Coronavirus Disease 2019 (COVID-19): Emerging and Future Challenges for Dental and Oral Medicine

The epidemic of coronavirus disease 2019 (COVID-19), originating in Wuhan, China, has become a major public health challenge for not only China but also countries around the world. The World Health Organization announced that the outbreaks of the novel coronavirus have constituted a public health emergency of international concern. As of February 26, 2020, COVID-19 has been recognized in 34 countries, with a total of 80,239 laboratory-confirmed cases and 2,700 deaths. Infection control measures are necessary to prevent the virus from further spreading and to help control the epidemic situation. Due to the characteristics of dental settings, the risk of cross infection can be high between patients and dental practitioners. For dental practices and hospitals in areas that are (potentially) affected with COVID-19, strict and effective infection control protocols are urgently needed. This article, based on our experience and relevant guidelines and research, introduces essential knowledge about COVID-19 and nosocomial infection in dental settings and provides recommended management protocols for dental practitioners and students in (potentially) affected areas.

Expression of two csg operons is required for production of fibronectin- and congo red-binding curli polymers in Escherichia coli K-12

Two divergently transcribed operons in Escherichia coli required for the expression of fibronectin- and Congo red-binding curli polymers were identified and characterized by transposon mutagenesis, sequencing and transcriptional analyses, as well as for their ability to produce the curli subunit protein. The csgBA operon encodes CsgA, the major subunit protein of the fibre, and CsgB, a protein with sequence homology to CsgA. A non-polar csgB mutant is unaffected in its production of CsgA, but the subunit protein is not assembled into insoluble fibre polymers. A third open reading frame, orfC, positioned downstream of csgA may affect some functional property of curli since an insertion in this putative gene abolishes the autoagglutinating ability typical of curliated cells without affecting the production of the fibre. The promoter for the oppositely transcribed csgDEFG operon was identified by primer extension and shown, like the csgBA promoter, to be dependent upon the alternate stationary phase-specific sigma factor sigma s in wild-type cells, but not in mutants lacking the nucleoid associated protein H-NS. Insertions in csgD abolish completely trancription from the csgBA promoter. Therefore, any regulatory effect on the csgBA promoter might be secondary to events controlling the csgDEFG promoter and/or activation of CsgD. Insertions in csgE, csgF and csgG abolish curli formation but allow CsgA expression suggesting that one or more of these gene products are involved in secretion/assembly of the CsgA subunit protein. No amino acid sequence homologies were found between the CsgE, CsgF and CsgG proteins and secretion/assembly proteins for other known bacterial fibres, suggesting that the formation of curli follows a novel pathway.

Curli fibers are highly conserved between Salmonella typhimurium and Escherichia coli with respect to operon structure and regulation

Mouse-virulent Salmonella typhimurium strains SR-11 and ATCC 14028-1s express curli fibers, thin aggregative fibers, at ambient temperature on plates as judged by Western blot analysis and electron microscopy. Concomitantly with curli expression, cells develop a rough and dry colony morphology and bind the dye Congo red (called the rdar morphotype). Cloning and characterization of the two divergently transcribed operons required for curli biogenesis, csgBA(C) and csgDEFG, from S. typhimurium SR-11 revealed the same gene order and flanking genes as in Escherichia coli. The divergence of the curli region between S. typhimurium and E. coli at the nucleotide level is above average (22.4%). However, a high level of conservation at the protein level, which ranged from 86% amino acid homology for the fiber subunit CsgA to 99% homology for the lipoprotein CsgG, implies functional constraints on the gene products. Consequently, S. typhimurium genes on low-copy-number plasmids were able to complement respective E. coli mutants, although not always to wild-type levels. rpoS and ompR are required for transcriptional activation of (at least) the csgD promoter. The high degree of conservation at the protein level and the identical regulation patterns in E. coli and S. typhimurium suggest similar roles of curli fibers in the same ecological niche in the two species.

