Engineering a single ubiquitin ligase for the selective degradation of all activated ErbB receptor tyrosine kinases

Interrogating specific cellular activities often entails the dissection of posttranslational modifications or functional redundancy conferred by protein families, which demands more sophisticated research tools than simply eliminating a specific gene product by gene targeting or RNA interference. We have developed a novel methodology that involves engineering a single SCF(βTrCP)-based ubiquitin ligase that is capable of not only simultaneously targeting the entire family of ErbB receptor tyrosine kinases for ubiquitination and degradation, but also selectively recruiting only activated ErbBs. The engineered SCF(βTrCP) ubiquitin ligase effectively blocked ErbB signaling and attenuated oncogenicity in breast cancer cells, yet had little effect on the survival and growth of non-cancerous breast epithelial cells. Therefore, engineering ubiquitin ligases offers a simple research tool to dissect the specific traits of tumorigenic protein families, and provides a rapid and feasible means to expand the dimensionality of drug discovery by assessing protein families or posttranslational modifications as potential drug targets.

Serum N-terminal pro-brain natriuretic peptide level is a significant prognostic factor in patients with severe sepsis among Southwest Chinese population

BACKGROUND

This study aimed to determine the predictive value of elevated N-terminal pro-brain natriuretic peptide (NTproBNP) for mortality in patients with severe sepsis.

PATIENTS AND METHODS

This was a retrospective study in Emergency Department of Sichuan Provincial People's Hospital, and patients were screened between January 1, 2009 and December 31, 2011. Demographic and clinical data as well as Acute Physiology And Chronic Health Evaluation II (APACHE II) and Sepsis Organ Failure Assessment (SOFA) scores were collected within the first day of admission. Survival was determined to establish its association with the NT-proBNP using logistic regression and receiver operating characteristic (ROC) curve.

RESULTS

A total of 171 patients with severe sepsis were analyzed. The median APACHE IIⅡ and SOFA scores were 11 (IQR, 7-16) and 3 (IQR, 1-5), respectively. The median C-reactive protein (CRP), procalcitonin (PCT) and NT-proBNP was 10.3 mg/dL (IQR, 3.4-21.4 mg/dL), 0.4 ng/mL (IQR, 0.2-3.6 ng/mL), and 954 (321-1576) pg/mL, respectively. The median NT-proBNP in survivors was 584 pg/mL (IQR, 321-875 pg/mL) versus 1271 (IQR, 851-1576 pg/mL) in nonsurvivors (p < 0.001). In the ROC curves, the area value was 0.89 for serum NT-proBNP, and its potent cutoff value was 1500 pg/mL. After multivariate regression analysis, NT-proBNP was significantly correlated with the mortality of severe sepsis (OR = 1.58, 95% CI 1.36-1.77).

CONCLUSIONS

Serum NT-proBNP is frequently increased in severe sepsis patients, and non-survivors have higher levels than survivors. High levels of admission NT-proBNP are associated with mortality.

The Cul4A-DDB1 E3 ubiquitin ligase complex represses p73 transcriptional activity

The Cullin4A (cul4A)-dependent ligase (CDL4A) E3 has been implicated in a variety of biological processes, including cell cycle progression and DNA damage response. Remarkably, CDL4A exerts its function through both proteolytic and non-proteolytic events. Here, we show that the p53 family member p73 is able to interact with the CDL4A complex through its direct binding to the receptor subunit DNA-binding protein 1 (DDB1). As a result, the CDL4A complex is able to monoubiquitylate p73. Modification of p73 by CDL4A-mediated ubiquitylation does not affect p73 protein stability, but negatively regulates p73-dependent transcriptional activity. Indeed, genetic or RNA interference-mediated depletion of DDB1 induces the expression of several p73 target genes in a p53-independent manner. In addition, by exploiting a bioinformatic approach, we found that elevated expression of Cul4A in human breast carcinomas is associated with repression of p73 target genes. In conclusion, our findings add a novel insight into the regulation of p73 by the CDL4A complex, through the inhibition of its transcriptional function.

[A study on immunity enhancement of frozen human lung cancer cells in vitro.]

BACKGROUND

To investigate the mechanisms of cryo-immunotherapeutic effect.

