The 'D-M-C' strategy for conventional ameloblastoma of the mandible: a retrospective study

The purpose of this multicentre study was to evaluate the efficacy of the 'dredging-marsupialization-curettage' (D-M-C) strategy in the treatment of conventional intraosseous ameloblastoma of the mandible. A total of 31 patients from three institutions, who had a pathological diagnosis of conventional ameloblastoma of the mandible, were treated with the D-M-C strategy. The surgical protocol comprised a dredging and marsupialization (D-M) step, with additional D-M steps as required. The patients then underwent curettage (C) once an obvious effect of the D-M step had been achieved during follow-up. Eight patients were followed up for ≥36 months but <60 months, while 23 were followed up for ≥60 months. Nineteen of the 23 patients followed up for ≥60 months were disease-free at the last follow-up, with no evidence of recurrence. The D-M step is effective for reducing the tumour size and preserving vital structures. The D-M-C surgical strategy may be a feasible treatment option for conventional ameloblastoma of the mandible.

The identification of a correlation between lipid content in the model diatom Phaeodactylum tricornutum and pH treatment strategies

pH treatment promotes single-cell lipid accumulation and significantly affects microalgae growth. This study investigates the correlation between lipid content and environmental pH using the model diatom Phaeodactylum tricornutum (P. tricornutum). We compared three distinct pH treatment strategies-continuous, intermittent, and a two-phase culture-in P. tricornutum. Rigorous analysis of chlorophyll content, cell density, and lipid content indicated that ongoing pH treatment at pH 9.5 (CHES) emerged as the most effective approach for lipid accumulation in P. tricornutum. The CHES buffer treatment significantly boosted total lipid yield and led to a reduction in protein content. Carbohydrate content experienced a slight decline under CHES buffer treatment, but changes were observed in the activities of key enzymes. Specifically, [acyl-carrier-protein] S-malonyltransferase (MAT) activity decreased after 3 days in the control treatment, while no significant change was noted under the CHES buffer treatment. In contrast, diacylglycerol O-acyltransferase (DGAT) activity showed upregulation 2 and 3 days post-CHES buffer treatment. Moreover, the study identified differentially expressed genes enriched in Gene Ontology (GO) terms associated with protein biosynthesis, photosynthesis, nucleoside metabolism, and transferase activity. These outcomes underscore the pivotal role of CHES buffer in orchestrating primary metabolism, potentially steering carbon flux towards lipogenesis. As a result, the potential of microalgae as a sustainable source of biofuels contributes significantly to the transition towards a more environmentally friendly energy landscape.

Rapid granulation of aerobic granular sludge and maintaining its stability by combining the effects of multi-ionic matrix and bio-carrier in a continuous-flow membrane bioreactor

The present investigation aimed at providing a novel approach to promote the rapid granulation and stability of aerobic granular sludge (AGS) in a continuous-flow membrane bioreactor (MBR). By operating two identical MBRs with or with no bio-carrier for 125 days, it was found that the combination of multi-ionic matrix and bio-carrier could promote the rapid formation and maintain the long-term stability of AGS. The primary AGS was first observed inside the reactor on day 14, and the mature AGS appeared soon and kept stable for more than 4 months (its average size still was about 800 μm on day 125). Suitable filling ratio of bio-carrier was beneficial to form a stable and regular circulating water flow inside, and adding divalent metal ions quickly reduced the negative charges of tiny sludge particles, which were two essential factors leading to the rapid granulation of AGS and maintaining its stability. The multi-ionic matrix not only enhanced the biological aggregation process, but also facilitated the expansion of the cultivated AGS into a new multi-habitat system of Mn-AGS, in which, complex microbial communities with rich bio-diversity robustly promoted the efficient removal of organic pollutants and nutrients.

Insights into the fouling layer of flat-sheet membrane and its development in an integrated oxidation ditch-membrane bioreactor

This work revealed the characteristics of fouling layer on the flat-sheet membranes and its development in an integrated oxidation-ditch membrane bioreactor. During the operation period (130 days), the reactor performed very well in removing pollutants. As the operation proceeded, membrane fouling occurred on the flat-sheet membranes and trans-membrane pressure showed a cyclical variation. The experimental results showed that the process of membrane fouling appeared successively in two different structures: biofilm (BF) and sludge fouling (SF). The substances causing membrane fouling were mainly organic foulants and a small amount of inorganic metal compounds, especially the protein-like and fulvic acid-like substances in loosely bound extracellular polymeric substances (LB-EPS). The analysis of microbial communities revealed that SF and BF had very different microbial properties. Although most membrane foulants could be removed by physical and chemical cleaning methods, the protein-like and fulvic acid-like substances in BF were contribute much to causing irreversible membrane fouling.

[Value of purple sign for predicting rebleeding events in cirrhotic patients following endoscopic selective varices devascularization]

OBJECTIVE

To assess the value of the purple sign for predicting long-term rebleeding events in cirrhotic patients following endoscopic selective varices devascularization.

METHODS

We retrospectively analyzed the clinical data of 97 patients with liver cirrhosis, who had a history of gastroesophageal variceal bleeding and underwent endoscopic selective varices devascularization. Thirty-two of the patients showed purple sign after endoscopic treatment. We used propensity score matching (PSM) to minimize the selection bias of the patients (purple sign vs no purple sign) and reduce the intergroup differences of clinical characteristics. The primary outcome measure of this study was cumulative rebleeding events after endoscopic selective varices devascularization.

RESULTS

The 1-year rebleeding rate (27.0% vs 36.7%) or 6-month rebleeding rate (10.9% vs 26.9%) following endoscopic treatment was not significantly different between the purple sign group and no purple sign group before PSM (P=0.2385). But after PSM, the 1-year rebleeding rate (28.2% vs 56.4%) and 6-month rebleeding rate (5.0% vs 37.0%) were significantly lower in the purple sign group than in the no purple sign group (P=0.0304).

