Induction of CD4+CD25+ T cells and control of cardiac allograft rejection by CD40/CD40L costimulatory pathway blockade in mice

BACKGROUND

Rejection is a major problem in organ transplantation. We speculated that dendritic cells (DCs) with low expression of CD40 may inhibit T-cell responses providing protective effects on organ transplantions.

METHODS

RNA interference (RNAi) is an effective approach to degrade RNA levels of a target gene. We used RNAi to reduce CD40 levels in mouse bone marrow-derived DCs. Allogeneic T-lymphocyte proliferation stimulated by DCs was assessed in mixed lymphocyte reactions. A mouse model of heterotopic abdominal heart transplantation was performed to evaluate survival times and histologic grade of acute rejection at 7 days after transplantation. CD4(+)CD25(+) regulatory T cells (Tregs) in peripheral blood were quantified by flow cytometry.

RESULTS

Mouse DCs with reduced CD40 expression lowered the proliferation of recipient T cells. More DCs with silenced CD40 delayed cardiac allograft rejection.

CONCLUSIONS

Reduction of CD40 in DCs induced peripheral Tregs and delayed cardiac allograft rejection.

Smooth muscle cell phenotypic diversity between dissected and unaffected thoracic aortic media

AIM

Smooth muscle cell (SMC) phenotypic switching in the aortic media may play a critical role in the pathogenesis of thoracic aortic dissection (TAD). However, few investigations are available and most of the observations are based on histological examinations without in vitro evidence. This study, which was performed both in vivo and in vitro, was designed to investigate SMC phenotypic diversity between dissected and unaffected aortic media.

METHODS

Using optimized explant technique, aortic medial SMCs were obtained from patients with TAD and controls. In vivo and in vitro expression of α-smooth muscle actin (α-SMA), smooth muscle-myosin heavy chain 2 (SM-MHC-2), smooth muscle-calponin (SM-Calponin), Vimentin, osteopontin (OPN) and non-muscle myosin heavy chain B (SMemb) were evaluated by immunostaining and immunoblotting. SMC proliferation was also analyzed.

RESULTS

Although the majority of SMCs from the dissected media displayed an elongated, spindle- or triangle-like shape as control SMCs, there were some oval or flat, quadrate cells in the dissection cultures. In contrast with controls, SMCs derived from the dissected media uniformly showed the negative staining for the contractile proteins and the intense staining for the synthetic markers. Similarly, in vitro protein levels of α-SMA, SM-MHC-2, SM-Calponin and Vimentin were significantly decreased to 60.1% (P<0.05), 12.0% (P<0.01), 23.1% (P<0.01) and 32.5% (P<0.01) respectively, whereas those of OPN and SMemb were markedly elevated by5.7- and 10.3-fold respectively (P<0.01 for both). In vivo expression of the phenotypic markers showed the parallel results. Furthermore, SMCs derived from the dissected media exhibited the enhanced proliferation (P<0.05).

CONCLUSION

We have established a simple and potent method to acquire SMCs from the dissected and unaffected aortic media. Compared to the contractile SMCs in the unaffected media, those in the dissected media manifest phenotypic switching from the contractile to the synthetic type. The primary cultures can be subsequently used as in vitro models and contribute to further elucidating the etiopathogenesis of TAD.

Effects of footwear on impact forces and soft tissue vibrations during drop jumps and unanticipated drop landings

The purpose of this study was to explore the footwear effects on impact forces and soft-tissue vibrations during landing. 12 male basketball players were instructed to perform drop jumps and unanticipated drop landings from 30 cm, 45 cm, and 60 cm heights in basketball shoes (BS) and control shoes (CS). 3D kinematics, ground reaction force (GRF), and soft-tissue vibrations of the leg, and acceleration of the shoe heel counter were measured simultaneously. The results showed no significant shoe effect on the characteristics of the impact force nor on the resonance frequency and peak transmissibility of soft-tissue vibrations during the impact phase of the drop jump. For the unanticipated drop landings, however, the magnitude of both peak GRF and peak loading rate were significantly lower with BS compared to CS across all 3 heights (p<0.05); meanwhile BS showed a significant decrease in GRF frequency compared to CS at 45 cm (p<0.05) and 60 cm (p<0.01) heights. Furthermore, the peak transmissibility in BS was significantly lower than that in CS for both the quadriceps and hamstrings during the 60 cm unanticipated drop landing (p<0.05). These findings provide preliminary evidence suggesting that if the neuromuscular system fails to prepare properly for an impact during landing, a shoe intervention may be an effective method for minimizing impact force and reducing soft tissue resonance.

