Biomedical subjects

G Pettersson

Publications and source records attributed to G Pettersson.

At least 55 records · Page 3Linked to original sources

PubMed1998

Substrate specificity of cellobiose dehydrogenase from Phanerochaete chrysosporium.

Substrate structural mapping suggests that the catalytic site of cellobiose dehydrogenase from Phanerochaete chrysosporium forms a narrow cave with two hexose binding subsites. Kinetic data also show that beta-di or oligosaccharides are favored electron donors with respect to both KM and kcat. Surprisingly, thiocellobiose showed an even higher kcat than cellobiose, although the KM value was somewhat higher. The CDH was purified using an updated protocol.

Basidiomycota↗

PubMed1998

Analyses of coronary graft patency after aprotinin use: results from the International Multicenter Aprotinin Graft Patency Experience (IMAGE) trial.

OBJECTIVE: We examined the effects of aprotinin on graft patency, prevalence of myocardial infarction, and blood loss in patients undergoing primary coronary surgery with cardiopulmonary bypass. METHODS: Patients from 13 international sites were randomized to receive intraoperative aprotinin (n = 436) or placebo (n = 434). Graft angiography was obtained a mean of 10.8 days after the operation. Electrocardiograms, cardiac enzymes, and blood loss and replacement were evaluated. RESULTS: In 796 assessable patients, aprotinin reduced thoracic drainage volume by 43% (P < .0001) and requirement for red blood cell administration by 49% (P < .0001). Among 703 patients with assessable saphenous vein grafts, occlusions occurred in 15.4% of aprotinin-treated patients and 10.9% of patients receiving placebo (P = .03). After we had adjusted for risk factors associated with vein graft occlusion, the aprotinin versus placebo risk ratio decreased from 1.7 to 1.05 (90% confidence interval, 0.6 to 1.8). These factors included female gender, lack of prior aspirin therapy, small and poor distal vessel quality, and possibly use of aprotinin-treated blood as excised vein perfusate. At United States sites, patients had characteristics more favorable for graft patency, and occlusions occurred in 9.4% of the aprotinin group and 9.5% of the placebo group (P = .72). At Danish and Israeli sites, where patients had more adverse characteristics, occlusions occurred in 23.0% of aprotinin- and 12.4% of placebo-treated patients (P = .01). Aprotinin did not affect the occurrence of myocardial infarction (aprotinin: 2.9%; placebo: 3.8%) or mortality (aprotinin: 1.4%; placebo: 1.6%). CONCLUSIONS: In this study, the probability of early vein graft occlusion was increased by aprotinin, but this outcome was promoted by multiple risk factors for graft occlusion.

Adult↗

PubMed1998

Treatment of aortic valve endocarditis with the Ross operation.

OBJECTIVE: Standard treatment of patients with infective endocarditis is radical debridement and valve replacement, in cases with advanced pathology the treatment is usually root replacement with either a composite graft or a homograft. Enthusiasm for the use of the Ross operation in non-infective aortic valve disease is increasing, but use of the pulmonary autograft in the treatment of aortic valve endocarditis has been limited. The objective of this prospective study is to present the technique and results of our experience with aortic valve endocarditis treated with the Ross operation. MATERIALS AND METHODS: Since 1992 we have treated 35 patients (median age 41 years, range 6-71 years) having aortic valve endocarditis with a Ross operation. Twenty-four patients had advanced disease defined as pathology due to endocarditis extending beyond the valve cusps (13 patients) or prosthetic valve endocarditis (11 patients). Twenty-two patients had active disease at the time of surgery, and 12 had undergone one to four previous heart operations. RESULTS: There were two operative deaths (5.8%), both related to severe disease with very advanced pathology and heart failure. Intraoperative echocardiography demonstrated no or trivial autograft insufficiency in all patients. There have been no late deaths. There has been one (probable) recurrent right-sided endocarditis in a drug addict during a follow-up period of 3-56 months. One patient has been reoperated on for homograft stenosis. CONCLUSIONS: We are enthusiastic about the use of the Ross operation in aortic valve endocarditis and in younger patients with advanced pathology, it is our preferred treatment modality. Following removal of the autograft, unparalleled exposure of the left ventricular outflow tract is obtained. Even in patients with very advanced pathology the left ventricular outflow tract is usually intact, allowing autograft implantation in the standard fashion. For selected patients with simple endocarditis, the Ross operation is an attractive option on its usual merits.

