Percutaneous laser treatment of atherosclerosis: an overview of emerging techniques

Benchmark of site- and structure-specific quantitative tissue N-glycoproteomics for discovery of potential N-glycoprotein markers: a case study of pancreatic cancer

Pancreatic cancer is a highly malignant tumor of the digestive tract that is difficult to diagnose and treat. It is more common in developed countries and has become one of the main causes of death in some countries and regions. Currently, pancreatic cancer generally has a poor prognosis, partly due to the lack of symptoms in the early stages of pancreatic cancer. Therefore, most cases are diagnosed at advanced stage. With the continuous in-depth research of glycoproteomics in precision medical diagnosis, there have been some reports on quantitative analysis of cancer-related cells, plasma or tissues to find specific biomarkers for targeted therapy. This research is based on the developed complete N-linked glycopeptide database search engine GPSeeker, combined with liquid-mass spectrometry and stable diethyl isotope labeling, providing a benchmark of site- and structure-specific quantitative tissue N-glycoproteomics for discovery of potential N-glycoprotein markers. With spectrum-level FDR ≤1%, 20,038 intact N-Glycopeptides corresponding to 4518 peptide backbones, 228 N-glycan monosaccharide compositions 1026 N-glycan putative structures, 4460 N-glycosites and 3437 intact N-glycoproteins were identified. With the criteria of ≥1.5-fold change and p value<0.05, 52 differentially expressed intact N-glycopeptides (DEGPs) were found in pancreatic cancer tussues relative to control, where 38 up-regulated and 14 down-regulated, respectively.

Photodynamic therapy: applications in atherosclerotic vascular disease with motexafin lutetium

Photodynamic therapy (PDT) has been approved as a tissue-specific light-activated cytotoxic therapy for many diseases. The ability of PDT to destroy target tissues selectively is especially appealing for atherosclerotic plaque. Biotechnology has developed a new generation of selective photosensitizers and catheter-based technological advances in light delivery have allowed the introduction of PDT into the vasculature. The largest experience to date is with motexafin lutetium (MLu, Antrin), an expanded porphyrin (texaphyrin) that accumulates in plaque. The combination of the motexafin lutetium and endovascular illumination, or Antrin phototherapy, has been shown to reduce plaque in animal models. Antrin phototherapy generates cytotoxic singlet oxygen that has been shown to induce apoptosis in macrophages and smooth muscle cells. The safety, tolerability, and preliminary efficacy of Antrin phototherapy has been assessed in a phase 1 dose-ranging clinical trial in subjects with peripheral artery disease and is currently being examined in a phase 1 study in subjects with lesions of the native coronary arteries undergoing stent implantation. The preliminary results suggest that Antrin phototherapy is safe, well tolerated, and nontraumatic.

Differential neointimal response to coronary artery injury in pigs and dogs. Implications for restenosis models

Neointimal hyperplasia occurs in the coronary arteries after percutaneous revascularization procedures and is a reparative response that frequently causes recurrent stenosis. Prior animal studies have shown that neointimal tissue thickness is proportional to the depth of arterial injury. Because animal models are increasingly used to test therapeutic strategies against restenosis, the purpose of this study was to evaluate the degree of neointimal thickening formed in the coronary arteries of pigs compared with dogs in response to severe injury. Fourteen coronary arteries in six mongrel dogs and 18 coronary arteries in nine pigs underwent severe arterial injury using tantalum metal coils delivered on oversized angioplasty balloons. Animals were killed after 4 weeks, and all coronary arteries were pressure perfusion fixed. Mean histological injury scores and neointimal thicknesses for dogs were 1.9 +/- 0.3 and 0.30 +/- 0.11, respectively, compared with 2.1 +/- 0.7 and 0.71 +/- 0.36 for pigs. Thus, there was significantly less neointimal thickening in dogs compared with pigs (P < .001) despite no differences in injury (P = NS). The neointimal thickening differences translated into significantly different percent area stenoses: 55 +/- 24% for pigs versus 27 +/- 13% for dogs (P < .001). Linear regression modeled neointimal thickness versus injury assessed by an ordinal injury score proportional to the depth of injury for each species. This analysis confirmed the differences across multiple injury levels. The slope of the regression line for dogs was small, suggesting that no relation may exist between injury and neointimal thickness in this species. The pig may be a more appropriate model for the study of the genesis of stenosing neointima.(ABSTRACT TRUNCATED AT 250 WORDS)

