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A selective sample cleanup method using molecularly imprinted polymers was developed for the separation of domoic acid (a shellfish toxin) from shellfish samples. The molecularly imprinted polymers for domoic acid was prepared by emulsion polymerization using 1,3,5-pentanetricarboxylic acid as the template molecule, 4-vinyl pyridine as the functional monomer, ethylene glycol dimethacrylate as the crosslinker, and Span80/Tween-80 (1:1 v/v) as the composite emulsifiers. The molecularly imprinted polymer showed high affinity to domoic acid with a dissociation constant of 13.5 μg/mL and apparent maximum adsorption capacity of 1249 μg/g. They were used as a selective sorbent for the detection of domoic acid from seafood samples coupled with high-performance liquid chromatography. The detection limit of 0.17 μg/g was lower than the maximum level permitted by several authorities. The mean recoveries of domoic acid from clam samples were 93.0-98.7%. It was demonstrated that the proposed method could be applied to the determination of domoic acid from shellfish samples.

Background and Aim: N-cadherin (N-cad), one of the classic cadherins, has been reported to be involved in tumor metastasis in some types of tumors. This study aims to investigate the expression status of N-cad in hepatocellular carcinoma (HCC) and the correlation between N-cad expression and metastatic potential, as well as the surgical outcomes of HCC. Methods: N-cad expression in HCC and adjacent liver tissues, as well as normal liver tissues, was studied by immunohistochemistry and Western blot, and the relationship between N-cad expression and the clinicopathological features of HCC was evaluated. By using RNA interference technique, the correlation of N-cad expression and metastatic potential was investigated by downregulating N-cad expression in HCCLM3 cells, and the effects of N-cad downregulation on cell aggregation, migration, and invasion were then analyzed. Furthermore, the correlation between N-cad expression and the surgical outcomes of a cohort of HCC patients was analyzed. Results: In liver tissues, N-cad was strongly expressed on cell–cell boundaries, whereas various reduced-expression patterns were observed in tumors. Of 64 HCC, 34 (53%) tumors showed reduced N-cad expression, compared with their adjacent liver tissues. The decreased expression of N-cad was significantly correlated with poorer tumor differentiation (P = 0.001) and vascular invasion (P = 0.003). N-cad knockdown in HCCLM3 cells resulted in decreased cell aggregation and increased cell migration and invasion. The decreased expression of N-cad in HCC was significantly associated with shorter postoperative disease-free survival (P = 0.039). Conclusions: N-cad expression is decreased in HCC, and the downregulation of N-cad is associated with the metastatic potential of HCC and poorer surgical prognosis.

Background and Aim: The conventional method of anatomical right hemihepatectomy (ARHH) requires hilus dissection. We report a method without hilus dissection to minimize intraoperative bleeding. Methods: We retrospectively evaluated data of 107 patients who received ARHH involving ligation of corresponding inflow and outflow vessels (LCIOV) without hilus dissection between January 2000 and October 2008. Results were compared to those of patients who underwent non-anatomical right hemihepatectomies (NARHH). Results: The two groups had similar gender and age (both, P > 0.05). The LCIOV group had a higher percentage of patients without intrahepatic metastases (94.6% vs 80.3%, P = 0.003). Hepatocellular carcinoma (HCC) lesion size (9.3 vs 10.2, P = 0.023), durations of inferior vena cava occlusion (4 vs 4.7, P

Background/aims Locoregional chemotherapy continues to be the mainstay for the treatment of unresectable hepatocellular carcinoma (HCC). One of the principal obstacles implicated in its unsuccessful therapy is multidrug resistance (MDR). Former studies have identified the multidrug-resistant nature and possible mechanisms of hepatoma cells both in vitro and in vivo. This work aimed to develop an effective strategy for the treatment of HCC with MDR. Methods The treatment was exploited to inhibit the MDR cells by co-administration of the recombinant mutant human tumour necrosis factor-alpha (rmhTNF-alpha), a sublethal dose of chemicals [adriamycin (ADM), mitomycin and 5-FU] and hydroxyapatite nanoparticles (nHAPs). Real-time quantitative reverse transcriptase-polymerase chain reaction and electrochemiluminescence Western blot were used to detect the expression of several related genes. Results The chemicals acted synergistically with rmhTNF-alpha and nHAP in suppressing the growth of hepatoma cells and inducing apoptosis of the cells, with the MDR phenotype reversed, as measured by intracellular ADM retention. Analysis of mRNA and protein revealed that rmhTNF-alpha inhibited the gene expression of XIAP, survivin, Ki67, PCNA, MDR1 and BCRP to some extent. Moreover, the inhibitory effects mentioned above could be as good or better than when nHAP is incorporated into the regimens. Conclusions rmhTNF-alpha was not only able to restore the chemotherapeutic sensitivity to HepG2/ADM, its xenograft model and clinical samples but also further inhibited the growth of these tumours by a combination of nHAP. These results strongly suggested that chemicals in combination with rmhTNF-alpha and nHAP may be beneficial for the local treatment of advanced HCC.

