Tissue Debris Research Articles

The Role of Microglial Phagocytosis in Ischemic Stroke.

Microglia are the resident immune cells of the central nervous system that exert diverse roles in the pathogenesis of ischemic stroke. During the past decades, microglial polarization and chemotactic properties have been well-studied, whereas less attention has been paid to phagocytic phenotypes of microglia in stroke. Generally, whether phagocytosis mediated by microglia plays a beneficial or detrimental role in stroke remains controversial, which calls for further investigations. Most researchers are in favor of the former proposal currently since efficient clearance of tissue debris promotes tissue reconstruction and neuronal network reorganization in part. Other scholars propose that excessively activated microglia engulf live or stressed neuronal cells, which results in neurological deficits and brain atrophy. Upon ischemia challenge, the microglia infiltrate injured brain tissue and engulf live/dead neurons, myelin debris, apoptotic cell debris, endothelial cells, and leukocytes. Cell phagocytosis is provoked by the exposure of “eat-me” signals or the loss of “don’t eat-me” signals. We supposed that microglial phagocytosis could be initiated by the specific “eat-me” signal and its corresponding receptor on the specific cell type under pathological circumstances. In this review, we will summarize phagocytic characterizations of microglia after stroke and the potential receptors responsible for this programmed biological progress. Understanding these questions precisely may help to develop appropriate phagocytic regulatory molecules, which are promoting self-limiting inflammation without damaging functional cells.

MORPHO-HISTOLOGICAL CHARACTERISTICS OF BRUISES WITH DIFFERENT AGE - QUALITATIVE STUDY

Bruises are common skin lesions that occur as the force hits the skin, but integrity of the skin is not impaired. Their significance is important in forensic expert reports in determining the time of death in many cases of domestic violence or child abuse. The aim of this study was to present the differences between bruises with different time of origin by evaluation of their morpho-histological characteristics.  The study included 60 human skin samples divided into control and experimental groups A, B, C, D. The experimental group A included bruised human skin samples with <1day old bruises, experimental group B included bruised human skin samples with 1-3 days old bruises, experimental group C included bruised human skin samples with 3-7 days old bruises and experimental group D included bruised human skin samples with 7-14 days old bruises. Paraffin sections of the skin were stained with Hematoxylin-eosin, Giemsa, Perl’s Prussian Blue, Masson-Goldner methods of staining and application of anti-HO-1 antibody. All paraffin sections were evaluated by light microscopy and photodocumented. Our results have shown changes in color in bruises with different age due to infiltration with different immune cells and metabolism of extracellular hemoglobin.  Granulocyte infiltration is seen shortly after the initiation of the bruise, while after few days of initiation, usually 1-3, there is macrophage infiltration in the field of bleeding. Presence of macrophages in the field of bleeding increases as bruises age. These histological characteristics appear in direction of healing the bruise, together with phagocytosis of the erythrocytes and removing the tissue debris.  Keywords: bruises, time of origin, morpho-histological characteristics, microscopic analysis 

White matter microglia heterogeneity in the CNS.

Microglia, the resident myeloid cells in the central nervous system (CNS) play critical roles in shaping the brain during development, responding to invading pathogens, and clearing tissue debris or aberrant protein aggregations during ageing and neurodegeneration. The original concept that like macrophages, microglia are either damaging (pro-inflammatory) or regenerative (anti-inflammatory) has been updated to a kaleidoscope view of microglia phenotypes reflecting their wide-ranging roles in maintaining homeostasis in the CNS and, their contribution to CNS diseases, as well as aiding repair. The use of new technologies including single cell/nucleus RNA sequencing has led to the identification of many novel microglia states, allowing for a better understanding of their complexity and distinguishing regional variations in the CNS. This has also revealed differences between species and diseases, and between microglia and other myeloid cells in the CNS. However, most of the data on microglia heterogeneity have been generated on cells isolated from the cortex or whole brain, whereas white matter changes and differences between white and grey matter have been relatively understudied. Considering the importance of microglia in regulating white matter health, we provide a brief update on the current knowledge of microglia heterogeneity in the white matter, how microglia are important for the development of the CNS, and how microglial ageing affects CNS white matter homeostasis. We discuss how microglia are intricately linked to the classical white matter diseases such as multiple sclerosis and genetic white matter diseases, and their putative roles in neurodegenerative diseases in which white matter is also affected. Understanding the wide variety of microglial functions in the white matter may provide the basis for microglial targeted therapies for CNS diseases.