Microbiologic characteristics of pathogenic bacteria from hospitalized trauma patients who survived Wenchuan earthquake

The purpose of this study is to investigate the microbiological characterization of pathogenic bacteria isolated from trauma patients after Wenchuan earthquake in 2008. Most infections were identified in the patients over 60 years of age, with an incidence rate of 78.5%, and more infections in wound (43.3%) and respiratory tract (37.1%) sites were identified. A total of 97 non-duplicated clinical pathogens were isolated from 91 trauma patients. Of those pathogens, 62 (63.9%) were Gram-negative bacilli, 23 (23.7%) were Gram-positive cocci, 9 (9.3%) were fungi, and 3 (3.1%) were anaerobes, such as Clostridium perfringens. The distribution spectrum of pathogens isolated from trauma patients after earthquake was different to that from non-earthquake trauma patients in our hospital at the same time. The most prevalent pathogenic isolates were Escherichia coli (15.4%), Acinetobacter baumannii (14.4%), Staphylococcus aureus (12.3%), Burkholderia cepacia (11.3%), and Enterococcus spp. (9.3%). The drug susceptibility results showed that most of the Gram-negative bacilli, except for Pseudomonas aeruginosa and Burkholderia cepacia, were susceptible to imipenem, but resistant to the first- and the second-generation cephalosporins. Most of the Gram-positive cocci were susceptible to vancomycin, linezolid, and Synercid/dalfopristin. Characteristics of pathogenic bacterium isolated from trauma patients after earthquake have been demonstrated which play an important role in the appropriate treatment of infections.

True reference nanosensor realized with silicon nanowires

Conventional gate oxide layers (e.g., SiO(2), Al(2)O(3), or HfO(2)) in silicon field-effect transistors (FETs) provide highly active surfaces, which can be exploited for electronic pH sensing. Recently, great progress has been achieved in pH sensing using compact integrateable nanowire FETs. However, it has turned out to be much harder to realize a true reference electrode, which--while sensing the electrostatic potential--does not respond to the proton concentration. In this work, we demonstrate a highly effective reference sensor, a so-called reference FET, whose proton sensitivity is suppressed by as much as 2 orders of magnitude. To do so, the Al(2)O(3) surface of a nanowire FET was passivated with a self-assembled monolayer of silanes with a long alkyl chain. We have found that a full passivation can be achieved only after an extended period of self-assembling lasting several days at 80 °C. We use this slow process to measure the number of active proton binding sites as a function of time by a quantitative comparison of the measured nonlinear pH-sensitivities to a theoretical model (site-binding model). Furthermore, we have found that a partially passivated surface can sense small changes in the number of active binding sites reaching a detection limit of δN(s) ≈ 170 μm(-2) Hz(-1/2) at 10 Hz and pH 3.

Cell permeability, migration, and reactive oxygen species induced by multiwalled carbon nanotubes in human microvascular endothelial cells

Multiwalled carbon nanotubes (MWCNT) have elicited great interest in biomedical applications due to their extraordinary physical, chemical, and optical properties. Intravenous administration of MWCNT-based medical imaging agents and drugs in animal models was utilized. However, the potential harmful health effects of MWCNT administration in humans have not yet been elucidated. Furthermore, to date, there are no apparent reports regarding the precise mechanisms of translocation of MWCNT into target tissues and organs from blood circulation. This study demonstrates that exposure to MWCNT leads to an increase in cell permeability in human microvascular endothelial cells (HMVEC). The results obtained from this study also showed that the MWCNT-induced rise in endothelial permeability is mediated by reactive oxygen species (ROS) production and actin filament remodeling. In addition, it was found that MWCNT promoted cell migration in HMVEC. Mechanistically, MWCNT exposure elevated the levels of monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule 1 (ICAM-1) in HMVEC. Taken together, these results provide new insights into the bioreactivity of MWCNT, which may have implications in the biomedical application of MWCNT in vascular targeting, imaging, and drug delivery. The results generated from this study also elucidate the potential adverse effects of MWCNT exposure on humans at the cellular level.

