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International Journal of Nanomedicine 2022Biopiezoelectric materials have good biocompatibility and excellent piezoelectric properties, and they can generate local currents in vivo to restore the physiological...
PURPOSE
Biopiezoelectric materials have good biocompatibility and excellent piezoelectric properties, and they can generate local currents in vivo to restore the physiological electrical microenvironment of the defect and promote bone regeneration. Previous studies of guided bone regeneration membranes have rarely addressed the point of restoring it, so this study prepared a Barium titanate/Polylactic acid (BT/PLA) piezoelectric composite membrane and investigated its bone-formation, with a view to providing an experimental basis for clinical studies of guided bone tissue regeneration membranes.
METHODS
BT/PLA composite membranes with different BT ratio were prepared by solution casting method, and piezoelectric properties were performed after corona polarization treatment. The optimal BT ratio was selected and then subjected to in vitro cytological experiments and in vivo osteogenic studies in rats. The effects on adhesion, proliferation and osteogenic differentiation of the pre-osteoblastic cell line (MC3T3-E1) were investigated. The effect of composite membranes on bone repair of cranial defects in rats was investigated after 4 and 12 weeks.
RESULTS
The highest piezoelectric coefficient d33 were obtained when the BT content was 20%, reaching (7.03 ± 0.26) pC/N. The value could still be maintained at (4.47±0.17) pC/N after 12 weeks, meeting the piezoelectric constant range of bone. In vitro, the MC3T3-E1 cells showed better adhesion and proliferative activity in the group of polarized 20%BT. The highest alkaline phosphatase (ALP) content was observed in cells of this group. In vivo, it promoted rapid bone regeneration. At 4 weeks postoperatively, new bone formation was evident at the edges of the defect, with extensive marrow cavity formation; after 12 weeks, the defect was essentially completely closed, with density approximating normal bone tissue and significant mineralization.
CONCLUSION
The BT/PLA piezoelectric composite membrane has good osteogenic properties and provides a new idea for guiding the research of membrane materials for bone tissue regeneration.
Topics: Alkaline Phosphatase; Animals; Barium; Barium Compounds; Biocompatible Materials; Bone Regeneration; Bone and Bones; Cell Differentiation; Osteogenesis; Polyesters; Rats; Tissue Scaffolds; Titanium
PubMed: 36160471
DOI: 10.2147/IJN.S378422 -
Journal of Speech, Language, and... Oct 2022The elements of impaired swallowing biomechanics are visually assessed and scored by clinicians using a standardized and validated tool for assessing type and severity...
PURPOSE
The elements of impaired swallowing biomechanics are visually assessed and scored by clinicians using a standardized and validated tool for assessing type and severity of physiological impairments using the Modified Barium Swallow Impairment Profile (MBSImP). However, the functional anatomical correlates that underly noted impairments using MBSImP scoring have not been measured. The purpose of this study was to determine whether differences in MBSImP component scores represent differences in underlying swallowing mechanics as measured by computational analysis of swallowing mechanics (CASM) to better define underlying mechanisms of impairment.
METHOD
A retrospective analysis of modified barium swallow studies from physician-referred adult patients with dysphagia was scored using the MBSImP for laryngeal elevation, anterior hyoid excursion, epiglottic movement, pharyngoesophageal segment opening, and tongue base retraction. A canonical variate analysis (CVA) was performed to determine the movement of anatomical landmarks associated with MBSImP component scores using the CASM method. Mahalanobis distances () were then used to detect differences among MBSImP scores for each component assessed.
RESULTS
CVA showed significant differences ( < .0001) in Mahalanobis distance ( > 1) between MBSImP component scores of 0-1, 0-2, 0-3, or 0-4, as applicable, depending on the component. Discriminant function analyses revealed concomitant increase/worsening in MBSImP score with changes in anatomical positioning of structures.
CONCLUSIONS
Ratings of swallowing impairment and physiology using the MBSImP have distinct biomechanical correlates with anatomical movements of swallowing. These data further demonstrate how swallowing mechanics are highly interrelated. Understanding these linkages between anatomical and physiological movement within impaired swallowing biomechanics is essential in more specific characterization and treatment of dysphagia.
SUPPLEMENTAL MATERIAL
https://doi.org/10.23641/asha.20816788.
Topics: Adult; Barium; Biomechanical Phenomena; Deglutition; Deglutition Disorders; Humans; Retrospective Studies
PubMed: 36075206
DOI: 10.1044/2022_JSLHR-22-00047 -
The Journal of Physiology Apr 2007Electrophysiological and molecular characteristics of voltage-dependent calcium (Ca(2+)) channels were studied using whole-cell patch clamp, polymerase chain reaction...
