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Biomedical subjects

D E Cameron

Publications and source records attributed to D E Cameron.

At least 19 recordsLinked to original sources
PubMed1995

Neutrophil modulation results in improved pulmonary function after 12 and 24 hours of preservation.

Neutrophils are important mediators of reperfusion injury, and suppression of neutrophil function or numbers can reduce reperfusion injury and improve long-term organ preservation in transplantation. NPC 15669, a leumedin, is a novel compound that prevents recruitment of neutrophils at inflammatory foci by inhibiting CD11b/CD18 adhesion molecule expression. NPC 15669 was used to inhibit neutrophil adhesion during reperfusion of isolated rabbit lungs after 12 and 24 hours of cold storage. Lungs (New Zealand White male rabbits, 2 to 3 kg) were flushed with 4 degrees C Euro-Collins (EC) solution, harvested en bloc, stored under various study conditions, and reperfused for 3 hours with fresh whole blood at 37 degrees C in an isolated perfusion system at constant flow and an inspired oxygen fraction of 1. Four groups (n = 6 each) were studied. Group I underwent immediate whole blood reperfusion. Group II were stored for 12 hours in 4 degrees C EC solution before reperfusion. Group III were stored for 12 hours in 4 degrees C EC solution and reperfused with whole blood containing NPC 15669 (10 mg/kg whole body weight). Group IV were stored for 24 hours in 4 degrees C EC solution and reperfused with whole blood containing NPC 15669 (10 mg/kg). Pulmonary artery and peak airway pressures were significantly lower and compliance higher in groups III and IV lungs after 3 hours of reperfusion (p < 0.05) compared with group I. Group I and III lungs had significantly less edema than group II (p < 0.05). The arterial partial pressure of oxygen was similar in all stored groups (II to IV).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Repair of coarctation of the aorta in neonates and infants: a thirty-year experience.

Between January 1962 and December 1991, 179 children less than 1 year of age underwent repair of coarctation of the aorta. Group I (1962 to 1971) consisted of 19 patients, group II (1972 to 1981) of 57 patients, group III (1982 to 1991) of 103 patients. Neonates (< 30 days old) made up 60% of group I, 57% of group II, and 70% of group III. The proportion of infants with associated complex cardiac abnormalities was 7% in group I, 25% in group II, and 39% in group III. Techniques of repair included resection with end-to-end anastomosis (n = 65), subclavian flap repair (n = 85), patch aortoplasty (n = 18), and other procedures (n = 11). The early mortality (< 30 days) was lowest in group III (group I, 21%; group II, 21%; and group III, 7%; p < 0.05), but the late mortality was similar in all groups (group I, 11%; group II, 13%; and group III, 15%). The overall actuarial survival was 57.7% +/- 0.15% at 27.1 years in group I, 65.7% +/- 0.07% at 19.7 years in group II, and 77.5% +/- 0.04% at 9.3 years in group III (p = not significant). Twenty-five restenoses requiring intervention occurred in 23 patients, for an overall restenosis rate of 16.4%. The incidence of restenosis was 23% for the patients who underwent end-to-end anastomosis, 11% for those who underwent subclavian flap repair (p < 0.1), and 27% for those who underwent patch aortoplasty (p < 0.01). Balloon angioplasty was successful in relieving 11 of the 12 restenoses in groups II and III.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Multiple↗
PubMed1995

AMPA glutamate receptor antagonism reduces neurologic injury after hypothermic circulatory arrest.