Investigation of the Feasibility of Ventricular Delivery of Resveratrol to the Microelectrode Tissue Interface.

(1) Background: Intracortical microelectrodes (IMEs) are essential to basic brain research and clinical brain–machine interfacing applications. However, the foreign body response to IMEs results in chronic inflammation and an increase in levels of reactive oxygen and nitrogen species (ROS/RNS). The current study builds on our previous work, by testing a new delivery method of a promising antioxidant as a means of extending intracortical microelectrodes performance. While resveratrol has shown efficacy in improving tissue response, chronic delivery has proven difficult because of its low solubility in water and low bioavailability due to extensive first pass metabolism. (2) Methods: Investigation of an intraventricular delivery of resveratrol in rats was performed herein to circumvent bioavailability hurdles of resveratrol delivery to the brain. (3) Results: Intraventricular delivery of resveratrol in rats delivered resveratrol to the electrode interface. However, intraventricular delivery did not have a significant impact on electrophysiological recordings over the six-week study. Histological findings indicated that rats receiving intraventricular delivery of resveratrol had a decrease of oxidative stress, yet other biomarkers of inflammation were found to be not significantly different from control groups. However, investigation of the bioavailability of resveratrol indicated a decrease in resveratrol accumulation in the brain with time coupled with inconsistent drug elution from the cannulas. Further inspection showed that there may be tissue or cellular debris clogging the cannulas, resulting in variable elution, which may have impacted the results of the study. (4) Conclusions: These results indicate that the intraventricular delivery approach described herein needs further optimization, or may not be well suited for this application.

Removal of accumulated hard tissue debris from mesial root of mandibular molars evaluated using micro-CT - a systematic review and network meta-analysis.

Aim The aim of this systematic review and network meta-analysis was to identify the best irrigant activation technique (IAT) for the removal of accumulated hard tissue debris (AHTD) from the mesial root of mandibular molars evaluated using micro-CT studies.Methods The research question was based on the PICO format. Four electronic databases - PubMed, Scopus, Embase and Web of Science - were searched for articles up to June 2020. Selected articles were assessed for bias using the Joanna Briggs Institute Critical appraisal tool. The network meta-analysis using a fixed-effects model and SUCRA ranking were performed. The quality of the evidence was assessed using the CINeMA framework.Results Eleven studies were included for qualitative synthesis while seven were included for quantitative synthesis. The risk of bias of all included articles was low. The results based on SUCRA values revealed the IAT shock wave-enhanced emission photoacoustic streaming (100%) resulted in the greatest reduction of the volume of AHTD from mesial roots of mandibular molars. Ranking of the other IATs was as follows: photon-induced photoacoustic streaming (87%), laser-activated irrigation (79.3%), XP EndoFinisher (71.2%), ultrasonically activated irrigation (59.6%), apical negative pressure (42.3%), EasyClean (37.4%), EDDY (26.2%), EndoActivator (24.2%), self-adjusting file (11.6%) and needle irrigation (11.3%).Conclusion None of the IATs rendered the root canals completely free of AHTD. The laser-activated irrigation groups fared better than all other interventions in reducing AHTD from the mesial roots of mandibular molars. The confidence rating ranged from low to high for indirect evidence and moderate to high for mixed evidence. Results must be interpreted with caution due to the laboratory nature of the included studies.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Accelerate Functional Recovery After Spinal Cord Injury by Promoting the Phagocytosis of Macrophages to Clean Myelin Debris.

