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Biomedical subjects

R Becker

Publications and source records attributed to R Becker.

At least 19 recordsLinked to original sources
PubMed2006

Early diagnosis of conjoined twins by real-time three-dimensional ultrasound--case report and review of the literature.

In 1:50 000 to 1:100 000 births, conjoined twins occur, caused by incomplete division of the embryonic disc more than 13 days after fertilisation. We present a case of cephalothoracopagus janiceps, a very rare form of conjoined twins, which was diagnosed at 13 weeks of gestation. Three-dimensional and colour Doppler ultrasound enabled precise prenatal visualisation of the fusion of the foetal head and chest up to the umbilicus. We could demonstrate the presence of two foetal hearts connected by an arterio-arterial shunt as well as two pairs of upper and lower extremities. After the clear 3-D presentation of the anomaly, making the poor prognosis visible, the mother decided to have the pregnancy terminated. Autopsy confirmed the prenatal diagnosis.

Adult↗
PubMed2006

Silent microemboli related to diagnostic cerebral angiography: a matter of operator's experience and patient's disease.

INTRODUCTION: The aim of the present investigation was to elucidate in a large consecutive patient cohort whether the level of training has an effect on the number of microemboli detected by diffusion-weighted imaging (DWI) and which additional risk factors can be identified. METHODS: A total of 107 consecutive patients in whom a diagnostic cerebral angiography had been performed were prospectively investigated with DWI; 51 angiographies were performed by experienced neuroradiologists, 56 by neuroradiologists in training. RESULTS: In 12 patients (11.1%), a total of 17 new lesions without any clinically overt neurological symptoms were identified. Of these, 12 patients, 11 (91.7%) with 16 lesions were investigated by junior neuroradiologists. In 11 of 12 patients with DWI abnormalities (91.7%), risk factors could be identified (atherosclerotic vessel wall disease, vasculitis, hypercoagulable states). Experienced neuroradiologists performed 21 of 48 angiographies (43.8%) on patients with the above-mentioned risk factors, whereas junior neuroradiologists performed 27 angiographies in this subgroup (46.2%). The rate of diffusion abnormalities in patients with risk factors was 11/48 (22.9%) - considerably higher than in patients without risk factors (1/59; 1.7%). CONCLUSION: The level of experience and the nature of the underlying disease are predictors of the occurrence of cerebral ischemic events following neuroangiography. Alternative diagnostic modalities should be employed in patients who are investigated for diseases with the highest risk of angiographic complications (i.e., vasculitis, and arteriosclerotic vessel wall disease). If diagnostic angiography remains necessary in these patients, the highest level of practitioner training is necessary to ensure good patient outcome.

Adolescent↗
PubMed2006

Detailed screening for fetal anomalies and cardiac defects at the 11-13-week scan.

OBJECTIVE: To assess the diagnostic efficacy of the first-trimester anomaly scan including first-trimester fetal echocardiography as a screening procedure in a 'medium-risk' population. METHODS: In a prospective study, we evaluated 3094 consecutive fetuses with a crown-rump length (CRL) of 45-84 mm and gestational age between 11 + 0 and 13 + 6 weeks, using transabdominal and transvaginal ultrasonography. The majority of patients were referred without prior abnormal scan or increased nuchal translucency (NT) thickness, the median maternal age was, however, 35 (range, 15-46) years, and 53.8% of the mothers (1580/2936) were 35 years or older. This was therefore a self-selected population reflecting an increased percentage of older mothers opting for prenatal diagnosis. The follow-up rate was 92.7% (3117/3363). RESULTS: The prevalence of major abnormalities in 3094 fetuses was 2.8% (86/3094). The detection rate of major anomalies at the 11 + 0 to 13 + 6-week scan was 83.7% (72/86), 51.9% (14/27) for NT < 2.5 mm and 98.3% (58/59) for NT >or= 2.5 mm. The prevalence of major congenital heart defects (CHD) was 1.2% (38/3094). The detection rate of major CHD at the 11 to 13 + 6-week scan was 84.2% (32/38), 37.5% (3/8) for NT < 2.5 mm and 96.7% (29/30) for NT >or= 2.5 mm. CONCLUSION: The overall detection rate of fetal anomalies including fetal cardiac defects following a specialist scan at 11 + 0 to 13 + 6 weeks' gestation is about 84% and is increased when NT >or= 2.5 mm. This extends the possibilities of a first-trimester scan beyond risk assessment for fetal chromosomal defects. In experienced hands with adequate equipment, the majority of severe malformations as well as major CHD may be detected at the end of the first trimester, which offers parents the option of deciding early in pregnancy how to deal with fetuses affected by genetic or structural abnormalities without pressure of time.

