Enhancement of the mechanical properties of organic-inorganic hybrid elastomers by introducing movable and reversible crosslinks.

Organic-inorganic materials have been widely utilized in various fields as multifunctional materials. Poly(dimethyl siloxane) (PDMS), a typical inorganic polymer, has industrially appealing functions, such as transparency, biocompatibility, and gas permeability; however, it has poor mechanical properties. We incorporated organic-inorganic hybrid elastomers (PDMS-γCD-AAl⊃P(EA-HEMA) (x)) with movable crosslinks, and we utilized hydrogen bonds as reversible crosslinks. The organic polymer poly ethyl acrylate-r-hydroxy ethyl methacrylate (P(EA-HEMA)) penetrated the cavity of triacetylated γ-cyclodextrin (γCD), which was introduced into the side chains of PDMS, and it compounded with PDMS at the nanoscale. Structural studies involving visual and X-ray scattering measurements revealed that movable crosslinks improved the compatibility levels of PDMS and acrylate copolymers. However, macroscopic phase separation occurred when the number of reversible crosslinks increased. Furthermore, studies on the mobility levels of acrylate copolymers and movable crosslinks indicated that the relaxation behaviour of PDMS-γCD-AAl⊃P(EA-HEMA) (x) changed with changing numbers of reversible crosslinks. Introducing reversible crosslinks improved the Young's modulus and toughness values. The movable and reversible crosslinks between the organic and inorganic polymers contributed to the high elongation properties. The design of PDMS-γCD-AAl⊃P(EA-HEMA) (x) incorporated cooperatively movable and reversible crosslinks to achieve high compatibility of immiscible polymers and to control the mechanical properties.

[A Study of Patient's Dose Control at Radiography by Using a Dose Area Product Meter].

PURPOSE: The International Commission on Radiological Protection recommends adaptation of the diagnostic reference levels (DRLs). Japan DRLs 2020 apply the entrance surface dose (ESD) in radiography. However, it is difficult to measure ESD in the clinical setting. A dose area product meter has been proposed for use as a dose index in interventional radiology. We investigated the basic characteristic of a dose area product meter and the relationship of ESD and dose area product meter values in radiography. METHOD: We measured calibration factors from phantom studies and estimated ESD from the dose area product meter. Subject thickness was measured from the chest clinical images for calculation of ESD. Estimated ESD from the dose area product meter was compared with that calculated from program software (Surface Dose Evaluation Code, Sdec). RESULT: Relative dose (dose area product meter/ionization chamber) decreased when tube voltage was lower (60 kV) or higher (130 kV). A positive correlation was found between the estimated and calculated ESD. CONCLUSION: Dose area product meter can be used for patient's dose control in radiography.

[Usefulness of Combining Post-processing Scatter Correction and an Anti-scatter Grid in Chest Standing Radiography].

PURPOSE: The aim of this study was to evaluate the usefulness of combining post-processing scatter correction (IG) and an anti-scatter grid (RG) in chest radiography. METHOD: To determine the combination protocol (Hyb) that was closed to RG 12:1 (RG12), we measured the content rate of scattered radiation for each combination (RG12, IG12, RG3-12+IG3-12). Task-based modulation transfer function (MTF_Task) and SDNR were evaluated using RG12, IG12, and Hyb. Additionally, seven radiologists performed visual evaluation by using chest phantom. RESULT: The protocol of Hyb was RG8+IG3. In SDNR, Hyb (RG8+IG3) was equal to or higher than RG12, and MTF_Task was equal in all grid systems. Hyb (RG8+IG3) was significantly superior to RG12 in visual evaluation. CONCLUSION: The combining post-processing scatter correction should be useful for improving inspection throughput and reducing the risk of grid's damage.

[Examination of the Maximum Brightness of the Monitor Suitable for Radiological Technologists' Interpretation Assistance and Image Inspection].

