scholarly journals In Vitro Measurement of Tissue Integrity during Saccular Aneurysm Embolizations for Simulator-Based Training

2012 ◽  
Vol 18 (4) ◽  
pp. 401-412
Author(s):  
C. Tercero ◽  
S. Ikeda ◽  
K. Ooe ◽  
T. Fukuda ◽  
F. Arai ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Saccular Aneurysm ◽  
Release Mechanism ◽  
Tissue Integrity ◽  
Treatment Techniques ◽  
Tissue Manipulation ◽  
Platinum Coil ◽  
Stress Variations ◽  
Micro Catheter

In the domain of endovascular neurosurgery, the measurement of tissue integrity is needed for simulator-based training and for the development of new intravascular instruments and treatment techniques. In vitro evaluation of tissue manipulation can be achieved using photoelastic stress analysis and vasculature modeling with photoelastic materials. In this research we constructed two types of vasculature models of saccular aneurysms for differentiation of embolization techniques according to the respect for tissue integrity measurements based on the stress within the blood vessel model wall. In an aneurysm model with 5 mm dome diameter, embolization using MicroPlex 10 (Complex 1D, with 4 mm diameter loops), a maximum area of 3.97 mm2 with stress above 1 kPa was measured. This area increased to 5.50 mm2 when the dome was touched deliberately with the release mechanism of the coil, and to 4.87 mm2 for an embolization using Micrusphere, (Spherical 18 Platinum Coil). In a similar way trans-cell stent-assisted coil embolization was also compared to human blood pressure simulation using a model of a wide-necked saccular aneurysm with 7 mm diameter. The area with stress above 1kPa was below 1 mm2 for the pressure simulation and maximized at 3.79 mm2 during the trans-cell insertion of the micro-catheter and at 8.92 mm2 during the embolization. The presented results show that this measurement system is useful for identifying techniques compromising tissue integrity, comparing and studying coils and embolization techniques for a specific vasculature morphology and comparing their natural stress variations such as that produced by blood pressure.

The Involvement of Platelets and the Coronary Vasculature in Collagen-Induced Sudden Death in Rabbits

1985 ◽  
Vol 53 (01) ◽  
pp. 070-074 ◽  
Author(s):  
G Mallarkey ◽  
G M Smith
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Platelet Count ◽  
Sudden Death ◽  
Myocardial Ischaemia ◽  
Plasma Levels ◽  
Sodium Citrate ◽  
Plasma Samples ◽  
Calcium Entry Blockers

SummaryThe mechanism of collagen-induced sudden death in rabbits was studied by measuring blood pressure (BP), heart rate, ECG, the continuous platelet count and the plasma levels of thromboxane B2 (TxB2) and 6-keto prostaglandin Fia (6-keto PGF1α). Death was preceded by myocardial ischaemia and a sharp fall in BP which occurred before any fall in platelet count was observed. The calcium entry blockers (CEBs), verapamil, nifedipine and PY 108-068 protected the rabbits from sudden death without any significant effect on the decrease in the platelet count or increase in plasma TxB2 levels. 6-keto PGF1α could not be detected in any plasma samples. Indomethacin and tri-sodium citrate also protected the rabbits but significantly reduced the fall in platelet count and plasma TxB2. In vitro studies on isolated aortae indicated that verapamil non-specifically inhibited vasoconstriction induced by KC1, adrenaline and U46619 (a thromboxane agonist). It is concluded that CEBs physiologically antagonize the vasoconstricting actions of platelet-derived substances and that it is coronary vasoconstriction that is primarily the cause of death.