A clinician's overview of laser systems for cardiovascular applications

This paper discusses the current lasers used in cardiovascular applications and presents an overview on function, characteristics, and tissue interactions of the principal lasers used in this field. The discussion includes the lasers and delivery systems currently in use, or with potential future application, for laser angioplasty and laser recanalization. Included are low-intensity laser as well as high-power laser applications.

Balloon dilation catheters

Catheter therapy has gained an important role in the treatment of congenital heart disease. The cumulative experience with vascular and valvular balloon dilations has demonstrated low mortality and morbidity with short-term results similar to surgery. Currently, balloon dilation is an accepted treatment for valvular pulmonary stenosis, distal pulmonary artery stenosis, recurrent coarctation, rheumatic mitral stenosis, congenital valvular aortic stenosis, and intra-atrial baffle obstruction. Except for patients at high surgical risk, balloon dilation of native coarctation is considered investigational at most institutions but accepted at others. No conclusive evaluation is yet possible for dilation of bioprosthetic valves and membranous subaortic stenosis. Individual pulmonary veins appear undilatable. Various devices are available for closure of extra- and intracardiac communications. Transcatheter closure of aortopulmonary collaterals and arteriovenous malformations is now well established at some centers. In selected patients, therapeutic embolization of surgical shunts can replace surgery. Transcatheter closure of the patent ductus arteriosus has become routine at some centers. Nonsurgical closure of atrial and ventricular septal defects has entered clinical trials, and preliminary results appear very promising. Blade atrioseptostomy and foreign body retrieval are well established. Improvement of existing procedures and implementation of new concepts will consolidate the role of catheter therapy in congenital and acquired heart disease.

Laser balloon angioplasty: technical realization and vascular tissue effects of a modified concept

A modified concept using a movable fiber with radial light dispersion was developed for combining mechanical balloon dilatation and intraluminal circumferential Nd-Yag laser irradiation of the arterial wall. The aims of the study were the technical feasibility and the acute and chronic vascular tissue effects of laser-assisted balloon dilatation. The carotid arteries (n = 9 dogs) and femoral arteries (n = 5 dogs) of dogs were mechanically dilated and simultaneously circumferentially irradiated through the balloon by 1,064 nm Nd-Yag laser (20-25 W). Temperature at the adventitial surface was kept constant at 50 degrees C, 60 degrees C, 70 degrees C, or 80 degrees C for either 8 or 15 seconds by a computerized feedback system for temperature control. Angiographic and histological results were available acutely, subacutely (2 days), and at 3 months. Angiographically, stable and smooth enlargement of the lumen was demonstrated acutely. At 3 months, occlusions, probably thrombotic in origin, had occurred in 5 of the carotid arteries and none of the femoral arteries. Histologically, laser-induced coagulation of the arterial wall with loss of cellular elements was demonstrated. Collagen and elastic fibers remained relatively intact. In two carotid arteries intimal proliferation was observed at the treated site. Thus, this technique appears to be technically feasible, yet further study is needed to assess its potential to reduce or repair acute vascular complications (dissections) and to reduce restenoses after percutaneous transluminal coronary angioplasty (PTCA). However, the clinical value of this technique appears to be limited in view of the thromboses and reactive proliferations observed in this preliminary study.