Nucleator-dependent intercellular assembly of adhesive curli organelles in Escherichia coli

Bacterial adhesion to other bacteria, to eukaryotic cells, and to extracellular matrix proteins is frequently mediated by cell surface-associated polymers (fimbriae) consisting of one or more subunit proteins. We have found that polymerization of curlin to fimbriae-like structures (curli) on the surface of Escherichia coli markedly differs from the prevailing model for fimbrial assembly in that it occurs extracellularly through a self-assembly process depending on a specific nucleator protein. The cell surface-bound nucleator primes the polymerization of curlin secreted by the nucleator-presenting cell or by adjacent cells. The addition of monomers to the growing filament seems to be driven by mass action and guided only by the diffusion gradient between the source of secreted monomer and the surface of monomer condensation.

Interleukin-17 exacerbates hepatic steatosis and inflammation in non-alcoholic fatty liver disease

Mechanisms associated with the progression of simple steatosis to non-alcoholic fatty liver disease (NAFLD) remain undefined. Regulatory T cells (T(regs)) play a critical role in regulating inflammatory processes in non-alcoholic steatohepatitis (NASH) and because T helper type 17 (Th17) functionally oppose T(reg)-mediated responses, this study focused on characterizing the role of Th17 cells using a NAFLD mouse model. C57BL/6 mice were fed either a normal diet (ND) or high fat (HF) diet for 8 weeks. Mice in the HF group had a significantly higher frequency of liver Th17 cells compared to ND-fed mice. Neutralization of interleukin (IL)-17 in HF mice ameliorated lipopolysaccharide (LPS)-induced liver injury reflected by decreased serum alanine aminotransferase (ALT) levels and reduced inflammatory cell infiltrates in the liver. In vitro, HepG2 cells cultured in the presence of free fatty acids (FFA; oleic acid and palmitic acid) for 24 h and IL-17 developed steatosis via insulin-signalling pathway interference. IL-17 and FFAs synergized to induce IL-6 production by HepG2 cells and murine primary hepatocytes which, in combination with transforming growth factor (TGF-β), expanded Th17 cells. It is likely that a similar process occurs in NASH patients, as there were significant levels of IL-17(+) cell infiltrates in NASH patient livers. The hepatic expression of Th17 cell-related genes [retinoid-related orphan receptor gamma (ROR)γt, IL-17, IL-21 and IL-23] was also increased significantly in NASH patients compared to healthy controls. Th17 cells and IL-17 were associated with hepatic steatosis and proinflammatory response in NAFLD and facilitated the transition from simple steatosis to steatohepatitis. Strategies designed to alter the balance between Th17 cells and T(regs) should be explored as a means of preventing progression to NASH and advanced liver diseases in NAFLD patients.

Expression of two csg operons is required for production of fibronectin- and congo red-binding curli polymers in Escherichia coli K-12

Two divergently transcribed operons in Escherichia coli required for the expression of fibronectin- and Congo red-binding curli polymers were identified and characterized by transposon mutagenesis, sequencing and transcriptional analyses, as well as for their ability to produce the curli subunit protein. The csgBA operon encodes CsgA, the major subunit protein of the fibre, and CsgB, a protein with sequence homology to CsgA. A non-polar csgB mutant is unaffected in its production of CsgA, but the subunit protein is not assembled into insoluble fibre polymers. A third open reading frame, orfC, positioned downstream of csgA may affect some functional property of curli since an insertion in this putative gene abolishes the autoagglutinating ability typical of curliated cells without affecting the production of the fibre. The promoter for the oppositely transcribed csgDEFG operon was identified by primer extension and shown, like the csgBA promoter, to be dependent upon the alternate stationary phase-specific sigma factor sigma s in wild-type cells, but not in mutants lacking the nucleoid associated protein H-NS. Insertions in csgD abolish completely trancription from the csgBA promoter. Therefore, any regulatory effect on the csgBA promoter might be secondary to events controlling the csgDEFG promoter and/or activation of CsgD. Insertions in csgE, csgF and csgG abolish curli formation but allow CsgA expression suggesting that one or more of these gene products are involved in secretion/assembly of the CsgA subunit protein. No amino acid sequence homologies were found between the CsgE, CsgF and CsgG proteins and secretion/assembly proteins for other known bacterial fibres, suggesting that the formation of curli follows a novel pathway.