Cell permeability, migration, and reactive oxygen species induced by multiwalled carbon nanotubes in human microvascular endothelial cells

Multiwalled carbon nanotubes (MWCNT) have elicited great interest in biomedical applications due to their extraordinary physical, chemical, and optical properties. Intravenous administration of MWCNT-based medical imaging agents and drugs in animal models was utilized. However, the potential harmful health effects of MWCNT administration in humans have not yet been elucidated. Furthermore, to date, there are no apparent reports regarding the precise mechanisms of translocation of MWCNT into target tissues and organs from blood circulation. This study demonstrates that exposure to MWCNT leads to an increase in cell permeability in human microvascular endothelial cells (HMVEC). The results obtained from this study also showed that the MWCNT-induced rise in endothelial permeability is mediated by reactive oxygen species (ROS) production and actin filament remodeling. In addition, it was found that MWCNT promoted cell migration in HMVEC. Mechanistically, MWCNT exposure elevated the levels of monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule 1 (ICAM-1) in HMVEC. Taken together, these results provide new insights into the bioreactivity of MWCNT, which may have implications in the biomedical application of MWCNT in vascular targeting, imaging, and drug delivery. The results generated from this study also elucidate the potential adverse effects of MWCNT exposure on humans at the cellular level.

ZnO nanorod array/CuAlO2 nanofiber heterojunction on Ni substrate: synthesis and photoelectrochemical properties

A novel ZnO nanorod array (NR)/CuAlO(2) nanofiber (NF) heterojunction nanostructure was grown on a substrate of Ni plates using sol-gel synthesis for the NFs and hydrothermal reaction for the NRs. Compared with a traditional ZnO/CuAlO(2) laminar film nanostructure, the photocurrent of this fibrous network heterojunction is significantly increased. A significant blue-shift of the absorption edge and a favorable forward current to reverse current ratio at applied voltages of -2 to +2 V were observed in this heterojunction with the increase of Zn(2+) ion concentration in the hydrothermal reaction. Furthermore, the photoelectrochemical properties were investigated and the highest photocurrent of 3.1 mA cm(-2) was obtained under AM 1.5 illumination with 100 mW cm(-2) light intensity at 0.71 V (versus Ag/AgCl). This novel 3D fibrous network nanostructure plays an important role in the optoelectronic field and can be extended to other binary or ternary oxide compositions for various applications.

Detection of rpoB, katG and inhA gene mutations in Mycobacterium tuberculosis clinical isolates from Chongqing as determined by microarray

The emergence of multidrug-resistance Mycobacterium tuberculosis is an increasing threat to tuberculosis control programmes. Susceptibility testing of Mycobacterium tuberculosis complex isolates by traditional methods requires a minimum of 14 days. This can be reduced significantly if molecular analysis is used. DNA sequencing is a good method for detecting mutation, but cannot be used routinely because of its relatively high cost. A sensitive and specific microarray has been designed to detect mutations in the rifampin resistance determining region of rpoB and loci in katG and inhA associated with isoniazid (INH) resistance. A panel of Mycobacterium tuberculosis isolates containing 13 different rpoB genotypes, two mutation genotypes within codon 315 of katG and one mutation genotypes at inhA was used to validate the microarray. The results obtained indicate that 100% of rifampicin-resistant M. tuberculosis strains isolated in Chongqing had rpoB mutations, with 531-Ser and 526-His being the most common positions substituted. Of the total 50 INH resistant isolates, 82% had a katG315 mutation and 18% had an inhA mutation. All the mutations detected by the microarray method were also confirmed by conventional DNA sequencing. It is demonstrated that the microarray is an efficient, specialized technique and can be used as a rapid method for detecting rifampin and isoniazid resistance.

