A Review of Magnetic Particle Imaging and Perspectives on Neuroimaging.

Magnetic particle imaging is an emerging tomographic technique with the potential for simultaneous high-resolution, high-sensitivity, and real-time imaging. Magnetic particle imaging is based on the unique behavior of superparamagnetic iron oxide nanoparticles modeled by the Langevin theory, with the ability to track and quantify nanoparticle concentrations without tissue background noise. It is a promising new imaging technique for multiple applications, including vascular and perfusion imaging, oncology imaging, cell tracking, inflammation imaging, and trauma imaging. In particular, many neuroimaging applications may be enabled and enhanced with magnetic particle imaging. In this review, we will provide an overview of magnetic particle imaging principles and implementation, current applications, promising neuroimaging applications, and practical considerations.

Defective eyelid leading edge cell migration in C57BL/6-corneal opacity mice with an "eye open at birth" phenotype.

Development of the eyelid requires coordination of the cellular processes involved in proliferation, cell size alteration, migration, and cell death. C57BL/6J-corneal opacity (B6-Co) mice are mutant mice generated by the administration of N-ethyl-N-nitrosourea (100 mg/kg). They exhibit the eyelids open at birth phenotype, abnormal round cell shape from tightened F-actin bundles in leading edge keratinocytes at E16.5, and gradual corneal opacity with neovessels. The tip of the leading edge in B6-Co mice did not move forward, and demonstrated a sharp peak shape without obvious directionality. Analysis of the biological characteristics of B6-Co mice demonstrated that abnormal migration of keratinocytes could affect eyelid development, but proliferation and apoptosis in B6-Co mice had no effect. Mutant gene mapping and sequence analysis demonstrated that in B6-Co mice, adenosine was inserted into the untranslated regions, between 3030 and 3031, in the mRNA 3'-terminal of Fgf10. In addition, guanine 7112 was substituted by adenine in the Mtap1B mRNA, and an A2333T mutation was identified in Mtap1B. Quantitative real-time polymerase chain reaction analysis showed that expression of the Hbegf gene was significantly down-regulated in the eyelids of B6- Co mice at E16.5, compared to B6 mice. However, the expression of Rock1, Map3k1, and Jnk1 genes did not show any significant changes. Abnormal keratinocyte migration and down-regulated expression of the Hbegf gene might be associated with impaired eyelid development in B6-Co mice.

Altered circulating endothelial progenitor cells in patients with keloid.

Evidence has suggested that vascular endothelial growth factor (VEGF), a crucial growth factor in regulating endothelial progenitor cells (EPCs), plays a central role in keloid formation. However, the levels of circulating EPCs in patients with keloid have not yet been explored. The aim of this study was to determine the number of circulating EPCs in patients with keloid. Circulating EPCs (defined as CD45- CD34+CD133+VEGFR2+cells) and VEGF levels from 39 patients with keloid and 22 healthy controls (HCs) were assessed by flow cytometry and ELISA, respectively. EPCs were detectable in the peripheral blood of patients with keloid. The number of circulating EPCs and the levels of plasma VEGF were significantly higher in patients with keloid than in HCs. However, no correlation was found between the number of circulating EPCs and the serum VEGF levels. This study provides the first evidence that EPCs are increased in the peripheral blood of patients with keloid. Understanding the roles of EPCs in keloid fromation may lead to the development of novel therapeutic strategies for keloid.

Tumour budding is a reproducible index for risk stratification of patients with stage II colon cancer.

