Biomedical subjects

J Burkert

Publications and source records attributed to J Burkert.

8 recordsLinked to original sources

PubMed2006

Accuracy of angiography and Doppler ultrasonography in the detection of carotid stenosis: a histopathological study of 123 cases.

BACKGROUND: A prospective study was performed comparing the accuracy of digital subtraction angiography (DSA) and Doppler ultrasonography (DUS) stenosis findings with measurements on histological specimens. METHOD: DSA and DUS were used to evaluate carotid stenosis and were compared with measurements on histological specimens. Intact carotid plaques from 123 cases were removed in one piece during surgery. The specimens were histologically processed and examined in transverse sections. The smallest inner and correlating outer diameters were measured and the extent of stenosis was calculated. Carotid artery stenoses were compared and statistics done. Specimens in symptomatic cases were divided into 3 groups: stenosis 30-49% (Group 1), stenosis 50-69% (Group 2) and stenosis 70-99% (Group 3). Specimens in asymptomatic cases were divided into two groups: stenosis or=60% (Group B). FINDINGS: Wilcoxon paired tests revealed significant differences between DSA, DUS and measurements on histological specimens. In severe stenoses only, no significant difference was observed between stenosis measurement according to the European Carotid Surgery Trial (ECST) angiography methodology and measurements on histological specimens. The most pronounced differences were found between angiography methodology of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and measurements on histological specimens. When investigating how often preoperative measurement classified stenosis into the same Group of stenoses as postoperative measurement, DUS was the most accurate diagnostic tool. CONCLUSIONS: This study confirmed our previous results, i.e., angiography underestimates the degree of carotid artery stenosis. DUS seems to be more accurate in classifying stenoses into different groups to the extent of narrowing of the carotid arteries. These results make the position of angiography in diagnostic algorithm of carotid stenoses investigations even more questionable.

Angiography, Digital Subtraction↗

PubMed2006

Stem cells and cancer: an intimate relationship.

Tumour-wide 'omics' approaches have long held sway as the approach to identifying useful therapeutic targets. This view is changing with the realization that many, if not all, cancers contain a minority population of self-renewing stem cells, the cancer stem cells, which are entirely responsible for sustaining the tumour as well as giving rise to proliferating but progressively differentiating cells that are responsible for much of the cellular heterogeneity that is so familiar to histopathologists. Moreover, although many tumours probably have their origins in normal stem cells, persuasive evidence from the haematopoietic system suggests that genetic alterations in more committed progenitor cells can reactivate the self-renewal machinery, resulting in a further source of cancer stem cells. Thus, the bulk of the tumour is not the problem, and so the identification of cancer stem cells and the factors that regulate their behaviour are likely to have an enormous bearing on the way that we treat neoplastic disease in the future.

Bone Marrow Cells↗

PubMed2006

Allograft semilunar cardiac valves processing and cryopreservation - morphology in scanning electron microscope.

OBJECTIVE: The most important factors of long term clinical performance of biological heart valve prostheses are methods of processing and cryopreservation. That is why we decided to evaluate the impact of current Allograft Heart Valves (AHV) Bank protocol on valve tissue morphology. Scanning electron microscope (SEM) is a valuable tool for investigation of biological surfaces. In case of cardiac valves it is especially suitable for detection of fine changes in endothelial covering and underlying layers. MATERIAL AND METHODS: "Fresh" aortic and pulmonary AHV samples, harvested from "heart-beating" cadaveric donors, were compared with (1) tissue from AHV obtained from non heart-beating donors, (2) samples stored in 4 degrees C saline for 24 h, (3) antibiotic treated tissue for 24 h at 37 degrees C and finally (4) cryopreserved valves, stored in liquid nitrogen (-196 degrees C) for 6-38 months. All samples were dissected, dried with hexamethyldisilazane (HMDS), gold coated, studied and photographed by SEM (Tesla BS 301). RESULTS: Our alternative method of drying samples by the HMDS method proved to be suitable for thin membranes of human semilunar valves. We were able to detect early changes in the endothelium after harvesting, and denudation of the endothelial covering during preservation with and without freezing. CONCLUSION: SEM (using HMDS drying) along with other methods may be helpful for the morphological control of processing, cryopreservation and liquid nitrogen storage of AHV. According to the current findings we have to avoid washing of AHV in saline after harvesting.

Cryopreservation↗

PubMed2006

Initial single-center experience with sirolimus after lung transplantation.

BACKGROUND: Standard immunosuppression after lung transplantation includes calcineurin inhibitors, mycophenolate mofetil, and steroids. Long-term survivors of lung transplantation are often confronted with chronic kidney disease, by definition related to the intake of calcineurin inhibitors. Sirolimus has been increasingly proposed as an alternative immunosuppressive agent due to its absence of nephrotoxicity, which could be used in selected patients. METHODS: We prospectively administered sirolimus as an alternative to calcineurin inhibitors in 10 lung transplantation recipients with persistent drug nephrotoxicity. They were switched from tacrolimus to sirolimus. Four patients also had bronchiolitis obliterans syndrome. The conversion scheme consisted of an immediate stop of tacrolimus and an 6 to 8-mg loading dose of sirolimus, followed by 4 mg/d. After 5 days, the sirolimus dose was adjusted to maintain trough levels between 12 and 18 ng/mL or 6 and 12 ng/mL for combined sirolimus and tacrolimus. Patients were monitored for renal and graft function as well as clinical status. RESULTS: A significant decrease in creatinine was observed after 1 week of treatment (P = .011). Azotemia decreased after 1 month, remaining stable (P < .01). Pulmonary function tests did not show significant modification from before sirolimus, inception in patients with or without bronchiolitis obliterans syndrome. There were seven infections. One patient died of complications related to bronchiolitis obliterans. CONCLUSION: Sirolimus was a useful alternative immunosuppressant, allowing significant tacrolimus withdrawal in transplant recipients with renal impairment. Sirolimus administration allowed recovery of renal function with low morbidity; it was useful for rescue of chronic renal impairment after lung transplantation.

