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H Oswald

Publications and source records attributed to H Oswald.

At least 37 records · Page 2Linked to original sources
PubMed1996

The construction of the World Wide Web-accessible myocardial two-dimensional gel electrophoresis protein database "HEART-2DPAGE": a practical approach.

The construction of the two-dimensional electrophoresis (2-DE) gel protein database "HEART-2DPAGE" for human heart proteins, accessible via the World Wide Web (WWW), is described. This database provides the opportunity to retrieve descriptive information interactively by mouse clicking on a protein spot within a 2-DE gel image or to retrieve the position of a protein if its protein name or a search expression is given. The realization of searching for proteins, the creation of clickable spots, marked by crosses or textual information, and interactive viewing opportunities are discussed from a software-oriented point of view. The database takes into account that some human heart proteins are chamber specific. Several Common Gateway Interface (CGI) scripts are described and some practical experience is discussed.

Computer Communication Networks↗
PubMed1996

Accuracy and precision of angiographic volumetry methods for left and right ventricle.

We imaged and quantified 60 ventricle casts (30 LV, 30 RV) to evaluate the accuracy and reliability of angiographic ventricle volumetry. We analyzed the seven biplane methods most frequently used in clinical routine: Arcilla, Arvidsson, Dodge, Ferlinz, Simpson (LV + RV) and Wynne. The ventricle contours were defined by (1) manual drawing on the computer screen, (2) manual drawing using a graphical tablet and (3) automatic contour detection. A high inter-class variation in volume accuracy between the different methods was observed (S.D. = 12.7 ml). The volume methods for the LV (mean differences MDLV: [-2.2, +8.5] ml, average MDLV = 1.8 ml) are more accurate than for the RV (MDRV: [-11.4, +33.1] ml, average MDRV = 12.1 ml). The intrinsic error is about the same for all approaches and is very high: average S.D. = 20 ml, RMS = 185 ml. Manual contour definition results in a volume over-estimation (average MDman = +32.8 ml, r = 0.731) compared with automatic contour detection (average MDauto = +6.2 ml, r = 0.810). LV hypertrophy results in a volume under-estimation of the LV (MDLV = -7 ml) and an over-estimation of the RV (MDRV = +6 ml). RV hypertrophy leads to the opposite effect. It was shown that ventricle volumetry and the calculation of derived parameters (ejection fraction) is extremely case dependent and can only be an estimate of the actual value.

Angiography↗
PubMed1995

Changes of fluid-dynamic parameters in peripheral stenoses with transcutaneous interventions.

UNLABELLED: Peripheral vessels provide a useful in vivo haemodynamic model allowing evaluation of local intravascular fluid dynamics. Velocity measurements using a 0.018 inch Doppler-tipped angioplasty guidewire, quantitative angiography and laboratory data were gathered from 45 patients with a total of 48 percutaneous transluminal laser assisted angioplasties (PTLA) in the superficial femoral, in the iliac, in the popliteal artery and in the peroneal artery. From these data, blood flow, whole blood viscosity, Reynold's numbers, Womersley numbers and shear stress were calculated, evaluated as to their changes post PTLA and correlated with clinical improvement at early follow-up. The clinical result was quantified as categorial improvement according to the American Heart Association guidelines. The primary angiographic results of angioplasty were satisfactory in all patients. Clinically 17/45 patients showed a marked, 6/45 a moderate, 18/45 a minimal, and 4/45 no improvement. The mean values of maximal peak velocity at stenosis decreased from 235 +/- 28 cms-1 to 84 +/- 8 cms-1 after PTLA (P < 0.01). The minimal intrastenotic cross section increased from 7.7 +/- 0.9 to 21.9 +/- 1.6 mm2 (P < 0.01). Mean trans-stenotic flow increased after intervention by about 50% (P < 0.01) and improved further by 135% after administration of adenosine triphosphosphate i.a. (P < 0.01). Reynold's numbers were elevated intrastenotically (1285 +/- 198) pre-intervention as compared to values proximal (564 +/- 81) and distal (449 +/- 66) to the stenosis and were reduced significantly (P < 0.05) at stenosis by PTLA, whereas values proximally and distally increased significantly (P < 0.01) post PTLA (proximal 829 +/- 84, intra 773 +/- 107, distal 676 +/- 98). Shear stress, reflecting mechanical interaction between flow and vessel wall, was elevated at stenosis pre-intervention to 44 +/- 8.9 Pa and reduced at post-stenoric vessel sites to 2.4 +/- 0.5 Pa. PTLA caused a decrease in stenosis to 6.3 +/- 1 Pa (P < 0.01) and an increase distally to 4.6 +/- 1 Pa (P < 0.01). Whereas in single stenoses removal of the obstruction was associated with a significant (P < 0.05) increase in trans-stenotic flow and shear stress distally, there was only auenuated increase in trans-stenotic flow in multiple lesions despite an angiographically good PTLA result. Shear stress distally remained low in those patients. Velocities and Reynold's numbers were lower in these vessels even pre PTLA. Residual flow, Reynold's number and minimal cross-section pre-intervention correlated significantly with clinical outcome. Pooling cases with no or minimal, as opposed to those with marked or moderate improvement, 81% of patients were correctly classified using the Reynold's numbers pre- and post-PTLA. CONCLUSION: Peak velocity monitoring is feasible and safe during angioplasty. Velocity provides clinically relevant physiological information in addition to angiography. Combining quantitative angiography, velocity measurements and laboratory data allow the calculation of blood flow, Reynold's numbers and shear stress, thereby providing complex fluid dynamic information. Thus the evaluation of haemo-dynamics in single and multiple obstructions before and after intervention is improved. Fluid dynamic parameters pre-and post-PTLA are significantly correlated with clinical short-term result.

