Apoptotic effect of dibenzylideneacetone on oral cancer cells via modulation of specificity protein 1 and Bax.

OBJECTIVE: Dibenzylideneacetone (DBA), an analogue of curcumin, has been shown to have potential anticancer effects against several cancers. However, the molecular mechanism underlying anticancer activity of DBA has not been well established yet. In this study, we investigated the function and molecular mechanism of DBA in human oral cancer cells. MATERIALS AND METHODS: The growth-inhibitory and apoptotic effects and related signaling pathways of DBA were evaluated using trypan blue exclusion assay, 4'-6-diamidino-2-phenylindole staining, Western blot analysis, siRNA, and reverse transcription-polymerase chain reaction. RESULTS: DBA inhibited cell growth and induced apoptosis, as evidenced by PARP cleavage, activation of caspase-3, and nuclear condensation. DBA also decreased specificity protein 1 (Sp1) expression through facilitating protein degradation. In addition, DBA enhanced the induction of pro-apoptotic protein Bax, resulting in their conformational change, translocation into mitochondrial outer membrane, and its oligomerization. The down-regulation of Sp1 by siRNA targeting Sp1 and mithramycin A increasingly activated Bax to trigger apoptosis. Moreover, DBA-induced growth inhibition and apoptosis in various human oral cancer cell lines were associated with Sp1 down-regulation and induction of Bax. CONCLUSION: These findings suggest that DBA may be a potential anticancer drug candidate to induce apoptosis through down-regulation of Sp1 in human oral cancer.

Phylogenetic Analysis of a Privately-owned Korean Native Chicken Population Using mtDNA D-loop Variations.

The use of Korean native chicken is increasing, and the discovery of new genetic resources is very important from both economic and genetic conservation points of view. In this study, mtDNA D-loop sequences from 272 privately-owned Korean native chickens from a Hyunin farm were investigated. Seventeen nucleotide substitutions were identified from the sequence analysis and they were classified as 6 haplotypes. Previously investigated haplotypes in five Korean native chicken populations have been compared with the Hyunin chicken population. The results indicated that two haplotypes, H10 and H15, in the Hyunin chicken population were not previously identified in other Korean native chicken populations, representing 33.09% (90/272) and 1.1% (3/272) of the Hyunin population, respectively. On the other hand, four other haplotypes were identical to those of a previous study of Korean native chicken populations. This result is indicative of conservation strategies of Hyunin chicken populations for expanding the genetic diversity in the Korean native chicken population.

Discrimination of korean native chicken lines using fifteen selected microsatellite markers.

In order to evaluate the genetic diversity and discrimination among five Korean native chicken lines, a total of 86 individuals were genotyped using 150 microsatellite (MS) markers, and 15 highly polymorphic MS markers were selected. Based on the highest value of the number of alleles, the expected heterozygosity (He) and polymorphic information content (PIC) for the selected markers ranged from 6 to 12, 0.466 to 0.852, 0.709 to 0.882 and 0.648 to 0.865, respectively. Using these markers, the calculated genetic distance (Fst), the heterozygote deficit among chicken lines (Fit) and the heterozygote deficit within chicken line (Fis) values ranged from 0.0309 to 0.2473, 0.0013 to 0.4513 and -0.1002 to 0.271, respectively. The expected probability of identity values in random individuals (PI), random half-sib (PI half-sibs ) and random sibs (PI sibs ) were estimated at 7.98×10(-29), 2.88×10(-20) and 1.25×10(-08), respectively, indicating that these markers can be used for traceability systems in Korean native chickens. The unrooted phylogenetic neighbor-joining (NJ) tree was constructed using 15 MS markers that clearly differentiated among the five native chicken lines. Also, the structure was estimated by the individual clustering with the K value of 5. The selected 15 MS markers were found to be useful for the conservation, breeding plan, and traceability system in Korean native chickens.

Investigation of MC1R SNPs and Their Relationships with Plumage Colors in Korean Native Chicken.