METHODS

After the mixed culture of human lung cancer cells and autologous lymphocytes was conducted in vitro ,lymphocyte transformation rate (LTR) , soluble interleukin-2 receptor (SIL-2R) and interleukin-6 ( IL-6) in the supernatants of the frozen lung cancer cells and the control were detected. Meanwhile , the effects of the supernatants of the culture of frozen lung cancer cells and the control on the proliferation of autologous lung cancer cells were also determined with FCM measurement.

RESULTS

(1)The levels of SIL-2R , IL-6 and LTR in the group of frozen lung cancer cells were all highly significant higher than those in the group of the control ( P < 0. 01) . (2)The supernatant of the culture of the frozen lung cancer cells could remarkably inhibit the proliferation of the autologous lung cancer cells ( P < 0. 01) .

CONCLUSIONS

(1)Frozen lung cancer cells may improve the immune function of lymphocytes through promoting their activation , proliferation and secretion of cytokines. (2)The activation of immune competent cells by freezing can remarkably inhibit the proliferation of lung cancer cells. Therefore , freezing can irritate the body's anti-tumor immunity.

Dendritic cell-derived tumor necrosis factor α modifies airway epithelial cell responses

Mucosal dendritic cells (DC) are intimately associated with the airway epithelium and thus are ideally situated to be first responders to pathogens. We hypothesize that DC drive innate immune responses through early release of tumor necrosis factor (TNF) α, which drives airway epithelial cell responses. In a mouse model, TNFα release was significantly increased following a single exposure to German cockroach (GC) frass, an event independent of neutrophil recruitment into the airways. While lung epithelial cells and alveolar macrophages failed to release TNFα following GC frass exposure, bone marrow-derived DC (BMDC) produced substantial amounts of TNFα suggesting their importance as early responding cells. This was confirmed by flow cytometry of pulmonary myeloid DC. Addition of GC frass-pulsed BMDC or conditioned media from GC frass-pulsed BMDC to primary mouse tracheal epithelial cells (MTEC) or MLE-15 cells induced chemokine (C-C) motif ligand (CCL) 20 and granulocyte macrophage (GM) colony-stimulating factor (CSF), both of which are important for DC recruitment, survival and differentiation. Importantly, DC do not produce CCL20 or GM-CSF following allergen exposure. Blocking TNFα receptor 1 (TNFR1) completely abolished chemokine production, suggesting that BMDC-derived TNFα induced airway epithelial cell activation and enhancement of the innate immune response. Lastly, blocking TNFR1 in vivo resulted in significantly decreased CCL20 and GM-CSF production in the lungs of mice. Together, our data strongly suggest that DC-derived TNFα plays a crucial role in the initiation of innate immune responses through the modification of airway epithelial cell responses.

Hypoglycemic effect and mechanism of a proteoglycan from ganoderma lucidum on streptozotocin-induced type 2 diabetic rats

BACKGROUND AND OBJECTIVES

Diabetes mellitus inducing a leading cause of morbidity are widespread in the entire globe. The present study was to investigate the antidiabetic potency and mechanism of a proteoglycan extract, named FYGL (Fudan-Yueyang-G. lucidum), from the fruiting bodies of Ganoderma Lucidum as published recently, using streptozotocin-induced type 2 diabetic mellitus (T2DM) rats.

MATERIAL AND METHODS

The T2DM model rats were treated with FYGL as well as metformin and rosiglitazone. The levels of plasma glucose and insulin were measured, and the expression and activity of the protein tyrosine phosphatase 1B (PTP1B) and the tyrosine phosphorylation level of the insulin receptor (IR) 3-subunit in the livers and skeletal muscles of the T2DM rats were analyzed by immunoprecipitation and Western blotting methods. In addition, the levels of free fatty acid and serum lipid profile were measured using commercial kits for those trailed rats.

RESULTS

The decrease in fasting plasma glucose and the increase in insulin concentration dose- and time-dependently in the T2DM rats treated by FYGL, comparable with that by the clinical drugs, metformin and rosiglitazone. The levels of the PTP1B expression and activity were decreased, and the tyrosine phosphorylation level of the IR 1-subunit was increased in the skeletal muscles of the T2DM rats. Furthermore, FYGL significantly decreased the levels of free fatty acid, triglyceride, total cholesterol and low density lipoprotein-cholesterol as well as increased the level of high density lipoprotein-cholesterol.