Macrophage phagocytosis contributes predominantly to processing central nervous system (CNS) debris and further facilitates neurological function restoration after CNS injury. The aims of this study were to evaluate the effect of bone marrow mesenchymal stem cells (BMSC)-derived exosomes (BMSC-Exos) on the phagocytic capability of macrophages to clear myelin debris and to investigate the underlying molecular mechanism during the spinal cord injury (SCI) process. This work reveals that monocyte-derived macrophages (MDMs) infiltrating into the SCI site could efficiently engulf myelin debris and process phagocytic material. However, the phagocytic ability of macrophages to clear tissue debris is compromised after SCI. The administration of BMSC-Exos as an approach for SCI treatment could rescue macrophage normal function by improving the phagocytic capability of myelin debris internalization, which is beneficial for SCI repair, as evidenced by better axon regrowth and increased hindlimb locomotor functional recovery in a rodent model. Examination of macrophage treatment with BMSC-Exos revealed that BMSC-Exos could promote the capacity of macrophages to phagocytose myelin debris in vitro and could create a regenerative microenvironment for axon regrowth. In addition, we confirmed that BMSC-Exo treatment resulted in improved phagocytosis of engulfed myelin debris by promoting the expression of macrophage receptor with collagenous structure (MARCO) in macrophages. The inhibition of MARCO with PolyG (a MARCO antagonist) impaired the effect of BMSC-Exos on the phagocytic capacity of macrophages and resulted in compromised myelin clearance at the lesion site, leading to further tissue damage and impaired functional healing after SCI. In conclusion, these data indicated that targeting the phagocytic ability of macrophages may have therapeutic potential for the improvement in functional healing after SCI. The administration of BMSC-Exos as a cell-free immune therapy strategy has wide application prospects for SCI treatment.

Differential Expression Pattern of Pathogenicity-Related Genes of Ralstonia pseudosolanacearum YQ Responding to Tissue Debris of Casuarina equisetifolia

Ralstonia solanacearum species complex (RSSC) contains a group of destructive plant pathogenic bacteria, causing bacterial wilt of >200 species of crops and trees, such as Casuarina equisetifolia, worldwide. RSSC can survive in the soil environment for a long time and start infection after activation by host plants. This study conducted a transcriptome analysis on the expression pattern of the pathogenicity-related genes of a new isolated RSSC strain YQ (Ralstonia pseudosolanacearum phylotype I-16) in response to C. equisetifolia cladophyll (a branch of a stem that resembles and functions as a leaf) and root debris under invitro culture. The cladophyll debris induced more genes up-regulated than the root debris, including pathogenicity-related genes involved in motility, effectors, type III secretion systems, quorum sensing, and plant cell wall degradation. Besides, many differentially expressed genes were related to transcriptional regulator such as cyclic dimeric guanosine monophosphate. Moreover, the cultures with cladophyll debris induced a faster wilting in bioassays, and the cell swimming was enhanced by cladophyll exudate. C. equisetifolia cladophylls could activate the expression of pathogenicity-related genes of strain YQ and accelerate infection. Our findings suggest that litterfall management in C. equisetifolia forests, or even other plantations, should receive attention to prevent the induction of bacterial wilt disease caused by RSSC.

Doppler ultrasound observations and metrics of boiling histotripsy treatment progression

Boiling histotripsy (BH) is a mechanical tissue fractionation method that uses millisecond-long nonlinear HIFU pulses with shock fronts. The BH treatment generates bubbles and tissue debris that move within the liquified lesion due to acoustic radiation force and streaming. Since the velocity of the debris is expected to depend on the lesion size and fractionation completeness, it could provide a quantitative metric of the treatment progression. In this study, the motion of bubble remnants and tissue debris immediately following BH pulses was investigated by high-pulse repetition frequency (PRF) plane-wave color Doppler ultrasound (PRF 9–15 kHz, 50–100 pulses) in ex vivo bovine myocardium and porcine liver. A 256-element 1.5 MHz spiral HIFU array with a coaxially integrated ultrasound imaging probe (ATL P4-2) produced the 10ms BH pulses to create a volumetric lesion in tissue. As tissue liquefaction progressed, the velocity was observed to be directed towards the HIFU transducer, monotonically increased, and then saturated at about 1 m/s. Further, when the lesion was fully liquefied and its axial size was comparable to that of the HIFU focal spot, the motion changed direction to the opposite, with velocity independent of tissue type, consistent with streaming. [Work supported by NIH R01EB7643, R01GM122859, R01EB025187, and RSF20-12-00145.]

