Extended use of computed tomography in the management of complex aortic problems: a learning experience

Eighty-nine patients with clinical problems arising from the thoracic or abdominal aorta had computed tomography (CT) scans with contrast enhancement in addition to standard aortograms. Forty-four patients had aneurysms, 22 had aortic graft complications, and 23 had aortoiliac occlusion. CT scanning provided diagnostic information not apparent by conventional angiography in 39 patients (43.8%). This additional information did not significantly alter the operative management in 13 patients (14.6%). The helpful information provided by CT in these patients included demonstration of gallstones, renal cysts, anomalous venous structures, horseshoe kidney, and femoral anastomotic aneurysms. However, in 26 of 89 patients (29%), the additional data obtained by CT significantly changed the timing or approach to operative management. Management was altered in 12 of 44 patients (28%) with aneurysms, 7 of 22 patients (32%) with aortic graft complications, and 7 of 23 patients (30%) with aortoiliac occlusive disease or suspected distal thromboembolism. Specific information provided by CT included contained aortic aneurysm rupture, aortic dissection, laminated intraluminal thrombus or pseudointima, extent of perigraft infection, aortic atherosclerosis, anastomotic false aneurysm, and thrombus as a source of distal embolization. Thus, CT had a significant impact on operative management. It serves as a valuable adjunct to aortography in patients with complex aortic problems.

Descending thoracic aorta-to-femoral artery bypass

Descending thoracic aorta-to-femoral artery grafts were placed in 13 patients who had abdominal aortas deemed undesirable for surgical treatment. These included seven patients in whom an infected aortic graft had been removed for primary graft infection (three) or aortoduodenal fistula (four). These patients had been treated initially with axillary-femoral grafts. In five other patients, this approach was used following failure of at least two previous aortofemoral grafts. The remaining patient was so treated following multiple complex abdominal operations. The surgical technique involves a posterolateral, seventh interspace thoracoabdominal incision with a transdiaphragmatic retroperitoneal tunnel to the left groin. There was no operative mortality. The mean follow-up of all patients was 22 months (range, one to 44 months). All grafts remained patent except one, which was removed because of ascending groin infection. Three patients died, at 24, 29, and 44 months postoperatively, respectively. Reasonable perioperative morbidity and reliable patency make this an attractive technique for the conversion of axillofemoral bypasses and, when reentry of the abdominal cavity is undesirable, laparotomy is avoided.

Result of bypass grafting for upper limb ischemia

Bypass grafting in the treatment of upper extremity ischemia is required far less frequently than it is in the lower extremity. The present study was undertaken to evaluate functional results and long-term patency of such grafts. Between 1978 and 1984, 33 bypass grafts were performed to relieve hand and forearm ischemia in 27 patients. The indication for bypass was neglected trauma (violent or iatrogenic) in 12 cases, primary arteriopathy in nine patients, and vascular complications of thoracic outlet compression in six patients. A reversed saphenous vein graft was used in 22 cases, and polytetrafluoroethylene was used in the remaining 11 procedures. Proximal anastomoses were from the aortic arch (one), subclavian artery (five), axillary artery (11), carotid artery (seven), and brachial artery (nine). Distal reconstructions were to the subclavian (three), axillary (three), brachial (16), radial (four), ulnar (two), and interosseous (five) arteries. Complete pre- and postoperative Doppler pressure measurements were available in 19 cases and demonstrated a significant increase in forearm systemic pressure index, from 0.51 before bypass to 0.86 postoperatively (p less than 0.001). Finger systolic pressure measurement in 10 patients also showed a significant improvement after operation. Follow-up of 31 grafts from 6 to 72 months (mean, 35.5 months) revealed an overall patency rate of 73% at 2 years and 67% at 3 years. Similar to lower extremity revascularization, more proximal grafts fared better; the 2-year patency rate was 83% for grafts at or above the brachial artery but only 53% for bypass distal to the brachial bifurcation. Major amputation was not required in any case, even after graft occlusion.

Popliteal artery entrapment: diagnosis by computed tomography

Popliteal artery entrapment by an anomalous band of the gastrocnemius muscle is uncommon. In cases where popliteal artery occlusion has occurred, the diagnosis is difficult to establish. A case is presented in which computed axial tomography of the popliteal space established the diagnosis of popliteal artery thrombosis caused by entrapment when other diagnostic modalities were inconclusive. Computed axial tomography provides precise anatomic display of the muscle structure of the popliteal fossa and should be an important diagnostic tool in patients suspected to have popliteal artery entrapment.

Surgical treatment of venous obstruction and insufficiency

Direct venous reconstruction is being applied to patients with chronic venous stasis disease. Crosspubic bypass and saphenopopliteal bypass have proved to be satisfactory procedures whereas valve reconstructions by valvuloplasty, segment transfer, and autotransplantation are being explored. These procedures add to the surgeon's armamentarium in dealing with chronic venous stasis disease.

