Influence of Elongation of Paclitaxel-Eluting Electrospun-Produced Stent Coating on Paclitaxel Release and Transport through the Arterial Wall after Stenting.

It was previously shown that polycaprolactone (PCL)-based electrospun-produced paclitaxel (PTX)-enriched matrices exhibit long-term drug release kinetics and can be used as coatings for drug-eluting stents (DES). The installation of vascular stents involves a twofold increase in stent diameter and, therefore, an elongation of the matrices covering the stents, as well as the arterial wall in a stented area. We studied the influence of matrix elongation on its structure and PTX release using three different electrospun-produced matrices. The data obtained demonstrate that matrix elongation during stent installation does not lead to fiber breaks and does not interfere with the kinetics of PTX release. To study PTX diffusion through the expanded artery wall, stents coated with 5%PCL/10%HSA/3%DMSO/PTX and containing tritium-labeled PTX were installed into the freshly obtained iliac artery of a rabbit. The PTX passing through the artery wall was quantified using a scintillator ß-counter. The artery retained the PTX and decreased its release from the coating. The retention of PTX by the arterial wall was more efficient when incubated in blood plasma in comparison with PBS. The retention/accumulation of PTX by the arterial wall provides a prolonged drug release and allows for the reduction in the dose of the drugs in electrospun-produced stent coatings.

Vascular Stents Coated with Electrospun Drug-Eluting Material: Functioning in Rabbit Iliac Artery.

A stenting procedure aimed at blood flow restoration in stenosed arteries significantly improves the efficiency of vascular surgery. However, the current challenge is to prevent neointimal growth, which reduces the vessel lumen, in the stented segments in the long run. We tested in vivo drug-eluting coating applied by electrospinning to metal vascular stents to inhibit the overgrowth of neointimal cells via both the drug release and mechanical support of the vascular wall. The blend of polycaprolactone with human serum albumin and paclitaxel was used for stent coating by electrospinning. The drug-eluting stents (DESs) were placed using a balloon catheter to the rabbit common iliac artery for 1, 3, and 6 months. The blood flow rate was ultrasonically determined in vivo. After explantation, the stented arterial segment was visually and histologically examined. Any undesirable biological responses (rejection or hemodynamically significant stenosis) were unobservable in the experimental groups. DESs were less traumatic and induced weaker neointimal growth; over six months, the blood flow increased by 37% versus bare-metal stents, where it increased by at least double the rate. Thus, electrospun-coated DESs demonstrate considerable advantages over the bare-metal variants.

Carotid Endarterectomy with Autoarterial Remodeling of Bifurcation of the Common Carotid Artery and Carotid Endarterectomy with Patch Closure: Comparison of Methods.

BACKGROUND: The objectives of our research were to identify whether the new method of carotid endarterectomy (CEA) with autoarterial remodeling of bifurcation of the common carotid artery (ARBCCA) influences daily parameters of blood pressure and heart rate (HR) while monitoring them on a daily basis and to assess the efficacy of the suggested method. MATERIALS AND METHODS: It is a prospective randomized comparative study. The first group (n = 100) included patients that underwent ARBCCA, the second group (n = 100) included patients that underwent "classic" CEA with xenopericardial patch closure. Diurnal Holter recording of blood pressure and (HR) was performed before and after the surgical treatment in both groups. RESULTS: Surgical treatment in both groups leads to an increase of HR, arterial hypertension time index by systolic blood pressure, and arterial hypertension time index by diastolic arterial blood pressure. The damage of carotid artery bulb increases sympathetic innervation and causes dysregulation of the baroreceptor mechanism. CONCLUSIONS: In our study, we did not reveal a significant difference in the incidence of postoperative hypertension and the dependence of HR on the choice of surgical technique. Thus, the proposed ARBCCA method does not lead to an increased risk of pre-existing arterial hypertension development. A significant difference is found out on the parameter of the clamping time of carotid arteries in favor to ARBCCA group. Another advantage of the suggested technique is the number of restenosis greater than 50% during the 2-year follow-up (4 [4%] cases (ARBCCA group) versus 12 [12%] cases ["classic" CEA], respectively, P = .037).

Electrospun Produced 3D Matrices for Covering of Vascular Stents: Paclitaxel Release Depending on Fiber Structure and Composition of the External Environment.

Paclitaxel is a natural, highly lipophilic anti proliferative drug widely used in medicine. We have studied the release of tritium-labeled paclitaxel (³H-PTX) from matrices destined for the coating of vascular stents and produced by the electrospinning method from the solutions of polycaprolactone (PCL) with paclitaxel (PTX) in hexafluoisopropanol (HFIP) and/or solutions of PCL with PTX and human serum albumin (HSA) in HFIP or HIFP-dimethyl sulphoxide (DMSO) blend. The release of PTX has been shown to depend on the composition of electrospinning solution, as well as the surrounding medium, particularly the concentration of free PTX and PTX-binding biomolecules present in human serum. It was shown that 3D matrices can completely release PTX without weight loss. Two-phase PTX release from optimized 3D matrices was obtained: ~27% of PTX was released in the first day, another 8% were released over the next 26 days. Wherein ~2.8%, ~2.3%, and ~0.25% of PTX was released on day 3, 9, and 27, respectively. Considering PTX toxicity, the rate of its diffusion through the arterial wall, and the data obtained the minimum cytostatic dose of the drug in the arterial wall will be maintained for at least three months.

Minimal standard terminology for gastrointestinal endoscopy - MST 3.0.

Standardization of the language of gastrointestinal endoscopy is becoming increasingly important on account of international collaboration, standardized documentation requirements, and computer-based reporting. Version 1 of the Minimal Standard Terminology (MST) was devised to facilitate this development, and, through broad international collaboration, the document was developed and tested further to produce version 2.0, published in 2000. The document forms the basis for computer software by offering standard minimal lists of terms to be used in the structured documentation of endoscopic findings. The ownership of the MST has been transferred to the World Organisation of Digestive Endoscopy (OMED) and in this context, a new revision of the MST document is now in place. Version 3.0 of the terminology includes terms for endoscopic ultrasound (EUS) and enteroscopy, as well as for adverse event reporting. In addition, acknowledged scoring systems have been included for specific findings, and some structural enhancements have been implemented. The entire document is freely available for noncommercial use from www.omed.org.