Vitamin D receptor genetic polymorphisms and tuberculosis: updated systematic review and meta-analysis

BACKGROUND

Host genetic susceptibility has been suggested as one of the most important explanations for inter-individual differences in tuberculosis (TB) risk. The vitamin D receptor (VDR) gene has been studied as a candidate locus due to genetic polymorphisms that affects the activity of the receptor and subsequent downstream vitamin D-mediated effects.

METHODS

We reviewed published studies on VDR polymorphisms and TB susceptibility up to 15 April 2009 and quantitatively summarised associations of the most widely studied polymorphisms (FokI, TaqI, ApaI and BsmI) using meta-analysis.

RESULTS

A total of 23 eligible studies were included in this review. Heterogeneous results were observed, which may be partly explained by the differences between populations. Among Asians, the FokI ff genotype showed a pronounced positive association (OR 2.0, 95%CI 1.3-3.2), a significant inverse association was observed for the BsmI bb genotype (OR 0.5, 95%CI 0.4-0.8), and marginal significant associations were found for TaqI and ApaI polymorphisms. However, none of the polymorphisms was significantly related to TB among Africans or South Americans.

CONCLUSIONS

The association of VDR polymorphisms with risk of TB observed in our analyses supports the hypothesis that vitamin D deficiency might play a role as risk factor during the development of TB.

PDGF-B gene therapy accelerates bone engineering and oral implant osseointegration

Platelet-derived growth factor-BB (PDGF-BB) stimulates repair of healing-impaired chronic wounds such as diabetic ulcers and periodontal lesions. However, limitations in predictability of tissue regeneration occur due in part to transient growth factor bioavailability in vivo. Here, we report that gene delivery of PDGF-B stimulates repair of oral implant extraction socket defects. Alveolar ridge defects were created in rats and were treated at the time of titanium implant installation with a collagen matrix containing an adenoviral (Ad) vector encoding PDGF-B (5.5×10⁸ or 5.5×10⁹ pfu/ml), Ad encoding luciferase (Ad-Luc; 5.5×10⁹ pfu/ml; control) or recombinant human PDGF-BB protein (rhPDGF-BB, 0.3 mg/ml). Bone repair and osseointegration were measured via backscattered SEM, histomorphometry, microcomputed tomography, and biomechanical assessments. Further, a panel of local and systemic safety assessments was performed. Results demonstrated bone repair was accelerated by Ad-PDGF-B and rhPDGF-BB delivery compared to Ad-Luc, with the high dose of Ad-PDGF-B more effective than the low dose. No significant dissemination of the vector construct or alteration of systemic parameters was noted. In summary, gene delivery of Ad-PDGF-B demonstrates regenerative and safety capabilities for bone tissue engineering and osseointegration in alveolar bone defects comparable to rhPDGF-BB protein delivery in vivo.

Prevalence of human respiratory viruses in adults with acute respiratory tract infections in Beijing, 2005-2007

To determine the aetiological role and epidemiological profile of common respiratory viruses in adults with acute respiratory tract infections (ARTIs), a 2-year study was conducted in Beijing, China, from May 2005 to July 2007. Nose and throat swab samples from 5808 ARTI patients were analysed by PCR methods for common respiratory viruses, including influenza viruses (IFVs) A, B, and C, parainfluenza viruses (PIVs) 1-4, enteroviruses (EVs), human rhinoviruses (HRVs), respiratory syncytial virus (RSV), human metapneumovirus (HMPV), human coronaviruses (HCoVs) OC43, 229E, NL63, and HKU1, and adenoviruses (ADVs). Viral pathogens were detected in 34.6% of patient samples, and 1.6% of the patients tested positive for more than one virus. IFVs (19.3%) were the dominant agents detected, followed by HRVs (6.5%), PIVs (4.3%), EVs (3.2%), and HCoVs (1.1%). ADVs, RSV and HMPV were also detected (<1%). The viral detection rates differed significantly between infections of the lower and upper respiratory tracts in the sample population: PIVs, the second most commonly detected viral agents in lower acute respiratory tract infections (LRTIs), were more prevalent than in upper acute respiratory tract infections, indicating that the pathogenic role of PIVs in LRTIs should be investigated. Currently, this study is the largest-scale investigation of respiratory virus infections in China with multiple agent detection, providing baseline data for further studies of respiratory virus infections in adults with ARTIs.

