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Biomedical subjects

J Beier

Publications and source records attributed to J Beier.

At least 19 recordsLinked to original sources
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↗
PubMed1996

[3-D visualization of thoracic tumors from MR images].

AIM: In cooperation with the thoracic surgery department 3-D visualizations of tumors were generated to support the surgeons in preoperative planning. As opposed to 3-D reconstructions of CT data, those representations based on MRI images remain an exception. In this paper different methods of three dimensional visualization of lung tumors are presented and compared to each other. DESIGN: These methods are 1. contour based surface models, 2. threshold based surface models and 3. rendered scenes of segmented volume data with transparent, color-coded display. RESULTS: Combinations of all three methods in one single image are possible as well with the software we developed. Furthermore, cut planes through the original data can be integrated into the 3-D scene. The segmentation of anatomical objects is performed either manually or automatically with various procedures. CONCLUSIONS: Adequate possibilities of manipulation and archiving allow a fast handling and processing even of large data sets. The calculated volumes of the anatomical objects can be used for quantitative studies. Arbitrary views of the three dimensional reconstructions can be generated within a few seconds. Even animation can easily be calculated and displayed with 30 frames/second.

Adult↗
PubMed1996

[clinical application of multiplanar and 3D reconstruction of spiral CT in diagnosis of acetabulum fractures].

This review describes recent visualizations of computed tomography for the diagnosis of acetabular fractures. The techniques of conventional and helical-CT for the imaging of the acetabulum are compared. Furthermore, the different methods of multiplaner and three-dimensional reconstructions e.g. shaded surface display, maximum intensity projection, and volume rendering are presented. Figures of each method are demonstrated and the diagnostic potential of multiplanar and three-dimensional imaging for fractures of the pelvis is discussed.

Acetabulum↗
PubMed1996

[3-dimensional post-myelographic CT reconstruction in diagnosis and therapy planning of spinal dysraphism].

Dysrhaphia is often associated with severe osseous aberrations of the spine such as, for example scoliosis, hemivertebra, and synostosis. With the advanced possibilities of the post-processing of CT-data (segmentation, three-dimensional reconstruction), post-myelo-CT is an excellent method for the evaluation of osseous structures and the myelon in preoperative planning.

Adolescent↗
PubMed1995

Thrombospondin-related adhesive protein (TRAP) of Plasmodium falciparum: expression during sporozoite ontogeny and binding to human hepatocytes.

Plasmodium sporozoites collected from oocysts, haemocoel and salivary glands of the mosquito show profound differences in their biological properties such as motility, ability to induce protective immune response and infectivity for vertebrate host cells. Sporozoites from salivary glands are much more infectious than those from oocysts and haemocoel. Differential expression of proteins, such as the circumsporozoite (CS) protein and the thrombospondin-related adhesive protein (TRAP), implicated in sporozoite recognition and entry into hepatocytes may account for the development of infectivity during ontogeny. We have carried out a series of experiments to: (i) analyse the expression and localization of TRAP in P.falciparum sporozoites during development in the mosquito; and (ii) elucidate the biochemical and adhesive properties of recombinant TRAP. Our data indicate that TRAP is not expressed in oocysts, whereas variable amounts of CS protein are found in this parasite developmental stage. Hemocoel sporozoites display the distinct phenotypes TRAP- CS protein+ and TRAP+ CS protein+ at a frequency of 98.5 and 1.5% respectively. Salivary gland sporozoites are all TRAP+ CS protein+. We also provide experimental evidence showing that recombinant TRAP binds to the basolateral cell membrane of hepatocytes in the Disse's space and that sulfated glycoconjugates function as TRAP ligands on human hepatocytes.

Amino Acid Sequence↗
PubMed1995

[The correction for motion and visualization of subtraction angiographic data from the spiral CT].

Conventional image subtraction of CT sequences is hampered by extended motion artifacts. In this paper a motion correction procedure for the subtraction of images from two time-separate CT investigations is introduced. Native images are obtained in the first CT sequence, and a contrast medium examination is imaged in the second. The aim of image subtraction is sole presentation of the contrast medium. In contrast to conventional digital subtraction angiography (DSA), CT angiography rules out the possibility of direct image subtraction due to occurrence of extended motion artifacts in the time-shifted images. Such shortcomings can now be corrected by means of a new registration method developed for determination of local displacement vectors between the two images. This motion pattern is used to compute a new synthetic mask of maximum congruence with the contrast medium image. The resulting three-dimensional data record is presented by means of a special-purpose hardware enabling fast rotations and cut planes. New diagnostic possibilities can be achieved such as the creation of views that are not obtainable with conventional modalities and the assessment of calcified vessels.

Angiography, Digital Subtraction↗
PubMed1993

Determinants for hospitalization from an emergency mental health service.

