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Biomedical subjects

B E Jarrell

Publications and source records attributed to B E Jarrell.

At least 37 records · Page 2Linked to original sources
PubMed1992

Formation of a multilayer cellular lining on a polyurethane vascular graft following endothelial cell sodding.

Small-diameter (less than 6 mm) clinically available vascular grafts often fail due in part to the inherent thrombogenicity of artificial polymers. Transplantation of endothelial cells onto the lumen of these vascular grafts has been suggested as one method to overcome this thrombogenicity. We have developed a compliant polyurethaneurea (PEUU) 4-mm graft with a luminal surface modified by a glow discharge gas plasma. Autologous microvessel endothelial cells were isolated from canine falciform ligament fat, were transplanted onto the luminal surface of the grafts using an intraoperative isolation and sodding technique, and both endothelial-cell-treated and non-cell-treated grafts were placed as bilateral carotid interposition grafts in a canine model. After 5 weeks of implantation, explanted control (non-cell-treated) grafts exhibited a deposition of platelets, white cells and fibrin characteristic of a thrombogenic surface. MVEC sodded grafts exhibited a multicellular lining within but distinct from the lumen of the PEUU graft. The blood-contacting surface of this lining exhibited an antithrombogenic endothelial cell monolayer. We suggest that the PEUU graft supported the initial deposition of MVEC and development of and endothelial cell lining. During the 5 weeks of implantation this lining continued to proliferate and detached from the PEUU graft substratum. The final neocellular lining exhibited a luminal diameter and histological features similar to a native artery.

Animals↗
PubMed1992

A porcine model for adipose tissue-derived endothelial cell transplantation.

The transplantation of endothelial cells represents a technology which has been suggested for applications ranging from improvement in function of implanted vascular devices to genetic therapy. The use of microvascular endothelial cell transplantation has seen increased use both in animal studies as well as clinical use. This report describes our techniques for the isolation and establishment of initial cultures of microvascular endothelial cells derived from porcine fat. A variety of anatomic sites within the pig were evaluated to determine the appropriateness of different sources of fat for endothelial cell isolation. The properitoneal fat was determined to be optimal due to the predominance of endothelium in this tissue and the ease of isolation of microvascular endothelium following collagenase digestion. The study of endothelial cell transplantation in the porcine model is now possible using the methods described for adipose tissue-derived microvessel endothelial cell isolation.

Actins↗
PubMed1991

Formation of a functional endothelium on vascular grafts.

The lack of a functional endothelial cell lining on artificial polymeric vascular grafts severely reduces their effectiveness in replacing small caliber (less than 6 mm) blood vessels. Techniques have now been developed to transplant autologous endothelial cells from one site in the body onto the surface of grafts prior to implantation. Pre-clinical animal trials provide evidence that grafts sodded with autologous, fat-derived, microvessel endothelial cells exhibit a stable, antithrombogenic lining of endothelium. The new endothelial cell lining exhibits morphologies identical with endothelium on native blood vessels. The effectiveness of endothelial cell sodding techniques in pre-clinical animal trials provides support for expanded clinical trials.

Animals↗
PubMed1991

Cultured and immediately procured endothelial cells: current and future clinical applications.

Great progress has been made in the last several years in our ability to culture human endothelial cells. In addition, techniques to immediately procure and utilize these cells have also been developed. The purpose of this paper is to present an overview of the current and potential uses of these cells in both vascular and nonvascular conditions. It is likely that endothelial cells will be used in a variety of applications in the near future. Immediately procured and cultured cells will be used to resurface vascular prosthetic grafts. They may also be used on the surface of vessels following procedures such as balloon angioplasty or atherectomy. In addition, they may be placed upon the surface of implantable devices such as expandable stents. Through the mechanism of genetic engineering, these cells may be modified to produce proteins, which may modify thrombogenicity and perhaps decrease the rate of recurrent stenosis by influencing cellular hyperplasia. Genetically modified endothelial cells also have great potential in nonvascular disease. Their contact with circulating blood makes them an ideal cell for production of proteins to correct systemic conditions such as the insulin deficiency found in diabetes mellitus. The application of endothelial cell biology in both vascular and nonvascular science represents one of the most exciting fields of research active today.

Blood Vessel Prosthesis↗
PubMed1991

Microvessel derived endothelial cell isolation, adherence, and monolayer formation for vascular grafts.

MVECs can be isolated from animal and human fat in quantities and in a pure enough form to produce a cell-lined vascular graft. In animal studies grafts treated with these cells are associated with prolongation of graft patency. In human implants definitive expression factor VIII related antigen cells has been performed on an MVEC treated graft at 9 months. Further studies will be necessary to provide further insight into the healing and long-term behavior of these grafts, both with respect to the thrombogenicity of the surface as well as the influence on anastomotic hyperplasia.

Animals↗
PubMed1991

Estimation and characterization of the potential renal organ donor pool in Pennsylvania. Report of the Pennsylvania Statewide Donor Study.

The Pennsylvania Statewide Donor Study evaluated deaths under the age of 66 occurring in 149 participating hospitals in 1987. After elimination of 6146 patients from 11,983 based upon ICD-9 code criteria, an on-site medical record review was performed on 5603 patients. Each patient was assessed for organ donor suitability based upon brain death and medical suitability criteria--and, after a series of eliminations, 453 patients were found to have a moderate or higher potential as acceptable organ donors. An estimation of the organ donor rate was placed between 38.3 and 55.2 donors per million population per year, depending upon the stringency of organ donor criteria. Educational efforts targeted at physicians, patient's families and transplant surgeons will be necessary, however, to attain this maximal rate.