DISCUSSION

It is suggested that the hypoglycemic mechanisms of FYGL are caused by inhibition of the PTP1B expression and activity, consequently, regulation of the tyrosine phosphorylation level of the IR 13-subunit. As those results, FYGL also controlled the plasma biochemistry indexes relative to the type 2 diabetes-accompanied metabolic disorders. This is possibly the first report on the underlying mechanisms responsible for the antidiabetic effect of Ganoderma lucidum.

The association between bacterial colonization and inflammatory pattern in Chinese chronic rhinosinusitis patients with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) can be subdivided according to the mucosal inflammatory patterns. In mainland China, apart from interleukin (IL)-5-positive and IL-17-positive polyps, a large group of patients with IL-5/IL-17/interferon-gamma (IFNγ)-negative nasal polyps (referred to as key cytokine-negative (KCN) polyps) can be found.

OBJECTIVE

To further study the KCN polyps and evaluate the associations between bacterial colonization and mucosal inflammatory pattern in KCN vs IL-5-positive nasal polyps.

METHODS

Nasal polyp or nasal turbinate tissue was obtained from 89 Chinese CRSwNP patients and 36 nonatopic control subjects during surgery. Samples without and after SEB exposure were processed for the assessment of pro-inflammatory cytokines and mediators by immunoassay. Prior to surgery, nasal swabs were taken from each patient for microbiological evaluation.

RESULTS

Overall, 80% polyp tissue did not express IL-5, with about 70% (49/71) of these being KCN. Key cytokine-negative nasal polyps were characterized by the synthesis of mediators promoting neutrophilic inflammation (myeloperoxidase (MPO), IL-1β, IL-6 and IL-8), whereas IL-5-positive nasal polyps were characterized by the synthesis of mediators promoting eosinophilic inflammation (IL-5, ECP, total IgE and SE-IgE). Key cytokine-negative nasal polyps were associated with greater Gram-negative bacterial load compared with controls, while IL-5-positive nasal polyps were associated with greater Gram-positive bacterial colonization vs controls and KCN polyps.

CONCLUSION

Our findings suggest that the bacteria colonizing nasal polyps of CRSwNP patients may impact on or be determined by the presence/absence of IL-5.

Search for CP violation in τ±→K(S)0π±ντ decays at Belle

We report on a search for CP violation in τ(±)→K(S)(0)π(±)ν(τ) decays using a data sample of 699 fb(-1) collected by the Belle experiment at the KEKB electron-positron asymmetric-energy collider. The CP asymmetry is measured in four bins of the invariant mass of the K(S)(0)π(±) system and found to be compatible with zero with a precision of O(10(-3)) in each mass bin. Limits for the CP violation parameter Im(η(S)) are given at the 90% confidence level. These limits are |Im(η(S))| < 0.026 or better, depending on the parametrization used to describe the hadronic form factors, and improve upon previous limits by 1 order of magnitude.

Observation of X(3872)→J/ψγ and search for X(3872)→ψ'γ in B decays

We report a study of B→(J/ψγ)K and B→(ψ'γ)K decay modes using 772×10⁶ B ̅B events collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We observe X(3872)→J/ψγ and report the first evidence for χ(c2)→J/ψγ in B→(X_{c ̅cγ)K decays, while in a search for X(3872)→ψ'γ no significant signal is found. We measure the branching fractions, B(B(±)→X(3872)K(±))B(X(3872)→J/ψγ)=(1.78(-0.44)(+0.48)±0.12)×10(-6), B(B(±)→χ(c2)K(±))=(1.11(-0.34)(+0.36)±0.09)×10(-5), B(B(±)→X(3872)K(±))B(X(3872)→ψ'γ)<3.45×10⁶ (upper limit at 90% C.L.), and also provide upper limits for other searches.

Observation of transverse polarization asymmetries of charged pion pairs in e+e- annihilation near √s = 10.58 GeV

The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e(+)e(-) annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π(+)π(-) pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672 fb(-1) data sample that contains 711 × 10(6) π(+)π(-) pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider.

