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A Lederer

Publications and source records attributed to A Lederer.

At least 19 recordsLinked to original sources
PubMed2006

[Feasibility of fetal echocardiography at 11-14 weeks scan].

PURPOSE: Sonographic diagnostics are increasingly brought forward into the first trimenon. Lately, more and more expert studies have been published on echocardiography in the context of the Nuchal Translucency (NT) screening (gestational age 11-14 weeks). The aim of this study has been to evaluate the feasibility of early echocardiography on the occasion of first trimenon screening in the context of routine operation. MATERIALS AND METHODS: From February 2003 to March 2004, an echocardiography was prospectively sought in 130 assigned, unselected pregnant women during the first trimenon screening. Three doctors with different OGUM/DEGUM (Austrian and German societies for ultrasound in medicine) qualifications at our ward tried to represent the four-chamber view (4CV) and the outflow tracts (OFT), each via B-mode and color Doppler. The study conditions were "routine", in particular they were temporally limited. In case no sufficient visual representation was achievable with the transabdominal examination, transvaginal sonography was also used. RESULTS: Via B-mode, 4CV was indicated as successful in 86/130, and OFTs in 37/130. Via color Doppler, on the other hand, it was possible to sufficiently represent 4CV in 75/130 and OFTs in 87/130. CONCLUSION: In routine screening, early heart examination is a big challenge and in many cases even with good equipment no complete diagnostic echocardiography can be achieved. The utilisation of the color Doppler is helpful particularly for the representation of the outflow tracts.

Echocardiography↗
PubMed2002

Chest sonography in the diagnosis of pulmonary embolism: a comparison with MRI angiography and ventilation perfusion scintigraphy.

AIM: To compare the diagnostic performance of chest sonography, MRI angiography and ventilation/perfusion intigraphy in pulmonary embolism (PE). METHOD: In a prospective clinical study, 55 patients (41 women, 14 men, age 23 - 91 years) with clinical signs of PE were investigated within 48 hours of the onset of symptoms. The final diagnosis was made by MRI angiography (reference method). RESULTS: PE was diagnosed in a total of 36 patients. Chest sonography revealed rounded or wedge-shaped hypoechoic lesions in 30 patients. On ventilation/perfusion (V/P) scintigraphy, 41 patients had positive V/P scans, but only 23 were of high probability. Chest ultrasound had a positive predictive value of 97 % to diagnose PE. The sensitivity, specificity, the negative predictive value and accuracy were 81 %, 84 %, 84 % and 82 %, respectively. As 18 patients had inconclusive scans, the diagnostic performance of ventilation/perfusion scintigraphy was poor. The positive predictive value, sensitivity and specificity were 58 %, 42 % and 91 %, respectively. Patients in whom PE was excluded mainly suffered from congestive heart failure, bronchopulmonary infections or pulmonary hypertension. CONCLUSION: A negative sonographic study cannot rule out PE with certainty. However, a chest sonography is of acceptable diagnostic value in patients with suspected PE and may be used as an adjunct or guide to more established methods.

Adult↗
PubMed1999

Human simulations of vocabulary learning.

The work reported here experimentally investigates a striking generalization about vocabulary acquisition: Noun learning is superior to verb learning in the earliest moments of child language development. The dominant explanation of this phenomenon in the literature invokes differing conceptual requirements for items in these lexical categories: Verbs are cognitively more complex than nouns and so their acquisition must await certain mental developments in the infant. In the present work, we investigate an alternative hypothesis; namely, that it is the information requirements of verb learning, not the conceptual requirements, that crucially determine the acquisition order. Efficient verb learning requires access to structural features of the exposure language and thus cannot take place until a scaffolding of noun knowledge enables the acquisition of clause-level syntax. More generally, we experimentally investigate the hypothesis that vocabulary acquisition takes place via an incremental constraint-satisfaction procedure that bootstraps itself into successively more sophisticated linguistic representations which, in turn, enable new kinds of vocabulary learning. If the experimental subjects were young children, it would be difficult to distinguish between this information-centered hypothesis and the conceptual change hypothesis. Therefore the experimental "learners" are adults. The items to be "acquired" in the experiments were the 24 most frequent nouns and 24 most frequent verbs from a sample of maternal speech to 18-24-month-old infants. The various experiments ask about the kinds of information that will support identification of these words as they occur in mother-to-child discourse. Both the proportion correctly identified and the type of word that is identifiable changes significantly as a function of information type. We discuss these results as consistent with the incremental construction of a highly lexicalized grammar by cognitively and pragmatically sophisticated human infants, but inconsistent with a procedure in which lexical acquisition is independent of and antecedent to syntax acquisition.

