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Biomedical subjects

M Brandt

Publications and source records attributed to M Brandt.

At least 37 records · Page 2Linked to original sources
PubMed2000

Influence of special surfactants on the microbial degradation of mineral oils.

Various surfactants belonging to the group of fatty acid-acylated amino acids were tested for their ability to accelerate the microbial degradation of mineral oil. Of the lauric acid-acylated amino acids, aliphatic acids and histidine were found to be the most suitable. By the aid of these compounds additional 20-60% of a residual oil fraction could be degraded. The longer the chain of the fatty acid moiety, the more effective the surfactants are. Natural L-amino acids were more effective than their D-configuration. Since the special surfactants are easily biologically degradable, multiple replenishment is required in long-term experiments. The faster, more complete degradation of mineral oil is caused solely by interfacial activity; the growth of biomass due to the function of surfactants as substrate had no effect.

Biodegradation, Environmental↗
PubMed2000

9:45-10:00. Superimposition of EBCT Determined Coronary Calcium Deposits onto Myocardial PET Perfusion Images by Rubidium-82 and Nitrogen-13 Ammonia for Assessment of Flow Limiting Defects.

Calcium localization by Electron Beam CT (EBCT) in the coronary arteries is becoming an important non-invasive method for screening asymptomatic patients for early coronary atherosclerosis. However, the relationship between coronary artery calcium deposits and myocardial perfusion abnormalities has not been established. We have developed software to superimpose location of coronary calcium by EBCT onto PET myocardial perfusion images, so that we can determine the role of location and amount of calcium in the arteries to flow-limiting perfusion defects by PET.EBCT and PET transaxial images are each first converted to three-dimensional arrays of 1 mm voxels. The resulting two image volumes sets are displayed so that a vertical line can be drawn from the clavicle to the spine for proper rotation of the body. The rotated images are then displayed superimposed and are shifted in the vertical, horizontal, and the long axis directions to co-register the EBCT and PET images. The EBCT images are windowed for calcium Houndsfield numbers and calcium location is added to the PET images as a maximum intensity value in the image. The modified PET image volume is then translated back to the PET data format and reprocessed using cardiac analysis software such that the calcium location is superimposed on the PET myocardial perfusion images.Preliminary results of the PET-EBCT superimposition program correlate with location of coronary calcium by EBCT and PET perfusion defects following stress. This technique may be useful for identifying flow-limiting calcium deposits in the coronary arteries.

Journal Article↗
PubMed2000

Thyroperoxidase (TPO) immunostaining of the solitary cold thyroid nodule.

OBJECTIVE: To evaluate the value of immunostaining using the monoclonal antibody (MoAB47) against thyroperoxidase (TPO) in distinguishing between benign and malignant tumour cells in fine needle aspiration cytology (FNAC) samples obtained from a solitary cold nodule of the thyroid gland for the purpose of strengthening the indication for thyroid surgery. DESIGN: A prospective, immunocytochemical study of FNACs taken from patients with solitary cold thyroid nodules who presented to Rigshospitalet, Copenhagen, Denmark, during the period April 1993 to May 1996. The first sample series was taken perioperatively in order to test the utility of the method. In the second part of the study samples were obtained preoperatively by ultrasonic guided aspiration. Tissue sections from the nodules obtained during a subsequent operation served as controls. PATIENTS: One hundred and eighty-one patients, 150 women and 31 men, were studied. The age range was 14-89 years with a median age of 44 years. Fifty-seven patients were excluded from the study for various reasons leaving us with a total of 124 nodules from 124 patients for final evaluation. METHODS: FNAC cells and corresponding nodular tissue were stained by immunocyto- and immuno-histochemistry using MoAb47 and by routine staining methods. Samples were considered benign if 80% or more of the epithelial-looking cells of both the FNACs and the histological tissue sections of the nodule were stained by TPO. Consequently, samples were considered malignant if more than 20% of the epithelial-looking cells failed to stain for TPO. Routinely stained tissue cells and sections served as diagnostic controls. RESULTS: A pattern with negative TPO staining was found in all lesions which, by conventional histological staining, were subsequently proven to be malignant. A universal and reliable, positive TPO staining pattern was found in all subsequently proven benign lesions, with the exception of one out of 26 follicular adenomas. This gave the method a sensitivity of 1.0 (negative TPO staining = malignancy in 27 out of 27) and a specificity of 0.99 (positive TPO staining = benign lesion, in 96 out of 97). Positive and negative predictive values were 0.96 and 1.00 respectively. CONCLUSION: Thyroperoxidase immunostaining of fine needle aspirates from solitary, scintigraphically cold nodules of the thyroid gland has proved to be an important and reliable diagnostic tool for distinguishing between benign and malignant nodules. Thus, patients might be spared further surgery if not otherwise indicated.

