Shape Dependence of Silver-Nanoparticle-Mediated Synthesis of Gold Nanoclusters with Small Molecules as Capping Ligands.

In this study, differently shaped silver nanoparticles used for the synthesis of gold nanoclusters with small capping ligands were demonstrated. Silver nanoparticles provide a reaction platform that plays dual roles in the formation of Au NCs. One is to reduce gold ions and the other is to attract capping ligands to the surface of nanoparticles. The binding of capping ligands to the AgNP surface creates a restricted space on the surface while gold ions are being reduced by the particles. Four different shapes of AgNPs were prepared and used to examine whether or not this approach is dependent on the morphology of AgNPs. Quasi-spherical AgNPs and silver nanoplates showed excellent results when they were used to synthesize Au NCs. Spherical AgNPs and triangular nanoplates exhibited limited synthesis of Au NCs. TEM images demonstrated that Au NCs were transiently assembled on the surface of silver nanoparticles in the method. The formation of Au NCs was observed on the whole surface of the QS-AgNPs if the synthesis of Au NCs was mediated by QS-AgNPs. In contrast, formation of Au NCs was only observed on the edges and corners of AgNPts if the synthesis of Au NCs was mediated by AgNPts. All of the synthesized Au NCs emitted bright red fluorescence under UV-box irradiation. The synthesized Au NCs displayed similar fluorescent properties, including quantum yields and excitation and emission wavelengths.

Physical Properties and the Reconstruction of Unstable Decahedral Silver Nanoparticles Synthesized Using Plasmon-Mediated Photochemical Process.

Plasmon-mediated shape transformation from quasi-spherical silver nanoparticles (AgNPs) to silver nanoprisms (AgNPrs) and decahedral silver nanoparticles (D-AgNPs) under irradiation of blue LEDs (λ = 456 ± 12 nm, 80 mW/cm2) was studied at temperatures ranging between 60, 40, 30, 20, 10, and 0 °C. It was found that reaction temperature affected transformation rates and influenced the morphology distribution of final products. The major products synthesized at temperatures between 60 °C and 0 °C were AgNPrs and D-AgNPs, respectively. The D-AgNPs synthesized at such low temperatures are unstable and become blunt when light irradiation is removed after the photochemical synthesis. These blunt nanoparticles with pentagonal multiple-twinned structures can be further used as the seeds to reconstruct complete D-AgNPs after irradiating blue LEDs at various bath temperatures. Our results showed that these rebuilt D-AgNPs are much more stable when at higher bath temperatures. Furthermore, the rebuilt D-AgNPs (edge lengths ~41 nm) can grow into larger D-AgNPs (edge lengths ~53 nm) after the irradiation of green LEDs. Surface-enhanced Raman spectra of CV in AgNP colloids showed that D-AgNP colloids have better SERS enhancements factors than AgNPrs.

Silver Nanoparticle-Mediated Synthesis of Fluorescent Thiolated Gold Nanoclusters.

A new strategy using silver nanoparticles (Ag NPs) to synthesize thiolated Au NCs is demonstrated. The quasi-spherical Ag NPs serve as a platform, functioning as a reducing agent for Au (III) and attracting capping ligands to the surface of the Ag NPs. Glutathione disulfide (GSSG) and dithiothreitol (DTT) were used as capping ligands to synthesize thiolated Au NCs (glutathione-Au NCs and DTT-Au NCs). The glutathione-Au NCs and DTT-Au NCs showed red color luminance with similar emission wavelengths (630 nm) at an excitation wavelength of 354 nm. The quantum yields of the glutathione-Au NCs and DTT-Au NCs were measured to be 7.3% and 7.0%, respectively. An electrophoretic mobility assay showed that the glutathione-Au NCs moved toward the anode, while the DTT-Au NCs were not mobile under the electric field, suggesting that the total net charge of the thiolated Au NCs is determined by the charges on the capping ligands. The detection of the KSV values, 26 M-1 and 0 M-1, respectively, revealed that glutathione-Au NCs are much more accessible to an aqueous environment than DTT-Au NCs.

TCH1036, a indeno[1,2-c]quinoline derivative, potentially inhibited the growth of human brain malignant glioma (GBM) 8401 cells via suppression of the expression of Suv39h1 and PARP.