CONCLUSIONS

The presence of purple sign indicates a lower risk of rebleeding after endoscopic treatment of cirrhotic gastroesophageal varices and a potentially favorable treatment response after endoscopic therapy, thus providing a clinical indicator for stratification of the patients for sequential endoscopic sessions.

A gulose moiety contributes to the belomycin (BLM) disaccharide selective targeting to lung cancer cells

Eight mono- or disaccharide analogues derived from BLM disaccharide, along with the corresponding carbohydate-dye conjugates have been designed and synthesized in this study, aiming at exploring the effect of a gulose residue on the cellular binding/uptake of BLM disaccharide and it possible uptake mechanism. Our evidence is presented indicating that, for the cellular binding/uptake of BLM disaccharide, a gulose residue is an essential subunit but unrelated to its chemical nature. Interestingly, d-gulose-dye conjugate is able to selectively target A549 cancer cells, but l-gulose-dye conjugate fails. Further uptake mechanism studies demonstrate d-gulose-dye derivatives similar to BLM disaccharide-dye ones behave in a temperature- and ATP-dependent manner, and are partly directed by the GLUT1 receptor. Moreover, d-gulose modifying gemcitabine 53a exhibits more potent antitumor activity compared to derivatives 53b-c in which gemcitabine is decorated with other monosaccharides. Taken together, the monosacharide d-gulose conjugate offers a new strategy for solving cytotoxic drugs via the increased tumor targeting in the therapy of lung cancer.

In situ small-angle X-ray scattering studies during the formation of polymer/silica nanocomposite particles in aqueous solution

This study is focused on the formation of polymer/silica nanocomposite particles prepared by the surfactant-free aqueous emulsion polymerization of 2,2,2-trifluoroethyl methacrylate (TFEMA) in the presence of 19 nm glycerol-functionalized aqueous silica nanoparticles using a cationic azo initiator at 60 °C. The TFEMA polymerization kinetics are monitored using 1H NMR spectroscopy, while postmortem TEM analysis confirms that the final nanocomposite particles possess a well-defined core-shell morphology. Time-resolved small-angle X-ray scattering (SAXS) is used in conjunction with a stirrable reaction cell to monitor the evolution of the nanocomposite particle diameter, mean silica shell thickness, mean number of silica nanoparticles within the shell, silica aggregation efficiency and packing density during the TFEMA polymerization. Nucleation occurs after 10-15 min and the nascent particles quickly become swollen with TFEMA monomer, which leads to a relatively fast rate of polymerization. Additional surface area is created as these initial particles grow and anionic silica nanoparticles adsorb at the particle surface to maintain a relatively high surface coverage and hence ensure colloidal stability. At high TFEMA conversion, a contiguous silica shell is formed and essentially no further adsorption of silica nanoparticles occurs. A population balance model is introduced into the SAXS model to account for the gradual incorporation of the silica nanoparticles within the nanocomposite particles. The final PTFEMA/silica nanocomposite particles are obtained at 96% TFEMA conversion after 140 min, have a volume-average diameter of 216 ± 9 nm and contain approximately 274 silica nanoparticles within their outer shells; a silica aggregation efficiency of 75% can be achieved for such formulations.

Characterization of bacteriophage HN48 and its protective effects in Nile tilapia Oreochromis niloticus against Streptococcus agalactiae infections

Streptococcus agalactiae is a causative agent responsible for massive mortalities of tilapia that has led to catastrophic losses to tilapia culture globally. Bacteriophages represent a new class of antimicrobials against bacteria. In this study, we characterized the bacteriophage HN48, which formed small and round-transparent plaques on a double-layer plate. With a hexagonal head and a long tail, this phage may belong to the Caudovirales according to the International Committee on Taxonomy of Viruses. HN48 was found to have a relatively wide and highly specific host range, to be sensitive to high temperature (60-80°C) and low pH (3-5), and to be relatively stable at alkaline pH (8-10). Intraperitoneal injection with HN48 had no adverse effects on tilapia and effectively inactivated the bacteria in the kidney. Fish that received phage therapy had 60% ± 3.3% survival rates and a delayed mean death time of about 3 days when compared to the control group. To the best of knowledge, this is the first study of tilapia streptococcal phage. Overall, the results indicated that phage HN48 could prevent tilapia from experimental S. agalactiae infection, suggesting it has the potential to control this disease.

Dual Ion Species Plasma Expansion from Isotopically Layered Cryogenic Targets

A dual ion species plasma expansion scheme from a novel target structure is introduced, in which a nanometer-thick layer of pure deuterium exists as a buffer species at the target-vacuum interface of a hydrogen plasma. Modeling shows that by controlling the deuterium layer thickness, a composite H^{+}/D^{+} ion beam can be produced by target normal sheath acceleration (TNSA), with an adjustable ratio of ion densities, as high energy proton acceleration is suppressed by the acceleration of a spectrally peaked deuteron beam. Particle in cell modeling shows that a (4.3±0.7)  MeV per nucleon deuteron beam is accelerated, in a directional cone of half angle 9°. Experimentally, this was investigated using state of the art cryogenic targetry and a spectrally peaked deuteron beam of (3.4±0.7)  MeV per nucleon was measured in a cone of half angle 7°-9°, while maintaining a significant TNSA proton component.

wblA, a pleiotropic regulatory gene modulating morphogenesis and daptomycin production in Streptomyces roseosporus

AIMS

The wblA gene, encoding a homologue of the WhiB family protein, was identified in the sequenced genome of daptomycin producer Streptomyces roseosporus. To explore the function of wblA, we construct wblA disruption strains, complemented strains and overexpression strains to test whether it can affect the production of secondary metabolites and morphogenesis.

METHODS AND RESULTS

We constructed disruption strains by homologous recombination in S. roseosporus. The disruption mutant of wblA could block aerial mycelium sporulation and enhance the production of daptomycin by 51%. In contrast, overexpression of wblA resulted in significantly decreased the yield of daptomycin. In agreement with it, the transcription of key daptomycin regulatory genes atrA, dptR2 and dptR3 and structural gene dptE remarkably increased in the wblA disruption mutant.

