Optical bistability in subwavelength compound metallic grating

We have investigated the optical bistability behavior based on an electromagnetically induced reflection (EIR) effect in a compound metallic grating consisting of subwavelength slits and Kerr nonlinear nanocavities embedded in a metallic film. The theoretical and simulation results show that a narrow peak in the broad reflection dip possesses a red-shift with increasing the refractive index of coupled nanocavities. Importantly, we have obtained an obvious optical bistability with threshold intensity about ten times lower than that of metallic grating coated by nonlinear material. The results indicate that our structure may find excellent applications for nonlinear plasmonic devices, especially optical switches and modulators.

Total blood volume of Asian patients undergoing cardiac surgery is far from that predicted by conventional methods

AIM

Current cardiopulmonary bypass (CPB) procedures use non-hematic fluids to prime bypass circuits, often resulting in marked hemodilution. Patients' total blood volume (TBV) is estimated prior to hemodilution. We aimed to evaluate differences between calculation of TBV by Nadler's formula, a classic reference book method, and an established formula calculated by the authors.

METHODS

A total of 285 patients of Asian origin received primary cardiac surgery between September 2010 and October 2011 in our institution. Patients' total blood volume was estimated by: 1) standard Nadler formula: TBV (men) =0.417H3+0.045TBM-0.030L TBM (total body mass, Kg); TBV (women) =0.414H3+0.0328 TBM-0.030L; 2) classic reference book method: patient's weight in kilograms times 7% (women) or 7.5% (men); and 3) our practical calculation: TBV=HCT2*(CPB prime volume + intravenous fluids before CPB - urine volume before CPB)/(HCT1- HCT2).

RESULTS

Bland-Altman plotting revealed no mean differences between Nadler formula and reference book TBV measurements (Figure 1A). Differences in means (95% limit of agreement) for reference book/Nadler formulas was 0.52 (-0.21, 1.24, N.=285). Comparing authors' results with those of reference book/Nadler, TBV yielded divergent results. TBV correlated positively to patient's height (P=0.001) and body surface area (P<0.01), and correlated positively to height after controlling for age and gender (β=87.3, SE=42.9, P=0.043).

CONCLUSION

Total blood volume of Asian patients calculated by the authors differs markedly from that estimated by Nadler and classic reference book formulas, which suggests that more accurate calculation of TBV is needed for Asian cardiac patients requiring CPB, especially patients with valvular disease.

Polymorphisms of rs1799983 (G>T) and rs1800780 (A>G) of the eNOS gene associated with susceptibility to essential hypertension in the Chinese Hui ethnic population

We investigated a possible association of polymorphism of the eNOS gene and essential hypertension in the Chinese Hui population; polymorphisms of rs2070744 (T>C), rs1799983 (G>T), rs1800780 (A>G), and rs3918181 (A>G) loci of the eNOS gene were examined. We found that the genotypic frequencies at rs1799983 and rs1800780 loci differed significantly between patients with essential hypertension and control cohorts. The allelic frequency of the rs1799983 locus also differed significantly between essential hypertension patients and non-essential hypertension controls in this population. Additionally, the G allele of the rs1799983 locus was less frequent in the essential hypertension patients than in controls, with an odds ratio (OR) value of 3.851 [95% confidence interval (95%CI) = 2.236-6.631]. This is an indication of a protective factor of essential hypertension in Chinese Hui people. Haplotype analysis using the 4 SNPs revealed 15 haplotypes. Haplotype frequencies of CGAG, TTAG, TGGG, TTGG, and TTGA were significantly different in essential hypertension patients compared to non-essential hypertension controls. Individuals with haplotypes CGAG [χ² = 7.371, OR (95%CI) = 0.352 (0.161-0.770)] and TGGG [χ² = 6.180, OR (95%CI) = 0.600 (0.400- 0.899)] appear less likely to have essential hypertension. However, Chinese Hui with the haplotype TTAG are at risk to develop essential hypertension [χ² = 10.816, OR (95%CI) = 2.689 (1.466-4.932)]. We conclude that polymorphism of the eNOS gene is associated with susceptibility to essential hypertension in the Chinese Hui population.

