The kinetics of photocatalytic degradation of aliphatic carboxylic acids in an UV/TiO2 suspension system

Kinetic studies on the photocatalytic degradation of aliphatic carboxylic acids were carried out in a slurry photoreactor with in-situ monitoring, employing artificial UV light as the source of energy and nano-TiO2 powder as the catalyst. The influences on the photocatalytic degradation such as the initial concentration of reactant (C0), catalyst dosage (CTiO2), UV intensity (Ia) and pH value have been investigated. Good agreement has been obtained between the value calculated by Langmuir-Freundlich-Hinshelwood (L-F-H) model and experimental data, with coefficient of multiple determination (R2) varying from 0.880 to 0.999. The L-F-H model has been proven to be feasible in describing the kinetic characteristic of the photocatalytic degradation of aliphatic carboxylic acids. Moreover, the apparent reaction rate constant (k) of the photocatalytic degradation of dicarboxylic acids is higher than that of monocarboxylic acids with the same carbon atoms. This shows that the photocatalytic degradation rate is favoured by different chemical structure.

Echinoside A, a new marine-derived anticancer saponin, targets topoisomerase2alpha by unique interference with its DNA binding and catalytic cycle

BACKGROUND

Echinoside A was isolated from sea cucumber. This study demonstrates its anticancer effects and its mechanisms of action.

MATERIALS AND METHODS

Anticancer effects of echinoside A were evaluated in vitro and in vivo. TUNEL and DNA fragmentation assays were applied to examine its ability to induce apoptosis. A series of biochemical assays were applied to investigate the inhibition of echinoside A on topoisomerase2alpha (Top2alpha). Molecular docking analyses were used to demonstrate the direct interaction between echinoside A and Top2alpha.

RESULTS

Echinoside A inhibited the growth of tumors in mouse models and human prostate carcinoma xenografts in nude mouse models. Echinoside A shows the unique characteristics of inhibiting the noncovalent binding of Top2alpha to DNA by competing with DNA for the DNA-binding domain of the enzyme and of interfering predominantly with the Top2alpha-mediated prestrand passage cleavage/religation equilibrium over with the poststrand passage one. These features distinguish echinoside A from other known Top2alpha inhibitors. As a result, echinoside A induced DNA double-strand breaks in a Top2-dependent manner.

CONCLUSION

Echinoside A targets Top2alpha by unique interference with the binding of Top2 to DNA and by imparing the Top2-mediated DNA cleavage and religation, exerting potent in vitro and in vivo antitumor activities.

Study on genes with altered expression in alpha-amanitin poisoned mice and evaluation on antagonistic effects of traditional Chinese medicines against toxicity of alpha-amanitin

The forward and reverse cDNA subtractive libraries before and after the toxic effect of alpha-amanitin were constructed by suppression subtractive hybridization and randomly selected clones from each subtractive library were screened by PCR and dot blot hybridization. A total of 85 genes with altered expression were finally identified, with 41 genes from the forward library and 44 from the reverse library. Subsequently, the antagonistic effects of candidate traditional Chinese medicines were evaluated based on the genetic transcription levels of the genes with significant altered expression, including Catnbeta, Flt3-L, IL-7r and Rpo2-4. The results indicated that Silybum marianum (L.) Gaert and Ganoderma lucidum had significant down-regulated effects on the transcription level of Catnbeta that was up-regulated by alpha-amanitin, and the two herbs also up-regulated the transcription levels of Flt3-L and Rpo2-4. Silybum marianum (L.) had significant up-regulated effects on the IL-7r that was down-regulated by alpha-amanitin. These preliminary studies suggested that Silybum marianum (L.) and Ganoderma lucidum were effective antagonists against the toxicity of alpha-amanitin.