Expression of and cytokine activation by Escherichia coli curli fibers in human sepsis

Curli organelles are expressed by commensal Escherichia coli K12 and by Salmonella typhimurium at temperatures <37 degrees C, which bind serum proteins and activate the contact-phase system in vitro. This study demonstrates, by means of an anti-CsgA (curli major subunit) antibody, that a significant fraction of E. coli isolates (24 of 46) from human blood cultures produce curli at 37 degrees C in vitro. Serum samples from 12 convalescent patients with sepsis, but not serum from healthy controls, contained antibodies against CsgA (n=12). This study further demonstrates that a curli-expressing E. coli strain and a noncurliated mutant secreting soluble CsgA induce significantly (P<.05) higher levels of proinflammatory cytokines (tumor necrosis factor-alpha, interleukin [IL]-6, and IL-8) in human macrophages differentiated from THP-1 cells. These data, therefore, provide direct evidence that curli are expressed in vivo in human sepsis and suggest a possible role for curli and CsgA in the induction of proinflammatory cytokines during E. coli sepsis.

Colonic immune cells in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND & AIMS

Increases in mucosal immune cells have frequently been observed in irritable bowel syndrome (IBS) patients. However, this finding is not completely consistent between studies, possibly due to a combination of methodological variability, population differences and small sample sizes. We performed a meta-analysis of case-control studies that compared immune cell counts in colonic biopsies of IBS patients and controls.

METHODS

PubMed and Embase were searched in February 2017. Results were pooled using standardized mean difference (SMD) and were considered significant when zero was not within the 95% confidence interval (CI). Heterogeneity was assessed based on I² statistics where I²  ≤ 50% and I²  > 50% indicated fixed and random effect models, respectively.

KEY RESULTS

Twenty-two studies on 706 IBS patients and 401 controls were included. Mast cells were increased in the rectosigmoid (SMD: 0.38 [95% CI: 0.06-0.71]; P = .02) and descending colon (SMD: 1.69 [95% CI: 0.65-2.73]; P = .001) of IBS patients. Increased mast cells were observed in both constipation (IBS-C) and diarrhea predominant IBS (IBS-D). CD3⁺ T cells were increased in the rectosigmoid (SMD: 0.53 [95% CI: 0.21-0.85]; P = .001) and the descending colon of the IBS patients (SMD: 0.79, 95% CI [0.28-1.30]; P = .002). This was possibly in relation to higher CD4⁺ T cells in IBS (SMD: 0.33 [95% CI: 0.01-0.65]; P = .04) as there were no differences in CD8⁺ T cells.

CONCLUSIONS & INFERENCES

Mast cells and CD3⁺ T cells are increased in colonic biopsies of patients with IBS vs non-inflamed controls. These changes are segmental and sometimes IBS-subtype dependent. The diagnostic value of the quantification of colonic mucosal cells in IBS requires further investigation.

Biological mechanisms in palatogenesis and cleft palate

Clefts of the palate are common birth defects requiring extensive treatment. They appear to be caused by multiple genetic and environmental factors during palatogenesis. This may result in local changes in growth factors, extracellular matrix (ECM), and cell adhesion molecules. Several clefting factors have been implicated by studies in mouse models, while some of these have also been confirmed by genetic screening in humans. Here, we discuss several knockout mouse models to examine the role of specific genes in cleft formation. The cleft is ultimately caused by interference with shelf elevation, attachment, or fusion. Shelf elevation is brought about by mesenchymal proliferation and changes in the ECM induced by growth factors such as TGF-betas. Crucial ECM molecules are collagens, proteoglycans, and glycosaminoglycans. Shelf attachment depends on specific differentiation of the epithelium involving TGF-beta3, sonic hedgehog, and WNT signaling, and correct expression of epithelial adhesion molecules such as E-cadherin. The final fusion requires epithelial apoptosis and epithelium-to-mesenchyme transformation regulated by TGF-beta and WNT proteins. Other factors may interact with these signaling pathways and contribute to clefting. Normalization of the biological mechanisms regulating palatogenesis in susceptible fetuses is expected to contribute to cleft prevention.

Defects in ProTaper S1 instruments after clinical use: fractographic examination

AIM

To investigate the mode of failure of a brand of nickel-titanium instruments separated during clinical use, by detailed examination of the fracture surface.