The concentrations of mercury (Hg), cadmium (Cd) and lead (Pb) at various exposure periods were determined in the gill, kidney, liver and muscle of common carp (Cyprinus carpio L.) co-exposed to 1.0 µg ml−1 each of Cd2+, Hg2+ and Pb2+ for up to 10 days. Metallothionein fractions (MTs) in these organs were characterized using the hyphenated technique of size-exclusion chromatography (SEC) and inductively coupled plasma mass spectrometry (ICP-MS). After 10 days of exposure, maximum toxic metal concentrations of Hg, Cd and Pb were 10.7 (gill), 0.145 (kidney) and 0.112 µg g−1dryweight (gill), respectively. The pattern of accumulation of Hg and Pb was in the order gill > kidney > liver > muscle. In the case of Cd, accumulation was in the order kidney > gill > liver > muscle. Cd and Hg binding MTs were significantly induced in the gill, kidney and liver of all the exposure groups in comparison with the control group (p < 0.05), and the amounts of them increased with the longer exposure time. Despite the higher intracellular Hg concentration and the stronger HgSH binding affinity, the amount of Cd-binding MTs was much higher than that of Hg-binding MTs. The results indicate that MT synthesis in these organs was clearly metal-specific. MTs in gill may be used as a bio-marker to detect the metal pollution caused by Hg and Cd. Zinc and copper binding MTs in the organs of the exposed fish were also increased. This may be due to the MTs' important role in the homeostatic regulation of essential metals and their protective role against the acute toxicity of non-essential metals. Even though there was considerable accumulation of lead in the organs of the exposed fish, Pb-binding MT synthesis was non-significant. Copyright © 2006 John Wiley & Sons, Ltd.

The influence of ball-milling methods on microstructure and mechanical properties of silicon nitride (Si3N4) ceramics produced by pressureless sintering for a sintering additive from MgO–Al2O3–SiO2 system was investigated. For planetary high-energy ball milling, the mechanical properties of Si3N4 ceramics were evidently improved and a homogeneous microstructure developed. In contrast, some exaggerated elongated grains were developed due to the local enrichment of sintering additives in the specimen prepared by general ball milling. For Si3N4 ceramics produced by planetary ball milling, flexure strength of 1.06 GPa, Vickers hardness of 14.2 GPa, and fracture toughness of 6.6 MPa·m0.5 were achieved. The differences in the mechanical properties of Si3N4 ceramics produced by different processing seem to arise mainly from the changes in microstructural homogenization and sinterability. The planetary high-energy ball-milling process provides a good route to mix starting powders for developing ceramics with uniform microstructure and promising mechanical properties.

Mercury, a highly toxic metal found widely throughout the environment, is a potent inducer of metallothionein (MT) expression. The role of MTs in the detoxification of mercury after its oral intake in mammals is studied. After feeding rats with mercuric chloride by gastric gavage, the distribution of heavy metals in rat tissues was investigated by inductively coupled plasma mass spectrometry (ICP-MS). Extensive accumulation of mercury, copper and zinc in kidney and liver is observed. A homemade preparative size-exclusion chromatography (SEC) column (30 cm × 1.9 cm) packed with Sephadex G-75 (40–120 µm particle size) gel (Pharmacia) was used for the purification of MT fractions in rat tissues. Preliminary results from SEC indicate that the mercury-binding MT levels in liver were much lower than in kidney. The MT fractions were collected, desalted, and then separated by reversed-phase high-performance liquid chromatography (HPLC) with UV–Vis spectrometry, ICP-MS and electrospray ionization MS detection. One major and several minor peaks were observed in the HPLC chromatograms of the MT fraction for the kidney sample. UV absorption spectra indicate that MTs were found to bind with mercury. There were no significant mercury-binding MTs detected in the liver sample using UV detection. ICP-MS detection showed that mercury-binding MTs in kidney contained large amounts of mercury and copper but little zinc. Further characterization with ESI-MS showed that the major peak found in kidney contained Hg6Cu, Hg5Cu2-MT-2c and Hg6-MT-2β, Hg6Cu-MT-1γ, Hg7-MT-2α. However, distinction between copper and zinc could not be made based on current mass spectrometric analysis because of instrumental resolution limitations. Copyright © 2005 John Wiley & Sons, Ltd.

