Chlorhexidine Arrests Subclinical Degradation of Dentin Hybrid Layers in vivo

The recent paradigm that endogenous collagenolytic and gelatinolytic activities derived from acid-etched dentin result in degradation of hybrid layers requires in vivo validation. This study tested the null hypothesis that there is no difference between the degradation of dentin bonded with an etch-and-rinse adhesive and that in conjunction with chlorhexidine, an MMP inhibitor, applied after phosphoric-acid-etching. Contralateral pairs of bonded Class I restorations in primary molars of clinical subjects were retrieved after a six-month period of intra-oral functioning and processed for transmission electron microscopy. Hybrid layers from the chlorhexidine-treated teeth exhibited normal structural integrity of the collagen network. Conversely, abnormal hybrid layers were seen in the control teeth, with progressive disintegration of the fibrillar network, to the extent that it was beyond detection by collagen staining. Self-destruction of collagen matrices occurs rapidly in resin-infiltrated dentin in vivo and may be arrested with the use of chlorhexidine as an MMP inhibitor.

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Collagen Degradation in Endodontically Treated Teeth after Clinical Function

Journal of Dental Research ◽

10.1177/154405910408300512 ◽

2004 ◽

Vol 83 (5) ◽

pp. 414-419 ◽

Cited By ~ 51

Author(s):

M. Ferrari ◽

P.N. Mason ◽

C. Goracci ◽

D.H. Pashley ◽

F.R. Tay

Keyword(s):

Structural Integrity ◽

Zinc Phosphate ◽

Bacterial Colonization ◽

Collagenolytic Activity ◽

Endodontically Treated Teeth ◽

Collagen Matrices ◽

Transmission Electron ◽

The Status ◽

Root Dentin

Endodontically treated teeth restored with posts are susceptible to coronal leakage after long-term function. We hypothesize that demineralized collagen matrices (DCMs) created in dentin by acidic zinc phosphate cement within the dowel spaces degrade with time. Forty-two post-restored teeth were extracted after three periods of clinical service and were examined, by means of scanning and transmission electron microscopy, for the status of the DCMs. SEM revealed a progressive degradation of the DCMs, becoming less dense after 3 to 5 years, losing structural integrity after 6 to 9 years, and partially disappearing after 10 to 12 years. TEM revealed evidence of collagenolytic activity within the DCMs, with loss of cross-banding and unraveling into microfibrils, and gelatinolytic activity that resulted in disintegration of the microfibrils. Bacterial colonization and the release of bacterial enzymes and of host-derived matrix metalloproteinases may contribute to the degradation of collagen fibrils in root dentin after clinical function.

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In vitro Remineralization of Severely Compromised Bonded Dentin

Journal of Dental Research ◽

10.1177/0022034510363662 ◽

2010 ◽

Vol 89 (4) ◽

pp. 405-410 ◽

Cited By ~ 21

Author(s):

S. Mai ◽

Y.K. Kim ◽

J. Kim ◽

C.K.Y. Yiu ◽

J. Ling ◽

...

Keyword(s):

Polycarboxylic Acid ◽

Hybrid Layer ◽

Fluid System ◽

Collagen Matrices ◽

Hierarchical Order ◽

Etch And Rinse ◽

Dentin Collagen ◽

Dentin Formation ◽

Hybrid Layers

Biomimetic remineralization is potentially useful for the remineralization of incompletely resin-infiltrated collagen matrices created by etch-and-rinse adhesives. In this study, we tested the hypothesis that structurally altered dentin collagen cannot be remineralized to the same hierarchical order and dimension seen in structurally intact dentin collagen. The remineralization medium consisted of a set Portland cement/simulated body fluid system containing polycarboxylic acid and polyvinylphosphonic acid as biomimetic analogs. Remineralization of air-dried, collapsed hybrid layers was apparent after one month, with hybrid layers remineralized to 80–90% of their thickness after 2–4 months. A hypermineralized layer was seen on the hybrid layer surface, and tubular orifices were occluded with apatite deposits that resembled those present in non-carious cervical dentin. Structurally altered collagen is unlikely to be remineralized to the same hierarchical order and dimension as seen in intact dentin. The aggressively air-dried acid-etched dentin remineralization model also sheds light on the mechanism of sclerotic dentin formation.