METHODOLOGY

A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into 'torsional' or 'flexural'. The specimens were then re-mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high-power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t-test.

RESULTS

Twenty-seven separated instruments were available for analysis. Under low-power magnification, only two fell into the category of 'torsional' failure when examined laterally; the others appeared to be 'flexural'. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative 'torsional' failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3+/-1.9 mm) was significantly greater than that for shear failure (2.5+/-0.8 mm) (P<0.001, two-sample t-test).

CONCLUSIONS

Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use.

Synthetic peptides entrapped in microparticles can elicit cytotoxic T cell activity

Peptides from Plasmodium berghei circumsporozoite protein (CS) and influenza A virus nucleoprotein (NP) were entrapped in microparticles prepared from poly (lactide-co-glycolide) polymers, and the microparticles were administered parenterally to mice. After immunization with single or multiple doses, splenocytes were tested for a cytotoxic T cell (CTL) response and high levels of CTL activity were detected. The CTL induced were CD8+, MHC class I restricted, and could recognize virus infected cells. Peptide entrapped in microparticles of mean size < 500 nm were better inducers of CTL than larger microparticles (mean > 2 microns and above). Microparticles could also be used to deliver lipid modified peptides (lipopeptides) and elicited higher levels of cytolytic activity than either free peptide in microparticles or lipopeptide alone. Microparticles provide a novel way of inducing a CTL response using synthetic peptides.

Differentiation ability of rat postnatal dental pulp cells in vitro

The current rapid progression in stem cell research has enhanced our knowledge of dental tissue regeneration. In this study, rat dental pulp cells were isolated and their differentiation ability was evaluated. First, dental pulp cells were obtained from maxillary incisors of male Wistar rats. Immunochemistry by stem cell marker STRO-1 proved the existence of stem cells or progenitors in the isolated cell population. The dissociated cells were then cultured both on smooth surfaces and on three-dimensional (3-D) scaffold materials in medium supplemented with beta-glycerophosphate, dexamethasone, and L-ascorbic acid. Cultures were analyzed by light and scanning electron microscopy and, on proliferation, alkaline phosphatase activity and calcium content were determined and the polymerase chain reaction was performed for dentin sialophosphoprotein, osteocalcin, and collagen type I. These cells showed the ability to differentiate into odontoblast-like cells and produced calcified nodules, which had components similar to dentin. In addition, we found that the "odontogenic" properties of the isolated cells were supported by three-dimensional calcium phosphate and titanium scaffolds equally well.

Nucleator function of CsgB for the assembly of adhesive surface organelles in Escherichia coli

Curli are surface organelles in Escherichia coli that assemble outside the bacterium through the precipitation of secreted soluble CsgA monomers, requiring the CsgB nucleator protein. Using immunoelectron microscopy and immunoblotting assays, CsgB is shown to be located on the bacterial surface and also as a minor component of wild-type curli. CsgB lacking its 20 N-terminal residues when fused to maltose-binding protein (MBP) can still trigger polymerization of CsgA monomers in vivo. However, the resulting surface organelles are only formed at one of the two bacterial poles and are morphologically distinct from wild-type curli. These Bfco organelles (CsgB-Free Curli-related Organelles) are highly regular structures reacting with anti-CsgA, but not anti-CsgB antibodies. The CsgB of the active MBP-CsgBII fusion is surface exposed but, unlike the native CsgB in wild-type curli, is not detectable in the Bfco organelles. Overexpression of csgB within a csgA mutant results in the formation of short CsgB polymers on the cell surface. It is suggested that in wild-type bacteria, both CsgA and CsgB are secreted proteins. Interaction between CsgA and CsgB triggers wild-type curli formation, resulting in CsgA-CsgB heteropolymers, while surface-anchored CsgB in MBP-CsgBII triggers morphologically distinct, CsgB-free/CsgA Bfco organelles. In the absence of CsgA, CsgB can self-assemble into polymers.

