Computational fluid dynamics analysis of salivary flow and its effect on sialolithogenesis

OBJECTIVE

Sialolithiasis is a common disease caused by intraductal stones, formed by reduction in salivary flow, salivary stagnation, and metabolic events. We used computational fluid dynamics to investigate changes in salivary flow field around parotid stones of different shapes.

MATERIALS AND METHODS

Three-dimensional configurations of the Stensen's duct were reconstructed from computed tomography sialographic images. Fluid dynamics modeling was used to analyze the salivary flow field around stones under unstimulated and stimulated conditions.

RESULTS

The majority of sialoliths were oval-shaped (59/98), followed by irregular (24/98) and round (15/98). Salivary velocity was significantly higher around streamlined stones, compared with round (P = 0.013) and oval (P = 0.025) types. Changes in salivary flow field around sialoliths were found to affect the pattern of mineral deposition in saliva. The area of low velocity around the round stone was double the size observed around the streamlined stone during the unstimulated state, whereas in the stimulated state, local vortexes were formed on the downstream side of round and oval stones.

CONCLUSIONS

Salivary flow field around sialoliths plays an important role in the progression of multicentric stones, and analysis of the salivary dynamics during sialolithiasis may provide deeper understandings of the condition and aid in developing successful treatment strategies.

Probing the repulsive core of the nucleon-nucleon interaction via the (4)He(e,e'pN) triple-coincidence reaction

We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830  MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ∼500  MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.

Long-term outcomes after nucleos(t)ide analogue discontinuation in HBeAg-positive chronic hepatitis B patients

Nucleos(t)ide analogue (NUC) resistance is an important clinical risk resulting from long-term therapy in chronic hepatitis B (CHB) management. Discontinuation of NUCs is a feasible strategy to reduce resistance. We aimed to observe the outcomes after NUC withdrawal in HBeAg-positive CHB patients. A total of 97 patients (11 patients with HBsAg loss and 86 patients with sustained HBeAg seroconversion) were enrolled. HBV DNA levels and alanine aminotransferase (ALT) levels were monitored regularly after discontinuation. Relapse was defined as HBV DNA levels >2000 IU/mL in at least two determinations more than 4 weeks apart. HBeAg seroconversion was achieved within 48 weeks (interquartile range (IQR), 24-72 weeks). The time on consolidation therapy was 96 weeks (IQR, 84-144 weeks). No relapses occurred for HBsAg loss patients. Evidence of relapse was observed in 9.3% of HBeAg seroconversion patients. All relapse cases occurred within 48 weeks after discontinuation. The time to relapse was 33 ± 15 weeks. Elevation of HBV DNA and ALT levels over baseline were only observed in 12.5% of relapse patients. There were no significant differences in baseline characteristics (sex, HBV genotype, age or ALT levels) or time on consolidation therapy between patients with relapse or sustained response. NUC discontinuation in HBeAg-positive CHB patients is feasible after achieving HBeAg seroconversion at a minimum of 24 weeks. There is further benefit to prolonging the time on consolidation therapy to reduce relapse. More than 48 weeks of sustained response is a predictive marker for long-term sustained response.

Chinese SLE Treatment and Research group (CSTAR) registry: II. Prevalence and risk factors of pulmonary arterial hypertension in Chinese patients with systemic lupus erythematosus

Objectives

To estimate the prevalence of pulmonary arterial hypertension (PAH) and risk factors for PAH in patients registered in the Chinese SLE Treatment and Research group (CSTAR) database, the first online registry of Chinese patients with systemic lupus erythematosus (SLE).

Methods

A prospective cross-sectional study of patients with SLE was conducted using the CSTAR registry. Resting transthoracic echocardiography was used to estimate pulmonary artery pressure (PAP); PAH was defined as systolic PAP (PASP) ≥40 mmHg. Patients with interstitial lung disease, valvular disease or cardiomyopathy were excluded because of disease influence on PAP. We explored potential risk factors for PAH including patient characteristics, organ involvement, laboratory findings and SLE disease activity.

Results

Of 1934 patients with SLE, 74 had PASP with 54.2 ± 17.1 (40,106) mmHg and were diagnosed with probable PAH. The incidences of lupus nephritis, pleuritis, pericarditis, hypocomplementemia, anti-SSA, and anti-ribonucleoprotein (RNP) were significantly higher in patients with PAH than in those without ( p<0.05). SLE disease activity was significantly higher in patients with PAH than in unaffected patients ( p<0.05). Multivariate analysis indicated that pericarditis (odds ratio (OR) = 4.248), pleuritis (OR = 3.061) and anti-RNP (OR = 2.559) were independent risk factors for PAH in patients with SLE ( p<0.05).