The purpose of this study is to examine the maximum brightness of the monitor, which is suitable for radiological technologists' (hereinafter referred to as technicians) interpretation assistance and image inspection. The signal detection ability was evaluated by receiver operating characteristic (ROC) analysis using a chest X-ray image with a simulated nodule. In order to examine the ease of observation and the effect on the subjective evaluation by changing the maximum brightness, evaluation was performed by the normalized ranking method using chest X-ray images. ROC experiments were performed using images with and without simulated nodules in the chest phantom. There was no significant difference in detectability by changing the maximum brightness (p>0.05), but the average area under the curve (AUC) was higher at 350 cd/m2 than at 100 cd/m2 and 170 cd/m2. A normalized ranking method was performed focusing on simulated nodules on chest X-ray images. In the least significant difference (l.s.d.) method, there was a significant difference between the maximum luminance, and the higher the maximum luminance, the better the evaluation. From these results, the change in the maximum brightness did not significantly affect the signal detection ability of the technician's chest X-ray image, but the higher the maximum brightness, the easier it was to observe and the higher the subjective evaluation. It has been reported that the higher the maximum brightness, the shorter the signal recognition time, and a monitor with a high maximum brightness may lead to more efficient image inspection by a technician. From the results of this study, it is considered appropriate to use a medical liquid crystal display (LCD) monitor with a maximum brightness of 350 cd/m2 for the technician's interpretation assistance and image inspection.

[Comparison of Detectability for the New Image Processing and Conventional Image Processing by ROC Analysis: A Phantom Study of Chest Radiography].

The purpose of this study is to compare the detectability of diseases the new image processing and the conventional image processing by receiver operating characteristic (ROC) analysis and to show the usefulness of the new image processing. Radiographs with and without nodular cancer models in the chest phantom were used for observation samples. Totally 200 radiographs were evaluated by 10 radiological technologists (each readers had over 20 years or under 4 years of experience). The mean area under the curve (AUC) calculated from the over 20 years group was 0.754 for the new processing and 0.771 for the conventional processing (p value=0.651, 95% confidence interval=-0.084/0.049 (lower bound/upper bound)). On the other hand, the average AUC calculated from under 4 years group was 0.819 for the new processing and 0.678 for the conventional processing (p value= 0.041, 95% confidence interval=0.019/0.262 (lower bound/upper bound)). New image processing provides high detectability in less than 4 years group compared to conventional processing.

CNPY2 inhibits MYLIP-mediated AR protein degradation in prostate cancer cells.

The androgen receptor (AR) is a ligand-dependent transcription factor that promotes prostate cancer (PC) cell growth through control of target gene expression. This report suggests that Canopy FGF signaling regulator 2 (CNPY2) controls AR protein levels in PC cells. We found that AR was ubiquitinated by an E3 ubiquitin ligase, myosin regulatory light chain interacting protein (MYLIP) and then degraded through the ubiquitin-proteasome pathway. CNPY2 decreased the ubiquitination activity of MYLIP by inhibition of interaction between MYLIP and UBE2D1, an E2 ubiquitin ligase. CNPY2 up-regulated gene expression of AR target genes such as KLK3 gene which encodes the prostate specific antigen (PSA) and promoted cell growth of PC cells. The cell growth inhibition by CNPY2 knockdown was rescued by AR overexpression. Furthermore, positive correlation of expression levels between CNPY2 and AR/AR target genes was observed in tissue samples from human prostate cancer patients. Together, these results suggested that CNPY2 promoted cell growth of PC cells by inhibition of AR protein degradation through MYLIP-mediated AR ubiquitination.

CNPY2 promoted the proliferation of renal cell carcinoma cells and increased the expression of TP53.