A newly synthesized Indeno[1,2-c]quinoline derivative, which has previously been found to potentially trap DNA-topoisomerase cleavage complexes more effectively than camptothecin, could effectively inhibit the proliferation of a variety of cancers, such as breast cancer treated with TCH1030. In this study, we further explore the activity of the TCH1036, TCH1259 and TCH1030 compounds in suppressing the growth of human brain malignant glioma (GBM) 8401 cells, in addition to elucidating the related mechanisms. According to tests of cytotoxicity, the GBM cells were more sensitive to the inhibitory effects of the TCH1036 compound than to those of the other two compounds. Moreover, the accumulation of GBM cells in the sub-G1 and G2/M phases was clearly induced by the TCH1036 compound in a dose-dependent manner. A screening of the majority of histone-modifier enzymes indicated that the expression of Suv39h1 in the GBM cells was attenuated by treatment with each of the TCH compounds, an observation which was further confirmed by Western blotting. The increase in active-form caspase 3 in the GBM cells treated with TCH compounds caused a high degree of poly (ADP-ribose) polymerase (PARP) cleavage and also enhanced the high ratio of hypodiploid GBM cells in the sub-G1 phase. In molecular docking simulations, it was observed that the stable forms of the TCH compounds could successfully insert into the catalytic pocket of PARP, with the highest affinity being between PARP and the TCH1036 compound. These findings suggested that the TCH1036 compound would be a promising compound in the treatment of brain malignant glioma.

Positive cyclin T expression as a favorable prognostic factor in treating gastric gastrointestinal stromal tumors.

Positive transcriptional elongation factor b (P-TEFb) contains the catalytic subunit cyclin-dependent kinase 9 (Cdk9) and the regulatory subunit cyclin T. Cyclin T1 and Cdk9 are the key factors of the PTEFb pathways and are overexpressed in the human head and neck carcinoma cell line. However, there have been limited studies regarding the role of cyclin T1 and Cdk9 in gastric gastrointestinal stromal tumors (GISTs). The aim of the present study was to assess the association between cyclin T1 and Cdk9 and their clinical significance in gastric GISTs. A total of 30 gastric GIST patients who underwent either laparoscopic or laparotomic partial gastrectomy were enrolled in the study. The surgical tissue slides were stained with Cdk9 and cyclin T1 antibodies, and the immunohistochemistry scores and disease-free survival (DFS) were analyzed. Ten patients were cyclin T1-positive, and 20 were negative. All 11 patients with recurrent tumors or distant metastases were cyclin T1-negative patients. Old age, large tumor size, a high Ki67 IHC staining score, high mitotic count and negative cyclin T1 staining revealed a worse clinical outcome in univariate analysis. By contrast, the Cdk9 score was not associated with clinical parameters. The Kaplan-Meier survival curve illustrated that the DFS rate of the patients with negative cyclin T1 staining was significantly lower than that of the patients with positive cyclin T1 staining. Positive expression of cyclin T1 was a good prognostic factor in patients with gastric GISTs.

Increased cyclin T1 expression as a favorable prognostic factor in treating gastric adenocarcinoma.

The expression of cyclin A, B1, D1 and E in gastric adenocarcinoma is known to be associated with clinical outcome. However, few studies have investigated the role of cyclin T1 and cyclin-dependent kinase 9 (CDK9) in gastric adenocarcinoma. Therefore, this study assessed the clinical significance of cyclin T1 and CDK9 expression in gastric adenocarcinoma. A total of 39 gastric adenocarcinoma patients received either radical total or distal gastrectomy in this study. Surgical tissue slides were stained with CDK9 and cyclin T1 antibodies, and immunohistochemistry scores and disease-free survival (DFS) rates were analyzed. Among the 19 patients with tumor-recurrent or distant metastasis, 16 were recorded as exhibiting low expression of cyclin T1. The remaining three patients exhibited high expression of the antibody. The results of patients with a higher T stage, N stage and tumor grade were less favorable. For patients with adenocarcinoma, the percentage of tissue slides stained with cyclin T1 was significantly higher than for those with normal stomach epithelia. The DFS rates of patients with low expression of cyclin T1 were significantly associated with poorer DFS rates. In conclusion, high expression of cyclin T1 is a favorable prognostic factor in treating patients with stomach adenocarcinoma.

