Magnetoresistance of rolled-up Fe3Si nanomembranes.

Magnetotransport of individual rolled-up Fe(3)Si nanomembranes is investigated in a broad temperature range from 4.2 K up to 300 K in pulsed magnetic fields up to 55 T. The observed magnetoresistance (MR) has the following pronounced features: (i) MR is negative in the investigated intervals of temperature and magnetic field; (ii) its magnitude increases linearly with the magnetic field in a low-field region and reveals a gradual trend to saturation when the magnetic field increases; (iii) the MR effect becomes more pronounced with increasing temperature. These dependences of MR on the magnetic field and temperature are in line with predictions of the spin-disorder model of the spin-flip s-d interaction assisted with creation or annihilation of magnons, which is expected above a certain critical temperature. Comparison of the MR features in rolled-up and planar samples reveals a substantial increase of the critical temperature in the rolled-up tube, which is attributed to a new geometry and internal strain arising in the rolled-up nanomembranes, influencing the electronic and magnetic properties of the material.

The LUCAS* consortium: objectives of interdisciplinary research on selected aspects of ageing and health care for older people in an urban community.

BACKGROUND: Decline in functional competence is a major determinant of older persons' needs, the development of dependency, use of care, clinical outcome and mortality. The interactions between rising life expectancy and changes in morbidity and disability warrant interdisciplinary research on functional disability, health promotion and prevention. The LUCAS (Longitudinal Urban Cohort Ageing Study) research consortium was established to study particular aspects of functional competence, its changes with ageing, to detect preclinical signs of functional decline, and to address questions on how to maintain functional competence and to prevent adverse outcome. The questions originate from problems encountered in practical health care provision in different settings, i.e. community, hospital and nursing home. METHODS: The subprojects apply a longitudinal cohort follow-up study, an embedded randomised controlled intervention, cross-sectional comparative, and prospective intervention studies. CONCLUSION: The results will provide instruments to screen for preclinical signs of functional decline and concrete recommendations to sustain independence and prevent adverse outcomes in older age in daily practice.

[The Longitudinal Urban Cohort Ageing Study (LUCAS)]. / Die Longitudinal-Urban-Cohort-Ageing-Studie (LUCAS).

BACKGROUND: The interactions between rising life expectancy, morbidity and development of disability warrant interdisciplinary research on functional disability, health promotion and prevention as well as healthcare provision for older people. Therefore, the interdisciplinary LUCAS (Longitudinal Urban Cohort Ageing Study) research consortium of university and non-university institutions was established and is coordinated by the research department of the Albertinen-Haus at the University of Hamburg. The aim is to study particular aspects of functional competence, the changes with ageing, to detect pre-clinical signs of functional decline and to address questions on how to maintain functional competence and to prevent adverse outcomes. The research questions have their origin in problems of practical healthcare provision in the different settings of communities, hospitals and nursing homes. The articles of LUCAS subprojects report selected results from the first project phase (2007-2010) which was funded by the German Federal Ministry of Education and Research (BMBF) (Research program"Health in the elderly").). METHODS: The LUCAS subprojects 1-7 applied a true cohort study design with embedded randomized controlled intervention studies and cross-sectional studies for comparative purposes and to prepare intervention studies to be performed in the second project phase. CONCLUSIONS: Results from the first project phase provided new instruments to screen and to assess functional competence in older people (population-based screening). In the second project phase these will be evaluated according to practicability and usefulness. Furthermore, parts of the results will be used by the health reporting system in Hamburg and for intervention studies performed by LUCAS subprojects during the second project phase (LUCAS II).

Cultivar and Spacing Effects on Transmission of Phytophthora parasitica in an Ebb-and-Flow Subirrigation System.

