Origin of the spin density wave instability in AFe2As2 (A=Ba,Sr) as revealed by optical spectroscopy

We performed optical spectroscopy measurement on single crystals of BaFe2As2 and SrFe2As2, the parent compounds of FeAs-based superconductors. Both are found to be quite metallic with fairly large plasma frequencies at high temperature. Upon entering the spin-density-wave state, the formation of partial energy gaps was clearly observed with the surprising presence of two different energy scales. A large part of the Drude component was removed by the gapping of Fermi surfaces. Meanwhile, the carrier scattering rate was even more dramatically reduced. We elaborate that the spin-density-wave instability is more likely to be driven by the Fermi surface nesting of itinerant electrons than a local-exchange mechanism.

Nanoparticle delivery of anti-metastatic NM23-H1 gene improves chemotherapy in a mouse tumor model

Gene therapy provides a promising approach for cancer treatment. Earlier studies suggested that poly-L-lysine-modified iron oxide nanoparticles (IONP-PLL) might be a promising gene delivery system that can transfect DNA efficiently in vitro and in vivo. In this study we used IONP-PLL as gene carriers to deliver the NM23-H1 gene, the first suppressor gene of cancer metastasis, to tumor cells in vivo. The intravenous injection of IONP-PLL carrying NM23-H1-GFP plasmid DNA significantly extended the survival time of an experimental pulmonary metastasis mouse model. In the IONP-PLL/NM23-H1-GFP-treated group, metastasis was clearly suppressed compared with the group treated with free NM23-H1-GFP plasmid. Furthermore, this gene therapy combined with cyclophosphamide treatment resulted in longer survival times and greater suppression of metastasis growth. In conclusion, treatment with IONP-PLL nanoparticles incorporating the NM23-H1gene is an efficient gene therapy method, and it is even more effective in combination with chemotherapy. This approach appears to be a promising strategy for treatment of metastatic tumors.

Origin of the spin density wave instability in AFe2As2 (A=Ba,Sr) as revealed by optical spectroscopy

We performed optical spectroscopy measurement on single crystals of BaFe2As2 and SrFe2As2, the parent compounds of FeAs-based superconductors. Both are found to be quite metallic with fairly large plasma frequencies at high temperature. Upon entering the spin-density-wave state, the formation of partial energy gaps was clearly observed with the surprising presence of two different energy scales. A large part of the Drude component was removed by the gapping of Fermi surfaces. Meanwhile, the carrier scattering rate was even more dramatically reduced. We elaborate that the spin-density-wave instability is more likely to be driven by the Fermi surface nesting of itinerant electrons than a local-exchange mechanism.

Training-induced vascular adaptations to ischemic muscle

Peripheral arterial insufficiency is a progressive degenerative disease associated with an increased morbidity and mortality. It decreases exercise tolerance and often presents with symptoms of intermittent claudication. Enhanced physical activity is one of the most effective means of improving the life of affected patients. While this occurs for a variety of reasons, vascular remodeling can be an important means for improved oxygen exchange and blood flow delivery. Relevant exercise-induced signals stimulate angiogenesis, within the active muscle (e.g. hypoxia), and arteriogenesis (enlargement of pre-existing vessels via increased shear stress) to increase oxygen exchange and blood flow capacity, respectively. Evidence from pre-clinical studies shows that the increase in collateral blood flow observed with exercise progresses over time of training, is accompanied by significant enlargement of isolated collateral vessels, and enhances the responses observed with angiogenic growth factors (e.g. VEGF, FGF-2). Thus, enhanced physical activity can be an effective means of enlarging the structure and function of the collateral circuit. Interestingly, disrupting normal NO production (via L-NAME) eliminates this increase in collateral blood flow induced by training, but does not disturb the increase in muscle capillarity within the active muscle. Similarly, inhibiting VEGF receptor kinase activity eliminates the increase in collateral-dependent blood flow, and lessens, but does not eliminate, angiogenesis within the calf muscle. These findings illustrate distinctions between the processes influencing angiogenesis and arteriogenesis. Further, sympathetic modulation of the collateral circuit does not eliminate the increase in collateral circuit conductance induced by exercise training. These findings indicate that structural enlargement of the collateral vessels is essential to realize the increase in collateral-dependent blood flow capacity caused by exercise training. This raises the potential that meaningful vascular remodeling can occur in patients with intermittent claudication who actively participate in exercise training.