Four new sesquiterpenes from the stems of Pogostemon cablin

Four new sesquiterpenes (1-4), together with four known compounds (5-8), were isolated from the stems of Pogostemon cablin (Blanco.) Benth. Their chemical structures were elucidated by means of spectroscopic methods, including 1D and 2D NMR, HRESIMS, IR, and UV. Hepatoprotective activities of these compounds were investigated, by studying the protective effect on HL-7702 cellular injury induced by dl-galactosamine.

Serine protease and ovarian paracrine factors in regulation of ovulation

The controlled target extracellular matrix (ECM) degradation generated by serine protease and regulated by serine protease inhibitor and ovarian paracrine/autocrine factors is an event that affects a wide variety of physiological and pathological processes in the ovary. Evidence cumulated in the past decade clearly showed that the hormone-induced coordinated expression of the tissue-type PA (tPA) produced mainly by granulosa cells and oocyte, and its inhibitor PAI-1 secreted by theca cells in the preovulatory follicles may be responsible for a controlled and directed proteolysis leading to the rupture of selected follicles in the rat, monkey and other mammals. In recent years increasing evidence further demonstrated that oocyte maturation and ovulation may also be modulated by other serine protease and inhibitor, as well as endogenously- produced ovarian paracrine/autocrine factors. Thus, it is important to identify the interrelationship between the serine protease system and the multiple factors, and to know how they regulate the ovarian physiological and pathological processes during oocyte maturation and ovulation.

Passively Q-switched Nd:Sc0.2Y0.8SiO5 dual-wavelength laser with the orthogonally polarized output

We have demonstrated a laser-diode pumped continuous-wave (CW) and passively Q-switched laser with a Nd:Sc(0.2)Y(0.8)SiO(5) (Nd:SYSO) crystal for the first time. In the CW operation, the laser was found to oscillate in tri-wavelength regime at 1074.8 nm, 1076.6 nm and 1078.2 nm, respectively. The maximum CW output power of 1.96 W was obtained, giving an optical-to-optical conversion efficiency of 35% and a slope efficiency of 39%. Using either Cr(4+):YAG or V(3+):YAG crystal as saturable absorber, stable passively Q-switched laser was obtained at dual-wavelength of 1074.8 nm and 1078.2 nm with orthogonal-polarization. The maximum average output power, pulse repetition rate, and shortest pulse width were 1.03 W, 50 kHz, and 24 ns, respectively. The passively Q-switched dual-wavelength laser could be potentially used as a source for generation of terahertz radiation.

Comparative analyses of genetic/epigenetic diversities and structures in a wild barley species (Hordeum brevisubulatum) using MSAP, SSAP and AFLP

We analyzed genetic diversity and population genetic structure of four artificial populations of wild barley (Hordeum brevisubulatum); 96 plants collected from the Songnen Prairie in northeastern China were analyzed using amplified fragment length polymorphism (AFLP), specific-sequence amplified polymorphism (SSAP) and methylation-sensitive amplified polymorphism (MSAP) markers. Indices of (epi-)genetic diversity, (epi-)genetic distance, gene flow, genotype frequency, cluster analysis, PCA analysis and AMOVA analysis generated from MSAP, AFLP and SSAP markers had the same trend. We found a high level of correlation in the artificial populations between MSAP, SSAP and AFLP markers by the Mantel test (r > 0.8). This is incongruent with previous findings showing that there is virtually no correlation between DNA methylation polymorphism and classical genetic variation; the high level of genetic polymorphism could be a result of epigenetic regulation. We compared our results with data from natural populations. The population diversity of the artificial populations was lower. However, different from what was found using AFLP and SSAP, based on MSAP results the methylation polymorphism of the artificial populations was not significantly reduced. This leads us to suggest that the DNA methylation pattern change in H. brevisubulatum populations is not only related to DNA sequence variation, but is also regulated by other controlling systems.