Formulation and In Vivo Evaluation of Mucoadhesive Micro-spheres of Rebamipide, a Mucoprotective Drug for GIT Disorders

2018 ◽  
Vol 11 (3) ◽  
pp. 4089-4097
Author(s):  
Bhikshapathi D. V. R. N. ◽  
Kanteepan P
Keyword(s):  
Drug Release ◽  
Entrapment Efficiency ◽  
In Vivo Studies ◽  
Amino Acid Derivative ◽  
Release Mechanism ◽  
In Vivo Evaluation ◽  
In Vitro Drug Release ◽  
Percentage Yield

Rebamipide, an amino acid derivative of 2-(1H)-quinolinone, is used for mucosal protection, healing of gastroduodenal ulcers, and treatment of gastritis. The current research study aimed to develop novel gastro-retentive mucoadhesive microspheres of rebamipide using ionotropic gelation technique. Studies of micromeritic properties confirmed that microspheres were free flowing with good packability. The in vitro drug release showed the sustained release of rebamipide up to 99.23 ± 0.13% within 12 h whereas marketed product displayed the drug release of 95.15 ± 0.23% within 1 h. The release mechanism from microspheres followed the zero-order and Korsmeyer-Peppas (R2 = 0.915, 0.969), respectively. The optimized M12 formulation displayed optimum features, such as entrapment efficiency 97%, particle size 61.94 ± 0.11 µm, percentage yield 98%, swelling index 95% and mucoadhesiveness was 97%. FTIR studies revealed no major incompatibility between drug and excipients. SEM confirmed the particles were of spherical in shape. Optimized formulation (M12) were stable at 40°C ± 2°C/75% RH ± 5% RH for 6 months. In vivo studies were performed and kinetic parameters like Cmax, Tmax, AUC0-t, AUC0-∞, t1/2, and Kel  were calculated. The marketed product Cmax (3.15 ± 0.05 ng/mL) was higher than optimized formulation (2.58 ± 0.03 ng/mL). The optimized formulation AUC0-t (15.25 ± 1.14 ng.hr/mL), AUC0-∞ (19.42 ± 1.24 ng.hr/mL) was significantly higher than that of marketed product AUC0-t (10.21 ± 1.26 ng.hr/mL) and AUC0-∞ (13.15 ± 0.05 ng.hr/mL). These results indicate an optimized formulation bioavailability of 2.5-fold greater than marketed product.  

The Development of Pemetrexed Diacid-Loaded Gelatin-Cloisite 30B (MMT) Nanocomposite for Improved Oral Efficacy Against Cancer: Characterization, In-Vitro and Ex-Vivo Assessment

2020 ◽  
Vol 17 (3) ◽  
pp. 246-256
Author(s):  
Kriti Soni ◽  
Ali Mujtaba ◽  
Md. Habban Akhter ◽  
Kanchan Kohli
Keyword(s):  
Drug Release ◽  
Oral Delivery ◽  
Ex Vivo ◽  
Confocal Laser ◽  
Release Mechanism ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Cloisite 30B ◽  
Ft Ir

Aim: The intention of this investigation was to develop Pemetrexed Diacid (PTX)-loaded gelatine-cloisite 30B (MMT) nanocomposite for the potential oral delivery of PTX and the in vitro, and ex vivo assessment. Background: Gelatin/Cloisite 30 B (MMT) nanocomposites were prepared by blending gelatin with MMT in aqueous solution. Methods: PTX was incorporated into the nanocomposite preparation. The nanocomposites were investigated by Fourier Transmission Infra Red Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) X-Ray Diffraction (XRD) and Confocal Laser Microscopy (CLSM). FT-IR of nanocomposite showed the disappearance of all major peaks which corroborated the formation of nanocomposites. The nanocomposites were found to have a particle size of 121.9 ± 1.85 nm and zeta potential -12.1 ± 0.63 mV. DSC thermogram of drug loaded nanocomposites indicated peak at 117.165 oC and 205.816 oC, which clearly revealed that the drug has been incorporated into the nanocomposite because of cross-linking of cloisite 30 B and gelatin in the presence of glutaraldehyde. Results: SEM images of gelatin show a network like structure which disappears in the nanocomposite. The kinetics of the drug release was studied in order to ascertain the type of release mechanism. The drug release from nanocomposites was in a controlled manner, followed by first-order kinetics and the drug release mechanism was found to be of Fickian type. Conclusion: Ex vivo gut permeation studies revealed 4 times enhancement in the permeation of drug present in the nanocomposite as compared to plain drug solution and were further affirmed by CLSM. Thus, gelatin/(MMT) nanocomposite could be promising for the oral delivery of PTX in cancer therapy and future prospects for the industrial pharmacy.

