Stereochemical analysis of the reaction catalyzed by human protein geranylgeranyl transferase.

Protein geranylgeranyltransferase type I (PGGTase-I) catalyzes the nucleophilic substitution reaction between the C(20) geranylgeranyl diphosphate (GGPP) and a protein-derived thiol to form a thioether linkage. Here, we describe the stereochemical outcome, at the isoprenoid C1, of the reaction catalyzed by human PGGTase-I. To accomplish this, the pentapeptide N-dansyl-GCVLL was first enzymatically prenylated by human PGGTase-I with either (S)-[1-(2)H]farnesyl diphosphate or (S)-[1-(2)H]GGPP. The prenylated products were then degraded to dipeptides using carboxypeptidase Y. After HPLC purification, the prenylated dipeptide products were analyzed by (1)H NMR spectroscopy. The final spectra were compared with the spectra from the same product obtained via chemical synthesis to deduce the stereochemistry of the PGGTase-I-catalyzed reaction. This comparison showed that the reaction proceeds with inversion of configuration with no detectable (< 6%) racemization. These results are more consistent with an associative-type mechanism, but they cannot be used to rule out a dissociative mechanism involving a rigid, solvent-sequestered, tight ion pair.

NMR investigations of duplex stability of phosphorothioate and phosphorodithioate DNA analogues modified in both strands.

Duplex formation from the self-complementary 12mer d(CGCGAATTCGCG) (Dickerson dodecamer) in which all phosphodiester linkages were replaced by phosphorothioate or phosphorodithioate linkages was studied using variable-temperature 1H and 31P NMR spectroscopy. Melting temperatures of the dodecamer, measured spectrophotometrically, showed significant decrease upon sulfur substitution (Tm 49 degrees C for the phosphorothioate and 21 degrees C for the phosphorodithioate, compared with 68 degrees C for the unmodified oligomer, in 1 M salt). Hyperchromicity observed upon melting of the dithioate was surprisingly low. NOESY spectra of the monothioate showed a cross-peak pattern characteristic for a right-handed duplex. Imino proton resonances of the duplex, shown by the mono- and the dithioate, were similar to those of the parent compound. In spite of monophasic melting curves, temperature dependence of the imino proton resonances and phosphorus resonances of the phosphorodithioate indicated heterogeneity with respect to base-pairing, compatible with the presence of a hairpin loop. Relaxation times (T1) of the imino protons in the phosphorothioate, determined by the saturation recovery method, were considerably shorter than in the unmodified oligomer. Base-pair lifetimes in the unmodified Dickerson dodecamer, determined by catalyst-dependent changes in relaxation rates of imino protons, were in the range of 2-30 ms at 20 degrees C. Strongly reduced base-pair lifetimes were found in the phosphorothioate analogue.

[Goiter incidence in Germany is greater than previously suspected]. / Strumaprävalenz in Deutschland grösser als bisher angenommen.

BACKGROUND: The data regarding goitre prevalence in Germany is based on calculation arising out of dissimilar studies conducted among inhomogeneous study groups. The aim of our study was to collect data towards prevalence of goitre, thyroid size and structure through a prospective nationwide survey conducted using identical examination methods and study protocol. PATIENTS AND METHOD: A total number of 6815 subjects belonging to various age groups and spread over 32 regions in Germany participated in our thyroid ultrasound study conducted with a 7.5 MHz transducer. Information regarding nutrition, use of iodised table salt and iodine containing medicine and/or substances were collected through a questionnaire. The volumetry and age related normal values were followed as per the guidelines set by Deutsche Gesellschaft für Endokrinologie. RESULTS: Enlarged thyroid was seen in 50% of 18 to 70 year age group, 52% of 11 to 17 year age group and in 21% of children up to 10 years. Focal lesions were detected in 2.5% of subjects below 18 years and in 30% of women and 21% of men over 18 years. A positive correlation between age, thyroid volume and number of thyroid nodules was seen. Up to 83% of the examined subjects admitted to using iodised table salt. Children consuming iodised salt were found to have smaller thyroid glands. No correlation was found between the consumption of iodised salt and thyroid size in the adolescent age group and young adults. CONCLUSION: The prevalence of goitre in Germany is higher than it has been reported. The study underlines the insufficiency of the present goitre prophylaxis. Only an iodine prophylaxis (table salt, food products, fodder) backed by legislative measures can bring about a real breakthrough.

Patient education programmes in obstructive airway disease. The Ingelheim Model for promoting health through patient education.

Chronic obstructive airway diseases (COAD) can be regarded as one of the major health problems needing environmental actions and screening programs for early detection and intensive patient education programs to cope with the needs of tertiary prevention. On the basis of our epidemiological study focused on COAD carried out in FRG (sample size August 1988: 63,000 participants) a patient education program has been developed and evaluated. In cooperation with general practitioners and pneumologists the program has been installed at practice and community level. The need for a patient education program has been assessed during the three years of the PNEUMOBIL-Project. It is not just a matter of cutting costs, but to a large extent a matter of the wellbeing of the patients and of reducing side effects to a minimum. The objective of the project can be split into three dimensions: (1) The cognitive aspect. Here significant lack of knowledge has to be overcome. At this point it has to be stated clearly that at the present time the medical community is not able to solve this problem on their own. (2) The psychomotoric aspect. Here the competent use of medication has to be trained. (3) The emotional aspect. The patient has to be motivated and integrated into the therapeutic process in a way that his compliance contributes significantly. The didactical concept consists of modules that can be used in varying sequences according to the needs of the target audience.(ABSTRACT TRUNCATED AT 250 WORDS)

Novel cyclopentenoid cyanohydrin rhamnoglucosides from flacourtiaceae1.

Two novel cyclopentenoid cyanohydrin glycosides, (1 S,4 R)-and (1 R,4 S)-1-[6- O-(alpha- L-rhamnopyranosyl)-beta- D-glucopyranosyloxy]-4-hydroxy-2-cyclopentene-1-carbonitrile, were isolated from seeds of the Indian medicinal plant HYDNOCARPUS PENTANDRA (F. Ham.) Oken (Flacourtiaceae) and characterized by optical rotations as well as (1)H-and (13)C-NMR spectra. The structural assignment is founded on these data and on degradation with alpha- L-rhamnosidase to the corresponding beta- D-glucopyranosides, epivolkenin and taraktophyllin, also present in the seeds in small amounts. Earlier reports of cyclopentenoid rhamnoglucosides from Passifloraceae are rejected.

16S ribosomal RNA analysis of Filibacter limicola indicates a close relationship to the genus Bacillus.

The phylogenetic relationship of the Gram-negative, filamentous gliding bacterium Filibacter limicola was analysed by 16S rRNA oligonucleotide cataloguing. In contrast to the proposed membership of this asporogenous species in the Flexibacteriaceae, Filibacter limicola clusters phylogenetically with the Gram-positive eubacteria Bacillus pasteurii, Sporosarcina ureae and the asporogenous species Planococcus citreus. The genetic relationship is supported by several common phenotypic properties.