CONCLUSIONS

wblA plays a key role in control of daptomycin biosynthesis and is essential for sporulation. The disruption of wblA could accumulate the transcription level of some key genes involving in daptomycin biosynthesis.

SIGNIFICANCE AND IMPACT OF THE STUDY

Daptomycin is an important antibiotic with potent activity against a variety of Gram-positive pathogens. This study demonstrates that valuable improvement in the yield of daptomycin can be achieved through modulating the expression of wblA transcription regulator.

Enteral versus parenteral nutrition in critically ill patients with severe pancreatitis: a meta-analysis

Whether enteral nutrition (EN) is superior to parenteral nutrition (PN) in critically ill patients with severe acute pancreatitis remains unknown. The objective of this meta-analysis was to assess the effects of EN versus PN on clinical outcomes in a subgroup of pancreatitis patients. Relevant randomized controlled trials (RCTs) were searched in Scopus, PubMed and Web of Science from inception to August 2016. Ultimately, five RCTs including 348 patients were enrolled in this analysis. Compared with PN, EN was associated with a significant reduction in overall mortality (risk ratio (RR)=0.36, 95% confidence interval (CI) 0.20-0.65, P=0.001) and the rate of multiple organ failure (RR=0.39, 95% CI 0.21-0.73, P=0.003). EN should be recommended as the preferred route of nutrition for critically ill patients with severe acute pancreatitis.

Influence of pelvic postural angle change on acetabulum implantation in total hip arthroplasty

The current study investigated the relationship between the implantation angle of the acetabular component and the change in the pelvic postural angle during hip arthroplasty surgery. One pelvis with a left lower limb prosthesis was used. Total hip arthroplasty on the left pelvis was simulated with the help of a computer-assisted navigation system. The pelvis revolved around the horizontal, longitudinal and sagittal axes at different angles, and the anteversion and abduction of the acetabular component were measured. The changing angle of the pelvis rotating around the horizontal and longitudinal axes greatly influenced acetabular component anteversion. The changing angle of the pelvis rotating around the sagittal axis had a relatively great influence on the acetabular component abduction angle. The change in the postural angle of the pelvis had a great influence on the installation angle of the acetabular component. It is important to standardize posture prior to the operation.

Prevalence, concentrations, and antibiotic sensitivities of Salmonella serovars in poultry from retail establishments in Seattle, Washington

Poultry have been identified as one of the major sources of salmonellosis, with estimates ranging from 10 to 22% of total cases. Despite several advances in the industry and new performance standards, the incidence of salmonellosis in the population has not declined over the last 15 years. Salmonella is pervasive in a wide variety of foods, and thus, estimating its burden resulting from specific food categories has been challenging and plagued with uncertainty due to critical data gaps. The objective of this study was to conduct a year-long market survey (1,322 samples) to help bridge the data gaps on the contamination rates and levels of Salmonella on raw poultry by product type (i.e., breast, thighs, drums, wings, and split breast) and production method (conventional versus organic). The isolates recovered were serotyped and tested for antibiotic sensitivities. A PCR method was utilized for initial screening of samples after an overnight enrichment in tryptic soy broth. Three-tube most-probable-number (MPN) assays and anti-Salmonella immunomagnetic separation methods were utilized to determine the levels of Salmonella and aid with the recovery of Salmonella species, respectively. Eleven percent of the samples were positive for Salmonella. Significant differences in percent positive rates by product type included up to a 4-fold difference in percent positive rates between establishments, ranging from 7 to 31%. Of the samples positive for Salmonella species, 94% had <30 MPN/100 g. Production methods identified as organic or as not using antibiotics had significantly higher rates of recovery of Salmonella. On the other hand, all of the Salmonella isolates that were resistant to two or more antibiotics originated from conventional processing establishments where antibiotics were utilized. In addition, a significant proportion of isolates from conventionally processed products were serotypes clinically relevant to humans.

Abstract P4-05-03: Unique genetic, epigenetic, and transcriptomic changes in premenopausal breast cancer suggest novel strategies for therapy

Breast cancer in premenopausal women (preM) is frequently associated with worse prognosis compared to that in postmenopausal women (postM) even when controlling for prognostic variables. In particular, preM ER+ tumors have a poor prognosis on endocrine therapy. There is, however, a paucity of studies characterizing molecular alterations in premenopausal tumors, a potential avenue for finding personalized therapies for this group of women.

We analyzed gene expression, CNV, methylation, and somatic mutations in tumors from preM (≤45; ER+ n = 110, and ER- n = 39) and postM (≥55, ER+ n = 392, and ER- n = 102) women in The Cancer Genome Atlas (TCGA). Unbiased hierarchical clustering of 2,900 most variably expressed genes (using both RNA-seq and Agilent expression array data) in the whole dataset (n = 643) identified four major subtypes which correlated highly with the PAM50 defined subtypes LumA, LumB, Basal and HER2; however, there wasn't any separation between preM and postM samples. Similarly, principal component analysis using 10,000 genes with the highest inter-quartile range (IQR) demonstrated high similarity across preM and postM samples. Direct examination of gene expression differences between PreM and PostM ER+ tumors using unpaired t-test (5% FDR) identified 3,044 differentially expressed genes. The genes most upregulated in premenopausal tumors included AREG, TFPI2, MSMB, TCN1, and GLRA3. Ingenuity Pathway Analysis revealed a highly significant enrichment for TGFb (p&lt;1.9E-16) pathway activity in preM tumors. Intriguingly, no significant gene expression differences between preM and postM ER- tumors were identified. We thus then focused on genetic and epigenetic alterations that may underlie these transcriptomic changes in ER+ preM tumors.

Comparison of methylation (450K Illumina array) between preM and postM ER+ tumors showed a difference in 1% (n = 1,738) of the probes. Genes with the largest difference included ESR1, SIM2, and KLF6. Significant differences in DNA copy number variation (Affymetrix SNP 6.0 array) were also identified in ER+ preM tumors. A number of somatic mutations were significantly enriched in preM ER+ tumors including DSPP and GATA3. Integrated analysis also showed that approximately half of the observed differences in gene expression are driven by CNVs.

