Identification of P4HA1 as a prognostic biomarker for high-grade gliomas

BACKGROUND

Prolyl 4-Hydroxylase Subunit Alpha 1 (P4HA1) is the active catalytic component of prolyl 4-hydroxylase and plays a crucial role in modulating extracellular matrix hemostasis. P4HA1 has been reported to promote tumor progression by enhancing invasion and angiogenesis. Overexpression of P4HA1 is associated with decreased survival for patients with breast and prostate cancer. However, the prognostic significance of P4HA1 for glioma patients remains undefined.

METHODS

The expression of P4HA1 in 290 gliomas (WHO grade II-IV) and 10 normal brain tissues was examined with TMA-based immunohistochemistry assay. The correlation between P4HA1 expression and clinicopathological parameters as well as the prognosis of glioma patients was investigated.

RESULTS

Cytoplasmic expression of P4HA1 is high in 37.93% of all glioma cases, with 44.98% in high-grade gliomas and 19.75% in low-grade gliomas respectively. Increased P4HA1 level was correlated with advanced histological grade (p<0.01) and old age (p=0.01). Upregulation of P4HA1, as well as histological grade, was an independent risk factor for unfavorable prognosis. Subgroup analysis demonstrated that high P4HA1 expression was significantly associated with poor prognosis for high-grade gliomas (p<0.01) but not for low-grade gliomas.

CONCLUSIONS

P4HA1 was upregulated in gliomas. High expression of P4HA1 was correlated with the malignancy of gliomas and could serve as a prognostic indicator for patients with high-grade gliomas.

[Evaluation of health effect among occupational population exposed to nano-titanium dioxide: a cross-sectional study]

Objective: To characterize the health effects of nano-titanium dioxide exposure in an occupational cohort. Methods: Eighty-five male employees of a nano-titanium dioxide manufacturing enterprise in Shandong Province were evaluated in September 2014. Forty-four were exposed to nano-titanium dioxide (exposure group), and 41 were not exposed to nano-titanium dioxide (control group). We collected employees' basic information, smoking and drinking history, previous medical history, family history, and occupational history. Differences in blood pressure, hematological parameters, and blood biochemistry between the two groups were analyzed and compared. Multiple linear regression analysis was used to investigate the effect of nano-titanium dioxide exposure on blood pressure, hematological parameters, and blood biochemistry indices after controlling for age, smoking, drinking, and body mass index (BMI). Twenty-five employees from the exposure group and 25 employees from the control group were selected at random for measurement of genetic damage by cytokinesis-block micronucleus assay. Poisson regression analysis was used to investigate the effect of nano-titanium dioxide exposure on micronucleus frequency or micronucleus cell frequency after controlling for age, smoking, drinking, and BMI. Results: The median (P₂₅-P₇₅) surface area concentration of particles deposited in the tracheobronchial region, the surface area concentration of particles deposited in the alveolar region, and particle number concentration in the exposure group were 35.35(24.31-57.42) μ m²/cm³, 173.09(116.27-270.72) μ m²/cm³, and 40 244.00 (17 803.50-78 679.00) /cm³, respectively. These values were significantly higher than those in the control group 33.90 (27.44-43.29) μm²/cm³, 150.50(125.82-192.87)μm²/cm³, and 18 721.00 (12 721.00-51 898.50)/cm³, respectively. Z values were 15.47, 15.96, and 14.54, respectively (P<0.001 for all three values). Multiple linear regression analysis showed that exposure to nano-titanium dioxide contributed most to the alteration of mean corpuscular hemoglobin concentration, creatinine, and LDL-C, with standardized regression coefficients of 0.23, -0.51, and 0.30, respectively (P<0.05 for all three values), after adjusting for age, smoking, drinking, and BMI. There were no significant differences in micronucleus frequency and micronucleus cell frequency between the exposure group (3.00‰ (1.50‰-5.00‰) and 3.00‰ (2.00‰-4.00‰), respectively) and control group (2.00‰ (1.00‰-4.50‰) and 2.00‰ (1.00‰-4.00‰), respectively); P>0.05 for all comparisons. Poisson regression analysis showed that after adjusting for age, smoking, drinking, and BMI, there was still no statistically significant correlation between nano-titanium dioxide exposure and micronucleus frequency (OR=1.11, 95% CI: 0.81-1.54) or micronucleus cell frequency (OR=1.07, 95% CI: 0.75-1.51); P>0.05 for all comparisons. Conclusion: Nano-titanium dioxide particles exerted some health effects on the occupationally-exposed cohort, whose hematological parameters and blood biochemistry were influenced to some degree. However, a potential link between occupational exposure to nano-titanium dioxide and blood pressure or induction of genetic damage or was not found.

A quasi-3D wire approach to model pulmonary airflow in human airways

The models used for modeling the airflow in the human airways are either 0-dimensional compartmental or full 3-dimensional (3D) computational fluid dynamics (CFD) models. In the former, airways are treated as compartments, and the computations are performed with several assumptions, thereby generating a low-fidelity solution. The CFD method displays extremely high fidelity since the solution is obtained by solving the conservation equations in a physiologically consistent geometry. However, CFD models (1) require millions of degrees of freedom to accurately describe the geometry and to reduce the discretization errors, (2) have convergence problems, and (3) require several days to simulate a few breathing cycles. In this paper, we present a novel, fast-running, and robust quasi-3D wire model for modeling the airflow in the human lung airway. The wire mesh is obtained by contracting the high-fidelity lung airway surface mesh to a system of connected wires, with well-defined radii. The conservation equations are then solved in each wire. These wire meshes have around O(1000) degrees of freedom and hence are 3000 to 25 000 times faster than their CFD counterparts. The 3D spatial nature is also preserved since these wires are contracted out of the actual lung STL surface. The pressure readings between the 2 approaches showed minor difference (maximum error = 15%). In general, this formulation is fast and robust, allows geometric changes, and delivers high-fidelity solutions. Hence, this approach has great potential for more complicated problems including modeling of constricted/diseased lung sections and for calibrating the lung flow resistances through parameter inversion.

