In vitro evaluation of the influence of velocity on sliding resistance of stainless steel arch wires in a self-ligating orthodontic bracket.

INTRODUCTION: Of the variables used by in vitro studies of resistance to sliding (RS) in orthodontics, sliding velocity (SV) of the wire is often the one farthest from its clinical counterpart. We investigated whether velocity influences the RS at values approximating the orthodontic movement. METHODS: A SS self-ligating bracket with a NiTi clip was fixed onto a custom-made model. Different shaped orthodontic SS wires of four sizes and two types (round, 0.020″ and 0.022″; rectangular, 0.016″×0.022″ and 0.017″×0.025″) were tested using an Instron® testing machine. Wires were pulled at four velocities (1×10-2  mm/s, 1×10-3  mm/s, 1×10-4  mm/s, 1×10-5  mm/s). Shapiro-Wilk test was used to evaluate the normal distribution of the data; two-way ANOVA was performed to compare means in the RS with wire characteristics and SV. Significance level was set at P<.05. RESULTS: RS was higher for rectangular wires, and for those with larger diameters. Lower SV was associated with lower RS, with wire type and size having an interaction effect. The RS relatively to SV can be represented as: RS ∝ α[ln(SV)]+ß, where α and ß are constants. CONCLUSIONS: At very low SV and low normal forces, SV influences the RS of SS archwires in orthodontic brackets, and the proportionality is logarithmic. Although respecting these parameters in vitro is challenging, quantitative evaluations of RS should be carried out at clinically relevant velocities if aiming at translational application in the clinical scenario.

Iatrogenic atrial septal defect does not affect acute hemodynamic modifications after transcatheter edge-to-edge repair in patients with functional mitral regurgitation.

OBJECTIVE: The correction of functional mitral regurgitation (FMR) with transcatheter edge-to-edge repair (TEER) can favorably affect patients' hemodynamic profile. However, the procedure requires inter-atrial trans-septal access and the hemodynamic relevance of the residual iatrogenic atrium septal defect (iASD) is still debated. This study aimed at investigating the hemodynamic modifications during TEER with MitraClip, before and after the iASD creation, in patients with heart failure with reduced ejection fraction (HFrEF) and severe FMR. METHODS: Thirty-nine HFrEF patients with 3+ or 4+/4+ FMR were included. Right heart catheterization was performed at baseline after general anesthesia induction and at the end of TEER, both before and after removing the device guiding catheter. RESULTS: Compared with baseline, MitraClip positioning was followed by a significant immediate improvement in cardiac output (respectively: 3.36 vs 5.05 ml/min), pulmonary artery wedge pressure (23.7 vs 18.2 mmHg), mean pulmonary artery pressure (34.4 vs 27.7 mmHg) and pulmonary vascular resistance (3.6 vs 2.2 Wood Units) (all p < 0.001). No further significant modifications occurred after removing the device guiding catheter. CONCLUSIONS: Our data suggest that the acute hemodynamic modifications after TEER are not influenced by the induction of iASD in patients with FMR.

Circulating cytokines and growth factors in professional soccer players: correlation with in vitro-induced motor neuron death.

BACKGROUND: professional soccer players are susceptible to amyotrophic lateral sclerosis. Strenuous physical activity has been associated with persistent inflammatory conditions and elevation of systemic cytokine levels, which could contribute to the vulnerability of these athletes. To investigate changes induced by playing soccer in the systemic profiles of growth factors and of the principal cytokines involved in the inflammatory response, we compared the serum concentrations of these factors in Italian professional soccer players and sedentary subjects. We also investigated the effects of the sera on primary cultured motor neurons in relation to their cytokine and growth factor content. METHODS: serum concentrations of cytokines and growth factors were measured by a biochip array analyzer. Neurotoxicity of sera was assessed by immunocytochemical assays in primary motor neuron cultures from mouse embryos. RESULTS: circulating levels of interleukin-8, tumor necrosis factor-alpha and interleukin-4 were lower in soccer players than controls. However, the viability of primary cultured mouse motor neurons treated with sera from the two groups did not differ significantly. Vascular endothelial growth factor (VEGF) independently emerged as a systemic protective factor for motor neurons. CONCLUSIONS: we found significant alterations in circulating pro-inflammatory cytokines in Italian professional soccer players, showing an unbalanced inflammatory condition in these subjects. VEGF was a protective serum factor affecting motor neuron survival.

Cone beam computed tomography role in diagnosis and treatment of impacted canine patient's: a case report.