Pharmacologic inhibition of the N-methyl-D-aspartate (NMDA) glutamate receptor can reduce the neurologic injury associated with hypothermic circulatory arrest; however, other receptor subtypes, such as the alpha-amino-3-hydroxy-5-methylisoazole-4-propionic acid/kainate or AMPA/kainate subtype, may predominate in the adult brain. In this experiment, a selective AMPA antagonist, NBQX, was used in a canine survival model of hypothermic circulatory arrest. Twelve male dogs (20 to 25 kg) were placed on closed-chest cardiopulmonary bypass, subjected to 2 hours of hypothermic circulatory arrest at 18 degrees C, and rewarmed on cardiopulmonary bypass. All were mechanically ventilated and monitored for 20 hours before extubation and survived for 3 days. Six dogs received NBQX beginning 2 hours after arrest (3 mg/kg for 3 hours then 1.5 mg/kg for 2 hours). Control dogs received vehicle only. Neurologic recovery was assessed every 12 hours using a species-specific behavior scale that yielded a neurodeficit score ranging from 0 (normal) to 500 (brain dead). After sacrifice at 72 hours, brains were examined by receptor autoradiography and histologically for patterns of selective neuronal necrosis and scored blindly from 0 (normal) to 100 (severe injury). Dogs given NBQX had better neurologic function compared with controls (neurodeficit score, 58.6 +/- 15 versus 204 +/- 30; p < 0.004) and had less neuronal injury (18.2 +/- 3 versus 52.5 +/- 6; p < 0.004). Densitometric receptor autoradiography revealed preservation of neuronal NMDA receptor expression only in dogs given NBQX. These results suggest that antagonism of the non-NMDA glutamate receptor AMPA may be neuroprotective in adults after hypothermic circulatory arrest.

Animals↗
PubMed1995

Cerebral blood flow during cardiopulmonary bypass: influence of temperature and pH management strategy.

Because disordered autoregulation of cerebral blood flow may underlie neurologic injury associated with cardiopulmonary bypass (CPB), we studied the effects of normothermic (37 degrees C) and hypothermic (18 degrees C) CPB on cerebral vascular reactivity in 6 to 8-week-old piglets. Hypothermic CPB animals were subdivided into alpha-stat and pH-stat groups (n = 6 animals each group) according to acid-base management protocol. Cerebral blood flow (CBF), cerebral oxygen consumption (CMRO2), cerebral vascular resistance (CVR), and CBF response to hypercapnia were examined before, during, and 1 hour after CPB and used to calculate CVR per millimeter of mercury change in arterial partial pressure of CO2: (CVRnormocapnia - CVRhypercapnia)/(PaCO2 hypercapnia - PaCO2 normocapnia). Before CPB, CBF, CMRO2, and vascular reactivity to elevated CO2 were similar in the three groups; these parameters remained unchanged by normothermic CPB. However, during hypothermic CPB, CBF and CMRO2 decreased in both alpha-stat and pH-stat groups; in the alpha-stat group, CBF decreased from 27 +/- 5 mL.min-1.100 g-1 (normothermic CPB) to 5 +/- 1 mL.min-1.100 g-1 (hypothermic CPB) (p < 0.05) and CMRO2 decreased from 1.8 +/- 0.21 to 0.24 +/- 0.04 mL.min-1.100 g-1 (p < 0.05), whereas in the pH-stat group CBF decreased from 28 +/- 2 to 9 +/- 1 mL.min-1. 100 g-1 (p < 0.05) and CMRO2 decreased from 1.63 +/- 0.07 to 0.31 +/- 0.09 mL.min-1.100 g-1 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Aortic root replacement. Risk factor analysis of a seventeen-year experience with 270 patients.