AIM: High-risk patients with Stage II colon cancer may benefit from adjuvant chemotherapy, but it is difficult to identify such a patient group. A robust and reproducible index would be helpful to select the subset of Stage II colon cancer patients at high risk. This study investigated the potential prognostic significance of tumour budding in Stage II colon cancer. METHOD: In all, 135 Stage II colon cancer patients with known outcome were identified. The degree of tumour budding was assessed by two individual observers and was classified, according to the number of tumour buds in the area with the greatest budding intensity on haematoxylin and eosin slides, as high-grade budding (10 or more tumour buds) and low-grade budding (0-9 buds). Inter-observer agreement for two observers was assessed by using the kappa test. Progression-free and cancer-specific survivals were analysed using the Kaplan-Meier method and Cox regression. RESULTS: The 5-year progression-free survival rates for patients with high-grade tumour budding (n = 36) and those with low-grade budding (n = 99) were 57.6% and 89.0% (P < 0.001). The 5-year cancer-specific survival rates were 66.7% vs 92.0% (P < 0.001). Cox regression analyses demonstrated tumour budding as an independent predictor of disease progression (hazard ratio 4.982, P < 0.001) and cancer-related death (hazard ratio 4.142, P = 0.003). The two observers agreed on the classification of tumour budding in 118 cases (87.4%) and the inter-observer agreement was good (κ = 0.692). CONCLUSION: Tumour budding is a strong and reproducible prognostic factor for adverse outcome in Stage II colon cancer, which may serve as a prognostic marker to identify patients with a high risk of recurrence who may benefit from adjuvant therapy.

Adoptive immunotherapy for postoperative hepatocellular carcinoma: a systematic review.

The high risk of recurrence in post-operative hepatocellular carcinoma (HCC) highlights the need for an effective adjuvant treatment. A systematic review of randomised controlled trials (RCTs) was performed to evaluate the clinical efficacy of adjuvant adoptive immunotherapy (AIT) for post-operative HCC patients. Electronic (MEDLINE, EMBASE and Cochrane Library databases) and manual searches were conducted throughout May 2011 to identify RCTs evaluating postoperative AIT for patients with HCC. Methodological quality was assessed in accordance with the QUOROM statement. Four RCTs totalling 423 patients met the eligibility criteria. All RCTs reported significantly improved disease-free survival rate or reduced recurrence rate after treating with adjuvant AIT (p < 0.05). The overall survival rates of AIT group are slightly higher than those of the control group in one study. Moreover, AIT was a safe treatment, with fever as the main adverse effects. This study adds to the evidence that postoperative HCC patients treated with adjuvant AIT show an improvement in disease-free survival rate or recurrence rate.

Methyl tert-butyl ether (MTBE) degradation by ferrous ion-activated persulfate oxidation: feasibility and kinetics studies.

The objective of this study was to evaluate the feasibility of using ferrous ion-activated persulfate oxidation to remediate groundwater contaminated with methyl tert-butyl ether (MTBE). In this study, batch experiments were conducted to evaluate the effects of various factors on the efficiency of MTBE degradation including persulfate concentrations, ferrous ion concentrations, and persulfate coupled with hydrogen peroxide. Results show that ferrous ion-activated persulfate oxidation was capable of degrading MTBE efficiently. Persulfate and ferrous ion concentrations correlated with MTBE degradation rates. However, excess addition of ferrous ion resulted in decreased MTBE degrading rates most likely because of competition for sulfate free radicals between ferrous ion and MTBE. Two main byproducts of MTBE degradation, tert-butyl formate and tert-butyl alcohol, were detected in the experiments; both were, however, subsequently degraded. Results of sulfate analysis show that proper addition of ferrous ion could prevent unnecessary persulfate decomposition.

Aquagenic syringeal acrokeratoderma in an adult man: case report and review of the literature.

Aquagenic syringeal acrokeratoderma (ASA) is a rare acquired disorder that develops predominantly in young women. It is clinically characterized by a burning sensation and whitish discolouration on the hands and rarely on the soles after brief immersion in water, which resolves within a short time after drying. Topical aluminium chloride and salicylic acid are reportedly beneficial in some cases. In total, 20 female and 8 male patients with ASA have been reported previously. We present another male patient, who failed to respond to treatment with antihistamines and topical steroids, but responded well to formalin 3% in alcohol without any side-effects.

Inactivation of human SRBC, located within the 11p15.5-p15.4 tumor suppressor region, in breast and lung cancers.

