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Biomedical subjects

G Büttner

Publications and source records attributed to G Büttner.

At least 19 recordsLinked to original sources
PubMed2004

Strategies for the detection of potential beet necrotic yellow vein virus genome recombinations which might arise as a result of growing A type coat protein gene-expressing sugarbeets in soil containing B type virus.

We have searched for beet necrotic yellow vein virus (BNYVV) populations with a recombined genome which could possibly arise when transgenic sugarbeets expressing the coat protein gene of A type BNYVV are grown in soil containing Polymyxa betae carrying B type BNYVV, in soil samples from previous field release experiments and in a greenhouse model experiment. In order to accelerate the potential evolution of virus populations with recombined genomes in the model experiment, eight successive crops of sugarbeet plantlets were grown in the same soil samples over a period of 3 years. For the sensitive detection of recombined BNYVV genomes, we used nested PCRs with sense primers that are preferentially extended on the A type BNYVV sequence in the region of the coat protein gene and antisense primers which are preferentially extended on the B type BNYVV sequence in a region downstream of the coat protein gene which is not present in the transgene. Controls with mixtures of sap from plants which were singly infected with A or with B type BNYVV only revealed that, unless proper precautions are taken, PCR-mediated recombination artifacts may readily be produced. A method was developed that is able to detect A type/B type recombinant RNA molecules up to dilutions of one to a million in pure B type RNA molecules. Inspite of this high sensitivity we failed to detect any BNYVV with a recombined genome in the transgenic plants of the model experiment or at the sites of the previous field release experiments.

Base Sequence↗
PubMed2001

[Thalidomide in the treatment of cutaneous and systemic sarcoidosis].

The clinical courses of two patients suffering from generalized or disseminated cutaneous sarcoidosis are described. Both were treated with thalidomide 2 x 100 mg/day, later 100 mg/day. After 8 to 12 months of treatment the skin and systemic lesions had resolved almost completely.

Adult↗
PubMed2001

[Effects of selective item repetition and of finger tapping on primary school children's recall performance in a multi-trial experiment. An empirical analysis of two basic assumptions of the optimation model].

The optimization model, which is a subtheory within the fuzzy-trace theory, claims that verbal items are retrieved from long-term memory in a weak-->strong-->weak order. This cognitive triage pattern of recall has been attributed to the dynamic interaction of memory strength, episodic activation, and output interference. According to a basic assumption of the optimization model, inter-item strength differences are invariant in free-recall experiments. Additionally it is assumed that an accumulation of output interference is responsible for the rotation from weak into strong words. This assumption implies that the cognitive triage pattern should be less pronounced and the recall performance should be poorer when the level of output interference is high at the beginning of recall. Due to age differences in the sensitivity to the effects of output interference the cognitive triage pattern and the recall performance should be more adversely affected in younger children when the level of output interference is high during the recall phase. In order to examine the two assumptions of the optimization model, second and fourth graders learned two lists of semantically unrelated words which were presented once, twice, or four times within the lists. The level of output interference was artificially increased by finger tapping throughout recall production. The empirical findings did not confirm the assumptions of the optimization model. Memory strength of the items did change as a result of the experimental manipulation. Additionally, recall performance was not poorer in the finger-tapping condition though the cognitive triage pattern was somewhat less pronounced in this condition. Age-related effects of output interference on the cognitive triage pattern and the level of recall could not be shown.

Age Factors↗
PubMed2000

Structure and variability of the 3' end of RNA 3 of Beet soil-borne pomovirus--a virus with uncertain pathogenic effects.