Phytophthora parasitica was transmitted within 6 weeks from vinca (Catharanthus roseus) plants growing in infested potting mix, on the drain end of ebb-and-flow benches, to plants in noninfested potting mix. Transmission of Phytophthora was very low when potting mix was not pasteurized. When potting mix was steam pasteurized, infection of plants, disease incidence, and severity increased with time and decreased with distance from plants in infested pots. The cultivar Pretty in Pink was more susceptible to infection by P. parasitica than cv. Peppermint Cooler, allowing more rapid and severe disease development as well as pathogen dissemination and transmission. Pot spacing did not significantly affect transmission of P. parasitica on an ebb-and-flow bench.

[Preventive treatment of mothers and their babies in a day care setting]. / Präventive Arbeit mit Müttern und ihren Babys im tagesklinischen Setting.

Certain aspects of the communication between mother (and father) and baby are of major influence on the developmental outcome of the child. Mentally ill mothers in psychiatric day care are considerably limited in their communicative abilities, especially in themes of developmental relevance. As a consequence of their inherent ego weakness the mothers' flexible adaption to the babies' needs is impaired. Because of their own emotional neediness mothers are not sufficiently sensible and responsive to the babies' signals. Almost all of the mothers feel aggressive impulses towards their babies. Indication for day care depends to an essential part on the mothers' reflective function concerning aggression. Although there is some danger of child abuse, the joint treatment is considered to prevent early attachment disorders and/or a pathologic developmental outcome in the child. In addition, mother-baby-therapy is indicated in cases of severe regulation disorders. The specific models of our therapy are illustrated in two case examples.

Attachment pili from enterotoxigenic Escherichia coli pathogenic for humans.

Pili from enterotoxigenic Escherichia coli pathogenic for humans have been isolated by adsorption to the surface of erythrocytes followed by thermal elution. The pili are composed of two protein subunits with molecular weights of 13,100 and 12,500 as determined by sodium dodecyl sulfate-gel electrophoresis. These pili also bind to human buccal cells under temperature conditions (37 degrees C) which prevent the binding of these pili to the erythrocytes. Analogous temperature effects on binding have previously been observed with whole bacterial cells. This binding can be inhibited by antiserum prepared against the isolated pili.

Hemagglutination and adhesiveness of toxigenic Escherichia coli isolated from humans.

Toxigenic strains of Escherichia coli isolated from humans were studied for adherence to human buccal mucosal epithelial cells. The E. coli strains were labeled with 3H-amino acids or fluorescein isothiocyanate. Toxigenic E. coli strains varied in their ability to adhere in the presence of mannose. Of 32 toxigenic strains examined, 52% bound to the buccal cells, whereas none of 8 control strains did so (Mann-Whitney U test, P =0.007). The control strains were nontoxigenic E. coli isolates from humans, enterotoxigenic E. coli isolates from animals, and E. coli K-12 containing the K88 or K99 plasmid; these strains exhibited only background-level adherence in this assay. Among the toxigenic E. coli strains that bound to human buccal mucosal cells, there was no correlation with mannose-resistant hemagglutination (MR-HA) of guinea pig and human erythrocytes. Screening 32 strains, we found the following phenotypes: (i) MR-HA+, buccal adherent; (ii) MR-HA+, buccal nonadherent; (iii) MR-HA-, buccal adherent. Presumably the third group represents strains with another type(s) of surface attachment components not involved in the MR-HA reaction. Our findings indicate that a number of bacterial surface structures can function in MR-HA and buccal adherence.

Heterogeneity and distribution of lipopolysaccharide in the cell wall of a gram-negative marine bacterium.

