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S Maier

Publications and source records attributed to S Maier.

At least 91 records · Page 5Linked to original sources
PubMed1992

Morphine- and naltrexone-induced modification of palatability: analysis by the taste reactivity test.

We used the taste reactivity (TR) test, a direct measure of the hedonic properties of a tastant, to assess in Sprague-Dawley rats the ability of morphine (an opiate agonist) and naltrexone (an opiate antagonist) to modify the palatability of a bitter quinine solution and a sweet sucrose solution. Morphine reduced the aversive hedonic properties of both novel and familiar quinine solution (0.05% and 0.1%) but did not modify the palatability of 20% sucrose solution. Naltrexone reduced the positive hedonic properties of sucrose solution (2% and 20%) but did not modify the palatability of 0.05% quinine solution. The pattern of results suggests that the modification of feeding produced by opiate agonists and antagonists may be mediated by an hedonic shift in the palatability of the tastant.

Animals↗
PubMed1992

Partial characterization of coliphage WPK and a comparison with coliphage T3.

Coliphage WPK was originally isolated from sewage in Kiel, Germany, because its plaque diameter continued to expand for days. Electron microscopy revealed an isometric capsid with dimensions of 54 nm between opposite apices, and a short, noncontractile tail 16 nm long, placing phage WPK into morphogroup C1. The nucleic acid of phage WPK was linear double stranded DNA. The host ranges of phages WPK and T3 were identical. Of ten E. coli strains tested for host range, two were resistant and of eighteen other Enterobacteriaceae only four were susceptible. Seven gram-negative species which are not members of the Enterobacteriaceae were refractory. However, there were differences in plaque morphology and plaque expansion between the two phages. Phage T3 plaques expanded for at least seven days on E. coli B only, while phage WPK plaques expanded for at least seven days on four strains of E. coli. The buoyant density of WPK, determined by isopycnic density gradient centrifugation in CsCl, was 1,508 g/ml which was significantly different than that of T3 at 1.493 g/ml (P less than 0.05). Phage-encoded proteins were examined for each phage using [35S]methionine incorporation, SDS-PAGE, and autoradiography. Of thirty proteins identified in phage WPK and twenty-eight in phage T3, only fourteen were of the same size in both. We concluded that phage WPK was distinct, but related to T3.

Coliphages↗
PubMed1989

Velocity profiles in the normal human abdominal aorta: a comparison between ultrasound and magnetic resonance data.

Evolving magnetic resonance (MR) procedures were utilized to validate one-dimensional ultrasonic (US) Doppler profiles in vivo on the basis of this alternative noninvasive method of assessing blood velocity. Corresponding velocity profiles were acquired by both US and MR in the abdominal aorta of 10 healthy volunteers. The ultrasound velocities recorded throughout a cardiac cycle along the anterio-posterior aortic diameter were compared to their spatial and temporal MR counterparts. Correlation coefficients ranging from 0.92 to 0.97 and regression slopes from 0.86 to 1.13 indicate a high degree of correspondence between the two modalities and increase the confidence in the fidelity of velocity profiles obtained with both procedures.

Adult↗
PubMed1988

Quantitative flow measurements on phantoms and on blood vessels with MR.

A broad spectrum of MR methods has been published in the last few years for the visualization and the quantification of flow in human blood vessels. We describe the results of an extended study to measure the flow quantitatively using the MR phase modulation method. A gradient echo sequence which allows short repetition times was synchronized with the ECG. The instantaneous velocity profiles and the integrated flow rate can be determined throughout the cardiac cycle in up to 45 consecutive time intervals. The instantaneous velocity distributions can be displayed as 2D profiles over the lumen of the blood vessel. The technique has been successfully evaluated with a set of phantom experiments. Following this, quantifications of the blood flow rates in vivo were performed on the abdominal aortas of healthy volunteers. The MR flow results were compared to those obtained with conventional Doppler ultrasound examinations. The results of both methods are in good quantitative agreement.

Aorta↗
PubMed1988

Isolation and partial characterization of a bacteriophage active on Hyphomicrobium sp. WI-926.

Isolation of a Hyphomicrobium phage from raw sewage from Athens, Ohio, was achieved by a combination of differential centrifugation, filtration, enrichment in mixed Hyphomicrobium cultures, and purification on individual host strains by subculturing single plaques in soft agar overlayers. Enrichments with water from Lake Erie and Lake Beechwood (Ohio) were unsuccessful. Out of 21 Hyphomicrobium strains and 22 other Gram-negative and Gram-positive bacteria tested, only Hyphomicrobium WI-926 (isolated from a German forest pond) was susceptible. This phage had an isometric head (diameter between opposite apices, 67 nm) and a short (12 nm), noncontractile tail and belongs thus to the morphogroup C1. It contained double-stranded DNA. The single-step growth curve showed a latent period of 9 h, a rise period of 6 h, and a burst size of 35. The various differentiation stages in the host development exhibited different affinities for phage adsorption and development. While all stages allowed phage adsorption, the daughter cells were most efficient. Phage multiplication was limited to daughter cells, and the development of infected swarmer cells was arrested permanently at this stage.