Electrophysiological and molecular characteristics of voltage-dependent calcium (Ca(2+)) channels were studied using whole-cell patch clamp, polymerase chain reaction and Western blotting in smooth muscle cells freshly isolated from dog basilar artery. Inward currents evoked by depolarizing steps from a holding potential of -50 or -90 mV in 10 mm barium consisted of low- (LVA) and high-voltage activated (HVA) components. LVA current comprised more than half of total current in 24 (12%) of 203 cells and less than 10% of total current in 52 (26%) cells. The remaining cells (127 cells, 62%) had LVA currents between one tenth and one half of total current. LVA current was rapidly inactivating, slowly deactivating, inhibited by high doses of nimodipine and mibefradil (> 0.3 microM), not affected by omega-agatoxin GVIA (gamma100 nM), omega-conotoxin IVA (1 microM) or SNX-482 (200 nM) and probably carried by T-type Ca(2+) channels based on the presence of messenger ribonucleic acid (mRNA) and protein for Ca(v3.1) and Ca(v3.3) alpha(1) subunits of these channels. LVA currents exhibited window current with a maximum of 13% of the LVA current at -37.4 mV. HVA current was slowly inactivating and rapidly deactivating. It was inhibited by nimodipine (IC(50) = 0.018 microM), mibefradil (IC(50) = 0.39 microM) and omega-conotoxin IV (1 microM). Smooth muscle cells also contained mRNA and protein for L- (Ca(v1.2) and Ca(v1.3)), N- (Ca(v2.2)) and T-type (Ca(v3.1) and Ca(v3.3)) alpha(1) Ca(2+) channel subunits. Confocal microscopy showed Ca(v1.2) and Ca(v1.3) (L-type), Ca(v2.2) (N-type) and Ca(v3.1) and Ca(v3.3) (T-type) protein in smooth muscle cells. Relaxation of intact arteries under isometric tension in vitro to nimodipine (1 microM) and mibefradil (1 microM) but not to omega-agatoxin GVIA (100 nM), omega-conotoxin IVA (1 microM) or SNX-482 (1 microM) confirmed the functional significance of L- and T-type voltage-dependent Ca(2+) channel subtypes but not N-type. These results show that dog basilar artery smooth muscle cells express functional voltage-dependent Ca(2+) channels of multiple types.
Topics: Animals; Barium; Basilar Artery; Calcium; Calcium Channels; Dogs; Immunohistochemistry; In Vitro Techniques; Myocytes, Smooth Muscle; Patch-Clamp Techniques; Time Factors
PubMed: 17185332
DOI: 10.1113/jphysiol.2006.126128 -
Acta Gastro-enterologica Belgica 2020
Topics: Barium; Endoscopy, Digestive System; Esophagus; Humans
PubMed: 33094604
DOI: No ID Found -
European Respiratory Review : An... Mar 2021https://bit.ly/2IOl7p6
https://bit.ly/2IOl7p6
Topics: Barium; Humans; Tracheoesophageal Fistula
PubMed: 33568527
DOI: 10.1183/16000617.0358-2020 -
The Tohoku Journal of Experimental... Jan 2019Esophageal achalasia is a disease characterized by the impaired esophageal peristalsis and non-relaxation of the lower esophageal sphincter muscle with unknown causes....
Esophageal achalasia is a disease characterized by the impaired esophageal peristalsis and non-relaxation of the lower esophageal sphincter muscle with unknown causes. Clinical manifestation of the disease is nonspecific (e.g., weight loss, vomiting, and persistent cough); namely, early diagnosis of the disease is often difficult. Delayed diagnosis of the disease is known to impair the patients' quality of life. Identifying the diagnostic factors that could cause diagnostic delay is needed. In this study, we collected data from 38 patients with achalasia and searched for diagnostic factors associated with delayed diagnosis (i.e., ≥ 6 months from the first hospital visit to diagnosis). The enrolled patients, diagnosed with achalasia based on esophageal manometry findings, had undergone surgical myotomy. As a result, the diagnosis of achalasia was likely to be delayed when the physician who had first contacted the patient did not perform a barium swallow test (p < 0.0001) or chest CT scan (p < 0.01) in a timely fashion. Among the patients with a delayed diagnosis (n = 15), none underwent a barium swallow test or chest CT within 6 months from their first hospital visit. The estimated sensitivities of diagnostic examinations for achalasia based on the enrolled 38 patients were higher than 80% for the barium swallow test and chest CT scan, but only 50-81% for endoscopy. To avoid the delayed diagnosis of achalasia, performing a barium swallow test or chest CT scan in a timely fashion, in addition to routine endoscopy, appears to be highly important.
Topics: Adolescent; Adult; Aged; Barium; Esophageal Achalasia; Female; Humans; Male; Middle Aged; Primary Health Care; Radiography, Thoracic; Sensitivity and Specificity; Time Factors; Tomography, X-Ray Computed
PubMed: 30662021
DOI: 10.1620/tjem.247.41 -
The Journal of Physiology Jan 19781. Intracellular injection, recording and current-passing methods were used to investigate the role of intracellular Ca in the modulation of electrical behaviour in the...
