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PubMed2005

Using mobile technologies to give health students access to learning resources in the UK community setting.

OBJECTIVES: This article describes a project which explored the potential for mobile technologies to give health students in the community access to learning resources. The purpose included the need to identify possible barriers students could face in using mobile technologies. Another focus was to assess the students perceptions of the importance of being able to access learning resources in the community. METHODS: This 1-year project used two main approaches for data collection. A review of the literature on mobile technologies in the health context was conducted. This was used in a systematic way to identify key issues and trends. The literature review was used to inform the design and production of a questionnaire. This was distributed to and completed by a group of community health students at Northumbria University, UK. The questionnaire was piloted and there was a 100% completion rate with 49 returned forms. RESULTS: The literature review indicated that most mobile technology applications were occurring in the US. At the time of the review the most prevalent mobile technologies were PDAs, laptops, WAP phones and portable radios with use being concentrated around doctors in the acute sector. A range of advantages and disadvantages to the technology were discovered. Mobile technologies were mainly being used for clinical rather than learning applications. The students showed a low level of awareness of the technology but placed great importance to accessing learning resources from the community. CONCLUSIONS: Significant development and changes are taking place in mobile technologies. Since the data collection for this work was completed in 2004 podcasting and videocasting have become significant in mobile learning for health professionals. Librarians will need to address the relevance and implications of m-learning for their practice. Care and consideration needs to be given on the time and resources librarians allocate for the necessary development work around mobile technologies. Collaboration and partnership working will be most effective approach for librarians wishing to integrate their services with m-learning technologies.

Computer Communication Networks↗
PubMed1997

A comparative analysis of the transplant potential of umbilical cord blood versus mobilized peripheral blood stem cells.

Human umbilical cord blood (UCB) is currently considered as a third source of hematopoietic stem cells for transplantation, following the bone marrow and growth-factor-mobilized peripheral blood (MPB). To evaluate the potential benefits of UCB, we performed a comparative study of the properties of the stem cells in UCB and MPB samples. CD 34+ cell determination and CFU-GM colony assay showed a lower frequency of committed progenitors in UCB than in MPB. In contrast, a higher of the CD 34+ CD 38- subset in UCB suggested that more primitive, multipotent progenitors are enriched in UCB than in MPB. Phenotypic analysis of UCB lymphocytes revealed a reduced level of T cell subsets, especially cytotoxic CD 8+ lymphocytes, which might minimize graft versus host disease in clinical practice. In conclusion, UCB is an attractive alternative source for stem cell transplantation, but ex vivo expansion of stem/progenitor cells could be effective for attaining rapid and safer hemopoietic reconstruction.

Blood Cell Count↗
PubMed1994

The effect of cyclic AMP elevating agents on bradykinin- and carbachol-induced signal transduction in canine cultured tracheal smooth muscle cells.

1. The effects of cholera toxin (CTX), forskolin and dibutyryl cyclic AMP on bradykinin (BK)- and carbachol-induced accumulation of inositol phosphates (IPs) and Ca2+ mobilization were investigated in canine cultured tracheal smooth muscle cells (TSMCs). The BK-induced responses were mediated via a G protein which was not inhibited by CTX or pertussis toxin treatment. 2. BK-stimulated IPs accumulation and Ca2+ mobilization were potentiated by CTX (10 micrograms ml-1) pretreatment which was time-dependent. Maximal increase of these responses occurred after 24 h treatment with CTX. The concentration-effect relationship of BK-induced responses were shifted to the left and BK was substantially more effective in CTX-treated cells than in the control cells. This enhancing effect of CTX did not occur with carbachol. 3. Short-term (< 4 h) treatment with forskolin (10 microM) or dibutyryl cyclic AMP (1 mM) failed to accentuate BK-induced responses, but long-term (> 4 h) treatment of TSMCs with these agents mimicked the enhancing effect of CTX, suggesting that CTX-induced enhancement of BK responsiveness might be due to a rise in cyclic AMP. 4. Prolonged treatment of TSMCs with these agents was accompanied by an increase in cell surface [3H]-BK binding sites, which was inhibited by concurrent incubation with cycloheximide, an inhibitor of protein biosynthesis. Cycloheximide also abolished the potentiating actions of CTX, forskolin, and dibutyryl cyclic AMP on BK-induced IPs formation and Ca2+ mobilization. 5. The locus of this enhancement was further investigated by examining the effects of CTX, forskolin and dibutyryl cyclic AMP on A1F4(-)-induced IPs accumulation in canine TSMCs. AIF4-induced IPs accumulation was not affected by CTX, forskolin, or dibutyryl cyclic AMP treatment, supporting the contention that this stimulatory effect is located at the BK receptor level.6. These results demonstrate that the augmentation of BK-induced IPs accumulation and Ca2+mobilization produced by CTX, forskolin and dibutyryl cyclic AMP involves a cyclic AMP-dependent mechanism which is induced by a sustained increase in the level of intracellular cyclic AMP. CTX and forskolin may promote an increase of the synthesis of BK receptors, and thereby enhance BK-induced responses.

