Serum concentrations of resistin and adiponectin and their relationship to insulin resistance in subjects with impaired glucose tolerance

OBJECTIVES

This study measured the serum concentrations of resistin and adiponectin in Chinese subjects with impaired glucose tolerance (IGT) and investigated their association with insulin resistance, metabolic parameters and circulating inflammatory markers.

METHODS

A total of 124 subjects participated in the study (44 with IGT and 80 with normal glucose tolerance [NGT]). Fasting serum concentrations of lipids, glucose, insulin and adipocytokines (resistin, adiponectin, leptin, tumour necrosis factor-α [TNF-α], interleukin-6 and C-reactive protein) were measured.

RESULTS

Serum resistin concentrations were similar in the IGT and NGT groups but were significantly higher in overweight/ obese IGT subjects than in those of normal weight. Serum adiponectin concentrations were significantly lower in the IGT group than in the NGT group. In the IGT group, resistin was positively correlated with age, body mass index and TNF-α, and adiponectin was correlated positively with high-density lipoprotein cholesterol and negatively with TNF-α and waist/hip ratio.

CONCLUSIONS

Circulating resistin is unlikely to be a major mediator of glucose tolerance in humans but it may have an inflammatory role in IGT. The data support the theory that circulating adiponectin has an anti-inflammatory and anti-insulin resistance function.

Excessive Wnt/β-catenin signaling disturbs tooth-root formation

BACKGROUND AND OBJECTIVE

Wingless-type MMTV integration site family (Wnt)/β-catenin signaling plays an essential role in cellular differentiation and matrix formation during skeletal development. However, little is known about its role in tooth-root formation. In a previous study, we found excessive formation of dentin and cementum in mice with constitutive β-catenin stabilization in the dental mesenchyme. In the present study we analyzed the molar roots of these mice to investigate the role of Wnt/β-catenin signaling in root formation in more detail.

MATERIAL AND METHODS

We generated OC-Cre:Catnb(+/lox(ex3)) mice by intercrossing Catnb(+/lox(ex3)) and OC-Cre mice, and we analyzed their mandibular molars using radiography, histomorphometry and immunohistochemistry.

RESULTS

OC-Cre:Catnb(+/lox(ex3)) mice showed impaired root formation. At the beginning of root formation in mutant molars, dental papilla cells did not show normal differentiation into odontoblasts; rather, they were prematurely differentiated and had a disorganized arrangement. Interestingly, SMAD family member 4 was upregulated in premature odontoblasts. In 4-wk-old mutant mice, molar roots were about half the length of those in their wild-type littermates. In contrast to excessively formed dentin in crown, root dentin was thin and hypomineralized in mutant mice. Biglycan and dentin sialophosphoprotein were downregulated in root dentin of mutant mice, whereas dentin matrix protein 1 and Dickkopf-related protein 1 were upregulated. Additionally, ectonucleotide pyrophosphatase/phosphodiesterase 1 was significantly downregulated in the cementoblasts of mutant molars. Finally, in the cementum of mutant mice, bone sialoprotein was downregulated but Dickkopf-related protein 2 was upregulated.

CONCLUSION

These results suggest that temporospatial regulation of Wnt/β-catenin signaling plays an important role in cell differentiation and matrix formation during root and cementum formation.

Polydatin Protects against Lipopolysaccharide-Induced Fulminant Hepatic Failure in D-Galactosamine-Sensitized Mice