Conclusion: Our in silico study has identified a number of genes and pathways which are significantly altered between preM and postM ER+ breast cancer. Distinct genetic and epigenetic differences suggest unique etiology for some preM tumors. Currently ongoing Paradigm analysis, and confirmatory studies using METABRIC data are expected to further identify pathways that could specifically be targeted in premenopausal breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-05-03.

Improvement of A21978C production in Streptomyces roseosporus by reporter-guided rpsL mutation selection

AIMS

Daptomycin, one of the A21978C factors produced by Streptomyces roseosporus, is an acidic cyclic lipopeptide antibiotic with potent activity against a variety of Gram-positive pathogens. To increase the titre of this extensively used and clinically important antibiotic, we applied a reported-guided rpsL mutation selection system to generate strains producing high levels of A21978C.

METHODS AND RESULTS

In the reporter design, dptE was chosen as the overexpressing target, and neo-encoding neomycin phosphotransferase as the reporter. Using this reporter-guided selection system, 20% of the selected, streptomycin-resistant mutants produced greater amounts of A21978C than the starting strain. The selection system increased the screening efficiency about 10-fold with a frequency of 1·7% A21978C overproducing strains among str(r) mutants. A21978C production was increased approximately 2·2-fold in the rpsL K43N mutant.

CONCLUSIONS

The combination of ribosome engineering and reporter-guided mutant selection generated an A21978C overproducing strain that produced about twice as much A21978C as the parental strain.

SIGNIFICANCE AND IMPACT OF THE STUDY

The strategies presented here, which integrated the advantages of both ribosome engineering and reporter-guided mutation selection, could be applied to other bacteria to improve their yield of secondary metabolites.

Association of the 54-nucleotide repeat polymorphism of hPer3 with heroin dependence in Han Chinese population

Circadian clock genes have the function of producing circadian rhythm. They are also implicated in the origin or development of many diseases such as cancers and neuropsychiatric diseases. The purpose of this study is to determine whether the 54-nucleotide repeat polymorphism of hPer3, one of the circadian clock genes, associates with heroin dependence. DNA samples were obtained from 209 Chinese heroin-dependent subjects and 249 Chinese healthy controls. The 54-nucleotide repeat polymorphism was detected by polymerase chain reaction and DNA agarose gel electrophoresis. The frequency of four-repeat allele was significantly higher (chi(2)= 10.64, P = 0.001; corrected for multiple tests, P = 0.003) in the mixed gender heroin-dependent subject group (four repeat: 0.89, five repeat: 0.11) than in the mixed gender control group (four repeat: 0.81, five repeat: 0.19); the frequency of four-repeat allele was also significantly higher (chi(2)= 10.00, P = 0.002; corrected for multiple tests, P = 0.006) in the male heroin-dependent subject group (four repeat: 0.89, five repeat: 0.11) than in the male control group (four repeat: 0.81, five repeat: 0.19); for females, no significant trend was observed with the 54-nucleotide repeat polymorphism between the heroin-dependent subject group and the control group. Our results suggest that the 54-nucleotide repeat polymorphism of hPer3 significantly associates with heroin dependence at the allele frequency level and may be a potential risk factor for the development of heroin dependence.

Chirality and polarity transfers between bent-core smectic liquid-crystal substances

Liquid-crystal phases with both solid and liquid characteristics are unique, since they exhibit chirality on both molecular and mesoscopic levels under special circumstances. We have studied binary composites formed by mixing of a chiral dimer (B-Ch), in which a bent core is covalently linked to a promesogenic cholesterol unit through a flexible spacer, and an achiral bent-core mesogen having two vicinal fluorine atoms (B-2F). The pure materials show smectic phases featuring C2 symmetry. The dimer B-Ch displays conventional chiral smectic C (SmC*) phase with a chirality--induced polarization P(c) approximately 30 nC/cm2, whereas B-2F possesses synclinic and anticlinic antiferroelectric "banana" smectic (SmCP) phase with a relatively high-polarization (P(b)) value of about 900 nC/cm(2). Mixing these two materials we were able to measure P(c), and we have verified that the molecular chirality contributes to the polarization of banana phases only in synclinic configurations.

Ferroelectricity of a bent-core material with cholesteryl terminal chain

We have studied the phase sequence and physical properties of an asymmetric bent-core material with a chiral rigid cholesteryl moiety, and a flexible achiral alkyl side chain at the other end. The combination of the achiral bent core with the chiral cholesteryl unit results in properties different from those of both the usual calamitic and bent-core materials. We find that the presence of the bent core unit induces a wide-temperature-range optically isotropic (probably BPIII) mesophase between the isotropic and cholesteric (chiral nematic) phases. Below the cholesteric phase a ferroelectric smectic-C* structure occurs in which the bent-core units do not seem to form a polar close packing.

Breast cancer resistance protein-mediated topotecan resistance in ovarian cancer cells

Overexpression of breast cancer resistance protein (BCRP) and mitoxantrone (MX) resistance protein can confer resistance to a variety of cytostatic drugs, such as MX, topotecan (TPT), doxorubicin, and daunorubicin. This study investigates the role of BCRP in resistance of ovarian cancer to TPT treatment. We have developed TPT-resistant human ovarian cancer cell line. Intracellular concentration of fluorescent dye rhodamine 123 (Rh123) was measured by flow cytometry. The expression of several membrane transporter proteins including P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), and BCRP were determined by reverse transcription-polymerase chain reaction and Western blotting. The Rh123 concentration in parental cells was approximately three times of those in TPT-resistant cells. In contrast to undetectable level of P-gp messenger RNA (mRNA) and minimal level of MRP1 expression in TPT-resistant cells, overexpression of both the BCRP mRNA and the protein was detected in these cells. Introduction of antisense-phosphorothioate oligonucleotide derived from BCRP mRNA into TPT-resistant cells resulted in a significant increase in the concentration of intracellular Rh123. These results suggested a novel mechanism in which a reduced intracellular drug concentration may be mediated by BCRP gene products in human ovarian cancer cells.

