Biomedical subjects

R Wagner

Publications and source records attributed to R Wagner.

At least 19 recordsLinked to original sources

PubMed2006

Effect of the exchange of substituent position in an amide amphiphile on the monolayer characteristics.

The monolayer characteristics of two very similar amphiphiles, N-tridecyl-beta-hydroxypropionic acid amide (C13H27-NH-CO-C2H4OH; THPA) and N-(beta-hydroxyethyl)tridecanoic acid amide (C13H27-CO-NH-C2H4OH; HETA), the chemical structure of which is only changed by exchanging the position of the two substituents at the acid amide group, are compared. These small changes in the chemical structure give rise to large differences in the phase behavior of the HETA and THPA monolayers, as concluded from the differences in the surface pressure-area (pi-A) isotherms. Since both amphiphiles have the same alkyl chain length, the shift of the fluid/condensed phase transition pressure pi(c) to higher temperatures from THPA to HETA indicates a stronger polar character of the THPA headgroup. Considerable differences between the HETA and THPA monolayers also exist in the domain morphology, although, in both cases, six arms usually grow from a round center. The fractal-shaped HETA domains grow by tip splitting under the formation of numerous doubloons so that branching is considerably limited. This suggests a certain fluidity of the HETA condensed phase. The main differences of the domains result from the higher crystallinity. The starlike THPA domains have dendritic character and can form curved dendrites, which are partially two-dimensional twins due to the formation of dislocations in the two-dimensional lattice structure. In the case of HETA monolayers, the grazing incidence X-ray diffraction studies reveal a hexagonal packing of the alkyl chains oriented perpendicularly to the surface in an LS phase. In the case of THPA monolayers, an oblique lattice is formed. However, at low temperatures, a second phase transition between two condensed phases occurs that is demonstrated by an abrupt transition between two different oblique lattice structures at the surface pressure where a cusp in the pi-A isotherms occurs at T < 10 degrees C.

Journal Article↗

PubMed2006

Cassini observes the active south pole of Enceladus.

Cassini has identified a geologically active province at the south pole of Saturn's moon Enceladus. In images acquired by the Imaging Science Subsystem (ISS), this region is circumscribed by a chain of folded ridges and troughs at approximately 55 degrees S latitude. The terrain southward of this boundary is distinguished by its albedo and color contrasts, elevated temperatures, extreme geologic youth, and narrow tectonic rifts that exhibit coarse-grained ice and coincide with the hottest temperatures measured in the region. Jets of fine icy particles that supply Saturn's E ring emanate from this province, carried aloft by water vapor probably venting from subsurface reservoirs of liquid water. The shape of Enceladus suggests a possible intense heating epoch in the past by capture into a 1:4 secondary spin/orbit resonance.

Extraterrestrial Environment↗

PubMed2006

[Administering drugs to infants, children, and adolescents].

In many cases, pharmaceutical manufacturers do not embark on lenghty licencing procedures for pediatric medications. Therefore, formulations and dosages suitable for children are often not available, and even medications that have been approved for pediatric use sometimes lack the information and tools required for correct usage. Therefore, choosing a suitable medication that allows for individual dosing, taking into account physiological peculiarities, providing appropriate tools and comprehensive information for parents and/or nursing staff is vital to the success of drug treatments in pediatric patients.

Adolescent↗

PubMed2005

Review of 15 cases of pemphigus foliaceus in horses and a survey of the literature.

The records of 15 horses with pemphigus foliaceus diagnosed on the basis of their history, clinical signs, histopathology and the exclusion of differential diagnoses were evaluated with respect to the age of onset, the clinical signs and the diagnostic tests used. There was no apparent breed predisposition. The horses' mean age was nine years, with a range from three months to 25.5 years, three were foals up to six months old and eight were nine years old or older. The most frequent lesions were scaling in 11, crusting in 10 and alopecia in 10, and they appeared most commonly on the face, neck and trunk, in 10 horses for each of these sites. The extremities were involved in nine of the horses, pruritus occurred in seven, and four of the horses had pustules. The clinical signs mostly corresponded with those described in previous reports, but signs of pain were not a prominent feature. Acantholytic cells were identified cytologically in four of six of the horses.