Efficacy of Sonic Versus Ultrasonic Irrigation in Debris Removal from the Root Canal System: A Systematic Review

Introduction: The aim of this study was to systematically review the debridement efficacy of ultrasonic irrigation compared with sonic irrigation during the endodontic treatment. Methods: An electronic search was undertaken on Cochrane Library, Medline, ScienceDirect and Scopus for articles published between January 2010 and January 2021 using appropriate Mesh terms and key words. The inclusion criteria were systematic reviews or in vitro controlled trials on permanent mature teeth or models simulating the root canal system involving a sonic or ultrasonic irrigation group and a control group of conventional needle irrigation. Two reviewers independently selected articles to include according to the inclusion criteria, extracted data from the articles and assessed the methodological quality of the included studies. The data items were arranged in tables. Results: From 811 studies, 17 in vitro studies and 3 systematic reviews were included. EndoActivator and EDDY were the most sonic devices used, whereas several ultrasonic devices were tested for passive ultrasonic irrigation. Debris removal was assessed either on root canal walls or isthmuses or both. The risk of bias and quality of the selected studies were qualified as moderate to high according to the JBI (Joanna Briggs Institute) and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) checklists. Overall, the findings confirmed superiority of the two agitation techniques over conventional irrigation and most of the studies showed no significant differences between sonic and ultrasonic irrigation in debris removal, however a moderate level of evidence showed superiority of ultrasonic irrigation. Conclusion: It may be concluded that sonic and ultrasonic activation of the irrigants are beneficial in hard tissue debris removal when compared to conventional needle irrigation, yet, the current data could not find significant differences between the two techniques.

Failure due to metallosis after cruciate retaining total knee replacement

Background: Rupture of PCL on cruciate retaining TKA can cause abnormal accelerated wear of polyethylene component which may result in metal/metal articulation and development of massive infiltration of metal debris in the periprosthetic soft tissue (metallosis). Patient and methods: Eight cases (Five females, 3 males, mean age 64.6 years) with failed primary cruciate retaining knee arthroplasty were retrospectively studied. Revisions were performed after a mean of 59.8 months due to pain and instability. All the patients had variable degrees of clinically relevant posterior knee instability. Infection was excluded in all cases through microbiological examination and synovial fluid analysis. Results: Abnormal direct metal-on-metal articulation between the femoral component and the tibial base plate with advanced polyethylene wear were found intraoperatively in all cases in addition to extensive tissues black staining, advanced osteolysis and pseudotumor formation. All cases were managed by single stage revision surgery with implant removal, profound synovectomy and revision using a more constrained modular revision knee system. Conclusion: Metallosis after total knee arthroplasty is a rare situation that should be suspected in total knee arthroplasty cases with radiologically evident advanced polyethylene wear especially in cruciate retaining knee systems. It could lead to significant osteolysis making revision surgery technically challenging.

