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Biomedical subjects

M Beer

Publications and source records attributed to M Beer.

At least 55 records · Page 3Linked to original sources
PubMed1999

[CINE-MRT for the study of the effects of regional left ventricular wall motion disorders on global heart function after a myocardial infarct and revascularization].

PURPOSE: To determine changes in global cardiac function and mass caused by infarct-associated regional wall motion abnormalities and to compare the changes after revascularization in patients with and without improvement of regional contractility. MATERIALS AND METHODS: 21 patients with regional left ventricular wall motion abnormalities and associated coronary artery stenoses requiring revascularization were examined with a Cine FLASH-2D sequence 26 +/- 12 days after their first myocardial infarction and re-examined three months after revascularization. Regional contractility and volumes and masses of both ventricles were determined. RESULTS: After revascularization, regional wall motion improvement led to decreased left ventricular volumes and improved ejection fractions, whereas patients with persisting wall motion defects showed unchanged left ventricular functional parameters. Comparing both groups of patients, the patients with improvement of regional contractility revealed lower end-systolic volumes and higher ejection fractions at follow-up. Cardiac masses and right ventricular parameters were not different, patients with a depressed right ventricular ejection fraction showed improvement at follow-up. DISCUSSION: After myocardial infarction, revascularization of the infarct-related coronary artery leads to an improvement of left ventricular function only if there is also an improvement of regional contractility. An effect on right ventricular function was not observed three months after the first small- or middle-sized myocardial infarction.

Adult↗
PubMed1999

[The quantification of energy-rich phosphates in healthy and damaged heart muscle by SLOOP 31P-MR spectroscopy. Spatial localization with optimal pointspread function].

PURPOSE: A quantitative 31P-MR-spectroscopic technique was used to assess the energy metabolism in healthy and diseased myocardium. METHODS: 31P spectra were acquired on a 1.5 T scanner using a 3D-chemical shift imaging technique. Based on the anatomical information provided by 1H images, SLOOP (Spatial Localization with Optimal Pointspread Function) allows to obtain spectra from defined compartments. With SLOOP a free voxel shape with adaption to anatomic structures, e.g. the myocardium, is possible. Absolute values for phosphocreatine (PCr) and adenosine triphosphate (ATP) were determined using an external standard. RESULTS: 31P-spectra showed only minimal contamination by surrounding tissue. The standard deviation for the determined values of healthy volunteers was low. Compared to healthy volunteers, reduced PCr and ATP concentrations were seen for dilative cardiomyopathies and coronary artery disease and unchanged concentrations were observed for hypertensive heart disease. CONCLUSION: 31P-MR spectroscopy with SLOOP allows a non-invasive, quantitative analysis of cardiac energy metabolism.

Adenosine Triphosphate↗
PubMed1999

[3-dimensional MR coronary angiography in the navigator technic for the primary diagnosis of coronary heart disease: a comparison with conventional coronary angiography].

PURPOSE: Evaluation of three-dimensional MR coronary angiography with the navigator technique for the primary diagnosis of coronary artery disease (CAD) in patients with chest pain. MATERIALS AND METHODS: In this prospective study 20 patients with chest pain were examined with MR coronary angiography and conventional angiography. The three-dimensional MR coronary angiography was performed using a 1.5 T scanner with an ECG-triggered 3D-FLASH-sequence and retrospective respiratory gating in the navigator technique. The MR coronary angiography was evaluated by two radiologists blinded to the results of the conventional coronary angiography. RESULTS: One patient was excluded from further evaluation due to reduced image quality. Conventional coronary angiography excluded CAD in 8/19 patients, 11/19 patients overall showed 20 stenoses (> 50%) or occlusions. With MR coronary angiography, CAD was correctly excluded in 7 patients, one patient was false positive, one patient was false negative. 14/20 stenoses (> 50%) or occlusions were detected, 5 stenoses were diagnosed false positive. Sensitivity and specificity for primary diagnosis of CAD or detection of coronary artery stenoses were 91% and 88% or 70% and 91%, respectively. DISCUSSION: Using MR coronary angiography with the navigator technique in the primary evaluation of CAD, the diagnosis of stenoses or occlusions of the main coronary arteries is feasible.

Adult↗
PubMed1999

Three-dimensional MR coronary angiography using the navigator technique compared with conventional coronary angiography.