[Application of long term video electroencephalogram and resting-state functional magnetic resonance imaging in detection of cognition in patients with benign epilepsy of childhood with centrotemporal spikes]

Objective: To study the relationship between the changes of brain network and cognition in patients with benign epilepsy of childhood with centrotemporal spikes (BECTS) by using long term video electroencephalogram (VEEG) and resting-state functional magnetic resonance imaging (RS-fMRI) technology. Methods: Eleven patients with right-handed were recruited (from April 2015 to September 2016) from epilepsy specialist outpatients and functional department of neurosurgery of Tianjin Medical University General Hospital. They all underwent the long term VEEG monitoring (one sleep cycle was included at least). According to the spike-wave index (SWI) during slow ware sleep, they were divided into two groups: SWI<50% (5 cases) and SWI≥50% (6 cases). All the patients were assessed with cognitional test including language, execution, memory and attention. They also underwent the head MRI, RS-fMRI examinations. Then the results were comparatively analysed. Results: (1)There were no statisticaly significance in sex, age, age of onset, disease course, total number of seizures, years of education (P>0.05). The Full Intelligence Quotient (FIQ) (87±18), Verbal Intelligence Quotient (VIQ) (88±15) and Performance Intelligence Quotient (PIQ) (89±20) of SWI≥50% group were lower than SWI<50% group(118±8, 114±11, 119±5) and the differences were statistically significant(P<0.05). (2)There was a negative correlation between the FIQ (P=0.002), VIQ (P=0.006), PIQ (P=0.001) and SWI. The FIQ, VIQ and PIQ had no correlation with the sex, age, age of onset, disease course, total number of seizures, years of education (P>0.05). (3)Compared with SWI<50% group, SWI≥50% group showed increased regional homogeneity (ReHo) in the bilateral precentral gyrus, premotor area and the subcortical structure, the right temporal lobe and the bilateral insular lobe(P<0.05); while they showed decreased ReHo in the posterior cingulate gyrus, right posterior inferior temporal lobe and right occipital lobe(P<0.05). Conclusion: The change of the brain network which is caused by the paradoxical and constant discharge during slow ware sleep in patients with BECTS may affect the development of cognition.

[Pre- and post-orthotopic heart transplantation electrocardiogram characteristics of 998 patients]

Objective: To analyze pre- and post-operation electrocardiograms (ECGs) features of patients underwent orthotopic heart transplantation (OHT), and provide evidences for identifying and analyzing post OHT ECGs. Methods: Nine hundreds and ninty-eight pre- and post- OHT standard 12-leads ECGs from 110 consecutive patients, who underwent OHT in our hospital from May 2008 to May 2014, were analyzed. Results: The mean heart rate(HR)was (86.9±16.4) beats per minute before OHT, and (100.0±0.4) beats per minute after OHT. P wave's amplitude, duration, amplitude multiplied by duration of donor heart in lead Ⅱ were (0.124±0.069)mV, (111.1±17.2)ms, (14.34±9.51)mV·ms before OHT; (0.054±0.037)mV, (86.9±27.0)ms, (5.02±4.03)mV·ms at 1 month after OHT; (0.073±0.049)mV, (93.9±17.5) ms, (7.00±4.81)mV·ms at 6 years after OHT. ECGs rotation occurred in 83.64%(92/110) patients after OHT, and prevalence of clockwise rotation was 76.36%(84/110). Sinus tachycardia was evidenced in 99.09%(109/110) patients after OHT, and incomplete right bundle branch block was present in 60.91%(67/110) patients after OHT. Pseudo complete atrioventricular block mostly occurred at 2 days after OHT. Prevalence of double sinus rhythm was 27.95%(263/941) post OHT, 40% of them occurred between the 1st and the 2nd month post OHT; the atrial rate of recipient hearts was (104.0±10.2) beats per minucte between the 3rd and the 6th month post OHT, and was (95.3±4.2) beats per minucte between the 4th year and the 5th year. P wave's amplitude, duration, amplitude multiplied by duration of recipient heart in lead Ⅱ were (0.066±0.055) mV, (52.8±34.7) ms, (4.67±4.95) mV·ms at 1 month after OHT, (0.043±0.040)mV, (44.4±40.5) ms , (3.11±3.61) mV·ms between the 1st year and 2nd year after OHT. The absolute value of P-wave(originating from the donor heart) terminal force in chest leads increased in 48.99%(461/941) patients post OHT, the P-wave terminal force of V(1) , V(2) and V(3) were -0.044(-0.066, -0.028), -0.060(-0.087, -0.038), -0.035(-0.056, 0) mm·s. Notched P wave in chest leads was presented in 10.31%(97/941) patients post OHT. PR segment depression in chest leads occurred in 60.24%(100/166) patients between the 3rd month and the 6th month, the incidence of PR segment depression in V(1) , V(2) and V(3) was 21.04%(198/941), 37.41%(352/941) and 28.69%(270/941), respectively. Conclusions: OHT is related to significantly changed ECGs. The mean HR increased significantly after OHT, then decreased gradually after half a year to one year, but it was still higher than preoperative mean HR after five or six years; the P waves of donor heart were usually inconspicuous or small in first month after OHT, and they became bigger after 2 months, and their duration and amplitude then became relatively steady afterwards. ECGs rotation, especially the clockwise rotation, was common post OHT. A variety of arrhythmias originating from the donor heart including sinus tachycardia and incomplete right bundle branch block could be found. Pseudo complete atrioventricular block could also be found in the early phase after OHT. With the extension of time, the incidence of double sinus rhythm reduced gradually. The atrial rate and P wave of recipient heart presented with a tendency to become lower. The absolute value of P-waves(originating from the donor heart) terminal force in chest leads (mainly V(1), V(2) and V(3)) increased, notched P waves in chest leads (mainly V(1), V(2)) and PR segments depression in chest leads (mainly V(2), V(3) and V(4)) also belong to typical post OHT ECGs features.

Three-dimensional cavity nanoantennas with resonant-enhanced surface plasmons as dynamic color-tuning reflectors

As plasmonic antennas for surface-plasmon-assisted control of optical fields at specific frequencies, metallic nanostructures have recently emerged as crucial optical components for fascinating plasmonic color engineering. Particularly, plasmonic resonant nanocavities can concentrate lightwave energy to strongly enhance light-matter interactions, making them ideal candidates as optical elements for fine-tuning color displays. Inspired by the color mixing effect found on butterfly wings, a new type of plasmonic, multiresonant, narrow-band (the minimum is about 45 nm), high-reflectance (the maximum is about 95%), and dynamic color-tuning reflector is developed. This is achieved from periodic patterns of plasmonic resonant nanocavities in free-standing capped-pillar nanostructure arrays. Such cavity-coupling structures exhibit multiple narrow-band selective and continuously tunable reflections via plasmon standing-wave resonances. Consequently, they can produce a variety of dark-field vibrant reflective colors with good quality, strong color signal and fine tonal variation at the optical diffraction limit. This proposed multicolor scheme provides an elegant strategy for realizing personalized and customized applications in ultracompact photonic data storage and steganography, colorimetric sensing, 3D holograms and other plasmon-assisted photonic devices.

