In vitro fracture resistance of endodontically-treated maxillary premolars

Many endodontically-treated teeth require quick, simple, low-cost restorations. This study evaluated the effect of horizontal pins and flowable composites on the fracture resistance of endodontically-treated maxillary premolars directly restored with resin composite. In this in vitro study, 64 intact human maxillary premolars, extracted for orthodontic reasons, were randomly divided into four groups of 16. Standard access cavities were prepared in such a way that the buccal cusp had a buccolingual thickness of 3 mm measured at the height of contour. The palatal cusp was reduced to 1.5 mm coronal to CEJ. The specimens were prepared as follows: Group 1: resin composite restoration without horizontal self-threading pins or flowable composite (control group). Group 2: resin composite restoration without horizontal self-threading pins but with a 2 mm thickness of the flowable composite. Group 3: resin composite restoration with two horizontal self-threading pins in the buccal cusp but without flowable composite. Group 4: resin composite restoration with two horizontal self-threading pins in the buccal cusp and flowable composite with a thickness of 2 mm. Subsequent to thermocycling, all specimens were loaded to failure. The data were analyzed using a two-factor ANOVA test (alpha = 0.05). The maximum mean of fracture resistance was in Group 1 (632.86 +/- 119.46 N), and the minimum value was related to Group 3 (533.49 +/- 168.07 N). There was not a statistically significant difference between the groups (p > 0.05). Conclusion: Neither horizontal pin placement nor flowable composite had a significant effect on increasing the fracture resistance of endodontically-treated maxillary premolars restored with composite.     

Pharmacokinetics and pharmacodynamics of SB-240563, a humanized monoclonal antibody directed to human interleukin-5, in monkeys

The pharmacokinetics (PK) of SB-240563 have been investigated after i.v. and s.c. administration to cynomolgus monkeys. Approximately linear PK was observed following i.v. administration over a 6000-fold dose range (0.05-300 mg/kg). After i.v. dosing, SB-240563 concentration declined in a biexponential manner with a mean terminal half-life of 13 +/- 2 days. The plasma clearance and volume of distribution at steady state were approximately 0.2 ml/h/kg and 70 ml/kg, respectively. Following s.c. administration, SB-240563 was completely absorbed into the systemic circulation. Because interleukin-5 is known to stimulate production, activation, and maturation of eosinophils, eosinophil counts were measured to assess pharmacologic activity of SB-240563. The maximal response (81-96% decrease in eosinophil count relative to baseline) following a single s.c. administration occurred at 3 weeks postdosing. Suppression of eosinophil count also was observed following multiple monthly administrations of SB-240563 to monkeys. The pharmacokinetic/pharmacodynamic relationship was generally well described with an indirect pharmacologic response model with an estimated IC(50) value of 1.43 microg/ml. The combination of a low IC(50) value for reduction of circulating eosinophils and a long terminal half-life suggests the possibility of an infrequent dosing regimen for SB-240563 for treatment of diseases associated with increased eosinophil function such as asthma.     

Pharmacokinetics of palifermin administered as the standard dose and as a collapsed dose in patients with hematologic malignancies

