Effect of Fluoride Prophylactic Agents on the Surface Topography of NiTi and CuNiTi Wires

Aim: The aim of this study was to see the effect of topical fluoride on surface texture on nickel-titanium and copper-nickel-titanium orthodontic archwires. Materials and methods: Preformed rectangular NiTi and CuNiTi wires were immersed in in fluoride solution and artificial saliva (control) for 90 minutes at 37°C. after immersion optical microscope was used to see the fluoride effect on the wire topography. Results: The acidulated fluoride agents appeared to cause greater corrosive effects as compared to the neutral fluoride agents. Conclusion: The result suggest that using topical fluoride agents leads to corrosion of surface topography indirectly affecting the mechanical properties of the wire that will lead to prolonged orthodontic treatment. Clinical significance: The use of topical fluoride agents has to be limited in patients with prolonged orthodontic treatment as it causes the corrosion of the NiTi and CuNiTi wires. Keywords: NiTi, CuNiTi, Fluoride agents, Optical microscope. How to cite this article: Mane PN, Pawar R, Ganiger C, Phaphe S. Effect of Fluoride Prophylactic Agents on the Surface Topography of NiTi and CuNiTi wires. J Contemp Dent Pract 2012;13(3):285-288. Source of support: Nil Conflict of interest: None declared.     

von Willebrand factor (VWF) propeptide binding to VWF D'D3 domain attenuates platelet activation and adhesion

Noncovalent association between the von Willebrand factor (VWF) propeptide (VWFpp) and mature VWF aids N-terminal multimerization and protein compartmentalization in storage granules. This association is currently thought to dissipate after secretion into blood. In the present study, we examined this proposition by quantifying the affinity and kinetics of VWFpp binding to mature VWF using surface plasmon resonance and by developing novel anti-VWF D'D3 mAbs. Our results show that the only binding site for VWFpp in mature VWF is in its D'D3 domain. At pH 6.2 and 10mM Ca(2+), conditions mimicking intracellular compartments, VWFpp-VWF binding occurs with high affinity (K(D) = 0.2nM, k(off) = 8 × 10(-5) s(-1)). Significant, albeit weaker, binding (K(D) = 25nM, k(off) = 4 × 10(-3) s(-1)) occurs under physiologic conditions of pH 7.4 and 2.5mM Ca(2+). This interaction was also observed in human plasma (K(D) = 50nM). The addition of recombinant VWFpp in both flow-chamber-based platelet adhesion assays and viscometer-based shear-induced platelet aggregation and activation studies reduced platelet adhesion and activation partially. Anti-D'D3 mAb DD3.1, which blocks VWFpp binding to VWF-D'D3, also abrogated platelet adhesion, as shown by shear-induced platelet aggregation and activation studies. Our data demonstrate that VWFpp binding to mature VWF occurs in the circulation, which can regulate the hemostatic potential of VWF by reducing VWF binding to platelet GpIbα.     

The computing platelet: integrating environmental cues

In this issue of Blood, Flamm et al combine high-throughput experimental methods and multiscale computer simulations to predict patient-specific thrombus formation potential.(1) Their studies reveal a novel thromboxane receptor mutation (TP-V241G) in humans that confers resistance to indomethacin.     

Regio- and diastereoselective synthesis of spiropyrroloquinoxaline grafted indole heterocyclic hybrids and evaluation of their anti-Mycobacterium tuberculosis activity

An efficient and eco compatible approach for the regio- and stereoselective synthesis of structurally diverse novel hybrid heterocycles comprising spiropyrrolidine, indenoquinoxaline and indole structural units in excellent yields, has been achieved through a one-pot multicomponent process involving 1,3-dipolar cycloaddition as a key step. The 1,3-dipolar component is the azomethine ylide generated in situ from indenoquinoxaline and l-tryptophan and reacts with various substituted β-nitrostyrenes affording the spiroheterocyclic hybrids. The ring system thus created possesses two C–C and three C–N bonds and four adjacent stereogenic carbons, one of which is quaternary and the reaction proceeded with full diastereomeric control. All the synthesized compounds were assayed for their in vitro activity against Mycobacterium tuberculosis H37Rv using MABA assay. Interestingly, the compound bearing a 2-fluoro substituent on the aryl ring displayed an equipotent activity (MIC 1.56 μg mL⁻¹) to ethambutol against Mycobacterium tuberculosis H37Rv.