1. Intracellular injection, recording and current-passing methods were used to investigate the role of intracellular Ca in the modulation of electrical behaviour in the ciliate Paramecium caudatum.2. Injection of EGTA converted graded regenerative responses ascribed to Ca inward current to all-or-none action potentials. The EGTA injection also caused a discontinuity in the steady state I-V relations to outward current, but had little effect on hyperpolarizing current-voltage responses.3. The overshoot of the all-or-none spike produced by the EGTA-injected cell followed an approximate 29 mV increase for a tenfold increase in external Ca concentration and was independent of changes in external K and Na concentrations.4. The EGTA-induced all-or-none action potential tended to produce plateaus that could last up to 20 sec. During the plateau the membrane slowly repolarized to a critical potential, upon which repolarization occurred precipitously.5. Injection of 10(-6)M-free Ca(2+) as a Ca-EGTA buffer hyperpolarized the membrane and decreased the potential shifts to inward current pulses. These responses are consistent with an increase in K conductance.6. During EGTA plateaus reversed beating of the cilia indicated a rise in intracellular Ca, and thus an inability of the EGTA to complex the Ca as rapidly as it entered the cilia. Reversal of the motile apparatus thus appears to be activated at lower concentrations of intracellular Ca than are required to activate the inferred Ca-dependent K system.7. In uninjected cells removal of the cilia, which results in a loss of the voltage-activated Ca channels (Dunlap, 1977), or addition of extracellular Ba both tended to linearize the steady state I-V relations.8. Injections of Cs and TEA tended to linearize the steady state I-V relations, but did not result in either a conversion to an all-or-none spike or a discontinuity in the depolarizing steady-state I-V relations.9. It is concluded that in Paramecium a Ca-activated K conductance short-circuits the inward current of the regenerative Ca response, preventing all-or-none behaviour. The occurrence of plateau spikes following EGTA injection indicates that the Ca conductance inactivates very slowly in face of a maintained depolarization. Such slow Ca-inactivation is consistent with the slow relaxation of Ca-dependent ciliary reversal that occurs during maintained depolarization.10. The possibility is discussed that injection of EGTA may also enhance the Ca conductance.
Topics: Action Potentials; Animals; Barium; Calcium; Cesium; Egtazic Acid; Electric Conductivity; Membrane Potentials; Paramecium; Potassium; Tetraethylammonium Compounds
PubMed: 415134
DOI: 10.1113/jphysiol.1978.sp012171 -
The Journal of General Physiology Mar 1986K channels in the basolateral membrane of insect hindgut were studied using current fluctuation analysis and microelectrodes. Locust recta were mounted in Ussing-type... (Review)
Review
K channels in the basolateral membrane of insect hindgut were studied using current fluctuation analysis and microelectrodes. Locust recta were mounted in Ussing-type chambers containing Cl-free saline and cyclic AMP (cAMP). A transepithelial K current was induced by raising serosal [K] under short-circuit conditions. Adding Ba to the mucosal (luminal) side under these conditions had no effect; however, serosal Ba reversibly inhibited the short-circuit current (Isc), increased transepithelial resistance (Rt), and added a Lorentzian component to power density spectra of the Isc. A nonlinear relationship between corner frequency and serosal [Ba] was observed, which suggests that the rate constant for Ba association with basolateral channels increased as [Ba] was elevated. Microelectrode experiments revealed that the basolateral membrane hyperpolarized when Ba was added: this change in membrane potential could explain the nonlinearity of the 2 pi fc vs. [Ba] relationship if external Ba sensed about three-quarters of the basolateral membrane field. Conventional microelectrodes were used to determine the correspondence between transepithelially measured current noise and basolateral membrane conductance fluctuations, and ion-sensitive microelectrodes were used to measure intracellular K activity (acK). From the relationship between the net electrochemical potential for K across the basolateral membrane and the single channel current calculated from noise analysis, we estimate that the conductance of basolateral K channels is approximately 60 pS, and that there are approximately 180 million channels per square centimeter of tissue area.
Topics: Animals; Barium; Electric Conductivity; Electrochemistry; Epithelium; Grasshoppers; Intestinal Mucosa; Ion Channels; Male; Membrane Potentials; Models, Biological; Potassium
PubMed: 2420918
DOI: 10.1085/jgp.87.3.443 -
Nature Communications Apr 2018Ba proxies have been broadly used to reconstruct past oceanic export production. However, the precise mechanisms underlying barite precipitation in undersaturated...
Ba proxies have been broadly used to reconstruct past oceanic export production. However, the precise mechanisms underlying barite precipitation in undersaturated seawater are not known. The link between bacterial production and particulate Ba in the ocean suggests that bacteria may play a role. Here we show that under experimental conditions marine bacterial biofilms, particularly extracellular polymeric substances (EPS), are capable of bioaccumulating Ba, providing adequate conditions for barite precipitation. An amorphous P-rich phase is formed at the initial stages of Ba bioaccumulation, which evolves into barite crystals. This supports that in high productivity regions where large amounts of organic matter are subjected to bacterial degradation, the abundant EPS would serve to bind the necessary Ba and form nucleation sites leading to barite precipitation. This also provides new insights into barite precipitation and opens an exciting field to explore the role of EPS in mineral precipitation in the ocean.
Topics: Bacteria; Barium; Biofilms; Biopolymers; Seawater
PubMed: 29691412
DOI: 10.1038/s41467-018-04069-z -
British Medical Journal Jul 1951
Topics: Barium; Carbonates; Humans; Jurisprudence
PubMed: 14848529
DOI: No ID Found