Demonstration of patterned polymer-stabilized cholesteric liquid crystal textures for anti-counterfeiting two-dimensional barcodes

We evaluated the feasibility of embedding periodically arranged squares with planar and vertical texture into a background with a developable-modulation (DM) type cholesteric liquid crystal (CLC) fingerprint texture by a two-step ultraviolet-induced polymerization method. Checker-patterned optical diffractive elements, which can be seen as a variation of a two-dimensional (2D) barcode, were first realized and the dependence of diffraction behaviors on incident light polarization and applied voltage were investigated. Taking advantage of the natural randomness and uncontrollable variations of a DM-type fingerprint textures, a polymer-stabilized CLC (PSCLC) graphic symbol with a 2D barcode pattern was then implemented with enhanced anti-counterfeiting features that are difficult to falsify or duplicate. The results indicate that the multiplexing of nonuniform DM-type fingerprint gratings, cross-polarized light readout, and unique polarization diffraction characteristics can improve the level of security.

Measurement and simulation of the response function of time of flight enhanced diagnostics neutron spectrometer for beam ion studies at EAST tokamak

The 2.5 MeV TOFED (Time-Of-Flight Enhanced Diagnostics) neutron spectrometer with a double-ring structure has been installed at Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas. This work describes the response function of the TOFED spectrometer, which is evaluated for the fully assembled instrument in its final layout. Results from Monte Carlo simulations and dedicated experiments with pulsed light sources are presented and used to determine properties of light transport from the scintillator. A GEANT4 model of the TOFED spectrometer was developed to calculate the instrument response matrix. The simulated TOFED response function was successfully benchmarked against measurements of the time-of-flight spectra for quasi-monoenergetic neutrons in the energy range of 1-4 MeV. The results are discussed in relation to the capability of TOFED to perform beam ion studies on EAST.

Neutron emission spectroscopy of DT plasmas at enhanced energy resolution with diamond detectors

This work presents measurements done at the Peking University Van de Graaff neutron source of the response of single crystal synthetic diamond (SD) detectors to quasi-monoenergetic neutrons of 14-20 MeV. The results show an energy resolution of 1% for incoming 20 MeV neutrons, which, together with 1% detection efficiency, opens up to new prospects for fast ion physics studies in high performance nuclear fusion devices such as SD neutron spectrometry of deuterium-tritium plasmas heated by neutral beam injection.

Response function of single crystal synthetic diamond detectors to 1-4 MeV neutrons for spectroscopy of D plasmas

A Single-crystal Diamond (SD) detector prototype was installed at Joint European Torus (JET) in 2013 and the achieved results have shown its spectroscopic capability of measuring 2.5 MeV neutrons from deuterium plasmas. This paper presents measurements of the SD response function to monoenergetic neutrons, which is a key point for the development of a neutron spectrometer based on SDs and compares them with Monte Carlo simulations. The analysis procedure allows for a good reconstruction of the experimental results. The good pulse height energy resolution (equivalent FWHM of 80 keV at 2.5 MeV), gain stability, insensitivity to magnetic field, and compact size make SDs attractive as compact neutron spectrometers of high flux deuterium plasmas, such as for instance those needed for the ITER neutron camera.

[Resting-state functional magnetic resonance study of the brain's network of the temporal lobe epilepsy patients with depression]

OBJECTIVE

To study brain networks of temporal lobe epilepsy (TLE) to investigate whether TLE brain dysfunction have an impact on depression, using resting state functional magnetic resonance (RS-fMRI) detection technology.

METHODS

A total of 18 patients with TLE were included in this study. According to Beck Depression Inventory (BDI) and Hamilton's Depression Scale (HAMD)-17 score, we divided them into two groups: depression group 9 cases, non-depression group 9 cases. All patients underwent 3.0T MRI , RS-fMRI and magnetic resonance spectroscopy (MRS) examinations and then the results were analyzed.

RESULTS

Disease course of depression group was longer than non-depression group and the difference was statistically significant (P<0.05). RS-fMRI examination showed that depression group had more active brain areas and more extral temporal active areas than non-depression group (P<0.05). By compared with the non-depression group, we found more strong active brain areas including thalamus, and the default-mode network which involved in prefrontal cortex, precuneus, ventral anterior cingulate and hippocampus. We found the NAA and NAA/Cho+ Cr of the hippocampus which were ipsilateral to the advantage discharge side were decreased in 5/9 cases with depression in MRS and 3/5 cases had hippocampal atrophy, while the non-depression group had no obvious abnormalities.

CONCLUSION

The brain default-mode network activity in TLE patients with depression is increased and there is more extral temporal activation than the non-depression group; furthermore abnormal hippocampus structure is more common in depression group, which suggests that epileptic brain dysfunction may affect the development of depression.

[Effects of cystectomy for ovary benign cyst on ovarian reserve and pregnancy outcome of in vitro fertilization-embryo transfer cycle]

OBJECTIVE

To investigate the impact of previous cystectomy for ovary benign cyst on ovarian reserve and pregnancy outcome in in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) cycles.

METHODS

Totally 622 infertility patients were retrospectively investigated who underwent first IVF/ICSI-ET cycle in Reproductive Hospital Affiliated to Shandong University from January 2013 to June 2014. There were 153 cases who had been removed ovarian cyst by cystectomy surgeries recruited as study group, in which 44 cases of ovarian endometriosis cyst, 35 cases of benign ovarian teratomas, 67 cases of simple ovarian cyst and 7 cases of ovarian mucinous cystadenoma. In contrast, 469 infertility patients with tubal-factor infertility or male factor were included as control group. The age-matched women in the control group had no ovarian surgery previously. The indicators of ovarian reserve and pregnancy outcome were analyzed between two groups. The influence of different types of ovarian cysts on ovarian reserve and pregnancy outcome in IVF/ICSI-ET cycles were also studied, ovarian endometriosis cyst was studied as Group A, and Group B consisted of benign ovarian teratomas, simple ovarian cyst and mucinous cystadenoma.