Between September 1976 and September 1993, 270 patients underwent aortic root replacement at our institution. Two hundred fifty-two patients underwent a Bentall composite graft repair and 18 patients received a cryopreserved homograft aortic root. One hundred eighty-seven patients had a Marfan aneurysm of the ascending aorta (41 with dissection) and 53 patients had an aneurysm resulting from nonspecific medial degeneration (17 with dissection). These 240 patients were considered to have annuloaortic ectasia. Thirty patients were operated on for miscellaneous lesions of the aortic root. Thirty-day mortality for the overall series of 270 patients was 4.8% (13/270). There was no 30-day mortality among 182 patients undergoing elective root replacement for annuloaortic ectasia without dissection. Thirty-six of the 270 patients having root replacement also had mitral valve operations. There was no hospital mortality for aortic root replacement in these 36 patients, but there were seven late deaths. Twenty-two patients received a cryopreserved homograft aortic root; 18 of these were primary root replacements and four were repeat root replacements for late endocarditis. One early death and two late deaths occurred in this group. Actuarial survival for the overall group of 270 patients was 73% at 10 years. In a multivariate analysis, only poor New Year Heart Association class (III and IV), non-Marfan status, preoperative dissection, and male gender emerged as significant predictors of early or late death. Endocarditis was the most common late complication (14 of 256 hospital survivors) and was optimally treated by root replacement with a cryopreserved aortic homograft. Late problems with the part of the aorta not operated on occur with moderate frequency; careful follow-up of the distal aorta is critical to long-term survival.

Actuarial Analysis↗
PubMed1995

Quality of life in octogenarians after open heart surgery.

OBJECTIVES: To determine the quality of life in octogenarians after open heart surgery. BACKGROUND: Despite an increasing number of cardiac operations on octogenarians, the outcome as measured by functional status, independence of living, and psychological parameters of quality of life remain unproved. METHODS: Two groups of octogenarians (group 1, undergoing operation in 1986; group 2 in 1991) were reviewed retrospectively to determine operative mortality and functional results. RESULTS: Group 1 (n = 15, mean age of 83.2 years) and group 2 (n = 53, mean age 83.0 years) were studied. Operations included isolated coronary artery bypass grafting (group 1, 10; group 2, 29) and valve replacements +/- coronary artery bypass grafting +/- other procedures (group 1: 5; group 2, 24). Group 1 had 9% hospital mortality and 53% actuarial survival after a mean follow-up of 6.3 years. Group 2 had 17% hospital mortality and 72% actuarial survival after a mean follow-up of 1.5 years. At follow-up, significant improvements were observed in New York Heart Association (NYHA) angina class, congestive cardiac failure class, number of cardiovascular symptoms, and indices for satisfaction with overall life and general affect in both groups. Further, group 2 also showed significant improvements in independence of living, ease of life, and Karnofsky dependency category, but these improvements were less evident in group 1 after a longer period of follow-up. At follow-up, 75% of group 1 and 84% of group 2 octogenarians would definitely have made the same decision to undergo open heart surgery in retrospect. CONCLUSION: This study demonstrates improved quality of life after open heart surgery in octogenarians.

Activities of Daily Living↗
PubMed1994

Complement and neutrophil activation during cardiopulmonary bypass: a study in the complement-deficient dog.

Cardiopulmonary bypass (CPB) is known to cause complement and neutrophil activation, but the relative importance and interaction of these components in CPB-induced inflammation is unknown. In this study, a strain of dogs genetically deficient in the third component of complement (C3) was used to determine the contribution of C3 to neutrophil activation and pulmonary injury after CPB. Eleven dogs (5 C3-deficient and 6 controls) underwent 150 minutes of hypothermic CPB (28 degrees C) followed by 2 hours of observation. Before CPB, C3 levels were normal in controls and less than 1% of normal in C3-deficient dogs. In control dogs, functional activity of C3 decreased to 53.2% of baseline after 1 hour of CPB and there was immunohistochemical evidence of C3 deposition in lung after CPB; C3-deficient dogs had no C3 deposition in lung. Although similar degrees of neutropenia occurred during CPB in the two groups, expression of neutrophil adhesion molecule subunit CD18 was significantly lower in C3-deficient dogs than controls after 1 hour of CPB (45.9 +/- 3.7 versus 82.9 +/- 10.0 mean fluorescence units; p < 0.02). Postbypass lung tissue myeloperoxidase content was also less in C3-deficient dogs (43.8 +/- 4.6 versus 71.1 +/- 8.6 mumol x 10 mg-1 x min-1; p < 0.03). Cardiopulmonary bypass-associated lung injury (assessed by alveolar-arterial oxygen gradient, pulmonary vascular resistance, percent lung water, and light and electron microscopic appearance) was similar between groups. These results demonstrate that (1) C3 is deposited on pulmonary vascular endothelium during CPB and (2) C3 mediates increased expression of neutrophil CD18 and neutrophil sequestration in lung after CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Composite graft repair of Marfan aneurysm of the ascending aorta: results in 150 patients.

