Biomedical subjects

A Cuschieri

Publications and source records attributed to A Cuschieri.

419 records · Page 24Linked to original sources

PubMedDate not supplied

Shape memory alloy fixator system for suturing tissue in minimal access surgery.

A new technique for suturing human tissue is described in which tissue closure is achieved by means of small fixators made from shape memory alloy. The aim of the development is to provide an alternative to thread suturing in minimal access surgery, which is quicker and requires less skill to achieve the required suturing quality. The design of the fixators is described in terms of the thermal shape recovery of shape memory alloy and a novel form of finite element analysis, which uses a nonlinear elastic element for the material property. Thermal analysis of the fixators and surrounding tissue is used to predict the temperature distribution during and after the application of electric current heating. This was checked in an in vitro experiment, which confirmed that deployment caused no detectable collateral damage to surrounding tissue. In vivo animal studies on the use of the shape memory alloy fixator for suturing tissue are ongoing to establish safety and healing effects.

Alloys↗

PubMedDate not supplied

Inhibition of proteinase-like peptidase activities in serum and tissue from breast cancer patients.

The inhibitory profiles of several proteinase-like peptidases active on synthetic peptide (MCA) substrates, present in sera and 100,000g supernatants of malignant tissue from patients with breast cancer, have been studied using a series of known inhibitors including epoxysuccinyl peptides (E-64, Ep-475), Z-Phe-Phe-diazomethane, PMSF, iodoacetamide, 1-10-O-phenanthroline, leupeptin, aprotinin, elastatinal and alpha 2-macroglobulin. While in general the inhibition profiles confirmed reported substrate specificities some anomalies were observed. In particular, the serum activities on two cathepsin B substrates were unaffected by specific cysteine proteinase inhibitors and in breast tissue only 20-37% of activity towards these two substrates was apparently due to the presence of endopeptidases. However, the potent inhibition of other proteinase-like activities by the epoxysuccinyl peptides and leupeptin, or similar inhibitors, may be useful agents in the study of methods of combating tumour spread.

Breast Neoplasms↗

PubMedDate not supplied

Experimental evaluation of water-jet dissection in endoscopic surgery.

The problems associated with high-velocity high-pressure water-jet dissection were investigated by in-vivo experiments using endoscopic equipment. Three problems were identified: backspray with fouling of the optic, poor control of the depth of cut, and detachment of tissue fragments and isolated cells which contaminate the operative field. The first two problems have been resolved by adoption of a hooded hand-piece and the incorporation of an adjustable back stop. A "dry" system which enables the evacuation of the back spray may deal with the problem of contamination of the operative field by detached cells but further in-vivo experiments are needed to confirm this. Until then, water-jet cutting is considered unsafe for both open and endoscopic surgery in patients undergoing extirpative procedures for cancer because of the risk of tumour seeding within the peritoneal cavity.

Dissection↗

PubMedDate not supplied

Endoscopic oesophageal myotomy for specific motility disorders and non-cardiac chest pain.

The management of oesophageal motility disorders has been unsatisfactory due to the lack of effective pharmacological treatment. Endoscopic surgical myotomy offers an effective long-term therapy without the disadvantages of a thoracotomy. After characterization by oesophageal manometry 12 patients with achalasia and 23 patients with non-cardiac chest pain were considered suitable for myotomy. For achalasia, the laparoscopic approach was preferred to the thoracoscopic route. Fundoplication was not performed unless a hiatus hernia was present or as a buttress protection following suture of an iatrogenic perforation of the oesophageal mucosa. For patients with non-cardiac chest pain a thoracoscopic long myotomy was performed from the left side with the patient operated on in the postero-lateral position. Three perforations (all sutured endoscopically) were encountered: two during cardiomyotomy, one during long myotomy. Complete or substantial relief of chest pain was encountered in 18 patients, with five patients having no relief of their pain. Our experience indicates that long myotomy is successful but longer term follow-up is required to assess its therapeutic role.

Adult↗

PubMedDate not supplied

Coaxial curved instrumentation for minimal access surgery.

New coaxial curved and bayonet instruments have been designed which permit controlled dissection and directional change of the functional tip, blunt dissection and lift retraction. The instruments are introduced into the peritoneal and thoracic cavities through flexible re-usable metal cannulae. The excellent ergonomic properties of the new instruments have been confirmed by their use in major laparoscopic and thoracoscopic operations. Coaxial instruments enhance the scope of minimal access surgery and have distinct advantages over the traditional straight instruments.

Biomechanical Phenomena↗