Fulminant hepatic failure (FHF) is a devastating clinical syndrome with extremely poor prognosis and high mortality. Therefore, better treatment is urgently needed. Polydatin (PD), a traditional anti-inflammatory drug, has been described to protect against liver injury induced by certain hepatotoxins. The present study investigated the protective effect of PD against lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced FHF in mice and the underlying mechanism. Mice were pretreated with an increasing dose of PD (10, 30, and 100 mg/kg), following LPS/D-GalN challenge. The liver injury was assessed biochemically and histologically. We found that PD exerted a protective effect on LPS/D-GalN-induced FHF as evidenced by reducing sera alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, diminishing liver histopathological injury, and lowering mortality in a dose-dependent manner. In addition, pretreatment mice with PD dose-dependently suppressed tumor necrosis factor-α (TNF-α) production, myeloperoxidase (MPO) activity, intercellular adhesion molecule-1 (ICAM-1) and endothelial cell adhesion molecule-1 (ECAM-1) expression, caspase-3 activation, and transcription factor nuclear factor-kappa B(NF-kB) activity induced by LPS. These results suggested that PD could effectively protect from LPS/D-GalN-induced FHF and the protective effect afforded by PD probably contributed to reduce TNF-α production via inhibiting NF-kB activation.

Poster - Thur Eve - 70: Quantification of tumour dose enhancement at kilo-voltage energies due to the presence of gold nanoparticles during radiation therapy: EGSnrcMP Monte Carlo study

One of the greatest challenges in radiation therapy is the ability to deliver a lethal dose of radiation to a tumour while sparing the surrounding normal tissues. In theory, the dose delivered to a tumour during photon-based radiation therapy can be enhanced by loading high atomic number (Z) materials into the tumour, which results in greater photoelectric absorption and hence increased photoelectron fluence within the tumour than in surrounding tissues. The EGSnrcMP Monte Carlo code, together with DOSXYZnrc, a three-dimensional voxel dose calculation module has been used to study the macroscopic dose enhancement factor (MDEF) in a tumour infused with gold nanoparticles at the kilo-voltage energies. We observed that gold nanoparticles infused in a tumour irradiated with kilo-voltage energies has the potential to enhance the tumour dose by a factor ranging from 0.25 to about 5 depending on the mean energy of the beam and the concentration of gold nanoparticles in the tumour. The increase in dose can be attributed to the significant increase in the photoelectron fluence within the tumour loaded with gold particles during the irradiation. Future studies will involve the characterization of the MDEF at megavoltage energies.

Poster - Thur Eve - 77: Coordinate transformation from DICOM to DOSXYZnrc

DICOM format is the de facto standard for communications between therapeutic and diagnostic modalities. A plan generated by a treatment planning system (TPS) is often exported to DICOM format. BEAMnrc/DOSXYZnrc is a widely used Monte Carlo (MC) package for beam and dose simulations in radiotherapy. It has its own definition for beam orientation, which is not in compliance with the one defined in DICOM standard. Dose simulations using TPS generated plans require transformation of beam orientations to DOSXYZnrc coordinate system (c.s.) after extracting the necessary parameters from DICOM RP files. The transformation is nontrivial. There have been two studies for the coordinate transformations. The transformation equation sets derived have been helpful to BEAMnrc/DOSXYZnrc users. However, both the transformation equation sets are complex mathematically and not easy to program. In this study, we derive a new set of transformation equations, which are more compact, better understandable, and easier for computational implementation. The derivation of polar angle θ and azimuthal angle φ is similar to the existing studies by applying a series of rotations to a vector in DICOM patient c.s. The derivation of beam rotation Φ_col for DOSXYZnrc, however, is different. It is obtained by a direct combination of the actual collimator rotation with the projection of the couch rotation to the collimator rotating plane. Verification of the transformation has been performed using clinical plans created with Eclipse. The comparison between Eclipse and MC results show exact geometrical agreement for field placements, together with good agreement in dose distributions.

Sci-Thur AM: Planning - 12: Comparative study of SBRT lung dose calculation using Eclipse and Monte Carlo