A quantitative evaluation of peroxidase inhibitors for tyramide signal amplification mediated cytochemistry and histochemistry

Many peroxidase inhibitors have been used in horseradish peroxidase (HRP) mediated immunostaining and in situ hybridization to quench background peroxidase activity. However, the efficacy of these inhibitors has been controversial, partially due to the lack of a quantitative study. Tyramide signal amplification (TSA) is much more sensitive than other HRP-mediated methods but its super-sensitivity also demands effective inhibition of background peroxidase activity. In searching for an effective peroxidase inhibitor, we have systematically evaluated the efficacy of several peroxidase inhibitors by quantifying the fluorescence intensity in cultured fibroblasts and tissue sections treated with the inhibitors. For cultured cells, 0.05 mM of phenylhydrazine and 1 unit/ml of glucose oxidase gave only moderate inhibition of HRP activity while 1 mM of sodium azide (NaN(3)), 3% of hydrogen peroxide (H(2)O(2)), NaN(3)/H(2)O(2) combined and 0.02 N hydrochloric acid (HCl) provided more complete inhibition. However, the inhibitory effect of NaN(3)/H(2)O(2) is reversible upon removal of the inhibitors and followed by incubation and wash to mimic antibody interactions. Similar results were obtained from rat skin wound tissues that have strong endogenous peroxidase activity. Our results recommend the use of HCl and caution the use of phenylhydrazine, glucose oxidase, NaN(3) and H(2)O(2) as potent peroxidase inhibitors.

Electrorotation of colloidal particles in liquid crystals

We present the first observations of dc electric-field-induced rotational motion of finite particles in liquid crystals. We show that the electrorotation is essentially identical to the well-known Quincke rotation, which in liquid crystals triggers an additional translational motion at higher fields. In the smectic phase the translational motion is confined to the two-dimensional geometry of smectic layers, in contrast to the isotropic and nematic phases, where the particles can move in all three dimensions. We demonstrate that by a proper analysis of the electrorotation, one can determine the in-plane viscosity of smectic liquid crystals. This method needs only a small amount of material, does not require uniform alignment over large areas, and enables probing rheological properties locally.

Optically isotropic liquid-crystal phase of bent-core molecules with polar nanostructure

We found that the optically isotropic (I(M)) mesophase observed recently below the nematic phase of the bent-core liquid crystal 4-chlororesorcinol bis[4-(4-n-dodecyloxybenzoyloxy)benzoate] shows ferroelectric-type switching. Polarizing microscopic, electric current, dielectric, and dynamic light scattering studies lead us to propose that the I(M) phase is composed of interconnected orthoconic racemic smectic (Sm-Ca P(F)) nanodomains with random layer orientations. Near the nematic phase, where the polarization can be saturated by electric fields, the system responds in a fashion analogous to the granular structure of a magnetic spin glass--in particular, we observed that the relaxation back to the nonpoled structure follows a similar, inverse logarithmic rule.

Light-induced changes of optical and electrical properties in bent-core azo compounds

We have studied the optical and electrical properties of two bent-core substances with an azo linkage in their cores. Pump-probe laser studies, direct textural observations, and spectrophotometric recordings show an initial decrease of light transmission, which at larger light intensities (approximately 1 mW/mm2) is followed by a bleaching. Simultaneously the electrical properties (electric conductivity, antiferroelectric polarization, switching threshold, and switching time) decreased monotonically with increasing light intensities. The monotonic decrease of electrical properties indicates that the darkening and bleaching have the same origin, namely, the photochemical isomerization of the azo linkage from the trans to the cis isomer. The material with cis isomer has a lower clearing point and phase separates from the trans-rich domains. Initially the size of the separated isotropic domains is below the visible range, which causes increased scattering. As the size of the isotropic domains increase the scattering disappears and the transmittance becomes the average of the transmittances in the polar tilted smectic and isotropic phases.

Properties of two EBV Mta nuclear export signal sequences

The Epstein-Barr virus (EBV) Mta protein is a posttranscriptional regulator of EBV lytic gene expression that affects RNA splicing and transport. Mta mediates cytoplasmic accumulation of unspliced EBV replication gene transcripts and shuttles between the nucleus and cytoplasm. Mta contains a recognized leucine-rich, putative nuclear export signal (NES) between aa 227 and 236. Deletion of this signal sequence eliminated shuttling, while mutation of the core LXL motif in the putative NES diminished but did not abolish the ability of Mta to shuttle from donor to recipient cells in a heterokaryon assay. A double mutation of the LXL motif plus an upstream VTL motif eliminated shuttling, suggesting that Mta may have two NES motifs. In confirmation of this, transfer of either the sequence encoding the leucine-rich aa 227-236 motif or that encoding the adjacent hydrophobic aa 218-227 sequence to a GFP-NLS-pyruvate kinase reporter protein conferred the property of cytoplasmic accumulation onto the heterologous protein. Cytoplasmic accumulation of both the aa 225-237 and 218-227 containing reporters was minimal in the presence of the inhibitor leptomycin B, indicating that both motifs mediated Crm-1-dependent export. Mutations in the NES signal sequences abolished the ability of Mta to mediate cytoplasmic accumulation of BALF2 replication gene transcripts. This included mutation of the LXL motif which still showed cytoplasmic shuttling, suggesting that the NES mutations might have additional effects on Mta function. Wild-type Mta co-immunoprecipitated with the splicing factor SC35 and colocalized with SC35 in transfected cells, modifying endogenous SC35 distribution within the nucleus to give more intense, rounded spots. Interestingly, the NES mutant proteins appeared to have altered interactions with the splicing complex, binding more tightly to SC35 in co-immunoprecipitation assays. These observations suggest a linkage between the splicing and export functions of Mta.

