood mononuclear cells to reveal the antigenic restriction of T-cell responses and is an emerging technique in clinical laboratory investigation of certain infectious diseases. As with all cellular-based assays, the final results of the assay are dependent on a number of technical variables that may impact precision if not highly standardised between operators. When studies that are large scale or using multiple antigens are set up manually, these assays may be labour intensive, have many manual handling steps, are subject to data and sample integrity failure and may show large inter-operator variability. Here we describe the successful automated performance of the interferon (IFN)-γ ELISpot assay from cell counting through to electronic capture of cytokine quantitation and present the results of a comparison between automated and manual performance of the ELISpot assay. The mean number of spot forming units enumerated by both methods for limiting dilutions of CMV, EBV and influenza (CEF)-derived peptides in six healthy individuals were highly correlated (r > 0.83, p < 0.05). The precision results from the automated system compared favourably with the manual ELISpot and further ensured electronic tracking, increased through-put and reduced turnaround time.     

Progressive behavioral deficits in DJ-1-deficient mice are associated with normal nigrostriatal function

Loss-of-function mutations in the DJ-1 gene account for an autosomal recessive form of Parkinson's disease (PD). To investigate the physiological functions of DJ-1 in vivo, we generated DJ-1 knockout (DJ-1^−/−) mice. Younger (< 1 year) DJ-1^−/− mice were hypoactive and had mild gait abnormalities. Older DJ-1^−/−, however, showed decreased body weight and grip strength and more severe gait irregularities compared to wild-type littermates. The basal level of extracellular dopamine, evoked dopamine release and dopamine receptor D2 sensitivity appeared normal in the striatum of DJ-1^−/− mice, which was consistent with similar results between DJ-1^−/− and controls in behavioral paradigms specific for the dopaminergic system. An examination of spinal cord, nerve and muscle tissues failed to identify any pathological changes that were consistent with the noted motor deficits. Taken together, our findings suggest that loss of DJ-1 leads to progressive behavioral changes without significant alterations in nigrostriatal dopaminergic and spinal motor systems.     

Detectability of fifteen aquatic micro/mesocosms

Zooplankton abundance and species richness in 15 untreated 12,000 L outdoor microcosms (n = 15) were monitored over the course of 1 year to document the inherent variability and statistical detectability between replicates. Statistical power analysis were applied to derive the statistically minimal detectable difference (MDD) between replicates with default values set at; α = 0.1 and β = 0.2. Copepod abundance and species richness generally demonstrated the best detectability at 0.31 and 0.16, respectively, (n = 15); 0.59 and 0.33 (n = 3). Total zooplankton abundance and species richness had the lowest detectabilities at 0.19 and 0.14, respectively, (n = 15); 0.35 and 0.3 (n = 3). Rotifers, due to their opportunistic and rapid life traits, had the lowest single-species abundance detectabilities at 0.54 (n = 15); 0.8 (n = 3), whereas macroinvertebrate species richness had the lowest detectability at 0.43 (n = 15); 0.7 (n = 3) over 1 year. We recommend a priori calibration of the study design relative to relevant MDDs. Moreover, it is suggested to consider alternatives to statistical null hypothesis testing.     

The methylenetetrahydrofolate reductase C677T mutation induces cell‐specific changes in genomic DNA methylation and uracil misincorporation: A possible molecular basis for the site‐specific cancer risk modification

The C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with a decreased risk of colon cancer although it may increase the risk of breast cancer. This polymorphism is associated with changes in intracellular folate cofactors, which may affect DNA methylation and synthesis via altered one‐carbon transfer reactions. We investigated the effect of this mutation on DNA methylation and uracil misincorporation and its interaction with exogenous folate in further modulating these biomarkers of one‐carbon transfer reactions in an in vitro model of the MTHFR 677T mutation in HCT116 colon and MDA‐MB‐435 breast adenocarcinoma cells. In HCT116 cells, the MTHFR 677T mutation was associated with significantly increased genomic DNA methylation when folate supply was adequate or high; however, in the setting of folate insufficiency, this mutation was associated with significantly decreased genomic DNA methylation. In contrast, in MDA‐MB‐435 cells, the MTHFR 677T mutation was associated with significantly decreased genomic DNA methylation when folate supply was adequate or high and with no effect when folate supply was low. The MTHFR 677T mutation was associated with a nonsignificant trend toward decreased and increased uracil misincorporation in HCT116 and MDA‐MB‐435 cells, respectively. Our data demonstrate for the first time a functional consequence of changes in intracellular folate cofactors resulting from the MTHFR 677T mutation in cells derived from the target organs of interest, thus providing a plausible cellular mechanism that may partly explain the site‐specific modification of colon and breast cancer risks associated with the MTHFR C677T mutation. © 2008 Wiley‐Liss, Inc.