Stereotactic Body Radiation Therapy (SBRT) is an option for early stage non-small cell lung cancer treatment. In SBRT treatment, high biological effective dose is delivered to the patient within a small number of fractions. High level of confidence in accuracy is required in the entire treatment procedure, from patient setup, tumour delineation, treatment simulation and planning, to the final dose delivery. SBRT lung treatment utilizes small fields that are incident on large tissue inhomogeneities within the patient. It is difficult for commercially available treatment planning systems (TPS) to model the lack of charged particle equilibrium and the dose near tissue-lung interfaces accurately. The Monte Carlo (MC) technique calculates the dose distribution from the first principles thereby providing a feasible tool for verifying the dose distribution computed from TPS. In this study, we compared the SBRT dose distribution between Eclipse 8.9 and BEAMnrc/DOSXYZnrc for both conformal and RapidArc plans. Calculation results for five clinical SBRT conformal lung plans were compared. Eclipse and MC results for each plan showed good agreement in dose received by organs at risk. MC simulation predicted uniformly hotter or similar PTV coverage for three cases with tumor either small or attached to the chest wall. When tumor is inside lung and at relatively medium to larger size for SBRT, MC predicted lower PTV coverage. The variation in dose coverage may depend on the tumour size and its position within the lung. Dose comparison for RapidArc plans shows similar dependence.

Subclinical atherosclerosis, airflow obstruction and emphysema: the MESA Lung Study

Airflow obstruction is an independent risk factor for cardiovascular events in the general population. The affected vascular bed and contribution of emphysema to cardiovascular risk are unclear. We examined whether an obstructive pattern of spirometry and quantitatively defined emphysema were associated with subclinical atherosclerosis in the carotid, peripheral and coronary circulations. The Multi-Ethnic Study of Atherosclerosis recruited participants aged 45-84 yrs without clinical cardiovascular disease. Spirometry, carotid intima-media thickness (IMT), ankle-brachial index (ABI) and coronary artery calcium (CAC) were measured using standard protocols. Percentage of emphysema-like lung was measured in the lung windows of cardiac computed tomography scans among 3,642 participants. Multiple linear regression was used to adjust for cardiac risk factors, including C-reactive protein. Decrements in forced expiratory volume in 1 s (FEV(1)) and FEV(1)/forced vital capacity ratio were associated with greater internal carotid IMT, particularly among smokers (p=0.03 and p<0.001, respectively) whereas percentage emphysema was associated with reduced ABI regardless of smoking history (p=0.004). CAC was associated with neither lung function (prevalence ratio for the presence of CAC in severe airflow obstruction 0.99, 95% CI 0.91-1.07) nor percentage emphysema. An obstructive pattern of spirometry and emphysema were associated distinctly and independently with subclinical atherosclerosis in the carotid arteries and peripheral circulation, respectively, and were not independently related to CAC.

Effect of ginsenoside Rg1 on proliferation and differentiation of human dental pulp cells in vitro

BACKGROUND

Human dental pulp cells (hDPCs) have the potency to proliferate and differentiate into odontoblasts and play an important role in dentine formation and reparation. The aim of the present study is to evaluate the effects of ginsenoside Rg1 on the proliferation and differentiation of hDPCs.

METHODS

hDPCs were incubated with different concentrations of ginsenoside Rg1 (0.1, 0.5, 2.5, 5, 10 and 20 μmol/L). The effects of ginsenoside Rg1 on the proliferative ability of hDPCs were evaluated by a fibroblast colony forming test, MTT assay and flow cytometry for cell cycle. The control group, osteogenic induction group, ginsenoside Rg1 (5 μmol/L) group and combination group were designed, and alkaline phosphatase (ALP) activity and FQ-PCR for gene expressions of dentine sialophosphoprotein (DSPP) and dentine matrix protein 1 (DMP1) were performed to evaluate the differentiation of hDPCs.

RESULTS

The proliferative ability of hDPCs in ginsenoside Rg1 was significantly enhanced (p < 0.05), especially in the ginsenoside Rg1 (5 μmol/L) group. ALP activity and gene expressions of DSPP and DMP1 were increased in the induction group, ginsenoside Rg1 group, and their combination group compared with the control group (p < 0.05).

CONCLUSIONS

The results indicate that ginsenoside Rg1 promotes the proliferation and differentiation of hDPCs.