Adolescent↗
PubMed2006

[Efficiency potential in the pacemaker/implantable cardioverter defibrillator outpatient clinic].

The aim of the present study was to elucidate whether the duration of a technical follow-up (FU) of a pacemaker (PM)/implantable cardioverter defibrillator (ICD) has an impact on cost-effectiveness in the outpatient clinic. We determined the time required for a complete FU of devices from three different manufacturers. In 130 patients (70 VVI/DDD-PM, 60 VVI/DDD-ICD) with either a PM (Phylos, Chorum/Talent, Kappa, EnPulse) or an ICD (Belos, Alto or GEM) the time was recorded for a complete FU including determination of lead impedance, sensing and pacing threshold. The time for activation of individual menue buttons was excluded. On the basis of time required for FU, cost-units (CU) were calculated for 2000 FU/year and for a presumed device longevity (PM 7 years, ICD 5 years). For VVI-PM, the duration of FU was almost identical for devices from different manufacturers (105+/-11 s to 125+/-8 s; p=n.s.). However, analysis of DDD-PM revealed marked differences (140+/-25 s vs 282+/-23 s, p<0.05). Time for FU of ICDs varied between 108+/-5 s and 207+/-21 s (p<0.05) in VVI-ICDs and between 129+/-8 ms and 225+/-23 s (p<0.05) in DDD-ICDs. The total savings could be 55 000 CU in VVI- and 53 333 CU in DDD-ICDs. For full automatic DDD-pacemakers (EnPulse) time for FU could be reduced to 58+/-3 s (p<0.05). Differences in FU times were caused by problems with telemetry, delay during booting of the programmer, interrogation at the beginning and at the end of FU and for sensing tests. Improving not only programmers and devices but also test automaticity could significantly increase cost-efficiency in the outpatient clinic.

Ambulatory Care↗
PubMed2006

[Landolt C and snellen e acuity: differences in strabismus amblyopia?].

BACKGROUND: Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since optotypes are evaluated on individuals with good visual acuity and without eye disorders, differences in the lower visual acuity range cannot be excluded. In this study, visual acuity measured with the Snellen E was compared to the Landolt C acuity. PATIENTS AND METHODS: 100 patients (age 8 - 90 years, median 60.5 years) with various eye disorders, among them 39 with amblyopia due to strabismus, and 13 healthy volunteers were tested. Charts with the Snellen E and the Landolt C (Precision Vision) which mimic the ETDRS charts were used to assess visual acuity. Three out of 5 optotypes per line had to be correctly identified, while wrong answers were monitored. In the group of patients, the eyes with the lower visual acuity, and the right eyes of the healthy subjects, were evaluated. RESULTS: Differences between Landolt C acuity (LR) and Snellen E acuity (SE) were small. The mean decimal values for LR and SE were 0.25 and 0.29 in the entire group and 0.14 and 0.16 for the eyes with strabismus amblyopia. The mean difference between LR and SE was 0.55 lines in the entire group and 0.55 lines for the eyes with strabismus amblyopia, with higher values of SE in both groups. The results of the other groups were similar with only small differences between LR and SE. CONCLUSION: Using the charts described, there was only a slight overestimation of visual acuity by the Snellen E compared to the Landolt C, even in strabismus amblyopia. Small differences in the lower visual acuity range have to be considered.

