scholarly journals Estimated functional space of centric condyle positions in temporomandibular joints of asymptomatic individuals using MRI

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aleš Čelar ◽  
André Gahleitner ◽  
Stefan Lettner ◽  
Josef Freudenthaler
Keyword(s):  
Confidence Interval ◽  
Functional Space ◽  
Centric Relation ◽  
Temporomandibular Joints ◽  
Minimal Convex ◽  
Mri Scans ◽  
Confidence Ellipses ◽  
Asymptomatic Individuals ◽  
Asymptomatic Subjects

Abstract Magnetic resonance imaging (MRI) studies on centric condyle positions lack 3D comparisons of guided and unguided methods, which are used for accomplishing centric relation reference positions. The purpose of this study was to describe the space, in which mandibular condyles are placed in vivo by dental intercuspation, Dawson’s bimanual manipulation, and neuromuscular position. Twenty asymptomatic individuals aged 23 to 37 years underwent separate bite registrations using bimanual manipulation and the unguided neuromuscular technique. Subsequent 3-Tesla MRI scans of both temporomandibular joints yielded 3D data of the most superior condylar points at maximum intercuspation and both centric relation positions. We found concentric condyle positions in maximum intercuspation but considerable variation of condyle position after bimanual manipulation and neuromuscular technique. Their 95% predictive confidence ellipses overlapped substantially and created a space of reference positions. Its smallest volume averaged 2 mm3 for a minimal convex hull (95% confidence interval 1.1–3.2) and 3.5 mm3 for a minimal ellipsoid hull (95% confidence interval 1.8–5.4). Visualized in vivo by MRI, condyle positions at bimanual manipulation and neuromuscular position were not predictable and showed substantial variation in asymptomatic subjects. Clinicians should be aware of the functional space and its effect on dental intercuspation.

A STUDY OF CONDYLAR POSITION IN CENTRIC RELATION AND MAXIMAL INTERCUSPATION USING CONEBEAM TOMOGRAPHY

2019 ◽  
pp. 84-92
Author(s):  
Anh Chi Phan ◽  
Xuan Anh Ngoc Ho
Keyword(s):  
Dental Students ◽  
Cone Beam ◽  
Test Results ◽  
Reference Position ◽  
Centric Relation ◽  
Temporomandibular Joints ◽  
Significant Difference ◽  
Mandibular Fossa ◽  
Condylar Position ◽  
Cone Beam Tomography

Background: The condylar position discrepancy between centric relation and maximal intercuspation has been still a controversial issue. Aims: To compare the condylar position between centric relation and maximal intercuspation using cone-beam tomography in patients without temporomandibular joints disorder. Materials and methods: To assess the condylar position in centric relation and maximal intercuspation using cone-beam tomography on 40 fifth-year and sixth-year dental students of Hue University of Medicine and Pharmacy without temporomandibular joints disorder. The condylar positions are assessed following Sener classification (2009) and are compared between centric relation and maximal intercuspation using pairedsamples t-test and Mann-Whitney U-test. Results: Among 480 condye-to-fossa measurement pairs, there are 91.2% pairs having difference between two reference position but there is no significant difference. The condylar position at the superior of mandibular fossa has the greatest percentage in both centric relation and maximal intercuspation (43.8% in centric relation and 51.2% in maximal intercuspation). This greatest percentage is followed by the condylar position at posterior of mandibular fossa (32.5% in centric relation and 36.3% in maximal intercuspation). Lastly, the condylar position at the anterior of mandibular fossa has the fewest percentage (23.7% in centric relation and 12.5% in maximal intercuspation). Conclusion: There is no significant difference of condylar position between centric relation and maximal intercuspation in patients without temporomandibular joints disorder. Key words: Condylar position, centric relation, maximal intercuspation, cone-beam tomography

Impact of mandibular prognathism on morphology and loadings in temporomandibular joints

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jingheng Shu ◽  
Quanyi Wang ◽  
Desmond Y.R. Chong ◽  
Zhan Liu
Keyword(s):  
Finite Element Analysis ◽  
Pearson Correlation ◽  
Morphological Parameters ◽  
Element Analysis ◽  
Mandibular Prognathism ◽  
Temporomandibular Joints ◽  
Pearson Correlation Analysis ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Asymptomatic Subjects