Adolescent↗
PubMed1999

A substrate combinatorial array for caspases.

An efficient strategy for the synthesis of a tetrapeptidyl substrate combinatorial array directed toward the caspases is described. Testing of this array with caspases 1 and 4 gave substrate hydrolytic profiles characteristic of each caspase, and permitted the identification of efficiently processed substrates. A comparison of this approach to that using a positional scanning library is presented.

Caspase 1↗
PubMed1999

The Dresden approach for complete multivessel revascularization.

BACKGROUND: In a prospective clinical trial, a group of patients receiving less invasive surgical procedure, including minithoracotomy in combination with cardiopulmonary bypass (group 1), was compared to a group of patients receiving conventional bypass surgery (group 2) for the treatment of coronary artery disease. METHODS: Group 1 included 85 patients (71 men, 14 women, aged 39 to 82 years, median 61.1 +/- 9.0 years); group 2 included 53 patients (38 men, 15 women, aged 51 to 79 years, median 62.0 +/- 6.1 years). RESULTS: There were no perioperative deaths in the whole series of patients. Time of operation was 256 +/- 43 minutes in group 1 and 150.0 +/- 53.6 minutes in group 2. Hospitalization was 6.0 +/- 1.4 days and intensive care unit stay 1 day for both groups. Back pain assessment on postoperative day 3 showed less pain in group 1. Three-month follow-up revealed ischemia in stress electrocardiogram in 2 patients (2.5%) in group 1 and in 2 patients (4.1%) in group 2. Coronary angiograms confirmed the stress-electrocardiogram findings. CONCLUSIONS: Surgical results are equal for both techniques. Even though time of operation is longer in patients receiving less invasive procedures, intensive care unit stay and hospital stays are the same length. Early postoperative back pain is less in group 1 and combined with faster convalescence.

Adult↗
PubMed1999

Polyethylene wear, osteolysis and acetabular loosening with an HA-coated hip prosthesis. A follow-up of 94 consecutive arthroplasties.

We have followed up for a period of seven to nine years 100 consecutive arthroplasties of the hip in which an entirely HA-coated implant had been used. The clinical results were excellent and bony incorporation was extensive in all components. No stem became loose or subsided but five cups were revised because of loosening after 3.8 to 5.5 years, having functioned painlessly and shown radiological ingrowth. Revision procedures because of excessive polyethylene wear have been performed on 18 hips and are planned for six more. Two eroded metal backings with worn-through polyethylene were exchanged; six hips showed metallosis without polyethylene wear-through. There were two cases of granulomatous cysts in the groin and 66 hips had osteolysis located periarticularly, in the greater trochanter or in the acetabulum.

Acetabulum↗
PubMed1999

Thyrotropin stimulates specifically the expression of the autoantibody binding domains of the thyroperoxidase molecule.

To get some insight on the in vitro effect of TSH on the expression of two thyroid specific antigens (thyroglobulin (Tg) and thyroid peroxidase (TPO)) on the cell surface of cultured human thyroid cells an indirect immunofluorescence-activated cell sorter (FACStar IV, Becton-Dickinson) was used. Only half of the cultures responded to TSH by increased surface expression of the thyroid specific antigen Tg. In these cells, TSH stimulation of TPO expression showed a difference in epitopes recognized by murine monoclonal antibodies. Epitopes of domain D, recognized by monoclonal antibody 1, 30, 40 and 53 which are not involved in autoimmunity, were unaffected by TSH stimulation, (n = 2-10). In contrast, TSH regulated the surface expression of the TPO epitopes recognized by monoclonal antibody 15, 18, 24 and 60, which are known to be related to the serum autoantibody binding domain of TPO, (n = 6-8; p < 0.05). This indicated that increased activity of the thyroid cells selectively stimulated the expression of autoantigenic epitopes on the cell surface and supports the concept that increased cellular activity might predispose to the autoimmune processes leading to autoimmune thyroid disease.

