Effect of recombinant Panton–Valentine leukocidin in vitro on apoptosis and cytokine production of human alveolar macrophages

Panton–Valentine leukocidin (PVL) is associated with rare cases of necrotizing pneumonia that occur in otherwise healthy individuals. Human alveolar macrophages (HAMs) are major effector cells in host defense against infections. However, the impact of PVL on HAMs is uncertain. We evaluated the role of PVL in cytotoxicity and production of inflammatory cytokines secreted by HAMs. HAMs were purified from bronchoalveolar lavage fluid. Recombinant PVL (rPVL) was used in the study to interfere with HAM apoptosis and cytokine production in vitro. Hoechst 33342 fluorescence staining, transmission electron microscopy examination, and flow cytometry indicated that rPVL (10 nmol/L) treatment resulted in HAMs with markedly apoptotic characteristics, and HAMs treated with rPVL at 100 nmol/L showed clear indication of necrosis. A treatment of rPVL at 10 nmol/L elicited the secretion of IL-10 by HAMs relative to untreated control cells, but there was a slight decrease in the constitutive secretion of tumor necrosis factor (TNF)-α. Our results indicate that PVL-treated samples decreased HAM viability, leading to apoptosis at low concentrations and necrosis at high concentrations. In addition, PVL-treated cells released increased amounts of IL-10 and decreased amounts of TNF-α under apoptosis-inducing concentrations. Therefore, we speculated that PVL could play a negative role in HAM function at lower concentrations.

Establishment and cryopreservation of a fibroblast cell line derived from Bengal tiger (Panthera tigris tigris)

The Bengal tiger ear marginal tissue fibroblasts cell line (BTF22), containing 157 tubes of frozen cells, was successfully established by using primary explants technique and cell cryoconservation technology. Biological analysis showed that the population doubling time (PDT) for revival cells was approximately 28 h. Measurement of LDH and MDH isoenzymes showed no cross-contamination among the cells. Karyotyping showed that the frequency of cells with chromosome number 2n = 38 was 90.6-92.2%. Tests for bacteria, fungi, viruses and mycoplasma were negative. Plasmids encoding the fluorescent proteins pEGFP-N3, pEGFP-C1, pECFP-N1, pECFP-mito, pDsRed1-N1, and pEYFP-N1 were transfected into cells to study exogenous gene expression in the cells. The plasmid transfection efficiency was between 4.4% and 31.9%. Every index of the BTF22 cell line meets all the standard quality controls of American type Culture Collection (ATCC). Not only has the germline of this important Bengal tiger species been preserved at the cell level, but also valuable material had been provided for genome, postgenome and somacloning research. Moreover, the establishment of this technical platform would provide both technical and theoretical support for storing the genetic resources of other animals and poultry at the cell level.

Early embryonic blood cells collect antigens and induce immunotolerance in the hatched chicken

Earlier experimental data in our laboratory showed that introduction of an exogenous protein into early chicken embryonic blood leads to immunotolerance of hatched chicken to that protein. However, the underlying mechanism is yet unknown. In the present study, we show that the blood cells collecting circulating antigen might contribute to the establishment of immunotolerance. In this experiment, most of the chicken embryo blood cells took up injected fluorescein isothiocyanate-BSA at approximately embryonic d 3. At the same stage, 1 microL of embryo blood was taken out and incubated with BSA. After being loaded with BSA in vitro and washed, these cells were injected back into the original embryo. The BSA-specific lymphocytes were depleted in chickens whose early embryo cells had been loaded with BSA, as evidenced by a significant decrease in anti-BSA antibody after challenge with BSA when the chickens were 3 wk old. In addition, by direct injection of BSA to embryonic d 3 embryo blood, the hatched chickens had decreased amounts of anti-trinitrophenol antibody after the chickens were challenged with trinitrophenol-BSA, indicating that the helper function of BSA-specific T cells was impaired. In conclusion, these observations suggest that some early embryo blood cells possibly collect and store antigen for the establishment of self-tolerance before the maturation of B and T cells.