Renal cell carcinoma (RCC) is the most common type of kidney cancer. However, the mechanisms underlying the progression of the disease are not well understood. The data in this report suggest that canopy FGF signaling regulator 2 (CNPY2) is a promoter of RCC progression. We found that CNPY2 significantly promoted growth of RCC cells and upregulated TP53 gene expression. Although TP53 is widely known as a tumor suppressor, in RCC TP53 promoted tumor cell growth. A typical p53 target gene, CDKN1A, was upregulated by both p53 and CNPY2 in RCC cells, suggesting that CNPY2 increased the expression level of TP53. Consistent with these results, CNPY2 and TP53 expression levels were positively correlated in RCC patients. These findings suggested that CNPY2 promoted cancer cell growth in RCC through regulating TP53 gene expression.

Androgen suppresses testicular cancer cell growth in vitro and in vivo.

Silencing of androgen receptor (AR)-meditated androgen signaling is thought to be associated with the development of testicular germ cell tumors (TGCTs). However, the role of the androgen/AR signal in TGCT development has not been investigated. In this study, we show that the androgen/AR signal suppressed the cell growth of seminomas (SEs), a type of TGCT, in vitro and in vivo. Growth of SE cells was suppressed by DHT treatment and reduction of androgen levels by surgical castration promoted cancer cell growth in an in vivo xenograft model. Tryptophan hydroxylase 1 (TPH1), the rate limit enzyme in serotonin synthesis, was one of the genes which expression was reduced in DHT-treated SE cells. TPH1 was highly expressed in SE cancer tissues compared with adjacent normal tissues. Activation of androgen/AR signaling in SE cells reduced the expression of TPH1 in SE cells, followed by the reduction of serotonin secretion in cell culture supernatant. These results suggested that silencing of androgen/AR signaling may cause initiation and progression of SE through increase in TPH1 gene expression level.

Prostate Cancer Volume Estimation by Combining Magnetic Resonance Imaging and Targeted Biopsy Proven Cancer Core Length: Correlation with Cancer Volume.

PURPOSE: Multiparametric magnetic resonance imaging often underestimates or overestimates pathological cancer volume. We developed what is to our knowledge a novel method to estimate prostate cancer volume using magnetic resonance/ultrasound fusion, biopsy proven cancer core length. MATERIALS AND METHODS: We retrospectively analyzed the records of 81 consecutive patients with magnetic resonance/ultrasound fusion, targeted biopsy proven, clinically localized prostate cancer who underwent subsequent radical prostatectomy. As 7 patients each had 2 visible lesions on magnetic resonance imaging, 88 lesions were analyzed. The dimensions and estimated volume of visible lesions were calculated using apparent diffusion coefficient maps. The modified formula to estimate cancer volume was defined as the formula of vertical stretching in the anteroposterior dimension of the magnetic resonance based 3-dimensional model, in which the imaging estimated lesion anteroposterior dimension was replaced by magnetic resonance/ultrasound targeted, biopsy proven cancer core length. Agreement of pathological cancer volume with magnetic resonance estimated volume or the novel modified volume was assessed using a Bland-Altman plot. RESULTS: Magnetic resonance/ultrasound fusion, biopsy proven cancer core length was a stronger predictor of the actual pathological cancer anteroposterior dimension than magnetic resonance estimated lesion anteroposterior dimension (r = 0.824 vs 0.607, each p <0.001). Magnetic resonance/ultrasound targeted, biopsy proven cancer core length correlated with pathological cancer volume (r = 0.773, p <0.001). The modified formula to estimate cancer volume demonstrated a stronger correlation with pathological cancer volume than with magnetic resonance estimated volume (r = 0.824 vs 0.724, each p <0.001). Agreement of modified volume with pathological cancer volume was improved over that of magnetic resonance estimated volume on Bland-Altman plot analysis. Predictability was more enhanced in the subset of lesions with a volume of 2 ml or less (ie if spherical, the lesion was approximately 16 mm in diameter). CONCLUSIONS: Combining magnetic resonance estimated cancer volume with magnetic resonance/ultrasound fusion, biopsy proven cancer core length improved cancer volume predictability.