Adolescent↗
PubMed2006

[Influence of body position on ocular cycloposition in patients without binocular vision].

PURPOSE: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. Previous studies have shown no influence of body position on cycloposition in healthy subjects with normal binocular vision. METHODS: 10 subjects (median value of age 44.2 years) without binocular vision due to an organic eye disease or to strabismus were examined using three-dimensional video-oculography (3D-VOG). This non-invasive method can record changes in the position of both eyes simultaneously in the x-, y- and z-axes. The cycloposition of the eyes was recorded first in a seated position with both eyes open (test 1), then in a supine position with the right eye closed (test 2), then in a supine position with occlusion of both eyes (test 3), and then in a supine position with both eyes open (test 4). In each of these 4 situations, the eyes were recorded for 1 minute. Cyclovergence was calculated as the difference between the right and the left eye positions. RESULTS: The range of cycloposition of the right and left eye in all 4 tests was very small. 95 % confidence intervals for cycloposition of the right and left eyes and for cyclovergence: cycloposition right eye/cycloposition left eye/cyclovergence: 0.72;0.76/- 0.07;0.01/0.71;0.79 (test 1), 0.23;0.29/0.19;0.33/- 0.81;- 0.63 (test 2), - 0.92;0.7/- 0.51;- 0.37/- 0.79;- 0.45 (test 3), 0.14;0.52/- 0.07;0.31/0.59;0.21 (test 4). There was no statistically significant difference of the cycloposition between the 4 test situations. CONCLUSIONS: The cycloposition of the eyes does not significantly change between seated and supine positions of the body, either in subjects with, or without binocular vision. This means for refractive surgery that a correction of astigmatism, to be performed in the supine position of the patient, can be based on a measurement of the axis of astigmatism obtained in the seated position.

Adult↗
PubMed2006

[Systemic bias in the photographic assessment of the first purkinje image].

BACKGROUND: The growing popularity of digital imaging leads to an increasing number of photos transferred by parents via E-mail to an ophthalmologist, showing a child with a displacement of corneal reflections. This must not necessarily lead to the diagnosis of manifest strabismus. MATERIALS AND METHODS: The displacement of the first Purkinje image is demonstrated by moving the flash of a digital camera sideways from the objective. Photographs were taken at a distance of 0.6 m while the healthy test subject was looking into the camera. Flashlight was displaced gradually up to 20 cm to the left side of the objective. The resulting displacement of the corneal reflections was measured after transferring the photos to a computer. RESULTS: Displacement of the source of light by 10 cm resulted in a displacement of the first Purkinje image of about 1 mm, i. e., about 0.1 mm per degree. CONCLUSIONS: Displacement of corneal reflection was 0.1 mm per degree. Asymmetry of corneal reflections is twice as much, since the corneal reflections are displaced in the same direction on both eyes. Lateral displacement of the flash from the objective of the camera by 2.5 cm results in an asymmetry of 0.5 mm, thus suggesting a squint angle of 6 degrees. Vice versa, a real strabismus can be masked. This bias can be avoided by using the camera with the flash above the objective in relation to the patient's interpupillar axis. Nevertheless, it is impossible to diagnose or to exclude a microstrabismus by this method itself, because an angle kappa, if it is different on both eyes, can also mimic or mask a manifest strabismus.

Artifacts↗
PubMed2006

Electrophysiological proof of diffusion-weighted imaging-derived depiction of the deep-seated pyramidal tract in human.