The Gene Network Underlying Hypodontia

Mammalian tooth development is a precise and complicated procedure. Several signaling pathways, such as nuclear factor (NF)-κB and WNT, are key regulators of tooth development. Any disturbance of these signaling pathways can potentially affect or block normal tooth development, and presently, there are more than 150 syndromes and 80 genes known to be related to tooth agenesis. Clarifying the interaction and crosstalk among these genes will provide important information regarding the mechanisms underlying missing teeth. In the current review, we summarize recently published findings on genes related to isolated and syndromic tooth agenesis; most of these genes function as positive regulators of cell proliferation or negative regulators of cell differentiation and apoptosis. Furthermore, we explore the corresponding networks involving these genes in addition to their implications for the clinical management of tooth agenesis. We conclude that this requires further study to improve patients' quality of life in the future.

Ni-phyllosilicate structure derived Ni–SiO2–MgO catalysts for bi-reforming applications: acidity, basicity and thermal stability

In this work, Ni–SiO₂–MgO materials synthesized via Ni-phyllosilicate (PS) intermediates were explored for bi-reforming of methane (BRM) reaction.

Expression of thin aggregative fimbriae promotes interaction of Salmonella typhimurium SR-11 with mouse small intestinal epithelial cells

The factors that mediate binding of Salmonella typhimurium to small intestinal epithelial cells have not been fully characterized. In this paper we demonstrate that elimination of production of thin aggregative fiber by a transposon insertion within the gene encoding the subunit protein of the fiber reduced binding of S. typhimurium SR-11 to a conditionally immortalized proximal small intestinal epithelial cell line established from transgenic mice. This binding defect could be overcome by transcomplementation with a wild-type allele. The conditionally immortalized cell line should prove useful in identifying the epithelial cell receptor for bacterial attachment since expression of its bacterial binding activity can be induced by manipulating the line's proliferative status.

Mineralized Tissue Formation by BMP2-transfected Pulp Stem Cells

Previously, in vitro differentiation of odontoblasts was shown for dental pulp stem cells (DPSCs) transfected with bone morphogenetic protein-2 ( Bmp2). For this study, we hypothesized that such cells also show potential for mineralized tissue formation in vivo. DPSCs were transfected with Bmp2 and seeded onto a ceramic scaffold. These complexes were cultured in medium without dexamethasone, and thereafter placed subcutaneously in nude mice for 1, 4, and 12 weeks. Samples were evaluated by histology and real-time PCR for osteocalcin, bone sialoprotein, dentin sialophosphoprotein, and dentin matrix protein 1. Results indicated that only the transfected DPSCs showed obvious mineralized tissue generation, and 12 weeks of implantation gave the highest percentage of mineralized tissue formation (33 ± 7.3% of implant pore area). Real-time PCR confirmed these results. In conclusion, Bmp2-transfected DPSCs effectively show mineralized tissue formation upon ectopic implantation.

Activation of inducible nitric oxide synthase/nitric oxide by curli fibers leads to a fall in blood pressure during systemic Escherichia coli infection in mice

Septic shock, a major cause of death, is characterized by a pathophysiologic increased production of nitric oxide (NO), which leads to vasodilation and myocardial toxicity. Septic Escherichia coli frequently express proteinaceous curli fibers. In this study, curliated E. coli induced high levels of NO by directly inducing type 2 nitric oxide synthase (NOS2) both in vitro and in vivo. More severe hypotension and higher plasma nitrite/nitrate levels were seen in wild type mice systemically infected with curliated E. coli than in animals infected with E. coli mutants that lacked curli proteins. Blood pressure remained stable in NOS2-deficient mice with curliated bacteria. Increased heart rates, transient hypothermia, and loss of gross activity were seen in all mice, regardless of curli expression. Study results suggest that expression of curli fibers by E. coli activates the NO/NOS2 arm of the innate immune system, which leads to a significant fall in blood pressure.

Patterns and correlates of major depression in Chinese adults: a cross-sectional study of 0.5 million men and women

BACKGROUND

Worldwide 350 million people suffer from major depression, with the majority of cases occurring in low- and middle-income countries. We examined the patterns, correlates and care-seeking behaviour of adults suffering from major depressive episode (MDE) in China.

METHOD

A nationwide study recruited 512 891 adults aged 30-79 years from 10 provinces across China during 2004-2008. The 12-month prevalence of MDE was assessed by the Modified Composite International Diagnostic Interview-short form. Logistic regression yielded adjusted odds ratios (ORs) of MDE associated with socio-economic, lifestyle and health-related factors and major stressful life events.