PpPIF-1: first isolated full-length PIF-like element from the bamboo Phyllostachys pubescens

PIF-like elements are the first-described members of a recently discovered and widespread superfamily of DNA transposons, named PIF/Harbinger. Complete and partial PIF-like elements have been isolated from hundreds of plant species. Previously, we identified 139 partial PIF-like transposases in the Bambusoideae, of which three were from the bamboo species Phyllostachys pubescens. Here we report identification and isolation of the first full-length PIF-like element (PpPIF-1) from P. pubescens; identification was made by chromosome walking, based on a modified magnetic enrichment procedure that allows efficient cloning of flanking sequences up to 3 kb in length. PpPIF-1 is 5953 bp in length, with 20-bp imperfect inverted terminal repeats and 3-bp target site duplications. This element contains two open reading frames, one encoding a putative transposase, including the complete DDE-domain typical of PIF/Harbinger elements from plants, and the other encoding a DNA-binding protein. There are seven termination codons and two frameshift mutations in the open reading frames, probably due to vertical inactivation.

Generation of photorealistic 3D image using optical digitizer

A technique to generate a photorealistic three-dimensional (3D) image and color-textured model using a dedicated optical digitizer is presented. The proposed technique is started with the range and texture image acquisition from different viewpoints, followed by the registration and integration of multiple range images to get a complete and nonredundant point cloud that represents a real-life object. The accuracy of the range image and the precision of correspondence between the range image and texture image are guaranteed by sensor system calibration. Based on the point cloud, a geometric model is established by considering the connectivity of adjacent range image points. In order to enhance the photorealistic effect, we suggest a texture blending technique that utilizes a composite-weight strategy to blend the texture images within the overlapped region. This technique allows more efficient removal of the artifacts existing in the registered texture image, leading to a 3D image with photorealistic quality and color-texture modeling. Experimental results are also presented to testify to the validity of the proposed method.

Polymorphisms of the TIM-1 gene are associated with rheumatoid arthritis in the Chinese Hui minority ethnic population

The T-cell immunoglobulin and mucin domain 1 (TIM-1) is known to be associated with susceptibility to rheumatoid arthritis (RA). We investigated the association of four single-nucleotide polymorphisms (SNPs) in the promoter region of the TIM-1 gene with susceptibility to RA in a Chinese Hui ethnic minority group. Using RFLP or sequence specific primer-PCR, 118 RA patients and 118 non-arthritis control individuals were analyzed for the -1637A>G, -1454G>A, -416G>C, and -232A>G SNPs in the TIM-1 gene. The polymorphisms -232A>G and -1637A>G in the promoter region of TIM-1 were found to be associated with susceptibility to the RA gene in the Hui population, while -416G>C and -1454G>A SNPs were not. Of these, the polymorphism of -232A>G is inconsistent with that found in a Korean population, suggesting that genetic variations of the TIM-1 gene contribute to RA susceptibility in different ways among different populations. Based on haplotype analysis, individuals with haplotypes AGCA (Χ(2) = 22.0, P < 0.01, OR (95%CI) >1), AGCG (Χ(2) = 18.16, P < 0.01, OR (95%CI) >1) and AGGA (Χ(2) = 5.58, P < 0.05, OR (95%CI) >1) are at risk to develop RA in the Chinese Hui population; those with the GAGA (Χ(2) = 7.44, P < 0.01, OR (95%CI) <1) haplotype may have a decreased likelihood of RA. GGCA and GGCG are more common in both RA and non-RA subjects. We conclude that -1637A>G and -232A>G polymorphisms of TIM-1 are associated with susceptibility to RA in the Chinese Hui population.

Transposable elements in Phyllostachys pubescens (Poaceae) genome survey sequences and the full-length cDNA sequences, and their association with simple-sequence repeats

Phyllostachys pubescens is a woody bamboo with the highest ecological, economic, and cultural values of all bamboos in Asia. There is more genomic data available for P. pubescens than for any other bamboo species, including 2.12-Mb genome survey sequences (GSS) and 11.4-Mb full-length cDNA sequences (FL-cDNAs) currently deposited in GenBank. Analysis of these sequences revealed that transposable elements (TEs) are abundant, diverse and polyphyletic in the P. pubescens genome, of which Ty3-gypsy and Ty1-copia are the two most abundant families. Phylogenic analysis showed that both elements probably arose before the Bambusoideae separated from the other Poaceae subfamilies. We found evidence that the distribution of some intragenic TEs correlated with transcript profiles, of which Mutator elements preferred to insert in the transcripts of transcription factors. Additionally, we found that the abundance of SSRs in TEs (4.56%) was significantly higher than in GSS (0.098%) and in FL-cDNAs (2.60%) in P. pubescens genome, and TA/AT and CT/AG repeats were found to be intimately associated with En/Spm and Mutator elements, respectively. Our data provide a glimpse of the structure and evolution of P. pubescens genome, although large-scale sequencing of the genome would be required to fully understand the architecture of the P. pubescens genome.