Adult↗
PubMed1991

Optimization of human endothelial cell attachment to vascular graft polymers.

Endothelial cells (EC) covering the blood-contacting surface of a prosthetic material could potentially enhance the subsequent nonthrombogenicity of the surface. In order to create such a surface, the EC must become attached to the surface, spread and ultimately form a monolayer. In this study we examined several factors that influence these processes. On ePTFE surfaces, surface pretreatment with human serum for 30 minutes at a concentration of 1.4 gm percent protein resulted in significantly more attached EC when compared to other concentrations or when compared to fetal calf serum or human serum albumin. The rate of EC spreading was strongly influenced by temperature, with a maximum occurring at 37 degrees C. During real-time video microscopy, it was noted that the rate of EC attachment and spreading was primarily dependent on arrival of the EC to the surface rather than attachment and spreading. Thus as a method of increasing EC delivery, the concept of filtering EC onto the graft lumenal surface was tested by pressurizing the graft lumen to speed EC delivery to the surface. This technique produced a 2 to 5-fold increase in EC attachment when compared to gravity forced cell deposition. We conclude that an ePTFE graft can be rapidly endothelialized using these simple measures.

Biocompatible Materials↗
PubMed1991

Recurrence of hepatitis C virus infection after orthotopic liver transplantation.

Identification of the hepatitis C virus--the main cause of posttransfusion and sporadic non-A, non-B hepatitis--and the development of a diagnostic serological test have allowed us to study possible recurrence of this type of hepatitis after liver transplantation. Six of 34 consecutive transplant recipients were found to have had antibodies to hepatitis C before transplantation. All six patients had possible exposure to hepatitis C through blood transfusion or intravenous drug use. Five of the six patients were positive for antibodies to hepatitis C after 1 yr of follow-up. Two of these patients had clinical and histological evidence of acute viral hepatitis in their allografts. In one patient this led to hepatic injury and dysfunction of two successive grafts. In contrast, none of the twenty-eight patients who were seronegative for hepatitis C virus antibodies before transplantation has converted to seropositivity after transplantation despite perioperative blood transfusions. These results suggest that hepatitis C diagnosed serologically recurs in a minority of transplant recipients and that de novo seroconversion must be uncommon.

Adult↗
PubMed1990

Heterotopic liver transplantation for fulminant Wilson's disease.

Wilson's disease may present with severe acute hepatocellular failure. The only effective treatment for fulminant Wilson's disease is liver transplantation, which may lead to reversal of the underlying disease. Some patients with cirrhosis who are too ill to undergo orthotopic liver transplantation have been treated with heterotopic liver transplantation. However, use of heterotopic liver transplantation for fulminant hepatocellular failure has not been successful. This case study involves a patient in whom a heterotopic liver transplant was successfully used for treatment of Wilson's disease presenting with fulminant hepatocellular failure.

Adolescent↗
PubMed1990

Thrombus-free, human endothelial surface in the midregion of a Dacron vascular graft in the splanchnic venous circuit--observations after nine months of implantation.

The addition of an endothelial cell lining to a prosthetic vascular graft may reduce the thrombogenicity of the blood-contacting surface. An endothelialized mesoatrial graft was implanted in a patient with Budd-Chiari syndrome caused by a primary inferior vena caval leiomyosarcoma. During the initial surgery a Dacron vascular graft was preclotted with plasma and then lined with microvascular endothelial cells derived from the patient's subcutaneous adipose tissue. The patient did well initially but 9 months later required resection of a mechanical stricture of the graft that occurred as it passed beneath the costochondral junction. Grossly, the luminal surface of the resected graft was free of thrombus, with a smooth, glistening, white surface. Light microscopy demonstrated a surface layer of cells morphologically consistent with an endothelial cell monolayer, a subendothelial layer composed of extracellular matrix and spindle-shaped cells, and granulation tissue around the Dacron fabric. Immunohistochemistry and electron microscopy confirmed the presence of vascular endothelium on the luminal surface. This report documents the successful achievement of a human endothelial cell monolayer that persisted for 9 months in the midportion of a Dacron vascular graft.

Adult↗
PubMed1990

Electron microscopy of endothelial cell-biopolymer interaction.

Vascular endothelial cells form a natural antithrombogenic lining on all blood vessels. Replacement or bypass of small diameter blood vessels with artificial polymeric grafts has not been clinically acceptable due to the thrombogenic nature of polymeric material. One approach to improving the patency of vascular prosthetic devices has been the establishment of endothelial monolayers on the blood flow surface using the technique known as seeding. Scanning electron microscopy has been a major tool in evaluating the interaction of endothelial cells with polymeric surfaces resulting in a basic understanding of forces and structures regulating endothelium-polymer interactions. In-vitro and in-vivo studies have established the feasibility of using endothelial cell seeding technology in human clinical trials. This tutorial describes the development of endothelial cell seeding technology and illustrates how scanning electron microscopic evaluations have furthered our understanding of endothelial cell-polymer interactions.

Biopolymers↗