The melanocortin 1 receptor (MC1R) gene is related to the plumage color variations in chicken. Initially, the MC1R gene from 30 individuals was sequenced and nine polymorphisms were obtained. Of these, three and six single nucleotide polymorphisms (SNPs) were confirmed as synonymous and nonsynonymous mutations, respectively. Among these, three selected SNPs were genotyped using the restriction fragment length polymorphism (RFLP) method in 150 individuals from five chicken breeds, which identified the plumage color responding alleles. The neighbor-joining phylogenetic tree using MC1R gene sequences indicated three well-differentiated different plumage pigmentations (eumelanin, pheomelanin and albino). Also, the genotype analyses indicated that the TT, AA and GG genotypes corresponded to the eumelanin, pheomelanin and albino plumage pigmentations at nucleotide positions 69, 376 and 427, respectively. In contrast, high allele frequencies with T, A and G alleles corresponded to black, red/yellow and white plumage color in 69, 376 and 427 nucleotide positions, respectively. Also, amino acids changes at position Asn23Asn, Val126Ile and Thr143Ala were observed in melanin synthesis with identified possible alleles, respectively. In addition, high haplotype frequencies in TGA, CGG and CAA haplotypes were well discriminated based on the plumage pigmentation in chicken breeds. The results obtained in this study can be used for designing proper breeding and conservation strategies for the Korean native chicken breeds, as well as for the developing breed identification markers in chicken.

Forming mechanism of the bipolar resistance switching in double-layer memristive nanodevices.

To initiate resistance switching phenomena, it is usually necessary to apply a strong electric field to a sample. This forming process poses very serious obstacles in real nanodevice applications. In unipolar resistance switching (URS), it is well known that the forming originates from soft dielectric breakdown. However, the forming in bipolar resistance switching (BRS) is poorly understood. In this study, we investigated the forming processes in Pt/Ta2O5/TaOx/Pt and Pt/TaOx/Pt nanodevices, which showed BRS and URS, respectively. By comparing the double- and single-layer systems, we were able to observe differences in the BRS and URS forming processes. Using computer simulations based on an 'interface-modified random circuit breaker network model', we could explain most of our experimental observations. This success suggests that the BRS forming in our Pt/Ta2O5/TaOx/Pt double-layer system can occur via two processes, i.e., polarity-dependent resistance switching in the Ta2O5 layer and soft dielectric breakdown in the TaOx layer. This forming mechanism can be used to improve the performance of BRS devices. For example, we could improve the endurance properties of Pt/Ta2O5/TaOx/Pt cells by using a small forming voltage.

Spectrum of MR imaging findings in Wernicke encephalopathy: are atypical areas of involvement only present in nonalcoholic patients?

BACKGROUND AND PURPOSE: Although MR imaging is considered the most effective method to confirm a diagnosis of WE, MR imaging studies designed to distinguish WE between NA and AL patients have yielded controversial results. The purpose of this study was to determine potential differences in MR imaging features between AL and NA patients with WE and to compare neurologic symptoms with MR imaging findings. MATERIALS AND METHODS: This retrospective study included 24 consecutive patients (male/female, 15:9; mean age, 54 years) diagnosed with WE in a university hospital (AL = 13, NA = 11). Clinical manifestations and MR imaging findings between AL and NA patients were evaluated. Classic WE symptom triad and consciousness level and MR imaging findings were scored and compared with each other. Statistical analyses were performed with χ(2), Fisher exact, and Spearman tests. RESULTS: No differences were observed regarding the areas of hyperintense signal intensity on FLAIR imaging and enhancement of the mammillary bodies between AL and NA patients (P > .05). Frequent sites of involvement were the medial thalami (86%), dorsal medulla (82%), tectal plate (77%), and the periaqueductal gray matter (75%). A positive association was found between the consciousness levels of the patients and the involvement of atypical sites (P = .01). Only 4 of the 24 patients (17%) had all 3 symptoms of the classic WE symptom triad. CONCLUSIONS: MR imaging features of WE may not be different between AL and NA patients. The medulla is 1 of the most frequently involved sites, and consciousness level is also associated with atypical site involvement.

Scaling theory for unipolar resistance switching.

We investigate a reversible percolation system showing unipolar resistance switching in which percolating paths are created and broken alternately by the application of an electric bias. Owing to the dynamical changes in the percolating paths, different from those in classical percolating paths, a detailed understanding of the structure is demanding and challenging. Here, we develop a scaling theory that can explain the transport properties of these conducting paths; the theory is based on the fractal geometry of a percolating cluster. This theory predicts that two scaling behaviors emerge, depending on the topologies of the conducting paths. We confirm these theoretical predictions experimentally by observing material-independent universal scaling behaviors in unipolar resistance switching.

An investigation of the impact of the location and timing of antigen-specific T cell division on airways inflammation.