Influence of consumption of probiotics on the plasma lipid profile: a meta-analysis of randomised controlled trials

AIMS

Human clinical studies have yielded mixed results on the effects of consumption of probiotics on the plasma lipid profile. We conducted a meta-analysis of randomised controlled trials that evaluated the effects of probiotics consumption on blood lipids.

DATA SYNTHESIS

A systematic literature search of Embase, Web of Science, PubMed and Cochrane Controlled Trials Registry was conducted for studies that investigated the efficacy of probiotics on the plasma lipid profile of subjects. With the help of Review Manager 4.2, data from 13 trials, which included 485 participants with high, borderline high and normal cholesterol levels, were examined. The pooled mean net change in total cholesterol for those treated with probiotics compared to controls was -6.40 mg dl(-1) (95% confidence interval (CI), -9.93 to -2.87), mean net change in low-density lipoprotein (LDL) cholesterol was -4.90 mg dl(-1) (95% CI, -7.91 to -1.90), mean net change in high-density lipoprotein (HDL) cholesterol was -0.11 mg dl(-1) (95% CI, -1.90-1.69) and mean net change in triglycerides was -3.95 mg dl(-1) (95% CI, -10.32-2.42).

CONCLUSION

These results indicate that a diet rich in probiotics decreases total cholesterol and LDL cholesterol concentration in plasma for participants with high, borderline high and normal cholesterol levels.

Molecular cloning of HSP70 in Mycoplasma ovipneumoniae and comparison with that of other mycoplasmas

Mycoplasma ovipneumoniae, a bacterial species that specifically affects ovine and goat, is the cause of ovine infectious pleuropneumonia. We cloned, sequenced and analyzed heat shock protein 70 (HSP70) (dnaK) gene of M. ovipneumoniae. The full length open reading frame of the M. ovipneumoniae HSP70 gene consists of 1812 nucleotides, with a G+C content of 34.16%, encoding 604 amino acids. Comparative analysis with the HSP70 sequences of 15 Mycoplasma species revealed 59 to 87% DNA sequence identity, with an amino acid sequence identity range of 58 to 94%. M. ovipneumoniae and M. hyopneumoniae shared the highest DNA and amino acid sequence identity (87 and 94%, respectively). Based on phylogenetic analysis, both the DNA and amino acid identities of M. ovipneumoniae with other mycoplasmal HSP70 were correlated with the degree of relationship between the species. The C-terminus of the HSP70 was cloned into a bacterial expression vector and expressed in Escherichia coli cells. The recombinant C-terminal portion of HSP70 protein strongly reacted with convalescent sera from M. ovipneumoniae-infected sheep, based on an immunoblotting assay. This indicates that HSP70 is immunogenic in a natural M. ovipneumoniae infection and may be a relevant antigen for vaccine development.

Use of EBSD to study electropulsing induced reverse phase transformations in a Zn-Al alloy (ZA22)

Multi-phase identification and phase transformations in electropulsing treated Zn-Al based alloy wire specimens were studied using electron back-scattered diffraction, back-scattered scanning electron microscopy and X-ray diffraction techniques. By using electron back-scattered diffraction, two phases: η'(S) and η'(T) with a small difference of about 1% in lattice parameters (c(0)/a(0) ) were identified, based on the determined lattice parameters of the phases, and the reverse eutectoid phase transformations: η'(T) +ɛ'(T) +α'(T) →η'(S) and ɛ+α→T'+η were successfully detected. Electron back-scattered diffraction appeared to be an effective technique for studying complex electropulsing induced phase transformations.