Debris Removal by Activation of Endodontic Irrigants in Complex Root Canal Systems: A Standardized In-Vitro-Study

Aim of the study was to develop a standardized model system to investigate endodontic irrigation techniques and assess the efficiency of different activation methods on the removal of hard tissue debris in complex root canal systems. Mesial roots of mandibular molars were firstly scanned by micro-computed tomography (µCT) and allocated to three groups of irrigant activation: sonic activation (EDDY, VDW, Munich, Germany), laser activation (AutoSWEEPS, FOTONA, Ljubljana, Slovenia) and conventional needle irrigation (control). Roots were fixed in individual 3D-printed holders to facilitate root canal enlargement under constant irrigation with NaOCl (5%). To enable standardized quantification of remaining debris, BaSO4-enriched dentine powder was compacted into the canals, followed by another µCT-scan. The final irrigation was performed using 17% ethylenediaminetetraacetic acid (EDTA) and 5% sodium hypochlorite (NaOCl) with the respective activation method, and the volume of remaining artificial debris was quantified after a final µCT-scan. The newly developed model system allowed for reliable, reproducible and standardized assessment of irrigation methods. Activation of the irrigant proved to be significantly more effective than conventional needle irrigation regarding the removal of debris, which persisted particularly in the apical third of the root canal in the control group. The efficiency of irrigation was significantly enhanced with laser- and sonic-based activation, especially in the apical third.

Wound irrigation for preventing surgical site infections.

Wound irrigation (i.e. washing out a wound before wound closure) aims to reduce the microbial burden by removing tissue debris, metabolic waste, and tissue exudate from the surgical field before site closure. Although it is a popular procedure in every day surgical practice, the lack of procedure standardization, leads to studies with high heterogeneity and often controversial results. Thus, there are studies that advocate its use, while others discourage its implementation in clinical practice to reduce the risk of surgical site infection. The present article reviews the current literature on wound irrigation for preventing surgical site infections. Several irrigants are presented. Chlorexidine is generally considered to be less effective than povidone-iodine, while antibiotics are not that common nowadays, as they require prolonged exposure with the target to act. Hydrogen peroxide has several potential complications, which eliminate its use. Any differences in the incidence of surgical site infections between different irrigants, especially between antibacterial and non-bacterial ones, should be viewed sceptically. More randomized controlled studies are needed to provide better quality of evidence regarding the irrigants' effectiveness and safety.

Macrophage phagocytosis after spinal cord injury: when friends become foes.

After spinal cord injury, macrophages can exert either beneficial or detrimental effects depending on their phenotype. Aside from their critical role in inflammatory responses, macrophages are also specialized in the recognition, engulfment, and degradation of pathogens, apoptotic cells, and tissue debris. They promote remyelination and axonal regeneration by removing inhibitory myelin components and cellular debris. However, excessive intracellular presence of lipids and dysregulated intracellular lipid homeostasis result in the formation of foamy macrophages. These develop a pro-inflammatory phenotype that may contribute to further neurological decline. Additionally, myelin-activated macrophages play a crucial role in axonal dieback and retraction. Here, we review the opposing functional consequences of phagocytosis by macrophages in spinal cord injury, including remyelination and regeneration versus demyelination, degeneration, and axonal dieback. Furthermore, we discuss how targeting the phagocytic ability of macrophages may have therapeutic potential for the treatment of spinal cord injury.

Revealing Inflammatory Indications Induced by Titanium Alloy Wear Debris in Periprosthetic Tissue by Label-Free Correlative High-Resolution Ion, Electron and Optical Microspectroscopy.

The metallic-associated adverse local tissue reactions (ALTR) and events accompanying worn-broken implant materials are still poorly understood on the subcellular and molecular level. Current immunohistochemical techniques lack spatial resolution and chemical sensitivity to investigate causal relations between material and biological response on submicron and even nanoscale. In our study, new insights of titanium alloy debris-tissue interaction were revealed by the implementation of label-free high-resolution correlative microscopy approaches. We have successfully characterized its chemical and biological impact on the periprosthetic tissue obtained at revision surgery of a fractured titanium-alloy modular neck of a patient with hip osteoarthritis. We applied a combination of photon, electron and ion beam micro-spectroscopy techniques, including hybrid optical fluorescence and reflectance micro-spectroscopy, scanning electron microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), helium ion microscopy (HIM) and micro-particle-induced X-ray emission (micro-PIXE). Micron-sized wear debris were found as the main cause of the tissue oxidative stress exhibited through lipopigments accumulation in the nearby lysosome. This may explain the indications of chronic inflammation from prior histologic examination. Furthermore, insights on extensive fretting and corrosion of the debris on nm scale and a quantitative measure of significant Al and V release into the tissue together with hydroxyapatite-like layer formation particularly bound to the regions with the highest Al content were revealed. The functional and structural information obtained at molecular and subcellular level contributes to a better understanding of the macroscopic inflammatory processes observed in the tissue level. The established label-free correlative microscopy approach can efficiently be adopted to study any other clinical cases related to ALTR.