Behaviors of microtubules (MTs) driven by biological motors (dynein c) at collisions against micro-fabricated tracks and mts for potential nano-bio-machines

In vitro motility assays, where protein motors (attached to a surface) move protein filaments, have been used for investigating protein motors' functions. In recent decades, these assays are extended to explore potential applications of motor proteins as biological motors in nano-bio-machine development. Recent attempts include fabricating micrometer-scale tracks on the surface to confine and guide the flow of bio-filaments as a power transfer medium driven by the motor proteins. Understanding the interaction between bio-filaments and fabricated tracks as well as the mutual interaction between bio-filaments is of importance to the design of potential nano-bio-machines. In this study, we investigate the behaviors of a microtubule driven by axonemal dynein at the collision against another microtubule and micro-fabricated walls, respectively. Based on experimental observations, we propose a model to study possible mechanisms for the microtubule-microtubule and microtubule-wall interactions, which involve bumping force, bending moment and torque generation.

Increased frequencies of T helper type 17 cells in the peripheral blood of patients with acute myeloid leukaemia

T helper type 17 (Th17) cells, which represent a novel subset of CD4(+) T cells, play an active role in inflammatory and autoimmune diseases. Recent studies have also suggested that they have an impact on solid tumours. However, the nature of Th17 cells in haematological malignancies remains unknown. In this study, we investigated Th17 cell frequency and secretion of related cytokines in patients with acute myeloid leukaemia (AML). First, we found that Th17 cell frequencies were increased significantly in peripheral blood samples from untreated patients with AML, compared with those from healthy volunteers. Moreover, increased interleukin (IL)-17 concentrations accompanied the increased Th17 cell frequencies in these patients. These results suggest that Th17 cells may play a role in the pathogenesis of AML. Secondly, we found that the increased Th17 cell frequencies were reduced when patients achieved complete remission after chemotherapy, suggesting that measurement of Th17 cell frequencies may have clinical value in the evaluation of therapeutic effect. In addition, we found that IL-6 and transforming growth factor (TGF)-beta1 concentrations increased in the untreated patients and that IL-6 concentrations showed a positive correlation with the frequencies of Th17 cells, suggesting that IL-6 may play an important role in Th17 cell differentiation in patients with AML.

Anti-phospholipid antibodies increase non-apoptotic trophoblast shedding: a contribution to the pathogenesis of pre-eclampsia in affected women?

Pre-eclampsia is associated with trophoblast shedding-deportation and endothelial cell dysfunction. Anti-phospholipid autoantibodies increase a women's risk factor of developing pre-eclampsia. In this study we examined the hypothesis that anti-phospholipid antibodies alter the number and nature of trophoblasts shed from the placenta, and that phagocytosis of these altered trophoblasts results in endothelial cell activation. To investigate this we used a placental explant model in which explants were treated with anti-phospholipid antibodies. This treatment resulted in a doubling of the amount of trophoblast shed from the explants. Furthermore, the trophoblasts shed from anti-phospholipid antibody-treated explants were more readily phagocytosed by endothelial cells and subsequently caused the activation of the endothelial cells, as indicated by increased expression of endothelial cell surface ICAM-1 determined by cell-based ELISA, and monocyte adhesion as determined by flow cytometry. Confocal microscopy analysis of trophoblasts shed from anti-phospholipid antibody-treated or control explants demonstrated that anti-phospholipid antibodies, but not control antibodies, were internalised within trophoblasts shed from the explants, and this was accompanied by a reduction in the activity of caspases 3 and 7 in the shed trophoblasts as indicated by FLICA. These results suggest that anti-phospholipid antibodies are selectively transported into trophoblasts where they affect the regulation of the cell cycle leading to excess and aberrant death (necrotic or aponecrotic) and shedding of trophoblasts. If reflected in vivo this might explain, at least in part, how anti-phospholipid antibodies contribute to the pathogenesis of pre-eclampsia.