Interaction with the Epstein-Barr virus helicase targets Zta to DNA replication compartments

Zta has a dual role in the Epstein-Barr virus (EBV) lytic cycle, acting as a key regulator of EBV lytic gene expression and also being essential for lytic viral DNA replication. Zta's replication function is mediated in part through interactions with the core viral replication proteins. We now show interaction between Zta and the helicase (BBLF4) and map the binding region to within amino acids (aa) 22 to 86 of the Zta activation domain. In immunofluorescence assays, green fluorescent protein (GFP)-tagged BBLF4 localized to the cytoplasm of transfected cells. Cotransfection of Zta resulted in translocation of BBLF4-GFP into the nucleus indicating interaction between these two proteins. However, Zta with a deletion of aa 24 to 86 was unable to mediate nuclear translocation of BBLF4-GFP. Results obtained with Zta variants carrying deletions across the aa 24 to 86 region indicated more than one contact site for BBLF4 within this domain, and this was reinforced by the behavior of the four-point mutant Zta (m22/26,74/75), which was severely impaired for BBLF4 interaction. Binding of BBLF4 to Zta was confirmed using GST affinity assays. In both cotransfection-replication assays and replication assays performed in EBV-positive P3HR1 cells, the Zta (m22/26,74/75) mutant was replication defective. In Zta-transfected D98-HR1 cells, replication compartments could be detected by immunofluorescence staining using anti-BMRF1 monoclonal antibody. Cells transfected with Zta variants that were defective for helicase binding still formed replication compartments, but Zta was excluded from these compartments. These experiments reveal a role for the Zta-helicase interaction in targeting Zta to sites of viral DNA replication.

Pneumatic lithotripsy versus laser lithotripsy in the endoscopic treatment of ureteral calculi

PURPOSE

To compare the efficacy, safety, and features of pneumatic lithotripsy (PL) with those of laser lithotripsy (LL) and present our clinical experience in the endoscopic management of ureteral calculi.

PATIENTS AND METHODS

From August 1994 to February 2000, 285 consecutive patients underwent endoscopic lithotripsy with either the Swiss Lithoclast pneumatic lithotripter (145 patients) or the Ho:YAG laser lithotripter (140 patients) for the treatment of ureteral calculi.

RESULTS

In one single session, the overall successful stone fragmentation rate of LL was higher than that of PL (95.7% v 69.7%; P < 0.01). The average time to stone-free status was shorter for LL than for PL (18 days v 31 days; P < 0.01). No major complications were observed in LL, while five ureteral perforations were encountered in PL.

CONCLUSIONS

Laser lithotripsy has advantages over PL in high efficiency of stone fragmentation and a low complication rate. Laser lithotripsy is a powerful, effective, and safe treatment modality for ureteral calculi.

Human herpesvirus 8 LANA interacts with proteins of the mSin3 corepressor complex and negatively regulates Epstein-Barr virus gene expression in dually infected PEL cells

The human herpesvirus 8 (HHV-8) latency-associated nuclear antigen (LANA) is expressed in all latently HHV-8 infected cells and in HHV-8-associated tumors, including primary effusion lymphoma (PEL). To better understand the contribution of LANA to tumorigenesis and to the PEL phenotype, we performed a yeast two-hybrid screen which identified the corepressor protein SAP30 as a LANA binding protein. SAP30 is a constituent of a large multicomponent complex that brings histone deacetylases to the promoter. Glutathione S-transferase affinity assays confirmed interaction between LANA and SAP30 and also demonstrated interactions between LANA and two other members of the corepressor complex, mSin3A and CIR. The corepressors bound to the amino-terminal 340-amino-acid domain of LANA. In transient expression assays, this same domain of LANA mediated repression when targeted to a 5xGal4tk-CAT reporter as a GAL4-LANA fusion. PEL cells have the unusual feature that they are frequently dually infected with both HHV-8 and Epstein-Barr virus (EBV). We found that EBV EBNA-1 expression is downregulated in PEL cells at both the RNA and protein levels. In transient expression assays, LANA repressed activated expression from the EBV Qp and Cp latency promoters. Reduction of endogenous Qp activity could also be demonstrated in EBV-infected Rael cells transfected with a LANA expression plasmid. In contrast to the effect of LANA on EBV latency promoters, LANA activated expression from its own promoter. The data indicate that LANA can mediate transcriptional repression through recruitment of an mSin3 corepressor complex and further that LANA-mediated repression is likely to contribute to the low level of EBV latency gene expression seen in dually infected PEL cells.

[DNA damage and c-myc gene expression of NIH3T3 cell induced by superoxide anion]

OBJECTIVE

To study the DNA damage, membrane lipid peroxidation, and c-myc gene expression of NIH3T3 cell induced by superoxide anion(O2.-).

METHODS

The superoxide anion(O2.-) was produced by reactive system of xanthine-xanthine oxidase (X-XO) and the DNA-EB complex, malondialdehyde (MDA) content and expression of c-myc gene were measured by means of fluorescence, thiobarbituric acid (TBA) assay and DNA-RNA situ hybridization with digoxigenin labeled probes respectively.

RESULTS

The O2.- of high concentration(X: 20 micrograms, XO: 2 x 10(-3) U) reacted with isolated DNA from NIH3T3 cell directly which caused DNA damage obviously. When the O2.- of high concentration reacted with whole NIH3T3 cell, the amount of MDA increased and fluorescence intensity of DNA-EB complex decreased which mean lipid peroxidation of membrane and gene damage of the cell respectively. When the producing O2.- of high concentration reactive system existing FeSO4, the phenomena mentioned above showed obviously. Enough amount of catalase showed the inhibit effects, but it could not completely inhibit the DNA damage of whole cell. The c-myc gene expression was observed in the cell treated with O2.- of middle (X: 4 micrograms, XO: 4 x 10(-4) U) and high concentration, but it was not observed in the cell treated with O2.- of low concentration(X: 0.4 micrograms, XO: 4 x 10(-5) U).

CONCLUSIONS

DNA damage of the whole cell induced by extracellular O2.- was able to act through the pathway of membrane lipid peroxidation in which hydrogen peroxide is important and the other pathways such as signal transduction of the cell might also be existed. The expression of c-myc gene of NIH3T3 cell induced by O2.- was related closely to the concentration of O2.-.

