Biomedical subjects

A Stadler

Publications and source records attributed to A Stadler.

At least 19 recordsLinked to original sources

PubMed2007

[Radiologic diagnosis of lung tuberculosis].

The radiologic knowledge of tuberculosis-associated lung disease is an essential tool in the clinical diagnosis of tuberculosis. Chest radiography is the primary imaging method, but the importance of CT is still increasing, as CT is more sensitive in the detection of cavitation, of hilar and mediastinal lymphadenopathie, of endobronchial spread and of complications in the course of the disease. In addition, CT has been proven as a valuable technique in the assessment of tuberculosis activity, especially in patients where M. tuberculosis has not been detected in the sputum or in patients with multidrug-resistant tuberculosis. Depending on the immune status of the patient, the morphologic spectrum of tuberculosis is quite variable. Early diagnosis of tuberculosis is essential to prevent further spread of the disease.

Adult↗

PubMed2006

[T1 maps and O2-enhanced MRT of the diseased lung. Emphysema, fibrosis, mucoviscidosis].

PURPOSE: Gas exchange is the primary function of the lung and the transport of oxygen plays a key role in pulmonary physiology and pathophysiology. MATERIALS AND METHODS: Molecular oxygen is weakly paramagnetic, so that an increase in oxygen concentration results in shortening T1 relaxation time and thus increasing signal intensity in T1 weighted images. The calculation of parameter maps may allow deeper insights into relaxation mechanisms. T1 maps based on a snapshot FLASH sequence obtained during the inhalation of various oxygen concentrations allow the creation of an oxygen transfer function, providing a measurement of local oxygen transfer. T1 weighted single shot TSE sequences demonstrate the signal changing effects during inhalation of pure oxygen. RESULTS: The average of the mean T1 values over the entire lung during inspiration was 1,199+/-117 ms, the average of these values during expiration was 1,333+/-167 ms. T1 maps of patients with emphysema and lung fibrosis show fundamentally different values and respiratory dependence compared to healthy individuals. Oxygen enhanced MR has the potential to assess reduced diffusion capacity and decreased transport of oxygen in patients with emphysema and cystic fibrosis. DISCUSSION: Results published in the literature indicate that T1 mapping and oxygen enhanced MR are promising new methods in functional imaging of the lung.

Administration, Inhalation↗

PubMed2006

[PTA and stent placement distal to the superficial femoral artery].

Although angioplasty and stent applications in the iliac vessels and the superficial femoral artery have become routine procedures, their usefulness for the treatment of lesions of the popliteal artery and the lower leg arteries is still under discussion. For the popliteal artery, limitations are mainly due to the high mechanical stress in this area, causing high traction forces. Moreover, beyond the occlusive atherosclerotic changes, specific pathological entities such as aneurysms, emboli, entrapment syndromes, and cystic adventitial disease have to be differentiated. There is hope that the development of innovative stent designs with high flexibility might overcome the limitations. For lesions of the lower leg arteries treatment with percutaneous transluminal angioplasty (PTA) has become the method of choice. However, stent designs as used for cardiac interventions have been adapted for their application below the knee, and first encouraging results may help to justify their broad use in the future. Regarding PTA, innovative equipment and techniques for the treatment of arterial lesions below the knee include dedicated, long, and very flexible balloons, cutting balloon cryoplasty, and laser angioplasty. Regarding stents, bare metal stents, stents with passive or active coatings, and bioabsorbable stents have all been successfully used.

Angioplasty, Balloon↗

PubMed2004

[Fractures of the atlantoaxial complex in the elderly: assessment of radiological spectrum of fractures and factors influencing imaging diagnosis].

OBJECTIVE: To describe patterns of atlantoaxial fractures in a population of consecutive elderly patients, including assessment of type, distribution and associated clinical and radiological findings, and to analyze any influence of the causative trauma mechanism on the individual fracture pattern. MATERIALS AND METHODS: The distribution and type of 123 atlantoaxial fractures in 95 subjects older than 65 years (range: 65 - 102; mean age: 79 years) were retrospectively assessed. For each subject, trauma mechanism and clinical and neurological status were recorded at admission. Initial imaging studies of the cervical spine were reviewed. Preexistent degenerative changes were assessed and the atlantoaxial fractures classified. Data were evaluated for the frequency of different types of fractures of C1 and C2 and for accompanying fractures of cervical vertebrae or the occipital condyles, respectively. RESULTS: The majority of patients with injuries of the atlantoaxial complex had fractures of C2 (90 of 95, 95 %). A large proportion of these patients (67 of 90, 74 %) had odontoid fractures. An isolated fracture of C1 was present in only 5 (5 %) patients. Associated fractures of the occipital condyles or other cervical vertebrae were rare (10 of 95, 11 %). The main trauma mechanism for atlantoaxial injuries was a fall (56 of 95, 59 %). Elderly patients injured in motor vehicle accidents were more likely to have isolated fractures of C2 and Type III fractures of the odontoid (p < 0.02). CONCLUSION: In elderly patients, fractures of the atlantoaxial complex are mainly caused by falls and almost always involve C2. The trauma mechanism influences the fracture pattern.