Impacts of size and shape of silver nanoparticles on Arabidopsis plant growth and gene expression.

Silver nanoparticles (AgNPs) are widely used as antibacterial nanomaterials; however, the environmental impacts of AgNPs remain uncertain. In this study, Arabidopsis physiological responses and gene expression were investigated after exposure to 3 different morphologies of AgNPs. The triangular (47 ± 7 nm) and spherical (8 ± 2 nm) AgNPs exhibited the lowest and highest degrees of antimicrobial activity, respectively. The AgNP-induced phenotypic alterations in Arabidopsis were correlated with nanoparticle morphology and size, in which the decahedral AgNPs (45 ± 5 nm) induced the highest degree of root growth promotion (RGP); however, the spherical AgNPs exhibited no RGP and induced the highest levels of anthocyanin accumulation in Arabidopsis seedlings. The decahedral and spherical AgNPs induced the lowest and highest levels of Cu/Zn superoxide dismutase (CSD2) accumulation, respectively. Moreover, 3 morphologies of AgNPs induced protein accumulations including cell-division-cycle kinase 2 (CDC2), protochlorophyllide oxidoreductase (POR), and fructose-1,6 bisphosphate aldolase (FBA). Regarding transcription, the AgNPs induced the gene expression of indoleacetic acid protein 8 (IAA8), 9-cis-epoxycarotenoid dioxygenase (NCED3), and dehydration-responsive RD22. Additional studies have shown that AgNPs antagonized the aminocyclopropane-1-carboxylic acid (ACC)-derived inhibition of root elongation in Arabidopsis seedlings, as well as reduced the expression of ACC synthase 7 (ACS7) and ACC oxidase 2 (ACO2), suggesting that AgNPs acted as inhibitors of ethylene (ET) perception and could interfere with ET biosynthesis. In conclusion, AgNPs induce ROS accumulation and root growth promotion in Arabidopsis. AgNPs activate Arabidopsis gene expression involved in cellular events, including cell proliferation, metabolism, and hormone signaling pathways.

Ogilvie syndrome: a potentially life-threatening phenotype of immobilization hypercalcemia.

Ogilvie syndrome, also known as acute colonic pseudo-obstruction, is characterized by the clinical presentation and imaging evidence of acute colonic obstruction in the absence of a mechanical cause. Several comorbidities and serious associated medical or surgical conditions have been described to be relevant to this syndrome. In general, a preferred initial management with favorable treatment outcomes is virtually to correct underlying disorders. Although disrupted electrolyte homeostasis may induce impaired colonic motility, hypercalcemia secondary to immobilization as a major culprit in this syndrome has rarely been studied. In this report, we profiled radiographic features, therapeutic strategies, and pathogenetic hypothesis of this clinical entity and highlighted the need for clinicians to maintain awareness of this distinct manifestation.

Effect of Temperature on the Growth of Silver Nanoparticles Using Plasmon-Mediated Method under the Irradiation of Green LEDs.

Plasmon-mediated shape conversion of spherical silver nanoparticles (NPs) to nanostructures with other shapes under the irradiation of green LEDs (520 ± 20 nm, 35 mw/cm²) at various temperatures (60, 40, 20, 10, 5, and 0 °C) was performed in this study. It was found that the bath temperature used in the reaction can influence the reaction rates, i.e., the times needed for the shape transformation process were 5, 11.5, 25, 45, 72, and 100 h at 60, 40, 20, 10, 5, and 0 °C, respectively. In addition, the bath temperature can also alter the morphologies of the final products. The major products are silver nanoplates at 60, 40 and 20 °C. However, they became decahedral silver NPs at 5 and 0 °C. The percentages of decahedral silver NPs synthesized at 60, 40, 20, 10, 5, and 0 °C are 0%, 1%, 5%, 45%, 73%, and 89%, respectively. Measuring the surface-enhanced Raman spectroscopy (SERS) spectra of the probe molecule R6G in the presence of KBr showed that both silver nanoplate colloids synthesized at 60 °C and decahedral silver NP colloids synthesized at 0 °C in the absence of PVP had good SERS activities.

The ICNARC model is predictive of hospital mortality in critically ill patients supported by acute dialysis.