Meta-analysis: prevalence of HIV infection and syphilis among MSM in China

OBJECTIVES

The prevalence of HIV/AIDS and other sexually transmitted diseases is rapidly rising among men who have sex with men (MSM) in China. The aim is to systematically review the published studies and summarise the estimates of HIV prevalence among MSM in China.

METHODS

Published articles, both in English and in Chinese, on HIV prevalence among MSM in China until 15 September 2008 were systematically reviewed. Meta-analysis was used to quantitatively summarise the estimates, and the prevalence of syphilis presented in the included studies was also analysed.

RESULTS

Twenty-six eligible studies, published during 2001-2008, were included in this review. Their results were frequently heterogeneous. The meta-analyses showed that MSM form a high-risk population for HIV infection in China with a summary prevalence of 2.5% (95% CI 0.9% to 3.3%). A much higher prevalence of syphilis (9.1%) may indicate a potential of more severe HIV epidemic in the future because of their common high-risk behaviours.

CONCLUSIONS

MSM are a high-risk population for HIV infection in China. An effective strategy for prevention and control is required for this specific population. Differences between sampling methods, sample sizes and study locations may explain some of the inconsistencies found in the included studies.

Platelet-derived growth factor-B gene delivery sustains gingival fibroblast signal transduction

BACKGROUND AND OBJECTIVE

Platelet-derived growth factor-BB is a potent mediator of tooth-supporting periodontal tissue repair and regeneration. A limitation of the effects of topical platelet-derived growth factor-BB application is its short half-life in vivo. Gene therapy has shown strong promise for the long-term delivery of platelet-derived growth factor in both skin ulcer healing and periodontal tissue engineering. However, little is known regarding the extended effects of platelet-derived growth factor-B on cell signaling via gene delivery, especially at the level of phosphorylation of intracellular kinases. This study sought to evaluate the effect of gene transfer by Ad-PDGF-B on human gingival fibroblasts (HGFs) and the subsequent regulation of genes and cell-surface proteins associated with cellular signaling.

MATERIAL AND METHODS

HGFs from human subjects were treated by adenoviral PDGF-B, PDGF-1308 (a dominant negative mutant of PDGF) and recombinant human platelet-derived growth factor-BB, and then incubated in serum-free conditions for various time points and harvested at 1, 6, 12, 24, 48, 72 and 96 h. Exogenous PDGF-B was measured by RT-PCR and Western blot. Cell proliferation was evaluated by [methyl-3H]thymidine incorporation assay. We used proteomic arrays to explore phosphorylation patterns of 23 different intracellular kinases after PDGF-B gene transfer. The expression of alpha and beta PDGFR and Akt were measured by Western blot analysis.

RESULTS

Sustained in vitro expression of PDGF-B in HGFs by Ad-PDGF-B transduction was seen at both the mRNA and protein levels. Compared to rhPDGF-BB and Ad-PDGF-1308, Ad-PDGF-B maintained cell growth in serum-free conditions, with robust increases in DNA synthesis. Gene delivery of PDGF-B also prolonged downregulation of the growth arrest specific gene (gas) PDGF alpha R. Of the 23 intracellular kinases that we tested in proteomic arrays, Akt revealed the most notable long-term cell signaling effect as a result of the over-expression of Ad-PDGF-B, compared with pulse recombinant human platelet-derived growth factor BB. Prolonged Akt phosphorylation was induced by treatment with Ad-PDGF-B, for at least up to 96 h.

CONCLUSION

These findings further demonstrate that gene delivery of PDGF-B displays sustained signal transduction effects in human gingival fibroblasts that are higher than those conveyed by treatment with recombinant human platelet-derived growth factor-BB protein. These data on platelet-derived growth factor gene delivery contribute to an improved understanding of these pathways that are likely to play a role in the control of clinical outcomes of periodontal regenerative therapy.

Global gene expression of Trichophyton rubrum in response to PH11B, a novel fatty acid synthase inhibitor

AIMS

To determine the transcriptional responses of Trichophyton rubrum to the artificial substance, PH11B.

METHODS AND RESULTS

The broth microdilution assay for antifungal susceptibility testing of dermatophytes was used to measure the minimum inhibitory concentration (MIC) of PH11B. cDNA microarray technology and real-time RT-PCR were used to study the transcriptional responses of T. rubrum to PH11B. The MIC determined was 16 microg ml(-1). The analysis of microarray data revealed that 787 genes were affected. Transcript levels from 476 genes increased at least two times, while 311 gene transcript levels decreased at least two times.

