Dual cell seeding and the use of zymogen tissue plasminogen activator to improve cell retention on polytetrafluoroethylene grafts.

OBJECTIVE: The purpose of this study was to enhance the retention of seeded endothelial cells (EC) on prosthetic vascular grafts. Dual-layer EC and smooth muscle cell (SMC) seeding and gene transfer of a zymogen tissue plasminogen activator gene (tPA) into seeded EC were studied. METHODS: Polytetrafluoroethylene (PTFE) grafts were precoated with fibronectin, seeded with SMC followed by EC a day later, and then, 24 hours later, exposed to an in vitro flow system for 1 hour. Cell retention rates were determined for grafts seeded with EC only, a dual layer of EC on top of SMC, EC transduced with wild-type tPA, and EC transduced with zymogen tPA. RESULTS: Seeding efficiency of PTFE pretreated with fibronectin was 260 +/- 8 cell/mm(2). After exposure to flow, only 39% +/- 14% of the EC were retained when EC were seeded alone, whereas 73% +/- 22% of EC remained on grafts when EC were seeded on top of SMC (P <.001, n = 10). The enzyme activity of a mutant zymogen tPA in absence of fibrin was 14 +/- 1 IU/mL, which is 3.6-fold lower than that in the presence of fibrin (50 +/- 19 IU/mL), whereas fibrin has no effect on the wild-type tPA activity. EC expressing a high level of wild-type tPA had a lower retention rate (37%) when compared with normal EC (45%). EC expressing the mutant zymogen tPA had an improved retention rate (54%, P =.001, n = 10) in absence of fibrin, whereas its retention rate was reduced to 43% when the cells were exposed to fibrin. CONCLUSION: SMC seeded between EC and PTFE improves EC retention in vitro. Transduction of zymogen tPA increases thrombolytic ability of seeded cells with less adverse impact on cell retention than wild-type tPA.

Vascular smooth muscle cell apoptosis in aneurysmal, occlusive, and normal human aortas.

PURPOSE: Apoptosis is a physiologic mechanism of cell death that regulates mass and architecture in many tissues. Apoptosis has been described as a feature in human vascular atherosclerosis and large vessel structural integrity. We examined the extent of vascular smooth muscle cell (VSMC) apoptosis in aneurysmal, occlusive, and normal human aortic tissue. METHODS: Tissue samples of aneurysmal, occlusive, and normal human infrarenal aorta were evaluated. DNA fragmentation detection methods, immunohistochemistry, and DNA electrophoresis determined VSMC density, VSMC apoptosis, and apoptosis markers. Apoptotic cells and VSMC nuclei were counted with the use of computer-generated image analysis. Aortic subtypes were compared statistically by analysis of variance. RESULTS: Seventeen aneurysmal, ten occlusive, and five normal human aortas were evaluated. By alpha(1)-actin immunostaining, VSMC density was least in aneurysmal aortas (271.8 +/- 13.5 cells/high-power field [HPF]) compared with occlusive aorta (278.2 +/- 39.4 cells/HPF) and normal aortas (291.0 +/- 25.4 cells/HPF; P = not significant). Presence of apoptotic VSMCs was demonstrated by terminal deoxynucleotidyl transferase fragment end labeling and propidium iodide nuclear staining. VSMC apoptosis was greatest within aneurysmal aortas with 11.7 +/- 1.5 cells/HPF compared with occlusive aortas with 3.3 +/- 0. 8 cells/HPF (P <.05) and normal aortas with 3.75 +/- 4.6 cells/HPF (P <.05). Significant differences in apoptosis markers, p53 or bcl-2, could not be demonstrated by immunohistochemistry or DNA electrophoresis in aortic subtypes. CONCLUSION: Apoptosis of VSMCs is increased and VSMC density is decreased within the medial layer of aneurysmal aortic tissue. Structural degeneration of aortic tissue at the cellular level contributes to aneurysmal formation.

Combined carotid endarterectomy and coronary artery bypass grafting in asymptomatic carotid artery stenosis.

The role of combined carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) in patients with severe asymptomatic carotid artery disease and concurrent symptomatic coronary artery disease is controversial. The objective of this report is to investigate the safety of combined CEA/CABG. The medical records of 30 patients who underwent combined CEA/CABG for coexistent asymptomatic carotid and symptomatic coronary artery occlusive disease were reviewed. All patients were scheduled for either elective or urgent myocardial revascularization due to their symptomatic coronary artery disease. Color-flow duplex scanning identified internal carotid artery stenosis of 80 to 99 per cent in 28 patients (93%) and 50 to 79 per cent in 2 patients (7%). Seventeen patients (57%) were male. The mean age was 64 +/- 10 years (range, 42-84 years). Contralateral internal carotid artery occlusion was present in four patients. Severe left main coronary artery disease was present in 12 patients (40%) and 7 patients (23%) had an ejection fraction of less than 50 per cent. There were no perioperative deaths or strokes. One patient suffered a myocardial infarction on postoperative day 1. This study demonstrates the safety of combined CEA/CABG for coexistent coronary and asymptomatic carotid disease. Using this surgical approach for critical coexistent disease may minimize the incidence of perioperative cerebrovascular complications in patients undergoing CABG.

