Investigation on exceptional fuel CRUD samples by using radioactivity ratios of cobalt isotopes

Elemental analysis and radioactivity measurements were carried out for fuel CRUD samples obtained from a nuclear power plant. Comparisons were made for the relationship between (58)Co radioactivity and Ni content and for the radioactivity ratios of (58)Co to (60)Co of the samples. We found a peculiar radioactivity relationship from one of the samples and were able to further evaluate this based on its unique fuel exchange history. This analysis can be useful to enhance the data credibility of CRUD samples.

Maternal plasma cell-free fetal and maternal DNA at 11-13 weeks' gestation: relation to fetal and maternal characteristics and pregnancy outcomes

OBJECTIVE

To examine the possible relationship between maternal and fetal characteristics and pregnancy outcomes on fetal and maternal cell-free (cf) DNA in maternal plasma at 11-13 weeks' gestation.

METHODS

cfDNA was extracted from maternal plasma of 1,949 singleton pregnancies and chromosome-selective sequencing was used to determine the proportion of cfDNA and total cfDNA counts which was of fetal and maternal origin. Multivariate regression analysis was used to determine whether specific maternal and fetal characteristics and pregnancy complications, such as preeclampsia (PE), early spontaneous preterm birth (SPB) and delivery of small for gestational age (SGA) neonates, were significant predictors of fetal and maternal cfDNA in maternal plasma.

RESULTS

The fetal and maternal cfDNA plasma concentration increased with serum pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin level, was higher in women of Afro-Caribbean and East-Asian racial origin than in Caucasians, and lower in smokers, but it was not significantly altered in pregnancies complicated by PE, SPB or SGA. The fetal cfDNA level was inversely related to maternal weight and uterine artery pulsatility index, and maternal cfDNA increased with maternal weight.

CONCLUSIONS

The fetal and maternal cfDNA level in maternal plasma is affected by maternal and fetal characteristics, but it is not altered in pregnancy complications.

Trisomy 13 detection in the first trimester of pregnancy using a chromosome-selective cell-free DNA analysis method

OBJECTIVE

To assess the performance of chromosome-selective sequencing of maternal plasma cell-free DNA (cfDNA) in non-invasive prenatal testing for trisomy 13.

METHODS

Two-phase case-control study on a single plasma sample per case. The first phase was used to optimize the trisomy 13 algorithm, which was then applied to a second dataset to determine the risk score for trisomy 13 by laboratory personnel who were blinded to the fetal karyotype.

RESULTS

In the first phase, trisomy 13 risk scores were given for 11 cases of trisomy 13 and 145 euploid cases at 11-13 weeks' gestation. The test identified seven (63.6%) cases of trisomy 13 with no false positives. The trisomy 13 algorithm was subsequently modified and the trisomy 13 risk score was > 99% in all 11 cases of trisomy 13 and < 0.01% in all 145 euploid cases. In the second phase, the new algorithm was used to generate trisomy 13 risk scores for 10 cases of trisomy 13 and 1939 euploid cases. The trisomy 13 risk scores were > 99% in eight (80.0% (95% confidence interval (CI), 49.0-94.3%)) cases of trisomy 13. In the 1939 euploid cases the risk score for trisomy 13 was < 0.01% in 1937 (99.9%), 0.79% in one, and > 99% in one. Therefore, at the predefined risk cut-off of 1% for classifying a sample as high or low risk, the false-positive rate (FPR) was 0.05% (95% CI, 0.0-0.3%).

CONCLUSIONS

Chromosome-selective sequencing of cfDNA can detect the majority of cases of trisomy 13 at an FPR of less than 0.1%.

Loss of E-cadherin in multidrug resistant breast cancer cell line MCF-7/Adr: possible implication in the enhanced invasive ability

BACKGROUND

Recently, many observations have drawn researchers' attention to study drug resistance and invasion/metastasis as a single entity. However, little evidence is available about the relationship between the multiple drug resistance (MDR) and invasion so far.

AIM

To study the relationship between the multiple drug resistance and invasive-metastatic phenotypes in cancer cells.

MATERIALS AND METHODS

In this study, we compared the biological alterations of drug-resistant cells with their parental control and demonstrated that the drug-resistant cells have acquired enhanced invasive ability in addition to their acquired MDR phenotype.