Cinnabar, as one of the most widely used mineral drugs in traditional Chinese medicines, has been proven to have prominent curative effects in clinical use for more than 2000 years. But the safety and toxicity of the drug has been under constant debate in clinic usage. Metallothionein (MT) contains about 30% of cysteine in the molecule, and plays an important detoxification role against heavy metals. In this study, it was used as a biomarker to assess mercurial accumulation in rats fed orally with cinnabar. After feeding rats with cinnabar by gastric gavage at different dosages and at different times, the distribution of heavy metals (including mercury, copper and zinc) and MT was investigated among rat tissues, including liver, kidney, heart, brain, testis and blood. Metals and MT determinations were carried out using inductively coupled plasma mass spectrometry (ICP-MS) and a modified mercury saturation assay technique respectively. The results indicated that mercury was easily accumulated in the tissues of rats exposed to cinnabar, especially in kidney. For example: at a feeding dosage of 5 g kg−1 (bw) for 4 weeks, the mercury concentrations in kidney were 13, 8.7, 21.6 and 26 times those in liver, testis, brain and heart respectively; and at 2.5 g kg−1 (bw) for 2 weeks, the mercury concentrations in kidney were 21, 2.1, 3 and 21 times those in liver, testis, brain and heart respectively. In addition, mercury in kidney and liver of all cinnabar groups was significantly higher than that of the control group (P < 0.01). A high positive correlation observed between MT concentrations and mercury levels in both liver and kidney (R2 = 0.9299, P < 0.02 for liver; R2 = 0.9923, P < 0.0008 for kidney) indicated that MT could be used as a biomarker for mercury in tissues. Copyright © 2004 John Wiley & Sons, Ltd.

Based on previous studies demonstrating increased RAS activity in human astrocytomas, we developed a transgenic mouse model (B8) that targets an activated RAS molecule to astrocytes. Within 3 to 4 months after birth, these mice develop high-grade astrocytomas that are histologically identical to human astrocytomas. To characterize genetic events associated with B8 mouse astrocytoma formation, we employed comparative gene expression profiling of wild-type cultured mouse astrocytes, non-neoplastic B8 astrocytes, B8 astrocytoma cultures, and two other astrocytoma cultures from independently derived RAS transgenic mouse lines. We identified several classes of gene expression changes, including those associated with the non-neoplastic state in the B8 transgenic mouse, those associated with astrocytoma formation, and those specifically associated with only one of the three independently derived transgenic mouse astrocytomas. Differential expression of several unique genes was confirmed at the protein level in both the RAS transgenic mouse astrocytomas and two human glioblastoma multiforme cell lines. Furthermore, reexpression of one of these downregulated astrocytoma-associated proteins, GAP43, resulted in C6 glioma cell growth suppression. The use of this transgenic mouse model to identify novel genetic changes that might underlie the pathogenesis of human high-grade astrocytomas provides a unique opportunity to discover future targets for brain tumor therapy.

During the annual life cycle of the bumble bee Bombus terrestris (L.) colony, there is a stage characterized by worker reproduction in the presence of the queen. It has been proposed that this is a result of a decrease in queen inhibition. This hypothesis was examined by studying the effects of queens taken from colonies at different stages of development on several aspects of worker physiology and behaviour: rates of Juvenile Hormone (JH) release in vitro, ovary development, and behaviour associated with reproduction. After optimizing and validating the radiochemical assay for JH release for bumble bee workers, we found that queenless workers had significantly more developed ovaries and higher rates of release of JH than did queenright workers, confirming and extending previous findings that suggest that bumblebee ovarian development is under JH control. Mated queens, separated from their colony and brood, can have the same inhibitory effect on the reproductive development of callow workers. In contrast, workers confined with virgin queens or in queenless groups demonstrated a significantly higher rate of release of JH, overt aggression and threatening behaviours. However, there were no differences in rates of release of JH between workers confined in groups in the laboratory with queens taken from colonies either before or after the onset of worker reproduction. Furthermore, overt aggression and threatening behaviours were similar and low in both types of groups. These results gave no support to the hypothesis that a decrease in queen inhibition is associated with the onset of worker reproduction. We also show that young workers reared in colonies either before or after worker reproduction occurs, or in queenless colonies, all demonstrated similar, low rates of release of JH. These results suggest that older workers may inhibit the corpora allata of younger workers in queenless colonies.