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Antihypertensive Activity ◽  
Computer Assisted ◽  
Hypertensive Rats ◽  
Vasorelaxant Effect ◽  
Arterial Blood

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

Vasorelaxant and Antihypertensive Effects of Mentha pulegium L. in Rats: An in vitro and in vivo Approach

2020 ◽  
Vol 20 ◽  
Author(s):  
Mohammed Ajebli ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Acute Experiment ◽  
Antihypertensive Activity ◽  
Mentha Pulegium ◽  
In Vitro Experiment ◽  
Arterial Blood ◽  
Dose Dependent ◽  
Ca2 Channels

Aims and objective: The aim of the study was to investigate the effect of aqueous aerial part extract of Mentha pulegium L. (Pennyrile) (MPAE) on arterial pressure parameters in rats. Background: Mentha pulegium is a medicinal plant used to treat hypertension in Morocco. Material and methods: In the current study, MPAE was prepared and its antihypertensive activity was pharmacologically investigated. L-NAME-hypertensive and normotensive rats have received orally MPAE (180 and 300 mg/kg) during six hours for the acute experiment and during seven days for the sub-chronic treatment. Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were evaluated. While, in the in vitro experiment, isolated denuded and intact thoracic aortic rings were suspended in a tissue bath system and the tension changes were recorded. Results: A fall in blood pressure was observed in L-NAME-induced hypertensive treated with MPAE. The extract also produced a dose-dependent relaxation of aorta pre-contracted with NE and KCl. The study showed that the vasorelaxant ability of MPAE seems to be exerted through the blockage of extracellular Ca2+ entry. Conclusion: The results demonstrate that the extract of pennyrile exhibits antihypertensive activity. In addition, the effect may be, at least in part, due to dilation of blood vessels via blockage of Ca2+ channels.

Methylprednisolone on circulating eicosanoids and vasomotor tone after endotoxin

1986 ◽  
Vol 61 (1) ◽  
pp. 185-191 ◽  
Author(s):  
C. A. Hales ◽  
R. D. Brandstetter ◽  
C. F. Neely ◽  
M. B. Peterson ◽  
D. Kong ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Systemic Blood Pressure ◽  
Physiological Effect ◽  
High Dose ◽  
Systemic Blood ◽  
Eicosanoid Production ◽  
Circulating Levels

Acute pulmonary and systemic vasomotor changes induced by endotoxin in dogs have been related, at least in part, to the production of eicosanoids such as the vasoconstrictor thromboxane and the vasodilator prostacyclin. Steroids in high doses, in vitro, inhibit activation of phospholipase A2 and prevent fatty acid release from cell membranes to enter the arachidonic acid cascade. We, therefore, administered methylprednisolone (40 mg/kg) to dogs to see if eicosanoid production and the ensuing vasomotor changes could be prevented after administration of 150 micrograms/kg of endotoxin. The stable metabolites of thromboxane B2 (TxB2) and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) were measured by radioimmunoassay. Methylprednisolone by itself did not alter circulating eicosanoids but when given 2.5 h before endotoxin not only failed to inhibit endotoxin-induced eicosanoid production but actually resulted in higher circulating levels of 6-keto-PGF1 alpha (P less than 0.05) compared with animals receiving endotoxin alone. Indomethacin prevented the steroid-enhanced concentrations of 6-keto-PGF1 alpha after endotoxin and prevented the greater fall (P less than 0.05) in systemic blood pressure and systemic vascular resistance with steroid plus endotoxin than occurred with endotoxin alone. Administration of methylprednisolone immediately before endotoxin resulted in enhanced levels (P less than 0.05) of both TxB2 and 6-keto-PGF1 alpha but with a fall in systemic blood pressure and vascular resistance similar to the animals pretreated by 2.5 h. In contrast to the early steroid group in which all of the hypotensive effect was due to eicosanoids, in the latter group steroids had an additional nonspecific effect. Thus, in vivo, high-dose steroids did not prevent endotoxin-induced increases in eicosanoids but actually increased circulating levels of TxB2 and 6-keto-PGF1 alpha with a physiological effect favoring vasodilation.

scholarly journals Is a diluted seawater-based solution safe and effective on human nasal epithelium?