Animals↗
PubMed1997

Environmental fate of trifluralin.

Trifluralin, a preemergence, soil-applied and soil-incorporated herbicide, has been in agricultural use since 1963. The environmental chemistry and fate of dinitroaniline herbicides, including trifluralin, has been studied extensively in agricultural soils. Probst et al. (1975) and Helling (1976) have summarized pre-1975 data on the mobility, persistence, and degradation or metabolism of dinitroaniline herbicides as a group. Since then, numerous studies have been carried out on the fate of dinitroanilines, especially trifluralin, in the environment to understand further their degradation in soil, potential for mobility and persistence, and environmental concentration in water and air. The present review, while summarizing briefly earlier data, concentrates primarily on the post-1975 data on degradation, mobility, and persistence of trifluralin in soils and its potential concentrations in water and air. Trifluralin is readily degraded under sunlight in all media, with half-lives (t1/2) of minutes to several months, depending on the substrate. In addition, other dissipation processes, such as microbial and chemical, are also operative in soils, water, and sediments. Several degradation products of trifluralin have been identified and characterized, both under photolysis and following aerobic and anaerobic metabolism in soils and water-sediment systems. The differences between various degradative pathways of trifluralin appear to be more quantitative than qualitative in nature, leading eventually to the same end products that are subject to binding or mineralization with time. The general lack of accumulation of the breakdown products of trifluralin suggests that these are also subject to the same degradative mechanisms as the parent compound. Trifluralin has low water solubility and is strongly bound to soil components; mean Koc values range from 4,000 to 13,000. Once applied and incorporated into the soil, trifluralin remains relatively immobile with minimal or no potential for contamination of groundwaters under or near the treated zones. Trifluralin residues in soil surface layers are subject to loss via transport in runoff water or volatilization into the air. Seasonal losses in surface runoff are consistently less than 0.5% of the amounts applied, with concentrations in edge-of-the-field run-off water typically < 1.0 microgram L-1. Consequently, trifluralin is infrequently detected in surface waters and, if present, usually occurs below levels of quantification. Seasonal trifluralin losses into the atmosphere can be as high as 25% of that applied. Maximum trifluralin residues in the air above treated fields are in the 2-3 micrograms m-3 range following application, decreasing to < 100 ng m-3 in ambient air of intensive use areas, indicating its rapid dissipation in air. Trifluralin residues at < 100 pg m-3 in the atmosphere of remote nonuse regions have been reported, suggesting its potential for long-range transport. However, there is a general lack of understanding of the mechanisms controlling its potential for long-distance transport, especially considering its rapid photodegradation in vapor and solution states. The persistence of trifluralin in agricultural soils following incorporation is highly variable, depending on several factors such as depth of incorporation, soil moisture, soil temperature, soil air, and soil organic matter content. Estimated half-lives under a variety of agronomic conditions range from 25 to > 201 d, thus categorizing its persistence from 'moderate' to 'persistent'. The estimated half-life data for trifluralin under agronomic conditions, however, cannot be extrapolated to other potential scenarios, such as its dissipation in nontarget areas where trifluralin residues, if any, are essentially deposited on surfaces. Surface deposits on nontarget areas, unlike soil-incorporated residues, would be subject to volatilization and photolysis and thus more short lived. (ABSTRACT TRUNCATED)

Canada↗
PubMed1995

Do European GSM mobile cellular phones pose a potential risk to pacemaker patients?