CD8+ T-Cell depletion and rapamycin synergize with combined coreceptor/stimulation blockade to induce robust limb allograft tolerance in mice

The growing development of composite tissue allografts (CTA) highlights the need for tolerance induction protocols. Herein, we developed a mouse model of heterotopic limb allograft in a stringent strain combination in which potentially tolerogenic strategies were tested taking advantage of donor stem cells in the grafted limb. BALB/c allografts were transplanted into C57BL/6 mice treated with anti-CD154 mAb, nondepleting anti-CD4 combined to either depleting or nondepleting anti-CD8 mAbs. Some groups received additional rapamycin. Both depleting and nondepleting mAb combinations without rapamycin only delayed limb allograft rejection, whereas the addition of rapamycin induced long-term allograft survival in both combinations. Nevertheless, robust donor-specific tolerance, defined by the acceptance of a fresh donor-type skin allograft and simultaneous rejection of third-party grafts, required initial CD8(+) T-cell depletion. Mixed donor-recipient chimerism was observed in lymphoid organs and recipient bone marrow of tolerant but not rejecting animals. Tolerance specificity was confirmed by the inability to produce IL-2, IFN-gamma and TNF-alpha in MLC with donor antigen while significant alloreactivity persisted against third- party alloantigens. Collectively, these results show that robust CTA tolerance and mixed donor-recipient chimerism can be achieved in response to the synergizing combination of rapamycin, transient CD8(+) T-cell depletion and costimulation/coreceptor blockade.

Structural and magnetic phase diagram of CeFeAsO(1- x)F(x) and its relation to high-temperature superconductivity

Recently, high-transition-temperature (high-Tc) superconductivity was discovered in the iron pnictide RFeAsO(1-x)F(x) (R, rare-earth metal) family of materials. We use neutron scattering to study the structural and magnetic phase transitions in CeFeAsO(1-x)F(x) as the system is tuned from a semimetal to a high-Tc superconductor through fluorine (F) doping, x. In the undoped state, CeFeAsO develops a structural lattice distortion followed by a collinear antiferromagnetic order with decreasing temperature. With increasing fluorine doping, the structural phase transition decreases gradually and vanishes within the superconductivity dome near x=0.10, whereas the antiferromagnetic order is suppressed before the appearance of superconductivity for x>0.06, resulting in an electronic phase diagram remarkably similar to that of the high-Tc copper oxides. Comparison of the structural evolution of CeFeAsO(1-x)F(x) with other Fe-based superconductors suggests that the structural perfection of the Fe-As tetrahedron is important for the high-Tc superconductivity in these Fe pnictides.

Molecular cloning and expression characterization of ApoC-I in the orange-spotted grouper

Endogenous yolk nutrients are crucial for embryo and larval development in fish, but developmental behavior of the genes that control yolk utilization remains unknown. Apolipoproteins have been shown to play important roles in lipid transport and uptake through the circulation system. In this study, EcApoC-I, the first cloned ApoC-I in teleosts, has been screened from pituitary cDNA library of female orange-spotted grouper (Epinephelus coioides), and the deduced amino acid sequence shows 43.5% identity to one zebrafish (Danio rerio) hypothetical protein similar to ApoC-I, and 21.2%, 21.7%, 22.5%, 20%, and 22.5% identities to Apo C-I of human (Homo sapiens), house mouse (Mus musculus), common tree shrew (Tupaia glis), dog (Canis lupus familiaris) and hamadryas baboon (Papio hamadryas), respectively. Although the sequence identity is low, amphipathic alpha-helices with the potential to bind to lipid were predicted to exist in the EcApoC-I. RT-PCR analysis revealed that it was first transcribed in gastrula embryos and maintained a relatively stable expression level during the following embryogenesis. During embryonic and early larval development, a very high level of EcApoC-I expression was in the yolk syncytial layer, indicating that it plays a significant role in yolk degradation and transfers nutrition to the embryo and early larva. By the day 7 after hatching, EcApoC-I transcripts were observed in brain. In adult, EcApoC-I mRNA was detected abundantly in brain and gonad. In transitional gonads, the EcApoC-I expression is restricted to the germ cells. The data suggested that EcApoC-I might play an important role in brain and gonad morphogenesis and growth.