Bacteria↗
PubMed1980

Differential inactivation of three bacteriophages by acid and alkaline pH used in the membrane adsorption-elution method of virus recovery.

The study was prompted by our inability to concentrate phages by a membrane adsorption method effective for polioviruses. Consequently two coliphages WPK and T4, and F116 of Pseudomonas aeruginosa were tested for their resistance to acid (pH 5.2-3.2) and alkaline (pH 10-11.5) exposures. Only T4 proved acid resistant allowing for acid adsorption, and only WPK was sufficiently alkaline resistant to allow for alkaline elution. Thus, the differential susceptibility of various phages precludes the use of the acid membrane adsorption-alkaline elution method as a general method for the concentration of phages from large volumes of water.

Bacteriophages↗
PubMed1979

Biosynthesis of streptomycin. Enzymic oxidation of dihydrostreptomycin (6-phosphate) to streptomycin (6-phosphate) with a particulate fraction of Streptomyces griseus.

Resting cells and to a greater extent permeabilized cells of Streptomyces griseus can oxidize dihydrostreptomycin to streptomycin. The dihydrostreptomycin oxidoreductase activity was localized in the 100,000 X g particulate fraction. Sucrose density gradient centrifugation of the particulate suspension gave a band at a density of 1.09 which consisted mainly of membrane vesicles. This fraction had high dihydrostreptomycin oxidoreductase activity. S. griseus protoplasts also contain high oxidoreductase activity. These data are consistent with localization of the enzyme in the cell membrane. Dihydrostreptomycin and dihydrostreptomycin 6-phosphate can both serve as substrates for the oxidoreducatase, but the phosphate was the better substrate in the cell free system. Addition of cofactors was not required for the bound dihydrostreptomycin oxidoreductase. The electron acceptor for the oxidation is unknown. Oxidation of dihydrostreptomycin 6-phosphate to streptomycin 6-phosphate very probably represents the penultimate step in the biosynthesis of streptomycin.

Centrifugation, Density Gradient↗
PubMed1977

Correction for the inherent error in optical density readings.

Except at very low levels, uncorrected photometric determination of bacterial cell densities showed a decreasing proportionally to actual cell density or dry weight. A standard curve was prepared to convert photometric readings to truly proportional optical density values. With one dry weight determination, optical density values may be converted to absolute dry weight values.

Escherichia coli↗
PubMed1977

[4-7 year results of total hip arthroplasty with special reference to late complications].

The 4-7 year results of total hip arthroplasty (95 hips, McKee-Müller and Charnley-Müller) are presented in detail both from a clinical and radiological point of view. About 83% of the hips showed a good and excellent clinical condition at the time of reevaluation. Deep infection was observed in 4.2% of the hips, 11.2% of the hips had already been reoperated at the time of reevaluation because of aseptic loosening of one or both components. Another 3.5% of the hips showed clinical and radiological evidence of aseptic loosening, some more 4.9% of the hips had radiological evidence of loosening without clinical signs at the time of reevaluation. Furthermore, 6.8% of the hips had radiological evidence of third degree periarticular calcification influencing the clinical state of the hip in a negative manner. Over all serious complications which gave or will give rise to reoperation were 30.6%. The causes for serious complications are discussed extensively. It is proposed to restrict indication for total hip arthroplasty and to reemphasize hip-conserving procedures more seriously.

Adult↗
PubMed1975

Fine structure of mesosomal involvement during Bacillus macerans sporulation.

The ultrastructure of endospore formation in Bacillus macerans ATCC 8244 is characterized by the examination of thin sections of cells grown synchronously in a defined medium. For the most part, sporulation in this organism proceeds as described in other Bacillus species. However, unusually extensive mesosomal involvement occurs during the early stages of sporulation, through the completion of engulfment. A large mesosome is associated with spore septum formation and a portion of this mesosome is included in the developing forespore. As engulfment continues, the forespore mesosome moves to the apex of the cell and participates in the completion of the double forespore membrane. This participation is morphologically similar to mesosome involvement in division and spore septation and seems to comprise a second sporal septation process. Based on this study, it is suggested that the mesosome functions to facilitate the "fusion" of membranes thought to occur during cell division and sporulation.

Bacillus↗
PubMed1975

Two modifications making membrane filtration more economical.

Two economical membrane filtration techniques are described: (1) vacuum filtration through a single funnel into several sterile containers and (2) pressure filtration using an inexpensive combination of pressure source, vessel, and valve.

Bacteriological Techniques↗
PubMed1970

Improved automatic inoculator for bacterial cultures.

A simple automatic inoculator which allows the simultaneous inoculation of several cultures with identical or different inocula is described. The use of Teflon spaghetti tubing allows great flexibility in handling and placing of components. The inoculator can be adapted to handle aerobic and anaerobic bacteria.

Automation↗