RESULTS

(1) The significantly lower serum antimullerian hormone (AMH) level (median: 1.92 versus 2.90 mg/L), antral follicle count (AFC; median: 12.0 versus 13.0), retrieved oocytes (12±5 versus 13±6) and the number of embryo cryopreserved (median: 1.0 versus 3.0) were found in study group compared with control group (all P<0.05). There was no statistical difference between two group for the following parameters, such as basal FSH level, the total dosage of gonadotropin duration and the total dosage of gonadotropin (all P>0.05). A better clinical pregnancy rate was achieved in control group (61.6%, 241/391) than that in study group (61.4%, 81/132), but no significant difference was existed (P=0.96). (2) Compared to Group B, Group A had fewer AFC, lower serum AMH level, retrieved oocytes and the number of embryo cryopreserved (11±4 versus 13±5; 1.65 versus 2.15 mg/L; 9±4 versus 13±5; 0 versus 2.0; all P< 0.01). There was a lower clinical pregnancy rate in Group A than that in Group B [50.0% (19/38) versus 66.0% (62/94)], accompanying with higher abortion rate [3/19 versus 9.7% (6/62)], but no differences were observed (all P>0.05).

CONCLUSIONS

Ovarian reserve declines after the cystectomy for ovarian benign cysts and the cystectomy has a negative impact on IVF/ICSI-ET cycle, resulting in a decrease of the number of retrieved oocytes and the number of embryo cryopreserved, but do not influence clinical pregnancy outcome. Ovarian reserve is impaired more seriously by cystectomy for ovarian endometriosis cyst than other ovarian benign cyst.

[Stereotactic brain biopsy guided by iMRI co-registration combined with PET/CT]

OBJECTIVE

To explore the clinical value of intraoperative magnetic resonance imaging (iMRI) coregistration combined with position emission tomography/computed tomography (PET/CT) in stereotactic brain biopsy.

METHODS

Forty nine patients with intracranial lesions were operated by stereotactic biopsy from June 2010 to June 2015 in Tianjin Medical University General Hospital. Seventeen patient's operation was guided by iMRI only (group A), thirty two patients' operation was guided by iMRI and PET/CT (group B). The diagnosis success rate and operation related complications were compared between the two groups.

RESULTS

PET/CT and iMRI were integrated successfully in all cases of group B. Fourteen patients (82.4%) of group A and all 32 patients (100%) of group B had final diagnosis confirmed by histopathological and immunohistochemical observation. The diagnosis success rate of group B was higher than group A (P<0.05). There were 5 patients in total who had postoperative complication, 2 (11.8%) in group A and 3 (9.3%) in group B, but the difference was not statistically significant.

CONCLUSIONS

PET/CT based metabolic imaging can be automatically integrated with standard MRI guided stereotactic biopsy. Compared with iMRI only, the combined treatment improves diagnosis success rate without increasing complications; it's safe, and has high clinical efficacy.

Cloning and characterization of defense-related genes from Populus szechuanica infected with rust fungus Melampsora larici-populina

Characterization of defense-related genes is critical for breeding disease-resistant poplar varieties and for better management and control of leaf rust disease. In the present study, full-length cDNAs of five Populus szechuanica defense-related (PsDR) genes, pathogen-related protein 1 (PsPR1), β-1,3-glucanase (PsGns), thaumatin-like protein 1 (PsTLP1), thaumatin-like protein 2 (PsTLP2), and phenylalanine ammonia-lyase (PsPAL), were cloned from the leaves of P. szechuanica infected with Melampsora larici-populina (MLP). PsPR1 (728 bp), PsGns (1189 bp), PsTLP1 (929 bp), PsTLP2 (885 bp), and PsPAL (2586 bp) were predicted to encode 161, 347, 245, 225, and 711 amino acid residue-containing proteins with isoelectric points of 8.53, 4.96, 4.51, 7.32, and 5.87, respectively. Moreover, the deduced PsDR proteins displayed more than 90% similarity to proteins from other Populus species. In response to the avirulent isolate, Sb052, and the virulent isolate, Th053, of MLP, the expression of PsDR genes was rapidly up-regulated in the leaves of P. szechuanica, peaked at 2 or 7 days post-inoculation (dpi), with levels in the incompatible interaction being higher than those in the compatible interaction. Meanwhile, the expression of PsDR genes (except for PsGns) was also differentially up-regulated at 3, 7, or 18 dpi in the petioles of the infected leaves, leaves next to the inoculated leaves, and in the top buds of the infected plants, respectively, compared to that at 0 dpi. These results suggest that these PsDR genes could play distinctive roles in the defense response of poplar against rust infection.

[Effect of radiation dose and dose rate on pulmonary fibrosis in mice]

OBJECTIVE

To study the effect of radiation dose and dose rate on radiation-induced pulmonary fibrosis in mice.

METHODS

Twenty-four C57BL/6 mice were randomly divided into a control group (n=6) and an irradiation group(n=18). The irradiation group was further assigned to 3 subgroups according to the whole lung radiation with 15 Gy at 400 cGy/min, 20 Gy at 400 cGy/min and 20 Gy at 100 cGy/min, while the control group received sham-irradiation. All mice were scanned with computed tomograph (CT) 20 weeks post-irradiation, and then they were sacrificed and lung tissues were collected. H&E staining, sirius red staining, lung fibrosis scored and hydroxyproline content analysis were used to assess lung fibrosis and collagen deposition. Real time PCR was used to measure the mRNA expression of type Ⅰ collagen. Immunohistochemical staining was used to detect the activatin and distribution of a-SMA(+) -myofibroblasts.

RESULTS

Compared to the control group, mice from irradiation groups exhibited significant pulmonary consolidation and collagen deposition.At the same dose rate, the higher irradiated dose used, the more severe pulmonary fibrosis was.On the other hand, with the same dose, the dose rate had less effect on pulmonary fibrosis.

CONCLUSION

The effect of radiation dose on the degree of pulmonary fibrosis in mice is more than effect of the dose rate.

Estimating sample size in the presence of competing risks – Cause-specific hazard or cumulative incidence approach?

In designing randomised clinical trials involving competing risks endpoints, it is important to consider competing events to ensure appropriate determination of sample size. We conduct a simulation study to compare sample sizes obtained from the cause-specific hazard and cumulative incidence (CMI) approaches, by first assuming exponential event times. As the proportional subdistribution hazard assumption does not hold for the CMI exponential (CMIExponential) model, we further investigate the impact of violation of such an assumption by comparing the results obtained from the CMI exponential model with those of a CMI model assuming a Gompertz distribution (CMIGompertz) where the proportional assumption is tenable. The simulation suggests that the CMIExponential approach requires a considerably larger sample size when treatment reduces the hazards of both the main event, A, and the competing risk, B. When treatment has a beneficial effect on A but no effect on B, the sample sizes required by both methods are largely similar, especially for large reduction in the main risk. If treatment has a protective effect on A but adversely affects B, then the sample size required by CMIExponential is notably smaller than cause-specific hazard for small to moderate reduction in the main risk. Further, a smaller sample size is required for CMIGompertz as compared with CMIExponential. The choice between a cause-specific hazard or CMI model in competing risks outcomes has implications on the study design. This should be made on the basis of the clinical question of interest and the validity of the associated model assumption.