Adolescent↗

PubMed1998

Does bronchial artery revascularization influence results concerning bronchiolitis obliterans syndrome and/or obliterative bronchiolitis after lung transplantation?

OBJECTIVE: To study the frequency of histological obliterative bronchiolitis and clinical bronchiolitis obliterans syndrome after en bloc double lung transplantation with bronchial artery revascularization and bilateral lung transplantation without bronchial artery revascularization. METHODS: Primary en bloc double lung transplantation with bronchial artery revascularization using the internal mammary artery as conduit was performed in 62 patients. The frequencies of obliterative bronchiolitis and bronchiolitis obliterans syndrome have been established from transbronchial biopsies and lung function measurements. Results have been analyzed in relation to the arteriographic success of bronchial artery revascularization and have been compared to results from Stanford University, obtained through personal communications. RESULTS: Survival after 1, 2, 3, 4 and 5 years was 85, 81, 69, 69, and 69%, respectively. Fifteen patients developed bronchiolitis obliterans syndrome while seven developed obliterative bronchiolitis. Survival was superior for patients with bronchial artery revascularization classified as complete or incomplete bilateral versus incomplete hemilateral, incomplete poor or failed (P = 0.016, log-rank test). For patients surviving > or = 3 months post-transplant, the post-operative baseline FEV1 was lower for patients who later developed bronchiolitis obliterans syndrome compared to patients who did not (P = 0.007). The development of bronchiolitis obliterans syndrome and obliterative bronchiolitis were both correlated to observation time post-transplant but not to the number of rejections or infections when corrected for observation time. CONCLUSIONS: In a subgroup of lung transplant patients, a process in the transplanted lungs, eventually leading to bronchiolitis obliterans syndrome diagnosis, seems to start in the donor during the transplantation and/or in the early post-operative cause. A comparison with results after bilateral lung transplantation without bronchial artery revascularization suggests that good direct bronchial artery revascularization may postpone the onset of bronchiolitis obliterans syndrome and obliterative bronchiolitis. The positive trend motivates further use of direct bronchial artery revascularization in lung transplantation.

Adolescent↗

PubMed1997

Mechanism of NADH transfer between alcohol dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase.

Steady-state and transient-state kinetic experiments have been performed to test the proposal that there is a direct (channelled) transfer of NADH from glyceraldehyde-3-phosphate dehydrogenase to alcohol dehydrogenase. The results lend no support to this proposal, but can be best explained in terms of a free-diffusion mechanism for NADH transfer between the two enzymes.

Alcohol Dehydrogenase↗

PubMed1997

Studies of cellulose binding by cellobiose dehydrogenase and a comparison with cellobiohydrolase 1.

The binding isotherm to cellulose of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium has been compared with that of cellobiohydrolase 1 (CBH 1) from Trichoderma reesei. CDH binds more strongly but more sparsely to cellulose than does CBH 1. In a classical Scatchard analysis, a better fit to a one-site binding model was obtained for CDH than for CBH 1. The binding of both enzymes decreased in the presence of ethylene glycol, increased in the presence of ammonium sulphate and was unaffected by sodium chloride. Attempts to localize the cellulose-binding site on CDH have also been made by exposing enzymically digested CDH to cellulose and isolating the cellulose-bound peptides. The results suggest that the cellulose-binding site is located internally in the amino acid sequence of CDH.

Amino Acid Sequence↗

PubMed1997

[Clinical results after en block double lung transplantation with direct bronchial revascularization. The first three and a half years' experience in Denmark].