It is widely accepted that allergic asthma is orchestrated by T helper type 2 lymphocytes specific for inhaled allergen. However, it remains unclear where and when T cell activation and division occurs after allergen challenge, and whether these factors have a significant impact on airways inflammation. We therefore employed a CD4-T cell receptor transgenic adoptive transfer model in conjunction with laser scanning cytometry to characterize the location and timing of T cell division in asthma in vivo. Thus, for the first time we have directly assessed the division of antigen-specific T cells in situ. We found that accumulation of divided antigen-specific T cells in the lungs appeared to occur in two waves. The first very early wave was apparent before dividing T cells could be detected in the lymph node (LN) and coincided with neutrophil influx. The second wave of divided T cells accumulating in lung followed the appearance of these cells in LN and coincided with peak eosinophilia. Furthermore, accumulation of antigen-specific T cells in the draining LN and lung tissue, together with accompanying pathology, was reduced by intervention with the sphingosine 1-phosphate receptor agonist FTY720 2 days after challenge. These findings provide greater insight into the timing and location of antigen-specific T cell division in airways inflammation, indicate that distinct phases and locations of antigen presentation may be associated with different aspects of pathology and that therapeutics targeted against leukocyte migration may be useful in these conditions.

The control of cell adhesion and viability by zinc oxide nanorods.

The ability to control the behavior of cells that interact with implanted biomaterials is desirable for the success of implanted devices such as biosensors or drug delivery devices. There is a need to develop materials that can limit the adhesion and viability of cells on implanted biomaterials. In this study, we investigated the use of zinc oxide (ZnO) nanorods for modulating the adhesion and viability of NIH 3T3 fibroblasts, umbilical vein endothelial cells, and capillary endothelial cells. Cells adhered far less to ZnO nanorods than the corresponding ZnO flat substrate. The few cells that adhered to ZnO nanorods were rounded and not viable compared to the flat ZnO substrate. Cells were unable to assemble focal adhesions and stress fibers on nanorods. Scanning electron microscopy indicated that cells were not able to assemble lamellipodia on nanorods. Time-lapse imaging revealed that cells that initially adhered to nanorods were not able to spread. This suggests that it is the lack of initial spreading, rather than long-term exposure to ZnO that causes cell death. We conclude that ZnO nanorods are potentially useful as an adhesion-resistant biomaterial capable of reducing viability in anchorage-dependent cells.

GaN, ZnO and InN nanowires and devices.

A brief review is given of recent developments in wide bandgap semiconductor nanowire synthesis and devices fabricated on these nanostructures. There is strong interest in these devices for applications in UV detection, gas sensors and transparent electronics.

Does microbleed predict haemorrhagic transformation after acute atherothrombotic or cardioembolic stroke?

OBJECTIVES: Cerebral microbleeds (MBs) are known to be indicative of bleeding-prone microangiopathy and may predict incident intracerebral haemorrhage. However, there is controversy concerning the causal relationship between the presence of MBs and haemorrhagic transformation (HTf) after ischaemic stroke. METHODS: Of the 1034 patients with acute ischaemic stroke who were consecutively admitted to our hospital, 377 patients with stroke due to large-artery atherothrombosis or cardioembolism were selected for participation in this study. We examined the MBs using T2*-weighted gradient-echo MRI performed within 24 hours after admission, and the incidence of HTf was assessed using follow-up brain MRI during the hospitalisation period. RESULTS: Of the 377 patients with stroke, 234 were male (62.1%) and the mean age was 66.2 +/-11.7 years. MBs were initially found in 109 patients (28.9%), and newly incident HTf was noted during the hospitalisation period in 74 patients (19.6%). The presence of MBs was not increased in the patients with HTf (24.3% vs. 30.0% in the patients without HTf; p = 0.331). In addition, the number of MBs was not higher in the patients with HTf (0.7+/-1.5 vs. 1.8+/-8.1; p = 0.234). This lack of significance between MBs and HTf persisted after stratification by stroke mechanism. CONCLUSIONS: This study suggests that underlying MBs do not predict incident HTf after acute ischaemic stroke. The clinical significance of MBs should be differentially evaluated according to the type of disease (intracerebral haemorrhage vs. HTf).

Tumour necrosis factor-alpha blockade suppresses murine allergic airways inflammation.