Patterns of placental development evaluated by X chromosome inactivation profiling provide a basis to evaluate the origin of epigenetic variation

BACKGROUND

Inactivation of the maternally or paternally derived X chromosome (XCI) initially occurs in a random manner in early development; however as tissues form, a ‘patchiness’ will occur in terms of which X is inactivated if cells positioned near each other are clonally descended from a common precursor. Determining the relationship between skewed XCI in different tissues and in different samples from the same tissue provides a molecular assessment of the developmental history of a particular tissue that can then be used to understand how genetic and epigenetic variation arises in development.

METHODS

XCI skewing was evaluated in and compared between amnion, chorion, trophoblast and mesenchyme using multiple sampling sites from 14 term placentae. XCI was also evaluated in chorionic villus samples obtained at multiple sites and depths from four additional term placentae. The pattern of variation was then compared with methylation variation associated with the H19/IGF2 imprinting control region (ICR); promoter regions of KISS1, PTPN6, CASP8 and APC; and LINE-1 elements.

RESULTS

Mean placental level of skewing for amnion and chorion are correlated, consistent with a common developmental origin of at least a component of these membranes from inner cell mass derivatives subsequent to XCI, while trophoblast appears to be derived independently, consistent with its origin from the trophectoderm. Villus samples taken from different depths spanning the fetal to maternal side of the placenta were highly clonally related. Comparing patterns of clonal growth identified through XCI to the distribution of epigenetic variation in other genomic regions suggests that some variation arises early in development (e.g. LINE-1 methylation), whereas other variation arises predominantly after villus tree formation (e.g. methylation at H19/IGF2 ICR).

CONCLUSIONS

The patterns of XCI skewing are consistent with a model whereby each biopsied site of chorionic villi represents one or a few individual villus trees, each of which is clonally derived from only one or a few precursor cells. Sampling of placentae to evaluate changes associated with clinical pathology should be done with consideration of the tree-to-tree differences. A limitation of this study is the small number of placentas used and therefore placental-specific differences in variation could not be assessed.

Correlation between the band gap, elastic modulus, Raman shift and melting point of CdS, ZnS, and CdSe semiconductors and their size dependency

With structural miniaturization down to the nanoscale, the detectable quantities of solid materials no longer remain constant but become tunable. For the II-VI semiconductors example, the band gap expands, the elastic modulus increases, the melting point drops, and the Raman optical phonons experience red shift associated with creation of low frequency Raman acoustic modes that undergo blue shift with decreasing the dimensional scale. In order to understand the common origin of the size dependency of these seemingly irrelevant properties, we formulated these quantities for CdS, ZnS, and CdSe semiconductors from the perspectives of bond order-length-strength correlation and the local bond averaging approach. Consistency between the theory predictions and the measured size dependence of these quantities clarified that the undercoordination-induced local strain and quantum entrapment and the varied fraction of undercoordinated atoms of the entire solid correlate these quantities and dominate their size effect.

Novel magnetic chitosan/poly(vinyl alcohol) hydrogel beads: preparation, characterization and application for adsorption of dye from aqueous solution

Novel magnetic chitosan/poly(vinyl alcohol) hydrogel beads (m-CS/PVA HBs) were prepared by an instantaneous gelation method and characterized by X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA). Results of characterization indicated that m-CS/PVA HBs have been prepared successfully without damaging the crystal structure of Fe(3)O(4) and their saturation magnetization were about 21.96 emu g(-1). The adsorption capacity of Congo Red on the m-CS/PVA HBs was 470.1 mg g(-1). The adsorption was well described by pseudo-second-order kinetics and Langmuir equation. Positive value of enthalpy change (ΔH(∘)) (13.32 kJ mol(-1)) showed that the adsorption was endothermic and physical in nature. The values of Gibbs free energy change (ΔG(∘)) were found to be -3.321 kJ mol(-1) at 298 K for m-CS/PVA HBs, indicating the spontaneity of Congo Red adsorption. Therefore, the m-CS/PVA HBs could be employed as a low-cost alternative to other adsorbents in the removal of dyes from aqueous solution.