En-bloc double lung transplantation with tracheal anastomosis and direct revascularization of the bronchial arteries to the left internal mammary artery has been carried out in Denmark since June 1992. Forty-seven patients (32 with alfa-1 antitrypsin deficiency, 11 with chronic obstructive pulmonary disease, two with cystic fibrosis and two with primary pulmonary hypertension), 25 men and 22 women, average age 39 years (17-64 years), have received their first double-lung transplant with bronchial artery revascularization. Arteriography of the internal mammary artery and bronchial arteries was performed in 42 (89%) of the patients from 1-150 days after the operation. Successful bronchial artery revascularization was demonstrated arteriographically in 40 patients, in two patients the arteriography failed to show bronchial artery revascularization. Arteriography was not performed in five patients due to early complications and death. Bronchoscopy showed rapid, uncomplicated airway healing in 42 patients. Mucosal necrosis under the tracheal anastomosis was found in three patients, and severe obstructive endobronchial growth of the fungus Aspergillus fumigatus was diagnosed in the last two patients. The one- and two-year survival is 83% (Kaplan-Meier). Eleven patients are dead, five due to pulmonary causes and six due to extra-pulmonary causes. Pulmonary function became normal in nearly all surviving patients between three to six months after the transplantation. In conclusion, en-bloc double-lung transplantation with bronchial artery vascularization has shown good short-term results, and the one- and two-year survival gives hope that a successful bronchial artery revascularization will improve the long-term survival following lung transplantation.

Adolescent↗

PubMed1997

[Coronary bypass surgery at the Rigshospitalet 1993-1995. Results after 1.000 consecutive operations].

During 1993-95 1000 consecutive patients were admitted for coronary bypass surgery. The total 30-day mortality of 1.9% was 0.9% for elective cases, 0.8% for reoperations and 0.2% for urgent cases. Perioperative myocardial infarction occurred in 44 patients of whom 25% had infarction at the start of the operation. Respiratory insufficiency occurred in 1.4% of the patients, 3.6% developed renal insufficiency and 1.8% had neurological defects postoperatively. Reoperation for bleeding occurred in 6%, and 0.2% developed sternal or mediastinal infection. This study demonstrates that the results of coronary bypass surgery at Rigshospitalet, Copenhagen are fully comparable to similar results in our neighbouring countries. The results can probably be further improved by more intensive treatment of perioperative ischaemia, especially in reoperations and urgent cases.

Adult↗

PubMed1997

One-stage repair of truncus arteriosus, CAVC, and TAPVC.

An infant with truncus arteriosus, complete atrioventricular canal, and total anomalous pulmonary venous connection successfully underwent one-stage complete repair. Residual mitral valve regurgitation required reoperation after 12 days. The patient is doing well at 6 months' follow-up. Echocardiography demonstrates no residual defects, competent atrioventricular valves, and normal pulmonary pressure. This case illustrates the potential for successful one-stage repair even of associated complex heart defects involving venous, intracardiac, and arterial pathways.

Abnormalities, Multiple↗

PubMed1997

Medium-term patency and anatomic changes after direct bronchial artery revascularization in lung and heart-lung transplantation with the internal thoracic artery conduit.

OBJECTIVE: Our purpose was to study the 2-year patency of direct bronchial artery revascularization in lung transplantation. We wanted to clarify whether the revascularized bronchial artery system is functional after 2 years, whether bronchial artery vascularity changes with time, and whether posttransplantation bronchial artery disease is arteriographically evident after 2 years. METHODS: Bronchial artery revascularization is performed by anastomosing the internal thoracic artery to as many bronchial artery orifices in the donor descending aorta as possible. Twenty-three patients surviving 2 years or more have had internal thoracic artery-bronchial arteriography performed 1 month and 2 years after transplantation. One-month and 2-year arteriograms have been compared. RESULTS: Two-year patency of the internal thoracic artery conduit was 100%. The appearance of the bronchial arteries was unchanged after 2 years in 11 patients. A unilateral or bilateral increase in vascularity was found in two and seven patients, respectively. In three patients new vessels, not visible on the first arteriogram, had appeared. In four patients one or more small vessels visible on the first arteriogram had disappeared on the second arteriogram. We have found no arteriographic signs of bronchial artery disease, such as stenosis of the bronchial arteries, and no arteriographic evidence of arteriosclerotic disease in the internal thoracic artery. CONCLUSION: The internal thoracic artery is an excellent conduit for bronchial artery revascularization, with a 2-year patency of 100% in 23 patients. Only minor changes in the bronchial arteriograms have been found.