In the living human brain the pyramidal tract (PT) can be displayed with magnetic resonance diffusion-weighted imaging (DWI). Although this imaging technique is already being used for planning and performing neurosurgical procedures in the PT vicinity, there is a lack of verification of DWI accuracy in other areas outside the directly subcortical PT parts. Before definitive electrode placement into the subthalamic nucleus (STN) in patients with Parkinson disease (PD) for chronic stimulation, the stimulation effect on PD symptoms and the side-effects, namely PT activation at the level of the internal capsule (IC), are electrophysiologically tested. To analyze DWI accuracy by matching the stereotactic coordinates of the electrophysiologically proven IC position with these of the DWI-derived IC display, DWI was added to the routine MRI work-up in the stereotactic frame prior to functional surgery in 6 patients. In all of the 10 displayed fiber tracts, concordant findings for imaging and macrostimulation were made. The authors proved for the first time that DWI correctly depicts the deep seated, principle motor pathways in the living human brain. Due to methodical limitations of this study the accuracy of the proven IC display is limited to 3 mm which has proven to be sufficient for the planning and performance of neurosurgical procedures in the vicinity of large fiber tracts.

Adult↗
PubMed2005

Regional differences in the dynamics of refractoriness in intact and hypertrophied in situ canine hearts.

OBJECTIVES: Functional re-entry is thought to represent the predominant mechanism underlying ventricular arrhythmias. Functional conduction block may be caused by regional dispersion of refractoriness (ERP). Dispersion of ERP may not be evident at baseline, but may occur with sudden changes in heart rate, as ventricular arrhythmias are commonly induced by short-long-short cycles. METHODS: We examined the dynamics of local ERPs at two left ventricular (LV) sites in dogs with either no structural heart disease or biventricular hypertrophy (BVH). ERPs were determined at each of four bipoles of two adjacent needle electrodes in the LV apex and the lateral wall. The stimulation protocol included two different basic cycle lengths, one or two longer cycles after a train of 6 or 5 shorter cycles, and one shorter cycle after a train of 6 longer cycles. RESULTS: In normal dogs, a significant apicolateral ERP gradient was only evident with the longer basic cycle length. One shorter cycle was sufficient to dissolve that gradient. One longer cycle was enough to create a regional ERP gradient. Dynamic regional gradients occurred because the apex responded more markedly and more readily to abrupt changes in cycle length. BVH led to an increase in ERP at both LV sites and to an aggravation of regional ERP gradients. CONCLUSIONS: Dynamic ERP behavior seems to depend on topography and underlying pathology. Abrupt changes in heart rate might induce dynamic refractory gradients between various regions of the normal heart, but also between adjacent regions inhomogenously affected by hypertrophy.

Animals↗
PubMed2005

[Molecular basis of primary electrical heart diseases].

The last decade has seen rapid progress in our understanding of the molecular basis of arrhythmias, particularly concerning hereditary arrhythmia syndromes. This has led to significant improvement regarding differentiation, risk stratification and therapy in these patients and their families. However, there is mounting evidence that the knowledge obtained by studying these rare monogenic disorders will also enable us to dissect the molecular mechanisms underlying polygenetic and multi-factorial arrhythmias that are by far more common in clinical practice. The goal of this review is to give a brief overview of current knowledge on the molecular basis of primary electrical heart diseases. A focus is on the long QT syndrome.

Action Potentials↗
PubMed2004

[Dissociated near reflex and accommodative convergence excess].

We report on an 8-year-old boy whose near reflex could be elicited exclusively when the left eye was fixing (LF) but not when the right eye was fixing (RF). With RE +1.25/-1.25/169 degrees and LE +1.0/-0.75/24 degrees, the visual acuity was 1.0 OU at 5 m and RE 0.5, LE 1.0 at 0.3 m improving to 1.0 OU by a near addition of 3.0 D. Stereopsis was 100 degrees (Titmus test). The prism and cover test revealed an esophoria of 4 degrees at 5 m. At 3 m there was an esophoria of 6 degrees (RF) and an esotropia of 28 degrees (LF), compensating to an esophoria of 3 degrees (RF/LF) with a near addition of 3.0 D. Accommodation and the pupillary near reaction (OU) were hardly elicitable during RF. During LF, retinoscopy revealed an accommodation of 8 D (OU) and the pupils constricted normally. Correction by bifocal glasses yielded orthotropia with random dot stereopsis at near.