Accidental Falls↗

PubMed2002

[The limping child. Differential radiologic diagnosis of acute gait disorder in childhood and adolescence].

Limping is a common and often challenging problem in children and adolescents. A limp is defined as asymetric deviation from a normal gait pattern. A systematic approach is necessary to determine the cause of the limp, so the radiologist should combine a thorough history, clinical information and pertinent radiologic testing. The possible differential diagnosis is extensive and includes many pathologies of the lower extremity and spine like trauma, infection, neoplasia, furthermore inflammatory, developmental and congenital disorders. In cases with knee or tight pain, an underlying hip condition should be considered. The childs age can narrow the possible differential diagnoses, because certain entities are age-related. Despite this wide bandwidth of entities, potential catastrophic causes like septic arthritis and malignant disease should be excluded first. Plain radiographs are often diagnostic. The choice of further imaging modalities like ultrasonography, magnetic resonance imaging, computed tomography and bone scan should be guided by the history and clinical findings.

Adolescent↗

PubMed2002

[Digital radiography: from storage phosphor plates to direct detector systems].

All three currently commercially available systems for digital radiography of the chest such as the selenium drum, storage phosphor plates and the flat panel direct detector systems provide an excellent image quality that is at least equivalent or superior to that of conventional film. Reasons for that are the continuously improved detective or dose efficiency of the detector systems and an improved image processing. The new direct detector systems have the largest potential for dose reduction while storage phosphor and selenium radiographs are usually obtained with a dose comparable to that of a 400 speed system. Improved image processing algorithms allow for the production of digital images that are adapted to the conventional image characteristics within the lung regions combined with an increased transparency of the high absorption areas such as the retrocardial and retrodiaphragmatic regions.

Equipment Design↗

PubMed2001

Treatment of lead poisoning with an immobilized chelator comparison with conventional therapy.

Lead poisoning is a global public health problem. In pregnant women it may result in developmental delays of the fetus, in children it my produce learning disability. Available chelators are nephrotoxic when eliminated as lead-chelator complexes. For safe removal of lead from the body we developed a "Lead-Hemopurifier" (L-HP), a device with an immobilized chelator. In vitro, applied to lead solutions, this device reduced the lead concentration. Applied to dogs with lead intoxication, Lead-HP-s removed lead from the blood; this was continuously replaced by lead from the bones until the skeleton was cleared from lead deposit. Treatment of lead poisoning in dogs with Lead-HP-s compared favorably with Versenate treatment of children with lead toxicity. This report demonstrates the in vivo efficiency and safety of this new detoxfication method. Methods to induce lead poisoning in dogs and procedures to identify lead released from skeletal deposits are described.

Animals↗

PubMed2000

Videofluoroscopy of swallowing in symptomatic patients who have undergone long-term intubation.

OBJECTIVE: The aim of this study was to evaluate whether specific patterns of swallowing dysfunction occur in symptomatic patients after long-term intubation. SUBJECTS AND METHODS: Twenty-one patients (16 men, five women; mean age, 66 years) who presented with clinical signs of aspiration after long-term intubation (mean duration, 24.6 days) underwent videofluoroscopy. They were analyzed for functional abnormalities of the tongue, soft palate, epiglottis, hyoid and larynx, pharynx, and the upper esophageal sphincter. We assessed the presence or absence of aspiration, the type of aspiration (pre-, intra-, and postdeglutitive), and a spectrum of other swallowing abnormalities. RESULTS: There were 18 patients (86%) with radiologically proven aspiration. In another patient only laryngeal penetration occurred. There were 11 combinations of pre-, intra-, and postdeglutitive aspiration. Predeglutitive aspiration was predominant and present in 52% of our patients. We found functional abnormalities of the tongue in 48%, of the soft palate in 10%, of the epiglottis in 48%, of the pharynx in 71%, and of the upper esophageal sphincter in 24%. CONCLUSION: Patients who are symptomatic after undergoing long-term intubation do not develop a specific type or pattern of swallowing dysfunction or aspiration, but show a large variety of aspiration types and associated swallowing disorders. Nevertheless, videofluoroscopy has the ability to reveal complex deglutition disorders and to aid precise planning of individualized functional swallowing therapy.

Aged↗

PubMed1999

[Staging of breast carcinoma. Value of diagnostic imaging].