Development of esophageal cancer in Chaoshan region, China: association with environmental, genetic and cultural factors

Esophageal squamous cell carcinoma (ESCC) is the eighth most common cancer by incidence worldwide. Although the cancer is located at a readily recognizable and accessible site in the body, it is the sixth most common cause of cancer death. The 1- and 5-year survival rates in China are 50% and 15%, respectively. Furthermore, the cancer has distinct geographic and etiological risk factors in different locations around the world. Since ESCC is highly prevalent in the Chaoshan (Southeastern) region of China, this report will focus on a review of risk factors for the cancer in this area. From the review, it is clear that some important and traditional factors are involved, e.g. environmental mutagens, genetic predisposition. However, unique factors, e.g. the drinking of very hot tea, may play an important role. This review highlights the role of complex risk factors (environmental, genetic and cultural) which contribute to the multistage development of cancer: localized injury, inflammation, mitogenesis, mutagenesis, carcinogenesis and eventually mortality. The latter is contributed by unnecessary delay in seeking medical care which may be culturally related. The review emphasizes the need to identify causal mechanisms for the complex carcinogenic process which can provide opportunity for prevention and treatment of this potentially curable cancer.

Design of the radiation shielding for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

A radiation shielding has been designed to reduce scattered neutrons and background gamma-rays for the new double-ring Time Of Flight Enhanced Diagnostics (TOFED). The shielding was designed based on simulation with the Monte Carlo code MCNP5. Dedicated model of the EAST tokamak has been developed together with the emission neutron source profile and spectrum; the latter were simulated with the Nubeam and GENESIS codes. Significant reduction of background radiation at the detector can be achieved and this satisfies the requirement of TOFED. The intensities of the scattered and direct neutrons in the line of sight of the TOFED neutron spectrometer at EAST are studied for future data interpretation.

Light output function and assembly of the time-of-flight enhanced diagnostics neutron spectrometer plastic scintillators for background reduction by double kinematic selection at EAST

The 2.5 MeV neutron spectrometer TOFED (Time-Of-Flight Enhanced Diagnostics) has been constructed to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas on EAST. The instrument has a double-ring structure which, in combination with pulse shape digitization, allows for a dual kinematic selection in the time-of-flight/recoil proton energy (tof/Ep) space, thus improving the spectrometer capability to resolve fast ion signatures in the neutron spectrum, in principle up to a factor ≈100. The identification and separation of features from the energetic ions in the neutron spectrum depends on the detailed knowledge of the instrument response function, both in terms of the light output function of the scintillators and the effect of undesired multiple neutron scatterings in the instrument. This work presents the determination of the light output function of the TOFED plastic scintillator detectors and their geometrical assembly. Results from dedicated experiments with γ-ray sources and quasi-monoenergetic neutron beams are presented. Implications on the instrument capability to perform background suppression based on double kinematic selection are discussed.

Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

Data acquisition system with pulse height capability for the TOFED time-of-flight neutron spectrometer

A new time-of-flight neutron spectrometer TOFED has been constructed for installation at Experimental Advanced Superconducting Tokamak. A data acquisition system combining measurements of flight time and energy from the interaction of neutrons with the TOFED scintillators has been developed. The data acquisition system can provide a digitizing resolution better than 1.5% (to be compared with the >10% resolution of the recoil particle energy in the plastic scintillators) and a time resolution <1 ns. At the same time, it is compatible with high count rate event recording, which is an essential feature to investigate phenomena occurring on time scales faster than the slowing down time (≈100 ms) of the beam ions in the plasma. Implications of these results on the TOFED capability to resolve fast ion signatures in the neutron spectrum from EAST plasmas are discussed.

Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall

To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 (3)He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated "experimental" result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the "experimental" measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

First Report of Cylindrocarpon destructans var. destructans Causing Black Root Rot of Sanqi (Panax notoginseng) in China

Sanqi (Panax notoginseng (Burk.) F. H. Chen) is planted on >10,000 ha in China and is a popular Chinese medicinal material (2). Black root rot is a recently identified but worsening problem on Sanqi since 2010 in Wenshan, China. Of the plant tubers examined from 185 ha, 8.5 to 27.4% were black with necrotic lesions. The base of leaves of infected plants had brown, sunken, necrotic lesions, and symptomatic plants had one to three chlorotic leaves. A fungus was isolated consistently from the basal leaves, bulb, and tubers of symptomatic plants. Six single-spore isolates were cultured on potato sucrose agar (PSA) at 25 ± 1°C in the dark. The mycelium of each culture was white initially on PSA, and then became rust-colored. The adaxial surfaces of the plates were black. Conidiophores were 13.6 to 167.3 × 1.4 to 21.8 μm (avg. 68.6 × 2.9 μm), single or with up to four levels of branching and two to three branches (or phialides) per level. The basal branches were often divergent, whereas the terminal branches were usually more appressed. Sporodochia were not present. Microconidia were 0-septate, 4.1 to 9.5 × 2.7 to 4.1 μm (avg. 8.2 × 2.9 μm). Conidia were 1- to 3-septate and occasionally 4-septate. One- to 3-septate conidia were clavate, with a truncate or slightly protruding conidial base, 9.2 to 40.8 × 3.5 to 6.8 μm (avg. 26.7 × 5.2 μm); whereas 4-septate conidia were 32.6 to 50.3 × 5.4 to 6.8 μm (avg. 40.9 × 6.5 μm). Chlamydospores were abundant, golden to brown, single or in chains or clumps, and up to 21.8 μm in diameter. PCR amplification was carried out for one isolate, RR926, using rDNA internal transcribed spacer (ITS) primer pairs ITS1F and ITS4 (4). Sequencing of the PCR product (GenBank Accession No. KC904953) revealed 99% similarity (99% coverage) with the ITS sequence of Cylindrocarpon destructans var. destructans (AM419065). Phylogenetic analysis (MEGA 4.1) using the neighbor-joining algorithm placed the isolate in a well-supported cluster (>90% bootstrap value based on 1,000 replicates) with AM419065. Therefore, the pathogen was identified as C. destructans (Zinssm.) Scholten var. destructans (teleomorph Ilyonectria radicicola (Gerlach & L. Nilsson) P. Chaverri & C. Salgado) based on morphological characteristics and rDNA-ITS sequence analysis (1,3). Pathogenicity tests of the six isolates were conducted on five 1-year-old and five 3-year-old plants/isolate. The roots of all plants were washed with sterilized water, and then surface-sterilized with 75% ethanol. Inoculum (1 ml of 10⁶ conidia/ml) of each isolate was brushed onto the roots of each plant with a paintbrush. Inoculated plants were planted in pots in a mixture of sterilized quartz sand:vermiculite:pearlite (2:1:1, v/v). The pots were placed under black shadecloth. The roots of five 1-year-old and five 3-year-old plants were brushed similarly with sterilized water as control treatments. After 30 days, symptoms similar to those on the original diseased plants were observed on the roots of all plants inoculated with the six isolates. The roots of non-inoculated plants remained healthy. The experiment was repeated. The same pathogen was re-isolated from the inoculated plants, but no pathogen was isolated from roots of the control plants. C. destructans var. destructans is widely distributed in soils (1), but to our knowledge, this is the first report of this fungus causing black root rot of Sanqi in China. References: (1) P. Charerri et al. Stud. Mycol. 68:57, 2011. (2) C. Y. Hu. New Rural Technol. 2:59, 2013 (in Chinese). (3) K. A. Seifert and P. E. Axelrood. Can. J. Plant Pathol. 20:115, 1998. (4) K. A. Seifert et al. Phytopathology 93:1533, 2003.

