Attenuation of donor-reactive T cells allows effective control of allograft rejection using regulatory T cell therapy

Regulatory T cells (Tregs) are essential for the establishment and maintenance of immune tolerance, suggesting a potential therapeutic role for Tregs in transplantation. However, Treg administration alone is insufficient in inducing long-term allograft survival in normal hosts, likely due to the high frequency of alloreactive T cells. We hypothesized that a targeted reduction of alloreactive T effector cells would allow a therapeutic window for Treg efficacy. Here we show that preconditioning recipient mice with donor-specific transfusion followed by cyclophosphamide treatment deleted 70-80% donor-reactive T cells, but failed to prolong islet allograft survival. However, infusion of either 5 × 10(6) Tregs with direct donor reactivity or 25 × 10(6) polyclonal Tregs led to indefinite survival of BALB/c islets in more than 70% of preconditioned C57BL/6 recipients. Notably, protection of C3H islets in autoimmune nonobese diabetic mice required islet autoantigen-specific Tregs together with polyclonal Tregs. Treg therapy led to significant reduction of CD8(+) T cells and concomitant increase in endogenous Tregs among graft-infiltrating cells early after transplantation. Together, these results demonstrate that reduction of the donor-reactive T cells will be an important component of Treg-based therapies in transplantation.

Pretreatment of furfural industrial wastewater by Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate processes: a comparative study

The Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate (PDS) processes have been applied for the treatment of actual furfural industrial wastewater in this paper. Through the comparative study of the three processes, a suitable pretreatment technology for actual furfural wastewater treatment was obtained, and the mechanism and dynamics process of this technology is discussed. The experimental results show that Fenton technology has a good and stable effect without adjusting pH of furfural wastewater. At optimal conditions, which were 40 mmol/L H₂O₂ initial concentration and 10 mmol/L Fe²⁺ initial concentration, the chemical oxygen demand (COD) removal rate can reach 81.2% after 90 min reaction at 80 °C temperature. The PDS process also has a good performance. The COD removal rate could attain 80.3% when Na₂S₂O₈ initial concentration was 4.2 mmol/L, Fe²⁺ initial concentration was 0.1 mol/L, the temperature remained at 70 °C, and pH value remained at 2.0. The electro-Fenton process was not competent to deal with the high-temperature furfural industrial wastewater and only 10.2% COD was degraded at 80 °C temperature in the optimal conditions (2.25 mA/cm² current density, 4 mg/L Na₂SO₄, 0.3 m³/h aeration rate). For the Fenton, electro-Fenton and PDS processes in pretreatment of furfural wastewater, their kinetic processes follow the pseudo first order kinetics law. The pretreatment pathways of furfural wastewater degradation are also investigated in this study. The results show that furfural and furan formic acid in furfural wastewater were preferentially degraded by Fenton technology. Furfural can be degraded into low-toxicity or nontoxic compounds by Fenton pretreatment technology, which could make furfural wastewater harmless and even reusable.

Clinical grade manufacturing of human alloantigen-reactive regulatory T cells for use in transplantation

Regulatory T cell (Treg) therapy has the potential to induce transplantation tolerance so that immunosuppression and associated morbidity can be minimized. Alloantigen-reactive Tregs (arTregs) are more effective at preventing graft rejection than polyclonally expanded Tregs (PolyTregs) in murine models. We have developed a manufacturing process to expand human arTregs in short-term cultures using good manufacturing practice-compliant reagents. This process uses CD40L-activated allogeneic B cells to selectively expand arTregs followed by polyclonal restimulation to increase yield. Tregs expanded 100- to 1600-fold were highly alloantigen reactive and expressed the phenotype of stable Tregs. The alloantigen-expanded Tregs had a diverse TCR repertoire. They were more potent than PolyTregs in vitro and more effective at controlling allograft injuries in vivo in a humanized mouse model.

The nature and origin of nucleus-like intracellular inclusions in Paleoproterozoic eukaryote microfossils