In women with breast cancer, staging of the tumor plays an important role and often is considered to be the most prognostic and therapeutic factor. The most widely used staging system is based on the pathologic TNM classification. In recent years conservative therapies such as preoperative chemo- or radiotherapy are used more often with limited tissue evaluation resulting in insufficient or even inaccurate staging data. Tumor size as well as nodal involvement is decisive in selecting a treatment method and assessing the response. Thus, more accurate preoperative in vivo staging is necessary. This article therefore gives an overview of the different imaging modalities (mammography, ultrasonography, magnetic resonance imaging, and nuclear medicine) used for breast cancer staging. Furthermore, results of these methods are compared critically with the pathohistologic staging.

Breast↗

PubMed1999

Prenatal immune priming in onchocerciasis-onchocerca volvulus-specific cellular responsiveness and cytokine production in newborns from infected mothers.

This study investigated the effect of maternal Onchocerca volvulus infection on humoral and cellular responsiveness in newborn children and their mothers. Onchocerca volvulus-specific IgG isotypes and IgE were significantly elevated in infected mothers and their infants. One year post partum, O. volvulus-specific IgG4 was strongly reduced in children of infected mothers, while IgG1 responses weakened only slightly. Umbilical cord mononuclear blood cells (UCBC) and peripheral blood cells (PBMC) from mothers proliferated in response to phytohaemagglutinin (PHA), concanavalin A (Con A), and the bacterial antigens streptolysin-O (SL-O) or purified protein derivative (PPD). UCBC from neonates born to O. volvulus-infected mothers responded lower (P < 0.01) to Con A (at 5 micrograms/ml), PPD (at 10 and 50 micrograms/ml) and O. volvulus-derived antigens (OvAg) (at 35 micrograms/ml), and in parallel, a diminished cellular reactivity (P < 0.01) by PBMC was observed to OvAg in mothers positive for O. volvulus. Several Th1-type (IL-2, IL-12, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha)) and Th2-type (IL-4, IL-5, IL-10, IL-13) cytokines were secreted by UCBC and PBMC in response to OvAg, bacterial SL-O and PHA. OvAg did not stimulate IL-2 and none of the mitogens or antigens induced production of IL-4 in neonates. In response to OvAg, substantially elevated (P < 0.01) amounts of IFN-gamma were produced by UCBC from newborns of O. volvulus-infected mothers. UCBC secreted low levels of IL-5 and IL-13, while higher amounts of IL-10 were found (P < 0. 01) in newborns from onchocerciasis-free mothers. In conclusion, maternal O. volvulus-infection will sensitize in utero parasite-specific cellular immune responsiveness in neonates and activate OvAg-specific production of several Th1- and Th2-type cytokines.

Adolescent↗

PubMed1999

Regulatory effects of Th1-type (IFN-gamma, IL-12) and Th2-type cytokines (IL-10, IL-13) on parasite-specific cellular responsiveness in Onchocerca volvulus-infected humans and exposed endemic controls.

The present study investigated in vitro the regulatory effects of T helper 1 (Th1)-type (interferon-gamma, IFN-gamma; interleukin-12, IL-12) and Th2-type cytokines (IL-10, IL-13) on Onchocerca volvulus-specific cellular reactivity in onchocerciasis patients, and in exposed endemic control individuals presenting no clinical and parasitological signs of disease. In both patients and controls, addition of IL-10 dose-dependently depressed O. volvulus antigen (OvAg)-specific cellular proliferation, and peripheral blood mononuclear cells (PBMC) from patients who were more sensitive to the suppressive effect of IL-10 than those from endemic controls. However, neutralization of IL-10 by specific antibody did not reverse cellular hyporesponsiveness. In contrast to the inhibitory effects of IL-10, exogenous IL-12 and IL-13 augmented PBMC proliferative responses to OvAg both in patients and controls (P<0. 01) and neutralizing of IL-12 or IL-13 significantly decreased OvAg-specific proliferation in both groups. Exogenous IFN-gamma did not activate OvAg-specific proliferative responses in patients, but anti-IFN-gamma antibodies abolished cellular reactivity to OvAg. Antibody to IL-10 increased (P<0.05) OvAg-specific production of IL-5, IL-12 and IFN-gamma, and inversely, anti-IFN-gamma enhanced IL-10 (in patients only) and IL-5 and IL-13 in both patients and controls. Neutralization of IL-12 activated OvAg-specific production of IL-10, IL-2 and IFN-gamma. In conclusion, despite of an overproduction of IL-10, which suppressed cellular reactivity in patients and control individuals, OvAg-specific cellular responses were activated in vitro by exogenous supplementation with IL-12 and IL-13, and cytokine neutralization experiments confirmed that distinct type 1 and type 2 T helper cytokines cross-regulate expression and magnitude of O. volvulus-specific cellular responsiveness in humans.