Distribution of vasoactive intestinal peptide and substance P messenger ribonucleic acid in intestinal nerve of Remak of chicken

The intestinal nerve of Remak (INR) is unique to birds. The exact distributions and secretions of the peptide transmitters in the INR that innervate the intestine, and the patterns of their projections to the nerve plexus of the intestinal wall, are still unclear. In the present study, the distributions of chicken vasoactive intestinal peptide (VIP) mRNA and substance P (SP) mRNA in the chicken INR were demonstrated by means of in situ hybridization histochemistry, using sense and antisense digoxigenin-labeled RNA probes. The in situ hybridization histochemistry results suggested that VIP mRNA-positive neurons were mainly distributed in ganglions, whereas some of the INR fibers were weakly positive. The proportion of VIP mRNA-positive cells among total neurons was 75% in the juxta-jejunoileum portion and 87% in the juxta-rectal portion of the INR. Most SP mRNA-positive cells were sporadically distributed in layers or small groups within the ganglions, as well as in nerve trunks between ganglions. Moreover, the proportion of positive cells among total neurons was 83% in the juxta-jejunoileum portion and 98% in the juxta-rectal portion of the INR, which suggests that both VIP and SP mRNA are coexpressed in the chicken INR. Our results provide an approach to further study of the locations of VIP and SP in nerve tissue.

Cytoskeleton disorganization during apoptosis induced by curcumin in A549 lung adenocarcinoma cells

Several studies have shown that curcumin can induce apoptosis and inhibit growth in human A549 lung adenocarcinoma cells. However, the mechanism is not completely understood yet. In the present study, we investigated the in vitro effect of curcumin on cell viability, apoptosis and disorganization of the actin cytoskeleton in A549 cells. Our results showed that curcumin significantly inhibited the viability of A549 cells in a dose- and time-dependent manner by induced apoptosis. The apoptotic process was associated with a disorganization of the architecture of actin microfilaments and a decrease in the levels of F-actin. DMSO-treated control cells exhibited a well-defined F-actin network that was mainly organized into stress fibers. The actin fibers in cells treated with curcumin or the positive control drug cytochalasin B were disorganized, disassembled, or disrupted, however, the disorganization of actin fibers and apoptosis could be prevented by phalloidin, an F-actin stabilizing compound. Thus, these results demonstrated that actin filament disorganization might play a central role in the curcumin-induced apoptosis of A549 cells.

Phase IIb trial of fluorouracil, leucovorin, oxaliplatin, and paclitaxel (POF) compared with fluorouracil, feucovorin, and irinotecan (IF) as first-line treatment for advanced gastric cancer (AGC)

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Background: Primary results of POF as 1st and 2nd line treatment for AGC have been presented at ASCO 2007 and 2008. We report here data on the feasibility and the toxicity of POF versus IF(Dank, et al, ASCO 2005) in 1st line treatment of AGC. Methods: Patients with previously untreated, advanced, unresectable, and histologically confirmed adenocarcinoma of the gastric or gastroesophageal junction were randomly assigned to POF or IF regiment. Treatment was continued until disease progressed, unacceptable toxicity, or patient choice. Results: 25 patients were entered in this study between March 2007 and July 2007: 13 in the POF group and 12 in the IF group. The median patient age was 55 years (range, 36 to 67 years), 18 were males and 7 were females. No complete response was observed. The response rate was 62.5% (POF) and 33.3% (IF) respectively. At a median follow-up of 285 days, 7(POF) versus 6(IF) patients were still alive. Hematological toxicity was the most frequent toxicity in both groups. Grade 3 to 4 neutropenia were 38.5% (POF) versus 8.3% (IF). Diarrhea was found 0% and 8.3% in POF and IF group respectively. No grade 3 peripheral neurotoxicity was observed. Conclusions: Compared with IF regiment, POF could also be used as first-line treatment for AGC with acceptable safety profile, good efficacy, and more encouraging results.

No significant financial relationships to disclose.