[A pediatric wilms' tumor presenting with a right renal injury].

We report a case of a pediatric Wilms' tumor presenting after a right renal injury. A 6-year-old girl presented to a nearby hospital with right back pain after a fall. An abdominal computed tomography (CT) scan revealed a right renal injury with active hemorrhaging. She was then referred to our hospital. There another CT scan and a magnetic resonance imaging (MRI) scan revealed the disappearance of the active hemorrhaging but also the presence of a large renal tumor. We performed a right nephrectomy. The renal tumor was diagnosed as a nephroblastoma. Considering dissemination by trauma, chemotherapy and radiation therapy were performed.

Paired box 2 upregulates androgen receptor gene expression in androgen-independent prostate cancer.

Androgen-independent prostate cancer is known as a hormone-refractory disease. Although the androgen receptor (AR) is considered to be a key regulator of androgen-independent prostate cancer progression, the mechanism through which AR gene expression is regulated is not well understood. In the present study, we showed that the AR gene was upregulated by paired box 2 (PAX2) in androgen-independent prostate cancer. When PAX2 upregulated AR gene expression, a decrease in DNA methylation of the AR gene locus was also observed. PAX2 was highly expressed and promoted cell growth in an androgen-independent prostate cancer cell line (22Rv1). The cell growth inhibition by PAX2 knockdown was rescued by AR overexpression in 22Rv1 cells. In a mouse xenograft model of androgen-independent prostate cancer, PAX2 knockdown inhibited tumor growth and AR gene expression and also increased DNA methylation of the AR gene. Consistent with this, AR and PAX2 expression levels were positively correlated in prostate cancer patients. These findings suggested that PAX2 promoted cancer cell growth in androgen-independent prostate cancer by regulating AR gene expression through an epigenetic mechanism.

A genetic screen in Drosophila for regulators of human prostate cancer progression.

To uncover the mechanism by which human prostate cancer progresses, we performed a genetic screen for regulators of human prostate cancer progression using the Drosophila accessory gland, a functional homolog of the mammalian prostate. Cell growth and migration of secondary cells in the adult male accessory gland were found to be regulated by paired, N-cadherin, and E-cadherin, which are Drosophila homologues of regulators of human prostate cancer progression. Using this screening system, we also identified three genes that promoted growth and migration of secondary cells in the accessory gland. The human homologues of these candidate genes - MRGBP, CNPY2, and MEP1A - were found to be expressed in human prostate cancer model cells and to promote replication and invasiveness in these cells. These findings suggest that the development of the Drosophila accessory gland and human prostate cancer cell growth and invasion are partly regulated through a common mechanism. The screening system using the Drosophila accessory gland can be a useful tool for uncovering the mechanisms of human prostate cancer progression.

Hyper-expression of PAX2 in human metastatic prostate tumors and its role as a cancer promoter in an in vitro invasion model.

BACKGROUND: Metastasis is a consequence of many biological events, during which cancer stem cells are shifted into a malignant state. Among these events, invasion of prostate cancer cells into host tissues is possible to be assessed by means of an in vitro invasion model, and is thought to be coupled to altered expression of membrane proteins. Dysregulated functions of the factors regulating organogenesis during embryogenesis are known to facilitate metastasis of many types of cancers. PAX2 (paired box 2) is a member of the PAX transcription factor family, which regulates prostatic ductal growth and branching in organogenesis of mammalian prostates. However, the role of PAX2 in prostate cancer development remains to be determined. METHODS: PAX2 expression in human prostate cancers and normal prostate epithelium were examined by quantitative RT-PCR and immunohistochemistry. Matrigel invasion assay and a gene array analysis were performed using prostate cancer cell lines transfected with either control or PAX2 siRNA. RESULTS: In human prostate cancers, PAX2 was hyper-expressed in metastatic cancers, but was expressed at lower levels in non-metastatic cancers. Consistent with this, PAX2 knockdown repressed cell growth and invasion in a Matrigel invasion assay. Gene ontology analysis revealed that many cell membrane proteins were downregulated after PAX2 knockdown. CONCLUSIONS: Our data suggested that PAX2 hyper-expression promotes the development of the metastatic state in prostate cancer cells, presumably through upregulating the expression of cell membrane proteins.

