Most patients failed to understand the risks and benefits associated with CEA. Some patients' estimates of stroke risk were actually greater than the perceived potential benefit of surgery in terms of risk reduction. The data also suggested a positive correlation between the degree of perceived benefit and the degree of perceived risk.
This study investigated the effect of different surface coatings on endothelial cell attachment to polytetrafluoroethylene (PTFE) vascular grafts. Small segments of PTFE vascular grafts were precoated with one of a number of substances: gelatin, poly-l-lysin, fibronectin, or collagen type I, III or IV. Indium-111 labelled endothelial cells were then seeded on to the grafts and left for either 10, 30, 60 or 120 min. The unattached cells were removed and the degree of cell attachment was calculated. All coatings were significantly better at enhancing endothelial cell attachment at all times compared with controls, and fibronectin was significantly better as a coating material than any other material used. By pretreating with a substance such as fibronectin, the number of endothelial cells attaching to PTFE vascular grafts can be greatly increased, thereby enhancing the cell seeding process.
Matrix metalloproteinases (MMPs) play an important part in the expansion of abdominal aortic aneurysms (AAA). It has been suggested that MMPs appear to be present in differing concentrations during the progression of aneurysm development. Our aim was to determine the MMP profiles in tissue from aneurysms of differing sizes, to define whether rupture results from gradual widespread increases in proteolytic capacity, or is confined to a localized area of the aortic wall. Samples of anterior aortic wall were obtained from 81 patients undergoing elective AAA repair (n = 59, median age 72 years, diameter 6 cm), or emergency repair of ruptured AAA (rAAA) (n = 22, age 72). The elective group was divided by aneurysm size into 2 groups; medium sized (5–6.5 cm, n = 31, age 70) and large (>6.5 cm, n = 11, age 73). Paired samples of aortic sac were obtained from the sac and the site of aortic rupture from nine patients with rAAA (age 70). MMPs‐1, ‐2, ‐3, ‐9, and ‐13, and TIMPs‐1 and ‐2 were extracted from the tissue specimens and quantified using ELISA. There were no significant differences in MMP and TIMP levels in AAA sac of medium and large sized aneurysms, or ruptured and nonruptured AAA sac. In paired specimens taken from rAAA, MMP‐9 was seven times higher at the site of rupture than in the anterior sac (98.57 ng mg−1[IQR 56.02–134.5]versus 13.89 ng mg−1[7.80–46.81], P = 0.012). These data demonstrate that MMP profiles vary little with expansion of the aneurysm in medium‐ and large‐sized aneurysms. Rupture is likely to be a result of localized elevations in MMP‐9 and this would be an appropriate target for pharmacotherapy.
Correspondence that it is therefore eminently possible to tailor screening protocols to suit individual needs.Third, it is stated that individuals with a family history of colorectal cancer have a propensity to develop right-sided lesions. Although this is the case for hereditary non-polyposis colorectal cancer, there is no evidence that it is so for those with a familial tendency.Finally, he points out that it is inappropriate to carry out an incomplete examination on screened patients and thereby perhaps give false reassurance. We would agree with this general sentiment but must point out that he has partly based his viewpoint on a study that found no more pathology in these people than in the general population3. Colonoscopy is an investigation with a morbidity and mortality rate. We believe that the evidence to advocate a 'blanket' policy of colonoscopy for all levels of family risk has not been shown by the currently available data. McConnell JC, Nizen JS, Slade MS. Colonoscopy in patients with a family history of colon cancer. Dis Colon Rectum 1990; 33: McConnell JC. Colonoscopy or flexible proctosigmoidoscopy. Dis Colon Rectum 1990; 33: 722. Grossman S, Milos ML. Colonoscopic screening of persons with suspected risk factors for colorectal cancer. I: Family history. Gastroenterology 1988; 94: 395-400. Herrera L, Hanna S, Petrelli N, Nava H. Screening endoscopy in patients with a family history positive ( F H + ) for colorectal neoplasia (CRN). Gastrointesf Endosc 1990; 36: 211 (Abstract). 105-7. 2.3.
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