Bronchiolitis Obliterans↗

PubMed2006

[Simultaneous cardiac and thoracic operations].

BACKGROUND: Optimal surgical strategy in patients with combined disease of heart (mainly ischemic heart disease or critical valve disease) and other thoracic organs (mainly pulmonary carcinoma) is still controversial. METHODS: From 1997 to 2004, 13 simultaneous cardiac and thoracic operations were performed in 13 patients. Most of them were necessary for combinations of symptomatic coronary artery disease (CAD) and bronchogenic carcinoma (BCA). PATIENT CHARACTERISTICS: 11 patients showed CAD, mean preoperative LVEF was 44 %. SURGICAL PROCEDURE: Surgical exposure was performed via sternotomy in 10 patients, the rest of the patients underwent thoracotomy. Seven patients were operated on cardiopulmonary bypass, the others underwent an off-pump procedure. Eleven patients underwent CABG, mean number of anastomoses were 2.1 (range 1-4), two patients underwent aortic valve replacement. One patient underwent radical removal of pulmonary adenocarcinoma with local expansion into the left atrium. For the lung cancer lobectomy was necessary in 8, pneumectomy in 1, extirpation of multiple metastases in 1, resection of the trachea in 1 patient. Histological diagnosis was epidermoid carcinoma in 6, adenocarcinoma in 3, undifferentiated carcinoma in 1, metastasis of Grawitz tumor in 1, pneumoconiosis in 1 patient. RESULTS: No patient died in hospital. One patient had to be re-explored for bleeding. Mean blood loss, duration of intubation and length of hospital stay were not different from other patients who underwent cardiac operation only. CONCLUSION: In accordance with the majority of the data published in the literature, combined procedures did not negatively influence hospital morbidity and mortality. Simultaneous operations eliminate the necessity of a second operation and do not delay the postoperative oncological therapy. Long-term results are primarily determined by histological diagnosis and by the extent of the tumor.

Aged↗

PubMed2006

Implantation of cryopreserved mitral allograft into the tricuspid position in an experimental study in sheep: technical aspects of implantation and immediate results evaluated by epicardial echocardiography.

AIMS: Cryopreserved mitral allograft valve (MAV) offers theoretical advantages over conventional mechanical or biological prostheses in tricuspid position, especially in infectious endocarditis patients. MAV processing and tricuspid valve (TV) replacement in a sheep model is described. METHODS AND RESULTS: In 20 adult sheep, MAV were harvested, processed and cryopreserved. One month later, recipient's TV were excised and the MAVs were transplanted into the tricuspid position in 13 sheep, under general anaesthesia, via a right thoracotomy, with an extracorporeal circulation (ECC) and cardioplegic heart arrest. Both MAV papillary muscles were anchored into the right ventricular wall by transmural stitches and the MAV anulus was sewn into the recipient's tricuspid anulus. After weaning from ECC, the anatomy and function of the MAV in the tricuspid position was assessed by epicardial echocardiography. The average duration of the ECC was 58 minutes (42-88), the cardioplegic heart arrest was 36 minutes (28-45). Weaning from EEC was always uneventful. Right atrial & pulmonary artery pressure measurements and epicardial echocardiography documented good function of all MAVs. CONCLUSION: MAV remained mechanically strong enough for implantation into the tricuspid position. Reproducible technique of MAV transplantation into the tricuspid position with excellent early postoperative haemodynamic performance was developed.

Animals↗

PubMed2006

[Resection of metastatic nondifferentiated carcinoma of sternum with thoracic wall reconstruction and simultaneous myocardial revascularization for ischemic heart disease--case report].

Authors offer the case report of a patient with metastatic non differentiated carcinoma of sternum simultaneously suffering from ischemic heart disease. The patient underwent actinotherapy & hyperthermia followed by resection of sternum and coronary artery bypass grafting in one session. Chest wall defect was closed by means of latissimus dorsi muscle rotation. Postoperative palliative chemotherapy started 16 weeks postoperatively. Primary tumor was not found, neither preoperatively nor during the 36 months' postoperative remission.

Bone Neoplasms↗

PubMed2005

[Ischemic mitral regurgitation. Clinical review emphasizing the surgical treatment].

Ischemic mitral regurgitation represents comparatively frequent complication of the myocardial infarction. Presence of the ischemic mitral regurgitation has a negative effect on the immediate mortality after the myocardial infarction and on the long-term survival. Ischemic mitral regurgitation is a functional, not structural impairment of the mitral valve and it is caused by altered geometry of the left ventricle. The article deals with the development and pathophysiology namely of the chronic ischemic mitral regurgitation and with the contemporary potential of surgical treatment of that serious complication of the ischemic heart disease.

Chronic Disease↗