RESULTS

Overall, 0.7% of participants had MDE and a further 2.4% had major depressive symptoms. Stressful life events were strongly associated with MDE [adjusted OR 14.7, 95% confidence interval (CI) 13.7-15.7], with a dose-response relationship with the number of such events experienced. Family conflict had the highest OR for MDE (18.9, 95% CI 16.8-21.2) among the 10 stressful life events. The risk of MDE was also positively associated with rural residency (OR 1.5, 95% CI 1.4-1.7), low income (OR 2.3, 95% CI 2.1-2.4), living alone (OR 2.6, 95% CI 2.3-3.0), smoking (OR 1.4, 95% CI 1.3-1.6) and certain other mental disorders (e.g. anxiety, phobia). Similar, albeit weaker, associations were observed with depressive symptoms. Among those with MDE, about 15% sought medical help or took psychiatric medication, 15% reported having suicidal ideation and 6% reported attempting suicide.

CONCLUSIONS

Among Chinese adults, the patterns and correlates of MDE were generally consistent with those observed in the West. The low rates of seeking professional help and treatment highlight the great gap in mental health services in China.

The risk predictive values of UK-PBC and GLOBE scoring system in Chinese patients with primary biliary cholangitis: the additional effect of anti-gp210

BACKGROUND

Adequate risk stratification is critical for the management of the patients with primary biliary cholangitis (PBC). The UK-PBC and GLOBE scoring systems for prognosis of PBC have been proposed recently, but have not been validated in Asian population.

AIM

To validate the UK-PBC and GLOBE scoring systems in Chinese patients for prognosis of PBC. To clarify the role of anti-gp210 as a biomarker, and to investigate whether anti-gp210 could affect the prognostic values of UK-PBC and GLOBE scoring systems.

METHODS

We retrospectively analysed 276 patients with PBC evaluated between September 2004 and May 2016, including 133 anti-gp210+ and 143 anti-gp210- patients.

RESULTS

The 5-year adverse outcome-free survivals of anti-gp210+ vs. anti-gp210- patients were 70% and 85%, respectively (P = 0.005). Cirrhosis (P = 0.001), albumin level ≤40 g/L (P = 0.011) and platelet count ≤153 × 10⁹ (P < 0.001) had a superimposition effect on anti-gp210 antibody as a risk factor. Furthermore, long-term prognoses were evaluated using the UK-PBC and GLOBE scores. For UK-PBC scoring system, the area under receiver operating characteristic curve (AUROC) was 0.924 for all patients with PBC (n = 223), 0.940 for anti-gp210+ patients (n = 110) and 0.888 for anti-gp210- patients (n = 113). For GLOBE scoring system, the area under receiver operating characteristic curve was 0.901 for all patients with PBC (n = 223), 0.924 for anti-gp210+ patients (n = 110) and 0.848 for anti-gp210- patients (n = 113). UK-PBC score >0.0578 (P < 0.001, HR: 32.736, 95% CI: 11.368-94.267) and GLOBE score <0.850 (P < 0.001, HR: 18.763, 95% CI: 7.968-44.180) were associated with poorer outcomes in the whole cohort.

CONCLUSIONS

The UK-PBC and GLOBE scoring systems were good 5-year prognostic predictors in Chinese patients with PBC, especially in anti-gp210+ patients. As a biomarker, anti-gp210 antibody was associated with a more severe cholestatic manifestation and a worse long-term prognosis. The anti-gp210 antibody could be added to further optimise the UK-PBC and GLOBE scoring systems.

