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Biomedical subjects

C G Tribble

Publications and source records attributed to C G Tribble.

At least 109 records · Page 6Linked to original sources
PubMed1993

Impairment of vascular endothelial function by high-potassium storage solutions.

High-potassium cold storage solutions are currently used to preserve myocardial function during heart transplantation. However, the effects of high potassium concentration on vascular endothelial function are not well known. We therefore tested vascular rings for endothelial-dependent and endothelial-independent relaxation during storage in normokalemic, normothermic buffers and then in buffers supplemented with 10 to 110 mmol/L KCl. Maximal endothelial-dependent relaxation was significantly reduced at all high potassium concentrations. Endothelial-independent relaxation was impaired only with 80 and 110 mmol/L KCl buffers. Both endothelial-dependent relaxation and endothelial-independent relaxation returned to normal values after washout of excess potassium. Similarly, endothelial-dependent relaxation and endothelial-independent relaxation were assessed in rings after 24 hours of hypothermic storage in normokalemic Krebs buffer, and in buffers containing 20 and 110 mmol/L KCl. Maximal endothelial-dependent relaxation was significantly reduced after preservation in the high-potassium solutions, whereas endothelial-independent relaxation was not impaired. We conclude that there is significant impairment of endothelial function after cold storage in a high-potassium buffer. Inadequate washout of potassium during normothermic conditions may lead to further functional impairment of vascular responsiveness. A low-potassium storage medium is recommended for improved vascular protection.

Animals↗
PubMed1993

Thoracoscopic diagnosis and treatment of mediastinal masses.

Evaluation of mediastinal masses often involves an array of imaging procedures and percutaneous biopsy techniques. Despite this, surgical intervention with an open biopsy is often required, especially to diagnose mediastinal malignancies. We report 22 patients with mediastinal masses who were managed with thoracoscopic biopsy, as opposed to open biopsy. All of these patients either had unsuccessful fine-needle aspiration or were unacceptable candidates for percutaneous aspiration. The patients ranged in age from 11 months to 67 years with a mean age of 17.2 +/- 3.6 years. Thoracoscopy provided an accurate tissue diagnosis in 19 of the 22 patients (86%) without need for an open diagnostic procedure. In 1 patient, histoplasmosis was suspected from the thoracoscopic biopsy, but open thoracotomy was needed for confirmation. Of the 19 patients with a positive tissue diagnosis, 3 patients had bronchogenic cysts that were completely resected by thoracoscopy. The mean duration of chest tube drainage was 2.3 +/- 0.2 days, and there were no complications or procedure-related deaths. The average length of hospitalization was 6.0 +/- 0.8 days. We believe that thoracoscopy is a safe, rapid, and effective modality for the diagnosis of mediastinal masses. Accurate tissue diagnoses are obtained in most patients without the need for additional procedures. In addition, we have demonstrated that complete excision of certain benign lesions during thoracoscopy is possible.

Adolescent↗
PubMed1993

Successful transplantation of marginally acceptable thoracic organs.

OBJECTIVE: This study evaluates the efficacy of personally inspecting marginal thoracic organ donors to expand the donor pool. SUMMARY BACKGROUND DATA: The present donor criteria for heart and lung transplantation are very strict and result in exclusion of many potential thoracic organ donors. Due to a limited donor pool, 20-30% of patients die waiting for transplantation. METHODS: The authors have performed a prospective study of personally inspecting marginal donor organs that previously would have been rejected by standard donor criteria. RESULTS: Fourteen marginal hearts and eleven marginal lungs were inspected. All 14 marginal hearts and 10 of the marginal lungs were transplanted. All cardiac transplant patients did well. The mean ejection fraction of the donor hearts preoperatively was 39 +/- 11% (range 15-50%). Postoperatively, the ejection fraction of the donor hearts improved significantly to 55 +/- 3% (p < 0.002). Nine of the ten lung transplant patients did well and were operative survivors. Our donor pool expanded by 36% over the study period. CONCLUSIONS: The present donor criteria for heart and lung transplantation are too strict. Personal inspection of marginal thoracic donor organs will help to maximize donor utilization.

Heart↗
PubMed1993

Thoracoscopic surgery for diseases of the lung and pleura. Effectiveness, changing indications, and limitations.