Statistical model for small clusters transforming from one isomer to another

Based on the fact that the kinetic energy of one atom in small cluster still obeys the Boltzmann distribution, a statistical model is developed to predict the time consumed by a small cluster transforming from one isomer to another and is tested by vast molecular dynamics simulations of C(12) isomers transformation in helium gas at high temperatures (2000-3500 K). Extrapolating the model to lower temperatures, we found that the time for the most probable isomer of C(12) formed at 2500 K turning into the most stable one is more than 10(12) years at room temperature.

[Pulmonary nocardiosis in immunocompromised host: report of 2 cases and review of the literature]

OBJECTIVE

To investigate the clinical, imaging and pathogenic features of pulmonary nocardiosis and the drug resistance of Nocardia.

METHODS

The clinical and radiological data of 2 cases of pulmonary nocardiosis in this hospital were presented, and 32 cases reported in the Chinese literature since 1982 were reviewed.

RESULTS

Among the 34 cases of Nocardia infections, there were 26 cases of pulmonary nocardiosis, and 4 of whom died. Multiple organ infection occurred in 11 patients, including 7 with pulmonary and skin infections, 3 with pulmonary, skin and intracranial infections, and 1 with pulmonary and intracranial infections. All patients with pulmonary nocardiosis had cough. Of the 34 cases, 27 had fever, including intermittent fever in 5, and sustained fever in 22 cases. Of the 11 cases of pulmonary nocardiosis complicated with skin or intracranial dissemination, 8 patients were immunocompromised and 3 were immunocompetent (chi(2) = 2.08, P > 0.05). Three cases died in the immunocompromised group and 1 died in the immunocompetent group. Nocardia asteroides was identified in 14 cases, Nocardia brasiliensis in 4 cases, and the other 8 were not classified. In the patients with complicated skin or intracranial infections, 8 were caused by Nocardia asteroids, and 2 were caused by Nocardia brasiliensis. Chest X-ray or CT imaging of the lungs showed pleural effusion in 8, masses in 7, infiltrates in 6, cavities in 6, and nodular lesions in 5 cases. Antimicrobial susceptibility testing showed that Nocardia was sensitive to sulfonamide, amikacin, cefotaxime, ceftriaxone, minocycline, fluoroquinolones, and linezolid.

CONCLUSIONS

Immunosuppression is the most important predisposing factor for pulmonary nocardiosis. The most common pathogenic bacterium is Nocardia asteroids, which is frequently associated with disseminated lesions. The radiographic abnormalities of the lung show pleural effusion, masses, infiltration or cavity. With the increasing rate of resistance of Nocardia to the sulfonamide, the combination of antibiotic regimen according to susceptibility testing needs to be considered. Poor outcome is mostly found in immunocompromised hosts.

Stepwise regression analysis of the determinants of blood tacrolimus concentrations in Chinese patients with liver transplant

Tacrolimus (FK506) is one of the immunosuppressive drugs used effectively to prevent allograft rejection after liver transplantation. Narrow therapeutic range and individual variance in pharmacokinetics make it difficult to establish a fixed dosage for all patients. Genetic polymorphism in drug metabolizing enzymes and in transporters may influence tacrolimus exposure. A stepwise regression analysis was used to analyze the relationship between blood concentrations of tacrolimus (54 blood samples at the day of 1 week, 2 week and one month after liver transplantation) and genetic & non-genetic factors in 18 Chinese liver transplant patients. The equation of multiple stepwise regression was: Y (tacrolimus' blood concentration) = 34.534 - 0.247 (age) - 0.510 (weight) + 1.688 (dose) + 6.876 (recipient's CYP3A5 genotype) - 3.097 (donor's CYP3A5 genotype), P < 0.01. The factors impacting patient's tacrolimus blood concentrations in a descending order are weight, recipient's CYP3A5 genotype, dose, age, donor's CYP3A5 genotype. Among those, patient's weight and recipient's CYP3A5 genotype could significantly impact the blood concentration of tacrolimus. The influence of recipient's CYP3A5 gene polymorphism is much more obvious than that of donor's. Neither donor's nor recipient's MDR1 genetic polymorphisms were correlated with the blood concentration of tacrolimus.