A series of in vivo trials were carried out in order to verify whether the electromagnetic field radiated by GSM (Groupe Systemes Mobiles) mobile cellular phones might affect implanted pacemakers. Two European GSM phones of 2-watt power were tested and trials conducted on 101 pacemaker implanted outpatients attending day hospital for routine check-up, who volunteered for trials. Forty-three pacemaker models from 11 manufacturers were tested in all. When the sensing threshold of the pacemakers was set at a minimum and the antenna of the phone was in direct contact with the patient's chest, interference was detected for 26 implanted pacemakers. Specifically, pulse inhibition in 10 of 101 cases, ventricular triggering in 9 of 46 DDD-VDD pacemakers, and asynchronous pacing in 4 of 52 devices. Pulse inhibition was also observed combined with asynchronous pacing in 1 of 52 cases and with ventricular triggering in 2 of 46 cases. Minimum effect duration was ca. 3 seconds but in 6 cases effects continued as long as the interfering GSM signal was on. No permanent malfunctioning or changes in the programmed parameters were detected. Whenever interference was detected, trials were repeated to determine the maximum sensing threshold at which interference persisted (with the antenna in contact with the skin over the pacemaker). Then maximum distance between antenna and pacemaker at which interference occurred was determined at pacemaker maximum and minimum sensing threshold. Under our experimental conditions electromagnetic interference effects were detected at a maximum distance of 10 cm with the pacemaker programmed at its minimum sensing threshold.(ABSTRACT TRUNCATED AT 250 WORDS)

Electricity↗
PubMed1990

Aspirin potentiates prestimulated acid secretion and mobilizes intracellular calcium in rabbit parietal cells.

The effects of aspirin on gastric acid secretion were studied in isolated rabbit parietal cells (PC). Aspirin (10(-5) M) potentiated histamine-, dibutyryl cyclic AMP (dbcAMP)-, forskolin- and 3-isobutyl-1-methylxanthine-stimulated acid secretion without affecting basal acid secretion. Augmentation of secretagogue-stimulated acid secretion by aspirin was dependent on calcium (Ca2+) since potentiation was blocked by removal of extracellular Ca2+ ([Ca2+]o) or addition of the calcium antagonist lanthanum chloride. Using the Ca2+ probe fura-2, aspirin (10(-6) - 2 X 10(-5) M) rapidly increased intracellular free Ca2+ concentration ([Ca2+]i) in a dose-dependent manner. The source of released Ca2+ was intracellular as demonstrated by depletion of intracellular Ca2+ and [Ca2+]o with EGTA washing. Aspirin did not affect several other signal transduction sites involved in stimulus-secretion coupling, including the H2 receptor, intracellular cyclic AMP (cAMP), inositol 1,4,5, triphosphate (IP3) and H+,K(+)-ATPase. Aspirin decreased PC prostaglandin E2 (PGE2) content by 98%. Exogenous dimethyl PGE2 (dmPGE2) inhibited both histamine-stimulated acid secretion and its enhancement by aspirin. In contrast, dmPGE2 abolished aspirin-induced potentiation of dbcAMP-stimulated acid secretion by augmenting the dbcAMP-stimulated response. These results indicate that aspirin acts at a site beyond the adenylate cyclase/cAMP system and before the proton pump, presumably by releasing Ca2+ from an IP3-independent intracellular storage pool and by inhibiting PGE2 generation.

Adenosine Triphosphatases↗
PubMedDate not supplied

Natural tooth intrusion phenomenon with implants: a survey.