Nuclear Magnetic Resonance Microimaging for the Qualitative Assessment of Root Canal Treatment: An Ex Vivo Preliminary Study.

Aim: To assess the potential ability of nuclear magnetic resonance micro-imaging (mMRI) to visualize and identify soft tissue debris and unfilled spaces inside radicular canals in endodontic treated extracted teeth, for understanding the causes of treatment failure. Toward this goal, multi-parametric mMRI and cone beam computed tomography (CBCT) were compared. Methodology: A non-recoverable root treated human tooth was extracted due to endodontic failure and excessive mobility. It was examined with both CBCT and mMRI: CBCT was performed with 0.125 mm voxel size (GXCB-500, Kavo-Gendex, Brea, CA, USA) and mMRI was performed with a spectrometer operating at 9.4T magnetic field (Bruker Avance-400, Bruker, Billerica, MA, USA). The mMRI images were obtained with a microimaging probe. Relaxation times (T1 and T2) and diffusion-weighted acquisition sequences were used to obtain multi-parametric maps of the extracted tooth (slice thickness of 200 µm and in plane resolution of 30 × 30 µm2). Results: T1 and T2 maps identified unfilled spaces around and close to Gutta-percha cones instead of CBCT images that were not able to highlight this aspect. T1, T2 and apparent diffusion coefficient (ADC) assumed different values in dentine and in voids, characterized by different dimensions. Moreover, they were able to discriminate between infiltrations of water only and deposits of biological material. Because Gutta-percha cones are constituted of hard, non-porous material, they do not provide a signal and in mMRI images appear as zones of noise. Conclusions: Unlike the CBCT exam, mMRI can detect soft tissue debris and unfilled spaces inside radicular canals. Therefore, this in vitro study showed the potential of mMRI to evaluate the quality of the root canal treatment, suggesting its potential benefit in determining the causes of endodontic failure, without the use of ionizing radiation.

Influence of ultraconservative access cavities on instrumentation efficacy with XP-endo Shaper and Reciproc, filling ability and load capacity of mandibular molars subjected to thermomechanical cycling.

To evaluate the influence of ultraconservative access cavities (UltraAC) on canal shaping and filling ability and load capacity of mandibular molars after root canal preparation with XP-endo Shaper (XP) or Reciproc (RC), under simulated clinical conditions. Traditional access cavities (TradAC) were used for comparison. Forty extracted mandibular molars were scanned by micro-computed tomographic and, based on similar anatomical features, were divided into four groups (n=10), according to the type of access cavity and canal instrumentation protocol: TradAC/RC, TradAC/XP, UltraAC/RC and UltraAC/XP. All root canal procedures were performed with the teeth placed in a dental mannequin. Teeth were scanned after root canal instrumentation and filling. Unprepared canal area, dentine removed, accumulated hard tissue debris (AHTD), canal transportation, presence of voids and filling material remnants within the pulp chamber were analysed. After restorative procedures, the teeth were subjected to thermomechanical cycling and to a load capacity test. Statistical analyses were performed using two-way anova test, considering the randomized blocks design (P<0.05). The percentage of unprepared canal area was significantly lower in TradAC groups when compared to UltraAC groups (P<0.05), regardless of the instrument used. The UltraAC/XP group had significantly lower percentage of root dentine removed when compared to other groups (P<0.05). UltraAC/XP and TradAC/XP groups had significantly lower percentages of AHTD than UltraAC/RC and TradAC/RC groups (P<0.05). Regarding canal transportation, in the MB root canals, the TradAC/XP group had significantly lower values than other groups (P<0.05). In general, in ML and distal root canals, TradAC/XP and UltraAC/XP groups had significantly lower values of canal transportation when compared to other groups (P<0.05). Moreover, the UltraAC/RC had the greatest canal transportation values in MB and distal canals. The UltraAC groups had significantly greater percentages of voids and volume of remaining root filling material within the pulp chamber after cleaning procedures than TradAC groups (P<0.05). There was no difference in the load capacity amongst groups (P<0.05). The UltraAC/XP and UltraAC/RC groups had significantly greater areas of unprepared canal walls, significantly more voids and volume of root filling material remnants within the pulp chamber after canal filling. UltraAC/XP was associated with significantly less root dentine removal and significantly more AHTD whilst TradAC/XP had overall significantly less canal transportation. No differences were observed in the load capacity amongst groups.

