Endothelial seeding of venous prostheses.

To evaluate the potential benefit of endothelial seeding of venous prostheses, 20 dogs were subjected to iliocaval reconstruction with expanded polytetrafluoroethylene grafts protected by an arteriovenous fistula. Grafts seeded with enzymatically derived endothelial cells were compared with control grafts that were sham seeded with culture medium and blood. Five seeded and seven sham-seeded grafts remained patient and were perfusion fixed in situ 4 to 6 weeks after operation.

Platelet deposition on and calcification of bovine pericardial valve.

Platelet deposition on bovine pericardial mitral valves was quantified in healthy adult mongrel dogs at 1, 14 and 30 days post-implantation and 24 h after i.v. injection of 400-500 microCi of autologous 111In-platelets.

Overcoming failure of venous vascular prostheses.

Thrombogenicity of graft material, low velocity of blood flow, and wall collapsibility have been cited as the main factors responsible for the high occlusion rate of vascular prostheses placed in the venous system. This study was performed to analyze the effects of measures taken to overcome each of these factors. The thrombogenicity of expanded polytetrafluoroethylene (ePTFE) was evaluated by determination of the 3-hour deposition of radionuclide-labeled platelets and fibrin on grafts placed in the infrarenal vena cava of 18 dogs.

Splenic torsion. An unusual cause of splenomegaly.

A 28-year-old woman who presented with acute abdominal pain and splenomegaly was found to have little functioning splenic tissue on liver-spleen scan but a large homogeneous spleen by computerized axial tomography. Laparotomy revealed torsion of the splenic pedicle and extensive splenic infarction. The presentation, pathophysiology, and diagnostic difficulties of this case are discussed.

The permanence of the visual recovery that follows reverse occlusion of monocularly deprived kittens.

While the behavioral and physiologic effects of an early period of monocular deprivation can be extremely severe, they are not necessarily irreversible. Considerable recovery can occur if visual input is restored to the deprived eye sufficiently early, particularly if the nondeprived eye is occluded at the same time (reverse occlusion). This study examines the permanence of the visual recovery promoted by a period of reverse occlusion in kittens that were monocularly deprived from near birth for periods ranging from 3 to 18 weeks.

Recurrent hemorrhage into the pancreatic duct from a splenic artery aneurysm.

We describe a case of upper gastrointestinal hemorrhage secondary to splenic artery aneurysm-pancreatic duct fistula, with associated partial common bile duct obstruction and pancreatitis. The literature is reviewed briefly in order to stress distinctive clinical features and caveats in diagnosis. Angiography is the most definitive diagnostic study; surgical resection is curative.

Morphologic quantitation of pseudointima and effects of antiplatelet drugs on vascular prostheses in goats.

The natural process of endothelialization, pseudointimal formation, and connective tissue incorporation of the expanded PTFE grafts in the goat was documented through histologic examination of specimens harvested at 2, 4, 6, and 8 weeks. The goats demonstrated a progressive increase in pseudointimal pannus ingrowth from the anastomoses at a rate of 11.3 mm over a 12 week period.

The effect of preclotting on surface thrombogenicity and thromboembolic complications of Dacron grafts in the canine thoracic aorta.

Previous reports have advocated preclotting and autoclaving of Dacron grafts to prevent graft hemorrhage, yet no data delineate possible changes in surface thrombogenicity or thromboembolic risks. To assess these factors, preclotted and preclotted-autoclaved woven Dacron prostheses were implanted in the thoracic aorta of 31 dogs. Grafts were harvested 1 week to 1 month following implantation, and the thrombus-free surface of each graft was calculated by computerized morphometry.

Ibuprofen in experimental vascular surgery.

Animal studies have been conducted to determine the effectiveness of ibuprofen in reducing early platelet deposition on small diameter (4 mm) Gore-Tex (polytetrafluoroethylene) arterial grafts and larger (10 mm) Gore-Tex grafts placed in the inferior vena cava. These studies demonstrated a significant reduction in platelet deposition at one and three hours. Additional studies of animals undergoing treatment with ibuprofen and subjected to arterial replacement with 1 or 4 mm Gore-Tex grafts demonstrated enhanced patency at 30 days.

Experimental replacement of the inferior vena cava: factors affecting patency.

To evaluate factors influencing graft patency in the venous system, we replaced the inferior vena cava (IVC) in 50 dogs. Expanded polytetrafluoroethylene ( ePTFE ) grafts with external support were implanted into 32 animals while autogenous, spiral jugular vein grafts were used to replace the IVC in 18 dogs. 111In-labeled autologous platelets and 125I-labeled canine fibrinogen were utilized to evaluate early thrombus formation.

Toxic megacolon associated with methotrexate therapy.

We describe the case of a patient with psoriasis who developed severe colitis, with toxic megacolon, after a course of treatment with methotrexate. The duration of her colitis, which was eventually resolved by using conservative measures, was far greater than that of other drug-related complications, which included bone marrow depression, jaundice, and renal failure. The literature pertaining to this rare manifestation of methotrexate toxicity is reviewed.

When is it an osteoclast?