Bronchial Arteries↗

PubMed1997

Early experience with the Norwood procedure.

The improved results of the Norwood procedure have recently stimulated its widespread adoption in many centres. Since 1993, 19 infants with hypoplastic left heart syndrome or similar conditions underwent a first-stage Norwood procedure. Circulatory arrest time was significantly reduced by using a modified repair of the aortic arch. The early mortality rate was 31.5% (n = 6). The addition of CO2 to the inspired gas mixture resulted in less early postoperative instability. Nine patients have subsequently undergone bidirectional cavopulmonary shunt and one fenestrated total cavopulmonary connection. Overall there have been five late deaths, two as result of failure of cavopulmonary operations. All the eight survivors are presently in good condition. One is awaiting bidirectional cavopulmonary shunt and the other seven total cavopulmonary connection. This early experience encourages the continued offering of the Norwood procedure to patients with hypoplastic left heart syndrome or its variants. Increasing experience with the perioperative care and a more careful evaluation before cavopulmonary operations may determine further improvement in the outcome.

Aorta, Thoracic↗

PubMed1997

Is the arterial switch operation still a challenge in small centers?

OBJECTIVE: In the last years, major changes as regards timing for operation, surgical technique, and perioperative care determined a great improvement in the arterial switch operation (ASO) allowing excellent mid-term results in a few leading centers. This stimulated the widespread adoption of ASO as procedure of choice for transposition of the great arteries (TGA), even in small institutions. We reviewed our early experience with ASO in an attempt to evaluate its safety in a small center. METHODS: Since April 1992, 39 consecutive patients underwent TGA repair by ASO in our department. There were 27 patients with simple TGA, 8 with TGA and VSD and 4 with Taussig-Bing heart and aortic coarctation. Median age and weight at operation were 7 days and 3.5 kg, respectively. Neonatal repair was performed in 34 patients. In accordance with the Planché coronary classification, type I was encountered in 21 patients, type II in 4 and type III in 14. Several modifications of the original technique were used, mainly regarding coronary relocation, pulmonary artery reconstruction and approaches for associated VSD closure and aortic arch repair. RESULTS: Early mortality was 2.6% (n = 1), the only operative death being related to unsatisfactory coronary relocation. Since modified ultrafiltration was adopted, mean ICU stay decreased from 5 +/- 4 days (n = 21) to 2 +/- 1 days (n = 17) (P < 0.05). Three patients required reoperation for residual ASD and/or VSD closure. There were no late deaths. After a mean follow-up of 26 +/- 15 months all survivors are thriving and are currently asymptomatic. CONCLUSIONS: Although this series is rather small, most of the major coronary anomalies and complex anatomic associations were encountered. This experience suggests that neonatal repair of TGA by ASO can be safely accomplished even in small centers. Modified ultrafiltration appears to improve the early outcome of neonates undergoing ASO.

Cause of Death↗

PubMed1997

Re-mediastinoscopy in the assessment of resectability of lung cancer.

