The Use of Lasers in Disinfection and Cleanliness of Root Canals: a Review

The outcome of root canal treatment is based on efficient disinfection of the root canal system and prevention of reinfection. Current chemomechanical cleaning methods do not always achieve these goals, and insufficient root canal disinfection is the main reason for endodontic failure. Due to high energy content and specific characteristics of laser light, laser treatment has been proposed for cleaning and disinfecting the root canal system. This paper reviews the literature covering the effect of Er:YAG, Er,Cr:YSGG, Nd:YAG and diode laser on the root canal wall in the removal of smear layer and against intracanal bacteria. Recently, the use of laser energy to induce cavitation and acoustic streaming of intracanal irrigants has been investigated. Based on recent literature, it can be concluded that lasers have bactericidal effects. However, they still cannot replace sodium hypochlorite and should be considered as an adjunct to the current chemical root canal disinfection protocols. Certain lasers can help in removing the smear layer and debris and can modify the morphology of the root canal wall. Unfortunately, there have not been enough randomized clinical studies evaluating endodontic treatment outcome following the use of laser.Key words: Disinfection, Root Calan Preparation; Laser Therapy, Low-Level; Smear Layer     

A missense mutation in the 3-ketodihydrosphingosine reductase FVT1 as candidate causal mutation for bovine spinal muscular atrophy

The bovine form of the autosomal recessive neurodegenerative disease spinal muscular atrophy (SMA) shows striking similarity to the human form of the disease. It has, however, been mapped to a genomic region not harboring the bovine orthologue of the SMN gene, mutation of which causes human SMA. After refinement of the mapping results we analyzed positional and functional candidate genes. One of three candidate genes, FVT1, encoding 3-ketodihydrosphingosine reductase, which catalyzes a crucial step in the glycosphingolipid metabolism, showed a G-to-A missense mutation that changes Ala-175 to Thr. The identified mutation is limited to SMA-affected animals and carriers and always appears in context of the founder haplotype. The Ala variant found in healthy animals showed the expected 3-ketodihydrosphingosine reductase activity in an in vitro enzyme assay. Importantly, the Thr variant found in SMA animals showed no detectable activity. Surprisingly, in an in vivo assay the mutated gene complements the growth defect of a homologous yeast knockout strain as well as the healthy variant. This finding explains the viability of affected newborn calves and the later neuron-specific onset of the disease, which might be due to the high sensitivity of these neurons to changes in housekeeping functions. Taken together, the described mutation in FVT1 is a strong candidate for causality of SMA in cattle. This result provides an animal model for understanding the underlying mechanisms of the development of SMA and will allow efficient selection against the disease in cattle.     

Galectin-3 deficiency enhances type 2 immune cell-mediated myocarditis in mice

Experimental autoimmune myocarditis (EAM) is a mouse model of immune-mediated myocarditis and cardiomyopathy. The role of Galectin-3 (Gal-3), a β-galactoside-binding lectin, in autoimmune myocarditis has not been studied. Therefore, the aim of this study was to delineate the role of Gal-3 in myosin peptide-induced autoimmune myocarditis in mice. EAM was induced in relatively resistant C57BL/6J mice (wild type, WT) and in mice with a targeted deletion of Gal-3 gene (Gal-3KO) by immunization with myosin peptide MyHCα_334–352. Gal-3KO mice developed more severe myocarditis and more pronounced heart hypertrophy than WT mice. Increased infiltration of CD45⁺ leucocytes, CD3⁺ T cells, F4/80⁺ macrophages, and eosinophils was observed in hearts of Gal-3KO mice compared to WT mice on day 21 after EAM induction. Moreover, hearts of Gal-3KO mice had more T helper type 2 (Th2) cells, alternatively activated M2 macrophages, higher amounts of IgG deposits, and higher serum levels of IL-4 and IL-33 than WT mice. Ablation of Gal-3 in Th1-dominant C57BL/6J mice that are relatively resistant to EAM resulted in more severe disease characterized by type 2 cardiac inflammation. The complex effects of Gal-3 on EAM progression might be important in the consideration of therapeutic options for the treatment of EAM.     

Transient structural MRI patterns correlate with the motor functions in preterm infants

AimTo explore the relationships between transient structural brain patterns on MRI at preterm and at term-equivalent age (TEA) as a predictor of general movements (GMs) and motor development at 1-year corrected age (CA) in very preterm infants.MethodsIn this prospective study, 30 very preterm infants (median = 28wks; 16 males) had structural magnetic resonance imaging (MRI) at preterm (median = 31wks + 6d) and at TEA (median = 40wks) and neuromotor assessments. The quality of GMs was assessed by Prechtl’s general movements assessment and a detailed analysis of the motor repertoire was performed by calculating a motor optimality score (MOS), both at term age and at 3 months post-term. Motor development at 1-year CA was evaluated with the Infant Motor Profile (IMP). Associations between qualitative MRI findings and neuromotor scores were investigated.ResultsAbnormal GMs and low motor performance at 1-year CA were associated with the poor visibility of transient structural pattern, that is with sagittal strata.InterpretationTransient structural MRI pattern, sagittal strata, at preterm age is related to the quality of GMs and later motor development in preterm infants. This transient fetal brain compartment may be considered as a component of neurobiological basis for early neuromotor behavior, as expressed by GMs.