Radiommunological measurement of leptin in plasma of obese and diabetic human subjects.

Studies in mice have identified the ob gene product, leptin, as a signaling factor regulating body weight homeostasis and energy balance. Defective production of the encoded protein may be one of the causes for the development of obesity. Using a high affinity antibody, that in immunohistochemical studies specifically stained human adipocytes, a radioimmunoassay was established and leptin immunoreactivity was quantified in plasma of lean and obese human subjects. Chromatographic analysis suggested that the immunoreactive material in plasma is identical to that found in extracts from human fat and represent a protein with a molecular size of approximately 16 kD. Fasting levels were measured in plasma of 75 lean and obese human subjects (body mass index (BMI) 17.7 - 87.3). The mean concentration of leptin in plasma of lean subjects (BMI < or = 28) was 69.3 +/- 36.9 fmol/ml plasma (mean +/- SD, n=27). The highest concentration measured in obese was 533.3 fmol/ml plasma. The levels showed a strong positive correlation with BMI (r=0.77, p<0.001). A subgroup of diabetic patients did not significantly differ in their leptin plasma levels from non-diabetic subjects with similar BMI.

Segmentation of microcalcifications in mammograms.

A systematic method for the detection and segmentation of microcalcifications in mammograms is presented. It is important to preserve size and shape of the individual calcifications as exactly as possible. A reliable diagnosis requires both rates of false positives as well as false negatives to be extremely low. The proposed approach uses a two-stage algorithm for spot detection and shape extraction. The first stage applies a weighted difference of Gaussians filter for the noise-invariant and size-specific detection of spots. A morphological filter reproduces the shape of the spots. The results of both filters are combined with a conditional thickening operation. The topology and the number of the spots are determined with the first filter, and the shape by means of the second. The algorithm is tested with a series of real mammograms, using identical parameter values for all images. The results are compared with the judgement of radiological experts, and they are very encouraging. The described approach opens up the possibility of a reproducible segmentation of microcalcifications, which is a necessary precondition for an efficient screening program.

Visualization of the mucosal villi on double-contrast barium studies of the small intestine by using a high molecular fraction of guaran.

Guaran is a water-soluble polysaccharide from the seed endosperm of Cyanopsis tetragonolobus. A high molecular fraction of guaran, when added to barium, enhances barium coating of the intestinal mucosa. This study reports its use to demonstrate the mucosal villi of the small intestine during double-contrast barium examination in the rat and in the human. In the animal model, individual villi were identified surrounded by pools of barium. In the human, a granular pattern caused by the villi was seen. Individual villi were visible with high-definition radiography. This was confirmed by microscopic studies of biopsy specimens in which the villi were shown to have the same diameters as the structures seen on high-definition radiography.

[Film digital and texture analysis for digital classification of pulmonary spot opacities]. / Filmdigitalisierung und Texturanalyse für die digitale Klassifizierung von Lungenfleckschatten.

The study aimed at evaluating the effect of different methods of digitisation of radiographic films on the digital classification of pulmonary opacities. Test sets from the standard of the International Labour Office (ILO) Classification of Radiographs of Pneumoconiosis were prepared by film digitisation using a scanning microdensitometer or a video digitiser based on a personal computer equipped with a real time digitiser board and a vidicon or a Charge Coupled Device (CCD) camera. Seven different algorithms were used for texture analysis resulting in 16 texture parameters for each region. All methods used for texture analysis were independent of the mean grey value level and the size of the image analysed. Classification was performed by discriminant analysis using the classes from the ILO classification. A hit ratio of at least 85% was achieved for a digitisation by scanner digitisation or the vidicon, while the corresponding results of the CCD camera were significantly less good. Classification by texture analysis of opacities of chest X-rays of pneumoconiosis digitised by a personal computer based video digitiser and a vidicon are of equal quality compared to digitisation by a scanning microdensitometer. Correct classification of 90% was achieved via the discribed statistical approach.