Conclusions

The possible prevalence of PAH was 3.8% in Chinese patients with SLE in the CSTAR registry. The significant association of pericarditis, pleuritis and anti-RNP positivity with PAH suggests that higher disease activity and vasculopathy may both contribute to the development of PAH in SLE, which need be treated aggressively to improve prognosis.

Analysis of antithrombotic therapy in elderly patients with atrial fibrillation

This study aimed to analyze the impact factors and outcome of antithrombotic therapy in elderly patients over 65 years old that suffered from atrial fibrillation (AF). A total of 256 elderly patients with AF over 65 years old were divided into 3 groups: 65-74 years old (N = 86), 75-84 years old (N = 122), and over 85 years old (N = 48). The clinical characteristics, antithrombotic therapy, and its related impact factors were retrospectively analyzed. Of all patients, 187 received antithrombotic therapy. In the 65-74 year-old group, 78 patients received antiplatelet treatment (90.7%) and 5 patients received anticoagulation treatment (5.8%). In the 75-84 year-old group, 76 patients received antiplatelet treatment (62.3%) and 14 patients received anticoagulation treatment (11.5%). In the group of over 85 year-olds, 33 patients received antiplatelet therapy (68.8%) and 4 patients received anticoagulation treatment (8.3%). Eleven patients had deep vein thrombosis and atrial thrombosis during antiplatelet therapy (5.9%), 5 patients had gastrointestinal hemorrhage after antiplatelet therapy (2.7%), 2 patients had gastrointestinal bleeding, and 3 patients had brain hemorrhage after anticoagulation treatment (21.7%). Suboptimal antithrombotic therapy was observed in the elderly patients with AF, partly owing to the risks of both thromboembolism and bleeding.

Involvement of CRH and hCG in the induction of aromatase by cortisol in human placental syncytiotrophoblasts

INTRODUCTION

Increased estrogen production in placenta towards the end of gestation plays a pivotal role in the onset of human labor. Estrogen transforms myometrium from a quiescent to a contractile status. Glucocorticoids have been shown to induce estrogen production through the transcription factor specificity protein 1 (Sp1)-mediated induction of aromatase transcription upon elevation of cyclic adenosine mono-phosphate (cAMP) level in human placental syncytiotrophoblasts. However, it is unclear how glucocorticoids activate cAMP pathway thereby inducing aromatase expression in human placental syncytiotrophoblasts.

MATERIAL AND METHODS

We investigated this issue in cultured primary human placental syncytiotrophoblasts prepared from placentas collected at term without labor.

RESULTS

We demonstrated that cortisol (0.01-1 μM) dose-dependently increased corticotropin-releasing hormone (CRH) and human chorionic gonadotropin (hCG) α/β subunit expression and their production in the syncytiotrophoblasts. The induction of intracellular cAMP level, Sp1 expression, Sp1 enrichment at the aromatase promoter as well as aromatase expression by cortisol could be partially attenuated by either hCG antibody (1:100) or CRH receptor antagonist α-helical-CRH (1 μM), and further attenuated by combination of hCG antibody and α-helical-CRH.

CONCLUSIONS

Cortisol increases aromatase expression via induction of CRH and hCG production and subsequent elevation of cAMP level and enrichment of Sp1 at the aromatase promoter in human placental syncytiotrophoblasts. These findings may account for the parallel increases of cortisol and estrogen production prior to the onset of parturition.

Chinese SLE Treatment and Research group (CSTAR) registry: I. Major clinical characteristics of Chinese patients with systemic lupus erythematosus