Electrical properties and far infrared optical conductivity of boron-doped single-walled carbon nanotube films

Here we report a new approach for producing clean and homogeneous boron-doped single-walled carbon nanotubes. This approach combines the homogeneous dispersion of B(n)O(m)(+) ionic molecules over the nanotube surfaces in a liquid solution, with a high temperature chemical reaction that incorporates the boron atoms into the sp(2) carbon network of the nanotube wall. A comparative study of sheet resistance versus optical transmission in nanotube network films with and without boron-doping is also presented. Although electron energy loss spectroscopy revealed very low B-doping levels (<1 at.%), the dc conductivity of doped samples was raised by a factor of 3.4. Changes in the free carrier contribution to the optical conductivity of single-walled carbon nanotube (SWCNT) films induced by boron-doping was also studied via optical transmission in the far-infrared (IR) (50-7000 cm(-1)). A Drude model was fitted to the changes in the far-IR conductivity to quantify the additional free carrier concentration induced by the B-doping.

Correlation between disc displacements and locations of disc perforation in the temporomandibular joint

OBJECTIVES

The aim of this study was to investigate the correlation between disc displacement types and locations of disc perforation in the temporomandibular joint (TMJ).

METHODS

157 patients (162 joints) with disc perforation observed through arthroscopy were included in this study. The types of disc displacement were analysed by TMJ MRI before operation. The locations of disc perforation under arthroscopy were recorded. The correlation between types of disc displacement and locations of disc perforation was analysed by Fisher's exact test.

RESULTS

Medial disc perforation was observed in 55.6% of patients with anterolateral displacement without reduction, but was observed in only 3.7% of patients with pure anterior displacement, and was not observed in patients with anteromedial displacement without reduction. There was a statistically significant difference between these groups in the incidence of medial disc perforation.

CONCLUSIONS

There is a correlation between different disc displacements and locations of disc perforation. The incidence of medial disc perforation in patients with anterolateral displacement was significantly higher. The types of disc displacement may have direct influence over the locations of disc perforation.

Compact all-fiber high-energy fiber laser with sub-300-fs duration

We report a compact all-fiber high-energy fiber laser that consists of a laser oscillator and a compression section. The laser oscillator generates the pulses with high energy and large chirp. The compression section is made of a piece of standard single-mode fiber that dechirps the chirped pulses. The compact all-fiber fiber laser produces pulses with 8 nJ of the pulse energy and 290 fs of the pulse duration.

Nano-scale surface morphology, wettability and osteoblast adhesion on nitrogen plasma-implanted NiTi shape memory alloy

Plasma immersion ion implantation (PIII) is an effective method to increase the corrosion resistance and inhibit nickel release from orthopedic NiTi shape memory alloy. Nitrogen was plasma-implanted into NiTi using different pulsing frequencies to investigate the effects on the nano-scale surface morphology, structure, wettability, as well as biocompatibility. X-ray photoelectron spectroscopy (XPS) results show that the implantation depth of nitrogen increases with higher pulsing frequencies. Atomic force microscopy (AFM) discloses that the nano-scale surface roughness increases and surface features are changed from islands to spiky cones with higher pulsing frequencies. This variation in the nano surface structures leads to different surface free energy (SFE) monitored by contact angle measurements. The adhesion, spreading, and proliferation of osteoblasts on the implanted NiTi surface are assessed by cell culture tests. Our results indicate that the nano-scale surface morphology that is altered by the implantation frequencies impacts the surface free energy and wettability of the NiTi surfaces, and in turn affects the osteoblast adhesion behavior.

Hepatic and renal artery rupture due to Aspergillus and Mucor mixed infection after combined liver and kidney transplantation: a case report

Fungal infection is a major cause of death in patients who undergo organ transplantation. The incidence of Aspergillus or Mucor infection is low compared with Candida species. We report a case in which Aspergillus and Mucor infected both the hepatic and renal arteries, leading the 2 arteries to rupture at the same time. The patient died 4 days after the second operation. We review the recent literature about this topic and explore the possible route of transmission in our patient. We also discuss the prophylactic methods for Aspergillus and Mucor infections.

