Dynamically disordered hydrogen bonds in the hureaulite-type phosphatic oxyhydroxide Mn5[(PO4)2(PO3(OH))2](HOH)4.

We report the temperature evolution of hydrogen bond (HB) chains and rings in Mn5[(PO4)2(PO3(OH))2](HOH)4 to reveal conduction pathways based on difference Fourier maps with neutron- and synchrotron x-ray diffraction data. Localized proton dynamics for the five distinct hydrogen sites were observed and identified in this study. Their temperature evaluation over ten orders of magnitude in time was followed by means of quasielastic neutron scattering, dielectric spectroscopy, and ab initio molecular dynamics. Two out of the five hydrogen sites are geometrically isolated and are not suitable for long-range proton conduction. Nevertheless, the detected dc conductivity points to long-range charge transport at elevated temperatures, which occurs most likely (1) over H4-H4 sites between semihelical HB chains (interchain-exchanges) and (2) by rotations of O1-H1 and site-exchanging H4-O10-O5 groups along each semihelical HB chain (intrachain-exchanges). The latter dynamics freeze into a proton-glass state at low temperatures. Rotational and site-exchanging motions of HOH and OH ligands seem to be facilitated by collective motions of framework polyhedra, which we detected by inelastic neutron scattering.

Identification of influence factors for the implementation of communication curricula in dental education.

INTRODUCTION: The aim of the study was to reveal possible obstacles or advantages for the implementation of a dental communication curriculum. It was questioned whether (i) universities with a communication curriculum in medicine realise the same development in dentistry, (ii) the existence and usage of a learning objectives catalogue is a main factor to facilitate the implementation, and (iii) it is more easy to establish with a lower number of students. MATERIAL AND METHODS: Data of two recently published surveys were taken as the basis for further analysis. The quality of the curricula was evaluated by a scoring system. Correlations were calculated between the scores and possible influence factors. A t test for paired samples was accomplished to reveal differences between medical and dental curricula, and a Mann-Whitney U test to identify differences in schools with and without the usage of a learning objectives catalogue. RESULTS: No significant correlation was found between the quality scores of medical and dental schools; t tests revealed significant differences between them (P = .004). Correlation between cohort size and quality of the curriculum was marginal. Mann-Whitney U test revealed significantly higher quality scores for dental schools using a learning objectives catalogue (P = .001). CONCLUSIONS: The existence of a learning objectives catalogue might facilitate the implementation of communication curricula at dental schools. A missing notable curriculum in the corresponding medical school should not detain from a respective campaign in the dental curriculum. Large student numbers should also not discourage from developing a communication curriculum.

Do virtual patients prepare medical students for the real world? Development and application of a framework to compare a virtual patient collection with population data.

BACKGROUND: An important aspect of virtual patients (VPs), which are interactive computer-based patient scenarios, is authenticity. This includes design aspects, but also how a VP collection represents a patient population and how a patient is presented in a VP scenario. Therefore, our aim was to analyze VP scenarios integrated into the combined internal medicine and surgery curriculum at the University of Munich (LMU) and compare the results with data from the population in Germany. METHOD: We developed a coding framework with four main categories: patient data, patient representation, diagnoses, and setting. Based on the framework we analyzed 66 VP and compared the results with data from the German healthcare system. RESULTS: Especially in the categories of patient data and patient representation, the VPs presented an unrealistic image of the real world; topics such as unemployment, disability, or migration background were almost non-existent. The diagnoses of the VPs and the onset of diseases were comparable with the healthcare data. CONCLUSIONS: An explanation for the lack of representativeness of the patient data and representation might be a trend to create VPs based on fictional patient stories with VP authors trying to minimize complexity and cognitive load for the students. We suggest raising awareness among VP authors concerning personalized representations of patients without overwhelming their students. Our framework can support educators to assess the authenticity and diversity of a VP collection.

Teaching and assessment of communication skills in undergraduate dental education - a survey in German-speaking countries.