A comparison of complete mitochondrial genomes of silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis: implications for their taxonomic relationship and phylogeny

Based upon morphological characters, Silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis (or Aristichthys nobilis) have been classified into either the same genus or two distinct genera. Consequently, the taxonomic relationship of the two species at the generic level remains equivocal. This issue is addressed by sequencing complete mitochondrial genomes of H. molitrix and H. nobilis, comparing their mitogenome organization, structure and sequence similarity, and conducting a comprehensive phylogenetic analysis of cyprinid species. As with other cyprinid fishes, the mitogenomes of the two species were structurally conserved, containing 37 genes including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA (tRNAs) genes and a putative control region (D-loop). Sequence similarity between the two mitogenomes varied in different genes or regions, being highest in the tRNA genes (98.8%), lowest in the control region (89.4%) and intermediate in the protein-coding genes (94.2%). Analyses of the sequence comparison and phylogeny using concatenated protein sequences support the view that the two species belong to the genus Hypophthalmichthys. Further studies using nuclear markers and involving more closely related species, and the systematic combination of traditional biology and molecular biology are needed in order to confirm this conclusion.

The impact of NOTCH1, FBW7 and PTEN mutations on prognosis and downstream signaling in pediatric T-cell acute lymphoblastic leukemia: a report from the Children's Oncology Group

We explored the impact of mutations in the NOTCH1, FBW7 and PTEN genes on prognosis and downstream signaling in a well-defined cohort of 47 patients with pediatric T-cell acute lymphoblastic leukemia (T-ALL). In T-ALL lymphoblasts, we identified high-frequency mutations in NOTCH1 (n=16), FBW7 (n=5) and PTEN (n=26). NOTCH1 mutations resulted in 1.3- to 3.3-fold increased transactivation of an HES1 reporter construct over wild-type NOTCH1; mutant FBW7 resulted in further augmentation of reporter gene activity. NOTCH1 and FBW7 mutations were accompanied by increased median transcripts for NOTCH1 target genes (HES1, DELTEX1 and cMYC). However, none of these mutations were associated with treatment outcome. Elevated HES1, DELTEX1 and cMYC transcripts were associated with significant increases in transcript levels of several chemotherapy relevant genes, including MDR1, ABCC5, reduced folate carrier, asparagine synthetase, thiopurine methyltransferase, BCL2 and dihydrofolate reductase. PTEN transcripts positively correlated with HES1 and cMYC transcript levels. Our results suggest that (1) multiple factors should be considered with attempting to identify molecular-based prognostic factors for pediatric T-ALL, and (2) depending on the NOTCH1 signaling status, modifications in the types or dosing of standard chemotherapy drugs for T-ALL, or combinations of agents capable of targeting NOTCH1, AKT and/or mTOR with standard chemotherapy agents may be warranted.

MR imaging findings of the uveal schwannoma

BACKGROUND AND PURPOSE

Uveal schwannoma is a rare benign neoplastic proliferation of pure Schwann cells. The purpose of this study was to describe MR imaging features of uveal schwannoma.

MATERIALS AND METHODS

MR images in 6 female patients with uveal schwannoma confirmed by pathologic examination were retrospectively reviewed. MR imaging was performed in all 6 patients, with postcontrast T1-weighted imaging (T1WI) completed in all 6 patients and dynamic contrast-enhanced MR imaging, in 5. MR imaging findings of the tumor were evaluated with emphasis on the location, size, shape, margin, signal intensity, and pattern of enhancement.

RESULTS

The lesions appeared as solitary well-defined ovoid masses in the ciliochoroidal region in 5 patients and in the choroid in 1. With respect to the vitreous body, uveal schwannoma was hyperintense on T1WI spin-echo (SE) images in all 6 patients. The tumors were hypointense to the vitreous body on fast SE (FSE) T2-weighted images (T2WI) in 4 patients and isointense in 1. However, with respect to the brain, uveal schwannoma demonstrated isointensity on T1WI SE images in all 6 patients, isointensity on FSE T2WI images in 5 patients, and hyperintensity on T2WI SE images in 1. On postcontrast T1WI images, 3 patients showed markedly heterogeneous enhancement, and 3 showed markedly homogeneous enhancement.

CONCLUSIONS

Uveal schwannoma should be included in the differential diagnosis when an oval isointense mass relative to brain is seen in the ciliochoroidal region.