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Biomedical subjects

G Nagel

Publications and source records attributed to G Nagel.

125 records · Page 7Linked to original sources

[The morphological and functional integrity of cryo-preserved leukocytes].

Human peripheral blood lymphocytes were frozen by a simplified method which is described. Light and electron microscopic investigations of the frozen-thawed cells showed no significant morphological changes compared to the fresh cells; comparison of E-rosette formation and nonspecific acid esterase activity before and after cryoconservation afford evidence of a possible slight change in the percent relationship of T- and B-cells, whereas thymidine uptake values within normal range after stimulation with PHA and homologous cells demonstrate the functional integrity of the lymphocytes.

B-Lymphocytes↗

[Chromatographic investigation of the substrate properties of 8-bromo-ATP in the nucleoside diphosphate kinase reaction (author's transl)].

8-bromo-ATP is a substrate of nucleoside diphosphate kinase. Its reactivity is similar to that of ATP, and the reaction appears to be unaffected by the different conformations of these two substrates. The nucleoside diphosphate kinase reaction with 8-bromo-ATP cannot be monitored photometrically (optical test) using an NADH/NAD+-dependent enzyme system, because the product 8-bromo-ADP is not a substrate for pyruvate kinase. Measurements of the nucleoside diphosphate kinase reaction with 8-bromo-ATP therefore, were carried out by chromatographic analysis of the nucleoside-triphosphate/diphosphate ratio.

Adenosine Triphosphate↗

[The use of the Epidemiology Cancer registry Baden-Württemberg in the follow-up of the EPIC cohort].

The European Prospective Investigation into Cancer and Nutrition (EPIC) is a prospective multicentre study that has been implemented to further the understanding of the association between diet and chronic diseases with emphasis on cancer. In Heidelberg from June 1994 until October 1998 about 25,500 subjects aged 35 to 65 years in women and 40 to 65 years in men were recruited. Apart from extensive questions about food intake, the participants were also asked to provide detailed information about their smoking habits, physical activity, subjective well-being, medical history and use of medications. As well as completing the questionnaire and a personal interview, the participants also gave blood samples and anthropometiric measures and the blood pressure were taken in standardized manner. The analyses of the EPIC study will depend on achieving a comprehensive record of all new cancer cases, and all deaths, together with the corresponding cause of death, within the study population. To date all self-reported incident cancer cases are verified by comparing them with pathology reports and hospital records. They are then coded according to the coding list for the International Classification of Diseases (ICD-O2) issued by the World Health Organisation (WHO). Since at begin of the investigation in the study region no cancer registration existed, the participants are followed -up by interval questioning ('active follow-up'). In order to integrate increasingly the data of the Cancer registry Baden-Württemberg (EKR-BW) attempts were made to explore record linkage systems. For this purpose, in the years 2000, 2002, 2003 record linkages between EPIC-Heidelberg and EKR-BW were performed. Procedures were evaluated for performing an anonymous linkage of the EPIC data with the data of the EKR-BW. After a pilot project on the feasibility of the linkage the program was evaluated on the EPIC data, record linkages are performed regularly. Different coding systems were applied. Simultaneously, the EPIC data about on cancer cases among the Heidelberg study participants are passed on to the Cancer Registry, thus contributing to improve completeness of the registry. So far the active follow-up can not be replaced by passive follow-up through record linkage with the cancer registry, but in the long-term it may be possible. Since the technical requirements are complied with, attempts should be made to improve the completeness of the epidemiological cancer registry Baden- Württemberg.

Adult↗

Hexadecylphosphocholine: determination of serum concentrations in rats.

A sensitive and quantitative determination of the concentration of hexadecylphosphocholine in serum is described. After HPLC separation, the concentration of hexadecylphosphocholine is determined by phosphate analysis. According to this method, the half-life of hexadecylphosphocholine in serum rats is about 96 h. A steady-state serum concentration of 110 microM is reached after 2 weeks of daily treatment with 10 mg/kg hexadecylphosphocholine. The described method has general application for other compounds with similar structures. For instance, serum levels of alkyllysophosphocholines such as 1-0-octadecyl-2-0-methyl- racglycero-3-phosphocholine can be determined using this method.

Animals↗

Diurnal variations of active calcium transport in the intestine of pregnant and lactating rat.

Everted gut sac technique was used to study diurnal fluctuations of active calcium transport in the intestine of pregnant and lactating rats maintained under 12 hours light-dark cycle. At the second and third week of gestation an increase of calcium transport occurred in duodenum and adjacent part of jejunum at light phase, but the transport remained unchanged at darkness. Simultaneously the length of jejunal region able for active transport increased. In pregnant females around the term and in lactating mothers no diurnal differences in calcium transport were seen and at the 21st day of lactation the transport were seen and at the 21st day of lactation the transport was nearly equal in both duodenum and proximal jejunum. Restricted to darkness feeding of lactating rat evoked diurnal differences in jejunal but not in the duodenal transport.

Animals↗