AbstractLoadings in temporomandibular joints (TMJs) are essential factors in dysfunction of TMJs, and are barely noticed in treatment of maxillofacial deformity. The only approach, which can access stresses in TMJs, could expend day’s even weeks to complete. The objective of the study was to compare the differences of the morphological and biomechanical characteristics of TMJs between asymptomatic subjects and patients with mandibular prognathism, and to preliminarily analyze the connection between the two kinds of characteristics. Morphological measurements and finite element analysis (FEA) corresponding to the central occlusion were carried out on the models of 13 mandibular prognathism patients and 10 asymptomatic subjects. The results indicated that the joint spaces of the patients were significantly lower than those of the asymptomatic subjects, while the stresses of patients were significantly greater than those of asymptomatic subjects, especially the stresses on discs. The results of Pearson correlation analysis showed that weak or no correlations were found between the von Mises stresses and the joint spaces of asymptomatic subjects, while moderate, even high correlations were found in the patients. Thus, it was shown to be a feasible way to use morphological parameters to predict the internal loads of TMJs.

scholarly journals ZN148 Is a Modular Synthetic Metallo-β-Lactamase Inhibitor That Reverses Carbapenem Resistance in Gram-Negative Pathogens In Vivo

2020 ◽  
Vol 64 (6) ◽  
Author(s):  
Ørjan Samuelsen ◽  
Ove Alexander Høgmoen Åstrand ◽  
Christopher Fröhlich ◽  
Adam Heikal ◽  
Susann Skagseth ◽  
...  
Keyword(s):  
Active Site ◽  
Therapeutic Potential ◽  
Treatment Options ◽  
Carbapenem Resistance ◽  
Functional Space ◽  
Bactericidal Effect ◽  
Gram Negative ◽  
Content Type

ABSTRACT Carbapenem-resistant Gram-negative pathogens are a critical public health threat and there is an urgent need for new treatments. Carbapenemases (β-lactamases able to inactivate carbapenems) have been identified in both serine β-lactamase (SBL) and metallo-β-lactamase (MBL) families. The recent introduction of SBL carbapenemase inhibitors has provided alternative therapeutic options. Unfortunately, there are no approved inhibitors of MBL-mediated carbapenem-resistance and treatment options for infections caused by MBL-producing Gram-negatives are limited. Here, we present ZN148, a zinc-chelating MBL-inhibitor capable of restoring the bactericidal effect of meropenem and in vitro clinical susceptibility to carbapenems in >98% of a large international collection of MBL-producing clinical Enterobacterales strains (n = 234). Moreover, ZN148 was able to potentiate the effect of meropenem against NDM-1-producing Klebsiella pneumoniae in a murine neutropenic peritonitis model. ZN148 showed no inhibition of the human zinc-containing enzyme glyoxylase II at 500 μM, and no acute toxicity was observed in an in vivo mouse model with cumulative dosages up to 128 mg/kg. Biochemical analysis showed a time-dependent inhibition of MBLs by ZN148 and removal of zinc ions from the active site. Addition of exogenous zinc after ZN148 exposure only restored MBL activity by ∼30%, suggesting an irreversible mechanism of inhibition. Mass-spectrometry and molecular modeling indicated potential oxidation of the active site Cys221 residue. Overall, these results demonstrate the therapeutic potential of a ZN148-carbapenem combination against MBL-producing Gram-negative pathogens and that ZN148 is a highly promising MBL inhibitor that is capable of operating in a functional space not presently filled by any clinically approved compound.

scholarly journals Cerebral Glucose and Dopa Metabolism in Movement Disorders

1987 ◽  
Vol 14 (S3) ◽  
pp. 448-451 ◽  
Author(s):  
W.R. Wayne Martin ◽  
Michael R. Hayden
Keyword(s):  
At Risk ◽  
Glucose Metabolism ◽  
Normal Subjects ◽  
Cerebral Glucose Metabolism ◽  
Nigrostriatal Pathway ◽  
Age Related ◽  
Positron Emission ◽  
Asymptomatic Individuals ◽  
Regional Cerebral Glucose Metabolism

ABSTRACT:The development of positron emission tomography (PET) has enabled us to perform in vivo measurements of certain aspects of regional cerebral function. Regional cerebral glucose metabolism may be readily quantified with [18F] fluoro-2-deoxyglucose (FDG) and presynaptic dopaminergic function may be studied with the labelled dopa analog 6-[18F] fluoro-L-dopa. We have applied a model to the analysis of 6-FD/PET data with which in vivo age-related changes in dopaminergic function may be demonstrated in normal subjects. With this technique, we have studied a series of asymptomatic MPTP-exposed subjects and have shown evidence of subclinical nigrostriatal pathway damage. Studies of regional cerebral glucose metabolism with FDG in early Huntington's disease have shown a characteristic impairment in caudate function which precedes the development of caudate atrophy. In addition, some asymptomatic individuals who are at risk for HD have caudate hypometabolism. We feel that, at the present time, PET provides information which is complementary to the clinical examination in establishing a diagnosis of HD. In the future these studies may also help in the investigation of at risk individuals

scholarly journals Validation of a Monte Carlo Modelling Based Dosimetry of Extraoral Photobiomodulation