OBJECTIVE: Thirty-one patients underwent re-mediastinoscopy in the diagnostic assessment of lung cancer. The reason for a repeat mediastinoscopy was either a negative result at the first operation in spite of CT indication of enlarged nodes or an incomplete first mediastinoscopy. METHODS: All patients underwent a conventional mediastinoscopy. RESULTS: In 22 patients with enlarged mediastinal lymph nodes at computed tomography, 10 had a positive lymph node histology at re-mediastinoscopy, while 12 were negative. In 9 patients with no enlarged mediastinal nodes at CT scan, but incomplete biopsies at the first mediastinoscopy, 1 patient had lymph node metastases. The median duration from the first to the second mediastinoscopy was 43 days. No major complications occurred. The staging of the patients was greatly affected by the re-mediastinoscopy. Of 31 patients judged as operable according to the initial mediastinoscopy only 60% were found to be operable following the second mediastinoscopy. CONCLUSION: This study has demonstrated the value of re-mediastinoscopy in assessment of resectability of lung cancer.

Adult↗

PubMed1997

Significance and management of early graft failure after coronary artery bypass grafting: feasibility and results of acute angiography and re-re-vascularization.

UNLABELLED: Perioperative ischaemia and infarction after CABG are associated with increased morbidity and mortality. OBJECTIVE: To study causes of perioperative ischaemia and infarction by acute re-angiography and to treat incomplete re-vascularization caused by graft failure or any other cause. METHODS: Between 1990 and 1995, 2003 patients underwent an isolated CABG operation. Myocardial ischaemia was suspected if one or more of the following criteria were present: New changes in the ST-segment in the ECG; a CKMB value greater than 80 U/L; new Q-waves in the ECG; recurrent episodes of, or sustained ventricular tachyarrhythmia; ventricular fibrillation; haemodynamic deterioration and left ventricular failure. Acute coronary angiography was performed in stable patients, while haemodynamically severely compromised patients were rushed to the operating room. RESULTS: A total of 71 (3.5%) patients of all CABGs with suspected graft failure were identified and included in the study. Patients were grouped according to whether they had an acute re-angiography (n = 59; group 1) or an immediate re-operation (n = 12; group 2) performed. In group 1, the acute re-angiography demonstrated graft failure/incomplete re-vascularization in 43 patients (73%). The angiographic findings were: Occluded vein graft(s) in 19 (32%); poor distal run-off to the grafted coronary artery in ten (17%); internal mammary artery stenosis in four (7%); internal mammary artery occlusion in three (5%); vein graft stenoses in three (5%); left mammary artery subclavian artery steal in two (3%); and the wrong coronary artery grafted in one (2%). Based on the angiography findings, 27 patients were re-operated and re-grafted. At the time of re-operation, 18 patients (67%) had evolving infarction documented by ECG or CKMB. Two patients (3%) experienced stroke in immediate relation to the re-angiography. The 30-day mortality was three (7%). In group 2, graft occlusions were found in 11 patients (92%). The 30-day mortality was six (50%). CONCLUSION: An acute re-angiography demonstrated graft failure or incomplete re-vascularization in the majority of patients with myocardial ischaemia early after CABG. Re-operation for re-re-vascularization was performed with low risk. Few patients with circulatory collapse could be saved by an immediate re-operation without preceding angiography.

Adult↗

PubMed1997

Treatment of massive haemoptysis with microcoil embolization after en bloc double-lung transplantation with bronchial artery revascularization.

Successful treatment of a severe haemoptysis with microcoil embolization in an en block double-lung transplanted patient is described. A 53 year old woman with advanced bronchiolitis obliterans syndrome experienced severe haemoptysis 26 months after an en bloc double-lung transplantation with direct bronchial artery revascularization using the left internal mammary artery. Bronchoscopy showed that the haemoptysis originated from the lingula. Only two months after the transplant, left internal mammary arteriograms revealed proliferation and enlargement of the bronchial arteries in the lingula. The early occurrence of the vascular malformation indicated a pre-existing bronchiectasis in the donor lung, possibly due to tobacco smoking. After uncomplicated microcoil embolization of the left internal mammary artery, the patient experienced no further episodes of haemoptysis. Microcoil embolization can be used successfully to treat massive haemoptysis related to proliferated and enlarged bronchial arteries in transplanted lungs with bronchial artery revascularization.

