John L. Glover

Seeding human arterial prostheses with mechanically derived endothelium *: The detrimental effect of smoking

Endothelial healing of Dacron arterial prostheses can be hastened in dogs by seeding autogenous venous endothelium onto the prostheses in a single-staged operation. To determine whether this technique enhances the patency of human grafts, we studied the results of 186 operations on 161 patients performed between February 23, 1978, and December 1, 1982. Alternately allocating patients to treatment with seeded and unseeded Dacron knitted prostheses, we performed axillary-femoral and axillary-femoral-femoral bypasses in 11 patients (six seeded and five unseeded) and femoral-femoral bypasses in 28 (13 seeded and 15 unseeded). By a randomized block method of treatment allocation, femoral-popliteal grafts were installed in 147 limbs (112 vein, 18 seeded, and 17 unseeded). Patency was analyzed by the life-table method. Overall, femoral-femoral and femoral-popliteal bypasses demonstrated no difference between the seeded and unseeded grafts. Patency was somewhat better in seeded than unseeded axillary-femoral bypasses. Nevertheless, nonsmokers with seeded femoral-popliteal Dacron grafts enjoyed a significantly better graft patency than those with unseeded grafts (p = 0.035), whereas a substantial deterioration of seeded Dacron grafts was observed in those patients who smoked (p = 0.008 at 6 months). Vein grafts performed better than either seeded or unseeded Dacron prostheses (p = 0.016). Serum beta-thromboglobulin (BTG) levels varied widely and did not differ among any of the treatment groups. We concluded that endothelial seeding improved the patency of human arterial prostheses but that results were worse if the patient was a smoker. BTG was not a useful measure of the platelet activation induced by an arterial prosthesis.

Enzymic imbalance in serine metabolism in human colon carcinoma and rat sarcoma

The activities of 3-phosphoglycerate dehydrogenase, an enzyme of serine biosynthesis, and serine hydroxymethyltransferase, serine dehydratase and serine aminotransferase, which are competing enzymes of serine utilization, were assayed in human colon carcinomas from patients and in transplantable rat sarcomas. Serine dehydratase and serine aminotransferase activities were absent, whereas 3-phosphoglycerate dehydrogenase and serine hydroxymethyltransferase activities were markedly increased in both tumour types. Serine hydroxymethyltransferase catalyses the formation of glycine and methylene tetrahydrofolate which are important precursors for nucleotide biosynthesis. The observed enzymic imbalance in these tumours ensures that an increased capacity for the synthesis of serine is coupled to its utilisation for nucleotide biosynthesis as a part of the biochemical commitment to cellular replication in cancer cells. That this pattern is found in sarcomas and carcinomas, and in tumours of human and rodent origin, signifies its universal importance for the biochemistry of the cancer cell and singles it out as a potential target site for anti-cancer chemotherapy.

Endothelium develops on seeded human arterial prosthesis: A brief clinical note

Despite a considerable and growing body of evidence that endothelial cell seeding accelerates the healing of arterial prostheses in laboratory animals, there has been no histologic evidence thus far to indicate that a similar process occurs in human beings. A case is reported of histologically confirmed, extensive endothelial healing on a polytetrafluoroethylene femoropopliteal bypass graft 90 days after it was seeded and implanted.

Seeding endothelium on canine arterial prostheses--the size of the inoculum.