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2207
Author(s):  
Anna N. Yaroslavsky ◽  
Amy F. Juliano ◽  
Ather Adnan ◽  
Wayne J. Selting ◽  
Tyler W. Iorizzo ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Light Emitting Diode ◽  
Morphological Data ◽  
Transmitted Power ◽  
Light Dosimetry ◽  
Mean Values ◽  
Mri Scans ◽  
The Difference

An in vivo validation study was performed to confirm the accuracy of extraoral photobiomodulation therapy (PBMT) dosimetry determined by modelling. The Monte Carlo technique was utilized to calculate the fluence rate and absorbed power of light delivered through multi-layered tissue. Optical properties used during Monte Carlo simulations were taken from the literature. Morphological data of four study volunteers were acquired using magnetic resonance imaging (MRI) scans. Light emitting diode (LED) coupled to a power meter were utilized to measure transmitted power through each volunteer’s cheek, in vivo. The transmitted power determined by Monte Carlo modelling was compared to the in vivo measurements to determine the accuracy of the simulations. Experimental and simulation results were in good agreement for all four subjects. The difference between the mean values of the measured transmission was within 12% from the respective transmission obtained using Monte Carlo simulations. The results of the study indicate that Monte Carlo modelling is a robust and reliable method for light dosimetry.

Imaging of microvascular disease

2021 ◽  
pp. 481-494
Author(s):  
Paolo G. Camici ◽  
Ornella Rimoldi
Keyword(s):  
Myocardial Ischaemia ◽  
Imaging Techniques ◽  
Microvascular Disease ◽  
Microvascular Dysfunction ◽  
Microvascular Function ◽  
Coronary Microvascular Dysfunction ◽  
Maximal Increase ◽  
Asymptomatic Subjects ◽  
Coronary Microvascular Function

Beside obstructive disease of the epicardial coronary arteries dysfunction of the coronary microvasculature has emerged in the past 20 years as an additional mechanism of myocardial ischaemia. The coronary microvasculature cannot be directly visualized in vivo, therefore, both invasive and non-invasive techniques, have been developed to assess parameters that depend directly on coronary microvascular function. Studies at the microcirculatory level entail the use of vasodilators to obtain near-maximal vasodilation. The ratio of the maximal increase of blood flow above its resting value the coronary flow reserve (CFR) allows to gain an insight into the integrated circulatory function. The diagnostic accuracy of imaging techniques can be exploited to detect impairments of myocardial perfusion in asymptomatic subjects with cardiovascular risk factors. The assessment of the coronary microvascular function has provided novel details on the pathophysiological role of coronary microvascular dysfunction in the development of myocardial ischaemia bearing also important prognostic implications.

scholarly journals Amyloid- and tau-PET imaging in a familial prion kindred

2018 ◽  
Vol 4 (6) ◽  
pp. e290 ◽  
Author(s):  
David T. Jones ◽  
Ryan A. Townley ◽  
Jonathan Graff-Radford ◽  
Hugo Botha ◽  
David S. Knopman ◽  
...  
Keyword(s):  
Case Series ◽  
High Specificity ◽  
Disease Course ◽  
Therapeutic Trials ◽  
In Vivo Detection ◽  
Pet Tracer ◽  
Fourth Decade ◽  
Tau Pet ◽  
Asymptomatic Individuals

ObjectiveTo study the in vivo binding properties of 18F-AV-1451 (tau-PET) and Pittsburgh compound B (PiB-PET) in a unique kindred with a familial prion disorder known to produce amyloid plaques composed of prion protein alongside Alzheimer disease (AD)–like tau tangles.MethodsA case series of 4 symptomatic family members with the 12-octapeptide repeat insertion in the PRNP gene were imaged with 3T MRI, PiB-PET, and tau-PET in their fourth decade of life.ResultsThere was significant neocortical uptake of the tau-PET tracer in all 4 familial prion cases. However, PiB-PET images did not demonstrate abnormally elevated signal in neocortical or cerebellar regions for any of the patients.ConclusionsIn vivo detection of molecular hallmarks of neurodegenerative diseases will be a prerequisite to well-conducted therapeutic trials. Understanding the in vivo behavior of these PET biomarkers in the setting of various neurodegenerative processes is imperative to their proper use in such trials and for research studies focused on the basic neurobiology of neurodegeneration. This study supports the high specificity of neocortical 18F-AV-1451 binding to AD-like tau and the lack of PiB binding to PrP plaques. It is uncertain how early in the disease course tau pathology appears in the brains of individuals who carry this PRNP gene mutation or how it evolves throughout the disease course, but future longitudinal 18F-AV-1451 imaging of symptomatic and asymptomatic individuals in this kindred will help address these uncertainties.