A common assumption when planning for treatment for a fixed partial denture potentially involving an osseointegrated implant is to avoid connection between the implant and natural tooth abutment because of the differences in mobility and potential long-term effects. A large population was surveyed to measure the incidence of natural tooth intrusion in implant-assisted fixed partial dentures (IAFPD) and to try to identify a correlation between type of implant and/or type of connector. Natural tooth intrusion occurred in 3.5% of the patient population specifically treated with IAFPD. No correlation could be made between incidence of intrusion and the type of implant or type of connector used.

Cementation↗
PubMed2002

Peripheral blood stem cells differ from bone marrow stem cells in cell cycle status, repopulating potential, and sensitivity toward hyperthermic purging in mice mobilized with cyclophosphamide and granulocyte colony-stimulating factor.

Peripheral blood stem cells (PBSCs) are increasingly used in autologous stem cell transplantations. We investigated the mobilizing effect of a combined cyclophosphamide (CTX) and granulocyte colony-stimulating factor (G-CSF) treatment on progenitor cells (STRA) and primitive stem cells (LTRA) in normal and splenectomized CBA/H mice. This combined treatment not only resulted in mobilization but also in expansion of hematopoietic stem cell subsets. The latter phenomenon was somewhat suppressed in splenectomized animals, but in these mice an enhanced mobilization of STRA and LTRA cells into the peripheral blood was observed. Furthermore, we studied the engraftment potential of mobilized PBSCs. Mice transplanted with PBSCs engrafted significantly better compared to mice transplanted with bone marrow stem cells from control and mobilized mice. The repopulation curve was characterized by a less-deep nadir indicating that the differences occur during the initial phase after transplantation. Contamination of autologous PBSC transplants with malignant cells is noticed frequently and is the basis for urging the use of purging modalities. Here we used hyperthermia and found that the mobilized progenitor cells in peripheral blood are more resistant to hyperthermia than those in the bone marrow (i.e., a survival of 11 +/- 5% after 90 min at 43 degrees C for peripheral blood progenitors, compared to 0.5 +/- 0.4% in bone marrow of mobilized animals and 1.6 +/- 0.5% in normal animals, respectively). Hyperthermic purging does not eliminate the superior repopulating features of a PBSC graft, as is demonstrated by an increased median survival time of lethally irradiated mice transplanted with purged PBSCs. In conclusion, our data demonstrate that CTX + G-CSF-mobilized PBSCs have an enhanced engraftment potential concomitantly with a decreased cycling activity and hence a decreased hyperthermic sensitivity. These findings support the use of these mobilized PBSCs for autologous stem cell transplantation and strengthen the basis for using hyperthermia as a purging modality.

Animals↗
PubMed1976

[The effect of Staphylococcus toxin on the electrophoretic mobility and the value of zeta-potential of erythrocytes of the BALB strain mice].

In experiments in vitro staphylococcus toxin caused a reduction of the electrophoretic mobility and of the zeta potential of the erythrocytes of the BALB line mice; the extent of this reduction depended on the duration of incubation of the erythrocytes with the toxin. The washing of erythrocytes from the toxin after the incubation led to the restoration of the zeta potential and the electrophoretic mobility to 95% of the initial value, this pointing to the sorption interaction of the toxin with the erythrocyte membranes.

Adsorption↗
PubMed1977

[The effect of roentgen rays on the transmembrane potential and on the electrophoretic mobility of polymorphonuclear granulocytes and FL-cells (author's transl)].

Two hours after X-irradiation at 37 degrees C in vitro at doses ranging from 50 rad to 20 krad the transmembrane potential and the surface charge of polymorphonuclear granulocytes and FL-cells showed a dose-dependent decrease. However, between two and four days after irradiation at 10 krad FL-cells revealed an increase in both transmembrane potential and surface charge. Small doses of ionizing radiation (e.g. 10 rad) resulted in aperiodically damped oszillations of membrane polarisation in leucocytes.

Cell Line↗
PubMed2002

Dynamic electrophoretic mobility of a concentrated dispersion of particles with a charge-regulated surface at arbitrary potential.