OBJECTIVE: We evaluated the diagnostic accuracy of three-dimensional (3D) MR coronary angiography with the navigator technique for the detection of coronary artery stenoses in comparison with that of conventional radiographic angiography. SUBJECTS AND METHODS: Thirty patients with coronary artery disease were examined with an ECG-triggered 3D fast low-angle shot sequence using retrospective respiratory gating and the navigator technique on a 1.5-T MR scanner. The data set was evaluated as a 3D view with a surface rendering technique. RESULTS: Imaging of the proximal coronary arteries was possible in all patients. The average visualized lengths of the left main, left anterior descending, left circumflex, and right coronary arteries were 1.9+/-0.5 cm (mean +/- SD), 5.2+/-2.3 cm, 4.2+/-1.9 cm, and 5.2+/-2.5 cm, respectively. Irregular breathing reduced image quality in seven of the 30 patients, making diagnosis of stenoses impossible. In the 77% of patients whose examinations resulted in high-quality images, the sensitivity and specificity for detection of significant stenoses and occlusions in all four main coronary arteries were 81% and 89%, respectively. CONCLUSION: The navigator technique allows reproducible imaging of the proximal course of coronary arteries. This technique obviates breath-hold studies, thus allowing more patients to be examined. In patients whose examinations resulted in high-quality images, significant coronary artery lesions could be seen. However, for widespread clinical use, further technical improvement is necessary to increase sensitivity and specificity.

Adult↗
PubMed1999

[Selection of BVDV genotype II isolates using a monoclonal antibody and FACS analysis].

The infection of cattle with the bovine viral diarrhea virus (BVDV) in Germany is gaining attention and guidelines for the "protection of cattle farms against BVDV infections" were passed in 1997. New investigations about the damages induced by BVDV infections as well as the new occurrence of so-called BVDV genotypes (BVDV I and II) made the problems to become aware. The newly described BVDV genotype considerably differs both genetically and antigenetically from the up to now known BVD-viruses (BVDV I). The subdivision in BVDV genotypes I and II is based on genomic differences, which are determined by sequence analyses of different parts of the viral genome. Here, we describe the classification of BVDV in genotypes using a monoclonal antibody and indirect immunofluorescence with flow cytometry (FACS) based analysis. The suitability of the mab WB160 (Central Veterinary Laboratory, Weybridge; UK) for the classification of both BVDV-genotypes was first checked using genetically defined BVDV isolates. While all BVDV I isolates (n = 20) reacted with high fluorescence signals, the mab WB160 could not detect any of the defined BVDV II isolates (n = 20). Subsequently, 505 BVDV field strains isolated between 1993-1997 were screened for both genotypes using the mab WB160 and FACS analysis. 33 (6.5%) of the BVDV isolates were classified as BVDV II.

Animals↗
PubMed1998

Laparoscopic nephrectomy: the experience of the laparoscopy working group of the German Urologic Association.

PURPOSE: The centers of the laparoscopy working group of the German Urologic Association collected data to prove the efficacy, safety and reproducibility of laparoscopic nephrectomy. MATERIALS AND METHODS: At 14 centers 482 laparoscopic nephrectomies have been performed until December 1996 via a transperitoneal approach in 344 (71%) and a retroperitoneal approach in 138 (29%). All 482 laparoscopic nephrectomies were performed by a total of 20 surgeons with an average of 24 procedures per surgeon (range 4 to 105). The indications for nephrectomy were benign renal pathology in 444 patients (92%), including renovascular disease in 28%, hydronephrosis in 20%, reflux nephropathy in 15%, chronic pyelonephritis in 12%, end stage nephrolithiasis in 11%, renal dysplasia in 4% and renal tuberculosis in 1%. Of the remaining 38 patients (8%) laparoscopic radical nephrectomy was performed for renal cell carcinoma in 5% and for upper tract transitional cell carcinoma in 3%. RESULTS: Operating time depended mainly on the pathology of the kidney (that is small dysplastic organ versus large hydronephrosis) and the learning curve of the surgeon. However, the average operating time did not vary significantly among the different centers (maximum 277.6 and minimum 81.9 minutes). Intraoperative or perioperative complications were noted in 29 patients (6.0%), including bleeding in 22 (4.6%), bowel injury in 3, hypercarbia in 2 and pleura lesion in 1 and pulmonary embolism in 1. The conversion rate was 10.3% (bleeding, bowel injury, difficult dissection), including 4 patients with renal tuberculosis, 2 with xanthogranulomatous nephritis, and 1 each following renal trauma and embolization. The re-intervention rate was 3.4% due to bleeding in 6 cases, abscess formation in 3, intestinal stenosis in 2 and a pancreatic fistula and port hernia in 1. Mean hospital stay was 5.4 days. CONCLUSIONS: Laparoscopic nephrectomy has become a well established procedure in those urology departments focusing on laparoscopy. The indications and results are reproducible at these centers. However, for patients with severe perinephritis (that is renal tuberculosis, xanthogranulomatous nephritis, posttraumatic atrophy) a higher likelihood of open conversion must be considered.