Adult↗
PubMed1994

[Communication and integration of medical documents for the teleconference use. An outcome of the BERMED project].

The collaboration between physicians is supported in the BERMED project by implementing the remote access to distributed patient data and the realisation of computer-based medical conferencing. This requires the integration of the multimedia data in form of a meta-patient record for our medical application systems. These applications are supported by a distributed information management promoting access to different information systems, imaging modalities and digital archival storage systems. The features of image processing are concerned with quantification, segmentation and 3-D-visualisation to obtain additional information. This paper gives an overview of the actual state of the teleconferencing system in radiology.

Computer Communication Networks↗
PubMed1994

Clinical results of coronary excimer laser angioplasty: report from the European Coronary Excimer Laser Angioplasty Registry.

From January 1991 to January 1993 the clinical and angiographic data of 470 patients were included in the European Coronary Excimer Laser Angioplasty Registry. Symptoms were CCS class 3 in 23% and CCS class 4 in 14.7%; unstable angina was present in 14.7% and 6.6% of patients had acute myocardial infarction. Of 477 treated lesions, 60% were type B2, and 19% type C. The lesion was located in the LAD in 61%, in the LCX in 16%, in the RCA in 20%, in a protected left main stem in 1.3% and in a saphenous vein graft in 2.5%, respectively. Failure of laser angioplasty occurred in 56 (12%) interventions. By multivariate analysis failure was associated with the intention to treat long segmental lesions (risk ratio (RR) 3.6, confidence interval (CI) 2.9 to 4.4; P = 0.0005), segments with severe prestenotic tortuosity (RR 3.5, CI 2.4 to 4.6; P = 0.02) and total occlusions (RR 2.1; CI 1.4 to 2.8; P = 0.05). Complications included vasospasm (13.4%), dissection (14.7%), flow limiting dissection (4%), reclosure (7.8%), and perforation (1.9%). Myocardial infarction occurred in 2.1%, CABG was requested in 1.9%, and the mortality was 1.5%. Procedural success was achieved in 89%. Individual morphological criteria for a reduced procedural success were the presence of a thrombus (RR 6.4; CI 5.0 to 7.7; P = 0.007) and vessel calcification (RR 2.6; CI 1.9 to 3.2; P = 0.005). Procedural success was slightly lower in type C lesions (86%) than in type B2 (88%) type B1 (95%), and type A lesions (92%), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

[A new methodologic approach for determining right ventricular volumes from transesophageal echocardiography].

In order to develop a concept of right ventricular volume estimation accounting for variance in positioning of the transesophageal transducer, non-linear scale transformations of suitable measurements of areas and perimeters were used in a new modeling-approach. This type of modeling supposes self-similarity of ventricular dimensions, a mathematical concept generalizing the notion of proportionality. In a study using right ventricular casts, we were able to demonstrate the geometry of right ventricles complies with these assumptions. The resulting multivariate power law volume estimators were developed by non-linear data fitting by learning-analyses based upon angiographic reference volumes and two areas derived from non-orthogonal sections using a monoplane transducer in a first series of studies, and two orthogonal areas with corresponding perimeters using a biplane device in a second series. Correction factors for systolic and diastolic volumes were applied. By prospective test-analyses angiographic and TEE-derived volumes were compared to evaluate our volume estimator and good agreement was found. Trend was evaluated by correlation amounts to r = 0.95 (n = 22) in series 1 with monoplane transducer, and r = 0.9 (n = 20) in series 2 with biplane transducer. This approach is of use in monitoring right ventricular function in cases with unsuitable transthoracical windows, e.g., in cardiac surgery postoperatively.