An approach to the correlation between vitiligo and autoimmune thyroiditis in Chinese children

BACKGROUND

Vitiligo is a common skin depigmenting disease, which is thought to have, at least partly, an autoimmune aetiology.

AIM

To explore the correlation between paediatric vitiligo and other associated diseases, with an emphasis on autoimmune thyroiditis (AT).

METHODS

In total, 363 paediatric patients (198 boys, 165 girls) with vitiligo and 93 healthy children (55 boys, 38 girls) were screened for autoimmune thyroiditis. The two groups were matched for age and gender. Children with vitiligo were split into two groups according to type (segmental and nonsegmental vitiligo). Demographic data, clinical features and examinations were recorded using questionnaires. Thyroid function tests including free triiodothyronine, free thyroxine and thyroid-stimulating hormone were performed. Anti-thyroid peroxidase antibody) and anti-thyroglobulin antibody levels were assessed as well. Other associated diseases were also monitored in this study.

RESULTS

Of the 363 patients, 43 (11.8%) had abnormal levels of studied thyroid parameters, compared with 4 of the 93 controls (4.3%); the difference was significant (P = 0.04). The alterations of thyroid parameters and the incidence of AT in patients with nonsegmental vitiligo were both significantly different (P < 0.05, P = 0.04) relative to the segmental vitiligo group. Of the 363 patients, 67 (18.5%) had other associated diseases. There were no differences in the rates of other associated diseases between patients with segmental vitiligo and those with nonsegmental vitiligo (P > 0.05).

CONCLUSIONS

A significant incidence of thyroid dysfunction was found in paediatric patients with nonsegmental vitiligo. As vitiligo usually appears before the development of the thyroid disease, it may be advantageous to screen thyroid functions and antibody levels in all paediatric patients with vitiligo, especially those with nonsegmental vitiligo.

Development of community nursing in Zhejiang Province, China: a report of the driving measures

BACKGROUND

Community nursing is playing an important role in health care worldwide.

METHODS

We reviewed recent developments in community nursing in the Zhejiang province of China and reported that the locally tailored practical guidelines, education programmes and management models are the driving measures for promoting local community nursing.

RESULTS

In 2008, Zhejiang had 1200 community primary health-care service centres, an increase of 56% and 6789 service stations, a twofold increase, compared with 2004. At present, 27 000 community nurses, together with the same number of family doctors, are working in community health-care service centres and stations. Community nursing in Zhejiang has grown not only by numbers but also by the greatly improved infrastructures and functions of its community primary health care.

CONCLUSION

It is the multi-pronged approach that has led to the change being successful in a local health-care system.

Correlation of population parameters leading to power differences in association studies with population stratification

The power of statistical tests to measure effect sizes in the presence of population stratification is an important issue for the design and analysis of population-based association studies. Comparisons of statistical tests have shown that the power of different statistical approaches varies in different genetic scenarios. However, the impact of stratified population parameters on statistical power is not yet understood in a general statistical framework, particularly the impact of correlated population parameters. To investigate such impact in detail, we implemented a genetic model for population-based association studies with stratified samples and evaluated the impact on power with different genetic scenarios. The investigation shows that correlation between disease prevalence and risk allele frequency among subpopulations impacts statistical power. In a model with five subpopulations and moderate population divergence (Fst= 0.01), the correlation accounts for more than 85% of power difference. Our results also show that the estimation of genetic effect for candidate loci is biased by population divergence. Beneficial alleles could be wrongly characterized as risk alleles when prevalence differences and divergences of risk loci are large among subpopulations.

