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Biomedical subjects

C G Tribble

Publications and source records attributed to C G Tribble.

At least 19 recordsLinked to original sources
PubMed1992

Reduced-size porcine lung transplantation: long-term studies of pulmonary vascular resistance.

The use of isolated adult lobes for pediatric lung transplantation has recently been reported and could potentially help alleviate the profound pediatric donor lung shortage. However, the effect of chronic denervation on pulmonary vasculature of isolated mature lobar transplants is not well understood. Previously, we reported that chronic denervation of the immature porcine lobe results in abnormal pulmonary vascular compliance. We now present studies of long-term pulmonary hemodynamics in young pigs 12 weeks after transplantation of a reduced-size mature left lower lobe. Resting pulmonary vascular resistance of the transplanted mature lobes was similar to that of innervated lobes of age-matched controls. In addition, pulmonary vascular resistance of the transplanted mature lobes did not rise abnormally in response to increased flow caused by clamping the contralateral pulmonary artery. We conclude that denervation of the mature porcine lobe does not result in abnormal pulmonary vascular resistance. In addition, vascular compliance of reduced-size mature porcine lobar transplants is superior to that of denervated reimplanted immature lobes. These findings suggest a deleterious effect of denervation on pulmonary vascular development of the growing porcine lung.

Animals↗
PubMed1992

Transhiatal esophagectomy: a safe alternative for selected patients.

One hundred one consecutive patients underwent an esophagectomy with gastric interposition for benign and malignant processes from January 1982 through July 1990. Seventy-seven underwent transhiatal esophagectomy and 24, transthoracic esophagectomy. Multivariate analysis was performed comparing the hospitalization experience of the two groups. There was no significant difference found between the mean intraoperative blood loss for transhiatal esophagectomy (770 +/- 105 mL) and that of transthoracic esophagectomy (700 +/- 175 mL). There was a significant difference between operative time, with transhiatal esophagectomy averaging 5.4 hours and transthoracic esophagectomy averaging 7.3 hours. Postoperative stay was not significantly different although there was a wide range of values for the transthoracic esophagectomy group. An 8% operative mortality was experienced by both groups. There were a significant number of minor anastomotic leaks at the cervical anastomotic level for the transhiatal esophagectomy group, but all responded to nonoperative management. The highest morbidity and mortality were seen in the subgroup of transhiatal esophagectomies done for laryngocervical malignancies. The lowest morbidity and mortality were seen in the subgroup of 12 patients who underwent transhiatal esophagectomy for nonmalignant esophageal conditions. Transhiatal esophagectomy appears to be a safe alternative for early intrathoracic esophageal malignancies at any level, for bulky distal esophageal lesions, and for benign conditions requiring total esophagectomy.

Blood Loss, Surgical↗
PubMed1992

Successful treatment of postoperative chylothorax using an external pleuroperitoneal shunt.

We report 3 patients with chylothorax who were successfully managed as outpatients using external pleuroperitoneal shunts. This external shunt has the advantage over subcutaneously placed shunts of pumping large volumes of fluid with each compression of the pumping chamber, of not causing the discomfort associated with pumping a subcutaneous chamber, of not becoming difficult to find in the subcutaneous space, and of being constructed of larger components which do not kink or become easily clogged with fibrinous debris.

Adult↗
PubMed1992

Effect of adenosine deaminase on cardiac interstitial adenosine.

Adenosine deaminase was infused into isolated perfused guinea pig hearts to determine its effect on myocardial adenosine levels. The enzyme was administered during constant coronary flow perfusion at 6.11 +/- 0.36 ml.min-1.g-1. Venous adenosine was measured in samples of pulmonary artery effluent; epicardial and endocardial adenosine were measured with the porous nylon disk technique. Infusion of adenosine deaminase at 2.4 and 4.8 U/ml produced adenosine deaminase activity of 0.92 +/- 0.09 and 2.33 +/- 0.15 U/ml, respectively, in epicardial fluid and 1.93 +/- 0.28 and 4.84 +/- 0.47 U/ml, respectively, in endocardial fluid. Aortic pressure was unchanged by infusion of adenosine deaminase at both infusion rates. Adenosine deaminase (data from both infusion rates pooled) reduced epicardial adenosine from 0.327 +/- 0.028 to 0.139 +/- 0.022 microM, endocardial adenosine from 4.61 +/- 0.42 to 1.64 +/- 0.20 microM, and venous adenosine from 0.017 +/- 0.02 to 0.003 +/- 0.001 microM. The data indicate that infused adenosine deaminase reaches the epicardial and endocardial interstitial fluid (ISF) compartments. The absence of any effect on coronary pressure suggests that adenosine may not be involved in resting basal coronary tone. The presence of significant residual adenosine despite adenosine deaminase infusion indicates that adenosine production in the unstressed isolated guinea pig heart exceeds the degradative capacity of infused adenosine deaminase. Previous studies in which it was assumed that almost all of the endogenous adenosine is inactivated by the infusion of adenosine deaminase should be reevaluated in light of these observations.