CONCLUSIONS

PH11B has strong antifungal activity and the transcriptional response of T. rubrum to PH11B was determined.

SIGNIFICANCE AND IMPACT OF THE STUDY

This microarray data set provides an analysis of gene expression of T. rubrum under PH11B treatment. The data provide an insight into the various metabolic processes altered or activated by PH11B. This study provided an insight into the action mode of the PH11B on T. rubrum.

Overexpression of the apple MpNPR1 gene confers increased disease resistance in Malus x domestica

The NPR1 gene plays a pivotal role in systemic acquired resistance in plants. Its overexpression in Arabidopsis and rice results in increased disease resistance and elevated expression of pathogenesis-related (PR) genes. An NPR1 homolog, MpNPR1-1, was cloned from apple (Malus x domestica) and overexpressed in two important apple cultivars, Galaxy and M26. Apple leaf pieces were transformed with the MpNPR1 cDNA under the control of the inducible Pin2 or constitutive Cauliflower mosaic virus (CaMV)35S promoter using Agrobacterium tumefaciens. Overexpression of MpNPR1 mRNA was shown by reverse transcriptase-polymerase chain reaction. Activation of some PR genes (PR2, PR5, and PR8) was observed. Resistance to fire blight was evaluated in a growth chamber by inoculation of the shoot tips of our own rooted 30-cm-tall plants with virulent strain Ea273 of Erwinia amylovora. Transformed Galaxy lines overexpressing MpNPR1 had 32 to 40% of shoot length infected, compared with 80% in control Galaxy plants. Transformed M26 lines overexpressing MpNPR1 under the control of the CaMV35S promoter also showed a significant reduction of disease compared with control M26 plants. Some MpNPR-overexpressing Galaxy lines also exhibited increased resistance to two important fungal pathogens of apple, Venturia inaequalis and Gymnosporangium juniperi-virginianae. Selected transformed lines have been propagated for field trials for disease resistance and fruit quality.

Control of hydrogen partial pressures on the rates of syntrophic microbial metabolisms: a kinetic model for butyrate fermentation

A new model describing the rate of syntrophic butyrate fermentation is constructed based on a thermodynamically consistent rate law and the metabolic pathway. This model takes into account the mechanism of reverse electron transfer and proposes that the net amount of energy saved by microorganisms as ATP depends on hydrogen partial pressures in the environment. Hydrogen partial pressures thus control not only the energy available in the environment but also the energy conserved by microorganisms. This new model predicts the rates of butyrate fermentation as a product of a kinetic factor and a thermodynamic potential factor: the kinetic factor describes how butyrate concentration controls the rates; the thermodynamic factor accounts for how the thermodynamic driving force controls the rates. Increases in hydrogen partial pressures decrease the energy available, lowering the driving force and fermentation rates. To maintain butyrate fermentation at significant rates, microorganisms decrease the amount of energy conserved, maximizing the driving force. Application of the new model demonstrates that the thermodynamic driving force is a dominant factor in controlling the rates of butyrate fermentation.

Current concepts in periodontal bioengineering

Repair of tooth supporting alveolar bone defects caused by periodontal and peri-implant tissue destruction is a major goal of reconstructive therapy. Oral and craniofacial tissue engineering has been achieved with limited success by the utilization of a variety of approaches such as cell-occlusive barrier membranes, bone substitutes and autogenous block grafting techniques. Signaling molecules such as growth factors have been used to restore lost tooth support because of damage by periodontal disease or trauma. This paper will review emerging periodontal therapies in the areas of materials science, growth factor biology and cell/gene therapy. Several different polymer delivery systems that aid in the targeting of proteins, genes and cells to periodontal and peri-implant defects will be highlighted. Results from preclinical and clinical trials will be reviewed using the topical application of bone morphogenetic proteins (BMP-2 and BMP-7) and platelet-derived growth factor-BB (PDGF) for periodontal and peri-implant regeneration. The paper concludes with recent research on the use of ex vivo and in vivo gene delivery strategies via gene therapy vectors encoding growth promoting and inhibiting molecules (PDGF, BMP, noggin and others) to regenerate periodontal structures including bone, periodontal ligament and cementum.