A cDNA clone encoding human SRBC [serum deprivation response factor (sdr)-related gene product that binds to c-kinase] was isolated in a yeast two-hybrid screening, with amino acids 1-304 of BRCA1 as the probe. The human SRBC gene (hSRBC) was mapped to chromosome region 11p15.5-p15.4, close to marker D11S1323, at which frequent loss of heterozygosity (LOH) has been observed in sporadic breast, lung, ovarian, and other types of adult cancers as well as childhood tumors. hSRBC-coding region mutations including frame shift and truncation mutations were detected in a few ovarian and lung cancer cell lines. More significantly, the expression of hSRBC protein was down-regulated in a large fraction [30 (70%) of 43] of breast, lung, and ovarian cancer cell lines, whereas strong expression of hSRBC protein was detected in normal mammary and lung epithelial cells. The down-regulation of hSRBC expression in cancer cells was associated with hypermethylation of CpG dinucleotides in its promoter region, and 3 (60%) of 5 primary breast tumors and 11 (79%) of 14 primary lung tumors were also found to be hypermethylated. Treatment of breast cancer MCF7 cells with 5'azacytidine and Trichostatin A resulted in expression of hSRBC, confirming DNA methylation as the mode of inactivation. Our results suggest that epigenetic or mutational inactivation of hSRBC may contribute to the pathogenesis of several types of human cancers, marking hSRBC as a candidate tumor suppressor gene.

Optimized protocols in terms of equalizing the true and accidental coincidences of each bed position in static multiple bed position carbon-11 PET studies and a target single bed position study.

Quantitative carbon-11 (11C) positron emission tomography (PET) is gaining more attention in oncological applications. In addition, it was discovered that accidental coincidences (randoms) can play an important role in studies such as partial volume effects correction without needing to use anatomical information. However, because of the short half-life of 11C, a homogeneous multiple bed position 11C image is hard to obtain. This study aimed to determine whether innovative pseudogating, optimized pseudogating and optimized double-up methods could match the true counts and randoms to each bed position and to a target single bed position study. A long cylindrical phantom filled with [11C]acetate was scanned by a dedicated PET scanner using six protocols: whole body, frame-duration-compensated whole body, double-up, optimized double-up, pseudogating, and optimized pseudogating. The differences between the protocols are in the initial activity, frame duration and frame number for each bed position. The parameters for pseudogating were determined according to the theory that true counts and randoms are proportional to the radioactivity and its square, respectively. The results show that the stated goals could only be achieved by pseudogating and optimized pseudogating. We conclude that pseudogating or optimized pseudogating must be applied for a critical quantitative study. However, optimized double-up and double-up methods are good alternatives for semi-quantitative and qualitative studies, respectively.

Characterization of Sp1, AP-1, CBF and KRC binding sites and minisatellite DNA as functional elements of the metastasis-associated mts1/S100A4 gene intronic enhancer.

The mts1/S100A4 gene encodes a small acidic calcium-binding protein that is expressed in a cell-specific manner in development, tumorigenesis and certain tissues of adult mice. A composite enhancer that is active in murine mammary adenocarcinoma cells was previously identified in the first intron of the mts1/S100A4 gene. Here we present a detailed analysis of the structure and function of this enhancer in the Mts1/S100A4-expressing CSML100 and non-expressing CSML0 mouse adenocarcinoma cell lines. In CSML100 cells the enhancer activity is composed of at least six cis-elements interacting with Sp1 and AP-1 family members and CBF/AML/PEBP2 and KRC transcription factors. In addition, a minisatellite-like DNA sequence significantly contributes to the enhancer activity via interaction with abundant proteins, which likely have been described previously under the name minisatellite-binding proteins. Extensive mutational analysis of the mts1/S100A4 enhancer revealed a cooperative function of KRC and the factors binding minisatellite DNA. This is the first example of an enhancer where two nuclear factors earlier implicated in different recombination processes cooperate to activate transcription. In Mts1/S100A4-negative CSML0 cells the strength of the enhancer was 7- to 12.5-fold lower compared to that in CSML100 cells, when referred to the activities of three viral promoters. In CSML0 cells the enhancer could be activated by exogenous AP-1 and CBF transcription factors.

[Molecular cloning and expression of the cDNA encoding angiogenesis inhibitor K4K5 with Pichia pastoris].