Nineteen dogs were studied to determine the minimum length of saphenous vein which will yield sufficient endothelium to line arterial prostheses interposed in the infrarenal aorta. Knitted Dacron grafts preclotted by the Sauvage technique were seeded by endothelial cells mechanically harvested from lengths of autogenous saphenous vein varying from 3 to 150 mm. After 1 month, the grafts were removed; the percentage of clot-free surface was determined; the inner surface area of the grafts was calculated (Ag), and the linings were examined histologically. The inner surface areas of the donor vein (Av) and the installed graft (Ag) were computed. The percentage of clot-free surface was 87.6 ± 9.4 in dogs in which the ratio of the area of the vein to that of the graft (Av/Ag) was greater than 0.425 as compared to 25.9 ± 25.9 in others (P 0.425 had thinner inner capsules (217 ± 99 versus 480 ± 222 μm, P < 0.0005). We conclude that the amount of venous surface necessary to provide endothelium to line an arterial prosthesis using these techniques is slightly less than half the area of the graft to be lined. The size of undistributed venous endothelial cells was used to calculate the expected cell yield. In nine additional dogs the number of endothelial cells in the suspensions were compared to Av. If all cells were harvested and seeded successfully, the Av/Ag ratio might be lowered from 0.425 to 0.031.

Patency in canine inferior vena cava grafting: Effects of graft material, size, and endothelial seeding

We studied 117 inferior vena cava (IVC) replacements in dogs to determine the effects of graft material, graft size, endothelial seeding, and cultured endothelial linings on graft patency. As a control, the IVC was removed and reimplanted in 11 dogs. Dacron (n = 7) and expanded polytetrafluoroethylene (e-PTFE) grafts (n = 12) were seeded immediately with the use of enzymatically derived autogenous jugular vein endothelium. Cultured linings were prepared for e-PTFE grafts (n = 9) by inoculating the graft with jugular endothelium and nurturing the lining in tissue culture for 14 to 30 days before implantation. Unseeded grafts (n = 27) were prepared according to the manufacturers recommendations. These six methods of preparation were tested in grafts measuring 6 mm I.D. and 60 mm in length. Other sizes were tested with a Latin square study design. After 30 to 60 days the grafts were perfusion fixed and studied with light and transmission electron microscopy. Patency was determined by contrast cavography after 7 and 30 days. Patency in the IVC reimplantation was 100% compared with 28.0% of the e-PTFE (p = 0.001) and none of the Dacron grafts that measured 6 mm I.D. and 60 mm long. e-PTFE and Dacron graft patency also differed significantly (p = 0.035). Seeded and culture-lined e-PTFE grafts in that same size were patent in 31.6% compared with 16.7% of unseeded e-PTFE. With grafts measuring 80 mm long, three of the five e-PTFE grafts were patent between 3 and 7 days. All progressed to occlusion by 30 days and compared poorly with all other graft sizes tested (2.6% progression to occlusion [p = 3 X 10(-8)]). Recanalization was not seen in 10 occluded grafts that were followed for 60 days. The histologic features of seeded grafts differed remarkably from grafts previously studied in the arterial circulation and from culture-lined and unseeded venous prostheses in that 60% had prominent large, random, endothelium-lined channels within the inner capsule. Larger graft diameters (p = 0.009) and the omission of an endothelial surface treatment (p = 0.004) were associated with anastomotic subendothelial fibrous hyperplasia. We conclude that graft material is the major determinant of patency in IVC replacements, that an extensive endothelial surface promotes patency, but that simply seeding e-PTFE or Dacron grafts with 10(5) endothelial cells does not provide sufficient endothelium to alter early patency.(ABSTRACT TRUNCATED AT 400 WORDS)

Leukocyte depletion enhances cultured endothelial retention on vascular prostheses

