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U Seiffert

Publications and source records attributed to U Seiffert.

9 recordsLinked to original sources
PubMed2005

A pattern recognition tool for quantitative analysis of in planta hyphal growth of powdery mildew fungi.

The development of fungal pathogens can be quantified easily at the level of spore germination or penetration. However, the exact quantification of hyphal growth rates after initial, successful host invasion is much more difficult. Here, we report on the development of a new pattern recognition software (HyphArea) for automated quantitative analysis of hyphal growth rates of powdery mildew fungi on plant surfaces that usually represent highly irregular and noisy image backgrounds. By using HyphArea, we measured growth rates of colonies of the barley powdery mildew, Blumeria graminis f. sp. hordei, on susceptible and induced-resistant host plants. Hyphal growth was not influenced by the resistance state of the plants up to 48 h postinoculation. At later time points, growth rate increased on susceptible plants, whereas it remained restricted on induced-resistant plants. This difference in hyphal growth rate was accompanied by lack of secondary haustoria formation on induced-resistant plants, suggesting that induced resistance in barley against Blumeria graminis is caused mainly by reduced penetration rates of primary as well as secondary appressoria leading, finally, to fewer and less-developed fungal colonies. No evidence was found for reduced nutrient-uptake efficiency of the primary haustoria in induced-resistant leaves, which would be expected to have resulted in reduced hyphal growth rates during the first 48 h of the interaction.

Ascomycota↗
PubMed1997

Growing 3D-SOMs with 2D-input layer as a classification tool in a motion detection system.

This paper describes the employment of an 'Adaptive Growing Three-Dimensional Self-Organizing Map' for the classification of images. First a short description of growing SOMs is given and the fundamental advantages are mentioned. Then an extension of the original SOM from two to three dimensions with growing feature is presented. By means of some selected examples the general behavior of the algorithm is illustrated.

Algorithms↗
PubMed1993

Bone metabolism before and after irradiation with ultraviolet light.

The beneficial effects of ultraviolet light on cutaneous vitamin D synthesis, calcium metabolism, and bone formation are well known. Regarding the increasing fear of side effects from ultraviolet B (UV-B), lamps with less energy in the UV-B range have been developed. Two spectra with differences in the emission of UV-B have therefore been evaluated for their influence on calcium metabolism. A group of 24 healthy male volunteers was subdivided into two treatment groups. Group 1 was exposed to lamps with higher energy of total UV-B but less energy at the wavelengths below 300 nm than the lamps used in group 2. All subjects were irradiated ten times within 12 days. Exposure time was 3 min in the first session and time of exposure was increased by 10% in every following irradiation (suberythematous doses only). Before the first irradiation, 3 days after the last exposure, and after 4 more weeks, the serum parameters of bone metabolism were determined by standard laboratory methods. Significantly increased levels of 25-hydroxyvitamin D3 were found in both groups. There was only a slight increase of 1,25-dihydroxyvitamin D3. Parathyroid hormone decreased significantly in group 2 only. The data would suggest beneficial effects on bone metabolism for both regimens. The observed effects were more pronounced when shorter wavelengths (group 2) were applied, although the total energy of UV-B was lower in these lamps.

Adult↗
PubMed1976

Bone histology in incipient and advanced renal failure.

Quantitative bone histology (micromorphometry of undecalcified sections, analysis under polarized light; fluorescence microscopy with tetracycline double labelling) as well as serum and urinary chemistry (creatinine clearance, parathyroid hormone, ionized Ca, bone phosphatase, pH), were studied in 50 patients with incipient to advanced (glomerular filtration rate, 80 to 6 ml/min x 1.73 m2 renal insufficiency. In incipient renal failure, indirect evidence of parathyroid hormone excess was found in the skeleton (empty osteoclastic lacunae, woven osteoid). Osteoclastic surface resorption was abnormally high when GFR fell below 50ml/min x 1.73 m2. With the tetracycline double-labelling technique, a mineralization defect was demonstrable in many but not all patients.

Acidosis↗
PubMedDate not supplied

Tumor markers, liver function tests and symptoms in 115 patients with isolated colorectal liver metastases.

Development of the hybridoma technique has made the identification of several new tumor antigens possible. Although it was hoped that they would be more tumor-specific, none of these markers are found exclusively in tumor or in serum of tumor patients. Compared with carcinoembryionic antigen (CEA) and liver function tests, the roles of these markers (CA 19-9, CA 125, CA 15-3) were prospectively evaluated in 115 patients with colorectal liver metastases. Patients were classified according to tumor volume (T1 less than 25%, T2 25-75%, T3 greater than 75%), and the extension of infiltration (solitary/multiple/diffuse; unilateral, bilateral). Patients with benign liver or biliary disease served as a control group (n = 63). Overall sensitivity was 87% for *1, 50% for *2 and 38% for *3, with a significant correlation with tumor size. CEA serum levels were elevated in 88% of all patients. CA 19-9 was less sensitive: positive in 59%. Because of some complementary elevations, the combined use of CEA, CA 19-9 and CA 125 raised sensitivity to 94%. CA 19-9 and LDH could be useful for confirmation because of their higher specificity; however, the specificity of CEA rose to 93% on using a cut-off of 10 ng/ml instead of 3 ng/ml. The results indicate that CEA and CA 19-9 as well as liver function tests are helpful for preoperative staging in conjunction with imaging procedures before liver resection or regional chemotherapy.

Antigens, Neoplasm↗