The well-known debate on the nature and origin of intracellular inclusions (ICIs) in silicified microfossils from the early Neoproterozoic Bitter Springs Formation has recently been revived by reports of possible fossilized nuclei in phosphatized animal embryo-like fossils from the Ediacaran Doushantuo Formation of South China. The revisitation of this discussion prompted a critical and comprehensive investigation of ICIs in some of the oldest indisputable eukaryote microfossils-the ornamented acritarchs Dictyosphaera delicata and Shuiyousphaeridium macroreticulatum from the Paleoproterozoic Ruyang Group of North China-using a suite of characterization approaches: scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam scanning electron microscopy (FIB-SEM). Although the Ruyang acritarchs must have had nuclei when alive, our data suggest that their ICIs represent neither fossilized nuclei nor taphonomically condensed cytoplasm. We instead propose that these ICIs likely represent biologically contracted and consolidated eukaryotic protoplasts (the combination of the nucleus, surrounding cytoplasm, and plasma membrane). As opposed to degradational contraction of prokaryotic cells within a mucoidal sheath-a model proposed to explain the Bitter Springs ICIs-our model implies that protoplast condensation in the Ruyang acritarchs was an in vivo biologically programmed response to adverse conditions in preparation for encystment. While the discovery of bona fide nuclei in Paleoproterozoic acritarchs would be a substantial landmark in our understanding of eukaryote evolution, the various processes (such as degradational and biological condensation of protoplasts) capable of producing nuclei-mimicking structures require that interpretation of ICIs as fossilized nuclei be based on comprehensive investigations.

Large adipocytes function as antigen-presenting cells to activate CD4(+) T cells via upregulating MHCII in obesity

BACKGROUND/OBJECTIVES

Although obesity is associated with low-grade inflammation and metabolic disorders, clinical studies suggested some obese people were metabolically healthy with smaller adipocyte size compared with metabolically abnormal obese (MAO). This indicated adipocyte size may be an important predictor underlay the distinction between MAO and metabolically healthy obese. As recent study has shown that adipocytes expressed class II major histocompatibility complex (MHCII), which functioned as APCs during obesity. However, the relationship between adipocyte hypertrophy and MHCII expression was not involved. Here we hypothesize that hypertrophic adipocytes could be associated with upregulating MHCII to influence adipose tissue metabolism.

METHODS

Adipocytes were sorted by fluorescence-activated cell sorting (FACS) according to the cell size from MAO mice. The activation of MHCII, T cells and related signaling molecules were examined by FACS, ELISA and western blotting. 3T3-L1 cell line and primary adipocytes were used to examine the effect of free fatty acids (FFA) on adipocytes enlargement and MHCII expression.

RESULTS

MAO mice had a significant increase in adipocytes size and FFA concentration. The large adipocytes from both obese and non-obese mice expressed higher levels of MHCII than small adipocytes. Importantly, large adipocytes from obese mice stimulated CD4(+) T cells to secrete more interferon (IFN)-γ. Furthermore, the activation of the JNK-STAT1 pathway was involved in upregulation of MHCII in large adipocytes. In vitro FFA treatment promoted adipocyte hypertrophy and expression of MHCII-associated genes.

CONCLUSIONS

This study demonstrates that large adipocytes highly express MHCII and function as APC to stimulate IFN-γ-expressing CD4(+) T cells, in which FFA may have important roles before IFN-γ elevated. These findings suggest that adipocyte hypertrophy, rather than overall obesity, is the major contributor to adipose tissue inflammation and insulin resistance.

Changes in and shortcomings of drug stockpiling, vaccine development and related policies during outbreaks of avian influenza A H5N1, H1N1, and H7N9 among humans

The purpose of this paper is to provide a reference for the future stockpiling of drugs and developing vaccines for treatment of emerging infectious diseases by summarizing the status of drug stockpiling, vaccine development, and related policies during three major outbreaks of avian influenza among humans (H5N1 in 2003, H1N1 in 2009, and H7N9 in 2013). Documents regarding drug stockpiling and vaccine development during three influenza outbreaks have been reviewed. Results indicated that the response to pandemic influenza outbreaks has improved markedly in terms of stockpiles of antivirals and vaccine development. These improvements also suggest advances in related policy planning. These trends also foreshadow better prospects for prevention and control of emerging infectious diseases. However, the rationality of drug stockpiling and international cooperation still needs to be enhanced.

Serum level of soluble fibrinogen-like protein 2 in renal allograft recipients with acute rejection: a preliminary study

BACKGROUND

Soluble fibrinogen-like protein 2 (sfgl2), which is mainly secreted by T cells, is a novel effector of regulatory T cells with immunosuppressive functions. The aim of this study was to investigate serum levels of sfgl2 among renal allograft recipients.