A tooth is impacted when its apex is formed but does not erupt as expected during the physiological timeframe of eruption. The frequency with which the upper canine is impacted in the sample examined varies from 1% to 5% of the population in the second decade of life. The most frequent causes of inclusion of the upper canine are: lack of resorption or precocious loss of the root of the deciduous, agenesis of the lateral, an anomaly in its shape, lack of space in the arch, presence of a mechanical obstacle to the eruption, and lastly due to hereditary factors. When dental impaction is suspected, radiographic examination is indicated to evaluate the effect that the impacted element is having in the context of the osseous structure and to evaluate its relationships with adjacent teeth, the presence of mechanical obstacles, the placement of the inclusion and its orientation in space, how well developed the root is, and any anomalies in its shape. In addition to the classic orthopantomography (OPT), endoral radiography, teleradiography, can be used in order to obtain three-dimensional and life-size images, techniques of computed tomography (CT). In particular, cone beam CT, obtains this type of image using a radioactive dose comparable to that obtained summarizing the classic radiographic examinations requested by an orthodontist and moreover less that that administered when using classic multi-layer spiral CT medical equipment. This case report describes the diagnostic iter and orthodontic-surgical treatment of a patient with enclosure of the right upper canine.

HTLV-II/HIV-1 coinfection and risk for progression to AIDS among intravenous drug users.

To determine whether coinfection with HTLV-II influences the course of HIV-1 infection, we evaluated the progression from asymptomatic HIV infection (CDC group II) to persistent generalized lymphadenopathy (CDC group III) to AIDS-related complex (CDC group IVA) to full-blown AIDS (CDC group IVC) to death from AIDS in two groups of HIV-seropositive intravenous drug users (IVDUs). The first group consisted of 123 patients infected with HIV-1 only, and the second comprised 22 patients with serological and molecular evidence of HTLV-II/HIV-1 coinfection. Results of the immunological and clinical follow-up indicated a greater likelihood of developing persistent generalized lymphadenopathy among individuals infected with HIV-1 alone than among those coinfected with HTLV-II. However, no statistical difference was detected between the two groups in the depletion of CD4+ cells, the temporal decrease of the CD4/CD8 ratio, or the progression to ARC or AIDS or to death from AIDS. These findings suggest that HTLV-II may have no effect on the clinical evolution of HIV infection in IVDUs, which may be explained by the lack of pathogenicity of the HTLV-II coinfecting strain(s) and/or other still unclear biological or immunological cofactors or mechanisms.

TIPP[psi], a highly selective delta ligand.

TIPP[psi] is a new delta-selective opioid peptide antagonist. In the current study, we have explored its selectivity against the mu and kappa receptor subtypes. Against [3H]DPDPE binding, TIPP[psi] is quite potent, with a Ki value of < 1 nM, confirming its potent activity at delta receptors. In contrast, its Ki values against mu 1, mu 2, kappa 1, kappa 2 and kappa 3 binding sites are all > 5 microM. DPDPE also is delta-selective. It labels delta sites > 25-fold more potently than mu 1 receptors and is even more selective against the other subtypes. However, this selectivity does not compare to the delta/mu 1 selectivity of TIPP[psi] which exceeds 15,000. This far higher selectivity, coupled with its antagonist properties, gives TIPP[psi] a number of advantages over previously reported delta-selective compounds. We have utilized these advantages to develop an improved mu 1 binding assay using TIPP[psi].

Effects of sodium acetate on rat bone-nodule formation and mineralization in vitro.

Sodium acetate reportedly promotes bone atrophy by inducing resorption and inhibiting osteoprogenitor-cell proliferation, but little is known about its effects on bone-matrix deposition and mineralization by a population containing osteoprogenitor cells. The objective here was to assess the effects of 1-20 mM sodium acetate on the proliferation and differentiation of these cells and their resultant bone-nodule formation and mineralization in an in vitro assay. Exposure to 10 mM sodium acetate had no effect on cellular proliferation but significantly increased the production and mineralization of bone nodules (p < 0.01), suggesting that it affected osteoprogenitor differentiation and subsequent metabolism. However, 10 mM acetate did not increase net bone mass. Dilutions of 1-5 and 20 mM inhibited cellular proliferation and resultant bone-nodule formation and mineralization, significantly reducing the percentage bone area as compared to controls (p < 0.001). These data suggest that 1-5 and 20 mM sodium acetate significantly inhibit bone deposition, whereas 10 mM has no effects, which could contribute to iatrogenic metabolic bone disease in patients receiving either renal dialysis or total parenteral nutrition.

Effect of strain on bone nodule formation by rat osteogenic cells in vitro.