Animals↗

PubMed2005

A new approach to an influenza live vaccine: modification of the cleavage site of hemagglutinin.

A promising approach to reduce the impact of influenza is the use of an attenuated, live virus as a vaccine. Using reverse genetics, we generated a mutant of strain A/WSN/33 with a modified cleavage site within its hemagglutinin, which depends on proteolytic activation by elastase. Unlike the wild-type, which requires trypsin, this mutant is strictly dependent on elastase. Both viruses grow equally well in cell culture. In contrast to the lethal wild-type virus, the mutant is entirely attenuated in mice. At a dose of 10(5) plaque-forming units, it induced complete protection against lethal challenge. This approach allows the conversion of any epidemic strain into a genetically homologous attenuated virus.

Animals↗

PubMed2005

Blood phagocyte activation during open heart surgery with cardiopulmonary bypass.

Open heart surgery with a cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response which significantly contributes to adverse postoperative complications. The purpose of this study was to characterize the activation of blood phagocytes during open heart surgery with CPB. Blood samples were collected during and up to 24 h after surgery. The production of reactive oxygen species (ROS) in whole blood, the expression of surface molecules by blood phagocytes and complement activity in the plasma were determined. A cDNA microarray analysis of leukocyte RNA profile of genes was performed related to the inflammatory response. Activation of the complement was already observed at the beginning of CPB. This was followed by an increase in the neutrophil number and in both spontaneous and opsonized zymosan-activated ROS production after the onset of reperfusion. The activation of blood phagocytes was affirmed by changes in surface receptors involved in the adhesion and migration of leukocytes (CD11b, CD62L and CD31). Gene arrays also confirmed the activation of leukocytes 4 h after reperfusion. In conclusion, open heart surgery with a cardiopulmonary bypass was found to be associated with a rapid and pronounced activation of blood phagocytes and complement activation which was partly independent at the onset of CPB.

Aged↗

PubMed2005

Cassini Imaging Science: initial results on Saturn's atmosphere.

The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.

Atmosphere↗

PubMed2005

Cassini Imaging Science: initial results on Phoebe and Iapetus.

The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.

Extraterrestrial Environment↗

PubMed2005

Cassini Imaging Science: initial results on Saturn's rings and small satellites.

Images acquired of Saturn's rings and small moons by the Cassini Imaging Science Subsystem (ISS) during the first 9 months of Cassini operations at Saturn have produced many new findings. These include new saturnian moons; refined orbits of new and previously known moons; narrow diffuse rings in the F-ring region and embedded in gaps within the main rings; exceptionally fine-scale ring structure in moderate- to high-optical depth regions; new estimates for the masses of ring-region moons, as well as ring particle properties in the Cassini division, derived from the analysis of linear density waves; ring particle albedos in select ring regions; and never-before-seen phenomena within the rings.

Journal Article↗

PubMed2005

[The Würzburg polytrauma algorithm. Concept and first results of a sliding-gantry-based computer tomography diagnostic system].

BACKGROUND: The purpose of this study was to show the practicability of a new algorithm in the management of polytraumatized patients based on Advanced Trauma Live Support (ATLS) and using mobile whole body multislice CT (MMDCT) as the primary imaging system. PATIENTS AND METHODS: A series of 120 trauma patients referred to the Würzburg University Hospital Trauma Emergency Room were categorized into suspected polytrauma and suspected non-polytrauma groups. The polytraumatized patients were investigated using the Würzburg polytrauma-algorithm including whole body multislice CT with a 16-row-scanner. The algorithm is described. The time for the diagnostic procedure was measured and compared with data from the Trauma Registry of the German Society of Trauma Surgery. RESULTS: From 120 patients 78 (66%) underwent whole body CT. The diagnostic procedure was quick with significant advantages especially for cranial and trunk diagnostics. CONCLUSION: The Würzburg polytrauma algorithm worked well. There was excellent cooperation within the interdisciplinary leading team consisting of anaesthesiologists, surgeons, and radiologists. The principles of ATLS could be respected. Mobile whole body multislice CT was an effective tool in the diagnostic evaluation of polytrauma patients.