Adhesive growth of pancreatic islet cells on a polyglycolic acid fibrous scaffold

BACKGROUND

The use of cultured pancreatic islet cells for diabetes treatment offers several advantages. In theory, cultured cells show greater purity and lower immunogenicity. However, cultured islet cells display a low survival rate in vitro. In the present study we grew islet cells on a polyglycolic acid (PGA) fibrous scaffold to promote cell adhesion, growth, and viability during prolonged culture.

METHODS

Islets isolated from Wistar rat pancreata were digested with collagenase and purified by the Ficoll method. Cells were grown in culture with or without PGA scaffolds. Islet cell purity was determined using a dithizone stain; viability and survival rates were determined using an AO-PI stain. The insulin-secretion index was detected using radioimmunodetection and the growth on an adhesive scaffold analyzed using an inverted microscope and scanning electron microscope (SEM).

RESULTS

In contrast to the scaffold-free control group, cells cultured on PGA scaffolds exhibited improved morphology, less cell death, and prolonged survival times. Cell viability and survival rates were significantly increased in scaffolded cells when compared to control cells (P < .05). Increased insulin secretion was observed in the culture solution of scaffolded cells following stimulation with low glucose (5.6 mmol/L) versus high glucose (16.7 mmol/L). The secretion indices of the two groups were significantly different (P < .05). Islet cell growth, as observed under SEM, was tightly circumvolute, adhesive, and three-dimensional.

CONCLUSIONS

The present results demonstrated that islet cells can successfully grow and survive in culture on a PGA scaffold. These cells exhibited enhanced viability, survival, and insulin secretion.

Transparent boron-doped carbon nanotube films

We report results of studies on the sheet resistance and optical transmission of thin films of boron-doped single-walled carbon nanotubes (SWNTs). Boron doping was carried out by exposure of SWNTs to B 2O 3 and NH 3 at 900 degrees C and 1-3 atom % boron was found in the SWNT bundles via electron energy loss spectroscopy (EELS). Boron doping was found to downshift the positions of the optical absorption bands associated with the van Hove singularities (E 11 (s) E 22 (s) and E 11 (m)) by approximately 30 meV relative to their positions in acid-treated and annealed SWNTs. Raman spectroscopy, EELS, and optical data are consistent with the picture that a few atom % boron has been substituted for carbon in the sp (2) framework of SWNTs. Finally, our results show that boron doping does not significantly affect the optical transmittance in the visible region. However, boron doping lowers the sheet resistance by approximately 30% relative to pristine SWNT films from the same batch. Boron-doped SWNT may provide a better approach to touch-screen technology.

De-repression of the p21 promoter in prostate cancer cells by an isothiocyanate via inhibition of HDACs and c-Myc

Natural isothiocyanates from cruciferous vegetables have been described as important dietary factors for prostate cancer prevention. Phenethyl isothiocyanate (PEITC), found rich in watercress, induces growth arrest and apoptosis in prostate cancer cells, and also inhibits the testosterone-mediated growth of prostates by regulating the androgen receptor and cell cycle progression in rats. PEITC has been recently identified as an inhibitor of histone deacetylases (HDACs). Herein we describe the mechanism of PEITC-mediated growth attenuation in relation to HDAC inhibition in human prostate cancer cells. Exposure of androgen-dependent prostate cancer cells LNCaP to PEITC resulted in cell cycle arrest and a p53-independent up-regulation of the inhibitors of cyclin-dependent kinases, including p21WAF1 and p27. The mechanism of p21 activation was investigated. PEITC significantly enhanced histone acetylation and induced selective modification of histone methylation for chromatin remodeling. Chromatin immunoprecipitation revealed that the p21 gene was associated with the PEITC-induced hyperacetylated histones. As a result, the chromatin unfolding permitted the transcription activation of the p21 gene. PEITC also significantly reduced the expression of c-Myc which represses p21. Pull-down assays using Sp1 affinity oligo beads of the p21 promoter, showed decreased c-Myc binding to the Sp1 transcriptional complexes in the p21 promoter, resulting in reduced p21 repression. The quantity of PEITC (0.5-1 micro M) effective to mediate cell cycle arrest was less than that for inhibiting c-Myc (2-5 micro M), suggesting that the inhibition of HDACs may be the primary mechanism for p21 activation. The PEITC-mediated growth attenuation of prostate cancer cells includes an interactive mechanism involving HDAC and c-Myc inhibition.