One hundred fifty consecutive Marfan patients undergoing composite graft repair of an ascending aorta aneurysm are reported. Twenty-six of the 150 patients had a preoperative dissection of the ascending aorta. There were no early deaths among 138 patients undergoing elective composite graft repair. There was one early death among 12 patients undergoing urgent operation; this patient arrived at the hospital with a rupturing aneurysm. Twenty-four of the 150 patients had mitral procedures; there were no early deaths in this group. There have been 14 late deaths among the 149 hospital survivors (9%). Actuarial survival of 150 patients at 1, 5, 10, and 14 years was 93%, 92%, 81%, and 73% respectively. Risk factors for early or late death were identified by multivariate analysis and only New York Heart Association class (III or IV) and male gender emerged as significant independent predictors of mortality. Late complications directly related to the composite graft have been gratifyingly low; only 2 patients had coronary dehiscence and 3 had thromboembolic events. Endocarditis emerged as an important late complication in 8 patients (5%). Two patients were successfully treated with antibiotics, 3 died before widespread availability of cryopreserved homografts, and 3 patients treated with antibiotics and homograft root replacement have had no evidence of recurrent infection. Seven patients with dissection in this series had aortic diameters of 6.5 cm or less. This experience supports the concept that composite graft repair in Marfan patients is mandated when the aneurysm reaches 5.5 to 6 cm, even in the asymptomatic patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Two decades of coronary artery bypass graft surgery in young adults.

Between January 1970 and December 1991, 201 patients < or = 40 years of age underwent coronary artery bypass graft surgery (CABG). Group 1 (1970 to 1980, n = 119) and group 2 (1981 to 1991, n = 82) corresponded to the eras before and after the onset of percutaneous transluminal coronary angioplasty (PTCA), respectively, and were analyzed for trends in patient profile, treatment, and risk factors for coronary artery disease (CAD): smoking, hypertension, hypercholesterolemia, diabetes, and family history. Mean age at operation was similar in the groups (1, 37 +/- 3.4 years; 2, 36 +/- 3.1 years). Women made up 18% of group 1 and 27% of group 2 (P = .048). Risk factor profile differed in the two groups: group 1 had more smokers (80%) than group 2 (68%) (P = .085), fewer patients with hypercholesterolemia (1, 37%; 2, 52%; P = .065), and significantly fewer diabetics (1, 10%; 2, 25%; P < .043). Mean preoperative New York Heart Association (NYHA) class was 3.2 in group 1 and 3.0 in group 2. The distributions of single-, double-, and triple-vessel CAD were similar in the groups. Preoperative myocardial infarction occurred in 55% of group 1 versus 61% in group 2 (P = NS). No group 1 patient received PTCA before CABG, but PTCA was performed in 15 group 2 patients. Left internal mammary artery grafts were used in 4% of group 1 and 57% of group 2 patients. CABG operative mortality was 7.0% in group 1 and 1.2% in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Inhibition of platelet adhesion during cardiopulmonary bypass reduces postoperative bleeding.