Kringles of human plasminogen except kringle 4 can inhibit the endothelial cell growth. To determine whether recombinant plasminogen kringle 4-5 (r-K4K5) can inhibit the growth of bovine capillary endothelial (BCE) cell and the angiogenesis of chick embryo chorioallantoic membrane (CAM), we cloned and constructed the modified cDNA region encoding kringles 4 and 5 (K4K5) of human plasmin (ogen) and expressed it with pichia multi-copy expression system. One clone, with the most productive expression was selected from hundreds of transformants. Our data showed that the expression product r-K4K5 (MW 21.5 kD) amounted to 150-250 mg/liter, over 80% of the total secreted protein. It could, dose-dependently, inhibit BCE cell proliferation and inhibit chick embryo CAM angiogenesis.

In vitro and in vivo suppression of growth of rat liver epithelial tumor cells by antisense oligonucleotide against protein kinase C-alpha.

BACKGROUND/AIMS: It has been hypothesized that liver stem cells may be activated and proliferate upon liver injury and may participate in the development of liver cancer. GP7TB, a rat liver epithelial tumor cell line, possesses characteristics of liver stem-like cells and can develop into a tumor in syngeneic Fischer 344 rat. We found that protein kinase C-alpha (PKC-alpha) is overexpressed in GP7TB cells. The importance of PKC-alpha for this liver tumor cell was elucidated. METHODS: Antisense oligonucleotide (ODN) was applied to suppress the production of PKC-alpha in GP7TB cells in vitro and in vivo. Cell viability was measured by acid phosphatase assay. The cellular levels of PKC-alpha and Bcl-2 were monitored by Western-blot analysis. Activation of nuclear factor NF-kappaB was analyzed by electrophoretic mobility shift assay. Cell cycle phase distribution was monitored by FACScan. Cell apoptosis was detected by TUNEL assay and histochemical staining of tumor tissue sections. The in vivo experiment was conducted by implanting tumor mass of GP7TB in the liver of F-344 rat and continuous delivery of the ODN by a mini-osmotic pump. RESULTS: Antisense ODN effectively suppressed the level of PKC-alpha that resulted in the decrease of Bcl-2 and nuclear NF-kappaB. The cumulative viable cells also decreased dramatically for the antisense-treated group. FACScan showed that the cells were arrested at early S-phase. These cells in turn went into apoptosis without completing a cell cycle. It was found that growth of the tumor was suppressed efficiently by antisense ODN. Cell apoptosis was found in the orthotopic tumor. The normal liver cells were not affected. CONCLUSIONS: A lethal effect of depressing the level of PKC-alpha in GP7TB cells and success in suppressing orthotopic tumor growth in vivo suggests that PKC-alpha antisense ODN would be a promising therapeutic agent for some liver cancers.

The kappaB and V(D)J recombination signal sequence binding protein KRC regulates transcription of the mouse metastasis-associated gene S100A4/mts1.

A kappaB-like sequence, Sb, is integral to the composite enhancer located in the first intron of the metastasis-associated gene, S100A4/mts1. Oligonucleotides containing this sequence form three specific complexes with nuclear proteins prepared from S100A4/mts1-expressing CSML100 adenocarcinoma cells. Protein studies show the Sb-interacting complexes include NF-kappaB/Rel proteins, p50.p50 and p50.p65 dimers. Additionally, the Sb sequence was bound by an unrelated approximately 200-kDa protein, p200. Site-directed mutagenesis in conjunction with transient transfections indicate that p200, but not the NF-kappaB/Rel proteins, transactivates S100A4/mts1. To identify candidate genes for p200, double-stranded DNA probes containing multiple copies of Sb were used to screen a randomly primed lambdagt11 cDNA expression library made from CSML100 poly(A)(+) RNA. Two clones corresponding to the DNA-binding proteins KRC and Alf1 were identified. KRC encodes a large zinc finger protein that binds to the kappaB motif and to the signal sequences of V(D)J recombination. In vitro DNA binding assays using bacterially expressed KRC fusion proteins, demonstrate specific binding of KRC to the Sb sequence. In addition, introduction of KRC expression vectors into mammalian cells induces expression of S100A4/mts1 and reporter genes driven by S100A4/mts1 gene regulatory sequences. These data indicate that KRC positively regulates transcription of S100A4/mts1.

11C-acetate clearance in nasopharyngeal carcinoma.

