Self-expanding nitinol stents in canine vertebral arteries: hemodynamics and tissue response.

PURPOSETo evaluate the hemodynamics and tissue response associated with stent placement in low-flow-velocity arteries.METHODSSix self-expanding nitinol stents (5.5 mm caliber) were implanted transfemorally within the proximal segments of vertebral arteries (2.5 mm diameter) in six adult dogs during anticoagulative protection.RESULTSControl angiograms demonstrated patency and 20% dilatation of all stented arteries. One artery was partially thrombosed 1 week later and subsequently showed a 50% stenosis. Throughout the observation period (4 to 9 months after stenting), the other five arteries remained patent without significant narrowing (< or = 15%). Small cervical muscle branches originating from the vertebral arteries within the stented segments remained patent. No major branch occlusions of the vertebrobasilar system were detected. Stent migration or kinking did not occur. MR studies of the brain 4 months after implantation revealed no infarcted areas. These findings were confirmed with brain sections. Stented artery specimens showed delayed stent dilatation. A comparison of the total mean thickness of intima covering the five 30- to 40-mm stents removed at 4, 6, and 9 months showed no significant difference (338, 332, and 389 microns, respectively). Histologic findings verified the macroscopic impression of a thicker intima at the inner curve of the stented artery segments and at the junctions of the stent filaments. The shortest (10 mm) stent had the thinnest neointimal growth (155 microns). Stented vessels showed compression of the media with atrophy, but without necrosis or perforation. Scanning electron photomicrographs revealed intact endothelial cell linings with typical elongated cells.CONCLUSIONSNo significant risk of thromboembolic events exists after implanting these nitinol stents in nonatherosclerotic vertebral arteries in dogs. Thicker neointimal growth after stenting may result from either low wall shear stress with possible flow separation or from changes in the shape and size of the stent, or both.     

A tumor-targeted and conditionally replicating oncolytic adenovirus vector expressing TRAIL for treatment of liver metastases.

We have constructed a new capsid-modified adenovirus (Ad) vector that specifically replicates in tumor cells and expresses TNF-related apoptosis-inducing ligand (TRAIL). The Ad capsid contains short-shafted fibers derived from Ad serotype 35, which allow for efficient infection of malignant tumor cells, and largely avoids innate toxicity after intravenous application. Replication-dependent homologous recombination in Ad genomes was used to achieve tumor-specific expression of Ad E1a (to mediate viral replication) and TRAIL (to mediate apoptosis and enhance release of progeny virus from infected cells). We demonstrated that our oncolytic vector (Ad5/35.IR-E1A/TRAIL) induced apoptosis in human tumor cell lines derived from colorectal, lung, prostate, and liver cancer. Both in vitro and in vivo tumor models showed efficient intratumoral spread of this vector. In a model for metastatic colon cancer, tail vein infusion of Ad5/35.IR-E1A/TRAIL resulted in elimination of preestablished liver metastases. Intravenous injection of this vector caused a transient elevation of serum glutamic pyruvic transaminase in tumor-bearing mice, which we attributed to factors released from apoptotic tumor cells. Liver histology analyzed at day 14 after virus injection did not show signs of hepatocellular damage. This new oncolytic vector represents a potentially efficient means for gene therapy of metastatic cancer.     

Perfluorochemicals as US contrast agents for tumor imaging and hepatosplenography: preliminary clinical results

In animals, perfluorochemicals (PFCs) are effective ultrasound (US) contrast agents that produce hepatic, splenic, and tumor enhancement. The use of Fluosol-DA 20%, an emulsion of perfluorodecalin and perfluorotripropylamine, was studied in nine non-critically ill patients with cancer who had liver lesions. US studies without Fluosol were compared with studies obtained 24, 48, and 72 hours after Fluosol infusion. Vital signs and extensive laboratory analyses are performed before and after Fluosol infusion. Liver metastases from colonic, pancreatic, and gastric carcinoma exhibited rim or diffuse enhancement after a Fluosol dose of 1.6 g/kg or greater. Fluosol produced echogenic enhancement of the liver and spleen relative to kidney at a dose of 2.4 g/kg, allowing the detection of nonenhancing lesions. In addition, Fluosol at a dose of 1.6 g/kg or greater allowed detection of lesions not seen before contrast medium was administered in three of the seven patients studied. There was a mild increase in the level of serum glutamic oxaloacetic transaminase in two patients, one given 2.4 and the other 3.2 g/kg of Fluosol. Mild and transient allergic reactions without change in vital signs were experienced by two patients.     

Classical and anaplastic seminoma: difference in survival

Classical and anaplastic seminoma are traditionally treated with radiation therapy and are said to have the same prognosis. A retrospective study was undertaken of 90 seminoma patients treated with radiation therapy between 1961 and 1985. The classical group consisted of 71 patients of whom 50 had stage I and 21 had stage II disease. The anaplastic group consisted of 19 patients of whom ten had stage I and nine had stage II disease. The median follow-up time was 64 months for the entire group. The 10-year relapse-free survival rate for the classical group was 94% and for the anaplastic group was 70% (P less than .05). For patients with classical stage I disease, the relapse-free actuarial survival rate was 98%; for patients with anaplastic stage I disease, it was 64% (P less than .02). For the classical stage II disease group, the relapse-free actuarial survival rate was 84% and for the anaplastic stage II disease group, 75% (P less than .70). Four patients in the classical group (6%) had relapses; of these, one patient had local recurrence of tumor, and three had distant metastases. In the anaplastic group, four patients (21%) had relapses; two patients had local recurrence of tumor, and two had distant metastases. Therefore the data suggest a difference in survival and relapse rates between classical and anaplastic seminoma.     

骨骼肌的生物力学

骨骼肌能产生力和运动,肌肉的收缩与运动的激发完美协调。本文回顾骨骼肌的生物力学特点,描述力的产生和力通过肌细胞的传递。首先描述正常的肌肉结构特征和不同的肌肉结构形式,随后讨论肌肉的功能及其结构对功能的影响,分析收缩蛋白与中间肌丝在力从细胞内肌小节传递到细胞外基质过程中的相互作用。