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Biomedical subjects

M C Donaldson

Publications and source records attributed to M C Donaldson.

86 records · Page 5Linked to original sources
PubMed1985

Influence of anti-endothelial cell antibodies on the interactions of leukocytes with vascular endothelial cells in vitro.

The role of mononuclear cells in antibody-mediated endothelial cell damage and vascular diseases is not well understood when compared to our understanding of the role of neutrophil-mediated endothelial injury in vascular diseases. Thus we initiated these in-vitro studies to investigate the interactions of leukocytes (neutrophils and mononuclear cells) with vascular endothelial cells in the presence and absence of antiendothelial cell antibodies (anti-red blood cell antiserum-anti-RBC). Cultured endothelial cells were isolated from bovine pulmonary artery. The effects of unfractionated and fractionated human leukocytes (neutrophils, mononuclear cells, or lymphocytes) on endothelial cell viability was examined both quantitatively (51Cr release) and qualitatively (electron microscopy). Results from these studies indicated that the interactions of mononuclear cells and lymphocytes with antibody-coated endothelial cells resulted in a significant endothelial cell lysis within 1 to 6 hours of reactions. Neutrophils, on the other hand, failed to induce significant endothelial cell damage compared to mononuclear cells and lymphocytes when tested under similar conditions. In the absence of anti-RBC antibodies, all cell types (neutrophils, mononuclear cells, or lymphocytes) did not produce detectable endothelial damage. Additionally, the effectiveness of mononuclear cells to injure antibody-labeled endothelial cells was confirmed by ultrastructural examination. Similar studies, utilizing leukocytes obtained from patients with atherosclerosis disease, were also undertaken. In these studies we found that, again, only mononuclear cells and lymphocytes wer capable of inducing damage to endothelial cells precoated with antibodies. In summary, our results demonstrate the ability of mononuclear cells and lymphocytes to induce significant damage to antibody-coated endothelial cells. This finding suggests a major role of mononuclear leukocytes in vascular endothelial destruction in diseases that are characterized by the presence of circulating autoantibodies in serum and the adhesion of mononuclear cells to the vascular wall. Such diseases include vasculitis, allograft rejection, serum sickness, and perhaps atherosclerosis particularly in patients with autoimmune diseases.

Animals↗
PubMed1985

Factors affecting survival after ruptured abdominal aortic aneurysm.

To identify the factors affecting the high mortality rates associated with ruptured abdominal aortic aneurysm (AAA), a review was made of the records of 81 patients treated surgically between 1972 and 1983. Correlation of data with survival and predictive value of preoperative findings were studied. The mortality rate was 43.2%; there was a 29.2% mortality rate among those surviving the day of surgery. Patient-determined variables associated with deaths included age more than 76 years, hematocrit less than 30% and acute abnormality detected by ECG at admission, and suprarenal extension or free rupture of the AAA. Survival could be predicted with only 70% accuracy with a computerized discriminant function based on age and hematocrit and blood pressure values determined at admission. Events following admission associated with death were precipitous fall or persistently low level of preoperative blood pressure, technical complications, and postoperative organ failure. Although the patient's ultimate outcome after ruptured AAA is partly determined before intervention of the physician, efforts to address events resulting in death after admission by improving rapid diagnosis, early resuscitation, and prompt flawless surgery can increase survival.

Aged↗
PubMed1984

Lessons from initial experience with the in situ saphenous vein graft.

A policy of preference for the in situ saphenous vein was adopted for all patients requiring bypass grafting below the knee. In an initial series of 25 operations, technical complications occurred in eight cases (32%), including venographic extravasation, vein injury during valve lysis, and early graft occlusions due to incomplete valve lysis and routing under tension past the hamstring tendons. Early loss of tibial outflow vessels occurred twice, with retrieval of embolic debris possibly shed from the graft. In spite of these events, at an average follow-up of ten months, 21 grafts were open (84% patency). Two occlusions occurred in patients who suffered operative complications, and another graft was lost after rethrombosis of a donor axillobifemoral prosthesis. Acceptable patency in spite of technical mishaps early in my experience encourages continued efforts to master the in situ method.

Femoral Artery↗
PubMed1984

Effect of aspirin and dipyridamole on the patency of lower extremity bypass grafts.

Recent clinical studies indicate that the use of aspirin and dipyridamole improves graft patency rates in patients with infrainguinal polytetrafluoroethylene (PTFE) grafts and aortocoronary vein grafts. We undertook a prospective, double-blind, randomized study to determine whether these drugs administered postoperatively to patients with PTFE or autologous vein infrainguinal bypasses would improve graft patency during the first 24 months after operation. Patients received either aspirin 325 mg and dipyridamole 75 mg or identical placebo tablets three times a day, taken orally. Patency rates were compared by computing standard life tables and comparing cumulative patency rates. One hundred patients with 102 grafts were studied. The cumulative patency rate at 24 months was not significantly different for the treatment (57%) versus control (67%) groups or for any subgroup. We conclude that aspirin and dipyridamole administered postoperatively in the doses used in this study do not improve the overall patency rates of vein or PTFE infrainguinal bypass grafts.

Aged↗
PubMed1983

Surgery for acute carotid occlusion. Therapy in search of predictability.