Predictors of survival in patients with recurrent ovarian cancer undergoing secondary cytoreductive surgery based on the pooled analysis of an international collaborative cohort

BACKGROUND

This study aims to identify prognostic factors and to develop a risk model predicting survival in patients undergoing secondary cytoreductive surgery (SCR) for recurrent epithelial ovarian cancer.

METHODS

Individual data of 1100 patients with recurrent ovarian cancer of a progression-free interval at least 6 months who underwent SCR were pooled analysed. A simplified scoring system for each independent prognostic factor was developed according to its coefficient. Internal validation was performed to assess the discrimination of the model.

RESULTS

Complete SCR was strongly associated with the improvement of survival, with a median survival of 57.7 months, when compared with 27.0 months in those with residual disease of 0.1-1 cm and 15.6 months in those with residual disease of >1 cm, respectively (P<0.0001). Progression-free interval (≤23.1 months vs >23.1 months, hazard ratio (HR): 1.72; score: 2), ascites at recurrence (present vs absent, HR: 1.27; score: 1), extent of recurrence (multiple vs localised disease, HR: 1.38; score: 1) as well as residual disease after SCR (R1 vs R0, HR: 1.90, score: 2; R2 vs R0, HR: 3.0, score: 4) entered into the risk model.

CONCLUSION

This prognostic model may provide evidence to predict survival benefit from secondary cytoreduction in patients with recurrent ovarian cancer.

New red flower germplasm lines of cotton selected from hybrid ofGossypium hirsutum XG. bickii

By means of dropping GA(3)(50 ppm) and NAA (40 ppm) on the hybrid boll-embryo culturein vitro, one F(1) plant ofG. hirsutum x G. bickii was obtained; when F(1) branches were grafted on upland cotton and then back-crossed with upland cotton under short-day and cooler-night condition, some BC(1) seeds could be harvested. The characteristic segregation was very violent in early generation. Through 3 times of back-crossing and selecting, ten stable hybrid lines with the character of both male parent (viz. red petal-purple spot and strong fibre) and female parent (plant type, earliness, white fibre, lint length, etc.) were established. These lines were assigned as HB red flower lines (HBRL). Transference of character ofG. bickii to upland cotton was proved to be successful for the first time. These new germplasms may play an important role in both the genetic research and new cotton variety breeding.

Evaluating DNA methylation and gene expression variability in the human term placenta

Obtaining representative samples from a term placenta for gene-expression studies is confounded by both within placental heterogeneity and sampling effects such as sample location and processing time. Epigenetic processes involved in the regulation of gene expression, such as DNA methylation, may show similar variability, but are less well studied. Therefore, we investigated the nature of within and between- placenta variation in gene expression and DNA methylation of genes that were chosen for being differentially expressed or methylated by cell type within the placenta.

METHODS

In total, two or more samples from each of 38 normal term placentae were utilized. The expression levels of CDH1, CDH11, ID2, PLAC1 and KISS1 were evaluated by real-time PCR. DNA methylation levels of LINE1 elements and CpGs within the promoter regions of KISS1, PTPN6, CASP8, and APC were similarly quantified by pyrosequencing.

RESULTS

Despite considerable sample-to-sample variability within each placenta, the within-placenta correlation for both gene expression and methylation was significant for each studied gene. Most of this variability was not due to sample location. However, between placental differences in gene expression were inflated by the dramatic effect of processing time (0-24 h) on mRNA levels, particularly for PLAC1 and KISS1 (both expressed in the apical syncytiotrophoblast). In contrast, DNA methylation levels remained relatively constant over this same time period.

CONCLUSION

Due to extensive site-to-site variability, multiple sampled sites are needed to accurately represent a placenta for molecular studies. Furthermore, mRNA quantitation of some genes may be hampered by its rapid degradation post-delivery (and possibly perinatally) and thus processing time should be considered in such analyses. Within-placenta correlations in expression and methylation from unrelated genes raise the possibility that methylation and expression variation may potentially reflect cell composition differences between samples rather than true differences occurring at the cellular level.