Absence of donor-derived zona pellucida protein C homolog in the inner perivitelline layer of Peking duck (Anas platyrhynchos)-Japanese quail (Coturnix coturnix japonica) chimeras (Duails)

Avian blastodermal cells at stage X are used to produce interspecies chimeras for heterogenous poultry reproduction. However, recipient-derived inner perivitelline layer (IPVL)-enclosed donor-derived ova may affect the efficiency of germline transmission via chimera. Among the proteins in the IPVL, zona pellucida protein C (ZPC) plays an important role in sperm-egg binding and inducing the acrosome reaction. In the present study, Peking duck blastodermal cells at stage X were transferred into subgerminal cavities of Japanese quail embryos at the same stage. Fourteen female duck-quail chimeras (duails) were hatched and raised to sexual maturity. After being screened by PCR, 3 duails were selected for examination of donor-derived ZPC. A total of 152 IPVL protein samples from the individual eggs laid by the 3 duails then underwent a preliminary examination for the presence of donor-derived ZPC by means of SDS-PAGE, periodic acid-Schiff staining, and Western blotting. A novel 35-kDa ZPC, not observed in quail but in duck, was found in the IPVL of the duails. Further analysis of peptide mass fingerprinting of Peking duck ZPC, Japanese quail ZPC, and the 35-kDa duail ZPC by matrix-assisted laser desorption-ionization reflectron time-of-flight mass spectrometry revealed that the novel ZPC was an isoform of quail ZPC. Moreover, comparison of N-terminal amino acid sequences of these 3 ZPC confirmed that the 35-kDa quail ZPC had more amino acids at the N terminus than did native quail ZPC, and none of the donor-derived ZPC was found in the duails. These findings suggest that it would be difficult to obtain donor-derived offspring by natural mating of interspecies chimeras.

Brain death affects the hepatic immunogenicity of pigs

OBJECTIVE

The purpose of this study was to observe how the brain-death state affects the hepatic immunogenicity of pigs.

MATERIALS AND METHODS

Twelve healthy ChangBai pigs were allocated randomly to 2 groups: control group (n = 6) with Foley catheter balloon placed intracalvarium for 24 hours only versus brain-death group (n = 6) with brain death for 24 hours. The serum and hepatic tissues were obtained at 6, 12, and 24 hours after the initial confirmation of brain death. Tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 were determined by enzyme-linked immunosorbent assay (ELISA). The major histocompatibility complex class II (MHC-II) was determined by immunohistochemistry, and the intercellular adhesion molecule-1 (ICAM-1) mRNA and monocyte chemotactic protein-1 (MCP-1) mRNA by real-time polymerase chain reaction (PCR).

RESULTS

The serum TNF-alpha and IL-6, MHC-II, ICAM-1 mRNA, and MCP-1 mRNA in hepatic tissues in the brain-death group were higher than in the control group; they all increased with time.

CONCLUSION

Brain death increased liver immunogenicity, which may increase the immune lesion and rejection after transplantation.

Cellular distribution of tumour suppressor protein p53 and high-risk human papillomavirus (HPV)-18 E6 fusion protein in wild-type p53 cell lines

Human papillomaviruses (HPVs) are very important pathogens that can be classified as high- and low-risk types based on the lesions they cause. Mucosal high-risk HPV E6 can target and degrade the tumour suppressor p53, hence it is recognized as the major cause of cervical cancer, however, due to a lack of reliable anti-E6 antibodies, the distribution of high-risk HPV E6 protein remains elusive. The present study, therefore, used a mammalian green fluorescent protein (GFP) expression system to express GFP-18 E6 fusion proteins in wild-type p53 cells, SMMC-7721 and HCT116, in order to trace the location and expression of HPV E6 and p53 protein. Following transfection, expression of GFP-18 E6 was found to be located in the nucleus, and endogenous wild-type p53 was also located there with GFP-18 E6.

HLA-A*3318, a novel allele, identified by sequence-based typing in a Chinese individual

We report a novel human leucocyte antigen (HLA)-A allele, officially named as A*3318, which was found during high-resolution sequence-based typing in a Chinese potential hematopoietic stem cell transplantation donor. Compared with the HLA-A*330301 sequence, the A*3318 has one nucleotide substitution in exon 3: at nt 413 where A-->G resulting in an amino acid substitution from Q (CAG) to R (CGG) at codon 114.

Using multidimensional patterns of amino acid attributes for QSAR analysis of peptides

On the basis of exploratory factor analysis, six multidimensional patterns of 516 amino acid attributes, namely, factor analysis scales of generalized amino acid information (FASGAI) involving hydrophobicity, alpha and turn propensities, bulky properties, compositional characteristics, local flexibility and electronic properties, are proposed to represent structures of 48 bitter-tasting dipeptides and 58 angiotensin-converting enzyme inhibitors. Characteristic parameters related to bioactivities of the peptides studied are selected by genetic algorithm, and quantitative structure-activity relationship (QSAR) models are constructed by partial least square (PLS). Our results by a leave-one-out cross validation are compared with the previously known structure representation method and are shown to give slightly superior or comparative performance. Further, two data sets are divided into training sets and test sets to validate the characterization repertoire of FASGAI. Performance of the PLS models developed by training samples by a leave-one-out cross validation and external validation for test samples are satisfying. These results demonstrate that FASGAI is an effective representation technique of peptide structures, and that FASGAI vectors have many preponderant characteristics such as straightforward physicochemical information, high characterization competence and easy manipulation. They can be further applied to investigate the relationship between structures and functions of various peptides, even proteins.