The Chinese systemic lupus erythematosus (SLE) treatment and research group (CSTAR) provides major clinical characteristics of SLE in China and establishes a platform to provide resources for future basic and clinical studies. CSTAR originated as a multicentre, consecutive, and prospective design. The data were collected online from 104 rheumatology centers, which covered 30 provinces in China. The registered patients were required to meet four or more of the American College of Rheumatology (ACR) criteria for the classification of SLE. All CSTAR centers use the same protocol-directed methods to provide uniform evaluations, which included demographic data, clinical features, laboratory examinations, and disease activity evaluations. The patient samples, including DNA samples and sera, were also collected for further quality controls and additional studies. Preliminary analysis from 2104 baseline evaluations was available for this analysis. Of 1914 female and 190 male patients (F:M=10.1), the mean age at onset was 29.2 y with confirmed diagnosis one year later at the age of 30.3 y. Eighty four (4.2%) of 2002 patients had a family history of rheumatic diseases, including 34 (1.7%) cases with SLE. In addition, one hundred and seven (5.2%) abnormal pregnancies were recorded among 2026 experiences. The characteristics of the CSTAR cohort were compared to similarly sized cohorts from other studies. We found that 56.1% of patients presented with concurrent hematological disorders compared to only 18.2% of European patients. Moreover, 47.4% of patients presented with nephropathy compared to 27.9% of European patients. Conversely, neurological manifestations were only seen in 4.8% of Chinese SLE patients compared to 19.4% of European patients, 12.1% of U.S. patients, 22.8% of Malaysian patients and 26.4% of Latin Americans. Pulmonary arterial hypertension and interstitial lung diseases were complications identified in 3.8% and 4.2% of Chinese lupus patients, respectively. The CSTAR registry has provided epidemiological data and phenotypes of Chinese patients with SLE, and has demonstrated several differences between ethnicities. Clinical data and biologic samples would be valuable resources for future translational studies with national and international collaboration.

Plasmoid formation in current sheet with finite normal magnetic component

Current sheet configurations in natural and laboratory plasmas are often accompanied by a finite normal magnetic component that is known to stabilize the two-dimensional resistive tearing instability in the high Lundquist number regime. Recent magnetohydrodynamic simulations indicate that the nonlinear development of ballooning instability is able to induce the formation of X lines and plasmoids in a generalized Harris sheet with a finite normal magnetic component in the high Lundquist number regime where the linear two-dimensional resistive tearing mode is stable.

Novel EDA p.Ile260Ser mutation linked to non-syndromic hypodontia

Hypodontia, a tooth developmental disease, can affect chewing and pronunciation. Mutations in the ectodysplasin-A (EDA) gene can lead to both X-linked hypohidrotic ectodermal dysplasia (XLHED) and non-syndromic hypodontia (NSH). However, the mechanism by which these 2 related but different disorders are caused by the distinct mutations in EDA is unknown. In this study, we identified a novel missense mutation (c.779 T>G) in a Chinese family with NSH via a direct sequencing approach. This mutation results in an Ile260Ser substitution in the tumor necrosis factor (TNF) homology domain. Homology modeling suggests that this alteration may induce a conformational change in the hydrophobic center of the TNF homology domain. Furthermore, by exploring systematic 3D conformation analysis and calculation of residue relative solvent accessibility (RSA) for all the reported mutated amino acid sites on EDA's TNF homology domain, we found that the site mutations at the interior may be linked to XLHED, while those at the surface are more likely to be associated with NSH. These findings may aid in the discovery of unidentified functionally significant mutation sites in the EDA gene and provide a new way to clarify the mechanisms by which the XLHED and NSH phenotypes arise from mutations in the same gene.

A new technology for separation and recovery of materials from waste printed circuit boards by dissolving bromine epoxy resins using ionic liquid

Recovery of valuable materials from waste printed circuit boards (WPCBs) is quite difficult because WPCBs is a heterogeneous mixture of polymer materials, glass fibers, and metals. In this study, WPCBs was treated using ionic liquid (1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM+][BF4-]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM+][BF4-] solution containing WPCBs was heated to 240 °C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260 °C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM+][BF4-] was treated by water to generate a solid-liquid suspension, which was separated completely to obtain solid residues by filtration. Thermal analyses combined with infrared ray spectra (IR) observed that the solid residues were bromine epoxy resins. NMR (nuclear magnetic resonance) showed that hydrogen bond played an important role for [EMIM+][BF4-] dissolving bromine epoxy resins. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent environmental pollution from WPCBs effectively.

Treatment of waste printed circuit board by green solvent using ionic liquid

Recycling of waste printed circuit boards (WPCBs) is an important subject not only for the protection of environment but also for the recovery of valuable materials. A feasibility study was conducted to dissolve bromine epoxy resins of WPCBs using ionic liquid (IL) of 1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM(+)][BF(4)(-)] (nonaqueous green solvent) for recovering copper foils and glass fibers. Experimental results indicated that the initial delamination had seen from the cross-section of the WPCBs by mean of metallographic microscope and digital camera when WPCBs were heated in [EMIM(+)][BF(4)(-)] at 240°C for a duration of 30 min. When temperature was increased to 260°C for a duration of 10 min, the bromine epoxy resins of WPCBs were throughout dissolved into [EMIM(+)][BF(4)(-)] and the separations of copper foils and glass fibers from WPCBs were completed. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent the environmental pollution of WPCBs effectively.

