Biomedical subjects

M M Swindle

Publications and source records attributed to M M Swindle.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Percutaneous serial catheterization in swine: a practical approach.

In a model designed for experimental cryoablation of the His bundle in swine, a study that required multiple and follow-up cardiac catheterizations, femoral percutaneous cannulations were successfully performed in 14 of 15 swine: 6/6 Yucatan miniature, 5/6 Hanford miniature, and 3/3 Yorkshire farm pigs, weight range 15-50 kg. A follow-up cardiac catheterization was performed in 10 of these animals: 5 Hanford and 5 Yucatan. Femoral percutaneous cannulation was successful in 6. A cutdown approach was successful in the remaining 4 after failed attempts at percutaneous vascular access. The results show that percutaneous femoral cardiac catheterization is a feasible and practical technique for cardiovascular studies in swine, especially those that require multiple and serial catheterizations.

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PubMedDate not supplied

Considerations of specific pathogen-free swine (SPF) in xenotransplantation.

The purpose of this manuscript was to introduce the complexities involved in defining both the appropriate health status and the management programs for SPF swine as they may relate to xenotransplantation. One factor that must always be considered in using swine is that they are considered agricultural animals regardless of their purpose and are regulated as such by municipalities, states, and countries. There are nonflexible regulations related to the interstate transportation of swine and even greater hurdles to international transportation. For example, I tried unsuccessfully for three years to transport a single breeding animal with a congenital heart defect to collaborators in the United Kingdom. Bureaucratic factors on both sides of the Atlantic proved insurmountable because the regulations were formulated for economic and isolation purposes and no exceptions could be granted for research animals. Another factor to be considered is the designation of SPF swine, which in this species has a specific proprietary connotation. If the finalized program for production of swine for xenotransplantation proves to be different from the already established SPF program, then a different designation may have to be used. For example, a term like "xenografic defined flora (XDF)" swine could be used to avoid confusion with the already established registry. If xenotransplantation using swine becomes a reality, then it is important that the parameters used to select such animals be defined in advance. It is unlikely that conventionally reared animals of uncertain health status will be widely accepted because of legal and ethical considerations. Likewise, I do not believe that the use of swine for xenotransplantation will be able to avoid the regulatory measures already in place for laboratory animals. The multidisciplinary approach to the problem initiated by the Institute of Medicine workshop is the most appropriate mechanism for resolving the issues.

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PubMedDate not supplied

A technique for conducting noninvasive cardiac electrophysiology studies in conscious swine.

A noninvasive method was developed in swine for conducting cardiac electrophysiology (EP) studies without the potential confounding effects of sedatives or anesthetics. Following a 1-week conditioning regimen in the EP laboratory, 1-month-old Hanford miniature swine underwent transvenous pacemaker (PM) implantation under isoflurane anesthesia. Two bipolar screw-in pacing leads were inserted into the left external jugular vein, with one positioned in the right atrial appendage and one in the myocardium at the right ventricular apex. The leads were attached to a multiprogrammable pulse generator, and the pacing system was placed in a subcutaneous pocket. At weekly intervals following implantation, conscious, unsedated swine were remained in a sling for noninvasive programmed stimulation (NIPS) using a programmable telemetry system. A NIPS protocol to induce arrhythmias was performed separately for the atrium and ventricle. Data for this model are reported. Complications occurred in 6 of 26 animals studied and included one infection of the PM pocket, three cases of dislodgement of the atrial lead, and rotation of the generator within the pocket in two animals, preventing communication with the PM. This technique has been used to perform EP studies successfully in swine and has been utilized in a variety of studies of the cardiac conduction system.

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PubMedDate not supplied

An adult canine model of progressive left ventricular pressure overload.

This article details the development of a model of progressive left ventricular pressure overload (LVPO) in the adult dog. LVPO was induced by banding the proximal ascending aorta in 69 adult conditioned dogs. The base of the aorta was exposed through a right thoracotomy. A tunnel was created by blunt dissection between the aorta and pulmonary arteries. An aortic band was constructed by passing umbilical tapes through the lumen of gortex tubing. This band was placed through the tunnel, then tied around a balloon dilatation catheter. The distal end of the balloon catheter was closed with an injection cap and positioned in a subcutaneous pocket. Aortic stenosis was induced by filling the balloon catheter with saline. A predetermined amount of LVPO was created by adjusting the amount of aortic stenosis. At 2, 4, and 6 weeks after aortic banding the LVPO was increased by transcutaneous injection of saline into the balloon catheter. At 8 weeks the dogs were evaluated for sufficiently decreased cardiac contractility and used acutely in one of several studies. The article also discusses perioperative management, postoperative care, and complications that were encountered during the development of the model. Postoperative pain was managed by the combined use of preemptive and postoperative opioids, local nerve blocks, and nonsteroidal anti-inflammatory drugs. Notable intraoperative complications included atrial and ventricular arrhythmias and pulmonary artery laceration during the banding procedure. The most significant postoperative complications were aortic ruptures and congestive heart failure. The success rate of this model has increased from 20% (year 1) to 65% (year 3). This success has been attributed to improvements in band design, surgical technique, and postoperative management.

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PubMedDate not supplied

Chronic cannulation and fistulization procedures in swine: a review and recommendations.

Swine are important animal models in biomedical research. Some experimental procedures may require chronic access to blood vessels, organs, and structures. Chronic access procedures may be utilized for collection of blood and body fluids as well as for the infusion of test substances. This manuscript reviews methodologies that have been reported to be effective for these procedures. It also makes recommendations on the maintenance of indwelling catheters, cannulas, and fistulas.

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