Electrochemical gate-controlled electron transport of redox-active single perylene bisimide molecular junctions

We report a scanning tunneling microscopy (STM) experiment in an electrochemical environment which studies a prototype molecular switch. The target molecules were perylene tetracarboxylic acid bisimides modified with pyridine (P-PBI) and methylthiol (T-PBI) linker groups and with bulky tert-butyl-phenoxy substituents in the bay area. At a fixed bias voltage, we can control the transport current through a symmetric molecular wire Au|P-PBI(T-PBI)|Au by variation of the electrochemical 'gate' potential. The current increases by up to two orders of magnitude. The conductances of the P-PBI junctions are typically a factor 3 larger than those of T-PBI. A theoretical analysis explains this effect as a consequence of shifting the lowest unoccupied perylene level (LUMO) in or out of the bias window when tuning the electrochemical gate potential VG. The difference in on/off ratios reflects the variation of hybridization of the LUMO with the electrode states with the anchor groups. I(T)-E(S(T)) curves of asymmetric molecular junctions formed between a bare Au STM tip and a T-PBI (P-PBI) modified Au(111) electrode in an aqueous electrolyte exhibit a pronounced maximum in the tunneling current at -0.740, which is close to the formal potential of the surface-confined molecules. The experimental data were explained by a sequential two-step electron transfer process.

Chromatin configurations in the ferret germinal vesicle that reflect developmental competence for in vitro maturation

In several mammalian species, the configuration of germinal vesicle (GV) chromatin correlates with the developmental competence of oocytes. Yet, no study has been published on the configuration of GV chromatin in ferret, nor is it known whether a specific configuration predicts meiotic competence in this species, in spite of the potential importance of ferret cloning to the study of human disease and to species conservation efforts. Here, we report on an analysis of the chromatin configuration in ferret GV oocytes and on how they correlate with meiotic development. Three distinct configurations were identified based on the degree of chromatin condensation: (1) fibrillar chromatin (FC), featuring strands of intertwined chromatin occupying most of the visible GV region; (2) intermediate condensed chromatin (ICC), characterized by dense, irregular chromatin masses throughout the GV; and (3) condensed chromatin (CC), which is highly compact and centered around the nucleolus. We also found that chromatin configuration was related to the extent of association with cumulus cells in cumulus-oocyte complexes; CC-configured oocytes were most often surrounded by a compact cumulus layer and also a compact corona but FC-configured oocytes were associated with neither. In addition, increasing chromatin condensation corresponded to an increase in oocyte diameter. Finally, following in vitro culture, significantly more CC-configured oocytes underwent maturation to meiotic metaphase II than did FC- or ICC-configured oocytes. We conclude that, in ferret, chromatin condensation is related to the sequential achievement of meiotic competencies during oocyte growth and differentiation, and thus can be used as a predictor of competence.

Use of soft hydrothermal processing to improve and recycle bedding for laboratory animals

Cage bedding for laboratory rodents can influence animal wellbeing and thus the experimental data. In addition, a large amount of used bedding containing excrement is discharged as medical waste from life science institutes and breeding companies. We developed a ground-breaking system to improve fresh bedding and recycle used bedding by applying a soft hydrothermal process with high-temperature and high-pressure dry steam. The system removes both harmful organic components and aromatic hydrocarbons that can affect animals' metabolism. The purpose of the present study was to evaluate the chemical and physical properties of the improved fresh bedding and the recycled used bedding treated by the system. The results showed that 68-99% of the predominant aromatic hydrocarbons were removed from fresh bedding treated at 0.35 MPa and 140 degrees C for 120 min ('improved bedding'). In addition, 59.4-99.0% of predominant harmful organic compounds derived from excrement were removed from used bedding treated at 0.45 MPa and 150 degrees C for 60 min ('recycled bedding'). The soft hydrothermal treatment increased the number of acidic functional groups on the bedding surface and gave it the high adsorptive efficiency of ammonia gas. Harmful substances such as microorganisms, heavy metals and pesticides decreased below the detection limit. The results clearly showed that the improved and recycled bedding is safer for laboratory rodents and has the potential to ameliorate conditions in primary and secondary enclosures (e.g. cages and animal rooms) used for maintaining laboratory animals. This process may be one of the most advanced techniques in providing an alternative to softwood and other bedding, economizing through the recycling of used bedding and reducing bedding waste from animal facilities.