There has been limited systematic study of determinants of acute psychiatric hospitalization of children and adolescents. This study reviewed the records of children and adolescents who received emergency mental health services in one New Jersey county during 6 months of 1990 (N = 226). Using a structured form to abstract data, information was obtained on demographics, precipitating problems, past mental health services, substance use, family problems, and disposition. While suicidal behavior was not a predictor of acute hospitalization, the interaction of assaultive and suicidal behavior was predictive. Other contributory factors identified in the multivariate analysis included: child's substance use, family member's substance use, and initial emergency screening site. Recognition of present utilization patterns will facilitate the development of intensive community-based options for those with acute mental health problems.

Adolescent↗
PubMed1993

[Benign metastatic leiomyoma of the lung].

The authors report on the case of a woman of 41 years of age presenting with asymptomatic multiple circular foci in the lung that were primarily suspected of being malignomas. Diagnosis of benign metastasising leiomyomas was confirmed for bilateral multiple circular foci suspected of lung metastasising originating from an unknown tumour of the lung. This diagnosis was achieved by open biopsy. The seemingly contradictory diagnosis of a benign but metastasising tumour is characteristic of a rare disease pattern that, however, is well documented in the literature. The course of the disease is compared with the data given in the literature.

Adult↗
PubMed1986

[Experiences with a modified nephrostomy instrument kit in ultrasound-guided kidney fistulization].

During a period of 24 months, ultrasound-guided percutaneous nephrostomies were performed in 51 patients in the Hospital at Köln-Merheim. The procedure was carried out with a modified nephrostomy instrument manufactured by Angiomed, Ettlingen, according to our own design. The procedure was successful in 49 patients. In one case it had to be abandoned because of lack of patient co-operation. In one patient a pyonephrosis was found and the patient was treated surgically.

Humans↗
PubMed1986

Hemodynamic response to LBNP following 2 hours HDT (-6 degrees).

Central hemodynamics have been determined during stepwise decreasing LBP in head-down tilt (HDT) of -6 degrees. Measurements were performed on eight healthy volunteers using right heart catheterization. During LBNP, pressures in the right atrium, pulmonary artery, and pulmonary capillary (preload) decreased in parallel with the increase of negative pressure applied to the lower part of the body. Similarly, stroke volume and cardiac output decreased with increasing negative pressure. Heart rate moderately increased (30%) as well as total peripheral resistance. The left ventricular function curve was shifted downward and to the left during LBNP indicating hypovolemia with no evidence of decreased contractility. Cardiac dimensions determined by echocardiography changed in a similar way as those obtained by invasive measurements. There was a very close correlation between stroke volume determined by thermodilution and by echocardiography. Plasma norepinephrine and dopamine tended to increase at the end of LBNP. Echocardiography proved a useful and reliable approach to hemodynamic measurement during LBNP and is recommended for analysis of hemodynamic parameters during zero G and Gz simulation.

Adult↗
PubMed1984

Central hemodynamics during zero gravity simulated by head-down bedrest.

Central hemodynamics during head-down tilt of -6 degrees lasting for 2 h were studied using catheterization of the pulmonary artery. M-mode echocardiography was performed simultaneously. Significant increases occurred for pressures in the right atrium, pulmonary artery in pulmonary wedge position, and for pulmonary vascular resistance. Cardiac and stroke volume index, heart rate, mean arterial pressure, and total systemic resistance remained constant throughout the exposure time. Constancy was also observed for echocardiographic measures of cardiac dimensions. It is concluded that head-down tilt leads to an increase of preload without any evidence of disturbed left ventricular function. No distinct time course of hemodynamic variables could be seen. Echocardiography proved a useful method to study cardiovascular adaptations during head-down tilting.

Adaptation, Physiological↗
PubMed1983

[Functional late results following peripheral replantation].

To obtain comparable ratings of late results after replantations a plan of examination is presented, including sensibility, function of tendons, degree of decrease in total hand function, integration of the replanted finger into hand function, subjective judgement of the result by the injured person, and persistent pain. Examination of 84 finger replantations showed the following results: 20% very good, 45% good, 27% satisfactory, and 10% poor.

Amputation, Traumatic↗
PubMed1979

Avian malaria in African black-footed penguins.

Ten captive-reared African black-footed penguins (Spheniscus demersus) from a large outdoor colony were monitored for avian malaria, using several diagnostic tests. One treatment regimen was evaluated. Thin smear blood evaluation enabled detection of seven parasitemias involving Plasmodium relictum and Plasmodium elongatum in the penguins. Leukocytosis (relative lymphocytosis) was characteristic of infected birds. Parasitemia was detected as early as 21 days prior to onset of clinical signs (depression, anorexia, regurgitation, pale mucous membranes, and respiratory distress). The single bird that died had clinical signs only a few hours prior to its death. Treatment consisted of 0.03 mg of primaquine phosphate base/kg body weight, administered orally once daily for 3 days. Oral chloroquine phosphate therapy, given simultaneously, was administered in an initial loading dose of 10 mg of chloroquine phosphate base/kg body weight, followed by doses of 5 mg/kg at 6, 18 and 24 hours after the initial chloroquine dose. This treatment regimen prevented mortality and cleared parasites from the blood. Recurrences of malaria occurred in two birds that had received this treatment.

Animals↗