METHODS

From November 2010 to August 2011 we retrospectively divided 47 renal allograft recipients into an acute rejection (n = 19) versus a stable group (n = 28) according to allograft biopsy results, using the Banff 2007 classification. The acute rejection group was subdivided into grade I (n = 8) versus grade II T-cell-mediated (n = 6) or antibody-mediated rejection episodes (n = 5). Peripheral blood samples were collected at the time of biopsy. Fourteen healthy volunteers were included as normal group controls. Serum levels of sfgl2 were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Serum levels of sfgl2 were increased among renal allograft recipients suffering from biopsy-proven acute rejection episodes (61.91 ± 45.68 ng/mL), versus those with stable allografts (38.59 ± 19.92 ng/mL, P < .05) or healthy volunteers (29.10 ± 18.08 ng/mL, P < .05). The sfgl2 level was significantly higher among patients with antibody-mediated (118.48 ± 55.54 ng/mL) than T-cell-mediated acute rejection episodes (41.71 ± 16.44 ng/mL, P < .01). Serum sfgl2 levels were remarkably elevated in patients with grade II (51.87 ± 19.13 ng/mL) versus grade I T-cell-mediated rejection (34.10 ± 9.26 ng/mL, P < .05).

CONCLUSIONS

Serum sfgl2 levels were increased among renal allograft recipients with acute rejection episodes to an extent dependent upon the pathological type and severity of the response.

Energetic coupling between an oxidizable cysteine and the phosphorylatable N-terminus of human liver pyruvate kinase

During our efforts to characterize the regulatory properties of human liver pyruvate kinase (L-PYK), we have noted that the affinity of the protein for phosphoenolpyruvate (PEP) becomes reduced several days after cell lysis. A 1.8 Å crystallographic structure of L-PYK with the S12D mimic of phosphorylation indicates that Cys436 is oxidized, the first potential insight into explaining the effect of "aging". Interestingly, the oxidation is only to sulfenic acid despite the crystal growth time period of 2 weeks. Mutagenesis confirms that the side chain of residue 436 is energetically coupled to PEP binding. Mass spectrometry confirms that the oxidation is present in solution and is not an artifact caused by X-ray exposure. Exposure of the L-PYK mutations to H₂O₂ also confirms that PEP affinity is sensitive to the nature of the side chain at position 436. A 1.95 Å structure of the C436M mutant of L-PYK, the only mutation at position 436 that has been shown to strengthen PEP affinity, revealed that the methionine substitution results in the ordering of several N-terminal residues that have not been ordered in previous structures. This result allowed speculation that oxidation of Cys436 and phosphorylation of the N-terminus at Ser12 may function through a similar mechanism, namely the interruption of an activating interaction between the nonphosphorylated N-terminus with the nonoxidized main body of the protein. Mutant cycles were used to provide evidence that mutations of Cys436 are energetically synergistic with N-terminal modifications, a result that is consistent with phosphorylation of the N-terminus and oxidation of Cys436 functioning through mechanisms with common features. Alanine-scanning mutagenesis was used to confirm that the newly ordered N-terminal residues were important to the regulation of enzyme function by the N-terminus of the enzyme (i.e., not an artifact caused by the introduced methionine substitution) and to further define which residues in the N-terminus are energetically coupled to PEP affinity. Collectively, these studies indicate energetic coupling (and potentially mechanistic similarities) between the oxidation of Cys436 and phosphorylation of Ser12 in the N-terminus of L-PYK.

High-resolution capillary isoelectric focusing-electrospray ionization mass spectrometry for hemoglobin variants analysis

On-line capillary isoelectric focusing (CIEF)-electrospray ionization mass spectrometry (ESIMS) as a two-dimensional separation system is employed for high-resolution analysis of hemoglobin variants A, C, S, and F. The effects of moving ionic boundary inside the CIEF capillary and MS scan rate on the separation resolution and mass detection of hemoglobin variants are investigated. The formation of a moving ionic boundary due to the replacement of background electrolyte counterions with sheath liquid counterions can be minimized by combining cathodic mobilization with a gravity-induced hydrodynamic flow. Hemoglobin variants F and A, with a pI difference of 0.05 pH unit, are almost baseline resolved and identified in CIEF-ESIMS. The concentration detection limit for each hemoglobin variant is in the range of 10(-)(8) M, comparable to that obtained in two-dimensional gel electrophoresis using silver staining. Initial preconcentration during the focusing step and the use of single-ion monitoring scan mode are responsible for improving detection limits.