Animals↗
PubMed1999

Coronary artery bypass grafting via median sternotomy or lateral minithoracotomy.

OBJECTIVES: In order to evaluate the benefit provided through less invasive surgical techniques for the treatment of multivessel coronary artery disease, a prospective clinical trial was started. METHODS: Group 1 included 53 patients (38 males, 15 females, age 51-79 years, mean 62.8 +/- 6.1 years) receiving conventional bypass surgery, group 2 included 69 patients (59 male, 10 female, age 43-82 years, mean 61.9 +/- 8.6 years) receiving less invasive surgical procedure including minithoracotomy in combination with cardiopulmonary bypass. RESULTS: No perioperative death occurred in the whole series of patients. Time of operation was 267 +/- 61 min in group 2 and 162.9 +/- 53.6 min in group 1. Intensive Care Unit stay was 1 day for both groups and Hospitalization 6.9 +/- 6.0 for group 1 and 7.5 +/- 2.6 days for group 2. Perioperative bleeding was less in group 2 (P > 0.01). Back and chest pain assessment on postoperative day 3 showed less pain in group 2 (P < 0.05). Three-month follow-up revealed ischemia in stress electrocardiogram in two patients (3.8%) in group 1 and in 2 patients (2.9%) in group 2. Coronary angiograms confirmed the stress ECG findings. There was one (1.4%) redo operation in group 2 and two (3.8%) in group 1. CONCLUSIONS: Both techniques are equal efficient. Even though time of operation is longer in patients receiving less invasive procedure, intensive care unit stay and hospitalization is exactly as long. Patients receiving minimally invasive surgery bleed less and have less pain early postoperatively.

Adult↗
PubMed1998

Minimally invasive surgical treatment of coronary artery multivessel disease.

BACKGROUND: If coronary artery multivessel disease is the target of a minimally invasive procedure, either median sternotomy or cardiopulmonary bypass can be avoided. METHODS: We used an alternate technique instead of minithoracotomy and cardiopulmonary bypass to treat 102 patients (82 men, 20 women; age range, 39 to 82 years; median, 61.0 +/- 8.9 years) for coronary artery single-vessel, double-vessel, or multivessel disease between November 1996 and January 1998. Twenty-nine patients (22 men, 7 women; age range, 46 to 78 years; median, 69.0 +/- 8.4 years), who were in a high-risk group for the development of perioperative complications because of the use of cardiopulmonary bypass, received median sternotomy and a beating heart procedure using the Octopus stabilizing technique. The left anterior descending coronary artery was the target vessel in all patients except for 1, in whom the left internal mammary artery was used. RESULTS: There was no intraoperative death in either series. In the beating heart group (Octopus) 2 patients died on postoperative day 31 and 35, respectively, of postoperative pneumonia. CONCLUSIONS: Both techniques present safe alternative procedures to conventional coronary artery bypass grafting in patients with coronary artery multivessel disease.

Adult↗
PubMed1998

Experiences with a minimally invasive surgical technique for the treatment of coronary artery multivessel disease in 100 patients.

OBJECTIVE: The treatment of coronary single vessel disease under minimally invasive surgical conditions was followed by the treatment of coronary multivessel disease using a new technique. METHODS: Using this technique 100 patients (80 male, 20 female, median age 61.0+/-8.9 years, ranged from 39 to 82 years) with coronary single vessel disease, double vessel disease or multivessel disease were treated between November 1996 and December 1997. Via a small (6-9 cm) left lateral chest incision in the second or third intercostal space, the left internal thoracic mammary artery (LIMA) was harvested and access to the central portion of the heart including the ascending aorta was obtained. In parallel, saphenous vein segments were harvested. Arterial cannulation was instituted via the ascending aorta, thus avoiding retrograde flow. In all patients except three the LIMA was used for the left anterior descending artery (LAD). In addition vein grafts were used for revascularization of the other coronary arteries. All cardiac anastomoses were performed during cardioplegic arrest after external aortic cross clamping and antegrade application of cardioplegia. RESULTS: No death or intraoperative complications were observed in this series. The median hospital stay was 6.0+/-1.4 days (median+/-SEM). Postoperative complications were reexplored for bleeding (n = 1), delayed wound healing (n = 2), wound infections (n = 4), lymphatic fistulas (n = 4), and a chest wall hernia (n = 1). CONCLUSIONS: This minimally invasive surgical technique presents a safe alternative to conventional coronary artery surgery avoiding sternotomy related complications and decreasing hospital stay and morbidity.