Prioritisation of associations between protein domains and complex diseases using domain-domain interaction networks

It is of vital importance to find genetic variants that underlie human complex diseases and locate genes that are responsible for these diseases. Since proteins are typically composed of several structural domains, it is reasonable to assume that harmful genetic variants may alter structures of protein domains, affect functions of proteins and eventually cause disorders. With this understanding, the authors explore the possibility of recovering associations between protein domains and complex diseases. The authors define associations between protein domains and disease families on the basis of associations between non-synonymous single nucleotide polymorphisms (nsSNPs) and complex diseases, similarities between diseases, and relations between proteins and domains. Based on a domain-domain interaction network, the authors propose a 'guilt-by-proximity' principle to rank candidate domains according to their average distance to a set of seed domains in the domain-domain interaction network. The authors validate the method through large-scale cross-validation experiments on simulated linkage intervals, random controls and the whole genome. Results show that areas under receiver operating characteristic curves (AUC scores) can be as high as 77.90%, and the mean rank ratios can be as low as 21.82%. The authors further offer a freely accessible web interface for a genome-wide landscape of associations between domains and disease families.

Preparation, characterization, adsorption kinetics and thermodynamics of novel magnetic chitosan enwrapping nanosized gamma-Fe2O3 and multi-walled carbon nanotubes with enhanced adsorption properties for methyl orange

A novel magnetic composite bioadsorbent composed of chitosan wrapping magnetic nanosized gamma-Fe(2)O(3) and multi-walled carbon nanotubes (m-CS/gamma-Fe(2)O(3)/MWCNTs) was prepared under relative mild conditions and was characterized. Adsorption of methyl orange (MO) onto m-CS/gamma-Fe(2)O(3)/MWCNTs was investigated with respect to pH, initial MO concentration, coexisting anions and temperature. Results of characterizations indicated that magnetic nanosized gamma-Fe(2)O(3) and MWCNTs have been wrapped by crosslinked chitosan. Introduction of MWCNTs could obviously increase the adsorption capacity (q(e)) of MO onto bioadsorbent by 2.2 times. Kinetics data and adsorption isotherm were better fitted by pseudo-second-order kinetic model and by Langmuir isotherm, respectively. Values of activation parameters such as free energy ( big up tri, openG degrees ), enthalpy ( big up tri, openH degrees ) and entropy (DeltaS degrees ) were determined as 3.15-3.78 kJ mol(-1), -9.94 kJ mol(-1) and -20.65 J mol(-1)k(-1), respectively, indicating that the adsorption was feasible, spontaneous and exothermic process in nature. After adsorption, m-CS/gamma-Fe(2)O(3)/MWCNTs could be effectively and fleetly separated by applying a magnetic field.

Genetic variation in glutathione metabolism and DNA repair genes predicts survival of small-cell lung cancer patients

BACKGROUND

Small-cell lung cancer (SCLC) carries the worst prognosis among lung cancer diagnoses. Combined radiation and chemotherapy is the standard of care; however, treatment outcomes vary. Variability in the rate at which chemotherapy agents are metabolized and in the capacity of repairing DNA damage has been hypothesized to be partly responsible for the treatment response variation. Genes in the glutathione metabolism and DNA repair pathways were tested through tag single-nucleotide polymorphisms (SNPs) to assess their association with survival in SCLC.

PATIENTS AND METHODS

Blood DNA from 248 patients with primary SCLC was genotyped for 419 tag SNPs from 49 genes in the glutathione and DNA repair pathways. Association analyses with patient survival were carried out at single-SNP, whole-gene, and haplotype levels after adjusting for age, gender, tumor stage, treatment modalities, and smoking history.

RESULTS

Among the 375 SNPs successfully genotyped, 21 SNPs, located on 11 genes, showed significant association with survival. Whole-gene analyses confirmed 3 of the 11 genes: GSS, ABCC2, and XRCC1. Haplotype analyses of these three genes identified haplotype combinations and genomic locations underlying the observed SNP associations.

CONCLUSION

Genetic variations in genes involved in the glutathione and DNA repair pathways are associated with SCLC survival.

