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H Preuss

Publications and source records attributed to H Preuss.

14 recordsLinked to original sources
PubMed2005

[Comparison of four digital and one conventional radiographic image systems for the chest in a patient study with subsequent system optimization].

PURPOSE: Using a patient study to prove the clinical relevance of a comparison of five different radiographic systems for the chest conducted with an anthropomorphic chest phantom. Depending on the results, it was tested whether the performance of a modern digital system with a transparent imaging plate can be improved by changing the post-processing of the image. METHOD: Chest radiographs of patients were taken with a CsI/aSi-flat panel detector (FDR), transparent imaging plate (tDLR), selenium drum detector (DSR), conventional storage phosphor plate (DLR) and asymmetrical screen-film-system (aFFS), and compared using image criteria scoring (ICS) and visual grading analysis (VGA) for anatomical structures (modified criterions of the EUR 16 260 EN guidelines). After optimizing the post processing, the images of the tDLR-system were evaluated once more in a phantom ROC study and patient VGA study. RESULTS: The flat panel detector-system proved to meet best the anatomical image quality criteria, followed by DSR, tDLR, aFFS and DLR. The modified post processing of the tDLR-images resulted in a significantly better detection of simulated pathological lung-structures, but improved the perceptibility of anatomical structures only slightly. CONCLUSIONS: The results of the patient VGA study and the phantom ROC study are similar and considered valid. The new digital imaging systems with flat panel detector and transparent imaging plate provide the best image quality of the tested radiographic devices for chest imaging, assuming that all system components are attuned and optimized for the type of structure to be detected. Image processing is of primary importance for system optimization.

Humans↗
PubMed2005

Effects of a novel formulation of essential oils on glucose-insulin metabolism in diabetic and hypertensive rats: a pilot study.

BACKGROUND: Insulin resistance and its most severe form type 2 diabetes mellitus are rapidly increasing throughout the world. It is generally recognized that natural products with a long history of safety can increase insulin sensitivity. AIMS: The present investigation examined the ability of various combinations of essential oils such as fenugreek, cinnamon, cumin, oregano, etc. to enhance insulin sensitivity. As a first approximation, we examined the effects of these natural products on Zucker fatty rats (ZFRs), a model of obesity and insulin resistance, and spontaneously hypertensive rats (SHRs), a model of genetic hypertension. MATERIAL AND METHODS: Water or essential oils were given orally via droplets, and insulin sensitivity was estimated by systolic blood pressure (SBP) changes and circulating glucose and/or insulin concentrations. RESULTS: We have found that the ability to alter SBP in rat models is the most sensitive early index of insulin sensitivity. The combined essential oils lowered circulating glucose levels and SBP in both ZFRs and SHRs, suggesting that these natural products are enhancing insulin sensitivity. The second series of studies examined two additional combinations of essential oils along with the original formula. The major differences were in the types and proportions of individual oils contributing to a given formula. CONCLUSIONS: Although all the three formulae decreased SBP in ZFRs, one of the formulae was more effective than the others in lowering circulating glucose in the glucose tolerance testing. Accordingly, some essential oils may be added to the long list of natural products that can affect insulin sensitivity.

Administration, Oral↗
PubMed2003

[Chest radiography: ROC phantom study of four different digital systems and one conventional radiographic system].

PURPOSE: To compare the diagnostic quality of five different radiographic systems used in chest radiography for visualization of differently configured, clinically relevant pathologic pulmonary structures. MATERIALS AND METHODS: Four digital detector systems using as detection unit a CsI/aSi-based flat panel detector, a transparent imaging plate, a selenium detector and a conventional storage phosphor plate were analyzed for this study, as well as an asymmetrical film-screen system. The analyzed imaging material consisted of radiographs of an anthropomorphic chest-phantom with superimposed simulated pulmonary structures. The images were evaluated for different pathologic structures by a newly developed multiple structure ROC (ms-ROC). RESULTS: The performance of each system was found to have a strong structure-related variability. The flat panel detector system had the best overall performance. The theoretical advantage of the 4k-matrix of the transparent imaging plate over the 3k-matrix of the flat panel detector was only confirmed for reticular structures. CONCLUSIONS: In addition to comparing the image quality of the different systems, this study shows that the performance of a radiographic system depends on the structure to be analyzed. The modified ROC (ms-ROC) provides valid results with less effort.