[The effect of recombinant panton-valentine leukocidin on the production of cytokines by human alveolar macrophages]

OBJECTIVE

To investigate the effect of recombinant panton-valentine leukocidin (rPVL) on the regulation of human alveolar macrophage CD14 and IL-10 and TNF-alpha.

METHODS

Human alveolar macrophages (AM) were purified and cultured from bronchoalveolar lavage fluid. Each sample was divided into groups according to different concentrations and exposure times of rPVL. Semi-quantitative RT-PCR was used to evaluate the CD14 mRNA levels and Double-antibody-sandwich-ELISA was used to measure the IL-10 and TNF-alpha levels in AM cultures.

RESULTS

CD14 mRNA decreased after rPVL treatment in time-and concentration dependent manners. There were no statistically significant differences in CD14 mRNA among the blank control groups (F = 1.708, P > 0.05). CD14 mRNA in the T6N10 group and the T6N100 group( T = time in hours, N = concentration of rPVL/nmol/L) decreased as compared to the T6N0 group (t = 4.132, 6.818, both P < 0.001), and that in the T24N10 group and the T24N100 group also decreased as compared to the T24N0 group (t = 7.401, 11.415, both P < 0.001), indicating that the expression of CD14 was downregulated by rPVL treatment. There were also statistically significant differences in CD14 mRNA between T6N10 and T24N10 groups, T6N100 and T24N100 groups (t = 4.692, 6.019, both P < 0.001), T6N10 and T6N100 groups, T24N10 and T24N100 groups (t = 2.686, 4.014, P < 0.01 respectively), indicating that the expression of CD14 decreased as the treatment time and the concentration of rPVL increased. The IL-10 concentrations of the T24N10 and T24N100 groups increased as compared to the T24N0 group (t = 4.036, 3.941, both P < 0.01) in time-dependent and concentration-dependent manners with rPVL treatment. The TNF-alpha concentration of the T24N10 group decreased while that of the T24N100 group increased as compared to the T24N0 group (t = 2. 824, 8. 468, both P < 0.01, respectively), indicating that a lower concentration of rPVL inhibited TNF-alpha release while a higher concentration of rPVL induced release of TNF-alpha.

CONCLUSION

The results suggest that rPVL could reduce the expression of CD14 and induce disordered release of anti-inflammatory and proinflammatory cytokines by AMs, which may be one of the important mechanisms underlying the high mortality of infection with PVL-positive Staphylococcus aureus.

Pulmonary cryptococcosis in non-AIDS patients

PURPOSE

To clarify the clinical features and imaging characteristics of non-AIDS patients with pulmonary cryptococcosis.

METHODS

We retrospectively collected 15 HIV-negative patients with pathology-proved pulmonary cryptococcosis from Sep 1992 to Jan 2008. Their medical records and radiological data were reviewed and analyzed.

RESULTS

Only one patient was asymptomatic.Thirteen patients were immunocompetent and two were immunosuppressed. Three patients had associated cryptococcosis meningitis. The most common radiographic abnormalities were multiple pulmonary nodules or masses, seen in 8 and 5 cases of patients respectively. 14 patients received specific therapy for Cryptococcus neoformans. Two patients died. In the 11 patients with isolated pulmonary cryptococcosis, treatment consisted of fluconazole alone (n=7), in combination with amphotericin B (n=2), and both 5-flucytosine and amphotericin B (n=2). For the other 2 patients with cryptococcosis meningitis, one was treated with amphotericin B alone and the other with fluconazole combined with amphotericin B and 5-flucytosine.

CONCLUSIONS

Non-AIDS patients might also susceptible to cryptococcosis infection. Histological examination is the principal method of diagnosis. The most common CT findings are solitary or multiple nodules with or without cavitation in the subpleural areas of the lung.