BACKGROUND: Thrombocytopenia and impaired platelet function after cardiopulmonary bypass (CPB) contribute to postoperative bleeding and may increase blood transfusion requirements. We tested the hypothesis that reversible inhibition of glycoprotein IIb/IIIa integrin-mediated platelet adhesion would reduce postoperative bleeding after CPB. METHODS AND RESULTS: Twelve mongrel dogs (21 to 24 kg) underwent 2.5 hours of hypothermic CPB followed by 6 hours of observation. The study group (n = 6) received a 90-micrograms/kg IV bolus of the glycoprotein IIb/IIIa inhibitor Integrelin, followed by continuous infusion (2 micrograms/kg per minute) during CPB; the control group (n = 6) received only drug vehicle. Platelet number and aggregometry, PaO2, and chest tube output were assessed serially. Lung wet weight, histology, and myeloperoxidase activity were also measured. At 120 minutes after CPB, the control group had significantly lower platelet counts (expressed as percent of pre-CPB values) when compared with the Integrelin group (control, 35.2 +/- 4.6%; Integrelin, 68.2 +/- 4.9%; mean +/- SEM; P < .05). Three hundred sixty minutes after CPB, platelet function (expressed as percent of pre-CPB aggregation induced by 10 mumol/L ADP) was better preserved in the Integrelin group (Integrelin, 20.8 +/- 3.0%; control, 43.9 +/- 10.4%; P < .05). The Integrelin group also had less total postoperative blood loss (control, 447 +/- 97 mL; Integrelin, 248 +/- 30 mL; P < .05). PaO2, lung wet weight, histology, and myeloperoxidase activity did not differ significantly between groups. CONCLUSIONS: This study demonstrates that inhibition of platelet adhesion during CPB results in (1) less platelet consumption, (2) better preservation of platelet function, and (3) less postoperative bleeding. Reversible platelet inhibition may have clinical utility in minimizing postoperative bleeding and reducing blood transfusions.

Animals↗
PubMed1993

EEG and prognosis of neurologic recovery of dogs under profound hypothermic circulatory arrest.

Deep hypothermia (18-20 degrees C) (DH) during prolonged circulatory arrest and cardiopulmonary bypass is used to repair complex intracardiac lesions and vascular neurosurgical lesions. DH diminishes the risk of ischemic damage and multiorgan failure after circulatory arrest. Profound hypothermia (PH) to 6-7 degrees C has recently been reported to improve the neurological outcome of dogs after 2 h of circulatory arrest. There are no reports of the possible utility of EEG activity to predict the neurological outcome. As a part of a controlled study of cardiopulmonary bypass and 2 h of circulatory arrest we compared EEG recovery to the neurological outcome in 2 groups of dogs: 4 under DH and 4 under PH. All of the dogs under PH had a good outcome: mean neurodeficit score was 6.25/500 in PH and 139.25/500 in DH dogs (P < 0.03); mean histopathological score was 19.25/100 for DH and 47.75/100 in PH dogs (P < 0.03). EEG activity 2 h after reperfusion and starting of rewarming correlated with eventual neurological outcome. EEG variables associated with good outcome were: main final frequency and degree of rhythmicity of the activity. We conclude that PH exerted a protective effect for animals undergoing 2 h of circulatory arrest. EEG was a useful tool for predicting neurological outcome under the studied conditions.

Animals↗
PubMed1992

Surgical treatment of postinfarction ventricular septal defect with aortic stenosis.

A 69-year-old man with an acute postinfarction ventricular septal defect was also found to have aortic stenosis. Successful management required closure of the postinfarction ventricular septal defect and replacement of the stenotic aortic valve. The contribution of aortic stenosis to the cause of the infarction and the postinfarction ventricular septal defect, as well as the implications for surgical management, are discussed.

Aged↗
PubMed1992

Hypothermic circulatory arrest as a surgical adjunct: a 5-year experience with 60 adult patients.