Urethane suppresses renal sympathetic nerve activity in Wistar rats

AIM

To investigate the effects of urethane on renal sympathetic nerve activity (RSNA) in Wistar rats.

MATERIALSAND METHODS

46 rats were randomly allocated in two groups: group A in which rats were injected with urethane; group B in which barbital sodium was used as a control. The changes of RSNA, blood pressure (BP) and heart rate (HR) of each group were evaluated and analyzed.

RESULTS

Compared to the control group, the value of RSNA, BP and HR were all significant decreased in rats of group A after urethane injection (p < 0.05).

CONCLUSIONS

These results suggest that urethane could affect RSNA through somatosensory system.

Comparison of 16S rRNA gene PCR and blood culture for diagnosis of neonatal sepsis

Septicemia is a common cause of morbidity and mortality among newborns in the developing world. However, accurate clinical diagnosis of neonatal sepsis is often difficult because symptoms and signs are often nonspecific. Blood culture has been the gold standard for confirmation of the diagnosis. However, the sensitivity is low and results are usually not promptly obtained. Therefore, the diagnosis of sepsis is often based on clinical signs in association with laboratory tests such as platelets count, immature/total neutrophils ratio (I/T), and a rise in C-reactive protein (CRP). Polymerase chain reaction (PCR) methods for the detection of neonatal sepsis represent new diagnostic tools for the early identification of pathogens.

METHODS

During a 4-month prospective study, 16S rRNA PCR was compared with conventional blood culture for the diagnosis of neonatal bacterial sepsis. In addition, the relationship between known risk factors, clinical signs, laboratory parameters, and the diagnosis of sepsis was considered.

RESULTS

Sepsis was suspected in 706 infants from the intensive neonatal care unit. They all were included in the study. The number of positive cultures and positive PCR results were 95 (13.5%) and 123 (17.4%), respectively. Compared with blood culture, the diagnosis of bacterial sepsis by PCR revealed a 100.0% sensitivity, 95.4% specificity, 77.2% positive predictive value, and 100.0% negative predictive value. In this study, Apgar scores at 5 min, weight, icterus, irritability, feeding difficulties, gestational age (GA), premature rupture of membrane (PRM), platelets count, I/T, and a marked rise in CRP were important in establishing the diagnosis of sepsis in the newborn. In addition, weight, GA, PRM, irritability, duration of antibiotic usage, mortality rate, and number of purulent meningitis cases were significantly different between early-onset sepsis and late-onset sepsis.

CONCLUSION

16S rRNA PCR increased the sensitivity in detecting bacterial DNA in newborns with signs of sepsis, allowed a rapid detection of the pathogens, and led to shorter antibiotic courses. However, uncertainty about the bacterial cause of sepsis was not reduced by this method. 16S rRNA PCR needs to be further developed and improved. Blood culture is currently irreplaceable, since pure isolates are essential for antimicrobial drug susceptibility testing.

Interspecies difference of luteolin and apigenin after oral administration of Chrysanthemum morifolium extract and prediction of human pharmacokinetics

The aims of the present study were to study the interspecies difference in the pharmacokinetics of luteolin and apigenin occurring in Chrysanthemum morifolium extract (CME) among rats, beagle dogs, mini-pigs, and humans, and compared the human pharmacokinetic parameters with the data predicted from the above three animals. The plasma concentrations of luteolin and apigenin were determined with a RP-HPLC method. An interspecies difference of pharmacokinetics was found, especially between rats and other species, the plasma concentration of luteolin was much lower than that of apigenin in rats, although the content of luteolin in CME was higherthan that of apigenin, whereas the plasma concentration of luteolin was much higher than that of apigenin in dogs, mini-pigs and humans. Animal scale-up of some pharmacokinetic parameters of luteolin and apigenin were also performed after rats, beagle dogs, mini-pigs and humans were orally given CME at dosages of 400 mg/kg, 102 mg/kg, 90 mg/kg, and 20 mg/kg, respectively. Linear relationships were obtained between log mean retention time (MRT) and log species body weight (W) (kg), and log elimination half-life (t1/2) (h) and logW. The corresponding allometric equations were MRT=9.382W(0.1711) (R2 = 0.9999) and t1/2 = 4.811W(0.1093) (R2 = 0.9013) for luteolin, MRT = 12.53W(0.0356) (R2 = 0.9980) and t1/2 = 7.940W(0.0294) (R2 = 0.9258) for apigenin, respectively. The predicted human pharmacokinetic parameters (MRT and t1/2) by an allometric approach were 18.6 h and 7.46 h for luteolin, 14.3 h and 8.95 h for apigenin, respectively, which were close to the values obtained from humans (20 mg CME/kg) in the present study. The study has demonstrated the possibility to extrapolate the pharmacokinetic behavior of flavonoids from animals to humans.