Approximately 90% of endothelial cells that are seeded or cultured onto vascular prostheses are lost from the flow surface within 24 hours of implantation. To determine the contribution of leukocytes to endothelial cell loss, 111In-labeled, cultured canine jugular venous endothelial cells were grown to confluence on fibronectin-coated polyester elastomer tubes measuring 4 mm inner diameter and 30 mm in length. Autogenous cell-lined tubes were implanted as bilateral carotid replacement grafts in six dogs made leukopenic by cyclophosphamide. Similar unilateral grafts were placed in 12 control dogs. Grafts were removed and perfusion-fixed from six control animals after 2 hours of in vivo arterial perfusion and from the other six animals after 6 hours of perfusion. One graft was removed and perfusion-fixed from each leukopenic animal after 2 hours of implantation and the other after 6 hours. Attachment of endothelial cells to the grafts was measured by indium-labeling technique. Retention of endothelium on grafts removed after 2 hours was measured by planimetric counting with scanning electron microscopy and on those removed after 6 hours by radioisotope quantification. Endothelial cell retention after 2 hours was 37.6% +/- 27.0% in control dogs and 97.0% +/- 3.4% in leukopenic animals (p less than 0.0007). After 6 hours retention was 35.9% +/- 23.2% in control animals and 86.5% +/- 6.0% in leukopenic animals (p less than 0.0009). Leukocyte surface activity was present in less than 1% of the leukopenic dogs compared with 8.5% of the other in vivo midgrafts after 2 hours. These results suggest that leukocytes play a significant role in the loss of seeded endothelium from vascular prostheses.

Autotransfusion of contaminated intraperitoneal blood: an experimental study.

Contamination of blood by bowel contents has been generally assumed as an absolute contraindication to autotransfusion. Since abdominal trauma is frequently accompanied by bowel injury and massive blood loss, a potential major use for autotransfusion has thus been precluded. To test this presumption, autologous blood grossly contaminated with feces was incubated in the peritoneal cavity and then autotransfused in dogs. The animals were hemorrhaged 20, 30, or 40% of their estimated blood volume, producing mild to severe hypovolemic shock. Reinfusion of contaminated blood had little effect on survival with 20 or 30% hemorrhage, but contamination markedly decreased survival with 40% hemorrhage:90% survived without contamination while only 30% survived with contamination. The use of antibiotics in a similar group of dogs subjected to 40% hemorrhage essentially eliminated the risk of autotransfusion: 90% of these dogs survived autotransfusion of contaminated blood.

Clotting competence of intracavitary blood in trauma victims

In order to assess more rationally the requirement for anticoagulation during intraoperative autotransfusion, the clotting competence of blood collected from the body cavities of 31 trauma victims entering our emergency department with indications for intraoperative transfusion was assessed. Blood was collected at thoracotomy or laparotomy prior to the institution of any anticoagulant measures and was assessed for clotting competence, the presence of fibrinogen, the presence of soluble fibrin monomere, and the appearance of fibrin degradation products. The prothrombin time, partial thromboplastin time, and thrombin time of this blood were markedly elevated; fibrinogen was absent; soluble fibrin monomer was absent; and fibrin degradation products were markedly elevated. Blood collected from body cavities is then incoagulable, and we suggest that in the autotransfusion of such a product the need for anticoagulation may be reduced.

Autotransfusion of blood contaminated by intestinal contents

In a series of 183 emergency operations in which intraoperative autotransfusion was used, 14 patients received blood contaminated by intestinal contents. Six of the 14 patients died early in the postoperative period, four of whom had received more than 16 liters of blood. Only two of the eight survivors had received comparable amounts of blood (13 and 17.5 liters). All eight received antibiotics upon admission; four had positive blood cultures within 24 hours of operation. Complications included acute tubular necrosis in three patients and bowel obstruction with intra-abdominal abscess in another. One of the patients with acute tubular necrosis died six weeks later; all others recovered. We believe this procedure may be life-saving in some cases.

Primary versus delayed-primary neurorrhaphy in rat sciatic nerve

INTRODUCTION The histological aspects of nerve degeneration and regeneration have been extensively studied by light and electron microscopy and the results have been reviewed by several authors [5, 7, 11, 171. Despite the large volume of literature on regeneration, however, the timing of nerve repairs continues to be controversial. Grabb has demonstrated that primary is superior to secondary repair in monkeys [4]; Ducker advocates nerve repair after a 2to 3-wk delay; and Millesi’s report on nerve grafting has altered many neurorrhaphy principles [7]. In an attempt to assess differences between primary and delayed-primary neurorrhaphy, an experiment in which the timing of neurorrhaphy is the only major variable has been designed.