Smokeless tobacco use among adolescents: demographic differences, other substance use, and psychological correlates

Survey data on smokeless tobacco and other substance use were obtained from 2,926 seventh, ninth, and eleventh graders in Ventura County, California public schools. Patterns of smokeless tobacco use were examined relative to other drug use, particularly cigarette smoking. Few females used smokeless tobacco regularly, as compared to 4.7 percent of the males. The data supported the view that the recent increases in smokeless tobacco use were related to male tobacco users' belief that smokeless tobacco was less harmful to physical health than cigarette smoking. A Guttman scalogram analysis showed that tobacco use, either cigarette smoking or smokeless tobacco use, occurred after marijuana use rather than before. Perceived parental attitudes toward marijuana use predicted both cigarette smoking and use of smokeless tobacco, whereas perceived parental attitudes toward alcohol use was only related to use of cigarettes. Quality of life measures were inversely related to both cigarette smoking and smokeless tobacco use, but mood state measures predicted only cigarette smoking. Implications of the results for a historical hydraulic model of aggregate drug use are discussed with recommendations for improved approaches to the prevention of drug abuse.

Vascular anastomoses with laser energy

Laser-assisted arterial and venous anastomoses are now feasible. A microscope-guided CO2 laser was used to deliver 60 to 100 mW to anastomose end to end 44 rabbit carotid arteries (1.5 to 2.0 mm) and 27 rabbit vena cavae (4 to 6 mm). These were compared with control arteries repaired with interrupted suture technique. Anastomoses were examined from between 24 hours and 19 weeks. Laser carotid anastomoses yielded 93% patency (41 of 44) and 9% aneurysms (4 of 44), whereas hand-sewn carotid anastomoses produced 91% patency (40 of 44) and no aneurysms. In the vena cava, 26 of 27 laser anastomoses were patent (96%) compared with 19 of 20 (95%) sutured controls. Venous aneurysmal dilatation was seen in 2 of 27 laser (7%) and in 3 of 20 (15%) hand-sewn anastomoses. Histologic examination of laser-assisted anastomoses showed local full-thickness thermal injury. Repair was by fibroblast and myofibroblast proliferation, and luminal cell coverage was complete by 14 days in both laser and sutured repairs. Laser arterial and venous anastomoses are attractive because of their simplicity and rapidity of performance. Their patency is comparable to sutured anastomoses, but arterial aneurysms remain a hazard despite use of extremely low laser energy.

Intraoperative fine needle aspiration biopsy of thoracic lesions

Forty-one intraoperative fine needle aspiration biopsies were performed on 35 patients during exploratory thoracotomy (33 patients) or mediastinoscopy (2 patients). Each biopsy was done with a 22 gauge needle. Smears were prepared at the operating table, air-dried, sent directly to the laboratory, stained, and interpreted immediately by the pathologist. Preparation and reporting time averaged ten minutes. Surgical decisions were made on the basis of the pathologist's reports. Intraoperative fine needle aspiration biopsy was 100% accurate in differentiating inflammatory from neoplastic lesions. Ninety-five percent diagnostic accuracy for malignancy (39 out of 41 specimens) was obtained. It permitted quick biopsy of lesions deep within the lung parenchyma without the need to cut across uninvolved tissue, thus permitting appropriate resection in each patient. There were no deaths related to the procedure.

RNA polymerase activity of Amsacta moorei entomopox virions

Optimum conditions for in vitro RNA synthesis by the entomopoxvirus from Amsacta moorei, except for a temperature optimum of 26 degrees, were similar to those reported for vaccinia. Incorporation of 3H-ATP in the presence of CTP, GTP and UTP was significantly inhibited by actinomycin D; incorporation of 3H-ATP alone was not. The products formed by incorporation of 3H-ATP alone or with the three other nucleotides contained polyadenylic acid sequences. The sedimentation coefficient of the 3H-ATP-labeled product formed in the presence of CTP, GTP and UTP was reduced from 8-23S to 3-5S after RNase treatment. The product formed from 3H-ATP alone had an apparent sedimentation value of 3-5S.

Dissociation of ribosomes and seed germination

Ribosomes from rice embryos (Oryza sativa) were dissociated into ribosomal subunits in vitro by systematic reduction of the Mg(2+) concentration. Ribosomes from imbibed (28 C) embryos were more easily dissociated than those from nonimbibed embryos. This was not observed with ribosomes from either imbibed, nonviable embryos, or from embryos imbibed at 0 C. Ribosomes from embryos which had been imbided and subsequently dehydrated resembled ribosomes from nonimbibed embryos in their resistance to dissociation. The change in the resistance to dissociation was essentially complete after the first 20 minutes of imbibition at 28 C, and accompanied activation in vivo of protein synthesis as determined by amino acid incorporation in vitro. Ribosomes from either imbibed or nonimbibed embryos could be dissociated into subunits by 0.5 m KCl. These subunits were separated by density gradient centrifugation, and, if recombined, were active for polyphenylalanine synthesis in vitro. The individual subunits prepared from nonimbibed embryos could be replaced by the corresponding subunit fraction from imbibed embryos without loss of capacity to support polyphenylalanine synthesis. The change in the ease of dissociation of ribosomes appears to be a physiological process, and its possible relationship to the initiation of protein synthesis during seed germination is discussed.

Heat stabilities of acid phosphatases from pinto bean leaves

Two acid phosphatases were demonstrable by polyacrylamide gel electrophoresis. They had different mobilities and different heat stabilities in 1.0M acetate buffer, pH 5.2. Both phosphatases had the same electro-phoretic mobility in tris buffer at pH 7.5, gave one boundary in the analytical ultracentrifuge in tris or acetate buffer, and had the same sedimentation coefficient. The difference in these properties suggests an alteration in conformation of the proteins by the buffer systems.