Adenosine↗
PubMed1992

Effects of in vivo cyclosporine administration on endothelium-dependent responses in isolated vascular rings.

BACKGROUND: Although in vitro studies suggest that cyclosporine (CSA) reduces endothelium-dependent relaxation (EDR), controversy still remains regarding the effects of in vivo CSA treatment. The lack of correlation between CSA dosages and therapeutic efficacy has led to an increased emphasis on the monitoring of CSA blood levels in clinical immunosuppression. We therefore studied the effects of in vivo administration to rats of a therapeutic level of CSA on endothelium-dependent vascular reactivity using isolated vascular rings obtained from these animals. METHODS AND RESULTS: Thoracic aorta vascular rings from adult Sprague-Dawley rats treated with subcutaneous injections of CSA (5 mg/kg/day) for 7 and 21 days were suspended in Krebs buffer containing indomethacin and tested for EDR to methacholine (1 x 10(-7) to 5 x 10(-5) M) and for endothelium-independent relaxation (EIR) to nitroprusside (5 x 10(-6) M). Mean whole blood CSA trough levels were 978 +/- 287 and 2,865 +/- 379 ng/ml for the 7- and 21-day groups, respectively. No differences were noted in both EDR and EIR between untreated control rats and the treated groups. Maximal EDR (mean +/- SEM) was 83 +/- 3%, 79 +/- 2%, and 81 +/- 3% for control rats and 7- and 21-day treatment groups, respectively. Relative developed tension (grams) to 5 x 10(-6) M phenylephrine was significantly (p < 0.05) increased in the CSA-treated groups (1.03 +/- 0.01 and 1.08 +/- 0.01 g at 7 and 21 days, respectively, versus 0.73 +/- 0.01 g (p = NS) for untreated controls). Minimal endothelial disruption was evident on scanning electron microscopy in the CSA-treated animals. CONCLUSIONS: We conclude that CSA-induced vascular dysfunction may be in part a result of an increased sensitivity to direct vasoconstriction rather than of an attenuation of endothelium-dependent relaxation.

Animals↗
PubMed1992

Growth potential of porcine reduced-size mature pulmonary lobar transplants.

The use of mature pulmonary lobes for pediatric lung transplantation has recently been described. Successful application of this technique could help alleviate the pediatric donor lung shortage. Whether an already mature lobe can grow by forming new alveolar units after transplantation into a developing recipient is not known. We therefore measured functional residual capacity, fixed lung volume and weight, alveolar size and air space volume percent, and total number of alveoli in mature left lower lobe porcine lung transplants 12 weeks after transplantation into growing piglets. Comparisons were made with nontransplanted mature left lower lobes to determine if functional or morphologic growth had occurred after transplantation. The transplanted and control lobes were all taken from 6-month-old animals (mean body weight 105 +/- 4 kg). Recipients of the transplanted lobes were 9 weeks old and weighed 22 +/- 2 kg. By the end of the 12-week holding period, the recipient animals increased their body weight approximately fourfold (85 +/- 4 kg). No significant differences were seen in functional residual capacity or morphologic analysis of total alveolar number and alveolar size between the transplanted and nontransplanted lobes (p = not significant). Although the reduced-size mature porcine lobar transplants did not display a significant increase in either functional residual capacity or total alveolar number, there was significant growth of the transplanted mature lobes as determined by fixed volume and total lobar weight (p < or = 0.05 versus control animals).

Animals↗
PubMed1992

The cardiac illness of General Robert E. Lee.