The dynamic electrophoretic mobility of a concentrated dispersion of biocolloids such as cells and microorganisms is modeled theoretically. Here, a biological particle is simulated by a particle, the surface of which contains dissociable functional groups. The results derived provide basic theory for the quantification of the surface properties of a biocolloid through an electroacoustic device, which has the merit of making direct measurement on a concentrated dispersion without dilution. Two key parameters are defined to characterize the phenomenon under consideration: the first, A, is associated with the pH of the dispersion, and the second, B, is associated with the equilibrium constant of the dissociation reaction of the functional group. We show that if A is large and/or B is small, the surface potential is high, and the effect of double-layer polarization becomes significant. In this case the dynamic electrophoretic mobility may have a local maximum and a phase lead as the frequency of the applied electric field varies. Due to the hydrodynamic interaction between neighboring particles, the dynamic electrophoretic mobility decreases with the concentration of dispersion.

Journal Article↗
PubMed1994

Molecular dynamics simulations of HIV-1 protease with peptide substrate.

Molecular dynamics simulations of human immunodeficiency virus (HIV)-1 protease with a model substrate were used to test if there is a stable energy minimum for a proton that is equidistant from the four delta oxygen atoms of the two catalytic aspartic acids. The crystal structure of HIV-1 protease with a peptidic inhibitor was modified to model the peptide substrate Ser-Gln-Asn-Tyr-Pro-Ile-Val-Gln for the starting geometry. A proton was positioned between the two closet oxygen atoms of the two catalytic aspartic acids, and close to the carbonyl oxygen of the scissile bond in the substrate. All crystallographic water molecules were included. Two molecular dynamics simulations were run: 30 ps with united-atom potentials and 40 ps using the more accurate all-atom potentials. The molecular dynamics used a new algorithm that increased the speed and allowed the elimination of a cut-off for non-bonded interactions and the inclusion of an 8 A shell of water molecules in the calculations. The overall structure of the protease dimer, including the catalytic aspartic acids, was stable during the course of the molecular dynamics simulations. The substrate and a water molecule, that is an important component of the binding site, were stable during the simulation using all-atom potentials, but more mobile when united-atom potentials were used. A Poincare map representation showed that the positions of the proton and its coordinating oxygen atoms were stable for 93% of both simulations, although many of the buried and poorly accessible water molecules exchanged with solvent. The proton has a stable minimum energy position and maintains coordination with all four delta oxygen atoms of the two catalytic aspartic acids and the carbonyl oxygen of the scissile bond of the substrate. Therefore, a loosely bound hydrogen ion at this position will not be rapidly exchanged with solvent, and will rebond to either a catalytic aspartic acid or possibly the substrate. The implications for the reaction mechanism are discussed.

Amino Acid Sequence↗
PubMedDate not supplied

Overarching principles and salient findings for inclusion in guidelines for power mobility use within residential care facilities.

Although power mobility has many potential benefits for users, power mobility incidents and accidents are a serious concern. To date, little research has explored power mobility safety, and no gold standard exists to determine whether the user is a safe driver. As a possible alternative to a facility unilaterally imposing regulations on power mobility users, we conducted a research project in which power mobility users and other stakeholders used the Delphi method to develop guidelines for power mobility use within a residential facility setting. This article presents the overarching principles for power mobility use and noteworthy items from the safety guidelines that participants developed. These findings highlight the safety issues that are encountered in residential care settings and suggest some strategies to deal with them.

Aged↗
PubMed2005

Involvement of Ca2+ signaling in tachykinin-mediated contractile responses in swine trachea.