INTRODUCTION: Teaching communication is perceived to be of importance in dental education. Several reports have been published worldwide in the educational literature describing modifications of the dental curriculum by implementing the teaching of communication skills. Surveys which evaluate the current state of training and assessment of communication skills in dental education in different countries exist already in some countries, but little information is available about German-speaking countries. MATERIAL AND METHODS: In a cross-sectional study with the aim of a census, all 36 dental schools in Germany (30), Austria (3), and Switzerland (3) were surveyed. RESULTS: The present survey revealed that at 26 of the 34 dental schools (76%), communication skills training has been implemented. Training of communication skills mainly takes place between the 6th and the 9th semester. Ten schools were able to implement a partly longitudinal curriculum, while the other sites only offer stand-alone courses. Of the 34 dental schools, six assess communication skills in a summative way. Three of those schools also use formative assessments for their students. Another seven sites only use formative assessment. From the various formats of assessment, OSCE is mentioned most frequently. CONCLUSION: The necessity to train and assess communication skills has reached German-speaking dental schools. The present survey allows an overview of the training and assessment of communication skills in undergraduate dental education in German-speaking Europe.

Facilitating in vitro tape stripping: application of infrared densitometry for quantification of porcine stratum corneum proteins.

Infrared (IR) densitometry is a highly practical method recently proposed for protein analysis during in vivo tape stripping. However, this method has not yet been validated for the quantification of porcine stratum corneum (SC) proteins. Therefore, the aim of this study was to establish calibration curves for the analysis of adhesive tapes removed from porcine ear skin. To this end, the protein absorption (as determined via IR densitometry) was correlated with the protein content determined with the Micro BCA™ protein assay after extraction of the tapes. The obtained linear regressions confirm that IR densitometry is suitable for the quantification of not only human, but also porcine, SC proteins. The pattern of protein removal observed with porcine skin differs from that of human skin due to more pronounced corneocyte clustering and deep 'canyons', which necessitates specific evaluation of porcine skin samples and a working protocol that takes this into account. The presented data will facilitate future analysis of porcine SC proteins during in vitro tape stripping.

Anti-atherosclerotic effect of microbial hyaluronate lyase from group B streptococci.

The effect of the microbial hyaluronic acid splitting enzyme hyaluronate lyase produced by Streptococcus agalactiae was investigated in vitro in human atherosclerotic plaque specimens and in vivo on Watanabe heritable hyperlipidaemic rabbits (WHHL) as an animal model for familiar hypercholesteraemia. The in vitro presence of the enzyme caused a partial destruction of the atherosclerotic plaque surfaces as well as releasing of glucuronic acid and solid calcium-containing materials from pieces of atherosclerotic plaques in human arteries. Accordingly hyaluronic acid seems to be the main component for anchoring of calcium deposits on the plaque surfaces. Repeated intravenous injections of hyaluronate lyase in WHHL rabbits resulted in a tendency of decreased formation of atherosclerotic plaques. The observed effects are discussed to be primary the result of the splitting of hyaluronic acid in the vessels.

Antimicrobial and anti-inflammatory activity of four known and one new triterpenoid from Combretum imberbe (Combretaceae).

Combretum imberbe is used widely in Africa inter alia for treating bacterial infections. In addition to four known triterpenoids, 1alpha,3beta-dihydroxy-12-oleanen-29-oic (1), 1-hydroxy-12-olean-30-oic acid (2), 3,30-dihydroxyl-12-oleanen-22-one (3), and 1,3,24-trihydroxyl-12-olean-29-oic acid (4), a new pentacyclic triterpenoid (1alpha,23-dihydroxy-12-oleanen-29-oic acid-3beta-O-2,4-di-acetyl-L-rhamnopyranoside) 5 has been isolated through a bioassay-guided procedure from the leaves of Combretum imberbe. The structures of the compounds were elucidated on the basis of 1D and 2D NMR experiments, as well as mass spectrometric data. All compounds isolated had moderate (62 microg/ml) to strong (16 microg/ml) antibacterial activity (MIC values) against Staphylococcus aureus and Escherichia coli, with 1 and 5 being most active. Compounds 1 and 5 also showed very strong inhibition of 3alpha-hydroxysteroid dehydrogenase with an IC(50) of 0.3 microg/ml. Compound 5 indicated a moderate anti-proliferative (GI(50)=16.5 and 13.2 microg/ml) and cytotoxic activity (CC(50)=17.6 micro/ml) against K-562, L-929 and HeLa cell lines, respectively. The results of this study give credence to the ethnomedicinal use of Combretum imberbe and expand our knowledge on the biological activity of its metabolites.

Randomised clinical trial: the effects of a multispecies probiotic vs. placebo on innate immune function, bacterial translocation and gut permeability in patients with cirrhosis.