Lipopolysaccharide (LPS) extracted from Alteromonas haloplanktis 214, variants 1 and 3, separated into three fractions when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The fractions appeared in the gels as bands which stained for carbohydrate with the periodate-Schiff reagent. Variant 1, a smooth variant of the organism, and variant 3, a rough colonial variant, produced identical banding patterns. Under similar conditions, LPS from Neisseria meningitidis SDIC, Escherichia coli O111:B4, and Salmonella typhimurium LT2 gave rise to one, two, and three bands, respectively. LPS from Pseudomonas aeruginosa (ATCC 9027) failed to stain clearly with the reagent used. The banding pattern obtained with A. haloplanktis LPS was found not to be due to artifacts produced by the extraction or solubilization procedures employed or to the amount of protein associated with the LPS. When Triton X-100 replaced sodium dodecyl sulfate in the electrophoresis system, LPS failed to migrate into the gel. The lipid A but not the degraded polysaccharide fraction obtained by mild acid hydrolysis of the LPS migrated into the gel on electrophoresis. The three carbohydrate-staining bands obtained with A. haloplanktis LPS and referred to as LPS I, II, and III, in order of increasing electrophoretic mobility, were detected in each of the three outer layers of the cell wall of the organism. Estimations from densitometer scans indicated that 17% of the total LPS in the cell was present in the outer membrane, with the remainder divided almost equally between the loosely bound outer layer and the periplasmic space. Of the three fractions, LPS II was present in each of the layers in greatest amounts. Less LPS I and more LPS III were present in the outer membrane than in the periplasmic space. Pulse-labeling studies indicated that LPS I and II may be synthesized independently, whereas LPS III, which appeared only in cells in the stationary phase of growth, may be a degradation product of LPS I.

Serotypes of attachment pili of enterotoxigenic Escherichia coli isolated from humans.

Pili from enterotoxigenic Escherichia coli isolated from humans have been partially purified, and antisera have been prepared. These pili were initially attached to erythrocytes and then removed by thermal elution for purification. Three distinct antigenic types of pili have been identified. Antisera against these three pili types reacted with 60 of 106 (56%) enterotoxigenic E. coli isolated from humans but not with nontoxigenic, normal human fecal isolates of E. coli nor with enterotoxigenic E. coli strains isolated from animals. There was no correlation between pili serogroup and any of the following toxin production (heat labile, heat stable, or both), O antigenic type, geographical source of isolation, or mannose-resistant hemagglutination patterns of various erythrocyte types.

Attachment of human and pig (K88) enterotoxigenic Escherichia coli strains to either human or porcine small intestinal cells.

Enterotoxigenic Escherichia coli strains pathogenic for humans and enterotoxigenic E. coli strains pathogenic for pigs producing the K88 pili antigen both bound to isolated small intestinal cells from either humans or pigs. Neither the K99 enterotoxigenic E. coli (from lambs and calves) nor the rabbit pathogenic strain RDEC-1 bound to human or pig small intestinal cells under the same conditions.

Effect of tetracycline on the attachment of K88+ enterotoxigenic Escherichia coli to porcine small-intestinal cells.

The attachment of six strains of K88+, porcine pathogenic, enterotoxigenic Escherichia coli to isolated porcine intestinal mucosal cells was decreased following growth in the presence of concentrations of oxytetracycline below the minimal inhibitory concentration (MIC). The decrease in binding by the wild-type strains was detected at concentrations of drug as low as 0.001 microgram/ml, which was greater than four orders of magnitude below the MIC. When drug resistance was induced in these six strains, there was still a decrease in binding when the bacteria were grown in the presence of tetracycline. This decrease was comparable to the decrease in binding capacity of the wild-type strains caused by growth in the presence of tetracycline. In contrast, when one strain (G1108E) was made tetracycline resistant by the introduction of the R16 plasmid, the antibiotic had less effect on the binding of this strain than on the wild-type strain; however, growth in the presence of antibiotic still decreased adhesion. Overall, oxytetracycline decreased the adhesion of wild-type, induced-resistant, and genetically resistant K88+ enterotoxigenic E. coli to porcine small-intestinal cells, and this effect occurred at antibiotic concentrations several orders of magnitude below the MIC.

Entamoeba histolytica cytotoxin: purification, characterization, strain virulence, and protease activity.