Accommodation, Ocular↗
PubMed2004

Is 'virtual histology' the next step after the 'virtual autopsy'? Magnetic resonance microscopy in forensic medicine.

AIM: The study aimed to validate magnetic resonance microscopy (MRM) studies of forensic tissue specimens (skin samples with electric injury patterns) against the results from routine histology. METHODS AND RESULTS: Computed tomography and magnetic resonance imaging are fast becoming important tools in clinical and forensic pathology. This study is the first forensic application of MRM to the analysis of electric injury patterns in human skin. Three-dimensional high-resolution MRM images of fixed skin specimens provided a complete 3D view of the damaged tissues at the site of an electric injury as well as in neighboring tissues, consistent with histologic findings. The image intensity of the dermal layer in T2-weighted MRM images was reduced in the central zone due to carbonization or coagulation necrosis and increased in the intermediate zone because of dermal edema. A subjacent blood vessel with an intravascular occlusion supports the hypothesis that current traveled through the vascular system before arcing to ground. CONCLUSION: High-resolution imaging offers a noninvasive alternative to conventional histology in forensic wound analysis and can be used to perform 3D virtual histology.

Adult↗
PubMed2004

[Presentation of visual acuity in ophthalmological publications].

BACKGROUND: Visual acuity is one of the most important functions of the visual system. Visual acuity is the basis of many decisions in clinical practice. The assessment of visual acuity is clearly defined (norm EN ISO 8596). In this study, the presentation of results of visual acuity assessments in the ophthalmological literature was analysed. MATERIALS AND METHODS: All the issues of the journals "Klinische Monatsblatter fur Augenheilkunde" and "Der Ophthalmologe" of the years 2002 and 2003 were reviewed especially concerning the procedure of visual acuity assessment, the scaling in the lower visual acuity range, axis scaling and the calculation of mean values of visual acuity. RESULTS: In total, 550 publications were reviewed. Of these papers, 207 contained at least one visual acuity value and 42 papers presented detailed data concerning either the change of visual acuity over a certain time interval, or mean values, or using charts. A linear scale was used in 9 of 28 papers with presentation of visual acuity measurements in a chart. Of 32 publications with visual acuity measurements less than 0.2, only 2 used a logarithmic scale in the lower visual acuity range, while in 14 papers, scaling was rather rough or not numeric (e. g., counting fingers). Sixteen papers used the units "finger counting" or "hand movements" to describe low visual acuities. The way of calculating mean values remained obscure in 36 papers. CONCLUSIONS: Regarding a correct assessment of visual acuity and the effect of therapy, the fundamental guidelines of visual acuity assessment and its correct presentation should be considered.

Humans↗
PubMed2004

[Quality indicators for ambulatory health education programme for overweight and obese children and adolescents].