Unprepared surface areas, accumulated hard tissue debris, and dentinal crack formation after preparation using reciprocating or rotary instruments: a study in human cadavers.

This study using contralateral teeth from human cadavers assessed the amount of unprepared wall surface areas (USA), accumulated hard tissue debris (AHTD), and dentinal crack formation after root canal preparation using either reciprocating or rotary instruments. Incisors with a single root canal from 11 human mandibles had their root canals prepared with Reciproc or Mtwo. Each contralateral tooth was treated with one of the test instruments in order to create matched pairs. Micro-CT scans were taken before and after preparation to instrument sizes 40 and 50 in both groups. USA and AHTD were evaluated in the full canal length or the apical portion only. Crack formation was also evaluated in the full root length. After size 40, no significant differences in USA and AHTD were observed in the full canal length (P > .05). Separate analysis of the apical 4-mm canal revealed no difference in AHTD, but significantly more USA with Mtwo than Reciproc (P < .05). After size 50, the amount of USA was similar between groups both in the full canal and in the apical canal (P > .05). More AHTD were observed in the full canal after using Mtwo size 50 (P < .05), but no difference occurred in the apical canal only (P > .05). Intragroup analyses showed a significant decrease of USA and a significant increase of AHTD when preparation size increased from 40 to 50 (P < .05). In teeth without any pre-existing detectable dentinal defect (n = 38), crack formation occurred in 4 teeth, 2 from each preparation system. Reciproc instrument size 40 resulted in more prepared areas in the apical canal than Mtwo instrument of the same size. However, the amount of AHTD did not differ between them at this file size. Canal enlargement to size 50 prepared more walls but created more debris. Dentinal defects were produced after preparation with both systems.

Newly developed SYBR Green-based quantitative real-time PCRs revealed coinfection evidence of Angiostrongylus cantonensis and A. malaysiensis in Achatina fulica existing in Bangkok Metropolitan, Thailand

Angiostrongylus cantonensis is a well-known pathogen causing eosinophilic meningitis associated with angiostrongyliasis. Humans, as accidental hosts, are infected by consuming undercooked snails containing third-stage larvae. A. malaysiensis is closely related to A. cantonensis and has been described as a potential human pathogen. The two species distribution was recently reported to overlap in the same endemic area, particularly in the Indochina Peninsula. Similar morphological characteristics of the third-stage larva in the snail-intermediate host often lead to misidentification of the two species. Thus, we aimed to develop a sensitive and specific method to detect and discriminate Angiostrongylus third-stage larva by designing species-specific primers based on the mitochondrial cytochrome b gene. We developed the SYBR Green quantitative real-time PCR (qPCR) method for two species-specific detection assays, which could be conducted simultaneously. The method was subsequently employed to detect and identify third-stage larvae of Angiostrongylus isolated from infected Achatina fulica collected from six public parks in Bangkok Metropolitan, Thailand. The method was also a preliminary applied to detect parasite tissue debris in the patients' cerebrospinal fluid (CSF). SYBR Green qPCRs quantitatively detected approximately 10−4 ng of genomic DNA from one larva, facilitating species-specific detection. Based on the pools of third-stage larvae isolated individually from the tissue of each infected A. fulica collected from the public parks, the qPCR results revealed that A. malaysiensis was the predominant species infecting 5.26% of the collected snails. In comparison, coinfection between A. malaysiensis and A. cantonensis was 5.97%, and no single infection of A. cantonensis was detected in A. fulica. Our SYBR Green qPCR method is a useful and inexpensive technique for A. cantonensis and A. malaysiensis discrimination, and the method has sufficient sensitivity to detect isolated larvae from a snail-intermediate host. The ratio of A. cantonensis and A. malaysiensis larvae infecting the snails can also be estimated simultaneously. Our qPCRs can be employed in a molecular survey of A. cantonensis and A. malaysiensis within intermediate hosts and for clinical diagnosis of angiostrongyliasis with CSF specimens in future studies.