Angiotensinogen gene G-6A polymorphism influences idiopathic pulmonary fibrosis disease progression

Angiotensin II is a growth factor that plays a key role in the physiopathology of idiopathic pulmonary fibrosis (IPF). A nucleotide substitution of an adenine instead of a guanine (G-6A) in the proximal promoter region of angiotensinogen (AGT), the precursor of angiotensin II, has been associated with an increased gene transcription rate. In order to investigate whether the G-6A polymorphism of the AGT gene is associated with IPF development, severity and progression, the present study utilised a case-control study design and genotyped G-6A in 219 patients with IPF and 224 control subjects. The distribution of G-6A genotypes and alleles did not significantly differ between cases and controls. The G-6A polymorphism of the AGT gene was not associated with disease severity at diagnosis. The presence of the A allele was strongly associated with increased alveolar arterial oxygen tension difference during follow-up, after controlling for the confounding factors. Higher alveolar arterial oxygen tension changes over time were observed in patients with the AA genotype (0.37+/-0.7 mmHg (0.049+/-0.093 kPa) per month) compared to GA genotype (0.12+/-1 mmHg (0.016+/-0.133 kPa) per month) and GG genotype (0.2+/-0.6 mmHg (0.027+/-0.080 kPa) per month). G-6A polymorphism of the angiotensinogen gene is associated with idiopathic pulmonary fibrosis progression but not with disease predisposition. This polymorphism could have a predictive significance in idiopathic pulmonary fibrosis patients.

Synergistic antitumor efficacy of suicide/ePNP gene and 6-methylpurine 2'-deoxyriboside via Salmonella against murine tumors

Some anaerobes and facultative anaerobes have been used in tumor-specific gene therapy by reason of their selective growth in tumors. In this work, we aimed to evaluate the anticancer efficacy of attenuated Salmonella typhimurium as a carrier to deliver the Escherichia coli purine nucleoside phosphorylase (ePNP) gene for GDEPT (gene-directed enzyme-prodrug therapy). A live attenuated purine-auxotrophic strain of S. typhimurium (SC36) was used to carry the pEGFP-C1-ePNP vector that contains a green fluorescent protein (GFP) and an ePNP gene under the control of the human cytomegalovirus (CMV) promoter. The function of the ePNP expression vector was confirmed in vitro using the enzymic conversion of 6-methylpurine 2'-deoxyriboside (MePdR) into 6-methylpurine. We also observed a high bystander effect induced by the ePNP/MePdR system with a very low proportion (1%) of ePNP-positive cells. The killing effect and increased apoptosis induced by SC/ePNP (SC36 carrying the ePNP expression vector) infection were detected by cytotoxicity assay and PI staining flow cytometry analysis, in combination with MePdR administration. Furthermore, SC/ePNP was administered orally into mice bearing melanomas or pulmonary tumors, and its anti-tumor effect was evaluated. When the tumor was huge (500 mm(3)) at the beginning of MePdR administration, SC/ePNP plus MepdR significantly inhibited tumor growth by about 59-80% and prolonged survival of mice. Complete tumor regression and long-term cure were achieved by MePdR administration, even when the tumor was large (100 mm(3)) at the beginning of MePdR treatment. Our data support a hopeful view that tumor-targeting SC36 could improve antitumor efficacy of the ePNP/MePdR system due to its preferential accumulation and anticancer activity in tumors.

Ultrasonic-assisted synthesis of highly dispersed MoO3 nanospheres using 3-mercaptopropyltrimethoxysilane

With ultrasonic irradiation as assistance, highly dispersed MoO(3) nanospheres were synthesized using silane coupling agent 3-mercaptopropyltrimethoxysilane HS-(CH(2))(3)Si(OCH(3))(3) (MPTS) as figuration agent. The results of X-ray powder diffractometer (XRD) showed that the precursor was hexagonal molybdenum oxide hydrate (MoO(3).0.55H(2)O). It was converted into orthorhombic MoO(3) after annealed at 400 degrees C for 2h. Transmission electron microscopy (TEM) showed that MoO(3).0.55H(2)O and MoO(3) nanoparticles were spherical with particle-size distribution of ca. 30-80 nm and 25-75 nm, respectively. Results indicated that MPTS and ultrasonic irradiation played important role in formation of highly dispersed MoO(3) nanospheres. X-ray photoelectron spectroscopy (XPS) was also adopted to confirm the growth mechanism. The possible cause of formation was based on dispersion function of ultrasonic irradiation and figuration of MPTS.