[Species-area and species-abundance relationships of arthropod community in various vegetation restoration areas in Zhifanggou watershed, Shaanxi province of Northwest China]

Taking the Zhifanggou watershed in Ansai, Shaanxi Province of Northwest China as a study unit, an investigation on the arthropods in 8 forest stands was conducted from 2006 to 2008, with the species-area and species-abundance relationships of the arthropods in these stands analyzed by various mathematical models. In these forest stands, the species-area relationship of the arthropods accorded with the formula S= CAm With the increase of investigation area, the species number approached to a constant, and the corresponding smallest investigation area was in the order of natural bush > natural forest > Populus davidiana+Robinia pseudoacacia forest > Hippaphae rhamnoides +Caragana mocrophylla forest> Periploca sepium forest > Hippaphae rhamnoides forest > Robinia pseudoacacia forest > Caragana mocrophylla forest, indicating that the more complex the stands, the larger the minimum area needed to be investigated. Based on sampling investigation, the species-abundance models of the arthropods in various stands were established. Lognormal distribution model (LN) was most suitable to fit the arthropod community in natural recovery stands, suggesting that in the arthropod community, there were more species with medial individual amount and fewer abundant species and rare species, and no obvious dominant species. LogCauchy distribution model (LC) was most suitable to fit the arthropod community in mixed and pure stands. As compared with natural recovery stand, mixed and pure stands had more abundant and rare species, and more dominant species.

Proteomic divergence in Arabidopsis autopolyploids and allopolyploids and their progenitors

Autopolyploidy and allopolyploidy are common in many plants and some animals. Rapid changes in genomic composition and gene expression have been observed in both autopolyploids and allopolyploids, but the effects of polyploidy on proteomic divergence are poorly understood. Here, we report quantitative analysis of protein changes in leaves of Arabidopsis autopolyploids and allotetraploids and their progenitors using isobaric tags for relative and absolute quantitation (iTRAQ) coupled with mass spectrometry. In more than 1000 proteins analyzed, the levels of protein divergence were relatively high (~18%) between Arabidopsis thaliana and Arabidopsis arenosa, relatively low (~6.8%) between an A. thaliana diploid and autotetraploid and intermediate (~8.3 and 8.2%) in F(1)- and F(8)-resynthesized allotetraploids relative to mid-parent values, respectively. This pattern of proteomic divergence was consistent with the previously reported gene expression data. In particular, many non-additively accumulated proteins (61-62%) in the F(1) and F(8) allotetraploids were also differentially expressed between the parents. The differentially accumulated proteins in functional categories of abiotic and biotic stresses were overrepresented between an A. thaliana autotetraploid and diploid and between two Arabidopsis species, but not significantly different between allotetraploids and their progenitors. Although the trend of changes is similar, the percentage of differentially accumulated proteins that matched previously reported differentially expressed genes was relatively low. Western blot analysis confirmed several selected proteins with isoforms the cumulative levels of which were differentially expressed. These data suggest high protein divergence between species and rapid changes in post-transcriptional regulation and translational modifications of proteins during polyploidization.

Lung Resistance Protein and Multidrug Resistance Protein in Non-Small Cell Lung Cancer and Their Clinical Significance

This study examined lung resistance protein (LRP) and multidrug resistance protein (MRP) in lung tumour tissue from 92 patients with non-small cell lung cancer (NSCLC) and normal lung tissue from 20 patients with benign lung tumours. The rates for LRP- and MRP-positive tumours among the NSCLC cases were 54% and 59%, respectively, and their combined positive rate was 45%. These rates were significantly higher than in normal lung tissue. The rates of LRP- and MRP-positive tumours were significantly higher among cases of adenocarcinoma than in cases of squamous cell carcinoma, and in highly differentiated tumours compared with tumours of low or moderate differentiation. There was a significant association between LRP- and MRP-positive tumours and a decrease in overall survival. In conclusion, LRP and MRP play a role in multidrug resistance in NSCLC and are related to prognosis in patients with NSCLC.

A novel coaxial tube catheter for central nervous system infusions: performance characteristics in brain phantom gel

We tested a novel neurocatheter in a brain-tissue gel model of drug infusion via convection-enhanced delivery (CED) for the treatment of a variety of neurological diseases. CED is an alternative to systemic administration of agents by intravenous or oral routes, which are often less effective or carry risk of systemic side effects. We investigated two co-axial tube devices, with outer diameters of 1.6 mm and 2.0 mm. Bromophenol blue dye was infused into 400 ml of 0.6% agarose gel at 1 μl/min for 1 h, with/without the inner and outer tubes Luer-locked at the proximal end, with/without the inner tube primed, and with/without the inner tube preloaded into the outer tube upon insertion into the gel. The unlocked, primed, and unloaded configuration produced infusions that resulted in significantly less (p < 0.05) entrapped air escaping into the gel and resulted in no reflux of infusate.

Numb regulates meiotic spindle organisation in mouse oocytes

Numb is an adaptor protein that controls the fate of cells in different species through asymmetrical inheritance by sibling cells during division. It has been investigated extensively in mitosis, mostly in neural progenitor cells, but its function in meiosis remains unknown. The present study was designed to investigate the expression, subcellular localisation and functional roles of Numb during mouse oocyte meiotic maturation. Using real-time polymerase chain reaction and western blotting, we found that the expression of Numb increased from the germinal vesicle (GV) to MII stages. Immunofluorescent staining revealed that Numb was mainly concentrated in the GV before meiosis resumption, aggregated in the vicinity of the chromosomes after GV breakdown and then localised to the spindle poles from prometaphase I to MII. Nocodazole treatment resulted in spindle destruction and Numb diffusion into the cytoplasm. However, Numb appeared at the spindle poles again once the spindles had formed when nocodazole-treated oocytes were washed and cultured for spindle recovery. Depletion of Numb by RNA interference resulted in chromosome misalignment, spindle deformation and even doubled spindle formation. Our results suggest that Numb is critical for spindle organisation during mouse oocytes meiosis. The present study provides evidence of a new function for Numb in addition to its action as a cell fate-determining factor.

Microvessel density and expression of thrombospondin-1 in non-small cell lung cancer and their correlation with clinicopathological features

Microvessel density and thrombospondin-1 (TSP-1) expression were analysed in 42 non-small cell lung cancer (NSCLC) specimens and 40 normal lung tissue specimens using immunohistochemistry. Microvessel density was significantly higher and TSP-1 expression significantly lower in NSCLC tissue compared with normal tissue. Significantly lower levels of TSP-1 expression and higher microvessel densities were found in late-stage NSCLC compared with early-stage NSCLC, and in those with lymph node metastasis compared with those without metastasis. A statistically significant inverse correlation was observed between TSP-1 expression and microvessel density in squamous cell carcinoma but not in adenocarcinoma. These results suggest a close relationship between microvessel density and NSCLC tumour progress, and that a high expression of TSP-1 may play an important role in inhibiting tumour occurrence and development. The lack of correlation between microvessel density and TSP-1 expression in adenocarcinoma suggests that the mechanism of tumour inhibition by TSP-1 varies according to histological type.