[Research progress of neural stem cells signal transduction pathway]

OBJECTIVE

To summarize Notch, basic helix-loop-helix (bHLH) and Wnt gene signal transduction pathways in the process of differentiation and development of neural stem cells.

METHODS

The literature on the gene signal transduction pathway in the process of differentiation and development of neural stem cells was searched and then summarized and analyzed.

RESULTS

The formation of Nervous System resulted from common actions of multi-signal transduction pathways. There may exist a fixed threshold in the complicated selective system among Notch, bHLH and Wnt gene signal transduction pathways.

CONCLUSION

At present, the specific gene signal transduction pathway of multiplication and differentiation of neural stem cells is still unclear.

Diffusion characteristics of a T-type microchannel with different configurations and inlet angles

A series of symmetrical and asymmetrical microfluidic T-sensors with different inlet angles were fabricated to study the mixing characteristics of a T-type microstructure for generating concentration gradient. Computational fluid dynamics (CFD) simulations showed that the concentration gradient, transition zone and diffusion length were different for various configurations and inlet angles. Quick mix and sharp concentration gradient occurred in the asymmetrical structure with large inlet angle. The observed concentration gradients in the fabricated microchannel were consistent with the theoretical prediction. In this microstructure, stagnant zone and z-direction diffusion also affected the concentration gradient. Based on the simulation results, the microfluidic structure was optimized to generate desired concentration gradient for a cell-based study.

Frequency of CYP2D6*10 and *14 alleles and their influence on the metabolic activity of CYP2D6 in a healthy Chinese population

To study the frequency of CYP2D6(*)10 and (*)14 alleles in a healthy Chinese population, and the influence of these two alleles on the metabolic activity of CYP2D6. CYP2D6(*)10 and (*)14 genotypes of 295 healthy Chinese subjects were determined using a tetra-primer method and allele-specific amplification. CYP2D6 phenotypes of 131 subjects were determined using dextramethorphan as probe drug. There were 10 subjects with a (*)14 allele, including one homozygous for (*)14. The gene frequency of (*)10 and (*)14 alleles were 55.8 and 1.8%, respectively. The metabolic ratio (MR) of dextramethorphan in 131 subjects was 0.032+/-0.106. The MR of (*)1/(*)1, (*)1/(*)10, (*)10/(*)10, (*)1/(*)14, (*)10/(*)14, and (*)14/(*)14 groups were 0.007+/-0.012, 0.009+/-0.010, 0.042+/-0.029, 0.093, 0.11, and 1.186, respectively. The MR of subjects with (*)14 allele was higher than those of (*)1/(*)1, (*)1/(*)10, or (*)10/(*)10 groups (P<0.001). The CYP2D6(*)10 and (*)14 alleles have substantial impact on the metabolic activity of CYP2D6, and the CYP2D6(*)14 allele may be the cause of the poor metabolizer phenotype in Chinese subjects.

Dipolar effect in coherent spin mixing of two atoms in a single optical lattice site

We show that atomic dipolar effects are detectable in the system that recently demonstrated two-atom coherent spin dynamics within individual lattice sites of a Mott state. Based on a two-state approximation for the two-atom internal states and relying on a variational approach, we have estimated the spin dipolar effect. Despite the absolute weakness of the dipole-dipole interaction, it is shown that it leads to experimentally observable effects in the spin mixing dynamics.

Dynamical instability and domain formation in a spin-1 Bose-Einstein condensate

We interpret the recently observed spatial domain formation in spin-1 atomic condensates as a result of dynamical instability. Within the mean field theory, a homogeneous condensate is dynamically unstable (stable) for ferromagnetic (antiferromagnetic) atomic interactions. We find that this dynamical instability naturally leads to spontaneous domain formation as observed in several recent experiments for condensates with rather small numbers of atoms. For trapped condensates, our numerical simulations compare quantitatively to the experimental results, thus largely confirming the physical insight from our analysis of the homogeneous case.