Using acid phosphatase as a marker, osteoclasts were examined from single sections of undemineralised iliac crest biopsies from patients with renal failure and from normal controls. Eighty one per cent of the cells from controls and 56% of the cells from patients with renal failure appeared to be non-nucleated or mononucleated. Serial sections showed, however, that 73% of the control cells were actually multinucleated as were 91% of the patients' cells.

Quantitative evaluation of ibuprofen treatment on thrombogenicity of expanded polytetrafluoroethylene vascular grafts.

To evaluate the effect of ibuprofen on graft thrombogenicity and early patency, expanded polytetrafluoroethylene (ePTFE) (Gore-tex) grafts with an inside diameter of 4 mm and length of 5 cm were implanted into the femoral artery in 43 dogs. Autogenous vein bypass was performed on the contralateral side. 111In-labeled platelets were injected into 16 dogs 24 hours prior to operation, and eight of these received 12.

Quantification of platelet retention in aortocoronary femoral vein bypass graft in dogs treated with dipyridamole and aspirin.

Autologous femoral vein segments were implanted as aortocoronary bypass grafts in 50 dogs, 25 of which were treated with dipyridamole and aspirin to inhibit platelet deposition and 25 that were not. Autologous platelets labeled with indium-111 were injected into some dogs 48 hr before they were killed on the first day after surgery; other dogs were injected 24 hr before they were killed (3, 7, 30, and 90 days after surgery). Radioactivity on the grafts and on control specimens of contralateral femoral veins was converted to quantification of platelets adhering to the vessel wall (platelets/cm2).

A new technique for producing pure aortic stenosis in animals.

To date, techniques used to produce an animal model of valvular aortic stenosis have been unsuccessful. We have developed a new technique for producing pure subcoronary aortic valvular stenosis, which results in left ventricular hypertrophy in a short time. Five adult mongrel dogs weighing 18-24 kg were anesthetized with Brevital (0.

Reasons for drinking: motivational patterns and alcohol use among college students.

A principal components factor analysis of survey data from 393 college student drinkers (178 males) extracted four dimensions from a set of 16 reasons for drinking: avoidance, social, sensation seeking, and enjoyment. Motivational patterns and the relationships with alcohol use were examined with a canonical correlation analysis. Three significant canonical variates were found.

Labile nature of the visual recovery promoted by reverse occlusion in monocularly deprived kittens.

Kittens were monocularly deprived by closing one eye at the time of natural eye opening for periods that ranged from 4 to 14 weeks. This eye was then opened, and the other eye was closed for an approximately equal period of time. During this period of reverse occlusion, the vision of the initially deprived eye improved from apparent blindness to a level of good visual acuity.

Prolonged dialyzer reuse.

Clearance of urea, creatinine, phosphate and B12 in dialyzers reused up to 30 times were unchanged from the initial values. Residual formalin values were within acceptable levels and in several thousand dialyses no untoward reactions of any sort attributable to reuse were encountered. Neutropenia was constantly present with dialyzers prepared by automated reuse.

Hemodialysis neutropenia and dialyzer reuse: role of the cleansing agent.

As part of a study to evaluate the safety and efficacy of dialyzer reuse, a comparative study of two methods of dialyzer reprocessing, manual and automated, was conducted. Five stable end-stage renal disease patients on center hemodialysis were evaluated as to hematological and metabolic parameters throughout two series of three consecutive dialyses using first new and then reused dialyzers reprocessed according to each of the two methods. New dialyzers and reused dialyzers following automated reprocessing always induced a profound fall in circulating neutrophil counts shortly after the start of dialysis.

Immediate and long-term effects on visual acuity of surgically induced strabismus in kittens.

In order to isolate some of the factors responsible for strabismic amblyopia as well as to ascertain the time course of its development, frequent measurements were made of the visual acuity of the two eyes of kittens following imposition of surgically induced strabismus. Following behavioural training on a jumping stand, strabismus was induced in all but one animal by simple section of either the lateral (esotropia) or medial (exotropia) rectus muscle of one eye. The one exception was a kitten on which esotropia was induced by another common but more radical surgical procedure that involved removal of the body of both the lateral rectus and superior oblique muscles of one eye.

Light and electron microscopic evaluation of canine hearts orthotopically transplanted after 24 hours of extracorporeal preservation.

The hearts of 19 dogs were subjected to in vitro, moderately hypothermic, whole blood perfusion through the aorta for 24 hours. Sixteen of the hearts were reimplanted into recipient animals in the conventional orthotopic fashion and three were subjected to histologic study without reimplantation. Fourteen of the 16 reimplanted hearts successfully supported the recipients.

Bone marrow aluminium storage in renal failure.

Using the staining method for aluminium with the ammonium salt of aurine tricarboxylic acid, aluminon, 18 patients with end stage renal disease gave positive reactions in iliac crest bone biopsies and 11 of these had positive staining in the bone marrow. In one the marrow was positive and the bone negative. The marrow reaction is putatively regarded as caused by aluminium storage in unidentified cells, possibly of the macrophage system which are strongly fluorescent when examined after prior tetracycline labelling.