Changes and effects of plasma arginine vasopressin in traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a common disease accompanied by chronic morbidity and mortality. The pathological mechanism and effective pharmacological treatments of TBI remain undetermined. It is suggested that AVP is involved in TBI. It is thus interesting to investigate the changes and effects of plasma AVP in clinical trials.

METHODS

The serum concentrations of AVP, serum electrolytes, and serum osmolarity in a total of 23 TBI patients were dynamically monitored (on admission, Day 1, Day 3, and Day 5). Relationship between AVP and severity of brain injury and functional outcome were evaluated, respectively.

RESULTS

The mean AVP serum concentrations in the TBI group were significantly higher than those recorded in the control (CTRL) group on intensive care unit (ICU) admission and Day 1 (p<0.05). On Day 3 and Day 5, the differences between those groups were not significant (p>0.05). The negative correlations were found between sodium and AVP (r=-0.35; p<0.05) and between osmolarity and AVP (r=-0.42; p<0.05). In poor outcome group, the mean AVP serum concentrations were significantly higher than in good outcome group and CTRL group (p<0.05). A statistically significant correlation was also found between AVP on ICU admission and the initial Glasgow Coma Scale (r=0.47; p<0.05).

CONCLUSION

We suggest that AVP is involved in the pathophysiology process of secondary brain damage after TBI. It seems that AVP antagonist is a promising target for the treatment of TBI, while further studies should be carried out.

Superconducting properties of the Fe-based layered superconductor LaFeAsO0.9F0.1-delta

We have employed a new route to synthesize single phase F-doped LaOFeAs compound and confirmed the superconductivity above 20 K in this Fe-based system. We show that the new superconductor has a rather high upper critical field of over 50 T. A clear signature of superconducting gap opening below T(c) was observed in the far-infrared reflectance spectra, with 2Delta/kT(c) approximately 3.5-4.2. Furthermore, we show that the new superconductor has electron-type conducting carriers with a rather low-carrier density.

Low-temperature electronic transport in single K(0.27)MnO(2)·0.5H(2)O nanowires: enhanced electron-electron interaction

The current-voltage (I-V) characteristics and electrical resistivity of isolated potassium manganese oxide (K(0.27)MnO(2)·0.5H(2)O) nanowires prepared by a simple hydrothermal method were investigated over a wide temperature range from 300 to 4 K. With lowering temperature, a transition from linear to nonlinear I-V curves was observed around 50 K, and a clear zero bias anomaly (i.e., Coulomb gap-like structure) appeared on the differential conductance (dI/dV) curves, possibly due to enhanced electron-electron interaction at low temperatures. The temperature dependence of resistivity, [Formula: see text], follows the Efros-Shklovskii (ES) law, as expected in the presence of a Coulomb gap. Here we note that both the ES law and Coulomb blockade can in principle lead to a reduced zero bias conductance at low temperatures; in this study we cannot exclude the possibility of Coulomb-blockade transport in the measured nanowires, especially in the low-temperature range. It is still an open question how to pin down the origin of the observed reduction to a Coulomb gap (ES law) or Coulomb blockade.

Ubiquitin-mediated activation of TAK1 and IKK

Transforming growth factor beta activated kinase-1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, has emerged as a key regulator of signal transduction cascades leading to the activation of the transcription factors nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1). Stimulation of cells with cytokines and microbial pathogens results in the activation of TAK1, which subsequently activates the I-kappa B kinase complex (IKK) and mitogen-activated protein (MAP) kinases, culminating in the activation of NF-kappaB and AP-1, respectively. Recent studies have shown that polyubiquitination of signalling proteins through lysine (Lys)-63-linked polyubiquitin chains plays an important role in the activation of TAK1 and IKK. Unlike Lys-48-linked polyubiquitination, which normally targets proteins for degradation by the proteasome, Lys-63-linked polyubiquitin chains act as scaffolds to assemble protein kinase complexes and mediate their activation through proteasome-independent mechanisms. The concept of ubiquitin-mediated activation of protein kinases is supported by the discoveries of ubiquitination and deubiquitination enzymes as well as ubiquitin-binding proteins that function upstream of TAK1 and IKK. Recent biochemical and genetic studies provide further insights into the mechanism and function of ubiquitin signalling and these advances will be the focus of this review.

Molecular marker genotypes, heterozygosity and genetic interactions explain heterosis in Arabidopsis thaliana

The underlying mechanisms for hybrid vigor or heterosis are elusive. Here we report a population of recombinant inbred lines (RILs), derived from the two ecotypes, Col and Ler, which can serve as a permanent resource for studying the molecular basis of hybrid vigor in Arabidopsis. Using a North Carolina mating design III (NCIII), we determined the additive and dominant nature of gene action in this population. We detected heterosis among crosses of RILs with one of the two parents (Col and Ler) and analyzed genotypes and heterozygosities for RILs and test cross families (RILs crossed to Col and Ler) using a total of 446 published molecular markers. The performance of RILs and additive and dominant components in the test cross families were used to analyze QTLs for 16 traits, using QTL cartographer and composite interval mapping with 1,000 permutations for each trait. Our data suggest that locus-specific and/or genome-wide differential heterozygosity, including epistasis, plays an important role in the generation of the observed heterosis. Furthermore, the hybrid vigor occurred between two closely related ecotypes, and provides a general mechanism for novel variation generated between genetically similar materials.

Effects of sucrose concentration on the developmental potential of human frozen–thawed oocytes at different stages of maturity

BACKGROUND

Success of human oocyte cryopreservation depends on multiple cryobiological factors that could influence the developmental potential of the oocytes. The objective of this study was to examine the effects of different sucrose concentrations on the developmental potential of human frozen-thawed oocytes at different maturity stages.

METHODS

A total of 355 oocytes collected from small follicles were randomly divided into three groups and two groups (B and C) were cryopreserved using slow-freezing method. Group A included 131 oocytes at different maturity stages without freezing. Another 119 oocytes in Group B were cryopreserved with 0.1 M sucrose and 105 oocytes in Group C with 0.2 M sucrose concentration.

RESULTS

The post-thaw survival rate of the oocytes and the cleavage rate in Group C were significantly higher than that of Group B (P<0.05). For immature metaphase I (MI) stage oocytes, a significant difference was found in the maturation rate between Group C and Group B (P<0.05). The maturation rate for the GV oocytes in Groups A and C was significantly higher than Group B (P<0.01).

CONCLUSIONS

The results suggested that sucrose concentration of 0.2 M in the cryoprotectant solution is more suitable for human oocyte cryopreservation.