Asthma is a heterogeneous disease that has been increasing in incidence throughout western societies and cytokines, including proinflammatory tumour necrosis factor alpha (TNF-alpha), have been implicated in the pathogenesis of asthma. Anti-TNF-alpha therapies have been established successfully in the clinic for diseases such as rheumatoid arthritis and Crohn's disease. TNF-alpha-blocking strategies are now being trialled in asthma; however, their mode of action is poorly understood. Based on the observation that TNF-alpha induces lymph node hypertrophy we have attempted to investigate this as a mechanism of action of TNF-alpha in airway inflammation by employing two models of murine airway inflammation, that we have termed short and long models, representing severe and mild/moderate asthma, respectively. The models differ by their immunization schedules. In the short model, characterized by eosinophilic and neutrophilic airway inflammation the effect of TNF-alpha blockade was a reduction in draining lymph node (DLN) hypertrophy, eosinophilia, interleukin (IL)-5 production and immunoglobulin E (IgE) production. In the long model, characterized by eosinophilic inflammation, TNF-alpha blockade produced a reduction in DLN hypertrophy and IL-5 production but had limited effects on eosinophilia and IgE production. These results indicate that anti-TNF-alpha can suppress DLN hypertrophy and decrease airway inflammation. Further investigations showed that anti-TNF-alpha-induced inhibition of DLN hypertrophy cannot be explained by preventing l-selectin-dependent capture of lymphocytes into the DLN. Given that overall TNF blockade was able to suppress the short model (severe) more effectively than the long model (mild/moderate), the results suggest that TNF-alpha blocking therapies may be more effective in the treatment of severe asthma.

A breath of fresh air? Report of the 2003 British Thoracic Society Winter Meeting.

An overview of some of the key topics presented at the BTS Winter Meeting held in London on 3-5 December 2003.

The prevalence of the mitochondrial DNA 16189 variant in non-diabetic Korean adults and its association with higher fasting glucose and body mass index.

AIMS: To evaluate the prevalence of the 16189 variant of mitochondrial DNA in Korean adults and its association with insulin resistance. METHODS: We investigated 160 non-diabetic subjects from a community-based diabetes survey conducted in Yonchon County, Korea in 1993. We extracted the DNA from peripheral blood and examined the 16189 variant by polymerase chain reaction and restrictive enzyme digestion. We compared body mass index (BMI), blood pressure, fasting plasma glucose, 2-h plasma glucose after 75 g glucose load, fasting insulin, cholesterol, and homeostasis model assessment of insulin resistance and beta-cell function between the subjects with 16189 variant and wild type. RESULTS: The prevalence of the 16189 variant in Korean adults was 28.8% (46 of 160). Subjects with the 16189 variant had higher fasting glucose and BMI than those with wild type, but fasting insulin, homeostasis model assessment of insulin resistance and beta-cell function, cholesterol, and blood pressure were not different between two groups. CONCLUSION: Our results provide evidence for an association of a frequent mitochondrial polymorphism with higher fasting glucose and the risk factors of diabetes mellitus.

Pathogenesis of virus-induced immune-mediated demyelination.

Theiler's murine encephalomyelitis virus-induced demyelinating disease has been extensively studied as an attractive infectious model for human multiple sclerosis. Virus-specific inflammatory Th1 cell responses followed by autoimmune responses to myelin antigens play a crucial role in the pathogenic processes leading to demyelination. Antibody and cytotoxic T cells (CTL) responses to virus appears to be primarily protective from demyelinating disease. Although the role of Th1 and CTL responses in the induction of demyelinating disease is controversial, assessment of cytokines produced locally in the central nervous system (CNS) during the course of disease and the effects of altered inflammatory cytokine levels strongly support the importance of Th1 responses in this virus-induced demyelinating disease. Induction of various chemokines and cytokines in different glial and antigen presenting cells upon viral infection appears to be an important initiation mechanism for inflammatory Th1 responses in the CNS. Coupled with the initial inflammatory responses, viral persistence in the CNS may be a critical factor for sustaining inflammatory responses and consequent immune-mediated demyelinating disease.

A survey of heterobasidiomycetous yeasts for the presence of the genes homologous to virulence factors of Filobasidiella neoformans, CNLAC1 and CAP59.