Adult↗
PubMed1998

Ischemic preconditioning as an adjunct to crystalloid or blood cardioplegia for myocardial protection in routine coronary surgery.

Experimental preconditioning is commonly regarded as a powerful protective phenomenon in case of subsequent ischemia. However, little is known about the applicability of preconditioning as an adjunct to cardioplegic myocardial protection in routine coronary surgery. For this reason, a prospective clinical study (611995 to 4/1996) was initiated to evaluate normothermic ischemic preconditioning prior to crystalloid or cold blood cardioplegic arrest. Preconditioning was performed in two cycles of 5 min ischemia and 10 min reperfusion. Four groups of 7 patients each were compared regarding release of troponin T, creatine kinase-myocardial isoform (CK-MB), lactate, and total CK in coronary sinus effluents over a 12-hour period. In the absence of perioperative myocardial infarction, there were no significant differences in these ischemic and metabolic parameters. Unexpectedly, the heed of postoperative pharmacological inotropic support was greater after preconditioning. These results may indicate that ischemic preconditioning as an adjunct to cardioplegic arrest may be associated with impairment of left-ventricular contractility, thus even exerting potentially detrimental functional effects. Overall, the proven beneficial effects of experimental preconditioning seem not to be directly transferable into the clinical settings.

Aged↗
PubMed1997

Treatment with monoclonal antibodies to ICAM-1 and LFA-1 in rat heart allograft rejection.

During allograft rejection, leukocyte infiltration in the graft is regulated by various adhesion molecules. Treatment with monoclonal antibodies to ICAM-1 and LFA-1 (CD11 a) induces specific tolerance after murine heart transplantation. In this study, we investigated the possibility of tolerance induction using these antibodies in a fully incompatible rat heart transplant model. Heterotopic, intra-abdominal heart transplantation was performed using Dark Agouti (DA) rats as donors and Lewis (LEW) rats as recipients. Group A (n = 6) received no immunosuppression and served as controls. In group B (n = 6) 500 micrograms/kg per day 1A29 (anti-ICAM-1) was administered intravenously (i.v.) for 5 days; group C rats received the same dosage of WT.1 (anti-CD11 a) i.v. for 5 days. In group D (n = 6), rats received combined i.v. administration of anti-CD11 a and anti-ICAM-1 (500 micrograms/kg per day of each, for 5 days. The antibodies used were monoclonal mouse anti-rat antibodies produced from hybridomas. Allograft survival was monitored by daily palpation of the graft. There was no statistically significant difference in allograft survival between the groups (A: 5.7 +/- 0.5 days; B: 5.7 +/- 0.5 days; C: 5.7 +/- 0.5 days; D: 6.2 +/- 0.4 days). Treatment with monoclonal antibodies to ICAM-1 and LFA-1 alone or in combination had no effect on allograft survival after heart transplantation between fully incompatible rat strains. We conclude that induction of tolerance using these antibodies seems inconceivable in human heart transplantation.

Animals↗
PubMed1997

Influence of bicaval anastomoses on late occurrence of atrial arrhythmia after heart transplantation.

BACKGROUND: The standard technique for orthotopic heart transplantation includes right and left atrial anastomoses, which potentially disturb the integrity of the donor atria. Consequently, electrophysiologic abnormalities such as atrial flutter and fibrillation may occur even late after heart transplanation. METHODS: Over a 3-year period, 39 heart transplantations were performed using a standard right atrial anastomosis (group A), and 40 were done using bicaval anastomoses (group B). In each group, data of 30 consecutive patients with a minimum follow-up of 9 months were reviewed retrospectively to assess the incidence of atrial arrhythmia after hospital discharge. RESULTS: Early postoperatively, there was no difference in the duration of temporary pacemaker requirement and incidence of permanent pacemaker implantation (group A, 7%; group B, 7%; not significant) between the two groups. In 12 patients in group A (40%), 16 episodes of atrial flutter and fibrillation were detected 20 to 205 days after heart transplantation. In group B, 1 patient (4%) suffered from atrial fibrillation on day 116 after the operation (p < 0.001). CONCLUSIONS: Preservation of the integrity of the right donor atrium by construction of bicaval anastomoses results in a significantly decreased incidence of atrial flutter and fibrillation after heart transplantation when compared with the standard technique.