An efficient and eco compatible approach for the regio- and stereoselective synthesis of structurally diverse novel spiropyrrolidine tethered indole hybrids in excellent yields employing a one-pot multicomponent 1,3-dipolar cycloaddition strategy.     

Complementary alternative medicine practices and beliefs in spinal cord injury and non-spinal cord injured individuals

Context/Objective: To compare the beliefs and practices of individuals with spinal cord injury (SCI), their friends and family members (F&F SCI), and healthcare professionals (HCP) regarding complementary alternative medicine (CAM).

Design: A questionnaire regarding CAM practices and beliefs was administered to participants on paper or online.

Setting: An academic rehabilitation hospital.

Participants: Ninety-six individuals voluntarily participated in the study. Participants included 28 patients with SCI, 36 F&F SCI, and 32 HCP.

Interventions: Not applicable

Outcome Measures: The questionnaire assessed participants’ prior or current use of 14 CAM modalities, their willingness to use CAM in the future or recommend its use, and their beliefs and opinions of CAM.

Results: Participants with SCI and their family and friends, were more likely than HCP to have used CAM (P?≤?0.01 and P?≤?0.03, respectively) and recommend its use (P?≤?0.04 and P?≤?0.03, respectively). All three groups showed statistical significance in their willingness to ever use certain CAM modalities (P?≤?0.03 for SCI, P?≤?0.04 for F&F SCI, and P?≤?0.02 for HCP). SCI, F&F SCI, and HCP groups had similar beliefs and opinions regarding CAM.

Conclusion: Patients with SCI as well as their friends and family, have significantly more experience with CAM and are more likely to recommend its use than HCP, suggesting that they are interested and find benefit in alternative healthcare. This warrants further investigation of the integration of CAM into general health practices for those with SCI.     

Circulating microparticle tissue factor,thromboembolism and survival in pancreaticobiliary cancers

Background

Tissue factor (TF), the physiologic initiator of coagulation, is over-expressed in pancreatic cancer, and is associated with a pro-coagulant and pro-angiogenic state. We hypothesized that in patients with pancreaticobiliary cancers (PBC), elevated circulating microparticle-associated TF (MP-TF) activity would be associated with thrombosis and worsened survival.

Patients and Methods

Clinical data and plasma were obtained for consecutive patients with PBC seen at Roswell Park Cancer Institute from 2005-08. MP-TF activity levels were measured using a TF-dependent FXa generation assay.

Results

The study population comprised 117 patients, including pancreatic (n = 80), biliary (n = 34) or unknown primary histologically consistent with PBC (n = 3). Of these, 52 patients (44.5%) experienced thromboembolism, including pulmonary embolism (n = 15), deep venous thrombosis (n = 21) and other arterial or venous events (n = 32). Mean TF was 2.15 (range 0.17- 31.01) pg/mL. Median survival was 98.5 days for MP-TF activity ≥ 2.5 pg/mL versus 231 days for MP-TF activity < 2.5 pg/mL (p < 0.0001). In multivariate analysis, elevated MP-TF activity was associated with both VTE (OR 1.4, 95% CI 1.1-1.6) and mortality (HR 2.5, 95% CI 1.4-4.5).

Conclusions

Elevated circulating MP-TF activity is associated with thrombosis and worsened survival in patients with PBC. MP-TF activity as a prognostic biomarker warrants further prospective evaluation.     