OBJECTIVE: This study compared the results of video-assisted thoracic surgery (VATS) with thoracoscopic surgery (TS) for diseases of the lung and pleura. SUMMARY BACKGROUND DATA: No studies exist that compare the capabilities of VATS with advanced video systems and instrumentation to that of TS which has been done for 80 years. METHODS: A retrospective study was done comparing the effectiveness, indications, complications, and limitations of TS and VATS done for four categories of pleural disease: 1) pleural fluid problems, 2) diffuse lung disease, 3) lung masses, and 4) pneumothorax. The TS period was 1981-1990. The VATS period was 1991-1992. RESULTS: Eighty-nine consecutive TS cases and 64 consecutive VATS cases were reviewed. TS for resolution of pleural fluid problem was successful in 29 of 34 patients (85%), and VATS was successful in 18 of 20 (90%). Diffuse lung disease was diagnosed by TS using a cup biopsy on end-stage patients in respiratory failure. Since 1991 the diagnosis has been made with VATS using stapled wedge excisions on ambulatory patients. Surgical mortality decreased from 33% (10 of 30) to 9% (1 of 11) and the postoperative stay from 16.6 +/- 2.4 days to 8.2 +/- 2.2 days. Lung masses were diagnosed entirely by incisional biopsies using TS. Diagnosis was made in 83% and postoperative stay was 5.3 +/- 1.0 day. VATS allowed excisional biopsies permitting diagnosis in 100% with a postoperative stay of 3.0 +/- 0.2 days (p = 0.05). However, 20% required conversion to thoracotomy to locate the subpleural mass. TS was performed for spontaneous pneumothorax in only 26% (5 of 19) of the total pneumothorax cases, whereas, VATS was used for spontaneous pneumothorax in 67% (12 of 18). CONCLUSION: VATS has continued the effectiveness of TS for treating pleural fluid problems, has resulted in earlier surgical diagnostic intervention in diffuse lung disease and earlier therapeutic intervention in primary pneumothorax states, and has markedly expanded the safety, efficacy and indications for lung mass biopsy.

Adolescent↗
PubMed1993

Balloon angioplasty above the aortic arch: immediate and long-term results.

OBJECTIVE: Angioplasty above the level of the aortic arch is becoming more common, and the indications for it are increasing. We report our experience with this procedure, including life-table analysis of the long-term results. MATERIALS AND METHODS: We dilated 32 lesions in 29 patients. Early in our series, patients were referred primarily because of arm claudication or vertebrobasilar insufficiency. Subsequently, the indications were expanded to include inflow to left internal mammary-coronary artery bypass grafts, inflow to axillobifemoral bypass grafts, and inflow to dialysis fistulas in the upper extremity. A femoral artery approach was used in 18 patients and an axillary approach was used in 11. Clinical follow-up included evaluation of symptoms and bilateral measurements of peripheral pulses and blood pressure. Follow-up angiograms were obtained in nine patients. RESULTS: Eighteen of the lesions dilated were located in the left subclavian artery, eight were in the right subclavian artery, four were in the axillary or proximal brachial artery, and two were in the innominate artery. Interestingly, three of eight right subclavian arteries treated had an anomalous origin from the arch of the aorta. Initial technical success was 100%. All 29 patients had long-term follow-up of 4-88 months (mean, 36 months). In one patient, stenosis recurred 8 months after angioplasty. This patient subsequently had redilatation. Life-table analysis projected a 7.5-year cumulative primary patency rate of 96.6%. No cerebrovascular complications or embolic events occurred. CONCLUSION: Angioplasty of the great vessels is safe and effective, and the long-term results are favorable when compared with results after surgery. As a result, the indications for this procedure should be broadened.

Adult↗
PubMed1993

Regional adenosine attenuates postischemic spinal cord injury.

PURPOSE: Operations on the thoracic and thoracoabdominal aorta are associated with postoperative paraplegia rates as high as 20% to 30%. Attempts to reduce this complication have focused on decreasing the energy needs of the spinal cord with protective agents such as hypothermia and barbiturates or on increasing blood flow with various shunts. This study explores the hypothesis that perfusion of the spinal cord with hypothermic solutions or with adenosine will prevent or ameliorate paraplegia. METHODS: New Zealand white rabbits underwent 40 minutes of infrarenal aortic isolation. The infrarenal aorta is the primary source of spinal cord blood supply in the New Zealand white rabbit. Control rabbits sustained aortic occlusion without any protective measures. The remaining animals were randomized into three groups that underwent aortic cross-clamping with various protective adjuncts. Group I received regional aortic hypothermia perfusion, group II received systemic adenosine, and group III received regional aortic perfusion with high-dose adenosine. RESULTS: Neurologic function was graded according to the Tarlov scale (0 = no movement, 1 = slight movement, 2 = sits with assistance, 3 = sits alone, 4 = weak hop, 5 = normal hop). After 96 hours animals were euthanized, and spinal cords were harvested for histologic examination. The nonparaplegic animals in group I had a mean Tarlov score of 1.5, whereas those in group III had a mean score of 3.4. Histologic studies on spinal cord tissue revealed no significant differences between the study groups. CONCLUSIONS: These data demonstrate that administration of regional adenosine attenuates ischemic injury associated with aortic occlusion in this experimental model.

Adenosine↗
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↗