STUDY OBJECTIVE: To assess the pharmacokinetic profile of palifermin after intravenous dosing with either a collapsed dose of 180 microg/kg/day for 1 day or a standard dose of 60 microg/kg/day for 3 days, before and after myeloablative chemoradiotherapy and peripheral blood progenitor cell (PBPC) transplantation. DESIGN: Prospective, open-label pharmacokinetic study. SETTING: University-affiliated hematology and oncology center. PATIENTS: Twenty-five adult patients with hematologic malignancies receiving myeloablative therapy; 13 were in the standard-dose group, and 12 were in the collapsed-dose group. INTERVENTION: Patients received total-body irradiation (study days -8 to -5), etoposide (day -4), cyclophosphamide (day -2), and PBPC transplantation (day 0). Standard-dose palifermin was administered on days -11, -10, -9, 0, 1, and 2; collapsed-dose palifermin was administered on days -11 and 0. MEASUREMENTS AND MAIN RESULTS: Baseline demographic and clinical characteristics were recorded. Blood samples were obtained for pharmacokinetic assessment, presence of palifermin antibodies, and routine chemistry and hematology panels. Adverse events were documented daily. For both dosing groups, palifermin concentrations declined rapidly (>or= 98%) in the first 30 minutes and increased slightly between 1 and 4 hours after dosing, with a terminal decay phase. For standard-dose palifermin, mean values for area under the serum concentration-time curve (AUC) were within 15% between doses 1 and 3 and within 1% between doses 1 and 4. For collapsed-dose palifermin, mean AUC values and other pharmacokinetic parameters were within 2% between doses 1 and 2. Mean AUC on days -11 and 0 were approximately 4-fold higher for collapseddose palifermin than for standard-dose palifermin. Both dosing regimens were well tolerated. CONCLUSIONS: Our results were consistent with approximately dose-linear pharmacokinetics for the two dosing regimens, with no observed accumulation. A randomized, controlled study is warranted to assess the safety and efficacy of collapsed-dose palifermin, which may provide a more convenient administration schedule.     

Effect of acid and laser etching on shear bond strength of conventional and resin-modified glass-ionomer cements to composite resin

Success in sandwich technique procedures can be achieved through an acceptable bond between the materials. The aim of this study was to compare the effect of 35% phosphoric acid and Er,Cr:YSGG laser on shear bond strength of conventional glass-ionomer cement (GIC) and resin-modified glass-ionomer cement (RMGIC) to composite resin in sandwich technique. Sixty-six specimens were prepared from each type of glass-ionomer cements and divided into three treatment groups as follows: without pretreatment, acid etching by 35% phosphoric acid for 15 s, and 1-W Er,Cr:YSGG laser treatment for 15 s with a 600-μm-diameter tip aligned perpendicular to the target area at a distance of 1 mm from the surface. Energy density of laser irradiation was 17.7 J/cm². Two specimens in each group were prepared for evaluation under a scanning electron microscope (SEM) after surface treatment and the remainder underwent bonding procedure with a bonding agent and composite resin. Then the shear bond strength was measured at a crosshead speed of 0.5 mm/min. Two-factor analysis of variance and post-hoc Tukey test showed that the cement type, surface treatment method, and the interaction of these two factors significantly affect the shear bond strength between glass-ionomer cements and composite resin (p < 0.05). Surface treatment with phosphoric acid or Er,Cr:YSGG laser increased the shear bond strength of GIC to composite resin; however, in RMGIC only laser etching resulted in significantly higher bond strength. These findings were supported by SEM results. The fracture mode was evaluated under a stereomicroscope at ×20.     

Prenatal and perinatal factors associated with developing multiple sclerosis later in life: A systematic review and meta-analysis

ObjectiveBoth genetic and environmental factors play roles in Multiple Sclerosis (MS) etiopathogenesis. The relationship between prenatal/perinatal factors/exposures and future MS occurrence in the offspring remains controversial. Here, we aimed to review the available evidence on prenatal/perinatal factors associated with later MS occurrence.MethodWe performed systematic search of PubMed, Web of Science, and Scopus from inception to October 2020. We included original observational studies conducted on human participants addressing the association between prenatal/perinatal factors and MS occurrence. Data were extracted according to the PRISMA guideline. The adjusted odds ratio (OR) with 95% confidence interval (CI) was considered as the desired effect size. The heterogeneity was evaluated by Cochran's Q and I² and the publication bias was assessed. We excluded gestational/neonatal vitamin D level, season of birth, and latitude because of recently published systematic reviews/meta-analyses on these subjects.ResultsOverall, 2306 records were identified in the primary search. After excluding irrelevant studies, we evaluated 34 studies with contributing data on 100 prenatal/perinatal factors associated with an increased or decreased risk of MS occurrence. In the meta-analyses, we found no statistically significant associations between later MS occurrence in offspring and prenatal smoking exposure (OR = 1.01, 95% CI = 0.77–1.34), mode of delivery (OR = 0.90, 95% CI = 0.52–1.56), birth order (OR = 0.85, 95% CI = 0.72–1.00), and maternal age (OR = 1.34, 95% CI = 0.88–2.04). Paternal age and parents' marital status at the time of childbirth, maternal preeclampsia/ toxemia, forceps use, birth weight, plurality, and preterm birth were the other most studied factors, and none reported to affect MS risk.ConclusionWe found that prenatal smoking exposure, mode of delivery, birth order, and maternal age do not affect risk of future MS development. Moreover, most of the other investigated factors were reported not to affect MS risk in the offspring.     