[The hemolytic site of the basic phospholipase A(2) from Agkistrodon halys pallas]

The gene of the basic phospholipase A(2) from Agkistrodon halys Pallas (BPLA(2) )was mutated site-directedly by polymerase chain reaction (PCR) and the residue Arg(34) of the encloding protein was substituted by Glu and Gln respectively. The mutant gene has been cloned into the expression vector pBLMVL2 and has been expressed in E.coli RR1 effectively. The protein was produced as insoluble inclusion bodies. After partial purification, the inclusion bodies were denatured and renatured into active form, and the renatured recombinant protein was purified by gel-filtration. The expression product has the same enzymatic activity as the denatured-refolded BPLA(2) and its hemolytic activity dropped distinctly, which suggest that the basic residue Arg(34) of BPLA(2) is a crucial amino acid residue during the process of hemolysis.

Role of the Hrp pilus in type III protein secretion in Pseudomonas syringae

Bacterial surface appendages called pili and needle-like filaments are associated with protein and/or DNA transfer to recipient plant, human, or bacterial cells during pathogenesis or conjugation. Although it has long been suspected that pili function as a conduit for protein or DNA transfer, direct evidence has been lacking. The Hrp pilus of Pseudomonas syringae is assembled by the type III secretion system. We used an in situ immunogold labeling procedure to visualize the extrusion of an effector protein, AvrPto, from the tip of the Hrp pilus, providing direct evidence that a bacterial pilus can function as a conduit for protein delivery.

Catalytic asymmetric allylic C-H activation as a surrogate of the asymmetric Claisen rearrangement

[reaction: see text]. Tetrakis[N-[4-dodecylphenyl)sulfonyl]-(S)-prolinato]-dirhodium [Rh2(S-DOSP)4] catalyzed decomposition of methyl aryldiazoacetates in the presence of alkenes results in allylic C-H activation by means of a rhodium-carbene induced C-H insertion. The resulting gamma,delta-unsaturated esters are equivalent to products that would be traditionally obtained from an asymmetric Claisen rearrangement. Highly regio- and enantioselective C-H insertions can be achieved, and in certain cases, good diastereocontrol is also possible.

[Early postoperative complications of choledochal cyst excision and reconstruction of biliary tract]

OBJECTIVE

To study the early postoperative complications of choledochal cyst excision with reconstruction of the biliary tract.

METHODS

In last 10 years, 173 patients aged from 27 days to 14 years (mean = 2.4 years) were operated on with procedures of choledochal cyst excision and biliary tract reconstruction by jejunointerposition between the liver hilum and duodenum or Roux-en-Y hepaticojejunostomy in our hospital. Amongst these 173 patients, 16 were found to suffer from postoperative complications. Therefore, their clinical data were retrospectively analyzed, and the prevention and treatment of the early postoperative complications discussed.

RESULTS

The morbidity of early postoperative complications was 9.3% (16/173). The early complications included biliary leakage in 10 patients, wound dehiscence of abdominal wall in 3, hepatic failure in 1, pancreatic fistula in 1, and postoperative enteric intussusception in 1. The morbidity of early postoperative complications in infants younger than 1-year old was significantly higher than that in children(chi 2 = 15.78, P < 0.01). However, there was no significant difference in the morbidity of early postoperative complications between patients undergoing biliary tract reconstruction by jejunal segment interposition and those undergoing that by Roux-en-Y hepaticojejunostomy (chi 2 = 0.07, P > 0.05). The total mortality in all the operated patients was 2.3% (4/173). Three patients died from biliary leakage and 1 from postoperative hepatic failure.

CONCLUSIONS

Biliary leakage, wound dehiscence of abdominal wall and hepatic failure are major early postoperative complications. The morbidity in infants younger than 1-year old is higher than in children. The preoperative treatment of biliary tract infection, hypohepatia, and surgical skills during operation should be emphasized. Reoperation for biliary leakage should not be delayed and mycotic cholangitis after biliary leakage needs more attention. Tension suture in the fascial space of the abdominal wall is useful for the prevention and treatment of abdominal wall dehiscence.

Use of monozygotic twins in search for breast cancer susceptibility loci

We have used Swedish monozygotic twins concordant for breast cancer to study genetic changes associated with the development of breast cancer. Because loss of heterozygosity (LOH) at a specific genomic region may reflect the presence of a tumour suppressor gene, loss of the same allele in both of the twins concordant for breast cancer may pinpoint a tumour suppressor gene that confers a strong predisposition to breast cancer. DNA samples extracted from the matched tumour and normal tissues of nine twin pairs were analysed for allelic imbalance using a set of microsatellite markers on chromosomes 1, 13, 16 and 17, containing loci with known tumour suppressor genes. The two main regions, where more twin pairs than expected had lost the same allele, were located at 16qtel', including markers D16S393, D16S305 and D16S413, and at 17p13, distal to the p53 locus. Our results show that the monozygotic twin model can be used to suggest candidate regions of potential tumour suppressor genes, even with a limited number of twin pairs.