Algorithms↗

PubMed2005

["The fungal jungle". Medical mycology on the Internet].

The World Wide Web offers an enormous variety of information about medical mycology. To go through the "fungal jungle" and find the website containing the information that is needed requires a great deal of effort and a lot of time. This article provides help in finding information about medical mycology and describes the contents of preselected websites in German and English. These pages address physicians, scientists, and students interested in dermato-mycology. Most of the pages also contain information about mycoses relevant to other medical specialties.

Databases, Bibliographic↗

PubMed2005

Multinucleate storage cells in Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) and the effect of seed parasitism by the chalcid Megastigmus spermotrophus Wachtl.

Megagametophytes of Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) accumulated storage products following fertilization. As megagametophytes matured, the number of nuclei per cell rose, resulting in syncytial storage cells. Studies carried out on trees in France and Canada confirmed that such previously unreported, free nuclear cells were a normal part of late megagametophyte development. Unfertilized megagametophytes showed that some binucleate cells before degeneration resulted in empty seed. Insect parasitism prevented megagametophyte abortion in unfertilized ovules. Oviposition by a torymid chalcid wasp (Megastigmus spermotrophus Wachtl) early in megagametophyte development resulted in normal megagametophyte development. Around the time of plant egg maturation, binucleate and trinucleate cells were observed. As megagametophytes matured, multinucleate mature storage cells rich in proteins, lipids and starch were formed. The insect was able to induce identical nuclear behaviour in infested, unfertilized megagametophytes, as that of uninfested, fertilized megagametophytes.

Animals↗

PubMed2005

Performance evaluation of IVC systems.

An expert Working Group was set up in December 2000 to develop recommendations for users and industry on the evaluation of proper function and operation of individually ventilated cage (IVC) systems. The full report of their recommendations is in two parts--'Part 1: Test Instructions' and 'Part 2: Evaluation Criteria'--both of which have been published in full on the Laboratory Animals Ltd website. They can be found at http://www.lal.org.uk/IVC/index.html. Evaluation of and feedback on the recommendations to further refine their use and scientific basis is encouraged. This Summary Report provides a brief overview of the background to the development of the full report and the issues it addresses.

Animal Welfare↗

PubMed2004

Effects of chlorpromazine on excitation-contraction coupling events in fast-twitch skeletal muscle fibres of the rat.

1. Single mechanically skinned fibres from the rat extensor digitorum longus muscle, which allow access to intracellular compartments, were used to examine the effects of 0.5-100 microM chlorpromazine hydrochloride (CPZ) on the major steps of the excitation-contraction (E-C) coupling to elucidate the involvement of skeletal muscle in the neuroleptic malignant syndrome (NMS). 2. At 1 microM, CPZ caused a 20-30% increase in the force response induced by t-system depolarisation and a marked increase in the rate of caffeine-induced SR Ca(2+) release. At [CPZ]> or =2.5 microM, there was an initial increase followed by a marked decrease of the t-system depolarisation-induced force responses, while the potentiating effect on the caffeine-induced SR Ca(2+) release remained. These effects were reversible. 3. CPZ had no effect on the maximum Ca(2+)-activated force, but caused reversible, concentration-dependent increases in the Ca(2+) sensitivity of the contractile apparatus at [CPZ] > or =10 microM, with a 50% predicted shift of 0.11 pCa (-log [Ca(2+)]) units at 82.3 microM CPZ. 4. CPZ did not alter the rate of SR-Ca(2+) loading at 1 and 10 microM, but reversibly reduced it by approximately 40% at 100 microM by reducing the SR Ca(2+) pump. Nevertheless, the SR Ca(2+) content was greater when fibres became unresponsive to t-system-induced depolarisation in the presence than in the absence of 100 microM CPZ. 5. The results show that CPZ has concentration-dependent stimulatory and inhibitory effects on various steps of the E-C coupling, which can explain the involvement of skeletal muscle in NMS and reconcile previous divergent data on CPZ effects on muscle.

Algorithms↗

PubMed2003

PET-based molecular imaging in neuroscience.