Tissue culture-induced locus-specific alteration in DNA methylation and its correlation with genetic variation in Codonopsis lanceolata Benth. et Hook. f

We have reported recently that tissue culture induced a high level of genetic variation at the primary nucleotide sequence in regenerants of medicinal plant Codonopsis lanceolata. It is not known, however, whether epigenetic variation in the form of alteration in DNA methylation also occurred in these plants. Here, we investigated possible alterations in level and pattern of cytosine methylation at the CCGG sites in the same set of regenerants relative to the donor plant, by the MSAP method employing a pair of isoschizomers, HpaII and MspI, which recognize the same restriction site but are differentially sensitive to cytosine methylation at the CCGG sites. A total of 1,674 MSAP profiles were resolved using 39 primer combinations. Of these, 177 (10.5%) profiles were polymorphic among the regenerants and/or between the regenerant(s) and the donor plant, in EcoRI + HpaII or EcoRI + MspI digest but not in both, indicating alteration in cytosine methylation patterns of specific loci, though their estimated total level of methylation remained more or less the same as the donor plant. Gel blot analysis validated most of the variant MSAP profiles as bona fide alteration in methylation patterns. Correlation analysis between the MSAP data and the previously reported ISSR and RAPD data revealed significant correlations, suggesting their possible intrinsic interrelatedness. Thirty-seven typical variant MSAP profiles were isolated and sequenced, of which 5 showed significant homology to known-function genes, 2 to chloroplast sequences, whilst the rest 30 did not find a match in the database.

Dual action on promoter demethylation and chromatin by an isothiocyanate restored GSTP1 silenced in prostate cancer

Prostate carcinoma is characterized by the silencing of pi-class glutathione S-transferase gene (GSTP1), which encodes a detoxifying enzyme. The silencing of GSTP1, due to aberrant methylation at the CpG island in the promoter/5'-UTR, occurs in the vast majority of prostate tumors and precancerous lesions. It is a pathologic marker and probably an underlying cause of oxidative damage and inflammation at tumor initiation. Inhibition of the aberrant promoter methylation could therefore be an effective mean to prevent carcinogenesis. Several isothiocyanates, including phenethyl isothiocyanate (PEITC), found naturally in cruciferous vegetables, induced growth arrest and apoptosis in prostate cancer cells in culture and xenografts. The effects of PEITC to reactivate GSTP1 were investigated. Exposure of prostate cancer LNCaP cells to PEITC inhibited the activity and level of histone deacetylases (HDACs), and induced selective histone acetylation and methylation for chromatin unfolding. Concurrently PEITC demethylated the promoter and restored the unmethylated GSTP1 in both androgen-dependent and -independent LNCaP cancer cells to the level found in normal prostatic cells, as quantified by methylation-specific PCR and pyrosequencing. The dual action of PEITC on both the DNA and chromatin was more effective than 5'-Aza-2'-deoxycytidine, sodium butyrate, or trichostatin A (TSA), and may de-repress the methyl-binding domain (MBD) on gene transcription. The PEITC-mediated cross-talk between the DNA and chromatin in demethylating and reactivating GSTP1 genes, which is critically inactivated in prostate carcinogenesis, underlines a primary mechanism of cancer chemoprevention. Consequently, new approaches could be developed, with isothiocyanates to prevent and inhibit malignancies.

Development of a fast scanning miniature probe and methods of dispersion management for high-resolution optical coherence tomography

We present a design of a miniature fiber-optic probe capable of rapid lateral scanning. The miniature probe permits forward-looking optical coherence tomography (OCT) imaging of internal organs in real time. Fast lateral scanning also enables a new real-time image acquisition sequence, potentially permitting real-time focus tracking. To perform sensitive heterodyne detection, a sufficient Doppler frequency is achieved by using an electro-optic (EO) phase modulator. In this paper we describe an effective approach to compensate the dispersion induced by the EO crystal up to the third order. We show that an optimal axial resolution offered by the light source can be recovered through the dispersion management. Preliminary results of real-time OCT imaging of biological tissues with the lateral-priority scanning probe are presented.