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Biomedical subjects

L Burger

Publications and source records attributed to L Burger.

At least 19 recordsLinked to original sources
PubMed1998

An Sp1-binding site and TATA element are sufficient to support full transactivation by proximally bound NS1 protein of minute virus of mice.

The minute virus of mice (MVM) P38 Sp1-binding site and TATA box, inserted in an otherwise heterologous plasmid background, could be transactivated to high levels by the MVM NS1 protein targeted proximally to these sequences, demonstrating that these core promoter regulatory elements are sufficient to support essentially wild-type levels of NS1-transactivated expression and suggesting that NS1 may act directly or indirectly with Sp1 and or elements of the general transcription machinery. Accordingly, we show that bacterially generated NS1 can interact strongly, independent of nucleic acid bridging, and most likely directly with Sp1 in vitro and can associate, in a nucleic acid-independent manner, with endogenous Sp1 as it exists in a complex transcriptionally active murine nuclear extract NS1 achieves the same fold activation of an isolated TATA element over its low basal level and can also be demonstrated to interact efficiently and specifically with the general transcription factors TBP and TFIIA (alpha, beta) in vitro.

Animals↗
PubMed1998

Maximizing the hemodynamic benefit of enhanced external counterpulsation.

BACKGROUND: Enhanced external counterpulsation (EECP) has been demonstrated to be an effective treatment for angina and exertional ischemia in patients with coronary disease. HYPOTHESIS: It is hypothesized that the ability of EECP to enhance the recruitment or development of coronary collaterals in coronary artery disease may be determined by the relative magnitude of diastolic augmentation (DA) and systolic unloading (SU). This study examines the relation between the proposed EECP effectiveness ratio (DA/SU), as assessed by finger plethysmography, and changes in descending aortic flow as assessed by Doppler echocardiography in 15 patients during EECP. METHODS: Varying external cuff pressures (0-275 mmHg) were used to generate a range of DA/SU ratios. The effect on aortic antegrade systolic and retrograde diastolic flow was assessed by Doppler echocardiography to determine whether there was an optimal EECP effectiveness ratio that maximizes the hemodynamic effects of EECP. With increasing DA/SU there was an initial positive linear increase in both systolic and diastolic flow volume. Systolic flow maximized at an effectiveness ratio of 1.5 and diastolic flow at a ratio of 2.0 RESULT: Therefore, effectiveness ratios (DA/SU) in the range of 1.5-2.0 are optimal for maximizing the hemodynamic effects of EECP.

Adult↗
PubMed1997

Enhanced external counterpulsation as an adjunct to revascularization in unstable angina.

Enhanced external counterpulsation (EECP) is an effective noninvasive treatment for chronic stable angina. Despite intensive risk factor modification, a patient required two surgical coronary revascularizations and seven multivessel angioplasties over a 26-month period, demonstrating recurrent unstable angina and persistent thallium perfusion defects despite revascularization. Post EECP, angina was relieved, thallium defects were resolved and the patient has remained asymptomatic for 36 months.

Angina, Unstable↗
PubMed1996

Can angiographic findings predict which coronary patients will benefit from enhanced external counterpulsation?

Enhanced external counterpulsation is an effective treatment for chronic angina. Theoretical considerations predict greatest benefit in patients with at least 1 patent conduit in this group of 50 patients (all of whom improved clinically). Improvement in radionuclide stress perfusion imaging was seen in 80% of treated patients and was inversely related to extent of coronary disease.

Aged↗
PubMed1993

Prediction of sudden cardiac arrest: risk stratification by anatomic substrate.

The prognostic importance of coronary artery anatomy to specific outcomes including ventricular tachycardia/fibrillation was evaluated in 372 consecutive patients undergoing cardiac catheterization at University Hospital at Stony Brook between 1981 and 1984. The hypothesis that proximal left anterior descending artery narrowing before the first septal perforator had a specific relationship to survival was again tested in this cohort. The population was prospectively followed for 8 years, with all clinical management decisions made independently by the patient's primary or referring physician. Multivariate statistical and life table analyses were performed after comprehensive follow-up. Significant narrowing in the proximal left anterior descending artery was associated with an increased risk of sudden cardiac death (p = 0.0002). Abnormalities of contractility in the diaphragmatic segment of the left ventricle in addition to an elevation of the left ventricular end-diastolic pressure and the presence of congestive heart failure (p < 0.05) were other contributory variables. Outcome in patients with proximal left anterior descending coronary artery disease who underwent aortocoronary artery bypass to the artery demonstrated improved survival (p < 0.05). Risk stratification of patients at high risk for sudden cardiac death is possible and may allow identification for an aggressive approach or interventional trials.