[Comparison of two score models in predicting prognosis and renal outcome in acute renal failure]

OBJECTIVE

To compare the value of ATN-ISI (acute tubular necrosis-individual severity index) and APACHE II (acute physiology and chronic health evaluation) score models in predicting mortality and renal outcome in patients with acute renal failure (ARF).

METHODS

422 in-hospital patients with ARF were retrospectively analysed, the value in predicting prognosis and renal outcome of these two score models was compared. Renal outcome was observed three times, i.e. >or= 30 days, >or= 45 days and >or= 60 days after the occurrence of ARF and discriminant analysis was used in the study.

RESULTS

The scores of the two models both correlated significantly with the mortality of patients with ARF. When ATN-ISI scores were >or= 0.85, the mortality was 100% and it was the same with APACHE II when the scores were >or= 35. The areas under ROC curve of APACHE II and ATN-ISI were 0.817 +/- 0.021 and 0.880 +/- 0.018 respectively, suggesting good model discriminantion. For the correctly classificated rate of renal outcome, ATN-ISI was better than APACHE II at any time. When ATN-ISI scores were >or= 0.75, patients were dialysis dependent. When the scores were >or= 0.58 but less than 0.75, the patient's renal function did not recover but was not dialysis dependent; when the scores were < 0.58, the patients's renal function would recover. When APACHE II scores were >or= 26, patients were dialysis dependent. There was no cut-off score point to separate renal function recovery from renal dysfunction. However, when APACHE II scores were <or= 22, 19.6% of the patients had renal dysfunction and 80.4% of them had renal function recovered.

CONCLUSION

Both the score models are of value in predicting mortality and renal outcome in patients with ARF. ATN-ISI score model was better than APACHE II.

[Development of the chip system for measurement of red blood cell rheology]

We have developed a novel silicon microchannel system for the research of the red blood cell rheology and deformation. Recurring to many kinds of information technologies and advanced test means such as the electronic microscope, the image acquisition system and the computer processing system and by using the up-to-date Micro Electro Mechanical System (MEMS) technology, a new measuring system of red bood cell deformation is designed based on the chip and a model using the silicon microchannel to simulate capillary vessel network. It provides a real-time collection and anaysis of data which include image, speed, flow parameter, and so on. It provides printing, storage of the analysis results and patients' database management.

Field assessment of nanoscale bimetallic particles for groundwater treatment

A field demonstration was performed in which nanoscale bimetallic (Fe/Pd) particles were gravity-fed into groundwater contaminated bytrichloroethene and other chlorinated aliphatic hydrocarbons at a manufacturing site. With diameters on the order of 100-200 nm, the nanoparticles are uniquely suited to rapidly degrade redox-amenable contaminants and for optimal subsurface delivery and dispersion. Approximately 1.7 kg of the nanoparticles was fed into the test area over a 2-day period, resulting in minimal clogging of the injection well. The test area was located within a well-characterized region of the contaminant plume and included an injection well and three piezometer couplets spaced 1.5 m apart. Despite the low nanoparticle dosage, trichloroethene reduction efficiencies of up to 96% were observed over a 4-week monitoring period with the highest values observed at the injection well and adjacent piezometers. Data from the field assessment were consistent with the results of pre-injection laboratory studies, which showed rapid dechlorination of target chlorinated compounds accompanied by a sharp decrease of standard oxidation potential and an increase in pH.

Decreased +gz tolerance following lower body positive pressure: simulated push-pull effect

OBJECTIVE

The purpose of this study was to attempt to simulate the push-pull maneuver on a single-axis human centrifuge using lower body positive pressure (LBPP), and to observe the effect of the push-pull maneuver on +Gz tolerance.

METHODS

Six volunteers participated in the experiment. They were subjected to LBPP of up to 300 mm Hg for 1 min. Blood pressure (BP) and heart rate (HR) were monitored before, during and after LBPP. Immediately after LBPP, +Gz tolerance was measured on a human centrifuge.