2021 ◽  
Author(s):  
Song Huang ◽  
Samuel Constant ◽  
Barbara De Servi ◽  
Marisa Meloni ◽  
Amina Saaid ◽  
...  
Keyword(s):  
Wound Repair ◽  
Wound Closure ◽  
Isotonic Saline ◽  
Nasal Epithelium ◽  
Mucin Secretion ◽  
Nasal Irrigation ◽  
Tissue Integrity ◽  
Human Nasal Epithelium ◽  
Pre Treatment

Abstract Purpose Nasal irrigation is an effective method for alleviating several nasal symptoms and regular seawater-based nasal irrigation is useful for maintaining nasal hygiene which is essential for appropriate functioning of the nose and for preventing airborne particles including some pollutants, pathogens, and allergens from moving further in the respiratory system. However, safety studies on seawater-based nasal irrigation are scarce. In this study, the safety and efficacy of a diluted isotonic seawater solution (Stérimar Nasal Hygiene, SNH) in maintaining nasal homeostasis were evaluated in vitro. Methods Safety was assessed by measuring tissue integrity via transepithelial electrical resistance (TEER). Efficacy was measured by mucociliary clearance (MCC), mucin secretion, and tissue re-epithelization (wound repair) assays. All assays were performed using a 3D reconstituted human nasal epithelium model. Results In SNH-treated tissues, TEER values were statistically significantly lower than the untreated tissues; however, the values were above the tissue integrity limit. SNH treatment significantly increased MCC (88 vs. 36 µm/s, p < 0.001) and mucin secretion (1717 vs. 1280 µg/ml, p < 0.001) as compared to untreated cultures. Faster wound closure profile was noted upon pre-SNH treatment as compared to classical isotonic saline solution pre-treatment (90.5 vs. 50.7% wound closure 22 h after wound generation). Conclusion SNH did not compromise the integrity of the nasal epithelium in vitro. Furthermore, SNH was effective for removal of foreign particles through MCC increase and for enhancing wound repair on nasal mucosa.

scholarly journals Production and Characterization of Chitosan–Polyanion Nanoparticles by Polyelectrolyte Complexation Assisted by High-Intensity Sonication for the Modified Release of Methotrexate

2020 ◽  
Vol 13 (1) ◽  
pp. 11 ◽  
Author(s):  
Yhors Ciro ◽  
John Rojas ◽  
Maria Alhajj ◽  
Gustavo Carabali ◽  
Constain Salamanca
Keyword(s):  
Zeta Potential ◽  
Maleic Acid ◽  
High Intensity ◽  
Physical Stability ◽  
Release Mechanism ◽  
Diffusion Controlled ◽  
Polyelectrolyte Complexation ◽  
Anticancer Treatment ◽  
Particle Parameters

A promising strategy to improve the effectivity of anticancer treatment and decrease its side effects is to modulate drug release by using nanoparticulates (NPs) as carriers. In this study, methotrexate-loaded chitosan–polyanion nanoparticles were produced by polyelectrolyte complexation assisted by high-intensity sonication, using several anionic polymers, such as the sodium and potassium salts of poly(maleic acid-alt-ethylene) and poly(maleic acid-alt-octadecene), here named PAM-2 and PAM-18, respectively. Such NPs were analyzed and characterized according to particle size, polydispersity index, zeta potential and encapsulation efficiency. Likewise, their physical stability was tested at 4 °C and 40 °C in order to evaluate any change in the previously mentioned particle parameters. The in vitro methotrexate release was assessed at a pH of 7.4, which simulated physiological conditions, and the data were fitted to the heuristic models of order one, Higuchi, Peppas–Sahlin and Korsmeyer–Peppas. The results revealed that most of the MTX-chitosan–polyanion NPs have positive zeta potential values, sizes <280 nm and monodisperse populations, except for the NPs formed with PAM-18 polyanions. Further, the NPs showed adequate physical stability, preventing NP–NP aggregation. Likewise, these carriers modified the MTX release by an anomalous mechanism, where the NPs formed with PAM-2 polymer led to a release mechanism controlled by diffusion and relaxation, whereas the NPs formed with PAM-18 led to a mainly diffusion-controlled release mechanism.