Observation of the h(c)(1P) Using e+ e- collisions above the DD threshold

Using 586  pb(-1) of e+ e- collision data at E(c.m.) = 4170  MeV, produced at the Cornell Electron Storage Ring collider and collected with the CLEO-c detector, we observe the process e+ e- → π+ π- h(c)(1P). We measure its cross section to be 15.6±2.3±1.9±3.0  pb, where the third error is due to the external uncertainty on the branching fraction of ψ(2S) → π0 h(c)(1P), which we use for normalization. We also find evidence for e+ e- → ηh(c)(1P) at 4170 MeV at the 3σ level and see hints of a rise in the e+ e- → π+ π- h(c)(1P) cross section at 4260 MeV.

Numerical simulation of microneedles' insertion into skin

Microneedles have recently received much attention as a novel way for transdermal drug delivery. In this paper, a numerical simulation of the insertion process of the microneedle into human skin is reported using the finite element method. A multilayer skin model consisting of the stratum corneum, dermis and underlying hypodermis has been developed. The effective stress failure criterion has been coupled with the element deletion technique to predict the complete insertion process. The numerical results show a good agreement with the reported experimental data for the deformation and failure of the skin and the insertion force. The influences of the mechanical properties of the skin and the microneedle geometry (e.g. tip area, wall angle and wall thickness) on the insertion force are discussed. The numerical results are helpful for the optimum design of the microneedles for the transdermal drug delivery system.

Ursolic acid promotes robust tolerance to cardiac allografts in mice

Nuclear factor (NF)-κB is an important molecule in T cell activation. Our previous work has found that T cell-restricted NF-κB super-repressor (IκBαΔN-Tg) mice, expressing an inhibitor of NF-κB restricted to the T cell compartment, can permanently accept fully allogeneic cardiac grafts and secondary donor skin grafts. In this study, we explore if transient NF-κB inhibition by a small molecular inhibitor could induce permanent graft survival. Ursolic acid, a small molecular compound, dose-dependently inhibited T cell receptor (TCR)-triggered NF-κB nuclear translocation and T cell activation in vitro. In vivo, ursolic acid monotherapy prolonged significantly the survival of cardiac allograft in mice. Assisted with donor-specific transfusion (DST) on day 0, ursolic acid promoted 84·6% of first cardiac grafts to survive for more than 150 days. While the mice with long-term surviving grafts (LTS) did not reject the second donor strain hearts for more than 100 days without any treatment, they all promptly rejected the third-party strain hearts within 14 days. Interestingly, this protocol did not result in an increased proportion of CD4(+) CD25(+) forkhead box P3(+) regulatory T cells in splenocytes. That adoptive transfer experiments also did not support regulation was the main mechanism in this model. Splenocytes from LTS showed reduced alloreactivity to donor antigen. However, depletion of CD4(+) CD25(+) regulatory T cells did not alter the donor-reactivity of LTS splenocytes. These data suggest that depletion of donor-reactive T cells may play an important role in this protocol.

Observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370)

We report the observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370), which are CP eigenstate decay modes. These results are obtained from 121.4 fb⁻¹ of data collected at the Υ(5S) resonance with the Belle detector at the KEKB e(+)e⁻ collider. We measure the branching fractions B(B(s)⁰→J/ψf₀(980); f₀(980)→π(+)π⁻)=(1.16(-0.19)(+0.31)(stat)(-0.17)(+0.15)(syst)(-0.18)(+0.26)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 8.4σ, and B(B(s)⁰→J/ψf₀(1370); f₀(1370)→π(+)π⁻)=(0.34(-0.14)(+0.11)(stat)(-0.02)(+0.03)(syst)(-0.05)(+0.08)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 4.2σ. The last error listed is due to uncertainty in the number of produced B(s)((*))B(s)((*)) pairs.

Double Layered HA Coating, its Characterization and Preparation

Hydroxyapatite (HA) has been universally used because of good biocompatibility. There are varieties of coating methods, however, they still have problems. The most significant problem is layer thickness. We introduced a new coating procedure to eliminate this difficulty.

The characterization of the coating was studied by X-ray diffractometry, infrared spectroscopy, SEM and chemical analysis. Said examination indicated that the double layer consisted of carbonate HA and CaTiO3 and the thickness of the layer was 2-4 μm. The coating was performed on the inner surfaces of 50-200 μm sized pores and was also consistent in the smallest of the pores even those of 50 μm. Our results indicated that the coating layer was homogeneous and thin. In addition, both layers consisted of Ca ions. The consistency of coating into even the smallest pore size suggested that our method promises to have widespread clinical applications in artificial implants because of increased surface contact area.