AIMS: To compare prediction power between ICNARC model and RIFLE classification in postoperative patients receiving acute dialysis. MATERIAL AND METHOD: Between January 2002 and December 2008, 529 patients received acute dialysis during their ICU stay were enrolled. Patients' demographic, clinical and laboratory variables were analyzed as predictors of mortality. The RIFLE logistic regression and the ICNARC model on ICU admission were evaluated to predict the patient's hospital mortality. RESULTS: Hospital mortality for the study group was 29.3%. Between two score systems, the ICNARC model showed better mortality prediction in this patient group by using the area under the receiver operating characteristic curve (ICNARC 0.836, RIFLE 0.702, p < 0.05). Multiple logistic regression analysis indicated that age, surgery category, metastatic carcinoma, ventilator use, and previous history of hypertension were also affecting factors for hospital mortality. CONCLUSIONS: The RIFLE classification and the ICNARC model were both correlated with mortality in critically ill patient with acute dialysis. However, the ICNARC model was a better mortality predictor compared to the RIFLE classification.

Preparation of magnetic nanoparticles and their use for immobilization of C-terminally lysine-tagged Bacillus sp. TS-23 α-amylase.

The aim of this investigation was to synthesize the adipic acid-modified magnetic nanoparticles for the efficient immobilization of C-terminally lysine-tagged α-amylase (BACΔNC-Lys7) from thermophilic Bacillus sp. strain TS-23. The carboxylated magnetic nanoparticles were prepared by the simple co-precipitation of Fe³âº/Fe²âº in aqueous medium and then subsequently modified with adipic acid. Transmission electron microscopy micrographs showed that the carboxylated magnetic nanoparticles remained discrete and had no significant change in size after the binding of BACΔNC-Lys7. Free enzyme was active in the temperature range of 45-70 °C and had an optimum of 60 °C, whereas the thermal stability of BACΔNC-Lys7 was improved as a result of immobilization. The immobilized BACΔNC-Lys7 could be recycled 20 times without a significant loss of the amylase activity and had a better stability during storage with respect to free enzyme. Taken together, the magnetic nanoparticles coated with this functional moiety can be a versatile platform for the effective manipulation of various kinds of engineered proteins.

Biophysical studies of an NAD(P)(+)-dependent aldehyde dehydrogenase from Bacillus licheniformis.

Aldehyde dehydrogenase (ALDH) catalyzes the conversion of aldehydes to the corresponding acids by means of an NAD(P)(+)-dependent virtually irreversible reaction. In this investigation, the biophysical properties of a recombinant Bacillus licheniformis ALDH (BlALDH) were characterized in detail by analytical ultracentrifuge (AUC) and various spectroscopic techniques. The oligomeric state of BlALDH in solution was determined to be tetrameric by AUC. Far-UV circular dichroism analysis revealed that the secondary structures of BlALDH were not altered in the presence of acetone and ethanol, whereas SDS had a detrimental effect on the folding of the enzyme. Thermal unfolding of this enzyme was found to be highly irreversible. The native enzyme started to unfold beyond ~0.2 M guanidine hydrochloride (GdnHCl) and reached an unfolded intermediate, [GdnHCl](05, N-U), at 0.93 M. BlALDH was active at concentrations of urea below 2 M, but it experienced an irreversible unfolding under 8 M denaturant. Taken together, this study provides a foundation for the future structural investigation of BlALDH, a typical member of ALDH superfamily enzymes.

Promoter methylation in circadian genes of endometrial cancers detected by methylation-specific PCR.

Methylation of CpG dinucleotides in the promoter sequence of a gene can lead to deregulated and suppressed gene expression. In this study, we have developed procedures for methylation-specific polymerase chain reaction (MSP) and sequencing analysis to determine CpG methylation status of the promoter sequences of nine circadian genes in 35 endometrial cancers (EC) and paired noncancerous endometrial tissues. DNA methylation was found in the promoter sequences of PER1, PER2, and CRY1, but not of other six circadian genes in the ECs and normal tissues examined. Eleven of the 35 EC tissues showed CpG methylation in the promoter sequences of PER1, PER2, or CRY1. Of these 11 cases, 1 had promoter methylation in all the three genes, 1 in PER1 and PER2, 3 in PER1 and CRY1, and 6 in PER1, respectively. In comparison, promoter CpG methylation of PER1, PER2, or CRY1 was found in only 7 of 35 paired noncancerous tissues including 2 in PER1 and PER2, 2 in PER1, and 3 in CRY1. In summary, promoter methylation in the PER1, PER2, or CRY1 circadian genes was detected in about one-third of EC and one-fifth of noncancerous endometrial tissues of 35 paired specimens indicating possible disruption of the circadian clock in the development of EC.