This study assessed 11C-acetate turnover (clearance) in nasopharyngeal carcinoma (NPC). Data were acquired by dynamic PET after the intravenous injection of 4.625 MBq.kg-1 body weight of 11C-acetate for 30 min. Tomograms were reconstructed and evaluated visually. A time-activity curve of the nasopharynx and neck was generated and the clearance rate of 11C-acetate from the nasopharynx in the slow phase and from NPC was calculated using 0.693/T1/2. Ten patients with nasopharyngeal carcinoma and nine normal subjects were studied. The clearance of 11C-acetate from the normal nasopharynx was rapid and biexponential, in contrast to the rapid uptake followed by extremely slow clearance in patients with NPC. The clearance rate (mean +/- S.D.) was 0.0074 +/- 0.0042 in NPC and 0.0263 +/- 0.0152 in controls in the slow phase, being significantly different between the two groups with no overlap. All nasopharyngeal carcinomas were clearly visualized, in contrast to no obvious retention in the normal nasopharynx. Our initial results indicate that 11C-acetate clearance can be used to differentiate nasopharyngeal carcinoma from a normal nasopharynx. This finding may lead to new applications of 11C-acetate in oncology.

Regulation by phosphorylation of the zinc finger protein KRC that binds the kappaB motif and V(D)J recombination signal sequences.

The DNA binding protein KRC (forkappaB binding andrecognitioncomponent of the V(D)J recombination signal sequence) belongs to a family of large zinc finger proteins that bind to the kappaB motif and contains two widely separated DNA binding structures. In addition to the kappaB motif, KRC fusion proteins bind to the signal sequences of V(D)J recombination to form highly ordered complexes. Here, we report that KRC may be regulated by post-translational modifications. Specific protein kinases present in the nucleus of pre-B cells phosphorylated a KRC fusion protein at tyrosine and serine residues. Such protein modifications increased DNA binding, thereby providing a mechanism by which KRC responds to signal transduction pathways. KRC is a substrate of epidermal growth factor receptor kinase and P34cdc2 kinase in vitro. Our results suggest that activation of the KRC family of transcription factors may provide a mechanism by which oncogenic tyrosine kinases regulate genes with kappaB-controlled gene regulatory elements.

The C-terminal (BRCT) domains of BRCA1 interact in vivo with CtIP, a protein implicated in the CtBP pathway of transcriptional repression.

The BRCA1 tumor suppressor encodes a polypeptide with two recognizable protein motifs: a RING domain near the N terminus and two tandem BRCT domains at the C terminus. Studies of tumor-associated mutations indicate that the RING and BRCT sequences are required for BRCA1-mediated tumor suppression. In addition, recent work has shown that BRCA1 is a potent regulator of RNA transcription and that the BRCT domains are also essential for this activity. Therefore, we used the Sos recruitment system to screen for proteins that bind this critical region of BRCA1. Our results show that the BRCT domains interact in vivo with CtIP, a protein originally identified on the basis of its association with the CtBP transcriptional co-repressor. This finding suggests that BRCA1 regulates gene expression, at least in part, by modulating CtBP-mediated transcriptional repression. Moreover, the in vivo interaction between BRCA1 and CtIP is completely ablated by each of three independent tumor-associated mutations affecting the BRCT motifs of BRCA1. These results indicate that the BRCA1-CtIP interaction may be required for tumor suppression by BRCA1.

Identification of a RING protein that can interact in vivo with the BRCA1 gene product.

The hereditary breast and ovarian cancer gene, BRCA1, encodes a large polypeptide that contains the cysteine-rich RING motif, a zinc-binding domain found in a variety of regulatory proteins. Here we describe a novel protein that interacts in vivo with the N-terminal region of BRCA1. This BRCA1-associated RING domain (BARD1) protein contains an N-terminal RING motif, three tandem ankyrin repeats, and a C-terminal sequence with significant homology to the phylogenetically conserved BRCT domains that lie near the C terminus of BRCA1. The BARD1/BRCA1 interaction is disrupted by BRCA1 missense mutations that segregate with breast cancer susceptibility, indicating that BARD1 may be involved in mediating tumour suppression by BRCA1.