Decreased risk of graft failure with maternal liver transplantation in patients with biliary atresia

The presence of maternal cells in offspring may promote tolerance to noninherited maternal antigens (NIMAs). Children with biliary atresia (BA) have increased maternal cells in their livers, which may impact tolerance. We hypothesized that patients with BA would have improved outcomes when receiving a maternal liver. We reviewed all pediatric liver transplants recorded in the SRTR database from 1996 to 2010 and compared BA and non-BA recipients of maternal livers with recipients of paternal livers for the incidences of graft failure and retransplantation. Rejection episodes after parental liver transplantation were examined for patients transplanted at our institution. BA patients receiving a maternal graft had lower rates of graft failure compared to those receiving a paternal graft (3.7% vs. 10.5%, p = 0.02) and, consequently, fewer episodes of retransplantation (2.7% vs. 7.5%, p = 0.04). These differences were not seen among non-BA patients or among BA patients who received female deceased donor grafts. In patients transplanted at our institution, paternal liver transplantation was associated with an increased incidence of refractory rejection compared to maternal liver transplantation only in BA. Our data support the concept that maternal cells in BA recipients promote tolerance to NIMAs and may be important in counseling BA patients who require liver transplantation.

Allosteric regulation of human liver pyruvate kinase by peptides that mimic the phosphorylated/dephosphorylated N-terminus

An advantage of studying allosteric regulation over covalent modification is that allostery allows the experimentalist to vary the concentration of effector, thereby allowing independent quantification of effector binding and allosteric coupling. In turn, this capacity allows the use of effector analogues to determine which regions of the effector contribute to effector binding and which contribute to allosteric regulation. Like many other proteins, human liver pyruvate kinase (hL-PYK) is regulated by phosphorylation. The phosphorylation of hL-PYK occurs on Ser12 of the N-terminus. Phosphorylation appears to interrupt an interaction (distant from the active site) between the N-terminus and the main body of the protein. Since this interaction increases the affinity of hL-PYK for the substrate (phosphoenolpyruvate, PEP), phosphorylation-dependent interruption of the N-terminus/main-body interaction results in an antagonism of PEP binding. Due to the advantages of studying an allosteric system, we detail a protocol to express and purify N-terminal peptides of hL-PYK using a SUMO-fusion system. We further demonstrate that these peptides act as allosteric regulators that modulate the affinity of hL-PYK for PEP.

Production of Y‐Ba‐Cu‐0 Superconducting Thin Films by an Aerosol Chemical Vapor Deposition Process

Thin film production by aerosol deposition is a simple, non‐vacuum method, which under certain conditions of the process parameters, can be considered as a chemical vapor deposition (CVD) process. In this paper we describe the formation of superconducting thin films by aerosol deposition in the CVD regime by using metal‐organic precursors. The best results were obtained with the metal β‐diketonates of Y, Ba and Cu dissolved in butylacetate. This solution was nebulized and sprayed on a heated Si‐substrate with a Zr02‐buffer layer at a temperature of 450 C. After deposition a final heat treatment at a temperature of 800 C was applied. The resulting superconducting film has a Tc>2ero of 75 K.

The feasibility of using magnetic nanoparticles modified as gene vector

OBJECTIVE

To evaluate the feasibility of using magnetic nanoparticles (MNPs) as gene vector and the effect of magnetic field on efficiency of transfection.

METHODS

Magnetic nanoparticles were prepared by controlling some chemical reaction parameters through a partially reduction precipitation method with ferric chloride aqueous solution as precursor material. The surface of particles was modified by polyethyleneimine (PEI) agents. The appearance, the size distribution, structure and phase constitute of MNPs were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD); the potential of absorbing DNA of MNPs was analysed by electrophoresis. Transfection was determined by delivering reporter gene, PGL2-control encoding luciferase, to different cell lines using MNPs-PLL as vector. The effect of magnetic field on the efficiency of transfection was determined using Nd-Fe-B permanent magnet.

RESULTS

Foreign gene could be delivered to various cell lines by MNPs-PLL and expressed with high efficiency but the transfection efficiency and time course varied in the different cell lines studied. Magnetic field could enhance the efficiency of transfection by 5-10 fold.

CONCLUSION

MNPs- PLL can be used as a novel non-viral gene vector in vitro, which offers a basis for gene delivery in vivo.

Isolation and characterization of a sea cucumber fucoidan-utilizing marine bacterium

AIMS

To isolate a fucoidan-utilizing strain from seawater for sea cucumber fucoidan degradation.

METHODS AND RESULTS

The utilization of sea cucumber fucoidan was monitored by H(2)SO(4)-phenol assay for neutral sugar. The bacterium CZ1127 was isolated from seawater and shown to have a relatively large maximum fucoidan-utilizing rate of 81.5%. CZ1127 was confirmed to belong to the family Flavobacteriaceae by 16S rDNA and physiological analyses. This strain has an ability to utilize fucoidans extracted from various sea cucumbers to different degrees. Both extracellular and intracellular enzymes of CZ1127 could degrade sea cucumber fucoidan, as confirmed by high-performance size exclusion chromatography. The M(r) of sea cucumber fucoidan could be reduced from 792.6 kDa to at least 3.7 kDa by the crude intracellular enzyme of this strain.