Among species of the heterobasidiomycetous yeasts, Filobasidiella neoformans is the only serious pathogen that causes fatal infections in both immunocompromised as well as immunocompetent patients. Three phenotypic characteristics, including growth at 37 degrees C, extracellular polysaccharide capsule and laccase activity, of F. neoformans are known to play major roles in the pathogenicity of the fungus. Several CAP genes involved in polysaccharide capsule formation, as well as the CNLAC1 gene encoding a laccase, have previously been cloned and characterized. To analyse the presence of these Cryptococcus neoformans virulence factors in other heterobasidiomycetous yeasts, numerous species of heterobasidiomycetous yeasts were screened for the presence of laccase activity and a polysaccharide capsule. Species exhibiting laccase activity and possessing a glucuronoxylomannan (GXM) capsule were screened for homologues of both the CAP59 gene and the CNLAC1 gene of F. neoformans. Southern blots of genomic DNA from GXM capsule-producing species exhibited no discernible hybridization to the CAP59 DNA sequence except for the two varieties of F. neoformans and Cryptococcus podzolicus. Although discernible, the hybridization band observed with the DNA of C. podzolicus was faint. Oligonucleotide primers constructed using the CAP59 gene sequence also failed to yield PCR products from DNAs of these yeasts except for the two varieties of F. neoformans. These results, coupled with the absence of a CAP59 homologue in the database, suggested the CAP59 gene to be unique to F. neoformans. C. podzolicus was the only species besides F. neoformans that possessed a capsule and expressed strong laccase activity on various media containing phenolic compounds. A CNLAC1 homologue was isolated from C. podzolicus while it was not detected in the species producing beige to faint tan colonies on media with phenolic compounds. Compared to the CNLAC1 sequence of four serotypes of F. neoformans, the CNLAC1 homologue of C. podzolicus showed the highest homology to that of serotype B/C strains and the lowest homology to that of serotype A strains.

Enhanced susceptibility to Theiler's virus-induced demyelinating disease in perforin-deficient mice.

Theiler's virus induces immune-mediated demyelinating disease similar to human MS in susceptible mice. Though the MHC class II-restricted T cell response is critical, susceptibility/resistance is also associated with a MHC class I haplotype. Here we report that perforin-deficient C57BL/6 mice (pKO) are susceptible to demyelination and develop clinical disease. The levels of primary demyelination, proliferation, Th1 responses, and viral load were also markedly enhanced. In addition, immunization of pKO mice with UV-inactivated virus further enhanced clinical incidence and accelerated the disease course. Thus, perforin is most likely involved in viral clearance, hence protection from the disease.

Inhibitory effects of anti-inflammatory drugs on interleukin-6 bioactivity.

Interleukin-6 (IL-6) is known as a proinflammatory cytokine involved in immune response, inflammation, and hematopoiesis. Inhibitory effects of anti-inflammatory drugs on IL-6 bioactivity using IL-6-dependent hybridoma have been evaluated. Three out of 16 nonsteroidal anti-inflammatory drugs (NSAIDs) showed IC50 values of less than 100 microM, which were in the order of oxyphenylbutazone hydrate (IC50=7.5 microM)>meclofenamic acid sodium salt (31.9 microM)>sulindac (74.9 microM). Steroidal anti-inflammatory drugs (SAIDs) exhibited significant inhibitory effects at 100 microM on the IL-6 bioactivity, and their inhibitory potencies were in the order of budesonide (IC50=2.2 microM)>hydrocortisone 21-hemisuccinate (6.7 microM), prednisolone (7.5 microM), betamethasone (10.9 microM)>dexamethasone (18.9 microM) and triamcinolone acetonide (24.1 microM). The results would provide an additional mechanism by which anti-inflammatory drugs display their anti-inflammatory and immunosuppressive effects at higher concentrations.

NMDA recepter-mediated neuroprotection by essential oils from the rhizomes of Acorus gramineus.

Acori graminei Rhizoma (AGR) is shown to exhibit a number of pharmacological actions including sedation and anticonvulsive action. To further characterize its actions in the CNS, the present study evaluated the effects of essential oils (EO) from AGR on the excitotoxic neuronal cell death induced in primary rat cortical cell cultures. EO inhibited the glutamate-induced excitotoxicity in a concentration-dependent manner, with the IC50 of 0.241 mg/ml. EO exerted more potent neuroprotection against the toxicity induced by NMDA (IC50 = 0.139 mg/ml). In contrast, the AMPA-induced toxicity was not inhibited by EO. Receptor-ligand binding studies were performed to investigate the neuroprotective action mechanism. EO dramatically inhibited the specific bindings of a use-dependent NMDA receptorion channel blocker [3H]MK-801, indicating an NMDA receptor antagonist-like action. However, the bindings of [3H]MDL 105,519, a ligand selective for the glycine binding site of NMDA receptor, were not considerably inhibited. These results demonstrated that EO extracted from AGR exhibited neuroprotective effects on cultured cortical neurons through the blockade of NMDA receptor activity, and that the glycine binding site appeared not to be the major site of action.