BACKGROUND: Probiotics may correct intestinal dysbiosis and proinflammatory conditions in patients with liver cirrhosis. AIM: To test the effects of a multispecies probiotic on innate immune function, bacterial translocation and gut permeability. METHODS: In a randomised, double blind, placebo-controlled study, stable cirrhotic out-patients either received a daily dose of a probiotic powder containing eight different bacterial strains (Ecologic Barrier, Winclove, Amsterdam, The Netherlands) (n = 44) or a placebo (n = 36) for 6 months and were followed up for another 6 months. RESULTS: We found a significant but subclinical increase in neutrophil resting burst (2.6-3.2%, P = 0.0134) and neopterin levels (7.7-8.4 nmol/L, P = 0.001) with probiotics but not with placebo. Probiotic supplementation did not have a significant influence on neutrophil phagocytosis, endotoxin load, gut permeability or inflammatory markers. Ten severe infections occurred in total; one during intervention in the placebo group, and five and four after the intervention has ended in the probiotic and placebo group, respectively. Liver function showed some improvement with probiotics but not with placebo. CONCLUSIONS: Probiotic supplementation significantly increased serum neopterin levels and the production of reactive oxygen species by neutrophils. These findings might explain the beneficial effects of probiotics on immune function. Furthermore, probiotic supplementation may be a well-tolerated method to maintain or even improve liver function in stable cirrhosis. However, its influence on gut barrier function and bacterial translocation in cirrhotic patients is minimal.

Particulate nitrocellulose as a solid phase for protein immobilization in immuno-affinity chromatography.

The use of nitrocellulose paper as a solid phase matrix for protein immobilization and its application in immunoaffinity chromatography is described. Pieces of nitrocellulose paper were frozen in liquid nitrogen and ground to a powder (NCP) which was then fractionated according to particle size by repeated sedimentation/resuspension cycles in water. The flow properties of different NCP fractions were compared with those of Sephadex G-50. Protein binding capacity and binding dynamics were investigated in a model system with bovine serum albumin (BSA) in phosphate buffered saline. Applications of the material are illustrated by batch chromatography for the removal of anti-carrier protein antibodies from a hapten antiserum and by affinity purification of a hapten-specific antibody fraction using NaSCN elution from haptenated NCP. Furthermore, the applicability of the material in column chromatography is demonstrated by elution of a monospecific fraction of anti-fluorescein antibodies from a hapten/carrier mixed bed column by excess of soluble hapten. The results demonstrate that NCP chromatography appears to be a cheap and useful alternative to many other chromatographic media used for protein immobilization.

Improvement of antisera raised against complex antigen mixtures by the use of heterologous sources of antigen for immunization.

Polyspecific antisera against antigen mixtures are important tools for many experimental purposes. However, following immunization with extracts containing a great number of different proteins, many antigens remain non-immunogenic. Therefore, the improvement of the antibody spectrum of antisera is an essential goal in maximising the power and applicability of many serological analyses. In the present report we demonstrate that the additional use of heterologous (i.e., antigenically related, but not identical) antigen mixtures for immunization increases the variety of antibodies in polyspecific antisera as well as the antibody titer against weak immunogens.

A method for the detection of serologically crossreacting antigens both within and between protein mixtures: the western cross blot.

The method described in the present paper permits the detection of antigenically related proteins within or between different antigen mixtures. For this purpose two separate SDS-polyacrylamide gels are run (the antigen mixture is applied to the entire width of the gel) and each gel is blotted on to a separate nitrocellulose paper. One sheet ('donor sheet') is incubated with antiserum and placed on to the other blot ('receptor sheet') so that the antigen bands are perpendicular to each other. Subsequently the antibodies from the donor sheet are blotted on to the receptor sheet in alkaline borate buffer containing 1 M NaSCN, which dissociates antigen-antibody complexes. After the removal of the donor sheet the receptor sheet containing the transblotted antibodies is equilibrated in phosphate-buffered saline in order to reconstitute the binding conditions. Antibodies which have bound to receptor antigens during this equilibration period are detected by the use of a peroxidase labelled 2nd antibody. Because each band on the donor sheet crosses each band on the receptor sheet during the transfer, the antibodies from each band of the donor sheet are able to react with each antigen band of the receptor sheet. The validity of the method was established by demonstrating the crossreactivity of a polyclonal antiserum against the intact bovine gamma globulin molecule with the heavy and light chain subunits (and partial reduction products of the molecule) and the absence of crossreactivity between heavy and light chains. In a second experiment crossreacting antigens of different molecular weight were detected within several strains of Escherichia coli. In addition, comparisons of different strains of Escherichia coli revealed crossreacting antigens of identical as well as of different molecular weight.