CONCLUSIONS

The marine bacterial strain CZ1127, which belongs to the family Flavobacteriaceae, was found to utilize various sea cucumber fucoidans and furthermore showed promise in sea cucumber fucoidan enzymatic degradation and oligosaccharide preparation.

SIGNIFICANCE AND IMPACT OF THE STUDY

The finding of a novel source can be applied in sea cucumber fucoidan enzymatic degradation. Furthermore, it is the first definite report of a bacterial strain that can utilize the fucoidans from various sea cucumbers.

Partial cancerous changes eventually developing into superficial spreading cancer over 18 months

In this report, we describe a patient presenting with the superficial spreading type of early gastric cancer (egc) accompanied by cancerous ulcers. Disease progression and treatment outcome are discussed. After symptoms persisted for more than 1 year, the patient underwent total gastrectomy with D2 lymph node dissection. The patient was diagnosed with superficial spreading cancer (ssc), accompanied by an extensive iic lesions. The progression of this patient suggests that the co-occurrence of cancerous ulcers may contribute to egc development to some extent. As is known, egc often develops into advanced gastric cancer with time. However, in our case, we observed a process during which partial cancerous changes developed into ssc over 18 months. Superficial spreading cancer should be considered an egc variant, which may have the ability to spread superficially along the stomach wall without invading the muscularis propria. But we speculate that, if gene expression changes for some reason, the malignant ssc cells may acquire the ability to grow deeply into the stomach wall. Eventually, Borrmann type iv gastric cancer may develop.

Structural studies of the N-terminus of Connexin 32 using 1H NMR spectroscopy

The amino terminus of gap junction proteins, connexins, plays a fundamental role in voltage gating and ion permeation. We have previously shown with (1)H NMR that the structure of the N-terminus of a representative connexin molecule contains a flexible turn around glycine 12 [P.E. Purnick, D.C. Benjamin, V.K. Verselis, T.A. Bargiello, T.L. Dowd, Arch. Biochem. Biophys. 381 (2000) 181-190] allowing the N-terminus to reside at the cytoplasmic entry of the channel forming a voltage-sensor. Previous functional studies or neuropathies have shown that the mutation G12Y and G12S form non-functional channels while functional channels are formed from G12P. Using 2D (1)H NMR we show that similar to G12, the structure of the G12P mutant contains a more flexible turn around residue 12, whereas the G12S and G12Y mutants contain tighter, helical turns in this region. These results suggest an unconstrained turn is required around residue 12 to position the N-terminus within the pore allowing the formation of the cytoplasmic channel vestibule, which appears to be critical for proper channel function.

Identification of tumor stem-like cells in a mouse myeloma cell line

We used colony formation assay in the soft agar media or the serum-free media, the methods of identifying BrdU-label-retaining cells and the SP cells as well as the tumorigenicity test in BALB/c mice, respectively, to analyze tumor stem like cells in the SP2/0 cell line. The results showed that a few SP2/0 cells were capable of forming colonies in the soft agar media, contained BrdU-label-immortal strand in the SP2/0 cell line. The SP2/0 cells in the serum-free media gained higher tumorigenicity in the BALB/c mice than the SP2/0 cells cultivated in the complete media did. Overall, only a few of the SP2/0 cells were found to possess the characteristics of tumor stem-like cells, such as high proliferative potency, more self-renewal and stronger tumorigenesis, or greater similarity to the tumor stem cells (TSCs) traits. The biology of tumor stem-like cells contributes to the identification of molecular targets important for future tumor therapy.

An activating interaction between the unphosphorylated n-terminus of human liver pyruvate kinase and the main body of the protein is interrupted by phosphorylation

The initial 26 amino acids of human liver pyruvate kinase (L-PYK) are not present/observed in the crystal structure. This region includes Ser12, the site of hormone-dependent phosphorylation. Truncating the N-terminus of L-PYK mimics the effects of phosphorylation by causing a decrease in apparent phosphoenolpyruvate (PEP) affinity. An N-terminus truncation series was used to map the minimum number of residues that could be removed to result in the decrease in apparent PEP affinity. Results are consistent with a mechanism by which phosphorylation at Ser12 interrupts an activating interaction of N-terminal residues (including those at positions 7-10) with the main body of the protein, as a means of inhibiting substrate affinity.