First measurement of inclusive B→Xsη decays

We report a first measurement of inclusive B→Xsη decays, where Xs is a charmless state with unit strangeness. The measurement is based on a pseudoinclusive reconstruction technique and uses a sample of 657×10(6)BB pairs accumulated with the Belle detector at the KEKB e+e- collider. For MXs < 2.6 GeV/c2, we measure a branching fraction of [26.1±3.0(stat)-2.1+1.9(syst)-7.1+4.0(model)]×10(-5) and a direct CP asymmetry of ACP=-0.13±0.04-0.03+0.02. Over half of the signal occurs in the range MXs > 1.8 GeV/c2.

Basiliximab or antithymocyte globulin for induction therapy in kidney transplantation: a meta-analysis

OBJECTIVE

To compare efficacy and safety of basiliximab versus antithymocyte globulin (ATG) for induction therapy in kidney transplantation.

METHODS

A literature search of the MEDLINE, EMBASE, CBMdisc, and Cochrane databases was used to identify randomized controlled trials that compared basiliximab and ATG for induction therapy in kidney transplantation. Inclusion criteria comprised: prospective randomized controlled clinical trials, follow-up time >or=12 months, randomized comparisons of ATG versus basiliximab as induction therapy in kidney transplantation. Meta-analytical techniques were applied to identify differences in outcomes between the two agents.

RESULTS

A total of six studies involving 853 patients were identified. No differences between ATG and basiliximab were seen in terms of biopsy-proven rejection (relative risk [RR] 1.15, 95% confidence interval [CI] 0.88-1.52, P = .31), delayed graft function (RR 1.02, 95% CI 0.69-1.51, P = .93), graft loss (RR 1.15, 95% CI 0.73-1.80, P = .55), and patient death (RR 1.22, 95% CI 0.65-2.30, P = .54). But basiliximab had a lower incidence of infection (RR 0.87, 95% CI 0.78-0.97, P = .02) and neoplasm (RR 0.29, 95% CI 0.09-0.97, P = .04).

CONCLUSIONS

Basiliximab is as effective as ATG for induction therapy in kidney transplantation, whereas basiliximab has a lower incidence of infection. Basiliximab may be a safer and preferable option for induction therapy in kidney transplantation.

Protein interaction matrix of Papaya ringspot virus type P based on a yeast two-hybrid system

Comprehensive analysis of the interactions between 10 mature proteins of Papaya ringspot virus type P (PRSV-P) was carried out based on a yeast two-hybrid system assay (YTHS). We detected 6 interactions between different viral proteins (VPg-P1, VPg-P3, VPg-CI, VPg-CP, NIaPro-CI, and NIb-P3) and 4 self-interactions (HC-Pro, VPg, NIaPro, and CP). These interactions did not show the same directionality as corresponding interactions detected in other potyviruses and consequently, a protein interaction matrix displayed different patterns. This initial map of the protein interactions of PRSV-P allows further study of various viral proteins in order to develop anew strategy to control PRSV-P infection.

Cloning and expression analysis of phytoene desaturase and ζ-carotene desaturase genes in Carica papaya

The fruit flesh color of papaya is an important nutritional quality trait and is due to the accumulation of carotenoid. To elucidate the carotenoid biosynthesis pathway in Carica papaya, the phytoene desaturase (PDS) and the ζ-carotene desaturase (ZDS) genes were isolated from papaya (named CpPDS and CpZDS) using the rapid amplification of cDNA ends (RACE) approach, and their expression levels were investigated in red- and yellow-fleshed papaya varieties. CpPDS contains a 1749 bp open reading frame coding for 583 amino acids, while CpZDS contains a 1716 bp open reading frame coding for 572 amino acids. The deduced CpPDS and CpZDS proteins contain a conserved dinucleotide-binding site at the N-terminus and a carotenoid-binding domain at the C-terminus. Papaya genome sequence analysis revealed that CpPDS and CpZDS are single copy; the CpPDS was mapped to papaya chromosome LG6, and the CpZDS was mapped to chromosome LG3. Quantitative PCR showed that both CpPDS and CpZDS were expressed in all tissues examined with the highest expression in maturing fruits, and that the expression of CpPDS and CpZDS were higher in red-fleshed fruits than in yellow-fleshed fruits. These results indicated that the differential accumulation of carotenoids in red- and yellow-fleshed papaya varieties might be partly explained by the transcriptional level of CpPDS and CpZDS.