Induction of tumoricidal activity in mouse peritoneal macrophages by ginseng polysaccharide

This study examined the effects of ginseng polysaccharide (GPS) on mouse peritoneal macrophage (PM)-mediated cytotoxicity towards K562, HL-60, or KG1alpha cells. GPS had no direct effect on killing of tumor cells. However, when mouse PMs were treated with GPS, cytotoxic activity against K562, HL-60, or KG1alpha cells was significantly induced. In addition, phagocytic activity was enhanced in GPS-treated mouse PMs compared to the control. The expressions of CD(68), ACP and alpha-ANE in mouse PMs were increased by the treatment with GPS. Moreover, the levels of cytokines, including tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), IL-6 were increased and the production of nitric oxide (NO) was enhanced. Taken together, these results suggest that GPS possess a potent antitumor activity by stimulating macrophage and a potentiality as an immunomodulator against diseases such as cancer.

Total saponins of Panax ginseng (TSPG) promote erythroid differentiation of human CD34+ cells via EpoR-mediated JAK2/STAT5 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Total saponins of Panax ginseng (TSPG), main constituents extracted from Panax ginseng, a highly valued traditional Chinese medicine, have been shown to be an effective agent on hematopoiesis.

OBJECTIVE

To investigate the effect and mechanism underlying in which TSPG promote human CD34(+) hematopoietic stem and progenitor cells to differentiate into erythroid-lineage cells.

MATERIALS AND METHODS

The effect of TSPG on erythroid differentiation of purified CD34(+) cells derived from umbilical cord blood (UCB) was determined by methylcellulose assay system and colorimetry for hemoglobin content. The changes of EpoR expression in umbilical cord blood mononuclear cells (UCB-MNCs) and purified CD34(+) cells were detected with Western blotting and flow cytometry, respectively, and observed under laser scanning confocal microscope (LSCM). RT-PCR was performed to examine EpoR mRNA expression in CD34(+) cells. The effects of TSPG-pretreatment on Epo-induced JAK(2) and STAT(5) tyrosine phosphorylation were analyzed by immunoprecipitation.

RESULTS

The addition of TSPG (20-70 mg/L) increased the colony formation rate of BFU-E. TSPG (50 mg/L) alone used significantly increased the hemoglobin content, the addition of AG490 evidently reduced TSPG-induced elevation of hemoglobin content. TSPG increased the expression of EpoR on the surface membrane of CD34(+) cells but did not change the expression of EpoR in total UCB-MNCs. TSPG also increased the expression of EpoR mRNA in CD34(+) cells. TSPG markedly enhanced Epo-induced tyrosine phosphorylation of JAK(2) and STAT(5) in UCB-MNCs.

CONCLUSION

These findings suggest that TSPG may enhance the erythroid differentiation of hematopoietic stem and progenitor cells via Epo/EpoR-mediated JAK(2)/STAT(5) signaling pathway.

The role of secondary cytoreductive surgery for recurrent mucinous epithelial ovarian cancer (mEOC)

BACKGROUND

Mucinous epithelial ovarian cancer (mEOC) may exhibit a distinct biological behavior in epithelial ovarian cancer (EOC). The role of secondary cytoreductive surgery was evaluated in patients with recurrent mEOC, and the prognosis was assessed.

METHODS

Twenty-one patients with stages IIc to IV mEOC who experienced disease recurrence and received secondary cytoreductive surgery at Fudan University Cancer Hospital between Jan. 1997 and Dec. 2005 were retrospectively reviewed. Survival curves were generated using the Kaplan-Meier method and the significant comparison of survival rate was estimated by the log-rank test.

RESULTS

The median progression-free interval (PFI) was 14 months (range, 5-46 months) after the first cytoreduction. Seven patients (33%) who received secondary cytoreductive surgery were optimally cytoreduced with residual disease less than or equal 1cm, and the other 14 patients (67%) underwent suboptimal surgical cytoreduction. The overall median survival time was 27 months (range, 8-64 months). The median survival time after recurrence was 10 months (range, 3-32 months). There was no significant statistical difference in median survival between patients with optimal and suboptimal secondary surgical cytoreduction, with an estimated survival of 10 months and 9.8 months, respectively (P>0.05).