Preferential priming of alloreactive T cells with indirect reactivity

The relative contributions of the direct and indirect pathways in alloimmune responses have not been fully elucidated. We report a novel murine TCR transgenic system that can simultaneously track the CD4-direct (CD4-d), CD4-indirect (CD4-i) and CD8-direct (CD8-d) pathways after transplantation. Using this system, we have observed a profoundly greater proliferation of CD4-i T cells relative to CD4-d and CD8-d T cells after transplantation. Furthermore, a much larger proportion of CD4-i T cells attain an effector phenotype. We also analyzed endogenous, wild-type T cells using enzyme-linked immunospot analysis. In naïve mice, T cells with indirect reactivity were undetectable, but T cells with direct reactivity were abundant. However, 10 days after skin or heterotopic heart transplantation, CD4-i T cells comprised approximately 10% of the CD4+ response. Consistent with increased priming of the CD4-i pathway, we observed that the CD4-i T cells were further enriched in the effector cells migrating to the allograft and in memory-like T cells persisting after rejection. Thus, priming of the CD4-i pathway is favored after transplantation, allowing a rare population to rapidly become a major component of the CD4+ T-cell response in acute allograft rejection. The generalizability of this observation to other models remains to be determined.

Apoptosis inducing and differentiation enhancement effect of oridonin on the all-trans-retinoic acid-sensitive and -resistant acute promyelocytic leukemia cells

We investigated the effects of oridonin (Ori), a diterpenoid isolated from Rabdosia rubescens, on apoptosis and differentiation of all-trans-retinoic acid (ATRA)-sensitive (NB4) and ATRA-resistant (NB4-R1) cells. The results showed that reactive oxygen species initiates Ori-induced apoptosis. In addition, we found that neither Ori nor ATRA (10 nM) alone induced marked cell differentiation, while co-treatment of these two compounds can induce differentiation of NB4 and NB4-R1 cells which was accompanied by increased RARalpha, C/EBPepsilon or C/EBPbeta. This is the first report to show that RARalpha could be accumulated by Ori which may be useful as a probe to investigate the mechanism of RARalpha catabolism. These results suggest that Ori is a potential candidate for acute promyelocytic leukemia cancer therapy.

The 5-HT2 antagonist ketanserin is an open channel blocker of human cardiac ether-à-go-go-related gene (hERG) potassium channels

BACKGROUND AND PURPOSE

Ketanserin, a selective 5-HT receptor antagonist, prolongs the QT interval of ECG in patients. The purpose of the present study was to determine whether ketanserin would block human cardiac ether-à-go-go-related gene (hERG) potassium channels.

EXPERIMENTAL APPROACH

Whole-cell patch voltage-clamp technique was used to record membrane currents in HEK 293 cells expressing wild type or mutant hERG channel genes.

KEY RESULTS

Ketanserin blocked hERG current (I(hERG)) in a concentration-dependent manner (IC50=0.11 microM). The drug showed an open channel blocking property, the block increasing significantly at depolarizing voltages between +10 to +60 mV. Voltage-dependence for inactivation of hERG channels was negatively shifted by 0.3 microM ketanserin. A 2.8 fold attenuation of inhibition by elevation of external K+ concentration (from 5.0 to 20 mM) was observed, whereas the inactivation-deficient mutants S620T and S631A had the IC50s of 0.84 +/- 0.2 and 1.7 +/-0.4 microM (7.6 and 15.4 fold attenuation of block). In addition, the hERG mutants in pore helix and S6 also significantly reduced the channel block (2-59 fold) by ketanserin.

CONCLUSIONS AND IMPLICATIONS

These results suggest that ketanserin binds to and blocks the open hERG channels in the pore helix and the S6 domain; channel inactivation is also involved in the blockade of hERG channels. Blockade of hERG channels most likely contributes to the prolongation of QT intervals in ECG observed clinically at therapeutic concentrations of ketanserin.

Long-term cognitive functions in neonatal short bowel syndrome patients

OBJECTIVE

The aim of the study was to evaluate the long-term effects of neonatal short bowel syndrome on cognitive functions during development.

SUBJECTS AND METHODS

Nine patients diagnosed with short bowel syndrome during the neonatal period were enrolled in this study. Their medical records were reviewed; anthropometric measurements and blood tests were assayed; IQ tests (the Chinese versions of WAIS-R, WPPSI-R and WISC-R) were performed depending on their age, and a BSID assessment was carried out in those patients less than 4 years old.