We believe that General Robert E. Lee had ischemic heart disease. It is our opinion that he sustained a heart attack in 1863 and that this illness had a major influence on the battle of Gettysburg. Lee experienced relatively good health from 1864 to 1867, but by 1869 he had exertional angina and by the spring of 1870 had intermittent rest angina. Although his symptoms were typical of angina, his physicians consistently diagnosed pericarditis, which we believe was erroneous. This misdiagnosis can be explained by the lack of familiarity of American physicians with angina during the 19th Century. It often was stated that the loss of the war broke the heart of Lee, but in view of our modern day understanding, it probably is more accurate to say that advancing coronary atherosclerosis was the culprit.

Famous Persons↗
PubMed1992

A new, compound-curved needle for vascular surgery.

A new, compound-curved needle has been designed and developed for vascular surgery from a unique stainless steel alloy, American Society for Testing Materials (ASTM) 45500. This needle has two different radii of curvature and a relatively straight body followed by a short, curved tapered point. Despite its geometry, it exhibits a similar sharpness, as well as resistance to bending and breakage, as did a curved needle with a single radius of curvature manufactured from the same alloy. The design of this new needle enabled the surgeon to pass it through the vessel wall with greater accuracy to a controlled depth and length of bite than the curved cutting edge needle with a single radius of curvature.

Biomechanical Phenomena↗
PubMed1991

Weight is not an accurate criterion for adult cardiac transplant size matching.

Owing to the limited availability of donor hearts, standard donor criteria for heart size matching need to be reexamined. The current practice at most centers is to match the donor's body weight to within +/- 20% of the recipient's. Our hypothesis was that minimal differences exist in heart sizes of the adult donor population, and therefore, the donor pool could be expanded for any given patient. M-mode echocardiographic measurements of left and right ventricular internal dimensions, left ventricular mass, and percent fractional shortening were reviewed in 235 normal adult subjects (101 men, 134 women). Low correlation coefficients and a high degree of variance were consistently observed between cardiac parameters and body size. There were no significant differences in left ventricular internal dimension when women weighing 40 to 109 kg were compared with men statistically different among men weighing 50 to 99 kg. No difference was noted in right ventricular size among men and women. Echocardiography is a simple and accurate technique to assess cardiac dimensions. Body weight does not correlate well with adult cardiac size and should not be used as an exclusion criterion for a donor heart.

Body Height↗
PubMed1991

Denervation of transplanted porcine lung causes airway obstruction.

Lung transplantation can be complicated by a form of small airway obstruction known as bronchiolitis obliterans. We tested the hypothesis that lung denervation causes small airway obstruction in young pigs (10 +/- 1 weeks). Control pigs had an innervated native lobe, and study pigs had either a denervated native lobe or a denervated transplant lobe. Transplanted pigs received standard immunosuppression. At 10 weeks we measured isolated left lobe pulmonary mechanics. Dynamic resistance in both study groups was significantly higher than in the lobectomy group, whereas dynamic compliance in both study groups was significantly lower than in the lobectomy group. No significant difference in resistance or compliance was noted between the transplant and reimplant groups. Histologic changes consistent with rejection were noted in the transplant lobes. We conclude that the small airway obstruction noted in this model is due to operative denervation rather than to immunosuppression or rejection.

Animals↗
PubMed1991

Reducing postischemic paraplegia using conjugated superoxide dismutase.

Paraplegia after thoracic aortic aneurysm repair has an incidence of 2.2% to 24%. Oxygen-derived free radicals after reperfusion of an ischemic spinal cord may be partly responsible for neuronal destruction. We studied the effects of polyethylene glycol-conjugated superoxide dismutase (PEG-SOD), a free radical scavenger, as a way of increasing spinal cord tolerance to ischemia. Thirty rabbits underwent 40 minutes of aortic occlusion (a known model of paraplegia). Ten of these animals received 25,000 U/kg of PEG-SOD 24 hours before aortic occlusion and two additional doses of 10,000 U/kg, one before and one subsequent to spinal ischemia. Ten animals received superoxide dismutase in the same dosages as those receiving PEG-SOD. Ten control animals received placebo. All animals were studied for 96 hours, at which time a final neurological examination was performed and the results were recorded. Of the 10 animals treated with PEG-SOD, 2 were completely paralyzed whereas 8 had less (7) or no (1) neurological impairment. Eight of the 10 control animals and 9 of the 10 animals receiving superoxide dismutase were completely paralyzed. None of the control animals or animals receiving superoxide dismutase had a normal neurological examination (p less than or equal to 0.05). Treatment with PEG-SOD before and during occlusion increased the rabbit spinal cord tolerance to a 40-minute ischemic insult. Scavenging free radicals may lessen experimental spinal cord injury.