RESULTS

Motility and invasiveness assays revealed that MCF-7 / Adr had an invasive phenotype. Light and electron microscopy showed loss of cell-cell clustering after trypsinization, loss of tight junctions and desmosomes, ultrastructural changes to the actin network and nucleus, loss of epithelial characters, and increase in filopodia in the drug resistant cell line. A major component of cell-cell junctions, E-cadherin, was shown to be expressed on the protein and RNA levels in MCF-7 but not MDF-7 / Adr cells. More protrusions (pseudopodia) on the cell surface were found in MCF-7 / Adr cells, which enable the cells to migrate and invade / metastasize. Examination of ultrastructural morphology revealed that great changes occurred in drug resistant cancer cells including absence of tight junctions/desmosomes, and dislocation of cytoskeleton microfilaments. Since the cadherin / catenin complexes are further associated with the major cytoskeleton components at cell-cell junctions, we measured E-cadherin expression in drug-resistant cells. Both Western blot and immunocytochemical staining demonstrated the loss of E-cadherin expression in MCF-7 / Adr cells. Further, RNA in situ hybridization results confirmed that loss of E-cadherin expression occurred at the transcriptional level.

CONCLUSIONS

The drug-resistant MCF-7/Adr cells were found to be more invasive/metastatic than their parental control, possibly related to the loss of E-cadherin expression.

Screening of plant extracts for human tyrosinase inhibiting effects

Screening for tyrosinase (TYR) inhibitors potentially useful for control of skin pigmentation has been hampered by the limited availability of human TYR. To overcome this hurdle, we have established human embryonic kidney (HEK293)-TYR cells that constitutively express human TYR. In the current study, we assayed human TYR inhibition activities of 50 plant extracts using the lysates of transformed HEK293-TYR cells. The strongest inhibition of human TYR was shown by the extract of Vaccinium bracteatum Thunberg, followed by the extract of Morus bombycis Koidzumi. The former extract did not inhibit mushroom TYR activity whereas significant inhibition was observed with the latter extract, demonstrating the importance of using human TYR in the screening for human TYR inhibitors. Upon liquid-liquid partitioning of the extract from V. bracteatum, the active constituents were enriched in the ethyl acetate fraction, and the subsequent preparatory thin-layer chromatography identified p-coumaric acid (PCA) as the main active constituent. The hypo-pigmentation of PCA was verified in the MelanoDerm™ Skin Model. This study demonstrates that transformed HEK293-TYR cells could expedite the discovery of human TYR-specific inhibitors from natural sources which might be useful in the control of skin pigmentation.

Spectroscopic studies on U(VI)-salicylate complex formation with multiple equilibria

This study investigates multiple equilibria related to the formation of the U(VI)-salicylate complex in a pH range of 3.0–5.5 using UV-Vis absorption and fluorescence measurement techniques. The absorbance changes at the characteristic charge-transfer bands of the complex were monitored, and the results indicated the presence of multiple equilibria and the formation of both 1:1 and 1:2 (U(VI):salicylate) complexes possessing bi-dentate chelate structures. The determined step-wise formation constants (log K 1:1 and log K 1:2) are as follows: 12.5 ± 0.1 and 11.4 ± 0.2 for salicylate, 11.2 ± 0.1 and 10.1 ± 0.2 for 5-sulfosalicylate, and 12.4 ± 0.1 and 11.4 ± 0.1 for 2,6-dihydroxybenzoate, respectively. The molar absorptivities of the complexes are also provided. Furthermore, time-resolved laser-induced luminescence spectra of U(VI) species demonstrate the presence of both a dynamic and static quenching process upon the addition of a salicylate ligand. Particularly for the luminescent hydroxouranyl species, a strong static quenching effect is observed. The results suggest that both the UO2(HSal)+ and the U(VI)–Sal chelate complexes serve as ground-state complexes that induce static quenching. The Stern–Volmer parameters were derived based on the measured luminescent intensity and lifetime data. The static quenching constants (log K S) obtained are 3.3 ± 0.1, 4.9 ± 0.1, and 4.4 ± 0.1 for UO2 2+, (UO2)2(OH)2 2+ and (UO2)3(OH)5 +, respectively.