The purpose of this study was to assess in vitro bone nodule formation by cells exposed to a range of microstrain, at a sub-optimal oscillation frequency for bone formation. Fetal rat calvarial cells experienced a Flexercell regimen within either FLEX I (deformable) or FLEX II (non-deformable) substrates. Cells in FLEX I plates were exposed to growth medium only; those in FLEX II plates were exposed to either growth medium only, or growth medium + 10(-7) M IGF-1. Cell numbers were assessed from 1 to 6 days. Other cells were exposed to the Flexercell regimen (-2 kPa, 0.05 Hz) for 1-3 (Group 1), 3-6 (Group 2), 1-9 (Group 3) or 10-15 (Group 4) days and were maintained, at other times, under standard conditions. After 21 days, nodules were counted within each well and within the compression, <999, 1000-4900, 5000-9999, 10,000-14,999 and 15,000-25,000 microstrain regions of the FLEX I membrane. Cyclic deformation inhibited cell numbers from 1 to 6 days, compared to control or IGF-1 groups (P<0.001). The number of nodules in Groups 2 and 4 were greater than Groups 1 or 3 (P<0.001), but not different from control or IGF-1 groups. Compression or tensile microstrain significantly affected nodule formation in all groups, with Group 4 producing more nodules than other groups in most microstrain regions. Thus, the number of bone nodules produced by osteogenic cell cultures exposed to cyclic deformation was significantly affected by the timing of initiation and the characteristics and magnitude of the deformation regimen.

Immunological evaluation in children with juvenile chronic arthritis treated with auranofin.

An immunological evaluation was performed before therapy and every four months during the first year of treatment with auranofin in 6 children with juvenile chronic arthritis. The immunological tests included: IgG, IgA, IgM, IgE and "natural" antibody serum levels, CH50 of the classical and alternative complement pathways, PWM-induced IgM production in vitro, and polymorphonuclear neutrophil functions. A reduction of the in vitro IgM synthesis and in the CH50 of the classical pathway of complement, and a normalization of impaired chemotaxis, occurred in patients who presented a clinically significant improvement during auranofin treatment.

[In vitro study of amalgam corrosion]. / Studio in vitro sulla corrosione di amalgami.

AIMS: In the dental field, the aim of the research was to evaluate, through a standardized system, the factors influencing the corrosion of dental alloys in different clinical conditions with various types of amalgams and/or solution parameters. METHODS: A 6-hole corrosion cell was used according to ASTM G5-95 protocol. RESULTS AND CONCLUSIONS: It is well known that free surface corrosion is uncommon in the oral cavity in the case of most dental alloys. But localized corrosion, either as pitting or as crevice corrosion, might occur. The clinical conditions affecting amalgam corrosion may be detectable in localized corrosion, in particular because of cathodic/anodic surface behaviour coupling.

[Mechanical resistance of endodontically treated upper first premolar crowns]. / Resistenza meccanica della corona dei primi premolari superiori trattati endodonticamente.

This work shows the results of mechanical strength tests effected over first superior bicuspids before endodontically treated. The Authors show the strength differences, in connection to the access-cavity, between endodontically treated and non-treated teeth. Finally it was found that the demolition of only one marginal ridge reduces the tooth strength to withstand the occlusal forces.

Zinc lowers high-density lipoprotein-cholesterol levels.

Zinc administration in rats is associated with a rise in serum cholesterol level. This study examined the effect of zinc administration on serum lipoprotein values in man. Twelve healthy adult men ingested 440 mg of zinc sulfate per day for five weeks. High-density lipoprotein-cholesterol concentration decreased 25% below baseline values (40.5 to 30.1 mg/dL). Total cholesterol, triglyceride, and low-density lipoprotein-cholesterol levels did not change throughout the study. The sharp fall of the "antiatherogenic" lipoprotein, high-density lipoprotein, associated with zinc administration supports the concept that zinc ingestion may be atherogenic in man.

Biochemical and pharmacological characterization of mu, delta and kappa 3 opioid receptors expressed in BE(2)-C neuroblastoma cells.

Total opioid binding in the human neuroblastoma cell line BE(2)-C has a density similar to that found in brain, with a Bmax value of 383 +/- 60 fmol/mg protein and a KD of 0.4 +/- 0.07 nM for the nonselective opioid antagonist 3H-diprenorphine. Selective assays reveal a binding distribution of mu (38%), delta (16%) and kappa 3 (43%) opioid receptors. There is no observable kappa 1 or kappa 2 binding. The sum of the Bmax values in the selective binding assays (370 +/- 39 fmol/mg protein) approximates closely that observed with 3H-diprenorphine, suggesting that mu, delta and kappa 3 sites account for most of the binding. The binding selectivities of various opiates and opioid peptides in the BE(2)-C cells are similar to those in rat brain. Delta and mu binding are defined easily by traditional selective ligands. The binding profiles also distinguish clearly mu from kappa 3 binding. The selective mu ligand DAMGO competes with mu binding over 35-fold more potently than kappa 3 binding, whereas morphine shows a 10-fold selectivity. Functionally, selective mu, delta and kappa 3 agonists inhibit forskolin-stimulated cAMP accumulation through distinct receptor mechanisms that are pertussis toxin-sensitive. In addition to demonstrating that BE(2)-C cells provide a useful model system for studying mu, kappa 3 and delta receptors, these studies confirm that kappa 3 receptors represent a pharmacologically distinct receptor class in this cell line.