Adult↗
PubMed1993

[Diagnosis of the dynamic lesion].

Rupture of atheromatous plaques, thrombosis and spastic contractions cause dynamic lesions in coronary arteries. This review focuses on the diagnostic approach to vasospastic lesions. Our current knowledge considers vasospastic angina as a--most likely--localized disease of the vascular smooth muscle, which occurs in nonatherosclerotic as well as in atherosclerotic segments. Currently the diagnosis can only be proven by functional tests under angiographical control. Since the pathophysiological mechanisms leading to vasospasm remain unclear, only empirically developed pharmacological tests are available. The use of ergonovine alkaloids is well established, the feasibility of acetylcholine is under investigation. The reproducibility regarding the course of the disease and the localization of the lesion has not yet been determined. The necessity to state the diagnosis is given by the improved prognosis of the disease under effective therapy with calcium channel blockers and nitrates.

Acetylcholine↗
PubMed1992

Sexuality and AIDS: attitudes and behaviors of adolescents in east and west Berlin.

The study which was conducted in 1990 in Berlin, Germany, compares two samples of 542 adolescents from West Berlin and 340 from East Berlin. The present investigation shows that the general trend toward sexual liberality among adolescents is continuing and that necessary processes of adolescent sexual development appear not to be influenced by the threat of AIDS. Though the level of knowledge about the threat of AIDS is, on the whole, satisfactory, this does not in itself guarantee determined and consistent AIDS-preventive behavior. Fewer than one-third of sexually-active adolescents, and even fewer than one-fourth of those in the most sexually-active group, can be described as consistent users of condoms. The attitudes of adolescents in regard to contraceptive characteristics only partly suggest a preference for condoms. When adolescents are asked directly about condoms, they additionally emphasize their effect of reducing feeling and pleasure. Adolescents with experience of sexual intercourse rate condoms more negatively than do those without such experience. However, AIDS-education efforts can make use of the fact that consistent condom-users expressed clearly more positive attitudes to condoms than did others. Although the comparison between East and West Berlin adolescents yielded differences in certain details, these differences are not of significance to AIDS-education programs which seek to increase AIDS-preventive behavior.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Coronary angiography and interventional cardiology.

The purpose of coronary arteriography is to image the pathoanatomic morphology fundamental to diagnosis and therapy. Interventional cardiology aims to eliminate the pathologic substrate as completely as possible. The interventional techniques and the assessment of their success are based on an exact geometric and, in particular, functional analysis of coronary artery stenoses. Recent progress in coronary arteriography has involved, firstly, quantification of structural and functional aspects. Secondly, the direct application of the information provided, which permits immediate diagnosis and treatment, demands real-time availability and maximum quality, especially for imaging difficult geometric conditions.

Angioplasty, Balloon, Coronary↗
PubMed1985

Measurement of flow-physiologic parameters of retinal blood circulation in type 1 and 2 diabetics before and after photocoagulation.

In seven diabetics of type 1 and seven of type 2, the flow physiologic magnitudes were measured in a retinal quadrant before and after photocoagulation. The segmental blood flow, the arterial flow velocity, and the diameters of artery and vein are smaller after photocoagulation than before. Investigations into the time course of the flow-physiologic parameters following photocoagulation show that the flow-physiologic values are stationary about 2 weeks after photocoagulation.

Adult↗
PubMed1983

[Measurement of flow physiology of the large vessels in retinal circulation in type 1 and type 2 diabetics].

Segmental blood flow, velocity, and vessel diameter were measured in 21 eyes of diabetic individuals with diabetes type 1 and 2. The results for arterial blood flow, velocity, arterial and venous vessel diameter in diabetes show significant differences from the results measured in normal individuals. These flow magnitudes, excluding arterial diameter, significantly depend on the duration time of diabetes. The retinal blood flow magnitudes alter before the marks of diabetic retinopathy are visible. There are differences between the results in diabetes type 1 and type 2 regarding dependence on the duration time of diabetes.

Adolescent↗
PubMed1976

[Problem of catheter-embolism following subclavian puncture].

The catheterisation into the subclavian vein is important in the intensive therapy and for the prolonged parenteral nutrition. Numerous complications are described. In 300 catheterisations into the subclavian vein we observed 3 damages of catheters. The causes damages of catheters are investigated with the help of experiments. Recommendations to the prevention of the damage and the embolism of the subclavian catheters are given.

Adult↗