Humans↗
PubMed2002

[Optimized image processing with modified preprocessing of image data sets of a transparent imaging plate by way of the lateral view of the cervical spine].

PURPOSE: To improve the diagnostic quality of lateral radiographs of the cervical spine by pre-processing the image data sets produced by a transparent imaging plate with both-side reading and to evaluate any possible impact on minimizing the number of additional radiographs and supplementary investigations. MATERIAL AND METHODS: One hundred lateral digital radiographs of the cervical spine were processed with two different methods: processing of each data set using the system-imminent parameters and using the manual mode. The difference between the two types of processing is the level of the latitude value. Hard copies of the processed images were judged by five radiologists and three neurosurgeons. The evaluation applied the image criteria score (ICS) without conventional reference images. RESULTS: In 99 % of the lateral radiographs of the cervical spine, all vertebral bodies could be completed delineated using the manual mode, but only 76 % oft the images processed by the system-imminent parameters showed all vertebral bodies. Thus, the manual mode enabled the evaluation of up to two additional more caudal vertebral bodies. The manual mode processing was significantly better concerning object size and processing artifacts. This optimized image processing and the resultant minimization of supplementary investigations was calculated to correspond to a theoretical dose reduction of about 50 %. CONCLUSION: The introduction of optimized organ programs for the upper and lower cervical spine based on the 12-bit data of the images should improve the evaluation of the lateral radiograph of the cervical spine without reducing the latitude value.

Cervical Vertebrae↗
PubMed1980

[A case of twins with probable superfetation (author's transl)].

A twin case of disputed paternity with probable superfetation is reported. The putative father could be excluded as the father of Twin F by HLA, GLO, and Ss typing results, but could not be excluded as the father of Twin S, with a probability of paternity for this twin of 99.995%. A birth weight difference of 450 g and the evidence for additional sexual intercourses by the mother suggest the very rare event of a superfetation.

Blood Group Antigens↗
PubMed1979

Tubular function in adult polycystic kidney disease.

Various tubular functions were assessed in 10 patients with polycystic kidney disease (PKD). Three relatively unique abnormalities were apparent in many of these patients -- an inability to maximally concentrate urine, a decrease in ability to lower urine pH after acute acid challenge, and an inability to excrete adequate amounts of ammonium during persistent acid challenge. The defects in urinary acidification and ammonium excretion in PKD have not been previously described.

Adult↗
PubMed1978

Effects of medium pH on p-aminohippurate transport in rat kidney fragments.

Addition of many oxidizable substrates to medium often enhances p-aminohippurate (PAH) transport by incubating renal tissue. Since the oxidation of various substrates by rat kidney tissue may change medium pH and this pH change has not been considered by many in conclusions, we followed the effects of medium pH on the magnitude and kinetics of in vitro PAH transport. Two previous studies employing rat kidney slices reported different optimal medium pH for PAH accumulation, i.e. pH 6.5 and pH 8.0. By repeating these studies over a wide range of medium pH, we confirmed the presence of enhanced steady state accumulation relative to pH 7.4 at two separate pH ranges, one at pH 6.7--6.9 (+ 15%), and the other at pH 7.7--7.9 (+ 22%). PAH influx, as measured by early tissue accumulation, was not different at pH 7.4 and 7.8; while at pH 6.8, it actually decreased. It was only later in the incubation that accumulation was greater at pH 6.8 and 7.8. Probably due to the small stimulation in steady state accumulation at either pH, we could not discern, by the methodology currently available, if this was secondary to augmented influx, decreased efflux, or a combination of both in the latter part of incubation. We conclude that the contribution secondary to medium pH changes must be considered when evaluating the effects of various substrates on PAH accumulation by kidney slices.

Aminohippuric Acids↗