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Pharmacokinetic Evaluation of 99mTc-radiolabeled Solid Lipid Nanoparticles and Chitosan Coated Solid Lipid Nanoparticles

Current Drug Metabolism ◽

10.2174/1389200220666191112145808 ◽

2020 ◽

Vol 20 (13) ◽

pp. 1044-1052

Author(s):

Nasrin Abbasi Gharibkandi ◽

Sajjad Molavipordanjani ◽

Jafar Akbari ◽

Seyed Jalal Hosseinimehr

Keyword(s):

Solid Lipid Nanoparticles ◽

Lipid Nanoparticles ◽

High Resistivity ◽

Scanning Calorimetry ◽

Liver Uptake ◽

Solid Lipid ◽

Transmission Electron ◽

Main Portion ◽

Pharmacokinetic Behavior

Background: Solid Lipid Nanoparticles (SLNs) possess unique in vivo features such as high resistivity, bioavailability, and habitation at the target site. Coating nanoparticles with polymers such as chitosan greatly affects their pharmacokinetic behavior, stability, tissue uptake, and controlled drug delivery. The aim of this study was to prepare and evaluate the biodistribution of 99mTc-labeled SLNs and chitosan modified SLNs in mice. Methods: 99mTc-oxine was prepared and utilized to radiolabel pre-papered SLNs or chitosan coated SLNs. After purification of radiolabeled SLNs (99mTc-SLNs) and radiolabeled chitosan-coated SLNs (99mTc-Chi-SLNs) using Amicon filter, they were injected into BALB/c mice to evaluate their biodistribution patterns. In addition, nanoparticles were characterized using Transmission Electron Microscopy (TEM), Fourier-transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRD) and Dynamic Light Scattering (DLS). Results: 99mTc-oxine with high radiochemical purity (RCP~100%) and stability (RCP > 97% at 24 h) was used to provide 99mTc-SLNs and 99mTc-Chi-SLNs with high initial RCP (100%). TEM image and DLS data suggest 99mTc- SLNs susceptibility to aggregation. To that end, the main portion of 99mTc-SLNs radioactivity accumulates in the liver and intestines, while 99mTc-Chi-SLNs sequesters in the liver, intestines and kidneys. The blood radioactivity of 99mTc-Chi-SLNs was higher than that of 99mTc-SLNs by 7.5, 3.17 and 3.5 folds at 1, 4 and 8 h post-injection. 99mTc- Chi-SLNs uptake in the kidneys in comparison with 99mTc-SLNs was higher by 37.48, 5.84 and 11 folds at 1, 4 and 8h. Conclusion: The chitosan layer on the surface of 99mTc-Chi-SLNs reduces lipophilicity in comparison with 99mTc- SLNs. Therefore, 99mTc-Chi-SLNs are less susceptible to aggregation, which leads to their lower liver uptake and higher kidney uptake and blood concentration.

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Mice with cleavage-resistant N-cadherin exhibit synapse anomaly in the hippocampus and outperformance in spatial learning tasks

Molecular Brain ◽

10.1186/s13041-021-00738-1 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

M. Asada-Utsugi ◽

K. Uemura ◽

M. Kubota ◽

Y. Noda ◽

Y. Tashiro ◽

...

Keyword(s):

Memory Function ◽

Three Dimensional ◽

Excitatory Synapses ◽

Missense Mutations ◽

Glutamatergic Synapses ◽

Learning Tasks ◽

Transmission Electron ◽

Nmdar Activation ◽

And Function

AbstractN-cadherin is a homophilic cell adhesion molecule that stabilizes excitatory synapses, by connecting pre- and post-synaptic termini. Upon NMDA receptor (NMDAR) activation by glutamate, membrane-proximal domains of N-cadherin are cleaved serially by a-disintegrin-and-metalloprotease 10 (ADAM10) and then presenilin 1(PS1, catalytic subunit of the γ-secretase complex). To assess the physiological significance of the initial N-cadherin cleavage, we engineer the mouse genome to create a knock-in allele with tandem missense mutations in the mouse N-cadherin/Cadherin-2 gene (Cdh2R714G, I715D, or GD) that confers resistance on proteolysis by ADAM10 (GD mice). GD mice showed a better performance in the radial maze test, with significantly less revisiting errors after intervals of 30 and 300 s than WT, and a tendency for enhanced freezing in fear conditioning. Interestingly, GD mice reveal higher complexity in the tufts of thorny excrescence in the CA3 region of the hippocampus. Fine morphometry with serial section transmission electron microscopy (ssTEM) and three-dimensional (3D) reconstruction reveals significantly higher synaptic density, significantly smaller PSD area, and normal dendritic spine volume in GD mice. This knock-in mouse has provided in vivo evidence that ADAM10-mediated cleavage is a critical step in N-cadherin shedding and degradation and involved in the structure and function of glutamatergic synapses, which affect the memory function.