Adult↗
PubMed1990

Internal cardioverter defibrillator: component failure.

Sudden death occurred in a patient with congestive cardiomyopathy, sustained ventricular tachycardia refractory to amiodarone, and an automatic internal cardioverter defibrillator. Interrogation of the AICD at the time of death was indicative of malfunction. Postmortem analysis documented component failure involving a voltage regulating transistor resulting in prolonged charge times.

Cardiomyopathy, Dilated↗
PubMed1984

[Incidence of ventricular arrhythmia relative to the QT interval in spontaneous intracranial hemorrhages].

A prospective study was done in 54 patients with acute spontaneous intracranial haemorrhage, 27 of them with subarachnoid bleeding and 27 with primary intracerebral haemorrhage. The frequency of ventricular arrhythmias was registered by continuous long-term ECG and the incidence of QT prolongation by daily standard ECG registration. Prolongation of frequency-corrected QT-interval (QTc) developed in 9 patients with subarachnoid haemorrhage and in 10 with intracerebral haemorrhage. For assessment of time-relation between QT-interval and ventricular arrhythmias the results of corresponding long-term ECG and standard ECG were used and two groups were defined: group A (149 tapes) = QTc less than or equal to 450 ms, group B (43 tapes) = QTc greater than 450 ms. In group B singular frequent ventricular extrasystoles, couplets and non-persistent ventricular tachycardias occurred more frequently though not significantly so. Persistent ventricular tachycardias occurred significantly more frequently in group B (14% vs. 1%, P less than 0.01). In three tapes of group B, all of them with QTc prolongation of more than 550 ms persistent ventricular tachycardias with typical "torsade de pointes " morphology were seen. The results show that QTc prolongation of more than 450 ms occurs in a third and significant ventricular arrhythmia in nearly half of patients with spontaneous intracranial haemorrhage. Persistent ventricular tachycardias occur almost only in cases of QTc-prolongation. Pronounced QTc prolongation of more than 550 ms is rare. However, it can give rise to torsade de pointes and ventricular fibrillation.

Adult↗
PubMed1984

Recurrent torsade de pointes type ventricular tachycardia in intracranial hemorrhage.

Two out of 72 cases of intracranial hemorrhage-induced polymorphous ventricular tachycardia with typical Torsade de Pointes morphology are presented. Both patients had marked QTc prolongation more than 550 ms. In one patient (QTc: 669 ms) Torsade de Pointes degenerated into fatal ventricular fibrillation. Even though polymorphous Torsade de Pointes type ventricular tachycardia is rare during the clinical course of intracranial hemorrhage, attention should be given to the QT interval. QTc prolongation more than 550 ms may carry a high risk of Torsade de Pointes type ventricular tachycardia and ventricular fibrillation.

Adult↗
PubMed1982

Complications after combination of chemotherapy and radiation for malignant brain tumours.

The combination of chemotherapy and irradiation for the treatment of malignant intracerebral tumours is increasing, and survival times longer than those after monotherapy are reported. The suitability of simultaneous radio-chemotherapy using BCNU-Bleomycin, a regimen in which has been followed 38 patients of this hospital (up to 31 December 1981) is critically discussed. Statistics of 30 patients with treatment ended by 31 December 1980 and case histories of two patients with fatal complications, aspergillosis in the one and necrotizing colitis in the other, are presented. The value of the various agents used for chemotherapy is discussed with respect to the survival rates and observed side effects in all the patients. The use of Bleomycin is questioned.

Adult↗
PubMed1981

Malignant gliomas - glioblastoma multiforme and astrocytoma III-IV with extracranial metastases. Report of two cases.

The authors describe two rate cases of extraneural metastases of glioblastoma multiforme and of astrocytoma III-IV, but with different distribution routes. In the first case - astrocytoma III-IV - via the lymphatic system, with metastases in the cervical lymph nodes; in the second case-glioblastoma-via the blood system, with metastases in the sternum and vertebrae. Survival times were 18 months in the astrocytoma case (operation plus irradiation), and 6 months in the glioblastoma case (operation, irradiation, and chemotherapy). The discussion deals with the possible paths of the metastases, the connection between metastatic spread and survival time (in the longer surviving patient the metastases were discovered together with the recurrence), and problems in deciding the individual therapy.

Adult↗