Animals↗
PubMed1991

The risk of axillofemoral bypass grafting for acute vascular occlusion.

The hypothesis of the present study is that axillofemoral bypass grafting for acute vascular occlusion has results significantly inferior to an elective procedure. We reviewed 53 patients undergoing primary axillofemoral bypass grafting at the University of Virginia from 1984 to 1989. We found that patients who were admitted with acute vascular occlusion had a higher incidence of perioperative complications (63% vs 26%, p = 0.001), perioperative mortality (26% vs 3%, p less than 0.05), lower graft patency at 1 year (60% vs 90%, p less than 0.05), lower rate of freedom from reoperation in first year (50% vs 82%, p less than 0.01), and lower rates of limb salvage (76% vs 94%, p less than 0.05) than patients undergoing axillofemoral bypass grafting for chronic symptoms or conditions. These two groups did not differ in any of the other risk factors or perioperative characteristics examined. We conclude axillofemoral bypass grafting performed for indications other than acute vascular occlusion is associated with acceptable morbidity, mortality, graft patency, and limb salvage rates.

Acute Disease↗
PubMed1991

The influence of preoperative radiation therapy on morbidity and mortality for transhiatal esophagectomy.

To assess the morbidity and mortality of preoperative radiation therapy (RT), the authors reviewed 37 consecutive patients who underwent transhiatal esophagectomy for carcinoma of the esophagus. Twelve patients received no RT, 13 patients received RT only to the neck, and 12 received RT to the chest (three of these received radiation therapy to the chest and neck). Preoperative chest RT did not significantly increase postoperative fistula formation but was associated with significantly higher operative mortality, overall complication rate, and time on ventilators than either the patients receiving neck RT alone or no RT (P less than 0.05). Postoperative hospital stay was longer and intraoperative blood loss greater for the chest RT group compared to those with no RT (P less than 0.05). Neck RT did not result in these complications (P = NS). The authors conclude that preoperative chest RT is associated with significant postoperative morbidity and mortality.

Adult↗
PubMed1991

Results and complications of angioplasty in aortoiliac disease.

Percutaneous transluminal angioplasty was used to treat 340 aortoiliac lesions in 200 patients who were followed for as long as 90 months (mean, 28.7 months; median, 23 months). The initial success rate was 94.7% for lesions and 93.0% for patients. The indications for percutaneous transluminal angioplasty included claudication in 117 patients (58.5%), rest pain or ischemic night pain in 47 (23.5%), limb salvage in 33 (16.5%), and aiding in wound healing in three (1.5%). In the series, 70% of the patients had two or more cardiovascular risk factors. Angioplasty was initially unsuccessful in 14 patients, and 10 patients were lost to follow-up. Follow-up was obtained in 176 patients. The long-term results were analyzed using the life table method to determine cumulative patency. Fourteen patients were considered failures because of recurrent disease or symptoms. The projected 7.5-year cumulative patency rate was 85%. When the response to redilatation was considered, the projected 7.5-year cumulative patency rate was 92%. The results indicate that percutaneous transluminal angioplasty can successfully correct aortoiliac lesions and provide a long-term benefit for as long as 7.5 years.

Angioplasty, Balloon↗
PubMed1991

First single lung transplant in Virginia.

Lung transplantation is now established as a clinical reality for patients with irreversible, lethal pulmonary conditions. We report the first successful application of this treatment modality in Virginia.

Humans↗
PubMed1991

A safe approach to the treatment of iliac artery aneurysms. Aortobifemoral bypass grafting with exclusion of the aneurysm.

Aneurysms of the iliac arterial system are often difficult to approach surgically. Aortobifemoral (ABF) bypass grafting with exclusion of the aneurysms can be used as an alternative to the usually recommended approach of endoaneurysmorrhaphy. Fourteen patients with iliac artery aneurysms treated by ABF are compared to 16 patients treated by direct repair to compare the incidence of complications related to decreased pelvic blood flow or to the presence of the excluded iliac artery aneurysm. There were no differences between the two groups. Therefore, it is concluded that ABF is a reasonable alternative in the treatment of iliac artery aneurysms.

Aged↗