scholarly journals Diagnostic Validity of Digital Imaging Fiber-Optic Transillumination (DIFOTI) and Near-Infrared Light Transillumination (NILT) for Caries in Dentine

2020 ◽  
Vol 9 (2) ◽  
pp. 420
Author(s):  
Ana Marmaneu-Menero ◽  
José Enrique Iranzo-Cortés ◽  
Teresa Almerich-Torres ◽  
José Carmelo Ortolá-Síscar ◽  
José María Montiel-Company ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Qualitative Analysis ◽  
Near Infrared ◽  
Meta Analysis ◽  
Infrared Light ◽  
X Rays ◽  
Carious Lesions ◽  
Sensitivity Specificity

The objective of the study is to analyse the available evidence for the validity of the transillumination method in the diagnosis of interproximal caries. Bibliographic searches were carried out in three data bases (PubMed, Embase, Scopus) with the key words “Transillumination AND caries”. A total of 11 studies were selected for the qualitative analysis and meta-analysis. In the qualitative analysis, both in vivo and in vitro studies were included. The gold standards were tomography, digital radiography, and clinical visual diagnosis. The meta-analysis determined the sensitivity, specificity, and area below the ROC curve relative to the transillumination method in the diagnosis of caries in dentine. Meta-analysis results obtained for transillumination gave a sensitivity value of 0.69 (confidence interval: 0.54–0.81), a specificity value of 0.89 (confidence interval: 0.61–0.98), while giving an AUC value of 0.79 (confidence interval: 0.67–0.87). Transillumination is a method offering moderate validity in the diagnosis of carious lesions in dentine, there is no strong evidence that may enable us to affirm that transillumination may fully substitute X-rays in the complementary diagnosis of carious lesions

scholarly journals Cutting Edge: Retrobulbar Inflammation, Adipogenesis, and Acute Orbital Congestion in a Preclinical Female Mouse Model of Graves' Orbitopathy Induced by Thyrotropin Receptor Plasmid-in Vivo Electroporation

Endocrinology ◽  
2013 ◽  
Vol 154 (9) ◽  
pp. 3008-3015 ◽  
Author(s):  
Sajad Moshkelgosha ◽  
Po-Wah So ◽  
Neil Deasy ◽  
Salvador Diaz-Cano ◽  
J Paul Banga
Keyword(s):  
Therapeutic Interventions ◽  
Preclinical Model ◽  
Orbital Tissue ◽  
Mri Scans ◽  
A Subunit ◽  
Graves Orbitopathy ◽  
Orbital Muscle ◽  
Magnetic Resonance Imaging Mri ◽  
Blocking Antibodies

Graves' orbitopathy (GO) is a complication in Graves' disease (GD) but mechanistic insights into pathogenesis remain unresolved, hampered by lack of animal model. The TSH receptor (TSHR) and perhaps IGF-1 receptor (IGF-1R) are considered relevant antigens. We show that genetic immunization of human TSHR (hTSHR) A-subunit plasmid leads to extensive remodeling of orbital tissue, recapitulating GO. Female BALB/c mice immunized with hTSHR A-subunit or control plasmids by in vivo muscle electroporation were evaluated for orbital remodeling by histopathology and magnetic resonance imaging (MRI). Antibodies to TSHR and IGF-1R were present in animals challenged with hTSHR A-subunit plasmid, with predominantly TSH blocking antibodies and were profoundly hypothyroid. Orbital pathology was characterized by interstitial inflammation of extraocular muscles with CD3+ T cells, F4/80+ macrophages, and mast cells, accompanied by glycosaminoglycan deposition with resultant separation of individual muscle fibers. Some animals showed heterogeneity in orbital pathology with 1) large infiltrate surrounding the optic nerve or 2) extensive adipogenesis with expansion of retrobulbar adipose tissue. A striking finding that underpins the new model were the in vivo MRI scans of mouse orbital region that provided clear and quantifiable evidence of orbital muscle hypertrophy with protrusion (proptosis) of the eye. Additionally, eyelid manifestations of chemosis, including dilated and congested orbital blood vessels, were visually apparent. Immunization with control plasmids failed to show any orbital pathology. Overall, these findings support TSHR as the pathogenic antigen in GO. Development of a new preclinical model will facilitate molecular investigations on GO and evaluation of new therapeutic interventions.

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