The anti-apoptotic function of human αA-crystallin is directly related to its chaperone activity

αA-crystallin is a molecular chaperone and an antiapoptotic protein. This study investigated the mechanism of inhibition of apoptosis by human αA-crystallin and determined if the chaperone activity of αA-crystallin is required for the antiapoptotic function. αA-crystallin inhibited chemical-induced apoptosis in Chinese hamster ovary (CHO) cells and HeLa cells by inhibiting activation of caspase-3 and -9. In CHO cells, it inhibited apoptosis induced by the overexpression of human proapoptotic proteins, Bim and Bax. αA-crystallin inhibited doxorubicin-mediated activation of human procaspase-3 in CHO cells and it activated the PI3K/Akt cell survival pathway by promoting the phosphorylation of PDK1, Akt and phosphatase tensin homologue in HeLa cells. The phosphoinositide 3 kinase (PI3K) activity was increased by αA-crystallin overexpression but the protein content was unaltered. Downregulation of PI3K by the expression of a dominant-negative mutant or inhibition by LY294002 abrogated the ability of αA-crystallin to phosphorylate Akt. These antiapoptotic functions of αA-crystallin were enhanced in a mutant protein (R21A) that shows increased chaperone activity than the wild-type (Wt) protein. Interestingly, a mutant protein (R49A) that shows decreased chaperone activity was far weaker than the Wt protein in its antiapoptotic functions. Together, our study results show that αA-crystallin inhibits apoptosis by enhancing PI3K activity and inactivating phosphatase tensin homologue and that the antiapoptotic function is directly related to its chaperone activity.

Sequencing of Lp-PLA2-encoding PLA2G7 gene in 2000 Europeans reveals several rare loss-of-function mutations

Elevated plasma levels of lipoprotein-associated phospholipase A₂ (Lp-PLA2) activity have been shown to be associated with increased risk of coronary heart disease and an inhibitor of this enzyme is under development for the treatment of that condition. A Val279Phe null allele in this gene, that may influence patient eligibility for treatment, is relatively common in East Asians but has not been observed in Europeans. We investigated the existence and functional effects of low frequency alleles in a Western European population by re-sequencing the exons of PLA2G7 in 2000 samples. In all, 19 non-synonymous single-nucleotide polymorphisms (nsSNPs) were found, 14 in fewer than four subjects (minor allele frequency <0.1%). Lp-PLA2 activity was significantly lower in rare nsSNP carriers compared with non-carriers (167.8±63.2 vs 204.6±41.8, P=0.01) and seven variants had enzyme activities consistent with a null allele. The cumulative frequency of these null alleles was 0.25%, so <1 in 10 000 Europeans would be expected to be homozygous, and thus not potentially benefit from treatment with an Lp-PLA2 inhibitor.

Efficacy of immediate post-TUR mitomycin-C (MMC) instillation in high-risk non-muscle-invasive bladder cancer treated with bacillus Calmette-Guerin (BCG)

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Background: To evaluate the efficacy of immediate post-TUR MMC instillation in high risk non-muscle-invasive bladder cancer treated with BCG.

Methods: From January 2000 to December 2007, 162 high-risk non-muscle-invasive bladder cancer patients underwent TUR and BCG instillation at our institution. Among them 76 patients received additional immediate post-TUR MMC instillation (Group A), and remaining 86 patients underwent TUR and BCG instillation only (Group B). 60mg of MMC was mixed with 50ml of normal saline and was instilled in bladder within 2 hours after TUR. Tice strain BCG 12.5mg was used with 6-week induction course followed by 3-week maintenance every 3 months. The recurrence rate, time to recurrence, and stage and grade at recurrence were investigated. The mean follow-up was 33.4 months.

Results: There were no significant differences in the characteristics of both groups, including age, sex, stage, and grade. Group A showed significantly lower recurrence rate than Group B (26.3% vs 48.8%, p=0.003). Group A showed somewhat longer time to recurrence but it was not statistically different (24.9 months vs 21.8 months, p=0.293). The change in stage and grade at recurrence were not different between 2 groups ( Table ). The 5-year recurrence free survival rate was significantly higher in Group A (72% vs 42%, p=0.003).

Conclusions: The immediate post-TUR MMC instillation significantly reduced recurrence in high risk non-muscle-invasive bladder cancer patients treated by BCG. But it did not influenced the stage and grade at recurrence.

[Table: see text]

No significant financial relationships to disclose.