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Biomedical subjects

Ulrich Busch

Publications and source records attributed to Ulrich Busch.

6 recordsLinked to original sources
PubMed2006

Occasional single beat regurgitation observed with the medtronic advantage bileaflet heart valve.

BACKGROUND: The purpose of this clinical study was to obtain further evidence of the underlying mechanism causing the echocardiographically detected phenomenon of single beat regurgitation in a new bileaflet heart valve. As part of a prospective multicenter trial at our institution, 63 patients received the Advantage bileaflet mechanical heart valve (Medtronic, Minneapolis, Minnesota) in aortic position. During routine follow-up performed at discharge and annually after the operation, intermittent moderate transvalvular regurgitation was detected by echocardiography in 5 patients. METHODS: Fluoroscopy of leaflet motion (n = 4), invasive blood pressure measurements in the ascending aorta (n = 3) and digital phonocardiography (n = 5) was obtained in the patients showing an intermittent regurgitation during echocardiography. RESULTS: Valve thrombosis, sutures, or pannus ingrowth impairing valve closure was not detected. Fluoroscopy of leaflet motion showed intermittent incomplete closure of either one of the two leaflets in the same prosthesis. This could be correlated with a distinct diastolic blood pressure drop in the same cardiac cycle. Digital phonocardiography showed pathologic closure sounds in those cycles in which echocardiographically the intermittent regurgitation was observed. CONCLUSIONS: Some patients with the Medtronic Advantage prosthesis in the aortic position show an intermittent inability of complete valve closure that leads to a single beat transvalvular regurgitation. As thrombotic or other material that might cause a disturbance of leaflet motion could not be detected, and the patients seem not to be exposed to any risk except for some chronic regurgitant volume, we decided not to replace the prostheses.

Aortic Valve Insufficiency↗
PubMed2005

Distortion of genetically modified organism quantification in processed foods: influence of particle size compositions and heat-induced DNA degradation.

Milling fractions from conventional and transgenic corn were prepared at laboratory scale and used to study the influence of sample composition and heat-induced DNA degradation on the relative quantification of genetically modified organisms (GMO) in food products. Particle size distributions of the obtained fractions (coarse grits, regular grits, meal, and flour) were characterized using a laser diffraction system. The application of two DNA isolation protocols revealed a strong correlation between the degree of comminution of the milling fractions and the DNA yield in the extracts. Mixtures of milling fractions from conventional and transgenic material (1%) were prepared and analyzed via real-time polymerase chain reaction. Accurate quantification of the adjusted GMO content was only possible in mixtures containing conventional and transgenic material in the form of analogous milling fractions, whereas mixtures of fractions exhibiting different particle size distributions delivered significantly over- and underestimated GMO contents depending on their compositions. The process of heat-induced nucleic acid degradation was followed by applying two established quantitative assays showing differences between the lengths of the recombinant and reference target sequences (A, deltal(A) = -25 bp; B, deltal(B) = +16 bp; values related to the amplicon length of the reference gene). Data obtained by the application of method A resulted in underestimated recoveries of GMO contents in the samples of heat-treated products, reflecting the favored degradation of the longer target sequence used for the detection of the transgene. In contrast, data yielded by the application of method B resulted in increasingly overestimated recoveries of GMO contents. The results show how commonly used food technological processes may lead to distortions in the results of quantitative GMO analyses.

DNA, Plant↗
PubMed2005

Population spectrum of ACADM genotypes correlated to biochemical phenotypes in newborn screening for medium-chain acyl-CoA dehydrogenase deficiency.

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most frequent inherited defect of fatty acid oxidation, with a significant morbidity and mortality in undiagnosed patients. Adverse outcomes can effectively be prevented by avoiding metabolic stress and following simple dietary measures. Therefore, prospective newborn screening (NBS) is being proposed for this condition. However, technical validation of MCADD population screening and assessment of its overall benefit require broadening of the as-yet-scarce knowledge of the MCADD genetic heterogeneity unraveled by NBS and its phenotypic consequences. Here, we describe the entire spectrum of sequence variations occurring in newborns with MCADD in the population of Bavaria, Germany, in relation to the biochemical phenotype. Among 524,287 newborns, we identified 62 cases of MCADD, indicating a birth incidence of 1 in 8,456. In all of the 57 newborns available for analysis, two alterations within the MCADD gene (ACADM) were identified. The most prevalent alteration c.985A>G (Lys329Glu) occurred in 27 (47%) newborns in the homozygous and in 18 (32%) in the heterozygous state (63% of defective alleles). The mild folding variant c.199T>C (Tyr67His) was identified in nine individuals, six of them being compound heterozygous with c.985A>G (Lys329Glu). Neither of the prevalent alterations were found in the remaining nine newborns. A total of 18 sequence variations were identified; 13 of them were novel: eight missense mutations, one nonsense mutation, two splice variants, and two small deletions. The remaining five were previously reported in MCADD patients. The ACADM heterogeneity uncovered was larger as anticipated from previous c.985A>G (Lys329Glu) carrier screening data. In addition, we show that MCADD appears to occur as frequently in Turkish newborns as in the native German population. Our data validate that biochemical NBS for MCADD is a highly specific procedure for disease detection, with the identification of a significant share of milder biochemical phenotypes, such as c.199T>C (Tyr67His). These show statistically lower acylcarnitine markers, allowing us to distinguish subgroups within the spectrum of ACADM sequence variations that correlate to biochemical MCADD disease expression. Our data might provide technical and medical guidance for decision making in the worldwide efforts to introduce MCADD population screening.

Acyl-CoA Dehydrogenase↗
PubMed1978

ACOUSTIC CHANGES IN NORMALLY FUNCTIONING MITRAL VALVE PROSTHESES: ECHO-PHONOCARDIOGRAPHIC OBSERVATIONS.

This study confirms previous findings of variability in the intensity of the closing click (CC) as a consequence of premature valve closure. Such alterations have been described as a normal phenomenon in several prosthetic valve models. Combined echo-phonocardiography is of particular value in evaluating prosthetic valve function in patients with unusual and confusing auscultatory changes.

Journal Article↗
PubMed1978

IDENTIFICATION OF LARGE LEFT ATRIAL THROMBUS BY CROSS-SECTIONAL AND M-MODE ECHOCARDIOGRAPHY.

In addition to a typical pattern indicative of mitral stenosis, the M-mode echo-cardiogram of a patient with mitral valve disease revealed a broad band of dense echoes within an enlarged left atrial cavity that was suggestive of an intraatrial thrombus. Subsequent cross-sectional echocardiography demonstrated a globular cluster of echoes inside the left atrial cavity, thus corroborating our interpretation of the M-mode recording. When open mitral commissurotomy was performed, a large, partially calcified thrombus was found protruding from the posterior wall and left atrial appendage into the atrial cavity. Postoperative M-mode and cross-sectional echocardiography did not show the previously noted abnormal echoes within the left atrium.

Journal Article↗