SARS-CoV infection was from at least two origins in the Taiwan area.

OBJECTIVE: Severe acute respiratory syndrome (SARS) is caused by a new coronavirus. Genomic sequence analysis will provide the molecular epidemiology and help to develop vaccines. METHODS: We developed a rapid method to amplify and sequence the whole SARS-CoV genome from clinical specimens. The technique employed one-step multiplex RT-PCR to amplify the whole SARS-CoV genome, and then nested PCR was performed to amplify a 2-kb region separately. The PCR products were sequenced. RESULTS: We sequenced the genomes of SARS-CoV from 3 clinical specimens obtained in Taiwan. The sequences were similar to those reported by other groups, except that 17 single nucleotide variations and two 2-nucleotide deletions, and a 1-nucleotide deletion were found. All the variations in the clinical specimens did not alter the amino acid sequence. Of these 17 sequenced variants, two loci (positions 26203 and 27812) were segregated together as a specific genotype - T:T or C:C. Phylogenetic analysis showed two major clusters of SARS patients in Taiwan. CONCLUSION: We developed a very economical and rapid method to sequence the whole genome of SARS-CoV, which can avoid cultural influence. From our results, SARS patients in Taiwan may be infected from two different origins.

Abnormal expression of period 1 (PER1) in endometrial carcinoma.

The development of endometrial carcinoma (EC) is a multiple-step process, which includes inactivation of tumour suppressor genes, activation of oncogenes, and disturbance of cancer-related genes. Recent studies have shown that the circadian cycle may influence cancer development and prognosis. In this study, the expression of a circadian gene, PER1, was examined in 35 ECs and paired non-tumour tissues by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Expression levels of PER1 were significantly decreased in EC, and mutational analysis of the coding regions, together with methylation analysis of cytosine-phosphate guanosine (CpG) sites in the promoter area, was performed to investigate the possible mechanisms. The analyses detected four single nucleotide polymorphisms in both tumour and non-tumour tissues, which had no relationship with the expression of PER1. In the promoter area of the PER1 gene, the CpG sites were methylated in 31.4% of ECs, but in 11.4% of paired non-tumour tissues (p < 0.05). These results suggest that the down-regulation of PER1 expression in EC was partly due to inactivation of the PER1 gene by DNA methylation of the promoter and partly due to other factors. Analysis of the relationships between the expression of PER1, P53, c-MYC, cyclin A, cyclin B, and cyclin D1 showed no definite relationship. These results suggest that down-regulation of the PER1 gene disrupts the circadian rhythm, which may favour the survival of endometrial cancer cells.

Mutational, epigenetic and expressional analyses of caveolin-1 gene in cervical cancers.

Caveolin-1 (CAV-1) protein, an integral membrane protein of caveolae membranes, is highly expressed in terminally differentiated cells and down-regulated in cells transformed by human papilloma virus infection. It may also be involved in the tumorigenesis of cervical cancer. CAV-1 gene is regarded as a candidate for the tumor suppressor gene and it can be inactivated in several ways, including point mutations, chromosomal deletions and promoter methylation. We used direct sequencing, methylation specific PCR, and immunohistochemical staining methods to explore the role of CAV-1 gene in the development of cervical cancer. Our results showed that 4 of 72 cases (6%) had methylated CpG-island on the CAV-1 promoter, 17 of 72 cases (26.1%) having no methylation on the promoter showed no expression of CAV-1 protein, and 2 of 72 cases had a GAC right curved arrow GAT transition polymorphism at codon 82. Three types of CAV-1 expression patterns were observed in cervical cancer tissues, and the expression pattern had no relationship with mutation status. From these results, we suggest that CAV-1 gene can be inactivated through mutations, and does not play a role, through methylation of promoter, or an unknown mechanism which may play a role, in the development of cervical cancer.