Positron emission tomography (PET) allows non-invasive assessment of physiological, metabolic and molecular processes in humans and animals in vivo. Advances in detector technology have led to a considerable improvement in the spatial resolution of PET (1-2 mm), enabling for the first time investigations in small experimental animals such as mice. With the developments in radiochemistry and tracer technology, a variety of endogenously expressed and exogenously introduced genes can be analysed by PET. This opens up the exciting and rapidly evolving field of molecular imaging, aiming at the non-invasive localisation of a biological process of interest in normal and diseased cells in animal models and humans in vivo. The main and most intriguing advantage of molecular imaging is the kinetic analysis of a given molecular event in the same experimental subject over time. This will allow non-invasive characterisation and "phenotyping" of animal models of human disease at various disease stages, under certain pathophysiological stimuli and after therapeutic intervention. The potential broad applications of imaging molecular events in vivo lie in the study of cell biology, biochemistry, gene/protein function and regulation, signal transduction, transcriptional regulation and characterisation of transgenic animals. Most importantly, molecular imaging will have great implications for the identification of potential molecular therapeutic targets, in the development of new treatment strategies, and in their successful implementation into clinical application. Here, the potential impact of molecular imaging by PET in applications in neuroscience research with a special focus on neurodegeneration and neuro-oncology is reviewed.

Alzheimer Disease↗

PubMed2003

[Status and current strategies of HIV vaccine development].

Despite intensive research efforts a vaccine against HIV has not yet been developed twenty years even after the onset of the HIV-epidemic. The problems in the development of an HIV-vaccine as well as former and current strategies to overcome these problems are presented here. The current status of human studies of different candidate vaccines is outlined.

AIDS Vaccines↗

PubMed2003

Inhibition of wild-type human immunodeficiency virus and reverse transcriptase inhibitor-resistant variants by Phyllanthus amarus.

Substantial progress has been made in research on natural products which effectively inhibit HIV-1 replication. Many active compounds were isolated from traditionally used medicinal plants including Phyllanthus species. This study shows that aqueous as well as alcohol-based Phyllanthus amarus extracts potently inhibit HIV-1 replication in HeLa CD4(+) cells with 50% effective concentration (EC(50)) values ranging from 0.9 to 7.6 microg/ml. A gallotannin enriched fraction showed enhanced activity (0.4 microg/ml), and the purified gallotannins geraniin and corilagin were most active (0.24 microg/ml). HIV-1 replication was also blocked in CD4(+) lymphoid cells with comparable EC(50) values. Applying a cell-based internalization assay, we could demonstrate 70-75% inhibition of virus uptake at concentrations of 2.5 microg/ml for the water/alcohol extract and geraniin. In addition, a concentration-dependent inhibition of HIV-1 reverse transcriptase (RT) could be demonstrated in vitro. The 50% inhibitory concentration (IC(50)) values varied from 1.8 to 14.6 microg/ml. The ability to inhibit replication of a variety of RT inhibitor-resistant HIV-1 strains points to the potential of P. amarus extracts, as natural products, in the chemotherapy of HIV infections.

CD4 Antigens↗

PubMed2003

Orthograde retreatment and apexification after unsuccessful endodontic treatment, retreatment and apicectomy.

AIM: To describe a case where a second orthograde retreatment was successful in the management of an infected mandibular right first molar that previously had received both orthograde and retrograde treatments. SUMMARY: Periapical surgery is unlikely to be successful unless the root canal system has been adequately debrided and sealed. A case is described where orthograde endodontic treatment, retreatment and apicectomy were unsuccessful in the management of and infected mandibular right first molar. The periapical radiolucency eventually disappeared following a second orthograde retreatment. Teh second retreatment included 12 months of intracanal calcium hydroxide placement to promote apexification, thus allowing subsequent controlled obturation with gutta percha and AH26. At a 5-year review following completion of treatment, the tooth remained asymptomatic and was in normal function. KEY LEARNING POINTS: Orthograde retreatment is a treatment option to manage refractory lesions in teeth that have previously received endodontic treatment, retreatment and apicectomy. Orthograde retreatment using long-term intracanal calcium hydroxide can help promote root-end closure of a resected apex.

Apicoectomy↗