[Study on the role of superoxide anion in promoting proliferation and transformation of rat liver oval cell line WB-E344]

OBJECTIVE

To study the role of superoxide anion (O2.-) in promoting proliferation and transformation of rat liver oval cell strain WB-F344.

METHODS

WB-F344 cells cultured were stimulated directly by O2.- generated by interaction of xanthine with xanthine oxidase (X-XO). The effect of O2.- in promoting proliferation of WB cells was investigated by using MTT colorimetric analysis, 3H-Tdr incorporation liquid scintillation counter and 3H-Tdr incorporation autoradiography. WB cells initiated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) were promoted by stimulating continuously with O2.- of low concentration (X: 100 mumol/L, XO: 0.2 mU/ml). The transformation effect was tested by morphologic observation, karyotype analysis and anchorage-independent growth assay.

RESULTS

Proliferation of WB cells was induced obviously by O2.- of low concentration for only one time. WB cells initiated with MNNG were transformed by action with O2.- of low concentration continuously for 15 d and typical morphologic character of transformed cells was observed. In karyotype analysis the cells chromosome number changed and the frequency of structure aberration raised dramatically. Also the transformed cells could form clone on self-solid culture medium.

CONCLUSIONS

The biological effect of O2.- was related closely with its dose; The effects of low concentration in promoting proliferation and transformation of liver oval cells indicate its important role in hepatocarcinogenesis and antioxidation was able to provide a new clue in prevention and cure of hepatoma.

Small-angle x-ray scattering study of kinetics of spinodal decomposition in N-isopropylacrylamide gels

We present synchrotron-based time-resolved small-angle x-ray scattering (SAXS) measurements of spinodal decomposition in a covalently cross-linked N-isopropylacrylamide gel. The range of wave numbers examined is well beyond the position of the maximum in the structure factor S(q,t). The equilibrium structure factor is described by the sum of a Lorentzian and a Gaussian. Following a temperature jump into the two phase region, the scattered intensity increases with time and eventually saturates. For early times the linear Cahn-Hilliard-Cook (CHC) theory can be used to describe the time evolution of the scattered intensity. From this analysis we found that the growth rate R(q) is linearly dependent on q(2), in agreement with mean-field theoretical predictions. However the Onsager transport coefficient Lambda(q) approximately q(-4), which is stronger than the q dependence predicted by the mean-field theory. We found that the growth rate R(q)>0, even though the wave numbers q probed by SAXS are greater than sqrt[2]q(m) where q(m) is the position of the peak of S(q,t), also in agreement with the mean-field predictions for a deep quench. We have also examined the range of validity of the linear CHC theory, and found that its breakdown occurs earlier at higher wave numbers. At later times, a pinning of the structure was observed. The relaxation to a final, microphase-separated morphology is faster and occurs earlier at the highest wave numbers, which probe length scales comparable to the average distance between crosslinks.

[Study on the pharmacokinetics of the liver targeted mitoxantrone polylactic acid extended-release nanoparticles in rabbits]

HPLC was used to analyse the drug concentrations in blood. The 3p87 (practical pharmacokinetic program-version) was used to calculate the parameters of DHAQ-PLA-NP lyophilization injection and DHAQ injection through i.v. administration in rabbit blood. The concentration-time curves of the two kinds of preparations were in keeping with the three-compartment model. The drug concentrations were calculated according to the selecting pharmaceutical model and parameters. The calculated drug concentrations agreed well with the observed. The lyophilization injection sustained the eliminating process in vivo.

[The in vitro release kinetics of Daunorubicin polybutylcyanoacrylate nanoparticles]

The in vitro release kinetics of Daunorubicin Polybutylcyanoacrylate Nanoparticles(DNR-PBCA-NP) was studied by dynamic dialysis system. The concentration of Daunorubicin was determined by spectrophotometry. The result showed the in vitro release kinetics of DNR-PBCA-NP could be well characterized by a biexponential equation. There were two phases in the process of drug release. The initial phase was a fast release phase (the burst effect). The second phase was a slow release phase.

Detyrosination of tubulin regulates the interaction of intermediate filaments with microtubules in vivo via a kinesin-dependent mechanism

Posttranslationally modified forms of tubulin accumulate in the subset of stabilized microtubules (MTs) in cells but are not themselves involved in generating MT stability. We showed previously that stabilized, detyrosinated (Glu) MTs function to localize vimentin intermediate filaments (IFs) in fibroblasts. To determine whether tubulin detyrosination or MT stability is the critical element in the preferential association of IFs with Glu MTs, we microinjected nonpolymerizable Glu tubulin into cells. If detyrosination is critical, then soluble Glu tubulin should be a competitive inhibitor of the IF-MT interaction. Before microinjection, Glu tubulin was rendered nonpolymerizable and nontyrosinatable by treatment with iodoacetamide (IAA). Microinjected IAA-Glu tubulin disrupted the interaction of IFs with MTs, as assayed by the collapse of IFs to a perinuclear location, and had no detectable effect on the array of Glu or tyrosinated MTs in cells. Conversely, neither IAA-tyrosinated tubulin nor untreated Glu tubulin, which assembled into MTs, caused collapse of IFs when microinjected. The epitope on Glu tubulin responsible for interfering with the Glu MT-IF interaction was mapped by microinjecting tubulin fragments of alpha-tubulin. The 14-kDa C-terminal fragment of Glu tubulin (alpha-C Glu) induced IF collapse, whereas the 36-kDa N-terminal fragment of alpha-tubulin did not alter the IF array. The epitope required more than the detyrosination site at the C terminus, because a short peptide (a 7-mer) mimicking the C terminus of Glu tubulin did not disrupt the IF distribution. We previously showed that kinesin may mediate the interaction of Glu MTs and IFs. In this study we found that kinesin binding to MTs in vitro was inhibited by the same reagents (i.e., IAA-Glu tubulin and alpha-C Glu) that disrupted the IF-Glu MT interaction in vivo. These results demonstrate for the first time that tubulin detyrosination functions as a signal for the recruitment of IFs to MTs via a mechanism that is likely to involve kinesin.