A simple flow-injection on-line clean-up system for microwave plasma-torch atomic emission spectrometry

A simple flow injection (FI) on-line clean-up system has been developed for microwave plasma-torch atomic emission spectrometry (MPT-AES). A non-selective strongly acidic cation-exchange resin was used to achieve the goal of "on-line clean-up". Ag and Zr, which form halogen-complex anions in halide acid media, and Cr, Mo, and P, which exist as acid group anions or acids (neutral) in acidic solution, were determined and the interfering matrix cations were removed on-line. Satisfactory analytical results were obtained from some practical samples by use of this procedure.

Visualization of secreted Hrp and Avr proteins along the Hrp pilus during type III secretion in Erwinia amylovora and Pseudomonas syringae

Pili are required for protein and/or DNA transfer from bacteria to recipient plant or bacterial cells, based on genetic evidence. However, it has never been shown directly that the effector proteins or DNA are localized along or inside the pili in situ. Failure to visualize an association of effector proteins/DNA with pili is the central issue in the debate regarding the exact function of pili in protein and DNA transfer. In this study, a newly developed in situ immunogold labelling procedure enabled visualization of the specific localization of type III effector proteins of Erwinia amylovora and Pseudomonas syringae pv. tomato along the Hrp pilus, but not along the flagellum or randomly in the intercellular space. In contrast, PelE, a pectate lyase secreted via the type II protein secretion system, was not associated with the Hrp pilus. These results provide direct evidence that type III secretion occurs only at the site of Hrp pilus assembly and that the Hrp pilus guides the transfer of effector proteins outside the bacterial cell, favouring the 'conduit/guiding filament' model.

Geometry of carriers controlling phenotypic expression in BMP-induced osteogenesis and chondrogenesis

BACKGROUND

The effect of the geometry of extracellular matrices on bone morphogenetic protein (BMP)-induced osteogenesis has not been systematically studied. Geometry is crucially important for the scaffold in bone and joint tissue engineering. The purpose of this study was to elucidate principles of geometry of matrices in designing new scaffolds and matrices for use in reconstruction of bone and joints.

METHODS

More than ten biomaterials with different geometries, including a unique device of honeycomb-shaped hydroxyapatite, were combined with BMPs of recombinant (rhBMP-2) or natural bovine origin (S300 BMP cocktail) and implanted subcutaneously into 4-week-old Wistar-King rats. The implanted pellets were removed at 1-4 weeks and analyzed for bone and cartilage formation by histological and biochemical methods.

RESULTS

BMP-induced bone and cartilage induction was highly dependent on the geometric properties of the carrier. Some carriers such as porous particles or blocks of hydroxyapatite induced osteogenesis directly, without detectable chondrogenesis, whereas other carriers such as fibrous glass membrane induced cartilage exclusively. Still other carriers induced mostly cartilage followed by bone formation. Solid particles of hydroxyapatite and fibrous glass membrane with too tight a meshwork did not induce bone or cartilage. The optimal pore size for bone-forming efficacy in porous blocks of hydroxyapatite was a diameter of 300-400 microm. In straight tunnel structures with various diameters in honeycomb-shaped hydroxyapatite, tunnels with smaller diameters (90-120 microm) induced cartilage followed by bone formation, whereas those with larger diameters (350 microm) induced bone formation directly within the tunnels.

CONCLUSIONS

BMP carriers were classified into three types: bone-inducing, cartilage-inducing, and cartilage-bone-inducing. From the analysis of causative factors inducing osteogenesis and chondrogenesis in the BMP system, we concluded that the geometry of the carrier is crucially important and vasculature-inducing geometry should be considered in designing effective scaffolds for bone formation. We propose a classification of geometry of the artificial extracellular matrices that is useful for designing a scaffold for tissue engineering of bone and related tissues.

CLINICAL RELEVANCE

Conventional requisites of the BMP carriers for clinical use have mainly concerned the affinities of carriers with cells and biomolecules and their mechanical strength. The vasculature-inducing geometry of carriers adds a new criterion in designing systems for effective bone and joint reconstruction. The geometries of porous structures-their sizes, continuity, and straightness as verified by hydroxyapatite in this study-will be applicable for other biomaterials for clinical reconstruction therapy.