As a surgical adjunct, the technique of hypothermic circulatory arrest (HCA) is well established in pediatric cardiac surgery but is used less frequently in adults. This study was undertaken to review the application, utility, and safety of HCA in adult surgery at a single institution. Between January 1985 and October 1990, 60 adult patients (greater than 18 years old) underwent surgical procedures that included HCA. There were 30 men and 30 women; mean patient age was 56.4 years (range, 20 to 81 years). Operative procedures were thoracic aortic aneurysm repair (35 patients, 58%), resection of intraabdominal malignancy (15 patients, 25%), coronary artery bypass (4 patients, 7%), and other miscellaneous procedures (6 patients, 10%). Eighty-two percent of the procedures were elective, whereas 18% were emergencies. Mean circulatory arrest time was 28.5 minutes (range, 2 to 64 minutes). Operative mortality was 15%; by multivariate analysis, risk factors for death included prolonged cardiopulmonary bypass time (p less than 0.05), higher post-HCA rectal temperature (p less than 0.05), and intraoperative hypotension (p less than 0.001). Patient age, sex, emergency status, duration of HCA, and perfusion variables on cardiopulmonary bypass did not predict operative mortality. The incidence of perioperative neurologic injury was 15%. The only risk factor for neurologic injury was intraoperative hypotension (p less than 0.05). One- and 3-year actuarial survival for patients undergoing operation on the heart or great vessels was 75.9% and 70%, respectively, whereas patients with intraabdominal malignancy had 75% and 23.4% 1- and 3-year survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Pulmonary embolism in the cardiac surgical patient.

Pulmonary embolism (PE) is thought to occur infrequently after cardiac operations, possibly because systemic heparinization during cardiopulmonary bypass prevents deep vein thrombosis. This retrospective study was undertaken to determine the actual incidence of PE after cardiac operations and to identify risk factors. Between January 1, 1985, and December 31, 1989, 5,694 adult patients (greater than 18 years old) had open heart operations at the Johns Hopkins Hospital. Thirty-two patients (20 men and 12 women) had PE within 60 days of operation, an overall PE incidence of 0.56%. The diagnosis of PE was established by ventilation/perfusion scan, pulmonary angiogram, or autopsy. Mortality among patients with PE was 34%. Using a case-control method, preoperative and postoperative risk factors for PE were identified by multivariate and multiple logistic regression analyses. Preoperative risk factors included bed rest (p less than 0.003), prolonged hospitalization before operation (p less than 0.004), and cardiac catheterization performed through the groin within 15 days before operation (p less than 0.01). Post-operative risk factors were congestive heart failure (p less than 0.008), prolonged bed rest (p less than 0.05), and deep vein thrombosis (p less than 0.03). This study demonstrates that PE is an unusual complication after cardiac operations, has a high mortality rate, and is often related to perioperative immobility and recent groin catheterization. These results also suggest that minimizing preoperative hospital stay may be important in PE prophylaxis.

Bed Rest↗
PubMed1992

Demonstration of cytomegalovirus nucleic acids in the coronary arteries of transplanted hearts.

Cytomegalovirus (CMV) infection has been associated with the development of accelerated arteriosclerosis in heart transplant recipients. This association prompted the authors to examine, using in situ hybridization techniques, the coronary arteries of 19 patients who had received heart transplants for the presence of CMV nucleic acids. Two probes were employed on formalin-fixed paraffin-embedded tissues. The first was an S35-labeled nick translated probe derived from CMV DNA. CMV nucleic acids were identified in the arterial intima of 5 (45%) of 11 transplanted hearts examined with this probe. Hybridization to cells morphologically consistent with endothelial cells, lymphocytes, and smooth muscle cells was identified. Hybridization was not detected in any of the hearts when a control probe, a vector without CMV DNA, was employed. The second probe that was used was a tritium-labeled strand-specific ribo-probe derived from the immediate early (IE1) gene of CMV. Using this second probe, hybridization was detected in the coronary arteries of three of five hearts that were positive with the DNA probe, in one of the hearts that was negative with the DNA probe, and in three (38%) of eight additional transplanted hearts. The pattern of hybridization was the same as that seen with the DNA probe, and no hybridization was detected when a control sense probe for the IE1 gene of CMV was employed. These results suggest that CMV nucleic acids are present in the coronary arteries of heart transplant recipients.