Carotid thromboendarterectomy is rarely performed in the face of an acute, apparently nontransient neurologic deficit. However, clinical improvement may follow timely surgery. Because efficacy and safety remain unpredictable, operative therapy is denied to many patients who might benefit. We reviewed six illustrative cases and the clinical and experimental rationale for surgery in patients with an acute carotid occlusive neurologic deficit in hopes of stimulating renewed interest in refining criteria for selection of operative candidates.

Adult↗
PubMed1980

Femoropopliteal bypass grafting for intermittent claudication: is pessimism warranted?

From 1965 to 1979, 43 consecutive patients underwent 51 femoropopliteal reconstructions to relieve disabling claudication. This represented 17% of 298 femoropopliteal and femorotibial reconstructions performed by the same surgical team during this period of time. All patients operated on for claudication experienced relief of symptoms after surgery. There was no operative mortality and there was only one case of immediate graft failure. Cumulative graft patency was 93% at two years and 88% at five years by life table analysis. One patient who underwent below-knee amputation 12 years after his initial femoropopliteal graft was the only patient who lost a limb at any time during the follow-up period. On the basis of this experience, we now offer femoropopliteal grafting to any active individual who is disabled by intermittent claudication on the basis of superficial femoral artery occlusive disease.

Adult↗
PubMed1980

Thirty-year experience with surgical interruption of the inferior vena cava for prevention of pulmonary embolism.

Case records of 237 patients treated by inferior vena cava (IVC) ligation (154), suture plication (27) or clip application (56) were reviewed. Indications for surgery included failure of anticoagulation or femoral vein ligation to control embolism and threat of potentially massive, septic or paradoxical emboli. Overall hospital mortality was 15% and recent operative mortality was 2%. The incidence of early postoperative leg swelling was 36% and late venous sequellae occurred in 50% of the follow-up group of 140 cases followed an average of 44.3 months. Morbidity secondary to IVC interruption was decreased by use of the prosthetic lip, but clip application was still associated with early leg swelling in 21% and late mild swelling in 24%. The incidence of proven or suspected recurrent emboli was 7.6% with no significant variation by type of IVC procedure, and recurrent emboli were fatal in 2.5%. Refinement of indications, operative methods and perioperative care for IVC interruption procedures over the years has substantially improved the surgical approach to prevention of life-threatening pulmonary embolism.

Adolescent↗
PubMedDate not supplied

The blue scrotum sign of Bryant: a diagnostic clue to ruptured abdominal aortic aneurysm.

A 73-year-old man presented to the emergency department twice with nonspecific abdominal pain. He was diagnosed as having mild diverticulitis and was discharged. Four days later he presented to the emergency department in severe abdominal pain with scrotal and penile ecchymoses. After an initial urologic consultation the correct diagnosis of ruptured abdominal aortic aneurysm was made. We discuss the pathogenesis of the genital discoloration and make the correct historical attribution of this sign to John Henry Bryant, a turn-of-the-century physician at Guy's Hospital.

Aged↗
PubMedDate not supplied

Patency results of percutaneous and surgical revascularization for femoropopliteal arterial disease.

To estimate the patency results of percutaneous transluminal angioplasty and bypass surgery in the treatment of femoropopliteal arterial disease, a Medlars search of the English-language medical literature was performed. Inclusion required that studies 1) report original data, 2) report patency with a life table or Kaplan-Meier analysis with the number at risk or standard errors, 3) define patency as hemodynamic improvement, 4) report the distribution of covariates, and 5) not duplicate other published material. Using a method based on the proportional-hazards model and the actuarial life-table approach, the results were adjusted for differences in case-mix of the study populations and patency was predicted for subgroups at various levels of risk for failure. The unadjusted pooled life tables yielded five-year patencies of 45% (+/- 2%) for angioplasty, 73% (+/- 2%) for bypass surgery using a vein graft, and 49% (+/- 3%) for bypass surgery using a polytetrafluoroethylene graft. Adjusted five-year primary patencies after angioplasty varied from 12% to 68%, the best results being for patients with claudication and stenotic lesions. Adjusted five-year primary patencies after surgery varied from 33% to 80%, the best results being for saphenous vein bypass performed for claudication. The authors conclude that pooling life-table data without adjustment for covariates can be misleading. Indication, lesion type, vein graft availability, and site of the distal graft anastomosis need to be considered in predicting patency results of revascularization for femoropopliteal arterial disease.

Angioplasty, Balloon↗
PubMedDate not supplied

Arterial reconstruction for lower limb ischemia.

The treatment of advanced atherosclerosis involving the lower extremities has undergone considerable evolution over the last several decades. Current strategies hinge on an appreciation of the natural history of disease, the overall health status of the patient, and an armamentarium of endovascular and open surgical reconstructive techniques that may be tailored to optimize outcome for the individual patient. Patients with aorto-iliac disease have a variety of available options with generally good results. For infrainguinal disease, surgical bypass using autogenous vein is the mainstay of interventional therapy and will remain so for the foreseeable future. Increasing medical and surgical challenges are presented by this population, particularly as aggressive medical treatment of risk factors leads to an ongoing decline in cardiovascular mortality, combined with a dramatic increase in the prevalence of diabetes. The future, which is now already at hand, will bring the application of genomics, with a potential for altering the progression of disease as well as extending the long-term benefits of reconstruction.

Blood Vessel Prosthesis Implantation↗