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Qualitative ultrastructural analysis of the submandibular salivary glands after administration of khat: in vivo study

BMC Research Notes ◽

10.1186/s13104-021-05595-8 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Gamilah Al-Qadhi ◽

Rabab Mubarak

Keyword(s):

Salivary Glands ◽

Arabian Peninsula ◽

Submandibular Salivary Gland ◽

Catha Edulis ◽

Ductal Cells ◽

Cytoplasmic Vacuoles ◽

Transmission Electron ◽

Salivary Gland Cells ◽

Submandibular Salivary Glands

Abstract Objective Khat (Catha edulis Forssk) plant has been widely chewed for its psychostimulatory effects in the African and Arabian Peninsula, particularly in Yemen. Considering the khat leaves are gradually chewed without swallowing, while its active constituents are extracted into saliva, studying the effect of khat on salivary glands is necessary. This work is an extension of the previously published work that studied the effect of khat extract on the rats' submandibular salivary glands in terms of histological and immunohistochemical evaluations. The current research note aimed to better understand this effect on the ultrastructure of submandibular salivary gland cells by using transmission electron microscope. Results Oral administration of khat extract produced degenerative changes in the secretory and ductal cells of rats' submandibular salivary glands. These changes involved irregular boundaries of variable sized-nuclei, dilated RER, cytoplasmic vacuoles as well as swollen and degenerated mitochondria.

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Cemp1-p3 Peptide Promotes the Transformation of Octacalcium Phosphate into Hydroxyapatite Crystals

Crystals ◽

10.3390/cryst10121131 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1131

Author(s):

Maricela Santana ◽

Gonzalo Montoya ◽

Raúl Herrera ◽

Lía Hoz ◽

Enrique Romo ◽

...

Keyword(s):

Electron Microscopy ◽

Octacalcium Phosphate ◽

Sequence Motifs ◽

Simple Method ◽

Transmission Electron ◽

Precursor Phase ◽

Mineralized Tissues ◽

Potent Growth

Dental cementum contains unique molecules that regulate the mineralization process in vitro and in vivo, such as cementum protein 1 (CEMP1). This protein possesses amino acid sequence motifs like the human recombinant CEMP1 with biological activity. This novel cementum protein 1-derived peptide (CEMP1-p3, from the CEMP1’s N-terminal domain: (QPLPKGCAAVKAEVGIPAPH), consists of 20 amino acids. Hydroxyapatite (HA) crystals could be obtained through the combination of the amorphous precursor phase and macromolecules such as proteins and peptides. We used a simple method to synthesize peptide/hydroxyapatite nanocomposites using OCP and CEMP1-p3. The characterization of the crystals through scanning electron microscopy (SEM), powder X-ray diffraction (XRD), high--resolution transmission electron microscopy (HRTEM), and Raman spectroscopy revealed that CEMP1-p3 transformed OCP into hydroxyapatite (HA) under constant ionic strength and in a buffered solution. CEMP1-p3 binds and highly adsorbs to OCP and is a potent growth stimulator of OCP crystals. CEMP1-p3 fosters the transformation of OCP into HA crystals with crystalline planes (300) and (004) that correspond to the cell of hexagonal HA. Octacalcium phosphate crystals treated with CEMP1-p3 grown in simulated physiological buffer acquired hexagonal arrangement corresponding to HA. These findings provide new insights into the potential application of CEMP1-p3 on possible biomimetic approaches to generate materials for the repair and regeneration of mineralized tissues, or restorative materials in the orthopedic field.

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Multimodal imaging reveals human cholinergic system functional and structural integrity in vivo

Alzheimer s & Dementia ◽

10.1002/alz.040763 ◽

2020 ◽

Vol 16 (S5) ◽

Author(s):

Milan Nemy ◽

Michel Grothe ◽

Jose Barroso ◽

Stefan J. Teipel ◽

Eric Westman ◽

...

Keyword(s):

Cholinergic System ◽

Multimodal Imaging ◽

Structural Integrity

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Beyond radiation therapy: photodynamic therapy maintains structural integrity of irradiated healthy and metastatically involved vertebrae in a pre-clinical in vivo model

Breast Cancer Research and Treatment ◽

10.1007/s10549-012-2146-x ◽

2012 ◽

Vol 135 (2) ◽

pp. 391-401 ◽

Cited By ~ 11

Author(s):

Victor C. K. Lo ◽

Margarete K. Akens ◽

Sara Moore ◽

Albert J. M. Yee ◽

Brian C. Wilson ◽

...