A non-expressed transgene as a cell marker for the investigation of cellular traffic after splenic autotransplantation.

The investigation of cellular interactions during the regeneration of splenic transplants depends upon distinguishing host cells from graft derived cells. As a cell marker which, in contrast to many other marker systems, does not affect histocompatibility, the non-expressed transgene mMT-HGHRH-1 was introduced by mating into NMRI inbred mice to generate the transgenic mouse line BSM. By transplanting non-transgenic NMRI splenic tissue into transgenic BSM hosts, host derived cells could be identified in the transplants by in situ hybridization after regeneration. In a reciprocal approach, implant derived cells were detected in a transgenic transplant after 3 weeks of regeneration in a non-transgenic host. Relative amounts of transgenic cells in transplant cross-sections were estimated from the signal intensity of autoradiographs by densitometry and computer analysis. This approach could be broadly applied in studies of transplantation systems.

DNA immunization is associated with increased activity of type I iodothyronine 5'-deiodinase in mouse liver.

Inflammatory cytokines in vitro are believed to be involved in the regulation of type I iodothyronine 5'-deiodinase (5'-DI) activity. The present study was undertaken to investigate in vivo effects of DNA immunization of mice on the 5'-DI activity in the liver. A mammalian expression vector encoding the beta-galactosidase (pCMV-betagal) was used for intradermal immunization. Furthermore, immunostimulatory CpG motifs, which induce the expression of IL-6, IL-12, IL-18, TNF-alpha/beta and IFN-gamma were coinjected as oligodeoxynucleotides. From our data we conclude that the activity of 5'-DI in mouse liver when compared to non-immunized animals (100%) was found to be significantly enhanced by DNA immunization 2 weeks (175.7%) or 3 weeks (192.6%) after the plasmid injection. In addition, the activity of the 5'-DI in mouse liver was markedly enhanced 2 weeks (252.4%) or 3 weeks (243.3%) after the injection when CpG motifs were applied together with the plasmid DNA.

DNA immunization in vivo down-regulates nuclear all-trans retinoic acid receptors in mouse spleen cells.

Nuclear retinoid receptors - retinoic acid inducible transcription factors - participate in pathways influencing many components of the immune system. In the present study in vivo effects of DNA-based immunization of mice on binding parameters of all-trans retinoic acid receptors (RARs) in spleen cell nuclei was investigated. A eucaryotic expression vector encoding the gene for the model enzyme beta-galactosidase of Escherichia coli (pCMV-beta) was used for intradermal injection. Furthermore, immunostimulatory CpG motifs, which stimulate the expression of various cytokines and may serve as a 'danger signal' for the mammalian immune system, were coinjected as oligodeoxynucleotides. The results demonstrate that the concentration of RARs was significantly reduced in the late phase of the primary immune response (21 days after injection of plasmid DNA-indicated by high affinity IgG antibodies and IFN-gamma expression). Coinjection of CpG motifs did not change the course of the humoral response but enhanced and accelerated the proliferative response and expression of IFN-gamma, which correlated with the reduced RARs concentration.

Studies on the hydrogenation of the progestagen dienogest in vivo and in vitro in the female rabbit.

The biotransformation of the progestagen dienogest (17 alpha-cyanomethyl-17 beta-hydroxy-4,9-estradien-3-one) was studied in vivo in female rabbits and in vitro by liver homogenates from female rabbits and rats. In vivo, in the female rabbit, 3H-dienogest was the subject of an extensive biotransformation. A significant difference between the composition of the urinary and biliary metabolite patterns of dienogest was found. While in the urinary metabolite pattern more polar metabolites dominated, in bile of animals with a bile fistula, a dienogest metabolite of medium polarity was prevalent. This main metabolite of dienogest was identified by MS, 1H- and 13C-NMR spectroscopy and CD measurement of an enzymatic dehydrogenation product as the tetrahydro metabolite 17 alpha-cyanomethyl-5 alpha-estr-9-en-3 beta,17 beta-diol. Thus, in vivo, the 4,9-dien-3-oxo-19-norsteroid dienogest is hydrogenated to a 5 alpha H-9-en metabolite. In vitro, however, 3H-dienogest was only poorly transformed by liver homogenates from both species, whereas 3H-levonorgestrel and 3H-3-keto-desogestrel were converted partially by liver homogenates from female rabbits and completely by liver homogenates from female rats. The principal biotransformation reactions of levonorgestrel and 3-ketodesogestrel were the reduction of the 3-oxo group to 3-OH and the 5 beta- and 5 alpha-hydrogenation of the 4-double bond by homogenates of female rabbit liver and female rat liver, respectively. A dihydro metabolite of dienogest, in which the 3-oxo group had been reduced to 3-OH, was isolated in small amounts from the incubation with rabbit liver homogenate. The data indicate that the enzymatic hydrogenation of the 4-double bond of the 4,9-dien-3-oxo steroid dienogest is inhibited in vitro. The hindered hydrogenation reaction in vitro has to be seen in association with the 9-double bond in the steroid molecule.