Adolescent↗
PubMed1998

In vitro effects and clinical evaluation of a human chorionic gonadotrophin preparation in acute leukemia.

Commercial human chorionic gonadotrophin (HCG) preparations decrease the tumorigenicity of human tumors in immunodeficient mice and induce apoptotic cell death in animal tumor models. Preliminary studies in humans have demonstrated tumor regression in patients with Kaposi's sarcoma given intralesional injections of HCG. To further evaluate HCG's antitumor activity we conducted in vitro and clinical evaluations of HCG in acute myeloid leukemia (AML). In HL-60 leukemic cell lines, a 20-40% inhibition of cell density was demonstrated by trypan blue exclusion method at low concentrations of an HCG preparation (2 x 10(-3)-2 x 10(-2)). Similar concentrations also resulted in a reduction in the proportion of cells in G2M phase of the cell cycle, as well as enhanced differentiation compared to control cells. Fifteen patients with advanced AML with marrow blast counts >30%, and five with marrow blast counts between 10 and 26% were given daily subcutaneous injections of HCG 2-4 IU and oral levamisole 50 mg weekly. Five patients with absolute blast counts in the blood ranging from 0 to 3500/microl and percent blasts in the marrow ranging from 16 to 81% were observed to have no progressive increase in either marrow or peripheral blast counts for 70-121 days. One patient with a pretreatment blast count of 10% in the marrow, no circulating blasts and minor cytopenias had a decrease in marrow blasts to less than 5% which has persisted at 550 days. No significant improvement from baseline levels of neutrophils, hemoglobin or platelets were observed in any nl the patients treated. Increases in apoptotic cell death were observed in over 50% of patients' cells with some demonstrating peak levels similar to experiences in patients treated with DNA-damaging chemotherapy. A decreased expression of bcl-2 was seen in the majority of patients ranging from 6 to 62%. These new observations suggest that HCG preparations may inhibit leukemic cell growth through enhancement of cell death mechanisms and could be used in judicious combinations with other approaches. The results confirm the pro-apoptotic effects of HCG preparations reported in patients with Kaposi's sarcoma. Identification of the active component of HCG preparations and further understanding of its growth modulatory action will be important in its development as a clinically useful agent.

Acute Disease↗
PubMed1998

[3-dimensional MR coronary angiography with navigator technique: imaging of the proximal course of a coronary artery anomaly].

Congenital coronary artery anomalies are found in 0.3 to 1.3% of patients and can cause ischemic heart disease or sudden cardiac death, especially if the anomalous coronary artery courses between the aortic root and the pulmonary artery. Identification of the anatomic course of the anomalous vessel is not always feasible by conventional radiographic coronary angiography. With MR coronary angiography not only flowing blood but also the vessel anatomy can be imaged. In previous studies, a two-dimensional gradient-echo sequence during breathhold was used demanding both cooperation of the patient and operator skill. The navigator technique reduces respiratory artifacts by retrospective respiratory gating on the diaphragm's position, obviating the need for breathhold studies. Furthermore, the three-dimensional MR coronary angiography enables post-processing using the Volume Rendering Technique for evaluation of three-dimensional view. We report on the use of this technique for the identification of the course of anomalous coronary arteries in two patient cases.

Artifacts↗
PubMed1997

Equine herpesvirus 1 mutants devoid of glycoprotein B or M are apathogenic for mice but induce protection against challenge infection.

Equine herpesvirus 1 (EHV-1) mutants devoid of the open reading frames (ORFs) of either glycoprotein (g) B or M were constructed and tested for their immunogenic potential in a murine model of EHV-1 infection. The mutant viruses were engineered using the virulent EHV-1 strain RacL11 or the modified live vaccine strain RacH by inserting the Escherichia coli LacZ gene into the viral ORFs. RacL11-infected mice showed signs typical of an EHV-1 infection, whereas mice infected with the EHV-1 gB- or gM-negative mutants or with RacH did not develop disease. No difference in the pathogenic potential of RacL11 gB- and gM-negative viruses was observed after application of either phenotypically completed or negative viruses. However, revertant RacL11 viruses in which the gB or gM gene had been restored caused EHV-1-related symptoms that were indistinguishable from those induced by RacL11. Mice that had been immunized with phenotypically negative gB- and gM-deficient EHV-1 were challenged with the RacL11 virus 25 days after immunization. Mock-immunized mice developed EHV-1 disease and high virus loads in their lungs were observed. In contrast, mice developed not exhibit EHV-1-caused disease. It was concluded (i) that deletion of either gB or gM abolished the virulence of strain RacL11 and (ii) that immunization with gB- or gM-negative EHV-1 elicited a protective immunity that was reflected by both virus-neutralizing antibodies and EHV-1-specific T-cells in spleens of immunized mice.