BACKGROUND: In Germany, 9 to 12 % of all children between five and seven years of age have been shown to be overweight at school entry; 2.5 to 3.5 % of them are obese. Therapeutic intervention for obese children and adolescents is considered to be indicated especially in cases where an increased body mass index (BMI) is accompanied by a disease the effective treatment of which requires weight loss. Furthermore, the child and its family must be willing to actively change their habits. OBJECTIVE: A multitude of health care providers have begun to offer multidisciplinary group programme for prevention and treatment of obesity to affected individuals and their families. The Medical Service of the Statutory Health Insurance (MDK) has therefore developed a list of quality and assessment criteria for such programme. METHODS: A systematic search for information in international and national publications was performed using standard methodology of evidence-based medicine. Data were extracted and assessed according to pre-defined criteria taking into consideration previously published clinical guidelines and opinions of expert panels. RESULTS: Nearly all available studies were of low internal validity and mostly of poor methodological quality. Therefore, no binding recommendations for the design of health education programme for overweight and obese children and adolescents can be given. Potentially successful intervention should combine the following 4 modules: nutrition, physical activity, change of eating habits, physical activity habits and life style using methods of behavioural therapy, and involvement of parents. Such combinations may have the potential to reduce or stabilise the BMI at least during a defined period of time. In younger children, the beneficial effect will be more pronounced if the parents are actively involved. CONCLUSION: Up to now informative studies have not reliably shown that the effect of ambulatory health education programmes for overweight and obese children and adolescents and their parents may last for more than one or two years. Therefore, a controlled clinical trial determining the long-term effectiveness of such programme is imperative. The decision whether a defined programmes should be included in such a study could be taken on the basis of the quality indicators and assessment criteria described here.

Ambulatory Care↗
PubMed2004

Dependency of the metabolic effect of sc-injected human regular insulin on intra-abdominal fat in patients with type 2 diabetes.

Ten patients with type 2 diabetes were enrolled in an isoglycemic glucose clamp study to determine the impact of intra-abdominal fat, subcutaneous abdominal fat and total abdominal fat on the metabolic effect of a single bolus (0.2 IU/kg) of sc-injected human regular insulin. The maximum metabolic effect associated highly and negatively with intra-abdominal fat (r = - 0.72, p < 0.02) and with the homeostasis model assessment insulin resistance score (HOMA, r = - 0.71, p < 0.03). Likewise, the total metabolic effect of sc-injected insulin correlated strongly and negatively with intra-abdominal fat (r = - 0.77, p < 0.01), HOMA (r = - 0.74, p < 0.02) and HbA (1c) (r = - 0.70, p < 0.03). Stepwise multiple regression analyses showed that the highest metabolic effect was only significantly predicted by intra-abdominal fat, indicating a high negative correlation with the maximum effect (beta = - 0.72) whereas time to maximum metabolic effect showed a strong (beta = 0.72) and positive correlation with HOMA. In combination with the HOMA, it is intra-abdominal fat, and not subcutaneous abdominal fat, which explains 50 - 75 % of the variability of the effect of sc human regular insulin in patients with type 2 diabetes.

Abdomen↗
PubMed2004

Use of preoperative assessment of positionally induced cyclotorsion: a video-oculographic study.

PURPOSE: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. The method of binocular three dimensional infrared video-oculography (3D-VOG) was used to determine a possible influence of body position on cyclotorsion. METHODS: 38 eyes (19 healthy subjects, median value of age 25.5) with normal binocular vision were examined using 3D-VOG. This method records ocular motions and positions of both eyes simultaneously in the x, y, and z axis. Cycloposition of the eyes was recorded first in a seated position (both eyes open, test 1), then in a supine position (right eye closed, test 2), occlusion of both eyes (test 3), both eyes open (test 4). Cyclovergence was calculated as the difference between the right and the left eye positions. RESULTS: The range of cyclotorsion of the right and left eye in all four tests was between 1.13 degrees excyclotorsion and 0.34 degrees incyclotorsion. There was no statistically significant difference of the median values for torsion for the four test situations. Concerning the influence of body position on cyclotorsion, a statistically significant difference between the different test positions and settings did not exist. Median values for right/left torsion/cyclovergence were: 0.17/0.04/0.02 (test 1), -0.31/-0.71/-0.16 (test 2), -1.09/-0.60/0.82 (test 3), 0.28/0.28/-0.82 (test 4). CONCLUSIONS: Cyclotorsion does not significantly change between seated and supine position in subjects with normal binocular vision and stable fixation. In these subjects, an erroneous refractive surgery due to incorrect measurement of the axis of astigmatism in the seated position and performing the refractive surgery in the supine position, is very unlikely.

Adult↗