Preparation Ability of ProTaper Next and XP-endo Shaper Instruments in Isthmus-containing Root Canal System

ABSTRACT Aim and objective This research compares the abilities of the preparation of ProTaper Next (PTN; Dentsply-Maillefer) and XP-endo Shaper (XPS; FKG, Switzerland) files in mesial canals of lower molars with separate binary canals and one foramen with isthmus connection using μCT imaging. Materials and methods The comparison showed 20 roots matched according to the similarities in preoperative canal volume, specimen length, and root curvature using preoperative scans, and then they were indiscriminately separated into two groups and prepared either with PTN or XPS instruments. After chemomechanical preparation, the roots were resubmitted to postoperative scans. Results There was no variance in instrument systems for the volume of removed dentine, surface area as well as the amount of accumulated debris in the isthmus region (p &gt;0.05). Change in canal surface area and amount of accumulated hard tissue debris (AHTD) was more in the PTN group for total root canal space (p &lt;0.05). PTN instruments increased surface area in a shorter period. Conclusion: Both instrument systems with different design and metallurgic properties had reached the desired volume in different periods; however, neither technique was able to fully prepare the isthmus-containing mesial roots of lower molars. How to cite this article Sarıkahya M, Alaçam T. Preparation Ability of ProTaper Next and XP-endo Shaper Instruments in Isthmus-containing Root Canal System. Cons Dent Endod J 2020;5(2):28–35.

Biotribological Tests of Osteochondral Grafts after Treatment with Pro-Inflammatory Cytokines.

ObjectiveDuring osteoarthritis progression, cartilage degrades in a manner that influences its biomechanical and biotribological properties, while chondrocytes reduce the synthesis of extracellular matrix components and become apoptotic. This study investigates the effects of inflammation on cartilage under biomechanical stress using biotribological tests.MethodsBovine osteochondral grafts from five animals were punched out from the medial condyle and treated with or without pro-inflammatory cytokines (interleukin-1β [IL-1β], tumor necrosis factor-α [TNF-α], IL-6) for 2 weeks. After incubation, biotribological tests were performed for 2 hours (alternating 10 minutes test and pause respectively at 39°C, 180 N, 1 Hz, and 2 mm stroke). Before and after testing, the cartilage surface was imaged with a 3-dimensional microscope. During testing, the coefficient of friction (COF) was measured, while gene expression analysis and investigation of metabolic activity of chondrocytes were carried out after testing. Histological sections of the tissue and wear debris from the test fluid were also analyzed.ResultsAfter biotribological tests, surface cracks were found in both treated and untreated osteochondral grafts. In treated grafts, the COF increased, and the proteoglycan content in the cartilage tissue decreased, leading to structural changes. Chondrocytes from treated grafts showed increased expression of genes encoding for degradative enzymes, while cartilage-specific gene expression and metabolic activity exhibited no significant differences between treated and untreated groups. No measurable difference in the wear debris in the test fluid was found.ConclusionsTreatment of osteochondral grafts with cytokines results in a significantly increased COF, while also leading to significant changes in cartilage proteoglycan content and cartilage matrix compression during biotribological tests.