CO2-laser radiation damage of the arterial wall

This study describes the effects of CO2 laser radiation on the histology of the normal rabbit arterial wall, using models that simulate laser angioplasty and anastomosis. Rabbit arteries were exposed to laser treatments similar to those used clinically; 40, 0.5 sec pulses of 40-60 mW, CO2 continuous wavelength laser, or a 1/2-circumferential laser anastomosis with a 60-80 mW continuous pulse. Aneurysms developed in 8 of 22 femoral, 1 of 22 carotid, and no controls at 12 week. There were small breaks in the internal elastic lamina with atrophy, loss of muscularis, "packing" of the elastica, thinning of the muscularis at the damage site, and enlargement of the arterial diameter. Aneurysms developed in one femoral and no carotid anastomosed artery. Laser anastomoses demonstrated more muscle damage and loss, with extensive scarring and a wider area of elastic loss than the controls. The intima was reestablished with focal reduplication of the internal elastic lamina. There were no histologic differences between the arteries which developed aneurysms and those which did not in either series. These results suggest that low power laser damage of the arterial wall consists mainly of destruction of the muscularis propria, with minimal damage to the elastica.

Laser balloon angioplasty versus balloon angioplasty in normal rabbit iliac arteries

Reduction of vascular recoil is an important goal of laser balloon angioplasty (LBA), wherein Nd:YAG laser radiation is delivered radially during balloon inflation. To define the acute and chronic effects of LBA on the normal arterial lumen in comparison with those of balloon angioplasty (BA), 36 New Zealand White male rabbits (3-4 kg) were subjected to LBA of an external iliac artery and to BA of the contralateral artery with two 1-minute balloon inflations. During LBA, which was performed during the second balloon inflation, either 300 (n = 26) or 176 (n = 10) J were delivered to achieve high and moderate laser doses, respectively, in different LBA groups. Angiography was performed pre- and post-LBA/BA and subsequently at intervals of either 1, 2, 7, 28, 48, or 223 days. Automated analysis of digitized images was used to measure lumen diameter. No instance of perforation or thrombosis occurred. LBA-treated arteries acutely showed an increase in mean diameter over baseline (+ .5 mm, P less than .01) and that of BA-treated arteries (+ .4 mm, P less than .01). While arteries treated with the high laser dose showed a loss of the initial gain in lumen diameter by 1 month, caused by both extravascular fibrosis of the thinwalled (less than 0.1 mm) artery and mild neointimal proliferation which were not reduced by daily administration of aspirin in seven rabbits, arteries treated with the moderate laser dose retained the increment in mean diameter at 1 month over that of BA-treated arteries (+ .5 mm, P less than .05). Thus, unlike BA, LBA increases luminal diameter acutely and, at a moderate laser dose, chronically.

Predictors, therapeutic options and long-term outcome of abrupt reclosure

To ascertain the clinical and procedural factors that relate to the occurrence and management of abrupt reclosure, data on 1,160 consecutive patients who underwent coronary angioplasty between December 1981 and December 1986 were analyzed. Abrupt reclosure occurred in 54 patients (4.7%), developing during the dilatation procedure in 43 patients (80%) and delayed by 11 +/- 2 hours after the procedure in 11 patients (20%). Patients were divided into 3 groups based on subsequent management: (1) 22 patients (40%) in whom the involved vessel was reopened by additional dilatation, (2) 14 patients (26%) in whom the involved vessel was not reopened but the patient was treated medically, and (3) 18 patients (33%) in whom abrupt reclosure was managed by emergency bypass surgery, yielding an overall emergency surgery rate of 1.6%. Patients whose abrupt reclosure was reopened were more likely to have luminal thrombus (54 vs 28%) and less likely to have extensive local dissection after dilatation (14 vs 61%; p less than 0.025) than patients undergoing emergency surgery. Patients treated medically despite continued vessel occlusion were more likely to have collateral blood flow to the occluded zone (54 vs 11%, p less than 0.01) than patients undergoing surgery. While 10 of 18 patients (56%) undergoing emergency surgery sustained a myocardial infarction, all patient subgroups appeared to do well during long-term follow-up.