Adolescent↗

PubMed1997

The diverse expression of immunity in humans at distinct states of Onchocerca volvulus infection.

This study examined the development and persistence of immunity in humans presenting defined states of Onchocerca volvulus infection, i.e. in exposed endemic control individuals without microfilaridermia and clinical disease, in patients with patent or post-patent onchocerciasis, and in patients concurrently infected with Mansonella perstans. Onchocerca volvulus antigen (OvAg)-specific cellular reactivity was significantly diminished in microfilariae (mf)-positive patients, while the highest reactivity was measured in exposed but mf-negative endemic controls, those being free of any clinical signs of onchocercal disease. In patients who became post-patent, responses to OvAg were significantly augmented, but did not approach entirely the magnitude observed in endemic controls. In onchocerciasis patients with concurrent mansonelliasis, cellular unresponsiveness to OvAg persisted, even when mf of O. volvulus were eliminated permanently by repeated ivermectin therapy. Cells from mf-positive onchocerciasis patients produced significantly less interferon-gamma (IFN-gamma) (P < 0.01) and interleukin-5 (IL-5) (P < 0.05) in response to OvAg than those taken from endemic controls or post-patent individuals in whom IFN-gamma and IL-5 production was similarly high. In contrast, both OvAg-driven as well as spontaneous IL-10 secretion was higher in mf-positive patients than in endemic controls or post-patent cases. In all individuals examined, serological recognition of OvAg by immunoglobulins was dominated by IgG4; in mf-positive patients OvAg of 205,000-12,000 molecular weight (MW) were strongly bound. In post-patent individuals, and similarly in endemic controls. OvAg recognition by IgG4 varied from intense (with numerous antigens being recognized) to weak or absent antigen binding. Significantly elevated OvAg-specific IgG isotypes were measured in mf-positive onchocerciasis patients in comparison with endemic controls or post-patent individuals (with the exception of IgG3). IgG1, IgG2 and IgE were higher, but IgG4 was lower in endemic controls compared with post-patent onchocerciasis patients. The ratios of IgG4/IgG1 differed (P < 0.001) between endemic controls and mf-positive or post-patent onchocerciasis patients, with IgG4/IgG1 ratios of R < 3.0 being characteristic for endemic controls and post-patent O. volvulus infection. In conclusion, this cross-sectional immunoepidemiological investigation showed that distinct states of O. volvulus infection correlate with a particular cellular and humoral immune response. The mf-free condition appeared to be associated with a vigorous parasite-specific cellular reactivity and a particular cytokine production profile, while concurrent M. perstans infection depressed OvAg-specific cellular responsiveness. Antibody responses, in all likelihood, reflected the intensity and state of infection, and not the degree of acquired immunity protective against parasite aggregation.

Adolescent↗

PubMed1997

Surveillance on Salmonella in turkey flocks and processing plants.

The present investigation was carried out to investigate the occurrence and distribution of Salmonella infection on all stages of turkey production. Therefore, samples from turkey parent flocks, hatchery, meat turkey flocks, turkey feed and finally from the surveillanced flocks at different steps in processing plant were examined. Salmonella was isolated from 4 out of 6 turkey parent flocks (66.7%), but none of the examined 485 samples from the hatchery revealed positive Salmonella results. Eight out of 24 monitored meat turkey flocks were free from Salmonella during the entire rearing period (33.3%); seven flocks (29.2%) appeared to be infected with only one serovar and in another 9 flocks (37.5%) two or more different serovars were isolated during the rearing period, in some cases at the same time. In 20 out of 506 examined feed samples Salmonella was isolated (3.95%). During processing, bacteriological investigations on the presence of Salmonella were carried out on the monitored flocks at different processing steps. Cross contamination seems to be very common during processing and even in several flocks contamination appeared to have started already during transport.

Animal Feed↗

PubMed1997

Salmonella enteritidis colonization in turkey poults.

An experimental trial on the colonization of two Salmonella enteritidis strains (phage types 4 and 8) originating from meat turkey flocks, were carried out. Three-day old poults were inoculated orally with approximately 10(6) cfu/bird (one group with PT8 and the other with PT4). clinical signs were not observed in any of the groups. The total reisolation rates from cloacal swabs in birds inoculated with PT4 was higher than from birds inoculated with PT8. The inoculated strains could also be detected in contact birds. Examination of internal organs 21 days p.i. revealed higher isolation rates in the group infected with PT4 than with PT8. The results indicate that both phage types of S. enteritidis were able to colonize the intestinal tract and the internal organs of turkey poults. However, the colonization and duration of shedding differed between the two phage types. This may be due to the fact that PT8 strain used was free from the S. e. virulence plasmid 37 MDa.

Animals↗

PubMed1996