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Biomedical subjects

C Lehmann

Publications and source records attributed to C Lehmann.

At least 109 records · Page 6Linked to original sources
PubMed1976

5-Formyl-2'-deoxyuridine: cytostatic and antiviral properties and possible modes of action.

5-Formyl-2'-deoxyuridine (fdUrd) was prepared by a new method starting from thymidine and investigated for its influence both on proliferation of cultured mammalian cells and virus replication in vitro. The compound was found to have strong cytostatic and antiviral properties: 50% inhibition of proliferation of BHK 21/C13 cells or Ehrlich ascites tumour cells (EAT) was obtained at 4 - 10(-6) and 6 - 10(-6) M, respectively, while the treatment of pseudorabies virus with the same concentration resulted in about 1.5 log reduction of virus yield. A concentration of 1 - 10(-4) M inhibited cell proliferation by 80 to 100% while the virus yield was reduced by more than 3 orders of magnitude. All inhibitions can be prevented by thymidine.--DNA synthesis of EAT cells in vitro, as estimated by incorporation of [32P]-phosphate or low concentrations of [3H]-thymidine, was inhibited. Further biochemical experiments have provided indirect evidence that the compound is phosphorylated by thymidine and thymidylate phosphorylating enzymes. An inhibition of cell free DNA synthesis was found to be depending on a given period of preincubation with the compound (supposed to be needed for the formation of fdUrd 5'-triphosphate). This suggests that the 5'-triphosphate of fdUrd is an inhibitor of DNA polymerases and--by analogy with experiments with 5-formyluridine-5'-triphosphate and RNA polymerases [14]--may be used as an affinity label for this group of enzymes. It is concluded that the described cytostatic and antiviral effects of fdUrd are due to an intracellular "lethal" synthesis of the relevant phosphates which inhibit thymidylate synthetase (as had been found earlier to occur with the chemically prepared nucleotide in cell free extracts [1, 2]) and DNA synthesizing enzymes.

Animals↗
PubMed1976

[Bronchial cancer in Berlin, capital of the G.D.R. 2. communication. lung cancer detection between 1955 and 1973 (author's transl)].

In Berlin, capital of the G.D.R., more than 8,600 cases of bronchial cancer were observed in the period 1955 to 1969 and in 1973/4. Number of cases has increased from one 5-years period to the following period. Incidence of lung cancer in men increased especially in higher age groups whereas in female a rising incidence can be seen in all age groups. Duration of history is no good measure of health behaviour and of diagnostic quality. Distribution of clinical stages gives reliable information on the situation of detection. With rising age, the proportion of advanced stages increases. Stage distribution has not changed during the observation period and no measurable progress towards earlier detection of lung cancer has been achieved. In the same time, proportion of elderly lung cancer patients rose considerably and the chances of radical surgical treatment grew worse. Nevertheless the resection rate has increased. It seems that the quality of specialized surgical care has made some progress. Some conclusions can be drawn for cancer control: Prophylactic examinations are to be concentrated on high risk groups. Patients with suspicion of lung cancer shall be admitted to the specialist without delay. Development of nonsurgical methods of therapy for cancer of the lung is an important goal.

Adult↗
PubMed1975

[Protein screening in wheat and broad bean specimens in Gatersleben].

Actually and in future times plant proteins will constitute the main and primary source of proteins in animal feeding and human alimentation. Therefore, the main efforts to resolve the world nutrition problems are focused on the increase of the protein production and the improvement of the nutritional quality of plant seed proteins. In this regard plant breeding occupies one of the most important strategic positions. With the aim of selecting forms with elevated grain protein content and improved protein quality the systematic screening of collections of wild forms and cultivated cereals and leguminoses constitutes a pre-requisite of successful breeding work in relation to the above-mentioned task. In 1970 the Central Institute of Genetics and Investigation of Cultivated Plants at Gatersleben, GDR, belonging to the Academy of Sciences, started a systematic protein screening with about 10000 wheat, 6500 barley and 450 broad bean specimens, which are parts of the World Collection of Cultivated Plants at this institute. Protein determination was performed by the traditional KJELDAHL-method. Limiting amino acids, essentially lysin from cereal grains, were estimated by automatic ion exchange technique. The annual analytic capacity amounted to 6000 to 8000 samples. First results and problems of wheat- and broad bean-screening are reported in the present publication.

Amino Acids↗