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Biomedical subjects

P Landwehr

Publications and source records attributed to P Landwehr.

At least 19 recordsLinked to original sources
PubMed1992

[Taenia crassiceps infection in AIDS].

A 33-year-old patient with AIDS, and a history of episodes of Pneumocystis carinii pneumonia and cerebral toxoplasmosis, developed a subcutaneous paravertebral infiltrate, which at first resembled a haematoma. Over a period of several weeks, the lesion spread to cover almost the entire back. Initially, numerous investigations failed to reveal the aetiology. His general condition worsened progressively, and intermittent bleeding into the soft tissue of the back occurred, requiring transfusion. This was associated with the development of an isolated deficiency of clotting factor V and a fall in Quick values to 10%. On the 22nd day after admission, the infiltrate ruptured spontaneously, releasing blood and a large number of whitish spherical masses 2-3 mm in diameter. These were identified as Cysticerci longicolles, the larval form of Taenia crassiceps, a tapeworm occurring in Canidae. The blood clotting values returned to normal within two days of incision of the infiltrate and commencement of therapy with mebendazole (6 g/day) and praziquantel (3.6 g/day). The infiltrate subsequently regressed almost completely. After combination treatment for 2 weeks, treatment was continued with praziquantel alone, which, however, the patient stopped himself after 10 weeks. A recurrence at the same site 4 months later was successfully treated with a further course of mebendazole and praziquantel.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Interstitial lung diseases. A comparative study between a film-screen combination and a digital storage phosphor technic].

Chest examinations were carried out in 60 individuals using film-screen and digital storage phosphor techniques and identical radiation doses. 29 of these individuals were patients with interstitial pulmonary disease; 31 were normals. Postprocessing of the digital images was carried out with filtering using an unsharp mask and identical parameters for all patients. An ROC analysis using 10 observers showed no significant difference in the evaluation of the interstitial lung disease. Correlation analysis showed a significant positive correlation (p less than 0.001) for the findings in both techniques. Under the present circumstances, film-screen and digital storage phosphor technique are of equal value in the diagnosis of interstitial pulmonary disease.

Adult↗
PubMed1992

[The value of digital subtraction sialography compared to conventional sialography, salivary gland sonography and surgical findings].

In a prospective study DSA sialography, conventional sialography (100mm technique) and sonography of the salivary glands were performed in 124 patients. The results of imaging could be correlated with those of operation and/or histology in 70 patients. Performing sialography in only one projection DSA sialography is superior to the conventional technique. The results of DSA are equivalent to those of conventional sialography in more than one projection. DSA sialography is the method of choice demonstrating salivary calculi, whereas sonography is superior to DSA sialography in the detection of tumors. In the diagnosis of chronic inflammation of the salivary glands DSA is slightly superior to the other imaging modalities.

Adolescent↗
PubMed1992

[Pharmacokinetics of gadolinium-DTPA in chronic renal insufficiency requiring dialysis].

MRT with gadolinium-DTPA (0.1 mmol/kg body weight) was performed in 10 patients with renal insufficiency requiring dialysis and the clearance of gadolinium-DTPA was studied. After 3 dialysis on 3 successive days more than 97% of the initial concentration of gadolinium-DTPA had been eliminated. Average half-life was 1.87 hours. There were no side effects in any of the patients. Close laboratory observation of liver function showed no significant changes during the period of study. No contra-indication for the use of this contrast medium in patients with renal insufficiency requiring dialysis was found during this study.

Adult↗
PubMed1992

[The determination of myocardial mass by cardiac magnetic resonance tomography. The effect of section alignment and section distance].

The effect of section alignment and distance in volumetric determination of myocardial mass by means of cardiac magnetic resonance imaging (MRI) was studied in 19 isolated pig hearts. Double angulated views taken through the short axis of the heart with a slice thickness of 10 mm and slices at a distance of 0 mm, 1 mm, 3 mm and 5 mm produced accurate left ventricular measurements with cardiac MRI. Measurements in the long axis of the heart resulted in a marked underestimation of myocardial mass; depending on slice intervals, there was an error between 13% and 20%. In vivo measurements in 35 subjects confirmed the effect of section alignment. Measurements in the long axis of the heart produced results of 139.9 +/- 31.7 g, significantly less than measurements in the short axis of the heart of 157.8 +/- 32.3 g.

Adult↗
PubMed1992

[Response criteria for enzyme substitution in Gaucher disease].

Recently the intravenous enzyme replacement therapy with modified beta-glucocerebrosidase has become available for patients with M. Gaucher. We report here the considerable improvement of activity and vigor in a 5 year old girl with type 1 M. Gaucher administering 60 IU/kg every two weeks for 6 months. The platelet count increased from 82-96/nl to more than 150/nl and hemoglobin from 10.8 to more than 12 g/dl. Serum acid phosphatase decreased from 14.6 U/l to 5.9. U/l and angiotensin-converting enzyme from 327 to 102 U/l. The estimation of splenic volume by MRT showed a decrease by 40%, while liver size was not reduced within 6 months of therapy. MRT proved to be useful to demonstrate the bone marrow infiltration by Gaucher cells. The enzyme replacement therapy resulted in an objective response. No side effects have been observed so far. The extreme high treatment costs enforce a considerable dose reduction for maintenance therapy.

Acid Phosphatase↗
PubMed1991

[The frequency of false aneurysms of the femoral artery following heart catheterization and PTA (percutaneous transluminal angioplasty)].

In a prospective study, the arterial puncture site was studied sonographically in 1120 patients who had undergone cardiac catheterisation or angioplasty (renal or extremities). Contrary to the figures in the literature, there was an incidence of 3.84% of false aneurysms (catheters 5.26%, angioplasty 2.36%). Conventional sonography and colour-coded duplex sonography were of equal value for demonstrating false aneurysms, but colour-coded duplex sonography was superior for demonstrating their relationships and haemodynamic effects.