Animals↗
PubMed1997

Cytotoxic T-lymphocyte responses in cattle infected with bovine viral diarrhea virus.

A system for a reproducible in vitro restimulation of bovine viral diarrhea virus (BVDV)-specific cytotoxic T-cells (CTL) was developed. Lymphocyte cultures of BVDV-immunised cattle were stimulated with infectious BVDV isolate PT810 and recombinant bovine interleukin-2 for 12 to 25 days. A specific lysis of Concanavalin A-stimulated BVDV-infected autologous target cells was observed, whereas allogeneic BVDV-infected target cells were only marginally lysed as detected by flow cytometry. BVDV-specific lymphocyte transformation was further characterised by the expression of bovine lymphocyte activation antigens and bovine MHC class-II molecules. Secondary stimulation of CTL was influenced by in vitro production of BVDV-specific neutralising antibodies, which were secreted exclusively in BVDV-inoculated lymphocyte cultures of immunised cattle. These results demonstrate the presence of CTL in peripheral blood mononuclear cells (PBMC) of immunised cattle which can kill autologous BVDV-infected antigen-presenting cells after in vitro restimulation.

Animals↗
PubMed1997

Genomic (5'UTR) and serological differences among German BVDV field isolates.

Isolates of bovine viral diarrhoea virus (BVDV) collected in Germany were examined for their genomic heterogeneity in sequences from the 5'untranslated region (UTR) of the viral genome. Polymerase chain reaction (PCR) tests based on the 5'UTR and the region coding for the NS2-3/4A polypeptide were used to differentiate between BVDV I and BVDV II genotypes. Eleven out of 96 BVDV-isolates were identified as BVDV II. Virus neutralization tests with BVDV I- or II-specific antisera raised in cattle were done. The mean titers were reduced by 7.2-fold (BVDV I-antiserum versus type II-isolates) or 35-fold (BVDV II-antiserum versus type I-isolates) when using the respective heterologous virus.

Animals↗
PubMed1997

Single and double autotransplants for relapsing/refractory Hodgkin's disease: results of two consecutive trials.

To evaluate a strategy of one cycle of dose-intensive chemotherapy for patients with Hodgkin's disease in sensitive relapse and two cycles for those with refractory disease, 122 patients received dose-intensive chemotherapy followed by autotransplant in two consecutive studies. Patients with refractory disease were offered a second transplant with different conditioning in the absence of progression or excessive toxicity. CR was present after treatment in 46% while 16% died in the peritransplant period. Of 41 patients with primary refractory disease and 42 with refractory relapse, 24 and 21 respectively received a second cycle. Of these 45 refractory patients, 12 were in CR and 11 in PR after the first cycle and 10 of these 11 in PR achieved a durable CR with the second transplant. The CR rate is 37% in patients with refractory relapse and 19% in those with primary refractory disease. At a median follow-up of 4 years, median survival is 45 months. Progression-free survival of the refractory patients who could receive a second cycle was similar to that of patients with sensitive disease. A sequential transplant strategy is feasible. A subgroup of patients with refractory disease can achieve long-term survival after sequential BMT.

Adolescent↗
PubMed1997

A randomized trial of high- vs standard-dose mitoxantrone with cytarabine in elderly patients with acute myeloid leukemia.

To evaluate the efficacy and tolerability of a high-dose mitoxantrone-based induction regimen without consolidation therapy in patients over age 60 with newly diagnosed acute myeloid leukemia (AML), 54 patients aged 60-83 were randomized to receive mitoxantrone, either 80 mg/m2 on day 2, or 12 mg/m2 on days 1-3 in addition to cytarabine, 3 g/m2 on days 1-5. Significant toxicity included mucositis, diarrhea, transient hyperbilirubinemia and cardiac events. No difference in toxicity was observed between the two dosage regimens. Overall, 27 patients achieved a complete remission (CR), 16/28 CR in the high-dose and 11/25 in the lower-dose group. Induction death occurred in 11 patients, three in the high-dose and eight in the low-dose arm. Actuarial median survival was 6 months for the low-dose and 9 months for the high-dose group, and the respective relapse-free survival is 3 and 5 months. The observed differences in outcome were not statistically significant. patients in both arms of this trial, who received no consolidation, appear to have response and survival rates equivalent to those of standard-dose induction with repetitive consolidation. This approach might offer elderly patients equivalent outcome with fewer days of treatment, presumably enhancing quality of life.

Acute Disease↗