Callus distraction for humeral nonunion with bone loss and limb shortening caused by chronic osteomyelitis

Nonunion of the humerus with bone loss and shortening due to osteomyelitis is rare but difficult to treat. We describe our experience with a callus distraction technique using a monolateral external fixator for the treatment of this condition. Between October 1994 and January 2004, 11 patients were treated. There were seven males and four females, with a mean age of 14 years (10 to 17). The mean bone loss was 1.9 cm (1 to 2.7) and the mean length discrepancy in the upper limb was 5.6 cm (3.5 to 8.0). The mean follow-up was for 106 months (54 to 166). The mean external fixation index was 34.8 days/cm (29.8 to 40.5). The mean lengthening was 9.5 cm (5.5 to 13.4). There were seven excellent results, three good and one poor. There were nine excellent functional results and two good. The treatment of humeral nonunion with bone loss and shortening due to osteomyelitis by callus distraction is a safe and effective means of improving function and cosmesis.

A new HLA-A*24 variant, A*2485, identified by sequence-based typing in a Chinese individual

We report the identification of the novel allele HLA-A*2485 that was found during routine high-resolution sequence-based typing of a Chinese bone marrow donor. The A*2485 allele has 1nt change from A*240201 at nt525 where T>A, codon 151 H>Q (CAT-->CAA).

Sequence-based typing characterization of the novel HLA-Cw*0340 allele in a Chinese individual

The novel human leukocyte antigen (HLA)-Cw*0340 allele was identified by sequence-based typing in a Chinese individual. This allele shows that the sequences of exons 2-3 of HLA-Cw*0340 are identical to those of HLA-Cw*0302, except for a nucleotide substitution that changes CTC to ATC at codon 95, resulting in an amino acid change from Leu to lle in the protein; this allele also shows that the sequences of exons 2-3 of HLA-Cw*0340 are identical to those of HLA-Cw*030401 or HLA-Cw*030403, except for a nucleotide substitution that changes TAC to TCC at codon 116, resulting in an amino acid change from Try to Ser in the protein.

Probing the superconducting energy gap from infrared spectroscopy on a Ba0.6K0.4Fe2As2 single crystal with Tc=37 K

We performed optical spectroscopy measurement on a superconducting Ba0.6K0.4Fe2As2 single crystal with T{c}=37 K. Formation of the superconducting energy gaps in the far-infrared reflectance spectra below T{c} is clearly observed. A flat and close to unity reflectance is observed roughly below 150 cm;{-1} for T<<T{c}, following an s-wave pairing line shape. A more rapid decrease occurs near 200 cm;{-1}, leading to a peak in the ratio of the reflectance at T<<T{c} over that for T>or=T{c}. We determined the absolute value of the penetration depth at 10 K as lambda approximately 2000+/-80 A. A spectral weight analysis shows that the Ferrell-Glover-Tinkham sum rule is satisfied at low energy scale, less than 6Delta.

Adiposity measures and blood pressure in Chinese children and adolescents

OBJECTIVE

To investigate the association of adiposity measures with blood pressure (BP) in Chinese children and adolescents.

DESIGN

A cross-sectional study.

PARTICIPANTS

1330 boys and 1170 girls aged 6-18 years from a rural population-based cohort of twins studied in Anhui, China, 1998-2000.

OUTCOME MEASURES

Adiposity measures included body mass index (BMI), total body fat and trunk fat assessed by dual-energy x-ray absorptiometry. BMI was divided into fat mass index (FMI) and lean mass index (LMI) in the analysis. Major outcomes included: systolic (S) and diastolic (D) BP. Both linear and logistic regressions were performed to assess gender-specific associations between various adiposity measures and BP, with adjustment for age and height. Generalised estimating equations were used to account for intra-twin pair correlations.

RESULTS

Mean BMI and percentage body fat in children aged 6-11 years were 14.9 kg/m(2) and 9.7%, respectively; corresponding measures in children aged 12-18 years were 17.8 kg/m(2) and 14.2%. Adiposity measures were more strongly associated with SBP (p<0.05 in all age strata) than DBP (p<0.05 only in children aged 6-11 years). Both FMI (beta = 1.26-2.37) and LMI (beta = 1.00-1.71) are associated with SBP across age and gender strata after adjustment for age and height (p<0.05).

CONCLUSIONS

These results indicate that, in this relatively lean population of Chinese children and adolescents, BP, particularly SBP, is positively associated with measures of adiposity. Of all the adiposity measures, BMI is the strongest predictor of BP.