RESULTS

Eight of 9 patients were followed up except for one patient who died in a car accident at the age of three. All patients had been weaned off parenteral nutrition for more than 2 years. The average residual small bowel length was 58.1 cm (range 35-70 cm), and the mean parenteral nutrition (PN) duration was 73.1 days (43-147 days). The mean duration of the period without PN was 7.4 years (range 2.1-17.1 years). Weight, height and BMI for age were normal in 7 children except for 1 child, who was overweight. Hemoglobin and albumin concentrations were normal in all 8 patients. Evaluation of cognitive development showed normal results for all 8 patients while a verbal/performance discrepancy was found in 2.

CONCLUSION

Patients with neonatal SBS who were weaned off PN for more than 2 years were found to have normal growth and cognitive development during this long-term follow-up. There was no evidence for a strong correlation between SBS and nutritional/cognition disorder. Longer term and controlled studies with a larger sample size are warranted.

Mathematical analysis of an integral equation arising from population dynamics

In this paper, we establish the existence of travelling wave solution to an intrinsically non-linear differential-integral equation formed as a result of mathematical modelling of the evolution of an asexual population in a changing environment. This equation is first converted to a non-linear integral equation. The discretization and manipulation of the corresponding eigenvalue problem allows us to use the theory of positive matrices to get some very useful estimates and then to confirm the existence of solution. We also exhibit numerical simulation results and explain the biological meaning of the results.

β-CTX and ICTP Act as Indicators of Skeletal Metastasis Status in Male Patients with Non-Small Cell Lung Cancer

Bone metastasis is common in lung cancer patients and associated with reduced quality of life and reduced overall and median survival, so the early detection of bone metastasis and monitoring of its status is very important for clinicians. Serum bone-specific alkaline phosphatase (BAP), osteocalcin (OC), β isomer of C-terminal telopeptide of type I collagen (β-CTX) and cross-linked C-terminal telopeptide of type I collagen (ICTP) were compared with regard to their usefulness as indicators of bone metastasis in lung cancer. The serum concentrations of the 4 markers were measured by commercially available tests in 96 male patients with non-small cell lung cancer and 30 male patients with other pulmonary diseases. The levels of both β-CTX and ICTP were significantly higher in 61 lung cancer patients with bone metastases than in 35 lung cancer patients without bone metastases (both p<0.001), and significantly correlated with the extent of bone disease. Although ICTP had a better sensitivity and accuracy than β-CTX (75.4% vs 65.6% and 72.9% vs 68.8%, respectively), they had a similar area under the receiver operating characteristic curve (0.85 vs 0.83). These results support the use of β-CTX and ICTP as an adjunct tool for the diagnosis and screening of bone metastasis in lung cancer.

CD4+CD25+ regulatory T cells in transplantation: progress, challenges and prospects

The involvement of CD4(+)CD25(+) regulatory T cells (Treg) in general immune homeostasis and protection from autoimmune syndromes is now well established. Similarly, there has been increasing evidence for Treg involvement in allograft rejection and current immunotherapies. However, despite significant advances in understanding the development, function, and therapeutic efficacy of Treg in certain well-defined rodent models, the relevance of Treg to clinical transplantation remains unclear. In this review, we summarize our current understanding of the role of Treg in immunity and organ transplantation in experimental and clinical settings. In addition, we review advances in using Treg as a form of immune therapy. The goal is to highlight the complexities and opportunities in the field and to provide evidence to support the use of antigen-specific Tregs in the context of transplantation to facilitate a robust and selective state of immune tolerance.

Identification of B cell epitopes at the C-terminus of latency-associated nuclear protein of the kaposi's sarcoma-associated herpesvirus

The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) plays a key role in the induction of cell transformation, maintenance of viral episome, and modulation of immune response in human. To identify the presence of B cell epitopes within C-terminus of LANA and to characterize the monoclonal antibodies (MAbs) against this protein, we expressed the C-terminal region at aa 794-1000 of LANA (pLANA-C) in Escherichia coli as a fusion protein. KSHV-positive human sera were able to recognize the recombinant LANA-C in the Western blot analysis and ELISA. Mapping of antigenic epitopes of pLANA-C by KSHV-positive human sera revealed two B cell antigenic epitopes located at aa 846-854 and aa 794-822. The MAb 3F11 recognized a region between at aa 840 to 846 of LANA and exhibited a strong and specific binding to both pLANA-C and native viral LANA. These findings showed that pLANA-C and MAb 3F11 could be used for the detection of KSHV antibodies in human sera and for the advanced study of biological functions of LANA.