Differences in ion-channel formation by ampullosporins B, C, D and semisynthetic desacetyltryptophanyl ampullosporin A.

Peptaibol-type ampullosporins B (2) and D (4) are capable of forming ion-conducting pores in planar lipid bilayer membrane prepared from soybean phosphatidylcholine in a similar manner as it was shown for ampullosporin A (1). However, the isomeric ampullosporin C (3) was required in 20-fold higher concentration to afford a comparable effect. In contrast to 1, 2, 3 and 4, the desacetyltryptophanyl ampullosporin A (5) failed to form ion channels. The results suggest that the sequence of amino acids especially at positions 8-10, the nitrogen-terminal acetyl residues and tryptophane are major factors determining ion-channel formation within bilayer membranes. The differences in membrane activities were comparable to the observed biological activities.

Ampullosporin, a new peptaibol-type antibiotic from Sepedonium ampullosporum HKI-0053 with neuroleptic activity in mice.

Ampullosporin (I; Ac-Trp-Ala-Aib-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Gln-Leu-Aib-Gln-Leuol) was isolated from the mycelium of Sepedonium ampullosporum as a new 15-membered peptaibol-type antibiotic. The structure was determined by mass spectrometric and two-dimensional NMR experiments. Ampullosporin displays narrow-spectrum antibacterial and antifungal activity, induces pigment formation by Phoma destructiva, causes hypothermia and decreased spontaneous locomotor activity in mice in dosages > 1 mg/kg.

Griseorubins, a new family of antibiotics with antimicrobial and antitumor activity. II. Biological properties and antitumor activity of the antibiotic complex griseorubin.

The antibiotic complex griseorubin has antimicrobial activity against Gram-positive as well as -negative bacteria, mycobacteria, mycoplasma and protozoa in vitro but it is not active against yeast and fungi. Tests with transplantable rodent tumors indicate that griseorubin is inhibitory to the growth of lymphatic leukemia L1210 in mice and Zajdela ascites hepatoma in rats. The acute LD50 of griseorubin in mice is 50 mg/kg of body weight when given intraperitoneally. Attempts to potentiate the antitumor activity by complexing with DNA proved to be unsuccessful.

New 1-O-acyl alpha-L-rhamnopyranosides and rhamnosylated lactones from Streptomyces sp., inhibitors of 3 alpha-hydroxysteroid-dehydrogenase (3alpha-HSD).

Chemical screening with extracts of Streptomyces sp. (strain GT 61150) resulted in the detection, isolation, and structure elucidation of two new acyl alpha-L-rhamnopyranosides (1 and 2) and three new rhamnosyllactones A, B1 and B2 (3 approximately 5). Rhamnosyllactones B1 and B2 were obtained as a 5:1 mixture. The structures were confirmed by spectroscopic analysis, especially 2D-NMR techniques. The rhamnosyltransferase of our strain is able to connect the sugar moiety to heteroaromatic carboxylic acids and enols. The metabolites 1 and 4/5 as well as previously reported acylrhamnosides 6 approximately 11 inhibit the enzyme 3alpha-hydroxysteroid-dehydrogenase (3alpha-HSD).

Aurantimycins, new depsipeptide antibiotics from Streptomyces aurantiacus IMET 43917. Production, isolation, structure elucidation, and biological activity.

Aurantimycins A (1), B (2) and C (3) were isolated from the mycelium of Streptomyces aurantiacus JA 4570 as new representatives of the azinothricin group of hexadepsipeptide antibiotics. Their structures were settled by X-ray diffraction analysis of crystalline aurantimycin A (1), high field homo- and heteronuclear 2D NMR experiments, high-resolution mass spectrometry and amino acid analysis. Aurantimycins are characterized by a new side chain containing fourteen carbon atoms. They display strong activity against Gram-positive bacteria and cytotoxic effects against L-929 mouse fibroblast cells.