A 10-Year Cardiovascular Risk in Adults with Different Levels of Spiritual Health: Tehran Lipid and Glucose Study

Background:Previous studies have shown that spiritual experience may reduce cardiovascular disease (CVDs). However, little is known about the relationship between spiritual health and the gender-specific risk of CVDs in communities with different cultures.Methods:A total of 3249 individuals (53.7% female, 75.0% middle-aged) participated in the Tehran Lipid and Glucose Study (TLGS) from 2015 to 2017 were included. Based on the ACC/AHA pooled cohort equation, CVD risk over ten years was examined. Spiritual health was measured using a developed tool for measuring spiritual health in Muslim populations (SHIMA-48). Linear regression models were used to assess the association between spiritual health and ACC/AHA risk scores. The natural logarithm scale was calculated to consider the normal distribution hypothesis of the regression model.Results:The current results suggest a slight but significant increase in the mean of spiritual health in women compared to men in both cognitive/emotional and behavioral dimensions (P < 0.001). In both sexes, a higher prevalence of smoking was observed in participants with lower levels of spiritual health (P < 0.004). In men, compared to those with a low level of spiritual health (the first tertile), the logarithm of the ACC-AHA risk score was reduced by 0.11 (P = 0.004) and 0.18 (P < 0.001) for those in the second and third tertiles of spiritual health, respectively. This result may be attributed to higher cigarette smoking among the latter group. Similar results were not observed in women.Conclusions:Current results indicate a gender-specific association between spiritual health and cardiovascular disease risk. Our findings imply that promoting spiritual health can be considered an effective strategy in future preventive interventions, primarily by controlling the desire to smoke in men.     

Flow Preconditioning of Endothelial Cells on Collagen‐Immobilized Silicone Fibers Enhances Cell Retention and Antithrombotic Function

Stability and antithrombotic functionality of endothelial cells on silicone hollow fibers (SiHFs) are critical in the development of biohybrid artificial lungs. Here we aimed to enhance endothelial cell retention and anti‐thrombotic function by low (12 dyn/cm², 24 h) fluid shear stress (“flow”) preconditioning of endothelial cells seeded on collagen‐immobilized SiHFs. The response of endothelial cells without preconditioning (48 h static culture) and with preconditioning (24 h static culture followed by 24 h flow preconditioning) on hollow fibers to high fluid shear stress (30 dyn/cm², 1 h) was assessed in a parallel‐plate flow chamber. Finite element (FE) modeling was used to simulate shear stress within the flow chamber. We found that collagen immobilization on hollow fibers using carbodiimide bonds provided sufficient stability to high shear stress. Flow preconditioning for 24 h before treatment with high shear stress for 1 h on collagen‐immobilized hollow fibers increased cell retention (1.3‐fold). The FE model showed that cell flattening due to flow preconditioning reduced maximum shear stress on cells by 32%. Flow preconditioning prior to exposure to high fluid shear stress enhanced the production of nitric oxide (1.3‐fold) and prostaglandin I₂ (1.2‐fold). In conclusion, flow preconditioning of endothelial cells on collagen‐immobilized SiHFs enhanced cell retention and antithrombotic function, which could significantly improve current biohybrid artificial lungs.