Keyword(s):

Radiation Therapy ◽

Photodynamic Therapy ◽

Structural Integrity ◽

In Vivo Model

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A novel design of HA-coated nanoparticles co-encapsulating plasmid METase and 5-Fu shows enhanced application in targeting gastric cancer stem cells

Biological Chemistry ◽

10.1515/hsz-2017-0208 ◽

2018 ◽

Vol 399 (3) ◽

pp. 293-303 ◽

Cited By ~ 3

Author(s):

Weifeng Yang ◽

Houting Zhang ◽

Lin Xin

Keyword(s):

Gastric Cancer ◽

Tumor Growth ◽

Precipitation Method ◽

Inhibition Effect ◽

Coated Nanoparticles ◽

Transmission Electron ◽

Targeted Drug ◽

Gastric Cancer Stem Cells ◽

Novel Design

AbstractNanoparticles (NPs) are recognized as an attractive vehicles for cancer treatment due to their targeted drug release. Gastric cancer is an important killer disease, and its therapy methods still need improvement. The NPs were prepared using a precipitation method, and were evaluated using transmission electron microscopy (TEM). MTT and Transwell assays were used to determine cell viability and apoptosis.In vivoexperiments were performed to validate the effects of NPs on tumor growth. Methioninase (METase)/5-Fu co-encaspulated NPs showed highest ζ size and lowest ζ potential than other NPs. The migration and tumorsphere formation ability of CD44(+) was stronger than CD44(−). The effects of METase/5-Fu co-encaspulated NPs on inhibition cell growth was stronger than that of 5-Fu encaspulated NPs, while HA coated NPs showed significant target ability than that NPs without HA. METase supplementation promoted the inhibition effect of 5-Fu on thymidylate synthetase (TS), as well as cell apoptosis. Thein vivoexperiments demonstrated that HA coated NPs significantly inhibited tumor growth. It was concluded that HA-coated NPs enhance the target ability, while METase/5-Fu co-encaspulated NPs promote the inhibition effects on tumor growth in gastric cancer.

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Plumericin Protects against Experimental Inflammatory Bowel Disease by Restoring Intestinal Barrier Function and Reducing Apoptosis

Biomedicines ◽

10.3390/biomedicines9010067 ◽

2021 ◽

Vol 9 (1) ◽

pp. 67 ◽

Cited By ~ 1

Author(s):

Shara Francesca Rapa ◽

Rosanna Di Paola ◽

Marika Cordaro ◽

Rosalba Siracusa ◽

Ramona D’Amico ◽

...

Keyword(s):

Barrier Function ◽

Structural Integrity ◽

Intestinal Barrier ◽

Intestinal Barrier Function ◽

Epithelial Barrier ◽

Intestinal Epithelial ◽

Intestinal Epithelial Barrier ◽

Bowel Diseases ◽

Inflammatory Bowel

Intestinal epithelial barrier impairment plays a key pathogenic role in inflammatory bowel diseases (IBDs). In particular, together with oxidative stress, intestinal epithelial barrier alteration is considered as upstream event in ulcerative colitis (UC). In order to identify new products of natural origin with a potential activity for UC treatment, this study evaluated the effects of plumericin, a spirolactone iridoid, present as one of the main bioactive components in the bark of Himatanthus sucuuba (Woodson). Plumericin was evaluated for its ability to improve barrier function and to reduce apoptotic parameters during inflammation, both in intestinal epithelial cells (IEC-6), and in an animal experimental model of 2, 4, 6-dinitrobenzene sulfonic acid (DNBS)-induced colitis. Our results indicated that plumericin increased the expression of adhesion molecules, enhanced IEC-6 cells actin cytoskeleton rearrangement, and promoted their motility. Moreover, plumericin reduced apoptotic parameters in IEC-6. These results were confirmed in vivo. Plumericin reduced the activity of myeloperoxidase, inhibited the expression of ICAM-1, P-selectin, and the formation of PAR, and reduced apoptosis parameters in mice colitis induced by DNBS. These results support a pharmacological potential of plumericin in the treatment of UC, due to its ability to improve the structural integrity of the intestinal epithelium and its barrier function.

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