PCR products representing c. 550 3' terminal bases of Beet soil-borne pomovirus (BSBV) RNA 3 were compared for sources of this virus from all major sugarbeet-growing areas in Germany. In none of these areas conspicious symptoms could be attributed to the presence of BSBV. Single strand conformation polymorphism analyses suggested that the BSBV genome may be very variable. This was confirmed by nucleotide sequence analysis. Each PCR product which was analysed showed sequence differences to others. Even the PCR products obtained from plants grown in the same soil sample were different. The highly variable nature of the BSBV genome is in contrast to the much more conserved nature of the Beet necrotic yellow vein virus genome. By means of the STAR programme a secondary structure was predicted for the 3' end of BSBV RNA 3, in which some areas are highly conserved, whereas others are characterized by a clustering of nucleotide exchanges.

3' Untranslated Regions↗
PubMed1997

Altered catecholamine synthesis and degradation in the epidermis of patients with atopic eczema.

Patients with atopic eczema have significantly higher norepinephrine levels in plasma than healthy controls. In addition, significantly higher levels of the essential cofactor (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (6BH4) were found in this patient group. Cell extracts from epidermal suction blister roofs revealed only half the normal activity of phenylethanolamine-N-methyl transferase (PNMT) together with a threefold induction of the norepinephrine-degrading enzyme monoamine oxidase A (MAO-A). Taken together, these results support earlier observations of a defective catecholamine/adrenoceptor signal in patients with atopic eczema.

Adolescent↗
PubMed1994

Cytotoxicity of 6-biopterin to human melanocytes.

(6R)5,6,7,8 tetrahydrobiopterin (6-BH4) is an important cofactor in the regulation of melanogenesis in melanocytes, where it controls: (a) the supply of L-tyrosine from L-phenylalanine via phenylalanine hydroxylase, and (b) regulates directly dopaquinone formation from L-tyrosine via tyrosinase. 6-BH4 undergoes redox-cycling by its oxidation to quinonoid dihydrobiopterin (qBH2) and to 6-biopterin through consecutive two electron oxidation reactions. The oxidized cofactor 6-biopterin (0.2 x 10(-6) M) is extremely cytotoxic to human melanocytes under in vitro conditions. Consequently, its reduction to 6-BH4 via q-BH2 is essential to melanocyte viability. In addition, the results herein show for the first time that human thioredoxin reductase has the capacity to reduce 6-biopterin to q-BH2 where further reduction to 6-BH4 follows via dihydropteridine reductase or reduced glutathione.

Biopterins↗
PubMed1991

Fine structure of microfilariae in the skin of onchocerciasis patients after exposure to amocarzine.

Transmission electron microscopy was used to demonstrate the effects of amocarzine (CGP 6140) on the fine structure of Onchocerca volvulus microfilariae (mf) in skin biopsies from patients treated orally in Guatemala or transepidermally exposed in Liberia. After 6-10 hours exposure to the drug most mf did not show any alterations and only a few mf contained increased numbers of vacuoles in the cytoplasm and clefts between cuticle and hypodermis. At 20-48 hours after treatment most of the mf showed distinct signs of damage. Most frequently seen was disintegration of the cytoplasm of the afibrillar portion of the muscle cells. Some mf showed also disintegration of the myofilaments and of the internal structure of the mitochondria in the muscle cells. Other signs were progressive separation of the cuticle from the hypodermis, increase of intracellular vacuoles and clefts and in some mf condensation of the cytoplasm. The type and the site of the morphological alterations were the same after both forms of amocarzine administration. The degree of morphological changes increased with the length of time of exposure to the drug. Microfilariae with morphological alterations were nearly always surrounded by adherent host cells, mostly eosinophils and macrophages.

Administration, Cutaneous↗
PubMed1984

Frequency of apolipoprotein A-I mutants in the German population.

A randomly chosen population in the area of Westphalia (West Germany) was screened for apolipoprotein A-I mutants. About 5000 individuals were investigated and compared with a group of 1300 patients who had undergone coronary angiography. Four electrophoretically different apolipoprotein A-I-mutants (named Münster-1 to 4) were discovered. Five non-related probands were observed in the group of the unselected patients and three non-related probands in the group of coronary angiography patients. In most cases the familial nature of the abnormality was confirmed by pedigree analysis.

Adult↗