[Classification of spot-shaped lung changes by texture analysis]. / Klassifizierung fleckförmiger Lungenveränderungen durch Texturanalyse.

Classification of opacities in pneumoconiosis was accomplished by textural analysis in digitised chest x-rays. A good discrimination was achieved by a set of 10 parameters. These texture measures were computed by algorithms for edge detection, local extremes, difference statistics, the co-occurrence matrix and the power spectrum. The classes of the training set were classified correctly at 99%. A test set comprising additional classes that were not contained in the training set, was classified at 82%.

[Use of mucolytic agents and guaran Hepart (HP-7000) for imaging mucosal villi in double-contrast studies of the small intestine]. / Verwendung von Mukolytika und Guran HEPART (HP-7000) für die Darstellung der Schleimhautzotten bei der Doppelkontrastuntersuchung des Dünndarms.

It was the aim of this study to enhance the visualisation of mucosal villi by double contrast barium studies of the small bowel. Prior to the radiological examination a 2-day pretreatment with the mucolytic agents acetylcysteine or carbocisteine was effected. Double contrast studies were performed with a high-molecular fraction of guaran HEPART (HP-7000), a hydrocolloid isolated from the seed endosperm of C. tetragonolobus added into contrast-medium and distention medium. Compared to double contrast studies without mucolytic therapy, this procedure results in a better transparency and demonstration of the mucosal villi shown by a granular pattern in the radiographs. High quality visualisation of intestinal villi was achieved in all patients studied. A 2-day pretreatment with carbocisteine or acetylcysteine and the use of guaran in the double contrast barium study of the small bowel results in a greatly enhanced visualisation of mucosal villi.

[Roentgenological demonstration of pathological changes of the mucosa of the small intestine]. / Röntgenologischer Nachweis pathologischer Veränderungen der Dünndarmschleimhaut.

Use of a special high molecular guar preparation in small bowel contrast studies results in a roentgenological detection of the villous architecture of the small intestine. A diffuse villous atrophy results in a loss of the normal granular pattern. Segmental loss of granular mucosal texture is found in chronic radiogenic enteritis. In active Crohn's disease a coarser diffusely distributed granular appearance of the mucous surface occurs in addition to the segmental inflammatory changes. A coarse granular mucosal pattern with only segmental involvement is seen in mild malabsorption syndrome in the upper jejunum. Radiological signs for an intestinal protein loss syndrome is a coarse and weakly contrasted granular mucosal pattern in the lower ileum with moderate thickening of the jejunal folds and increased liquid content of the bowel.

[Sonographic determination of gastric emptying]. / Sonographische Bestimmung der Magenentleerung.

A reproducible method for the measurement of gastric emptying by real-time ultrasound is described. Gastric emptying was assessed by determining the decrease of the stomach area of the ultra-sound images during 55 min after fluid uptake. For the purpose of "validation", the gastric emptying time of 3 liquid test meals with different effects on gastric motility were measured.

[Multilevel structure isolation using modules based on the example of thoracic radiography]. / Modularisierte Strukturisolierung in Bildebenen am Beispiel von Lungenaufnahmen.

Conventional chest radiographs were digitized and processed by multilevel band pass filtering. By this procedure different structural components are isolated according to their local spatial frequencies. In chest radiographs a textural component can be separated from a skeletal component. Evaluation of radiological images is facilitated because changes can be looked for at relevant levels. A reconstruction of the image is possible, using different weighting factors to enhance interesting structural components.

Light-microscopical demonstration of different cell membrane structures of human peripheral blood lymphocytes (PBI).

Labelling of membrane structures in human peripheral blood lymphocytes is achieved by a Fe-(III)-hydroxide-glycane-complex. According to the distribution of labelled structures, coarse-granular clustered (about 80%) and fine-granular diffuse marked peripheral blood lymphocytes can be distinguished. Each of these populations seems to have morphologically discernible subpopulations.