Effect of hyperglycemia on reperfusion-associated recovery of intracellular pH and high energy phosphates after transient cerebral ischemia in gerbils

Abstract

Hyperglycemia increases cerebral damage after transient cerebral ischemia. This study used in vivo 31P nuclear magnetic resonance spectroscopy to determine the relationship of intracellular tissue acidosis and delayed recovery of brain high-energy phosphates to increased damage during the reperfusion period. Mongolian gerbils were subjected to transient bilateral carotid ischemia for 20 min with 2 h reperfusion. All gerbils were pretreated intraperitoneally with equivalent volumes in saline of 0.003 units per kilogram of insulin or vehicle, or with 4 grams of glucose per kilogram. The gerbils were then scanned in a 4.7 Tesla Magnetic Resonance Imager-Spectrometer to determine levels of intracellular pH, inorganic phosphate, adenosine triphosphate, and phosphocreatine. In each group, intracellular pH decreased with ischemia, but most significantly in hyperglycemic animals (6.45±0.15), in which it had not recovered to pre- ischemic levels by the end of the reperfusion period (6.8 ±0.1 vs 7.04 ±0.1, p <0.05). High-energy phosphates phosphocreatine-inorganic phosphate and phosphocreatine-adenosine triphosphate showed partial recovery in all groups throughout the reperfusion period; the recovery was not significantly altered by glucose status. Hyperglycemia worsened pH but not the recovery of high-energy phosphates in animals reperfused after 20 min of transient cerebral ischemia. This sustained acidosis may be a primary event in transient damage in hyperglycemic animals. [Neurol Res 1996; 18: 546-552]     

The Maintenance of Wakefulness Test in Pediatric Narcolepsy

Objective tools are needed to assess the response to treatment in pediatric narcolepsy. This article presents a single-center experience documenting the use of the maintenance of wakefulness test (MWT) in a pediatric series. This study reviewed the charts of children with narcolepsy who had an MWT performed between January 2008 and June 2012. A cutoff was used for mean sleep latency: <8 minutes for inadequate control of hypersomnia, and >20 minutes to indicate adequate control on medications. Thirteen tests were performed on 10 children (median age 15.8 years, range 8.7-20.3 years) with narcolepsy, of which six had cataplexy and three were boys. Comorbid conditions included Prader-Willi syndrome, bipolar affective disorder, and epilepsy (n = 1 each). The median mean sleep latency for all studies was 16 minutes (range 5.8-40 minutes). Sleep-onset rapid eye movement sleep events were seen in three of 13 studies. In seven patients, findings from the MWT resulted in changes in management. These data suggest that the MWT may be a useful and feasible test for assessing response to treatment in children with narcolepsy. Future research is needed to obtain normative MWT data on children with and without narcolepsy.     

Pyrazole–coumarin and pyrazole–quinoline chalcones as potential antitubercular agents

Pyrazole, coumarin, and quinoline are medicinally important moieties. In this study, two series of novel pyrazole–coumarin chalcones and pyrazole–quinoline chalcones were synthesized using multiple-step reactions. All the synthesized compounds were well characterized using different spectroscopic techniques including ¹H and ¹³C nuclear magnetic resonance, high-resolution mass spectroscopy, and electrospray ionization–mass spectrometry. The compounds were evaluated for their antitubercular activity against the Mycobacterium tuberculosis H37Rv strain using the microplate Alamar Blue assay, and the minimal inhibitory concentrations (MIC) of the compounds were determined. Among the 32 tested compounds, compounds 3e , 3u , and 7h showed an MIC value of 3.125 µg/ml, and they were found to be nontoxic. Molecular docking studies of the compounds with the enzyme DprE1 revealed the probable mechanism of action. The chalcone derivatives exhibited binding affinity values between −7.047 and −9.353 kcal/mol. ADME parameters were predicted using the QikProp module of the Schrödinger software, and these compounds exhibited good pharmacological and oral absorption properties.