Growth of Dumbbell-like ZnO Microcrystals under Mild Conditions and their Photoluminescence Properties

Large-scale uniform dumbbell-like ZnO microcrystals were successfully synthesized via a facile solution method under mild conditions. The as-prepared dumbbells, with lengths of 3.5-5.4 microm and diameters of 1.3-1.8 microm, possess a single-crystal hexagonal structure and grow along the [0001] direction. The influence of the reactant concentration on the size and shapes of the ZnO samples had been studied, and the results revealed that the reactant concentration plays a crucial role in determining final morphologies of the samples. Moreover, the evolution process of the dumbbell-like ZnO microcrystals was viewed by field-emission scanning electron microscopy (FE-SEM) characterization, and a possible formation mechanism was proposed. In addition, optical properties of the ZnO samples prepared at different reaction times were also investigated by photoluminescence (PL) spectroscopy. The room-temperature PL spectrum of the dumbbell-like ZnO microcrystals shows a strong UV emission peak. The UV emission is further identified to originate from the radiative free-exciton recombination by the temperature-dependent PL.

Results from the ARTEMIS DISK Global Antifungal Surveillance study, 1997 to 2005: an 8.5-year analysis of susceptibilities of Candida species and other yeast species to fluconazole and voriconazole determined by CLSI standardized disk diffusion testing

Fluconazole in vitro susceptibility test results for 205,329 yeasts were collected from 134 study sites in 40 countries from June 1997 through December 2005. Data were collected for 147,776 yeast isolates tested with voriconazole from 2001 through 2005. All investigators tested clinical yeast isolates by the CLSI M44-A disk diffusion method. Test plates were automatically read and results recorded with a BIOMIC image analysis system. Species, drug, zone diameter, susceptibility category, and quality control results were collected quarterly. Duplicate (same patient, same species, and same susceptible-resistant biotype profile during any 7-day period) and uncontrolled test results were not analyzed. Overall, 90.1% of all Candida isolates tested were susceptible (S) to fluconazole; however, 10 of the 22 species identified exhibited decreased susceptibility (<75% S) on the order of that seen with the resistant (R) species C. glabrata and C. krusei. Among 137,487 isolates of Candida spp. tested against voriconazole, 94.8% were S and 3.1% were R. Less than 30% of fluconazole-resistant isolates of C. albicans, C. glabrata, C. tropicalis, and C. rugosa remained S to voriconazole. The non-Candida yeasts (8,821 isolates) were generally less susceptible to fluconazole than Candida spp. but, aside from Rhodotorula spp., remained susceptible to voriconazole. This survey demonstrates the broad spectrum of these azoles against the most common opportunistic yeast pathogens but identifies several less common yeast species with decreased susceptibility to antifungal agents. These organisms may pose a future threat to optimal antifungal therapy and emphasize the importance of prompt and accurate species identification.

Modelling the roles of MAO and SSAO in glucose transport

Amine oxidase substrates such as benzylamine and methylamine have been shown to stimulate glucose uptake by increasing the recruitment of the glucose transporter GLUT4 from vesicles within the cell to the cell surface. Inhibition of this effect by the presence of semicarbazide and catalase led to the suggestion that the process is mediated by the H(2)O(2) produced in the oxidation of these amines. Tyramine, which is a substrate for both MAO and SSAO, can also stimulate this process and in that case both MAO and SSAO inhibitors attenuate the effect. Benzylamine does not occur physiologically and tyramine is normally present in only very low amounts. We have suggested that adrenaline, which also stimulates glucose metabolism through adrenoceptors, may act as the physiological substrate for GLUT4 recruitment. It is a substrate for MAO but not SSAO. However, oxidation of adrenaline by MAO releases both H(2)O(2) and methylamine for further oxidation by SSAO. In order to gain a fuller understanding of this process we have performed simulation studies that may be used to assess the contributions of the amine oxidases to the process under a variety of conditions. The results are consistent with the experimentally observed behaviour. This approach not only helps to establish the feasibility of this process but also allows behaviour prediction and the identification of further experimental approaches.