[Impact of planning CT slice thickness on the accuracy of automatic target registration using the on-board cone-beam CT].

We have evaluated relationship between planning CT slice thickness and the accuracy of automatic target registration using cone-beam CT (CBCT). Planning CT images were acquired with reconstructed slice thickness of 1, 2, 3, 5, and 10mm for three different phantoms: Penta-Guide phantom, acrylic ball phantom, and pelvic phantom. After correctly placing the phantom at the isocenter using an in-room laser, we purposely displaced it by moving the treatment couch and then obtained CBCT images. Registration between the planning CT and the CBCT was performed using automatic target registration software, and the registration errors were recorded for each planning CT data set with different slice thickness. The respective average and standard deviation of errors for 10 mm slice thickness CT in the lateral, longitudinal, and vertical directions (n=15 data sets) were: 0.7 +/- 0.2mm, 0.8 +/- 0.2mm, and 0.2 +/- 0.2mm for the Penta-Guide phantom; 0.5 +/- 0.4 mm, 0.6 +/- 0.3 mm, and 0.4 +/- 0.3 mm for the acrylic ball phantom; and 0.6 +/- 0.2 mm, 0.9 +/- 0.2 mm, and 0.2 +/- 0.2 mm for the pelvic phantom. We found that the mean registration errors were always less than 1 mm regardless of the slice thickness tested. The results suggest that there is no obvious correlation between the planning CT slice thickness and the registration errors.

Inhibitory effect of (-)-epigallocatechin 3-gallate, a polyphenol of green tea, on neutrophil chemotaxis in vitro and in vivo.

The effect of (-)-epigallocatechin 3-gallate (EGCG), a major polyphenol of green tea, on neutrophil migration has been studied using multiwell-type Boyden chambers in vitro and a fluorescein isothiocyanate-labeled ovalbumin (FITC-OVA)-induced rat allergic inflammation model in vivo. EGCG inhibited rat neutrophil chemotaxis toward cytokine-induced neutrophil chemoattractant-1 (CINC-1) in a concentration-dependent manner. In addition, CINC-1-induced neutrophil chemotaxis was suppressed by the pretreatment of rat neutrophils with EGCG at the concentration over 15 microg/mL. EGCG caused concentration-dependent suppression of the transient increase in CINC-1-induced intracellular free calcium level in both rat neutrophils and rat CXC chemokine receptor 2 (CXCR2)-transfected HEK 293 cells. EGCG inhibited CINC-1 production by IL-1beta-stimulated rat fibroblasts (NRK-49F cells) and lipopolysaccharide-stimulated rat macrophages at the concentration over 50 microg/mL, a comparatively high concentration. Oral administration of EGCG (1.0 mg or 1.5 mg/rat) at 1 h before the challenge with FITC-OVA suppressed neutrophil infiltration into the air pouch (inflammatory site) in the air-pouch type FITC-OVA-induced allergic inflammation in rats. Chemokine levels in the pouch fluids, however, were not influenced by EGCG administration. The results suggest that EGCG suppressed neutrophil infiltration by a direct action on neutrophils, but not by indirect actions, including the suppression of chemokine production at the inflammatory site.

Fibroblast growth-stimulating activity of S100A9 (MRP-14).

