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Biomedical subjects

Paul Breedveld

Publications and source records attributed to Paul Breedveld.

6 recordsLinked to original sources
PubMed2006

Stick, unstick, restick sticky films in the colon.

The main challenge in designing diagnostic devices able to move along the colon is their locomotion method. Manipulating friction with the colonic surface is a key requirement for their safe and atraumatic propagation. One possible solution is to generate friction by means of adhesive forces. For this reason, a diagnostic device can be covered with mucoadhesive films that are able to stick on the colonic surface by generating high static friction. For a smooth transition from static to dynamic regime, the mucoadhesive films should unstick just before the initialisation of motion. Experiments have shown that promoting cohesive fracture of the films by controllable air introduction does not lead to friction reduction sufficient for smooth unsticking. Introducing water at the film-colon interface, however, reduces the static friction significantly, and makes the device to unstick and slide smoothly without leaving film fragments on the colonic surface behind. If unsticking is initiated by means of air or water introduction, a new film is required each time the device is required to restick. As an alternative, the possibility of coating the device with environmentally-sensitive mucoadhesive polymers that can respond reversibly to external stimuli and alter their properties is discussed.

Adhesiveness↗
PubMed2005

Mucoadhesives in the gastrointestinal tract: revisiting the literature for novel applications.

This article investigates applying mucoadhesives to manipulate friction and to achieve locomotion of an alternative colonoscopic device through the large intestine. Considering that such an application of mucoadhesives is new, the authors recognised the need to revisit the different aspects of mucoadhesion in the gastrointestinal tract on the basis of the literature and to re-evaluate them according to the requirements for intestinal locomotion. First, the material properties, which are critical for the locomotion mechanism and specific categories of mucoadhesives characterised by those critical properties were identified. The next step was to examine the structural characteristics of those categories to specify which of the already synthesised mucoadhesives are promising candidates for friction manipulation. Then, the response of those mucoadhesives to a number of environmental stimuli was examined. At the end, two in vitro experiments were carried out to study the potential of mucoadhesives for intestinal locomotion. A comparative analysis of the role of mucoadhesives in drug delivery and in intestinal locomotion leads to the conclusion that the two applications can be approached to one extent with common principles, but crucial differences are present as well.

Adhesives↗
PubMed2005

Friction manipulation for intestinal locomotion.

The importance of colonoscopies on the one hand and the drawbacks of the conventional instrumentation on the other have led to research into alternative colonoscopic devices. The main question for the development of such devices is the method of locomotion along the slippery and flaccid intestinal tube. This paper suggests a new intestinal locomotion method based on friction manipulation between the device and the intestinal wall. A new concept to manipulate friction is described. The concept is based on the active alterations of the friction between the device and the intestinal wall and it is inspired by the locomotion of biological species such as snails and starfish.

Journal Article↗
PubMed2004

Camera and instrument holders and their clinical value in minimally invasive surgery.

During minimally invasive procedures an assistant is controlling the laparoscope. Ideally, the surgeon should be able to manipulate all instruments including the camera him/herself, to avoid communication problems and disturbing camera movements. Camera holders return camera-control to the surgeon and stabilize the laparoscopic image. An additional holder can be used to stabilize an extra laparoscopic instrument for retracting. A literature survey has been carried out giving an overview of the existing "robotic" and passive camera and instrument holders and, if available, results of their clinical value. Benefits and limitations were identified. Most studies showed that camera holders, passive and active, provide the surgeon with a more stable image and enables them to control their own view direction. Only the passive holders were suitable for holding instruments. Comparisons between different systems are reviewed. Both active and passive camera and instrument holders are functional, and may be helpful to perform solo-surgery. The benefits of active holders are questionable in relation to the performance of the much simpler passive designs.

Equipment Design↗
PubMed2003

Pro/con clinical debate: antibiotics are important in the management of patients with pancreatitis with evidence of pancreatic necrosis.

Pancreatitis is not an infrequent diagnosis in patients admitted to the intensive care unit. Prolonged stays, intense resource utilization and high morbidity/mortality are commonplace in such patients. Management for the most part is supportive, with the surgical team keeping close watch to intervene as the need arises. Over the past few decades there has been considerable debate regarding the usefulness of systemic antibiotics to prevent infectious complications in patients with evidence of pancreatic necrosis. In the present article of Critical Care, two expert groups debate the two sides of this contentious antibiotic issue.

Adult↗