The Role of T-Helper 17 (Th17) Cells in Patients with Medulloblastoma

As a new member of the CD4+ effector T-cell family, T-helper 17 (Th17) cells, have emerged as an important mediator in inflammatory and autoimmune diseases. Th17 cells preferentially produce interleukin (IL)-17A, IL-17F, IL-21, IL-22, and IL-26 in humans. Recent studies suggest a potential role for Th17 cells in tumour development. The current study was designed to investigate the possible involvement of Th17 cells in the brain tumour medulloblastoma. Compared with 17 healthy volunteers, 23 patients with medulloblastoma had a higher proportion of Th17 cells in their peripheral blood. Increased populations of Th17 cells were also present in medulloblastoma-infiltrating T-cells. Furthermore, the mRNA levels for Th17-related factors (IL-17, IL-23 and retinoid orphan nuclear receptor) in tumour tissues and the serum concentrations of IL-17 and IL-23 protein were significantly increased in patients with medulloblastoma. The results indicate that Th17 cells may contribute to medulloblastoma pathogenesis.

Stable expression of rice dwarf virus Pns10 suppresses the post-transcriptional gene silencing in transgenic Nicotiana benthamiana plants

RNA silencing is a conserved mechanism that defends against viral infection and retrotransposon activity for protection of the genome. Segment 10 (S10) of Rice dwarf virus (RDV) encodes Pns10 protein, a viral suppressor of RNAi that suppresses the host RNA silencing machinery. In this study, we obtained stable transgenic RDV-S10 Nicotiana benthamiana plants expressing Pns10. Suppression of post-transcriptional gene silencing (PTGS) by Pns10 supported the conclusion that this protein exhibited the RNA silencing suppressor activity. In particular, the transgenic plants stably expressing a viral suppressor of RNAi (VSR) provide a model system for investigating the mechanism of RNA silencing.

KEYWORDS

RNA silencing; VSR; Rice dwarf virus; Pns10; transgenic plant.

Deep subthreshold Xi;{-} production in Ar + KCl reactions at 1.76A GeV

We report first results on a deep subthreshold production of the doubly strange hyperon Xi;{-} in a heavy-ion reaction. At a beam energy of 1.76A GeV the reaction Ar + KCl was studied with the High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity Lambda sample was collected, allowing for the investigation of the decay channel Xi;{-} --> Lambdapi;{-}. The deduced Xi;{-}/(Lambda + Sigma;{0}) production ratio of (5.6 +/- 1.2_{-1.7};{+1.8}) x 10;{-3} is significantly larger than available model predictions.

Space charge effects in photoemission electron microscopy using amplified femtosecond laser pulses

Linear and nonlinear photoemission microscopy is used to study the origin of space charge effects that are frequently observed if amplified femtosecond lasers are used for generation of photoelectrons. Space charge effects are apparent in the width of the photoemission spectra, but also create image blur. The onset threshold for space charge effects is determined by recording the width of photoemission spectra and by finding the conditions under which spectral broadening is just less than the energy resolution of the microscope. The principal findings are independent if harmonics of the fundamental of the fs laser pulses are used, but the space charge effects are found to be more dominant at lower repetition rates. By inserting apertures into the electron path, the place at which space charge effects occur can be localized.

Survey on the function, structure and operation of hospital ethics committees in Shanghai

OBJECTIVE

The objectives of this study are to understand the current functions, structure and operation of hospital ethics committees (HECs) in Shanghai and to facilitate their improvement.

METHODS

(1) A questionnaire survey, (2) interviews with secretaries and (3) on-site document reviews of HECs in Shanghai were used in the study, which surveyed 33 hospitals.

RESULTS

In Shanghai, 57.56% of the surveyed hospitals established HECs from 1998 to 2005. Most HECs used bioethical review of research involving human subjects as well as bioethical review or consultation regarding medical care services and administrative decision- making. Of the surveyed HECs, 14.3% did not provide any formal bioethical training to the HECs' members and many HECs had no standard operating procedures. Some HECs had no clear definition of what was "conflict of interest" that should be considered by the HECs, while 44.4% of the HECs did not perform continuing review.