Adult↗
PubMed1991

[Vascular diagnosis with color-coded duplex sonography. A cost-benefit analysis].

In a retrospective study over two years, the costs of 2909 CCDS examinations were compared with 1893 digital subtraction angiograms. The cost of each CCDS examination was calculated as 147 DM and each DSA examination with intra-arterial contrast medium, or for shunt angiography was 709 DM. By using CCDS, it was possible to reduce the cost of angiographic examinations by 177,000 DM per year.

Angiography, Digital Subtraction↗
PubMed1991

[Color-coded duplex sonography of the extracranial arteries supplying the brain: diagnostic significance and sources of error in comparison with i.a. DSA].

The findings of color Doppler flow imaging of the extracranial cerebral arteries in 75 patients were compared with i.a. DSA. Carotid stenoses greater than 50% and carotid occlusions were shown by sonography with a sensitivity of 91% and a specificity of 97%. The severity of the stenosis was in agreement in 88% of cases using the two methods. Sonography of the vertebral arteries achieved a sensitivity of only 65% and a specificity of 88%. Sonographic examination of the ophthalmic artery in order to demonstrate carotid stenosis achieved a sensitivity of only 29% and provided no additional information. Retrobulbar kinking of the ophthalmic artery was found in 30/178 vessels and may be a cause of misinterpretation.

Angiography, Digital Subtraction↗
PubMed1991

[In vivo 31P-cardiac magnetic resonance spectroscopy: methods and the first clinical results].

31P-magnetic resonance (MR) spectra of the heart can be obtained from well-defined myocardial regions by combined MR imaging and variable selected volumes for spectroscopy. 31P-spectra of 33 volunteers and of 43 patients with dilated and hypertrophic cardiomyopathy and with coronary artery disease were quantified using a curve-fitting routine. To optimize our technique, we recorded unsaturated and partially saturated spectra in several volunteers. Relative peak areas and signal-to-noise ratios showed significant changes with varying pulse repetition times. Saturation factors were applied to correct spectra from volunteers and patients for the effects of partial saturation. Under resting conditions, peak areas of volunteers and patients from the various groups were statistically indistinct.

Adult↗
PubMed1991

Quantification of vascular stenosis with color Doppler flow imaging: in vitro investigations.

The accuracy of quantifying the degree of vascular stenosis with color Doppler flow imaging (7.5-MHz, linear array system) was determined in an experimental study carried out on six concentric and five eccentric model stenoses (cross-sectional area reduction, 13.4%-93.8%). The measurements were made with use of pulsatile flow at four different flow rates (70.8-339.0 mL/min). The degree of stenosis was calculated from the ratio of prestenotic to intrastenotic flow velocity. The most exact measurement of the degree of stenosis could be achieved with Doppler spectral analysis by determining the maximum peak systolic velocity (r = .994, y = 0.98x - 3.2). With the velocity values derived only from the color-coded image, it was also possible to find the most exact degree of stenosis (r = .995, y = 0.99x - 2.9). For quantification of stenosis, pre- and intrastenotic Doppler spectral analysis is no longer necessary if the stenosis can be imaged sufficiently with color Doppler.

Blood Flow Velocity↗
PubMed1991

[4 years' experience with a balloon-expandable endoprosthesis. Experimental and clinical application].

During a 4-year period of clinical application of the balloon-expandable Palmaz stent, a randomized trial comparing stent implantation and traditional balloon angioplasty of iliac arteries in arterial occlusive disease was started. The first long-term results, recorded after 2 years, indicate statistically significant differences in the complication rate (after stenting 2/62 and after angioplasty 5/69) and patency (greater than or equal to 70% of original lumen size upon stent implantation or balloon inflation: 95% after stenting and 72% after angioplasty). Clinical improvement after 2 years was 89% after stenting and 70% after angioplasty. Parallel to the clinical trials, experimental canine artery stenting was performed to evaluate differences in the long-term patency of stents exposed to restricted flow. Significant differences in neointimal healing were found between normally perfused stents and stents with artificially reduced flow: during the total observation period of 6 months the neointimal height was up to 200% higher in flow-restricted stents, while the histological composition of the neointima was the same as with normally perfused stents.

Angioplasty, Balloon↗
PubMed1991

[A ROC analysis for comparing contrast perception in grey scale reversal of digital images].

Based on ROC (receiver operating characteristic) analysis, contrast perception by eight physicians engaged in x-ray diagnostics for different lengths of time was examined in respect of inversion of grey scale values of digital x-ray film images. The ROC analysis showed a significantly superior contrast perception for imaging by the negative mode (bones white) than by the positive mode (bones black). With r* = + 0.61 a positive correlation was obtained between the period of the physicians' activity in x-ray diagnostics and the difference between the areas below the ROC curves for both imaging modes. Hence, the negative mode is to be preferred for diagnostic work based on digital x-ray film images.

Humans↗
PubMed1991

[Clinical value of sialography in digital and conventional imaging technique].

Digital subtraction sialography offers a new technique for the diagnosis of salivary gland disease. The basis of this technique is the removal of superimposed bony structures. Ninety-one patients (4-77 years old) with acute and chronic inflammatory disorders, chronic sialectasis, chronic sialolithiasis and tumours of various types underwent sialography using the digital subtraction technique. In addition, conventional sialography using a 100 mm camera and high resolution ultrasonography was performed. The results were compared with the histopathology and intraoperative findings. The digital subtraction technique is superior in recognition of inflammatory changes and chronic sialolithiasis, whereas ultrasonography is more sensitive in diagnosis and localization of tumours.

Adolescent↗