The effect of renal ischemia-reperfusion injury on expression of RAE-1 and H60 in mice kidney

INTRODUCTION

NKG2D, an activating receptor, may trigger NK and CD8+ T cells. Ligands for NKG2D and major histocompability complex class I chain-related antigen (MIC) have been reported to be expressed in rejected human renal allografts. MIC-NKG2D engagement may induce natural killer (NK) cell activation providing T-cell costimulation. We hypothesized that this interaction between innate and adaptive immunity may occur during kidney ischemia-reperfusion injury (IRI).

METHODS

Male C57BL/6 mice after right renal resection were subjected to 35 minutes of left renal ischemia: the ischemic group. Sham-operated mice underwent the same protocol without vascular occlusion. The sham and ischemic kidneys were removed at 2 to 7, 10, 14, or 28 days postoperatively. The normal, sham, and ischemic kidney tissues were collected for reverse-transcriptase polymerase chain reaction, and immunohistochemistry analysis of MIC homologues in mice (Rae-1 and H60).

RESULTS

Compared with no expression in sham control and normal kidneys, IRI caused mRNA expression of Rae-1 from 2 to 10 days postoperatively and protein expression of Rae-1 from 2 to 14 days postoperatively in ischemic kidneys. We observed no expression of H60 mRNA or protein in any kidney.

CONCLUSION

H60 transcripts have been reported to be present in the BALB/c background but not in C57BL/6. We found IRI did not cause H60 mRNA on protein expression in C57BL/6 kidneys. Rae-1 was absent in normal C57BL/6 kidneys. The IRI-induced expression of the NKG2D ligand, Rae-1, might activate NK and CD8+ T cells. Our results suggested that MIC may be an important link between innate and adaptive immunity in kidney IRI.

[Preparation and characterization of the monoclonal antibodies against Japanese encephalitis virus.]

BACKGROUND

To prepare mouse monoclonal antibodies (McAbs) against Japanese encephalitis virus (JEV)and evaluate their biological characteristics.

METHODS

McAbs against JEV were prepared by immunizing, fusing, cloning and screening. Their sensitivity, specificity, universality and neutralizing function were analyzed with ELISA, IFA, NT and Western blot.

RESULTS

Titers of three McAbs against JEV were higher than 106. Three McAbs only reacted with JEV and not with other nine arboviruses. F12.37 could react with ten strains of JEV and sensitively detected ten replicating strains of viruses in BHK cell. The strains P3 and SH03-103 of JEV were neutralized by F12.37, its titers of protecting 50% cell were 3.2x105 and 105. Western blot showed that F12.37 reacted with envelop(E)protein of JEV.

CONCLUSION

Three McAbs against JEV had high titer and good specificity. And F12.37 was very sensitive and universal in reacting with JEV, and neutralized JEV of Genotype I and Genotype .The binding site of F12.37 lays in E protein of JEV.

Study on energy metabolism in perioperative infants

OBJECTIVES

To evaluate resting energy expenditure (REE) in surgical infants and define the effects of the degree of stress on its level.

SUBJECTS AND METHODS

Between June 1999 and June 2003 forty-five infants awaiting surgery (boys/girls: 32/13) from the Department of Pediatric Surgery were entered in the study. Indirect calorimetry was used to measure the REE of all the patients before operation and 1 - 7 days after operation. Clinical data were collected, including age, weight, height, diagnosis, operative method, site and duration, and first day postoperative C-reactive protein (CRP) levels.

RESULTS

The REE before operation did not differ significantly from the postoperative values (paired t-test, p > 0.05). The predicted REE was significantly higher than the measured REE even before and after the operation (p < 0.01). REE values in the first three postoperative days were lower in the mild stress group than in the severe surgical stress group.

CONCLUSIONS

REE variation among the patients is relatively large. Changes in REE may be related to the degree of stress. Predicted REE values may be not a good reflection of measured REE.

Elimination of metformin-croscarmellose sodium interaction by competition

During analytical method development and validation, a strong charge interaction between metformin and croscarmellose sodium was observed when the aqueous solution containing metformin was spiked with croscarmellose sodium. The charge interaction resulted in the retention of metformin in croscarmellose sodium and caused a serious drug recovery problem. The percent recovery of metformin in the solution was much lower than its theoretical values, especially in the low metformin concentration range. To overcome the metformin-croscarmellose interaction, arginine was selected as a competitor for the binding sites on croscarmellose sodium. Because of the competition and stronger interaction between arginine and croscarmellose sodium than metformin and croscarmellose sodium, a complete recovery of metformin in presence of arginine in both low and high concentration ranges was achieved. The effect of arginine on the recovery of metformin and the competition mechanism are discussed in this paper.