DISCUSSION

After the issues of related national regulations, more and more hospitals established HECs in Shanghai, but the functions of HECs need to be further developed and formal training on bioethics should be provided to HEC members. To assure the independence and good performance of HECs, the conflict of interest procedure, the standard operating procedures and bioethical review should be improved.

CONCLUSION

HECs in Shanghai had developed in the preceding 10 years and they played great roles in protecting the rights and welfare of human subjects and patients; some areas need improvement.

Optimized Kalpha x-ray flashes from femtosecond-laser-irradiated foils

We investigate the generation of ultrashort Kalpha pulses from plasmas produced by intense femtosecond p-polarized laser pulses on Copper and Titanium targets. Particular attention is given to the interplay between the angle of incidence of the laser beam on the target and a controlled prepulse. It is observed experimentally that the Kalpha yield can be optimized for correspondingly different prepulse and plasma scale-length conditions. For steep electron-density gradients, maximum yields can be achieved at larger angles. For somewhat expanded plasmas expected in the case of laser pulses with a relatively poor contrast, the Kalpha yield can be enhanced by using a near-normal-incidence geometry. For a certain scale-length range (between 0.1 and 1 times a laser wavelength) the optimized yield is scale-length independent. Physically this situation arises because of the strong dependence of collisionless absorption mechanisms-in particular resonance absorption-on the angle of incidence and the plasma scale length, giving scope to optimize absorption and hence the Kalpha yield. This qualitative description is supported by calculations based on the classical resonance absorption mechanism and by particle-in-cell simulations. Finally, the latter simulations also show that even for initially steep gradients, a rapid profile expansion occurs at oblique angles in which ions are pulled back toward the laser by hot electrons circulating at the front of the target. The corresponding enhancement in Kalpha yield under these conditions seen in the present experiment represents strong evidence for this suprathermal shelf formation effect.

Endoscopic decompression using a transanal drainage tube for acute obstruction of the rectum and left colon as a bridge to curative surgery

OBJECTIVE

The aim of this study was to clarify the usefulness of the management of acute left colon and rectum obstruction because of colorectal carcinoma using a transanal ileus drainage tube before curative surgery.

METHOD

Forty-six patients (24 males and 22 females, aged 24-94 years, mean = 56.2) treated between September 2005 and March 2007 for acute left colon and rectal obstruction were identified in a colorectal obstruction database, and their clinical and radiological features were reviewed. After a cleaning enema was administered, urgent colonoscopy was performed. Subsequently, endoscopic decompression using a ileus tube was attempted.

RESULTS

Endoscopic decompression using the ileus tube was technically successful in 45 of 46 patients (97.8%). Perforation occurred in one patient 3 days later and emergent operation was performed. The site of obstruction was the rectum in 15 patients, the sigmoid colon in 18, the descending colon in 13. Following adequate cleansing of the colon, patients' abdominal girth were decreased from 91 +/- 4 cm before drainage to 82 +/- 2 cm 7 days later, and one-stage surgery after 8 +/- 1 days (SD; range 7-10 days) were performed. No anastomotic leakage or postoperative stenosis occurred after operation.

CONCLUSION

Management of acute left colon and rectum obstruction because of colorectal carcinoma using the ileus tube was found to be effective and safe, considered as a bridged method before curative surgery.

Seroprevalence of Toxoplasma gondii infection in stray and household cats in Guangzhou, China

The prevalence of anti-Toxoplasma gondii specific IgG in stray and household cats in Guangzhou, China was determined by ELISA on serum samples from 206 cats (117 strays and 89 households) and the overall infection rate was 25.24%. The infection rate in stray cats (30.77%) was significantly higher (P < 0.05) than in household cats (17.98%). The rate of infection between male and female cats of both groups was not significantly different (P > or = 0.05), 28.13% versus 32.61% for male and female in stray cats, respectively, and 18% versus 17.95% in household cats. The present investigation demonstrated that the prevalence of T. gondii infection in cats in Guangzhou was high, especially in stray cats, which are probably the main source of T. gondii infection in this area. Integrated control strategies and measures should be implemented to prevent and control T. gondii infection in both stray and household cats, which will have significant implications for the control of human infection with T. gondii.