The comparative study of Sprague-Dawley and Lewis rats in adjuvant-induced arthritis

The outbred Sprague-Dawley (SD) rats, similar to the inbred Lewis (LEW) rats, have been recently demonstrated to be highly susceptible to adjuvant-induced arthritis (AIA). We herein compared AIA in SD and LEW rats in terms of clinical, histological, radiological, and immuno-inflammatory features. The results showed that, following inoculation with a ground Mycobacterium tuberculosis (MT) suspension, SD and LEW rats manifested closely similar disease progression, with 100% incidence and similar severity. The development of arthritis was accompanied by significantly higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels than in control rats. Radiographic examination of the hind paws showed that both SD and LEW AIA rats manifested conspicuous soft tissue swelling, bone matrix resorption, periosteal new bone formation and bone erosion, while histopathological analysis of the synovial joints revealed marked cellular infiltration, angiogenesis, synovial hyperplasia, pannus formation, narrowing of joint space, and cartilage and bone destruction. Moreover, in relation to disease progression, serum tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 levels were markedly overexpressed in both SD and LEW AIA versus control rats, and SD and LEW AIA rats exhibited divergent profiles for the expression of TNF-alpha and IL-1beta. Taken together, these results demonstrated that the SD rat AIA model shares several arthritic features with the comparable model in LEW rats. Hence, given the more favorable characteristics of SD rats than LEW rats (i.e., lower cost, wider availability, and heterogenic background), this SD rat AIA model is more cost effective and advantageous for screening and testing novel anti-arthritic agents.

Associations of blood glucose and prevalent diabetes with risk of cardiovascular disease in 500 000 adult Chinese: the China Kadoorie Biobank

AIMS

To examine the relationship of self-reported diabetes, and of random blood glucose levels among individuals without known diabetes, with the prevalence of cardiovascular disease in Chinese adults.

METHODS

We examined cross-sectional data from the China Kadoorie Biobank of 0.5 million people aged 30-79 years recruited from 10 diverse regions of China in the period 2004-2008. Logistic regression was used to estimate the odds ratios of prevalent cardiovascular disease associated with self-reported diabetes, and with measured random blood glucose levels among participants with no history of diabetes, adjusting simultaneously for age, sex, area, education, smoking, alcohol, blood pressure and physical activity.

RESULTS

A total of 3.2% of participants had self-reported diabetes (men 2.9%; women 3.3%) and 2.8% had screen-detected diabetes (men 2.6%; women 2.8%), i.e. they had no self-reported history of diabetes but a blood glucose level suggestive of a diagnosis of diabetes. Compared with individuals without a history of diabetes, the odds ratios associated with self-reported diabetes were 2.18 (95% CI 2.06-2.30) and 1.88 (95% CI 1.75-2.01) for prevalent ischaemic heart disease and stroke/transient ischaemic attack, respectively. Among participants without self-reported diabetes there was a positive association between random blood glucose and ischaemic heart disease and stroke/transient ischaemic attack prevalence (P for trend <0.0001). Below the diabetic threshold (<11.1 mmol/l) each additional 1 mmol/l of random blood glucose was associated with 4% (95% CI 2-5%) and 5% (95% CI 3-7%) higher odds of prevalent ischaemic heart disease and stroke/transient ischaemic attack, respectively.

CONCLUSIONS

In this adult Chinese population, self-reported diabetes was associated with a doubling of the odds of prevalent cardiovascular disease. Below the threshold for diabetes there was still a modest, positive association between random blood glucose and prevalent cardiovascular disease.

A novel locus for autosomal dominant hereditary gingival fibromatosis, GINGF3, maps to chromosome 2p22.3-p23.3

Hereditary gingival fibromatosis (HGF) is a rare, benign disorder characterized by slowly progressive fibrous overgrowth of the gingiva. To date, two loci have been mapped in familial cases with autosomal dominant non-syndromic HGF: GINGF (MIM 135300) on chromosome 2p21-p22 and GINGF2 (MIM 605544) on chromosome 5q13-q22. Of the two loci, only SOS1 (son of sevenless one, MIM 182530) gene underlying GINGF locus has been identified. Ascertainment of a large Chinese family has allowed the mapping of a novel locus to 2p22.3-p23.3, GINGF3. Haplotype construction and analysis localized the new locus to an 11.4-cM interval between markers D2S2221 (telomeric) and D2S1788 (centromeric). The maximum two-point limit of detection (LOD) score of 3.45 (theta=0) and multipoint LOD score of 5.00 for marker D2S390 strongly supported linkage to this region. Thus, this genetic interval is distal to and does not overlap with the previously described locus, GINGF, on 2p21-p22.