[Inhibition effects of tumor infiltrating lymphocytes from oral cancer on nude mice transplanted tumor established with human tongue carcinoma cell lines]

OBJECTIVE

To observe the in vivo inhibition effects on nude mice transplanted tumor with tumor infiltrating lymphocytes (TILs) isolated from primary mass of oral cancer.

METHODS

Established the transplanted tumor model of human tongue cancer at the back of BALB/C nude mice with subcutaneous injection of squamous cell carcinoma lines Tca 8113. TILs isolated from patients with Oral cancer, combining with low dose of cyclophosphamide (Cy: 50 mg/kg), were locally injected into the peripheral site of tumor. The inhibition rate (IR) was calculated by the volume of tumor mass from the 1st to the 8th week, and the weights at the 8th week after tumor dissection.

RESULTS

1. Group TIL + rIL-2 and group TIL + rIL-2 + Cy both exerted a strong inhibition effect on the transplanted tumor within three weeks. The Inhibition rate (IR) were 86.1% +/- 0.4% and 97.7% +/- 0.6% respectively at the 3rd week, while 32.1% +/- 0.3% and 80.6% +/- 0.3% at the 8th week. 2. TIL + rIL-2 + Cy expressed a stronger effect and a longer inhibition time. The IR of TIL + rIL-2 and TIL + rIL-2 + Cy were 20.0% +/- 1.4% and 75.5% +/- 2.5% respeetively at the 8th week (P < 0.01).

CONCLUSION

This study demonstrated that TILs from patients with oral carcer possess strong in vivo inhibition on nude mice transplanted tumor, and low dose of cyclophasophamide can enhance the inhibition effect and prolong the inhibition time.

Kinesin is a candidate for cross-bridging microtubules and intermediate filaments. Selective binding of kinesin to detyrosinated tubulin and vimentin

We showed previously that stable, detyrosinated (Glu) microtubules function to localize vimentin intermediate filaments in fibroblasts (Gurland, G., and Gundersen, G. G. (1995) J. Cell Biol. 131, 1275-1290). To identify candidate proteins that mediate the Glu microtubule-vimentin interaction, we incubated microtubules with microtubule-interacting proteins and saturating levels of antibodies to Glu or tyrosinated (Tyr) tubulin. Antibodies to Glu tubulin prevented the microtubule binding of kinesin obtained from fibroblast or brain extracts more effectively than antibodies to Tyr tubulin. Scatchard plot analysis showed that kinesin heads bound to Glu microtubules with an approximately 2.8-fold higher affinity than to Tyr microtubules. Purified brain kinesin cosedimented with vimentin, but not with neurofilaments, indicating that kinesin specifically associates with vimentin without accessory molecules. Kinesin binding to vimentin was not sensitive to ATP, and kinesin heads failed to bind to vimentin. By SDS-polyacrylamide gel electrophoresis, a kinesin heavy chain of approximately 120 kDa and a light chain of approximately 64 kDa were detected in vimentin/kinesin pellets. The light chain reacted with a general kinesin light chain antibody, but not with two other antibodies that recognize the two known isoforms of kinesin light chain in brain, suggesting that the kinesin involved in binding to vimentin may be a specific one. These results demonstrate a kinesin-based mechanism for the preferential interaction of vimentin with detyrosinated microtubules.

[Relationship between oval cells and preneoplastic lesions induced by 2-acetylaminofluorene in rat liver]

OBJECTIVE

To study the cellular origin of preneoplastic lesion of liver induced by the 2-acetylaminofluorene (2-AAF) in rat.

METHODS

Male fisher 344 rats were used for two different carcinogenesis models. Model 1: Rats were fed with regular diet containing 0.02% 2-AAF for totally 28 days, and subjected to a standard two thirds partial hepatectomy (2/3 PH) on the 7th day in order to stimulate the proliferation of oval cells. 3H thymidine (3H-Tdr) was administered intraperitoneally on the 12th day for selective labelling of oval cells. Model II: Rats were subjected to 2/3 PH and 3H-Tdr was administered intraperitoneally 22 hours after the operation for the selective labelling of hepatocytes. The rats were then fed with 2-AAF for totally 28 days after a 9 days recovery period from 2/3 PH. The relationship between preneoplastic lesion and selectively labelled oval cells, or hepatocytes, was traced by autoradiography.

RESULTS

Pathological examination and autoradiography denoted that the silver grains (labelled signals) were only formed in the preneoplastic cells in model I rather than the cells of model II animals.

CONCLUSION

It is a direct evidence to demonstrate that the preneoplastic cells are mostly originated from the oval cells.

[Reliability design and analysis of man-machine performance of display and illumination system in cockpit]

This paper analysed and discussed the basic reliability of display and illumination system in which Chinese characters displayed on LCD were read and the colours were identified, and instruments in different visual views and the instruments of differential display models were read. The colour rendering of the light source was also evaluated. Basic reliability may be chosen as 0.9995.

Significance of proliferating cell nuclear antigen expression in liver metastasis of colorectal cancer

PURPOSE

The study contained herein was aimed at finding some possible pathologic factors that have significance for the prediction of liver metastasis in colorectal cancer.

METHOD

Resected specimens of colorectal cancer from 23 patients with liver metastasis and 30 patients without liver metastasis were subjected to pathologic study, including microscopic characteristics and proliferating cell nuclear antigen immunohistochemistry assay.

RESULTS

Strongly positive expression of proliferating cell nuclear antigen was present in 65.21 percent (15/23) of the liver metastasis group, whereas it was found in only 20 percent (6/30) of the group without liver metastasis (P < 0.005). Deeper invasion to the muscularis propria or serosa and less infiltration of lymphocytes surrounding the tumor were more frequently found in the liver metastasis group than in the other group (P < 0.025).

CONCLUSION

Extent of proliferating cell nuclear antigen expression, depth of invasion, and reaction of lymphocyte infiltration of the primary tumor could have predictive significance of colorectal cancer in liver metastasis.