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Biomedical subjects

Helge Hebestreit

Publications and source records attributed to Helge Hebestreit.

13 recordsLinked to original sources
PubMed2006

Central nervous system borreliosis mimicking a pontine tumour.

In childhood, facial nerve palsy and headache are typical symptoms of second and third stage neuroborreliosis. While focal demyelination is occasionally observed on MRI scans, the appearance of a tumorous lesion is extremely rare. The case of a 10-year-old girl with neuroborreliosis mimicking a space-occupying lesion in the brainstem, without any previously recognized manifestations of borreliosis, is reported.

Anti-Bacterial Agents↗
PubMed2005

Role of CD95-mediated adipocyte loss in autoimmune lipodystrophy.

CONTEXT: Lipodystrophies are rare disorders characterized by the selective loss of adipose tissue. Metabolic complications increase in severity with the extent of fat loss. In some forms of acquired lipodystrophy, the loss of fat is suggested to be a result of autoimmune destruction of adipocytes. Here, the pathogenic mechanism is still poorly understood. OBJECTIVE: We have analyzed sc adipose tissue from a 5-yr-old girl with ongoing fat loss by immunohistochemistry. Using cultured human preadipocytes and adipocytes, we elucidated a possible mechanism leading to adipocyte loss in this patient. RESULTS: Analysis of adipose tissue samples of the patient with acquired lipodystrophy obtained from skin areas affected by panniculitis suggested that loss of adipocytes was mediated by CD95-induced apoptosis. Regression of adipose tissue was accompanied by lymphohistiocytic infiltration/inflammation and increased serum levels of inflammatory cytokines interferon-gamma and TNF-alpha. In vitro studies with human adipocytes demonstrated that interferon-gamma and TNF-alpha are able to up-regulate CD95 expression and enhance CD95-death-inducing signaling complex formation resulting in a robust sensitization for CD95-mediated apoptosis. CONCLUSION: We have identified here a possible mechanism responsible for the loss of adipocytes by apoptosis in autoimmune lipodystrophy.

Adipocytes↗
PubMed2005

Legionella waltersii--a novel cause of pneumonia?

UNLABELLED: A 5-y-old girl was admitted to our hospital with fever, cough, respiratory distress and rapidly increasing oxygen requirements. A chest radiograph showed bilateral central infiltrates. PCR was performed with pharyngeal washings and revealed Legionella DNA, while no genetic materials of other pathogens such as respiratory viruses, Mycoplasma and Chlamydia were detected. The clinical condition improved gradually after administration of steroids and therapy with clarithromycin. Further sequencing of Legionella DNA led to the identification of Legionella waltersii. This Legionella species has never been described as a human pathogen before. CONCLUSION: For the first time, L. waltersii was identified as a cause of severe pneumonia. Since L. waltersii is not detected by routine laboratory tests, it may be speculated that these bacteria, like other Legionella species, are underestimated as a probable cause of community-acquired pneumonia.

Anti-Bacterial Agents↗
PubMed2005

Oxygen uptake kinetics are slowed in cystic fibrosis.

PURPOSE: There are conflicting reports on the kinetics of oxygen uptake at the onset of exercise in patients with cystic fibrosis (CF). The objective of the present study was, therefore, to compare oxygen uptake (VO(2) kinetics in patients with CF with those of healthy controls (CON). METHODS: Eighteen CF patients (FEV1 37-98% predicted) and 15 CON aged 10-33 yr completed two to four transitions from low-intensity cycling (stage 1, 20 W) to cycling at 1.3-1.4 W.kg(-1) body weight (stage 2). There was no difference between groups in heart rate at stages 1 and 2 or in relative exercise intensity, as expressed as percent VO(2peak) or percentage of ventilatory threshold. However, oxygen saturation (SpO(2)) was lower in the patients with CF during both stages. VO(2) data were interpolated second by second, time-aligned, and averaged. Monoexponential equations were used to describe phase II VO(2) responses. RESULTS: Although there were no differences between CF and CON in amplitude (10.9 +/- 1.8 vs 10.2 +/- 1.6 mL O2.W(-1)) of phase II VO(2) response, the time constant tau was significantly prolonged in CF compared with CON (36.8 +/- 13.6 vs 26.4 +/- 9.1 s). When tau was adjusted for the effects of FEV1 or SpO(2) during submaximal exercise, the difference between CF patients and controls disappeared. CONCLUSION: VO(2) kinetics are slowed in CF, which may, in part, be attributed to an impairment of oxygen delivery.

Adolescent↗
PubMed2004

Assessment of human pulmonary function using oxygen-enhanced T(1) imaging in patients with cystic fibrosis.