Neuropeptide tachykinins, present within sensory nerves, have been implicated as neurotransmitters involved in nonadrenergic and noncholinergic airway muscle contraction. The signal transduction pathways of tachykinins on muscle contraction and Ca2+ mobilization were investigated in swine trachea. Tachykinins, substance P (SP) and neurokinin A (NKA), concentration (1 nM to 1 microM)-dependently induced contractile responses with removal of epithelium, whereas neurokinin B (NKB) did not alter the muscle tension. The SP- and NKA-evoked muscle contractions were inhibited by NK1-R antagonist L732138, but not by either NK2-R antagonist MDL29913 or NK3-R antagonist SB218795. Consistently, SP-elicited increase in [Ca2+]i was abolished by NK1-R antagonist, neither by NK2-R nor NK3-R antagonists. The SP-induced muscular responses were significantly inhibited by L-type Ca2+ channel blocker verapamil and withdrawal of external Ca2+. Caffeine (10 mM) or ryanodine (50 microM) also partly suppressed the SP-induced muscle responses. Inhibition of inositol 1,4,5-trisphosphate (InsP3) receptor with 2-APB (75 microM) potently attenuated SP-evoked Ca2+ mobilization and muscle contraction, which was further inhibited by 2-APB under Ca2+-free external solution, but not completely. Unexpectedly, simultaneous blockade of InsP3 receptor and ryanodine receptor (RyR) by 2-APB and ryanodine enhanced SP-evoked muscle contraction and Ca2+ mobilization. This potentiation was virtually abolished by removal of external Ca2+, suggesting native Ca2+ channels may contribute to this phenomenon. These results demonstrate that tachykinins produce a potent muscle contraction associated with Ca2+ mobilization via tachykinin NK1- R-dependent activation of multiple signal transduction pathways involving Ca2+ influx and release of Ca2+ from InsP3- and ryanodine-sensitive Ca2+ stores. Blockade of both InsP3 receptor and RyR enhances the Ca2+ influx through native Ca2+ channels in plasma membrane, which is crucial to Ca2+ signaling in response to NK1 receptor activation.

Animals↗
PubMed1999

Mobilization of heavy metals from Le An River sediment.

The release of sediment-bound heavy metals can have a significant influence on river water quality. Generally speaking, variations of pH and oxygen are among the most important chemical factors that affect the mobility of sediment-bound metals. Recent research has indicated that sulfide, measured as acid-volatile sulfide (AVS), is an important partitioning component of heavy metals. We determined the metal release potential of sediments from the Le An River which receives drainage from a major copper mining operation. We found that the in-situ Cu, Pb, Zn, Cd and As concentrations of the Le An River sediments below the mine are much higher than are the global background values, but that Ni was not elevated. There is potential for mobilization of bound metals to the overlying water, the order of metal release ratio in terms of pH dependencies is Zn > Cu > Cd approximately Pb. Sulfide is not a major binding component for metals in Le An River sediment. It is more likely that the iron and manganese oxides are the most important metal binding components in the sediments of the Le An River.

China↗
PubMed1989

[Characteristics of the combined action of melatonin and imizin on the structure of forced swimming and the circadian rhythm].

Acute administration of melatonin (10 mg/kg) produced a depressed effect on the mice behavior. But it's injection after chronic imipramine (10 mg/kg/day, 2 weeks) potentiated antidepressant ability and shortened the duration of immobility in the structure of swimming. In rats, which had a high amplitude of circadian rest-activity rhythm, melatonin produced imipramine effect on circadian mobility, but potentiated antidepressant action in animals with low initial level of locomotor activity.

Animals↗
PubMed1997

Use of stem cell factor to mobilize hematopoietic progenitors.

Stem cell factor (SCF) is a multipotent growth factor that plays a role in the growth and development of hematopoietic cells, spermatocytes, melanocytes, and mast cells. SCF alone has little direct stimulatory activity on hematopoietic progenitors but acts synergistically with other colony-stimulating factors to potentiate their effects on colony growth. SCF also potentiates the mobilization of hematopoietic progenitor cells into the peripheral blood in response to granulocyte colony-stimulating factor (G-CSF), with or without chemotherapy. The combination of SCF plus G-CSF appears to be a particularly effective mobilization regimen for patients who have been heavily pretreated. Whether engraftment of peripheral blood progenitor cells mobilized by SCF plus G-CSF is superior to that of cells mobilized by G-CSF alone remains unclear. SCF appears to be a necessary requirement for ex vivo expansion of hematopoietic progenitors in both liquid and bioreactor culture systems and will be an important component of future cellular therapies, such as expansion of placental cord blood progenitors and retroviral-mediated gene transfer into hematopoietic target cells.

Animals↗