Bronchial Arteries↗

PubMed1997

Double-homograft repair of truncus arteriosus with severe truncal valve dysfunction.

An infant with truncus arteriosus and severe dysfunction of the truncal valve including both stenosis and insufficiency successfully underwent primary repair. This included the insertion of two separate valved homograft conduits. Early outcome has been excellent and the patient is doing well after 6 months with only echocardiographic evidence of mild aortic valve regurgitation. Double-homograft repair is a realistic option in cases of truncus arteriosus with severe malformation of the truncal valve.

Echocardiography, Doppler↗

PubMed1997

Surgical and arteriographic results of bronchial artery revascularization in lung and heart lung transplantation.

BACKGROUND: On the basis of our experience with bronchial artery revascularization (BAR) in lung transplantation since its introduction in Copenhagen in 1992, a description of the surgical anatomy of the bronchial arteries and the results of attempted BAR in these patients will be presented. METHODS: Since June 1992, BAR was performed in 50 en bloc double lung, six single lung, and nine heart-lung transplantations. The location, number, type, and size of each bronchial artery identified and revascularized were recorded. Our choice of conduit for BAR was the internal mammary artery. Routine internal mammary-bronchial arteriography was performed early after the transplantation to evaluate the result of BAR. All arteriograms were carefully studied together with the surgical records. The arteriographic results after attempted BAR were classified as complete, incomplete (bilateral, hemilateral, or poor), or failed. The surgical and arteriographic anatomy of the bronchial arteries has been described, and nomenclature for the as yet unnamed bronchial arteries has been developed. RESULTS: During surgery 128 bronchial arteries were identified in the descending aorta of the 64 donor lung blocs. Internal mammary-bronchial arteriography was performed in 53 patients. BAR was complete in 32, incomplete in 18, and failed in 3. The number of bronchial arteries identified and revascularized in each case increased with experience. The central and intrapulmonary bronchial artery anatomy was described, and different patterns have been identified. CONCLUSIONS: Bronchial artery identification is reliable, but a learning process is involved. BAR is possible with a high success rate. Complete BAR is an obtainable goal in most cases.

Anastomosis, Surgical↗

PubMed1997

Direct bronchial artery revascularization and en bloc double lung transplantation--surgical techniques and early outcome.

BACKGROUND: Lung transplantation including direct bronchial artery revascularization (BAR) has produced promising early results in small clinical series. METHODS: In Copenhagen primary en bloc double lung transplantation with BAR, with the left mammary artery used as conduit, has been performed in 47 patients from 1992 to the end of 1995. After introduction of the bloc into the recipient, the mammary-to-bronchial artery anastomosis is performed as the first anastomosis, allowing perfect exposure and early reperfusion. Internal mammary-bronchial artery arteriography has been performed routinely after operation. RESULTS: Bronchoscopic examination performed in all patients documented normal airway healing in 42, disturbed in two, and complicated in three. Arteriography performed in 42 patients demonstrated complete BAR in 25, incomplete in 15, and failed BAR in 2. Failed BAR was associated with complicated airway healing. The 1- and 2-year survival rate (Kaplan-Meyer) is 83%. Eleven patients have died, only one within 30 days. The total incidence of bronchiolitis obliterans syndrome at 3 years (with Kaplan-Meier technique) is 33%. Successful BAR has also been performed with an adjusted technique in a limited number of heart-lung and single lung transplantations. Our total experience of BAR in any type of lung transplantation includes 65 patients with an arteriographic BAR success rate of 94% (50 of 53 examined patients). CONCLUSIONS: Experience has improved the surgical technique and has made BAR reliable and safe, be it double lung, single lung, or heart-lung transplantation. Early results are good, but only follow-up will show if long-term results after lung transplantation will be improved by BAR. Already today, en bloc double lung transplantation with BAR is a viable alternative to sequential bilateral lung transplantation.

Anastomosis, Surgical↗