Adult↗
PubMed1993

Agenesis of the dorsal pancreas in a woman with diabetes mellitus and in both of her sons.

Complete agenesis of the dorsal pancreas has rarely been described. Complete agenesis of the dorsal pancreas in a female who developed insulin-dependent diabetes mellitus at the age of 39 years is reported. The diagnosis of agenesis of the dorsal pancreas was suspected by abdominal ultrasound and confirmed by abdominal computed tomography (CT), magnetic resonance imaging, and endoscopic retrograde pancreatography. Her exocrine pancreatic function was essentially normal. Both of the patient's sons also had agenesis of the body and tail of the pancreas verified by abdominal CT but had no evidence of diabetes mellitus. This familial occurrence of agenesis of the dorsal pancreas suggests that hereditary mechanisms may play a role in the pathogenesis of this anomaly.

Adult↗
PubMed1993

Malignant ureteral obstruction: preliminary results of treatment with metallic self-expandable stents.

Self-expandable metal stents 7 mm in diameter were percutaneously implanted into 13 ureters in 10 patients with malignant ureteral obstruction not amenable to double-J stent placement. In nine ureters, one stent was placed, and in four ureters, two overlapping stents were placed. Primary reconstitution of ureteral patency was achieved in all ureters. After 1-2 weeks, four ureters showed a urothelial reaction encroaching on the lumen of the ureter, and a double-J stent was placed coaxially. One ureter was occluded by urothelial hyperplasia 4 weeks after stent placement, and a double-J stent was therefore placed. One ureter was occluded 8 months after stent placement by distal tumor overgrowth. The other ureters showed no signs of obstruction during a follow-up of 3-14 (average, 5.8) months. Peristalsis was preserved at both ends of the stent in all ureters. The use of this stent alone or in combination with a double-J stent alleviated upper urinary tract obstruction and avoided external drainage in all patients.

Adult↗
PubMed1993

Malignant fibrous histiocytoma of the mesentery--a rare cause of abdominal pain. Case report with a review of literature.

Malignant fibrous histiocytoma (MFH) is a tumor most frequently occurring in lower and upper extremities and in retroperitoneum. This paper presents the extremely rare case of a 55-year-old male patient with a MFH of storiform pleomorphic subtype originating from the mesentery. Sonography, computed tomography as well as endoscopy and ERCP did not reveal the diagnosis. Finally the tumor was diagnosed by laparoscopy with biopsy and histological examination. Two months after diagnosis of the tumor the patient died of bronchopneumony and heart failure contracted during a generalisation of MFH.

Abdominal Pain↗
PubMed1992

[Extrinsic allergic alveolitis in CT and HR-CT].

The CT changes on conventional and high-resolution CT in 14 patients with exogenous allergic alveolitis (EAA) were analysed retrospectively. There were 8 patients with clinically subacute disease, 5 patients in a chronic stage and 1 patient with acute EAA. The appearances and their distribution were examined. Seven of the 8 patients in the subacute stage showed a ground glass pattern and multiple nodules of less than 2 mm. All patients in the chronic stage showed a combination of fine infiltrates, small nodules and irregular linear densities; distortion of the pulmonary pattern was present in 3 cases. The patient with acute EAA showed diffuse dense areas of consolidation in both lungs as well as multiple nodules and a ground glass pattern. The CT appearances of EAA correspond with the basic micropathology and, within the clinical context, permit diagnostic classification.

Adult↗
PubMed1990

[A solitary metastasis in the trapezium bone].

Carpal bone is an uncommon location for metastases, and diagnostic problems can occur when a solitary metastasis mimics acute arthritis or osteomyelitis clinically as well as radiologically.

Bone Neoplasms↗
PubMedDate not supplied

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