Fibroblasts play a critical role in chronic inflammation and wound healing. In this study, a fibroblast growth-stimulating factor was purified from the exudate of carrageenan-induced inflammation in rats. The purified protein was a disulfide-linked homodimer. Amino acid sequence analysis of the peptides generated by cleavage with cyanogen bromide and proteinase V8 resulted in identification of the protein as S100A9. Recombinant S100A9 as well as its disulfide-linked homodimer stimulated the proliferation of fibroblasts at a similar concentration of the purified protein. The concentration of S100A9 in the exudate was determined by immunoblot analysis. The total protein concentration in the exudate reached a maximum 4 days after carrageenan injection and then slightly decreased, whereas the concentration of S100A9 reached a maximum at day 3 and then decreased rapidly. These studies show that S100A9 is present at a high concentration in the exudate of carrageenan-induced inflammation in rats, and that S100A9 stimulates proliferation of fibroblasts, suggesting that it plays a role in chronic inflammation.

Chemokine receptor CXCR2 activates distinct pathways for chemotaxis and calcium mobilization.

Rat cytokine-induced neutrophil chemoattractant-3 (CINC-3) has neutrophil chemotactic activity comparable with that of CINC-1 and CINC-2, but induces calcium mobilization more potently than CINC-1 and CINC-2. However, only one CINC receptor, CXCR2, has been found in rat neutrophils. Therefore we attempted to determine the biochemical basis for the differences in neutrophil responses to CINC-1/-2 versus CINC-3. Both chemotactic activity and calcium mobilization induced by CINC-3 were desensitized by a 100-fold excess of CINC-1, which was consistent with our previous results showing that CINC-1 has 70-fold lower affinity to the receptor on rat neutrophils than CINC-3. Desensitization appeares to be reflected by the affinity of the ligands to the receptor. CINC-1- and CINC-3-induced chemotaxis was sensitive to inhibition by pertussis toxin, whereas calcium mobilization induced by CINC-1 and CINC-3 was insensitive. These results suggest that CINCs induce neutrophil chemotaxis and calcium mobilization through distinct G-proteins with different efficiency.

Identification of C3a and N-truncated C3a as vascular permeability-enhancing factors from the exudate of chronic phase of carrageenan-induced inflammation in rats.

Two basic proteins enhancing vascular permeability have been purified from the exudate of the chronic phase of carrageenan-induced inflammation in rats. One major and one minor peak on reversed-phase HPLC showed molecular masses of 9.3 kDa and 7.6 kDa, respectively, on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. NH2-terminal amino acid sequencing analysis of the purified proteins revealed that the major peak is identical to C3a, while the main sequence of the minor peak is identical to NH2-terminal 11 amino acids truncated C3a. In addition, plasmin was able to cleave C3a into the N-truncated C3a. Intradermal injection of both purified C3a and N-truncated C3a into rat skin enhanced vascular permeability, and the increased permeability was suppressed by the pretreatment with cyproheptadine. Our results suggest that the purified C3a and N-truncated C3a have the characteristics of anaphylatoxins and may contribute to exudation in the chronic phase of carrageenan-induced inflammation in rats.

Chemokine production by rat macrophages stimulated with streptolysin O from Streptococcus pyogenes.

The contribution of streptolysin O (SLO) from Streptococcus pyogenes to neutrophil infiltration in inflammatory lesions was determined by production of cytokine-induced neutrophil chemoattractant (CINC)-1, -2 and -3, and macrophage inflammatory protein (MIP)-1alpha by rat macrophages stimulated with SLO in culture. Active SLO induced the production of CINCs and MIP-1alpha in dose- and time-dependent manners. These inductions were ascertained by chemokine mRNA expression in macrophages. Streptolysin S was without effect. The SLO-cholesterol complex induced the chemokine production in proportion to the residual hemolytic activity of the complex. In addition, the effects of SLO on the chemokine production were confirmed by the injection of active SLO into the preformed air pouch on the back of rats. The infiltration of neutrophils into the pouch fluid (exudate) increased steadily with a lag phase of about 2 hr. The major chemokine found in exudates was MIP-1alpha but not CINCs. In this study, it became clear that active SLO, but not the inactive one, contributed to the production of MIP-1alpha and CINCs in the conditioned medium and in exudates.