Extended resection for locally advanced colorectal carcinoma.

BACKGROUND: The purpose of this study was to determine the therapeutic benefit of multivisceral resection (MVR) in patients with locally advanced colorectal carcinomas. METHODS: The study population was composed of 118 patients whose resection of the primary lesion included one or more adhesed adjacent secondary organs or structures (ASOS). Tumors were staged as B3 (T4,N0) and as C3 (T4,N1-3). Adhesions were classified as invasive (B3+,C3+) or inflammatory (B3-, C3-). RESULTS: Sixty-four patients were staged B3 and 54 C3. Eighty-one were classified B3+/C3+. Fifty-nine percent of patients had ASOS resected, 29% had two resected, and the remaining 12% had three or four resected. Actuarial 5-year survival rates were 62% and 38% (p = 0.017) for B3 and C3 lesions, respectively. The 5-year survival rates were 78% for patients with B3- tumors and 58% for those with B3+ tumors (p = 0.043), and 34% for patients with C3+ tumors and 64% for those with C3- tumors (p = NS). The 5-year survival rates were 71% for patients with B3-/C3- tumors and 47% for those with B3+/C3+ tumors (p = NS). The 5-year survival rates after resection of one ASOS, two ASOS, and three or four ASOS were 52%, 55%, and 38%, respectively (P = NS). CONCLUSIONS: There is no statistically significant difference in the 5-year survival rates when multiple ASOS are resected; therefore, an aggressive surgical approach is warranted.

Operative treatment of gastroesophageal reflux in low birth weight infants.

Operative correction of symptomatic gastroesophageal reflux (GER) has been used frequently and successfully in both children and larger infants for many years. In contrast, surgical repair of GER has been applied relatively sparingly in very small infants because of perceived technical and postoperative difficulties. We retrospectively reviewed our experience with Nissen fundoplications performed for symptomatic GER in low birth weight (LBW) infants ( < or = 2500 grams the time of surgery). Twenty-one consecutive cases from 1988 to 1993 were evaluated. At the time of surgery, the average age was 9.1 weeks and the average weight was 2100 grams (range, 1220 to 2500 grams). All infants had failed a trial of medical management. Follow-up from 1 month to 5 years showed no intraoperative complications and resolution of symptoms in 91 per cent of our patients. Technical factors found to enhance the success of the operative repairs included appropriately sized dilators, division of the short gastric vessels, and a loose 360-degree wrap. With suitable technique, the surgical management of symptomatic GER can be performed safely in small infants.

Comparison of the diagnostic value of serum pancreatic isoamylase and immunoreactive trypsin measurement in patients with cystic fibrosis.

We have measured serum immunoreactive trypsin (IRT) and serum pancreatic isoamylase (PIA) activities using commercially available kits in 37 cystic fibrosis (CF) patients and 46 hospital controls of similar age range. Immunoreactive trypsin was more often abnormal than PIA (26/37 v 18/37 abnormal respectively); IRT will be particularly useful as an additional diagnostic test in older children, in whom interpretation of the sweat test may be difficult, as 14/15 CF patients aged over 10 years had abnormal IRT results. Less than half of our patients who were aged between one and nine years had abnormal IRT activity, limiting the value of the test, though a low activity would still support the diagnosis of CF. Comparison with faecal fat estimations in 31 patients suggests that neither IRT nor PIA can be used as a non-invasive test of pancreatic function in order to identify those few CF patients who do not require pancreatic enzyme supplements.

Engelmann's disease and the effect of corticosteroids. A case report.

A 13-year-old girl presented with a two-year history of pain in the right thigh and right forearm. Engelmann's disease was diagnosed on the basis of radiological appearances and histological examination of the bone. Her symptoms subsided after biopsy of the bone, but two weeks later she developed severe pain in the left tibia and was unable to walk. Radiological features of Engelmann's disease were found in the left tibia and other long bones although these bones had been radiologically normal one month previously. Treatment with prednisolone gave rapid relief of pain and allowed the patient to become mobile again. Four months later the radiological appearances showed significant improvement. The use of corticosteroids in this disorder is discussed.