Perianal necrotizing fasciitis treated with a loose-seton technique

AIM

The study evaluated the effect of a loose-seton technique for perianal necrotizing fasciitis.

METHOD

The medical records of seven patients with perianal necrotizing fasciitis treated by the loose-seton technique between December 2005 and June 2010 were reviewed. Age, gender, status of diabetes mellitus, duration of symptoms, the length of hospital stay and number of debridements were investigated.

RESULTS

Five of the patients were men. The mean age was 53 years and the range was 43-79 years. All seven patients had a past history of acute perianal abscess. Six (85.7%) patients had diabetes mellitus. The mean time for removal of the seton was 24 (14-32) days and the mean hospitalization time was 31 (23-45) days. All patients had primary wound healing. There was no mortality. At a median follow-up 18 (6-60) months one patient required inpatient treatment with cutting-seton for complex anal fistula after 11 months. All patients had normal faecal continence and none of them required a reconstructive procedure during the follow-up.

CONCLUSION

The loose-seton technique is an effective treatment for perianal necrotizing fasciitis. The advantages include inhibiting the spread of inflammation, reducing the frequency of debridements, decreasing the area of the wound and limiting extensive scar formation.

Synovial fluid dynamics with small disc perforation in temporomandibular joint

The articular disc plays an important role as a stress absorber in joint movement, resulting in stress reduction and redistribution in the temporomandibular joint (TMJ). The flow of synovial fluid in the TMJ may follow a regular pattern during movement of the jaw. We hypothesised that the regular pattern is disrupted when the TMJ disc is perforated. By computed tomography arthrography, we studied the upper TMJ compartment in patients with small disc perforation during jaw opening-closing at positions from 0 to 3 cm. Finite element fluid dynamic modelling was accomplished to analyse the pattern of fluid flow and pressure distribution during the movements. The results showed that the fluid flow in the upper compartment generally formed an anticlockwise circulation but with local vortexes with the jaw opening up to 2 cm. However, when the jaw opening-closing reached 3 cm, an abnormal flow field and the fluid pressure change associated with the perforation may increase the risk of perforation expansion or rupture and is unfavourable for self-repair of the perforated disc.

Measurement of the neutron radius of 208Pb through parity violation in electron scattering

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

Randomized clinical trial comparing infrahepatic inferior vena cava clamping with low central venous pressure in complex liver resections involving the Pringle manoeuvre

BACKGROUND

Control of bleeding remains key to successful hepatic resection. The present randomized clinical trial compared infrahepatic inferior vena cava (IVC) clamping with low central venous pressure (CVP) during complex hepatectomy using portal triad clamping (PTC).

METHODS

Consecutive patients undergoing complex hepatectomy were allocated randomly to PTC combined with infrahepatic IVC clamping or to PTC with low CVP. Primary outcome was blood loss during parenchymal transection. Secondary outcomes were intraoperative surgical and haemodynamic parameters, postoperative recovery of liver and renal function, postoperative morbidity and mortality, and duration of hospital stay.

RESULTS

Between January 2008 and September 2010, 192 patients were randomized. Compared with low CVP, infrahepatic IVC clamping significantly decreased blood loss during parenchymal transection (mean(s.e.m.) 243(158) versus 372(197) ml; P < 0·001), was associated with faster recovery of liver function, and caused less impairment in renal function and fewer haemodynamic changes. The degree of cirrhosis correlated positively with CVP (R(2) = 0·963, P = 0·019) and with infrahepatic IVC pressure (R(2) = 0·950, P = 0·025). For patients with moderate or severe cirrhosis, infrahepatic IVC clamping was more efficacious in controlling blood loss during parenchymal transection (mean(s.e.m.) 2·9(1·8) versus 6·1(2·4) ml/cm(2); P < 0·001).

CONCLUSION

PTC combined with infrahepatic IVC clamping is more efficacious in controlling bleeding during complex hepatectomy than PTC with low CVP, especially in patients with moderate to severe cirrhosis.

REGISTRATION NUMBER

NCT01355887 (http://www.clinicaltrials.gov).