Adolescent↗
PubMed1992

Cardiopulmonary bypass and the blood-brain barrier. An experimental study.

The diffuse inflammation produced by cardiopulmonary bypass might disrupt the blood-brain barrier and lead to the transient neurologic dysfunction occasionally seen after cardiac operations. To evaluate this possibility, blood-brain barrier integrity was measured by carbon 14-aminoisobutyric acid tracer technique after 2 hours of cardiopulmonary bypass in piglets. Six animals were cooled to 28 degrees C on cardiopulmonary bypass and then rewarmed to 38 degrees C before carbon 14-aminosisobutyric acid was injected intraarterially. A control group of six animals underwent median sternotomy and heparinization but were not placed on cardiopulmonary bypass. Blood-to-brain transfer coefficients for carbon 14-aminosisobutyric acid were calculated for multiple brain regions; higher coefficients reflect greater flux of carbon 14-aminosisobutyric acid and suggest loss of blood-brain barrier integrity. The brain regions examined and their transfer coefficients (cardiopulmonary bypass versus control mean +/- standard error of the mean ml/gm/min) were middle cerebral artery territory cortex (0.0032 +/- 0.0002 versus 0.0030 +/- 0.0002; p = 0.42), diencephalon (0.0031 +/- 0.0003 versus 0.0029 +/- 0.0002; p = 0.50), midbrain (0.0028 +/- 0.0002 versus 0.0027 +/- 0.0002; p = 0.86), cerebellum (0.0036 +/- 0.0003 versus 0.0029 +/- 0.0002; p = 0.22), and spinal cord (0.0035 +/- 0.0003 versus 0.0041 +/- 0.0008; p = 0.48). There were no significant differences in transfer coefficients between animals placed on cardiopulmonary bypass and control animals in any brain region examined. The pituitary gland lacks a blood-brain barrier and had a correspondingly high coefficient in control animals and those undergoing cardiopulmonary bypass (0.077 +/- 0.012 versus 0.048 +/- 0.008; p = 0.07). Two hours of moderately hypothermic cardiopulmonary bypass does not disrupt the blood-brain barrier.

Aminoisobutyric Acids↗
PubMed1992

Absorbable suture improves growth of venous anastomoses.

Growth of vascular anastomoses is desirable in pediatric vascular surgery, especially in pediatric organ transplantation. Although absorbable suture has been shown to be superior to nonabsorbable suture in permitting growth of arterial anastomoses, the optimal suture material for venous anastomoses has not been established. To examine this in a porcine model, we performed bilateral primary end-to-end anastomoses of transected external jugular veins in 10, 4-week-old piglets. In each piglet one anastomosis was constructed with continuous absorbable 8-0 polyglyconate suture, whereas the contralateral anastomosis was constructed with continuous nonabsorbable 8-0 polypropylene suture. After 6 months the veins were excised, pressure fixed at 15 mm Hg for 2 hours, and examined grossly and histologically. Vein diameter was measured by contrast radiography at the anastomosis and 1 cm proximal and distal to the anastomosis. Vein cross-sectional area 1 cm from the anastomosis was similar in the two groups: polyglyconate 95.7 +/- 12.3 mm2 versus polypropylene 95.3 +/- 9.7 mm2. However, polyglyconate anastomoses had greater cross-sectional area (polyglyconate 72.8 +/- 7.9 mm2 vs polypropylene 51.8 +/- 6.0 mm2; p < 0.05). In addition, at 6 months polyglyconate anastomoses had a greater percentage of growth (polyglyconate 207% vs polypropylene 118%; p < 0.05) compared with native vein cross-sectional area (23.7 +/- 0.39 mm2) from control pigs at 4 weeks of age. On histologic examination, polyglyconate had dissolved entirely in six cases and was present but in varying degrees of dissolution in the other four; in contrast, polypropylene was identifiable at all anastomoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