Indirect qualitative MRI of pulmonary function is feasible using the paramagnetic effects of oxygen physically dissolved in blood. In this study, a more quantitative oxygen-enhanced pulmonary function test based on the slope of a plot of R(1) vs. oxygen concentration-the oxygen transfer function (OTF)-was developed and tested in a pool of five healthy volunteers and five patients with cystic fibrosis (CF). The lung T(1) relaxation rate, R(1), under normoxic conditions (room air, 21% O(2)), and the response to various hyperoxic conditions (40%-100% O(2)) were studied. Lung T(1) in healthy volunteers showed a relatively homogeneous distribution while they breathed room air, and a homogeneous decrease under hyperoxic conditions. Lung T(1) in CF patients showed an inhomogeneous distribution while they breathed room air, and the observed lung T(1) decrease under hyperoxia depended on the actual state of the diseased lung tissue. In the selected group of CF patients, areas with reduced OTF also showed reduced perfusion, as confirmed by qualitative contrast-enhanced MR pulmonary perfusion imaging. The results demonstrate that this completely noninvasive oxygen-enhanced pulmonary function test has potential for clinical applications in the serial diagnosis of lung diseases such as CF. .

Adolescent↗
PubMed2004

Exercise testing and training in German CF centers.

Physical exercise is increasingly recognized as a valuable diagnostic and therapeutic modality for patients with cystic fibrosis (CF). We sought to characterize the use of exercise testing and training as well as the attitude toward both issues through a national survey. A questionnaire was sent to 107 specialized CF centers (caring for a total of 5,231 patients) and 7 inpatient rehabilitation institutions. Answers were available from 62 specialized centers caring for 3,580 patients and from 4 rehabilitation centers with 520 treatment episodes per year. Sixty percent of specialized centers performed some sort of exercise testing at an average frequency of 1 in 2.3 years for patients aged 8 and above. However, protocols and indication criteria were often unstandardized or not specified at all. Equipment availability was no major problem, and the majority of tests were conducted by a physician alone. Nineteen centers had adopted exercise testing as part of their diagnostic routine. Two thirds of caregivers advised their patients to engage in physical activity, but failed to discuss specific modalities and potential hazards. Nevertheless, physical exercise was viewed as "extremely important" or "very important" by 87%. In a rehabilitation setting, an exercise test was conducted 1.1 times per patient stay, and a training program offered in 100% of cases. In conclusion, standardized exercise testing and training programs appear to be underused in German CF centers, despite a high degree of interest in the topic. Supplementary material for this article can be found on the Pediatric Pulmonology website (http//www.interscience.wiley.com/jpages/8755-6863/suppmat).

Adult↗
PubMed2004

Exercise testing in children -- what works, what doesn't, and where to go?

Exercise testing is a valuable tool in the assessment of healthy children and those with a chronic disease. However, especially for testing small children modified equipment is required. The choice of the exercise protocol and the outcome variables depends mainly on the reason for conducting the test. Future developments in pediatric exercise testing will focus on testing protocols designed to accommodate the specific biology and behavior of children. A further focus will be on the development of norms based on appropriate scaling techniques.

Child↗
PubMed2003

Fibrosing mediastinitis with superior vena cava obstruction as the initial presentation of Langerhans' cell histiocytosis in a young child.

We present a 2-year-old girl with an unusual presentation of Langerhans' cell histiocytosis (LCH). Five months prior to admission to our hospital, she received IV steroids for bronchial obstruction. On admission, clinical signs of SVC obstruction were evident and a mediastinal mass was evident on the chest radiograph and MRI. Biopsy revealed fibrosing mediastinitis. Five months later, osteolysis was present on a skull radiograph. Surgical biopsy of the skull lesion revealed LCH. This case is unique because it demonstrates a rare initial manifestation of LCH that has not been previously reported. Furthermore, the primary, solitary mediastinal manifestation without calcifications was histologically interpreted as fibrosing mediastinitis, and the final diagnosis of LCH was only made after identifying the skull lesion.

Child, Preschool↗
PubMed2003

Quantitative perfusion mapping of the human lung using 1H spin labeling.

PURPOSE: To evaluate the feasibility and reproducibility of a noninvasive, rapid and quantitative pulmonary perfusion mapping method using a two-compartment tissue model in combination with a (1)H spin labeling technique. MATERIALS AND METHODS: Ten healthy volunteers and three patients with cystic fibrosis (CF) were examined on a 1.5-T whole-body scanner. Global and selective lung T(1) maps based on an inversion recovery Snapshot FLASH technique were acquired from each subject with breath-holds at end-expiration. For comparison, corresponding Gd-DTPA-enhanced (1)H MR perfusion images were also obtained from each CF patient. RESULTS: Quantitative perfusion maps were calculated from the global and selective T(1) maps. The measured perfusion rates of the upper right lung in volunteers ranged from 400 to 600 mL/100 g/minute. The method showed a high intra-study reproducibility and low relative errors. In CF-patients, perfusion defects detected using Gd-DTPA-enhanced MR imaging were also detected using the spin labeling method. The perfusion rates of diseased lung tissues were less than 200 mL/100 g/minute. CONCLUSION: Noninvasive, robust and quantitative (1)H MR mapping of pulmonary perfusion was successfully performed using a rapid lung T(1) mapping in combination with spin labeling within the imaging slice. The proposed method has the potential to provide both important qualitative functional information and quantitative pulmonary perfusion rates in various lung diseases at various stages without the need of contrast agents.