CONCLUSION

Optimal primary cytoreductive surgery for advanced mEOC was very important. Once it recurs, the prognosis is very poor. Patients with recurrent mEOC should be carefully assessed before performing secondary cytoreductive surgery, as this may have limited impact on the overall survival rates.

Downregulation of Wnt2 and beta-catenin by siRNA suppresses malignant glioma cell growth

Increasing evidence suggests that aberrant activation of Wnt signaling is involved in tumor development and progression. Our earlier study on gene expression profile in human gliomas by microarray found that some members of Wnt family were overexpressed. To further investigate the involvement of Wnt signaling in gliomas, the expression of core components of Wnt signaling cascade in 45 astrocytic glioma specimens with different tumor grades was examined by reverse transcription-PCR and immunohistochemistry. Wnt2, Wnt5a, frizzled2 and beta-catenin were overexpressed in gliomas. Knockdown of Wnt2 and its key mediator beta-catenin in the canonical Wnt pathway by siRNA in human U251 glioma cells inhibited cell proliferation and invasive ability, and induced apoptotic cell death. Furthermore, treating the nude mice carrying established subcutaneous U251 gliomas with siRNA targeting Wnt2 and beta-catenin intratumorally also delayed the tumor growth. In both in vitro and in vivo studies, downregulation of Wnt2 and beta-catenin was associated with the decrease of PI3K/p-AKT expression, indicating the interplay between Wnt/beta-catenin and PI3K/AKT signaling cascades. In conclusion, the canonical Wnt pathway is of critical importance in the gliomagenesis and intervention of this pathway may provide a new therapeutic approach for malignant gliomas.

Tailored regimen of interferon alpha for HBeAg-positive chronic hepatitis B: a prospective controlled study

The response to interferon-alpha treatment of patients with chronic hepatitis B under the current protocol is not satisfactory. The aim of this study was to try an alternative approach to improve treatment outcome. Of 374 HBeAg-positive patients, 127 of them received 5 million units of interferon-alpha thrice weekly for 6 months and constituted the control group, while 247 in the study group received the same dosage but the duration of treatment was tailored. The study protocol provided for continuation of treatment if HBV DNA levels were continuously decreasing. The treatment ended when viral, antigenic and biochemical endpoints were reached or when HBV DNA levels were no longer decreasing. The median length of tailored treatment was 10 (range 6-24) months. The end-of-treatment response rates were 39.3% and 23.6% (P = 0.002), and after 12-month, follow-up, the sustained response rates were 40.5% and 28.3% (P = 0.013) in the study and control groups, respectively. Excluding the patients who dropped out, 228 and 115 completed a median of 40- and 44-month-long follow-up; the long-term response was thus 45.3% and 33.1% (P = 0.014) in the respective groups. Interferon-alpha treatment tailored in length demonstrated significantly increased efficacy in patients with chronic hepatitis B.

Correlation of population parameters leading to power differences in association studies with population stratification

The power of statistical tests to measure effect sizes in the presence of population stratification is an important issue for the design and analysis of population-based association studies. Comparisons of statistical tests have shown that the power of different statistical approaches varies in different genetic scenarios. However, the impact of stratified population parameters on statistical power is not yet understood in a general statistical framework, particularly the impact of correlated population parameters. To investigate such impact in detail, we implemented a genetic model for population-based association studies with stratified samples and evaluated the impact on power with different genetic scenarios. The investigation shows that correlation between disease prevalence and risk allele frequency among subpopulations impacts statistical power. In a model with five subpopulations and moderate population divergence (Fst= 0.01), the correlation accounts for more than 85% of power difference. Our results also show that the estimation of genetic effect for candidate loci is biased by population divergence. Beneficial alleles could be wrongly characterized as risk alleles when prevalence differences and divergences of risk loci are large among subpopulations.