RESULTS

During LBPP, systolic BP (SBP) and diastolic BP (DBP) increased significantly, mean arterial pressure (MAP) increased but not significantly, and HR decreased significantly. After LBPP, SBP and MAP decreased significantly, while DBP and HR decreased but not significantly. In all subjects, +Gz tolerance decreased after LBPP. The decreased value was 0.70 +/- 0.06 G, maximum 1.0 G and minimum 0.5 G.

CONCLUSION

The push-pull maneuver can be simulated on a single-axis human centrifuge using LBPP. The physiologic effects of LBPP were similar to those of -Gz. We observed that +Gz tolerance decreased after LBPP, which confirmed the push-pull effect from the experiment.

[Appraisal and analysis of heat removing characteristic of liquid cooling garment using thermal manikin]

OBJECTIVE

To analyze the relation of the design parameters and appraise the heat removing characteristic of liquid cooling garment (LCG) using thermal manikin.

METHOD

To appraise the design of LCG, the thermal manikin wearing LCG and heat insulation garment was put in the temperature cabin, then the inlet and outlet temperature of cooling liquid in the LCG were measured and the heat removed was calculated.

RESULT

The relationship between the design parameters and heat removed, and also that between the design parameters and temperature ratio efficiency were found. And the heat removed was calculated. It provided a reasonable basis for appraisal of LCG.

CONCLUSION

The design of the LCG for the EVA space suit was found to be reasonable. The flow rate regulation range was too narrow, and the change of heat removing capacity depended on the change of inlet temperature.

Synthesis and characterization of CdIn(2)S(4) nanorods by converting CdS nanorods via the hydrothermal route

The ternary semiconductor CdIn(2)S(4) nanorods were synthesized by a method based on CdS nanorods via the hydrothermal route, in which CdS nanorods were converted by reaction with InCl(3) and thiourea in aqueous solution. Transmission electron microscopy (TEM) images revealed that the typical sizes of the CdIn(2)S(4) nanorods were 10-30 nm in diameter and 200-1000 nm in length. X-ray photoelectron spectra (XPS) analysis of the surface stoichiometry (CdIn(2.03)S(4.15)) and room-temperature Raman spectrum (RS) were recorded. The influences of reaction temperature, time, and sulfur sources on the formation for CdIn(2)S(4) nanorods were investigated. A possible formation mechanism of the CdIn(2)S(4) nanorods was also proposed.

[Data analysis of 492 times centrifuge examination]

Objective. To sum up the experiences and to find the regularity of centrifuge examinations. Method. The data of nine years of centrifuge examination (from 1988 to 1996) of pilots who suffered from black out or LOC frequently were analyzed. Result. There were totally 492 times centrifuge examinations. First centrifuge examination included 229 pilots, 49 qualified, 180 unqualified. Second centrifuge examination included 263 pilots, 50 qualified, 213 unqualified. The pilots were all male. The average age of first centrifuge examination was 29.27 +/- 4.87 years. Average flying time was 1015.24 +/- 131.89 h. 68.7% of their plane was JJ-6 or above. Conclusion. Most pilots undergoing centrifuge examination these nine years were 26-35 year old, and had flown for 601-1200 h. The planes they flew are mostly high-performance fighter aircraft. Close attention must be paid to pilots under similar condition by the flight surgeon. It is recommended that the special equipment of G-tolerance training should be added to the fighter aircraft units.

Cloning and characterization of a new member of the T-box gene family

The T-box is a strongly conserved protein domain, 174 to 186 amino acids in length, that binds DNA. Many genes from many species have been shown to encode T-box domain-containing proteins. Here we report the cloning and characterization of a novel T-box gene, TBX21. The human cDNA contains an open reading frame encoding a 535-amino-acid protein with a predicted molecular mass of 58.3 kDa. Except for the T-box sequence, database searches revealed no significant homology to any known sequences at the nucleotide or protein level. In addition to the human cDNA sequence, we report the cDNA sequence of the murine homologue, the structure and organization of the murine Tbx21 gene, and its localization to mouse chromosome 11. TBX21 expression was detected in peripheral blood lymphocytes, spleen, lung, and natural killer cells.