Adult↗
PubMed2003

Head size and motor performance in children born prematurely.

PURPOSE: The objective of this study was to determine the relationship between head circumference (HC) and motor performance in 6- to 12-yr-old children born prematurely (PRE: birthweight < or = 1500 g, gestational age < or = 32 wk) and in children born at term (CON). METHODS: Thirty-three PRE and 21 CON without an apparent neurological deficit participated in this study. HC was measured on the day of testing and was rated as small HC (SHC, HC more than 1 SD below the 50th percentile of reference data) or as normal HC (NHC). Subjects were examined by an experienced neuropediatrician, and whole-body coordination was assessed by the Körper-Koordinationstest für Kinder (KTK). Peak exercise performance was determined by a Wingate test and an incremental cycling test to volitional fatigue. Net oxygen cost of cycling was measured during four different tasks lasting 5-7 min each. Subjects pedaled at an intensity corresponding to 30% and 60% of peak oxygen uptake ([OV0312]O(2peak)) at a cadence of 36 and 76 rpm, respectively. RESULTS: Prematures with SHC showed no statistically significant difference in their neurological examination and whole-body coordination compared with prematures with NHC. Wingate test performance and [OV0312]O(2peak) relative to body mass were similar among SHC, NHC, and CON. In SHC, but not in NHC and CON, net oxygen cost of cycling increased significantly (P < 0.05) when cadence was increased from 36 to 76 rpm. CONCLUSION: At the age of 6-12 yr, SHC have a higher oxygen cost of cycling in exercise tasks requiring high velocity, which might be explained-at least in part-by an impaired neural control of intra- and intermuscular coordination.

Biomechanical Phenomena↗
PubMed2002

Temperature-related overestimation of energy expenditure, based on heart-rate monitoring in obese boys.

An equation has been developed to reduce the error in predicting energy expenditure (EE) from heart rate (HR) monitoring, by correcting for climate-related HR increases. To evaluate the effects of such a correction in a "real life" situation, a group of 9- to 14-year-old obese boys [mean (SD) 36.6 (3.3)% body fat; n=14] was monitored for 6 days during the summertime. An activity interview was taken daily. During times of outdoor activities, measurements of HR were corrected for the influence of ambient temperature ( T) using the aforementioned equation. Time spent outdoors was 196.7 (21.1) min/day at a T of 17-34 degrees C. Temperature correction reduced the time spent at HR>140 beats/min and >160 beats/min by 20-25% during outdoor activity. Estimated outdoor EE corrected for the influence of temperature was 2.46 (2.37) MJ; the uncorrected value was 2.68 (2.45) MJ. The respective values for the waking hours and over 24 h were 7.34 (2.77) MJ versus 7.55 (2.81) MJ and 10.83 (2.72) MJ versus 11.05 (2.77) MJ, respectively. The excessive HR measured in a warm summer climate could explain 8.8 (3.5)% of EE during outdoor activities, which resulted in a 2.9 (2.7)% overestimate of EE during daily waking hours and a 1.9 (1.8)% overestimate of the total 24-h EE. Thus, the influence of temperature on HR may, at least in part, explain the previously reported overestimate of EE calculated using the HR/oxygen consumption relationship versus that calculated using the doubly labelled water method. We recommend correcting HR for the influence of climate in studies using HR profiles to determine outdoor physical activity levels and/or EE during summertime. However, when total daily EE or waking hours EE is assessed, even in subjects who are engaging in long intervals of outdoor play, the temperature correction required is minimal.

Adolescent↗
PubMed2002

Magnetization transfer short inversion time inversion recovery enhanced 1H MRI of the human lung.

The unique characteristics of the human lung arising from low proton density and multiple air-tissue interfaces of the alveoli cause difficulty in 1H lung magnetic resonance imaging. In addition, the dominating signal from sources such as the thoracic muscle and subcutaneous fat hampers the visualization of the lung parenchyma. In this contribution, an efficient tissue suppression technique is presented which allows one to significantly enhance lung parenchyma visibility. A short inversion time inversion recovery (STIR) experiment combined with a magnetization transfer (MT) experiment was used for magnetization preparation in order to suppress the signal from muscle. A half-Fourier single-shot turbo spin-echo sequence was used as acquisition module. This approach was used to perform lung anatomical imaging in eight healthy human subjects and five patients with cystic fibrosis. The results obtained demonstrate that with MT-STIR approach high quality human lung images can be obtained and that this approach has the potential for the evaluation of lung pathologies.

Adult↗