scholarly journals A Novel Design of Tri-Layer Membrane with Controlled Delivery of Paclitaxel and Anti-Biofilm Effect for Biliary Stent Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 486
Author(s):  
Abdelrahman I. Rezk ◽  
Jeesoo Park ◽  
Joon Yeon Moon ◽  
Sunny Lee ◽  
Chan Hee Park ◽  
...  
Keyword(s):  
Sustained Release ◽  
Antibacterial Effect ◽  
Release Profile ◽  
Biliary Stent ◽  
Fickian Diffusion ◽  
Release Mechanism ◽  
Dual Function ◽  
Electrospinning Technique ◽  
Layer Membrane

Here, we developed a novel biliary stent coating material that is composed of tri-layer membrane with dual function of sustained release of paclitaxel (PTX) anticancer drug and antibacterial effect. The advantages of using electrospinning technique were considered for the even distribution of PTX and controlled release profile from the nanofiber mat. Furthermore, film cast method was utilized to fabricate AgNPs-immobilized PU film to direct the release towards the tumor site and suppress the biofilm formation. The in vitro antibacterial test conducted against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria species showed excellent antibacterial effect. The in vitro drug release study confirmed the sustained release of PTX from the tri-layer membrane and the release profile fitted first order with correlation coefficient of R2 = 0.98. Furthermore, the release mechanism was studied using Korsmeyer–Peppas model, revealing that the release mechanism follows Fickian diffusion. Based on the results, this novel tri-layer membrane shows curative potential in clinical development.

scholarly journals In Vitro Drug Release, Permeability, and Structural Test of Ciprofloxacin-Loaded Nanofibers

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 556
Author(s):  
Luca Éva Uhljar ◽  
Sheng Yuan Kan ◽  
Norbert Radacsi ◽  
Vasileios Koutsos ◽  
Piroska Szabó-Révész ◽  
...  
Keyword(s):  
Amorphous State ◽  
Physical Mixture ◽  
Water Soluble ◽  
Vinyl Pyrrolidone ◽  
Amorphous Solid Dispersion ◽  
Release Mechanism ◽  
Dissolution Studies ◽  
In Vitro Diffusion ◽  
Poly Vinyl Pyrrolidone

Nanofibers of the poorly water-soluble antibiotic ciprofloxacin (CIP) were fabricated in the form of an amorphous solid dispersion by using poly(vinyl pyrrolidone) as a polymer matrix, by the low-cost electrospinning method. The solubility of the nanofibers as well as their in vitro diffusion were remarkably higher than those of the CIP powder or the physical mixture of the two components. The fiber size and morphology were optimized, and it was found that the addition of the CIP to the electrospinning solution decreased the nanofiber diameter, leading to an increased specific surface area. Structural characterization confirmed the interactions between the drug and the polymer and the amorphous state of CIP inside the nanofibers. Since the solubility of CIP is pH-dependent, the in vitro solubility and dissolution studies were executed at different pH levels. The nanofiber sample with the finest morphology demonstrated a significant increase in solubility both in water and pH 7.4 buffer. Single medium and two-stage biorelevant dissolution studies were performed, and the release mechanism was described by mathematical models. Besides, in vitro diffusion from pH 6.8 to pH 7.4 notably increased when compared with the pure drug and physical mixture. Ciprofloxacin-loaded poly(vinyl pyrrolidone) (PVP) nanofibers can be considered as fast-dissolving formulations with improved physicochemical properties.

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