Adult↗
PubMed1997

Anti-rejection prophylaxis by blocking selectin dependent cell adhesion after rat allogeneic and xenogeneic lung transplantation.

OBJECTIVE: Adhesion molecules regulate the infiltration of leukocytes into the graft during rejection after lung transplantation. The first step of the adhesion cascade is mediated by selectins. Sialyl-LewisX is a ligand of P-selectin. The purpose of the study was to evaluate SLX, a synthetic oligosaccharide analog of Sialyl-LewisX, for anti-rejection prophylaxis after allogeneic and xenogeneic left lateral, orthotopic rat lung transplantation. METHODS: In groups A and B, allogeneic lung transplantation was performed using fully incompatible rat strains (donors: Dark-Agouti (RT1a); recipients: Lewis (RT11)). In group A (n = 10), recipients recieved 200 microg/d SLX i.v. on day 0-4. Group B rats (n = 10) served as untreated controls. The animals were sacrificed on days 5 and 10, respectively. In groups C and D, xenogenic lung transplantation was performed using Gold Syrian hamsters as donors and Lewis rats as recipients. In group C (n = 10), recipients received 200 microg/d SLX i.v. on day 0-4. Group D rats (n = 10) served as untreated controls. The animals were sacrificed on days 2 and 5, respectively. Rejection was graded by histology from 0 (no rejection) to 5 (necrosis). By immunhistology, alveolar, interstitial CD11a, CD18 and VLA-4 positive leukocytes were counted. RESULTS: Histologically, there were a lower grade of rejection (A: 2.7 +/- 0.6; B: 4.0 +/- 0.0; P < 0.05) and fewer CD11a positive leukocytes (A: 66 +/- 27; B: 186 +/- 73; P < 0.05) on day 5 in the SLX-treated allograft group compared to the untreated group. In xenotransplantation, SLX also reduced the grade of rejection (C: 3.3 +/- 0.5; D: 4.7 +/- 0.5; P < 0.05) and the number of CD11a positive leukocytes (C: 145 +/- 22; D: 176 +/- 20; P < 0.05) on day 2. CONCLUSIONS: It is concluded, that the administration of SLX significantly reduces allograft rejection. After discontinuation treatment with SLX unmodified rejection appeared. SLX also modifies xenograft rejection, but to a lesser extent, and xenograft necrosis appeared during treatment in this model.

Animals↗
PubMed1997

Ischemic preconditioning prior to myocardial protection with cold blood cardioplegia in coronary surgery.

OBJECTIVE: Encouraging results on myocardial preconditioning in experimental models of infarction, stunning or prolonged ischemia raise the question whether preconditioning techniques may enhance conventional cardioplegic protection used for routine coronary surgery. METHODS: A prospective clinical trial was conducted to investigate the effect of additional ischemic normothermic preconditioning prior to cardioplegic arrest applying cold blood cardioplegia in patients scheduled for routine coronary surgery (3 vessel disease, left ventricular ejection fraction > 50%). Two cross clamp periods of 5 min with the hearts beating in sinus rhythm were applied followed by 10 min of reperfusion, each (n = 7, group I). Inducing moderate hypothermia cold blood cardioplegia was delivered antegradely. In control groups, cold intermittent blood cardioplegia (n = 7, group II) was used alone. Coronary sinus effluents were analyzed for release of creatine kinase (CK), CK-MB, lactate, and troponin T at 1, 3, 6, 9, and 12 h. In addition, postoperative catecholamine requirements were monitored. RESULTS: The procedure was tolerated well, and no perioperative myocardial infarction in any of the groups studied occurred. Concentrations of lactate tended to be higher in group I, but this difference was not significant. In addition, no significant differences for concentrations of CK, CK-MB, and troponin T were found. Following ischemic preconditioning an increased dosage of dopamine was required within the first 12 h postoperatively (group I: 2.63 +/- 1.44 microg/kg/min, group II: 0.89 +/- 1.06 microg/kg/min). CONCLUSIONS: Combining ischemic preconditioning and cardioplegic protection with cold blood cardioplegia does not appear to ameliorate myocardial protection when compared to cardioplegic protection applying cold blood cardioplegia alone. Inversely, contractile function seemed to be impaired when applying this protocol of ischemic preconditioning.

Biomarkers↗