A heat-labile cytotoxin was isolated from virulent strains of axenically cultivated Entamoeba histolytica. Strains of E. histolytica representing a spectrum of virulence as determined in animal and in vitro models of disease were examined for cytotoxic activity. Extracts of virulent strain HM1 possessed marked cytotoxic activity, those of moderately virulent strain 200 showed intermediate activity, and those of avirulent strains 303 and Rahman showed no activity. The cytotoxin was partially purified from the cell-free supernatant of sonicated E. histolytica HM1 trophozoites by ammonium sulfate precipitation and gel filtration. Cytotoxic activity was stable in a narrow pH range (6-7.2) and in 1 M NaCl, urea, and guanidine. Specific immune rabbit and human antiserum as well as the protease inhibitors aprotinin, pepstatin, and leupeptin inhibited cytotoxicity. The partially purified cytotoxin did not have any detectable degradative enzymatic activities. Thus, virulent strains of E. histolytica possess an immunogenic cytotoxic protein which may be important in the pathophysiology of amoebiasis.

Attachment of enterotoxigenic Escherichia coli to human intestinal cells.

An adherence test was developed with human ileal cells isolated from patients with a long-standing ileostomy by saline lavage through the stoma. Enterotoxigenic Escherichia coli isolated from humans bound to the human ileal cells to a greater extent (1.2 x 10(6) bacteria bound) than did control E. coli strains, including K99 pili antigen-producing strains (whether originally isolated from pigs or calves), the rabbit pathogen RDEC-1, the laboratory-derived nontoxigenic strain 334LL, or human normal fecal strains. However, K88 strains, either K88ab or K88ac, bound to the human ileal cells as well as did enterotoxigenic E. coli. Ileal cells isolated from two donors with different blood types behaved similarly. These cells remained viable and retained their binding ability for at least 3 days when stored in tissue culture medium at 4 degrees C.

Antimicrobial substance from a human Lactobacillus strain.

Lactobacillus sp. strain GG, which was isolated from the feces of a normal person, produced a substance with potent inhibitory activity against a wide range of bacterial species. It inhibited anaerobic bacteria (Clostridium spp., Bacteroides spp., Bifidobacterium spp.), members of the family Enterobacteriaceae, Pseudomonas spp. Staphylococcus spp., and Streptococcus spp., as demonstrated by a microbiological assay; however, it did not inhibit other lactobacilli. The inhibitory activity occurred between pH 3 and 5 and was heat stable. Bactericidal activity against Escherichia coli was demonstrated at a dilution of 1:128. The inhibitory substance was distinct from lactic and acetic acids. It had a low molecular weight (less than 1,000) and was soluble in acetone-water (10:1). Because of these characteristics, the inhibitory material could not be considered a bacteriocin; it most closely resembled a microcin, which has been associated previously with members of the family Enterobacteriaceae.

Induction of cystine transport and other stress proteins by disulfiram: effects on glutathione levels in cultured cells.

Disulfiram (Antabuse) (DSF) has been reported to protect rats and other animals from the effects of hyperbaric hyperoxia at 4 to 6 ATA (atmospheres). In contrast, DSF and diethyldithiocarbamate (DDC), its metabolite, accelerate the toxic effects in rats of 100% oxygen at 1 to 2 ATA. We have examined the effects of DSF and DDC on glutathione (GSH) levels in bovine pulmonary artery endothelial cells and Chinese hamster ovary cells. Increases in intracellular GSH occurred 8 to 24 h after addition of DSF to the culture media. These increases in intracellular GSH were associated with increases in the rate of uptake of cystine into the cells. DDC was a less effective inducer of cystine uptake and increased intracellular GSH levels than was DSF. At the concentrations used, neither DDC nor DSF caused significant decreases in intracellular superoxide dismutase levels. Exogenous sulfhydryl compounds including GSH and cysteine partially blocked the induction of cystine transport by DSF or DDC, suggesting that the induction might be mediated through a sulfhydryl reaction between DSF and some cellular components. The increases in GSH in the cultured cells were not significant by 4 h of exposure. In contrast, other stress proteins including heme oxygenase are induced by 2 to 4 h after DSF addition. In previously reported in vivo studies, DSF treatment protected against hyperbaric oxygen damage after as little as 1 to 4 h pre-exposure. This suggests that effects of DSF exposure other than GSH augmentation may be responsible for the protective effects seen in vivo.